Forecast Discussions mentioning any of
"HRRR" "RAP" "RR" "RUC13" "RUC" received at GSD on 12/26/13
AREA FORECAST DISCUSSION
NWS DENVER/BOULDER CO
1005 AM MST TUE DEC 24 2013
.UPDATE...
&&
.SHORT TERM...OVERALL...CURRENT FORECASTS LOOK ON TRACK. CHINOOK
WINDS FAIRLY STRONG IN AND NEAR FOOTHILLS...WITH SOME RECENT GUSTS
TO 60 MPH ALONG HIGHWAY 93 FROM BOULDER TO GOLDEN. GUSTY WINDS TO
50 MPH OVER THE HIGHER MOUNTAIN PASSES AS WELL. FAIRLY DECENT
MOUNTAIN TOP INVERSION COMBINING WITH GOOD MOUNTAIN WAVE TO
PRODUCE THE GUSTY AND ERRATIC CHINOOK WINDS. ACROSS THE PLAINS
AWAY FROM THE FOOTHILL...WINDS LIGHTER WITH SOME SORT OF A
ANTICYCLONE IN THE DENVER AREA. SNOW ACROSS MOUNTAINS BEGINNING TO
INCREASE IN COVERAGE AS MID LEVEL ASCENT INCREASES AHEAD OF THE
SHORTWAVE MOVING INTO WYOMING. SPATIAL CROSS SECTIONS STILL
INDICATING A DECREASE IN THE WINDS BY EARLY AFTERNOON...AS CROSS
MOUNTAIN FLOW DECREASES TO AROUND 40 KTS IN RESPONSE TO THE
INCREASING ASCENT. THIS ASCENT WILL HELP BREAK DOWN THE INVERSION.
LATEST MODELS SHOWING ADDITIONAL SNOW AMOUNTS OF AROUND 2 TO 4
INCHES THROUGH THIS AFTERNOON...MAINLY WEST AND NORTHWEST FACING
SLOPES. GUSTY WINDS OVER HIGHER PASSES WILL PRODUCE SOME BLOWING
SNOW. ACROSS PLAINS...APPEARS COLD FRONT IS JUST NORTH OF CHEYENNE.
THERE ARE SOME PRESSURE RISES ACROSS SOUTHERN WYOMING AND NORTHERN
COLORADO. MODELS SHOW FRONT RACING SOUTH BY 20Z..A BIT SLOWER
THAN EARLIER THINKING. WINDS TO BE GUSTY WITH THE FRONTAL
PASSAGE...SOME GUSTS AROUND 40 MPH POSSIBLE EAST OF DENVER AREA.
STILL SOME QUESTION WHETHER THERE WILL BE ENOUGH LOW LEVEL
MOISTURE TO GENERATE SOME LIGHT RAIN OR SNOW SHOWERS.
PRECIPITATION NEAR THE CHEYENNE AREA SHOWINGS SIGNS OF DECREASING.
LATEST RAP AND HRRR DOES SHOW SOME LIGHT QPF ACROSS THE PLAINS
EAST OF DENVER AS WELL AS THE PALMER DIVIDE. CURRENT THINKING IS
THAT THERE WILL BE SUFFICIENT MID LEVEL ASCENT TO PERHAPS SQUEEZE
OUT A FEW SHOWERS BY THE EVENING. THIS STILL SEEMS REASONABLE...
LOW POPS LOOK GOOD FOR NOW. NO ACCUMULATION IS EXPECTED...WITH
PERHAPS A LIGHT DUSTING ALONG THE PALMER DIVIDE. SUBSIDENCE AND
DRIER AIR BEHIND DISTURBANCE THIS EVENING WITH DECREASING SNOW
ACROSS MOUNTAINS. THOUGH WINDS EXPECTED TO DECREASE ACROSS
PLAINS...CROSS SECTIONS SHOW CROSS MOUNTAIN FLOW INCREASING TO 50
KTS AT MOUNTAIN TOP BY MIDNIGHT. WITH THE INCREASING SUBSIDENCE...
WINDS TO INCREASE AGAIN ACROSS THE RIDGES AND EAST SLOPES
OVERNIGHT.
.AVIATION...WEAK CYCLONE DEVELOPING NEAR THE DENVER AREA WITH
LIGHT EASTERLY WINDS AT KDEN AND KAPA. GUSTY WESTERLY WINDS
ONGOING AT KBJC. FRONT JUST NORTH OF CHEYENNE...AND SHOULD RACE
SOUTH ACROSS THE AREA BY 20Z. WILL BACK OFF THE TIMING OF THE
FRONT TO 19Z FOR THE LATEST TAF ISSUANCE. OTHERWISE...REST OF TAF
TRENDS LOOK REASONABLE. GUSTY NORTHERLY WINDS FOR A FEW HOURS
AFTER FROPA THEN DECREASING WITH A GRADUAL CLOCKWISE SHIFT TO
SOUTHERLY THROUGH THE EVENING. STILL A SLIGHT CHANCE FOR A FEW
RAIN/SNOW SHOWERS BETWEEN 20Z AND 02Z WITH PERHAPS CEILINGS AROUND
7000 FEET AGL. NO ACCUMULATION EXPECTED. VFR TO PREVAIL.
&&
.PREV DISCUSSION... /ISSUED 705 AM MST TUE DEC 24 2013/
UPDATE...
AVIATION...UPDATED DENVER AREA TAFS TO REFLECT AN EARLIER ARRIVAL
TIME FOR THE COLD FRONT AND ITS WIND SHIFT. FRONT AT PRESENT TIME
WAS JUST PASSING TORRINGTON IN SOUTHEAST WYOMING. WITHIN THE PAST
30 MINUTES...THE FRONT BLEW THROUGH CASPER WITH IFR CIGS...MODERATE
SNOW AND GUSTY NORTHERN WINDS TO 31 KTS. AT ITS PRESENT SPEED...
COULD SEE THIS FRONTAL BOUNDARY ARRIVING IN THE DENVER AREA BY
18Z OR EVEN 17Z. THAT WOULD BE 2 TO 3 HOURS EARLIER THAN WHAT
MODELS INDICATE. FURTHERMORE...IT MAY BE NECESSARY LATER THIS
MORNING SHOULD IT APPEAR CIGS WILL BE LOWER THAN WHAT IS NOW
INDICATED IN TAFS. HOWEVER...MODELS PRESENTLY DO NOT INDICATE
THIS HAPPENING.
PREV DISCUSSION... /ISSUED 550 AM MST TUE DEC 24 2013/
RESENT...
SHORT TERM...TODAY-TONIGHT: FROM A SYNOPTIC PERSPECTIVE...
700-500 MB TROUGH MOVING ALONG IN STRONG NORTHWEST FLOW STREAM AND
PRESENTLY PASSING OVER IDAHO AND WESTERN MONTANA. AT THE
SURFACE...A PACIFIC COLD FRONT EXTENDS FROM SOUTHERN IDAHO ACROSS
NORTHWEST WYOMING AND SOUTHEAST MONTANA AS OF 09Z. AIRMASS BEHIND
THIS FRONTAL BOUNDARY NOT ALL THAT COLD AS REVEALED BY THE
RAIN...NOT SNOW...FALLING FROM THE CLOUD BAND ALONG THE FRONT
CROSSING SOUTHERN MONTANA. LOWER ELEVATION TEMPERATURES BEHIND THE
FRONT AT THIS HOURS IN THE RELATIVELY MILD 20S AND 30S. MEANWHILE
CLOSER TO HOME...STRONG NORTHWEST FLOW ALOFT COMBINING WITH A
MOUNTAIN WAVE AND INCREASING MTN TOP STABILITY TO CRANK CHINOOK
WIND MACHINE ALONG THE OVER AND NEAR THE FRONT RANGE. GUSTS DURING
THE PAST COUPLE OF HOURS IN THE HIGHER FOOTHILLS OF BOULDER AND
GILPIN COUNTIES IN THE 40-50 MPH RANGE. MODEL SPATIAL CROSS
SECTIONS INDICATE AN INCREASE IN CROSS BARRIER FLOW OVER THE NEXT
FEW HOURS AS THE UPPER TROUGH AND FRONT NEAR. THOSE HIGH WIND
PRONE AREAS...SUCH AS UP AROUND WONDERVU... GEORGETOWN...WARD AND
NEDERLAND IN THE FOOTHILLS WEST OF DENVER AND BOULDER COULD SEE
GUSTS APPROACHING 65 MPH PRIOR TO 12Z. FURTHERMORE A MOUNTAIN WAVE
CLOUD SHIELD HAVE FORMED IN THE LEE OF THE FRONT RANGE WHICH HAS
ALSO HELPED TO PRODUCE MILD OVERNIGHT TEMPERATURES ALONG THE BASE
OF THE FOOTHILLS.
TODAY...STRONG/GUSTY CHINOOK WINDS ARE FORECAST TO EASE THROUGH THE
MORNING AS THE MOUNTAIN WAVE AND CROSS MOUNTAIN PRESSURE GRADIENT
RELAX. UPPER TROUGH AND SFC FRONT WILL RACE SOUTHEAST ACROSS WYOMING
THIS MORNING WITH WHAT LOOKS TO BE A SHRINKING CLOUD/PRECIP BAND AS
THIS SYSTEM ADVANCES INTO A DRIER ENVIRONMENT. THE COLD FRONT IS
TIMED TO REACH THE NORTHEAST COLORADO BORDER BY ABOUT 18Z TODAY...
WHERE IT THEN RACES SOUTH WITH GUSTY NORTHERLY WINDS OF 25-40 MPH
DURING THE AFTERNOON. WRF...HRRR AND NAM MODELS SHOW THE FRONT AND
ITS GUSTY NORTHERLY WINDS REACHING DENVER AND THE I-70 CORRIDOR EAST
OF THE METRO AREA AROUND 21Z (2 PM MST)...AND EXITING SOUTHERN
SECTIONS OF THE CWFA AN HOUR OR SO LATER. GUSTS TO 35-40 MPH WITH
THE FRONT AND FOR AN HOUR OR SO AFTER FROPA...WITH THE STRONGEST
WINDS STAYING EAST OF I-25. WINDS SHOULD DIE DOWN IN THE SOUTHERN
FOOTHILLS WITH FROPA...BUT STRENGTHEN AGAIN OVER NORTHERN SECTIONS
OF THE FRONT RANGE FOOTHILLS WITH STRONG SFC TO MILD-LEVEL
SUBSIDENCE BEHIND THE UPPER TROUGH AXIS FORECAST TO PASS OVER THE
AREA NOT LONG AFTER FRONTAL PASSAGE. COULD ONCE AGAIN SEE NORTHWEST
WINDS GUSTING TO AROUND 50 MPH UP NEAR THE WYOMING BORDER LATE
TODAY. AS FOR PRECIPITATION...WEAK SFC-500 MB QG ASCENT WITH TROUGH
AND FRONT STILL NECESSITATES MENTIONING AT LEAST A SLIGHT CHANCE OF
RAIN/SNOW ON THE PLAINS LATE THIS AFTERNOON. LOOKS TOO DRY FOR ANY
ACCUMULATION...EVEN ON THE PALMER DIVIDE. MOUNTAIN AREAS...SPECIALLY
ALONG AND WEST OF THE CONTINENTAL DIVIDE IN LINE TO SEE SEVERAL
HOURS OF LIGHT TO AT TIMES MODERATE SNOWFALL LATE MORNING THROUGH
EARLY THIS EVENING WITH TROUGH PASSAGE. NEW SNOW AMOUNTS PROBABLY NO
MORE THAN 3-4 INCHES ON HIGHEST WEST-NORTHWEST SLOPES. SNOWFALL
SHOULD QUICKLY SHUT DOWN THROUGH THE EVENING WITH DRYING AND STRONG
SUBSIDENCE. AT THE SAME TIME...RIDGES AND EAST SLOPES COULD SEE
WESTERLY WINDS RAMPING UP AGAIN WITH GUSTS APPROACHING 50 MPH IN
WIND PRONE AREAS OVERNIGHT.
LONG TERM...A RELATIVELY QUIET WEATHER WEAK ACROSS COLORADO AS
HIGH PRESSURE RIDGE ALOFT BUILDS INLAND INTO THE GREAT BASIN
THROUGH FRIDAY. THE RESULT WILL BE A DECREASING NORTHWEST FLOW
PATTERN WITH GENERALLY DRY CONDITIONS AND WARMING TEMPERATURES
FOR WEDNESDAY AND THURSDAY. THERE IS A WEAK RIPPLE IN THE FLOW
THAT BRUSHES FAR NORTHEAST COLORADO LATE THURSDAY BUT THIS FEATURE
LOOKS RATHER DRY EXCEPT FOR SOME MID LEVEL CLOUDINESS. TEMPERATURES
WILL WARM TO WELL ABOVE NORMALS FOR THURSDAY AND FRIDAY WITH
READINGS INTO THE 50S OVER THE PLAINS.
THE NEXT FEATURE WITH POTENTIAL WEATHER AND COOLER TEMPERATURES
WILL MOVE ACROSS COLORADO SATURDAY NIGHT AND EARLY SUNDAY. THE GFS
IS THE DRIER MODEL WHILE THE EUROPEAN HAS MORE MOISTURE AND SOME
LIGHT SNOWFALL OVER COLORADO. GIVEN THE DIFFERENCES AT THIS TIME
WILL KEEP LOW CHANCES OF SNOW FOR THE MOUNTAINS AND PLAINS.
TEMPERATURES WILL BE COOLER AS WELL.
AVIATION...SOUTH-SOUTHWEST WINDS 8-15KTS IN THE DENVER AREA THIS
MORNING...EXCEPT WEST-SOUTHWEST 10-20 KTS WITH OCNL GUSTS TO 30KTS
NEAR THE FOOTHILLS SUCH AS AT BJC. THIS AFTERNOON COLD FRONT RACES
SOUTH THROUGH THE DENVER METRO AREA WITH NORTH WINDS OF 15-25KTS.
HIGHER GUSTS POSSIBLE EAST OF I-25 AROUND 21Z. GUSTY
NORTHWESTERLY WINDS LAST AN HOUR OR SO AFTER FRONTAL
PASSAGE...THEN LIGHTEN UP AS THEY TURN CLOCKWISE THROUGH EARLY
EVENING...AND BECOMING SOUTHERLY 5-10KTS BEFORE 06Z. THERE IS A
SLIGHT CHANCE OF A LIGHT RAN/SNOW SHOWER IN THE DENVER AREA
SHORTLY AFTER FRONTAL PASSAGE. NO SNOW ACCUMULATION WITH
PREVAILING VFR CONDITIONS. THEN CLEARING IN THE EVENING.
&&
.BOU WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...D-L
LONG TERM....ENTREKIN
AVIATION...D-L
AREA FORECAST DISCUSSION
NWS NEW YORK NY
1023 AM EST TUE DEC 24 2013
.SYNOPSIS...
A COLD FRONT MOVES THROUGH THE REGION THIS EVENING FOLLOWED BY
CANADIAN HIGH PRESSURE FOR CHRISTMAS. A WEAK COLD FRONT MOVES
ACROSS THE REGION THURSDAY FOLLOWED BY MORE HIGH PRESSURE BUILDING
IN FROM THE SOUTH AND WEST THROUGH THE WEEKEND. A STRONG COLD
FRONT MOVES ACROSS THE REGION LATE SUNDAY INTO MONDAY.
&&
.NEAR TERM /UNTIL 4 PM THIS AFTERNOON/...
TRICKY NEAR TERM CLOUD COVER FCST TODAY. MID/HIGH CLOUDS OVER LONG
ISLAND MOVING EAST QUICKLY AS UPPER TROF INDUCED CLOUDS OVER PA
MOVE EAST. THIS LEAVES A SUNNY PERIOD FOR THE LUNCH HOUR. WITH
CLOUDS COMING QUICKLY BACK FOR THE AFTERNOON FROM WEST TO EAST.
USED LATEST HRRR AND NSSL WRF CLOUD FIELDS TO DEPICT THIS IN THE
GRIDS.
COLD FRONT NOW RACING THROUGH WEST CENTRAL PA WITH INSTABILITY
SNOW SHOWERS. TIME OF ARRIVAL FOR OUR AREA IS SET FOR EARLY
EVENING. ATMOSPHERE SUPPORTS SNOW, THOUGH SFC TEMPS ABOVE FREEZING
ALONG THE COAST WILL LIKELY PRESENT ISSUES...SEE SHORT TERM
SECTION.
WITH SUNSHINE...HAVE RAISED MAX TEMPS SLIGHTLY WITH MAXES AROUND
40 ALONG THE COAST.
&&
.SHORT TERM /4 PM THIS AFTERNOON THROUGH 6 PM WEDNESDAY/...
LOW LEVEL INSTABILITY IS SIGNIFICANT THIS EVENING WITH SFC TO 950
HPA LAPSE RATES IN EXCESS OF 9 C / KM ALONG WITH NARROW CAPE UP
TO 600 HPA.
THINK WE`RE LOOKING AT SNOW SQUALLS. UNFORTUNATELY, WITH TEMPS
EARLY THIS EVENING ABOVE FREEZING ALONG THE COAST, WE HAVE POTENTIAL
FOR A FLASH FREEZE AS TEMPS DROP QUICKLY.
THE UNCERTAINTY REVOLVES ON THE AMOUNT AND LOCATION OF SNOW.
CURRENTLY, HAVE POPS AT 40% AS THINKING COVERAGE WILL BE AROUND
THIS AMOUNT. TOTALS OF A FEW HUNDREDTHS THOUGH COULD RESULT IS A
SERIOUS TRAVEL ISSUE AS TEMPS FALL RAPIDLY ON STRONG NW FLOW IN
THE WAKE OF THE FRONT.
PLANNING ON ISSUING AN SPS EARLY THIS AFTERNOON.
COLD AIR REMAINS THROUGH MUCH OF CHRISTMAS DAY. THE GFS IS TOO
SLOW TO BRING THE ARCTIC AIR IN AND LEANED TOWARD THE COLDER NAM
GUIDANCE FOR LOWS TONIGHT AND HIGHS CHRISTMAS DAY. WARM ADVECTION
QUICKLY SETS UP LATE IN THE DAY...HOWEVER TOO LATE FOR
TEMPERATURES TO RISE OUT OF THE 20S. TEMPERATURES CHRISTMAS NIGHT
POSSIBLY START TO CLIMB.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH MONDAY/...
A WEAK COLD FRONT WILL PUSH ACROSS THE TRI-STATE AREA DURING THE DAY
ON THURSDAY. THIS FRONT WILL BRING THE REGION SOME CLOUDY SKIES AND
A SLIGHT CHANCE OF SOME SNOW SHOWERS DURING THE DAYTIME. THE FRONT
MOVES EAST OF THE AREA THURSDAY NIGHT AND HIGH PRESSURE OVER THE
SOUTHWEST WILL START TO BUILD INTO THE AREA. THIS HIGH WILL REMAIN
OVER THE AREA THROUGH THE END OF THE WEEK AND FOR MUCH OF THE
WEEKEND BEFORE SLIDING EAST OVER THE ATLANTIC. AN AREA OF LOW
PRESSURE WILL PASS WELL NORTH OF THE REGION SUNDAY AND MONDAY. ITS
ASSOCIATED COLD FRONT WITH APPROACH THE REGION LATE SUNDAY AND MOVE
ACROSS THE AREA LATE SUNDAY INTO MONDAY MORNING.
TEMPERATURES WILL BE RIGHT AROUND NORMAL THURSDAY THROUGH
SATURDAY...THEN RISE SLIGHTLY ABOVE NORMAL ON SUNDAY...BEFORE
FALLING BACK TO NEAR OR BELOW NORMAL ON MONDAY. EXPECT HIGHS IN THE
UPPER 30S AND LOWER 40S EACH DAY...EXCEPT SUNDAY WHEN HIGHS WILL
REACH THE MIDDLE AND UPPER 40S.
&&
.AVIATION /15Z TUESDAY THROUGH SATURDAY/...
AA TROUGH OF LOW PRESSURE WILL MOVE ACROSS THE AREA LATE THIS
AFTERNOON AND INTO EARLY THIS EVENING.
VFR FOR MUCH OF THE DAY AS A BAND OF MID AND HIGH LEVEL CLOUDS EXITS
TO THE EAST THIS MORNING. THERE IS THE POTENTIAL FOR A BRIEF PERIOD
OF IFR CONDITIONS IN SNOW SHOWERS FROM 21Z TO 03Z. RIGHT NOW...THE
NYC METRO TERMINALS...KSWF...KHPN...AND KISP ARE THE MOST FAVORED
LOCATIONS.
NORTH/NORTHWEST WINDS THIS MORNING REMAIN BETWEEN 10 TO 15 KTS.
WINDS WILL BACK 30 TO 50 DEGREES BY LATE THIS AFTERNOON/EARLY THIS
EVENING AHEAD OF THE TROUGH. THE WINDS WILL THEN VEER BACK TO THE
NORTH/NORTHWEST BEHIND THE TROF LATER THIS EVENING AND WILL INCREASE
TO 15 TO 25 KTS LATE THIS EVENING AND OVERNIGHT. GUSTS UP TO 30 KT
POSSIBLE FOR A TIME TONIGHT.
NY METRO ENHANCED AVIATION WEATHER SUPPORT...
DETAILED INFORMATION...INCLUDING HOURLY TAF WIND COMPONENT FCSTS CAN
BE FOUND AT: HTTP:/WWW.ERH.NOAA.GOV/ZNY/N90 (LOWER CASE)
KEWR FCSTER COMMENTS: WINDS TO THE RIGHT OF 310 MAGNETIC THIS
MORNING. AMENDMENTS POSSIBLE FOR A SLIGHT WIND SHIFT BACK TO THE
WEST/NORTHWEST AROUND 310 MAGNETIC LATE THIS AFTERNOON. AMENDMENTS
FOR POSSIBLE SNOW SHOWERS LATE THIS AFTERNOON AND EVENING.
THE AFTERNOON KEWR HAZE POTENTIAL FORECAST IS GREEN...WHICH IMPLIES
SLANT RANGE VISIBILITY 7SM OR GREATER OUTSIDE OF CLOUD.
KJFK FCSTER COMMENTS: WINDS TO THE RIGHT OF 310 MAGNETIC THIS
MORNING. AMENDMENTS POSSIBLE FOR A SLIGHT WIND SHIFT BACK TO THE
WEST/NORTHWEST AROUND 310 MAGNETIC LATE THIS AFTERNOON. AMENDMENTS
FOR POSSIBLE SNOW SHOWERS LATE THIS AFTERNOON AND EVENING.
KLGA FCSTER COMMENTS: WINDS TO THE RIGHT OF 310 MAGNETIC THIS
MORNING. AMENDMENTS POSSIBLE FOR A SLIGHT WIND SHIFT BACK TO THE
WEST/NORTHWEST AROUND 310 MAGNETIC LATE THIS AFTERNOON. AMENDMENTS
FOR POSSIBLE SNOW SHOWERS LATE THIS AFTERNOON AND EVENING.
KTEB FCSTER COMMENTS: AMENDMENTS FOR POSSIBLE SNOW SHOWERS LATE THIS
AFTERNOON AND EVENING.
KHPN FCSTER COMMENTS: AMENDMENTS FOR POSSIBLE SNOW SHOWERS LATE THIS
AFTERNOON AND EVENING.
KISP FCSTER COMMENTS: AMENDMENTS FOR POSSIBLE SNOW SHOWERS THIS
EVENING.
.OUTLOOK FOR 12Z WEDNESDAY THROUGH SATURDAY...
.WED...VFR. DIMINISHING WINDS.
.THU...MAINLY VFR...EXCEPT BRIEF SUB-VFR POSSIBLE IN AFTERNOON SNOW
SHOWERS.
.THU NIGHT-SAT...VFR.
&&
.MARINE...
WITH A SURGE OF ARCTIC COLD AIR THIS EVENING....GUSTS INCREASE TO
SMALL CRAFT LEVELS...AND MAY BRIEFLY APPROACH GALE FORCE ON THE
OUTER WATERS WITH THE INITIAL SURGE OF THE COLD AIR. SO WILL LEAVE
THE ADVISORY ON THE OCEAN WATERS THROUGH TONIGHT.
SMALL CRAFT GUSTS ARE LIKELY ON THE REMAINDER OF THE FORECAST
WATERS TONIGHT...AND ISSUED AN ADVISORY JUST FOR TONIGHT. MAY BE A
BIT TOO LONG AS THE COLD ADVECTION WEAKENS LATE TONIGHT AND WINDS
ALOFT DIMINISH. THEN WINDS AND SEAS WILL BE BELOW SMALL CRAFT
WEDNESDAY. ALTHOUGH SEAS ON THE OCEAN MAY STILL BE AROUND 5 FT
EAST OF MORICHES INLET EARLY IN THE MORNING.
A WEAK COLD FRONT WILL PUSH ACROSS THE AREA WATERS DURING THE DAY ON
THURSDAY...WHICH COULD POSSIBLY BRING SOME SMALL CRAFT STRENGTH
GUSTS TO THE AREA WATERS. BEHIND THIS FRONT...HIGH PRESSURE WILL
BUILD OVER THE AREA WATERS PROVIDING A PERIOD OF SUB-SCA CONDITIONS
FROM THURSDAY NIGHT THROUGH SATURDAY. ANOTHER CHANCE OF SMALL CRAFT
CONDITIONS RETURNS ON SUNDAY WITH THE APPROACH OF ANOTHER COLD
FRONT.
&&
.HYDROLOGY...
NO SIGNIFICANT WIDESPREAD PRECIP EXPECTED TUESDAY THROUGH THE END
OF THE WEEK.
&&
.EQUIPMENT...
THE NEW YORK CITY NOAA ALL HAZARDS WEATHER RADIO STATION KWO35 IS
OUT OF SERVICE.
DUE TO INTERFERENCE ISSUES WITH THE U.S. COAST GUARD EMERGENCY
BROADCAST CHANNEL...THE NEW YORK CITY NOAA ALL HAZARDS WEATHER
RADIO STATION KWO35 IS OUT OF SERVICE.
DURING THE TIME...THE TRANSMITTER MAY BE RETURNED TO SERVICE
INTERMITTENTLY FOR USE OF THE NOAA ALL HAZARDS WEATHER RADIO
DURING POTENTIALLY DANGEROUS WEATHER SITUATIONS...FOR ROUTINE
WEEKLY TEST OF THE WARNING SYSTEM...AND TO DETERMINE IF THE
INTERFERENCE ISSUE HAS BEEN RESOLVED.
&&
.OKX WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
NY...NONE.
NJ...NONE.
MARINE...SMALL CRAFT ADVISORY FROM 6 PM THIS EVENING TO 6 AM EST
WEDNESDAY FOR ANZ330-335-338-340-345.
SMALL CRAFT ADVISORY UNTIL 6 AM EST WEDNESDAY FOR ANZ350-353-
355.
&&
$$
SYNOPSIS...BC/MET
NEAR TERM...TONGUE
SHORT TERM...MET
LONG TERM...BC
AVIATION...DW
MARINE...BC/MET
HYDROLOGY...BC/MET
EQUIPMENT...
AREA FORECAST DISCUSSION
NWS DODGE CITY KS
405 AM CST Tue Dec 24 2013
...Updated for long term discussion...
.SYNOPSIS...
ISSUED AT 1117 PM CST MON DEC 23 2013
At 00z Tuesday a -31c 500mb trough was located over southern
British Columbia and the Pacific Northwest. An upper level ridge
axis was located downstream of this 500mb trough, and extended
from Wyoming into southwest Manitoba. Across the Central Plains a
northwest flow was present at the 700mb and 500mb level. A 850mb
temperature gradient at 00z Tuesday was located across western
Nebraska and central Kansas. 850mb temperatures earlier this
evening ranged from -19c at Omaha and -16c at Topeka to -8c at
North Platte, -4c at Dodge City, and +2c at Amarillo. At the
surface an area of high pressure was located across eastern Kansas
and a trough of low pressure was located across eastern Colorado.
&&
.SHORT TERM...(Today and tonight)
ISSUED AT 132 AM CST TUE DEC 24 2013
A trough of low pressure at the surface will deepen along the lee
of the Rockies early today as an upper level trough, which was
located over the Pacific Northwest at 00z Tuesday, approaches the
Rockies. By late day/early evening this upper level trough will
cross the Rockies and move out into the plains. At this time given
the track of this upper trough, the 00z NAM and GFS model
soundings indicating only mid level moisture will accompany this
upper level disturbance, and given the dry layer forecast to be
present in the 850mb-700mb level the chances for precipitation
still appears small. Increasing clouds however can be expected
which may initially limit the cooling early tonight behind a cold
front that will be crossing western Kansas. Still given some
clearing behind this upper trough after midnight the lows tonight
should still fall back into the teens by early Christmas day.
Colder temperatures overnight will be over the snow pack from
roughly Larned to Minneola.
As for temperatures today, westerly downslope flow will improve
and 850mb temperatures ahead of the approaching cold front are
forecast to range from 5c to near 10c during the afternoon across
western Kansas. This continues to suggest afternoon temperatures
climbing in the lower 50s for areas that did not receive snow over
the past weekend. Will however trim a few degrees off from these
warm 850mb mix down temperatures in north central Kansas given the
increase in cloud cover late today. In areas that continue to have
snow on the ground will stay close to the previous forecast with
highs today only in the 30s.
.LONG TERM...(Wednesday through Monday)
ISSUED AT 403 AM CST TUE DEC 24 2013
The large scale pattern through Friday will be characterized by
mid to high level flow from the eastern pacific into southwest
Canada and the northern Rockies. At the surface, pressures
will generally be falling in this pattern due to the increased
low to mid level cross mountain flow, leading to fairly mild
maximum temperatures at least 1 standard deviation above average.
This means highs in the 50s, except for the areas that received
heavy snow on December 21st, which may stay 5 to 15 degrees cooler
depending on how fast the snow melts.
By Saturday through Monday, the upper level flow will amplify again,
leading to mid level flow more parallel to the Rockies and directed
over land from western Canada into the northern and central plains.
This will lead to a cold air surge at low levels into the plains,
although not as cold as some of the airmasses we have experienced
already this cold season. Highs by Sunday will fall back into the
30s, with lows falling back into the teens.
The global models that go out beyond 7 days (ECMWF, GFS and GEM)
indicate some degree of upper level troughing approaching the
plains around January 1st. The GFS is the most amplified, the ECMWF
in the middle and the GEM the weakest. Therefore, some sort of
precipitation event cannot be ruled out, and precipitation type is
also in question.
&&
.AVIATION...(For the 06Z TAFS through 06Z Tuesday night)
ISSUED AT 1117 PM CST MON DEC 23 2013
Low status and patchy freezing fog had developed earlier this
evening as a southeast wind developed. SREF and HRRR were both in
decent agreement with keeping the IFR/low MVFR status around
through at least 12z Tuesday as this south/southeasterly flow
continues. Area more favorable for the lower cigs lasting longer
early this morning will be at HYS and DDC. At GCK the winds are
forecast to veer more to the southwest between 12z and 15z
allowing for some drier air in the lower levels to advect in from
the west. In addition to the low clouds some MVFR/IFR visibilities
will also be possible, mainly in the DDC area through early
Tuesday morning. Given the low level winds from the NAM BUFR
soundings do not think widespread dense freezing fog will be an
issue at any taf site.
&&
.PRELIMINARY POINT TEMPS/POPS...
DDC 39 15 38 16 / 10 10 0 0
GCK 51 15 47 18 / 10 10 0 0
EHA 52 18 47 22 / 0 10 0 0
LBL 41 17 45 18 / 10 0 0 0
HYS 47 17 46 18 / 10 10 0 0
P28 35 16 39 15 / 10 10 0 0
&&
.DDC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...Burgert
SHORT TERM...Burgert
LONG TERM...Finch
AVIATION...Burgert
AREA FORECAST DISCUSSION
NWS DODGE CITY KS
136 AM CST Tue Dec 24 2013
...Updated short term discussion...
.SYNOPSIS...
ISSUED AT 1117 PM CST MON DEC 23 2013
At 00z Tuesday a -31c 500mb trough was located over southern
British Columbia and the Pacific Northwest. An upper level ridge
axis was located downstream of this 500mb trough, and extended
from Wyoming into southwest Manitoba. Across the Central Plains a
northwest flow was present at the 700mb and 500mb level. A 850mb
temperature gradient at 00z Tuesday was located across western
Nebraska and central Kansas. 850mb temperatures earlier this
evening ranged from -19c at Omaha and -16c at Topeka to -8c at
North Platte, -4c at Dodge City, and +2c at Amarillo. At the
surface an area of high pressure was located across eastern Kansas
and a trough of low pressure was located across eastern Colorado.
&&
.SHORT TERM...(Today and tonight)
ISSUED AT 132 AM CST TUE DEC 24 2013
A trough of low pressure at the surface will deepen along the lee
of the Rockies early today as an upper level trough, which was
located over the Pacific Northwest at 00z Tuesday, approaches the
Rockies. By late day/early evening this upper level trough will
cross the Rockies and move out into the plains. At this time given
the track of this upper trough, the 00z NAM and GFS model
soundings indicating only mid level moisture will accompany this
upper level disturbance, and given the dry layer forecast to be
present in the 850mb-700mb level the chances for precipitation
still appears small. Increasing clouds however can be expected
which may initially limit the cooling early tonight behind a cold
front that will be crossing western Kansas. Still given some
clearing behind this upper trough after midnight the lows tonight
should still fall back into the teens by early Christmas day.
Colder temperatures overnight will be over the snow pack from
roughly Larned to Minneola.
As for temperatures today, westerly downslope flow will improve
and 850mb temperatures ahead of the approaching cold front are
forecast to range from 5c to near 10c during the afternoon across
western Kansas. This continues to suggest afternoon temperatures
climbing in the lower 50s for areas that did not receive snow over
the past weekend. Will however trim a few degrees off from these
warm 850mb mix down temperatures in north central Kansas given the
increase in cloud cover late today. In areas that continue to have
snow on the ground will stay close to the previous forecast with
highs today only in the 30s.
.LONG TERM...(Tuesday night through Monday)
ISSUED AT 205 PM CST MON DEC 23 2013
Tuesday night will begin with a northwest flow aloft over western
Kansas. Some of the snowpack will remain from Sat-Sun`s snow storm,
and temperatures will show cold bias in the eastern sections of our
CWA, in the Larned, Stafford, and Pawnee counties, where 14 to 15
inches of snow fell and will slow to melt. Mostly clear skies are
anticipated through the day 5.5 forecast, with clouds moving in next
Sunday. Wednesday will see an east to west temperature gradient,
with MaxT`s ranging from around 33F degrees in St. John to 38F
degrees in Dodge City, to 47F degrees near the Colorado border.
This same temperature pattern will exist from Wednesday into
Saturday, rising to the 43F degree to 56F degree range by both
Friday and Saturday. Winds will basically be from the west or
northwest and not over the 10 to 20 mph range. At night, winds will
tend to drop off to less than 10 mph, allowing the mercury to fall
significantly. Lows on Wednesday will dip into the teens to near
12F degrees in the deepest snow between Kinsley and Larned, and
range upward to around 21F degrees near Hays and Liberal. Lows will
increase each day through Saturday and Sunday mornings, leveling off
in the mid 20s to around 30F degrees by Sat.
On Sunday, both the ECMWF and GFS models are forecasting an arctic
outbreak of cold air to plunge south through the plains and invade
central Kansas Sunday afternoon. Clouds will increase to cloudy and
probably be thick stratus. We could have another non-diurnal
temperature pattern on Sunday, with highs occurring in the mid day,
then falling in the afternoon. Since Sunday is day 7, will not put
the hourly temps in the grids, but it may be something we have to
watch as the Sunday period approaches.
&&
.AVIATION...(For the 06Z TAFS through 06Z Tuesday night)
ISSUED AT 1117 PM CST MON DEC 23 2013
Low status and patchy freezing fog had developed earlier this
evening as a southeast wind developed. SREF and HRRR were both in
decent agreement with keeping the IFR/low MVFR status around
through at least 12z Tuesday as this south/southeasterly flow
continues. Area more favorable for the lower cigs lasting longer
early this morning will be at HYS and DDC. At GCK the winds are
forecast to veer more to the southwest between 12z and 15z
allowing for some drier air in the lower levels to advect in from
the west. In addition to the low clouds some MVFR/IFR visibilities
will also be possible, mainly in the DDC area through early
Tuesday morning. Given the low level winds from the NAM BUFR
soundings do not think widespread dense freezing fog will be an
issue at any taf site.
&&
.PRELIMINARY POINT TEMPS/POPS...
DDC 39 15 38 16 / 10 10 0 0
GCK 51 15 45 18 / 10 10 0 0
EHA 52 18 47 22 / 0 10 0 0
LBL 41 17 45 18 / 10 0 0 0
HYS 47 17 44 18 / 10 10 0 0
P28 35 16 39 15 / 10 10 0 0
&&
.DDC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...Burgert
SHORT TERM...Burgert
LONG TERM...Burke
AVIATION...Burgert
AREA FORECAST DISCUSSION
NWS DODGE CITY KS
1121 PM CST Mon Dec 23 2013
...Updated synopsis and aviation discussion...
.SYNOPSIS...
ISSUED AT 1117 PM CST MON DEC 23 2013
At 00z Tuesday a -31c 500mb trough was located over southern
British Columbia and the Pacific Northwest. An upper level ridge
axis was located downstream of this 500mb trough, and extended
from Wyoming into southwest Manitoba. Across the Central Plains a
northwest flow was present at the 700mb and 500mb level. A 850mb
temperature gradient at 00z Tuesday was located across western
Nebraska and central Kansas. 850mb temperatures earlier this
evening ranged from -19c at Omaha and -16c at Topeka to -8c at
North Platte, -4c at Dodge City, and +2c at Amarillo. At the
surface an area of high pressure was located across eastern Kansas
and a trough of low pressure was located across eastern Colorado.
&&
.SHORT TERM...(This evening through Tuesday)
ISSUED AT 1234 PM CST MON DEC 23 2013
Tonight:
Low level stratus is expected to be pretty much gone by this afternoon,
however, there still will be some mid to high level clouds that will
stick around through the overnight. These clouds are ahead of a synoptic
system coming out of the northern Rockies and eventually across the
Central/Northern Plains tomorrow. Otherwise, the forecast will remain
free of precipitation through the overnight hours. Minimums will be
in the lower teens (F).
Tomorrow:
The aforementioned synoptic system will result in continuation of scattered
mid to high level clouds tomorrow. The NAM suggests potential for flurries,
but not buying into this solution, as low levels are fairly dry and
"warm". Will keep precipitation probabilities at or below 10 percent.
Kind of a moot point anyway, because flurries typically don`t measure
(0.01" or higher). Anyway, there will be a gradient of temperatures
across the forecast area of responsibility. The 23.12Z NAM breaks the
inversion across west-central Kansas and advertises upper 50sF. The
rest of the mesoscale/global models (WRF, EC, etc) suggest lower maximums.
The ongoing max temp forecast still looks on track and will continue
as is. Farther east, deep snowpack will have a meso-alpha perhaps beta
influence on temperatures with values struggling to get higher than
the freezing mark, if that.
.LONG TERM...(Tuesday night through Monday)
ISSUED AT 205 PM CST MON DEC 23 2013
Tuesday night will begin with a northwest flow aloft over western
Kansas. Some of the snowpack will remain from Sat-Sun`s snow storm,
and temperatures will show cold bias in the eastern sections of our
CWA, in the Larned, Stafford, and Pawnee counties, where 14 to 15
inches of snow fell and will slow to melt. Mostly clear skies are
anticipated through the day 5.5 forecast, with clouds moving in next
Sunday. Wednesday will see an east to west temperature gradient,
with MaxT`s ranging from around 33F degrees in St. John to 38F
degrees in Dodge City, to 47F degrees near the Colorado border.
This same temperature pattern will exist from Wednesday into
Saturday, rising to the 43F degree to 56F degree range by both
Friday and Saturday. Winds will basically be from the west or
northwest and not over the 10 to 20 mph range. At night, winds will
tend to drop off to less than 10 mph, allowing the mercury to fall
significantly. Lows on Wednesday will dip into the teens to near
12F degrees in the deepest snow between Kinsley and Larned, and
range upward to around 21F degrees near Hays and Liberal. Lows will
increase each day through Saturday and Sunday mornings, leveling off
in the mid 20s to around 30F degrees by Sat.
On Sunday, both the ECMWF and GFS models are forecasting an arctic
outbreak of cold air to plunge south through the plains and invade
central Kansas Sunday afternoon. Clouds will increase to cloudy and
probably be thick stratus. We could have another non-diurnal
temperature pattern on Sunday, with highs occurring in the mid day,
then falling in the afternoon. Since Sunday is day 7, will not put
the hourly temps in the grids, but it may be something we have to
watch as the Sunday period approaches.
&&
.AVIATION...(For the 06Z TAFS through 06Z Tuesday night)
ISSUED AT 1117 PM CST MON DEC 23 2013
Low status and patchy freezing fog had developed earlier this
evening as a southeast wind developed. SREF and HRRR were both in
decent agreement with keeping the IFR/low MVFR status around
through at least 12z Tuesday as this south/southeasterly flow
continues. Area more favorable for the lower cigs lasting longer
early this morning will be at HYS and DDC. At GCK the winds are
forecast to veer more to the southwest between 12z and 15z
allowing for some drier air in the lower levels to advect in from
the west. In addition to the low clouds some MVFR/IFR visibilities
will also be possible, mainly in the DDC area through early
Tuesday morning. Given the low level winds from the NAM BUFR
soundings do not think widespread dense freezing fog will be an
issue at any taf site.
&&
.PRELIMINARY POINT TEMPS/POPS...
DDC 11 39 16 38 / 20 10 10 0
GCK 12 49 17 45 / 10 10 10 0
EHA 15 49 19 47 / 0 0 10 0
LBL 11 45 20 45 / 20 10 0 0
HYS 11 43 20 44 / 0 10 10 0
P28 10 35 15 39 / 20 10 10 0
&&
.DDC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...Burgert
SHORT TERM...Sugden
LONG TERM...Burke
AVIATION...Burgert
AREA FORECAST DISCUSSION
NWS DODGE CITY KS
1116 PM CST Mon Dec 23 2013
...Updated synopsis and aviation discussion...
.SYNOPSIS...
ISSUED AT 1110 PM CST MON DEC 23 2013
At 00z Tuesday a -31c 500mb trough was located over southern
British Columbia and the Pacific Northwest. An upper level ridge
axis was located downstream of this 500mb trough, and extended
from Wyoming into southwest Manitoba. Across the Central Plains a
northwest flow was present at the 700mb and 500mb level. A 850mb
temperature gradient at 00z Tuesday was located across western
Nebraska and central Kansas. 850mb temperatures earlier this
evening ranged from -19c at Omaha and -16c at Topeka to -8c at
North Platte, -4c at Dodge City, and +2c at Amarillo. At the
surface an area of high pressure was located across eastern Kansas
and a trough of low pressure was located across eastern Colorado.
&&
.SHORT TERM...(This evening through Tuesday)
ISSUED AT 1234 PM CST MON DEC 23 2013
Tonight:
Low level stratus is expected to be pretty much gone by this afternoon,
however, there still will be some mid to high level clouds that will
stick around through the overnight. These clouds are ahead of a synoptic
system coming out of the northern Rockies and eventually across the
Central/Northern Plains tomorrow. Otherwise, the forecast will remain
free of precipitation through the overnight hours. Minimums will be
in the lower teens (F).
Tomorrow:
The aforementioned synoptic system will result in continuation of scattered
mid to high level clouds tomorrow. The NAM suggests potential for flurries,
but not buying into this solution, as low levels are fairly dry and
"warm". Will keep precipitation probabilities at or below 10 percent.
Kind of a moot point anyway, because flurries typically don`t measure
(0.01" or higher). Anyway, there will be a gradient of temperatures
across the forecast area of responsibility. The 23.12Z NAM breaks the
inversion across west-central Kansas and advertises upper 50sF. The
rest of the mesoscale/global models (WRF, EC, etc) suggest lower maximums.
The ongoing max temp forecast still looks on track and will continue
as is. Farther east, deep snowpack will have a meso-alpha perhaps beta
influence on temperatures with values struggling to get higher than
the freezing mark, if that.
.LONG TERM...(Tuesday night through Monday)
ISSUED AT 205 PM CST MON DEC 23 2013
Tuesday night will begin with a northwest flow aloft over western
Kansas. Some of the snowpack will remain from Sat-Sun`s snow storm,
and temperatures will show cold bias in the eastern sections of our
CWA, in the Larned, Stafford, and Pawnee counties, where 14 to 15
inches of snow fell and will slow to melt. Mostly clear skies are
anticipated through the day 5.5 forecast, with clouds moving in next
Sunday. Wednesday will see an east to west temperature gradient,
with MaxT`s ranging from around 33F degrees in St. John to 38F
degrees in Dodge City, to 47F degrees near the Colorado border.
This same temperature pattern will exist from Wednesday into
Saturday, rising to the 43F degree to 56F degree range by both
Friday and Saturday. Winds will basically be from the west or
northwest and not over the 10 to 20 mph range. At night, winds will
tend to drop off to less than 10 mph, allowing the mercury to fall
significantly. Lows on Wednesday will dip into the teens to near
12F degrees in the deepest snow between Kinsley and Larned, and
range upward to around 21F degrees near Hays and Liberal. Lows will
increase each day through Saturday and Sunday mornings, leveling off
in the mid 20s to around 30F degrees by Sat.
On Sunday, both the ECMWF and GFS models are forecasting an arctic
outbreak of cold air to plunge south through the plains and invade
central Kansas Sunday afternoon. Clouds will increase to cloudy and
probably be thick stratus. We could have another non-diurnal
temperature pattern on Sunday, with highs occurring in the mid day,
then falling in the afternoon. Since Sunday is day 7, will not put
the hourly temps in the grids, but it may be something we have to
watch as the Sunday period approaches.
&&
.AVIATION...(For the 06Z TAFS through 06Z Tuesday night)
ISSUED AT 1110 PM CST MON DEC 23 2013
Low status and areas of freezing fog had developed earlier this
evening as a southeast wind developed. SREF and HRRR were both in
decent agreement with keeping the IFR/low MVFR status around
through at least 12z Tuesday as this south/southeasterly flow continues.
Area more favorable for the lower cigs lasting longer early this
morning will be at HYS and DDC. At GCK the winds are forecast to
veer more to the southwest between 12z and 15z allowing for some drier
air in the lower levels to advect in from the west. In addition to
the low clouds some MVFR/IFR visibilities will also be possible,
mainly in the DDC area through early Tuesday morning. Given the
low level winds from the NAM BUFR soundings do not think widespread
dense fog will be an issue at any taf site.
&&
.PRELIMINARY POINT TEMPS/POPS...
DDC 11 39 16 38 / 20 10 10 0
GCK 12 49 17 45 / 10 10 10 0
EHA 15 49 19 47 / 0 0 10 0
LBL 11 45 20 45 / 20 10 0 0
HYS 11 43 20 44 / 0 10 10 0
P28 10 35 15 39 / 20 10 10 0
&&
.DDC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...Burgert
SHORT TERM...Sugden
LONG TERM...Burke
AVIATION...Burgert
AREA FORECAST DISCUSSION
NWS JACKSON KY
857 PM EST WED DEC 25 2013
.UPDATE...
ISSUED AT 857 PM EST WED DEC 25 2013
RADAR RETURNS ARE INCREASING TO OUR NORTH AND A FEW SURFACE OBS HAVE
BEEN REPORTING LIGHT SNOW UNDERNEATH RECENTLY. SURFACE DEWPOINTS
HAVE TRENDED UPWARDS IN RECENT HOURS AND ARE NOW RUNNING HIGHER THAN
THE INHERITED FORECAST SO SUSPECT THERE WILL BE A LITTLE MORE
MOISTURE FOR THIS SYSTEM TO WORK WITH THAN PREVIOUSLY THOUGHT. A
RECENT HRRR RUN ALSO BROUGHT SOME SNOW SHOWERS ALL THE WAY SOUTH TO
JKL. SO...WILL INCREASE POPS A BIT OVER OUR NORTHERN TIER AND
MENTION A DUSTING POSSIBLE IN THE HWO...ALTHOUGH WITH TEMPS ABOVE
FREEZING...MINIMAL IMPACTS ARE EXPECTED.
UPDATE ISSUED AT 643 PM EST WED DEC 25 2013
WILL TWEAK THE TEMP CURVE A BIT TONIGHT AS EASTERN VALLEYS HAVE
ALREADY FALLEN BELOW FREEZING...WITH A FEW SPOTS ALREADY IN THE 20S.
I SUSPECT WE WILL EXPERIENCE OUR LOWS IN THESE VALLEYS THIS EVENING
WITH TEMPS LEVELING OFF OR EVEN RISING SEVERAL DEGREES LATER THIS
EVENING AS MID LEVEL CLOUDS MOVE OVERHEAD FROM THE WEST.
OTHERWISE...WATCHING A BAND OF WEAK RETURNS ON RADAR UP NEAR CINCY.
NO SURFACE REPORTS OF ANYTHING REACHING THE GROUND FROM THIS BUT NAM
TIME HEIGHTS SHOW LOW LEVELS MOISTENING UP ENOUGH TO JUSTIFY CURRENT
MENTION OF FLURRIES/ISOLATED SNOW SHOWERS OVER OUR NORTHERN COUNTIES
LATER TONIGHT.
&&
.SHORT TERM...(THIS EVENING THROUGH THURSDAY NIGHT)
ISSUED AT 246 PM EST WED DEC 25 2013
TEMPERATURES REBOUNDED WELL THROUGH THE DAY CLIMBING BACK INTO THE
LOWER 40S ACROSS SOUTHERN PORTIONS OF OUR CWA...MID 30S TO NEAR 40
ELSEWHERE UNDER STRONG SUNSHINE...CLEAR SKIES AND A LIGHT SOUTHERLY
RETURN FLOW.
MODELS ARE IN GOOD AGREEMENT THROUGH THE SHORT TERM PERIOD. SHORT
WAVE TROUGH WILL SWEEP ACROSS THE GREAT LAKES...OHIO VALLEY BETWEEN
NOW AND THURSDAY EVENING. CORRESPONDING SURFACE COLD FRONTAL BOUNDARY
WILL MOVE THROUGH EASTERN KENTUCKY BY EARLY THURSDAY MORNING...JUST
AFTER SUNRISE. FRONTAL FEATURES BECOME LESS DISTINCT WITH TIME. BUT
THERE WILL BE ENOUGH CLOUD COVER ASSOCIATED WITH THIS SYSTEM TO MAKE
THE OVERNIGHT LOW TEMPERATURE FORECAST MORE CHALLENGING THAN MIGHT
OTHERWISE BE. WITH DRY AIR IN PLACE DROPPED EVENING TEMPERATURES DOWN
PRETTY QUICKLY...ESPECIALLY IN OUR TYPICALLY COOLER EASTERN VALLEY
LOCATIONS. BUT TEMPERATURES SHOULD REBOUND AS CLOUDS ROLL INTO THE
AREA LATER TONIGHT. SKIES SHOULD ONCE AGAIN BEGIN TO CLEAR OUT
TOWARDS DAWN. WITH SOME WEAK CAA KICKING IN AND SKIES PARTIALLY
CLEARING TEMPS MAY DROP BACK DOWN FOR A FEW HOURS AGAIN EARLY
THURSDAY MORNING. NOT EXPECTING MUCH IN THE WAY OF PRECIPITATION WITH
THIS WEAK SYSTEM. ATTM CAN NOT RULE OUT SOME ISOLD SNOW SHOWER
ACTIVITY ALONG AND NORTH OF INTERSTATE 64 AND SOME FLURRIES IN OUR
EASTERN MOST COUNTIES. TEMPERATURE REBOUND NICELY AGAIN THURSDAY BUT
SHOULD BE JUST A COUPLE DEGREES COOLER THAN TODAY.
.LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 246 PM EST WED DEC 25 2013
AT THE START OF THE LONG TERM PORTION OF THE FORECAST THE UPPER
LEVEL FLOW WILL BE RELAXING WITH RISING HEIGHTS ACROSS OUR REGION.
THE NORTHERN STREAM WILL BECOME MORE ZONAL AS WE MOVE INTO THE
WEEKEND WHILE IN THE SOUTHERN STREAM A SHORT WAVE TROUGH WILL MOVE
INTO THE SOUTHERN PLAINS. AT THE SAME TIME THE CENTER OF SURFACE
HIGH PRESSURE WILL BE MOVING OFF TO OUR EAST. THIS ALL SPELLS
MODERATING TEMPERATURES AS WE MOVE INTO THE WEEKEND. YESTERDAY IT
APPEARED THAT THE SOUTHERN STREAM SYSTEM THAT MOVES INTO THE SE U.S.
THIS WEEKEND WOULD REMAIN TOO FAR SOUTH TO HAVE AN IMPACT ON OUR
LOCAL WEATHER. HOWEVER...THE 06Z AND 12Z GFS POINT TOWARDS A
PRECIPITATION CHANCE OVER AT LEAST THE SOUTHEAST PART OF THE
FORECAST AREA FROM SATURDAY NIGHT INTO SUNDAY. THIS IDEA IS
SUPPORTED BY THE 12Z ECMWF AS WELL. THE STANDARD BLENDED LOAD
PROVIDED SLIGHT CHANCE PRECIPITATION CHANCES FOR SATURDAY NIGHT IN
THE SOUTH AND CENTRAL PARTS OF THE FORECAST AREA...WITH A SLIGHT
CHANCE OVER THE CENTRAL AND EAST ON SUNDAY. WILL FOLLOW THIS IDEA.
MOST...IF NOT ALL OF ANY PRECIPITATION SHOULD BE IN THE FORM OF RAIN
SATURDAY NIGHT INTO SUNDAY...AND FOR NOW HAVE CARRIED ONLY RAIN IN THE
FORECAST. HOWEVER THERE IS AN OUTSIDE CHANCE THAT SOME VERY LIGHT
FROZEN PRECIPITATION...POSSIBLY SLEET...COULD OCCUR FOR A VERY BRIEF
PERIOD OF TIME AT PRECIPITATION ONSET LATE SATURDAY NIGHT.
THERE IS STILL GENERAL MODEL AGREEMENT WITH THE UPPER LEVEL TROUGH
DEEPENING ACROSS EASTERN NORTH AMERICA ONCE AGAIN AS WE MOVE INTO
THE EARLY PART OF NEXT WEEK. A COLD FRONT IS FORECAST TO MOVE ACROSS
THE AREA LATE SUNDAY...WITH A SLIGHT CHANCE FOR LIGHT RAIN AND SNOW
SUNDAY NIGHT AND A SLIGHT CHANCE FOR LIGHT SNOW ON MONDAY IN THE
SOUTHEAST. COLD BUT DRY CONDITIONS WILL THEN PERSIST INTO NEW YEARS
DAY.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z THURSDAY EVENING)
ISSUED AT 643 PM EST WED DEC 25 2013
EXPECT VFR CONDITIONS THROUGH THE FORECAST PERIOD. HOWEVER...TAF
SITES SHOULD SEE SOME CLOUD COVER TONIGHT AS A FRONTAL BOUNDARY
SLIDES THROUGH THE AREA. LOWEST POTENTIAL CIGS WILL BE AROUND 5K FT
NORTH OF KJKL. CANNOT RULE OUT A FEW SNOW SHOWERS...GENERALLY ALONG
AND NORTH OF I64. ANY ACTIVITY SHOULD BE TOO FAR NORTH TO AFFECT
KSJS OR KJKL THOUGH. WINDS WILL BE SOUTHWESTERLY BUT VEERING TO THE
WEST...NORTHWEST THURSDAY AT AROUND 5 KTS BEHIND THE FRONTAL
BOUNDARY.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...ABE
SHORT TERM...RAY
LONG TERM...SBH
AVIATION...ABE
AREA FORECAST DISCUSSION
NWS CARIBOU ME
1213 AM EST TUE DEC 24 2013
.SYNOPSIS...
WEAK LOW PRESSURE WILL MOVE EAST INTO THE MARITIMES OVERNIGHT. COLD
HIGH PRESSURE WILL THEN MOVE IN TUESDAY AND WEDNESDAY.
&&
.NEAR TERM /THROUGH TUESDAY/...
UPDATE...IT LOOKS LIKE FREEZING PRECIP HAS GONE OVER TO SOME LIGHT
SNOW ACROSS THE INTERIOR DOWNEAST WHILE THE COAST STILL SHOWED
SOME LIGHT FREEZING DRIZZLE OR PLAIN RAIN MIXING W/SNOW. THIS IS
MOST EVIDENT FROM THE LAPS SOUNDINGS SHOWING THAT DRY WEDGE IN THE
MID LEVELS AND DEEP MOISTURE IN THE LLVLS. LAST 3HR TRENDS FROM
THE OBS IN BAR HARBOR SHOW JUST RAIN W/TEMPERATURES AROUND 34F. ANY
FREEZING PRECIP SHOULD MOVE E AN END BY 3 AM. ADJUSTED THE PRECIP
CHANCES TOWARD MORNING DOWN TO 20-30% USING THE HRRR GUIDANCE AS
THE HRRR INDICATED PRECIP SHIELD PULLING OFF THE COAST AND TO THE
E.
COLDER AIR WITH CLRG TO PRTL CLRG SKIES ARE SLATED FOR THE FA
LATE TNGT WITH INCREASING NW WINDS. A SIG NW BREEZE IS LIKELY TO
CONT ON TUE...WITH POTENTIAL IMPLICATIONS FOR FURTHER DAMAGE IN
THE MAX ICE ACCRETION ZONE DOWNEAST IN THE ABSENCE OF ANNY
MELTING...WHICH DOES NOT APPEAR LIKELY N OF THE IMMEDIATE COAST.
DUE TO MDTLY STRONG LLVL COLD ADVCN ON TUE...HI TEMPS TUE WILL
ONLY RECOVER A FEW DEGREES AT BEST FROM OVRNGT LOWS UNDER MSLY CLR
TO PTLY CLDY SKIES.
&&
.SHORT TERM /TONIGHT THROUGH THURSDAY/...
ARCTIC HIGH PRESSURE BUILDS INTO NEW ENGLAND FOR A BITTERLY COLD
CHRISTMAS DAY. A WIND CHILL ADVISORY MAY BE NECESSARY LATE TUESDAY
NIGHT INTO CHRISTMAS DAY MORNING.
AFTER ANOTHER CHILLY NIGHT...TEMPERATURES WARM SIGNIFICANTLY ON
THURSDAY AHEAD OF A CLIPPER SYSTEM. LIGHT SNOW SHOULD DEVELOP IN
THE AFTERNOON AS THIS SYSTEM APPROACHES.
&&
.LONG TERM /THURSDAY NIGHT THROUGH MONDAY/...
A CLIPPER SYSTEM MOVES ACROSS THE GULF OF MAINE AND INTO THE
MARITIMES THURSDAY NIGHT INTO EARLY FRIDAY. A COUPLE INCHES OF
SNOWFALL WILL BE POSSIBLE WITH THE PASSAGE OF THIS
SYSTEM...ESPECIALLY NEAR THE NEW BRUNSWICK BORDER.
MORE ARCTIC AIR SPILLS INTO THE REGION BEHIND THIS SYSTEM. THE GFS
AND ECMWF DIFFER ON YET ANOTHER LOW PRESSURE SYSTEM FORECAST TO
APPROACH NORTHERN NEW ENGLAND ON SUNDAY. THE ECMWF IS FARTHER SOUTH
WITH THE TRAJECTORY OF THIS SYSTEM WHICH RESULTS IN HIGHER
QPF/SNOWFALL AMOUNTS.
&&
.AVIATION /05Z TUESDAY THROUGH SATURDAY/...
NEAR TERM: CONDITIONS AT THE TERMINALS ACROSS NORTHERN AND EASTERN
MAINE VARY CONSIDERABLY LATE THIS EVENING FROM IFR TO VFR. PATCHES
OF LOWER STRATUS WILL MOVE IN AND OUT MAKING THE CEILING FORECAST
A CHALLENGE AND WILL LIKELY BE HIGHLY VARIABLE OVER THE NEXT
SEVERAL HOURS. CONDITIONS SHOULD IMPROVE TO VFR BY DAYBREAK TUE
ACROSS ALL TAF SITES...WITH VFR CONTG THRU THE DAY TUE. A PERIOD
OF MVFR POSSIBLE AT THE NORTHERN TERMINALS TUE EVENING IN SNOW
SHOWERS.
SHORT TERM: IFR CIGS AND VSBYS WILL BE POSSIBLE LATE THURSDAY
THROUGH EARLY FRIDAY DUE TO SNOW AND FOG. OTHERWISE VFR CONDITIONS
ARE EXPECTED.
&&
.MARINE...
NEAR TERM: SEAS RUNNING AROUND 5 FT AT THE EASTERN MAINE SHELF
LATE THIS EVENING AND WILL CONT WITH SCA FOR HAZ SEAS FOR THE OUTER
WATERS INTO TUE AFTN BASED ON BLENDED FCST WW3/SWAN NAM/SWAN GFS
WV HTS WHICH ALSO HAD TO BE ADJUSTED UPWARDS BY 1 TO 2 FT THRU
TNGT GIVEN THE LATEST LOW BIAS COMPARED TO BUOY OBS.
SHORT TERM: AN SCA MAY BE NEEDED ON CHRISTMAS DAY FOR WIND GUSTS
IN EXCESS OF 25 KNOTS AND FOR WAVE HEIGHTS 5-7 FEET THURSDAY
AFTERNOON AND EVENING.
&&
.CAR WATCHES/WARNINGS/ADVISORIES...
ME...NONE.
MARINE...SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS UNTIL 4 PM EST THIS
AFTERNOON FOR ANZ050-051.
&&
$$
NEAR TERM...HEWITT
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
619 PM EST WED DEC 25 2013
.SHORT TERM...(THIS EVENING THROUGH THURSDAY)
ISSUED AT 446 PM EST WED DEC 25 2013
12Z RAOBS/LATEST WV IMAGERY AND RUC ANALYSIS SHOW UPR TROF CENTERED
OVER CENTRAL NAMERICA BTWN RDGING OVER THE ERN CONUS EXTENDING INTO
QUEBEC AND A STRONGER MEAN RDG OVER THE W. VERY CHILLY AIR LINGERS
OVER THE UPR LKS WITH H85 TEMPS IN THE -15C TO -20C RANGE. THERE ARE
SEVERAL SHRTWVS OF INTEREST EMBEDDED WITHIN THIS UPR TROF. THE FIRST
IS MOVING INTO WRN UPR MI EARLY THIS AFTN AND ACCOMPANIED BY AN AREA
OF COLDER CLD TOPS SHOWN ON IR STLT IMAGERY. IN CONCERT WITH SOME
DEEPER MSTR TO H5 SHOWN ON THE 12Z INL RAOB...SCT-NMRS -SHSN
IMPACTED MUCH OF THE CWA INTO EARLY THIS AFTN BEFORE LARGER SCALE
FORCING ASSOCIATED WITH THE SHRTWV THAT CAUSED THE SN LAST NGT/THIS
MRNG EXITED THE AREA. BUT LARGER SCALE QVECTOR DVGC HAS WEAKENED
THIS SHRTWV/WARMED CLD TOP TEMPS...DIMINISHING THE SHSN DURING THE
LAST COUPLE OF HRS. IN FACT...THERE HAS BEEN SOME CLRG THIS AFTN. A
SECOND SHRTWV IS DIGGING SSEWD THRU MANITOBA...ACCOMPANIED BY A
120KT H3 JET MAX. YET ANOTHER SHRTWV RIDING OVER THE TOP OF THE WRN
RDG IS PUSHING INTO BRITISH COLUMBIA.
MAIN FCST CONCERNS IN THE SHORT TERM ARE POPS/SN AMNTS/NEED FOR
HEADLINES ASSOCIATED WITH PARADE OF SHRTWS PASSING THRU THE UPR LKS
WITHIN THE PERSISTENT UPR TROF.
TNGT...AS SHRTWV DIGGING SEWD THRU MANITOBA PASSES INTO WI
TNGT...EXPECT A WSHFT TO THE NW TO DRIVE A LO PRES TROF ONSHORE.
ALTHOUGH THE 12Z NAM/GFS SHOW THE SHARPEST DPVA/H7-3 QVECTOR CNVGC
PASSING TO THE SW OF THE CWA CLOSER TO THE ACCOMPANYING H3 JET
CORE...NAM FCST SDNGS SHOW INVRN BASE AT CMX RISING TO NEAR 7K FT
THIS EVNG IN THE PRESENCE OF DEEPER MSTR. WITH VERY COLD LLVL AIR
LINGERING NEAR THE SFC...THE SFC WSHFT FM THE WSW OVER THE INTERIOR
WL NOT BE AS DRAMATIC AS OVER/NEAR LK SUP. THE RESULT WL BE
SHARPENED LAND BREEZE LLVL CNVGC NEAR LK SUP...FIRST OVER THE NW CWA
THIS EVNG AND THEN ALSO OVER THE FAR ERN CWA LATER. SINCE THE
ACCOMPANYING UVV IS CENTERED WITHIN THE DGZ AS SHOWN ON NAM FCST
SDNGS...SN/WATER RATIOS SHOULD BE AS HI AS 25-30:1. RELATIVELY LGT
WINDS NO HIER THAN 10-15 KTS SHOULD RESULT IN MINIMAL FRACTURING OF
THE SN FLAKES. CONSIDERING THE FRBL SN/WATER RATIOS AND POTENTIAL
FOR ENHANCED SN NEAR LAND BREEZE CNVGC ZONES...OPTED TO ISSUE AN LES
ADVY FOR THE KEWEENAW AND ALGER/LUCE COUNTIES FOR MAINLY THE AREAS
NEAR LK SUP E FM GRAND MARAIS TO CRISP POINT. ALSO CONCERNED AT
LEAST NORTHERN ONTONAGON COUNTY COULD SEE SOME HEAVIER SN TNGT...
BUT OPTED NOT TO INCLUDE THAT ZONE IN THE HEADLINE SINCE HEAVIER SN
IS LIKELY TO IMPACT ONLY THE RELATIVELY UNPOPULATED NRN PORTION OF
THIS COUNTY. SINCE THERE HAS BEEN PARTIAL CLRG OVER MUCH OF THE CWA
LATE THIS AFTN...OPTED TO LOWER MIN TEMPS A BIT WITH THE EXPECTATION
TEMPS COULD FALL QUICKLY BEFORE A WSHFT TOWARD THE NW ABV THE
SHALLOW COLD AIR NEAR THE SFC BRINGS IN MORE CLDS. BACKING LLVL FLOW
LATE AHEAD OF APRCHG HI PRES RDG/SHRTWV RDG FOLLOWING THE DEPARTING
DIGGING SHRTWV MAY BRING SOME PARTIAL CLRG/MORE UNMODIFIED ARCTIC
AIR TO THE INTERIOR W NEAR THE WI BORDER AS WELL.
THU...NEXT SHRTWV NOW TOPPING UPR RDG OVER WRN CANADA IS PROGGED TO
DIG SEWD THRU MN IN PERSISTENT NW FLOW ALF...WITH SHARPEST DEEP LYR
QVECTOR CNVGC PASSING TO THE SW OF UPR MI. LLVL WINDS ARE FCST TO
BACK SLOWLY TOWARD THE WSW OVER MAINLY THE WRN CWA THRU THE DAY
AHEAD OF THIS DISTURBANCE...SO LES SHOULD BECOME CONFINED TO MAINLY
THE KEWEENAW. ALTHOUGH SN TOTALS OVER KEWEENAW COUNTY TNGT MAY NOT
BE AS IMPRESSIVE AS IN HOUGHTON COUNTY...THE NRN PORTION OF THE
KEWEENAW WL LIKELY SEE MORE SN ON THU...ESPECIALLY LATER IN THE DAY.
WITH A MORE 300 DEGREE FLOW LINGERING THRU MUCH OF THE DAY TO THE
E...EXPECT THE MOST WDSPRD AND HEAVIER LES TO IMPACT ERN ALGER AND
THE THE N HALF OF LUCE COUNTY. OVER THE SCENTRAL...ARRIVAL OF HI
PRES RDG AHEAD OF THE SHRTWV WL BRING PARTIAL SUNSHINE FILTERED BY
MID/HI CLDS ASSOCIATED WITH THE MSTR STARVED SHRTWV.
.LONG TERM...(THURSDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 446 PM EST WED DEC 25 2013
THURSDAY NIGHT...WITH PASSAGE OF SFC RIDGE...LINGERING LES WILL END
AS WINDS SHIFT SW/OFFSHORE. EXPECT LES WITH THE STRONGER LOW LEVEL CONV
OVER THE FAR NORTHEAST CWA...PER HIGH RES MODELS...COULD STILL
PRODUCE A FEW MORE INCHES OF SNOW. HOWEVER...THE SNOW OVER THE
KEWEENAW SHOULD GENERALLY BE LIGHT...WITH AN INCH OR LESS.
FRIDAY INTO FRI NIGHT...WAA WILL DOMINATE WITH A TEMPORARY
TRANSITION TOWARD A MORE ZONAL PATTERN. THERE MAY BE PERIOD OF LIGHT
PCPN ASSOCIATED WITH ISENTROPIC LIFT THROUGH THE 850-700 MB FRONTAL
ZONE. THE DEEPEST MOISTURE AND BEST CHANCE FOR SATURATION WITH
MEASURABLE PCPN IS EXPECTED FROM THE KEWEENAW INTO THE NE CWA. THERE
MAY BE ENOUGH OF A WARM LAYER...PER NAM/GFS...FOR SOME LIGHT MIXED
PCPN. HOWEVER GIVEN MODEL DIFFERENCES COMAPRED TO THE COLDER
ECMWF...CONFIDENCE WAS NOT HIGH ENOUGH TO INCLUDE ANY SLEET OR FREEZING
RAIN AT THIS TIME.
SAT THROUGH SAT NIGHT...WARMING WILL CONTINUE AHEAD OF A SHRTWV
TRACKING FROM BC NW TO THE NRN PLAINS. MOST LOCATIONS SHOULD CLIMB
TO NEAR 30. HOWEVER...A COLD FRONT DRIFTING SOUTH ACROSS THE CWA MAY
INFLUENCE MAX TEMPS DEPENING ON HOW QUICKLY IT MOVES N-S THROUGH THE
AREA FROM THE LATE MORNING THROUGH THE AFTERNOON. MODEL DIFFERENCES
REMAIN REGARDING THE STRENGTH/TIMING OF THE SHRTWV AND SFC TROUGH
DEVELOPMENT TO THE SOUTH. AFTER THE ARCTIC COLD FRONT MOVES THROUGH
WITH 850 MB TEMPS DROPPING TO AROUND -18C BY 12Z/SUN...LAKE ENHANCED
TO LES WILL DEVELOP. A PERIOD OF MODERATE TO EVEN HEAVY SNOW MAY BE
POSSIBLE FOR NORTH FLOW FAVORED SNOWBELTS IF THE STRONGER
SHRTWV/TROUGH DEVELOPS.
SUN-WED...AFTER WINDS GRADUALLY BACK ON SUN AS HIGH PRES BUILDS
TOWARD THE AREA...PERSISTENT LES WILL THEN DEVELOP FROM SUN THROUGH
TUE...MOSTLY FOR W TO WNW WIND FAVORED SNOWBELTS...AS ACRTIC AIR
SETTLES OVER THE AREA WITH 850 MB TEMPS TO AROUND -25C. BY WED THERE
IS MORE UNCERTAINTY WITH THE WIND DIRECTION GIVEN THE POTENTIAL FOR
CLIPPER SHRTWVS(ECMWF) THAT MAY BRING BACKING WINDS.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z THURSDAY EVENING)
ISSUED AT 619 PM EST WED DEC 25 2013
CMX...EXPECT PREDOMINANT IFR/LIFR CONDITIONS THROUGH THE PERIOD WITH
LAKE EFFECT SNOW SHOWERS.
IWD...IFR VSBYS WILL CONTINUE THIS EVENING WITH THE APRCH/PASSAGE OF
A LO PRES TROF. FOLLOWING THE EXIT OF THIS TROF LATER
TNGT...CONDITIONS WL IMPROVE TO MVFR AND THEN TO VFR ON THU WITH THE
APRCH OF A HI PRES RDG/ BACKING LLVL FLOW.
SAW...EXPECT VFR CONDITIONS THIS EVENING TO GIVE WAY TO A PERIOD OF
MVFR CIGS TNGT ASSOCIATED WITH A LO PRES TROF PASSAGE. VFR WX SHOULD
THEN FOLLOW LATE TNGT INTO THU WITH A DOWNSLOPE W WIND FOLLOWING THE
TROF.
&&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 446 PM EST WED DEC 25 2013
EXPECT W TO NW WINDS UP TO 25 KTS TONIGHT TO DIMINISH TO UNDER 20
KTS ON THU WITH APPROACH OF A HI PRES RIDGE/WEAKER PRES GRADIENT.
FOLLOWING THE PASSAGE OF AN ARCTIC COLD FRONT...NORTH GALES ARE
POSSIBLE. HEAVY FREEZING SPRAY IS ALSO EXPECTED FROM SATURDAY NIGHT
INTO TUESDAY.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
LAKE EFFECT SNOW ADVISORY FROM 1 AM TO 7 PM EST THURSDAY FOR
MIZ006-007.
LAKE EFFECT SNOW ADVISORY UNTIL 7 PM EST THURSDAY FOR MIZ001-003.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...KC
LONG TERM...JLB
AVIATION...07
MARINE...KC
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
440 PM EST TUE DEC 24 2013
.SHORT TERM...(THIS EVENING THROUGH WEDNESDAY)
ISSUED AT 438 PM EST TUE DEC 24 2013
12Z RAOBS/LATEST WV IMAGERY AND RUC ANALYSIS SHOWS SHRTWV RDG AXIS
MOVING INTO THE WRN LKS BTWN DEPARTING TROF IN THE SE GRT LKS
RESPONSIBLE FOR LES THE PAST FEW DAYS AND A PAIR OF SHRTWVS DIGGING
SEWD THRU SCENTRAL CANADA/THE NRN ROCKIES E OF MEAN RDG NEAR THE W
COAST. WITH SFC HI PRES BLDG ACRS THE AREA...LINGERING LES NEAR LK
SUP HAS DIMINISHED AND PUSHED INTO THE OPEN WATERS AS THE FLOW IS
SHIFTING TO THE SSW IN ADVANCE OF THE SFC LO PRES TROF IN THE NRN
PLAINS ASSOCIATED WITH THE TWO CLIPPER SHRTWVS. THE 12Z INL/MPX
RAOBS SHOWED A VERY DRY AIRMASS WITH PWATS UNDER 0.10 INCH...SO
SKIES ARE TURNING MOSUNNY AT MOST PLACES AS THE SSW FLOW SHIFTS
LINGERING LO CLDS BACK OUT OVER LK SUP. MID CLDS IN ADVANCE OF
APRCHG CLIPPER SHRTWVS/SFC TROF ARE PUSHING EWD THRU MN...WITH SN
FALLING OVER NW MN AND THE ERN DAKOTAS. ALTHOUGH THIS SN HAS BEEN
MDT AT SOME PLACES UNDER THE SHARPER H85-5 QVECTOR CVNGC...THE
COVERAGE APPEARS TO BE LIMITED BY ABSENCE OF SGNFT MSTR INFLOW.
MAIN FCST CONCERNS IN THE SHORT TERM ARE EXPECTED POPS/SN AMOUNTS
LATE TNGT AND XMAS MRNG ASSOCIATED WITH UPSTREAM CLIPPER SHRTWVS AND
GOING WINTER STORM WATCH OVER THE ERN CWA/NEED FOR ANY NEW HEADLINES.
TNGT INTO XMAS DAY...UPR TROF TO THE NW IS FCST TO SHIFT TO THE SE
AND STRETCH FM NW ONTARIO THRU MN AND INTO THE CENTRAL PLAINS BY 12Z
WED. MODELS SHOW PCPN IN ADVANCE OF THIS TROF ARRIVING OVER THE WRN
CWA LATE THIS EVNG AND PUSHING TO THE E...WITH A 6-9 PERIOD OF SN AT
MOST LOCATIONS BEFORE THE SN DIMINISHES OVER THE W 09-12Z WED AND BY
ABOUT 18Z WED OVER THE ERN CWA FOLLOWING DEPARTURE OF DEEP LYR
QVECTOR CNVGC. MAIN NEGATIVES FOR SGNFT SN FALL INCLUDE FCST SHARPER
H85-5 QVECTOR CNVGC/SHARPER H7 UVV ASSOCIATED WITH INCOMING OUT OF
PHASE SHRTWVS FOCUSING TO THE S OF UPR MI... LACK OF SGNFT MSTR
INFLOW WITH ONLY ABOUT 1.5-2 G/KG SPECIFIC HUMIDITY NEAR H7...AND
LIMITED RESIDENCE OF TIME OF PCPN. ONE FACTOR IN FAVOR OF SOMEWHAT
HIER SN AMOUNTS IS FCST DEEP DGZ THAT MAY BOOST SN/WATER RATIOS AS
HI AS 20-25:1. CONSIDERING MODEL QPF 0.05-0.15 INCH...EXPECT 1 TO 3
INCHES OF SN. THE ONE EXCEPTION WL BE OVER THE ERN CWA DOWNWIND OF
LK MI...WHERE INCRSG SSW FLOW UP THE LENGTH OF LK MI IN THE PRESENCE
OF DEEP MSTR/H85 TEMPS ARND -15C WL BRING A PERIOD OF HEAVIER LK
ENHANCED SN. PRESENCE OF LINGERING BAND IN NRN LK MI AS SHOWN ON
RECENT STLT IMAGERY EARLY THIS AFTN INCREASES CONFIDENCE IN THIS
FCST. BULK OF HIER RES MODELS SHOW THE HEAVIER LES BAND IMPACTING
FAR SE SCHOOLCRAFT COUNTY/SRN LUCE COUNTY IN THE 09Z-15Z WED TIME
FRAME. WITH MODEL QPF RANGING FM 0.25 INCH TO AS MUCH AS 0.40 INCH
AND DEEP DGZ SHOWN ON THE FCST SDNGS...EXPECT AT LEAST A HI END ADVY
SNFALL IN THIS AREA. FCST SDNGS ALSO SHOW A PERIOD OF NEARLY
UNIDIRECTIONAL SSW FLOW WITHIN THE MIXED LYR FOR A FEW HRS DURING
TIME OF PEAK SN INTENSITY. GIVEN THESE FVRBL CONDITIONS...OPTED TO
UPGRADE WATCH TO A WRNG FOR LUCE COUNTY...WHERE HEAVIER LES BAND IS
MOST LIKELY TO RESIDE THE LONGEST AND DROP UP TO 9 TO PERHAPS 10
INCHES ALONG M-28 E OF ERY. WENT WITH AN ADVY FOR SCHOOLCRAFT COUNTY
WITH POTENTIAL FOR SOME LK ENHANCEMENT...ESPECIALLY E OF SENEY AND
MANISTIQUE. AS FOR TEMPS...ARRIVAL OF THICKER CLDS/STEADY S WIND WL
ALLOW FOR ONLY A RELATIVELY SMALL TEMP DIP EARLY OVER THE W HALF.
BUT TO THE E...EXPECT TEMPS TO FALL QUICKLY OVER THE INTERIOR ERN
CWA THIS EVNG BEFORE THE CLDS AND STEADY S WINDS ARRIVE LATER.
LATER ON XMAS DAY...AS THE UPR TROF AND SFC REFLECTION SHIFT SLOWLY
THRU THE UPR GREAT LKS...THE LLVL FLOW IS PROGGED TO VEER TOWARD THE
W. THIS WSHFT TO A MORE WSW DIRECTION WL END THE THREAT OF LK
ENHANCED SHSN OVER THE E BY EARLY AFTN BUT CAUSE SOME LES TO DVLP
OVER THE W IN THE AFTN AS H85 TEMPS DIP BACK NEAR -18C BY 00Z THU.
.LONG TERM...(WEDNESDAY NIGHT THROUGH TUESDAY)
ISSUED AT 438 PM EST TUE DEC 24 2013
WEDNESDAY NIGHT...LOW LEVEL CONV ALONG A COLD FRONT AND 850
MB TEMPS DROPPING FROM -15C TO -19C WILL BRING AN INCREASE IN LES
INTO NORTHWEST UPPER MICHIGAN WED EVENING AND OVER ERN CWA
OVERNIGHT. EVEN WITH A FAVORABLE PLACEMENT OF THE DGZ IN THE
CONVECTIVE LAYER GIVING SLR VALUES NEAR 25/1...INVERSION HEIGHTS
NEAR 6K FT AND STEADILY VEERING WINDS SHOULD KEEP ACCUMULATIONS IN
THE 2 TO 4 INCH RANGE...WITH THE GREATEST AMOUNTS IN THE HIGHER
TERRAIN FROM CALUMET TO TWIN LAKES AND NORTH OF M-28 EAST OF
MUNISING.
THU INTO THU NIGHT...NW FLOW LES WILL GRADUALLY DIMINISH AS A WEAK
SFC RIDGE BUILDS FROM THE UPPER MS VALLEY INTO THE WRN LAKES
BRINGING BACKING WINDS AND LOWERING INVERSION HEIGHTS. THE STRONGEST
FORCING AND MOST FAVORABLE WAA/ISENTROPIC LIFT ASSOCIATED WITH A
WEAK CLIPPER SHORTWAVE TROUGH IS EXPECTED TO REMAIN SOUTH OF THE
UPPER MICHIGAN.
FRI...THE ECMWF WAS MORE AGGRESSIVE WITH POTENTIAL FOR SOME LIGHT
SNOW BY LATE FRI WITH THE WAA/ISENTROPIC LIFT PATTERN DEVELOPING
AHEAD OF THE NEXT CLIPPER SHRTWV AND SFC LOW MOVING TOWARD NW
ONTARIO COMPARED TO THE GFS/GEM. WITH LOW CONFIDENCE IN ANY
PCPN...ONLY SLIGHT/CHANCE POPS WERE INCLUDED...MAINLY OVER THE EAST.
SAT INTO SAT NIGHT...A BRIEF WARMUP IS EXPECTED SATURDAY AS UPPER MI
WILL BE IN THE WARMER SECTOR AHEAD OF THE NEXT LOW. TEMPS SHOULD
CLIMB ABOVE NORMAL WITH HIGHS AROUND 30. MODEL DIFFERENCES WERE EVEN
GREATER BY SATURDAY NIGHT...AS THE ECMWF WAS SLOWER/DEEPER WITH
SHRTWV AND SFC LOW MOVING THROUGH THE NRN GREAT LAKES. REGARDLESS OF
MODEL DIFFERENCES...A COLD FRONT MOVING THROUGH WITH WINDS VEERING
SHARPLY TO THE NNW SHOULD BRING LES OR LAKE ENHANCED SNOW INTO NRN
UPPER SAT NIGHT.
SUN-TUE...ANOTHER VERY COLD ARCTIC AIRMASS WILL DOMINATE THE REGION
THROUGH THE PERIOD WITH LES EXPECTED FOR NW WIND FAVORED SNOWBELTS.
WIND CHILL VALUES NEAR ADVISORY WILL BE POSSIBLE OVER THE WEST HALF
BOTH EARLY MONDAY AND TUESDAY.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z WEDNESDAY AFTERNOON)
ISSUED AT 1231 PM EST TUE DEC 24 2013
AS THE PRES GRADIENT OVER UPR MI TIGHTENS BTWN A DEPARTING SFC HI
PRES RDG AND AN APRCHG LO PRES TROF...EXPECT GUSTY S WINDS TO DVLP
LATE THIS AFTN/EVNG AT THE MORE EXPOSED IWD/SAW LOCATIONS. OTRW...
VFR CONDITIONS WL GIVE WAY TO MVFR AND PERHAPS IFR CONDITIONS BY
LATE EVNG AS SN IN ADVANCE OF THE TROF MOVES W-E INTO UPR MI. THE
BEST CHC FOR THE IFR VSBYS WL BE AT SAW...WHERE THE LLVL S WIND WL
NOT DOWNSLOPE. EVEN AFTER THE SN DIMINISHES W-E BY SUNRISE ON WED...
MVFR SC CIGS WL LINGER. AS THE WEAKER FLOW VEERS TOWARD THE W LATER
ON WED MRNG...MORE SHSN/IFR VSBYS MAY IMPACT CMX LATE IN THE TAF
PERIOD.
&&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 438 PM EST TUE DEC 24 2013
AS THE PRES GRADIENT TIGHTENS OVER LAKE SUPERIOR THIS EVENING
BETWEEN DEPARTING SURFACE HI PRES RIDGE AND AN APPROACHING LO PRES
TROF...OPTED TO MAINTAIN GOING GALE WARNING FOR THE ECENTRAL
PORTIONS OF THE LAKE. AWAY FROM THIS FAVORED AREA...SOME GALE FORCE
GUSTS WILL BE POSSIBLE. CLOSER APPROACH AND THEN PASSAGE OF LO PRES
TROF AND WEAKER GRADIENT ON WED WILL CAUSE THE GALES TO DIMINISH AS
THE WINDS VEER TOWARD THE W-NW. NORTHWEST TO NORTH GALES WILL AGAIN
BE POSSIBLE SATURDAY NIGHT BEHIND AN ARCTIC COLD FRONT. HEAVY
FREEZING SPRAY IS ALSO EXPECTED INTO EARLY NEXT WEEK.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
WINTER WEATHER ADVISORY FROM 1 AM TO 10 AM EST WEDNESDAY FOR
MIZ014-085.
WINTER STORM WARNING FROM 1 AM TO 1 PM EST WEDNESDAY FOR MIZ007.
LAKE SUPERIOR...
GALE WARNING FROM 11 PM THIS EVENING TO 7 AM EST WEDNESDAY FOR
LSZ266.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...KC
LONG TERM...JLB
AVIATION...KC
MARINE...KC
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
1227 AM EST TUE DEC 24 2013
.SHORT TERM...(THIS EVENING THROUGH TUESDAY)
ISSUED AT 343 PM EST MON DEC 23 2013
LATEST WV SATELLITE IMAGERY AND RUC ANALYSIS SHOWS BROAD 5H TROUGH
SLOWLY PUSHING E ACROSS THE WRN GREAT LAKES THIS AFTERNOON. WEAK
850-500MB Q-VECTOR CONVERGENCE ASSOC WITH THIS TROUGH OVER LAKE
SUPERIOR WILL TRANSITION TO Q-VECTOR DIVERGENCE THIS EVENING. VIS
IMAGERY SHOWS NE WIND PARALLEL LAKE EFFECT SNOW BANDS ACROSS LAKE
SUPERIOR IMPACTING MAINLY FAR WESTERN AND NORTH CENTRAL UPPER MI. A
FEW OF THE MORE INTENSE BANDS HAVE PRODUCED PERIODS OF MODERATE
SNOW. LES HAS BEEN VERY FLUFFY WITH SNOW RATIOS 40-50/1.
MAIN FORECAST CONCERN IS CONTINUING LES EVENT FOR FAR WESTERN AND
NORTH CENTRAL COUNTIES INTO THIS EVENING AND THEN DIMINISHING LES
OVERNIGHT INTO TUE MORNING. EXPECT ADDITIONAL SNOWFALL AMOUNTS OF 2
TO 5 INCHES THROUGH THIS EVENING. BEST LOW-LVL CONVERGENCE SUGGESTS
MORE INTENSE LES BANDS AND THUS GREATEST SNOW AMOUNTS WILL BE OVER
ERN HALF OF MQT COUNTY INTO PERHAPS WRN ALGER COUNTY. GIVEN
EXPECTATION OF CONTINUING LES ACCUMULATION INTO AT LEAST THE EVENING
HRS WILL CONTINUE ADVISORIES FOR GOGEBIC-ONTONAGON AND MQT-BARAGA
INTO THE EARLY OVERNIGHT.
LES SHOULD GENERALLY BE WINDING DOWN BY LATE EVENING INTO OVERNIGHT
HRS WITH Q-VECT DIVERGENCE ACROSS THE AREA AND WEAKENING WIND
FIELDS. LOW-LVL CONVERGENCE MAY STRENGTHEN DUE TO WEAKENING WINDS
AND DEVELOPING LAND BREEZES TO ALLOW MORE LOCALLY INTENSE LES BANDS
TO FORM AND PERHAPS EVEN A MESOLOW OR TWO OFF THE PORCUPINE
MOUNTAINS AND OVER MQT BAY AS DEPICTED BY LOCAL AND REGIONAL
MESOSCALE MODELS. HOWEVER...WINDS BACKING TO THE WEST/SOUTHWEST
OVERNIGHT AHEAD OF ADVANCING SFC RDG AXIS SHOULD KEEP LES BANDS OR
MESOLOW FEATURES MOVING ENOUGH EASTWARD TO EFFECTIVELY LIMIT
ACCUMULATIONS FOR THE OVERNIGHT HRS.
DECREASING CLOUD COVER OVERNIGHT AND LIGHT WINDS WILL ALLOW
TEMPERATURES TO FALL OFF OUTSIDE OF THOSE AREAS WHERE THE LAKE
EFFECT SNOWS LINGER. COLDEST TEMPERATURES ARE EXPECTED OVER THE FAR
EAST AND INTERIOR WEST SECTIONS. THE WRN INTERIOR ALONG THE WI BDR
WITH LIKELY SEE A FEW LOCATIONS PLUMMET TO 10 BELOW OR COLDER WHERE
TYPICAL COLD SPOTS OVER LUCE COUNTY COULD ALSO DIP NEAR 10 BELOW
ZERO. GENERALLY FOLLOWED A BLEND OF THE BETTER PERFORMING CANADIAN
REGIONAL GEM AND ECMWF FOR MIN TEMPS.
TUESDAY...DECENT MODEL AGREEMENT THAT LINGERING LAKE EFFECT OVER
NCNTRL CWA WILL BE PUSHED OUT OVR SOUTH CENTRAL LK SUPERIOR THROUGH
THE MORNING AS WINDS BECOME SSW AHEAD OF APPROACHING SHORTWAVE AND
SFC TROUGH OVER THE NRN PLAINS. MAY BE ABLE TO SNEAK IN SOME
SUNSHINE OVER MUCH OF THE CWA INTO EARLY AFTN BEFORE HIGH CLOUDS
START INCREASING AHEAD OF SHORTWAVE TROUGH DROPPING ACROSS THE
NORTHERN PLAINS. WARM ADVECTION SSW FLOW WILL ALLOW FOR MAX TEMPS TO
REBOUND INTO THE TEENS ACROSS MUCH OF THE AREA.
.LONG TERM...(TUESDAY NIGHT THROUGH MONDAY)
ISSUED AT 310 PM EST MON DEC 23 2013
UPPER AIR PATTERN WILL CONSIST OF A 500 MB RIDGE ON THE WEST COAST
AND A TROUGH OVER THE NORTHERN PLAINS 00Z WED. NAM ALSO SHOWS A
CLOSED 500 MB LOW OVER NORTHERN ALBERTA 00Z WED. BOTH THE LOW AND
THE TROUGH MOVE TO THE EAST WITH THE REMAINS OF THE LOW HELPING TO
DIG A DEEP UPPER TROUGH INTO THE UPPER GREAT LAKES ON WED. NAM SHOWS
SOME 850-500 MB Q-VECTOR CONVERGENCE OVER THE CWA WITH DEEPER
MOISTURE TUE NIGHT LASTING INTO WED BEFORE BOTH MOVE OUT WED NIGHT
INTO THU. GFS AND ECMWF SHOW ABOUT THE SAME THING.
DID NOT MAKE TOO MANY CHANGES TO THE GOING FORECAST. CLIPPER TYPE
SYSTEM COMES IN FOR TUE NIGHT INTO WED AND WILL HAVE SOME LAKE
MICHIGAN LAKE ENHANCEMENT OVER THE ERN CWA WHICH WAS ALREADY COVERED
IN THE PREVIOUS FORECAST. COULD SEE UP TO 8 INCHES IN ERN
SCHOOLCRAFT AND LUCE COUNTIES FOR TUE NIGHT AND WED. DID LOWER
TEMPERATURES A BIT THOUGH EACH DAY FOR LOWS AND HIGHS TUE NIGHT
THROUGH THU AS THE TEMPERATURES SEEMED A BIT TOO WARM CONSIDERING
THE PERSISTENT COLD PATTERN WE HAVE BEEN IN.
IN THE EXTENDED...GFS AND ECMWF SHOW A 500 MB TROUGH OVER THE
CENTRAL U.S. 12Z FRI WITH A RIDGE OVER THE WESTERN U.S. UPPER FLOW
BECOMES MORE ZONAL OVER THE NORTHERN PLAINS AND UPPER GREAT LAKES
12Z SAT WHICH WILL MEAN A BRIEF WARMING TREND IS STARTING. A BROAD
500 MB TROUGH THEN MOVES INTO THE UPPER GREAT LAKES 12Z SUN AND INTO
MONDAY WITH COLD AIR ONCE AGAIN OVER THE AREA WITH THE DEEP UPPER
TROUGH. LAKE EFFECT SNOW WILL BE THE MAIN RULE FOR MOST OF THIS
FORECAST PERIOD WITH TEMPERATURES GOING BACK BELOW NORMAL SUNDAY
INTO MONDAY. CLIPPER SYSTEM MOVES THROUGH FOR SAT AND THIS WOULD BE
THE WARMEST DAY OF THE WEEK.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT)
ISSUED AT 1222 AM EST TUE DEC 24 2013
MAINLY MVFR CONDITIONS ARE EXPECTED TONIGHT WITH LINGERING LIGHT
LAKE EFFECT SNOW SHOWERS MOVING THROUGH NORTHERN UPPER MICHIGAN ON
LIGHT NRLY WINDS. EXPECT CIGS AND VSBYS TO IMPROVE TO VFR LATE
TONIGHT AT IWD AND TUE MORNING AT CMX AND SAW AS LAKE EFFECT COMES
TO AN ENDS WITH WINDS BACKING TO THE SOUTHWEST.
&&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 343 PM EST MON DEC 23 2013
NORTHEAST WINDS WILL GRADUALLY DIMINISH THROUGH THE DAY. HEAVY
FREEZING SPRAY WILL REMAIN A PROBLEM OVER THE WEST AND NORTH CENTRAL
PORTIONS OF LAKE SUPERIOR UNTIL THE PRESSURE GRADIENT RELAXES A BIT
MORE IN THE AFTERNOON. AFTER A BRIEF RESPITE...SOUTH WINDS PICK UP
AGAIN AHEAD OF THE NEXT SYSTEM MOVING THROUGH TO THE NORTH OF LAKE
SUPERIOR TUESDAY NIGHT WITH GALE FORCE WINDS TO 35 KNOTS EXPECTED
THEN...MAINLY FOR THE EASTERN PORTION OF THE LAKE. WINDS DIMINISH
WEDNESDAY AND REMAIN BELOW 20 KNOTS THROUGH FRIDAY.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
LAKE EFFECT SNOW ADVISORY UNTIL 3 AM EST EARLY THIS MORNING FOR
MIZ004-005.
LAKE SUPERIOR...
GALE WATCH FROM LATE TONIGHT THROUGH WEDNESDAY MORNING FOR
LSZ266.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...VOSS
LONG TERM...07
AVIATION...JLB
MARINE...VOSS
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
611 AM CST TUE DEC 24 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 403 AM CST TUE DEC 24 2013
ARCTIC HIGH PRESSURE WAS DRIFTING ACROSS THE EASTERN CWA EARLY THIS
MORNING WITH THE COLDEST TEMPERATURES SO FAR THIS WINTER. LOWS ARE
APPROACHING 30 BELOW ZERO ACROSS CENTRAL MN WITH 15 BELOW INTO
SOUTHERN MN AND NW WISCONSIN. STUBBORN CLOUDINESS ASSOCIATED WITH
THE UPPER WAVE OVERHEAD YESTERDAY MORNING WAS STILL CIRCULATING
AROUND ACROSS PARTS OF WEST CENTRAL WISCONSIN. SURFACE WINDS HAVE
ALREADY BECOME SOUTHERLY IN FAR WESTERN MN WITH SPEEDS OF 10 TO 15
MPH. THE WIND CHILL WARNING AND ADVISORY HEADLINES LOOK GOOD FOR
THIS MORNING WITH THE APPARENT TEMPERATURE FORECAST DROPPING OUT OF
THE ADVISORY/WARNING CRITERIA AROUND NOON TODAY...WHICH IS WHEN THE
CURRENT PRODUCTS EXPIRE. FORECAST HIGHS FOR THIS AFTERNOON REMAIN IN
THE SINGLE DIGITS TO LOW TEENS WITH LOWS TONIGHT ONLY A FEW DEGREES
BELOW THE HIGHS.
OUR NEXT ADVENTURE IN THE SHORT TERM FORECAST IS THE WAVE OF LOW
PRESSURE THAT WILL MOVE ACROSS THE FORECAST AREA THIS AFTERNOON AND
TONIGHT. OVERNIGHT MODEL RUNS ARE A LITTLE RICHER WITH THE SPECIFIC
HUMIDITY ON THE NAM/GFS 290K THETA SURFACES. WE ARE NOW SEEING 2.5
TO 3.5 G/KG FOR A SHORT PERIOD DURING THE AFTERNOON AND EVENING
ALONG WITH STRONG ADIABATIC OMEGA. THERE IS AN ALIGNMENT OF ABOUT 2
HOURS WHERE MAXIMUM OMEGA IS IN THE DENDRITIC GROWTH ZONE. THIS WILL
BE THE BEST PERIOD OF ACCUMULATING SNOW WITH SNOWFALL RATES
APPROACHING 1 INCH PER HOUR.
THE OVERALL IDEA ON THE SNOW FORECAST HAS NOT CHANGED MUCH WITH THE
LEADING EDGE OF THE SNOW PUSHING INTO WEST CENTRAL MN LATE THIS
MORNING...REACHING THE I-35 CORRIDOR IN THE 3-4 PM TIME FRAME AND
EAU CLAIRE TO LADYSMITH BETWEEN 6 AND 7 PM. THE PRECIPITATION
PLACEMENT AND AMOUNTS ARE VERY SIMILAR TO THE PREVIOUS FORECAST
PACKAGE. THE SNOW ACCUMULATION FORECAST WORKS OUT TO BE 3 TO 4
INCHES GENERALLY ALONG AND NORTH OF A LINE FROM REDWOOD FALLS
THROUGH RED WING TO EAU CLAIRE WITH 2 TO 3 INCHES SOUTH OF THIS
LINE. THE ACCUMULATING SNOW SHOULD END EARLY THIS EVENING ACROSS
WEST CENTRAL MN...ALONG THE I-35 CORRIDOR BY MIDNIGHT...AND IN THE
EAU CLAIRE TO LADYSMITH AREAS AROUND 4 AM WEDNESDAY MORNING. ONE
CONCERN TODAY AS THAT AS THE SNOW SPREADS INTO WEST CENTRAL MN
SURFACE WINDS WILL BE SOUTHERLY AT 15 TO 20 MPH. THIS COULD LEAD TO
A COUPLE HOUR PERIOD OF POOR VISIBILITY IN SNOW/BLOWING SNOW. ON THE
PLUS SIDE...WINDS WILL SUBSIDE DURING THE AFTERNOON AS THE PRESSURE
GRADIENT WEAKENS. HENCE...A WINTER WEATHER ADVISORY REMAINS IN
EFFECT FOR ALL OF THE CWA THIS AFTERNOON AND TONIGHT.
.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 403 AM CST TUE DEC 24 2013
I FEEL LIKE I AM BEGINNING TO SOUND LIKE A BROKEN RECORD HERE...BUT
VERY LITTLE CHANGE IS EXPECTED WITH OUR WEATHER PATTERN OVER THE
NEXT WEEK...WITH NW FLOW EXPECTED TO BE THE DOMINATE FEATURE AS WE
MAINTAIN A MEAN RIDGE OVER THE ERN PAC AND MEAN TROUGH OVER ERN NOAM
AS THE POLAR VORTEX OVER HUDSON BAY DEEPENS/EXPANDS THIS WEEKEND
INTO NEXT WEEK.
ALTHOUGH LITTLE CHANGE IS EXPECTED IN THE WEATHER PATTERN...DID MAKE
SOME BIG CHANGES TO POPS IN THE UPWARD DIRECTION WEDNESDAY AND
THURSDAY...WITH LIKELY POPS NOW INDICATED FOR WEDNESDAY AND 40S
INTRODUCED FOR THURSDAY. WEDNESDAY IS THE RESULT OF A RATHER STRONG
UPPER WAVE DROPPING DOWN ON THE BACK SIDE OF TODAY/S SYSTEM. THE NAM
CONTINUES TO SHOW A 5 PVU POTENTIAL VORTICITY ANOMALY WORKING DOWN
I-94 DURING THE DAY. TRACK RECORDS FOR WAVES OF THIS STRENGTH SO FAR
THIS MONTH HAS BEEN FOR A HEALTHY AMOUNT OF LIGHT FLUFFY SNOW...AND
WITH THIS EXPECTED...INCREASED POPS SIGNIFICANTLY FOR CHRISTMAS DAY.
NOT EXPECTING MUCH MORE THAN A HALF TO ONE INCH OF SNOW...BUT LOOKS
GOOD FOR YET ANOTHER HIGH POP/VERY LOW QPF EVENT.
FOR THURSDAY...THE 24.00 MODELS ACTUALLY CAME IN SIGNIFICANTLY
DIFFERENT THAN PREVIOUS RUNS IN TERMS OF TEMPERATURES AND
DEWPS...WITH BOTH ABOUT 10 DEGREES WARMER THAN PREVIOUS RUNS. FOR
THOSE VARIABLES...DID A BLEND OF 00Z GUIDANCE WITH THE GOING
FORECAST TO KEEP FROM HAVING A HUGE CHANGE IN THE FORECAST. THE BIG
IMPACT OF THIS IS THAT AS THE NEXT UPPER WAVE MOVES ACROSS THE AREA
THURSDAY AFTERNOON...IT HAS SIGNIFICANTLY MORE MOISTURE TO WORK WITH
THAN WHAT MODELS HAD BEEN SHOWING PREVIOUSLY. IN THE WARM SECTOR
WORKING OUT AHEAD OF THIS WAVE...THE GFS/NAM ARE SHOWING SFCS DEWPS
UP AROUND 20...WITH SPEC HUMIDITY ON THE 295K SFC UP AROUND 2.5
G/KG. MOST GUIDANCE PAINTS THIS BAND COMING DOWN ALONG/NORTH OF
I-94...SO THIS IS WHERE WE STARTED WITH THE INTRODUCTION OF 40 POPS.
GIVEN THE HIGHER MOISTURE...THIS WAVE MAY HAVE THE POTENTIAL TO
PRODUCE A WHOLE WHOPPING 1-2 INCHES OF LIGHT FLUFFY SNOW.
FROM THE SNOW END OF THINGS...WE ACTUALLY LOOK TO GET A BREAK FRIDAY
AND SATURDAY AS RIDGING NUDGES INTO THE PLAINS...PUSHING THESE PESKY
NW FLOW WAVES NORTH OF THE MPX AREA. OF COURSE THE ADVANTAGE TO THIS
IS THAT WE WILL HAVE A COUPLE OF BRIEF WARM DAYS FRIDAY AND LEAST
THE FIRST HALF OF SATURDAY BEFORE ARCTIC AIR RETURNS. STILL LOOKS
LIKE SOME HIGHS IN THE 30S FOR SOUTHERN MN LOOK LIKE A POSSIBILITY
FRIDAY AND SATURDAY.
ALTHOUGH NOT IN THE FORECAST NOW...THE NEXT CHANCE FOR LIGHT SNOW
WILL LIKELY BE SATURDAY NIGHT INTO SUNDAY AS THE NEXT POWERFUL
BLAST OF ARCTIC AIR RETURNS. MORE WORRISOME THAN THE LIGHT SNOW
THOUGH ARE THE WINDS THE ECMWF/GEM/GFS SHOW DEVELOPING IN THE COLD
ADVECTION BEHIND THE FRONT. GFS BUFKIT SOUNDINGS OUT IN WRN AND SRN
MN SUNDAY NIGHT ARE SHOWING MID CHANEL MIXING WINDS OF AROUND 35
KTS...WITH TOP OF THE CHANNEL OF 45 KTS. THIS WOULD SUGGEST THE
POTENTIAL FOR BLIZZARD CONDITIONS SATURDAY NIGHT AS THIS COLD AIR
ARRIVES...SO THIS WILL NEED TO WATCHED CLOSELY IN THE COMING DAYS.
AS FOR WHAT COMES BEHIND THIS FRONT...WELL LETS JUST SAY IT/S NOT
PRETTY IF YOU HAVE HAD ENOUGH OF THE ARCTIC AIR! BOTH THE GFS/ECMWF
SHOW SUNDAY THROUGH AT LEAST WEDNESDAY NEXT WEEK BEING THE COLDEST
STRETCH OF DAYS WE HAVE SEEN YET. COULD VERY WELL END UP SEEING A 2
TO 4 DAY STRETCH WHERE MUCH OF THE AREA STRUGGLES TO SEE HIGHS GET
ABOVE ZERO WITH LOWS AGAIN GOING DOUBLE DIGITS BELOW ZERO ACROSS
MUCH OF THE AREA. ENJOY!
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z WEDNESDAY MORNING)
ISSUED AT 611 AM CST TUE DEC 24 2013
IFR CEILINGS HAVE BLOSSOMED EARLY THIS MORNING ACROSS WEST CENTRAL
WI...JUST NICKING KRNH WITH KEAU NEARLY IN THE CENTER. RAP 0.5KM
CONDENSATION PRESSURE DEFICITS SHOW THE SATURATION MOVING NORTHEAST
OF THESE TWO TAFS SITES BY 15Z. MOVEMENT FROM SATELLITE WOULD
SUPPORT THIS TREND. BACK TO THE WEST...STRONG SOUTH TO SOUTHEAST
WINDS HAVE DEVELOPED ALONG THE MN/DAKOTA BORDER AS THE PRESSURE
GRADIENT TIGHTENS AHEAD OF AN INCOMING LOW PRESSURE SYSTEM. WHERE
THE SNOW HAS DEVELOPED WELL BACK IN WESTERN NORTH
DAKOTA...CEILINGS DROP QUICKLY TO LOW MVFR WITH SOME IFR. FOLLOWED
THE LATEST HOPWRF REFLECTIVITY FORECAST FOR THE TIMING ON BRINGING
THE SNOW INTO THE TAF SITES. THIS WAS VERY CLOSE TO THE PREVIOUS
SET WITH ONLY MINOR CHANGES MADE. MOST SHORT TERM SOLUTIONS POINT
TO A 3 TO 4 HOUR PERIOD OF MODERATE SNOW AS THE BEST FORCING MOVES
THROUGH DURING THE AFTERNOON AND EVENING. CURRENT THINKING IS THAT
MVFR CEILINGS WILL PREVAIL IN THE WAKE OF THE SNOW OVERNIGHT AND
ON CHRISTMAS. LIGHT SNOW SHOULD SPREAD BACK IN FROM THE NORTHWEST
DURING THE DAY ON CHRISTMAS AS THE ARCTIC WAVE TRAIN CONTINUES.
KMSP...
NO CONCERNS UNTIL LATE AFTERNOON WHEN SNOW AND MVFR CEILINGS
ARRIVE. A PERIOD OF IFR OR LOWER CEILINGS/VSBYS IN MODERATE SNOW
FORECAST IN THE 23Z-03Z TIME FRAME. SNOW ACCUMULATION REACHING 3
INCHES BY LATE IN THE EVENING WITH THE SNOW TAPERING OF
SIGNIFICANTLY AFTER 06Z. SE WINDS INCREASING TO 12-15 KNOTS THIS
MORNING AND CONTINUING INTO THIS EVENING. WINDS LOWERING BELOW 10
KNOTS LATE IN THE EVENING AND VEERING W OVERNIGHT.
/OUTLOOK FOR KMSP/
WED...MVFR WITH -SN POSSIBLE. WINDS W 10-15KTS.
THU...VFR. CHANCE MVFR CIGS/VSBYS IN -SN. WINDS S AT 5 KTS.
FRI...VFR. WINDS SW 5-10 KTS.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...WINTER WEATHER ADVISORY FROM NOON TODAY TO MIDNIGHT CST TONIGHT
FOR MNZ042>045-049>052-057>062-065>069-073>076-082>084-091-
092.
WIND CHILL ADVISORY UNTIL NOON CST TODAY FOR MNZ043>045-050>053-
059>063-068>070-076>078-084-085-091>093.
WINTER WEATHER ADVISORY FROM 9 AM THIS MORNING TO 9 PM CST THIS
EVENING FOR MNZ041-047-048-054>056-064.
WIND CHILL WARNING UNTIL 9 AM CST THIS MORNING FOR MNZ041-047-
048-054>056-064.
WIND CHILL WARNING UNTIL NOON CST TODAY FOR MNZ042-049-057-058-
065>067-073>075-082-083.
WINTER WEATHER ADVISORY FROM 3 PM THIS AFTERNOON TO 3 AM CST
WEDNESDAY FOR MNZ053-063-070-077-078-085-093.
WI...WINTER WEATHER ADVISORY FROM 3 PM THIS AFTERNOON TO 3 AM CST
WEDNESDAY FOR WIZ014>016-023>028.
&&
$$
SHORT TERM...RAH
LONG TERM...MPG
AVIATION...RAH
AREA FORECAST DISCUSSION
NWS NORTH PLATTE NE
1137 AM CST TUE DEC 24 2013
.SYNOPSIS...
ISSUED AT 327 AM CST TUE DEC 24 2013
POTENT VORT MAX NOTED ON WATER VAPOR ACROSS MONTANA MOVING
SOUTHEAST.ASSOCIATED WITH THE VORT MAX WAS A 1010MB LOW
PRESSURE CENTER ACROSS CENTRAL MONTANA. A STRONG ARCTIC HIGH
PRESSURE CENTER OF 1039MB WAS LOCATED ACROSS NORTHERN MISSOURI.
OTHERWISE A WEAK LOW PRESSURE TROUGH WAS ORIENTED NORTH TO
SOUTH ALONG THE EAST COAST...WITH HIGH PRESSURE LOCATED ALONG
THE WEST COAST.
&&
.UPDATE...
ISSUED AT 958 AM CST TUE DEC 24 2013
UPDATED FORECAST TO REFINE PRECIP TYPE ACROSS NORTHERN NEBRASKA
THROUGH THE MORNING HOURS. VISIBLE SATELLITE SHOWS SOME WEAK
CONVECTIVE ENHANCEMENT ASSOCIATED WITH ECHOES COMING SOUTHEAST
INTO NW CHERRY COUNTY. THIS IS SOMEWHAT SUPPORTED BY CROSS
SECTIONS OF INSTABILITY PARAMETERS IN THAT AREA...ALTHOUGH ASOS
REPORTS ARE INCONCLUSIVE. IR SATELLITE AND RAP MID LEVEL
DEFORMATION VECTORS INDICATE INCREASING FRONTOGENESIS IN THIS
REGION WHICH THE MODELS HAVE ADVERTISED WELL. STILL...SOUNDINGS
SUGGEST SOME DRY AIR TO BE OVERCOME AND CURRENT ECHO COVERAGE
SUPPORTS THAT. IF WEAK CONVECTION IS INDEED A POSSIBILITY...SLEET
POTENTIAL WILL INCREASE AND HENCE MENTION OF SLEET IS INCLUDED FOR
THE NORTHERN MOST FORECAST AREA. FURTHER SOUTH...FCST REMAINS
CLOSE TO WHERE IT WAS. TEMPERATURES ARE TRICKY FOR TODAY AS WARM
AIR SURGES EASTWARD AHEAD OF SOUTHWARD ADVANCING COLD FRONT.
MIXING POTENTIAL IS IN QUESTION WITH EXISTING SNOW COVER...SO
TEMPS WERE ONLY LOWERED SLIGHTLY IN THE NORTH WHERE CLOUD COVER
AND PRECIP SHOULD LIMIT POTENTIAL.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 327 AM CST TUE DEC 24 2013
THE MAIN FORECAST CHALLENGES OVER THE NEXT 24 HOURS DEAL WITH
PRECIPITATION CHANCES AND WINDS IN ASSOCIATION WITH A CLIPPER
SYSTEM. ATTM...SURFACE LOW PRESSURE WAS LOCATED OVER NERN WYOMING
PER 09Z SFC ANALYSIS WITH A WARM FRONT EXTENDING SOUTH FROM THIS
FEATURE THROUGH EASTERN WYOMING...AND AN ARCTIC COLD FRONT
EXTENDING NORTHWEST OF THE SURFACE LOW INTO NORTH CENTRAL MONTANA.
OVER THE NEXT 12 HOURS...SURFACE LOW PRESSURE WILL TRACK TO THE
EAST SOUTHEAST FROM NERN WYOMING INTO NERN NEBRASKA. EAST OF THE
APPG WARM FRONT THIS MORNING...THERE WILL BE AN INCREASED THREAT
FOR PRECIPITATION AS MID LEVEL LIFT INCREASES PER MID LEVEL
FRONTOGENESIS AND OMEGA. TEMPERATURE PROFILES PER BUFKIT SOUNDING
DATA ARE INDICATIVE OF A VERY SHALLOW...ABOVE FREEZING LAYER ABOVE
THE SUBZERO SURFACE LATER THIS MORNING. GIVEN THE VERY SHALLOW
NATURE OF THE ARCTIC AIR THIS MORNING...DECIDED TO KEEP A MENTION
OF SLEET ALONG WITH LIGHT SNOW THIS MORNING. ONCE THE COLD FRONT
CLEARS LATER THIS AFTERNOON...THE THREAT FOR PCPN WILL SHIFT TO
ALL SNOW. MID LEVEL LIFT CONTINUES TO BE MOST FAVORABLE ACROSS THE
NORTH CENTRAL AND NERN CWA LATER TODAY AND WILL CONTINUE HIGHEST
POPS IN THESE AREAS. UTILIZING A BLEND OF THE MET AND MAV SOLNS
YIELDED QPFS OF UNDER A TENTH OF AN INCH TDY IN THE NORTH...AND
WILL KEEP CORRESPONDING SNOW ACCUMS TO AN INCH OR LESS. THEN THERE
IS THE WIND BEHIND THE FRONT. THE LATEST NAM BUFKIT SOUNDINGS HAVE
A TIGHT WINDOW OF NEAR ADVISORY WINDS IN THE PANHANDLE COUNTIES
AROUND 1 PM THIS AFTERNOON...WITH WINDS FALLING BACK INTO THE 20
TO 30 MPH RANGE BY EARLY EVENING. DECIDED TO FORGO AN ADVISORY FOR
THE PANHANDLE COUNTIES ATTM AS THE NAM BUFKIT SOUNDINGS WINDS ARE
NOT SUPPORTED WITH THE MAV GUIDANCE WHICH KEEPS WINDS BELOW
ADVISORY CRITERIA THIS AFTERNOON. FOR TONIGHT...WINDS WILL
DECREASE SOMEWHAT...BUT REMAIN IN THE 10 TO 15 MPH RANGE...WITH
EXCEPTION IN THE VALLEY...WHERE WINDS WILL BE BELOW 10 MPH. WITH A
LIGHT BREEZE CONTINUING INTO THE OVERNIGHT...TEMPS WILL BE MILD
WITH READINGS IN THE TEENS EXPECTED. LOWS WILL BOTTOM OUT IN THE
HIGH SINGLE DIGITS IN THE PLATTE RIVER VALLEY WITH LIGHT WESTERLY
WINDS FORECAST.
.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 327 AM CST TUE DEC 24 2013
VERY LITTLE CHANGE IS EXPECTED THE REST OF THE WEEK AND INTO THE
UPCOMING WEEKEND...AS A PROGRESSIVE NORTHWEST FLOW ALOFT WILL
CONTINUE. SEVERAL MID LEVEL DISTURBANCES WILL BE LOCATED WITHIN THE
FLOW...BUT ANY LIGHT PRECIPITATION WITH THESE DISTURBANCES SHOULD
REMAIN NORTH OF OUR AREA.
CHRISTMAS DAY THROUGH FRIDAY WILL BE DOMINATED BY A PACIFIC AIRMASS
AND DOWNSLOPE WESTERLY WINDS. HIGH TEMPERATURES WILL WARM FROM THE
30S TO LOWER 40S CHRISTMAS DAY...TO THE MID 40S TO MID 50S BY FRIDAY.
AN ARCTIC COLD FRONT WILL DIVE SOUTH THROUGH THE NORTHERN PLAINS
SATURDAY...ENTERING NEBRASKA SATURDAY AFTERNOON. THIS WILL BRING
COLDER CONDITIONS TO THE AREA SUNDAY. LATEST INDICATIONS ARE THAT
THE COLDEST AIR BEHIND THE FRONT WILL SLIDE FROM THE NORTHERN
PLAINS INTO THE MISSISSIPPI VALLEY. MILD CONDITIONS SHOULD THEN
RETURN FOR AT LEAST WESTERN NEBRASKA BY MONDAY. THE ECMWF IS MOST
SUPPORTIVE OF THIS SCENARIO...WITH THE GFS KEEPING THE COLDER AIR
A BIT FARTHER WEST. EVEN THE COLDER GFS SCENARIO SUPPORTS HIGHS
WELL INTO THE 30S BY MONDAY ACROSS WESTERN NEBRASKA...WITH MID TO
UPPER 20S FARTHER EAST.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z WEDNESDAY AFTERNOON)
ISSUED AT 1136 AM CST TUE DEC 24 2013
TRICKY FORECAST IN TIMING ONSET OF PRECIPITATION AND INCREASES IN
WIND. COLD FRONT IS PROGRESSING SOUTHWARD AND HAS MADE IT THROUGH
THE NORTHWESTERN PORTION OF THE FORECAST AREA AND KVTN WINDS HAVE
INCREASED IN THE LAST HOUR. IN ADDITION...IR SAT PICS AND RAP
MODEL MID LEVEL DEFORMATION VECTORS CONTINUE TO INDICATE
FRONTOGENETIC FORCING ACROSS SD AND INTO FAR NRN NEBRASKA.
HOWEVER...DRY AIR AND MORE OF A FRONTOLYTICAL STRUCTURE SUGGEST
LESSER CHANCES FOR RAIN OR SNOW SHOWERS AS THE AFTERNOON
PROGRESSES IN SOUTHWEST NEBRASKA...WHICH IS IN LINE WITH CURRENT
RADAR RETURNS.
THE TAF FOR KVTN INCLUDES THE MENTION AND CIGS NEARING IFR FOR THE
AFTERNOON HOURS BEFORE THE FORCING AND ASSOCIATED UPPER LEVEL
SUPPORT MOVES QUICKLY OUT OF THE AREA THIS EVENING. AS FOR
KLBF...NO MENTION OF PRECIP IN THE TAF BECAUSE OF THE PREVIOUSLY
MENTIONED DRY AIR IN THE MID LEVELS AND LESSER MID LEVEL FORCING
FOR ASCENT. CONFIDENCE IS ONLY MODERATE ON THIS IDEA AND WITH A
WEAK CONVECTIVE NATURE TO THE PRECIPITATION WILL HAVE TO MONITOR
TRENDS THIS AFERNOON. SOME CONCERN FOR LIGHT FOG DURING THE EARLY
MORNING HOURS FOR KLBF...BUT HAVE NOT INCLUDED AT THIS TIME DUE TO
A LACK OF CONFIDENCE IN LOW LEVEL SATURATION.
&&
.LBF WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...JWS
SYNOPSIS...TAYLOR
SHORT TERM...CLB
LONG TERM...TAYLOR
AVIATION...JWS
AREA FORECAST DISCUSSION
NWS NORTH PLATTE NE
958 AM CST TUE DEC 24 2013
.SYNOPSIS...
ISSUED AT 327 AM CST TUE DEC 24 2013
POTENT VORT MAX NOTED ON WATER VAPOR ACROSS MONTANA MOVING
SOUTHEAST.ASSOCIATED WITH THE VORT MAX WAS A 1010MB LOW
PRESSURE CENTER ACROSS CENTRAL MONTANA. A STRONG ARCTIC HIGH
PRESSURE CENTER OF 1039MB WAS LOCATED ACROSS NORTHERN MISSOURI.
OTHERWISE A WEAK LOW PRESSURE TROUGH WAS ORIENTED NORTH TO
SOUTH ALONG THE EAST COAST...WITH HIGH PRESSURE LOCATED ALONG
THE WEST COAST.
&&
.UPDATE...
ISSUED AT 958 AM CST TUE DEC 24 2013
UPDATED FORECAST TO REFINE PRECIP TYPE ACROSS NORTHERN NEBRASKA
THROUGH THE MORNING HOURS. VISIBLE SATELLITE SHOWS SOME WEAK
CONVECTIVE ENHANCEMENT ASSOCIATED WITH ECHOES COMING SOUTHEAST
INTO NW CHERRY COUNTY. THIS IS SOMEWHAT SUPPORTED BY CROSS
SECTIONS OF INSTABILITY PARAMETERS IN THAT AREA...ALTHOUGH ASOS
REPORTS ARE INCONCLUSIVE. IR SATELLITE AND RAP MID LEVEL
DEFORMATION VECTORS INDICATE INCREASING FRONTOGENESIS IN THIS
REGION WHICH THE MODELS HAVE ADVERTISED WELL. STILL...SOUNDINGS
SUGGEST SOME DRY AIR TO BE OVERCOME AND CURRENT ECHO COVERAGE
SUPPORTS THAT. IF WEAK CONVECTION IS INDEED A POSSIBILITY...SLEET
POTENTIAL WILL INCREASE AND HENCE MENTION OF SLEET IS INCLUDED FOR
THE NORTHERN MOST FORECAST AREA. FURTHER SOUTH...FCST REMAINS
CLOSE TO WHERE IT WAS. TEMPERATURES ARE TRICKY FOR TODAY AS WARM
AIR SURGES EASTWARD AHEAD OF SOUTHWARD ADVANCING COLD FRONT.
MIXING POTENTIAL IS IN QUESTION WITH EXISTING SNOW COVER...SO
TEMPS WERE ONLY LOWERED SLIGHTLY IN THE NORTH WHERE CLOUD COVER
AND PRECIP SHOULD LIMIT POTENTIAL.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 327 AM CST TUE DEC 24 2013
THE MAIN FORECAST CHALLENGES OVER THE NEXT 24 HOURS DEAL WITH
PRECIPITATION CHANCES AND WINDS IN ASSOCIATION WITH A CLIPPER
SYSTEM. ATTM...SURFACE LOW PRESSURE WAS LOCATED OVER NERN WYOMING
PER 09Z SFC ANALYSIS WITH A WARM FRONT EXTENDING SOUTH FROM THIS
FEATURE THROUGH EASTERN WYOMING...AND AN ARCTIC COLD FRONT
EXTENDING NORTHWEST OF THE SURFACE LOW INTO NORTH CENTRAL MONTANA.
OVER THE NEXT 12 HOURS...SURFACE LOW PRESSURE WILL TRACK TO THE
EAST SOUTHEAST FROM NERN WYOMING INTO NERN NEBRASKA. EAST OF THE
APPG WARM FRONT THIS MORNING...THERE WILL BE AN INCREASED THREAT
FOR PRECIPITATION AS MID LEVEL LIFT INCREASES PER MID LEVEL
FRONTOGENESIS AND OMEGA. TEMPERATURE PROFILES PER BUFKIT SOUNDING
DATA ARE INDICATIVE OF A VERY SHALLOW...ABOVE FREEZING LAYER ABOVE
THE SUBZERO SURFACE LATER THIS MORNING. GIVEN THE VERY SHALLOW
NATURE OF THE ARCTIC AIR THIS MORNING...DECIDED TO KEEP A MENTION
OF SLEET ALONG WITH LIGHT SNOW THIS MORNING. ONCE THE COLD FRONT
CLEARS LATER THIS AFTERNOON...THE THREAT FOR PCPN WILL SHIFT TO
ALL SNOW. MID LEVEL LIFT CONTINUES TO BE MOST FAVORABLE ACROSS THE
NORTH CENTRAL AND NERN CWA LATER TODAY AND WILL CONTINUE HIGHEST
POPS IN THESE AREAS. UTILIZING A BLEND OF THE MET AND MAV SOLNS
YIELDED QPFS OF UNDER A TENTH OF AN INCH TDY IN THE NORTH...AND
WILL KEEP CORRESPONDING SNOW ACCUMS TO AN INCH OR LESS. THEN THERE
IS THE WIND BEHIND THE FRONT. THE LATEST NAM BUFKIT SOUNDINGS HAVE
A TIGHT WINDOW OF NEAR ADVISORY WINDS IN THE PANHANDLE COUNTIES
AROUND 1 PM THIS AFTERNOON...WITH WINDS FALLING BACK INTO THE 20
TO 30 MPH RANGE BY EARLY EVENING. DECIDED TO FORGO AN ADVISORY FOR
THE PANHANDLE COUNTIES ATTM AS THE NAM BUFKIT SOUNDINGS WINDS ARE
NOT SUPPORTED WITH THE MAV GUIDANCE WHICH KEEPS WINDS BELOW
ADVISORY CRITERIA THIS AFTERNOON. FOR TONIGHT...WINDS WILL
DECREASE SOMEWHAT...BUT REMAIN IN THE 10 TO 15 MPH RANGE...WITH
EXCEPTION IN THE VALLEY...WHERE WINDS WILL BE BELOW 10 MPH. WITH A
LIGHT BREEZE CONTINUING INTO THE OVERNIGHT...TEMPS WILL BE MILD
WITH READINGS IN THE TEENS EXPECTED. LOWS WILL BOTTOM OUT IN THE
HIGH SINGLE DIGITS IN THE PLATTE RIVER VALLEY WITH LIGHT WESTERLY
WINDS FORECAST.
.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 327 AM CST TUE DEC 24 2013
VERY LITTLE CHANGE IS EXPECTED THE REST OF THE WEEK AND INTO THE
UPCOMING WEEKEND...AS A PROGRESSIVE NORTHWEST FLOW ALOFT WILL
CONTINUE. SEVERAL MID LEVEL DISTURBANCES WILL BE LOCATED WITHIN THE
FLOW...BUT ANY LIGHT PRECIPITATION WITH THESE DISTURBANCES SHOULD
REMAIN NORTH OF OUR AREA.
CHRISTMAS DAY THROUGH FRIDAY WILL BE DOMINATED BY A PACIFIC AIRMASS
AND DOWNSLOPE WESTERLY WINDS. HIGH TEMPERATURES WILL WARM FROM THE
30S TO LOWER 40S CHRISTMAS DAY...TO THE MID 40S TO MID 50S BY FRIDAY.
AN ARCTIC COLD FRONT WILL DIVE SOUTH THROUGH THE NORTHERN PLAINS
SATURDAY...ENTERING NEBRASKA SATURDAY AFTERNOON. THIS WILL BRING
COLDER CONDITIONS TO THE AREA SUNDAY. LATEST INDICATIONS ARE THAT
THE COLDEST AIR BEHIND THE FRONT WILL SLIDE FROM THE NORTHERN
PLAINS INTO THE MISSISSIPPI VALLEY. MILD CONDITIONS SHOULD THEN
RETURN FOR AT LEAST WESTERN NEBRASKA BY MONDAY. THE ECMWF IS MOST
SUPPORTIVE OF THIS SCENARIO...WITH THE GFS KEEPING THE COLDER AIR
A BIT FARTHER WEST. EVEN THE COLDER GFS SCENARIO SUPPORTS HIGHS
WELL INTO THE 30S BY MONDAY ACROSS WESTERN NEBRASKA...WITH MID TO
UPPER 20S FARTHER EAST.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z WEDNESDAY MORNING)
ISSUED AT 600 AM CST TUE DEC 24 2013
A FAST MOVING CLIPPER SYSTEM WILL SPREAD LIGHT SNOW OR FREEZING
PRECIPITATION TO NORTHERN NEBRASKA TODAY WITH GUSTY WINDS EXPECTED
ACROSS THE REMAINDER OF WESTERN AND NORTH CENTRAL NEBRASKA. FOR
THE KLBF TERMINAL...EXPECT INCREASING CLOUDINESS TODAY WITH CIGS
DROPPING DOWN TO 5000 FT AGL. WINDS WILL BE FROM THE NORTHWEST AT
15 TO 25 KTS TODAY...DIMINISHING TO UNDER 10 KTS TONIGHT. FOR THE
KVTN TERMINAL...LIGHT SNOW OR FREEZING PRECIPITATION IS POSSIBLE
LATER THIS MORNING INTO THE AFTERNOON HOURS WITH VISBYS DOWN TO
1SM. CIGS WILL LOWER TO 2000 FT AGL BY MIDDAY. WINDS WILL BE FROM
THE NORTHWEST OR NORTH AT 15 TO 25 KTS TODAY...DECREASING TO 10 TO
15 KTS TONIGHT.
&&
.LBF WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...JWS
SYNOPSIS...TAYLOR
SHORT TERM...CLB
LONG TERM...TAYLOR
AVIATION...CLB
AREA FORECAST DISCUSSION
NWS RALEIGH NC
645 AM EST TUE DEC 24 2013
.SYNOPSIS...BEHIND A COLD FRONT MOVING OFF OF THE CAROLINA COAST
THROUGH EARLY AFTERNOON...HIGH PRESSURE BUILDS OVER THE REGION. HIGH
PRESSURE REMAINS AT LEAST THROUGH CHRISTMAS NIGHT. WEAK LOW PRESSURE
DEVELOPS OFF OF THE CAROLINA COAST THURSDAY.
&&
.NEAR TERM /THROUGH TODAY/...
AS OF 255 AM TUESDAY...
THE SURFACE COLD FRONT CONTINUES TO MAKE GRADUAL EASTWARD PROGRESS
OFFSHORE OF THE CAROLINAS...THOUGH WEAK SURFACE CYCLONIC FLOW
CONTINUES ON THE LATEST SURFACE ANALYSIS OVER THE SOUTHEAST PART OF
THE STATE. PATCHES OF LIGHT RAIN PERSISTED THERE UNDERNEATH THE
SOUTHWEST FLOW ALOFT...BUT DURING THE MORNING THE MORE MOIST FLOW
ALOFT WILL ALSO SHIFT EAST AS THE UPPER TROUGH ON WATER VAPOR...
MOVING INTO THE TENNESSEE VALLEY...MOVES INTO AND THEN ACROSS THE
STATE. THE HRRR WRF HAS BEEN CONSISTENT WITH ITSELF...AND WITH THE
DIMINISHING MOISTURE NOTED ON GFS BUFR SOUNDINGS...THAT MUCH OF THE
PATCHY LIGHT RAIN SHOULD BE MOVING OFF TO THE EAST OF CENTRAL NORTH
CAROLINA BY AROUND 12Z. WILL RETAIN A SLIGHT CHANCE OF RAIN EAST OF
INTERSTATE 95 FOR THE EARLY DAYLIGHT HOURS...THEN WILL SHOW DRY
CONDITIONS FOR THE REST OF THE DAY WITH CHANCES LESS THAN SLIGHT.
EVEN THOUGH THE UPPER TROUGH IS WELL DEFINED ON WATER VAPOR
IMAGERY...THE GUIDANCE CONSENSUS IS DRIER THAN 24 HOURS AGO...MAKING
THE CHANCES FOR SPRINKLES WITH THE APPROACH OF THE TROUGH ALOFT
REMOTE. TOO MUCH MID-LEVEL DRY AIR IS FORECAST...COINCIDENT WITH DRY
AIR TO OUR WEST AS NOTED ON THE 00Z UPPER-AIR ANALYSIS. EVEN THE
TREND IS DRIER IN THE LOWER LEVELS...THOUGH EXPECT LINGERING
STRATOCU INTO THE MORNING IN MANY AREAS.
THE SURFACE GRADIENT TIGHTENS TODAY AS HIGH PRESSURE BUILDS IN
BEHIND THE DEPARTING FRONT. BUFR SOUNDINGS SUGGEST ENOUGH MIXING
THAT FOR A PERIOD THIS AFTERNOON WIND GUSTS SHOULD REACH INTO THE
UPPER TEENS TO LOWER 20S KNOTS...WITH NORTHERLY WINDS BACKING MORE
NORTHWEST WITH MIXING. 1000-850MB THICKNESSES WILL BE FALLING DURING
THE DAY...BUT THEIR VALUES SUGGEST HIGHS CLOSE TO MOS GUIDANCE BUT
WITH ONLY MINIMAL RECOVERY FROM LATE NIGHT TEMPERATURES...FOR HIGHS
IN THE MID 40S TO AROUND 50.
&&
.SHORT TERM /TONIGHT THROUGH WEDNESDAY NIGHT/...
AS OF 255 AM TUESDAY...
HIGH PRESSURE REMAINS FOR MUCH OF THIS PERIOD...WITH PRECIPITABLE
WATER VALUES MOSTLY BELOW A QUARTER-INCH AND K INDICES HIGHLY
NEGATIVE. DRY SURFACE DEW POINTS MOVE IN AS WELL. BUFR SOUNDINGS AND
RELATIVE HUMIDITY FORECASTS ARE DRY...SUGGESTIVE OF CLEAR OR MOSTLY
CLEAR CONDITIONS INTO WEDNESDAY NIGHT. LOWS TONIGHT IN THE
20S...WITH HIGHS WEDNESDAY IN THE LOWER TO MID 40S...NEARER THE
SLIGHTLY WARMER MAV MOS GUIDANCE WHICH IS CLOSER TO EXPECTED VALUES
BASED ON 1000-850MB THICKNESSES.
WEDNESDAY NIGHT...THERE IS SOME GUIDANCE DIFFERENCE ON THE AMOUNT OF
HIGH CLOUDS THAT COULD MOVE INTO CENTRAL NORTH CAROLINA WITH THE
APPROACH OF A JET AXIS ALOFT...AND LOWERING HEIGHTS. THE NAM IS
CERTAINLY DRIER THAN THE GFS...WHICH IS DEEPER WITH THE ENERGY ALOFT
AND LOWERS PRESSURES MORE OFF OF THE CAROLINA COAST BY 12Z THURSDAY.
THE 00Z ECMWF OFFERS A GOOD COMPROMISE...SHOWING A FEW HIGH CLOUDS
STARTING TO ENCROACH ON CENTRAL NORTH CAROLINA FROM THE SOUTH LATE
IN THE DAY WEDNESDAY...AND SLOWLY SPREADING NORTH OVER MUCH OF THE
AREA WEDNESDAY NIGHT...LIKELY MORE OPAQUE SOUTH. WILL GO CLOSER TO
THE COLDER MET GUIDANCE WEDNESDAY NIGHT IN THE TRIAD AND NEAR THE
VIRGINIA BORDER...WITH A BLEND IN THE MIDDLE INCLUDING THE TRIANGLE
AND KRWI...AND CLOSER TO THE WARMER MAV GUIDANCE TOWARD KFAY. THIS
RESULTS IN LOWS IN THE LOWER 20S TOWARD KTDF...25 TO 30 OVER THE
SANDHILLS AND SOUTHERN COASTAL PLAIN...AND MID 20S IN BETWEEN.
&&
.LONG TERM /THURSDAY THROUGH MONDAY/...
AS OF 300 AM TUESDAY...
A SOUTHERN STREAM WAVE WILL TRACK ACROSS THE SOUTHEAST ON
THURSDAY...WITH A NORTHERN STREAM CLIPPER ON ITS HEELS. MODELS
INDICATE A WEAK SURFACE LOW MAY DEVELOP OFF THE NC/SC COAST IN
RESPONSE TO THE WEAK DPVA AND UPPER DIVERGENCE IN THE RIGHT FRONT
ENTRANCE REGION OF AN INTENSIFYING UPPER JET OVER THE MID-ATLANTIC
STATES. HOWEVER...FORECAST SOUNDINGS SHOW LIMITED MID-LEVEL
MOISTURE INLAND AND THUS DONT PRODUCE ANY QPF OVER THE RAH CWA.
CIRRUS SHOULD BE RATHER ABUNDANT...AT LEAST EARLY IN THE
DAY...BEFORE BEING SHUNTED EASTWARD WITH THE PASSING NORTHERN STREAM
TROUGH AXIS. THIS WILL LIMIT SOME OF THE MODERATION OF
TEMPS....THOUGH HIGHS SHOULD STILL REACH SEASONAL NORMS...48-52.
LOWS THURSDAY NIGHT 26-31.
THE REMAINDER OF THE EXTENDED PERIOD WILL BE MOSTLY DOMINATED BY THE
NORTHERN STREAM AS SHORTWAVES MOVING ACROSS THE GREAT LAKES REGION
SLOWLY CARVE OUT A LONGWAVE TROUGH OVER THE EASTERN US. THIS IS
SUPPORTED BY A TREND TOWARD NEGATIVE NAO/AO PHASES IN THE MEDIUM
RANGE. ANOTHER SOUTHERN STREAM SHORTWAVE AND ASSOCIATED POTENTIAL
SURFACE LOW SHOULD REMAINED SUPPRESSED OFFSHORE
SUNDAY/MONDAY...THOUGH THE 00Z ECMWF TRENDED FURTHER WEST WITH
MOISTURE ON SUNDAY. WILL LEAVE THE FORECAST DRY AT THIS TIME.
PERIODS OF CIRRUS WILL LIKELY PLAGUE THE AREA OVER THE
WEEKEND...WITH HIGHS REBOUNDING A BIT...INTO THE LOW TO MID 50S...
BEFORE WHAT APPEARS TO BE A MOSTLY DRY COLD FRONT CROSSES THE AREA
EARLY NEXT WEEK.
&&
.AVIATION /12Z TUESDAY THROUGH SATURDAY/...
AS OF 645 AM TUESDAY...
VFR CONDITIONS OVER THE WESTERN PIEDMONT WERE SLOWLY SPREADING EAST
AND THEY WILL GRADUALLY SPREAD OVER CENTRAL NORTH CAROLINA DURING
THIS EARLY MORNING...WITH KFAY LIKELY BEING PREDOMINANTLY VFR BY
14Z. THEN...CURRENTLY EXPECT BROKEN VFR-LEVEL CEILINGS ENDING BY
EARLY AFTERNOON. WITH MIXING TODAY...WINDS SHOULD BACK MORE TO THE
NORTHWEST WITH GUSTS IN THE 20S KNOTS AS THE SURFACE GRADIENT
TIGHTENS. WINDS WILL DIMINISH THIS EVENING AS HIGH PRESSURE
CONTINUES TO BUILD OVER THE AREA...THOUGH NORTHERLY WINDS TOWARD
KRWI AND KFAY MAY BE MORE NOTICEABLE A LITTLE LONGER INTO THE
OVERNIGHT HOURS DUE TO THE TIGHTER GRADIENT IN PLACE THERE COMPARED
TO THE REST OF CENTRAL NORTH CAROLINA.
BEYOND THE 12Z VALID TAF PERIOD...EXPECT VFR CONDITIONS. BASED ON
THE LATEST GFS MODEL GUIDANCE...THERE IS A LOW PROBABILITY OF SUB-
VFR CONDITIONS AT KFAY AND KRWI LATE WEDNESDAY NIGHT INTO EARLY
THURSDAY AS WEAK LOW PRESSURE DEVELOPS OFF OF THE CAROLINA COAST.
OTHER GUIDANCE APPEARS DRIER AS OF THIS WRITING.
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...DJF
NEAR TERM...DJF
SHORT TERM...DJF
LONG TERM...SMITH
AVIATION...DJF
AREA FORECAST DISCUSSION...RETRANSMITTED
NWS RALEIGH NC
300 AM EST TUE DEC 24 2013
.SYNOPSIS...BEHIND A COLD FRONT MOVING OFF OF THE CAROLINA COAST
THROUGH EARLY AFTERNOON...HIGH PRESSURE BUILDS OVER THE REGION. HIGH
PRESSURE REMAINS AT LEAST THROUGH CHRISTMAS NIGHT. WEAK LOW PRESSURE
DEVELOPS OFF OF THE CAROLINA COAST THURSDAY.
&&
.NEAR TERM /THROUGH TODAY/...
AS OF 255 AM TUESDAY...
THE SURFACE COLD FRONT CONTINUES TO MAKE GRADUAL EASTWARD PROGRESS
OFFSHORE OF THE CAROLINAS...THOUGH WEAK SURFACE CYCLONIC FLOW
CONTINUES ON THE LATEST SURFACE ANALYSIS OVER THE SOUTHEAST PART OF
THE STATE. PATCHES OF LIGHT RAIN PERSISTED THERE UNDERNEATH THE
SOUTHWEST FLOW ALOFT...BUT DURING THE MORNING THE MORE MOIST FLOW
ALOFT WILL ALSO SHIFT EAST AS THE UPPER TROUGH ON WATER VAPOR...
MOVING INTO THE TENNESSEE VALLEY...MOVES INTO AND THEN ACROSS THE
STATE. THE HRRR WRF HAS BEEN CONSISTENT WITH ITSELF...AND WITH THE
DIMINISHING MOISTURE NOTED ON GFS BUFR SOUNDINGS...THAT MUCH OF THE
PATCHY LIGHT RAIN SHOULD BE MOVING OFF TO THE EAST OF CENTRAL NORTH
CAROLINA BY AROUND 12Z. WILL RETAIN A SLIGHT CHANCE OF RAIN EAST OF
INTERSTATE 95 FOR THE EARLY DAYLIGHT HOURS...THEN WILL SHOW DRY
CONDITIONS FOR THE REST OF THE DAY WITH CHANCES LESS THAN SLIGHT.
EVEN THOUGH THE UPPER TROUGH IS WELL DEFINED ON WATER VAPOR
IMAGERY...THE GUIDANCE CONSENSUS IS DRIER THAN 24 HOURS AGO...MAKING
THE CHANCES FOR SPRINKLES WITH THE APPROACH OF THE TROUGH ALOFT
REMOTE. TOO MUCH MID-LEVEL DRY AIR IS FORECAST...COINCIDENT WITH DRY
AIR TO OUR WEST AS NOTED ON THE 00Z UPPER-AIR ANALYSIS. EVEN THE
TREND IS DRIER IN THE LOWER LEVELS...THOUGH EXPECT LINGERING
STRATOCU INTO THE MORNING IN MANY AREAS.
THE SURFACE GRADIENT TIGHTENS TODAY AS HIGH PRESSURE BUILDS IN
BEHIND THE DEPARTING FRONT. BUFR SOUNDINGS SUGGEST ENOUGH MIXING
THAT FOR A PERIOD THIS AFTERNOON WIND GUSTS SHOULD REACH INTO THE
UPPER TEENS TO LOWER 20S KNOTS...WITH NORTHERLY WINDS BACKING MORE
NORTHWEST WITH MIXING. 1000-850MB THICKNESSES WILL BE FALLING DURING
THE DAY...BUT THEIR VALUES SUGGEST HIGHS CLOSE TO MOS GUIDANCE BUT
WITH ONLY MINIMAL RECOVERY FROM LATE NIGHT TEMPERATURES...FOR HIGHS
IN THE MID 40S TO AROUND 50.
&&
.SHORT TERM /TONIGHT THROUGH WEDNESDAY NIGHT/...
AS OF 255 AM TUESDAY...
HIGH PRESSURE REMAINS FOR MUCH OF THIS PERIOD...WITH PRECIPITABLE
WATER VALUES MOSTLY BELOW A QUARTER-INCH AND K INDICES HIGHLY
NEGATIVE. DRY SURFACE DEW POINTS MOVE IN AS WELL. BUFR SOUNDINGS AND
RELATIVE HUMIDITY FORECASTS ARE DRY...SUGGESTIVE OF CLEAR OR MOSTLY
CLEAR CONDITIONS INTO WEDNESDAY NIGHT. LOWS TONIGHT IN THE
20S...WITH HIGHS WEDNESDAY IN THE LOWER TO MID 40S...NEARER THE
SLIGHTLY WARMER MAV MOS GUIDANCE WHICH IS CLOSER TO EXPECTED VALUES
BASED ON 1000-850MB THICKNESSES.
WEDNESDAY NIGHT...THERE IS SOME GUIDANCE DIFFERENCE ON THE AMOUNT OF
HIGH CLOUDS THAT COULD MOVE INTO CENTRAL NORTH CAROLINA WITH THE
APPROACH OF A JET AXIS ALOFT...AND LOWERING HEIGHTS. THE NAM IS
CERTAINLY DRIER THAN THE GFS...WHICH IS DEEPER WITH THE ENERGY ALOFT
AND LOWERS PRESSURES MORE OFF OF THE CAROLINA COAST BY 12Z THURSDAY.
THE 00Z ECMWF OFFERS A GOOD COMPROMISE...SHOWING A FEW HIGH CLOUDS
STARTING TO ENCROACH ON CENTRAL NORTH CAROLINA FROM THE SOUTH LATE
IN THE DAY WEDNESDAY...AND SLOWLY SPREADING NORTH OVER MUCH OF THE
AREA WEDNESDAY NIGHT...LIKELY MORE OPAQUE SOUTH. WILL GO CLOSER TO
THE COLDER MET GUIDANCE WEDNESDAY NIGHT IN THE TRIAD AND NEAR THE
VIRGINIA BORDER...WITH A BLEND IN THE MIDDLE INCLUDING THE TRIANGLE
AND KRWI...AND CLOSER TO THE WARMER MAV GUIDANCE TOWARD KFAY. THIS
RESULTS IN LOWS IN THE LOWER 20S TOWARD KTDF...25 TO 30 OVER THE
SANDHILLS AND SOUTHERN COASTAL PLAIN...AND MID 20S IN BETWEEN.
&&
.LONG TERM /THURSDAY THROUGH MONDAY/...
AS OF 300 AM TUESDAY...
A SOUTHERN STREAM WAVE WILL TRACK ACROSS THE SOUTHEAST ON
THURSDAY...WITH A NORTHERN STREAM CLIPPER ON ITS HEELS. MODELS
INDICATE A WEAK SURFACE LOW MAY DEVELOP OFF THE NC/SC COAST IN
RESPONSE TO THE WEAK DPVA AND UPPER DIVERGENCE IN THE RIGHT FRONT
ENTRANCE REGION OF AN INTENSIFYING UPPER JET OVER THE MID-ATLANTIC
STATES. HOWEVER...FORECAST SOUNDINGS SHOW LIMITED MID-LEVEL
MOISTURE INLAND AND THUS DONT PRODUCE ANY QPF OVER THE RAH CWA.
CIRRUS SHOULD BE RATHER ABUNDANT...AT LEAST EARLY IN THE
DAY...BEFORE BEING SHUNTED EASTWARD WITH THE PASSING NORTHERN STREAM
TROUGH AXIS. THIS WILL LIMIT SOME OF THE MODERATION OF
TEMPS....THOUGH HIGHS SHOULD STILL REACH SEASONAL NORMS...48-52.
LOWS THURSDAY NIGHT 26-31.
THE REMAINDER OF THE EXTENDED PERIOD WILL BE MOSTLY DOMINATED BY THE
NORTHERN STREAM AS SHORTWAVES MOVING ACROSS THE GREAT LAKES REGION
SLOWLY CARVE OUT A LONGWAVE TROUGH OVER THE EASTERN US. THIS IS
SUPPORTED BY A TREND TOWARD NEGATIVE NAO/AO PHASES IN THE MEDIUM
RANGE. ANOTHER SOUTHERN STREAM SHORTWAVE AND ASSOCIATED POTENTIAL
SURFACE LOW SHOULD REMAINED SUPPRESSED OFFSHORE
SUNDAY/MONDAY...THOUGH THE 00Z ECMWF TRENDED FURTHER WEST WITH
MOISTURE ON SUNDAY. WILL LEAVE THE FORECAST DRY AT THIS TIME.
PERIODS OF CIRRUS WILL LIKELY PLAGUE THE AREA OVER THE
WEEKEND...WITH HIGHS REBOUNDING A BIT...INTO THE LOW TO MID 50S...
BEFORE WHAT APPEARS TO BE A MOSTLY DRY COLD FRONT CROSSES THE AREA
EARLY NEXT WEEK.
&&
.AVIATION /06Z TUESDAY THROUGH SATURDAY/...
AS OF 1250 AM TUESDAY...
VFR CONDITIONS OVER THE WESTERN PIEDMONT...INCLUDING THE TRIAD...
WILL GRADUALLY SPREAD EAST OVER CENTRAL NORTH CAROLINA DURING THIS
EARLY MORNING...WITH KRWI LIKELY THE LAST TAF SITE TO BECOME VFR
AROUND 12Z...COINCIDENT WITH AREAS OF LIGHT RAIN MOVING OFF TO THE
EAST. WHILE THE NAM MODEL DRIES OUT THE LOW LEVELS FASTER THAN THE
GFS...EVEN THE GFS WOULD SUGGEST BROKEN VFR-LEVEL CEILINGS ENDING BY
AFTERNOON. WITH MIXING TODAY...WINDS SHOULD BACK MORE TO THE
NORTHWEST WITH GUSTS IN THE 20S KNOTS AS THE SURFACE GRADIENT
TIGHTENS. WINDS WILL DIMINISH THIS EVENING AS HIGH PRESSURE
CONTINUES TO BUILD OVER THE AREA.
BEYOND THE 06Z VALID TAF PERIOD...EXPECT VFR CONDITIONS. BASED ON
THE LATEST GFS MODEL GUIDANCE...THERE IS A LOW PROBABILITY OF SUB-
VFR CONDITIONS AT KFAY AND KRWI LATE WEDNESDAY NIGHT INTO EARLY
THURSDAY AS WEAK LOW PRESSURE DEVELOPS OFF OF THE CAROLINA COAST.
OTHER GUIDANCE APPEARS DRIER AS OF THIS WRITING.
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...DJF
NEAR TERM...DJF
SHORT TERM...DJF
LONG TERM...SMITH
AVIATION...DJF
AREA FORECAST DISCUSSION
NWS RALEIGH NC
256 AM EST TUE DEC 24 2013
.SYNOPSIS...BEHIND A COLD FRONT MOVING OFF OF THE CAROLINA COAST
THROUGH EARLY AFTERNOON...HIGH PRESSURE BUILDS OVER THE REGION. HIGH
PRESSURE REMAINS AT LEAST THROUGH CHRISTMAS NIGHT. WEAK LOW PRESSURE
DEVELOPS OFF OF THE CAROLINA COAST THURSDAY.
&&
.NEAR TERM /THROUGH TODAY/...
AS OF 255 AM TUESDAY...
THE SURFACE COLD FRONT CONTINUES TO MAKE GRADUAL EASTWARD PROGRESS
OFFSHORE OF THE CAROLINAS...THOUGH WEAK SURFACE CYCLONIC FLOW
CONTINUES ON THE LATEST SURFACE ANALYSIS OVER THE SOUTHEAST PART OF
THE STATE. PATCHES OF LIGHT RAIN PERSISTED THERE UNDERNEATH THE
SOUTHWEST FLOW ALOFT...BUT DURING THE MORNING THE MORE MOIST FLOW
ALOFT WILL ALSO SHIFT EAST AS THE UPPER TROUGH ON WATER VAPOR...
MOVING INTO THE TENNESSEE VALLEY...MOVES INTO AND THEN ACROSS THE
STATE. THE HRRR WRF HAS BEEN CONSISTENT WITH ITSELF...AND WITH THE
DIMINISHING MOISTURE NOTED ON GFS BUFR SOUNDINGS...THAT MUCH OF THE
PATCHY LIGHT RAIN SHOULD BE MOVING OFF TO THE EAST OF CENTRAL NORTH
CAROLINA BY AROUND 12Z. WILL RETAIN A SLIGHT CHANCE OF RAIN EAST OF
INTERSTATE 95 FOR THE EARLY DAYLIGHT HOURS...THEN WILL SHOW DRY
CONDITIONS FOR THE REST OF THE DAY WITH CHANCES LESS THAN SLIGHT.
EVEN THOUGH THE UPPER TROUGH IS WELL DEFINED ON WATER VAPOR
IMAGERY...THE GUIDANCE CONSENSUS IS DRIER THAN 24 HOURS AGO...MAKING
THE CHANCES FOR SPRINKLES WITH THE APPROACH OF THE TROUGH ALOFT
REMOTE. TOO MUCH MID-LEVEL DRY AIR IS FORECAST...COINCIDENT WITH DRY
AIR TO OUR WEST AS NOTED ON THE 00Z UPPER-AIR ANALYSIS. EVEN THE
TREND IS DRIER IN THE LOWER LEVELS...THOUGH EXPECT LINGERING
STRATOCU INTO THE MORNING IN MANY AREAS.
THE SURFACE GRADIENT TIGHTENS TODAY AS HIGH PRESSURE BUILDS IN
BEHIND THE DEPARTING FRONT. BUFR SOUNDINGS SUGGEST ENOUGH MIXING
THAT FOR A PERIOD THIS AFTERNOON WIND GUSTS SHOULD REACH INTO THE
UPPER TEENS TO LOWER 20S KNOTS...WITH NORTHERLY WINDS BACKING MORE
NORTHWEST WITH MIXING. 1000-850MB THICKNESSES WILL BE FALLING DURING
THE DAY...BUT THEIR VALUES SUGGEST HIGHS CLOSE TO MOS GUIDANCE BUT
WITH ONLY MINIMAL RECOVERY FROM LATE NIGHT TEMPERATURES...FOR HIGHS
IN THE MID 40S TO AROUND 50.
&&
.SHORT TERM /TONIGHT THROUGH WEDNESDAY NIGHT/...
AS OF 255 AM TUESDAY...
HIGH PRESSURE REMAINS FOR MUCH OF THIS PERIOD...WITH PRECIPITABLE
WATER VALUES MOSTLY BELOW A QUARTER-INCH AND K INDICES HIGHLY
NEGATIVE. DRY SURFACE DEW POINTS MOVE IN AS WELL. BUFR SOUNDINGS AND
RELATIVE HUMIDITY FORECASTS ARE DRY...SUGGESTIVE OF CLEAR OR MOSTLY
CLEAR CONDITIONS INTO WEDNESDAY NIGHT. LOWS TONIGHT IN THE
20S...WITH HIGHS WEDNESDAY IN THE LOWER TO MID 40S...NEARER THE
SLIGHTLY WARMER MAV MOS GUIDANCE WHICH IS CLOSER TO EXPECTED VALUES
BASED ON 1000-850MB THICKNESSES.
WEDNESDAY NIGHT...THERE IS SOME GUIDANCE DIFFERENCE ON THE AMOUNT OF
HIGH CLOUDS THAT COULD MOVE INTO CENTRAL NORTH CAROLINA WITH THE
APPROACH OF A JET AXIS ALOFT...AND LOWERING HEIGHTS. THE NAM IS
CERTAINLY DRIER THAN THE GFS...WHICH IS DEEPER WITH THE ENERGY ALOFT
AND LOWERS PRESSURES MORE OFF OF THE CAROLINA COAST BY 12Z THURSDAY.
THE 00Z ECMWF OFFERS A GOOD COMPROMISE...SHOWING A FEW HIGH CLOUDS
STARTING TO ENCROACH ON CENTRAL NORTH CAROLINA FROM THE SOUTH LATE
IN THE DAY WEDNESDAY...AND SLOWLY SPREADING NORTH OVER MUCH OF THE
AREA WEDNESDAY NIGHT...LIKELY MORE OPAQUE SOUTH. WILL GO CLOSER TO
THE COLDER MET GUIDANCE WEDNESDAY NIGHT IN THE TRIAD AND NEAR THE
VIRGINIA BORDER...WITH A BLEND IN THE MIDDLE INCLUDING THE TRIANGLE
AND KRWI...AND CLOSER TO THE WARMER MAV GUIDANCE TOWARD KFAY. THIS
RESULTS IN LOWS IN THE LOWER 20S TOWARD KTDF...25 TO 30 OVER THE
SANDHILLS AND SOUTHERN COASTAL PLAIN...AND MID 20S IN BETWEEN.
&&
.LONG TERM /THURSDAY THROUGH MONDAY/...
AS OF 110 PM MONDAY...
ON THURSDAY...A SOUTHERN STREAM WAVE OVER NRN FL AND SRN GA EARLY IN
THE DAY WILL MOVE NE ALONG THE COAST...EXITING NE OF THE CAROLINAS
BY MID-EVENING. LATEST MODEL RUNS NOW SUGGEST THE BEST MOISTURE WILL
REMAIN WELL EAST OF I-95...SO WITH THIS FORECAST CYCLE WILL LIKELY
KEEP POPS BELOW 15 PERCENT FOR OUR EASTERN ZONES FOR THURSDAY. HIGHS
THURSDAY IN THE MID-UPR 40S.
THEREAFTER...HIGH PRESSURE WILL BUILD BACK OVER OUR REGION THURSDAY
NIGHT AND REMAIN OVER US THROUGH EARLY SUNDAY...RESULTING IN FAIR
WEATHER AND TEMPS NEAR TO SLIGHTLY BELOW NORMAL. DURING THE DAY
SUNDAY...THE HIGH WILL MOVE EAST AS THE NEXT COLD FRONT APPROACHES
FROM THE WEST LATE IN THE DAY. LOOK FOR TEMPS TO CLIMB TO A FEW
DEGREES ABOVE NORMAL ON SUNDAY AS THE RETURN FLOW SETS UP BEHIND THE
DEPARTING HIGH. OTHERWISE...CLOUDS WILL SLOWLY INCREASE DURING THE
DAY SUNDAY AS THE FRONT APPROACHES...BUT ANY RAIN WITH THE FRONT
SHOULD HOLD OFF UNTIL FROPA ON MONDAY.
&&
.AVIATION /06Z TUESDAY THROUGH SATURDAY/...
AS OF 1250 AM TUESDAY...
VFR CONDITIONS OVER THE WESTERN PIEDMONT...INCLUDING THE TRIAD...
WILL GRADUALLY SPREAD EAST OVER CENTRAL NORTH CAROLINA DURING THIS
EARLY MORNING...WITH KRWI LIKELY THE LAST TAF SITE TO BECOME VFR
AROUND 12Z...COINCIDENT WITH AREAS OF LIGHT RAIN MOVING OFF TO THE
EAST. WHILE THE NAM MODEL DRIES OUT THE LOW LEVELS FASTER THAN THE
GFS...EVEN THE GFS WOULD SUGGEST BROKEN VFR-LEVEL CEILINGS ENDING BY
AFTERNOON. WITH MIXING TODAY...WINDS SHOULD BACK MORE TO THE
NORTHWEST WITH GUSTS IN THE 20S KNOTS AS THE SURFACE GRADIENT
TIGHTENS. WINDS WILL DIMINISH THIS EVENING AS HIGH PRESSURE
CONTINUES TO BUILD OVER THE AREA.
BEYOND THE 06Z VALID TAF PERIOD...EXPECT VFR CONDITIONS. BASED ON
THE LATEST GFS MODEL GUIDANCE...THERE IS A LOW PROBABILITY OF SUB-
VFR CONDITIONS AT KFAY AND KRWI LATE WEDNESDAY NIGHT INTO EARLY
THURSDAY AS WEAK LOW PRESSURE DEVELOPS OFF OF THE CAROLINA COAST.
OTHER GUIDANCE APPEARS DRIER AS OF THIS WRITING.
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...DJF
NEAR TERM...DJF
SHORT TERM...DJF
LONG TERM...NP
AVIATION...DJF
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
1232 AM EST TUE DEC 24 2013
.SYNOPSIS...
A SLOW MOVING COLD FRONT APPROACHING FROM THE WEST WILL MOVE OFF THE
COAST TONIGHT. DRIER AND COOLER AIR WILL SPREAD ACROSS THE REGION IN
THE WAKE OF THE COLD FRONT. A MOSTLY DRY COLD FRONT WILL PASS ACROSS
THE AREA FRIDAY...MAINTAINING SEASONABLE TEMPERATURES INTO THE
WEEKEND.
&&
.NEAR TERM /UNTIL 6 AM TUESDAY MORNING/...
AS OF 1015 PM MONDAY...THE SFC COLD FRONT HAS BEEN MAKING PROGRESS
TO THE SOUTHEAST THIS EVENING...AND NOW EXTENDS ACROSS THE EASTERN
CAROLINAS...HAVING PUSHED EAST OF THE I-95 CORRIDOR. THE COLD
FRONT WILL PUSH ACROSS THE REMAINING PORTIONS OF THE FA LATE THIS
EVENING OR EARLY ON DURING THE PRE-DAWN TUE HOURS. THE POST COLD
FRONTAL SENSIBLE WX CONDITIONS ACROSS THE FA WILL EXPERIENCE A WIND
DIRECTION CHANGE VEERING TO THE NW-N AT 5 TO 15 MPH...COLD AIR
ADVECTION ACCOMPANIED BY LOWER DEWPOINTS. LATEST PROGS CONTINUE
WITH POST-FRONTAL LIGHT RAIN AND SHOWERS PERSISTING OVERNIGHT INTO
DAYLIGHT TUESDAY B4 FINALLY BEING PUSHED OFF THE COAST AND
OFFSHORE FROM A PROGRESSIVE UPPER S/W TROF. OVERNITE LOWS HAVE
BEEN TWEAKED...WITH MINS OCCURRING AROUND SUNRISE TUESDAY.
&&
.SHORT TERM /6 AM TUESDAY MORNING THROUGH WEDNESDAY NIGHT/...
AS OF 240 PM MONDAY...A DRIER COLUMN WILL BUILD ACROSS THE AREA
EARLY ON IN THE SHORT TERM PERIOD AS THE SUBTROPICAL MOISTURE
PLUME SHIFTS AWAY FROM THE COAST. LINGERING LOW CLOUDS IN THE
MORNING...BUT RAINFALL WILL COME TO AN END WITH THE DEPARTURE OF
THE AFOREMENTIONED PLUME AND AS STRONG SUBSIDENCE DEVELOPS IN THE
H85-H5 LAYER. THUS THE TREND FOR TUESDAY IS CLEARING SKIES AND
MUCH COOLER TEMPERATURES COMPARED TO THE RECENT WARM SPELL. COLDER
AIR ARRIVES TUESDAY NIGHT INTO WEDNESDAY MORNING (LOWS IN THE MID
TO UPPER 20S) WITH COLD AIR ADVECTION LEADING TO HIGHS ONLY IN THE
40S FOR CHRISTMAS DAY. INCREASING CLOUDS WEDNESDAY NIGHT WILL
RESULT IN SLIGHTLY WARMER MINS...BUT THEY WILL STILL BE AT OR JUST
BELOW FREEZING ACROSS THE FORECAST AREA.
&&
.LONG TERM /THURSDAY THROUGH MONDAY/...
AS OF 240 PM MONDAY...THE EXTENDED FORECAST CONTINUES TO LOOK RATHER
UNEVENTFUL WITH THE OVERALL MID LEVEL PATTERN DEPICTING A MODEST
TROUGH OVER THE EASTERN THIRD OF THE U.S. AND MODEST RIDGING ACROSS
THE SOUTHWEST. AT THE SURFACE THERE WILL BE TWO FRONTS THAT MOVE
ACROSS THE AREA THAT WILL ONLY SERVE TO RESET ANY TEMPERATURE
MODIFICATION.
TEMPERATURES THURSDAY AND FRIDAY WILL BE SLIGHTLY BELOW CLIMATOLOGY
AS THE COLD AIR MASS THAT FOLLOWS THE SYSTEM MOVING THROUGH TODAY
AND TONIGHT LINGERS. THERE IS A SLIGHT MODIFICATION OF TEMPERATURES
SATURDAY AND SUNDAY VIA AIRMASS MODIFICATION. THIS BRIEF WARMUP IS
SHORT LIVED AS ANOTHER DRY FRONT MOVES ACROSS MONDAY. THE TRENDS ARE
RATHER CONSISTENT AND THE CONSOLATION IS THAT THE WILD TEMPERATURE
SWINGS WE HAVE EXPERIENCED THE PAST FEW WEEKS ARE AT LEAST
TEMPORARILY A THING OF THE PAST.
FINALLY THE ONLY POPS IN THE FORECAST ARE THURSDAY INTO EARLY FRIDAY
FROM WHAT APPEARS TO BE MORE OF A WEAK WAVE MOVING IN FROM THE
SOUTHWEST FLOW ALOFT THAT SKIRTS THE AREA. THE SURFACE COASTAL
TROUGH PATTERN SEEMS TO HAVE DISAPPEARED. REGARDLESS OF THE FORCING
MECHANISMS...POPS REMAIN LOW AND MOSTLY CONFINED TO THE COASTAL
AREAS.
&&
.AVIATION /06Z TUESDAY THROUGH SATURDAY/...
AS OF 06Z...A COLD FRONT HAS CLEARED ALL THE TERMINALS. KFLO/KMYR
SHOULD BE PREDOMINATELY MVFR DUE TO CIGS...BECOMING VFR IN THE
PRE-DAWN HOURS...THEN SCATTER OUT BY MID MORNING. THERE IS A HIGHER
POTENTIAL FOR IFR OR LOWER FLIGHT CONDITIONS AT THE COASTAL
TERMINALS. THESE CONDITIONS SHOULD RISE TO MVFR JUST AFTER
SUNRISE...THEN SCATTER OUT BY MID TO LATE MORNING. NW-N WINDS WILL
CONTINUE THROUGHOUT THE DAY...WITH OCCASIONAL GUSTS TO AROUND 20
KNOTS. VFR WITH LIGHT N WINDS AFTER SUNSET.
EXTENDED OUTLOOK...VFR THROUGH THE PERIOD.
&&
.MARINE...
NEAR TERM /THROUGH TONIGHT/...
AS OF 1030 PM MONDAY...SCA WILL CONTINUE FOR THE ILM NC WATERS
THROUGH 7 AM TUESDAY. SCEC HAS REPLACED THE SCA FOR THE ILM SC
WATERS...AND WILL REMAIN IN EFFECT THRU 7 AM TUESDAY.
SW-WSW AROUND 15 KT LATE THIS EVENING...WILL VEER TO THE NW
AROUND 15 KT IMMEDIATELY AFTER THE COLD FRONTAL PASSAGE...AND
FURTHER VEER TO THE NORTH AT 10-20 KT DURING THE PRE-DAWN TUE
HOURS. THE LATEST NAM AND HRRR WIND PROGS ILLUSTRATE THIS NICELY.
SIGNIFICANT SEAS WILL BE GOVERNED BY A 7 TO 8 SECOND PERIOD SSE
BORDERLINE SWELL...AND A 10 SECOND PERIOD SE GROUND SWELL.
COMBINED WITH LOCALLY PRODUCED WIND DRIVEN WAVES...SIGNIFICANT
SEAS WILL RANGE BETWEEN 3 AND 5 FT FOR THE ILM SC WATERS...AND
4 TO 7 FT ACROSS THE ILM NC WATERS. THE 7 FOOTERS WILL OCCUR
ACROSS THE OUTER WATERS OFF CAPE FEAR. AREAL COVERAGE OF SEA FOG
HAS DECREASED...AND WILL FURTHER DECREASE OVERNIGHT ESPECIALLY
ONCE THE POST FRONTAL LOWER DEWPOINTS ADVECT ACROSS THE LOCAL
WATERS.
SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/...
AS OF 240 PM MONDAY...N TO NW FLOW WILL PREVAIL IN THE WAKE OF THE
COLD FRONT TUESDAY AND TUESDAY NIGHT...THEN THE WIND WILL VEER TO
THE NE DURING WEDNESDAY. WINDS WILL DIMINISH TO AROUND 10 KT OR LESS
BY WEDNESDAY NIGHT AS WEAKENING RIDGE OF HIGH PRESSURE BUILD INTO
THE VICINITY. THE OFFSHORE TRAJECTORY WILL RESULT IN A RANGE OF SEAS
THAT WILL BE FETCH LIMITED NEAR THE COAST. FOR THE MOST PART SEAS
WILL APPROACH 5 FT CLOSER TO 20 NM OFFSHORE THROUGH MOST OF THE
PERIOD WITH 1-2 FT SEAS NEAR THE COAST.
LONG TERM /THURSDAY THROUGH SATURDAY/...
AS OF 240 PM MONDAY...ONCE AGAIN THE CENTRAL THEME FOR THE EXTENDED
COASTAL WATERS FORECAST IS A NORTHERLY COMPONENT TO THE WINDS. FOR
THURSDAY THE FLOW WILL BE 10-15 KNOTS WITH A COUPLE OF ROGUE GUSTS
OVER 15 POSSIBLE. AS A DRY FRONT MOVES ACROSS FRIDAY SPEEDS WILL
INCREASE TO 15-20 KNOTS. SATURDAY WINDS DROP BACK DOWN TO 10-15
KNOTS...AGAIN FROM THE NORTH. SEAS WILL FOLLOW THE WIND SPEED TRENDS
WITH 2-4 FEET THURSDAY AND SATURDAY WITH 3-5 FEET FOR FRIDAY.
&&
.ILM WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
NC...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 7 AM EST TUESDAY FOR AMZ250-252.
&&
$$
SYNOPSIS...SRP
NEAR TERM...DCH
SHORT TERM...SRP
LONG TERM...SHK
AVIATION...MRR/RJD
AREA FORECAST DISCUSSION...UPDATED
NWS GRAND FORKS ND
112 PM CST TUE DEC 24 2013
.UPDATE...
ISSUED AT 112 PM CST TUE DEC 24 2013
BACK EDGE OF SNOW BAND NOW EXTENDS FROM NEAR BAUDETTE TO FARGO TO
LISBON...MOVING TO THE EAST-SOUTHEAST AROUND 25 MPH. WILL ALLOW
THE NORTHERN VALLEY PORTION OF THE ADVISORY TO EXPIRE AT 1 PM AND
WILL ALSO CANCEL THE WESTERN TIER OF COUNTIES FOR THE PORTION SET
TO EXPIRE AT 7 PM. RADAR REFLECTIVITY HAS DIMINISHED ACROSS MUCH
OF THE FORECAST AREA WITH THE HIGHER RETURNS/HEAVIER SNOW
COAGULATING ACROSS NORTHEAST SD ALONG TRACK OF 850 HPA LOW. SNOW
AMOUNTS ACROSS NORTHWEST AND WEST CENTRAL MN LIKELY TO BE ON THE
LOW END OF PREVIOUSLY FORECAST RANGE (1-2 INCHES)...BUT WILL
MAINTAIN ADVISORY GIVEN SOME BLOWING SNOW AND REDUCED VISIBLITY.
HOWEVER...LOCALIZED HIGHER POCKETS OF 3-4 INCHES STILL NOT OUT THE
QUESTION. MADE SOME MINOR ADJUSTMENTS TO THE REST OF THE GRIDS TO
FALL IN-LINE WITH CURRENT OBSERVATIONS. OTHERWISE...CURRENT
FORECAST LOOKS GOOD.
UPDATE ISSUED AT 1014 AM CST TUE DEC 24 2013
CONCERNS THIS MORNING INCLUDE SNOW/WIND AND ASSOCIATED ADVISORY
HEADLINES. WILL FOLLOW CURRENT OBSERVATIONS AND LATEST RAP/HRRR
OUTPUT FOR UPDATE DETAILS.
WSR-88D SHOWING A LINE OF LIGHT TO MODERATE SNOW FROM ROSEAU/
HALLOCK THROUGH GRAND FORKS/THIEF RIVER FALLS AND INTO SOUTHEAST
ND. STRONGEST WIND IS CONFINED MAINLY TO THE NORTHERN VALLEY INTO
NORTHWEST MN WHERE RAP IS SHOWING 925 HPA WINDS AROUND 50 KTS.
VERY STRONG INVERSION IS KEEPING MUCH OF THIS FROM MIXING TO THE
SURFACE...BUT STILL SEEING SOME OBSERVATIONS SUSTAINED AROUND 20
MPH WITH GUSTS TO 25 MPH. THESE WINDS...COMBINED WITH SNOW IS
RESULTING IN SOME REDUCTION IN VISIBILITY BETWEEN 1/4 AND 1/2 MILE.
WITH THIS IN MIND AND GIVEN THE BUSY TRAVEL DAY BEFORE CHRISTMAS...
CURRENT ADVISORY LOOKS GOOD. TOTAL SNOW ACCUMULATION FROM 1 TO 4
INCHES IS STILL REASONABLE WITH THE HIGHER AMOUNTS ALONG THE ND/SD
BORDER INTO WEST CENTRAL MN COINCIDENT WITH 850 HPA LOW TRACK. DID
ADD RANSOM/SARGENT COUNTIES TO THE ADVISORY UNTIL 01 UTC AS THERE
IS AN AREA OF LIGHT TO MODERATE SNOW MAKING ITS WAY THROUGH LAMOURE/
DICKEY COUNTIES. WINDS NOT AS STRONG IN THIS AREA...BUT A QUICK 2
TO 4 INCHES OF FRESH SNOW ARE POSSIBLE.
A WELL-DEFINED BACK EDGE OF THE SNOW HAS DEVELOPED FROM HALLOCK TO
COOPERSTOWN TO JAMESTOWN...SO MAY BE ABLE TO CANCEL PORTIONS OF
THE ADVISORY AT THE 1 PM UPDATE. FOR NOW...UPDATED POPS TO REMOVE
ALL SNOW MENTION ACROSS THE DEVILS LAKE BASIN. ALL OTHER GRIDS
GOOD WITH ONLY SMALL ADJUSTMENTS TO ACCOUNT FOR LATEST
OBSERVATIONS.
UPDATE ISSUED AT 651 AM CST TUE DEC 24 2013
CURRENT RADAR IMAGERY INDICATES AN AREA OF HEAVIER PRECIP ACROSS
NORTHWEST SOUTH DAKOTA (LIKELY ASSOCIATED WITH STRONGER FORCING
FROM UPPER WAVE)...AND A BAND OF PRECIP EXTENDING TO THE NORTH
(LIKELY ASSOCIATED WITH 850MB WARM AIR ADVECTION). THE WARM AIR
ADVECTION SNOWFALL SHOULD LEAD TO MOSTLY 1-2 INCHES...POSSIBLY UP
TO 3. THE SOUTHERN AND HEAVIER AREA OF PRECIP WILL LIKELY LEAD TO
2-4 INCHES...POSSIBLY UP TO 5. THE MAIN QUESTION IS WHERE WILL
THIS STRONGER AREA OF PRECIP TRACK. THE RAP INITIALIZED THIS AREA
TOO FAR NORTH...AND WILL THROW OUT THIS SOLUTION. THE REMAINDER OF
THE GUIDANCE HAS COME INTO SOME SORT OF AGREEMENT...INDICATING
ACROSS THE SOUTHERN VALLEY AND INTO THE WADENA AREA. SLIGHTLY ADJUSTED
THE SNOWFALL FORECAST TO ACCOUNT FOR THE ABOVE THINKING...MOSTLY
LIMITING THE 3+ TOTALS ALONG AND SOUTH OF A LIDGERWOOD TO PARK
RAPIDS LINE. THE ONLY CHANGE MADE TO THE WINTER WEATHER ADVISORY
WAS TO END THE NORTHERN VALLEY AT 19Z AS IT APPEARS SNOW WILL BE
OVER BY THIS TIME. THE ADVISORY LOOKS GOOD FOR AREAS ACROSS THE
SOUTH EXPECTED TO RECEIVE 3+ INCHES OF SNOW. TO THE NORTH...1-3
INCHES OF SNOW NOT REALLY ADVISORY CRITERIA...AND WINDS ARE NOT
QUITE STRONG ENOUGH TO CAUSE BLOWING SNOW. HOWEVER...GIVEN THE
20-30 MPH WINDS COMBINED WITH HIGHER SNOWFALL RATES...WILL LET IT
RIDE (THIS WILL CAUSE SOME TRAVEL HAZARDS).
&&
.SHORT TERM...(TODAY THROUGH WEDNESDAY)
ISSUED AT 345 AM CST TUE DEC 24 2013
THE MAIN CONCERN WILL BE WIND SPEEDS AND SNOW AMOUNTS TODAY. 00Z
MODELS ARE IN POOR AGREEMENT...MAKING CONFIDENCE WITH DETAILS
QUITE LOW. THE ECMWF IS THE FURTHEST SOUTH WITH THE HEAVIEST BAND
OF SNOWFALL (JUST SOUTH OF THE FA)...WHILE THE
GFS/NAM/GEM/RAP/HRRR BRING THE HEAVIER BAND THROUGH THE SOUTHERN
FA (WITH LIGHTER AMOUNTS TO THE NORTH). THE HIGH-RES GUIDANCE IS
INDICATING QPF AROUND 0.40 INCHES WITHIN THE HEAVIER BAND (AND
AROUND 0.10 INCHES ELSEWHERE)...WHICH WOULD EQUATE TO 4-6 INCHES.
THE 06Z NAM HAS TRENDED FURTHER SOUTH...AND CURRENT RADAR IMAGERY
SEEMS TO SUPPORT THE SOUTHERN SOLUTION. GIVEN THE LOW
CONFIDENCE...WILL MONITOR OBSERVATIONAL TRENDS AND INCOMING MODEL
GUIDANCE OVER THE NEXT FEW HOURS BEFORE MAKING ANY RADICAL CHANGES
TO THE FORECAST...AND STICK TO THE ONGOING FORECAST UNTIL THEN.
THE ONLY CHANGE WAS TO DELAY THE ONSET OF SNOWFALL THIS MORNING.
LATEST GUIDANCE IS INDICATING COLDER TEMPERATURES FOR TODAY...AND
SHALLOWER MIXING POTENTIAL. THIS MEANS WINDS MAY NOT BE QUITE AS
STRONG...BUT STILL LIKELY 20-30MPH THIS MORNING (WHICH COMBINED
WITH FALLING SNOW COULD STILL LEAD TO POOR VISIBILITY).
TONIGHT-WEDNESDAY...EXPECT NORTHWEST FLOW ALOFT...ALONG WITH HARD
TO TIME UPPER WAVES. MOST GUIDANCE INDICATES A WEAK WAVE TONIGHT
INTO WEDNESDAY MORNING...AND INCREASED POPS INTO THE 30%-40%
RANGE FOR THIS FEATURE. WINDS FROM THE NW COULD BE BREEZY AT TIMES
BEHIND THE UPPER WAVE...BUT SHOULD NOT BE STRONG ENOUGH FOR
DRIFTING AND/OR BLOWING SNOW.
.LONG TERM...(WEDNESDAY NIGHT THROUGH MONDAY)
ISSUED AT 345 AM CST TUE DEC 24 2013
WEDNESDAY NIGHT-THURSDAY NIGHT...NORTHWEST FLOW ALOFT...ALONG WITH
HARD TO TIME SHORTWAVES...WILL CONTINUE. MOST GUIDANCE AGREES ON
THE NEXT WAVE LATE WED NIGHT INTO THURSDAY...AND INCREASED POPS
INTO THE 30-40% RANGE FOR THIS FEATURE.
FRIDAY-MONDAY...FRIDAY LOOKS DOWNRIGHT BALMY COMPARED TO RECENT
DAYS AS RISING HEIGHTS AHEAD OF WEEKEND SYSTEM CAUSE BROAD
SOUTHWEST FLOW AT THE SURFACE. FRONTAL BOUNDARY/THERMAL RIBBON IS
NORTH OF CWFA ON FRIDAY. HOWEVER MID LEVEL MOISTURE AND LIFT
GENERATED BY EXIT REGION OF 300MB JET JUSTIFY LOW POPS SAGGING
INTO NORTHERN THIRD CWFA AFTER 00Z SATURDAY. BASED ON CURRENT AND
PREVIOUS GUIDANCE WILL CONTINUE TO SPREAD POPS SOUTH WITH
APPROACHING SHORT WAVE...INCREASING CYCLONIC FLOW AND LIFT IN LEFT
REAR QUAD OF JET.
00Z SUITE OF MODELS IN PRETTY GOOD AGREEMENT WITH THE TIMING OF THE
NEXT COLD SURGE. THE TEMPERATURE WILL PROBABLY PEAK EARLY SATURDAY
THEN BEGIN ANOTHER DOWNWARD SPIRAL BEHIND THE FRONT. SUBSIDENCE
BEHIND THE SHORTWAVE...MODEST PRESSURE RISE/FALL COUPLET...DEEP
LAYERED COLD ADVECTION AND ORIENTATION OF ISOBARS SUGGEST QUITE
BREEZY CONDITIONS POST FRONTAL FOR SATURDAY. HAVE UPPED WIND SPEEDS
ON SATURDAY INTO EVENING USING GFS/BCMOS BLEND.
BEYOND THAT THE LAST FEW DAYS OF 2013 ARE COLD AND DRY AS ARCTIC
RIDGE SLIDES ALONG AND WEST OF CWFA.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z WEDNESDAY AFTERNOON)
ISSUED AT 112 PM CST TUE DEC 24 2013
SNOW BAND ALONG A ROX-GFK-JMS LINE PROPAGATING EAST AT 25 KTS AND
USED THIS SPEED TO TIME BAND ACROSS FA. WILL BE LATE AFTERNOON WHEN
SNOW MOVES EAST OF ROUGHLY A KFAR-KFSE LINE AND EARLY EVENING FOR
THE REMAINDER OF THE FA. VSBY GENERALLY FROM 3/4 TO 2 MILES IN SNOW
BAND WITH GENERALLY MVFR CIGS. MORE MVFR CIGS DROPPING IN BEHIND
SNOW BAND SO WILL LIKELY BE THIS EVENING BEFORE CIGS LIFT INTO VFR
CONDITIONS.
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...WINTER WEATHER ADVISORY UNTIL 7 PM CST THIS EVENING FOR NDZ052-
053.
MN...WINTER WEATHER ADVISORY UNTIL 7 PM CST THIS EVENING FOR MNZ003-
006-009-016-017-022>024-027>032-040.
&&
$$
UPDATE...ROGERS
SHORT TERM...TG
LONG TERM...EWENS/TG
AVIATION...VOELKER
AREA FORECAST DISCUSSION...UPDATED
NWS GRAND FORKS ND
1014 AM CST TUE DEC 24 2013
.UPDATE...
ISSUED AT 1014 AM CST TUE DEC 24 2013
CONCERNS THIS MORNING INCLUDE SNOW/WIND AND ASSOCIATED ADVISORY
HEADLINES. WILL FOLLOW CURRENT OBSERVATIONS AND LATEST RAP/HRRR
OUTPUT FOR UPDATE DETAILS.
WSR-88D SHOWING A LINE OF LIGHT TO MODERATE SNOW FROM ROSEAU/
HALLOCK THROUGH GRAND FORKS/THIEF RIVER FALLS AND INTO SOUTHEAST
ND. STRONGEST WIND IS CONFINED MAINLY TO THE NORTHERN VALLEY INTO
NORTHWEST MN WHERE RAP IS SHOWING 925 HPA WINDS AROUND 50 KTS.
VERY STRONG INVERSION IS KEEPING MUCH OF THIS FROM MIXING TO THE
SURFACE...BUT STILL SEEING SOME OBSERVATIONS SUSTAINED AROUND 20
MPH WITH GUSTS TO 25 MPH. THESE WINDS...COMBINED WITH SNOW IS
RESULTING IN SOME REDUCTION IN VISIBILITY BETWEEN 1/4 AND 1/2 MILE.
WITH THIS IN MIND AND GIVEN THE BUSY TRAVEL DAY BEFORE CHRISTMAS...
CURRENT ADVISORY LOOKS GOOD. TOTAL SNOW ACCUMULATION FROM 1 TO 4
INCHES IS STILL REASONABLE WITH THE HIGHER AMOUNTS ALONG THE ND/SD
BORDER INTO WEST CENTRAL MN COINCIDENT WITH 850 HPA LOW TRACK. DID
ADD RANSOM/SARGENT COUNTIES TO THE ADVISORY UNTIL 01 UTC AS THERE
IS AN AREA OF LIGHT TO MODERATE SNOW MAKING ITS WAY THROUGH LAMOURE/
DICKEY COUNTIES. WINDS NOT AS STRONG IN THIS AREA...BUT A QUICK 2
TO 4 INCHES OF FRESH SNOW ARE POSSIBLE.
A WELL-DEFINED BACK EDGE OF THE SNOW HAS DEVELOPED FROM HALLOCK TO
COOPERSTOWN TO JAMESTOWN...SO MAY BE ABLE TO CANCEL PORTIONS OF
THE ADVISORY AT THE 1 PM UPDATE. FOR NOW...UPDATED POPS TO REMOVE
ALL SNOW MENTION ACROSS THE DEVILS LAKE BASIN. ALL OTHER GRIDS
GOOD WITH ONLY SMALL ADJUSTMENTS TO ACCOUNT FOR LATEST
OBSERVATIONS.
UPDATE ISSUED AT 651 AM CST TUE DEC 24 2013
CURRENT RADAR IMAGERY INDICATES AN AREA OF HEAVIER PRECIP ACROSS
NORTHWEST SOUTH DAKOTA (LIKELY ASSOCIATED WITH STRONGER FORCING
FROM UPPER WAVE)...AND A BAND OF PRECIP EXTENDING TO THE NORTH
(LIKELY ASSOCIATED WITH 850MB WARM AIR ADVECTION). THE WARM AIR
ADVECTION SNOWFALL SHOULD LEAD TO MOSTLY 1-2 INCHES...POSSIBLY UP
TO 3. THE SOUTHERN AND HEAVIER AREA OF PRECIP WILL LIKELY LEAD TO
2-4 INCHES...POSSIBLY UP TO 5. THE MAIN QUESTION IS WHERE WILL
THIS STRONGER AREA OF PRECIP TRACK. THE RAP INITIALIZED THIS AREA
TOO FAR NORTH...AND WILL THROW OUT THIS SOLUTION. THE REMAINDER OF
THE GUIDANCE HAS COME INTO SOME SORT OF AGREEMENT...INDICATING
ACROSS THE SOUTHERN VALLEY AND INTO THE WADENA AREA. SLIGHTLY ADJUSTED
THE SNOWFALL FORECAST TO ACCOUNT FOR THE ABOVE THINKING...MOSTLY
LIMITING THE 3+ TOTALS ALONG AND SOUTH OF A LIDGERWOOD TO PARK
RAPIDS LINE. THE ONLY CHANGE MADE TO THE WINTER WEATHER ADVISORY
WAS TO END THE NORTHERN VALLEY AT 19Z AS IT APPEARS SNOW WILL BE
OVER BY THIS TIME. THE ADVISORY LOOKS GOOD FOR AREAS ACROSS THE
SOUTH EXPECTED TO RECEIVE 3+ INCHES OF SNOW. TO THE NORTH...1-3
INCHES OF SNOW NOT REALLY ADVISORY CRITERIA...AND WINDS ARE NOT
QUITE STRONG ENOUGH TO CAUSE BLOWING SNOW. HOWEVER...GIVEN THE
20-30 MPH WINDS COMBINED WITH HIGHER SNOWFALL RATES...WILL LET IT
RIDE (THIS WILL CAUSE SOME TRAVEL HAZARDS).
&&
.SHORT TERM...(TODAY THROUGH WEDNESDAY)
ISSUED AT 345 AM CST TUE DEC 24 2013
THE MAIN CONCERN WILL BE WIND SPEEDS AND SNOW AMOUNTS TODAY. 00Z
MODELS ARE IN POOR AGREEMENT...MAKING CONFIDENCE WITH DETAILS
QUITE LOW. THE ECMWF IS THE FURTHEST SOUTH WITH THE HEAVIEST BAND
OF SNOWFALL (JUST SOUTH OF THE FA)...WHILE THE
GFS/NAM/GEM/RAP/HRRR BRING THE HEAVIER BAND THROUGH THE SOUTHERN
FA (WITH LIGHTER AMOUNTS TO THE NORTH). THE HIGH-RES GUIDANCE IS
INDICATING QPF AROUND 0.40 INCHES WITHIN THE HEAVIER BAND (AND
AROUND 0.10 INCHES ELSEWHERE)...WHICH WOULD EQUATE TO 4-6 INCHES.
THE 06Z NAM HAS TRENDED FURTHER SOUTH...AND CURRENT RADAR IMAGERY
SEEMS TO SUPPORT THE SOUTHERN SOLUTION. GIVEN THE LOW
CONFIDENCE...WILL MONITOR OBSERVATIONAL TRENDS AND INCOMING MODEL
GUIDANCE OVER THE NEXT FEW HOURS BEFORE MAKING ANY RADICAL CHANGES
TO THE FORECAST...AND STICK TO THE ONGOING FORECAST UNTIL THEN.
THE ONLY CHANGE WAS TO DELAY THE ONSET OF SNOWFALL THIS MORNING.
LATEST GUIDANCE IS INDICATING COLDER TEMPERATURES FOR TODAY...AND
SHALLOWER MIXING POTENTIAL. THIS MEANS WINDS MAY NOT BE QUITE AS
STRONG...BUT STILL LIKELY 20-30MPH THIS MORNING (WHICH COMBINED
WITH FALLING SNOW COULD STILL LEAD TO POOR VISIBILITY).
TONIGHT-WEDNESDAY...EXPECT NORTHWEST FLOW ALOFT...ALONG WITH HARD
TO TIME UPPER WAVES. MOST GUIDANCE INDICATES A WEAK WAVE TONIGHT
INTO WEDNESDAY MORNING...AND INCREASED POPS INTO THE 30%-40%
RANGE FOR THIS FEATURE. WINDS FROM THE NW COULD BE BREEZY AT TIMES
BEHIND THE UPPER WAVE...BUT SHOULD NOT BE STRONG ENOUGH FOR
DRIFTING AND/OR BLOWING SNOW.
.LONG TERM...(WEDNESDAY NIGHT THROUGH MONDAY)
ISSUED AT 345 AM CST TUE DEC 24 2013
WEDNESDAY NIGHT-THURSDAY NIGHT...NORTHWEST FLOW ALOFT...ALONG WITH
HARD TO TIME SHORTWAVES...WILL CONTINUE. MOST GUIDANCE AGREES ON
THE NEXT WAVE LATE WED NIGHT INTO THURSDAY...AND INCREASED POPS
INTO THE 30-40% RANGE FOR THIS FEATURE.
FRIDAY-MONDAY...FRIDAY LOOKS DOWNRIGHT BALMY COMPARED TO RECENT
DAYS AS RISING HEIGHTS AHEAD OF WEEKEND SYSTEM CAUSE BROAD
SOUTHWEST FLOW AT THE SURFACE. FRONTAL BOUNDARY/THERMAL RIBBON IS
NORTH OF CWFA ON FRIDAY. HOWEVER MID LEVEL MOISTURE AND LIFT
GENERATED BY EXIT REGION OF 300MB JET JUSTIFY LOW POPS SAGGING
INTO NORTHERN THIRD CWFA AFTER 00Z SATURDAY. BASED ON CURRENT AND
PREVIOUS GUIDANCE WILL CONTINUE TO SPREAD POPS SOUTH WITH
APPROACHING SHORT WAVE...INCREASING CYCLONIC FLOW AND LIFT IN LEFT
REAR QUAD OF JET.
00Z SUITE OF MODELS IN PRETTY GOOD AGREEMENT WITH THE TIMING OF THE
NEXT COLD SURGE. THE TEMPERATURE WILL PROBABLY PEAK EARLY SATURDAY
THEN BEGIN ANOTHER DOWNWARD SPIRAL BEHIND THE FRONT. SUBSIDENCE
BEHIND THE SHORTWAVE...MODEST PRESSURE RISE/FALL COUPLET...DEEP
LAYERED COLD ADVECTION AND ORIENTATION OF ISOBARS SUGGEST QUITE
BREEZY CONDITIONS POST FRONTAL FOR SATURDAY. HAVE UPPED WIND SPEEDS
ON SATURDAY INTO EVENING USING GFS/BCMOS BLEND.
BEYOND THAT THE LAST FEW DAYS OF 2013 ARE COLD AND DRY AS ARCTIC
RIDGE SLIDES ALONG AND WEST OF CWFA.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z WEDNESDAY MORNING)
ISSUED AT 651 AM CST TUE DEC 24 2013
THE MAIN CONCERN WILL BE SNOWFALL MOVING THROUGH THE REGION TODAY.
THIS REGION OF SNOWFALL WILL BE ASSOCIATED WITH MOSTLY MVFR
CIGS/VSBY...AND POSSIBLY PERIODS OF IFR CONDITIONS.
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...WINTER WEATHER ADVISORY UNTIL 7 PM CST THIS EVENING FOR NDZ039-
049-052-053.
WINTER WEATHER ADVISORY UNTIL 1 PM CST THIS AFTERNOON FOR NDZ008-
016-027-029-030.
MN...WINTER WEATHER ADVISORY UNTIL 7 PM CST THIS EVENING FOR MNZ002-
003-005-006-008-009-013>017-022>024-027>032-040.
WINTER WEATHER ADVISORY UNTIL 1 PM CST THIS AFTERNOON FOR MNZ001-
004-007.
&&
$$
UPDATE...ROGERS
SHORT TERM...TG
LONG TERM...EWENS/TG
AVIATION...TG
AREA FORECAST DISCUSSION
NWS GRAND FORKS ND
651 AM CST TUE DEC 24 2013
.UPDATE...
ISSUED AT 651 AM CST TUE DEC 24 2013
CURRENT RADAR IMAGERY INDICATES AN AREA OF HEAVIER PRECIP ACROSS
NORTHWEST SOUTH DAKOTA (LIKELY ASSOCIATED WITH STRONGER FORCING
FROM UPPER WAVE)...AND A BAND OF PRECIP EXTENDING TO THE NORTH
(LIKELY ASSOCIATED WITH 850MB WARM AIR ADVECTION). THE WARM AIR
ADVECTION SNOWFALL SHOULD LEAD TO MOSTLY 1-2 INCHES...POSSIBLY UP
TO 3. THE SOUTHERN AND HEAVIER AREA OF PRECIP WILL LIKELY LEAD TO
2-4 INCHES...POSSIBLY UP TO 5. THE MAIN QUESTION IS WHERE WILL
THIS STRONGER AREA OF PRECIP TRACK. THE RAP INITIALIZED THIS AREA
TOO FAR NORTH...AND WILL THROW OUT THIS SOLUTION. THE REMAINDER OF
THE GUIDANCE HAS COME INTO SOME SORT OF AGREEMENT...INDICATING
ACROSS THE SOUTHERN VALLEY AND INTO THE WADENA AREA. SLIGHTLY ADJUSTED
THE SNOWFALL FORECAST TO ACCOUNT FOR THE ABOVE THINKING...MOSTLY
LIMITING THE 3+ TOTALS ALONG AND SOUTH OF A LIDGERWOOD TO PARK
RAPIDS LINE. THE ONLY CHANGE MADE TO THE WINTER WEATHER ADVISORY
WAS TO END THE NORTHERN VALLEY AT 19Z AS IT APPEARS SNOW WILL BE
OVER BY THIS TIME. THE ADVISORY LOOKS GOOD FOR AREAS ACROSS THE
SOUTH EXPECTED TO RECEIVE 3+ INCHES OF SNOW. TO THE NORTH...1-3
INCHES OF SNOW NOT REALLY ADVISORY CRITERIA...AND WINDS ARE NOT
QUITE STRONG ENOUGH TO CAUSE BLOWING SNOW. HOWEVER...GIVEN THE
20-30 MPH WINDS COMBINED WITH HIGHER SNOWFALL RATES...WILL LET IT
RIDE (THIS WILL CAUSE SOME TRAVEL HAZARDS).
&&
.SHORT TERM...(TODAY THROUGH WEDNESDAY)
ISSUED AT 345 AM CST TUE DEC 24 2013
THE MAIN CONCERN WILL BE WIND SPEEDS AND SNOW AMOUNTS TODAY. 00Z
MODELS ARE IN POOR AGREEMENT...MAKING CONFIDENCE WITH DETAILS
QUITE LOW. THE ECMWF IS THE FURTHEST SOUTH WITH THE HEAVIEST BAND
OF SNOWFALL (JUST SOUTH OF THE FA)...WHILE THE
GFS/NAM/GEM/RAP/HRRR BRING THE HEAVIER BAND THROUGH THE SOUTHERN
FA (WITH LIGHTER AMOUNTS TO THE NORTH). THE HIGH-RES GUIDANCE IS
INDICATING QPF AROUND 0.40 INCHES WITHIN THE HEAVIER BAND (AND
AROUND 0.10 INCHES ELSEWHERE)...WHICH WOULD EQUATE TO 4-6 INCHES.
THE 06Z NAM HAS TRENDED FURTHER SOUTH...AND CURRENT RADAR IMAGERY
SEEMS TO SUPPORT THE SOUTHERN SOLUTION. GIVEN THE LOW
CONFIDENCE...WILL MONITOR OBSERVATIONAL TRENDS AND INCOMING MODEL
GUIDANCE OVER THE NEXT FEW HOURS BEFORE MAKING ANY RADICAL CHANGES
TO THE FORECAST...AND STICK TO THE ONGOING FORECAST UNTIL THEN.
THE ONLY CHANGE WAS TO DELAY THE ONSET OF SNOWFALL THIS MORNING.
LATEST GUIDANCE IS INDICATING COLDER TEMPERATURES FOR TODAY...AND
SHALLOWER MIXING POTENTIAL. THIS MEANS WINDS MAY NOT BE QUITE AS
STRONG...BUT STILL LIKELY 20-30MPH THIS MORNING (WHICH COMBINED
WITH FALLING SNOW COULD STILL LEAD TO POOR VISIBILITY).
TONIGHT-WEDNESDAY...EXPECT NORTHWEST FLOW ALOFT...ALONG WITH HARD
TO TIME UPPER WAVES. MOST GUIDANCE INDICATES A WEAK WAVE TONIGHT
INTO WEDNESDAY MORNING...AND INCREASED POPS INTO THE 30%-40%
RANGE FOR THIS FEATURE. WINDS FROM THE NW COULD BE BREEZY AT TIMES
BEHIND THE UPPER WAVE...BUT SHOULD NOT BE STRONG ENOUGH FOR
DRIFTING AND/OR BLOWING SNOW.
.LONG TERM...(WEDNESDAY NIGHT THROUGH MONDAY)
ISSUED AT 345 AM CST TUE DEC 24 2013
WEDNESDAY NIGHT-THURSDAY NIGHT...NORTHWEST FLOW ALOFT...ALONG WITH
HARD TO TIME SHORTWAVES...WILL CONTINUE. MOST GUIDANCE AGREES ON
THE NEXT WAVE LATE WED NIGHT INTO THURSDAY...AND INCREASED POPS
INTO THE 30-40% RANGE FOR THIS FEATURE.
FRIDAY-MONDAY...FRIDAY LOOKS DOWNRIGHT BALMY COMPARED TO RECENT
DAYS AS RISING HEIGHTS AHEAD OF WEEKEND SYSTEM CAUSE BROAD
SOUTHWEST FLOW AT THE SURFACE. FRONTAL BOUNDARY/THERMAL RIBBON IS
NORTH OF CWFA ON FRIDAY. HOWEVER MID LEVEL MOISTURE AND LIFT
GENERATED BY EXIT REGION OF 300MB JET JUSTIFY LOW POPS SAGGING
INTO NORTHERN THIRD CWFA AFTER 00Z SATURDAY. BASED ON CURRENT AND
PREVIOUS GUIDANCE WILL CONTINUE TO SPREAD POPS SOUTH WITH
APPROACHING SHORT WAVE...INCREASING CYCLONIC FLOW AND LIFT IN LEFT
REAR QUAD OF JET.
00Z SUITE OF MODELS IN PRETTY GOOD AGREEMENT WITH THE TIMING OF THE
NEXT COLD SURGE. THE TEMPERATURE WILL PROBABLY PEAK EARLY SATURDAY
THEN BEGIN ANOTHER DOWNWARD SPIRAL BEHIND THE FRONT. SUBSIDENCE
BEHIND THE SHORTWAVE...MODEST PRESSURE RISE/FALL COUPLET...DEEP
LAYERED COLD ADVECTION AND ORIENTATION OF ISOBARS SUGGEST QUITE
BREEZY CONDITIONS POST FRONTAL FOR SATURDAY. HAVE UPPED WIND SPEEDS
ON SATURDAY INTO EVENING USING GFS/BCMOS BLEND.
BEYOND THAT THE LAST FEW DAYS OF 2013 ARE COLD AND DRY AS ARCTIC
RIDGE SLIDES ALONG AND WEST OF CWFA.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z WEDNESDAY MORNING)
ISSUED AT 651 AM CST TUE DEC 24 2013
THE MAIN CONCERN WILL BE SNOWFALL MOVING THROUGH THE REGION TODAY.
THIS REGION OF SNOWFALL WILL BE ASSOCIATED WITH MOSTLY MVFR
CIGS/VSBY...AND POSSIBLY PERIODS OF IFR CONDITIONS.
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...WINTER WEATHER ADVISORY UNTIL 7 PM CST THIS EVENING FOR NDZ039-
053.
WINTER WEATHER ADVISORY UNTIL 1 PM CST THIS AFTERNOON FOR NDZ008-
016-027-029-030.
MN...WINTER WEATHER ADVISORY UNTIL 7 PM CST THIS EVENING FOR MNZ002-
003-005-006-008-009-013>017-022>024-027>032-040.
WINTER WEATHER ADVISORY UNTIL 1 PM CST THIS AFTERNOON FOR MNZ001-
004-007.
&&
$$
UPDATE...TG
SHORT TERM...TG
LONG TERM...EWENS/TG
AVIATION...TG
AREA FORECAST DISCUSSION
NWS CLEVELAND OH
603 PM EST TUE DEC 24 2013
.SYNOPSIS...
HIGH PRESSURE FROM THE CENTRAL LAKES TO THE LOWER OHIO VALLEY WILL
MOVE TO THE MIDDLE ATLANTIC STATES ON CHRISTMAS DAY. A COLD FRONT
WILL MOVE EAST ACROSS THE AREA THURSDAY. HIGH PRESSURE WILL BUILD
OVER THE REGION THURSDAY NIGHT. THE HIGH PRESSURE AREA WILL DRIFT
SOUTH TO THE TENNESSEE VALLEY BY SATURDAY AND ALLOW FOR MODERATING
TEMPERATURES.
&&
.NEAR TERM /UNTIL 6 AM WEDNESDAY MORNING/...
LAKE EFFECT SNOWS ARE WINDING DOWN THIS AFTERNOON AS THE UPPER
TROUGH MOVES EAST THE AREA AND THE INVERSION LOWERS ACROSS THE
REGION. THE FLOW HAS VEERED TO NORTHWEST DECREASING THE FETCH
ACROSS LAKE ERIE. VISIBLE IMAGERY SHOWS CUMULUS CLOUDS GRADUALLY
CLEARING OVER THE WESTERN SECTION OF THE LAKE. LAKE EFFECT BANDS
SHOULD CONTINUE TO DIMINISH. ONE TO TWO MORE INCHES OF SNOW ARE
POSSIBLE THIS EVENING OVER FAR NE OHIO AND NW PA SO WILL CONTINUE
THE LAKE EFFECT HEADLINES WITH NO CHANGES. WILL KEEP LIKELY POPS
IN NW PA FOR THIS EVENING WITH DRY CONDITIONS OVER THE WESTERN 2/3
OF THE FORECAST AREA.
WITH FRESH SNOW COVER EAST OF CLE AND SOME CLEARING EXPECTED ALONG
WITH LIGHT WINDS...SOME RADIATIONAL COOLING IS EXPECTED
ESPECIALLY IN GEAUGA COUNTY. THE HRRR MODEL SURFACE TEMPERATURES
DROP INTO THE SINGLE DIGITS IN THIS AREA AND THIS SEEMS VERY
REASONABLE. ELSEWHERE SLIGHTLY WARMER CONDITIONS ARE EXPECTED
GIVEN SLIGHTLY MORE WIND AND EITHER SLOWER CLEARING THIS EVENING
OR AN INCREASE IN CLOUDS AFTER MIDNIGHT. STILL READING WILL BE
RATHER COLD AND BE AROUND 10.
&&
.SHORT TERM /6 AM WEDNESDAY MORNING THROUGH FRIDAY NIGHT/...
ANOTHER SHORT WAVE WILL MOVE EAST ACROSS THE GREAT LAKES CHRISTMAS
DAY AND PRODUCE MODEST ISENTROPIC LIFT ACROSS THE AREA. THE
AIRMASS IS QUITE DRY SO LITTLE SNOWFALL IS EXPECTED AND WILL BE
MAINLY NEAR LAKE ERIE WITH LITTLE MORE THAN A DUSTING.
TEMPERATURES WILL MODERATE TO THE MID TO UPPER 20S.
ANOTHER IMPULSE WILL DEEPEN THE TROUGH WEDNESDAY EVENING AND EARLY
THURSDAY WITH A COLD FRONTAL PASSAGE TOWARD MORNING. THE LOW LEVEL
FLOW VEERS TO A MORE WESTERLY DIRECTION WITH 850 MB TEMPERATURES
COOLING TO NEAR -12C SO SOME LAKE EFFECT/ENHANCED SNOW IS EXPECTED
IN THE SNOWBELT THURSDAY. THE FLOW WILL BACK TO A SOUTHWESTERLY
DIRECTION THURSDAY NIGHT ALONG WITH WARMING CONDITIONS SO ANY LAKE
EFFECT SNOWBANDS WILL SHIFT OFFSHORE AND DIMINISH.
FAIR MODERATING CONDITIONS ARE EXPECTED FRIDAY AS 850 MB
TEMPERATURES WARM TO NEAR 0C AS A SOUTHWESTERLY FLOW DEVELOPS.
&&
.LONG TERM /SATURDAY THROUGH TUESDAY/...
DRY WEATHER IS EXPECTED ON SATURDAY AS A FRONT APPROACHES FOR
SUNDAY. THE AMOUNT OF MOISTURE ASSOCIATED WITH THE FRONT IS NOT THAT
IMPRESSIVE SO WILL CONTINUE CHANCE POPS ON SUNDAY INTO SUNDAY NIGHT.
PRECIPITATION TYPE IS IN QUESTION. THE ECMWF IS A LITTLE WARMER...SO
WILL MENTION A MIX FOR SUNDAY. FOR SUNDAY NIGHT IT WILL BE COLD
ENOUGH JUST FOR SNOW SHOWERS. SNOW SHOWERS WILL LINGER INTO MONDAY
NIGHT...LOW CHANCE WITH MOISTURE LIMITED EVEN THOUGH THE LAKE AND
850 MB TEMPERATURE DIFFERENCE WILL BE NEAR 20C.
ANOTHER FRONTAL SYSTEM WILL BE MOVING IN ON TUESDAY. SOME TIMING
QUESTIONS WITH THAT...SO WILL LEAVE THE POPS LOW FOR THE TIME BEING.
&&
.AVIATION /00Z WEDNESDAY THROUGH SUNDAY/...
HIGH PRESSURE MOVING OVER THE AREA THRU MIDNIGHT WILL HELP TO END
THE LAKE EFFECT SHSN AROUND ERI WHILE THE MVFR STRATO CU OVER ALL
BUT THE WESTERN AREA WILL RECEDE TO THE EAST. HIGH AND MID LEVEL
CLOUDS WILL SPREAD BACK IN FROM THE WEST LATER TONIGHT THRU MIDDAY
WED. SOME LIGHT SHSN MAY BE SPREADING ACROSS THE AREA AROUND AND
NEAR LERI BY LATE IN THE DAY WED BUT SINCE THE OVERALL POP FOR
ANYTHING MEASURABLE IS ONLY 30% WILL JUST CARRY 6SM SHSN OR VCSH IN
TAFS LATE WED AFTERNOON.
.OUTLOOK...NON VFR POSSIBLE WEDNESDAY NIGHT AND THURSDAY IN SNOW
SHOWERS.
&&
.MARINE...
SMALL CRAFT ADVISORIES WILL BE NEEDED FREQUENTLY INTO EARLY NEXT
WEEK...ESPECIALLY ON THE EAST END OF THE LAKE.
A RIDGE IS BUILDING IN TONIGHT...SO THE WINDS AND WAVES WILL
CONTINUE TO DECREASE. WILL LET THE SMALL CRAFT ADVISORY EXPIRE AT 9
PM ON THE EAST END...IT WILL BE CLOSE.
THE NEXT THREAT FOR A SMALL CRAFT ADVISORY WILL BE LATE WEDNESDAY
NIGHT INTO THURSDAY AFTER ANOTHER FRONT MOVES THROUGH. ANOTHER FRONT
MOVES THROUGH LATE FRIDAY AND SATURDAY NIGHT INTO SUNDAY. THIS FRONT
WILL PROMPT THE NEED FOR A SMALL CRAFT ADVISORY THAT MAY LAST INTO
EARLY NEXT WEEK AS THE WEST TO NORTHWEST FLOW WILL BE PERSISTENT.
&&
.CLE WATCHES/WARNINGS/ADVISORIES...
OH...LAKE EFFECT SNOW ADVISORY UNTIL 10 PM EST THIS EVENING FOR
OHZ014-089.
PA...LAKE EFFECT SNOW ADVISORY UNTIL 10 PM EST THIS EVENING FOR
PAZ003.
LAKE EFFECT SNOW WARNING UNTIL 10 PM EST THIS EVENING FOR
PAZ001-002.
MARINE...SMALL CRAFT ADVISORY UNTIL 9 PM EST THIS EVENING FOR
LEZ146>149.
&&
$$
SYNOPSIS...LAPLANTE
NEAR TERM...LAPLANTE
SHORT TERM...LAPLANTE
LONG TERM...KIELTYKA
AVIATION...ADAMS
MARINE...KIELTYKA
AREA FORECAST DISCUSSION
NWS CLEVELAND OH
357 PM EST TUE DEC 24 2013
.SYNOPSIS...
HIGH PRESSURE FROM THE CENTRAL LAKES TO THE LOWER OHIO VALLEY WILL
MOVE TO THE MIDDLE ATLANTIC STATES ON CHRISTMAS DAY. A COLD FRONT
WILL MOVE EAST ACROSS THE AREA THURSDAY. HIGH PRESSURE WILL BUILD
OVER THE REGION THURSDAY NIGHT. THE HIGH PRESSURE AREA WILL DRIFT
SOUTH TO THE TENNESSEE VALLEY BY SATURDAY AND ALLOW FOR MODERATING
TEMPERATURES.
&&
.NEAR TERM /UNTIL 6 AM WEDNESDAY MORNING/...
LAKE EFFECT SNOWS ARE WINDING DOWN THIS AFTERNOON AS THE UPPER
TROUGH MOVES EAST THE AREA AND THE INVERSION LOWERS ACROSS THE
REGION. THE FLOW HAS VEERED TO NORTHWEST DECREASING THE FETCH
ACROSS LAKE ERIE. VISIBLE IMAGERY SHOWS CUMULUS CLOUDS GRADUALLY
CLEARING OVER THE WESTERN SECTION OF THE LAKE. LAKE EFFECT BANDS
SHOULD CONTINUE TO DIMINISH. ONE TO TWO MORE INCHES OF SNOW ARE
POSSIBLE THIS EVENING OVER FAR NE OHIO AND NW PA SO WILL CONTINUE
THE LAKE EFFECT HEADLINES WITH NO CHANGES. WILL KEEP LIKELY POPS
IN NW PA FOR THIS EVENING WITH DRY CONDITIONS OVER THE WESTERN 2/3
OF THE FORECAST AREA.
WITH FRESH SNOW COVER EAST OF CLE AND SOME CLEARING EXPECTED ALONG
WITH LIGHT WINDS...SOME RADIATIONAL COOLING IS EXPECTED
ESPECIALLY IN GEAUGA COUNTY. THE HRRR MODEL SURFACE TEMPERATURES
DROP INTO THE SINGLE DIGITS IN THIS AREA AND THIS SEEMS VERY
REASONABLE. ELSEWHERE SLIGHTLY WARMER CONDITIONS ARE EXPECTED
GIVEN SLIGHTLY MORE WIND AND EITHER SLOWER CLEARING THIS EVENING
OR AN INCREASE IN CLOUDS AFTER MIDNIGHT. STILL READING WILL BE
RATHER COLD AND BE AROUND 10.
&&
.SHORT TERM /6 AM WEDNESDAY MORNING THROUGH FRIDAY NIGHT/...
ANOTHER SHORT WAVE WILL MOVE EAST ACROSS THE GREAT LAKES CHRISTMAS
DAY AND PRODUCE MODEST ISENTROPIC LIFT ACROSS THE AREA. THE
AIRMASS IS QUITE DRY SO LITTLE SNOWFALL IS EXPECTED AND WILL BE
MAINLY NEAR LAKE ERIE WITH LITTLE MORE THAN A DUSTING.
TEMPERATURES WILL MODERATE TO THE MID TO UPPER 20S.
ANOTHER IMPLUSE WILL DEEPEN THE TROUGH WEDNESDAY EVENING AND EARLY
THURSDAY WITH A COLD FRONTAL PASSAGE TOWARD MORNING. THE LOW LEVEL
FLOW VEERS TO A MORE WESTERLY DIRECTION WITH 850 MB TEMPERATURES
COOLING TO NEAR -12C SO SOME LAKE EFFECT/ENHANCED SNOW IS EXPECTED
IN THE SNOWBELT THURSDAY. THE FLOW WILL BACK TO A SOUTHWESTERLY
DIRECTION THURSDAY NIGHT ALONG WITH WARMING CONDITIONS SO ANY LAKE
EFFECT SNOWBANDS WILL SHIFT OFFSHORE AND DIMINISH.
FAIR MODERATING CONDITIONS ARE EXPECTED FRIDAY AS 850 MB
TEMPERATURES WARM TO NEAR 0C AS A SOUTHWESTERLY FLOW DEVELOPS.
&&
.LONG TERM /SATURDAY THROUGH TUESDAY/...
DRY WEATHER IS EXPECTED ON SATURDAY AS A FRONT APPROACHES FOR
SUNDAY. THE AMOUNT OF MOISTURE ASSOCIATED WITH THE FRONT IS NOT THAT
IMPRESSIVE SO WILL CONTINUE CHANCE POPS ON SUNDAY INTO SUNDAY NIGHT.
PRECIPITATION TYPE IS IN QUESTION. THE ECMWF IS A LITTLE WARMER...SO
WILL MENTION A MIX FOR SUNDAY. FOR SUNDAY NIGHT IT WILL BE COLD
ENOUGH JUST FOR SNOW SHOWERS. SNOW SHOWERS WILL LINGER INTO MONDAY
NIGHT...LOW CHANCE WITH MOISTURE LIMITED EVEN THOUGH THE LAKE AND
850 MB TEMPERATURE DIFFERENCE WILL BE NEAR 20C.
ANOTHER FRONTAL SYSTEM WILL BE MOVING IN ON TUESDAY. SOME TIMING
QUESTIONS WITH THAT...SO WILL LEAVE THE POPS LOW FOR THE TIME BEING.
&&
.AVIATION /18Z TUESDAY THROUGH SUNDAY/...
THE FIRST BATCH OF SYNOPTIC SNOW IS MOVING EAST BUT THE TROUGH
OVER LAKE ERIE WILL DROP SOUTHEAST ACROSS NE OH/NW PA AND EXPECT
ADDITIONAL LAKE ENHANCED SNOW SHOWERS TO CONTINUE THROUGH LATE
MORNING OR EARLY AFTERNOON WITH MVFR CEILINGS AND OCCASIONAL IFR
VISIBILITIES IN THE HEAVIER SNOW SHOWERS. THE SNOW SHOWERS COULD
LAST INTO THE EVENING AT KERI IF LAKE HURON SNOW BANDS CAN GET
INTO NW PA. THE AIR MASS WILL REALLY DRY OUT TODAY AS ARCTIC AIR
OVERSPREADS THE AREA. EXPECT CEILINGS TO IMPROVE TO VFR FROM WEST
TO EAST WITH CLEARING TONIGHT AS THE RIDGE AXIS PASSES TO THE
EAST. MID AND HIGH CLOUDS WILL SPREAD IN LATER TONIGHT.
.OUTLOOK...NON VFR POSSIBLE WEDNESDAY NIGHT AND THURSDAY IN SNOW
SHOWERS.
&&
.MARINE...
SMALL CRAFT ADVISORIES WILL BE NEEDED FREQUENTLY INTO EARLY NEXT
WEEK...ESPECIALLY ON THE EAST END OF THE LAKE.
A RIDGE IS BUILDING IN TONIGHT...SO THE WINDS AND WAVES WILL
CONTINUE TO DECREASE. WILL LET THE SMALL CRAFT ADVISORY EXPIRE AT 9
PM ON THE EAST END...IT WILL BE CLOSE.
THE NEXT THREAT FOR A SMALL CRAFT ADVISORY WILL BE LATE WEDNESDAY
NIGHT INTO THURSDAY AFTER ANOTHER FRONT MOVES THROUGH. ANOTHER FRONT
MOVES THROUGH LATE FRIDAY AND SATURDAY NIGHT INTO SUNDAY. THIS FRONT
WILL PROMPT THE NEED FOR A SMALL CRAFT ADVISORY THAT MAY LAST INTO
EARLY NEXT WEEK AS THE WEST TO NORTHWEST FLOW WILL BE PERSISTENT.
&&
.CLE WATCHES/WARNINGS/ADVISORIES...
OH...LAKE EFFECT SNOW ADVISORY UNTIL 10 PM EST THIS EVENING FOR
OHZ014-089.
PA...LAKE EFFECT SNOW ADVISORY UNTIL 10 PM EST THIS EVENING FOR
PAZ003.
LAKE EFFECT SNOW WARNING UNTIL 10 PM EST THIS EVENING FOR
PAZ001-002.
MARINE...SMALL CRAFT ADVISORY UNTIL 9 PM EST THIS EVENING FOR
LEZ146>149.
&&
$$
SYNOPSIS...LAPLANTE
NEAR TERM...LAPLANTE
SHORT TERM...LAPLANTE
LONG TERM...KIELTYKA
AVIATION...KIELTYKA
MARINE...KIELTYKA
AREA FORECAST DISCUSSION
NWS TULSA OK
1102 PM CST MON DEC 23 2013
.AVIATION...
CONCERNING TAF SITES KTUL/KRVS/KBVO/KMLC/KXNA/KFYV/KFSM.
FORECAST SITES CURRENTLY RESIDE BETWEEN TWO REGION OF LOWER
CEILINGS BOTH TO THE EAST AND WEST. THE EASTERN LOW CLOUDS MAY
BRUSH FAR NW AR WITHIN THE NEXT FEW HOURS...HOWEVER THE TREND WILL
BE TOWARD FEWER CLOUDS ACROSS THIS REGION. FURTHER WEST...MVFR
CEILINGS ARE LIKELY TO REMAIN VERY NEAR THE HIGHWAY 75 CORRIDOR
INCREASING THE UNCERTAINTY FOR IMPACTS OK SITES. THIS REGION OF
LOWER CLOUDS SHOULD ERODE AFTER SUNRISE WITH VFR CONDITIONS
EVENTUALLY PREVAILING.
&&
.PREV DISCUSSION... /ISSUED 911 PM CST MON DEC 23 2013/
..UPDATE...
DISCUSSION...
UPDATED THE FORECAST EARLIER IN THE EVENING TO REMOVE POPS. THE
MAIN VARIABLE FOR THE REMAINDER OF THE NIGHT IS THE EXTENT OF LOW
CLOUDS AND THE EFFECT ON MINIMUM TEMPERATURES. THE RUC KEEPS
PLENTY OF MOISTURE/CLOUDS OVERNIGHT... ALTHOUGH CURRENT SATELLITE
IMAGES SHOW PARTIAL CLEARING ACROSS THE AREA. WAS TEMPTED TO
RAISE MINIMUM TEMPERATURES A FEW DEGREES BASED ON ANTICIPATED
CLOUDS. HOWEVER... WITH AREAS OF CLEAR SKIES OUT THERE
CURRENTLY... HAVE ENOUGH DOUBT THAT RADIATIONAL COOLING WILL BE
INHIBITED ALL THAT MUCH. THE BOTTOM LINE IS THAT FORECAST MINIMUM
TEMPERATURES HAVE BEEN LEFT UNCHANGED. THEREFORE... WILL UPDATE
PRODUCTS AT THIS TIME.
&&
.PRELIMINARY POINT TEMPS/POPS...
TUL 14 40 26 46 / 0 0 10 10
FSM 20 44 26 49 / 10 0 0 10
MLC 17 46 28 49 / 0 0 0 10
BVO 9 40 23 46 / 0 0 10 10
FYV 12 38 24 46 / 10 0 10 10
BYV 11 36 27 46 / 10 0 10 10
MKO 15 43 25 47 / 0 0 0 10
MIO 10 40 25 46 / 10 0 10 10
F10 16 44 27 47 / 0 0 0 10
HHW 21 46 27 50 / 0 0 0 10
&&
.TSA WATCHES/WARNINGS/ADVISORIES...
OK...NONE.
AR...NONE.
&&
$$
AVIATION...07
AREA FORECAST DISCUSSION...UPDATED
NWS ABERDEEN SD
1140 AM CST TUE DEC 24 2013
.UPDATE...
SEE THE UPDATED AVIATION DISCUSSION BELOW.
HAD SEVERAL REPORTS OF FREEZING RAIN/SLEET ACROSS THE WEST THIS
MORNING WITH SNOW MOVING EAST. THE BAND OF ECHOES IS NOT THAT WIDE
THIS MORNING AS IT WAS MOVING EAST. THE HRRR MODEL SHOWED THIS
BAND WELL. THUS...IT LOOKS LIKE THE PRECIPITATION WILL END EARLY
THIS AFTERNOON AND MAY CANCEL ADVISORY EARLY OUT WEST. THE EAST
MAY YET HAVE BETTER DEVELOPMENT THIS AFTERNOON WITH THE SNOWFALL.
THE LATEST NAM AND GFS SHOW MORE DEVELOPMENT AND QPF THROUGH 00Z
THIS EVENING ACROSS THE EASTERN CWA.
&&
.PREVIOUS DISCUSSION...
.SHORT TERM...TODAY AND TONIGHT
PRIMARY FORECAST CHALLENGES ARE P-TYPE AND SNOW AMOUNTS THROUGH
THIS EVENING. FORECASTER CONFIDENCE: LOW TO MEDIUM
VERY CHALLENGING FORECAST SHAPING UP OVER THE AREA...WITH PLENTY
OF ISSUES. 00Z UPPER AIR ANALYSIS AND WATER VAPOR ANALYSIS
INDICATED A VERY POTENT UPPER SHORTWAVE/PV ANOMALY SLIDING E/SEWD
ACROSS THE NRN ROCKIES. VERY IMPRESSIVE H5 HEIGHT FALLS ON THE
ORDER OF 150 METERS NOTED OVER THE PAC NW. IN CONJUNCTION...VERY
STRONG LOW LEVEL WAA SIGNAL NOTED ON REGIONAL RAOBS...WITH A
SIGNIFICANT INCREASE IN PWATS. AT THE SFC...MSAS ANALYSIS AT 10Z
SHOWED A DEEPENING SFC LOW OVER MT/WY WITH A STRONG SLY SFC FLOW
OVER THE CWA.
INITIAL CONCERN IS WIND CHILL VALUES. WITH ABOVE MENTIONED WAA
PATTERN...TEMPS HAVE BEEN STEADILY RISING OVERNIGHT WITH READINGS
IN THE CWA NOW IN THE SINGLE DIGITS ABOVE AND BELOW ZERO. STILL
FLIRTING WITH WIND CHILL ADV CRITERIA /ESP IN THE FAR EAST/...BUT
BELIEVE WE WILL BE ABLE TO CANCEL AS SCHEDULED AROUND 12Z /6AM
CST/.
ATTENTION THEN TURNS TO THE P-TYPE AND SNOW AMOUNTS WITH THE NEXT
UPPER DISTURBANCE. RADAR ECHOES ARE ALREADY EXPANDING ACROSS
PORTIONS OF MT AND WRN SD AS OF 10Z AND THIS LINE OF PCPN IS
MOVING EWD. FORECAST SOUNDINGS INDICATE A WELL DEFINED WARM LAYER
TO IMPACT AT LEAST THE WRN CWA...SO EXPECTING AN WINTRY MIX OF
FREEZING RAIN...SLEET...AND SNOW THROUGH MID-MORNING. ICE ACCUMS
STILL EXPECTED TO BE LIGHT...GENERALLY LESS THAN A TENTH OF AN
INCH. HIGHEST ICE AMOUNTS ARE CURRENTLY FORECAST ALONG AND WEST OF
THE MISSOURI RIVER NEAR KPIR. WILL BE INTERESTING TO SEE HOW LONG
ANY ICING CAN PERSIST...AS THE MODELS DO INDICATE QUITE A BIT OF
DRY AIR WHICH MAY ACT TO WET BULB THE COLUMN BELOW FREEZING
RELATIVELY QUICKLY. FURTHER EAST...EXPECTING SNOW TO BE THE
DOMINANT PTYPE AS THE WARM NOSE FOLDS S/SE. BIG QUESTIONS STILL
REMAIN ON STRENGTH AND LONGEVITY OF FORCING. 00Z GFS WAS THE MOST
BULLISH WITH QPF IN OUR AREA...WITH 00Z NAM/GEM SHOWING BEST
FORCING/SATURATION OVER ND. DURING THIS FORECAST CYCLE...USED A
MODEL BLEND OF GFS/ECMWF WHICH APPEARED MOST REASONABLE. IT SHOULD
BE NOTED THAT A NUMBER OF THE HI-RES MODELS REMAIN VERY PROGRESSIVE
WITH THE MOVEMENT OF THIS FRONTAL BAND. THIS WOULD SUGGEST A
RATHER SHORT LIVED...BUT INTENSE BURST OF SNOWFALL. ALL IN
ALL...HAVE SNOW AMOUNTS IN THE EAST RANGING FROM AROUND 4 INCHES
IN OUR MN COUNTIES TO AROUND 2 INCHES WEST OF ABERDEEN. ONCE THE
EVOLUTION OF THIS SYSTEM BECOMES CLEARER...THE AXIS OF HEAVIEST
QPF MAY NEED TO BE ADJUSTED. WINTER WX ADVISORY WILL RUN TO 00Z
WED. TEMPERATURES TODAY WILL BE MUCH MILDER...WITH READINGS
GENERALLY IN THE TEENS TO LOW 30S.
COULD SEE SOME LINGERING SNOW IN THE FAR EAST THIS
EVENING...BEFORE YET ANOTHER SHORTWAVE DROPS SWD LATE TONIGHT.
WILL SEE ANOTHER CHANCE FOR LIGHT SNOW WITH THIS LOBE OF
ENERGY...AND SOME POTENTIAL FOR WINDS IN THE WAKE OF THE SYSTEM.
.LONG TERM...WEDNESDAY THROUGH MONDAY
TRACKING S/W ENERGY OVER ALBERTA/SASKATCHEWAN EMBEDDED WITHIN THE
LONGWAVE TROF...SAID S/W ENERGY SHOULD BE SWEEPING SEWD THROUGH
THE FAR NORTHEASTERN CWA ON WEDNESDAY...POTENTIALLY DRAGGING SOME
LIGHT SNOW UP OVER THE PRAIRIE COTEAU. LOW LEVEL CAA ON WEDNESDAY
AND SOME SUBSIDENCE PROMOTING STEEP LOW LEVEL LAPSE RATES/BETTER
MIXING ENVIRONMENT AND A BETTER POTENTIAL FOR HAZARDOUS BLOWING
SNOW CONCERNS COMING LESS THAN 24 HOURS AFTER AN EXPECTED LIGHT
SNOW EVENT. MAY NEED TO CONSIDER A WINT WX ADV FOR BLOWING SNOW.
OTHERWISE...STILL MONITORING NORTHWEST FLOW THROUGHOUT THE
REMAINDER OF THE FORECAST. STILL LOOKS LIKE THE CAA
WEDNESDAY/WEDNESDAY NIGHT WILL BE QUICKLY REPLACED BY WARMER
PACIFIC-MODIFIED AIRMASS FROM THURSDAY THROUGH SATURDAY MORNING
BEFORE THE NEXT NW FLOW SYSTEM PUSHES THE POLAR FRONT BACK
SOUTHWARD ACROSS THE REGION DURING THE DAY SATURDAY...WITH ANOTHER
MULTIPLE-DAY PERIOD OF ARCTIC COLD AIR AROUND HEADING INTO NEXT
WEEK.
THE 00Z GFS/ECMWF SOLUTIONS WERE PINGING SATURDAY/SATURDAY NIGHT
AS A POTENTIAL PERIOD OF RATHER STRONG NORTHWEST WINDS.
HOWEVER...WILL PROLLY NEED TO TAKE A WAIT-AND-SEE APPROACH TO HOW
MUCH OF THE REGION WARMS TO ABOVE FREEZING THURSDAY AND FRIDAY FOR
THE POTENTIAL TO PLACE A GOOD CRUST ON TOP OF REGION-WIDE SNOW
COVER...AND THEREFORE JUST HOW MUCH OF THE REGION COULD SEE
SIGNIFICANT BLOWING SNOW PROBLEMS THAT DAY. FOR NOW...JUST ADDED
SOME AREAS OF BLOWING SNOW MENTION INTO THE WEATHER GRIDS FOR
SATURDAY.
&&
.AVIATION...
18Z TAFS FOR THE KABR...KATY...KPIR AND KMBG TERMINALS
PRECIPITATION HAS ENDED AT THE KMBG AND KPIR TAF SITES THIS
MORNING AS THE BAND OF PRECIPITATION CONTINUES TO TRACK EAST INTO
NORTHEAST SOUTH DAKOTA AND WEST CENTRAL MINNESOTA. MVFR CIGS ARE
STILL EXPECTED FOR THE NEXT FEW HOURS AT KPIR AND KMBG HOWEVER.
RECENT REPORTS INDICATE PTYPE HAS TURNED ALL TO SNOW...AND
EXPECTING PRECIP TO REMAIN SNOW AS THE BAND PUSHES EAST OF THE
AREA. MVFR TO IFR CIGS AND VSBYS AT KATY AND KABR WILL GRADUALLY
IMPROVE. WINDS AT KABR AND KATY WILL ALSO SWITCH FROM THE
SOUTHWEST AROUND TO THE NORTHWEST.
&&
.ABR WATCHES/WARNINGS/ADVISORIES...
SD...WINTER WEATHER ADVISORY UNTIL 6 PM CST /5 PM MST/ THIS EVENING
FOR BROWN-BUFFALO-CAMPBELL-CLARK-CODINGTON-CORSON-DAY-DEUEL-
DEWEY-EDMUNDS-FAULK-GRANT-HAMLIN-HAND-HUGHES-HYDE-JONES-
LYMAN-MARSHALL-MCPHERSON-POTTER-ROBERTS-SPINK-STANLEY-SULLY-
WALWORTH.
MN...WINTER WEATHER ADVISORY UNTIL 6 PM CST THIS EVENING FOR BIG
STONE-TRAVERSE.
&&
$$
UPDATE...MOHR
SHORT TERM...FOWLE
LONG TERM...DORN
AVIATION...SERR
WEATHER.GOV/ABERDEEN
AREA FORECAST DISCUSSION...UPDATED
NWS ABERDEEN SD
1055 AM CST TUE DEC 24 2013
.UPDATE...
HAD SEVERAL REPORTS OF FREEZING RAIN/SLEET ACROSS THE WEST THIS
MORNING WITH SNOW MOVING EAST. THE BAND OF ECHOES IS NOT THAT WIDE
THIS MORNING AS IT WAS MOVING EAST. THE HRRR MODEL SHOWED THIS
BAND WELL. THUS...IT LOOKS LIKE THE PRECIPITATION WILL END EARLY
THIS AFTERNOON AND MAY CANCEL ADVISORY EARLY OUT WEST. THE EAST
MAY YET HAVE BETTER DEVELOPMENT THIS AFTERNOON WITH THE SNOWFALL.
THE LATEST NAM AND GFS SHOW MORE DEVELOPMENT AND QPF THROUGH 00Z
THIS EVENING ACROSS THE EASTERN CWA.
&&
.PREVIOUS DISCUSSION...
.SHORT TERM...TODAY AND TONIGHT
PRIMARY FORECAST CHALLENGES ARE P-TYPE AND SNOW AMOUNTS THROUGH
THIS EVENING. FORECASTER CONFIDENCE: LOW TO MEDIUM
VERY CHALLENGING FORECAST SHAPING UP OVER THE AREA...WITH PLENTY
OF ISSUES. 00Z UPPER AIR ANALYSIS AND WATER VAPOR ANALYSIS
INDICATED A VERY POTENT UPPER SHORTWAVE/PV ANOMALY SLIDING E/SEWD
ACROSS THE NRN ROCKIES. VERY IMPRESSIVE H5 HEIGHT FALLS ON THE
ORDER OF 150 METERS NOTED OVER THE PAC NW. IN CONJUNCTION...VERY
STRONG LOW LEVEL WAA SIGNAL NOTED ON REGIONAL RAOBS...WITH A
SIGNIFICANT INCREASE IN PWATS. AT THE SFC...MSAS ANALYSIS AT 10Z
SHOWED A DEEPENING SFC LOW OVER MT/WY WITH A STRONG SLY SFC FLOW
OVER THE CWA.
INITIAL CONCERN IS WIND CHILL VALUES. WITH ABOVE MENTIONED WAA
PATTERN...TEMPS HAVE BEEN STEADILY RISING OVERNIGHT WITH READINGS
IN THE CWA NOW IN THE SINGLE DIGITS ABOVE AND BELOW ZERO. STILL
FLIRTING WITH WIND CHILL ADV CRITERIA /ESP IN THE FAR EAST/...BUT
BELIEVE WE WILL BE ABLE TO CANCEL AS SCHEDULED AROUND 12Z /6AM
CST/.
ATTENTION THEN TURNS TO THE P-TYPE AND SNOW AMOUNTS WITH THE NEXT
UPPER DISTURBANCE. RADAR ECHOES ARE ALREADY EXPANDING ACROSS
PORTIONS OF MT AND WRN SD AS OF 10Z AND THIS LINE OF PCPN IS
MOVING EWD. FORECAST SOUNDINGS INDICATE A WELL DEFINED WARM LAYER
TO IMPACT AT LEAST THE WRN CWA...SO EXPECTING AN WINTRY MIX OF
FREEZING RAIN...SLEET...AND SNOW THROUGH MID-MORNING. ICE ACCUMS
STILL EXPECTED TO BE LIGHT...GENERALLY LESS THAN A TENTH OF AN
INCH. HIGHEST ICE AMOUNTS ARE CURRENTLY FORECAST ALONG AND WEST OF
THE MISSOURI RIVER NEAR KPIR. WILL BE INTERESTING TO SEE HOW LONG
ANY ICING CAN PERSIST...AS THE MODELS DO INDICATE QUITE A BIT OF
DRY AIR WHICH MAY ACT TO WET BULB THE COLUMN BELOW FREEZING
RELATIVELY QUICKLY. FURTHER EAST...EXPECTING SNOW TO BE THE
DOMINANT PTYPE AS THE WARM NOSE FOLDS S/SE. BIG QUESTIONS STILL
REMAIN ON STRENGTH AND LONGEVITY OF FORCING. 00Z GFS WAS THE MOST
BULLISH WITH QPF IN OUR AREA...WITH 00Z NAM/GEM SHOWING BEST
FORCING/SATURATION OVER ND. DURING THIS FORECAST CYCLE...USED A
MODEL BLEND OF GFS/ECMWF WHICH APPEARED MOST REASONABLE. IT SHOULD
BE NOTED THAT A NUMBER OF THE HI-RES MODELS REMAIN VERY PROGRESSIVE
WITH THE MOVEMENT OF THIS FRONTAL BAND. THIS WOULD SUGGEST A
RATHER SHORT LIVED...BUT INTENSE BURST OF SNOWFALL. ALL IN
ALL...HAVE SNOW AMOUNTS IN THE EAST RANGING FROM AROUND 4 INCHES
IN OUR MN COUNTIES TO AROUND 2 INCHES WEST OF ABERDEEN. ONCE THE
EVOLUTION OF THIS SYSTEM BECOMES CLEARER...THE AXIS OF HEAVIEST
QPF MAY NEED TO BE ADJUSTED. WINTER WX ADVISORY WILL RUN TO 00Z
WED. TEMPERATURES TODAY WILL BE MUCH MILDER...WITH READINGS
GENERALLY IN THE TEENS TO LOW 30S.
COULD SEE SOME LINGERING SNOW IN THE FAR EAST THIS
EVENING...BEFORE YET ANOTHER SHORTWAVE DROPS SWD LATE TONIGHT.
WILL SEE ANOTHER CHANCE FOR LIGHT SNOW WITH THIS LOBE OF
ENERGY...AND SOME POTENTIAL FOR WINDS IN THE WAKE OF THE SYSTEM.
.LONG TERM...WEDNESDAY THROUGH MONDAY
TRACKING S/W ENERGY OVER ALBERTA/SASKATCHEWAN EMBEDDED WITHIN THE
LONGWAVE TROF...SAID S/W ENERGY SHOULD BE SWEEPING SEWD THROUGH
THE FAR NORTHEASTERN CWA ON WEDNESDAY...POTENTIALLY DRAGGING SOME
LIGHT SNOW UP OVER THE PRAIRIE COTEAU. LOW LEVEL CAA ON WEDNESDAY
AND SOME SUBSIDENCE PROMOTING STEEP LOW LEVEL LAPSE RATES/BETTER
MIXING ENVIRONMENT AND A BETTER POTENTIAL FOR HAZARDOUS BLOWING
SNOW CONCERNS COMING LESS THAN 24 HOURS AFTER AN EXPECTED LIGHT
SNOW EVENT. MAY NEED TO CONSIDER A WINT WX ADV FOR BLOWING SNOW.
OTHERWISE...STILL MONITORING NORTHWEST FLOW THROUGHOUT THE
REMAINDER OF THE FORECAST. STILL LOOKS LIKE THE CAA
WEDNESDAY/WEDNESDAY NIGHT WILL BE QUICKLY REPLACED BY WARMER
PACIFIC-MODIFIED AIRMASS FROM THURSDAY THROUGH SATURDAY MORNING
BEFORE THE NEXT NW FLOW SYSTEM PUSHES THE POLAR FRONT BACK
SOUTHWARD ACROSS THE REGION DURING THE DAY SATURDAY...WITH ANOTHER
MULTIPLE-DAY PERIOD OF ARCTIC COLD AIR AROUND HEADING INTO NEXT
WEEK.
THE 00Z GFS/ECMWF SOLUTIONS WERE PINGING SATURDAY/SATURDAY NIGHT
AS A POTENTIAL PERIOD OF RATHER STRONG NORTHWEST WINDS.
HOWEVER...WILL PROLLY NEED TO TAKE A WAIT-AND-SEE APPROACH TO HOW
MUCH OF THE REGION WARMS TO ABOVE FREEZING THURSDAY AND FRIDAY FOR
THE POTENTIAL TO PLACE A GOOD CRUST ON TOP OF REGION-WIDE SNOW
COVER...AND THEREFORE JUST HOW MUCH OF THE REGION COULD SEE
SIGNIFICANT BLOWING SNOW PROBLEMS THAT DAY. FOR NOW...JUST ADDED
SOME AREAS OF BLOWING SNOW MENTION INTO THE WEATHER GRIDS FOR
SATURDAY.
&&
.AVIATION...
12Z TAFS FOR THE KABR...KATY...KPIR AND KMBG TERMINALS
VFR CONDITIONS ARE BEGINNING TO DETERIORATE ACROSS THE REGION. SO
FAR...KMBG HAS DROPPED TO AN IFR CIG CONDITION WHILE KABR...KATY
AND KPIR HAVE SEEN AN INCREASE IN MID/HIGH CLOUDINESS OVER THE
PAST 6 TO 12 HOURS. REGIONAL RADAR DISPLAYS SHOW PRECIPITATION
APPROACHING THE KMBG AND KPIR TERMINALS RIGHT NOW...AND LOW LEVEL
TEMPERATURE PROGS ARE ALL STILL VERY SUPPORTIVE OF MIXED PRECIP
AND FREEZING PRECIP THIS MORNING FOR A FEW HOURS AT BOTH
TERMINALS. AS SUCH...FREEZING RAIN AND ICE PELLETS/SLEET HAVE BEEN
INCORPORATED INTO THE KPIR AND KMBG TAFS FOR A COUPLE HOURS THIS
MORNING.
FURTHER EAST...THE KABR AND KATY TERMINALS WILL SEE SUB-VFR
CIG/VIS CONDITIONS IN SNOW SETTING UP AT OR AFTER 15Z THIS
MORNING...PERSISTING WELL INTO THE AFTERNOON AND PERHAPS EARLY
EVENING HOURS. CONDITIONS SHOULD BEGIN IMPROVING AT ALL FOUR
TERMINALS FROM NORTHWEST TO SOUTHEAST FROM LATE THIS AFTERNOON
THROUGH LATE THIS EVENING.
&&
.ABR WATCHES/WARNINGS/ADVISORIES...
SD...WINTER WEATHER ADVISORY UNTIL 6 PM CST /5 PM MST/ THIS EVENING
FOR BROWN-BUFFALO-CAMPBELL-CLARK-CODINGTON-CORSON-DAY-DEUEL-
DEWEY-EDMUNDS-FAULK-GRANT-HAMLIN-HAND-HUGHES-HYDE-JONES-
LYMAN-MARSHALL-MCPHERSON-POTTER-ROBERTS-SPINK-STANLEY-SULLY-
WALWORTH.
MN...WINTER WEATHER ADVISORY UNTIL 6 PM CST THIS EVENING FOR BIG
STONE-TRAVERSE.
&&
$$
UPDATE...MOHR
SHORT TERM...FOWLE
LONG TERM...DORN
AVIATION...DORN
WEATHER.GOV/ABERDEEN
FOR FREQUENTLY ASKED QUESTIONS ABOUT THE AREA FORECAST DISCUSSION
VISIT...
HTTP://WEATHER.GOV/SALTLAKECITY/GENERAL/AFD_FAQS.PHP (ALL LOWER CASE)
AREA FORECAST DISCUSSION
NWS TAUNTON MA
322 AM EST THU DEC 26 2013
.SYNOPSIS...
A WEAK AND QUICK DISTURBANCE WILL BRING A MIX OF RAIN AND SNOW FOR
THE REGION TODAY. WHILE COOL FOR FRIDAY...MILDER CONDITIONS MOVE
IN FOR THE WEEKEND. LOW PRESSURE WILL MOVE NORTHEAST FROM THE
GULF OF MEXICO WILL PASS NEAR NANTUCKET SUNDAY NIGHT...THEN MOVE
SOUTH OF NOVA SCOTIA MONDAY MORNING. FRIGID AIR WILL INVADE THE
REGION BY TUESDAY.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
STRONGER NORTHERN STREAM IMPULSE THROUGH THE BROADER TROUGH REGIME
INVOKES A WEAK AREA OF LOW PRES SOUTH AND OFFSHORE OF NEW ENGLAND
WITHIN THE BETTER BAROCLINIC ZONE BY MIDDAY...QUICKLY MOVING
NORTHEASTWARD AND AMPLIFYING ACROSS THE GULF OF MAINE BY EVENING.
DURING THIS AMPLIFICATION...ATTENDANT DYNAMICS AND JET STREAK
ENHANCE SOUTH-SOUTHWESTERLY LOW- TO MID-LEVEL FLOW RESULTING IN
LOCALIZED MOISTURE CONVERGENCE ALONG THE LEADING WARM-FRONT /N-NE
QUADRANT OF THE SURFACE LOW/ WHERE FRONTOGENESIS/ISENTROPIC FORCING
IS MAXIMIZED.
ALREADY THIS MORNING...RADAR ECHOES ARE BUILDING ACROSS UPSTATE NY
OUT AHEAD OF THE NORTHERN STREAM IMPULSE...WHILE PER SATELLITE
TRENDS...LOW CLOUDS AND MOISTURE ARE BEING DRAWN UP FROM THE SOUTH.
SO WITH CERTAINTY...THE HEAVIEST OF PRECIP IMPACTS E/SE PORTIONS OF
SOUTHERN NEW ENGLAND WITH ONE TO TWO TENTHS /THE GREATEST OF WHICH
WILL BE ACROSS THE EASTERN CAPE AND NANTUCKET/. LESSER AMOUNTS
EXPECTED FOR THE NORTH AND WEST INTERIOR. CLOUDS ON THE INCREASE
SOUTH AND WEST PRESENTLY WILL BEGIN TO CLEAR OUT LATE.
BUT SOME QUESTION AS TO HOW QUICKLY ARCTIC AIR WILL SCOUR OUT. NOT A
ROBUST SYSTEM AND ONSHORE SOUTHERLY FLOW WILL BE LIGHT. WHILE MILDER
AIR WILL WORK IN SOUTH TO NORTH...CONSIDERING HOW LONG WE HAVE BEEN
IN AN ARCTIC GRIP...FEEL THE PROGRESSION OF MILDER AIR WILL BE SLOW
AGAINST THE ARCTIC AIRMASS. SUSPECT COASTAL LOCATIONS AND ADJACENT
PLAINS WILL WARM ABOVE FREEZING...WHILE INTERIOR LOCALES /ESPECIALLY
THOSE WITH A REMAINING SNOWPACK/ WILL STAY AT OR BELOW FREEZING
THROUGHOUT THE EVENT. WHILE THE HRRR MAY BE TOO COLD...THE WRF-ARW
2M TEMPS ARE A GOOD APPROXIMATION AS TO THINKING.
IN THE END...SNOW IS EXPECTED INITIALLY MIXING OVER TO RAIN FOR
COASTAL COMMUNITIES AND ADJACENT PLAINS...WITH MAINLY ALL SNOW FOR
THE NORTHERN AND WESTERN INTERIOR /NORTH AND WEST OF I-84 TO I-90 TO
I-95 AS AN APPROXIMATION/. ROUGHLY 1 TO 2 INCHES FOR THE HIGHER
TERRAIN OF THE BERKSHIRES/WORCESTER HILLS/MONADNOCKS...WITH A TRACE
TO AN INCH ELSEWHERE EXCEPT COASTAL COMMUNITIES. FOR AREAS MIXING
OVER TO RAIN...INITIAL SNOW ACCUMS WILL ALL BUT WASH AWAY.
A FINAL AND IMPORTANT NOTE...FORECAST GUIDANCE ALL BUT AGREES ON
SOME DRYING WITHIN THE BETTER SNOW GROWTH REGION ROUGHLY FOR AREAS
ALONG AND SOUTH OF THE MASS-PIKE BETWEEN NOW UNTIL 10 AM. HAVE
HINTED AT LIGHT FREEZING DRIZZLE MIXING IN WITH LIGHT SNOW.
HIGHS TODAY AROUND THE UPPER-20S TO LOW-30S /WARMEST CONDITIONS
ALONG THE IMMEDIATE SHORES...CAPE AND ISLANDS/.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM FRIDAY/...
TONIGHT....
HIGH PRES AND COLDER AIR WORKING IN. WHILE THE SYSTEM CLEARS OUT...
WILL SEE SOME LOW- TO MID-LEVEL CLOUDS LINGER ASSOCIATED WITH FETCH
OFF THE LAKES AND ADDITIONAL WEAK IMPULSES ROUNDING THE BROADER FLOW
REGIME ALOFT. COLD AIR ADVECTION THROUGH THE LOW-LEVELS ALLOWS FOR
STEEPENING LAPSE RATES. MIX-DOWN OF FASTER MOMENTUM CERTAINLY
POSSIBLE WITH GUSTS OF 20 TO 25 MPH...ESPECIALLY ALONG THE SOUTH-
SOUTHEAST COAST WITH ADJACENT WARMER WATERS. NOT ARCTIC COLD...LOWS
AROUND THE UPPER-TEENS TO LOW-20S /WARMER ALONG IMMEDIATE SHORES/.
FRIDAY...
HIGH PRES CONTINUING TO BUILD...SHIFTING SOUTH AND EAST. WILL SEE
WESTERLY FLOW DIMINISH TURNING SOUTHWESTERLY...BECOMING LIGHT.
LINGERING LOW- TO MID-LEVEL CLOUDS WITH FETCH OFF THE LAKES. STILL
COLD WITH H925 TEMPS AROUND -4 TO -6C /H85 AROUND -10C/. HIGHS
AROUND THE LOW- TO MID-30S ANTICIPATED.
&&
.LONG TERM /FRIDAY NIGHT THROUGH WEDNESDAY/...
BIG PICTURE... UPPER LOW CENTERED OVER BAFFIN ISLAND/HUDSON BAY WITH
CYCLONIC FLOW OVER THE NORTHEAST USA WEAKENING EARLY IN THE
FORECAST...THEN STRENGTHENING AGAIN BY NEW YEARS EVE. THIS
CONTINUES TO FAVOR MODERATING TEMPS OVER THE WEEKEND...THEN A RETURN
TO BELOW NORMAL TEMPS EARLY NEXT WEEK. THE MAIN CHANGE IN THIS
PATTERN SEEMS TO BE A 24-HOUR DELAY IN THE ONSET OF NEXT WEEK/S
CHILL. THE UPPER JET AND SOUTHWEST FLOW DON/T MOVE EAST OF NEW
ENGLAND UNTIL MONDAY NIGHT.
MEANWHILE THE NORTHERN AND SOUTHERN UPPER JETS ARE NOW FORECAST TO
PHASE DURING SUNDAY...ALLOWING SOUTHERN STREAM SHORTWAVE TO TAP A
MORE PRONOUNCED BAROCLINIC ZONE AS IT MOVES PAST NEW ENGLAND. THE
PHASING SUGGESTS DEEPENING OF THE UPPER TROUGH TO OUR WEST RESULTING
IN MORE OF A SOUTHWEST FLOW ALOFT. THIS LEAVES ROOM FOR THE SURFACE
COASTAL LOW TO EDGE CLOSER TO THE COAST LATER SUNDAY/SUNDAY NIGHT.
THIS IS A STORMIER SCENARIO FOR US THAN WAS DEPICTED 24 HOURS AGO.
WE WILL NEED TO MONITOR THAT THIS SUDDEN CHANGE DOESN/T GO BACK THE
OTHER WAY JUST AS FAST.
MODELS... GFS AND ECMWF ARE SIMILAR WITH THEIR SURFACE ISOBARS/UPPER
CONTOURS/UPPER JET WIND SPEEDS THROUGH SUNDAY NIGHT. SMALL
DIFFERENCES DEVELOP MONDAY THROUGH WEDNESDAY. WE FAVOR A BLEND OF
THE LONG RANGE GUIDENCE.
THE DAILIES...
FRIDAY NIGHT-SATURDAY... COLD NORTHWEST FLOW FLATTENS TO A WEST-EAST
FLOW AS SHORTWAVES IN THE NORTHERN AND SOUTHERN STREAMS MOVE INTO
THE PLAINS. THE NORTHERN STREAM SUPPORTS A STALLED COLD FRONT ALONG
THE CANADIAN BORDER WITH LOW PRESSURE WAVES RIPPLING ALONG IT.
MEANWHILE HIGH PRESSURE IS IN PLACE ACROSS THE SOUTHEAST AND MID
ATLANTIC STATES. LIGHT FLOW AND DRY AIR WILL ALLOW FRIDAY NIGHT
TEMPS TO DIP INTO THE TEENS AND 20S. THEN THE MILDER AIR WILL START
FLOWING IN A WEST-SOUTHWEST FLOW. CLOUDS ASSOCIATED WITH THE
STALLED COLD FRONT WILL AFFECT NORTHERN NEW ENGLAND SATURDAY AND MAY
BRING PARTLY CLOUDY SKIES TO PARTS OF OUR AREA. BUT OVERALL IT WILL
BE A FAIR DAY WITH TEMPS REACHING THE UPPER 30S AND 40S.
SUNDAY-MONDAY... SOUTHERN STREAM LOW PRESSURE DEVELOPS OVER THE GULF
OF MEXICO LATE SATURDAY AND MOVES UP THE EAST COAST ON SUNDAY. AS
NOTED ABOVE...THE TWO JET STREAMS ARE NOW EXPECTED TO PHASE ON
SUNDAY ALLOWING THE COASTAL SYSTEM TO MOVE CLOSER TO THE COAST. IF
THIS VERIFIES...IT WILL ALLOW PRECIPITATION TO REACH MOST OR ALL OF
OUR AREA LATER SUNDAY AND SUNDAY NIGHT. TEMPS IN THE VERTICAL WILL
BE ABOVE FREEZING SOUTH OF THE MASS PIKE WHILE AREAS FARTHER NORTH
MAY HAVE TEMPS EITHER SIDE OF FREEZING. THIS WILL MEAN RAIN FOR OUR
SOUTHERN AREAS AND A RAIN/SNOW MIX IN THE NORTH...POSSIBLY ALL SNOW
IN SOUTHERN NH. THE CURRENT MODEL INFORMATION IS NOTICEABLY
DIFFERENT FROM THE INFO 24 HOURS AGO SO CONFIDENCE IS VERY LIMITED
FOR THIS FORECAST. ALSO SMALL CHANGES IN THE FLOW OVER THE NEXT 3-4
DAYS COULD PUSH THE RAIN TEMPERATURES FARTHER NORTH OR THE SNOW
TEMPERATURES FARTHER SOUTH. SO STAY TUNED. THE UPPER FLOW WILL
REMAIN OPEN TO THE EAST ALLOWING THE COASTAL STORM TO RACE OFF
THROUGH THE MARITIMES SUNDAY NIGHT. MONDAY LOOKS SUNNIER/DRIER AND
COOLER...BUT NOT UNSEASONABLY SO.
TUESDAY-WEDNESDAY... WITH THE UPPER JET MOVING OFFSHORE MONDAY
NIGHT...THE WAY WILL BE OPEN FOR ARCTIC AIR TO RETURN TO SOUTHERN
NEW ENGLAND. TEMPS AT 925 MB WILL BE 10C COLDER WITH VALUES TUESDAY
AT -12C TO -14C. FULLY MIXED THIS WOULD SUPPORT MAX TEMPS IN THE
20S. DEWPOINTS WILL DIVE TO THE SINGLE NUMBERS AND BELOW ZERO. THIS
WILL MAKE ROOM FOR NIGHTTIME MIN TEMPS IN THE SINGLE NUMBERS AND
LOWER TEENS.
&&
.AVIATION /08Z THURSDAY THROUGH MONDAY/...
FORECASTER CONFIDENCE LEVELS...
LOW...LESS THAN 30 PERCENT.
MODERATE...30 TO 60 PERCENT.
HIGH...GREATER THAN 60 PERCENT.
NEAR TERM /THROUGH FRIDAY/...HIGH CONFIDENCE.
9Z UPDATE...
MVFR CIGS FILTING ONSHORE AS WINDS ARE GRADUALLY VEERING E/SE TO S
LATER TODAY. THROUGH THE MORNING AND INTO MIDDAY...CONDITIONS
EXPECTED TO DETERIORATE TO MVFR/IFR...HOLDING THROUGH AFTERNOON.
WITH ANY -SN SUGGEST MVFR/IFR CIGS WITH IFR VSBYS...BETTER CHANCES
FOR IFR CIGS WILL BE SOUTH AND EAST. WITH ANY -RA...EXPECT GREATER
CHANCES FOR IFR CIGS...YET WITH MVFR VSBYS.
IMPROVEMENT BEGINS TOWARDS EVENING AS WINDS REVERT WESTERLY AND
BECOME BLUSTERY...GUSTS DEVELOPING OVERNIGHT INTO FRIDAY THE
STRONGEST OF WHICH WILL LIKELY IMPACT SHORELINE TERMINALS. LOW- TO
MID-LEVEL CLOUDS FEW-SCT WILL LIKELY FILTER ACROSS THE TERMINALS.
KBOS TAF...HIGH CONFIDENCE IN TAF. LOWER CONFIDENCE WITH EXACT
TIMING OF IMPACTS. INITIAL SNOW ACCUMS OF AROUND A TENTH OR TWO IN
THE MORNING WILL WASH AWAY AS SNOW MIXES OVER TO RAIN DURING THE
MORNING HOURS.
MAINLY VFR...BUT MVFR CIGS HOLDING OVER THE CAPE AND ISLANDS. BY
MORNING MOST TERMINALS WILL BEGIN TO DETERIORATE MVFR/IFR WITH
ONSET OF A RAIN/SNOW MIX. EXPECT MORE IFR CONDITIONS DUE TO VSBY
WITH -SN /BEST CHANCES OVER N-W INTERIOR TERMINALS WHEREAS RAIN IS
EXPECTED ELSEWHERE...LITTLE ACTIVITY FOR TERMINALS IN THE S CT
VALLEY/. IFR CIGS EXPECTED MORESO FOR E/SE TERMINALS.
WILL SEE PRESENT LIGHT N WINDS VEER S/SE THROUGH THURSDAY...
BACKING OUT OF THE WEST WITH PASSAGE OF DISTURBED WEATHER BY WHICH
TIME CONDITIONS IMPROVE BACK TO VFR. WEST WINDS WILL BE GUSTY AT
TIMES AROUND 25 KTS.
KBDL TAF...HIGH CONFIDENCE IN TAF. MUCH OF THE ACTIVITY STAYS EAST
OF THE TERMINAL. EXPECTING JUST SOME FLURRIES TO A BRIEF LIGHT
SNOW SHOWER THAT WILL YIELD AROUND A TRACE OF SNOW ACCUM AT MOST.
OUTLOOK...FRIDAY NIGHT THROUGH MONDAY
FRIDAY NIGHT THROUGH SUNDAY MORNING...HIGH CONFIDENCE. VFR.
SUNDAY AFTERNOON THROUGH MONDAY...MODERATE CONFIDENCE. CIGS AND
VSBYS WILL LOWER TO MVFR IN DEVELOPING RAIN SUNDAY AFTERNOON AND
EVENING. PRECIPITATION MAY MIX WITH SNOW OR BECOME ALL SNOW IN
SOUTHERN NH AND PARTS OF NORTHERN MASS. IFR CONDITIONS POSSIBLE
SUNDAY NIGHT. PRECIPITATION ENDS BY MONDAY MORNING AND CONDITIONS
WILL IMPROVE TO VFR.
&&
.MARINE...
FORECASTER CONFIDENCE LEVELS...
LOW...LESS THAN 30 PERCENT.
MODERATE...30 TO 60 PERCENT.
HIGH...GREATER THAN 60 PERCENT.
NEAR TERM /THROUGH FRIDAY/...HIGH CONFIDENCE.
WILL SEE AN ENHANCEMENT OF FLOW AS AN AREA OF LOW PRES DEVELOPS S
OF NEW ENGLAND MIDDAY AND LIFTS NE INTO THE GULF OF MAINE BY
EVENING...GROWING STRONGER THROUGH ITS TRACK. WINDS VEERING E/SE
GRADUALLY TO S DURING THE DAY WILL AMPLIFY IN RESPONSE. SEAS
LIKELY TO BUILD TO 5 FEET OR GREATER BY MIDDAY...THUS SMALL-CRAFT
ADVISORIES ARE IN EFFECT.
ATTENDANT MIX OF RAIN AND SNOW INITIALLY CHANGING OVER TO ALL
RAIN THROUGH THE MORNING MAY YIELD VISIBILITY IMPACTS OVER THE
WATERS.
OVERNIGHT...COVERAGE OF SMALL-CRAFT ADVISORIES EXTENDS IN RESPONSE
TO WINDS BACKING OUT OF THE WEST BEHIND THE DEPARTING SYSTEM AND
BECOMING BLUSTERY WITH GUSTS UP TO 25 KTS. CONDITIONS CONTINUE
THROUGH FRIDAY. SEAS BUILDING OVER THE OUTER WATERS...5 TO 7 FEET.
OUTLOOK...FRIDAY NIGHT THROUGH MONDAY
MODERATE CONFIDENCE
FRIDAY NIGHT-SATURDAY...WEST TO SOUTHWEST WINDS MAY GUST NEAR 25
KNOTS. SEAS WILL SUBSIDE BELOW 5 FEET FRIDAY NIGHT...BUT THEN BUILD
ON SATURDAY TO 5-7 FEET ESPECIALLY ON THE OUTER WATERS. A SMALL
CRAFT ADVISORY MAY BE NEEDED FOR PARTS OF THE MASS AND RI WATERS.
SUNDAY...COASTAL LOW PRESSURE MOVES UP THE EAST COAST. VARIABLE
WINDS WILL BECOME NORTHEAST LATE SUNDAY AND THEN NORTHWEST MONDAY.
SPEEDS WILL BE AROUND 25 KNOTS...WHILE THE EXPOSED WATERS WILL SEE
SEAS BUILD TO 5 TO 7 FEET. SMALL CRAFT ADVISORY MAY BE NEEDED FOR
PARTS OF THE MASS AND RI WATERS.
&&
.BOX WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
MA...NONE.
NH...NONE.
RI...NONE.
MARINE...SMALL CRAFT ADVISORY FROM 6 PM THIS EVENING TO 2 AM EST FRIDAY
FOR ANZ231-232-251.
SMALL CRAFT ADVISORY FROM 6 PM THIS EVENING TO MIDNIGHT EST
TONIGHT FOR ANZ233-234.
SMALL CRAFT ADVISORY FROM 4 PM THIS AFTERNOON TO 2 AM EST
FRIDAY FOR ANZ235-237.
SMALL CRAFT ADVISORY FROM 1 PM THIS AFTERNOON TO 7 PM EST
FRIDAY FOR ANZ250-254>256.
&&
$$
SYNOPSIS...WTB/SIPPRELL
NEAR TERM...SIPPRELL
SHORT TERM...SIPPRELL
LONG TERM...WTB
AVIATION...WTB/SIPPRELL
MARINE...WTB/SIPPRELL
AREA FORECAST DISCUSSION
NWS TAUNTON MA
315 AM EST THU DEC 26 2013
.SYNOPSIS...
A WEAK AND QUICK DISTURBANCE WILL BRING A MIX OF RAIN AND SNOW FOR
THE REGION TODAY. WHILE COOL FOR FRIDAY...MILDER CONDITIONS MOVE
IN FOR THE WEEKEND. LOW PRESSURE WILL MOVE NORTHEAST FROM THE
GULF OF MEXICO AND INTENSIFY NEAR NANTUCKET SUNDAY NIGHT...THEN
SOUTH OF NOVA SCOTIA MONDAY MORNING. FRIGID AIR WILL INVADE THE
REGION MONDAY AND TUESDAY. LOW PRESSURE TO OUR WEST COULD POSSIBLY
LEAD TO LIGHT SNOW AROUND NEW YEARS DAY.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
STRONGER NORTHERN STREAM IMPULSE THROUGH THE BROADER TROUGH REGIME
INVOKES A WEAK AREA OF LOW PRES SOUTH AND OFFSHORE OF NEW ENGLAND
WITHIN THE BETTER BAROCLINIC ZONE BY MIDDAY...QUICKLY MOVING
NORTHEASTWARD AND AMPLIFYING ACROSS THE GULF OF MAINE BY EVENING.
DURING THIS AMPLIFICATION...ATTENDANT DYNAMICS AND JET STREAK
ENHANCE SOUTH-SOUTHWESTERLY LOW- TO MID-LEVEL FLOW RESULTING IN
LOCALIZED MOISTURE CONVERGENCE ALONG THE LEADING WARM-FRONT /N-NE
QUADRANT OF THE SURFACE LOW/ WHERE FRONTOGENESIS/ISENTROPIC FORCING
IS MAXIMIZED.
ALREADY THIS MORNING...RADAR ECHOES ARE BUILDING ACROSS UPSTATE NY
OUT AHEAD OF THE NORTHERN STREAM IMPULSE...WHILE PER SATELLITE
TRENDS...LOW CLOUDS AND MOISTURE ARE BEING DRAWN UP FROM THE SOUTH.
SO WITH CERTAINTY...THE HEAVIEST OF PRECIP IMPACTS E/SE PORTIONS OF
SOUTHERN NEW ENGLAND WITH ONE TO TWO TENTHS /THE GREATEST OF WHICH
WILL BE ACROSS THE EASTERN CAPE AND NANTUCKET/. LESSER AMOUNTS
EXPECTED FOR THE NORTH AND WEST INTERIOR. CLOUDS ON THE INCREASE
SOUTH AND WEST PRESENTLY WILL BEGIN TO CLEAR OUT LATE.
BUT SOME QUESTION AS TO HOW QUICKLY ARCTIC AIR WILL SCOUR OUT. NOT A
ROBUST SYSTEM AND ONSHORE SOUTHERLY FLOW WILL BE LIGHT. WHILE MILDER
AIR WILL WORK IN SOUTH TO NORTH...CONSIDERING HOW LONG WE HAVE BEEN
IN AN ARCTIC GRIP...FEEL THE PROGRESSION OF MILDER AIR WILL BE SLOW
AGAINST THE ARCTIC AIRMASS. SUSPECT COASTAL LOCATIONS AND ADJACENT
PLAINS WILL WARM ABOVE FREEZING...WHILE INTERIOR LOCALES /ESPECIALLY
THOSE WITH A REMAINING SNOWPACK/ WILL STAY AT OR BELOW FREEZING
THROUGHOUT THE EVENT. WHILE THE HRRR MAY BE TOO COLD...THE WRF-ARW
2M TEMPS ARE A GOOD APPROXIMATION AS TO THINKING.
IN THE END...SNOW IS EXPECTED INITIALLY MIXING OVER TO RAIN FOR
COASTAL COMMUNITIES AND ADJACENT PLAINS...WITH MAINLY ALL SNOW FOR
THE NORTHERN AND WESTERN INTERIOR /NORTH AND WEST OF I-84 TO I-90 TO
I-95 AS AN APPROXIMATION/. ROUGHLY 1 TO 2 INCHES FOR THE HIGHER
TERRAIN OF THE BERKSHIRES/WORCESTER HILLS/MONADNOCKS...WITH A TRACE
TO AN INCH ELSEWHERE EXCEPT COASTAL COMMUNITIES. FOR AREAS MIXING
OVER TO RAIN...INITIAL SNOW ACCUMS WILL ALL BUT WASH AWAY.
A FINAL AND IMPORTANT NOTE...FORECAST GUIDANCE ALL BUT AGREES ON
SOME DRYING WITHIN THE BETTER SNOW GROWTH REGION ROUGHLY FOR AREAS
ALONG AND SOUTH OF THE MASS-PIKE BETWEEN NOW UNTIL 10 AM. HAVE
HINTED AT LIGHT FREEZING DRIZZLE MIXING IN WITH LIGHT SNOW.
HIGHS TODAY AROUND THE UPPER-20S TO LOW-30S /WARMEST CONDITIONS
ALONG THE IMMEDIATE SHORES...CAPE AND ISLANDS/.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM FRIDAY/...
TONIGHT....
HIGH PRES AND COLDER AIR WORKING IN. WHILE THE SYSTEM CLEARS OUT...
WILL SEE SOME LOW- TO MID-LEVEL CLOUDS LINGER ASSOCIATED WITH FETCH
OFF THE LAKES AND ADDITIONAL WEAK IMPULSES ROUNDING THE BROADER FLOW
REGIME ALOFT. COLD AIR ADVECTION THROUGH THE LOW-LEVELS ALLOWS FOR
STEEPENING LAPSE RATES. MIX-DOWN OF FASTER MOMENTUM CERTAINLY
POSSIBLE WITH GUSTS OF 20 TO 25 MPH...ESPECIALLY ALONG THE SOUTH-
SOUTHEAST COAST WITH ADJACENT WARMER WATERS. NOT ARCTIC COLD...LOWS
AROUND THE UPPER-TEENS TO LOW-20S /WARMER ALONG IMMEDIATE SHORES/.
FRIDAY...
HIGH PRES CONTINUING TO BUILD...SHIFTING SOUTH AND EAST. WILL SEE
WESTERLY FLOW DIMINISH TURNING SOUTHWESTERLY...BECOMING LIGHT.
LINGERING LOW- TO MID-LEVEL CLOUDS WITH FETCH OFF THE LAKES. STILL
COLD WITH H925 TEMPS AROUND -4 TO -6C /H85 AROUND -10C/. HIGHS
AROUND THE LOW- TO MID-30S ANTICIPATED.
&&
.LONG TERM /FRIDAY NIGHT THROUGH WEDNESDAY/...
THE BIG PICTURE...
LOOKS LIKE THREE MAIN WEATHER EVENTS FOR THE EXTENDED RANGE.
THESE INCLUDE A STORM SUNDAY NIGHT INTO EARLY MONDAY...A BLAST OF
COLD AIR MONDAY INTO TUESDAY...POSSIBLY SOME LIGHT SNOW NEW YEARS
DAY...
THE LONG TERM FORECAST PERIOD BEGINS FRIDAY WITH A STRONG UPPER LOW
OVER BAFFIN BAY CANADA AND BRISK NORTHWEST FLOW ALOFT OVER NEW
ENGLAND. THE FLOW SPLITS IN THE SOUTHERN PLAINS WITH A SEPARATE
UPPER LOW OVER OKLAHOMA/TEXAS. AT THE SURFACE...SPRAWLING HIGH
PRESSURE FROM THE SOUTHERN PLAINS TO THE MID ATLANTIC WILL PROVIDE
QUIET WEATHER WITH MODERATING TEMPERATURES TO SOUTHERN NEW ENGLAND
FRIDAY AND SATURDAY. THIS SOUTHERN STREAM UPPER LOW IS FORECAST TO
EJECT NORTHEASTWARD SPAWNING LOW PRESSURE IN THE GULF OF MEXICO THAT
INTENSIFIES SOUTHEAST OF NEW ENGLAND SUNDAY NIGHT. A COLD BLAST OF
ARCTIC AIR WILL FOLLOW ON BRISK NORTHWEST WINDS MONDAY. IT WILL
REMAIN COLD INTO MIDWEEK AT WHICH TIME LOW PRESSURE SYSTEM AND THE
WARM ADVECTION IN ADVANCE OF IT WILL MOVE FROM THE LOWER GREAT LAKES
TOWARD NORTHERN NEW ENGLAND...PERHAPS BRINGING SOME LIGHT SNOW.
IT SHOULD BE NOTED THAT INCREDIBLY WIDE FLUCTUATIONS IN MODEL
FORECASTS HAVE BEEN OCCURRING JUST BEYOND OUR CURRENT FORECAST
PERIOD...FOR THE END OF NEXT WEEK. THIS IS IMPORTANT BECAUSE
ASTRONOMICAL TIDES WILL BE VERY HIGH AND ANY STRONG WINDS COULD LEAD
TO THE POSSIBILITY OF COASTAL FLOODING. THE ATMOSPHERIC DYNAMICS ARE
FORECAST TO BE QUITE STRONG BY THE END OF NEXT WEEK. THE QUESTION IS
WHETHER A MASSIVE COLD OUTBREAK/UPPER LOW PRESSURE IN CANADA WILL
PLUNGE SOUTH INTO THE U.S. AND HOW FAR SOUTHWARD. FOR EXAMPLE THE
06Z GFS RUN WAS DRASTIC WITH COLD AIR PLUNGING TO THE DEEP SOUTH AND
SPINNING UP AN INTENSE STORM OVER NEW ENGLAND...NOW THE 12Z GFS RUN
KEEPS IT IN CANADA. THE 00Z ECMWF RUN REALLY WENT TO TOWN WITH
ARCTIC AIR INTO THE DEEP SOUTH AND A 190+ KNOT JET AT 300 MB
SPAWNING AN INTENSE NORTHEAST STORM. THE 12Z ECMWF STILL DEPICTS AN
INTENSE LOW BUT MORE FOR THE NORTHERN NEW ENGLAND/CANADIAN BORDER
WITH COLD AIR HEADED HERE AND NOT THE DEEP SOUTH. STAY TUNED.
THE DAILIES...
FRIDAY...
WITH STRONG HIGH PRESSURE TO OUR SOUTH...EXPECT PARTLY TO MOSTLY
SUNNY SKIES. WINDS WILL SHIFT FROM NORTHWEST TO SOUTHWEST. STILL
VERY COLD WITH 850 MB TEMPERATURES STILL -8C TO -10C. HIGHS IN THE
30S. LOWS FRIDAY NIGHT IN THE TEENS AND 20S.
SATURDAY...
HIGH PRESSURE SHIFTS OFF THE MID ATLANTIC COAST AND OUT TO SEA.
SOUTHWEST WINDS OVER SOUTHERN NEW ENGLAND HELP USHER MILDER AIR
INTO THE REGION. 850 MB TEMPERATURES WARM ALL THE WAY TO +4C TO
+6C BY SAT EVENING. HAVE GONE A FEW DEGREES ABOVE MODEL CONSENSUS
FOR AFTERNOON HIGHS...IN THE 40S EVERYWHERE. LOWS SATURDAY NIGHT
IN THE 20S TO MID 30S EXCEPT UPPER 30S ON THE ISLANDS.
SUNDAY AND SUNDAY NIGHT...
THE UPPER ENERGY FROM THE OK/TX LOW EJECTS NORTHEASTWARD. SURFACE
LOW PRESSURE IS FORECAST TO TRACK FROM THE GULF OF MEXICO UP THE
EASTERN SEABOARD...AND BEGIN TO INTENSIFY OVER THE BENCHMARK OF
40N/70W AND STRENGTHEN FURTHER AS IT QUICKLY MOVES OUT TO SEA
SOUTH OF NOVA SCOTIA BY DAYBREAK MONDAY. THE 12Z ECMWF MODEL IS
VERY INTENSE WITH THIS STORM AND HAS MUCH MORE MOISTURE ASSOCIATED
WITH IT THAN THE GFS AND CANADIAN MODELS. THE GFS IS QUICK...WITH
CLEARING ABOUT 6-12 HOURS SOONER THAN THE ECMWF. HAVE SIDED MORE
WITH THE SLOWER ECMWF WHICH HAS BEEN CONSISTENT WITH THIS FEATURE
OVER THE PAST FEW RUNS. HAVE USED ECMWF WINDS INSTEAD OF MODEL
CONSENSUS FOR THE PERIOD FROM 18Z SUNDAY TO 12Z MONDAY. THE GOOD
NEWS IS THAT MOST OF SUNDAY WILL BE DRY ALLOWING TEMPERATURES TO
WARM INTO THE 40S AGAIN. THE BEST CHANCES OF RAIN MOVE IN FROM
SOUTH TO NORTH LATE IN THE DAY OR EVENING.
THERMAL PROFILES ON THE ECMWF HOWEVER MAY PRESENT A PROBLEM AS THE
STORM PROGRESSES. LOW LEVEL THICKNESSES AND 850 MB TEMPERATURES MAY
COOL ENOUGH TO CHANGE RAIN OVER TO SNOW OR PERHAPS A BRIEF PERIOD OF
FREEZING RAIN IN THE WESTERN PORTIONS OF THE AREA...BUT THE HIGHEST
QPF IS IN THE EAST...WHERE IT WILL BE RAIN. NOT EXPECTING MUCH IF
ANY ACCUMULATION IN THE WEST...AND IF THE GFS IS RIGHT...IT WILL END
THERE BEFORE ANY CHANGEOVER.
MONDAY AND TUESDAY...
ARCTIC AIR BLASTS INTO THE REGION MONDAY AFTERNOON AND NIGHT...
WITH 850 MB TEMPERATURES DIVING TO -16C TO -18C MONDAY NIGHT...AND
CONTINUING DOWN TO -20C TO -22C TUESDAY. AM FORECASTING LOWS
MONDAY NIGHT IN THE SINGLE DIGITS IN SOUTHERN NH AND NORTHERN MA
AND TEENS ELSEWHERE EXCEPT LOWER 20S ON THE ISLANDS. BREEZY
CONDITIONS WILL MAKE IT FEEL EVEN COLDER. HIGHS ONLY IN THE 20S
TUESDAY. LOWS ON NEW YEARS EVE/TUESDAY NIGHT/ RANGING FROM 7
NORTHWEST TO 17 SOUTHEAST WITH LOWER 20S ON THE ISLANDS. THERE IS
A CHANCE...ESPECIALLY ON TUESDAY THAT THE OUTER CAPE COULD AGAIN
SEE OCEAN EFFECT SNOW SHOWERS...EVEN THOUGH THE SURFACE FLOW IS
NORTHWESTERLY.
WEDNESDAY/NEW YEARS DAY...
LOW CONFIDENCE AT THIS TIME. MODEL CONSENSUS IS THAT LOW PRESSURE
MOVES FROM THE GREAT LAKES TO NORTHERN NEW ENGLAND MIDWEEK. WARM
ADVECTION PRECIPITATION...DEFINITELY IN THE FORM OF SNOW...IS
POSSIBLE AHEAD OF THIS. IT WOULD BE ON THE LIGHT SIDE. BECAUSE OF
VERY DISPARATE MODEL SOLUTIONS WITH THIS AND THE EVOLVING DEEP
UPPER LOW BEHIND THIS STORM FOR LATE NEXT WEEK...HAVE OPTED TO
ONLY INCLUDE SLIGHT CHANCE PROBABILITIES FOR WED AT THIS POINT.
THIS MAY EVENTUALLY BE INCREASING AS TIME GETS CLOSER. NOT QUITE
AS COLD WED WITH HIGHS UPPER 20S TO MID 30S.
&&
.AVIATION /08Z THURSDAY THROUGH MONDAY/...
FORECASTER CONFIDENCE LEVELS...
LOW...LESS THAN 30 PERCENT.
MODERATE...30 TO 60 PERCENT.
HIGH...GREATER THAN 60 PERCENT.
NEAR TERM /THROUGH FRIDAY/...HIGH CONFIDENCE.
9Z UPDATE...
MVFR CIGS FILTING ONSHORE AS WINDS ARE GRADUALLY VEERING E/SE TO S
LATER TODAY. THROUGH THE MORNING AND INTO MIDDAY...CONDITIONS
EXPECTED TO DETERIORATE TO MVFR/IFR...HOLDING THROUGH AFTERNOON.
WITH ANY -SN SUGGEST MVFR/IFR CIGS WITH IFR VSBYS...BETTER CHANCES
FOR IFR CIGS WILL BE SOUTH AND EAST. WITH ANY -RA...EXPECT GREATER
CHANCES FOR IFR CIGS...YET WITH MVFR VSBYS.
IMPROVEMENT BEGINS TOWARDS EVENING AS WINDS REVERT WESTERLY AND
BECOME BLUSTERY...GUSTS DEVELOPING OVERNIGHT INTO FRIDAY THE
STRONGEST OF WHICH WILL LIKELY IMPACT SHORELINE TERMINALS. LOW- TO
MID-LEVEL CLOUDS FEW-SCT WILL LIKELY FILTER ACROSS THE TERMINALS.
KBOS TAF...HIGH CONFIDENCE IN TAF. LOWER CONFIDENCE WITH EXACT
TIMING OF IMPACTS. INITIAL SNOW ACCUMS OF AROUND A TENTH OR TWO IN
THE MORNING WILL WASH AWAY AS SNOW MIXES OVER TO RAIN DURING THE
MORNING HOURS.
MAINLY VFR...BUT MVFR CIGS HOLDING OVER THE CAPE AND ISLANDS. BY
MORNING MOST TERMINALS WILL BEGIN TO DETERIORATE MVFR/IFR WITH
ONSET OF A RAIN/SNOW MIX. EXPECT MORE IFR CONDITIONS DUE TO VSBY
WITH -SN /BEST CHANCES OVER N-W INTERIOR TERMINALS WHEREAS RAIN IS
EXPECTED ELSEWHERE...LITTLE ACTIVITY FOR TERMINALS IN THE S CT
VALLEY/. IFR CIGS EXPECTED MORESO FOR E/SE TERMINALS.
WILL SEE PRESENT LIGHT N WINDS VEER S/SE THROUGH THURSDAY...
BACKING OUT OF THE WEST WITH PASSAGE OF DISTURBED WEATHER BY WHICH
TIME CONDITIONS IMPROVE BACK TO VFR. WEST WINDS WILL BE GUSTY AT
TIMES AROUND 25 KTS.
KBDL TAF...HIGH CONFIDENCE IN TAF. MUCH OF THE ACTIVITY STAYS EAST
OF THE TERMINAL. EXPECTING JUST SOME FLURRIES TO A BRIEF LIGHT
SNOW SHOWER THAT WILL YIELD AROUND A TRACE OF SNOW ACCUM AT MOST.
OUTLOOK...FRIDAY THROUGH SUNDAY...
FRIDAY THROUGH SATURDAY...HIGH CONFIDENCE. VFR.
SUNDAY...MODERATE CONFIDENCE. VFR IN THE MORNING AND EARLY
AFTERNOON. MVFR CIGS MOVING IN FROM SOUTH TO NORTH LATE IN THE
AFTERNOON AND OVERSPREADING THE ENTIRE REGION BY EVENING. IFR
CONDITIONS POSSIBLE IN RAIN AND FOG...POSSIBLY CHANGING TO SNOW IN
THE WESTERN HALF OF THE REGION BEFORE ENDING BY DAYBREAK MONDAY.
&&
.MARINE...
FORECASTER CONFIDENCE LEVELS...
LOW...LESS THAN 30 PERCENT.
MODERATE...30 TO 60 PERCENT.
HIGH...GREATER THAN 60 PERCENT.
NEAR TERM /THROUGH FRIDAY/...HIGH CONFIDENCE.
WILL SEE AN ENHANCEMENT OF FLOW AS AN AREA OF LOW PRES DEVELOPS S
OF NEW ENGLAND MIDDAY AND LIFTS NE INTO THE GULF OF MAINE BY
EVENING...GROWING STRONGER THROUGH ITS TRACK. WINDS VEERING E/SE
GRADUALLY TO S DURING THE DAY WILL AMPLIFY IN RESPONSE. SEAS
LIKELY TO BUILD TO 5 FEET OR GREATER BY MIDDAY...THUS SMALL-CRAFT
ADVISORIES ARE IN EFFECT.
ATTENDANT MIX OF RAIN AND SNOW INITIALLY CHANGING OVER TO ALL
RAIN THROUGH THE MORNING MAY YIELD VISIBILITY IMPACTS OVER THE
WATERS.
OVERNIGHT...COVERAGE OF SMALL-CRAFT ADVISORIES EXTENDS IN RESPONSE
TO WINDS BACKING OUT OF THE WEST BEHIND THE DEPARTING SYSTEM AND
BECOMING BLUSTERY WITH GUSTS UP TO 25 KTS. CONDITIONS CONTINUE
THROUGH FRIDAY. SEAS BUILDING OVER THE OUTER WATERS...5 TO 7 FEET.
OUTLOOK...FRIDAY THROUGH SUNDAY...
MODERATE CONFIDENCE
FRI AND SAT...WEST-NORTHWEST WINDS MAY GUST TO 20 TO 25 KT FRI.
ON SAT...SOUTHWEST WINDS MAY GUST TO AROUND 20 KT. SEAS JUST BELOW
SCA CRITERIA OF 5 FT ON THE OUTER WATERS FRI-SAT. A SMALL CRAFT
ADVISORY MAY BE NEEDED FOR PARTS OF THE WATERS.
A STORM SYSTEM TRACKING UP THE COAST SUNDAY WILL INTENSIFY
SOUTHEAST OF NEW ENGLAND SUNDAY NIGHT AND HEAD TOWARD NOVA SCOTIA
EARLY MONDAY. SMALL CRAFT ADVISORIES WILL LIKELY BE NEEDED. WINDS
WILL BE DEPENDENT ON THE EXACT TRACK OF THE LOW BUT SHOULD SWING
TO THE NORTHEAST AT SOME POINT SUNDAY NIGHT AND MAY GUST TO 25-30
KT. SEAS MAY BUILD TO 6 TO 10 FT OVER THE OUTER
WATERS...ESPECIALLY THE SOUTHEASTERN WATERS.
&&
.BOX WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
MA...NONE.
NH...NONE.
RI...NONE.
MARINE...SMALL CRAFT ADVISORY FROM 6 PM THIS EVENING TO 2 AM EST FRIDAY
FOR ANZ231-232-251.
SMALL CRAFT ADVISORY FROM 6 PM THIS EVENING TO MIDNIGHT EST
TONIGHT FOR ANZ233-234.
SMALL CRAFT ADVISORY FROM 4 PM THIS AFTERNOON TO 2 AM EST
FRIDAY FOR ANZ235-237.
SMALL CRAFT ADVISORY FROM 1 PM THIS AFTERNOON TO 7 PM EST
FRIDAY FOR ANZ250-254>256.
&&
$$
SYNOPSIS...SIPPRELL/GAF
NEAR TERM...SIPPRELL
SHORT TERM...SIPPRELL
LONG TERM...GAF
AVIATION...SIPPRELL/GAF
MARINE...SIPPRELL/GAF
AREA FORECAST DISCUSSION...UPDATED
NWS JACKSON KY
335 AM EST THU DEC 26 2013
.SHORT TERM...(TODAY THROUGH FRIDAY)
ISSUED AT 335 AM EST THU DEC 26 2013
07Z SFC ANALYSIS SHOWS A MOSTLY DRY COLD FRONT CROSSING EAST
KENTUCKY. THIS IS ACCOMPANIED BY A LOWER DECK OF CLOUDS AND SOME
RETURNS ON RADAR...MOSTLY VIRGA. LOWER CLOUDS...NEAR MVFR...TRAIL
THIS BOUNDARY AND WILL MOVE OVER THE NORTHERN TWO THIRDS OF THE CWA
INTO THE FIRST PART OF THE MORNING. THIS SHOULD KEEP TEMPERATURES
FROM FALLING MUCH FURTHER THROUGH THE AREA INTO DAWN. CURRENTLY THEY
VARY FROM THE UPPER 20S IN SOME VALLEYS TO THE MID 30S ON THE
RIDGES...WHILE DEWPOINTS ARE GENERALLY IN THE LOW AND MID 20S.
THE MODELS ARE IN GOOD ENOUGH AGREEMENT ALOFT THROUGH THE SHORT TERM
AS THEY ALL TAKE A SHARP SHORTWAVE NORTHEAST AND AWAY FROM THE OHIO
VALLEY TODAY. LATER...ANOTHER RIPPLE MOVES THROUGH THE BASE OF THE
RETREATING LARGE EAST CANADIAN TROUGH...PASSING HARMLESSLY THROUGH
THE AREA MIDDAY FRIDAY. HEIGHTS WILL THEN RISE OVER THE STATE AHEAD
OF A BROAD AND UNCONSOLIDATED AREA OF LOWER ONES ASSOCIATED WITH THE
POOLING ENERGY OVER SOUTH CENTRAL TEXAS. THE MODELS ARE HAVING THE
MOST DIFFICULTIES WITH THIS FEATURE AS THE NAM IS OUT OF STEP WITH
THE OTHERS IN KEEPING THE RESULTANT MID LEVEL LOW WEAKER AND A NOTCH
FURTHER EAST THAN CONSENSUS. THESE DIFFERENCES WILL AFFECT THE
FORECAST OVER THE WEEKEND...BEYOND THE SHORT TERM SO THE NAM12 WAS
PRIMARILY USED...ALONG WITH THE LATEST HRRR FOR THE NEAR TERM WX...
TO GUIDE THIS PART OF THE FORECAST.
SENSIBLE WEATHER WILL FEATURE A FLEETING CHANCE OF MAINLY FLURRIES
PASSING THROUGH FAR EAST KENTUCKY OVER THE NEXT COUPLE OF HOURS.
OTHERWISE...IT WILL BE A DRY AND QUIET FORECAST TO END THE WORK WEEK
AS SFC HIGH PRESSURE IS BUFFETED BY PASSING MID LEVEL WAVES AND
THEIR SFC REFLECTIONS TO THE NORTH OF THE AREA. THIS WILL BE NOTED
MAINLY IN TIMES OF MID AND HIGH CLOUDS BRUSHING PAST THE CWA.
TEMPERATURES THROUGH EAST KENTUCKY WILL BE SEASONABLY NEAR NORMAL
WHILE WE AWAIT THE SOUTHERN DEVELOPMENT FOR A SHOT AT A RETURN OF
PCPN LATER IN THE WEEKEND.
FOLLOWED THE CONSSHORT AND ITS BC PARTNER FOR T...TD...AND WINDS
THROUGH 12Z FRIDAY WITH SOME BLENDING IN WITH THE DIURNAL FROM THE
NAM12 FOR HOURLY TEMPS. OTHERWISE...THE CONSALL WAS USED AS A
STARTING POINT. DID ADD IN SOME MINOR RIDGE AND VALLEY TEMPERATURE
DIFFERENCES TONIGHT WHILE KEEPING POPS IN THE LOW SINGLE DIGITS AT
BEST...IN LINE WITH MOS...OUTSIDE OF THE NEXT FEW HOURS IN THE FAR
EAST.
.LONG TERM...(FRIDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 330 AM EST THU DEC 26 2013
THE BEGINNING OF THE EXTENDED PERIOD /12Z SATURDAY/ WILL HOST ZONAL
FLOW ALOFT AND SURFACE HIGH PRESSURE...MAKING FOR CLEAR SKIES IN THE
MORNING. HOWEVER...THIS SET UP WILL BE SHORT LIVED...AS TWO SYSTEMS
WILL BEGIN TO INTERACT ON EASTERN KY OVER THE NEXT 24 TO 36 HOURS.
THE FIRST OF THESE SYSTEMS...A STRONG UPPER LEVEL SHORTWAVE ACROSS
THE SOUTHERN PLAINS MOVING SLOWLY NEWARD. A SURFACE LOW PRESSURE
SYSTEM WILL DEVELOP SLIGHTLY EASTWARD OF THE UPPER TROUGH...PULLING
IN MOISTURE OFF THE GULF OF MEXICO ACROSS THE SOUTHERN STATES AND
THEN INTO SOUTHERN AND EASTERN KY SATURDAY NIGHT/SUNDAY MORNING. THE
SECOND SHORTWAVE WILL BE SLIGHTLY WEAKER...MOVING IN JUST BEHIND AND
NORTH OF THE ORIGINAL WAVE. THIS WILL PUSH A COLD FRONT ACROSS
KY FROM THE NW MONDAY EVENING/NIGHT. OF THE TWO...EXPECT THE BEST
PRECIP CHANCES AND QPF TO COME FROM THE FIRST SYSTEM...BEGINNING
RIGHT BEFORE 6Z SUNDAY AND CONTINUING THROUGH SUNDAY
AFTERNOON/EVENING. THEN THE SECOND WAVE OF MOISTURE BEGINS TO HIT KY
FROM THE NORTH AND WEST SUNDAY NIGHT INTO MONDAY. THIS TIME THE
PRECIP WILL BE LIGHTER AND SCATTERED IN NATURE.
UNFORTUNATELY...MODELS ARE STILL NOT COMPLETELY AGREEING ON THEIR
TIMING AND SET UP...SO WILL CONTINUE WITH THE ALLBLEND OUTPUT AT
THIS TIME FOR POPS.
WITH A WARM PULL FROM THE SOUTH AHEAD OF THESE TWO SYSTEMS...TEMPS
WILL RISE TO ABOVE NORMALS SATURDAY AND SUNDAY /UPPER 40S AND LOW
50S/. HOWEVER...ONCE THE COLD FRONT ACCOMPANYING THE SECOND SYSTEM
PUSHES THROUGH...IT WILL USHER IN COLDER AIR FROM THE NW.
TEMPERATURE DIFFERENCES COULD BE AS MUCH AS 15 DEGREES COOLER FROM
SUNDAY INTO MONDAY...FALLING NEAR FREEZING FOR HIGHS. THIS
TEMPERATURE DROP WILL BE WHAT GOVERNS RAIN VS. SNOW WITH THIS SECOND
SYSTEM. AT PRESENT...HAVE ALL RAIN IN FORECAST UNTIL AROUND
MIDNIGHT...AT WHICH POINT A RAIN AND SNOW MIX WILL BE
POSSIBLE...BEFORE TEMPS DROP ENOUGH TO GOVERN ALL SNOW BY 9Z.
PROLONGED TIME PERIOD FOR WHICH ACCUMULATIONS COULD OCCUR COMPARED
TO PREVIOUS FORECAST...BUT DID DROP AMOUNTS SLIGHTLY IN THE WESTERN
HALF OF THE CWA. ANYWHERE BETWEEN A DUSTING TO A COUPLE TENTHS OF AN
INCH WILL BE POSSIBLE ACROSS MUCH THE CWA...WITH THE HIGHER TERRAIN
EXPECTED TO SEE A BIT MORE...BETWEEN A HALF AN INCH TO ONE INCH.
OBVIOUSLY THIS SYSTEM IS FAIRLY FAR OUT IN THE FORECAST...SO EXPECT
THESE TOTALS TO CONTINUE TO CHANGE AS WE GET CLOSER TO THE ONSET.
WITH A TROUGHING PATTERN SETTING UP ACROSS THE EASTERN U.S...COULD
SEE SEVERAL MORE SHORTWAVES MOVE THROUGH THE TROUGH OVER THE FEW
DAYS FOLLOWING. AT THIS TIME...MODEL SOLUTIONS ARE KEEPING ANY
MOISTURE RELATED TO THESE SHORTWAVES AWAY FROM EASTERN KY. THAT
BEING SAID...TUESDAY NIGHT/WEDNESDAY MORNING WILL BE A TIME FRAME TO
WATCH...AS ANY VARIATIONS SOUTHWARD FROM WHERE THE BLENDED RUN
PLACES THE SYSTEM...KJKL COULD SEE PRECIPITATION.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z THURSDAY NIGHT)
ISSUED AT 105 AM EST THU DEC 26 2013
MAINLY VFR CONDITIONS WILL PREVAIL THROUGH THE FORECAST PERIOD.
HOWEVER...TAF SITES WILL SEE A PERIOD OF MID LEVEL CLOUD COVER
DURING THE REST OF THE NIGHT AS A FRONTAL BOUNDARY SLIDES THROUGH
THE AREA. LOWEST POTENTIAL CIGS WILL BE AROUND 5K FT NORTH OF KJKL.
A FEW SNOW SHOWERS WILL BE POSSIBLE GENERALLY NORTH OF THE HAL ROGERS
PARKWAY. ANY ACTIVITY SHOULD BE TOO FAR NORTH TO AFFECT KLOZ OR
KSME...THOUGH. FOR KJKL AND KSJS HAVE INCLUDED A TEMPO FOR PERIOD OF
MVFR CIG SNOW THROUGH 10Z. WINDS WILL BE SOUTHWESTERLY TO START
BEFORE VEERING TO THE WEST...NORTHWEST LATER THURSDAY AT AROUND 5 KTS
IN THE WAKE OF A PASSING FRONT.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...GREIF
LONG TERM...JMW
AVIATION...GREIF
AREA FORECAST DISCUSSION...UPDATED
NWS JACKSON KY
105 AM EST THU DEC 26 2013
.UPDATE...
ISSUED AT 1250 AM EST THU DEC 26 2013
THE BAND OF LIGHT SNOW AND FLURRIES CONTINUES TO PUSH EAST SOUTHEAST
DEEPER INTO THE AREA. THANKS TO A LAYER OF DRY AIR AT THE SFC THIS
BAND HAS MOSTLY BEEN VIRGA. WITH THE FORECAST ON TRACK MAINLY JUST
TWEAKED LOWS THIS MORNING AND ADJUSTED THE NEXT SEVERAL HOURS OF T
AND TD GRIDS IN LINE WITH THE LATEST OBS AND TRENDS. THESE GRIDS HAVE
BEEN SENT TO THE NDFD AND WEB SERVERS.
UPDATE ISSUED AT 857 PM EST WED DEC 25 2013
RADAR RETURNS ARE INCREASING TO OUR NORTH AND A FEW SURFACE OBS HAVE
BEEN REPORTING LIGHT SNOW UNDERNEATH RECENTLY. SURFACE DEWPOINTS
HAVE TRENDED UPWARDS IN RECENT HOURS AND ARE NOW RUNNING HIGHER THAN
THE INHERITED FORECAST SO SUSPECT THERE WILL BE A LITTLE MORE
MOISTURE FOR THIS SYSTEM TO WORK WITH THAN PREVIOUSLY THOUGHT. A
RECENT HRRR RUN ALSO BROUGHT SOME SNOW SHOWERS ALL THE WAY SOUTH TO
JKL. SO...WILL INCREASE POPS A BIT OVER OUR NORTHERN TIER AND
MENTION A DUSTING POSSIBLE IN THE HWO...ALTHOUGH WITH TEMPS ABOVE
FREEZING...MINIMAL IMPACTS ARE EXPECTED.
UPDATE ISSUED AT 643 PM EST WED DEC 25 2013
WILL TWEAK THE TEMP CURVE A BIT TONIGHT AS EASTERN VALLEYS HAVE
ALREADY FALLEN BELOW FREEZING...WITH A FEW SPOTS ALREADY IN THE 20S.
I SUSPECT WE WILL EXPERIENCE OUR LOWS IN THESE VALLEYS THIS EVENING
WITH TEMPS LEVELING OFF OR EVEN RISING SEVERAL DEGREES LATER THIS
EVENING AS MID LEVEL CLOUDS MOVE OVERHEAD FROM THE WEST.
OTHERWISE...WATCHING A BAND OF WEAK RETURNS ON RADAR UP NEAR CINCY.
NO SURFACE REPORTS OF ANYTHING REACHING THE GROUND FROM THIS BUT NAM
TIME HEIGHTS SHOW LOW LEVELS MOISTENING UP ENOUGH TO JUSTIFY CURRENT
MENTION OF FLURRIES/ISOLATED SNOW SHOWERS OVER OUR NORTHERN COUNTIES
LATER TONIGHT.
&&
.SHORT TERM...(THIS EVENING THROUGH THURSDAY NIGHT)
ISSUED AT 246 PM EST WED DEC 25 2013
TEMPERATURES REBOUNDED WELL THROUGH THE DAY CLIMBING BACK INTO THE
LOWER 40S ACROSS SOUTHERN PORTIONS OF OUR CWA...MID 30S TO NEAR 40
ELSEWHERE UNDER STRONG SUNSHINE...CLEAR SKIES AND A LIGHT SOUTHERLY
RETURN FLOW.
MODELS ARE IN GOOD AGREEMENT THROUGH THE SHORT TERM PERIOD. SHORT
WAVE TROUGH WILL SWEEP ACROSS THE GREAT LAKES...OHIO VALLEY BETWEEN
NOW AND THURSDAY EVENING. CORRESPONDING SURFACE COLD FRONTAL BOUNDARY
WILL MOVE THROUGH EASTERN KENTUCKY BY EARLY THURSDAY MORNING...JUST
AFTER SUNRISE. FRONTAL FEATURES BECOME LESS DISTINCT WITH TIME. BUT
THERE WILL BE ENOUGH CLOUD COVER ASSOCIATED WITH THIS SYSTEM TO MAKE
THE OVERNIGHT LOW TEMPERATURE FORECAST MORE CHALLENGING THAN MIGHT
OTHERWISE BE. WITH DRY AIR IN PLACE DROPPED EVENING TEMPERATURES DOWN
PRETTY QUICKLY...ESPECIALLY IN OUR TYPICALLY COOLER EASTERN VALLEY
LOCATIONS. BUT TEMPERATURES SHOULD REBOUND AS CLOUDS ROLL INTO THE
AREA LATER TONIGHT. SKIES SHOULD ONCE AGAIN BEGIN TO CLEAR OUT
TOWARDS DAWN. WITH SOME WEAK CAA KICKING IN AND SKIES PARTIALLY
CLEARING TEMPS MAY DROP BACK DOWN FOR A FEW HOURS AGAIN EARLY
THURSDAY MORNING. NOT EXPECTING MUCH IN THE WAY OF PRECIPITATION WITH
THIS WEAK SYSTEM. ATTM CAN NOT RULE OUT SOME ISOLD SNOW SHOWER
ACTIVITY ALONG AND NORTH OF INTERSTATE 64 AND SOME FLURRIES IN OUR
EASTERN MOST COUNTIES. TEMPERATURE REBOUND NICELY AGAIN THURSDAY BUT
SHOULD BE JUST A COUPLE DEGREES COOLER THAN TODAY.
.LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 246 PM EST WED DEC 25 2013
AT THE START OF THE LONG TERM PORTION OF THE FORECAST THE UPPER
LEVEL FLOW WILL BE RELAXING WITH RISING HEIGHTS ACROSS OUR REGION.
THE NORTHERN STREAM WILL BECOME MORE ZONAL AS WE MOVE INTO THE
WEEKEND WHILE IN THE SOUTHERN STREAM A SHORT WAVE TROUGH WILL MOVE
INTO THE SOUTHERN PLAINS. AT THE SAME TIME THE CENTER OF SURFACE
HIGH PRESSURE WILL BE MOVING OFF TO OUR EAST. THIS ALL SPELLS
MODERATING TEMPERATURES AS WE MOVE INTO THE WEEKEND. YESTERDAY IT
APPEARED THAT THE SOUTHERN STREAM SYSTEM THAT MOVES INTO THE SE U.S.
THIS WEEKEND WOULD REMAIN TOO FAR SOUTH TO HAVE AN IMPACT ON OUR
LOCAL WEATHER. HOWEVER...THE 06Z AND 12Z GFS POINT TOWARDS A
PRECIPITATION CHANCE OVER AT LEAST THE SOUTHEAST PART OF THE
FORECAST AREA FROM SATURDAY NIGHT INTO SUNDAY. THIS IDEA IS
SUPPORTED BY THE 12Z ECMWF AS WELL. THE STANDARD BLENDED LOAD
PROVIDED SLIGHT CHANCE PRECIPITATION CHANCES FOR SATURDAY NIGHT IN
THE SOUTH AND CENTRAL PARTS OF THE FORECAST AREA...WITH A SLIGHT
CHANCE OVER THE CENTRAL AND EAST ON SUNDAY. WILL FOLLOW THIS IDEA.
MOST...IF NOT ALL OF ANY PRECIPITATION SHOULD BE IN THE FORM OF RAIN
SATURDAY NIGHT INTO SUNDAY...AND FOR NOW HAVE CARRIED ONLY RAIN IN THE
FORECAST. HOWEVER THERE IS AN OUTSIDE CHANCE THAT SOME VERY LIGHT
FROZEN PRECIPITATION...POSSIBLY SLEET...COULD OCCUR FOR A VERY BRIEF
PERIOD OF TIME AT PRECIPITATION ONSET LATE SATURDAY NIGHT.
THERE IS STILL GENERAL MODEL AGREEMENT WITH THE UPPER LEVEL TROUGH
DEEPENING ACROSS EASTERN NORTH AMERICA ONCE AGAIN AS WE MOVE INTO
THE EARLY PART OF NEXT WEEK. A COLD FRONT IS FORECAST TO MOVE ACROSS
THE AREA LATE SUNDAY...WITH A SLIGHT CHANCE FOR LIGHT RAIN AND SNOW
SUNDAY NIGHT AND A SLIGHT CHANCE FOR LIGHT SNOW ON MONDAY IN THE
SOUTHEAST. COLD BUT DRY CONDITIONS WILL THEN PERSIST INTO NEW YEARS
DAY.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z THURSDAY NIGHT)
ISSUED AT 105 AM EST THU DEC 26 2013
MAINLY VFR CONDITIONS WILL PREVAIL THROUGH THE FORECAST PERIOD.
HOWEVER...TAF SITES WILL SEE A PERIOD OF MID LEVEL CLOUD COVER
DURING THE REST OF THE NIGHT AS A FRONTAL BOUNDARY SLIDES THROUGH
THE AREA. LOWEST POTENTIAL CIGS WILL BE AROUND 5K FT NORTH OF KJKL.
A FEW SNOW SHOWERS WILL BE POSSIBLE GENERALLY NORTH OF THE HAL ROGERS
PARKWAY. ANY ACTIVITY SHOULD BE TOO FAR NORTH TO AFFECT KLOZ OR
KSME...THOUGH. FOR KJKL AND KSJS HAVE INCLUDED A TEMPO FOR PERIOD OF
MVFR CIG SNOW THROUGH 10Z. WINDS WILL BE SOUTHWESTERLY TO START
BEFORE VEERING TO THE WEST...NORTHWEST LATER THURSDAY AT AROUND 5 KTS
IN THE WAKE OF A PASSING FRONT.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...GREIF
SHORT TERM...RAY
LONG TERM...SBH
AVIATION...GREIF
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
1243 AM EST THU DEC 26 2013
.SHORT TERM...(THIS EVENING THROUGH THURSDAY)
ISSUED AT 446 PM EST WED DEC 25 2013
12Z RAOBS/LATEST WV IMAGERY AND RUC ANALYSIS SHOW UPR TROF CENTERED
OVER CENTRAL NAMERICA BTWN RDGING OVER THE ERN CONUS EXTENDING INTO
QUEBEC AND A STRONGER MEAN RDG OVER THE W. VERY CHILLY AIR LINGERS
OVER THE UPR LKS WITH H85 TEMPS IN THE -15C TO -20C RANGE. THERE ARE
SEVERAL SHRTWVS OF INTEREST EMBEDDED WITHIN THIS UPR TROF. THE FIRST
IS MOVING INTO WRN UPR MI EARLY THIS AFTN AND ACCOMPANIED BY AN AREA
OF COLDER CLD TOPS SHOWN ON IR STLT IMAGERY. IN CONCERT WITH SOME
DEEPER MSTR TO H5 SHOWN ON THE 12Z INL RAOB...SCT-NMRS -SHSN
IMPACTED MUCH OF THE CWA INTO EARLY THIS AFTN BEFORE LARGER SCALE
FORCING ASSOCIATED WITH THE SHRTWV THAT CAUSED THE SN LAST NGT/THIS
MRNG EXITED THE AREA. BUT LARGER SCALE QVECTOR DVGC HAS WEAKENED
THIS SHRTWV/WARMED CLD TOP TEMPS...DIMINISHING THE SHSN DURING THE
LAST COUPLE OF HRS. IN FACT...THERE HAS BEEN SOME CLRG THIS AFTN. A
SECOND SHRTWV IS DIGGING SSEWD THRU MANITOBA...ACCOMPANIED BY A
120KT H3 JET MAX. YET ANOTHER SHRTWV RIDING OVER THE TOP OF THE WRN
RDG IS PUSHING INTO BRITISH COLUMBIA.
MAIN FCST CONCERNS IN THE SHORT TERM ARE POPS/SN AMNTS/NEED FOR
HEADLINES ASSOCIATED WITH PARADE OF SHRTWS PASSING THRU THE UPR LKS
WITHIN THE PERSISTENT UPR TROF.
TNGT...AS SHRTWV DIGGING SEWD THRU MANITOBA PASSES INTO WI
TNGT...EXPECT A WSHFT TO THE NW TO DRIVE A LO PRES TROF ONSHORE.
ALTHOUGH THE 12Z NAM/GFS SHOW THE SHARPEST DPVA/H7-3 QVECTOR CNVGC
PASSING TO THE SW OF THE CWA CLOSER TO THE ACCOMPANYING H3 JET
CORE...NAM FCST SDNGS SHOW INVRN BASE AT CMX RISING TO NEAR 7K FT
THIS EVNG IN THE PRESENCE OF DEEPER MSTR. WITH VERY COLD LLVL AIR
LINGERING NEAR THE SFC...THE SFC WSHFT FM THE WSW OVER THE INTERIOR
WL NOT BE AS DRAMATIC AS OVER/NEAR LK SUP. THE RESULT WL BE
SHARPENED LAND BREEZE LLVL CNVGC NEAR LK SUP...FIRST OVER THE NW CWA
THIS EVNG AND THEN ALSO OVER THE FAR ERN CWA LATER. SINCE THE
ACCOMPANYING UVV IS CENTERED WITHIN THE DGZ AS SHOWN ON NAM FCST
SDNGS...SN/WATER RATIOS SHOULD BE AS HI AS 25-30:1. RELATIVELY LGT
WINDS NO HIER THAN 10-15 KTS SHOULD RESULT IN MINIMAL FRACTURING OF
THE SN FLAKES. CONSIDERING THE FRBL SN/WATER RATIOS AND POTENTIAL
FOR ENHANCED SN NEAR LAND BREEZE CNVGC ZONES...OPTED TO ISSUE AN LES
ADVY FOR THE KEWEENAW AND ALGER/LUCE COUNTIES FOR MAINLY THE AREAS
NEAR LK SUP E FM GRAND MARAIS TO CRISP POINT. ALSO CONCERNED AT
LEAST NORTHERN ONTONAGON COUNTY COULD SEE SOME HEAVIER SN TNGT...
BUT OPTED NOT TO INCLUDE THAT ZONE IN THE HEADLINE SINCE HEAVIER SN
IS LIKELY TO IMPACT ONLY THE RELATIVELY UNPOPULATED NRN PORTION OF
THIS COUNTY. SINCE THERE HAS BEEN PARTIAL CLRG OVER MUCH OF THE CWA
LATE THIS AFTN...OPTED TO LOWER MIN TEMPS A BIT WITH THE EXPECTATION
TEMPS COULD FALL QUICKLY BEFORE A WSHFT TOWARD THE NW ABV THE
SHALLOW COLD AIR NEAR THE SFC BRINGS IN MORE CLDS. BACKING LLVL FLOW
LATE AHEAD OF APRCHG HI PRES RDG/SHRTWV RDG FOLLOWING THE DEPARTING
DIGGING SHRTWV MAY BRING SOME PARTIAL CLRG/MORE UNMODIFIED ARCTIC
AIR TO THE INTERIOR W NEAR THE WI BORDER AS WELL.
THU...NEXT SHRTWV NOW TOPPING UPR RDG OVER WRN CANADA IS PROGGED TO
DIG SEWD THRU MN IN PERSISTENT NW FLOW ALF...WITH SHARPEST DEEP LYR
QVECTOR CNVGC PASSING TO THE SW OF UPR MI. LLVL WINDS ARE FCST TO
BACK SLOWLY TOWARD THE WSW OVER MAINLY THE WRN CWA THRU THE DAY
AHEAD OF THIS DISTURBANCE...SO LES SHOULD BECOME CONFINED TO MAINLY
THE KEWEENAW. ALTHOUGH SN TOTALS OVER KEWEENAW COUNTY TNGT MAY NOT
BE AS IMPRESSIVE AS IN HOUGHTON COUNTY...THE NRN PORTION OF THE
KEWEENAW WL LIKELY SEE MORE SN ON THU...ESPECIALLY LATER IN THE DAY.
WITH A MORE 300 DEGREE FLOW LINGERING THRU MUCH OF THE DAY TO THE
E...EXPECT THE MOST WDSPRD AND HEAVIER LES TO IMPACT ERN ALGER AND
THE THE N HALF OF LUCE COUNTY. OVER THE SCENTRAL...ARRIVAL OF HI
PRES RDG AHEAD OF THE SHRTWV WL BRING PARTIAL SUNSHINE FILTERED BY
MID/HI CLDS ASSOCIATED WITH THE MSTR STARVED SHRTWV.
.LONG TERM...(THURSDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 446 PM EST WED DEC 25 2013
THURSDAY NIGHT...WITH PASSAGE OF SFC RIDGE...LINGERING LES WILL END
AS WINDS SHIFT SW/OFFSHORE. EXPECT LES WITH THE STRONGER LOW LEVEL CONV
OVER THE FAR NORTHEAST CWA...PER HIGH RES MODELS...COULD STILL
PRODUCE A FEW MORE INCHES OF SNOW. HOWEVER...THE SNOW OVER THE
KEWEENAW SHOULD GENERALLY BE LIGHT...WITH AN INCH OR LESS.
FRIDAY INTO FRI NIGHT...WAA WILL DOMINATE WITH A TEMPORARY
TRANSITION TOWARD A MORE ZONAL PATTERN. THERE MAY BE PERIOD OF LIGHT
PCPN ASSOCIATED WITH ISENTROPIC LIFT THROUGH THE 850-700 MB FRONTAL
ZONE. THE DEEPEST MOISTURE AND BEST CHANCE FOR SATURATION WITH
MEASURABLE PCPN IS EXPECTED FROM THE KEWEENAW INTO THE NE CWA. THERE
MAY BE ENOUGH OF A WARM LAYER...PER NAM/GFS...FOR SOME LIGHT MIXED
PCPN. HOWEVER GIVEN MODEL DIFFERENCES COMAPRED TO THE COLDER
ECMWF...CONFIDENCE WAS NOT HIGH ENOUGH TO INCLUDE ANY SLEET OR FREEZING
RAIN AT THIS TIME.
SAT THROUGH SAT NIGHT...WARMING WILL CONTINUE AHEAD OF A SHRTWV
TRACKING FROM BC NW TO THE NRN PLAINS. MOST LOCATIONS SHOULD CLIMB
TO NEAR 30. HOWEVER...A COLD FRONT DRIFTING SOUTH ACROSS THE CWA MAY
INFLUENCE MAX TEMPS DEPENING ON HOW QUICKLY IT MOVES N-S THROUGH THE
AREA FROM THE LATE MORNING THROUGH THE AFTERNOON. MODEL DIFFERENCES
REMAIN REGARDING THE STRENGTH/TIMING OF THE SHRTWV AND SFC TROUGH
DEVELOPMENT TO THE SOUTH. AFTER THE ARCTIC COLD FRONT MOVES THROUGH
WITH 850 MB TEMPS DROPPING TO AROUND -18C BY 12Z/SUN...LAKE ENHANCED
TO LES WILL DEVELOP. A PERIOD OF MODERATE TO EVEN HEAVY SNOW MAY BE
POSSIBLE FOR NORTH FLOW FAVORED SNOWBELTS IF THE STRONGER
SHRTWV/TROUGH DEVELOPS.
SUN-WED...AFTER WINDS GRADUALLY BACK ON SUN AS HIGH PRES BUILDS
TOWARD THE AREA...PERSISTENT LES WILL THEN DEVELOP FROM SUN THROUGH
TUE...MOSTLY FOR W TO WNW WIND FAVORED SNOWBELTS...AS ACRTIC AIR
SETTLES OVER THE AREA WITH 850 MB TEMPS TO AROUND -25C. BY WED THERE
IS MORE UNCERTAINTY WITH THE WIND DIRECTION GIVEN THE POTENTIAL FOR
CLIPPER SHRTWVS(ECMWF) THAT MAY BRING BACKING WINDS.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z THURSDAY NIGHT)
ISSUED AT 1240 AM EST THU DEC 26 2013
CMX...EXPECT PREDOMINANT MVFR CONDITIONS THROUGH THE PERIOD WITH
LAKE EFFECT SNOW SHOWERS. THERE WILL BE BRIEF TIMES IFR VIS WILL BE
IN THERE...ESPECIALLY THU NIGHT.
IWD...MVFR CONDITIONS WL IMPROVE TO VFR ON THU AFTERNOON WITH THE
APRCH OF A HI PRES RDG/ BACKING LLVL FLOW.
SAW...EXPECT MVFR CIGS TNGT ASSOCIATED WITH A LO PRES TROF PASSAGE.
VFR WX SHOULD THEN FOLLOW THU WITH A DOWNSLOPE W WIND FOLLOWING THE
TROF.
&&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 446 PM EST WED DEC 25 2013
EXPECT W TO NW WINDS UP TO 25 KTS TONIGHT TO DIMINISH TO UNDER 20
KTS ON THU WITH APPROACH OF A HI PRES RIDGE/WEAKER PRES GRADIENT.
FOLLOWING THE PASSAGE OF AN ARCTIC COLD FRONT...NORTH GALES ARE
POSSIBLE SATURDAY NIGHT INTO SUNDAY. HEAVY FREEZING SPRAY IS ALSO
EXPECTED FROM SATURDAY NIGHT INTO TUESDAY. &&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
LAKE EFFECT SNOW ADVISORY UNTIL 7 PM EST THIS EVENING FOR MIZ006-
007.
LAKE EFFECT SNOW WARNING UNTIL 1 PM EST THIS AFTERNOON FOR
MIZ002.
LAKE EFFECT SNOW WARNING UNTIL 7 PM EST THIS EVENING FOR MIZ001-
003.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...KC
LONG TERM...JLB
AVIATION...07
MARINE...KC
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
1156 PM EST WED DEC 25 2013
.SHORT TERM...(THIS EVENING THROUGH THURSDAY)
ISSUED AT 446 PM EST WED DEC 25 2013
12Z RAOBS/LATEST WV IMAGERY AND RUC ANALYSIS SHOW UPR TROF CENTERED
OVER CENTRAL NAMERICA BTWN RDGING OVER THE ERN CONUS EXTENDING INTO
QUEBEC AND A STRONGER MEAN RDG OVER THE W. VERY CHILLY AIR LINGERS
OVER THE UPR LKS WITH H85 TEMPS IN THE -15C TO -20C RANGE. THERE ARE
SEVERAL SHRTWVS OF INTEREST EMBEDDED WITHIN THIS UPR TROF. THE FIRST
IS MOVING INTO WRN UPR MI EARLY THIS AFTN AND ACCOMPANIED BY AN AREA
OF COLDER CLD TOPS SHOWN ON IR STLT IMAGERY. IN CONCERT WITH SOME
DEEPER MSTR TO H5 SHOWN ON THE 12Z INL RAOB...SCT-NMRS -SHSN
IMPACTED MUCH OF THE CWA INTO EARLY THIS AFTN BEFORE LARGER SCALE
FORCING ASSOCIATED WITH THE SHRTWV THAT CAUSED THE SN LAST NGT/THIS
MRNG EXITED THE AREA. BUT LARGER SCALE QVECTOR DVGC HAS WEAKENED
THIS SHRTWV/WARMED CLD TOP TEMPS...DIMINISHING THE SHSN DURING THE
LAST COUPLE OF HRS. IN FACT...THERE HAS BEEN SOME CLRG THIS AFTN. A
SECOND SHRTWV IS DIGGING SSEWD THRU MANITOBA...ACCOMPANIED BY A
120KT H3 JET MAX. YET ANOTHER SHRTWV RIDING OVER THE TOP OF THE WRN
RDG IS PUSHING INTO BRITISH COLUMBIA.
MAIN FCST CONCERNS IN THE SHORT TERM ARE POPS/SN AMNTS/NEED FOR
HEADLINES ASSOCIATED WITH PARADE OF SHRTWS PASSING THRU THE UPR LKS
WITHIN THE PERSISTENT UPR TROF.
TNGT...AS SHRTWV DIGGING SEWD THRU MANITOBA PASSES INTO WI
TNGT...EXPECT A WSHFT TO THE NW TO DRIVE A LO PRES TROF ONSHORE.
ALTHOUGH THE 12Z NAM/GFS SHOW THE SHARPEST DPVA/H7-3 QVECTOR CNVGC
PASSING TO THE SW OF THE CWA CLOSER TO THE ACCOMPANYING H3 JET
CORE...NAM FCST SDNGS SHOW INVRN BASE AT CMX RISING TO NEAR 7K FT
THIS EVNG IN THE PRESENCE OF DEEPER MSTR. WITH VERY COLD LLVL AIR
LINGERING NEAR THE SFC...THE SFC WSHFT FM THE WSW OVER THE INTERIOR
WL NOT BE AS DRAMATIC AS OVER/NEAR LK SUP. THE RESULT WL BE
SHARPENED LAND BREEZE LLVL CNVGC NEAR LK SUP...FIRST OVER THE NW CWA
THIS EVNG AND THEN ALSO OVER THE FAR ERN CWA LATER. SINCE THE
ACCOMPANYING UVV IS CENTERED WITHIN THE DGZ AS SHOWN ON NAM FCST
SDNGS...SN/WATER RATIOS SHOULD BE AS HI AS 25-30:1. RELATIVELY LGT
WINDS NO HIER THAN 10-15 KTS SHOULD RESULT IN MINIMAL FRACTURING OF
THE SN FLAKES. CONSIDERING THE FRBL SN/WATER RATIOS AND POTENTIAL
FOR ENHANCED SN NEAR LAND BREEZE CNVGC ZONES...OPTED TO ISSUE AN LES
ADVY FOR THE KEWEENAW AND ALGER/LUCE COUNTIES FOR MAINLY THE AREAS
NEAR LK SUP E FM GRAND MARAIS TO CRISP POINT. ALSO CONCERNED AT
LEAST NORTHERN ONTONAGON COUNTY COULD SEE SOME HEAVIER SN TNGT...
BUT OPTED NOT TO INCLUDE THAT ZONE IN THE HEADLINE SINCE HEAVIER SN
IS LIKELY TO IMPACT ONLY THE RELATIVELY UNPOPULATED NRN PORTION OF
THIS COUNTY. SINCE THERE HAS BEEN PARTIAL CLRG OVER MUCH OF THE CWA
LATE THIS AFTN...OPTED TO LOWER MIN TEMPS A BIT WITH THE EXPECTATION
TEMPS COULD FALL QUICKLY BEFORE A WSHFT TOWARD THE NW ABV THE
SHALLOW COLD AIR NEAR THE SFC BRINGS IN MORE CLDS. BACKING LLVL FLOW
LATE AHEAD OF APRCHG HI PRES RDG/SHRTWV RDG FOLLOWING THE DEPARTING
DIGGING SHRTWV MAY BRING SOME PARTIAL CLRG/MORE UNMODIFIED ARCTIC
AIR TO THE INTERIOR W NEAR THE WI BORDER AS WELL.
THU...NEXT SHRTWV NOW TOPPING UPR RDG OVER WRN CANADA IS PROGGED TO
DIG SEWD THRU MN IN PERSISTENT NW FLOW ALF...WITH SHARPEST DEEP LYR
QVECTOR CNVGC PASSING TO THE SW OF UPR MI. LLVL WINDS ARE FCST TO
BACK SLOWLY TOWARD THE WSW OVER MAINLY THE WRN CWA THRU THE DAY
AHEAD OF THIS DISTURBANCE...SO LES SHOULD BECOME CONFINED TO MAINLY
THE KEWEENAW. ALTHOUGH SN TOTALS OVER KEWEENAW COUNTY TNGT MAY NOT
BE AS IMPRESSIVE AS IN HOUGHTON COUNTY...THE NRN PORTION OF THE
KEWEENAW WL LIKELY SEE MORE SN ON THU...ESPECIALLY LATER IN THE DAY.
WITH A MORE 300 DEGREE FLOW LINGERING THRU MUCH OF THE DAY TO THE
E...EXPECT THE MOST WDSPRD AND HEAVIER LES TO IMPACT ERN ALGER AND
THE THE N HALF OF LUCE COUNTY. OVER THE SCENTRAL...ARRIVAL OF HI
PRES RDG AHEAD OF THE SHRTWV WL BRING PARTIAL SUNSHINE FILTERED BY
MID/HI CLDS ASSOCIATED WITH THE MSTR STARVED SHRTWV.
.LONG TERM...(THURSDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 446 PM EST WED DEC 25 2013
THURSDAY NIGHT...WITH PASSAGE OF SFC RIDGE...LINGERING LES WILL END
AS WINDS SHIFT SW/OFFSHORE. EXPECT LES WITH THE STRONGER LOW LEVEL CONV
OVER THE FAR NORTHEAST CWA...PER HIGH RES MODELS...COULD STILL
PRODUCE A FEW MORE INCHES OF SNOW. HOWEVER...THE SNOW OVER THE
KEWEENAW SHOULD GENERALLY BE LIGHT...WITH AN INCH OR LESS.
FRIDAY INTO FRI NIGHT...WAA WILL DOMINATE WITH A TEMPORARY
TRANSITION TOWARD A MORE ZONAL PATTERN. THERE MAY BE PERIOD OF LIGHT
PCPN ASSOCIATED WITH ISENTROPIC LIFT THROUGH THE 850-700 MB FRONTAL
ZONE. THE DEEPEST MOISTURE AND BEST CHANCE FOR SATURATION WITH
MEASURABLE PCPN IS EXPECTED FROM THE KEWEENAW INTO THE NE CWA. THERE
MAY BE ENOUGH OF A WARM LAYER...PER NAM/GFS...FOR SOME LIGHT MIXED
PCPN. HOWEVER GIVEN MODEL DIFFERENCES COMAPRED TO THE COLDER
ECMWF...CONFIDENCE WAS NOT HIGH ENOUGH TO INCLUDE ANY SLEET OR FREEZING
RAIN AT THIS TIME.
SAT THROUGH SAT NIGHT...WARMING WILL CONTINUE AHEAD OF A SHRTWV
TRACKING FROM BC NW TO THE NRN PLAINS. MOST LOCATIONS SHOULD CLIMB
TO NEAR 30. HOWEVER...A COLD FRONT DRIFTING SOUTH ACROSS THE CWA MAY
INFLUENCE MAX TEMPS DEPENING ON HOW QUICKLY IT MOVES N-S THROUGH THE
AREA FROM THE LATE MORNING THROUGH THE AFTERNOON. MODEL DIFFERENCES
REMAIN REGARDING THE STRENGTH/TIMING OF THE SHRTWV AND SFC TROUGH
DEVELOPMENT TO THE SOUTH. AFTER THE ARCTIC COLD FRONT MOVES THROUGH
WITH 850 MB TEMPS DROPPING TO AROUND -18C BY 12Z/SUN...LAKE ENHANCED
TO LES WILL DEVELOP. A PERIOD OF MODERATE TO EVEN HEAVY SNOW MAY BE
POSSIBLE FOR NORTH FLOW FAVORED SNOWBELTS IF THE STRONGER
SHRTWV/TROUGH DEVELOPS.
SUN-WED...AFTER WINDS GRADUALLY BACK ON SUN AS HIGH PRES BUILDS
TOWARD THE AREA...PERSISTENT LES WILL THEN DEVELOP FROM SUN THROUGH
TUE...MOSTLY FOR W TO WNW WIND FAVORED SNOWBELTS...AS ACRTIC AIR
SETTLES OVER THE AREA WITH 850 MB TEMPS TO AROUND -25C. BY WED THERE
IS MORE UNCERTAINTY WITH THE WIND DIRECTION GIVEN THE POTENTIAL FOR
CLIPPER SHRTWVS(ECMWF) THAT MAY BRING BACKING WINDS.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z THURSDAY NIGHT)
ISSUED AT 1155 PM EST WED DEC 25 2013
CMX...EXPECT PREDOMINANT MVFR CONDITIONS THROUGH THE PERIOD WITH
LAKE EFFECT SNOW SHOWERS. THERE WILL BE BRIEF TIMES IFR VIS WILL BE
IN THERE...ESPECIALLY THU NIGHT.
IWD...MVFR CONDITIONS WL IMPROVE TO VFR ON THU AFTERNOON WITH THE
APRCH OF A HI PRES RDG/ BACKING LLVL FLOW.
SAW...EXPECT MVFR CIGS TNGT ASSOCIATED WITH A LO PRES TROF PASSAGE.
VFR WX SHOULD THEN FOLLOW THU WITH A DOWNSLOPE W WIND FOLLOWING THE
TROF.
&&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 446 PM EST WED DEC 25 2013
EXPECT W TO NW WINDS UP TO 25 KTS TONIGHT TO DIMINISH TO UNDER 20
KTS ON THU WITH APPROACH OF A HI PRES RIDGE/WEAKER PRES GRADIENT.
FOLLOWING THE PASSAGE OF AN ARCTIC COLD FRONT...NORTH GALES ARE
POSSIBLE. HEAVY FREEZING SPRAY IS ALSO EXPECTED FROM SATURDAY NIGHT
INTO TUESDAY.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
LAKE EFFECT SNOW ADVISORY UNTIL 7 PM EST THURSDAY FOR MIZ006-007.
LAKE EFFECT SNOW WARNING UNTIL 1 PM EST THURSDAY FOR MIZ002.
LAKE EFFECT SNOW WARNING UNTIL 7 PM EST THURSDAY FOR MIZ001-003.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...KC
LONG TERM...JLB
AVIATION...07
MARINE...KC
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
352 AM CST THU DEC 26 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 348 AM CST THU DEC 26 2013
WE CONTINUE TO FIND OURSELVES WITHIN MOIST CYCLONIC NORTHWEST FLOW
THIS MORNING...WITH CLOUDS AND BOUTS OF FLURRIES/LIGHT SNOW
CONTINUING TO DOMINATE THE NRN PLAINS AND UPPER MS VALLEY. THE TWO
FEATURES OF INTEREST THIS MORNING ARE THE STRONG UPPER WAVE
CURRENTLY VISIBLE IN WATER VAPOR IMAGERY MOVING ACROSS THE DAKOTAS
AND A WARM/STATIONARY FRONT THAT IS MORE OR LESS LINED UP WITH THE
MN RIVER FROM WC INTO SE MN. CURRENT THINKING IS THAT THIS FRONT
WILL ACT AS A FOCUS FOR A HEAVIER BAND OF PRECIP FROM ABOUT 15Z-21Z
TODAY. BASED POP/QPF GRIDS FOR THIS BAND OF SNOW ON THE GFS AND
SREF...WHICH RESULTED IN THE BAND COMING DOWN BETWEEN I-94 AND THE
MN RIVER. THOUGH CATEGORICAL POPS HAVE BEEN RETAINED...THE HRRR AND
HOPWRF MEMBERS ALONG THE THE NAM/GEM SHOW VERY LITTLE SNOW COMING
DOWN ALONG THIS FRONT...INSTEAD TAKING MOST OF IT ACROSS NRN MN WITH
THE BRUNT OF THE FORCING WITH THE UPPER WAVE...SO WOULD NOT BE
SURPRISED IF THESE POPS END UP BEING OVERDONE. THIS LOOKS TO BE A
FAIRLY TRANSIENT FEATURE WHICH MEANS IT IS ONLY EXPECTED TO BRING A
DUSTING TO ONE INCH OF SNOW. FOR THIS AFTERNOON INTO TONIGHT...WE
FINALLY GET ON THE BACKSIDE OF ALL OF THE PASSING SHORTWAVES IN NW
FLOW...WHICH MEANS WE WILL FINALLY SHUT OFF THE SNOW MACHINES AND
WORK A CLEARING OF THE LOW CLOUDS AT LEAST FROM WEST TO EAST.
FOR TEMPERATURES...BASED ON THE WARMER TEMPERATES SEEN
YESTERDAY...FAVORED HIGHS TODAY TOWARD THE HIGHER END OF
GUIDANCE...ESPECIALLY SOUTH OF THE BOUNDARY. FOR TONIGHT...WINDS
WILL START TO INCREASE OUT OF THE SW AND WILL START TO ADVECT IN A
MILDER PACIFIC AIRMASS. THE WAA WILL BE TEMPERED A BIT BY AT LEAST A
PARTIAL CLEARING OF THE SKIES AND ATTENDANT RADIATIONAL
COOLING...BUT LOOKS TO BE ENOUGH TO SAFELY KEEP EVERYONE ABOVE ZERO
FOR A SECOND NIGHT IN A ROW.
.LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 348 AM CST THU DEC 26 2013
LONG TERM TRENDS CONTINUE TO REMAIN ON TRACK AT LEAST EARLY IN THE
PERIOD. STILL SEE THE POTENTIAL OF AT LEAST GROUND BLIZZARD
CONDITIONS DEVELOPING BY SATURDAY NIGHT ACROSS MUCH OF WESTERN
INTO SOUTHERN MINNESOTA. STILL RATHER MILD BEFORE THEN.
SHOULD SEE SOME HIGH TEMPERATURES WARMING TO AROUND 40 OR SO IN
SOUTHWEST MINNESOTA ON FRIDAY. VERY MILD PACIFIC AIR RIDES EAST
INTO THE AREA FRIDAY...WITH 85H TEMPERATURES WARMING TO 8-10C BY
FRIDAY EVENING OVER THE SOUTHWEST. MINIMAL MIX WITH THIS SHOULD
YIELD THE WARMER TEMPERATURES...WITH LOWER AND SOME MIDDLE 30S TO
THE EAST. SHOULD REMAIN RATHER WARM FRIDAY NIGHT AHEAD OF THE
ARCTIC FRONT. LOWS WILL BE DETERMINED BY WINDS OVERNIGHT. ANY
DECOUPLING OF THE BL WILL STILL GENERATE SOME COOL READINGS.
OVERALL...MODELS HAVE TRENDED A LITTLE WETTER WITH THE TROUGH ASSOCIATED
WITH THE ARCTIC COLD FRONT THAT WILL DIVE SOUTH OVER THE AREA
SATURDAY NIGHT. IT DOES APPEAR THERE WILL BE THE POTENTIAL OF AT
LEAST A PERIOD OF SNOW ASSOCIATED WITH THIS FEATURE AS IT MOVES
THROUGH. DID USE POTWX AND INTRODUCED SOME FREEZING DRIZZLE AT
LEAST INTIALLY AS THE FRONT ARRIVES. THIS...ALONG WITH SOME OF
THE MORE MILD TEMPERATURES MAY PROHIBIT SIGNIFICANT BLOWING SNOW
DEVELOPMENT FOR A TIME...BUT BELIEVE ANY POTENTIAL CRUST ON THE
SNOW WILL BE ERODED BY THE STRONG WINDS DEVELOPING AS THE COLD AIR
ARRIVES. BUFKIT PROFILES STILL INDICATE WIND GUSTS AROUND 35 KTS PLUS
LIKELY SATURDAY NIGHT...ESPECIALLY ALONG AND SOUTH OF THE
MINNESOTA RIVER VALLEY. THIS SHOULD BE ENOUGH TO GENERATE THE MORE
WIDESPREAD BLOWING SNOW CONDITIONS. WILL HAVE TO MONITOR THIS
TREND WITH HEADLINES A DEFINITE POSSIBILITY.
VERY COLD CONDITIONS ENSUE FOR MONDAY AND TUESDAY. MONDAY MORNING
APPEARS TO BE LIKELY THE COLDEST FOR THE CWA...WITH TUESDAY
MORNING A GOOD SECOND...ESPECIALLY TO THE EAST. MUCH OF THE AREA
MAY STAY BELOW ZERO ON MONDAY. SURFACE WINDS SHOULD BE
LIGHT...BUT MAY STILL PRODUCE WIND CHILLS CLOSE TO WARNING
CRITERIA OVER THE NORTHERN CWA SUNDAY NIGHT/MONDAY MORNING. TIMING
OF ANY ADDITIONAL SNOW EVENTS DIFFICULT...ALTHOUGH THE GFS AND GEM
CONTINUE TO TRACK A SHOT OF LIGHT SNOW OVER SOUTHERN MINNESOTA
MONDAY NIGHT INTO EARLY TUESDAY. HAVE ENTERED A CHANCE FOR SNOW
WITH THIS FOR NOW. SOME MINOR TEMPERATURE MODERATION LATER IN THE
PERIOD COULD YIELD MORE LIGHT SNOW...BUT DIFFICULT TO LATCH ONTO
ANYTHING SIGNIFICANT AT THIS TIME.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z THURSDAY NIGHT)
ISSUED AT 1050 PM CST WED DEC 25 2013
A 2000-3000FT DECK WILL CONTINUE TO EXPAND EAST/SOUTHEAST ACROSS
THE TAF AREA OVERNIGHT. EXPECT A FEW ATTENDANT LIGHT SNOW SHOWERS
AND/OR FLURRIES...BUT THE MAIN BAND OF VSBY-REDUCING SNOW WILL
MOVE ACROSS THE AREA AFTER DAYBREAK THURSDAY. THE PRIMARY WINDOW
FOR 1-3SM VSBY REDUCTIONS AND SNOW WILL PRIMARILY EXIST BETWEEN
13Z AND 21Z. AFTER THE SNOW ENDS...A SCT-BKN MVFR DECK WILL LINGER
THROUGH 00Z FRIDAY...WITH SCATTERING EXPECTED FROM WEST TO EAST ON
THURSDAY NIGHT. LIGHT/VARIABLE TO SOUTHEAST WINDS AT 5-8KTS
EXPECTED FOR THURSDAY.
KMSP...
MVFR DECK WILL PREVAIL OVERNIGHT...WITH FLURRIES AND/OR VERY LIGHT
SNOW POSSIBLE. A MORE ORGANIZED AREA OF SNOW WILL ARRIVE AROUND
16Z...WITH 1-3SM VSBYS EXPECTED THROUGH 21Z...WITH TOTAL ACCUM
AROUND OR JUST ABOVE ONE INCH EXPECTED. MVFR LEVEL CLOUDS LINGER
THURSDAY AFTERNOON...WITH BREAKS MORE COMMON AFTER 00Z FRIDAY.
/OUTLOOK FOR KMSP/
FRI...VFR. WINDS SW 5-10 KTS.
SAT...VFR. CHC MVFR/-SN LATE. WINDS SW 5-10 KTS BCMG NW 20G30KTS.
SUN...VFR. WINDS NW 10 KTS.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
&&
$$
SHORT TERM...MPG
LONG TERM...DWE
AVIATION...LS
AREA FORECAST DISCUSSION
NWS GREENVILLE-SPARTANBURG SC
403 AM EST THU DEC 26 2013
.SYNOPSIS...
SHALLOW MOISTURE FROM THE GULF OF MEXICO WILL BRUSH THE SOUTHEAST
PIEDMONT TODAY. DRY HIGH PRESSURE WILL THEN BUILD OVER THE REGION
THROUGH FRIDAY NIGHT. EXPECT LOW PRESSURE TO TRACK FROM THE GULF OF
MEXICO SATURDAY TO THE CAROLINAS SUNDAY. A COLD FRONT WILL CROSS ON
MONDAY BRINGING COOLER WEATHER FOR TUESDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 400 AM EST THURSDAY...PATCHY RAIN AND EVEN A COUPLE HEAVIER
SHOWERS CONTINUE TO AFFECT THE NE PIEDMONT OF SC AND THE SRN NC
PIEDMONT THIS MORNING. A FEW AREAS OF FREEZING RAIN ARE STILL
POSSIBLE TO THE NORTH AND WEST OF CHARLOTTE. WE HAVE ISSUED A
SPECIAL WEATHER STATEMENT TO ACCOUNT FOR THIS. FORTUNATELY...THE
HEAVIER SHOWERS LOOK TO BE DEVELOPING FATHER TO THE SOUTH...AND THEY
SHOULD MAINLY AFFECT UNION...YORK AND CHESTER COUNTIES WHERE
TEMPERATURES ARE ABOVE FREEZING. HIGH CLOUDS WILL ALSO COVER THE SRN
ZONES FOR A FEW MORE HOURS...KEEPING SKIES MOSTLY CLOUDY EVEN WHERE
THE LOW CLOUDS HAVE MOVED OUT.
AS OF 110 AM EST THURSDAY...WEAK RADAR RETURNS ARE SHOWING UP OVER
THE SOUTHEAST TIER OF COUNTIES. A COUPLE AWOS SITES DOWN IN CAE/S
AREA HAVE REPORTED PCPN OVER THE PAST HOUR...SO THE PCPN DOES APPEAR
TO BE REACHING THE GROUND. THE THINKING IS THAT THE PCPN WON/T MAKE
MUCH MORE PROGRESS TO THE NORTHWEST...BUT THAT IT WILL EXPAND INTO
THE SRN NC PIEDMONT. THIS IS WHAT OUR WORKSTATION WRF MODEL IS
SHOWING. SO FAR TEMPERATURES HAVE SHOWN A TENDENCY TO WARM AS CLOUD
COVER AND LIGHT PCPN HAS MOVED IN RIGHT. RIGHT NOW NO PCPN IS
FALLING WHERE THE TEMPERATURE IS AT OR BELOW FREEZING. FOR THE MOST
PART I THINK THAT WILL BE THE TREND OVER THE NEXT SEVERAL HOURS.
STILL...THERE COULD BE ONE OR TWO PATCHES OF BRIEF FREEZING RAIN
ACROSS THE I-77 CORRIDOR. FOR NOW I JUST HAVE A TINY AMOUNT OF
FREEZING RAIN IN THIS AREA IN THE GRIDS...CERTAINLY NOT ENOUGH TO
GET EXCITED ABOUT. BUT WE WILL WATCH THIS CLOSELY AS IT WILL ONLY
TAKE A LIGHT GLAZE TO MAKE BRIDGES AND ELEVATED SFC/S ICY
CONSIDERING HOW COOL IT/S BEEN THE PAST COUPLE DAYS.
SKIES SHOULD CLEAR BY MID-MORNING...FOLLOWED BY A CLEAR AND
SEASONABLY COOL DAY. HIGH PRESSURE WILL BRING CLEAR AND COOL
CONDITIONS TONIGHT.
&&
.SHORT TERM /FRIDAY THROUGH SUNDAY/...
AT 230 AM EST THURSDAY...ON FRIDAY MORNING A POSITIVELY TILTED UPPER
TROUGH WILL EXTEND FROM HUDSON BAY TO NORTHERN MEXICO. THE NORTHERN
AND SOUTHERN PORTIONS OF THE TROUGH GO OUT OF PHASE BY SATURDAY
MORNING...WITH THE NORTHERN TROUGH DEAMPLIFYING OVER CANADA...AND AN
UPPER LOW CLOSES OFF OVER TX OR OK. THE UPPER LOW FILLS AND
PROGRESSES ON SATURDAY...WHILE A SOUTHERN STREAM RIDGE DOWNSTREAM
AMPLIFIES OVER THE SOUTHEAST. THE SHORTWAVE REMAINS OF THE LOW THEN
CROSS THE SOUTHERN APPALACHIANS ON SUNDAY.
HIGH PRESSURE WILL REMAIN OVER CAROLINAS AND GA FROM FRIDAY THROUGH
SATURDAY...WHILE A STATIONARY FRONT LINGER ACROSS S FL AND THE
SOUTHERN GULF OF MEXICO. INITIALLY...CIRRUS SPILLING EAST OVER THE
UPPER RIDGE WILL BE THE ONLY CLOUD COVER. ON SATURDAY...THE GULF
FRONT WILL LIFT NORTH...AND ISENTROPIC UPGLIDE WILL SET UP OVER THE
BOUNDARY. LOW CLOUDS AND PRECIPITATION SHOULD CROSS THE UPPER
SAVANNAH RIVER VALLEY ON SATURDAY AFTERNOON...SPREADING ACROSS THE
ENTIRE AREA ON SATURDAY EVENING. THERMAL PROFILES AND THICKNESS
VALUES SOLIDLY SUPPORT LIQUID PRECIPITATION SATURDAY NIGHT AND
SUNDAY MORNING...ALTHOUGH SOME MOUNTAIN SURFACE TEMPERATURES COULD
BE JUST A FEW DEGREES ABOVE FREEZING BY SUNDAY MORNING.
WITH THE WARM FRONT NEVER REACHING THIS FAR NORTH...LOW LEVEL FLOW
IS EXPECTED TO BACK FROM SOUTHEASTERLY TO NORTHEASTERLY AS IN SITU
COLD AIR DAMMING SETS UP...SHIFTING THE BETTER UPSLOPE FLOW
COMPONENT FROM THE SOUTH FACING BLUE RIDGE TO THE EAST FACING BLUE
RIDGE.
A SURFACE WAVE WILL DRAG A COLD FRONT ACROSS THE AREA AROUND MIDDAY
SUNDAY...FOLLOWED BY DRYING IN THE LEE OF THE MOUNTAINS. MOIST NW
FLOW INTO THE NC MOUNTAINS BORDERING TN WILL KEEP PRECIPITATION
GOING THROUGH LATE AFTERNOON THERE. A LACK OF ICE NUCLEATION SUNDAY
AFTERNOON WILL NOT SUPPORT A CHANGE OVER TO SNOW SHOWERS AT
HIGH ELEVATIONS.
TEMPERATURES WILL EXHIBIT A DECREASING DIURNAL TEMPERATURE RANGE AS
CLOUD COVER AND MOISTURE INCREASE...LIMITING COOLING AND HEATING.
&&
.LONG TERM /SUNDAY NIGHT THROUGH WEDNESDAY/...
AS OF 210 AM THURSDAY...LOW PRESSURE MOVES OFF THE MID ATLANTIC
COAST SUNDAY NIGHT AS A COLD FRONT MOVES OVER WESTERN TENNESSEE AND
PROGRESSES EAST ON MONDAY. UPSLOPE FLOW UP AGAINST THE TN AND NC
BORDER WILL LIKELY NOT PRODUCE MUCH IN THE WAY OF SHOWERS AS
MOISTURE IS LIMITED. THERE ARE DIFFERENCES IN THE TIMING AND AMOUNT
OF MTN SNOW SHOWERS FROM LATE SUNDAY NIGHT TO MONDAY NIGHT BETWEEN
THE GFS AND ECMWF. GFS HAS VERY BRIEF WRAP AROUND MOISTURE EARLY
SUNDAY NIGHT FOR THE NC MTNS ALONG THE TN BORDER THEN BRING FRONTAL
MOISTURE UP AGAINST THE MTNS LATE MONDAY AND MONDAY NIGHT. THE ECMWF
HAS MORE SIGNIFICANT WRAP AROUND MOISTURE EARLY SUNDAY NIGHT AND
GRADUALLY DECREASES THAT TIL DISSIPATED EARLY MONDAY...THEN NOTHING
THROUGH MID WEEK. COMPROMISED AND ALSO MAINTAINS SOME OF PREVIOUS
FORECAST THINKING AS THIS COULD CHANGE AGAIN WITH THE NEXT MODEL
RUN. BEHIND THE COLD FRONT THE GFS A MUCH DEEPER THICKNESS TROUGH
COMPARED TO THE ECMWF.
WEATHER BECOMES DRIER AND A BIT COOLER TUESDAY UNDER THE THICKNESS
TROUGH PASSING WEST TO EAST. WEAK SURFACE HIGH PRESSURE WILL REMAIN
OVER THE WESTERN CAROLINAS TUESDAY AND WEDNESDAY. EXPECT SOME FORM
OF A NEW LOW PRESSURE DEVELOPING NEAR TEXAS LATE WEDNESDAY AND
WEDNESDAY NIGHT...THEN MOVING TOWARD OUR REGION. CLOUDS WILL
INCREASE WEDNESDAY NIGHT BUT ALL PRECIP WILL ARRIVE AFTER OUR
CURRENT DAY 7.
TEMPERATURES WILL BE A LITTLE BELOW NORMAL THROUGH THE PERIOD WITH
THE COOLEST DAY ON TUESDAY.
&&
.AVIATION /09Z THURSDAY THROUGH MONDAY/...
AT KCLT...THE LATEST NAM SOUNDINGS ARE MUCH DRIER AT THE AIRFIELD.
IN FACT...THEY ARE TOO DRY BASED ON THE CLOUD DECK WHICH HAS
RECENTLY MOVED IN. THE RAP SOUNDINGS ARE DOING A BETTER JOB...BUT
EVEN THEN THE MOISTURE IS QUITE SHALLOW. SOME WEAK RADAR RETURNS ARE
SHOWING UP NOW ABOUT 30 NM SOUTH OF THE AIRFIELD. BUT THE AIRMASS
DRIES OUT QUICKLY THE FARTHER NORTH ONE GOES. I THINK ANY PCPN WILL
MISS THE AIRFIELD TO THE SOUTH...BUT I DID ADD A VCSH. THERE IS
STILL A SMALL CHANCE OF A BRIEF PERIOD OF FREEZING RAIN...THOUGH I
SUSPECT THE SFC TEMPERATURES WILL STAY A COUPLE DEGREES ABOVE
FREEZING UNDER THE CLOUD DECK. AS FOR CIG HEIGHTS...THEY SHOULD FALL
TO AROUND 4KFT IN A COUPLE HOURS...THEN CLEAR BY 12-13 UTC. LIGHT
WINDS WILL TURN OUT OF THE NORTH AROUND NOON AS A WEAK COLD FRONT
CROSSES THE REGION.
ELSEWHERE...VFR CIGS WILL CONTINUE OVER THE UPSTATE FOR SEVERAL MORE
HOURS. ANY PCPN SHOULD STAY SOUTHEAST OF THE UPSTATE AIRFIELDS. NOT
EXPECTING THE LOWER VFR CIGS TO MAKE IT INTO KHKY OR KAVL. THE CIGS
WILL CLEAR FROM WEST TO EAST BETWEEN 10-12 UTC. WINDS WILL BE
LIGHT...BUT WILL TURN OUT OF THE NORTH LATER TODAY AS A WEAK COLD
FRONT CROSSES THE REGION.
OUTLOOK...VFR CONDITIONS ARE EXPECTED TO PERSIST THROUGH THE WEEK.
LOW PRESSURE WILL DEVELOP OVER THE NORTHERN GULF ON SATURDAY...
CROSSING THE WESTERN CAROLINAS ON SUNDAY. THIS WILL SPREAD RAIN AND
RESTRICTIVE CIGS AND VSBYS ACROSS THE REGION SATURDAY NIGHT AND
SUNDAY.
CONFIDENCE TABLE...
09-15Z 15-21Z 21-03Z 03-09Z
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% HIGH 100%
KHKY HIGH 100% HIGH 100% HIGH 100% HIGH 100%
KGMU HIGH 100% HIGH 100% HIGH 100% HIGH 100%
KAND MED 79% 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...MCAVOY
SHORT TERM...JAT
LONG TERM...DEO
AVIATION...MCAVOY
AREA FORECAST DISCUSSION
NWS GREENVILLE-SPARTANBURG SC
256 AM EST THU DEC 26 2013
.SYNOPSIS...
SHALLOW MOISTURE FROM THE GULF OF MEXICO WILL BRUSH THE SOUTHEAST
PIEDMONT TODAY. DRY HIGH PRESSURE WILL THEN BUILD OVER THE REGION
THROUGH FRIDAY NIGHT. EXPECT LOW PRESSURE TO TRACK FROM THE GULF OF
MEXICO SATURDAY TO THE CAROLINAS SUNDAY. A COLD FRONT WILL CROSS ON
MONDAY BRINGING COOLER WEATHER FOR TUESDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 110 AM EST THURSDAY...WEAK RADAR RETURNS ARE SHOWING UP OVER
THE SOUTHEAST TIER OF COUNTIES. A COUPLE AWOS SITES DOWN IN CAE/S
AREA HAVE REPORTED PCPN OVER THE PAST HOUR...SO THE PCPN DOES APPEAR
TO BE REACHING THE GROUND. THE THINKING IS THAT THE PCPN WON/T MAKE
MUCH MORE PROGRESS TO THE NORTHWEST...BUT THAT IT WILL EXPAND INTO
THE SRN NC PIEDMONT. THIS IS WHAT OUR WORKSTATION WRF MODEL IS
SHOWING. SO FAR TEMPERATURES HAVE SHOWN A TENDENCY TO WARM AS CLOUD
COVER AND LIGHT PCPN HAS MOVED IN RIGHT. RIGHT NOW NO PCPN IS
FALLING WHERE THE TEMPERATURE IS AT OR BELOW FREEZING. FOR THE MOST
PART I THINK THAT WILL BE THE TREND OVER THE NEXT SEVERAL HOURS.
STILL...THERE COULD BE ONE OR TWO PATCHES OF BRIEF FREEZING RAIN
ACROSS THE I-77 CORRIDOR. FOR NOW I JUST HAVE A TINY AMOUNT OF
FREEZING RAIN IN THIS AREA IN THE GRIDS...CERTAINLY NOT ENOUGH TO
GET EXCITED ABOUT. BUT WE WILL WATCH THIS CLOSELY AS IT WILL ONLY
TAKE A LIGHT GLAZE TO MAKE BRIDGES AND ELEVATED SFC/S ICY
CONSIDERING HOW COOL IT/S BEEN THE PAST COUPLE DAYS.
SKIES SHOULD CLEAR BY MID-MORNING...FOLLOWED BY A CLEAR AND
SEASONABLY COOL DAY. HIGH PRESSURE WILL BRING CLEAR AND COOL
CONDITIONS TONIGHT.
&&
.SHORT TERM /FRIDAY THROUGH SUNDAY/...
AT 230 AM EST THURSDAY...ON FRIDAY MORNING A POSITIVELY TILTED UPPER
TROUGH WILL EXTEND FROM HUDSON BAY TO NORTHERN MEXICO. THE NORTHERN
AND SOUTHERN PORTIONS OF THE TROUGH GO OUT OF PHASE BY SATURDAY
MORNING...WITH THE NORTHERN TROUGH DEAMPLIFYING OVER CANADA...AND AN
UPPER LOW CLOSES OFF OVER TX OR OK. THE UPPER LOW FILLS AND
PROGRESSES ON SATURDAY...WHILE A SOUTHERN STREAM RIDGE DOWNSTREAM
AMPLIFIES OVER THE SOUTHEAST. THE SHORTWAVE REMAINS OF THE LOW THEN
CROSS THE SOUTHERN APPALACHIANS ON SUNDAY.
HIGH PRESSURE WILL REMAIN OVER CAROLINAS AND GA FROM FRIDAY THROUGH
SATURDAY...WHILE A STATIONARY FRONT LINGER ACROSS S FL AND THE
SOUTHERN GULF OF MEXICO. INITIALLY...CIRRUS SPILLING EAST OVER THE
UPPER RIDGE WILL BE THE ONLY CLOUD COVER. ON SATURDAY...THE GULF
FRONT WILL LIFT NORTH...AND ISENTROPIC UPGLIDE WILL SET UP OVER THE
BOUNDARY. LOW CLOUDS AND PRECIPITATION SHOULD CROSS THE UPPER
SAVANNAH RIVER VALLEY ON SATURDAY AFTERNOON...SPREADING ACROSS THE
ENTIRE AREA ON SATURDAY EVENING. THERMAL PROFILES AND THICKNESS
VALUES SOLIDLY SUPPORT LIQUID PRECIPITATION SATURDAY NIGHT AND
SUNDAY MORNING...ALTHOUGH SOME MOUNTAIN SURFACE TEMPERATURES COULD
BE JUST A FEW DEGREES ABOVE FREEZING BY SUNDAY MORNING.
WITH THE WARM FRONT NEVER REACHING THIS FAR NORTH...LOW LEVEL FLOW
IS EXPECTED TO BACK FROM SOUTHEASTERLY TO NORTHEASTERLY AS IN SITU
COLD AIR DAMMING SETS UP...SHIFTING THE BETTER UPSLOPE FLOW
COMPONENT FROM THE SOUTH FACING BLUE RIDGE TO THE EAST FACING BLUE
RIDGE.
A SURFACE WAVE WILL DRAG A COLD FRONT ACROSS THE AREA AROUND MIDDAY
SUNDAY...FOLLOWED BY DRYING IN THE LEE OF THE MOUNTAINS. MOIST NW
FLOW INTO THE NC MOUNTAINS BORDERING TN WILL KEEP PRECIPITATION
GOING THROUGH LATE AFTERNOON THERE. A LACK OF ICE NUCLEATION SUNDAY
AFTERNOON WILL NOT SUPPORT A CHANGE OVER TO SNOW SHOWERS AT
HIGH ELEVATIONS.
TEMPERATURES WILL EXHIBIT A DECREASING DIURNAL TEMPERATURE RANGE AS
CLOUD COVER AND MOISTURE INCREASE...LIMITING COOLING AND HEATING.
&&
.LONG TERM /SUNDAY NIGHT THROUGH WEDNESDAY/...
AS OF 210 AM THURSDAY...LOW PRESSURE MOVES OFF THE MID ATLANTIC
COAST SUNDAY NIGHT AS A COLD FRONT MOVES OVER WESTERN TENNESSEE AND
PROGRESSES EAST ON MONDAY. UPSLOPE FLOW UP AGAINST THE TN AND NC
BORDER WILL LIKELY NOT PRODUCE MUCH IN THE WAY OF SHOWERS AS
MOISTURE IS LIMITED. THERE ARE DIFFERENCES IN THE TIMING AND AMOUNT
OF MTN SNOW SHOWERS FROM LATE SUNDAY NIGHT TO MONDAY NIGHT BETWEEN
THE GFS AND ECMWF. GFS HAS VERY BRIEF WRAP AROUND MOISTURE EARLY
SUNDAY NIGHT FOR THE NC MTNS ALONG THE TN BORDER THEN BRING FRONTAL
MOISTURE UP AGAINST THE MTNS LATE MONDAY AND MONDAY NIGHT. THE ECMWF
HAS MORE SIGNIFICANT WRAP AROUND MOISTURE EARLY SUNDAY NIGHT AND
GRADUALLY DECREASES THAT TIL DISSIPATED EARLY MONDAY...THEN NOTHING
THROUGH MID WEEK. COMPROMISED AND ALSO MAINTAINS SOME OF PREVIOUS
FORECAST THINKING AS THIS COULD CHANGE AGAIN WITH THE NEXT MODEL
RUN. BEHIND THE COLD FRONT THE GFS A MUCH DEEPER THICKNESS TROUGH
COMPARED TO THE ECMWF.
WEATHER BECOMES DRIER AND A BIT COOLER TUESDAY UNDER THE THICKNESS
TROUGH PASSING WEST TO EAST. WEAK SURFACE HIGH PRESSURE WILL REMAIN
OVER THE WESTERN CAROLINAS TUESDAY AND WEDNESDAY. EXPECT SOME FORM
OF A NEW LOW PRESSURE DEVELOPING NEAR TEXAS LATE WEDNESDAY AND
WEDNESDAY NIGHT...THEN MOVING TOWARD OUR REGION. CLOUDS WILL
INCREASE WEDNESDAY NIGHT BUT ALL PRECIP WILL ARRIVE AFTER OUR
CURRENT DAY 7.
TEMPERATURES WILL BE A LITTLE BELOW NORMAL THROUGH THE PERIOD WITH
THE COOLEST DAY ON TUESDAY.
&&
.AVIATION /08Z THURSDAY THROUGH MONDAY/...
AT KCLT...THE LATEST NAM SOUNDINGS ARE MUCH DRIER AT THE AIRFIELD.
IN FACT...THEY ARE TOO DRY BASED ON THE CLOUD DECK WHICH HAS
RECENTLY MOVED IN. THE RAP SOUNDINGS ARE DOING A BETTER JOB...BUT
EVEN THEN THE MOISTURE IS QUITE SHALLOW. SOME WEAK RADAR RETURNS ARE
SHOWING UP NOW ABOUT 30 NM SOUTH OF THE AIRFIELD. BUT THE AIRMASS
DRIES OUT QUICKLY THE FARTHER NORTH ONE GOES. I THINK ANY PCPN WILL
MISS THE AIRFIELD TO THE SOUTH...BUT I DID ADD A VCSH. THERE IS
STILL A SMALL CHANCE OF A BRIEF PERIOD OF FREEZING RAIN...THOUGH I
SUSPECT THE SFC TEMPERATURES WILL STAY A COUPLE DEGREES ABOVE
FREEZING UNDER THE CLOUD DECK. AS FOR CIG HEIGHTS...THEY SHOULD FALL
TO AROUND 4KFT IN A COUPLE HOURS...THEN CLEAR BY 12-13 UTC. LIGHT
WINDS WILL TURN OUT OF THE NORTH AROUND NOON AS A WEAK COLD FRONT
CROSSES THE REGION.
ELSEWHERE...VFR CIGS WILL CONTINUE OVER THE UPSTATE FOR SEVERAL MORE
HOURS. ANY PCPN SHOULD STAY SOUTHEAST OF THE UPSTATE AIRFIELDS. NOT
EXPECTING THE LOWER VFR CIGS TO MAKE IT INTO KHKY OR KAVL. THE CIGS
WILL CLEAR FROM WEST TO EAST BETWEEN 10-12 UTC. WINDS WILL BE
LIGHT...BUT WILL TURN OUT OF THE NORTH LATER TODAY AS A WEAK COLD
FRONT CROSSES THE REGION.
OUTLOOK...VFR CONDITIONS ARE EXPECTED TO PERSIST THROUGH THE WEEK.
LOW PRESSURE WILL DEVELOP OVER THE NORTHERN GULF ON SATURDAY...
CROSSING THE WESTERN CAROLINAS ON SUNDAY. THIS WILL SPREAD RAIN AND
RESTRICTIVE CIGS AND VSBYS ACROSS THE REGION SATURDAY NIGHT AND
SUNDAY.
CONFIDENCE TABLE...
08-14Z 14-20Z 20-02Z 02-08Z
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% HIGH 100%
KHKY HIGH 100% HIGH 100% HIGH 100% HIGH 100%
KGMU HIGH 100% HIGH 100% HIGH 100% HIGH 100%
KAND MED 71% 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...MCAVOY
SHORT TERM...JAT
LONG TERM...DEO
AVIATION...MCAVOY
AREA FORECAST DISCUSSION
NWS GREENVILLE-SPARTANBURG SC
111 AM EST THU DEC 26 2013
.SYNOPSIS...
SHALLOW MOISTURE FROM THE GULF OF MEXICO WILL BRUSH THE SOUTHEAST
PIEDMONT TODAY. DRY HIGH PRESSURE WILL THEN BUILD OVER THE REGION
THROUGH FRIDAY NIGHT. EXPECT LOW PRESSURE TO TRACK FROM THE GULF OF
MEXICO SATURDAY TO THE CAROLINAS SUNDAY. A COLD FRONT WILL CROSS ON
MONDAY BRINGING COOLER WEATHER FOR TUESDAY.
&&
.NEAR TERM /THROUGH TODAY/...
AS OF 110 AM EST THURSDAY...WEAK RADAR RETURNS ARE SHOWING UP OVER
THE SOUTHEAST TIER OF COUNTIES. A COUPLE AWOS SITES DOWN IN CAE/S
AREA HAVE REPORTED PCPN OVER THE PAST HOUR...SO THE PCPN DOES APPEAR
TO BE REACHING THE GROUND. THE THINKING IS THAT THE PCPN WON/T MAKE
MUCH MORE PROGRESS TO THE NORTHWEST...BUT THAT IT WILL EXPAND INTO
THE SRN NC PIEDMONT. THIS IS WHAT OUR WORKSTATION WRF MODEL IS
SHOWING. SO FAR TEMPERATURES HAVE SHOWN A TENDENCY TO WARM AS CLOUD
COVER AND LIGHT PCPN HAS MOVED IN RIGHT. RIGHT NOW NO PCPN IS
FALLING WHERE THE TEMPERATURE IS AT OR BELOW FREEZING. FOR THE MOST
PART I THINK THAT WILL BE THE TREND OVER THE NEXT SEVERAL HOURS.
STILL...THERE COULD BE ONE OR TWO PATCHES OF BRIEF FREEZING RAIN
ACROSS THE I-77 CORRIDOR. FOR NOW I JUST HAVE A TINY AMOUNT OF
FREEZING RAIN IN THIS AREA IN THE GRIDS...CERTAINLY NOT ENOUGH TO
GET EXCITED ABOUT. BUT WE WILL WATCH THIS CLOSELY AS IT WILL ONLY
TAKE A LIGHT GLAZE TO MAKE BRIDGES AND ELEVATED SFC/S ICY
CONSIDERING HOW COOL IT/S BEEN THE PAST COUPLE DAYS.
SKIES SHOULD CLEAR BY MID-MORNING...FOLLOWED BY A CLEAR AND
SEASONABLY COOL DAY. HIGH PRESSURE WILL BRING CLEAR AND COOL
CONDITIONS TONIGHT.
&&
.SHORT TERM /TONIGHT THROUGH FRIDAY NIGHT/...
AS OF 1 PM EST WEDNESDAY...ZONAL FLOW THU NIGHT THROUGH FRI WILL
GIVE WAY TO WEAK UPPER RIDGING ACROSS THE SE FRI NIGHT AHEAD OF A
SRN STREAM SYSTEM DIGGING INTO TX. MEANWHILE...DRY SFC HIGH PRES
WILL REMAIN PARKED OVER THE REGION THROUGH THE PERIOD. ANY LOW TO
MID LEVEL MOISTURE RETURN FROM THE GULF OF MEXICO AHEAD OF THE SRN
SYSTEM SHOULD REMAIN S OF THE FORECAST AREA THROUGH FRI NIGHT.
TEMPERATURES WILL REMAIN SLIGHTLY BELOW CLIMO THROUGH THE PERIOD.
&&
.LONG TERM /SATURDAY THROUGH WEDNESDAY/...
AS OF MIDDAY WED...BROAD TROUGH ACRS THE NRN TIER OF THE CONUS OVER
THE WEEKEND WILL GRADUALLY AMPLIFY INTO EARLY NEXT WEEK...WITH A NRN
STREAM SHORTWAVE DIVING DOWN OUT OF THE PACIFIC NORTHWEST AND ANOTHER
SRN STREAM WAVE EJECTING OUT OF THE SRN PLAINS. THIS SRN WAVE HAS
BEEN SHOWN IN SOME FASHION BY THE GLOBAL MODELS FOR A FEW DAYS
NOW...AND NOW THEY ARE TRENDING TOWARD A MORE NRN TRACK OF THE WAVE.
CYCLOGENESIS THUS BEGINS OVER THE ERN GULF...WITH THE SFC LOW
CROSSING THE CAROLINAS THEN DEEPENING QUICKLY OFF THE ATLANTIC
COAST. THOUGH MINOR DETAILS STILL DIFFER BETWEEN THE MAJOR MODELS
AND GFS/CMC ENSEMBLE MEMBERS...THERE IS NOW AN INCREASINGLY STRONG
INDICATION OF A PERIOD OF WET WEATHER ACRS THE CWFA LATE SATURDAY
INTO SUNDAY.
CONSENSUS KEEPS THE TRACK OF THE SFC LOW NEAR THE COAST AND THUS OUR
CWFA STAYS ON THE COOL SIDE OF THE SYSTEM...PRECLUDING ANY MENTION OF
THUNDER. 12Z OPNL GFS IS THE WETTEST MODEL...GIVING THE PIEDMONT UP
TO 2 INCHES OF QPF. THIS SEEMS TO BE A RESULT OF ITS INDICATION OF A
SHARPER THERMAL GRADIENT AND TIGHTER SHORTWAVE. ENSEMBLES GENERALLY
KEEP THE MORE SIGNIFICANT QPF ON THE WARM SIDE OF THE SFC LOW CLOSER
TO THE COAST. HAVE RAISED POPS TO LIKELY SOUTH/EAST OF I-85 CORRIDOR
LATE SAT NIGHT AND SUN MRNG...WITH SOLID CHC ELSEWHERE. QPF IS IN THE
MIDDLE OF THE GUID RANGE...GENERALLY 3/4 TO 1 INCH. VERTICAL PROFILES
WITH STRONG WARM NOSE SUGGEST FREEZING RAIN WOULD RESULT IF ANY SFC
TEMPS WERE BELOW FREEZING...BUT GIVEN CLOUD COVER OVERNIGHT SAT NIGHT
I FAVORED WARMER TEMPS ABOVE FREEZING THROUGHOUT THE AREA.
WHILE THE PIEDMONT/FOOTHILLS DRY OUT LATE SUNDAY AS THE LOW DEPARTS
TO THE NORTHEAST...THE LONGWAVE TROUGH DEEPENS AS IT ABSORBS THE NRN
STREAM TROUGH. COLD FROPA THUS OCCURS IN THE MTNS MONDAY WITH ENOUGH
MOISTURE TO EXPECT A BRIEF NW FLOW SNOW EVENT AND BELOW NORMAL TEMPS
MON-TUE. GFS SUGGESTS LOW PRECIP CHANCES MON NIGHT EAST OF THE MTNS
AS WELL. TEMPS SHOULD BEGIN TO MODERATE BY WED WITH LOW POPS
RETURNING AS LOW PRESSURE CROSSES THE GREAT LAKES DRAGGING A WEAK
FRONT ACRS THE SOUTHEAST.
&&
.AVIATION /06Z THURSDAY THROUGH MONDAY/...
AT KCLT...THE LATEST NAM SOUNDINGS ARE MUCH DRIER AT THE AIRFIELD.
IN FACT...THEY ARE TOO DRY BASED ON THE CLOUD DECK WHICH HAS
RECENTLY MOVED IN. THE RAP SOUNDINGS ARE DOING A BETTER JOB...BUT
EVEN THEN THE MOISTURE IS QUITE SHALLOW. SOME WEAK RADAR RETURNS ARE
SHOWING UP NOW ABOUT 30 NM SOUTH OF THE AIRFIELD. BUT THE AIRMASS
DRIES OUT QUICKLY THE FARTHER NORTH ONE GOES. I THINK ANY PCPN WILL
MISS THE AIRFIELD TO THE SOUTH...BUT I DID ADD A VCSH. THERE IS
STILL A SMALL CHANCE OF A BRIEF PERIOD OF FREEZING RAIN...THOUGH I
SUSPECT THE SFC TEMPERATURES WILL STAY A COUPLE DEGREES ABOVE
FREEZING UNDER THE CLOUD DECK. AS FOR CIG HEIGHTS...THEY SHOULD FALL
TO AROUND 4KFT IN A COUPLE HOURS...THEN CLEAR BY 12-13 UTC. LIGHT
WINDS WILL TURN OUT OF THE NORTH AROUND NOON AS A WEAK COLD FRONT
CROSSES THE REGION.
ELSEWHERE...VFR CIGS WILL CONTINUE OVER THE UPSTATE FOR SEVERAL MORE
HOURS. ANY PCPN SHOULD STAY SOUTHEAST OF THE UPSTATE AIRFIELDS. NOT
EXPECTING THE LOWER VFR CIGS TO MAKE IT INTO KHKY OR KAVL. THE CIGS
WILL CLEAR FROM WEST TO EAST BETWEEN 10-12 UTC. WINDS WILL BE
LIGHT...BUT WILL TURN OUT OF THE NORTH LATER TODAY AS A WEAK COLD
FRONT CROSSES THE REGION.
OUTLOOK...VFR CONDITIONS ARE EXPECTED TO PERSIST THROUGH THE WEEK.
LOW PRESSURE WILL DEVELOP OVER THE NORTHERN GULF ON SATURDAY...
CROSSING THE WESTERN CAROLINAS ON SUNDAY. THIS WILL SPREAD RAIN AND
RESTRICTIVE CIGS AND VSBYS ACROSS THE REGION SATURDAY NIGHT AND
SUNDAY.
CONFIDENCE TABLE...
06-12Z 12-18Z 18-24Z 00-06Z
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% HIGH 100%
KHKY HIGH 100% HIGH 100% HIGH 100% HIGH 100%
KGMU HIGH 100% HIGH 100% HIGH 100% HIGH 100%
KAND MED 72% 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...HG
NEAR TERM...MCAVOY
SHORT TERM...HG
LONG TERM...WIMBERLEY
AVIATION...MCAVOY
AREA FORECAST DISCUSSION
NWS GREENVILLE-SPARTANBURG SC
1233 AM EST THU DEC 26 2013
.SYNOPSIS...
SHALLOW MOISTURE FROM THE GULF OF MEXICO WILL BRUSH THE SOUTHEAST
PIEDMONT TODAY. DRY HIGH PRESSURE WILL THEN BUILD OVER THE REGION
THROUGH FRIDAY NIGHT. EXPECT LOW PRESSURE TO TRACK FROM THE GULF OF
MEXICO SATURDAY TO THE CAROLINAS SUNDAY. A COLD FRONT WILL CROSS ON
MONDAY BRINGING COOLER WEATHER FOR TUESDAY.
&&
.NEAR TERM /THROUGH TODAY/...
AS OF MID EVENING...SATELLITE IMAGERY SHOWS THE BAND OF LOW CLOUDS
NOW ACROSS THE I-85 CORRIDOR...STILL MAKING SOME SLOW NWD PROGRESS.
NO PRECIP WAS SEEN ON AREA RADARS...BUT THIS WILL HAVE TO BE WATCHED
TOWARD DAYBREAK AS THE INTERIM MODEL GUIDANCE SHOWED SOME RESPONSE
RIGHT ON THE EDGE OF THE CLT METRO AREA. HOWEVER...THE NEW NAM KEEPS
THE PRECIP A BIT FURTHER EAST...SO HOPEFULLY THIS WILL NOT POSE A
PROBLEM. THE FCST WILL BE KEPT DRY FOR NOW...SO STILL NO CHANGES.
PREVIOUS DISCUSSION...
THE CENTER OF SFC HIGH PRESSURE MOVES OFF THE MID-ATLANTIC COAST
TONIGHT. RETURN FLOW MOISTURE AROUND THIS HIGH AND AHEAD OF A WEAK
COLD FRONT IS BRINGING LOW LEVEL MOISTURE NORTH TOWARD THE CWFA.
THIS MOISTURE MOVES INTO THE I-85 CORRIDOR TONIGHT. THERE IS SOME
ISENTROPIC LIFT WITH THIS MOISTURE AND SOME UPPER DIVERGENCE
ASSOCIATED WITH THE RIGHT ENTRANCE REGION OF A JET STREAK.
HOWEVER...THE SHORT WAVE ASSOCIATED WITH THIS SYSTEM IS WEAK AND
ORIENTED PARALLEL TO THE FLOW. ALSO...MOISTURE IS LIMITED TO THIS
ONE LAYER WITH ONLY CIRRUS ABOVE AND DRY NEAR SFC LEVELS. IN
FACT...THE LOWER LEVEL ISENTROPIC LIFT AND MOISTURE REMAIN WELL TO
OUR SOUTH. SINCE A GUIDANCE BLEND KEEPS OUR AREA DRY WITH ONLY
CLOUDS...HAVE GONE THIS DIRECTION WITH THE FCST. CANNOT RULE OUT
SOME SPRINKLES OR VERY LIGHT RAIN LATE TONIGHT OR EARLY THU MORN.
TEMPS WILL BE BELOW FREEZING BUT DO NOT EXPECT ANY FREEZING RAIN IF
PRECIP DOES DEVELOP AS IT WOULD BE VERY LIGHT NEAR TRACE AMOUNTS.
CLOUDS SHUD CLEAR THU MORN LEAVING A MOSTLY SUNNY AFTERNOON. LOWS
TONIGHT AS MUCH AS 5 DEGREES BELOW NORMAL WITH HIGHS THU NEAR TO
JUST BELOW NORMAL.
&&
.SHORT TERM /TONIGHT THROUGH FRIDAY NIGHT/...
AS OF 1 PM EST WEDNESDAY...ZONAL FLOW THU NIGHT THROUGH FRI WILL
GIVE WAY TO WEAK UPPER RIDGING ACROSS THE SE FRI NIGHT AHEAD OF A
SRN STREAM SYSTEM DIGGING INTO TX. MEANWHILE...DRY SFC HIGH PRES
WILL REMAIN PARKED OVER THE REGION THROUGH THE PERIOD. ANY LOW TO
MID LEVEL MOISTURE RETURN FROM THE GULF OF MEXICO AHEAD OF THE SRN
SYSTEM SHOULD REMAIN S OF THE FORECAST AREA THROUGH FRI NIGHT.
TEMPERATURES WILL REMAIN SLIGHTLY BELOW CLIMO THROUGH THE PERIOD.
&&
.LONG TERM /SATURDAY THROUGH WEDNESDAY/...
AS OF MIDDAY WED...BROAD TROUGH ACRS THE NRN TIER OF THE CONUS OVER
THE WEEKEND WILL GRADUALLY AMPLIFY INTO EARLY NEXT WEEK...WITH A NRN
STREAM SHORTWAVE DIVING DOWN OUT OF THE PACIFIC NORTHWEST AND ANOTHER
SRN STREAM WAVE EJECTING OUT OF THE SRN PLAINS. THIS SRN WAVE HAS
BEEN SHOWN IN SOME FASHION BY THE GLOBAL MODELS FOR A FEW DAYS
NOW...AND NOW THEY ARE TRENDING TOWARD A MORE NRN TRACK OF THE WAVE.
CYCLOGENESIS THUS BEGINS OVER THE ERN GULF...WITH THE SFC LOW
CROSSING THE CAROLINAS THEN DEEPENING QUICKLY OFF THE ATLANTIC
COAST. THOUGH MINOR DETAILS STILL DIFFER BETWEEN THE MAJOR MODELS
AND GFS/CMC ENSEMBLE MEMBERS...THERE IS NOW AN INCREASINGLY STRONG
INDICATION OF A PERIOD OF WET WEATHER ACRS THE CWFA LATE SATURDAY
INTO SUNDAY.
CONSENSUS KEEPS THE TRACK OF THE SFC LOW NEAR THE COAST AND THUS OUR
CWFA STAYS ON THE COOL SIDE OF THE SYSTEM...PRECLUDING ANY MENTION OF
THUNDER. 12Z OPNL GFS IS THE WETTEST MODEL...GIVING THE PIEDMONT UP
TO 2 INCHES OF QPF. THIS SEEMS TO BE A RESULT OF ITS INDICATION OF A
SHARPER THERMAL GRADIENT AND TIGHTER SHORTWAVE. ENSEMBLES GENERALLY
KEEP THE MORE SIGNIFICANT QPF ON THE WARM SIDE OF THE SFC LOW CLOSER
TO THE COAST. HAVE RAISED POPS TO LIKELY SOUTH/EAST OF I-85 CORRIDOR
LATE SAT NIGHT AND SUN MRNG...WITH SOLID CHC ELSEWHERE. QPF IS IN THE
MIDDLE OF THE GUID RANGE...GENERALLY 3/4 TO 1 INCH. VERTICAL PROFILES
WITH STRONG WARM NOSE SUGGEST FREEZING RAIN WOULD RESULT IF ANY SFC
TEMPS WERE BELOW FREEZING...BUT GIVEN CLOUD COVER OVERNIGHT SAT NIGHT
I FAVORED WARMER TEMPS ABOVE FREEZING THROUGHOUT THE AREA.
WHILE THE PIEDMONT/FOOTHILLS DRY OUT LATE SUNDAY AS THE LOW DEPARTS
TO THE NORTHEAST...THE LONGWAVE TROUGH DEEPENS AS IT ABSORBS THE NRN
STREAM TROUGH. COLD FROPA THUS OCCURS IN THE MTNS MONDAY WITH ENOUGH
MOISTURE TO EXPECT A BRIEF NW FLOW SNOW EVENT AND BELOW NORMAL TEMPS
MON-TUE. GFS SUGGESTS LOW PRECIP CHANCES MON NIGHT EAST OF THE MTNS
AS WELL. TEMPS SHOULD BEGIN TO MODERATE BY WED WITH LOW POPS
RETURNING AS LOW PRESSURE CROSSES THE GREAT LAKES DRAGGING A WEAK
FRONT ACRS THE SOUTHEAST.
&&
.AVIATION /06Z THURSDAY THROUGH MONDAY/...
AT KCLT...THE LATEST NAM SOUNDINGS ARE MUCH DRIER AT THE AIRFIELD.
IN FACT...THEY ARE TOO DRY BASED ON THE CLOUD DECK WHICH HAS
RECENTLY MOVED IN. THE RAP SOUNDINGS ARE DOING A BETTER JOB...BUT
EVEN THEN THE MOISTURE IS QUITE SHALLOW. SOME WEAK RADAR RETURNS ARE
SHOWING UP NOW ABOUT 30 NM SOUTH OF THE AIRFIELD. BUT THE AIRMASS
DRIES OUT QUICKLY THE FARTHER NORTH ONE GOES. I THINK ANY PCPN WILL
MISS THE AIRFIELD TO THE SOUTH...BUT I DID ADD A VCSH. THERE IS
STILL A SMALL CHANCE OF A BRIEF PERIOD OF FREEZING RAIN...THOUGH I
SUSPECT THE SFC TEMPERATURES WILL STAY A COUPLE DEGREES ABOVE
FREEZING UNDER THE CLOUD DECK. AS FOR CIG HEIGHTS...THEY SHOULD FALL
TO AROUND 4KFT IN A COUPLE HOURS...THEN CLEAR BY 12-13 UTC. LIGHT
WINDS WILL TURN OUT OF THE NORTH AROUND NOON AS A WEAK COLD FRONT
CROSSES THE REGION.
ELSEWHERE...VFR CIGS WILL CONTINUE OVER THE UPSTATE FOR SEVERAL MORE
HOURS. ANY PCPN SHOULD STAY SOUTHEAST OF THE UPSTATE AIRFIELDS. NOT
EXPECTING THE LOWER VFR CIGS TO MAKE IT INTO KHKY OR KAVL. THE CIGS
WILL CLEAR FROM WEST TO EAST BETWEEN 10-12 UTC. WINDS WILL BE
LIGHT...BUT WILL TURN OUT OF THE NORTH LATER TODAY AS A WEAK COLD
FRONT CROSSES THE REGION.
OUTLOOK...VFR CONDITIONS ARE EXPECTED TO PERSIST THROUGH THE WEEK.
LOW PRESSURE WILL DEVELOP OVER THE NORTHERN GULF ON SATURDAY...
CROSSING THE WESTERN CAROLINAS ON SUNDAY. THIS WILL SPREAD RAIN AND
RESTRICTIVE CIGS AND VSBYS ACROSS THE REGION SATURDAY NIGHT AND
SUNDAY.
CONFIDENCE TABLE...
05-11Z 11-17Z 17-23Z 23-05Z
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% HIGH 100%
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...HG
NEAR TERM...PM/RWH
SHORT TERM...HG
LONG TERM...WIMBERLEY
AVIATION...MCAVOY
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
335 AM CST THU DEC 26 2013
.SHORT TERM...(TODAY THROUGH FRIDAY)
ISSUED AT 335 AM CST THU DEC 26 2013
MAIN WEATHER HAPPENINGS WILL BE MORE LIGHT SNOW FOR TODAY...THEN
SOME MODERATION IN TEMPERATURES ON FRIDAY.
WATER VAPOR SATELLITE LOOP COUPLED WITH RAP 500MB ANALYSIS SHOWS THE
NATION DOMINATED BY A LONG WAVE TROUGH OF LOW PRESSURE WITH
NORTHWEST FLOW INTO THE UPPER MISSISSIPPI RIVER VALLEY REGION. AN
EMBEDDED SHORT WAVE TROUGH WAS MOVING INTO THE DAKOTAS EARLY THIS
MORNING...TOWARD OUR FORECAST AREA. MEANWHILE...IR SATELLITE/SURFACE
OBSERVATIONS SHOWING STRATUS CLOUDS ENSHROUDING THE REGION...TRAPPED
UNDER A WEAK RIDGE OF HIGH PRESSURE THAT EXTENDED FROM THE MID AND
UPPER MISSISSIPPI RIVER VALLEY REGIONS INTO NORTHERN MN. RADAR
MOSAIC AND SURFACE OBSERVATIONS SHOWING SOME LIGHT SNOW FLURRY
ACTIVITY ACROSS PORTIONS OF WEST CENTRAL WISCONSIN AND ACROSS CENTRAL
AND NORTHERN MN. LIGHT SNOW WAS FALLING WITH A BIT MORE FERVOR
ACROSS PORTIONS OF ND IN ADVANCE OF THAT MID-LEVEL TROUGH WITH SOME
VISIBILITY RESTRICTIONS IN THE 4-5SM RANGE.
WILL BE WATCHING THAT MID-LEVEL TROUGH MOVE FROM THE DAKOTAS INTO
OUR REGION BY MID-MORNING WITH DECENT ISENTROPIC LIFT DEPICTED BY
THE NAM AND RAP ON THE 275K SURFACE...OR MAINLY IN THE 900-800MB
LAYER. WILL LIKELY SEE SNOW AMOUNTS IN THE 1/2 TO 1 INCH RANGE
THROUGH THE DAY WITH THIS WAVE BEFORE IT DEPARTS SOUTHEAST BY THIS
EVENING. OTHERWISE...LOOK FOR HIGHS TODAY IN THE TEENS ACROSS NORTH
CENTRAL WI...TO THE MID/UPPER 20S ELSEWHERE.
SOME LINGERING VERY LIGHT SNOW MAY STILL BE SEEN THIS EVENING EAST
OF THE MISSISSIPPI ON THE TAIL END OF THE PASSING TROUGH...BUT THEN
CLOUDS ARE EXPECTED TO DECREASE AFTER MIDNIGHT FROM SOUTHWEST TO
NORTHEAST AS A WEAK RIDGE OF HIGH PRESSURE BUILDS IN BEHIND THE
DEPARTING WAVE.
MODERATING TEMPERATURES EXPECTED ON FRIDAY AS SOUTHWEST WINDS KICK
IN ON THE BACKSIDE OF THE DEPARTING HIGH AND IN ADVANCE OF LOW
PRESSURE MOVING ALONG THE U.S./CANADIAN BORDER. NAM AND ECMWF
BULLISH WITH 925MB TEMPERATURES WARMING INTO THE 0 TO +5C RANGE
WHEREAS THE GFS IS ONLY IN THE -2 TO +3C RANGE. MODEL CONSENSUS
YIELDS HIGHS IN THE UPPER 20S ACROSS CENTRAL WI...TO THE LOWER 30S
FOR AREAS SOUTHWEST OF THE I-94 CORRIDOR. HOWEVER...SOUTHWEST WINDS
IN THE 10-20MPH RANGE WILL MAKE IT FEEL MORE LIKE THE UPPER TEENS TO
LOWER 20S.
.LONG TERM...(FRIDAY NIGHT THROUGH NEW YEARS DAY)
ISSUED AT 335 AM CST THU DEC 26 2013
WARM AIR ADVECTION WILL CONTINUE FRIDAY NIGHT INTO SATURDAY AS THE
AREA REMAINS IN THE WARM SECTOR OF LOW PRESSURE MOVING ACROSS
SOUTHERN ONTARIO CANADA. LOOK FOR LOWS FRIDAY NIGHT IN THE LOW TO
MID 20S WITH HIGHS ON SATURDAY EXPECTED TO TOP OFF IN THE LOWER AND
MIDDLE 30S. AN ARCTIC COLD FRONT IS THEN SLATED TO DROP THROUGH THE
AREA SATURDAY NIGHT.
WILL HAVE TO KEEP AN EYE ON PRECIPITATION TYPE SATURDAY NIGHT AS THE
GFS BUFKIT SOUNDING HINTING AT LOW LEVEL SATURATION UP TO 800MB WITH
NO ICE PRESENT IN THE CLOUD AS THE FRONT MOVES IN. AS SUCH...ADDED
THE MENTION OF FREEZING DRIZZLE INTO THE WEATHER GRIDS ALONG WITH
THE CHANCE OF LIGHT SNOW. BY EARLY SUNDAY MORNING...IT APPEARS THE
SATURATED COLUMN WILL HAVE ICE PRESENT FOR ALL LIGHT SNOW.
BY SUNDAY MORNING...PLAN ON TEMPERATURES DROPPING INTO THE SINGLE
DIGITS AND TEENS ABOVE ZERO WITH ONLY A 2 TO 3 DEGREE RISE DURING
THE DAY SUNDAY. SOME LIGHT SNOW WILL STILL BE POSSIBLE MAINLY EAST OF
THE MISSISSIPPI RIVER. BRISK NORTHWEST WINDS WILL ADD TO THE CHILL
SUNDAY AS WELL WITH WIND CHILL VALUES FALLING INTO THE -15 TO
-25 DEGREE RANGE ACROSS SOUTHEAST MN/NORTHEAST IA IN
THE AFTERNOON.
VERY COLD WIND CHILLS WILL BE SEEN SUNDAY NIGHT...LASTING THROUGH
TUESDAY MORNING//COLDEST EARLY MONDAY MORNING// AS THE ARCTIC AIR
CONTINUES TO SPILL INTO THE REGION. WIND CHILL HEADLINES WILL LIKELY
BE NEEDED. LOWEST WIND CHILL VALUES MONDAY MORNING COULD BE AS LOW
AS -25 TO -35 DEGREES. SLIGHT MODERATION IN TEMPERATURES MAY BE SEEN
LATER TUESDAY THROUGH WEDNESDAY AS THE HEART OF THE ARCTIC AIR MOVES
MORE INTO THE GREAT LAKES REGION.
EMBEDDED SHORTWAVE TROUGHS EMBEDDED IN THE NORTHWEST FLOW WILL ALSO
GIVE THE AREA PERIODIC LIGHT SNOW CHANCES FROM MONDAY NIGHT THROUGH
WEDNESDAY.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z THURSDAY NIGHT)
ISSUED AT 1129 PM CST WED DEC 25 2013
VFR CONDITIONS CURRENTLY EXIST AT THE TAF SITES BUT THAT IS ABOUT
TO CHANGE SOON. MVFR STRATUS IS ENCROACHING ON THE TAF SITES FROM
THE WEST NEAR AUSTIN MN...WHICH STRETCHES NORTHWEST TOWARDS ST
CLOUD. THIS STRATUS LOOKS TO MOVE INTO RST BY 0630Z AND LSE BY
0830Z. ALONG WITH THE STRATUS COMES POTENTIAL FOR SNOW...AS NOTED
BY MVFR VISIBILITIES AT ST CLOUD. THESE MVFR VISIBILITIES COULD
OCCUR PERIODICALLY AT RST AND LSE. MODEL FORECASTS SUPPORT THE
PREVIOUS TAF THINKING OF THE BULK OF THE SNOW ENDING BY 12Z.
BETWEEN 12-18Z...RST SHOULD SEE THE MVFR CEILING SCATTER OUT AS
SOME DRIER AIR WORKS IN FROM THE WEST. UNSURE IF THIS DRIER AIR
CAN GET INTO LSE...THOUGH...AS THAT WARM FRONT BECOMES STUCK
NEARBY. THUS HAVE HELD ONTO THE MVFR CEILING AND POTENTIAL FOR
SOME FLURRIES THROUGH THE 12-18Z PERIOD THERE. THEN IN THE
AFTERNOON...ANOTHER WAVE OF LIGHT SNOW REMAINS ON TAP TO MOVE
THROUGH THE TAF SITES WITH UP TO 1 INCH OF ACCUMULATION. APPEARS
THE PEAK TIME FOR SOME IFR VISIBILITIES...PARTICULARLY AT LSE
GIVEN THE LOCATION OF THE WARM FRONT AND EXPECTED TRACK OF THE
SNOW...WOULD OCCUR BETWEEN 20-23Z. SNOW SHOULD BE OUT OF THE TAF
SITES BY 00Z...WITH AN MVFR CEILING PERSISTING THROUGH MUCH OF
TONIGHT AS A WEAK PRESSURE GRADIENT PREVENTS ANY MOVEMENT TO THE
CLOUDS.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...DAS
LONG TERM...DAS
AVIATION...AJ
AREA FORECAST DISCUSSION
NWS TAUNTON MA
1015 AM EST THU DEC 26 2013
.SYNOPSIS...
A WEAK...FAST MOVING DISTURBANCE WILL BRING A MIX OF RAIN AND
SNOW FOR THE REGION TODAY. WHILE COOL FOR FRIDAY...MILDER
CONDITIONS MOVE IN FOR THE WEEKEND. LOW PRESSURE WILL MOVE
NORTHEAST FROM THE GULF OF MEXICO WILL PASS NEAR NANTUCKET SUNDAY
NIGHT...THEN MOVE SOUTH OF NOVA SCOTIA MONDAY MORNING. FRIGID AIR
WILL INVADE THE REGION BY TUESDAY.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
955 AM UPDATE...
BAND OF LIGHT SNOW HAS DEVELOPED ACROSS EASTERN MA AS SEEN ON
LATEST KBOX 88D RADAR IMAGERY. MORE LIGHT SNOW HAS MOVED INTO S
NH/W MA/N CENTRAL CT AHEAD OF APPROACHING LOW PRES MOVING OUT OF
THE GREAT LAKES THIS MORNING. NOTING LIGHT RAIN REPORTED ALONG THE
S COAST WITH TEMPS MAINLY IN THE MID TO UPPER 30S WITH S-SE WINDS
UP TO 10 MPH...WHILE LIGHT NORTHERLY WINDS CONTINUE WHERE THE SNOW
HAS BROKEN OUT.
TEMPS/DEWPTS HAVE BEEN RUNNING SEVERAL DEGS LOWER THAN PREVIOUS
FORECAST ACROSS THE INTERIOR SO HAVE ADJUSTED TO BRING CURRENT.
THIS MAY SLOW THE TEMP RISE A BIT ACROSS INTERIOR E MA/N RI.
REMAINING GRIDS ALSO UPDATED TO BRING CURRENT.
PREVIOUS DISCUSSION...
STRONGER NORTHERN STREAM IMPULSE THROUGH THE BROADER TROUGH
REGIME INVOKES A WEAK AREA OF LOW PRES SOUTH AND OFFSHORE OF NEW
ENGLAND WITHIN THE BETTER BAROCLINIC ZONE BY MIDDAY...QUICKLY
MOVING NORTHEASTWARD AND AMPLIFYING ACROSS THE GULF OF MAINE BY
EVENING.
EXPECT THE HEAVIEST OF PRECIP IMPACTS E-SE PORTIONS OF SOUTHERN
NEW ENGLAND WITH ONE TO TWO TENTHS /THE GREATEST OF WHICH WILL BE
ACROSS THE EASTERN CAPE AND NANTUCKET/. LESSER AMOUNTS EXPECTED
FOR THE NORTH AND WEST INTERIOR. CLOUDS ON THE INCREASE SOUTH AND
WEST PRESENTLY WILL BEGIN TO CLEAR OUT LATE.
BUT SOME QUESTION AS TO HOW QUICKLY ARCTIC AIR WILL SCOUR OUT. NOT A
ROBUST SYSTEM AND ONSHORE SOUTHERLY FLOW WILL BE LIGHT. WHILE MILDER
AIR WILL WORK IN SOUTH TO NORTH...CONSIDERING HOW LONG WE HAVE BEEN
IN AN ARCTIC GRIP...FEEL THE PROGRESSION OF MILDER AIR WILL BE SLOW
AGAINST THE ARCTIC AIRMASS. SUSPECT COASTAL LOCATIONS AND ADJACENT
PLAINS WILL WARM ABOVE FREEZING...WHILE INTERIOR LOCALES /ESPECIALLY
THOSE WITH A REMAINING SNOWPACK/ WILL STAY AT OR BELOW FREEZING
THROUGHOUT THE EVENT. WHILE THE HRRR MAY BE TOO COLD...THE WRF-ARW
2M TEMPS ARE A GOOD APPROXIMATION AS TO THINKING.
IN THE END...SNOW IS EXPECTED INITIALLY MIXING OVER TO RAIN FOR
COASTAL COMMUNITIES AND ADJACENT PLAINS...WITH MAINLY ALL SNOW FOR
THE NORTHERN AND WESTERN INTERIOR /NORTH AND WEST OF I-84 TO I-90 TO
I-95 AS AN APPROXIMATION/. ROUGHLY 1 TO 2 INCHES FOR THE HIGHER
TERRAIN OF THE BERKSHIRES/WORCESTER HILLS/MONADNOCKS...WITH A TRACE
TO AN INCH ELSEWHERE EXCEPT COASTAL COMMUNITIES. FOR AREAS MIXING
OVER TO RAIN...INITIAL SNOW ACCUMS WILL ALL BUT WASH AWAY.
HIGHS TODAY AROUND THE UPPER 20S TO LOW 30S /WARMEST CONDITIONS
ALONG THE IMMEDIATE SHORES...CAPE AND ISLANDS/.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM FRIDAY/...
TONIGHT....
HIGH PRES AND COLDER AIR WORKING IN. WHILE THE SYSTEM CLEARS OUT...
WILL SEE SOME LOW- TO MID-LEVEL CLOUDS LINGER ASSOCIATED WITH FETCH
OFF THE LAKES AND ADDITIONAL WEAK IMPULSES ROUNDING THE BROADER FLOW
REGIME ALOFT. COLD AIR ADVECTION THROUGH THE LOW-LEVELS ALLOWS FOR
STEEPENING LAPSE RATES. MIX-DOWN OF FASTER MOMENTUM CERTAINLY
POSSIBLE WITH GUSTS OF 20 TO 25 MPH...ESPECIALLY ALONG THE SOUTH-
SOUTHEAST COAST WITH ADJACENT WARMER WATERS. NOT ARCTIC COLD...LOWS
AROUND THE UPPER-TEENS TO LOW-20S /WARMER ALONG IMMEDIATE SHORES/.
FRIDAY...
HIGH PRES CONTINUING TO BUILD...SHIFTING SOUTH AND EAST. WILL SEE
WESTERLY FLOW DIMINISH TURNING SOUTHWESTERLY...BECOMING LIGHT.
LINGERING LOW- TO MID-LEVEL CLOUDS WITH FETCH OFF THE LAKES. STILL
COLD WITH H925 TEMPS AROUND -4 TO -6C /H85 AROUND -10C/. HIGHS
AROUND THE LOW- TO MID-30S ANTICIPATED.
&&
.LONG TERM /FRIDAY NIGHT THROUGH WEDNESDAY/...
BIG PICTURE... UPPER LOW CENTERED OVER BAFFIN ISLAND/HUDSON BAY WITH
CYCLONIC FLOW OVER THE NORTHEAST USA WEAKENING EARLY IN THE
FORECAST...THEN STRENGTHENING AGAIN BY NEW YEARS EVE. THIS
CONTINUES TO FAVOR MODERATING TEMPS OVER THE WEEKEND...THEN A RETURN
TO BELOW NORMAL TEMPS EARLY NEXT WEEK. THE MAIN CHANGE IN THIS
PATTERN SEEMS TO BE A 24-HOUR DELAY IN THE ONSET OF NEXT WEEK/S
CHILL. THE UPPER JET AND SOUTHWEST FLOW DON/T MOVE EAST OF NEW
ENGLAND UNTIL MONDAY NIGHT.
MEANWHILE THE NORTHERN AND SOUTHERN UPPER JETS ARE NOW FORECAST TO
PHASE DURING SUNDAY...ALLOWING SOUTHERN STREAM SHORTWAVE TO TAP A
MORE PRONOUNCED BAROCLINIC ZONE AS IT MOVES PAST NEW ENGLAND. THE
PHASING SUGGESTS DEEPENING OF THE UPPER TROUGH TO OUR WEST RESULTING
IN MORE OF A SOUTHWEST FLOW ALOFT. THIS LEAVES ROOM FOR THE SURFACE
COASTAL LOW TO EDGE CLOSER TO THE COAST LATER SUNDAY/SUNDAY NIGHT.
THIS IS A STORMIER SCENARIO FOR US THAN WAS DEPICTED 24 HOURS AGO.
WE WILL NEED TO MONITOR THAT THIS SUDDEN CHANGE DOESN/T GO BACK THE
OTHER WAY JUST AS FAST.
MODELS... GFS AND ECMWF ARE SIMILAR WITH THEIR SURFACE ISOBARS/UPPER
CONTOURS/UPPER JET WIND SPEEDS THROUGH SUNDAY NIGHT. SMALL
DIFFERENCES DEVELOP MONDAY THROUGH WEDNESDAY. WE FAVOR A BLEND OF
THE LONG RANGE GUIDANCE.
THE DAILIES...
FRIDAY NIGHT-SATURDAY... COLD NORTHWEST FLOW FLATTENS TO A WEST-EAST
FLOW AS SHORTWAVES IN THE NORTHERN AND SOUTHERN STREAMS MOVE INTO
THE PLAINS. THE NORTHERN STREAM SUPPORTS A STALLED COLD FRONT ALONG
THE CANADIAN BORDER WITH LOW PRESSURE WAVES RIPPLING ALONG IT.
MEANWHILE HIGH PRESSURE IS IN PLACE ACROSS THE SOUTHEAST AND MID
ATLANTIC STATES. LIGHT FLOW AND DRY AIR WILL ALLOW FRIDAY NIGHT
TEMPS TO DIP INTO THE TEENS AND 20S. THEN THE MILDER AIR WILL START
FLOWING IN A WEST-SOUTHWEST FLOW. CLOUDS ASSOCIATED WITH THE
STALLED COLD FRONT WILL AFFECT NORTHERN NEW ENGLAND SATURDAY AND MAY
BRING PARTLY CLOUDY SKIES TO PARTS OF OUR AREA. BUT OVERALL IT WILL
BE A FAIR DAY WITH TEMPS REACHING THE UPPER 30S AND 40S.
SUNDAY-MONDAY... SOUTHERN STREAM LOW PRESSURE DEVELOPS OVER THE GULF
OF MEXICO LATE SATURDAY AND MOVES UP THE EAST COAST ON SUNDAY. AS
NOTED ABOVE...THE TWO JET STREAMS ARE NOW EXPECTED TO PHASE ON
SUNDAY ALLOWING THE COASTAL SYSTEM TO MOVE CLOSER TO THE COAST. IF
THIS VERIFIES...IT WILL ALLOW PRECIPITATION TO REACH MOST OR ALL OF
OUR AREA LATER SUNDAY AND SUNDAY NIGHT. TEMPS IN THE VERTICAL WILL
BE ABOVE FREEZING SOUTH OF THE MASS PIKE WHILE AREAS FARTHER NORTH
MAY HAVE TEMPS EITHER SIDE OF FREEZING. THIS WILL MEAN RAIN FOR OUR
SOUTHERN AREAS AND A RAIN/SNOW MIX IN THE NORTH...POSSIBLY ALL SNOW
IN SOUTHERN NH. THE CURRENT MODEL INFORMATION IS NOTICEABLY
DIFFERENT FROM THE INFO 24 HOURS AGO SO CONFIDENCE IS VERY LIMITED
FOR THIS FORECAST. ALSO SMALL CHANGES IN THE FLOW OVER THE NEXT 3-4
DAYS COULD PUSH THE RAIN TEMPERATURES FARTHER NORTH OR THE SNOW
TEMPERATURES FARTHER SOUTH. SO STAY TUNED. THE UPPER FLOW WILL
REMAIN OPEN TO THE EAST ALLOWING THE COASTAL STORM TO RACE OFF
THROUGH THE MARITIMES SUNDAY NIGHT. MONDAY LOOKS SUNNIER/DRIER AND
COOLER...BUT NOT UNSEASONABLY SO.
TUESDAY-WEDNESDAY... WITH THE UPPER JET MOVING OFFSHORE MONDAY
NIGHT...THE WAY WILL BE OPEN FOR ARCTIC AIR TO RETURN TO SOUTHERN
NEW ENGLAND. TEMPS AT 925 MB WILL BE 10C COLDER WITH VALUES TUESDAY
AT -12C TO -14C. FULLY MIXED THIS WOULD SUPPORT MAX TEMPS IN THE
20S. DEWPOINTS WILL DIVE TO THE SINGLE NUMBERS AND BELOW ZERO. THIS
WILL MAKE ROOM FOR NIGHTTIME MIN TEMPS IN THE SINGLE NUMBERS AND
LOWER TEENS.
&&
.AVIATION /15Z THURSDAY THROUGH MONDAY/...
FORECASTER CONFIDENCE LEVELS...
LOW...LESS THAN 30 PERCENT.
MODERATE...30 TO 60 PERCENT.
HIGH...GREATER THAN 60 PERCENT.
NEAR TERM /THROUGH FRIDAY/...HIGH CONFIDENCE.
10 AM UPDATE...
MAINLY MVFR TO LOCALLY IFR CONDITIONS ACROSS E MA/RI INTO S
CENTRAL NH WITH -SN /-RA ACROSS SE MA AND RI/. VFR CONDITIONS
ACROSS SW NH/CENTRAL-W MA AND N CT WILL BECOME LOCALLY MVFR IN
-SN. ALSO EXPECT BRIEF IFR CONDITIONS ACROSS HIGHER INLAND
TERRAIN.
PREVIOUS DISCUSSION...
IMPROVEMENT BEGINS TOWARDS EVENING AS WINDS REVERT WESTERLY AND
BECOME BLUSTERY...GUSTS DEVELOPING OVERNIGHT INTO FRIDAY THE
STRONGEST OF WHICH WILL LIKELY IMPACT SHORELINE TERMINALS. LOW TO
MID LEVEL CLOUDS FEW-SCT WILL LIKELY FILTER ACROSS THE TERMINALS.
KBOS TAF...HIGH CONFIDENCE IN TAF. LOWER CONFIDENCE WITH EXACT
TIMING OF IMPACTS. INITIAL SNOW ACCUMS OF AROUND A TENTH OR TWO IN
THE MORNING WILL WASH AWAY AS SNOW MIXES OVER TO RAIN DURING THE
MORNING HOURS.
KBDL TAF...HIGH CONFIDENCE IN TAF. MUCH OF THE ACTIVITY STAYS EAST
OF THE TERMINAL. EXPECTING JUST SOME FLURRIES TO A BRIEF LIGHT
SNOW SHOWER THAT WILL YIELD AROUND A TRACE OF SNOW ACCUM AT MOST.
OUTLOOK...FRIDAY NIGHT THROUGH MONDAY
FRIDAY NIGHT THROUGH SUNDAY MORNING...HIGH CONFIDENCE. VFR.
SUNDAY AFTERNOON THROUGH MONDAY...MODERATE CONFIDENCE. CIGS AND
VSBYS WILL LOWER TO MVFR IN DEVELOPING RAIN SUNDAY AFTERNOON AND
EVENING. PRECIPITATION MAY MIX WITH SNOW OR BECOME ALL SNOW IN
SOUTHERN NH AND PARTS OF NORTHERN MASS. IFR CONDITIONS POSSIBLE
SUNDAY NIGHT. PRECIPITATION ENDS BY MONDAY MORNING AND CONDITIONS
WILL IMPROVE TO VFR.
&&
.MARINE...
FORECASTER CONFIDENCE LEVELS...
LOW...LESS THAN 30 PERCENT.
MODERATE...30 TO 60 PERCENT.
HIGH...GREATER THAN 60 PERCENT.
NEAR TERM /THROUGH FRIDAY/...HIGH CONFIDENCE.
10 AM UPDATE...
SOUTHERLY WINDS BEGINNING TO INCREASE ACROSS THE SOUTHERN OPEN
WATERS. NOTING PK WND UP TO 25 KT AT BUZZARDS BAY TOWER AT 15Z AND
23 KT AT 44013. SEAS AROUND 3 FT AT THE BUOYS...WHICH WILL SLOWLY
BUILD THIS AFTERNOON AS WINDS INCREASE. HAVE CONTINUED SMALL
CRAFTS AS EXPECT WINDS/SEAS TO MAKE CRITERIA AS WEAK LOW
APPROACHES. MAY SEE PERIOD OF LIGHT SNOW ACROSS THE EASTERN WATERS
N OF CAPE COD EARLY...OTHERWISE SHOULD SEE LIGHT RAIN WITH SOME
VSBY RESTRICTIONS.
PREVIOUS DISCUSSION...
OVERNIGHT...COVERAGE OF SMALL CRAFT ADVISORIES EXTENDS IN
RESPONSE TO WINDS BACKING OUT OF THE WEST BEHIND THE DEPARTING
SYSTEM AND BECOMING BLUSTERY WITH GUSTS UP TO 25 KTS. CONDITIONS
CONTINUE THROUGH FRIDAY. SEAS BUILDING OVER THE OUTER WATERS...5
TO 7 FEET.
OUTLOOK...FRIDAY NIGHT THROUGH MONDAY...
MODERATE CONFIDENCE.
FRIDAY NIGHT-SATURDAY...WEST TO SOUTHWEST WINDS MAY GUST NEAR 25
KNOTS. SEAS WILL SUBSIDE BELOW 5 FEET FRIDAY NIGHT...BUT THEN BUILD
ON SATURDAY TO 5-7 FEET ESPECIALLY ON THE OUTER WATERS. A SMALL
CRAFT ADVISORY MAY BE NEEDED FOR PARTS OF THE MASS AND RI WATERS.
SUNDAY...COASTAL LOW PRESSURE MOVES UP THE EAST COAST. VARIABLE
WINDS WILL BECOME NORTHEAST LATE SUNDAY AND THEN NORTHWEST MONDAY.
SPEEDS WILL BE AROUND 25 KNOTS...WHILE THE EXPOSED WATERS WILL SEE
SEAS BUILD TO 5 TO 7 FEET. SMALL CRAFT ADVISORY MAY BE NEEDED FOR
PARTS OF THE MASS AND RI WATERS.
&&
.BOX WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
MA...NONE.
NH...NONE.
RI...NONE.
MARINE...SMALL CRAFT ADVISORY FROM 6 PM THIS EVENING TO 2 AM EST FRIDAY
FOR ANZ231-232-251.
SMALL CRAFT ADVISORY FROM 6 PM THIS EVENING TO MIDNIGHT EST
TONIGHT FOR ANZ233-234.
SMALL CRAFT ADVISORY FROM 4 PM THIS AFTERNOON TO 2 AM EST
FRIDAY FOR ANZ235-237.
SMALL CRAFT ADVISORY FROM 1 PM THIS AFTERNOON TO 7 PM EST
FRIDAY FOR ANZ250-254>256.
&&
$$
SYNOPSIS...WTB/SIPPRELL
NEAR TERM...WTB/EVT
SHORT TERM...SIPPRELL
LONG TERM...WTB
AVIATION...WTB/SIPPRELL/EVT
MARINE...WTB/SIPPRELL/EVT
AREA FORECAST DISCUSSION
NWS TAUNTON MA
632 AM EST THU DEC 26 2013
.SYNOPSIS...
A WEAK AND QUICK DISTURBANCE WILL BRING A MIX OF RAIN AND SNOW FOR
THE REGION TODAY. WHILE COOL FOR FRIDAY...MILDER CONDITIONS MOVE
IN FOR THE WEEKEND. LOW PRESSURE WILL MOVE NORTHEAST FROM THE
GULF OF MEXICO WILL PASS NEAR NANTUCKET SUNDAY NIGHT...THEN MOVE
SOUTH OF NOVA SCOTIA MONDAY MORNING. FRIGID AIR WILL INVADE THE
REGION BY TUESDAY.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
7 AM UPDATE...
PATCHY LIGHT FLAKES. OTHERWISE CLOUDS AND DRY AIR. DEWPOINT
DEPRESSIONS AT 6 AM WERE RUNNING 5-10F. MAIN CHANGE TO FORECAST IS
TO REMOVE FREEZING DRIZZLE...HARD TO SEE THIS WITH DEWPOINT
DEPRESSIONS AS THEY ARE.
PREVIOUS DISCUSSION...
STRONGER NORTHERN STREAM IMPULSE THROUGH THE BROADER TROUGH
REGIME INVOKES A WEAK AREA OF LOW PRES SOUTH AND OFFSHORE OF NEW
ENGLAND WITHIN THE BETTER BAROCLINIC ZONE BY MIDDAY...QUICKLY
MOVING NORTHEASTWARD AND AMPLIFYING ACROSS THE GULF OF MAINE BY
EVENING.
DURING THIS AMPLIFICATION...ATTENDANT DYNAMICS AND JET STREAK
ENHANCE SOUTH-SOUTHWESTERLY LOW- TO MID-LEVEL FLOW RESULTING IN
LOCALIZED MOISTURE CONVERGENCE ALONG THE LEADING WARM-FRONT /N-NE
QUADRANT OF THE SURFACE LOW/ WHERE FRONTOGENESIS/ISENTROPIC FORCING
IS MAXIMIZED.
ALREADY THIS MORNING...RADAR ECHOES ARE BUILDING ACROSS UPSTATE NY
OUT AHEAD OF THE NORTHERN STREAM IMPULSE...WHILE PER SATELLITE
TRENDS...LOW CLOUDS AND MOISTURE ARE BEING DRAWN UP FROM THE SOUTH.
SO WITH CERTAINTY...THE HEAVIEST OF PRECIP IMPACTS E/SE PORTIONS OF
SOUTHERN NEW ENGLAND WITH ONE TO TWO TENTHS /THE GREATEST OF WHICH
WILL BE ACROSS THE EASTERN CAPE AND NANTUCKET/. LESSER AMOUNTS
EXPECTED FOR THE NORTH AND WEST INTERIOR. CLOUDS ON THE INCREASE
SOUTH AND WEST PRESENTLY WILL BEGIN TO CLEAR OUT LATE.
BUT SOME QUESTION AS TO HOW QUICKLY ARCTIC AIR WILL SCOUR OUT. NOT A
ROBUST SYSTEM AND ONSHORE SOUTHERLY FLOW WILL BE LIGHT. WHILE MILDER
AIR WILL WORK IN SOUTH TO NORTH...CONSIDERING HOW LONG WE HAVE BEEN
IN AN ARCTIC GRIP...FEEL THE PROGRESSION OF MILDER AIR WILL BE SLOW
AGAINST THE ARCTIC AIRMASS. SUSPECT COASTAL LOCATIONS AND ADJACENT
PLAINS WILL WARM ABOVE FREEZING...WHILE INTERIOR LOCALES /ESPECIALLY
THOSE WITH A REMAINING SNOWPACK/ WILL STAY AT OR BELOW FREEZING
THROUGHOUT THE EVENT. WHILE THE HRRR MAY BE TOO COLD...THE WRF-ARW
2M TEMPS ARE A GOOD APPROXIMATION AS TO THINKING.
IN THE END...SNOW IS EXPECTED INITIALLY MIXING OVER TO RAIN FOR
COASTAL COMMUNITIES AND ADJACENT PLAINS...WITH MAINLY ALL SNOW FOR
THE NORTHERN AND WESTERN INTERIOR /NORTH AND WEST OF I-84 TO I-90 TO
I-95 AS AN APPROXIMATION/. ROUGHLY 1 TO 2 INCHES FOR THE HIGHER
TERRAIN OF THE BERKSHIRES/WORCESTER HILLS/MONADNOCKS...WITH A TRACE
TO AN INCH ELSEWHERE EXCEPT COASTAL COMMUNITIES. FOR AREAS MIXING
OVER TO RAIN...INITIAL SNOW ACCUMS WILL ALL BUT WASH AWAY.
HIGHS TODAY AROUND THE UPPER-20S TO LOW-30S /WARMEST CONDITIONS
ALONG THE IMMEDIATE SHORES...CAPE AND ISLANDS/.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM FRIDAY/...
TONIGHT....
HIGH PRES AND COLDER AIR WORKING IN. WHILE THE SYSTEM CLEARS OUT...
WILL SEE SOME LOW- TO MID-LEVEL CLOUDS LINGER ASSOCIATED WITH FETCH
OFF THE LAKES AND ADDITIONAL WEAK IMPULSES ROUNDING THE BROADER FLOW
REGIME ALOFT. COLD AIR ADVECTION THROUGH THE LOW-LEVELS ALLOWS FOR
STEEPENING LAPSE RATES. MIX-DOWN OF FASTER MOMENTUM CERTAINLY
POSSIBLE WITH GUSTS OF 20 TO 25 MPH...ESPECIALLY ALONG THE SOUTH-
SOUTHEAST COAST WITH ADJACENT WARMER WATERS. NOT ARCTIC COLD...LOWS
AROUND THE UPPER-TEENS TO LOW-20S /WARMER ALONG IMMEDIATE SHORES/.
FRIDAY...
HIGH PRES CONTINUING TO BUILD...SHIFTING SOUTH AND EAST. WILL SEE
WESTERLY FLOW DIMINISH TURNING SOUTHWESTERLY...BECOMING LIGHT.
LINGERING LOW- TO MID-LEVEL CLOUDS WITH FETCH OFF THE LAKES. STILL
COLD WITH H925 TEMPS AROUND -4 TO -6C /H85 AROUND -10C/. HIGHS
AROUND THE LOW- TO MID-30S ANTICIPATED.
&&
.LONG TERM /FRIDAY NIGHT THROUGH WEDNESDAY/...
BIG PICTURE... UPPER LOW CENTERED OVER BAFFIN ISLAND/HUDSON BAY WITH
CYCLONIC FLOW OVER THE NORTHEAST USA WEAKENING EARLY IN THE
FORECAST...THEN STRENGTHENING AGAIN BY NEW YEARS EVE. THIS
CONTINUES TO FAVOR MODERATING TEMPS OVER THE WEEKEND...THEN A RETURN
TO BELOW NORMAL TEMPS EARLY NEXT WEEK. THE MAIN CHANGE IN THIS
PATTERN SEEMS TO BE A 24-HOUR DELAY IN THE ONSET OF NEXT WEEK/S
CHILL. THE UPPER JET AND SOUTHWEST FLOW DON/T MOVE EAST OF NEW
ENGLAND UNTIL MONDAY NIGHT.
MEANWHILE THE NORTHERN AND SOUTHERN UPPER JETS ARE NOW FORECAST TO
PHASE DURING SUNDAY...ALLOWING SOUTHERN STREAM SHORTWAVE TO TAP A
MORE PRONOUNCED BAROCLINIC ZONE AS IT MOVES PAST NEW ENGLAND. THE
PHASING SUGGESTS DEEPENING OF THE UPPER TROUGH TO OUR WEST RESULTING
IN MORE OF A SOUTHWEST FLOW ALOFT. THIS LEAVES ROOM FOR THE SURFACE
COASTAL LOW TO EDGE CLOSER TO THE COAST LATER SUNDAY/SUNDAY NIGHT.
THIS IS A STORMIER SCENARIO FOR US THAN WAS DEPICTED 24 HOURS AGO.
WE WILL NEED TO MONITOR THAT THIS SUDDEN CHANGE DOESN/T GO BACK THE
OTHER WAY JUST AS FAST.
MODELS... GFS AND ECMWF ARE SIMILAR WITH THEIR SURFACE ISOBARS/UPPER
CONTOURS/UPPER JET WIND SPEEDS THROUGH SUNDAY NIGHT. SMALL
DIFFERENCES DEVELOP MONDAY THROUGH WEDNESDAY. WE FAVOR A BLEND OF
THE LONG RANGE GUIDENCE.
THE DAILIES...
FRIDAY NIGHT-SATURDAY... COLD NORTHWEST FLOW FLATTENS TO A WEST-EAST
FLOW AS SHORTWAVES IN THE NORTHERN AND SOUTHERN STREAMS MOVE INTO
THE PLAINS. THE NORTHERN STREAM SUPPORTS A STALLED COLD FRONT ALONG
THE CANADIAN BORDER WITH LOW PRESSURE WAVES RIPPLING ALONG IT.
MEANWHILE HIGH PRESSURE IS IN PLACE ACROSS THE SOUTHEAST AND MID
ATLANTIC STATES. LIGHT FLOW AND DRY AIR WILL ALLOW FRIDAY NIGHT
TEMPS TO DIP INTO THE TEENS AND 20S. THEN THE MILDER AIR WILL START
FLOWING IN A WEST-SOUTHWEST FLOW. CLOUDS ASSOCIATED WITH THE
STALLED COLD FRONT WILL AFFECT NORTHERN NEW ENGLAND SATURDAY AND MAY
BRING PARTLY CLOUDY SKIES TO PARTS OF OUR AREA. BUT OVERALL IT WILL
BE A FAIR DAY WITH TEMPS REACHING THE UPPER 30S AND 40S.
SUNDAY-MONDAY... SOUTHERN STREAM LOW PRESSURE DEVELOPS OVER THE GULF
OF MEXICO LATE SATURDAY AND MOVES UP THE EAST COAST ON SUNDAY. AS
NOTED ABOVE...THE TWO JET STREAMS ARE NOW EXPECTED TO PHASE ON
SUNDAY ALLOWING THE COASTAL SYSTEM TO MOVE CLOSER TO THE COAST. IF
THIS VERIFIES...IT WILL ALLOW PRECIPITATION TO REACH MOST OR ALL OF
OUR AREA LATER SUNDAY AND SUNDAY NIGHT. TEMPS IN THE VERTICAL WILL
BE ABOVE FREEZING SOUTH OF THE MASS PIKE WHILE AREAS FARTHER NORTH
MAY HAVE TEMPS EITHER SIDE OF FREEZING. THIS WILL MEAN RAIN FOR OUR
SOUTHERN AREAS AND A RAIN/SNOW MIX IN THE NORTH...POSSIBLY ALL SNOW
IN SOUTHERN NH. THE CURRENT MODEL INFORMATION IS NOTICEABLY
DIFFERENT FROM THE INFO 24 HOURS AGO SO CONFIDENCE IS VERY LIMITED
FOR THIS FORECAST. ALSO SMALL CHANGES IN THE FLOW OVER THE NEXT 3-4
DAYS COULD PUSH THE RAIN TEMPERATURES FARTHER NORTH OR THE SNOW
TEMPERATURES FARTHER SOUTH. SO STAY TUNED. THE UPPER FLOW WILL
REMAIN OPEN TO THE EAST ALLOWING THE COASTAL STORM TO RACE OFF
THROUGH THE MARITIMES SUNDAY NIGHT. MONDAY LOOKS SUNNIER/DRIER AND
COOLER...BUT NOT UNSEASONABLY SO.
TUESDAY-WEDNESDAY... WITH THE UPPER JET MOVING OFFSHORE MONDAY
NIGHT...THE WAY WILL BE OPEN FOR ARCTIC AIR TO RETURN TO SOUTHERN
NEW ENGLAND. TEMPS AT 925 MB WILL BE 10C COLDER WITH VALUES TUESDAY
AT -12C TO -14C. FULLY MIXED THIS WOULD SUPPORT MAX TEMPS IN THE
20S. DEWPOINTS WILL DIVE TO THE SINGLE NUMBERS AND BELOW ZERO. THIS
WILL MAKE ROOM FOR NIGHTTIME MIN TEMPS IN THE SINGLE NUMBERS AND
LOWER TEENS.
&&
.AVIATION /12Z THURSDAY THROUGH MONDAY/...
FORECASTER CONFIDENCE LEVELS...
LOW...LESS THAN 30 PERCENT.
MODERATE...30 TO 60 PERCENT.
HIGH...GREATER THAN 60 PERCENT.
NEAR TERM /THROUGH FRIDAY/...HIGH CONFIDENCE.
7 AM UPDATE...
VARIABLE CIGS BUT WITH AREAS OF 1500-2000 FEET IN THE NORTH AND
3000-3500 FEET IN THE SOUTH. IFR CIGS IN THE HILLS SUCH AS AT
ORH. EXPECT CONTINUED MVFR CIGS AND AREAS OF IFR VSBYS IN SNOW
LATER THIS MORNING/EARLY AFTERNOON. SNOW CHANGES TO RAIN IN RI AND
SOUTHEAST MASS.
IMPROVEMENT BEGINS TOWARDS EVENING AS WINDS REVERT WESTERLY AND
BECOME BLUSTERY...GUSTS DEVELOPING OVERNIGHT INTO FRIDAY THE
STRONGEST OF WHICH WILL LIKELY IMPACT SHORELINE TERMINALS. LOW- TO
MID-LEVEL CLOUDS FEW-SCT WILL LIKELY FILTER ACROSS THE TERMINALS.
KBOS TAF...HIGH CONFIDENCE IN TAF. LOWER CONFIDENCE WITH EXACT
TIMING OF IMPACTS. INITIAL SNOW ACCUMS OF AROUND A TENTH OR TWO IN
THE MORNING WILL WASH AWAY AS SNOW MIXES OVER TO RAIN DURING THE
MORNING HOURS.
KBDL TAF...HIGH CONFIDENCE IN TAF. MUCH OF THE ACTIVITY STAYS EAST
OF THE TERMINAL. EXPECTING JUST SOME FLURRIES TO A BRIEF LIGHT
SNOW SHOWER THAT WILL YIELD AROUND A TRACE OF SNOW ACCUM AT MOST.
OUTLOOK...FRIDAY NIGHT THROUGH MONDAY
FRIDAY NIGHT THROUGH SUNDAY MORNING...HIGH CONFIDENCE. VFR.
SUNDAY AFTERNOON THROUGH MONDAY...MODERATE CONFIDENCE. CIGS AND
VSBYS WILL LOWER TO MVFR IN DEVELOPING RAIN SUNDAY AFTERNOON AND
EVENING. PRECIPITATION MAY MIX WITH SNOW OR BECOME ALL SNOW IN
SOUTHERN NH AND PARTS OF NORTHERN MASS. IFR CONDITIONS POSSIBLE
SUNDAY NIGHT. PRECIPITATION ENDS BY MONDAY MORNING AND CONDITIONS
WILL IMPROVE TO VFR.
&&
.MARINE...
FORECASTER CONFIDENCE LEVELS...
LOW...LESS THAN 30 PERCENT.
MODERATE...30 TO 60 PERCENT.
HIGH...GREATER THAN 60 PERCENT.
NEAR TERM /THROUGH FRIDAY/...HIGH CONFIDENCE.
WILL SEE AN ENHANCEMENT OF FLOW AS AN AREA OF LOW PRES DEVELOPS S
OF NEW ENGLAND MIDDAY AND LIFTS NE INTO THE GULF OF MAINE BY
EVENING...GROWING STRONGER THROUGH ITS TRACK. WINDS VEERING E/SE
GRADUALLY TO S DURING THE DAY WILL AMPLIFY IN RESPONSE. SEAS
LIKELY TO BUILD TO 5 FEET OR GREATER BY MIDDAY...THUS SMALL-CRAFT
ADVISORIES ARE IN EFFECT.
ATTENDANT MIX OF RAIN AND SNOW INITIALLY CHANGING OVER TO ALL
RAIN THROUGH THE MORNING MAY YIELD VISIBILITY IMPACTS OVER THE
WATERS.
OVERNIGHT...COVERAGE OF SMALL-CRAFT ADVISORIES EXTENDS IN RESPONSE
TO WINDS BACKING OUT OF THE WEST BEHIND THE DEPARTING SYSTEM AND
BECOMING BLUSTERY WITH GUSTS UP TO 25 KTS. CONDITIONS CONTINUE
THROUGH FRIDAY. SEAS BUILDING OVER THE OUTER WATERS...5 TO 7 FEET.
OUTLOOK...FRIDAY NIGHT THROUGH MONDAY
MODERATE CONFIDENCE
FRIDAY NIGHT-SATURDAY...WEST TO SOUTHWEST WINDS MAY GUST NEAR 25
KNOTS. SEAS WILL SUBSIDE BELOW 5 FEET FRIDAY NIGHT...BUT THEN BUILD
ON SATURDAY TO 5-7 FEET ESPECIALLY ON THE OUTER WATERS. A SMALL
CRAFT ADVISORY MAY BE NEEDED FOR PARTS OF THE MASS AND RI WATERS.
SUNDAY...COASTAL LOW PRESSURE MOVES UP THE EAST COAST. VARIABLE
WINDS WILL BECOME NORTHEAST LATE SUNDAY AND THEN NORTHWEST MONDAY.
SPEEDS WILL BE AROUND 25 KNOTS...WHILE THE EXPOSED WATERS WILL SEE
SEAS BUILD TO 5 TO 7 FEET. SMALL CRAFT ADVISORY MAY BE NEEDED FOR
PARTS OF THE MASS AND RI WATERS.
&&
.BOX WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
MA...NONE.
NH...NONE.
RI...NONE.
MARINE...SMALL CRAFT ADVISORY FROM 6 PM THIS EVENING TO 2 AM EST FRIDAY
FOR ANZ231-232-251.
SMALL CRAFT ADVISORY FROM 6 PM THIS EVENING TO MIDNIGHT EST
TONIGHT FOR ANZ233-234.
SMALL CRAFT ADVISORY FROM 4 PM THIS AFTERNOON TO 2 AM EST
FRIDAY FOR ANZ235-237.
SMALL CRAFT ADVISORY FROM 1 PM THIS AFTERNOON TO 7 PM EST
FRIDAY FOR ANZ250-254>256.
&&
$$
SYNOPSIS...WTB/SIPPRELL
NEAR TERM...WTB/SIPPRELL
SHORT TERM...SIPPRELL
LONG TERM...WTB
AVIATION...WTB/SIPPRELL
MARINE...WTB/SIPPRELL
Area Forecast Discussion
National Weather Service Lincoln IL
958 AM CST Thu Dec 26 2013
.DISCUSSION...
ISSUED 958 AM CST Thu Dec 26 2013
Lingering area of altocumulus clouds about to exit the northeast
CWA, however another batch covers most of Iowa and is headed
southeast. Latest RAP model shows this spreading over the northern
half of the forecast area this afternoon. Recent zone/grid updates
mainly were done to reflect the latest cloud trends. Temperatures
currently on track and required little change other than the usual
hourly trend tweaks.
Geelhart
&&
.AVIATION...
ISSUED 559 AM CST Thu Dec 26 2013
VFR conditions should continue over the next 24 hours, as clippers
pass by just to the north of the area. Those weather disturbances
will bring mainly mid-level clouds over our terminal sites today
and tonight. No precipitation is expected, due to the amount of
dry air in the lowest levels of the atmosphere.
Winds will begin from the west early this morning, then become
southwest as high surface pressure passes by to the south of IL
and low pressure moves across the upper Midwest. Pressure
gradients will support wind speeds increasing into the 10-14kt
range today, which will maintain for much of the evening before
dropping below 10kt later tonight.
Shimon
&&
.PREV DISCUSSION...
ISSUED 207 AM CST Thu Dec 26 2013
SHORT TERM...Today through Saturday
Next short-wave embedded within the progressive northwesterly flow
pattern is evident on 08z/2am water vapor imagery over southern
Saskatchewan/northern Montana. As has been advertised for the past
few model runs, this wave will remain a bit further north than the
previous ones. This will keep any light snow or flurries well to
the north across Wisconsin and far northern Illinois today, while
central Illinois only sees a few clouds. Latest IR satellite imagery
shows skies clearing out in the wake of the previous disturbance:
however, plenty of cloud cover is poised just upstream ahead of
the next wave. Based on satellite trajectories, it appears clouds
will overspread much of the central and northern KILX CWA, while
skies remain mostly clear further south. Will be a fairly mild day
as well, with southerly winds allowing temps to rise a degree or
two higher than yesterday, mainly reaching the middle 30s.
Once short-wave passes tonight, upper flow will briefly become
zonal Friday into Saturday, leading to a considerable warming
trend. With 850mb temps progged to reach the 6 to 8C range, high
temps will likely climb well into the 40s and perhaps even the
lower 50s across the southeast CWA on Saturday.
LONG TERM...Sunday through Wednesday
The warmer weather will be short-lived however, as a significant
trough digs across the central/eastern CONUS early next week,
sending an Arctic cold front through central Illinois. Models
continue to suggest a band of post-frontal precip on Sunday. Given
the strength of the boundary and the approaching upper wave, will
mention a chance for snow as the front passes. Little or no
accumulation is expected, as system will have only limited
moisture to work with and will be moving rather fast. Once front
clears the area, sharply colder conditions are expected on Monday.
850mb temps drop to between -12 and -14C, resulting in highs temps
plunging into the teens.
Clipper system for early next week still remains in question, with
the 00z Dec 26 models exhibiting a 24-hour timing discrepancy.
ECMWF shows system skirting through central Illinois Monday/Monday
night, while the GFS delays it until Tuesday/Tuesday night. This
is a marked change for the ECMWF and given the fact that the GEM
more closely resembles the GFS solution, will stick with the GFS
in the extended. As a result, will continue with cold/dry weather
on Monday, then will bring snow chances into the area Tuesday and
Tuesday night. At this point, it appears greatest chance for
accumulating snow will mainly be confined to the northern half of
the CWA, but this will likely be fine-tuned as models gradually get
a better handle on the wave.
Barnes
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS JACKSON KY
940 AM EST THU DEC 26 2013
.UPDATE...
ISSUED AT 940 AM EST THU DEC 26 2013
A BAND OF SHALLOW LOW CLOUDS CONTINUES TO PUSH SOUTHEAST THIS MORNING
ACROSS EASTERN KENTUCKY. HOWEVER...THESE CLOUDS ARE ALREADY
DEVELOPING HOLES AND STARTING TO ERODE. THIS TREND SHOULD CONTINUE AS
WE HEAD TOWARDS SUNNY SKIES THIS AFTERNOON. WILL INCREASE SKY COVER
OVER THE NEXT FEW HOURS FOR THE SOUTHEAST...BEFORE GOING MAINLY SUNNY
BY THIS AFTERNOON. HAVE ALSO LOWERED RELATIVE HUMIDITY SLIGHTLY GIVEN
THE DECENT MIXING POTENTIAL UNDER THE SUNNY SKIES THIS AFTERNOON.
UPDATED FORECAST IS ALREADY OUT.
UPDATE ISSUED AT 715 AM EST THU DEC 26 2013
UPDATED THE GRIDS TO FINE TUNE TEMPERATURES...MAINLY MILDER...FOR THE
NEXT SEVERAL HOURS PER LATEST OBS AND TRENDS. DID ALSO ADJUST SKY
COVER TO BRING THE POST FRONTAL SC FURTHER SOUTH AND EAST FOR THE
FIRST PART OF THE MORNING...BUT STILL EXPECT THESE TO BE MOSTLY GONE
BY NOON. THE GRIDS HAVE BEEN SENT TO THE NDFD AND WEB SERVERS.
&&
.SHORT TERM...(TODAY THROUGH FRIDAY)
ISSUED AT 335 AM EST THU DEC 26 2013
07Z SFC ANALYSIS SHOWS A MOSTLY DRY COLD FRONT CROSSING EAST
KENTUCKY. THIS IS ACCOMPANIED BY A LOWER DECK OF CLOUDS AND SOME
RETURNS ON RADAR...MOSTLY VIRGA. LOWER CLOUDS...NEAR MVFR...TRAIL
THIS BOUNDARY AND WILL MOVE OVER THE NORTHERN TWO THIRDS OF THE CWA
INTO THE FIRST PART OF THE MORNING. THIS SHOULD KEEP TEMPERATURES
FROM FALLING MUCH FURTHER THROUGH THE AREA INTO DAWN. CURRENTLY THEY
VARY FROM THE UPPER 20S IN SOME VALLEYS TO THE MID 30S ON THE
RIDGES...WHILE DEWPOINTS ARE GENERALLY IN THE LOW AND MID 20S.
THE MODELS ARE IN GOOD ENOUGH AGREEMENT ALOFT THROUGH THE SHORT TERM
AS THEY ALL TAKE A SHARP SHORTWAVE NORTHEAST AND AWAY FROM THE OHIO
VALLEY TODAY. LATER...ANOTHER RIPPLE MOVES THROUGH THE BASE OF THE
RETREATING LARGE EAST CANADIAN TROUGH...PASSING HARMLESSLY THROUGH
THE AREA MIDDAY FRIDAY. HEIGHTS WILL THEN RISE OVER THE STATE AHEAD
OF A BROAD AND UNCONSOLIDATED AREA OF LOWER ONES ASSOCIATED WITH THE
POOLING ENERGY OVER SOUTH CENTRAL TEXAS. THE MODELS ARE HAVING THE
MOST DIFFICULTIES WITH THIS FEATURE AS THE NAM IS OUT OF STEP WITH
THE OTHERS IN KEEPING THE RESULTANT MID LEVEL LOW WEAKER AND A NOTCH
FURTHER EAST THAN CONSENSUS. THESE DIFFERENCES WILL AFFECT THE
FORECAST OVER THE WEEKEND...BEYOND THE SHORT TERM SO THE NAM12 WAS
PRIMARILY USED...ALONG WITH THE LATEST HRRR FOR THE NEAR TERM WX...
TO GUIDE THIS PART OF THE FORECAST.
SENSIBLE WEATHER WILL FEATURE A FLEETING CHANCE OF MAINLY FLURRIES
PASSING THROUGH FAR EAST KENTUCKY OVER THE NEXT COUPLE OF HOURS.
OTHERWISE...IT WILL BE A DRY AND QUIET FORECAST TO END THE WORK WEEK
AS SFC HIGH PRESSURE IS BUFFETED BY PASSING MID LEVEL WAVES AND
THEIR SFC REFLECTIONS TO THE NORTH OF THE AREA. THIS WILL BE NOTED
MAINLY IN TIMES OF MID AND HIGH CLOUDS BRUSHING PAST THE CWA.
TEMPERATURES THROUGH EAST KENTUCKY WILL BE SEASONABLY NEAR NORMAL
WHILE WE AWAIT THE SOUTHERN DEVELOPMENT FOR A SHOT AT A RETURN OF
PCPN LATER IN THE WEEKEND.
FOLLOWED THE CONSSHORT AND ITS BC PARTNER FOR T...TD...AND WINDS
THROUGH 12Z FRIDAY WITH SOME BLENDING IN WITH THE DIURNAL FROM THE
NAM12 FOR HOURLY TEMPS. OTHERWISE...THE CONSALL WAS USED AS A
STARTING POINT. DID ADD IN SOME MINOR RIDGE AND VALLEY TEMPERATURE
DIFFERENCES TONIGHT WHILE KEEPING POPS IN THE LOW SINGLE DIGITS AT
BEST...IN LINE WITH MOS...OUTSIDE OF THE NEXT FEW HOURS IN THE FAR
EAST.
.LONG TERM...(FRIDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 330 AM EST THU DEC 26 2013
THE BEGINNING OF THE EXTENDED PERIOD /12Z SATURDAY/ WILL HOST ZONAL
FLOW ALOFT AND SURFACE HIGH PRESSURE...MAKING FOR CLEAR SKIES IN THE
MORNING. HOWEVER...THIS SET UP WILL BE SHORT LIVED...AS TWO SYSTEMS
WILL BEGIN TO INTERACT ON EASTERN KY OVER THE NEXT 24 TO 36 HOURS.
THE FIRST OF THESE SYSTEMS...A STRONG UPPER LEVEL SHORTWAVE ACROSS
THE SOUTHERN PLAINS MOVING SLOWLY NEWARD. A SURFACE LOW PRESSURE
SYSTEM WILL DEVELOP SLIGHTLY EASTWARD OF THE UPPER TROUGH...PULLING
IN MOISTURE OFF THE GULF OF MEXICO ACROSS THE SOUTHERN STATES AND
THEN INTO SOUTHERN AND EASTERN KY SATURDAY NIGHT/SUNDAY MORNING. THE
SECOND SHORTWAVE WILL BE SLIGHTLY WEAKER...MOVING IN JUST BEHIND AND
NORTH OF THE ORIGINAL WAVE. THIS WILL PUSH A COLD FRONT ACROSS
KY FROM THE NW MONDAY EVENING/NIGHT. OF THE TWO...EXPECT THE BEST
PRECIP CHANCES AND QPF TO COME FROM THE FIRST SYSTEM...BEGINNING
RIGHT BEFORE 6Z SUNDAY AND CONTINUING THROUGH SUNDAY
AFTERNOON/EVENING. THEN THE SECOND WAVE OF MOISTURE BEGINS TO HIT KY
FROM THE NORTH AND WEST SUNDAY NIGHT INTO MONDAY. THIS TIME THE
PRECIP WILL BE LIGHTER AND SCATTERED IN NATURE.
UNFORTUNATELY...MODELS ARE STILL NOT COMPLETELY AGREEING ON THEIR
TIMING AND SET UP...SO WILL CONTINUE WITH THE ALLBLEND OUTPUT AT
THIS TIME FOR POPS.
WITH A WARM PULL FROM THE SOUTH AHEAD OF THESE TWO SYSTEMS...TEMPS
WILL RISE TO ABOVE NORMALS SATURDAY AND SUNDAY /UPPER 40S AND LOW
50S/. HOWEVER...ONCE THE COLD FRONT ACCOMPANYING THE SECOND SYSTEM
PUSHES THROUGH...IT WILL USHER IN COLDER AIR FROM THE NW.
TEMPERATURE DIFFERENCES COULD BE AS MUCH AS 15 DEGREES COOLER FROM
SUNDAY INTO MONDAY...FALLING NEAR FREEZING FOR HIGHS. THIS
TEMPERATURE DROP WILL BE WHAT GOVERNS RAIN VS. SNOW WITH THIS SECOND
SYSTEM. AT PRESENT...HAVE ALL RAIN IN FORECAST UNTIL AROUND
MIDNIGHT...AT WHICH POINT A RAIN AND SNOW MIX WILL BE
POSSIBLE...BEFORE TEMPS DROP ENOUGH TO GOVERN ALL SNOW BY 9Z.
PROLONGED TIME PERIOD FOR WHICH ACCUMULATIONS COULD OCCUR COMPARED
TO PREVIOUS FORECAST...BUT DID DROP AMOUNTS SLIGHTLY IN THE WESTERN
HALF OF THE CWA. ANYWHERE BETWEEN A DUSTING TO A COUPLE TENTHS OF AN
INCH WILL BE POSSIBLE ACROSS MUCH THE CWA...WITH THE HIGHER TERRAIN
EXPECTED TO SEE A BIT MORE...BETWEEN A HALF AN INCH TO ONE INCH.
OBVIOUSLY THIS SYSTEM IS FAIRLY FAR OUT IN THE FORECAST...SO EXPECT
THESE TOTALS TO CONTINUE TO CHANGE AS WE GET CLOSER TO THE ONSET.
WITH A TROUGHING PATTERN SETTING UP ACROSS THE EASTERN U.S...COULD
SEE SEVERAL MORE SHORTWAVES MOVE THROUGH THE TROUGH OVER THE FEW
DAYS FOLLOWING. AT THIS TIME...MODEL SOLUTIONS ARE KEEPING ANY
MOISTURE RELATED TO THESE SHORTWAVES AWAY FROM EASTERN KY. THAT
BEING SAID...TUESDAY NIGHT/WEDNESDAY MORNING WILL BE A TIME FRAME TO
WATCH...AS ANY VARIATIONS SOUTHWARD FROM WHERE THE BLENDED RUN
PLACES THE SYSTEM...KJKL COULD SEE PRECIPITATION.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z FRIDAY MORNING)
ISSUED AT 655 AM EST THU DEC 26 2013
MAINLY VFR CONDITIONS WILL PREVAIL THROUGH THE FORECAST PERIOD.
HOWEVER...THE TAF SITES WILL SEE A PERIOD OF LOW AND MID LEVEL CLOUD
COVER FOR THE FIRST PART OF THE MORNING. LOWEST POTENTIAL CIGS WILL
BE DOWN TO AROUND 3K FT NEAR AND NORTH OF KJKL ALONG WITH A BRIEF
PERIOD OF MVFR POSSIBLE. WINDS WILL BE FROM THE WEST AT 10 TO 15 KTS
TO START THE DAY BEFORE SETTLING A BIT TO BETWEEN 5 AND 10 KTS
LATER IN THE DAY.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...KAS
SHORT TERM...GREIF
LONG TERM...JMW
AVIATION...GREIF
AREA FORECAST DISCUSSION...UPDATED
NWS JACKSON KY
715 AM EST THU DEC 26 2013
.UPDATE...
ISSUED AT 715 AM EST THU DEC 26 2013
UPDATED THE GRIDS TO FINE TUNE TEMPERATURES...MAINLY MILDER...FOR THE
NEXT SEVERAL HOURS PER LATEST OBS AND TRENDS. DID ALSO ADJUST SKY
COVER TO BRING THE POST FRONTAL SC FURTHER SOUTH AND EAST FOR THE
FIRST PART OF THE MORNING...BUT STILL EXPECT THESE TO BE MOSTLY GONE
BY NOON. THE GRIDS HAVE BEEN SENT TO THE NDFD AND WEB SERVERS.
&&
.SHORT TERM...(TODAY THROUGH FRIDAY)
ISSUED AT 335 AM EST THU DEC 26 2013
07Z SFC ANALYSIS SHOWS A MOSTLY DRY COLD FRONT CROSSING EAST
KENTUCKY. THIS IS ACCOMPANIED BY A LOWER DECK OF CLOUDS AND SOME
RETURNS ON RADAR...MOSTLY VIRGA. LOWER CLOUDS...NEAR MVFR...TRAIL
THIS BOUNDARY AND WILL MOVE OVER THE NORTHERN TWO THIRDS OF THE CWA
INTO THE FIRST PART OF THE MORNING. THIS SHOULD KEEP TEMPERATURES
FROM FALLING MUCH FURTHER THROUGH THE AREA INTO DAWN. CURRENTLY THEY
VARY FROM THE UPPER 20S IN SOME VALLEYS TO THE MID 30S ON THE
RIDGES...WHILE DEWPOINTS ARE GENERALLY IN THE LOW AND MID 20S.
THE MODELS ARE IN GOOD ENOUGH AGREEMENT ALOFT THROUGH THE SHORT TERM
AS THEY ALL TAKE A SHARP SHORTWAVE NORTHEAST AND AWAY FROM THE OHIO
VALLEY TODAY. LATER...ANOTHER RIPPLE MOVES THROUGH THE BASE OF THE
RETREATING LARGE EAST CANADIAN TROUGH...PASSING HARMLESSLY THROUGH
THE AREA MIDDAY FRIDAY. HEIGHTS WILL THEN RISE OVER THE STATE AHEAD
OF A BROAD AND UNCONSOLIDATED AREA OF LOWER ONES ASSOCIATED WITH THE
POOLING ENERGY OVER SOUTH CENTRAL TEXAS. THE MODELS ARE HAVING THE
MOST DIFFICULTIES WITH THIS FEATURE AS THE NAM IS OUT OF STEP WITH
THE OTHERS IN KEEPING THE RESULTANT MID LEVEL LOW WEAKER AND A NOTCH
FURTHER EAST THAN CONSENSUS. THESE DIFFERENCES WILL AFFECT THE
FORECAST OVER THE WEEKEND...BEYOND THE SHORT TERM SO THE NAM12 WAS
PRIMARILY USED...ALONG WITH THE LATEST HRRR FOR THE NEAR TERM WX...
TO GUIDE THIS PART OF THE FORECAST.
SENSIBLE WEATHER WILL FEATURE A FLEETING CHANCE OF MAINLY FLURRIES
PASSING THROUGH FAR EAST KENTUCKY OVER THE NEXT COUPLE OF HOURS.
OTHERWISE...IT WILL BE A DRY AND QUIET FORECAST TO END THE WORK WEEK
AS SFC HIGH PRESSURE IS BUFFETED BY PASSING MID LEVEL WAVES AND
THEIR SFC REFLECTIONS TO THE NORTH OF THE AREA. THIS WILL BE NOTED
MAINLY IN TIMES OF MID AND HIGH CLOUDS BRUSHING PAST THE CWA.
TEMPERATURES THROUGH EAST KENTUCKY WILL BE SEASONABLY NEAR NORMAL
WHILE WE AWAIT THE SOUTHERN DEVELOPMENT FOR A SHOT AT A RETURN OF
PCPN LATER IN THE WEEKEND.
FOLLOWED THE CONSSHORT AND ITS BC PARTNER FOR T...TD...AND WINDS
THROUGH 12Z FRIDAY WITH SOME BLENDING IN WITH THE DIURNAL FROM THE
NAM12 FOR HOURLY TEMPS. OTHERWISE...THE CONSALL WAS USED AS A
STARTING POINT. DID ADD IN SOME MINOR RIDGE AND VALLEY TEMPERATURE
DIFFERENCES TONIGHT WHILE KEEPING POPS IN THE LOW SINGLE DIGITS AT
BEST...IN LINE WITH MOS...OUTSIDE OF THE NEXT FEW HOURS IN THE FAR
EAST.
.LONG TERM...(FRIDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 330 AM EST THU DEC 26 2013
THE BEGINNING OF THE EXTENDED PERIOD /12Z SATURDAY/ WILL HOST ZONAL
FLOW ALOFT AND SURFACE HIGH PRESSURE...MAKING FOR CLEAR SKIES IN THE
MORNING. HOWEVER...THIS SET UP WILL BE SHORT LIVED...AS TWO SYSTEMS
WILL BEGIN TO INTERACT ON EASTERN KY OVER THE NEXT 24 TO 36 HOURS.
THE FIRST OF THESE SYSTEMS...A STRONG UPPER LEVEL SHORTWAVE ACROSS
THE SOUTHERN PLAINS MOVING SLOWLY NEWARD. A SURFACE LOW PRESSURE
SYSTEM WILL DEVELOP SLIGHTLY EASTWARD OF THE UPPER TROUGH...PULLING
IN MOISTURE OFF THE GULF OF MEXICO ACROSS THE SOUTHERN STATES AND
THEN INTO SOUTHERN AND EASTERN KY SATURDAY NIGHT/SUNDAY MORNING. THE
SECOND SHORTWAVE WILL BE SLIGHTLY WEAKER...MOVING IN JUST BEHIND AND
NORTH OF THE ORIGINAL WAVE. THIS WILL PUSH A COLD FRONT ACROSS
KY FROM THE NW MONDAY EVENING/NIGHT. OF THE TWO...EXPECT THE BEST
PRECIP CHANCES AND QPF TO COME FROM THE FIRST SYSTEM...BEGINNING
RIGHT BEFORE 6Z SUNDAY AND CONTINUING THROUGH SUNDAY
AFTERNOON/EVENING. THEN THE SECOND WAVE OF MOISTURE BEGINS TO HIT KY
FROM THE NORTH AND WEST SUNDAY NIGHT INTO MONDAY. THIS TIME THE
PRECIP WILL BE LIGHTER AND SCATTERED IN NATURE.
UNFORTUNATELY...MODELS ARE STILL NOT COMPLETELY AGREEING ON THEIR
TIMING AND SET UP...SO WILL CONTINUE WITH THE ALLBLEND OUTPUT AT
THIS TIME FOR POPS.
WITH A WARM PULL FROM THE SOUTH AHEAD OF THESE TWO SYSTEMS...TEMPS
WILL RISE TO ABOVE NORMALS SATURDAY AND SUNDAY /UPPER 40S AND LOW
50S/. HOWEVER...ONCE THE COLD FRONT ACCOMPANYING THE SECOND SYSTEM
PUSHES THROUGH...IT WILL USHER IN COLDER AIR FROM THE NW.
TEMPERATURE DIFFERENCES COULD BE AS MUCH AS 15 DEGREES COOLER FROM
SUNDAY INTO MONDAY...FALLING NEAR FREEZING FOR HIGHS. THIS
TEMPERATURE DROP WILL BE WHAT GOVERNS RAIN VS. SNOW WITH THIS SECOND
SYSTEM. AT PRESENT...HAVE ALL RAIN IN FORECAST UNTIL AROUND
MIDNIGHT...AT WHICH POINT A RAIN AND SNOW MIX WILL BE
POSSIBLE...BEFORE TEMPS DROP ENOUGH TO GOVERN ALL SNOW BY 9Z.
PROLONGED TIME PERIOD FOR WHICH ACCUMULATIONS COULD OCCUR COMPARED
TO PREVIOUS FORECAST...BUT DID DROP AMOUNTS SLIGHTLY IN THE WESTERN
HALF OF THE CWA. ANYWHERE BETWEEN A DUSTING TO A COUPLE TENTHS OF AN
INCH WILL BE POSSIBLE ACROSS MUCH THE CWA...WITH THE HIGHER TERRAIN
EXPECTED TO SEE A BIT MORE...BETWEEN A HALF AN INCH TO ONE INCH.
OBVIOUSLY THIS SYSTEM IS FAIRLY FAR OUT IN THE FORECAST...SO EXPECT
THESE TOTALS TO CONTINUE TO CHANGE AS WE GET CLOSER TO THE ONSET.
WITH A TROUGHING PATTERN SETTING UP ACROSS THE EASTERN U.S...COULD
SEE SEVERAL MORE SHORTWAVES MOVE THROUGH THE TROUGH OVER THE FEW
DAYS FOLLOWING. AT THIS TIME...MODEL SOLUTIONS ARE KEEPING ANY
MOISTURE RELATED TO THESE SHORTWAVES AWAY FROM EASTERN KY. THAT
BEING SAID...TUESDAY NIGHT/WEDNESDAY MORNING WILL BE A TIME FRAME TO
WATCH...AS ANY VARIATIONS SOUTHWARD FROM WHERE THE BLENDED RUN
PLACES THE SYSTEM...KJKL COULD SEE PRECIPITATION.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z FRIDAY MORNING)
ISSUED AT 655 AM EST THU DEC 26 2013
MAINLY VFR CONDITIONS WILL PREVAIL THROUGH THE FORECAST PERIOD.
HOWEVER...THE TAF SITES WILL SEE A PERIOD OF LOW AND MID LEVEL CLOUD
COVER FOR THE FIRST PART OF THE MORNING. LOWEST POTENTIAL CIGS WILL
BE DOWN TO AROUND 3K FT NEAR AND NORTH OF KJKL ALONG WITH A BRIEF
PERIOD OF MVFR POSSIBLE. WINDS WILL BE FROM THE WEST AT 10 TO 15 KTS
TO START THE DAY BEFORE SETTLING A BIT TO BETWEEN 5 AND 10 KTS
LATER IN THE DAY.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...GREIF
SHORT TERM...GREIF
LONG TERM...JMW
AVIATION...GREIF
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
501 AM CST THU DEC 26 2013
.UPDATE...
12Z AVIATION DISCUSSION ADDED BELOW.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 348 AM CST THU DEC 26 2013
WE CONTINUE TO FIND OURSELVES WITHIN MOIST CYCLONIC NORTHWEST FLOW
THIS MORNING...WITH CLOUDS AND BOUTS OF FLURRIES/LIGHT SNOW
CONTINUING TO DOMINATE THE NRN PLAINS AND UPPER MS VALLEY. THE TWO
FEATURES OF INTEREST THIS MORNING ARE THE STRONG UPPER WAVE
CURRENTLY VISIBLE IN WATER VAPOR IMAGERY MOVING ACROSS THE DAKOTAS
AND A WARM/STATIONARY FRONT THAT IS MORE OR LESS LINED UP WITH THE
MN RIVER FROM WC INTO SE MN. CURRENT THINKING IS THAT THIS FRONT
WILL ACT AS A FOCUS FOR A HEAVIER BAND OF PRECIP FROM ABOUT 15Z-21Z
TODAY. BASED POP/QPF GRIDS FOR THIS BAND OF SNOW ON THE GFS AND
SREF...WHICH RESULTED IN THE BAND COMING DOWN BETWEEN I-94 AND THE
MN RIVER. THOUGH CATEGORICAL POPS HAVE BEEN RETAINED...THE HRRR AND
HOPWRF MEMBERS ALONG THE THE NAM/GEM SHOW VERY LITTLE SNOW COMING
DOWN ALONG THIS FRONT...INSTEAD TAKING MOST OF IT ACROSS NRN MN WITH
THE BRUNT OF THE FORCING WITH THE UPPER WAVE...SO WOULD NOT BE
SURPRISED IF THESE POPS END UP BEING OVERDONE. THIS LOOKS TO BE A
FAIRLY TRANSIENT FEATURE WHICH MEANS IT IS ONLY EXPECTED TO BRING A
DUSTING TO ONE INCH OF SNOW. FOR THIS AFTERNOON INTO TONIGHT...WE
FINALLY GET ON THE BACKSIDE OF ALL OF THE PASSING SHORTWAVES IN NW
FLOW...WHICH MEANS WE WILL FINALLY SHUT OFF THE SNOW MACHINES AND
WORK A CLEARING OF THE LOW CLOUDS AT LEAST FROM WEST TO EAST.
FOR TEMPERATURES...BASED ON THE WARMER TEMPERATES SEEN
YESTERDAY...FAVORED HIGHS TODAY TOWARD THE HIGHER END OF
GUIDANCE...ESPECIALLY SOUTH OF THE BOUNDARY. FOR TONIGHT...WINDS
WILL START TO INCREASE OUT OF THE SW AND WILL START TO ADVECT IN A
MILDER PACIFIC AIRMASS. THE WAA WILL BE TEMPERED A BIT BY AT LEAST A
PARTIAL CLEARING OF THE SKIES AND ATTENDANT RADIATIONAL
COOLING...BUT LOOKS TO BE ENOUGH TO SAFELY KEEP EVERYONE ABOVE ZERO
FOR A SECOND NIGHT IN A ROW.
.LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 348 AM CST THU DEC 26 2013
LONG TERM TRENDS CONTINUE TO REMAIN ON TRACK AT LEAST EARLY IN THE
PERIOD. STILL SEE THE POTENTIAL OF AT LEAST GROUND BLIZZARD
CONDITIONS DEVELOPING BY SATURDAY NIGHT ACROSS MUCH OF WESTERN
INTO SOUTHERN MINNESOTA. STILL RATHER MILD BEFORE THEN.
SHOULD SEE SOME HIGH TEMPERATURES WARMING TO AROUND 40 OR SO IN
SOUTHWEST MINNESOTA ON FRIDAY. VERY MILD PACIFIC AIR RIDES EAST
INTO THE AREA FRIDAY...WITH 85H TEMPERATURES WARMING TO 8-10C BY
FRIDAY EVENING OVER THE SOUTHWEST. MINIMAL MIX WITH THIS SHOULD
YIELD THE WARMER TEMPERATURES...WITH LOWER AND SOME MIDDLE 30S TO
THE EAST. SHOULD REMAIN RATHER WARM FRIDAY NIGHT AHEAD OF THE
ARCTIC FRONT. LOWS WILL BE DETERMINED BY WINDS OVERNIGHT. ANY
DECOUPLING OF THE BL WILL STILL GENERATE SOME COOL READINGS.
OVERALL...MODELS HAVE TRENDED A LITTLE WETTER WITH THE TROUGH ASSOCIATED
WITH THE ARCTIC COLD FRONT THAT WILL DIVE SOUTH OVER THE AREA
SATURDAY NIGHT. IT DOES APPEAR THERE WILL BE THE POTENTIAL OF AT
LEAST A PERIOD OF SNOW ASSOCIATED WITH THIS FEATURE AS IT MOVES
THROUGH. DID USE POTWX AND INTRODUCED SOME FREEZING DRIZZLE AT
LEAST INITIALLY AS THE FRONT ARRIVES. THIS...ALONG WITH SOME OF
THE MORE MILD TEMPERATURES MAY PROHIBIT SIGNIFICANT BLOWING SNOW
DEVELOPMENT FOR A TIME...BUT BELIEVE ANY POTENTIAL CRUST ON THE
SNOW WILL BE ERODED BY THE STRONG WINDS DEVELOPING AS THE COLD AIR
ARRIVES. BUFKIT PROFILES STILL INDICATE WIND GUSTS AROUND 35 KTS PLUS
LIKELY SATURDAY NIGHT...ESPECIALLY ALONG AND SOUTH OF THE
MINNESOTA RIVER VALLEY. THIS SHOULD BE ENOUGH TO GENERATE THE MORE
WIDESPREAD BLOWING SNOW CONDITIONS. WILL HAVE TO MONITOR THIS
TREND WITH HEADLINES A DEFINITE POSSIBILITY.
VERY COLD CONDITIONS ENSUE FOR MONDAY AND TUESDAY. MONDAY MORNING
APPEARS TO BE LIKELY THE COLDEST FOR THE CWA...WITH TUESDAY
MORNING A GOOD SECOND...ESPECIALLY TO THE EAST. MUCH OF THE AREA
MAY STAY BELOW ZERO ON MONDAY. SURFACE WINDS SHOULD BE
LIGHT...BUT MAY STILL PRODUCE WIND CHILLS CLOSE TO WARNING
CRITERIA OVER THE NORTHERN CWA SUNDAY NIGHT/MONDAY MORNING. TIMING
OF ANY ADDITIONAL SNOW EVENTS DIFFICULT...ALTHOUGH THE GFS AND GEM
CONTINUE TO TRACK A SHOT OF LIGHT SNOW OVER SOUTHERN MINNESOTA
MONDAY NIGHT INTO EARLY TUESDAY. HAVE ENTERED A CHANCE FOR SNOW
WITH THIS FOR NOW. SOME MINOR TEMPERATURE MODERATION LATER IN THE
PERIOD COULD YIELD MORE LIGHT SNOW...BUT DIFFICULT TO LATCH ONTO
ANYTHING SIGNIFICANT AT THIS TIME.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z FRIDAY MORNING)
ISSUED AT 447 AM CST THU DEC 26 2013
WARM FRONT RIGHT NOW IS JUST NE OF THE MN RIVER. BETWEEN THE WARM
FRONT AND I-94...A CLEARING HAS DEVELOPED...WHICH WILL PLACE
AXN/STC/MSP ON THE EDGE OF MVFR CIGS UNTIL ANOTHER LIGHT SNOW
BURST ARRIVES LATER THIS MORNING. NOT MUCH WAS CHANGED WITH
TIMING OF THE SNOW FROM EXISTING TAFS...AS IT MATCHES UP WELL WITH
THE SREF PROBS. EXPECT MVFR/TEMPO IFR VIS SNOW TO MOVE THROUGH MN
TERMINALS...BUT MAY SLIDE SOUTH OF WIS TERMINALS. NOT COMPLETELY
SOLD ON THIS SNOW PANNING OUT AS THE HRRR AND HOPWRF CONTINUE TO
STRUGGLE TO BRING MUCH SNOW DOWN ALONG THE WARM FRONT OVER SRN MN.
BEHIND THE SNOW...WE WILL REMAIN MOIST IN THE LOW LEVELS...SO
EXPECT LOWER CIGS TO HANG AROUND UNTIL THE FRONT BEGINS TO HEAD
EAST IN THE EVENING...BRINGING VFR CIGS IN ITS WAKE.
KMSP...ASSUMING THE SREF IS RIGHT...CONFIDENCE IS HIGH IN CURRENT
SNOW TIMING...BUT SOME OF THE SHORT TERM GUIDANCE SHOWS THE
AIRPORT REMAINING DRY...SO THERE IS THE POTENTIAL WE DON/T SEE
MUCH MORE THAN SOME FLURRIES LATE MORNING. CIG FORECAST WILL BE
TOUGH AS EDGE OF MVFR CIGS WILL LIKELY REMAIN JUST NORTHEAST OF
THE FIELD...AND MAY TRY TO BUILD BACK SOUTH AHEAD OF THE
SNOW...SO WILL HAVE TO WATCH THAT AS WELL. WINDS WILL REMAIN
VARIABLE AND UNDER 7 KTS THROUGH TONIGHT. CONFIDENCE IN CIGS THIS
AFTERNOON IS LOW...AS IT MAY JUST STAY VFR...BUT EVENTUALLY BOTH
THE GFS AND NAM SHOW ATMO BELOW 20K FT DRYING OUT PRETTY GOOD
TONIGHT.
/OUTLOOK FOR KMSP/
FRI...VFR. WINDS SW 5-10 KTS.
SAT...VFR. CHC MVFR/-SN LATE. WINDS SW 5-10 KTS BCMG NW 20G30KTS.
SUN...VFR. WINDS NW 10 KTS.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
&&
$$
SHORT TERM...MPG
LONG TERM...DWE
AVIATION...MPG
AREA FORECAST DISCUSSION
NWS NORTH PLATTE NE
659 AM CST THU DEC 26 2013
.SYNOPSIS...
ISSUED AT 343 AM CST THU DEC 26 2013
NEXT IN THE SERIES OF UPPER PV ANOMALIES...CURRENTLY LOCATED OVER
ERN MT...WILL DROP ACROSS THE NORTHERN PLAINS TODAY...ORIGINATING
FROM THE NORTHERN PACIFIC REGION INSTEAD OF THE ARCTIC. AHEAD OF THE
FEATURES WESTERLY OR SOUTHWESTERLY COMPONENT TO THE WINDS JUST OFF
THE SURFACE IS BRINGING WARMER AIR TO THE WESTERN HIGH PLAINS AND
CONTINUING INTO THE MORNING HOURS. AT THE HEMISPHERIC SCALE...A
PROGRESSIVE PATTERN REMAINS ACROSS THE NORTHERN HEMISPHERE WITH AN
UPPER LOW MOVING QUICKLY INTO THE ERN U.S. AND HIGH PRESSURE ALOFT
BUILDING INTO THE PAC NW.
&&
.UPDATE...
ISSUED AT 659 AM CST THU DEC 26 2013
UPDATED MAX TEMPS FOR THIS AFTERNOON BASED ON EARLY MORNING DATA
RECEIVED FROM THE KLBF RADIOSONDE. TEMPS JUST OFF THE SURFACE
WARMER THAN 26.00 MODELS ANTICIPATED AND WHEN MIXED UNDER FULL SUN
WOULD SUPPORT UPPER 50S FOR SOUTHWEST NEB. HOWEVER...STILL HAVE
MID AND UPPER LEVEL CLOUDS TO CONTENT WITH WHICH WILL LIMIT
HEATING POTENTIAL FOR A PORTION OF THE DAY. HAVE TAKEN A MIDDLE
GROUND FROM WHERE MAX TEMPS WERE IN THE PREV FCST TO MAX POTENTIAL AS
A COMPROMISE. REMAINDER OF THE FORECAST PRETTY MUCH LEFT AS IT WAS.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 343 AM CST THU DEC 26 2013
PREVIOUSLY MENTIONED PV ANOMALY DIVES SOUTHEAST ACROSS THE NORTHERN
PLAINS WHICH WILL DRIVE A WEAK COLD FRONT ACROSS THE AREA LATER IN
THE DAY. BRIEF WARM AIR ADVECTION THIS MORNING WILL ALLOW TEMPS TO
BE WARMER THAN YESTERDAY AND ALTHOUGH WINDS WILL BECOME NWRLY BY
AFTERNOON...COOLER AIR LAGS THE WEAK FRONT SOMEWHAT AND IS WEAK
ESPECIALLY IN THE WEST. IN ADDITION...JET DYNAMICS ARE NOT FAVORABLE
FOR LARGE SCALE ASCENT AND DRIER AIR IN THE MID LEVELS ACCOMPANYING
THE WARMER AIR AHEAD OF THE SYSTEM WOULD PRECLUDE ANY PRECIP
DEVELOPMENT ANYWAY. RESULT IS SOME MID AND HIGH CLOUDS BY LATE
MORNING INTO THE AFTERNOON...COVERAGE SHOULD NOT LIMIT MAX TEMPS
FROM REACHING LEVELS 10 TO 12 DEGREES ABOVE AVERAGE IN THE
SOUTH...BUT ONLY A FEW DEGREES ABOVE AVE IN THE NORTH. STILL SOME
SNOW COVER ACROSS SHERIDAN AND WESTERN CHERRY COUNTIES SO SOME
INFLUENCE ON TEMPS THERE...BUT OTHERWISE MAINLY OPEN GROUND. NAM
TEMPS ARE HEAVILY INFLUENCED STILL BY HAVING TOO MUCH SNOW COVER
ANALYZED.
UPPER RIDGE BUILD ACROSS THE WEST OVER NIGHT WITH GOOD SUBSIDENCE
CLEARING CLOUDS. WILL ALLOW FOR GOOD RADIATIONAL COOLING BUT LOW
TEMPS STILL ABOVE AVE FOR THIS TIME OF YEAR.
.LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 343 AM CST THU DEC 26 2013
FORECAST FOCUS FOR FRIDAY INTO SATURDAY IS TEMPERATURES. THE THERMAL
RIDGE ALOFT KEEPS TEMPERATURES ABNORMALLY WARM...WITH 850MB
TEMPERATURES AT 9C TO 11C FRIDAY AND FRIDAY NIGHT. MODELS
/ESPECIALLY THE NAM/ ARE HAVING SOME ISSUES WITH THE SNOW
COVER...AND THUS THE AMOUNT OF MIXING/WARMING THAT WILL BE REALIZED
ON FRIDAY. THERE MAY BE SOME HIGH CLOUDS BUT NOT EXPECTING ENOUGH TO
MAKE A HUGE IMPACT ON HIGHS. WILL ALSO HAVE BREEZY WESTERLY WINDS TO
ENHANCE THE DOWNSLOPE WARMING EFFECT...AND HELP WARM TEMPERATURES TO
THE UPPER 40S AND 50S. LOWS FRIDAY NIGHT SHOULD STAY FAIRLY MILD AS
THE WINDS STAY UP AND CLOUDS INCREASE DUE TO AN INCOMING FRONTAL
BOUNDARY.
AN UPPER LEVEL TROUGH WILL PASS ACROSS THE PLAINS SATURDAY NIGHT
INTO SUNDAY. MODEL SOLUTIONS ARE IN GOOD AGREEMENT THAT IMPACT
LOCALLY WILL BE MINIMAL...WITH THE PRIMARY CONCERNS BEING A CHANGE
IN TEMPERATURES.
THERE ARE TWO PRIMARY PV ANOMALIES THAT WILL MOVE THROUGH THE
TROUGH...THE FIRST ORIGINATES OVER THE YUKON AND NORTHWEST
TERRITORIES WHICH THEN DIGS SOUTHWARD AND MOVES THROUGH THE DAKOTAS
ON SUNDAY. THE SECOND IS THE SYSTEM CURRENTLY OUT OVER THE NORTHERN
PACIFIC WHICH WILL MOVE EAST AND DAMPEN THE RIDGE AND MOVE INTO THE
PACIFIC NORTHWEST FRIDAY THEN PROGRESS THROUGH THE TROUGH WITH THE
MAIN PART OF THE PV ANOMALY STAYING WELL SOUTH OF THE FORECAST
AREA...THROUGH THE FOUR CORNERS AND INTO THE SOUTHERN PLAINS. THESE
TWO BITS OF ENERGY WILL NOT PHASE TOGETHER SO UPWARD FORCING WILL
NOT BE GREAT IN THE LOCAL AREA AS THESE SYSTEMS PASS. DID KEEP LOW
CHANCES ACROSS NORTHERN NEBRASKA INTO THE PANHANDLE ON SATURDAY
AFTERNOON AND SATURDAY NIGHT AS SOUNDINGS AND CROSS SECTIONS DO SHOW
A BIT OF LIFT IN THE SATURATED LAYER...WHICH IS FAIRLY LOW...BELOW
700MB. AS THE MOISTURE WON/T BE DEEP...A CONCERN IS PRECIPITATION
TYPE WITH THE STRONG COLD AIR ADVECTION DURING THE DAY SATURDAY.
AHEAD OF THE FRONT AT 12Z SATURDAY...MODEL SOLUTIONS ARE SHOWING
850MB TEMPERATURES OF 10C TO 12C AND BY 00Z SUNDAY RANGE FROM -13C
IN THE NORTHERN PANHANDLE TO AROUND 0C OVER SOUTH CENTRAL NEBRASKA.
BELIEVE WITH THIS DRASTIC MOVEMENT OF COLD AIR...WILL LIKELY SEE A
NON-DIURNAL CURVE FOR TEMPERATURES ON SATURDAY. AREAS ACROSS THE
NORTH WILL PROBABLY ONLY RISE INTO THE MID TO UPPER 30S AND LOW
40S...WHILE ACROSS THE SOUTHERN PART WILL BE MUCH WARMER. CURRENTLY
HAVE UPPER 40S AND LOW 50S IN THE FORECAST THINKING THERE WILL BE
GOOD MIXING RIGHT ALONG AND AHEAD OF THE FRONT TO BRING WARMER
TEMPERATURES TO THESE AREAS. THE COLD AIR LOOKS TO MOVE IN FAIRLY
UNIFORMLY ACCORDING TO FORECAST SOUNDINGS SO A GOOD WARM LAYER DOES
NOT SET UP...WHICH MEANS PRECIPITATION WILL START AS A RAIN/SNOW
MIX...THEN SWITCH QUICKLY TO SNOW BY LATE AFTERNOON SATURDAY. WITH
THE LACK OF FORCING...DON/T EXPECT TOO MUCH IN TERMS OF LIQUID
AMOUNTS. BUT AS THE COLUMN COOLS BY MORE OF THE SATURATED LAYER WILL
BE IN THE DENDRITIC GROWTH ZONE SO COULD GET SOME HIGH SNOW TO
LIQUID RATIOS TO GIVE UP TO A HALF INCH OF SNOW WITH ONLY A FEW
HUNDREDTHS OF LIQUID. AGAIN...THE LIFT IN THIS LAYER IS VERY MINIMAL
SO NOT EXPECTING MUCH FOR PRECIPITATION SO LEFT CHANCES FOR
MEASURABLE MOISTURE LOW AT THIS POINT.
DOESN`T LOOK TO BE A REAL DEEP LAYER OF MOISTURE AS THE MID LEVELS
LOOK PRETTY DRY. BUT WITH THE COLD AIR ADVECTION BEHIND THE
SYSTEM...THE LAYER THAT IS SATURATED FROM THE SURFACE TO AROUND
700MB...TEMPERATURES DROP THROUGH THE EVENING SO IT LOOKS COLD
ENOUGH FOR SNOW.
SUBSIDENCE TAKES OVER BY LATE SATURDAY NIGHT...WHICH WILL ALLOW THE
CHANCES FOR MEASURABLE PRECIPITATION TO END AFTER MIDNIGHT...THOUGH
WILL KEEP FLURRIES IN THE FORECAST INTO THE MORNING HOURS.
ALSO TO DISCUSS IS WINDS FOR SATURDAY AND SATURDAY NIGHT. A TIGHT
PRESSURE GRADIENT DEVELOPS BEHIND THE FRONT ON SATURDAY AND SATURDAY
NIGHT AND WITH GOOD SUBSIDENCE BEHIND THE SHORTWAVE COULD GET SOME
STRONG WINDS TO MIX DOWN TO THE SURFACE. ALTHOUGH SOME PLACES WON/T
MIX UP TO 850MB...LEVELS IN BETWEEN WILL ALSO SEE PRETTY STRONG
WINDS. AT 850MB...WINDS DO BLOW UP TO 50KTS SO WILL KEEP A CLOSE
LOOK IF THERE MIGHT BE A NEED FOR HEADLINES AT SOME POINT. THESE
WINDS STAY STRONG THROUGH MUCH OF SATURDAY NIGHT...AND WITH THE
STRONG WINDS AND THE COLD TEMPERATURES AND POTENTIALLY SOME LIGHT
SNOW...COULD BE AN INTERESTING NIGHT.
BEYOND SUNDAY...THE RIDGE BUILDS BACK IN OVER THE WEST COAST AND
WITH TROUGHING OVER THE EAST...ONCE AGAIN THE LOCAL AREA GETS STUCK
UNDER BROAD NORTHWEST FLOW. THROUGH THE REMAINDER OF THE PERIOD WILL
SEE A DECENT GRADIENT IN TEMPERATURES FROM NORTHEAST TO SOUTHWEST
ACROSS THE AREA. ALSO...THERE WILL BE A FEW WEAK IMPULSES OF ENERGY
MOVING THROUGH THE NORTHWEST FLOW ACROSS THE LOCAL AREA. THERE MAY
BE A FEW OPPORTUNITIES FOR SOME VERY LIGHT SNOWFALL...PRIMARILY OVER
NORTH CENTRAL NEBRASKA. THE TIMING OF ANY OF THESE SHORTWAVES IS
DIFFERENT BETWEEN MODELS SO NOT A GREAT DEAL OF CONFIDENCE RIGHT
NOW...BUT DO HAVE SOME LIGHT CHANCES IN FOR TUESDAY AND TUESDAY
NIGHT.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z FRIDAY MORNING)
ISSUED AT 535 AM CST THU DEC 26 2013
VFR THROUGH THE PERIOD IN BOTH LOCATIONS.
WEAK ECHOES SHOWING UP ON KLNX 88D CURRENTLY ASSOCIATED WITH VERY
WEAK MID LEVEL FRONTOGENESIS ASSOCIATED WITH UPPER PV ANOMALY
SWINGING THROUGH THE NORTHERN PLAINS. RAP PROXIMITY SOUNDINGS SHOW
A MID LEVEL CLOUD LAYER BUT VERY DRY BELOW SO AT THIS TIME AM NOT
EXPECTING ANY SPRINKLES OR FLURRIES MAKING IT TO THE GROUND. THIS
AREA OF MID LEVEL CLOUDINESS PASSES THROUGH THE AREA BY MID DAY TO
EARLY AFTERNOON WITH MAINLY CLEAR SKIES EXPECTED THEREAFTER. WINDS
MAY BE A BIT GUSTY BY LATE MORNING BUT SHOULD RELAX BY LATE
AFTERNOON OR EARLY EVENING.
&&
.LBF WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...JWS
SYNOPSIS...JWS
SHORT TERM...JWS
LONG TERM...BROOKS
AVIATION...JWS
AREA FORECAST DISCUSSION
NWS HASTINGS NE
557 AM CST THU DEC 26 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 500 AM CST THU DEC 26 2013
WITH A CONTINUED EFFECTIVELY ZERO RISK OF PRECIP DURING THE NEXT
24 HOURS...TEMPS/SKY COVER/WIND SPEEDS REMAIN THE MAIN ISSUES. AS
DESCRIBED IN DETAIL BELOW...BOTH WIND SPEEDS AND ESPECIALLY TEMPS
HAVE BEEN BUMPED UP FOR TODAY...WITH THE MAIN WILD CARD FACTOR
BEING THE EXTENT/DURATION OF INCOMING MID-HIGH LEVEL CLOUDS.
ALTHOUGH MODELS SUCH AS THE NAM AND TO A MUCH LESSER EXTENT THE
RAP CONTINUE TO STRUGGLE WITH POORLY INITIALIZED/OVERDONE SNOW
COVER FIELDS...THE VERY LATEST 06Z NAM HAS FINALLY STARTED
LATCHING ONTO REALITY AND HOPEFULLY HELPS PAVE THE WAY FOR MORE
STRAIGHTFORWARD TEMP FORECASTING OVER THE NEXT FEW DAYS.
STARTING OFF EARLY THIS MORNING AS OF 0930Z THE LATEST 11-3.9
MICRON SATELLITE LOOP REVEALED PREDOMINANTLY CLEAR SKIES OVER THE
CWA...ALTHOUGH A FAIRLY DECENT BATCH OF MID-HIGH CLOUDS WAS
STEADILY APPROACHING THE AREA FROM SD. WATER VAPOR SATELLITE
IMAGERY AND SHORT TERM MODEL DATA DEPICTED CONTINUED NORTHWEST
MID-UPPER LEVEL FLOW OVER THE CENTRAL PLAINS...FLOWING BETWEEN A
LARGE SCALE TROUGH OVER THE EASTERN CONUS AND AN EXPANSIVE RIDGE
CENTERED ALONG/WEST OF THE PACIFIC COAST. ON THE SMALLER SCALE...A
FAIRLY SUBTLE DISTURBANCE WAS MAKING ITS WAY SOUTH-SOUTHEAST
ACROSS THE DAKOTAS AND IS LARGELY RESPONSIBLE FOR THE INCOMING
CLOUDS...WITH THIS FEATURE LOCATED WITHIN THE LEFT EXIT REGION OF
THE LATEST IN A SERIES OF 110+KT UPPER JET STREAKS POKING
SOUTHWARD INTO THE NORTHERN ROCKIES OUT OF SOUTHWESTERN CANADA. AT
THE SURFACE...09Z OBJECTIVE ANALYSIS AND AREA AUTOMATED OBS
REVEALED THE PRESENCE OF A SUBTLE NORTH-SOUTH TROUGH AXIS ACROSS
THE CWA...EXTENDING SOUTHWARD FROM A 1014 MILLIBAR LOW CENTERED
NEAR THE BORDER OF ND/SASKATCHEWAN/MANITOBA. MEANWHILE TO THE
SOUTH...A BROAD 1031MB HIGH WAS CENTERED OVER THE OK/WEST TX AREA.
THE NET RESULT OF THESE FEATURES IS A GENERALLY SOUTHWESTERLY
BREEZE OF 5-10 MPH ACROSS MOST OF THE CWA WITH SOME HIGHER GUSTS.
AS IS TYPICAL...THERE HAS BEEN AN EBB AND FLOW OF TEMPS OVERNIGHT
ACROSS THE CWA...AS THE FACTORS OF CLEAR SKIES AND LOCALIZED VERY
LIGHT BREEZES HAVE ALLOWED SOME PLACES TO FALL FAIRLY
EFFICIENTLY...WHILE OTHER PLACES INCLUDING THE TRI-CITIES HAVE
BEEN HELD UP FAIRLY WELL BY THE WESTERLY BREEZES. ALTHOUGH THESE
FLUCTUATIONS WILL CONTINUE THROUGH DAYBREAK...THE GENERAL
EXPECTATION IS THAT OVERNIGHT LOW TEMPERATURES ACROSS THE MAJORITY
OF THE CWA HAVE SETTLED/WILL SETTLE SOMEWHERE INTO THE 17-24 RANGE.
GETTING INTO THE DAYTIME FORECAST...THE BIG PICTURE ALOFT IN THE
MID-UPPER LEVELS INVOLVES THE CONTINUATION OF VERY SUBTLE HEIGHT
RISES AS EVIDENT AT 500MB...AS THE DISTURBANCE CURRENTLY CENTERED
OVER THE DAKOTAS TRACKS SOUTHEAST OVER MAINLY EASTERN PORTIONS OF
THE LOCAL AREA...BUT ESPECIALLY INTO THE IA/MN AREA...ALLOWING THE
WESTERN RIDGE TO NUDGE EVER SO SLIGHTLY EAST INTO THE CENTRAL PLAINS.
AS THIS OCCURS...THE TRAILING NORTH-SOUTH ORIENTED UPPER JET
STREAK WILL ALSO SLIDE EAST FROM THE NORTHERN ROCKIES INTO THE
DAKOTAS OVER THE COURSE OF THE DAY. AT THE SURFACE TODAY...THERE
WILL BE A SIMILAR SCENARIO TO WHAT OCCURRED YESTERDAY...AS
INITIALLY SOUTHWESTERLY BREEZES WILL SWITCH TO NORTHWESTERLY IN
RESPONSE TO THE EASTWARD PROGRESSION OF THE PARENT SURFACE TROUGH
CENTERED TO THE NORTH. AS MIXING HEIGHTS INCREASE TO THE 900-875MB
RANGE PER RAP SOUNDINGS...WIND SPEEDS WILL PICK UP WITH SUSTAINED
NORTHWESTERLY SPEEDS OF 15-20 MPH AND GUSTS UP TO AROUND 25
MPH...WITH THE MAIN TIME FRAME OF STRONGEST BREEZES CENTERED
BETWEEN LATE MORNING AND MID-AFTERNOON BEFORE SUBSIDING AGAIN
LATER IN THE AFTERNOON. THESE WIND SPEEDS REFLECT ROUGHLY A 5 MPH
INCREASE VERSUS PREVIOUS FORECAST FOR MUCH OF THE AREA. TURNING TO
SKY COVER...THIS IS A BIT OF A QUESTION MARK TODAY AS MODELS ARE
HANDLING THE INCOMING CLOUD DECK SOMEWHAT DIFFERENTLY. THE GENERAL
EXPECTATION THOUGH IS THAT ALTHOUGH ESPECIALLY NORTHERN PARTS OF
THE AREA COULD GO MOSTLY CLOUDY FOR A TIME THIS MORNING...THE
OVERALL DENSITY OF THIS CLOUD DECK SHOULD FADE WITH TIME AND WITH
SOUTHWARD EXTENT...RESULTING IN NO WORSE THAN PARTLY CLOUDY IF NOT
MOSTLY SUNNY CONDITIONS THROUGH THE BALANCE OF THE DAY. PUT
ANOTHER WAY...THE CURRENT SKY COVER GRIDS MAY NOT BE QUITE
AGGRESSIVE ENOUGH FOR LATER THIS MORNING...BUT THINK THAT THE DAY
OVERALL WILL FEATURE MORE SUN THAN CLOUDS. AS FOR TEMPS TODAY...FOR
NOW WILL ASSUME A RATHER NEGLIGIBLE EFFECT OF PASSING CLOUD
COVER...AND THUS GIVEN THE DECENT LOW LEVEL MIXING REGIME IN
PLACE...HAVE BOOSTED HIGH TEMPS AT LEAST A FEW DEGREES VERSUS
PREVIOUS FORECAST ACROSS THE NORTHERN HALF OF THE CWA...AND AS
MUCH AS 5-9 DEGREES IN THE SOUTH. BASED ON WHAT HAPPENED
YESTERDAY...NEARLY ALL PRIMARY MODELS/GUIDANCE FELL AT LEAST
SLIGHTLY SHORT OF ACTUAL HIGHS...BUT HOURLY RAP13 TEMPS ENDED UP
BEING ONE OF THE BEST SOLUTIONS. AS A RESULT...HAVE AGAIN OPTED TO
FOLLOW RAP13 TEMPS QUITE CLOSELY TODAY...WHICH RESULTS IN HIGHS
GENERALLY 4-7 DEGREE WARMER THAN A SIMPLE BLEND OF 00Z MET/MAV
GUIDANCE. THE NET RESULT IS HIGH TEMPERATURES AIMED FROM THE UPPER
40S/LOW 50S IN THE NORTHERN 1/2 OF THE CWA TO PREDOMINANTLY MID-
50S IN KS ZONES. IF ANYTHING...MIGHT NOT HAVE GONE WARM ENOUGH IN
NORTHEAST ZONES. THIS INCREASE IN HIGH TEMPS RESULTS IN AFTERNOON
RELATIVE HUMIDITY VALUES FORECAST TO DROP AROUND 25 PERCENT OR
SLIGHTLY LOWER IN SOUTHWESTERN COUNTIES...BUT GIVEN THAT SUSTAINED
WINDS SHOULD AVERAGE CLOSER TO 15 MPH THAN 20 MPH IN THESE
AREAS...THE SETUP APPEARS TO FALL A BIT SHORT OF JUSTIFYING A
NEAR-CRITICAL FIRE DANGER MENTION IN THE HAZARDOUS WEATHER
OUTLOOK.
TURNING TO THIS EVENING/TONIGHT...THE LARGE SCALE SYNOPTIC PICTURE
INVOLVES THE CONTINUED EXPANSION OF THE WESTERN CONUS RIDGE
EASTWARD OVER THE CENTRAL PLAINS...ACCOMPANIED BY RESULTANT MID-
LEVEL HEIGHT RISES. ALTHOUGH THE PRIMARY UPPER JET CORE WILL
CONTINUE TO SLIDE OFF TO THE NORTH-NORTHEAST OF THE AREA...THE
CONTINUED NORTH-NORTHWESTERLY FLOW ALOFT OVER THE CENTRAL PLAINS
WILL NONETHELESS FEATURE THE PASSAGE OF AT LEAST ONE SUBTLE...LOW-
AMPLITUDE SHORTWAVE TROUGH DURING THE NIGHT. ALTHOUGH THIS COULD
EASILY RESULT IN A MODEST INCREASE IN MID-HIGH LEVEL CLOUDS MAINLY
AFTER MIDNIGHT AND MAINLY IN NORTHERN ZONES...THE NIGHT AS A WHOLE
SHOULD AVERAGE NO WORSE THAN MOSTLY CLEAR ACROSS THE ENTIRE CWA.
AT THE SURFACE TONIGHT...A NOW-FAMILIAR PATTERN WILL AGAIN REPEAT
ITSELF...AS A SUBTLE TROUGH AXIS WILL AGAIN EXTEND SOUTHWARD INTO
THE CENTRAL PLAINS FROM A PARENT LOW PRESSURE SYSTEM CENTERED WELL
TO THE NORTH OVER SOUTH CENTRAL CANADA. THIS WILL AGAIN TRANSITION
THE NORTHWESTERLY BREEZES OF THIS AFTERNOON TO FAIRLY LIGHT
WESTERLY BREEZES THIS EVENING...AND THEN 5-10 MPH SOUTHWESTERLY
BREEZES AFTER MIDNIGHT. WITH THE SKY COVER...WIND SPEED/DIRECTION
AND LOW LEVEL THERMAL PROFILES TONIGHT SETTING UP TO BE QUITE
SIMILAR TO THOSE OF THIS MORNING...SEE NO REASON WHY TEMPERATURE
BEHAVIOR WON/T BE SIMILAR AS WELL...WITH PLENTY OF HOUR-TO-HOUR
AND SMALL-SCALE VARIABILITY. ALTHOUGH VERY LITTLE CHANGE WAS MADE
TO LOWS FROM THE PREVIOUS FORECAST...STILL CALLING FOR NEARLY THE
ENTIRE CWA TO SETTLE WITHIN A FEW DEGREES EITHER SIDE OF 20 AT
SOME POINT IN THE NIGHT...THIS IS STILL A FEW DEGREES ABOVE A
STRAIGHT-UP 00Z MET/MAV GUIDANCE BLEND...AND WOULD NOT BE
SURPRISED IF THE NEXT SHIFT CONSIDERS RAISING LOWS A BIT MORE IN
SOME PLACES.
.LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 500 AM CST THU DEC 26 2013
THE BIGGEST CHALLENGE WILL BE DETERMINING THE TIMING OF A COLD FRONT
SATURDAY...WHICH WILL SUBSEQUENTLY AFFECT HIGH TEMPERATURES ON
SATURDAY AND WIND SPEEDS SATURDAY/SATURDAY NIGHT.
WE BEGIN THE LONG TERM FORECAST IN A TRANSITION OF SORTS. THE RIDGE
OVER THE WESTERN UNITED STATES WILL DEAMPLIFY AS IT MOVES
EAST...BEING BROKEN DOWN BY AN APPROACHING SHORTWAVE TROUGH ENTERING
THE COAST OF THE PACIFIC NORTHWEST BY LATE DAY FRIDAY. WE WILL
CLEARLY BE IN THE WARM SECTOR WITH HIGHS EASILY REACHING THE 50S FOR
MOST LOCATIONS IF NOT 60 FOR MUCH OF NORTH CENTRAL KANSAS. MODEL
OUTPUT IS NOT OPTIMAL FOR MAXIMUM TEMPERATURE FORECASTS AS A PHANTOM
SNOWPACK LINGERS OVER MUCH OF THE AREA AND IS DISTURBING THE MODEL
SOLUTIONS...ESPECIALLY FOR MAX T AND WIND FIELDS. REALLY HAD TO LEAN
ON ENSEMBLE DATA AND OPERATIONAL MODELS SUCH AS THE ECMWF THAT
EITHER DO NOT INCLUDE SNOWPACK...OR HAVE LIMITED SNOWPACK DATA
ENTERED INTO MODEL INITIALIZATIONS. THE NAM...SPECIFICALLY...IS
ATROCIOUS AND HAS AFFECTED OTHER SOLUTIONS SUCH AS
CONSRAW...BCCONSRAW...CONSALL...ETC. THIS HAS RENDERED MUCH OF THESE
DATA RATHER USELESS FOR MAXIMUM TEMPERATURE AND WIND FIELDS.
I WENT CLOSER TO CONSRAW OUTPUT FOR MINIMUM TEMPERATURES FRIDAY
NIGHT AS THIS OUTPUT SEEMED TO BE LARGELY UNAFFECTED BY THE
ERRONEOUS SNOWPACK AND THIS OUTPUT TENDS TO DO BEST FOR LOW
TEMPERATURES FOR THE LAST NIGHT BEFORE A COLD FRONT PASSAGE. THE
SREF ADVERTISES QUITE A BIT OF FOG FOR FRIDAY NIGHT...ESPECIALLY IN
OUR EAST...BUT WITH A SOUTHWEST WIND THAT WILL NOT BE PARTICULARLY
LIGHT...I AM DISCOUNTING THIS ADVERTISEMENT.
SATURDAY WILL BE TRICKY AS THE AFOREMENTIONED TROUGH TO THE NORTHWEST
SWEEPS RATHER QUICKLY INTO THE PLAINS...JOINING WITH ANOTHER TROUGH
SWINGING DOWN FROM CANADA TO REINFORCE A SIGNIFICANT SHOT OF MUCH
COLDER AIR. THE TRICKY PART WILL BE TIMING THE ASSOCIATED COLD
FRONT. MODEL SOLUTIONS GENERALLY CONCUR THAT MOST OF THE CWA SHOULD
BE ABLE TO GET IN ONE MORE DAY OF GOOD WARM AIR ADVECTION AHEAD OF
THE COLD FRONT BEFORE IT COMES IN. THE FAR WESTERN AND NORTHERN CWA
ARE MOST AT RISK OF NOT REALIZING TEMPERATURES AS WARM OR WARMER
THAN WHAT OCCURRED ON FRIDAY. I INCREASED TEMPERATURES FOR MOST OF
THE CWA FROM THE PREVIOUS FORECAST...BUT KEPT TEMPERATURES IN THE FAR
WESTERN/NORTHWESTER CWA RATHER SIMILAR AS MEDIUM RANGE MODELS
INDICATE THAT THE COLD FRONT SHOULD MAKE ITS WAY JUST INTO THE CWA
BY NOON SATURDAY. HOWEVER...THE FORECAST FOR MID 50S FOR SATURDAY
COULD CRASH AND BURN RATHER EASILY IF THE COLD AIR COMES IN
FASTER...SO THE CONFIDENCE FOR HIGH TEMPERATURES...ESPECIALLY FROM
THE TRI-CITIES AND FARTHER NORTHWEST...IS NOT AS HIGH AS IT COULD
BE...ESPECIALLY WITH THE POOR MODEL OUTPUT AS OF LATE. HEIGHT RISES
ARE IMPRESSIVE ALONG WITH COLD AIR ADVECTION BEHIND THE COLD
FRONT...ALTHOUGH THESE VARIABLES REALLY TAKE HOLD LATER INTO SATURDAY
NIGHT. I RAISED WIND SPEEDS SIGNIFICANTLY FROM THE PREVIOUS FORECAST
BECAUSE OF THIS...AND WE SHOULD BE IN THE REALM OF WIND ADVISORY AS
FAR SOUTH AS THE TRI-CITIES...AND NOT TOO FAR FROM WIND ADVISORY
FARTHER SOUTH IN OUR CWA FOR SATURDAY NIGHT. THIS CONTINUES TO LOOK
LIKE A DRY FORECAST WITH THE PASSING OF THE COLD FRONT AS THE
MOISTURE PROFILE IS QUITE DRY...ALTHOUGH THERE COULD CERTAINLY BE
SOME STRATUS FOR AWHILE DUE TO THE STRONG COLD AIR ADVECTION AND A
FLURRY IS NOT COMPLETELY OUT OF THE QUESTION. ALTHOUGH MID-LEVELS
ARE QUITE DRY...ANY SATURATION WILL OCCUR AT TEMPERATURES FAR TOO
COLD TO SUPPORT FREEZING DRIZZLE. THE COMBINATION OF THE STRATUS AND
WIND SHOULD KEEP TEMPERATURES FROM BOTTOMING OUT TOO MUCH AND THE
TEMPERATURES FROM THE PREVIOUS FORECAST LOOK PERFECTLY REASONABLE.
JUDGING BY WHAT HAPPENED WITH THE LAST COLD SNAP...I SUSPECT THAT
MODELS ARE GOING TO WANT TO SCOOT THE COLD AIR TO THE EAST TOO
QUICKLY AS THE DEVELOPING UPPER LEVEL RIDGE TO THE WEST TRIES TO
BUILD EAST. THIS IS CONFIRMED BY ENSEMBLE TRENDS FROM THE ECMWF AND
THE GFS. I WENT COLDER THAN THE INITIALIZED ALLBLEND AND PREVIOUS
FORECASTS...ESPECIALLY FOR HIGHS SUNDAY AND MONDAY...AND ALSO LOWS
FOR SUNDAY NIGHT/MONDAY MORNING. THE CENTER OF THE SURFACE HIGH
SHOULD MAKE ITS WAY ACROSS THE CWA SUNDAY NIGHT/MONDAY MORNING TO
ALLOW WINDS TO DROP SIGNIFICANTLY. UNDER CLEAR/MOSTLY CLEAR SKIES
AND WIND BECOMING VERY LIGHT OR CALM NEAR THE CENTER OF THE SURFACE
HIGH...THIS SHOULD ALLOW TEMPERATURES TO REALLY TANK INTO THE SINGLE
DIGITS...AND THEY COULD TANK RELATIVELY EARLY IN THE
NIGHT...DEPENDING ON THE TIMING OF THE SURFACE HIGH.
ONE MORE THING OF NOTE...I STUCK IN A SLIGHT CHANCE OF SNOW IN THE
NORTHEASTERN CWA FOR WEDNESDAY FROM AN IMPULSE WITHIN NORTHWEST
FLOW. TIMING AND POSITIONING ARE DICEY...SO CHANCES OF PRECIPITATION
ARE NOT HIGH IN THE FORECAST. SINCE MORE THAN ONE MODEL SOLUTION
ADVERTISES A SHORTWAVE TROUGH MOVING IN AT ROUGHLY THIS TIME...IT IS
PRUDENT TO INTRODUCE THIS TO THE LONG TERM FORECAST.
&&
.AVIATION...(FOR THE 12Z KGRI TAF THROUGH 12Z FRIDAY MORNING)
ISSUED AT 557 AM CST THU DEC 26 2013
CONFIDENCE REMAINS HIGH IN VFR CEILING/VISIBILITY THROUGH THE NEXT
24 HOURS...WITH ONLY LIMITED COVERAGE OF PASSING MID-HIGH LEVEL
CLOUDS. THAT LEAVES SURFACE WINDS AS THE MAIN ISSUE. BOTH EARLY
THIS MORNING AND AGAIN THIS EVENING/TONIGHT...WINDS WILL AVERAGE
FROM SOME VARIATION OF WESTERLY AT SUSTAINED SPEEDS GENERALLY
NEAR/UNDER 10KT. HOWEVER...FOR SEVERAL HOURS DURING THE HEART OF
THE DAY...ESPECIALLY BETWEEN 17-21Z...THERE WILL LIKELY BE A
PERIOD OF ENHANCED NORTHWEST BREEZES BEHIND A PASSING SURFACE
TROUGH AS VERTICAL MIXING INCREASES. DURING THIS TIME...WIND GUST
POTENTIAL WILL INCREASE TO AROUND 20KT BEFORE SUBSIDING BY LATE
AFTERNOON. ALTHOUGH THERE WILL BE A DIRECTIONAL CHANGE FROM
NORTHWESTERLY TO SOUTHWESTERLY OVERNIGHT...FORECAST SPEEDS ARE NOT
HIGH ENOUGH TO JUSTIFY AN ADDITIONAL FROM-GROUP AFTER 00Z.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
KS...NONE.
&&
$$
SHORT TERM...PFANNKUCH
LONG TERM...HEINLEIN
AVIATION...PFANNKUCH
AREA FORECAST DISCUSSION
NWS NORTH PLATTE NE
535 AM CST THU DEC 26 2013
.SYNOPSIS...
ISSUED AT 343 AM CST THU DEC 26 2013
NEXT IN THE SERIES OF UPPER PV ANOMALIES...CURRENTLY LOCATED OVER
ERN MT...WILL DROP ACROSS THE NORTHERN PLAINS TODAY...ORIGINATING
FROM THE NORTHERN PACIFIC REGION INSTEAD OF THE ARCTIC. AHEAD OF THE
FEATURES WESTERLY OR SOUTHWESTERLY COMPONENT TO THE WINDS JUST OFF
THE SURFACE IS BRINGING WARMER AIR TO THE WESTERN HIGH PLAINS AND
CONTINUING INTO THE MORNING HOURS. AT THE HEMISPHERIC SCALE...A
PROGRESSIVE PATTERN REMAINS ACROSS THE NORTHERN HEMISPHERE WITH AN
UPPER LOW MOVING QUICKLY INTO THE ERN U.S. AND HIGH PRESSURE ALOFT
BUILDING INTO THE PAC NW.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 343 AM CST THU DEC 26 2013
PREVIOUSLY MENTIONED PV ANOMALY DIVES SOUTHEAST ACROSS THE NORTHERN
PLAINS WHICH WILL DRIVE A WEAK COLD FRONT ACROSS THE AREA LATER IN
THE DAY. BRIEF WARM AIR ADVECTION THIS MORNING WILL ALLOW TEMPS TO
BE WARMER THAN YESTERDAY AND ALTHOUGH WINDS WILL BECOME NWRLY BY
AFTERNOON...COOLER AIR LAGS THE WEAK FRONT SOMEWHAT AND IS WEAK
ESPECIALLY IN THE WEST. IN ADDITION...JET DYNAMICS ARE NOT FAVORABLE
FOR LARGE SCALE ASCENT AND DRIER AIR IN THE MID LEVELS ACCOMPANYING
THE WARMER AIR AHEAD OF THE SYSTEM WOULD PRECLUDE ANY PRECIP
DEVELOPMENT ANYWAY. RESULT IS SOME MID AND HIGH CLOUDS BY LATE
MORNING INTO THE AFTERNOON...COVERAGE SHOULD NOT LIMIT MAX TEMPS
FROM REACHING LEVELS 10 TO 12 DEGREES ABOVE AVERAGE IN THE
SOUTH...BUT ONLY A FEW DEGREES ABOVE AVE IN THE NORTH. STILL SOME
SNOW COVER ACROSS SHERIDAN AND WESTERN CHERRY COUNTIES SO SOME
INFLUENCE ON TEMPS THERE...BUT OTHERWISE MAINLY OPEN GROUND. NAM
TEMPS ARE HEAVILY INFLUENCED STILL BY HAVING TOO MUCH SNOW COVER
ANALYZED.
UPPER RIDGE BUILD ACROSS THE WEST OVER NIGHT WITH GOOD SUBSIDENCE
CLEARING CLOUDS. WILL ALLOW FOR GOOD RADIATIONAL COOLING BUT LOW
TEMPS STILL ABOVE AVE FOR THIS TIME OF YEAR.
.LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 343 AM CST THU DEC 26 2013
FORECAST FOCUS FOR FRIDAY INTO SATURDAY IS TEMPERATURES. THE THERMAL
RIDGE ALOFT KEEPS TEMPERATURES ABNORMALLY WARM...WITH 850MB
TEMPERATURES AT 9C TO 11C FRIDAY AND FRIDAY NIGHT. MODELS
/ESPECIALLY THE NAM/ ARE HAVING SOME ISSUES WITH THE SNOW
COVER...AND THUS THE AMOUNT OF MIXING/WARMING THAT WILL BE REALIZED
ON FRIDAY. THERE MAY BE SOME HIGH CLOUDS BUT NOT EXPECTING ENOUGH TO
MAKE A HUGE IMPACT ON HIGHS. WILL ALSO HAVE BREEZY WESTERLY WINDS TO
ENHANCE THE DOWNSLOPE WARMING EFFECT...AND HELP WARM TEMPERATURES TO
THE UPPER 40S AND 50S. LOWS FRIDAY NIGHT SHOULD STAY FAIRLY MILD AS
THE WINDS STAY UP AND CLOUDS INCREASE DUE TO AN INCOMING FRONTAL
BOUNDARY.
AN UPPER LEVEL TROUGH WILL PASS ACROSS THE PLAINS SATURDAY NIGHT
INTO SUNDAY. MODEL SOLUTIONS ARE IN GOOD AGREEMENT THAT IMPACT
LOCALLY WILL BE MINIMAL...WITH THE PRIMARY CONCERNS BEING A CHANGE
IN TEMPERATURES.
THERE ARE TWO PRIMARY PV ANOMALIES THAT WILL MOVE THROUGH THE
TROUGH...THE FIRST ORIGINATES OVER THE YUKON AND NORTHWEST
TERRITORIES WHICH THEN DIGS SOUTHWARD AND MOVES THROUGH THE DAKOTAS
ON SUNDAY. THE SECOND IS THE SYSTEM CURRENTLY OUT OVER THE NORTHERN
PACIFIC WHICH WILL MOVE EAST AND DAMPEN THE RIDGE AND MOVE INTO THE
PACIFIC NORTHWEST FRIDAY THEN PROGRESS THROUGH THE TROUGH WITH THE
MAIN PART OF THE PV ANOMALY STAYING WELL SOUTH OF THE FORECAST
AREA...THROUGH THE FOUR CORNERS AND INTO THE SOUTHERN PLAINS. THESE
TWO BITS OF ENERGY WILL NOT PHASE TOGETHER SO UPWARD FORCING WILL
NOT BE GREAT IN THE LOCAL AREA AS THESE SYSTEMS PASS. DID KEEP LOW
CHANCES ACROSS NORTHERN NEBRASKA INTO THE PANHANDLE ON SATURDAY
AFTERNOON AND SATURDAY NIGHT AS SOUNDINGS AND CROSS SECTIONS DO SHOW
A BIT OF LIFT IN THE SATURATED LAYER...WHICH IS FAIRLY LOW...BELOW
700MB. AS THE MOISTURE WON/T BE DEEP...A CONCERN IS PRECIPITATION
TYPE WITH THE STRONG COLD AIR ADVECTION DURING THE DAY SATURDAY.
AHEAD OF THE FRONT AT 12Z SATURDAY...MODEL SOLUTIONS ARE SHOWING
850MB TEMPERATURES OF 10C TO 12C AND BY 00Z SUNDAY RANGE FROM -13C
IN THE NORTHERN PANHANDLE TO AROUND 0C OVER SOUTH CENTRAL NEBRASKA.
BELIEVE WITH THIS DRASTIC MOVEMENT OF COLD AIR...WILL LIKELY SEE A
NON-DIURNAL CURVE FOR TEMPERATURES ON SATURDAY. AREAS ACROSS THE
NORTH WILL PROBABLY ONLY RISE INTO THE MID TO UPPER 30S AND LOW
40S...WHILE ACROSS THE SOUTHERN PART WILL BE MUCH WARMER. CURRENTLY
HAVE UPPER 40S AND LOW 50S IN THE FORECAST THINKING THERE WILL BE
GOOD MIXING RIGHT ALONG AND AHEAD OF THE FRONT TO BRING WARMER
TEMPERATURES TO THESE AREAS. THE COLD AIR LOOKS TO MOVE IN FAIRLY
UNIFORMLY ACCORDING TO FORECAST SOUNDINGS SO A GOOD WARM LAYER DOES
NOT SET UP...WHICH MEANS PRECIPITATION WILL START AS A RAIN/SNOW
MIX...THEN SWITCH QUICKLY TO SNOW BY LATE AFTERNOON SATURDAY. WITH
THE LACK OF FORCING...DON/T EXPECT TOO MUCH IN TERMS OF LIQUID
AMOUNTS. BUT AS THE COLUMN COOLS BY MORE OF THE SATURATED LAYER WILL
BE IN THE DENDRITIC GROWTH ZONE SO COULD GET SOME HIGH SNOW TO
LIQUID RATIOS TO GIVE UP TO A HALF INCH OF SNOW WITH ONLY A FEW
HUNDREDTHS OF LIQUID. AGAIN...THE LIFT IN THIS LAYER IS VERY MINIMAL
SO NOT EXPECTING MUCH FOR PRECIPITATION SO LEFT CHANCES FOR
MEASURABLE MOISTURE LOW AT THIS POINT.
DOESN`T LOOK TO BE A REAL DEEP LAYER OF MOISTURE AS THE MID LEVELS
LOOK PRETTY DRY. BUT WITH THE COLD AIR ADVECTION BEHIND THE
SYSTEM...THE LAYER THAT IS SATURATED FROM THE SURFACE TO AROUND
700MB...TEMPERATURES DROP THROUGH THE EVENING SO IT LOOKS COLD
ENOUGH FOR SNOW.
SUBSIDENCE TAKES OVER BY LATE SATURDAY NIGHT...WHICH WILL ALLOW THE
CHANCES FOR MEASURABLE PRECIPITATION TO END AFTER MIDNIGHT...THOUGH
WILL KEEP FLURRIES IN THE FORECAST INTO THE MORNING HOURS.
ALSO TO DISCUSS IS WINDS FOR SATURDAY AND SATURDAY NIGHT. A TIGHT
PRESSURE GRADIENT DEVELOPS BEHIND THE FRONT ON SATURDAY AND SATURDAY
NIGHT AND WITH GOOD SUBSIDENCE BEHIND THE SHORTWAVE COULD GET SOME
STRONG WINDS TO MIX DOWN TO THE SURFACE. ALTHOUGH SOME PLACES WON/T
MIX UP TO 850MB...LEVELS IN BETWEEN WILL ALSO SEE PRETTY STRONG
WINDS. AT 850MB...WINDS DO BLOW UP TO 50KTS SO WILL KEEP A CLOSE
LOOK IF THERE MIGHT BE A NEED FOR HEADLINES AT SOME POINT. THESE
WINDS STAY STRONG THROUGH MUCH OF SATURDAY NIGHT...AND WITH THE
STRONG WINDS AND THE COLD TEMPERATURES AND POTENTIALLY SOME LIGHT
SNOW...COULD BE AN INTERESTING NIGHT.
BEYOND SUNDAY...THE RIDGE BUILDS BACK IN OVER THE WEST COAST AND
WITH TROUGHING OVER THE EAST...ONCE AGAIN THE LOCAL AREA GETS STUCK
UNDER BROAD NORTHWEST FLOW. THROUGH THE REMAINDER OF THE PERIOD WILL
SEE A DECENT GRADIENT IN TEMPERATURES FROM NORTHEAST TO SOUTHWEST
ACROSS THE AREA. ALSO...THERE WILL BE A FEW WEAK IMPULSES OF ENERGY
MOVING THROUGH THE NORTHWEST FLOW ACROSS THE LOCAL AREA. THERE MAY
BE A FEW OPPORTUNITIES FOR SOME VERY LIGHT SNOWFALL...PRIMARILY OVER
NORTH CENTRAL NEBRASKA. THE TIMING OF ANY OF THESE SHORTWAVES IS
DIFFERENT BETWEEN MODELS SO NOT A GREAT DEAL OF CONFIDENCE RIGHT
NOW...BUT DO HAVE SOME LIGHT CHANCES IN FOR TUESDAY AND TUESDAY
NIGHT.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z FRIDAY MORNING)
ISSUED AT 535 AM CST THU DEC 26 2013
VFR THROUGH THE PERIOD IN BOTH LOCATIONS.
WEAK ECHOES SHOWING UP ON KLNX 88D CURRENTLY ASSOCIATED WITH VERY
WEAK MID LEVEL FRONTOGENESIS ASSOCIATED WITH UPPER PV ANOMALY
SWINGING THROUGH THE NORTHERN PLAINS. RAP PROXIMITY SOUNDINGS SHOW
A MID LEVEL CLOUD LAYER BUT VERY DRY BELOW SO AT THIS TIME AM NOT
EXPECTING ANY SPRINKLES OR FLURRIES MAKING IT TO THE GROUND. THIS
AREA OF MID LEVEL CLOUDINESS PASSES THROUGH THE AREA BY MID DAY TO
EARLY AFTERNOON WITH MAINLY CLEAR SKIES EXPECTED THEREAFTER. WINDS
MAY BE A BIT GUSTY BY LATE MORNING BUT SHOULD RELAX BY LATE
AFTERNOON OR EARLY EVENING.
&&
.LBF WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...JWS
SHORT TERM...JWS
LONG TERM...BROOKS
AVIATION...JWS
AREA FORECAST DISCUSSION
NWS CHARLESTON WV
725 AM EST THU DEC 26 2013
.SYNOPSIS...
WEAK COLD FRONT PUSHES EAST THIS MORNING. THEN HIGH PRESSURE
THROUGH SATURDAY. LOW PRESSURE MOVES UP THE EAST COAST
SUNDAY...WITH A COLD FRONT FOR SUNDAY NIGHT.
&&
.NEAR TERM /THROUGH TONIGHT/...
SENT A QUICK UPDATE ON WINDS AS SFC OBS AND RUC13 ISENTROPIC SFC
AT 275K SUGGEST 25 TO 30 KNOTS CLOSE TO THE GROUND INCREASING AND
VEERING FROM SOUTH TO WEST BY 15Z. REST OF FORECAST REMAINS
REPRESENTATIVE.
&&
.SHORT TERM /FRIDAY THROUGH SUNDAY/...
HIGH PRESSURE IN CONTROL TO START THE SHORT TERM PERIOD WITH A GOOD
AMOUNT OF SUNSHINE DURING THE DAY BUT ALSO DECENT RADIATIONAL
COOLING AT NIGHT. INCREASED POPS PRETTY SIGNIFICANTLY SATURDAY NIGHT
INTO SUNDAY AS LOW PRESSURE SLIDES ACROSS THE SOUTHEAST US. GFS AND
ECMWF IN DECENT AGREEMENT ON THIS SYSTEM...WHILE NAM HAS A MUCH
TIGHTER GRADIENT ON THE MOISTURE KEEPING MOST OF THE CWA DRY.
TRENDED TOWARDS A GFS/ECMWF BLEND...WHICH AGREES WITH WPC GUIDANCE
AS WELL. WHILE CONFIDENCE IS RATHER LOW IN P-TYPE FORECAST...HAVE
TEMPERATURE PROFILE WARM ENOUGH FOR MOSTLY RAIN...BUT WITH SOME
WINTRY MIX EARLY SUNDAY MORNING.
USED A BLEND OF MAV/MET MOS FOR HIGHS AND LOWS THROUGH
SATURDAY...THEN TRANSITIONED TO BLENDING IN CONSENSUS GUIDANCE.
&&
.LONG TERM /SUNDAY NIGHT THROUGH WEDNESDAY/...
MAIN STORY THIS PERIOD IS A SOUTHERN STREAM SYSTEM NOW PROGGED TO
IMPACT THE AREA WITH PRECIPITATION...MAINLY IN SUNDAY.
CONFLUENCE ZONE BETWEEN NORTHERN AND SOUTHERN STREAMS IS NOW SHOWN
TO GET N OF THE FCST AREA...EVEN N OF THE MASON-DIXON LINE...SAT
NT. THIS ALLOWS MOISTURE TO WORK NWWD INTO THE FCST AREA SAT NT.
SFC LOW IS PROGGED TO TRACK NEWD TO COASTAL S CAROLINA SUN MORNING
AND THEN OFF THE MIDDLE ATLANTIC SEABOARD SUN AFTERNOON BEFORE
RACING OUT OVER THE OPEN ATLANTIC SUN NT.
WITH NO COLD AIR ASSOCIATED WITH THIS SYSTEM...OR FCST TO INTERACT
WITH THIS SYSTEM AT ANY POINT...PRECIPITATION TYPE SHOULD BE MAINLY
RAIN. POCKETS OF FREEZING RAIN BRIEFLY IN THE DEEPER HOLLOWS IS NOT
OUT OF THE QUESTION AS IT RADIATES SAT EVENING. HAVE BRIEF SNOW IN
THE NORTHERN MOUNTAINS AT THE START EARLY SUNDAY MORNING FOR NOW.
NORTHERN STREAM DRIVEN COLD FRONT CROSSES SUN NT...ITS MAIN IMPACT
BEING UPSLOPE SNOW SHOWERS IN ITS WAKE INTO MON NT.
A BROAD L/W TROUGH AMPLIFIES OVER CENTRAL AND EASTERN NORTH AMERICA
EARLY NEXT WEEK...AS A RIDGE AMPLIFIES UPON MOVING ONSHORE ON THE W
COAST. THIS BRINGS ABOUT A CHILLY...MAINLY DRY INTERLUDE FOR
MIDWEEK. ANOTHER COLD FRONT IS DRIVEN SWD THROUGH THE AREA DURING
THAT TIME...BUT WITH LIMITED MOISTURE WITH IT AND EVEN LIMITED
UPSLOPE IN ITS WAKE...HAVE DRY FCST AT THIS TIME.
FURTHER AMPLIFICATION OF THE L/W TROUGH ADVERTISED VIA THE OVERNIGHT
GFS AND ECMWF RUNS LEADING TO A MAJOR ARCTIC OUTBREAK IN THE E LATE
NEXT WEEK...HAS DISAPPEARED FROM BOTH MODELS FOR THE 12Z CYCLE.
YET...IT IS NOT OUT OF THE QUESTION AMPLIFICATION TO A SIMILAR
DEGREE PANS OUT SOMETIME DURING THE FIRST WEEK OR TWO OF THE NEW
YEAR...2014.
USED BIAS CORRECTED BLEND OF GUIDANCE TO RAISE HIGHS A BIT
SUN...EXCEPT A BIT LOWER UNDER CLOUDS AND RAIN IN THE E. NO CHANGES
TO HIGHS MON WITH VALUES ALREADY NEAR THE CENTER OF THE GUIDANCE
ENVELOPES. RAISED HIGHS TUE A BIT VIA HPC AND GFS-BASED GUIDANCE.
NO CHANGES TO HIGHS NEXT WED...STILL NEAR LOW END OF GUIDANCE. USED
CONSENSUS GUIDANCE FOR LOWS...BIAS CORRECTED EARLY ON AND STRAIGHT
UP DAY 6 AND 7 NTS. LOWS HIGHER THEN PREVIOUS SAT NT WITH SOUTHERN
STREAM SYSTEM COMING IN...AND OCCUR EARLY...ALSO HIGHER TUE NT WITH
LITTLE CHANGE OVER THE MIDDLE OF THE PERIOD WITH HPC ALSO BLENDED IN.
&&
.AVIATION /13Z THURSDAY THROUGH MONDAY/...
A BAND OF FLURRIES/SHSN WITH IFR CONDITIONS WILL PUSH EAST OF THE
REGION BY 15Z. HOWEVER...AN UPPER LEVEL TROUGH WILL CONTINUE THE
CHANCES FOR MVFR CONDITIONS IN FLURRIES/SHSN ACROSS SOUTHEAST OHIO
AND NORTHERN WEST VIRGINIA THROUGH 18Z. ACROSS THE REMAINDER OF
THE REGION...VFR CONDITIONS SHOULD PREVAIL.
THE TROUGH WILL THEN PUSH EAST WITH VFR CONDITIONS EXPECTED
REGION-WIDE BY 21Z.
FLOW TURNS MORE W THIS MORNING AND INCREASES WITH SOME 15 TO 25
KT GUSTS MOST SITES DURING MIXING HOURS...HIGHEST ACROSS N SITES.
THE FLOW SHOULD THEN BECOME LIGHT SOUTHERLY AFTER 00Z.
FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 12Z FRIDAY...
FORECAST CONFIDENCE: HIGH.
ALTERNATE SCENARIOS: IF SNOW SHOWER COVERAGE IS GREATER THAN
EXPECTED...CHANCES FOR OCCASIONAL IFR CONDITIONS AT NORTHERN TAF
SITES WILL BE INCREASED THROUGH 18Z.
EXPERIMENTAL TABLE OF FLIGHT CATEGORY OBJECTIVELY SHOWS CONSISTENCY
OF WFO FORECAST TO AVAILABLE MODEL INFORMATION:
H = HIGH: TAF CONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL.
M = MEDIUM: TAF HAS VARYING LEVEL OF CONSISTENCY WITH MODELS.
L = LOW: TAF INCONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL.
UTC 1HRLY 11 12 13 14 15 16 17 18 19 20 21 22
EST 1HRLY 06 07 08 09 10 11 12 13 14 15 16 17
CRW CONSISTENCY H H H H M H H H H H H H
HTS CONSISTENCY H H H H H H H H H H H H
BKW CONSISTENCY H H H H L H H H H H H H
EKN CONSISTENCY H L L L L L M M H H H H
PKB CONSISTENCY M L L L M H H H H H H H
CKB CONSISTENCY M L M L L M H H H H H H
AFTER 12Z FRIDAY...
NO WIDESPREAD IFR EXPECTED.
&&
.RLX WATCHES/WARNINGS/ADVISORIES...
WV...NONE.
OH...NONE.
KY...NONE.
VA...NONE.
&&
$$
SYNOPSIS...JSH/MZ
NEAR TERM...JSH/ARJ
SHORT TERM...MZ
LONG TERM...TRM
AVIATION...JSH
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
510 AM CST THU DEC 26 2013
.SHORT TERM...(TODAY THROUGH FRIDAY)
ISSUED AT 335 AM CST THU DEC 26 2013
MAIN WEATHER HAPPENINGS WILL BE MORE LIGHT SNOW FOR TODAY...THEN
SOME MODERATION IN TEMPERATURES ON FRIDAY.
WATER VAPOR SATELLITE LOOP COUPLED WITH RAP 500MB ANALYSIS SHOWS THE
NATION DOMINATED BY A LONG WAVE TROUGH OF LOW PRESSURE WITH
NORTHWEST FLOW INTO THE UPPER MISSISSIPPI RIVER VALLEY REGION. AN
EMBEDDED SHORT WAVE TROUGH WAS MOVING INTO THE DAKOTAS EARLY THIS
MORNING...TOWARD OUR FORECAST AREA. MEANWHILE...IR SATELLITE/SURFACE
OBSERVATIONS SHOWING STRATUS CLOUDS ENSHROUDING THE REGION...TRAPPED
UNDER A WEAK RIDGE OF HIGH PRESSURE THAT EXTENDED FROM THE MID AND
UPPER MISSISSIPPI RIVER VALLEY REGIONS INTO NORTHERN MN. RADAR
MOSAIC AND SURFACE OBSERVATIONS SHOWING SOME LIGHT SNOW FLURRY
ACTIVITY ACROSS PORTIONS OF WEST CENTRAL WISCONSIN AND ACROSS CENTRAL
AND NORTHERN MN. LIGHT SNOW WAS FALLING WITH A BIT MORE FERVOR
ACROSS PORTIONS OF ND IN ADVANCE OF THAT MID-LEVEL TROUGH WITH SOME
VISIBILITY RESTRICTIONS IN THE 4-5SM RANGE.
WILL BE WATCHING THAT MID-LEVEL TROUGH MOVE FROM THE DAKOTAS INTO
OUR REGION BY MID-MORNING WITH DECENT ISENTROPIC LIFT DEPICTED BY
THE NAM AND RAP ON THE 275K SURFACE...OR MAINLY IN THE 900-800MB
LAYER. WILL LIKELY SEE SNOW AMOUNTS IN THE 1/2 TO 1 INCH RANGE
THROUGH THE DAY WITH THIS WAVE BEFORE IT DEPARTS SOUTHEAST BY THIS
EVENING. OTHERWISE...LOOK FOR HIGHS TODAY IN THE TEENS ACROSS NORTH
CENTRAL WI...TO THE MID/UPPER 20S ELSEWHERE.
SOME LINGERING VERY LIGHT SNOW MAY STILL BE SEEN THIS EVENING EAST
OF THE MISSISSIPPI ON THE TAIL END OF THE PASSING TROUGH...BUT THEN
CLOUDS ARE EXPECTED TO DECREASE AFTER MIDNIGHT FROM SOUTHWEST TO
NORTHEAST AS A WEAK RIDGE OF HIGH PRESSURE BUILDS IN BEHIND THE
DEPARTING WAVE.
MODERATING TEMPERATURES EXPECTED ON FRIDAY AS SOUTHWEST WINDS KICK
IN ON THE BACKSIDE OF THE DEPARTING HIGH AND IN ADVANCE OF LOW
PRESSURE MOVING ALONG THE U.S./CANADIAN BORDER. NAM AND ECMWF
BULLISH WITH 925MB TEMPERATURES WARMING INTO THE 0 TO +5C RANGE
WHEREAS THE GFS IS ONLY IN THE -2 TO +3C RANGE. MODEL CONSENSUS
YIELDS HIGHS IN THE UPPER 20S ACROSS CENTRAL WI...TO THE LOWER 30S
FOR AREAS SOUTHWEST OF THE I-94 CORRIDOR. HOWEVER...SOUTHWEST WINDS
IN THE 10-20MPH RANGE WILL MAKE IT FEEL MORE LIKE THE UPPER TEENS TO
LOWER 20S.
.LONG TERM...(FRIDAY NIGHT THROUGH NEW YEARS DAY)
ISSUED AT 335 AM CST THU DEC 26 2013
WARM AIR ADVECTION WILL CONTINUE FRIDAY NIGHT INTO SATURDAY AS THE
AREA REMAINS IN THE WARM SECTOR OF LOW PRESSURE MOVING ACROSS
SOUTHERN ONTARIO CANADA. LOOK FOR LOWS FRIDAY NIGHT IN THE LOW TO
MID 20S WITH HIGHS ON SATURDAY EXPECTED TO TOP OFF IN THE LOWER AND
MIDDLE 30S. AN ARCTIC COLD FRONT IS THEN SLATED TO DROP THROUGH THE
AREA SATURDAY NIGHT.
WILL HAVE TO KEEP AN EYE ON PRECIPITATION TYPE SATURDAY NIGHT AS THE
GFS BUFKIT SOUNDING HINTING AT LOW LEVEL SATURATION UP TO 800MB WITH
NO ICE PRESENT IN THE CLOUD AS THE FRONT MOVES IN. AS SUCH...ADDED
THE MENTION OF FREEZING DRIZZLE INTO THE WEATHER GRIDS ALONG WITH
THE CHANCE OF LIGHT SNOW. BY EARLY SUNDAY MORNING...IT APPEARS THE
SATURATED COLUMN WILL HAVE ICE PRESENT FOR ALL LIGHT SNOW.
BY SUNDAY MORNING...PLAN ON TEMPERATURES DROPPING INTO THE SINGLE
DIGITS AND TEENS ABOVE ZERO WITH ONLY A 2 TO 3 DEGREE RISE DURING
THE DAY SUNDAY. SOME LIGHT SNOW WILL STILL BE POSSIBLE MAINLY EAST OF
THE MISSISSIPPI RIVER. BRISK NORTHWEST WINDS WILL ADD TO THE CHILL
SUNDAY AS WELL WITH WIND CHILL VALUES FALLING INTO THE -15 TO
-25 DEGREE RANGE ACROSS SOUTHEAST MN/NORTHEAST IA IN
THE AFTERNOON.
VERY COLD WIND CHILLS WILL BE SEEN SUNDAY NIGHT...LASTING THROUGH
TUESDAY MORNING//COLDEST EARLY MONDAY MORNING// AS THE ARCTIC AIR
CONTINUES TO SPILL INTO THE REGION. WIND CHILL HEADLINES WILL LIKELY
BE NEEDED. LOWEST WIND CHILL VALUES MONDAY MORNING COULD BE AS LOW
AS -25 TO -35 DEGREES. SLIGHT MODERATION IN TEMPERATURES MAY BE SEEN
LATER TUESDAY THROUGH WEDNESDAY AS THE HEART OF THE ARCTIC AIR MOVES
MORE INTO THE GREAT LAKES REGION.
EMBEDDED SHORTWAVE TROUGHS EMBEDDED IN THE NORTHWEST FLOW WILL ALSO
GIVE THE AREA PERIODIC LIGHT SNOW CHANCES FROM MONDAY NIGHT THROUGH
WEDNESDAY.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z THURSDAY NIGHT)
ISSUED AT 510 AM CST THU DEC 26 2013
-SN CONTINUES TO FALL ALONG AND NORTH OF A SFC WARM
FRONT...GENERALLY RUNNING NEAR THE MISSISSIPPI RIVER...WITH THE HELP
OF SOME LOW LEVEL ISENTROPIC UPGLIDE. RADAR TRENDS HAVE THIS
SHIFTING AWAY FROM THE TAF SITES. LOW MVFR CIGS ALSO MOSTLY ALONG
AND EAST OF THE FRONT...WITH SATELLITE TRENDS ALSO SUPPORTING
KEEPING THESE LOWER CLOUDS AWAY FROM KRST/KLSE. WILL FOLLOW THESE
TRENDS.
WEAK UPPER LEVEL DISTURBANCE SLATED TO TRACK ACROSS THE NORTHERN
PLAINS AND ACROSS THE LOCAL AREA THIS AFTERNOON. SOME -SN ASSOCIATED
WITH THIS...BUT CURRENT VSBY RESTRICTIONS WERE MOSTLY 4SM OR
GREATER. CIGS WERE A MIX OF MVFR/VFR. RAP/ARW/NAM12 TRENDS SEEM TO
FAVOR A DECREASE IN -SN COVERAGE/INTENSITY AS IT MOVES IN...SO
CONFIDENCE NOT HIGH THAT THERE WILL BE A PERIOD OF IFR CONDITIONS AS
THE SHORTWAVE MOVES THROUGH. SOME MVFR CIGS ARE MORE
LIKELY...ALTHOUGH HOW LONG THESE HANG AROUND IS UNCERTAIN. BUFKIT
SOUNDINGS HOLD ONTO A LOW SATURATION THROUGH MUCH OF TONIGHT...BUT
NOT SOLD THIS IS REALISTIC. WILL GO PESSIMISTIC AND HANG ONTO THE
MVFR CIGS THROUGH THIS EVENING FOR NOW...WITH HIGH VFR CLOUDS
OVERNIGHT.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...DAS
LONG TERM....DAS
AVIATION.....RIECK
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
419 PM CST THU DEC 26 2013
.DISCUSSION...
418 PM CST
MAIN CONCERN FOR THE NEXT SEVERAL DAYS WILL BE THE TEMPERATURE
FORECAST WHICH WILL BE THE TEMPERATURE FORECAST WHICH WILL FEATURE
UNSEASONABLE WARM CONDITIONS FOLLOWED BY AN ARCTIC BLAST.
FOR THE REMAINDER OF THE AFTERNOON AND INTO THIS EVENING WARM
ADVECTION AT THE SURFACE IS OVERCOMING INCREASING CLOUD COVER WITH
TEMPERATURES APPROACHING 40F OVER THE PONTIAC METRO AREA AND WITH
TEMPERATURES DROPPING OFF TO THE NORTH WHERE GREATER SNOWCOVER IS IN
PLACE. LATEST LOOKS OUT THE WINDOW HERE IN ROMEOVILLE SHOW THAT THE
WARM/MOIST ADVECTION AT THE SURFACE IS ALREADY EFFICIENTLY MELTING
THE SNOWCOVER...WHICH WILL HAVE A SIGNIFICANT IMPACT ON THE
TEMPERATURE FORECAST FOR FRIDAY AND SATURDAY.
THE MODELS HAVE BEEN TRENDING WARMER WITH RECENT RUNS BUT STILL FEEL
THAT THE FORECAST SFC MAX TEMPS ARE STILL SIGNIFICANTLY UNDERDONE
DUE TO INADEQUATELY HANDLING THE SNOW MELT. SO...FOR FRIDAY AND
SATURDAY...HAVE SIGNIFICANTLY RAISED MAX TEMPS OVER GUIDANCE. FOR
THE NEXT FEW DAYS...HAVE BEEN LARGELY FOLLOWING THE ECMWF TRENDS
THOUGH THERE ARE NO SIGNIFICANT DIFFERENCES AMONG THE MODELS WITH
TEMPERATURES ALOFT. ON SATURDAY...AT THE 925MB LEVEL...A WEDGE OF
VERY WARM AIR WITH TEMPS OF +2 TO +4C OVERSPREADS THE AREA WHILE BY
SATURDAY THE 925MB TEMPS ARE ADVERTISED IN THE +6 TO +8C.
ALSO...THE DEWPOINT TREND WILL BE UPWARDS AS WELL WITH MIDDLE TO
UPPER 20S FRIDAY AND LOWER TO MIDDLE 30S BY SATURDAY. SO...FEEL
THAT THE ONGOING AND CONTINUED WARM...MOIST ADVECTION WILL MELT OFF
MUCH OR ALL OF THE SNOW COVER...WHICH WILL IN TURN...HELP ENHANCE
THE TEMPERATURE TREND. LATEST THINKING IS THAT HIGHS ON FRIDAY WILL
RANGE FROM THE LOWER 30S OVER THE ROCKFORD AREA...WHERE THE
SNOWCOVER SHOULD LINGER LONGEST...WHILE THE PONTIAC AREA SHOULD
REACH THE LOWERS 40S. THE CHICAGO METRO AND NWRN INDIANA SHOULD BE
IN BETWEEN THIS RANGE WITH HIGHS IN THE MIDDLE TO UPPER 30S...THOUGH
GETTING CLOSE TO 40F IS NOT OUT OF THE REALM OF POSSIBILITY. THE
GREATEST WARMING IS STILL EXPECTED FOR SATURDAY. HAVE BUMPED TEMPS
WITH HIGHS IN THE LOW 50S OVER THE FAR SERN PORTIONS OF THE
CWA...GENERALLY SOUTH OF A LINE FROM RENSSELAER TO
FAIRBURY...DROPPING OFF INTO THE MIDDLE TO UPPER 40S FROM CHICAGO TO
PERU. STILL ANTICIPATE THAT THE ROCKFORD AREA SHOULD LINGER IN THE
UPPER 30S AS THE AXIS OF THE HIGHEST 925MB TEMPS WILL EXTEND FROM
THAT CHICAGO TO PERU LINE. HOWEVER...GIVEN THE UNUSUALLY STRONG
WARM/MOIST ADVECTION AND AMPLE SUNSHINE UNDER MOSTLY SUNNY
SKIES...THERE IS STILL A CHANCE THAT THE FORECAST WARMING TREND
COULD BE A LITTLE CONSERVATIVE AND THAT TEMPS COULD STILL END UP
BEING A LITTLE HIGHER.
AND THEN COMES THE SLAP IN THE FACE. A STRONG COLD FRONT WILL PUSH
THROUGH THE AREA THROUGH THE DAY ON SUNDAY...USHERING IN LARGE AREA
OF ARCTIC HIGH PRESSURE. THE TEMPERATURE TREND FOR SUNDAY WILL BE A
LITTLE TRICKY AS HIGHS WILL LIKELY COME EARLY IN THE MORNING AND
TEMPERATURES WILL DROP OFF THROUGH THE DAY. GIVEN THAT THERE COULD
STILL BE SOME LINGERING LOW LEVEL MOISTURE IN PLACE AHEAD OF THE
FRONT...THERE WILL BE A CHANCE FOR SOME LIGHT SNOW OR SNOWSHOWERS
ALONG AND JUST BEHIND THE FRONT...BUT THE COLD...DRY AIR WILL
QUICKLY OVERSPREAD THE AREA AND ANY PCPN POTENTIAL SHOULD SHUT OFF
RELATIVELY QUICKLY. BY MONDAY MORNING TEMPERATURES OVER MUCH OF THE
CWA WILL DROP BELOW 0F...WITH ONLY LOCATIONS SOUTH AND EAST OF A
PONTIAC TO CHICAGO LINE REMAINING A LITTLE ABOVE 0F. EVEN WITH AMPLE
SUNSHINE...TEMPERATURES ON MONDAY SHOULD REMAIN IN THE SINGLE DIGITS
NORTH OF A LINE FROM CHICAGO TO PONTIAC...WHILE THE REMAINDER OF THE
CWA WILL ONLY PERHAPS REACH THE LOWER TEENS.
FOR THE REMAINDER OF THE FORECAST PERIOD...FROM TUESDAY THROUGH
THURSDAY WILL REMAIN SIGNIFICANTLY BELOW NORMAL WITH LITTLE TO NO
CHANCES FOR PRECIPITATION. AGAIN...HAVE UNDERCUT GUIDANCE WITH
RESPECT TO TEMPERATURES IN THE EXTENDED FORECAST AND TRENDED CLOSER
TO THE WPC MEDIUM RANGE TEMPERATURE GUIDANCE. TEMPERATURES SHOULD
HOLD STEADY THROUGH WEDNESDAY WITH SINGLE DIGITS TO LOWER TEENS
ABOVE 0F FOR HIGHS AND LOWS APPROACHING -10F OVER THE NWRN PORTIONS
OF THE CWA...AND LOWER SINGLE DIGITS ABOVE 0F OVER THE FAR SERN
PORTIONS OF THE CWA. BY FRIDAY THERE MAY BE SOME MODERATION...BUT
TEMPS ARE STILL EXPECTED TO REMAIN A LITTLE BELOW NORMAL.
KREIN
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 22Z...
* DIMINISHING POTENTIAL FOR LIGHT SNOW/FLURRIES INTO EARLY
EVENING.
* CIG TRENDS...AND POTENTIAL FOR MVFR TO RETURN THIS EVENING AND
OVERNIGHT.
RC
//DISCUSSION...UPDATED 22Z...
IT APPEARS THAT THERE IS A MUCH MORE STOUT DRY LAYER THAN
EXPECTED AT THE LOWER LEVELS OF THE ATMOSPHERE. DESPITE AN UPPER
LEVEL DISTURBANCE APPROACHING...THIS IS PREVENTING AND SHOULD
CONTINUE TO PREVENT MOST IF NOT ALL OF THE -SN FROM REACHING THE
SURFACE. PULLED MENTION FROM TAF...BUT EVEN IF FLURRIES
OCCUR...THEY SHOULDNT HAVE ANY OPERATIONAL IMPACT. FOR CIG
TRENDS...NO SIGNS OF LOWERING UPSTREAM OVER IA AND SW WI...SO ITS
ALSO POSSIBLE THAT THE LOW-MID MVFR CIGS WILL AT LEAST BE SLOW TO
MATERIALIZE IF THEY OCCUR AT ALL.
...FROM 18Z...
BAND OF SNOW IS EXITING EAST OF THIS CHICAGO TERMINALS THIS
AFTERNOON BUT A PAIR OF ADDITIONAL UPPER LEVEL DISTURBANCES TO THE
NORTHWEST WILL BRING ADDITIONAL CHANCES FOR SNOW THROUGH PORTIONS
OF THE AFTERNOON AND EVENING. THE FIRST WAVE IS CURRENTLY
DROPPING SOUTHEAST ACROSS IOWA WITH RADAR RETURNS ACROSS MUCH OF
THE EASTERN HALF OF IOWA AND NORTHWEST ILLINOIS. PER SURFACE OBS
HOWEVER...MOST OF THIS IS NOT REACHING THE GROUND...AND APPEARS
THE MAIN FORCING WILL DROP SOUTH OF THE TERMINALS EARLY THIS
AFTERNOON. THE NEXT WAVE IS OVER THE EASTERN DAKOTAS EARLY THIS
AFTERNOON AND WILL TAKE AIM AT THE IL/WI STATE LINE LATE THIS
AFTERNOON AND THIS EVENING. MOST MODELS INDICATE THAT THE
ACCUMULATING SNOWFALL WILL FALL NORTH OF THE TERMINALS...HOWEVER
SOME LIFT IS NOTED AS FAR SOUTH AS THE TERMINALS. ITS NOT CO-
LOCATED WELL WITH THE MOISTURE OR THE SNOW GROWTH ZONE...SO DO NOT
ANTICIPATE EFFICIENT SNOW PRODUCTION WITH THIS WAVE.
INSTEAD...EXPECT A PERIOD OF FLURRIES WITH GENERALLY VFR
CONDITIONS...THOUGH CANNOT RULE OUT PERHAPS A PERIODIC BRIEF DROPS
TO MVFR VSBY. WILL MONITOR UPSTREAM TRENDS THIS AFTERNOON TO
DETERMINE IF THE THREAT IS ENOUGH TO INCLUDE IN TAF.
THERE IS A WEAK SURFACE REFLECTION OF THE SECOND WAVE THIS EVENING.
SSW TO SW WINDS AHEAD OF THE SURFACE TROUGH WILL VEER TO THE WSW OR
WEST FOR A PERIOD THIS EVENING. BEHIND THIS SLIGHT WIND
SHIFT...FORECAST SOUNDINGS SHOW SATURATION OF THE LOWER LEVELS
INDICATING THE DEVELOPMENT OF MVFR OR IN SOME CASES IFR CIGS. MET
GUIDANCE INDICATES A SIMILAR DROP IN CIGS OVERNIGHT...WHILE MAV/LAV
GUIDANCE DOES NOT. WILL INTRODUCE MVFR CIGS INTO THE FORECAST...BUT
AM CONCERNED THAT LOWER CIGS ARE POSSIBLE. RAP LOW LEVEL MOISTURE
FIELDS INDICATE THESE CIGS WILL DEVELOP NEAR THE MISSISSIPPI RIVER
MID TO LATE THIS AFTERNOON...SO WILL GAIN MORE CONFIDENCE IN CIG
TRENDS BY THEN.
BMD
//ORD AND MDW CONFIDENCE...UPDATED 22Z...
* HIGH CONFIDENCE THAT IF ANY FLURRIES OCCUR THROUGH EARLY
EVENING...THERE WILL BE NO OPERATIONAL IMPACT.
* LOW CONFIDENCE IN CIG TRENDS THIS EVENING/OVERNIGHT REGARDING
DEVELOPMENT OF MVFR CIGS.
RC
//OUTLOOK FOR ORD/MDW FOR 00Z SATURDAY-12Z THURSDAY...UPDATED 12Z...
FRIDAY NIGHT...VFR WIND.
SATURDAY...VFR WIND.
SUNDAY THROUGH TUESDAY NIGHT...PERIODS OF -SN WITH OCNL MVFR
CIGS/VSBY. A PERIOD OF IFR CIGS/VIS POSSIBLE.
WEDNESDAY...VFR WX NIL.
ED F
&&
.MARINE...
232 PM...A WEAK RIDGE CURRENTLY OVER THE WESTERN LAKES REGION
WILL DRIFT SOUTHEAST TONIGHT AND BE ABSORBED BY A MUCH LARGER AND
STRONGER HIGH OVER THE OHIO VALLEY. A FAST MOVING LOW WILL MOVE
ACROSS CENTRAL ONTARIO AND THE NORTHERN LAKES FRIDAY. THE GRADIENT
WILL TIGHTEN BETWEEN THIS APPROACHING LOW AND THE STRONG HIGH TO
THE SOUTH WITH GALES POSSIBLE ESPECIALLY ACROSS THE NORTHERN HALF
OF LAKE MICHIGAN. OVERALL DURATION PERHAPS 6 TO 9 HOURS AND HAVE
HOISTED A GALE WATCH FOR FRIDAY AFTERNOON/FRIDAY EVENING. AS THE
LOW LIFTS NORTHEAST INTO QUEBEC FRIDAY NIGHT...THE GRADIENT WILL
WEAKEN AND WHILE ITS POSSIBLE THERE COULD BE SOME GALE GUSTS ON
THE SOUTH HALF OF THE LAKE...CONFIDENCE DECREASES FURTHER SOUTH
AND HAVE HELD WINDS AT 30 KTS. A TRAILING COLD FRONT FROM THIS LOW
WILL SAG SOUTH ACROSS NORTHERN LAKE MICHIGAN SATURDAY EVENING WITH
NEW LOW PRESSURE FORMING OF THE PLAINS SATURDAY AND THEN MOVING
EAST/NORTHEAST ALONG THIS FRONT SATURDAY NIGHT INTO SUNDAY
MORNING. THIS WILL LIKELY SLOW THE FRONT/S PROGRESS SOUTH DOWN
LAKE MICHIGAN WITH SOUTHWESTERLY FLOW EXPECTED AHEAD OF THE FRONT
SATURDAY NIGHT. THE GRADIENT WILL TIGHTEN SHARPLY BEHIND THE FRONT
AND COMBINED WITH STRONG COLD AIR SPREADING ACROSS THE REGION...
NORTHERLY WINDS SHOULD EASILY INCREASE TO 30 KTS AND ITS POSSIBLE
FOR A PERIOD OF LOW END GALES. NORTHERLY WINDS WILL SLOWLY TURN
NORTHWEST SUNDAY INTO MONDAY AND GRADUALLY DIMINISH. CMS
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...GALE WATCH...LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-LMZ565-LMZ567-
LMZ868...NOON FRIDAY TO MIDNIGHT SATURDAY.
&&
$$
VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)
FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/US.NATIONALWEATHERSERVICE.CHICAGO.GOV
WWW.TWITTER.COM/NWSCHICAGO
WWW.YOUTUBE.COM/NWSCHICAGO
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
416 PM CST THU DEC 26 2013
.DISCUSSION...
930 AM CST
HAVE MADE SOME MINOR ADJUSTMENTS TO THE WX/POP/QPS FOR THE REST OF
THIS MORNING AND INTO THIS AFTERNOON. A SERIES OF SHORTWAVES
RIPPLING THROUGH THE FAST NORTHWEST FLOW ALOFT ARE ALREADY
GENERATING SOME LIGHT SNOW ACROSS NRN IL. THE LATEST GUIDANCE AND
UPSTREAM SATELLITE IMAGERY SUGGEST THAT A COUPLE MORE ORGANIZED
SHORTWAVES WILL TRAVERSE THE NRN PORTIONS OF THE CWA THIS
AFTERNOON. SO HAVE BUMPED UP POPS FOR THE REMAINDER OF TODAY.
WHILE THIS LOOKS TO BE MORE OF A HIGHER POP...LOWER QPF
SITUATION...WILL STILL CARRY MEASURABLE PCPN FOR THIS AFTERNOON...
BUT GIVEN THE EXPECTATIONS OF RELATIVELY HIGH SNOW TO LIQUID RATIO
LIKELY...ANY SNOWFALL WOULD MOST LIKELY BE OBSERVED AS A DUSTING
AND DIFFICULT TO ACTUALLY MEASURE.
KREIN
.PREVIOUS DISCUSSION...
335 AM CST
SYNOPSIS...LIGHT SNOW IS POSSIBLE THIS AFTERNOON ALONG THE IL/WI
STATE LINE...THEN THE WARM UP IS ON THROUGH SATURDAY. TEMPS CRASH
BEHIND THE LOW SUNDAY WITH VERY COLD AIR RETURNING TO THE REGION.
SNOW IS POSSIBLE ON SUNDAY BUT THE BETTER CHANCE LOOKS TO BE MONDAY
NIGHT INTO TUESDAY.
TODAY AND TONIGHT...
THE UPPER LEVEL TROUGH AXIS HAS PUSHED EAST OF THE AREA ALONG WITH
THE SNOW WE SAW LAST NIGHT. AT THE SURFACE...WEAK LOW PRESSURE IS
OVER SOUTHWESTERN ONTARIO. HIGH PRESSURE IS CENTERED OVER TEXARKANA
BUT ITS RIDGE EXTENDS NORTH THROUGH THE MISSISSIPPI RIVER VALLEY.
THE RIDGE WILL MOVE OVERHEAD THIS MORNING WHILE THE MAIN HIGH
REMAINS TO OUR SOUTH.
A WEAK SHORTWAVE PASSES THROUGH WI THIS AFTN KICKING OFF SNOW
SHOWERS. THE MAIN VORT WILL BE OVER CENTRAL WI SO THINKING THE
MAJORITY OF PRECIP WILL BE OVER WI...BUT COULD SEE A HALF INCH OR
LESS ALONG THE IL/WI STATE LINE. MODEL SOUNDINGS SUPPORT THIS AS
THEY SHOW OMEGA REMAINING LOWER THAN THE SATURATED DGZ LAYER. THEN
AS OMEGA LIFTS INTO THE SATURATED LAYER...THE OMEGA WEAKENS GREATLY
AND THE SATURATION ALSO WEAKENS.
WINDS TURN SW AND WEAK WAA WILL LEAD TO HIGH TEMPS IN THE MID TO
UPPER 20S. FAR SOUTHERN AREAS IN THE CWA MAY EVEN MAKE OR BREAK
FREEZING AS THEY DO NOT HAVE ANY SNOW ON THE GROUND AND WILL SEE
SOME SUN. WAA CONTINUES THROUGH TONIGHT...BUT THE SNOWPACK WILL
WREAK HAVOC WITH LOW TEMPS. WINDS LIGHTEN DUE TO THE BAGGY PRESSURE
PATTERN AND CLOUDS THIN OVERNIGHT. THE GOING LOW TEMPS LOOKED VERY
REASONABLE...THEREFORE DID NOT MAKE ANY MAJOR CHANGES. HAVE TEENS
OVER NORTH CENTRAL IL AND THEN LOW 20S IN THE SOUTHEAST CORNER OF
THE CWA.
FRIDAY AND SATURDAY...
UPPER LEVEL FLOW TURNS ZONAL THROUGH SATURDAY AND WAA REALLY KICKS
INTO HIGH GEAR FRIDAY AND SATURDAY. A LOW PASSES WELL TO OUR
NORTH...BUT WITH THE HIGH OVER THE GULF COAST...THE PRESSURE
GRADIENT TIGHTENS AND WINDS PICK UP. SW WINDS AROUND 10 KT WITH
GUSTS 15 TO 20 KT WILL HELP USHER IN THE WARMER AIR. GUIDANCE HAS
925MB TEMPS RISING TO +4C BY FRIDAY EVENING AND THEN TO +6 TO +8 BY
SATURDAY EVENING. AS SUCH RAISED TEMPS FRIDAY...FRIDAY NIGHT...AND
SATURDAY. CONFIDENCE IS MEDIUM-HIGH IN THE GOING FORECAST TEMPS FOR
THAT PERIOD.
FOR NOW CONTINUED THE TREND THAT THE END OF THIS WEEK LOOKS ABOVE
NORMAL IN THE TEMP DEPARTMENT. HOW WARM...NOT SURE. FOR AREAS WITH
LITTLE SNOW...ROUGHLY AREAS ALONG AND SOUTH OF I-88...THE WARM UP
COULD BE WARMER THAN CURRENTLY FORECAST. FOR NOW THINKING ABOVE
FREEZING ON FRIDAY AND 40S ON SATURDAY SEEM REASONABLE. FOR AREAS
NORTH OF I-88 THAT HAVE A DECENT SNOW PACK...THINGS COULD BE MORE
DICEY. RFD FOR INSTANCE HAS 7 INCHES OF SNOW ON THE GROUND...AND
THE WAA ADVECTION AND NEAR FREEZING TEMPS ON FRIDAY MAY NOT MAKE A
SIGNIFICANT DENT IN THE SNOW. AS SUCH WENT NEAR GUIDANCE FOR
THESE NORTHERN AREAS WITH TEMPS JUST ABOVE FREEZING FRIDAY...AND
AROUND 40 SATURDAY. COULD CERTAINLY SEE A TIGHT TEMP GRADIENT
WITHIN THE CWA AS THE SNOW FREE AREAS WARM QUICKLY...WHILE THE AREAS
WITH SNOW PACK STRUGGLE TO CLIMB.
EXTENDED...SUNDAY THROUGH TUESDAY...
THE SURFACE LOW SINKS SOUTH...MOVING OVER THE CWA SATURDAY NIGHT
INTO SUNDAY. AN UPPER LEVEL STREAMER ASSOCIATED WITH THE LOW
WEAKENS AS THE STRONGER UPPER LEVEL TROUGH CATCHES UP WITH THE LOW.
PRECIP IS EXPECTED ALONG AND BEHIND THE COLD FRONT. GUIDANCE
DIFFERS A BIT ON THE TIMING OF THE LOW AND AS TO HOW MUCH FORCING
WILL ACCOMPANY IT. THE GFS IS MORE VIGOROUS THAN THE ECMWF WITH
PRECIP...WHILE THE ECMWF IS A BIT FASTER. AS SUCH LEFT POPS IN THE
CHANCE RANGE UNTIL THE FORCING AND TIMING ASPECTS BECOME A BIT
CLEARER. OVERALL NOT EXPECTING A LOT OF PRECIP/SNOW.
THE BIGGER STORY WILL BE TEMPS. TEMPS WILL FALL SUNDAY AS COLD AIR
CONTINUES TO FUNNEL IN BEHIND THE TROUGH AXIS. 925MB TEMPS FALL TO
-4 TO -14C ALOFT BY SUNDAY EVENING WITH COLDER AIR EXPECTED
OVERNIGHT. HIGH PRESSURE ALSO APPROACHES FROM THE WEST SO CLEARING
SKIES AND NORTHWEST WINDS AROUND 10 KT WILL LEAD TO A VERY COLD
NIGHT. LOW TEMPS WILL RANGE FROM BELOW ZERO OVER NORTH CENTRAL IL TO
SINGLE DIGITS OVER NW INDIANA. MIN WIND CHILLS BELOW -20 ARE STILL
EXPECTED ACROSS NORTH CENTRAL IL SUNDAY NIGHT AND MONDAY NIGHT.
COLD CONTINUES THROUGH NEW YEARS EVE WITH A SLIGHT RELIEF EXPECTED
ON JAN 1ST. GUIDANCE CONTINUES TO HINT AT A PRECIP SYSTEM
TUESDAY...BUT GUIDANCE IS LESS CLEAR ON FORCING AND TIMING TODAY
COMPARED TO YESTERDAY. THEREFORE LEFT SLIGHT CHANCE TO CHANCE POPS
IN THROUGH MID WEEK.
JEE
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 22Z...
* DIMINISHING POTENTIAL FOR LIGHT SNOW/FLURRIES INTO EARLY
EVENING.
* CIG TRENDS...AND POTENTIAL FOR MVFR TO RETURN THIS EVENING AND
OVERNIGHT.
RC
//DISCUSSION...UPDATED 22Z...
IT APPEARS THAT THERE IS A MUCH MORE STOUT DRY LAYER THAN
EXPECTED AT THE LOWER LEVELS OF THE ATMOSPHERE. DESPITE AN UPPER
LEVEL DISTURBANCE APPROACHING...THIS IS PREVENTING AND SHOULD
CONTINUE TO PREVENT MOST IF NOT ALL OF THE -SN FROM REACHING THE
SURFACE. PULLED MENTION FROM TAF...BUT EVEN IF FLURRIES
OCCUR...THEY SHOULDNT HAVE ANY OPERATIONAL IMPACT. FOR CIG
TRENDS...NO SIGNS OF LOWERING UPSTREAM OVER IA AND SW WI...SO ITS
ALSO POSSIBLE THAT THE LOW-MID MVFR CIGS WILL AT LEAST BE SLOW TO
MATERIALIZE IF THEY OCCUR AT ALL.
...FROM 18Z...
BAND OF SNOW IS EXITING EAST OF THIS CHICAGO TERMINALS THIS
AFTERNOON BUT A PAIR OF ADDITIONAL UPPER LEVEL DISTURBANCES TO THE
NORTHWEST WILL BRING ADDITIONAL CHANCES FOR SNOW THROUGH PORTIONS
OF THE AFTERNOON AND EVENING. THE FIRST WAVE IS CURRENTLY
DROPPING SOUTHEAST ACROSS IOWA WITH RADAR RETURNS ACROSS MUCH OF
THE EASTERN HALF OF IOWA AND NORTHWEST ILLINOIS. PER SURFACE OBS
HOWEVER...MOST OF THIS IS NOT REACHING THE GROUND...AND APPEARS
THE MAIN FORCING WILL DROP SOUTH OF THE TERMINALS EARLY THIS
AFTERNOON. THE NEXT WAVE IS OVER THE EASTERN DAKOTAS EARLY THIS
AFTERNOON AND WILL TAKE AIM AT THE IL/WI STATE LINE LATE THIS
AFTERNOON AND THIS EVENING. MOST MODELS INDICATE THAT THE
ACCUMULATING SNOWFALL WILL FALL NORTH OF THE TERMINALS...HOWEVER
SOME LIFT IS NOTED AS FAR SOUTH AS THE TERMINALS. ITS NOT CO-
LOCATED WELL WITH THE MOISTURE OR THE SNOW GROWTH ZONE...SO DO NOT
ANTICIPATE EFFICIENT SNOW PRODUCTION WITH THIS WAVE.
INSTEAD...EXPECT A PERIOD OF FLURRIES WITH GENERALLY VFR
CONDITIONS...THOUGH CANNOT RULE OUT PERHAPS A PERIODIC BRIEF DROPS
TO MVFR VSBY. WILL MONITOR UPSTREAM TRENDS THIS AFTERNOON TO
DETERMINE IF THE THREAT IS ENOUGH TO INCLUDE IN TAF.
THERE IS A WEAK SURFACE REFLECTION OF THE SECOND WAVE THIS EVENING.
SSW TO SW WINDS AHEAD OF THE SURFACE TROUGH WILL VEER TO THE WSW OR
WEST FOR A PERIOD THIS EVENING. BEHIND THIS SLIGHT WIND
SHIFT...FORECAST SOUNDINGS SHOW SATURATION OF THE LOWER LEVELS
INDICATING THE DEVELOPMENT OF MVFR OR IN SOME CASES IFR CIGS. MET
GUIDANCE INDICATES A SIMILAR DROP IN CIGS OVERNIGHT...WHILE MAV/LAV
GUIDANCE DOES NOT. WILL INTRODUCE MVFR CIGS INTO THE FORECAST...BUT
AM CONCERNED THAT LOWER CIGS ARE POSSIBLE. RAP LOW LEVEL MOISTURE
FIELDS INDICATE THESE CIGS WILL DEVELOP NEAR THE MISSISSIPPI RIVER
MID TO LATE THIS AFTERNOON...SO WILL GAIN MORE CONFIDENCE IN CIG
TRENDS BY THEN.
BMD
//ORD AND MDW CONFIDENCE...UPDATED 22Z...
* HIGH CONFIDENCE THAT IF ANY FLURRIES OCCUR THROUGH EARLY
EVENING...THERE WILL BE NO OPERATIONAL IMPACT.
* LOW CONFIDENCE IN CIG TRENDS THIS EVENING/OVERNIGHT REGARDING
DEVELOPMENT OF MVFR CIGS.
RC
//OUTLOOK FOR ORD/MDW FOR 00Z SATURDAY-12Z THURSDAY...UPDATED 12Z...
FRIDAY NIGHT...VFR WIND.
SATURDAY...VFR WIND.
SUNDAY THROUGH TUESDAY NIGHT...PERIODS OF -SN WITH OCNL MVFR
CIGS/VSBY. A PERIOD OF IFR CIGS/VIS POSSIBLE.
WEDNESDAY...VFR WX NIL.
ED F
&&
.MARINE...
232 PM...A WEAK RIDGE CURRENTLY OVER THE WESTERN LAKES REGION
WILL DRIFT SOUTHEAST TONIGHT AND BE ABSORBED BY A MUCH LARGER AND
STRONGER HIGH OVER THE OHIO VALLEY. A FAST MOVING LOW WILL MOVE
ACROSS CENTRAL ONTARIO AND THE NORTHERN LAKES FRIDAY. THE GRADIENT
WILL TIGHTEN BETWEEN THIS APPROACHING LOW AND THE STRONG HIGH TO
THE SOUTH WITH GALES POSSIBLE ESPECIALLY ACROSS THE NORTHERN HALF
OF LAKE MICHIGAN. OVERALL DURATION PERHAPS 6 TO 9 HOURS AND HAVE
HOISTED A GALE WATCH FOR FRIDAY AFTERNOON/FRIDAY EVENING. AS THE
LOW LIFTS NORTHEAST INTO QUEBEC FRIDAY NIGHT...THE GRADIENT WILL
WEAKEN AND WHILE ITS POSSIBLE THERE COULD BE SOME GALE GUSTS ON
THE SOUTH HALF OF THE LAKE...CONFIDENCE DECREASES FURTHER SOUTH
AND HAVE HELD WINDS AT 30 KTS. A TRAILING COLD FRONT FROM THIS LOW
WILL SAG SOUTH ACROSS NORTHERN LAKE MICHIGAN SATURDAY EVENING WITH
NEW LOW PRESSURE FORMING OF THE PLAINS SATURDAY AND THEN MOVING
EAST/NORTHEAST ALONG THIS FRONT SATURDAY NIGHT INTO SUNDAY
MORNING. THIS WILL LIKELY SLOW THE FRONT/S PROGRESS SOUTH DOWN
LAKE MICHIGAN WITH SOUTHWESTERLY FLOW EXPECTED AHEAD OF THE FRONT
SATURDAY NIGHT. THE GRADIENT WILL TIGHTEN SHARPLY BEHIND THE FRONT
AND COMBINED WITH STRONG COLD AIR SPREADING ACROSS THE REGION...
NORTHERLY WINDS SHOULD EASILY INCREASE TO 30 KTS AND ITS POSSIBLE
FOR A PERIOD OF LOW END GALES. NORTHERLY WINDS WILL SLOWLY TURN
NORTHWEST SUNDAY INTO MONDAY AND GRADUALLY DIMINISH. CMS
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...GALE WATCH...LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-LMZ565-LMZ567-
LMZ868...NOON FRIDAY TO MIDNIGHT SATURDAY.
&&
$$
VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)
FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/US.NATIONALWEATHERSERVICE.CHICAGO.GOV
WWW.TWITTER.COM/NWSCHICAGO
WWW.YOUTUBE.COM/NWSCHICAGO
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
232 PM CST THU DEC 26 2013
.DISCUSSION...
930 AM CST
HAVE MADE SOME MINOR ADJUSTMENTS TO THE WX/POP/QPS FOR THE REST OF
THIS MORNING AND INTO THIS AFTERNOON. A SERIES OF SHORTWAVES
RIPPLING THROUGH THE FAST NORTHWEST FLOW ALOFT ARE ALREADY
GENERATING SOME LIGHT SNOW ACROSS NRN IL. THE LATEST GUIDANCE AND
UPSTREAM SATELLITE IMAGERY SUGGEST THAT A COUPLE MORE ORGANIZED
SHORTWAVES WILL TRAVERSE THE NRN PORTIONS OF THE CWA THIS
AFTERNOON. SO HAVE BUMPED UP POPS FOR THE REMAINDER OF TODAY.
WHILE THIS LOOKS TO BE MORE OF A HIGHER POP...LOWER QPF
SITUATION...WILL STILL CARRY MEASURABLE PCPN FOR THIS AFTERNOON...
BUT GIVEN THE EXPECTATIONS OF RELATIVELY HIGH SNOW TO LIQUID RATIO
LIKELY...ANY SNOWFALL WOULD MOST LIKELY BE OBSERVED AS A DUSTING
AND DIFFICULT TO ACTUALLY MEASURE.
KREIN
.PREVIOUS DISCUSSION...
335 AM CST
SYNOPSIS...LIGHT SNOW IS POSSIBLE THIS AFTERNOON ALONG THE IL/WI
STATE LINE...THEN THE WARM UP IS ON THROUGH SATURDAY. TEMPS CRASH
BEHIND THE LOW SUNDAY WITH VERY COLD AIR RETURNING TO THE REGION.
SNOW IS POSSIBLE ON SUNDAY BUT THE BETTER CHANCE LOOKS TO BE MONDAY
NIGHT INTO TUESDAY.
TODAY AND TONIGHT...
THE UPPER LEVEL TROUGH AXIS HAS PUSHED EAST OF THE AREA ALONG WITH
THE SNOW WE SAW LAST NIGHT. AT THE SURFACE...WEAK LOW PRESSURE IS
OVER SOUTHWESTERN ONTARIO. HIGH PRESSURE IS CENTERED OVER TEXARKANA
BUT ITS RIDGE EXTENDS NORTH THROUGH THE MISSISSIPPI RIVER VALLEY.
THE RIDGE WILL MOVE OVERHEAD THIS MORNING WHILE THE MAIN HIGH
REMAINS TO OUR SOUTH.
A WEAK SHORTWAVE PASSES THROUGH WI THIS AFTN KICKING OFF SNOW
SHOWERS. THE MAIN VORT WILL BE OVER CENTRAL WI SO THINKING THE
MAJORITY OF PRECIP WILL BE OVER WI...BUT COULD SEE A HALF INCH OR
LESS ALONG THE IL/WI STATE LINE. MODEL SOUNDINGS SUPPORT THIS AS
THEY SHOW OMEGA REMAINING LOWER THAN THE SATURATED DGZ LAYER. THEN
AS OMEGA LIFTS INTO THE SATURATED LAYER...THE OMEGA WEAKENS GREATLY
AND THE SATURATION ALSO WEAKENS.
WINDS TURN SW AND WEAK WAA WILL LEAD TO HIGH TEMPS IN THE MID TO
UPPER 20S. FAR SOUTHERN AREAS IN THE CWA MAY EVEN MAKE OR BREAK
FREEZING AS THEY DO NOT HAVE ANY SNOW ON THE GROUND AND WILL SEE
SOME SUN. WAA CONTINUES THROUGH TONIGHT...BUT THE SNOWPACK WILL
WREAK HAVOC WITH LOW TEMPS. WINDS LIGHTEN DUE TO THE BAGGY PRESSURE
PATTERN AND CLOUDS THIN OVERNIGHT. THE GOING LOW TEMPS LOOKED VERY
REASONABLE...THEREFORE DID NOT MAKE ANY MAJOR CHANGES. HAVE TEENS
OVER NORTH CENTRAL IL AND THEN LOW 20S IN THE SOUTHEAST CORNER OF
THE CWA.
FRIDAY AND SATURDAY...
UPPER LEVEL FLOW TURNS ZONAL THROUGH SATURDAY AND WAA REALLY KICKS
INTO HIGH GEAR FRIDAY AND SATURDAY. A LOW PASSES WELL TO OUR
NORTH...BUT WITH THE HIGH OVER THE GULF COAST...THE PRESSURE
GRADIENT TIGHTENS AND WINDS PICK UP. SW WINDS AROUND 10 KT WITH
GUSTS 15 TO 20 KT WILL HELP USHER IN THE WARMER AIR. GUIDANCE HAS
925MB TEMPS RISING TO +4C BY FRIDAY EVENING AND THEN TO +6 TO +8 BY
SATURDAY EVENING. AS SUCH RAISED TEMPS FRIDAY...FRIDAY NIGHT...AND
SATURDAY. CONFIDENCE IS MEDIUM-HIGH IN THE GOING FORECAST TEMPS FOR
THAT PERIOD.
FOR NOW CONTINUED THE TREND THAT THE END OF THIS WEEK LOOKS ABOVE
NORMAL IN THE TEMP DEPARTMENT. HOW WARM...NOT SURE. FOR AREAS WITH
LITTLE SNOW...ROUGHLY AREAS ALONG AND SOUTH OF I-88...THE WARM UP
COULD BE WARMER THAN CURRENTLY FORECAST. FOR NOW THINKING ABOVE
FREEZING ON FRIDAY AND 40S ON SATURDAY SEEM REASONABLE. FOR AREAS
NORTH OF I-88 THAT HAVE A DECENT SNOW PACK...THINGS COULD BE MORE
DICEY. RFD FOR INSTANCE HAS 7 INCHES OF SNOW ON THE GROUND...AND
THE WAA ADVECTION AND NEAR FREEZING TEMPS ON FRIDAY MAY NOT MAKE A
SIGNIFICANT DENT IN THE SNOW. AS SUCH WENT NEAR GUIDANCE FOR
THESE NORTHERN AREAS WITH TEMPS JUST ABOVE FREEZING FRIDAY...AND
AROUND 40 SATURDAY. COULD CERTAINLY SEE A TIGHT TEMP GRADIENT
WITHIN THE CWA AS THE SNOW FREE AREAS WARM QUICKLY...WHILE THE AREAS
WITH SNOW PACK STRUGGLE TO CLIMB.
EXTENDED...SUNDAY THROUGH TUESDAY...
THE SURFACE LOW SINKS SOUTH...MOVING OVER THE CWA SATURDAY NIGHT
INTO SUNDAY. AN UPPER LEVEL STREAMER ASSOCIATED WITH THE LOW
WEAKENS AS THE STRONGER UPPER LEVEL TROUGH CATCHES UP WITH THE LOW.
PRECIP IS EXPECTED ALONG AND BEHIND THE COLD FRONT. GUIDANCE
DIFFERS A BIT ON THE TIMING OF THE LOW AND AS TO HOW MUCH FORCING
WILL ACCOMPANY IT. THE GFS IS MORE VIGOROUS THAN THE ECMWF WITH
PRECIP...WHILE THE ECMWF IS A BIT FASTER. AS SUCH LEFT POPS IN THE
CHANCE RANGE UNTIL THE FORCING AND TIMING ASPECTS BECOME A BIT
CLEARER. OVERALL NOT EXPECTING A LOT OF PRECIP/SNOW.
THE BIGGER STORY WILL BE TEMPS. TEMPS WILL FALL SUNDAY AS COLD AIR
CONTINUES TO FUNNEL IN BEHIND THE TROUGH AXIS. 925MB TEMPS FALL TO
-4 TO -14C ALOFT BY SUNDAY EVENING WITH COLDER AIR EXPECTED
OVERNIGHT. HIGH PRESSURE ALSO APPROACHES FROM THE WEST SO CLEARING
SKIES AND NORTHWEST WINDS AROUND 10 KT WILL LEAD TO A VERY COLD
NIGHT. LOW TEMPS WILL RANGE FROM BELOW ZERO OVER NORTH CENTRAL IL TO
SINGLE DIGITS OVER NW INDIANA. MIN WIND CHILLS BELOW -20 ARE STILL
EXPECTED ACROSS NORTH CENTRAL IL SUNDAY NIGHT AND MONDAY NIGHT.
COLD CONTINUES THROUGH NEW YEARS EVE WITH A SLIGHT RELIEF EXPECTED
ON JAN 1ST. GUIDANCE CONTINUES TO HINT AT A PRECIP SYSTEM
TUESDAY...BUT GUIDANCE IS LESS CLEAR ON FORCING AND TIMING TODAY
COMPARED TO YESTERDAY. THEREFORE LEFT SLIGHT CHANCE TO CHANCE POPS
IN THROUGH MID WEEK.
JEE
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 20Z...
* LIGHT SNOW/FLURRIES LATE THIS AFTERNOON AND EARLY EVENING.
* CIG TRENDS...AND POTENTIAL FOR MVFR TO RETURN THIS EVENING AND
OVERNIGHT.
BMD
//DISCUSSION...UPDATED 18Z...
BAND OF SNOW IS EXITING EAST OF THIS CHICAGO TERMINALS THIS
AFTERNOON BUT A PAIR OF ADDITIONAL UPPER LEVEL DISTURBANCES TO THE
NORTHWEST WILL BRING ADDITIONAL CHANCES FOR SNOW THROUGH PORTIONS
OF THE AFTERNOON AND EVENING. THE FIRST WAVE IS CURRENTLY
DROPPING SOUTHEAST ACROSS IOWA WITH RADAR RETURNS ACROSS MUCH OF
THE EASTERN HALF OF IOWA AND NORTHWEST ILLINOIS. PER SURFACE OBS
HOWEVER...MOST OF THIS IS NOT REACHING THE GROUND...AND APPEARS
THE MAIN FORCING WILL DROP SOUTH OF THE TERMINALS EARLY THIS
AFTERNOON. THE NEXT WAVE IS OVER THE EASTERN DAKOTAS EARLY THIS
AFTERNOON AND WILL TAKE AIM AT THE IL/WI STATE LINE LATE THIS
AFTERNOON AND THIS EVENING. MOST MODELS INDICATE THAT THE
ACCUMULATING SNOWFALL WILL FALL NORTH OF THE TERMINALS...HOWEVER
SOME LIFT IS NOTED AS FAR SOUTH AS THE TERMINALS. ITS NOT CO-
LOCATED WELL WITH THE MOISTURE OR THE SNOW GROWTH ZONE...SO DO NOT
ANTICIPATE EFFICIENT SNOW PRODUCTION WITH THIS WAVE.
INSTEAD...EXPECT A PERIOD OF FLURRIES WITH GENERALLY VFR
CONDITIONS...THOUGH CANNOT RULE OUT PERHAPS A PERIODIC BRIEF DROPS
TO MVFR VSBY. WILL MONITOR UPSTREAM TRENDS THIS AFTERNOON TO
DETERMINE IF THE THREAT IS ENOUGH TO INCLUDE IN TAF.
THERE IS A WEAK SURFACE REFLECTION OF THE SECOND WAVE THIS EVENING.
SSW TO SW WINDS AHEAD OF THE SURFACE TROUGH WILL VEER TO THE WSW OR
WEST FOR A PERIOD THIS EVENING. BEHIND THIS SLIGHT WIND
SHIFT...FORECAST SOUNDINGS SHOW SATURATION OF THE LOWER LEVELS
INDICATING THE DEVELOPMENT OF MVFR OR IN SOME CASES IFR CIGS. MET
GUIDANCE INDICATES A SIMILAR DROP IN CIGS OVERNIGHT...WHILE MAV/LAV
GUIDANCE DOES NOT. WILL INTRODUCE MVFR CIGS INTO THE FORECAST...BUT
AM CONCERNED THAT LOWER CIGS ARE POSSIBLE. RAP LOW LEVEL MOISTURE
FIELDS INDICATE THESE CIGS WILL DEVELOP NEAR THE MISSISSIPPI RIVER
MID TO LATE THIS AFTERNOON...SO WILL GAIN MORE CONFIDENCE IN CIG
TRENDS BY THEN.
BMD
//ORD AND MDW CONFIDENCE...UPDATED 20Z...
* MEDIUM CONFIDENCE IN PRECIP/VSBY TRENDS.
* MEDIUM CONFIDENCE IN CIG TRENDS THROUGH THE AFTERNOON...THEN LOW
CONFIDENCE THIS EVENING/OVERNIGHT.
BMD
//OUTLOOK FOR ORD/MDW FOR 00Z SATURDAY-12Z THURSDAY...UPDATED 12Z...
FRIDAY NIGHT...VFR WIND.
SATURDAY...VFR WIND.
SUNDAY THROUGH TUESDAY NIGHT...PERIODS OF -SN WITH OCNL MVFR
CIGS/VSBY. A PERIOD OF IFR CIGS/VIS POSSIBLE.
WEDNESDAY...VFR WX NIL.
ED F
&&
.MARINE...
232 PM...A WEAK RIDGE CURRENTLY OVER THE WESTERN LAKES REGION
WILL DRIFT SOUTHEAST TONIGHT AND BE ABSORBED BY A MUCH LARGER AND
STRONGER HIGH OVER THE OHIO VALLEY. A FAST MOVING LOW WILL MOVE
ACROSS CENTRAL ONTARIO AND THE NORTHERN LAKES FRIDAY. THE GRADIENT
WILL TIGHTEN BETWEEN THIS APPROACHING LOW AND THE STRONG HIGH TO
THE SOUTH WITH GALES POSSIBLE ESPECIALLY ACROSS THE NORTHERN HALF
OF LAKE MICHIGAN. OVERALL DURATION PERHAPS 6 TO 9 HOURS AND HAVE
HOISTED A GALE WATCH FOR FRIDAY AFTERNOON/FRIDAY EVENING. AS THE
LOW LIFTS NORTHEAST INTO QUEBEC FRIDAY NIGHT...THE GRADIENT WILL
WEAKEN AND WHILE ITS POSSIBLE THERE COULD BE SOME GALE GUSTS ON
THE SOUTH HALF OF THE LAKE...CONFIDENCE DECREASES FURTHER SOUTH
AND HAVE HELD WINDS AT 30 KTS. A TRAILING COLD FRONT FROM THIS LOW
WILL SAG SOUTH ACROSS NORTHERN LAKE MICHIGAN SATURDAY EVENING WITH
NEW LOW PRESSURE FORMING OF THE PLAINS SATURDAY AND THEN MOVING
EAST/NORTHEAST ALONG THIS FRONT SATURDAY NIGHT INTO SUNDAY
MORNING. THIS WILL LIKELY SLOW THE FRONT/S PROGRESS SOUTH DOWN
LAKE MICHIGAN WITH SOUTHWESTERLY FLOW EXPECTED AHEAD OF THE FRONT
SATURDAY NIGHT. THE GRADIENT WILL TIGHTEN SHARPLY BEHIND THE FRONT
AND COMBINED WITH STRONG COLD AIR SPREADING ACROSS THE REGION...
NORTHERLY WINDS SHOULD EASILY INCREASE TO 30 KTS AND ITS POSSIBLE
FOR A PERIOD OF LOW END GALES. NORTHERLY WINDS WILL SLOWLY TURN
NORTHWEST SUNDAY INTO MONDAY AND GRADUALLY DIMINISH. CMS
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...GALE WATCH...LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-LMZ565-LMZ567-
LMZ868...NOON FRIDAY TO MIDNIGHT SATURDAY.
&&
$$
VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)
FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/US.NATIONALWEATHERSERVICE.CHICAGO.GOV
WWW.TWITTER.COM/NWSCHICAGO
WWW.YOUTUBE.COM/NWSCHICAGO
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
147 PM CST THU DEC 26 2013
.DISCUSSION...
930 AM CST
HAVE MADE SOME MINOR ADJUSTMENTS TO THE WX/POP/QPS FOR THE REST OF
THIS MORNING AND INTO THIS AFTERNOON. A SERIES OF SHORTWAVES
RIPPLING THROUGH THE FAST NORTHWEST FLOW ALOFT ARE ALREADY
GENERATING SOME LIGHT SNOW ACROSS NRN IL. THE LATEST GUIDANCE AND
UPSTREAM SATELLITE IMAGERY SUGGEST THAT A COUPLE MORE ORGANIZED
SHORTWAVES WILL TRAVERSE THE NRN PORTIONS OF THE CWA THIS
AFTERNOON. SO HAVE BUMPED UP POPS FOR THE REMAINDER OF TODAY.
WHILE THIS LOOKS TO BE MORE OF A HIGHER POP...LOWER QPF
SITUATION...WILL STILL CARRY MEASURABLE PCPN FOR THIS AFTERNOON...
BUT GIVEN THE EXPECTATIONS OF RELATIVELY HIGH SNOW TO LIQUID RATIO
LIKELY...ANY SNOWFALL WOULD MOST LIKELY BE OBSERVED AS A DUSTING
AND DIFFICULT TO ACTUALLY MEASURE.
KREIN
.PREVIOUS DISCUSSION...
335 AM CST
SYNOPSIS...LIGHT SNOW IS POSSIBLE THIS AFTERNOON ALONG THE IL/WI
STATE LINE...THEN THE WARM UP IS ON THROUGH SATURDAY. TEMPS CRASH
BEHIND THE LOW SUNDAY WITH VERY COLD AIR RETURNING TO THE REGION.
SNOW IS POSSIBLE ON SUNDAY BUT THE BETTER CHANCE LOOKS TO BE MONDAY
NIGHT INTO TUESDAY.
TODAY AND TONIGHT...
THE UPPER LEVEL TROUGH AXIS HAS PUSHED EAST OF THE AREA ALONG WITH
THE SNOW WE SAW LAST NIGHT. AT THE SURFACE...WEAK LOW PRESSURE IS
OVER SOUTHWESTERN ONTARIO. HIGH PRESSURE IS CENTERED OVER TEXARKANA
BUT ITS RIDGE EXTENDS NORTH THROUGH THE MISSISSIPPI RIVER VALLEY.
THE RIDGE WILL MOVE OVERHEAD THIS MORNING WHILE THE MAIN HIGH
REMAINS TO OUR SOUTH.
A WEAK SHORTWAVE PASSES THROUGH WI THIS AFTN KICKING OFF SNOW
SHOWERS. THE MAIN VORT WILL BE OVER CENTRAL WI SO THINKING THE
MAJORITY OF PRECIP WILL BE OVER WI...BUT COULD SEE A HALF INCH OR
LESS ALONG THE IL/WI STATE LINE. MODEL SOUNDINGS SUPPORT THIS AS
THEY SHOW OMEGA REMAINING LOWER THAN THE SATURATED DGZ LAYER. THEN
AS OMEGA LIFTS INTO THE SATURATED LAYER...THE OMEGA WEAKENS GREATLY
AND THE SATURATION ALSO WEAKENS.
WINDS TURN SW AND WEAK WAA WILL LEAD TO HIGH TEMPS IN THE MID TO
UPPER 20S. FAR SOUTHERN AREAS IN THE CWA MAY EVEN MAKE OR BREAK
FREEZING AS THEY DO NOT HAVE ANY SNOW ON THE GROUND AND WILL SEE
SOME SUN. WAA CONTINUES THROUGH TONIGHT...BUT THE SNOWPACK WILL
WREAK HAVOC WITH LOW TEMPS. WINDS LIGHTEN DUE TO THE BAGGY PRESSURE
PATTERN AND CLOUDS THIN OVERNIGHT. THE GOING LOW TEMPS LOOKED VERY
REASONABLE...THEREFORE DID NOT MAKE ANY MAJOR CHANGES. HAVE TEENS
OVER NORTH CENTRAL IL AND THEN LOW 20S IN THE SOUTHEAST CORNER OF
THE CWA.
FRIDAY AND SATURDAY...
UPPER LEVEL FLOW TURNS ZONAL THROUGH SATURDAY AND WAA REALLY KICKS
INTO HIGH GEAR FRIDAY AND SATURDAY. A LOW PASSES WELL TO OUR
NORTH...BUT WITH THE HIGH OVER THE GULF COAST...THE PRESSURE
GRADIENT TIGHTENS AND WINDS PICK UP. SW WINDS AROUND 10 KT WITH
GUSTS 15 TO 20 KT WILL HELP USHER IN THE WARMER AIR. GUIDANCE HAS
925MB TEMPS RISING TO +4C BY FRIDAY EVENING AND THEN TO +6 TO +8 BY
SATURDAY EVENING. AS SUCH RAISED TEMPS FRIDAY...FRIDAY NIGHT...AND
SATURDAY. CONFIDENCE IS MEDIUM-HIGH IN THE GOING FORECAST TEMPS FOR
THAT PERIOD.
FOR NOW CONTINUED THE TREND THAT THE END OF THIS WEEK LOOKS ABOVE
NORMAL IN THE TEMP DEPARTMENT. HOW WARM...NOT SURE. FOR AREAS WITH
LITTLE SNOW...ROUGHLY AREAS ALONG AND SOUTH OF I-88...THE WARM UP
COULD BE WARMER THAN CURRENTLY FORECAST. FOR NOW THINKING ABOVE
FREEZING ON FRIDAY AND 40S ON SATURDAY SEEM REASONABLE. FOR AREAS
NORTH OF I-88 THAT HAVE A DECENT SNOW PACK...THINGS COULD BE MORE
DICEY. RFD FOR INSTANCE HAS 7 INCHES OF SNOW ON THE GROUND...AND
THE WAA ADVECTION AND NEAR FREEZING TEMPS ON FRIDAY MAY NOT MAKE A
SIGNIFICANT DENT IN THE SNOW. AS SUCH WENT NEAR GUIDANCE FOR
THESE NORTHERN AREAS WITH TEMPS JUST ABOVE FREEZING FRIDAY...AND
AROUND 40 SATURDAY. COULD CERTAINLY SEE A TIGHT TEMP GRADIENT
WITHIN THE CWA AS THE SNOW FREE AREAS WARM QUICKLY...WHILE THE AREAS
WITH SNOW PACK STRUGGLE TO CLIMB.
EXTENDED...SUNDAY THROUGH TUESDAY...
THE SURFACE LOW SINKS SOUTH...MOVING OVER THE CWA SATURDAY NIGHT
INTO SUNDAY. AN UPPER LEVEL STREAMER ASSOCIATED WITH THE LOW
WEAKENS AS THE STRONGER UPPER LEVEL TROUGH CATCHES UP WITH THE LOW.
PRECIP IS EXPECTED ALONG AND BEHIND THE COLD FRONT. GUIDANCE
DIFFERS A BIT ON THE TIMING OF THE LOW AND AS TO HOW MUCH FORCING
WILL ACCOMPANY IT. THE GFS IS MORE VIGOROUS THAN THE ECMWF WITH
PRECIP...WHILE THE ECMWF IS A BIT FASTER. AS SUCH LEFT POPS IN THE
CHANCE RANGE UNTIL THE FORCING AND TIMING ASPECTS BECOME A BIT
CLEARER. OVERALL NOT EXPECTING A LOT OF PRECIP/SNOW.
THE BIGGER STORY WILL BE TEMPS. TEMPS WILL FALL SUNDAY AS COLD AIR
CONTINUES TO FUNNEL IN BEHIND THE TROUGH AXIS. 925MB TEMPS FALL TO
-4 TO -14C ALOFT BY SUNDAY EVENING WITH COLDER AIR EXPECTED
OVERNIGHT. HIGH PRESSURE ALSO APPROACHES FROM THE WEST SO CLEARING
SKIES AND NORTHWEST WINDS AROUND 10 KT WILL LEAD TO A VERY COLD
NIGHT. LOW TEMPS WILL RANGE FROM BELOW ZERO OVER NORTH CENTRAL IL TO
SINGLE DIGITS OVER NW INDIANA. MIN WIND CHILLS BELOW -20 ARE STILL
EXPECTED ACROSS NORTH CENTRAL IL SUNDAY NIGHT AND MONDAY NIGHT.
COLD CONTINUES THROUGH NEW YEARS EVE WITH A SLIGHT RELIEF EXPECTED
ON JAN 1ST. GUIDANCE CONTINUES TO HINT AT A PRECIP SYSTEM
TUESDAY...BUT GUIDANCE IS LESS CLEAR ON FORCING AND TIMING TODAY
COMPARED TO YESTERDAY. THEREFORE LEFT SLIGHT CHANCE TO CHANCE POPS
IN THROUGH MID WEEK.
JEE
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 20Z...
* LIGHT SNOW/FLURRIES LATE THIS AFTERNOON AND EARLY EVENING.
* CIG TRENDS...AND POTENTIAL FOR MVFR TO RETURN THIS EVENING AND
OVERNIGHT.
BMD
//DISCUSSION...UPDATED 18Z...
BAND OF SNOW IS EXITING EAST OF THIS CHICAGO TERMINALS THIS
AFTERNOON BUT A PAIR OF ADDITIONAL UPPER LEVEL DISTURBANCES TO THE
NORTHWEST WILL BRING ADDITIONAL CHANCES FOR SNOW THROUGH PORTIONS
OF THE AFTERNOON AND EVENING. THE FIRST WAVE IS CURRENTLY
DROPPING SOUTHEAST ACROSS IOWA WITH RADAR RETURNS ACROSS MUCH OF
THE EASTERN HALF OF IOWA AND NORTHWEST ILLINOIS. PER SURFACE OBS
HOWEVER...MOST OF THIS IS NOT REACHING THE GROUND...AND APPEARS
THE MAIN FORCING WILL DROP SOUTH OF THE TERMINALS EARLY THIS
AFTERNOON. THE NEXT WAVE IS OVER THE EASTERN DAKOTAS EARLY THIS
AFTERNOON AND WILL TAKE AIM AT THE IL/WI STATE LINE LATE THIS
AFTERNOON AND THIS EVENING. MOST MODELS INDICATE THAT THE
ACCUMULATING SNOWFALL WILL FALL NORTH OF THE TERMINALS...HOWEVER
SOME LIFT IS NOTED AS FAR SOUTH AS THE TERMINALS. ITS NOT CO-
LOCATED WELL WITH THE MOISTURE OR THE SNOW GROWTH ZONE...SO DO NOT
ANTICIPATE EFFICIENT SNOW PRODUCTION WITH THIS WAVE.
INSTEAD...EXPECT A PERIOD OF FLURRIES WITH GENERALLY VFR
CONDITIONS...THOUGH CANNOT RULE OUT PERHAPS A PERIODIC BRIEF DROPS
TO MVFR VSBY. WILL MONITOR UPSTREAM TRENDS THIS AFTERNOON TO
DETERMINE IF THE THREAT IS ENOUGH TO INCLUDE IN TAF.
THERE IS A WEAK SURFACE REFLECTION OF THE SECOND WAVE THIS EVENING.
SSW TO SW WINDS AHEAD OF THE SURFACE TROUGH WILL VEER TO THE WSW OR
WEST FOR A PERIOD THIS EVENING. BEHIND THIS SLIGHT WIND
SHIFT...FORECAST SOUNDINGS SHOW SATURATION OF THE LOWER LEVELS
INDICATING THE DEVELOPMENT OF MVFR OR IN SOME CASES IFR CIGS. MET
GUIDANCE INDICATES A SIMILAR DROP IN CIGS OVERNIGHT...WHILE MAV/LAV
GUIDANCE DOES NOT. WILL INTRODUCE MVFR CIGS INTO THE FORECAST...BUT
AM CONCERNED THAT LOWER CIGS ARE POSSIBLE. RAP LOW LEVEL MOISTURE
FIELDS INDICATE THESE CIGS WILL DEVELOP NEAR THE MISSISSIPPI RIVER
MID TO LATE THIS AFTERNOON...SO WILL GAIN MORE CONFIDENCE IN CIG
TRENDS BY THEN.
BMD
//ORD AND MDW CONFIDENCE...UPDATED 20Z...
* MEDIUM CONFIDENCE IN PRECIP/VSBY TRENDS.
* MEDIUM CONFIDENCE IN CIG TRENDS THROUGH THE AFTERNOON...THEN LOW
CONFIDENCE THIS EVENING/OVERNIGHT.
BMD
//OUTLOOK FOR ORD/MDW FOR 00Z SATURDAY-12Z THURSDAY...UPDATED 12Z...
FRIDAY NIGHT...VFR WIND.
SATURDAY...VFR WIND.
SUNDAY THROUGH TUESDAY NIGHT...PERIODS OF -SN WITH OCNL MVFR
CIGS/VSBY. A PERIOD OF IFR CIGS/VIS POSSIBLE.
WEDNESDAY...VFR WX NIL.
ED F
&&
.MARINE...
327 AM CST
AN ACTIVE PERIOD ON LAKE MICHIGAN WEATHER WISE ON TAP FOR THE
NEXT 5 DAYS AS THE AREA REMAINS UNDER THE INFLUENCE OF FAST
NORTHWEST FLOW ALOFT THAT BECOMES ZONAL BRIEFLY FRIDAY-SATURDAY.
THIS WILL SET THE STAGE FOR A COUPLE OF SEPARATE SYSTEMS TO
POSSIBLY PRODUCE MULTIPLE PERIODS OF GALE FORCE WINDS FRIDAY
THROUGH SUNDAY. LOW PRESSURE DEPARTING THE AREA TODAY WILL BE
REPLACED WITH A RIDGE AXIS SLIDING EAST ACROSS THE LAKE THIS
EVENING. LOW PRESSURE WILL THEN MOVE OUT OF SASKATCHEWAN TO
NORTHERN LAKE SUPERIOR BY FRIDAY EVENING. THE STRONG PRESSURE
CONTRAST BETWEEN THIS LOW AND HIGH PRESSURE TO THE SOUTHEAST WILL
LIKELY RESULT IN GALE FORCE WINDS FOR A PERIOD LATE FRIDAY/FRIDAY
NIGHT.
UNCERTAINTY SURROUNDING A SECOND AREA OF LOW PRESSURE POTENTIALLY
STRONGER MOVING OUT OF THE PLAINS AND INTO THE WESTERN GREAT LAKES
BY EARLY SUNDAY WILL SET THE STAGE FOR ADDITIONAL PERIODS OF GALES
POSSIBLY SATURDAY AND SUNDAY DEPENDING ON HOW EXACTLY THIS LOW
EVOLVES. AT THE SAME TIME WINDS CLOSER TO THE TRACK OF THE LOW
ITSELF WILL BE LIGHTER. MOST ANY FORECAST BUT THIS ONE IN
PARTICULAR WILL BE BEST MONITORED VIA THE GRAPHICAL FORECASTS
AVAILABLE ON THE WEB AT WWW.WEATHER.GOV/GREATLAKES IN ORDER TO SEE
THE RICHNESS OF THE DETAIL EXPECTED GIVEN THIS COMPLEX SITUATION.
ED F
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...GALE WATCH...LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-LMZ565-LMZ567-
LMZ868...NOON FRIDAY TO MIDNIGHT SATURDAY.
&&
$$
VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)
FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/US.NATIONALWEATHERSERVICE.CHICAGO.GOV
WWW.TWITTER.COM/NWSCHICAGO
WWW.YOUTUBE.COM/NWSCHICAGO
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
1202 PM CST THU DEC 26 2013
.DISCUSSION...
930 AM CST
HAVE MADE SOME MINOR ADJUSTMENTS TO THE WX/POP/QPS FOR THE REST OF
THIS MORNING AND INTO THIS AFTERNOON. A SERIES OF SHORTWAVES
RIPPLING THROUGH THE FAST NORTHWEST FLOW ALOFT ARE ALREADY
GENERATING SOME LIGHT SNOW ACROSS NRN IL. THE LATEST GUIDANCE AND
UPSTREAM SATELLITE IMAGERY SUGGEST THAT A COUPLE MORE ORGANIZED
SHORTWAVES WILL TRAVERSE THE NRN PORTIONS OF THE CWA THIS
AFTERNOON. SO HAVE BUMPED UP POPS FOR THE REMAINDER OF TODAY.
WHILE THIS LOOKS TO BE MORE OF A HIGHER POP...LOWER QPF
SITUATION...WILL STILL CARRY MEASURABLE PCPN FOR THIS AFTERNOON...
BUT GIVEN THE EXPECTATIONS OF RELATIVELY HIGH SNOW TO LIQUID RATIO
LIKELY...ANY SNOWFALL WOULD MOST LIKELY BE OBSERVED AS A DUSTING
AND DIFFICULT TO ACTUALLY MEASURE.
KREIN
.PREVIOUS DISCUSSION...
335 AM CST
SYNOPSIS...LIGHT SNOW IS POSSIBLE THIS AFTERNOON ALONG THE IL/WI
STATE LINE...THEN THE WARM UP IS ON THROUGH SATURDAY. TEMPS CRASH
BEHIND THE LOW SUNDAY WITH VERY COLD AIR RETURNING TO THE REGION.
SNOW IS POSSIBLE ON SUNDAY BUT THE BETTER CHANCE LOOKS TO BE MONDAY
NIGHT INTO TUESDAY.
TODAY AND TONIGHT...
THE UPPER LEVEL TROUGH AXIS HAS PUSHED EAST OF THE AREA ALONG WITH
THE SNOW WE SAW LAST NIGHT. AT THE SURFACE...WEAK LOW PRESSURE IS
OVER SOUTHWESTERN ONTARIO. HIGH PRESSURE IS CENTERED OVER TEXARKANA
BUT ITS RIDGE EXTENDS NORTH THROUGH THE MISSISSIPPI RIVER VALLEY.
THE RIDGE WILL MOVE OVERHEAD THIS MORNING WHILE THE MAIN HIGH
REMAINS TO OUR SOUTH.
A WEAK SHORTWAVE PASSES THROUGH WI THIS AFTN KICKING OFF SNOW
SHOWERS. THE MAIN VORT WILL BE OVER CENTRAL WI SO THINKING THE
MAJORITY OF PRECIP WILL BE OVER WI...BUT COULD SEE A HALF INCH OR
LESS ALONG THE IL/WI STATE LINE. MODEL SOUNDINGS SUPPORT THIS AS
THEY SHOW OMEGA REMAINING LOWER THAN THE SATURATED DGZ LAYER. THEN
AS OMEGA LIFTS INTO THE SATURATED LAYER...THE OMEGA WEAKENS GREATLY
AND THE SATURATION ALSO WEAKENS.
WINDS TURN SW AND WEAK WAA WILL LEAD TO HIGH TEMPS IN THE MID TO
UPPER 20S. FAR SOUTHERN AREAS IN THE CWA MAY EVEN MAKE OR BREAK
FREEZING AS THEY DO NOT HAVE ANY SNOW ON THE GROUND AND WILL SEE
SOME SUN. WAA CONTINUES THROUGH TONIGHT...BUT THE SNOWPACK WILL
WREAK HAVOC WITH LOW TEMPS. WINDS LIGHTEN DUE TO THE BAGGY PRESSURE
PATTERN AND CLOUDS THIN OVERNIGHT. THE GOING LOW TEMPS LOOKED VERY
REASONABLE...THEREFORE DID NOT MAKE ANY MAJOR CHANGES. HAVE TEENS
OVER NORTH CENTRAL IL AND THEN LOW 20S IN THE SOUTHEAST CORNER OF
THE CWA.
FRIDAY AND SATURDAY...
UPPER LEVEL FLOW TURNS ZONAL THROUGH SATURDAY AND WAA REALLY KICKS
INTO HIGH GEAR FRIDAY AND SATURDAY. A LOW PASSES WELL TO OUR
NORTH...BUT WITH THE HIGH OVER THE GULF COAST...THE PRESSURE
GRADIENT TIGHTENS AND WINDS PICK UP. SW WINDS AROUND 10 KT WITH
GUSTS 15 TO 20 KT WILL HELP USHER IN THE WARMER AIR. GUIDANCE HAS
925MB TEMPS RISING TO +4C BY FRIDAY EVENING AND THEN TO +6 TO +8 BY
SATURDAY EVENING. AS SUCH RAISED TEMPS FRIDAY...FRIDAY NIGHT...AND
SATURDAY. CONFIDENCE IS MEDIUM-HIGH IN THE GOING FORECAST TEMPS FOR
THAT PERIOD.
FOR NOW CONTINUED THE TREND THAT THE END OF THIS WEEK LOOKS ABOVE
NORMAL IN THE TEMP DEPARTMENT. HOW WARM...NOT SURE. FOR AREAS WITH
LITTLE SNOW...ROUGHLY AREAS ALONG AND SOUTH OF I-88...THE WARM UP
COULD BE WARMER THAN CURRENTLY FORECAST. FOR NOW THINKING ABOVE
FREEZING ON FRIDAY AND 40S ON SATURDAY SEEM REASONABLE. FOR AREAS
NORTH OF I-88 THAT HAVE A DECENT SNOW PACK...THINGS COULD BE MORE
DICEY. RFD FOR INSTANCE HAS 7 INCHES OF SNOW ON THE GROUND...AND
THE WAA ADVECTION AND NEAR FREEZING TEMPS ON FRIDAY MAY NOT MAKE A
SIGNIFICANT DENT IN THE SNOW. AS SUCH WENT NEAR GUIDANCE FOR
THESE NORTHERN AREAS WITH TEMPS JUST ABOVE FREEZING FRIDAY...AND
AROUND 40 SATURDAY. COULD CERTAINLY SEE A TIGHT TEMP GRADIENT
WITHIN THE CWA AS THE SNOW FREE AREAS WARM QUICKLY...WHILE THE AREAS
WITH SNOW PACK STRUGGLE TO CLIMB.
EXTENDED...SUNDAY THROUGH TUESDAY...
THE SURFACE LOW SINKS SOUTH...MOVING OVER THE CWA SATURDAY NIGHT
INTO SUNDAY. AN UPPER LEVEL STREAMER ASSOCIATED WITH THE LOW
WEAKENS AS THE STRONGER UPPER LEVEL TROUGH CATCHES UP WITH THE LOW.
PRECIP IS EXPECTED ALONG AND BEHIND THE COLD FRONT. GUIDANCE
DIFFERS A BIT ON THE TIMING OF THE LOW AND AS TO HOW MUCH FORCING
WILL ACCOMPANY IT. THE GFS IS MORE VIGOROUS THAN THE ECMWF WITH
PRECIP...WHILE THE ECMWF IS A BIT FASTER. AS SUCH LEFT POPS IN THE
CHANCE RANGE UNTIL THE FORCING AND TIMING ASPECTS BECOME A BIT
CLEARER. OVERALL NOT EXPECTING A LOT OF PRECIP/SNOW.
THE BIGGER STORY WILL BE TEMPS. TEMPS WILL FALL SUNDAY AS COLD AIR
CONTINUES TO FUNNEL IN BEHIND THE TROUGH AXIS. 925MB TEMPS FALL TO
-4 TO -14C ALOFT BY SUNDAY EVENING WITH COLDER AIR EXPECTED
OVERNIGHT. HIGH PRESSURE ALSO APPROACHES FROM THE WEST SO CLEARING
SKIES AND NORTHWEST WINDS AROUND 10 KT WILL LEAD TO A VERY COLD
NIGHT. LOW TEMPS WILL RANGE FROM BELOW ZERO OVER NORTH CENTRAL IL TO
SINGLE DIGITS OVER NW INDIANA. MIN WIND CHILLS BELOW -20 ARE STILL
EXPECTED ACROSS NORTH CENTRAL IL SUNDAY NIGHT AND MONDAY NIGHT.
COLD CONTINUES THROUGH NEW YEARS EVE WITH A SLIGHT RELIEF EXPECTED
ON JAN 1ST. GUIDANCE CONTINUES TO HINT AT A PRECIP SYSTEM
TUESDAY...BUT GUIDANCE IS LESS CLEAR ON FORCING AND TIMING TODAY
COMPARED TO YESTERDAY. THEREFORE LEFT SLIGHT CHANCE TO CHANCE POPS
IN THROUGH MID WEEK.
JEE
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 18Z...
* LIGHT SNOW/FLURRIES LATE THIS AFTERNOON AND EARLY EVENING.
* CIG TRENDS...AND POTENTIAL FOR MVFR TO RETURN THIS EVENING AND
OVERNIGHT.
BMD
//DISCUSSION...UPDATED 18Z...
BAND OF SNOW IS EXITING EAST OF THIS CHICAGO TERMINALS THIS
AFTERNOON BUT A PAIR OF ADDITIONAL UPPER LEVEL DISTURBANCES TO THE
NORTHWEST WILL BRING ADDITIONAL CHANCES FOR SNOW THROUGH PORTIONS
OF THE AFTERNOON AND EVENING. THE FIRST WAVE IS CURRENTLY
DROPPING SOUTHEAST ACROSS IOWA WITH RADAR RETURNS ACROSS MUCH OF
THE EASTERN HALF OF IOWA AND NORTHWEST ILLINOIS. PER SURFACE OBS
HOWEVER...MOST OF THIS IS NOT REACHING THE GROUND...AND APPEARS
THE MAIN FORCING WILL DROP SOUTH OF THE TERMINALS EARLY THIS
AFTERNOON. THE NEXT WAVE IS OVER THE EASTERN DAKOTAS EARLY THIS
AFTERNOON AND WILL TAKE AIM AT THE IL/WI STATE LINE LATE THIS
AFTERNOON AND THIS EVENING. MOST MODELS INDICATE THAT THE
ACCUMULATING SNOWFALL WILL FALL NORTH OF THE TERMINALS...HOWEVER
SOME LIFT IS NOTED AS FAR SOUTH AS THE TERMINALS. ITS NOT CO-
LOCATED WELL WITH THE MOISTURE OR THE SNOW GROWTH ZONE...SO DO NOT
ANTICIPATE EFFICIENT SNOW PRODUCTION WITH THIS WAVE.
INSTEAD...EXPECT A PERIOD OF FLURRIES WITH GENERALLY VFR
CONDITIONS...THOUGH CANNOT RULE OUT PERHAPS A PERIODIC BRIEF DROPS
TO MVFR VSBY. WILL MONITOR UPSTREAM TRENDS THIS AFTERNOON TO
DETERMINE IF THE THREAT IS ENOUGH TO INCLUDE IN TAF.
THERE IS A WEAK SURFACE REFLECTION OF THE SECOND WAVE THIS EVENING.
SSW TO SW WINDS AHEAD OF THE SURFACE TROUGH WILL VEER TO THE WSW OR
WEST FOR A PERIOD THIS EVENING. BEHIND THIS SLIGHT WIND
SHIFT...FORECAST SOUNDINGS SHOW SATURATION OF THE LOWER LEVELS
INDICATING THE DEVELOPMENT OF MVFR OR IN SOME CASES IFR CIGS. MET
GUIDANCE INDICATES A SIMILAR DROP IN CIGS OVERNIGHT...WHILE MAV/LAV
GUIDANCE DOES NOT. WILL INTRODUCE MVFR CIGS INTO THE FORECAST...BUT
AM CONCERNED THAT LOWER CIGS ARE POSSIBLE. RAP LOW LEVEL MOISTURE
FIELDS INDICATE THESE CIGS WILL DEVELOP NEAR THE MISSISSIPPI RIVER
MID TO LATE THIS AFTERNOON...SO WILL GAIN MORE CONFIDENCE IN CIG
TRENDS BY THEN.
BMD
//ORD AND MDW CONFIDENCE...UPDATED 18Z...
* MEDIUM CONFIDENCE IN PRECIP/VSBY TRENDS.
* MEDIUM CONFIDENCE IN CIG TRENDS THROUGH THE AFTERNOON...THEN LOW
CONFIDENCE THIS EVENING/OVERNIGHT.
BMD
//OUTLOOK FOR ORD/MDW FOR 00Z SATURDAY-12Z THURSDAY...UPDATED 12Z...
FRIDAY NIGHT...VFR WIND.
SATURDAY...VFR WIND.
SUNDAY THROUGH TUESDAY NIGHT...PERIODS OF -SN WITH OCNL MVFR
CIGS/VSBY. A PERIOD OF IFR CIGS/VIS POSSIBLE.
WEDNESDAY...VFR WX NIL.
ED F
&&
.MARINE...
327 AM CST
AN ACTIVE PERIOD ON LAKE MICHIGAN WEATHER WISE ON TAP FOR THE
NEXT 5 DAYS AS THE AREA REMAINS UNDER THE INFLUENCE OF FAST
NORTHWEST FLOW ALOFT THAT BECOMES ZONAL BRIEFLY FRIDAY-SATURDAY.
THIS WILL SET THE STAGE FOR A COUPLE OF SEPARATE SYSTEMS TO
POSSIBLY PRODUCE MULTIPLE PERIODS OF GALE FORCE WINDS FRIDAY
THROUGH SUNDAY. LOW PRESSURE DEPARTING THE AREA TODAY WILL BE
REPLACED WITH A RIDGE AXIS SLIDING EAST ACROSS THE LAKE THIS
EVENING. LOW PRESSURE WILL THEN MOVE OUT OF SASKATCHEWAN TO
NORTHERN LAKE SUPERIOR BY FRIDAY EVENING. THE STRONG PRESSURE
CONTRAST BETWEEN THIS LOW AND HIGH PRESSURE TO THE SOUTHEAST WILL
LIKELY RESULT IN GALE FORCE WINDS FOR A PERIOD LATE FRIDAY/FRIDAY
NIGHT.
UNCERTAINTY SURROUNDING A SECOND AREA OF LOW PRESSURE POTENTIALLY
STRONGER MOVING OUT OF THE PLAINS AND INTO THE WESTERN GREAT LAKES
BY EARLY SUNDAY WILL SET THE STAGE FOR ADDITIONAL PERIODS OF GALES
POSSIBLY SATURDAY AND SUNDAY DEPENDING ON HOW EXACTLY THIS LOW
EVOLVES. AT THE SAME TIME WINDS CLOSER TO THE TRACK OF THE LOW
ITSELF WILL BE LIGHTER. MOST ANY FORECAST BUT THIS ONE IN
PARTICULAR WILL BE BEST MONITORED VIA THE GRAPHICAL FORECASTS
AVAILABLE ON THE WEB AT WWW.WEATHER.GOV/GREATLAKES IN ORDER TO SEE
THE RICHNESS OF THE DETAIL EXPECTED GIVEN THIS COMPLEX SITUATION.
ED F
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...NONE.
&&
$$
VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)
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AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
1007 AM CST THU DEC 26 2013
.DISCUSSION...
930 AM CST
HAVE MADE SOME MINOR ADJUSTMENTS TO THE WX/POP/QPS FOR THE REST OF
THIS MORNING AND INTO THIS AFTERNOON. A SERIES OF SHORTWAVES
RIPPLING THROUGH THE FAST NORTHWEST FLOW ALOFT ARE ALREADY
GENERATING SOME LIGHT SNOW ACROSS NRN IL. THE LATEST GUIDANCE AND
UPSTREAM SATELLITE IMAGERY SUGGEST THAT A COUPLE MORE ORGANIZED
SHORTWAVES WILL TRAVERSE THE NRN PORTIONS OF THE CWA THIS
AFTERNOON. SO HAVE BUMPED UP POPS FOR THE REMAINDER OF TODAY.
WHILE THIS LOOKS TO BE MORE OF A HIGHER POP...LOWER QPF
SITUATION...WILL STILL CARRY MEASURABLE PCPN FOR THIS AFTERNOON...
BUT GIVEN THE EXPECTATIONS OF RELATIVELY HIGH SNOW TO LIQUID RATIO
LIKELY...ANY SNOWFALL WOULD MOST LIKELY BE OBSERVED AS A DUSTING
AND DIFFICULT TO ACTUALLY MEASURE.
KREIN
.PREVIOUS DISCUSSION...
335 AM CST
SYNOPSIS...LIGHT SNOW IS POSSIBLE THIS AFTERNOON ALONG THE IL/WI
STATE LINE...THEN THE WARM UP IS ON THROUGH SATURDAY. TEMPS CRASH
BEHIND THE LOW SUNDAY WITH VERY COLD AIR RETURNING TO THE REGION.
SNOW IS POSSIBLE ON SUNDAY BUT THE BETTER CHANCE LOOKS TO BE MONDAY
NIGHT INTO TUESDAY.
TODAY AND TONIGHT...
THE UPPER LEVEL TROUGH AXIS HAS PUSHED EAST OF THE AREA ALONG WITH
THE SNOW WE SAW LAST NIGHT. AT THE SURFACE...WEAK LOW PRESSURE IS
OVER SOUTHWESTERN ONTARIO. HIGH PRESSURE IS CENTERED OVER TEXARKANA
BUT ITS RIDGE EXTENDS NORTH THROUGH THE MISSISSIPPI RIVER VALLEY.
THE RIDGE WILL MOVE OVERHEAD THIS MORNING WHILE THE MAIN HIGH
REMAINS TO OUR SOUTH.
A WEAK SHORTWAVE PASSES THROUGH WI THIS AFTN KICKING OFF SNOW
SHOWERS. THE MAIN VORT WILL BE OVER CENTRAL WI SO THINKING THE
MAJORITY OF PRECIP WILL BE OVER WI...BUT COULD SEE A HALF INCH OR
LESS ALONG THE IL/WI STATE LINE. MODEL SOUNDINGS SUPPORT THIS AS
THEY SHOW OMEGA REMAINING LOWER THAN THE SATURATED DGZ LAYER. THEN
AS OMEGA LIFTS INTO THE SATURATED LAYER...THE OMEGA WEAKENS GREATLY
AND THE SATURATION ALSO WEAKENS.
WINDS TURN SW AND WEAK WAA WILL LEAD TO HIGH TEMPS IN THE MID TO
UPPER 20S. FAR SOUTHERN AREAS IN THE CWA MAY EVEN MAKE OR BREAK
FREEZING AS THEY DO NOT HAVE ANY SNOW ON THE GROUND AND WILL SEE
SOME SUN. WAA CONTINUES THROUGH TONIGHT...BUT THE SNOWPACK WILL
WREAK HAVOC WITH LOW TEMPS. WINDS LIGHTEN DUE TO THE BAGGY PRESSURE
PATTERN AND CLOUDS THIN OVERNIGHT. THE GOING LOW TEMPS LOOKED VERY
REASONABLE...THEREFORE DID NOT MAKE ANY MAJOR CHANGES. HAVE TEENS
OVER NORTH CENTRAL IL AND THEN LOW 20S IN THE SOUTHEAST CORNER OF
THE CWA.
FRIDAY AND SATURDAY...
UPPER LEVEL FLOW TURNS ZONAL THROUGH SATURDAY AND WAA REALLY KICKS
INTO HIGH GEAR FRIDAY AND SATURDAY. A LOW PASSES WELL TO OUR
NORTH...BUT WITH THE HIGH OVER THE GULF COAST...THE PRESSURE
GRADIENT TIGHTENS AND WINDS PICK UP. SW WINDS AROUND 10 KT WITH
GUSTS 15 TO 20 KT WILL HELP USHER IN THE WARMER AIR. GUIDANCE HAS
925MB TEMPS RISING TO +4C BY FRIDAY EVENING AND THEN TO +6 TO +8 BY
SATURDAY EVENING. AS SUCH RAISED TEMPS FRIDAY...FRIDAY NIGHT...AND
SATURDAY. CONFIDENCE IS MEDIUM-HIGH IN THE GOING FORECAST TEMPS FOR
THAT PERIOD.
FOR NOW CONTINUED THE TREND THAT THE END OF THIS WEEK LOOKS ABOVE
NORMAL IN THE TEMP DEPARTMENT. HOW WARM...NOT SURE. FOR AREAS WITH
LITTLE SNOW...ROUGHLY AREAS ALONG AND SOUTH OF I-88...THE WARM UP
COULD BE WARMER THAN CURRENTLY FORECAST. FOR NOW THINKING ABOVE
FREEZING ON FRIDAY AND 40S ON SATURDAY SEEM REASONABLE. FOR AREAS
NORTH OF I-88 THAT HAVE A DECENT SNOW PACK...THINGS COULD BE MORE
DICEY. RFD FOR INSTANCE HAS 7 INCHES OF SNOW ON THE GROUND...AND
THE WAA ADVECTION AND NEAR FREEZING TEMPS ON FRIDAY MAY NOT MAKE A
SIGNIFICANT DENT IN THE SNOW. AS SUCH WENT NEAR GUIDANCE FOR
THESE NORTHERN AREAS WITH TEMPS JUST ABOVE FREEZING FRIDAY...AND
AROUND 40 SATURDAY. COULD CERTAINLY SEE A TIGHT TEMP GRADIENT
WITHIN THE CWA AS THE SNOW FREE AREAS WARM QUICKLY...WHILE THE AREAS
WITH SNOW PACK STRUGGLE TO CLIMB.
EXTENDED...SUNDAY THROUGH TUESDAY...
THE SURFACE LOW SINKS SOUTH...MOVING OVER THE CWA SATURDAY NIGHT
INTO SUNDAY. AN UPPER LEVEL STREAMER ASSOCIATED WITH THE LOW
WEAKENS AS THE STRONGER UPPER LEVEL TROUGH CATCHES UP WITH THE LOW.
PRECIP IS EXPECTED ALONG AND BEHIND THE COLD FRONT. GUIDANCE
DIFFERS A BIT ON THE TIMING OF THE LOW AND AS TO HOW MUCH FORCING
WILL ACCOMPANY IT. THE GFS IS MORE VIGOROUS THAN THE ECMWF WITH
PRECIP...WHILE THE ECMWF IS A BIT FASTER. AS SUCH LEFT POPS IN THE
CHANCE RANGE UNTIL THE FORCING AND TIMING ASPECTS BECOME A BIT
CLEARER. OVERALL NOT EXPECTING A LOT OF PRECIP/SNOW.
THE BIGGER STORY WILL BE TEMPS. TEMPS WILL FALL SUNDAY AS COLD AIR
CONTINUES TO FUNNEL IN BEHIND THE TROUGH AXIS. 925MB TEMPS FALL TO
-4 TO -14C ALOFT BY SUNDAY EVENING WITH COLDER AIR EXPECTED
OVERNIGHT. HIGH PRESSURE ALSO APPROACHES FROM THE WEST SO CLEARING
SKIES AND NORTHWEST WINDS AROUND 10 KT WILL LEAD TO A VERY COLD
NIGHT. LOW TEMPS WILL RANGE FROM BELOW ZERO OVER NORTH CENTRAL IL TO
SINGLE DIGITS OVER NW INDIANA. MIN WIND CHILLS BELOW -20 ARE STILL
EXPECTED ACROSS NORTH CENTRAL IL SUNDAY NIGHT AND MONDAY NIGHT.
COLD CONTINUES THROUGH NEW YEARS EVE WITH A SLIGHT RELIEF EXPECTED
ON JAN 1ST. GUIDANCE CONTINUES TO HINT AT A PRECIP SYSTEM
TUESDAY...BUT GUIDANCE IS LESS CLEAR ON FORCING AND TIMING TODAY
COMPARED TO YESTERDAY. THEREFORE LEFT SLIGHT CHANCE TO CHANCE POPS
IN THROUGH MID WEEK.
JEE
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 16Z...
* BAND OF LIGHT SNOW/FLURRIES THIS MORNING...AND PERIODS OF MVFR
VSBY PSBL.
* TIMING OF NEXT CLIPPER SNOW STAYING NORTH OF ORD/MDW LATER
THIS AFTERNOON/EVENING (BUT NOT BY MUCH)
ED F/BMD
//DISCUSSION...UPDATED 12Z...
FAST NORTHWEST FLOW ALOFT CONTINUES TODAY WITH ANOTHER UPPER LEVEL
DISTURBANCE POISED TO PASS BY NORTH OF THE LOCAL AREA LATE THIS
AFTERNOON AND THIS EVENING. AREAS OF MID LEVEL CLOUDINESS
STREAMING ESE IN THIS FAST FLOW ALOFT AHEAD OF THIS DISTURBANCE
WILL MOVE ACROSS THE TERMINALS THIS MORNING AND AFTERNOON.
GOOD SIZED AREA OF 3000-4000 FT SC CLOUD DECK OVER IOWA EXPECTED
TO ALSO ADVECT INTO ILLINOIS THIS MORNING. MAY SEE CIGS BRIEFLY GO
BELOW 3000 FT WITH THIS CLOUD DECK.
WINDS HAVE SLACKENED FROM PRE-DAWN GUSTINESS AS MAX OF PRESSURE
RISES NOW OVERHEAD AND SLIDING OFF TO OUR EAST AND SURFACE RIDGE
AXIS APPROACHING. EXPECT WINDS TO REMAIN AROUND 10 KT OR LESS
REMAINDER OF THE DAY. AFOREMENTIONED UPPER DISTURBANCE WILL
ENHANCE CLOUDINESS LATE THIS AFTERNOON AND MAY BRING A PASSING
FLURRY. ANY ACCUMULATING SNOW IS EXPECTED TO STAY NORTH OF ORD/MDW
TONIGHT.
ED F
//ORD AND MDW CONFIDENCE...UPDATED 16Z...
* MEDIUM TO HIGH CONFIDENCE ON WIND TRENDS.
* LOW TO MEDIUM CONFIDENCE ON CLOUD TRENDS
* MEDIUM TO HIGH CONFIDENCE IN SNOW THIS MORNING WITH PERIODS OF
MVFR VSBY. MEDIUM CONFIDENCE THAT SNOW THAT WOULD RESTRICT
VISIBILITY WILL STAY NORTH OF ORD/MDW LATER THIS
AFTERNOON/EVENING.
ED F/BMD
//OUTLOOK FOR ORD/MDW FOR 00Z SATURDAY-12Z THURSDAY...UPDATED 12Z...
FRIDAY NIGHT...VFR WIND.
SATURDAY...VFR WIND.
SUNDAY THROUGH TUESDAY NIGHT...PERIODS OF -SN WITH OCNL MVFR
CIGS/VSBY. A PERIOD OF IFR CIGS/VIS POSSIBLE.
WEDNESDAY...VFR WX NIL.
ED F
&&
.MARINE...
327 AM CST
AN ACTIVE PERIOD ON LAKE MICHIGAN WEATHER WISE ON TAP FOR THE
NEXT 5 DAYS AS THE AREA REMAINS UNDER THE INFLUENCE OF FAST
NORTHWEST FLOW ALOFT THAT BECOMES ZONAL BRIEFLY FRIDAY-SATURDAY.
THIS WILL SET THE STAGE FOR A COUPLE OF SEPARATE SYSTEMS TO
POSSIBLY PRODUCE MULTIPLE PERIODS OF GALE FORCE WINDS FRIDAY
THROUGH SUNDAY. LOW PRESSURE DEPARTING THE AREA TODAY WILL BE
REPLACED WITH A RIDGE AXIS SLIDING EAST ACROSS THE LAKE THIS
EVENING. LOW PRESSURE WILL THEN MOVE OUT OF SASKATCHEWAN TO
NORTHERN LAKE SUPERIOR BY FRIDAY EVENING. THE STRONG PRESSURE
CONTRAST BETWEEN THIS LOW AND HIGH PRESSURE TO THE SOUTHEAST WILL
LIKELY RESULT IN GALE FORCE WINDS FOR A PERIOD LATE FRIDAY/FRIDAY
NIGHT.
UNCERTAINTY SURROUNDING A SECOND AREA OF LOW PRESSURE POTENTIALLY
STRONGER MOVING OUT OF THE PLAINS AND INTO THE WESTERN GREAT LAKES
BY EARLY SUNDAY WILL SET THE STAGE FOR ADDITIONAL PERIODS OF GALES
POSSIBLY SATURDAY AND SUNDAY DEPENDING ON HOW EXACTLY THIS LOW
EVOLVES. AT THE SAME TIME WINDS CLOSER TO THE TRACK OF THE LOW
ITSELF WILL BE LIGHTER. MOST ANY FORECAST BUT THIS ONE IN
PARTICULAR WILL BE BEST MONITORED VIA THE GRAPHICAL FORECASTS
AVAILABLE ON THE WEB AT WWW.WEATHER.GOV/GREATLAKES IN ORDER TO SEE
THE RICHNESS OF THE DETAIL EXPECTED GIVEN THIS COMPLEX SITUATION.
ED F
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...NONE.
&&
$$
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Area Forecast Discussion
National Weather Service Lincoln IL
958 AM CST Thu Dec 26 2013
.DISCUSSION...
ISSUED 958 AM CST Thu Dec 26 2013
Lingering area of altocumulus clouds about to exit the northeast
CWA, however another batch covers most of Iowa and is headed
southeast. Latest RAP model shows this spreading over the northern
half of the forecast area this afternoon. Recent zone/grid updates
mainly were done to reflect the latest cloud trends. Temperatures
currently on track and required little change other than the usual
hourly trend tweaks.
Geelhart
&&
.AVIATION...
ISSUED 559 AM CST Thu Dec 26 2013
VFR conditions should continue over the next 24 hours, as clippers
pass by just to the north of the area. Those weather disturbances
will bring mainly mid-level clouds over our terminal sites today
and tonight. No precipitation is expected, due to the amount of
dry air in the lowest levels of the atmosphere.
Winds will begin from the west early this morning, then become
southwest as high surface pressure passes by to the south of IL
and low pressure moves across the upper Midwest. Pressure
gradients will support wind speeds increasing into the 10-14kt
range today, which will maintain for much of the evening before
dropping below 10kt later tonight.
Shimon
&&
.PREV DISCUSSION...
ISSUED 207 AM CST Thu Dec 26 2013
SHORT TERM...Today through Saturday
Next short-wave embedded within the progressive northwesterly flow
pattern is evident on 08z/2am water vapor imagery over southern
Saskatchewan/northern Montana. As has been advertised for the past
few model runs, this wave will remain a bit further north than the
previous ones. This will keep any light snow or flurries well to
the north across Wisconsin and far northern Illinois today, while
central Illinois only sees a few clouds. Latest IR satellite imagery
shows skies clearing out in the wake of the previous disturbance:
however, plenty of cloud cover is poised just upstream ahead of
the next wave. Based on satellite trajectories, it appears clouds
will overspread much of the central and northern KILX CWA, while
skies remain mostly clear further south. Will be a fairly mild day
as well, with southerly winds allowing temps to rise a degree or
two higher than yesterday, mainly reaching the middle 30s.
Once short-wave passes tonight, upper flow will briefly become
zonal Friday into Saturday, leading to a considerable warming
trend. With 850mb temps progged to reach the 6 to 8C range, high
temps will likely climb well into the 40s and perhaps even the
lower 50s across the southeast CWA on Saturday.
LONG TERM...Sunday through Wednesday
The warmer weather will be short-lived however, as a significant
trough digs across the central/eastern CONUS early next week,
sending an Arctic cold front through central Illinois. Models
continue to suggest a band of post-frontal precip on Sunday. Given
the strength of the boundary and the approaching upper wave, will
mention a chance for snow as the front passes. Little or no
accumulation is expected, as system will have only limited
moisture to work with and will be moving rather fast. Once front
clears the area, sharply colder conditions are expected on Monday.
850mb temps drop to between -12 and -14C, resulting in highs temps
plunging into the teens.
Clipper system for early next week still remains in question, with
the 00z Dec 26 models exhibiting a 24-hour timing discrepancy.
ECMWF shows system skirting through central Illinois Monday/Monday
night, while the GFS delays it until Tuesday/Tuesday night. This
is a marked change for the ECMWF and given the fact that the GEM
more closely resembles the GFS solution, will stick with the GFS
in the extended. As a result, will continue with cold/dry weather
on Monday, then will bring snow chances into the area Tuesday and
Tuesday night. At this point, it appears greatest chance for
accumulating snow will mainly be confined to the northern half of
the CWA, but this will likely be fine-tuned as models gradually get
a better handle on the wave.
Barnes
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS GOODLAND KS
145 PM MST THU DEC 26 2013
.SHORT TERM...(THIS EVENING THROUGH FRIDAY)
ISSUED AT 1258 PM MST THU DEC 26 2013
A WEAK UPPER LEVEL SHORTWAVE TROUGH DROPPING SOUTH/SOUTHEAST ACROSS
THE HIGH PLAINS BROUGHT SOME CLOUD COVER TO THE REGION THIS MORNING.
LIMITED MID-LEVEL MOISTURE ASSOCIATED WITH THIS DISTURBANCE AND
UNFAVORABLE DYNAMICS MEANS NO PRECIPITATION WITH THIS EVENT.
TOMORROW WILL LIKELY BE THE WARMEST DAY OF THE WEEK FOR MOST
LOCATIONS THANKS TO LOW/MID-LEVEL WARM AIR ADVECTION AND SUNNY SKIES.
HAPPY TO SEE THE NCEP SNOW DEPTH ASSIMILATION DID A PRETTY GOOD JOB
WITH ITS 06Z DAILY UPDATE...REMOVING ALL BUT A SMALL PATCH OF SNOW
COVER IN NORTHEAST RED WILLOW AND WESTERN FURNAS COUNTIES IN NEBRASKA.
SO HAVE MORE CONFIDENCE IN 06Z/12Z CYCLE GUIDANCE IN SW NEBRASKA THAN
EARLIER CYCLES WHICH HAD A WIDE SWATH OF SNOW COVER ACROSS ALL OF SW
NEB AND NORTHEAST COLORADO...WHICH INFLUENCED LOW-LEVEL MODEL TEMP
AND MOISTURE FIELDS /QUITE DRAMATICALLY IN THE CASE OF THE NAM/.
TODAY...THURSDAY...MOSTLY SUNNY AND MILD WITH A LIGHT BREEZE.
DISTURBANCE MOVING SOUTH/SOUTHEAST ACROSS THE HIGH PLAINS THE CAUSE
FOR THE MID/HIGH-LEVEL CLOUDS TODAY. CLOUDS ARE THINNING OUT FROM
EARLIER THIS MORNING WHEN THE WERE OVER WESTERN NEBRASKA AND EASTERN
WYOMING...AND WHILE THE RAP IS A LITTLE AGGRESSIVE ABOUT DEVELOPING
THICKER MID-LEVEL CLOUDS THIS AFTERNOON ALONG I70 BELIEVE THE CLOUD
COVER WILL HAVE MINIMAL IMPACT ON HIGH TEMPS TODAY. WITH THE SURFACE
TROUGH OVER EASTERN COLORADO AND UPPER LEVEL DISTURBANCE MOVING THROUGH
EXPECT ANOTHER DAY OF BREEZY WINDS...DECREASING LATE IN THE
AFTERNOON. PREVIOUS FORECAST HIGHS WERE NUDGED UP JUST A TAD TO
ACCOUNT FOR LESS CLOUD COVER BASED ON HOURLY TEMP TREND THUS FAR.
TONIGHT...A FEW HIGH CLOUDS AND NEAR NORMAL TEMPS. SIMILAR TO LAST
NIGHT LIGHT WINDS ARE EXPECTED TO CONTINUE THROUGH THE NIGHT...AND
GIVEN THE DIRECTION /WESTERLY/ AND THE LOW/MID-LEVEL WARM AIR
ADVECTION THINK MANY SPOTS WILL NOT DIP BELOW THE LOW 20S. /EXCEPT
FOR THE USUAL COLD SPOTS SUCH AS WESTERN CHEYENNE COUNTY COLORADO./
TOMORROW...FRIDAY...SUNNY AND WARM. THE WEAK SURFACE TROUGH ACROSS
EASTERN COLORADO REMAINS IN PLACE AS A BROAD H5 LONGWAVE RIDGE
APPROACHES FROM THE WEST. WINDS WILL BE LIGHT OUT OF THE
WEST/SOUTHWEST...ONLY AIDING IN THE WARMTH. HIGHS WILL BE IN THE LOW
TO MID 60S BASED ON CURRENT GUIDANCE. THE RECORD HIGH AT BURLINGTON
COLORADO MAY BE IN JEOPARDY...WHICH CURRENTLY STANDS AT 65 SET IN
1976. /ELSEWHERE RECORDS ARE WELL ABOVE FORECAST HIGHS./
.LONG TERM...(FRIDAY NIGHT THROUGH THURSDAY)
ISSUED AT 145 PM MST THU DEC 26 2013
FRIDAY NIGHT-SUNDAY...CONTINUED WARM AND DRY SATURDAY AHEAD OF AN
UPPER TROUGH THAT MOVES THROUGH SATURDAY NIGHT. ON SUNDAY FORECAST
AREA UNDER NORTHWEST FLOW ALOFT. AHEAD OF THE UPPER TROUGH STRONG
NORTH/NORTHWEST WINDS MOVE IN EARLY SATURDAY AFTERNOON WITH
SUSTAINED SPEEDS AROUND 20-30 MPH WITH HIGHER GUSTS. SOME GUSTY
WINDS CONTINUE THROUGH EARLY SATURDAY NIGHT BEFORE SLOWLY DECREASING
AFTER MIDNIGHT AND THROUGH THE DAY SUNDAY. CANT COMPLETELY RULE OUT
SOME VERY LIGHT PRECIPITATION CHANCES EARLY SATURDAY NIGHT AS BETTER
MOISTURE BUT LIMITED DYNAMICS WITH THE UPPER TROUGH MOVE THROUGH.
AFTER MIDNIGHT MOISTURE QUICKLY MOVES AWAY FROM THE AREA WITH NEAR
ZERO CHANCE ON SUNDAY.
LOWS TONIGHT UPPER TEENS TO MID 20S WITH HIGHS SATURDAY MID 50S TO
LOW 60S. LOWS SATURDAY NIGHT IN THE TEENS WITH MID 20S (EAST) TO
LOW/MID 30S FAR WEST SUNDAY.
SUNDAY NIGHT-THURSDAY...FORECAST AREA REMAINS UNDER NORTHWEST FLOW
ALOFT THROUGH THE PERIOD. WEATHER SYSTEMS MOVE THROUGH THE FLOW
SUNDAY NIGHT THEN AGAIN MONDAY NIGHT AND TUESDAY NIGHT.
HOWEVER...DOESNT LOOK LIKE ANY OF THESE PRODUCE ANY PRECIPITATION.
TEMPERATURES SLOWLY WARM MONDAY AND TUESDAY BEFORE COOLING DOWN
WEDNESDAY AND THEN WARMING UP AGAIN THURSDAY.
LOWS SUNDAY NIGHT IN THE TEENS WITH LOW TO MID 20S MONDAY
NIGHT-WEDNESDAY NIGHT. HIGHS MONDAY LOW TO MID 40S ALTHOUGH
GFS/ECMWF 850 TEMPS SUPPORT READINGS A BIT HIGHER. FOR TUESDAY LOW
TO MID 40S EAST WITH UPPER 40S TO LOW 50S WEST. ON WEDNESDAY AN
UNCERTAIN LOW TO MID 40S AS DIFFERENCES SHOW UP IN JUST HOW MUCH
COOLER IT WILL BE WITH LARGE DISPARITY BETWEEN ECMWF/GFS 850
TEMPERATURES. FOR THURSDAY GENERALLY MID TO UPPER 40S...ECMWF
SUGGESTS IT WILL BE WARMER THEN CURRENT FORECAST PER 850
TEMPERATURES WHILE GFS ABOUT 5C COOLER.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z FRIDAY AFTERNOON)
ISSUED AT 1030 AM MST THU DEC 26 2013
VFR CONDITIONS WILL PERSIST THROUGH THE TAF PERIOD AT GLD AND MCK. A
FEW MID/HIGH CLOUDS POSSIBLE THIS AFTERNOON AT GLD AS AN UPPER LEVEL
DISTURBANCE MOVES ACROSS THE REGION. BREEZY AT TIMES THIS AFTERNOON
SIMILAR TO YESTERDAY WITH WINDS 12 TO 18 KTS OUT OF THE NORTHWEST
WITH A FEW GUSTS UP TO 25 KTS POSSIBLE. OVERNIGHT WINDS WILL BACK
TO THE WEST WITH A LIGHT WIND CONTINUING THROUGH THE NIGHT AS HAS
BEEN THE PATTERN THE PAST FEW NIGHTS...THOUGH NOT AS INTENSE.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
CO...NONE.
NE...NONE.
&&
$$
SHORT TERM...JJM
LONG TERM...99
AVIATION...JJM
AREA FORECAST DISCUSSION
NWS GOODLAND KS
1258 PM MST THU DEC 26 2013
.SHORT TERM...(THIS EVENING THROUGH FRIDAY)
ISSUED AT 1258 PM MST THU DEC 26 2013
A WEAK UPPER LEVEL SHORTWAVE TROUGH DROPPING SOUTH/SOUTHEAST ACROSS
THE HIGH PLAINS BROUGHT SOME CLOUD COVER TO THE REGION THIS MORNING.
LIMITED MID-LEVEL MOISTURE ASSOCIATED WITH THIS DISTURBANCE AND
UNFAVORABLE DYNAMICS MEANS NO PRECIPITATION WITH THIS EVENT.
TOMORROW WILL LIKELY BE THE WARMEST DAY OF THE WEEK FOR MOST
LOCATIONS THANKS TO LOW/MID-LEVEL WARM AIR ADVECTION AND SUNNY SKIES.
HAPPY TO SEE THE NCEP SNOW DEPTH ASSIMILATION DID A PRETTY GOOD JOB
WITH ITS 06Z DAILY UPDATE...REMOVING ALL BUT A SMALL PATCH OF SNOW
COVER IN NORTHEAST RED WILLOW AND WESTERN FURNAS COUNTIES IN NEBRASKA.
SO HAVE MORE CONFIDENCE IN 06Z/12Z CYCLE GUIDANCE IN SW NEBRASKA THAN
EARLIER CYCLES WHICH HAD A WIDE SWATH OF SNOW COVER ACROSS ALL OF SW
NEB AND NORTHEAST COLORADO...WHICH INFLUENCED LOW-LEVEL MODEL TEMP
AND MOISTURE FIELDS /QUITE DRAMATICALLY IN THE CASE OF THE NAM/.
TODAY...THURSDAY...MOSTLY SUNNY AND MILD WITH A LIGHT BREEZE.
DISTURBANCE MOVING SOUTH/SOUTHEAST ACROSS THE HIGH PLAINS THE CAUSE
FOR THE MID/HIGH-LEVEL CLOUDS TODAY. CLOUDS ARE THINNING OUT FROM
EARLIER THIS MORNING WHEN THE WERE OVER WESTERN NEBRASKA AND EASTERN
WYOMING...AND WHILE THE RAP IS A LITTLE AGGRESSIVE ABOUT DEVELOPING
THICKER MID-LEVEL CLOUDS THIS AFTERNOON ALONG I70 BELIEVE THE CLOUD
COVER WILL HAVE MINIMAL IMPACT ON HIGH TEMPS TODAY. WITH THE SURFACE
TROUGH OVER EASTERN COLORADO AND UPPER LEVEL DISTURBANCE MOVING THROUGH
EXPECT ANOTHER DAY OF BREEZY WINDS...DECREASING LATE IN THE
AFTERNOON. PREVIOUS FORECAST HIGHS WERE NUDGED UP JUST A TAD TO
ACCOUNT FOR LESS CLOUD COVER BASED ON HOURLY TEMP TREND THUS FAR.
TONIGHT...A FEW HIGH CLOUDS AND NEAR NORMAL TEMPS. SIMILAR TO LAST
NIGHT LIGHT WINDS ARE EXPECTED TO CONTINUE THROUGH THE NIGHT...AND
GIVEN THE DIRECTION /WESTERLY/ AND THE LOW/MID-LEVEL WARM AIR
ADVECTION THINK MANY SPOTS WILL NOT DIP BELOW THE LOW 20S. /EXCEPT
FOR THE USUAL COLD SPOTS SUCH AS WESTERN CHEYENNE COUNTY COLORADO./
TOMORROW...FRIDAY...SUNNY AND WARM. THE WEAK SURFACE TROUGH ACROSS
EASTERN COLORADO REMAINS IN PLACE AS A BROAD H5 LONGWAVE RIDGE
APPROACHES FROM THE WEST. WINDS WILL BE LIGHT OUT OF THE
WEST/SOUTHWEST...ONLY AIDING IN THE WARMTH. HIGHS WILL BE IN THE LOW
TO MID 60S BASED ON CURRENT GUIDANCE. THE RECORD HIGH AT BURLINGTON
COLORADO MAY BE IN JEOPARDY...WHICH CURRENTLY STANDS AT 65 SET IN
1976. /ELSEWHERE RECORDS ARE WELL ABOVE FORECAST HIGHS./
.LONG TERM...(SUNDAY THROUGH WEDNESDAY)
ISSUED AT 318 AM MST THU DEC 26 2013
SUNDAY THROUGH WEDNESDAY...NOT MUCH CHANGE WITH THE LARGE SCALE
PATTERN. A SHORTWAVE TROUGH WILL MOVE THROUGH THE CWA ON SUNDAY AND
COLD AIR WILL FILTER INTO THE CWA WITH A SURFACE HIGH. AS THE
SURFACE HIGH MOVES IN BEHIND THE LEE TROUGH TO THE SOUTH...NORTH
WINDS MAY REMAIN FAIRLY BREEZY ON SUNDAY MORNING. INCREASED WINDS
SLIGHTLY IN THE EASTERN PORTION OF THE CWA AT THE 12Z AND 18Z TIME
FRAMES. CLOUD COVER SHOULD BEGIN TO DECREASE ON SUNDAY MID-DAY INTO
THE AFTERNOON.
A LARGE UPPER TROUGH WILL BE OVER THE EASTERN U.S. AND MIDWEST AND
AN UPPER RIDGE WILL RESIDE OVER THE WESTERN U.S. WITH THE CWA UNDER
NORTHWEST FLOW ALOFT...BEING IN-BETWEEN LARGE SCALE FEATURES SUNDAY
THROUGH WEDNESDAY. ANOTHER MID-UPPER SHORTWAVE TROUGH WILL MOVE
THROUGH THE CWA ON TUESDAY NIGHT INTO WEDNESDAY. A WEAK COLD FRONT
WILL PASS THROUGH AHEAD OF THE SHORTWAVE TROUGH DURING THIS
TIME...DROPPING TEMPERATURES SLIGHTLY IF MUCH AT ALL. PRECIPITATION IS
NOT REALLY EXPECTED WITH THIS WAVE AS SOUNDINGS SHOW THE MID-LEVELS
SATURATED BUT DRIER TOWARDS THE SURFACE. AN INCREASE IN MID-LEVEL
CLOUD COVER CAN BE EXPECTED...BUT THE FORECAST WAS KEPT DRY AT THE
MOMENT.
TEMPERATURES IN THE EXTENDED WILL BE BELOW NORMAL TO START ON SUNDAY
...WITH HIGHS IN THE UPPER 20S TO MID 30S AND LOWS IN THE TEENS
SUNDAY NIGHT...AND WILL BE NEAR TO ABOVE NORMAL THROUGHOUT THE
REMAINDER OF THE EXTENDED. HIGHS MONDAY THROUGH TUESDAY WILL
STEADILY INCREASE FROM THE LOW TO MID 40S ON MONDAY INTO THE UPPER
40S TO LOW 50S ON TUESDAY. THE WEAK FRONT MOVING THROUGH ON TUESDAY NIGHT
WILL ONLY SLIGHTLY AFFECT HIGHS ON WEDNESDAY...REACHING THE MID TO
UPPER 40S WITH SOME LOCATIONS NEAR 50. THE COLD FRONT MAY TRACK
FURTHER EAST...WHICH COULD HAVE EVEN LESS OF AN EFFECT ON HIGH
TEMPERATURES FOR DAY 7.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z FRIDAY AFTERNOON)
ISSUED AT 1030 AM MST THU DEC 26 2013
VFR CONDITIONS WILL PERSIST THROUGH THE TAF PERIOD AT GLD AND MCK. A
FEW MID/HIGH CLOUDS POSSIBLE THIS AFTERNOON AT GLD AS AN UPPER LEVEL
DISTURBANCE MOVES ACROSS THE REGION. BREEZY AT TIMES THIS AFTERNOON
SIMILAR TO YESTERDAY WITH WINDS 12 TO 18 KTS OUT OF THE NORTHWEST
WITH A FEW GUSTS UP TO 25 KTS POSSIBLE. OVERNIGHT WINDS WILL BACK
TO THE WEST WITH A LIGHT WIND CONTINUING THROUGH THE NIGHT AS HAS
BEEN THE PATTERN THE PAST FEW NIGHTS...THOUGH NOT AS INTENSE.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
CO...NONE.
NE...NONE.
&&
$$
SHORT TERM...JJM
LONG TERM...ALW
AVIATION...JJM
AREA FORECAST DISCUSSION
NWS JACKSON KY
105 PM EST THU DEC 26 2013
.UPDATE...
ISSUED AT 105 PM EST THU DEC 26 2013
CLOUDS HAVE QUICKLY SCOURED OUT ACROSS THE AREA WITH SUNSHINE
EXPECTED THROUGH THE REST OF THE AFTERNOON. NO CHANGES NEEDED AT THIS
TIME.
UPDATE ISSUED AT 940 AM EST THU DEC 26 2013
A BAND OF SHALLOW LOW CLOUDS CONTINUES TO PUSH SOUTHEAST THIS MORNING
ACROSS EASTERN KENTUCKY. HOWEVER...THESE CLOUDS ARE ALREADY
DEVELOPING HOLES AND STARTING TO ERODE. THIS TREND SHOULD CONTINUE AS
WE HEAD TOWARDS SUNNY SKIES THIS AFTERNOON. WILL INCREASE SKY COVER
OVER THE NEXT FEW HOURS FOR THE SOUTHEAST...BEFORE GOING MAINLY SUNNY
BY THIS AFTERNOON. HAVE ALSO LOWERED RELATIVE HUMIDITY SLIGHTLY GIVEN
THE DECENT MIXING POTENTIAL UNDER THE SUNNY SKIES THIS AFTERNOON.
UPDATED FORECAST IS ALREADY OUT.
UPDATE ISSUED AT 715 AM EST THU DEC 26 2013
UPDATED THE GRIDS TO FINE TUNE TEMPERATURES...MAINLY MILDER...FOR THE
NEXT SEVERAL HOURS PER LATEST OBS AND TRENDS. DID ALSO ADJUST SKY
COVER TO BRING THE POST FRONTAL SC FURTHER SOUTH AND EAST FOR THE
FIRST PART OF THE MORNING...BUT STILL EXPECT THESE TO BE MOSTLY GONE
BY NOON. THE GRIDS HAVE BEEN SENT TO THE NDFD AND WEB SERVERS.
&&
.SHORT TERM...(TODAY THROUGH FRIDAY)
ISSUED AT 335 AM EST THU DEC 26 2013
07Z SFC ANALYSIS SHOWS A MOSTLY DRY COLD FRONT CROSSING EAST
KENTUCKY. THIS IS ACCOMPANIED BY A LOWER DECK OF CLOUDS AND SOME
RETURNS ON RADAR...MOSTLY VIRGA. LOWER CLOUDS...NEAR MVFR...TRAIL
THIS BOUNDARY AND WILL MOVE OVER THE NORTHERN TWO THIRDS OF THE CWA
INTO THE FIRST PART OF THE MORNING. THIS SHOULD KEEP TEMPERATURES
FROM FALLING MUCH FURTHER THROUGH THE AREA INTO DAWN. CURRENTLY THEY
VARY FROM THE UPPER 20S IN SOME VALLEYS TO THE MID 30S ON THE
RIDGES...WHILE DEWPOINTS ARE GENERALLY IN THE LOW AND MID 20S.
THE MODELS ARE IN GOOD ENOUGH AGREEMENT ALOFT THROUGH THE SHORT TERM
AS THEY ALL TAKE A SHARP SHORTWAVE NORTHEAST AND AWAY FROM THE OHIO
VALLEY TODAY. LATER...ANOTHER RIPPLE MOVES THROUGH THE BASE OF THE
RETREATING LARGE EAST CANADIAN TROUGH...PASSING HARMLESSLY THROUGH
THE AREA MIDDAY FRIDAY. HEIGHTS WILL THEN RISE OVER THE STATE AHEAD
OF A BROAD AND UNCONSOLIDATED AREA OF LOWER ONES ASSOCIATED WITH THE
POOLING ENERGY OVER SOUTH CENTRAL TEXAS. THE MODELS ARE HAVING THE
MOST DIFFICULTIES WITH THIS FEATURE AS THE NAM IS OUT OF STEP WITH
THE OTHERS IN KEEPING THE RESULTANT MID LEVEL LOW WEAKER AND A NOTCH
FURTHER EAST THAN CONSENSUS. THESE DIFFERENCES WILL AFFECT THE
FORECAST OVER THE WEEKEND...BEYOND THE SHORT TERM SO THE NAM12 WAS
PRIMARILY USED...ALONG WITH THE LATEST HRRR FOR THE NEAR TERM WX...
TO GUIDE THIS PART OF THE FORECAST.
SENSIBLE WEATHER WILL FEATURE A FLEETING CHANCE OF MAINLY FLURRIES
PASSING THROUGH FAR EAST KENTUCKY OVER THE NEXT COUPLE OF HOURS.
OTHERWISE...IT WILL BE A DRY AND QUIET FORECAST TO END THE WORK WEEK
AS SFC HIGH PRESSURE IS BUFFETED BY PASSING MID LEVEL WAVES AND
THEIR SFC REFLECTIONS TO THE NORTH OF THE AREA. THIS WILL BE NOTED
MAINLY IN TIMES OF MID AND HIGH CLOUDS BRUSHING PAST THE CWA.
TEMPERATURES THROUGH EAST KENTUCKY WILL BE SEASONABLY NEAR NORMAL
WHILE WE AWAIT THE SOUTHERN DEVELOPMENT FOR A SHOT AT A RETURN OF
PCPN LATER IN THE WEEKEND.
FOLLOWED THE CONSSHORT AND ITS BC PARTNER FOR T...TD...AND WINDS
THROUGH 12Z FRIDAY WITH SOME BLENDING IN WITH THE DIURNAL FROM THE
NAM12 FOR HOURLY TEMPS. OTHERWISE...THE CONSALL WAS USED AS A
STARTING POINT. DID ADD IN SOME MINOR RIDGE AND VALLEY TEMPERATURE
DIFFERENCES TONIGHT WHILE KEEPING POPS IN THE LOW SINGLE DIGITS AT
BEST...IN LINE WITH MOS...OUTSIDE OF THE NEXT FEW HOURS IN THE FAR
EAST.
.LONG TERM...(FRIDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 330 AM EST THU DEC 26 2013
THE BEGINNING OF THE EXTENDED PERIOD /12Z SATURDAY/ WILL HOST ZONAL
FLOW ALOFT AND SURFACE HIGH PRESSURE...MAKING FOR CLEAR SKIES IN THE
MORNING. HOWEVER...THIS SET UP WILL BE SHORT LIVED...AS TWO SYSTEMS
WILL BEGIN TO INTERACT ON EASTERN KY OVER THE NEXT 24 TO 36 HOURS.
THE FIRST OF THESE SYSTEMS...A STRONG UPPER LEVEL SHORTWAVE ACROSS
THE SOUTHERN PLAINS MOVING SLOWLY NEWARD. A SURFACE LOW PRESSURE
SYSTEM WILL DEVELOP SLIGHTLY EASTWARD OF THE UPPER TROUGH...PULLING
IN MOISTURE OFF THE GULF OF MEXICO ACROSS THE SOUTHERN STATES AND
THEN INTO SOUTHERN AND EASTERN KY SATURDAY NIGHT/SUNDAY MORNING. THE
SECOND SHORTWAVE WILL BE SLIGHTLY WEAKER...MOVING IN JUST BEHIND AND
NORTH OF THE ORIGINAL WAVE. THIS WILL PUSH A COLD FRONT ACROSS
KY FROM THE NW MONDAY EVENING/NIGHT. OF THE TWO...EXPECT THE BEST
PRECIP CHANCES AND QPF TO COME FROM THE FIRST SYSTEM...BEGINNING
RIGHT BEFORE 6Z SUNDAY AND CONTINUING THROUGH SUNDAY
AFTERNOON/EVENING. THEN THE SECOND WAVE OF MOISTURE BEGINS TO HIT KY
FROM THE NORTH AND WEST SUNDAY NIGHT INTO MONDAY. THIS TIME THE
PRECIP WILL BE LIGHTER AND SCATTERED IN NATURE.
UNFORTUNATELY...MODELS ARE STILL NOT COMPLETELY AGREEING ON THEIR
TIMING AND SET UP...SO WILL CONTINUE WITH THE ALLBLEND OUTPUT AT
THIS TIME FOR POPS.
WITH A WARM PULL FROM THE SOUTH AHEAD OF THESE TWO SYSTEMS...TEMPS
WILL RISE TO ABOVE NORMALS SATURDAY AND SUNDAY /UPPER 40S AND LOW
50S/. HOWEVER...ONCE THE COLD FRONT ACCOMPANYING THE SECOND SYSTEM
PUSHES THROUGH...IT WILL USHER IN COLDER AIR FROM THE NW.
TEMPERATURE DIFFERENCES COULD BE AS MUCH AS 15 DEGREES COOLER FROM
SUNDAY INTO MONDAY...FALLING NEAR FREEZING FOR HIGHS. THIS
TEMPERATURE DROP WILL BE WHAT GOVERNS RAIN VS. SNOW WITH THIS SECOND
SYSTEM. AT PRESENT...HAVE ALL RAIN IN FORECAST UNTIL AROUND
MIDNIGHT...AT WHICH POINT A RAIN AND SNOW MIX WILL BE
POSSIBLE...BEFORE TEMPS DROP ENOUGH TO GOVERN ALL SNOW BY 9Z.
PROLONGED TIME PERIOD FOR WHICH ACCUMULATIONS COULD OCCUR COMPARED
TO PREVIOUS FORECAST...BUT DID DROP AMOUNTS SLIGHTLY IN THE WESTERN
HALF OF THE CWA. ANYWHERE BETWEEN A DUSTING TO A COUPLE TENTHS OF AN
INCH WILL BE POSSIBLE ACROSS MUCH THE CWA...WITH THE HIGHER TERRAIN
EXPECTED TO SEE A BIT MORE...BETWEEN A HALF AN INCH TO ONE INCH.
OBVIOUSLY THIS SYSTEM IS FAIRLY FAR OUT IN THE FORECAST...SO EXPECT
THESE TOTALS TO CONTINUE TO CHANGE AS WE GET CLOSER TO THE ONSET.
WITH A TROUGHING PATTERN SETTING UP ACROSS THE EASTERN U.S...COULD
SEE SEVERAL MORE SHORTWAVES MOVE THROUGH THE TROUGH OVER THE FEW
DAYS FOLLOWING. AT THIS TIME...MODEL SOLUTIONS ARE KEEPING ANY
MOISTURE RELATED TO THESE SHORTWAVES AWAY FROM EASTERN KY. THAT
BEING SAID...TUESDAY NIGHT/WEDNESDAY MORNING WILL BE A TIME FRAME TO
WATCH...AS ANY VARIATIONS SOUTHWARD FROM WHERE THE BLENDED RUN
PLACES THE SYSTEM...KJKL COULD SEE PRECIPITATION.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z FRIDAY AFTERNOON)
ISSUED AT 105 PM EST THU DEC 26 2013
VFR CONDITIONS WILL REMAIN ACROSS EASTERN KENTUCKY OVER THE NEXT 24
TO 36 HOURS WITH LIGHT WINDS.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...KAS
SHORT TERM...GREIF
LONG TERM...JMW
AVIATION...KAS
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
601 PM EST THU DEC 26 2013
.SHORT TERM...(THIS EVENING THROUGH FRIDAY)
ISSUED AT 511 PM EST THU DEC 26 2013
12Z RAOBS/LATEST WV IMAGERY AND RUC ANALYSIS SHOW UPR TROF OVER ERN
AMERICA DOWNSTREAM OF MEAN RDG OVER THE W. WNW LLVL FLOW OF H85
TEMPS AS LO AS -18C TO -20C E OF SFC RDG AXIS EXTENDING FM NE MN
INTO WI IS BRINGING MORE LES TO THE FAVORED SN BELTS. INVRN BASE
NEAR H8 AS SHOWN ON THE 12Z APX RAOB HAS SUPPORTED SOME LOCALLY HVY
SHSN OVER THE KEWEENAW AND IN ALGER COUNTY...BUT THE 12Z INL RAOB
CLOSER TO THE INCOMING SFC HI PRES RDG SHOWS A MUCH LOWER INVRN BASE
NEAR H9. SHRWV EMBEDDED IN THE NW FLOW ALF IS DROPPING SEWD THRU MN
THIS AFTN ACCOMPANIED BY BAND OF H7-3 QVECTOR CNVGC THAT IS
IMPACTING UPR MI ON THE CYC SIDE OF THIS FEATURE...BUT THE MID LVLS
ARE SO DRY WITH H85-5 QVECTOR DVGC THESE DYNAMICS APPEAR TO BE
HAVING LTL IMPACT ON THE LES. IN FACT...THE MQT VWP INDICATES THE
SUBSIDENCE INVRN HAS ACTUALLY LOWERED. CLDS ON THE NE EDGE OF THE
DEEPER MSTR ARE BRUSHING THE WI BORDER COUNTIES. BUT VSBL STLT
IMAGERY INDICATES A HEAVIER BAND OF LES PERSISTS OVER NCENTRAL
HOUGHTON COUNTY...WITH VSYBS REPORTED AS LO AS 1/2SM AT CMX. A
HEAVIER SN BAND ALSO IMPACTED ALGER COUNTY NEAR MELSTRAND EARLIER...
BUT THE WINDS HAVE BACKED ENUF TO SHIFT THIS SHSN N THRU ERN ALGER
COUNTY. FARTHER TO THE W...YET ANOTHER SHRTWV IS RIDING THRU BRITISH
COLUMBIA OVER THE WRN RDG.
MAIN FCST CONCERNS IN THE SHORT TERM ARE FOCUSED ON LES TRENDS THRU
THIS EVNG AND GOING HEADLINES.
TNGT...SHRTWV SLIDING SEWD THRU MN IS PROGGED TO REACH THE LOWER GRT
LKS THIS EVNG...LEAVING SHARP DEEP LYR QVECTOR DVGC IN ITS WAKE. IN
RESPONSE TO THE STRONG ACCOMPANYING SUBSIDENCE...INVRN BASES ARE
PROGGED TO FALL AOB 3K FT THRU THE NGT. AS THE SFC HI PRES RDG
SLIDES TO THE SE...THE LLVL FLOW IS PROGGED TO BACK SLOWLY TO THE
WSW BY 12Z FRI. THE COMBINATION OF SINKING INVRN BASE/SHIFTING WINDS
SHOULD DIMINISH THE LES THRU THE NGT...WITH THE LES LINGERING
LONGEST OVER THE N HALF OF THE KEWEENAW AND OVER THE E NEAR LK SUP
FM GRAND MARAIS TOWARD WHITEFISH POINT. OVERALL...GOING HEADLINE
EXPIRATIONS APPEAR ON TRACK...BUT THE EVNG SHIFT MAY BE ABLE TO CANX
THE ALGER/LUCE ADVY EARLY IF INCRSG LAND BREEZE CNVGC DOES NOT
INTENSIFY THE LES NEAR THE SHORE. AS FOR MIN TEMPS...EXPECT THE
LOWEST READINGS OVER THE INTERIOR SCENTRAL...WHERE SKIES WL BE MOCLR
AND WINDS LIGHTER FOR A GOOD PORTION OF THE NGT. A STRONGER S WIND
DVLPG OVER THE WRN ZNS BTWN THE DEPARTING SFC HI AND FALLING MSLP
OVER THE PLAINS AHEAD OF SHRTWV NOW TOPPING THE WRN RDG WL LIMIT THE
DIURNAL FALL THERE DESPITE A PERIOD OF MOCLR-PCLDY SKIES.
FRI...SHRTWV NOW RIDING OVER THE WRN RDG IS PROGGED TO SLIDE ESEWD
THRU ONTARIO/THE UPR LKS ON FRI AFTN...ACCOMPANIED BY A SFC LO
MOVING OVER SRN ONTARIO. WITH SOME FAIRLY SHARP ISENTROPIC ASCENT
SHOWN ON THE 290-295K SFCS /H65-8/...EXPECT INCRSG MID CLDS...
ESPECIALLY OVER THE NE HALF OF THE CWA UNDER THE SHARPER ASCENT.
THESE DYNAMICS/MODEL QPF ALSO SUPPORT GOING CHC POPS OVER THE NE CWA
CLOSER TO THE TRACK OF THE SHRTWV/SFC LO. GIVEN THE INTENSITY OF THE
ISENTROPIC LIFT...SOME H85-7 FGEN...AND THE PERSISTENT CHILL THAT
WOULD SUPPORT BETTER LIFT TO THE SW...SHIFTED THE SW EDGE OF THE
POPS A BIT TO THE SW PER THE SOMEWHAT WETTER GFS/CNDN MODELS. GIVEN
THE HI STABILITY/LLVL COLD AIR...TENDED TOWARD THE LOWER END OF
GUIDANCE FOR MAX TEMPS. EXPECT THE HIEST TEMPS NEAR FRZG OVER THE W
NEAR LK SUP...WHERE STRENGTHENING SSW WIND TO THE S OF PRES FALL
CENTER WL DOWNSLOPE.
.LONG TERM...(FRIDAY NIGHT THROUGH THURSDAY)
ISSUED AT 511 PM EST THU DEC 26 2013
AT THE BEGINNING OF THE LONG TERM...THERE WILL BE A BRIEF WARMUP AS
FLOW TEMPORARILY BECOMES ZONAL ACROSS THE NRN CONUS...ALLOWING
PACIFIC AIR TO SPREAD E. HOWEVER...A REORGANIZING AND EXPANDING
POLAR VORTEX CURRENTLY LOCATED WELL N IN NRN CANADA WILL BE
DEEPENING AS IT DROPS S TO THE VCNTY OF HUDSON BAY OVER THE NEXT 7
DAYS. EARLY NEXT WEEK...A LARGE MASS OF EXTREMELY COLD AIR WILL BE
CENTERED AROUND HUDSON BAY. MEDIUM RANGE MODELS HAVE BEEN FAIRLY
CONSISTENT SHOWING 850MB TEMPS AS LOW AS -35C TO -40C AT THE CORE OF
THE POLAR VORTEX. THE EXPANDING MASS OF ARCTIC AIR WILL SPREAD S
INTO THE GREAT LAKES NEXT WEEK...AND GIVEN THE EXTREME COLD TO THE
N...THERE MAY BE A COUPLE OF SHOTS OF BITTER COLD AIR INTO UPPER MI
DURING THE WEEK. EVOLVING PATTERN WILL NOT BE FAVORABLE FOR MUCH IN
THE WAY OF WIDESPREAD SYNOPTIC SNOWFALL OVER THE NEXT 7 DAYS. AFTER
INITIAL NE-N FLOW MODERATE LAKE EFFECT SNOW EVENT FOR SAT NIGHT INTO
SUNDAY...LES WILL THEN FOCUS OVER THE W TO NW SNOW BELT FOR MUCH OF
NEXT WEEK. LES ON MOST DAYS PROBABLY WON`T BE SIGNIFICANT AS ARCTIC
AIR WILL RESULT IN SMALL SNOWFLAKES. HOWEVER...THE SMALL SNOWFLAKES
WILL BE VERY EFFECTIVE AT REDUCING VISIBILITY. ON THE COLDEST
DAYS...WHITEOUTS WILL PROBABLY BE COMMON WHERE LES OCCURS.
BEGINNING FRI NIGHT...WAA AND 290K ISENTROPIC ASCENT WILL RESULT IN
SOME LINGERING LIGHT SNOW IN THE EVENING OVER MAINLY ERN AND
POSSIBLY OVER THE NW PORTION OF THE CWA BEFORE SNOW ENDS OVERNIGHT
WITH TRANSITION TO ISENTROPIC DESCENT. WILL CONTINUE LOW CHC 30 PCT
POPS FAR EAST WITH SCHC 20 PCT POPS OVER THE KEWEENAW. MIN TEMPS
WILL BE MAINLY IN THE UPPER TEENS TO MID 20S.
WARMER WEATHER WILL CONTINUE INTO SAT AHEAD OF A SHORTWAVE TRACKING
FROM BC/PACIFIC NW INTO THE CANADIAN HIGH PLAINS. MOST LOCATIONS
SHOULD TOP OUT NEAR 30F. HOWEVER...A COLD FRONT DRIFTING S ACROSS
UPPER MI DURING THE DAY SAT WILL HAVE AN INFLUENCE ON MAX TEMPS
DEPENDING ON ITS TIMING. UPPER DIVERGENCE ASSOCIATED WITH THE RIGHT
ENTRANCE OF UPPER JET TO THE N AND NE AND A ZONE OF MIDLEVEL
FRONTOGENESIS WILL SUPPORT A RIBBON OF -SN BEHIND THE SOUTHWARD
SAGGING COLD FRONT. THAT -SN SHOULD SPREAD S ACROSS THE NRN UPPER MI
DURING THE DAY. AS COLD FRONT CONTINUES TO DROP S SAT NIGHT...UPPER
DIVERGENCE/MID LEVEL FRONTOGENESIS AND Q-VECT CONV WILL CONTINUE TO
SUPPORT -SN. SO...EXPECT MOST OF THE FCST AREA TO SEE -SN SAT NIGHT.
LAKE ENHANCEMENT SEEMS LIKELY FOR MOST IF NOT ALL OF NRN UPPER MI
SAT NIGHT INTO SUNDAY AS WINDS SHIFT FROM NE SAT EVENING TO NRLY
LATE SAT NIGHT INTO SUNDAY. MODERATE TO OCCASIONAL HVY SNOW COULD BE
POSSIBLE OVER THE HIGHER TERRAIN OF WEST AND NORTH CENTRAL UPPER MI.
WILL CONTINUE TO HIGHLIGHT THIS SIGNIFICANT SNOW POTENTIAL IN THE
HWO. BEHIND THE FRONT...MUCH COLDER AIR WILL BEGIN TO FLOW S INTO
UPPER MI SAT NIGHT AND ESPECIALLY SUN AS 850MB TEMPS PLUMMET INTO
THE -20 TO -25C RANGE BY SUN AFTERNOON. TEMPS SHOULD SLOWLY FALL
THRU THE DAY ON SUNDAY. EXPECT LINGERING LES INTO SUN NIGHT AND SNOW
COULD BE MODERATE OVER NORTH CENTRAL UPPER MI WITH MODELS INDICATING
PERSISTENT CONVERGENT/CYCLONIC N-NNW FLOW.
PERSISTENT LES WILL THEN SET UP MON/TUE/WED...MOSTLY FOR W TO WNW
WIND FAVORED SNOWBELTS...AS ACRTIC AIR SETTLES OVER THE AREA (850MB
TEMPS GENERALLY IN THE MID TO UPPER -20S C). AT THIS POINT...IT
DOESN`T APPEAR LES ACCUMS WILL BE SIGNIFICANT DUE TO THE ARCTIC AIR
AND CONSEQUENT SMALL SNOWFLAKE SIZE. HOWEVER...IF ANY SHORTWAVES
PROVIDE ENHANCEMENT OR LAND BREEZES FOCUS CONVERGENCE...THERE MAY BE
LOCALLY HVY LES. OTHERWISE...AS PREVIOUSLY MENTIONED...THE SMALL
SNOWFLAKES WILL BE VERY EFFECTIVE AT REDUCING VISIBILITY...SO
WHITEOUTS MAY BE COMMON IN AREAS IMPACTED BY LES EARLY NEXT WEEK.
MAX TEMPS MAY STRUGGLE TO GET ABOVE 0F OVER SOME PORTIONS OF WRN
UPPER MI MON/TUE/WED. MODELS POINTING TOWARD LATE TUE FOR COLDEST
850MB TEMPS ACROSS AREA AROUND -28C. IF SO...SUBZERO HIGH TEMPS
WOULD BE COMMON OVER MUCH OF W AND CNTRL UPPER MI. WIND CHILL VALUES
WILL LIKELY FALL INTO THE ADVY RANGE AT TIMES.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z FRIDAY EVENING)
ISSUED AT 600 PM EST THU DEC 26 2013
CMX...EXPECT MVFR CONDITIONS DURING THE EVNG AS THE LLVL WINDS BACK
TOWARD THE SW AND CAUSE THE HEAVIER LES BANDS TO DRIFT TO THE N. VFR
WX SHOULD THEN DOMINATE ON FRI MRNG WITH A DRIER SW FLOW DESPITE A
GOOD DEAL OF MID CLD COVER.
IWD AND SAW...ALTHOUGH SOME MVFR CIGS MAY IMPACT SAW EARLY THIS
EVENING...EXPECT VFR WX THIS FCST PERIOD WITH A DRY W-SW FLOW TO THE
NW OF HI PRES MOVING TOWARD THE LOWER GRT LKS. WILL GET GUSTY AT
BOTH SITES LATE FRI MORNING INTO EARLY AFTERNOON AT BOTH SITES.
&&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 511 PM EST THU DEC 26 2013
EXPECT WNW WINDS 15 TO 25 KTS LATE THIS AFTERNOON TO DIMINISH WITH
PASSAGE OF SFC HI PRES RDG. BUT THE SHARPENING PRES GRADIENT BETWEEN
THE DEPARTING HI AND ANOTHER LO TRACKING THRU SOUTHERN CANADA WILL
CAUSE SW WINDS TO INCREASE UP TO 25 TO 30 KTS ON FRI. EXPECT BRIEF
LULL IN WINDS LATE FRI NIGHT INTO SAT MORNING AS FRONT DRIFTS S
ACROSS THE AREA. THEN AS ARCTIC AIR FLOWS S INTO THE AREA BEHIND
FRONT...NORTH WINDS TO 30KT WILL BE COMMON SAT NIGHT/SUN...AND THERE
COULD BE A PERIOD OF GALES OVER WEST AND CENTRAL LAKE SUPERIOR.
HVY FREEZING SPRAY WILL ALSO RETURN SAT NIGHT AND WILL LIKELY
CONTINUE THRU THE MIDDLE OF NEXT WEEK AS ARCTIC AIR SETTLES INTO THE
UPPER LAKES FOR AN EXTENDED STAY.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
LAKE EFFECT SNOW ADVISORY UNTIL 1 AM EST FRIDAY FOR MIZ001-006-
007.
LAKE EFFECT SNOW ADVISORY UNTIL 7 PM EST THIS EVENING FOR MIZ002.
LAKE EFFECT SNOW WARNING UNTIL 7 PM EST THIS EVENING FOR MIZ003.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...KC
LONG TERM...VOSS
AVIATION...07
MARINE...KC/VOSS
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
512 PM EST THU DEC 26 2013
.SHORT TERM...(THIS EVENING THROUGH FRIDAY)
ISSUED AT 511 PM EST THU DEC 26 2013
12Z RAOBS/LATEST WV IMAGERY AND RUC ANALYSIS SHOW UPR TROF OVER ERN
AMERICA DOWNSTREAM OF MEAN RDG OVER THE W. WNW LLVL FLOW OF H85
TEMPS AS LO AS -18C TO -20C E OF SFC RDG AXIS EXTENDING FM NE MN
INTO WI IS BRINGING MORE LES TO THE FAVORED SN BELTS. INVRN BASE
NEAR H8 AS SHOWN ON THE 12Z APX RAOB HAS SUPPORTED SOME LOCALLY HVY
SHSN OVER THE KEWEENAW AND IN ALGER COUNTY...BUT THE 12Z INL RAOB
CLOSER TO THE INCOMING SFC HI PRES RDG SHOWS A MUCH LOWER INVRN BASE
NEAR H9. SHRWV EMBEDDED IN THE NW FLOW ALF IS DROPPING SEWD THRU MN
THIS AFTN ACCOMPANIED BY BAND OF H7-3 QVECTOR CNVGC THAT IS
IMPACTING UPR MI ON THE CYC SIDE OF THIS FEATURE...BUT THE MID LVLS
ARE SO DRY WITH H85-5 QVECTOR DVGC THESE DYNAMICS APPEAR TO BE
HAVING LTL IMPACT ON THE LES. IN FACT...THE MQT VWP INDICATES THE
SUBSIDENCE INVRN HAS ACTUALLY LOWERED. CLDS ON THE NE EDGE OF THE
DEEPER MSTR ARE BRUSHING THE WI BORDER COUNTIES. BUT VSBL STLT
IMAGERY INDICATES A HEAVIER BAND OF LES PERSISTS OVER NCENTRAL
HOUGHTON COUNTY...WITH VSYBS REPORTED AS LO AS 1/2SM AT CMX. A
HEAVIER SN BAND ALSO IMPACTED ALGER COUNTY NEAR MELSTRAND EARLIER...
BUT THE WINDS HAVE BACKED ENUF TO SHIFT THIS SHSN N THRU ERN ALGER
COUNTY. FARTHER TO THE W...YET ANOTHER SHRTWV IS RIDING THRU BRITISH
COLUMBIA OVER THE WRN RDG.
MAIN FCST CONCERNS IN THE SHORT TERM ARE FOCUSED ON LES TRENDS THRU
THIS EVNG AND GOING HEADLINES.
TNGT...SHRTWV SLIDING SEWD THRU MN IS PROGGED TO REACH THE LOWER GRT
LKS THIS EVNG...LEAVING SHARP DEEP LYR QVECTOR DVGC IN ITS WAKE. IN
RESPONSE TO THE STRONG ACCOMPANYING SUBSIDENCE...INVRN BASES ARE
PROGGED TO FALL AOB 3K FT THRU THE NGT. AS THE SFC HI PRES RDG
SLIDES TO THE SE...THE LLVL FLOW IS PROGGED TO BACK SLOWLY TO THE
WSW BY 12Z FRI. THE COMBINATION OF SINKING INVRN BASE/SHIFTING WINDS
SHOULD DIMINISH THE LES THRU THE NGT...WITH THE LES LINGERING
LONGEST OVER THE N HALF OF THE KEWEENAW AND OVER THE E NEAR LK SUP
FM GRAND MARAIS TOWARD WHITEFISH POINT. OVERALL...GOING HEADLINE
EXPIRATIONS APPEAR ON TRACK...BUT THE EVNG SHIFT MAY BE ABLE TO CANX
THE ALGER/LUCE ADVY EARLY IF INCRSG LAND BREEZE CNVGC DOES NOT
INTENSIFY THE LES NEAR THE SHORE. AS FOR MIN TEMPS...EXPECT THE
LOWEST READINGS OVER THE INTERIOR SCENTRAL...WHERE SKIES WL BE MOCLR
AND WINDS LIGHTER FOR A GOOD PORTION OF THE NGT. A STRONGER S WIND
DVLPG OVER THE WRN ZNS BTWN THE DEPARTING SFC HI AND FALLING MSLP
OVER THE PLAINS AHEAD OF SHRTWV NOW TOPPING THE WRN RDG WL LIMIT THE
DIURNAL FALL THERE DESPITE A PERIOD OF MOCLR-PCLDY SKIES.
FRI...SHRTWV NOW RIDING OVER THE WRN RDG IS PROGGED TO SLIDE ESEWD
THRU ONTARIO/THE UPR LKS ON FRI AFTN...ACCOMPANIED BY A SFC LO
MOVING OVER SRN ONTARIO. WITH SOME FAIRLY SHARP ISENTROPIC ASCENT
SHOWN ON THE 290-295K SFCS /H65-8/...EXPECT INCRSG MID CLDS...
ESPECIALLY OVER THE NE HALF OF THE CWA UNDER THE SHARPER ASCENT.
THESE DYNAMICS/MODEL QPF ALSO SUPPORT GOING CHC POPS OVER THE NE CWA
CLOSER TO THE TRACK OF THE SHRTWV/SFC LO. GIVEN THE INTENSITY OF THE
ISENTROPIC LIFT...SOME H85-7 FGEN...AND THE PERSISTENT CHILL THAT
WOULD SUPPORT BETTER LIFT TO THE SW...SHIFTED THE SW EDGE OF THE
POPS A BIT TO THE SW PER THE SOMEWHAT WETTER GFS/CNDN MODELS. GIVEN
THE HI STABILITY/LLVL COLD AIR...TENDED TOWARD THE LOWER END OF
GUIDANCE FOR MAX TEMPS. EXPECT THE HIEST TEMPS NEAR FRZG OVER THE W
NEAR LK SUP...WHERE STRENGTHENING SSW WIND TO THE S OF PRES FALL
CENTER WL DOWNSLOPE.
.LONG TERM...(FRIDAY NIGHT THROUGH THURSDAY)
ISSUED AT 511 PM EST THU DEC 26 2013
AT THE BEGINNING OF THE LONG TERM...THERE WILL BE A BRIEF WARMUP AS
FLOW TEMPORARILY BECOMES ZONAL ACROSS THE NRN CONUS...ALLOWING
PACIFIC AIR TO SPREAD E. HOWEVER...A REORGANIZING AND EXPANDING
POLAR VORTEX CURRENTLY LOCATED WELL N IN NRN CANADA WILL BE
DEEPENING AS IT DROPS S TO THE VCNTY OF HUDSON BAY OVER THE NEXT 7
DAYS. EARLY NEXT WEEK...A LARGE MASS OF EXTREMELY COLD AIR WILL BE
CENTERED AROUND HUDSON BAY. MEDIUM RANGE MODELS HAVE BEEN FAIRLY
CONSISTENT SHOWING 850MB TEMPS AS LOW AS -35C TO -40C AT THE CORE OF
THE POLAR VORTEX. THE EXPANDING MASS OF ARCTIC AIR WILL SPREAD S
INTO THE GREAT LAKES NEXT WEEK...AND GIVEN THE EXTREME COLD TO THE
N...THERE MAY BE A COUPLE OF SHOTS OF BITTER COLD AIR INTO UPPER MI
DURING THE WEEK. EVOLVING PATTERN WILL NOT BE FAVORABLE FOR MUCH IN
THE WAY OF WIDESPREAD SYNOPTIC SNOWFALL OVER THE NEXT 7 DAYS. AFTER
INITIAL NE-N FLOW MODERATE LAKE EFFECT SNOW EVENT FOR SAT NIGHT INTO
SUNDAY...LES WILL THEN FOCUS OVER THE W TO NW SNOW BELT FOR MUCH OF
NEXT WEEK. LES ON MOST DAYS PROBABLY WON`T BE SIGNIFICANT AS ARCTIC
AIR WILL RESULT IN SMALL SNOWFLAKES. HOWEVER...THE SMALL SNOWFLAKES
WILL BE VERY EFFECTIVE AT REDUCING VISIBILITY. ON THE COLDEST
DAYS...WHITEOUTS WILL PROBABLY BE COMMON WHERE LES OCCURS.
BEGINNING FRI NIGHT...WAA AND 290K ISENTROPIC ASCENT WILL RESULT IN
SOME LINGERING LIGHT SNOW IN THE EVENING OVER MAINLY ERN AND
POSSIBLY OVER THE NW PORTION OF THE CWA BEFORE SNOW ENDS OVERNIGHT
WITH TRANSITION TO ISENTROPIC DESCENT. WILL CONTINUE LOW CHC 30 PCT
POPS FAR EAST WITH SCHC 20 PCT POPS OVER THE KEWEENAW. MIN TEMPS
WILL BE MAINLY IN THE UPPER TEENS TO MID 20S.
WARMER WEATHER WILL CONTINUE INTO SAT AHEAD OF A SHORTWAVE TRACKING
FROM BC/PACIFIC NW INTO THE CANADIAN HIGH PLAINS. MOST LOCATIONS
SHOULD TOP OUT NEAR 30F. HOWEVER...A COLD FRONT DRIFTING S ACROSS
UPPER MI DURING THE DAY SAT WILL HAVE AN INFLUENCE ON MAX TEMPS
DEPENDING ON ITS TIMING. UPPER DIVERGENCE ASSOCIATED WITH THE RIGHT
ENTRANCE OF UPPER JET TO THE N AND NE AND A ZONE OF MIDLEVEL
FRONTOGENESIS WILL SUPPORT A RIBBON OF -SN BEHIND THE SOUTHWARD
SAGGING COLD FRONT. THAT -SN SHOULD SPREAD S ACROSS THE NRN UPPER MI
DURING THE DAY. AS COLD FRONT CONTINUES TO DROP S SAT NIGHT...UPPER
DIVERGENCE/MID LEVEL FRONTOGENESIS AND Q-VECT CONV WILL CONTINUE TO
SUPPORT -SN. SO...EXPECT MOST OF THE FCST AREA TO SEE -SN SAT NIGHT.
LAKE ENHANCEMENT SEEMS LIKELY FOR MOST IF NOT ALL OF NRN UPPER MI
SAT NIGHT INTO SUNDAY AS WINDS SHIFT FROM NE SAT EVENING TO NRLY
LATE SAT NIGHT INTO SUNDAY. MODERATE TO OCCASIONAL HVY SNOW COULD BE
POSSIBLE OVER THE HIGHER TERRAIN OF WEST AND NORTH CENTRAL UPPER MI.
WILL CONTINUE TO HIGHLIGHT THIS SIGNIFICANT SNOW POTENTIAL IN THE
HWO. BEHIND THE FRONT...MUCH COLDER AIR WILL BEGIN TO FLOW S INTO
UPPER MI SAT NIGHT AND ESPECIALLY SUN AS 850MB TEMPS PLUMMET INTO
THE -20 TO -25C RANGE BY SUN AFTERNOON. TEMPS SHOULD SLOWLY FALL
THRU THE DAY ON SUNDAY. EXPECT LINGERING LES INTO SUN NIGHT AND SNOW
COULD BE MODERATE OVER NORTH CENTRAL UPPER MI WITH MODELS INDICATING
PERSISTENT CONVERGENT/CYCLONIC N-NNW FLOW.
PERSISTENT LES WILL THEN SET UP MON/TUE/WED...MOSTLY FOR W TO WNW
WIND FAVORED SNOWBELTS...AS ACRTIC AIR SETTLES OVER THE AREA (850MB
TEMPS GENERALLY IN THE MID TO UPPER -20S C). AT THIS POINT...IT
DOESN`T APPEAR LES ACCUMS WILL BE SIGNIFICANT DUE TO THE ARCTIC AIR
AND CONSEQUENT SMALL SNOWFLAKE SIZE. HOWEVER...IF ANY SHORTWAVES
PROVIDE ENHANCEMENT OR LAND BREEZES FOCUS CONVERGENCE...THERE MAY BE
LOCALLY HVY LES. OTHERWISE...AS PREVIOUSLY MENTIONED...THE SMALL
SNOWFLAKES WILL BE VERY EFFECTIVE AT REDUCING VISIBILITY...SO
WHITEOUTS MAY BE COMMON IN AREAS IMPACTED BY LES EARLY NEXT WEEK.
MAX TEMPS MAY STRUGGLE TO GET ABOVE 0F OVER SOME PORTIONS OF WRN
UPPER MI MON/TUE/WED. MODELS POINTING TOWARD LATE TUE FOR COLDEST
850MB TEMPS ACROSS AREA AROUND -28C. IF SO...SUBZERO HIGH TEMPS
WOULD BE COMMON OVER MUCH OF W AND CNTRL UPPER MI. WIND CHILL VALUES
WILL LIKELY FALL INTO THE ADVY RANGE AT TIMES.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z FRIDAY AFTERNOON)
ISSUED AT 1220 PM EST THU DEC 26 2013
CMX...EXPECT IFR CONDITIONS TO PREDOMINATE INTO THIS EVNG UNDER SOME
HEAVIER LES BANDS. VSBYS INTO MID AFTN WL FALL TO LIFR AT TIMES
UNDER A HEAVY BAND SHOWN ON VSBL STLT IMAGERY. CONDITIONS WL THEN
IMPROVE TO MVFR DURING THE EVNG AS THE LLVL WINDS BACK TOWARD THE SW
AND CAUSE THE HEAVIER LES BANDS TO DRIFT TO THE N. VFR WX SHOULD
THEN DOMINATE ON FRI MRNG WITH A DRIER SW FLOW DESPITE A GOOD DEAL
OF MID CLD COVER.
IWD AND SAW...ALTHOUGH SOME MVFR CIGS MAY IMPACT SAW AT TIMES THIS
AFTN...EXPECT VFR WX THIS FCST PERIOD WITH A DRY W-SW FLOW TO THE NW
OF HI PRES MOVING TOWARD THE LOWER GRT LKS.
&&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 511 PM EST THU DEC 26 2013
EXPECT WNW WINDS 15 TO 25 KTS LATE THIS AFTERNOON TO DIMINISH WITH
PASSAGE OF SFC HI PRES RDG. BUT THE SHARPENING PRES GRADIENT BETWEEN
THE DEPARTING HI AND ANOTHER LO TRACKING THRU SOUTHERN CANADA WILL
CAUSE SW WINDS TO INCREASE UP TO 25 TO 30 KTS ON FRI. EXPECT BRIEF
LULL IN WINDS LATE FRI NIGHT INTO SAT MORNING AS FRONT DRIFTS S
ACROSS THE AREA. THEN AS ARCTIC AIR FLOWS S INTO THE AREA BEHIND
FRONT...NORTH WINDS TO 30KT WILL BE COMMON SAT NIGHT/SUN...AND THERE
COULD BE A PERIOD OF GALES OVER WEST AND CENTRAL LAKE SUPERIOR.
HVY FREEZING SPRAY WILL ALSO RETURN SAT NIGHT AND WILL LIKELY
CONTINUE THRU THE MIDDLE OF NEXT WEEK AS ARCTIC AIR SETTLES INTO THE
UPPER LAKES FOR AN EXTENDED STAY.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
LAKE EFFECT SNOW ADVISORY UNTIL 1 AM EST FRIDAY FOR MIZ001-006-
007.
LAKE EFFECT SNOW ADVISORY UNTIL 7 PM EST THIS EVENING FOR MIZ002.
LAKE EFFECT SNOW WARNING UNTIL 7 PM EST THIS EVENING FOR MIZ003.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...KC
LONG TERM...VOSS
AVIATION...KC
MARINE...KC/VOSS
AREA FORECAST DISCUSSION...UPDATED
NWS TWIN CITIES/CHANHASSEN MN
1213 PM CST THU DEC 26 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 348 AM CST THU DEC 26 2013
WE CONTINUE TO FIND OURSELVES WITHIN MOIST CYCLONIC NORTHWEST FLOW
THIS MORNING...WITH CLOUDS AND BOUTS OF FLURRIES/LIGHT SNOW
CONTINUING TO DOMINATE THE NRN PLAINS AND UPPER MS VALLEY. THE TWO
FEATURES OF INTEREST THIS MORNING ARE THE STRONG UPPER WAVE
CURRENTLY VISIBLE IN WATER VAPOR IMAGERY MOVING ACROSS THE DAKOTAS
AND A WARM/STATIONARY FRONT THAT IS MORE OR LESS LINED UP WITH THE
MN RIVER FROM WC INTO SE MN. CURRENT THINKING IS THAT THIS FRONT
WILL ACT AS A FOCUS FOR A HEAVIER BAND OF PRECIP FROM ABOUT 15Z-21Z
TODAY. BASED POP/QPF GRIDS FOR THIS BAND OF SNOW ON THE GFS AND
SREF...WHICH RESULTED IN THE BAND COMING DOWN BETWEEN I-94 AND THE
MN RIVER. THOUGH CATEGORICAL POPS HAVE BEEN RETAINED...THE HRRR AND
HOPWRF MEMBERS ALONG THE THE NAM/GEM SHOW VERY LITTLE SNOW COMING
DOWN ALONG THIS FRONT...INSTEAD TAKING MOST OF IT ACROSS NRN MN WITH
THE BRUNT OF THE FORCING WITH THE UPPER WAVE...SO WOULD NOT BE
SURPRISED IF THESE POPS END UP BEING OVERDONE. THIS LOOKS TO BE A
FAIRLY TRANSIENT FEATURE WHICH MEANS IT IS ONLY EXPECTED TO BRING A
DUSTING TO ONE INCH OF SNOW. FOR THIS AFTERNOON INTO TONIGHT...WE
FINALLY GET ON THE BACKSIDE OF ALL OF THE PASSING SHORTWAVES IN NW
FLOW...WHICH MEANS WE WILL FINALLY SHUT OFF THE SNOW MACHINES AND
WORK A CLEARING OF THE LOW CLOUDS AT LEAST FROM WEST TO EAST.
FOR TEMPERATURES...BASED ON THE WARMER TEMPERATES SEEN
YESTERDAY...FAVORED HIGHS TODAY TOWARD THE HIGHER END OF
GUIDANCE...ESPECIALLY SOUTH OF THE BOUNDARY. FOR TONIGHT...WINDS
WILL START TO INCREASE OUT OF THE SW AND WILL START TO ADVECT IN A
MILDER PACIFIC AIRMASS. THE WAA WILL BE TEMPERED A BIT BY AT LEAST A
PARTIAL CLEARING OF THE SKIES AND ATTENDANT RADIATIONAL
COOLING...BUT LOOKS TO BE ENOUGH TO SAFELY KEEP EVERYONE ABOVE ZERO
FOR A SECOND NIGHT IN A ROW.
.LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 348 AM CST THU DEC 26 2013
LONG TERM TRENDS CONTINUE TO REMAIN ON TRACK AT LEAST EARLY IN THE
PERIOD. STILL SEE THE POTENTIAL OF AT LEAST GROUND BLIZZARD
CONDITIONS DEVELOPING BY SATURDAY NIGHT ACROSS MUCH OF WESTERN
INTO SOUTHERN MINNESOTA. STILL RATHER MILD BEFORE THEN.
SHOULD SEE SOME HIGH TEMPERATURES WARMING TO AROUND 40 OR SO IN
SOUTHWEST MINNESOTA ON FRIDAY. VERY MILD PACIFIC AIR RIDES EAST
INTO THE AREA FRIDAY...WITH 85H TEMPERATURES WARMING TO 8-10C BY
FRIDAY EVENING OVER THE SOUTHWEST. MINIMAL MIX WITH THIS SHOULD
YIELD THE WARMER TEMPERATURES...WITH LOWER AND SOME MIDDLE 30S TO
THE EAST. SHOULD REMAIN RATHER WARM FRIDAY NIGHT AHEAD OF THE
ARCTIC FRONT. LOWS WILL BE DETERMINED BY WINDS OVERNIGHT. ANY
DECOUPLING OF THE BL WILL STILL GENERATE SOME COOL READINGS.
OVERALL...MODELS HAVE TRENDED A LITTLE WETTER WITH THE TROUGH ASSOCIATED
WITH THE ARCTIC COLD FRONT THAT WILL DIVE SOUTH OVER THE AREA
SATURDAY NIGHT. IT DOES APPEAR THERE WILL BE THE POTENTIAL OF AT
LEAST A PERIOD OF SNOW ASSOCIATED WITH THIS FEATURE AS IT MOVES
THROUGH. DID USE POTWX AND INTRODUCED SOME FREEZING DRIZZLE AT
LEAST INITIALLY AS THE FRONT ARRIVES. THIS...ALONG WITH SOME OF
THE MORE MILD TEMPERATURES MAY PROHIBIT SIGNIFICANT BLOWING SNOW
DEVELOPMENT FOR A TIME...BUT BELIEVE ANY POTENTIAL CRUST ON THE
SNOW WILL BE ERODED BY THE STRONG WINDS DEVELOPING AS THE COLD AIR
ARRIVES. BUFKIT PROFILES STILL INDICATE WIND GUSTS AROUND 35 KTS PLUS
LIKELY SATURDAY NIGHT...ESPECIALLY ALONG AND SOUTH OF THE
MINNESOTA RIVER VALLEY. THIS SHOULD BE ENOUGH TO GENERATE THE MORE
WIDESPREAD BLOWING SNOW CONDITIONS. WILL HAVE TO MONITOR THIS
TREND WITH HEADLINES A DEFINITE POSSIBILITY.
VERY COLD CONDITIONS ENSUE FOR MONDAY AND TUESDAY. MONDAY MORNING
APPEARS TO BE LIKELY THE COLDEST FOR THE CWA...WITH TUESDAY
MORNING A GOOD SECOND...ESPECIALLY TO THE EAST. MUCH OF THE AREA
MAY STAY BELOW ZERO ON MONDAY. SURFACE WINDS SHOULD BE
LIGHT...BUT MAY STILL PRODUCE WIND CHILLS CLOSE TO WARNING
CRITERIA OVER THE NORTHERN CWA SUNDAY NIGHT/MONDAY MORNING. TIMING
OF ANY ADDITIONAL SNOW EVENTS DIFFICULT...ALTHOUGH THE GFS AND GEM
CONTINUE TO TRACK A SHOT OF LIGHT SNOW OVER SOUTHERN MINNESOTA
MONDAY NIGHT INTO EARLY TUESDAY. HAVE ENTERED A CHANCE FOR SNOW
WITH THIS FOR NOW. SOME MINOR TEMPERATURE MODERATION LATER IN THE
PERIOD COULD YIELD MORE LIGHT SNOW...BUT DIFFICULT TO LATCH ONTO
ANYTHING SIGNIFICANT AT THIS TIME.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z FRIDAY AFTERNOON)
ISSUED AT 1149 AM CST THU DEC 26 2013
SNOW WILL CONTINUE SLIDING SOUTHEAST ACROSS ERN MN AND SWRN MN
EARLY THIS AFTERNOON WITH DRY CONDITIONS THEREAFTER. VSBYS HAVE
IMPROVING WITH THE SNOW AND INTENSITY SHOULD CONTINUE TO WANE IN
THE NEXT COUPLE HOURS. MVFR CIGS LIKELY TO REMAIN INTO THIS
EVENING NORTH OF THE MN RIVER...BUT IMPROVING CONDITIONS EXPECTED
LATE TONIGHT AND ESPECIALLY FRIDAY.
KMSP...SNOW SHOULD END BY 20Z...OTHERWISE CIGS WILL BOUNCE BACK
AND FORTH BETWEEN VFR/MVFR THROUGH THE EVENING /REMAINING ABOVE 017./
VFR RETURNS LATE TONIGHT AND FRIDAY.
/OUTLOOK FOR KMSP/
FRI NIGHT...VFR. WINDS SW 4-8 KTS.
SAT...VFR. CHC MVFR/-SN LATE. LIGHT/VAR WINDS BCMG N 20G30KTS LATE.
SUN...VFR. WINDS NW 10 KTS.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
&&
$$
SHORT TERM...MPG
LONG TERM...DWE
AVIATION...BORGHOFF
AREA FORECAST DISCUSSION
NWS HASTINGS NE
1215 PM CST THU DEC 26 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 500 AM CST THU DEC 26 2013
WITH A CONTINUED EFFECTIVELY ZERO RISK OF PRECIP DURING THE NEXT
24 HOURS...TEMPS/SKY COVER/WIND SPEEDS REMAIN THE MAIN ISSUES. AS
DESCRIBED IN DETAIL BELOW...BOTH WIND SPEEDS AND ESPECIALLY TEMPS
HAVE BEEN BUMPED UP FOR TODAY...WITH THE MAIN WILD CARD FACTOR
BEING THE EXTENT/DURATION OF INCOMING MID-HIGH LEVEL CLOUDS.
ALTHOUGH MODELS SUCH AS THE NAM AND TO A MUCH LESSER EXTENT THE
RAP CONTINUE TO STRUGGLE WITH POORLY INITIALIZED/OVERDONE SNOW
COVER FIELDS...THE VERY LATEST 06Z NAM HAS FINALLY STARTED
LATCHING ONTO REALITY AND HOPEFULLY HELPS PAVE THE WAY FOR MORE
STRAIGHTFORWARD TEMP FORECASTING OVER THE NEXT FEW DAYS.
STARTING OFF EARLY THIS MORNING AS OF 0930Z THE LATEST 11-3.9
MICRON SATELLITE LOOP REVEALED PREDOMINANTLY CLEAR SKIES OVER THE
CWA...ALTHOUGH A FAIRLY DECENT BATCH OF MID-HIGH CLOUDS WAS
STEADILY APPROACHING THE AREA FROM SD. WATER VAPOR SATELLITE
IMAGERY AND SHORT TERM MODEL DATA DEPICTED CONTINUED NORTHWEST
MID-UPPER LEVEL FLOW OVER THE CENTRAL PLAINS...FLOWING BETWEEN A
LARGE SCALE TROUGH OVER THE EASTERN CONUS AND AN EXPANSIVE RIDGE
CENTERED ALONG/WEST OF THE PACIFIC COAST. ON THE SMALLER SCALE...A
FAIRLY SUBTLE DISTURBANCE WAS MAKING ITS WAY SOUTH-SOUTHEAST
ACROSS THE DAKOTAS AND IS LARGELY RESPONSIBLE FOR THE INCOMING
CLOUDS...WITH THIS FEATURE LOCATED WITHIN THE LEFT EXIT REGION OF
THE LATEST IN A SERIES OF 110+KT UPPER JET STREAKS POKING
SOUTHWARD INTO THE NORTHERN ROCKIES OUT OF SOUTHWESTERN CANADA. AT
THE SURFACE...09Z OBJECTIVE ANALYSIS AND AREA AUTOMATED OBS
REVEALED THE PRESENCE OF A SUBTLE NORTH-SOUTH TROUGH AXIS ACROSS
THE CWA...EXTENDING SOUTHWARD FROM A 1014 MILLIBAR LOW CENTERED
NEAR THE BORDER OF ND/SASKATCHEWAN/MANITOBA. MEANWHILE TO THE
SOUTH...A BROAD 1031MB HIGH WAS CENTERED OVER THE OK/WEST TX AREA.
THE NET RESULT OF THESE FEATURES IS A GENERALLY SOUTHWESTERLY
BREEZE OF 5-10 MPH ACROSS MOST OF THE CWA WITH SOME HIGHER GUSTS.
AS IS TYPICAL...THERE HAS BEEN AN EBB AND FLOW OF TEMPS OVERNIGHT
ACROSS THE CWA...AS THE FACTORS OF CLEAR SKIES AND LOCALIZED VERY
LIGHT BREEZES HAVE ALLOWED SOME PLACES TO FALL FAIRLY
EFFICIENTLY...WHILE OTHER PLACES INCLUDING THE TRI-CITIES HAVE
BEEN HELD UP FAIRLY WELL BY THE WESTERLY BREEZES. ALTHOUGH THESE
FLUCTUATIONS WILL CONTINUE THROUGH DAYBREAK...THE GENERAL
EXPECTATION IS THAT OVERNIGHT LOW TEMPERATURES ACROSS THE MAJORITY
OF THE CWA HAVE SETTLED/WILL SETTLE SOMEWHERE INTO THE 17-24 RANGE.
GETTING INTO THE DAYTIME FORECAST...THE BIG PICTURE ALOFT IN THE
MID-UPPER LEVELS INVOLVES THE CONTINUATION OF VERY SUBTLE HEIGHT
RISES AS EVIDENT AT 500MB...AS THE DISTURBANCE CURRENTLY CENTERED
OVER THE DAKOTAS TRACKS SOUTHEAST OVER MAINLY EASTERN PORTIONS OF
THE LOCAL AREA...BUT ESPECIALLY INTO THE IA/MN AREA...ALLOWING THE
WESTERN RIDGE TO NUDGE EVER SO SLIGHTLY EAST INTO THE CENTRAL PLAINS.
AS THIS OCCURS...THE TRAILING NORTH-SOUTH ORIENTED UPPER JET
STREAK WILL ALSO SLIDE EAST FROM THE NORTHERN ROCKIES INTO THE
DAKOTAS OVER THE COURSE OF THE DAY. AT THE SURFACE TODAY...THERE
WILL BE A SIMILAR SCENARIO TO WHAT OCCURRED YESTERDAY...AS
INITIALLY SOUTHWESTERLY BREEZES WILL SWITCH TO NORTHWESTERLY IN
RESPONSE TO THE EASTWARD PROGRESSION OF THE PARENT SURFACE TROUGH
CENTERED TO THE NORTH. AS MIXING HEIGHTS INCREASE TO THE 900-875MB
RANGE PER RAP SOUNDINGS...WIND SPEEDS WILL PICK UP WITH SUSTAINED
NORTHWESTERLY SPEEDS OF 15-20 MPH AND GUSTS UP TO AROUND 25
MPH...WITH THE MAIN TIME FRAME OF STRONGEST BREEZES CENTERED
BETWEEN LATE MORNING AND MID-AFTERNOON BEFORE SUBSIDING AGAIN
LATER IN THE AFTERNOON. THESE WIND SPEEDS REFLECT ROUGHLY A 5 MPH
INCREASE VERSUS PREVIOUS FORECAST FOR MUCH OF THE AREA. TURNING TO
SKY COVER...THIS IS A BIT OF A QUESTION MARK TODAY AS MODELS ARE
HANDLING THE INCOMING CLOUD DECK SOMEWHAT DIFFERENTLY. THE GENERAL
EXPECTATION THOUGH IS THAT ALTHOUGH ESPECIALLY NORTHERN PARTS OF
THE AREA COULD GO MOSTLY CLOUDY FOR A TIME THIS MORNING...THE
OVERALL DENSITY OF THIS CLOUD DECK SHOULD FADE WITH TIME AND WITH
SOUTHWARD EXTENT...RESULTING IN NO WORSE THAN PARTLY CLOUDY IF NOT
MOSTLY SUNNY CONDITIONS THROUGH THE BALANCE OF THE DAY. PUT
ANOTHER WAY...THE CURRENT SKY COVER GRIDS MAY NOT BE QUITE
AGGRESSIVE ENOUGH FOR LATER THIS MORNING...BUT THINK THAT THE DAY
OVERALL WILL FEATURE MORE SUN THAN CLOUDS. AS FOR TEMPS TODAY...FOR
NOW WILL ASSUME A RATHER NEGLIGIBLE EFFECT OF PASSING CLOUD
COVER...AND THUS GIVEN THE DECENT LOW LEVEL MIXING REGIME IN
PLACE...HAVE BOOSTED HIGH TEMPS AT LEAST A FEW DEGREES VERSUS
PREVIOUS FORECAST ACROSS THE NORTHERN HALF OF THE CWA...AND AS
MUCH AS 5-9 DEGREES IN THE SOUTH. BASED ON WHAT HAPPENED
YESTERDAY...NEARLY ALL PRIMARY MODELS/GUIDANCE FELL AT LEAST
SLIGHTLY SHORT OF ACTUAL HIGHS...BUT HOURLY RAP13 TEMPS ENDED UP
BEING ONE OF THE BEST SOLUTIONS. AS A RESULT...HAVE AGAIN OPTED TO
FOLLOW RAP13 TEMPS QUITE CLOSELY TODAY...WHICH RESULTS IN HIGHS
GENERALLY 4-7 DEGREE WARMER THAN A SIMPLE BLEND OF 00Z MET/MAV
GUIDANCE. THE NET RESULT IS HIGH TEMPERATURES AIMED FROM THE UPPER
40S/LOW 50S IN THE NORTHERN 1/2 OF THE CWA TO PREDOMINANTLY MID-
50S IN KS ZONES. IF ANYTHING...MIGHT NOT HAVE GONE WARM ENOUGH IN
NORTHEAST ZONES. THIS INCREASE IN HIGH TEMPS RESULTS IN AFTERNOON
RELATIVE HUMIDITY VALUES FORECAST TO DROP AROUND 25 PERCENT OR
SLIGHTLY LOWER IN SOUTHWESTERN COUNTIES...BUT GIVEN THAT SUSTAINED
WINDS SHOULD AVERAGE CLOSER TO 15 MPH THAN 20 MPH IN THESE
AREAS...THE SETUP APPEARS TO FALL A BIT SHORT OF JUSTIFYING A
NEAR-CRITICAL FIRE DANGER MENTION IN THE HAZARDOUS WEATHER
OUTLOOK.
TURNING TO THIS EVENING/TONIGHT...THE LARGE SCALE SYNOPTIC PICTURE
INVOLVES THE CONTINUED EXPANSION OF THE WESTERN CONUS RIDGE
EASTWARD OVER THE CENTRAL PLAINS...ACCOMPANIED BY RESULTANT MID-
LEVEL HEIGHT RISES. ALTHOUGH THE PRIMARY UPPER JET CORE WILL
CONTINUE TO SLIDE OFF TO THE NORTH-NORTHEAST OF THE AREA...THE
CONTINUED NORTH-NORTHWESTERLY FLOW ALOFT OVER THE CENTRAL PLAINS
WILL NONETHELESS FEATURE THE PASSAGE OF AT LEAST ONE SUBTLE...LOW-
AMPLITUDE SHORTWAVE TROUGH DURING THE NIGHT. ALTHOUGH THIS COULD
EASILY RESULT IN A MODEST INCREASE IN MID-HIGH LEVEL CLOUDS MAINLY
AFTER MIDNIGHT AND MAINLY IN NORTHERN ZONES...THE NIGHT AS A WHOLE
SHOULD AVERAGE NO WORSE THAN MOSTLY CLEAR ACROSS THE ENTIRE CWA.
AT THE SURFACE TONIGHT...A NOW-FAMILIAR PATTERN WILL AGAIN REPEAT
ITSELF...AS A SUBTLE TROUGH AXIS WILL AGAIN EXTEND SOUTHWARD INTO
THE CENTRAL PLAINS FROM A PARENT LOW PRESSURE SYSTEM CENTERED WELL
TO THE NORTH OVER SOUTH CENTRAL CANADA. THIS WILL AGAIN TRANSITION
THE NORTHWESTERLY BREEZES OF THIS AFTERNOON TO FAIRLY LIGHT
WESTERLY BREEZES THIS EVENING...AND THEN 5-10 MPH SOUTHWESTERLY
BREEZES AFTER MIDNIGHT. WITH THE SKY COVER...WIND SPEED/DIRECTION
AND LOW LEVEL THERMAL PROFILES TONIGHT SETTING UP TO BE QUITE
SIMILAR TO THOSE OF THIS MORNING...SEE NO REASON WHY TEMPERATURE
BEHAVIOR WON/T BE SIMILAR AS WELL...WITH PLENTY OF HOUR-TO-HOUR
AND SMALL-SCALE VARIABILITY. ALTHOUGH VERY LITTLE CHANGE WAS MADE
TO LOWS FROM THE PREVIOUS FORECAST...STILL CALLING FOR NEARLY THE
ENTIRE CWA TO SETTLE WITHIN A FEW DEGREES EITHER SIDE OF 20 AT
SOME POINT IN THE NIGHT...THIS IS STILL A FEW DEGREES ABOVE A
STRAIGHT-UP 00Z MET/MAV GUIDANCE BLEND...AND WOULD NOT BE
SURPRISED IF THE NEXT SHIFT CONSIDERS RAISING LOWS A BIT MORE IN
SOME PLACES.
.LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 500 AM CST THU DEC 26 2013
THE BIGGEST CHALLENGE WILL BE DETERMINING THE TIMING OF A COLD FRONT
SATURDAY...WHICH WILL SUBSEQUENTLY AFFECT HIGH TEMPERATURES ON
SATURDAY AND WIND SPEEDS SATURDAY/SATURDAY NIGHT.
WE BEGIN THE LONG TERM FORECAST IN A TRANSITION OF SORTS. THE RIDGE
OVER THE WESTERN UNITED STATES WILL DEAMPLIFY AS IT MOVES
EAST...BEING BROKEN DOWN BY AN APPROACHING SHORTWAVE TROUGH ENTERING
THE COAST OF THE PACIFIC NORTHWEST BY LATE DAY FRIDAY. WE WILL
CLEARLY BE IN THE WARM SECTOR WITH HIGHS EASILY REACHING THE 50S FOR
MOST LOCATIONS IF NOT 60 FOR MUCH OF NORTH CENTRAL KANSAS. MODEL
OUTPUT IS NOT OPTIMAL FOR MAXIMUM TEMPERATURE FORECASTS AS A PHANTOM
SNOWPACK LINGERS OVER MUCH OF THE AREA AND IS DISTURBING THE MODEL
SOLUTIONS...ESPECIALLY FOR MAX T AND WIND FIELDS. REALLY HAD TO LEAN
ON ENSEMBLE DATA AND OPERATIONAL MODELS SUCH AS THE ECMWF THAT
EITHER DO NOT INCLUDE SNOWPACK...OR HAVE LIMITED SNOWPACK DATA
ENTERED INTO MODEL INITIALIZATIONS. THE NAM...SPECIFICALLY...IS
ATROCIOUS AND HAS AFFECTED OTHER SOLUTIONS SUCH AS
CONSRAW...BCCONSRAW...CONSALL...ETC. THIS HAS RENDERED MUCH OF THESE
DATA RATHER USELESS FOR MAXIMUM TEMPERATURE AND WIND FIELDS.
I WENT CLOSER TO CONSRAW OUTPUT FOR MINIMUM TEMPERATURES FRIDAY
NIGHT AS THIS OUTPUT SEEMED TO BE LARGELY UNAFFECTED BY THE
ERRONEOUS SNOWPACK AND THIS OUTPUT TENDS TO DO BEST FOR LOW
TEMPERATURES FOR THE LAST NIGHT BEFORE A COLD FRONT PASSAGE. THE
SREF ADVERTISES QUITE A BIT OF FOG FOR FRIDAY NIGHT...ESPECIALLY IN
OUR EAST...BUT WITH A SOUTHWEST WIND THAT WILL NOT BE PARTICULARLY
LIGHT...I AM DISCOUNTING THIS ADVERTISEMENT.
SATURDAY WILL BE TRICKY AS THE AFOREMENTIONED TROUGH TO THE NORTHWEST
SWEEPS RATHER QUICKLY INTO THE PLAINS...JOINING WITH ANOTHER TROUGH
SWINGING DOWN FROM CANADA TO REINFORCE A SIGNIFICANT SHOT OF MUCH
COLDER AIR. THE TRICKY PART WILL BE TIMING THE ASSOCIATED COLD
FRONT. MODEL SOLUTIONS GENERALLY CONCUR THAT MOST OF THE CWA SHOULD
BE ABLE TO GET IN ONE MORE DAY OF GOOD WARM AIR ADVECTION AHEAD OF
THE COLD FRONT BEFORE IT COMES IN. THE FAR WESTERN AND NORTHERN CWA
ARE MOST AT RISK OF NOT REALIZING TEMPERATURES AS WARM OR WARMER
THAN WHAT OCCURRED ON FRIDAY. I INCREASED TEMPERATURES FOR MOST OF
THE CWA FROM THE PREVIOUS FORECAST...BUT KEPT TEMPERATURES IN THE FAR
WESTERN/NORTHWESTER CWA RATHER SIMILAR AS MEDIUM RANGE MODELS
INDICATE THAT THE COLD FRONT SHOULD MAKE ITS WAY JUST INTO THE CWA
BY NOON SATURDAY. HOWEVER...THE FORECAST FOR MID 50S FOR SATURDAY
COULD CRASH AND BURN RATHER EASILY IF THE COLD AIR COMES IN
FASTER...SO THE CONFIDENCE FOR HIGH TEMPERATURES...ESPECIALLY FROM
THE TRI-CITIES AND FARTHER NORTHWEST...IS NOT AS HIGH AS IT COULD
BE...ESPECIALLY WITH THE POOR MODEL OUTPUT AS OF LATE. HEIGHT RISES
ARE IMPRESSIVE ALONG WITH COLD AIR ADVECTION BEHIND THE COLD
FRONT...ALTHOUGH THESE VARIABLES REALLY TAKE HOLD LATER INTO SATURDAY
NIGHT. I RAISED WIND SPEEDS SIGNIFICANTLY FROM THE PREVIOUS FORECAST
BECAUSE OF THIS...AND WE SHOULD BE IN THE REALM OF WIND ADVISORY AS
FAR SOUTH AS THE TRI-CITIES...AND NOT TOO FAR FROM WIND ADVISORY
FARTHER SOUTH IN OUR CWA FOR SATURDAY NIGHT. THIS CONTINUES TO LOOK
LIKE A DRY FORECAST WITH THE PASSING OF THE COLD FRONT AS THE
MOISTURE PROFILE IS QUITE DRY...ALTHOUGH THERE COULD CERTAINLY BE
SOME STRATUS FOR AWHILE DUE TO THE STRONG COLD AIR ADVECTION AND A
FLURRY IS NOT COMPLETELY OUT OF THE QUESTION. ALTHOUGH MID-LEVELS
ARE QUITE DRY...ANY SATURATION WILL OCCUR AT TEMPERATURES FAR TOO
COLD TO SUPPORT FREEZING DRIZZLE. THE COMBINATION OF THE STRATUS AND
WIND SHOULD KEEP TEMPERATURES FROM BOTTOMING OUT TOO MUCH AND THE
TEMPERATURES FROM THE PREVIOUS FORECAST LOOK PERFECTLY REASONABLE.
JUDGING BY WHAT HAPPENED WITH THE LAST COLD SNAP...I SUSPECT THAT
MODELS ARE GOING TO WANT TO SCOOT THE COLD AIR TO THE EAST TOO
QUICKLY AS THE DEVELOPING UPPER LEVEL RIDGE TO THE WEST TRIES TO
BUILD EAST. THIS IS CONFIRMED BY ENSEMBLE TRENDS FROM THE ECMWF AND
THE GFS. I WENT COLDER THAN THE INITIALIZED ALLBLEND AND PREVIOUS
FORECASTS...ESPECIALLY FOR HIGHS SUNDAY AND MONDAY...AND ALSO LOWS
FOR SUNDAY NIGHT/MONDAY MORNING. THE CENTER OF THE SURFACE HIGH
SHOULD MAKE ITS WAY ACROSS THE CWA SUNDAY NIGHT/MONDAY MORNING TO
ALLOW WINDS TO DROP SIGNIFICANTLY. UNDER CLEAR/MOSTLY CLEAR SKIES
AND WIND BECOMING VERY LIGHT OR CALM NEAR THE CENTER OF THE SURFACE
HIGH...THIS SHOULD ALLOW TEMPERATURES TO REALLY TANK INTO THE SINGLE
DIGITS...AND THEY COULD TANK RELATIVELY EARLY IN THE
NIGHT...DEPENDING ON THE TIMING OF THE SURFACE HIGH.
ONE MORE THING OF NOTE...I STUCK IN A SLIGHT CHANCE OF SNOW IN THE
NORTHEASTERN CWA FOR WEDNESDAY FROM AN IMPULSE WITHIN NORTHWEST
FLOW. TIMING AND POSITIONING ARE DICEY...SO CHANCES OF PRECIPITATION
ARE NOT HIGH IN THE FORECAST. SINCE MORE THAN ONE MODEL SOLUTION
ADVERTISES A SHORTWAVE TROUGH MOVING IN AT ROUGHLY THIS TIME...IT IS
PRUDENT TO INTRODUCE THIS TO THE LONG TERM FORECAST.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z FRIDAY AFTERNOON)
ISSUED AT 1203 PM CST THU DEC 26 2013
VFR CEILINGS AND VISIBILITY WILL CONTINUE THROUGHOUT THE TAF VALID
PERIOD. WILL SEE THE WIND LIGHTEN AND BACK FROM NORTHWEST TO THE
SOUTHWEST THIS EVENING...WHICH IS A TYPICAL DIURNAL RESPONSE TO THE
LOSS OF DIURNAL HEATING. THERE COULD BE A FEW HIGH CLOUDS MOVING
IN TOMORROW MORNING.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
KS...NONE.
&&
$$
SHORT TERM...PFANNKUCH
LONG TERM...HEINLEIN
AVIATION...WESELY
AREA FORECAST DISCUSSION
NWS GRAND FORKS ND
249 PM CST THU DEC 26 2013
.SHORT TERM...(THIS EVENING THROUGH FRIDAY NIGHT)
ISSUED AT 248 PM CST THU DEC 26 2013
TEMPERATURES WILL BE THE MAIN FORECAST ISSUE FOR THE SHORT TERM.
NORTHWESTERLY FLOW ALOFT WILL CONTINUE OVER THE REGION UNTIL AN
UPPER TROUGH STARTS TO DIG INTO MONTANA FRIDAY NIGHT. UNTIL
THEN...CONDITIONS WILL BE FAIRLY QUIET FOR THE CWA. A WEAK
SHORTWAVE OVER MANITOBA TONIGHT MOVES OFF INTO ONTARIO BY FRIDAY.
THE CENTER OF THE SFC LOW AND MOST OF THE PRECIP WILL REMAIN TO
OUR NORTH. ALTHOUGH SOME SNOW MAY CLIP LAKE OF THE WOODS SO KEPT
LOW POPS GOING IN OUR FAR NORTHEAST. A GREATER IMPACT ON US WILL
BE WESTERLY SFC WINDS BEHIND THE SFC TROUGH AXIS. THESE WEST WINDS
AND SOME LINGERING STRATUS WILL KEEP TEMPS TONIGHT FROM DROPPING
TOO MUCH...STAYING IN THE SINGLE DIGITS ABOVE ZERO IN THE EAST AND
THE TEENS IN THE WEST. WEST WINDS WILL CONTINUE TO BRING WARM AIR
ADVECTION TO THE REGION THROUGH FRIDAY...WITH 850MB TEMPS GETTING
WELL ABOVE ZERO. TEMPS TODAY OVER CENTRAL ND HAVE CLIMBED INTO THE
UPPER 20S TO LOW 30S EVEN WITH CLOUD COVER...SO THINK THAT WITH A
LITTLE BIT OF SUN WE SHOULD GET INTO THE MID 30S OVER THE
SOUTHWESTERN COUNTIES WITH SLIGHT COOLER TEMPS FURTHER NORTHEAST.
THE WARM UP WILL NOT LAST LONG AS THE ARCTIC FRONT BEGINS TO MOVE
DOWN INTO THE CWA FRIDAY NIGHT. SOME LIGHT SNOW WILL BE POSSIBLE
ALONG THE FRONTAL BOUNDARY...MAINLY IN THE FAR NORTH FRIDAY NIGHT.
WITH VERY STRONG COLD AIR ADVECTION TEMPS SHOULD SEE A SHARP DROP
INTO THE SINGLE DIGITS EVEN WITH CLOUDS BY SATURDAY MORNING.
.LONG TERM...(SATURDAY THROUGH THURSDAY)
ISSUED AT 248 PM CST THU DEC 26 2013
SATURDAY AND SUNDAY...THE BITTER ARCTIC AIR MAKES AN UNWANTED
ENCORE WITH HIGH PRESSURE BUILDING IN. THE PRESSURE GRADIENT
BEHIND THE COLD FRONT WILL BE PRETTY TIGHT AND A GOOD DIRECTION
FOR FUNNELING RIGHT DOWN THE VALLEY. THERE WILL BE A DECENT
ADIABATIC LAPSE RATE TO 925MB...ALTHOUGH THE GFS AND NAM ARE
SHOWING ABOUT 25 TO 30 KTS TO MIX. THE ECMWF ON THE OTHER
HAND...HAS NEARLY 40 KTS RIGHT OFF THE DECK. CONTINUED THE STRONG
WINDS DURING THE DAY ON SATURDAY AND THE MENTION OF WIDESPREAD
BLOWING SNOW FOR AT LEAST PART OF THE RED RIVER VALLEY.
HOWEVER...DO NOT FEEL CONFIDENT AT THIS POINT TO GO WITH ANY KIND
OF HEADLINE AND WILL JUST KEEP THE SPS GOING. WINDS WILL BEGIN TO
DIMINISH AND SKIES CLEAR OUT SATURDAY NIGHT...ALLOWING A DROP TO
NEAR 20 BELOW. COLD HIGH PRESSURE WILL BRING QUIET CONDITIONS BUT
WILL KEEP TEMPS IN THE NEGATIVE NUMBERS FOR SUNDAY.
SUNDAY NIGHT THROUGH THURSDAY...A NORTHWEST FLOW UPPER PATTERN
WILL DOMINATE NEXT WEEK...WITH MINOR EMBEDDED SHORTWAVES IN THE
MON AND WED TIMEFRAME POSSIBLY BRINGING SOME LIGHT SNOW (MORE
LIKELY FLURRIES) TO THE DEVILS LAKE REGION. EXPECT THE WEEK TO BE
DRY FURTHER EAST IN EASTERN ND...THE VALLEY AND NORTHWEST AND WEST
CENTRAL MINNESOTA. ANY CLOUDS RESULTING FROM THE WEAK WAVES WILL
BE WELCOME...AS A FRIGID ARCTIC AIRMASS WILL BE IN PLACE FROM SUN
NIGHT THROUGH MID WEEK. TEMPS SHOULD BE IN THE 20S BELOW OVERNIGHT
THROUGH WED...UNLESS CLOUDS CAN PROVIDE SOME RELIEF.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z FRIDAY AFTERNOON)
ISSUED AT 1226 PM CST THU DEC 26 2013
THE LATEST RAP GUIDANCE IS SHOWING IFR CIGS OVER CNTRL ND GRADUALLY
SHIFTING EAST THROUGH THE NEXT 24 HOURS WHILE THE NAM/GFS MOS
GUIDANCE KEEPS CONDS MVFR. I WILL GO WITH THE RAP IDEA AS IT IS
VERIFYING WELL NOW...AND BRING IFR CIGS INTO THE VALLEY BY LATE AFTN
AND INTO TVF/BJI BY MIDNIGHT. THINGS SHOULD THEN START IMPROVING
ACROSS EASTERN ND BY MIDNIGHT...WITH LESS UNCERTAINTY WHEN IFR CIGS
WILL ERODE AT TVF/BJI...BUT DO EXPECT CLEARING BY END OF 18Z TAF
PERIOD.
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...NONE.
MN...NONE.
&&
$$
SHORT TERM...JR
LONG TERM...JR/SPEICHER
AVIATION...SPEICHER
AREA FORECAST DISCUSSION
NWS GRAND FORKS ND
1227 PM CST THU DEC 26 2013
.UPDATE...
ISSUED AT 1226 PM CST THU DEC 26 2013
MOST SIGNIFICANT SNOW HAS ENDED ACROSS THE CWA...ALTHOUGH A FEW
FLURRIES HAVE BEEN HANGING AROUND HERE AND THERE. ADJUSTED POPS TO
LOWER THEM IN THE FAR SOUTHEAST AND PUT IN A FLURRY MENTION UNTIL
MID AFTERNOON. CLOUDS WILL CONTINUE TO HANG AROUND MOST OF THE
AREA EXCEPT IN THE FAR NORTHEAST WHERE LAKE OF THE WOODS MAY SEE A
BIT OF CLEARING THIS AFTERNOON.
UPDATE ISSUED AT 941 AM CST THU DEC 26 2013
MADE SOME TWEAKS UPWARD FOR POPS IN OUR SOUTHEASTERN COUNTIES
DURING THE NEXT FEW HOURS AS FARGO AND A FEW OTHER SITES HAVE BEEN
REPORTING 1SM VISIBILITY WITH SNOW. CONTINUE TO THINK THAT
ACCUMULATIONS WILL BE AROUND AN INCH OR SO. BUMPED UP TEMPS IN THE
SOUTHWESTERN COUNTIES A DEGREE OR SO AS THEY ARE ONLY A FEW
DEGREES BELOW WHAT WE HAD GOING FOR HIGHS.
UPDATE ISSUED AT 700 AM CST THU DEC 26 2013
WATER VAPOR LOOP INDICATED SHORT WAVE TROUGH EXTENDED FROM SOUTHEAST
MAN TO SD. RADAR INDICATED LIGHT SNOW WAS OCCURRING AHEAD OF SHORT
WAVE TROUGH. PRECIPITATION WAS MOVING TO THE SOUTHEAST ABOUT 35
KNOTS. NO CHANGES ON THIS UPDATE.
&&
.SHORT TERM...(TODAY THROUGH FRIDAY)
ISSUED AT 403 AM CST THU DEC 26 2013
UPPER LEVEL RIDGE OFF THE PACIFIC NORTHWEST COAST WILL FLATTEN AND
SHIFT INTO THE PLAINS BY FRI. JET STREAM TO THE THE WEST WILL SHIFT
NORTH OF THE AREA BY FRI. SHOULD MAKE FOR RELATIVELY MILD TEMPS FRI.
BUMP HIGH TEMPS UP COUPLE DEGREES FOR FRI. LOWERED LOW TEMPS COUPLE
DEGREES FOR FRI NIGHT WITH SHALLOW ARCTIC AIR EXPECTED TO MOVE OUT OF
CANADA.
WATER VAPOR LOOP INDICATED A SHORT WAVE TROUGH FROM SOUTHWEST MAN TO
WESTERN ND AND WAS MOVING SOUTHEAST ABOUT 55 KNOTS. LIGHT SNOW
PRECEDED TROUGH. PRECIP SHOULD MOVE ACROSS THE SOUTH AND WEST ZONES
MAINLY THIS MORNING. SHIFTED PRECIP TODAY MORE SOUTH AND WEST.
SOME WARM ADVECTION PRECIP WILL BE POSSIBLE LATE TONIGHT IN FAR
NORTHEAST ZONES. ADDED LIGHT PRECIP FAR NORTHEAST ZONES FOR LATE
TONIGHT.
ADDED PRECIP IN THE NORTH FOR FRI EVENING AND SHIFTED PRECIP A
LITTLE FARTHER SOUTH LATE FRI NIGHT.
.LONG TERM...(FRIDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 403 AM CST THU DEC 26 2013
SAT THROUGH WED...
IT LOOKS LIKE A HIGH IMPACT EVENT FOR SAT INTO SAT NIGHT...WITH
FALLING AND BLOWING SNOW BECOME AN ISSUE. A STRONG ARCTIC FRONT
WILL PUSH QUICKLY THROUGH THE AREA ON SATURDAY FROM NORTH TO SOUTH.
THERE WILL BE A BAND OF 1-2 INCHES OF SNOW FOR MAINLY THE NORTHERN
1/3 OF THE AREA...WITH STRONG WINDS DEVELOPING BEHIND THE COLD
FRONT. THERE WILL BE ABOUT 30-40KT TO MIX PER GFS/NAM...WITH THE
ECMWF EVEN STRONGER NEAR 40KT AT 925MB. THERE WILL BE INTENSE LOW
LEVEL CAA AND THIS WILL AID MOMENTUM TRANSPORT. IF MODEL PROGS PROVE
CORRECT...THERE WILL BE BLOWING SNOW FOR THE RED RIVER VALLEY AND
POINTS WEST...WITH LOW VISIBILITIES POSSIBLE WHEN FALLING SNOW
COMBINES WITH BLOWING SNOW. IN ADDITION...DANGEROUS WIND CHILLS
FALLING TO 40 BELOW WILL DEVELOP BY SATURDAY NIGHT. WE WILL BEGIN TO
HIGHLIGHT THIS WINTER WEATHER HAZARD WITH AN SPS THIS MORNING.
FOR SUNDAY THROUGH TUE...EXPECT DRY AND BITTERLY COLD TEMPS WITH
TEMPS WELL BELOW NORMAL...WITH ARCTIC AIR IN PLACE.
FOR WED...SOME MODERATION IN TEMPS ARE POSSIBLE WITH SOME SNOW IN
WEAK WAA REGIME.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z FRIDAY AFTERNOON)
ISSUED AT 1226 PM CST THU DEC 26 2013
THE LATEST RAP GUIDANCE IS SHOWING IFR CIGS OVER CNTRL ND GRADUALLY
SHIFTING EAST THROUGH THE NEXT 24 HOURS WHILE THE NAM/GFS MOS
GUIDANCE KEEPS CONDS MVFR. I WILL GO WITH THE RAP IDEA AS IT IS
VERIFYING WELL NOW...AND BRING IFR CIGS INTO THE VALLEY BY LATE AFTN
AND INTO TVF/BJI BY MIDNIGHT. THINGS SHOULD THEN START IMPROVING
ACROSS EASTERN ND BY MIDNIGHT...WITH LESS UNCERTAINTY WHEN IFR CIGS
WILL ERODE AT TVF/BJI...BUT DO EXPECT CLEARING BY END OF 18Z TAF
PERIOD.
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...NONE.
MN...NONE.
&&
$$
UPDATE...JR
SHORT TERM...HOPPES
LONG TERM...DK
AVIATION...SPEICHER
AREA FORECAST DISCUSSION
NWS BISMARCK ND
1203 PM CST THU DEC 26 2013
.UPDATE...
ISSUED AT 1203 PM CST THU DEC 26 2013
THE LATEST SURFACE ANALYSIS SHOWS THE WARM FRONT ROUGHLY LOCATED
FROM ROLLA TO CARRINGTON...INTO JAMESTOWN AND OAKES. RADAR AND
OBSERVATIONS SHOW THAT PRECIPITATION IN EAST CENTRAL HAS
ENDED. PER FOG/STRATUS LOOP...LOW CLOUDS STRETCH ALONG AND EAST
OF A LINE FROM TIOGA TO HAZEN...BISMARCK TO OAKES. THE HRRR KEEPS
THESE LOW CLOUDS IN EAST CENTRAL THROUGH THE AFTERNOON AND CONCUR
BASED ON LATEST LOOP. HAVE DELAYED ANY BREAKS IN THE OVERCAST
CONDITIONS UNTIL 00Z FRIDAY EAST CENTRAL. ON THE OUTER EDGES NEAR
THE LINE MENTIONED ABOVE...EXPECT SOME EROSION THROUGH THE
AFTERNOON. REST OF FORECAST REMAINS IN GOOD STANDING.
UPDATE ISSUED AT 855 AM CST THU DEC 26 2013
THE LATEST SATELLITE IMAGERY AND SURFACE OBSERVATIONS SHOW MAINLY
A CLEAR SKY IN THE WEST WITH SOME HIGH CLOUDS. THIS TRANSITIONS INTO
BKN/OVC CONDITIONS ALONG AND EAST OF WARM FRONT WHICH IS ACROSS
CENTRAL NORTH DAKOTA. PER LATEST NAM12/RAP13...THE WARM FRONT WILL
MAKE IT TO A RUGBY/JAMESTOWN LINE BY 18Z TODAY. LIGHT SNOW IS
TAPERING OFF IN EAST CENTRAL AND THE JAMES RIVER VALLEY PER LATEST
RADAR IMAGERY. WILL CONTINUE TO TREND THE POPS BELOW MEASURABLE
FROM WEST TO EAST THROUGH 18Z PER LATEST RAP13/NAM12 AND PREVIOUS
FORECAST.
LATEST 12Z NAM SHOWS WARM AIR ADVECTION CONTINUING THROUGH THE
SHORT TERM WHICH PEAKS FRIDAY AFTERNOON. TIME HEIGHT CROSS
SECTIONS SHOW WEAK OMEGA/VERTICAL MOTION/CLOUDS IN TANDEM WITH THE
THERMAL/WARM AIR ADVECTION. THE HRRR/HIGH RESOLUTION RAPID REFRESH
MODEL SKY/CEILING FORECAST SHOWS THE MAIN AREA OF LOW CLOUDS THIS
MORNING WILL REMAIN OVER EAST CENTRAL NORTH DAKOTA THROUGH THE
AFTERNOON. MINOR ADJUSTMENTS TO SKY AND TEMPERATURE GRIDS THIS
MORNING TO FIT BETTER WITH SATELLITE AND CURRENT OBSERVATIONS.
OTHERWISE THE PREVIOUS FORECAST IS ON TRACK.
UPDATE ISSUED AT 619 AM CST THU DEC 26 2013
SNOW WAS ENDING ACROSS THE WEST AND CENTRAL. THE SNOW AREA NOW BE
EAST OF A MINOT TO BISMARCK LINE FOR A FEW MORE HOURS THIS
MORNING...ENDING BEFORE NOON. TEMPERATURES WILL WARM INTO THE 30S
ACROSS THE SOUTHWEST AND 20S EAST. CURRENT FORECAST LOOKS ON TRACK.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 345 AM CST THU DEC 26 2013
A WARM FRONT EXTENDED FROM A LOW OVER NORTHERN ALBERTA
SOUTHEASTWARD INTO SOUTHERN SASKATCHEWAN TO THE WESTERN DAKOTAS.
THIS TROUGH IS EXPECTED TO MOVE EAST THROUGH THE DEVILS LAKE AND
JAMES RIVER VALLEY AROUND SUNRISE. UPPER LEVEL SHORTWAVE ENERGY
MOVING SOUTHEAST...COMBINED WITH LOW LEVEL CONVERGENCE...WILL
SUPPORT LIFTING ALONG THE SURFACE TROUGH. LIGHT SNOW HAD ENDED AT
WILLISTON AND DICKINSON. IT APPEARS THE SNOW BAND WAS IN A
NORTH-SOUTH ORIENTED FASHION ROUGHLY 50 MILES WIDE. THIS AREA OF
SNOW HAD REACHED MINOT BY AROUND 230 AM CST AND SHOULD CONTINUE
EASTWARD. EXPECT LIGHT SNOW TO REACH THE BISMARCK AREA BEFORE 4 AM
CST...AND THEN REACHING THE JAMES RIVER VALLEY AREA BEFORE SUNRISE.
MILD PACIFIC AIR BEHIND THE WARM FRONT WILL RESULT IN WEST/SOUTHWEST
WINDS TODAY...AND ANOTHER RELATIVELY WARM DAY IN STORE. LOOKING AT
HIGHS FROM THE UPPER 30S SOUTHWEST TO THE MID/UPPER 20S IN THE
TURTLE MOUNTAINS AND JAMES VALLEY AREAS.
ANOTHER MILD NIGHT TONIGHT WITH ANOTHER CLIPPER-TYPE LOW MOVING
SOUTHEAST ACROSS SOUTHERN SASKATCHEWAN...KEEPING THE SURFACE
PRESSURE GRADIENT TIGHT ENOUGH FOR WEST/SOUTHWEST WINDS TO REMAIN
AROUND 10 TO 15 MPH OR SO. LOOKING AT LOWS TONIGHT FROM THE TEENS
CENTRAL TO 20S WEST.
.LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 345 AM CST THU DEC 26 2013
CONCERNS IN THE EXTENDED PERIOD FOCUS ON A CLIPPER SYSTEM
ENTERING THE STATE SATURDAY MORNING AND BRINGING SNOW AND BLOWING
SNOW ALONG WITH COLD WIND CHILLS TO THE REGION. PRIOR TO
THIS...FRIDAY WILL BE UNUSUALLY MILD AS WARMER AIR MOVES OVER THE
REGION FROM A CHINOOK FLOW REGIME. THIS COULD PUT A BIT OF A CRUST
ON THE SNOW COVER...ESPECIALLY SOUTHWEST WHERE HIGHS MAY REACH THE
LOWER 40S ON FRIDAY. ECMWF/GFS MODELS NOW BRING THE ARCTIC FRONT IN
SOONER IN THE DAY SATURDAY THAN PREVIOUS RUNS. EXPECT FALLING
DAYTIME TEMPERATURES ACROSS THE REGION...BUT ESPECIALLY NORTH
SATURDAY...WITH WIND CHILLS REACHING POSSIBLE WIND CHILL CRITERIA
SATURDAY NIGHT...SUNDAY NIGHT AND AGAIN MONDAY NIGHT. SNOW
AMOUNTS OF 1 TO 2 INCHES APPEAR REASONABLE ACROSS THE NORTH AND
THIS WILL AID IN BLOWING SNOW. RAISED THE WINDS ABOUT 5 TO 10 MPH
OVER THE ALLBLEND GUIDANCE FOR SATURDAY ACROSS THE NORTH CENTRAL
AND EAST. THIS RAISED THE BLOWING SNOW POTENTIAL AND WILL ISSUE A
SPECIAL WEATHER STATEMENT FOR THE COMBINATION OF SNOW AND BLOWING
SNOW SATURDAY AND SATURDAY EVENING. THE COLD AIR SETTLES IN
THROUGH THE REMAINDER OF THE PERIOD...WITH A SMALL MODERATION IN
TEMPERATURES ACROSS THE SOUTHWEST BY WEDNESDAY.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z FRIDAY AFTERNOON)
ISSUED AT 1203 PM CST THU DEC 26 2013
MVFR CIGS EXPECTED FROM KMOT/KBIS/KJMS THROUGH LATE AFTERNOON WITH
KISN AND KDIK VFR. A RETURN TO VFR CONDITIONS WILL COMMENCE AT
KMOT/KBIS JUST PRIOR TO 00Z FRIDAY...AND AROUND 01Z FRIDAY AT
KJMS. THEREAFTER AND THROUGH THE REST OF THE TAF PERIOD...EXPECT
VFR CONDITIONS AT ALL AERODROMES WITH SCT/BKN MID LEVEL CLOUDS.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...KS
SHORT TERM...JV
LONG TERM...WAA
AVIATION...KS
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
340 PM CST THU DEC 26 2013
.SHORT TERM...(THIS EVENING THROUGH FRIDAY)
ISSUED AT 340 PM CST THU DEC 26 2013
FOR EARLY THIS EVENING...A WEAKENING TROUGH WILL MOVE EAST INTO
EASTERN WISCONSIN. AS THIS OCCURS...THE OMEGA BETWEEN 750 AND
400 MB WILL QUICKLY WANE AND SO WILL THE LIGHT SNOW ALONG THE
INTERSTATE 94 CORRIDOR. LITTLE...IF ANY...ACCUMULATION IS
EXPECTED.
OVERNIGHT...WARM AIR ADVECTION WILL DEVELOP AHEAD OF AN
APPROACHING WARM FRONT MOVING OUT OF THE NORTHERN PLAINS.
850 MB TEMPERATURES WARM FROM AROUND -6C TO 0C BY SUNRISE
FRIDAY. IN ADDITION...OMEGA BETWEEN 600 AND 300 MB WILL RESULT IN
AN INCREASE IN THE MID AND HIGH CLOUDS. EARLIER TODAY...THE BUFKIT
SOUNDINGS WERE SHOWING THE MOISTURE DRAMATICALLY INCREASING BELOW
925 MB. AS A RESULT...THERE WAS SOME CONCERN OF SOME SHALLOW FOG
DEVELOPING ACROSS THE FORECAST AREA. HOWEVER THE LATEST RAP AND
NAM/WRF HAVE STARTED TO BACK AWAY FROM THIS SOLUTION.
ON FRIDAY...A WARM FRONT WILL MOVE QUICKLY EAST ACROSS THE AREA.
925 MB TEMPERATURES WARM FROM AROUND 0C INTO THE 2 TO 6C RANGE BY
SUNSET. THIS WILL RESULT IN HIGH TEMPERATURES WARMING INTO THE
LOWER TO MID 30S WHICH IS ABOUT 10 DEGREES ABOVE NORMAL.
.LONG TERM...(FRIDAY NIGHT THROUGH THURSDAY)
ISSUED AT 340 PM CST THU DEC 26 2013
ON SATURDAY...SOUTHWEST WINDS ALOFT WILL CONTINUE TO ADVECT WARM
AIR INTO THE REGION FROM THE CENTRAL AND SOUTHERN PLAINS. THIS
WILL ALLOW TEMPERATURES TO CLIMB INTO THE MID AND UPPER 30S.
ON SATURDAY NIGHT AND EARLY SUNDAY MORNING...A STRONG ARCTIC COLD
FRONT WILL MOVE QUICKLY SOUTH THROUGH THE FORECAST AREA. WITH MUCH
OF THE FLOW PRECEDING THIS FRONT BEING FROM THE WEST AND
SOUTHWEST...THERE WILL BE VERY LITTLE MOISTURE FOR THIS FRONT TO
WORK WITH. SOUNDINGS SUGGEST THAT AS THE MOISTURE INCREASES IN THE
LOW LEVELS THERE WILL NO ICE CRYSTALS AVAILABLE...BUT THIS QUICKLY
CHANGES ABOUT AN HOUR AFTER PRECIPITATION ONSET. AS A
RESULT...THERE MAY BE A BRIEF PERIOD OF FREEZING DRIZZLE PRIOR TO
THE PRECIPITATION CHANGING OVER TO SNOW. WITH MUCH OF THE FORCING
WITH THE LONG WAVE TROUGH MOVING QUICKLY EAST OF THE AREA...NOT
EXPECTING MUCH SNOW WITH THIS SYSTEM.
ON SUNDAY...STRONG COLD AIR ADVECTION WILL BE SEEN ACROSS THE
AREA. THE INITIAL SURGE WILL CAUSE TEMPERATURES TO FALL INTO THE 5
TO 15 DEGREE RANGE...AND THEN TEMPERATURES WILL STABILIZE FOR THE
REMAINDER OF THE DAY. NORTHWEST WINDS IN THE 15 TO 25 KNOT RANGE
WILL PRODUCE WIND CHILLS IN THE 0 TO 20 BELOW RANGE DURING THE
AFTERNOON. THERE IS ALSO SOME CONCERN THAT THERE MAY BE SOME
BLOWING AND DRIFTING SNOW...BUT THE CONFIDENCE WAS TOO LOW AT THIS
TIME TO BE INCLUDED IN THE FORECAST GRIDS AT THIS TIME. THIS WAS
MAINLY DUE TO THE POSSIBILITY THAT THE COLD AIR COULD POTENTIALLY
LOCK UP THE SNOW IN THE SNOW PACK AND PREVENT IT FROM MOVING.
FROM SUNDAY NIGHT INTO MONDAY MORNING...TEMPERATURES WILL FALL
INTO THE -5 TO 5 DEGREE RANGE AND THE NORTHWEST WINDS WILL REMAIN
IN THE 5 TO 15 KNOT RANGE. THIS WILL PRODUCE WIND CHILLS IN THE
-20 TO -35 DEGREE RANGE ACROSS THE ENTIRE AREA. LIKE THE PAST
COUPLE OF DAYS...EXPECT A WIND CHILL ADVISORY TO BE NEEDED FOR
THIS TIME PERIOD.
FROM MONDAY NIGHT INTO NEW YEARS DAY...ANOTHER ARCTIC COLD FRONT
WILL MOVE THROUGH THE AREA ON MONDAY NIGHT. THIS FRONT WILL BRING
EVEN COLDER AIR INTO THE REGION. THE GEM HAS THE COLDEST
TEMPERATURES WITH LOW TEMPERATURES FALLING INTO -15 TO -25 DEGREE
RANGE ON TUESDAY MORNING AND INTO THE -25 TO -45 DEGREE RANGE ON
WEDNESDAY MORNING. MEANWHILE THE GFS IS THE WARMEST WITH
TEMPERATURES RANGING FROM -5 TO 10F ON TUESDAY MORNING...AND FROM
-5 TO -20F ON WEDNESDAY MORNING. WITH THE ECMWF A FEW DEGREES
COLDER THAN THE MODEL CONSENSUS...WENT A 2 TO 4 DEGREES COLD THAN
THE ALL BLEND TEMPERATURES.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z FRIDAY AFTERNOON)
ISSUED AT 1200 PM CST THU DEC 26 2013
A WEAK UPPER LEVEL DISTURBANCE WILL PASS JUST NORTH OF THE TAF
SITES THIS AFTERNOON AND MAY GENERATE SOME FLURRIES OR VERY LIGHT
SNOW AT THE TAF SITES AS IT MOVES THROUGH. CANNOT RULE OUT A BRIEF
DROP TO MVFR CONDITIONS IF THE SNOW TRACKS FURTHER SOUTH...BUT
ANTICIPATE VFR CONDITION THROUGH THE AFTERNOON HOURS INTO EARLY
THIS EVENING. WARMER AIR MOVING IN ALOFT MAY HELP TO GENERATE SOME
AREAS OF FOG AND STRATUS TONIGHT. CONFIDENCE IS LOW ON THE STRATUS
DEVELOPING. THINKING SOME AREAS OF BR WILL BE THE MOST LIKELY
SCENARIO TONIGHT SO HAVE INTRODUCED A 3SM BR AT KLSE STARTING AT
07Z AND 5SM BR AT KRST STARTING AT 03Z. WILL HAVE TO KEEP A CLOSE
EYE THIS TONIGHT WITH THE FORECAST SOUNDINGS SHOWING SATURATION
NEAR THE SURFACE.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...BOYNE
LONG TERM...BOYNE
AVIATION...WETENKAMP
AREA FORECAST DISCUSSION
NWS MILWAUKEE/SULLIVAN WI
253 PM CST THU DEC 26 2013
.SHORT TERM...
.TONIGHT AND FRIDAY...FORECAST CONFIDENCE...MEDIUM
UPSTREAM RADAR AND OBSERVATIONS SHOW LIGHT SNOW CONTINUING TO FALL
ACROSS SOUTHEAST MINNESOTA AND NORTHWEST WISCONSIN. WILL THUS
PROBABLY SEE A CHANCE FOR LIGHT SNOW CONTINUE INTO THE
EVENING...WINDING DOWN BY LATE EVENING AS THE SHORTWAVE FINALLY
BEGINS TO MAKE IT THROUGH THE AREA. NOT MUCH MORE THAN A DUSTING TO
A TENTH OF AN INCH OR TWO OF SNOW EXPECTED FROM HERE ON OUT.
ONCE AGAIN...CONCERNED ABOUT LOW TEMPS FOR TONIGHT...AS MODELS
DIFFERING QUITE A BIT WITH THE EXTENT OF CLOUD COVER. BASED ON
LATEST SATELLITE AND NAM/RAP LOW LEVEL MOISTURE...HAVE TRENDED
CLOUDIER FOR TONIGHT AND THUS TOWARD THE MILDER MODEL SOLUTIONS.
WITH VERY LIGHT WINDS EXPECTED THOUGH...TEMPS COULD DROP A FAIR
AMOUNT BELOW FORECAST VALUES IN SPOTS WHERE ANY CLEARING DOES OCCUR.
LOOKS LIKE A BRIEF BREAK IN TRENDS FOR TOMORROW...WITH NO
PRECIPITATION EXPECTED AND HIGH TEMPS NEAR TO EVEN A COUPLE DEGREES
ABOVE AVERAGE VALUES.
FRIDAY NIGHT AND SATURDAY...FORECAST CONFIDENCE...HIGH
THE 250 MB NORTHERN STREAM JET IS ACROSS THE U.S. CANADIAN BORDER
WITH A LARGE JET MAX MOVING ACROSS THE LAKE SUPERIOR AREA FRIDAY
NIGHT. WEAK UPPER DIVERGENCE BEGINS SATURDAY. 700 MB WARM
ADVECTION OCCURS FRIDAY NIGHT AND SATURDAY. 700 MB UPWARD MOTION
BEGINS SATURDAY. 700 MB RH DECREASES EARLY FRIDAY EVENING AND
BEGINS TO MOISTEN SATURDAY. 850 MB RH IS RATHER DRY. AND NO
PRECIPITATION IS EXPECTED. THERE SHOULD BE A STRONG LOW LEVEL
INVERSION SATURDAY...SO WINDS WILL NOT MIX DOWN MUCH.
SATURDAY NIGHT AND SUNDAY...FORECAST CONFIDENCE...HIGH
THE RIGHT ENTRANCE REGION OF THE 250 MB JET MAX IS OVER WISCONSIN
SATURDAY NIGHT AS THE BROAD UPPER TROUGH MOVES INTO THE UPPER
MISSISSIPPI VALLEY SUNDAY. THE WEAK UPPER DIVERGENCE CONTINUES
SATURDAY NIGHT AND INTO SUNDAY MORNING. 700 MB COLD AIR ADVECTION
BEGINS SATURDAY NIGHT AND CONTINUES SUNDAY. THE 700 MB UPWARD
MOTION CONTINUES SATURDAY NIGHT THEN BECOMES DOWNWARD ON SUNDAY.
THE 700 MB RH NEVER SATURATES SATURDAY NIGHT THEN DRIES ON
SUNDAY. 850 MB LAYERS SATURATE LATE SATURDAY NIGHT BUT DRIES
SATURDAY AFTERNOON. DUE TO DRY AIR BETWEEN 3 AND 12 THSD FT AND
MOIST LOW LEVELS...SOME FREEZING DRIZZLE IS POSSIBLE SATURDAY
NIGHT WITH TEMPERATURES STILL ABOVE FREEZING AT 5 THSD FT.
A SURFACE COLD FRONT MOVES ACROSS SOUTHERN WISCONSIN SATURDAY
NIGHT WITH BRISK NORTH WINDS SUNDAY WITH FALLING TEMPERATURES.
LIGHT POST FRONTAL PRECIPITATION SHOULD BRING A DUSTING OF LIGHT
SNOW SATURDAY NIGHT. THE INVERSION REMAINS BUT LIFTS...WITH THE
UNSTABLE LAYERS BELOW 3 THSD FT. FLURRIES EXPECTED SUNDAY DUE TO
MOIST AND RATHER UNSTABLE LOW LEVELS ON SUNDAY.
.LONG TERM...
.SUNDAY NIGHT AND MONDAY...FORECAST CONFIDENCE...HIGH
THE 500 MB TROUGH AXIS MOVES ACROSS WISCONSIN WITH THE 00Z ECMWF
PUSHING TIT EAST QUICKER. STRONG COLD AIR ADVECTION CONTINUES
WITH 510 THICKNESS VALUES BY MONDAY MORNING. WIND CHILLS OF 20 TO
30 BELOW ZERO ARE LIKELY SUNDAY NIGHT INTO EARLY MONDAY.
THE 12Z GFS HAS HIGH PRESSURE OVER WISCONSIN MONDAY...WHILE THE
00Z ECMWF BRINGS SOME VERY LIGHT SNOW IN THE BAROCLINIC
ZONE...ESPECIALLY IN SOUTHWEST AREAS. THE GFS IS A LITTLE SLOWER
WITH THIS.
TUESDAY THROUGH THURSDAY...FORECAST CONFIDENCE...HIGH
A SECOND TROUGH DIGS INTO WISCONSIN...BUT THE BASE OF THE TROUGH
REMAINS OVER THE UPPER GREAT LAKES ON THE GFS. THE ECMWF IS A
LITTLE FASTER AND DEEPER. THEN THE FLOW IS MORE ZONAL ON THE ECMWF
WITH A LINGERING TROUGH OVER THE UPPER MISSISSIPPI VALLEY ON THE
GFS.
HIGH PRESSURE DOMINATES ACROSS THE GREAT LAKES TUESDAY AND
WEDNESDAY. WIND CHILLS OF 10 TO 20 BELOW ZERO ARE POSSIBLE
TUESDAY NIGHT INTO EARLY WEDNESDAY...BUT WINDS ARE LIGHTER ON THE
00Z ECMWF.
WARM AIR ADVECTION BEGINS THURSDAY AS THE HIGH MOVES EAST.
&&
.AVIATION/00Z TAFS/...
ON AND OFF LIGHT SNOW WILL CONTINUE INTO EARLY EVENING. COULD SEE
VISIBILITIES DOWN TO AROUND 4 MILES AT TIMES...WITH NOT MUCH MORE
THAN A DUSTING TO A TENTH OR TWO EXPECTED FROM HERE ON OUT. EXPECT
DRY WEATHER THEN FROM LATE EVENING THROUGH FRIDAY.
LATEST RAP AND NAM ARE SUGGESTING MOSTLY CLOUDY SKIES WILL LINGER
THROUGH MUCH OF THE NIGHT. HAVE TAFS REMAINING VFR...AS THE MAJORITY
OF UPSTREAM OBS ARE VFR. SEEING SOME MVFR MIXED IN THERE THOUGH...SO
WOULD NOT BE SURPRISED AT BRIEFLY LOWER CLOUDS THIS EVENING AND
OVERNIGHT. SHOULD SEE SOME BREAKS IN THE CLOUDS BY TOMORROW
MORNING...WITH A DECENT CHANCE AT SOME SUNSHINE BY LATE MORNING AND
AFTERNOON.
&&
.MKX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
LM...NONE.
&&
$$
TONIGHT/FRIDAY AND AVIATION/MARINE...DDV
FRIDAY NIGHT THROUGH THURSDAY...HENTZ
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
1200 PM CST THU DEC 26 2013
.SHORT TERM...(TODAY THROUGH FRIDAY)
ISSUED AT 335 AM CST THU DEC 26 2013
MAIN WEATHER HAPPENINGS WILL BE MORE LIGHT SNOW FOR TODAY...THEN
SOME MODERATION IN TEMPERATURES ON FRIDAY.
WATER VAPOR SATELLITE LOOP COUPLED WITH RAP 500MB ANALYSIS SHOWS THE
NATION DOMINATED BY A LONG WAVE TROUGH OF LOW PRESSURE WITH
NORTHWEST FLOW INTO THE UPPER MISSISSIPPI RIVER VALLEY REGION. AN
EMBEDDED SHORT WAVE TROUGH WAS MOVING INTO THE DAKOTAS EARLY THIS
MORNING...TOWARD OUR FORECAST AREA. MEANWHILE...IR SATELLITE/SURFACE
OBSERVATIONS SHOWING STRATUS CLOUDS ENSHROUDING THE REGION...TRAPPED
UNDER A WEAK RIDGE OF HIGH PRESSURE THAT EXTENDED FROM THE MID AND
UPPER MISSISSIPPI RIVER VALLEY REGIONS INTO NORTHERN MN. RADAR
MOSAIC AND SURFACE OBSERVATIONS SHOWING SOME LIGHT SNOW FLURRY
ACTIVITY ACROSS PORTIONS OF WEST CENTRAL WISCONSIN AND ACROSS CENTRAL
AND NORTHERN MN. LIGHT SNOW WAS FALLING WITH A BIT MORE FERVOR
ACROSS PORTIONS OF ND IN ADVANCE OF THAT MID-LEVEL TROUGH WITH SOME
VISIBILITY RESTRICTIONS IN THE 4-5SM RANGE.
WILL BE WATCHING THAT MID-LEVEL TROUGH MOVE FROM THE DAKOTAS INTO
OUR REGION BY MID-MORNING WITH DECENT ISENTROPIC LIFT DEPICTED BY
THE NAM AND RAP ON THE 275K SURFACE...OR MAINLY IN THE 900-800MB
LAYER. WILL LIKELY SEE SNOW AMOUNTS IN THE 1/2 TO 1 INCH RANGE
THROUGH THE DAY WITH THIS WAVE BEFORE IT DEPARTS SOUTHEAST BY THIS
EVENING. OTHERWISE...LOOK FOR HIGHS TODAY IN THE TEENS ACROSS NORTH
CENTRAL WI...TO THE MID/UPPER 20S ELSEWHERE.
SOME LINGERING VERY LIGHT SNOW MAY STILL BE SEEN THIS EVENING EAST
OF THE MISSISSIPPI ON THE TAIL END OF THE PASSING TROUGH...BUT THEN
CLOUDS ARE EXPECTED TO DECREASE AFTER MIDNIGHT FROM SOUTHWEST TO
NORTHEAST AS A WEAK RIDGE OF HIGH PRESSURE BUILDS IN BEHIND THE
DEPARTING WAVE.
MODERATING TEMPERATURES EXPECTED ON FRIDAY AS SOUTHWEST WINDS KICK
IN ON THE BACKSIDE OF THE DEPARTING HIGH AND IN ADVANCE OF LOW
PRESSURE MOVING ALONG THE U.S./CANADIAN BORDER. NAM AND ECMWF
BULLISH WITH 925MB TEMPERATURES WARMING INTO THE 0 TO +5C RANGE
WHEREAS THE GFS IS ONLY IN THE -2 TO +3C RANGE. MODEL CONSENSUS
YIELDS HIGHS IN THE UPPER 20S ACROSS CENTRAL WI...TO THE LOWER 30S
FOR AREAS SOUTHWEST OF THE I-94 CORRIDOR. HOWEVER...SOUTHWEST WINDS
IN THE 10-20MPH RANGE WILL MAKE IT FEEL MORE LIKE THE UPPER TEENS TO
LOWER 20S.
.LONG TERM...(FRIDAY NIGHT THROUGH NEW YEARS DAY)
ISSUED AT 335 AM CST THU DEC 26 2013
WARM AIR ADVECTION WILL CONTINUE FRIDAY NIGHT INTO SATURDAY AS THE
AREA REMAINS IN THE WARM SECTOR OF LOW PRESSURE MOVING ACROSS
SOUTHERN ONTARIO CANADA. LOOK FOR LOWS FRIDAY NIGHT IN THE LOW TO
MID 20S WITH HIGHS ON SATURDAY EXPECTED TO TOP OFF IN THE LOWER AND
MIDDLE 30S. AN ARCTIC COLD FRONT IS THEN SLATED TO DROP THROUGH THE
AREA SATURDAY NIGHT.
WILL HAVE TO KEEP AN EYE ON PRECIPITATION TYPE SATURDAY NIGHT AS THE
GFS BUFKIT SOUNDING HINTING AT LOW LEVEL SATURATION UP TO 800MB WITH
NO ICE PRESENT IN THE CLOUD AS THE FRONT MOVES IN. AS SUCH...ADDED
THE MENTION OF FREEZING DRIZZLE INTO THE WEATHER GRIDS ALONG WITH
THE CHANCE OF LIGHT SNOW. BY EARLY SUNDAY MORNING...IT APPEARS THE
SATURATED COLUMN WILL HAVE ICE PRESENT FOR ALL LIGHT SNOW.
BY SUNDAY MORNING...PLAN ON TEMPERATURES DROPPING INTO THE SINGLE
DIGITS AND TEENS ABOVE ZERO WITH ONLY A 2 TO 3 DEGREE RISE DURING
THE DAY SUNDAY. SOME LIGHT SNOW WILL STILL BE POSSIBLE MAINLY EAST OF
THE MISSISSIPPI RIVER. BRISK NORTHWEST WINDS WILL ADD TO THE CHILL
SUNDAY AS WELL WITH WIND CHILL VALUES FALLING INTO THE -15 TO
-25 DEGREE RANGE ACROSS SOUTHEAST MN/NORTHEAST IA IN
THE AFTERNOON.
VERY COLD WIND CHILLS WILL BE SEEN SUNDAY NIGHT...LASTING THROUGH
TUESDAY MORNING//COLDEST EARLY MONDAY MORNING// AS THE ARCTIC AIR
CONTINUES TO SPILL INTO THE REGION. WIND CHILL HEADLINES WILL LIKELY
BE NEEDED. LOWEST WIND CHILL VALUES MONDAY MORNING COULD BE AS LOW
AS -25 TO -35 DEGREES. SLIGHT MODERATION IN TEMPERATURES MAY BE SEEN
LATER TUESDAY THROUGH WEDNESDAY AS THE HEART OF THE ARCTIC AIR MOVES
MORE INTO THE GREAT LAKES REGION.
EMBEDDED SHORTWAVE TROUGHS EMBEDDED IN THE NORTHWEST FLOW WILL ALSO
GIVE THE AREA PERIODIC LIGHT SNOW CHANCES FROM MONDAY NIGHT THROUGH
WEDNESDAY.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z FRIDAY AFTERNOON)
ISSUED AT 1200 PM CST THU DEC 26 2013
A WEAK UPPER LEVEL DISTURBANCE WILL PASS JUST NORTH OF THE TAF
SITES THIS AFTERNOON AND MAY GENERATE SOME FLURRIES OR VERY LIGHT
SNOW AT THE TAF SITES AS IT MOVES THROUGH. CANNOT RULE OUT A BRIEF
DROP TO MVFR CONDITIONS IF THE SNOW TRACKS FURTHER SOUTH...BUT
ANTICIPATE VFR CONDITION THROUGH THE AFTERNOON HOURS INTO EARLY
THIS EVENING. WARMER AIR MOVING IN ALOFT MAY HELP TO GENERATE SOME
AREAS OF FOG AND STRATUS TONIGHT. CONFIDENCE IS LOW ON THE STRATUS
DEVELOPING. THINKING SOME AREAS OF BR WILL BE THE MOST LIKELY
SCENARIO TONIGHT SO HAVE INTRODUCED A 3SM BR AT KLSE STARTING AT
07Z AND 5SM BR AT KRST STARTING AT 03Z. WILL HAVE TO KEEP A CLOSE
EYE THIS TONIGHT WITH THE FORECAST SOUNDINGS SHOWING SATURATION
NEAR THE SURFACE.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...DAS
LONG TERM....DAS
AVIATION...WETENKAMP
AREA FORECAST DISCUSSION...UPDATED
NWS MILWAUKEE/SULLIVAN WI
1041 AM CST THU DEC 26 2013
.UPDATE...AGAIN...MAIN CONCERN IN THE ONGOING TODAY PERIOD IS
POPS/WX. CURRENTLY A SWATH OF A LIGHT SNOW/FLURRIES IS ORIENTED NW-
SE ACROSS MUCH OF THE CWA AND DOWN TO CHICAGO. IN REGARD TO
REFLECTIVITY TRENDS...THERE HAS BEEN A SLIGHT UPTICK IN REFLECTIVITY
VALUES THE LAST TWO AND HALF HOURS...WITH VALUES AROUND 20-TO 25 DBZ
AT 1030 AM. SFC OBS SHOW THE LOWEST SFC VIS AROUND 3-4 SM WITHIN
THIS AREA GENERALLY...SO ITS EXPECTED THAT IT CONTAINS MOSTLY LIGHT
SNOW T0 FLURRIES AT THE PERIPHERY.
AN APPROACHING S/W TROUGH AND VORT LOBE AT 500 HPA WILL BE
TRAVERSING THE CWA THIS AFTERNOON/EVENING. CURRENT FORECAST AND
EXPECTATION IS FOR LIGHT SNOW TO DEVELOP/BLOSSOM THIS AFTERNOON AND
EVENING IN ASSOCIATION WITH THIS WAVE. THOUGH A BIT CONCERNED GIVEN
THE DIFFERENCES IN MODEL OUTPUT. LATEST HRRR RUN AND DIFFERENT
FLAVORS OF WRF SHOW ZERO TO SCANT QPF WHILE THE COARSER GFS AND
ECMWF PUTS OUT A FEW HUNDREDTHS. DECENT WARM AIR ADVECTION IN THE
LOW-LEVELS AND A 850 HPA WAVE ARE PRESENT. OTHERWISE...MODEST UPWARD
VERTICAL ASCENT PRESENT AND PROXIMITY SOUNDINGS SHOW DECENT
SATURATION AND RH IN THE LOW-LEVELS AND IN THE DENDRITE GROWTH ZONE.
HOWEVER...OMEGA/UVV NOT THE STRONGEST OR CENTERED QUITE ON THE
DGZ...BUT LIFT SHOULD BE SUFFICIENT DESPITE THE LOW MOISTURE THAT IS
AVAILABLE. QPF FORECAST IS LOW AT JUST A COUPLE HUNDREDTHS AND
SNOW-LIQUID RATIOS ARE FCST AROUND 14:1-18:1...SO AMOUNTS AROUND
A HALF AN INCH EXPECTED. REST OF THE FORECAST WAS ADJUSTED FOR
LATEST TRENDS. THIS WILL HAVE TO BE MONITORED BUT POPS WERE KEPT
HIGH GIVEN THE LIFT. REST OF THE FORECAST PACKAGE WASNT ALTERED
MUCH...BUT WERE ADJUSTED FOR LATEST TEMP/WIND TRENDS.
&&
.AVIATION/18Z TAFS/...THERE WILL BE ON AND OFF LIGHT SNOW TODAY.
COULD SEE VISIBILITIES DOWN TO AROUND 3 MILES AT TIMES...WITH A
DUSTING TO A HALF OF AN INCH POSSIBLE BY EVENING. THE SNOW WILL
WIND DOWN THIS EVENING...WITH DRY WEATHER THEN EXPECTED OVERNIGHT
AND FRIDAY.
LOOKS LIKE MAINLY VFR CIGS THROUGH TOMORROW...THOUGH SOME MVFR CIGS
POSSIBLE AT TIMES THROUGH TONIGHT GIVEN UPSTREAM CONDITIONS.
&&
.PREV DISCUSSION... /ISSUED 347 AM CST THU DEC 26 2013/
SHORT TERM...
TODAY AND TONIGHT-FORECAST CONFIDENCE HIGH
LIGHT SNOW MAKING IT/S WAY TOWARD THE WESTERN CWA THIS MORNING WITH
FASTER ADVANCE OF WARM AIR ADVECTION AHEAD OF SHORT WAVE MOVING SE
FROM THE ERN DAKOTAS...SO HAVE BROUGHT POPS IN A BIT SOONER AND
RAISED THEM IN THE WEST LATER THIS MORNING.
STILL LOOKS LIKE THIS AFTERNOON WILL BE THE PRIME TIME PERIOD FOR
LIGHT SNOW... DIMINISHING FROM WEST TO EAST LATE IN THE AFTERNOON
INTO THE EARLY EVENING. KEPT CHANCE/SLIGHT CHANCE POPS THROUGH THE
EVENING...MAINLY IN THE EASTERN HALF OF THE CWA UNTIL 500 MB TROUGH
CLEARS TO THE EAST. LOW AMOUNTS OF QPF AVAILABLE SO IN SPITE OF
SNOW/LIQUID RATIOS AROUND 15:1 TO 17:1...WILL ONLY SEE BETWEEN 1/2
INCH TO 1 INCH ACROSS THE CWA..WHICH WILL BE ENOUGH TO SLICKEN UP
THE ROADS.
WARM ADVECTION BRINGS HIGHS UP TO THE LOWER TO MIDDLE 20S
TODAY...WITH EARLY CLOUDS AND ONLY WEAK COLD ADVECTION BEHIND THE
SHORT WAVE KEEPING LOWS IN THE LOW TO MID TEENS TONIGHT.
FRIDAY-FORECAST CONFIDENCE HIGH
RIDGE BUILDS OVER GREAT LAKES AREA WITH 60-100 METER 500 MB HEIGHT
RISES AND STRONG LOW LEVEL WARM ADVECTION. 45 KNOT WESTERLY JET
INCREASES 850 MB TEMP ABOUT 10C IN 24 HOURS TO THE +5C RANGE.
NATURALLY THERE WILL BE A LOW LEVEL INVERSION GIVEN THE SNOW
PACK...BUT TEMPERATURES WELL INTO THE 20S SEEM PLAUSIBLE AND EVEN
LOWER 30S ALONG THE ILLINOIS BORDER.
SATURDAY-FORECAST CONFIDENCE HIGH
SHORT WAVE TROUGH MOVES FROM NORTHERN ROCKIES INTO DAKOTAS WITH
LITTLE CHANGE IN HEIGHTS OVER WISCONSIN. HOWEVER...FLOW TILTS MORE
WESTERLY AND SHOULD CONTINUE TO ALLOW FOR STRONG WARMING INTO
GREAT LAKES AHEAD OF STRONG SURFACE COLD FRONT.
SURFACE LOW EXPECTED TO BE OVER SOUTHERN MINNESOTA OR IOWA BY THE
AFTERNOON...WITH SURGE OF +8C 850 MB AIR ACROSS SOUTHERN
WISCONSIN. AGAIN EXPECTING A STRONG LOW LEVEL INVERSION INDUCED BY
SNOWPACK. THE TOUGH CALL WILL BE IN THE WEST-SOUTHWEST TRAJECTORY
ALIGNED NEARLY PARALLEL WITH THE AXIS OF THE SNOW PACK FROM KANSAS
TO SOUTHERN IOWA/NORTHERN MISSOURI AND INTO NORTHERN ILLINOIS.
CERTAINLY WILL BE A STRONG THERMAL GRADIENT NEAR THE SOUTHERN EDGE
OF THE MELTING SNOWPACK ROUGHLY FROM KANSAS CITY TO BURLINGTON
IOWA TO CHICAGO...BUT HOW FAR NORTH THAT GETS IS IN DOUBT. 15-20
DEGREE THERMAL GRADIENTS FROM BARE GROUND TO SNOWPACK ARE NOT
UNCOMMON IN THESE SITUATIONS SO EXPECT IT TO GO FROM 30S TO 50S
ACROSS SOUTHERN WISCONSIN INTO CENTRAL ILLINOIS.
AT NIGHT...THE BRIEF MILD PARTY IS OVER AS SURFACE LOW MOVES
ACROSS SOUTHERN WISCONSIN INTO LOWER MICHIGAN AND NEXT POLAR BLAST
MOVES IN. MOST OF THE PRECIPITATION WILL SKIRT BY TO THE NORTH BUT
A SHALLOW LAYER OF MOISTURE BELOW THE FRONTAL INVERSION WILL
DEEPEN WITH TIME. SINCE THE BULK OF THE MOISTURE IS WARMER THAN
ABOUT -7 TO -5C IN THE SOUNDING...LOOKS MORE LIKE A FREEZING
DRIZZLE OR LIGHT FREEZING RAIN THERMAL PROFILE FOR A WHILE BEFORE
TURNING TO SNOW OR SNOW GRAINS TOWARD MORNING.
LONG TERM...
SUNDAY-FORECAST CONFIDENCE HIGH
850 MB TEMPS CRASH TO ABOUT -14C BY THE AFTERNOON WITH BRISK NORTH
WINDS USHERING IN FALLING TEMPERATURES. TEMPERATURES SHOULD FALL
THROUGH THE TEENS AND INTO THE SINGLE DIGITS BY EVENING. NOT MUCH
PRECIPITATION LIKELY ALTHOUGH GFS HAS A MORE AGGRESSIVE POST
FRONTAL FRONTOGENETIC LIGHT SNOW LOOK TO IT THAN OTHER MODELS AS
AMPLIFYING UPPER TROUGH APPROACHES. CIPS ANALOGS WHICH FOLLOW GFS
DO SHOW SURPRISINGLY HIGH (40%) PROBABILITIES OF 2+" SNOWS.
WIND CHILL READINGS SHOULD FALL BELOW ZERO IN THE EARLY EVENING
AND THEN INTO -20 TO -25F RANGE BETWEEN MIDNIGHT AND ABOUT 9 AM
MONDAY MORNING. CONFIDENCE CONTINUES TO INCREASE THAT A WIND CHILL
ADVISORY WILL BE NEEDED WITH THIS EVENT.
MONDAY-FORECAST CONFIDENCE MEDIUM
MAIN STORY WILL BE BITTER COLD. CIPS ANALOGS SHOW 50-70% CHANCE OF
BELOW ZERO TEMPERATURES FROM NORTH TO SOUTH ACROSS CWA. MORNING
LOWS WILL BE IN THE ZERO TO 10 BELOW RANGE. WIND CHILL VALUES ONLY
RISE TO ABOUT -10F DURING THE AFTERNOON WITH HIGHS IN THE SINGLE
DIGITS ABOVE ZERO.
WIND CHILLS WILL FALL BACK TO -15 TO -25F RANGE MONDAY EVENING
INTO TUESDAY MORNING. SO THERE WILL LIKELY BE A COUPLE OF
POSSIBILITIES FOR WIND CHILL ADVISORIES OR PERHAPS ONE LONG TWO
DAY HEADLINE FOR SIMPLICITY.
ALTHOUGH CONFIDENCE IN COLD IS HIGH...CONFIDENCE IN LIGHT SNOW
POTENTIAL IS RATHER LOW. TIMING OF WEAK CLIPPER LIKE SYSTEM RANGES
FROM MONDAY ON ECMWF TO TUESDAY FOR GFS AND CANADIAN GEMNH. BEST
BET IS TO STRING LOW POPS ACROSS BOTH DAYS TO COVER THE
POSSIBILITIES. CIPS ANALOGS DO SHOW 50% PROBS OF 2+" OF SNOW
DURING THE PERIOD. THE ECMWF 24 HOURS AGO HAD QUITE A BIT OF
QPF...BUT ONLY THE GEMNH HOLDS ONTO A DECENT AMOUNT IN THE 0.10 TO
0.20" RANGE.
TUESDAY-FORECAST CONFIDENCE LOW
NOT MUCH MODERATION IN TEMPERATURES EXPECTED AND MUCH OF THIS IS
DEPENDENT ON WEAK LOW PRESSURE WAVES AND CLOUD COVER. LEANING
TOWARD IT BEING ABOUT 5 DEGREES WARMER THAN MONDAY BUT STILL
BITTERLY COLD. NEW YEARS EVE ENTHUSIASTS IN THE LATE EVENING CAN
LOOK FORWARD TO TEMPERATURES AROUND ZERO AND WIND CHILL VALUES OF
10 TO 15 BELOW ZERO.
WEDNESDAY/NEW YEARS DAY-FORECAST CONFIDENCE MEDIUM
A BIT MORE MODERATION EXPECTED BUT STILL ON THE ORDER OF 10 DEGREES
BELOW NORMAL TO START OFF 2014.
AVIATION/12Z TAFS/...
A PERIOD OF SCATTERED CIGS AND VFR VSBYS WITH WEAK SURFACE RIDGING
BETWEEN UPPER WAVES ...BUT VFR LEVEL CLOUDS WILL QUICKLY SPREAD OVER
THE REGION EARLY THIS MORNING. LIGHT SNOW WILL BE RETUNING TO KMSN
LATE THIS MORNING...AND EASTERN SITES THIS AFTERNOON...WITH WARM
ADVECTION AHEAD OF THE NEXT WAVE. UPSTREAM OBS INDICATE VFR CIGS
WITH VERY LIGHT SNOW...WITH PERIODS OF MVFR CIGS VSBYS EXPECTED FOR
2-3 HOURS MAINLY THIS AFTERNOON. ALL THE LIGHT SNOW WILL EXIT
EASTERN TAF SITES BY 06Z...WITH ONLY VERY LIGHT SNOW OR FLURRIES
AFTER THE 00Z-03Z TIME PERIOD.
MARINE...
WINDS WILL REMAIN BELOW SMALL CRAFT CRITERIA UNTIL FRIDAY AFTERNOON/
EVENING...WHICH BEGINS A PERIOD OF SMALL CRAFT CONDITIONS AS A
SERIES OF LOW PRESSURE SYSTEMS CROSS THE GREAT LAKES REGION FOLLOWED
BY AN ARCTIC AIRMASS BUILDING IN SUNDAY NIGHT AND MONDAY.
&&
.MKX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
LM...NONE.
&&
$$
UPDATE...ET/DDV
TODAY/TONIGHT AND AVIATION/MARINE...REM
FRIDAY THROUGH WEDNESDAY...CRAVEN