Forecast Discussions mentioning any of
"HRRR" "RAP" "RR" "RUC13" "RUC" received at GSD on 01/20/13
AREA FORECAST DISCUSSION
NWS LOUISVILLE KY
635 PM EST SAT JAN 19 2013
...Updated Aviation Discussion...
.Short Term (Tonight - Sunday Night)...
Issued at 250 PM EST Sat Jan 19 2013
The synoptic pattern this afternoon features a sharp ridge just off
the Pacific Coast, with an expansive, broad trough encompassing much
of the central and eastern United States. The first in a series of
shortwaves will drop through this trough in northwest flow aloft
tonight, beginning the downward spiral in temperatures over the next
few days.
Conditions have remained rather breezy this afternoon, which has
helped temperatures warm well into the 50s, with some locations
across south central Kentucky even flirting with 60 degrees.
However, the aforementioned shortwave will quickly dive southeast
overnight, spreading a surface cold front southeast through the
state early Sunday morning. After 850 temps around +5C today, they
will fall to about -4C to -2C tomorrow. Therefore, highs on Sunday
will fall into the upper 30s (southern Indiana) and middle 40s
(south central Kentucky).
A strong 1040mb Canadian high will nose into the Central Plains on
Sunday night. With a heightened pressure gradient due to the
strength of the high, northwesterly surface winds should stay up
enough to offset radiative cooling somewhat. However, continued
cold air advection through the night will be enough to drop
temperatures into the low to mid 20s by early Monday morning.
.Long Term (Monday through Saturday)...
Issued at 335 PM EST Sat Jan 19 2013
Monday through Wednesday Night...
Latest model guidance continues to be in pretty good agreement
during this portion of the forecast period. First shot of Arctic
air will push into the region during the day on Monday. As this
occurs, a small embedded mid-level wave will streak through the
trough axis during the day. While model proximity soundings from
across the forecast area still relatively dry, enough moisture looks
to be available for at least scattered snow flurries across much of
the region. Deeper moisture and better forcing will be located to
our north which would be more supportive of snow showers. As the
wave shifts eastward, some left over snow flurries will be possible
Monday night in the east. Highs Monday will be quite cold with
readings struggling to warm into the low-mid 20s across southern
Indiana and northern KY...while upper 20s will be possible across
southern KY. Much colder air is very likely for Monday night and
Tuesday morning. Latest guidance still suggests upper single digits
north of the river, with lower teens across much of Kentucky. Main
question regarding temperatures will be the pressure gradient and
how much wind we have. If winds end up being lighter, colder
temperatures are likely. We are not expecting much of a warm up on
Tuesday as strong cold air advection continues. Highs will only
warm into the mid-upper teens in Indiana and the northern half of
Kentucky with upper teens to the lower 20s across southern Kentucky.
By Tuesday night and into Wednesday, there is an stronger signal
in the data that another mid-level wave will streak through the area
within the fast cold flow aloft. Generally speaking, it`s a clipper
type system that will bring snow flurries or perhaps a swath of
light snow to southern Indiana and portions of north/east-central
Kentucky. Model QPF and ensemble probabilistic forecasts are still
quite low and there continues to be a good spread in the ensemble
QPF guidance. For now, will go ahead and place snow flurries into
the forecast. However, if the mid-level wave ends up being stronger
than forecast, then light snow will likely be needed for that
portion of the forecast. The mid-level feature should be well to
our east by Wednesday night leaving the area dry. Lows Tuesday
night will generally be in the 10-15 degree range across southern
Indiana and northern Kentucky. 15-20 degree readings look likely
across the south. Highs on Wednesday will moderate slightly, but
not as much as the models suggest. Thus, have undercut guidance
here and went with upper 20s in the north and lower-mid 30s across
the south. Lows Wednesday night do not look as cold as the previous
nights, with lows in the upper teens to around 20 in the north with
lower 20s in the south.
Thursday through Saturday...
...Period of Wintry Weather Increasingly Likely Thursday-Friday
Along With Continued Cold Weather...
This morning`s model guidance suite has shown some forecast
convergence in the Thursday-Friday time frame. For the last several
days, the long term guidance has been strongly advocating for a
quick moderation in temperatures beyond mid-week. However, the
latest trends in the data are quickly backing off of that idea.
Historically, synoptic scale models have always had a bias in being
too progressive aloft and near the surface in moderating
temperatures on the heels of an arctic outbreak. Given the coarser
vertical resolution in these models, they typically do not capture
low-level cold air all that well...and I think they are starting to
catch on to this. By Thursday, the large scale guidance shows
another trough that will be dropping into the eastern US and
re-enforcing the cold air. As this trough gets carved out, there is
a separate wave that will be approaching from within the southern
stream on the southern periphery of the antecedent Arctic airmass.
The operational GFS and Canadian GEM both overpower the northern
stream (known model biases) and allows a surface low to cut from the
Ozarks northeastward into the Great Lakes. On the other hand, the
last few runs of the GFS ensemble and the latest 19/12Z Euro keep
the systems more separate and weaker which results in the system
passing to our south. Given the model biases here of warming things
up too quickly and overpowering the northern jet, we are not going
to use the operational GFS and Canadian for this forecast. Instead
we will be trending the forecast much closer to the GFS Ensemble and
Euro blend.
With those ideas in mind, the more southerly solution of the GFS
Ensemble and operational Euro opens the possibility of a wintery
weather event in the Thursday afternoon through Friday time frame.
Depending on the evolution of the thermal structure, snow looks
likely across southern Indiana and much of northern Kentucky. The
question mark resides across our south where some low-level warm air
may creep over the top of the existing Arctic airmass and result in
mixed precipitation issues. Given our preference on the colder
solutions, will go ahead and go with light snow across southern
Indiana and northern Kentucky, while keeping a wintry mix across the
south. This system will need to be watched over the next couple of
days. So stay tuned for the latest forecasts. Cold and wintry
conditions are expected to linger into Saturday as the upper trough
remains in control across the eastern US.
As for temperatures, going with the colder ensemble/Euro solutions
requires a downward adjustment in temperatures. For Thursday we
should see highs in the upper 20s-lower 30s across our north with
mid-upper 30s in the south. Friday and Saturday will see highs
likely in the upper 20s to the lower 30s with overnight lows in
teens to lower 20s.
&&
.Aviation (00Z TAF Issuance)...
Issued at 630 PM EST Sat Jan 19 2013
A dry cold front over the Midwest will sweep across the Ohio Valley
Sunday morning, bringing in much cooler air. Model time height
sections indicate a couple of issues with this front. First will be
some stronger winds just above the surface, as the boundary layer
collapses and an inversion sets up. Thus will keep in low level wind
shear for the first several hours. That shear will relax before
daybreak as the area of stronger winds aloft heads east. Then those
cross sections indicate low-level moisture able to develop some
lower clouds toward daybreak. Latest RAP has these clouds with LIFR
cigs starting near KLEX at 11Z. Guidance does not pick up on these
clouds, but given that the local WRF, NAM, and GFS all indicate some
moisture in the low levels, have put in few to scattered lower
clouds with this package around daybreak. We may have to bump up
coverage as the night goes on. Otherwise, the front will bring a
wind shift, to northwesterly, will occur as it swings through the
terminals in the morning.
&&
.LMK WATCHES/WARNINGS/ADVISORIES...
IN...NONE.
KY...NONE.
$$
Short Term.......KJD
Long Term........MJ
Aviation.........RJS
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
107 PM EST FRI JAN 18 2013
.UPDATE...
ISSUED AT 1023 AM EST FRI JAN 18 2013
WARM AIR ADVECTION EVIDENT UPSTREAM ON SOUTHERN FRINGE OF UPPER
TROUGH OVER HUDSON BAY/NORTHERN QUEBEC. WARM AIR ADVECTION AND H8-H6
FRONTOGENESIS IN ENTRANCE REGION OF JET STREAK OVER ONTARIO AFFECTS
THE AREA WITH WIDESPREAD SNOW TODAY. H8-H7 FRONTOGENESIS EXPECTED TO
EXPAND EAST ACROSS SOUTHERN TIER THIS MORNING AND ACROSS LK MICHIGAN
ZONES THIS AFTN AND INTO EVENING. 12Z NAM IS CONSISTENT WITH 06Z RUN
AND MATCHES WELL WITH RUC/LOCAL-WRF AND MOST IMPORTANTLY REALITY
BASED ON RADAR/SFC OBS. EXPECT INCREASING SNOW OVER SCNTRL AND
SOUTHEAST CWA THROUGH AFTN...CUTTING OUT FIRST ALONG WI BORDER.
BASED ON LOCAL WRF AND RUC QPF AMOUNTS ALONG WITH EXPECTED SNOW
RATIOS SOMEWHERE IN 10-17:1 RANGE...EXPECT ADVY SNOW AMOUNTS UP TO 5
INCHES OVR PORTIONS OF SCNTRL AND SOUTHEAST/EAST ZONES FOR THIS
EVENT. SOUTHWEST FLOW OFF LK MICHIGAN WITH TEMPS AT INVERSION TOP
AROUND -10C LEADING TO SUFFICIENT OVER-WATER INSTABILITY ALSO COULD
RESULT IN ADDITIONAL INCH OR TWO DUE TO LAKE ENHANCEMENT.
SO...COORD WITH APX AND ISSUED WINTER WEATHER ADVY INTO THE EVENING
FOR DELTA THROUGH LUCE COUNTIES. FARTHER WEST...THERE IS POTENTIAL
FOR ENHANCED BAND OF SNOW TO PUSH TOTALS PAST 3 INCHES...BUT SINCE
HEAVIER SNOW FROM GOGEBIC THROUGH MENOMINEE ONLY LASTS INTO MID AFTN
AND WILL BE PRETTY LOCALIZED...PLAN NOT ISSUE ADVY THERE AND CONTINUE
TO ADDRESS VIA SPECIAL WEATHER STATEMENTS. THAT COULD CHANGE BASED ON
REPORTS THOUGH. BASED ON SOUNDINGS WHEN SNOW CUTS OUT THIS AFTN...SHOULD
SEE TRANSITION TO LGT SNOW AND/OR FREEZING DRIZZLE.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 435 AM EST FRI JAN 18 2013
SATELLITE AND RADAR ARE SHOWING THE LAKE EFFECT STILL ONGOING
OVER THE KEWEENAW AND FOR LOCATIONS EAST OF MUNISING. WITH WINDS
CONTINUING TO BACK TO THE WEST AND THEN SOUTHWEST EARLY THIS
MORNING...EXPECT THE LAKE EFFECT TO FOLLOW SUIT AND DEPART THE
EASTERN CWA THIS MORNING. WITH THE INTENSITY OF THE SNOW
DIMINISHING AND A STEADY MOVEMENT EASTWARD...WILL LET THE
ADVISORY EXPIRE AT 12Z. ELSEWHERE...THE HIGH PRESSURE RIDGE OVER
THE CWA AT THIS TIME HAS LED TO A PERIOD OF CLEAR SKIES OVER THE
CENTRAL CWA FOR A PERIOD THIS MORNING...ALLOWING SOME LOCATIONS TO
DROP INTO THE SINGLE DIGITS BELOW ZERO. MID AND HIGH CLOUDS HAVE
STOPPED THE TEMP DROP ALONG THE WISCONSIN BORDER AS THEY MOVE OVER
THE CWA AHEAD OF THE MAIN WEATHER MAKER FOR TODAY.
THE AREA OF LOW PRESSURE IS CURRENTLY IN SOUTHERN
SASKATCHEWAN...BUT AN SURFACE TROUGH STRETCHING SOUTHEAST THROUGH
THE DAKOTAS AND ASSOCIATED H850 TROUGH TO THE NORTHEAST OF THAT HAS
LED TO LIGHT SNOW UNDER THE BROAD WARM AIR ADVECTION THIS MORNING
IN MN AND WESTERN WI. THE LOW IS EXPECTED TO DROP SOUTHEAST THROUGH
NORTHERN MN TODAY AND INTO NORTHERN WISCONSIN OR SOUTHERN UPPER
MICHIGAN BY 00Z SATURDAY. WITH THE RIGHT REAR OF THE UPPER JET
MOVING OVER UPPER MICHIGAN AND THE SHORTWAVE MOVING THROUGH THIS
AFTERNOON AND EARLY EVENING...EXPECT THE LOW TO INTENSIFY SOME. THE
MAIN FOCUS FOR THE SNOW WILL BE THE STRONG H850-700 AND H700-500
WARM AIR ADVECTION AND ASSOCIATED FGEN ON THE H850-600 LAYER. THE
H700-500 WAA MOVES DIRECTLY ACROSS THE CWA AND THAT WILL LEAD THE
BROAD INITIAL SNOW...WHILE THE LOCATION OF THE H850-700 WAA WILL BE
THE DETERMINING FACTOR FOR THE HEAVIER QPF/SNOW. LATEST RUNS SHOW
THIS TO BE FOCUSED OVER THE SOUTHERN HALF OF UPPER MI...BUT IT
SHOULD AFFECT MUCH OF THE CWA TODAY BEFORE QUICKLY EXITING TONIGHT.
DEFINITELY A SHIFT TO THE SOUTH BY ABOUT 10-30 MILES WITH THE AXIS
OF BEST QPF...WITH MOST MODELS NOW SHOWING IT RUNNING ALONG THE WI
BORDER THIS MORNING AND THEN FOCUSING FARTHER NORTHEAST INTO
EASTERN UPPER MICHIGAN AS A SURFACE TROUGH SHARPENS AND ADDITIONAL
MOISTENING OCCURS OFF LAKE MICHIGAN WITH THE WINDS TURNING
SOUTHERLY. THUS...HAVE SHIFTED THE GOING FORECAST SLIGHTLY TOWARDS
THIS LATEST IDEA. SOME OF THE RECENT RAP/HRRR RUNS VARY BACK
AN FORTH ON THAT MORE SOUTHERN IDEA...WHILE THE 00Z ECMWF STILL
KEEPS A MORE NORTHERN SOLUTION. THIS DOES LEAD TO SOME UNCERTAINTY
ON THE NORTHERN SNOWFALL AMOUNTS. THESE TWEAKS ALSO ADJUSTED THE
TIMING SOME WHAT...WITH IT MOVING INTO THE SOUTHWESTERN CWA
AROUND 12Z AND THEN QUICKLY SHIFTING FROM WEST TO EAST AND MUCH OF
THE CWA SEEING SNOW THIS MORNING OR SHORTLY AFTER NOON IN THE
EAST.
WITH THE INITIAL PRECIPITATION OCCURRING WITHOUT TOO MUCH OF THE
LOWER LEVELS BEING SATURATED...THINKING THAT INITIAL SNOW RATIOS
WILL BE IN THE 20-24 TO 1 RANGE. THEN AS THE LOW LEVELS BECOME
SATURATED AND WAA FORCING BECOMES LOCATED BELOW THE DGZ...THERE WILL
BE A QUICK TRANSITION DOWN THROUGH THE TEENS TO A 13 TO 1 SNOW
RATIO. THIS TRANSITION AND IT/S TIMING MAKES FOR A DIFFICULT SNOW
FALL FORECAST...WHICH WILL LIKELY BE RIGHT NEAR ADVISORY LEVELS OVER
EASTERN DELTA...SCHOOLCRAFT...AND SOUTHERN LUCE COUNTIES AS IT MOVES
THROUGH THIS AFTERNOON AND EARLY EVENING. WITH THE ADDITIONAL
MOISTENING AND FORCING FOR THAT AREA BEING ROOTED BELOW THE
DGZ...WONDERING IF THAT WILL BE ENOUGH TO KEEP AMOUNTS AT OR JUST
BELOW THE 3INCH IN 12HR CRITERIA FOR SNOW RATIOS BELOW 20-1. EVEN
WITH THIS SLIGHT SOUTHWARD SHIFT...STILL EXPECT MOST LOCATIONS TO
SEE AN INCH OF SNOW...WITH THE HIGHEST AMOUNTS OVER THE SOUTHERN
U.P. /AROUND 2-2.5 INCHES/ AND OVER THE EAST WHERE LAKE ENHANCEMENT
WILL PUSH VALUES UP TO OR JUST ABOVE 3 INCHES. DUE TO THE
UNCERTAINTY WITH THE NORTHWARD EXTENT ON THE HEAVIEST SNOW AND
CURRENT BORDERLINE ADVISORY AMOUNTS...WILL NOT ISSUE AN ADVISORY AT
THIS POINT BUT KEEP THE MENTION IN THE HWO.
BEHIND THE MAIN WAA PRECIPITATION TODAY...DEEPER MOISTURE REMAINS
OVER THE NORTHERN HALF OF THE CWA TONIGHT AND EXPECT SCATTERED SNOW
SHOWERS THERE AS A SECONDARY WEAK SHORTWAVE MOVES ACROSS LAKE
SUPERIOR. THE KEWEENAW PENINSULA WOULD SEE THE BEST CHANCE FOR
ACCUMULATION...BUT OVERALL AMOUNTS WILL BE LIGHT. SUBSIDENCE WILL BE
ON THE INCREASE OVERNIGHT BEHIND THE SHORTWAVE AND SHOULD BRING AN
END TO THE SNOWFALL. ELSEWHERE...LOW LEVEL MOISTURE WILL BE STUCK
BELOW THE INVERSION FROM THE WAA AROUND H850 THIS AFTERNOON AND
EVENING BEHIND THE SNOW. THIS WILL LEAD TO CLOUDS AND POTENTIAL
FREEZING DRIZZLE CONDITIONS WITH THE LACK OF ICE CRYSTALS IN THE
CLOUDS. WILL CONTINUE THE GOING IDEA IN THE FORECAST...BUT HAVE
OPTED TO SHOW A DIMINISHING TREND OVERNIGHT OVER ALL BUT THE
KEWEENAW AS THE WINDS BECOME A LESS FAVORABLE WHEN THEY SHIFT TO
THE NORTHWEST.
.LONG TERM...(SATURDAY THROUGH THURSDAY)
ISSUED AT 435 AM EST FRI JAN 18 2013
SAT...NUMERICAL GUIDANCE HAS COME INTO VERY GOOD AGREEMENT SHOWING
VIGOROUS SHRTWV DIGGING SEWD FM NEAR LK WINNIPEG AT 12Z SAT INTO WI
BY LATE IN THE DAY. ASSOCIATED SFC LO IS PROGGED TO MOVE ESEWD OVER
LK SUP TO JUST N-NW OF THE SAULT BY 00Z SUN. THE NAM SHOWS A TRACK A
BIT FARTHER N AND FASTER THAN THE OTHER MODELS...BUT TENDED TOWARD
ITS GUIDANCE PER NCEP PREFERENCE. THE TRACK OF THE SFC-H85 LO/MOST
SGNFT DEEP LYR QVECTOR CNVGC/UPR DVGC TO THE N AND MODEST MSTR
RETURN WL TEND TO LIMIT POPS/SN TOTALS. ANOTHER FACTOR AGAINST A
LARGE SN ACCUM IS FCST THIN DGZ BTWN 10-12K FT. FCST H7 SPECIFIC
HUMIDITY ARND 2 G/KG SUGS AN AVG 1-2 INCH ACCUMULATION FOR A 3-6 HR
PERIOD OF SYNOPTIC SN. BEST CHC FOR THE HIER POPS/SN TOTALS WL BE
OVER THE N AND E CWA. THERE MAY BE LTL ACCUMULATION OVER THE FAR
SCNTRL...ESPECIALLY AT MNM FARTHER FM THE SFC LO TRACK. ALTHOUGH
THERE IS SOME CONCERN THE SW FLOW AHEAD OF THE SFC LO MIGHT BRING
SOME ENHANCEMENT OFF LK MI INTO THE ERN ZNS...LOOKS LIKE THE LLVL
FLOW WL BE SHIFTING TOO STEADILY AND H85 TEMPS MIGHT RISE TOO MUCH
TO OPTIMIZE THE CHC FOR SGNFT ENHANCEMENT OF THE EXPECTED SN TOTALS
IN THIS AREA. SOME PLACES OVER THE E COULD SEE UP TO 3 INCHES.
EXPECT DRYING W-E IN THE AFTN AS LARGER SCALE QVECTOR DVGC/MID LVL
DRYING ARRIVES IN THE WAKE OF THE PASSING LO. SOME LES MIGHT ARRIVE
OVER THE W LATE WITH H85 TEMPS FALLING TOWARD -18 TO -20C BY 00Z SUN.
SAT NGT...WITH INCRSG CYC NW FLOW IN THE WAKE OF DEPARTING SHRTWV/
SFC LO ADVECTING H85 TEMPS UNDER -20C INTO THE CWA...EXPECT LES/BLSN
TO DVLP MAINLY IN THE NW WIND FAVORED SN BELTS. STRONG H925 WINDS
FCST UP TO 35-45 KTS MAY BLOW THE SHSN FARTHER INLAND THAN USUAL.
GIVEN FCST MSTR THRU DEEP CONVECTIVE LYR UNDER FCST INVRN BASE NEAR
8K FT WITHIN SHARP CYC NW FLOW...PERSISTENT LLVL CNVGC IN LONG FETCH
OVER THE LK...AND FCST DGZ UP TO 3K FT...OPTED TO ISSUE A LAKE
EFFECT SN WATCH FOR THE ALGER/LUCE/NRN SCHOOLCRAFT COUNTIES.
ALTHOUGH SOME HEAVIER SHSN MIGHT MOVE INTO THE S HALF OF SCHOOLCRAFT
COUNTY AS WELL LATER AT NGT...DID NOT INCLUDE THAT AREA IN THE WATCH
GIVEN SMALLER WINDOW OF OPPORTUNITY BEFORE WINDS DIMINISH ON
SUN...SEE BLO. ALTHOUGH AN LES/BLSN ADVY WL ALMOST CERTAINLY BE
NECESSARY FOR MUCH OF THE NW CWA...OPTED TO HOLD OFF ON A WATCH ATTM
BECAUSE SHORTER FETCH OVER THE WRN LK IS FCST TO RESULT IN LESS
WARMING...WITH DGZ CONFINED TO ONLY THE NEAR SFC LYR PER FCST SDNGS.
HOWEVER...THE COMBINATION OF SMALLER SN FLAKES/STRONG WINDS/BLSN WL
FAVOR SHARPLY REDUCED VSBYS EVEN IF SN TOTALS ARE LESS THAN OVER THE
SN BELTS E OF MQT. STRENTH OF NW FLOW SHOULD ADVECT LK MODERATION
FAR ENUF INLAND TO MITIGATE THE CHILL OVER EVEN THE FAR SCNTRL AND
PREVENT WIND CHILLS FM FALLING BLO ADVY THRESHOLD.
SUN/SUN NGT...THE GRADIENT NW FLOW IS FCST TO DIMINISH FAIRLY
STEADILY THRU THE DAY ON SUN AS SFC LO IN ERN CAN LIFTS TO THE NE.
LES WL PERSIST IN THE NW WIND SN BELTS THRU THIS TIME...SO WENT WITH
CATEGORICAL POPS IN THESE AREAS. MAINTAINED WATCH FOR ALGER/LUCE/N
HALF OF SCHOOLCRAFT COUNTIES THRU SUN NGT. PASSAGE OF SHRTWV/AREA OF
DEEP LYR QVECTOR DNVGC/DEEP MSTR ON SUN AFTN/EVNG MIGHT BRING SOME
-SHSN/FLURRIES TO EVEN THE SCNTRL. AS THE LLVL FLOW BACKS A BIT MORE
SUN NGT AND ADVECTS MORE UNMODIFIED ARCTIC AIR INTO THAT AREA...WIND
CHILLS MIGHT AT LEAST APRCH ADVY CRITERIA OVER THE SCNTRL.
EXTENDED PERIOD...THE FIRST HALF OF NEXT WEEK WL BE DOMINATED BY
DEEP UPR TROF OVER ERN NAMERICA WITH NW FLOW OVER THE CWA HELD IN
PLACE BY HI LATITUDE BLOCKING...A CLASSIC NEGATIVE NAO PATTERN THAT
FAVORS WELL BLO NORMAL TEMPS OVER THE GRT LKS. EXPECT PERSISTENT NW
FLOW OF ARCTIC AIR WITH H85 TEMPS AS LO AS -25 TO -30C TO BRING
NEARLY CONTINUOUS LES IN THE FAVORED SN BELTS. SO TENDED TO FCST
HIER POPS THAN MODEL CONSENSUS IN THESE AREAS ON MON INTO WED. IN
FACT...FUTURE SHIFTS WL LIKELY NEED TO EXTEND HEADLINE FOR THE ERN
ZNS INTO THIS TIME. ALTHOUGH THERE COULD BE SOME CLIPPER TYPE
SHRTWVS MOVING THRU THIS FLOW...OVERALL DRYNESS OF THE AIRMASS
INDICATES THE SCNTRL COUNTIES WL SEE NOTHING MORE THAN FLURRIES ON
THESE DAYS. WIND CHILLS OVER THE INTERIOR SCENTRAL COULD APRCH ADVY
LVLS AT TIMES. AS THE UPR TROF/ARCTIC BRANCH SLOWLY RETREAT EWD THRU
SE CANADA AFTER WED...A LO PRES DVLPG IN THE PLAINS WITHIN MORE
ACTIVE AND MSTR LADEN POLAR BRANCH WL MOVE TOWARD THE GREAT LKS BY
THU...BRINGING AN END TO THE PERSISTENT COLD/LES BUT THEN THE THREAT
OF AT LEAST A MODERATE SYNOPTIC SN EVENT BY THU.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SATURDAY AFTERNOON)
ISSUED AT 106 PM EST FRI JAN 18 2013
WARM AIR ADVECTION IS PRODUCING WIDESPREAD SNOWFALL ACROSS UPPER MI
EARLY THIS AFTERNOON...WITH THE MORE EXPANSIVE COVERAGE MOVING OUT
FROM THE THREE TAF SITES. A SECONDARY NARROW BAND OF SNOW CURRENTLY
OVER WESTERN UPPER MI IS EXPECTED TO MOVE THROUGH IWD OVER THE NEXT
COUPLE HOURS...AND STAY SOUTH OF CMX AND SAW. WINDS WILL NOT BE A
MAJOR CONCERN AS THEY SHOULD GENERALLY STAY BELOW 10KTS ACROSS THE
AREA. HOWEVER...SOME UPSLOPE FAVORED DIRECTIONS WILL KEEP CIGS LOWER
AT SAW INTO THIS EVENING. AS FOR CMX...WIND DIRECTION IS QUITE
TRICKY FROM THIS EVENING ON AS A TROUGH LOOKS TO PLACE ITSELF RIGHT
OVER THE AREA. PUT VARIABLE WINDS IN THE TAF BEGINNING THIS EVENING
AT CMX...THOUGH FAVORED DIRECTIONS WILL BE FROM BETWEEN NORTH AND
EAST.
A FINAL NOTE...WINDS WILL QUICKLY SHIFT AND INCREASE AT ALL SITES
SATURDAY AFTERNOON...THOUGH TIMING FOR ALL SITES IS STILL UNCERTAIN.
WESTERLY GUSTS OF AT LEAST 30KTS WILL BE POSSIBLE FOR IWD AND CMX AT
OR JUST AFTER THE END OF THIS TAF PERIOD.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 435 AM EST FRI JAN 18 2013
THE COMBINATION OF A DEPARTING HIGH PRESSURE RIDGE AND A WEAK LOW
PRESSURE TROUGH MOVING THROUGH THE UPPER MISSISSIPPI VALLEY TODAY
WILL LEAD TO DIMINISHING WINDS BELOW 20KTS. THESE LIGHT WINDS WILL
REMAIN THROUGH TONIGHT.
EXPECT NW GALES TO 35 TO 40 KTS TO DEVELOP OVER WESTERN LK SUP LATE
SAT IN THE WAKE OF LO PRES MOVING INTO ONTARIO AND THEN OVERSPREAD
THE REST OF THE LK ON SAT NIGHT WHILE INCREASING UP TO 40 TO 45 KTS.
SINCE ARCTIC AIR WILL BE MOVING IN...HEAVY FREEZING SPRAY WILL
DEVELOP AS WELL. GALES/HEAVY FREEZING SPRAY WILL THEN DIMINISH ON SUN
W-E AS LO PRES TO THE E MOVES FARTHER AWAY AND WEAKER PRES GRADIENT
MOVES INTO THE AREA. FOR EARLY NEXT WEEK...EXPECT PERSISTENT NW WINDS
25 TO 30 KTS TO ADVECT ARCTIC AIR OVER LK SUP AND RESULT IN PERIODS
OF HEAVY FREEZING SPRAY.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
LAKE EFFECT SNOW WATCH FROM SATURDAY EVENING THROUGH MONDAY
MORNING FOR MIZ006-007-085.
WINTER WEATHER ADVISORY UNTIL 11 PM EST THIS EVENING FOR MIZ007-
013-014-085.
WINTER WEATHER ADVISORY UNTIL 2 PM CST THIS AFTERNOON FOR MIZ009-
010.
WINTER WEATHER ADVISORY UNTIL 4 PM CST THIS AFTERNOON FOR MIZ011-
012.
LAKE SUPERIOR...
GALE WATCH FROM SATURDAY AFTERNOON THROUGH SUNDAY AFTERNOON FOR
LSZ245>251-265>267.
HEAVY FREEZING SPRAY WATCH FROM LATE SATURDAY NIGHT THROUGH
TUESDAY MORNING FOR LSZ245>251-265>267.
GALE WATCH FROM SATURDAY AFTERNOON THROUGH SUNDAY MORNING FOR
LSZ162-240>244-263-264.
HEAVY FREEZING SPRAY WATCH FROM SATURDAY EVENING THROUGH MONDAY
EVENING FOR LSZ162-240>244-263-264.
LAKE MICHIGAN...
NONE.
&&
$$
UPDATE...JLA
SHORT TERM...SRF
LONG TERM...KC
AVIATION...TK
MARINE...SRF/KC
AREA FORECAST DISCUSSION...UPDATED
NWS MARQUETTE MI
1027 AM EST FRI JAN 18 2013
.UPDATE...
ISSUED AT 1023 AM EST FRI JAN 18 2013
WARM AIR ADVECTION EVIDENT UPSTREAM ON SOUTHERN FRINGE OF UPPER
TROUGH OVER HUDSON BAY/NORTHERN QUEBEC. WARM AIR ADVECTION AND H8-H6
FRONTOGENESIS IN ENTRANCE REGION OF JET STREAK OVER ONTARIO AFFECTS
THE AREA WITH WIDESPREAD SNOW TODAY. H8-H7 FRONTOGENESIS EXPECTED TO
EXPAND EAST ACROSS SOUTHERN TIER THIS MORNING AND ACROSS LK MICHIGAN
ZONES THIS AFTN AND INTO EVENING. 12Z NAM IS CONSISTENT WITH 06Z RUN
AND MATCHES WELL WITH RUC/LOCAL-WRF AND MOST IMPORTANTLY REALITY
BASED ON RADAR/SFC OBS. EXPECT INCREASING SNOW OVER SCNTRL AND
SOUTHEAST CWA THROUGH AFTN...CUTTING OUT FIRST ALONG WI BORDER.
BASED ON LOCAL WRF AND RUC QPF AMOUNTS ALONG WITH EXPECTED SNOW
RATIOS SOMEWHERE IN 10-17:1 RANGE...EXPECT ADVY SNOW AMOUNTS UP TO 5
INCHES OVR PORTIONS OF SCNTRL AND SOUTHEAST/EAST ZONES FOR THIS
EVENT. SOUTHWEST FLOW OFF LK MICHIGAN WITH TEMPS AT INVERSION TOP
AROUND -10C LEADING TO SUFFICIENT OVER-WATER INSTABILITY ALSO COULD
RESULT IN ADDITIONAL INCH OR TWO DUE TO LAKE ENHANCEMENT.
SO...COORD WITH APX AND ISSUED WINTER WEATHER ADVY INTO THE EVENING
FOR DELTA THROUGH LUCE COUNTIES. FARTHER WEST...THERE IS POTENTIAL
FOR ENHANCED BAND OF SNOW TO PUSH TOTALS PAST 3 INCHES...BUT SINCE
HEAVIER SNOW FROM GOGEBIC THROUGH MENOMINEE ONLY LASTS INTO MID AFTN
AND WILL BE PRETTY LOCALIZED...PLAN NOT ISSUE ADVY THERE AND CONTINUE
TO ADDRESS VIA SPECIAL WEATHER STATEMENTS. THAT COULD CHANGE BASED ON
REPORTS THOUGH. BASED ON SOUNDINGS WHEN SNOW CUTS OUT THIS AFTN...SHOULD
SEE TRANSITION TO LGT SNOW AND/OR FREEZING DRIZZLE. &&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 435 AM EST FRI JAN 18 2013
SATELLITE AND RADAR ARE SHOWING THE LAKE EFFECT STILL ONGOING
OVER THE KEWEENAW AND FOR LOCATIONS EAST OF MUNISING. WITH WINDS
CONTINUING TO BACK TO THE WEST AND THEN SOUTHWEST EARLY THIS
MORNING...EXPECT THE LAKE EFFECT TO FOLLOW SUIT AND DEPART THE
EASTERN CWA THIS MORNING. WITH THE INTENSITY OF THE SNOW
DIMINISHING AND A STEADY MOVEMENT EASTWARD...WILL LET THE
ADVISORY EXPIRE AT 12Z. ELSEWHERE...THE HIGH PRESSURE RIDGE OVER
THE CWA AT THIS TIME HAS LED TO A PERIOD OF CLEAR SKIES OVER THE
CENTRAL CWA FOR A PERIOD THIS MORNING...ALLOWING SOME LOCATIONS TO
DROP INTO THE SINGLE DIGITS BELOW ZERO. MID AND HIGH CLOUDS HAVE
STOPPED THE TEMP DROP ALONG THE WISCONSIN BORDER AS THEY MOVE OVER
THE CWA AHEAD OF THE MAIN WEATHER MAKER FOR TODAY.
THE AREA OF LOW PRESSURE IS CURRENTLY IN SOUTHERN
SASKATCHEWAN...BUT AN SURFACE TROUGH STRETCHING SOUTHEAST THROUGH
THE DAKOTAS AND ASSOCIATED H850 TROUGH TO THE NORTHEAST OF THAT HAS
LED TO LIGHT SNOW UNDER THE BROAD WARM AIR ADVECTION THIS MORNING
IN MN AND WESTERN WI. THE LOW IS EXPECTED TO DROP SOUTHEAST THROUGH
NORTHERN MN TODAY AND INTO NORTHERN WISCONSIN OR SOUTHERN UPPER
MICHIGAN BY 00Z SATURDAY. WITH THE RIGHT REAR OF THE UPPER JET
MOVING OVER UPPER MICHIGAN AND THE SHORTWAVE MOVING THROUGH THIS
AFTERNOON AND EARLY EVENING...EXPECT THE LOW TO INTENSIFY SOME. THE
MAIN FOCUS FOR THE SNOW WILL BE THE STRONG H850-700 AND H700-500
WARM AIR ADVECTION AND ASSOCIATED FGEN ON THE H850-600 LAYER. THE
H700-500 WAA MOVES DIRECTLY ACROSS THE CWA AND THAT WILL LEAD THE
BROAD INITIAL SNOW...WHILE THE LOCATION OF THE H850-700 WAA WILL BE
THE DETERMINING FACTOR FOR THE HEAVIER QPF/SNOW. LATEST RUNS SHOW
THIS TO BE FOCUSED OVER THE SOUTHERN HALF OF UPPER MI...BUT IT
SHOULD AFFECT MUCH OF THE CWA TODAY BEFORE QUICKLY EXITING TONIGHT.
DEFINITELY A SHIFT TO THE SOUTH BY ABOUT 10-30 MILES WITH THE AXIS
OF BEST QPF...WITH MOST MODELS NOW SHOWING IT RUNNING ALONG THE WI
BORDER THIS MORNING AND THEN FOCUSING FARTHER NORTHEAST INTO
EASTERN UPPER MICHIGAN AS A SURFACE TROUGH SHARPENS AND ADDITIONAL
MOISTENING OCCURS OFF LAKE MICHIGAN WITH THE WINDS TURNING
SOUTHERLY. THUS...HAVE SHIFTED THE GOING FORECAST SLIGHTLY TOWARDS
THIS LATEST IDEA. SOME OF THE RECENT RAP/HRRR RUNS VARY BACK
AN FORTH ON THAT MORE SOUTHERN IDEA...WHILE THE 00Z ECMWF STILL
KEEPS A MORE NORTHERN SOLUTION. THIS DOES LEAD TO SOME UNCERTAINTY
ON THE NORTHERN SNOWFALL AMOUNTS. THESE TWEAKS ALSO ADJUSTED THE
TIMING SOME WHAT...WITH IT MOVING INTO THE SOUTHWESTERN CWA
AROUND 12Z AND THEN QUICKLY SHIFTING FROM WEST TO EAST AND MUCH OF
THE CWA SEEING SNOW THIS MORNING OR SHORTLY AFTER NOON IN THE
EAST.
WITH THE INITIAL PRECIPITATION OCCURRING WITHOUT TOO MUCH OF THE
LOWER LEVELS BEING SATURATED...THINKING THAT INITIAL SNOW RATIOS
WILL BE IN THE 20-24 TO 1 RANGE. THEN AS THE LOW LEVELS BECOME
SATURATED AND WAA FORCING BECOMES LOCATED BELOW THE DGZ...THERE WILL
BE A QUICK TRANSITION DOWN THROUGH THE TEENS TO A 13 TO 1 SNOW
RATIO. THIS TRANSITION AND IT/S TIMING MAKES FOR A DIFFICULT SNOW
FALL FORECAST...WHICH WILL LIKELY BE RIGHT NEAR ADVISORY LEVELS OVER
EASTERN DELTA...SCHOOLCRAFT...AND SOUTHERN LUCE COUNTIES AS IT MOVES
THROUGH THIS AFTERNOON AND EARLY EVENING. WITH THE ADDITIONAL
MOISTENING AND FORCING FOR THAT AREA BEING ROOTED BELOW THE
DGZ...WONDERING IF THAT WILL BE ENOUGH TO KEEP AMOUNTS AT OR JUST
BELOW THE 3INCH IN 12HR CRITERIA FOR SNOW RATIOS BELOW 20-1. EVEN
WITH THIS SLIGHT SOUTHWARD SHIFT...STILL EXPECT MOST LOCATIONS TO
SEE AN INCH OF SNOW...WITH THE HIGHEST AMOUNTS OVER THE SOUTHERN
U.P. /AROUND 2-2.5 INCHES/ AND OVER THE EAST WHERE LAKE ENHANCEMENT
WILL PUSH VALUES UP TO OR JUST ABOVE 3 INCHES. DUE TO THE
UNCERTAINTY WITH THE NORTHWARD EXTENT ON THE HEAVIEST SNOW AND
CURRENT BORDERLINE ADVISORY AMOUNTS...WILL NOT ISSUE AN ADVISORY AT
THIS POINT BUT KEEP THE MENTION IN THE HWO.
BEHIND THE MAIN WAA PRECIPITATION TODAY...DEEPER MOISTURE REMAINS
OVER THE NORTHERN HALF OF THE CWA TONIGHT AND EXPECT SCATTERED SNOW
SHOWERS THERE AS A SECONDARY WEAK SHORTWAVE MOVES ACROSS LAKE
SUPERIOR. THE KEWEENAW PENINSULA WOULD SEE THE BEST CHANCE FOR
ACCUMULATION...BUT OVERALL AMOUNTS WILL BE LIGHT. SUBSIDENCE WILL BE
ON THE INCREASE OVERNIGHT BEHIND THE SHORTWAVE AND SHOULD BRING AN
END TO THE SNOWFALL. ELSEWHERE...LOW LEVEL MOISTURE WILL BE STUCK
BELOW THE INVERSION FROM THE WAA AROUND H850 THIS AFTERNOON AND
EVENING BEHIND THE SNOW. THIS WILL LEAD TO CLOUDS AND POTENTIAL
FREEZING DRIZZLE CONDITIONS WITH THE LACK OF ICE CRYSTALS IN THE
CLOUDS. WILL CONTINUE THE GOING IDEA IN THE FORECAST...BUT HAVE
OPTED TO SHOW A DIMINISHING TREND OVERNIGHT OVER ALL BUT THE
KEWEENAW AS THE WINDS BECOME A LESS FAVORABLE WHEN THEY SHIFT TO
THE NORTHWEST.
.LONG TERM...(SATURDAY THROUGH THURSDAY)
ISSUED AT 435 AM EST FRI JAN 18 2013
SAT...NUMERICAL GUIDANCE HAS COME INTO VERY GOOD AGREEMENT SHOWING
VIGOROUS SHRTWV DIGGING SEWD FM NEAR LK WINNIPEG AT 12Z SAT INTO WI
BY LATE IN THE DAY. ASSOCIATED SFC LO IS PROGGED TO MOVE ESEWD OVER
LK SUP TO JUST N-NW OF THE SAULT BY 00Z SUN. THE NAM SHOWS A TRACK A
BIT FARTHER N AND FASTER THAN THE OTHER MODELS...BUT TENDED TOWARD
ITS GUIDANCE PER NCEP PREFERENCE. THE TRACK OF THE SFC-H85 LO/MOST
SGNFT DEEP LYR QVECTOR CNVGC/UPR DVGC TO THE N AND MODEST MSTR
RETURN WL TEND TO LIMIT POPS/SN TOTALS. ANOTHER FACTOR AGAINST A
LARGE SN ACCUM IS FCST THIN DGZ BTWN 10-12K FT. FCST H7 SPECIFIC
HUMIDITY ARND 2 G/KG SUGS AN AVG 1-2 INCH ACCUMULATION FOR A 3-6 HR
PERIOD OF SYNOPTIC SN. BEST CHC FOR THE HIER POPS/SN TOTALS WL BE
OVER THE N AND E CWA. THERE MAY BE LTL ACCUMULATION OVER THE FAR
SCNTRL...ESPECIALLY AT MNM FARTHER FM THE SFC LO TRACK. ALTHOUGH
THERE IS SOME CONCERN THE SW FLOW AHEAD OF THE SFC LO MIGHT BRING
SOME ENHANCEMENT OFF LK MI INTO THE ERN ZNS...LOOKS LIKE THE LLVL
FLOW WL BE SHIFTING TOO STEADILY AND H85 TEMPS MIGHT RISE TOO MUCH
TO OPTIMIZE THE CHC FOR SGNFT ENHANCEMENT OF THE EXPECTED SN TOTALS
IN THIS AREA. SOME PLACES OVER THE E COULD SEE UP TO 3 INCHES.
EXPECT DRYING W-E IN THE AFTN AS LARGER SCALE QVECTOR DVGC/MID LVL
DRYING ARRIVES IN THE WAKE OF THE PASSING LO. SOME LES MIGHT ARRIVE
OVER THE W LATE WITH H85 TEMPS FALLING TOWARD -18 TO -20C BY 00Z SUN.
SAT NGT...WITH INCRSG CYC NW FLOW IN THE WAKE OF DEPARTING SHRTWV/
SFC LO ADVECTING H85 TEMPS UNDER -20C INTO THE CWA...EXPECT LES/BLSN
TO DVLP MAINLY IN THE NW WIND FAVORED SN BELTS. STRONG H925 WINDS
FCST UP TO 35-45 KTS MAY BLOW THE SHSN FARTHER INLAND THAN USUAL.
GIVEN FCST MSTR THRU DEEP CONVECTIVE LYR UNDER FCST INVRN BASE NEAR
8K FT WITHIN SHARP CYC NW FLOW...PERSISTENT LLVL CNVGC IN LONG FETCH
OVER THE LK...AND FCST DGZ UP TO 3K FT...OPTED TO ISSUE A LAKE
EFFECT SN WATCH FOR THE ALGER/LUCE/NRN SCHOOLCRAFT COUNTIES.
ALTHOUGH SOME HEAVIER SHSN MIGHT MOVE INTO THE S HALF OF SCHOOLCRAFT
COUNTY AS WELL LATER AT NGT...DID NOT INCLUDE THAT AREA IN THE WATCH
GIVEN SMALLER WINDOW OF OPPORTUNITY BEFORE WINDS DIMINISH ON
SUN...SEE BLO. ALTHOUGH AN LES/BLSN ADVY WL ALMOST CERTAINLY BE
NECESSARY FOR MUCH OF THE NW CWA...OPTED TO HOLD OFF ON A WATCH ATTM
BECAUSE SHORTER FETCH OVER THE WRN LK IS FCST TO RESULT IN LESS
WARMING...WITH DGZ CONFINED TO ONLY THE NEAR SFC LYR PER FCST SDNGS.
HOWEVER...THE COMBINATION OF SMALLER SN FLAKES/STRONG WINDS/BLSN WL
FAVOR SHARPLY REDUCED VSBYS EVEN IF SN TOTALS ARE LESS THAN OVER THE
SN BELTS E OF MQT. STRENTH OF NW FLOW SHOULD ADVECT LK MODERATION
FAR ENUF INLAND TO MITIGATE THE CHILL OVER EVEN THE FAR SCNTRL AND
PREVENT WIND CHILLS FM FALLING BLO ADVY THRESHOLD.
SUN/SUN NGT...THE GRADIENT NW FLOW IS FCST TO DIMINISH FAIRLY
STEADILY THRU THE DAY ON SUN AS SFC LO IN ERN CAN LIFTS TO THE NE.
LES WL PERSIST IN THE NW WIND SN BELTS THRU THIS TIME...SO WENT WITH
CATEGORICAL POPS IN THESE AREAS. MAINTAINED WATCH FOR ALGER/LUCE/N
HALF OF SCHOOLCRAFT COUNTIES THRU SUN NGT. PASSAGE OF SHRTWV/AREA OF
DEEP LYR QVECTOR DNVGC/DEEP MSTR ON SUN AFTN/EVNG MIGHT BRING SOME
-SHSN/FLURRIES TO EVEN THE SCNTRL. AS THE LLVL FLOW BACKS A BIT MORE
SUN NGT AND ADVECTS MORE UNMODIFIED ARCTIC AIR INTO THAT AREA...WIND
CHILLS MIGHT AT LEAST APRCH ADVY CRITERIA OVER THE SCNTRL.
EXTENDED PERIOD...THE FIRST HALF OF NEXT WEEK WL BE DOMINATED BY
DEEP UPR TROF OVER ERN NAMERICA WITH NW FLOW OVER THE CWA HELD IN
PLACE BY HI LATITUDE BLOCKING...A CLASSIC NEGATIVE NAO PATTERN THAT
FAVORS WELL BLO NORMAL TEMPS OVER THE GRT LKS. EXPECT PERSISTENT NW
FLOW OF ARCTIC AIR WITH H85 TEMPS AS LO AS -25 TO -30C TO BRING
NEARLY CONTINUOUS LES IN THE FAVORED SN BELTS. SO TENDED TO FCST
HIER POPS THAN MODEL CONSENSUS IN THESE AREAS ON MON INTO WED. IN
FACT...FUTURE SHIFTS WL LIKELY NEED TO EXTEND HEADLINE FOR THE ERN
ZNS INTO THIS TIME. ALTHOUGH THERE COULD BE SOME CLIPPER TYPE
SHRTWVS MOVING THRU THIS FLOW...OVERALL DRYNESS OF THE AIRMASS
INDICATES THE SCNTRL COUNTIES WL SEE NOTHING MORE THAN FLURRIES ON
THESE DAYS. WIND CHILLS OVER THE INTERIOR SCENTRAL COULD APRCH ADVY
LVLS AT TIMES. AS THE UPR TROF/ARCTIC BRANCH SLOWLY RETREAT EWD THRU
SE CANADA AFTER WED...A LO PRES DVLPG IN THE PLAINS WITHIN MORE
ACTIVE AND MSTR LADEN POLAR BRANCH WL MOVE TOWARD THE GREAT LKS BY
THU...BRINGING AN END TO THE PERSISTENT COLD/LES BUT THEN THE THREAT
OF AT LEAST A MODERATE SYNOPTIC SN EVENT BY THU.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SATURDAY MORNING)
ISSUED AT 645 AM EST FRI JAN 18 2013
A WARM FRONT MOVING THROUGH MINNESOTA AND WISCONSIN WILL PRODUCE
AND AREA OF SNOW THAT SLIDES FROM WEST TO EAST ACROSS UPPER
MICHIGAN. THE SNOW WILL HAVE THE GREATEST INFLUENCE ON
KIWD/KSAW...WITH SLIGHTLY LIGHTER SNOW AT KCMX. KIWD SHOULD SEE THE
VISIBILITIES DROP AT OR SHORTLY AFTER TAF EFFECTIVE TIME...WITH
KCMX/KSAW AROUND MID MORNING. THERE IS SOME UNCERTAINTY IN THE
EXACT LOCATION OF THE HEAVIEST SNOW...BUT FELT CONFIDENT ENOUGH TO
DROP VISIBILITIES TO LIFR AT BOTH KIWD/KSAW. WITH SOUTHERLY
FLOW...EXPECT THE CEILINGS TO FALL NEAR OR SLIGHTLY BELOW
IFR DURING THE HEAVIEST SNOW.
WITH THE SNOW DEPARTING DURING THE EARLY AFTERNOON...LINGERING LOW
LEVEL MOISTURE WILL KEEP LOW END MVFR CEILINGS WITH ISOLATED SNOW
SHOWERS OR PATCHY FREEZING DRIZZLE. WASN/T CONFIDENT ENOUGH IN
TIMING/LOCATION OF THE FREEZING DRIZZLE TO PUT IT IN...SO FUTURE
SHIFTS WILL NEED TO MONITOR. AS WINDS SHIFT TO THE WEST
OVERNIGHT...THE CEILINGS SHOULD LIFT SOME...BUT THE NEXT LOW
PRESSURE WILL BE APPROACHING WESTERN LAKE SUPERIOR AT THAT TIME AND
KEEP THEM FROM RISING TOO MUCH AT KIWD/KCMX.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 435 AM EST FRI JAN 18 2013
THE COMBINATION OF A DEPARTING HIGH PRESSURE RIDGE AND A WEAK LOW
PRESSURE TROUGH MOVING THROUGH THE UPPER MISSISSIPPI VALLEY TODAY
WILL LEAD TO DIMINISHING WINDS BELOW 20KTS. THESE LIGHT WINDS WILL
REMAIN THROUGH TONIGHT.
EXPECT NW GALES TO 35 TO 40 KTS TO DEVELOP OVER WESTERN LK SUP LATE
SAT IN THE WAKE OF LO PRES MOVING INTO ONTARIO AND THEN OVERSPREAD
THE REST OF THE LK ON SAT NIGHT WHILE INCREASING UP TO 40 TO 45 KTS.
SINCE ARCTIC AIR WILL BE MOVING IN...HEAVY FREEZING SPRAY WILL
DEVELOP AS WELL. GALES/HEAVY FREEZING SPRAY WILL THEN DIMINISH ON SUN
W-E AS LO PRES TO THE E MOVES FARTHER AWAY AND WEAKER PRES GRADIENT
MOVES INTO THE AREA. FOR EARLY NEXT WEEK...EXPECT PERSISTENT NW WINDS
25 TO 30 KTS TO ADVECT ARCTIC AIR OVER LK SUP AND RESULT IN PERIODS
OF HEAVY FREEZING SPRAY.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
LAKE EFFECT SNOW WATCH FROM SATURDAY EVENING THROUGH MONDAY
MORNING FOR MIZ006-007-085.
WINTER WEATHER ADVISORY UNTIL 11 PM EST THIS EVENING FOR MIZ007-
013-014-085.
LAKE SUPERIOR...
GALE WATCH FROM SATURDAY AFTERNOON THROUGH SUNDAY AFTERNOON FOR
LSZ245>251-265>267.
HEAVY FREEZING SPRAY WATCH FROM LATE SATURDAY NIGHT THROUGH
TUESDAY MORNING FOR LSZ245>251-265>267.
GALE WATCH FROM SATURDAY AFTERNOON THROUGH SUNDAY MORNING FOR
LSZ162-240>244-263-264.
HEAVY FREEZING SPRAY WATCH FROM SATURDAY EVENING THROUGH MONDAY
EVENING FOR LSZ162-240>244-263-264.
LAKE MICHIGAN...
NONE.
&&
$$
UPDATE...JLA
SHORT TERM...SRF
LONG TERM...KC
AVIATION...SRF
MARINE...SRF/KC
AREA FORECAST DISCUSSION
NWS DULUTH MN
822 PM CST SAT JAN 19 2013
.UPDATE...PUSHED THE WIND ADVISORY START TIME TO NOW AS IT WAS NOT
DUE TO START UNTIL 03Z. GNA HAS GUSTED TO 57 MPH IN THE LAST HALF
HOUR. REST OF THE FORECAST ON TRACK.
&&
.PREV DISCUSSION... /ISSUED 631 PM CST SAT JAN 19 2013/
UPDATE...DROPPED THE WIND ADVISORY FROM THE SOUTHERN MN ZONES.
GUSTY WINDS STILL EXPECTED UNTIL NEAR 06Z. WITH THE EXPECTED
CLEARING TREND...DROP MIN TEMPS A BIT. NO OTHER CHANGES TO
HEADLINES.
PREV DISCUSSION... /ISSUED 525 PM CST SAT JAN 19 2013/
AVIATION...00Z TAFS.
TIGHT PRESSURE GRADIENT OVER THE FA AT THE BEGINNING OF THE
FORECAST...BUT WILL LOOSEN ITS GRIP THROUGH THE EVENING AND GUSTY
WINDS WILL DIMINISH AROUND 06Z. MVFR WITH AREAS OF IFR WILL
IMPROVE TO VFR ABOUT THE SAME TIME THE GUSTY WINDS DIMINISH.
EXPECT A MID DECK OF CLOUDS AFTER 18Z SUNDAY AHEAD OF A SHORT WAVE
TROF MOVING THROUGH THE FA.
PREV DISCUSSION... /ISSUED 336 PM CST SAT JAN 19 2013/
SHORT TERM.../NOW - SUNDAY NIGHT/
THE MAIN CHALLENGES FOR THIS FORECAST INCLUDE 1) THE THREAT OF
STRONG WINDS ACROSS THE NORTHLAND THROUGH TONIGHT IN THE WAKE OF A
STRONG COLD FRONT...2) THE THREAT OF LAKE EFFECT SNOW FOR THE
GOGEBIC RANGE AND 3) THE THREAT OF HAZARDOUS WIND CHILL VALUES
TONIGHT AND TOMORROW MORNING. THE MODELS ARE IN REASONABLE
AGREEMENT...SO LEANED ON A BLEND. THE LATEST HIGH RESOLUTIONS
MODELS INDICATE STRONG WIND GUSTS ALONG THE NORTH SHORE
TONIGHT...SO ISSUED A WIND ADVISORY FOR THE NORTH SHORE THAT IS
SEPARATE FROM THE WIND ADVISORY FOR PARTS OF EAST CENTRAL
MINNESOTA AND NORTHWESTERN WISCONSIN.
AT 2130Z...THERE WAS A STRONG CLIPPER SYSTEM CENTERED OVER UPPER
PENINSULA MICHIGAN. THE NORTHLAND HAD STRONG W TO NW WINDS...WHICH
WERE GENERALLY STRENGTHENING IN THE WAKE OF THE CLIPPER. THE
NORTHLAND HAD CLOUDY SKIES. TEMPERATURES RANGED FROM THE LOW TO
MID 30S IN THE FAR EASTERN FA TO THE SINGLE DIGITS IN THE FAR NW
FA.
THROUGH TONIGHT...THE CLIPPER SYSTEM WILL CONTINUE TO MOVE EAST.
THE STRONG NW WINDS CARRYING QUITE THE ARCTIC BLAST WILL CONTINUE
TO INCREASE LATE THIS AFTERNOON...PERHAPS PEAK EARLY THIS
EVENING...THEN GRADUALLY RELAX THROUGH THE REST OF THE NIGHT. THE
EXCEPTION COULD BE ALONG THE IMMEDIATE NORTH SHORE WHERE
WINDS...ESPECIALLY GUSTS...WILL LIKELY STRENGTHEN INTO THIS
EVENING AND PEAK AROUND MIDNIGHT. THIS IS BASED ON THE LATEST RUNS
OF THE HRRR AND LOCAL WRF MODELS. THOSE MODELS SUGGEST WIND GUSTS
UP TO 50 KT. NOT SURE IF THE GUSTS WILL BE THAT STRONG...BUT
DECIDED TO ISSUE A WIND ADVISORY FOR THE NORTH SHORE THROUGH 09Z
TONIGHT FOR GUSTS UP TO 50 MPH. THE CURRENT WIND ADVISORY FROM
SOUTHERN CASS COUNTY TO BURNETT COUNTY STILL LOOKS GOOD THROUGH
03Z. WIND CHILL VALUES WILL PLUMMET TONIGHT WITH THE FALLING
TEMPERATURES...AND THE CURRENT WIND CHILL ADVISORY FOR TONIGHT AND
INTO TOMORROW MORNING DOES NOT NEED ANY CHANGES. LAKE EFFECT SNOW
SHOWERS WILL INCREASE ACROSS THE SOUTH SHORE TONIGHT...ESPECIALLY
THE GOGEBIC RANGE IN IRON COUNTY...AS THE STRONG COLD NW WINDS
DEVELOP OVER WESTERN LAKE SUPERIOR. WILL NOT BE MAKING CHANGES TO
THE CURRENT LAKE EFFECT SNOW ADVISORY FOR IRON COUNTY AS PARTS OF
THE COUNTY COULD GET SEVERAL INCHES OF SNOW THROUGH SUNDAY
MORNING.
SUNDAY AND SUNDAY NIGHT...IT WILL BE A PARTICULARLY COLD DAY
ACROSS THE NORTHLAND WITH MUCH OF REGION NOT EVEN REACHING ZERO
DEGREES. LAKE EFFECT SNOW SHOWERS WILL LIKELY CONTINUE FOR THE
SOUTH SHORE. ANOTHER WIND CHILL ADVISORY OR WARNING WILL LIKELY BE
NEEDED. SOME PARTS OF FAR NORTHERN MINNESOTA COULD HAVE WIND CHILL
VALUES APPROACHING 50 DEGREES BELOW ZERO.
LONG TERM.../MONDAY - FRIDAY NIGHT/
MODELS SHOWING GOOD AGREEMENT THAT THE CORE OF COLDEST H85-H50 AIR
PUSHES INTO THE NORTHERN AREAS EARLY MONDAY MORNING...SWINGING
THROUGH THE NORTHLAND THROUGH 00Z TUESDAY. AT THIS TIME WIND CHILL
VALUES IN THE NEIGHBORHOOD OF NEGATIVE 30 TO 50 ARE EXPECTED EARLY
MONDAY MORNING WITH VERY LITTLE IMPROVEMENT THROUGH THE DAY. THE
LATEST ECM/GFS SUGGEST THAT THE WRN LAKE SUPERIOR REGION REMAINS ON
THE BACK EDGE OF THE ARCTIC AIR MASS THROUGH MUCH OF THE WEEK WITH A
PERSIST ANT NORTHWEST FLOW. HAVE KEPT POPS ACROSS THE SOUTH SHORE
ZONES FOR AN ONGOING PERIOD OF LAKE EFFECT SNOW AS WELL.
AVIATION.../18Z TAF ISSUANCE/
MVFR CIGS WITH -SN AND BLSN WILL PREVAIL THROUGH 00Z..THEN
GRADUALLY IMPROVING TO VFR GENERALLY AFTER 06Z. NORTHWEST WINDS
WILL INCREASE THROUGH THE AFTERNOON WITH GUSTS OF 30 TO 35 KTS
COMMON ACROSS THE FORECAST ARES THROUGH THE 20Z TO 06Z PERIOD.
HIGHER GUSTS AROUND 40 KT WILL BE POSSIBLE AT THE KBRD AND KDLH
TERMINALS AROUND 00Z...WITH THE STRONGEST GUSTS OF 45-50 KT
EXPECTED ALONG THE NORTH SHORE OF LAKE SUPERIOR AFTER 03Z.
&&
.POINT TEMPS/POPS...
DLH -10 0 -21 -9 / 10 10 10 10
INL -20 -5 -30 -12 / 10 10 10 10
BRD -12 1 -22 -10 / 10 10 10 0
HYR -9 3 -18 -7 / 20 10 10 10
ASX -3 6 -13 -4 / 60 30 50 40
&&
.DLH WATCHES/WARNINGS/ADVISORIES...
MN...WIND CHILL ADVISORY UNTIL NOON CST SUNDAY FOR MNZ010>012-018>021-
025-026-033>038.
WIND ADVISORY UNTIL 3 AM CST SUNDAY FOR MNZ020-021.
WI...WIND CHILL ADVISORY FROM MIDNIGHT TONIGHT TO NOON CST SUNDAY FOR
WIZ001>004-006>009.
LAKE EFFECT SNOW ADVISORY UNTIL NOON CST SUNDAY FOR WIZ004.
LS...NONE.
&&
$$
SHORT TERM...GSF
AREA FORECAST DISCUSSION
NWS DULUTH MN
631 PM CST SAT JAN 19 2013
.UPDATE...DROPPED THE WIND ADVISORY FROM THE SOUTHERN MN ZONES.
GUSTY WINDS STILL EXPECTED UNTIL NEAR 06Z. WITH THE EXPECTED
CLEARING TREND...DROP MIN TEMPS A BIT. NO OTHER CHANGES TO
HEADLINES.
&&
.PREV DISCUSSION... /ISSUED 525 PM CST SAT JAN 19 2013/
AVIATION...00Z TAFS.
TIGHT PRESSURE GRADIENT OVER THE FA AT THE BEGINNING OF THE
FORECAST...BUT WILL LOOSEN ITS GRIP THROUGH THE EVENING AND GUSTY
WINDS WILL DIMINISH AROUND 06Z. MVFR WITH AREAS OF IFR WILL
IMPROVE TO VFR ABOUT THE SAME TIME THE GUSTY WINDS DIMINISH.
EXPECT A MID DECK OF CLOUDS AFTER 18Z SUNDAY AHEAD OF A SHORT WAVE
TROF MOVING THROUGH THE FA.
PREV DISCUSSION... /ISSUED 336 PM CST SAT JAN 19 2013/
SHORT TERM.../NOW - SUNDAY NIGHT/
THE MAIN CHALLENGES FOR THIS FORECAST INCLUDE 1) THE THREAT OF
STRONG WINDS ACROSS THE NORTHLAND THROUGH TONIGHT IN THE WAKE OF A
STRONG COLD FRONT...2) THE THREAT OF LAKE EFFECT SNOW FOR THE
GOGEBIC RANGE AND 3) THE THREAT OF HAZARDOUS WIND CHILL VALUES
TONIGHT AND TOMORROW MORNING. THE MODELS ARE IN REASONABLE
AGREEMENT...SO LEANED ON A BLEND. THE LATEST HIGH RESOLUTIONS
MODELS INDICATE STRONG WIND GUSTS ALONG THE NORTH SHORE
TONIGHT...SO ISSUED A WIND ADVISORY FOR THE NORTH SHORE THAT IS
SEPARATE FROM THE WIND ADVISORY FOR PARTS OF EAST CENTRAL
MINNESOTA AND NORTHWESTERN WISCONSIN.
AT 2130Z...THERE WAS A STRONG CLIPPER SYSTEM CENTERED OVER UPPER
PENINSULA MICHIGAN. THE NORTHLAND HAD STRONG W TO NW WINDS...WHICH
WERE GENERALLY STRENGTHENING IN THE WAKE OF THE CLIPPER. THE
NORTHLAND HAD CLOUDY SKIES. TEMPERATURES RANGED FROM THE LOW TO
MID 30S IN THE FAR EASTERN FA TO THE SINGLE DIGITS IN THE FAR NW
FA.
THROUGH TONIGHT...THE CLIPPER SYSTEM WILL CONTINUE TO MOVE EAST.
THE STRONG NW WINDS CARRYING QUITE THE ARCTIC BLAST WILL CONTINUE
TO INCREASE LATE THIS AFTERNOON...PERHAPS PEAK EARLY THIS
EVENING...THEN GRADUALLY RELAX THROUGH THE REST OF THE NIGHT. THE
EXCEPTION COULD BE ALONG THE IMMEDIATE NORTH SHORE WHERE
WINDS...ESPECIALLY GUSTS...WILL LIKELY STRENGTHEN INTO THIS
EVENING AND PEAK AROUND MIDNIGHT. THIS IS BASED ON THE LATEST RUNS
OF THE HRRR AND LOCAL WRF MODELS. THOSE MODELS SUGGEST WIND GUSTS
UP TO 50 KT. NOT SURE IF THE GUSTS WILL BE THAT STRONG...BUT
DECIDED TO ISSUE A WIND ADVISORY FOR THE NORTH SHORE THROUGH 09Z
TONIGHT FOR GUSTS UP TO 50 MPH. THE CURRENT WIND ADVISORY FROM
SOUTHERN CASS COUNTY TO BURNETT COUNTY STILL LOOKS GOOD THROUGH
03Z. WIND CHILL VALUES WILL PLUMMET TONIGHT WITH THE FALLING
TEMPERATURES...AND THE CURRENT WIND CHILL ADVISORY FOR TONIGHT AND
INTO TOMORROW MORNING DOES NOT NEED ANY CHANGES. LAKE EFFECT SNOW
SHOWERS WILL INCREASE ACROSS THE SOUTH SHORE TONIGHT...ESPECIALLY
THE GOGEBIC RANGE IN IRON COUNTY...AS THE STRONG COLD NW WINDS
DEVELOP OVER WESTERN LAKE SUPERIOR. WILL NOT BE MAKING CHANGES TO
THE CURRENT LAKE EFFECT SNOW ADVISORY FOR IRON COUNTY AS PARTS OF
THE COUNTY COULD GET SEVERAL INCHES OF SNOW THROUGH SUNDAY
MORNING.
SUNDAY AND SUNDAY NIGHT...IT WILL BE A PARTICULARLY COLD DAY
ACROSS THE NORTHLAND WITH MUCH OF REGION NOT EVEN REACHING ZERO
DEGREES. LAKE EFFECT SNOW SHOWERS WILL LIKELY CONTINUE FOR THE
SOUTH SHORE. ANOTHER WIND CHILL ADVISORY OR WARNING WILL LIKELY BE
NEEDED. SOME PARTS OF FAR NORTHERN MINNESOTA COULD HAVE WIND CHILL
VALUES APPROACHING 50 DEGREES BELOW ZERO.
LONG TERM.../MONDAY - FRIDAY NIGHT/
MODELS SHOWING GOOD AGREEMENT THAT THE CORE OF COLDEST H85-H50 AIR
PUSHES INTO THE NORTHERN AREAS EARLY MONDAY MORNING...SWINGING
THROUGH THE NORTHLAND THROUGH 00Z TUESDAY. AT THIS TIME WIND CHILL
VALUES IN THE NEIGHBORHOOD OF NEGATIVE 30 TO 50 ARE EXPECTED EARLY
MONDAY MORNING WITH VERY LITTLE IMPROVEMENT THROUGH THE DAY. THE
LATEST ECM/GFS SUGGEST THAT THE WRN LAKE SUPERIOR REGION REMAINS ON
THE BACK EDGE OF THE ARCTIC AIR MASS THROUGH MUCH OF THE WEEK WITH A
PERSIST ANT NORTHWEST FLOW. HAVE KEPT POPS ACROSS THE SOUTH SHORE
ZONES FOR AN ONGOING PERIOD OF LAKE EFFECT SNOW AS WELL.
AVIATION.../18Z TAF ISSUANCE/
MVFR CIGS WITH -SN AND BLSN WILL PREVAIL THROUGH 00Z..THEN
GRADUALLY IMPROVING TO VFR GENERALLY AFTER 06Z. NORTHWEST WINDS
WILL INCREASE THROUGH THE AFTERNOON WITH GUSTS OF 30 TO 35 KTS
COMMON ACROSS THE FORECAST ARES THROUGH THE 20Z TO 06Z PERIOD.
HIGHER GUSTS AROUND 40 KT WILL BE POSSIBLE AT THE KBRD AND KDLH
TERMINALS AROUND 00Z...WITH THE STRONGEST GUSTS OF 45-50 KT
EXPECTED ALONG THE NORTH SHORE OF LAKE SUPERIOR AFTER 03Z.
&&
.POINT TEMPS/POPS...
DLH -10 0 -21 -9 / 10 10 10 10
INL -20 -5 -30 -12 / 10 10 10 10
BRD -12 1 -22 -10 / 10 10 10 0
HYR -9 3 -18 -7 / 20 10 10 10
ASX -3 6 -13 -4 / 60 30 50 40
&&
.DLH WATCHES/WARNINGS/ADVISORIES...
MN...WIND CHILL ADVISORY UNTIL NOON CST SUNDAY FOR MNZ010>012-018>021-
025-026-033>038.
WIND ADVISORY UNTIL 3 AM CST SUNDAY FOR MNZ020-021.
WI...WIND CHILL ADVISORY FROM MIDNIGHT TONIGHT TO NOON CST SUNDAY FOR
WIZ001>004-006>009.
LAKE EFFECT SNOW ADVISORY UNTIL NOON CST SUNDAY FOR WIZ004.
LS...NONE.
&&
$$
SHORT TERM...GSF
AREA FORECAST DISCUSSION
NWS DULUTH MN
525 PM CST SAT JAN 19 2013
.AVIATION...00Z TAFS.
TIGHT PRESSURE GRADIENT OVER THE FA AT THE BEGINNING OF THE
FORECAST...BUT WILL LOOSEN ITS GRIP THROUGH THE EVENING AND GUSTY
WINDS WILL DIMINISH AROUND 06Z. MVFR WITH AREAS OF IFR WILL
IMPROVE TO VFR ABOUT THE SAME TIME THE GUSTY WINDS DIMINISH.
EXPECT A MID DECK OF CLOUDS AFTER 18Z SUNDAY AHEAD OF A SHORT WAVE
TROF MOVING THROUGH THE FA.
&&
.PREV DISCUSSION... /ISSUED 336 PM CST SAT JAN 19 2013/
SHORT TERM.../NOW - SUNDAY NIGHT/
THE MAIN CHALLENGES FOR THIS FORECAST INCLUDE 1) THE THREAT OF
STRONG WINDS ACROSS THE NORTHLAND THROUGH TONIGHT IN THE WAKE OF A
STRONG COLD FRONT...2) THE THREAT OF LAKE EFFECT SNOW FOR THE
GOGEBIC RANGE AND 3) THE THREAT OF HAZARDOUS WIND CHILL VALUES
TONIGHT AND TOMORROW MORNING. THE MODELS ARE IN REASONABLE
AGREEMENT...SO LEANED ON A BLEND. THE LATEST HIGH RESOLUTIONS
MODELS INDICATE STRONG WIND GUSTS ALONG THE NORTH SHORE
TONIGHT...SO ISSUED A WIND ADVISORY FOR THE NORTH SHORE THAT IS
SEPARATE FROM THE WIND ADVISORY FOR PARTS OF EAST CENTRAL
MINNESOTA AND NORTHWESTERN WISCONSIN.
AT 2130Z...THERE WAS A STRONG CLIPPER SYSTEM CENTERED OVER UPPER
PENINSULA MICHIGAN. THE NORTHLAND HAD STRONG W TO NW WINDS...WHICH
WERE GENERALLY STRENGTHENING IN THE WAKE OF THE CLIPPER. THE
NORTHLAND HAD CLOUDY SKIES. TEMPERATURES RANGED FROM THE LOW TO
MID 30S IN THE FAR EASTERN FA TO THE SINGLE DIGITS IN THE FAR NW
FA.
THROUGH TONIGHT...THE CLIPPER SYSTEM WILL CONTINUE TO MOVE EAST.
THE STRONG NW WINDS CARRYING QUITE THE ARCTIC BLAST WILL CONTINUE
TO INCREASE LATE THIS AFTERNOON...PERHAPS PEAK EARLY THIS
EVENING...THEN GRADUALLY RELAX THROUGH THE REST OF THE NIGHT. THE
EXCEPTION COULD BE ALONG THE IMMEDIATE NORTH SHORE WHERE
WINDS...ESPECIALLY GUSTS...WILL LIKELY STRENGTHEN INTO THIS
EVENING AND PEAK AROUND MIDNIGHT. THIS IS BASED ON THE LATEST RUNS
OF THE HRRR AND LOCAL WRF MODELS. THOSE MODELS SUGGEST WIND GUSTS
UP TO 50 KT. NOT SURE IF THE GUSTS WILL BE THAT STRONG...BUT
DECIDED TO ISSUE A WIND ADVISORY FOR THE NORTH SHORE THROUGH 09Z
TONIGHT FOR GUSTS UP TO 50 MPH. THE CURRENT WIND ADVISORY FROM
SOUTHERN CASS COUNTY TO BURNETT COUNTY STILL LOOKS GOOD THROUGH
03Z. WIND CHILL VALUES WILL PLUMMET TONIGHT WITH THE FALLING
TEMPERATURES...AND THE CURRENT WIND CHILL ADVISORY FOR TONIGHT AND
INTO TOMORROW MORNING DOES NOT NEED ANY CHANGES. LAKE EFFECT SNOW
SHOWERS WILL INCREASE ACROSS THE SOUTH SHORE TONIGHT...ESPECIALLY
THE GOGEBIC RANGE IN IRON COUNTY...AS THE STRONG COLD NW WINDS
DEVELOP OVER WESTERN LAKE SUPERIOR. WILL NOT BE MAKING CHANGES TO
THE CURRENT LAKE EFFECT SNOW ADVISORY FOR IRON COUNTY AS PARTS OF
THE COUNTY COULD GET SEVERAL INCHES OF SNOW THROUGH SUNDAY
MORNING.
SUNDAY AND SUNDAY NIGHT...IT WILL BE A PARTICULARLY COLD DAY
ACROSS THE NORTHLAND WITH MUCH OF REGION NOT EVEN REACHING ZERO
DEGREES. LAKE EFFECT SNOW SHOWERS WILL LIKELY CONTINUE FOR THE
SOUTH SHORE. ANOTHER WIND CHILL ADVISORY OR WARNING WILL LIKELY BE
NEEDED. SOME PARTS OF FAR NORTHERN MINNESOTA COULD HAVE WIND CHILL
VALUES APPROACHING 50 DEGREES BELOW ZERO.
LONG TERM.../MONDAY - FRIDAY NIGHT/
MODELS SHOWING GOOD AGREEMENT THAT THE CORE OF COLDEST H85-H50 AIR
PUSHES INTO THE NORTHERN AREAS EARLY MONDAY MORNING...SWINGING
THROUGH THE NORTHLAND THROUGH 00Z TUESDAY. AT THIS TIME WIND CHILL
VALUES IN THE NEIGHBORHOOD OF NEGATIVE 30 TO 50 ARE EXPECTED EARLY
MONDAY MORNING WITH VERY LITTLE IMPROVEMENT THROUGH THE DAY. THE
LATEST ECM/GFS SUGGEST THAT THE WRN LAKE SUPERIOR REGION REMAINS ON
THE BACK EDGE OF THE ARCTIC AIR MASS THROUGH MUCH OF THE WEEK WITH A
PERSIST ANT NORTHWEST FLOW. HAVE KEPT POPS ACROSS THE SOUTH SHORE
ZONES FOR AN ONGOING PERIOD OF LAKE EFFECT SNOW AS WELL.
AVIATION.../18Z TAF ISSUANCE/
MVFR CIGS WITH -SN AND BLSN WILL PREVAIL THROUGH 00Z..THEN
GRADUALLY IMPROVING TO VFR GENERALLY AFTER 06Z. NORTHWEST WINDS
WILL INCREASE THROUGH THE AFTERNOON WITH GUSTS OF 30 TO 35 KTS
COMMON ACROSS THE FORECAST ARES THROUGH THE 20Z TO 06Z PERIOD.
HIGHER GUSTS AROUND 40 KT WILL BE POSSIBLE AT THE KBRD AND KDLH
TERMINALS AROUND 00Z...WITH THE STRONGEST GUSTS OF 45-50 KT
EXPECTED ALONG THE NORTH SHORE OF LAKE SUPERIOR AFTER 03Z.
&&
.POINT TEMPS/POPS...
DLH -12 0 -21 -9 / 10 10 10 10
INL -19 -5 -30 -12 / 10 10 10 10
BRD -12 1 -22 -10 / 10 10 10 0
HYR -5 3 -18 -7 / 20 10 10 10
ASX -1 6 -13 -4 / 60 30 50 40
&&
.DLH WATCHES/WARNINGS/ADVISORIES...
MN...WIND CHILL ADVISORY FROM 9 PM THIS EVENING TO NOON CST SUNDAY
FOR MNZ010>012-018>021-025-026-033>038.
WIND ADVISORY UNTIL 9 PM CST THIS EVENING FOR MNZ033-034-036-038.
WIND ADVISORY UNTIL 3 AM CST SUNDAY FOR MNZ020-021.
WI...WIND ADVISORY UNTIL 9 PM CST THIS EVENING FOR WIZ006.
WIND CHILL ADVISORY FROM MIDNIGHT TONIGHT TO NOON CST SUNDAY FOR
WIZ001>004-006>009.
LAKE EFFECT SNOW ADVISORY UNTIL NOON CST SUNDAY FOR WIZ004.
LS...NONE.
&&
$$
AVIATION...GSF
AREA FORECAST DISCUSSION...UPDATED
NWS BILLINGS MT
913 PM MST THU JAN 17 2013
.SHORT TERM...VALID FOR FRI AND SAT...
WINDS WERE BELOW ADVISORY SPEEDS THIS EVENING IN THE KLVM AND BIG
TIMBER AREAS. MANUAL ANALYSIS OF THE SURFACE PRESSURE GRADIENT
REVEALED THAT THE GRADIENT WAS MUCH FLATTER THAN DEPICTED ON LAPS
OR THE MODELS DUE TO THE 1045 HIGH CENTERED OVER THE PARK. THE
STRENGTH OF THE GRADIENT BETWEEN KLWT AND KIDA WAS 26 MB AT 03Z.
GIVEN A MORE STABLE AIRMASS...THIS GRADIENT WOULD TYPICALLY
SUPPORT WARNING CRITERIA WIND SPEEDS AT KLVM AND NYE.
HOWEVER...THE LOW-LEVELS WERE A BIT UNSTABLE THIS EVENING. WHILE
THEY SHOULD STABILIZE A BIT OVERNIGHT PER RAP AND WRF BUFKIT
SOUNDINGS...ADVISORY CURRENTLY IN EFFECT SHOULD COVER THE
SITUATION. THE FLATTER GRADIENT MAY NOT ALLOW WIND SPEEDS TO REACH
ADVISORY CRITERIA AT BIG TIMBER. SINCE CURRENT WIND SPEEDS WERE
30-35 MPH IN THIS AREA...AND WITH AIRMASS STABILIZING A BIT MORE
OVERNIGHT...HAVE NO STRONG REASON TO CHANGE THE HIGHLIGHT IN THIS
AREA. LATEST MODELS SHOWED A STRONG PRESSURE GRADIENT PERSISTING
INTO FRI NIGHT WHEN A COLD FRONT BACKDOORS INTO THE AREA. THE
RELAXING GRADIENT WILL ALLOW WIND SPEEDS TO DIMINISH AT THAT TIME.
EXPECT WINDY CONDITIONS FROM KBIL W AHEAD OF THIS FRONT.
TEMPERATURES THIS EVENING WERE IN THE 30S TO LOWER 40S IN MOST
AREAS. HIGH CLOUDS WERE SINKING S THROUGH THE REGION PER IR
SATELLITE IMAGERY. COMBINATION OF WIND AND CLOUDS WILL KEEP
TEMPERATURES A BIT HIGHER THAN FORECAST SO HAVE RAISED MINS TOWARD
THE NEW METBC GUIDANCE. ALSO ADJUSTED CLOUD COVER ACROSS THE AREA.
NEW MODEL RUNS CONTINUED TO SUPPORT A WARM AND DRY DAY ON FRI WITH
850 MB TEMPERATURES AROUND +7 DEGREES C. ARTHUR
.LONG TERM...VALID FOR SUN...MON...TUE...WED...THU...
MINIMAL CHANGES TO THE EXTENDED PERIOD FORECAST THIS AFTERNOON.
MODELS REMAIN IN GOOD AGREEMENT THROUGH THE PERIOD. THE END OF
WORK WEEK WEATHER SYSTEM ALSO APPEARS TO BE COMING INTO BETTER
AGREEMENT WITH LATEST MODELS RUNS.
THE EXTENDED FORECAST BEGINS SUNDAY...AS A BACKDOOR FRONT PUSHES
INTO THE REGION. THIS DOES NOT APPEAR TO BE A SIGNIFICANTLY WET
SYSTEM...SO NOT EXPECTING A LOT OF ACCUMULATIONS...BUT CANNOT
RULE OUT SOME SNOW. THEREFORE...HAVE CONTINUED WITH GOING POPS AT
THIS TIME. THE TIMING OF THIS SYSTEM DOES APPEAR TO HAVE SPED UP
SLIGHTLY...AND THE ASSOCIATED SURFACE LOW APPEARS TO HAVE
STRENGTHENED A BIT AS WELL. ADDITIONALLY...THESE SYSTEMS SEEM TO
REACH THE MOUNTAINS MORE OFTEN THAN NOT AND SEEM TO BE SOMEWHAT
STUBBORN IN THEIR DEPARTURES...SO COOLED TEMPS FOR SUNDAY AND
MONDAY...ESPECIALLY ACROSS THE WEST...FROM KBIL TO THE MOUNTAINS.
THE NEXT SEVERAL DAYS WILL SEE A WARMING TREND UNDER PERSISTENT DRY
NORTHWEST FLOW...BEGINNING MONDAY. THERE WILL BE SEVERAL
SHORTWAVES THROUGH THE FLOW...BUT DRY CONDITIONS AND DOWNSLOPE
FLOW SHOULD LIMIT CLOUD DEVELOPMENT. TEMPS ARE PROGGED TO WARM UP
MUCH MORE QUICKLY THAN INDICATED IN THE INHERITED FORECAST. NOT
SEEING MUCH TO INHIBIT WARM UP WITH VERY LIMITED SNOW COVER AND
CLOUD COVER THROUGH THE PERIOD UNLESS THE COLD FRONT STALLS...SO
HAVE INCREASED TEMPS FOR TUESDAY AND WEDNESDAY...ESPECIALLY ON
WEDNESDAY IN ADVANCE OF NEXT APPROACHING WEATHER SYSTEM.
MODELS APPEAR TO BE COMING INTO BETTER AGREEMENT FOR ANOTHER BROAD
PACIFIC TROF TO PUSH THROUGH THE REGION BEGINNING LATE WEDNESDAY AND
THROUGH THURSDAY. CONTINUING WITH GOING POPS AT THIS
TIME. ALSO LOWERED TEMPS SLIGHTLY FOR THURSDAY...AS FRONT SHOULD
BE THROUGH BY THAT TIME. AAG
&&
.AVIATION...
SOUTHWEST WINDS WILL INCREASE OVER WESTERN ROUTES TONIGHT AND
CONTINUE INTO FRIDAY NIGHT. GUSTS WILL EXCEED 50KTS AT KLVM. GUSTS
WILL APPROACH 35KTS AT KBIL BY LATE FRIDAY MORNING. LLWS WILL ALSO
BE A CONCERN AT KSHR AND KMLS WITH INCREASING NORTHWEST WINDS
ALOFT. OTHERWISE...VFR CONDITIONS WILL PREVAIL THROUGH THE NIGHT
WITH JUST SOME MID AND HIGH LEVEL CLOUDINESS EXPECTED. TWH
&&
.PRELIMINARY POINT TEMP/POPS...
FRI SAT SUN MON TUE WED THU
-----------------------------------------------------------
BIL 031/051 023/029 009/022 008/027 018/039 023/042 024/035
00/N 00/B 03/S 21/N 10/N 01/B 22/J
LVM 034/048 026/038 012/027 015/032 021/040 024/040 021/033
00/N 00/N 02/S 21/N 10/N 02/S 23/J
HDN 024/050 019/029 006/020 003/024 014/038 018/041 022/035
00/N 00/B 13/S 21/B 11/B 01/B 23/J
MLS 025/046 016/017 000/013 905/017 010/031 015/036 020/033
00/B 00/B 23/S 22/B 21/B 01/B 23/J
4BQ 026/047 017/023 002/018 901/021 011/034 017/038 020/033
00/U 00/B 23/S 22/B 21/B 01/B 23/J
BHK 025/042 013/015 903/009 908/011 007/027 014/034 018/031
00/B 00/N 23/S 22/B 21/B 01/B 22/J
SHR 019/052 019/032 007/023 005/030 014/041 018/042 021/033
00/U 00/B 02/S 21/B 10/B 01/B 23/J
&&
.BYZ WATCHES/WARNINGS/ADVISORIES...
MT...WIND ADVISORY IN EFFECT UNTIL 6 AM MST SATURDAY FOR ZONES
41-65-66.
WY...NONE.
&&
$$
WEATHER.GOV/BILLINGS
AREA FORECAST DISCUSSION
NWS BURLINGTON VT
1234 PM EST FRI JAN 18 2013
.SYNOPSIS...
COLD SURFACE HIGH PRESSURE WILL KEEP HIGH TEMPERATURES IN THE
TEENS ACROSS THE NORTH COUNTRY TODAY. A WARM FRONT WILL BRING
LIGHT SNOW TO THE NORTH COUNTRY LATE TONIGHT INTO SATURDAY MORNING.
SATURDAY WILL BE BREEZY AND MILD WITH HIGH TEMPS REACHING THE
UPPER 30S. ANOTHER FRONTAL SYSTEM BRINGS SNOW SHOWERS TO THE
REGION SATURDAY NIGHT AND SUNDAY ALONG WITH SOME STRONG WINDS.
COLDER TEMPERATURES RETURN FOR MONDAY AND TUESDAY.
&&
.NEAR TERM /UNTIL 7 PM THIS EVENING/...
AS OF 1149 AM EST FRIDAY...CLEAR SKIES IN PLACE ACROSS THE NORTH
COUNTRY JUST BEFORE NOONTIME. SURFACE HIGH PRESSURE RIDGE OVER THE
FORECAST AREA WILL SHIFT EWD INTO NH/MAINE THIS EVENING. 850MB
TEMPS GRADUALLY MODERATING...BUT STILL -20 TO -22C PER RAP GUIDANCE
AT 18Z. MAX TEMPS WILL BE ABOUT 10 DEGREES BELOW NORMAL...ONLY
REACHING INTO THE MID-UPPER TEENS THIS AFTERNOON...WITH A FEW
LOWER 20S IN THE IMMEDIATE CT RIVER VALLEY. CLOUDS WILL BEGIN TO
INCREASE ACROSS NORTHERN NEW YORK THIS EVENING ON SOUTHWEST FLOW
AHEAD OF APPROACHING WARM FRONT.
&&
.SHORT TERM /7 PM THIS EVENING THROUGH SUNDAY/...
AS OF 230 AM EST FRIDAY...THE SHORT TERM FORECAST PERIOD WILL BE
PRETTY ACTIVE WITH TWO DIFFERENT LOW PRESSURE SYSTEMS AFFECTING
THE NORTH COUNTRY. SURFACE HIGH PRESSURE SLIDES EASY AWAY FROM
THE REGION AND WARM FRONT MOVES ACROSS THE AREA TONIGHT BRINGING
CHANCE FOR SOME LIGHT SNOW TO THE NORTH COUNTRY. BEST FORCING
WILL BE ALONG OUR NORTHERN BORDER...WITH 1-3" OF SNOW EXPECTED.
OTHER AREAS WILL ONLY HAVE UP TO 1". LOW PRESSURE SYSTEM MOVES
INTO THE SAINT LAWRENCE VALLEY OVERNIGHT. CLOUDS AND LIGHT SNOW
WILL KEEP TEMPERATURES FROM DROPPING TOO DRASTICALLY
OVERNIGHT...AND OVERNIGHT MIN TEMPS WILL BE CLOSE TO FRIDAY`S MAX
TEMPS. SATURDAY WILL BE MILD...ABOUT TEN DEGREES ABOVE NORMAL AS
WARM AIR ADVECTION CONTINUES ACROSS THE NORTH COUNTRY. WILL STILL
HAVE MENTION FOR SOME LIGHT SNOW DURING THE DAY
SATURDAY...ESPECIALLY EARLIER IN THE DAY AND ACROSS OUR NORTHERN
AND HIGHER ELEVATION ZONES. GUSTY SOUTH-SOUTHWEST WINDS WILL
DEVELOP DURING THE DAY AS THE WARM FRONT LIFTS NORTH OF THE CWA.
SATURDAY NIGHT A SECOND STRONGER LOW PRESSURE SYSTEM WILL
APPROACH...BUT THEN PASS NORTH OF...THE NORTH COUNTRY. WILL HAVE
CHANCE FOR SOME SNOW SHOWERS WITH THIS FRONTAL PASSAGE
SUNDAY...BUT BIGGER CONCERN THEN SNOW WOULD BE STRONG WINDS WITH
TIGHT PRESSURE GRADIENT IN PLACE. MAY SEE ADDITIONAL LIGHT SNOW
ACCUMULATIONS OF 1-3" IN NORTHERN NEW YORK. SATURDAY NIGHT AND
SUNDAY WILL ALSO BOTH BE MILD FOR THIS TIME OF YEAR WITH TEMPS
ONLY DROPPING IN THE UPPER 20S SATURDAY NIGHT DUE TO
WINDS...CLOUD COVER...AND SNOW SHOWERS. ON SUNDAY MAX
TEMPERATURES WILL BE EARLY IN THE DAY HEAD OF THE FRONT...BUT
WILL STILL BE ABOUT 5 DEGREES ABOVE NORMAL WITH LOWER 30S
EXPECTED.
&&
.LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/...
AS OF 354 AM EST FRIDAY...NO SIGNIFICANT PRECIPITATION EVENTS EXPECTED
DURING THE EXTENDED PERIOD. THE BIG STORY WILL BE THE ARCTIC CHILL
WITH THE COLDEST AIRMASS OF THE SEASON EXPECTED TO TAKE UP RESIDENCE
OVER THE NORTH COUNTRY. CORE OF THE COLD AIR WILL BE OVER THE AREA
TUESDAY INTO WEDNESDAY WHEN TEMPERATURES WILL AVERAGE AROUND 20
DEGREES BELOW NORMAL.
COLD ADVECTION CONTINUES SUNDAY NIGHT ALONG WITH CHANCE FEW SNOW
SHOWERS IN WAKE OF DEPARTING LOW PRESSURE...WHICH WILL BE MAKING ITS
WAY UP THROUGH CANADIAN MARITIMES. WINDS STILL GUSTY DURING THE
EVENING...THEN EASING OVERNIGHT. WEAK HIGH PRESSURE WILL BUILD IN AT
THE SURFACE MONDAY...BUT UPPER TROUGH WILL REMAIN OVER THE REGION
KEEPING CLOUDS AND SLIGHT CHANCE SNOW SHOWERS OVER THE AREA.
UPPER LEVEL TROUGH WILL DIG SOUTH OF THE FORECAST AREA LATER MONDAY
INTO TUESDAY. SOME INDICATIONS THAT WEAK SURFACE LOW MAY SPIN
UP OVER MID ATLANTIC STATES MONDAY AND THEN TRACK WELL SOUTH OF
NEW ENGLAND MONDAY NIGHT INTO TUESDAY...WITH PRECIP ASSOCIATED
WITH IT REMAINING MOSTLY TO OUR SOUTH. A SERIES OF DISTURBANCES
EMBEDDED IN THE FLOW ALOFT MAY BRING A FEW SNOW SHOWERS OR
FLURRIES TO THE FORECAST AREA AT TIMES...BUT NOTHING OF CONSEQUENCE.
CHANCES FOR SNOW SHOWERS INCREASE LATER THURSDAY AS HIGH PRESSURE
MOVES EAST OF THE AREA AND WARM FRONT APPROACHES FROM THE
SOUTH AND WEST. VERY COLD AIRMASS WILL BE ENTRENCHED OVER THE
REGION FOR THE FIRST HALF OF THE WEEK. 850 MB TEMPS AROUND -20C ON
MONDAY...AND -20C TO AS LOW AS -30C OVER NORTHERN AREAS TUESDAY
INTO WEDNESDAY. THE RESULT WILL BE TEMPERATURES MUCH BELOW NORMAL
MONDAY THROUGH WEDNESDAY WITH HIGHS GENERALLY IN THE SINGLE
NUMBERS AND TEENS...WITH NIGHTTIME READINGS 0 TO 20 BELOW. COLDEST
DAYS LOOKING TO BE TUESDAY AND WEDNESDAY WHEN MANY NORTHERN
LOCALES MAY STRUGGLE TO BREAK ZERO.
&&
.AVIATION /18Z FRIDAY THROUGH WEDNESDAY/...
THROUGH 12Z SATURDAY...CLEAR SKIES WILL TREND TO BKN/OVC LATER
THIS EVENING AS HIGH PRESSURE SLIDES EAST OF THE REGION AND MID
LEVEL MOISTURE SPREADS EAST FROM THE GREAT LAKES WITH THE APPROACH
OF A WARM FRONT. CONDITIONS WILL DETERIORATE TO MVFR/IFR FROM WEST
TO EAST ACROSS THE REGION BETWEEN 00Z-06Z SUNDAY IN DEVELOPING
SNOW. MVFR/IFR SNOW CONTINUES THROUGH 12Z...THEN TAPERS OFF AS THE
FRONT SHIFTS NORTH OF THE REGION...EXCEPT FOR ACROSS NORTHERN NEW
YORK WHERE MVFR SNOWS WILL CONTINUE A BIT LONGER. WINDS TREND LIGHT
TO MODERATE SOUTH/SOUTHWESTERLY THIS AFTERNOON/NIGHT AND BECOME GUSTY
TO 20 KTS AFTER 12Z SATURDAY.
OUTLOOK 18Z SATURDAY THROUGH WEDNESDAY...
18Z SATURDAY THROUGH 06Z SUNDAY...A MIX OF VFR/MVFR WITH SNOW
SHOWERS IN THE VICINITY LOWERING CONDITIONS TO MVFR/IFR AT TIMES.
06Z SUNDAY THROUGH 00Z MONDAY...MVFR/IFR AT TIMES IN SNOW SHOWERS ASSOCIATED
WITH ARCTIC FRONT. WIND GUSTS FROM WEST-SOUTHWEST OF 30-40 KTS POSSIBLE.
00Z MONDAY ONWARD...IMPROVING TO VFR UNDER HIGH PRESSURE.
&&
.BTV WATCHES/WARNINGS/ADVISORIES...
VT...NONE.
NY...NONE.
&&
$$
SYNOPSIS...NEILES
NEAR TERM...BANACOS/NEILES
SHORT TERM...NEILES
LONG TERM...RJS
AVIATION...LAHIFF
AREA FORECAST DISCUSSION
NWS BURLINGTON VT
1155 AM EST FRI JAN 18 2013
.SYNOPSIS...
COLD SURFACE HIGH PRESSURE WILL KEEP HIGH TEMPERATURES IN THE
TEENS ACROSS THE NORTH COUNTRY TODAY. A WARM FRONT WILL BRING
LIGHT SNOW TO THE NORTH COUNTRY LATE TONIGHT INTO SATURDAY MORNING.
SATURDAY WILL BE BREEZY AND MILD WITH HIGH TEMPS REACHING THE
UPPER 30S. ANOTHER FRONTAL SYSTEM BRINGS SNOW SHOWERS TO THE
REGION SATURDAY NIGHT AND SUNDAY ALONG WITH SOME STRONG WINDS.
COLDER TEMPERATURES RETURN FOR MONDAY AND TUESDAY.
&&
.NEAR TERM /UNTIL 7 PM THIS EVENING/...
AS OF 1149 AM EST FRIDAY...CLEAR SKIES IN PLACE ACROSS THE NORTH
COUNTRY JUST BEFORE NOONTIME. SURFACE HIGH PRESSURE RIDGE OVER THE
FORECAST AREA WILL SHIFT EWD INTO NH/MAINE THIS EVENING. 850MB
TEMPS GRADUALLY MODERATING...BUT STILL -20 TO -22C PER RAP GUIDANCE
AT 18Z. MAX TEMPS WILL BE ABOUT 10 DEGREES BELOW NORMAL...ONLY
REACHING INTO THE MID-UPPER TEENS THIS AFTERNOON...WITH A FEW
LOWER 20S IN THE IMMEDIATE CT RIVER VALLEY. CLOUDS WILL BEGIN TO
INCREASE ACROSS NORTHERN NEW YORK THIS EVENING ON SOUTHWEST FLOW
AHEAD OF APPROACHING WARM FRONT.
&&
.SHORT TERM /7 PM THIS EVENING THROUGH SUNDAY/...
AS OF 230 AM EST FRIDAY...THE SHORT TERM FORECAST PERIOD WILL BE
PRETTY ACTIVE WITH TWO DIFFERENT LOW PRESSURE SYSTEMS AFFECTING
THE NORTH COUNTRY. SURFACE HIGH PRESSURE SLIDES EASY AWAY FROM
THE REGION AND WARM FRONT MOVES ACROSS THE AREA TONIGHT BRINGING
CHANCE FOR SOME LIGHT SNOW TO THE NORTH COUNTRY. BEST FORCING
WILL BE ALONG OUR NORTHERN BORDER...WITH 1-3" OF SNOW EXPECTED.
OTHER AREAS WILL ONLY HAVE UP TO 1". LOW PRESSURE SYSTEM MOVES
INTO THE SAINT LAWRENCE VALLEY OVERNIGHT. CLOUDS AND LIGHT SNOW
WILL KEEP TEMPERATURES FROM DROPPING TOO DRASTICALLY
OVERNIGHT...AND OVERNIGHT MIN TEMPS WILL BE CLOSE TO FRIDAY`S MAX
TEMPS. SATURDAY WILL BE MILD...ABOUT TEN DEGREES ABOVE NORMAL AS
WARM AIR ADVECTION CONTINUES ACROSS THE NORTH COUNTRY. WILL STILL
HAVE MENTION FOR SOME LIGHT SNOW DURING THE DAY
SATURDAY...ESPECIALLY EARLIER IN THE DAY AND ACROSS OUR NORTHERN
AND HIGHER ELEVATION ZONES. GUSTY SOUTH-SOUTHWEST WINDS WILL
DEVELOP DURING THE DAY AS THE WARM FRONT LIFTS NORTH OF THE CWA.
SATURDAY NIGHT A SECOND STRONGER LOW PRESSURE SYSTEM WILL
APPROACH...BUT THEN PASS NORTH OF...THE NORTH COUNTRY. WILL HAVE
CHANCE FOR SOME SNOW SHOWERS WITH THIS FRONTAL PASSAGE
SUNDAY...BUT BIGGER CONCERN THEN SNOW WOULD BE STRONG WINDS WITH
TIGHT PRESSURE GRADIENT IN PLACE. MAY SEE ADDITIONAL LIGHT SNOW
ACCUMULATIONS OF 1-3" IN NORTHERN NEW YORK. SATURDAY NIGHT AND
SUNDAY WILL ALSO BOTH BE MILD FOR THIS TIME OF YEAR WITH TEMPS
ONLY DROPPING IN THE UPPER 20S SATURDAY NIGHT DUE TO
WINDS...CLOUD COVER...AND SNOW SHOWERS. ON SUNDAY MAX
TEMPERATURES WILL BE EARLY IN THE DAY HEAD OF THE FRONT...BUT
WILL STILL BE ABOUT 5 DEGREES ABOVE NORMAL WITH LOWER 30S
EXPECTED.
&&
.LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/...
AS OF 354 AM EST FRIDAY...NO SIGNIFICANT PRECIPITATION EVENTS EXPECTED
DURING THE EXTENDED PERIOD. THE BIG STORY WILL BE THE ARCTIC CHILL
WITH THE COLDEST AIRMASS OF THE SEASON EXPECTED TO TAKE UP RESIDENCE
OVER THE NORTH COUNTRY. CORE OF THE COLD AIR WILL BE OVER THE AREA
TUESDAY INTO WEDNESDAY WHEN TEMPERATURES WILL AVERAGE AROUND 20
DEGREES BELOW NORMAL.
COLD ADVECTION CONTINUES SUNDAY NIGHT ALONG WITH CHANCE FEW SNOW
SHOWERS IN WAKE OF DEPARTING LOW PRESSURE...WHICH WILL BE MAKING ITS
WAY UP THROUGH CANADIAN MARITIMES. WINDS STILL GUSTY DURING THE
EVENING...THEN EASING OVERNIGHT. WEAK HIGH PRESSURE WILL BUILD IN AT
THE SURFACE MONDAY...BUT UPPER TROUGH WILL REMAIN OVER THE REGION
KEEPING CLOUDS AND SLIGHT CHANCE SNOW SHOWERS OVER THE AREA.
UPPER LEVEL TROUGH WILL DIG SOUTH OF THE FORECAST AREA LATER MONDAY
INTO TUESDAY. SOME INDICATIONS THAT WEAK SURFACE LOW MAY SPIN
UP OVER MID ATLANTIC STATES MONDAY AND THEN TRACK WELL SOUTH OF
NEW ENGLAND MONDAY NIGHT INTO TUESDAY...WITH PRECIP ASSOCIATED
WITH IT REMAINING MOSTLY TO OUR SOUTH. A SERIES OF DISTURBANCES
EMBEDDED IN THE FLOW ALOFT MAY BRING A FEW SNOW SHOWERS OR
FLURRIES TO THE FORECAST AREA AT TIMES...BUT NOTHING OF CONSEQUENCE.
CHANCES FOR SNOW SHOWERS INCREASE LATER THURSDAY AS HIGH PRESSURE
MOVES EAST OF THE AREA AND WARM FRONT APPROACHES FROM THE
SOUTH AND WEST. VERY COLD AIRMASS WILL BE ENTRENCHED OVER THE
REGION FOR THE FIRST HALF OF THE WEEK. 850 MB TEMPS AROUND -20C ON
MONDAY...AND -20C TO AS LOW AS -30C OVER NORTHERN AREAS TUESDAY
INTO WEDNESDAY. THE RESULT WILL BE TEMPERATURES MUCH BELOW NORMAL
MONDAY THROUGH WEDNESDAY WITH HIGHS GENERALLY IN THE SINGLE
NUMBERS AND TEENS...WITH NIGHTTIME READINGS 0 TO 20 BELOW. COLDEST
DAYS LOOKING TO BE TUESDAY AND WEDNESDAY WHEN MANY NORTHERN
LOCALES MAY STRUGGLE TO BREAK ZERO.
&&
.AVIATION /18Z FRIDAY THROUGH WEDNESDAY/...
THROUGH 12Z SATURDAY...VFR CONDITIONS TODAY WITH HIGH PRESSURE
OVER THE REGION. SKIES TREND BKN/OVC LATER THIS AFTERNOON AS HIGH
SLIDES EAST AND MID LEVEL MOISTURE SPREADS EAST FROM THE GREAT
LAKES WITH APPROACH OF WARM FRONT. CONDITIONS WILL DETERIORATE TO
MVFR/IFR FROM WEST TO EAST ACROSS THE REGION BETWEEN 00Z-06Z
SUNDAY IN DEVELOPING SNOW. WINDS TRENDING LIGHT TO MODERATE
SOUTH/SOUTHWESTERLY THIS AFTERNOON/NIGHT AND OCCASIONALLY GUSTY
TO 20 KTS AT NRN NY TERMINALS AFTER 18Z AND IN CHAMPLAIN VALLEY
LATER FRIDAY NIGHT.
OUTLOOK 12Z SATURDAY THROUGH TUESDAY...
12Z SATURDAY THROUGH 06Z SUNDAY...LOWERING TO MVFR/IFR AT TIMES
IN SNOW SHOWERS ASSOCIATED WITH WARM FRONT.
06Z SUNDAY THROUGH 06Z MONDAY...MVFR/IFR AT TIMES IN SNOW SHOWERS ASSOCIATED
WITH ARCTIC FRONT. WIND GUSTS FROM WEST-SOUTHWEST OF 30-40 KTS POSSIBLE.
06Z MONDAY ONWARD...IMPROVING TO VFR.
&&
.BTV WATCHES/WARNINGS/ADVISORIES...
VT...NONE.
NY...NONE.
&&
$$
SYNOPSIS...NEILES
NEAR TERM...BANACOS/NEILES
SHORT TERM...NEILES
LONG TERM...RJS
AVIATION...RJS
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
1252 AM EST FRI JAN 18 2013
.SYNOPSIS...
AN INTENSE AND QUICK MOVING AREA OF LOW PRESSURE WILL BRING
WIND...RAIN AND A RETURN TO CHILLY TEMPERATURES OVERNIGHT. THE
WINTER CHILL WILL PERSIST INTO THE WEEKEND AND THEN PERIODICALLY
BE REINFORCED BY SUCCESSIVE DRY COLD FRONTS THROUGH MUCH OF
NEXT WEEK.
&&
.NEAR TERM /UNTIL 6 AM THIS MORNING/...
AS OF 12:45 AM FRIDAY...NO FURTHER REPORTS OF FROZEN PRECIP OVER
THE PAST HOUR. RADAR LOOPS SHOW ONE LAST BAND OF RAIN DROPPING SE
ACROSS THE COASTAL PLAIN. THIS WILL BE OFFSHORE WITHIN THE NEXT
COUPLE OF HOURS...FOLLOWED BY A BRIEF PERIOD OF DRIZZLE...THEN
RAPIDLY IMPROVING CONDITIONS. THAT IS...IF ONE CONSIDERS COLD AND
BREEZY TO BE AN IMPROVEMENT. PREVIOUS DISCUSSIONS FOLLOW:
BASED ON MULTIPLE REPORTS RELAYED THROUGH TV METEOROLOGISTS OF
SNOW MIXING WITH THE RAIN FARTHER SOUTH THAN ASOS/AWOS REPORTS HAD
INDICATED...I HAVE UPDATED THE FORECAST FOR THE NEXT 3-5 HOURS TO
INCLUDE MIXED PRECIP TYPES AS FAR SOUTH AS
DARLINGTON...DILLON...THE COLUMBUS/BLADEN COUNTY LINE...AND
BURGAW. THE LATEST SEVERAL RUC MODEL RUNS SHOW FREEZING LEVELS
SHOULD BE FALLING BELOW 2000 FT AGL SHORTLY IN THE BENNETTSVILLE
AND LUMBERTON AREAS WHICH MAY SUPPORT MORE SNOW MAKING IT TO THE
SURFACE. MY THOUGHTS STILL HAVE NOT CHANGED WITH RESPECT TO THE
VERY LOW LIKELIHOOD OF ANY ACCUMULATIONS REGARDLESS OF HOW MUCH
SNOW MIXES IN. PREVIOUS DISCUSSION FROM 1000 PM FOLLOWS...
THE COLD FRONT IS NOW WELL OFFSHORE. THE BAND OF HEAVY RAINFALL AND
EMBEDDED CONVECTION WITHIN THE ENHANCED ZONE OF ASCENT IS OFFSHORE
TOO. ATTENTION NOW TURNS TO THE UPPER LEVEL LOW CURRENTLY OVER
UPSTATE SOUTH CAROLINA. THIS SWIRLING BALL OF COLD AIR ALOFT IS
FORECAST BY ALL MODEL GUIDANCE TO MOVE NORTHEASTWARD TO THE SOUTHERN
CHESAPEAKE BAY BY 3-5 AM. STEEP LAPSE RATES ALOFT AND DEEP MOISTURE
ASSOCIATED WITH THIS LOW ARE PRODUCING WIDESPREAD LIGHT
PRECIPITATION EXTENDING FROM UPSTATE SOUTH CAROLINA ACROSS THE
WESTERN TWO-THIRDS OF NORTH CAROLINA. UNDERNEATH THIS UPPER
SYSTEM...COLD AIR BEING PULLED SOUTH BEHIND THE DEPARTING SURFACE
LOW HAS CHANGED RAIN OVER TO SNOW ALONG AND NORTH OF A LINE FROM
JUST NORTH OF CHARLOTTE TO ASHEBORO TO RALEIGH. WHILE THE CHANCES
FOR MEASURABLE SNOW HAVE NEVER BEEN GOOD IN OUR FORECAST
AREA...THERE REMAINS A SMALL POTENTIAL THAT THE RAIN COULD END MIXED
WITH SNOW ACROSS BENNETTSVILLE...LUMBERTON AND ELIZABETHTOWN AFTER
MIDNIGHT. NO ACCUMULATIONS ARE EXPECTED DUE TO ABOVE-FREEZING AIR
TEMPERATURES AND WELL-ABOVE FREEZING GROUND TEMPERATURES.
ALSO...I SPOKE TO A REPRESENTATIVE WITH THE EMERGENCY MANAGEMENT
AGENCY IN COLUMBUS COUNTY WHO REPORTED FAIRLY WIDESPREAD AND
SUBSTANTIAL DAMAGE FROM THE LINE OF SHOWERS THAT MOVED THROUGH THERE
AROUND 645 PM. WE WILL BE SENDING A STORM SURVEY TEAM OUT TO THE
CHADBOURN COMMUNITY IN WESTERN COLUMBUS COUNTY TOMORROW MORNING TO
SURVEY AND CLASSIFY THE DAMAGE THERE.
&&
.SHORT TERM /6 AM THIS MORNING THROUGH SATURDAY NIGHT/...
AS OF 2 PM THURSDAY...WINTER IS BACK. IT WILL BE A CHILLY AND
BRISK START TO THE DAY FRI AS THE PRESSURE GRADIENT WILL REMAIN
RATHER TIGHT BETWEEN STRONG HIGH PRESSURE ACROSS THE OHIO AND
TENNESSEE VALLEYS AND LOW PRESSURE INTENSIFYING SE OF NEW ENGLAND.
THE GRADIENT WILL SLACKEN THROUGH THE AFTERNOON AND WIND
GUSTS...UP TO 25 TO 30 MPH...WILL DIMINISH. CHILLY TEMPS FRI
MORNING...ESPECIALLY IN COMPARISON TO RECENT DAYS...COUPLED WITH
THE WIND...WILL MAKE IT FEEL AS IF IT WERE IN THE MID 20S TO LOWER
30S. EVEN WITH BRIGHT SUNSHINE...TEMPS ARE NOT EXPECTED TO RISE
QUICKLY AS 850 MB TEMPS WILL START THE DAY JUST BELOW ZERO DEG.
PREVIOUS THINKING HAS NOT CHANGED AND WILL FORECAST HIGHS BELOW 50
DEGREES IN MOST PLACES...WITH MID 40S MOST COMMON. GOOD
RADIATIONAL COOLING IS EXPECTED FRI NIGHT AS HIGH PRESSURE REACHES
THE AREA. CLEAR SKIES AND VIRTUALLY CALM WIND WILL ALLOW EVE TEMPS
TO QUICKLY DROP AS DEWPOINTS DURING THIS TIME WILL BE WELL DOWN IN
THE 20S. OVERNIGHT LOWS ARE EXPECTED TO REACH THE MID AND UPPER
20S WITH SOME LOWER 20S WHERE RADIATIONAL COOLING MAXIMIZES
LONGEST.
CHILLY SURFACE HIGH PRESSURE WILL STILL BE IN PLACE ON SAT...BUT THE
WESTWARD EXTENT OF THE RIDGE WILL BEGIN TO BREAK DOWN DURING THE
AFTERNOON. SOME WEAK RETURN OF MILDER AIR AHEAD OF THE LEADING EDGE
OF THE NEXT COLD SURGE IS EXPECTED BY SAT AFTERNOON. THEREFORE...
THE SECOND HALF OF THE PERIOD SHOULD NOT BE AS CHILLY AND CLOSER TO
VALUES MORE TYPICAL OF MID JAN. WILL FORECAST HIGHS IN THE LOWER TO
MID 50S SAT. DEWPOINTS WILL BE CLIMBING THROUGH THE DAY SAT AND WITH
NIGHTFALL...TEMPS WILL NOT BE ABLE TO FALL AS RAPIDLY OR AS FAR AS
FRI NIGHT. DO NOT SEE A REASON TO STRAY TOO FAR FROM MODEL CONSENSUS
WHICH BRINGS LOWS TO THE MID AND UPPER 30S OVERNIGHT SAT.
&&
.LONG TERM /SUNDAY THROUGH THURSDAY/...
AS OF 2 PM THURSDAY...THE LONG TERM APPEARS TO BE ENTIRELY RAIN-FREE
AND INCREASINGLY COLD. SUNDAY WILL BE THE ONE MILD DAY AHEAD OF THE
FIRST SHOT OF COLDER AIR SLATED TO ARRIVE LATE IN THE DAY OR AT
NIGHT. THIS FIRST BOUNDARY WILL BE FAIRLY WEAK LEADING TO
TEMPERATURES ONLY A FEW DEGREES SHY OF CLIMO ON MONDAY...EVEN THOUGH
SOME 8 DEGREES COLDER THAN SUNDAY. DEEPENING MID LEVEL TROUGHINESS
AROUND HUDSON BAY VORTEX SENDS MUCH STRONGER SHOT OF COLD AIR
ADVECTION INTO THE SOUTHEAST MONDAY NIGHT. THERE IS STILL SOME
QUESTION AS TO THE ARCTIC CONTENT OF THE AIRMASS THAT FOLLOWS. THE
GFS FOR EXAMPLE HAS 850MB TEMPS RANGING FROM 0 TO -4C SOUTH TO NORTH
ACROSS THE REGION 00Z WED WHEREAS THE ECMWF (FROM 00Z) HAS -6 TO
-12C. THE CANADIAN IS CLOSER IN CAMP TO THE ECWMF IN SHOWING TRUE
ARCTIC AIR INVADING THE SOUTHEAST ALTHOUGH ITS PROGRESS IS SLIGHTLY
HELD UP BY A CLIPPER TYPE OF WAVE THAT MAY OR MAY NOT COME TO PASS.
CURRENT FORECAST WEIGHTED TOWARDS THE COLDER CONSENSUS.
&&
.AVIATION /06Z FRIDAY THROUGH TUESDAY/...
AS OF 06Z...PERIODS OF MVFR AND POSSIBLE IFR INTO THE EARLY MORNING
HOURS DUE TO LOWERED CIGS. BY DAYBREAK...VFR WILL PREVAIL AND
CONTINUE THROUGH THE REMAINDER OF THE VALID PERIOD.
MAY SEE SOME LINGERING VCSH OVERNIGHT BUT OVERALL MVFR ARE
ANTICIPATED OVERNIGHT WITH WINDS BECOMING NORTHERLY AT ALL SITES
AOB 15 KTS INTO THE MORNING HOURS. ANY RESIDUAL LOWERED CIGS FROM
OVERNIGHT WILL QUICKLY IMPROVE BY MORNING AS THE COLD FRONT PUSHES
OUT OF THE AREA. VFR WILL PREVAIL FOR THE REMAINDER OF THE PERIOD.
NORTH-NORTHEAST WINDS WILL CONTINUE THROUGHOUT THE DAY WITH GUSTS
UP TO 25 KTS. EXPECT GUSTS TO SUBSIDE INTO THE EARLY EVENING
HOURS.
EXTENDED OUTLOOK...VFR THROUGH THE EXTENDED.
&&
.MARINE...
NEAR TERM /THROUGH TONIGHT/...
AS OF 12:45 AM FRIDAY...GALE FORCE GUSTS PERSIST OVER THE WATERS.
NO CHANGES TO THE FORECAST WITH THE LATEST UPDATE. PREVIOUS
DISCUSSIONS FOLLOWS:
THE ONLY SIGNIFICANT CHANGE TO THE FORECAST WAS TO RAISE SEA
HEIGHTS BY 1-2 FEET BASED ON CURRENTLY REPORTED WAVE OBSERVATIONS
FROM THE FRYING PAN SHOALS BUOY...THE NEARSHORE WRIGHTSVILLE BEACH
BUOY...AND THE OCEAN CREST PIER WAVE GAUGE. WITH THE COLD FRONT
AND ATTENDANT LOW PRESSURE AREA NOW OFFSHORE WINDS WILL BECOME
NORTHERLY OVERNIGHT WITH GALE FORCE GUSTS REMAINING POSSIBLE.
PREVIOUS DISCUSSION FROM 630 PM FOLLOWS...
A COLD FRONT HAS SLID IN FROM THE NORTH AND LIES BETWEEN
WRIGHTSVILLE BEACH AND CAROLINA BEACH ALONG THE NORTH CAROLINA
COASTLINE. NORTHEAST WINDS NORTH OF THE BOUNDARY CONTRAST WITH SOUTH
WINDS ELSEWHERE. ANOTHER PORTION OF THE COLD FRONT IS QUICKLY
OVERTAKING FROM THE WEST...DRIVEN BY STRONG SURFACE LOW PRESSURE NOW
JUST NORTH OF MYRTLE BEACH. THIS LOW AND FRONT WILL SWEEP ACROSS THE
ENTIRE FORECAST AREA IN THE NEXT COUPLE OF HOURS...FOLLOWED BY GUSTY
WESTERLY WINDS THAT SHOULD TURN MORE NORTHERLY WITH TIME OVERNIGHT.
A GALE WARNING REMAINS IN EFFECT MORE FOR GUSTS THAN FOR SUSTAINED
WIND SPEEDS. THE STRONGEST WINDS ARE EXPECTED THIS EVENING WITH
CONVECTIVE SHOWERS ALONG THE FRONT...AND THEN AGAIN AFTER MIDNIGHT
AS THE LOW MOVES OFFSHORE AND COLD AIR POURS INTO THE REGION FROM
THE NORTH. SEAS SHOULD BUILD TO A VERY CHOPPY 4-6 FT WITH 7-FOOT
SEAS POSSIBLE WITHIN 20 MILES OF THE COAST NEAR CAPE FEAR.
SHORT TERM /FRIDAY THROUGH SATURDAY NIGHT/...
AS OF 2 PM THURSDAY...THE GALE WILL LIKELY PERSIST INTO THE FIRST
FEW HOURS OF FRI...WITH A PERIOD OF SMALL CRAFT ADVISORY CONDITIONS
EXPECTED THEREAFTER. LOW PRESSURE WILL HAVE MOVED WELL AWAY FROM THE
AREA BY FRI MORNING...INTENSIFYING OFF THE SE NEW ENGLAND COAST. AT
THE SAME TIME...STRONG HIGH PRESSURE WILL BE CENTERED ACROSS THE
OHIO AND TENNESSEE VALLEYS. THE COMBINATION OF THESE TWO FEATURES
WILL CREATE A RATHER TIGHT PRESSURE GRADIENT ACROSS THE WATERS. WIND
SPEEDS WILL BE ON A STEADY DOWNWARD TREND DURING THE DAY ON FRI...
VEERING FROM N TO NE BY FRI EVE AND REMAINING FROM THE NNE OR NE
INTO SAT. WIND SPEEDS WILL CONTINUE TO DIMINISH WITH THE APPROACH OF
THE CENTER OF HIGH PRESSURE. WINDS WILL BECOME MORE WESTERLY SAT
NIGHT AS ANOTHER COLD FRONT APPROACHES FROM THE NW. SEAS WILL BE IN
THE PROCESS OF PEAKING FRI MORNING...IN THE RANGE OF 6 TO 9 FT WITH
PERHAPS 10 FT AT THE FRYING PAN SHOALS BUOY. WAVE HEIGHTS WILL
STEADILY SUBSIDE FRI AFTERNOON AND NIGHT WITH SEAS COMMONLY 2 TO 3
FT SAT AND SAT NIGHT.
LONG TERM /SUNDAY THROUGH TUESDAY/...
AS OF 2 PM THURSDAY...OFFSHORE/WESTERLY WINDS ON SUNDAY WILL GET
VEERED ABOUT ABOUT A COMPASS POINT TO NW ASSOC WITH THE APPROACH OF
A COLD FRONT. A FURTHER TURN TO THE N LATER AT NIGHT WILL FOLLOW
FROPA BUT ANY INCREASE IN WIND SPEED AND THUS SEAS WILL BE MINIMAL.
THE WHOLE PROCESS IS THEN REPEATED BY THE APPROACH AND PASSAGE OF A
MORE VIGOROUS COLD FRONT MONDAY NIGHT. THIS BOUNDARY AND THE ENSUING
COLD SURGE COULD PUSH WIND AND/OR SEAS UP INTO SCEC REALM OR
POSSIBLY EVEN A SHORT LIVED ADVISORY.
&&
.ILM WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
NC...NONE.
MARINE...GALE WARNING UNTIL 9 AM EST THIS MORNING FOR AMZ250-252-254-
256.
&&
$$
SYNOPSIS...SHK/REK
NEAR TERM...REK/SHK
SHORT TERM...RJD
LONG TERM...MBB
AVIATION...SGL
MARINE...REK/RJD/MBB
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
1136 PM EST THU JAN 17 2013
.SYNOPSIS...
AN INTENSE AND QUICK MOVING AREA OF LOW PRESSURE WILL BRING
WIND...RAIN AND A RETURN TO CHILLY TEMPERATURES TONIGHT. THE
WINTER CHILL WILL PERSIST INTO THE WEEKEND AND THEN PERIODICALLY
BE REINFORCED BY SUCCESSIVE...DRY COLD FRONTS THROUGH MUCH OF
NEXT WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 1130 PM THURSDAY...BASED ON MULTIPLE REPORTS RELAYED THROUGH
TV METEOROLOGISTS OF SNOW MIXING WITH THE RAIN FARTHER SOUTH THAN
ASOS/AWOS REPORTS HAD INDICATED...I HAVE UPDATED THE FORECAST FOR
THE NEXT 3-5 HOURS TO INCLUDE MIXED PRECIP TYPES AS FAR SOUTH AS
DARLINGTON...DILLON...THE COLUMBUS/BLADEN COUNTY LINE...AND BURGAW.
THE LATEST SEVERAL RUC MODEL RUNS SHOW FREEZING LEVELS SHOULD BE
FALLING BELOW 2000 FT AGL SHORTLY IN THE BENNETTSVILLE AND LUMBERTON
AREAS WHICH MAY SUPPORT MORE SNOW MAKING IT TO THE SURFACE. MY
THOUGHTS STILL HAVE NOT CHANGED WITH RESPECT TO THE VERY LOW
LIKELIHOOD OF ANY ACCUMULATIONS REGARDLESS OF HOW MUCH SNOW MIXES
IN. PREVIOUS DISCUSSION FROM 1000 PM FOLLOWS...
THE COLD FRONT IS NOW WELL OFFSHORE. THE BAND OF HEAVY RAINFALL AND
EMBEDDED CONVECTION WITHIN THE ENHANCED ZONE OF ASCENT IS OFFSHORE
TOO. ATTENTION NOW TURNS TO THE UPPER LEVEL LOW CURRENTLY OVER
UPSTATE SOUTH CAROLINA. THIS SWIRLING BALL OF COLD AIR ALOFT IS
FORECAST BY ALL MODEL GUIDANCE TO MOVE NORTHEASTWARD TO THE SOUTHERN
CHESAPEAKE BAY BY 3-5 AM. STEEP LAPSE RATES ALOFT AND DEEP MOISTURE
ASSOCIATED WITH THIS LOW ARE PRODUCING WIDESPREAD LIGHT
PRECIPITATION EXTENDING FROM UPSTATE SOUTH CAROLINA ACROSS THE
WESTERN TWO-THIRDS OF NORTH CAROLINA. UNDERNEATH THIS UPPER
SYSTEM...COLD AIR BEING PULLED SOUTH BEHIND THE DEPARTING SURFACE
LOW HAS CHANGED RAIN OVER TO SNOW ALONG AND NORTH OF A LINE FROM
JUST NORTH OF CHARLOTTE TO ASHEBORO TO RALEIGH. WHILE THE CHANCES
FOR MEASURABLE SNOW HAVE NEVER BEEN GOOD IN OUR FORECAST
AREA...THERE REMAINS A SMALL POTENTIAL THAT THE RAIN COULD END MIXED
WITH SNOW ACROSS BENNETTSVILLE...LUMBERTON AND ELIZABETHTOWN AFTER
MIDNIGHT. NO ACCUMULATIONS ARE EXPECTED DUE TO ABOVE-FREEZING AIR
TEMPERATURES AND WELL-ABOVE FREEZING GROUND TEMPERATURES.
ALSO...I SPOKE TO A REPRESENTATIVE WITH THE EMERGENCY MANAGEMENT
AGENCY IN COLUMBUS COUNTY WHO REPORTED FAIRLY WIDESPREAD AND
SUBSTANTIAL DAMAGE FROM THE LINE OF SHOWERS THAT MOVED THROUGH THERE
AROUND 645 PM. WE WILL BE SENDING A STORM SURVEY TEAM OUT TO THE
CHADBOURN COMMUNITY IN WESTERN COLUMBUS COUNTY TOMORROW MORNING TO
SURVEY AND CLASSIFY THE DAMAGE THERE.
&&
.SHORT TERM /FRIDAY THROUGH SATURDAY NIGHT/...
AS OF 2 PM THURSDAY...WINTER IS BACK. IT WILL BE A CHILLY AND
BRISK START TO THE DAY FRI AS THE PRESSURE GRADIENT WILL REMAIN
RATHER TIGHT BETWEEN STRONG HIGH PRESSURE ACROSS THE OHIO AND
TENNESSEE VALLEYS AND LOW PRESSURE INTENSIFYING SE OF NEW ENGLAND.
THE GRADIENT WILL SLACKEN THROUGH THE AFTERNOON AND WIND
GUSTS...UP TO 25 TO 30 MPH...WILL DIMINISH. CHILLY TEMPS FRI
MORNING...ESPECIALLY IN COMPARISON TO RECENT DAYS...COUPLED WITH
THE WIND...WILL MAKE IT FEEL AS IF IT WERE IN THE MID 20S TO LOWER
30S. EVEN WITH BRIGHT SUNSHINE...TEMPS ARE NOT EXPECTED TO RISE
QUICKLY AS 850 MB TEMPS WILL START THE DAY JUST BELOW ZERO DEG.
PREVIOUS THINKING HAS NOT CHANGED AND WILL FORECAST HIGHS BELOW 50
DEGREES IN MOST PLACES...WITH MID 40S MOST COMMON. GOOD
RADIATIONAL COOLING IS EXPECTED FRI NIGHT AS HIGH PRESSURE REACHES
THE AREA. CLEAR SKIES AND VIRTUALLY CALM WIND WILL ALLOW EVE TEMPS
TO QUICKLY DROP AS DEWPOINTS DURING THIS TIME WILL BE WELL DOWN IN
THE 20S. OVERNIGHT LOWS ARE EXPECTED TO REACH THE MID AND UPPER
20S WITH SOME LOWER 20S WHERE RADIATIONAL COOLING MAXIMIZES
LONGEST.
CHILLY SURFACE HIGH PRESSURE WILL STILL BE IN PLACE ON SAT...BUT THE
WESTWARD EXTENT OF THE RIDGE WILL BEGIN TO BREAK DOWN DURING THE
AFTERNOON. SOME WEAK RETURN OF MILDER AIR AHEAD OF THE LEADING EDGE
OF THE NEXT COLD SURGE IS EXPECTED BY SAT AFTERNOON. THEREFORE...
THE SECOND HALF OF THE PERIOD SHOULD NOT BE AS CHILLY AND CLOSER TO
VALUES MORE TYPICAL OF MID JAN. WILL FORECAST HIGHS IN THE LOWER TO
MID 50S SAT. DEWPOINTS WILL BE CLIMBING THROUGH THE DAY SAT AND WITH
NIGHTFALL...TEMPS WILL NOT BE ABLE TO FALL AS RAPIDLY OR AS FAR AS
FRI NIGHT. DO NOT SEE A REASON TO STRAY TOO FAR FROM MODEL CONSENSUS
WHICH BRINGS LOWS TO THE MID AND UPPER 30S OVERNIGHT SAT.
&&
.LONG TERM /SUNDAY THROUGH THURSDAY/...
AS OF 2 PM THURSDAY...THE LONG TERM APPEARS TO BE ENTIRELY RAIN-FREE
AND INCREASINGLY COLD. SUNDAY WILL BE THE ONE MILD DAY AHEAD OF THE
FIRST SHOT OF COLDER AIR SLATED TO ARRIVE LATE IN THE DAY OR AT
NIGHT. THIS FIRST BOUNDARY WILL BE FAIRLY WEAK LEADING TO
TEMPERATURES ONLY A FEW DEGREES SHY OF CLIMO ON MONDAY...EVEN THOUGH
SOME 8 DEGREES COLDER THAN SUNDAY. DEEPENING MID LEVEL TROUGHINESS
AROUND HUDSON BAY VORTEX SENDS MUCH STRONGER SHOT OF COLD AIR
ADVECTION INTO THE SOUTHEAST MONDAY NIGHT. THERE IS STILL SOME
QUESTION AS TO THE ARCTIC CONTENT OF THE AIRMASS THAT FOLLOWS. THE
GFS FOR EXAMPLE HAS 850MB TEMPS RANGING FROM 0 TO -4C SOUTH TO NORTH
ACROSS THE REGION 00Z WED WHEREAS THE ECMWF (FROM 00Z) HAS -6 TO
-12C. THE CANADIAN IS CLOSER IN CAMP TO THE ECWMF IN SHOWING TRUE
ARCTIC AIR INVADING THE SOUTHEAST ALTHOUGH ITS PROGRESS IS SLIGHTLY
HELD UP BY A CLIPPER TYPE OF WAVE THAT MAY OR MAY NOT COME TO PASS.
CURRENT FORECAST WEIGHTED TOWARDS THE COLDER CONSENSUS.
&&
.AVIATION /00Z FRIDAY THROUGH TUESDAY/...
AS OF 00Z...PERIODS OF MVFR AND IFR WILL CONTINUE OVERNIGHT INTO THE
EARLY MORNING HOURS DUE TO REDUCED VISIBILITIES REGARDING PATCHY FOG
AND HEAVIER DOWNPOURS EARLY ON...FOLLOWED BY LOWERED CIGS. AFTER
DAYBREAK...VFR WILL PREVAIL AND CONTINUE THROUGH THE REMAINDER OF
THE VALID PERIOD.
CURRENT RADAR DEPICTS RAINFALL ACROSS THE ENTIRE AREA WITH QUITE THE
SCENARIO WITH A N-S WIND-DRIVEN LINE OF STORMS IN ASSOCIATION WITH A
LOW PRESSURE SYSTEM JUST ALONG THE COLD FRONT. AS A RESULT THERE ARE
A VARIETY OF WIND DIRECTIONS ACROSS THE AREA WITH WESTERLY WINDS AT
KFLO/KMYR/KCRE...AND EAST-NORTHEASTERLY WINDS AT KLBT/KILM. AS THIS
LINE CONTINUES TO PROPAGATE EAST NORTH-EAST AND TAPER OFF OVER THE
NEXT FEW HOURS...ALL WINDS WILL BECOME WESTERLY AOB 15 KTS WITH
GUSTS UP TO 25 KTS OVERNIGHT. AFTER MIDNIGHT...WIND DIRECTION WILL
CONTINUE TO VEER...BECOMING NORTHERLY AOB 15 KTS GUSTS 18-25 KTS
INTO THE MORNING HOURS. ANY RESIDUAL LOWERED CIGS FROM OVERNIGHT
WILL QUICKLY IMPROVE BY MORNING AS THE COLD FRONT PUSHES OUT OF THE
AREA. VFR WILL PREVAIL FOR THE REMAINDER OF THE PERIOD.
NORTH-NORTHEAST WINDS WILL CONTINUE THROUGHOUT THE DAY ON
FRIDAY...WITH GUSTS SUBSIDING INTO THE EARLY EVENING HOURS.
EXTENDED OUTLOOK...VFR THROUGH THE EXTENDED.
&&
.MARINE...
NEAR TERM /THROUGH TONIGHT/...
AS OF 1000 PM THURSDAY...THE ONLY SIGNIFICANT CHANGE TO THE FORECAST
WAS TO RAISE SEA HEIGHTS BY 1-2 FEET BASED ON CURRENTLY REPORTED
WAVE OBSERVATIONS FROM THE FRYING PAN SHOALS BUOY...THE NEARSHORE
WRIGHTSVILLE BEACH BUOY...AND THE OCEAN CREST PIER WAVE GAUGE. WITH
THE COLD FRONT AND ATTENDANT LOW PRESSURE AREA NOW OFFSHORE WINDS
WILL BECOME NORTHERLY OVERNIGHT WITH GALE FORCE GUSTS REMAINING
POSSIBLE. PREVIOUS DISCUSSION FROM 630 PM FOLLOWS...
A COLD FRONT HAS SLID IN FROM THE NORTH AND LIES BETWEEN
WRIGHTSVILLE BEACH AND CAROLINA BEACH ALONG THE NORTH CAROLINA
COASTLINE. NORTHEAST WINDS NORTH OF THE BOUNDARY CONTRAST WITH SOUTH
WINDS ELSEWHERE. ANOTHER PORTION OF THE COLD FRONT IS QUICKLY
OVERTAKING FROM THE WEST...DRIVEN BY STRONG SURFACE LOW PRESSURE NOW
JUST NORTH OF MYRTLE BEACH. THIS LOW AND FRONT WILL SWEEP ACROSS THE
ENTIRE FORECAST AREA IN THE NEXT COUPLE OF HOURS...FOLLOWED BY GUSTY
WESTERLY WINDS THAT SHOULD TURN MORE NORTHERLY WITH TIME OVERNIGHT.
A GALE WARNING REMAINS IN EFFECT MORE FOR GUSTS THAN FOR SUSTAINED
WIND SPEEDS. THE STRONGEST WINDS ARE EXPECTED THIS EVENING WITH
CONVECTIVE SHOWERS ALONG THE FRONT...AND THEN AGAIN AFTER MIDNIGHT
AS THE LOW MOVES OFFSHORE AND COLD AIR POURS INTO THE REGION FROM
THE NORTH. SEAS SHOULD BUILD TO A VERY CHOPPY 4-6 FT WITH 7-FOOT
SEAS POSSIBLE WITHIN 20 MILES OF THE COAST NEAR CAPE FEAR.
SHORT TERM /FRIDAY THROUGH SATURDAY NIGHT/...
AS OF 2 PM THURSDAY...THE GALE WILL LIKELY PERSIST INTO THE FIRST
FEW HOURS OF FRI...WITH A PERIOD OF SMALL CRAFT ADVISORY CONDITIONS
EXPECTED THEREAFTER. LOW PRESSURE WILL HAVE MOVED WELL AWAY FROM THE
AREA BY FRI MORNING...INTENSIFYING OFF THE SE NEW ENGLAND COAST. AT
THE SAME TIME...STRONG HIGH PRESSURE WILL BE CENTERED ACROSS THE
OHIO AND TENNESSEE VALLEYS. THE COMBINATION OF THESE TWO FEATURES
WILL CREATE A RATHER TIGHT PRESSURE GRADIENT ACROSS THE WATERS. WIND
SPEEDS WILL BE ON A STEADY DOWNWARD TREND DURING THE DAY ON FRI...
VEERING FROM N TO NE BY FRI EVE AND REMAINING FROM THE NNE OR NE
INTO SAT. WIND SPEEDS WILL CONTINUE TO DIMINISH WITH THE APPROACH OF
THE CENTER OF HIGH PRESSURE. WINDS WILL BECOME MORE WESTERLY SAT
NIGHT AS ANOTHER COLD FRONT APPROACHES FROM THE NW. SEAS WILL BE IN
THE PROCESS OF PEAKING FRI MORNING...IN THE RANGE OF 6 TO 9 FT WITH
PERHAPS 10 FT AT THE FRYING PAN SHOALS BUOY. WAVE HEIGHTS WILL
STEADILY SUBSIDE FRI AFTERNOON AND NIGHT WITH SEAS COMMONLY 2 TO 3
FT SAT AND SAT NIGHT.
LONG TERM /SUNDAY THROUGH TUESDAY/...
AS OF 2 PM THURSDAY...OFFSHORE/WESTERLY WINDS ON SUNDAY WILL GET
VEERED ABOUT ABOUT A COMPASS POINT TO NW ASSOC WITH THE APPROACH OF
A COLD FRONT. A FURTHER TURN TO THE N LATER AT NIGHT WILL FOLLOW
FROPA BUT ANY INCREASE IN WIND SPEED AND THUS SEAS WILL BE MINIMAL.
THE WHOLE PROCESS IS THEN REPEATED BY THE APPROACH AND PASSAGE OF A
MORE VIGOROUS COLD FRONT MONDAY NIGHT. THIS BOUNDARY AND THE ENSUING
COLD SURGE COULD PUSH WIND AND/OR SEAS UP INTO SCEC REALM OR
POSSIBLY EVEN A SHORT LIVED ADVISORY.
&&
.ILM WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
NC...NONE.
MARINE...GALE WARNING UNTIL 9 AM EST FRIDAY FOR AMZ250-252-254-256.
&&
$$
NEAR TERM...TRA
SHORT TERM...RJD
LONG TERM...MBB
AVIATION...SGL
AREA FORECAST DISCUSSION FOR SOUTHEAST SD/SOUTHWEST MN/NORTHWEST IA
NWS SIOUX FALLS SD
1030 PM CST THU JAN 17 2013
.DISCUSSION.../ISSUED AT 845 PM CST/
THE WARM FRONT IS PRESENTLY SITUATED THROUGH OUR SOUTH CENTRAL SOUTH
DAKOTA ZONES LATE THIS EVENING. AS EXPECTED MID CLOUDS ALSO
STREAMING OVERHEAD...WITH BROKEN STRATUS COVERING A GOOD BIT OF OUR
NORTH AND EAST EARLIER IN THE EVENING NOW MOSTLY DISSIPATING EXCEPT
FOR SOME AREAS OF NORTHWESTERN IOWA. ALL MODELS ARE OVERDOING THE
EXTENT OF STRATUS THIS EVENING...BUT ALL POINT TOWARD ANY EXISTING
LOW CLOUDS PULLING OFF TO THE NORTHEAST OVERNIGHT AS THE LOW LEVEL
FLOW TURNS SOUTH/SOUTHWESTERLY. OBS INDICATING SOME FOG DEVELOPING
JUST TO OUR SOUTH...THROUGH EASTERN NEBRASKA...WITH A FEW LOWERING
VISIBILITIES OVER NORTHWESTERN IOWA ALSO...SO PATCHY FOG REMAINS
APPROPRIATE IN THE FORECAST FOR PARTS OF THE AREA TONIGHT.
TEMPERATURES ARE ON TRACK FOR LOWS MAINLY IN THE 20S...POSSIBLY
RISING A BIT LATER IN THE NIGHT AS WINDS PICK UP AND CLOUDS CONTINUE
TO STREAM ACROSS THE REGION. GOING FORECAST COVERS THE ABOVE
MENTIONED ELEMENTS PRETTY WELL...WITH ONLY MINOR UPDATES FOR REAL
TIME TRENDS.
&&
.AVIATION.../FOR THE 06Z TAF ISSUANCE/
OCCASIONAL IFR CEILINGS AND VISIBILITIES WILL OCCUR EAST OF I29
THROUGH 12Z FRIDAY AND THEN VFR 12Z THROUGH 06Z. WEST OF I29...VFR
CONDITIONS CAN BE EXPECTED THROUGH 06Z SATURDAY.
&&
.PREV DISCUSSION.../ISSUED AT 311 PM CST/
WARM FRONT LIFTS NORTH TONIGHT GIVING WAY TO A MILD AND MOSTLY SUNNY
FRIDAY ACROSS THE AREA. FORECAST TONIGHT A BIT TRICKY WITH POTENTIAL
STRATUS ISSUES. MID LEVEL CLOUDS WILL CONTINUE TO STREAM ACROSS OUR
NORTH THROUGH THE NIGHT ASSOCIATED WITH MID LEVEL FRONTAL BOUNDARY.
HOWEVER THINK THE CWA WILL REMAIN DRY...OTHER THAN MAYBE AN ISOLATED
FLURRY ACROSS SOUTHWEST MINNESOTA. AREA OF STRATUS FROM SOUTH OF
SIOUX FALLS INTO EASTERN NEBRASKA CONTINUES TO DISSIPATE UNDER
DAYTIME HEATING. HOWEVER...CURRENT THINKING...BACKED BY THE RAP AND
NAM...IS THAT THIS AREA WILL REFORM AND EXPAND THIS EVENING INTO
TONIGHT. WITH SOUTHERLY BOUNDARY LAYER FLOW THIS WILL THEN EXPAND
AND COULD COVER MUCH OF THE CWA FOR A PERIOD TONIGHT. DRIER BOUNDARY
LAYER MOVING IN FROM THE SOUTHWEST WILL ALLOW THE STRATUS TO CLEAR
FROM SOUTHWEST TO NORTHEAST THROUGH THE NIGHT. COULD BE AREAS OF FOG
AS WELL. BEST CHANCE OF STAYING CLEAR THROUGH THE NIGHT WILL BE WEST
OF SIOUX CITY TO YANKTON UP TOWARDS GREGORY. LOW LEVEL JET INCREASES
TONIGHT...WHICH SHOULD KEEP A SOUTHERLY BREEZE GOING. THE BREEZE
COMBINED WITH POTENTIAL CLOUDS SHOULD KEEP LOWS ON THE WARM SIDE OF
GUIDANCE. GENERALLY AROUND 20 SOUTHWEST MINNESOTA TO LOW AND MID 20S
ELSEWHERE. LOWS WILL PROBABLY BE IN THE EVENING...WITH STEADY OR
RISING TEMPERATURES OVERNIGHT.
ANY STRATUS SHOULD EXIT THE CWA BY AROUND 12Z. COULD BE SOME CIRRUS
OVERHEAD DURING THE DAY...BUT OVERALL EXPECTING A MOSTLY SUNNY DAY.
KEPT HIGHS CLOSE TO THE ECMWF AND ECMWF MOS...AS THEY PERFORMED BEST
ON WEDNESDAY. LOOKING AT LOW AND MID 40S NORTH TO THE LOW AND MID
50S CLOSER TO THE MISSOURI RIVER. WITH 925MB TEMPERATURES
APPROACHING 10C IN OUR SOUTHWEST...WOULD NOT BE SURPRISED IF
SOMEPLACE IN NORTH CENTRAL NEBRASKA...OR ADJACENT AREAS OF GREGORY
AND CHARLES MIX COUNTIES COME CLOSE TO 60. /CHENARD
MAJOR PATTERN CHANGE EXPECTED TO BEGIN ON SATURDAY AS AN ARCTIC
BLAST DROPS SOUTHWARD INTO THE NORTHERN PLAINS. COLD FRONT SLATED TO
PUSH THROUGH THE FORECAST AREA DURING THE DAY...AND THE BIG QUESTION
IS HOW QUICKLY IT WILL ARRIVE. LARGE TEMPERATURE DISCREPANCIES
BETWEEN MODELS FOR SATURDAY HIGHS WITH A STAGGERING NEARLY 30 DEGREE
DIFFERENCE BETWEEN THE WARMEST AND COLDEST MODELS IN SIOUX FALLS.
THE GFS AND NAM ARE THE FASTEST WITH PULLING THE COLDER AIR INTO THE
FORECAST AREA WHILE THE ECMWF AND GEM PAINT A MUCH SLOWER
PROGRESSION AND DEPICT A MILD DAY ACROSS THE CWA. HAVE OPTED FOR A
MIDDLE GROUND SOLUTION WITH MIXING KEEPING TEMPERATURES ON THE
MILDER SIDE. EXPECT THE MISSOURI VALLEY TO REACH NEAR 40 RANGING TO
AROUND 30 AT OUR NORTHERN BORDER.
FRONTAL PASSAGE IS EXPECTED TO BE DRY...BUT STRONG NORTHWEST WINDS
IN ITS WAKE WILL PRODUCE SOME BRUTAL WIND CHILLS. WITH 925MB WINDS
UP AROUND 50 KT AND STRONG COLD AIR ADVECTION...WOULD NOT BE
SURPRISED TO SEE ADVISORY LEVEL WINDS. COLD AIR WILL QUICKLY DROP
SOUTH LATE EVENING INTO THE OVERNIGHT AND LOWS SATURDAY NIGHT WILL
BE IN THE SINGLE DIGITS ABOVE AND BELOW ZERO. WINDS WILL DECREASE ON
SUNDAY AS SURFACE HIGH PRESSURE QUICKLY SHUNTS SOUTHEAST OF THE
REGION...BUT DO NOT EXPECT MUCH RECOVERY OF TEMPERATURES. HIGHS WILL
ONLY BE IN THE SINGLE DIGITS AND TEENS FOR THE MAJORITY OF THE CWA.
A QUICK SHOT OF LIGHT SNOW WILL MOVE SOUTHEAST DURING THE DAY AHEAD
OF A REINFORCING SHOT OF COLD AIR. SNOW WOULD LIKELY BE BRIEF WITH
NOT MUCH MOISTURE TO WORK WITH...HOWEVER THE COLD TEMPERATURES
SHOULD PRODUCE UP TO AN INCH OF FLUFFY SNOW. NORTHERLY WINDS WILL
PICK UP ONCE AGAIN BEHIND THE FRONT AND WOULD DRIFT WHATEVER SNOW
FALLS ON SUNDAY. SUNDAY NIGHT WILL SEE SOME OF THE COLDEST
TEMPERATURES OF THE SEASON SO FAR WITH THE NORTHERN HALF DROPPING
INTO THE TEENS BELOW ZERO. FRIGID TEMPERATURES WILL CONTINUE INTO
MONDAY WITH HIGHS NEAR ZERO IN OUR NORTHEAST.
MODELS KEEP THE LARGE UPPER RIDGE OVER THE INTERMOUNTAIN WEST IN
PLACE INTO TUESDAY...WHICH LEAVES THE FORECAST AREA UNDER COOL
NORTHWEST FLOW. MODELS BRING A WEAK WAVE THROUGH THE FLOW AROUND THE
MONDAY NIGHT TO TUESDAY TIME FRAME...HOWEVER NOT A LOT OF CONFIDENCE
THAT THE CWA WILL SEE MUCH IMPACT. WILL LEAVE THE SLIGHT CHANCES
THAT THE LATEST ALLBLEND PRODUCED FOR NOW. WARMER WEATHER MAY RETURN
ON WEDNESDAY AND THURSDAY WITH THE RIDGE ADVANCING EASTWARD.
&&
.FSD WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
MN...NONE.
IA...NONE.
NE...NONE.
&&
$$
YOU CAN SEE AN ILLUSTRATED VERSION OF THE FORECAST DISCUSSION AT
WWW.WEATHER.GOV/SEATTLE/GAFD/LATEST_WEBAFD.HTML.
AREA FORECAST DISCUSSION...UPDATED
NWS GREEN BAY WI
757 PM CST SAT JAN 19 2013
.UPDATE...GOING TO REPLACE THE WIND CHILL ADVISORY FOR VILAS
COUNTY WITH A WINTER WX ADVISORY AS A CATCH ALL FOR THE
SNOW...WIND...AND LOW WIND CHILLS LATER TONIGHT. VSBYS STILL LOW
BACK TO THE NW OF THERE AT IWD/ASX...AND TRAJ BECOMING MORE
FAVORABLE FOR ADDITIONAL LAKE-EFFECT. SUBSIDENCE/DRIER AIR
ARRIVING OVER THE LAKE WL EVENTUALLY SHUT THINGS DOWN. BUT GIVEN
THE SNOW THATS ALREADY FALLEN...THE WIND TO BLOW IT AROUND...AND
THE PLUMMETING TEMPS LIKELY RESULTING IN ICY ROADWAYS...IT SEEMS
THE MAIN HAZARD THE REST OF THE NGT WL BE MORE SN/BLSN RELATED
RATHER THAN WIND CHILL RELATED.
THE REST OF THE N WL HAVE TRAVEL PROBLEMS TOO...BUT ADDITIONAL
SNOWFALL WL BE MUCH LIGHTER AS LAKE-EFFECT WON/T BE A MAJOR FACTOR
AS IN VILAS.
THE OTHER HEADLINES SEEM TO BE ON TRACK...SO AT THIS POINT DON/T
PLAN ON MAKING ANY CHGS UNTIL WE GET CLOSER TO THE SCHEDULED
EXPIRATION OF THE WIND ADVSIORY OVER THE WRN PART OF THE AREA LATE
THIS EVENING.
SKOWRONSKI
&&
.PREV DISCUSSION...ISSUED AT 600 PM CST SAT JAN 19 2013...
UPDATE...SPOTTER REPORT FROM ONEIDA COUNTY INDICATING VERY POOR
TRAVEL CONDITIONS. VSBY DOWN TO NEAR ZERO IN SN/BLSN. PLUS...TEMPS
PLUNGING BLO FZG WL LIKELY CAUSE ROADS TO ICE OVER AS WELL. THE
LOW VSBYS SHOULD BE RELATIVELY BRIEF...BUT THEIR SUDDEN ONSET WL
PROBABLY STILL CAUSE SIG PROBLEMS FOR ANYONE OUT ON THE ROADS.
SENT UPDATED SPS TO HIGHLIGHT THE SITN.
STILL NOT CERTAIN JUST HOW FAR S AND E THE POOR CONDITIONS WL
REACH. RADAR SHOWS A DEFINITE INCR IN SHSN ACTIVITY OVER CENTRAL
AND INTO E-C WI. BUT WE WERE WARM ENOUGH HERE AT THE OFFICE TO GET
SOME RAIN AS THE PCPN TYPE. ALTHOUGH CONDITIONS PROBABLY WON/T GET
QUITE AS BAD AS IN THE NW PART OF THE FCST AREA BECAUSE THE TEMP
DROP TO BLO FZG WL LAG A LITTLE FARTHER BEHIND THE PCPN...COULD
STILL GET SOME NASTY TRAVEL CONDITIONS AT TIMES.
UPDATED PRODUCT SUITE ALREADY SENT...THOUGH PREV FCST ALREADY HAD
THE GIST OF THE SITN PRETTY WELL SPELLED OUT.
SKOWRONSKI
DISCUSSION ISSUED AT 443 PM CST SAT JAN 19 2013...
SHORT TERM...TONIGHT AND SUNDAY.
LATEST RUC ANALYSIS AND SATELLITE/RADAR IMAGERY SHOW A STRONG
SHORTWAVE DIVING SE OVER NORTHERN MINNESOTA...WHICH IS DRIVING A
SURFACE LOW OVER WESTERN LAKE SUPERIOR. ARCTIC COLD FRONT EXTENDS
WESTWARD FROM THIS LOW OVER CENTRAL MINNESOTA AND NORTHERN SOUTH
DAKOTA. RETURNS ON RADAR OVER WESTERN WISCONSIN MAY NOT BE HITTING
THE GROUND...BUT THERE IS SCATTERED SNOW SHOWERS OCCURRING ALONG THE
ARCTIC FRONT AND JUST AHEAD OF THE SHORTWAVE...WHICH ARE DROPPING
VISIBILITIES TO AROUND A MILE AT TIMES. WINDS ARE ALSO RAPIDLY
INCREASING BEHIND THE FRONT...WITH SOME WIDELY SCATTERED REPORTS
JUST HIGHER THAN 40 KTS. TEMPERATURES BEHIND THE FRONT ARE FALLING
QUICKLY INTO THE SINGLE DIGITS ABOVE ZERO...WHILE READINGS ARE IN
THE UPPER 30S TO LOWER 40S ACROSS NORTHERN WISCONSIN. WITH THE
PASSAGE OF THE ARCTIC FRONT THIS EVENING...TEMPERATURE AND WIND
HEADLINES ARE THE MAIN FORECAST CONCERNS.
TONIGHT...THE STRONG SHORTWAVE WILL PUSH THE ARCTIC COLD FRONT
RAPIDLY SOUTHEAST ACROSS NORTH-CENTRAL WISCONSIN LATER THIS
AFTERNOON...AND NORTHEAST WISCONSIN EARLY THIS EVENING. DESPITE
STRONG MID AND UPPER LEVEL FORCING IN THE FORM OF -DIVQ AND
DIVERGENCE AHEAD OF THE WAVE...MID-LEVELS STRUGGLE TO SATURATE. SO
THINK WILL SEE NOT MUCH MORE THAN A SCT LINE OF SNOW SHOWERS JUST
AHEAD OF THE SHORTWAVE...WHICH WILL PROVIDE A BRIEF BURST OF SNOW
AND REDUCE VISIBILITIES...BUT NOT MUCH IN THE WAY OF ACCUMS. SO
WILL KEEP POPS IN THE LOW CHANCE RANGE OVER NE WISCONSIN FOR EARLY
THIS EVENING WITH THE FRONTAL PASSAGE. CLOUDS EXTEND NORTH ACROSS
MINNESOTA TO THE CANADIAN BORDER WHERE SNOW SHOWERS CONTINUE TO FALL
UNDER A LOW OVERCAST. SO THINK SNOW SHOWERS WILL FALL OVER
NORTH-CENTRAL WISCONSIN FOR MUCH OF THE EVENING. BEHIND THE FRONT
BY LATE IN THE EVENING...LOW LEVEL WINDS WILL SHIFT TO THE NORTHWEST
WITH GOOD TRAJECTORIES FOR LAKE EFFECT SNOW ACCUMULATIONS.
HOWEVER...850MB TEMPS WILL BE PLUMMETING INTO THE LOWER 20S BELOW
ZERO WHICH IS GETTING TOO COLD FOR GOOD DENDRITIC SNOW GROWTH. AS A
RESULT...FLAKES WILL BE SMALL AND ACCUMS SHOULD BE HELD IN
CHECK...AND WILL CONTINUE TO GO WITH 1-3 INCH AMOUNTS TONIGHT IN THE
SNOW BELT OF N-C WISCONSIN. LITTLE TO NO ACCUM ELSEWHERE.
BIGGER IMPACTS WILL LIKELY BE WIND RELATED. STRONG DESCENT
IMMEDIATELY BEHIND THE FRONT IN A REGION OF STRONG COLD
ADVECTION...STEEPENING LOW LEVEL LAPSE RATES...AND GOOD ISALLABARIC
PUSH WILL CREATE STRONG GUSTY WEST TO NORTHWEST WINDS THAT SHOULD
APPROACH OR JUST EXCEED WIND ADVISORY CRITERIA LATE THIS AFTERNOON
AND THROUGH THE EVENING. STRONGEST WINDS IN THE MIXED LAYER OF
45-50KTS ARE PROGGED TO OCCUR OVER CENTRAL AND EAST-CENTRAL
WISCONSIN WHERE THE CURRENT WIND ADVISORY RESIDES...SO PLACEMENT OF
HEADLINES LOOK GOOD. THE GUSTY WINDS SEEM TO BE RUNNING AN HOUR OR
TWO LATE...AND WILL LIKELY HAVE TO WAIT UNTIL THE COLDER AIR ALOFT
ARRIVES TO STEEPEN THE LOW LEVEL LAPSE RATES FOR THE GUSTY WINDS TO
OCCUR...LIKELY IN THE 22-02Z TIME PERIOD. WILL KEEP HEADLINE TIMING
STATUS QUO. THE STRONG PRESSURE RISES SHIFT TO THE EAST BY
MIDNIGHT...AND WIND GUSTS SHOULD BE SUBSIDING BY THIS TIME. AS A
RESULT...STILL THINK THE EVENING OR MIDNIGHT CREW WILL BE ABLE TO
END WIND HEADLINES EARLY. THE COMBO OF GUSTY NW WINDS AND INCOMING
ARCTIC AIR WILL CREATE WIND CHILL READINGS OF 20-25 DEGREES BELOW
ZERO OVER CENTRAL AND NORTH-CENTRAL WISCONSIN LATE TONIGHT.
SUNDAY...ARCTIC AIR WILL CONTINUE TO POUR ACROSS THE REGION ON
SUNDAY. NORTHWEST WINDS WILL CONTINUE TO PRODUCE LAKE EFFECT SNOW
SHOWERS IN THE SNOW BELTS...BUT WINDS DO BACK A BIT SO SNOW SHOWERS
SHOULD BE GRADUALLY DIMINISHING OVER THE COURSE OF THE MORNING. AIR
WILL REMAIN TOO COLD FOR DENDRITIC SNOW GROWTH SO NOT EXPECTING MUCH
ACCUMS. OTHERWISE...STEEP LOW LEVEL LAPSE RATES AND FLOW OFF LAKE
SUPERIOR SHOULD KEEP SKIES PARTLY TO MOSTLY CLOUDY. TEMPS IN THE
SINGLE DIGITS TO LOWER TEENS.
LONG TERM...SUNDAY NIGHT THROUGH NEXT SATURDAY. DURATION OF THE
ARCTIC BLAST OF AIR THIS WEEK ALONG WITH LIKELY ADDITIONAL WIND
CHILL HEADLINES WILL BE THE PRIMARY ISSUE FOR THE FIRST HALF OF
THE NEW WEEK. ANOTHER CLIPPER SYSTEM IS PROGGED TO DROP INTO THE
REGION AROUND THURSDAY FOLLOWED WITH A REINFORCING BUT MILDER
AND PERHAPS BRIEFER SHOT OF ARCTIC AIR. SOME MDM RANGE MODELS ARE
INDICATING A MODERATING TREND LATER NEXT WEEKEND.
ADDITIONAL WIND CHILL HEADLINES WILL LIKELY BE POSTED LATER THIS
WEEKEND AS THE SATURDAY NIGHT HEADLINES EXPIRE. FORECAST TEMPS
SUGGEST THE COLDEST AIR ARRIVES LATER MONDAY WITH SOME CURRENT
VALUES APPROACHING WIND CHILL WARNING CRITERIA MONDAY NIGHT.
TYPICAL WITH THE VERY COLD PATTERNS...MODELS LIKELY OVERDOING THE
COVERAGE OF CLOUDS. WILL TONE DOWN CLOUDS OVER MOST LOCATIONS
EXCEPT FOR AREAS JUST DOWNSTREAM FROM LAKE SUPERIOR.
LAKE EFFECT SNOWS EXPECTED OVER FAR NORTH CENTRAL WISCONSIN WITH
THE COLD AIR INTRUSION. BUT APPEARS TO BE LIMITED AT THIS TIME
DUE TO THE DRY AIR MASS...FALLING INVERSION HEIGHTS...AND A BIT
TOO WESTERLY WIND DIRECTION.
TEMPS TO MODERATE TO NEAR SEASONAL LEVELS LATER THIS WEEK WITH A
CLIPPER SYSTEM DROPPING SOUTH INTO THE NORTHERN AND CENTRAL PLAINS
THURSDAY BEFORE PHASING WITH SOME SOUTHERN STREAM ENERGY THURSDAY
NIGHT. GFS IS INDICATING A POSSIBLE ADVISORY SNOW OVER THE SOUTH
HALF OR THIRD OF THE STATE THURSDAY NIGHT WITH THIS PHASED SYSTEM.
WILL GLANCE AT THE ECMWF THIS AFTERNOON TOO SEE IF A SIMILAR
TREND IN ORDER TO MAKE ANY ADJUSTMENTS...BUT GOING FORECAST THAT
FAR OUT REASONABLE.
&&
.AVIATION...FOR 00Z TAF ISSUANCE. ARCTIC FRONT SURGING SE ACRS THE
AREA. WL SEE A PERIOD OF STG WINDS AND SOME MVFR CIGS AND VSBYS
THIS EVENING. BRIEF IFR CONDITONS POSSIBLE. NOT REALLY THAT MUCH
SNOW TO BLOW ARND IN THE AREA...SO EXPECT CONDITIONS TO IMPROVE
BACK TO VFR BY LATE TNGT. THE EXCEPTION MAY BE IN THE FAR N /RHI/
WHERE CLDS OFF LAKE SUPERIOR WL CONT TO STREAM SE.
&&
.GRB WATCHES/WARNINGS/ADVISORIES...
WIND ADVISORY UNTIL 3 AM CST SUNDAY FOR WIZ038>040-048>050.
WIND ADVISORY UNTIL MIDNIGHT CST TONIGHT FOR WIZ030-031-035>037-
045.
WIND CHILL ADVISORY FROM MIDNIGHT TONIGHT TO 9 AM CST SUNDAY FOR
WIZ010-011-018-019-030-035-036.
WIND ADVISORY UNTIL 6 AM CST SUNDAY FOR WIZ022.
WINTER WEATHER ADVISORY UNTIL 9 AM CST SUNDAY FOR WIZ005.
&&
$$
AREA FORECAST DISCUSSION...UPDATED
NWS GREEN BAY WI
600 PM CST SAT JAN 19 2013
.UPDATE...SPOTTER REPORT FROM ONEIDA COUNTY INDICATING VERY POOR
TRAVEL CONDITIONS. VSBY DOWN TO NEAR ZERO IN SN/BLSN. PLUS...TEMPS
PLUNGING BLO FZG WL LIKELY CAUSE ROADS TO ICE OVER AS WELL. THE
LOW VSBYS SHOULD BE RELATIVELY BRIEF...BUT THEIR SUDDEN ONSET WL
PROBABLY STILL CAUSE SIG PROBLEMS FOR ANYONE OUT ON THE ROADS.
SENT UPDATED SPS TO HIGHLIGHT THE SITN.
STILL NOT CERTAIN JUST HOW FAR S AND E THE POOR CONDITIONS WL
REACH. RADAR SHOWS A DEFINITE INCR IN SHSN ACTIVITY OVER CENTRAL
AND INTO E-C WI. BUT WE WERE WARM ENOUGH HERE AT THE OFFICE TO GET
SOME RAIN AS THE PCPN TYPE. ALTHOUGH CONDITIONS PROBABLY WON/T GET
QUITE AS BAD AS IN THE NW PART OF THE FCST AREA BECAUSE THE TEMP
DROP TO BLO FZG WL LAG A LITTLE FARTHER BEHIND THE PCPN...COULD
STILL GET SOME NASTY TRAVEL CONDITIONS AT TIMES.
UPDATED PRODUCT SUITE ALREADY SENT...THOUGH PREV FCST ALREADY HAD
THE GIST OF THE SITN PRETTY WELL SPELLED OUT.
SKOWRONSKI
&&
.PREV DISCUSSION...ISSUED AT 443 PM CST SAT JAN 19 2013...
SHORT TERM...TONIGHT AND SUNDAY.
LATEST RUC ANALYSIS AND SATELLITE/RADAR IMAGERY SHOW A STRONG
SHORTWAVE DIVING SE OVER NORTHERN MINNESOTA...WHICH IS DRIVING A
SURFACE LOW OVER WESTERN LAKE SUPERIOR. ARCTIC COLD FRONT EXTENDS
WESTWARD FROM THIS LOW OVER CENTRAL MINNESOTA AND NORTHERN SOUTH
DAKOTA. RETURNS ON RADAR OVER WESTERN WISCONSIN MAY NOT BE HITTING
THE GROUND...BUT THERE IS SCATTERED SNOW SHOWERS OCCURRING ALONG THE
ARCTIC FRONT AND JUST AHEAD OF THE SHORTWAVE...WHICH ARE DROPPING
VISIBILITIES TO AROUND A MILE AT TIMES. WINDS ARE ALSO RAPIDLY
INCREASING BEHIND THE FRONT...WITH SOME WIDELY SCATTERED REPORTS
JUST HIGHER THAN 40 KTS. TEMPERATURES BEHIND THE FRONT ARE FALLING
QUICKLY INTO THE SINGLE DIGITS ABOVE ZERO...WHILE READINGS ARE IN
THE UPPER 30S TO LOWER 40S ACROSS NORTHERN WISCONSIN. WITH THE
PASSAGE OF THE ARCTIC FRONT THIS EVENING...TEMPERATURE AND WIND
HEADLINES ARE THE MAIN FORECAST CONCERNS.
TONIGHT...THE STRONG SHORTWAVE WILL PUSH THE ARCTIC COLD FRONT
RAPIDLY SOUTHEAST ACROSS NORTH-CENTRAL WISCONSIN LATER THIS
AFTERNOON...AND NORTHEAST WISCONSIN EARLY THIS EVENING. DESPITE
STRONG MID AND UPPER LEVEL FORCING IN THE FORM OF -DIVQ AND
DIVERGENCE AHEAD OF THE WAVE...MID-LEVELS STRUGGLE TO SATURATE. SO
THINK WILL SEE NOT MUCH MORE THAN A SCT LINE OF SNOW SHOWERS JUST
AHEAD OF THE SHORTWAVE...WHICH WILL PROVIDE A BRIEF BURST OF SNOW
AND REDUCE VISIBILITIES...BUT NOT MUCH IN THE WAY OF ACCUMS. SO
WILL KEEP POPS IN THE LOW CHANCE RANGE OVER NE WISCONSIN FOR EARLY
THIS EVENING WITH THE FRONTAL PASSAGE. CLOUDS EXTEND NORTH ACROSS
MINNESOTA TO THE CANADIAN BORDER WHERE SNOW SHOWERS CONTINUE TO FALL
UNDER A LOW OVERCAST. SO THINK SNOW SHOWERS WILL FALL OVER
NORTH-CENTRAL WISCONSIN FOR MUCH OF THE EVENING. BEHIND THE FRONT
BY LATE IN THE EVENING...LOW LEVEL WINDS WILL SHIFT TO THE NORTHWEST
WITH GOOD TRAJECTORIES FOR LAKE EFFECT SNOW ACCUMULATIONS.
HOWEVER...850MB TEMPS WILL BE PLUMMETING INTO THE LOWER 20S BELOW
ZERO WHICH IS GETTING TOO COLD FOR GOOD DENDRITIC SNOW GROWTH. AS A
RESULT...FLAKES WILL BE SMALL AND ACCUMS SHOULD BE HELD IN
CHECK...AND WILL CONTINUE TO GO WITH 1-3 INCH AMOUNTS TONIGHT IN THE
SNOW BELT OF N-C WISCONSIN. LITTLE TO NO ACCUM ELSEWHERE.
BIGGER IMPACTS WILL LIKELY BE WIND RELATED. STRONG DESCENT
IMMEDIATELY BEHIND THE FRONT IN A REGION OF STRONG COLD
ADVECTION...STEEPENING LOW LEVEL LAPSE RATES...AND GOOD ISALLABARIC
PUSH WILL CREATE STRONG GUSTY WEST TO NORTHWEST WINDS THAT SHOULD
APPROACH OR JUST EXCEED WIND ADVISORY CRITERIA LATE THIS AFTERNOON
AND THROUGH THE EVENING. STRONGEST WINDS IN THE MIXED LAYER OF
45-50KTS ARE PROGGED TO OCCUR OVER CENTRAL AND EAST-CENTRAL
WISCONSIN WHERE THE CURRENT WIND ADVISORY RESIDES...SO PLACEMENT OF
HEADLINES LOOK GOOD. THE GUSTY WINDS SEEM TO BE RUNNING AN HOUR OR
TWO LATE...AND WILL LIKELY HAVE TO WAIT UNTIL THE COLDER AIR ALOFT
ARRIVES TO STEEPEN THE LOW LEVEL LAPSE RATES FOR THE GUSTY WINDS TO
OCCUR...LIKELY IN THE 22-02Z TIME PERIOD. WILL KEEP HEADLINE TIMING
STATUS QUO. THE STRONG PRESSURE RISES SHIFT TO THE EAST BY
MIDNIGHT...AND WIND GUSTS SHOULD BE SUBSIDING BY THIS TIME. AS A
RESULT...STILL THINK THE EVENING OR MIDNIGHT CREW WILL BE ABLE TO
END WIND HEADLINES EARLY. THE COMBO OF GUSTY NW WINDS AND INCOMING
ARCTIC AIR WILL CREATE WIND CHILL READINGS OF 20-25 DEGREES BELOW
ZERO OVER CENTRAL AND NORTH-CENTRAL WISCONSIN LATE TONIGHT.
SUNDAY...ARCTIC AIR WILL CONTINUE TO POUR ACROSS THE REGION ON
SUNDAY. NORTHWEST WINDS WILL CONTINUE TO PRODUCE LAKE EFFECT SNOW
SHOWERS IN THE SNOW BELTS...BUT WINDS DO BACK A BIT SO SNOW SHOWERS
SHOULD BE GRADUALLY DIMINISHING OVER THE COURSE OF THE MORNING. AIR
WILL REMAIN TOO COLD FOR DENDRITIC SNOW GROWTH SO NOT EXPECTING MUCH
ACCUMS. OTHERWISE...STEEP LOW LEVEL LAPSE RATES AND FLOW OFF LAKE
SUPERIOR SHOULD KEEP SKIES PARTLY TO MOSTLY CLOUDY. TEMPS IN THE
SINGLE DIGITS TO LOWER TEENS.
LONG TERM...SUNDAY NIGHT THROUGH NEXT SATURDAY. DURATION OF THE
ARCTIC BLAST OF AIR THIS WEEK ALONG WITH LIKELY ADDITIONAL WIND
CHILL HEADLINES WILL BE THE PRIMARY ISSUE FOR THE FIRST HALF OF
THE NEW WEEK. ANOTHER CLIPPER SYSTEM IS PROGGED TO DROP INTO THE
REGION AROUND THURSDAY FOLLOWED WITH A REINFORCING BUT MILDER
AND PERHAPS BRIEFER SHOT OF ARCTIC AIR. SOME MDM RANGE MODELS ARE
INDICATING A MODERATING TREND LATER NEXT WEEKEND.
ADDITIONAL WIND CHILL HEADLINES WILL LIKELY BE POSTED LATER THIS
WEEKEND AS THE SATURDAY NIGHT HEADLINES EXPIRE. FORECAST TEMPS
SUGGEST THE COLDEST AIR ARRIVES LATER MONDAY WITH SOME CURRENT
VALUES APPROACHING WIND CHILL WARNING CRITERIA MONDAY NIGHT.
TYPICAL WITH THE VERY COLD PATTERNS...MODELS LIKELY OVERDOING THE
COVERAGE OF CLOUDS. WILL TONE DOWN CLOUDS OVER MOST LOCATIONS
EXCEPT FOR AREAS JUST DOWNSTREAM FROM LAKE SUPERIOR.
LAKE EFFECT SNOWS EXPECTED OVER FAR NORTH CENTRAL WISCONSIN WITH
THE COLD AIR INTRUSION. BUT APPEARS TO BE LIMITED AT THIS TIME
DUE TO THE DRY AIR MASS...FALLING INVERSION HEIGHTS...AND A BIT
TOO WESTERLY WIND DIRECTION.
TEMPS TO MODERATE TO NEAR SEASONAL LEVELS LATER THIS WEEK WITH A
CLIPPER SYSTEM DROPPING SOUTH INTO THE NORTHERN AND CENTRAL PLAINS
THURSDAY BEFORE PHASING WITH SOME SOUTHERN STREAM ENERGY THURSDAY
NIGHT. GFS IS INDICATING A POSSIBLE ADVISORY SNOW OVER THE SOUTH
HALF OR THIRD OF THE STATE THURSDAY NIGHT WITH THIS PHASED SYSTEM.
WILL GLANCE AT THE ECMWF THIS AFTERNOON TOO SEE IF A SIMILAR
TREND IN ORDER TO MAKE ANY ADJUSTMENTS...BUT GOING FORECAST THAT
FAR OUT REASONABLE.
&&
.AVIATION...FOR 00Z TAF ISSUANCE. ARCTIC FRONT SURGING SE ACRS THE
AREA. WL SEE A PERIOD OF STG WINDS AND SOME MVFR CIGS AND VSBYS
THIS EVENING. BRIEF IFR CONDITONS POSSIBLE. NOT REALLY THAT MUCH
SNOW TO BLOW ARND IN THE AREA...SO EXPECT CONDITIONS TO IMPROVE
BACK TO VFR BY LATE TNGT. THE EXCEPTION MAY BE IN THE FAR N /RHI/
WHERE CLDS OFF LAKE SUPERIOR WL CONT TO STREAM SE.
&&
.GRB WATCHES/WARNINGS/ADVISORIES...
WIND ADVISORY UNTIL 3 AM CST SUNDAY FOR WIZ038>040-048>050.
WIND ADVISORY UNTIL MIDNIGHT CST TONIGHT FOR WIZ030-031-035>037-
045.
WIND CHILL ADVISORY FROM MIDNIGHT TONIGHT TO 9 AM CST SUNDAY FOR
WIZ005-010-011-018-019-030-035-036.
WIND ADVISORY UNTIL 6 AM CST SUNDAY FOR WIZ022.
&&
$$
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
1142 AM CST FRI JAN 18 2013
.SHORT TERM...TODAY THROUGH SUNDAY NIGHT
314 AM CST FRI JAN 18 2013
THE MAIN FOCUS THROUGH THE WEEKEND IS WITH PRECIPITATION CHANCES
ALONG WITH THE TEMPERATURE DROP AND STRONG WINDS BEHIND THE FIRST
IN A SERIES OF COLD FRONTS THAT WILL MOVE THROUGH THE REGION.
CURRENTLY...A BAND OF SNOW EXTENDS FROM CENTRAL MINNESOTA DOWN
INTO SOUTHWEST WISCONSIN AHEAD OF A SURFACE WARM FRONT AND WILL
QUICKLY PROPAGATE TO THE EAST THIS MORNING. SOME OF THIS SNOW HAS
TAKEN ON A CONVECTIVE LOOK TO IT ACROSS CENTRAL MINNESOTA...LIKELY
DUE TO THE LOW LEVEL FRONTOGENESIS BEING SHOWN THERE ON 18.06Z RAP
CROSS SECTIONS...WITH SOME VISIBILITIES DROPPING DOWN TO A MILE AT
TIMES. THIS SNOW WILL BE OUT OF THE FORECAST AREA QUICKLY THIS
MORNING WITH SNOW TOTALS STILL LOOKS TO BE AROUND AN INCH OR TWO
IN NORTH CENTRAL WISCONSIN WITH LESS THAN AN INCH SOUTH OF CLARK
COUNTY WISCONSIN. CONFIDENCE NOT VERY HIGH THAT FREEZING DRIZZLE
WILL OCCUR AS THERE HAS BEEN LITTLE IN REPORTS OF IT ALONG THE
BACK EDGE OF THE SNOW. 18.06Z RAP SOUNDINGS SHOW THAT IF THERE IS
AN AREA WHERE THE FREEZING DRIZZLE IS POSSIBLE...IT MAY BE ACROSS
NORTH CENTRAL WISCONSIN WHERE THE COLUMN MAY LOSE ICE WITH LOW
LEVEL LIFT STILL STRONG. CEILINGS HAVE NOT BEEN VERY LOW
THOUGH...MAINLY ABOVE 2KFT...SO THINK THAT THE LOW LEVEL RH MAY BE
A LITTLE OVERDONE. WILL LEAVE THE FZDZ MENTION IN THE FORECAST FOR
NOW...BUT HAVE TRIMMED IT BACK TO JUST BEING POSSIBLE IN WEST
CENTRAL WISCONSIN...MAINLY ALONG AND NORTH OF I-94.
THE NEXT QUESTION IS WITH TEMPERATURES TODAY WITH MUCH OF THE
REGION BEING IN THE WARM SECTOR AS A WARM FRONT LIFTS NORTHEAST OF
THE REGION. THOUGH 850MB TEMPERATURES ARE ONLY AROUND 1 STANDARD
DEVIATION ABOVE THE NORM...HIGHS MAY COME CLOSE TO A RECORD AT
RST WHERE THE PREVIOUS RECORD IS 46. WITH JUST MID TO UPPER LEVEL
CLOUD COVER TO CONTEND WITH...AND LITTLE TO NO SNOW ON THE
GROUND...TEMPERATURES SHOULD CLIMB INTO THE 40S ACROSS MUCH OF THE
REGION. THE ECMWF HAS BEEN OUR BEST VERIFYING GUIDANCE WITH THE
RECENT WARM DAYS...SO HAVE FOLLOWED IT WITH THE TRENDS FOR TODAY.
THE HAMMER DROPS SATURDAY AS THE FIRST COLD FRONT COMES THROUGH IN
THE AFTERNOON WITH A SECONDARY ONE COMING THROUGH IN THE EVENING
THAT WILL BRING DOWN THE MUCH COLDER AIR AND STRONG/GUSTY WINDS.
THE STRONG COLD AIR ADVECTION AND TIGHT PRESSURE GRADIENT WILL
LEAD TO WIND GUSTS UP INTO THE 40MPH RANGE SATURDAY EVENING RIGHT
AFTER FROPA. THIS COMBINATION OF DROPPING TEMPERATURES AND GUSTY
WINDS COULD LEAD TO THE WIND CHILL DROPPING INTO THE -20F TO -25F
RANGE ACROSS SOUTHEAST MINNESOTA AND WESTERN WISCONSIN TO WHERE A
WIND CHILL ADVISORY MAY BE NEEDED. BUMPED UP CLOUD COVER A BIT
AND ADDED SOME FLURRIES BEHIND THE COLD FRONT AS 18.00Z NAM/GFS
SOUNDINGS SHOW SOME LOW LEVEL RH DROPPING INTO THE -10C TO -20C
RANGE.
ANOTHER WEAKLY FORCED SYSTEM WILL MOVE THROUGH IOWA ON SUNDAY AND
BRING ANOTHER POSSIBLE ROUND OF LIGHT SNOW ALONG WITH IT. WITH A
RIDGE OF HIGH PRESSURE PUSHING DOWN FROM THE NORTHWEST THOUGH...IT
WILL BE HARD TO SQUEEZE OUT MUCH IN THE WAY OF PRECIPITATION.
.LONG TERM...MONDAY THROUGH THURSDAY
314 AM CST FRI JAN 18 2013
THE MAIN FOCUS INTO NEXT WEEK IS WITH THE TEMPERATURES AND HOW LOW
THEY WILL GO. THE LACK OF SNOW ON THE GROUND WILL HELP TO KEEP
TEMPERATURES UP ABOUT 10 DEGREES FROM WHERE THEY NORMALLY COULD
DROP TO...BUT EVEN SO LOWS WILL DROP WELL BELOW ZERO MONDAY
MORNING AND TUESDAY MORNING. THE 18.00Z GEM IS THE COLDEST OF THE
MODEL RUNS WITH HAVING 850MB TEMPERATURES DROPPING DOWN TO -32C BY
MONDAY AFTERNOON...BUT THAT APPEARS TO BE A BIT EXTREME COMPARED
TO THE 18.00Z GFS/ECMWF WHICH HAVE 850MB TEMPERATURES AROUND -24C
AT THAT SAME TIME. WIND CHILL ADVISORIES WILL LIKELY BE NEEDED
MONDAY AND TUESDAY WITH WIND CHILLS DROPPING DOWN INTO THE -20F TO
-30F RANGE. THE SURFACE RIDGE AXIS PASSES BY ON WEDNESDAY MORNING
WITH WARMER LOW LEVEL AIR MOVING BACK IN THROUGH THE REST OF THE
WEEK. THE 18.00Z GFS/ECMWF CONTINUE TO HINT AT A LATE WEEK SYSTEM
MOVING THROUGH THE REGION...BUT THERE IS CONSIDERABLE SPREAD ON
WHERE THIS SYSTEM WILL TRACK.
&&
.AVIATION...THROUGH 18Z SATURDAY
1142 AM CST FRI JAN 18 2013
A WARM FRONT HAS LIFTED THROUGH THE TAF SITES...RESULTING IN A
BREEZY SOUTH TO SOUTHWEST WIND. BOTH TAF SITES SHOULD STAY FAIRLY
STEADY WITH THE SUSTAINED WINDS AND GUSTS THROUGH THE
AFTERNOON...BETWEEN 10-20 KT ON SUSTAINED WINDS AND 20-25 KT ON
GUSTS. EXPECT THE WINDS AND GUSTS TO DIMINISH QUICKLY AROUND
SUNSET WITH LOSS OF HEATING. PLENTY OF LOW LEVEL DRY AIR SHOULD
KEEP CONDITIONS VFR...UP TO THE ARRIVAL OF AN ARCTIC FRONT
CURRENTLY IN SOUTHERN ALBERTA. THIS FRONT SHOULD BEGIN TO APPROACH
THE TAF SITES NEAR 18Z SATURDAY. AHEAD OF THE FRONT...WINDS WILL
BEGIN TO TURN WESTERLY...AND THIS IS NOTED IN THE TAFS.
LOOKING AHEAD...EXPECT THE ARCTIC FRONT TO CROSS THE TAF SITES
AROUND 21Z SATURDAY. WINDS IMMEDIATELY AFTER PASSAGE WILL BE QUITE
STRONG...SUSTAINED LIKELY BETWEEN 20-30 KT WITH GUSTS OF
30-40KT...HIGHEST AT KRST. IN ADDITION...AN MVFR CLOUD DECK LOOKS
TO FOLLOW IN THE WAKE OF THE FRONT.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
314 AM CST FRI JAN 18 2013
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...HALBACH
LONG TERM...HALBACH
AVIATION...AJ
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
530 AM CST FRI JAN 18 2013
.SHORT TERM...TODAY THROUGH SUNDAY NIGHT
314 AM CST FRI JAN 18 2013
THE MAIN FOCUS THROUGH THE WEEKEND IS WITH PRECIPITATION CHANCES
ALONG WITH THE TEMPERATURE DROP AND STRONG WINDS BEHIND THE FIRST
IN A SERIES OF COLD FRONTS THAT WILL MOVE THROUGH THE REGION.
CURRENTLY...A BAND OF SNOW EXTENDS FROM CENTRAL MINNESOTA DOWN
INTO SOUTHWEST WISCONSIN AHEAD OF A SURFACE WARM FRONT AND WILL
QUICKLY PROPAGATE TO THE EAST THIS MORNING. SOME OF THIS SNOW HAS
TAKEN ON A CONVECTIVE LOOK TO IT ACROSS CENTRAL MINNESOTA...LIKELY
DUE TO THE LOW LEVEL FRONTOGENESIS BEING SHOWN THERE ON 18.06Z RAP
CROSS SECTIONS...WITH SOME VISIBILITIES DROPPING DOWN TO A MILE AT
TIMES. THIS SNOW WILL BE OUT OF THE FORECAST AREA QUICKLY THIS
MORNING WITH SNOW TOTALS STILL LOOKS TO BE AROUND AN INCH OR TWO
IN NORTH CENTRAL WISCONSIN WITH LESS THAN AN INCH SOUTH OF CLARK
COUNTY WISCONSIN. CONFIDENCE NOT VERY HIGH THAT FREEZING DRIZZLE
WILL OCCUR AS THERE HAS BEEN LITTLE IN REPORTS OF IT ALONG THE
BACK EDGE OF THE SNOW. 18.06Z RAP SOUNDINGS SHOW THAT IF THERE IS
AN AREA WHERE THE FREEZING DRIZZLE IS POSSIBLE...IT MAY BE ACROSS
NORTH CENTRAL WISCONSIN WHERE THE COLUMN MAY LOSE ICE WITH LOW
LEVEL LIFT STILL STRONG. CEILINGS HAVE NOT BEEN VERY LOW
THOUGH...MAINLY ABOVE 2KFT...SO THINK THAT THE LOW LEVEL RH MAY BE
A LITTLE OVERDONE. WILL LEAVE THE FZDZ MENTION IN THE FORECAST FOR
NOW...BUT HAVE TRIMMED IT BACK TO JUST BEING POSSIBLE IN WEST
CENTRAL WISCONSIN...MAINLY ALONG AND NORTH OF I-94.
THE NEXT QUESTION IS WITH TEMPERATURES TODAY WITH MUCH OF THE
REGION BEING IN THE WARM SECTOR AS A WARM FRONT LIFTS NORTHEAST OF
THE REGION. THOUGH 850MB TEMPERATURES ARE ONLY AROUND 1 STANDARD
DEVIATION ABOVE THE NORM...HIGHS MAY COME CLOSE TO A RECORD AT
RST WHERE THE PREVIOUS RECORD IS 46. WITH JUST MID TO UPPER LEVEL
CLOUD COVER TO CONTEND WITH...AND LITTLE TO NO SNOW ON THE
GROUND...TEMPERATURES SHOULD CLIMB INTO THE 40S ACROSS MUCH OF THE
REGION. THE ECMWF HAS BEEN OUR BEST VERIFYING GUIDANCE WITH THE
RECENT WARM DAYS...SO HAVE FOLLOWED IT WITH THE TRENDS FOR TODAY.
THE HAMMER DROPS SATURDAY AS THE FIRST COLD FRONT COMES THROUGH IN
THE AFTERNOON WITH A SECONDARY ONE COMING THROUGH IN THE EVENING
THAT WILL BRING DOWN THE MUCH COLDER AIR AND STRONG/GUSTY WINDS.
THE STRONG COLD AIR ADVECTION AND TIGHT PRESSURE GRADIENT WILL
LEAD TO WIND GUSTS UP INTO THE 40MPH RANGE SATURDAY EVENING RIGHT
AFTER FROPA. THIS COMBINATION OF DROPPING TEMPERATURES AND GUSTY
WINDS COULD LEAD TO THE WIND CHILL DROPPING INTO THE -20F TO -25F
RANGE ACROSS SOUTHEAST MINNESOTA AND WESTERN WISCONSIN TO WHERE A
WIND CHILL ADVISORY MAY BE NEEDED. BUMPED UP CLOUD COVER A BIT
AND ADDED SOME FLURRIES BEHIND THE COLD FRONT AS 18.00Z NAM/GFS
SOUNDINGS SHOW SOME LOW LEVEL RH DROPPING INTO THE -10C TO -20C
RANGE.
ANOTHER WEAKLY FORCED SYSTEM WILL MOVE THROUGH IOWA ON SUNDAY AND
BRING ANOTHER POSSIBLE ROUND OF LIGHT SNOW ALONG WITH IT. WITH A
RIDGE OF HIGH PRESSURE PUSHING DOWN FROM THE NORTHWEST THOUGH...IT
WILL BE HARD TO SQUEEZE OUT MUCH IN THE WAY OF PRECIPITATION.
.LONG TERM...MONDAY THROUGH THURSDAY
314 AM CST FRI JAN 18 2013
THE MAIN FOCUS INTO NEXT WEEK IS WITH THE TEMPERATURES AND HOW LOW
THEY WILL GO. THE LACK OF SNOW ON THE GROUND WILL HELP TO KEEP
TEMPERATURES UP ABOUT 10 DEGREES FROM WHERE THEY NORMALLY COULD
DROP TO...BUT EVEN SO LOWS WILL DROP WELL BELOW ZERO MONDAY
MORNING AND TUESDAY MORNING. THE 18.00Z GEM IS THE COLDEST OF THE
MODEL RUNS WITH HAVING 850MB TEMPERATURES DROPPING DOWN TO -32C BY
MONDAY AFTERNOON...BUT THAT APPEARS TO BE A BIT EXTREME COMPARED
TO THE 18.00Z GFS/ECMWF WHICH HAVE 850MB TEMPERATURES AROUND -24C
AT THAT SAME TIME. WIND CHILL ADVISORIES WILL LIKELY BE NEEDED
MONDAY AND TUESDAY WITH WIND CHILLS DROPPING DOWN INTO THE -20F TO
-30F RANGE. THE SURFACE RIDGE AXIS PASSES BY ON WEDNESDAY MORNING
WITH WARMER LOW LEVEL AIR MOVING BACK IN THROUGH THE REST OF THE
WEEK. THE 18.00Z GFS/ECMWF CONTINUE TO HINT AT A LATE WEEK SYSTEM
MOVING THROUGH THE REGION...BUT THERE IS CONSIDERABLE SPREAD ON
WHERE THIS SYSTEM WILL TRACK.
&&
.AVIATION...TODAY AND TONIGHT
530 AM CST FRI JAN 18 2013
CURRENT SURFACE MAP HAS A WARM FRONT EXTENDING FROM SD THROUGH
CENTRAL IA...MOVING NORTH INTO THE UPPER MISSISSIPPI RIVER REGION.
RADAR SHOWING -SN ACTIVITY ASSOCIATED WITH LIFT AHEAD OF THE WARM
FRONT WAS NOW ALONG/NORTHEAST OF I-94 WITH VFR CLOUD AT KRST/KLSE
TAF SITES. PLAN ON THE WARM FRONT TO LIFT NORTH OF THE AREA BY
LATER THIS MORNING WITH WINDS PICKING UP FROM THE SOUTH/SOUTHWEST
IN THE WARM SECTOR ALONG WITH SOME PATCHY ALTOCUMULUS FROM TIME TO
TIME. A WEAK MID-LEVEL TROUGH IS EXPECTED TO SPREAD BROKEN LAYER
OF ALTOCUMULUS WITH BASES AOA 8KFT INTO THE AREA LATE THIS
EVENING/OVERNIGHT. OTHERWISE...VFR CONDITIONS EXPECTED THROUGH
TONIGHT.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
314 AM CST FRI JAN 18 2013
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...HALBACH
LONG TERM...HALBACH
AVIATION...DAS
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
314 AM CST FRI JAN 18 2013
.SHORT TERM...TODAY THROUGH SUNDAY NIGHT
314 AM CST FRI JAN 18 2013
THE MAIN FOCUS THROUGH THE WEEKEND IS WITH PRECIPITATION CHANCES
ALONG WITH THE TEMPERATURE DROP AND STRONG WINDS BEHIND THE FIRST
IN A SERIES OF COLD FRONTS THAT WILL MOVE THROUGH THE REGION.
CURRENTLY...A BAND OF SNOW EXTENDS FROM CENTRAL MINNESOTA DOWN
INTO SOUTHWEST WISCONSIN AHEAD OF A SURFACE WARM FRONT AND WILL
QUICKLY PROPAGATE TO THE EAST THIS MORNING. SOME OF THIS SNOW HAS
TAKEN ON A CONVECTIVE LOOK TO IT ACROSS CENTRAL MINNESOTA...LIKELY
DUE TO THE LOW LEVEL FRONTOGENESIS BEING SHOWN THERE ON 18.06Z RAP
CROSS SECTIONS...WITH SOME VISIBILITIES DROPPING DOWN TO A MILE AT
TIMES. THIS SNOW WILL BE OUT OF THE FORECAST AREA QUICKLY THIS
MORNING WITH SNOW TOTALS STILL LOOKS TO BE AROUND AN INCH OR TWO
IN NORTH CENTRAL WISCONSIN WITH LESS THAN AN INCH SOUTH OF CLARK
COUNTY WISCONSIN. CONFIDENCE NOT VERY HIGH THAT FREEZING DRIZZLE
WILL OCCUR AS THERE HAS BEEN LITTLE IN REPORTS OF IT ALONG THE
BACK EDGE OF THE SNOW. 18.06Z RAP SOUNDINGS SHOW THAT IF THERE IS
AN AREA WHERE THE FREEZING DRIZZLE IS POSSIBLE...IT MAY BE ACROSS
NORTH CENTRAL WISCONSIN WHERE THE COLUMN MAY LOSE ICE WITH LOW
LEVEL LIFT STILL STRONG. CEILINGS HAVE NOT BEEN VERY LOW
THOUGH...MAINLY ABOVE 2KFT...SO THINK THAT THE LOW LEVEL RH MAY BE
A LITTLE OVERDONE. WILL LEAVE THE FZDZ MENTION IN THE FORECAST FOR
NOW...BUT HAVE TRIMMED IT BACK TO JUST BEING POSSIBLE IN WEST
CENTRAL WISCONSIN...MAINLY ALONG AND NORTH OF I-94.
THE NEXT QUESTION IS WITH TEMPERATURES TODAY WITH MUCH OF THE
REGION BEING IN THE WARM SECTOR AS A WARM FRONT LIFTS NORTHEAST OF
THE REGION. THOUGH 850MB TEMPERATURES ARE ONLY AROUND 1 STANDARD
DEVIATION ABOVE THE NORM...HIGHS MAY COME CLOSE TO A RECORD AT
RST WHERE THE PREVIOUS RECORD IS 46. WITH JUST MID TO UPPER LEVEL
CLOUD COVER TO CONTEND WITH...AND LITTLE TO NO SNOW ON THE
GROUND...TEMPERATURES SHOULD CLIMB INTO THE 40S ACROSS MUCH OF THE
REGION. THE ECMWF HAS BEEN OUR BEST VERIFYING GUIDANCE WITH THE
RECENT WARM DAYS...SO HAVE FOLLOWED IT WITH THE TRENDS FOR TODAY.
THE HAMMER DROPS SATURDAY AS THE FIRST COLD FRONT COMES THROUGH IN
THE AFTERNOON WITH A SECONDARY ONE COMING THROUGH IN THE EVENING
THAT WILL BRING DOWN THE MUCH COLDER AIR AND STRONG/GUSTY WINDS.
THE STRONG COLD AIR ADVECTION AND TIGHT PRESSURE GRADIENT WILL
LEAD TO WIND GUSTS UP INTO THE 40MPH RANGE SATURDAY EVENING RIGHT
AFTER FROPA. THIS COMBINATION OF DROPPING TEMPERATURES AND GUSTY
WINDS COULD LEAD TO THE WIND CHILL DROPPING INTO THE -20F TO -25F
RANGE ACROSS SOUTHEAST MINNESOTA AND WESTERN WISCONSIN TO WHERE A
WIND CHILL ADVISORY MAY BE NEEDED. BUMPED UP CLOUD COVER A BIT
AND ADDED SOME FLURRIES BEHIND THE COLD FRONT AS 18.00Z NAM/GFS
SOUNDINGS SHOW SOME LOW LEVEL RH DROPPING INTO THE -10C TO -20C
RANGE.
ANOTHER WEAKLY FORCED SYSTEM WILL MOVE THROUGH IOWA ON SUNDAY AND
BRING ANOTHER POSSIBLE ROUND OF LIGHT SNOW ALONG WITH IT. WITH A
RIDGE OF HIGH PRESSURE PUSHING DOWN FROM THE NORTHWEST THOUGH...IT
WILL BE HARD TO SQUEEZE OUT MUCH IN THE WAY OF PRECIPITATION.
.LONG TERM...MONDAY THROUGH THURSDAY
314 AM CST FRI JAN 18 2013
THE MAIN FOCUS INTO NEXT WEEK IS WITH THE TEMPERATURES AND HOW LOW
THEY WILL GO. THE LACK OF SNOW ON THE GROUND WILL HELP TO KEEP
TEMPERATURES UP ABOUT 10 DEGREES FROM WHERE THEY NORMALLY COULD
DROP TO...BUT EVEN SO LOWS WILL DROP WELL BELOW ZERO MONDAY
MORNING AND TUESDAY MORNING. THE 18.00Z GEM IS THE COLDEST OF THE
MODEL RUNS WITH HAVING 850MB TEMPERATURES DROPPING DOWN TO -32C BY
MONDAY AFTERNOON...BUT THAT APPEARS TO BE A BIT EXTREME COMPARED
TO THE 18.00Z GFS/ECMWF WHICH HAVE 850MB TEMPERATURES AROUND -24C
AT THAT SAME TIME. WIND CHILL ADVISORIES WILL LIKELY BE NEEDED
MONDAY AND TUESDAY WITH WIND CHILLS DROPPING DOWN INTO THE -20F TO
-30F RANGE. THE SURFACE RIDGE AXIS PASSES BY ON WEDNESDAY MORNING
WITH WARMER LOW LEVEL AIR MOVING BACK IN THROUGH THE REST OF THE
WEEK. THE 18.00Z GFS/ECMWF CONTINUE TO HINT AT A LATE WEEK SYSTEM
MOVING THROUGH THE REGION...BUT THERE IS CONSIDERABLE SPREAD ON
WHERE THIS SYSTEM WILL TRACK.
&&
.AVIATION...THROUGH 06Z SATURDAY
1128 PM CST THU JAN 17 2013
A BAND OF SNOW NOW OVER NORTH DAKOTA IS EXPECTED TO MOVE/EXPAND
SOUTHEASTWARD OVERNIGHT IN ZONE OF WARM ADVECTION AHEAD OF A WEAK
SHORTWAVE. MODELS CONSISTENT WITH THE TAF SITES BEING ON THE
SOUTHWESTERN EDGE OF THE PRECIPITATION SHIELD...ESPECIALLY KRST.
EXPECT LOWER LAYERS TO SATURATE THROUGH 09Z WITH IFR TO MVFR
CEILINGS DEVELOPING AS THE SNOW MOVES IN AROUND 09Z. FEEL KLSE
STILL HAS A BETTER CHANCE AT MEASURABLE SNOW SO DID CONTINUE THE
IFR VISIBILITIES FOR A FEW HOURS...WHILE ADDRESSED THIS AS A TEMPO
GROUP AT KRST. STILL SOME CONCERN FOR A LITTLE FREEZING DRIZZLE ON
THE BACK SIDE OF THE PRECIPITATION SHIELD AS BUFKIT SOUNDINGS
CONTINUE TO SHOW A LOSS OF ICE, HOWEVER...AM CONCERNED THAT
PRECIPITATION MAY BE ENDED BY THE TIME THERE IS A LOSS OF ICE.
THUS DID NOT INCLUDE IN THE TAFS. OTHERWISE...IMPROVING CONDITIONS
EXPECTED THROUGH THE MORNING HOURS WITH CEILINGS RISING AND CLOUDS
SCATTERING OUT DURING THE AFTERNOON. STRONG SOUTHWEST WINDS WILL
GUST TO 26 KNOTS AT KRST DURING THE AFTERNOON.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
314 AM CST FRI JAN 18 2013
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...HALBACH
LONG TERM...HALBACH
AVIATION...RABERDING
AREA FORECAST DISCUSSION
NWS MELBOURNE FL
357 AM EST SUN JAN 20 2013
.DISCUSSION...
CURRENTLY...
HI PRES RIDGE OVR THE DEEP SOUTH HAS WEAKENED CONSIDERABLY OVER THE
PAST 24HRS. ERLY FLOW ACRS CENTRAL FL HAS DIMINISHED AS A RESULT. AN
H100-H85 TROF EXTENDS FROM THE NRN BAHAMAS TO THE SE GOMEX. THE USAF
CAPE PROFILER AND THE KTBW VAD WIND PROFILE CONTINUE TO HOLD 15-20KT
ENE WINDS THRU 4KFT. THIS IS LIKELY DUE TO THE INTERACTION BTWN THE
RIDGE AND THE TROF AS VAD WINDS AT KJAX/KMFL THRU 4KFT DIMINISH AOB
10KTS. HIGH REGIONAL MOISTURE THRU THE H100-H85 LYR PER SATELLITE
IMAGERY AND LATEST RAP ANALYSIS...MEAN RH VALUES BTWN 75-95PCT. THE
00Z KMFL/KTBW SOUNDINGS REMAIN SATURATED THRU THE H100-H80 LYR WITH
PWAT VALUES BTWN 1.0"-1.2"...UP FROM 0.8" ON THE 19/00Z RUN. A SHARP
SUBSIDENCE INVERSION REMAINS ABV H80 WITH VERY DRY AIR ALOFT. RADAR
SHOWS AREAS OF -RA MVG ONSHORE S OF CAPE CANAVERAL. PATCHY DENSE FOG
NOTED ALONG THE TREASURE COAST.
TODAY-TONIGHT...
MCLDY SKIES TO CONTINUE AS THE LOW LVL MOISTURE POOLS WITHIN THE
TROF WHILE REMAINING TRAPPED BELOW THE SUBSIDENCE INVERSION. STEADY
STATE E/NE FLOW THRU THE H100-H85 LYR WILL CONTINUE TO PUSH POCKETS
OF -RA ONSHORE...QPF BTWN 0.10"-0.25" S OF SEBASTIAN INLET...AOB
0.10" ELSEWHERE. FOR TODAY...WILL GO WITH 30 POPS ROUGHLY S OF LINE
FROM KISSIMMEE TO TITUSVILLE...20 POPS TO THE N. MAX TEMPS SIMILAR
TO SAT...GENERALLY L/M70S THOUGH AREAS AROUND LAKE OKEECHOBEE
COULD PUSH INTO THE U70S.
H100-H85 LYR WILL REMAIN SATURATED OVERNIGHT AS A CANADIAN HI PRES
RIDGE PUSHES OUT OF ALBERTA AND ABSORBS THE WEAK RIDGE OVER THE DEEP
SOUTH. THE NE FLOW WILL DIMINISH AS A RESULT...WHICH WILL MAKE IT
MORE DIFFICULT FOR SHRAS TO PUSH ONSHORE...LET ALONE INTO THE
INTERIOR. WILL KEEP SMALL POPS IN FOR THE SPACE/TREASURE COASTS AS
WELL AS OKEECHOBEE AND SRN OSCEOLA COUNTIES...BLO MENTIONABLE POPS
ELSEWHERE. DESPITE BLANKETING CLOUD COVER...THE DIMINISHED ONSHORE
FLOW SHOULD ALLOW MIN TEMPS TO COOL L/M50S ALONG AND N OF I-4 AND
M/U50S TO THE S...IMMEDIATE SPACE/TREASURE COASTS WILL HOLD IN THE
L/M60S.
MON-TUE...00Z GFS AND ECMWF MODELS BOTH SHOW MOISTURE LINGERING A
BIT LONGER AND A SLIGHT DELAY IN COOLER/DRIER AIRMASS
OVERSPREADING THE AREA. AS A RESULT...HAVE EXPANDED LOW RAIN
CHANCES FOR MONDAY TO ENCOMPASS MOST OF EC FL EXCEPT FAR NORTH
LAKE/VOLUSIA. FOCUSED RAIN CHANCES (30 POP) SOUTH OF THE CAPE NEAR
THE COAST. FORECAST MODEL SOUNDINGS SHOW CONTINUED CONSIDERABLE
STRATOCUMULUS CLOUDS MONDAY WITH INCREASING CIRRUS SHIELD FROM
RIGHT ENTRANCE REGION OF VERY STRONG (130 KT) UPPER JET.
THEN HIGH PRESSURE BUILDING SE FROM THE NORTHERN PLAINS WILL BRING
A SLIGHTLY COOLER BUT MUCH DRIER AIRMASS INTO THE AREA DURING
TUESDAY. THIS WILL SUPPRESS RAIN CHANCES TO THE FAR SOUTH...MARTIN
COAST. MAX TEMPS LOOK ONLY 3-5 DEGREES COOLER WITH INCREASING
SUNSHINE AS CIRRUS THINS AND NOTICEABLY LOWER DEWPOINTS. LOWS TUE
NIGHT/WED MORNING MAY REACH AS LOW AS THE UPPER 30S ACROSS FAR
NORTHERN LAKE AND NW VOLUSIA COUNTIES WITH WIDESPREAD UPPER
40S/LOWER 50S ELSEWHERE.
WED-SAT...COOL AND DRY CONDITIONS EXPECTED WED-THU AS HIGH
PRESSURE CENTER SHIFTS EAST ACROSS NORTH FL. TEMPERATURES FORECAST
TO BE AT OR SLIGHTLY BELOW NORMAL WEDNESDAY AND WED NIGHT BUT NO
FREEZING TEMPS ARE EXPECTED. MAX TEMPS BEGIN TO REBOUND THU...VERY
CLOSE TO SEASONAL NORMS IN THE LOWER TO MID 70S. HIGH PRESSURE
PUSHES OFFSHORE THU NIGHT SETTING UP A WARMER FRIDAY WITH SOUTHERLY
FLOW...A FAIR AMOUNT OF SUN AND MAX TEMPS IN THE MID TO UPPER 70S.
THE 00Z ECMWF PULLS A SLUG OF DEEP MOISTURE NORTHWARD ACROSS THE
FL PENINSULA FRI AND GENERATES A LARGE AREA OF RAINFALL AHEAD OF
THE NEXT COLD FRONT. BUT HAVE LEANED TOWARD THE 00Z GFS IN
KEEPING FRI RAIN-FREE. BOTH GFS AND ECMWF MODELS SWEEP THE COLD
FRONT THROUGH THE AREA EARLY SAT. PREFER THE GFS SOLUTION SHOWING
A THIN BAND OF FAST MOVING SHOWERS ASSOCD WITH THE FRONT WITH
SOME GUSTY WINDS. BOTH MODELS SHOW VEERING LOW LEVEL FLOW TO THE
W/SW AHEAD OF THE FRONT WHICH...AMONG OTHER THINGS...LOOKS TO
KEEP THE SEVERE WEATHER THREAT TO A MINIMUM.
&&
.AVIATION...
THRU 20/15Z...PREVAILING CIGS BTWN FL030-040...AREAS MVFR/LCL IFR
VSBYS/CIGS IN PATCHY FOG/STRATUS...-RA ALNG THE COAST S OF KTIX.
AFT 20/15Z...PREVAILING CIGS BTWN FL040-060...S OF KTIX-KISM SCT
MVFR SHRAS...N OF KTIX-KISM ISOLD MVFR SHRAS.
&&
.MARINE...
TODAY-TONIGHT...WEAK LOW LVL TROF EXTENDING FROM THE NRN BAHAMAS TO
THE SE GOMEX WILL INTERACT WITH A WEAK HI PRES RIDGE OVER THE DEEP
SOUTH TO MAINTAIN A GENTLE TO MODERATE NERLY BREEZE ACRS THE LCL
ATLC. THESE WINDS WILL PUSH A 3-4FT SWELL INTO THE E FL COAST...
KEEPING SEAS IN THE 4-6FT RANGE THRU LATE THIS EVNG. SWELL WILL
GRADUALLY DAMPEN OUT OVERNIGHT WITH SEAS FALLING TO 3-5FT BY
DAYBREAK MON.
BUOY009 MEASURING A DOMINANT PD ARND 7SEC. THIS IS MOST LIKELY A
REFLECTION OF THE INTERACTION BTWN THE GULF STREAM AND THE
PREVAILING NE BREEZE AS ALL OTHER BUOYS HAVE DOMINANT PDS AOA 10SEC.
AS SUCH...WILL ALLOW THE SCA TO EXPIRE BUT WILL KEEP A CAUTIONARY
STATEMENT FOR THE GULF STREAM.
MON-THU...PRETTY FAVORABLE BOATING CONDITIONS MONDAY WITH LIGHT NE
WINDS AROUND 10 KNOTS AND A 3 FT NE SWELL. HIGH PRESSURE BUILDING
SE FROM THE UPPER PLAINS WILL INCREASE THE NORTHERLY GRAD WIND
15-20 KNOTS EARLY TUE THRU TUE NIGHT WITH BOATING CONDITIONS
BECOMING LESS FAVORABLE. SEAS WILL BUILD TO 5 FT BY LATE TUE AND
MAY SEE 6 FT IN THE GULF STREAM TUE NIGHT INTO EARLY WED SO WILL
LIKELY NEED AT LEAST A CAUTION HEADLINE. WINDS WILL DECREASE BY
THU ESP ACROSS NORTH/CENTRAL WATERS AS HIGH PRESSURE CENTER TRACKS
EAST ACROSS NORTH FL.
&&
.FIRE WEATHER...
NO LOW RH CONCERNS THROUGH MONDAY. COOLER AND MUCH DRIER AIR IS
FORECAST TO OVERSPREAD THE AREA TUE INTO WED AND PRODUCE MIN RH
VALUES BELOW 35 PERCENT EACH AFTN. N/NW WINDS DO NOT LOOK QUITE
AS STRONG NOW BEHIND THE FRONT TUE BUT THERE SHOULD BE SOME GUSTS
UP TO 20 MPH IN THE AFTN. LIGHTER WINDS WED AND THU WILL NOT
MODIFY THE DRY AIRMASS MUCH.
&&
.PRELIMINARY POINT TEMPS/POPS...
DAB 71 57 73 52 / 20 10 20 10
MCO 75 58 76 56 / 20 10 20 10
MLB 74 64 77 61 / 30 20 30 20
VRB 75 63 77 60 / 30 20 30 20
LEE 75 55 74 53 / 20 10 10 10
SFB 75 57 75 54 / 20 10 20 10
ORL 75 58 75 56 / 20 10 20 10
FPR 76 63 77 60 / 30 20 30 20
&&
.MLB WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
AM...NONE.
&&
$$
SHORT TERM...BRAGAW
LONG TERM....KELLY
AREA FORECAST DISCUSSION
NWS DULUTH MN
1132 PM CST SAT JAN 19 2013
.AVIATION...06Z TAFS.
A WEAK SFC TROF OVER NORTHERN MN IS THE DIVIDING LINE BETWEEN VFR
AND MVFR. INL IS VFR BEING ON THE NORTH SIDE OF THE TROF WHILE THE
OTHER SITES HAVE MVFR CIGS. DLH IS VFR DUE TO ITS PROXIMITY TO
LAKE SUPERIOR WHERE DRY AIR HAS ERODED THE MVFR CIGS. EXPECT AN
IMPROVEMENT AT MVFR SITES TO VFR BY 12Z. ANOTHER BATCH OF LOW END
VFR CLOUDS ARRIVES AROUND 19Z IN ADVANCE OF THE SHORT WAVE
DROPPING THROUGH THE AREA.
&&
.PREV DISCUSSION... /ISSUED 822 PM CST SAT JAN 19 2013/
UPDATE...PUSHED THE WIND ADVISORY START TIME TO NOW AS IT WAS NOT
DUE TO START UNTIL 03Z. GNA HAS GUSTED TO 57 MPH IN THE LAST HALF
HOUR. REST OF THE FORECAST ON TRACK.
PREV DISCUSSION... /ISSUED 631 PM CST SAT JAN 19 2013/
UPDATE...DROPPED THE WIND ADVISORY FROM THE SOUTHERN MN ZONES.
GUSTY WINDS STILL EXPECTED UNTIL NEAR 06Z. WITH THE EXPECTED
CLEARING TREND...DROP MIN TEMPS A BIT. NO OTHER CHANGES TO
HEADLINES.
PREV DISCUSSION... /ISSUED 525 PM CST SAT JAN 19 2013/
AVIATION...00Z TAFS.
TIGHT PRESSURE GRADIENT OVER THE FA AT THE BEGINNING OF THE
FORECAST...BUT WILL LOOSEN ITS GRIP THROUGH THE EVENING AND GUSTY
WINDS WILL DIMINISH AROUND 06Z. MVFR WITH AREAS OF IFR WILL
IMPROVE TO VFR ABOUT THE SAME TIME THE GUSTY WINDS DIMINISH.
EXPECT A MID DECK OF CLOUDS AFTER 18Z SUNDAY AHEAD OF A SHORT WAVE
TROF MOVING THROUGH THE FA.
PREV DISCUSSION... /ISSUED 336 PM CST SAT JAN 19 2013/
SHORT TERM.../NOW - SUNDAY NIGHT/
THE MAIN CHALLENGES FOR THIS FORECAST INCLUDE 1) THE THREAT OF
STRONG WINDS ACROSS THE NORTHLAND THROUGH TONIGHT IN THE WAKE OF A
STRONG COLD FRONT...2) THE THREAT OF LAKE EFFECT SNOW FOR THE
GOGEBIC RANGE AND 3) THE THREAT OF HAZARDOUS WIND CHILL VALUES
TONIGHT AND TOMORROW MORNING. THE MODELS ARE IN REASONABLE
AGREEMENT...SO LEANED ON A BLEND. THE LATEST HIGH RESOLUTIONS
MODELS INDICATE STRONG WIND GUSTS ALONG THE NORTH SHORE
TONIGHT...SO ISSUED A WIND ADVISORY FOR THE NORTH SHORE THAT IS
SEPARATE FROM THE WIND ADVISORY FOR PARTS OF EAST CENTRAL
MINNESOTA AND NORTHWESTERN WISCONSIN.
AT 2130Z...THERE WAS A STRONG CLIPPER SYSTEM CENTERED OVER UPPER
PENINSULA MICHIGAN. THE NORTHLAND HAD STRONG W TO NW WINDS...WHICH
WERE GENERALLY STRENGTHENING IN THE WAKE OF THE CLIPPER. THE
NORTHLAND HAD CLOUDY SKIES. TEMPERATURES RANGED FROM THE LOW TO
MID 30S IN THE FAR EASTERN FA TO THE SINGLE DIGITS IN THE FAR NW
FA.
THROUGH TONIGHT...THE CLIPPER SYSTEM WILL CONTINUE TO MOVE EAST.
THE STRONG NW WINDS CARRYING QUITE THE ARCTIC BLAST WILL CONTINUE
TO INCREASE LATE THIS AFTERNOON...PERHAPS PEAK EARLY THIS
EVENING...THEN GRADUALLY RELAX THROUGH THE REST OF THE NIGHT. THE
EXCEPTION COULD BE ALONG THE IMMEDIATE NORTH SHORE WHERE
WINDS...ESPECIALLY GUSTS...WILL LIKELY STRENGTHEN INTO THIS
EVENING AND PEAK AROUND MIDNIGHT. THIS IS BASED ON THE LATEST RUNS
OF THE HRRR AND LOCAL WRF MODELS. THOSE MODELS SUGGEST WIND GUSTS
UP TO 50 KT. NOT SURE IF THE GUSTS WILL BE THAT STRONG...BUT
DECIDED TO ISSUE A WIND ADVISORY FOR THE NORTH SHORE THROUGH 09Z
TONIGHT FOR GUSTS UP TO 50 MPH. THE CURRENT WIND ADVISORY FROM
SOUTHERN CASS COUNTY TO BURNETT COUNTY STILL LOOKS GOOD THROUGH
03Z. WIND CHILL VALUES WILL PLUMMET TONIGHT WITH THE FALLING
TEMPERATURES...AND THE CURRENT WIND CHILL ADVISORY FOR TONIGHT AND
INTO TOMORROW MORNING DOES NOT NEED ANY CHANGES. LAKE EFFECT SNOW
SHOWERS WILL INCREASE ACROSS THE SOUTH SHORE TONIGHT...ESPECIALLY
THE GOGEBIC RANGE IN IRON COUNTY...AS THE STRONG COLD NW WINDS
DEVELOP OVER WESTERN LAKE SUPERIOR. WILL NOT BE MAKING CHANGES TO
THE CURRENT LAKE EFFECT SNOW ADVISORY FOR IRON COUNTY AS PARTS OF
THE COUNTY COULD GET SEVERAL INCHES OF SNOW THROUGH SUNDAY
MORNING.
SUNDAY AND SUNDAY NIGHT...IT WILL BE A PARTICULARLY COLD DAY
ACROSS THE NORTHLAND WITH MUCH OF REGION NOT EVEN REACHING ZERO
DEGREES. LAKE EFFECT SNOW SHOWERS WILL LIKELY CONTINUE FOR THE
SOUTH SHORE. ANOTHER WIND CHILL ADVISORY OR WARNING WILL LIKELY BE
NEEDED. SOME PARTS OF FAR NORTHERN MINNESOTA COULD HAVE WIND CHILL
VALUES APPROACHING 50 DEGREES BELOW ZERO.
LONG TERM.../MONDAY - FRIDAY NIGHT/
MODELS SHOWING GOOD AGREEMENT THAT THE CORE OF COLDEST H85-H50 AIR
PUSHES INTO THE NORTHERN AREAS EARLY MONDAY MORNING...SWINGING
THROUGH THE NORTHLAND THROUGH 00Z TUESDAY. AT THIS TIME WIND CHILL
VALUES IN THE NEIGHBORHOOD OF NEGATIVE 30 TO 50 ARE EXPECTED EARLY
MONDAY MORNING WITH VERY LITTLE IMPROVEMENT THROUGH THE DAY. THE
LATEST ECM/GFS SUGGEST THAT THE WRN LAKE SUPERIOR REGION REMAINS ON
THE BACK EDGE OF THE ARCTIC AIR MASS THROUGH MUCH OF THE WEEK WITH A
PERSIST ANT NORTHWEST FLOW. HAVE KEPT POPS ACROSS THE SOUTH SHORE
ZONES FOR AN ONGOING PERIOD OF LAKE EFFECT SNOW AS WELL.
AVIATION.../18Z TAF ISSUANCE/
MVFR CIGS WITH -SN AND BLSN WILL PREVAIL THROUGH 00Z..THEN
GRADUALLY IMPROVING TO VFR GENERALLY AFTER 06Z. NORTHWEST WINDS
WILL INCREASE THROUGH THE AFTERNOON WITH GUSTS OF 30 TO 35 KTS
COMMON ACROSS THE FORECAST ARES THROUGH THE 20Z TO 06Z PERIOD.
HIGHER GUSTS AROUND 40 KT WILL BE POSSIBLE AT THE KBRD AND KDLH
TERMINALS AROUND 00Z...WITH THE STRONGEST GUSTS OF 45-50 KT
EXPECTED ALONG THE NORTH SHORE OF LAKE SUPERIOR AFTER 03Z.
&&
.POINT TEMPS/POPS...
DLH -10 0 -21 -9 / 10 10 10 10
INL -20 -5 -30 -12 / 10 10 10 10
BRD -12 1 -22 -10 / 10 10 10 0
HYR -9 3 -18 -7 / 20 10 10 10
ASX -3 6 -13 -4 / 60 30 50 40
&&
.DLH WATCHES/WARNINGS/ADVISORIES...
MN...WIND CHILL ADVISORY UNTIL NOON CST SUNDAY FOR MNZ010>012-018>021-
025-026-033>038.
WIND ADVISORY UNTIL 3 AM CST SUNDAY FOR MNZ020-021.
WI...WIND CHILL ADVISORY UNTIL NOON CST SUNDAY FOR WIZ001>004-006>009.
LAKE EFFECT SNOW ADVISORY UNTIL NOON CST SUNDAY FOR WIZ004.
LS...NONE.
&&
$$
AVIATION...GSF
AREA FORECAST DISCUSSION
NWS GREEN BAY WI
1034 PM CST SAT JAN 19 2013
UPDATED AVIATION PORTION FOR 06Z TAF ISSUANCE AND ADD NEW UPDATE
SECTION
.UPDATE...ANTICIPATE BEING ABLE TO ALLOW THE WIND ADVISORY FOR
CENTRAL WI TO EXPIRE AS SCHEDULED AT MIDNIGHT. STILL WINDY
THERE...BUT IT SEEMS TO HAVE PEAKED AND WINDS WERE STARTING TO
SLOWLY DECR.
.PREV DISCUSSION...ISSUED AT 757 PM CST SAT JAN 19 2013...
UPDATE...GOING TO REPLACE THE WIND CHILL ADVISORY FOR VILAS
COUNTY WITH A WINTER WX ADVISORY AS A CATCH ALL FOR THE
SNOW...WIND...AND LOW WIND CHILLS LATER TONIGHT. VSBYS STILL LOW
BACK TO THE NW OF THERE AT IWD/ASX...AND TRAJ BECOMING MORE
FAVORABLE FOR ADDITIONAL LAKE-EFFECT. SUBSIDENCE/DRIER AIR
ARRIVING OVER THE LAKE WL EVENTUALLY SHUT THINGS DOWN. BUT GIVEN
THE SNOW THATS ALREADY FALLEN...THE WIND TO BLOW IT AROUND...AND
THE PLUMMETING TEMPS LIKELY RESULTING IN ICY ROADWAYS...IT SEEMS
THE MAIN HAZARD THE REST OF THE NGT WL BE MORE SN/BLSN RELATED
RATHER THAN WIND CHILL RELATED.
THE REST OF THE N WL HAVE TRAVEL PROBLEMS TOO...BUT ADDITIONAL
SNOWFALL WL BE MUCH LIGHTER AS LAKE-EFFECT WON/T BE A MAJOR FACTOR
AS IN VILAS.
THE OTHER HEADLINES SEEM TO BE ON TRACK...SO AT THIS POINT DON/T
PLAN ON MAKING ANY CHGS UNTIL WE GET CLOSER TO THE SCHEDULED
EXPIRATION OF THE WIND ADVSIORY OVER THE WRN PART OF THE AREA LATE
THIS EVENING.
SKOWRONSKI
DISCUSSION...ISSUED AT 600 PM CST SAT JAN 19 2013...
UPDATE...SPOTTER REPORT FROM ONEIDA COUNTY INDICATING VERY POOR
TRAVEL CONDITIONS. VSBY DOWN TO NEAR ZERO IN SN/BLSN. PLUS...TEMPS
PLUNGING BLO FZG WL LIKELY CAUSE ROADS TO ICE OVER AS WELL. THE
LOW VSBYS SHOULD BE RELATIVELY BRIEF...BUT THEIR SUDDEN ONSET WL
PROBABLY STILL CAUSE SIG PROBLEMS FOR ANYONE OUT ON THE ROADS.
SENT UPDATED SPS TO HIGHLIGHT THE SITN.
STILL NOT CERTAIN JUST HOW FAR S AND E THE POOR CONDITIONS WL
REACH. RADAR SHOWS A DEFINITE INCR IN SHSN ACTIVITY OVER CENTRAL
AND INTO E-C WI. BUT WE WERE WARM ENOUGH HERE AT THE OFFICE TO GET
SOME RAIN AS THE PCPN TYPE. ALTHOUGH CONDITIONS PROBABLY WON/T GET
QUITE AS BAD AS IN THE NW PART OF THE FCST AREA BECAUSE THE TEMP
DROP TO BLO FZG WL LAG A LITTLE FARTHER BEHIND THE PCPN...COULD
STILL GET SOME NASTY TRAVEL CONDITIONS AT TIMES.
UPDATED PRODUCT SUITE ALREADY SENT...THOUGH PREV FCST ALREADY HAD
THE GIST OF THE SITN PRETTY WELL SPELLED OUT.
SKOWRONSKI
DISCUSSION ISSUED AT 443 PM CST SAT JAN 19 2013...
SHORT TERM...TONIGHT AND SUNDAY.
LATEST RUC ANALYSIS AND SATELLITE/RADAR IMAGERY SHOW A STRONG
SHORTWAVE DIVING SE OVER NORTHERN MINNESOTA...WHICH IS DRIVING A
SURFACE LOW OVER WESTERN LAKE SUPERIOR. ARCTIC COLD FRONT EXTENDS
WESTWARD FROM THIS LOW OVER CENTRAL MINNESOTA AND NORTHERN SOUTH
DAKOTA. RETURNS ON RADAR OVER WESTERN WISCONSIN MAY NOT BE HITTING
THE GROUND...BUT THERE IS SCATTERED SNOW SHOWERS OCCURRING ALONG THE
ARCTIC FRONT AND JUST AHEAD OF THE SHORTWAVE...WHICH ARE DROPPING
VISIBILITIES TO AROUND A MILE AT TIMES. WINDS ARE ALSO RAPIDLY
INCREASING BEHIND THE FRONT...WITH SOME WIDELY SCATTERED REPORTS
JUST HIGHER THAN 40 KTS. TEMPERATURES BEHIND THE FRONT ARE FALLING
QUICKLY INTO THE SINGLE DIGITS ABOVE ZERO...WHILE READINGS ARE IN
THE UPPER 30S TO LOWER 40S ACROSS NORTHERN WISCONSIN. WITH THE
PASSAGE OF THE ARCTIC FRONT THIS EVENING...TEMPERATURE AND WIND
HEADLINES ARE THE MAIN FORECAST CONCERNS.
TONIGHT...THE STRONG SHORTWAVE WILL PUSH THE ARCTIC COLD FRONT
RAPIDLY SOUTHEAST ACROSS NORTH-CENTRAL WISCONSIN LATER THIS
AFTERNOON...AND NORTHEAST WISCONSIN EARLY THIS EVENING. DESPITE
STRONG MID AND UPPER LEVEL FORCING IN THE FORM OF -DIVQ AND
DIVERGENCE AHEAD OF THE WAVE...MID-LEVELS STRUGGLE TO SATURATE. SO
THINK WILL SEE NOT MUCH MORE THAN A SCT LINE OF SNOW SHOWERS JUST
AHEAD OF THE SHORTWAVE...WHICH WILL PROVIDE A BRIEF BURST OF SNOW
AND REDUCE VISIBILITIES...BUT NOT MUCH IN THE WAY OF ACCUMS. SO
WILL KEEP POPS IN THE LOW CHANCE RANGE OVER NE WISCONSIN FOR EARLY
THIS EVENING WITH THE FRONTAL PASSAGE. CLOUDS EXTEND NORTH ACROSS
MINNESOTA TO THE CANADIAN BORDER WHERE SNOW SHOWERS CONTINUE TO FALL
UNDER A LOW OVERCAST. SO THINK SNOW SHOWERS WILL FALL OVER
NORTH-CENTRAL WISCONSIN FOR MUCH OF THE EVENING. BEHIND THE FRONT
BY LATE IN THE EVENING...LOW LEVEL WINDS WILL SHIFT TO THE NORTHWEST
WITH GOOD TRAJECTORIES FOR LAKE EFFECT SNOW ACCUMULATIONS.
HOWEVER...850MB TEMPS WILL BE PLUMMETING INTO THE LOWER 20S BELOW
ZERO WHICH IS GETTING TOO COLD FOR GOOD DENDRITIC SNOW GROWTH. AS A
RESULT...FLAKES WILL BE SMALL AND ACCUMS SHOULD BE HELD IN
CHECK...AND WILL CONTINUE TO GO WITH 1-3 INCH AMOUNTS TONIGHT IN THE
SNOW BELT OF N-C WISCONSIN. LITTLE TO NO ACCUM ELSEWHERE.
BIGGER IMPACTS WILL LIKELY BE WIND RELATED. STRONG DESCENT
IMMEDIATELY BEHIND THE FRONT IN A REGION OF STRONG COLD
ADVECTION...STEEPENING LOW LEVEL LAPSE RATES...AND GOOD ISALLABARIC
PUSH WILL CREATE STRONG GUSTY WEST TO NORTHWEST WINDS THAT SHOULD
APPROACH OR JUST EXCEED WIND ADVISORY CRITERIA LATE THIS AFTERNOON
AND THROUGH THE EVENING. STRONGEST WINDS IN THE MIXED LAYER OF
45-50KTS ARE PROGGED TO OCCUR OVER CENTRAL AND EAST-CENTRAL
WISCONSIN WHERE THE CURRENT WIND ADVISORY RESIDES...SO PLACEMENT OF
HEADLINES LOOK GOOD. THE GUSTY WINDS SEEM TO BE RUNNING AN HOUR OR
TWO LATE...AND WILL LIKELY HAVE TO WAIT UNTIL THE COLDER AIR ALOFT
ARRIVES TO STEEPEN THE LOW LEVEL LAPSE RATES FOR THE GUSTY WINDS TO
OCCUR...LIKELY IN THE 22-02Z TIME PERIOD. WILL KEEP HEADLINE TIMING
STATUS QUO. THE STRONG PRESSURE RISES SHIFT TO THE EAST BY
MIDNIGHT...AND WIND GUSTS SHOULD BE SUBSIDING BY THIS TIME. AS A
RESULT...STILL THINK THE EVENING OR MIDNIGHT CREW WILL BE ABLE TO
END WIND HEADLINES EARLY. THE COMBO OF GUSTY NW WINDS AND INCOMING
ARCTIC AIR WILL CREATE WIND CHILL READINGS OF 20-25 DEGREES BELOW
ZERO OVER CENTRAL AND NORTH-CENTRAL WISCONSIN LATE TONIGHT.
SUNDAY...ARCTIC AIR WILL CONTINUE TO POUR ACROSS THE REGION ON
SUNDAY. NORTHWEST WINDS WILL CONTINUE TO PRODUCE LAKE EFFECT SNOW
SHOWERS IN THE SNOW BELTS...BUT WINDS DO BACK A BIT SO SNOW SHOWERS
SHOULD BE GRADUALLY DIMINISHING OVER THE COURSE OF THE MORNING. AIR
WILL REMAIN TOO COLD FOR DENDRITIC SNOW GROWTH SO NOT EXPECTING MUCH
ACCUMS. OTHERWISE...STEEP LOW LEVEL LAPSE RATES AND FLOW OFF LAKE
SUPERIOR SHOULD KEEP SKIES PARTLY TO MOSTLY CLOUDY. TEMPS IN THE
SINGLE DIGITS TO LOWER TEENS.
LONG TERM...SUNDAY NIGHT THROUGH NEXT SATURDAY. DURATION OF THE
ARCTIC BLAST OF AIR THIS WEEK ALONG WITH LIKELY ADDITIONAL WIND
CHILL HEADLINES WILL BE THE PRIMARY ISSUE FOR THE FIRST HALF OF
THE NEW WEEK. ANOTHER CLIPPER SYSTEM IS PROGGED TO DROP INTO THE
REGION AROUND THURSDAY FOLLOWED WITH A REINFORCING BUT MILDER
AND PERHAPS BRIEFER SHOT OF ARCTIC AIR. SOME MDM RANGE MODELS ARE
INDICATING A MODERATING TREND LATER NEXT WEEKEND.
ADDITIONAL WIND CHILL HEADLINES WILL LIKELY BE POSTED LATER THIS
WEEKEND AS THE SATURDAY NIGHT HEADLINES EXPIRE. FORECAST TEMPS
SUGGEST THE COLDEST AIR ARRIVES LATER MONDAY WITH SOME CURRENT
VALUES APPROACHING WIND CHILL WARNING CRITERIA MONDAY NIGHT.
TYPICAL WITH THE VERY COLD PATTERNS...MODELS LIKELY OVERDOING THE
COVERAGE OF CLOUDS. WILL TONE DOWN CLOUDS OVER MOST LOCATIONS
EXCEPT FOR AREAS JUST DOWNSTREAM FROM LAKE SUPERIOR.
LAKE EFFECT SNOWS EXPECTED OVER FAR NORTH CENTRAL WISCONSIN WITH
THE COLD AIR INTRUSION. BUT APPEARS TO BE LIMITED AT THIS TIME
DUE TO THE DRY AIR MASS...FALLING INVERSION HEIGHTS...AND A BIT
TOO WESTERLY WIND DIRECTION.
TEMPS TO MODERATE TO NEAR SEASONAL LEVELS LATER THIS WEEK WITH A
CLIPPER SYSTEM DROPPING SOUTH INTO THE NORTHERN AND CENTRAL PLAINS
THURSDAY BEFORE PHASING WITH SOME SOUTHERN STREAM ENERGY THURSDAY
NIGHT. GFS IS INDICATING A POSSIBLE ADVISORY SNOW OVER THE SOUTH
HALF OR THIRD OF THE STATE THURSDAY NIGHT WITH THIS PHASED SYSTEM.
WILL GLANCE AT THE ECMWF THIS AFTERNOON TOO SEE IF A SIMILAR
TREND IN ORDER TO MAKE ANY ADJUSTMENTS...BUT GOING FORECAST THAT
FAR OUT REASONABLE.
&&
.AVIATION...FOR 06Z TAF ISSUANCE. IMPROVING CONDITIONS
EXPECTED...EXCEPT IN THE SNOWBELT. THINK THE LOW CLDS WL ERODE
PRETTY QUICKLY LATER IN THE NGT ONCE DRY ARCTIC AIR BECOMES
ESTABLISHED ACRS THE AREA.
&&
.GRB WATCHES/WARNINGS/ADVISORIES...
WIND ADVISORY UNTIL 3 AM CST SUNDAY FOR WIZ038>040-048>050.
WIND ADVISORY UNTIL MIDNIGHT CST TONIGHT FOR WIZ030-031-035>037-
045.
WIND CHILL ADVISORY UNTIL 9 AM CST SUNDAY FOR WIZ010-011-018-019-
030-035-036.
WIND ADVISORY UNTIL 6 AM CST SUNDAY FOR WIZ022.
WINTER WEATHER ADVISORY UNTIL 9 AM CST SUNDAY FOR WIZ005.
&&
$$
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
635 AM EST SUN JAN 20 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 512 AM EST SUN JAN 20 2013
00Z RAOBS/LATEST WV IMAGERY AND RUC ANALYSIS SHOW HI AMPLITUDE UPR
TROF DOMINATING MOST OF CNTRL AND ERN NAMERICA DOWNWIND OF RDG ALONG
THE W COAST. COLDEST AIRMASS OF THE SEASON HAS SURGED INTO THE UPR
LKS IN THE WAKE OF POTENT SHRTWV/SFC LO NOW MOVING INTO SE ONTARIO
ON THE HEELS OF NW WINDS GUSTS TO ARND 50KT AS OBSVD AT SOME OF THE
HIER MARINE PLATFORMS. BUT WITH PASSAGE OF MAIN PRES RISE CENTER
EARLY THIS MRNG...THE SHARP CYC NW FLOW IS BEGINNING TO WEAKEN. 00Z
H85/H5 TEMPS WERE AS LO AS -25C/-40C AT YPL. NO SURPRISE THIS
INCOMING AIRMASS IS ALSO QUITE DRY WITH PWATS AOB 0.10 INCH. BUT
PASSAGE OF THIS FRIGID AIRMASS OVER THE RELATIVE WARM WATERS OF LK
SUP HAS RESULTED IN PLENTY OF LK CLDS AND LES...PRIMARILY IN THE NW
WIND SN BELTS E OF MQT AND OVER THE W. EVEN THOUGH WINDS ARE
BEGINNING TO DIMINISH...LINGERING GUSTY WINDS ARE BLOWING THE FINE
SN FLAKES AND RESULTING IN SHAPRLY REDUCED VSBY AS LO AS 1/4SM AT
SOME PLACES. TWO MORE SHRTWVS ARE DIGGING SEWD THRU SCNTRL CANADA
IN THE NW FLOW ALF ON CYC SIDE OF SHARP UPR JET AXIS ON THE WRN
FLANK OF THE DEEP TROF. OF THESE TWO...THE ONE FARTHER W IN
ALBERTA/SASKATCHEWAN LOOKS THE MOST IMPRESSIVE WITH 100KT H5 JET MAX
SHOWN IN NE BRITISH COLUMBIA AT 00Z.
TODAY...AS DEEP SHRTWV/SFC LO TO THE E EXIT FARTHER AWAY...PRES
GRADIENT WL SLACKEN AND WINDS DIMINISH. BUT LES WL CONTINUE MAINLY
IN THE NW WIND SN BELTS WITH ARRIVAL OF COLDER AIR/H85 TEMPS FALLING
TOWARD -25C OVER THE W BY 00Z DESPITE SOME MID LVL DRYING/
STRENGTHENING INVRN ARND 5K FT OVER THE W BUT AS HI AS 7-8FT OVER
THE E. THE LO H85 TEMPS WL LIMIT SN GROWTH AND RESULT IN FINE SN
FLAKES. THIS EFFECT SHOULD BE MAGNIFIED WITH SHORTER FETCH/LESS
MOISTENING OVER THE W BUT MITIGATED A BIT OVER THE E WITH LONGER
FETCH LENGTH. ALTHOUGH WINDS WL DIMINISH... SOME BLSN WL CONT
ESPECIALLY IN OPEN AREAS NEAR LK SUP AS THE FINE FLAKES WL BE BLOWN
EFFICIENTLY. WITH ARRIVAL OF FIRST OF 2 SHRTWVS UPSTREAM/
ACCOMPANYING DPVA...LLVL FLOW IS PROGGED TO BACK A BIT THIS
AFTN...WITH SOME MID LVL MOISTENING/INCRSG CONVECTIVE DEPTH SHOWING
UP AGAIN BY LATE THIS AFTN OVER THE W. EXPECT LTL DIURNAL RISE IN
TEMP WITH SURGE OF LLVL COLD AIR.
TONIGHT...2ND SHRTWV UPSTREAM/ACCOMPANYING DPVA ARE PROGGED TO
ARRIVE...WITH WEAKENING AND RISING INVRN/DEEPENING MSTR. AS CYC WNW
FLOW SHARPENS AS WELL...EXPECT INCRSG INTENSITY OF SHSN/BLSN. BULK
OF NUMERICAL MODELS SHOW SHARPEST LLVL CNVGC NEAR ONTONAGON COUNTY
AND IN AREAS NEAR LK SUP E OF MUNISING DUE TO LAND BREEZE EFFECTS
AND PERSISTENT LK INDUCED TROFFING OVER ERN LK SUP. WL FOCUS HIER
POPS/SN AMOUNTS IN THESE AREAS...ESPECIALLY OVER THE E WHERE LONGER
FETCH/MORE LK WARMING/MOISTENING WL IMPROVE SN/WATER RATIOS.
ALTHOUGH THE HEAVIER SHSN MIGHT DRIFT OUT OF NRN SCHOOLCRAFT COUNTY
LATE TNGT WITH BACKING FLOW...OPTED TO KEEP GOING WARNING FOR THE
ERN CWA GOING THRU 12Z MON. EXPECTED SN FALL OVER ONTONAGON COUNTY
LOOKS AT 4 TO 6 INCHES. SINCE THIS IS A MARGINAL ADVY AMOUNT AND
THERE IS LIKELY TO BE A BREAK IN THE SHSN/BLSN INTENSITY TODAY FOR
AT LEAST A TIME...DECIDED NOT TO EXTEND THE HEADLINE FOR ONTONAGON
COUNTY INTO TNGT. ANOTHER CONCERN WL BE POTENTIAL FOR AT LEAST ADVY
THRESHOLD WIND CHILLS AS THIS SHRTWV DRAGS H85 TEMPS AS LO AS -30C
TO IWD BY 12Z MON. SINCE THE H925 FLOW WL BE 280-290 DEGREES...CAD
WL ALLOW FOR MORE MIXING OF THE 20-25KT H925 WINDS...AND NEAR SFC
FLOW WL BACK FURTHER AND ALLOW FOR ADVECTION OF MORE UNMODIFIED
ARCTIC AIR DUE TO LAND BREEZE COMPONENT WITHIN BITTERLY COLD
AIRMASS...EXPECT WIND CHILLS TO FALL INTO THE ADVY RANGE AT LEAST
NEAR THE WI BORDER.
.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 512 AM EST SUN JAN 20 2013
GOING INTO MON...A TROUGH WILL ROTATE THROUGH THE CWA DURING THE
DAY. MODELS SHOW THAT DYNAMICS WITH THE TROUGH WILL NOT BRING MUCH
IF ANYTHING IN THE WAY OF SYNOPTIC SNOW...BUT WILL ACT TO INTENSIFY
NW WIND LES AND CAUSE THE SFC TROUGH OVER ERN LAKE SUPERIOR TO CLOSE
OFF. HIGHER RES MODELS SUGGEST THAT THE LOW WILL FOCUS LES BANDS
INTO A MORE DOMINANT BAND MOVING ONSHORE ACROSS ALGER AND/OR LUCE
COUNTIES...DEPENDING ON MESOSCALE CONDITIONS THAT WILL HAVE TO BE
DETERMINED MUCH CLOSER TO THE TIME OF OCCURRENCE. GIVEN 725MB
INVERSION TOP TEMPERATURES AROUND -35C AND LAKE WATER TEMPS AROUND
2C...LAKE INDUCED EQUILIBRIUM LEVELS OF 12-15KFT SHOULD BE REALIZED
OVER ERN LAKE SUPERIOR. THE DGZ WILL BE VERY LOW...SO SLR/S WILL NOT
BE AS HIGH AS THE COULD BE IN WARMER CONDITIONS. EVEN SO...IF A
HEAVIER BAND DOES FORM...SNOWFALL RATES COULD APPROACH AN INCH AN
HOUR UNDER THE BAND. OVER WRN LAKE SUPERIOR...INVERSION TOPS WILL
NOT BE AS HIGH FARTHER AWAY FROM THE TROUGH.
THE REALLY COLD AIR /850MB TEMPS -27C TO -30C/ BEGINS TO PUSH E LATE
TUE...SO THE COLDEST SFC TEMPS OF THE SEASON /AREA WIDE/ WILL BE MON
THROUGH TUE NIGHT...WITH A CONCERN OF WIND CHILLS. WIND CHILL
ADVISORY CRITERIA IS WIND CHILLS LESS THAN -25F WITH WINDS AT LEAST
10MPH...WHICH SHOULD BE REACHED OVER PORTIONS OF THE WRN HALF OF THE
U.P. SUN NIGHT THROUGH MON AND AGAIN TUE NIGHT /MON NIGHT THE WINDS
ARE FORECAST TO BE BELOW THE 10MPH CRITERIA/. WARNING CRITERIA OF
-35F SHOULD BE HARDER TO ACHIEVE...WITH THE BEST CHANCE OF
OCCURRENCE SUN NIGHT INTO MON MORNING AND MON NIGHT INTO TUE MORNING
OVER THE FAR W. COLDEST ACTUAL TEMPS LOOK TO BE MON NIGHT OVER
PORTIONS OF GOGEBIC AND IRON COUNTIES WITH A LOW FORECAST OF -20F.
DECIDED TO ISSUE WIND CHILL ADVISORY FOR THE FAR W MON.
LOW LEVEL TEMPS GENERALLY WARM SLOWLY TO -15C TO -20C BY SAT WITH NW
LOW LEVEL WINDS THROUGH MOST OF THE PERIOD. A SHORTWAVE LOOKS TO
MOVE THROUGH ON WED...SO LES SHOULD BE INTENSIFIED THEN...BUT
OTHERWISE MORE RIDGING WORKS INTO THE AREA THROUGH THE REST OF THE
PERIOD...MAKING FOR MORE HOSTILE CONDITIONS FOR LES THU THROUGH SAT.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z MONDAY MORNING)
ISSUED AT 634 AM EST SUN JAN 20 2013
EXPECT PREDOMINANT IFR TO LIFR CONDITIONS TO DOMINATE CMX THIS FCST
PERIOD WITH GUSTY NW FLOW OF ARCTIC AIR BRINGING PERSISTENT SHSN/
BLSN. ALTHOUGH IFR WX WL PREDOMINATE AT IWD THIS MRNG...EXPECT
IMPROVEMENT AS THE LLVL FLOW SLOWLY BACKS TOWARD THE W AND BRINGS
DRIER AIR/PREDOMINANT MVFR CONDITIONS. ALTHOUGH THERE MAY BE LINGERING
MVFR WX AT SAW THIS MRNG...VFR CONDITIONS SHOULD DOMINATE THERE BY
THIS AFTN WITH DOWNSLOPING FLOW AND DRY ADVECTION.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 512 AM EST SUN JAN 20 2013
EXPECT NW GALES TO 40 KTS THIS MORNING OVER MAINLY THE E HALF TO
DIMINISH BY EARLY AFTERNOON AS LO PRES OVER SE CANADA CONTINUES TO
MOVE FARTHER TO THE E. BUT WITH ARCTIC AIR DOMINATING INTO MID
WEEK...THERE WILL BE PERIODS OF HEAVY FREEZING SPRAY EVEN THOUGH THE
NW WINDS WILL BE MAINLY IN THE 15 TO 30 KT RANGE. THE ARRIVAL OF A
WEAKER PRES GRADIENT/LIGHTER WINDS BY LATER WED/THU WILL FINALLY END
THE THREAT OF HEAVY FREEZING SPRAY.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
LAKE EFFECT SNOW WARNING UNTIL 7 AM EST MONDAY FOR MIZ006-007-
085.
LAKE EFFECT SNOW ADVISORY UNTIL 1 PM EST /NOON CST/ THIS
AFTERNOON FOR MIZ001>003-009.
WIND CHILL ADVISORY FROM 3 AM TO 6 PM CST MONDAY FOR MIZ009.
LAKE EFFECT SNOW ADVISORY UNTIL 7 AM EST THIS MORNING FOR MIZ005.
WIND CHILL ADVISORY FROM 4 AM EST /3 AM CST/ TO 1 PM EST /NOON
CST/ MONDAY FOR MIZ002-010.
LAKE SUPERIOR...
HEAVY FREEZING SPRAY WARNING UNTIL 7 PM EST TUESDAY FOR
LSZ245>251-265>267.
GALE WARNING UNTIL 1 PM EST THIS AFTERNOON FOR LSZ245>251-
265>267.
HEAVY FREEZING SPRAY WARNING UNTIL 7 PM EST /6 PM CST/ MONDAY
FOR LSZ162-240>244-263-264.
GALE WARNING UNTIL 11 AM EST THIS MORNING FOR LSZ244-264.
GALE WARNING UNTIL 7 AM EST /6 AM CST/ THIS MORNING FOR LSZ162-
240>243-263.
LAKE MICHIGAN...
HEAVY FREEZING SPRAY WARNING UNTIL 9 AM EST THIS MORNING FOR
LMZ248-250.
GALE WARNING UNTIL 7 AM EST THIS MORNING FOR LMZ221-248-250.
&&
$$
SHORT TERM...KC
LONG TERM...TITUS
AVIATION...KC
MARINE...KC
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
513 AM EST SUN JAN 20 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 512 AM EST SUN JAN 20 2013
00Z RAOBS/LATEST WV IMAGERY AND RUC ANALYSIS SHOW HI AMPLITUDE UPR
TROF DOMINATING MOST OF CNTRL AND ERN NAMERICA DOWNWIND OF RDG ALONG
THE W COAST. COLDEST AIRMASS OF THE SEASON HAS SURGED INTO THE UPR
LKS IN THE WAKE OF POTENT SHRTWV/SFC LO NOW MOVING INTO SE ONTARIO
ON THE HEELS OF NW WINDS GUSTS TO ARND 50KT AS OBSVD AT SOME OF THE
HIER MARINE PLATFORMS. BUT WITH PASSAGE OF MAIN PRES RISE CENTER
EARLY THIS MRNG...THE SHARP CYC NW FLOW IS BEGINNING TO WEAKEN. 00Z
H85/H5 TEMPS WERE AS LO AS -25C/-40C AT YPL. NO SURPRISE THIS
INCOMING AIRMASS IS ALSO QUITE DRY WITH PWATS AOB 0.10 INCH. BUT
PASSAGE OF THIS FRIGID AIRMASS OVER THE RELATIVE WARM WATERS OF LK
SUP HAS RESULTED IN PLENTY OF LK CLDS AND LES...PRIMARILY IN THE NW
WIND SN BELTS E OF MQT AND OVER THE W. EVEN THOUGH WINDS ARE
BEGINNING TO DIMINISH...LINGERING GUSTY WINDS ARE BLOWING THE FINE
SN FLAKES AND RESULTING IN SHAPRLY REDUCED VSBY AS LO AS 1/4SM AT
SOME PLACES. TWO MORE SHRTWVS ARE DIGGING SEWD THRU SCNTRL CANADA
IN THE NW FLOW ALF ON CYC SIDE OF SHARP UPR JET AXIS ON THE WRN
FLANK OF THE DEEP TROF. OF THESE TWO...THE ONE FARTHER W IN
ALBERTA/SASKATCHEWAN LOOKS THE MOST IMPRESSIVE WITH 100KT H5 JET MAX
SHOWN IN NE BRITISH COLUMBIA AT 00Z.
TODAY...AS DEEP SHRTWV/SFC LO TO THE E EXIT FARTHER AWAY...PRES
GRADIENT WL SLACKEN AND WINDS DIMINISH. BUT LES WL CONTINUE MAINLY
IN THE NW WIND SN BELTS WITH ARRIVAL OF COLDER AIR/H85 TEMPS FALLING
TOWARD -25C OVER THE W BY 00Z DESPITE SOME MID LVL DRYING/
STRENGTHENING INVRN ARND 5K FT OVER THE W BUT AS HI AS 7-8FT OVER
THE E. THE LO H85 TEMPS WL LIMIT SN GROWTH AND RESULT IN FINE SN
FLAKES. THIS EFFECT SHOULD BE MAGNIFIED WITH SHORTER FETCH/LESS
MOISTENING OVER THE W BUT MITIGATED A BIT OVER THE E WITH LONGER
FETCH LENGTH. ALTHOUGH WINDS WL DIMINISH... SOME BLSN WL CONT
ESPECIALLY IN OPEN AREAS NEAR LK SUP AS THE FINE FLAKES WL BE BLOWN
EFFICIENTLY. WITH ARRIVAL OF FIRST OF 2 SHRTWVS UPSTREAM/
ACCOMPANYING DPVA...LLVL FLOW IS PROGGED TO BACK A BIT THIS
AFTN...WITH SOME MID LVL MOISTENING/INCRSG CONVECTIVE DEPTH SHOWING
UP AGAIN BY LATE THIS AFTN OVER THE W. EXPECT LTL DIURNAL RISE IN
TEMP WITH SURGE OF LLVL COLD AIR.
TONIGHT...2ND SHRTWV UPSTREAM/ACCOMPANYING DPVA ARE PROGGED TO
ARRIVE...WITH WEAKENING AND RISING INVRN/DEEPENING MSTR. AS CYC WNW
FLOW SHARPENS AS WELL...EXPECT INCRSG INTENSITY OF SHSN/BLSN. BULK
OF NUMERICAL MODELS SHOW SHARPEST LLVL CNVGC NEAR ONTONAGON COUNTY
AND IN AREAS NEAR LK SUP E OF MUNISING DUE TO LAND BREEZE EFFECTS
AND PERSISTENT LK INDUCED TROFFING OVER ERN LK SUP. WL FOCUS HIER
POPS/SN AMOUNTS IN THESE AREAS...ESPECIALLY OVER THE E WHERE LONGER
FETCH/MORE LK WARMING/MOISTENING WL IMPROVE SN/WATER RATIOS.
ALTHOUGH THE HEAVIER SHSN MIGHT DRIFT OUT OF NRN SCHOOLCRAFT COUNTY
LATE TNGT WITH BACKING FLOW...OPTED TO KEEP GOING WARNING FOR THE
ERN CWA GOING THRU 12Z MON. EXPECTED SN FALL OVER ONTONAGON COUNTY
LOOKS AT 4 TO 6 INCHES. SINCE THIS IS A MARGINAL ADVY AMOUNT AND
THERE IS LIKELY TO BE A BREAK IN THE SHSN/BLSN INTENSITY TODAY FOR
AT LEAST A TIME...DECIDED NOT TO EXTEND THE HEADLINE FOR ONTONAGON
COUNTY INTO TNGT. ANOTHER CONCERN WL BE POTENTIAL FOR AT LEAST ADVY
THRESHOLD WIND CHILLS AS THIS SHRTWV DRAGS H85 TEMPS AS LO AS -30C
TO IWD BY 12Z MON. SINCE THE H925 FLOW WL BE 280-290 DEGREES...CAD
WL ALLOW FOR MORE MIXING OF THE 20-25KT H925 WINDS...AND NEAR SFC
FLOW WL BACK FURTHER AND ALLOW FOR ADVECTION OF MORE UNMODIFIED
ARCTIC AIR DUE TO LAND BREEZE COMPONENT WITHIN BITTERLY COLD
AIRMASS...EXPECT WIND CHILLS TO FALL INTO THE ADVY RANGE AT LEAST
NEAR THE WI BORDER.
.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 512 AM EST SUN JAN 20 2013
GOING INTO MON...A TROUGH WILL ROTATE THROUGH THE CWA DURING THE
DAY. MODELS SHOW THAT DYNAMICS WITH THE TROUGH WILL NOT BRING MUCH
IF ANYTHING IN THE WAY OF SYNOPTIC SNOW...BUT WILL ACT TO INTENSIFY
NW WIND LES AND CAUSE THE SFC TROUGH OVER ERN LAKE SUPERIOR TO CLOSE
OFF. HIGHER RES MODELS SUGGEST THAT THE LOW WILL FOCUS LES BANDS
INTO A MORE DOMINANT BAND MOVING ONSHORE ACROSS ALGER AND/OR LUCE
COUNTIES...DEPENDING ON MESOSCALE CONDITIONS THAT WILL HAVE TO BE
DETERMINED MUCH CLOSER TO THE TIME OF OCCURRENCE. GIVEN 725MB
INVERSION TOP TEMPERATURES AROUND -35C AND LAKE WATER TEMPS AROUND
2C...LAKE INDUCED EQUILIBRIUM LEVELS OF 12-15KFT SHOULD BE REALIZED
OVER ERN LAKE SUPERIOR. THE DGZ WILL BE VERY LOW...SO SLR/S WILL NOT
BE AS HIGH AS THE COULD BE IN WARMER CONDITIONS. EVEN SO...IF A
HEAVIER BAND DOES FORM...SNOWFALL RATES COULD APPROACH AN INCH AN
HOUR UNDER THE BAND. OVER WRN LAKE SUPERIOR...INVERSION TOPS WILL
NOT BE AS HIGH FARTHER AWAY FROM THE TROUGH.
THE REALLY COLD AIR /850MB TEMPS -27C TO -30C/ BEGINS TO PUSH E LATE
TUE...SO THE COLDEST SFC TEMPS OF THE SEASON /AREA WIDE/ WILL BE MON
THROUGH TUE NIGHT...WITH A CONCERN OF WIND CHILLS. WIND CHILL
ADVISORY CRITERIA IS WIND CHILLS LESS THAN -25F WITH WINDS AT LEAST
10MPH...WHICH SHOULD BE REACHED OVER PORTIONS OF THE WRN HALF OF THE
U.P. SUN NIGHT THROUGH MON AND AGAIN TUE NIGHT /MON NIGHT THE WINDS
ARE FORECAST TO BE BELOW THE 10MPH CRITERIA/. WARNING CRITERIA OF
-35F SHOULD BE HARDER TO ACHIEVE...WITH THE BEST CHANCE OF
OCCURRENCE SUN NIGHT INTO MON MORNING AND MON NIGHT INTO TUE MORNING
OVER THE FAR W. COLDEST ACTUAL TEMPS LOOK TO BE MON NIGHT OVER
PORTIONS OF GOGEBIC AND IRON COUNTIES WITH A LOW FORECAST OF -20F.
DECIDED TO ISSUE WIND CHILL ADVISORY FOR THE FAR W MON.
LOW LEVEL TEMPS GENERALLY WARM SLOWLY TO -15C TO -20C BY SAT WITH NW
LOW LEVEL WINDS THROUGH MOST OF THE PERIOD. A SHORTWAVE LOOKS TO
MOVE THROUGH ON WED...SO LES SHOULD BE INTENSIFIED THEN...BUT
OTHERWISE MORE RIDGING WORKS INTO THE AREA THROUGH THE REST OF THE
PERIOD...MAKING FOR MORE HOSTILE CONDITIONS FOR LES THU THROUGH SAT.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT)
ISSUED AT 1209 AM EST SUN JAN 20 2013
GUSTY NW WINDS WILL CONTINUE INTO THE EARLY OVERNIGHT AT ALL TAF
SITES IN THE WAKE OF A CLIPPER SYSTEM AND ASSOCIATED COLD FRONT.
EXPECT IFR/LIFR CONDITIONS AT ALL SITES IN LAKE EFFECT SNOW AND
BLOWING SNOW INTO THE EARLY OVERNIGHT. CONDITIONS SHOULD
SLOWLY IMPROVE LATE TONIGHT INTO SUNDAY MORNING AS THE WIND DIES
DOWN. CONDITIONS AT KSAW SHOULD RETURN TO VFR SUNDAY AFTERNOON AS
WINDS BACK WNW AND LAKE CLOUDS PUSH EAST. CONDITIONS AT KIWD AND
KCMX WILL AGAIN LOWER DOWN TO IFR/LIFR LATE SUNDAY AFTERNOON AND
EVENING AS CONDITIONS OVER LAKE SUPERIOR BECOME MORE UNSTABLE AND
MOISTURE DEEPENS ALLOWING FOR MORE INTENSE LAKE EFFECT SNOW BANDS TO
FORM.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 512 AM EST SUN JAN 20 2013
EXPECT NW GALES TO 40 KTS THIS MORNING OVER MAINLY THE E HALF TO
DIMINISH BY EARLY AFTERNOON AS LO PRES OVER SE CANADA CONTINUES TO
MOVE FARTHER TO THE E. BUT WITH ARCTIC AIR DOMINATING INTO MID
WEEK...THERE WILL BE PERIODS OF HEAVY FREEZING SPRAY EVEN THOUGH THE
NW WINDS WILL BE MAINLY IN THE 15 TO 30 KT RANGE. THE ARRIVAL OF A
WEAKER PRES GRADIENT/LIGHTER WINDS BY LATER WED/THU WILL FINALLY END
THE THREAT OF HEAVY FREEZING SPRAY.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
LAKE EFFECT SNOW WARNING UNTIL 7 AM EST MONDAY FOR MIZ006-007-
085.
LAKE EFFECT SNOW ADVISORY UNTIL 1 PM EST /NOON CST/ THIS
AFTERNOON FOR MIZ001>003-009.
WIND CHILL ADVISORY FROM 3 AM TO 6 PM CST MONDAY FOR MIZ009.
LAKE EFFECT SNOW ADVISORY UNTIL 7 AM EST THIS MORNING FOR MIZ005.
WIND CHILL ADVISORY FROM 4 AM EST /3 AM CST/ TO 1 PM EST /NOON
CST/ MONDAY FOR MIZ002-010.
LAKE SUPERIOR...
HEAVY FREEZING SPRAY WARNING UNTIL 7 PM EST TUESDAY FOR
LSZ245>251-265>267.
GALE WARNING UNTIL 1 PM EST THIS AFTERNOON FOR LSZ245>251-
265>267.
HEAVY FREEZING SPRAY WARNING UNTIL 7 PM EST /6 PM CST/ MONDAY
FOR LSZ162-240>244-263-264.
GALE WARNING UNTIL 11 AM EST THIS MORNING FOR LSZ244-264.
GALE WARNING UNTIL 7 AM EST /6 AM CST/ THIS MORNING FOR LSZ162-
240>243-263.
LAKE MICHIGAN...
HEAVY FREEZING SPRAY WARNING UNTIL 9 AM EST THIS MORNING FOR
LMZ248-250.
GALE WARNING UNTIL 7 AM EST THIS MORNING FOR LMZ221-248-250.
&&
$$
SHORT TERM...KC
LONG TERM...TITUS
AVIATION...VOSS
MARINE...KC
AREA FORECAST DISCUSSION
NWS HASTINGS NE
603 AM CST SUN JAN 20 2013
.AVIATION.../12Z GRI TAF THROUGH 12Z MONDAY MORNING/
EARLY THIS MRNG: VFR WITH MULTIPLE LAYERS OF MID-HIGH CIGS ABOVE
15K FT. HOWEVER...SATELLITE AND SFC OBS INDICATE IFR/LOW-END MVFR
STRATUS DEVELOPING ALONG A FRONT 100 SM W OF GRI. HAVE INDICATED
SCT015 BEGINNING AT 12Z TO ACCOUNT FOR WHAT WE BELIEVE WILL BE AN
EVENTUAL DECAY TO MVFR CIGS.
TODAY: WITH THE ON-GOING DEVELOPMENT OF STRATUS...CONFIDENCE HAS
INCREASED IN MVFR CIGS AND LATEST FCST SOUNDINGS ARE SUPPORTIVE.
SO MVFR CIGS ARE NOW IN THE TAF. THERE IS A LOW PROB FOR A PERIOD
OF IFR CIGS. WINDS WILL REMAIN LIGHT AND VARIABLE UNTIL ARCTIC
FROPA...WITHIN AN HOUR OR TWO OF 19Z. AFTER FROPA...EXPECT A WSHFT
TO N WITH GUSTS UP TO 20 KTS. THERE IS ALSO POTENTIAL FOR CIGS TO
IMPROVE TO 3500 FT.
TNGT: FCST SOUNDINGS CONTINUE TO INDICATE POTENTIAL FOR MVFR CIGS.
NOT ALL FCST GUIDANCE AGREES WHICH LOWERS CONFIDENCE. SOME
GUSTINESS CONTINUES INTO THE EVNG...THEN NNW WINDS SHOULD SETTLE
AROUND 8 KTS.
CIG CONFIDENCE: AVERAGE
VSBY CONFIDENCE: HIGH
WIND CONFIDENCE: AVERAGE. EXACT TIME OF FROPA UNCERTAIN. ALSO
UNSURE OF DEGREE OF GUSTINESS POST-FROPA.
WX CONFIDENCE: HIGH
&&
.PREV DISCUSSION... /ISSUED 414 AM CST SUN JAN 20 2013/
SHORT TERM...TODAY THROUGH TUESDAY NIGHT. PRIMARY FORECAST
CONCERN LIES WITH TEMPERATURES.
QUIET CONDITIONS REMAIN IN PLACE ACROSS THE REGION EARLY THIS
MORNING...WITH SATELLITE AND UPPER AIR PROFILER DATA SHOWING
NORTHWESTERLY FLOW IN PLACE. RIDGING CONTINUES ALONG THE WEST
COAST...WHILE A COUPLE OF DISTURBANCES WORK THEIR WAY THROUGH THE
NWRLY FLOW...ONE OVER THE GREAT LAKES REGION AND THE OTHER OVER SC
CANADA. AT THE SURFACE...HIGH PRESSURE CONTINUES TO SLIDE SOUTH
OUT OF THE DAKOTAS INTO THE AREA...BEHIND A COLD FRONT WHICH
PASSED THROUGH THE REGION LATE SAT AFTN/EVENING. WITH TIME...WINDS
HAVE GRADUALLY BECOME MORE EASTERLY ACROSS THE CWA...AND HAVE
DIMINISHED IN SPEED.
LOOKING AT THE REST OF TODAY AND INTO MONDAY...THE MAIN STORY LIES
WITH THE PASSAGE OF YET ANOTHER COLD FRONT...AND ITS AFFECT ON
TEMPERATURES. MODELS REMAIN IN GOOD AGREEMENT SHOWING THE ABOVE
MENTIONED UPPER LEVEL DISTURBANCE OVER SC CANADA CONTINUING TO
SLIDE SOUTHEAST THROUGH THE DAY TODAY...WITH THE TIMING OF THE
ACCOMPANYING SFC COLD FRONT/NORTHWESTERLY WINDS STILL EXPECTED TO
PASS THROUGH THE CWA DURING THE AFTERNOON HOURS. THE TIMING MAKES
TEMPERATURES TODAY PRETTY DIFFICULT...ESP WITH MODELS/GUIDANCE NOT
IN VERY GOOD AGREEMENT...MAINLY FOR THOSE NORTHWESTERN PORTIONS OF
THE CWA...WHICH WILL PROB SEE THEIR HIGHS CLOSER TO MIDDAY/EARLY
AFTN VS MID AFTN FURTHER SOUTH. OVERALL DIDNT MAKE MANY CHANGES TO
THE INHERITED FORECAST...WHICH CONTINUES TO CALL FOR GENERALLY MID
30S ACROSS SC NEB...WITH LOWER 40S IN NC KS. CERTAINLY SOMETHING
FOR THE DAYSHIFT TO KEEP AN EYE ON.
AS FAR AS THE POSSIBILITY OF FLURRIES GOES...DECIDED TO KEEP THE
MENTION OUT OF THE FORECAST. AS THAT DISTURBANCE SWINGS SOUTH...IT
WILL BRING ALONG MORE CLOUD COVER AND COLDER TEMPERATURES...AND
WHILE MODELS DO SHOW SOME BATCHES OF INCREASED LOWER LEVEL /BELOW
700MB/ MOISTURE MOVING INTO THE REGION...MAINLY THIS
AFTERNOON...THERE IS ALSO PRETTY GOOD AGREEMENT WITH KEEPING THE
BETTER RH AND COLDER TEMPS MORE FAVORABLE FOR FLURRIES
NORTH/NORTHEAST OF THE CWA...BARELY. THE OPER NAM/GFS/EC CONTINUE
TO SHOW THE CWA DRY...AS DOES THE HRRR. THE RAP AND ONE RUN OF THE
4 KM SHOW PERHAPS THE FAR N/NE EDGE OF THE CWA MAYBE SEEING A
FEW...BUT AM GOING TO CONTINUE TO EXCLUDE THE MENTION.
REALLY THE BRUNT OF THE COLDER AIR HOLDS OFF FROM MOVING INTO THE
CWA UNTIL LATER TODAY AND MAINLY THIS EVENING/TONIGHT. AS HAS BEEN
THE CASE OVER THE PAST FEW DAYS...MODELS CONTINUE TO SHOW THE
MAIN AXIS OF THE TROUGH...AND THUS THE COLDEST AIR...SETTING UP
JUST EAST OF THE CWA TONIGHT/THROUGH MONDAY. WHILE THE CWA MAY
CATCH A BRIEF BREAK FROM CLOUD COVER TONIGHT...EXPECTING TO SEE
ADDITIONAL CLOUD COVER /MAINLY UPPER LEVEL/ STREAMING IN FROM THE
NORTHWEST...KEEPING MAINLY THE NORTHEASTERN HALF OF THE CWA UNDER
PARTLY/MOSTLY CLOUDY SKIES ON MONDAY. DIDNT MAKE ANY NOTABLE
CHANGES TO MONDAYS HIGHS...WHICH RANGE FROM THE LOWER 20S IN THE
NORTHEAST TO LOWER 30S IN THE SOUTHWEST. SURFACE HIGH PRESSURE
SLIDING IN FROM THE NORTHWEST WILL BRING FAIRLY LIGHT WINDS FOR
MOST LOCATIONS.
MONDAY NIGHT THROUGH TUESDAY...THE MAIN UPPER LEVEL TROUGH/COLDEST
AIR ALREADY STARTS ITS EASTWARD SHIFT MONDAY NIGHT...WHICH WILL
BRING A REBOUND IN TEMPS FOR TUESDAY. THE POSSIBILITY OF GETTING
CLIPPED IN THE NORTH BY MORE FLURRIES OR LIGHT SNOW WILL BE
SOMETHING TO CONSIDER WITH UPCOMING MODEL RUNS. CURRENTLY AM
KEEPING THE MENTION OUT OF THE FORECAST...WITH MODELS SHOWING THE
COLDER TEMPS AND BETTER POTENTIAL /MAINLY MONDAY NIGHT INTO THE
FIRST HALF OF TUESDAY/...DRIVEN BY A STRONG UPPER LEVEL JET
STREAK NOSING IN FROM THE N/NW...REMAINING ONCE AGAIN JUST OUTSIDE
THE N/NE EDGE OF THE CWA. WITH THE WARMER AIR STARTING TO BUILD
BACK IN FROM THE WEST...HIGHS CURRENTLY RANGE FROM THE UPPER 20S
IN THE NORTHEAST TO LOWER 40S IN THE WEST...AND SOME MODELS
SUGGEST THE WEST SHOULD BE WARMER. OVERNIGHT LOWS EXPECTED TO
REBOUND FROM THE SINGLE DIGITS/TEENS MONDAY NIGHT TO THE
TEENS/NEAR 20 TUESDAY NIGHT.
LONG TERM...(WEDNESDAY THRU SATURDAY)
THE MAIN STORY: BONE DRY PATTERN CONTINUES WITH RE-AMPLIFYING NW
FLOW STUNTING TEMP RECOVERY...BUT SIGNALS CONTINUE FOR SOME PRECIP
POTENTIAL VERY LATE THIS MONTH.
PATTERN: THE HIGHLY AMPLIFIED WRN N AMERICA RIDGE/ERN TROF WILL
MEET ITS DEMISE NEXT WEEK AS A PACIFIC SHRTWV TROF MOVES ONSHORE
IN THE PAC NW WED AND MOVES THRU THE RIDGE. AS THIS TROF MOVES
INTO THE LGWV TROF THU-FRI...THE PATTERN WILL RE-AMPLIFY
SOMEWHAT...CURBING OUR WARM-UP FRI-SAT. RIDGING THEN ADVANCES OVER
THE PLAINS NEXT WEEKEND...FOLLOWED BY LOWERING HGTS OVER WRN N
AMERICA THE LAST WEEK OF JAN...SUGGESTING A PERIOD OF STORMINESS
AND PCPN POTENTIAL.
MODELS: THERE IS GOOD AGREEMENT AMONGST THE 00Z EC/GFS/GEM ON THIS
SCENARIO THRU 00Z/SAT. THE ONE CAVEAT...THE OPERATIONAL 18Z/00Z GFS
ARE NOT AS AMPLIFIED WITH THE TEMPORARILY REINVIGORATED RIDING OVER
WRN N AMERICA. IN FACT...THE GFS ENSEMBLE MEAN IS CLOSER TO THE
MORE AMPLIFIED 12Z/00Z EC CYCLES. THIS FCST INCORPORATES
EC/GFS/GEM/HPC GUIDANCE THRU 00Z/SAT. BEYOND THAT ITS HPC/EC AND
EC/GFS ENSEMBLE MEANS.
TEMPS: ESSENTIALLY NEAR NORMAL THRU SAT WITH ONE DAY OF BELOW
NORMAL FRI.
HAZARDS: NONE ENVISIONED ATTM.
UPCOMING PCPN OPPORTUNITIES: NOTHING NOTABLE THRU AT LEAST SAT AND
PROBABLY TO MON 1/28. HOWEVER...ODDS ARE INCREASING FOR A MDT
PCPN EVENT AS WE CLOSE THE BOOKS ON JAN.
THE DAILY DETAILS...
WED: M/SUNNY. PROBABLY NEAR NORMAL TEMPS. LEE TROF INTENSIFIES
WITH TROF MOVING INTO PAC NW...AIDING IN MODEST TEMP RECOVERY.
TEMP CONFIDENCE GRAPHICS SHOW ABOVE NORMAL SPREAD IN TEMPS.
THU: P/CLOUDY. A DRY COLD FRONTAL PASSAGE IN THE PRE-DAWN HRS. LOW
PRES EJECTS OUT OF CO ACROSS KS/OK. SOME DIFF/S IN TIMING REMAIN
WITH THE EC/GEM FASTER AND MORE POTENT THAN THE GFS. THE 00Z EC
ENSEMBLES HAVE COME INTO MUCH BETTER AGREEMENT ON SLP SINCE ITS
12Z RUN. HPC IS IN AGREEMENT SO WE/LL ROLL WITH THIS SCENARIO.
ABOVE NORMAL UNCERTAINTY IN TEMPS.
THU HAS POTENTIAL TO BE A BREEZY DAY. HOWEVER...SOME BAGGINESS IN
THE PRES TROF OF A REINFORCING SHOT OF COLD AIR COULD MITIGATE.
THU NGT: ANOTHER PUSH OF COLDER AIR MOVES THRU AS THE SHRTWV TROF
PASSES...BUT THE WORST OF IT REMAINS OFF TO THE N AND E.
FRI: P/CLOUDY. ARCTIC HIGH PRES EXPANDS OVER THE MS VALLEY. IF THE
EC IS RIGHT ANOTHER WEAK LOW MOVES THRU DELIVERING ANOTHER PUSH OF
MARGINALLY COLD AIR. CONFIDENCE IS ABOVE NORMAL ON A COOL DOWN.
TEMPS PROBABLY CLOSE TO 10F BELOW NORMAL.
SAT: SUNNY AS YET ANOTHER ARCTIC HIGH EXPANDS OVER THE MS VALLEY.
HGTS BEGIN RISING AS BROAD RIDGING ADVANCES TOWARD THE PLAINS. WAA
BEGINS WITH A NEW LEE TROF DEVELOPING.
BEYOND SAT...
A VERY NICE WARM-UP COMMENCES SUN THAT COULD LINGER INTO EARLY THE
FOLLOWING WEEK 1/28-29 DEPENDENT ON HOW THE PATTERN SHAPES UP.
WE COULD SEE 1 OR 2 DAYS OF MUCH ABOVE NORMAL TEMPS (+10F OR
MORE). IF WE ROLL WITH THE OPERATIONAL EC AND THE EC/GFS ENSEMBLES
LATE THIS WEEK...THEN WE MUST GO SLOWER THAN THE OPERATIONAL GFS
FOR EARLY THE FOLLOWING WEEK. THE GREATER AMPLIFIED SCENARIO WILL
SLOW THINGS DOWN UPSTREAM. EITHER WAY...THE NEXT PAC TROF WILL DIG
INTO THE DESERT SW THE LAST WEEK OF JAN. THIS IS A FAVORABLE SETUP
FOR A DECENT PCPN EVENT HERE AND WITH THE LOW TRACKING S OF THE
FCST AREA...THIS COULD END UP BEING THE WINTRY VARIETY. HOPEFULLY
WE/LL HAVE TIME TO ENTRAIN GOOD MSTR AFTER MULTIPLE EPISODES OF
CONTINENTAL POLAR AIR HAVE PLUNGED INTO THE GULF.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
KS...NONE.
&&
$$
AVIATION...HALBLAUB
SHORT TERM...ADO
LONG TERM...HALBLAUB
AREA FORECAST DISCUSSION
NWS HASTINGS NE
414 AM CST SUN JAN 20 2013
.SHORT TERM...TODAY THROUGH TUESDAY NIGHT. PRIMARY FORECAST
CONCERN LIES WITH TEMPERATURES.
QUIET CONDITIONS REMAIN IN PLACE ACROSS THE REGION EARLY THIS
MORNING...WITH SATELLITE AND UPPER AIR PROFILER DATA SHOWING
NORTHWESTERLY FLOW IN PLACE. RIDGING CONTINUES ALONG THE WEST
COAST...WHILE A COUPLE OF DISTURBANCES WORK THEIR WAY THROUGH THE
NWRLY FLOW...ONE OVER THE GREAT LAKES REGION AND THE OTHER OVER SC
CANADA. AT THE SURFACE...HIGH PRESSURE CONTINUES TO SLIDE SOUTH
OUT OF THE DAKOTAS INTO THE AREA...BEHIND A COLD FRONT WHICH
PASSED THROUGH THE REGION LATE SAT AFTN/EVENING. WITH TIME...WINDS
HAVE GRADUALLY BECOME MORE EASTERLY ACROSS THE CWA...AND HAVE
DIMINISHED IN SPEED.
LOOKING AT THE REST OF TODAY AND INTO MONDAY...THE MAIN STORY LIES
WITH THE PASSAGE OF YET ANOTHER COLD FRONT...AND ITS AFFECT ON
TEMPERATURES. MODELS REMAIN IN GOOD AGREEMENT SHOWING THE ABOVE
MENTIONED UPPER LEVEL DISTURBANCE OVER SC CANADA CONTINUING TO
SLIDE SOUTHEAST THROUGH THE DAY TODAY...WITH THE TIMING OF THE
ACCOMPANYING SFC COLD FRONT/NORTHWESTERLY WINDS STILL EXPECTED TO
PASS THROUGH THE CWA DURING THE AFTERNOON HOURS. THE TIMING MAKES
TEMPERATURES TODAY PRETTY DIFFICULT...ESP WITH MODELS/GUIDANCE NOT
IN VERY GOOD AGREEMENT...MAINLY FOR THOSE NORTHWESTERN PORTIONS OF
THE CWA...WHICH WILL PROB SEE THEIR HIGHS CLOSER TO MIDDAY/EARLY
AFTN VS MID AFTN FURTHER SOUTH. OVERALL DIDNT MAKE MANY CHANGES TO
THE INHERITED FORECAST...WHICH CONTINUES TO CALL FOR GENERALLY MID
30S ACROSS SC NEB...WITH LOWER 40S IN NC KS. CERTAINLY SOMETHING
FOR THE DAYSHIFT TO KEEP AN EYE ON.
AS FAR AS THE POSSIBILITY OF FLURRIES GOES...DECIDED TO KEEP THE
MENTION OUT OF THE FORECAST. AS THAT DISTURBANCE SWINGS SOUTH...IT
WILL BRING ALONG MORE CLOUD COVER AND COLDER TEMPERATURES...AND
WHILE MODELS DO SHOW SOME BATCHES OF INCREASED LOWER LEVEL /BELOW
700MB/ MOISTURE MOVING INTO THE REGION...MAINLY THIS
AFTERNOON...THERE IS ALSO PRETTY GOOD AGREEMENT WITH KEEPING THE
BETTER RH AND COLDER TEMPS MORE FAVORABLE FOR FLURRIES
NORTH/NORTHEAST OF THE CWA...BARELY. THE OPER NAM/GFS/EC CONTINUE
TO SHOW THE CWA DRY...AS DOES THE HRRR. THE RAP AND ONE RUN OF THE
4 KM SHOW PERHAPS THE FAR N/NE EDGE OF THE CWA MAYBE SEEING A
FEW...BUT AM GOING TO CONTINUE TO EXCLUDE THE MENTION.
REALLY THE BRUNT OF THE COLDER AIR HOLDS OFF FROM MOVING INTO THE
CWA UNTIL LATER TODAY AND MAINLY THIS EVENING/TONIGHT. AS HAS BEEN
THE CASE OVER THE PAST FEW DAYS...MODELS CONTINUE TO SHOW THE
MAIN AXIS OF THE TROUGH...AND THUS THE COLDEST AIR...SETTING UP
JUST EAST OF THE CWA TONIGHT/THROUGH MONDAY. WHILE THE CWA MAY
CATCH A BRIEF BREAK FROM CLOUD COVER TONIGHT...EXPECTING TO SEE
ADDITIONAL CLOUD COVER /MAINLY UPPER LEVEL/ STREAMING IN FROM THE
NORTHWEST...KEEPING MAINLY THE NORTHEASTERN HALF OF THE CWA UNDER
PARTLY/MOSTLY CLOUDY SKIES ON MONDAY. DIDNT MAKE ANY NOTABLE
CHANGES TO MONDAYS HIGHS...WHICH RANGE FROM THE LOWER 20S IN THE
NORTHEAST TO LOWER 30S IN THE SOUTHWEST. SURFACE HIGH PRESSURE
SLIDING IN FROM THE NORTHWEST WILL BRING FAIRLY LIGHT WINDS FOR
MOST LOCATIONS.
MONDAY NIGHT THROUGH TUESDAY...THE MAIN UPPER LEVEL TROUGH/COLDEST
AIR ALREADY STARTS ITS EASTWARD SHIFT MONDAY NIGHT...WHICH WILL
BRING A REBOUND IN TEMPS FOR TUESDAY. THE POSSIBILITY OF GETTING
CLIPPED IN THE NORTH BY MORE FLURRIES OR LIGHT SNOW WILL BE
SOMETHING TO CONSIDER WITH UPCOMING MODEL RUNS. CURRENTLY AM
KEEPING THE MENTION OUT OF THE FORECAST...WITH MODELS SHOWING THE
COLDER TEMPS AND BETTER POTENTIAL /MAINLY MONDAY NIGHT INTO THE
FIRST HALF OF TUESDAY/...DRIVEN BY A STRONG UPPER LEVEL JET
STREAK NOSING IN FROM THE N/NW...REMAINING ONCE AGAIN JUST OUTSIDE
THE N/NE EDGE OF THE CWA. WITH THE WARMER AIR STARTING TO BUILD
BACK IN FROM THE WEST...HIGHS CURRENTLY RANGE FROM THE UPPER 20S
IN THE NORTHEAST TO LOWER 40S IN THE WEST...AND SOME MODELS
SUGGEST THE WEST SHOULD BE WARMER. OVERNIGHT LOWS EXPECTED TO
REBOUND FROM THE SINGLE DIGITS/TEENS MONDAY NIGHT TO THE
TEENS/NEAR 20 TUESDAY NIGHT.
.LONG TERM...(WEDNESDAY THRU SATURDAY)
THE MAIN STORY: BONE DRY PATTERN CONTINUES WITH RE-AMPLIFYING NW
FLOW STUNTING TEMP RECOVERY...BUT SIGNALS CONTINUE FOR SOME PRECIP
POTENTIAL VERY LATE THIS MONTH.
PATTERN: THE HIGHLY AMPLIFIED WRN N AMERICA RIDGE/ERN TROF WILL
MEET ITS DEMISE NEXT WEEK AS A PACIFIC SHRTWV TROF MOVES ONSHORE
IN THE PAC NW WED AND MOVES THRU THE RIDGE. AS THIS TROF MOVES
INTO THE LGWV TROF THU-FRI...THE PATTERN WILL RE-AMPLIFY
SOMEWHAT...CURBING OUR WARM-UP FRI-SAT. RIDGING THEN ADVANCES OVER
THE PLAINS NEXT WEEKEND...FOLLOWED BY LOWERING HGTS OVER WRN N
AMERICA THE LAST WEEK OF JAN...SUGGESTING A PERIOD OF STORMINESS
AND PCPN POTENTIAL.
MODELS: THERE IS GOOD AGREEMENT AMONGST THE 00Z EC/GFS/GEM ON THIS
SCENARIO THRU 00Z/SAT. THE ONE CAVEAT...THE OPERATIONAL 18Z/00Z GFS
ARE NOT AS AMPLIFIED WITH THE TEMPORARILY REINVIGORATED RIDING OVER
WRN N AMERICA. IN FACT...THE GFS ENSEMBLE MEAN IS CLOSER TO THE
MORE AMPLIFIED 12Z/00Z EC CYCLES. THIS FCST INCORPORATES
EC/GFS/GEM/HPC GUIDANCE THRU 00Z/SAT. BEYOND THAT ITS HPC/EC AND
EC/GFS ENSEMBLE MEANS.
TEMPS: ESSENTIALLY NEAR NORMAL THRU SAT WITH ONE DAY OF BELOW
NORMAL FRI.
HAZARDS: NONE ENVISIONED ATTM.
UPCOMING PCPN OPPORTUNITIES: NOTHING NOTABLE THRU AT LEAST SAT AND
PROBABLY TO MON 1/28. HOWEVER...ODDS ARE INCREASING FOR A MDT
PCPN EVENT AS WE CLOSE THE BOOKS ON JAN.
THE DAILY DETAILS...
WED: M/SUNNY. PROBABLY NEAR NORMAL TEMPS. LEE TROF INTENSIFIES
WITH TROF MOVING INTO PAC NW...AIDING IN MODEST TEMP RECOVERY.
TEMP CONFIDENCE GRAPHICS SHOW ABOVE NORMAL SPREAD IN TEMPS.
THU: P/CLOUDY. A DRY COLD FRONTAL PASSAGE IN THE PRE-DAWN HRS. LOW
PRES EJECTS OUT OF CO ACROSS KS/OK. SOME DIFF/S IN TIMING REMAIN
WITH THE EC/GEM FASTER AND MORE POTENT THAN THE GFS. THE 00Z EC
ENSEMBLES HAVE COME INTO MUCH BETTER AGREEMENT ON SLP SINCE ITS
12Z RUN. HPC IS IN AGREEMENT SO WE/LL ROLL WITH THIS SCENARIO.
ABOVE NORMAL UNCERTAINTY IN TEMPS.
THU HAS POTENTIAL TO BE A BREEZY DAY. HOWEVER...SOME BAGGINESS IN
THE PRES TROF OF A REINFORCING SHOT OF COLD AIR COULD MITIGATE.
THU NGT: ANOTHER PUSH OF COLDER AIR MOVES THRU AS THE SHRTWV TROF
PASSES...BUT THE WORST OF IT REMAINS OFF TO THE N AND E.
FRI: P/CLOUDY. ARCTIC HIGH PRES EXPANDS OVER THE MS VALLEY. IF THE
EC IS RIGHT ANOTHER WEAK LOW MOVES THRU DELIVERING ANOTHER PUSH OF
MARGINALLY COLD AIR. CONFIDENCE IS ABOVE NORMAL ON A COOL DOWN.
TEMPS PROBABLY CLOSE TO 10F BELOW NORMAL.
SAT: SUNNY AS YET ANOTHER ARCTIC HIGH EXPANDS OVER THE MS VALLEY.
HGTS BEGIN RISING AS BROAD RIDGING ADVANCES TOWARD THE PLAINS. WAA
BEGINS WITH A NEW LEE TROF DEVELOPING.
BEYOND SAT...
A VERY NICE WARM-UP COMMENCES SUN THAT COULD LINGER INTO EARLY THE
FOLLOWING WEEK 1/28-29 DEPENDENT ON HOW THE PATTERN SHAPES UP.
WE COULD SEE 1 OR 2 DAYS OF MUCH ABOVE NORMAL TEMPS (+10F OR
MORE). IF WE ROLL WITH THE OPERATIONAL EC AND THE EC/GFS ENSEMBLES
LATE THIS WEEK...THEN WE MUST GO SLOWER THAN THE OPERATIONAL GFS
FOR EARLY THE FOLLOWING WEEK. THE GREATER AMPLIFIED SCENARIO WILL
SLOW THINGS DOWN UPSTREAM. EITHER WAY...THE NEXT PAC TROF WILL DIG
INTO THE DESERT SW THE LAST WEEK OF JAN. THIS IS A FAVORABLE SETUP
FOR A DECENT PCPN EVENT HERE AND WITH THE LOW TRACKING S OF THE
FCST AREA...THIS COULD END UP BEING THE WINTRY VARIETY. HOPEFULLY
WE/LL HAVE TIME TO ENTRAIN GOOD MSTR AFTER MULTIPLE EPISODES OF
CONTINENTAL POLAR AIR HAVE PLUNGED INTO THE GULF.
&&
.AVIATION...(06Z GRI TAF THROUGH 06Z SUNDAY NIGHT)
REST OF TNGT: VFR WITH MULTIPLE LAYERS OF MID-HIGH CIGS ABOVE 15K
FT. N WINDS WILL AVERAGE AROUND 10 KTS UNTIL 09Z WHEN WINDS WILL
GRADUALLY VEER TO E AND DECREASE TO 4 KTS OR LESS.
SUN: VFR WITH MULTIPLE MID-HIGH CIGS ABOVE 15K FT. LIGHT WINDS
WILL CONTINUE TO VEER TO SE-S-SW AT 5 KTS OR LESS...AS AN ARCTIC
COLD FRONT APPROACHES AND WEAK LOW PRES MOVES ALONG THE FRONT.
FROPA CURRENTLY EXPECTED 19-21Z. AFTER FROPA...EXPECT A WSHFT TO
N WITH GUSTS UP TO 22 KTS. SHOULD SEE LOW-END VFR OVC035 MOVE IN.
THERE IS A LOW PROB FOR MVFR CIGS.
SUN THRU 06Z: PROBABLY VFR. N-NNW WINDS DIMINISH AROUND 03Z WITH
BKN 3500 FT CIGS CONTINUING. THERE IS A LOW PROB FOR MVFR CIGS.
CIG CONFIDENCE: HIGH THRU 19Z. THEN AVERAGE THEREAFTER.
VSBY CONFIDENCE: HIGH
WIND CONFIDENCE: AVERAGE. EXACT TIME OF FROPA UNCERTAIN. ALSO
UNSURE OF DEGREE OF GUSTINESS POST-FROPA.
WX CONFIDENCE: HIGH
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
KS...NONE.
&&
$$
SHORT...ADO
LONG/AVIATION...HALBLAUB
AREA FORECAST DISCUSSION
NWS CARIBOU ME
505 PM EST SUN JAN 20 2013
.SYNOPSIS...
AN ARCTIC COLD FRONT TO CROSS THE REGION THIS EVENING. LOW PRESSURE
PASSES SOUTH OF THE AREA TUESDAY WITH A COLD AIR MASS TO REMAIN
ACROSS THE AREA ALL WEEK.&&
.NEAR TERM /THROUGH MONDAY/...
UPDATE 1700L: PRIMARY ARCTIC BNDRY EXITING THE FA ATTM W/ SECONDARY
BNDRY ENTERING FAR NWRN AREAS. THIS SECONDARY BNSRY IS EXPECTED TO
SWEEP SEWRD ACROSS THE FA DURING THE EVE HRS AND WILL BE
ACCOMPANIED BY SOME SNOW SHOWERS SPCLY NRN AREAS. THIS FRONT WILL
BE FOLLOWED BY STRONG GUSTY NW WNDS AND STRONG CAA ALLOWING TEMPS
TO FALL RAPIDLY LATER THIS EVE AND THRU THE OVERNGT HRS. HAVE
ADJUSTED POPS TO BETTER FIT CURRENT AND EXPECTED TRENDS W/ ALL WND
CHILL WRNGS/ADVS AND THE WND ADV CONTG...
INTENSE AREA OF LOW PRESSURE CURRENTLY MOVING TO THE NORTH OF THE
STATE. LINE OF SNOW SHOWERS CURRENTLY MOVING THROUGH. SECONDARY
COLD FRONT STILL TO THE WEST OF NEW ENGLAND AND SHOULD MOVE ACROSS
THE STATE IN THE EARLY EVENING. EXPECT GUSTY CONDITIONS TO DEVELOP
AS COLD AIR MOVES IN. WILL KEEP WIND ADVISORY IN PLACE. HAVE
ADJUSTED WIND GUSTS A LITTLE LOWER FOR LATE AFTERNOON. FOR POP AND
WEATHER GRIDS HAVE INITIALIZED POPS WITH RUC13 THEN MANUALLY
ADJUSTED INCREASE POPS A LITTLE FURTHER TO SOUTH. LATER TONIGHT
EXPECT RAPID TEMPERATURE DROP ACCOMPANIED BY STRONG WINDS AND
GUSTY CONDITIONS SO WILL ALSO KEEP WIND CHILL ADVISORY FOR NORTH
AND WIND CHILL WATCH IN FAR NORTHWEST.
&&
.SHORT TERM /MONDAY NIGHT THROUGH WEDNESDAY/...
THE MAIN STORY FOR THIS PORTION OF THE FORECAST WILL BE BITTERLY
COLD TEMPERATURES. COMBINED WITH WITH THE BREEZY CONDITIONS WHICH
WILL CONTINUE MONDAY THIS WILL CREATE VERY LOW WIND CHILLS,
ESPECIALLY NORTH, WHERE VALUES WILL BE IN THE MINUS 20S AND MINUS
30S. HIGHS MONDAY IN THE NORTH WILL RANGE FROM 5 BELOW TO 5 ABOVE
ZERO WITH SOUTHERN AREAS SEEING HIGHS IN THE TEENS.
WINDS WILL ABATE FOR MONDAY NIGHT WITH TEMPERATURES DIPPING TO NEAR
OR BELOW MINUS 20 NORTH. ACROSS THE SOUTH, CLOUDS WILL INCREASE AS
A LOW PRESSURE SYSTEM DEVELOPS OFF THE MID ATLANTIC COAST AND
MOVES NORTH AND EAST. THE NORTHERN EDGE OF THE PRECIPITATION SHIELD
LOOKS TO SET UP VERY CLOSE TO COASTAL AREAS OF THE CWA WITH THE
NEW GFS TAKING THE SYSTEM SLIGHTLY FARTHER NORTH. IF THIS SOLUTION
WERE TO VERIFY IT COULD RESULT IN A COUPLE INCHES OF SNOW RIGHT
ALONG THE COAST. HOWEVER THE CANADIAN AND THE ECMWF REMAIN A BIT
FARTHER SOUTH SO AT THIS POINT OPTED TO MAINTAIN CONTINUITY WITH
PREVIOUS FORECAST KEEPING JUST CHANCE POPS IN ALONG THE COAST FOR
LATE MONDAY NIGHT INTO TUESDAY. OTHERWISE TUESDAY WILL FEATURE
MAINLY CLOUDY SKIES WITH VERY COLD TEMPERATURES. HIGHS LOOK TO BE
A COUPLE DEGREES COLDER THAN MONDAY`S VALUES MEANING MANY AREAS IN
THE NORTH WILL STAY AT OR BELOW ZERO.
AS THE AFOREMENTIONED LOW MOVES OFF TO THE NORTHEAST HEADING INTO TUESDAY
NIGHT AND WEDNESDAY THIS WILL DRAG THE CORE OF THE COLDEST AIR
DOWN OVER THE CWA. IN ADDITION, WINDS WILL PICK UP AGAIN WEDNESDAY
DUE TO THE GRADIENT BETWEEN THE DEPARTING LOW TO THE EAST AND HIGH
PRESSURE TO THE WEST. THIS WILL ONCE AGAIN RESULT IN BITTER WIND
CHILLS LIKELY REACHING AT LEAST ADVISORY LEVELS IN THE NORTH.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/...
IT LOOKS LIKE WE WILL GET A REPRIEVE FROM THIS LATEST ARCTIC
BLAST COME LATE WEEK AND THEN A RETURN TO ANOTHER POTENTIAL SHOT
OF ARCTIC AIR BY THE WEEKEND.
AN UPPER LEVEL IS FORECAST TO SWING ACROSS THE REGION BY WEDNESDAY
EVENING W/ANOTHER SHOT OF VERY COLD ARCTIC AIR TO INVADE THE
REGION. CLOUDS AND SCATTERED SNOW SHOWERS/FLURRIES WILL END BY
LATE EVENING W/SKIES CLEARING LATE IN THE NIGHT. THIS WILL SET THE
STAGE FOR ANOTHER VERY COLD NIGHT W/WINDS GRADUALLY DROP OFF AS
SFC HIGH PRES MOVES E FROM CANADA. WE COULD BE SEEING WIND CHILLS
HEADLINES AGAIN IN THURSDAY MORNING. A CAVEAT TO THIS IS THE ECMWF
AND THE CANADIAN GLOBAL AS THEY BOTH KEEP THE CENTER OF THE SFC
HIGH WELL W OF THE STATE BACK IN OTTAWA W/A WNW WIND CONTINUING.
THIS WOULD MEAN OVERNIGHT TEMPERATURES WEDNESDAY NIGHT WOULD BE A
BIT WARMER ALTHOUGH WELL BELOW NORMAL AND DAYTIME HIGH TEMPERATURES
FOR THURSDAY WILL BE COLDER AS WELL. ATTM, DECIDED TO BLEND THE
GMOS AND ECMWF FOR MINS WEDNESDAY NIGHT AND FOR MAXES ON THURSDAY
TAKING THIS INTO ACCOUNT.
THINGS LOOK TO BE INTERESTING COME FRIDAY INTO SATURDAY AS THE
LAST 2 RUNS OF THE ECMWF SHOW A LOW PRES SYSTEM COMING OUT OF THE
OHIO VALLEY AND MOVING ACROSS THE GULF OF MAINE. THE CANADIAN
GLOBAL INDICATES THE SAME IDEA AND BRING SIGNIFICANT SNOWFALL TO
EASTERN AND DOWNEAST MAINE AND POSSIBLY NORTHERN AREAS. THE GFS IS
WEAKER AND FASTER W/THE SFC LOW AND KEEPS THE LOW FURTHER S. SOME
OF THE INDIVIDUAL MEMBERS OF THE GFS DO SUPPORT THE ECMWF AND
CANADIAN GLOBAL SETUP. THEREFORE, A BLEND OF THE GMOS AND ECMWF
WAS USED FOR THIS TIME FRAME WHICH MEANS AN INCREASE IN POPS TO 40%
AND WENT W/SNOW INSTEAD OF SNOW SHOWERS. DECIDED TO BRING
TEMPERATURES UP AS WELL FOR FRIDAY INTO SATURDAY W/LOWER TEENS
ACROSS THE NORTH AND MID TEENS TO AROUND 20 CENTRAL AND DOWNEAST.
IT WILL INTERESTING TO SEE HOW THE LATER RUNS TREAT THIS POTENTIAL
SYSTEM.
&&
.AVIATION /22Z SUNDAY THROUGH FRIDAY/...
NEAR TERM: IFR CONDITIONS EARLY IN SNOW SQUALLS THEN VFR
CONDITIONS LATER TONIGHT INTO MONDAY.
SHORT TERM: VFR EXPECTED MONDAY INTO TUESDAY WITH THE EXCEPTION
OF KBHB AND POSSIBLY KBGR TUE AS -SN MAY PRODUCE A PERIOD OF
MVFR/IFR. A FEW PATCHES OF HIGHER END MVFR MAY BE FLOATING AROUND
IN THE COLD AIR IN THE NORTH WED-THU...BUT VFR SHOULD BY FAR BE
THE PREVAILING CONDITION.
&&
.MARINE...
NEAR TERM: EXPECT WINDS TO GRADUALLY BECOME OFF-SHORE LATER
TONIGHT. GRADIENT SLACKENS OFF BEFORE EXTREMELY COLD AIR GETS OVER
COASTAL WATERS SO NOT ENOUGH MIXING TO GET STORM WINDS TO SURFACE.
FOR WAVES: SOUTHWEST FETCH WILL END AS WINDS BECOME OFFSHORE. WAVE
HEIGHTS COULD TOP OFF AROUND 15 FEET BEFORE FETCH ENDS.
SHORT TERM: A SMALL CRAFT ADVISORY WILL LIKELY NEED TO CONTINUE
INTO AT LEAST MONDAY MORNING BEFORE THE WIND DIMINISHES BELOW
ADVISORY LEVELS BY AFTERNOON. ANOTHER PERIOD OF SCA LEVEL WINDS
POSSIBLE BY LATE MONDAY NIGHT AS LOW PRESSURE PASSES SOUTH OF THE
WATERS. THERE WILL PROBABLY BE ENOUGH OF A PRESSURE GRADIENT IN
THE WAKE OF THE LOW AS HIGH PRESSURE BEGINS TO BUILD TOWARD THE
WATERS FOR BORDERLINE SCA WIND RIGHT THROUGH THURSDAY.
&&
.CAR WATCHES/WARNINGS/ADVISORIES...
ME...WIND ADVISORY UNTIL 10 PM EST THIS EVENING FOR MEZ001>006-010-
011-015>017-029>032.
WIND CHILL ADVISORY FROM 1 AM TO 1 PM EST MONDAY FOR MEZ002-
004>006-010.
WIND CHILL WARNING FROM 1 AM TO 1 PM EST MONDAY FOR MEZ001-003.
MARINE...GALE WARNING UNTIL 7 AM EST MONDAY FOR ANZ050>052.
&&
$$
NEAR TERM...MIGNONE/KHW
SHORT TERM...FITZSIMMONS
LONG TERM...HEWITT
AVIATION...MIGNONE
MARINE...MIGNONE/KHW/FITZSIMMONS
AREA FORECAST DISCUSSION
NWS CARIBOU ME
343 PM EST SUN JAN 20 2013
.SYNOPSIS...
AN ARCTIC COLD FRONT TO CROSS THE REGION THIS EVENING. LOW PRESSURE
PASSES SOUTH OF THE AREA TUESDAY WITH A COLD AIR MASS TO REMAIN
ACROSS THE AREA ALL WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
INTENSE AREA OF LOW PRESSURE CURRENTLY MOVING TO THE NORTH OF THE
STATE. LINE OF SNOW SHOWERS CURRENTLY MOVING THROUGH. SECONDARY
COLD FRONT STILL TO THE WEST OF NEW ENGLAND AND SHOULD MOV ACROSS
THE STATE IN THE EARLY EVENING. EXPECT GUSTY CONDITIONS TO DEVELOP
AS COLD AIR MOVES IN. WILL KEEP WIND ADVISORY IN PLACE. HAVE
ADJUSTED WIND GUSTS A LITTLE LOWER FOR LATE AFTERNOON. FOR POP AND
WEATHER GRIDS HAVE INITIALIZED POPS WITH RUC13 THEN MANUALLY
ADJUSTED INCREASE POPS A LITTLE FURTHER TO SOUTH. LATER TONIGHT
EXPECT RAPID TEMPERATURE DROP ACCOMPANIED BY STRONG WINDS AND
GUSTY CONDITIONS SO WILL ALSO KEEP WIND CHILL ADVISORY FOR NORTH
AND WIND CHILL WATCH IN FAR NORTHWEST.
&&
.SHORT TERM /MONDAY THROUGH WEDNESDAY/...
THE MAIN STORY FOR THIS PORTION OF THE FORECAST WILL BE BITTERLY
COLD TEMPERATURES. COMBINED WITH WITH THE BREEZY CONDITIONS WHICH
WILL CONTINUE MONDAY THIS WILL CREATE VERY LOW WIND CHILLS,
ESPECIALLY NORTH, WHERE VALUES WILL BE IN THE MINUS 20S AND MINUS
30S. HIGHS MONDAY IN THE NORTH WILL RANGE FROM 5 BELOW TO 5 ABOVE
ZERO WITH SOUTHERN AREAS SEEING HIGHS IN THE TEENS.
WINDS WILL ABATE FOR MONDAY NIGHT WITH TEMPERATURES DIPPING TO NEAR
OR BELOW MINUS 20 NORTH. ACROSS THE SOUTH, CLOUDS WILL INCREASE AS
A LOW PRESSURE SYSTEM DEVELOPS OFF THE MID ATLANTIC COAST AND
MOVES NORTH AND EAST. THE NORTHERN EDGE OF THE PRECIPITATION SHIELD
LOOKS TO SET UP VERY CLOSE TO COASTAL AREAS OF THE CWA WITH THE
NEW GFS TAKING THE SYSTEM SLIGHTLY FARTHER NORTH. IF THIS SOLUTION
WERE TO VERIFY IT COULD RESULT IN A COUPLE INCHES OF SNOW RIGHT
ALONG THE COAST. HOWEVER THE CANADIAN AND THE ECMWF REMAIN A BIT
FARTHER SOUTH SO AT THIS POINT OPTED TO MAINTAIN CONTINUITY WITH
PREVIOUS FORECAST KEEPING JUST CHANCE POPS IN ALONG THE COAST FOR
LATE MONDAY NIGHT INTO TUESDAY. OTHERWISE TUESDAY WILL FEATURE
MAINLY CLOUDY SKIES WITH VERY COLD TEMPERATURES. HIGHS LOOK TO BE
A COUPLE DEGREES COLDER THAN MONDAY`S VALUES MEANING MANY AREAS IN
THE NORTH WILL STAY AT OR BELOW ZERO.
AS THE AFOREMENTIONED LOW MOVES OFF TO THE NORTHEAST HEADING INTO TUESDAY
NIGHT AND WEDNESDAY THIS WILL DRAG THE CORE OF THE COLDEST AIR
DOWN OVER THE CWA. IN ADDITION, WINDS WILL PICK UP AGAIN WEDNESDAY
DUE TO THE GRADIENT BETWEEN THE DEPARTING LOW TO THE EAST AND HIGH
PRESSURE TO THE WEST. THIS WILL ONCE AGAIN RESULT IN BITTER WIND
CHILLS LIKELY REACHING AT LEAST ADVISORY LEVELS IN THE NORTH.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/...
IT LOOKS LIKE WE WILL GET A REPRIEVE FROM THIS LATEST ARCTIC
BLAST COME LATE WEEK AND THEN A RETURN TO ANOTHER POTENTIAL SHOT
OF ARCTIC AIR BY THE WEEKEND.
AN UPPER LEVEL IS FORECAST TO SWING ACROSS THE REGION BY WEDNESDAY
EVENING W/ANOTHER SHOT OF VERY COLD ARCTIC AIR TO INVADE THE
REGION. CLOUDS AND SCATTERED SNOW SHOWERS/FLURRIES WILL END BY
LATE EVENING W/SKIES CLEARING LATE IN THE NIGHT. THIS WILL SET THE
STAGE FOR ANOTHER VERY COLD NIGHT W/WINDS GRADUALLY DROP OFF AS
SFC HIGH PRES MOVES E FROM CANADA. WE COULD BE SEEING WIND CHILLS
HEADLINES AGAIN IN THURSDAY MORNING. A CAVEAT TO THIS IS THE ECMWF
AND THE CANADIAN GLOBAL AS THEY BOTH KEEP THE CENTER OF THE SFC
HIGH WELL W OF THE STATE BACK IN OTTAWA W/A WNW WIND CONTINUING.
THIS WOULD MEAN OVERNIGHT TEMPERATURES WEDNESDAY NIGHT WOULD BE A
BIT WARMER ALTHOUGH WELL BELOW NORMAL AND DAYTIME HIGH TEMPERATURES
FOR THURSDAY WILL BE COLDER AS WELL. ATTM, DECIDED TO BLEND THE
GMOS AND ECMWF FOR MINS WEDNESDAY NIGHT AND FOR MAXES ON THURSDAY
TAKING THIS INTO ACCOUNT.
THINGS LOOK TO BE INTERESTING COME FRIDAY INTO SATURDAY AS THE
LAST 2 RUNS OF THE ECMWF SHOW A LOW PRES SYSTEM COMING OUT OF THE
OHIO VALLEY AND MOVING ACROSS THE GULF OF MAINE. THE CANADIAN
GLOBAL INDICATES THE SAME IDEA AND BRING SIGNIFICANT SNOWFALL TO
EASTERN AND DOWNEAST MAINE AND POSSIBLY NORTHERN AREAS. THE GFS IS
WEAKER AND FASTER W/THE SFC LOW AND KEEPS THE LOW FURTHER S. SOME
OF THE INDIVIDUAL MEMBERS OF THE GFS DO SUPPORT THE ECMWF AND
CANADIAN GLOBAL SETUP. THEREFORE, A BLEND OF THE GMOS AND ECMWF
WAS USED FOR THIS TIMEFRAME WHICH MEANS AN INCREASE IN POPS TO 40%
AND WENT W/SNOW INSTEAD OF SNOW SHOWERS. DECIDED TO BRING
TEMPERATURES UP AS WELL FOR FRIDAY INTO SATURDAY W/LOWER TEENS
ACROSS THE NORTH AND MID TEENS TO AROUND 20 CENTRAL AND DOWNEAST.
IT WILL INTERESTING TO SEE HOW THE LATER RUNS TREAT THIS POTENTIAL
SYSTEM.
&&
.AVIATION /20Z SUNDAY THROUGH FRIDAY/...
NEAR TERM: IFR CONDITIONS EARLY IN SNOW SQUALLS THEN VFR
CONDITIONS LATER TONIGHT INTO MONDAY.
SHORT TERM: VFR EXPECTED MONDAY INTO TUESDAY WITH THE EXCEPTION
OF KBHB AND POSSIBLY KBGR TUE AS -SN MAY PRODUCE A PERIOD OF
MVFR/IFR. A FEW PATCHES OF HIGHER END MVFR MAY BE FLOATING AROUND
IN THE COLD AIR IN THE NORTH WED-THU...BUT VFR SHOULD BY FAR BE
THE PREVAILING CONDITION.
&&
.MARINE...
NEAR TERM: EXPECT WINDS TO GRADUALLY BECOME OFF-SHORE LATER
TONIGHT. GRADIENT SLACKENS OFF BEFORE EXTREMELY COLD AIR GETS OVER
COASTAL WATERS SO NOT ENOUGH MIXING TO GET STORM WINDS TO SURFACE.
FOR WAVES: SOUTHWEST FETCH WILL END AS WINDS BECOME OFFSHORE. WAVE
HEIGHTS COULD TOP OFF AROUND 15 FEET BEFORE FETCH ENDS.
SHORT TERM: A SMALL CRAFT ADVISORY WILL LIKELY NEED TO CONTINUE
INTO AT LEAST MONDAY MORNING BEFORE THE WIND DIMINISHES BELOW
ADVISORY LEVELS BY AFTERNOON. ANOTHER PERIOD OF SCA LEVEL WINDS
POSSIBLE BY LATE MONDAY NIGHT AS LOW PRESSURE PASSES SOUTH OF THE
WATERS. THERE WILL PROBABLY BE ENOUGH OF A PRESSURE GRADIENT IN
THE WAKE OF THE LOW AS HIGH PRESSURE BEGINS TO BUILD TOWARD THE
WATERS FOR BORDERLINE SCA WIND RIGHT THROUGH THURSDAY.
&&
.CAR WATCHES/WARNINGS/ADVISORIES...
ME...WIND ADVISORY UNTIL 10 PM EST THIS EVENING FOR MEZ001>006-010-
011-015>017-029>032.
WIND CHILL ADVISORY FROM 1 AM TO 1 PM EST MONDAY FOR MEZ002-
004>006-010.
WIND CHILL WARNING FROM 1 AM TO 1 PM EST MONDAY FOR MEZ001-003.
MARINE...GALE WARNING UNTIL 7 AM EST MONDAY FOR ANZ050>052.
&&
$$
NEAR TERM...MIGNONE
SHORT TERM...FITZSIMMONS
LONG TERM...HEWITT
AVIATION...MIGNONE
MARINE...MIGNONE/FITZSIMMONS
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
500 PM EST SUN JAN 20 2013
.SHORT TERM...(THIS EVENING THROUGH MONDAY)
ISSUED AT 455 PM EST SUN JAN 20 2013
WATER VAPOR IMAGERY AND RUC ANALYSIS SHOW A HIGH AMPLITUDE PATTERN
OVER NAMERICA WITH A RIDGE ALONG THE W COAST THRU AK AND A DEEP TROF
COVERING MUCH OF CNTRL/ERN CANADA INTO THE NCNTRL CONUS/GREAT LAKES.
BEHIND LAST NIGHTS SHORTWAVE PASSAGE...INCREASINGLY COLDER ARCTIC
AIR IS FLOWING INTO THE AREA. LATEST RUC ANALYSIS SHOWS 850MB TEMPS
OF -22 TO -24C OVER UPPER MI/LAKE SUPERIOR. UPSTREAM 850MB TEMPS ON
12Z ROABS WERE -25C/-26C/-27C AT KINL/CWPL/CYQD RESPECTIVELY.
FARTHER UPSTREAM...POOL OF SUB -30C AIR AT 850MB IS JUST NW OF CYQD
AS 00Z RAOB AT CYSM SHOWED -34C AT 850MB. THAT CORE OF ARCTIC AIR
WILL BE SETTLING INTO THE UPPER LAKES MON/MON NIGHT BEHIND SHORTWAVE
CURRENTLY DROPPING SSE THRU MANITOBA. ANOTHER WEAKER SHORTWAVE IS
PASSING THRU THE UPPER GREAT LAKES ATTM. HOWEVER...WAVE HAS HAD NO
DISCERNIBLE INFLUENCE ON LES PER RADAR IMAGERY. MOST INTENSE LES
BAND IS STREAMING INTO WRN ALGER COUNTY AS LAND BREEZE COMPONENT
STRENGTHENS CONVERGENCE OFF MARQUETTE COUNTY. TO THE W...WIND
PARALLEL LES BANDS ARE STREAMING INTO WRN UPPER MI. WEBCAMS SHOW
HIGHLY VARIABLE VIS AS -SHSN PASS. SINCE ARCTIC AIR HAS PUSHED DGZ
TO NEAR THE SFC...SNOWFLAKE SIZE IS SMALL...MAKING THE -SHSN VERY
EFFECTIVE AT REDUCING VIS. THIS IS ALSO KEEPING NEW SNOW
ACCUMULTIONS ON THE LIGHT SIDE OVER THE W.
AFOREMENTIONED SHORTWAVE IN MANITOBA WILL DROP ACROSS THE UPPER
LAKES OVERNIGHT TONIGHT THRU MON MORNING. FORCING ASSOCIATED WITH
WAVE PER DEEP LAYER QVECTOR CONVERGENCE WILL GIVE A BOOST TO LES
TONIGHT THRU MID MORNING MON AS MOISTURE DEPTH INCREASES AND
INVERSION RISES TO AROUND 10KFT. NORMALLY WITH SUCH SYNOPTIC
ENHANCEMENT...WOULD BE CONCERNED ABOUT A SIGNIFICANT INCREASE IN HVY
LES/SNOW ACCUMULATIONS. HOWEVER...WITH INCREASINGLY COLDER AIR
CONTINUING TO PUSH DGZ TOWARD THE SFC OR MORE LIKELY ELIMINATING IT
ALTOGETHER...SNOW ACCUMULATIONS WILL BE LIMITED BY SMALL SNOWFLAKE
SIZE. ONLY AREAS LIKELY TO SEE MORE SIGNIFICANT SNOW ACCUMULATIONS
WILL BE THOSE THAT ARE IMPACTED BY LES WITHIN STRONGER CONVERGENCE
ZONES AS THE CONVERGENCE WILL PROVIDE AN OPPORTUNITY FOR MORE
SIGNIFICANT LAKE MODERATION AND THUS POSSIBLY RAISE DGZ INTO A
PORTION OF THE CONVECTIVE LAYER. THOSE ENHANCED CONVERGENCE ZONES
WILL BE DIFFICULT TO PIN DOWN EXACTLY...BUT THERE SHOULD BE 2 OR 3.
ONE SHOULD OCCUR IN ONTONAGON COUNTY...PROBABLY AROUND THE VCNTY OF
THE PORCUPINE MTNS DUE TO STRENGTHENING LAND BREEZE OFF NW WI. THE
OTHERS SHOULD BE IN ERN ALGER COUNTY AND A PORTION OF LUCE COUNTY
DUE TO STRENGTHENING LAND BREEZES OFF MARQUETTE/WRN ALGER COUNTY AND
ALSO OFF ONTARIO. ALL HIGH RES MODEL GUIDANCE POINT TOWARD THE
PROGRESSING LAND BREEZES OVER SCNTRL/ERN LAKE SUPERIOR LEADING TO
EITHER MESO LOW DEVELOPMENT OR SHARP SFC TROFFING SOMEWHERE IN THE
AREA BTWN GRAND MARAIS/CARIBOU ISLAND AND WHITEFISH PT. IF A MESO
LOW DEVELOPS FAR ENOUGH OFFSHORE...IT`S POSSIBLE MOST OF THE LES
WILL ALSO SHIFT OFFSHORE. IF A SHARP CONVERGENCE ZONE DEVELOPS...
MDT/HVY LES COULD STREAM ONSHORE INTO A SMALL PART OF ERN ALGER/NW
LUCE FOR SEVERAL HRS. WITH PASSAGE OF SHORTWAVE...AT SOME POINT MON
MORNING/EARLY AFTN...THE SHARP SFC TROF/MESO LOW WILL BE PUSHED
ONSHORE. GIVEN THE UNCERTAINTY ON THE MESOSCALE DETAILS...WILL
CONTINUE TO HIGHLIGHT ERN ALGER/NRN LUCE CLOSE THE LAKE FOR GREATEST
ACCUMULATIONS TONIGHT/MON WITH POSSIBLE LOCALIZED 6-11 INCH AMOUNTS.
IF SOMETHING SETS UP AND REMAINS STATIONARY...COULD EASILY SEE OVER
A FOOT OF SNOW. OVER THE W...BITTER COLD ARCTIC AIR IS MORE LIKELY
TO ELIMINATE DGZ ALTOGETHER...RESULTING IN VERY SMALL SNOWFLAKES AND
LIMITING SNOW ACCUMULATIONS TO PROBABLY NOTHING MORE THAN 1-2 TO
PERHAPS 3 INCHES PER 12HR PERIOD. LOCALIZED ACCUMULATIONS OF MAYBE
4-5 INCHES WILL BE POSSIBLE IN THE EXPECTED CONVERGENCE ZONE IN
ONTONAGON COUNTY. RATHER THAN SNOW ACCUMULATIONS...THE BIGGER
CONCERN WILL BE VERY LOW VIS AS THE SMALL SNOWFLAKES WILL BE
EXTREMELY EFFECTIVE AT REDUCING VISIBILITY. MAY END UP WITH VERY LOW
VIS/NEAR WHITE-OUT CONDITIONS WHENEVER SNOW SHOWERS PASS DUE TO THE
CONSIDERABLE AMOUNT OF FINE SNOWFLAKES IN THE AIR. THIS TYPE OF FINE
SNOW IS ALSO VERY EASILY BLOWN ABOUT BY VEHICLES...SO VIS ON ROADS
WILL BE ESPECIALLY LOW IN THE VCNTY OF OTHER VEHICLES...MAKING
TRAVEL DANGEROUS DESPITE THE LACK OF SIGNIFICANT SNOW ACCUMULATIONS.
CONSIDERING VIS IMPACTS RATHER THAN SNOW IMPACTS...WILL BE ISSUING A
WINTER WX ADVY FOR ONTONAGON/HOUGHTON/KEWEENAW THRU TUE MORNING TO
HIGHLIGHT VERY POOR VIS IN SHSN AND ALSO TO COVER WIND CHILLS WHICH
WILL BE FALLING TO AROUND THE WIND CHILL ADVY CRITERIA OF -25F.
OTHER CONCERN TONIGHT/MON WILL BE THE BITTER COLD AIR. POOL OF SUB
-30C AIR AT 850MB ADVECTING INTO THE UPPER LAKES MON SUGGESTS MOST
OF THE W HALF OF UPPER MI AWAY FROM IMMEDIATE LAKE SUPERIOR
INFLUENCE WILL STAY BLO ZERO DURING THE DAY MON. IN FACT...IT MAY BE
A STRUGGLE TO RISE MUCH ABOVE -10F ACROSS GOGEBIC COUNTY WHERE LAKE
MODERATION WILL BE LEAST. OTHERWISE...SINGLE DIGITS BLO ZERO SHOULD
BE THE RULE FOR HIGHS OVER THE W MON. WHILE IT`S OFTEN TOUGH TO KEEP
WINDS AOA THE 10MPH THRESHOLD AT NIGHT...CAA MAY BE ENOUGH TO KEEP
WINDS UP SUFFICIENTLY TO SATISFY WIND CHILL CRITERIA LATER TONIGHT.
HAVE EXPANDED WIND CHILL ADVY TO COVER ROUGHLY THE W HALF OF UPPER
MI OUTSIDE OF AFOREMENTIONED WINTER WX ADVY AREA.
.LONG TERM...(MONDAY NIGHT THROUGH SUNDAY)
ISSUED AT 455 PM EST SUN JAN 20 2013
AGREEMENT REMAINS GOOD IN THE LARGE SCALE PATTERN FOR THE UPCOMING
WEEK. MODELS ARE NOW EVEN IN OKAY AGREEMENT IN THEIR HANDLING OF
BREAKING DOWN THE DEEP TROUGH OVER THE AREA TO START THE WEEK AND
RESULTING SFC LOW MOVING FROM CENTRAL PLAINS ACROSS THE OHIO VALLEY
THURSDAY INTO FRIDAY.
BY LATE MONDAY GRIP OF COLD WILL BE IN FULL FORCE WITH H85 TEMPS
NEAR -30C OVER FAR WEST AND H95 TEMPS BLO -20C. NO REAL CHANGE TO
EXPECTED MSLP PATTERN WITH LAKE INDUCED TROUGHING AS FAR NORTH AS
EASTERN LK SUPERIOR WHILE HIGH PRESSURE IS CENTERED FROM SOUTHERN
SASKATCHEWAN INTO SOUTHERN MN AND IOWA. RESULT IS PERSISTENT
UNIDIRECTIONAL NW FLOW SFC-H5 ALLOWING LK EFFECT TO CONTINUE. AS IT
HAS APPEARED LAST COUPLE DAYS...MOST CONCENTRATED AND HEAVIEST LK
EFFECT WILL BE OVER FAR NORTHEAST CWA ALONG LK SUPERIOR...EAST OF
MUNISING TO NORTH OF SENEY AND NEWBERRY. AVAILABLE HIGHER RESOLUTION
MODELS STILL PEGGING QPF AMOUNTS OVER 0.20 INCH/12 HR FOR MON NIGHT
AND TUESDAY AND TUESDAY NIGHT. NO DOUBT CONVERGENCE WILL BE
MAXIMIZED DUE TO LARGE SCALE LAKE INDUCED TROUGHING AND ASSOCIATED
MESOLOW FORMING OVER SOUTHEAST LK SUPERIOR DUE TO LAND BREEZES OFF
UPR MICHIGAN AND ONTARIO. AS ALLUDED TO IN SHORT TERM DISCUSSION...
EXACTLY WHERE HEAVIER SNOW BANDS TIED TO THIS MESOSCALE FEATURE SET
UP IS HARD TO PIN DOWN.
MAIN ADJUSTMENT TO QPF/SNOW WAS TO KEEP HIGHER AMOUNTS CLOSER TO
SHORE THAN WHAT MODELS SHOW AS USUALLY LAND BREEZE DOMINATED
CONVERGENCE ZONE ENDS UP CLOSER TO THE LAKE THAN MODELS PORTRAY.
GIVEN THE VERY COLD AIRMASS...SLR/S WILL BE LESS THAN 15:1. OUTSIDE
OF AREAS WHERE STRONGEST CONVERGENCE/MOISTURE FLUXES OCCUR SLR/S
PROBABLY END UP MORE TOWARD 10:1 AS VERY FINE SNOWFLAKES DOMINATE.
SNOW AMOUNTS LIKELY END UP 3-5 INCHES EVERY 12 HRS UNDER DOMINATE
BAND IN THE EAST...BUT FOR REST OF AREAS FAVORED BY NW FLOW ALONG LK
SUPERIOR EXPECT JUST A FEW INCHES EVERY 12 HRS. DUE TO MODERATE SNOW
AMOUNTS SNOW AND POOR VSBY ALONG WITH POSSIBILITY OF DOMINATE BAND
ENHANCING SNOW AMOUNTS...COORD WITH SHORT TERM FORECASTER AND
EXTENDED LK EFFECT SNOW WARNING FOR EASTERN AREAS THROUGH 12Z
TUESDAY. FOR MOST LOCATIONS NEAR LK SUPERIOR IT WILL BE THE POOR VSBY
INSTEAD OF THE SNOW AMOUNTS THAT WILL BE THE HIGHER IMPACT ISSUE.
FREQUENT WHITEOUT CONDITIONS ARE EXPECTED AS THE SMALL SNOW FLAKES
FALLING WITH EVEN 10-20 MPH WINDS WILL BE VERY PROFICIENT IN LEADING
TO LOWER VSBY.
BITTER COLD WIND CHILLS ARE THE OTHER ISSUE EARLY THIS WEEK. AS IT
APPEARED YDY...TIGHTEST PRESSURE GRADIENT IS PRESENT TO BEGIN THE
LONG TERM BUT IT GRADUALLY RELAXES BY TUESDAY MORNING AND EVEN
FURTHER BY WEDNESDAY MORNING. EXPECT MIN TEMPS MONDAY NIGHT TO FALL
LESS THAN 10 BLO OVER A MAJORITY OF WEST HALF OF UPR MICHIGAN WITH
WIND CHILL READINGS DOWN TO 25-30 BLO ZERO. POSSIBLE THAT WINDS MAY
NOT TECHNICALLY REACH CRITERIA /SUSTAINED AT 10 MPH/ BUT IT IS
CERTAINLY CLOSE ENOUGH TO ISSUE A HEADLINE. AFTER COORD WITH SHORT
TERM FORECASTER...DECIDED TO ISSUE CATCH ALL WINTER WEATHER ADVY
OVER WESTERN TIER OF CWA FOR LK EFFECT SNOW/POOR VSBY AND THE BITTER
COLD WIND CHILLS. THIS HEADLINE WILL RUN THROUGH MIDDAY TUESDAY.
ELSEWHERE OVER WEST HALF OF UPR MICHIGAN...GOING TO ISSUE WIND CHILL
ADVY THROUGH MIDDAY TUESDAY. FURTHER REFINEMENTS MAY BE NEEDED TO
HEADLINES AS WE GET INTO MONDAY/TUESDAY...BUT THIS WILL BE OUR
STARTING POINT.
WORKING INTO TUESDAY NIGHT AND WEDNESDAY CONDITIONS CHANGE A BIT.
MAIN CHANGE IS BLYR WINDS BACKING MORE WSW TUESDAY NIGHT AND H925
WINDS BACKING WESTERLY. CHANGE IN WIND WILL PUSH ONGOING LK EFFECT
AND CLOUDS OVER THE WEST FARTHER TO THE NORTH. LK EFFECT STAYS IN
PLACE MOSTLY OVER THE EAST...STILL FALLING MODERATE AT TIMES...AS
THE STATIONARY MESOLOW REMAINS PRIMARY FEATURE DRIVING THE SNOW
THERE. THINKING THAT WITH WEAK PRESSURE GRADIENT AND LOSS OF CLOUDS
SHOULD ALLOW FOR WINDS OVER INTERIOR TO BECOME CALM AND PRIME
RADIATIONAL COOLING TO DEVELOP. LOWERED MIN TEMPS TOWARD LOWEST
GUIDANCE NUMBERS AROUND 20 BLO ZERO. MAY EVEN SEE LOWER TEMPS AT THE
FAVORED COLD SPOTS...BUT WILL JUST TREND IN THE COLDER DIRECTION FOR
NOW. ONLY CONCERN IN MIN TEMP FCST IS POSSIBLE INCREASING CLOUDS
ALOFT AHEAD OF ANOTHER TROUGH THAT DROPS IN ON WEDNESDAY. THINK
THOSE MID CLOUDS WILL HOLD OFF LONG ENOUGH TO ALLOW TEMPS TO TANK ON
TUESDAY NIGHT.
AS UPPER TROUGH BEGINS TO LOSE GRIP OVER AREA ON WEDNESDAY...MODELS
SHOWING SHORTWAVE DIPPING FROM NORTHERN PLAINS ON WEDNESDAY NIGHT TO
ACROSS LOWER GREAT LAKES LATER THURSDAY. MAJORITY OF SYNOPTIC SNOW
FROM THE SYSTEM PROBABLY MISSES UPR MICHIGAN...PERHAPS JUST TO THE
SOUTH THOUGH ACROSS WI AND LOWER MICHIGAN. INDICATION IS THAT FLOW
WILL BE SPLIT AND THE SOUTHERN SHORTWAVE DRIVES THE MAIN SYSTEM TO
THE SOUTH...BUT THERE IS ALSO NORTHERN STREAM WAVE DROPPING ACROSS
UPR LAKES THURSDAY NIGHT INTO FRIDAY. THIS MAY KEEP AN INVERTED SFC
TROUGH WELL TO NORTHWEST OF MAIN SFC LOW WHICH COULD LEAD TO SCT
SNOW SHOWERS OVR UPR LAKES ENHANCED FURTHER BY ONSHORE FLOW OFF LK
SUPERIOR. CONSENSUS POPS LOOKED OKAY...BUT DID INCREASE THEM
WEDNESDAY NIGHT THROUGH THURSDAY NIGHT NEAR LK SUPERIOR. BASED ON
MSLP AND H85 RH/TEMPS...LK EFFECT CONTINUES THROUGH FRIDAY AND
EVEN INTO SATURDAY OVER THE EASTERN CWA...THOUGH INCREASING LOW-MID
LEVEL RIDGING WILL LEAD TO INCREASINGLY HOSTILE CONDITIONS FOR THE
LK EFFECT.
HEIGHTS FURTHER FLATTEN OUT THROUGH NEXT WEEKEND LEADING TO WARMER
AIR SPILLING ACROSS NORTHERN PLAINS AND UPR LAKES. COULD BE WARM AIR
ADVECTION TYPE SYSTEM SNOW BUT GFS AND ECMWF DIFFER ON TRACK OF
SHORTWAVE AND SFC TROUGH TO ENHANCE THAT SNOW POTENTIAL /ECMWF
FARTHER NORTH WHILE GFS MOVES FOCUS ACROSS UPR MICHIGAN/ SO WILL NOT
ALTER THE SLIGHT CHANCES THAT CONSENSUS GAVE FOR POPS. AFTER A
BITTER COLD START TO THE WEEK...APPEARS THAT TEMPS TO END THE WEEK
INTO NEXT WEEKEND WILL SHOW WARMING TREND WITH READINGS CLOSE TO
NORMAL BY NEXT SUNDAY.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY AFTERNOON)
ISSUED AT 1246 PM EST SUN JAN 20 2013
NORTHWEST FLOW CONTINUES TO BRING LAKE EFFECT SNOW SHOWERS TO THE
TAF SITES...CHIEFLY CMX AND IWD. EXPECTATION IS THAT CIGS WILL
REMAIN FAIRLY STEADY AT MVFR THROUGH MUCH OF THE PERIOD FOR IWD AND
CMX. BLOWING SNOW SHOULD DIMINISH FOR THE MOST PART AT CMX AS WINDS
RELAX THIS AFTERNOON...BUT AN UPTICK IN LES INTENSITY THIS EVENING
WILL BRING VIS TO CONSISTENT LIFR LEVELS. MEANWHILE...BACKING WINDS
TO A MORE WESTERLY DIRECTION WILL KEEP THE MAJORITY OF LES ACTIVITY
JUST NORTH OF IWD.
FOR SAW...DO NOT EXPECT MUCH MORE THAN A FEW SNOW SHOWERS OFF AND ON
THROUGHOUT THE PERIOD. EXPECTING MAINLY BROKEN CLOUDS PUSHING UP TO
VFR CIGS...BUT THERE COULD BE EXTENDED PERIODS WHERE CLOUDS SCATTER
OUT.
&&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 455 PM EST SUN JAN 20 2013
NW WINDS OF 15-30KT WILL DOMINATE LAKE SUPERIOR TONIGHT THRU MON AS
INCREASINGLY COLDER ARCTIC AIR FLOWS OVER THE LAKE. ONLY EXCEPTION
WILL BE OVER THE FAR E WHERE LAND BREEZES OFF UPPER MI AND ONTARIO
MAY YIELD A SHARP SFC TROF OR MESOLOW. AS A RESULT...WINDS MAY SHIFT
TO A LIGHTER OFFSHORE DIRECTION EAST OF GRAND MARAIS TONIGHT WHILE
LAND BREEZE E TO NE WINDS PUSH OVER THE LAKE FROM ONTARIO INTO THE
AREA S OF CARIBOU ISLAND. SFC TROF/MESO LOW WILL MOVE S OR SE MON...
BRINGING STRONGER N OR NW WINDS BACK TO THAT AREA. HVY FREEZING
SPRAY WILL CONTINUE UNDER BITTER COLD AIR FLOWING INTO THE AREA.
EXPECT WINDS TO STAY IN THE 20 TO 30 KT RANGE THROUGH MIDDLE OF WEEK
THEN WINDS FINALLY RELAX AS HIGH PRESSURE BEGINS TO BUILD ACROSS REGION.
HEAVY FREEZING SPRAY WILL SUBSIDE...BUT NOT UNTIL WEDNESDAY NIGHT.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
WINTER WEATHER ADVISORY UNTIL 1 PM EST TUESDAY FOR MIZ001>003-
084.
LAKE EFFECT SNOW WARNING UNTIL 7 AM EST TUESDAY FOR MIZ006-007-
085.
WIND CHILL ADVISORY FROM 1 AM EST /MIDNIGHT CST/ MONDAY TO 1 PM
EST /NOON CST/ TUESDAY FOR MIZ004-005-009>011.
LAKE SUPERIOR...
HEAVY FREEZING SPRAY WARNING UNTIL 7 PM EST /6 PM CST/ WEDNESDAY
FOR LSZ162-240>251-263>267.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...ROLFSON
LONG TERM...JLA
AVIATION...TK
MARINE...ROLFSON/JLA
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
1247 PM EST SUN JAN 20 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 512 AM EST SUN JAN 20 2013
00Z RAOBS/LATEST WV IMAGERY AND RUC ANALYSIS SHOW HI AMPLITUDE UPR
TROF DOMINATING MOST OF CNTRL AND ERN NAMERICA DOWNWIND OF RDG ALONG
THE W COAST. COLDEST AIRMASS OF THE SEASON HAS SURGED INTO THE UPR
LKS IN THE WAKE OF POTENT SHRTWV/SFC LO NOW MOVING INTO SE ONTARIO
ON THE HEELS OF NW WINDS GUSTS TO ARND 50KT AS OBSVD AT SOME OF THE
HIER MARINE PLATFORMS. BUT WITH PASSAGE OF MAIN PRES RISE CENTER
EARLY THIS MRNG...THE SHARP CYC NW FLOW IS BEGINNING TO WEAKEN. 00Z
H85/H5 TEMPS WERE AS LO AS -25C/-40C AT YPL. NO SURPRISE THIS
INCOMING AIRMASS IS ALSO QUITE DRY WITH PWATS AOB 0.10 INCH. BUT
PASSAGE OF THIS FRIGID AIRMASS OVER THE RELATIVE WARM WATERS OF LK
SUP HAS RESULTED IN PLENTY OF LK CLDS AND LES...PRIMARILY IN THE NW
WIND SN BELTS E OF MQT AND OVER THE W. EVEN THOUGH WINDS ARE
BEGINNING TO DIMINISH...LINGERING GUSTY WINDS ARE BLOWING THE FINE
SN FLAKES AND RESULTING IN SHAPRLY REDUCED VSBY AS LO AS 1/4SM AT
SOME PLACES. TWO MORE SHRTWVS ARE DIGGING SEWD THRU SCNTRL CANADA
IN THE NW FLOW ALF ON CYC SIDE OF SHARP UPR JET AXIS ON THE WRN
FLANK OF THE DEEP TROF. OF THESE TWO...THE ONE FARTHER W IN
ALBERTA/SASKATCHEWAN LOOKS THE MOST IMPRESSIVE WITH 100KT H5 JET MAX
SHOWN IN NE BRITISH COLUMBIA AT 00Z.
TODAY...AS DEEP SHRTWV/SFC LO TO THE E EXIT FARTHER AWAY...PRES
GRADIENT WL SLACKEN AND WINDS DIMINISH. BUT LES WL CONTINUE MAINLY
IN THE NW WIND SN BELTS WITH ARRIVAL OF COLDER AIR/H85 TEMPS FALLING
TOWARD -25C OVER THE W BY 00Z DESPITE SOME MID LVL DRYING/
STRENGTHENING INVRN ARND 5K FT OVER THE W BUT AS HI AS 7-8FT OVER
THE E. THE LO H85 TEMPS WL LIMIT SN GROWTH AND RESULT IN FINE SN
FLAKES. THIS EFFECT SHOULD BE MAGNIFIED WITH SHORTER FETCH/LESS
MOISTENING OVER THE W BUT MITIGATED A BIT OVER THE E WITH LONGER
FETCH LENGTH. ALTHOUGH WINDS WL DIMINISH... SOME BLSN WL CONT
ESPECIALLY IN OPEN AREAS NEAR LK SUP AS THE FINE FLAKES WL BE BLOWN
EFFICIENTLY. WITH ARRIVAL OF FIRST OF 2 SHRTWVS UPSTREAM/
ACCOMPANYING DPVA...LLVL FLOW IS PROGGED TO BACK A BIT THIS
AFTN...WITH SOME MID LVL MOISTENING/INCRSG CONVECTIVE DEPTH SHOWING
UP AGAIN BY LATE THIS AFTN OVER THE W. EXPECT LTL DIURNAL RISE IN
TEMP WITH SURGE OF LLVL COLD AIR.
TONIGHT...2ND SHRTWV UPSTREAM/ACCOMPANYING DPVA ARE PROGGED TO
ARRIVE...WITH WEAKENING AND RISING INVRN/DEEPENING MSTR. AS CYC WNW
FLOW SHARPENS AS WELL...EXPECT INCRSG INTENSITY OF SHSN/BLSN. BULK
OF NUMERICAL MODELS SHOW SHARPEST LLVL CNVGC NEAR ONTONAGON COUNTY
AND IN AREAS NEAR LK SUP E OF MUNISING DUE TO LAND BREEZE EFFECTS
AND PERSISTENT LK INDUCED TROFFING OVER ERN LK SUP. WL FOCUS HIER
POPS/SN AMOUNTS IN THESE AREAS...ESPECIALLY OVER THE E WHERE LONGER
FETCH/MORE LK WARMING/MOISTENING WL IMPROVE SN/WATER RATIOS.
ALTHOUGH THE HEAVIER SHSN MIGHT DRIFT OUT OF NRN SCHOOLCRAFT COUNTY
LATE TNGT WITH BACKING FLOW...OPTED TO KEEP GOING WARNING FOR THE
ERN CWA GOING THRU 12Z MON. EXPECTED SN FALL OVER ONTONAGON COUNTY
LOOKS AT 4 TO 6 INCHES. SINCE THIS IS A MARGINAL ADVY AMOUNT AND
THERE IS LIKELY TO BE A BREAK IN THE SHSN/BLSN INTENSITY TODAY FOR
AT LEAST A TIME...DECIDED NOT TO EXTEND THE HEADLINE FOR ONTONAGON
COUNTY INTO TNGT. ANOTHER CONCERN WL BE POTENTIAL FOR AT LEAST ADVY
THRESHOLD WIND CHILLS AS THIS SHRTWV DRAGS H85 TEMPS AS LO AS -30C
TO IWD BY 12Z MON. SINCE THE H925 FLOW WL BE 280-290 DEGREES...CAD
WL ALLOW FOR MORE MIXING OF THE 20-25KT H925 WINDS...AND NEAR SFC
FLOW WL BACK FURTHER AND ALLOW FOR ADVECTION OF MORE UNMODIFIED
ARCTIC AIR DUE TO LAND BREEZE COMPONENT WITHIN BITTERLY COLD
AIRMASS...EXPECT WIND CHILLS TO FALL INTO THE ADVY RANGE AT LEAST
NEAR THE WI BORDER.
.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 512 AM EST SUN JAN 20 2013
GOING INTO MON...A TROUGH WILL ROTATE THROUGH THE CWA DURING THE
DAY. MODELS SHOW THAT DYNAMICS WITH THE TROUGH WILL NOT BRING MUCH
IF ANYTHING IN THE WAY OF SYNOPTIC SNOW...BUT WILL ACT TO INTENSIFY
NW WIND LES AND CAUSE THE SFC TROUGH OVER ERN LAKE SUPERIOR TO CLOSE
OFF. HIGHER RES MODELS SUGGEST THAT THE LOW WILL FOCUS LES BANDS
INTO A MORE DOMINANT BAND MOVING ONSHORE ACROSS ALGER AND/OR LUCE
COUNTIES...DEPENDING ON MESOSCALE CONDITIONS THAT WILL HAVE TO BE
DETERMINED MUCH CLOSER TO THE TIME OF OCCURRENCE. GIVEN 725MB
INVERSION TOP TEMPERATURES AROUND -35C AND LAKE WATER TEMPS AROUND
2C...LAKE INDUCED EQUILIBRIUM LEVELS OF 12-15KFT SHOULD BE REALIZED
OVER ERN LAKE SUPERIOR. THE DGZ WILL BE VERY LOW...SO SLR/S WILL NOT
BE AS HIGH AS THE COULD BE IN WARMER CONDITIONS. EVEN SO...IF A
HEAVIER BAND DOES FORM...SNOWFALL RATES COULD APPROACH AN INCH AN
HOUR UNDER THE BAND. OVER WRN LAKE SUPERIOR...INVERSION TOPS WILL
NOT BE AS HIGH FARTHER AWAY FROM THE TROUGH.
THE REALLY COLD AIR /850MB TEMPS -27C TO -30C/ BEGINS TO PUSH E LATE
TUE...SO THE COLDEST SFC TEMPS OF THE SEASON /AREA WIDE/ WILL BE MON
THROUGH TUE NIGHT...WITH A CONCERN OF WIND CHILLS. WIND CHILL
ADVISORY CRITERIA IS WIND CHILLS LESS THAN -25F WITH WINDS AT LEAST
10MPH...WHICH SHOULD BE REACHED OVER PORTIONS OF THE WRN HALF OF THE
U.P. SUN NIGHT THROUGH MON AND AGAIN TUE NIGHT /MON NIGHT THE WINDS
ARE FORECAST TO BE BELOW THE 10MPH CRITERIA/. WARNING CRITERIA OF
-35F SHOULD BE HARDER TO ACHIEVE...WITH THE BEST CHANCE OF
OCCURRENCE SUN NIGHT INTO MON MORNING AND MON NIGHT INTO TUE MORNING
OVER THE FAR W. COLDEST ACTUAL TEMPS LOOK TO BE MON NIGHT OVER
PORTIONS OF GOGEBIC AND IRON COUNTIES WITH A LOW FORECAST OF -20F.
DECIDED TO ISSUE WIND CHILL ADVISORY FOR THE FAR W MON.
LOW LEVEL TEMPS GENERALLY WARM SLOWLY TO -15C TO -20C BY SAT WITH NW
LOW LEVEL WINDS THROUGH MOST OF THE PERIOD. A SHORTWAVE LOOKS TO
MOVE THROUGH ON WED...SO LES SHOULD BE INTENSIFIED THEN...BUT
OTHERWISE MORE RIDGING WORKS INTO THE AREA THROUGH THE REST OF THE
PERIOD...MAKING FOR MORE HOSTILE CONDITIONS FOR LES THU THROUGH SAT.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY AFTERNOON)
ISSUED AT 1246 PM EST SUN JAN 20 2013
NORTHWEST FLOW CONTINUES TO BRING LAKE EFFECT SNOW SHOWERS TO THE
TAF SITES...CHIEFLY CMX AND IWD. EXPECTATION IS THAT CIGS WILL
REMAIN FAIRLY STEADY AT MVFR THROUGH MUCH OF THE PERIOD FOR IWD AND
CMX. BLOWING SNOW SHOULD DIMINISH FOR THE MOST PART AT CMX AS WINDS
RELAX THIS AFTERNOON...BUT AN UPTICK IN LES INTENSITY THIS EVENING
WILL BRING VIS TO CONSISTENT LIFR LEVELS. MEANWHILE...BACKING WINDS
TO A MORE WESTERLY DIRECTION WILL KEEP THE MAJORITY OF LES ACTIVITY
JUST NORTH OF IWD.
FOR SAW...DO NOT EXPECT MUCH MORE THAN A FEW SNOW SHOWERS OFF AND ON
THROUGHOUT THE PERIOD. EXPECTING MAINLY BROKEN CLOUDS PUSHING UP TO
VFR CIGS...BUT THERE COULD BE EXTENDED PERIODS WHERE CLOUDS SCATTER
OUT.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 512 AM EST SUN JAN 20 2013
EXPECT NW GALES TO 40 KTS THIS MORNING OVER MAINLY THE E HALF TO
DIMINISH BY EARLY AFTERNOON AS LO PRES OVER SE CANADA CONTINUES TO
MOVE FARTHER TO THE E. BUT WITH ARCTIC AIR DOMINATING INTO MID
WEEK...THERE WILL BE PERIODS OF HEAVY FREEZING SPRAY EVEN THOUGH THE
NW WINDS WILL BE MAINLY IN THE 15 TO 30 KT RANGE. THE ARRIVAL OF A
WEAKER PRES GRADIENT/LIGHTER WINDS BY LATER WED/THU WILL FINALLY END
THE THREAT OF HEAVY FREEZING SPRAY.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
LAKE EFFECT SNOW WARNING UNTIL 7 AM EST MONDAY FOR MIZ006-007-
085.
WIND CHILL ADVISORY FROM 3 AM TO 6 PM CST MONDAY FOR MIZ009.
WIND CHILL ADVISORY FROM 4 AM EST /3 AM CST/ TO 1 PM EST /NOON
CST/ MONDAY FOR MIZ002-010.
LAKE SUPERIOR...
HEAVY FREEZING SPRAY WARNING UNTIL 7 PM EST TUESDAY FOR
LSZ245>251-265>267.
GALE WARNING UNTIL 1 PM EST THIS AFTERNOON FOR LSZ245>251-
265>267.
HEAVY FREEZING SPRAY WARNING UNTIL 7 PM EST /6 PM CST/ MONDAY
FOR LSZ162-240>244-263-264.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...KC
LONG TERM...TITUS
AVIATION...TK
MARINE...KC
AREA FORECAST DISCUSSION
NWS HASTINGS NE
1243 PM CST SUN JAN 20 2013
.UPDATE...JUST SHIPPED ANOTHER UPDATE ADDRESSING ONLY THIS
AFTERNOON...AS LATEST OBSERVATIONS AND SHORT TERM MODELS/GUIDANCE SUCH
AS HRRR AND GFS LAMP UNFORTUNATELY CONFIRM THAT MORE CUTS IN HIGH
TEMPERATURES WERE NEEDED ACROSS THE CWA. IN GENERAL...TOOK ANOTHER
2-5 DEGREES OFF NEARLY ALL AREAS...MEANING THAT HIGHS ARE NOW
FORECAST TO END UP GENERALLY 5-10 DEGREES COOLER THAN ORIGINAL
EARLY MORNING FORECAST. THIS NOW MEANS THAT ROUGHLY THE NORTHEAST 1/2
OF THE CWA IS UNLIKELY TO REACH 30...WITH FAR NORTH/NORTHEAST
COUNTIES UNLIKELY TO REACH 25. ACROSS SOUTHWESTERN-MOST NEB ZONES
AND NORTH CENTRAL KS...MOST AREAS ARE NOW EXPECTED TO TOP OUT
SOMEWHERE IN THE 30S...WITH ANY LOW 40S MOST FAVORED IN SOUTHERN
PARTS OF ROOKS/OSBORNE COUNTIES. OTHERWISE...OTHER ELEMENTS OF
AFTERNOON FORECAST REMAIN LARGELY ON TRACK...WITH NORTH WINDS
EVENTUALLY PICKING UP TOWARD 10-20 MPH ESPECIALLY NEAR/AFTER 3 PM
AND SKIES CONTINUING TO AVERAGE MOSTLY CLOUDY DUE TO A COMBINATION
OF PASSING MID-HIGH CLOUDS AND GRADUALLY INCREASING PATCHES OF
LOWER CLOUDS.
&&
.PREV DISCUSSION... /ISSUED 1130 AM CST SUN JAN 20 2013/
AVIATION...18Z KGRI TAF. CONFIDENCE IN CEILING TRENDS IS NOT ALL
THAT HIGH THROUGH THE NEXT 24 HOURS...BUT ITS LOOKING INCREASINGLY
LIKELY THAT A GOOD CHUNK OF THIS TIME FRAME COULD BE DOMINATED BY
AN MVFR CEILING. LATEST VISIBLE SATELLITE AND SHORT TERM MODEL
TRENDS INDICATE THAT MVFR CLOUDS SOMEWHERE BETWEEN 1500 AND 3000
FT AGL SHOULD DEVELOP INTO THE TERMINAL AREA EARLY THIS
AFTERNOON...AND COULD VERY WELL STICK AROUND ON AT LEAST AN OFF/ON
BASIS THROUGH THE REST OF THE PERIOD. INSTEAD OF TRYING TO PIN
DOWN ANY POSSIBLE TIME FRAMES WHERE CEILING MIGHT LIFT OR SCATTER
INTO VFR...WILL SIMPLY KEEP A PREVAILING MVFR TREND GOING FOR
NOW...KNOWING THAT FUTURE UPDATES/DISCUSSIONS WILL ADDRESS THE
LATEST SHORT TERM TRENDS. THERE IS EVEN SOME INDICATION THAT THE
LATTER HALF OF THE PERIOD COULD SEE CEILINGS DROP TOWARD IFR
LEVELS...BUT CONFIDENCE IS NOT HIGH ENOUGH TO GO THIS LOW YET. AS
FOR VISIBILITIES...CONFIDENCE REMAINS RATHER HIGH IN CONTINUED
VFR. SURFACE BREEZES WILL START OUT LIGHT/VARIABLE BEFORE AT LEAST
A BRIEF PERIOD OF STRONGER NORTH WINDS MOVE IN THIS AFTERNOON WITH
GUST POTENTIAL 15-20KT. A GENERALLY NORTH BREEZE NEAR/LESS THAN
10KT SHOULD THEN PREVAIL THIS EVENING THROUGH MONDAY MORNING.
FINALLY...WILL LEAVE OUT ANY MENTION OF SNOW...ALTHOUGH A FEW
FLURRIES CANNOT BE RULED OUT LATE TONIGHT INTO MONDAY MORNING.
PREV DISCUSSION... /ISSUED 1046 AM CST SUN JAN 20 2013/
UPDATE...FOR NOT HAVING HIGH IMPACT WEATHER...TODAY/S FORECAST
REMAINS CHALLENGING ESPECIALLY REGARDING TEMPERATURE TRENDS.
ALTHOUGH CONFIDENCE IN THE HOURLY DETAILS REMAINS SOMEWHAT BELOW
AVERAGE...THE OVERALL MESSAGE FROM VARIOUS MODEL/GUIDANCE SOURCES
SUCH AS HRRR...RAP AND GFS LAMP STRONGLY SUGGESTED THAT PREVIOUS
HIGHS WERE AT LEAST A BIT TOO WARM. AS A RESULT...TRIMMED AT LEAST
1-2 DEGREES OFF HIGHS FOR GENERALLY THE SOUTHWESTERN 2/3 OF THE
CWA...BUT MADE MORE SIGNIFICANT 5-7 DEGREE CUTS TO ESPECIALLY THE
NORTHEAST 1/4 OF OUR AREA...OR ESPECIALLY NORTHEAST OF AN ORD-YORK
LINE. IN THESE NORTHEAST AREAS...TEMPS WILL BE LUCKY TO REACH THE
MID-UPPER 20S...WHILE AT LEAST LOW-MID 30S STILL LOOK POSSIBLE
ACROSS MOST OF THE REMAINDER OF OUR NEB ZONES. KS ZONES COULD
STILL MAKE A RUN AT THE LOW 40S...ALTHOUGH EVEN HERE MAY CONSIDER
LOWERING A BIT IN A FUTURE UPDATE. OTHERWISE...A GENERALLY LIGHT
AND VARIABLE WIND REGIME WILL REMAIN IN PLACE ALL AREAS UNTIL AT
LEAST EARLY AFTERNOON...BUT THEREAFTER A GRADUAL INCREASE IN
NORTHERLY SPEEDS WILL START OVERTAKING THE CWA FROM WEST TO
EAST...WITH AT LEAST A SHORT PERIOD OF 20+ MPH GUSTS EXPECTED TO
AFFECT MOST ALL AREAS BY MID-LATE AFTERNOON. PRECIP-WISE...WILL
CONTINUE TO LEAVE FLURRIES OUT OF THIS AFTERNOON/S FORECAST FOR
OUR FAR NORTHEAST COUNTIES...AS RADAR TRENDS AND SHORT TERM MODELS
CONTINUE TO SUGGEST THAT ANY SUCH ACTIVITY SHOULD LARGELY SLIDE BY
JUST TO OUR NORTHEAST.
PREV DISCUSSION... /ISSUED 414 AM CST SUN JAN 20 2013/
SHORT TERM...TODAY THROUGH TUESDAY NIGHT. PRIMARY FORECAST
CONCERN LIES WITH TEMPERATURES.
QUIET CONDITIONS REMAIN IN PLACE ACROSS THE REGION EARLY THIS
MORNING...WITH SATELLITE AND UPPER AIR PROFILER DATA SHOWING
NORTHWESTERLY FLOW IN PLACE. RIDGING CONTINUES ALONG THE WEST
COAST...WHILE A COUPLE OF DISTURBANCES WORK THEIR WAY THROUGH THE
NWRLY FLOW...ONE OVER THE GREAT LAKES REGION AND THE OTHER OVER SC
CANADA. AT THE SURFACE...HIGH PRESSURE CONTINUES TO SLIDE SOUTH
OUT OF THE DAKOTAS INTO THE AREA...BEHIND A COLD FRONT WHICH
PASSED THROUGH THE REGION LATE SAT AFTN/EVENING. WITH TIME...WINDS
HAVE GRADUALLY BECOME MORE EASTERLY ACROSS THE CWA...AND HAVE
DIMINISHED IN SPEED.
LOOKING AT THE REST OF TODAY AND INTO MONDAY...THE MAIN STORY LIES
WITH THE PASSAGE OF YET ANOTHER COLD FRONT...AND ITS AFFECT ON
TEMPERATURES. MODELS REMAIN IN GOOD AGREEMENT SHOWING THE ABOVE
MENTIONED UPPER LEVEL DISTURBANCE OVER SC CANADA CONTINUING TO
SLIDE SOUTHEAST THROUGH THE DAY TODAY...WITH THE TIMING OF THE
ACCOMPANYING SFC COLD FRONT/NORTHWESTERLY WINDS STILL EXPECTED TO
PASS THROUGH THE CWA DURING THE AFTERNOON HOURS. THE TIMING MAKES
TEMPERATURES TODAY PRETTY DIFFICULT...ESP WITH MODELS/GUIDANCE NOT
IN VERY GOOD AGREEMENT...MAINLY FOR THOSE NORTHWESTERN PORTIONS OF
THE CWA...WHICH WILL PROB SEE THEIR HIGHS CLOSER TO MIDDAY/EARLY
AFTN VS MID AFTN FURTHER SOUTH. OVERALL DIDNT MAKE MANY CHANGES TO
THE INHERITED FORECAST...WHICH CONTINUES TO CALL FOR GENERALLY MID
30S ACROSS SC NEB...WITH LOWER 40S IN NC KS. CERTAINLY SOMETHING
FOR THE DAYSHIFT TO KEEP AN EYE ON.
AS FAR AS THE POSSIBILITY OF FLURRIES GOES...DECIDED TO KEEP THE
MENTION OUT OF THE FORECAST. AS THAT DISTURBANCE SWINGS SOUTH...IT
WILL BRING ALONG MORE CLOUD COVER AND COLDER TEMPERATURES...AND
WHILE MODELS DO SHOW SOME BATCHES OF INCREASED LOWER LEVEL /BELOW
700MB/ MOISTURE MOVING INTO THE REGION...MAINLY THIS
AFTERNOON...THERE IS ALSO PRETTY GOOD AGREEMENT WITH KEEPING THE
BETTER RH AND COLDER TEMPS MORE FAVORABLE FOR FLURRIES
NORTH/NORTHEAST OF THE CWA...BARELY. THE OPER NAM/GFS/EC CONTINUE
TO SHOW THE CWA DRY...AS DOES THE HRRR. THE RAP AND ONE RUN OF THE
4 KM SHOW PERHAPS THE FAR N/NE EDGE OF THE CWA MAYBE SEEING A
FEW...BUT AM GOING TO CONTINUE TO EXCLUDE THE MENTION.
REALLY THE BRUNT OF THE COLDER AIR HOLDS OFF FROM MOVING INTO THE
CWA UNTIL LATER TODAY AND MAINLY THIS EVENING/TONIGHT. AS HAS BEEN
THE CASE OVER THE PAST FEW DAYS...MODELS CONTINUE TO SHOW THE
MAIN AXIS OF THE TROUGH...AND THUS THE COLDEST AIR...SETTING UP
JUST EAST OF THE CWA TONIGHT/THROUGH MONDAY. WHILE THE CWA MAY
CATCH A BRIEF BREAK FROM CLOUD COVER TONIGHT...EXPECTING TO SEE
ADDITIONAL CLOUD COVER /MAINLY UPPER LEVEL/ STREAMING IN FROM THE
NORTHWEST...KEEPING MAINLY THE NORTHEASTERN HALF OF THE CWA UNDER
PARTLY/MOSTLY CLOUDY SKIES ON MONDAY. DIDNT MAKE ANY NOTABLE
CHANGES TO MONDAYS HIGHS...WHICH RANGE FROM THE LOWER 20S IN THE
NORTHEAST TO LOWER 30S IN THE SOUTHWEST. SURFACE HIGH PRESSURE
SLIDING IN FROM THE NORTHWEST WILL BRING FAIRLY LIGHT WINDS FOR
MOST LOCATIONS.
MONDAY NIGHT THROUGH TUESDAY...THE MAIN UPPER LEVEL TROUGH/COLDEST
AIR ALREADY STARTS ITS EASTWARD SHIFT MONDAY NIGHT...WHICH WILL
BRING A REBOUND IN TEMPS FOR TUESDAY. THE POSSIBILITY OF GETTING
CLIPPED IN THE NORTH BY MORE FLURRIES OR LIGHT SNOW WILL BE
SOMETHING TO CONSIDER WITH UPCOMING MODEL RUNS. CURRENTLY AM
KEEPING THE MENTION OUT OF THE FORECAST...WITH MODELS SHOWING THE
COLDER TEMPS AND BETTER POTENTIAL /MAINLY MONDAY NIGHT INTO THE
FIRST HALF OF TUESDAY/...DRIVEN BY A STRONG UPPER LEVEL JET
STREAK NOSING IN FROM THE N/NW...REMAINING ONCE AGAIN JUST OUTSIDE
THE N/NE EDGE OF THE CWA. WITH THE WARMER AIR STARTING TO BUILD
BACK IN FROM THE WEST...HIGHS CURRENTLY RANGE FROM THE UPPER 20S
IN THE NORTHEAST TO LOWER 40S IN THE WEST...AND SOME MODELS
SUGGEST THE WEST SHOULD BE WARMER. OVERNIGHT LOWS EXPECTED TO
REBOUND FROM THE SINGLE DIGITS/TEENS MONDAY NIGHT TO THE
TEENS/NEAR 20 TUESDAY NIGHT.
LONG TERM...(WEDNESDAY THRU SATURDAY)
THE MAIN STORY: BONE DRY PATTERN CONTINUES WITH RE-AMPLIFYING NW
FLOW STUNTING TEMP RECOVERY...BUT SIGNALS CONTINUE FOR SOME PRECIP
POTENTIAL VERY LATE THIS MONTH.
PATTERN: THE HIGHLY AMPLIFIED WRN N AMERICA RIDGE/ERN TROF WILL
MEET ITS DEMISE NEXT WEEK AS A PACIFIC SHRTWV TROF MOVES ONSHORE
IN THE PAC NW WED AND MOVES THRU THE RIDGE. AS THIS TROF MOVES
INTO THE LGWV TROF THU-FRI...THE PATTERN WILL RE-AMPLIFY
SOMEWHAT...CURBING OUR WARM-UP FRI-SAT. RIDGING THEN ADVANCES OVER
THE PLAINS NEXT WEEKEND...FOLLOWED BY LOWERING HGTS OVER WRN N
AMERICA THE LAST WEEK OF JAN...SUGGESTING A PERIOD OF STORMINESS
AND PCPN POTENTIAL.
MODELS: THERE IS GOOD AGREEMENT AMONGST THE 00Z EC/GFS/GEM ON THIS
SCENARIO THRU 00Z/SAT. THE ONE CAVEAT...THE OPERATIONAL 18Z/00Z GFS
ARE NOT AS AMPLIFIED WITH THE TEMPORARILY REINVIGORATED RIDING OVER
WRN N AMERICA. IN FACT...THE GFS ENSEMBLE MEAN IS CLOSER TO THE
MORE AMPLIFIED 12Z/00Z EC CYCLES. THIS FCST INCORPORATES
EC/GFS/GEM/HPC GUIDANCE THRU 00Z/SAT. BEYOND THAT ITS HPC/EC AND
EC/GFS ENSEMBLE MEANS.
TEMPS: ESSENTIALLY NEAR NORMAL THRU SAT WITH ONE DAY OF BELOW
NORMAL FRI.
HAZARDS: NONE ENVISIONED ATTM.
UPCOMING PCPN OPPORTUNITIES: NOTHING NOTABLE THRU AT LEAST SAT AND
PROBABLY TO MON 1/28. HOWEVER...ODDS ARE INCREASING FOR A MDT
PCPN EVENT AS WE CLOSE THE BOOKS ON JAN.
THE DAILY DETAILS...
WED: M/SUNNY. PROBABLY NEAR NORMAL TEMPS. LEE TROF INTENSIFIES
WITH TROF MOVING INTO PAC NW...AIDING IN MODEST TEMP RECOVERY.
TEMP CONFIDENCE GRAPHICS SHOW ABOVE NORMAL SPREAD IN TEMPS.
THU: P/CLOUDY. A DRY COLD FRONTAL PASSAGE IN THE PRE-DAWN HRS. LOW
PRES EJECTS OUT OF CO ACROSS KS/OK. SOME DIFF/S IN TIMING REMAIN
WITH THE EC/GEM FASTER AND MORE POTENT THAN THE GFS. THE 00Z EC
ENSEMBLES HAVE COME INTO MUCH BETTER AGREEMENT ON SLP SINCE ITS
12Z RUN. HPC IS IN AGREEMENT SO WE/LL ROLL WITH THIS SCENARIO.
ABOVE NORMAL UNCERTAINTY IN TEMPS.
THU HAS POTENTIAL TO BE A BREEZY DAY. HOWEVER...SOME BAGGINESS IN
THE PRES TROF OF A REINFORCING SHOT OF COLD AIR COULD MITIGATE.
THU NGT: ANOTHER PUSH OF COLDER AIR MOVES THRU AS THE SHRTWV TROF
PASSES...BUT THE WORST OF IT REMAINS OFF TO THE N AND E.
FRI: P/CLOUDY. ARCTIC HIGH PRES EXPANDS OVER THE MS VALLEY. IF THE
EC IS RIGHT ANOTHER WEAK LOW MOVES THRU DELIVERING ANOTHER PUSH OF
MARGINALLY COLD AIR. CONFIDENCE IS ABOVE NORMAL ON A COOL DOWN.
TEMPS PROBABLY CLOSE TO 10F BELOW NORMAL.
SAT: SUNNY AS YET ANOTHER ARCTIC HIGH EXPANDS OVER THE MS VALLEY.
HGTS BEGIN RISING AS BROAD RIDGING ADVANCES TOWARD THE PLAINS. WAA
BEGINS WITH A NEW LEE TROF DEVELOPING.
BEYOND SAT...
A VERY NICE WARM-UP COMMENCES SUN THAT COULD LINGER INTO EARLY THE
FOLLOWING WEEK 1/28-29 DEPENDENT ON HOW THE PATTERN SHAPES UP.
WE COULD SEE 1 OR 2 DAYS OF MUCH ABOVE NORMAL TEMPS (+10F OR
MORE). IF WE ROLL WITH THE OPERATIONAL EC AND THE EC/GFS ENSEMBLES
LATE THIS WEEK...THEN WE MUST GO SLOWER THAN THE OPERATIONAL GFS
FOR EARLY THE FOLLOWING WEEK. THE GREATER AMPLIFIED SCENARIO WILL
SLOW THINGS DOWN UPSTREAM. EITHER WAY...THE NEXT PAC TROF WILL DIG
INTO THE DESERT SW THE LAST WEEK OF JAN. THIS IS A FAVORABLE SETUP
FOR A DECENT PCPN EVENT HERE AND WITH THE LOW TRACKING S OF THE
FCST AREA...THIS COULD END UP BEING THE WINTRY VARIETY. HOPEFULLY
WE/LL HAVE TIME TO ENTRAIN GOOD MSTR AFTER MULTIPLE EPISODES OF
CONTINENTAL POLAR AIR HAVE PLUNGED INTO THE GULF.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
KS...NONE.
&&
$$
UPDATES/AVIATION...PFANNKUCH
SHORT TERM...ADO
LONG TERM...HALBLAUB
AREA FORECAST DISCUSSION
NWS HASTINGS NE
1130 AM CST SUN JAN 20 2013
.AVIATION...18Z KGRI TAF. CONFIDENCE IN CEILING TRENDS IS NOT ALL
THAT HIGH THROUGH THE NEXT 24 HOURS...BUT ITS LOOKING INCREASINGLY
LIKELY THAT A GOOD CHUNK OF THIS TIME FRAME COULD BE DOMINATED BY
AN MVFR CEILING. LATEST VISIBLE SATELLITE AND SHORT TERM MODEL
TRENDS INDICATE THAT MVFR CLOUDS SOMEWHERE BETWEEN 1500 AND 3000
FT AGL SHOULD DEVELOP INTO THE TERMINAL AREA EARLY THIS
AFTERNOON...AND COULD VERY WELL STICK AROUND ON AT LEAST AN OFF/ON
BASIS THROUGH THE REST OF THE PERIOD. INSTEAD OF TRYING TO PIN
DOWN ANY POSSIBLE TIME FRAMES WHERE CEILING MIGHT LIFT OR SCATTER
INTO VFR...WILL SIMPLY KEEP A PREVAILING MVFR TREND GOING FOR
NOW...KNOWING THAT FUTURE UPDATES/DISCUSSIONS WILL ADDRESS THE
LATEST SHORT TERM TRENDS. THERE IS EVEN SOME INDICATION THAT THE
LATTER HALF OF THE PERIOD COULD SEE CEILINGS DROP TOWARD IFR
LEVELS...BUT CONFIDENCE IS NOT HIGH ENOUGH TO GO THIS LOW YET. AS
FOR VISIBILITIES...CONFIDENCE REMAINS RATHER HIGH IN CONTINUED
VFR. SURFACE BREEZES WILL START OUT LIGHT/VARIABLE BEFORE AT LEAST
A BRIEF PERIOD OF STRONGER NORTH WINDS MOVE IN THIS AFTERNOON WITH
GUST POTENTIAL 15-20KT. A GENERALLY NORTH BREEZE NEAR/LESS THAN
10KT SHOULD THEN PREVAIL THIS EVENING THROUGH MONDAY MORNING.
FINALLY...WILL LEAVE OUT ANY MENTION OF SNOW...ALTHOUGH A FEW
FLURRIES CANNOT BE RULED OUT LATE TONIGHT INTO MONDAY MORNING.
&&
.PREV DISCUSSION... /ISSUED 1046 AM CST SUN JAN 20 2013/
UPDATE...FOR NOT HAVING HIGH IMPACT WEATHER...TODAY/S FORECAST
REMAINS CHALLENGING ESPECIALLY REGARDING TEMPERATURE TRENDS.
ALTHOUGH CONFIDENCE IN THE HOURLY DETAILS REMAINS SOMEWHAT BELOW
AVERAGE...THE OVERALL MESSAGE FROM VARIOUS MODEL/GUIDANCE SOURCES
SUCH AS HRRR...RAP AND GFS LAMP STRONGLY SUGGESTED THAT PREVIOUS
HIGHS WERE AT LEAST A BIT TOO WARM. AS A RESULT...TRIMMED AT LEAST
1-2 DEGREES OFF HIGHS FOR GENERALLY THE SOUTHWESTERN 2/3 OF THE
CWA...BUT MADE MORE SIGNIFICANT 5-7 DEGREE CUTS TO ESPECIALLY THE
NORTHEAST 1/4 OF OUR AREA...OR ESPECIALLY NORTHEAST OF AN ORD-YORK
LINE. IN THESE NORTHEAST AREAS...TEMPS WILL BE LUCKY TO REACH THE
MID-UPPER 20S...WHILE AT LEAST LOW-MID 30S STILL LOOK POSSIBLE
ACROSS MOST OF THE REMAINDER OF OUR NEB ZONES. KS ZONES COULD
STILL MAKE A RUN AT THE LOW 40S...ALTHOUGH EVEN HERE MAY CONSIDER
LOWERING A BIT IN A FUTURE UPDATE. OTHERWISE...A GENERALLY LIGHT
AND VARIABLE WIND REGIME WILL REMAIN IN PLACE ALL AREAS UNTIL AT
LEAST EARLY AFTERNOON...BUT THEREAFTER A GRADUAL INCREASE IN
NORTHERLY SPEEDS WILL START OVERTAKING THE CWA FROM WEST TO
EAST...WITH AT LEAST A SHORT PERIOD OF 20+ MPH GUSTS EXPECTED TO
AFFECT MOST ALL AREAS BY MID-LATE AFTERNOON. PRECIP-WISE...WILL
CONTINUE TO LEAVE FLURRIES OUT OF THIS AFTERNOON/S FORECAST FOR
OUR FAR NORTHEAST COUNTIES...AS RADAR TRENDS AND SHORT TERM MODELS
CONTINUE TO SUGGEST THAT ANY SUCH ACTIVITY SHOULD LARGELY SLIDE BY
JUST TO OUR NORTHEAST.
PREV DISCUSSION... /ISSUED 414 AM CST SUN JAN 20 2013/
SHORT TERM...TODAY THROUGH TUESDAY NIGHT. PRIMARY FORECAST
CONCERN LIES WITH TEMPERATURES.
QUIET CONDITIONS REMAIN IN PLACE ACROSS THE REGION EARLY THIS
MORNING...WITH SATELLITE AND UPPER AIR PROFILER DATA SHOWING
NORTHWESTERLY FLOW IN PLACE. RIDGING CONTINUES ALONG THE WEST
COAST...WHILE A COUPLE OF DISTURBANCES WORK THEIR WAY THROUGH THE
NWRLY FLOW...ONE OVER THE GREAT LAKES REGION AND THE OTHER OVER SC
CANADA. AT THE SURFACE...HIGH PRESSURE CONTINUES TO SLIDE SOUTH
OUT OF THE DAKOTAS INTO THE AREA...BEHIND A COLD FRONT WHICH
PASSED THROUGH THE REGION LATE SAT AFTN/EVENING. WITH TIME...WINDS
HAVE GRADUALLY BECOME MORE EASTERLY ACROSS THE CWA...AND HAVE
DIMINISHED IN SPEED.
LOOKING AT THE REST OF TODAY AND INTO MONDAY...THE MAIN STORY LIES
WITH THE PASSAGE OF YET ANOTHER COLD FRONT...AND ITS AFFECT ON
TEMPERATURES. MODELS REMAIN IN GOOD AGREEMENT SHOWING THE ABOVE
MENTIONED UPPER LEVEL DISTURBANCE OVER SC CANADA CONTINUING TO
SLIDE SOUTHEAST THROUGH THE DAY TODAY...WITH THE TIMING OF THE
ACCOMPANYING SFC COLD FRONT/NORTHWESTERLY WINDS STILL EXPECTED TO
PASS THROUGH THE CWA DURING THE AFTERNOON HOURS. THE TIMING MAKES
TEMPERATURES TODAY PRETTY DIFFICULT...ESP WITH MODELS/GUIDANCE NOT
IN VERY GOOD AGREEMENT...MAINLY FOR THOSE NORTHWESTERN PORTIONS OF
THE CWA...WHICH WILL PROB SEE THEIR HIGHS CLOSER TO MIDDAY/EARLY
AFTN VS MID AFTN FURTHER SOUTH. OVERALL DIDNT MAKE MANY CHANGES TO
THE INHERITED FORECAST...WHICH CONTINUES TO CALL FOR GENERALLY MID
30S ACROSS SC NEB...WITH LOWER 40S IN NC KS. CERTAINLY SOMETHING
FOR THE DAYSHIFT TO KEEP AN EYE ON.
AS FAR AS THE POSSIBILITY OF FLURRIES GOES...DECIDED TO KEEP THE
MENTION OUT OF THE FORECAST. AS THAT DISTURBANCE SWINGS SOUTH...IT
WILL BRING ALONG MORE CLOUD COVER AND COLDER TEMPERATURES...AND
WHILE MODELS DO SHOW SOME BATCHES OF INCREASED LOWER LEVEL /BELOW
700MB/ MOISTURE MOVING INTO THE REGION...MAINLY THIS
AFTERNOON...THERE IS ALSO PRETTY GOOD AGREEMENT WITH KEEPING THE
BETTER RH AND COLDER TEMPS MORE FAVORABLE FOR FLURRIES
NORTH/NORTHEAST OF THE CWA...BARELY. THE OPER NAM/GFS/EC CONTINUE
TO SHOW THE CWA DRY...AS DOES THE HRRR. THE RAP AND ONE RUN OF THE
4 KM SHOW PERHAPS THE FAR N/NE EDGE OF THE CWA MAYBE SEEING A
FEW...BUT AM GOING TO CONTINUE TO EXCLUDE THE MENTION.
REALLY THE BRUNT OF THE COLDER AIR HOLDS OFF FROM MOVING INTO THE
CWA UNTIL LATER TODAY AND MAINLY THIS EVENING/TONIGHT. AS HAS BEEN
THE CASE OVER THE PAST FEW DAYS...MODELS CONTINUE TO SHOW THE
MAIN AXIS OF THE TROUGH...AND THUS THE COLDEST AIR...SETTING UP
JUST EAST OF THE CWA TONIGHT/THROUGH MONDAY. WHILE THE CWA MAY
CATCH A BRIEF BREAK FROM CLOUD COVER TONIGHT...EXPECTING TO SEE
ADDITIONAL CLOUD COVER /MAINLY UPPER LEVEL/ STREAMING IN FROM THE
NORTHWEST...KEEPING MAINLY THE NORTHEASTERN HALF OF THE CWA UNDER
PARTLY/MOSTLY CLOUDY SKIES ON MONDAY. DIDNT MAKE ANY NOTABLE
CHANGES TO MONDAYS HIGHS...WHICH RANGE FROM THE LOWER 20S IN THE
NORTHEAST TO LOWER 30S IN THE SOUTHWEST. SURFACE HIGH PRESSURE
SLIDING IN FROM THE NORTHWEST WILL BRING FAIRLY LIGHT WINDS FOR
MOST LOCATIONS.
MONDAY NIGHT THROUGH TUESDAY...THE MAIN UPPER LEVEL TROUGH/COLDEST
AIR ALREADY STARTS ITS EASTWARD SHIFT MONDAY NIGHT...WHICH WILL
BRING A REBOUND IN TEMPS FOR TUESDAY. THE POSSIBILITY OF GETTING
CLIPPED IN THE NORTH BY MORE FLURRIES OR LIGHT SNOW WILL BE
SOMETHING TO CONSIDER WITH UPCOMING MODEL RUNS. CURRENTLY AM
KEEPING THE MENTION OUT OF THE FORECAST...WITH MODELS SHOWING THE
COLDER TEMPS AND BETTER POTENTIAL /MAINLY MONDAY NIGHT INTO THE
FIRST HALF OF TUESDAY/...DRIVEN BY A STRONG UPPER LEVEL JET
STREAK NOSING IN FROM THE N/NW...REMAINING ONCE AGAIN JUST OUTSIDE
THE N/NE EDGE OF THE CWA. WITH THE WARMER AIR STARTING TO BUILD
BACK IN FROM THE WEST...HIGHS CURRENTLY RANGE FROM THE UPPER 20S
IN THE NORTHEAST TO LOWER 40S IN THE WEST...AND SOME MODELS
SUGGEST THE WEST SHOULD BE WARMER. OVERNIGHT LOWS EXPECTED TO
REBOUND FROM THE SINGLE DIGITS/TEENS MONDAY NIGHT TO THE
TEENS/NEAR 20 TUESDAY NIGHT.
LONG TERM...(WEDNESDAY THRU SATURDAY)
THE MAIN STORY: BONE DRY PATTERN CONTINUES WITH RE-AMPLIFYING NW
FLOW STUNTING TEMP RECOVERY...BUT SIGNALS CONTINUE FOR SOME PRECIP
POTENTIAL VERY LATE THIS MONTH.
PATTERN: THE HIGHLY AMPLIFIED WRN N AMERICA RIDGE/ERN TROF WILL
MEET ITS DEMISE NEXT WEEK AS A PACIFIC SHRTWV TROF MOVES ONSHORE
IN THE PAC NW WED AND MOVES THRU THE RIDGE. AS THIS TROF MOVES
INTO THE LGWV TROF THU-FRI...THE PATTERN WILL RE-AMPLIFY
SOMEWHAT...CURBING OUR WARM-UP FRI-SAT. RIDGING THEN ADVANCES OVER
THE PLAINS NEXT WEEKEND...FOLLOWED BY LOWERING HGTS OVER WRN N
AMERICA THE LAST WEEK OF JAN...SUGGESTING A PERIOD OF STORMINESS
AND PCPN POTENTIAL.
MODELS: THERE IS GOOD AGREEMENT AMONGST THE 00Z EC/GFS/GEM ON THIS
SCENARIO THRU 00Z/SAT. THE ONE CAVEAT...THE OPERATIONAL 18Z/00Z GFS
ARE NOT AS AMPLIFIED WITH THE TEMPORARILY REINVIGORATED RIDING OVER
WRN N AMERICA. IN FACT...THE GFS ENSEMBLE MEAN IS CLOSER TO THE
MORE AMPLIFIED 12Z/00Z EC CYCLES. THIS FCST INCORPORATES
EC/GFS/GEM/HPC GUIDANCE THRU 00Z/SAT. BEYOND THAT ITS HPC/EC AND
EC/GFS ENSEMBLE MEANS.
TEMPS: ESSENTIALLY NEAR NORMAL THRU SAT WITH ONE DAY OF BELOW
NORMAL FRI.
HAZARDS: NONE ENVISIONED ATTM.
UPCOMING PCPN OPPORTUNITIES: NOTHING NOTABLE THRU AT LEAST SAT AND
PROBABLY TO MON 1/28. HOWEVER...ODDS ARE INCREASING FOR A MDT
PCPN EVENT AS WE CLOSE THE BOOKS ON JAN.
THE DAILY DETAILS...
WED: M/SUNNY. PROBABLY NEAR NORMAL TEMPS. LEE TROF INTENSIFIES
WITH TROF MOVING INTO PAC NW...AIDING IN MODEST TEMP RECOVERY.
TEMP CONFIDENCE GRAPHICS SHOW ABOVE NORMAL SPREAD IN TEMPS.
THU: P/CLOUDY. A DRY COLD FRONTAL PASSAGE IN THE PRE-DAWN HRS. LOW
PRES EJECTS OUT OF CO ACROSS KS/OK. SOME DIFF/S IN TIMING REMAIN
WITH THE EC/GEM FASTER AND MORE POTENT THAN THE GFS. THE 00Z EC
ENSEMBLES HAVE COME INTO MUCH BETTER AGREEMENT ON SLP SINCE ITS
12Z RUN. HPC IS IN AGREEMENT SO WE/LL ROLL WITH THIS SCENARIO.
ABOVE NORMAL UNCERTAINTY IN TEMPS.
THU HAS POTENTIAL TO BE A BREEZY DAY. HOWEVER...SOME BAGGINESS IN
THE PRES TROF OF A REINFORCING SHOT OF COLD AIR COULD MITIGATE.
THU NGT: ANOTHER PUSH OF COLDER AIR MOVES THRU AS THE SHRTWV TROF
PASSES...BUT THE WORST OF IT REMAINS OFF TO THE N AND E.
FRI: P/CLOUDY. ARCTIC HIGH PRES EXPANDS OVER THE MS VALLEY. IF THE
EC IS RIGHT ANOTHER WEAK LOW MOVES THRU DELIVERING ANOTHER PUSH OF
MARGINALLY COLD AIR. CONFIDENCE IS ABOVE NORMAL ON A COOL DOWN.
TEMPS PROBABLY CLOSE TO 10F BELOW NORMAL.
SAT: SUNNY AS YET ANOTHER ARCTIC HIGH EXPANDS OVER THE MS VALLEY.
HGTS BEGIN RISING AS BROAD RIDGING ADVANCES TOWARD THE PLAINS. WAA
BEGINS WITH A NEW LEE TROF DEVELOPING.
BEYOND SAT...
A VERY NICE WARM-UP COMMENCES SUN THAT COULD LINGER INTO EARLY THE
FOLLOWING WEEK 1/28-29 DEPENDENT ON HOW THE PATTERN SHAPES UP.
WE COULD SEE 1 OR 2 DAYS OF MUCH ABOVE NORMAL TEMPS (+10F OR
MORE). IF WE ROLL WITH THE OPERATIONAL EC AND THE EC/GFS ENSEMBLES
LATE THIS WEEK...THEN WE MUST GO SLOWER THAN THE OPERATIONAL GFS
FOR EARLY THE FOLLOWING WEEK. THE GREATER AMPLIFIED SCENARIO WILL
SLOW THINGS DOWN UPSTREAM. EITHER WAY...THE NEXT PAC TROF WILL DIG
INTO THE DESERT SW THE LAST WEEK OF JAN. THIS IS A FAVORABLE SETUP
FOR A DECENT PCPN EVENT HERE AND WITH THE LOW TRACKING S OF THE
FCST AREA...THIS COULD END UP BEING THE WINTRY VARIETY. HOPEFULLY
WE/LL HAVE TIME TO ENTRAIN GOOD MSTR AFTER MULTIPLE EPISODES OF
CONTINENTAL POLAR AIR HAVE PLUNGED INTO THE GULF.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
KS...NONE.
&&
$$
AVIATION/UPDATE...PFANNKUCH
SHORT TERM...ADO
LONG TERM...HALBLAUB
AREA FORECAST DISCUSSION
NWS HASTINGS NE
1046 AM CST SUN JAN 20 2013
.UPDATE...FOR NOT HAVING HIGH IMPACT WEATHER...TODAY/S FORECAST
REMAINS CHALLENGING ESPECIALLY REGARDING TEMPERATURE TRENDS.
ALTHOUGH CONFIDENCE IN THE HOURLY DETAILS REMAINS SOMEWHAT BELOW
AVERAGE...THE OVERALL MESSAGE FROM VARIOUS MODEL/GUIDANCE SOURCES
SUCH AS HRRR...RAP AND GFS LAMP STRONGLY SUGGESTED THAT PREVIOUS
HIGHS WERE AT LEAST A BIT TOO WARM. AS A RESULT...TRIMMED AT LEAST
1-2 DEGREES OFF HIGHS FOR GENERALLY THE SOUTHWESTERN 2/3 OF THE
CWA...BUT MADE MORE SIGNIFICANT 5-7 DEGREE CUTS TO ESPECIALLY THE
NORTHEAST 1/4 OF OUR AREA...OR ESPECIALLY NORTHEAST OF AN ORD-YORK
LINE. IN THESE NORTHEAST AREAS...TEMPS WILL BE LUCKY TO REACH THE
MID-UPPER 20S...WHILE AT LEAST LOW-MID 30S STILL LOOK POSSIBLE
ACROSS MOST OF THE REMAINDER OF OUR NEB ZONES. KS ZONES COULD
STILL MAKE A RUN AT THE LOW 40S...ALTHOUGH EVEN HERE MAY CONSIDER
LOWERING A BIT IN A FUTURE UPDATE. OTHERWISE...A GENERALLY LIGHT
AND VARIABLE WIND REGIME WILL REMAIN IN PLACE ALL AREAS UNTIL AT
LEAST EARLY AFTERNOON...BUT THEREAFTER A GRADUAL INCREASE IN
NORTHERLY SPEEDS WILL START OVERTAKING THE CWA FROM WEST TO
EAST...WITH AT LEAST A SHORT PERIOD OF 20+ MPH GUSTS EXPECTED TO
AFFECT MOST ALL AREAS BY MID-LATE AFTERNOON. PRECIP-WISE...WILL
CONTINUE TO LEAVE FLURRIES OUT OF THIS AFTERNOON/S FORECAST FOR
OUR FAR NORTHEAST COUNTIES...AS RADAR TRENDS AND SHORT TERM MODELS
CONTINUE TO SUGGEST THAT ANY SUCH ACTIVITY SHOULD LARGELY SLIDE BY
JUST TO OUR NORTHEAST.
&&
.PREV DISCUSSION... /ISSUED 603 AM CST SUN JAN 20 2013/
AVIATION.../12Z GRI TAF THROUGH 12Z MONDAY MORNING/
EARLY THIS MRNG: VFR WITH MULTIPLE LAYERS OF MID-HIGH CIGS ABOVE
15K FT. HOWEVER...SATELLITE AND SFC OBS INDICATE IFR/LOW-END MVFR
STRATUS DEVELOPING ALONG A FRONT 100 SM W OF GRI. HAVE INDICATED
SCT015 BEGINNING AT 12Z TO ACCOUNT FOR WHAT WE BELIEVE WILL BE AN
EVENTUAL DECAY TO MVFR CIGS.
TODAY: WITH THE ON-GOING DEVELOPMENT OF STRATUS...CONFIDENCE HAS
INCREASED IN MVFR CIGS AND LATEST FCST SOUNDINGS ARE SUPPORTIVE.
SO MVFR CIGS ARE NOW IN THE TAF. THERE IS A LOW PROB FOR A PERIOD
OF IFR CIGS. WINDS WILL REMAIN LIGHT AND VARIABLE UNTIL ARCTIC
FROPA...WITHIN AN HOUR OR TWO OF 19Z. AFTER FROPA...EXPECT A WSHFT
TO N WITH GUSTS UP TO 20 KTS. THERE IS ALSO POTENTIAL FOR CIGS TO
IMPROVE TO 3500 FT.
TNGT: FCST SOUNDINGS CONTINUE TO INDICATE POTENTIAL FOR MVFR CIGS.
NOT ALL FCST GUIDANCE AGREES WHICH LOWERS CONFIDENCE. SOME
GUSTINESS CONTINUES INTO THE EVNG...THEN NNW WINDS SHOULD SETTLE
AROUND 8 KTS.
CIG CONFIDENCE: AVERAGE
VSBY CONFIDENCE: HIGH
WIND CONFIDENCE: AVERAGE. EXACT TIME OF FROPA UNCERTAIN. ALSO
UNSURE OF DEGREE OF GUSTINESS POST-FROPA.
WX CONFIDENCE: HIGH
PREV DISCUSSION... /ISSUED 414 AM CST SUN JAN 20 2013/
SHORT TERM...TODAY THROUGH TUESDAY NIGHT. PRIMARY FORECAST
CONCERN LIES WITH TEMPERATURES.
QUIET CONDITIONS REMAIN IN PLACE ACROSS THE REGION EARLY THIS
MORNING...WITH SATELLITE AND UPPER AIR PROFILER DATA SHOWING
NORTHWESTERLY FLOW IN PLACE. RIDGING CONTINUES ALONG THE WEST
COAST...WHILE A COUPLE OF DISTURBANCES WORK THEIR WAY THROUGH THE
NWRLY FLOW...ONE OVER THE GREAT LAKES REGION AND THE OTHER OVER SC
CANADA. AT THE SURFACE...HIGH PRESSURE CONTINUES TO SLIDE SOUTH
OUT OF THE DAKOTAS INTO THE AREA...BEHIND A COLD FRONT WHICH
PASSED THROUGH THE REGION LATE SAT AFTN/EVENING. WITH TIME...WINDS
HAVE GRADUALLY BECOME MORE EASTERLY ACROSS THE CWA...AND HAVE
DIMINISHED IN SPEED.
LOOKING AT THE REST OF TODAY AND INTO MONDAY...THE MAIN STORY LIES
WITH THE PASSAGE OF YET ANOTHER COLD FRONT...AND ITS AFFECT ON
TEMPERATURES. MODELS REMAIN IN GOOD AGREEMENT SHOWING THE ABOVE
MENTIONED UPPER LEVEL DISTURBANCE OVER SC CANADA CONTINUING TO
SLIDE SOUTHEAST THROUGH THE DAY TODAY...WITH THE TIMING OF THE
ACCOMPANYING SFC COLD FRONT/NORTHWESTERLY WINDS STILL EXPECTED TO
PASS THROUGH THE CWA DURING THE AFTERNOON HOURS. THE TIMING MAKES
TEMPERATURES TODAY PRETTY DIFFICULT...ESP WITH MODELS/GUIDANCE NOT
IN VERY GOOD AGREEMENT...MAINLY FOR THOSE NORTHWESTERN PORTIONS OF
THE CWA...WHICH WILL PROB SEE THEIR HIGHS CLOSER TO MIDDAY/EARLY
AFTN VS MID AFTN FURTHER SOUTH. OVERALL DIDNT MAKE MANY CHANGES TO
THE INHERITED FORECAST...WHICH CONTINUES TO CALL FOR GENERALLY MID
30S ACROSS SC NEB...WITH LOWER 40S IN NC KS. CERTAINLY SOMETHING
FOR THE DAYSHIFT TO KEEP AN EYE ON.
AS FAR AS THE POSSIBILITY OF FLURRIES GOES...DECIDED TO KEEP THE
MENTION OUT OF THE FORECAST. AS THAT DISTURBANCE SWINGS SOUTH...IT
WILL BRING ALONG MORE CLOUD COVER AND COLDER TEMPERATURES...AND
WHILE MODELS DO SHOW SOME BATCHES OF INCREASED LOWER LEVEL /BELOW
700MB/ MOISTURE MOVING INTO THE REGION...MAINLY THIS
AFTERNOON...THERE IS ALSO PRETTY GOOD AGREEMENT WITH KEEPING THE
BETTER RH AND COLDER TEMPS MORE FAVORABLE FOR FLURRIES
NORTH/NORTHEAST OF THE CWA...BARELY. THE OPER NAM/GFS/EC CONTINUE
TO SHOW THE CWA DRY...AS DOES THE HRRR. THE RAP AND ONE RUN OF THE
4 KM SHOW PERHAPS THE FAR N/NE EDGE OF THE CWA MAYBE SEEING A
FEW...BUT AM GOING TO CONTINUE TO EXCLUDE THE MENTION.
REALLY THE BRUNT OF THE COLDER AIR HOLDS OFF FROM MOVING INTO THE
CWA UNTIL LATER TODAY AND MAINLY THIS EVENING/TONIGHT. AS HAS BEEN
THE CASE OVER THE PAST FEW DAYS...MODELS CONTINUE TO SHOW THE
MAIN AXIS OF THE TROUGH...AND THUS THE COLDEST AIR...SETTING UP
JUST EAST OF THE CWA TONIGHT/THROUGH MONDAY. WHILE THE CWA MAY
CATCH A BRIEF BREAK FROM CLOUD COVER TONIGHT...EXPECTING TO SEE
ADDITIONAL CLOUD COVER /MAINLY UPPER LEVEL/ STREAMING IN FROM THE
NORTHWEST...KEEPING MAINLY THE NORTHEASTERN HALF OF THE CWA UNDER
PARTLY/MOSTLY CLOUDY SKIES ON MONDAY. DIDNT MAKE ANY NOTABLE
CHANGES TO MONDAYS HIGHS...WHICH RANGE FROM THE LOWER 20S IN THE
NORTHEAST TO LOWER 30S IN THE SOUTHWEST. SURFACE HIGH PRESSURE
SLIDING IN FROM THE NORTHWEST WILL BRING FAIRLY LIGHT WINDS FOR
MOST LOCATIONS.
MONDAY NIGHT THROUGH TUESDAY...THE MAIN UPPER LEVEL TROUGH/COLDEST
AIR ALREADY STARTS ITS EASTWARD SHIFT MONDAY NIGHT...WHICH WILL
BRING A REBOUND IN TEMPS FOR TUESDAY. THE POSSIBILITY OF GETTING
CLIPPED IN THE NORTH BY MORE FLURRIES OR LIGHT SNOW WILL BE
SOMETHING TO CONSIDER WITH UPCOMING MODEL RUNS. CURRENTLY AM
KEEPING THE MENTION OUT OF THE FORECAST...WITH MODELS SHOWING THE
COLDER TEMPS AND BETTER POTENTIAL /MAINLY MONDAY NIGHT INTO THE
FIRST HALF OF TUESDAY/...DRIVEN BY A STRONG UPPER LEVEL JET
STREAK NOSING IN FROM THE N/NW...REMAINING ONCE AGAIN JUST OUTSIDE
THE N/NE EDGE OF THE CWA. WITH THE WARMER AIR STARTING TO BUILD
BACK IN FROM THE WEST...HIGHS CURRENTLY RANGE FROM THE UPPER 20S
IN THE NORTHEAST TO LOWER 40S IN THE WEST...AND SOME MODELS
SUGGEST THE WEST SHOULD BE WARMER. OVERNIGHT LOWS EXPECTED TO
REBOUND FROM THE SINGLE DIGITS/TEENS MONDAY NIGHT TO THE
TEENS/NEAR 20 TUESDAY NIGHT.
LONG TERM...(WEDNESDAY THRU SATURDAY)
THE MAIN STORY: BONE DRY PATTERN CONTINUES WITH RE-AMPLIFYING NW
FLOW STUNTING TEMP RECOVERY...BUT SIGNALS CONTINUE FOR SOME PRECIP
POTENTIAL VERY LATE THIS MONTH.
PATTERN: THE HIGHLY AMPLIFIED WRN N AMERICA RIDGE/ERN TROF WILL
MEET ITS DEMISE NEXT WEEK AS A PACIFIC SHRTWV TROF MOVES ONSHORE
IN THE PAC NW WED AND MOVES THRU THE RIDGE. AS THIS TROF MOVES
INTO THE LGWV TROF THU-FRI...THE PATTERN WILL RE-AMPLIFY
SOMEWHAT...CURBING OUR WARM-UP FRI-SAT. RIDGING THEN ADVANCES OVER
THE PLAINS NEXT WEEKEND...FOLLOWED BY LOWERING HGTS OVER WRN N
AMERICA THE LAST WEEK OF JAN...SUGGESTING A PERIOD OF STORMINESS
AND PCPN POTENTIAL.
MODELS: THERE IS GOOD AGREEMENT AMONGST THE 00Z EC/GFS/GEM ON THIS
SCENARIO THRU 00Z/SAT. THE ONE CAVEAT...THE OPERATIONAL 18Z/00Z GFS
ARE NOT AS AMPLIFIED WITH THE TEMPORARILY REINVIGORATED RIDING OVER
WRN N AMERICA. IN FACT...THE GFS ENSEMBLE MEAN IS CLOSER TO THE
MORE AMPLIFIED 12Z/00Z EC CYCLES. THIS FCST INCORPORATES
EC/GFS/GEM/HPC GUIDANCE THRU 00Z/SAT. BEYOND THAT ITS HPC/EC AND
EC/GFS ENSEMBLE MEANS.
TEMPS: ESSENTIALLY NEAR NORMAL THRU SAT WITH ONE DAY OF BELOW
NORMAL FRI.
HAZARDS: NONE ENVISIONED ATTM.
UPCOMING PCPN OPPORTUNITIES: NOTHING NOTABLE THRU AT LEAST SAT AND
PROBABLY TO MON 1/28. HOWEVER...ODDS ARE INCREASING FOR A MDT
PCPN EVENT AS WE CLOSE THE BOOKS ON JAN.
THE DAILY DETAILS...
WED: M/SUNNY. PROBABLY NEAR NORMAL TEMPS. LEE TROF INTENSIFIES
WITH TROF MOVING INTO PAC NW...AIDING IN MODEST TEMP RECOVERY.
TEMP CONFIDENCE GRAPHICS SHOW ABOVE NORMAL SPREAD IN TEMPS.
THU: P/CLOUDY. A DRY COLD FRONTAL PASSAGE IN THE PRE-DAWN HRS. LOW
PRES EJECTS OUT OF CO ACROSS KS/OK. SOME DIFF/S IN TIMING REMAIN
WITH THE EC/GEM FASTER AND MORE POTENT THAN THE GFS. THE 00Z EC
ENSEMBLES HAVE COME INTO MUCH BETTER AGREEMENT ON SLP SINCE ITS
12Z RUN. HPC IS IN AGREEMENT SO WE/LL ROLL WITH THIS SCENARIO.
ABOVE NORMAL UNCERTAINTY IN TEMPS.
THU HAS POTENTIAL TO BE A BREEZY DAY. HOWEVER...SOME BAGGINESS IN
THE PRES TROF OF A REINFORCING SHOT OF COLD AIR COULD MITIGATE.
THU NGT: ANOTHER PUSH OF COLDER AIR MOVES THRU AS THE SHRTWV TROF
PASSES...BUT THE WORST OF IT REMAINS OFF TO THE N AND E.
FRI: P/CLOUDY. ARCTIC HIGH PRES EXPANDS OVER THE MS VALLEY. IF THE
EC IS RIGHT ANOTHER WEAK LOW MOVES THRU DELIVERING ANOTHER PUSH OF
MARGINALLY COLD AIR. CONFIDENCE IS ABOVE NORMAL ON A COOL DOWN.
TEMPS PROBABLY CLOSE TO 10F BELOW NORMAL.
SAT: SUNNY AS YET ANOTHER ARCTIC HIGH EXPANDS OVER THE MS VALLEY.
HGTS BEGIN RISING AS BROAD RIDGING ADVANCES TOWARD THE PLAINS. WAA
BEGINS WITH A NEW LEE TROF DEVELOPING.
BEYOND SAT...
A VERY NICE WARM-UP COMMENCES SUN THAT COULD LINGER INTO EARLY THE
FOLLOWING WEEK 1/28-29 DEPENDENT ON HOW THE PATTERN SHAPES UP.
WE COULD SEE 1 OR 2 DAYS OF MUCH ABOVE NORMAL TEMPS (+10F OR
MORE). IF WE ROLL WITH THE OPERATIONAL EC AND THE EC/GFS ENSEMBLES
LATE THIS WEEK...THEN WE MUST GO SLOWER THAN THE OPERATIONAL GFS
FOR EARLY THE FOLLOWING WEEK. THE GREATER AMPLIFIED SCENARIO WILL
SLOW THINGS DOWN UPSTREAM. EITHER WAY...THE NEXT PAC TROF WILL DIG
INTO THE DESERT SW THE LAST WEEK OF JAN. THIS IS A FAVORABLE SETUP
FOR A DECENT PCPN EVENT HERE AND WITH THE LOW TRACKING S OF THE
FCST AREA...THIS COULD END UP BEING THE WINTRY VARIETY. HOPEFULLY
WE/LL HAVE TIME TO ENTRAIN GOOD MSTR AFTER MULTIPLE EPISODES OF
CONTINENTAL POLAR AIR HAVE PLUNGED INTO THE GULF.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
KS...NONE.
&&
$$
UPDATE...PFANNKUCH
SHORT TERM...ADO
LONG TERM/AVIATION...HALBLAUB
AREA FORECAST DISCUSSION
NWS AMARILLO TX
310 PM CST SUN JAN 20 2013
.DISCUSSION...
THROUGH TONIGHT: MAIN CONCERN TONIGHT REVOLVES AROUND POTENTIAL
DEVELOPMENT OF FREEZING FOG VS. LOW STRATUS. A DRY COLD FRONT
LOCATED ALONG THE CANADIAN RIVER VALLEY IS TRUCKING SOUTHWARD THIS
AFTERNOON. STRONG NORTHERLY WINDS HAVE DEVELOPED BEHIND THE FRONT
WITH A FEW GUSTS UP TO 35 MPH. THIS NORTHERLY SURGE OF GUSTY WINDS
WILL CONTINUE TO PUSH SOUTHWARD THROUGH THE AFTERNOON AND EVENING
HOURS, BUT IT SHOULD DIMINISH IN INTENSITY NEAR SUNSET. LOW-LEVEL
MOISTURE IS EXPECTED TO POOL BEHIND THE FRONT TONIGHT, BUT MODEL
GUIDANCE SHOWS VARYING DEGREES OF MOISTURE CONTENT. THE LATEST RUC
AND HRRR HAVE BACKED OFF ON THE POTENTIAL FOR WIDESPREAD FREEZING
FOG, BUT THE GFS AND NAM CONTINUE TO INDICATE THIS POTENTIAL. GIVEN
THE SYNOPTIC PATTERN, THIS SETUP IS LOCALLY FAVORABLE FOR SOME
PATCHY (FREEZING) FOG, SO WE LEFT THIS IN THE FORECAST. WE EXPECT
FREEZING FOG TO DEVELOP BETWEEN 3 AM ACROSS THE EASTERN PANHANDLES
AND SPREAD WESTWARD. OTHER MODEL GUIDANCE, INCLUDING THE TEXAS TECH
WRF, INDICATES THAT LOW STRATUS WILL BE MORE FAVORED THAN FOG. DUE
TO THESE UNCERTAINTIES, WE INCLUDED BOTH INCREASING CLOUDS AND PATCHY
FREEZING FOG IN THE FORECAST, BUT OUR FORECAST CONFIDENCE IS LOW.
OVERNIGHT LOW TEMPERATURES WILL RANGE FROM THE UPPER TEENS TO UPPER
20S. THE POTENTIAL FOR FREEZING DRIZZLE THAT WE DISCUSSED YESTERDAY
HAS DIMINISHED AS THE DEPTH OF THE MOIST LAYER WILL BE LESS THAN
2000 FEET.
MARTIN LUTHER KING, JR. DAY-NIGHT: ANY FREEZING FOG THAT DEVELOPS
OVERNIGHT SHOULD DISSIPATE BY 10 AM. LOW CLOUDS, IF THEY DEVELOP,
COULD HANG TOUGH INTO THE EARLY AFTERNOON HOURS, ESPECIALLY ACROSS
THE SOUTHEASTERN TEXAS PANHANDLE. SURFACE WINDS WILL QUICKLY SHIFT TO
THE SOUTH BY THE AFTERNOON HOURS, BUT HIGH TEMPERATURES WILL BE ABOUT
10-15 DEGREES COLDER THAN TODAY DUE TO THE MODIFIED ARCTIC AIR MASS.
TUESDAY-SUNDAY: A BACKDOOR COLD FRONT WILL SNEAK INTO THE
NORTHEASTERN HALF OF THE FORECAST AREA TUESDAY MORNING AND MAY BE
SLOW TO RETREAT NORTHWARD. THIS SHOULD KEEP AN UPSLOPE COMPONENT TO
THE WINDS FOR MUCH OF THE DAY. AS A RESULT, WE COOLED HIGHS OFF
SEVERAL DEGREES, AND THERE IS A POSSIBILITY WE MAY STILL BE TOO WARM.
THIS FRONT WILL LIFT OUT OF THE FORECAST AREA ON WEDNESDAY AS UPPER
RIDGING BUILDS ACROSS THE AREA. HIGHS ON WEDNESDAY ARE EXPECTED TO
WARM INTO THE LOWER 60S TO POSSIBLY NEAR 70. AN UPPER TROUGH MOVING
INTO NORTHERN PLAINS ON THURSDAY WILL SWING ANOTHER DRY COLD FRONT
SOUTHWARD. WE SPED UP THE TIMING OF THE FRONT GIVEN THAT IT WILL ALSO
BE A STRONG FRONT. AS A RESULT, HIGHS FOR THURSDAY HAVE BEEN TRIMMED
DOWNWARD AND WIND SPEEDS INCREASED, ESPECIALLY BEHIND THE FRONT.
COOLER TEMPERATURES WILL RETURN FOR FRIDAY, BUT A WARMING TREND WILL
RESUME FOR NEXT WEEKEND.
JACKSON
&&
.FIRE WEATHER...
NO ELEVATED OR CRITICAL FIRE WEATHER CONDITIONS ARE ANTICIPATED
MONDAY THROUGH WEDNESDAY AS RELATIVE HUMIDITY VALUES WILL REMAIN
ABOVE 20 PERCENT AND/OR 20-FOOT WINDS WILL REMAIN BELOW 15 MPH.
ELEVATED FIRE WEATHER CONDITIONS WILL BE POSSIBLE ACROSS THE WESTERN
TWO THIRDS OF THE PANHANDLES ON THURSDAY AS DRY NORTHERLY WINDS
INCREASE. ELEVATED FIRE WEATHER CONDITIONS WILL ALSO BE POSSIBLE
ACROSS THE FAR WESTERN PANHANDLES ON SATURDAY.
&&
.PRELIMINARY POINT TEMPS/POPS...
AMARILLO TX 23 50 28 58 30 / 0 0 0 0 0
BEAVER OK 19 47 23 51 24 / 0 0 0 0 0
BOISE CITY OK 18 51 25 58 26 / 0 0 0 0 0
BORGER TX 24 50 29 57 32 / 0 0 0 0 0
BOYS RANCH TX 24 50 27 59 28 / 0 0 0 0 0
CANYON TX 25 50 27 59 27 / 0 0 0 0 0
CLARENDON TX 26 48 30 58 34 / 0 0 0 0 0
DALHART TX 19 49 23 58 24 / 0 0 0 0 0
GUYMON OK 19 51 24 56 26 / 0 0 0 0 0
HEREFORD TX 26 50 25 60 28 / 0 0 0 0 0
LIPSCOMB TX 21 48 22 52 26 / 0 0 0 0 0
PAMPA TX 22 48 29 57 31 / 0 0 0 0 0
SHAMROCK TX 25 48 26 56 30 / 0 0 0 0 0
WELLINGTON TX 27 47 27 57 32 / 0 0 0 0 0
&&
.AMA WATCHES/WARNINGS/ADVISORIES...
TX...NONE.
OK...NONE.
&&
$$
EA/JJ
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
250 PM CST SUN JAN 20 2013
.SHORT TERM...TONIGHT THROUGH WEDNESDAY
250 PM CST SUN JAN 20 2013
MAIN FORECAST CONCERNS ARE ON TEMPERATURES/WIND CHILLS THROUGH
TUESDAY AND ANY POTENTIAL LIGHT PRECIPITATION THROUGHOUT THE SHORT
TERM.
CURRENTLY AS OF 20Z...WATER VAPOR LOOP AND RAP 500MB HEIGHT ANALYSIS
SHOWED RIDGING ALONG THE U.S. WEST COAST INTO WESTERN BRITISH
COLUMBIA...WHILE DEEP TROUGHING ENCOMPASSED THE EASTERN TWO-THIRDS
OF CANADA INTO THE UPPER MISSISSIPPI RIVER VALLEY AND GREAT LAKES
REGIONS. 500MB HEIGHTS AS WELL AS 850MB TEMPS WERE 1-1.5 STANDARD
DEVIATIONS BELOW NORMAL OVER THE FORECAST AREA. REGARDING THE 850MB
TEMPS...RAP ANALYSIS SHOWED READINGS OF -16 TO -20C OVER THE
FORECAST AREA. WITHIN THE DEEP TROUGHING...A SHORTWAVE WAS EVIDENT
FROM EASTERN SOUTH DAKOTA INTO NORTHERN IOWA. DPVA ASSOCIATED WITH
THE SHORTWAVE...MID-LEVEL MOISTURE SEEN ON THE 12Z ABR SOUNDING...AS
WELL AS LOW TO MID LEVEL FRONTOGENESIS WAS SUPPORTING AN AREA OF
LIGHT SNOW JUST SOUTH OF THE SHORTWAVE ACROSS WESTERN AND CENTRAL
IOWA. ONLY SOME SCATTERED ALTOSTRATUS HAS OVERSPREAD THE FORECAST
AREA ASSOCIATED WITH THE SHORTWAVE. SUNSHINE THROUGH THESE CLOUDS
AND THE COLD 850MB TEMPS HAS ONLY ALLOWED TEMPERATURES TO CLIMB INTO
THE LOWER TO MID TEENS. ON THE WEST SIDE OF THE DEEP TROUGH...A
120-140 KT JET AT THE TROPOPAUSE WAS DROPPING DOWN THROUGH EASTERN
ALBERTA AND SASKATCHEWAN. THE STRENGTH OF THIS JET IS PARTLY DUE TO
ANOTHER SURGE OF ARCTIC AIR...WITH THE RAP SHOWING 850MB TEMPS OF
-25 TO -30C FROM NORTH DAKOTA INTO MANITOBA. THIS COLD AIR WAS ALSO
SITTING RIGHT BEHIND A COLD FRONT STRETCHING FROM NEAR ABERDEEN
SOUTH DAKOTA INTO THE MN ARROWHEAD.
TONIGHT AND MONDAY...THE 120-140 KT JET STREAK OVER EASTERN ALBERTA
INTO SASKATCHEWAN IS PROGGED TO DIG INTO THE DAKOTAS TONIGHT AND INTO
IOWA ON MONDAY. THE FORECAST AREA ENDS UP IN THE LEFT EXIT REGION OF
THIS JET MONDAY MORNING...WHILE THE TROPOPAUSE DROPS TO AROUND
375MB. THESE STRENGTHENING UPPER DYNAMICS WILL END UP TIGHTENING THE
SURFACE PRESSURE GRADIENT OVER THE FORECAST AREA TONIGHT...HELPING
TO BRING IN THAT VERY COLD 850MB AIR ACROSS NORTH DAKOTA. NOT
ANTICIPATING ANY PRECIPITATION FROM THE DYNAMICAL FORCING...
PRIMARILY BECAUSE THERE IS TOO MUCH MID-LEVEL DRY AIR ACCOMPANYING
THE COLD ADVECTION AS SHOWN ON FORECAST SOUNDINGS. IN ADDITION...
THERE ARE CLEAR SKIES CURRENTLY PRESENT OVER NORTHWEST NORTH DAKOTA
AND SOUTH CENTRAL CANADA IN THE LEFT EXIT REGION. ONLY PRECIPITATION
THAT MAY OCCUR WOULD BE LIMITED TO FLURRIES...ASSOCIATED WITH THE
LOW CLOUDS AHEAD OF THAT COLD FRONT DROPPING SOUTHEAST OUT OF
NORTHERN SOUTH DAKOTA INTO THE MN ARROWHEAD. ADDITIONAL FLURRIES
COULD OCCUR ON MONDAY NORTH OF I-94...ASSOCIATED WITH LOW TO MID
LEVEL MOISTURE MOVING THROUGH WHICH IS CURRENTLY IN NORTHERN
MANITOBA. REGARDING TEMPERATURES...THEY ARE TRICKY GIVEN THE LACK OF
SNOW COVER AND THE INCREASING WINDS PROMOTING MIXING. WE DEFINITELY
ARE NOT GOING TO GET AS COLD AS THE DAKOTAS AND NORTHERN MN WHERE
SNOW EXISTS. STILL...ADVECTION ALONE AND CLEARING SKIES...COMBINED
WITH THE FACT THAT THE INCOMING 850MB TEMPS ARE 2-2.5 STANDARD
DEVIATIONS BELOW NORMAL...SHOULD ALLOW TEMPERATURES IN MOST
LOCATIONS TO DROP BELOW ZERO. SOME LOCATIONS OVER NORTH CENTRAL
WISCONSIN AND SOUTHEAST MN COULD EVEN DROP TO 10 BELOW ZERO OR SO.
TEMPERATURES WILL STRUGGLE TO RECOVER ON MONDAY BEING UNDER THE
850MB THERMAL TROUGH...BUT SUN AND BARE GROUND SHOULD GET HIGHS TO
NEAR OR SLIGHTLY ABOVE ZERO PER THE ECMWF. THE ECMWF HAS DONE WELL
HANDLING HIGH TEMPERATURES WITH THE BARE GROUND AND THUS WAS THE
PREFERRED GUIDANCE. WIND CHILLS WILL SOLIDLY END UP IN THE WIND
CHILL ADVISORY RANGE FROM LATE TONIGHT INTO MUCH OF MONDAY... AND
MAY EVEN APPROACH WARNING MONDAY MORNING OVER PORTIONS OF SOUTHEAST
MN. CONFIDENCE IS STILL NOT HIGH ENOUGH TO GO WITH THE WARNING GIVEN
UNCERTAINTY ON LOW TEMPERATURES.
MONDAY NIGHT AND TUESDAY...THE DEEP UPPER TROUGH IS PROGGED TO SHIFT
SLIGHTLY EASTWARD DURING THIS PERIOD AS THE RIDGE ALONG THE U.S.
WEST COAST GETS A PUSH EAST. IN RESPONSE...THE ARCTIC HIGH PRESSURE
AREA CURRENTLY SITTING UP IN ALBERTA IS ALLOWED TO BUILD INTO THE
FORECAST AREA. MODELS ARE IN GOOD AGREEMENT OF THE HIGH PRESSURE
AREA ENCOMPASSING THE AREA AT 00Z WEDNESDAY. UNTIL THE HIGH BUILDS
IN...A SLOWLY WEAKENING PRESSURE GRADIENT WILL EXIST...MAINTAINING A
NORTHWESTERLY BREEZE AND KEEPING WIND CHILLS DOWN. THUS...HAVING THE
WIND CHILL ADVISORY GO TO 18Z TUESDAY STILL LOOKS GOOD. SKIES SHOULD
END UP CLEAR IN MOST AREAS BY 12Z TUESDAY...FAVORING GOOD
RADIATIONAL COOLING. AGAIN...THE LACK OF SNOW COVER AND BREEZE WILL
ACT AGAINST GETTING TOO COLD. GIVEN THE COLDER MONDAY COMPARED TO
TODAY...SHOULD SEE LOWS AT LEAST A FEW DEGREES COLDER...ESPECIALLY
OVER THE SNOWPACK NORTH OF HIGHWAY 10. 850MB AND 925MB TEMPERATURES
ARE PROGGED TO ONLY SLOWLY RECOVER...CLIMBING TO -18 TO -22C AND -16
TO -22C RESPECTIVELY BY 00Z. DESPITE PLENTY OF SUNSHINE MINUS SOME
INCREASING HIGH CLOUDS IN THE AFTERNOON...ONLY ANTICIPATING HIGHS 5
TO 10 DEGREES WARMER PER ECMWF.
TUESDAY NIGHT AND WEDNESDAY...MODELS PROG A POTENT SHORTWAVE TO DROP
SOUTH OUT OF NORTHERN MANITOBA LATE TUESDAY AND HAVE IT CROSS LAKE
SUPERIOR LATE WEDNESDAY. MEANWHILE...THE WESTERN UPPER RIDGE BREAKS
DOWN AND FLATTENS WHILE SPREADING EAST...IN RESPONSE TO A POTENT
SHORTWAVE TROUGH CROSSING THE PACIFIC NORTHWEST. THE RESULT OF ALL
THIS IS TO STRENGTHEN THE UPPER JET CORE AT THE TROPOPAUSE OVER OR
JUST NORTH OF THE FORECAST AREA...TOWARDS 150-170 KT. WITH THE
STRENGTHENING UPPER JET COMES AN ISENTROPIC LIFT AND LOW TO MID
LEVEL FRONTOGENESIS ZONE ON ITS SOUTHWEST SIDE. THIS RESULTS IN
INCREASING AND THICKENING MID AND HIGH CLOUDS OVER THE FORECAST
AREA. FORCING IS NOT ALL THAT STRONG PER MODEL DERIVED OMEGA
FIELDS...BUT THE LOW LEVELS DO SLOWLY SATURATE OVER TIME. THUS...
THINK FLURRIES AT A MINIMUM WILL OCCUR. 20.12Z NAM ACTUALLY PRODUCES
SOME LIGHT QPF...ALBEIT IS THE MOST DYNAMIC BY EVEN HAVING A SURFACE
LOW DROPPING THROUGH IOWA. FOR NOW JUST WENT WITH ADDING
FLURRIES...BUT SOME CHANCES OF PRECIPITATION MAY NEED TO BE ADDED IF
MODELS TREND TOWARDS THE NAM. WITH THE THICKENING CLOUD COVER
AND BARE GROUND...TEMPERATURES SHOULD NOT FALL ALL THAT MUCH TUESDAY
NIGHT. 925MB TEMPS WARM FURTHER ON WEDNESDAY WITH THE UPPER FLOW
TURNING MORE WEST-NORTHWESTERLY...CLIMBING TO -8C SOUTHWEST TO -16C
NORTHEAST BY 00Z. THUS...DESPITE CLOUD COVER...TEMPERATURES SHOULD
BE ABLE TO CLIMB INTO THE MID TEENS TO MID 20S.
.LONG TERM...WEDNESDAY NIGHT THROUGH SUNDAY
250 PM CST SUN JAN 20 2013
VERY GOOD AGREEMENT EXISTS ON THE LONG TERM PATTERN FROM THE 20.12Z
ECMWF/GFS/CANADIAN AND ECMWF ENSEMBLES. THE SHORTWAVE TROUGH OVER
THE PACIFIC NORTHWEST TO START THE PERIOD DIGS INTO NEBRASKA AND
IOWA FOR THURSDAY. AN INVERTED TROUGH ACCOMPANIES THE SHORTWAVE...
WITH A COMBINATION OF MID-LEVEL FRONTOGENESIS...DPVA AND MOISTURE
EXPECTING TO BRING SOME SNOW ACROSS THE FORECAST AREA. HOWEVER...
THIS HAS BEEN A POINT OF CONTENTION FOR A FEW DAYS...WITH MODELS
VARYING ON HOW MUCH QPF WITH EVEN A FEW SUGGESTING DRY EITHER ON
THURSDAY AND/OR THURSDAY NIGHT. AS SUCH...HAVE KEPT A CONSENSUS
AROUND 30 PERCENT CHANCE FOR BOTH THURSDAY AND THURSDAY NIGHT.
CERTAINLY IF THE TREND IN THE 20.12Z ECMWF CONTINUES...WE WILL NEED
HIGHER CHANCES AS IT NOW SUGGESTS UPWARDS OF 2-3 INCHES OF SNOW.
THIS IS QUITE A BIT DIFFERENT FROM ITS PREVIOUS RUN...THOUGH.
ANOTHER SURGE OF CANADIAN AIR WITH HIGH PRESSURE IS STILL FORECAST
TO DROP INTO THE FORECAST AREA IN THE WAKE OF THIS SYSTEM FOR FRIDAY
AND FRIDAY NIGHT. HOWEVER...THE 850MB TEMPS ARE NOT NEARLY AS COLD
AS THE CURRENT ARCTIC AIR SURGE...ONLY PROGGED TO DIP DOWN TO -20C
AT MOST.
FOR THE WEEKEND...A DEEP TROUGH IS FORECAST TO FORM JUST OFF OR ON
THE WEST COAST OF THE U.S....SETTING UP A PATTERN CHANGE AS 500MB
HEIGHTS RISE DOWNSTREAM ACROSS THE REST OF THE U.S.. EVENTUALLY A
LOW PRESSURE SYSTEM FORMS IN THE VICINITY OF WYOMING AND COLORADO BY
LATE SUNDAY...BUT MOISTURE RETURN TOWARDS THE FORECAST AREA IS STILL
LIMITED. THUS...A DRY WEEKEND WITH WARMING TEMPERATURES IS IN STORE.
HOW WARM WILL DEPEND ON HOW MUCH SNOW OCCURS WITH THE THURSDAY
SYSTEM. FOLLOWED THE CONSENSUS FOR HIGH TEMPERATURES FOR THE
WEEKEND...BUT THESE MAY STILL BE TOO COOL GIVEN 925MB TEMPS
CLIMBING TO 0 TO -4C BY 18Z SUNDAY PER 20.12Z GFS/ECMWF.
&&
.AVIATION...THIS AFTERNOON THROUGH MONDAY
1131 AM CST SUN JAN 20 2013
WEAK SHORTWAVE AND FORCING/LIFT WERE PASSING SOUTH/WEST OF THE AREA
LATE THIS MORNING...WITH DRIER LOW/MID LEVEL AIR HOLDING OVER THE
TAF SITES. AFTERNOON LOOKING FLURRY-FREE WITH SCT TO LCL BKN CLOUDS
AROUND 10K FT.
AREA OF LOWER BKN-OVC POST-TROUGH CLOUDS OVER NORTHERN MN TO SLIDE
SOUTHEAST ACROSS THE TAF SITES VERY LATE THIS AFTERNOON AND THIS
EVENING. CIGS LOOKING MOSTLY TO BE IN THE 4K-6K FT RANGE WITH SCT
FLURRIES. ONLY CARRIED VCSH IN TAFS AS THIS CLOUD BAND PASSES.
UPSTREAM OF THIS GENERALLY CLEAR SKIES OVER ND/NORTHWEST MN AND THIS
AIRMASS TO BE OVER THE TAF SITES LATER TONIGHT/MON. GOOD VFR
CONDITIONS LATER TONIGHT/WED BUT SFC PRESSURE GRADIENT TIGHTENS UP
OVER THE AREA FOR TONIGHT/MON. NORTHWEST WINDS BY LATER TONIGHT AND
FOR MON LOOKING TO BE IN THE 12-18KT RANGE WITH GUSTS 20-25KTS. THIS
WILL PRODUCE WIND CHILLS OF 20 BELOW TO 30 BELOW AT THE TAF SITES FOR
LATER TONIGHT/MON.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
250 PM CST SUN JAN 20 2013
WI...WIND CHILL ADVISORY FROM MIDNIGHT TONIGHT TO NOON CST TUESDAY
FOR WIZ017-029-032>034-041>044-053>055-061.
MN...WIND CHILL ADVISORY FROM MIDNIGHT TONIGHT TO NOON CST TUESDAY
FOR MNZ079-086>088-094>096.
IA...WIND CHILL ADVISORY FROM MIDNIGHT TONIGHT TO NOON CST TUESDAY
FOR IAZ008>011-018-019-029-030.
&&
$$
SHORT TERM...AJ
LONG TERM...AJ
AVIATION.....RRS
AREA FORECAST DISCUSSION
NWS GREEN BAY WI
236 PM CST SUN JAN 20 2013
.SHORT TERM...TONIGHT AND MONDAY.
LATEST RUC ANALYSIS AND SATELLITE/RADAR IMAGERY SHOW ARCTIC HIGH
PRESSURE BUILDING SOUTHEAST ACROSS THE NORTHERN AND CENTRAL PLAINS
BENEATH NORTHWEST FLOW ALOFT. EMBEDDED SHORTWAVE TROUGH WITHIN THIS
NW FLOW IS MOVING OVER WESTERN LAKE SUPERIOR EARLY THIS AFTERNOON AND
IS HELPING TO PRODUCE SNOW SHOWERS AND FLURRIES OVER NORTHERN
MINNESOTA WHICH ARE PUSHING INTO NORTHWEST WISCONSIN. THE NEXT PUSH
OF BITTERLY COLD ARCTIC AIR EXISTS BEHIND THIS SHORTWAVE WHERE
TEMPERATURES REMAIN BELOW 0F. FORECAST CONCERNS INCLUDE SMALL
PRECIP CHANCES THIS EVENING...THEN TEMPERATURES AND ASSOCIATED
HEADLINES.
TONIGHT...THE SHORTWAVE TROUGH WILL MOVE ACROSS THE UPPER PENINSULA
OVER THE REST OF THE AFTERNOON AND EARLY THIS EVENING. TAIL OF THE
VORT MAX WILL PUSH AN AREA OF CLOUDS AND FLURRIES ACROSS THE AREA
LATE THIS AFTERNOON AND THIS EVENING. HAVE ADDED THE CHANCE OF
FLURRIES TO THE FORECAST. LOW LEVEL WINDS LOOK TOO WESTERLY FOR
LAKE EFFECT SNOW TO BE MUCH OF AN ISSUE FOR VILAS COUNTY. BUT WITH
ENHANCEMENT FROM THE SHORTWAVE THIS EVENING...WILL KEEP A CHANCE OF
SNOW SHOWERS OVER VILAS AND ACCUMS LESS THAN A HALF INCH. TIMING
THE DEPARTURE OF THE CLOUDS IS DIFFICULT SINCE RH IN THE 900-800MB
LAYER REMAINS FAIRLY HIGH. SATELLITE IMAGERY SHOWS CLEARING TAKING
PLACE OVER NORTHERN MINNESOTA AND ONTARIO...SO THINK SKIES WILL AT
LEAST PARTIALLY CLEAR FROM WEST TO EAST AFTER MIDNIGHT TONIGHT.
TEMPERATURES WERE FIRMLY IN THE TEENS BELOW ZERO OVER NORTHERN
MINNESOTA THIS MORNING. WILL HAVE COMPARATIVELY MORE WIND THAN
FARTHER WEST...BUT STILL THINK WILL REACH IN THE LOW TEENS BELOW
ZERO OVER NORTH-CENTRAL WISCONSIN. WITH NW WINDS 7-12 KTS
TONIGHT...WIND CHILL READINGS WILL APPROACH 20 BELOW OVER
NORTH-CENTRAL WISCONSIN AROUND 06Z...AND OVER THE FOX VALLEY BY
10Z. WILL BEGIN THE NEW WIND CHILL HEADLINES AT THOSE TIMES.
MONDAY...NORTHWEST WINDS WILL CONTINUE TO POUR BITTERLY COLD ARCTIC
AIR ACROSS THE REGION...DROPPING 850MB TEMPS TO 28-29C BELOW ZERO.
ANOTHER WEAK SHORTWAVE WILL BE SWINGING ACROSS THE STATE. SOME
FLURRIES OR LIGHT SNOW NORTH OF LAKE WINNIPEG WITH THIS FEATURE AND
WILL ADD TO THE FORECAST OVER NORTH-CENTRAL AND CENTRAL WISCONSIN.
NW WINDS WILL REMAIN BREEZY...AND TEMPS WILL STRUGGLE TO REACH ABOVE
0F. WIND CHILL READINGS MAY BRIEFLY RISE ABOVE ADVISORY CRITERIA
FOR A FEW HOURS DURING THE AFTERNOON OVER THE FOX VALLEY AND
ADJACENT TO GREEN BAY. BUT HEADLINES WILL HAVE TO BE ISSUED AGAIN
BY 23-24Z...SO WILL JUST RUN HEADLINES THROUGH MONDAY NIGHT. HIGHS
RANGING FROM 6 BELOW OVER N-C WISCONSIN...TO ABOUT 6 ABOVE NEAR LAKE
MICHIGAN.
.LONG TERM...MONDAY NIGHT THROUGH NEXT SUNDAY. COLD ARCTIC AIR
INTRUSION WILL CONTINUE TO GRAB THE HEADLINES FOR THE FIRST HALF
OF THE WEEK. AN ONGOING WIND CHILL ADVISORY EXPECTED OVER WESTERN
AREAS TROUGH TUESDAY NOON. THE REST OF THE FORECAST AREA INCLUDING
THE LAKESHORE REGION WILL BE ADDED STARTING MONDAY EVENING AND
LASTING THROUGH NOON AS WELL AS THE CORE OF THE COLDEST AIR
FILTERS OVER THE AREA. MATTER OF FACT...LATER SHIFTS MAY POSSIBLY
NEED TO UPGRADE TO A WIND CHILL WARNING OVER PORTIONS OF NORTHERN
AND PARTS OF CENTRAL WISCONSIN MONDAY NIGHT. RESURGENT COLD AIR
AND NORTHWEST WINDS WILL CONTINUE LAKE EFFECT SNOW SHOWERS FAR
NORTH BUT DRY AIR MASS AND LOW INVERSIONS WILL LIKELY LIMIT PLUME
DEVELOPMENT.
WINDS WILL BE ON THE DECREASE LATER TUESDAY INTO WEDNESDAY AS A
COLD HIGH PRESSURE SYSTEM SETTLES OVER THE AREA. LAKE EFFECT SNOW
SHOWERS END AS WINDS TURN MORE SOUTHWEST...BUT ANOTHER COLD NIGHT
EXPECTED WITH THE LIGHTER WINDS UNDER THE HIGH PRESSURE SYSTEM.
MIN TEMPERATURES WILL BE IMPACTED BY CLOUDS THROUGH WEDNESDAY...BUT
GUIDANCE TENDS TO OVERDUE THE CLOUDS AT TIMES DUE TO THE RELATIVE
EASE TO SATURATE A COLD DRY AIR MASS. WITH SUCH A COLD AIR MASS
DROPPING IN FOR THE FIRST HALF OF THE WEEK...YOU WONDER HOW COLD
IT COULD HAVE BEEN WITH A FRESH DEEP SNOW COVER. WITH THE LIMITED
SNOW COVER...THE ARCTIC AIR WILL DRIVE AREA FROST DEPTHS DEEPER
THIS WEEK.
WEAK WAA STARTS ON WEDNESDAY AS A SHORT WAVE TROUGH DROPS INTO THE
NORTHERN GREAT LAKES REGION. MORE WIDESPREAD CLOUDS IN THE
BAROCLINIC ZONE FROM MT TO THE OHIO VALLEY TODAY MAY EDGE NORTH
INTO PARTS OF CENTRAL WISCONSIN WEDNESDAY AND CONTINUE TO SPREAD
NORTH THROUGH THURSDAY. LIGHT SNOW REMAINS IN THE FORECAST LATER
IN THE WEEK AS A CLIPPER SYSTEM DROPS INTO THE REGION AND PHASES
WITH SOME SOUTHERN STREAM ENERGY SOUTH AND EAST OF THE AREA. LAKE
EFFECT POTENTIAL INCREASES AGAIN THURSDAY NIGHT AND FRIDAY AS CAA
WITH NORTHWEST WINDS DEVELOP IN THE WAKE OF THE CLIPPER SYSTEM.
ANY LAKE EFFECT SNOW WILL END FRIDAY NIGHT AS A MODERATING
TEMPERATURE PATTERN STARTS WITH A RETURN TO A ZONAL FLOW WITH WAA
FOR THE WEEKEND.
&&
.AVIATION...THE STRONG WINDS THAT DEVELOPED IN THE WAKE OF THE
ARCTIC COLD FRONT HAVE SUBSIDED. LAKE EFFECT SNOW SHOWERS AND
ASSOCIATED MVFR/IFR CONDITIONS CAN BE EXPECTED ACROSS FAR NC WI
(ESPECIALLY VILAS COUNTY) THROUGH TONIGHT. MOST OF THE REMAINING
FORECAST AREA SHOULD HAVE VFR CONDITIONS...ALTHOUGH FLURRIES AND
PATCHY MVFR CIGS ARE POSSIBLE TONIGHT...AS AN UPPER LEVEL TROF AND
REINFORCING SHOT OF ARCTIC AIR ARRIVES.
&&
.GRB WATCHES/WARNINGS/ADVISORIES...
WIND CHILL ADVISORY FROM 4 AM MONDAY TO NOON CST TUESDAY FOR
WIZ013-020-021-031-037>039-045-048-049-073-074.
WIND CHILL ADVISORY FROM 6 PM MONDAY TO NOON CST TUESDAY FOR
WIZ022-040-050.
WIND CHILL ADVISORY FROM MIDNIGHT TONIGHT TO NOON CST TUESDAY
FOR WIZ005-010>012-018-019-030-035-036.
&&
$$
MPC/TDH