Forecast Discussions mentioning any of
"HRRR" "RAP" "RR" "RUC13" "RUC" received at GSD on 11/25/15
AREA FORECAST DISCUSSION
NWS CHARLESTON SC
1221 PM EST MON NOV 23 2015
...FROST AND FREEZE CONDITIONS TONIGHT...
.SYNOPSIS...
HIGH PRESSURE WILL EXTEND ACROSS THE REGION THROUGH THE END OF THE
WEEK. A WEAK COASTAL TROUGH COULD FORM DURING THE MIDDLE OF THE WEEK
JUST OFF THE SOUTHEAST COAST. A COLD FRONT IS EXPECTED TO DROP
THROUGH THE AREA FROM THE NORTH OVER THE WEEKEND...FOLLOWED BY A
STORM SYSTEM FROM THE WEST EARLY NEXT WEEK.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
NO CHANGES WERE NEEDED FOR THE EARLY AFTERNOON UPDATE. SEE THE
SHORT TERM PERIOD BELOW FOR INFORMATION ABOUT CHANCES TO THE
FROST/FREEZE HEADLINES.
HIGH PRESSURE WILL EXTEND ACROSS THE REGION TODAY. LOW-LEVEL
THICKNESS SCHEMES COUPLED WITH THE LATEST RAP FORECAST SOUNDINGS
SUPPORT HIGHS FROM THE LOWER 50S NORTH TO THE UPPER 50S ALONG THE
ALTAMAHA RIVER.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH THURSDAY/...
TONIGHT...CANADIAN HIGH PRESSURE WILL BECOME CENTERED JUST THE
NORTH OVERNIGHT AS HEIGHTS BUILD ALOFT IN THE WAKE OF THE
DEPARTING LONGWAVE TROUGH OFF NEW ENGLAND. THE BOUNDARY LAYER IS
POISED TO DECOUPLE QUICKLY AFTER SUNSET WITH CALM WINDS
DOMINATING FOR MOST LOCATIONS. CALM WINDS...LOW DEWPOINTS AND
CLEAR SKIES WILL PROMOTE STRONG RADIATIONAL COOLING WITH THE
STEEPEST THERMAL DECLINES OCCURRING DURING THE EVENING HOURS. THE
23/12Z GUIDANCE HAS TRENDED SLIGHTLY COOLER SO CONFIDENCE HAS
INCREASED ENOUGH TO UPGRADE THE REMAINING FREEZE WATCH AREA TO A
FREEZE WARNING. A FROST ADVISORY HAS ALSO BEEN ISSUED FOR INLAND
MCINTOSH COUNTY WHERE SCATTERED FROST IS LIKELY...BUT A FREEZE IS
NOT AS CERTAIN. FREEZE DURATIONS OF 5-8 HOURS ARE LIKELY ACROSS
THE FAR INLAND COUNTIES WITH 2-4 HOURS FARTHER EAST AND SOUTH. A
FREEZE IS UNLIKELY FOR DOWNTOWN CHARLESTON AND THE HEART OF
DOWNTOWN SAVANNAH. LOWS WILL RANGE FROM THE UPPER 20S WELL INLAND
TO THE UPPER 40S ALONG THE BEACHES OF NORTH COASTAL GEORGIA.
THERE WILL BE A LARGE THERMAL GRADIENT ACROSS THE SOUTH CAROLINA
COASTAL ZONES TONIGHT WITH TEMPERATURES RANGING FROM 31-32 WEST
OF HIGHWAY 17 AND OUTSIDE OF THE 526 LOOP WITH UPPER 30S IN
DOWNTOWN CHARLESTON AND MID 40S AT THE BEACHES. FOR THE GEORGIA
COASTAL ZONES...THERE MAY BE JUST ENOUGH OF AN ONSHORE COMPONENT
THERE TO KEEP TEMPERATURES WARM ENOUGH TO PRECLUDE SCATTERED
FROST. WILL HOLD OFF ON A FROST ADVISORY FOR THOSE ZONES...ALTHOUGH
IT MAY BE CLOSE IN COMMUNITIES SUCH AS BETHESDA...FAR WESTERN
PORTIONS OF SKIDAWAY ISLAND...HALFMOON LANDING...SHELLMAN BLUFF
AND DARIEN. LOWS LOOK TO GO NO LOWER THAN THE UPPER 40S FOR THE
IMMEDIATE GEORGIA COAST...INCLUDING TYBEE ISLAND.
TUESDAY AND TUESDAY NIGHT...BENEATH A NEARLY ZONAL FLOW ALOFT...A
LARGE AREA OF HIGH PRESSURE WILL BUILD INTO THE REGION FROM THE
NORTHWEST. A VERY DRY ATMOSPHERIC COLUMN WILL RESULT IN MAINLY CLEAR
SKIES THROUGH AT LEAST TUESDAY EVENING. TEMPERATURES WILL REMAIN
BELOW NORMAL...BUT START A SLOW MODERATING TREND WITH HIGHS IN THE
LOWER 60S AND NIGHTTIME LOWS IN THE MID TO UPPER 30S WELL INLAND AND
LOWER TO MID 40S CLOSER TO THE COAST...BUT NEAR 50 ALONG PARTS OF
THE IMMEDIATE GEORGIA COAST.
WEDNESDAY AND WEDNESDAY NIGHT...THE SURFACE HIGH WILL BUILD
SOUTHWARD INTO THE REGION AS IT SHIFTS ACROSS NEW ENGLAND ON
WEDNESDAY AND EVENTUALLY EAST OF NOVA SCOTIA WEDNESDAY NIGHT. AS
THIS OCCURS...A WEAK COASTAL TROUGH IS EXPECTED TO TAKE SHAPE JUST
OFF THE SOUTHEAST U.S. COAST. AN ENHANCED NORTHEAST FLOW WILL ADVECT
LOW LEVEL MOISTURE ONSHORE RESULTING IN AN INCREASE IN CLOUD COVER.
ISOLATED SHOWERS COULD DEVELOP ALONG THE IMMEDIATE SOUTHEAST GEORGIA
COAST ON WEDNESDAY...AND BECOME MORE PROBABLE FOR ALL COASTAL AREAS
BY WEDNESDAY NIGHT. HIGHS DURING THE DAY WILL BE IN THE MID 60S MOST
AREAS...WITH LOWS WEDNESDAY NIGHT RANGING FROM THE MID 40S WELL
INLAND TO THE MID 50S ALONG THE GEORGIA COAST.
THANKSGIVING DAY...UPPER LEVEL RIDGING WILL EXPAND OVER THE REGION
FROM THE SOUTHERN GULF OF MEXICO AS SURFACE HIGH PRESSURE SHIFTS
WELL OUT INTO THE ATLANTIC...HELPING TO MAINTAIN A NORTHEAST FLOW
ACROSS THE AREA. ISOLATED SHOWERS WILL STILL BE POSSIBLE FOR COASTAL
AREAS GIVEN THE INFLUX OF ATLANTIC MOISTURE AND SOME LOW LEVEL
CONVERGENCE NEAR THE COAST. BENEATH THE STRENGTHENING RIDGE...HIGHS
SHOULD BE IN THE UPPER 60S TO AROUND 70 ACROSS THE AREA.
&&
.LONG TERM /THURSDAY NIGHT THROUGH SUNDAY/...
UPPER LEVEL RIDGING WILL EXTEND OVER THE REGION FROM THE GULF OF
MEXICO LATE IN THE WEEK INTO THE START OF THE WEEKEND...BEFORE
FLATTENING OUT AS AN UPPER LEVEL TROUGH PASSES OFF THE MID-ATLANTIC
COAST LATE SATURDAY AND SATURDAY NIGHT. A POTENT UPPER LEVEL LOW
WILL THEN TRACK EASTWARD FROM THE NORTHERN PLAINS TO THE UPPER
MISSISSIPPI VALLEY/OHIO VALLEY LATE IN THE WEEKEND INTO EARLY NEXT
WEEK. MEANWHILE AT THE SURFACE...HIGH PRESSURE WILL PREVAIL OVER THE
AREA ON FRIDAY. MODELS THEN DIVERGE WITH THE GFS INDICATING A
BACKDOOR COLD FRONT DROPPING THROUGH THE AREA OVER THE WEEKEND...BUT
THE ECMWF KEEPS THE FRONT TO THE NORTH. A STORM SYSTEM THEN
APPROACHES FROM THE WEST EARLY NEXT WEEK.
AS FOR EXPECTED WEATHER CONDITIONS...RAIN-FREE CONDITIONS WILL
PREVAIL ON FRIDAY AND SATURDAY...BUT A SLIGHT CHANCE OF SHOWERS IS
POSSIBLE ON SUNDAY DEPENDING ON THE POSITION OF THE FRONT. RAIN
PROBABILITIES THEN INCREASE WELL INTO THE CHANCE CATEGORY SUNDAY
NIGHT THROUGH MONDAY WITH THE APPROACHING STORM SYSTEM. TEMPERATURES
WILL RISE ABOVE NORMAL FRIDAY AND SATURDAY...THEN LIKELY FALL BELOW
NORMAL FOR SUNDAY AND MONDAY.
&&
.AVIATION /17Z MONDAY THROUGH FRIDAY/...
VFR.
EXTENDED AVIATION OUTLOOK...VFR.
&&
.MARINE...
TODAY AND TONIGHT...HIGH PRESSURE WILL BUILD INTO THE AREA MEANING
GENERALLY IMPROVING CONDITIONS AS THE PRESSURE GRADIENT AND COLD
ADVECTION DIMINISH. A SMALL CRAFT ADVISORY REMAINS IN EFFECT FOR
THE GEORGIA OFFSHORE WATERS UNTIL 7 PM.
TUESDAY THROUGH SATURDAY...HIGH PRESSURE WILL CONTINUE TO BUILD OVER
THE WATERS AND PERSIST INTO MID-WEEK. A TROUGH OF LOW PRESSURE WILL
THEN DEVELOP MID-WEEK...LEADING TO A STRONGER PRESSURE GRADIENT OVER
THE COASTAL WATERS WITH ENHANCED NORTHEAST FLOW. SMALL CRAFT
ADVISORIES APPEAR TO RETURN ON WEDNESDAY FOR MOST WATERS OUTSIDE THE
CHARLESTON HARBOR...AND COULD PERSIST INTO AT LEAST LATE WEEK.
&&
.TIDES/COASTAL FLOODING...
TIDE LEVELS WILL BE ELEVATED THROUGH THE WEEK DUE TO THE FULL
MOON...LUNAR PERIGEE AND PERSISTENT NORTHEAST WINDS. TIDAL
FLOODING COULD REACH MODERATE LEVELS BY THE TUESDAY MORNING HIGH
TIDE...AND MINOR TO MODERATE TIDAL FLOODING WILL THEN BE POSSIBLE
WITH EACH HIGH TIDE CYCLE THROUGH AT LEAST MID-WEEK...IF NOT
LONGER. THE MORNING HIGH TIDE CYCLE APPEARS TO BE THE GREATER OF
THE TWO...AND THERE IS INCREASING CONCERN THAT MAJOR COASTAL
FLOODING COULD BE AN ISSUE WEDNESDAY AND POSSIBLY THURSDAY MORNING
GIVEN STRONG NORTHEAST WINDS JUST OFFSHORE.
&&
.CHS WATCHES/WARNINGS/ADVISORIES...
GA...FREEZE WARNING FROM 1 AM TO 9 AM EST TUESDAY FOR GAZ087-088-
099>101-114>116-118-137-138.
FROST ADVISORY FROM 4 AM TO 9 AM EST TUESDAY FOR GAZ140.
SC...FREEZE WARNING FROM 1 AM TO 9 AM EST TUESDAY FOR SCZ040-
042>045-047>052.
MARINE...SMALL CRAFT ADVISORY UNTIL 7 PM EST THIS EVENING FOR AMZ374.
&&
$$
ST
AREA FORECAST DISCUSSION
NWS CHARLESTON SC
928 AM EST MON NOV 23 2015
...WIDESPREAD FROST AND FREEZE CONDITIONS LIKELY TONIGHT AWAY FROM
THE COAST...
.SYNOPSIS...
HIGH PRESSURE WILL EXTEND ACROSS THE REGION THROUGH THE END OF THE
WEEK. A WEAK COASTAL TROUGH COULD FORM DURING THE MIDDLE OF THE WEEK
JUST OFF THE SOUTHEAST COAST. A COLD FRONT IS EXPECTED TO DROP
THROUGH THE AREA FROM THE NORTH OVER THE WEEKEND...FOLLOWED BY A
STORM SYSTEM FROM THE WEST EARLY NEXT WEEK.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
HIGH PRESSURE WILL EXTEND ACROSS THE REGION TODAY. LOW-LEVEL
THICKNESS SCHEMES COUPLED WITH THE LATEST RAP FORECAST SOUNDINGS
SUPPORT HIGHS FROM THE LOWER 50S NORTH TO THE UPPER 50S ALONG THE
ALTAMAHA RIVER. WINDS HAVE DIMINISHED ENOUGH ON LAKE MOULTRIE TO
CANCEL THE LAKE WIND ADVISORY A BIT EARLY. THE FORECAST IS VERY
MUCH ON TRACK AND DID NOT REQUIRE ANY MEANINGFUL CHANGES.
WITH REGARDS TO TONIGHT...A WIDESPREAD FREEZE IS EXPECTED ACROSS
INLAND AREAS. INCOMING DATA SUPPORT THE ONGOING FREEZE WARNING
AREA WHERE A FREEZE OF 4-7 HOURS IS LIKELY. THE FREEZE IS A BIT
MORE MARGINAL ACROSS ALONG THE LOWER SOUTH CAROLINA COASTAL
COUNTIES AND SOUTH OF THE I-16 CORRIDOR...THERE A FREEZE WATCH IS
CURRENTLY VALID. THE FREEZE WATCH WILL EITHER BE UPGRADED TO A
FREEZE WARNING OR A FROST ADVISORY LATER TODAY AFTER THE FULL
SUITE OF 12Z MODEL DATA ARE REVIEWED.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH THURSDAY/...
TONIGHT...HIGH PRESSURE WILL NUDGE CLOSER SETTING UP SOUTHEAST
MONDAY NIGHT...SETTING UP FAVORABLE RADIATIONAL COOLING. WITH
DEWPOINTS IN THE 20S TEMPERATURES WILL FALL QUICKLY AFTER SUNSET
AND SHOULD REACH NEAR 30 FOR MOST INLAND AREAS AND CLOSER TO 40
NEAR THE COAST. WE HAVE A FREEZE WARNING UP FOR NORTHERN AND
WESTERN PORTIONS OF THE FORECAST AREA WHERE THERE IS A HIGHER
LIKELIHOOD OF FREEZING TEMPERATURES...MAINLY NORTH AND WEST OF
CHARLESTON...BEAUFORT...SAVANNAH AND CLAXTON. ELSEWHERE EXCEPT
ALONG THE GEORGIA COAST THERE IS A FREEZE WATCH FOR THE POTENTIAL
OF FREEZING TEMPERATURES...MAINLY INLAND OF HWY 17 IN SOUTH
CAROLINA AND WEST OF I-95 IN GEORGIA. IN ADDITION...MOST AREAS
AWAY FROM THE IMMEDIATE COAST SHOULD SEE FROST SO THOSE FOLKS WITH
SENSITIVE VEGETATION ARE URGED TO TAKE PROPER PRECAUTIONS.
TUESDAY AND TUESDAY NIGHT...BENEATH A NEARLY ZONAL FLOW ALOFT...A
LARGE AREA OF HIGH PRESSURE WILL BUILD INTO THE REGION FROM THE
NORTHWEST. A VERY DRY ATMOSPHERIC COLUMN WILL RESULT IN MAINLY CLEAR
SKIES THROUGH AT LEAST TUESDAY EVENING. TEMPERATURES WILL REMAIN
BELOW NORMAL...BUT START A SLOW MODERATING TREND WITH HIGHS IN THE
LOWER 60S AND NIGHTTIME LOWS IN THE MID TO UPPER 30S WELL INLAND AND
LOWER TO MID 40S CLOSER TO THE COAST...BUT NEAR 50 ALONG PARTS OF
THE IMMEDIATE GEORGIA COAST.
WEDNESDAY AND WEDNESDAY NIGHT...THE SURFACE HIGH WILL BUILD
SOUTHWARD INTO THE REGION AS IT SHIFTS ACROSS NEW ENGLAND ON
WEDNESDAY AND EVENTUALLY EAST OF NOVA SCOTIA WEDNESDAY NIGHT. AS
THIS OCCURS...A WEAK COASTAL TROUGH IS EXPECTED TO TAKE SHAPE JUST
OFF THE SOUTHEAST U.S. COAST. AN ENHANCED NORTHEAST FLOW WILL ADVECT
LOW LEVEL MOISTURE ONSHORE RESULTING IN AN INCREASE IN CLOUD COVER.
ISOLATED SHOWERS COULD DEVELOP ALONG THE IMMEDIATE SOUTHEAST GEORGIA
COAST ON WEDNESDAY...AND BECOME MORE PROBABLE FOR ALL COASTAL AREAS
BY WEDNESDAY NIGHT. HIGHS DURING THE DAY WILL BE IN THE MID 60S MOST
AREAS...WITH LOWS WEDNESDAY NIGHT RANGING FROM THE MID 40S WELL
INLAND TO THE MID 50S ALONG THE GEORGIA COAST.
THANKSGIVING DAY...UPPER LEVEL RIDGING WILL EXPAND OVER THE REGION
FROM THE SOUTHERN GULF OF MEXICO AS SURFACE HIGH PRESSURE SHIFTS
WELL OUT INTO THE ATLANTIC...HELPING TO MAINTAIN A NORTHEAST FLOW
ACROSS THE AREA. ISOLATED SHOWERS WILL STILL BE POSSIBLE FOR COASTAL
AREAS GIVEN THE INFLUX OF ATLANTIC MOISTURE AND SOME LOW LEVEL
CONVERGENCE NEAR THE COAST. BENEATH THE STRENGTHENING RIDGE...HIGHS
SHOULD BE IN THE UPPER 60S TO AROUND 70 ACROSS THE AREA.
&&
.LONG TERM /THURSDAY NIGHT THROUGH SUNDAY/...
UPPER LEVEL RIDGING WILL EXTEND OVER THE REGION FROM THE GULF OF
MEXICO LATE IN THE WEEK INTO THE START OF THE WEEKEND...BEFORE
FLATTENING OUT AS AN UPPER LEVEL TROUGH PASSES OFF THE MID-ATLANTIC
COAST LATE SATURDAY AND SATURDAY NIGHT. A POTENT UPPER LEVEL LOW
WILL THEN TRACK EASTWARD FROM THE NORTHERN PLAINS TO THE UPPER
MISSISSIPPI VALLEY/OHIO VALLEY LATE IN THE WEEKEND INTO EARLY NEXT
WEEK. MEANWHILE AT THE SURFACE...HIGH PRESSURE WILL PREVAIL OVER THE
AREA ON FRIDAY. MODELS THEN DIVERGE WITH THE GFS INDICATING A
BACKDOOR COLD FRONT DROPPING THROUGH THE AREA OVER THE WEEKEND...BUT
THE ECMWF KEEPS THE FRONT TO THE NORTH. A STORM SYSTEM THEN
APPROACHES FROM THE WEST EARLY NEXT WEEK.
AS FOR EXPECTED WEATHER CONDITIONS...RAIN-FREE CONDITIONS WILL
PREVAIL ON FRIDAY AND SATURDAY...BUT A SLIGHT CHANCE OF SHOWERS IS
POSSIBLE ON SUNDAY DEPENDING ON THE POSITION OF THE FRONT. RAIN
PROBABILITIES THEN INCREASE WELL INTO THE CHANCE CATEGORY SUNDAY
NIGHT THROUGH MONDAY WITH THE APPROACHING STORM SYSTEM. TEMPERATURES
WILL RISE ABOVE NORMAL FRIDAY AND SATURDAY...THEN LIKELY FALL BELOW
NORMAL FOR SUNDAY AND MONDAY.
&&
.AVIATION /15Z MONDAY THROUGH FRIDAY/...
VFR.
EXTENDED AVIATION OUTLOOK...VFR.
&&
.MARINE...
TODAY AND TONIGHT...HIGH PRESSURE WILL BUILD INTO THE AREA MEANING
GENERALLY IMPROVING CONDITIONS AS THE PRESSURE GRADIENT AND COLD
ADVECTION DIMINISH. SMALL CRAFT ADVISORIES REMAIN UP FOR THE NEAR
SHORE WATERS THROUGH EARLY AFTERNOON AND BEYOND 20 NM THROUGH
AROUND MIDNIGHT.
TUESDAY THROUGH SATURDAY...HIGH PRESSURE WILL CONTINUE TO BUILD OVER
THE WATERS AND PERSIST INTO MID-WEEK. A TROUGH OF LOW PRESSURE WILL
THEN DEVELOP MID-WEEK...LEADING TO A STRONGER PRESSURE GRADIENT OVER
THE COASTAL WATERS WITH ENHANCED NORTHEAST FLOW. SMALL CRAFT
ADVISORIES APPEAR TO RETURN ON WEDNESDAY FOR MOST WATERS OUTSIDE THE
CHARLESTON HARBOR...AND COULD PERSIST INTO AT LEAST LATE WEEK.
&&
.TIDES/COASTAL FLOODING...
TIDE LEVELS WILL BE ELEVATED THROUGH THE WEEK DUE TO THE FULL
MOON...LUNAR PERIGEE AND PERSISTENT NORTHEAST WINDS. TIDAL
FLOODING COULD REACH MODERATE LEVELS BY THE TUESDAY MORNING HIGH
TIDE...AND MINOR TO MODERATE TIDAL FLOODING WILL THEN BE POSSIBLE
WITH EACH HIGH TIDE CYCLE THROUGH AT LEAST MID-WEEK...IF NOT
LONGER. THE MORNING HIGH TIDE CYCLE APPEARS TO BE THE GREATER OF
THE TWO...AND THERE IS INCREASING CONCERN THAT MAJOR COASTAL
FLOODING COULD BE AN ISSUE WEDNESDAY AND POSSIBLY THURSDAY MORNING
GIVEN STRONG NORTHEAST WINDS JUST OFFSHORE.
&&
.CHS WATCHES/WARNINGS/ADVISORIES...
GA...FREEZE WARNING FROM 1 AM TO 9 AM EST TUESDAY FOR GAZ087-088-
099>101.
FREEZE WATCH FROM LATE TONIGHT THROUGH TUESDAY MORNING FOR
GAZ114>116-118-137-138.
SC...FREEZE WARNING FROM 1 AM TO 9 AM EST TUESDAY FOR SCZ040-
042>045-047-052.
FREEZE WATCH FROM LATE TONIGHT THROUGH TUESDAY MORNING FOR
SCZ048>051.
MARINE...SMALL CRAFT ADVISORY UNTIL 1 PM EST THIS AFTERNOON FOR AMZ350-
352.
SMALL CRAFT ADVISORY UNTIL 1 AM EST TUESDAY FOR AMZ374.
SMALL CRAFT ADVISORY UNTIL 10 AM EST THIS MORNING FOR AMZ330.
&&
$$
ST
AREA FORECAST DISCUSSION
National Weather Service Lincoln IL
310 PM CST MON NOV 23 2015
.SHORT TERM...(Tonight)
ISSUED AT 310 PM CST MON NOV 23 2015
Main short-term forecast concern continues to be potential for fog
development tonight as high pressure slides overhead and winds go
light/variable. Several factors point to at least patchy fog,
including nearly calm winds after sunset and increasing boundary
layer moisture due to snow melt. However, the possible fly-in-the-
ointment will be increasing high clouds currently seen on visible
satellite imagery streaming from the Dakotas into Iowa.
All models suggest these clouds will spread into Illinois late
this afternoon then persist through much of the night. Whether
they will be thick enough to limit radiational cooling and prevent
widespread fog is still in question. Several models such as the
NAM and GFS indicate little or no restriction to visby tonight,
while the HRRR is showing fog developing from mid-evening through
the overnight hours. At this point, will mention patchy fog over the
snow cover, generally along/north of the I-74 corridor. Overnight
lows will be in the middle to upper 20s.
&&
.LONG TERM...(Tuesday through Monday)
ISSUED AT 310 PM CST MON NOV 23 2015
Upper level ridging will build into central IL Tuesday providing for
dry conditions with some mid and high cloud cover. The warming trend
will continue slowly with highs reaching the low to mid 40s I-74
northward where snow cover remains...to the low to mid 50s south of
I-70. Lows Tuesday night should drop to only the mid to upper 30s as
increased winds and cloud cover prevent further cooling at the
surface.
By Wednesday...this ridge will slip east of IL allowing increased
southerly flow and a plume of Gulf moisture to nudge eastward into
Illinois. The result will be a continued warming trend with highs
reaching around 50 north of I-74 to the upper 50s from I-70
southward. Chances for precipitation will be arriving in western
portions of the state by evening. 12Z models currently keep this
precipitation light until Thursday/Thanksgiving evening...then
spread heavier amounts around 0.50 inches per 6 hours across the
state from Thursday afternoon through Friday morning. Total rainfall
amounts look to be around 1 to 1.25 inches southeast of Champaign-
Decatur, and 1.5 to 1.75 inches to the northwest. Could see a mix of
light snow with the light rain over central IL Friday night before
ending. Highs Thursday should be in the mid 50s to around 60,
cooling to the low to mid 40s over the IL river valley to the mid to
upper 50s in southeast IL.
High pressure will build into the Midwest region on Saturday for a
good chance for dry conditions, although GFS is quicker returning
moisture back into central IL and perhaps some precipitation will
return Saturday night into Sunday if this turns out. Chance for
precipitation with this next system looks to linger through Monday.
&&
.AVIATION...(For the 18Z TAFS through 18Z Tuesday afternoon)
ISSUED AT 1150 AM CST MON NOV 23 2015
Main aviation forecast concern continues to be potential for fog
development tonight as high pressure slides overhead and winds go
light/variable. Several factors point to at least patchy fog,
including nearly calm winds after sunset and increasing boundary
layer moisture due to snow melt. However, the possible fly-in-
the-ointment will be increasing high clouds currently seen on
visible satellite imagery streaming from the Dakotas into Iowa.
All models suggest these clouds will spread into Illinois late
this afternoon then persist through much of the night. Whether
they will be thick enough to limit radiational cooling and prevent
widespread fog is still in question. Several models such as the
NAM and GFS indicate little or no restriction to visby tonight,
while the HRRR is showing fog developing from mid-evening through
the overnight hours. At this point, will continue to feature
visbys down to around 3SM tonight where snow cover exists at the
I-74 terminals, but will maintain unrestricted visbys at both KSPI
and KDEC.
&&
.ILX Watches/Warnings/Advisories...
NONE.
&&
$$
SHORT TERM...Barnes
LONG TERM...Onton
AVIATION...Barnes
AREA FORECAST DISCUSSION
National Weather Service Lincoln IL
1150 AM CST MON NOV 23 2015
.UPDATE...
ISSUED AT 950 AM CST MON NOV 23 2015
High pressure over the Deep South is providing a mild southwesterly
flow across central Illinois this morning. Thanks to abundant
sunshine, 15z/9am temperatures have already risen into the upper
30s and lower 40s across areas without a snow cover. Further north
over the deeper snow field, readings remain in the lower 30s
along/north of I-74. With only a few high/thin clouds expected to
stream into the area this afternoon, am expecting nearly full
sunshine and continued southwesterly winds. Based on current rate
of temp rise, have adjusted afternoon highs up a few degrees
across the southern two-thirds of the KILX CWA. Highs will range
from the upper 30s from Galesburg to Lacon...to around 50 degrees
along/southwest of a Jacksonville to Flora line.
&&
.SHORT TERM...(Today)
ISSUED AT 330 AM CST MON NOV 23 2015
A weak sfc trough will move through the CWA this morning, switching
southerly winds to westerly. Pressure gradient is currently tighter
ahead of this trough so winds this morning will be higher than this
afternoon, after the trough passes through and sfc ridging begins to
build into the area. Satellite trends indicate lots of clear skies
over the area for the day. Will see some warmer temps today, which
will melt some of the snow, but without any good waa on the sfc and
still fairly good snow pack in the north and northeast, the warmer
temps will be limited to mostly areas south of I-74. Temps over the
snow pack should still be above freezing, but overall below normal
temps expected today.
.LONG TERM...(Tonight through Sunday)
ISSUED AT 330 AM CST MON NOV 23 2015
Surface high pressure ridge settling into the southeast states
tonight and ridging nw into central IL will bring lighter winds to
the area tonight. These lighter winds along with boundary layer
moisture from snow melt will likely develop patchy fog over snow
pack of northern CWA later tonight into mid morning Tue. Models
continue to show streaks of mid/high clouds affecting central and
especially ne CWA tonight with weak upper level disturbances in wnw
flow. Main over level trof and short wave energy will be ne of IL
over the Great Lakes region where more cloud cover expected. Lows
tonight range from lower 20s north of Peoria to upper 20s sw CWA.
00Z models continue to show upper level ridge building into IL and
the ohio river valley Tue/Wed. Meanwhile surface high pressure
strengths as it moves into the mid Atlantic states and New England
Tue night into Wed. Increasing pressure gradient over IL Tue/Wed to
bring breezier south winds along with milder temperatures by Wed.
Highs Tue range from lower 40s from I-74 ne where lingering snow
pack to lower 50s sw CWA. Southeast winds of 8-15 mph on Tuesday.
Added patchy fog to northern CWA overnight Tue night until mid
morning Wed where more moisture from snow melt. Lows Tue night in
the low to mid 30s, with upper 30s from Springfield and Jacksonville
sw.
Strong cutoff upper level low/trof digging into northern CA by
12Z/Wed and moving into the central Rockies on Thanksgiving Day.
Increasing WAA and moisture well ahead of this storm system
possibly getting rain showers into the IL river valley later Wed and
Wed evening. Shower chances increase from nw to se overnight Wed
night into Thursday. Southeast IL likely to stay dry Wed night and
into Thu. Milder highs Wed near 50F from I-74 ne to mid 50s sw CWA
and in southeast IL. Highs Thu in the upper 50s to near 60F. Highest
chances of rain appears to be over the IL river valley Thu and
across the area Thu night and east of the IL river Friday. Better
chance of isolated thunderstorms appears to be sw of central IL Thu
and Thu night. But heavier rains of 1-1.5 inches with locally higher
amounts before diminishing from nw to se during Friday night. Could
see a mix of light snow with the light rain over central IL Friday
night especially overnight before ending. Highs Fri range from low
to mid 40s over IL river valley to the mid to upper 50s in southeast
IL.
High pressure builds into the Great Lakes region on Saturday and
Saturday night bringing cooler temperatures to IL along with drier
conditions. Lingered slight chances of light rain/snow over far
southern 6 counties closer to cold front pressing southward into the
TN river valley. GFS is quicker returning moisture back into central
IL Sunday while ECMWF model waits until Sunday night to bring back
precipitation. Will stay close to superblend pops for now that far
out.
&&
.AVIATION...(For the 18Z TAFS through 18Z Tuesday afternoon)
ISSUED AT 1150 AM CST MON NOV 23 2015
Main aviation forecast concern continues to be potential for fog
development tonight as high pressure slides overhead and winds go
light/variable. Several factors point to at least patchy fog,
including nearly calm winds after sunset and increasing boundary
layer moisture due to snow melt. However, the possible fly-in-
the-ointment will be increasing high clouds currently seen on
visible satellite imagery streaming from the Dakotas into Iowa.
All models suggest these clouds will spread into Illinois late
this afternoon then persist through much of the night. Whether
they will be thick enough to limit radiational cooling and prevent
widespread fog is still in question. Several models such as the
NAM and GFS indicate little or no restriction to visby tonight,
while the HRRR is showing fog developing from mid-evening through
the overnight hours. At this point, will continue to feature
visbys down to around 3SM tonight where snow cover exists at the
I-74 terminals, but will maintain unrestricted visbys at both KSPI
and KDEC.
&&
.ILX Watches/Warnings/Advisories...
NONE.
&&
$$
UPDATE...Barnes
SHORT TERM...Auten
LONG TERM...07
AVIATION...Barnes
AREA FORECAST DISCUSSION
NWS QUAD CITIES IA IL
547 PM CST TUE NOV 24 2015
.SYNOPSIS...
ISSUED AT 330 PM CST TUE NOV 24 2015
OTHER THAN PATCHY TO AREAS OF THIN CIRRUS...SKIES WERE SUNNY
ACROSS THE DVN CWA. MID AFTERNOON TEMPERATURES WERE IN THE MID TO
UPPER 30S ALONG HIGHWAY 20 WHERE THE DEEPEST SNOW COVER EXISTS...
TO THE LOWER 50S SOUTH OF HIGHWAY 34 WITH BARE GROUND.
&&
.SHORT TERM...(THIS EVENING THROUGH WEDNESDAY)
ISSUED AT 330 PM CST TUE NOV 24 2015
FORECAST FOCUS ON POTENTIAL FOR FOG AND CHANCE OF LIGHT RAIN ON
WEDNESDAY.
TONIGHT...A VEIL OF THICKENING CIRRUS WILL COVER THE CWA AS A
SHORT WAVE IN THE CENTRAL PLAINS MOVES ACROSS THE AREA IN THE
SOUTHWEST FLOW ALOFT. ALONG WITH SOUTHEAST TO SOUTH WINDS THIS
WILL MEAN TEMPERATURES WILL BE MUCH WARMER THAN THE PAST SEVERAL
NIGHTS. THE AIRMASS WILL STILL BE RATHER DRY SO BELIEVE FOG THAT
FORMS AFTER MIDNIGHT SHOULD REMAIN ON THE PATCHY SIDE. MINIMUM
TEMPERATURES WILL RANGE FROM THE LOWER 30S ALONG HIGHWAY 20 TO THE
UPPER 30S IN OUR FAR SOUTHERN CWA.
WEDNESDAY...SOUTHERLY WINDS WILL TRANSPORT INCREASING LOW LEVEL
MOISTURE FROM THE WESTERN GULF AS HIGH PRESSURE SITS OVER THE
SOUTHEAST UNITED STATES...AND A CLOSED LOW MOVES INTO NEVADA.
FORECAST SOUNDINGS INDICATE PWATS INCREASE TO 0.60 TO 0.80 INCHES
BY LATE AFTERNOON. WITH THE DETERMINISTIC MODELS SHOWING A 40 KNOT
LOW LEVEL JET FROM TX TO IA I DON`T SEE ANY REASON TO DISAGREE.
WITH THIS MOISTURE AND A COLD FRONT APPROACHING FROM THE WEST
THERE WILL BE A CHANCE OF SOME LIGHT RAIN OR DRIZZLE...MAINLY IN
THE AFTERNOON AND NEAR AND WEST OF THE MS RIVER. SKIES WILL ALSO
BECOME CLOUDY AS MODELS SPREAD/DEVELOP LOW STRATUS ACROSS THE CWA
DUE TO THE INCREASING LOW LEVEL MOISTURE...AND IT`S NOVEMBER.
MAXIMUM TEMPERATURES ARE EXPECTED TO RANGE FROM THE MID 40S ALONG
HIGHWAY 20 TO THE LOWER 50S IN OUR SOUTHERN CWA. HAASE
.LONG TERM...(WEDNESDAY NIGHT THROUGH NEXT TUESDAY)
ISSUED AT 330 PM CST TUE NOV 24 2015
WEDNESDAY NIGHT AND THURSDAY...STRENGTHENING AND DEEP
SOUTHWESTERLIES ON BACKSIDE OF LARGE ATLANTIC COAST RIDGE TO WARM-
MOIST ADVECT STRONGLY WED NIGHT...WITH PWAT/S PROJECTED TO SATURATE
TO 0.80 TO AROUND AND INCH BY DAYBREAK THU. MORE OF THE 12Z RUN
MODEL SOLUTIONS CONTINUE TO ADJUST WEST WITH MAIN NE-TO-SW ORIENTED
SFC FRONT ALIGNING UNDER THE FLOW...MAKING FOR MORE LLVL CONVERGENT
RAIN PRODUCTION/COVERAGE ACRS THE FAR NORTHWESTERN CWA LATE WED
NIGHT. THIS CONVERGENT AREA WHERE WINDS DROP OFF MAY BE WHERE THE
AREAS OF FOG FORM AFTER MIDNIGHT AS WELL. OTHERWISE THE REST OF THE
CWA JUST INCREASING PATCHY AREAS OF LIGHT RAIN OR DRIZZLE WITH A
SOUTH SFC BREEZE OF 10-15 MPH MAKING FOR STEADY TO SLOWLY RISING
TEMPS INTO THU MORNING. SEASONABLY STRONG WARM MOIST CONVEYOR IN
FULL SWING ON THU AND THU NIGHT EVENING...WITH THE MODELS HAVING
INCREASED PWATS TO VERY HIGH LEVELS FOR LATE NOVEMBER AND FROM
PREVIOUS RUNS...GENERALLY 1.1 TO 1.4 INCHES. THIS KIND OF SATURATION
COMBINED WITH DEEP VERTICAL LAYER POS OMEGAS EASILY SUPPORT A BAND
OF MODERATE RAINS RIDING UP ALONG THE FRONT AND POST-
FRONTALLY...SLOWLY PUSHING FROM WEST-TO-EAST THU INTO FRI MORNING
BEFORE CLEARING OFF TO THE EAST ACRS MOST OF THE AREA BY FRI
AFTERNOON. FURTHER WEST FRONTAL ADJUSTMENT SUPPORTS THE MOST
WIDESPREAD RAIN COVERAGE ALONG AND WEST OF THE MS RVR THROUGH 00Z
FRI...THEN PUSHING EAST THU NIGHT AND WILL BLANKET THE CWA WITH
HIGH/CATEGORICAL POPS ACCORDINGLY.
AGAIN BACK TO THE UNSEASONABLE SATURATION COMBINED WITH DURATION OF
LIFT...STILL SEE THE CWA GETTING WIDESPREAD 1-2 INCHES BY FRI
MORNING WHEN IT TAPERS OFF. BUT WILL ADJUST THE HEAVY RAINFALL AXIS
FURTHER WEST WITH LATEST THINKING AND ADVERTISE 1.5 TO 1.8+ INCHES
WEST OF A LINE FROM FREEPORT IL...TO THE QUAD CITIES AND TO KEOKUK
IA ON SOUTH ALONG THE MS RVR. 12-18 HOURS FOR THIS RAIN TO FALL WILL
HELP...BUT WILL CONTINUE TO TOUCH UPON THE ALREADY SATURATED
SOILS/SNOW MELT MAKING FOR MORE RUN-OFF THAN WHAT OCCURRED FOR AN
EVEN STRONGER EVENT BACK A WEEK AGO ON NOV 17TH. THUS SOME RIVER
LEVELS COULD REALLY COME UP TO BANKFULL OR EVEN FLOOD STAGE THROUGH
THE WEEKEND. DESPITE THE CLOUDS/PRECIP/SATURATION...A MILD TURKEY
DAY AHEAD OF THE FRONT WITH HIGHS IN THE MID 50S TO AROUND 60 ACRS
THE SOUTHEAST HALF OF THE FCST AREA...40S TO LOW 50S TO THE WEST OF
THAT UNLESS THE FRONT SLOWS MORE.
THE 12Z RUNS SUGGEST MARGINAL IN-WRAPPING LLVL COLD CONVEYOR AND
EVENTUAL TOP-DOWN COOLING ABOVE THAT PROCESS FOR A PRECIP SWITCH TO
SLEET OR FREEZING RAIN BRIEFLY ACRS THE FAR NORTHWESTERN CWA LATE
THU NIGHT...THEN TO A RAIN-SNOW MIX INTO FRI MORNING. FOR NOW WILL
ADVERTISE LESS THAN AN INCH OF WET SNOW ACCUM BY FRI MORNING
WEST/NORTHWEST OF THE CEDAR RAPIDS AREA. THE LLVLS MAY STAY WARM
ENOUGH FOR ALL RAIN ARRIVAL AT THE SFC ACRS THE EASTERN THIRD OF THE
DVN CWA THU NIGHT INTO FRI AM.
FRIDAY THROUGH SUNDAY...LATEST SUITE OF MEDIUM RANGE MODELS IN MORE
DISAGREEMENT IN HANDLING A SOUTHERN STREAM SYSTEM EJECTING OF OF THE
SOUTHERN PLAINS AND UP TOWARD THE REGION...BATTLING WESTERN GRT LKS
RIDGING AS IT DOES. TAKING A GENERAL ENSEMBLE BLEND...IT SUGGESTS
THAT A PRECIP SHIELD OFF THIS POTENTIAL SYSTEM MAY SPREAD UP ACRS THE
SOUTHERN 2/3S OF THE CWA FROM LATE SAT AND INTO SUNDAY. THE 12Z GFS
IS MILDER WITH IT/S LOW TO MID LEVEL THERMAL PARAMETERS AND SUGGESTS
MAINLY A OVERRUNNING LIGHT TO MODERATE RAIN EVENT ALONG AND SOUTH OF
THE HWY 30 CORRIDOR WITH RAIN ENDING BY LATE SUNDAY MORNING. THE
12Z ECMWF SUGGESTS A WINTRY MIX OF SLEET/FREEZING RAIN...THEN A
SWITCH OVER TO WET SNOW UP ALONG AND NORTH OF THE I80 CORRIDOR SAT
NIGHT...LINGERING LONGER INTO SUNDAY BUT SWITCHING OVER TO MAINLY A
COLD RAIN WITH COLUMN MODERATION ALOFT. WILL GO WITH HIGHER POPS
SOUTH AND ADVERTISE A RAIN-SNOW MIX IN THE NORTH FOR NOW...FURTHER
DEFINING PRECIP TYPES OVER THE NEXT SEVERAL DAYS AS WE GET CLOSER TO
THE PRECIP EVENT. HIGHS IN THE UPPER 30S TO 40S SAT INTO SUNDAY...
WITH LOWS AT NIGHT IN THE 20S TO LOWER 30S POSSIBLY BEING TOO COLD.
EARLY NEXT WEEK...THE MEDIUM RANGE SOLUTIONS STILL SUGGEST A CLOSED
UPPER LOW WITH VARYING THERMAL PROFILES DEPENDING ON THE MODEL...
ROLLING SLOWLY ACRS THE MIDWEST FOR OCCASIONAL PRECIP CHANCES FROM
LATE MONDAY THROUGH AT LEAST TUE NIGHT. ..12..
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z WEDNESDAY EVENING)
ISSUED AT 539 PM CST TUE NOV 24 2015
VFR CONDITIONS WILL PERSIST THIS EVENING. OVERNIGHT... THERE IS
THE POTENTIAL FOR PATCHY TO AREAS OF FOG MAINLY OVER THE SNOW
COVER... WITH GENERALLY NO WORSE THAN MVFR VSBYS WITH VERY LOW
PROBABILITY OF IFR NEAR/NORTH OF HWY 30 INCLUDING KCID AND KDBQ.
HAVE CONTINUED MENTION OF LLWS FROM AROUND 07Z-15Z WITH RAP AND
NAM MODEL SOUNDINGS SHOWING WINDS FROM SSW AROUND 40 KTS
DEVELOPING IN 1000-2000FT AGL RANGE WHILE SFC WINDS REMAIN E/SE
AROUND 10 KTS. LATE TONIGHT AND THROUGH THE MORNING ON WEDNESDAY
WILL SEE STRATUS LIFT UP ACROSS THE TERMINALS WITH INITIALLY VFR
CIGS BUT THEN LOWERING TO MVFR... WITH PATCHY DRIZZLE OR VERY
LIGHT RAIN AT TIMES ESPECIALLY OVER THE RESIDUAL SNOW COVER.
&&
.DVN WATCHES/WARNINGS/ADVISORIES...
IA...NONE.
IL...NONE.
MO...NONE.
&&
$$
SYNOPSIS...HAASE
SHORT TERM...HAASE
LONG TERM...12
AVIATION...MCCLURE
AREA FORECAST DISCUSSION
National Weather Service Dodge City KS
250 AM CST MON NOV 23 2015
...Updated Short and Long Term Discussion...
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 248 AM CST MON NOV 23 2015
A northwesterly flow across the Central Rockies will become more
westerly during the day. This improving westerly flow will result
in a developing trough of low pressure along the lee of the
Rockies and some warming in the 950mb to 850mb level. Based on the
weak net 24 hour warming trend in the 950mb to 850mb level along
with the mixing potential and 00z Tuesday temperatures at this
height the highs today are expected to 3-5F warmer than yesterday.
Tonight the surface winds will be a little stronger than the past
few nights. This combined with increasing low level moisture will
tend towards staying close to the latest MET/MAV guidance.
.LONG TERM...(Tuesday THROUGH Sunday)
ISSUED AT 248 AM CST MON NOV 23 2015
Models remain in good agreement with an upper level storm system
moving from the coast of British Columbia into the western United
States during the first half of the work week. This will result in
the westerly flow across the Central Rockies early in the week
backing to the Southwest by early Wednesday. Subtle upper waves
embedded in this developing southwesterly flow still evident based
on 500mb to 400mb potential vorticity. One of which will be
crossing western Kansas on Wednesday and then a stronger wave on
Thursday. A cold front moving south across the Northern Plains on
Tuesday will extend from eastern Colorado into north central
Kansas by early Wednesday. Ahead of this surface boundary a
southerly flow will continue to draw more humid air northward into
central and portions of western Kansas. Early morning stratus and
fog appears possible south of this front based on model soundings.
At this time the depth of the low level moisture does not appear
deep enough to support drizzle but later shifts may wish to
reevaluate this. By Wednesday evening warm air advection will
begin to improve across western Kansas. Given this lift along
increasing moisture will keep the chance for rain showers and even
a few thunderstorms developing Wednesday night, especially east of
highway 283.
Chance for precipitation will continue on Thursday with the
precipitation type being mainly in the form of liquid early in the
the day as the cold front moves across southwest Kansas. During
the afternoon the colder air moving into western Kansas behind the
cold front will cool that atmosphere enough for the rain to change
over to snow from northwest to southeast. BUFR soundings even
suggest there may be a brief period of freezing rain or sleet
before the change over to snow. Given how far out this event is
will keep precipitation type simple at this time.
On Thursday night the ongoing precipitation will continue early
and then begin to taper off from north to south as a 700mb
baroclinic zone moves across western Kansas. At this time it
appears that the prevailing precipitation type will be snow with
the possible exception of portions of south central Kansas. Upper
level jet dynamics shift north and northeast early and isentropic
downglide observed in the I285 to I295 level by 06z Friday.
Frontogenesis also not that strong near the 700mb baroclinic zone.
The better moisture and lift appears to be focused above the 700mb
level so can not rule out some light snow but accumulations should
be light. Possible exception will be near the OK border,
especially in far southwest Kansas, where up to an inch may not be
completely out of the question.
On Friday any lingering light snow will end, however Friday still
appears to be cloudy and cold as a surface ridge axis begins to
build into western Kansas. Based on 950mb and 850mb temperatures
at 18z Friday and 00z Saturday the previous forecast with highs
only in the 30s still look on track.
On Friday night and Saturday moisture and isentropic lift begins
to improve across western Kansas in the i285 to i300 levels as the
cold dome of high pressure begins to build into western Kansas and
the next upper level wave begins to approach the area from the
southwest. Over parts of western Kansas a southeast upslope flow
is also evident west of the surface ridge axis. Given moisture
return and lift late Friday night into Saturday there will be
improving chances for snow across all of western Kansas early this
weekend. This chance for precipitation will continue through early
Sunday. Some snow accumulations will be possible from this weekend
event, however at how much snow and where is still unclear.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z Monday NIGHT)
ISSUED AT 1145 PM CST SUN NOV 22 2015
VFR conditions are expected overnight and Monday based on BUFR
soundings moisture profiles along with the latest RUC and HRRR.
The winds will be west to southwest at less than 10 knots.
Southwesterly winds on Monday are expected to increase to around
15 knots by the early afternoon as a the weak surface trough axis,
located across eastern Colorado, remains nearly stationary and
deepens.
&&
.PRELIMINARY POINT TEMPS/POPS...
DDC 62 34 60 38 / 0 0 0 0
GCK 63 28 59 31 / 0 0 0 0
EHA 63 31 66 37 / 0 0 0 0
LBL 64 32 63 35 / 0 0 0 0
HYS 62 33 57 37 / 0 0 0 0
P28 64 35 61 47 / 0 0 0 0
&&
.DDC Watches/Warnings/Advisories...
NONE.
&&
$$
SHORT TERM...Burgert
LONG TERM...Burgert
AVIATION...Burgert
AREA FORECAST DISCUSSION
National Weather Service Dodge City KS
1147 PM CST SUN NOV 22 2015
...Updated Synopsis and Aviation discussions...
.SYNOPSIS...
ISSUED AT 1145 PM CST SUN NOV 22 2015
At 00z Monday a 500mb trough extended from the Upper Great Lakes
to the Tennessee Valley. A 500mb ridge axis was located along the
western United states. Over the Central United States a northwest
flow was evident at the 700mb and 500mb level. Across Kansas and
Nebraska earlier this evening 850mb temperatures varied from +3 at
Topeka to +8C at Dodge City and North Platte.
&&
.SHORT TERM...(THIS EVENING THROUGH Monday)
ISSUED AT 316 PM CST SUN NOV 22 2015
Northwest flow aloft will persist through the next couple of days.
Weak westerly surface flow will give way to south winds once again
on Monday as the surface trough develops over eastern Colorado. As
more broad zonal flow develops by Monday night, an initial lead
westerly shortwave will be approaching the region. Models suggest
this will be mainly a dry/ non-precipitation events, with probably
an increase in cloud cover heading into the Tuesday period.
Continually but slightly increasing high temperatures are likely in
the meantime as the boundary layer temperatures rise sue to
adiabatically warmed air from the higher terrain. The snow over
extreme western Hamilton county will likely be eliminated, and highs
could reach the low 60s area wide on Monday. The latest ECMWF model
temperatures have appear to do the best in the medium range and were
generally followed.
.LONG TERM...(Monday NIGHT THROUGH Sunday)
ISSUED AT 316 PM CST SUN NOV 22 2015
The more amplified wave will be on the heels right around the
Thanksgiving travel period. Initially higher surface winds will
likely mean slower warming Tuesday and perhaps slightly cooler
highs. An increase in cirrus clouds should occur by late Tuesday
with the aforementioned shortwave before stronger surface pressure
falls develop ahead of the strong cold front all the models show
by Thanksgiving day. The main problem will be precipitation, how
much and what type. Rain and thunderstorms are possible in the
prefrontal environment as the models indicate modest moisture
transport, but it is possible most of this will be well to the
east in eastern Kansas as well. It is possible our far western
Kansas counties will be on the low end for precipitation
probabilities, but fare better after the frontal passage for
ra/sn. The models indicate another system on its heels by around
saturday, and precipitation probabilities remain in the forecast
through the rest of the extended.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z Monday NIGHT)
ISSUED AT 1145 PM CST SUN NOV 22 2015
VFR conditions are expected overnight and Monday based on BUFR
soundings moisture profiles along with the latest RUC and HRRR.
The winds will be west to southwest at less than 10 knots.
Southwesterly winds on Monday are expected to increase to around
15 knots by the early afternoon as a the weak surface trough axis,
located across eastern Colorado, remains nearly stationary and
deepens.
&&
.PRELIMINARY POINT TEMPS/POPS...
DDC 29 61 33 59 / 0 0 0 0
GCK 26 59 28 56 / 0 0 0 0
EHA 26 60 33 62 / 0 0 0 0
LBL 27 61 32 59 / 0 0 0 0
HYS 28 60 31 55 / 0 0 0 0
P28 30 61 34 59 / 0 0 0 0
&&
.DDC Watches/Warnings/Advisories...
NONE.
&&
$$
SYNOPSIS...Burgert
SHORT TERM...Russell
LONG TERM...Russell
AVIATION...Burgert
AREA FORECAST DISCUSSION
NWS CARIBOU ME
1246 AM EST MON NOV 23 2015
.SYNOPSIS...
LOW PRESSURE WILL DEVELOP ALONG A STATIONARY FRONT EAST OF THE
REGION TONIGHT AND MOVE NORTHEAST MONDAY TOWARD NOVA SCOTIA. HIGH
PRESSURE WILL BUILD TOWARD THE REGION MON NIGHT INTO TUE.
&&
.NEAR TERM /THROUGH TODAY/...
UPDATE 1240 AM: HAVE ADJUSTED TEMPERATURE... DEWPOINT AND WIND. NO
OTHER CHANGES.
SFC LOW CURRENTLY SITTING OFF OF THE VIRGINIA CAPES AND RIDING UP
ALONG FRONTAL BOUNDARY JUST OFFSHORE. FAIRLY TIGHT GRADIENT EXISTS
BTWN PCPN AND NO PCPN AS EXPECTED WITH HUL HVG RAIN AND PQI
NOTHING IN THE WAY OF PCPN. RADAR POPUP SKEW T IS SHOWING HUL
ISOTHERMAL FROM ABOUT 900MB UP WITH BLYR ABV ZERO ALL THE WAY BACK
TO ALLAGASH. THIS AGREES WELL WITH LATEST HRRR DATA THUS HV
ADJUSTED WX GRIDS BASED ON HRRR FCST DATA THRU THE MRNG.
EXPECT THAT PCPN WL BE HIT AND MISS IN NATURE FROM ABOUT PQI
NORTHWARD BUT IF IT CAN GET THIS AFTN NORTH IT SHOULD NOT BEGIN TO
MIX WITH SNOW UNTIL CLOSE TO 03Z. PCPN SHUD GRADUALLY SPREAD NORTH
AFT ABOUT 05Z AS LOW TRACKS CLOSER TO GULF OF MAINE IN COMBINATION
WITH RFQ OF H3 SPEED MAX GETTING EVER CLOSER TO CWA. THIS WL
BRING THE BEST CHC FOR ACCUMULATING SNOW FOR NORTHERN AREAS BFR
DAYBREAK.
AT THIS TIME IT APPEARS THAT QPF AMNTS WL BE LIGHT FOR NRN ZONES
AND WL BE HARD-PRESSED TO SEE MORE THAN AN INCH OF SNOW AND SLEET
FOR AREAS NORTH OF A MILLINOCKET TO HOULTON LINE. THUS WL CONTINUE
WITH MENTION OF AMNTS UP TO AN INCH BY MRNG. FURTHER TO THE SOUTH
HV LOWERED STORM TOTAL SNOW AMNTS BY ARND AN INCH AS IT APPEARS
THAT CLD AIR WL TAKE LONGER TO WRAP IN BHND LOW ESPECIALLY ALONG
THE COAST. HWVR, WL CONT WITH WINTER WX ADVISORY AS STILL
EXPECTING WIDESPREAD 1-4 INCHES ON TOP OF SLEET THAT FALLS. ALL
THIS WL FALL ON ALREADY WET ROADWAYS WHICH WL QUICKLY ICE OVER AS
TEMPS FALL DRG THE DAY TOMORROW. HIGHEST SNOW TOTALS LOOK TO OCCUR
ACRS NRN WASHINGTON CNTY AS WELL AS PARTS OF SE AROOSTOOK CNTY.
PREV DISCUSSION BLO...
LONGER RANGE MODELS HAVE COME INTO BETTER CONSENSUS FOR THIS
AFTN`S FCST UPDATE REGARDING THE COASTAL LOW EVENT MOVG NE FROM
OFF THE MID ATLC STATES TNGT TOWARD THE CNTRL NOVA SCOTIA MON
AFTN. THE 12Z DTMNSTC ECMWF BACKED OFF FROM BEING FURTHER N LIKE
THE PRIOR 00Z ECMWF RUN...BOTH WITH THE PSN OF THE SFC LOW AND
HEAVIER QPF FURTHER N INTO CNTRL AND NRN PTNS OF THE FA. THE
FURTHER SE TRACK OF THE 12Z GFS AND CANGEM MODELS SEEMS TO BE
INITIALLY VERIFYING BASED ON THE TRAJECTORIES OF THE WRN EDGE
OF RADAR REF MOVG INTO THE MID COAST AND DOWNEAST PTNS OF ME LATE
THIS AFTN.
BASED ON THE CURRENT FCST OF THE LOW TRACK...MILD AIR CURRENTLY
OVR THE FA WILL BE REPLACED BY SIG COLDER AIR MOVG E FROM QB AS
THE LOW HELPS ADVECT IT SE INTO OUR FA LATER TNGT INTO MON MORN.
TEMPS WILL FALL FAIRLY QUICKLY...FIRST ACROSS THE NW HLF LATER
THIS EVE THEN SPREADING SE THRU THE REST OF THE FA LATE TNGT INTO
MON MORN...RESULTING IN PRECIP CHGNG FROM RN TO SN NW TO SE ACROSS
THE FA DURG THIS TM...PERHAPS ACCOMPANIED BY A BRIE PD OF SLEET
BASED ON SREF PRECIP TYPES AND FCST SOUNDINGS. THE TRICKY PART OF
THIS FCST WILL BE OVR E CNTRL AND DOWNEAST PTNS OF THE FA WHERE
SIG PRECIP RATES MAY STILL BE GOING ON WHEN TEMPS APCH OR FALL
BELOW FZG...MEANING LCTNS CHGNG TO SNOW LATEST TNGT N OF THE
IMMEDIATE DOWNEAST COAST COULD RECEIVE THE MOST SN DUE TO GREATER
REMAINING QPF LEFT WITH THIS EVENT. SPEAKING OF QPF... STORM TOTAL
QPF WILL RANGE FROM NEAR ZERO OVR THE FAR NW TO NEARLY 2.00 INCHES
OVR THE EXTREME SE. FOR NOW...OUR OFFICIAL MAX SNFL TOTALS ARE 3
TO 5 INCHES OVR NRN AND CNTRL WASHINGTON COUNTIES WITH LESSER
AMOUNTS ELSEWHERE...BUT GIVEN UNCERTAINTIES OF CHGOVR TM AND
POTENTIAL INTENSITY OF SNFL AFT THE CHGOVR...CONFIDENCE WITH MAX
AMOUNTS OVR THIS PTN OF THE FA IS NOT HIGH WITH SIG MORE OR LESS
POSSIBLE. LATER SHIFTS WILL NEED TO MONITOR OBSVD AND MODEL TRENDS
WITH THIS EVENT.
IN ANY EVENT...SN WILL TAPER TO SCT SN SHWRS N AND RN/SN SHWRS
CNTRL AND DOWNEAST MON AFTN AND THEN END BY LATE IN THE DAY. BOTH
LOWS TNGT AND HI TEMPS MON WILL BE COLDER...SPCLY OVR CNTRL AND
DOWNEAST PTNS OF THE FA.
&&
.SHORT TERM /TONIGHT THROUGH WEDNESDAY/...
THE SHORT TERM WILL FEATURE FAIR WEATHER UNDER A BUILDING RIDGE,
THOUGH AT LEAST TUE WILL BE A BIT COOLER THAN NORMAL. AT THE
BEGINNING OF THE SHORT TERM, THE BULK OF THE PRECIP IS EXPECTED TO
HAVE DEPARTED TO THE EAST. HOWEVER, WITH THE BASE OF THE UPR TROF
SWINGING OVER THE AREA MON NIGHT, CAN`T RULE OUT SOME LINGERING
CLOUDS AND A FEW LIGHT SN SHWRS IN THE FAR NRN CWA, AS WAS
REFLECTED IN A FEW MODELS.
BEYOND THAT, HIGH PRESSURE AND RIDGING TUE THRU WED WILL BRING
PARTLY TO MOSTLY SUNNY SKIES TO THE STATE. COLD AIR DRAWN IN
BEHIND THE LOW MON NIGHT AND GOOD RADIATIONAL COOLING WILL SET
THE STAGE FOR SOME OF THE COLDEST TEMPS IN THE CWA THUS FAR THIS
COLD SEASON MON AND TUE NIGHTS.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/...
HIGH PRESSURE WILL GRADUALLY SLIDE OFF THE EAST COAST THURSDAY,
KEEPING CONDITIONS DRY FOR THANKSGIVING DAY. THIS WILL ALSO PLACE
THE REGION UNDER SOUTHWEST FLOW ON THE BACKSIDE OF THE HIGH,
ALLOWING TEMPERATURES TO WARM INTO THE MID AND UPPER 40S. HOWEVER,
LOW PRESSURE MOVING BY TO OUR NORTH WILL SLOWLY DRAG A COLD FRONT
EASTWARD ACROSS THE EASTERN US/CANADA THURSDAY NIGHT THROUGH
FRIDAY. THERE`S SOME DISAGREEMENT AMONGST THE LONGER-RANGE MODELS
ON THE EXACT TIMING OF THIS FRONT AND ITS PRECIPITATION, BUT THE
HIGHEST THREAT FOR FRONTAL PASSAGE LOOKS TO OCCUR SOMETIME LATE
FRIDAY THROUGH SATURDAY. IF THE FRONT HOLDS OFF UNTIL FRIDAY
NIGHT, EXPECT WE`LL SEE VERY MILD TEMPERATURES FOR THE DAY AFTER
THANKSGIVING AS HIGHS TOP OUT IN THE UPPER 40S TO LOWER 50S.
HOWEVER, IF THE FRONT MOVES THROUGH A LITTLE FASTER (SIMILAR TO
THE GFS SOLUTION), NORTHERN MAINE MAY HAVE A COOLER AND WETTER
FRIDAY THAN IS CURRENTLY IN THE FORECAST. REGARDLESS, EXPECT MUCH
COLDER AIR WILL MOVE IN BEHIND THE FRONT. SUNDAY LOOKS TO BE THE
COLDEST DAY OF THE WEEKEND AT THE MOMENT, WITH HIGHS ONLY IN THE
20S IN THE NORTH, AND LOWS IN THE TEENS.
&&
.AVIATION /06Z MONDAY THROUGH FRIDAY/...
NEAR TERM: IFR EXPECTED NEXT 24 HOURS AT MOST TERMINALS IN
RAIN/SNOW. EXCEPTION WILL BE FVE WHERE SITE WILL MOST LIKELY BE
AFFECTED BY IFR CIGS WITH PCPN REMAINING TO THE SOUTH. STILL SOME
QUESTION AS TO HOW MUCH CAR AND PQI WILL SEE WITH REGARD TO PTYPE
AS THEY WILL BE ON NORTHERN EDGE OF PCPN SHIELD. HUL WILL SEE
RA/SN MIX AROUND 03Z THEN OVER TO ALL SNOW AFTER 06Z. BGR CAN BE
EXPECTED TO BE RA/SN AFTER 04Z THEN SWITCHING TO SNOW BY 08Z. BHB
WILL BE LATEST TO SEE CHANGEOVER TO RA/SN BY 09Z AND ALL SNOW
AROUND 10Z. BY 18Z MON BHB, BGR AND HUL WILL SEE IMPROVEMENT TO
VFR CIGS WITH FVE, CAR AND PQI VFR BY 15Z. NW WINDS WILL BE GUSTY
DURING THE DAY AT 15G25KTS.
SHORT TERM: ASIDE FROM THE CHC FOR SOME MVFR CIGS AND ISO SN
SHWRS FOR KFVE BEFORE 09ZTUE, ALL TERMINALS ARE EXPECTED TO HAVE
VFR CIGS AND VIS THROUGH WED EVENING. VFR CONDITIONS WILL THEN
CONTINUE THROUGH FRIDAY, THOUGH MVFR CEILINGS WILL BE POSSIBLE AT
THE NORTHERN TERMINALS FRIDAY AFTERNOON AS A COLD FRONT APPROACHES
FROM THE NORTH.
&&
.MARINE...
NEAR TERM: E TO NE WINDS WILL INCREASE TO SCA CRITERIA FOR THE
INNER BAY/HARBOR MZ THIS EVE AND GALES (IN GUSTS) OVR THE OUTER
MZS LATE TNGT...BACKING TO THE N AS THEY CONTINUE INTO MON. GALES
OVR THE OUTER MZS WILL NEED TO BE TRANSITIONED TO AN SCA LATER MON
AFTN. KEPT CLOSE TO WW3 WV GUIDANCE FOR FCST WV HTS.
SHORT TERM: SCA WIND GUSTS AND SEAS LKLY ONGOING OFFSHORE AT THE
START OF THE SHORT TERM. WILL CONTINUE TUE AM BEFORE GRADUALLY
DIMINISHING TUE PM AS HIGH PRES BUILDS INTO THE AREA.
&&
.CAR WATCHES/WARNINGS/ADVISORIES...
ME...WINTER WEATHER ADVISORY UNTIL 11 AM EST THIS MORNING FOR
MEZ006-011-015.
WINTER WEATHER ADVISORY UNTIL 1 PM EST THIS AFTERNOON FOR
MEZ016-017-029-030-032.
MARINE...SMALL CRAFT ADVISORY UNTIL 1 PM EST THIS AFTERNOON FOR ANZ052.
SMALL CRAFT ADVISORY UNTIL 3 AM EST EARLY THIS MORNING FOR
ANZ050-051.
GALE WARNING UNTIL 1 PM EST THIS AFTERNOON FOR ANZ050-051.
&&
$$
NEAR TERM...MIGNONE
AREA FORECAST DISCUSSION
NWS GRAY ME
1239 AM EST MON NOV 23 2015
.SYNOPSIS...
LOW PRESSURE WILL MOVE NORTHEASTWARD THROUGH THE GULF OF MAINE
TONIGHT ALLOWING FOR SOME RAIN AND SNOW ON THE COASTAL PLAIN. HIGH
PRESSURE WILL BEGIN TO BUILD INTO THE REGION MONDAY MORNING WHILE
LOW PRESSURE TRACKS TO OUR EAST. THE HIGH WILL SHIFT OFFSHORE ON
WEDNESDAY AND A BROAD UPPER LEVEL RIDGE BUILDS OVER NEW ENGLAND.
THIS WILL BRING ABOVE AVERAGE TEMPERATURES THROUGH THE END OF THE
WORK WEEK. HIGH PRESSURE WILL HOLD OFFSHORE THROUGH FRIDAY AND THE
NEXT CHANCE FOR RAIN WILL COME OVER THE WEEKEND POSSIBLY.
&&
.NEAR TERM /UNTIL 6 AM THIS MORNING/...
UPDATE...
COLD AIR CONTINUES TO ADVECT SOUTH AND EASTWARD OVERNIGHT WHILE
HEIGHTS LOWER ALOFT. THIS WILL CONTINUE TO ALLOW THE RA TO CHANGE
TO SN OVERNIGHT. MODERATE SNOW AS FAR SOUTH AS THE GYX OFFICE AS
OF MIDNIGHT ACCORDING TO SOCIAL MEDIA AND TELCON REPORTS.
LATEST HRRR RUN CONTINUES TO SHOW A NICE BAND SETTING UP FROM
COASTAL CUMBERLAND COUNTY AND POINTS NORTHEASTWARD THROUGH THE I95
CORRIDOR AND POINTS TO THE EAST AT 09Z. BEST FOCUS SHIFTS EAST
INTO THE KNOW/WALDO COUNTY AREAS BY 12Z. SOME OF THE FIRST
ACCUMULATING SNOWS OF THE SEASON WILL BE OCCURRING DURING THAT
TIME PERIOD...LEADING TO HAZARDOUS TRAVEL CONDITIONS.
PREV DISC...
11 PM UPDATE: RADAR SHOWS RAIN SHIELD MOVING INTO
COASTAL AND MIDCOAST AREAS AS FORECAST. QUICK PEEK AT LATEST
MODELS SHOW GOOD CONTINUITY FROM PRIOR RUN. COLD AIR WORKING IN
INTO THE LOWER LEVELS OVER THE NEXT SEVERAL HOURS WILL GRADUALLY
CHANGE PTYPE TO SNOW. ONLY MINOR TWEAKS TO TEMPS OTRW NO CHANGES
NEEDED ATTM.
630 PM UPDATE: UPDATED TEMPS BASED ON LATEST OBS DATA. ALSO ADDED
SOME AREAS OF FOG FOR COASTAL AND THE ADJACENT AREAS OF ME/NH FOR
NEXT FEW HOURS BEFORE WINDS WINDS AND INCREASING MIXING IN THOSE
AREAS INCREASE.
PREVIOUS DISCUSSION:
CHALLENGING FORECAST THIS SUNDAY AFTERNOON AS WE/LL BE DEALING
WITH A TIGHT PRECIPITATION GRADIENT OVERNIGHT. A SOUTHERN STREAM
SHORT WAVE TROUGH CURRENTLY EJECTING OFF THE CAROLINA COAST THIS
EVENING WILL MOVE NORTHEAST OVERNIGHT. THIS TROUGH AND ASSOCIATED
SFC LOW PRESSURE WILL COME CLOSE ENOUGH TO THE NEW ENGLAND COAST
TO ALLOW FOR THE SHIELD OF PRECIPITATION TO MOVE INTO THE COASTAL
PLAIN OF MAINE AND NEW HAMPSHIRE. HOWEVER...THE QUESTION IS HOW
FAR WEST...HOW MUCH QPF...AND HOW MUCH WILL FALL AS SNOW?
THE 12Z MODELS AND ENSEMBLES HAVE COME MORE OR LESS INTO GENERAL
AGREEMENT WITH THE WESTERN EXTENT OF THE STRONG FORCING FOR
ASCENT. HOWEVER...SHARP BACK EDGES ARE ALWAYS TRICKY SINCE 5 TO
10 MILES COULD MEAN THE DIFFERENCE BETWEEN NO PRECIPITATION AND UP
TO A HALF INCH LIQUID OR LIQUID EQUIVALENT. USED A CONSENSUS
APPROACH FOR THE OVERNIGHT HOURS...AND GAVE THE LATEST MESOSCALE
MODELS /HRRR AND RAP/ A LITTLE MORE CREDENCE IN THE BLEND. THIS
WAS ALSO THE CASE WITH TIMING OF POPS AS WELL.
AT THE SAME TIME...THE COLUMN AS A WHOLE WILL GRADUALLY GET
COLDER OVERNIGHT...AND THIS INCLUDES A CONTRIBUTION FROM DYNAMIC
COOLING THAT SHOULD OCCUR ONCE THE HEAVIER PRECIPITATION GETS
GOING. SO BLENDING THE ABOVE IDEAS WITH TEMPERATURE AND POP
TRENDS ALONG WITH A CONSENSUS-BASED QPF FORECAST...IT LOOKS AS
THOUGH SOME ACCUMULATING SNOW IS IN THE CARDS TONIGHT FOR THE
COASTAL PLAIN AS WELL AS PORTIONS OF CENTRAL MAINE.
RAIN THIS EVENING SHOULD GRADUALLY FLIP OVER TO WET SNOW AFTER
MIDNIGHT FROM WEST TO EAST AS A COLUMN COOLS. THEREAFTER...IT
DEPENDS ON HOW HARD IT IS PRECIPITATING THAT WILL DETERMINE HOW
MUCH SNOW STICKS. USING OUR CURRENT IDEAS...WE ARE FORECASTING UP
TO AN INCH OF SNOW ON THE MAINE COASTAL PLAIN...WITH 1 TO 3 INCHES
ON THE MID COAST NORTHWARD INTO PARTS OF CENTRAL MAINE. HIGHER
ELEVATIONS NEAR THE MID COAST SUCH AS THE CAMDEN HILLS NORTHWARD
TO THE HILLY SPOTS IN WALDO COUNTY NEAR ROUTES 202 AND 139 COULD
ALSO EXPERIENCE HIGHER AMOUNTS. PERHAPS UP TO 4 INCHES DEPENDING
HOW FAST THE PRECIP CHANGES OVER AND HOW HARD IT FALLS. AT THIS
TIME...SNOW AMOUNTS SHOULD BE MINIMAL ENOUGH TO AVOID WIDESPREAD
POWER OUTAGE PROBLEMS. HOWEVER...ISOLATED OUTAGES WILL BE
POSSIBLE GIVEN THE EXPECTED HEAVY AND WET NATURE TO THE SNOW AFTER
THE CHANGEOVER COMBINED WITH INCREASING NORTHERLY WINDS.
OTHERWISE...FURTHER SOUTH DOWN I-95 INTO
AUGUSTA...LEWISTON...GRAY...AND PORTLAND...UP TO AN INCH WILL BE
POSSIBLE /PERHAPS A LITTLE BIT MORE IN AUGUSTA/WATERVILLE
CORRIDOR/. TEMPERATURES WILL FALL TO NEAR FREEZING IN THESE AREAS
TOWARD MORNING SO IT/S POSSIBLE ANY WET SNOW AND STANDING WATER
COULD FREEZE AND THIS MAY ALLOW FOR SOME SLIPPERY SPOTS FOR THE AM
COMMUTE. IF THE IMPACTS LOOK TO BE A LITTLE MORE SUBSTANTIAL LATER
ON...AN ADVISORY MAY BE ISSUE FURTHER SOUTH. FOR NOW...WE HAVE A
WINTER WEATHER ADVISORY FOR JUST WALDO AND KNOX COUNTY WHERE THE
POTENTIAL FOR ACCUMULATING SNOW IS GREATEST.
&&
.SHORT TERM /6 AM THIS MORNING THROUGH 6 PM TUESDAY/...
ANY SNOW WILL MOVE OUT EARLY MONDAY MORNING...WITH SUNNY SKIES
QUICKLY MOVING IN. OVERALL...COLD TEMPERATURES AND BLUSTERY WINDS
WILL BE THE RULE MONDAY. HIGH PRESSURE MOVES IN MONDAY NIGHT ALLOW
FOR A COLD AND CLEAR NIGHT.
&&
.LONG TERM /TUESDAY NIGHT THROUGH SUNDAY/...
THE MODELS ARE IN GENERAL AGREEMENT ON THE LONG WAVE PATTERN
THROUGH LATE NEXT WEEK. THE UPPER TROUGH ACROSS THE REGION AT THE
START OF THE PERIOD WILL LIFT OUT INTO THE MARITIMES BY
WEDNESDAY...REPLACED BY A BROAD RIDGE AND WEST-SOUTHWEST FLOW
ALOFT...IN RESPONSE TO DIGGING PACIFIC SHORTWAVE ENERGY CARVING
OUT A DEEP TROUGH OVER THE WESTERN CONUS. BY FRIDAY...SIGNIFICANT
DIFFERENCES EMERGE IN NUMERICALS WITH GFS MOST PROGRESSIVE WITH
HANDLING OF WESTERN TROUGH...WITH SLOWER ECMWF/CMC-GLOBAL
SCENARIO REMAINING THE PREFERRED SOLUTION FOR NOW.
IN THE DAILIES...A FEW CLOUDS TUESDAY AS THE UPPER TROUGH SWINGS
ACROSS THE AREA. RISING HEIGHTS WITH HIGH PRESSURE AND DRY AIR
BRINGS MODERATING TEMPERATURES FOR WEDNESDAY AND THURSDAY. THE
PREFERRED AND SLOWER ECMWF/CMC-GLOBAL SOLUTIONS KEEP THE RIDGE
ACROSS THE AREA AND THE APPROACHING FRONTAL SYSTEM WELL TO OUR
WEST ON FRIDAY. THE COLD FRONT SHOULD CROSS THE AREA ON SATURDAY...WITH
SHARPLY COLDER TEMPERATURES AND SOME UPSLOPE SNOW SHOWERS IN ITS
WAKE TO ROUND OUT NEXT WEEKEND.
&&
.AVIATION /06Z MONDAY THROUGH FRIDAY/...
SHORT TERM...MVFR TO IFR CONDITIONS ARE PROBABLE TONIGHT ON THE
COASTAL PLAIN WHERE RAIN CHANGING TO SNOW IS LIKELY. VFR
CONDITIONS RESUME MONDAY MORNING AND CONTINUE THROUGH MONDAY
NIGHT. GUSTY NORTHWESTERLY WINDS TO 25 KT WILL BE LIKELY LATE
TONIGHT AND MONDAY.
LONG TERM...
NO SIGNIFICANT OPERATIONAL IMPACTS DUE TO WEATHER EXPECTED.
&&
.MARINE...
SHORT TERM...SMALL CRAFT ADVISORIES HAVE BEEN HOISTED FOR TONIGHT
THROUGH MONDAY. NOT OUT OF THE QUESTION THESE WILL NEED TO BE
UPGRADED TO GALES FOR A TIME LATE TONIGHT INTO MONDAY. WINDS AND
SEAS DIMINISH MONDAY NIGHT.
LONG TERM...
THU - FRI...SMALL CRAFT WINDS AND SEAS ARE POSSIBLE WITH GUSTS
TO NEAR GALE OUTSIDE THE BAYS.
&&
.GYX WATCHES/WARNINGS/ADVISORIES...
ME...WINTER WEATHER ADVISORY UNTIL 8 AM EST THIS MORNING FOR MEZ022-
027-028.
NH...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 2 AM EST TUESDAY FOR ANZ150>154.
&&
$$
JC
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
725 PM EST TUE NOV 24 2015
.SHORT TERM...(THIS EVENING THROUGH WEDNESDAY)
ISSUED AT 332 PM EST TUE NOV 24 2015
12Z RAOBS/LATEST WV IMAGERY AND RAP ANALYSIS SHOW AN UPR RDG OVER
THE PLAINS EXPANDING INTO THE GREAT LKS. 00Z-12Z H5 HGT RISES OVER
MUCH OF THE W HALF OF THE GREAT LKS WERE AOA 100M AND AS MUCH AS
130M AT APX AND DTX. THE 12Z INL/GRB/APX RAOBS SHOW SHARP SUBSIDENCE
INVRN IN THE H8-85 LYR. DESPITE TEMPS AT THIS ELEVATED INVRN BASE AS
LO AS -10C...RATHER DRY NATURE OF THE SUB INVRN LYR AS DEPICTED ON
THE INL AND GRB RAOBS HAS GREATLY RESTRICTED LES EVEN OVER THE E...
WHERE THE LLVL NW FLOW WAS WEAKLY CYC THIS MRNG AHEAD OF A WEAK SFC
RDG AXIS OVER THE WRN CWA EXTENDING TO THE N OF STRONGER HI CENTER
IN THE TN RIVER VALLEY. THE LO CLDS HAVE BROKEN UP SOMEWHAT WITH THE
ARRIVAL OF THE SFC RDG OVER THE W AND SCENTRAL. EVEN WHERE THE LO
CLDS HAVE DSPTD...A GOOD AMOUNT OF MID/UPR LVL MSTR ASSOCIATED WITH
STRONGER WAA IN THE NRN PLAINS IS SUPPORTING AREA OF MID/HI CLDS
SPILLING OVER THE RDG INTO THE WRN LKS.
MAIN FCST CONCERNS IN THE SHORT TERM FOCUS ON THE IMPACT OF
STRENGTHENING SLY FLOW THAT IS FCST TO DEVELOP TNGT/WED BETWEEN SFC
HI PRES RDG FCST TO MOVE E/BUILD UNDER THE EXPANDING UPR RDG AND
FALLING MSLP IN THE PLAINS TO THE E OF A DEEPENING TROF OVER THE W.
TNGT...SFC HI PRES SHIFTING E INTO NEW ENGLAND/MID ATLANTIC STATES
IS FCST TO BUILD TO ABOUT 1040MB BY 12Z WED. IN CONCERT WITH DVLPG
LO PRES TROF ALONG THE BORDER BTWN MN AND THE DAKOTAS...THE PRES
GRADIENT OVER THE WRN GREAT LKS IS FCST TO TIGHTEN CONSIDERABLY...
WITH S H925 WINDS INCRSG UP TO 35-40KTS ACCENTUATED BY DVLPG PRES
FALL CENTER OVER NW ONTARIO. MODELS SHOW AN AXIS OF HIER RH IN THE
SFC-H9 LYR RETURNING INTO THE CENTRAL CWA OVERNGT WITHIN THIS
STRENGTHENING SLY FLOW AND UNDER LINGERING LARGER SCALE SUBSIDENCE
INVRN. WITH AN UPSOPE LLVL SSE FLOW... MAINTAINED SOME FCST -DZ/
-FZDZ IN THIS AREA. LIMITED DEPTH OF RETURNING MOIST LYR AND/OR
DOWNSLOPE FLOW WL RESULT IN A DRY FCST FOR THE REST OF THE CWA. LO
TEMPS MAY BE TRICKY TNGT...ESPECIALLY OVER THE E. IF THE LO CLDS
LINGERING THERE DSPT THIS EVNG WITH THE PASSING OF THE SFC HI/MORE
ACYC FLOW BEFORE THE SLY FLOW PICKS UP...TEMPS COULD FALL QUICKLY
BEFORE WINDS PICK UP OVERNGT. SUSPECT THE LO CLDS WL BE RESILIENT
ENUF AND INCOMING MID/HI CLDS WL LIMIT THIS EVNG TEMP DROP...SO DID
NOT GO TOO LO WITH FCST MIN TEMPS. INCRSG S WINDS/MORE CLDS WL
LIKELY BRING RISING TEMPS OVERNGT.
WED...STEADY/GUSTY S SLOWLY VEERING SW LLVL FLOW IS FCST TO SLOWLY
INCRS MSTR DEPTH THRU THE DAY. IN CONCERT WITH SOME WEAK DEEP LYR
QVECTOR CNVGC ASSOCIATED WITH THE LARGER SCALE WAA/ISENTROPIC
ASCENT...THERE MAY BE SOME LIGHT RA OR DZ. BUT GENERAL DRYNESS OF
THE FCST AIRMASS IN THE MID LVLS/DGZ AND ONLY WEAK FORCING SUGGESTS
ANY PCPN WL BE ON THE LGT SIDE. SO MODEL QPF IS RATHER LGT AND
SPOTTY AND FOCUSED MAINLY AWAY FM THE DOWNSLOPE AREAS NEAR LK SUP.
ALTHOUGH THE CLDS WL HOLD DOWN MAX TEMPS...READINGS NOT FAR FM 40 WL
STILL BE WELL ABOVE NORMAL.
.LONG TERM...(WEDNESDAY NIGHT THROUGH TUESDAY)
ISSUED AT 416 PM EST TUE NOV 24 2015
BY 00Z THURSDAY THE INITIAL N END OF THE ELONGATED SFC TROUGH WILL
BE SET UP FROM N ONTARIO THROUGH THE W HALF OF LAKE
SUPERIOR...EXTENDING IN THE FORM OF A COLD FRONT DOWN THROUGH KS TO
THE S LOW OVER NE NM. THE NAM IS HINTING AT SOME ENHANCEMENT TO THE
PRECIP ACROSS THE N CENTRAL HIGHER TERRAIN AREAS FROM BIG BAY
THROUGH NEGAUNEE/ISHPEMING TO GWINN WEDNESDAY EVENING.
THE N END OF THE BROAD 500MBTROUGH STRETCHING FROM N CENTRAL CANADA
DOWN TO THE MAIN LOW MOVING ON SHORE IN OR/N CA THIS AFTERNOON WILL
KEEP A CUT OFF LOW SPINNING OVER THE W THIRD OF THE NATION THROUGH AT
LEAST THE FIRST HALF OF THE UPCOMING WEEKEND.
LOOK FOR THE COLD FRONT TO SWEEP TO THE E HALF OF UPPER MI BY
DAYBREAK THURSDAY. AS THE N END OF THE 500MB TROUGH SHIFTS ACROSS
MANITOBA TO E MT. WILL KEEP THE FREEZING DRIZZLE/DRIZZLE POTENTIAL
GOING OVERNIGHT WEDNESDAY NIGHT THROUGH THURSDAY MORNING...BEFORE
BETTER MOISTURE SNEAKS IN. THURSDAY AFTERNOON AND EVENING WILL BE
THE LARGEST THREAT PERIOD FOR MAINLY CENTRAL AND E UPPER MI...WITH A
SMALL CHANCE OF SLEEP S CENTRAL THURSDAY AFTERNOON INTO THE
EARLY EVENING HOURS. ELSEWHERE...SNOW SHOULD BE ON THE
DOORSTEP...CHANGING OVER TO ALL SNOW W THURSDAY MORNING AND HOLDING
OFF FAR E UNTIL THURSDAY EVENING. THE CANADIAN AND ECMWF ARE STILL
MORE ROBUST ON THE W PRECIP PUSH. THE OVERALL PICTURE IS
SIMILAR...MAKING THE FCST TRICKY. THE 12Z ECMWF DID COME IN WITH A
LITTLE LESS PRECIP THOUGH OVER CENTRAL UPPER MI...IN SOME PLACES
CLOSE TO 0.2IN LESS. A BLENDED SOLUTION STILL LOOKS GOOD...WITH A
SLANT TOWARDS THE ECMWF SOLUTION AS IT BEGINS TO COME MORE IN LINE
WITH THE GFS.
THE 500MB TROUGH AND COLDEST 850MB TEMPS OF -5 TO -8C TRAVERSES
UPPER MI FRIDAY...WITH THE GFS STILL THE MOST PROGRESSIVE. THE
FAVORABLE N-NNW SNOW WINDS OFF LAKE SUPERIOR SLOWLY SWITCH TO A MORE
W DIRECTION LATER FRIDAY WITH SNOW ENDING W TO E AS HIGH PRESSURE
BUILDS INTO THE REGION.
THE LARGE 500MB LOW OVER THE W U.S. BEGINS TO SHIFT ACROSS THE N AND
CENTRAL PLAINS LATE SUNDAY THROUGH MONDAY...BEFORE MOVING TO THE
UPPER GREAT LAKES TUESDAY. THE GFS IS MORE PROGRESSIVE THAN THE
ECMWF...WITH A NEARLY STACKED SFC-500MB LOW SPINNING ACROSS THE N/WI
BORDER BY 12Z TUESDAY. THE 00Z ECMWF SOLUTION WAS MORE WRAPPED UP
BUT WITH LESS MOISTURE AVAILABLE AND A WEAKER SFC REFLECTION. THE
SFC HIGH REMAINED STRONG OVER THE REGION THROUGH...WITH 12-24 HOUR
SLOWER RESPONSE COMPARED TO THE GFS. THE 12Z ECMWF CAME IN MUCH MORE
IN LINE WITH THE 12Z GFS WITH THE NEXT SFC LOW OVERHEAD AT 12Z
MONDAY. WILL SEE IF THIS BETTER CONSISTENCY CAN HOLD UP THROUGH THE
NEXT COUPLE OF DAYS.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z WEDNESDAY EVENING)
ISSUED AT 718 PM EST TUE NOV 24 2015
AN INCREASING S WIND TONIGHT WILL RESULT IN IN LLWS OVERNIGT AND
DRAW MOISTER AIR INTO THE WESTERN GREAT LAKES...RESULTING IN
DETERIORATING CONDITIONS IN THE PRESENCE OF NOCTURNAL COOLING. THE
BEST CHANCE FOR A SUSTAINED PERIOD OF IFR TO PERHAPS LIFR CONDITIONS
WILL BE AT KSAW...WHERE THE EXPECTED SSE WIND WILL UPSLOPE.
DOWNSLOPE NATURE OF THE EXPECTED FLOW AT KIWD AND KCMX MAKE IFR CIGS
LESS LIKELY. THERE MAY BE SOME IMPROVEMENT LATER WED MORNING WITH
SOME DAYTIME WARMING ALONG WITH GUSTY WINDS AT THE MORE EXPOSED KIWD
AND KSAW LOCATIONS.
&&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 332 PM EST TUE NOV 24 2015
RELATIVELY LIGHT WINDS THIS EVENING WILL BECOME S AND INCREASE
QUICKLY OVERNIGHT UNDER TIGHTENING PRES GRADIENT BETWEEN BUILDING HI
PRES TO THE E AND FALLING PRES IN THE PLAINS. OPTED TO UPGRADE GALE
WATCH FOR MUCH OF THE E HALF TO A WARNING FOR WED INTO THE
EVENING...WHEN THE GRADIENT/WINDS WILL DIMINISH SUFFICIENTLY. EXPECT
A WIND SHIFT TO THE NNW AFTER A COLD FRONT CROSSES THE LAKE ON WED
NIGHT INTO EARLY THU. THE TIGHT PRES GRADIENT AHEAD OF TRAILING HI
PRES WILL LEAD TO WINDS UP TO 30 KTS AND PERHAPS SOME MARGINAL GALE
FORCE WINDS INTO THU NIGHT. WINDS WILL THEN SLOWLY DIMINISH INTO FRI
AS THIS HI PRES EDGES CLOSER. ALTHOUGH W WINDS COULD INCREASE UP TO
25-30KT AGAIN ON SAT UNDER A TIGHTENING GRADIENT BETWEEN THE HI
CENTERED JUST TO THE SW AND ANOTHER LO PRES TROF SWINGING THRU
NORTHERN ONTARIO...A WEAKER GRADIENT AND LIGHTER WINDS ARE EXPECTED
TO PREVAIL ON SUN AFTER THE TROF EXITS INTO QUEBEC AND THE HI PRES
RIDGE BUILDS BACK TOWARD THE UPPER LAKES.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
GALE WARNING FROM 7 AM TO 10 PM EST WEDNESDAY FOR LSZ266-267.
LAKE MICHIGAN...
GALE WARNING FROM 10 AM WEDNESDAY TO 1 AM EST THURSDAY FOR
LMZ248-250.
&&
$$
SHORT TERM...KC
LONG TERM...KF
AVIATION...JLB
MARINE...KC
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
1220 PM EST MON NOV 23 2015
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 450 AM EST MON NOV 23 2015
WATER VAPOR IMAGERY AND RAP ANALYSIS SHOW A TROF EXTENDING S THRU
THE GREAT LAKES REGION. SHEARED OUT SHORTWAVE/LEFT EXIT OF 120+KT
UPPER JET EXTENDING FROM SASKATCHEWAN INTO THE UPPER MISSISSIPPI
VALLEY HAS GENERATED SOME AREAS OF -SN INTO WRN UPPER MI OVERNIGHT.
MODELS OVER THE LAST DAY OF RUNS CORRECTLY TRENDED LIGHTER WITH THIS
PCPN AS SNOW THAT HAS OCCURRED HAS BEEN VERY LIGHT WITH NOT MUCH
MORE THAN A DUSTING OF ACCUMULATION WHERE SNOW HAS FALLEN PER
WEBCAMS. TO THE E...JUST AS SOME HIGH RES MODELS WERE INDICATING 24
HRS AGO...THE REGIONAL CANADIAN IN PARTICULAR...A BURST OF HVY SNOW
MOVED N OFF NRN LAKE MI INTO PARTS OF THE ERN U.P. OVER THE LAST
SEVERAL HRS. IT APPEARS THE EXTREME SE CORNER OF LUCE COUNTY
PROBABLY SAW A VERY BRIEF PERIOD OF MDT TO HVY SNOW AROUND 06Z. THAT
AREA OF MDT/HVY SNOW HAS SHIFTED E INTO THE STRAITS VCNTY SINCE
THEN.
THERE IS STILL SOME CONCERN FOR LAKE ENHANCED SNOW OFF NRN LAKE MI
TO SHIFT/REFORM BACK TO THE W TODAY. ON THE HIGH EXTREME IS THE
REGIONAL CANADIAN WHICH GENERATES 0.3 INCHES OF QPF IN THE FAR SE
CORNER OF LUCE COUNTY BTWN 15Z AND 00Z. SINCE THE MAJORITY OF AVBL
HIGH RES GUIDANCE...INCLUDING THE HIGH RES CANADIAN...KEEPS THE BULK
OF REDEVELOPING LAKE ENHANCED SNOW JUST E OF LUCE COUNTY...WILL KEEP
SNOW AMOUNTS UNDER ADVY CRITERIA WITH PERHAPS 1.5-2 INCHES TO THE SE
OF KERY. ELSEWHERE....PATCHY -SN MOVING ACROSS WRN UPPER MI ATTM
SHOULD DISSIPATE OVER THE NEXT SEVERAL HRS AS IT SHIFTS E AND HAS TO
OVERCOME INITIAL DRY LOWER LEVEL AIR. THEN...A SFC LOW PRES TROF
WILL SWING INTO WRN UPPER MI LATE MORNING/AFTN...BRINGING A WIND
SHIFT TO THE W TO NW. EXPECT -SHSN TO ACCOMPANY THE TROF AS OVERLAKE
INSTABILITY WITH 850MB TEMPS AROUND -7C WILL BE MORE THAN SUFFICIENT
TO GENERATE -SHSN ALONG THE TROF/CONVERGENCE ZONE AS IT CROSSES WRN
LAKE SUPERIOR. THIS WILL THEN TRANSITION TO SCT LAKE EFFECT
-SHSN INTO TONIGHT FOR AREAS FAVORED BY NW WINDS AS 850MB TEMPS DROP
A DEGREE OR TWO C. INITIALLY...INVERSION IS UP AROUND 7KFT THIS
EVENING...BUT FALLS TO AROUND 4KFT W OVERNIGHT AND TO AROUND 5KFT E
LATE. DESPITE THE DECENTLY HIGH INVERSION HEIGHTS...SNOW
ACCUMULATIONS WILL BE LIMITED DUE TO THE DGZ BEING ABOVE THE
CONVECTIVE LAYER. AT THIS POINT...EXPECT ACCUMULATIONS MOSTLY UNDER
1 INCH...BUT IF ANY RELATIVELY STATIONARY BANDS SET UP...THERE
CERTAINLY COULD BE ISOLATED 2-3 INCH AMOUNTS.
.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 422 AM EST MON NOV 23 2015
...RAIN CHANGING TO SNOW WED NIGHT INTO THANKSGIVING DAY WITH
ACCUMULATING SNOW POSSIBLE INTO THU NIGHT...
IN LARGER SCALE...DEEP TROUGH OVER EASTERN CONUS SLIDES TO EASTERN
CANADA ON TUE WHILE SPLIT FLOW TROUGHING DEVELOPS WESTERN CANADA TO
WESTERN CONUS. 1000-850MB TROUGH FORMING ON TUE OVER ROCKIES AND
ADJACENT PLAINS AND LOW-LEVEL HIGH PRESSURE SETTLING TO SOUTHEAST
CONUS WILL ALLOW S/SE WINDS AT SFC TO BRING INCREASING MOISTURE OFF
THE GULF OF MEXICO TOWARD THE MIDDLE MISSISSIPPI RIVER VALLEY. WILL
STAY DRY OVER UPR LAKES ON TUE BUT LATE TUE NIGHT INTO WED MORNING
SOUNDINGS SHOW INCREASING MOISTURE BLO H9 INTO UPPER GREAT LAKES.
IF THERE IS ANY PRECIP AROUND ON WED MORNING...IT LIKELY WOULD TAKE
FORM OF DZ/FZDZ DEPENDING ON SFC TEMPS. BEST CHANCE FOR LIGHT ICING
WOULD BE OVER INTERIOR CNTRL CWA FM IRON/DICKINSON INTO BARAGA AND
WESTERN MARQUETTE COUNTY. MODELS SOMETIMES ARE TOO OVERDONE ON THIS
TYPE OF LOW-LEVEL MOISTENING BUT IN THIS CASE THERE IS DECENT SNOW
PACK JUST TO THE SOUTH SO THAT MAY HELP THE EXPANSION OF LOW-LEVEL
MOISTURE.
LATER ON WEDNESDAY DEEPER MOISTURE AND LARGER SCALE FORCING INCREASE
STEADILY AHEAD OF SHORTWAVE TROUGH SLIDING OVER MANTIOBA AND
NORTHERN ONTARIO. LOW-LEVEL THETA-E ADVECTION INCREASES BRIEFLY
BEFORE BEING SHUNTED TO THE SOUTH AND EAST ON WED NIGHT. SHOULD SEE
LIGHT RAIN BECOME MORE WIDESPREAD...BUT WITHOUT MUCH OF STRONG
MOISTURE TAP AHEAD OF THE TROUGH WITH THE NORTHERN STREAM SHORTWAVE
TROUGH...RAINFALL AMOUNTS SHOULD BE LIGHT. COOLER AIR WITH H85 TEMPS
DOWN BLO -2C SLIDES IN AFTER MIDNIGHT WED NIGHT OVER THE WEST AND
THAT SHOULD TURN ANY LINGERING RAIN TO SNOW. GFS SOUNDINGS AND H85-
H7 RH FIELDS FM THE ECMWF INDICATE MID-LEVEL DRYING MAY LEAD TO
CHANCES OF FREEZING DRIZZLE OR DRIZZLE INSTEAD OF SNOW LATE WED
NIGHT INTO THANKSGIVING MORNING WITH MOIST LAYER AT TEMPS BLO 0C BUT
MUCH WARMER THAN -10C. UPSLOPE FLOW OFF LK SUPERIOR WOULD ALSO AID
IN LOW-LEVEL LIFT AND MAYBE LEAD TO GREATER CHANCES OF DRIZZLE FOR
WEST AND NCNTRL UPR MICHIGAN. ADDED MENTION OF DZ/FZDZ IN THE GRIDS
FOR THESE AREAS.
ATTN LATER ON THANKSGIVING TURNS TO WAVE OF LOW PRESSURE THAT RIDES
NORTHEAST ALONG THE TROUGH OVER THE UPR GREAT LAKES. 00Z ECMWF
TRENDED FARTHER WEST WITH THE WAVE WHILE THE GFS TRENDED FARTHER
EAST. IF THE ECMWF IS CORRECT SWATH OF MODERATE PRECIP WOULD LIFT
BACK OVER AT LEAST THE SOUTH AND EAST CWA THANKSGIVING AFTN INTO
THU NIGHT. SINCE THE INITIAL TROUGH/COLD FRONT IS THROUGH MOST CWA
PTYPE WOULD MOSTLY BE SNOW...EXCEPT OVER FAR SCNTRL WHERE WARM AIR
LINGERS AS EVEN ECMWF SHOWS H85 TEMPS AT LEAST +1C WHEN HEAVIER QPF
IS FORECAST TO MOVE THROUGH. SFC TEMPS STILL MID 30S AS WELL SO NO
RISK OF ANY FREEZING PRECIP EITHER. JUST INLAND OVER SOUTH CENTRAL
AND OVER MOST OF THE EASTERN CWA /N WINDS LEADING TO OFFSHORE WINDS
AT ESC AND ISQ/ COULD SEE SEVERAL INCHES OF WET SNOW WITH THE ECMWF
SOLN AS 12 HR QPF BTWN 18Z THU AND 06Z FRI IS AT LEAST 0.5 IF NOT UP
TO 0.75 INCH. MEANWHILE...LATEST GFS BARELY IS OVER 0.25 INCHES FOR
THAT TIME FRAME. GEM IS MORE LIKE THE ECMWF WITH TOTAL QPF...BUT MUCH
WARMER AND WOULD RESULT IN MOSTLY RAIN FOR THOSE AREAS. WPC PREFERRED
CONSENSUS OF GFS/ECMWF/GEM. WILL CONTINUE TO MENTION THE RAIN TO SNOW
AND SOME ACCUMULATING SNOW IN THE HWO...BUT CANNOT PLAY UP THE SNOW
TOO MUCH OR GET TOO SPECIFIC YET GIVEN THE UNCERTAINTIES THAT REMAIN.
BEHIND THIS SYSTEM...TURNS COLD ENOUGH FOR LAKE EFFECT SNOW SHOWERS
OFF LK SUPERIOR FRI INTO FRI NIGHT. ON FRI...AREAS FAVORED BY N
WINDS MAY SEE SOME SNOW FOR A CHANGE...THEN WOULD BE MAINLY NW FLOW
AREAS FRI NIGHT. DRY LOW-LEVEL AIRMASS WITH STRONG HIGH BUILDING IN
SHOULD LIMIT EXTENT OF LES. BASED ON CURRENT MODEL SOLUTIONS IT IS
DOUBTFUL AMOUNTS WOULD REACH ADVY LEVELS FRI-FRI NIGHT. SLIGHT
WARMING TREND WITH GENERALLY DRY WEATHER IS EXPECTED FOR NEXT
WEEKEND.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON)
ISSUED AT 1220 PM EST MON NOV 23 2015
WITH THE PASSAGE OF A SFC TROF...LAKE EFFECT -SHSN WILL DEVELOP FOR
AREAS FAVORED BY NW WINDS THIS AFTN AND TONIGHT. FOR
KCMX/KIWD...THIS MEANS MVFR CONDITIONS SHOULD PREVAIL THRU THE FCST
PERIOD. AT KSAW...VFR CONDITIONS SHOULD CONTINUE INTO THE MID AFTN
WITH A DOWNSLOPE WESTERLY WIND. MVFR CONDITIONS SHOULD THEN DEVELOP
AT KSAW LATE AFTN AND CONTINUE THRU TUE MORNING.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 450 AM EST MON NOV 23 2015
NO GALES ARE EXPECTED ON LAKE SUPERIOR THRU THE END OF THE WEEK.
PREVIOUSLY...THERE WERE INDICATIONS OF A GALE EVENT THU NIGHT/FRI
AFTER A COLD FRONT PASSES. HOWEVER...IT NOW APPEARS THAT THE FRONT
WILL BE WEAKER SO THAT WINDS WILL REMAIN BLO GALE FORCE. LIGHTEST
WINDS THIS WEEK WILL OCCUR TUE AS A HIGH PRES RIDGE QUICKLY SHIFTS
ACROSS THE UPPER GREAT LAKES. STRONGEST WINDS THIS WEEK WILL OCCUR
LATE TUE NIGHT/WED OVER THE E HALF OF LAKE SUPERIOR IN THE SOUTHERLY
FLOW AHEAD OF THE AFOREMENTIONED COLD FRONT AND THEN LATE THU/FRI
AFTER THE FRONT PASSES.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...ROLFSON
LONG TERM...JLA
AVIATION...07
MARINE...ROLFSON
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
646 AM EST MON NOV 23 2015
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 450 AM EST MON NOV 23 2015
WATER VAPOR IMAGERY AND RAP ANALYSIS SHOW A TROF EXTENDING S THRU
THE GREAT LAKES REGION. SHEARED OUT SHORTWAVE/LEFT EXIT OF 120+KT
UPPER JET EXTENDING FROM SASKATCHEWAN INTO THE UPPER MISSISSIPPI
VALLEY HAS GENERATED SOME AREAS OF -SN INTO WRN UPPER MI OVERNIGHT.
MODELS OVER THE LAST DAY OF RUNS CORRECTLY TRENDED LIGHTER WITH THIS
PCPN AS SNOW THAT HAS OCCURRED HAS BEEN VERY LIGHT WITH NOT MUCH
MORE THAN A DUSTING OF ACCUMULATION WHERE SNOW HAS FALLEN PER
WEBCAMS. TO THE E...JUST AS SOME HIGH RES MODELS WERE INDICATING 24
HRS AGO...THE REGIONAL CANADIAN IN PARTICULAR...A BURST OF HVY SNOW
MOVED N OFF NRN LAKE MI INTO PARTS OF THE ERN U.P. OVER THE LAST
SEVERAL HRS. IT APPEARS THE EXTREME SE CORNER OF LUCE COUNTY
PROBABLY SAW A VERY BRIEF PERIOD OF MDT TO HVY SNOW AROUND 06Z. THAT
AREA OF MDT/HVY SNOW HAS SHIFTED E INTO THE STRAITS VCNTY SINCE
THEN.
THERE IS STILL SOME CONCERN FOR LAKE ENHANCED SNOW OFF NRN LAKE MI
TO SHIFT/REFORM BACK TO THE W TODAY. ON THE HIGH EXTREME IS THE
REGIONAL CANADIAN WHICH GENERATES 0.3 INCHES OF QPF IN THE FAR SE
CORNER OF LUCE COUNTY BTWN 15Z AND 00Z. SINCE THE MAJORITY OF AVBL
HIGH RES GUIDANCE...INCLUDING THE HIGH RES CANADIAN...KEEPS THE BULK
OF REDEVELOPING LAKE ENHANCED SNOW JUST E OF LUCE COUNTY...WILL KEEP
SNOW AMOUNTS UNDER ADVY CRITERIA WITH PERHAPS 1.5-2 INCHES TO THE SE
OF KERY. ELSEWHERE....PATCHY -SN MOVING ACROSS WRN UPPER MI ATTM
SHOULD DISSIPATE OVER THE NEXT SEVERAL HRS AS IT SHIFTS E AND HAS TO
OVERCOME INITIAL DRY LOWER LEVEL AIR. THEN...A SFC LOW PRES TROF
WILL SWING INTO WRN UPPER MI LATE MORNING/AFTN...BRINGING A WIND
SHIFT TO THE W TO NW. EXPECT -SHSN TO ACCOMPANY THE TROF AS OVERLAKE
INSTABILITY WITH 850MB TEMPS AROUND -7C WILL BE MORE THAN SUFFICIENT
TO GENERATE -SHSN ALONG THE TROF/CONVERGENCE ZONE AS IT CROSSES WRN
LAKE SUPERIOR. THIS WILL THEN TRANSITION TO SCT LAKE EFFECT
-SHSN INTO TONIGHT FOR AREAS FAVORED BY NW WINDS AS 850MB TEMPS DROP
A DEGREE OR TWO C. INITIALLY...INVERSION IS UP AROUND 7KFT THIS
EVENING...BUT FALLS TO AROUND 4KFT W OVERNIGHT AND TO AROUND 5KFT E
LATE. DESPITE THE DECENTLY HIGH INVERSION HEIGHTS...SNOW
ACCUMULATIONS WILL BE LIMITED DUE TO THE DGZ BEING ABOVE THE
CONVECTIVE LAYER. AT THIS POINT...EXPECT ACCUMULATIONS MOSTLY UNDER
1 INCH...BUT IF ANY RELATIVELY STATIONARY BANDS SET UP...THERE
CERTAINLY COULD BE ISOLATED 2-3 INCH AMOUNTS.
.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 422 AM EST MON NOV 23 2015
...RAIN CHANGING TO SNOW WED NIGHT INTO THANKSGIVING DAY WITH
ACCUMULATING SNOW POSSIBLE INTO THU NIGHT...
IN LARGER SCALE...DEEP TROUGH OVER EASTERN CONUS SLIDES TO EASTERN
CANADA ON TUE WHILE SPLIT FLOW TROUGHING DEVELOPS WESTERN CANADA TO
WESTERN CONUS. 1000-850MB TROUGH FORMING ON TUE OVER ROCKIES AND
ADJACENT PLAINS AND LOW-LEVEL HIGH PRESSURE SETTLING TO SOUTHEAST
CONUS WILL ALLOW S/SE WINDS AT SFC TO BRING INCREASING MOISTURE OFF
THE GULF OF MEXICO TOWARD THE MIDDLE MISSISSIPPI RIVER VALLEY. WILL
STAY DRY OVER UPR LAKES ON TUE BUT LATE TUE NIGHT INTO WED MORNING
SOUNDINGS SHOW INCREASING MOISTURE BLO H9 INTO UPPER GREAT LAKES.
IF THERE IS ANY PRECIP AROUND ON WED MORNING...IT LIKELY WOULD TAKE
FORM OF DZ/FZDZ DEPENDING ON SFC TEMPS. BEST CHANCE FOR LIGHT ICING
WOULD BE OVER INTERIOR CNTRL CWA FM IRON/DICKINSON INTO BARAGA AND
WESTERN MARQUETTE COUNTY. MODELS SOMETIMES ARE TOO OVERDONE ON THIS
TYPE OF LOW-LEVEL MOISTENING BUT IN THIS CASE THERE IS DECENT SNOW
PACK JUST TO THE SOUTH SO THAT MAY HELP THE EXPANSION OF LOW-LEVEL
MOISTURE.
LATER ON WEDNESDAY DEEPER MOISTURE AND LARGER SCALE FORCING INCREASE
STEADILY AHEAD OF SHORTWAVE TROUGH SLIDING OVER MANTIOBA AND
NORTHERN ONTARIO. LOW-LEVEL THETA-E ADVECTION INCREASES BRIEFLY
BEFORE BEING SHUNTED TO THE SOUTH AND EAST ON WED NIGHT. SHOULD SEE
LIGHT RAIN BECOME MORE WIDESPREAD...BUT WITHOUT MUCH OF STRONG
MOISTURE TAP AHEAD OF THE TROUGH WITH THE NORTHERN STREAM SHORTWAVE
TROUGH...RAINFALL AMOUNTS SHOULD BE LIGHT. COOLER AIR WITH H85 TEMPS
DOWN BLO -2C SLIDES IN AFTER MIDNIGHT WED NIGHT OVER THE WEST AND
THAT SHOULD TURN ANY LINGERING RAIN TO SNOW. GFS SOUNDINGS AND H85-
H7 RH FIELDS FM THE ECMWF INDICATE MID-LEVEL DRYING MAY LEAD TO
CHANCES OF FREEZING DRIZZLE OR DRIZZLE INSTEAD OF SNOW LATE WED
NIGHT INTO THANKSGIVING MORNING WITH MOIST LAYER AT TEMPS BLO 0C BUT
MUCH WARMER THAN -10C. UPSLOPE FLOW OFF LK SUPERIOR WOULD ALSO AID
IN LOW-LEVEL LIFT AND MAYBE LEAD TO GREATER CHANCES OF DRIZZLE FOR
WEST AND NCNTRL UPR MICHIGAN. ADDED MENTION OF DZ/FZDZ IN THE GRIDS
FOR THESE AREAS.
ATTN LATER ON THANKSGIVING TURNS TO WAVE OF LOW PRESSURE THAT RIDES
NORTHEAST ALONG THE TROUGH OVER THE UPR GREAT LAKES. 00Z ECMWF
TRENDED FARTHER WEST WITH THE WAVE WHILE THE GFS TRENDED FARTHER
EAST. IF THE ECMWF IS CORRECT SWATH OF MODERATE PRECIP WOULD LIFT
BACK OVER AT LEAST THE SOUTH AND EAST CWA THANKSGIVING AFTN INTO
THU NIGHT. SINCE THE INITIAL TROUGH/COLD FRONT IS THROUGH MOST CWA
PTYPE WOULD MOSTLY BE SNOW...EXCEPT OVER FAR SCNTRL WHERE WARM AIR
LINGERS AS EVEN ECMWF SHOWS H85 TEMPS AT LEAST +1C WHEN HEAVIER QPF
IS FORECAST TO MOVE THROUGH. SFC TEMPS STILL MID 30S AS WELL SO NO
RISK OF ANY FREEZING PRECIP EITHER. JUST INLAND OVER SOUTH CENTRAL
AND OVER MOST OF THE EASTERN CWA /N WINDS LEADING TO OFFSHORE WINDS
AT ESC AND ISQ/ COULD SEE SEVERAL INCHES OF WET SNOW WITH THE ECMWF
SOLN AS 12 HR QPF BTWN 18Z THU AND 06Z FRI IS AT LEAST 0.5 IF NOT UP
TO 0.75 INCH. MEANWHILE...LATEST GFS BARELY IS OVER 0.25 INCHES FOR
THAT TIME FRAME. GEM IS MORE LIKE THE ECMWF WITH TOTAL QPF...BUT MUCH
WARMER AND WOULD RESULT IN MOSTLY RAIN FOR THOSE AREAS. WPC PREFERRED
CONSENSUS OF GFS/ECMWF/GEM. WILL CONTINUE TO MENTION THE RAIN TO SNOW
AND SOME ACCUMULATING SNOW IN THE HWO...BUT CANNOT PLAY UP THE SNOW
TOO MUCH OR GET TOO SPECIFIC YET GIVEN THE UNCERTAINTIES THAT REMAIN.
BEHIND THIS SYSTEM...TURNS COLD ENOUGH FOR LAKE EFFECT SNOW SHOWERS
OFF LK SUPERIOR FRI INTO FRI NIGHT. ON FRI...AREAS FAVORED BY N
WINDS MAY SEE SOME SNOW FOR A CHANGE...THEN WOULD BE MAINLY NW FLOW
AREAS FRI NIGHT. DRY LOW-LEVEL AIRMASS WITH STRONG HIGH BUILDING IN
SHOULD LIMIT EXTENT OF LES. BASED ON CURRENT MODEL SOLUTIONS IT IS
DOUBTFUL AMOUNTS WOULD REACH ADVY LEVELS FRI-FRI NIGHT. SLIGHT
WARMING TREND WITH GENERALLY DRY WEATHER IS EXPECTED FOR NEXT
WEEKEND.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z TUESDAY MORNING)
ISSUED AT 644 AM EST MON NOV 23 2015
A DISTURBANCE MOVING ACROSS THE REGION WILL BRING SOME PATCHY -SN
THIS MORNING. WITH THE PASSAGE OF A SFC TROF...LAKE EFFECT -SHSN
WILL DEVELOP FOR AREAS FAVORED BY NW WINDS THIS AFTN AND TONIGHT.
FOR KCMX/KIWD...THIS MEANS MVFR CONDITIONS SHOULD PREVAIL THRU THE
FCST PERIOD. AT KSAW...VFR CONDITIONS SHOULD PREVAIL THIS MORNING
UNDER LINGERING DRIER AIR AT THE LOW LEVELS...THOUGH THERE MAY A
PERIOD OF MVFR VIS IN -SN. VFR SHOULD CONTINUE INTO THE MID AFTN
WITH A DOWNSLOPE WESTERLY WIND. MVFR CONDITIONS SHOULD THEN DEVELOP
AT KSAW LATE AFTN AND CONTINUE THRU TONIGHT.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 450 AM EST MON NOV 23 2015
NO GALES ARE EXPECTED ON LAKE SUPERIOR THRU THE END OF THE WEEK.
PREVIOUSLY...THERE WERE INDICATIONS OF A GALE EVENT THU NIGHT/FRI
AFTER A COLD FRONT PASSES. HOWEVER...IT NOW APPEARS THAT THE FRONT
WILL BE WEAKER SO THAT WINDS WILL REMAIN BLO GALE FORCE. LIGHTEST
WINDS THIS WEEK WILL OCCUR TUE AS A HIGH PRES RIDGE QUICKLY SHIFTS
ACROSS THE UPPER GREAT LAKES. STRONGEST WINDS THIS WEEK WILL OCCUR
LATE TUE NIGHT/WED OVER THE E HALF OF LAKE SUPERIOR IN THE SOUTHERLY
FLOW AHEAD OF THE AFOREMENTIONED COLD FRONT AND THEN LATE THU/FRI
AFTER THE FRONT PASSES.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...ROLFSON
LONG TERM...JLA
AVIATION...ROLFSON
MARINE...ROLFSON
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
450 AM EST MON NOV 23 2015
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 450 AM EST MON NOV 23 2015
WATER VAPOR IMAGERY AND RAP ANALYSIS SHOW A TROF EXTENDING S THRU
THE GREAT LAKES REGION. SHEARED OUT SHORTWAVE/LEFT EXIT OF 120+KT
UPPER JET EXTENDING FROM SASKATCHEWAN INTO THE UPPER MISSISSIPPI
VALLEY HAS GENERATED SOME AREAS OF -SN INTO WRN UPPER MI OVERNIGHT.
MODELS OVER THE LAST DAY OF RUNS CORRECTLY TRENDED LIGHTER WITH THIS
PCPN AS SNOW THAT HAS OCCURRED HAS BEEN VERY LIGHT WITH NOT MUCH
MORE THAN A DUSTING OF ACCUMULATION WHERE SNOW HAS FALLEN PER
WEBCAMS. TO THE E...JUST AS SOME HIGH RES MODELS WERE INDICATING 24
HRS AGO...THE REGIONAL CANADIAN IN PARTICULAR...A BURST OF HVY SNOW
MOVED N OFF NRN LAKE MI INTO PARTS OF THE ERN U.P. OVER THE LAST
SEVERAL HRS. IT APPEARS THE EXTREME SE CORNER OF LUCE COUNTY
PROBABLY SAW A VERY BRIEF PERIOD OF MDT TO HVY SNOW AROUND 06Z. THAT
AREA OF MDT/HVY SNOW HAS SHIFTED E INTO THE STRAITS VCNTY SINCE
THEN.
THERE IS STILL SOME CONCERN FOR LAKE ENHANCED SNOW OFF NRN LAKE MI
TO SHIFT/REFORM BACK TO THE W TODAY. ON THE HIGH EXTREME IS THE
REGIONAL CANADIAN WHICH GENERATES 0.3 INCHES OF QPF IN THE FAR SE
CORNER OF LUCE COUNTY BTWN 15Z AND 00Z. SINCE THE MAJORITY OF AVBL
HIGH RES GUIDANCE...INCLUDING THE HIGH RES CANADIAN...KEEPS THE BULK
OF REDEVELOPING LAKE ENHANCED SNOW JUST E OF LUCE COUNTY...WILL KEEP
SNOW AMOUNTS UNDER ADVY CRITERIA WITH PERHAPS 1.5-2 INCHES TO THE SE
OF KERY. ELSEWHERE....PATCHY -SN MOVING ACROSS WRN UPPER MI ATTM
SHOULD DISSIPATE OVER THE NEXT SEVERAL HRS AS IT SHIFTS E AND HAS TO
OVERCOME INITIAL DRY LOWER LEVEL AIR. THEN...A SFC LOW PRES TROF
WILL SWING INTO WRN UPPER MI LATE MORNING/AFTN...BRINGING A WIND
SHIFT TO THE W TO NW. EXPECT -SHSN TO ACCOMPANY THE TROF AS OVERLAKE
INSTABILITY WITH 850MB TEMPS AROUND -7C WILL BE MORE THAN SUFFICIENT
TO GENERATE -SHSN ALONG THE TROF/CONVERGENCE ZONE AS IT CROSSES WRN
LAKE SUPERIOR. THIS WILL THEN TRANSITION TO SCT LAKE EFFECT
-SHSN INTO TONIGHT FOR AREAS FAVORED BY NW WINDS AS 850MB TEMPS DROP
A DEGREE OR TWO C. INITIALLY...INVERSION IS UP AROUND 7KFT THIS
EVENING...BUT FALLS TO AROUND 4KFT W OVERNIGHT AND TO AROUND 5KFT E
LATE. DESPITE THE DECENTLY HIGH INVERSION HEIGHTS...SNOW
ACCUMULATIONS WILL BE LIMITED DUE TO THE DGZ BEING ABOVE THE
CONVECTIVE LAYER. AT THIS POINT...EXPECT ACCUMULATIONS MOSTLY UNDER
1 INCH...BUT IF ANY RELATIVELY STATIONARY BANDS SET UP...THERE
CERTAINLY COULD BE ISOLATED 2-3 INCH AMOUNTS.
.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 422 AM EST MON NOV 23 2015
...RAIN CHANGING TO SNOW WED NIGHT INTO THANKSGIVING DAY WITH
ACCUMULATING SNOW POSSIBLE INTO THU NIGHT...
IN LARGER SCALE...DEEP TROUGH OVER EASTERN CONUS SLIDES TO EASTERN
CANADA ON TUE WHILE SPLIT FLOW TROUGHING DEVELOPS WESTERN CANADA TO
WESTERN CONUS. 1000-850MB TROUGH FORMING ON TUE OVER ROCKIES AND
ADJACENT PLAINS AND LOW-LEVEL HIGH PRESSURE SETTLING TO SOUTHEAST
CONUS WILL ALLOW S/SE WINDS AT SFC TO BRING INCREASING MOISTURE OFF
THE GULF OF MEXICO TOWARD THE MIDDLE MISSISSIPPI RIVER VALLEY. WILL
STAY DRY OVER UPR LAKES ON TUE BUT LATE TUE NIGHT INTO WED MORNING
SOUNDINGS SHOW INCREASING MOISTURE BLO H9 INTO UPPER GREAT LAKES.
IF THERE IS ANY PRECIP AROUND ON WED MORNING...IT LIKELY WOULD TAKE
FORM OF DZ/FZDZ DEPENDING ON SFC TEMPS. BEST CHANCE FOR LIGHT ICING
WOULD BE OVER INTERIOR CNTRL CWA FM IRON/DICKINSON INTO BARAGA AND
WESTERN MARQUETTE COUNTY. MODELS SOMETIMES ARE TOO OVERDONE ON THIS
TYPE OF LOW-LEVEL MOISTENING BUT IN THIS CASE THERE IS DECENT SNOW
PACK JUST TO THE SOUTH SO THAT MAY HELP THE EXPANSION OF LOW-LEVEL
MOISTURE.
LATER ON WEDNESDAY DEEPER MOISTURE AND LARGER SCALE FORCING INCREASE
STEADILY AHEAD OF SHORTWAVE TROUGH SLIDING OVER MANTIOBA AND
NORTHERN ONTARIO. LOW-LEVEL THETA-E ADVECTION INCREASES BRIEFLY
BEFORE BEING SHUNTED TO THE SOUTH AND EAST ON WED NIGHT. SHOULD SEE
LIGHT RAIN BECOME MORE WIDESPREAD...BUT WITHOUT MUCH OF STRONG
MOISTURE TAP AHEAD OF THE TROUGH WITH THE NORTHERN STREAM SHORTWAVE
TROUGH...RAINFALL AMOUNTS SHOULD BE LIGHT. COOLER AIR WITH H85 TEMPS
DOWN BLO -2C SLIDES IN AFTER MIDNIGHT WED NIGHT OVER THE WEST AND
THAT SHOULD TURN ANY LINGERING RAIN TO SNOW. GFS SOUNDINGS AND H85-
H7 RH FIELDS FM THE ECMWF INDICATE MID-LEVEL DRYING MAY LEAD TO
CHANCES OF FREEZING DRIZZLE OR DRIZZLE INSTEAD OF SNOW LATE WED
NIGHT INTO THANKSGIVING MORNING WITH MOIST LAYER AT TEMPS BLO 0C BUT
MUCH WARMER THAN -10C. UPSLOPE FLOW OFF LK SUPERIOR WOULD ALSO AID
IN LOW-LEVEL LIFT AND MAYBE LEAD TO GREATER CHANCES OF DRIZZLE FOR
WEST AND NCNTRL UPR MICHIGAN. ADDED MENTION OF DZ/FZDZ IN THE GRIDS
FOR THESE AREAS.
ATTN LATER ON THANKSGIVING TURNS TO WAVE OF LOW PRESSURE THAT RIDES
NORTHEAST ALONG THE TROUGH OVER THE UPR GREAT LAKES. 00Z ECMWF
TRENDED FARTHER WEST WITH THE WAVE WHILE THE GFS TRENDED FARTHER
EAST. IF THE ECMWF IS CORRECT SWATH OF MODERATE PRECIP WOULD LIFT
BACK OVER AT LEAST THE SOUTH AND EAST CWA THANKSGIVING AFTN INTO
THU NIGHT. SINCE THE INITIAL TROUGH/COLD FRONT IS THROUGH MOST CWA
PTYPE WOULD MOSTLY BE SNOW...EXCEPT OVER FAR SCNTRL WHERE WARM AIR
LINGERS AS EVEN ECMWF SHOWS H85 TEMPS AT LEAST +1C WHEN HEAVIER QPF
IS FORECAST TO MOVE THROUGH. SFC TEMPS STILL MID 30S AS WELL SO NO
RISK OF ANY FREEZING PRECIP EITHER. JUST INLAND OVER SOUTH CENTRAL
AND OVER MOST OF THE EASTERN CWA /N WINDS LEADING TO OFFSHORE WINDS
AT ESC AND ISQ/ COULD SEE SEVERAL INCHES OF WET SNOW WITH THE ECMWF
SOLN AS 12 HR QPF BTWN 18Z THU AND 06Z FRI IS AT LEAST 0.5 IF NOT UP
TO 0.75 INCH. MEANWHILE...LATEST GFS BARELY IS OVER 0.25 INCHES FOR
THAT TIME FRAME. GEM IS MORE LIKE THE ECMWF WITH TOTAL QPF...BUT MUCH
WARMER AND WOULD RESULT IN MOSTLY RAIN FOR THOSE AREAS. WPC PREFERRED
CONSENSUS OF GFS/ECMWF/GEM. WILL CONTINUE TO MENTION THE RAIN TO SNOW
AND SOME ACCUMULATING SNOW IN THE HWO...BUT CANNOT PLAY UP THE SNOW
TOO MUCH OR GET TOO SPECIFIC YET GIVEN THE UNCERTAINTIES THAT REMAIN.
BEHIND THIS SYSTEM...TURNS COLD ENOUGH FOR LAKE EFFECT SNOW SHOWERS
OFF LK SUPERIOR FRI INTO FRI NIGHT. ON FRI...AREAS FAVORED BY N
WINDS MAY SEE SOME SNOW FOR A CHANGE...THEN WOULD BE MAINLY NW FLOW
AREAS FRI NIGHT. DRY LOW-LEVEL AIRMASS WITH STRONG HIGH BUILDING IN
SHOULD LIMIT EXTENT OF LES. BASED ON CURRENT MODEL SOLUTIONS IT IS
DOUBTFUL AMOUNTS WOULD REACH ADVY LEVELS FRI-FRI NIGHT. SLIGHT
WARMING TREND WITH GENERALLY DRY WEATHER IS EXPECTED FOR NEXT
WEEKEND.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT)
ISSUED AT 1225 AM EST MON NOV 23 2015
A DISTURBANCE MOVING THROUGH THE REGION WILL BRING LIGHT SNOW INTO
THE WEST HALF OF UPPER MI. THIS SHOULD GRADUALLY DROP CONDITIONS
INTO THE MVFR RANGE LATE IN THE NIGHT. EVEN THOUGH ANY SNOW TODAY
WILL BE LIGHT...MVFR CONDITIONS WILL PERSIST AS LOW LEVEL MOISTURE
LINGERS ACROSS THE REGION. HOWEVER...WNW WINDS WITH MORE OF A
DOWNSLOPE COMPONENT WILL FAVOR VFR CIGS AT KSAW.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 450 AM EST MON NOV 23 2015
NO GALES ARE EXPECTED ON LAKE SUPERIOR THRU THE END OF THE WEEK.
PREVIOUSLY...THERE WERE INDICATIONS OF A GALE EVENT THU NIGHT/FRI
AFTER A COLD FRONT PASSES. HOWEVER...IT NOW APPEARS THAT THE FRONT
WILL BE WEAKER SO THAT WINDS WILL REMAIN BLO GALE FORCE. LIGHTEST
WINDS THIS WEEK WILL OCCUR TUE AS A HIGH PRES RIDGE QUICKLY SHIFTS
ACROSS THE UPPER GREAT LAKES. STRONGEST WINDS THIS WEEK WILL OCCUR
LATE TUE NIGHT/WED OVER THE E HALF OF LAKE SUPERIOR IN THE SOUTHERLY
FLOW AHEAD OF THE AFOREMENTIONED COLD FRONT AND THEN LATE THU/FRI
AFTER THE FRONT PASSES.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...ROLFSON
LONG TERM...JLA
AVIATION...JLB
MARINE...ROLFSON
AREA FORECAST DISCUSSION...UPDATED AVIATION
NWS ST LOUIS MO
549 PM CST TUE NOV 24 2015
.SHORT TERM: (Tonight through Thanksgiving Night)
Issued at 331 PM CST Tue Nov 24 2015
Surface ridge continues to move eastward bringing increased moisture
into the area with a southerly flow ahead of cold front. ECMWF/NAM
have slowed the movement of the front which lowers the precip
chances on Wednesday. Rain chances increase from Wednesday night
into Thanksgiving evening, especially in the northwest corner of the
region as the front progresses toward the area. Temps for the
forecast period increase as southerly winds continue.
Gosselin/Walsh
.LONG TERM: (Friday through Next Tuesday)
Issued at 331 PM CST Tue Nov 24 2015
Behind the cold front...temperatures will cool back to near normal
during the day and slightly above normal at night. Unsettled
conditions with a mostly cloudy to overcast sky and at least small
chances of light rain each forecast period. Best chance of
widespread rain looks to be early on Friday but likely PoPs continue
for portions of southeastern Missouri and southwest Illinois through
Saturday night as a sfc low travels northeastward roughly along the
Ohio River.
Some chance of rain however will remain at least for portions of the
area all the way into Tuesday as broad southwest mid/upper level
flow continue over the mid-Mississippi Valley. Closed upper-level
low looks to finally move into the Great Lakes by Tuesday with a
cold front moving through the area Monday night/Tuesday. Behind this
front...drier weather should move into the area.
As for potential of frozen or freezing precipiation for this weekend
and early next week....it appears sfc temps will remain above
freezing areawide even at night with just plain rain far and away
the most likely precipitation type. If strength of cold airmass is
underdone however...freezing rain would occur if sfc temps dipped
below freezing across portions of northeast Missouri and west-
central Illinois.
Gosselin/Walsh
&&
.AVIATION: (For the 00z TAFs through 00z Wednesday Evening)
Issued at 536 PM CST Tue Nov 24 2015
No major changes to going forecast trends, with increasing
southerly flow and increasing low level moisture the primary
forecast concerns. Wind profiles in the latest forecast soundings
continue to support the development of a low level jet overnight,
with speeds ramping up into the 35-40kt range just below 1kft.
Therefore will continue LLWS forecast, with some minor tweaks to
timing in a few areas.
Meanwhile, north-south stratus deck developed in the low level
moisture return from southeast KS into central TX during the
afternoon. Plan view RH progs from both RUC and NAM suggest that
the leading edge of these clouds...with VFR bases...will
overspread TAF sites in the LSX CWA during the predawn and early
morning hours, with cigs in the KCOU area likely dropping below
3kft after 12z where low level moisture will be a bit deeper.
Specifics for KSTL: VFR conditions expected throughout the period,
with the development of the low level jet producing low level wind
profiles favorable for low level wind shear concerns from late
tonight into Wednesday morning. High level cirrus clouds
overnight will give way to lower end VFR ceilings by mid-morning
Wednesday...with bases 4-6kft. Primary rain threat with
approaching system will likely hold off until Thursday/Thursday
night.
Truett
&&
.PRELIMINARY POINT TEMPS/POPS:
Saint Louis 41 58 52 63 / 0 5 20 40
Quincy 39 54 50 61 / 0 20 40 70
Columbia 42 58 51 63 / 5 10 30 60
Jefferson City 42 59 53 64 / 5 10 30 60
Salem 39 60 49 62 / 0 5 10 30
Farmington 39 57 50 61 / 0 5 20 40
&&
.LSX WATCHES/WARNINGS/ADVISORIES:
MO...NONE.
IL...NONE.
&&
$$
WFO LSX
AREA FORECAST DISCUSSION
NWS GLASGOW MT
904 AM MST MON NOV 23 2015
.SHORT TERM...FOR NORTHEAST MONTANA...TODAY THROUGH WEDNESDAY...
MORNING UPDATE...
CHANGES FOR THIS MORNING WERE FOCUSED ON THE LIGHT ECHOS ACROSS
THE AREA. A LARGE HOLE EXISTS AROUND THE RADAR ON COMPOSITE MODE
AND THEREFORE MOST OF THESE ECHOS ARE NOT REACHING THE GROUND.
HOWEVER... WHERE ECHOS EXCEED ROUGHLY 20 TO 25 DBZ SOME LIGHT
FLURRIES WILL BE POSSIBLE. SO, HAVE UPDATED WX GRIDS TO INCLUDE
FLURRIES THROUGH THE EARLY AFTERNOON. RAP WAS USED TO BLEND INTO
THE POPS TO ACCOUNT FOR FLURRIES AS IT SEEMS TO BE ABOUT THE MOST
ACCOUNTABLE MODEL AT THE MOMENT. SKY CONDITIONS WERE ALSO TWEAKED
SLIGHTLY TO INCLUDE THESE BANDS OF ECHOS PASSING THROUGH. GAH
PREVIOUS SHORT TERM DISCUSSION...
THE UPPER LEVEL RIDGE FLATTENS OUT TODAY RESULTING IN ZONAL FLOW
ALOFT. OFF TO THE WEST A FAST MOVING UPPER TROUGH WILL BE DROPPING
SOUTH FROM THE GULF OF ALASKA AND NORTHERN BC. THIS WILL PUSH
COLDER AIR SOUTH INTO NORTHEAST MONTANA TODAY. BY 00Z THIS EVENING
THE BASE OF THE TROUGH WILL BE TO THE WEST OF WASHINGTON AND BC
EJECTING MOISTURE INTO THE SOUTHERN BC AND ALBERTA. THE FLOW
DIRECTION WILL AVOID OUR AREA UNTIL TUESDAY. SO EXPECT COOLER BUT
CONTINUED DRY CONDITIONS THROUGH TONIGHT. MODELS SUGGEST TUESDAY
MORNING AND MUCH OF TUESDAY AFTERNOON STAYING DRY WHILE CLOUDS
INCREASE FROM THE NORTHWEST AS THE COLD FRONT DESCENDS INTO
MONTANA. THE TROUGH BEGINS TO SPLIT APART WITH THE SOUTHERN
PORTION HEADING INTO NORTHERN CALIFORNIA...WHERE IT KEEPS PICKING
UP PACIFIC MOISTURE.
TUESDAY NIGHT AND WEDNESDAY...THE FAST-MOVING STORM IMPACTS THE
LOCAL REGION WITH CAA FROM WIND THAT SHIFTS TO THE NORTH AND
PRECIPITATION THAT STARTS AS RAIN...BUT TURNS INTO ACCUMULATING
SNOW. AT 00Z WEDNESDAY...LIGHT PRECIPITATION IS JUST MOVING INTO
OUR WESTERN COUNTIES. THEN IT SPREADS TOTALLY ACROSS THE AREA
OVERNIGHT. AS THE MODELS EVOLVE CLOSER TO THE EVENT...GFS QPF
CONTINUES TO TREND LOWER FOR THE CWA...AS EVIDENCED BY THE WPC
WINTER DESK ANALYSIS. THE HEAVIEST GFS QPF WILL BE THROUGH
CENTRAL MONTANA...THEN SOUTHEAST MONTANA. LOCALLY...QPF SHOULD BE
HEAVIEST IN OUR SOUTHWEST AREAS. THE NAM IS MUCH MORE WET WITH QPF
AMOUNTS ACROSS SOUTHERN PORTIONS OF THE CWA. DUE TO MODEL
DIFFERENCES...WILL CONTINUE TO GO WITH A BLEND. MOST
PRECIPITATION WILL END NORTH OF THE MISSOURI RIVER BEFORE NOON
WEDNESDAY...AND BEFORE MIDNIGHT SOUTH OF THE MISSOURI. WHAT WILL
BE LEFT ARE ROADS THAT MAY BE AFFECTED BY SNOW AND ICE WHICH COULD
CAUSE HOLIDAY TRAVEL PROBLEMS. SCT
.LONG TERM...WEDNESDAY NIGHT THROUGH MONDAY...
HIGH PRESSURE WILL CONTINUE TO BUILD INTO THE AREAS WEDNESDAY
NIGHT. THIS WILL PUSH THE SNOW COMPLETELY SOUTH OF THE FORECAST
AREA DURING THE NIGHT POSSIBLY SOONER. WILL MAINTAIN A CHANCE OF
SNOW IN THE SOUTH FOR NOW. TEMPERATURES WILL BE SOMEWHAT COLDER
THAN NORMAL BUT NOT BITTER COLD AS LOWS IN THE SINGLE DIGITS ARE
EXPECTED IN MOST AREAS.
THE SURFACE HIGH WILL CONTINUE TO BRING DRY WEATHER ON THURSDAY. A
NORTH TO NORTHWEST FLOW ALOFT IN THE NORTHERN BRANCH UPPER TROUGH
WILL KEEP TEMPERATURE ABOUT 10 DEGREES BELOW NORMAL.
UPPER LEVEL HIGH BUILDS INTO WESTERN CANADA FRIDAY AND SATURDAY
WHILE CLOSED UPPER LOW REMAINS OVER NEVADA AND CALIFORNIA. THIS
WILL RESULT IN AN UNUSUAL NORTHEAST TO EAST FLOW ALOFT. SINCE THE
FLOW ALOFT WILL BE ANTI-CYCLONIC...LOOK FOR DRY WEATHER TO
CONTINUE WITH MODERATING TEMPERATURES.
MODEL DIFFERENCES START APPEARING OVER THE WEEKEND AS THE GFS
WANTS TO BRING THE UPPER LOW TO THE SOUTH TOWARDS MONTANA ON
SUNDAY WHILE ECMWF WANTS TO RIDGE THE UPPER HIGH INTO THE AREA AND
KEEP THE LOW TO THE SOUTH. WILL LEAN TOWARDS THE DRIER ECMWF FOR
NOW AND CONTINUE THE WARMING TREND FOR NOW. THE ECMWF MAINTAINS
THAT RIDGE ON MONDAY WHILE THE GFS MOVES THE LOW TO THE EAST. FORRESTER
&&
.AVIATION...
VFR WITH A MIX OF MID AND HIGH CLOUDS TODAY AND TONIGHT. A FEW
FLURRIES MAY ALSO OCCUR AS A WARM FRONT LIFTS ACROSS THE REGION
TODAY.
VARIABLE WINDS LESS THAN 10 KNOTS EARLY WILL BECOME EAST TO
SOUTHEAST 10 TO 15 KNOTS BY AFTERNOON AND CONTINUE TONIGHT.
&&
.GLASGOW WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
WEATHER.GOV/GLASGOW
AREA FORECAST DISCUSSION
NWS NORTH PLATTE NE
240 PM CST MON NOV 23 2015
.SYNOPSIS...
ISSUED AT 239 PM CST MON NOV 23 2015
BROAD NWRLY FLOW ALOFT FORMED BY A SLOWLY EXITING LONG WAVE TROUGH
ACROSS THE EASTERN STATES AND BROAD...WEAK RIDGING IN THE WEST. OFF
THE BC COAST...A DEVELOPING LONG WAVE TROUGH WHICH WILL BE SLIDING
EWD TO THE WEST COAST. LEAD SHORT WAVE/PV ANOMALY MOVING ONTO THE
CENTRAL CA COAST CURRENTLY PRODUCING BAROCLINIC LEAF OVER NV. CLOSER
TO HOME...SATELLITE IMAGERY SHOWING SNOW FIELD ACROSS PORTIONS OF NC
NEB CONTINUING TO ERRODE SLOWLY AS TEMPS WARM QUICKLY UNDER MOSTLY
FULL SUNSHINE AND DESPITE LIGHT WIND.
&&
.SHORT TERM...(THIS EVENING THROUGH TUESDAY)
ISSUED AT 239 PM CST MON NOV 23 2015
BIGGEST CONCERN OVERNIGHT IS THE POTENTIAL FOR FOG/LOW CLOUDS IN
PORTIONS OF THE NC FCST AREA. NAM/SREF HAVE BEEN CONSISTENT AT
SUGGESTING THIS AND NAM BUFR SOUNDINGS SHOW A LAYER OF TRAPPED COLD
AIR FROM THE SFC TO ABOUT 600 FT. NAM HAS ISSUES WITH LOWER
LAYER IN AND NEAR SNOW COVER...BUT COULD STILL BE SUGGESTING A
REALISTIC POTENTIAL. SREF VSBY PROBS SHOW GOOD POTENTIAL FOR
REDUCED VSBY IN THE 06-12Z TUES TIME FRAME. MEANWHILE THE RAP BUFR
SOUNDINGS ARE NOT SHOWING THIS AND GFS LAMP GUIDANCE HAS BACKED
OFF. FROM AN OBSERVATIONAL PERSPECTIVE LIGHT SOUTHEASTERLY WINDS
OVERNIGHT IN CONCERT WITH ANY RESIDUAL MOISTURE FROM MELTING SNOW
WOULD SUGGEST NAM COULD BE ON TO SOMETHING. HAVE ADDED PATCHY FOG
TO THE FCST THOUGH WILL HAVE TO MONITOR FOR MORE STRONGER WORDING
IF DEVELOPMENT DOES OCCUR.
PREVIOUSLY MENTIONED LEAD SHORT WAVE WILL PIVOT NEWD INTO THE HIGH
PLAINS DURING THE DAY TUES. ASSOCIATED HEIGHT FALLS WILL SERVE TO
KICK THE PREVIOUSLY DEVELOPED SFC TROUGH EWD DURING THE DAY
WHICH...BECAUSE OF DRY LOWER LEVELS...SHOULD ONLY RESULT IN A WIND
SHIFT FROM SERLY TO SRLY OR SWRLY BEHIND SFC TROUGH. WEAK LARGE
SCALE LIFT WILL TEMPER HIGHS A BIT TMRW...BUT BY LATE IN THE DAY
SUBSIDENCE BECOMES RE-ESTABLISHED AND WOULD EXPECT TEMPS TO RETURN
TO ABOVE NORMAL VALUES AGAIN. HAVE TRENDED FCST TWD THE HIGH END OF
THE ENVELOPE OF POSSIBILITIES AS A RESULT AND ALSO BECAUSE TEMPS
HAVE WARMED ABOVE EXPECTTED LEVELS THE LAST TWO DAYS. TEMPS WILL
CONTINUE TO BE HELD DOWN WHERE SNOW COVER STILL REMAINS IN NC NEB
AND ALSO IF CLOUDS DO FORM THEY WILL INHIBIT INSOLATION DURING THE
MORNING HOURS. OTHERWISE LITTLE IN THE WAY OF FCST CONCERNS FOR
TUES.
.LONG TERM...(TUESDAY NIGHT THROUGH MONDAY)
ISSUED AT 239 PM CST MON NOV 23 2015
SOUTHERLY LOW LEVEL FLOW WILL BEGIN TO DRAW MOISTURE NORTHWARD INTO
THE CENTRAL PLAINS TUESDAY NIGHT. MODELS INDICATE THAT STRATUS
WILL DEVELOP AND SPREAD NORTHWARD TUESDAY NIGHT. RIGHT NOW IT
APPEARS THAT MOST OF THAT WILL BE DIRECTED TOWARD CENTRAL AND EASTERN
NEBRASKA...BUT MAY CLIP THE VERY FAR EASTERN PORTIONS OF THE AREA.
HAVE INTRODUCED PATCHY FOG INTO THE SRN ZONES LATE TUESDAY NIGHT
INTO EARLY WEDNESDAY MORNING.
AN ARCTIC COLD FRONT WILL SWEEP SOUTH THROUGH THE AREA WEDNESDAY.
AT THE SAME TIME A LEAD WAVE WILL BEGIN TO EJECT EASTWARD FROM THE
WESTERN CONUS UPPER LOW. EXPECT FALLING TEMPERATURES WEDNESDAY
AFTERNOON AS THE COLD FRONT PASSES AS WELL AS AN INCREASE IN MID
AND UPPER LEVEL CLOUDS. MAY NOT SEE THE HIGHER CLOUDS
HOWEVER...AS LOW STRATUS CLOUDS WILL QUICKLY INCREASE/DEVELOP
SOUTHWARD BEHIND THE FRONT.
ARCTIC AIR WILL BE FILTERING SOUTH THROUGH THE AREA WEDNESDAY NIGHT
BEHIND THE COLD FRONT. A PERIOD OF LIGHT DRIZZLE AND FREEZING
DRIZZLE DURING THE EVENING TO FREEZING DRIZZLE/SNOW AFTER
MIDNIGHT. NAM BUFKIT SOUNDING INDICATE A FREEZING DRIZZLE
SOUNDING...WHILE THE GFS KEEPS THE LOWEST LEVELS DRIER. WITH
CONSIDERABLE DRY AIR ALOFT NOT SURE WE WILL SEE MUCH SNOW. MAY BE
MORE FREEZING DRIZZLE.
THE LEAD WAVE WILL CROSS THE CENTRAL AND SOUTHERN PLAINS
THANKSGIVING. MOST OF THE PRECIPITATION WILL REMAIN EAST AND
SOUTHEAST OF THE IMMEDIATE AREA...BUT SOME VERY LIGHT SNOW IS
POSSIBLE WITH ACCUMULATIONS EXPECTED TO REMAIN A DUSTING. NOT MUCH
CHANGE TO HIGHS WITH MID TO UPPER 20S FCST. NORTH TO NORTHEAST
WINDS 10 TO 20 MPH HOWEVER WILL GIVE WIND CHILLS IN THE TEENS.
FOR THE WEEKEND...PARTICULARLY SATURDAY INTO MONDAY...OPERATIONAL
MODELS EJECT THE LARGE UPPER LEVEL TROUGH EASTWARD INTO THE
CENTRAL PLAINS. PLENTY OF QUESTIONS REGARDING TIMING. FOR NOW
WILL CARRY A SLIGHT TO LOW CHANCE POP FOR SNOW SATURDAY INTO
MONDAY. OTHERWISE CONTINUED COLD WITH BELOW NORMAL TEMPERATURES
IN THE MID 30S.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON)
ISSUED AT 1130 AM CST MON NOV 23 2015
VFR CONDITIONS THROUGH THE FIRST PART OF THE FCST BUT SOME CONCERN
FOR VSBY RESTRICTIONS AND IFR CIGS LATE TONIGHT AT KVTN.
TRANSITORY RIDGING ALOFT WILL MOVE ACROSS THE PLAINS AS LONG WAVE
TROUGH OVER THE EAST MOVES OUT. THE RESULT WILL BE A MORE ZONAL
FLOW ALOFT WHICH WILL SERVE TO DEVELOP LOW PRESSURE ALONG THE LEE
OF THE ROCKIES. SFC RESULT IS A WEAK FRONTAL BOUNDARY RETREATING
EWD AS WARM AIR DESCENDS FROM THE WEST. SOME MID/HIGH CLOUDS
RESULTING FROM THE ISENTROPIC LIFT THIS AFTERNOON PUSHING EWD.
THIS WILL SETUP A FAVORABLE PATTERN TONIGHT FOR LOW CLOUDS AND
FOG...WHICH THE NAM AND THE 23.09Z SREF PICK UP ON. SKEPTICAL OF
THE NAM DUE ITS TENDENCY TO NOT MIX THE LOW LAYERS ENOUGH DURING
THE DAY AND DEVELOP TOO MUCH COLD AIR NEAR THE SFC AT NIGHT.
BUT...SINCE THIS IS A PATTERN FAVORABLE HAVE TRENDED THE FCST FOR
KVTN IN THAT MANNER THOUGH CONFIDENCE IS ONLY MEDIUM AT THIS
POINT. NO RESTRICTIONS IN THE FCST AT THIS TIME FOR KLBF.
&&
.LBF WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...STOPPKOTTE
SHORT TERM...STOPPKOTTE
LONG TERM...ROBERG
AVIATION...STOPPKOTTE
AREA FORECAST DISCUSSION
NWS GRAND FORKS ND
706 PM CST TUE NOV 24 2015
.UPDATE...
ISSUED AT 659 PM CST TUE NOV 24 2015
VERY TRICKY FCST. MODEL SOUNDINGS AND VARIOUS SHORT RANGE MODELS
DO HAVE A SATURATION IN THE SUB 850 MB LAYER OVERNIGHT...MOSTLY
LATE TONIGHT INTO WED MORNING. SO IDEA OF LOW CLOUD DEVELOPMENT
DOES SEEM REASONABLE. JUST USING 925 MB RH NOT WORKING AS GFS
WOULD HAVE LOW CLOUDS NOW IS USING THAT. THE HRRR WOULD ARGUE
LOWER CIGS WILL DROP SOUTH WITH THE FRONT INTO NE ND OVERNIGHT AND
REACH SE ND/WCNTRL MN PAST 12Z. WITH UNCERTAINITY DID KEEP POST
06Z POPS/WX THE SAME AS PREV FCST BUT LOTS OF UNCERTAINITY. THE
MAIN 850 MB MOISTURE PLUME WILL SHIFT A BIT MORE EAST OVERNIGHT
WITH THE MVFR CLOUDS MOVING NORTH THRU ERN KANSAS MORE DESTINED
FOR SRN MN INTO WRN WI WEDNESDAY MORNING. DID RAISE LOWS A TAD AND
DID GO DRY THRU 06Z.
&&
.SHORT TERM...(THIS EVENING THROUGH WEDNESDAY NIGHT)
ISSUED AT 302 PM CST TUE NOV 24 2015
CHALLENGE FOR TONIGHT INTO WEDNESDAY NIGHT REMAINS DRIZZLE AND OR
FREEZING DRIZZLE WITH THE TIMING AND LIGHT SNOW WITH FROPA TOMORROW.
MOIST NEAR SFC LAYER TO DEVELOP TONIGHT...ALONG THE FRONTAL BOUNDARY
IS AN AREA WITH HIGH CONFIDENCE. ANOTHER POSSIBLE AREA...LOWER
CONFIDENCE...CONTINUES TO BE THE SOUTHERN VALLEY AND INTO WEST
CENTRAL MINNESOTA. AREAS WHERE IT DOES DEVELOP MAY CREATE THE
POSSIBILITY FOR SOME DRIZZLE OR FREEZING DRIZZLE WITH THE DRY LAYER
ALOFT. EARLY WEDNESDAY THE FROPA MOVES FROM NORTHWEST INTO THE
VALLEY BY 12 TO 15Z AND THRU THE SOUTHEAST DURING EARLY AFTN. THE
LIGHT DRIZZLE OR FREEZING DRIZZLE WILL TURN OVER TO LIGHT SNOW WITH
ANY DRIZZLE OR SNOW ACCUMULATIONS TO BE MINIMAL. SOME WIDELY
SCATTERED ICY SPOTS REMAIN POSSIBLE THOUGH TRAVEL IMPACTS ARE
EXPECTED NEGLIGIBLE.
.LONG TERM...(THURSDAY THROUGH TUESDAY)
ISSUED AT 302 PM CST TUE NOV 24 2015
THANKSGIVING DAY WILL BE RELATIVELY COLD WITH NORTHERLY SFC WINDS
BRINGING IN 925MB TEMPS AT 10C TO 15C BELOW ZERO. THIS WILL
PRODUCE DAYTIME HIGHS IN THE MID 20S. SFC HIGHS CONTINUE TO BUILD
INTO THE FA WITH CLEARING SKIES FOR THURSDAY AFTN IN TO THE
OVERNIGHT. SOME TEMP RECOVERY AS SFC WINDS TURN TO THE SW AND FULL
SUN IS EXPECTED FRIDAY AFTN BRINGING MAX TEMPS TO NEAR 30.
FRIDAY NIGHT THROUGH TUESDAY...THE FIRST PART OF THE PERIOD SHOULD
BE FAIRLY QUIET AS THE BLOCKED PATTERN CONTINUES AND THE CUT OFF LOW
IS STILL WOBBLING OVER THE WESTERN CONUS. THE MODELS ALL START
BRINGING THE CUT OFF OUT INTO THE PLAINS SUNDAY/MONDAY...ALTHOUGH
DIFFER IN THE DETAILS. CONTINUED TO KEEP THE LOW POPS THAT THE
BLENDED SOLUTION GIVES US FOR SUNDAY NIGHT AND EARLY NEXT WEEK GIVEN
THE LACK OF CERTAINTY WITH BLOCKING SYSTEMS. TEMPS SHOULD BE BACK
ABOVE SEASONAL AVERAGES.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z WEDNESDAY EVENING)
ISSUED AT 659 PM CST TUE NOV 24 2015
LOW CONFIDENCE TAF FCSTS FOR THE OVERNIGHT INTO WEDNESDAY MORNING
IN REGARDS TO DEVELOPMENT OF LIGHT FOG AND IFR CIGS. KEPT PREV TAF
IDEA IN TACT BUT PUSHED BACK TIMING A BIT TO MORE AFTER 08Z-10Z
PERIOD FOR IFR CIGS AT TAF SITES. FZDZ CHANCES THERE BUT HIGH
DEGREE OF UNCERTAINITY IN COVERAGE AND IF ANY FORMS. WIND SHIFT TO
THE NORTHWEST REACHING DVL 10Z OR SO AND THE RRV 12-14Z AND BJI
17Z OR SO.
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...NONE.
MN...NONE.
&&
$$
UPDATE...RIDDLE
SHORT TERM...JK
LONG TERM...JK/JR
AVIATION...RIDDLE
AREA FORECAST DISCUSSION
NWS BISMARCK ND
1259 PM CST MON NOV 23 2015
.UPDATE...
ISSUED AT 1256 PM CST MON NOV 23 2015
FOR THE EARLY AFTERNOON UPDATE BUMPED TEMPERATURES UP A FEW
DEGREES MOST AREAS. DID TEMPER HIGHS A LITTLE OVER THE FAR
SOUTHWEST WHERE PERSISTENT MID AND HIGH LEVEL CLOUDS REMAIN.
OTHERWISE NO SIGNIFICANT CHANGES TO THE GOING FORECAST.
UPDATE ISSUED AT 959 AM CST MON NOV 23 2015
HIGH PRESSURE WILL CONTINUE TO MOVE EAST ACROSS THE FORECAST AREA
TODAY. HIGH LEVEL CLOUDS WILL CONTINUE TO INCREASE FROM WEST TO
EAST. SOME MID LEVEL WARM ADVECTION CLOUDINESS SPREADING FROM
EASTERN MONTANA INTO SOUTHWEST NORTH DAKOTA TODAY COULD PRODUCE A
FEW FLURRIES...BUT NOT WORTH A MENTION AT THIS TIME. ADJUSTED
CLOUDS HIGHER WEST AND LOWER EAST THROUGH THE MORNING.
TEMPERATURES LOOK REASONABLE AND NO ADJUSTMENTS OTHER THAN
POPULATING THE LATEST OBSERVATIONS.
UPDATE ISSUED AT 635 AM CST MON NOV 23 2015
NO SIGNIFICANT CHANGES WERE MADE WITH THIS UPDATE CYCLE OTHER THAN
BLENDING RECENT OBSERVATIONS WITH SHORT TERM MODEL GUIDANCE. RADAR
ECHOES IN NORTHEASTERN MT REFLECT AN INCREASE IN MIDDLE- AND HIGH-
LEVEL CLOUDS AND NOT PRECIPITATION DUE TO A DRY LOWER ATMOSPHERE.
THAT SCENARIO IS WELL-REFLECTED BY RECENT HRRR ITERATIONS AND THUS
THE DRY FORECAST FOR TODAY APPEARS TO BE WELL IN HAND.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 337 AM CST MON NOV 23 2015
QUIET WEATHER HIGHLIGHTS THE SHORT TERM PERIOD.
CURRENTLY...THE STRONG LOW PRESSURE SYSTEM ASSOCIATED WITH
YESTERDAY`S WINDY CONDITIONS WAS CENTERED OVER THE BORDER OF
MANITOBA/ONTARIO/MINNESOTA. A WEAK HIGH PRESSURE AXIS EXTENDED FROM
SOUTHERN ALBERTA SOUTHEASTWARD INTO EASTERN MONTANA AND THE WESTERN
DAKOTAS...WITH BROAD LOW PRESSURE DEVELOPING IN THE LEE OF THE
ROCKIES.
TODAY THE STRONG LOW PRESSURE SYSTEM IS FORECAST TO MOVE EAST
TOWARDS THE GREAT LAKES AND HUDSON BAY...AND THE SURFACE HIGH
PRESSURE RIDGE AXIS MOVES EASTWARD INTO THE CENTRAL AND EASTERN
DAKOTAS AS AN UPPER LEVEL RIDGE BUILDS/EXPANDS FROM THE ROCKIES INTO
THE WESTERN PLAINS. MAINLY PARTLY CLOUDY SKIES TODAY WITH
MIDDLE/HIGH CLOUDS MOVING EAST INTO NORTH DAKOTA. WARMER AIR IN
SOUTHWESTERN NORTH DAKOTA WITH HIGHS IN THE LOWER 40S...WITH COOLER
AIR TO THE NORTHEAST WITH HIGHS IN THE MID TO UPPER 30S.
TONIGHT THE BROAD UPPER LEVEL RIDGE MIGRATES EASTWARD AND THE FLOW
OVER THE ROCKIES BECOMES SOUTHWESTERLY ALOFT. IN RESPONSE...BROAD
SURFACE LOW PRESSURE DEVELOPS OVER THE ROCKIES AND FRONT RANGE...AND
A LONG BROAD FETCH OF SOUTHERLY SURFACE WINDS DEVELOPS FROM THE
SOUTHERN PLAINS NORTHWARD INTO THE NORTHERN PLAINS. A LOW LEVEL JET
DEVELOPS...AND THIS WILL ALLOW LOW LEVEL MOISTURE TO STREAM
NORTHWARD INTO SOUTH CENTRAL CANADA. LOOK FOR INCREASING LOW CLOUDS
WITH SOUTHEASTERLY SURFACE WINDS...AND INCREASING MID LEVEL CLOUDS
MOVING IN FROM THE WEST/SOUTHWEST. LOW TEMPERATURES ARE EXPECTED TO
BE IN THE 20S.
.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 337 AM CST MON NOV 23 2015
THE FOCUS IN THE LONG TERM IS ON LIGHT SNOW POTENTIAL CENTERED ON
WEDNESDAY. WE ARE BECOMING MORE CONFIDENT THAT ACCUMULATIONS WILL
BE RELATIVELY LOW WITH THIS EVENT...POTENTIALLY LIMITING IMPACTS.
THE 00 UTC MODEL SUITE WAS IN RELATIVELY GOOD AGREEMENT IN SHOWING
LIGHT SNOW DEVELOPING IN WESTERN ND BY EARLY WEDNESDAY MORNING AND
SPREADING EASTWARD DURING THE DAY. THE MULTI-MODEL CONSENSUS CALLS
FOR LIQUID-EQUIVALENT MOISTURE VALUES OF 0.05 TO 0.15 INCHES /MOST
IN FAR SOUTHWESTERN ND/...WHICH SHOULD CONTRIBUTE TO SNOW AMOUNTS
RANGING FROM LESS THAN ONE-HALF INCH TO THE NORTH AND EAST OF THE
MISSOURI RIVER...TO 1 TO 2 INCHES SOUTH AND WEST OF THE MISSOURI
RIVER. OUR OFFICIAL FORECAST PRODUCED 3 INCH SNOW TOTALS ONLY IN
EXTREME SOUTHWESTERN ND...BOWMAN AND SLOPE COUNTIES...WEDNESDAY
THROUGH WEDNESDAY NIGHT.
THE SNOW WILL BE GENERATED IN A POST-FRONTAL ENVIRONMENT...DRIVEN
MAINLY BY DYNAMICS ASSOCIATED WITH A SHORTWAVE TROUGH EMBEDDED IN
THE NORTHERN STREAM OF A SPLIT FLOW. THE 03 UTC SREF LINGERED THE
SNOW LONGER THAN THE 00 UTC DETERMINISTIC GUIDANCE...SO A BIT OF
UNCERTAINTY REMAINS...BUT IN GENERAL GUIDANCE CONTINUED TO SUGGEST
THAT THE PRIMARY VERTICAL MOTION ASSOCIATED WITH THE 500-MB LOW IN
THE GREAT BASIN WILL REMAIN DISPLACED SOUTH OF ND. IF THAT IS THE
CASE...THANKSGIVING DAY MAY END UP COLD...BUT DRY IN MOST AREAS.
ONE OTHER ISSUE WE WILL NEED TO CONSIDER IS WHETHER FOG DEVELOPS
TUESDAY NIGHT...AND WHETHER LINGERING WARM AND DRY AIR ALOFT IS
CAPABLE OF PRODUCING ANY LIGHT FREEZING RAIN OR LIGHT FREEZING
DRIZZLE TUESDAY NIGHT INTO WEDNESDAY MORNING. FORECAST SOUNDINGS
ARE NOT PARTICULARLY SUGGESTIVE OF THAT POTENTIAL THOUGH...SO WE
ARE NOT MESSAGING THAT RISK AT THIS POINT.
A REX BLOCK WILL DEVELOP ALOFT OVER THE WESTERN UNITED STATES BY
NEXT WEEKEND AS THE GREAT BASIN LOW GETS PINCHED OFF TO THE SOUTH
OF A DEVELOPING 500-MB RIDGE OVER WESTERN CANADA. THIS SCENARIO IS
EXPECTED TO GENERATE A WARMING TREND AND MAINLY DRY WEATHER ACROSS
THE AREA NEXT WEEKEND...THOUGH THE 00 UTC GFS /AND THE 00 UTC GFS
ALONE/ DOES SUGGEST SOME SNOW POTENTIAL RETURNING NEXT SUNDAY WHEN
IT BREAKS THE BLOCK DOWN AND KICKS THE REMNANT LOW ALOFT EASTWARD
FURTHER NORTH THAN THE REST OF THE 00 UTC MODEL GUIDANCE.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON)
ISSUED AT 1256 PM CST MON NOV 23 2015
A BAND OF MID TO HIGH LEVEL CLOUDS WILL MOVE ACROSS NORTH DAKOTA
MONDAY AFTERNOON AND EVENING...FROM THE SOUTHWEST TO NORTHEAST. AS
WE APPROACH THE OVERNIGHT HOURS...LOWER LEVEL MOISTURE WILL
INCREASE...BRINGING MVFR CEILINGS TO KDIK...AND POSSIBLY TO ALL
OTHER SITES. MORE UNCERTAINTY REGARDING LOWER CEILINGS EXIST ACROSS
THESE OTHER SITES...SO MODEL TRENDS WILL HAVE TO BE MONITORED
CLOSELY. FOR NOW WILL JUST KEEP SCATTERED LOWER CLOUDS IN THE
FORECAST FOR KISN/KMOT/KBIS/KJMS. VARIABLE LIGHT WINDS WILL PREVAIL
ACROSS ALL SITES THROUGH THE PERIOD.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...TWH
SHORT TERM...JV
LONG TERM...CJS
AVIATION...ZH
AREA FORECAST DISCUSSION
NWS BISMARCK ND
1005 AM CST MON NOV 23 2015
.UPDATE...
ISSUED AT 959 AM CST MON NOV 23 2015
HIGH PRESSURE WILL CONTINUE TO MOVE EAST ACROSS THE FORECAST AREA
TODAY. HIGH LEVEL CLOUDS WILL CONTINUE TO INCREASE FROM WEST TO
EAST. SOME MID LEVEL WARM ADVECTION CLOUDINESS SPREADING FROM
EASTERN MONTANA INTO SOUTHWEST NORTH DAKOTA TODAY COULD PRODUCE A
FEW FLURRIES...BUT NOT WORTH A MENTION AT THIS TIME. ADJUSTED
CLOUDS HIGHER WEST AND LOWER EAST THROUGH THE MORNING.
TEMPERATURES LOOK REASONABLE AND NO ADJUSTMENTS OTHER THAN
POPULATING THE LATEST OBSERVATIONS.
UPDATE ISSUED AT 635 AM CST MON NOV 23 2015
NO SIGNIFICANT CHANGES WERE MADE WITH THIS UPDATE CYCLE OTHER THAN
BLENDING RECENT OBSERVATIONS WITH SHORT TERM MODEL GUIDANCE. RADAR
ECHOES IN NORTHEASTERN MT REFLECT AN INCREASE IN MIDDLE- AND HIGH-
LEVEL CLOUDS AND NOT PRECIPITATION DUE TO A DRY LOWER ATMOSPHERE.
THAT SCENARIO IS WELL-REFLECTED BY RECENT HRRR ITERATIONS AND THUS
THE DRY FORECAST FOR TODAY APPEARS TO BE WELL IN HAND.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 337 AM CST MON NOV 23 2015
QUIET WEATHER HIGHLIGHTS THE SHORT TERM PERIOD.
CURRENTLY...THE STRONG LOW PRESSURE SYSTEM ASSOCIATED WITH
YESTERDAY`S WINDY CONDITIONS WAS CENTERED OVER THE BORDER OF
MANITOBA/ONTARIO/MINNESOTA. A WEAK HIGH PRESSURE AXIS EXTENDED FROM
SOUTHERN ALBERTA SOUTHEASTWARD INTO EASTERN MONTANA AND THE WESTERN
DAKOTAS...WITH BROAD LOW PRESSURE DEVELOPING IN THE LEE OF THE
ROCKIES.
TODAY THE STRONG LOW PRESSURE SYSTEM IS FORECAST TO MOVE EAST
TOWARDS THE GREAT LAKES AND HUDSON BAY...AND THE SURFACE HIGH
PRESSURE RIDGE AXIS MOVES EASTWARD INTO THE CENTRAL AND EASTERN
DAKOTAS AS AN UPPER LEVEL RIDGE BUILDS/EXPANDS FROM THE ROCKIES INTO
THE WESTERN PLAINS. MAINLY PARTLY CLOUDY SKIES TODAY WITH
MIDDLE/HIGH CLOUDS MOVING EAST INTO NORTH DAKOTA. WARMER AIR IN
SOUTHWESTERN NORTH DAKOTA WITH HIGHS IN THE LOWER 40S...WITH COOLER
AIR TO THE NORTHEAST WITH HIGHS IN THE MID TO UPPER 30S.
TONIGHT THE BROAD UPPER LEVEL RIDGE MIGRATES EASTWARD AND THE FLOW
OVER THE ROCKIES BECOMES SOUTHWESTERLY ALOFT. IN RESPONSE...BROAD
SURFACE LOW PRESSURE DEVELOPS OVER THE ROCKIES AND FRONT RANGE...AND
A LONG BROAD FETCH OF SOUTHERLY SURFACE WINDS DEVELOPS FROM THE
SOUTHERN PLAINS NORTHWARD INTO THE NORTHERN PLAINS. A LOW LEVEL JET
DEVELOPS...AND THIS WILL ALLOW LOW LEVEL MOISTURE TO STREAM
NORTHWARD INTO SOUTH CENTRAL CANADA. LOOK FOR INCREASING LOW CLOUDS
WITH SOUTHEASTERLY SURFACE WINDS...AND INCREASING MID LEVEL CLOUDS
MOVING IN FROM THE WEST/SOUTHWEST. LOW TEMPERATURES ARE EXPECTED TO
BE IN THE 20S.
.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 337 AM CST MON NOV 23 2015
THE FOCUS IN THE LONG TERM IS ON LIGHT SNOW POTENTIAL CENTERED ON
WEDNESDAY. WE ARE BECOMING MORE CONFIDENT THAT ACCUMULATIONS WILL
BE RELATIVELY LOW WITH THIS EVENT...POTENTIALLY LIMITING IMPACTS.
THE 00 UTC MODEL SUITE WAS IN RELATIVELY GOOD AGREEMENT IN SHOWING
LIGHT SNOW DEVELOPING IN WESTERN ND BY EARLY WEDNESDAY MORNING AND
SPREADING EASTWARD DURING THE DAY. THE MULTI-MODEL CONSENSUS CALLS
FOR LIQUID-EQUIVALENT MOISTURE VALUES OF 0.05 TO 0.15 INCHES /MOST
IN FAR SOUTHWESTERN ND/...WHICH SHOULD CONTRIBUTE TO SNOW AMOUNTS
RANGING FROM LESS THAN ONE-HALF INCH TO THE NORTH AND EAST OF THE
MISSOURI RIVER...TO 1 TO 2 INCHES SOUTH AND WEST OF THE MISSOURI
RIVER. OUR OFFICIAL FORECAST PRODUCED 3 INCH SNOW TOTALS ONLY IN
EXTREME SOUTHWESTERN ND...BOWMAN AND SLOPE COUNTIES...WEDNESDAY
THROUGH WEDNESDAY NIGHT.
THE SNOW WILL BE GENERATED IN A POST-FRONTAL ENVIRONMENT...DRIVEN
MAINLY BY DYNAMICS ASSOCIATED WITH A SHORTWAVE TROUGH EMBEDDED IN
THE NORTHERN STREAM OF A SPLIT FLOW. THE 03 UTC SREF LINGERED THE
SNOW LONGER THAN THE 00 UTC DETERMINISTIC GUIDANCE...SO A BIT OF
UNCERTAINTY REMAINS...BUT IN GENERAL GUIDANCE CONTINUED TO SUGGEST
THAT THE PRIMARY VERTICAL MOTION ASSOCIATED WITH THE 500-MB LOW IN
THE GREAT BASIN WILL REMAIN DISPLACED SOUTH OF ND. IF THAT IS THE
CASE...THANKSGIVING DAY MAY END UP COLD...BUT DRY IN MOST AREAS.
ONE OTHER ISSUE WE WILL NEED TO CONSIDER IS WHETHER FOG DEVELOPS
TUESDAY NIGHT...AND WHETHER LINGERING WARM AND DRY AIR ALOFT IS
CAPABLE OF PRODUCING ANY LIGHT FREEZING RAIN OR LIGHT FREEZING
DRIZZLE TUESDAY NIGHT INTO WEDNESDAY MORNING. FORECAST SOUNDINGS
ARE NOT PARTICULARLY SUGGESTIVE OF THAT POTENTIAL THOUGH...SO WE
ARE NOT MESSAGING THAT RISK AT THIS POINT.
A REX BLOCK WILL DEVELOP ALOFT OVER THE WESTERN UNITED STATES BY
NEXT WEEKEND AS THE GREAT BASIN LOW GETS PINCHED OFF TO THE SOUTH
OF A DEVELOPING 500-MB RIDGE OVER WESTERN CANADA. THIS SCENARIO IS
EXPECTED TO GENERATE A WARMING TREND AND MAINLY DRY WEATHER ACROSS
THE AREA NEXT WEEKEND...THOUGH THE 00 UTC GFS /AND THE 00 UTC GFS
ALONE/ DOES SUGGEST SOME SNOW POTENTIAL RETURNING NEXT SUNDAY WHEN
IT BREAKS THE BLOCK DOWN AND KICKS THE REMNANT LOW ALOFT EASTWARD
FURTHER NORTH THAN THE REST OF THE 00 UTC MODEL GUIDANCE.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON)
ISSUED AT 959 AM CST MON NOV 23 2015
VFR CONDITIONS EXPECTED UNTIL AROUND 02Z-06Z MONDAY EVENING...WHEN
INCREASING LOW CLOUDS WILL RESULT IN MVFR CIGS AT ALL TAF SITES.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...TWH
SHORT TERM...JV
LONG TERM...CJS
AVIATION...TWH
AREA FORECAST DISCUSSION
NWS BISMARCK ND
638 AM CST MON NOV 23 2015
.UPDATE...
ISSUED AT 635 AM CST MON NOV 23 2015
NO SIGNIFICANT CHANGES WERE MADE WITH THIS UPDATE CYCLE OTHER THAN
BLENDING RECENT OBSERVATIONS WITH SHORT TERM MODEL GUIDANCE. RADAR
ECHOES IN NORTHEASTERN MT REFLECT AN INCREASE IN MIDDLE- AND HIGH-
LEVEL CLOUDS AND NOT PRECIPITATION DUE TO A DRY LOWER ATMOSPHERE.
THAT SCENARIO IS WELL-REFLECTED BY RECENT HRRR ITERATIONS AND THUS
THE DRY FORECAST FOR TODAY APPEARS TO BE WELL IN HAND.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 337 AM CST MON NOV 23 2015
QUIET WEATHER HIGHLIGHTS THE SHORT TERM PERIOD.
CURRENTLY...THE STRONG LOW PRESSURE SYSTEM ASSOCIATED WITH
YESTERDAY`S WINDY CONDITIONS WAS CENTERED OVER THE BORDER OF
MANITOBA/ONTARIO/MINNESOTA. A WEAK HIGH PRESSURE AXIS EXTENDED FROM
SOUTHERN ALBERTA SOUTHEASTWARD INTO EASTERN MONTANA AND THE WESTERN
DAKOTAS...WITH BROAD LOW PRESSURE DEVELOPING IN THE LEE OF THE
ROCKIES.
TODAY THE STRONG LOW PRESSURE SYSTEM IS FORECAST TO MOVE EAST
TOWARDS THE GREAT LAKES AND HUDSON BAY...AND THE SURFACE HIGH
PRESSURE RIDGE AXIS MOVES EASTWARD INTO THE CENTRAL AND EASTERN
DAKOTAS AS AN UPPER LEVEL RIDGE BUILDS/EXPANDS FROM THE ROCKIES INTO
THE WESTERN PLAINS. MAINLY PARTLY CLOUDY SKIES TODAY WITH
MIDDLE/HIGH CLOUDS MOVING EAST INTO NORTH DAKOTA. WARMER AIR IN
SOUTHWESTERN NORTH DAKOTA WITH HIGHS IN THE LOWER 40S...WITH COOLER
AIR TO THE NORTHEAST WITH HIGHS IN THE MID TO UPPER 30S.
TONIGHT THE BROAD UPPER LEVEL RIDGE MIGRATES EASTWARD AND THE FLOW
OVER THE ROCKIES BECOMES SOUTHWESTERLY ALOFT. IN RESPONSE...BROAD
SURFACE LOW PRESSURE DEVELOPS OVER THE ROCKIES AND FRONT RANGE...AND
A LONG BROAD FETCH OF SOUTHERLY SURFACE WINDS DEVELOPS FROM THE
SOUTHERN PLAINS NORTHWARD INTO THE NORTHERN PLAINS. A LOW LEVEL JET
DEVELOPS...AND THIS WILL ALLOW LOW LEVEL MOISTURE TO STREAM
NORTHWARD INTO SOUTH CENTRAL CANADA. LOOK FOR INCREASING LOW CLOUDS
WITH SOUTHEASTERLY SURFACE WINDS...AND INCREASING MID LEVEL CLOUDS
MOVING IN FROM THE WEST/SOUTHWEST. LOW TEMPERATURES ARE EXPECTED TO
BE IN THE 20S.
.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 337 AM CST MON NOV 23 2015
THE FOCUS IN THE LONG TERM IS ON LIGHT SNOW POTENTIAL CENTERED ON
WEDNESDAY. WE ARE BECOMING MORE CONFIDENT THAT ACCUMULATIONS WILL
BE RELATIVELY LOW WITH THIS EVENT...POTENTIALLY LIMITING IMPACTS.
THE 00 UTC MODEL SUITE WAS IN RELATIVELY GOOD AGREEMENT IN SHOWING
LIGHT SNOW DEVELOPING IN WESTERN ND BY EARLY WEDNESDAY MORNING AND
SPREADING EASTWARD DURING THE DAY. THE MULTI-MODEL CONSENSUS CALLS
FOR LIQUID-EQUIVALENT MOISTURE VALUES OF 0.05 TO 0.15 INCHES /MOST
IN FAR SOUTHWESTERN ND/...WHICH SHOULD CONTRIBUTE TO SNOW AMOUNTS
RANGING FROM LESS THAN ONE-HALF INCH TO THE NORTH AND EAST OF THE
MISSOURI RIVER...TO 1 TO 2 INCHES SOUTH AND WEST OF THE MISSOURI
RIVER. OUR OFFICIAL FORECAST PRODUCED 3 INCH SNOW TOTALS ONLY IN
EXTREME SOUTHWESTERN ND...BOWMAN AND SLOPE COUNTIES...WEDNESDAY
THROUGH WEDNESDAY NIGHT.
THE SNOW WILL BE GENERATED IN A POST-FRONTAL ENVIRONMENT...DRIVEN
MAINLY BY DYNAMICS ASSOCIATED WITH A SHORTWAVE TROUGH EMBEDDED IN
THE NORTHERN STREAM OF A SPLIT FLOW. THE 03 UTC SREF LINGERED THE
SNOW LONGER THAN THE 00 UTC DETERMINISTIC GUIDANCE...SO A BIT OF
UNCERTAINTY REMAINS...BUT IN GENERAL GUIDANCE CONTINUED TO SUGGEST
THAT THE PRIMARY VERTICAL MOTION ASSOCIATED WITH THE 500-MB LOW IN
THE GREAT BASIN WILL REMAIN DISPLACED SOUTH OF ND. IF THAT IS THE
CASE...THANKSGIVING DAY MAY END UP COLD...BUT DRY IN MOST AREAS.
ONE OTHER ISSUE WE WILL NEED TO CONSIDER IS WHETHER FOG DEVELOPS
TUESDAY NIGHT...AND WHETHER LINGERING WARM AND DRY AIR ALOFT IS
CAPABLE OF PRODUCING ANY LIGHT FREEZING RAIN OR LIGHT FREEZING
DRIZZLE TUESDAY NIGHT INTO WEDNESDAY MORNING. FORECAST SOUNDINGS
ARE NOT PARTICULARLY SUGGESTIVE OF THAT POTENTIAL THOUGH...SO WE
ARE NOT MESSAGING THAT RISK AT THIS POINT.
A REX BLOCK WILL DEVELOP ALOFT OVER THE WESTERN UNITED STATES BY
NEXT WEEKEND AS THE GREAT BASIN LOW GETS PINCHED OFF TO THE SOUTH
OF A DEVELOPING 500-MB RIDGE OVER WESTERN CANADA. THIS SCENARIO IS
EXPECTED TO GENERATE A WARMING TREND AND MAINLY DRY WEATHER ACROSS
THE AREA NEXT WEEKEND...THOUGH THE 00 UTC GFS /AND THE 00 UTC GFS
ALONE/ DOES SUGGEST SOME SNOW POTENTIAL RETURNING NEXT SUNDAY WHEN
IT BREAKS THE BLOCK DOWN AND KICKS THE REMNANT LOW ALOFT EASTWARD
FURTHER NORTH THAN THE REST OF THE 00 UTC MODEL GUIDANCE.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z TUESDAY MORNING)
ISSUED AT 635 AM CST MON NOV 23 2015
VFR CONDITIONS EXPECTED UNTIL AROUND 02Z-06Z MONDAY EVENING...WHEN
INCREASING LOW CLOUDS WILL RESULT IN MVFR CIGS AT ALL TAF SITES.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...CJS
SHORT TERM...JV
LONG TERM...CJS
AVIATION...JV
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
207 AM EST MON NOV 23 2015
.SYNOPSIS...
A HIGH AMPLITUDE UPPER TROUGH EXTENDING FROM CENTRAL CANADA TO
THE EASTERN U.S. WILL BRING MAINLY DRY CONDITIONS AND BELOW
NORMAL TEMPERATURES THROUGH TUESDAY. A GRADUAL WARMUP AND
CONTINUED DRY WEATHER WILL FOLLOW FOR WEDNESDAY THROUGH FRIDAY AS
A LARGE AREA OF HIGH PRESSURE DRIFTS EAST AND OFF THE MID ATLANTIC
SEABOARD. A COLD FRONT WILL MOVE SOUTHEAST ACROSS THE STATE LATE
FRIDAY INTO SATURDAY WITH THE NEXT CHANCE OF RAIN
SHOWERS...CHANGING TO SCATTERED SNOW SHOWERS ON SATURDAY.
&&
.NEAR TERM /UNTIL 8 AM THIS MORNING/...
A LOW PWAT AIR MASS...RELATIVELY LOW SUBSIDENCE INVERSION HGTS OF
JUST 4-5 KFT AGL OR SO...AND LIMITED MFLUX OFF OF LK ERIE FROM
CROSS LAKE/NWRLY FLOW WILL LEAD TO CLOUDS AND THE LIKELIHOOD OF
MAINLY LIGHT SNOW SHOWERS ACROSS WARREN AND MCKEAN COUNTIES EARLY
TODAY... WHILE SKIES ACROSS MUCH OF THE REST OF THE REGION WILL
BE CLEAR TO PARTLY CLOUDY.
05Z HRRR SHOWS ALMOST NO MEASURABLE SNOW FALLING FROM THE
GENERALLY SHALLOW STRATO CU DECK ACROSS THE NW MTNS...THOUGH SFC
OBS BENEATH THIS CLOUD SHIELD /SUCH AS KELZ/ SUGGESTS THAT
ADDITIONAL LIGHT ACCUMS OF SNOW /ANOTHER COATING TO 1.5 INCHES/
COULD OCCUR THIS MORNING INVOF KBFD AND AREAS TO THE WEST ACROSS
WARREN COUNTY.
LOW TEMPS EARLY THIS MONDAY SHOULD DIP INTO THE UPPER TEENS
ACROSS SOME NORTHERN AND WESTERN MTN LOCATIONS...WITH THE REST OF
THE REGION SEEING MINS IN THE 20S.
&&
.SHORT TERM /8 AM THIS MORNING THROUGH 6 PM TUESDAY/...
A WEAK CLIPPER WILL MOVE QUICKLY SE FROM THE UPPER GLAKES THIS
AFTERNOON INTO TUESDAY. WAA AHEAD OF THIS SYSTEM COULD PRODUCE A
BIT OF LGT SNOW/FLURRIES THIS EVENING...MAINLY OVR THE NW MTNS.
BLEND OF LATEST MDL OUTPUT SUPPORTS NOTHING MORE THAN A FRESH
DUSTING OVER THE NW COUNTIES.
HIGH TEMPS THIS AFTERNOON WILL RANGE FROM NEAR 32F OVR THE HIGHER
TERRAIN OF NRN AND WRN PENN...TO THE LOWER 40S ACROSS THE
SOUTHEAST PART OF OUR CWA.
IN GENERAL...WINDS SHOULD BE FAIRLY LIGHT BENEATH SFC RIDGE AS IT
SLIDES EAST ACROSS PENN TODAY. HOWEVER...BUFKIT SUGGESTS SW WINDS
COULD GUST AS HIGH AS 20KTS ACROSS THE W MTNS LATE TODAY...AS
THE LLVL P-GRADIENT TIGHTENS BETWEEN WEAK LOW PRESSURE OVR THE
GRT LKS...AND HIGH PRES OVR THE SOUTHERN STATES.
&&
.LONG TERM /TUESDAY NIGHT THROUGH SUNDAY/...
A MODERATION OF TEMPERATURES WILL BE STARTING NEAR THE BEGINNING
OF THE LONG TERM PERIOD AS UPPER PATTERN TRANSITIONS TOWARD MORE
ZONAL FLOW EARLY IN THE WEEK...THEN SOUTHWESTERLY FLOW IN RISING
HEIGHTS IN RESPONSE TO A DIGGING UPPER TROF OVER THE WESTERN U.S.
INTERMOUNTAIN REGION.
AT THE SURFACE HIGH PRESSURE WILL DOMINATE OUR WEATHER TUESDAY TO
FRIDAY...THE CENTER OF THE HIGH WILL DRIFT OVER THE WESTERN
ATLANTIC...THE PATTERN IMPLIES LOW-LEVEL TRAPPED COLD AIR AS WARM
AIR BUILDS IN ALOFT AND A RIDGE BUILDS AT 500 MB TO OUR WEST. A
WARM LOOKING PATTERN ABOVE THE SURFACE. THE DEEP SOUTHWEST FLOW
IMPLIES INCREASED CHANCE RAIN TOWARD THE WEEKEND BUT NOTHING AT
THIS TIME TO FOCUS ON.
THE 850 MB TEMPERATURES WILL BE A BIT ABOVE NORMAL BY
THANKSGIVING AND PERHAPS INTO EARLY SATURDAY. LOTS OF UNCERTAINTY
AND SOME GEFS AND NAEFS MEMBERS SHOW COLD AIR SAGGING SOUTH
FRIDAY-SATURDAY. SO THE GEFS SHOWS SLIGHTLY ABOVE NORMAL
TEMPERATURES WED-FRIDAY BUT LATE FRIDAY-SATURDAY THE 2M
TEMPERATURE PLUMES SHOW HUGE SPREAD AND LOTS OF UNCERTAINTY. WILL
IT GET WARM OR A SHALLOW FRONT SLIDE THROUGH? INITIALLY THE MEDIAN
IS HIGHER THEN THE MEAN...FRIDAY SHOULD BE WARM...SATURDAY THE
MEDIAN IS BELOW THE MEAN...SATURDAY HIGHER PROBABILITY OF BEING
COLDER THAN FORECAST AS WE TEND TO THE MEAN.
&&
.AVIATION /07Z MONDAY THROUGH FRIDAY/...
FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT
ISSUED AT 134 AM EST MON NOV 23 2015
IR SATELLITE LOOP SHOWS AREA OF MVFR TO LOW VFR CIGS COVERING THE
NW 1/3 OF THE AIRSPACE PUSHING SOUTHEAST APPROACHING FIG/UNV/IPT.
LIGHT SNOW SHOWERS/FLURRIES MAY ALSO EXPAND ACROSS THIS AREA BUT
ISOLD VIS RESTRICTIONS SHOULD BE LIMITED TO MVFR. EXPECT LINGERING
SNOW TO DIMINISH BY THE AFTERNOON WITH MAINLY VFR CONDITIONS. SFC
WINDS 8-10KTS FROM 280-320 DEGREES THROUGH THE AFTERNOON /GUSTS
15-20KTS AT MDT-LNS/ WILL DECREASE AND BACK TO 200-250 DEGREES BY
TONIGHT. VFR SHOULD PREVAIL AT MOST SITES OVERNIGHT BUT MVFR CIGS
COULD RETURN TO THE NW AIRSPACE BY EARLY TUESDAY MORNING.
OUTLOOK...TUESDAY-FRIDAY
TUE...MVFR CIGS AND SCATTERED SNOW SHOWERS PSBL NW.
WED...VFR/NO SIG WX EXPECTED.
THU...LOW CIGS PSBL/NO SIG WX EXPECTED.
FRI...VFR/MVFR WITH RAIN SHOWERS PSBL MAINLY FRIDAY NIGHT.
&&
.CLIMATE...
UPDATED AT 210 AM EST MON NOV 23 2015
WITH 8 DAYS LEFT IN THE MONTH...PRELIMINARY CLIMATE DATA
INDICATES THAT NOVEMBER 2015 CURRENTLY RANKS AS THE WARMEST
NOVEMBER ON RECORD AT OUR TWO LONG TERM CLIMATE SITES: HARRISBURG
AND WILLIAMSPORT. A CONTINUOUS WEATHER RECORD HAS BEEN KEPT AT
EACH SITE SINCE 1888 AND 1895 RESPECTIVELY.
THROUGH 11/22...
THE AVG. MONTHLY TEMPERATURE AT HARRISBURG IS 52.2 DEGREES OR
+6.6 DEGREES ABOVE NORMAL.
THE AVG. MONTHLY TEMPERATURE AT WILLIAMSPORT IS 50.0 DEGREES OR
+6.9 DEGREES ABOVE NORMAL.
THE TOP 5 WARMEST NOVEMBERS (8 DAYS LEFT FOR 2015)
MDT: 2015 (52.2), 1931 (51.3), 1975 (50.0), 1999 (49.3), 1994
(49.0)
IPT: 2015 (50.0), 1931 (48.8), 1902 (47.3), 2009/1972 (47.2),
1913 (46.3)
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...LA CORTE/LAMBERT
NEAR TERM...FITZGERALD/LAMBERT
SHORT TERM...FITZGERALD/LA CORTE
LONG TERM...LAMBERT/GARTNER
AVIATION...STEINBUGL
CLIMATE...STEINBUGL
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
200 AM EST MON NOV 23 2015
.SYNOPSIS...
A HIGH AMPLITUDE UPPER TROUGH EXTENDING FROM CENTRAL CANADA TO
THE EASTERN U.S. WILL BRING MAINLY DRY CONDITIONS AND BELOW
NORMAL TEMPERATURES THROUGH TUESDAY. A GRADUAL WARMUP AND
CONTINUED DRY WEATHER WILL FOLLOW FOR WEDNESDAY THROUGH FRIDAY AS
A LARGE AREA OF HIGH PRESSURE DRIFTS EAST AND OFF THE MID ATLANTIC
SEABOARD. A COLD FRONT WILL MOVE SOUTHEAST ACROSS THE STATE LATE
FRIDAY INTO SATURDAY WITH THE NEXT CHANCE OF RAIN
SHOWERS...CHANGING TO SCATTERED SNOW SHOWERS ON SATURDAY.
&&
.NEAR TERM /UNTIL 8 AM THIS MORNING/...
A LOW PWAT AIR MASS...RELATIVELY LOW SUBSIDENCE INVERSION HGTS OF
JUST 4-5 KFT AGL OR SO...AND LIMITED MFLUX OFF OF LK ERIE FROM
CROSS LAKE/NWRLY FLOW WILL LEAD TO CLOUDS AND THE LIKELIHOOD OF
MAINLY LIGHT SNOW SHOWERS ACROSS WARREN AND MCKEAN COUNTIES EARLY
TODAY... WHILE SKIES ACROSS MUCH OF THE REST OF THE REGION WILL
BE CLEAR TO PARTLY CLOUDY.
05Z HRRR SHOWS ALMOST NO MEASURABLE SNOW FALLING FROM THE
GENERALLY SHALLOW STRATO CU DECK ACROSS THE NW MTNS...THOUGH SFC
OBS BENEATH THIS CLOUD SHIELD /SUCH AS KELZ/ SUGGESTS THAT
ADDITIONAL LIGHT ACCUMS OF SNOW /ANOTHER COATING TO 1.5 INCHES/
COULD OCCUR THIS MORNING INVOF KBFD AND AREAS TO THE WEST ACROSS
WARREN COUNTY.
LOW TEMPS EARLY THIS MONDAY SHOULD DIP INTO THE UPPER TEENS
ACROSS SOME NORTHERN AND WESTERN MTN LOCATIONS...WITH THE REST OF
THE REGION SEEING MINS IN THE 20S.
&&
.SHORT TERM /8 AM THIS MORNING THROUGH 8 AM TUESDAY/...
A WEAK CLIPPER WILL MOVE QUICKLY SE FROM THE UPPER GLAKES THIS
AFTERNOON INTO TUESDAY. WAA AHEAD OF THIS SYSTEM COULD PRODUCE A
BIT OF LGT SNOW/FLURRIES THIS EVENING...MAINLY OVR THE NW MTNS.
BLEND OF LATEST MDL OUTPUT SUPPORTS NOTHING MORE THAN A FRESH
DUSTING OVER THE NW COUNTIES.
HIGH TEMPS THIS AFTERNOON WILL RANGE FROM NEAR 32F OVR THE HIGHER
TERRAIN OF NRN AND WRN PENN...TO THE LOWER 40S ACROSS THE
SOUTHEAST PART OF OUR CWA.
IN GENERAL...WINDS SHOULD BE FAIRLY LIGHT BENEATH SFC RIDGE AS IT
SLIDES EAST ACROSS PENN TODAY. HOWEVER...BUFKIT SUGGESTS SW WINDS
COULD GUST AS HIGH AS 20KTS ACROSS THE W MTNS LATE TODAY...AS
THE LLVL P-GRADIENT TIGHTENS BETWEEN WEAK LOW PRESSURE OVR THE
GRT LKS...AND HIGH PRES OVR THE SOUTHERN STATES.
&&
.LONG TERM /TUESDAY THROUGH SUNDAY/...
A MODERATION OF TEMPERATURES WILL BE STARTING NEAR THE BEGINNING
OF THE LONG TERM PERIOD AS UPPER PATTERN TRANSITIONS TOWARD MORE
ZONAL FLOW EARLY IN THE WEEK...THEN SOUTHWESTERLY FLOW IN RISING
HEIGHTS IN RESPONSE TO A DIGGING UPPER TROF OVER THE WESTERN U.S.
INTERMOUNTAIN REGION.
AT THE SURFACE HIGH PRESSURE WILL DOMINATE OUR WEATHER TUESDAY TO
FRIDAY...THE CENTER OF THE HIGH WILL DRIFT OVER THE WESTERN
ATLANTIC...THE PATTERN IMPLIES LOW-LEVEL TRAPPED COLD AIR AS WARM
AIR BUILDS IN ALOFT AND A RIDGE BUILDS AT 500 MB TO OUR WEST. A
WARM LOOKING PATTERN ABOVE THE SURFACE. THE DEEP SOUTHWEST FLOW
IMPLIES INCREASED CHANCE RAIN TOWARD THE WEEKEND BUT NOTHING AT
THIS TIME TO FOCUS ON.
THE 850 MB TEMPERATURES WILL BE A BIT ABOVE NORMAL BY
THANKSGIVING AND PERHAPS INTO EARLY SATURDAY. LOTS OF UNCERTAINTY
AND SOME GEFS AND NAEFS MEMBERS SHOW COLD AIR SAGGING SOUTH
FRIDAY-SATURDAY. SO THE GEFS SHOWS SLIGHTLY ABOVE NORMAL
TEMPERATURES WED-FRIDAY BUT LATE FRIDAY-SATURDAY THE 2M
TEMPERATURE PLUMES SHOW HUGE SPREAD AND LOTS OF UNCERTAINTY. WILL
IT GET WARM OR A SHALLOW FRONT SLIDE THROUGH? INITIALLY THE MEDIAN
IS HIGHER THEN THE MEAN...FRIDAY SHOULD BE WARM...SATURDAY THE
MEDIAN IS BELOW THE MEAN...SATURDAY HIGHER PROBABILITY OF BEING
COLDER THAN FORECAST AS WE TEND TO THE MEAN.
&&
.AVIATION /07Z MONDAY THROUGH FRIDAY/...
FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT
ISSUED AT 134 AM EST MON NOV 23 2015
IR SATELLITE LOOP SHOWS AREA OF MVFR TO LOW VFR CIGS COVERING THE
NW 1/3 OF THE AIRSPACE PUSHING SOUTHEAST APPROACHING FIG/UNV/IPT.
LIGHT SNOW SHOWERS/FLURRIES MAY ALSO EXPAND ACROSS THIS AREA BUT
ISOLD VIS RESTRICTIONS SHOULD BE LIMITED TO MVFR. EXPECT LINGERING
SNOW TO DIMINISH BY THE AFTERNOON WITH MAINLY VFR CONDITIONS. SFC
WINDS 8-10KTS FROM 280-320 DEGREES THROUGH THE AFTERNOON /GUSTS
15-20KTS AT MDT-LNS/ WILL DECREASE AND BACK TO 200-250 DEGREES BY
TONIGHT. VFR SHOULD PREVAIL AT MOST SITES OVERNIGHT BUT MVFR CIGS
COULD RETURN TO THE NW AIRSPACE BY EARLY TUESDAY MORNING.
OUTLOOK...TUESDAY-FRIDAY
TUE...MVFR CIGS AND SCATTERED SNOW SHOWERS PSBL NW.
WED...VFR/NO SIG WX EXPECTED.
THU...LOW CIGS PSBL/NO SIG WX EXPECTED.
FRI...VFR/MVFR WITH RAIN SHOWERS PSBL MAINLY FRIDAY NIGHT.
&&
.CLIMATE...
UPDATED AT 138 AM EST SUN NOV 22 2015
WITH 9 DAYS LEFT IN THE MONTH...PRELIMINARY CLIMATE DATA
INDICATES THAT NOVEMBER 2015 CURRENTLY RANKS AS THE WARMEST
NOVEMBER ON RECORD AT OUR TWO LONG TERM CLIMATE SITES: HARRISBURG
AND WILLIAMSPORT. A CONTINUOUS WEATHER RECORD HAS BEEN KEPT AT
EACH SITE SINCE 1888 AND 1895 RESPECTIVELY.
THROUGH 11/21...
THE AVG. MONTHLY TEMPERATURE AT HARRISBURG IS 52.7 DEGREES OR
+6.9 DEGREES ABOVE NORMAL.
THE AVG. MONTHLY TEMPERATURE AT WILLIAMSPORT IS 50.4 DEGREES OR
+7.1 DEGREES ABOVE NORMAL.
THE TOP 5 WARMEST NOVEMBERS (CURRENT RANKINGS)
MDT: 2015 (52.7), 1931 (51.3), 1975 (50.0), 1999 (49.3), 1994
(49.0)
IPT: 2015 (50.4), 1931 (48.8), 1902 (47.3), 2009/1972 (47.2),
1913 (46.3)
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...LAMBERT
NEAR TERM...LAMBERT
SHORT TERM...LAMBERT/FITZGERALD
LONG TERM...LAMBERT/GARTNER
AVIATION...STEINBUGL
CLIMATE...STEINBUGL
AREA FORECAST DISCUSSION
NWS MILWAUKEE/SULLIVAN WI
320 PM CST MON NOV 23 2015
.TONIGHT - CONFIDENCE...MEDIUM.
PER WATER VAPOR/RAP LOOP BROAD MID/UPPER LEVEL ANTICYCLONIC FLOW
SHIFTING EASTWARD INTO WI. SFC/850 RIDGE AXES DRAW CLOSER WITH TIME
WHICH RESULTS IN GRADUAL EROSION OF THE LOW LEVEL THERMAL TROUGH SO
THINKING MUCH OF THE CLOUD COVER UPSTREAM ACROSS NRN MN AND NRN WI
WILL NOT MAKE IT INTO OUR AREA PLUS SOME OF THIS IS DIURNALLY DRIVEN
AS WELL. HOWEVER SREF CIG/VSBY PROGS ALONG WITH MET MOS ARE KEYING
ON SOME FOG/STRATUS DEVELOPMENT AS THE NIGHT WEARS ON AND THIS WOULD
MAKE THE MOST SENSE NEAR THE DEEPER SNOWFIELD ACROSS THE SRN CWA AND
IN CLOSER PROXIMITY TO ARRIVING LIGHTER WIND REGIME ASSOC WITH RIDGE
AXIS. VSBL SATELLITE ANIMATION DOES SHOW SOME EROSION OF THE
SNOWPACK FROM THE EDGES AND SOME THINNING FROM WITHIN. LLVL RH
PROGS/GFS MOS AND RAP SOUNDINGS ARE NOT TOO EXCITED ABOUT
STRATUS/FOG DEVELOPMENT AND WITH MAINLY CIRRUS UPSTREAM NOTHING.
HAVE ADDED PATCHY FOG IN THE SOUTHERN CWA AND BOOSTED SKY COVER A
BIT LATER IN THE NIGHT.
.TUESDAY - CONFIDENCE...MEDIUM
SFC RIDGE AXIS SHIFTS EAST. WITH LIGHT WIND REGIME EARLY WITH
SURFACE/850 RIDGE AXIS NEARBY ANY STRATUS/FOG EROSION MAY BE SLOW
UNTIL BETTER SOUTHERLY FLOW SETS UP. THIS RETURN FLOW WILL HELP TO
FURTHER MODIFY THE LOW LEVEL THERMAL PATTERN. HAVE BOOSTED TEMPS TO
ACCOUNT FOR ADDITIONAL EROSION IN SNOWCOVER AND 925 TEMPS INCHING
FURTHER ABOVE 0C ESP DURG THE AFTN WHEN SOUTHERLY FLOW RAMPS UP A
BIT MORE.
.TUESDAY NIGHT THROUGH THURSDAY - FORECAST CONFIDENCE...MEDIUM.
NO SIGNIFICANT CHANGES FOR THIS PERIOD. ZONAL STEERING FLOW
TRANSITIONS TO MORE SOUTHWEST FLOW AS LONG WAVE TROF
PROGRESSES SOUTHEAST ACROSS WESTERN CONUS. NORTHERN PORTION OF TROF
BREAKS AWAY AND BECOMES MORE PROGRESSIVE ACROSS NORTHERN CONUS WHILE
CUTOFF LOW LINGERS OVER WESTERN CONUS. AHEAD OF THIS APPROACHING
TROF...INCREASING SOUTHERLY WINDS IN THE LOW LEVELS WILL GRADUALLY
PULL DEEPER MOISTURE NORTHWARD INTO THE AREA BEGINNING WEDNESDAY.
COLUMN PWAT EXPECTED TO INCREASE TO OVER 1 INCH BY THU AFTN...WHICH
WOULD BE NEAR OR SLIGHTLY ABOVE THE RECORD PWAT FOR NORTHWEST IL PER
SPC SOUNDING CLIMATOLOGY AND STILL IN THE NEIGHBORHOOD OF 3
STANDARD DEVIATIONS FROM NORMAL.
MAIN PERIOD OF RAIN LIKELY TO BE LATER THURSDAY INTO THURSDAY NIGHT
WHEN DEEP MOISTURE WILL BE IN PLACE AND LOW LEVEL JET SURGES INTO
THE TRI-STATE AREA OF SRN WI/NRN IL AND ERN IA. IN ADDITION...RIGHT
ENTRANCE REGION OF UPPER JET PASSES ACROSS THIS SAME AREA DURING
THE PERIOD. OF SHORT TERM GUIDANCE...GFS REMAINS OUTLIER WITH MORE
PROGRESSIVE SOLUTION WITH STRONGEST SYNOPTIC FORCING JUST TO THE
SOUTH OF WI. 18Z NAM...GEH-NH AND ECMWF REMAIN FOCUSED FARTHER
NORTH SO ALONG WITH WPC...WILL LEAN ON THIS CONCENSUS WHICH
INCREASES THE THREAT FOR A PERIOD OF HEAVY RAINFALL ACROSS SRN WI ON
THU/THU NIGHT.
STILL THINKING 1-1.5 INCHES MAY FALL IN A 6 TO 12 HOUR PERIOD. BY
THAT TIME...THINKING THAT CURRENT SNOW COVER WILL BE CUT IN HALF DUE
TO GRADUAL MELTING THE NEXT FEW DAYS. THREAT FOR THICKER FOG AND
RELEASE OF LATENT HEAT OF CONDENSATION BEGINS WED NGT SO EXPECT SNOW
COVER TO BEGIN DECREASING MORE RAPIDLY THEN. GROUND NOT FROZEN AND
REMAINING SNOW SHOULD ABSORB SOME OF THE INITIAL RAIN. HOWEVER WITH
LINGERING SNOW ACROSS FAR SOUTHERN COUNTIES AND PERIOD OF HEAVY
RAIN...WOULD EXPECT RAPID RESPONDING RIVERS TO RISE THU
NGT...INCLUDING THE FOX AND PECATONICA RIVERS. THE ROCK RIVER WILL
ALSO LIKELY RESPOND BUT MORE SLOWLY IN ROCKCOUNTY. DUE TO THIS
THREAT...WL UPDATE HYDROLOGIC OUTLOOK STATEMENT.
.EXTENDED PERIOD...THURSDAY NIGHT THROUGH MONDAY...FORECAST
CONFIDENCE - MEDIUM TRENDING TO LOW.
WITH LARGE SCALE TROF SWEEPING EASTWARD ACROSS THE WESTERN GREAT
LAKES EARLY IN THE PERIOD AND WEAKER MID-LEVEL SHORT WAVE ENERGY
MOVING NORTHEAST ALONG BAROCLINIC ZONE DRAPED ACROSS SRN WI AND THE
ADJOINING REGION...WL CONTINUE CATEGORICAL POPS THURSDAY NIGHT.
CURRENTLY GFS OUTLIER WITH FASTER SOUTHEAST PROGRESS OF SFC FRONT
AND TIGHT BAROCLINIC ZONE THURSDAY NIGHT...WHICH WOULD HAVE GREATER
IMPACT ON LOW LEVEL THERMAL PROFILE. THIS WOULD INCREASE THE
PROBABILITY OF THE RAIN BECOMING MIXED WITH OR CHANGING OVER TO SNOW
ACROSS THE NORTHERN AND WESTERN CWA BEFORE THE PRECIP ENDS ON
FRIDAY. BOTH ECMWF AND GEM-NH SHOWING SLIGHTLY FASTER EWD
PROGRESSION AS WELL SO WL CONTINUE TO MENTION POTENTIAL FOR MIX OR
CHANGEOVER FROM WEST TO EAST 06Z-18Z FRI BEFORE PRECIP ENDS. NOT
EXPECTING ANY LAKE EFFECT OR ENHANCEMENT ON FRIDAY AS COLD AIR
SETTLES IN AS LOW LEVEL WINDS ANTICIPATED TO BE MORE NORTH TO
NORTHWEST WHILE DEEPER LOW LEVEL RH IS IN THE AREA. LOW LEVEL WINDS
DO VEER MORE NORTHEAST LATE FRI AND FRI NGT...HOWEVER LOW LEVEL
MOISTURE VERY LIMITED AT THIS TIME...AND WIND SPEEDS RAPIDLY
DIMINISH.
925H TEMPS FALL 10 TO 15C BY 00Z/SAT AND THESE COLDER TEMPERATURES
SHOULD REMAIN ENTRENCHED OVER SRN WI THROUGH THE WEEKEND INTO THE
FIRST DAYS OF DEC AS SHORT WAVE RIDGEING AND QUIETER CONDITIONS
AFFECT WISCONSIN. LATEST GFS MORE AGRESSIVE ON STRONGER PIECE OF
SHORT WAVE ENERGY MOVING NORTHEAST INTO THE CENTRAL MS VALLEY
INTO PARTS OF THE WESTERN GTLAKES ON MONDAY. ECMWF DOES SHOW
THIS STRENGTHENING LOW PRESSURE BUT WELL EAST AND SOUTH OF THE
REGION. WPC MEDIUM RANGE DESK TRENDING AWAY FROM DETERMINISTIC GFS
EARLY NEXT WEEK AND LEANING MORE ON DRIER ECMWF AND ECMWF ENSEMBLE.
HENCE WL KEEP POPS LOW FOR THE MONDAY TIMEFRAME.
&&
.AVIATION/00Z TAFS/...PRONOUNCED DRYING UPSTREAM PER VSBL SATELLITE
IMAGERY AND EXPECT QUIET CONDITIONS TO CONTINUE INTO TUESDAY WITH
HIGH PRESSURE RIDGE AXIS SLIDING INTO THE AREA TONIGHT AND THEN
SHIFTING OFF TO THE EAST ON TUESDAY. A LITTLE MORE UNCERTAINTY
ARISES LATER TONIGHT INTO TUESDAY MORNING. SREF CIG/VSBY PROG
SHOWING SOME HIGHER CONFIDENCE IN FOG/STRATUS DEVELOPMENT IN SRN WI
AS IS THE NAM MOS. TEMPS HAVE WARMED ABOVE FREEZING AND VSBL IMAGERY
SHOWS SOME MELTING HAS OCCURRED TODAY SO AS RIDGE AXIS DRAWS CLOSER
SOME FOG/STRATUS DEVELOPMENT POSSIBLE LATER TONIGHT INTO TUESDAY
MORNING...ESPECIALLY NEAR THE DEEPER SNOWCOVER IN FAR SRN WI.
&&
.MKX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
LM...NONE.
$$
TONIGHT AND TUESDAY/AVIATION...PC
TUESDAY NIGHT THROUGH MONDAY...MBK
AREA FORECAST DISCUSSION
NWS QUAD CITIES IA IL
329 AM CST WED NOV 25 2015
.SYNOPSIS...
ISSUED AT 329 AM CST WED NOV 25 2015
SATELLITE FOG CHANNEL IMAGERY EARLY THIS MORNING SHOWED A LARGE
TONGUE OF STRATUS ASSOCIATED WITH MOISTURE ADVECTION LOCATED
FROM THE WESTERN GULF NORTHWARD THROUGH OK...KS AND MO INTO
IA...REACHING INTO THE WESTERN HALF OF THE FORECAST AREA. THIS
WAS IN RESPONSE TO THE INCREASING SOUTHERLY FLOW BETWEEN HIGH
PRESSURE OVER THE MID ATLANTIC REGION AND DEVELOPING LOW PRESSURE
LEE OF THE ROCKIES. SOUTH TO SOUTHEAST WINDS HOLDING AROUND 10 TO
15 MPH ACROSS THE LOCATE AREA AT THE SURFACE WERE PROVIDING
ENOUGH LOW LEVEL MIXING TO NEGATE ANY THREAT OF FOG THIS
MORNING...AND ALSO HOLDING TEMPERATURES IN A RELATIVELY MILD RANGE
FROM THE MID 30S TO MID 40S.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 329 AM CST WED NOV 25 2015
INCREASING MOISTURE AND EVENTUAL MID LEVEL LIFT AS THE DEVELOPING
PLAINS FRONTAL SYSTEM APPROACHES WILL RESULT IN INCREASING
CLOUDS...AND EVENTUALLY LIGHT RAIN OR DRIZZLE OVER MUCH OF THE AREA
BY TONIGHT. THE BEST POTENTIAL FOR FOG NOW LOOKS TO BE LATER TONIGHT
AND TONIGHT...MAINLY OVER THE DEEPEST SNOWFIELDS AND WHERE LOW LEVEL
MOISTURE BEGINS TO CONVERGE AHEAD OF THE APPROACHING FRONT.
TODAY...BASED ON THE RATE OF MOISTURE RETURN...WITH SURFACE
DEWPOINTS IN THE 40S AND 50S STILL WELL TO THE SOUTH...THE DELAY IN
THE ONSET OF RAIN CHANCES TO MAINLY AFTERNOON INTO EVENING SHOWN BY
THE 06Z NAM LOOKS REASONABLE. THUS HAVE SLIGHT CHANCE POPS FOR LIGHT
RAIN DEVELOPING IN THE FAR NW THIS MORNING...THEN INCREASING POPS
FOR LIGHT RAIN OR DRIZZLE FROM NW TO SE DURING THE AFTERNOON AS
DEEPER SATURATION OCCURS ALONG WITH INCREASING MID LEVEL LIFT AHEAD
OF A WEAK SHORTWAVE IN THE SW FLOW ALOFT. THE POTENTIAL FOR FOG
DURING THE DAY LOOKS LIMITED TO THE FAR NORTH AND NW OVER THE DEEPER
REMAINING SNOW AND WHERE ANY WEAK LOW LEVEL MOISTURE CONVERGENCE
IS MAXIMIZED. QPF AMOUNTS WILL BE LESS THAN A TENTH OF AN INCH.
TEMPERATURES WILL CONTINUE TO GRADUALLY RISE...DESPITE MOST SITES
BECOMING OVERCAST BY MID MORNING. HIGHS BY LATE AFTERNOON WERE
KEPT IN A RANGE FROM THE LOWER 40S NORTH TO THE MID 50S IN THE FAR
SOUTH.
TONIGHT...MODEL CONSENSUS HAS THE DEVELOPING PLAINS COLD FRONT
APPROACHING FROM THE WEST...IN A SW TO NE ORIENTATION...APPROACHING
INDEPENDENCE AFTER 12Z. AN INCREASING MOISTURE FEED AHEAD OF THIS
BOUNDARY...LOW LEVEL CONVERGENCE...AND LIFT FROM MID LEVEL WAVES IN
THE SW FLOW WILL LEAD TO WIDESPREAD RAIN OVER THE AREA. ANY FOG WILL
AGAIN BE MOST LIKELY HELD TO THE NORTH AND NW THE FORECAST
AREA...BUT THIS IS NOT LIKELY TO BE DENSE DURING THIS PERIOD. QPF
AMOUNTS WILL STILL BE RATHER LIGHT...WITH UP TO A QUARTER INCH IN
THE FAR NW...IN THE STRONGEST FORCING AND CONVERGENCE...TO A FEW
HUNDREDTHS OF AN INCH IN THE EAST AND SE. THE MOIST AIRMASS AND
BRISK SOUTHERLY LOW LEVEL FLOW WILL KEEP TEMPERATURES NEARLY
STEADY THROUGH THE NIGHT IN THE 40S AND 50S.
.LONG TERM...(THURSDAY THROUGH TUESDAY)
ISSUED AT 329 AM CST WED NOV 25 2015
MAIN FORECAST CONCERN IN THE LONG TERM ARE NUMEROUS CHANCES FOR
PRECIPITATION...IN THE FROZEN AND LIQUID FORM...DURING THIS BUSY
HOLIDAY WEEKEND. AT THIS TIME IT APPEARS THAT DURING THANKSGIVING
AND INTO FRIDAY ALL PRECIP WILL BE LIQUID...AFTER THIS...FOR THE
WEEKEND IT BECOMES MORE TRICKY. FROZEN PRECIP COULD BE POSSIBLE AT
NIGHT WITH LIQUID DURING THE DAY AS MODELS AGAIN ARE STRUGGLING WITH
THE CLOSED LOW/BLOCKING PATTERN OVER THE ROCKIES.
THANKSGIVING THROUGH FRIDAY AFTERNOON...
RAIN SHOULD BE ONGOING AT THE BEGINNING OF THE PERIOD. LOW LEVEL
OMEGA AND ISENTROPIC ASCENT SUGGESTS THAT MOST OF THE HEAVIEST
PRECIP WILL BE WEST OF THE RIVER AT 12Z. LIGHT RAIN COULD BE ONGOING
ACROSS THE AREA...HOWEVER THE STRONGEST RAIN WILL BE LOCATED WITH
THE RISING MOTION ASSOCIATED WITH THE FRONT AS LARGE SCALE VORTICITY
ADVECTION IS WEAK. THE 00Z NAM 4KM SHOWS A LINE OF MODERATE
RAINSHOWERS... VIRTUALLY COLLOCATED WITH THE FRONT. THIS MODEL
DEPICTS THE BAND OF RAIN ENTERING OUR CWA AROUND 18Z AND MARCHING
THROUGH THE AREA AND EXITING BY 09Z FRIDAY. RAINFALL TOTALS OF 1 TO
2 INCHES ARE POSSIBLE WITH THE HIGHEST AMOUNTS LOCATED ALONG A LINE
FROM DBQ TO CID TO MARENGO. IT IS SAFE TO SAY THAT THANKSGIVING WILL
BE WET ACROSS OUR AREA. AS THE FRONT MOVES THROUGH THE
AREA....LINGERING PRECIP WILL ENCOUNTER COLD AIR AT THE LOW LEVELS.
WITH LARGE SCALE FLOW STILL OUT OF THE SW...A 1044 HPA HIGH TRIES TO
BUILD INTO THE AREA. IT WILL BE INTERESTING TO SEE HOW DEEP THE
COLD DOME IS AS MODELS SUGGEST A MODEST WARM NOSE ALOFT AS THE COLD
AIR MOVES INTO THE LOW LEVELS. IN THIS SITUATION...PRECIP ON THE
BACK END...ESPECIALLY NORTH OF A LINE FROM MARENGO TO DUBUQUE
COULD TRANSITION OVER TO FZRA AND THEN TO SLEET AND EVEN POSSIBLY
SN. MY CONFIDENCE IS LOW IN THIS OCCURRING...AS SUCH ADDED SCHC
FZRA AND PL ACROSS THIS AREA IN THE NORTHWEST. AT THIS TIME...DO
NOT EXPECT ANY ICE OR SN ACCUMULATIONS FRI AM. ANYTHING THAT DID
FALL WOULD MELT AS HIGHS ARE FORECAST TO BE ABOVE FREEZING FRIDAY
AFTERNOON.
FRIDAY EVENING THROUGH MONDAY MORNING...
A HIGH OVER LOW BLOCK ACROSS THE WESTERN UNITED STATES PROVIDES
MODELS WITH A TRICKY FORECAST FOR THE WEEKEND. AS THIS IS A BUSY
TRAVEL WEEKEND...THE MODEL DISCREPANCIES HAVE MY CONFIDENCE IN THE
FORECAST VERY LOW. THE GFS HAS A WAVE THAT PUSHES THE LOW TO EAST
FASTER THAN THE ECMWF. HOWEVER...THE ECMWF SLOWLY LUMBERS THE LOW
TOWARDS US AT THE SAME TIME. MODEL CONSENSUS FORECAST MOVES THE
1040+ HIGH THROUGH THE AREA QUICKLY THIS WEEKEND AS SW LOW LEVEL
FLOW ADVECTS MOISTURE BACK INTO THE AREA. THIS MEANS THAT THE
CHANCE FOR PRECIP RETURNS TO THE AREA SATURDAY THROUGH NEXT WEEK.
THIS WEEKEND IT LOOKS AS THOUGH SOME WINTRY MIX WILL FALL AT NIGHT
WITH RAIN DURING THE DAY. THIS WILL LEAD TO DIFFICULT FORECAST
ALONG WITH POSSIBLE TRAVEL ISSUES COME THIS WEEKEND ACROSS OUR AREA.
THOSE TRAVELING BACK OR THROUGH THE AREA THIS WEEKEND SHOULD PAY
ATTENTION TO FUTURE FORECASTS.
MONDAY ON...
MAJOR DIFFERENCES IN THE MODELS MAKE IT DIFFICULT TO HAVE ANY
CONFIDENCE IN THE FORECAST. WHAT ADDS TO THIS DIFFICULTY IS THE
PROXIMITY OF THE FREEZING LINE....THROUGH OUR CWA AT NIGHT AND JUST
NORTH DURING THE DAY. THERMAL PROFILES MAKE IT DIFFICULT TO DISCERN
WHAT TYPE OF FROZEN PRECIP IS EXPECTED. IF THE LOW STARTS TO MOVE
FROM THE BLOCKING PATTERN THEN INEVITABLY THIS FORECAST WILL BECOME
SLIGHTLY EASIER...UNTIL THEN OR THE MODELS AGREE ON A SOLUTION NO
CHANGES WILL BE MADE TO THE CURRENT BLENDED FORECAST. EXPECT
SPECIFICS TO CHANGE FOR THE SYSTEMS NEXT WEEK.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT)
ISSUED AT 1131 PM CST TUE NOV 24 2015
MAIN ITEM OVERNIGHT AND THROUGH DAYBREAK IS LOW LEVEL WIND SHEAR.
KDVN VWP LAST 1-2 HRS HAS BEEN SHOWING 45 KTS AT 2KFT WHICH
VERIFIES RAP AND NAM SOUNDINGS... THUS CONTINUED MENTION OF
LLWS THROUGH ABOUT 14-15Z WEDNESDAY WITH SURFACE WINDS S/SE
AROUND 10-15 KTS. SOME PATCHY FOG IS STILL POSSIBLE TOWARD
DAYBREAK BUT CONFIDENCE DIMINISHING DUE TO WELL MIXED BOUNDARY
LAYER AND INCREASING CLOUDS. WILL SEE STRATUS OVERSPREAD THE
TERMINALS OVERNIGHT AND WEDNESDAY AM... WITH INITIALLY VFR CIGS
IN RANGE OF 3500-5000FT AGL. IN TIME WITH ARRIVAL OF BETTER LOW
LEVEL MOISTURE AND DEEPER SATURATION LATER IN THE DAY WEDNESDAY
AND WEDNESDAY NIGHT EXPECT TO SEE CIGS LOWER TO MVFR ESPECIALLY AT
KCID AND KDBQ WITH PATCHY DRIZZLE OR VERY LIGHT RAIN MAY OCCUR
WITHIN WHERE BEST MOISTURE TRANSPORT IS DEPICTED. THERE IS A
CHANCE OF SOME IFR CONDITIONS DEVELOPING AT KDBQ AND KCID LATE IN
THE TAF CYCLE...BUT CONFIDENCE TOO LOW FOR MENTION THIS FAR OUT.
HAVE ALSO MENTIONED MVFR CIGS AT KBRL AND KMLI BY WEDNESDAY
EVENING WITH LAMP AND GFS/NAM MOS GUIDANCE IN AGREEMENT...
HOWEVER SREF CIG HEIGHT PROBS VERIFYING PRETTY WELL LATE THIS
EVENING AND WOULD ACTUALLY SUPPORT BETTER POTENTIAL MAINLY TO
NORTH/WEST OF KBRL AND KMLI... WHICH IS SOMETHING TO MONITOR IN
LATER TAF ISSUANCES.
&&
.HYDROLOGY...
ISSUED AT 329 AM CST WED NOV 25 2015
LONG DURATION RAINFALL EVENT THROUGH THANKSGIVING AND INTO FRIDAY
MORNING COULD BRING RAINFALL AMOUNT FROM 1 TO 2 INCHES ACROSS THE
AREA. WITH SNOWPACK STILL ON THE GROUND...A LARGE PERCENTAGE OF
THIS STEADY RAIN COULD GO STRAIGHT TO RUNOFF. ENSEMBLE RIVER
FORECASTS SUGGEST RIVER FLOODING WHEN THE HIGHEST QPF IS USED. WHEN
USING QPF CLOSE TO WHAT IS FORECAST A FEW RIVERS GET TO ACTION
STAGE. CURRENT FORECASTS FOR KALONA AND MARENGO TAKE THESE SITES TO
FLOOD. AT THIS TIME...MY CONFIDENCE IN THIS OCCURRING AND THE
FORECAST QPF OCCURRING IS LOW. WE COULD GET ROBBED OF MOISTURE FROM
THE CONVECTION TO OUR SOUTH. WITH SUCH LOW CONFIDENCE IN THE QPF
FORECAST DECIDED TO HOLD OFF ON A FLOOD WATCH AND ISSUING FLOOD
WARNINGS FOR MARENGO AND KALONA.
&&
.DVN WATCHES/WARNINGS/ADVISORIES...
IA...NONE.
IL...NONE.
MO...NONE.
&&
$$
SYNOPSIS...SHEETS
SHORT TERM...SHEETS
LONG TERM...GIBBS
AVIATION...MCCLURE
HYDROLOGY...GIBBS
AREA FORECAST DISCUSSION
NWS QUAD CITIES IA IL
1145 PM CST TUE NOV 24 2015
.SYNOPSIS...
ISSUED AT 330 PM CST TUE NOV 24 2015
OTHER THAN PATCHY TO AREAS OF THIN CIRRUS...SKIES WERE SUNNY
ACROSS THE DVN CWA. MID AFTERNOON TEMPERATURES WERE IN THE MID TO
UPPER 30S ALONG HIGHWAY 20 WHERE THE DEEPEST SNOW COVER EXISTS...
TO THE LOWER 50S SOUTH OF HIGHWAY 34 WITH BARE GROUND.
&&
.SHORT TERM...(THIS EVENING THROUGH WEDNESDAY)
ISSUED AT 330 PM CST TUE NOV 24 2015
FORECAST FOCUS ON POTENTIAL FOR FOG AND CHANCE OF LIGHT RAIN ON
WEDNESDAY.
TONIGHT...A VEIL OF THICKENING CIRRUS WILL COVER THE CWA AS A
SHORT WAVE IN THE CENTRAL PLAINS MOVES ACROSS THE AREA IN THE
SOUTHWEST FLOW ALOFT. ALONG WITH SOUTHEAST TO SOUTH WINDS THIS
WILL MEAN TEMPERATURES WILL BE MUCH WARMER THAN THE PAST SEVERAL
NIGHTS. THE AIRMASS WILL STILL BE RATHER DRY SO BELIEVE FOG THAT
FORMS AFTER MIDNIGHT SHOULD REMAIN ON THE PATCHY SIDE. MINIMUM
TEMPERATURES WILL RANGE FROM THE LOWER 30S ALONG HIGHWAY 20 TO THE
UPPER 30S IN OUR FAR SOUTHERN CWA.
WEDNESDAY...SOUTHERLY WINDS WILL TRANSPORT INCREASING LOW LEVEL
MOISTURE FROM THE WESTERN GULF AS HIGH PRESSURE SITS OVER THE
SOUTHEAST UNITED STATES...AND A CLOSED LOW MOVES INTO NEVADA.
FORECAST SOUNDINGS INDICATE PWATS INCREASE TO 0.60 TO 0.80 INCHES
BY LATE AFTERNOON. WITH THE DETERMINISTIC MODELS SHOWING A 40 KNOT
LOW LEVEL JET FROM TX TO IA I DON`T SEE ANY REASON TO DISAGREE.
WITH THIS MOISTURE AND A COLD FRONT APPROACHING FROM THE WEST
THERE WILL BE A CHANCE OF SOME LIGHT RAIN OR DRIZZLE...MAINLY IN
THE AFTERNOON AND NEAR AND WEST OF THE MS RIVER. SKIES WILL ALSO
BECOME CLOUDY AS MODELS SPREAD/DEVELOP LOW STRATUS ACROSS THE CWA
DUE TO THE INCREASING LOW LEVEL MOISTURE...AND IT`S NOVEMBER.
MAXIMUM TEMPERATURES ARE EXPECTED TO RANGE FROM THE MID 40S ALONG
HIGHWAY 20 TO THE LOWER 50S IN OUR SOUTHERN CWA. HAASE
.LONG TERM...(WEDNESDAY NIGHT THROUGH NEXT TUESDAY)
ISSUED AT 330 PM CST TUE NOV 24 2015
WEDNESDAY NIGHT AND THURSDAY...STRENGTHENING AND DEEP
SOUTHWESTERLIES ON BACKSIDE OF LARGE ATLANTIC COAST RIDGE TO WARM-
MOIST ADVECT STRONGLY WED NIGHT...WITH PWAT/S PROJECTED TO SATURATE
TO 0.80 TO AROUND AND INCH BY DAYBREAK THU. MORE OF THE 12Z RUN
MODEL SOLUTIONS CONTINUE TO ADJUST WEST WITH MAIN NE-TO-SW ORIENTED
SFC FRONT ALIGNING UNDER THE FLOW...MAKING FOR MORE LLVL CONVERGENT
RAIN PRODUCTION/COVERAGE ACRS THE FAR NORTHWESTERN CWA LATE WED
NIGHT. THIS CONVERGENT AREA WHERE WINDS DROP OFF MAY BE WHERE THE
AREAS OF FOG FORM AFTER MIDNIGHT AS WELL. OTHERWISE THE REST OF THE
CWA JUST INCREASING PATCHY AREAS OF LIGHT RAIN OR DRIZZLE WITH A
SOUTH SFC BREEZE OF 10-15 MPH MAKING FOR STEADY TO SLOWLY RISING
TEMPS INTO THU MORNING. SEASONABLY STRONG WARM MOIST CONVEYOR IN
FULL SWING ON THU AND THU NIGHT EVENING...WITH THE MODELS HAVING
INCREASED PWATS TO VERY HIGH LEVELS FOR LATE NOVEMBER AND FROM
PREVIOUS RUNS...GENERALLY 1.1 TO 1.4 INCHES. THIS KIND OF SATURATION
COMBINED WITH DEEP VERTICAL LAYER POS OMEGAS EASILY SUPPORT A BAND
OF MODERATE RAINS RIDING UP ALONG THE FRONT AND POST-
FRONTALLY...SLOWLY PUSHING FROM WEST-TO-EAST THU INTO FRI MORNING
BEFORE CLEARING OFF TO THE EAST ACRS MOST OF THE AREA BY FRI
AFTERNOON. FURTHER WEST FRONTAL ADJUSTMENT SUPPORTS THE MOST
WIDESPREAD RAIN COVERAGE ALONG AND WEST OF THE MS RVR THROUGH 00Z
FRI...THEN PUSHING EAST THU NIGHT AND WILL BLANKET THE CWA WITH
HIGH/CATEGORICAL POPS ACCORDINGLY.
AGAIN BACK TO THE UNSEASONABLE SATURATION COMBINED WITH DURATION OF
LIFT...STILL SEE THE CWA GETTING WIDESPREAD 1-2 INCHES BY FRI
MORNING WHEN IT TAPERS OFF. BUT WILL ADJUST THE HEAVY RAINFALL AXIS
FURTHER WEST WITH LATEST THINKING AND ADVERTISE 1.5 TO 1.8+ INCHES
WEST OF A LINE FROM FREEPORT IL...TO THE QUAD CITIES AND TO KEOKUK
IA ON SOUTH ALONG THE MS RVR. 12-18 HOURS FOR THIS RAIN TO FALL WILL
HELP...BUT WILL CONTINUE TO TOUCH UPON THE ALREADY SATURATED
SOILS/SNOW MELT MAKING FOR MORE RUN-OFF THAN WHAT OCCURRED FOR AN
EVEN STRONGER EVENT BACK A WEEK AGO ON NOV 17TH. THUS SOME RIVER
LEVELS COULD REALLY COME UP TO BANKFULL OR EVEN FLOOD STAGE THROUGH
THE WEEKEND. DESPITE THE CLOUDS/PRECIP/SATURATION...A MILD TURKEY
DAY AHEAD OF THE FRONT WITH HIGHS IN THE MID 50S TO AROUND 60 ACRS
THE SOUTHEAST HALF OF THE FCST AREA...40S TO LOW 50S TO THE WEST OF
THAT UNLESS THE FRONT SLOWS MORE.
THE 12Z RUNS SUGGEST MARGINAL IN-WRAPPING LLVL COLD CONVEYOR AND
EVENTUAL TOP-DOWN COOLING ABOVE THAT PROCESS FOR A PRECIP SWITCH TO
SLEET OR FREEZING RAIN BRIEFLY ACRS THE FAR NORTHWESTERN CWA LATE
THU NIGHT...THEN TO A RAIN-SNOW MIX INTO FRI MORNING. FOR NOW WILL
ADVERTISE LESS THAN AN INCH OF WET SNOW ACCUM BY FRI MORNING
WEST/NORTHWEST OF THE CEDAR RAPIDS AREA. THE LLVLS MAY STAY WARM
ENOUGH FOR ALL RAIN ARRIVAL AT THE SFC ACRS THE EASTERN THIRD OF THE
DVN CWA THU NIGHT INTO FRI AM.
FRIDAY THROUGH SUNDAY...LATEST SUITE OF MEDIUM RANGE MODELS IN MORE
DISAGREEMENT IN HANDLING A SOUTHERN STREAM SYSTEM EJECTING OF OF THE
SOUTHERN PLAINS AND UP TOWARD THE REGION...BATTLING WESTERN GRT LKS
RIDGING AS IT DOES. TAKING A GENERAL ENSEMBLE BLEND...IT SUGGESTS
THAT A PRECIP SHIELD OFF THIS POTENTIAL SYSTEM MAY SPREAD UP ACRS THE
SOUTHERN 2/3S OF THE CWA FROM LATE SAT AND INTO SUNDAY. THE 12Z GFS
IS MILDER WITH IT/S LOW TO MID LEVEL THERMAL PARAMETERS AND SUGGESTS
MAINLY A OVERRUNNING LIGHT TO MODERATE RAIN EVENT ALONG AND SOUTH OF
THE HWY 30 CORRIDOR WITH RAIN ENDING BY LATE SUNDAY MORNING. THE
12Z ECMWF SUGGESTS A WINTRY MIX OF SLEET/FREEZING RAIN...THEN A
SWITCH OVER TO WET SNOW UP ALONG AND NORTH OF THE I80 CORRIDOR SAT
NIGHT...LINGERING LONGER INTO SUNDAY BUT SWITCHING OVER TO MAINLY A
COLD RAIN WITH COLUMN MODERATION ALOFT. WILL GO WITH HIGHER POPS
SOUTH AND ADVERTISE A RAIN-SNOW MIX IN THE NORTH FOR NOW...FURTHER
DEFINING PRECIP TYPES OVER THE NEXT SEVERAL DAYS AS WE GET CLOSER TO
THE PRECIP EVENT. HIGHS IN THE UPPER 30S TO 40S SAT INTO SUNDAY...
WITH LOWS AT NIGHT IN THE 20S TO LOWER 30S POSSIBLY BEING TOO COLD.
EARLY NEXT WEEK...THE MEDIUM RANGE SOLUTIONS STILL SUGGEST A CLOSED
UPPER LOW WITH VARYING THERMAL PROFILES DEPENDING ON THE MODEL...
ROLLING SLOWLY ACRS THE MIDWEST FOR OCCASIONAL PRECIP CHANCES FROM
LATE MONDAY THROUGH AT LEAST TUE NIGHT. ..12..
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT)
ISSUED AT 1131 PM CST TUE NOV 24 2015
MAIN ITEM OVERNIGHT AND THROUGH DAYBREAK IS LOW LEVEL WIND SHEAR.
KDVN VWP LAST 1-2 HRS HAS BEEN SHOWING 45 KTS AT 2KFT WHICH
VERIFIES RAP AND NAM SOUNDINGS... THUS CONTINUED MENTION OF
LLWS THROUGH ABOUT 14-15Z WEDNESDAY WITH SURFACE WINDS S/SE
AROUND 10-15 KTS. SOME PATCHY FOG IS STILL POSSIBLE TOWARD
DAYBREAK BUT CONFIDENCE DIMINISHING DUE TO WELL MIXED BOUNDARY
LAYER AND INCREASING CLOUDS. WILL SEE STRATUS OVERSPREAD THE
TERMINALS OVERNIGHT AND WEDNESDAY AM... WITH INITIALLY VFR CIGS
IN RANGE OF 3500-5000FT AGL. IN TIME WITH ARRIVAL OF BETTER LOW
LEVEL MOISTURE AND DEEPER SATURATION LATER IN THE DAY WEDNESDAY
AND WEDNESDAY NIGHT EXPECT TO SEE CIGS LOWER TO MVFR ESPECIALLY AT
KCID AND KDBQ WITH PATCHY DRIZZLE OR VERY LIGHT RAIN MAY OCCUR
WITHIN WHERE BEST MOISTURE TRANSPORT IS DEPICTED. THERE IS A
CHANCE OF SOME IFR CONDITIONS DEVELOPING AT KDBQ AND KCID LATE IN
THE TAF CYCLE...BUT CONFIDENCE TOO LOW FOR MENTION THIS FAR OUT.
HAVE ALSO MENTIONED MVFR CIGS AT KBRL AND KMLI BY WEDNESDAY
EVENING WITH LAMP AND GFS/NAM MOS GUIDANCE IN AGREEMENT...
HOWEVER SREF CIG HEIGHT PROBS VERIFYING PRETTY WELL LATE THIS
EVENING AND WOULD ACTUALLY SUPPORT BETTER POTENTIAL MAINLY TO
NORTH/WEST OF KBRL AND KMLI... WHICH IS SOMETHING TO MONITOR IN
LATER TAF ISSUANCES.
&&
.DVN WATCHES/WARNINGS/ADVISORIES...
IA...NONE.
IL...NONE.
MO...NONE.
&&
$$
SYNOPSIS...HAASE
SHORT TERM...HAASE
LONG TERM...12
AVIATION...MCCLURE
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
1236 AM EST WED NOV 25 2015
.SHORT TERM...(THIS EVENING THROUGH WEDNESDAY)
ISSUED AT 332 PM EST TUE NOV 24 2015
12Z RAOBS/LATEST WV IMAGERY AND RAP ANALYSIS SHOW AN UPR RDG OVER
THE PLAINS EXPANDING INTO THE GREAT LKS. 00Z-12Z H5 HGT RISES OVER
MUCH OF THE W HALF OF THE GREAT LKS WERE AOA 100M AND AS MUCH AS
130M AT APX AND DTX. THE 12Z INL/GRB/APX RAOBS SHOW SHARP SUBSIDENCE
INVRN IN THE H8-85 LYR. DESPITE TEMPS AT THIS ELEVATED INVRN BASE AS
LO AS -10C...RATHER DRY NATURE OF THE SUB INVRN LYR AS DEPICTED ON
THE INL AND GRB RAOBS HAS GREATLY RESTRICTED LES EVEN OVER THE E...
WHERE THE LLVL NW FLOW WAS WEAKLY CYC THIS MRNG AHEAD OF A WEAK SFC
RDG AXIS OVER THE WRN CWA EXTENDING TO THE N OF STRONGER HI CENTER
IN THE TN RIVER VALLEY. THE LO CLDS HAVE BROKEN UP SOMEWHAT WITH THE
ARRIVAL OF THE SFC RDG OVER THE W AND SCENTRAL. EVEN WHERE THE LO
CLDS HAVE DSPTD...A GOOD AMOUNT OF MID/UPR LVL MSTR ASSOCIATED WITH
STRONGER WAA IN THE NRN PLAINS IS SUPPORTING AREA OF MID/HI CLDS
SPILLING OVER THE RDG INTO THE WRN LKS.
MAIN FCST CONCERNS IN THE SHORT TERM FOCUS ON THE IMPACT OF
STRENGTHENING SLY FLOW THAT IS FCST TO DEVELOP TNGT/WED BETWEEN SFC
HI PRES RDG FCST TO MOVE E/BUILD UNDER THE EXPANDING UPR RDG AND
FALLING MSLP IN THE PLAINS TO THE E OF A DEEPENING TROF OVER THE W.
TNGT...SFC HI PRES SHIFTING E INTO NEW ENGLAND/MID ATLANTIC STATES
IS FCST TO BUILD TO ABOUT 1040MB BY 12Z WED. IN CONCERT WITH DVLPG
LO PRES TROF ALONG THE BORDER BTWN MN AND THE DAKOTAS...THE PRES
GRADIENT OVER THE WRN GREAT LKS IS FCST TO TIGHTEN CONSIDERABLY...
WITH S H925 WINDS INCRSG UP TO 35-40KTS ACCENTUATED BY DVLPG PRES
FALL CENTER OVER NW ONTARIO. MODELS SHOW AN AXIS OF HIER RH IN THE
SFC-H9 LYR RETURNING INTO THE CENTRAL CWA OVERNGT WITHIN THIS
STRENGTHENING SLY FLOW AND UNDER LINGERING LARGER SCALE SUBSIDENCE
INVRN. WITH AN UPSOPE LLVL SSE FLOW... MAINTAINED SOME FCST -DZ/
-FZDZ IN THIS AREA. LIMITED DEPTH OF RETURNING MOIST LYR AND/OR
DOWNSLOPE FLOW WL RESULT IN A DRY FCST FOR THE REST OF THE CWA. LO
TEMPS MAY BE TRICKY TNGT...ESPECIALLY OVER THE E. IF THE LO CLDS
LINGERING THERE DSPT THIS EVNG WITH THE PASSING OF THE SFC HI/MORE
ACYC FLOW BEFORE THE SLY FLOW PICKS UP...TEMPS COULD FALL QUICKLY
BEFORE WINDS PICK UP OVERNGT. SUSPECT THE LO CLDS WL BE RESILIENT
ENUF AND INCOMING MID/HI CLDS WL LIMIT THIS EVNG TEMP DROP...SO DID
NOT GO TOO LO WITH FCST MIN TEMPS. INCRSG S WINDS/MORE CLDS WL
LIKELY BRING RISING TEMPS OVERNGT.
WED...STEADY/GUSTY S SLOWLY VEERING SW LLVL FLOW IS FCST TO SLOWLY
INCRS MSTR DEPTH THRU THE DAY. IN CONCERT WITH SOME WEAK DEEP LYR
QVECTOR CNVGC ASSOCIATED WITH THE LARGER SCALE WAA/ISENTROPIC
ASCENT...THERE MAY BE SOME LIGHT RA OR DZ. BUT GENERAL DRYNESS OF
THE FCST AIRMASS IN THE MID LVLS/DGZ AND ONLY WEAK FORCING SUGGESTS
ANY PCPN WL BE ON THE LGT SIDE. SO MODEL QPF IS RATHER LGT AND
SPOTTY AND FOCUSED MAINLY AWAY FM THE DOWNSLOPE AREAS NEAR LK SUP.
ALTHOUGH THE CLDS WL HOLD DOWN MAX TEMPS...READINGS NOT FAR FM 40 WL
STILL BE WELL ABOVE NORMAL.
.LONG TERM...(WEDNESDAY NIGHT THROUGH TUESDAY)
ISSUED AT 416 PM EST TUE NOV 24 2015
BY 00Z THURSDAY THE INITIAL N END OF THE ELONGATED SFC TROUGH WILL
BE SET UP FROM N ONTARIO THROUGH THE W HALF OF LAKE
SUPERIOR...EXTENDING IN THE FORM OF A COLD FRONT DOWN THROUGH KS TO
THE S LOW OVER NE NM. THE NAM IS HINTING AT SOME ENHANCEMENT TO THE
PRECIP ACROSS THE N CENTRAL HIGHER TERRAIN AREAS FROM BIG BAY
THROUGH NEGAUNEE/ISHPEMING TO GWINN WEDNESDAY EVENING.
THE N END OF THE BROAD 500MBTROUGH STRETCHING FROM N CENTRAL CANADA
DOWN TO THE MAIN LOW MOVING ON SHORE IN OR/N CA THIS AFTERNOON WILL
KEEP A CUT OFF LOW SPINNING OVER THE W THIRD OF THE NATION THROUGH AT
LEAST THE FIRST HALF OF THE UPCOMING WEEKEND.
LOOK FOR THE COLD FRONT TO SWEEP TO THE E HALF OF UPPER MI BY
DAYBREAK THURSDAY. AS THE N END OF THE 500MB TROUGH SHIFTS ACROSS
MANITOBA TO E MT. WILL KEEP THE FREEZING DRIZZLE/DRIZZLE POTENTIAL
GOING OVERNIGHT WEDNESDAY NIGHT THROUGH THURSDAY MORNING...BEFORE
BETTER MOISTURE SNEAKS IN. THURSDAY AFTERNOON AND EVENING WILL BE
THE LARGEST THREAT PERIOD FOR MAINLY CENTRAL AND E UPPER MI...WITH A
SMALL CHANCE OF SLEEP S CENTRAL THURSDAY AFTERNOON INTO THE
EARLY EVENING HOURS. ELSEWHERE...SNOW SHOULD BE ON THE
DOORSTEP...CHANGING OVER TO ALL SNOW W THURSDAY MORNING AND HOLDING
OFF FAR E UNTIL THURSDAY EVENING. THE CANADIAN AND ECMWF ARE STILL
MORE ROBUST ON THE W PRECIP PUSH. THE OVERALL PICTURE IS
SIMILAR...MAKING THE FCST TRICKY. THE 12Z ECMWF DID COME IN WITH A
LITTLE LESS PRECIP THOUGH OVER CENTRAL UPPER MI...IN SOME PLACES
CLOSE TO 0.2IN LESS. A BLENDED SOLUTION STILL LOOKS GOOD...WITH A
SLANT TOWARDS THE ECMWF SOLUTION AS IT BEGINS TO COME MORE IN LINE
WITH THE GFS.
THE 500MB TROUGH AND COLDEST 850MB TEMPS OF -5 TO -8C TRAVERSES
UPPER MI FRIDAY...WITH THE GFS STILL THE MOST PROGRESSIVE. THE
FAVORABLE N-NNW SNOW WINDS OFF LAKE SUPERIOR SLOWLY SWITCH TO A MORE
W DIRECTION LATER FRIDAY WITH SNOW ENDING W TO E AS HIGH PRESSURE
BUILDS INTO THE REGION.
THE LARGE 500MB LOW OVER THE W U.S. BEGINS TO SHIFT ACROSS THE N AND
CENTRAL PLAINS LATE SUNDAY THROUGH MONDAY...BEFORE MOVING TO THE
UPPER GREAT LAKES TUESDAY. THE GFS IS MORE PROGRESSIVE THAN THE
ECMWF...WITH A NEARLY STACKED SFC-500MB LOW SPINNING ACROSS THE N/WI
BORDER BY 12Z TUESDAY. THE 00Z ECMWF SOLUTION WAS MORE WRAPPED UP
BUT WITH LESS MOISTURE AVAILABLE AND A WEAKER SFC REFLECTION. THE
SFC HIGH REMAINED STRONG OVER THE REGION THROUGH...WITH 12-24 HOUR
SLOWER RESPONSE COMPARED TO THE GFS. THE 12Z ECMWF CAME IN MUCH MORE
IN LINE WITH THE 12Z GFS WITH THE NEXT SFC LOW OVERHEAD AT 12Z
MONDAY. WILL SEE IF THIS BETTER CONSISTENCY CAN HOLD UP THROUGH THE
NEXT COUPLE OF DAYS.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT)
ISSUED AT 1235 AM EST WED NOV 25 2015
AN INCREASING S WIND TONIGHT WILL RESULT IN IN LLWS OVERNIGT AND
DRAW MOISTER AIR INTO THE WESTERN GREAT LAKES. THIS WILL BRING
DETERIORATING CONDITIONS IN THE PRESENCE OF NOCTURNAL COOLING. THE
BEST CHANCE FOR A SUSTAINED PERIOD OF LOWER END MVFR TO IFR
CONDITIONS WILL BE AT KSAW...WHERE THE EXPECTED SSE WIND WILL
UPSLOPE. DOWNSLOPE NATURE OF THE EXPECTED FLOW AT KIWD AND KCMX MAKE
IFR CIGS LESS LIKELY. MVFR CONDITIONS ARE LIKELY TO DROP TO IFR WED
EVENING AS ADDITIONAL MOISTURE ALONG WITH SOME LIGHT RAIN OR DRIZZLE
MOVE IN.
&&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 332 PM EST TUE NOV 24 2015
RELATIVELY LIGHT WINDS THIS EVENING WILL BECOME S AND INCREASE
QUICKLY OVERNIGHT UNDER TIGHTENING PRES GRADIENT BETWEEN BUILDING HI
PRES TO THE E AND FALLING PRES IN THE PLAINS. OPTED TO UPGRADE GALE
WATCH FOR MUCH OF THE E HALF TO A WARNING FOR WED INTO THE
EVENING...WHEN THE GRADIENT/WINDS WILL DIMINISH SUFFICIENTLY. EXPECT
A WIND SHIFT TO THE NNW AFTER A COLD FRONT CROSSES THE LAKE ON WED
NIGHT INTO EARLY THU. THE TIGHT PRES GRADIENT AHEAD OF TRAILING HI
PRES WILL LEAD TO WINDS UP TO 30 KTS AND PERHAPS SOME MARGINAL GALE
FORCE WINDS INTO THU NIGHT. WINDS WILL THEN SLOWLY DIMINISH INTO FRI
AS THIS HI PRES EDGES CLOSER. ALTHOUGH W WINDS COULD INCREASE UP TO
25-30KT AGAIN ON SAT UNDER A TIGHTENING GRADIENT BETWEEN THE HI
CENTERED JUST TO THE SW AND ANOTHER LO PRES TROF SWINGING THRU
NORTHERN ONTARIO...A WEAKER GRADIENT AND LIGHTER WINDS ARE EXPECTED
TO PREVAIL ON SUN AFTER THE TROF EXITS INTO QUEBEC AND THE HI PRES
RIDGE BUILDS BACK TOWARD THE UPPER LAKES.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
GALE WARNING FROM 7 AM THIS MORNING TO 10 PM EST THIS EVENING
FOR LSZ266-267.
LAKE MICHIGAN...
GALE WARNING FROM 10 AM THIS MORNING TO 1 AM EST THURSDAY FOR
LMZ248-250.
&&
$$
SHORT TERM...KC
LONG TERM...KF
AVIATION...JLB
MARINE...KC
AREA FORECAST DISCUSSION
NWS NORTH PLATTE NE
340 AM CST WED NOV 25 2015
.SYNOPSIS...
ISSUED AT 340 AM CST WED NOV 25 2015
A CONVOLUTED H5 PATTERN CONTINUES TONIGHT ACROSS NOAM WITH A
RIDGE EXTENDING FROM THE NE PACIFIC INTO THE GULF OF ALASKA.
DOWNSTREAM OF THE RIDGE...A TROUGH EXTENDED FROM NRN SASKATCHEWAN
INTO NRN CALIFORNIA. AT THE BASE OF THIS TROUGH...CLOSED LOW
PRESSURE WAS NOTED OVER SWRN OREGON. EAST OF THE TROUGH...A ZONAL
PATTERN EXISTED ACROSS THE REMAINDER OF THE LOWER 48 STATES WITH
THE EXCEPTION OF A PERSISTENT TROUGH WHICH EXTENDED FROM EASTERN
QUEBEC...SWD INTO NEW ENGLAND. AT THE SURFACE...A FRONTAL
BOUNDARY WAS ANCHORED ALONG THE NEBR/SD BORDER AND MARKED THE
LEADING EDGE OF ARCTIC AIR WHICH WAS ENTRENCHED ACROSS THE NRN
PLAINS. READINGS OFF TO THE NORTH WERE IN THE TEENS IN MONTANA
WITH BREEZY NORTHERLY WINDS. SOUTH OF THE FRONT...TEMPERATURES
WERE IN THE 20S TO LOWER 30S WITH THE EXCEPTION SERN NEBRASKA
WHERE 40S AND LOWER 50S WERE COMMON THANKS TO LOW CLOUDS AND A
DECENT INFLUX OF LOW LEVEL MOISTURE PUSHING NORTH FROM EASTERN
KANSAS. FOR NOW...THE STRATUS AND LOW LEVEL MOISTURE HAS STAYED
JUST OFF TO THE EAST AND SOUTHEAST OF THE FORECAST AREA AND
SHOULD REMAIN THERE BASED ON THE LATEST HRRR FORECAST.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 340 AM CST WED NOV 25 2015
FOR TODAY AND TONIGHT...THE MAIN FORECAST CHALLENGE WILL BE THE
THREAT FOR A WINTRY MIX OF PCPN BEGINNING TONIGHT. FOR
TODAY...THE ARCTIC COLD FRONT WILL PUSH SOUTH THIS MORNING AND
WILL CLEAR MOST OF THE FORECAST AREA BY MID AFTERNOON. HIGHS
TODAY WILL STRUGGLE TO GET OUT OF THE 30S IN THE
NORTHWEST...WHILE 40S ELSEWHERE REMAIN ON TRACK FOR THE FORECAST.
LIKE YESTERDAY...THERE WAS A LARGE DISPARITY IN HIGH TEMPERATURES
BETWEEN THE MAV AND MET GUIDANCE. THE MET SEEMED TOO COOL FOR
NORTH PLATTE TODAY WITH ITS HIGH OF 38 GIVEN THE LATER FRONTAL
TIMING OF EARLY AFTERNOON AND TRENDED THE TEMP FORECAST MORE
TOWARD THE WARMER MAV GUIDANCE. HOWEVER DID NOT GO WITH HIGHS AS
WARM AS THE MAV GUIDANCE SUGGESTS. THIS WAS DUE TO AN ABUNDANCE
OF MID AND HIGH LEVEL CLOUD COVER EXPECTED TODAY IN ADVANCE OF
THE APPG COLD FRONT.
TONIGHT...LOW LEVEL MOISTURE WILL INCREASE BEHIND THE EXITING
COLD FRONT AS A SHIELD OF STRATUS DEVELOPS ACROSS WESTERN AND
NORTH CENTRAL NEBRASKA. ABOVE THE STRATUS...A DECENT DRY LAYER
WILL EXIST WITH SOME WEAK LIFT NOTED JUST ABOVE THE STRATUS LAYER
OVERNIGHT. A THOROUGH EXAMINATION OF BUFKIT FORECAST SOUNDINGS
INDICATES A DECENT SETUP FOR FREEZING DRIZZLE TONIGHT...ROUGHLY
EAST OF A LINE FROM SPRINGVIEW TO OGALLALA. WEST OF THIS
LINE...TEMPERATURE PROFILES IN THE MOIST LAYER SEEM TOO COLD FOR
THE DEVELOPMENT OF FREEZING DRIZZLE AND HAVE OPTED FOR A MENTION
OF SNOW AS THERE IS SOME INDICATION OF MID LEVEL
MOISTENING...ESPECIALLY OVER NORTHWESTERN PORTIONS OF THE CWA
OVERNIGHT. EVEN WITH THE MID LEVEL MOISTENING...THE BEST MOISTURE
IS NOT COLLOCATED WITH THE BEST DENDRITIC TEMPERATURES...SO ANY
SNOW WILL BE VERY LIGHT IN NATURE. ACROSS THE FAR SOUTHEASTERN
CWA...TEMPS WILL BE WARM TO SUPPORT DRIZZLE OR VERY LIGHT RAIN
EARLY THIS EVENING...FOLLOWED BY AREAS OF FREEZING DRIZZLE
OVERNIGHT. LOW LEVEL MOISTURE WILL BE MOST FAVORABLE FOR MORE
WIDESPREAD FREEZING DRIZZLE OVERNIGHT ACROSS FRONTIER AND FAR
SERN CUSTER COUNTY OVERNIGHT...AS IT FLOWS NORTH INTO NEBRASKA
FROM KANSAS. WITH THIS IN MIND...HAVE DECIDED TO PLACE FRONTIER
COUNTY IN A WINTER WEATHER ADVISORY AS QPF FORECASTS ARE
INDICATIVE OF UP TO A FEW HUNDREDTHS OF AN INCH OF FREEZING PCPN.
HOWEVER...ATTM...THE GREATEST THREAT FOR ACCUMULATING FREEZING
PCPN APPEARS TO BE WELL EAST OF THE FORECAST AREA MORE INTO
THURSDAY. WILL RUN THE ADVISORY FROM MIDNIGHT CST TONIGHT THROUGH
6 PM CST THURSDAY.
.LONG TERM...(THURSDAY THROUGH TUESDAY)
ISSUED AT 340 AM CST WED NOV 25 2015
THE THANKSGIVING HOLIDAY TRAVEL EXPECTED TO BE IMPACTED ACROSS
MUCH OF THE AREA. A UPPER LEVEL LOW CUTS OFF ACROSS SW CONUS WITH
A POSITIVELY TILTED TROUGH ACROSS THE NORTHERN PLAINS. AT THE SFC
A COLD FRONT WILL BE EAST OF THE CWA WITH ARCTIC HIGH PRESSURE
BUILDING ACROSS THE ROCKIES. THE MAIN CONCERN FOR THE DAY ON
THURSDAY WILL BE THE LOWER LEVEL TEMP PROFILE AND THE POCKET OF
MID LEVEL DRY AIR. THE LATEST MODELS HAVE TRENDED SLIGHTLY
FURTHER EAST WITH THE COLD AIR AND BUFKIT SOUNDINGS NOW
SUGGESTING BY 12Z THE LOWER PROFILE ALL BELOW ZERO C AND HAVE
FORECAST NOW ALL SNOW. LIFT IS MARGINAL AND WILL BATTLE A POCKET
OF DRY AIR...SO EXPECT SNOW TO BE LIGHT AND WILL HAVE TO MONITOR
THE LEVEL OF DRYNESS AS PRECIP COULD SEE A MIX OF FREEZING
DRIZZLE HOWEVER NOT MENTIONED AT THIS TIME. THROUGH THE DAY
ACCUMULATION WILL BE LIGHT...LESS THAN AN INCH. AS FOR
TEMPS...THE COLD AIR ADVECTION AND PERSISTENT CLOUDS WILL LIMIT
WARMING. GUIDANCE SUGGEST TEMPS REBOUND A FEW DEGREES...HOWEVER
WOULD NOT BE SURPRISED IF TEMPS HELD STEADY OR EVEN FELL DURING
THE AFTERNOON. STILL WELL BELOW NORMAL WITH HIGHS IN THE MID TO
UPPER 20S.
COLD HIGH PRESSURE BUILDS ACROSS THE NORTHERN CWA THURSDAY NIGHT
INTO FRIDAY. THIS WILL USHER IN SOME DRY AIR AND CONFINE ANY SNOW
ACTIVITY TO THE SOUTHERN CWA...WHICH MAY NEED TO BE PUSHED
FURTHER SOUTH PENDING STRENGTH OF THE HIGH. LOWS ON THE COLD
SIDE...SINGLE DIGITS AND TEENS...REBOUNDING ONLY TO THE
20S...MAYBE 30 FOR FRIDAY.
OVER THE WEEKEND THE LOW WILL LIFT NORTH ACROSS THE ROCKIES AS
THE SFC HIGH SHIFTS EAST. RECYCLED COLD AIR WILL WRAP AROUND THE
HIGH AND OVER THE AREA. ALSO GOING TO SEE THE DRY AIR GET PUSHED
EAST WITH A LITTLE BETTER MOISTURE AND A RETURN TO AT LEAST A
SLIGHT CHANCE FOR LIGHT SNOW. THE LATEST EC BROUGHT A DISTURBANCE
AHEAD OF THE UPPER LEVEL LOW AND PRODUCED A BRIEF PERIOD OF
MODERATE SNOW SATURDAY NIGHT. WILL KEEP POPS LOW FOR NOW AND MAKE
A NOTE TO WATCH CAREFULLY.
EARLY NEXT WEEK THE UPPER LOW WILL SLIDE EAST ACROSS THE NORTHERN
PLAINS. COLD AIR REMAINS IN PLACE...HOWEVER COULD SEE SOME MORE
SUN AND HIGHS REBOUNDING INTO THE 30S. A CHANCE FOR SNOW MONDAY
REMAINS IN THE FORECAST...HOWEVER AS THE UPPER LEVEL LOW PUSHES
EAST THE CHANCE FOR ANY PRECIP DIMINISHES THROUGH MID WEEK.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT)
ISSUED AT 1140 PM CST TUE NOV 24 2015
STRATUS WILL STAY TO THE EAST OF WESTERN NEBRASKA OVER NIGHT.
SOME OF THE STRATUS WILL FIND ITS WAY INTO CENTRAL NEBRASKA
THROUGH THE EARLY MORNING HOURS. COLD FRONT WILL CONTINUE TO MOVE
SOUTH OUT OF SOUTH DAKOTA INTO NORTHWEST NEBRASKA THROUGH THE
EARLY MORNING HOURS. WITH THE FRONT WEDNESDAY MORNING NORTHWEST
WINDS WILL INCREASE AND BECOME GUSTY. AREAS OF DRIZZLE WILL BE
POSSIBLE OVER NORTHWEST NEBRASKA THROUGH THE AFTERNOON AND COULD
AFFECT BOTH KVTN AND KLBF TAF SITES THROUGH THE EARLY EVENING.
CEILINGS WILL LOWER INTO MVFR CATEGORIES CIGS THROUGH THE
AFTERNOON AND THERE COULD BE SOME FREEZING DRIZZLE OVER NORTHERN
NEBRASKA AROUND 26/00Z.
&&
.LBF WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY FROM MIDNIGHT TONIGHT TO 6 PM CST
THURSDAY FOR NEZ071.
&&
$$
SYNOPSIS...BUTTLER
SHORT TERM...BUTTLER
LONG TERM...MASEK
AVIATION...POWER
AREA FORECAST DISCUSSION
NWS SIOUX FALLS SD
1053 PM CST TUE NOV 24 2015
.SHORT TERM...(THIS EVENING THROUGH WEDNESDAY)
ISSUED AT 239 PM CST TUE NOV 24 2015
MAIN CONCERNS TONIGHT INTO TOMORROW MOSTLY CENTERED AROUND
FOG/DRIZZLE THREAT. DEW POINTS IN THE MID 30S ACROSS EASTERN
NEBRASKA INTO EASTERN KANSAS THIS AFTERNOON WILL CONTINUE TO ADVECT
NORTHWARD TONIGHT. WITH AN INVERSION IN PLACE AND SNOW COVER THIS
SHOULD LEAD TOWARDS WIDESPREAD STRATUS AND FOG. DRIZZLE WILL ALSO BE
LIKELY...ESPECIALLY AHEAD OF THE INCOMING COLD FRONT. EXPECTING TO
SEE STRATUS AND FOG EXPAND IN COVERAGE FROM ABOUT 2Z THROUGH 9Z WITH
MOST LOCATIONS UNDER STRATUS OR FOG BY 12Z WEDNESDAY. FOR NOW NO
CONCERNS WITH FREEZING DRIZZLE AS IT APPEARS THAT ANY DRIZZLE SHOULD
OCCUR WITH TEMPERATURES MAINLY 34 OR WARMER. THE ONE AREA TO WATCH
MAY BE AROUND THE JAMES VALLEY OR JUST EAST OF THERE WHERE
TEMPERATURES COULD SNEAK DOWN TO 31 OR 32 BY SUNRISE AND CAUSE A
LITTLE FREEZING ON EXPOSED SURFACES AND UNTREATED ROADS. CONFIDENCE
TOO LOW TO INCLUDE AT THIS TIME AND BELIEVE THE THREAT WILL BE EAST
OF THE COLDER TEMPERATURES. WILL HAVE EARLY EVENING LOWS IN THE
EASTERN CWA WITH RISING TEMPERATURES BUT MORE STANDARD LOWS IN THE
WESTERN CWA.
REMOVED ANY MENTION OF RAINFALL FOR WEDNESDAY AS DRY AIR ALOFT WILL
KEEP THE THREAT TO DRIZZLE OR FOG. DO STILL HAVE SOME 20 POPS OVER
PARTS OF NORTHWEST IOWA AS THERE IS A CHANCE SOME OF THIS DRIZZLE
COULD PRODUCE A HUNDREDTH OR TWO TOMORROW AFTERNOON. OTHERWISE HIGHS
MAINLY IN THE UPPER 30S TO MID 40S.
.LONG TERM...(WEDNESDAY NIGHT THROUGH TUESDAY)
ISSUED AT 239 PM CST TUE NOV 24 2015
WEDNESDAY NIGHT WILL SEE SOME SPREAD OF LIGHT RAIN AND DRIZZLE NORTH
ACROSS NORTHWEST IA AND SOUTHWEST MN AS THE LOW LEVEL MOISTURE FLOW
GETS DEEPER. SOME FRONTAL LIFT OF THIS MOISTURE IS LIKELY AND HAVE
KEPT A CHANCE OF LIGHT PRECIPITATION...TENDING TO SNOW WITH THE
COOLING...OVER THE MISSOURI RIVER AREA ALL THE WAY TO CHAMBERLAIN.
SOME MIXED FREEZING RAIN AND SLEET ALSO POSSIBLE IN THE TRANSITION
AREA AS COOLING BEHIND THE FRONT PROGRESSES AND GETS DEEPER.
THANKSGIVING DAY WILL BRING CONTINUED STEADY COOLING WITH LIGHT
PRECIPITATION MAINLY SOUTHEAST HALF. THE PRECIPITATION WILL CONTINUE
TO TREND TO SNOW WITH A MIXTURE PRECEDING. THE PRECIPITATION THREAT
SHOULD PEAK AROUND THE MIDDLE OF THE DAY THEN BEGIN TO DECREASE FROM
THE WEST. GIVEN THE POSITIVE TILT NATURE OF THE SYSTEM AND FAIRLY
QUICK DRYING COMING IN BEHIND THE FRONT...LIKELY TO UNQUALIFIED POPS
WILL BE IN THE FORECAST ONLY FOR NORTHWEST IOWA INTO THE SOUTHEAST
CORNER OF SOUTHWEST MINNESOTA INCLUDING JACKSON. AT THIS TIME THE
SNOWFALL OUTLOOK IS AROUND 2 INCHES IN THIS AREA WITH LESS TO THE
WEST AND NORTH. WINDS WILL GET JUST A BIT ON THE STIFF SIDE BUT NOT
SEEN STRONG ENOUGH AT THIS TIME TO JUSTIFY A MENTION OF BLOWING SNOW
WITH THESE LIMITED AMOUNTS. THE PROBLEM WITH GETTING MORE IS THAT
THE SHORT WAVE COMING UP THE EAST SIDE OF THE SOUTHWESTERN UPPER LOW
IS GOING TO RUN INTO RIDGING FORCED BY THE NORTHERN STREAM WAVE
WHICH HELPS BRING IN THE COLDER AIR...SO THE WAVE WILL BE DAMPENED
OUT AS IT APPROACHES AND THE DECENT FRONTAL BANDING WILL NOT HAVE
MUCH TO WORK ON IT.
SNOW SHOULD MOVE OUT TO THE NORTHEAST OR SIMPLY DISSIPATE OVER THE
AREA THURSDAY NIGHT AND A COUPLE DAYS OF DRY AND COLD WEATHER WILL
ARRIVE. IT LOOKS LIKE THE MAIN UPPER LOW WILL APPROACH BY LATE IN
THE WEEKEND. MODELS DIFFER GREATLY NOT ONLY AMONG EACH OTHER BUT
FROM RUN TO RUN ON HANDLING THIS SYSTEM. A DECENT WAVE COMING UP
TOWARD THE AREA MAY TEND TO RAP BACK AROUND THE UPPER LOW. IN ANY
EVENT THERMAL CONTRAST LOOKS FAIR TO POOR IN THIS PATTERN...SO
DESPITE THE CONSIDERABLE UNCERTAINTY IN MODEL SOLUTIONS...DO NOT
LOOK FOR A BIG STORM THREAT AT THIS TIME. THE GFS SEEMS TO SERVE UP
THE BEST POTENTIAL OF A FEW INCHES OF SNOW WITH ITS POSITIONING OF
THE WAVE BY MONDAY.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT)
ISSUED AT 1047 PM CST TUE NOV 24 2015
MAIN CHANGE WAS TO SLOW DOWN THE ARRIVAL OF MVFR VISIBILITY AND
LOW STRATUS OVERNIGHT. WITH TEMPERATURES STAYING UP SO FAR THIS
EVENING AND A MORE SUBSTANTIAL DEWPOINT DEPRESSION THIS
EVENING...FOG IS SLOW TO DEVELOP. A BAND OF LOW END VFR STRATUS IS
LIFTING NORTHWARD INTO NORTHWEST IOWA...WHILE HIGH CLOUDS ARE
FILTERING INTO THE WESTERN FORECAST AREA. WHILE MODELS ARE SPLIT
ON THE FOG AND STRATUS POTENTIAL OVERNIGHT...DO THINK THAT THERE
IS ENOUGH OF A POTENTIAL LATER TONIGHT WITH INCREASING
DEWPOINTS...TO LEAVE MENTION OF LOWER VISIBILITY IN FSD AND SUX
AROUND 10 TO 12Z. WITH INCREASING MOISTURE...SOME LOWER STRATUS IS
ALSO LIKELY TO FORM LATE TONIGHT/WEDNESDAY MORNING. STILL A LOT OF
UNCERTAINTY IN TIMING FOR THE LOWER CEILINGS AND HOW LONG
IFR/MVFR CONDITIONS WILL PERSIST WEDNESDAY.
&&
.FSD WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
MN...NONE.
IA...NONE.
NE...NONE.
&&
$$
SHORT TERM...08
LONG TERM...
AVIATION...
AREA FORECAST DISCUSSION
National Weather Service Lincoln IL
524 AM CST WED NOV 25 2015
.SHORT TERM...(Today)
ISSUED AT 330 AM CST WED NOV 25 2015
The CWA is in between the high pressure to the east and the
developing weather system in the plains. In this position, breezy
southerly winds and warmer temperatures are to be expected today.
With the increasing waa ahead of the developing system, an increase
in low level moisture is occurring, which is will bring an increase
in cloud cover to the area. The increasing clouds could retard the
warming trend this afternoon, but believe the strong waa should be
able to compensate. So, am expecting skies to become mostly cloudy
today with highs in the 50s and southerly winds of 15 to 25 mph.
.LONG TERM...(Tonight through Tuesday)
ISSUED AT 330 AM CST WED NOV 25 2015
00Z models are similar with cold front moving east into the IL river
valley Thu night and across eastern IL Friday afternoon. Aloft,
strong 538 dm 500 mb low over northern CA into nw NV will move
across the central Rockies on Thu and remain near the Rockies this
weekend and eject ne into the Midwest and Great Lakes on Monday
night and Tue. This will likely bring an extended unsettled weather
pattern to IL with daily rain chances through early next week.
Chances of light rain showers moves into the IL river valley this
evening and deeper into central IL overnight while southeast IL
remains dry. Milder lows tonight in the upper 40s to around 50F with
clouds and breezy south winds. Clouds and breezy south winds
continue Thu with highs in the upper 50s and lower 60s. Rain chances
also increase to 60-80% nw of the IL river by Thu afternoon and 40-
50% over heart of central IL while only 20-30% in southeast IL and
near the IN border. Rainfall amounts even nw of the IL river appear
fairly light on Thu with highest amounts near a quarter inch by
Galesburg.
Increased lift with approaching cold front and deeper moisture to
bring highest rain chances Thu night into Friday along with heaviest
rainfall ranging from 1-1.5 inches with rain chances likely
lingering over southeast IL Friday night where storm total rainfall
of 1.50-1.75 inches. This may cause some rivers and streams to go
back to near flood especially at Clay City on the Little Wabash
river. Flash flood guidance is 1.5-2 inches per hour and 2-3 inches
in 6 hours so these rainfall amounts are still less than that and
will hold off on a flood watch.
Surface low pressure to lift ne along frontal boundary just
southeast of the Ohio river into nw KY by Sunday morning. This will
likely lift showers back ne into central IL during this weekend
especially Sat night into Sunday morning. Highest rain chances will
be over southeast IL along with heaviest rainfall amounts. Even
though temps cool by this weekend, they still appear warm enough to
support rain over our area. Lingered 20-30% chances of light rain
showers early next work week as upper level low moves into the area
and keeps it cloudier and cooler.
&&
.AVIATION...(For the 12Z TAFS through 12Z Thursday morning)
ISSUED AT 524 AM CST WED NOV 25 2015
Clear skies will give way to clouds around 5kft moving into the
area this morning. The clouds will begin in the west at SPI and
PIA, then spread east and reach CMI last. Based on satellite
trends and upstream observations, looks like heights will remain
VFR levels, around 3.5kft. The clouds will continue through the
day and into the night ahead of the next weather system. HRRR and
NAM12 bring some light/scattered pcpn into the area beginning
late this afternoon and into tonight. Given the waa and all the
clouds, though not that low, will go with VCSH at all TAF sites in
the new forecast for late this afternoon and into this evening.
Winds will be southerly through the period with daytime gusts to
around 25kts. Winds will decrease some during the evening, but
expecting gusts to continue.
&&
.ILX Watches/Warnings/Advisories...
NONE.
&&
$$
SHORT TERM...Auten
LONG TERM...07
AVIATION...Auten
AREA FORECAST DISCUSSION
NWS DES MOINES IA
556 AM CST WED NOV 25 2015
...UPDATED AVIATION DISCUSSION...
.SHORT TERM /TODAY/...
ISSUED AT 332 AM CST WED NOV 25 2015
DRIZZLE/RAIN/FOG POTENTIAL WERE THE MAIN CONCERNS FOR TODAY`S
FORECAST. A COUPLE SIGNIFICANT CHANGES...DELAYED THE ONSET OF
DRIZZLE UNTIL LATE MORNING/EARLY AFTERNOON AND THEN INCREASED POPS
LATE THIS AFTERNOON. LEANED TOWARD A RUC13/HRRR/SREF FOR TIMING OF
POPS TODAY.
THE STRATUS SHIELD CONTINUES TO ADVECT NORTHWARD AND WILL BLANKET
THE FORECAST AREA THROUGHOUT THE DAY TODAY. COLD FRONT LOOKS TO
CREEP INTO THE FAR NORTHWEST CORNER OF THE STATE LATER THIS AFTER
AFTERNOON AND THE LOW-LEVEL MOISTURE (BELOW 750MB) GRADUALLY
INCREASES DURING THE MORNING HOURS AND POOLS AHEAD OF THE FRONT OVER
CENTRAL IOWA BY THE AFTERNOON. THE MOISTURE ADVECTION IS SHOWN WELL
ON THE ISENTROPIC SURFACES FROM 290-300K. THE DRIZZLE REALLY
BLOSSOMS OVER CENTRAL IOWA BY AROUND 21Z AND THE LATEST HRRR
(25.05Z) HAS A GREAT HANDLE ON THIS TREND. DELAYED THE POPS OVER
MUCH OF THE FORECAST AREA UNTIL 17Z WITH A SLIGHT CHANCE ACROSS THE
SOUTHWEST B/T 15-17Z TODAY. THIS IS A PRIME EXAMPLE OF A HIGH
POPS/LOW QPF SCENARIO WHERE HIGH CONFIDENCE IN PRECIPITATION OVER
MUCH OF THE FORECAST AREA BUT LITTLE TO NO MEASURABLE PRECIPITATION
EXPECTED. HAVE MENTION OF AREAS OF DRIZZLE THROUGH THE AFTERNOON AND
THEN PATCHY FOG PAST 21Z. CHANCE OF RAIN SEEMS REASONABLE GIVEN THE
DEPTH OF THE MOISTURE GRADUALLY INCREASING THIS AFTERNOON BUT
BELIEVE THE PREDOMINANT WEATHER WILL BE DRIZZLE THROUGH 00Z
THURSDAY. NO SIGNIFICANT CHANGES TO ONGOING MAX TEMPS TODAY WITH A
MINOR INCREASE OVER THE SOUTH PER DECENT WAA AND INCREASED MOISTURE.
.LONG TERM /TONIGHT THROUGH TUESDAY/...
ISSUED AT 332 AM CST WED NOV 25 2015
CONCERNS BECOMING MORE APPARENT FOR ACCUMULATING ICE OVER THE WEST
AND SOUTHWEST BY THURSDAY AFTERNOON AND THEN CONTINUING INTO THE
NIGHTTIME HOURS SOUTHEAST. MODELS CONTINUE IN GENERAL AGREEMENT
WITH COLD AIR SLIDER BENEATH THE TROUGH OVER THE WEST AND
NORTHWEST BY 36 HOURS. PRIOR TO THAT SIGNIFICANT UPGLIDE ACROSS
THE SFC BOUNDARY WITH STRONG MOISTURE TRANSPORT WILL RESULT IN
RATHER ROBUST RAINFALL AMOUNTS FOR LATE NOVEMBER ACROSS THE
CENTRAL AND SOUTHEAST WHERE UPWARDS OF 1.75 TO NEARLY 2 INCHES OF
RAINFALL IS EXPECTED. THE GFS EVEN BRINGS DIMINISHING ELEVATED
CAPE TO THE BORDER AND OVER SOUTHERN IOWA ON THURSDAY...BUT FOR
NOW WILL LEAVE OUT OF GRIDS. TONIGHT WILL FEATURE MOISTURE
TRANSPORT INCREASING ALONG THE BOUNDARY WITH SOUNDINGS CONTINUING
TO SATURATE ALONG WITH TEMPERATURES REMAINING NEARLY STEADY IN THE
LOWER 30S NORTHWEST TO THE UPPER 40S IN THE SOUTHEAST FROM
MIDNIGHT THROUGH TOMORROW MORNING. AS RAINFALL INCREASES NORTHWEST
AND THE BOUNDARY BEGINS TO DRIFT SOUTHEAST AS THE WAVE
APPROACHES...BUFR SOUNDINGS OVER THE WEST SHOW THAT THE COLD AIR
NEAR THE SFC WILL BEGIN TO UNDERCUT THE WARMER AIR ALOFT CREATING
A PERIOD OF 2 TO 3 HOURS OF FREEZING RAIN BEGINNING OVER THE
NORTHWEST AROUND 12Z THEN PROGRESSING SOUTH SOUTHEAST DURING THE
DAY AND AFTERNOON HOURS AS THE COLDER AIRMASS CONTINUES TO
UNDERCUT THE BOUNDARY THROUGH THE AFTERNOON HOURS.
THERE ARE SEVERAL UNCERTAINTIES IN THE FORECAST FOR ICE
ACCUMULATION THAT NEED TO BE ADDRESSED/CONSIDERED. FIRST WE WILL
BE MILD OVER MUCH OF THE AREA TODAY AND A PORTION OF TONIGHT PRIOR
THE CHANGEOVER BEGINNING TOMORROW MORNING. SECOND...THE SATURATED
GROUND MAY RETAIN MORE HEAT AND COOL LESS QUICKLY ONCE THE COLDER
AIR ADVANCES ACROSS THE AREA. THESE TWO FACTORS MAY REDUCE THE
TOTAL ICE ACCUMULATION ON GROUND SURFACES...BUT OBJECTS THAT COOL
QUICKLY WITH AIR TEMPERATURE CHANGES WILL MORE LIKELY ACCUMULATE
ICE AT A MORE NORMAL RATE. THUS...THE IMPACTS MAY BE MORE RELATED
TO ICE ACCUMULATION ON METAL OBJECTS...COLDER SURFACES AND
EVENTUALLY ROADS AS TEMPERATURES CONTINUE TO COOL THROUGH THE
EVENING HOURS. GIVEN THE TIMING OF THE CHANGEOVER...THE
NORTHWEST/WEST AREAS LOOK TO IN LINE TO RECEIVE MORE FREEZING RAIN
THEN AREAS IN THE CENTRAL AND SOUTHEAST. HOWEVER THAT BEING
SAID...THE CHANGEOVER WILL AFFECT MOST OF THE FORECAST AREA WITH
SOME FREEZING RAIN. CURRENTLY HAVE OUTLINED THE AREAS THAT HAVE
THE POTENTIAL TO REACH NEAR .20 ICE ACCUMULATIONS OR SLIGHTLY
HIGHER WITH A WATCH. ELSEWHERE THERE WILL STILL BE A DECENT CHANCE
AT SOME FREEZING RAIN POTENTIAL ACROSS NORTH CENTRAL THROUGH WEST
CENTRAL AREAS UP THROUGH 00Z AND THEN ACROSS THE SOUTHWEST THROUGH
NORTHEAST FROM 00 THROUGH 06Z FROM NEAR CRESTON NORTHEAST TO ABOUT
DES MOINES/AMES TO NEAR WATERLOO. THESE AREAS MAY RECEIVE UP TO A
TENTH OF AN INCH OF ICE ACCUMULATION. WILL LET THE DAY SHIFT
EVALUATE BUT LIKELY OTHER AREAS WILL NEED AN ADVISORY. AFTER 06Z
THE MOISTURE TRANSPORT BEGINS TO WEAKEN WITH ICE INTRODUCTION
ALOFT BECOMING LESS PREVALENT. THIS WILL RESULT IN LESSER ICE
ACCUMULATION...IF ANY IN THE SOUTHEAST. SNOWFALL AMOUNTS HAVE BEEN
CUT BACK WITH UP TO AN INCH IN THE NORTHWEST TO ABOUT A HALF INCH
THROUGH CENTRAL AREAS.
HIGHS THURSDAY WILL BE REACHED EARLY IN THE DAY WITH FALLING
TEMPERATURES FOR THE AFTERNOON AND EVENING HOURS. HIGH
TEMPERATURES FOLLOWING THE STORM WILL SETTLE INTO THE 30S FOR
FRIDAY AND SATURDAY. THE MODELS ARE ALREADY ADVERTISING THE CLOSED
LOW OVER THE WEST TO OPEN UP AND TRACK ACROSS THE CENTRAL
PLAINS/GREAT LAKES BY LATER ON SUNDAY INTO MONDAY. THE EURO IS A
BIT SLOWER BUT OVERALL THERE SHOULD BE A MIX OF RASN WITH THIS
EVENT. STILL A FAIR AMOUNT OF UNCERTAINTY WITH THE STORM AS IT
TRACKS EAST/NORTHEAST ACROSS THE REGION. BEYOND TUESDAY THE
PATTERN IS FORECAST TO RELAX AS A RIDGE BEGINS TO BUILD ACROSS THE
WEST.
&&
.AVIATION...25/12Z
ISSUED AT 540 AM CST WED NOV 25 2015
EXPECTING MVFR CIGS MOVE INTO THE TAF AREA LATE THIS MORNING AND
IFR/LIFR VIS/CIGS LATER THIS AFTERNOON INTO EARLY EVENING WITH
DRIZZLE DEVELOPING OVER MUCH OF CENTRAL IOWA. LOW CIGS CONTINUE
INTO THURSDAY MORNING WITH SOME IMPROVEMENT IN VIS AS PRECIP
CHANGES OVER TO MORE RAIN THAN DRIZZLE THIS EVENING. HRRR KEEPS
LIFR/IFR CIGS AT DSM/OTM/ALO THROUGH AT LEAST 08Z THURSDAY AND
HENCE HIGH CONFIDENCE WITH LOWER CIGS PERSISTING LATE IN THE
PERIOD.
&&
.HYDROLOGY...
ISSUED AT 326 AM CST WED NOV 25 2015
STILL SOME POTENTIAL FOR MINOR RIVER FLOODING SOUTHEAST A FEW DAYS
FOLLOWING THE RAINFALL...GIVEN THE PREVIOUS SNOWMELT NORTH AND THE
COMBINATION OF ADDITIONAL RAINFALL TONIGHT/THURSDAY.
&&
.DMX WATCHES/WARNINGS/ADVISORIES...
WINTER STORM WATCH FROM THURSDAY MORNING THROUGH LATE THURSDAY
NIGHT FOR ADAIR-ADAMS-AUDUBON-CALHOUN-CARROLL-CASS-CRAWFORD-
GREENE-GUTHRIE-POCAHONTAS-SAC-UNION.
&&
$$
SHORT TERM...PODRAZIK
LONG TERM...REV
AVIATION...PODRAZIK
HYDROLOGY...REV
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
559 AM CST WED NOV 25 2015
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 338 AM CST WED NOV 25 2015
SOME SIGNIFICANT CHANGES WERE MADE TO THE FORECAST FOR TODAY AND
TONIGHT...WITH IT NOT LOOKING TO BE AS WET /ESPECIALLY TONIGHT/ OR
AS FOGGY AS WE WERE ADVERTISING. IN ADDITION...FROM THE AVIATION END
OF THINGS...CLOUD HEIGHTS LOOK TO BE QUITE A BIT HIGHER THAN
ORIGINALLY ANTICIPATED AS WELL.
TEMPERATURES OVERNIGHT HAVE REMAINED FAIRLY STEADY WITH A PERSISTENT
SE WIND BLOWING AND A HEALTHY AMOUNT OF CIRRUS OVERHEAD. AN INVERTED
THROUGH AT 3AM EXTENDED FROM A LEE SIDE LOW OVER CO NORTHEAST TO THE
NW CORNER OF MN. THOUGH THERE IS EXTENSIVE STRATUS IN THE MOIST
SOUTHERLY FLOW AHEAD OF THE LOW/TROUGH...THIS STRATUS HAS BEEN
FAIRLY HIGH BASED...WITH ALL OF IOWA STILL AT OR ABOVE 4K FT...EVEN
AT 3AM. THIS IS PROBABLY THE BIGGEST REASON FOR STARTING TO BACK
AWAY FROM THE HIGH POPS AND PROLONGED DRIZZLE MENTION WE HAD. TO GET
DZ...YOU WANT TO SEE CLOUDS UNDER AT LEAST 1K FT...500 FT IS EVEN
BETTER...BUT LOWEST STRATUS DOWN IN KS IS ONLY DOWN AROUND 2K FT. 1
KM REFLECTIVITY FROM SEVERAL OF THE CAMS HAS SPORADIC RETURNS AHEAD
OF THE FRONT TODAY...THOUGH THAT IS MORE OF A REFLECTION OF
SATURATION AT THIS LEVEL AS OPPOSED TO PRECIP GENERATION...AS
EVIDENCED BY THE LACK OF RETURNS WITH THE INSTANTANEOUS PRECIP RATE
FIELD FROM THE HOPWRF. REALLY...IT DOES NOT LOOK LIKE THE DEEPER
MOISTURE AND FORCING FINALLY HOOKUP UNTIL THE MOISTURE PLUME AT H85
IS OFF TO THE EAST OF THE MPX AREA. THIS IDEA IS HIGHLIGHTED WELL BY
PRETTY MUCH ALL MEMBERS OF THE NCAR ENSEMBLE WRF...WHICH SHOW
SCATTERED SHOWERS DEVELOPING LATE THIS AFTERNOON EAST OF THE MPX
AREA. FOR TONIGHT...WITH THE FRONTAL BOUNDARY WORKING EAST OF THE
AREA...THAT WILL FURTHER HELP SUPPRESS OUR PRECIP POTENTIAL...WITH
THE MAIN PRECIP SHIELD WITH OUR POTENTIAL THANKSGIVING DAY WINTRY
PRECIP NOT ARRIVING UNTIL AFTER 12Z THURSDAY.
FOR TEMPERATURES...WITH NOT AS MUCH LOW STRATUS EXPECTED TODAY...
COMBINED WITH A HIGH STARTING POINT THIS MORNING AND THE OVER
ACHIEVING TEMPERATURES THE PAST COUPLE OF DAYS...DID BOOST HIGHS
INTO THE MID/UPPER 40S FOR EAST OF THE BOUNDARY THIS AFTERNOON.
TONIGHT...WE SHOULD SEE A PRETTY GOOD GRADIENT IN LOWS...WITH STRONG
CAA SENDING LOWS DOWN CLOSE TO 20 IN WRN MN...WITH THE LATER ARRIVAL
OF THE COLD AIR AND CONTINUED CLOUD COVER KEEPING THE EAST END OF
THE MPX AREA UP ABOVE FREEZING ONCE AGAIN.
.LONG TERM...(THURSDAY THROUGH TUESDAY)
ISSUED AT 338 AM CST WED NOV 25 2015
THE THANKSGIVING SNOW EVENT REMAINS THE MAIN FORECAST CONCERN IN
THE LONG TERM. EVENTUALLY A CUT-OFF UPPER LOW WILL DRIFT NORTHEAST
AND GET CAUGHT UP IN THE WESTERLIES. THIS WILL BRING PRECIP TO THE
AREA EARLY NEXT WEEK...BUT WE CAN REFINE THE FORECASTS FOR THIS
EVENT FRI/SAT/SUN. THURSDAYS POTENTIAL TRAVEL IMPACTS REMAIN THE
FOCUS THIS MORNING.
WE WONT HAVE ANY WINTER WEATHER HEADLINES LOCALLY THIS MORNING DUE
TO UNCERTAINTY AND ALSO BASED ON THE FACT THAT OUR SNOW FORECAST
IS IN THE 1-3 INCH RANGE ACROSS THE EASTERN FORECAST AREA.
TODAY...HOWEVER...WE ARE GOING TO HAVE AN INTERNAL CONFERENCE CALL
WITH SURROUNDING NWS OFFICES...SO THE DAY SHIFT WILL ASSESS THE
WEATHER SITUATION AND COLLABORATE ANY WINTER WEATHER HEADLINES IF
NEEDED.
THE 00Z-06Z GUIDANCE HASNT DEVIATED A WHOLE LOT FROM YESTERDAYS
MODEL OUTPUT. THE GFS/ECMWF HAVE SHIFTED THE QPF PATTERN ABOUT A
COUNTY FARTHER SOUTHEAST...AND WITH THE SLOWLY EVOLVING POSITIVE
TILT TO THE SYSTEM AND POTENTIAL FOR CONVECTIVE ELEMENTS SOUTH OF
THE FORECAST AREA...WE REALLY CANT ENVISION A DRAMATIC SHIFT TO
THE NORTH. THIS MEANS THE ENTIRE WESTERN HALF OF THE FORECAST AREA
/INCLUDING ST. CLOUD...REDWOOD FALLS AND EVEN THE NORTHWEST TC
METRO/ WILL LIKELY END UP WITH LITTLE SNOW OUT OF THIS SYSTEM. WE
THINK THE P-TYPE FOR MOST OF EAST CENTRAL AND SOUTH CENTRAL MN
WILL BE SNOW. THEREFORE...WE ARE FAIRLY CONFIDENT IN THE 1-3" OF
SNOW FORECASTED FOR AREAS LIKE MANKATO...THE TWIN CITIES
METRO...AND FAR WEST CENTRAL WI. THE BIGGER CONCERN REMAINS FOR
AREAS JUST TO THE EAST OF THIS LINE - THIS INCLUDES AREAS SUCH AS
ALBERT LEA...RED WING AND EAU CLAIRE. THE P-TYPE IS MORE IN
QUESTION IN THESE AREAS...BUT IF THERE IS A QUICKER CHANGE OVER TO
SNOW...THAN THE 1-3 INCHES IN THE FORECAST WONT BE ENOUGH AND
AMOUNTS COULD BE CLOSER TO 5 OR 6 INCHES. THE NAM PRODUCES SNOW
AMOUNTS OF 5-7 INCHES IN THE EASTERN FORECAST AREA...BUT IT IS
ALSO A STRONGER/WESTERN AND SLOWER OUTLIER COMPARED TO THE
GFS/ECMWF/GEM.
AS MENTIONED IN PREVIOUS DISCUSSIONS...THE MOISTURE AND
TEMPERATURE GRADIENT IN THE EASTERN FORECAST AREA IS
IMPRESSIVE...BUT THE FGEN ISNT IS AS GOOD AS YOU MIGHT THINK...DUE
TO WEAKER CONVERGENCE. HOWEVER...THESE AREAS IN THE FAR EASTERN
FORECAST AREA SHOULD END UP JUST WEST OF THE RAIN/SNOW LINE BY
00Z FRIDAY AND THAT`S USUALLY A GOOD SPOT TO BE FOR MELTING
INDUCED FRONTOGENESIS. SO...THERE COULD BE A 2-4 HOUR WINDOW LATE
THURSDAY AFTERNOON OR THURSDAY EVENING WITH A QUICK CHANGE OVER TO
SNOW AND MODERATE TO HEAVY SNOW BASED ON THE ENHANCED LIFT AND
SLIGHT SURFACE COOLING. NOW THE SURFACE TEMPS IN WESTERN WI AND
FAR EASTERN MINNESOTA WILL BE NEAR THE FREEZING MARK AND WHILE THE
900MB-850MB TEMPS ARE COLD...THE WHOLE SOUNDING ISNT VERY COLD AND
THE DENDRITE GROWTH ZONE IS ACTUALLY HIGHER THAN THE BEST LIFT AND
FGEN...THIS ZONE IS ALSO FAIRLY NARROW. AS A RESULT...WE DONT
EXPECT HIGH SNOW RATIOS...PROBABLY MORE LIKE 8-10:1 IN WI AND FAR
EASTERN MN.
IN SUMMARY...THERE WILL BE SNOW IN EASTERN AND SOUTHERN MN...AND
WE DONT EXPECT MAJOR IMPACTS GIVEN OUR CONFIDENCE IN THE 1-3"
TOTALS. HOWEVER...BIGGER POTENTIAL IMPACTS ARE POSSIBLE IN THE
ALBERT LEA...RED WING AND EAU CLAIRE AREAS WHERE A QUICKER CHANGE
OVER TO SNOW COULD LEAD TO AMOUNTS THAT APPROACH 6 INCHES...OR A
HEALTHY COMBINATION OF SLEET AND SNOW.
THE WEEKEND LOOKS DRY WITH NEAR NORMAL TEMPS.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z THURSDAY MORNING)
ISSUED AT 555 AM CST WED NOV 25 2015
DESPITE MOIST SE FLOW THROUGH THE NIGHT...CIGS HAVE BEEN SLOW TO
DESCEND...THOUGH WE ARE STARTING TO SEE SOME MVFR CIGS COME OUT
OF NW IOWA THAT WILL SPREAD N/NE THIS MORNING. FAVORED THE HRRR
FOR BRINGING LOWER CIGS INTO TAFS..THOUGH DID NOT GO QUITE AS LOW
AS WHAT THE HRRR HAS...PREFERING TO KEEP CIGS TODAY MAINLY MVFR
BASED ON THE LACK OF IFR CIGS TO THE SOUTH. BESIDE THESE CLOUDS TO
THE SOUTH...AS THE FRONT APPROACHING WRN MN MOVES THROUGH...WE
WILL SEE IFR/MVFR CIGS DROP SOUTH OUT OF NODAK...THOUGH THOSE ARE
DESTINED TO IMPACT MPX TERMINALS THIS AFTERNOON INTO TONIGHT. FOR
PRECIP...AGAIN FOLLOWED THE IDEA OF THE HRRR WITH A FEW SHOWERS
DEVELOPING AHEAD OF THE FRONT THIS AFTERNOON FOR ERN MN AND WRN
WI...THOUGH NOT EXPECTING MUCH OUT OF THIS.
KMSP...WE WILL SEE CIGS SLOWLY LOWER THROUGH THE DAY AS THE COLD
FRONT MOVES IN FROM THE WEST. TIMING FOR THE FROPA STILL LOOKS
GOOD AROUND 23Z WITH WINDS GRADUALLY VEERING FROM THE SOUTH OVER
TO THE NW BETWEEN 18Z AND 3Z. MAY SEE CIGS DROP BELOW 018 BRIEFLY
WITH THE FROPA...BUT NOT ANTICIPATING CIGS BELOW THAT LEVEL FOR
GOOD UNTIL WE GET BEHIND THE FRONT. FOR THE END OF THE TAF
PERIOD...SNOW WILL BE APPROACHING MSP FROM THE SOUTH. STILL A FAIR
AMOUNT OF SPREAD WITH HOW QUICKLY SNOW GETS HERE...WITH THE GFS
GOING SHORTLY AFTER 12Z THU AND THE NAM NOT UNTIL AFTER 18Z. FOR
NOW...WENT WITH SOMETHING IN BETWEEN AND THIS CAN BE REFINED
THROUGH THE DAY TODAY.
/OUTLOOK FOR KMSP/
THU...IFR WITH SN. WINDS N 10-20 KTS.
FRI...VFR. WINDS NNW 5-10 KTS.
SAT...VFR. WINDS SW 5 KTS.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
&&
$$
SHORT TERM...MPG
LONG TERM...CLF
AVIATION...MPG
AREA FORECAST DISCUSSION...UPDATED
NWS JACKSON MS
949 AM CST WED NOV 25 2015
.UPDATE...VERY PLEASANT CONDITIONS OCCURRING THIS THANKSGIVING EVE AS
TEMPERATURES ARE RUNNING ABOUT 10 DEGREES WARMER THAN 24 HOURS AGO.
THIS IS THANKS IN PART TO THE SOUTHERLY FLOW THAT HAS RETURNED TO
THE REGION AS A RESULT OF BEING ON THE WESTERN PERIPHERY OF A SFC
HIGH CENTERED OVER THE COAST OF MAINE. SOME CLOUD COVER WILL
INCREASE TODAY BUT SUNNY SKIES WILL MOSTLY PREVAIL AND HELP
TEMPERATURES INCREASE INTO THE UPPER 60S/LOWER 70S AS AN UPPER RIDGE
BUILDS ACROSS THE REGION. GOING FORECAST IS IN DECENT SHAPE AND MADE
A FEW ADJUSTMENTS TO INCREASE HIGH TEMPERATURES IN A COUPLE OF
LOCATIONS THAT ARE ALREADY WARMING QUICKLY. ALSO MADE SOME
ADJUSTMENTS TO HOURLY TEMPS AND SKY COVER. OVERALL...IT SHOULD BE A
RATHER FABULOUS TRAVEL DAY FOR MANY ACROSS THE ARKLAMISS AND MOST OF
THE SOUTHEAST UNITED STATES. /28/
&&
.PREV DISCUSSION... /ISSUED 420 AM CST WED NOV 25 2015/
DISCUSSION...
TODAY THROUGH THURSDAY NIGHT...
A DEEP LONGWAVE TROUGH OVER THE WESTERN CONUS WILL INDUCE AN
ANOMALOUS DOWNSTREAM RIDGE OVER THE CENTRAL GULF COAST REGION AS WE
MOVE INTO LATTER PORTIONS OF THE WEEK. STRONG MID LEVEL SUBSIDENCE
WILL GREATLY LIMIT RAIN CHANCES...BUT LOW LEVEL MOISTURE TRANSPORT
COULD BE SUFFICIENT TO PRODUCE ISOLATED SHOWER ACTIVITY OVER NE LA/SW
MS THIS AFTN PER RECENT HRRR AND OTHER HIGH RES NEAR TERM GUIDANCE.
THIS PATTERN WILL BRING MUCH MILDER LOW TEMPERATURES TO THE
ARKLAMISS WITH READINGS EXPECTED TO BE ~ 15 DEG F ABOVE CLIMATE
NORMALS. HIGH TEMPERATURES WILL BE WARMER THAN RECENTLY
OBSERVED...BUT THE WARMTH SHOULD BE TEMPERED SOME BY INCREASING
STRATOCUMULUS COVERAGE AND ESE FLOW EMANATING FROM A SLIGHTLY COOLER
AIRMASS WEDGING AROUND THE SOUTHERN APPALACHIANS. STILL EXPECT HIGHS
TO BE 5 TO 10 DEG ABOVE CLIMATOLOGY ON AVERAGE...BUT A FEW COOLER
POCKETS WILL BE POSSIBLE WHERE CLOUD COVER IS MORE PERSISTENT...
ESPECIALLY OVER EAST CENTRAL MS. /EC/
LONG TERM (FRIDAY THROUGH NEXT TUESDAY)...THE PRIMARY CONCERN IN THE
EXTENDED IS PRECIP TIMING FOR LATE THIS WEEK INTO NEXT WEEK.
AT THE BEGINNING OF THE PERIOD, AN UPPER TROUGH EXTENDING FROM
HUDSON BAY INTO THE NORTHERN PLAINS WILL BE IN THE PROCESS OF
CUTTING OFF AN UPPER LOW OVER CALIFORNIA/NEVADA. A SLOW MOVING COLD
FRONT WILL BE POSITIONED FROM THE GREAT LAKES THROUGH THE MID
MISSISSIPPI VALLEY TO THE RED RIVER VALLEY, WITH CONSIDERABLE RAIN
ONGOING IN THOSE AREAS.
HEADING INTO THE WEEKEND, CONSIDERABLE TIMING/PATTERN INCONGRUITIES
REMAIN AMONG OP/ENSEMBLE MODEL GUIDANCE, THUS DID NOT STRAY FAR FROM
ENSEMBLE MEAN AND MODEL BLEND POPS. AT THIS TIME IT APPEARS
ELONGATED MID LEVEL RIDGING AND (AT LEAST IN THE EASTERN HALF OF THE
AREA) WEDGING SURFACE HIGH PRESSURE WILL HELP DEFLECT PRECIP LARGELY
TO THE NORTHWEST THROUGH FRIDAY - MEANING DRY CONDITIONS FOR POST-
THANKSGIVING BARGAIN HUNTERS. SUBTLE IMPULSES EMBEDDED WITHIN AN
UPPER LEVEL SOUTHWESTERLY FLOW REGIME WILL ULTIMATELY ACT TO LOWER
HEIGHTS INTO THE WEEKEND. AS A RESULT, RAIN CHANCES WILL BEGIN TO
CLIMB, ESPECIALLY IN THE NORTHWEST BY SATURDAY WITH MORE WIDESPREAD
COVERAGE POSSIBLE SUNDAY AS A STRONGER DISTURBANCE IS EXPECTED TO
MOVE THROUGH.
THROUGH THE WEEKEND INTO EARLY NEXT WEEK, THE CUTOFF UPPER LOW WILL
MIGRATE INTO THE UPPER PLAINS. AS THE UPPER JET REMAINS NORTH OF THE
REGION ALMOST PARALLEL TO THE SURFACE FRONT, THE FRONT WILL ONLY
MEANDER INTO THE AREA THROUGH EARLY NEXT WEEK, GRADUALLY WEAKENING
WITH THE LOSS OF UPPER SUPPORT. HOWEVER, ABOVE AVERAGE PW IN THE 1
TO 1.5 INCH RANGE WILL STILL EXIST ACROSS THE AREA, KEEPING THE
POSSIBILITY FOR SCATTERED SHOWERS AROUND INTO EARLY NEXT WEEK.
THROUGHOUT THE ENTIRE PERIOD, ONLY ISOLATED TO LOWER END CHANCE POPS
WILL BE INCLUDED ACROSS THE PINE BELT AS THE FRONT LOOKS TO REMAIN
FARTHEST AWAY FROM THIS AREA. GUIDANCE CONTINUES TO SHOW LITTLE TO
NO INSTABILITY WITH THIS SYSTEM, THUS WE WILL CONTINUE TO KEEP
THUNDER OUT OF THE FORECAST. /DL/
AVIATION...INCREASING MOISTURE TRANSPORT IS BRINGING AN END TO A
LONG STREAK OF MOSTLY CLEAR SKIES WITH 4000-5000 FT CIGS ALREADY
DEVELOPING OVER THE HBG-MEI CORRIDOR EARLY THIS MORNING...BUT STILL
EXPECT MAINLY VFR CATEGORY CIGS AS WE GO THROUGH TODAY INTO THIS
EVENING. THIS SHOULD CHANGE EARLY THURSDAY MORNING WHEN THE POTENTIAL
FOR 1000-1500 FT CIGS INCREASES DURING THE PRE-DAWN HOURS.
&&
.PRELIMINARY POINT TEMPS/POPS...
JACKSON 70 54 70 57 / 0 2 5 4
MERIDIAN 67 48 70 52 / 0 1 3 4
VICKSBURG 69 55 74 59 / 0 4 6 7
HATTIESBURG 71 53 72 55 / 0 4 7 4
NATCHEZ 69 57 73 60 / 0 4 6 7
GREENVILLE 67 54 70 59 / 0 3 9 9
GREENWOOD 68 52 70 57 / 0 2 10 4
&&
.JAN WATCHES/WARNINGS/ADVISORIES...
MS...NONE.
LA...NONE.
AR...NONE.
&&
$$
28/CME/EC/DL
AREA FORECAST DISCUSSION
NWS JACKSON MS
420 AM CST WED NOV 25 2015
.DISCUSSION...
TODAY THROUGH THURSDAY NIGHT...
A DEEP LONGWAVE TROUGH OVER THE WESTERN CONUS WILL INDUCE AN
ANOMALOUS DOWNSTREAM RIDGE OVER THE CENTRAL GULF COAST REGION AS WE
MOVE INTO LATTER PORTIONS OF THE WEEK. STRONG MID LEVEL SUBSIDENCE
WILL GREATLY LIMIT RAIN CHANCES...BUT LOW LEVEL MOISTURE TRANSPORT
COULD BE SUFFICIENT TO PRODUCE ISOLATED SHOWER ACTIVITY OVER NE LA/SW
MS THIS AFTN PER RECENT HRRR AND OTHER HIGH RES NEAR TERM GUIDANCE.
THIS PATTERN WILL BRING MUCH MILDER LOW TEMPERATURES TO THE
ARKLAMISS WITH READINGS EXPECTED TO BE ~ 15 DEG F ABOVE CLIMATE
NORMALS. HIGH TEMPERATURES WILL BE WARMER THAN RECENTLY
OBSERVED...BUT THE WARMTH SHOULD BE TEMPERED SOME BY INCREASING
STRATOCUMULUS COVERAGE AND ESE FLOW EMANATING FROM A SLIGHTLY COOLER
AIRMASS WEDGING AROUND THE SOUTHERN APPALACHIANS. STILL EXPECT HIGHS
TO BE 5 TO 10 DEG ABOVE CLIMATOLOGY ON AVERAGE...BUT A FEW COOLER
POCKETS WILL BE POSSIBLE WHERE CLOUD COVER IS MORE PERSISTENT...
ESPECIALLY OVER EAST CENTRAL MS. /EC/
LONG TERM (FRIDAY THROUGH NEXT TUESDAY)...THE PRIMARY CONCERN IN THE
EXTENDED IS PRECIP TIMING FOR LATE THIS WEEK INTO NEXT WEEK.
AT THE BEGINNING OF THE PERIOD, AN UPPER TROUGH EXTENDING FROM
HUDSON BAY INTO THE NORTHERN PLAINS WILL BE IN THE PROCESS OF
CUTTING OFF AN UPPER LOW OVER CALIFORNIA/NEVADA. A SLOW MOVING COLD
FRONT WILL BE POSITIONED FROM THE GREAT LAKES THROUGH THE MID
MISSISSIPPI VALLEY TO THE RED RIVER VALLEY, WITH CONSIDERABLE RAIN
ONGOING IN THOSE AREAS.
HEADING INTO THE WEEKEND, CONSIDERABLE TIMING/PATTERN INCONGRUITIES
REMAIN AMONG OP/ENSEMBLE MODEL GUIDANCE, THUS DID NOT STRAY FAR FROM
ENSEMBLE MEAN AND MODEL BLEND POPS. AT THIS TIME IT APPEARS
ELONGATED MID LEVEL RIDGING AND (AT LEAST IN THE EASTERN HALF OF THE
AREA) WEDGING SURFACE HIGH PRESSURE WILL HELP DEFLECT PRECIP LARGELY
TO THE NORTHWEST THROUGH FRIDAY - MEANING DRY CONDITIONS FOR POST-
THANKSGIVING BARGAIN HUNTERS. SUBTLE IMPULSES EMBEDDED WITHIN AN
UPPER LEVEL SOUTHWESTERLY FLOW REGIME WILL ULTIMATELY ACT TO LOWER
HEIGHTS INTO THE WEEKEND. AS A RESULT, RAIN CHANCES WILL BEGIN TO
CLIMB, ESPECIALLY IN THE NORTHWEST BY SATURDAY WITH MORE WIDESPREAD
COVERAGE POSSIBLE SUNDAY AS A STRONGER DISTURBANCE IS EXPECTED TO
MOVE THROUGH.
THROUGH THE WEEKEND INTO EARLY NEXT WEEK, THE CUTOFF UPPER LOW WILL
MIGRATE INTO THE UPPER PLAINS. AS THE UPPER JET REMAINS NORTH OF THE
REGION ALMOST PARALLEL TO THE SURFACE FRONT, THE FRONT WILL ONLY
MEANDER INTO THE AREA THROUGH EARLY NEXT WEEK, GRADUALLY WEAKENING
WITH THE LOSS OF UPPER SUPPORT. HOWEVER, ABOVE AVERAGE PW IN THE 1
TO 1.5 INCH RANGE WILL STILL EXIST ACROSS THE AREA, KEEPING THE
POSSIBILITY FOR SCATTERED SHOWERS AROUND INTO EARLY NEXT WEEK.
THROUGHOUT THE ENTIRE PERIOD, ONLY ISOLATED TO LOWER END CHANCE POPS
WILL BE INCLUDED ACROSS THE PINE BELT AS THE FRONT LOOKS TO REMAIN
FARTHEST AWAY FROM THIS AREA. GUIDANCE CONTINUES TO SHOW LITTLE TO
NO INSTABILITY WITH THIS SYSTEM, THUS WE WILL CONTINUE TO KEEP
THUNDER OUT OF THE FORECAST. /DL/
&&
.AVIATION...INCREASING MOISTURE TRANSPORT IS BRINGING AN END TO A
LONG STREAK OF MOSTLY CLEAR SKIES WITH 4000-5000 FT CIGS ALREADY
DEVELOPING OVER THE HBG-MEI CORRIDOR EARLY THIS MORNING...BUT STILL
EXPECT MAINLY VFR CATEGORY CIGS AS WE GO THROUGH TODAY INTO THIS
EVENING. THIS SHOULD CHANGE EARLY THURSDAY MORNING WHEN THE POTENTIAL
FOR 1000-1500 FT CIGS INCREASES DURING THE PRE-DAWN HOURS.
&&
.PRELIMINARY POINT TEMPS/POPS...
JACKSON 67 54 70 57 / 7 2 5 4
MERIDIAN 66 48 70 52 / 1 1 3 4
VICKSBURG 69 55 74 59 / 8 4 6 7
HATTIESBURG 71 53 72 55 / 3 4 7 4
NATCHEZ 69 57 73 60 / 12 4 6 7
GREENVILLE 66 54 70 59 / 5 3 9 9
GREENWOOD 65 52 70 57 / 6 2 10 4
&&
.JAN WATCHES/WARNINGS/ADVISORIES...
MS...NONE.
LA...NONE.
AR...NONE.
&&
$$
/EC/DL/
AREA FORECAST DISCUSSION
NWS NORTH PLATTE NE
550 AM CST WED NOV 25 2015
.SYNOPSIS...
ISSUED AT 340 AM CST WED NOV 25 2015
A CONVOLUTED H5 PATTERN CONTINUES TONIGHT ACROSS NOAM WITH A
RIDGE EXTENDING FROM THE NE PACIFIC INTO THE GULF OF ALASKA.
DOWNSTREAM OF THE RIDGE...A TROUGH EXTENDED FROM NRN SASKATCHEWAN
INTO NRN CALIFORNIA. AT THE BASE OF THIS TROUGH...CLOSED LOW
PRESSURE WAS NOTED OVER SWRN OREGON. EAST OF THE TROUGH...A ZONAL
PATTERN EXISTED ACROSS THE REMAINDER OF THE LOWER 48 STATES WITH
THE EXCEPTION OF A PERSISTENT TROUGH WHICH EXTENDED FROM EASTERN
QUEBEC...SWD INTO NEW ENGLAND. AT THE SURFACE...A FRONTAL
BOUNDARY WAS ANCHORED ALONG THE NEBR/SD BORDER AND MARKED THE
LEADING EDGE OF ARCTIC AIR WHICH WAS ENTRENCHED ACROSS THE NRN
PLAINS. READINGS OFF TO THE NORTH WERE IN THE TEENS IN MONTANA
WITH BREEZY NORTHERLY WINDS. SOUTH OF THE FRONT...TEMPERATURES
WERE IN THE 20S TO LOWER 30S WITH THE EXCEPTION SERN NEBRASKA
WHERE 40S AND LOWER 50S WERE COMMON THANKS TO LOW CLOUDS AND A
DECENT INFLUX OF LOW LEVEL MOISTURE PUSHING NORTH FROM EASTERN
KANSAS. FOR NOW...THE STRATUS AND LOW LEVEL MOISTURE HAS STAYED
JUST OFF TO THE EAST AND SOUTHEAST OF THE FORECAST AREA AND
SHOULD REMAIN THERE BASED ON THE LATEST HRRR FORECAST.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 340 AM CST WED NOV 25 2015
FOR TODAY AND TONIGHT...THE MAIN FORECAST CHALLENGE WILL BE THE
THREAT FOR A WINTRY MIX OF PCPN BEGINNING TONIGHT. FOR
TODAY...THE ARCTIC COLD FRONT WILL PUSH SOUTH THIS MORNING AND
WILL CLEAR MOST OF THE FORECAST AREA BY MID AFTERNOON. HIGHS
TODAY WILL STRUGGLE TO GET OUT OF THE 30S IN THE
NORTHWEST...WHILE 40S ELSEWHERE REMAIN ON TRACK FOR THE FORECAST.
LIKE YESTERDAY...THERE WAS A LARGE DISPARITY IN HIGH TEMPERATURES
BETWEEN THE MAV AND MET GUIDANCE. THE MET SEEMED TOO COOL FOR
NORTH PLATTE TODAY WITH ITS HIGH OF 38 GIVEN THE LATER FRONTAL
TIMING OF EARLY AFTERNOON AND TRENDED THE TEMP FORECAST MORE
TOWARD THE WARMER MAV GUIDANCE. HOWEVER DID NOT GO WITH HIGHS AS
WARM AS THE MAV GUIDANCE SUGGESTS. THIS WAS DUE TO AN ABUNDANCE
OF MID AND HIGH LEVEL CLOUD COVER EXPECTED TODAY IN ADVANCE OF
THE APPG COLD FRONT.
TONIGHT...LOW LEVEL MOISTURE WILL INCREASE BEHIND THE EXITING
COLD FRONT AS A SHIELD OF STRATUS DEVELOPS ACROSS WESTERN AND
NORTH CENTRAL NEBRASKA. ABOVE THE STRATUS...A DECENT DRY LAYER
WILL EXIST WITH SOME WEAK LIFT NOTED JUST ABOVE THE STRATUS LAYER
OVERNIGHT. A THOROUGH EXAMINATION OF BUFKIT FORECAST SOUNDINGS
INDICATES A DECENT SETUP FOR FREEZING DRIZZLE TONIGHT...ROUGHLY
EAST OF A LINE FROM SPRINGVIEW TO OGALLALA. WEST OF THIS
LINE...TEMPERATURE PROFILES IN THE MOIST LAYER SEEM TOO COLD FOR
THE DEVELOPMENT OF FREEZING DRIZZLE AND HAVE OPTED FOR A MENTION
OF SNOW AS THERE IS SOME INDICATION OF MID LEVEL
MOISTENING...ESPECIALLY OVER NORTHWESTERN PORTIONS OF THE CWA
OVERNIGHT. EVEN WITH THE MID LEVEL MOISTENING...THE BEST MOISTURE
IS NOT COLLOCATED WITH THE BEST DENDRITIC TEMPERATURES...SO ANY
SNOW WILL BE VERY LIGHT IN NATURE. ACROSS THE FAR SOUTHEASTERN
CWA...TEMPS WILL BE WARM TO SUPPORT DRIZZLE OR VERY LIGHT RAIN
EARLY THIS EVENING...FOLLOWED BY AREAS OF FREEZING DRIZZLE
OVERNIGHT. LOW LEVEL MOISTURE WILL BE MOST FAVORABLE FOR MORE
WIDESPREAD FREEZING DRIZZLE OVERNIGHT ACROSS FRONTIER AND FAR
SERN CUSTER COUNTY OVERNIGHT...AS IT FLOWS NORTH INTO NEBRASKA
FROM KANSAS. WITH THIS IN MIND...HAVE DECIDED TO PLACE FRONTIER
COUNTY IN A WINTER WEATHER ADVISORY AS QPF FORECASTS ARE
INDICATIVE OF UP TO A FEW HUNDREDTHS OF AN INCH OF FREEZING PCPN.
HOWEVER...ATTM...THE GREATEST THREAT FOR ACCUMULATING FREEZING
PCPN APPEARS TO BE WELL EAST OF THE FORECAST AREA MORE INTO
THURSDAY. WILL RUN THE ADVISORY FROM MIDNIGHT CST TONIGHT THROUGH
6 PM CST THURSDAY.
.LONG TERM...(THURSDAY THROUGH TUESDAY)
ISSUED AT 340 AM CST WED NOV 25 2015
THE THANKSGIVING HOLIDAY TRAVEL EXPECTED TO BE IMPACTED ACROSS
MUCH OF THE AREA. A UPPER LEVEL LOW CUTS OFF ACROSS SW CONUS WITH
A POSITIVELY TILTED TROUGH ACROSS THE NORTHERN PLAINS. AT THE SFC
A COLD FRONT WILL BE EAST OF THE CWA WITH ARCTIC HIGH PRESSURE
BUILDING ACROSS THE ROCKIES. THE MAIN CONCERN FOR THE DAY ON
THURSDAY WILL BE THE LOWER LEVEL TEMP PROFILE AND THE POCKET OF
MID LEVEL DRY AIR. THE LATEST MODELS HAVE TRENDED SLIGHTLY
FURTHER EAST WITH THE COLD AIR AND BUFKIT SOUNDINGS NOW
SUGGESTING BY 12Z THE LOWER PROFILE ALL BELOW ZERO C AND HAVE
FORECAST NOW ALL SNOW. LIFT IS MARGINAL AND WILL BATTLE A POCKET
OF DRY AIR...SO EXPECT SNOW TO BE LIGHT AND WILL HAVE TO MONITOR
THE LEVEL OF DRYNESS AS PRECIP COULD SEE A MIX OF FREEZING
DRIZZLE HOWEVER NOT MENTIONED AT THIS TIME. THROUGH THE DAY
ACCUMULATION WILL BE LIGHT...LESS THAN AN INCH. AS FOR
TEMPS...THE COLD AIR ADVECTION AND PERSISTENT CLOUDS WILL LIMIT
WARMING. GUIDANCE SUGGEST TEMPS REBOUND A FEW DEGREES...HOWEVER
WOULD NOT BE SURPRISED IF TEMPS HELD STEADY OR EVEN FELL DURING
THE AFTERNOON. STILL WELL BELOW NORMAL WITH HIGHS IN THE MID TO
UPPER 20S.
COLD HIGH PRESSURE BUILDS ACROSS THE NORTHERN CWA THURSDAY NIGHT
INTO FRIDAY. THIS WILL USHER IN SOME DRY AIR AND CONFINE ANY SNOW
ACTIVITY TO THE SOUTHERN CWA...WHICH MAY NEED TO BE PUSHED
FURTHER SOUTH PENDING STRENGTH OF THE HIGH. LOWS ON THE COLD
SIDE...SINGLE DIGITS AND TEENS...REBOUNDING ONLY TO THE
20S...MAYBE 30 FOR FRIDAY.
OVER THE WEEKEND THE LOW WILL LIFT NORTH ACROSS THE ROCKIES AS
THE SFC HIGH SHIFTS EAST. RECYCLED COLD AIR WILL WRAP AROUND THE
HIGH AND OVER THE AREA. ALSO GOING TO SEE THE DRY AIR GET PUSHED
EAST WITH A LITTLE BETTER MOISTURE AND A RETURN TO AT LEAST A
SLIGHT CHANCE FOR LIGHT SNOW. THE LATEST EC BROUGHT A DISTURBANCE
AHEAD OF THE UPPER LEVEL LOW AND PRODUCED A BRIEF PERIOD OF
MODERATE SNOW SATURDAY NIGHT. WILL KEEP POPS LOW FOR NOW AND MAKE
A NOTE TO WATCH CAREFULLY.
EARLY NEXT WEEK THE UPPER LOW WILL SLIDE EAST ACROSS THE NORTHERN
PLAINS. COLD AIR REMAINS IN PLACE...HOWEVER COULD SEE SOME MORE
SUN AND HIGHS REBOUNDING INTO THE 30S. A CHANCE FOR SNOW MONDAY
REMAINS IN THE FORECAST...HOWEVER AS THE UPPER LEVEL LOW PUSHES
EAST THE CHANCE FOR ANY PRECIP DIMINISHES THROUGH MID WEEK.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z THURSDAY MORNING)
ISSUED AT 550 AM CST WED NOV 25 2015
FOR THE KLBF TERMINAL...FOG IS CURRENTLY MOVING NORTH FROM KANSAS
INTO SOUTHERN AND CENTRAL NEBRASKA. THIS WILL CONTINUE TO BE
MONITORED AS IT IS EXPECTED TO JUST PASS TO THE EAST OF THE KLBF
TERMINAL. FOR TODAY...EXPECT MOSTLY CLOUDY SKIES WITH CIGS
FALLING TO AROUND 5000 FT AGL BY 00Z THURSDAY. CIGS WILL FALL
FURTHER TO AROUND 1500 FT AGL OVERNIGHT WITH AN INCREASED THREAT
FOR FZDZ AFTER 05Z FRIDAY. FOR THE KVTN TERMINAL...LOOK FOR CIGS
TO FALL TO AROUND 5000 FT AGL BY MID MORNING TODAY...FALLING TO
1500 TO 2500 FT AGL THIS AFTERNOON. ATTM...THE MAIN THREAT FOR
FZDZ WILL BE SOUTH OF THE TERMINAL AND WILL NOT BE INCLUDED IN THE
12Z TAF ISSUANCE.
&&
.LBF WATCHES/WARNINGS/ADVISORIES... WINTER WEATHER ADVISORY FROM
MIDNIGHT TONIGHT TO 6 PM CST THURSDAY FOR NEZ071.
&&
$$
SYNOPSIS...BUTTLER
SHORT TERM...BUTTLER
LONG TERM...MASEK
AVIATION...BUTTLER
FOR FREQUENTLY ASKED QUESTIONS ABOUT THE AREA FORECAST DISCUSSION
VISIT...
HTTP://WEATHER.GOV/SALTLAKECITY/GENERAL/AFD_FAQS.PHP (ALL LOWER CASE)
AREA FORECAST DISCUSSION
National Weather Service Lincoln IL
1103 AM CST WED NOV 25 2015
.UPDATE...
ISSUED AT 1058 AM CST WED NOV 25 2015
High pressure sliding off to the east while the next storm system
spins up over the southern Plains. A quick wave moving up through
the Upper Midwest bringing some light sprinkles with some of the
clouds this morning. Not measurable, but possibly enough to wet
pavement. Cloud bases relatively high this morning, but steadily
moving into the area. Not a lot of changes for the forecast
overall, but a mention of sprinkles moving up the I-55 corridor
for the rest of today ahead of the approaching showers later
tonight.
&&
.SHORT TERM...(Today)
ISSUED AT 330 AM CST WED NOV 25 2015
The CWA is in between the high pressure to the east and the
developing weather system in the plains. In this position, breezy
southerly winds and warmer temperatures are to be expected today.
With the increasing waa ahead of the developing system, an increase
in low level moisture is occurring, which is will bring an increase
in cloud cover to the area. The increasing clouds could retard the
warming trend this afternoon, but believe the strong waa should be
able to compensate. So, am expecting skies to become mostly cloudy
today with highs in the 50s and southerly winds of 15 to 25 mph.
.LONG TERM...(Tonight through Tuesday)
ISSUED AT 330 AM CST WED NOV 25 2015
00Z models are similar with cold front moving east into the IL river
valley Thu night and across eastern IL Friday afternoon. Aloft,
strong 538 dm 500 mb low over northern CA into nw NV will move
across the central Rockies on Thu and remain near the Rockies this
weekend and eject ne into the Midwest and Great Lakes on Monday
night and Tue. This will likely bring an extended unsettled weather
pattern to IL with daily rain chances through early next week.
Chances of light rain showers moves into the IL river valley this
evening and deeper into central IL overnight while southeast IL
remains dry. Milder lows tonight in the upper 40s to around 50F with
clouds and breezy south winds. Clouds and breezy south winds
continue Thu with highs in the upper 50s and lower 60s. Rain chances
also increase to 60-80% nw of the IL river by Thu afternoon and 40-
50% over heart of central IL while only 20-30% in southeast IL and
near the IN border. Rainfall amounts even nw of the IL river appear
fairly light on Thu with highest amounts near a quarter inch by
Galesburg.
Increased lift with approaching cold front and deeper moisture to
bring highest rain chances Thu night into Friday along with heaviest
rainfall ranging from 1-1.5 inches with rain chances likely
lingering over southeast IL Friday night where storm total rainfall
of 1.50-1.75 inches. This may cause some rivers and streams to go
back to near flood especially at Clay City on the Little Wabash
river. Flash flood guidance is 1.5-2 inches per hour and 2-3 inches
in 6 hours so these rainfall amounts are still less than that and
will hold off on a flood watch.
Surface low pressure to lift ne along frontal boundary just
southeast of the Ohio river into nw KY by Sunday morning. This will
likely lift showers back ne into central IL during this weekend
especially Sat night into Sunday morning. Highest rain chances will
be over southeast IL along with heaviest rainfall amounts. Even
though temps cool by this weekend, they still appear warm enough to
support rain over our area. Lingered 20-30% chances of light rain
showers early next work week as upper level low moves into the area
and keeps it cloudier and cooler.
&&
.AVIATION...(For the 12Z TAFS through 12Z Thursday morning)
ISSUED AT 524 AM CST WED NOV 25 2015
Clear skies will give way to clouds around 5kft moving into the
area this morning. The clouds will begin in the west at SPI and
PIA, then spread east and reach CMI last. Based on satellite
trends and upstream observations, looks like heights will remain
VFR levels, around 3.5kft. The clouds will continue through the
day and into the night ahead of the next weather system. HRRR and
NAM12 bring some light/scattered pcpn into the area beginning
late this afternoon and into tonight. Given the waa and all the
clouds, though not that low, will go with VCSH at all TAF sites in
the new forecast for late this afternoon and into this evening.
Winds will be southerly through the period with daytime gusts to
around 25kts. Winds will decrease some during the evening, but
expecting gusts to continue.
&&
.ILX Watches/Warnings/Advisories...
NONE.
&&
$$
UPDATE...HJS
SHORT TERM...Auten
LONG TERM...07
AVIATION...Auten
AREA FORECAST DISCUSSION...UPDATED
NWS JACKSON MS
1144 AM CST WED NOV 25 2015
.UPDATE...ADDED AVIATION DISCUSSION.
&&
.AVIATION...EXPECT MAINLY VFR CATEGORY CIGS FOR THIS AFTERNOON
THROUGH THE EVENING HOURS. THIS SHOULD CHANGE TO MVFR WHEN THE
POTENTIAL FOR 1000-1500 FT CIGS INCREASES LATER TONIGHT INTO THE PRE-
DAWN HOURS THURSDAY. /27/
&&
.PREV DISCUSSION... /ISSUED 949 AM CST WED NOV 25 2015/
UPDATE...VERY PLEASANT CONDITIONS OCCURRING THIS THANKSGIVING EVE AS
TEMPERATURES ARE RUNNING ABOUT 10 DEGREES WARMER THAN 24 HOURS AGO.
THIS IS THANKS IN PART TO THE SOUTHERLY FLOW THAT HAS RETURNED TO
THE REGION AS A RESULT OF BEING ON THE WESTERN PERIPHERY OF A SFC
HIGH CENTERED OVER THE COAST OF MAINE. SOME CLOUD COVER WILL
INCREASE TODAY BUT SUNNY SKIES WILL MOSTLY PREVAIL AND HELP
TEMPERATURES INCREASE INTO THE UPPER 60S/LOWER 70S AS AN UPPER RIDGE
BUILDS ACROSS THE REGION. GOING FORECAST IS IN DECENT SHAPE AND MADE
A FEW ADJUSTMENTS TO INCREASE HIGH TEMPERATURES IN A COUPLE OF
LOCATIONS THAT ARE ALREADY WARMING QUICKLY. ALSO MADE SOME
ADJUSTMENTS TO HOURLY TEMPS AND SKY COVER. OVERALL...IT SHOULD BE A
RATHER FABULOUS TRAVEL DAY FOR MANY ACROSS THE ARKLAMISS AND MOST OF
THE SOUTHEAST UNITED STATES. /28/
PREV DISCUSSION... /ISSUED 420 AM CST WED NOV 25 2015/
DISCUSSION...
TODAY THROUGH THURSDAY NIGHT...
A DEEP LONGWAVE TROUGH OVER THE WESTERN CONUS WILL INDUCE AN
ANOMALOUS DOWNSTREAM RIDGE OVER THE CENTRAL GULF COAST REGION AS WE
MOVE INTO LATTER PORTIONS OF THE WEEK. STRONG MID LEVEL SUBSIDENCE
WILL GREATLY LIMIT RAIN CHANCES...BUT LOW LEVEL MOISTURE TRANSPORT
COULD BE SUFFICIENT TO PRODUCE ISOLATED SHOWER ACTIVITY OVER NE LA/SW
MS THIS AFTN PER RECENT HRRR AND OTHER HIGH RES NEAR TERM GUIDANCE.
THIS PATTERN WILL BRING MUCH MILDER LOW TEMPERATURES TO THE
ARKLAMISS WITH READINGS EXPECTED TO BE ~ 15 DEG F ABOVE CLIMATE
NORMALS. HIGH TEMPERATURES WILL BE WARMER THAN RECENTLY
OBSERVED...BUT THE WARMTH SHOULD BE TEMPERED SOME BY INCREASING
STRATOCUMULUS COVERAGE AND ESE FLOW EMANATING FROM A SLIGHTLY COOLER
AIRMASS WEDGING AROUND THE SOUTHERN APPALACHIANS. STILL EXPECT HIGHS
TO BE 5 TO 10 DEG ABOVE CLIMATOLOGY ON AVERAGE...BUT A FEW COOLER
POCKETS WILL BE POSSIBLE WHERE CLOUD COVER IS MORE PERSISTENT...
ESPECIALLY OVER EAST CENTRAL MS. /EC/
LONG TERM (FRIDAY THROUGH NEXT TUESDAY)...THE PRIMARY CONCERN IN THE
EXTENDED IS PRECIP TIMING FOR LATE THIS WEEK INTO NEXT WEEK.
AT THE BEGINNING OF THE PERIOD, AN UPPER TROUGH EXTENDING FROM
HUDSON BAY INTO THE NORTHERN PLAINS WILL BE IN THE PROCESS OF
CUTTING OFF AN UPPER LOW OVER CALIFORNIA/NEVADA. A SLOW MOVING COLD
FRONT WILL BE POSITIONED FROM THE GREAT LAKES THROUGH THE MID
MISSISSIPPI VALLEY TO THE RED RIVER VALLEY, WITH CONSIDERABLE RAIN
ONGOING IN THOSE AREAS.
HEADING INTO THE WEEKEND, CONSIDERABLE TIMING/PATTERN INCONGRUITIES
REMAIN AMONG OP/ENSEMBLE MODEL GUIDANCE, THUS DID NOT STRAY FAR FROM
ENSEMBLE MEAN AND MODEL BLEND POPS. AT THIS TIME IT APPEARS
ELONGATED MID LEVEL RIDGING AND (AT LEAST IN THE EASTERN HALF OF THE
AREA) WEDGING SURFACE HIGH PRESSURE WILL HELP DEFLECT PRECIP LARGELY
TO THE NORTHWEST THROUGH FRIDAY - MEANING DRY CONDITIONS FOR POST-
THANKSGIVING BARGAIN HUNTERS. SUBTLE IMPULSES EMBEDDED WITHIN AN
UPPER LEVEL SOUTHWESTERLY FLOW REGIME WILL ULTIMATELY ACT TO LOWER
HEIGHTS INTO THE WEEKEND. AS A RESULT, RAIN CHANCES WILL BEGIN TO
CLIMB, ESPECIALLY IN THE NORTHWEST BY SATURDAY WITH MORE WIDESPREAD
COVERAGE POSSIBLE SUNDAY AS A STRONGER DISTURBANCE IS EXPECTED TO
MOVE THROUGH.
THROUGH THE WEEKEND INTO EARLY NEXT WEEK, THE CUTOFF UPPER LOW WILL
MIGRATE INTO THE UPPER PLAINS. AS THE UPPER JET REMAINS NORTH OF THE
REGION ALMOST PARALLEL TO THE SURFACE FRONT, THE FRONT WILL ONLY
MEANDER INTO THE AREA THROUGH EARLY NEXT WEEK, GRADUALLY WEAKENING
WITH THE LOSS OF UPPER SUPPORT. HOWEVER, ABOVE AVERAGE PW IN THE 1
TO 1.5 INCH RANGE WILL STILL EXIST ACROSS THE AREA, KEEPING THE
POSSIBILITY FOR SCATTERED SHOWERS AROUND INTO EARLY NEXT WEEK.
THROUGHOUT THE ENTIRE PERIOD, ONLY ISOLATED TO LOWER END CHANCE POPS
WILL BE INCLUDED ACROSS THE PINE BELT AS THE FRONT LOOKS TO REMAIN
FARTHEST AWAY FROM THIS AREA. GUIDANCE CONTINUES TO SHOW LITTLE TO
NO INSTABILITY WITH THIS SYSTEM, THUS WE WILL CONTINUE TO KEEP
THUNDER OUT OF THE FORECAST. /DL/
&&
.PRELIMINARY POINT TEMPS/POPS...
JACKSON 70 54 70 57 / 0 2 5 4
MERIDIAN 67 48 70 52 / 0 1 3 4
VICKSBURG 69 55 74 59 / 0 4 6 7
HATTIESBURG 71 53 72 55 / 0 4 7 4
NATCHEZ 69 57 73 60 / 0 4 6 7
GREENVILLE 67 54 70 59 / 0 3 9 9
GREENWOOD 68 52 70 57 / 0 2 10 4
&&
.JAN WATCHES/WARNINGS/ADVISORIES...
MS...NONE.
LA...NONE.
AR...NONE.
&&
$$
27/28/EC/DL/
AREA FORECAST DISCUSSION
NWS NORTH PLATTE NE
1154 AM CST WED NOV 25 2015
.SYNOPSIS...
ISSUED AT 340 AM CST WED NOV 25 2015
A CONVOLUTED H5 PATTERN CONTINUES TONIGHT ACROSS NOAM WITH A
RIDGE EXTENDING FROM THE NE PACIFIC INTO THE GULF OF ALASKA.
DOWNSTREAM OF THE RIDGE...A TROUGH EXTENDED FROM NRN SASKATCHEWAN
INTO NRN CALIFORNIA. AT THE BASE OF THIS TROUGH...CLOSED LOW
PRESSURE WAS NOTED OVER SWRN OREGON. EAST OF THE TROUGH...A ZONAL
PATTERN EXISTED ACROSS THE REMAINDER OF THE LOWER 48 STATES WITH
THE EXCEPTION OF A PERSISTENT TROUGH WHICH EXTENDED FROM EASTERN
QUEBEC...SWD INTO NEW ENGLAND. AT THE SURFACE...A FRONTAL
BOUNDARY WAS ANCHORED ALONG THE NEBR/SD BORDER AND MARKED THE
LEADING EDGE OF ARCTIC AIR WHICH WAS ENTRENCHED ACROSS THE NRN
PLAINS. READINGS OFF TO THE NORTH WERE IN THE TEENS IN MONTANA
WITH BREEZY NORTHERLY WINDS. SOUTH OF THE FRONT...TEMPERATURES
WERE IN THE 20S TO LOWER 30S WITH THE EXCEPTION SERN NEBRASKA
WHERE 40S AND LOWER 50S WERE COMMON THANKS TO LOW CLOUDS AND A
DECENT INFLUX OF LOW LEVEL MOISTURE PUSHING NORTH FROM EASTERN
KANSAS. FOR NOW...THE STRATUS AND LOW LEVEL MOISTURE HAS STAYED
JUST OFF TO THE EAST AND SOUTHEAST OF THE FORECAST AREA AND
SHOULD REMAIN THERE BASED ON THE LATEST HRRR FORECAST.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 340 AM CST WED NOV 25 2015
FOR TODAY AND TONIGHT...THE MAIN FORECAST CHALLENGE WILL BE THE
THREAT FOR A WINTRY MIX OF PCPN BEGINNING TONIGHT. FOR
TODAY...THE ARCTIC COLD FRONT WILL PUSH SOUTH THIS MORNING AND
WILL CLEAR MOST OF THE FORECAST AREA BY MID AFTERNOON. HIGHS
TODAY WILL STRUGGLE TO GET OUT OF THE 30S IN THE
NORTHWEST...WHILE 40S ELSEWHERE REMAIN ON TRACK FOR THE FORECAST.
LIKE YESTERDAY...THERE WAS A LARGE DISPARITY IN HIGH TEMPERATURES
BETWEEN THE MAV AND MET GUIDANCE. THE MET SEEMED TOO COOL FOR
NORTH PLATTE TODAY WITH ITS HIGH OF 38 GIVEN THE LATER FRONTAL
TIMING OF EARLY AFTERNOON AND TRENDED THE TEMP FORECAST MORE
TOWARD THE WARMER MAV GUIDANCE. HOWEVER DID NOT GO WITH HIGHS AS
WARM AS THE MAV GUIDANCE SUGGESTS. THIS WAS DUE TO AN ABUNDANCE
OF MID AND HIGH LEVEL CLOUD COVER EXPECTED TODAY IN ADVANCE OF
THE APPG COLD FRONT.
TONIGHT...LOW LEVEL MOISTURE WILL INCREASE BEHIND THE EXITING
COLD FRONT AS A SHIELD OF STRATUS DEVELOPS ACROSS WESTERN AND
NORTH CENTRAL NEBRASKA. ABOVE THE STRATUS...A DECENT DRY LAYER
WILL EXIST WITH SOME WEAK LIFT NOTED JUST ABOVE THE STRATUS LAYER
OVERNIGHT. A THOROUGH EXAMINATION OF BUFKIT FORECAST SOUNDINGS
INDICATES A DECENT SETUP FOR FREEZING DRIZZLE TONIGHT...ROUGHLY
EAST OF A LINE FROM SPRINGVIEW TO OGALLALA. WEST OF THIS
LINE...TEMPERATURE PROFILES IN THE MOIST LAYER SEEM TOO COLD FOR
THE DEVELOPMENT OF FREEZING DRIZZLE AND HAVE OPTED FOR A MENTION
OF SNOW AS THERE IS SOME INDICATION OF MID LEVEL
MOISTENING...ESPECIALLY OVER NORTHWESTERN PORTIONS OF THE CWA
OVERNIGHT. EVEN WITH THE MID LEVEL MOISTENING...THE BEST MOISTURE
IS NOT COLLOCATED WITH THE BEST DENDRITIC TEMPERATURES...SO ANY
SNOW WILL BE VERY LIGHT IN NATURE. ACROSS THE FAR SOUTHEASTERN
CWA...TEMPS WILL BE WARM TO SUPPORT DRIZZLE OR VERY LIGHT RAIN
EARLY THIS EVENING...FOLLOWED BY AREAS OF FREEZING DRIZZLE
OVERNIGHT. LOW LEVEL MOISTURE WILL BE MOST FAVORABLE FOR MORE
WIDESPREAD FREEZING DRIZZLE OVERNIGHT ACROSS FRONTIER AND FAR
SERN CUSTER COUNTY OVERNIGHT...AS IT FLOWS NORTH INTO NEBRASKA
FROM KANSAS. WITH THIS IN MIND...HAVE DECIDED TO PLACE FRONTIER
COUNTY IN A WINTER WEATHER ADVISORY AS QPF FORECASTS ARE
INDICATIVE OF UP TO A FEW HUNDREDTHS OF AN INCH OF FREEZING PCPN.
HOWEVER...ATTM...THE GREATEST THREAT FOR ACCUMULATING FREEZING
PCPN APPEARS TO BE WELL EAST OF THE FORECAST AREA MORE INTO
THURSDAY. WILL RUN THE ADVISORY FROM MIDNIGHT CST TONIGHT THROUGH
6 PM CST THURSDAY.
.LONG TERM...(THURSDAY THROUGH TUESDAY)
ISSUED AT 340 AM CST WED NOV 25 2015
THE THANKSGIVING HOLIDAY TRAVEL EXPECTED TO BE IMPACTED ACROSS
MUCH OF THE AREA. A UPPER LEVEL LOW CUTS OFF ACROSS SW CONUS WITH
A POSITIVELY TILTED TROUGH ACROSS THE NORTHERN PLAINS. AT THE SFC
A COLD FRONT WILL BE EAST OF THE CWA WITH ARCTIC HIGH PRESSURE
BUILDING ACROSS THE ROCKIES. THE MAIN CONCERN FOR THE DAY ON
THURSDAY WILL BE THE LOWER LEVEL TEMP PROFILE AND THE POCKET OF
MID LEVEL DRY AIR. THE LATEST MODELS HAVE TRENDED SLIGHTLY
FURTHER EAST WITH THE COLD AIR AND BUFKIT SOUNDINGS NOW
SUGGESTING BY 12Z THE LOWER PROFILE ALL BELOW ZERO C AND HAVE
FORECAST NOW ALL SNOW. LIFT IS MARGINAL AND WILL BATTLE A POCKET
OF DRY AIR...SO EXPECT SNOW TO BE LIGHT AND WILL HAVE TO MONITOR
THE LEVEL OF DRYNESS AS PRECIP COULD SEE A MIX OF FREEZING
DRIZZLE HOWEVER NOT MENTIONED AT THIS TIME. THROUGH THE DAY
ACCUMULATION WILL BE LIGHT...LESS THAN AN INCH. AS FOR
TEMPS...THE COLD AIR ADVECTION AND PERSISTENT CLOUDS WILL LIMIT
WARMING. GUIDANCE SUGGEST TEMPS REBOUND A FEW DEGREES...HOWEVER
WOULD NOT BE SURPRISED IF TEMPS HELD STEADY OR EVEN FELL DURING
THE AFTERNOON. STILL WELL BELOW NORMAL WITH HIGHS IN THE MID TO
UPPER 20S.
COLD HIGH PRESSURE BUILDS ACROSS THE NORTHERN CWA THURSDAY NIGHT
INTO FRIDAY. THIS WILL USHER IN SOME DRY AIR AND CONFINE ANY SNOW
ACTIVITY TO THE SOUTHERN CWA...WHICH MAY NEED TO BE PUSHED
FURTHER SOUTH PENDING STRENGTH OF THE HIGH. LOWS ON THE COLD
SIDE...SINGLE DIGITS AND TEENS...REBOUNDING ONLY TO THE
20S...MAYBE 30 FOR FRIDAY.
OVER THE WEEKEND THE LOW WILL LIFT NORTH ACROSS THE ROCKIES AS
THE SFC HIGH SHIFTS EAST. RECYCLED COLD AIR WILL WRAP AROUND THE
HIGH AND OVER THE AREA. ALSO GOING TO SEE THE DRY AIR GET PUSHED
EAST WITH A LITTLE BETTER MOISTURE AND A RETURN TO AT LEAST A
SLIGHT CHANCE FOR LIGHT SNOW. THE LATEST EC BROUGHT A DISTURBANCE
AHEAD OF THE UPPER LEVEL LOW AND PRODUCED A BRIEF PERIOD OF
MODERATE SNOW SATURDAY NIGHT. WILL KEEP POPS LOW FOR NOW AND MAKE
A NOTE TO WATCH CAREFULLY.
EARLY NEXT WEEK THE UPPER LOW WILL SLIDE EAST ACROSS THE NORTHERN
PLAINS. COLD AIR REMAINS IN PLACE...HOWEVER COULD SEE SOME MORE
SUN AND HIGHS REBOUNDING INTO THE 30S. A CHANCE FOR SNOW MONDAY
REMAINS IN THE FORECAST...HOWEVER AS THE UPPER LEVEL LOW PUSHES
EAST THE CHANCE FOR ANY PRECIP DIMINISHES THROUGH MID WEEK.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z THURSDAY AFTERNOON)
ISSUED AT 1154 AM CST WED NOV 25 2015
DETERIORATING FLIGHT CONDITIONS ARE ANTICIPATED ACROSS ALL WEST
CENTRAL NEBRASKA TERMINALS THIS EVENING AND OVERNIGHT. THE MODEL
CONSENSUS GENERALLY CALLS FOR A PERIOD OF LIGHT FREEZING DRIZZLE
TO BE FOLLOWED BY LIGHT SNOW. ACCUMULATIONS ARE EXPECTED TO BE
LIGHT..BUT NORTHERLY WIND GUSTS TO 20KTS WILL HELP FURTHER REDUCE
VISIBILITY. FORECAST CONFIDENCE IN TIMING OF THE ONSET OF
PRECIPITATION IS LOWER THAN AVERAGE...BUT THERE/S HIGH CONFIDENCE
THAT THE PRECIPITATION WILL OCCUR.
&&
.LBF WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY FROM MIDNIGHT TONIGHT TO 6 PM CST
THURSDAY FOR NEZ071.
&&
$$
SYNOPSIS...BUTTLER
SHORT TERM...BUTTLER
LONG TERM...MASEK
AVIATION...JACOBS
AREA FORECAST DISCUSSION
NWS LAS VEGAS NV
1050 AM PST WED NOV 25 2015
.SYNOPSIS...A COLD FRONT WILL PUSH SOUTH ACROSS THE REGION
TODAY BRINGING MUCH COLDER TEMPERATURES TO THE REGION ALONG WITH A
FEW SHOWERS TO THE SOUTHERN GREAT BASIN. COLDER AIR WILL STICK
AROUND THROUGH THE HOLIDAY WEEKEND. OCCASIONAL PERIODS OF SHOWERS
ARE EXPECTED IN THE HIGHER TERRAIN OF THE SOUTHERN GREAT BASIN AND
THE SIERRA THROUGH SUNDAY. THERE IS SOME POTENTIAL FOR SHOWERS
ACROSS OTHER PARTS OF THE AREA ON SUNDAY.
&&
.UPDATE...I DID A QUICK UPDATE TO THE GRIDS TO LOWER SNOW LEVELS AND
BRING A RAIN/SNOW MIX IN PARTS OF CLARK AND SOUTHERN NYE COUNTIES AS
THE BAND OF SHOWERS HAS RESULTED IN A LITTLE SNOW MIXING IN WITH
RAIN IN INDIAN SPRINGS AND PAHRUMP. WE MAY ALSO SEE SOMETHING
SIMILAR IN THE EASTERN FOOTHILLS OF THE SPRING MOUNTAINS AND FAR
WEST SIDE OF THE LAS VEGAS VALLEY DEPENDING ON HOW INTENSE THE BAND
IS AT IT MOVES ON IN THE NEXT HOUR OR TWO.
&&
.PREVIOUS UPDATE...
ISSUED AT 953 AM PST WED NOV 25 2015
.UPDATE...A COLD FRONT EXTENDED FROM LINCOLN COUNTY TOWARD THE
CLARK/SOUTHERN NYE BORDER AND SOUTHWEST TOWARD MALIBU, CALIFORNIA.
THE FRONT JUST PASSED THROUGH DESERT ROCK SHIFTING WINDS TO THE
NORTHEAST. KESX RADAR IS FINALLY GETTING LOWER TOPPED PRECIPITATION
INTO RADAR BEAM RANGE AND THUS WE ARE SEEING SOME LIGHT RETURNS.
DESERT ROCK ASOS DID REPORT A TRACE OF RAIN AS THIS BAND PASSED
THROUGH. THE RADAR IS OVERSHOOTING SHOWERS ACROSS LINCOLN COUNTY AS
ELY HAS HAD SIMILAR CLOUDTOPS ON INFRARED SATELLITE AND REPORTED
MODERATE SNOW. SO WE SHOULD SEE SOME LIGHT ACCUMULATIONS ESPECIALLY
NORTH OF PIOCHE AS THIS BAND OF SHOWERS MOVES ON THROUGH. I ADJUSTED
THE POP GRIDS TO ACCOUNT FOR THE LATEST TRENDS ON SATELLITE AND
RADAR.
THE HRRR SEEMS TO REALLY SLOW THE WIND SHIFT DOWN WITH THE FRONT IN
THE LAS VEGAS VALLEY. THIS MAY BE A FRONT THAT GETS A WIND SHIFT
MUCH QUICKER IN AREAS NORTH OF SAHARA AVENUE AND SOUTH OF THAT SEES
A DELAY FOR WINDS TO GO NORTHWEST. EITHER WAY OBS UPSTREAM SHOW
WINDS TANKING IN STRENGTH BEHIND THE FRONT AND WINDS WILL DECREASE
IN THE LAS VEGAS VALLEY BY THIS AFTERNOON.
THE REST OF THE FORECAST LOOKS FINE AT THIS TIME.
&&
.PREVIOUS DISCUSSION...
ISSUED AT 451 AM PST WED NOV 25 2015
.SHORT TERM...THROUGH FRIDAY NIGHT.
WINDS SHOULD BEGIN TO DECREASE AS A COLD FRONT PUSHES SOUTH ACROSS
THE REGION TODAY. THE MAIN HIGHLIGHT WITH THIS FEATURE WILL BE THE
SIGNIFICANTLY COLDER AIR (15-20 DEGREES COOLER THAN YESTERDAY) THAT
WILL SPREAD ACROSS THE REGION...REMAINING IN PLACE INTO THE HOLIDAY
WEEKEND WITH THE UPPER LEVEL LOW MEANDERING OVER THE GREAT BASIN.
RAIN AND MOUNTAIN SNOW SHOWERS MAY ALSO ACCOMPANY THE FRONT...BUT
AMOUNTS ARE EXPECTED TO REMAIN LIGHT. THE BEST CHANCES FOR SHOWERS
WILL BE ACROSS LINCOLN COUNTY TODAY. THE FOCUS THEN TURNS TO
OVERNIGHT TEMPERATURES WHICH WILL LIKELY FALL INTO THE 30`S IN THE
LAS VEGAS VALLEY AND NORTHEAST CLARK COUNTY THE NEXT COUPLE OF
NIGHTS. A FREEZE WATCH REMAINS IN PLACE FOR THESE AREAS SINCE
CONFIDENCE IN TEMPERATURES REACHING THE FREEZING MARK IS LOW AT THIS
TIME.
.LONG TERM...SATURDAY THROUGH WEDNESDAY.
BY SATURDAY MORNING...A REX BLOCK WILL BE FIRMLY IN PLACE ACROSS THE
REGION WITH A MID-LARGE UPPER LEVEL LOW PARKED OVER THE SOUTHERN
GREAT BASIN. THIS WILL KEEP CLOUDY AND COOL CONDITIONS AROUND
THROUGH MUCH OF THE WEEKEND...WITH AFTERNOON HIGHS GENERALLY RUNNING
8-12 DEGREES BELOW AVERAGE FOR LATE NOVEMBER. HOWEVER...AS DISCUSSED
IN YESTERDAY AFTERNOON`S AFD...THE FORECAST CONCERN FOR THIS PERIOD
CONTINUES TO BE WHETHER THERE WILL BE ENOUGH MOISTURE PRESENT FOR
PRECIPITATION OR NOT. OPERATIONAL MODEL GUIDANCE AND THEIR
ASSOCIATED ENSEMBLES GENERALLY AGREE IN A SECONDARY SHORTWAVE
GETTING PULLED INTO THE MAIN UPPER LOW SATURDAY AFTERNOON - SUNDAY
MORNING TIMEFRAME. SOME TIMING DIFFERENCES DO EXIST BETWEEN THE 00Z
GFS AND ECMWF SOLUTIONS...WITH THE GFS RUNNING ABOUT 12-18 HOURS
QUICKER IN BRINGING THE SECONDARY SHORTWAVE ACROSS THE REGION. LIKE
THE 12Z RUN...THE LATEST RUN OF THE GFS CONTINUES TO AGGRESSIVELY
EMPHASIZE THE AMOUNT MOISTURE ASSOCIATED WITH THIS FEATURE AS IT
ROTATES AROUND THE BASE OF THE LOW. AS A RESULT...DECIDED TO FAVOR
THE LESS AGGRESSIVE ECMWF SOLUTION...WHICH DOES INDICATE SUFFICIENT
MID-LEVEL MOISTURE WITH THIS FEATURE. THEREFORE...CONTINUED TO
MENTION SLIGHT CHANCE POPS FOR THE SATURDAY AFTERNOON-SUNDAY MORNING
TIMEFRAME...MAINLY ACROSS THE SOUTHERN GREAT BASIN ZONES. IT WILL BE
INTERESTING TO SEE HOW FUTURE MODEL RUNS EVOLVE WITH RESPECT TO
TIMING THIS SHORTWAVE AND HOW MUCH MOISTURE WILL BE ASSOCIATED WITH
IT.
THERE IS FAIRLY CONSISTENT AGREEMENT IN ANOTHER PIECE OF ENERGY
BREAKING OFF FROM THE GULF OF ALASKA LOW AND DEVELOPING A KICKER LOW
OVER THE EASTERN PACIFIC THAT WILL HELP TO BREAK THE REX BLOCK
PATTERN OVER THE REGION. UNFORTUNATELY...THAT IS THE EXTENT OF MODEL
CONSENSUS FOR THE TIME BEING...AS EACH OPERATIONAL MODEL HANDLES THE
EVOLUTION OF THIS FEATURE DIFFERENTLY...RESULTING IN A LOW
CONFIDENCE FORECAST. AS A RESULT...CONTINUED MOSTLY WITH WHAT WAS
INHERITED IN THE GRIDS FOR MONDAY THROUGH WEDNESDAY MORNING...WITH
THE CHANCES OF CONTINUED BELOW AVERAGE TEMPERATURES LOOKING HIGH FOR
MUCH OF THE AREA.
&&
.AVIATION...FOR MCCARRAN...SOUTHWEST WINDS WITH GUSTS OF 20-30 KTS
AND AREAS OF MECHANICAL TURBULENCE WILL CONTINUE THROUGH THE REST OF
THE MORNING BEFORE A COLD FRONT MOVES INTO THE LAS VEGAS VALLEY
BETWEEN 19-21Z. THIS FRONT WILL TURN THE WINDS TO THE NORTHWEST...AT
LEAST BRIEFLY. WINDS MAY RETURN TO A MORE WEST TO SOUTHWEST
DIRECTION LATER IN THE AFTERNOON OR EARLY EVENING AS THE IMPACT FROM
THE COLD FRONT DIMINISHES. FEW-SCT CLOUDS AOA 8K FEET ARE EXPECTED
THROUGH THE PERIOD. LIGHTER WINDS ARE EXPECTED THROUGH THURSDAY.
FOR THE REST OF SOUTHERN NEVADA...NORTHWEST ARIZONA...AND SOUTHEAST
CALIFORNIA...GUSTY SOUTHWEST WINDS WILL GIVE WAY TO NORTHWESTERLY
WINDS AS A COLD FRONT PUSHES THROUGH THE REGION TODAY. THE FRONT
WILL DIMINISH IN STRENGTH AS IT MOVES THROUGH THE LAS VEGAS VALLEY.
EXPECT SOME WEAK SHOWER ACTIVITY NEAR THE FRONT AS IT MOVES THROUGH
THE SOUTHERN GREAT BASIN. LIGHTER WINDS ARE EXPECTED ACROSS THE
REGION THURSDAY. SCT-BKN CLOUDS MAINLY AOA 6-8K FEET THROUGH THE
PERIOD...ALONG WITH MECHANICAL TURBULENCE NEAR THE HIGH TERRAIN.
&&
$$
UPDATE...STACHELSKI
SHORT TERM/AVIATION...WOLCOTT
LONG TERM...PULLIN
FOR MORE FORECAST INFORMATION...SEE US ON OUR WEBPAGE:
HTTP://WEATHER.GOV/LASVEGAS OR FOLLOW US ON FACEBOOK AND TWITTER
AREA FORECAST DISCUSSION
NWS LAS VEGAS NV
953 AM PST WED NOV 25 2015
.SYNOPSIS...A COLD FRONT WILL PUSH SOUTH ACROSS THE REGION
TODAY BRINGING MUCH COLDER TEMPERATURES TO THE REGION ALONG WITH A
FEW SHOWERS TO THE SOUTHERN GREAT BASIN. COLDER AIR WILL STICK
AROUND THROUGH THE HOLIDAY WEEKEND. OCCASIONAL PERIODS OF SHOWERS
ARE EXPECTED IN THE HIGHER TERRAIN OF THE SOUTHERN GREAT BASIN AND
THE SIERRA THROUGH SUNDAY. THERE IS SOME POTENTIAL FOR SHOWERS
ACROSS OTHER PARTS OF THE AREA ON SUNDAY.
&&
.UPDATE...A COLD FRONT EXTENDED FROM LINCOLN COUNTY TOWARD THE
CLARK/SOUTHERN NYE BORDER AND SOUTHWEST TOWARD MALIBU, CALIFORNIA.
THE FRONT JUST PASSED THROUGH DESERT ROCK SHIFTING WINDS TO THE
NORTHEAST. KESX RADAR IS FINALLY GETTING LOWER TOPPED PRECIPITATION
INTO RADAR BEAM RANGE AND THUS WE ARE SEEING SOME LIGHT RETURNS.
DESERT ROCK ASOS DID REPORT A TRACE OF RAIN AS THIS BAND PASSED
THROUGH. THE RADAR IS OVERSHOOTING SHOWERS ACROSS LINCOLN COUNTY AS
ELY HAS HAD SIMILAR CLOUDTOPS ON INFRARED SATELLITE AND REPORTED
MODERATE SNOW. SO WE SHOULD SEE SOME LIGHT ACCUMULATIONS ESPECIALLY
NORTH OF PIOCHE AS THIS BAND OF SHOWERS MOVES ON THROUGH. I ADJUSTED
THE POP GRIDS TO ACCOUNT FOR THE LATEST TRENDS ON SATELLITE AND
RADAR.
THE HRRR SEEMS TO REALLY SLOW THE WIND SHIFT DOWN WITH THE FRONT IN
THE LAS VEGAS VALLEY. THIS MAY BE A FRONT THAT GETS A WIND SHIFT
MUCH QUICKER IN AREAS NORTH OF SAHARA AVENUE AND SOUTH OF THAT SEES
A DELAY FOR WINDS TO GO NORTHWEST. EITHER WAY OBS UPSTREAM SHOW
WINDS TANKING IN STRENGTH BEHIND THE FRONT AND WINDS WILL DECREASE
IN THE LAS VEGAS VALLEY BY THIS AFTERNOON.
THE REST OF THE FORECAST LOOKS FINE AT THIS TIME.
&&
.PREVIOUS DISCUSSION...
ISSUED AT 451 AM PST WED NOV 25 2015
.SHORT TERM...THROUGH FRIDAY NIGHT.
WINDS SHOULD BEGIN TO DECREASE AS A COLD FRONT PUSHES SOUTH ACROSS
THE REGION TODAY. THE MAIN HIGHLIGHT WITH THIS FEATURE WILL BE THE
SIGNIFICANTLY COLDER AIR (15-20 DEGREES COOLER THAN YESTERDAY) THAT
WILL SPREAD ACROSS THE REGION...REMAINING IN PLACE INTO THE HOLIDAY
WEEKEND WITH THE UPPER LEVEL LOW MEANDERING OVER THE GREAT BASIN.
RAIN AND MOUNTAIN SNOW SHOWERS MAY ALSO ACCOMPANY THE FRONT...BUT
AMOUNTS ARE EXPECTED TO REMAIN LIGHT. THE BEST CHANCES FOR SHOWERS
WILL BE ACROSS LINCOLN COUNTY TODAY. THE FOCUS THEN TURNS TO
OVERNIGHT TEMPERATURES WHICH WILL LIKELY FALL INTO THE 30`S IN THE
LAS VEGAS VALLEY AND NORTHEAST CLARK COUNTY THE NEXT COUPLE OF
NIGHTS. A FREEZE WATCH REMAINS IN PLACE FOR THESE AREAS SINCE
CONFIDENCE IN TEMPERATURES REACHING THE FREEZING MARK IS LOW AT THIS
TIME.
.LONG TERM...SATURDAY THROUGH WEDNESDAY.
BY SATURDAY MORNING...A REX BLOCK WILL BE FIRMLY IN PLACE ACROSS THE
REGION WITH A MID-LARGE UPPER LEVEL LOW PARKED OVER THE SOUTHERN
GREAT BASIN. THIS WILL KEEP CLOUDY AND COOL CONDITIONS AROUND
THROUGH MUCH OF THE WEEKEND...WITH AFTERNOON HIGHS GENERALLY RUNNING
8-12 DEGREES BELOW AVERAGE FOR LATE NOVEMBER. HOWEVER...AS DISCUSSED
IN YESTERDAY AFTERNOON`S AFD...THE FORECAST CONCERN FOR THIS PERIOD
CONTINUES TO BE WHETHER THERE WILL BE ENOUGH MOISTURE PRESENT FOR
PRECIPITATION OR NOT. OPERATIONAL MODEL GUIDANCE AND THEIR
ASSOCIATED ENSEMBLES GENERALLY AGREE IN A SECONDARY SHORTWAVE
GETTING PULLED INTO THE MAIN UPPER LOW SATURDAY AFTERNOON - SUNDAY
MORNING TIMEFRAME. SOME TIMING DIFFERENCES DO EXIST BETWEEN THE 00Z
GFS AND ECMWF SOLUTIONS...WITH THE GFS RUNNING ABOUT 12-18 HOURS
QUICKER IN BRINGING THE SECONDARY SHORTWAVE ACROSS THE REGION. LIKE
THE 12Z RUN...THE LATEST RUN OF THE GFS CONTINUES TO AGGRESSIVELY
EMPHASIZE THE AMOUNT MOISTURE ASSOCIATED WITH THIS FEATURE AS IT
ROTATES AROUND THE BASE OF THE LOW. AS A RESULT...DECIDED TO FAVOR
THE LESS AGGRESSIVE ECMWF SOLUTION...WHICH DOES INDICATE SUFFICIENT
MID-LEVEL MOISTURE WITH THIS FEATURE. THEREFORE...CONTINUED TO
MENTION SLIGHT CHANCE POPS FOR THE SATURDAY AFTERNOON-SUNDAY MORNING
TIMEFRAME...MAINLY ACROSS THE SOUTHERN GREAT BASIN ZONES. IT WILL BE
INTERESTING TO SEE HOW FUTURE MODEL RUNS EVOLVE WITH RESPECT TO
TIMING THIS SHORTWAVE AND HOW MUCH MOISTURE WILL BE ASSOCIATED WITH
IT.
THERE IS FAIRLY CONSISTENT AGREEMENT IN ANOTHER PIECE OF ENERGY
BREAKING OFF FROM THE GULF OF ALASKA LOW AND DEVELOPING A KICKER LOW
OVER THE EASTERN PACIFIC THAT WILL HELP TO BREAK THE REX BLOCK
PATTERN OVER THE REGION. UNFORTUNATELY...THAT IS THE EXTENT OF MODEL
CONSENSUS FOR THE TIME BEING...AS EACH OPERATIONAL MODEL HANDLES THE
EVOLUTION OF THIS FEATURE DIFFERENTLY...RESULTING IN A LOW
CONFIDENCE FORECAST. AS A RESULT...CONTINUED MOSTLY WITH WHAT WAS
INHERITED IN THE GRIDS FOR MONDAY THROUGH WEDNESDAY MORNING...WITH
THE CHANCES OF CONTINUED BELOW AVERAGE TEMPERATURES LOOKING HIGH FOR
MUCH OF THE AREA.
&&
.AVIATION...FOR MCCARRAN...SOUTHWEST WINDS WITH GUSTS OF 20-30 KTS
AND AREAS OF MECHANICAL TURBULENCE WILL CONTINUE THROUGH THE REST OF
THE MORNING BEFORE A COLD FRONT MOVES INTO THE LAS VEGAS VALLEY
BETWEEN 19-21Z. THIS FRONT WILL TURN THE WINDS TO THE NORTHWEST...AT
LEAST BRIEFLY. WINDS MAY RETURN TO A MORE WEST TO SOUTHWEST
DIRECTION LATER IN THE AFTERNOON OR EARLY EVENING AS THE IMPACT FROM
THE COLD FRONT DIMINISHES. FEW-SCT CLOUDS AOA 8K FEET ARE EXPECTED
THROUGH THE PERIOD. LIGHTER WINDS ARE EXPECTED THROUGH THURSDAY.
FOR THE REST OF SOUTHERN NEVADA...NORTHWEST ARIZONA...AND SOUTHEAST
CALIFORNIA...GUSTY SOUTHWEST WINDS WILL GIVE WAY TO NORTHWESTERLY
WINDS AS A COLD FRONT PUSHES THROUGH THE REGION TODAY. THE FRONT
WILL DIMINISH IN STRENGTH AS IT MOVES THROUGH THE LAS VEGAS VALLEY.
EXPECT SOME WEAK SHOWER ACTIVITY NEAR THE FRONT AS IT MOVES THROUGH
THE SOUTHERN GREAT BASIN. LIGHTER WINDS ARE EXPECTED ACROSS THE
REGION THURSDAY. SCT-BKN CLOUDS MAINLY AOA 6-8K FEET THROUGH THE
PERIOD...ALONG WITH MECHANICAL TURBULENCE NEAR THE HIGH TERRAIN.
&&
$$
UPDATE...STACHELSKI
SHORT TERM/AVIATION...WOLCOTT
LONG TERM...PULLIN
FOR MORE FORECAST INFORMATION...SEE US ON OUR WEBPAGE:
HTTP://WEATHER.GOV/LASVEGAS OR FOLLOW US ON FACEBOOK AND TWITTER
AREA FORECAST DISCUSSION
NWS LAS VEGAS NV
933 AM PST WED NOV 25 2015
.SYNOPSIS...A COLD FRONT WILL PUSH SOUTH ACROSS THE REGION
TODAY BRINGING MUCH COLDER TEMPERATURES TO THE REGION ALONG WITH A
FEW SHOWERS TO THE SOUTHERN GREAT BASIN. COLDER AIR WILL STICK
AROUND THROUGH THE HOLIDAY WEEKEND. OCCASIONAL PERIODS OF SHOWERS
ARE EXPECTED IN THE HIGHER TERRAIN OF THE SOUTHERN GREAT BASIN AND
THE SIERRA THROUGH SUNDAY. THERE IS SOME POTENTIAL FOR SHOWERS
ACROSS OTHER PARTS OF THE AREA ON SUNDAY.
&&
.UPDATE...A COLD FRONT EXTENDED FROM LINCOLN COUNTY TOWARD THE
CLARK/SOUTHERN NYE BORDER AND SOUTHWEST TOWARD MALIBU, CALIFORNIA.
THE FRONT JUST PASSED THROUGH DESERT ROCK SHIFTING WINDS TO THE
NORTHEAST. KESX RADAR IS FINALLY GETTING LOWER TOPPED PRECIPITATION
INTO RADAR BEAM RANGE AND THUS WE ARE SEEING SOME LIGHT RETURNS.
DESERT ROCK ASOS DID REPORT A TRACE OF RAIN AS THIS BAND PASSED
THROUGH. THE RADAR IS OVERSHOOTING SHOWERS ACROSS LINCOLN COUNTY AS
ELY HAS HAD SIMILAR CLOUDTOPS ON INFRARED SATELLITE AND REPORTED
MODERATE SNOW. SO WE SHOULD SEE SOME LIGHT ACCUMULATIONS ESPECIALLY
NORTH OF PIOCHE AS THIS BAND OF SHOWERS MOVES ON THROUGH. I ADJUSTED
THE POP GRIDS TO ACCOUNT FOR THE LATEST TRENDS ON SATELLITE AND
RADAR.
THE HRRR SEEMS TO REALLY SLOW THE WIND SHIFT DOWN WITH THE FRONT IN
THE LAS VEGAS VALLEY. THIS MAY BE A FRONT THAT GETS A WIND SHIFT
MUCH QUICKER IN AREAS NORTH OF SAHARA AVENUE AND SOUTH OF THAT SEES
A DELAY FOR WINDS TO GO NORTHWEST. EITHER WAY OBS UPSTREAM SHOW
WINDS TANKING IN STRENGTH BEHIND THE FRONT AND WINDS WILL DECREASE
IN THE LAS VEGAS VALLEY BY THIS AFTERNOON.
THE REST OF THE FORECAST LOOKS FINE AT THIS TIME.
&&
.PREVIOUS DISCUSSION...
ISSUED AT 451 AM PST WED NOV 25 2015
.SHORT TERM...THROUGH FRIDAY NIGHT.
WINDS SHOULD BEGIN TO DECREASE AS A COLD FRONT PUSHES SOUTH ACROSS
THE REGION TODAY. THE MAIN HIGHLIGHT WITH THIS FEATURE WILL BE THE
SIGNIFICANTLY COLDER AIR (15-20 DEGREES COOLER THAN YESTERDAY) THAT
WILL SPREAD ACROSS THE REGION...REMAINING IN PLACE INTO THE HOLIDAY
WEEKEND WITH THE UPPER LEVEL LOW MEANDERING OVER THE GREAT BASIN.
RAIN AND MOUNTAIN SNOW SHOWERS MAY ALSO ACCOMPANY THE FRONT...BUT
AMOUNTS ARE EXPECTED TO REMAIN LIGHT. THE BEST CHANCES FOR SHOWERS
WILL BE ACROSS LINCOLN COUNTY TODAY. FOCUS THEN TURNS TO OVERNIGHT
TEMPERATURES WHICH WILL LIKELY FALL INTO THE 30`S IN THE LAS VEGAS
VALLEY AND NORTHEAST CLARK COUNTY THE NEXT COUPLE NIGHT. A FREEZE
WATCH REMAINS IN PLACE FOR THESES AREAS SINCE CONFIDENCE IN
TEMPERATURES REACHING THE FREEZING MARK IS LOW AT THIS TIME.
.LONG TERM...SATURDAY THROUGH WEDNESDAY.
BY SATURDAY MORNING...A REX BLOCK WILL BE FIRMLY IN PLACE ACROSS THE
REGION WITH A MID-LARGE UPPER LEVEL LOW PARKED OVER THE SOUTHERN
GREAT BASIN. THIS WILL KEEP CLOUDY AND COOL CONDITIONS AROUND
THROUGH MUCH OF THE WEEKEND...WITH AFTERNOON HIGHS GENERALLY RUNNING
8-12 DEGREES BELOW AVERAGE FOR LATE NOVEMBER. HOWEVER...AS DISCUSSED
IN YESTERDAY AFTERNOONS AFD...THE FORECAST CONCERN FOR THIS PERIOD
CONTINUES TO BE WHETHER THERE WILL BE ENOUGH MOISTURE PRESENT FOR
PRECIPITATION OR NOT. OPERATIONAL MODEL GUIDANCE AND THEIR
ASSOCIATED ENSEMBLES GENERALLY AGREE IN A SECONDARY SHORTWAVE
GETTING PULLED INTO THE MAIN UPPER LOW SATURDAY AFTERNOON - SUNDAY
MORNING TIMEFRAME. SOME TIMING DIFFERENCES DO EXIST BETWEEN THE 00Z
GFS AND ECMWF SOLUTIONS...WITH THE GFS RUNNING ABOUT 12-18 HOURS
QUICKER IN BRINGING THE SECONDARY SHORTWAVE ACROSS THE REGION. LIKE
THE 12Z RUN...THE LATEST RUN OF THE GFS CONTINUES TO AGGRESSIVELY
EMPHASIZE THE AMOUNT MOISTURE ASSOCIATED WITH THIS FEATURE AS IT
ROTATES AROUND THE BASE OF THE LOW. AS A RESULT...DECIDED TO FAVOR
THE LESS AGGRESSIVE ECMWF SOLUTION...WHICH DOES INDICATE SUFFICIENT
MID-LEVEL MOISTURE WITH THIS FEATURE. THEREFORE...CONTINUED TO
MENTION SLIGHT CHANCE POPS FOR THE SATURDAY AFTERNOON-SUNDAY MORNING
TIMEFRAME...MAINLY ACROSS THE SOUTHERN GREAT BASIN ZONES. IT WILL BE
INTERESTING TO SEE HOW FUTURE MODEL RUNS EVOLVE WITH RESPECT TO
TIMING THIS SHORTWAVE AND HOW MUCH MOISTURE WILL BE ASSOCIATED WITH
IT.
THERE IS FAIRLY CONSISTENT AGREEMENT IN ANOTHER PIECE OF ENERGY
BREAKING OFF FROM THE GULF OF ALASKA LOW AND DEVELOPING A KICKER LOW
OVER THE EASTERN PACIFIC THAT WILL HELP TO BREAK THE REX BLOCK
PATTERN OVER THE REGION. UNFORTUNATELY...THAT IS THE EXTENT OF MODEL
CONSENSUS FOR THE TIME BEING...AS EACH OPERATIONAL MODEL HANDLES THE
EVOLUTION OF THIS FEATURE DIFFERENTLY...RESULTING IN A LOW
CONFIDENCE FORECAST. AS A RESULT...CONTINUED MOSTLY WITH WHAT WAS
INHERITED IN THE GRIDS FOR MONDAY THROUGH WEDNESDAY MORNING...WITH
THE CHANCES OF CONTINUED BELOW AVERAGE TEMPERATURES LOOKING HIGH FOR
MUCH OF THE AREA.
&&
.AVIATION...FOR MCCARRAN...SOUTHWEST WINDS WITH GUSTS OF 20-30 KTS
AND AREAS OF MECHANICAL TURBULENCE WILL CONTINUE THROUGH THE REST OF
THE MORNING BEFORE A COLD FRONT MOVES INTO THE LAS VEGAS VALLEY
BETWEEN 19-21Z. THIS FRONT WILL TURN THE WINDS TO THE NORTHWEST...AT
LEAST BRIEFLY. WINDS MAY RETURN TO A MORE WEST TO SOUTHWEST
DIRECTION LATER IN THE AFTERNOON OR EARLY EVENING AS THE IMPACT FROM
THE COLD FRONT DIMINISHES. FEW-SCT CLOUDS AOA 8K FEET ARE EXPECTED
THROUGH THE PERIOD. LIGHTER WINDS ARE EXPECTED THROUGH THURSDAY.
FOR THE REST OF SOUTHERN NEVADA...NORTHWEST ARIZONA...AND SOUTHEAST
CALIFORNIA...GUSTY SOUTHWEST WINDS WILL GIVE WAY TO NORTHWESTERLY
WINDS AS A COLD FRONT PUSHES THROUGH THE REGION TODAY. THE FRONT
WILL DIMINISH IN STRENGTH AS IT MOVES THROUGH THE LAS VEGAS VALLEY.
EXPECT SOME WEAK SHOWER ACTIVITY NEAR THE FRONT AS IT MOVES THROUGH
THE SOUTHERN GREAT BASIN. LIGHTER WINDS ARE EXPECTED ACROSS THE
REGION THURSDAY. SCT-BKN CLOUDS MAINLY AOA 6-8K FEET THROUGH THE
PERIOD...ALONG WITH MECHANICAL TURBULENCE NEAR THE HIGH TERRAIN.
&&
$$
UPDATE...STACHELSKI
SHORT TERM/AVIATION...WOLCOTT
LONG TERM...PULLIN
FOR MORE FORECAST INFORMATION...SEE US ON OUR WEBPAGE:
HTTP://WEATHER.GOV/LASVEGAS OR FOLLOW US ON FACEBOOK AND TWITTER
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
247 PM EST WED NOV 25 2015
.SYNOPSIS...
STRONG HIGH PRESSURE OVER THE NORTH ATLANTIC WILL CONTROL OUR
WEATHER FOR THE REMAINDER OF THE WEEK. A DRY COLD FRONT WILL DROP
SOUTH ACROSS THE AREA SATURDAY. LOW PRESSURE WILL APPROACH FROM
THE WEST MONDAY AND TUESDAY WITH A SMALL CHANCE FOR SHOWERS
DEVELOPING.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 300 PM WEDNESDAY...VERY HIGH SURFACE PRESSURES IN PLACE OVER THE
CAROLINAS WITH A 1042MB HIGH OFF NEW ENGLAND COAST EXTENDING A RIDGE
AXIS OF 1036MB INTO THE CAROLINAS. PLENTY OF ATLANTIC MOISTURE SEEN
STREAMING SOUTHWESTWARD AND COAST-PARALLEL (IN THE FORM OF CLOUDS
BUT ALSO A FEW BLIPS ON RADAR) IN THIS FLOW BUT THE COOLER NEARSHORE
WATERS HAVE CREATED JUST ENOUGH INSTABILITY AND SUNSHINE HAS LARGELY
PREVAILED. WITH THE LOSS OF DAYTIME HEATING HOWEVER THIS STABILITY
WILL BE OFFSET AND SOME OF THIS MOISTURE SHOULD START MAKING IT
ASHORE ESPECIALLY AS THE LOW LEVEL FLOW VEERS A BIT ATOP THE SURFACE
LAYER. OTHER THAN PERHAPS A SPRINKLE OR TWO MAINLY ALONG THE
PROTRUDING AREAS LIKE BALD HEAD ISLAND/SOUTHPORT AREAS SHOULD STAY
DRY. THIS IS SUPPORTED BY THE GFS AND NEWER RUNS OF THE HRRR WHEREAS
THE OPERATIONAL 12Z WRF ADVECTS SOME VERY LIGHT RAIN FURTHER INLAND,
SEEMINGLY IN ERROR.
&&
.SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/...
AS OF 300 PM WEDNESDAY...A REALLY INTERESTING UPPER LEVEL PATTERN
DEVELOPS THANKSGIVING DAY: AN UPPER RIDGE INTENSIFIES ACROSS THE
SE STATES WHILE A SHORTWAVE DISTURBANCE DIVES SOUTHWARD ACROSS
FLORIDA INTO THE BAHAMAS. THIS DISTURBANCE HELPS CUT OFF A BROAD
UPPER LOW ACROSS THE NORTHERN BAHAMAS WHICH THE GFS/ECMWF BOTH
SINK INTO THE CARIBBEAN SEA NEXT WEEK. THE RIDGE OVER US SHOULD
HELP DISSIPATE ANY CIRRUS ADVECTING EASTWARD FROM STORMINESS IN
THE PLAINS STATES AND WILL MAINTAIN A VERY DRY AIRMASS THROUGHOUT THE
MID AND UPPER LEVELS.
BELOW 800 MB (ABOUT 7000 FEET AGL) ONSHORE FLOW FROM THE ATLANTIC
WILL BRING IN MOISTURE...HOWEVER THE GFS/ECMWF MODELS APPEAR LESS
BULLISH ON THE DEPTH AND TIME WHERE ENOUGH MOISTURE WILL BE
PRESENT FOR CLOUD COVER. WATCHING HOW DIFFICULT A TIME THE
ATLANTIC STRATOCUMULUS HAS HAD PUSHING WESTWARD TODAY GIVES ME
PAUSE TO FORECAST ANYTHING WORSE THAN "PARTLY CLOUDY" THURSDAY.
THE LOW LEVELS SHOULD ACTUALLY DRY OUT SLIGHTLY FRIDAY WHICH
SHOULD LEAD TO MOSTLY SUNNY SKIES.
THE 12Z GFS AND 12Z ECMWF MODELS ARE PREFERRED OVER THE 12Z NAM
GIVEN WHAT APPEARS TO BE BETTER HANDLING OF THE DOMINANCE OF THE
WESTERN ATLANTIC HIGH LATER THIS WEEK. THE NAM IS LIKELY WRONG
WITH ITS DEVELOPING SURFACE LOW PRESSURE BETWEEN BERMUDA AND THE
CAROLINAS...THEN PINWHEELING IT WESTWARD AROUND THE TOPSIDE OF
THE UPPER LOW. IN THE NAM THIS FEATURE DISTORTS OUR LOW-LEVEL WIND
PATTERN AND CREATES COLD ADVECTION THAT DOESN`T APPEAR IN THE
OTHER TWO MODELS. FORECAST HIGHS/LOWS HAVE BEEN ADJUSTED VERY NEAR
THE 12Z GFS/ECMWF VALUES.
&&
.LONG TERM /SATURDAY THROUGH WEDNESDAY/...
AS OF 300 PM WEDNESDAY...AMPLIFIED MID LEVEL PATTERN CONTINUES TO GIVE
MEDIUM RANGE GUIDANCE FITS NEXT WEEK. PERIOD BEGINS WITH FLATTENING
5H RIDGE OVERHEAD WITH SURFACE HIGH EXTENDING DOWN THE EAST COAST.
THIS WILL HELP KEEP THE REGION WARM AND DRY SATURDAY AND SUNDAY. MID
LEVEL PATTERN STARTS TO TRANSITION EARLY NEXT WEEK AS THE CLOSED LOW
OVER THE GREAT BASIN SLOWLY STARTS MOVING EAST. MOISTURE ASSOCIATED
WITH A FRONT STALLED OVER THE LOWER MS VALLEY ON SUN WILL WORK ITS
WAY EAST MON INTO TUE. MOISTURE WILL BE LIMITED BY THE TIME IT
REACHES THE LOCAL AREA AND PRECIP POTENTIAL MON INTO TUE LOOKS
LIMITED. THE FRONT ALSO DRIFTS EAST MON/TUE ENDING UP STALLED IN THE
KY/TN VALLEYS AS SURFACE HIGH ALONG THE EAST COAST HOLDS STRONG.
EVENTUALLY 5H LOW EMERGING FROM THE GREAT BASIN WILL PUSH A COLD
FRONT ACROSS THE AREA LATE IN THE PERIOD BUT THE AMOUNT OF MOISTURE
AND PRESENCE OF MID LEVEL DYNAMICS REMAINS IN QUESTION. GIVEN THE
UNCERTAINTY WILL KEEP POP CAPPED AT LOW CHC THROUGH THE PERIOD.
TEMPERATURES WILL REMAIN ABOVE CLIMO.
&&
.AVIATION /18Z WEDNESDAY THROUGH MONDAY/...
AS OF 18Z...HIGH PRESSURE WILL CONTINUE TO CONTROL THE REGION. A
WEAK COASTAL TROUGH WILL PRODUCE STRATOCU THAT WILL HUG THE COAST
THIS AFTERNOON. A CEILING IS POSSIBLE AT THE MYRTLES...HOWEVER SKIES
WILL REMAIN MOSTLY SCATTERED. NORTHEAST FLOW WILL BECOME GUSTY AFTER
SOLAR INSOLATION STARTS THE MIXING PROCESS. LOOK FOR LIGHT NORTHEAST
FLOW THIS EVENING WITH MAINLY A HIGH CLOUD CEILING. MODELS INTRODUCE
FOG/STRATUS OVERNIGHT. THINK INLAND TERMINALS STAND THE BEST SHOT.
THURSDAY...BECOMING VFR WITH A STRATOCU CEILING ALONG THE COAST.
EXTENDED OUTLOOK...MORNING FOG/STRATUS POSSIBLE FRIDAY. UNSETTLED
WEATHER SATURDAY THROUGH MONDAY WITH A CHANCE OF RAIN EACH DAY.
&&
.MARINE...
NEAR TERM /THROUGH TONIGHT/...
AS OF 300 PM WEDNESDAY...A MODERATELY STRONG GRADIENT IN PLACE DUE TO
SPRAWLING 1042MB HIGH CENTERED OFF NEW ENGLAND COAST EXTENDING A
RIDGE AXIS INTO THE CAROLINAS. PAIR THE STRENGTH OF THIS FEATURE AND
GRADIENT WITH THE BROAD SWATH OF NORTHEASTERLY FLOW ACROSS A LARGE
PORTION OF THE WESTERN ATLANTIC AND THE STAGE IS SET FOR SOME
ADVISORY-WORTHY WINDS AND SEAS. MOST ZONES WILL AVERAGE 4-6 OR
BRIEFLY 5-7 FT THOUGH THERE WILL BE A VERY NEARSHORE WAVE HEIGHT
SHADOW OFF BRUNSWICK COUNTY COAST.
SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/...
AS OF 300 PM WEDNESDAY...1050 MB HIGH PRESSURE OVER NEWFOUNDLAND
WILL MOVE EAST INTO THE NORTH ATLANTIC OCEAN LATER THIS WEEK...
BUT WILL CONTINUE TO EXTEND A RIDGE AXIS SOUTHWESTWARD THROUGH THE
CAROLINAS. THIS WILL MAINTAIN NE WINDS AT A HEFTY 15-20 KT THROUGH
THE PERIOD. WITH SUCH A LARGE PORTION OF THE WESTERN ATLANTIC
AFFECTED BY THESE WINDS LOOK FOR SEAS TO INCREASE TO 7-8 FEET AT
10-20 MILE DISTANCES FROM SHORE NEAR CAPE FEAR AND EAST OF WINYAH
BAY. DOMINANT WAVE PERIODS SHOULD INCREASE TO 8-10 SECONDS.
CONDITIONS WILL BE EVEN ROUGHER OUT NEAR THE GULF STREAM WHERE
CONSIDERABLE SHOWER ACTIVITY MAY ALSO OCCUR ESPECIALLY THURSDAY
AND THURSDAY NIGHT.
LONG TERM /SATURDAY THROUGH MONDAY/...
AS OF 300 PM WEDNESDAY...NORTHEAST FLOW WILL CONTINUE THROUGH THE
PERIOD WITH HIGH PRESSURE BUILDING DOWN THE COAST. GRADIENT FOR MUCH
OF THE PERIOD WILL MAINTAIN SPEEDS IN THE 15 TO 20 KT RANGE.
EXTENDED PERIOD OF NORTHEAST FLOW AT OR ABOVE 15 KT WILL KEEP SEAS
ACROSS THE WATERS ELEVATED...ESPECIALLY IN THOSE AREAS EXPOSED TO
NORTHEAST FLOW. SEAS WILL RANGE FROM 3 FT NEAR SHORE TO AS HIGH AS 7
FT NEAR FRYING PAN SHOALS. HEADLINES WILL LIKELY BE NEEDED FOR AT
LEAST THE FIRST HALF OF THE PERIOD.
&&
.TIDES/COASTAL FLOODING...
AS OF 300 PM WEDNESDAY...HIGHER OF TWO DIURNAL CYCLES HAS BEEN
AND WILL CONTINUE TO BE MORNING TIDES. THE RIVERFRONT AT
WILMINGTON HAS BEEN REACHING ADVISORY LEVELS AT BOTH TIDES AS OF
LATE, EVEN THE LOWER EVENING HIGH TIDE. THE FORECAST (WHICH HAS
ERRED SLIGHTLY HIGH) NOW SHOWS A PEAK OF ABOUT 5.4 FT WHICH IS
JUST SHY OF ADVISORY LEVEL OF 5.5 FT MLLW.
TIDES MAY APPROACH MINOR FLOOD LEVELS AT THE BEACHES WITH THURSDAY`S
7 AM HIGH TIDE. ONLY A 0.5 TO 0.7 FOOT ANOMALY WILL BE ENOUGH TO
REACH THE 6.0 FT MLLW FLOOD LEVEL AT WRIGHTSVILLE BEACH AND 7.5 FT
MLLW AT MYRTLE BEACH. THIS APPEARS POSSIBLE GIVEN SUSTAINED
NORTHEAST WINDS EXPECTED OVERNIGHT INTO THURSDAY MORNING.
&&
.ILM WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
NC...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 6 AM EST SATURDAY FOR AMZ250-252-
254-256.
&&
$$
SYNOPSIS...TRA
NEAR TERM...MBB
SHORT TERM...TRA
LONG TERM...III
AVIATION...DL
TIDES/COASTAL FLOODING...MBB/TRA
AREA FORECAST DISCUSSION
NWS HOUSTON/GALVESTON TX
230 PM CST WED NOV 25 2015
.DISCUSSION...
PRONOUNCED MID/UPPER LOW OVER THE SIERRA MOUNTAIN REGION WILL
CONTINUE TO DIG SWD INTO THE SRN GREAT BASIN WHERE IT WILL REMAIN
THROUGH THE WEEKEND. THIS WILL MAINTAIN BROAD SWLY FLOW ALOFT
ACROSS THE SRN PLAINS AND SUPPLY AMPLE MOISTURE. IN
ADDITION...HURRICANE SANDRA OVER THE ERN PAC WILL CONTINUE TO
CHURN NEWD AND MAKE LANDFALL AS A TS OVER MAINLAND MEXICO EARLY
SUNDAY MORNING...WITH BROAD FEED OF ASSOCIATED TROPICAL MOISTURE
SPREADING INTO TX THROUGH THE WEEKEND. LOW LEVEL GULF MOISTURE
RETURN IS WELL UNDERWAY ACROSS THE LOWER AND MIDDLE TX COAST THIS
AFTERNOON WHICH WILL OVERSPREAD THE REST OF THE UPPER TX COAST
OVER THE NEXT FEW DAYS. THE NET RESULT WILL BE MILD AND UNSETTLED
WEATHER OVER SERN TX INTO THE WEEKEND.
AS MOISTURE RETURN OVERSPREADS THE AREA WE CAN EXPECT A GENERAL
INCREASE IN RAIN CHANCES...MOSTLY AS SCATTERED SHOWERS THURSDAY
AND FRIDAY INCREASING TO STEADIER RAIN IN THE NORTHERN COUNTIES
FRIDAY AND SATURDAY. WILL KEEP CHANCE POPS OVER THE WRN COUNTIES
BEGINNING TOMORROW MORNING WHERE HRRR SPREADS SOME LIGHT SHOWERS
OUT OF CENTRAL TX. HOWEVER...FOR ALL BUT THE IMMEDIATE COAST AND
SERN COUNTIES...PRIMARY RAIN CHANCES BEGIN FRIDAY MORNING AND
CONTINUE INTO SUNDAY. WHILE THE HEAVIEST RAIN WILL LIKELY OCCUR TO
THE NORTH AND WEST OF SOUTHEAST TX...SOME AREAS NORTH OF A
COLUMBUS-CONROE-LIVINGSTON LINE COULD STILL SEE RAIN TOTALS FROM
1-2" BETWEEN FRI AND SUN. MUCH OF THE HOUSTON METRO INTO THE COAST
ARE EXPECTED TO SEE LESSER AMOUNTS.
TEMPERATURES WILL BE QUITE WARM FOR THIS LATE IN NOV WITH
AFTERNOON HIGHS APPROACHING 80F FOR A FEW SPOTS THURSDAY AND
FRIDAY...PRIOR TO THE COLD FRONT SAGGING ACROSS THE AREA SATURDAY.
BEHIND THE FRONT WE WILL LIKELY CUT TEMPS 20 DEGREES FOR HIGHS BY
SUNDAY. WE LOOK TO REMAIN BELOW NORMAL THROUGH NEXT WEEK...WITH
UNSETTLED WEATHER CONTINUING AS MOIST WLY FLOW ALOFT REMAINS IN
PLACE.
48
&&
.MARINE...
FOR TONIGHT...WILL CONTINUE TO CARRY CAUTION FLAGS FOR THE OFFSHORE
WATERS DUE TO THE ELEVATED WINDS AND HIGHER SEAS. NEARSHORE WATER
FORECAST WILL CARRY WINDS AROUND 15 KNOTS...BUT ADD ANOTHER KNOTS OR
TWO AND CAUTION FLAGS WILL BE NEEDED THERE TOO. SLIGHT INCREASE IN
BOTH WINDS AND SEAS IS STILL ANTICIPATED TOMORROW AND FRIDAY.
ADVISORIES WILL LIKELY BE NEEDED OFFSHORE...AND CAUTION FLAGS ARE
EXPECTED FOR THE NEARSHORE WATERS AND MAYBE THE BAYS TOO. EXPECT
GRADUALLY LOWERING WINDS AND SEAS OVER THE WEEKEND WITH THE APPROACH
AND PASSAGE OF A COLD FRONT. THIS FRONT IS CURRENTLY EXPECTED TO MOVE
INTO THE WATERS LATE SATURDAY NIGHT OR EARLY SUNDAY MORNING AND
THROUGH THE AREA DURING THE DAY ON SUNDAY. AT THIS TIME...NO FLAGS
ARE ANTICIPATED BEHIND THIS FRONT DUE TO THE LOW ENOUGH WIND AND SEA
FORECAST. WILL CONTINUE TO MONITOR FOR POSSIBLE SEA FOG FORMATION
OVER THE NEXT COUPLE OF DAYS. ALSO...ELEVATED TIDES AND EXPECTED TO
PERSIST.
42
&&
.PRELIMINARY POINT TEMPS/POPS...
COLLEGE STATION (CLL) 65 76 67 75 54 / 20 40 30 70 60
HOUSTON (IAH) 66 77 70 77 62 / 20 20 30 50 40
GALVESTON (GLS) 68 75 69 75 67 / 20 20 20 30 30
&&
.HGX WATCHES/WARNINGS/ADVISORIES...
TX...NONE.
GM...SMALL CRAFT SHOULD EXERCISE CAUTION UNTIL 3 PM CST THIS
AFTERNOON FOR THE FOLLOWING ZONES: WATERS FROM FREEPORT TO
THE MATAGORDA SHIP CHANNEL OUT 20 NM...WATERS FROM HIGH
ISLAND TO FREEPORT OUT 20 NM.
SMALL CRAFT SHOULD EXERCISE CAUTION THROUGH LATE THURSDAY NIGHT
FOR THE FOLLOWING ZONES: WATERS FROM FREEPORT TO THE
MATAGORDA SHIP CHANNEL 20 NM TO 60 NM...WATERS FROM HIGH
ISLAND TO FREEPORT 20 TO 60 NM.
&&
$$
DISCUSSION...48
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
326 PM CST WED NOV 25 2015
.SHORT TERM...(THIS EVENING THROUGH THURSDAY)
ISSUED AT 325 PM CST WED NOV 25 2015
CURRENTLY AS OF 21Z...WATER VAPOR LOOP AND RAP 500MB HEIGHT ANALYSIS
SHOWED DEEP TROUGHING OVER THE WESTERN U.S. WITH A CLOSED LOW OVER
NEVADA...TROUGHING OVER SOUTH CENTRAL CANADA...AND BROAD RIDGING
FROM TEXAS INTO NEW ENGLAND. REAL ONLY SHORTWAVE OF NOTE WAS IN
NORTHWEST KS. SOUTHERLY LOW LEVEL FLOW UNDERNEATH THE BROAD RIDGING
HELPING TO PROPEL WARMER...MORE MOIST AIR NORTHWARD. 925MB TEMP AT
MPX JUMPED FROM 2C AT 00Z TO 6C AT 12Z. 50F DEWPOINTS WERE
APPROACHING THE IA/MO BORDER...AHEAD OF A COLD FRONT LAYED UP FROM
DLH TO LINCOLN NE. PLENTY OF CLOUDS OVERHEAD WHICH HAS KEPT TEMPS
BACK SOMEWHAT...BUT STILL WARM AND MOIST ADVECTION ALONE HAS PUSHED
READINGS WELL INTO THE 40S AND EVEN A FEW 50S FOR LOCATIONS THAT SAW
SOME PEAKS OF SUN. THE RECENT WARMTH HAS REALLY DENTED THE SNOWPACK
TOO...WITH DEPTHS MOSTLY UNDER 5 INCHES PER 12Z COOP REPORTS...WHICH
HAS GREATLY REDUCED ITS IMPACT ON TEMPERATURES. DESPITE THE
CLOUDS...NO PRECIPITATION HAS OCCURRED YET...AS THE CLOUD LAYER
REMAINS SOMEWHAT SHALLOW AND RELATIVELY SPEAKING HIGH BASED / ALL
EITHER HIGH MVFR OR VFR IN AVIATION TERMS/.
MAIN FOCUS TONIGHT IS ON THE UPPER TROUGH OVER SOUTH CENTRAL CANADA.
AS THIS TROUGH PUSHES SLIGHTLY EAST...WE SEE THE FRONT OFF TO OUR
WEST MOVE ALMOST ALL THE WAY THROUGH THE FORECAST AREA BY 12Z THU.
THE NOCTURNAL INCREASE IN THE LOW LEVEL JET SHOULD HELP TO KEEP
PUSHING WARM/MOIST AIR INTO US...NOTED IN PRECIPITABLE WATER
CLIMBING FROM 0.5-0.75 INCHES AT 18Z TODAY TO 0.75-1 INCH AT 12Z
THU. READINGS WILL LIKELY CLIMB THROUGH THE EARLY OVERNIGHT
TOO...BEFORE FALLING WITH THE FRONTAL PASSAGE. THUS ANTICIPATING
THANKSGIVING DAY CALENDAR HIGH TO OCCUR TONIGHT. THE INCREASE IN
MOISTURE ALSO OCCURS FROM NEAR THE SURFACE TO 6000 FT...WITH WEAK
ISENTROPIC LIFT TAKING PLACE IN THIS LAYER. THEREFORE WE SHOULD SEE
DRIZZLE. IN FACT...LOW LEVEL FRONTOGENESIS INCREASES AFTER MIDNIGHT
IMMEDIATELY IN THE WAKE OF THE FRONTAL PASSAGE...SO SHOULD SEE FLAT
OUT HIGHER QPF / LIGHT RAIN TAKE PLACE. THIS IS ABOUT THE SAME TIME
THAT THE SHORTWAVE IN NORTHWEST KANSAS LIFTS ACROSS THE AREA. BOTH
THE DRIZZLE AND INCREASE IN PRECIPITATION INTENSITY IS EVIDENT IN
ALL MODEL QPF PROGS...WITH VERY LITTLE DIFFERENCE. NOT EXPECTING ANY
PRECIPITATION TYPE CONCERNS TONIGHT...GIVEN TEMPERATURES STAYING
ABOVE FREEZING AND PLENTY OF MID LEVEL DRY AIR ABOVE THE LOWER
CLOUDS TO PRECLUDE ANY SEEDER-FEEDER TO INTRODUCE SNOW CRYSTALS.
THE FORECAST FOR THANKSGIVING DAY GETS MORE INTERESTING. THE TWO
UPPER TROUGHS OFF TO OUR WEST ATTEMPT TO PHASE...WHICH IN TURN
INTENSIFIES THE BAROCLINIC ZONE AROUND THE FRONT THAT MOSTLY PASSED
THROUGH OVERNIGHT...INTENSIFIES THE UPPER JET AND THROUGH THERMAL
WIND RELATIONSHIP...INTENSIFIES THE LOW TO MID LEVEL
FRONTOGENESIS. WITH PRECIPITABLE WATER PROGGED TO HOLD STEADY OR
EVEN INCREASE SLIGHTLY IN OUR SOUTHEAST...THE NET RESULT IS FOR
PRECIPITATION TO INTENSIFY THROUGH THE DAY. THE HEAVIEST
PRECIPITATION...LUCKILY IN THE FORM OF RAIN BUT DEFINITELY NOT
ENOUGH TO CAUSE HYDRO CONCERNS...LOOKS TO FALL IN CLAYTON/GRANT
COUNTIES WHERE THE BEST JUXTAPOSITION EXISTS OF STRONGEST AND
DEEPEST FRONTOGENESIS AND RIGHT ENTRANCE REGION DYNAMICS. WOULD
NOT BE SURPRISED TO EVEN SEE SOME LIGHTNING NEAR DUBUQUE WITH UP
TO 100 J/KG OF MUCAPE PROGGED. FARTHER BACK TO THE NORTHWEST...LOW
LEVEL COLD ADVECTION COMBINED WITH DEEPER SATURATION FROM THE
SURFACE TO THE TROPOPAUSE TO PREVENT LOSS OF SNOW/ICE
CRYSTALS...SHOULD HELP GRADUALLY TURN PRECIPITATION INTO SLEET
THEN SNOW. THIS IS ESPECIALLY TRUE FROM MCW TO RST AND EAU. SINCE
THE FORCING IS WEAKER COMPARED TO CLAYTON/GRANT
COUNTIES...PRECIPITATION IS LIGHTER...BUT STILL LIKELY ENOUGH TO
CAUSE TRAVELING ISSUES. THUS...HAVE ISSUED A WINTER WEATHER
ADVISORY FOR THE NORTHWEST PORTION OF THE FORECAST AREA.
.LONG TERM...(THURSDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 325 PM CST WED NOV 25 2015
ON THURSDAY NIGHT THE UPPER TROUGH OVER SOUTH CENTRAL CANADA FINALLY
BEGINS TO MAKE SOME BETTER PROGRESS EASTWARD. THIS WILL HELP TO PUSH
ALL OF THE FORCING...PRECIPITATION AND MOISTURE THAT WAS OVER OUR
REGION THURSDAY AFTERNOON TO THE EAST. APPEARS IT MAY TAKE UNTIL THE
LATE OVERNIGHT HOURS FOR THE PRECIPITATION TO FULLY EXIT OUR AREA.
UNTIL THEN...HOWEVER...PERSISTENT LOW LEVEL COLD ADVECTION NOTED BY
925MB TEMPS FALLING FROM -5C TO 5C AT 00Z FRI TO -8 TO -5C BY 12Z
FRI...COMBINED WITH A DRY SLOT PUNCHING IN SHOULD HELP TRANSITION
PRECIPITATION OVER TO A WINTRY MIX OF SLEET...SNOW AND
DRIZZLE/FREEZING DRIZZLE BEFORE ENDING. NOW...IT IS POSSIBLE THAT
WHEN THE DRY SLOT PUNCHES IN...THE PRECIPITATION ENDS AS WELL AS
NOTED IN THE CURRENT AND PAST RUNS OF THE GFS. APPEARS ANY SNOW OR
FREEZING DRIZZLE ACCUMULATION WILL BE LIGHT...BUT STILL ENOUGH OF AN
IMPACT TO WARRANT THE WINTER WEATHER ADVISORY FOR OUR NORTHWEST.
SNOW/FREEZING DRIZZLE AMOUNT FOR THE SOUTHEAST HALF APPEARS TOO
LITTLE TO WARRANT AN ADVISORY.
WEATHER GOES INTO QUIET AND SEASONABLY COOL LAND FOR FRIDAY INTO THE
WEEKEND AS HIGH PRESSURE MOVES IN AT THE SURFACE...AND THE AREA GOES
UNDER A WEST TO NORTHWEST FLOW ALOFT BY LATE SATURDAY. 925MB TEMPS
HOLD BETWEEN -5 AND -8C FOR FRIDAY INTO SAT MORNING BEFORE WARMING
TO 0 TO -2C SAT AFTERNOON THROUGH SUNDAY. THESE READINGS SUPPORT
HIGHS MAINLY IN THE 30S...THOUGH SOME LOCATIONS WEST OF THE MS RIVER
COULD STAY JUST BELOW 30 ON FRIDAY.
MUCH OF NEXT WEEK PER THE ECMWF/GFS/CANADIAN LOOKS LIKE WE WILL BE
DOMINATED BY THE CURRENT UPPER LOW OVER NEVADA WHICH GRADUALLY MAKES
ITS WAY EASTWARD INTO THE AREA. AHEAD OF THE UPPER LOW COULD SEE
SOME PRECIPITATION MON THROUGH TUESDAY...BUT THEN THE MOISTURE
GETS SHUNTED EASTWARD SUCH THAT ONCE THE UPPER LOW MOVES OVERHEAD
FOR WEDNESDAY...THE PRECIPITATION ENDS. CERTAINLY SOME TIMING AND
OTHER SYNOPTIC DIFFERENCES THUS PRECIPITATION CHANCES ARE ONLY IN
THE 20- 40 RANGE AT THIS TIME. COOL AIR UNDERNEATH THE UPPER LOW
COMBINED WITH PRECIPITATION EXPECTED TO KEEP TEMPERATURES NEAR OR
SLIGHTLY BELOW NORMAL...WHICH RESULTS IN SNOW AS THE MAIN
PRECIPITATION TYPE. DEFINITELY TOO MUCH UNCERTAINTY TO LOOK AT
ACCUMULATIONS AT THIS POINT.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z THURSDAY AFTERNOON)
ISSUED AT 1146 AM CST WED NOV 25 2015
WITH THE TREND IN THE MODELS SHOWING THAT THE LIFT AND MOISTURE
WILL ARRIVE LATER...DELAYED THE LOWERING OF BOTH THE CEILINGS AND
VISIBILITIES BY 3 TO 6 HOURS AT THE TAF SITES. THIS ALSO IMPACTED
THE ONSET OF THE RAIN IN THE AREA. SOUNDINGS CONTINUE TO SHOW THAT
THE PRECIPITATION WILL REMAIN RAIN AT THE TAF SITES THROUGH
26.18Z...AND THEN GRADUALLY TRANSITION TO A WINTRY MIX BETWEEN
26.18Z AND 27.00Z.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...WINTER WEATHER ADVISORY FROM NOON THURSDAY TO MIDNIGHT CST
THURSDAY NIGHT FOR WIZ017-029-033-034.
WINTER WEATHER ADVISORY FROM 9 AM THURSDAY TO MIDNIGHT CST
THURSDAY NIGHT FOR WIZ032.
MN...WINTER WEATHER ADVISORY FROM NOON THURSDAY TO MIDNIGHT CST
THURSDAY NIGHT FOR MNZ088-095.
WINTER WEATHER ADVISORY FROM 9 AM THURSDAY TO MIDNIGHT CST
THURSDAY NIGHT FOR MNZ079-086-087-094.
IA...WINTER WEATHER ADVISORY FROM NOON THURSDAY TO MIDNIGHT CST
THURSDAY NIGHT FOR IAZ009-018-019.
WINTER WEATHER ADVISORY FROM 9 AM THURSDAY TO MIDNIGHT CST
THURSDAY NIGHT FOR IAZ008.
&&
$$
SHORT TERM...AJ
LONG TERM...AJ
AVIATION...BOYNE