Forecast Discussions mentioning any of
"HRRR" "RAP" "RR" "RUC13" "RUC" received at GSD on 01/05/13
AREA FORECAST DISCUSSION
NWS TALLAHASSEE FL
908 PM EST Fri Jan 4 2013
.NEAR TERM [Tonight]...
00 UTC surface analysis shows an area of high pressure a little
closer tonight, about near Memphis, Tennessee. As a result, winds
are a little lighter this evening. However, a similar problem as
last night is in place tonight with extensive mid and upper level
cloudiness streaming northward over the area. This cloud deck is
unlikely to thin significantly before sunrise, particularly over
the southern half of the area. As a result, expect minimum
temperatures to be held back primarily in the upper 30s to lower
40s across the area. Overall, it will be a quiet but cool night
across the region.
&&
.SHORT TERM [Saturday Through Sunday Night]...
The upper low currently over the southwestern states will eject
northeastward and open up into a trough through Saturday. This
piece of energy will pass north of the region Saturday night, with
another shortwave in following in its wake on Sunday. The upper
jets associated with these features will place the southeastern
third of the forecast area in the favorable right entrance region,
generating decent upper divergence. Combined with low-level
upglide over the shallow cool boundary layer, this should generate
a period of showers from late Saturday afternoon through late
Sunday evening.
The exact timing of the upper energy will determine when the
higher rain chances will occur. For now, will broadbrush the
higher PoPs for late Saturday night into Sunday afternoon before
diminishing late Sunday evening. Highest PoP should be confined to
the southeastern half of the area.
The cloud cover, rain, and low-level cool airmass will work to
keep high temperatures a bit below seasonal norms through Sunday.
The same factors will keep low temperatures elevated above normal.
&&
.LONG TERM [Monday through Friday]...
Although there are still some differences, the latest 00z EURO
solution is now in better agreement with the 00z GFS. The GFS is
very progressive showing deep layer ridging at the beginning of
the period exiting to our east as a highly amplified trough across
the nation`s midsection continues to dig and move into the eastern
third of the CONUS on Wednesday. At the surface, rain overspreads
the local region Tuesday and Tuesday night due to isentropic
accent associated with a warm front lifting out of the Gulf. This
will be followed by scattered to numerous showers and
thunderstorms on Wednesday as the cold front approaches and pushed
through the CWA. Dry conditions are forecast to return by the end
of next week. Temperatures will be near seasonal levels through
Monday night and then near to above normal through the rest of the
week.
&&
.AVIATION [through 00 UTC Sunday]...
Very high cigs (around 25k ft) will continue overnight through
Saturday, but most terminals will have unrestricted Vis and VFR
cigs. The exception will be KVLD, as there could be a period of
low-end MVFR cigs and MVFR Vis Saturday morning. This is not
currently being forecast by the GFS or NAM MOS, but it happened this
morning under similar synoptic conditions, and the latest HRRR shows
the western edge of a large deck of VLIFR cigs very near KVLD by
12 UTC Saturday. Light rain will develop later Saturday evening.
&&
.MARINE...
With a cold front stalled south of the waters and high
pressure to the north, moderate northeast flow is expected to
continue into early next week. Winds will occasionaly approach
exercise caution levels through the weekend with Small Craft
conditions possible by late Monday into midweek.
&&
.FIRE WEATHER...
Although relative humidity levels will fall to below critical levels
on Saturday, other necessary requirements for Red Flag conditions
are not likely to be met. Thus, Red Flag conditions are not expected
over the next several days.
&&
.HYDROLOGY...
Expected rainfall over the next several days is only expected to
result in minor rises on area waters.
&&
.PRELIMINARY POINT TEMPS/POPS...
Tallahassee 42 61 46 61 40 / 0 20 60 60 30
Panama City 45 60 48 61 45 / 0 20 50 50 20
Dothan 38 58 43 61 37 / 0 10 30 20 10
Albany 36 58 42 60 37 / 0 10 30 30 20
Valdosta 41 60 45 60 40 / 0 20 60 60 40
Cross City 47 64 50 63 45 / 0 30 70 70 60
Apalachicola 49 61 49 62 48 / 0 30 70 70 40
&&
.TAE WATCHES/WARNINGS/ADVISORIES...
FL...None.
GA...None.
AL...None.
GM...None.
&&
$$
NEAR TERM...Godsey
SHORT TERM...Camp
LONG TERM...Barry
AVIATION...Fournier
MARINE...Camp
FIRE WEATHER...Harrigan
HYDROLOGY...Camp
AREA FORECAST DISCUSSION
NWS TAMPA BAY RUSKIN FL
815 PM EST FRI JAN 4 2013
.UPDATE (TONIGHT - SUNDAY)...
00Z WATER VAPOR AND H4 RAP ANALYSIS SHOW A BROAD RIDGING PATTERN IN
PLACE OVER THE EASTERN GULF OF MEXICO/FL PENINSULA IN ADVANCE OF OF
A LARGE CUT-OFF LOW AND ASSOCIATED HEIGHT FALLS SPREADING EASTWARD
THROUGH THE MID-SECTION OF THE COUNTRY. IN THE LOWER
LEVELS/SURFACE...A QUASI-STATIONARY FRONTAL BOUNDARY BISECTS THE
SOUTHERN THIRD OF THE PENINSULA AND CURRENTLY PASSES SOMEWHERE
BETWEEN FT MYERS AND NAPLES BASED ON PRESSURE AND DEWPOINT ANALYSIS.
05/00Z KTBW SOUNDING PROFILE SEEMS LIKE A BROKEN-RECORD IN THE
LOWEST LEVELS WITH A SATURATED PROFILE BELOW 850MB. THE SATURATED
LOWER LEVELS AND WEAK SUPPRESSION FROM ALOFT ARE HELPING TO KEEP THE
LOWER CLOUDS/STRATUS OVER MANY OF OUR HEADS.
A WEAK UPGLIDE REGIME IN PLACE THE PAST 24 HOURS ALONG THE 295-305K
SURFACES IS BEGINNING TO EXIT EAST OF THE AREA ACCORDING TO
GFS/NAM...AND THIS LOSS OF LOW LEVEL LIFT MAY HELP TO PREVENT AN ALL
DAY LINGERING OF THE VERY LOW CLOUDS DURING SATURDAY. STILL DO NOT
ANTICIPATE MUCH SUN ON SATURDAY...BUT AT LEAST THINGS MIGHT BE
SLIGHTLY MORE OPTIMISTIC FOR AVIATION PURPOSES.
BY THE END OF SATURDAY/SATURDAY NIGHT AND INTO SUNDAY...THE APPROACH
OF A SERIES OF UPPER LEVEL IMPULSES AND BROAD SYNOPTIC SUPPORT FOR
LIFT WILL INITIATE ANOTHER ROUND OF LOW LEVEL UPGLIDE ACROSS THE
EASTERN GULF AND FL PENINSULA. THIS COMBINATION OF FORCING
MECHANISMS WILL GRADUALLY MOISTEN THE DEEP LAYER COLUMN AND BRING
BETTER CHANCES FOR SHOWERS/AREAS OF RAIN BACK TO THE NORTHERN
FORECAST AREA BY EARLY SUNDAY AND THE REMAINDER OF THE AREA BY LATER
SUNDAY AND SUNDAY NIGHT.
&&
.AVIATION...
STRATUS DECK CONTINUES WITH PATCHY FOG. THE STRATUS HEIGHT IS
VARYING BY 1000 FEET OR MORE AT TIMES. VSBY MAY DROP AT TIMES
OVERNIGHT TO 2-4SM WITHIN THE PATCHY FOG AREAS. THESE IFR/MVFR
CONDITIONS ARE EXPECTED TO CONTINUE OVERNIGHT. CONDITIONS ARE
EXPECTED TO IMPROVE DURING THE DAY TOMORROW.
&&
.MARINE...
NORTHEAST FLOW ON THE NORTHERN SIDE OF A STALLED FRONTAL BOUNDARY
WILL PERSIST OVERNIGHT INTO THE DAY ON SATURDAY. WINDS AND SEAS WILL
RUN AT CAUTIONARY LEVELS AT TIMES OVERNIGHT ESPECIALLY ACROSS THE
OFFSHORE WATERS. THE BEST CHANCE AT SEA-FOG DEVELOPMENT WILL BE DOWN
TOWARD THE COASTAL WATERS OFF LEE AND CHARLOTTE COUNTIES WHERE THE
HIGHER DEWPOINT AIR STILL RESIDES IN THE VICINITY.
&&
.PRELIMINARY POINT TEMPS/POPS...
TPA 54 73 61 75 / 20 20 30 60
FMY 61 80 64 81 / 20 20 20 40
GIF 54 75 57 78 / 20 20 30 60
SRQ 56 75 62 77 / 20 20 20 50
BKV 49 72 57 74 / 20 20 40 60
SPG 56 72 61 75 / 20 20 30 50
&&
.TBW WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
GULF WATERS...NONE.
&&
$$
UPDATE/MARINE...MROCZKA
AVIATION...PAXTON
AREA FORECAST DISCUSSION
NWS JACKSONVILLE FL
240 PM EST THU JAN 3 2013
.SHORT TERM /TONIGHT THROUGH FRIDAY NIGHT/...
A SWATH OF PRECIP ASSOCIATED WITH A POST-FRONTAL WAVE IS BEGINNING A
DECREASING TREND THIS AFTN. THE BAND OF PRECIP WILL SINK TO THE SOUTH
TNGT/FRIDAY. MODELS DIFFER ON HOW MUCH FORCING AND SUBSEQUENT PRECIP
WILL REMAIN AS THE WAVE NUDGES SOUTH. LATEST TRENDS POINT TO THE
NAM BEING TOO DRY...WITH THE GFS A BIT WET. THE RUC13 LOOKS THE CLOSEST
THROUGH TNGT...THUS WILL USE SCATTERED POPS FOR MOST AREAS...DECREASING
ACROSS SE GA THIS EVENING...AND DIMINISHING ACROSS EXTREME NE FL
OVERNIGHT. THE WAVE WILL SLOW DOWN AS IT APPROACHES CENTRAL FLORIDA
THUS WILL KEEP CHANCE POPS INTO FRIDAY FOR SOUTHERN SECTIONS OF NE
FL...WITH PRECIP ENDING THERE BY FRIDAY NIGHT. SKIES WILL BEGIN TO
CLEAR ACROSS SE GA BY THE OVERNIGHT...WITH CLOUDS REMAINING ACROSS
MOST OF NE FL THROUGH AT LEAST FRIDAY. SEASONABLY COOL TEMPERATURES
WILL PREVAIL.
.LONG TERM /SATURDAY THROUGH THURSDAY/...INDICATIONS ARE FRONTAL
BOUNDARY OVER S CENTRAL FL AREA WILL WORK BACK NWD AS A WARM FRONT
DURING LATTER HALF OF TH WEEKEND WITH A SUBSTANTIAL INCREASE IN DEEP
LAYER MOISTURE OVER NE FL AND PORTIONS OF SE GA. CONSENSUS RH VALUES
THROUGH 500 MB SHOW AT OR ABOVE 75% IN THE CWA. HAVE INCREASED OUR
POPS TO CHANCE AND A SLIVER OF LIKELY ACROSS THE AREA DUE TO STRONG
UPGLIDE ABOVE THE FRONTAL BOUNDARY. DEEPER MOISTURE AND FRONTAL
BOUNDARY FINALLY PUSH E OF THE AREA SUNDAY NIGHT WITH CLEARING FROM
NW TO SE BY MONDAY MORNING. THE HIGH PRESSURE WILL REMAIN OVER THE
EASTERN US THROUGH MID WEEK WITH ONSHORE FLOW PROVIDING FOR COASTAL
CLOUDS AND A FEW SHOWERS OVER THE COASTAL WATERS. A LOW IS FORECAST
TO DEVELOP AND MOVE NORTHEAST THROUGH THE MIDWEST INTO THURSDAY...
WITH TRAILING COLD FRONT AFFECTING FORECAST AREA...WITH
PRECIPITATION CHANCES. MODEL DISCREPANCIES IN SOLUTION TUE-THU
SUGGESTS NOT CHANGING THE FCST UNTIL BETTER CONSENSUS.
&&
.AVIATION...MVFR TO VFR CIGS EXPECTED REST OF THE AFTN WITH OCNL IFR
CIGS AND VSBY DUE TO LIGHT RAIN AND MIST. MVFR CIGS SEEM LIKELY IN
THE EVENING WITH CONDS IMPROVING BY 12Z FRI TO VFR CIGS EXCEPT
POSSIBLY MVFR CIGS AT GNV AROUND SUNRISE ON FRIDAY.
&&
.MARINE...NLY WINDS HAVE KICKED UP TO 15-20 KT OVER THE MARINE ZONES
WITH SCEC HEADLINE IN PLACE. MAY NEED TO KEEP HEADLINES GOING
TONIGHT AND PERHAPS BRIEFLY INTO FRI MORNING BEFORE WINDS AND SEAS
SUBSIDE. CONFIDENCE IN WINDS AND SEAS FCST GOES DOWN A BIT DURING
THE WEEKEND DUE TO POSSIBLE LOW DEVELOPMENT OFFSHORE. IF NAM
VERIFIES...HEADLINES MAY BE NECESSARY ESPECIALLY SAT NIGHT INTO SUN.
MODELS ARE IN BETTER AGREEMENT OF INCREASED WINDS BY SUN NIGHT INTO
MONDAY AS SFC HIGH PRES BUILDS N OF THE AREA AND FRONTAL BOUNDARY
SAGS SWD OVER THE WRN ATLC INCREASING LOCAL PRESSURE GRADIENT.
SCA HEADLINES MAY BE NECESSARY ON MONDAY THROUGH TUESDAY.
RIP CURRENTS: RIP CURRENTS: LOW RISK OF RIP CURRENTS TODAY AND
FRIDAY.
&&
.FIRE WEATHER...
MINIMUM RELATIVE HUMIDITIES WILL FALL TO 35-40 PERCENT ACROSS FAR
INLAND AREAS FRIDAY...AND TO 30-35 PERCENT ACROSS INTERIOR SE GA
SATURDAY. HOWEVER...WINDS WILL REMAIN LIGHT...SO STATEMENTS ARE NOT
EXPECTED.
&&
.PRELIMINARY POINT TEMPS/POPS...
AMG 35 60 36 60 / 30 0 0 30
SSI 43 59 45 61 / 30 10 10 40
JAX 41 62 41 63 / 30 10 10 50
SGJ 49 63 48 64 / 40 30 20 60
GNV 43 64 41 65 / 40 20 20 60
OCF 48 65 44 68 / 50 30 30 60
&&
.JAX WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
GA...NONE.
AM...NONE.
&&
$$
ALLEN/SHASHY/MCALLISTER
AREA FORECAST DISCUSSION
NWS WICHITA KS
1002 PM CST FRI JAN 4 2013
.UPDATE...
SNOW CHANCES NOT LOOKING AS GOOD OVERNIGHT DUE TO DRY SUB-CLOUD
LAYER AND LIMITED MOISTURE. LATEST EVENING SOUNDINGS ARE QUITE
DRY...AND PRECIPITATION NEAR/UNDER THE UPPER LOW OVER WESTERN KS
AND THE PANHANDLES OF OK/TX HAS HAD A TOUGH TIME REACHING THE
GROUND. ADDITIONALLY...LATEST RUC AND 00Z NAM HAVE BACKED OFF ON
PRECIPITATION AMOUNTS...WITH THE GREATEST 700-600MB MOISTURE
TRAJECTORIES TARGETING THE OZARKS OF AR/MO. HOWEVER...HELD ONTO
40-50 POPS OVER FAR SOUTHEAST KS FROM ABOUT 3AM--8AM...AS LATEST
HRRR CONTINUES TO SHOW SOME QPF LATER TONIGHT THROUGH EARLY
SATURDAY. ANTICIPATING NO MORE THAN A DUSTING SNOW ACCUMULATION.
THINKING PATCHY FLURRIES WILL BE POSSIBLE AS FAR WEST/NORTHWEST AS
CENTRAL KS UNDERNEATH UPPER LOW.
ADDITIONALLY...REMOVED PATCHY FOG WORDING FROM THE FORECAST...AS
SURFACE-BOUNDARY LAYER FLOW WILL LIKELY BE TOO HIGH FOR ANY FOG
FORMATION.
ADK
&&
.PREV DISCUSSION... /ISSUED 549 PM CST FRI JAN 4 2013/
AVIATION...00Z TAFS KRSL/KSLN/KHUT/KICT/KCNU
AN UPPER LEVEL LOW WILL DRIFT NORTHEAST ACROSS THE REGION
TONIGHT...SPREADING DENSE LOW TO MID-LEVEL CLOUDS NORTHEAST.
THINKING ALL SITES WILL REMAIN VFR EXCEPT KCNU...WHERE A QUICK
SHOT OF LIGHT SNOW AND LOW MVFR OR HIGH IFR CIGS WILL BE POSSIBLE
FROM ABOUT 10-14 UTC. ANTICIPATING ACCUMULATIONS TO REMAIN UNDER
ONE-HALF INCH. FURTHER WEST ACROSS THE REST OF CENTRAL AND EASTERN
KS...PERIODIC FLURRIES CANNOT BE RULED OUT FROM ABOUT 08-14
UTC...BUT THINKING MOST AREAS WILL REMAIN PRECIPITATION-FREE DUE
TO A DRY SUB-CLOUD LAYER. OTHERWISE...CLOUDS/PRECIPITATION SHOULD
EXIT EASTERN KS BY LATE MORNING/EARLY AFTERNOON SATURDAY...WITH A
WEAK SURFACE TROUGH SHIFTING WINDS FROM SOUTHWESTERLY TO
WEST/NORTHWESTERLY IN THE AFTERNOON.
ADK
PREV DISCUSSION... /ISSUED 158 PM CST FRI JAN 4 2013/
DISCUSSION...
FORECAST CHALLENGES...LIGHT SNOW CHANCES EARLY SATURDAY MORNING
AND THEN PRECIP CHANCES AGAIN NEXT WEEK.
TONIGHT-MONDAY
UPPER LOW OVER NEW MEXICO WILL LIFT NORTHEAST ACROSS THE TEXAS
PANHANDLE EARLY TONIGHT AND ACROSS SOUTHEAST KANSAS SATURDAY
MORNING. CURRENT FORECAST LOOKS REASONABLE WITH MODEST CHANCE FOR
LIGHT QPF/SNOWS ACROSS SOUTHEAST KANSAS. SOME FLURRIES OR EVEN A
DUSTING OF LIGHT SNOW IS POSSIBLE A BIT FURTHER WEST TO I-135
CORRIDOR...THOUGH BETTER LIFT COINCIDENT WITH RELATIVELY DEEPER
TROPOSPHERIC MOISTENING SHOULD FAVOR SOMEWHAT BETTER CHANCES FOR
LIGHT SNOW ACCUMS ACROSS SOUTHEAST KANSAS. A NORTHERN STREAM UPPER
TROF WILL DIVE SOUTHEAST ACROSS THE MIDWEST SATURDAY NIGHT...WITH
DRY AND SEASONABLY MILD WEATHER EXPECTED FOR THE LATTER PORTION
OF THE WEEKEND. THE EXCEPTIONS BEING OVER THE RESIDUAL SNOW COVER
WHICH WILL KEEP TEMPERATURES A BIT COOLER MAINLY ACROSS CENTRAL
KANSAS.
TUESDAY-FRIDAY
THE MAIN CHALLENGE IN THE OUTER PERIODS CONTINUES TO REVOLVE
AROUND THE HANDLING OF THE SOUTHERN STREAM UPPER TROF MOVING
ACROSS THE SOUTHERN PLAINS NEXT WEEK. THE GFS REMAINS SOMEWHAT
MORE PROGRESSIVE WITH A BIT MORE PHASING OF ENERGY WITHIN THE
NORTHERN STREAM...WHILE THE ECMWF IS MUCH SLOWER. THIS LEADS TO
SOMEWHAT LOWER CONFIDENCE IN THE TRACK AND TIMING OF THE
ASSOCIATED SYNOPTIC FEATURES...SO WILL MAKE LITTLE CHANGE TO THE
GOING FORECAST FOR NOW. THERE DOES SEEM TO BE BETTER CONTINUITY
AND CONFIDENCE IN DEVELOPING A MEAN LONGWAVE UPPER TROF ACROSS
THE WEST BY THE END OF THE WEEK...ALLOWING MUCH COLDER AIR TO BE
POISED AND READY TO DROP SOUTH INTO KANSAS.
DARMOFAL
AVIATION...18Z TAFS KRSL/KSLN/KHUT/KICT/KCNU
THE AVIATION CONCERN IS THE LOW MVFR/IFR CEILINGS AND SNOW CHANCES
FOR KCNU.
AS AN UPPER LEVEL DISTURBANCE APPROACHES THIS AFTERNOON AND
EVENING...MID LEVEL CLOUDS WILL STREAM IN FROM THE SOUTH. AFTER
SUNSET LOWER MVFR CLOUDS WILL MOVE IN IMPACTING PRIMARILY KICT AND
KCNU. SNOW SHOWERS ARE EXPECTED AT KCNU TOWARDS THE MORNING
HOURS...AND HAVE REDUCED VISIBILITIES AND CEILINGS TO IFR RANGE.
VFR CONDITIONS ARE EXPECTED THROUGH THE AFTERNOON AND EARLY
OVERNIGHT HOURS AT ALL TERMINALS UNTIL THOSE LOWER MVFR CEILINGS
MOVE IN. WINDS WILL STAY RELATIVELY LIGHT AND OUT OF THE
SOUTH/SOUTHWEST. TOWARD THE END OF THIS 24 HOUR VALID PERIOD...A
FRONT WILL BEGIN TO MOVE THROUGH THE AREA...CHANGING THE WINDS
AROUND TO THE NORTHWEST...THIS SHOULD IMPACT KRSL BY 15-16Z TOMORROW
AND BEGIN TO IMPACT KSLN BY 18Z.
BILLINGS
&&
.PRELIMINARY POINT TEMPS/POPS...
WICHITA-KICT 26 43 20 44 / 10 10 0 0
HUTCHINSON 24 41 17 42 / 10 10 0 0
NEWTON 25 40 18 40 / 10 10 0 0
ELDORADO 26 41 21 42 / 20 20 0 0
WINFIELD-KWLD 28 45 21 45 / 20 20 0 0
RUSSELL 16 35 13 38 / 10 10 0 0
GREAT BEND 19 36 13 38 / 10 10 0 0
SALINA 21 38 15 39 / 10 10 0 0
MCPHERSON 23 39 16 40 / 10 10 0 0
COFFEYVILLE 29 46 22 40 / 50 50 0 0
CHANUTE 27 44 20 39 / 50 50 0 0
IOLA 27 43 20 39 / 50 50 0 0
PARSONS-KPPF 28 45 21 40 / 50 50 0 0
&&
.ICT WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS DODGE CITY KS
524 PM CST FRI JAN 4 2013
...UPDATED AVIATION SECTION...
.SYNOPSIS...
ISSUED AT 254 PM CST FRI JAN 4 2013
THE 12Z UPPER AIR ANALYSIS SHOWED A CLOSED LOW AT 500 MB SPINNING
OVER NEW MEXICO THIS MORNING. THE ANALYSIS SHOWS THAT THIS SYSTEM
DOES NOT HAVE A LOT OF MOISTURE TO WORK WITH BUT SATELLITE IMAGERY
SHOWED MID AND HIGH LEVEL CLOUDINESS AHEAD OF THIS SYSTEM SPREADING
UP TOWARD SOUTHWEST KANSAS THIS AFTERNOON. IN THE LOWER LEVELS, A
RIDGE OF HIGH PRESSURE AT 850 MB EXTENDED FROM SOUTHEAST TEXAS BACK
INTO THE FOUR CORNERS REGION. AT THE SURFACE, A LOW PRESSURE TROUGH
WAS SLOWLY DEEPENING OVER EASTERN COLORADO. SURFACE DEWPOINTS WERE
GENERALLY IN THE TEENS OVER SOUTHWEST KANSAS WHILE FARTHER SOUTH,
OVER THE TEXAS PANHANDLE INTO WESTERN OKLAHOMA, DEWPOINTS WERE IN
THE LOWER TO MIDDLE 20S.
&&
.SHORT TERM...(THIS EVENING THROUGH TOMORROW)
ISSUED AT 254 PM CST FRI JAN 4 2013
THE UPPER LOW IS PROGGED BY THE MODELS TO MOVE FROM NEW MEXICO THIS
AFTERNOON THROUGH THE TEXAS PANHANDLE INTO EASTERN KANSAS BY
SATURDAY AFTERNOON. MODEL SOUNDINGS MOISTEN UP IN THE MID LEVELS
ACROSS SOUTH CENTRAL KANSAS THIS EVENING AND START TO MOISTEN
DOWNWARD WITH TIME. THE MODELS CONTINUE TO BE SKIMPY ON QPF WITH
THIS SYSTEM WHICH MAKES SENSE GIVEN THE LIMITED MOISTURE. THINK
THAT THERE COULD AT LEAST BE SOME FLURRIES FOR A PERIOD OF TIME
TONIGHT AND HAVE ADDED THAT TO THE GRIDS IN SOUTH CENTRAL KANSAS.
SURFACE WINDS WERE GRADUALLY VEERING WITH TIME THIS AFTERNOON AS THE
EASTERN COLORADO TROUGH DEEPENS IN ADVANCE OF THE UPPER WAVE. THIS
WILL ALLOW WEAK LOW LEVEL MOIST ADVECTION TO OCCUR OVER SOUTHWEST
KANSAS THIS EVENING. WITH THE MOISTURE RIDING UP OVER SNOW COVERED
GROUND, WE SHOULD SEE SOME FOG DEVELOP LATER THIS EVENING AND
CONTINUING THROUGH TONIGHT. MOS OUTPUT IS NOT INDICATING ANY
REDUCTION IN VISIBILITY AT ALL TONIGHT AND THE HRRR MODEL DOES NOT
INDICATE MUCH EITHER BEFORE 08Z. THE SREF PROBABILITIES DO SHOW SOME
INCREASED CHANCES FOR FOG SO WILL CONTINUE THE TREND OF SOME AREAS
OF FOG DEVELOPING. WILL ALSO START THE AREAS OF FOG FARTHER WEST
TOWARD GARDEN CITY AND SYRACUSE LATE THIS EVENING. FOR NOW WILL
HOLD OFF ON ANY HEADLINES AND LET THE NEXT SHIFT MAKE THAT
ASSESSMENT.
ON SATURDAY THE ANY LINGERING FOG IN THE EARLY MORNING SHOULD
DISSIPATE OR MOVE EAST OUT OF CENTRAL KANSAS AS THE SURFACE TROUGH
CONTINUES EAST. THE REMAINDER OF THE DAY SHOULD SEE MAINLY SUNNY
SKIES. WITH A LITTLE BETTER MIXING THAN TODAY, HIGH TEMPERATURES
SHOULD BE ABLE TO CLIMB INTO THE 30S OVER THE SNOW COVERED AREAS
WITH LOWER TO MIDDLE 40S IN SOUTH CENTRAL KANSAS WHERE THE SNOW HAS
MELTED.
.LONG TERM...(SATURDAY NIGHT THROUGH FRIDAY)
ISSUED AT 227 PM CST FRI JAN 4 2013
A WEAK, UPPER LEVEL HIGH PRESSURE RIDGE OVER THE PLAINS SUNDAY AND
INTO MONDAY WILL START TO BREAK DOWN BY LATE TUESDAY, AS A LARGE
UPPER LEVEL LOW PRESSURE SYSTEM APPROACHES FROM THE SOUTHWEST.
BOTH SUNDAY AND MONDAY WILL BE WARMER THAN IT HAS BEEN RECENTLY,
AND PLENTY OF SUNSHINE SHOULD HELP MELT MORE OF THE SNOW COVER.
HIGHS SUNDAY, MONDAY AND TUESDAY WILL RANGE FROM AROUND THE 40F
DEGREE NORTH OF THE I-70, TO THE MID TO UPPER 40S ALONG AND NEAR
THE OKLAHOMA BORDER. THEN ON TUESDAY NIGHT, SYNOPTIC SCALE LIFT
WILL RESULT FROM THE CLOSED LOW APPROACHING FROM THE SOUTHWEST.
MOISTURE WILL BE DEEPENING AND ADVECTING NORTH INTO SOUTHWESTERN
KANSAS, AND ESPECIALLY SOUTH CENTRAL KANSAS. THAT UPPER SYSTEM
WILL CONTINUE TO MARCH INTO THE TEXAS PANHANDLE BY 09/18Z OR WED
AFTERNOON, WHERE IT WILL THEN BEGIN TO LIFT NORTHEAST AND START TO
OPEN UP AS A WAVE, AT THE SAME TIME. AS FOR PRECIPITATION, THE
GOING 20 TO 30 PERCENT OF PRECIPITATION CHANCES, BASICALLY
SOUTHEAST OF A LIBERAL TO PRATT LINE, THROUGH WED/12Z SEEM
REASONABLE. THEN AS THE UPPER LOW LIFTS NORTHEAST LATE WEDNESDAY
INTO EASTERN KANSAS, 20(WEST) TO 35 (EAST) PRECIPITATION CHANCES
WEDNESDAY AFTERNOON AND NIGHT ACROSS ALL OF SOUTHWESTERN KANSAS
ALSO SEEM APPROPRIATE. PRECIPITATION TYPE WILL VARY FROM RAIN OR
SNOW IN THE DAY TIMES AND LIGHT SNOW IN THE NIGHT TIMES. AS THE
UPPER SYSTEM LIFTS OUT WEDNESDAY NIGHT, IT SHOULD ACCELERATE, AND
CHANCES FOR PRECIPITATION WILL QUICKLY END LATE WEDNESDAY NIGHT OR
VERY EARLY THURSDAY MORNING. AS THIS OCCURS, THERE WILL BE
CLEARING AND COOLING THURSDAY. A LITTLE WRAP-AROUND COLD AIR WILL
FILTER BACK INTO THE SOUTHWESTERN KANSAS FRIDAY, AND A LITTLE
LIGHT SNOW MAY DEVELOP. LOWER 20 PERCENT CHANCES FOR LIGHT SNOW
EXIST FOR FRIDAY.
WEDNESDAY AND THURSDAY LOOK TO WARM INTO THE LOWER TO MIDDLE 40S
NORTH OF JETMORE, AND AROUND 50F DEGREES SOUTH OF THE JETMORE-DODGE
CITY AREAS. ON FRIDAY, IT WILL COOL OFF TO HIGHS IN THE 30S.
MINIMUM TEMPERATURES WILL START OUT COLD SATURDAY MORNING, IN THE
TEENS OVER THE SNOW PACKED AREAS NORTHWEST OF A WAKEENEY TO GARDEN
CITY TO ELKHART LINE, AND RANGE TO THE MID 20S IN THE COLDWATER AND
MEDICINE LODGE AREAS. MEDIUM RANGE MODELS WARM MINIMUMS TO AROUND
THE 20F DEGREE MARK IN THE SCOTT CITY AREA BY TUESDAY, AND TO NEAR
30F DEGREES IN THE PRATT AREA. THE SLIGHT WARMING TREND WILL EXTEND
INTO THURSDAY MORNING, WITH LOWS FROM THE MID 20S IN SYRACUSE AND
SCOTT CITY, RANGING TO THE LOWER 30S IN PRATT, KIOWA AND COLDWATER.
MINIMUMS FRIDAY WILL TURN COOLER FROM AROUND 20F DEGREES IN THE KEARNY
COUNTY AREA TO THE UPPER 20S IN THE BARBER COUNTY AREA. SATURDAY
MORNING (DAY 8) SHOULD BE EVEN COLDER.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z SATURDAY EVENING)
ISSUED AT 523 PM CST FRI JAN 4 2013
A TROUGH OF LOW PRESSURE WILL MOVE OUT OF EASTERN COLORADO TONIGHT
INTO WESTERN OKLAHOMA BY TOMORROW AFTERNOON. THIS WILL ALLOW
SOUTHERLY WINDS AT 5 TO 10 KNOTS BE FELT AT THE TAF SITES TONIGHT
SHIFTING TO THE WEST NORTHWEST AROUND 10 KNOTS BY TOMORROW
AFTERNOON. MID CLOUDS AOA100 WILL BE ON THE INCREASE AS THIS
TROUGH MOVES TO THE SOUTHEAST WITH A FEW LOW CLOUDS AOA060 AFTER
MIDNIGHT. THESE CLOUDS SHOULD THEN DISSIPATE BY TOMORROW
AFTERNOON. LOWER VISIBILITIES WILL BE POSSIBLE TOWARDS SUNRISE AS
LOW LEVEL MOISTURE INCREASES ACROSS SOUTHWEST KANSAS. DENSE FOG
MAY OCCUR IN SOME AREAS BUT CONFIDENCE IS LOW IN THE EXACT
LOCATION AND HAVE LEFT THE MENTION OUT OF THE TAFS AT THIS TIME.
&&
.PRELIMINARY POINT TEMPS/POPS...
DDC 16 38 16 43 / 0 0 0 0
GCK 14 36 13 42 / 0 0 0 0
EHA 14 41 16 45 / 0 0 0 0
LBL 16 39 14 45 / 10 0 0 0
HYS 15 35 16 37 / 0 0 0 0
P28 25 42 20 44 / 10 0 0 0
&&
.DDC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...GERARD
SHORT TERM...GERARD
LONG TERM...BURKE
AVIATION...HOVORKA_42
AREA FORECAST DISCUSSION
NWS WICHITA KS
300 AM CST THU JAN 3 2013
.DISCUSSION...
MAIN FORECAST CHALLENGES WILL BE PRECIP CHANCES FRI NIGHT AND TEMPS
IN THE NEAR TERM.
SYNOPSIS:
POSITIVELY TILTED UPPER TROUGH EXTENDS FROM THE WESTERN GREAT LAKES
INTO THE SOUTHERN ROCKIES. A CLOSED UPPER LOW IS SLOWING TRACKING
THROUGH NORTHERN BAJA. LAST BUT NOT LEAST ANOTHER CLOSED LOW IS NOW
APPROACHING THE NORTHERN CA COAST. AT THE SURFACE HIGH PRESSURE IS
CENTERED OVER THE ROCKIES AND EXTENDS INTO THE HIGH PLAINS WITH A
SURFACE LOW OVER THE WESTERN GREAT LAKES.
TODAY-TONIGHT:
THE UPPER TROUGH IS EXPECTED TO SLOWLY SLIDE EAST THROUGH THESE
PERIODS. AT THE SAME TIME THE CLOSED LOW OVER BAJA IS EXPECTED TO
SLOWLY SLIDE EAST AND WILL BE OVER THE DESERT SOUTHWEST BY FRI
MORNING. THIS SETUP WILL KEEP THE BELOW NORMAL TEMPS IN PLACE WITH
HIGHS TODAY FAIRLY CLOSE TO WHERE THEY WERE ON WED.
FRI-SAT:
THE UPPER LOW OVER THE DESERT SOUTHWEST IS EXPECTED TO LIFT
NORTHEAST ON FRI WITH GOOD MODEL AGREEMENT THAT IT WILL BE LOCATED
OVER EASTERN KS/EASTERN OK BY 12Z SAT. WENT AHEAD AND INSERTED SOME
FLURRIES FOR AREAS ALONG AND SOUTHEAST OF THE TURNPIKE FOR FRI NIGHT
AS THIS FEATURE SLIDES OVER THE AREA. THE MAIN REASON THIS WAVE IS
NOT EXPECTED TO BRING MORE THAN THIS IS BECAUSE OF LACK OF MOISTURE.
ON SAT THIS UPPER IMPULSE WILL MOVE OFF INTO THE OHIO VALLEY AS A
MUCH WEAKER PIECE OF ENERGY DIVES SOUTHEAST OUT OF THE NORTHERN
ROCKIES. TEMPS ARE EXPECTED TO MODERATE SOME INTO THE WEEKEND AS
THEY CREEP CLOSER TO SEASONAL AVERAGES.
SUN-WED:
THERE IS GOOD MODEL AGREEMENT THAT THE SPLIT FLOW PATTERN WILL
CONTINUE THROUGH THESE EXTENDED PERIODS. BY MON MORNING ONE
SHORTWAVE WILL BE MOVING OUT OF THE PACIFIC NW WHILE A CLOSED LOW
TRACKS OVER SOUTHERN CA. THE SOUTHERN STREAM SYSTEM IS THE ONE WE
ARE GOING TO HAVE TO WATCH AS IT MOVES INTO THE SOUTHERN HIGH PLAINS
BY TUE NIGHT. THERE IS SOME DISCREPANCIES BETWEEN THE GFS AND ECMWF
WITH REGARDS TO THIS CLOSED LOW...WITH THE ECMWF FURTHER NORTH WITH
ITS POSITION AND ALSO A BIT SLOWER. FOR NOW WILL LEAVE IN PRECIP
CHANCES FOR WED WITH THE THINKING THESE WILL BE ADJUSTED SEVERAL
TIMES WITH LATER FORECAST SHIFTS. A GRADUAL WARMING TREND IS STILL
ANTICIPATED AS WE START NEXT WEEK WITH 50S POSSIBLE BY TUE.
LAWSON
&&
.AVIATION...06Z TAFS KRSL/KSLN/KHUT/KICT/KCNU
THE MAIN CONCERN FOR THIS TAF PERIOD WILL BE THE POTENTIAL AND
EXTENT FOR A MVFR CLOUD DECK. A CURRENT MVFR DECK CAN BE FOUND UPSTREAM
IN WESTERN NEBRASKA...WITH THE CLOUDS SHIFTING SOUTHWARD.
HOWEVER...THERE IS NO CERTAINTY IF THIS DECK WILL EVEN REACH KRSL
AND KSLN OR ANY OTHER SITES GIVEN NAM AND RUC MODELS BREAKING IT
UP BEFORE REACHING THEM. SINCE A SOUTHWARD SHIFTING CLOUD DECK IS
AT LEAST PRESENT...OPTED TO INSERT AN OVC DECK THAT STRADDLES VFR
AND MVFR BY 12Z. ADDITIONALLY THERE MAY BE PATCHY AREAS OF FOG TO
IMPACT KRSL AND KSLN GIVEN THE RADIATION OVER THE SNOW PACK...BUT
LEFT THIS OUT OF THE TAFS SINCE THERE IS VERY MINIMAL CERTAINTY IN
ITS OCCURRENCE AT THE TAF SITE.
A SECOND VFR CLOUD DECK HAS BEGUN TO SLIDE THROUGH THE REST OF THE
TAF SITES. OPTED TO INPUT A MVFR DECK IN FOR KCNU GIVEN GUIDANCE
AND THE IMPACT OF THE CURRENT CLOUD COVER STARTING AT 12Z THEN BKN A
FEW HOURS LATER. ALL SITES SHOULD SCATTER OR EVEN CLEAR OUT IN THE
EARLY TO MID AFTERNOON. IT IS VERY POSSIBLE THAT THERE WILL NEED TO BE
MODIFICATIONS MADE TO THE FORECAST TO BETTER TIME THESE CLOUDS
DECKS AS WELL AS ALTER CIGS ACCORDINGLY.
VP
&&
.PRELIMINARY POINT TEMPS/POPS...
WICHITA-KICT 33 12 37 26 / 0 0 0 10
HUTCHINSON 31 11 35 25 / 0 0 0 10
NEWTON 31 12 36 26 / 0 0 0 10
ELDORADO 32 12 37 25 / 0 0 0 10
WINFIELD-KWLD 35 14 40 27 / 0 0 10 10
RUSSELL 29 3 34 13 / 0 0 0 10
GREAT BEND 30 6 34 18 / 0 0 0 10
SALINA 29 8 34 21 / 0 0 0 10
MCPHERSON 30 10 35 24 / 0 0 0 10
COFFEYVILLE 37 15 40 26 / 0 0 0 10
CHANUTE 34 14 37 25 / 0 0 0 10
IOLA 33 14 37 26 / 0 0 0 10
PARSONS-KPPF 36 14 39 25 / 0 0 0 10
&&
.ICT WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS WICHITA KS
1154 PM CST WED JAN 2 2013
.UPDATE...
ADDED PATCHY FOG FOR CENTRAL KANSAS GIVEN THE RADIATION OVER THE
SNOW COVER WHICH HAS CREATED REDUCED VISIBILITIES IN ELLSWORTH
ALREADY. DO NOT ANTICIPATE A WIDESPREAD EVENT.
ADK
&&
.AVIATION...06Z TAFS KRSL/KSLN/KHUT/KICT/KCNU
THE MAIN CONCERN FOR THIS TAF PERIOD WILL BE THE POTENTIAL AND
EXTENT FOR A MVFR CLOUD DECK. A CURRENT MVFR DECK CAN BE FOUND UPSTREAM
IN WESTERN NEBRASKA...WITH THE CLOUDS SHIFTING SOUTHWARD.
HOWEVER...THERE IS NO CERTAINTY IF THIS DECK WILL EVEN REACH KRSL
AND KSLN OR ANY OTHER SITES GIVEN NAM AND RUC MODELS BREAKING IT
UP BEFORE REACHING THEM. SINCE A SOUTHWARD SHIFTING CLOUD DECK IS
AT LEAST PRESENT...OPTED TO INSERT AN OVC DECK THAT STRADDLES VFR
AND MVFR BY 12Z. ADDITIONALLY THERE MAY BE PATCHY AREAS OF FOG TO
IMPACT KRSL AND KSLN GIVEN THE RADIATION OVER THE SNOW PACK...BUT
LEFT THIS OUT OF THE TAFS SINCE THERE IS VERY MINIMAL CERTAINTY IN
ITS OCCURRENCE AT THE TAF SITE.
A SECOND VFR CLOUD DECK HAS BEGUN TO SLIDE THROUGH THE REST OF THE
TAF SITES. OPTED TO INPUT A MVFR DECK IN FOR KCNU GIVEN GUIDANCE
AND THE IMPACT OF THE CURRENT CLOUD COVER STARTING AT 12Z THEN BKN A
FEW HOURS LATER. ALL SITES SHOULD SCATTER OR EVEN CLEAR OUT IN THE
EARLY TO MID AFTERNOON. IT IS VERY POSSIBLE THAT THERE WILL NEED TO BE
MODIFICATIONS MADE TO THE FORECAST TO BETTER TIME THESE CLOUDS
DECKS AS WELL AS ALTER CIGS ACCORDINGLY.
VP
&&
.PREV DISCUSSION... /ISSUED 515 PM CST WED JAN 2 2013/
AVIATION...00Z TAFS KRSL/KSLN/KHUT/KICT/KCNU
MVFR CLOUDS WILL BE THE MAIN ISSUE FOR THIS TAF FORECAST PERIOD. A
MVFR DECK IS STILL HANGING AROUND UPSTREAM AND MAY SLIDE SOUTHWARD
TOWARDS KRSL AND KSLN...SO OPTED TO LEAVE IN SCATTERED DECKS JUST
IN CASE. THERE HAS BEEN SOME MVFR CIGS FOR KICT AS WELL WHICH ARE
SLOWLY ERODING. KEPT IN A TEMPO JUST IN CASE FOR THE NEXT COUPLE
OF HOURS DUE TO TWO AREAS OF NEAR MVRF CIGS IN THE NORTHEASTERN
PART OF THE COUNTY AND NEAR KINGMAN. A COUPLE OF MODELS ARE STILL
HINTING AT MVFR CIGS BETWEEN 10-13Z ON THURSDAY FOR ALL BUT KCNU...HOWEVER
THERE IS STILL A LACK OF CONFIDENCE DUE TO INCONSISTENCIES. THUS
KEPT THE SCATTERED MVFR MENTION FOR NOW AND WILL UPDATE IN THE
NEXT FORECAST ISSUANCE IF NEEDED. WINDS WILL STAY NORTHWEST AT
SPEEDS OF 5 TO 10KTS.
VP
PREV DISCUSSION... /ISSUED 313 PM CST WED JAN 2 2013/
DISCUSSION...
THE MAIN FORECAST CONCERN IS THE TEMPERATURE FORECAST THROUGH THE
NEXT FEW DAYS.
SYNOPSIS:
A DEEP POSITIVELY TILTED TROUGH IS SITUATED OVER THE CENTRAL CONUS.
THIS TROUGH IS THE COMBINATION OF A COUPLE OF DIFFERENT PV
ANOMALIES. YET ANOTHER DISTURBANCE IS CUT OFF FROM THE MAIN FLOW
ALONG THE AXIS OF THE POSITIVELY TILTED TROUGH...OVER THE BAJA
PENINSULA.
TONIGHT - FRIDAY:
THE UPPER LEVEL PATTERN REMAINS QUITE ACTIVE...BUT NOT IMPACTING OUR
PRECIPITATION FORECAST MUCH. THE MAIN THING IS THAT IT WILL KEEP COLD
AIR IN THE REGION THROUGH THE END OF THE WEEK. THE MAIN TROUGH
BECOMES EVEN MORE POSITIVELY TILTED AS THE NORTHERN PORTION OF THE
WAVE MOVES EAST WHILE THE REMAINDER STAYS CONNECTED TO CUT OFF LOW
OVER THE SOUTHWEST. SURFACE HIGH PRESSURE WILL MOVE IN BEHIND THIS
UPPER WAVE AND TRAVERSE THE AREA LATE THURSDAY AFTERNOON/THURSDAY
NIGHT. TEMPERATURES TONIGHT AND TOMORROW NIGHT WILL BE COOL WITH
THE SNOW COVER AND LIGHT WINDS. THINK TONIGHT LOWS WILL BE IN THE
SINGLE DIGITS/LOW TEENS. DO NOT THINK FRIDAY MORNING WILL BE QUITE
AS COLD AS EXPECTED DURING YESTERDAYS FORECAST AS THE SURFACE HIGH
WILL MOVE ACROSS EARLIER...BUT STILL LOW SINGLE DIGITS EXPECTED OVER
CENTRAL KANSAS. WINDS WILL STILL BE LIGHT UNDER CLEAR SKIES...BUT DO
NOT EXPECT THEM TO BE CALM TO ALLOW FOR MAXIMUM RADIATIONAL
COOLING.
AFTER A WARMER THAN EXPECTED MAXIMUM FORECAST TODAY...THE
REINFORCING SHOT OF AIR TOMORROW WILL KEEP TEMPERATURES COOLER. BY
FRIDAY THE UPPER WAVE WILL PULL COMPLETELY EAST...LEAVING SOME
ENERGY CUT-OFF OVER NEW MEXICO.
SATURDAY - WEDNESDAY:
BY THE WEEKEND THE CUT-OFF LOW PREVIOUSLY MENTIONED WILL MOVE
EAST/NORTHEAST ACROSS TEXAS AND OKLAHOMA WHILE ANOTHER DISTURBANCE
DIVES SOUTHEAST INTO THE CENTRAL PLAINS. THE WAVE DIVING SOUTHEAST
WILL KICK THE CUT-OFF LOW EASTWARD AND OUT OF THE AREA. THE NAM IS
A BIT QUICKER WITH THE FRONT ASSOCIATED WITH THIS SYSTEM THAN THE
ECMWF AND GFS...HAVE CONTINUED TO USE A BLEND OF THE GUIDANCE DUE TO
THESE DISCREPANCIES. TEMPERATURES WILL WARM AHEAD OF THE WAVE AND
REACH NEAR NORMAL FOR THE WEEKEND. THE LATEST 12Z/ECMWF DOES HINT
AT SOME PRECIPITATION DEVELOPMENT AHEAD OF THE FRONT OVER SOUTHEAST
KANSAS...BUT CONFIDENCE ON THIS FEATURE IS LOW AND HAVE LEFT THE
FORECAST DRY FOR SATURDAY AFTERNOON.
BEHIND THESE DISTURBANCES UPPER LEVEL RIDGING WILL BUILD IN AND HELP
TEMPERATURES CONTINUE TO INCREASE THROUGH THE EARLY PART OF THE
WEEK.
THE NEXT BIG SYSTEM TO IMPACT THE AREA WILL BE MID-WEEK NEXT WEEK.
THE GUIDANCE OVER THE PAST COUPLE DAYS HAVE INDICATED ANOTHER
CUT-OFF LOW TO BEGIN TO EJECT EASTWARD TOWARD THE AREA...BUT THE
TIMING HAS BEEN AWRY AMONG THE DIFFERENT MODELS. NOW THINGS HAVE
CHANGED WITH THE LATEST RUNS...THE GFS HAS GRADUALLY SLOWED
DOWN...WHILE THE ECMWF HAVE SPED UP. THIS PUTS THE TIMING OF THE
WAVE IN THE MODELS MUCH NEARER TO EACH OTHER...GIVING SLIGHTLY
HIGHER CONFIDENCE TO THE TIMING. HOWEVER...WITH THAT BEING
SAID...THE DISCREPANCIES WITH THE SYSTEM AS OF LATE AND THESE JUST
BEING THE LATEST RUNS...DID TAPER THE POPS SOME FOR DAY 7. STILL
HAVE CHANCE POPS...BUT LOW CHANCE POPS. THIS SYSTEM WILL BE ONE TO
WATCH OVER THE NEXT WEEK...COULD BE THE NEXT BIG PRECIPITATION
PRODUCER...IF THINGS PAN OUT AS THEY ARE INDICATING NOW.
BILLINGS
&&
.PRELIMINARY POINT TEMPS/POPS...
WICHITA-KICT 16 30 12 39 / 10 0 0 10
HUTCHINSON 14 29 10 38 / 10 0 0 10
NEWTON 15 29 12 36 / 10 0 0 10
ELDORADO 15 31 12 38 / 10 0 0 10
WINFIELD-KWLD 17 32 14 39 / 0 0 0 10
RUSSELL 9 25 2 31 / 10 0 0 0
GREAT BEND 10 26 7 32 / 10 0 0 0
SALINA 11 27 7 35 / 10 0 0 0
MCPHERSON 13 28 10 37 / 10 0 0 0
COFFEYVILLE 18 35 16 40 / 0 0 0 10
CHANUTE 17 33 14 37 / 10 10 0 10
IOLA 18 33 14 36 / 10 10 0 10
PARSONS-KPPF 18 34 14 38 / 10 0 0 10
&&
.ICT WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATED FOR 12Z AVIATION FORECAST DISCUSSION.
&&
.SHORT TERM...(TODAY THROUGH SATURDAY)
ISSUED AT 226 AM CST THU JAN 3 2013
DRY AND COLD CONDITIONS WILL CONTINUE THROUGH THE NEAR TERM. A
STRUNG OUT POSITIVELY TILTED TROUGH STRETCHING FROM THE CENTRAL
PLAINS TO THE UPPER MIDWEST...WILL EVENTUALLY SPLIT INTO TWO
SEPARATE SYSTEMS. THE NORTHERN PIECE OF ENERGY WILL SCOOT EAST
ACROSS THE GREAT LAKES...WHILE THE SOUTHERN CHUNK MOVES ACROSS OUR
REGION. A WEAK SURFACE COLD FRONT WILL ACCOMPANY THIS FEATURE AND
MOVE EAST ACROSS THE FORECAST AREA THIS MORNING. LOOKING UPSTREAM
ACROSS NORTHERN PLAINS AND UPPER MIDWEST...PLENTY OF LOW CLOUDS TO
DEAL WITH. MODELS SWING THIS MOISTURE SOUTHEAST TOWARD THE AREA
THROUGHOUT THE DAY...BUT OTHER THAN THESE PASSING CLOUDS...NO
PRECIPITATION IS EXPECTED.
TEMPERATURES TODAY WILL AGAIN BE AFFECTED BY SNOW AND CLOUD COVER
TODAY...WITH THE COLDEST READINGS PERSISTING OVER SOUTHERN
ILLINOIS AND SW INDIANA. THE GFS IS A LITTLE MORE AGGRESSIVE WITH
THE AMT OF MOISTURE HEADING INTO THE AREA FOR TODAY AND
TONIGHT...AND THIS WILL HAVE AN AFFECT ON TEMPS AS WELL.
ON FRIDAY AND FRIDAY NIGHT...AN UPPER LEVEL RIDGE WILL BUILD INTO
THE REGION AHEAD OF THE NEXT UPPER LEVEL CLOSED LOW SYSTEM...WHICH
DEVELOPS OVER NM/TX. THIS WILL ALLOW LOW LEVEL WINDS TO BECOME
MORE WESTERLY/SOUTHWESTERLY WITH TIME...AND BY 00Z SATURDAY...TEMPS
IN THE 1000-850MB LAYER RISE ABOVE ZERO IN PARTS OF SEMO.
THEREFORE...WE SHOULD SEE HIGH TEMPS SEVERAL DEGREES HIGHER ON FRIDAY.
CLOUDS WILL BE ON THE INCREASE...MAINLY FRIDAY NIGHT...WHICH WILL
LIKELY KEEP LOWS FROM GETTING TOO COLD ESPECIALLY IN OUR WESTERN
SECTIONS.
THE AFOREMENTIONED CLOSED LOW IS FORECAST TO BE OVER THE CENTRAL
PLAINS BY 12Z SATURDAY. IT THEN EJECTS NE ACROSS MO/IL THROUGH
THE DAY. THE GFS IS MOST AGGRESSIVE WITH LIGHT QPF ACROSS THE
ENTIRE AREA WITH THIS EVENT. THE NAM INDICATES SOME QPF OVER
MAINLY WEST KY...AND ECMWF SPLIT BEST MOISTURE TO OUR NW AND SE.
THERE AREA ALSO TIMING DIFFERENCES RIGHT NOW...WITH THE GFS
INDICATING THE QPF ON SATURDAY MORNING...WHILE THE NAM INDICATES
LATER IN THE DAY. EITHER WAY...IT APPEARS AS THOUGH THICKNESSES
AND SOUNDING PROFILES SUGGESTS EITHER SPRINKLES OR SOME FLURRIES
DEPENDING ON THE LOCATION. HIGH TEMPERATURES WILL BE TRICKY DUE TO
ALL THE POTENTIAL CLOUD COVER AND POSSIBLE PRECIP.
.LONG TERM...(SATURDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 226 AM CST THU JAN 3 2013
THE EXTENDED PART OF THE FORECAST CONTINUES TO LOOK RELATIVELY QUIET.
SATURDAY NIGHT WITH DECENT 1000-700MB MOISTURE...THE PASSAGE OF AN
H5 SHORT WAVE...AND 1000-850MB CRITICAL THICKNESSES AOB 1300M...
DECIDED TO THROW IN FLURRIES OVER THE NORTHEAST SECTIONS OF THE CWA.
THE FLURRIES MAY LINGER OVER THE SAME AREA SUNDAY MORNING BUT WILL
LEAVE OUT FOR NOW.
IN THE WAKE OF THE SHORT WAVE PASSAGE SATURDAY NIGHT INTO SUNDAY...
DEPENDING ON WHICH MODEL YOU PREFER...EITHER ZONAL FLOW OR WEAK
RIDGING ALOFT EVENTUALLY EVOLVE INTO SOUTHWEST FLOW WHICH SHOULD
KEEP THE REGION DRY WITH SLOWLY MODERATING TEMPERATURES. HOW THIS
SCENARIO PLAYS OUT STILL NOT CLEAR BUT THE END RESULT SHOULD
BASICALLY BE THE SAME. THE GFS PUSHES THE LOW AMPLITUDE RIDGE OFF TO
THE EAST ON MONDAY...THEN KEEPS THE REGION IN SOUTHWEST FLOW ALOFT
THROUGH THE END OF THE PERIOD WHEREAS THE ECMWF GENERALLY KEEPS THE
AREA IN ZONAL FLOW ALOFT THROUGH TUESDAY...THEN BRINGS THE RIDGE
OVERHEAD.
IRONICALLY ENOUGH...EVEN WITH THE DISPARITY BETWEEN THESE TWO LONG
RANGE MODELS...THEY BOTH SHOW THE NEXT CHANCE OF MEASURABLE
PRECIPITATION IN THE FORM OF RAIN NEXT WEDNESDAY NIGHT...BUT THAT IS
BEYOND THE SCOPE OF THIS FORECAST CYCLE...SO WILL NOT ELABORATE ANY
FURTHER AT THIS TIME.
TEMPERATURES WILL CONTINUE AOB NORMAL THROUGH MONDAY NIGHT...THEN
WARM TO ABOVE NORMAL READINGS FROM TUESDAY THROUGH THE END OF THE
PERIOD.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z FRIDAY MORNING)
ISSUED AT 520 AM CST THU JAN 3 2013
SKIES ARE MAINLY CLEAR AND WINDS AS OF THIS WRITING. VSBYS VFR
ATTM BUT WILL WATCH FOR ANY DIP NEAR SUNRISE. CONTINUE TO SEE
SIGNS FOR A SCATTERED DECK 3-5KFT SLOWLY MOVING IN OVER MUCH OF THE
AREA THROUGHOUT THE DAY...BUT THE MVFR SIGNAL IS NOT AS
STRONG...EXCEPT OVER THE KEVV TERMINAL...OTHERWISE KEPT IT VFR.
LATEST RAP MODEL SHOWS THIS DECK WILL TAKE A WHILE TO GET THERE
(18Z OR SO) DUE TO THE DRY AIR IN PLACE. WEST WINDS WELL UNDER
10KTS WILL BE THE RULE TODAY. APPEARS AS THOUGH LOW LEVEL
MOISTURE WILL LINGER INTO THE EVENING WITH THE PASSAGE OF AN UPPER
TROUGH. NOT CERTAIN AT THIS POINT HOW EXTENSIVE THE CLOUD DECK MAY
BECOME OR WHETHER OR NOT IT WILL BE VFR OR MVFR. KEPT THINGS
OPTIMISTIC FOR NOW.
&&
.PAH WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
MO...NONE.
IN...NONE.
KY...NONE.
&&
$$
AFTER 42 YEARS...MY FINAL FORECAST DISCUSSION.
ALTHOUGH THESE WORDS WILL PASS WITH THE WIND...THE CAMARADERIE
SHARED WITH YOU...MY FELLOW WEATHER WATCHERS...WILL FOREVER BE
CHERISHED. MAY THE SUN SOFTLY WARM YOU, THE RAIN REFRESH YOU, AND
GOD BE WITH YOU...ALWAYS. LOU GIORDANO
.OUTLOOK.../SATURDAY THROUGH MONDAY/...
VFR UNTIL POSSIBLE RESTRICTIONS SATURDAY NIGHT AND SUNDAY AS A
WEAK COLD FRONT MOVES ACROSS THE GREAT LAKES.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
OH...NONE.
PA...NONE.
WV...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
104 AM EST THU JAN 3 2013
.SYNOPSIS...A DISTURBANCE MOVING OFF THE GREAT LAKES MAY SPAWN SCATTERED
LIGHT SNOW SHOWERS LATER TODAY AND TONIGHT. OTHERWISE...SEASONABLY COLD
WEATHER WILL CONTINUE INTO THE WEEKEND.
&&
.NEAR TERM /THROUGH TODAY/...
NO CHANGES NEEDED TO THE NEAR TERM PD FOR THE POST MIDNGT UPDATE.
PREVIOUS...
BASED ON BLEND OF RECENT SURFACE AND SATELLITE DATA ALONG WITH
RECENT RAP AND SREF MODEL OUTPUT...EXPECT BANDS OF JETSTREAK-
RELATED CIRROSTRATUS TO CONTINUE TO MOVE EASTWARD ACROSS THE UPPER
OHIO VALLEY OVERNIGHT.
WITH SURFACE LAYER REMAINING RATHER DRY WITH SNOWPACK
UNDERNEATH...NOCTURNAL RADIATIONAL COOLING SHOULD BE ONLY
SLIGHTLY REDUCED. DID MAKE ADDITIONAL MINOR UPWARD ADJUSTMENTS TO
OVERNIGHT TEMPERATURES...AS EVENING TEMPERATURE FALL HAS BEEN
SLOWER THAN EARLIER THOUGHT. THIS STILL YIELDED LOWS IN THE
5 TO 15 RANGE FOR MOST LOCALES...WHICH WAS GENERALLY 5 DEGREES
WARMER THAN WHAT THE STATISTICAL GUIDANCE SUCH AS GFS AND NAM MOS
SHOWED.
&&
.SHORT TERM /TONIGHT THROUGH SATURDAY/...
MODELS CONTINUE TO EXHIBIT PASSAGE OF A WEAK...MSTR LTD...POSITIVELY
TILTED SHRTWV TROF LATER TODAY. AS SUCH...EVEN WITH SOME LIFT...PRECIPITATION
WILL BE DIFFICULT TO GENERATE AND POPS WERE MAINTAINED AT SLGT...TO
CHC NMBRS OVR NRN AND RIDGE ZONES.
COLD AIR IS PROGGED TO RMN ENTRENCHED OVR THE AREA INTO THE WEEKEND...WITH
A STRONG CONSENSUS ON NORTHWESTERLY FLOW BEING THE MAIN PLAYER IN THE
FORECAST. AS SUCH...THINGS SHOULD REMAIN DRY WITH CONTINENTAL AIR IN
CONTROL.
&&
.LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/...
RELATIVELY QUIET WEATHER EXPD FOR THE LONG TERM PD. A WK COLD FRONT
IS EXPD TO MOVE THROUGH THE RGN SUNDAY. WL KEEP CHC POPS FOR
SHSN...WITH SLIGHTLY HIGHER POPS IN THE NORTH WHERE SOMEWHAT DEEPER
MOISTURE IS FCST. COULD SEE A FEW SHSN IN NW FLOW BEHIND THE FRONT
BUT H8 FLOW QUICKLY TURNS ANTICYCLONIC CUTTING OFF ANY REMAINING
SHSN. HIGH PRES BLDS IN SUN NT THROUGH WED...WITH SEVERAL LOW PRES
SYSTEMS PASSING BY WELL TO OUR NORTH.
SHOULD SEE A SLOW WARMING TREND AS WELL BY NEXT WEEK...ALTHOUGH
PREFERRED TO STAY ON THE COOL SIDE OF GUIDANCE...OR SLIGHTLY BELOW.
&&
.AVIATION /06Z THURSDAY THROUGH MONDAY/...
MOST TERMINALS WILL BE UNDER HIGH OVERCAST SKIES...ALTHOUGH SOME
SLIGHT CLEARING IS POSSIBLE FROM NORTHWEST TO SOUTHEAST. HIGH CLOUDS
WILL PERSIST INTO THE DAYTIME HOURS. ALTHOUGH WINDS WILL BE NEARLY
CALM TONIGHT...EXPECT SW GUSTS TO PICK UP TO AT LEAST 20 KTS THIS
AFTERNOON. A COLD FRONT APPROACHING TONIGHT WILL BE WEAKENING...BUT
SHOULD STILL BRING LOW VFR/HIGH MVFR CIGS OVERNIGHT. BEST CHANCE FOR
ANY LIGHT SNOW SHOWERS WITH THE SYSTEM WILL BE AT FKL/DUJ.
.OUTLOOK.../FRIDAY THROUGH MONDAY/...
CEILING RESTRICTIONS SHOULD END FRIDAY AS HIGH PRESSURE BUILDS IN.
RESTRICTIONS ARE POSSIBLE AGAIN SATURDAY NIGHT AND SUNDAY AS A WEAK
COLD FRONT MOVES ACROSS THE GREAT LAKES.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
OH...NONE.
PA...NONE.
WV...NONE.
&&
$$
15/33
AREA FORECAST DISCUSSION
NWS DULUTH MN
823 PM CST FRI JAN 4 2013
.UPDATE...
TEMPS HAVING BEEN DROPPING QUICKLY IN SPOTS...AND ADJUSTED MINS
TONIGHT DOWN A FEW DEGREES IN SPOTS. SOME PATCHY FOG ALSO
OCCURRING AND WE ADDED SOME TO THE GRIDS. WE DON`T EXPECT THE FOG
TO BE TOO WIDESPREAD OR DENSE.
&&
.PREV DISCUSSION... /ISSUED 551 PM CST FRI JAN 4 2013/
AVIATION...00Z TAFS
MAIN CONCERN REVOLVES AROUND THE MVFR CEILINGS OVER FAR NORTHEAST
MINNESOTA...AND THE POSSIBLE DEVELOPMENT OR REDEVELOPMENT FURTHER
SOUTH LATER TONIGHT INTO SATURDAY.
THE RAP SUGGESTS THE MVFR CEILINGS OVER FAR NORTHEAST MINNESOTA
WILL REMAIN THERE OR MOVE OFF TO THE EAST. INCREASING WAA
OVERNIGHT RESULTS IN THE MODELS INCREASING LOW LEVEL RH OVER OUR
SOUTHERN CWA SHORTLY AFTER 06Z...THEN FURTHER NORTH LATE TONIGHT
INTO SATURDAY. NO EVIDENCE OF THIS YET...BUT WAA WILL BE RAMPING
UP. WE DID ADD A TEMPO GROUP TO SEVERAL TAFS TONIGHT...AND DID GO
WITH PREVAILING MVFR CEILINGS IN MOST TAFS AT SOME POINT SATURDAY.
LOW PRESSURE WILL MOVE INTO THE RED RIVER VALLEY BY 12Z...THEN
CONTINUE EAST TOWARD LAKE SUPERIOR BY MID DAY...THEN INTO UPPER
MICHIGAN BY SATURDAY EVENING. SOME LIGHT SNOW OR FLURRIES WILL
ALSO BE POSSIBLE...BUT MOST MODELS SUGGEST THEY MAY NOT OCCUR
UNTIL LATE IN THE PERIOD OR SATURDAY EVENING SO WE DID NOT ADD TO
THE TAFS YET.
SOME LIGHT FOG MAY ALSO BE CONCERN LATER TONIGHT INTO SATURDAY MORNING...AND
WE DID ADD SOME 3-6SM VSBY RESTRICTIONS.
PREV DISCUSSION... /ISSUED 348 PM CST FRI JAN 4 2013/
SHORT TERM...TONIGHT THROUGH SATURDAY NIGHT...
COOLER AIR WILL GRADUALLY FILTER INTO MUCH OF THE NORTHLAND
OVERNIGHT AS DIFFUSE FRONTAL ZONE CONTINUES TO SAG SOUTHWARD WITH
WINDS GRADUALLY TURNING TO THE N/NE. LOCALLY GUSTY WINDS ALONG THE
NORTH SHORE WILL SUBSIDE THIS EVENING AS PRESSURE RISE CENTER
MOVES OFF TO THE EAST OF THE REGION.
NEXT UPSTREAM WAVE IS CLEARLY EVIDENT IN WV IMAGERY COMING EAST OF
THE CANADIAN ROCKIES..AND ASSOCIATED WEAK SFC LOW TAKING SHAPE
OVER SRN SASKATCHEWAN. THIS WAVE WILL STEADILY MOVE ESEWD TOWARD
THE NORTHLAND TONIGHT AND SATURDAY WITH A SLOW BUT STEADY INCREASE
IN CLOUD COVER LATE TONIGHT AND THE FIRST PART OF THE DAY
SATURDAY. OVERALL..LIFT WITH THIS WAVE WILL BE RELATIVELY BENIGN
AND ACHIEVING DEEP LAYER SATURATION FOR MORE THAN A FEW HOURS LATE
SAT/SAT NIGHT WILL LIKELY BE AN ISSUE IN MOST AREAS. THUS..OVERALL
SNOW CHANCES DONT APPEAR TO BE ALL THAT ROBUST. HOWEVER..MOST
SHORT RANGE GUIDANCE MASS FIELDS ARE IN AGREEMENT THAT LOW LEVEL
WARM ADVECTION WILL BE FAIRLY STRONG..AND AIDED BY MODEST AND
SHALLOW FRONTOGENESIS FOR AT LEAST SEVERAL HOURS OVER ERN MN/NW WI
AND LK SUPERIOR. WE WILL NEED TO WATCH THIS AS THERE COULD BE A
BAND OF LIGHT SNOW THAT SETS UP SOMEWHERE FROM NEAR DULUTH EAST
TOWARD THE U.P. OF MICHIGAN..AND IF THIS OCCURS THERE COULD BE AN
INCH OR TWO OF SNOW OVER A SMALL AREA OF THE ERN CWA BY SUNDAY
MORNING.
THIS WAVE WILL TRAVERSE THE AREA RATHER QUICKLY..FOLLOWED BY COLD
ADVECTION AND AT LEAST A SHORT PERIOD OF LK EFFECT SNOW POTENTIAL
ON THE SOUTH SHORE BEGINNING SAT EVENING INTO SUNDAY. RIGHT NOW IT
APPEARS THAT ACCUMS WILL BE RELATIVELY LIGHT ALONG THE SOUTH
SHORE..BUT WE DID INCREASE POPS INTO THE 60-80 PERCENT RANGE FOR
THE BAYFIELD PENINSULA AND GOGEBIC RANGE FOR SAT NIGHT.
LONG TERM...SUNDAY THROUGH THURSDAY...
THE PERIOD WILL BEGIN WITH THE NORTHLAND IN THE WAKE OF A SURFACE
LOW PRESSURE SYSTEM...WHICH SHOULD BE IN MAINLAND MICHIGAN...AND
SURFACE HIGH PRESSURE IN THE NORTHERN PLAINS BEGINNING TO MOVE
INTO THE FA. THE NORTHERLY WINDS OVER WESTERN LAKE SUPERIOR COULD
RESULT IN LINGERING LAKE EFFECT SNOW FOR THE SOUTH SHORE SUNDAY
MORNING...BUT IT SHOULD CEASE BY THE AFTERNOON DUE TO THE CHANGING
WIND DIRECTION. AFTER THE HIGH PRESSURE MOVES IN...THE NORTHLAND
IS GOING TO HAVE A TOUGH TIME GETTING PCPN FOR A FEW DAYS. IT
LOOKS LIKE A LOW PRESSURE SYSTEM WILL MOVE THROUGH
CENTRAL/NORTHERN MANITOBA AND ONTARIO EARLY NEXT WEEK...BUT IT
WILL PROBABLY BE TOO FAR AWAY TO BRING ANY MEASURABLE PCPN TO THE
FA. THE MODELS HAVE BEEN INDICATING A POTENT MID/UPPER LEVEL LOW
CUTTING ACROSS THE SOUTHWESTERN US THIS WEEKEND AND LIFTING INTO
THE UPPER MIDWEST MID TO LATE NEXT WEEK. MOST OF THE MODELS KEEP
THE ASSOCIATED SURFACE LOW WELL ENOUGH EAST OF THE FA TO PREVENT
THE NORTHLAND FROM BEING AFFECTED BY THE SYSTEM...WITH THE
EXCEPTION OF THE ECMWF. THE ECMWF LIFTS THE SURFACE LOW INTO
CENTRAL/EASTERN WISCONSIN...AND BRINGS CONSIDERABLE PCPN TO THE SE
FA. CONSIDERING THE ECMWF HAS TEMPERATURES NEAR OR SLIGHTLY BELOW
FREEZING IN NW WISCONSIN...FORECASTED A CHANCE OF A MIXTURE OF
RAIN AND SNOW. WILL NEED TO KEEP A CLOSE EYE ON THE MODELS TO SEE
HOW THIS SYSTEM WILL AFFECT THE NORTHLAND. TEMPERATURES THROUGH
THE PERIOD SHOULD BE NEAR OR ABOVE NORMAL.
&&
.POINT TEMPS/POPS...
DLH 13 23 9 22 / 0 20 20 0
INL -2 20 -1 18 / 10 10 10 0
BRD 7 20 3 20 / 0 20 10 0
HYR 8 24 12 24 / 0 20 30 10
ASX 10 26 17 26 / 0 20 30 10
&&
.DLH WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
LS...NONE.
&&
$$
SHORT TERM...MELDE
AREA FORECAST DISCUSSION
NWS DULUTH MN
551 PM CST FRI JAN 4 2013
.AVIATION...00Z TAFS
MAIN CONCERN REVOLVES AROUND THE MVFR CEILINGS OVER FAR NORTHEAST
MINNESOTA...AND THE POSSIBLE DEVELOPMENT OR REDEVELOPMENT FURTHER
SOUTH LATER TONIGHT INTO SATURDAY.
THE RAP SUGGESTS THE MVFR CEILINGS OVER FAR NORTHEAST MINNESOTA
WILL REMAIN THERE OR MOVE OFF TO THE EAST. INCREASING WAA
OVERNIGHT RESULTS IN THE MODELS INCREASING LOW LEVEL RH OVER OUR
SOUTHERN CWA SHORTLY AFTER 06Z...THEN FURTHER NORTH LATE TONIGHT
INTO SATURDAY. NO EVIDENCE OF THIS YET...BUT WAA WILL BE RAMPING
UP. WE DID ADD A TEMPO GROUP TO SEVERAL TAFS TONIGHT...AND DID GO
WITH PREVAILING MVFR CEILINGS IN MOST TAFS AT SOME POINT SATURDAY.
LOW PRESSURE WILL MOVE INTO THE RED RIVER VALLEY BY 12Z...THEN
CONTINUE EAST TOWARD LAKE SUPERIOR BY MID DAY...THEN INTO UPPER
MICHIGAN BY SATURDAY EVENING. SOME LIGHT SNOW OR FLURRIES WILL
ALSO BE POSSIBLE...BUT MOST MODELS SUGGEST THEY MAY NOT OCCUR
UNTIL LATE IN THE PERIOD OR SATURDAY EVENING SO WE DID NOT ADD TO
THE TAFS YET.
SOME LIGHT FOG MAY ALSO BE CONCERN LATER TONIGHT INTO SATURDAY MORNING...AND
WE DID ADD SOME 3-6SM VSBY RESTRICTIONS.
&&
.PREV DISCUSSION... /ISSUED 348 PM CST FRI JAN 4 2013/
SHORT TERM...TONIGHT THROUGH SATURDAY NIGHT...
COOLER AIR WILL GRADUALLY FILTER INTO MUCH OF THE NORTHLAND
OVERNIGHT AS DIFFUSE FRONTAL ZONE CONTINUES TO SAG SOUTHWARD WITH
WINDS GRADUALLY TURNING TO THE N/NE. LOCALLY GUSTY WINDS ALONG THE
NORTH SHORE WILL SUBSIDE THIS EVENING AS PRESSURE RISE CENTER
MOVES OFF TO THE EAST OF THE REGION.
NEXT UPSTREAM WAVE IS CLEARLY EVIDENT IN WV IMAGERY COMING EAST OF
THE CANADIAN ROCKIES..AND ASSOCIATED WEAK SFC LOW TAKING SHAPE
OVER SRN SASKATCHEWAN. THIS WAVE WILL STEADILY MOVE ESEWD TOWARD
THE NORTHLAND TONIGHT AND SATURDAY WITH A SLOW BUT STEADY INCREASE
IN CLOUD COVER LATE TONIGHT AND THE FIRST PART OF THE DAY
SATURDAY. OVERALL..LIFT WITH THIS WAVE WILL BE RELATIVELY BENIGN
AND ACHIEVING DEEP LAYER SATURATION FOR MORE THAN A FEW HOURS LATE
SAT/SAT NIGHT WILL LIKELY BE AN ISSUE IN MOST AREAS. THUS..OVERALL
SNOW CHANCES DONT APPEAR TO BE ALL THAT ROBUST. HOWEVER..MOST
SHORT RANGE GUIDANCE MASS FIELDS ARE IN AGREEMENT THAT LOW LEVEL
WARM ADVECTION WILL BE FAIRLY STRONG..AND AIDED BY MODEST AND
SHALLOW FRONTOGENESIS FOR AT LEAST SEVERAL HOURS OVER ERN MN/NW WI
AND LK SUPERIOR. WE WILL NEED TO WATCH THIS AS THERE COULD BE A
BAND OF LIGHT SNOW THAT SETS UP SOMEWHERE FROM NEAR DULUTH EAST
TOWARD THE U.P. OF MICHIGAN..AND IF THIS OCCURS THERE COULD BE AN
INCH OR TWO OF SNOW OVER A SMALL AREA OF THE ERN CWA BY SUNDAY
MORNING.
THIS WAVE WILL TRAVERSE THE AREA RATHER QUICKLY..FOLLOWED BY COLD
ADVECTION AND AT LEAST A SHORT PERIOD OF LK EFFECT SNOW POTENTIAL
ON THE SOUTH SHORE BEGINNING SAT EVENING INTO SUNDAY. RIGHT NOW IT
APPEARS THAT ACCUMS WILL BE RELATIVELY LIGHT ALONG THE SOUTH
SHORE..BUT WE DID INCREASE POPS INTO THE 60-80 PERCENT RANGE FOR
THE BAYFIELD PENINSULA AND GOGEBIC RANGE FOR SAT NIGHT.
LONG TERM...SUNDAY THROUGH THURSDAY...
THE PERIOD WILL BEGIN WITH THE NORTHLAND IN THE WAKE OF A SURFACE
LOW PRESSURE SYSTEM...WHICH SHOULD BE IN MAINLAND MICHIGAN...AND
SURFACE HIGH PRESSURE IN THE NORTHERN PLAINS BEGINNING TO MOVE
INTO THE FA. THE NORTHERLY WINDS OVER WESTERN LAKE SUPERIOR COULD
RESULT IN LINGERING LAKE EFFECT SNOW FOR THE SOUTH SHORE SUNDAY
MORNING...BUT IT SHOULD CEASE BY THE AFTERNOON DUE TO THE CHANGING
WIND DIRECTION. AFTER THE HIGH PRESSURE MOVES IN...THE NORTHLAND
IS GOING TO HAVE A TOUGH TIME GETTING PCPN FOR A FEW DAYS. IT
LOOKS LIKE A LOW PRESSURE SYSTEM WILL MOVE THROUGH
CENTRAL/NORTHERN MANITOBA AND ONTARIO EARLY NEXT WEEK...BUT IT
WILL PROBABLY BE TOO FAR AWAY TO BRING ANY MEASURABLE PCPN TO THE
FA. THE MODELS HAVE BEEN INDICATING A POTENT MID/UPPER LEVEL LOW
CUTTING ACROSS THE SOUTHWESTERN US THIS WEEKEND AND LIFTING INTO
THE UPPER MIDWEST MID TO LATE NEXT WEEK. MOST OF THE MODELS KEEP
THE ASSOCIATED SURFACE LOW WELL ENOUGH EAST OF THE FA TO PREVENT
THE NORTHLAND FROM BEING AFFECTED BY THE SYSTEM...WITH THE
EXCEPTION OF THE ECMWF. THE ECMWF LIFTS THE SURFACE LOW INTO
CENTRAL/EASTERN WISCONSIN...AND BRINGS CONSIDERABLE PCPN TO THE SE
FA. CONSIDERING THE ECMWF HAS TEMPERATURES NEAR OR SLIGHTLY BELOW
FREEZING IN NW WISCONSIN...FORECASTED A CHANCE OF A MIXTURE OF
RAIN AND SNOW. WILL NEED TO KEEP A CLOSE EYE ON THE MODELS TO SEE
HOW THIS SYSTEM WILL AFFECT THE NORTHLAND. TEMPERATURES THROUGH
THE PERIOD SHOULD BE NEAR OR ABOVE NORMAL.
&&
.POINT TEMPS/POPS...
DLH 13 23 9 22 / 0 20 20 0
INL 2 20 -1 18 / 10 10 10 0
BRD 7 20 3 20 / 0 20 10 0
HYR 8 24 12 24 / 0 20 30 10
ASX 10 26 17 26 / 0 20 30 10
&&
.DLH WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
LS...NONE.
&&
$$
AVIATION...MELDE
AREA FORECAST DISCUSSION
NWS KANSAS CITY/PLEASANT HILL MO
940 PM CST Fri Jan 4 2013
.UPDATE...
/934 PM CST Fri Jan 4 2013/
Have updated the forecast to lower, delay and/or remove pops from the
overnight and through mid day Saturday. 00Z observed soundings from
TOP, SGF and OUN indicate that moisture is really lacking and
probabilities of the area saturating tonight to produce clouds, let
alone precipitation are slim. So for the overnight periods POPs have
been stripped. Model trends from the NAM and RAP seem to capture the
dryness of the atmosphere and have really backed off on any
precipitation for Saturday morning. So with this trend in mind and to
blend the overnight forecast into the forecast for Saturday, have
reduced POPs quite a bit and confined chance POPs to our southern and
eastern zones.
CDB
&&
.DISCUSSION...
Short Range (Today through Sunday)...
Looking through the weekend, the big issue to watch (and its not
really that big) will be the potential for snow Saturday. Looking at
water vapor imagery today shows a cutoff low beginning to exit the
Desert Southwest. This cutoff got a nudge from a shortwave currently
cresting the West Coast ridge; but this same shortwave is expected
to help pick up the cutoff, bringing it back into the prevailing
westerlies later tonight. As this occurs the shortwave will zip
through eastern Kansas and Missouri Saturday.
For Saturday...residency time for the passing shortwave will be
rather short, but all the models are advertising some light snow as
it moves through. Frontogenetical forcing, along the leading edge of the
cold pool associated with the shortwave, looks sufficient to squeeze
out some precipitation along the advancing --and maybe trailing--
edge of the shortwave. Southerly winds across the region while the
shortwave passes will complicate matters a little as models want to
advect in some above freezing air, making precipitation type a
problem. For now, thoughts are models are a little fast in warming
temperatures up Saturday morning, owing to cloud cover and
precipitation possibly sliding in from the south, so have kept
precipitation type all snow through much of the morning hours,
changing the type to a mix of rain and snow for the afternoon hours.
Cold pool with the shortwave does not bode well for lifting
temperatures aloft above freezing, and there does not appear to be
enough instability to force convective elements and sleet. Have
penciled in accumulations of under an inch for the event from west
central Kansas through northeast Missouri, much of which will likely
accumulate between 12Z to 18Z Saturday.
For Sunday...condition will cool off some, with readings ranging just
below normal due to a modest cold front that will slide into the
region behind the exiting shortwave Saturday night.
Cutter
Medium Range (Monday Through Friday)...
Models agree that a large upper low will move through the middle
portions of the country during the extended period. Given the
extreme timing differences...that`s about all they agree on. In a
nutshell, ECMWF is far slower than the operational GFS run. The GFS
ensemble members aren`t in rock solid agreement either, with many of
the members trending towards the operational GFS and a few, though
probably significant number hanging back with the ECMWF. Have
followed the lead of several surrounding offices in slightly
trending precip towards slower ECMWF solution, rather than have 4
days of chance pops from the model blend initialization. This isn`t
all that dramatic in the forecast, but hopefully the beginning of
something we can trend towards as model confidence increases. There
is potential for most if not all of the precipitation to fall as
rain, but have gone with rain or snow at night, again given the
uncertainty of the system...though it could be just a cold rain
through the event.
Bailey
&&
.AVIATION...
For the 00Z TAFs... VFR conditions are likely for the entire period.
The one exception may be late Saturday morning through Saturday
afternoon when a weak system will spread light snow to the area. The
best chances for snow will be well south and east of the terminals
but it is possible that light snow, with visibilities in the 5-6sm
range and ceilings to around 5k ft are possible. At this time the
chances for anything worse than that look too low to mention.
Conditions should improve by Saturday evening as the system quickly
exits the region.
CDB
&&
.EAX WATCHES/WARNINGS/ADVISORIES...
MO...NONE.
KS...NONE.
&&
$$
WFO EAX
AREA FORECAST DISCUSSION
NWS HASTINGS NE
333 PM CST THU JAN 3 2013
.SHORT TERM...THROUGH 00Z SATURDAY. MORNING UPPER AIR ANALYSIS
INDICATES A POSITIVELY TILTED LONGWAVE TOUGH EXTENDING FROM THE
GREAT LAKES REGION INTO THE SOUTHWESTERN CONUS...WITH RIDGING OVER
MUCH OF THE WESTERN CONUS AND QUASI-ZONAL FLOW ACROSS THE EAST.
MID AND UPPER LEVEL JET ENERGY EXTENDS FROM THE SOUTHERN
PLAINS...EAST/NORTHEAST INTO THE MID-ATLANTIC. TROPOSPHERIC FLOW
OVER OUR AREA IS NOT OVERLY IMPRESSIVE AS A RESULT...MAXING OUT AT
AROUND 50KTS NEAR 350MB PER 12Z RAP ANALYSIS SOUNDING DATA FOR
KGRI. WATER VAPOR IMAGERY INDICATES INCREASED VALUES OF MID LEVEL
MOISTURE OVER PORTIONS OF THE SOUTHEASTERN CONUS AHEAD OF THE MID
LEVEL TROUGH AXIS...HOWEVER MID LEVEL MOISTURE FARTHER
NORTHWEST...OVER THE CENTRAL PLAINS...REMAINS FAIRLY MEAGER. AT
THE SURFACE A RIDGE OF HIGH PRESSURE IS NOTED EXTENDING FROM NORTH
TEXAS...NORTHEAST INTO EASTERN KANSAS. AS A RESULT...THE LOW LEVEL
WIND FIELD ACROSS OUR AREA REMAINS FROM THE WEST/SOUTHWEST BUT IS
VERY LIGHT.
GUIDANCE FROM THE NAM...OPERATIONAL GFS AND EC SUGGEST THE MID
LEVEL TROUGH...CURRENTLY MOVING OVER CENTRAL PORTIONS OF THE
CONUS...WILL DEEPEN INTO A CLOSED LOW OVER THE SOUTHERN PLAINS
TONIGHT INTO TOMORROW. DESPITE THIS DEEPENING MID LEVEL LOW...ANY
OMEGA IN ASSOCIATION WITH THIS SYSTEM IS EXPECTED TO REMAIN OVER
THE SOUTHERN PLAINS...WITH DRY CONDITIONS EXPECTED OVER OUR AREA
TONIGHT AND TOMORROW.
CLEAR SKIES AND 2-6 INCHES OF SNOWPACK ACROSS OUR AREA SHOULD
PROMOTE STRONG RADIATIONAL COOLING TONIGHT...WITH 25-30 DEGREE
DROP OFFS NOT OUT OF THE QUESTION FOR MANY LOCATIONS ACROSS THE
CWA. OVERNIGHT LOWS IN THE SINGLE DIGITS ABOVE ZERO ARE FORECAST
FOR MOST LOCATIONS AS ACROSS THE AREA AS A RESULT. AN INCREASING
SOUTHWESTERLY LOW LEVEL WIND FIELD SHOULD PROMOTE SUBTLE LOW LEVEL
WARM AIR ADVECTION DURING THE DAY FRIDAY...WITH 30-35 DEGREE RISES
CURRENTLY FORECAST. THIS PRESENTS FRIDAY AFTERNOON HIGHS GENERALLY
IN THE 30S.
FINALLY...WITH STRONG RADIATIONAL COOLING EXPECTED TONIGHT AND LOW
LEVEL DEWPOINTS LINGERING IN THE SINGLE DIGITS ABOVE ZERO...NEAR-
SURFACE DEWPOINT DEPRESSIONS NEAR ZERO WILL LIKELY BE REALIZED.
ALTHOUGH DRIER LOW LEVEL AIR WILL BE ADVECTING IN FROM EASTERN
COLORADO AND WESTERN KANSAS...IT APPEARS THE STRONG RADIATIONAL
COOLING...WORKING IN CONCERT WITH A LIGHT LOW LEVEL WIND
FIELD...COULD BE CONDUCIVE FOR PATCHY FOG DEVELOPMENT. WENT AHEAD
WITH SUCH WORDING IN THE FORECAST...PRIMARILY ACROSS OUR
SOUTHEASTERN CWA WHICH IS WHERE LOW LEVEL MOISTURE IS EXPECTED TO
BE THE HIGHEST AND THE LOW LEVEL WIND FIELD IS EXPECTED TO BE THE
WEAKEST.
.LONG TERM...FRIDAY NIGHT THROUGH THURSDAY. MAIN FORECAST CONCERNS
WILL BE CHANCE FOR PRECIPITATION WEDNESDAY AND WEDNESDAY NIGHT AND
TEMPERATURES THROUGH THE PERIOD.
A COLD FRONT IS EXPECTED TO MOVE THROUGH THE AREA FRIDAY NIGHT.
DESPITE THE COLD FRONT THE TEMPERATURES FRIDAY NIGHT WILL BE A FEW
DEGREES WARMER THAN THURSDAY NIGHT. THERE IS WARMER AIR ACROSS THE
REGION AND THE COLDER AIR DOES NOT MOVE INTO THE REGION UNTIL ON
SATURDAY. EVEN THIS IS NOT MUCH COLDER AND TEMPERATURES WILL BE
ABOUT THE SAME AS ON FRIDAY. IN ADDITION THERE IS A WEAK UPPER
LEVEL WAVE THAT MOVES INTO THE AREA ON SATURDAY AND BRINGS A FEW
CLOUDS TO THE REGION.
SATURDAY NIGHT INTO SUNDAY AN UPPER LEVEL RIDGE MOVES INTO THE
AREA AND WARM ADVECTION STARTS UP ACROSS THE AREA. WINDS TURN TO
THE SOUTH/SOUTHWEST AND INCREASE. ALL OF THIS SHOULD SHOW UP IN
TEMPERATURES WARMING A BIT ON SUNDAY.
MODELS START TO DIVERGE GREATLY NEXT WEEK. THE GFS AND CANADIAN
BOTH OPEN THE WAVE SOME AND MOVE IT THROUGH MONDAY AND TUESDAY.
THE ECMWF CONTINUES TO KEEP A STRONG UPPER LEVEL LOW THAT MOVES
FROM THE FOUR CORNERS REGION TO THE SOUTHERN PLAINS. THE ECMWF HAS
MAINTAINED SOME RUN TO RUN CONSISTENCY WHILE THE OTHERS HAVE MADE
SOME CHANGES IN THE LAST RUN. FOR NOW WILL CONTINUE TO HAVE THE
PRECIPITATION ON WEDNESDAY AND WEDNESDAY NIGHT WHICH IS MORE
SIMILAR TO THE ECMWF. THE NEXT QUESTION WILL BE PRECIPITATION
TYPE. IN ADDITION TO THE TIMING CHANGE THAT THE GFS
HAS...TEMPERATURES ARE MUCH COLDER...WHICH IS DIFFERENT THAN
PREVIOUS RUNS. HAVE CONTINUED THE WARMER TEMPERATURES AND
THEREFORE WILL KEEP RAIN IN THE FORECAST FOR WEDNESDAY. AS THE
TEMPERATURES COOL OFF WEDNESDAY NIGHT THERE WILL BE SOME SNOW
MIXED INTO THE RAIN. BY THURSDAY...THE UPPER LEVEL LOW HAS MOVED
OFF TO THE EAST AND THEREFORE EXPECT DRY CONDITIONS.
&&
.PREV DISCUSSION... /ISSUED 1115 AM CST THU JAN 3 2013/
AVIATION...18Z KGRI TAF. VFR CONDITIONS TO CONTINUE THROUGH THE
NEXT 24 HOURS. STRATUS WILL REMAIN TO THE SOUTH AND EAST OF THE
TERMINAL THUS PROVIDING LITTLE IN THE WAY OF CLOUD COVER AT KGRI.
THE SURFACE WIND WILL REMAIN FROM THE NORTHWEST AT AROUND 10KTS
FOR A FEW MORE HOURS BEFORE BECOMING LIGHT AND VARIABLE THROUGH
THE REMAINDER OF THE TAF PERIOD. VISIBILITY RESTRICTIONS ARE NOT
EXPECTED THROUGH THE NEXT 24 HOURS.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
KS...NONE.
&&
$$
SHORT TERM/AVIATION...BRYANT
AREA FORECAST DISCUSSION
NWS BUFFALO NY
420 PM EST THU JAN 3 2013
.SYNOPSIS...
LOW PRESSURE MOVING ACROSS SOUTHERN QUEBEC WILL BRING SNOW SHOWERS
TO THE AREA THIS EVENING...BEFORE STEADIER LAKE EFFECT SNOW SETS UP
EAST OF LAKE ONTARIO TONIGHT AND FRIDAY. AS THE LOW MOVES TO THE
EAST ON FRIDAY...RATHER WINDY CONDITIONS WILL DEVELOP ACROSS THE
ENTIRE AREA.
&&
.NEAR TERM /THROUGH FRIDAY/...
MAINLY LIGHT SNOW IS SPREADING EAST ACROSS THE AREA THIS AFTERNOON
AS WARM AIR ADVECTION CONTINUES AHEAD OF THE SURFACE LOW THAT IS
CURRENTLY TRACKING JUST SOUTH OF JAMES BAY. THE STEADIER SNOW IS
FALLING ALONG THE RETREATING ARCTIC FRONT WHICH IS PUSHING THROUGH
THE NORTHERN FINGER LAKES AND NORTH COUNTRY. WE ARE KEEPING AN EYE
ON THE AREA OF SNOW THAT IS FORMING WEST OF LAKE ONTARIO. THIS MARKS
THE LEADING EDGE OF THE COLD FRONT/CONVERGENT BOUNDARY THAT TRAILS
THE SURFACE LOW. AS THIS FRONT REACHES LAKE ERIE AROUND 21Z...EXPECT
THE NARROW BAND OF SNOW TO INTENSIFY A BIT AS IT PICKS UP MORE
MOISTURE FROM THE LAKE. ADDITIONAL LIFT WILL BE GENERATED BY THE
SHORT WAVE THAT IS APPROACHING THE LAKE. THE HRRR PICKS UP ON THIS
TREND AND SUGGESTS THAT A BURST OF SNOW MAY IMPACT THE AREA
STRETCHING FROM METRO BUFFALO TO BATAVIA BETWEEN 21Z AND 23Z. THIS
AREA COULD PICK UP A QUICK 1 TO 2 INCHES OF SNOW...WHICH COMBINED
WITH GUSTY SOUTHWEST WINDS COULD MAKE FOR A CHALLENGING RUSH HOUR
COMMUTE. THE SNOW IS EXPECTED TO DROP SOUTHEAST ACROSS THE SOUTHERN
TIER AND UPPER GENESEE VALLEY LATER IN THE EVENING. EXPECT A SIMILAR
TREND TO DEVELOP EAST OF LAKE ONTARIO FROM ABOUT 23Z THROUGH 02Z.
AFTER THE COLD FRONT CLEARS THE AREA EARLY TONIGHT...THE BOUNDARY
LAYER WINDS WILL SHIFT TO THE WEST AND ALLOW THE REMAINING SNOWBANDS
TO SETTLE TO THE SOUTH. ACROSS THE SOUTHERN...1 TO 3 INCHES OF SNOW
MAY ACCUMULATE BEFORE THE INVERSION LOWER SHARPLY AFTER 06Z.
MODERATING TEMPERATURES ALOFT WILL ALSO REDUCE THE LAKE INSTABILITY.
HOWEVER...THE BUFKIT PROFILES STILL SHOW PLENTY OF MOISTURE TRAPPED
BELOW THE LOWERING SUBSIDENCE INVERSION. THIS COMBINED WITH THE
WESTERLY UPSLOPE FLOW COULD RESULT INCH OF SNOW.
OFF LAKE ONTARIO...STILL EXPECT A MORE SIGNIFICANT EVENT...WITH A
LONGER FETCH AND UPSLOPE ENHANCEMENT ON THE TUG HILL. THE LAKE
INDUCED INSTABILITY WILL ALSO BE GREATER DUE TO THE PRESENCE OF
COLDER AIR ALOFT. THIS ALL POINTS TO SOME DECENT LAKE EFFECT SNOW
EAST OF LAKE ONTARIO TONIGHT...WITH THE BEST FOCUS ON THE TUG HILL.
AS A RESULT A LAKE EFFECT SNOW ADVISORY REMAINS IN EFFECT FOR
TONIGHT THROUGH FRIDAY FOR OUR THREE EASTERN LAKE ONTARIO COUNTIES.
OUTSIDE OF THE NORMAL LAKE EFFECT AREAS...EXPECT A FEW SNOW SHOWERS
WITH LITTLE OR NO ACCUMULATION.
AS THE SURFACE LOW PUSHES EAST ACROSS QUEBEC ON LATE TONIGHT AND
FRIDAY...A STRONG WESTERLY FLOW WILL SET UP ACROSS THE AREA.
IN TERMS OF THE POTENTIAL FOR SNOW...THE BEST CHANCE WILL BE EAST OF
LAKE ONTARIO WHERE TEMPERATURES ALOFT...MOISTURE AND SNOW GROWTH
WILL BE STILL BE FAVORABLE FOR LAKE EFFECT SNOW. THE MODELS SUGGEST
THAT THE SNOW MAY SHIFT A LITTLE TO THE NORTH AS THE BOUNDARY LAYER
WINDS BACK A LITTLE MORE TO THE WEST SOUTHWEST.
EAST OF LAKE ERIE...THE LAKE EFFECT PARAMETERS WILL NOT NEARLY BE AS
FAVORABLE. THERE WILL STILL BE PLENTY OF MOISTURE TRAPPED BELOW THE
SUBSIDENCE INVERSION...BUT THERE WILL BE NO ICE CRYSTALS WITHIN THE
SHALLOW MOIST LAYER. AS A RESULT...IT LOOKS LIKE PCPN WILL BE A MIX
OF LIGHT SNOW AND FREEZING DRIZZLE. THIS LIGHT MIX OF PCPN MAY LIFT
SHIFT NORTH TOWARD BUFFALO AS THE BOUNDARY LAYER WINDS SHIFT TO THE
SOUTHWEST. RIGHT NOW...IT LOOKS LIKE THERE WILL LITTLE ACCUMULATION
OF SNOW.
STRONG WINDS WILL BE THE MAIN ISSUE FOR MOST OF THE CWA ON FRIDAY.
THE NAM AND GFS SHOW A 40 TO 50 KNOT LOW LEVEL JET TRACKING ACROSS
NEW YORK STATE. MOMENTUM TRANSFER SCHMOES SUGGESTS THAT THE
STRONGER WINDS WILL MIX DOWN TO THE SURFACE. AS A RESULT...MOST
AREAS CLOSE TO THE LAKE SHORES WILL LIKELY SEE ADVISORY WIND GUSTS.
THEREFORE A WIND ADVISORY HAS BEEN ISSUED FOR THE COUNTIES OUTLINED
BELOW. THE STRONG WINDS COMBINED WITH ANY FALLING SNOW WILL RESULT
IN CONSIDERABLE BLOWING AND DRIFTING OF SNOW...ESPECIALLY EAST OF
LAKE ONTARIO WHERE TRAVEL WILL BECOME VERY DIFFICULT.
&&
.SHORT TERM /FRIDAY NIGHT THROUGH SUNDAY NIGHT/...
SNOW SHOWERS WILL BE LINGERING ACROSS THE NORTH COUNTRY FRIDAY NIGHT
AS WELL ALIGNED WEST NORTHWESTERLY FLOW WILL CONTINUE ACROSS LAKE
ONTARIO. INVERSION LEVELS WILL BE LOWERING OVERNIGHT ACROSS THE
REGION HOWEVER AS A PASSING SHORTWAVE TROUGH CLEARS THE AREA AND
UPPER LEVEL RIDGING ALONG WITH DRIER AIR NOSES NORTHWARDS INTO THE
LOWER GREAT LAKES. ACROSS FAR WESTERN NEW YORK...INVERSION HEIGHTS
WILL BE EVEN LOWER WITH DRY AIR IN THE DENDRITIC GROWTH ZONE ALOFT.
HOWEVER...MODEL SOUNDINGS INDICATE THAT THERE MAY STILL BE A FAIR
AMOUNT OF MOISTURE TRAPPED UNDERNEATH THE INVERSION IN THE LOWEST
LEVELS OF THE ATMOSPHERE AND THIS COMBINED WITH CONTINUED UPSLOPE
WESTERLY FLOW OFF THE LAKE MAY CREATE A POTENTIAL FOR AREAS OF
FREEZING DRIZZLE ACROSS WESTERN NEW YORK FRIDAY NIGHT.
SATURDAY SHOULD BE A QUIET DAY ACROSS THE REGION AS UPPER LEVEL
RIDGING MOVES OVER THE REGION WITH JUST A SLIGHT CHANCE OF FLURRIES
OR PATCHY FREEZING DRIZZLE LINGERING ACROSS THE NIAGARA FRONTIER AND
SOUTH OF LAKE ONTARIO DUE TO WEAK SURFACE CONVERGENCE. TEMPERATURES
WILL CONTINUE TO RUN SLIGHTLY BELOW NORMAL WITH HIGHS IN THE UPPER
20S.
SATURDAY NIGHT AND SUNDAY...LOOK FOR SNOW TO DEVELOP ACROSS
THE FORECAST AREA AS YET ANOTHER HIGH AMPLITUDE UPPER LEVEL TROUGH
WITH A WEAK SURFACE LOW AT THE SURFACE CROSSES THE GREAT LAKES.
WHILE SYNOPTIC MOISTURE WILL NOT BE PARTICULARLY DEEP...A WIDESPREAD
2 TO 4 INCHES MAY BE POSSIBLE ACROSS THE REGION. BROAD UPPER LEVEL
RIDGING WILL BUILD ACROSS THE REGION IN THE WAKE OF THIS LOW SUNDAY
NIGHT...BRINGING AN END TO THE SNOWFALL AND USHERING IN A WARM-UP SET
TO TAKE PLACE DURING THE EARLY PART OF NEXT WEEK...
&&
.LONG TERM /MONDAY THROUGH THURSDAY/...
THE FORECAST FOR THE COMING WEEK ACROSS OUR REGION HINGES ON THE
FATE OF AN STRONG UPPER LEVEL TROUGH THAT WILL BE DIGGING INTO THE
WESTERN U.S. OVER THE WEEKEND. SUBSTANTIAL DIFFERENCES EXIST
BETWEEN THE GLOBAL MODELS WITH THE GFS DIGGING THE TROUGH ACROSS THE
SOUTHWEST AT THE BEGINNING OF THE WEEK AND THEN LIFTING THE TROUGH
ACROSS THE MISSISSIPPI VALLEY DURING THE MIDDLE OF THE
WEEK...TRACKING A LARGE STORM SYSTEM ACROSS THE GREAT LAKES. ON THE
OTHER HAND...THE ECMWF CUTS OFF THE BASE OF THE TROUGH ACROSS THE
DESERT SOUTHWEST LEADING TO A CUTOFF LOW THAT LINGERS THERE THROUGH
THE FIRST HALF OF THE WEEK AND THEN GRADUALLY LIFTING ACROSS THE
PLAINS DURING THE MIDDLE OF THE WEEK. THIS PROGNOSIS KEEPS ZONAL
FLOW AND/OR UPPER LEVEL RIDGING IN PLACE OVER OUR REGION AT LEAST
INTO THE MIDDLE OF THE WEEK RESULTING IN WHAT SHOULD BE A DRY AND
INCREASINGLY MILD FORECAST. HISTORICALLY...THE FORMATION OF THE
CUTOFF LOW OVER THE SOUTHWEST IS QUITE COMMON FOR THIS TIME OF YEAR
AND MODELS TYPICALLY ARE TOO FAST IN PUSHING THIS FEATURE OUT OF THE
SOUTHWEST. THEREFORE THIS FORECAST STRONGLY FAVORS THE ECMWF
SOLUTION. AS SUCH...EXPECT THE FIRST HALF OF THE UPCOMING WEEK TO BE
DRY WITH TEMPERATURES MODERATING FROM THE LOW 30S MONDAY TO AROUND
40 BY WEDNESDAY.
&&
.AVIATION /22Z THURSDAY THROUGH TUESDAY/...
A COLD FRONT WILL PUSH THROUGH THE AREA EARLY TONIGHT. A NARROW BAND
OF SNOW WILL PRECEDE THE FRONT AS IT CROSSES EACH LAKE. THIS COULD
RESULT IN A BRIEF OF IFR CONDITIONS WITH PASSING FRONT. BEHIND THE
FRONT...A WESTERLY FLOW OF COLD AIR WILL GENERATE STEADIER LAKE
EFFECT SNOW EAST OF LAKE ONTARIO WHERE MORE WIDESPREAD IFR
CONDITIONS WILL PREVAIL...ESPECIALLY LATER TONIGHT AS THE WINDS PICK
UP.
OTHERWISE...EXPECT MVFR CONDITIONS TO BE THE RULE FOR MOST OF THE
NIGHT THROUGH FRIDAY...ALTHOUGH CONDITIONS WILL LIKELY DIP TO IFR AT
TIMES DUE TO THE WESTERLY UPSLOPE FLOW. WE MAY ALSO SEE FREEZING
DRIZZLE MIXING IN WITH LIGHT SNOW AT TIMES OUTSIDE OF THE MAIN LAKE
EFFECT AREAS.
STRONG WEST TO SOUTHWEST WINDS WILL ALSO IMPACT ALL TAF SITES LATE
TONIGHT AND FRIDAY AS A POTENT LOW LEVEL JET TRACKS EAST ACROSS NEW
YORK STATE. THE LATEST GUIDANCE SUGGESTS THAT SOME OF THE STRONGER
WINDS WILL MIX DOWN TO THE SURFACE...ESPECIALLY JUST DOWNWIND OF THE
LAKES WHERE GUSTS UP TO 40 KNOTS ARE POSSIBLE.
OUTLOOK...
SATURDAY...MAINLY VFR.
SUNDAY...MVFR/IFR WITH CHANCE OF SNOW SHOWERS.
MONDAY AND TUESDAY...VFR.
&&
.MARINE...
THE MAIN CONCERN FOR LATE TONIGHT AND FRIDAY WILL BE THE LIKELIHOOD
OF GALE FORCE WINDS AS A DEEPENING AREA OF LOW PRESSURE MOVES
EAST ACROSS SOUTHERN QUEBEC. A POTENT LOW LEVEL JET THAT WILL BE
TRACKING EAST ACROSS NEW YORK STATE WILL ALLOW WINDS TO GUST UP TO
45 KNOTS AT TIMES.
WINDS AND WAVES WILL SUBSIDE GRADUALLY FRIDAY NIGHT AND SATURDAY AS
HIGH PRESSURE BUILDS EAST ACROSS NEW YORK STATE.
&&
.CLIMATE...
OUR THREE CLIMATE SITES HAVE EITHER SET...OR TIED THEIR WARMEST YEAR
ON RECORD. BOTH BUFFALO AND WATERTOWN HAVE FINISHED A FULL DEGREE
OR MORE WARMER THAN THEIR PREVIOUS YEARS ON RECORD. ONE NOTE FOR BUFFALO
IS TEMPERATURE RECORDS WERE RECORDED DOWNTOWN AND CLOSER TO LAKE
ERIE UNTIL THE SUMMER OF 1943.
ROCHESTER TIED FOR THEIR WARMEST YEAR ON RECORD WITH THE YEAR
1931...WHICH WAS A PARTICULARLY WARM YEAR FOR THE EASTERN GREAT
LAKES REGION.
TEMPERATURE RECORDS FOR BOTH BUFFALO AND ROCHESTER GO BACK TO 1871.
WHILE WATERTOWN HAS A SHORTER PERIOD OF RECORD WITH ANNUAL
TEMPERATURES GOING BACK TO ONLY 1950.
BUFFALO
1 2012 52.1
2 1998 50.9
3 2006 50.6
1991 50.6
1921 50.6
ROCHESTER
1 2012 51.8 (TIE)
1931 51.8
3 2006 51.5
4 1921 51.4
5 1998 50.7
WATERTOWN
1 2012 49.2
2 1953 48.1
3 1998 48.0
4 2006 47.4
5 1952 47.2
&&
.BUF WATCHES/WARNINGS/ADVISORIES...
NY...WIND ADVISORY FROM 6 AM TO 6 PM EST FRIDAY FOR NYZ001>003-
010>012-019-020-085.
LAKE EFFECT SNOW ADVISORY UNTIL 4 PM EST FRIDAY FOR NYZ006>008.
WIND ADVISORY FROM 10 AM TO 6 PM EST FRIDAY FOR NYZ004>008.
MARINE...GALE WARNING FROM 7 AM TO 7 PM EST FRIDAY FOR LEZ020-040-041.
SMALL CRAFT ADVISORY UNTIL 7 AM EST FRIDAY FOR LEZ040-041.
GALE WARNING FROM 7 AM TO 7 PM EST FRIDAY FOR LOZ030-
043>045-063>065.
SMALL CRAFT ADVISORY UNTIL 7 AM EST FRIDAY FOR LOZ042.
SMALL CRAFT ADVISORY UNTIL 7 AM EST FRIDAY FOR LOZ043>045.
GALE WARNING FROM 7 AM TO 4 PM EST FRIDAY FOR LOZ042-062.
&&
$$
SYNOPSIS...TJP
NEAR TERM...TJP
SHORT TERM...WOOD
LONG TERM...WOOD
AVIATION...TJP
MARINE...TJP
CLIMATE...THOMAS
AREA FORECAST DISCUSSION
NWS BISMARCK ND
101 AM CST THU JAN 3 2013
.DISCUSSION...
SURFACE HIGH PRESSURE RIDGE EXTENDS NORTH FROM ITS PARENT SURFACE
HIGH PRESSURE CENTER OVER NORTHERN COLORADO TO ACROSS WESTERN
NORTH DAKOTA. STRONG UPPER LEVEL RIDGE ANCHORED OVER THE WESTERN
CONUS. WAA OVER MY NORTHWEST WHERE RETURN FLOW WEST OF THE SFC
RIDGE HAS DEVELOPED.
EXTENSIVE AREA OF LOW CLOUDS REMAINS ACROSS MUCH OF WEST AND
CENTRAL NORTH DAKOTA ALONG WITH ISOLATED FLURRIES BEING REPORTED
AT TIMES OVER VARIOUS OBSERVING SITES ACROSS THE CWA. CLOUDS HAVE
KEPT OUR TEMPERATURES UP THIS MORNING...AND HAVE SIGNIFICANTLY
INCREASED MORNING TEMPERATURES VERY NEAR THE 05Z RAP MODEL WHICH
CAPTURES THE CURRENT SITUATION THE BEST. WHILE CLOUDS SHOULD
CLEAR/TREND SCATTERED OVER MY WEST AND NORTH NOW THROUGH 12Z...WAA
WILL CONTINUE TO SPREAD SOUTH AND EAST ALONG WITH SUFFICIENT
MIXING TO KEEP TEMPERATURES FROM BOTTOMING OUT AS SKIES CLEAR.
MAIN UPDATES WITH THIS FORECAST PACKAGE WAS INCREASING MORNING
TEMPERATURES...MAINTAINING/EXPANDING ISOLATED FLURRIES ALL AREAS
THROUGH 12Z...AND ADJUSTING SKY COVER BASED ON LATEST SATELLITE
IMAGERY.
&&
.AVIATION...AT 11 PM CST...AN AREA OF HIGH PRESSURE OVER EASTERN
MONTANA INTO SASKATCHEWAN WAS MOVING EAST. A LARGE AREA OF MVFR
CEILINGS EXTENDED ACROSS ALL OF WEST AND CENTRAL NORTH DAKOTA. MVFR
CONDITIONS ARE FORECAST AT ALL TAF SITES TONIGHT. CONDITIONS
GRADUALLY BECOMING VFR FROM NORTHWEST TO SOUTHEAST BETWEEN 08-14Z.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...NH
AVIATION...WAA
AREA FORECAST DISCUSSION
NWS CHARLESTON WV
936 PM EST FRI JAN 4 2013
.SYNOPSIS...
SURFACE HIGH PRESSURE TONIGHT. TWO MID/UPPER LEVEL TROUGHS PASS THIS
WEEKEND. HIGH PRESSURE THEN BUILDS IN...MONDAY AND EARLY WEDNESDAY.
LOW PRESSURE BRINGS RAIN SHOWERS LATE WEDNESDAY NIGHT AND THURSDAY.
&&
.NEAR TERM /THROUGH SATURDAY/...
UPDATE...
RAP WAS NOT AS ACCURATE TONIGHT...AND HAVE CLEARED OUT THE CLOUDS
IN THE SOUTHERN MOUNTAINS. WILL BE SOMETHING TO WATCH OVER THE
NEXT FEW HOURS HOWEVER AS THE MOISTURE HANGS ON FOR THE NORTHEAST
MOUNTAINS. UPPER LEVEL TROUGH/VORT MAX NOW IN THE PIEDMONT OF
VIRGINIA...AND EXPECT A QUIET NIGHT THE REST OF THE WAY.
PREVIOUS DISCUSSION...
USED RAP AND VIS SAT TRENDS AS BASE FOR TIMING IMPROVING SKY
CONDITION INTO TONIGHT. THINK AREAS ALONG AND E OF I79 CORRIDOR
WILL KEEP CLDS WITH N MTNS HOLDING ON UNTIL PERHAPS 15Z. LOWS
TONIGHT TRICKY ONCE AGAIN AND WILL DEPEND ON EXTENT OF CLEARING
AND BL PUFF. LAMP GUIDANCE CONT TO BE ON WARM SIDE...LKLY OWING TO
BL PUFF AND ALSO CLDS ACROSS THE MTNS. DEEPER VALLEYS/HOLLOWS MAY
DECOUPLE THOUGH...GIVING UPPER TEENS. WILL LEAN TOWARD LAMP WHICH
HAS PERFORMED BETTER OVER RECENT COLD BIAS IN MET/MAV AND
INCORPORATE A COLDER SOLUTION FOR TYPICAL COLD SPOTS OUTSIDE OF
THE CLDS.
ANY REMAINING STRATUS ACROSS N MTNS WILL SCT OUT BY LATE
MORNING. SOME HIGH CLDS WILL BE ROLLING IN AFTN FROM SW...HELPING
TO PUT A FILTER ON SUNSHINE. KEPT POPS OUT THROUGH 00Z...WITH DRY
LLVLS IN PLACE. HOWEVER...MAY SEE ENOUGH TOP DOWN MOISTENING FOR
SOME LIGHT PCPN ACROSS SW VA BY 00Z.
&&
.SHORT TERM /SATURDAY NIGHT THROUGH MONDAY/...
UPPER SPLIT FLOW PATTERN CONTINUES. MODELS IN GOOD AGREEMENT ON
SOUTHERN STREAM UPPER LOW OVER THE SOUTHWEST U.S. WEAKENING AS IT
OPENS UP...AND LIFTS NORTHEASTWARD ACROSS THE OHIO VALLEY SATURDAY
NIGHT IN CONFLUENT FLOW ALOFT. THIS SYSTEM IS FORECAST TO BE TOO
WEAK TO LIFT THE BAROCLINIC ZONE...STILL ACROSS THE SOUTHEASTERN
STATES...NORTHWARD ENOUGH TO AFFECT ALL BUT THE SOUTHEAST PORTION
OUR AREA. WITH THE VORT CENTER OF THE SYSTEM TRACKING ACROSS THE
MIDDLE OHIO VALLEY INTO THE GREAT LAKES...THE EFFECTS OF ITS
DYNAMICS WILL MAINLY CLIP OUR SOUTHEAST OHIO ZONES. THUS...AS A
WHOLE...OUR AREA LOOKS TO BE IN A MIN FOR QPF. WILL KEEP LOW POPS
ACROSS THE AREA SATURDAY NIGHT...WITH THE BEST CHANCE OVER THE
NORTHWEST AND SOUTHEAST AREAS. DRY SLOW MOVES IN BY SUNDAY MORNING
AS THE SOUTHERN STREAM SYSTEM DEPARTS WITH A BREAK IN THE PRECIP.
DURING SUNDAY...A NORTHERN STEAM UPPER TROUGH AND COLD FRONT DROPS
RAPIDLY SOUTHEAST ACROSS THE AREA SUNDAY AFTERNOON...BRINGING
SCATTERED RAIN SHOWERS...CHANGING TO SNOW SHOWERS BEFORE ENDING
SUNDAY NIGHT. AGAIN...EXPECT LIGHT QPF WITH ANY SNOW ACCUMULATIONS
LIMITED TO MAINLY THE NORTHERN MOUNTAINS...GENERALLY AN INCH OR TWO
BY MONDAY MORNING.
BEHIND THIS QUICK HITTER WILL BE HIGH PRESSURE FOR MONDAY WITH
INCREASING SUNSHINE. MAX TEMPERATURES SUNDAY AND MONDAY AFTERNOON
WILL BE SIMILAR IN THE LOW TO MID 40S...SUNDAY MAINLY
DUE TO THE CLOUDS AND MONDAY MAINLY DUE TO THE SUNSHINE.
&&
.LONG TERM /MONDAY NIGHT THROUGH FRIDAY/...
HIGH PRESSURE REMAINS IN CONTROL MONDAY NIGHT AND TUESDAY TO PROVIDE
DRY CONDITIONS.
A DEVELOPING LOW PRESSURE SYSTEM WILL APPROACH FROM THE WEST
WEDNESDAY NIGHT. DIFFERENCES BETWEEN THE ECMWF AND GFS EXIST. THE
ECMWF IS THE PREFERRED MODELS WITH A LOW LATITUDE CYCLONE BECOMING
LESS PROGRESSIVE...WITH SFC LOW TRACK MOVING FROM THE CENTRAL PLAINS
NORTHEAST INTO THE GREAT LAKES REGION...CONTRARY TO THE GFS THAT
DEVELOPS THE LOW OVER THE SOUTHERN PLAINS...TRACKING THE LOW
OVERHEAD WV.
THEREFORE...MINOR TWEAKS WHERE NEEDED FROM PREVIOUS FORECAST...WITH
CHANCES OF RAIN SHOWERS SPREADING FROM WEST TO EAST LATE WEDNESDAY
NIGHT...WITH THE BULK OF PCPN OCCURRING ON THURSDAY.
TEMPERATURE PROFILES AND BOUNDARY LAYER SOUTHWEST FLOW SUGGEST ALL
PCPN STARTING AS LIQUID BY 15Z THURSDAY. THEREFORE...HIGHEST POPS
WHERE CODED ON THURSDAY. ECMWF H850 STRENGTHENING SOUTH TO SOUTHWEST
FLOW AROUND 50 KNOTS...AND TEMPERATURES NEAR 11C BY 18Z
THURSDAY...SUPPORT A GRADUAL WARMING TREND THRU THURSDAY AFTERNOON.
DECREASED POPS BY 06Z FRIDAY...WITH CHANCE POPS MAINLY OVER NORTHERN
AND EASTERN MOUNTAINS. DRIER AIR MASS EXPECTED BY MID FRIDAY MORNING
WITH PCPN EXITING NORTHEAST.
WENT GENERALLY WITH HPC GUIDANCE FOR TEMPERATURES ADDING FEW LOCAL
DETAILS.
&&
.AVIATION /03Z SATURDAY THROUGH WEDNESDAY/...
MVFR STRATOCUMULUS TO LINGER OF THE MOUNTAINS AND COAL FIELDS
THROUGH THE BULK OF THE OVERNIGHT...AND CARRY THESE RESTRICTIONS
AT BKW AND EKN. RAP MODEL PROVED RELIABLE WITH LOW LEVEL MOISTURE
LAST NIGHT...AND WILL RIDE THIS FOR TONIGHT. OTHERWISE...VFR
EXPECTED WITH WINDS DECREASING BELOW 10KTS THROUGH THE OVERNIGHT.
FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 00Z SUNDAY...
FORECAST CONFIDENCE: MEDIUM TO HIGH.
ALTERNATE SCENARIOS: TIMING OF BREAKUP OF STRATUS DECK OVER THE
MOUNTAINS AND COAL FIELDS MAY OCCUR EARLIER THAN FORECAST.
EXPERIMENTAL TABLE OF FLIGHT CATEGORY OBJECTIVELY SHOWS CONSISTENCY
OF WFO FORECAST TO AVAILABLE MODEL INFORMATION:
H = HIGH: TAF CONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL.
M = MEDIUM: TAF HAS VARYING LEVEL OF CONSISTENCY WITH MODELS.
L = LOW: TAF INCONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL.
DATE SAT 01/05/13
UTC 1HRLY 02 03 04 05 06 07 08 09 10 11 12 13
EST 1HRLY 21 22 23 00 01 02 03 04 05 06 07 08
CRW CONSISTENCY H H H H H H H H H H H H
HTS CONSISTENCY H H H H H H H H H H H H
BKW CONSISTENCY H H H H H H H H H H H H
EKN CONSISTENCY H H H H H H L L L H H H
PKB CONSISTENCY H H H H H H H H H H H H
CKB CONSISTENCY M H H H H H H H H H H M
AFTER 00Z SUNDAY...
NO WIDESPREAD IFR CONDITIONS EXPECTED.
&&
.RLX WATCHES/WARNINGS/ADVISORIES...
WV...NONE.
OH...NONE.
KY...NONE.
VA...NONE.
&&
$$
SYNOPSIS...ARJ/JMV/30
NEAR TERM...30/26
SHORT TERM...JMV
LONG TERM...ARJ
AVIATION...26
AREA FORECAST DISCUSSION
NWS CHARLESTON WV
650 PM EST FRI JAN 4 2013
.SYNOPSIS...
SURFACE HIGH PRESSURE TONIGHT. TWO MID/UPPER LEVEL TROUGHS PASS THIS
WEEKEND. HIGH PRESSURE THEN BUILDS IN...MONDAY AND EARLY WEDNESDAY.
LOW PRESSURE BRINGS RAIN SHOWERS LATE WEDNESDAY NIGHT AND THURSDAY.
&&
.NEAR TERM /THROUGH SATURDAY/...
UPDATE...
UPPED THE SKY COVER OVER THE COAL FIELDS WITH RAP LOW LEVEL
MOISTURE KEEPING THE CLOUD DECK IN THIS AREA THROUGH THE NIGHT.
ALSO DROPPED THE LOWS IN SNOWSHOE AS THEY WERE ALREADY
SIGNIFICANTLY LOWER THAN THE FORECAST.
PREVIOUS DISCUSSION...
USED RAP AND VIS SAT TRENDS AS BASE FOR TIMING IMPROVING SKY
CONDITION INTO TONIGHT. THINK AREAS ALONG AND E OF I79 CORRIDOR
WILL KEEP CLDS WITH N MTNS HOLDING ON UNTIL PERHAPS 15Z. LOWS
TONIGHT TRICKY ONCE AGAIN AND WILL DEPEND ON EXTENT OF CLEARING
AND BL PUFF. LAMP GUIDANCE CONT TO BE ON WARM SIDE...LKLY OWING TO
BL PUFF AND ALSO CLDS ACROSS THE MTNS. DEEPER VALLEYS/HOLLOWS MAY
DECOUPLE THOUGH...GIVING UPPER TEENS. WILL LEAN TOWARD LAMP WHICH
HAS PERFORMED BETTER OVER RECENT COLD BIAS IN MET/MAV AND
INCORPORATE A COLDER SOLUTION FOR TYPICAL COLD SPOTS OUTSIDE OF
THE CLDS.
ANY REMAINING STRATUS ACROSS N MTNS WILL SCT OUT BY LATE
MORNING. SOME HIGH CLDS WILL BE ROLLING IN AFTN FROM SW...HELPING
TO PUT A FILTER ON SUNSHINE. KEPT POPS OUT THROUGH 00Z...WITH DRY
LLVLS IN PLACE. HOWEVER...MAY SEE ENOUGH TOP DOWN MOISTENING FOR
SOME LIGHT PCPN ACROSS SW VA BY 00Z.
&&
.SHORT TERM /SATURDAY NIGHT THROUGH MONDAY/...
UPPER SPLIT FLOW PATTERN CONTINUES. MODELS IN GOOD AGREEMENT ON
SOUTHERN STREAM UPPER LOW OVER THE SOUTHWEST U.S. WEAKENING AS IT
OPENS UP...AND LIFTS NORTHEASTWARD ACROSS THE OHIO VALLEY SATURDAY
NIGHT IN CONFLUENT FLOW ALOFT. THIS SYSTEM IS FORECAST TO BE TOO
WEAK TO LIFT THE BAROCLINIC ZONE...STILL ACROSS THE SOUTHEASTERN
STATES...NORTHWARD ENOUGH TO AFFECT ALL BUT THE SOUTHEAST PORTION
OUR AREA. WITH THE VORT CENTER OF THE SYSTEM TRACKING ACROSS THE
MIDDLE OHIO VALLEY INTO THE GREAT LAKES...THE EFFECTS OF ITS
DYNAMICS WILL MAINLY CLIP OUR SOUTHEAST OHIO ZONES. THUS...AS A
WHOLE...OUR AREA LOOKS TO BE IN A MIN FOR QPF. WILL KEEP LOW POPS
ACROSS THE AREA SATURDAY NIGHT...WITH THE BEST CHANCE OVER THE
NORTHWEST AND SOUTHEAST AREAS. DRY SLOW MOVES IN BY SUNDAY MORNING
AS THE SOUTHERN STREAM SYSTEM DEPARTS WITH A BREAK IN THE PRECIP.
DURING SUNDAY...A NORTHERN STEAM UPPER TROUGH AND COLD FRONT DROPS
RAPIDLY SOUTHEAST ACROSS THE AREA SUNDAY AFTERNOON...BRINGING
SCATTERED RAIN SHOWERS...CHANGING TO SNOW SHOWERS BEFORE ENDING
SUNDAY NIGHT. AGAIN...EXPECT LIGHT QPF WITH ANY SNOW ACCUMULATIONS
LIMITED TO MAINLY THE NORTHERN MOUNTAINS...GENERALLY AN INCH OR TWO
BY MONDAY MORNING.
BEHIND THIS QUICK HITTER WILL BE HIGH PRESSURE FOR MONDAY WITH
INCREASING SUNSHINE. MAX TEMPERATURES SUNDAY AND MONDAY AFTERNOON
WILL BE SIMILAR IN THE LOW TO MID 40S...SUNDAY MAINLY
DUE TO THE CLOUDS AND MONDAY MAINLY DUE TO THE SUNSHINE.
&&
.LONG TERM /MONDAY NIGHT THROUGH FRIDAY/...
HIGH PRESSURE REMAINS IN CONTROL MONDAY NIGHT AND TUESDAY TO PROVIDE
DRY CONDITIONS.
A DEVELOPING LOW PRESSURE SYSTEM WILL APPROACH FROM THE WEST
WEDNESDAY NIGHT. DIFFERENCES BETWEEN THE ECMWF AND GFS EXIST. THE
ECMWF IS THE PREFERRED MODELS WITH A LOW LATITUDE CYCLONE BECOMING
LESS PROGRESSIVE...WITH SFC LOW TRACK MOVING FROM THE CENTRAL PLAINS
NORTHEAST INTO THE GREAT LAKES REGION...CONTRARY TO THE GFS THAT
DEVELOPS THE LOW OVER THE SOUTHERN PLAINS...TRACKING THE LOW
OVERHEAD WV.
THEREFORE...MINOR TWEAKS WHERE NEEDED FROM PREVIOUS FORECAST...WITH
CHANCES OF RAIN SHOWERS SPREADING FROM WEST TO EAST LATE WEDNESDAY
NIGHT...WITH THE BULK OF PCPN OCCURRING ON THURSDAY.
TEMPERATURE PROFILES AND BOUNDARY LAYER SOUTHWEST FLOW SUGGEST ALL
PCPN STARTING AS LIQUID BY 15Z THURSDAY. THEREFORE...HIGHEST POPS
WHERE CODED ON THURSDAY. ECMWF H850 STRENGTHENING SOUTH TO SOUTHWEST
FLOW AROUND 50 KNOTS...AND TEMPERATURES NEAR 11C BY 18Z
THURSDAY...SUPPORT A GRADUAL WARMING TREND THRU THURSDAY AFTERNOON.
DECREASED POPS BY 06Z FRIDAY...WITH CHANCE POPS MAINLY OVER NORTHERN
AND EASTERN MOUNTAINS. DRIER AIR MASS EXPECTED BY MID FRIDAY MORNING
WITH PCPN EXITING NORTHEAST.
WENT GENERALLY WITH HPC GUIDANCE FOR TEMPERATURES ADDING FEW LOCAL
DETAILS.
&&
.AVIATION /23Z FRIDAY THROUGH WEDNESDAY/...
MVFR STRATOCUMULUS TO LINGER OF THE MOUNTAINS AND COAL FIELDS
THROUGH THE BULK OF THE OVERNIGHT...AND CARRY THESE RESTRICTIONS
AT BKW AND EKN. RAP MODEL PROVED RELIABLE WITH LOW LEVEL MOISTURE
LAST NIGHT...AND WILL RIDE THIS FOR TONIGHT. OTHERWISE...VFR
EXPECTED WITH WINDS DECREASING BELOW 10KTS THROUGH THE OVERNIGHT.
FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 00Z SUNDAY...
FORECAST CONFIDENCE: MEDIUM TO HIGH.
ALTERNATE SCENARIOS: TIMING OF BREAKUP OF STRATUS DECK OVER THE
MOUNTAINS AND COAL FIELDS MAY OCCUR EARLIER THAN FORECAST.
EXPERIMENTAL TABLE OF FLIGHT CATEGORY OBJECTIVELY SHOWS CONSISTENCY
OF WFO FORECAST TO AVAILABLE MODEL INFORMATION:
H = HIGH: TAF CONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL.
M = MEDIUM: TAF HAS VARYING LEVEL OF CONSISTENCY WITH MODELS.
L = LOW: TAF INCONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL.
DATE SAT
UTC 1HRLY 00 01 02 03 04 05 06 07 08 09 10 11
EST 1HRLY 19 20 21 22 23 00 01 02 03 04 05 06
CRW CONSISTENCY H H H H H H H H H H H H
HTS CONSISTENCY H H H H H H H H H H H H
BKW CONSISTENCY H H H H H H H H H H H H
EKN CONSISTENCY M H H H H H H H L L L H
PKB CONSISTENCY H H H H H H H H H H H H
CKB CONSISTENCY M M M H H H H H H H H H
AFTER 00Z SUNDAY...
NO WIDESPREAD IFR CONDITIONS EXPECTED.
&&
.RLX WATCHES/WARNINGS/ADVISORIES...
WV...NONE.
OH...NONE.
KY...NONE.
VA...NONE.
&&
$$
SYNOPSIS...ARJ/JMV/30
NEAR TERM...30/26
SHORT TERM...JMV
LONG TERM...ARJ
AVIATION...26
AREA FORECAST DISCUSSION
NWS CHARLESTON WV
1249 AM EST THU JAN 3 2013
.SYNOPSIS...
HIGH PRESSURE CROSSES OVERNIGHT. CLIPPER LIKE SYSTEM PASSES THURSDAY
NIGHT. TWO UPPER SHORT WAVES PASS THIS WEEKEND...FOLLOWED BY HIGH
PRESSURE.
&&
.NEAR TERM /THROUGH TODAY/...
1230 AM UPDATE...
FCST ON TRACK.
630PM UPDATE...
OVERNIGHT LOWS CONTINUE TO BE THE TRICKY PART OF THE FORECAST.
SHOULD LOSE THE HIGH LEVEL CIRRUS TOWARDS THE END OF THE OVERNIGHT
FOR LOCATIONS UP TO THE MOUNTAINS...SO WILL DROP IN GOOD RADIATION
CONDITIONS. SREF PICKING UP ON STRATUS CLIPPING OUR EXTREME
NORTHWEST COUNTIES IN SOUTHEAST OHIO OVERNIGHT...AND LOW LEVEL
CLOUDS ON THE FAR EASTERN SLOPES IN POCAHONTAS COUNTY.
PREVIOUS DISCUSSION...
HEATING HAS ALLOWED STRATOCU TO FORM THIS AFTN...MOST PREVALENT
ACROSS SE OH AND N WV. LINGERING LLVL MOISTURE UNDER INVERSION
PROVIDING FOR A DREARY DAY ACROSS SW VA WITH LOW CIGS AND SOME
FOG. WILL ALLOW STRATOCU TO DISSIPATE WITH LOSS OF SUN AS CIRRUS
BLOW-OFF RIDING JET FROM SW INVADES TONIGHT. SOME CONCERN WITH LOW
STRATUS HANGING TOUGH ACROSS SE OH AND N WV PER RUC SOUNDINGS BUT
OTHER MDLS NOT REALLY SHOWING THIS. FOR TEMPS WILL HEDGE THAT CIRRUS
IS NOT OPAQUE ENOUGH TO HINDER FALL TOO MUCH. LOOKING AT TEENS
AND LWR 20S FOR MOST PART FOR OVERNIGHT LOWS.
DRY CONDITIONS PREVAIL TOMORROW WITH A MAINLY SUNNY SKY...SAVE
FOR PERHAPS PORTIONS OF SW VA TOWARD DICKENSON CO WHERE LOW CLOUDS
MAY LINGER THROUGH THE MORNING. HIGHS REBOUND SOME WITH EVERYONE
OUTSIDE OF HIGHER ELEVATIONS IN THE 30S. SOME CLDS MAY SNEAK INTO
SE OH TOWARD EVENING FROM AN APPROACHING CLIPPER TYPE FRONT.
&&
.SHORT TERM /TONIGHT THROUGH SATURDAY/...
VERY PROGRESSIVE AND DRY PATTERN THIS PERIOD. MODELS HAVE A MOISTURE
STARVED SHORT WAVE AND COLD FRONT IN THE NORTHERN STREAM DROPPING
RAPIDLY SOUTHEAST ACROSS THE OHIO VALLEY THURSDAY NIGHT AND EARLY
FRIDAY. A THERMAL TROUGH IN NORTHWEST FLOW BEHIND THE FRONT PROMPTS
SMALL POPS FOR SNOW SHOWERS MAINLY THURSDAY NIGHT...AND MOSTLY IN
THE MOUNTAINS...WITH LITTLE IF ANY ACCUMULATIONS. THEN...A QUIET
PERIOD WITH MODERATING TEMPERATURES LATER FRIDAY AND SATURDAY AS A
LOW AMPLITUDE UPPER RIDGE BUILDS OVER THE AREA. IT WILL BE JUST
AFTER THIS PERIOD BEFORE THE NEXT SYSTEM CAN AFFECT US. LOOK FOR
BELOW NORMAL TEMPS THURSDAY NIGHT AND FRIDAY BEHIND THE
FRONT...MODERATING CLOSE TO NORMAL ON SATURDAY.
&&
.LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/...
STRONG SHORT WAVE WILL MOVE ACROSS THE AREA SATURDAY NIGHT INTO
SUNDAY. BUFKIT SOUNDING CONTINUE TO INDICATE SATURATED SFC TO BARELY
BELOW MINUS 10C LEVEL...SUGGESTING GOOD CHANCES FOR LIGHT SNOW
FOLLOWED BY FREEZING DRIZZLE AS THE SYSTEM PULLS NORTHEAST.
NORTHWEST BACKWARDS TRAJECTORIES FROM SUNDAY RETURNS FROM IL AND
WI...BRINGING MUCH COLD AIR...CAPABLE TO SQUEEZE LOW LEVEL MOISTURE
INTO THE MOUNTAINS...TO PRODUCE LIGHT UPSLOPE SNOW OR FREEZING
DRIZZLE PER SHALLOWER MOISTURE IN THE COLUMN WITH NO LAKE CONNECTION
BELOW MINUS 10C. THEREFORE...KEPT POPS TO CHANCE FOR NOW ACROSS THE
NORTHERN HALF OF OUR CWA THROUGH SATURDAY NIGHT DIMINISHING BY EARLY
MONDAY.
TWEAKED HPC GUIDANCE FOR TEMPS THROUGH THE PERIOD...ACCOUNTING FOR
CLOUD COVER AND GFS H850 COLDER TEMPERATURES.
&&
.AVIATION /06Z THURSDAY THROUGH MONDAY/...
OTHER THAN SOME MVFR RIVER VALLEY MIST OVERNIGHT...VFR FCST AS HIGH
PRESSURE REIGNS. WEAK CLIPPER SYSTEM WILL INCREASE W FLOW SFC AND
ALOFT A BIT...AND BRING PATCHY STRATOCU LATE THU AND THU NT.
FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 06Z FRIDAY...
FORECAST CONFIDENCE: HIGH.
ALTERNATE SCENARIOS: MVFR RIVER VALLEY MIST MAY BE MORE OR LESS
PREVALENT THAN FCST OVERNIGHT.
EXPERIMENTAL TABLE OF FLIGHT CATEGORY OBJECTIVELY SHOWS CONSISTENCY
OF WFO FORECAST TO AVAILABLE MODEL INFORMATION:
H = HIGH: TAF CONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL.
M = MEDIUM: TAF HAS VARYING LEVEL OF CONSISTENCY WITH MODELS.
L = LOW: TAF INCONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL.
DATE THU 01/03/13
UTC 1HRLY 06 07 08 09 10 11 12 13 14 15 16 17
EST 1HRLY 01 02 03 04 05 06 07 08 09 10 11 12
CRW CONSISTENCY H H H H H H H H H H H H
HTS CONSISTENCY H H H H H H H H H H H H
BKW CONSISTENCY H H H H H H H H H H H H
EKN CONSISTENCY H H H H H H H H H H H H
PKB CONSISTENCY H H H H H H H H H H H H
CKB CONSISTENCY H H H H H H H H H H H H
AFTER 06Z FRIDAY...
NO WIDESPREAD IFR CONDITIONS EXPECTED.
&&
.RLX WATCHES/WARNINGS/ADVISORIES...
WV...NONE.
OH...NONE.
KY...NONE.
VA...NONE.
&&
$$
SYNOPSIS...ARJ/TRM/JMV/30
NEAR TERM...TRM/30/26
SHORT TERM...JMV
LONG TERM...ARJ
AVIATION...TRM
AREA FORECAST DISCUSSION FOR SOUTHEAST SD/SOUTHWEST MN/NORTHWEST IA
NWS SIOUX FALLS SD
1011 AM CST THU JAN 3 2013
.DISCUSSION.../ISSUED AT 1011 AM CST/
JUST ENOUGH ISENTROPIC LIFT IN THE 925-875 HPA LAYER THIS MORNING TO
COUPLE WITH VERY DENDRITIC TEMPERATURE RANGE TO KICK START SHALLOW
PRECIPITATION PROCESSES...AND BRING A LIGHT DUSTING TO SNOW TO THE
I29 CORRIDOR AND JUST EAST THROUGH MID MORNING. BAND IS ABOUT 40 NM
WIDE NEAR THE LEADING EDGE OF THE ADVANCING LOW CLOUDS /WITH DEPTH
NO MORE THAN 3000 FT PER MORNING ABR RAOB. FOR NOW...PROBABLY WILL
END UP WITH A TENTH OR TWO OF SNOWFALL AS BAND MOVES EAST...BUT
LIKELY TO NOT GET MEASURABLE LIQUID WITH THE VERY DENDRITIC SNOWFALL.
RAP IS REALLY THE ONLY RELIABLE SHORT RANGE GUIDANCE ON LOWER
CEILINGS...ALTHOUGH 12Z NAM LOOKS AS IF IT IS TRYING TO CATCH ON...
AND BOTH ARE FAIRLY PESSIMISTIC TO GET MUCH CLEARING TOWARD I29 BY
00Z. DID INCREASE CLOUDS AND ADD MENTION OF FLURRIES A COUPLE HOURS
AGO...BUT MAY END UP NEEDING TO DELAY CLEARING SOMEWHAT MORE. CLOUDS
WILL IMPACT POTENTIAL WARMING WEST...AND WILL LIKELY HELP THINGS
ALONG ACROSS THE COLDER EAST. /CHAPMAN
&&
.AVIATION.../FOR THE 18Z TAF ISSUANCE/
MASS OF MVFR CEILINGS WILL CONTINUE TO WORK EASTWARD THROUGH THE
DAY. LEADING 30-40NM FEATURING LIGHT SNOW AND FLURRIES...WITH SOME
VISIBILITIES BRIEFLY INTO THE IFR RANGE...BUT MOSTLY MVFR. SHOULD
BECOME VFR AGAIN AFTER 00Z TONIGHT FOR ALL TAF SITES. MVFR CEILINGS WEST
OF I29 WILL GRADUALLY BECOME VFR FROM THE WEST DURING THE AFTERNOON
HOURS. /CHAPMAN
&&
.PREV DISCUSSION.../ISSUED AT 300 AM CST/
TEMPERATURE AND CLOUD FORECAST A BIT TRICKY FOR TODAY. CURRENTLY
SEEING AN AREA OF CLEARING ACROSS THE EASTERN PORTION OF OUR
CWA...WITH A LARGE AREA OF STRATUS LOCATED OVER THE CENTRAL AND
WESTERN DAKOTAS. AS LOW LEVEL WINDS TURN MORE WESTERLY THINKING IS
THAT THIS STRATUS TO THE WEST WILL MOVE ACROSS OUR CWA...ONLY SLOWLY
DISSIPATING AS IT MOVES EAST. RAP SEEMS TO BE HANDLING THIS THE BEST
AND THUS FOLLOWED CLOSER TO IT FOR CLOUD COVER TODAY. SLOWED DOWN
THE EXIT OF THE CLOUDS...WITH CLEARING OUT WEST EXPECTED BY LATE
MORNING...THE INTERSTATE 29 CORRIDOR EARLY TO MID AFTERNOON...AND
NOT EXITING OUR EAST UNTIL LATE AFTERNOON OR EVENING. ALSO RAISED
HIGH TEMPERATURES TODAY BY A FEW DEGREES. TEMPERATURES UNDER THE
CURRENT STRATUS IN THE UPPER TEENS...AND AS IT MOVES BACK
IN...THINKING MOST LOCATIONS GET AT LEAST TO THESE TEMPERATURES.
WARMEST READINGS WILL BE WEST OF THE JAMES RIVER...WHERE AFTERNOON
SUN SHOULD ALLOW HIGHS IN THE MID 20S.
SHOULD SEE CLEAR SKIES BY TONIGHT. LOWS WILL BE TRICKY...AS A DECENT
LOW LEVEL JET MOVES ACROSS OUR EASTERN AREAS. OVERALL THINKING
SINGLE DIGITS AND TEENS FOR LOWS. THE WARMEST READINGS WILL BE NEAR
AND DOWNWIND OF THE BUFFALO RIDGE...WHERE SUSTAINED SOUTHWESTERLY
WINDS NEAR 20 KTS WILL KEEP THINGS MIXED. POTENTIAL EXISTS FOR LOWS
NEAR ZERO IN THE INTERSTATE 29 CORRIDOR IF WE CAN DECOUPLE. DID
TREND TOWARDS THE COOLER SIDE OF GUIDANCE HERE GIVEN SNOWCOVER AND
CLEAR SKIES...BUT IF THE WINDS STAY UP JUST ENOUGH THEN CURRENT LOWS
WILL LIKELY BE TOO COLD.
WILL SEE A BIT OF RIDGING AND WARMING TEMPERATURES ALOFT ON FRIDAY.
LOWERED HIGHS A BIT...GIVEN SNOW COVER AND EXPECTED WEAK MIXING
PREVENTING US FROM REALIZING MUCH OF THE WARM AIR ALOFT. ALTHOUGH
THE NAM SEEMS TOO COLD...AND THINKING WE STILL SEE UPPER 20S TO LOW
30S MOST SPOTS...WITH LOW 40S POSSIBLE IN OUR FAR SOUTHWEST. UPPER
LEVEL TROUGH AND ANOTHER COLD SHOT MOVES IN ON SATURDAY. LOOKS LIKE
WE SHOULD SEE SOME MORE STRATUS ON SATURDAY WITH THIS FEATURE. COULD
SEE SOME FLURRIES AS WELL...BUT NOT EXPECTING ANYTHING MORE THAN
THAT. MODELS DISAGREE SOME ON TIMING AND MAGNITUDE OF THE COLD
SHOT...BUT HIGHS WILL LIKELY BE IN THE 20S MOST SPOTS.
WE THEN SEE A WARMING TREND SUNDAY INTO THE MIDDLE OF NEXT WEEK AS
AN UPPER LEVEL RIDGE BUILDS IN. SUNDAY WILL STILL BE COOL ON THE
BACKSIDE OF THE TROUGH...WITH 20S EAST AND 30S SOUTHWEST. HOWEVER BY
MONDAY INTO WEDNESDAY...EXPECT WARMING TEMPERATURES ALOFT AND FLOW
FAVORABLE FOR DECENT MIXING. SO DESPITE SNOWCOVER...EXPECTING HIGHS
TO RISE ABOVE FREEZING IN MOST LOCATIONS EACH DAY UNDER PARTLY TO
MOSTLY SUNNY SKIES. MODELS IN GOOD AGREEMENT THAT A CUTOFF LOW OVER
SOUTHERN CALIFORNIA ON MONDAY WILL PUSH EAST INTO THE SOUTHERN
PLAINS BY MIDWEEK. AS IT IS PICKED UP BY THE UPPER FLOW AND TURNS
NORTHEAST DISAGREEMENT ENTERS ON HOW FAR NORTHWEST IT GETS. THERE IS
THUS THE POTENTIAL FOR SOME PRECIPITATION...PROBABLY WEDNESDAY NIGHT
OR THURSDAY WITH THIS SYSTEM...SO WILL HAVE TO MONITOR TRENDS. AS IT
LOOKS NOW...TEMPERATURE PROFILE MAY VERY WELL BE TOO WARM FOR
SNOW...FAVORING A RAIN OR MIXED PRECIP THREAT IF ANYTHING. FLOW THEN
TURNS FAVORABLE FOR MORE COLD AIR TO END NEXT WEEK. /CHENARD
&&
.FSD WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
MN...NONE.
IA...NONE.
NE...NONE.
&&
$$
AREA FORECAST DISCUSSION FOR SOUTHEAST SD/SOUTHWEST MN/NORTHWEST IA
NWS SIOUX FALLS SD
525 AM CST THU JAN 3 2013
.DISCUSSION.../ISSUED AT 300 AM CST/
TEMPERATURE AND CLOUD FORECAST A BIT TRICKY FOR TODAY. CURRENTLY
SEEING AN AREA OF CLEARING ACROSS THE EASTERN PORTION OF OUR
CWA...WITH A LARGE AREA OF STRATUS LOCATED OVER THE CENTRAL AND
WESTERN DAKOTAS. AS LOW LEVEL WINDS TURN MORE WESTERLY THINKING IS
THAT THIS STRATUS TO THE WEST WILL MOVE ACROSS OUR CWA...ONLY SLOWLY
DISSIPATING AS IT MOVES EAST. RAP SEEMS TO BE HANDLING THIS THE BEST
AND THUS FOLLOWED CLOSER TO IT FOR CLOUD COVER TODAY. SLOWED DOWN
THE EXIT OF THE CLOUDS...WITH CLEARING OUT WEST EXPECTED BY LATE
MORNING...THE INTERSTATE 29 CORRIDOR EARLY TO MID AFTERNOON...AND
NOT EXITING OUR EAST UNTIL LATE AFTERNOON OR EVENING. ALSO RAISED
HIGH TEMPERATURES TODAY BY A FEW DEGREES. TEMPERATURES UNDER THE
CURRENT STRATUS IN THE UPPER TEENS...AND AS IT MOVES BACK
IN...THINKING MOST LOCATIONS GET AT LEAST TO THESE TEMPERATURES.
WARMEST READINGS WILL BE WEST OF THE JAMES RIVER...WHERE AFTERNOON
SUN SHOULD ALLOW HIGHS IN THE MID 20S.
SHOULD SEE CLEAR SKIES BY TONIGHT. LOWS WILL BE TRICKY...AS A DECENT
LOW LEVEL JET MOVES ACROSS OUR EASTERN AREAS. OVERALL THINKING
SINGLE DIGITS AND TEENS FOR LOWS. THE WARMEST READINGS WILL BE NEAR
AND DOWNWIND OF THE BUFFALO RIDGE...WHERE SUSTAINED SOUTHWESTERLY
WINDS NEAR 20 KTS WILL KEEP THINGS MIXED. POTENTIAL EXISTS FOR LOWS
NEAR ZERO IN THE INTERSTATE 29 CORRIDOR IF WE CAN DECOUPLE. DID
TREND TOWARDS THE COOLER SIDE OF GUIDANCE HERE GIVEN SNOWCOVER AND
CLEAR SKIES...BUT IF THE WINDS STAY UP JUST ENOUGH THEN CURRENT LOWS
WILL LIKELY BE TOO COLD.
WILL SEE A BIT OF RIDGING AND WARMING TEMPERATURES ALOFT ON FRIDAY.
LOWERED HIGHS A BIT...GIVEN SNOW COVER AND EXPECTED WEAK MIXING
PREVENTING US FROM REALIZING MUCH OF THE WARM AIR ALOFT. ALTHOUGH
THE NAM SEEMS TOO COLD...AND THINKING WE STILL SEE UPPER 20S TO LOW
30S MOST SPOTS...WITH LOW 40S POSSIBLE IN OUR FAR SOUTHWEST. UPPER
LEVEL TROUGH AND ANOTHER COLD SHOT MOVES IN ON SATURDAY. LOOKS LIKE
WE SHOULD SEE SOME MORE STRATUS ON SATURDAY WITH THIS FEATURE. COULD
SEE SOME FLURRIES AS WELL...BUT NOT EXPECTING ANYTHING MORE THAN
THAT. MODELS DISAGREE SOME ON TIMING AND MAGNITUDE OF THE COLD
SHOT...BUT HIGHS WILL LIKELY BE IN THE 20S MOST SPOTS.
WE THEN SEE A WARMING TREND SUNDAY INTO THE MIDDLE OF NEXT WEEK AS
AN UPPER LEVEL RIDGE BUILDS IN. SUNDAY WILL STILL BE COOL ON THE
BACKSIDE OF THE TROUGH...WITH 20S EAST AND 30S SOUTHWEST. HOWEVER BY
MONDAY INTO WEDNESDAY...EXPECT WARMING TEMPERATURES ALOFT AND FLOW
FAVORABLE FOR DECENT MIXING. SO DESPITE SNOWCOVER...EXPECTING HIGHS
TO RISE ABOVE FREEZING IN MOST LOCATIONS EACH DAY UNDER PARTLY TO
MOSTLY SUNNY SKIES. MODELS IN GOOD AGREEMENT THAT A CUTOFF LOW OVER
SOUTHERN CALIFORNIA ON MONDAY WILL PUSH EAST INTO THE SOUTHERN
PLAINS BY MIDWEEK. AS IT IS PICKED UP BY THE UPPER FLOW AND TURNS
NORTHEAST DISAGREEMENT ENTERS ON HOW FAR NORTHWEST IT GETS. THERE IS
THUS THE POTENTIAL FOR SOME PRECIPITATION...PROBABLY WEDNESDAY NIGHT
OR THURSDAY WITH THIS SYSTEM...SO WILL HAVE TO MONITOR TRENDS. AS IT
LOOKS NOW...TEMPERATURE PROFILE MAY VERY WELL BE TOO WARM FOR
SNOW...FAVORING A RAIN OR MIXED PRECIP THREAT IF ANYTHING. FLOW THEN
TURNS FAVORABLE FOR MORE COLD AIR TO END NEXT WEEK. /CHENARD
&&
.AVIATION.../FOR THE 12Z TAF ISSUANCE/
VFR CONDITIONS ALONG AND EAST OF I29 WILL BECOME MVFR CEILINGS
DURING THE MORNING...AND THEN PERSIST THROUGH THE AFTERNOON...AND
THEN BECOME VFR AGAIN AFTER 00Z TONIGHT. MVFR CEILINGS WEST OF I29
WILL GRADUALLY BECOME VFR FROM THE WEST DURING THE AFTERNOON HOURS.
&&
.FSD WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
MN...NONE.
IA...NONE.
NE...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS HOUSTON/GALVESTON TX
915 PM CST FRI JAN 4 2013
.UPDATE...
SCATTERED OFFSHORE SHOWERS BECOMING BETTER ORGANIZED JUST OFF THE
COASTLINE...WITH VERY LIGHT SHOWER ACTIVITY JUST TO THE WEST OF
OUR NORTHWESTERN CWA. WEAK DIVERGENCE RIDING PARALLEL THE COAST
(PER REGION FALLING IN THE RR 25H QUAD) AND THE OFFSHORE STATIONARY
BOUNDARY WILL BE ENOUGH TO KEEP PERIODIC LIGHT SHOWERS IN PLAY
THROUGH SATURDAY AFTERNOON. THE NEAR WEST-TO-EAST ELONGATED UPPER
TOUGH AXIS WILL EVENTUALLY PASS EAST OF THE REGION LATE TOMORROW...
BRINGING THE INTERIOR SHRA TO AN END GOING INTO SATURDAY EVENING.
A WEAK LOWER LEVEL BOUNDARY WILL PASS INTO CENTRAL TEXAS...BUT
WITHOUT A SIGNIFICANT NORTHWESTERN HIGH TO BACK IT...THIS BOUNDARY
WILL STRETCH OUT AND SURFACE WINDS WILL REMAIN NORTHEAST IN NATURE.
MODERATE TO STRONG NORTH-EAST MARITIME WINDS THROUGH THE WEEKEND
AS THE OFFSHORE GRADIENT BETWEEN INLAND HIGH PRESSURE AND THE OFFSHORE
STATIONARY BOUNDARY STAYS TAUNT.
ALONG WITH PASSING SHOWERS...A COLD AND CLOUDY SATURDAY. ISENTROPIC
UPGLIDE IN PLACE AS MID-LEVEL SOUTHWESTERLIES ABOVE THESE NEAR SURFACE
(NORTH)EASTERLIES WILL KEEP SKIES MOSTLY OVERCAST AND THE MAJORITY
OF THE DAY IN THE 40S...MERCURY ONLY BRIEFLY TOUCHING THE LOWER 50S
FOR A LATE AFTERNOON HOUR OR TWO. 31
&&
.PREV DISCUSSION... /ISSUED 607 PM CST FRI JAN 4 2013/
DISCUSSION...
UPDATED AVIATION DISCUSSION.
AVIATION...
LATEST OBS AND RADAR SHOWING SOME LIGHT SHOWERS AROUND NORTHERN
TAF SITES WITH VFR 5000 TO 6000 FOOT DECK EVERYWHERE. SOME LOWER
CLOUDS INDICATED OFF TO THE WEST. OVERALL EXPECTING MOSTLY VFR
CONDITIONS AT TAF SITES...WITH A PERIOD OF MVFR POSSIBLE AT LEAST
NORTHERN TAF SITES OVERNIGHT AS BAND OF LIGHT RAIN SHIFTS EAST.
ANOTHER BAND OF LIGHT RAIN POSSIBLE ON SATURDAY FARTHER SOUTH AS
JET STREAK PIVOTS AROUND UPPER LOW...PLACING SE TEXAS IN RIGHT
REAR QUADRANT. IN ANY CASE NOT EXPECTING MUCH IN THE WAY OF
VISIBILITY RESTRICTIONS...JUST A SHORT PERIOD OF MVFR CIGS WITH
THESE BANDS OF RAIN AS THEY PIVOT THROUGH. 46
&&
PREV DISCUSSION... /ISSUED 407 PM CST FRI JAN 4 2013/
DISCUSSION...
NOT TOO MANY CHANGES FOR THE SHORT TERM PART OF THE FCST WITH THIS
PACKAGE AS THE COLD/CLOUDY/WET PATTERN REMAINS IN PLACE OVER SE TX
THROUGH THE EARLY PART OF THIS WEEKEND. STRONG SOUTHERN STREAM JET
HELPING TO BRING A SERIES OF SHORTWAVES ACROSS THE REGION WITH THE
NEXT ONE LOOKING LIKE IT IS GOING TO MOVE THROUGH OUR CWA LATE TO-
NIGHT/SAT (PER LATEST THE WV LOOPS).
THE PERSISTENT BKN/OVC MID/HIGH CLOUD DECK SHOULD BREAK BY SUN AS
THE MAIN UPPER TROF AXIS SHIFTS EAST AND THE BRIEF RIDGING DEVEL-
OPS IN ITS WAKE. BUT AS IT HAS BEEN THE TREND OF LATE...THIS VERY
PROGRESSIVE UPPER PATTERN WILL BE BRINGING THE NEXT SYSTEM TOWARD
THE STATE QUICKLY. WHILE MODELS HAVE BEEN CONSISTENT WE ARE STILL
SEEING MARKED DIFFERENCES IN REGARD TO THE TIMING FOR THE PASSAGE
OF THE NEXT CLOSED UPPER LOW STORM SYSTEM. ECMWF RETAINING A LONE
WOLF ROLE WITH ITS SLOWER TIMING...WITH THE GFS APPEARING TO HAVE
SPED UP WITH THE 12Z RUNS. DID MAKE SOME CHANGES TO POPS FOR THIS
TUES/TUES NIGHT TIMEFRAME ACCOUNT FOR THE UNCERTAINTY. REGARDLESS
WE COULD BE DEALING WITH STRONG/SEVERE STORMS WITH THE PASSAGE OF
THIS SYSTEM (NO MATTER WHICH DAY IT ARRIVES). PROGS OF STRONG LOW
TO MID LEVEL INFLOW (40-50KTS)...FAVOURABLE POSITION OF THE UPPER
JET (LFQ) AND THE PASSAGE OF THE COLD FRONT ITSELF ALL SEEM TO BE
POINTING IN THAT DIRECTION. BEAR WATCH IN PLACE. 41
&&
.PRELIMINARY POINT TEMPS/POPS...
COLLEGE STATION (CLL) 40 51 38 57 35 / 30 20 10 10 10
HOUSTON (IAH) 40 52 39 60 39 / 30 40 10 10 10
GALVESTON (GLS) 45 54 46 59 47 / 30 40 20 10 10
&&
.HGX WATCHES/WARNINGS/ADVISORIES...
TX...NONE.
GM...SMALL CRAFT SHOULD EXERCISE CAUTION THROUGH SATURDAY AFTERNOON
FOR THE FOLLOWING ZONES: WATERS FROM FREEPORT TO THE
MATAGORDA SHIP CHANNEL OUT 20 NM...WATERS FROM HIGH ISLAND
TO FREEPORT OUT 20 NM.
SMALL CRAFT ADVISORY UNTIL 5 PM CST SATURDAY FOR THE FOLLOWING
ZONES: WATERS FROM FREEPORT TO THE MATAGORDA SHIP CHANNEL
20 NM TO 60 NM...WATERS FROM HIGH ISLAND TO FREEPORT 20 TO
60 NM.
&&
$$
DISCUSSION...31/46
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
541 PM CST FRI JAN 4 2013
.SHORT TERM...TONIGHT THROUGH MONDAY
233 PM CST FRI JAN 4 2013
MAIN FORECAST CONCERNS ARE ON LIGHT PRECIPITATION CHANCES SATURDAY
AFTERNOON INTO SATURDAY NIGHT.
CURRENTLY AS OF 20Z...WATER VAPOR LOOP AND RAP 500MB HEIGHT ANALYSIS
SHOWED RIDGING ALONG THE WEST COAST OF THE U.S. INTO BRITISH
COLUMBIA...AN UPPER LOW OVER NEW MEXICO...A SHORTWAVE TROUGH OVER
SOUTHERN ALBERTA...WEAK RIDGING OVER THE DAKOTAS AND DEEP TROUGHING
OVER EASTERN CANADA. THE FORECAST AREA WAS UNDER SUBSIDENCE ALOFT
BEING IN NORTHWEST FLOW AHEAD OF THE DAKOTAS RIDGING...RESULTING IN
CLEAR SKIES. IN FACT...MAINLY CLEAR SKIES ENCOMPASS MUCH OF THE
UPPER MIDWEST DUE TO PLENTY OF DRY AIR...SEEN ON 12Z SOUNDINGS FROM
BIS...OAX...MPX AND GRB. ONE THING OF INTEREST ON ALL OF THOSE
SOUNDINGS IS A STRONG AND NEARLY SATURATED INVERSION BETWEEN
925-950MB. AGAIN...DESPITE THE NEAR SATURATION...SKIES ARE STILL
CLEAR. SUNSHINE PLUS THE 925MB TEMPS STARTING OFF IN THE -3 TO -6C
RANGE AT 12Z FROM SOUNDING DATA AND DRY AIR HAS ALLOWED TEMPERATURES
TO CLIMB INTO THE MID 20S TO LOW 30S. TO THE NORTHWEST...HIGH
CLOUDS WERE SPREADING ACROSS SASKATCHEWAN AND NORTH DAKOTA AHEAD
OF THE SOUTHERN ALBERTA SHORTWAVE TROUGH. IN ADDITION...AN AREA OF
LOW PRESSURE HAS FORMED OVER SOUTHERN SASKATCHEWAN WITH A WARM
FRONT EXTENDING SOUTHEAST TO BISMARCK NORTH DAKOTA.
TONIGHT AND SATURDAY...MODELS ARE IN GOOD AGREEMENT DROPPING THE
SHORTWAVE TROUGH OVER ALBERTA THROUGH THE NORTHERN PLAINS AND INTO
NEBRASKA BY 00Z SUNDAY. THIS TROUGH HELPS TO EJECT AND SHEAR OUT THE
NEW MEXICO UPPER LOW...WHICH GETS LIFTED INTO SOUTHERN ILLINOIS AND
INDIANA. THE TRACKS OF THESE FEATURES SPLIT THE FORECAST AREA...
HOWEVER...THERE ARE STILL CONCERNS. THE MAIN ONE IS WITH LOW LEVEL
SATURATION. 925-900MB RH PROGS FROM THE 04.12Z NAM/GFS SHOW THAT AS
THE NEW MEXICO UPPER LOW LIFTS NORTHEAST...AN AREA OF LOW STRATUS
FORMS ACROSS MISSOURI SATURDAY MORNING...WHICH THEN SPREADS INTO
EASTERN IOWA AND SOUTHERN WISCONSIN DURING THE AFTERNOON. ABOVE
900MB...TROPOSPHERE IS STILL PRETTY DRY. ANALYSIS LOOKING AT THE
275-280K SURFACES SHOWS THAT MOISTURE GETS PULLED UP OUT OF THE GULF
OF MEXICO AS THE NEW MEXICO UPPER LOW LIFTS NORTHEAST. IN
ADDITION...THERE IS WEAK LIFT ON THESE SURFACES...WHICH GIVEN THAT
THE TEMPERATURE PROFILE HAS NO ICE...COULD LEAD TO FREEZING DRIZZLE
FORMATION. AS SUCH...HAVE RETAINED A MENTION OF FREEZING DRIZZLE
FROM 21-00Z...BUT RESTRICTED IT TO THE SOUTHEAST 1/3 OF THE AREA TO
CORRELATE WITH THE LIFT ON THE 275-280K SURFACES. ELSEWHERE...DRY
CONDITIONS WILL PREVAIL WITH PERHAPS LITTLE IN THE WAY OF CLOUD
COVER UNTIL LATER SATURDAY. WITH CLEAR SKIES AND DRY AIR TONIGHT...
ALONG WITH LIGHT WINDS IN MOST LOCATIONS EXCEPT FOR SOUTHEAST
MINNESOTA...TEMPERATURES COULD REALLY TANK TONIGHT. WENT SLIGHTLY
BELOW GUIDANCE FOR THE TYPICAL COLD SPOTS AS THINK THEY SHOULD BE
ABLE TO COME CLOSE TO ZERO. SINGLE DIGITS LOOK LIKELY ELSEWHERE.
925MB TEMPS ARE FAIRLY SIMILAR TO TODAY FOR SATURDAY...AND WITH
PLENTY OF SUN...HIGHS SHOULD TOP OUT CLOSE TO THOSE TODAY.
SATURDAY NIGHT AND SUNDAY...MODELS SHOW ANOTHER SHORTWAVE COMING OUT
OF SOUTH CENTRAL CANADA LATE SATURDAY...DROPPING SOUTHEAST INTO
WESTERN ILLINOIS BY 18Z SUNDAY. THIS SHORTWAVE WILL HELP TO KICK THE
TROUGH DROPPING INTO NEBRASKA EASTWARD...BUT ALSO BRING WITH IT A
SURGE OF DRY...COLDER AIR. BY 18Z SUNDAY...925MB TEMPS OVER THE
FORECAST AREA ARE AROUND -8C. PRIOR TO THE COLD AIR ARRIVAL...THERE
IS A CONCERN TO DEAL WITH WHICH IS THE SAME AS SATURDAY...LOW
STRATUS AND ANY LIGHT PRECIPITATION POSSIBLE WITH IT. IN THIS
CASE...MODELS HAVE AN AREA OF STRATUS COMING INTO THE FORECAST AREA
BEHIND A COLD FRONT ASSOCIATED WITH THE NEBRASKA TROUGH. VERY LITTLE
IF ANY ISENTROPIC LIFT IS NOTED WITHIN THIS STRATUS...SO THINK ANY
LIGHT PRECIPITATION POTENTIAL WOULD REMAIN OVER THE SOUTHEAST THIRD
OF THE AREA EARLY IN THE EVENING AHEAD OF THE FRONT. AGAIN...THIS IS
LIKELY TO BE FREEZING DRIZZLE GIVEN LACK OF ICE IN THE CLOUD. AFTER
MIDNIGHT...THERE ARE INDICATIONS OF A SECONDARY TROUGH WHICH IN
925MB TEMPS ALMOST LOOKS LIKE A WARM FRONT DROPPING SOUTH THROUGH
WISCONSIN. 270-275K ISENTROPIC LIFT PLOTS SHOW SOME LOW LEVEL LIFT
WITH THIS...LIKELY ENOUGH TO PRODUCE LIGHT PRECIPITATION. IT APPEARS
ICE WILL EXIST IN THE CLOUD THIS TIME...AIDED TOO BY MID CLOUDS
DROPPING SOUTH WITH THE SHORTWAVE COMING OUT OF SOUTH CENTRAL
CANADA. THUS...HAVE MAINTAINED A FLURRY MENTION. DRYING AND CLEARING
WILL TAKE PLACE SUNDAY MORNING FROM NORTHWEST TO SOUTHEAST. THE
INCREASE OF CLOUDS AND COLD ADVECTION WILL COUNTER-ACT EACH OTHER
SATURDAY NIGHT FOR LOWS...AND HAVE WENT WITH A BLEND OF GUIDANCE
SUGGESTING TEMPERATURES DROPPING INTO THE TEENS. SLIGHTLY COLDER DAY
EXPECTED ON SUNDAY GIVEN THE AFOREMENTIONED 925MB TEMPS.
SUNDAY NIGHT AND MONDAY...ATTENTION TURNS TO DEEP TROUGHING JUST OFF
THE WEST COAST OF NORTH AMERICA. OTHER THAN THE 04.12Z NAM...ALL
OTHER MODELS DEPICT THE TROUGH PROGRESSING EASTWARD INTO THE WESTERN
U.S. THROUGH THE WEEKEND AND SPLITTING INTO TWO. THE SOUTHERN
PART FORMS INTO A CUT-OFF LOW WHICH GETS STUCK IN THE SOUTHWESTERN
U.S.. THE NORTHERN PART IS A TROUGH THAT TRACKS ALONG THE
U.S./CANADIAN BORDER...BRINGING WITH IT A DYING COLD FRONT INTO
WESTERN MINNESOTA ON MONDAY. REGARDING THAT 04.12Z NAM...THE MODEL
HAS BEEN DISCOUNTED AS AN OUTLIER AS IT KEEPS A FULL SCALE TROUGH
AND MARCHES IT EASTWARD INTO THE PLAINS BY 00Z TUESDAY. NO MATTER
WHAT MODEL SOLUTION IS FOLLOWED...THIS PERIOD ENDS UP DRY WITH WARM
ADVECTION THROUGHOUT AS LOW LEVEL SOUTHWEST WINDS INCREASE AHEAD OF
THE APPROACHING SPLIT TROUGH AND DYING SURFACE COLD FRONT. 925MB
TEMPS CLIMB TO -2 TO -4C BY 18Z MONDAY WHILE 850MB TEMPS JUMP TO +2
TO +4C. THUS...MONDAY SHOULD END UP MUCH WARMER THAN SUNDAY WITH
MOST LOCATIONS TOPPING OUT FROM THE UPPER 20S TO MID 30S PER ECMWF
GUIDANCE. COLDEST LOCATIONS EXPECTED OVER SOUTHEAST MINNESOTA AND
NORTHEAST IOWA WITH HIGHER ALBEDO FROM SNOWPACK. LOWS SUNDAY NIGHT
LIKELY IN THE EVENING BEFORE SOUTHWEST WINDS PICK UP. FOLLOWED BLEND
OF GUIDANCE FOR LOWS.
.LONG TERM...MONDAY NIGHT THROUGH FRIDAY
233 PM CST FRI JAN 4 2013
FOCUS AS HAS BEEN THE PAST FEW DAYS IS ON THE UPPER LOW IN THE
SOUTHWESTERN U.S. ON MONDAY. YET AGAIN THERE IS A SPLIT IN SCENARIOS
AMONGST MODEL HANDLING OF THIS UPPER LOW:
1. THE 04.12Z CANADIAN REPRESENTS A VERY FAST SCENARIO...LIFTING IT
NORTHEAST ACROSS CHICAGO TUESDAY NIGHT. WE WOULD END UP WITH A LIGHT
TO MODERATE SNOWFALL ACROSS THE FORECAST AREA TUESDAY INTO TUESDAY
NIGHT SHOULD THIS VERIFY.
2. NEXT BEHIND THE CANADIAN IS THE 04.12Z GFS...LIFTING IT FROM
TEXAS ON TUESDAY INTO THE OHIO VALLEY ON WEDNESDAY. THIS SCENARIO
WOULD IT PAN OUT WOULD KEEP THE AREA DRY AND TEMPERATURES ABOVE
NORMAL THROUGH THURSDAY.
3. LASTLY...THE 04.12Z ECMWF/UKMET ARE EXTREMELY CONSISTENT WITH
PAST ECMWF RUNS...HAVING THE UPPER LOW CROSS NORTHERN MEXICO ON
TUESDAY...SHIFTING INTO TEXAS ON WEDNESDAY...THEN LIFTING INTO
ILLINOIS ON THURSDAY. THIS SCENARIO WOULD YIELD ABOVE NORMAL
TEMPERATURES THROUGH THURSDAY...WITH DRY WEATHER THROUGH WEDNESDAY
EVENING...RAIN TO MUCH OF THE AREA FOR LATE WEDNESDAY NIGHT INTO
THURSDAY...THEN TAPERING OFF TO A SNOW OR RAIN/SNOW MIX THURSDAY
NIGHT.
THE WHOLE PROBLEM RESULTING IN THE VARIOUS SCENARIOS STARTS ON
SUNDAY...REGARDING HOW QUICK THE DEEP UPPER TROUGH SPLITS INTO TWO
AND HOW FAST UPPER RIDGING CAN BUILD INTO THE PACIFIC NORTHWEST
BEHIND IT. PER HPC AND WANTING TO FOLLOW THE CONSISTENT AND GOOD
EXTENDED VERIFYING ECMWF...LEANED THE LONG TERM FORECAST MORE
TOWARDS THE ECMWF SOLUTION. THIS ALSO IS IN BETTER AGREEMENT WITH
THE PREVIOUS FORECAST. STILL HAVE ENDED UP KEEPING A SNOW OR
RAIN/SNOW MIX IN FOR WEDNESDAY NIGHT INTO THURSDAY MORNING...TO
HANDLE UNCERTAINTY ON THE TEMPERATURE RISE AND NOT WANTING TO
INTRODUCE FREEZING RAIN SINCE THAT TYPE SEEMS UNLIKELY.
AFTER THURSDAY...NEW DEEP TROUGHING IS FORECAST TO FORM BY ALL
MODELS OVER THE WESTERN U.S....WHICH IS ONE OF THE FEATURES THAT
HELPS KICK OUT THE UPPER LOW IN THE ECMWF/UKMET. SHORTWAVES EJECTING
OUT OF THE TROUGH REQUIRE CHANCES OF SNOW IN FOR FRIDAY. COOLER
TEMPERATURES ARE LIKELY AS WELL...THOUGH AT LEAST FOR FRIDAY STILL
CLOSE TO NORMAL AS THE DEEPER COLDER AIR ASSOCIATED WITH THE TROUGH
HOLDS OFF UNTIL THE WEEKEND.
&&
.AVIATION...TONIGHT AND SATURDAY
541 PM CST FRI JAN 4 2013
CLEAR SKIES AND LIGHT SOUTH-SOUTHWEST WINDS WILL BE THE RULE
TONIGHT AS A RIDGE AXIS OF HIGH PRESSURE MOVES INTO THE REGION.
SOME MODEL GUIDANCE IS SUGGESTING THAT SOME FOG/LOW CEILINGS MAY
DEVELOP FROM NORTH DAKOTAS THROUGH CENTRAL MINNESOTA AND NORTHERN
WISCONSIN...BUT THESE MODELS APPEAR TO BE OVERDOING THE AMOUNT OF
LOW LEVEL MOISTURE AVAILABLE TO CREATE THE FOG. WILL HAVE TO
MONITOR FOR TRENDS ON THIS OVERNIGHT.
OTHERWISE...UPPER LEVEL CLOUD COVER WILL BE ON THE INCREASE
TOMORROW MORNING AS A SYSTEM CURRENTLY IN THE SOUTHERN PLAINS
LIFTS TO THE NORTHEAST THROUGH THE MID MISSISSIPPI RIVER VALLEY.
CLOUD COVER WILL CONTINUE TO INCREASE INTO THE AFTERNOON AS THIS
SYSTEM CLOSES IN ON NORTHERN ILLINOIS...BUT IT APPEARS THAT THE
BETTER LOW LEVEL MOISTURE MAY STAY SOUTH INITIALLY. GOING INTO
TOMORROW EVENING AND OVERNIGHT APPEARS TO BE A BETTER CHANCE FOR
SOME LOWER CEILINGS/VIS...SO HAVE LEFT THE FORECAST VFR THROUGH
THE AFTERNOON AT THIS TIME.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
233 PM CST FRI JAN 4 2013
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...AJ
LONG TERM...AJ
AVIATION...HALBACH
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
233 PM CST THU JAN 3 2013
.SHORT TERM...
233 PM CST THU JAN 3 2013
MAIN CONCERN IN THE SHORT TERM IS THE CLOUD TRENDS TONIGHT...AND
THEN ATTENTION SHIFTS TO CLOUDS AND FLURRIES/DRIZZLE ON SATURDAY.
19Z SURFACE ANALYSIS SHOWS RIDGE OF HIGH PRESSURE RUNNING FROM KS
UP INTO MN...AS LOW PRESSURE EXITS ACROSS THE GREAT LAKES REGION.
SATELLITE IMAGERY SHOWS EXTENSIVE LOW CLOUDS ACROSS MUCH OF THE
AREA...BUT CLOUD IS DISSIPATING ON THE WESTERN EDGE. BACK EDGE OF
THE CLOUD BAND HAD REACHED THE MISSISSIPPI RIVER...WITH ANOTHER
DIMINISHING PATCH OF CLOUDS ALONG THE MN/DAKOTAS BORDER. WHERE
THERE WERE CLOUDS...THERE WERE ALSO FLURRIES.
FIRST ISSUE IS THE CLOUD TRENDS TONIGHT. WITH RIDGING MOVING
IN...ANTICIPATE THE CLOUDS WILL CONTINUE TO DISSIPATE TONIGHT...
WHICH IS IN LINE WITH PREVIOUS FORECAST THINKING. WITH LITTLE
CLOUD AND DIMINISHING WINDS UNDER THE RIDGE...THINK IT IS PRUDENT
TO CONTINUE WITH TEMPERATURES AT OR BELOW GUIDANCE. WINDS WILL
COME AROUND TO THE SOUTH LATE IN THE NIGHT...BUT NOT SURE IT WILL
OCCUR FAST ENOUGH TO LIMIT A TEMP PLUNGE...ESPECIALLY OVER THE
FAVORED COOL SPOTS IN WESTERN WI.
GOOD LOW LEVEL WARM ADVECTION CONTINUES ACROSS THE AREA FOR
FRIDAY. WITH DRY AIR IN PLACE AND AMPLE SUNSHINE...ALONG WITH
A WARM SOUTHWEST BREEZE...HIGHS SHOULD WARM WELL INTO THE 20S AND
LOWER 30S. BUT THE DRY AIR WILL ALSO AID RADIATIONAL COOLING
FRIDAY NIGHT...SO EXPECT ANOTHER CHILLY NIGHT.
NEXT TAG-TEAM OF DISTURBANCES LOOKS TO PROVIDE A CHANCE FOR SOME
LIGHT PRECIPITATION STARTING LATE SATURDAY. ONE TROUGH WILL MOVE
THROUGH THE SOUTHERN PLAINS AND WILL TAKE A TURN UP TOWARD CHICAGO
BY MID-DAY ON SATURDAY. MEANWHILE...A SECOND SHORT WAVE TROUGH IN
THE NORTHERN STREAM WILL DROP FROM THE DAKOTAS INTO MN. EACH WILL
PROVIDE SOME LIFT AND SUPPORT FOR PRECIPITATION...HOWEVER DEEPER
MOISTURE WILL BE LACKING. PERUSAL OF VARIOUS MODEL SOUNDINGS VIA
BUFKIT SHOWS THE MOISTURE TO BE VERY SHALLOW...AND THE TEMPERATURE
PROFILE SUGGESTS MUCH OF THE LOWER COLUMN WHERE SATURATION OCCURS
WILL BE RELATIVELY WARM...NEAR OR ABOVE -10C. THERE IS SOME
INDICATION ON A FEW MODELS THAT SOME SEEING OF THIS LAYER COULD
OCCUR FROM ABOVE. EITHER WAY...LIFT IS LIMITED AND AMOUNTS WILL
BE VERY LIGHT. DISCUSSION WITH SURROUNDING OFFICES LED TO
REINTRODUCING FLURRIES TO THE FORECAST...BUT OPTED NOT TO ADD
THE DRIZZLE WORDING AT THIS TIME.
.LONG TERM...
233 PM CST THU JAN 3 2013
MEDIUM RANGE PERIOD CONTINUES TO BE MUDDLED AS MODEL SOLUTIONS ARE
IN TWO DISTINCT CAMPS REGARDING THE ENERGY DIGGING INTO THE WEST
COAST IN BOTH THE SOUTHERN AND NORTHERN STREAMS. IF ANYTHING...THE
12Z MODEL SOLUTIONS HAVE ADDED MORE UNCERTAINTY. ONE CLUSTER OF
MODELS...INCLUDING THE GFS/GEM/UKMET SUPPORT A STRONG BUT PROGRESSIVE
LONG WAVE TROUGH MOVING ACROSS THE CONUS EARLY NEXT WEEK...WHILE
THE NAM AND VARIOUS ENSEMBLES SUPPORT THE ECMWF WITH A CLOSED
CIRCULATION DEVELOPING OVER NORTHWEST MEXICO AND MOVING SLOWLY INTO
THE CENTRAL PLAINS BY THURSDAY. ECMWF HAS A BETTER LONG-RANGE
TRACK RECORD SO IT IS HARD TO DISCOUNT ITS SOLUTION. HOWEVER...
WITH THE AMOUNT OF ENERGY SEEN MOVING INTO THE TROUGH OVER THE
WEEKEND...IT MAY BE HARD FOR THE SYSTEM TO ACTUALLY SEPARATE
ITSELF FROM THE FLOW AS DEPICTED. FOR NOW HAVE CONTINUED ALONG THE
LINE OF THE PREVIOUS FORECAST...WHICH LINES UP CLOSER TO THE
ECMWF. THIS SYSTEM WILL HAVE TO BE MONITORED...BECAUSE DEPENDING
ON THE TRACK AND TEMPERATURE PROFILES...SOMEBODY IN OUR REGION
WILL SEE SIGNIFICANT PRECIPITATION...AND IT COULD BE SNOW OR EVEN
RAIN. CONFIDENCE IN THIS PERIOD OF THE FORECAST IS BELOW AVERAGE.
EITHER WAY...IT APPEARS THE OVERALL FLOW REGIME WILL BECOME MORE
WESTERLY AND THEN SOUTHWESTERLY...WHICH SHOULD PROVIDE A WARM UP.
TEMPERATURES LOOK TO BE ABOVE NORMAL NEXT WEEK.
&&
.AVIATION...THROUGH 18Z FRIDAY
1113 AM CST THU JAN 3 2013
WEAK SURFACE RIDGE CENTERED OVER NEBRASKA WITH THE RIDGE AXIS
NORTH INTO MINNESOTA. MVFR CLOUDS EAST OF THE RIDGE AXIS ARE MOVING
SLOWLY TO THE SOUTHEAST AND ARE EXPECTED TO CLEAR BOTH TAF SITES
LATE THIS AFTERNOON. WILL SEE THE FLURRIES CONTINUE UNTIL THE
CLOUDS CLEAR THE AREA AS THE 03.15Z RAP SOUNDINGS SHOW SOME WEAK
OMEGA THROUGH THE SATURATED LAYER. ONCE THE CLOUDS CLEAR OUT...VFR
CONDITIONS WITH CLEAR SKIES EXPECTED FOR THE REMAINDER OF THE
PERIOD. THE CENTER OF THE SURFACE RIDGE WILL MOVE INTO KANSAS AND
OKLAHOMA TONIGHT AND ONCE THE RIDGE AXIS MOVES THROUGH...THE AREA
WILL BE IN THE PRESSURE GRADIENT FROM A SYSTEM PASSING ACROSS
SOUTHERN CANADA. THIS WILL BE ENOUGH TO KEEP THE WINDS UP AROUND
10 KNOTS OUT OF THE SOUTHWEST.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
233 PM CST THU JAN 3 2013
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...MW
LONG TERM...MW
AVIATION...04
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
1113 AM CST THU JAN 3 2013
.SHORT TERM...TODAY THROUGH SATURDAY NIGHT
341 AM CST THU JAN 3 2013
MAIN FORECAST CONCERNS THIS PACKAGE...SMALL PRECIP/FLURRY/FZDZ
CHANCES THIS MORNING AND AGAIN SAT NIGHT...TEMPERATURES THRU
THE PERIOD.
06Z DATA ANALYSIS HAD A BROAD AREA OF LOW PRESSURE ACROSS THE
REGION...CENTERED OVER LK SUPERIOR. LEAD TROUGH/WIND SHIFT AROUND
THIS LOW WAS OVER EASTERN WI TO EASTERN IA. SECOND TROUGH/FRONT WAS
OVER NORTHWEST WI TO NEAR OMAHA. LEAD BAND OF VERY LIGHT SNOW WITH
THE FIRST TROUGH WAS EXITING THE FCST AREA. MORE -SN WITH THE SECOND
TROUGH/FRONT AND A SHORTWAVE DROPPING SOUTH ACROSS MN WAS ROTATING
THRU EAST CENTRAL AND NORTHEAST MN TOWARD THE FCST AREA. PATCHY
-FZDZ HAD BEEN REPORTED MIXED WITH THE -SN IN THE FCST AREA...BUT IR
CLOUD TOP TEMPS INDICATE ICE SEEDING SHOULD BE OCCURRING IN THE
CLOUD TOPS. UPSTREAM...-SN REPORTED WITH THE PRECIP MOVING THRU THE
KMSP/KSTP AREA. TEMPS ON THE MILD SIDE FOR EARLY JAN AND NEAR/AT
24HR HIGHS ACROSS MUCH OF THE FCST AREA EARLY THIS MORNING.
03.00Z MODELS INITIALIZED WELL AND AGAIN OFFER VERY SIMILAR
SOLUTIONS THRU THE SHORT-TERM PERIOD. THIS WITH A MODERATELY ACTIVE
NORTHWEST FLOW AND SHORTWAVE TROUGHS EITHER EXITING OR MOVING INTO
THE REGION THRU SAT NIGHT. DPROG/DT OF 500MB HGTS AT 03.00Z
INDICATED THE MODEL RUNS OF OF 01.00Z AND 02.00Z VERIFIED VERY WELL
ACROSS NOAM BUT ALL WERE BIT FAST WITH THE NEXT SHORTWAVE TROUGH/LOW
HEADED FOR THE OR/WA COAST. MODELS OFFER A TIGHT CONSENSUS TODAY/
TONIGHT AS ONE TROUGH EXITS AND HGTS QUICKLY RISE IN ITS WAKE.
TIGHTER CONSENSUS CONTINUE FRI/FRI NIGHT AS THE NEXT SHORTWAVE
TROUGH DROPS INTO THE NORTHERN PLAINS BUT TREND FAVORS SLOWER OF THE
EARLIER RUNS WITH THIS FEATURE AT 12Z SAT. CONSENSUS LOOSENS SAT/SAT
NIGHT AS THIS TROUGH MOVES ACROSS THE UPPER MIDWEST...BUT TRENDING
TOWARD A COMPROMISE OF THE EARLIER RUNS. NO ONE MODEL WITH BETTER
SHORT-TERM RUN-TO-RUN CONSISTENCY THIS CYCLE.
CHECK OF OBS VS. MODEL DATA AT 06Z SHOWED ALL TO BE REASONABLE WITH
THE LK SUPERIOR LOW AND TROUGHS ACROSS THE REGION. MODELS AGAIN
HAVING SOME DIFFICULTY WITH THE SFC DEW POINTS ACROSS THE MID/UPPER
MS VALLEY. PER WV IMAGERY ALL LOOKED QUITE GOOD WITH THE SHORTWAVE
DETAILS OVER NOAM/EASTERN PAC. BLEND OF MODELS REASONABLE WITH THE
LIGHT PRECIP IN THE 00-06Z PERIOD ACROSS THE NORTH-CENTRAL CONUS.
WITH NO ONE MODEL FAVORITE AND THE TREND TOWARD A TIGHTER
CONSENSUS...AGAIN FAVORED A MODEL/ENSEMBLE BLEND. SHORT-TERM FCST
CONFIDENCE REMAINS GOOD THIS CYCLE.
FOR THE SHORT TERM...PER AREA WSR-88D/S...BACK EDGE OF THE -SN
ACROSS MN WAS NEAR A KDLH-JUST NORTHWEST OF KMSP/KSTP LINE AT 08Z...
MAKING STEADY PROGRESS SOUTHEAST. THIS BACK EDGE LINES UP WITH THE
SHORTWAVE/SECONDARY MID LEVEL TROUGH AXIS OVER MN. THIS SHORTWAVE/
TROUGH AXIS DROPS SOUTHEAST THRU THE FCST AREA IN THE 09-15Z TIME-
FRAME THIS MORNING...WITH A RATHER RAPID DECREASE OF MOISTURE DEPTH
ONCE IT PASSES. MODELS CONTINUE TO INDICATE MOISTURE DEPTH TO ABOUT
800MB AHEAD OF THIS FEATURE...WITH 850-800MB TEMPS IN THE -10C TO
-12C RANGE. WILL CONTINUE FLURRY MENTION THIS MORNING...MAINLY IN
THE 12-15Z PERIOD UNTIL THE MID LEVEL TROUGH AXIS PASSES. COLD
ADVECTION/DRYING SPREAD ACROSS THE AREA FOR THE LATE MORNING WITH
CLOUDS EXPECTED TO DECREASE DURING THE AFTERNOON. HIGHS LOOKING TO
BE IN THE 12-15Z PERIOD. TEMPS FALL DURING THE LATE MORNING WITH
NORTHWEST FLOW/COLD ADVECTION BEHIND THE TROUGH THEN NEARLY STEADY
DURING THE AFTERNOON.
MDT/STRONG 925-850MB WARM ADVECTION QUICKLY SPREADS ACROSS THE
REGION TONIGHT AS STRONG HGT RISES MOVE IN BEHIND THE DEPARTING
TROUGH. LOWS TONIGHT LOOKING TO BE DURING THE EVENING THEN
STEADY/SLOWLY RISE AFTER MIDNIGHT. WILL ADD THIS TREND TO THE FCST
GRIDS WITH SOME SOUTHWEST WINDS 5-12KTS LATER TONIGHT. WARM
ADVECTION CONTINUES FRI WITH 925MB TEMPS RISING INTO THE -2C TO +2C
RANGE BY 00Z SAT. WITH A DEEP DRY AIRMASS OVER THE AREA...PLENTY OF
SUNSHINE AND SOME SOUTHWEST WINDS OF 6-14KTS FOR MIXING...HIGHS FRI
LOOKING TO WARM MOSTLY INTO THE 25-30F RANGE. WEAKER GRADIENT WINDS
OVER THE AREA FRI NIGHT AS BROAD/WEAK LOW PRESSURE MOVES INTO MN.
WITH THE DEEP...DRY AIRMASS OVER THE AREA...RADIATIONAL COOLING OVER
THE SNOW COVER SHOULD ALLOW LOWS FRI NIGHT TO FALL TO NEAR NORMAL
VALUES.
925-500MB AIRMASS/COLUMN COOLS WITH APPROACH OF THE NEXT MID LEVEL
TROUGH. LATEST MODEL TREND IS DRIER ON THE LOW LEVEL MOISTURE
INCREASE ACROSS THE AREA WITH THIS TROUGH. DUE TO THE SLOWING
TREND WITH THE TROUGH...WHAT MOISTURE INCREASE THAT DOES OCCUR IS
MOSTLY SAT NIGHT. EVEN THEN...THE MOISTURE IS SHALLOW...AT OR BELOW
ABOUT 900MB. WITH THE SLOWER TROUGH APPROACH AND SMALLER MOISTURE
INCREASE...REMOVED FLURRY MENTION FROM SAT. BASED ON THERMAL
PROFILES AND LACK OF ICE IN THE LOW CLOUD/MOISTURE LAYER...IF ANY
PRECIP WERE TO OCCUR SAT NIGHT IT WOULD BE -FZDZ. LEFT SAT NIGHT DRY
WITH THE LIMITED MOISTURE...THE AREA BEHIND THE SFC-850MB TROUGH
AXIS...AND LITTLE IF ANY LIFT IN/UNDER THE SFC-850MB INVERSION.
GENERALLY FAVORED A BLEND OF THE NUMERICAL TEMP GUIDANCE FOR HIGHS/
LOWS TODAY THRU SAT NIGHT. DID AS SOME NON-DIURNAL TEMPERATURE
TRENDS GRIDS FOR TODAY/TONIGHT.
.LONG TERM...SUNDAY THROUGH WEDNESDAY
341 AM CST THU JAN 3 2013
03.00Z MEDIUM RANGE MODELS IN GENERAL AGREEMENT FOR TRANSITION TO
ZONAL FLOW ACROSS THE NORTHERN CONUS BY TUE/WED AND A RATHER MILD
JANUARY PERIOD OF WEATHER FOR THE AREA MUCH OF NEXT WEEK. LONG TERM
FCST CONFIDENCE AVERAGE.
GOOD MODEL CONSENSUS FOR SHORTWAVE RIDGING TO BUILD ACROSS THE
REGION SUNDAY/SUN NIGHT. ANOTHER ROUND OF LOW LEVEL WARM ADVECTION
SPREADS A WARM/DRY AIRMASS FROM THE CENTRAL/WESTERN PLAINS INTO THE
AREA BUT A SFC RIDGE OF HIGHS PRESSURE IS OVER THE REGION FOR LIGHT
WINDS AND LIMITED BOUNDARY LAYER MIXING. TEMPS TREND NEAR NORMAL
FOR SUNDAY...WITH WARMING SUN NIGHT INTO MON AS GRADIENT TIGHTENS/
SFC WINDS INCREASE WITH THE NEXT TROUGH/LOW PASSING WELL NORTH OF
THE FCST AREA. WITH THE FLOW TRANSITIONING TO ZONAL FOR TUE/WED...
WEST/ SOUTHWEST LOW LEVEL FLOW AND WARM ADVECTION CONTINUE ACROSS
THE UPPER MIDWEST. MDT PRESSURE GRADIENT LOOKS TO REMAIN OVER THE
REGION TUE/WED FOR SOME SOUTHWEST WINDS AND CONTINUED BOUNDARY LAYER
MIXING. MODEL CONSENSUS HIGHS IN THE MON-WED FCST GRIDS TRENDED
ABOVE NORMAL AND MAY STILL BE ON THE COLD SIDE DEPENDING ON CLOUD
COVER AND STRENGTH OF WINDS/LOW LEVEL MIXING. GIVEN THE PROGGED
925MB TEMPERATURES BY TUE/WED...STRONGER MIXING WOULD PUSH HIGHS
THESE DAYS WELL INTO THE 40S. STAYED WITH THE MODEL/ENSEMBLE
CONSENSUS HIGHS/LOWS AT THIS TIME WHICH LEAVES GRIDS WELL
COLLABORATED WITH THE NEIGHBORS.
&&
.AVIATION...THROUGH 18Z FRIDAY
1113 AM CST THU JAN 3 2013
WEAK SURFACE RIDGE CENTERED OVER NEBRASKA WITH THE RIDGE AXIS
NORTH INTO MINNESOTA. MVFR CLOUDS EAST OF THE RIDGE AXIS ARE MOVING
SLOWLY TO THE SOUTHEAST AND ARE EXPECTED TO CLEAR BOTH TAF SITES
LATE THIS AFTERNOON. WILL SEE THE FLURRIES CONTINUE UNTIL THE
CLOUDS CLEAR THE AREA AS THE 03.15Z RAP SOUNDINGS SHOW SOME WEAK
OMEGA THROUGH THE SATURATED LAYER. ONCE THE CLOUDS CLEAR OUT...VFR
CONDITIONS WITH CLEAR SKIES EXPECTED FOR THE REMAINDER OF THE
PERIOD. THE CENTER OF THE SURFACE RIDGE WILL MOVE INTO KANSAS AND
OKLAHOMA TONIGHT AND ONCE THE RIDGE AXIS MOVES THROUGH...THE AREA
WILL BE IN THE PRESSURE GRADIENT FROM A SYSTEM PASSING ACROSS
SOUTHERN CANADA. THIS WILL BE ENOUGH TO KEEP THE WINDS UP AROUND
10 KNOTS OUT OF THE SOUTHWEST.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
341 AM CST THU JAN 3 2013
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...RRS
LONG TERM....RRS
AVIATION...04
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
1129 PM CST WED JAN 2 2013
.SHORT TERM...TONIGHT
925 PM CST WED JAN 2 2013
THE MAIN CONCERNS IN THE NEAR TERM ARE WITH THE PRECIPITATION
TRENDS THROUGH THE EVENING AND OVERNIGHT HOURS. THE MAIN BAND OF
SNOW ASSOCIATED WITH SOME LOW LEVEL WARM AIR ADVECTION AHEAD OF AN
UPPER LEVEL TROUGH CONTINUES TO MOVE EAST ACROSS THE UPPER
MISSISSIPPI RIVER VALLEY REGION WITH SNOWFALL TOTALS REMAINING ON
THE LIGHT SIDE. THIS 1-2 HOUR BAND OF SNOW HAS PRODUCED JUST A
DUSTING OF SNOW WITH A FEW TENTHS OF AN INCH REPORTED IN SOUTHEAST
MINNESOTA. RADAR TRENDS INDICATE THAT THIS BAND OF SNOW HAS BEEN
DISSIPATING AS THE OVERALL LIFT WEAKENS TO THE EAST. CURRENT
TRENDS SHOW THAT THE BACK EDGE OF THE SNOW SHOULD BE INTO CENTRAL
WISCONSIN SOMETIME SHORTLY AFTER MIDNIGHT.
WHAT HAPPENS AS THE SNOW ENDS IS A TOUGHER QUESTION. IN THE REGION
WEST OF THE SNOW AND EAST OF THE COLD FRONT...THERE IS AN AREA
WHERE LOW LEVEL SATURATION IS OCCURRING UNDER A SHARP INVERSION.
THIS HAS LED TO THE FORMATION OF A LOW CLOUD DECK AND SOME PATCHY
FOG THAT HAS MAINLY BEEN IN THE 1-4SM RANGE. THERE IS CONCERN THAT
SOME PATCHY FREEZING DRIZZLE MAY OCCUR AS WELL AS THIS SATURATED
LAYER APPEARS TO BE JUST WARM ENOUGH THAT ICE PRODUCTION MAY NOT
BE OCCURRING. THERE DOES NOT APPEAR TO BE MUCH LOW LEVEL LIFT
THOUGH TO PRODUCE ANY KIND OF PRECIPITATION. MPX RECEIVED A FEW
REPORTS OF FREEZING DRIZZLE EARLIER IN THE EVENING...BUT THE
THREAT OF IT APPEARS TO BE DIMINISHING GOING THROUGH THE REST OF
THE NIGHT. MADE SOME CALLS TO COUNTY SHERIFF DEPARTMENTS IN
SOUTHEAST MINNESOTA WHERE VISIBILITY HAS BEEN THE LOWEST AND THEY
HAVE NOT HAD ANY ISSUES WITH ICING OUT THERE. SO...WILL CONTINUE
TO KEEP AN EYE ON THIS BUT WILL KEEP THE MENTION OUT OF THE
FORECAST FOR TONIGHT AND JUST LEAVE SOME FLURRIES IN THERE WITH
THE LOWER CLOUDS.
WINDS WILL SHIFT AROUND TO THE NORTHWEST QUICKLY TONIGHT AND
APPEAR TO BE DOING SO FASTER THAN WHAT THE 02.22Z-03.01Z RAP HAD
BEEN ADVERTISING. CEILINGS WILL PICK UP ONCE THE WIND SHIFT COMES
THROUGH...SO ANY DRIZZLE THREAT WILL END AS THIS FEATURE COMES IN.
SKIES WILL REMAIN GENERALLY CLOUDY INTO TOMORROW WITH COLD AIR
ADVECTION KICKING IN FROM THE NORTHWEST BEHIND THE FRONT.
.LONG TERM...
252 PM CST WED JAN 2 2013
THE OVERALL WARMING TREND LOOKS TO CONTINUE INTO THE LONG TERM
FORECAST PERIOD. THE FLOW REGIME LOOKS TO BECOME A BIT MORE ZONAL
ALONG THE INTERNATIONAL BORDER BY THE START OF NEXT WEEK...WITH A
SHIFT TO SOUTHWEST FLOW IN THE OFFING FOR THE END OF THE WEEK. IN
ADDITION...A CLOSED CIRCULATION OFF THE WEST COAST WILL MOVE
ONSHORE SOMEWHERE NEAR CA OR THE BAJA BY TUESDAY MORNING. THIS
SYSTEM WILL EVENTUALLY MOVE INTO OUR AREA...BUT MODELS DIFFER ON
THE EVOLUTION AND TIMING OF THAT SYSTEM. EITHER WAY...IT IS
LOOKING LIKE MUCH WARMER TEMPERATURES WILL OCCUR AHEAD OF THAT
SYSTEM. IN FACT...THERE ARE SOME INDICATIONS THAT THE PRECIPITATION
AHEAD OF IT WILL FALL AS RAIN. SO THIS SYSTEM DEFINITELY BEARS
WATCHING.
&&
.AVIATION...THROUGH 06Z FRIDAY
1129 PM CST WED JAN 2 2013
THE MAIN SNOW HAS ENDED AT THE TAF SITES...BUT SCATTERED FLURRIES
WILL PERSIST INTO THE MORNING AND EARLY AFTERNOON HOURS ON
THURSDAY. IFR CEILINGS AT RST ARE EXPECTED TO IMPROVE TO MVFR
QUICKLY OVERNIGHT AS WINDS SHIFT TO THE NORTHWEST WITH DRIER NEAR
SURFACE AIR MOVING IN. THESE 1-2.5KFT CEILINGS EXTEND WELL ACROSS
MINNESOTA AND SHOULD LINGER INTO THURSDAY AFTERNOON AS WELL
THOUGH A FEW BREAKS TO VFR WILL LIKELY OCCUR. WINDS WILL BECOME
GUSTY OUT OF THE NORTHWEST OVERNIGHT AS A COLD FRONT MOVES THROUGH
THE REGION WITH TOP GUSTS IN THE 18 TO 24KT RANGE. CONDITIONS ARE
EXPECTED TO GRADUALLY IMPROVE THROUGH THE AFTERNOON THURSDAY AS
THE SYSTEM THAT BROUGHT THE SNOW AND CLOUD COVER MOVES OFF TO THE
EAST INTO THE GREAT LAKES.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
252 PM CST WED JAN 2 2013
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...HALBACH
LONG TERM...MW
AVIATION...HALBACH
AREA FORECAST DISCUSSION
NWS GOODLAND KS
237 AM MST SAT JAN 5 2013
.SHORT TERM...(TODAY THROUGH SUNDAY)
ISSUED AT 236 AM MST SAT JAN 5 2013
04Z WATER VAPOR IMAGERY AND RAP ANALYSIS INDICATED UPPER LEVEL LOW
CIRCULATION CENTERED OVER THE OKLAHOMA PANHANDLE MOVING
NORTHEAST...WITH A SECOND SHORT WAVE TROUGH DIVING TO THE SOUTHEAST
ACROSS THE NORTHERN PLAINS. FOR THE MOST PART...00Z SOUNDINGS HAD
WARMED AND DRIED FROM 24 HOURS AGO WITH THE ONLY EXCEPTION BEING
H75-H5 MOISTENING AT DDC IN ADVANCE OF SOUTHERN LOW. MOISTENING WAS
LIMITED TO THIS LEVEL HOWEVER...WITH LARGE SUB CLOUD DRY LATER
NOTED.
TODAY-SUNDAY...TROUGH TO THE SOUTH WILL GRADUALLY LIFT TO THE
NORTHEAST THIS MORNING AS NEXT SYSTEM APPROACHES FROM THE NORTH.
WHILE THERE IS A BIT OF ASCENT EXPECTED...SYSTEMS FOR THE MOST PART
DO NOT BRING ANY MEANINGFUL INFLUX OF MOISTURE TO THE AREA. WITH
OBSERVED SOUNDINGS AROUND THE AREA INDICATING VERY DRY
CONDITIONS...ESPECIALLY BELOW H7...LEADS ME TO THINK DEPARTING
SYSTEM WILL LEAD TO MUCH MORE THAN A PERIOD OF MID CLOUDS...ALTHOUGH
WILL MONITOR. SYSTEM APPROACHING FROM THE NORTH WILL HAVE SIMILAR
MOISTURE AVAILABILITY ISSUES DURING THE AFTERNOON AS IT MOVES ACROSS
THE AREA. MAIN CONCERN WITH THIS SECOND SYSTEM WILL BE THE SHARP
INCREASE IN WIND SPEEDS OFF OF THE SURFACE...ESPECIALLY AS
SUBSIDENCE INCREASES IN THE AFTERNOON. HAVE BUMPED UP THE WINDS INTO
THE 15 TO 25 MPH CATEGORY FOR THE TIME BEING...AS THE LINGERING
IMPACT OF SNOW COVER MAKES CONFIDENCE IN DEEP MIXING TOO LOW TO
BRING DOWN HIGHER SPEEDS. STRONG SUBSIDENCE WILL OVERSPREAD THE AREA
TONIGHT AS SHORT WAVE RIDGE MOVES OVER THE AREA. THIS WILL LEAD TO
CONTINUED DRY AND MOSTLY CLEAR CONDITIONS THROUGH SUNDAY MORNING
BEFORE CLOUDS BEGIN TO INCREASE LATE IN THE AFTERNOON AS RIDGE
SHIFTS TO THE EAST OF THE AREA. OVERALL CURRENT FORECAST LOOKS
REASONABLE CONSIDERING LATEST SUITE OF DATA AND ONLY MADE A FEW
MINOR CHANGES TO TEMPS.
.LONG TERM...(SUNDAY NIGHT THROUGH FRIDAY)
ISSUED AT 236 AM MST SAT JAN 5 2013
SUNDAY NIGHT-MONDAY NIGHT...H5 TROUGH WILL SPLIT INTO A NORTHERN AND
SOUTHERN SYSTEM OVER THE WESTERN CONUS WITH GOOD MODEL AGREEMENT
THAT SOUTHERN TROUGH WILL DIVE TO THE SOUTH ALONG THE US/MEXICO
BORDER AND REMAINING WELL TO THE SOUTH OF THE AREA WHILE NORTHERN
TROUGH MOVES ACROSS THE NORTHERN PLAINS. WITH THE EXPECTED TRACK OF
THE UPPER LEVEL SYSTEMS...EXPECT DRY CONDITIONS TO CONTINUE ACROSS
THE AREA WITH NO MEANINGFUL THREAT FOR PRECIPITATION. THESE SYSTEMS
WILL STILL HAVE A SMALL IMPACT ON THE AREA AS SFC TROUGH DEEPENS ON
SUNDAY RESULTING IN SOUTHERLY WINDS INCREASING TO 15 TO 25MPH LATE
SUNDAY AFTERNOON AND REMAIN GUSTY OVERNIGHT. EXPECTING THIS TO HOLD
UP MIN TEMPERATURES SEVERAL DEGREES WITH A FEW AREAS REMAINING ABOVE
NORMAL FOR LOWS.
TUESDAY THROUGH FRIDAY...MODELS HAVE COME INTO BETTER AGREEMENT
WITH THE DEVELOPMENT/TRACK OF THE UPPER LEVEL LOW OVER THE DESERT
SOUTHWEST ON TUESDAY. MODELS HAVE THE CLOSED LOW MOVING OVER
OKLAHOMA AND NORTHERN TEXAS WEDNESDAY NIGHT. AS THE LOW MOVES
NORTH ISENTROPIC LIFT WILL DEVELOP OVER THE SOUTHEAST PART OF THE
AREA...LEADING TO SOME CHANCES FOR PRECIPITATION. AS THE CLOSED
LOW MOVES NORTHEAST THURSDAY PRECIPIATION WILL COME TO AN END.
THURSDAY ANOTHER UPPER LEVEL TROUGH WILL MOVE OVER THE
INTER-MOUNTAIN WEST TOWARD THE AREA. AHEAD OF THE UPPER LEVEL
TROUGH A COLD FRONT WILL MOVE INTO THE AREA LATE THURSDAY NIGHT.
PRECIPITATION CHANCES INCREASE BEHIND THE FRONT AS
ISENTROPIC/SYNOPIC LIFT AND MOISTURE INCREASE. AT THIS TIME WILL
KEEP PRECIPIATION CHANCES AND MOISTURE AMOUNTS ON THE LOW END DUE TO
FAIRLY WEAK LIFT AHEAD OF THE TROUGH.
TEMPERATURES FOR THE PERIOD WILL BE NEAR NORMAL THROUGH THURSDAY.
BELOW NORMAL TEMPERATURES RETURN BEHIND THE COLD FRONT THURSDAY
NIGHT.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SATURDAY NIGHT)
ISSUED AT 1010 PM MST FRI JAN 4 2013
VFR THROUGH THE PERIOD AT KGLD AND KMCK. SFC TROUGH MOVES THROUGH
SHORTLY AFTER AROUND 06Z BRINGING NORTHWEST WINDS AROUND 10KTS.
THESE WINDS WILL BECOME GUSTY DURING THE DAY SATURDAY WITH
25-30KTS POSSIBLE. CLOUDINESS THROUGH MORNING GENERALLY AT CIRRUS
LEVEL WITH SOME CLOUDS AROUND 7K AND 12K FEET AT KMCK DURING THE
AFTERNOON.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
CO...NONE.
NE...NONE.
&&
$$
SHORT TERM...JRM
LONG TERM...JRM/JTL
AVIATION...99
AREA FORECAST DISCUSSION
NWS DODGE CITY KS
1202 AM CST SAT JAN 5 2013
...UPDATE TO SYNOPSIS...
.SYNOPSIS...
ISSUED AT 1200 AM CST SAT JAN 5 2013
WV IMAGERY AND 00Z UPPER AIR ANALYSIS INDICATE A CLOSED OFF UPPER
LEVEL LOW LIFTING NORTHEAST ACROSS THE TEXAS PANHANDLE. MEANWHILE,
A FAIRLY WEAK FLOW ALOFT PERSISTS ACROSS WESTERN KANSAS. NEAR THE
SURFACE, A LEE SIDE TROUGH OF LOW PRESSURE IN EASTERN COLORADO IS
PUSHING SLOWLY EASTWARD TOWARD THE KANSAS BORDER. SURFACE DEWPOINTS
ARE MAINLY IN THE 20S(F) ACROSS SOUTHWEST AND SOUTH CENTRAL KANSAS
WITH A FEW TEENS(F) ACROSS WEST CENTRAL KANSAS.
&&
.SHORT TERM...(THIS EVENING THROUGH TOMORROW)
ISSUED AT 254 PM CST FRI JAN 4 2013
THE UPPER LOW IS PROGGED BY THE MODELS TO MOVE FROM NEW MEXICO THIS
AFTERNOON THROUGH THE TEXAS PANHANDLE INTO EASTERN KANSAS BY
SATURDAY AFTERNOON. MODEL SOUNDINGS MOISTEN UP IN THE MID LEVELS
ACROSS SOUTH CENTRAL KANSAS THIS EVENING AND START TO MOISTEN
DOWNWARD WITH TIME. THE MODELS CONTINUE TO BE SKIMPY ON QPF WITH
THIS SYSTEM WHICH MAKES SENSE GIVEN THE LIMITED MOISTURE. THINK
THAT THERE COULD AT LEAST BE SOME FLURRIES FOR A PERIOD OF TIME
TONIGHT AND HAVE ADDED THAT TO THE GRIDS IN SOUTH CENTRAL KANSAS.
SURFACE WINDS WERE GRADUALLY VEERING WITH TIME THIS AFTERNOON AS THE
EASTERN COLORADO TROUGH DEEPENS IN ADVANCE OF THE UPPER WAVE. THIS
WILL ALLOW WEAK LOW LEVEL MOIST ADVECTION TO OCCUR OVER SOUTHWEST
KANSAS THIS EVENING. WITH THE MOISTURE RIDING UP OVER SNOW COVERED
GROUND, WE SHOULD SEE SOME FOG DEVELOP LATER THIS EVENING AND
CONTINUING THROUGH TONIGHT. MOS OUTPUT IS NOT INDICATING ANY
REDUCTION IN VISIBILITY AT ALL TONIGHT AND THE HRRR MODEL DOES NOT
INDICATE MUCH EITHER BEFORE 08Z. THE SREF PROBABILITIES DO SHOW SOME
INCREASED CHANCES FOR FOG SO WILL CONTINUE THE TREND OF SOME AREAS
OF FOG DEVELOPING. WILL ALSO START THE AREAS OF FOG FARTHER WEST
TOWARD GARDEN CITY AND SYRACUSE LATE THIS EVENING. FOR NOW WILL
HOLD OFF ON ANY HEADLINES AND LET THE NEXT SHIFT MAKE THAT
ASSESSMENT.
ON SATURDAY THE ANY LINGERING FOG IN THE EARLY MORNING SHOULD
DISSIPATE OR MOVE EAST OUT OF CENTRAL KANSAS AS THE SURFACE TROUGH
CONTINUES EAST. THE REMAINDER OF THE DAY SHOULD SEE MAINLY SUNNY
SKIES. WITH A LITTLE BETTER MIXING THAN TODAY, HIGH TEMPERATURES
SHOULD BE ABLE TO CLIMB INTO THE 30S OVER THE SNOW COVERED AREAS
WITH LOWER TO MIDDLE 40S IN SOUTH CENTRAL KANSAS WHERE THE SNOW HAS
MELTED.
.LONG TERM...(SATURDAY NIGHT THROUGH FRIDAY)
ISSUED AT 227 PM CST FRI JAN 4 2013
A WEAK, UPPER LEVEL HIGH PRESSURE RIDGE OVER THE PLAINS SUNDAY AND
INTO MONDAY WILL START TO BREAK DOWN BY LATE TUESDAY, AS A LARGE
UPPER LEVEL LOW PRESSURE SYSTEM APPROACHES FROM THE SOUTHWEST.
BOTH SUNDAY AND MONDAY WILL BE WARMER THAN IT HAS BEEN RECENTLY,
AND PLENTY OF SUNSHINE SHOULD HELP MELT MORE OF THE SNOW COVER.
HIGHS SUNDAY, MONDAY AND TUESDAY WILL RANGE FROM AROUND THE 40F
DEGREE NORTH OF THE I-70, TO THE MID TO UPPER 40S ALONG AND NEAR
THE OKLAHOMA BORDER. THEN ON TUESDAY NIGHT, SYNOPTIC SCALE LIFT
WILL RESULT FROM THE CLOSED LOW APPROACHING FROM THE SOUTHWEST.
MOISTURE WILL BE DEEPENING AND ADVECTING NORTH INTO SOUTHWESTERN
KANSAS, AND ESPECIALLY SOUTH CENTRAL KANSAS. THAT UPPER SYSTEM
WILL CONTINUE TO MARCH INTO THE TEXAS PANHANDLE BY 09/18Z OR WED
AFTERNOON, WHERE IT WILL THEN BEGIN TO LIFT NORTHEAST AND START TO
OPEN UP AS A WAVE, AT THE SAME TIME. AS FOR PRECIPITATION, THE
GOING 20 TO 30 PERCENT OF PRECIPITATION CHANCES, BASICALLY
SOUTHEAST OF A LIBERAL TO PRATT LINE, THROUGH WED/12Z SEEM
REASONABLE. THEN AS THE UPPER LOW LIFTS NORTHEAST LATE WEDNESDAY
INTO EASTERN KANSAS, 20(WEST) TO 35 (EAST) PRECIPITATION CHANCES
WEDNESDAY AFTERNOON AND NIGHT ACROSS ALL OF SOUTHWESTERN KANSAS
ALSO SEEM APPROPRIATE. PRECIPITATION TYPE WILL VARY FROM RAIN OR
SNOW IN THE DAY TIMES AND LIGHT SNOW IN THE NIGHT TIMES. AS THE
UPPER SYSTEM LIFTS OUT WEDNESDAY NIGHT, IT SHOULD ACCELERATE, AND
CHANCES FOR PRECIPITATION WILL QUICKLY END LATE WEDNESDAY NIGHT OR
VERY EARLY THURSDAY MORNING. AS THIS OCCURS, THERE WILL BE
CLEARING AND COOLING THURSDAY. A LITTLE WRAP-AROUND COLD AIR WILL
FILTER BACK INTO THE SOUTHWESTERN KANSAS FRIDAY, AND A LITTLE
LIGHT SNOW MAY DEVELOP. LOWER 20 PERCENT CHANCES FOR LIGHT SNOW
EXIST FOR FRIDAY.
WEDNESDAY AND THURSDAY LOOK TO WARM INTO THE LOWER TO MIDDLE 40S
NORTH OF JETMORE, AND AROUND 50F DEGREES SOUTH OF THE JETMORE-DODGE
CITY AREAS. ON FRIDAY, IT WILL COOL OFF TO HIGHS IN THE 30S.
MINIMUM TEMPERATURES WILL START OUT COLD SATURDAY MORNING, IN THE
TEENS OVER THE SNOW PACKED AREAS NORTHWEST OF A WAKEENEY TO GARDEN
CITY TO ELKHART LINE, AND RANGE TO THE MID 20S IN THE COLDWATER AND
MEDICINE LODGE AREAS. MEDIUM RANGE MODELS WARM MINIMUMS TO AROUND
THE 20F DEGREE MARK IN THE SCOTT CITY AREA BY TUESDAY, AND TO NEAR
30F DEGREES IN THE PRATT AREA. THE SLIGHT WARMING TREND WILL EXTEND
INTO THURSDAY MORNING, WITH LOWS FROM THE MID 20S IN SYRACUSE AND
SCOTT CITY, RANGING TO THE LOWER 30S IN PRATT, KIOWA AND COLDWATER.
MINIMUMS FRIDAY WILL TURN COOLER FROM AROUND 20F DEGREES IN THE KEARNY
COUNTY AREA TO THE UPPER 20S IN THE BARBER COUNTY AREA. SATURDAY
MORNING (DAY 8) SHOULD BE EVEN COLDER.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SATURDAY NIGHT)
ISSUED AT 1100 PM CST FRI JAN 4 2013
VFR CONDITIONS ARE EXPECTED TO CONTINUE AT ALL TAF SITES
OVERNIGHT. HOWEVER, LIGHT SOUTHERLY WINDS AND HIGH RELATIVE
HUMIDITIES MAY ALLOW FOR THE DEVELOPMENT OF LOW LEVEL STRATUS
AROUND DAYBREAK FROM THE TEXAS PANHANDLE NORTHWARD INTO PORTIONS
OF SOUTHWEST KANSAS...POTENTIALLY AFFECTING KDDC AND KGCK.
MVFR/IFR CIGS AND VSBYS MAY BE POSSIBLE BRIEFLY AT KDDC...AND
ALTHOUGH LESS LIKELY...KGCK GENERALLY AFTER 10Z TO 12Z. OTHERWISE,
VFR CONDITIONS WILL DOMINATE THROUGH THE DAY SATURDAY. AS FOR
WINDS, A SURFACE TROUGH OF LOW PRESSURE IN EASTERN COLORADO WILL
EDGE SLOWLY EASTWARD ACROSS WESTERN KANSAS EARLY SATURDAY MORNING.
THIS WILL RESULT IN LIGHT SOUTHWESTERLY WINDS BECOMING
NORTHWESTERLY 10 TO 20KT BY SATURDAY EARLY AFTERNOON.
&&
.PRELIMINARY POINT TEMPS/POPS...
DDC 38 16 43 20 / 0 0 0 0
GCK 36 13 42 18 / 0 0 0 0
EHA 41 16 45 22 / 0 0 0 0
LBL 39 14 45 19 / 0 0 0 0
HYS 35 16 37 18 / 0 0 0 0
P28 42 20 44 21 / 0 0 0 0
&&
.DDC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...JJOHNSON
SHORT TERM...GERARD
LONG TERM...BURKE
AVIATION...JJOHNSON
AREA FORECAST DISCUSSION
NWS WICHITA KS
1136 PM CST FRI JAN 4 2013
.AVIATION...06Z TAFS KRSL/KSLN/KHUT/KICT/KCNU
UPPER LOW WILL PROGRESS NORTHEAST OVER THE REGION
TONIGHT...SPREADING DENSE LOW TO MID LEVEL CLOUDS ACROSS THE AREA.
COULD SEE A FEW AREAS OF LIGHT SNOW/FLURRIES ESPECIALLY OVER KCNU
LATE TONIGHT THROUGH EARLY SATURDAY...WITH A FEW FLURRIES NOT
COMPLETELY OUT OF THE PICTURE FOR ALL OTHER SITES...BUT SCENARIO
NOT LOOKING AS FAVORABLE AS PREVIOUS FORECASTS. OTHERWISE...LOW
VFR CIGS AROUND 3000-4000 FT AGL WILL LIKELY MOVE INTO KICT-KCNU
AND MAYBE KHUT BY 08-10 UTC...PERSISTING INTO SATURDAY
MORNING...LONGEST FOR KCNU. A WEAK WIND SHIFT WILL PASS ACROSS THE
REGION SATURDAY...SWITCHING WINDS FROM SOUTHWESTERLY TO
WEST/NORTHWESTERLY BY AFTERNOON.
ADK
&&
.PREV DISCUSSION... /ISSUED 1002 PM CST FRI JAN 4 2013/
UPDATE...
SNOW CHANCES NOT LOOKING AS GOOD OVERNIGHT DUE TO DRY SUB-CLOUD
LAYER AND LIMITED MOISTURE. LATEST EVENING SOUNDINGS ARE QUITE
DRY...AND PRECIPITATION NEAR/UNDER THE UPPER LOW OVER WESTERN KS
AND THE PANHANDLES OF OK/TX HAS HAD A TOUGH TIME REACHING THE
GROUND. ADDITIONALLY...LATEST RUC AND 00Z NAM HAVE BACKED OFF ON
PRECIPITATION AMOUNTS...WITH THE GREATEST 700-600MB MOISTURE
TRAJECTORIES TARGETING THE OZARKS OF AR/MO. HOWEVER...HELD ONTO
40-50 POPS OVER FAR SOUTHEAST KS FROM ABOUT 3AM--8AM...AS LATEST
HRRR CONTINUES TO SHOW SOME QPF LATER TONIGHT THROUGH EARLY
SATURDAY. ANTICIPATING NO MORE THAN A DUSTING SNOW ACCUMULATION.
THINKING PATCHY FLURRIES WILL BE POSSIBLE AS FAR WEST/NORTHWEST AS
CENTRAL KS UNDERNEATH UPPER LOW.
ADDITIONALLY...REMOVED PATCHY FOG WORDING FROM THE FORECAST...AS
SURFACE-BOUNDARY LAYER FLOW WILL LIKELY BE TOO HIGH FOR ANY FOG
FORMATION.
ADK
PREV DISCUSSION... /ISSUED 549 PM CST FRI JAN 4 2013/
AVIATION...00Z TAFS KRSL/KSLN/KHUT/KICT/KCNU
AN UPPER LEVEL LOW WILL DRIFT NORTHEAST ACROSS THE REGION
TONIGHT...SPREADING DENSE LOW TO MID-LEVEL CLOUDS NORTHEAST.
THINKING ALL SITES WILL REMAIN VFR EXCEPT KCNU...WHERE A QUICK
SHOT OF LIGHT SNOW AND LOW MVFR OR HIGH IFR CIGS WILL BE POSSIBLE
FROM ABOUT 10-14 UTC. ANTICIPATING ACCUMULATIONS TO REMAIN UNDER
ONE-HALF INCH. FURTHER WEST ACROSS THE REST OF CENTRAL AND EASTERN
KS...PERIODIC FLURRIES CANNOT BE RULED OUT FROM ABOUT 08-14
UTC...BUT THINKING MOST AREAS WILL REMAIN PRECIPITATION-FREE DUE
TO A DRY SUB-CLOUD LAYER. OTHERWISE...CLOUDS/PRECIPITATION SHOULD
EXIT EASTERN KS BY LATE MORNING/EARLY AFTERNOON SATURDAY...WITH A
WEAK SURFACE TROUGH SHIFTING WINDS FROM SOUTHWESTERLY TO
WEST/NORTHWESTERLY IN THE AFTERNOON.
ADK
PREV DISCUSSION... /ISSUED 158 PM CST FRI JAN 4 2013/
DISCUSSION...
FORECAST CHALLENGES...LIGHT SNOW CHANCES EARLY SATURDAY MORNING
AND THEN PRECIP CHANCES AGAIN NEXT WEEK.
TONIGHT-MONDAY
UPPER LOW OVER NEW MEXICO WILL LIFT NORTHEAST ACROSS THE TEXAS
PANHANDLE EARLY TONIGHT AND ACROSS SOUTHEAST KANSAS SATURDAY
MORNING. CURRENT FORECAST LOOKS REASONABLE WITH MODEST CHANCE FOR
LIGHT QPF/SNOWS ACROSS SOUTHEAST KANSAS. SOME FLURRIES OR EVEN A
DUSTING OF LIGHT SNOW IS POSSIBLE A BIT FURTHER WEST TO I-135
CORRIDOR...THOUGH BETTER LIFT COINCIDENT WITH RELATIVELY DEEPER
TROPOSPHERIC MOISTENING SHOULD FAVOR SOMEWHAT BETTER CHANCES FOR
LIGHT SNOW ACCUMS ACROSS SOUTHEAST KANSAS. A NORTHERN STREAM UPPER
TROF WILL DIVE SOUTHEAST ACROSS THE MIDWEST SATURDAY NIGHT...WITH
DRY AND SEASONABLY MILD WEATHER EXPECTED FOR THE LATTER PORTION
OF THE WEEKEND. THE EXCEPTIONS BEING OVER THE RESIDUAL SNOW COVER
WHICH WILL KEEP TEMPERATURES A BIT COOLER MAINLY ACROSS CENTRAL
KANSAS.
TUESDAY-FRIDAY
THE MAIN CHALLENGE IN THE OUTER PERIODS CONTINUES TO REVOLVE
AROUND THE HANDLING OF THE SOUTHERN STREAM UPPER TROF MOVING
ACROSS THE SOUTHERN PLAINS NEXT WEEK. THE GFS REMAINS SOMEWHAT
MORE PROGRESSIVE WITH A BIT MORE PHASING OF ENERGY WITHIN THE
NORTHERN STREAM...WHILE THE ECMWF IS MUCH SLOWER. THIS LEADS TO
SOMEWHAT LOWER CONFIDENCE IN THE TRACK AND TIMING OF THE
ASSOCIATED SYNOPTIC FEATURES...SO WILL MAKE LITTLE CHANGE TO THE
GOING FORECAST FOR NOW. THERE DOES SEEM TO BE BETTER CONTINUITY
AND CONFIDENCE IN DEVELOPING A MEAN LONGWAVE UPPER TROF ACROSS
THE WEST BY THE END OF THE WEEK...ALLOWING MUCH COLDER AIR TO BE
POISED AND READY TO DROP SOUTH INTO KANSAS.
DARMOFAL
AVIATION...18Z TAFS KRSL/KSLN/KHUT/KICT/KCNU
THE AVIATION CONCERN IS THE LOW MVFR/IFR CEILINGS AND SNOW CHANCES
FOR KCNU.
AS AN UPPER LEVEL DISTURBANCE APPROACHES THIS AFTERNOON AND
EVENING...MID LEVEL CLOUDS WILL STREAM IN FROM THE SOUTH. AFTER
SUNSET LOWER MVFR CLOUDS WILL MOVE IN IMPACTING PRIMARILY KICT AND
KCNU. SNOW SHOWERS ARE EXPECTED AT KCNU TOWARDS THE MORNING
HOURS...AND HAVE REDUCED VISIBILITIES AND CEILINGS TO IFR RANGE.
VFR CONDITIONS ARE EXPECTED THROUGH THE AFTERNOON AND EARLY
OVERNIGHT HOURS AT ALL TERMINALS UNTIL THOSE LOWER MVFR CEILINGS
MOVE IN. WINDS WILL STAY RELATIVELY LIGHT AND OUT OF THE
SOUTH/SOUTHWEST. TOWARD THE END OF THIS 24 HOUR VALID PERIOD...A
FRONT WILL BEGIN TO MOVE THROUGH THE AREA...CHANGING THE WINDS
AROUND TO THE NORTHWEST...THIS SHOULD IMPACT KRSL BY 15-16Z TOMORROW
AND BEGIN TO IMPACT KSLN BY 18Z.
BILLINGS
&&
.PRELIMINARY POINT TEMPS/POPS...
WICHITA-KICT 26 43 20 44 / 10 10 0 0
HUTCHINSON 24 41 17 42 / 10 10 0 0
NEWTON 25 40 18 40 / 10 10 0 0
ELDORADO 26 41 21 42 / 20 20 0 0
WINFIELD-KWLD 28 45 21 45 / 20 20 0 0
RUSSELL 16 35 13 38 / 10 10 0 0
GREAT BEND 19 36 13 38 / 10 10 0 0
SALINA 21 38 15 39 / 10 10 0 0
MCPHERSON 23 39 16 40 / 10 10 0 0
COFFEYVILLE 29 46 22 40 / 40 40 0 0
CHANUTE 27 44 20 39 / 40 40 0 0
IOLA 27 43 20 39 / 40 40 0 0
PARSONS-KPPF 28 45 21 40 / 40 40 0 0
&&
.ICT WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS DODGE CITY KS
1112 PM CST FRI JAN 4 2013
...UPDATE TO AVIATION...
.SYNOPSIS...
ISSUED AT 254 PM CST FRI JAN 4 2013
THE 12Z UPPER AIR ANALYSIS SHOWED A CLOSED LOW AT 500 MB SPINNING
OVER NEW MEXICO THIS MORNING. THE ANALYSIS SHOWS THAT THIS SYSTEM
DOES NOT HAVE A LOT OF MOISTURE TO WORK WITH BUT SATELLITE IMAGERY
SHOWED MID AND HIGH LEVEL CLOUDINESS AHEAD OF THIS SYSTEM SPREADING
UP TOWARD SOUTHWEST KANSAS THIS AFTERNOON. IN THE LOWER LEVELS, A
RIDGE OF HIGH PRESSURE AT 850 MB EXTENDED FROM SOUTHEAST TEXAS BACK
INTO THE FOUR CORNERS REGION. AT THE SURFACE, A LOW PRESSURE TROUGH
WAS SLOWLY DEEPENING OVER EASTERN COLORADO. SURFACE DEWPOINTS WERE
GENERALLY IN THE TEENS OVER SOUTHWEST KANSAS WHILE FARTHER SOUTH,
OVER THE TEXAS PANHANDLE INTO WESTERN OKLAHOMA, DEWPOINTS WERE IN
THE LOWER TO MIDDLE 20S.
&&
.SHORT TERM...(THIS EVENING THROUGH TOMORROW)
ISSUED AT 254 PM CST FRI JAN 4 2013
THE UPPER LOW IS PROGGED BY THE MODELS TO MOVE FROM NEW MEXICO THIS
AFTERNOON THROUGH THE TEXAS PANHANDLE INTO EASTERN KANSAS BY
SATURDAY AFTERNOON. MODEL SOUNDINGS MOISTEN UP IN THE MID LEVELS
ACROSS SOUTH CENTRAL KANSAS THIS EVENING AND START TO MOISTEN
DOWNWARD WITH TIME. THE MODELS CONTINUE TO BE SKIMPY ON QPF WITH
THIS SYSTEM WHICH MAKES SENSE GIVEN THE LIMITED MOISTURE. THINK
THAT THERE COULD AT LEAST BE SOME FLURRIES FOR A PERIOD OF TIME
TONIGHT AND HAVE ADDED THAT TO THE GRIDS IN SOUTH CENTRAL KANSAS.
SURFACE WINDS WERE GRADUALLY VEERING WITH TIME THIS AFTERNOON AS THE
EASTERN COLORADO TROUGH DEEPENS IN ADVANCE OF THE UPPER WAVE. THIS
WILL ALLOW WEAK LOW LEVEL MOIST ADVECTION TO OCCUR OVER SOUTHWEST
KANSAS THIS EVENING. WITH THE MOISTURE RIDING UP OVER SNOW COVERED
GROUND, WE SHOULD SEE SOME FOG DEVELOP LATER THIS EVENING AND
CONTINUING THROUGH TONIGHT. MOS OUTPUT IS NOT INDICATING ANY
REDUCTION IN VISIBILITY AT ALL TONIGHT AND THE HRRR MODEL DOES NOT
INDICATE MUCH EITHER BEFORE 08Z. THE SREF PROBABILITIES DO SHOW SOME
INCREASED CHANCES FOR FOG SO WILL CONTINUE THE TREND OF SOME AREAS
OF FOG DEVELOPING. WILL ALSO START THE AREAS OF FOG FARTHER WEST
TOWARD GARDEN CITY AND SYRACUSE LATE THIS EVENING. FOR NOW WILL
HOLD OFF ON ANY HEADLINES AND LET THE NEXT SHIFT MAKE THAT
ASSESSMENT.
ON SATURDAY THE ANY LINGERING FOG IN THE EARLY MORNING SHOULD
DISSIPATE OR MOVE EAST OUT OF CENTRAL KANSAS AS THE SURFACE TROUGH
CONTINUES EAST. THE REMAINDER OF THE DAY SHOULD SEE MAINLY SUNNY
SKIES. WITH A LITTLE BETTER MIXING THAN TODAY, HIGH TEMPERATURES
SHOULD BE ABLE TO CLIMB INTO THE 30S OVER THE SNOW COVERED AREAS
WITH LOWER TO MIDDLE 40S IN SOUTH CENTRAL KANSAS WHERE THE SNOW HAS
MELTED.
.LONG TERM...(SATURDAY NIGHT THROUGH FRIDAY)
ISSUED AT 227 PM CST FRI JAN 4 2013
A WEAK, UPPER LEVEL HIGH PRESSURE RIDGE OVER THE PLAINS SUNDAY AND
INTO MONDAY WILL START TO BREAK DOWN BY LATE TUESDAY, AS A LARGE
UPPER LEVEL LOW PRESSURE SYSTEM APPROACHES FROM THE SOUTHWEST.
BOTH SUNDAY AND MONDAY WILL BE WARMER THAN IT HAS BEEN RECENTLY,
AND PLENTY OF SUNSHINE SHOULD HELP MELT MORE OF THE SNOW COVER.
HIGHS SUNDAY, MONDAY AND TUESDAY WILL RANGE FROM AROUND THE 40F
DEGREE NORTH OF THE I-70, TO THE MID TO UPPER 40S ALONG AND NEAR
THE OKLAHOMA BORDER. THEN ON TUESDAY NIGHT, SYNOPTIC SCALE LIFT
WILL RESULT FROM THE CLOSED LOW APPROACHING FROM THE SOUTHWEST.
MOISTURE WILL BE DEEPENING AND ADVECTING NORTH INTO SOUTHWESTERN
KANSAS, AND ESPECIALLY SOUTH CENTRAL KANSAS. THAT UPPER SYSTEM
WILL CONTINUE TO MARCH INTO THE TEXAS PANHANDLE BY 09/18Z OR WED
AFTERNOON, WHERE IT WILL THEN BEGIN TO LIFT NORTHEAST AND START TO
OPEN UP AS A WAVE, AT THE SAME TIME. AS FOR PRECIPITATION, THE
GOING 20 TO 30 PERCENT OF PRECIPITATION CHANCES, BASICALLY
SOUTHEAST OF A LIBERAL TO PRATT LINE, THROUGH WED/12Z SEEM
REASONABLE. THEN AS THE UPPER LOW LIFTS NORTHEAST LATE WEDNESDAY
INTO EASTERN KANSAS, 20(WEST) TO 35 (EAST) PRECIPITATION CHANCES
WEDNESDAY AFTERNOON AND NIGHT ACROSS ALL OF SOUTHWESTERN KANSAS
ALSO SEEM APPROPRIATE. PRECIPITATION TYPE WILL VARY FROM RAIN OR
SNOW IN THE DAY TIMES AND LIGHT SNOW IN THE NIGHT TIMES. AS THE
UPPER SYSTEM LIFTS OUT WEDNESDAY NIGHT, IT SHOULD ACCELERATE, AND
CHANCES FOR PRECIPITATION WILL QUICKLY END LATE WEDNESDAY NIGHT OR
VERY EARLY THURSDAY MORNING. AS THIS OCCURS, THERE WILL BE
CLEARING AND COOLING THURSDAY. A LITTLE WRAP-AROUND COLD AIR WILL
FILTER BACK INTO THE SOUTHWESTERN KANSAS FRIDAY, AND A LITTLE
LIGHT SNOW MAY DEVELOP. LOWER 20 PERCENT CHANCES FOR LIGHT SNOW
EXIST FOR FRIDAY.
WEDNESDAY AND THURSDAY LOOK TO WARM INTO THE LOWER TO MIDDLE 40S
NORTH OF JETMORE, AND AROUND 50F DEGREES SOUTH OF THE JETMORE-DODGE
CITY AREAS. ON FRIDAY, IT WILL COOL OFF TO HIGHS IN THE 30S.
MINIMUM TEMPERATURES WILL START OUT COLD SATURDAY MORNING, IN THE
TEENS OVER THE SNOW PACKED AREAS NORTHWEST OF A WAKEENEY TO GARDEN
CITY TO ELKHART LINE, AND RANGE TO THE MID 20S IN THE COLDWATER AND
MEDICINE LODGE AREAS. MEDIUM RANGE MODELS WARM MINIMUMS TO AROUND
THE 20F DEGREE MARK IN THE SCOTT CITY AREA BY TUESDAY, AND TO NEAR
30F DEGREES IN THE PRATT AREA. THE SLIGHT WARMING TREND WILL EXTEND
INTO THURSDAY MORNING, WITH LOWS FROM THE MID 20S IN SYRACUSE AND
SCOTT CITY, RANGING TO THE LOWER 30S IN PRATT, KIOWA AND COLDWATER.
MINIMUMS FRIDAY WILL TURN COOLER FROM AROUND 20F DEGREES IN THE KEARNY
COUNTY AREA TO THE UPPER 20S IN THE BARBER COUNTY AREA. SATURDAY
MORNING (DAY 8) SHOULD BE EVEN COLDER.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SATURDAY NIGHT)
ISSUED AT 1100 PM CST FRI JAN 4 2013
VFR CONDITIONS ARE EXPECTED TO CONTINUE AT ALL TAF SITES
OVERNIGHT. HOWEVER, LIGHT SOUTHERLY WINDS AND HIGH RELATIVE
HUMIDITIES MAY ALLOW FOR THE DEVELOPMENT OF LOW LEVEL STRATUS
AROUND DAYBREAK FROM THE TEXAS PANHANDLE NORTHWARD INTO PORTIONS
OF SOUTHWEST KANSAS...POTENTIALLY AFFECTING KDDC AND KGCK.
MVFR/IFR CIGS AND VSBYS MAY BE POSSIBLE BRIEFLY AT KDDC...AND
ALTHOUGH LESS LIKELY...KGCK GENERALLY AFTER 10Z TO 12Z. OTHERWISE,
VFR CONDITIONS WILL DOMINATE THROUGH THE DAY SATURDAY. AS FOR
WINDS, A SURFACE TROUGH OF LOW PRESSURE IN EASTERN COLORADO WILL
EDGE SLOWLY EASTWARD ACROSS WESTERN KANSAS EARLY SATURDAY MORNING.
THIS WILL RESULT IN LIGHT SOUTHWESTERLY WINDS BECOMING
NORTHWESTERLY 10 TO 20KT BY SATURDAY EARLY AFTERNOON.
&&
.PRELIMINARY POINT TEMPS/POPS...
DDC 16 38 16 43 / 0 0 0 0
GCK 14 36 13 42 / 0 0 0 0
EHA 14 41 16 45 / 0 0 0 0
LBL 16 39 14 45 / 10 0 0 0
HYS 15 35 16 37 / 0 0 0 0
P28 25 42 20 44 / 10 0 0 0
&&
.DDC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...GERARD
SHORT TERM...GERARD
LONG TERM...BURKE
AVIATION...JJOHNSON
AREA FORECAST DISCUSSION
NWS DULUTH MN
301 AM CST SAT JAN 5 2013
.SHORT TERM...TODAY THROUGH SUNDAY.
A WEAK SURFACE LOW PRESSURE SYSTEM OVER NORTH DAKOTA WILL SLIDE
EASTWARD OVER NORTHERN MINNESOTA AND NORTHERN WISCONSIN TODAY. THIS
WILL BRING A SLIGHT CHANCE OF LIGHT SNOW THIS AFTERNOON AND EVENING
TO THE NORTHLAND. LITTLE IF ANY SNOW ACCUMULATIONS WILL OCCUR WITH
THIS SYSTEM. THE ONLY EXCEPTION WILL BE THE BAYFIELD PENINSULA AND
GOGEBIC RANGE WHERE LAKE EFFECT SNOWS WILL BEGIN ONCE THE LOW MOVES
TO THE EAST OVER THE EASTERN GREAT LAKES LATE SATURDAY NIGHT. THE
LAKE EFFECT SNOW SHOWERS WILL BEGIN TO TAPER OFF SUNDAY AS HIGH
PRESSURE BUILDS IN FROM THE CENTRAL PLAINS. SNOW ACCUMULATIONS FOR
THE BAYFIELD PENINSULA AND GOGEBIC RANGE WILL BE ONE TO TWO INCHES
WITH MOST OF THAT FALLING BETWEEN 06Z AND 12Z ON SUNDAY. HIGH
TEMPERATURES WILL AVERAGE SLIGHTLY ABOVE NORMAL OVER THE
WEEKEND...MAINLY IN THE LOWER TO MID 20`S.
.LONG TERM...SUNDAY NIGHT THROUGH FRIDAY.
A STRONG AREA OF LOW PRESSURE WILL MOVE THROUGH SOUTH CENTRAL CANADA
JUST N OF THE INTERNATIONAL BORDER SUNDAY NIGHT THROUGH MONDAY
NIGHT. DUE TO THE TRACK OF THIS LOW...DO NOT EXPECT ANY SNOW OVER
THE NORTHERN TIER OF THE FA NEXT TO CANADA. WITH THE TIGHTENING
PRESSURE GRADIENT...THE WIND SPEED WILL INCREASE AND BE QUITE BRISK
ON MONDAY. THE WIND SHOULD DIMINISH MONDAY NIGHT HOWEVER AS THE
CANADIAN SFC LOW MOVES QUICKLY TO THE E. HIGH PRESSURE COVERS THE
AREA ON TUESDAY. BY TUESDAY NIGHT...THE MODELS DIVERGE WITH THE NEXT
AREA OF LOW PRESSURE. GFS TAKES THE LOW RIGHT THROUGH THE FA...ECMWF
IS WAY UP IN CANADA...THE GEM BARELY HAS A LOW CENTER SLOWLY MOVING
THROUGH MANITOBA. USED A BLENDED APPROACH WITH SMALL CHANCE POPS
TUESDAY NIGHT AND WEDNESDAY. THE MODELS GROW FARTHER APART WITH TIME
FOR THE REMAINDER OF THE LONG TERM AND USED A BLENDED APPROACH FOR
POPS/WEATHER.
&&
.AVIATION...06Z TAFS
MOST OF THE MVFR CEILINGS OVER FAR NORTHEAST MINNESOTA HAVE
DIMINISHED THIS EVENING...WITH MORE OVER FAR NORTH CENTRAL
WISCONSIN/UPPER MICHIGAN. SOME FOG AND IFR CEILINGS HAVE DEVELOPED
AS WELL...AND WE DID ADD VSBY REDUCTIONS AND IFR CEILINGS IN SOME
OF THE TAFS...PARTICULARLY KHIB. WE HAVE YET TO SEE MUCH LOWER
CLOUD DEVELOPMENT LATE THIS EVENING OUTSIDE OF THE SPOTTY IFR
CONDITIONS...AND THE RAP SEEMS TO BE HANDLING CLOUDS BETTER THAN
THE HRRR. AS LOW LEVEL WAA STRENGTHENS OVERNIGHT...WE STILL MAY
SEE SOME DEVELOPMENT LATE EXPANDING INTO SATURDAY. THE LOW IS
STILL FORECAST TO TRACK ACROSS CENTRAL-NORTHERN MINNESOTA
SATURDAY INTO UPPER MICHIGAN BY 00Z SUN. WE KEPT THE TAFS DRY
UNTIL 00Z...THEN IT APPEARS ENOUGH SATURATION WILL OCCUR TO GET
SOME LIGHT SNOW/FLURRIES. MORE SUBSTANTIAL SNOW SHOWERS WILL OCCUR
ALONG THE SOUTH SHORE DUE TO NORTHERLY WINDS FLOWING OVER THE
LAKE.
&&
.POINT TEMPS/POPS...
DLH 23 9 22 11 / 20 20 0 0
INL 20 -1 18 12 / 10 10 0 0
BRD 20 3 20 11 / 20 10 0 0
HYR 24 12 24 11 / 20 30 10 0
ASX 27 17 26 15 / 20 30 10 0
&&
.DLH WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
LS...NONE.
&&
$$
SHORT TERM...KK
LONG TERM....GSF
AVIATION...MELDE
AREA FORECAST DISCUSSION
NWS DULUTH MN
1123 PM CST FRI JAN 4 2013
.AVIATION...06Z TAFS
MOST OF THE MVFR CEILINGS OVER FAR NORTHEAST MINNESOTA HAVE
DIMINISHED THIS EVENING...WITH MORE OVER FAR NORTH CENTRAL
WISCONSIN/UPPER MICHIGAN. SOME FOG AND IFR CEILINGS HAVE DEVELOPED
AS WELL...AND WE DID ADD VSBY REDUCTIONS AND IFR CEILINGS IN SOME
OF THE TAFS...PARTICULARLY KHIB. WE HAVE YET TO SEE MUCH LOWER
CLOUD DEVELOPMENT LATE THIS EVENING OUTSIDE OF THE SPOTTY IFR
CONDITIONS...AND THE RAP SEEMS TO BE HANDLING CLOUDS BETTER THAN
THE HRRR. AS LOW LEVEL WAA STRENGTHENS OVERNIGHT...WE STILL MAY
SEE SOME DEVELOPMENT LATE EXPANDING INTO SATURDAY. THE LOW IS
STILL FORECAST TO TRACK ACROSS CENTRAL-NORTHERN MINNESOTA
SATURDAY INTO UPPER MICHIGAN BY 00Z SUN. WE KEPT THE TAFS DRY
UNTIL 00Z...THEN IT APPEARS ENOUGH SATURATION WILL OCCUR TO GET
SOME LIGHT SNOW/FLURRIES. MORE SUBSTANTIAL SNOW SHOWERS WILL OCCUR
ALONG THE SOUTH SHORE DUE TO NORTHERLY WINDS FLOWING OVER THE
LAKE.
&&
.PREV DISCUSSION... /ISSUED 823 PM CST FRI JAN 4 2013/
UPDATE...
TEMPS HAVING BEEN DROPPING QUICKLY IN SPOTS...AND ADJUSTED MINS
TONIGHT DOWN A FEW DEGREES IN SPOTS. SOME PATCHY FOG ALSO
OCCURRING AND WE ADDED SOME TO THE GRIDS. WE DON`T EXPECT THE FOG
TO BE TOO WIDESPREAD OR DENSE.
PREV DISCUSSION... /ISSUED 551 PM CST FRI JAN 4 2013/
AVIATION...00Z TAFS
MAIN CONCERN REVOLVES AROUND THE MVFR CEILINGS OVER FAR NORTHEAST
MINNESOTA...AND THE POSSIBLE DEVELOPMENT OR REDEVELOPMENT FURTHER
SOUTH LATER TONIGHT INTO SATURDAY.
THE RAP SUGGESTS THE MVFR CEILINGS OVER FAR NORTHEAST MINNESOTA
WILL REMAIN THERE OR MOVE OFF TO THE EAST. INCREASING WAA
OVERNIGHT RESULTS IN THE MODELS INCREASING LOW LEVEL RH OVER OUR
SOUTHERN CWA SHORTLY AFTER 06Z...THEN FURTHER NORTH LATE TONIGHT
INTO SATURDAY. NO EVIDENCE OF THIS YET...BUT WAA WILL BE RAMPING
UP. WE DID ADD A TEMPO GROUP TO SEVERAL TAFS TONIGHT...AND DID GO
WITH PREVAILING MVFR CEILINGS IN MOST TAFS AT SOME POINT SATURDAY.
LOW PRESSURE WILL MOVE INTO THE RED RIVER VALLEY BY 12Z...THEN
CONTINUE EAST TOWARD LAKE SUPERIOR BY MID DAY...THEN INTO UPPER
MICHIGAN BY SATURDAY EVENING. SOME LIGHT SNOW OR FLURRIES WILL
ALSO BE POSSIBLE...BUT MOST MODELS SUGGEST THEY MAY NOT OCCUR
UNTIL LATE IN THE PERIOD OR SATURDAY EVENING SO WE DID NOT ADD TO
THE TAFS YET.
SOME LIGHT FOG MAY ALSO BE CONCERN LATER TONIGHT INTO SATURDAY MORNING...AND
WE DID ADD SOME 3-6SM VSBY RESTRICTIONS.
PREV DISCUSSION... /ISSUED 348 PM CST FRI JAN 4 2013/
SHORT TERM...TONIGHT THROUGH SATURDAY NIGHT...
COOLER AIR WILL GRADUALLY FILTER INTO MUCH OF THE NORTHLAND
OVERNIGHT AS DIFFUSE FRONTAL ZONE CONTINUES TO SAG SOUTHWARD WITH
WINDS GRADUALLY TURNING TO THE N/NE. LOCALLY GUSTY WINDS ALONG THE
NORTH SHORE WILL SUBSIDE THIS EVENING AS PRESSURE RISE CENTER
MOVES OFF TO THE EAST OF THE REGION.
NEXT UPSTREAM WAVE IS CLEARLY EVIDENT IN WV IMAGERY COMING EAST OF
THE CANADIAN ROCKIES..AND ASSOCIATED WEAK SFC LOW TAKING SHAPE
OVER SRN SASKATCHEWAN. THIS WAVE WILL STEADILY MOVE ESEWD TOWARD
THE NORTHLAND TONIGHT AND SATURDAY WITH A SLOW BUT STEADY INCREASE
IN CLOUD COVER LATE TONIGHT AND THE FIRST PART OF THE DAY
SATURDAY. OVERALL..LIFT WITH THIS WAVE WILL BE RELATIVELY BENIGN
AND ACHIEVING DEEP LAYER SATURATION FOR MORE THAN A FEW HOURS LATE
SAT/SAT NIGHT WILL LIKELY BE AN ISSUE IN MOST AREAS. THUS..OVERALL
SNOW CHANCES DONT APPEAR TO BE ALL THAT ROBUST. HOWEVER..MOST
SHORT RANGE GUIDANCE MASS FIELDS ARE IN AGREEMENT THAT LOW LEVEL
WARM ADVECTION WILL BE FAIRLY STRONG..AND AIDED BY MODEST AND
SHALLOW FRONTOGENESIS FOR AT LEAST SEVERAL HOURS OVER ERN MN/NW WI
AND LK SUPERIOR. WE WILL NEED TO WATCH THIS AS THERE COULD BE A
BAND OF LIGHT SNOW THAT SETS UP SOMEWHERE FROM NEAR DULUTH EAST
TOWARD THE U.P. OF MICHIGAN..AND IF THIS OCCURS THERE COULD BE AN
INCH OR TWO OF SNOW OVER A SMALL AREA OF THE ERN CWA BY SUNDAY
MORNING.
THIS WAVE WILL TRAVERSE THE AREA RATHER QUICKLY..FOLLOWED BY COLD
ADVECTION AND AT LEAST A SHORT PERIOD OF LK EFFECT SNOW POTENTIAL
ON THE SOUTH SHORE BEGINNING SAT EVENING INTO SUNDAY. RIGHT NOW IT
APPEARS THAT ACCUMS WILL BE RELATIVELY LIGHT ALONG THE SOUTH
SHORE..BUT WE DID INCREASE POPS INTO THE 60-80 PERCENT RANGE FOR
THE BAYFIELD PENINSULA AND GOGEBIC RANGE FOR SAT NIGHT.
LONG TERM...SUNDAY THROUGH THURSDAY...
THE PERIOD WILL BEGIN WITH THE NORTHLAND IN THE WAKE OF A SURFACE
LOW PRESSURE SYSTEM...WHICH SHOULD BE IN MAINLAND MICHIGAN...AND
SURFACE HIGH PRESSURE IN THE NORTHERN PLAINS BEGINNING TO MOVE
INTO THE FA. THE NORTHERLY WINDS OVER WESTERN LAKE SUPERIOR COULD
RESULT IN LINGERING LAKE EFFECT SNOW FOR THE SOUTH SHORE SUNDAY
MORNING...BUT IT SHOULD CEASE BY THE AFTERNOON DUE TO THE CHANGING
WIND DIRECTION. AFTER THE HIGH PRESSURE MOVES IN...THE NORTHLAND
IS GOING TO HAVE A TOUGH TIME GETTING PCPN FOR A FEW DAYS. IT
LOOKS LIKE A LOW PRESSURE SYSTEM WILL MOVE THROUGH
CENTRAL/NORTHERN MANITOBA AND ONTARIO EARLY NEXT WEEK...BUT IT
WILL PROBABLY BE TOO FAR AWAY TO BRING ANY MEASURABLE PCPN TO THE
FA. THE MODELS HAVE BEEN INDICATING A POTENT MID/UPPER LEVEL LOW
CUTTING ACROSS THE SOUTHWESTERN US THIS WEEKEND AND LIFTING INTO
THE UPPER MIDWEST MID TO LATE NEXT WEEK. MOST OF THE MODELS KEEP
THE ASSOCIATED SURFACE LOW WELL ENOUGH EAST OF THE FA TO PREVENT
THE NORTHLAND FROM BEING AFFECTED BY THE SYSTEM...WITH THE
EXCEPTION OF THE ECMWF. THE ECMWF LIFTS THE SURFACE LOW INTO
CENTRAL/EASTERN WISCONSIN...AND BRINGS CONSIDERABLE PCPN TO THE SE
FA. CONSIDERING THE ECMWF HAS TEMPERATURES NEAR OR SLIGHTLY BELOW
FREEZING IN NW WISCONSIN...FORECASTED A CHANCE OF A MIXTURE OF
RAIN AND SNOW. WILL NEED TO KEEP A CLOSE EYE ON THE MODELS TO SEE
HOW THIS SYSTEM WILL AFFECT THE NORTHLAND. TEMPERATURES THROUGH
THE PERIOD SHOULD BE NEAR OR ABOVE NORMAL.
&&
.POINT TEMPS/POPS...
DLH 13 23 9 22 / 0 20 20 0
INL -5 20 -1 18 / 10 10 10 0
BRD 7 20 3 20 / 0 20 10 0
HYR 8 24 12 24 / 0 20 30 10
ASX 10 26 17 26 / 0 20 30 10
&&
.DLH WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
LS...NONE.
&&
$$
SHORT TERM...MELDE/MILLER
AVIATION.....MELDE
AREA FORECAST DISCUSSION
NWS BUFFALO NY
401 AM EST SAT JAN 5 2013
.SYNOPSIS...
HIGH PRESSURE WILL BRING FAIR WEATHER FOR MOST TODAY...BEFORE AN
AREA OF LOW PRESSURE MOVES THROUGH THE GREAT LAKES TONIGHT AND
SUNDAY WITH A WIDESPREAD LIGHT SNOWFALL. ANOTHER HIGH WILL BUILD IN
BEHIND THE LOW MONDAY...WITH A CHILLY START TO THE WEEK. AS THIS
HIGH MOVES INTO THE ATLANTIC...TEMPERATURES WILL WARM THROUGH
MID-WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
TODAYS WEATHER WILL BE MUCH LESS EVENTFUL...AS HIGH PRESSURE PASSES
NORTH OF THE REGION. A WEAK FRONTAL BOUNDARY WILL DROP SOUTHWARD TO LAKE
ONTARIO...BUT THEN STALL AND EVENTUALLY LIFT BACK NORTH LATER TODAY.
THROUGH 400 AM...THERE ARE LIGHT LAKE EFFECT SNOW SHOWERS
LINGERING EAST OF LAKE ONTARIO...BUT NO ACTIVITY OFF LAKE ERIE.
THERE ARE ALSO A FEW SNOW SHOWERS WITH THE FRONT ITSELF.
OTHERWISE...SKIES WHERE CLOUDY ACROSS MOST OF THE REGION...WITH
JUST A FEW BREAKS. THIS IS A BIT MORE PESSIMISTIC THAN PREVIOUS
GUIDANCE. THIS COMBINED WITH THE WINDS HAS KEPT TEMPERATURES FROM
DROPPING...ESPECIALLY EAST OF LAKE ONTARIO WHICH IS JUST ON THE
WARM SIDE OF THE FRONT. COLDER TEMPERATURES SHOULD MAKE IT INTO
THE NORTH COUNTRY EARLY THIS MORNING...WITH ELSEWHERE LIKELY TO
REMAIN IN THE MID AND UPPER 20S DUE TO THE CLOUD COVER.
WHAT IS LEFT OF THE LAKE EFFECT SNOW SHOWERS WILL SLIDE SOUTH AND
DISSIPATE THROUGH MID-MORNING. THE FRONT MAY PROVIDE A BRIEF
ENHANCEMENT...BUT ALL OF THIS SHOULD BE ON THE LITE SIDE...WITH
LITTLE IF ANY SNOW ACCUMULATION THROUGH THIS MORNING. THE HRRR MODEL
HAS A GOOD MODEL ON THESE TRENDS...AND IS GENERALLY SUPPORTED BY THE
RGEM/NAM IN QPF FORECASTS.
OTHERWISE...EXPECT FAIR WEATHER TODAY...WITH SOME BREAKS OF SUN...ESPECIALLY
EAST OF LAKE ONTARIO WHICH WILL BE NORTH OF THE FRONTAL BOUNDARY.
CLOUDS SHOULD LINGER LONGEST IN THE SOUTHERN TIER...AND ALONG THE
FRONTAL BOUNDARY. TEMPERATURES SHOULD BE SEASONABLE...WITH HIGHS
IN THE LOWER 30S IN MOST LOCATIONS...MID TO UPPER 20S IN THE
EASTERN LAKE ONTARIO REGION.
FOR TONIGHT...A WEAK ARE OF LOW PRESSURE WILL MOVE ACROSS THE UPPER
LAKES. THIS WILL SWING A WEAK AREA OF WARM AIR ADVECTION IN THE
MID-LEVELS...AS AN UPPER TROF AXIS QUICKLY CROSSES THE REGION.
BUFKIT SHOWS LIFT BOTH IN THE MID AND UPPER LEVELS...SUGGESTING EACH
FEATURE WILL MAKE A CONTRIBUTION. LAKES MAY PROVIDE A MINIMAL
MOISTURE CONTRIBUTION...BUT THIS WILL LARGELY BE A SYNOPTIC EVENT.
DESPITE MODEST QPF VALUES...AVERAGING A TENTH OF AN INCH OR
LESS...THERE IS BROAD MODEL AGREEMENT THAT THERE WILL BE SOME
MEASURABLE PRECIPITATION ACROSS MOST OF THE CWA. BECAUSE OF
THIS...GENERALLY GO WITH CATEGORICAL POPS...DESPITE THE MODEST
AMOUNTS OF QPF.
ITS INTERESTING TO NOTE THAT DESPITE THE MARGINALLY COLD
TEMPERATURES AT THE SURFACE...OMEGA LINES UP FAIRLY WELL WITH SNOW
GROWTH REGIONS WHICH SUGGESTS FAIRLY DECENT SNOW RATIOS. THIS
SAID...THE QUICK PROGRESSION OF THE SHORTWAVE...AND MODEST WARM AIR
ADVECTION SUPPORT LIGHT QPFS WHICH ARE THE MODEL CONSENSUS. GIVEN
SUCH LIGHT QPF...SNOW RATIO WILL NOT HAVE MUCH OF AN IMPACT ON
AMOUNTS. FOR MOST AREAS EXPECT AROUND AN INCH OF SNOW TONIGHT...WITH
LESSER AMOUNTS INLAND ACROSS ALLEGANY/LIVINGSTON/ONTARIO COUNTIES.
SNOW SHOULD MOVE INTO THE REGION LATE THIS EVENING...AND BRING A
RATHER QUICK 3 TO 6 HOUR PERIOD OF LIGHT SNOW.
OVERNIGHT LOWS SHOULD COME DURING THE EVENING HOURS...WITH
TEMPERATURES RISING LATER IN THE NIGHT AS WARMER AIR AND CLOUDS
ADVECT INTO THE REGION.
&&
.SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/...
TWO SHORTWAVES WILL IMPACT THE REGION SUNDAY...PRODUCING LIGHT
SNOWFALL ACROSS THE REGION. THE FIRST SHORTWAVE CROSSING THE EASTERN
GREAT LAKES FROM THE SOUTHWEST WILL BE IN THE PROCESS OF CROSSING
THE REGION SUNDAY MORNING WITH SNOWFALL FOCUSED EAST OF THE GENESEE
VALLEY.
THE SECOND SHORTWAVE...THIS IN THE NORTHERN BRANCH OF THE JET STREAM
WILL SLIGHTLY DEEPEN A SURFACE LOW ACROSS THE SOUTHERN ONTARIO
CANADA REGION SUNDAY. A SOUTHWEST FLOW AHEAD OF THE LOW AND ITS
ASSOCIATED COLD FRONT...WITH 925 HPA TEMPERATURES AROUND -3 TO -4C
WILL CREATE JUST ENOUGH LAKE INSTABILITY THAT A LITTLE LAKE ENHANCED
SNOW SHOWERS ARE LIKELY AHEAD OF THE COLD FRONT. LOW LEVEL LIFT IS
MARGINAL...BUT IT SHOULD SUFFICE TO BRING MOISTURE UP INTO THE
BOTTOM OF THE GOOD SNOW GROWTH ZONE LATER IN THE DAY SUNDAY.
OFF BOTH LAKE ERIE AND ONTARIO WINDS WILL BACK ENOUGH AHEAD OF THE
COLD FRONT TO ALLOW THE LAKE ENHANCED SNOW SHOWERS TO BEGIN AROUND
BUFFALO AND THE NORTHTOWNS OFF LAKE ERIE...AND WATERTOWN AND TOWNS
NORTH OFF LAKE ONTARIO. WHILE SYNOPTIC SNOW IS LIKELY ACROSS MUCH OF
THE REGION SUNDAY NIGHT AHEAD OF THE COLD FRONT...WILL FOCUS THE
HIGHEST POPS WITHIN A BAND OF LAKE ENHANCED SNOW SHOWERS THAT WILL
QUICKLY DROP SOUTHWARD OFF BOTH LAKES THROUGH THE AFTERNOON AND
EARLY EVENING HOURS.
THE COMBINATION OF LAKE SNOWS AND SYNOPTIC SNOWS WILL QUICKLY END
THROUGH THE OVERNIGHT HOURS AS DRIER AIR USHERS IN BEHIND THE COLD
FRONT THAT CROSSES MUCH OF THE CWA SUNDAY NIGHT. LAKE ENHANCED SNOW
WILL END FIRST OFF LAKE ERIE...AND LATER IN THE NIGHT OFF LAKE
ONTARIO WITH JUST A FLURRY LINGERING TOWARDS DAWN SOUTH AND EAST OF
LAKE ONTARIO.
AS FAR AS SNOWFALL GOES SUNDAY AND SUNDAY NIGHT AREAS EAST OF LAKE
ONTARIO WILL LIKELY RECEIVED THE GREATEST SNOW TOTALS OF 2 TO 4
INCHES...WITH EARLY MORNING SYNOPTIC SNOW...AND THEN LATER IN THE
AFTERNOON SOME LAKE ENHANCED SNOW SHOWERS IN ADDITION TO A LIGHT
SYNOPTIC SNOWFALL AHEAD OF THE COLD FRONT. SOUTH OF LAKE ONTARIO
SNOWFALL SUNDAY AND SUNDAY EVENING WILL LIKELY AVERAGE A HALF TO ONE
INCH WITH THE HIGHER TERRAIN SOUTH OF BUFFALO POSSIBLY NEARING 2
INCHES.
TEMPERATURES ON SUNDAY WILL CLIMB TO THE LOW TO MID 30S ACROSS THE
REGION BEFORE FALLING BACK TO SEASONAL NORMALS SUNDAY NIGHT BEHIND
THE COLD FRONT. A NORTHWEST FLOW WILL LIKELY MAINTAIN CLOUDS ACROSS
MUCH OF THE AREA SOUTH OF LAKE ONTARIO WITH ONLY PARTIAL CLEARING
LATE ACROSS THE NORTHERN NIAGARA FRONTIER AND NORTHERN GENESEE
VALLEY. TOWARDS THE NORTH COUNTRY SOME CLEARING IS LIKELY TO THE
NORTH AND WEST OF THE TUG HILL AND WESTERN FOOT HILLS OF THE
ADIRONDACKS...AND HERE WE COULD SEE TEMPERATURES DROP LATE IN THE
NIGHT TOWARDS THE LOW SINGLE DIGITS.
MONDAY MORNING THE TAIL END OF THE COLD FRONT WILL STALL ACROSS
CENTRAL NEW YORK WITH SOME PATCHES OF CLOUDS LINGERING THROUGH THE
MORNING ACROSS THE INTERIOR SOUTHERN TIER AND SOUTHERN FINGER LAKES.
THIS TRAILING COLD FRONT WILL SEPARATE TWO AREAS OF HIGH
PRESSURE...ONE OVER QUEBEC...AND A SECOND OVER THE OHIO VALLEY.
THESE TWO AIRMASSES...COMBINED WITH THE PASSING OF AN UPPER LEVEL
RIDGE AXIS SHOULD GIVE A QUIET DAY TO THE REGION MONDAY WITH MOST
AREAS MOSTLY SUNNY BY AFTERNOON. STILL ON THE CHILLY SIDE MONDAY
EVEN WITH PLENTY OF SUNSHINE AS HIGH TEMPERATURES WILL LIKELY HOLD
IN THE 20S ACROSS MUCH OF THE REGION. THOUGH WARM AIR ADVECTION
ALOFT AND LIGHT SOUTHERLY WINDS AT THE SURFACE LOWS MONDAY
NIGHT...TEMPERATURES SHOULD DROP TO A SIMILAR VALUES AS THE
PRECEDING NIGHT AS SKIES WILL LIKELY BE MAINLY CLEAR THROUGH THE
NIGHT ALLOWING FOR ADDITIONAL AMOUNTS OF RADIATIONAL COOLING.
OVERNIGHT LOWS WILL DROP BACK INTO THE TEENS...WHILE THE NORTH
COUNTRY WILL LIKELY AGAIN DROP INTO THE SINGLE DIGITS.
&&
.LONG TERM /TUESDAY THROUGH FRIDAY/...
A GENERAL ZONAL FLOW IS FORECAST TO BE IN PLACE ALONG THE
CANADIAN/US BORDER TUESDAY AND WEDNESDAY...WHILE A CLOSED LOW LIFTS
OUT OF THE SOUTHWEST PART OF THE COUNTRY. THE GFS AND ECMWF STILL
HAVE SIGNIFICANT DISCREPANCIES IN THE WAY THEY HANDLE THIS CUTOFF
LOW. THE ECWMF KEEPS THE LOW OVER THE SOUTHERN PLAINS THROUGH
WEDNESDAY...BEFORE LIFTING IT OUT INTO THE MIDWEST ON
THURSDAY...WHILE THE GFS LIFTS THE LOW OUT ON WEDNESDAY AND TRACKS
AN OPEN WAVE TOWARD THE LOWER LAKE ON THURSDAY. FOR NOW...WILL
CONTINUE TO HPC GUIDANCE WHICH SEEMS TO FAVOR THE MORE CONSERVATIVE
ECMWF SOLUTION. BASED ON THIS GUIDANCE...WILL KEEP THE AREA DRY
THROUGH WEDNESDAY NIGHT AS THE SURFACE LOW THAT WILL BE ASSOCIATED
WITH THE CLOSED STAYS WELL TO OUR WEST.
THE ECMWF LIFTS THE CLOSED LOW INTO THE MIDWEST ON THURSDAY...THEN
OPEN THE WAVE UP ON FRIDAY AS IT TRACKS IT EAST ACROSS THE LOWER
LAKES. THE CORRESPONDING SURFACE LOW IS FORECAST TO HEAD NORTHEAST
TOWARD THE CENTRAL GREAT LAKES ON THURSDAY...BEFORE TRACKING NORTH
OF LAKE ONTARIO ON FRIDAY. THE DEEP LAYERED SOUTHERLY FLOW AHEAD OF
THIS SYSTEM WILL TRANSPORT MILDER AIR NORTH TOWARD OUR AREA. WHILE
TEMPERATURES ALOFT LOOK WARM ENOUGH TO SUPPORT MAINLY RAIN...SURFACE
TEMPERATURES WILL BE THE KEY TO THE PCPN TYPE. BASED ON FORECAST
TEMPERATURES...WE MAY SEE A MIX OF FROZEN PCPN THURSDAY MORNING
BEFORE TEMPERATURES WARM UP ENOUGH FOR A POSSIBLE CHANGEOVER TO ALL
RAIN DURING THE AFTERNOON. MIXED PCPN COULD SET UP AGAIN ACROSS THE
HIGHER ELEVATIONS THURSDAY NIGHT BEFORE ALL PCPN CHANGES BACK OVER
TO RAIN ON FRIDAY. FOR NOW WILL KEEP FORECAST AS RAIN AND SNOW...AND
FINE TUNE THE MIXED PRECIPITATION OF SLEET AND FREEZING RAIN AS WE
DRAW CLOSER TO THE EVENT. STAY TUNED TO LATER MODEL RUNS WHICH WILL
HELP TO FINE TUNE THIS POTENTIAL FOR MIXED PCPN.
REGARDING TEMPERATURES...EXPECT A MODERATING TREND THAT WILL SEE
DAYTIME HIGHS RISING INTO THE UPPER 30S/LOWER 40S ON WEDNESDAY AND
THURSDAY...AND MAYBE EVEN THE LOW/MID 40S ON FRIDAY.
&&
.AVIATION /09Z SATURDAY THROUGH WEDNESDAY/...
WINDS HAVE DIMINISHED ACROSS THE REGION...WHICH END THE BLOWING AND
DRIFTING SNOW. AT 09Z...MOST TAF LOCATIONS WERE VFR...AS A DRIER AIR
AND A LIFTING INVERSION HAS ALLOWED CIGS TO LIFT. THERE MAY BE
PERIODS OF MVFR CIGS AT BUF/IAG/ROC...OTHERWISE MAINLY VFR CONDITIONS
ARE LIKELY FOR TODAY. A LOWER CLOUD DECK WILL LINGER AT JHW...LIKELY
INTO THE MORNING HOURS BEFORE LIFTING AND SCATTERING.
FOR TONIGHT...EXPECT A PERIOD OF GENERALLY LIGHT SNOWFALL TO BRIEFLY
RESULT IN IFR CONDITIONS DUE TO VSBY IN THE 1 TO 2 SM RANGE.
ACCUMULATIONS WILL BE LIGHT.
OUTLOOK...
SUNDAY...MVFR/IFR WITH CHANCE OF SNOW SHOWERS.
MONDAY AND TUESDAY...VFR.
WEDNESDAY...VFR/MVFR WITH A CHANCE OF RAIN.
&&
.MARINE...
WINDS HAVE DROPPED IN THE LAST SEVERAL HOURS...WITH A CONTINUED
DIMINISHING TREND EXPECTED THROUGH TODAY. SMALL CRAFT ADVISORIES ARE
IN PLACE ACROSS MOST OF THE WATERS...BUT THESE SHOULD BE ABLE TO BE
DROPPED LATER THIS MORNING.
AFTER THIS...EXPECT A RELATIVELY QUIET PERIOD ON THE WATERS...WITH
NO MAJOR SYSTEMS FORECAST THROUGH THE MIDDLE OF NEXT WEEK. THIS
SAID...THERE WILL BE SEVERAL OPPORTUNITIES FOR SMALL CRAFT
ADVISORIES...DEPENDING ON WIND DIRECTION AND STRENGTH.
&&
.BUF WATCHES/WARNINGS/ADVISORIES...
NY...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 10 AM EST THIS MORNING FOR LEZ040-
041.
SMALL CRAFT ADVISORY UNTIL 10 AM EST THIS MORNING FOR
LOZ042-043.
SMALL CRAFT ADVISORY UNTIL NOON EST TODAY FOR LOZ044-045.
&&
$$
SYNOPSIS...APFFEL
NEAR TERM...APFFEL
SHORT TERM...THOMAS
LONG TERM...THOMAS/TJP
AVIATION...APFFEL
MARINE...APFFEL/THOMAS
AREA FORECAST DISCUSSION
NWS CHARLESTON WV
1223 AM EST SAT JAN 5 2013
.SYNOPSIS...
SURFACE HIGH PRESSURE TONIGHT. TWO MID/UPPER LEVEL TROUGHS PASS THIS
WEEKEND. HIGH PRESSURE THEN BUILDS IN...MONDAY AND EARLY WEDNESDAY.
LOW PRESSURE BRINGS RAIN SHOWERS LATE WEDNESDAY NIGHT AND THURSDAY.
&&
.NEAR TERM /THROUGH TODAY/...
1215AM UPDATE... STILL SOME LINGERING CLOUDS ACROSS NORTHERN
MOUNTAINOUS COUNTIES...WHICH WILL GRADUALLY DISSIPATE THROUGH THE
REST OF THE NIGHT. LOOKS LIKE SNOWSHOE MAY ALREADY BE STARTING ITS
NON-DIURNAL TREND AS 850 WAA TAKES OVER...SO MADE SOME MINOR
TWEAKS TO GO WITH SLOW WARMING THERE.
PREVIOUS DISCUSSION...
USED RAP AND VIS SAT TRENDS AS BASE FOR TIMING IMPROVING SKY
CONDITION INTO TONIGHT. THINK AREAS ALONG AND E OF I79 CORRIDOR
WILL KEEP CLDS WITH N MTNS HOLDING ON UNTIL PERHAPS 15Z. LOWS
TONIGHT TRICKY ONCE AGAIN AND WILL DEPEND ON EXTENT OF CLEARING
AND BL PUFF. LAMP GUIDANCE CONT TO BE ON WARM SIDE...LKLY OWING TO
BL PUFF AND ALSO CLDS ACROSS THE MTNS. DEEPER VALLEYS/HOLLOWS MAY
DECOUPLE THOUGH...GIVING UPPER TEENS. WILL LEAN TOWARD LAMP WHICH
HAS PERFORMED BETTER OVER RECENT COLD BIAS IN MET/MAV AND
INCORPORATE A COLDER SOLUTION FOR TYPICAL COLD SPOTS OUTSIDE OF
THE CLDS.
ANY REMAINING STRATUS ACROSS N MTNS WILL SCT OUT BY LATE
MORNING. SOME HIGH CLDS WILL BE ROLLING IN AFTN FROM SW...HELPING
TO PUT A FILTER ON SUNSHINE. KEPT POPS OUT THROUGH 00Z...WITH DRY
LLVLS IN PLACE. HOWEVER...MAY SEE ENOUGH TOP DOWN MOISTENING FOR
SOME LIGHT PCPN ACROSS SW VA BY 00Z.
&&
.SHORT TERM /TONIGHT THROUGH MONDAY/...
UPPER SPLIT FLOW PATTERN CONTINUES. MODELS IN GOOD AGREEMENT ON
SOUTHERN STREAM UPPER LOW OVER THE SOUTHWEST U.S. WEAKENING AS IT
OPENS UP...AND LIFTS NORTHEASTWARD ACROSS THE OHIO VALLEY SATURDAY
NIGHT IN CONFLUENT FLOW ALOFT. THIS SYSTEM IS FORECAST TO BE TOO
WEAK TO LIFT THE BAROCLINIC ZONE...STILL ACROSS THE SOUTHEASTERN
STATES...NORTHWARD ENOUGH TO AFFECT ALL BUT THE SOUTHEAST PORTION
OUR AREA. WITH THE VORT CENTER OF THE SYSTEM TRACKING ACROSS THE
MIDDLE OHIO VALLEY INTO THE GREAT LAKES...THE EFFECTS OF ITS
DYNAMICS WILL MAINLY CLIP OUR SOUTHEAST OHIO ZONES. THUS...AS A
WHOLE...OUR AREA LOOKS TO BE IN A MIN FOR QPF. WILL KEEP LOW POPS
ACROSS THE AREA SATURDAY NIGHT...WITH THE BEST CHANCE OVER THE
NORTHWEST AND SOUTHEAST AREAS. DRY SLOW MOVES IN BY SUNDAY MORNING
AS THE SOUTHERN STREAM SYSTEM DEPARTS WITH A BREAK IN THE PRECIP.
DURING SUNDAY...A NORTHERN STEAM UPPER TROUGH AND COLD FRONT DROPS
RAPIDLY SOUTHEAST ACROSS THE AREA SUNDAY AFTERNOON...BRINGING
SCATTERED RAIN SHOWERS...CHANGING TO SNOW SHOWERS BEFORE ENDING
SUNDAY NIGHT. AGAIN...EXPECT LIGHT QPF WITH ANY SNOW ACCUMULATIONS
LIMITED TO MAINLY THE NORTHERN MOUNTAINS...GENERALLY AN INCH OR TWO
BY MONDAY MORNING.
BEHIND THIS QUICK HITTER WILL BE HIGH PRESSURE FOR MONDAY WITH
INCREASING SUNSHINE. MAX TEMPERATURES SUNDAY AND MONDAY AFTERNOON
WILL BE SIMILAR IN THE LOW TO MID 40S...SUNDAY MAINLY
DUE TO THE CLOUDS AND MONDAY MAINLY DUE TO THE SUNSHINE.
&&
.LONG TERM /MONDAY NIGHT THROUGH FRIDAY/...
HIGH PRESSURE REMAINS IN CONTROL MONDAY NIGHT AND TUESDAY TO PROVIDE
DRY CONDITIONS.
A DEVELOPING LOW PRESSURE SYSTEM WILL APPROACH FROM THE WEST
WEDNESDAY NIGHT. DIFFERENCES BETWEEN THE ECMWF AND GFS EXIST. THE
ECMWF IS THE PREFERRED MODELS WITH A LOW LATITUDE CYCLONE BECOMING
LESS PROGRESSIVE...WITH SFC LOW TRACK MOVING FROM THE CENTRAL PLAINS
NORTHEAST INTO THE GREAT LAKES REGION...CONTRARY TO THE GFS THAT
DEVELOPS THE LOW OVER THE SOUTHERN PLAINS...TRACKING THE LOW
OVERHEAD WV.
THEREFORE...MINOR TWEAKS WHERE NEEDED FROM PREVIOUS FORECAST...WITH
CHANCES OF RAIN SHOWERS SPREADING FROM WEST TO EAST LATE WEDNESDAY
NIGHT...WITH THE BULK OF PCPN OCCURRING ON THURSDAY.
TEMPERATURE PROFILES AND BOUNDARY LAYER SOUTHWEST FLOW SUGGEST ALL
PCPN STARTING AS LIQUID BY 15Z THURSDAY. THEREFORE...HIGHEST POPS
WHERE CODED ON THURSDAY. ECMWF H850 STRENGTHENING SOUTH TO SOUTHWEST
FLOW AROUND 50 KNOTS...AND TEMPERATURES NEAR 11C BY 18Z
THURSDAY...SUPPORT A GRADUAL WARMING TREND THRU THURSDAY AFTERNOON.
DECREASED POPS BY 06Z FRIDAY...WITH CHANCE POPS MAINLY OVER NORTHERN
AND EASTERN MOUNTAINS. DRIER AIR MASS EXPECTED BY MID FRIDAY MORNING
WITH PCPN EXITING NORTHEAST.
WENT GENERALLY WITH HPC GUIDANCE FOR TEMPERATURES ADDING FEW LOCAL
DETAILS.
&&
.AVIATION /05Z SATURDAY THROUGH WEDNESDAY/...
JUST A SMALL PATCH OF MVFR STRATUS REMAINS ACROSS THE NORTHERN
MOUNTAINS. SO MVFR LINGERING AT KEKN THROUGH THE NIGHT WITH VFR
ELSEWHERE. CLOUDS WILL INCREASE AGAIN THIS AFTERNOON INTO
TONIGHT...WITH SOME MVFR CEILINGS POSSIBLY SNEAKING INTO THE
HIGHER TERRAIN BY THE END OF THE TAF PERIOD. ALSO POSSIBLE LIGHT
RAIN OR SNOW SHOWERS ENTERING FORECAST AREA AFTER 00Z. IN GENERAL
LOOKING AT CALM TO LIGHT SW FLOW INTO TONIGHT.
FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 06Z SUNDAY...
FORECAST CONFIDENCE: HIGH.
ALTERNATE SCENARIOS: TIMING OF BREAKUP OF CLOUDS OVER THE NORTHERN
MOUNTAINS MAY VARY.
EXPERIMENTAL TABLE OF FLIGHT CATEGORY OBJECTIVELY SHOWS CONSISTENCY
OF WFO FORECAST TO AVAILABLE MODEL INFORMATION:
H = HIGH: TAF CONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL.
M = MEDIUM: TAF HAS VARYING LEVEL OF CONSISTENCY WITH MODELS.
L = LOW: TAF INCONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL.
DATE SAT 01/05/13
UTC 1HRLY 06 07 08 09 10 11 12 13 14 15 16 17
EST 1HRLY 01 02 03 04 05 06 07 08 09 10 11 12
CRW CONSISTENCY H H H H H H H H H H H H
HTS CONSISTENCY H H H H H H H H H H H H
BKW CONSISTENCY H H H H H H H H H H H H
EKN CONSISTENCY L L L L L L L H H H H H
PKB CONSISTENCY H H H H L L L L L L L H
CKB CONSISTENCY H H L L L L L L L L L H
AFTER 06Z SUNDAY...
NO WIDESPREAD IFR CONDITIONS EXPECTED.
&&
.RLX WATCHES/WARNINGS/ADVISORIES...
WV...NONE.
OH...NONE.
KY...NONE.
VA...NONE.
&&
$$
SYNOPSIS...ARJ/JMV/30
NEAR TERM...MZ/30
SHORT TERM...JMV
LONG TERM...ARJ
AVIATION...MZ
AREA FORECAST DISCUSSION
NWS HOUSTON/GALVESTON TX
1151 PM CST FRI JAN 4 2013
.DISCUSSION...
UPDATED AVIATION DISCUSSION.
&&
.AVIATION...
CONTINUED WITH VFR FOR MOST OF THE TAF PERIOD DESPITE PERIODS OF
MAINLY LIGHT SHOWERS. BEST CHANCE FOR MEASURABLE RAIN...ALBEIT
LIGHT WILL BE OVERNIGHT FOR NORTHERN TAF SITES...AND TOMORROW FOR
SOUTHERN TAF SITES AS JET STREAK AND ASSOCIATED LIFT MOVE ACROSS
THE AREA...ALTHOUGH THERE COULD BE A LIGHT SHOWER ALMOST ANY TIME.
46
&&
.MARINE...EXTENDED SMALL CRAFT ADVISORY THROUGH TOMORROW AS NOW
APPEARS AFTER A SLIGHT DECREASE IN SPEEDS OVERNIGHT...WINDS SHOULD
PICK UP AGAIN LATE TONIGHT AND SATURDAY AS GULF LOW DEEPENS.
SHOULD BE MAINLY THE 20 TO 60 NM ZONES THAT SHOULD SEE THE HIGHER
WINDS. 46
&&
.PREV DISCUSSION... /ISSUED 915 PM CST FRI JAN 4 2013/
UPDATE...
SCATTERED OFFSHORE SHOWERS BECOMING BETTER ORGANIZED JUST OFF THE
COASTLINE...WITH VERY LIGHT SHOWER ACTIVITY JUST TO THE WEST OF
OUR NORTHWESTERN CWA. WEAK DIVERGENCE RIDING PARALLEL THE COAST
(PER REGION FALLING IN THE RR 25H QUAD) AND THE OFFSHORE STATIONARY
BOUNDARY WILL BE ENOUGH TO KEEP PERIODIC LIGHT SHOWERS IN PLAY
THROUGH SATURDAY AFTERNOON. THE NEAR WEST-TO-EAST ELONGATED UPPER
TOUGH AXIS WILL EVENTUALLY PASS EAST OF THE REGION LATE TOMORROW...
BRINGING THE INTERIOR SHRA TO AN END GOING INTO SATURDAY EVENING.
A WEAK LOWER LEVEL BOUNDARY WILL PASS INTO CENTRAL TEXAS...BUT
WITHOUT A SIGNIFICANT NORTHWESTERN HIGH TO BACK IT...THIS BOUNDARY
WILL STRETCH OUT AND SURFACE WINDS WILL REMAIN NORTHEAST IN NATURE.
MODERATE TO STRONG NORTH-EAST MARITIME WINDS THROUGH THE WEEKEND
AS THE OFFSHORE GRADIENT BETWEEN INLAND HIGH PRESSURE AND THE OFFSHORE
STATIONARY BOUNDARY STAYS TAUNT.
ALONG WITH PASSING SHOWERS...A COLD AND CLOUDY SATURDAY. ISENTROPIC
UPGLIDE IN PLACE AS MID-LEVEL SOUTHWESTERLIES ABOVE THESE NEAR SURFACE
(NORTH)EASTERLIES WILL KEEP SKIES MOSTLY OVERCAST AND THE MAJORITY
OF THE DAY IN THE 40S...MERCURY ONLY BRIEFLY TOUCHING THE LOWER 50S
FOR A LATE AFTERNOON HOUR OR TWO. 31
PREV DISCUSSION... /ISSUED 607 PM CST FRI JAN 4 2013/
DISCUSSION...
UPDATED AVIATION DISCUSSION.
AVIATION...
LATEST OBS AND RADAR SHOWING SOME LIGHT SHOWERS AROUND NORTHERN
TAF SITES WITH VFR 5000 TO 6000 FOOT DECK EVERYWHERE. SOME LOWER
CLOUDS INDICATED OFF TO THE WEST. OVERALL EXPECTING MOSTLY VFR
CONDITIONS AT TAF SITES...WITH A PERIOD OF MVFR POSSIBLE AT LEAST
NORTHERN TAF SITES OVERNIGHT AS BAND OF LIGHT RAIN SHIFTS EAST.
ANOTHER BAND OF LIGHT RAIN POSSIBLE ON SATURDAY FARTHER SOUTH AS
JET STREAK PIVOTS AROUND UPPER LOW...PLACING SE TEXAS IN RIGHT
REAR QUADRANT. IN ANY CASE NOT EXPECTING MUCH IN THE WAY OF
VISIBILITY RESTRICTIONS...JUST A SHORT PERIOD OF MVFR CIGS WITH
THESE BANDS OF RAIN AS THEY PIVOT THROUGH. 46
PREV DISCUSSION... /ISSUED 407 PM CST FRI JAN 4 2013/
DISCUSSION...
NOT TOO MANY CHANGES FOR THE SHORT TERM PART OF THE FCST WITH THIS
PACKAGE AS THE COLD/CLOUDY/WET PATTERN REMAINS IN PLACE OVER SE TX
THROUGH THE EARLY PART OF THIS WEEKEND. STRONG SOUTHERN STREAM JET
HELPING TO BRING A SERIES OF SHORTWAVES ACROSS THE REGION WITH THE
NEXT ONE LOOKING LIKE IT IS GOING TO MOVE THROUGH OUR CWA LATE TO-
NIGHT/SAT (PER LATEST THE WV LOOPS).
THE PERSISTENT BKN/OVC MID/HIGH CLOUD DECK SHOULD BREAK BY SUN AS
THE MAIN UPPER TROF AXIS SHIFTS EAST AND THE BRIEF RIDGING DEVEL-
OPS IN ITS WAKE. BUT AS IT HAS BEEN THE TREND OF LATE...THIS VERY
PROGRESSIVE UPPER PATTERN WILL BE BRINGING THE NEXT SYSTEM TOWARD
THE STATE QUICKLY. WHILE MODELS HAVE BEEN CONSISTENT WE ARE STILL
SEEING MARKED DIFFERENCES IN REGARD TO THE TIMING FOR THE PASSAGE
OF THE NEXT CLOSED UPPER LOW STORM SYSTEM. ECMWF RETAINING A LONE
WOLF ROLE WITH ITS SLOWER TIMING...WITH THE GFS APPEARING TO HAVE
SPED UP WITH THE 12Z RUNS. DID MAKE SOME CHANGES TO POPS FOR THIS
TUES/TUES NIGHT TIMEFRAME ACCOUNT FOR THE UNCERTAINTY. REGARDLESS
WE COULD BE DEALING WITH STRONG/SEVERE STORMS WITH THE PASSAGE OF
THIS SYSTEM (NO MATTER WHICH DAY IT ARRIVES). PROGS OF STRONG LOW
TO MID LEVEL INFLOW (40-50KTS)...FAVOURABLE POSITION OF THE UPPER
JET (LFQ) AND THE PASSAGE OF THE COLD FRONT ITSELF ALL SEEM TO BE
POINTING IN THAT DIRECTION. BEAR WATCH IN PLACE. 41
&&
.PRELIMINARY POINT TEMPS/POPS...
COLLEGE STATION (CLL) 45 40 51 38 57 / 40 30 20 10 10
HOUSTON (IAH) 50 40 52 39 60 / 20 30 40 10 10
GALVESTON (GLS) 48 45 54 46 59 / 20 30 40 20 10
&&
.HGX WATCHES/WARNINGS/ADVISORIES...
TX...NONE.
GM...SMALL CRAFT SHOULD EXERCISE CAUTION THROUGH SATURDAY AFTERNOON
FOR THE FOLLOWING ZONES: WATERS FROM FREEPORT TO THE
MATAGORDA SHIP CHANNEL OUT 20 NM...WATERS FROM HIGH ISLAND
TO FREEPORT OUT 20 NM.
SMALL CRAFT ADVISORY UNTIL 5 PM CST SATURDAY FOR THE FOLLOWING
ZONES: WATERS FROM FREEPORT TO THE MATAGORDA SHIP CHANNEL
20 NM TO 60 NM...WATERS FROM HIGH ISLAND TO FREEPORT 20 TO
60 NM.
&&
$$
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
1141 PM CST FRI JAN 4 2013
.SHORT TERM...TONIGHT THROUGH MONDAY
233 PM CST FRI JAN 4 2013
MAIN FORECAST CONCERNS ARE ON LIGHT PRECIPITATION CHANCES SATURDAY
AFTERNOON INTO SATURDAY NIGHT.
CURRENTLY AS OF 20Z...WATER VAPOR LOOP AND RAP 500MB HEIGHT ANALYSIS
SHOWED RIDGING ALONG THE WEST COAST OF THE U.S. INTO BRITISH
COLUMBIA...AN UPPER LOW OVER NEW MEXICO...A SHORTWAVE TROUGH OVER
SOUTHERN ALBERTA...WEAK RIDGING OVER THE DAKOTAS AND DEEP TROUGHING
OVER EASTERN CANADA. THE FORECAST AREA WAS UNDER SUBSIDENCE ALOFT
BEING IN NORTHWEST FLOW AHEAD OF THE DAKOTAS RIDGING...RESULTING IN
CLEAR SKIES. IN FACT...MAINLY CLEAR SKIES ENCOMPASS MUCH OF THE
UPPER MIDWEST DUE TO PLENTY OF DRY AIR...SEEN ON 12Z SOUNDINGS FROM
BIS...OAX...MPX AND GRB. ONE THING OF INTEREST ON ALL OF THOSE
SOUNDINGS IS A STRONG AND NEARLY SATURATED INVERSION BETWEEN
925-950MB. AGAIN...DESPITE THE NEAR SATURATION...SKIES ARE STILL
CLEAR. SUNSHINE PLUS THE 925MB TEMPS STARTING OFF IN THE -3 TO -6C
RANGE AT 12Z FROM SOUNDING DATA AND DRY AIR HAS ALLOWED TEMPERATURES
TO CLIMB INTO THE MID 20S TO LOW 30S. TO THE NORTHWEST...HIGH
CLOUDS WERE SPREADING ACROSS SASKATCHEWAN AND NORTH DAKOTA AHEAD
OF THE SOUTHERN ALBERTA SHORTWAVE TROUGH. IN ADDITION...AN AREA OF
LOW PRESSURE HAS FORMED OVER SOUTHERN SASKATCHEWAN WITH A WARM
FRONT EXTENDING SOUTHEAST TO BISMARCK NORTH DAKOTA.
TONIGHT AND SATURDAY...MODELS ARE IN GOOD AGREEMENT DROPPING THE
SHORTWAVE TROUGH OVER ALBERTA THROUGH THE NORTHERN PLAINS AND INTO
NEBRASKA BY 00Z SUNDAY. THIS TROUGH HELPS TO EJECT AND SHEAR OUT THE
NEW MEXICO UPPER LOW...WHICH GETS LIFTED INTO SOUTHERN ILLINOIS AND
INDIANA. THE TRACKS OF THESE FEATURES SPLIT THE FORECAST AREA...
HOWEVER...THERE ARE STILL CONCERNS. THE MAIN ONE IS WITH LOW LEVEL
SATURATION. 925-900MB RH PROGS FROM THE 04.12Z NAM/GFS SHOW THAT AS
THE NEW MEXICO UPPER LOW LIFTS NORTHEAST...AN AREA OF LOW STRATUS
FORMS ACROSS MISSOURI SATURDAY MORNING...WHICH THEN SPREADS INTO
EASTERN IOWA AND SOUTHERN WISCONSIN DURING THE AFTERNOON. ABOVE
900MB...TROPOSPHERE IS STILL PRETTY DRY. ANALYSIS LOOKING AT THE
275-280K SURFACES SHOWS THAT MOISTURE GETS PULLED UP OUT OF THE GULF
OF MEXICO AS THE NEW MEXICO UPPER LOW LIFTS NORTHEAST. IN
ADDITION...THERE IS WEAK LIFT ON THESE SURFACES...WHICH GIVEN THAT
THE TEMPERATURE PROFILE HAS NO ICE...COULD LEAD TO FREEZING DRIZZLE
FORMATION. AS SUCH...HAVE RETAINED A MENTION OF FREEZING DRIZZLE
FROM 21-00Z...BUT RESTRICTED IT TO THE SOUTHEAST 1/3 OF THE AREA TO
CORRELATE WITH THE LIFT ON THE 275-280K SURFACES. ELSEWHERE...DRY
CONDITIONS WILL PREVAIL WITH PERHAPS LITTLE IN THE WAY OF CLOUD
COVER UNTIL LATER SATURDAY. WITH CLEAR SKIES AND DRY AIR TONIGHT...
ALONG WITH LIGHT WINDS IN MOST LOCATIONS EXCEPT FOR SOUTHEAST
MINNESOTA...TEMPERATURES COULD REALLY TANK TONIGHT. WENT SLIGHTLY
BELOW GUIDANCE FOR THE TYPICAL COLD SPOTS AS THINK THEY SHOULD BE
ABLE TO COME CLOSE TO ZERO. SINGLE DIGITS LOOK LIKELY ELSEWHERE.
925MB TEMPS ARE FAIRLY SIMILAR TO TODAY FOR SATURDAY...AND WITH
PLENTY OF SUN...HIGHS SHOULD TOP OUT CLOSE TO THOSE TODAY.
SATURDAY NIGHT AND SUNDAY...MODELS SHOW ANOTHER SHORTWAVE COMING OUT
OF SOUTH CENTRAL CANADA LATE SATURDAY...DROPPING SOUTHEAST INTO
WESTERN ILLINOIS BY 18Z SUNDAY. THIS SHORTWAVE WILL HELP TO KICK THE
TROUGH DROPPING INTO NEBRASKA EASTWARD...BUT ALSO BRING WITH IT A
SURGE OF DRY...COLDER AIR. BY 18Z SUNDAY...925MB TEMPS OVER THE
FORECAST AREA ARE AROUND -8C. PRIOR TO THE COLD AIR ARRIVAL...THERE
IS A CONCERN TO DEAL WITH WHICH IS THE SAME AS SATURDAY...LOW
STRATUS AND ANY LIGHT PRECIPITATION POSSIBLE WITH IT. IN THIS
CASE...MODELS HAVE AN AREA OF STRATUS COMING INTO THE FORECAST AREA
BEHIND A COLD FRONT ASSOCIATED WITH THE NEBRASKA TROUGH. VERY LITTLE
IF ANY ISENTROPIC LIFT IS NOTED WITHIN THIS STRATUS...SO THINK ANY
LIGHT PRECIPITATION POTENTIAL WOULD REMAIN OVER THE SOUTHEAST THIRD
OF THE AREA EARLY IN THE EVENING AHEAD OF THE FRONT. AGAIN...THIS IS
LIKELY TO BE FREEZING DRIZZLE GIVEN LACK OF ICE IN THE CLOUD. AFTER
MIDNIGHT...THERE ARE INDICATIONS OF A SECONDARY TROUGH WHICH IN
925MB TEMPS ALMOST LOOKS LIKE A WARM FRONT DROPPING SOUTH THROUGH
WISCONSIN. 270-275K ISENTROPIC LIFT PLOTS SHOW SOME LOW LEVEL LIFT
WITH THIS...LIKELY ENOUGH TO PRODUCE LIGHT PRECIPITATION. IT APPEARS
ICE WILL EXIST IN THE CLOUD THIS TIME...AIDED TOO BY MID CLOUDS
DROPPING SOUTH WITH THE SHORTWAVE COMING OUT OF SOUTH CENTRAL
CANADA. THUS...HAVE MAINTAINED A FLURRY MENTION. DRYING AND CLEARING
WILL TAKE PLACE SUNDAY MORNING FROM NORTHWEST TO SOUTHEAST. THE
INCREASE OF CLOUDS AND COLD ADVECTION WILL COUNTER-ACT EACH OTHER
SATURDAY NIGHT FOR LOWS...AND HAVE WENT WITH A BLEND OF GUIDANCE
SUGGESTING TEMPERATURES DROPPING INTO THE TEENS. SLIGHTLY COLDER DAY
EXPECTED ON SUNDAY GIVEN THE AFOREMENTIONED 925MB TEMPS.
SUNDAY NIGHT AND MONDAY...ATTENTION TURNS TO DEEP TROUGHING JUST OFF
THE WEST COAST OF NORTH AMERICA. OTHER THAN THE 04.12Z NAM...ALL
OTHER MODELS DEPICT THE TROUGH PROGRESSING EASTWARD INTO THE WESTERN
U.S. THROUGH THE WEEKEND AND SPLITTING INTO TWO. THE SOUTHERN
PART FORMS INTO A CUT-OFF LOW WHICH GETS STUCK IN THE SOUTHWESTERN
U.S.. THE NORTHERN PART IS A TROUGH THAT TRACKS ALONG THE
U.S./CANADIAN BORDER...BRINGING WITH IT A DYING COLD FRONT INTO
WESTERN MINNESOTA ON MONDAY. REGARDING THAT 04.12Z NAM...THE MODEL
HAS BEEN DISCOUNTED AS AN OUTLIER AS IT KEEPS A FULL SCALE TROUGH
AND MARCHES IT EASTWARD INTO THE PLAINS BY 00Z TUESDAY. NO MATTER
WHAT MODEL SOLUTION IS FOLLOWED...THIS PERIOD ENDS UP DRY WITH WARM
ADVECTION THROUGHOUT AS LOW LEVEL SOUTHWEST WINDS INCREASE AHEAD OF
THE APPROACHING SPLIT TROUGH AND DYING SURFACE COLD FRONT. 925MB
TEMPS CLIMB TO -2 TO -4C BY 18Z MONDAY WHILE 850MB TEMPS JUMP TO +2
TO +4C. THUS...MONDAY SHOULD END UP MUCH WARMER THAN SUNDAY WITH
MOST LOCATIONS TOPPING OUT FROM THE UPPER 20S TO MID 30S PER ECMWF
GUIDANCE. COLDEST LOCATIONS EXPECTED OVER SOUTHEAST MINNESOTA AND
NORTHEAST IOWA WITH HIGHER ALBEDO FROM SNOWPACK. LOWS SUNDAY NIGHT
LIKELY IN THE EVENING BEFORE SOUTHWEST WINDS PICK UP. FOLLOWED BLEND
OF GUIDANCE FOR LOWS.
.LONG TERM...MONDAY NIGHT THROUGH FRIDAY
233 PM CST FRI JAN 4 2013
FOCUS AS HAS BEEN THE PAST FEW DAYS IS ON THE UPPER LOW IN THE
SOUTHWESTERN U.S. ON MONDAY. YET AGAIN THERE IS A SPLIT IN SCENARIOS
AMONGST MODEL HANDLING OF THIS UPPER LOW:
1. THE 04.12Z CANADIAN REPRESENTS A VERY FAST SCENARIO...LIFTING IT
NORTHEAST ACROSS CHICAGO TUESDAY NIGHT. WE WOULD END UP WITH A LIGHT
TO MODERATE SNOWFALL ACROSS THE FORECAST AREA TUESDAY INTO TUESDAY
NIGHT SHOULD THIS VERIFY.
2. NEXT BEHIND THE CANADIAN IS THE 04.12Z GFS...LIFTING IT FROM
TEXAS ON TUESDAY INTO THE OHIO VALLEY ON WEDNESDAY. THIS SCENARIO
WOULD IT PAN OUT WOULD KEEP THE AREA DRY AND TEMPERATURES ABOVE
NORMAL THROUGH THURSDAY.
3. LASTLY...THE 04.12Z ECMWF/UKMET ARE EXTREMELY CONSISTENT WITH
PAST ECMWF RUNS...HAVING THE UPPER LOW CROSS NORTHERN MEXICO ON
TUESDAY...SHIFTING INTO TEXAS ON WEDNESDAY...THEN LIFTING INTO
ILLINOIS ON THURSDAY. THIS SCENARIO WOULD YIELD ABOVE NORMAL
TEMPERATURES THROUGH THURSDAY...WITH DRY WEATHER THROUGH WEDNESDAY
EVENING...RAIN TO MUCH OF THE AREA FOR LATE WEDNESDAY NIGHT INTO
THURSDAY...THEN TAPERING OFF TO A SNOW OR RAIN/SNOW MIX THURSDAY
NIGHT.
THE WHOLE PROBLEM RESULTING IN THE VARIOUS SCENARIOS STARTS ON
SUNDAY...REGARDING HOW QUICK THE DEEP UPPER TROUGH SPLITS INTO TWO
AND HOW FAST UPPER RIDGING CAN BUILD INTO THE PACIFIC NORTHWEST
BEHIND IT. PER HPC AND WANTING TO FOLLOW THE CONSISTENT AND GOOD
EXTENDED VERIFYING ECMWF...LEANED THE LONG TERM FORECAST MORE
TOWARDS THE ECMWF SOLUTION. THIS ALSO IS IN BETTER AGREEMENT WITH
THE PREVIOUS FORECAST. STILL HAVE ENDED UP KEEPING A SNOW OR
RAIN/SNOW MIX IN FOR WEDNESDAY NIGHT INTO THURSDAY MORNING...TO
HANDLE UNCERTAINTY ON THE TEMPERATURE RISE AND NOT WANTING TO
INTRODUCE FREEZING RAIN SINCE THAT TYPE SEEMS UNLIKELY.
AFTER THURSDAY...NEW DEEP TROUGHING IS FORECAST TO FORM BY ALL
MODELS OVER THE WESTERN U.S....WHICH IS ONE OF THE FEATURES THAT
HELPS KICK OUT THE UPPER LOW IN THE ECMWF/UKMET. SHORTWAVES EJECTING
OUT OF THE TROUGH REQUIRE CHANCES OF SNOW IN FOR FRIDAY. COOLER
TEMPERATURES ARE LIKELY AS WELL...THOUGH AT LEAST FOR FRIDAY STILL
CLOSE TO NORMAL AS THE DEEPER COLDER AIR ASSOCIATED WITH THE TROUGH
HOLDS OFF UNTIL THE WEEKEND.
&&
.AVIATION...THROUGH 06Z SUNDAY
1141 PM CST FRI JAN 4 2013
CLEAR SKIES AND LIGHT WINDS WILL CONTINUE TO RULE INTO THE MORNING
HOURS WITH SOME HAZE/MIST POSSIBLE AT RST IF WINDS CAN REMAIN
LIGHT AT LESS THAN 5KTS. FORECAST SOUNDINGS SHOW A FAIRLY STEEP
LOW LEVEL INVERSION WITH ANY MOISTURE BEING LOCKED IN AT THE VERY
LOWEST LEVEL. SO ANY HZ/BR THAT DOES FORM WILL BE VERY SHALLOW AND
IS NOT EXPECTED TO DROP BELOW MVFR. THAT SAID...SOME OBS HAVE
QUICKLY DROPPED DOWN TO A MILE ACROSS PORTIONS OF NORTHERN
MINNESOTA AND WISCONSIN WHERE WINDS ARE MUCH LIGHTER.
THE FOCUS THEN GOES TO LATE SATURDAY AFTERNOON AND EVENING AS LOW
LEVEL MOISTURE IS ON THE INCREASE AHEAD OF A PAIR OF SYSTEMS
MOVING INTO THE REGION. DESPITE THE DEEPER LOW LEVEL MOISTURE
APPEARING TO STAY TO THE SOUTHEAST...FORECAST SOUNDINGS SHOW THAT
THERE SHOULD BE ENOUGH MOISTURE POOLING UNDER A SHALLOW INVERSION
IN THE EVENING FOR LOW LEVEL CLOUDS TO FORM. GIVEN THAT THIS HAS
BEEN A CONSISTENT SIGNAL FOR A FEW DAYS NOW...DECIDED TO GO AHEAD
AND PUT THIS INTO THE TAFS.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
233 PM CST FRI JAN 4 2013
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...AJ
LONG TERM...AJ
AVIATION...HALBACH
AREA FORECAST DISCUSSION
NWS TAUNTON MA
1005 AM EST SAT JAN 5 2013
.SYNOPSIS...
MAINLY DRY AND SEASONABLY COLD WEATHER WILL CONTINUE THROUGH
TODAY. THERE IS A CHANCE OF A FEW SNOW SHOWERS/FLURRIES LATE
TONIGHT INTO SUNDAY...AND AGAIN SUNDAY NIGHT INTO MONDAY.
TEMPERATURES WILL WARM TO ABOVE NORMAL LEVEL THE MIDDLE AND END
OF NEXT WEEK. DRY WEATHER SHOULD PREVAIL MUCH OF NEXT WEEK.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
10 AM UPDATE...
ONLY MINOR ADJUSTMENTS NECESSARY FOR THIS MID MORNING UPDATE.
LATEST MAV/RAP TEMPS/DEWPOINTS ARE LOOKING GOOD SO HAVE ADJUSTED
TOWARD THOSE VALUES FOR THE REMAINDER OF THE DAY.
OTHERWISE...STILL A BIT OF A LAKE CONNECTION WITH SOME LOW LVL
STRATO-CU IN THE W INTERIOR AND N OF ROUTE 2. IT MAY TAKE UNTIL
ABOUT MID AFTERNOON...ONCE A MORE NLY COMPONENT TO THE WIND SETS
IN FOR THIS CONNECTION TO CUTOFF. LIKED THE NAMDNG5 AND RAP WHICH
BOTH SHOWED THIS POTENTIAL SO HAVE ADJUSTED TOWARD THOSE SOLUTIONS
FOR SKIES. OTHERWISE MUCH OF THE FORECAST REMAINS ON TRACK.
PREVIOUS DISCUSSION...
MID LEVEL SHORTWAVE CONTINUING TO MAKE PROGRESS ACROSS NORTHERN
NEW ENGLAND EARLY THIS MORNING. WEST WINDS STARTING TO INCREASE AS
THIS PACKET OF ENERGY GET CLOSER. THESE WEST WINDS ARE STRONG
ENOUGH TO SUPPLY GREAT LAKES MOISTURE EAST OF THE BERKSHIRES.
EXPECTING THESE CLOUDS TO DECREASE THROUGH THE MORNING IN THE WAKE
OF THE DEPARTING SHORTWAVE. GUIDANCE IS DOING THIS TOO QUICKLY
THOUGH. SLOWED DOWN THE CLEARING BASED ON OBSERVED IR SATELLITE
DATA. EVEN SO...LOCATIONS NEAR THE BERKSHIRES AND ACROSS SOUTHERN
NH MAY HOLD ONTO CLOUDS LONGER THAN CURRENT FORECAST WHERE THE
GREAT LAKES MOISTURES A CONCERN.
TEMPERATURES WERE A BLEND OF THE MOS GUIDANCE.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM SUNDAY/...
ANOTHER MID-LEVEL SHORTWAVE APPROACHES FROM THE WEST. EXPECTING
INCREASING CLOUDS LATE THIS EVENING AND AFTER MIDNIGHT. THE FAIR
SKIES AND LIGHT WINDS SHOULD ALLOW FOR GOOD RADIATIONAL COOLING
DURING THE FIRST PART OF THE NIGHT. AS SUCH EXPECTING MINIMUM
TEMPERATURES BELOW FREEZING ACROSS ALL OF SOUTHERN NEW ENGLAND BY
THE TIME ANY PRECIPITATION ARRIVES.
THERE IS DECENT ISENTROPIC LIFT...BUT DEEP MOISTURE WILL CONTINUE
TO BE AN ISSUE. MOST OF THE 05/00Z GUIDANCE DEPICTS A SCENARIO
WHERE THERE IS A SMALL WINDOW OF OPPORTUNITY WHERE THERE ARE
ACTIVE ICE NUCLEI ACROSS THE REGION. THIS TIMING DOES NOT QUITE
MATCH UP WITH A MOIST BOUNDARY LAYER...SO MOST OF THE SNOW WHICH
IS GENERATED ALOFT WILL LIKELY SUBLIMATE INTO THE DRY AIR NEAR THE
SURFACE. EVENTUALLY THE COLUMN WILL BE SUFFICIENTLY MOIST FOR SOME
OF THE SNOW TO REACH THE GROUND. AT THAT POINT THOUGH THERE LIKELY
WILL NOT BE ENOUGH TIME TO ACCUMULATE MUCH.
MAINTAINED THE IDEA OF JUST A CHANCE OF MEASURABLE WATER
EQUIVALENT ACROSS SOUTHERN NEW ENGLAND FOR NOW. WILL NEED TO
KEEP AN EYE ON THE MOVING PARTS IN CASE THEY LINE UP BETTER LATE
TONIGHT INTO SUNDAY MORNING. EXPECTING MAINLY DRY WEATHER FOR THE
AFTERNOON AS THE TIMING OF A LOW PRESSURE IN THE SOUTHERN JET
STREAM LOOKS SLOWER.
TEMPERATURES WERE A BLEND OF THE MOS GUIDANCE.
&&
.LONG TERM /SUNDAY NIGHT THROUGH FRIDAY/...
HIGHLIGHTS...
* COLD TEMPS MON FOLLOWED BY WARMING TEMPS THRU THE WEEK
* RAIN POSSIBLE TOWARDS THE END OF THE WEEK
MODELS ARE IN GOOD AGREEMENT THROUGH THE TUESDAY. THEN DIFFERENCES
START TO APPEAR BETWEEN THE ECMWF AND THE GFS. GENERALLY A QUIET
PATTERN FOR SOUTHERN NEW ENGLAND THROUGH MID WEEK. COOLER
TEMPERATURES MONDAY WILL BE FOLLOWED BY A FAIRLY SIGNIFICANT WARM UP
THROUGH THE REST OF THE WEEK. MODELS DIFFER ON THE PATTERN FOR THE
END OF THE WEEK. THE GFS BRINGS LOW PRESSURE THROUGH QUEBEC WITH A
COLD FRONT THROUGH SOUTHERN NEW ENGLAND WEDNESDAY WHILE THE ECMWF
KEEPS HIGH PRESSURE AND DRY WEATHER. THEN ESSENTIALLY THE OPPOSITE
ON THURSDAY. FRIDAY...THEY AGREE ON ANOTHER LOW PRESSURE SYSTEM
MOVING THROUGH QUEBEC...WITH THE ECMWF BRINGING A COLD FRONT AND
PRECIP INTO SOUTHERN NEW ENGLAND AND THE GFS KEEPING THINGS DRY.
THE GFS ENSEMBLES LOOK PRETTY EVENLY SPLIT BETWEEN SOMETHING THAT
LOOKS LIKE THE OPERATIONAL GFS AND SOMETHING THAT LOOKS MORE LIKE
THE ECMWF. ALL THIS TO SAY CONFIDENCE IS LOW FOR THE LATER PART OF
THE WEEK.
SUNDAY NIGHT AND MONDAY...LOW PRESSURE MOVES THROUGH NORTHERN NEW
ENGLAND SUNDAY NIGHT...BRINGING A COLD FRONT ACROSS SOUTHERN NEW
ENGLAND. THIS FRONTAL PASSAGE LOOKS PRETTY STARVED FOR MOISTURE AT
THIS POINT. CAN/T RULE OUT A FEW FLURRIES...PARTICULARLY ACROSS THE
NORTHWESTERN ZONES...BUT EXPECT IT TO BE FAIRLY DRY. THIS WILL
BRING ONE MORE ROUND OF COLDER TEMPERATURES TO THE REGION MONDAY AS
HIGH PRESSURE BUILDS INTO THE AREA. AT TIMES MONDAY WHEN THE WIND
DIRECTION IS OFF THE OCEAN...MAY SEE A PERIOD OF OCEAN EFFECT SNOW
ALONG THE EAST COAST. WILL KEEP CHANCE POPS IN FOR THIS
POSSIBILITY.
TUESDAY...QUIET WEATHER EXPECTED WITH THE START OF A WARMING TREND
THAT WILL LAST THROUGHOUT THE WEEK.
WEDNESDAY THROUGH FRIDAY...AS STATED ABOVE THIS PERIOD HAS A LOT OF
UNCERTAINTY IN IT REGARDING THE POTENTIAL FOR RAIN. TEMPERATURE
PROFILES ARE FAIRLY SIMILAR ACROSS THE MODELS...WITH THE WARMING
TREND CONTINUING OR LEVELING OFF THROUGH THE END OF THE WEEK. WILL
INTRODUCE SLIGHT CHANCE POPS FOR WEDNESDAY AND THURSDAY TO ACCOUNT
FOR THE DIFFERENCES IN THE MODELS. KEEPING CHANCE POPS FOR FRIDAY
WHEN BOTH MODELS INDICATE SOME RAIN. NO PTYPE PROBLEMS HERE...TEMPERATURES
SHOULD BE WARM ENOUGH FOR RAIN ACROSS THE AREA. A BLEND OF MODEL
GUIDANCE SHOULD WORK WELL FOR TEMPERATURES.
&&
.AVIATION /15Z SATURDAY THROUGH WEDNESDAY/...
SHORT TERM...HIGH CONFIDENCE.
MAINLY VFR THROUGH TODAY. MVFR CIGS LIKELY TOWARD THE HIGHER
TERRAIN OF THE BERKSHIRES. GUSTY W-SW WINDS BECOMING NORTHWEST
AND DIMINISHING LATER TODAY. MVFR CONDITIONS POSSIBLE IN SCATTERED
SNOW SHOWERS LATE TONIGHT INTO SUNDAY. MOSTLY VFR BY SUNDAY
AFTERNOON.
KBOS TAF...HIGH CONFIDENCE IN TAF.
KBDL TAF...HIGH CONFIDENCE IN TAF.
OUTLOOK...SUNDAY NIGHT THROUGH WEDNESDAY...
HIGH CONFIDENCE. MAINLY VFR CONDITIONS EXPECTED. LOW PROBABILITY
OF OCEAN EFFECT SNOW SHOWERS LOWERING CONDITIONS TO MVFR BRIEFLY
MONDAY.
&&
.MARINE...
HIGH CONFIDENCE IN AN IMPROVING TREND ACROSS THE COASTAL WATERS.
REPLACED GALE WARNINGS WITH SMALL CRAFT ADVISORIES BASED ON
LATEST BUOY OBSERVATIONS. STILL A LOW PROBABILITY FOR A GUST TO 35
KT ACROSS THE OUTER COASTAL WATERS EAST OF MASSACHUSETTS THIS
MORNING.
HIGH PRESSURE BUILDS OVER THE WATERS LATER TODAY. THIS WILL BRING
DIMINISHING WIND...BECOMING LIGHT THIS EVENING AND MUCH OF
TONIGHT. WINDS SHOULD INCREASE AGAIN LATE SUNDAY AS ANOTHER LOW
PRESSURE APPROACHES THE WATERS.
OUTLOOK...SUNDAY THROUGH WEDNESDAY...
MODERATE TO HIGH CONFIDENCE THROUGH WEDNESDAY.
SEAS WILL BE 5 TO 6 FEET ON THE OUTER WATERS THROUGH MUCH OF THE
PERIOD. WINDS WILL GUST TO SMALL CRAFT CRITERIA LATE SUNDAY NIGHT
INTO MONDAY MORNING AND AGAIN ON TUESDAY. OTHERWISE...WINDS REMAIN
BELOW SMALL CRAFT CRITERIA. SNOW SHOWERS ARE POSSIBLE MONDAY...
PARTICULARLY ON THE EASTERN WATERS.
&&
.BOX WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
MA...NONE.
NH...NONE.
RI...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 5 PM EST THIS AFTERNOON FOR
ANZ231>235-237-251-256.
SMALL CRAFT ADVISORY UNTIL 8 PM EST THIS EVENING FOR ANZ250-
254-255.
&&
$$
SYNOPSIS...BELK/RLG
NEAR TERM...BELK/DOODY
SHORT TERM...BELK
LONG TERM...RLG
AVIATION...BELK/RLG
MARINE...BELK/RLG
AREA FORECAST DISCUSSION
NWS GOODLAND KS
439 AM MST SAT JAN 5 2013
.SHORT TERM...(TODAY THROUGH SUNDAY)
ISSUED AT 236 AM MST SAT JAN 5 2013
04Z WATER VAPOR IMAGERY AND RAP ANALYSIS INDICATED UPPER LEVEL LOW
CIRCULATION CENTERED OVER THE OKLAHOMA PANHANDLE MOVING
NORTHEAST...WITH A SECOND SHORT WAVE TROUGH DIVING TO THE SOUTHEAST
ACROSS THE NORTHERN PLAINS. FOR THE MOST PART...00Z SOUNDINGS HAD
WARMED AND DRIED FROM 24 HOURS AGO WITH THE ONLY EXCEPTION BEING
H75-H5 MOISTENING AT DDC IN ADVANCE OF SOUTHERN LOW. MOISTENING WAS
LIMITED TO THIS LEVEL HOWEVER...WITH LARGE SUB CLOUD DRY LATER
NOTED.
TODAY-SUNDAY...TROUGH TO THE SOUTH WILL GRADUALLY LIFT TO THE
NORTHEAST THIS MORNING AS NEXT SYSTEM APPROACHES FROM THE NORTH.
WHILE THERE IS A BIT OF ASCENT EXPECTED...SYSTEMS FOR THE MOST PART
DO NOT BRING ANY MEANINGFUL INFLUX OF MOISTURE TO THE AREA. WITH
OBSERVED SOUNDINGS AROUND THE AREA INDICATING VERY DRY
CONDITIONS...ESPECIALLY BELOW H7...LEADS ME TO THINK DEPARTING
SYSTEM WILL LEAD TO MUCH MORE THAN A PERIOD OF MID CLOUDS...ALTHOUGH
WILL MONITOR. SYSTEM APPROACHING FROM THE NORTH WILL HAVE SIMILAR
MOISTURE AVAILABILITY ISSUES DURING THE AFTERNOON AS IT MOVES ACROSS
THE AREA. MAIN CONCERN WITH THIS SECOND SYSTEM WILL BE THE SHARP
INCREASE IN WIND SPEEDS OFF OF THE SURFACE...ESPECIALLY AS
SUBSIDENCE INCREASES IN THE AFTERNOON. HAVE BUMPED UP THE WINDS INTO
THE 15 TO 25 MPH CATEGORY FOR THE TIME BEING...AS THE LINGERING
IMPACT OF SNOW COVER MAKES CONFIDENCE IN DEEP MIXING TOO LOW TO
BRING DOWN HIGHER SPEEDS. STRONG SUBSIDENCE WILL OVERSPREAD THE AREA
TONIGHT AS SHORT WAVE RIDGE MOVES OVER THE AREA. THIS WILL LEAD TO
CONTINUED DRY AND MOSTLY CLEAR CONDITIONS THROUGH SUNDAY MORNING
BEFORE CLOUDS BEGIN TO INCREASE LATE IN THE AFTERNOON AS RIDGE
SHIFTS TO THE EAST OF THE AREA. OVERALL CURRENT FORECAST LOOKS
REASONABLE CONSIDERING LATEST SUITE OF DATA AND ONLY MADE A FEW
MINOR CHANGES TO TEMPS.
.LONG TERM...(SUNDAY NIGHT THROUGH FRIDAY)
ISSUED AT 236 AM MST SAT JAN 5 2013
SUNDAY NIGHT-MONDAY NIGHT...H5 TROUGH WILL SPLIT INTO A NORTHERN AND
SOUTHERN SYSTEM OVER THE WESTERN CONUS WITH GOOD MODEL AGREEMENT
THAT SOUTHERN TROUGH WILL DIVE TO THE SOUTH ALONG THE US/MEXICO
BORDER AND REMAINING WELL TO THE SOUTH OF THE AREA WHILE NORTHERN
TROUGH MOVES ACROSS THE NORTHERN PLAINS. WITH THE EXPECTED TRACK OF
THE UPPER LEVEL SYSTEMS...EXPECT DRY CONDITIONS TO CONTINUE ACROSS
THE AREA WITH NO MEANINGFUL THREAT FOR PRECIPITATION. THESE SYSTEMS
WILL STILL HAVE A SMALL IMPACT ON THE AREA AS SFC TROUGH DEEPENS ON
SUNDAY RESULTING IN SOUTHERLY WINDS INCREASING TO 15 TO 25MPH LATE
SUNDAY AFTERNOON AND REMAIN GUSTY OVERNIGHT. EXPECTING THIS TO HOLD
UP MIN TEMPERATURES SEVERAL DEGREES WITH A FEW AREAS REMAINING ABOVE
NORMAL FOR LOWS.
TUESDAY THROUGH FRIDAY...MODELS HAVE COME INTO BETTER AGREEMENT
WITH THE DEVELOPMENT/TRACK OF THE UPPER LEVEL LOW OVER THE DESERT
SOUTHWEST ON TUESDAY. MODELS HAVE THE CLOSED LOW MOVING OVER
OKLAHOMA AND NORTHERN TEXAS WEDNESDAY NIGHT. AS THE LOW MOVES
NORTH ISENTROPIC LIFT WILL DEVELOP OVER THE SOUTHEAST PART OF THE
AREA...LEADING TO SOME CHANCES FOR PRECIPITATION. AS THE CLOSED
LOW MOVES NORTHEAST THURSDAY PRECIPITATION WILL COME TO AN END.
THURSDAY ANOTHER UPPER LEVEL TROUGH WILL MOVE OVER THE
INTER-MOUNTAIN WEST TOWARD THE AREA. AHEAD OF THE UPPER LEVEL
TROUGH A COLD FRONT WILL MOVE INTO THE AREA LATE THURSDAY NIGHT.
PRECIPITATION CHANCES INCREASE BEHIND THE FRONT AS
ISENTROPIC/SYNOPTIC LIFT AND MOISTURE INCREASE. AT THIS TIME WILL
KEEP PRECIPITATION CHANCES AND MOISTURE AMOUNTS ON THE LOW END DUE TO
FAIRLY WEAK LIFT AHEAD OF THE TROUGH.
TEMPERATURES FOR THE PERIOD WILL BE NEAR NORMAL THROUGH THURSDAY.
BELOW NORMAL TEMPERATURES RETURN BEHIND THE COLD FRONT THURSDAY
NIGHT.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SUNDAY MORNING)
ISSUED AT 436 AM MST SAT JAN 5 2013
VFR CONDITIONS WILL PREVAIL FOR THE NEXT 24 HOURS WITH WESTERLY
WINDS SHIFTING TO THE NORTH AND INCREASING TO 13 TO 20KTS THIS
AFTERNOON BEFORE DECREASING AFTER SUNSET.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
CO...NONE.
NE...NONE.
&&
$$
SHORT TERM...JRM
LONG TERM...JRM/JTL
AVIATION...JRM
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
655 AM EST SAT JAN 5 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 527 AM EST SAT JAN 5 2013
WV LOOP AND 00Z RAOBS INDICATE WNW FLOW ALOFT ON PERIPHERY OF POLAR
VORTEX CENTERED OVER NUNAVUT CANADA ACROSS HUDSON BAY. COLD AIR IS
NEAR BY WITH H85 TEMPS BLO -15C OVER NORTHERN ONTARIO AND SFC TEMPS
BLO ZERO. FAIRLY MILD BY COMPARISON ACROSS UPR LAKES THOUGH AS H85
TEMPS ARE AROUND -1C. SHALLOW COLD AIR HAS ALLOWED SPOTS ALONG WI
BORDER THAT HAVE CLEAR SKIES TO DROP INTO SINGLE DIGITS ABOVE ZERO.
WARMER AIR AT H85 IS SEEN UPSTREAM OVER NORTHERN PLAINS WITH ABR AT
+4C AND MPX AT +2C. MAIN SHORTWAVE UPSTREAM IS CROSSING ALBERTA AND
SASKATCHEWAN THIS MORNING IN THE NORTHERN STREAM. ALSO IS A WAVE OVER
THE SOUTHERN PLAINS IN THE SOUTHERN STREAM. NORTHERN STREAM WAVE IS
WELL AGREED UPON BY MODELS TO SLIDE INTO NORTHERN PLAINS TODAY AND
DIG ACROSS UPPER LAKES LATE TONIGHT INTO SUNDAY MORNING AS H4-H3 JET
STREAK IN POLAR JET STREAM DIGS INTO WEST SIDE OF TROUGH. ASSOCIATED
SFC LOW IS JUST GETTING GOING OVER WESTERN NORTH DAKOTA WITH MSLP OF
1015MB. OUT AHEAD OF THE LOW TODAY...CURIOUS ON HOW WARM TEMPS WILL
GET. RAP HANDLES LOW CLOUDS WELL RIGHT NOW AND IT INDICATES PARTIAL
CLEARING OF CLOUDS OVER WEST THIS MORNING INTO EARLY AFTN...WHILE
CLOUDS HANG IN OVER KEWEEENAW AND ALSO DOWNWIND OF SW FLOW OVER LK
MICHIGAN. MIXING TO 950MB-925MB SUPPORTS HIGHS REACHING INTO THE 30S
AGAIN FOR MOST AREAS. ONLY PRECIP TODAY WOULD BE OVER EAST WHERE SOME
DRIZZLE MAY OCCUR WITH ADDITIONAL MOISTURE PROVIDED BY LK MICHIGAN.
AS TROUGH DEEPENS TONIGHT...SO TO DOES SFC LOW AS IT MOVES ACROSS LK
SUPERIOR/UPR MICHIGAN. BASED ON 1000-900MB THICKNESS
PACKING...EXPECT COLD FRONT TO DROP OVER NORTHWEST PORTION OF CWA
03Z-06Z TONIGHT AND REACH THE FAR EASTERN CWA BTWN 09Z-12Z.
SOUNDINGS FM NAM AND GFS GENERALLY SIMILAR SHOWING LOW-LEVEL
MOISTURE BUILDING UP AOA 800MB AS TROUGH DEEPENS ACROSS AREA.
MARGINALLY COLD INITIALLY EVEN AFTER FROPA WITH MOISTURE BARELY
REACHING -10C ISOTHERM. KEPT MENTION OF DRIZZLE AND/OR FREEZING
DRIZZLE THROUGH EVENING THEN AS TROUGH DEEPENS/MOISTURE DEPTH
INCREASES AND COLD AIR ADVECTION DEVELOPS /H85 TEMPS FALLING TO
AROUND -11C BY 12Z SUNDAY/ EXPECT A PERIOD OF LAKE ENHANCED SNOW
SHOWERS TO FORM. NORTH WINDS IN MOIST LAYER AND AXIS OF H85 THERMAL
TROUGH POINT TO FAR WEST AND NORTH CENTRAL CWA TO SEE MOST SNOW
TONIGHT. SINCE COLD AIR LAGS FARTHER TO THE EAST...KEPT MENTION OF
FREEZING DRIZZLE IN AT ISQ-ERY UNTIL AROUND 09Z.
USED BLEND OF HIGHER RESOLUTION GUIDANCE TO COME UP WITH QPF/SNOW
AMOUNTS FOR TONIGHT. IN GENERAL MOST OF THESE GUIDANCE SETS CAME UP
WITH AN AVERAGE OF 0.20 INCH FOR 6 HR QPF OVER HIGHER TERRAIN OF
WEST AND NORTH CENTRAL. ALSO LEANED ON LOCAL LK EFFECT GUIDANCE TO
MAKE SURE MODEL DERVIED OUTPUT WAS NOT TOO FAR OUT OF LINE. AT THE
MOST WOULD EXPECT 2-3 INCHES OF SNOW TONIGHT FOR FAVORED AREAS NEAR
LK SUPERIOR AND MAINLY LESS THAN 1 INCH OVER REST OF NORTHERN CWA.
DUE TO STRONGER NORTH WINDS IN BLYR...SNOW PROBABLY FALLS OVER SOUTH
CWA AS WELL...BUT ANY ACCUMS WILL BE MINOR. DO EXPECT TO SEE SNOW
ACCUMS REACH OVER MUCH OF GOGEBIC COUNTY...INTO FAR SOUTHERN
PORTIONS OF MARQUETTE COUNTY AND ALSO OVER NORTHERN PORTION OF DELTA
COUNTY DUE TO THOSE STRONGER WINDS. AS TROUGH DEEPENS AND DEEPER
MOISTURE EXPANDS BRIEFLY MAY SEE SNOW BECOME MORE WIDESPREAD...AT
LEAST BRIEFLY...OVER ROUGHLY EAST THIRD OF CWA WELL AFTER 06Z. THIS
COULD BOOST SNOW AMOUNTS EVEN IN NON-TRADITIONAL LK EFFECT AREAS OF
ALGER/SCHOOLCRAFT/LUCE COUNTIES.
WINDS WILL SHIFT ABRUBTLY TO THE NORTH BEHIND THE COLD FRONT. GUSTS
ALONG LK SUPERIOR FROM KEWEENAW PENINSULA TOWARD BIG BAY/MARQUETTE
AND EVENTUALLY MUNISING MAY REACH OVER 30 MPH LATE TONIGHT.
.LONG TERM...(SUNDAY THROUGH FRIDAY)
ISSUED AT 527 AM EST SAT JAN 5 2013
AS ADVERTISED IN LATE DEC...EARLY JAN HAS STARTED ON THE QUIET SIDE
WITH REGARD TO PCPN IN THE UPPER LAKES. IT LOOKS LIKE THAT WILL
CONTINUE THRU THE FIRST HALF OF THE COMING WEEK. AS IN LATE DEC...
SPLIT FLOW PERSISTS...THOUGH THE SRN STREAM IS LESS ACTIVE AND THE
NRN STREAM IS MORE ACTIVE. IN THE NRN STREAM...A TROF CURRENTLY
DOMINATES ERN CANADA DOWNSTREAM OF RIDGING OVER WRN CANADA THAT
EXTENDS N INTO THE ARCTIC. THIS PLACES THE UPPER LAKES UNDER WNW
FLOW. OVER THE NEXT SEVERAL DAYS...THE RIDGE/TROF OVER WRN/ERN
CANADA RESPECTIVELY WILL RELAX WITH POLAR VORTEX SETTLING INTO A
POSITION NW OF HUDSON BAY. THIS WILL BRING A TRANSITION TO ZONAL
FLOW ACROSS SRN CANADA...ALLOWING MILD PACIFIC AIR TO WASH ACROSS
THE CONUS. THUS...TEMPS HERE DURING THE UPCOMING WEEK WILL BE WELL
ABOVE NORMAL FOR JAN. HEADING INTO THE LATTER PORTION OF THE WEEK...
MEDIUM RANGE GUIDANCE HAS BEEN CONSISTENTLY SUGGESTING TROF
AMPLIFICATION OVER THE WRN CONUS AS RIDGE BEGINS TO BUILD THRU THE
NE PACIFIC TOWARD AK. THIS WILL LIKELY BREAK THE RECENT DRY
PATTERN...PERHAPS AS EARLY AS MIDWEEK AS SRN STREAM ENERGY MAY BE
FORCED FAR ENOUGH N TO BRING A SHIELD OF PCPN (QUITE POSSIBLY MOSTLY
RAIN) INTO UPPER MI. FARTHER DOWN THE ROAD...THERE HAVE BEEN AND
CONTINUE TO BE HINTS FROM MEDIUM RANGE GUIDANCE THAT AT LEAST A
PORTION OF MID TO LATE JAN COULD TURN COLD AS WRN TROF SLOWLY SHIFTS
E INTO CNTRL NAMERICA. HOWEVER...THE FORECASTED MJO PHASE FAVORS
WARM WEATHER OVER THE ERN HALF OF THE CONUS DURING THAT PERIOD.
THUS...IT WILL BE INTERESTING TO SEE HOW FAR E THE TROF SHIFTS AND
HOW FAR SE AND E ARCTIC AIR MOVES. IN ANY EVENT...ASSUMING TROF DOES
MAKE SOME EASTWARD PROGRESS...POTENTIAL SHOULD BE THERE FOR AN
ACTIVE WINTER STORM TRACK FOR A TIME FROM THE SRN ROCKIES/SRN PLAINS
E AND NE INTO AREAS FROM THE MISSISSIPPI RIVER VALLEY EASTWARD.
SO...FOR THOSE LOOKING FOR SNOW FOR OUTDOOR ACTIVITIES...THERE MAY
BE A FAVORABLE WINDOW OF OPPORTUNITY DURING THE MIDDLE OF JAN IF
TROF AND COLDER AIR DON`T END UP BEING HELD TO THE W.
AS ALLUDED TO ABOVE...WARM AND MOSTLY DRY WEATHER WILL BE THE RULE
HEADING INTO THE MIDDLE OF THE COMING WEEK. CLIPPER NRN STREAM
SHORTWAVE THAT DIVES INTO THE WRN LAKES TONIGHT WILL BE QUICKLY
EXITING THE AREA SUN. SOLID HEIGHT RISES AND A CRUSHING INVERSION
DOWN TO 3KFT SUGGEST LIGHT LES OCCURRING SUN MORNING WILL END W TO E
DURING THE DAY...ENDING FIRST OVER THE W. THERE WILL BE AN
OPPORTUNITY FOR TEMPS TO PLUMMET SUN EVENING AS SFC RIDGE AND PERIOD
OF LIGHT/CALM WINDS SHIFTS QUICKLY ACROSS THE AREA. MID/HIGH SINGLE
DIGITS SHOULD GENERALLY BE THE RULE IN THE INTERIOR WITH TEMPS
SHOWING SOME RISE OVERNIGHT IN MANY LOCATIONS. LARGE TEMP BUST
POTENTIAL IS PRESENT AS THERE MAY BE ENOUGH TIME FOR TRADITIONAL
COLD SPOTS TO SLIP BLO ZERO.
GIVEN THE NOTABLY BETTER RUN-TO-RUN CONTINUITY OF THE ECMWF OVER THE
LAST SEVERAL RUNS AND GFS TRENDS TOWARD THE ECMWF...WILL LEAN
STRONGLY TOWARD THE ECMWF FOR MUCH OF THE FCST DURING THE COMING
WEEK. ANY PCPN THRU MIDWEEK WILL DEPEND ON HOW CLOSE ANY SHORTWAVES
PASS TO THE AREA IN THE ZONAL FLOW. AT THIS POINT...WITH ZONALLY
ORIENTED JET SHIFTING N OF THE AREA...PCPN CHANCES APPEAR MINIMAL
THRU MIDWEEK AS EASTWARD TRACKING SHORTWAVES SHOULD PASS N OF THE
AREA.
ON MON...TRANSITION TO ZONAL FLOW ACROSS SRN CANADA WILL BE FULLY
UNDERWAY...AND A SHORTWAVE WILL BE MOVING FROM MANITOBA IN THE
MORNING TO NRN ONTARIO IN THE AFTN. WITH LACK OF MOISTURE UNDER
ZONAL FLOW AND TRACK OF WAVE WELL TO THE N...PCPN IS NOT EXPECTED
HERE. IT SHOULD BE BREEZY/WINDY MON AS 55-65KT LOW-LEVEL JET
TRANSLATES ACROSS THE AREA. FORTUNATELY...STABILITY WILL LIMIT
MIXING DEPTH...BUT FAVORABLE TRACK OF PRES FALL MAX ACROSS NRN
ONTARIO JUST N OF LAKE SUPERIOR COULD MAKE FOR A WIND ADVY EVENT FOR
SOME LOCATIONS. SOUTHERLY WINDS FAVOR ERN ALGER/SCHOOLCRAFT/LUCE FOR
STRONGEST WINDS WITH KERY AND GRAND MARAIS ESPECIALLY FAVORED.
ELSEWHERE...DOWNSLOPE WARMING ALONG LAKE SUPERIOR MAY ENCOURAGE
DEEPER MIXING/STRONGER MOMENTUM TRANSPORT IN THOSE LOCATIONS AS
WELL. SOLID GALES EXPECTED ON LAKE SUPERIOR (GUSTS AT HIGH OBS
PLATFORMS MAY REACH STORM FORCE). GALES ALSO EXPECTED ON NRN LAKE
MI. UNDER BREEZY S/SW WINDS...HIGHS WILL TOP OUT IN THE 30S ACROSS
THE AREA AND COULD NEAR 40F IN LOCATIONS THAT SEE DOWNSLOPING.
WARMTH CONTINUES TUE AS NEXT SHORTWAVE TRACKS ACROSS CNTRL
SASKATCHEWAN TOWARD FAR NRN ONTARIO. IT WILL BE ANOTHER DAY OF WELL
ABOVE NORMAL TEMPS FOR JAN. WHILE MID/HIGH CLOUDS SHOULD KEEP
WARMING IN CHECK...STILL EXPECT HIGHS AGAIN INTO THE 30S.
ANOTHER SHORTWAVE WILL TAKE A TRACK A LITTLE FARTHER S ON WED. WHILE
THAT COULD IMPROVE THE CHC OF A LITTLE PCPN...IT`S NOT WORTHY OF A
MENTION AT THIS POINT GIVEN THE ZONAL PATTERN. WED SHOULD BE ANOTHER
DAY WITH 30S THE RULE FOR HIGH TEMPS.
THE END OF THE WEEK TURNS MORE INTERESTING. AS FLOW BUCKLES WITH WRN
TROF TAKING SHAPE THU/FRI...ATTENTION TURNS TO THE CLOSED SRN STREAM
LOW THAT WILL BE OVER SRN CA SUN AND IN THE VCNTY OF W TX WED.
ALTHOUGH WITH SOME TIMING VARIATION...THE ECMWF HAS BEEN VERY
CONSISTENT SHOWING THIS SYSTEM GETTING KICKED NE THRU THE MID
MISSISSIPPI VALLEY AND INTO THE GREAT LAKES REGION IN RESPONSE TO
THE DEEPENING WRN TROF. LOOKS LIKE PCPN...QUITE POSSIBLY ALL RAIN...
WILL SPREAD INTO UPPER MI THU. COLUMN MAY COOL JUST ENOUGH THU NIGHT
FOR PCPN TO CHANGE TO PREDOMINANTLY SNOW OVER HIGHER TERRAIN. THERE
IS STILL SUFFICIENT UNCERTAINTY IN HOW THIS SRN STREAM SYSTEM WILL
TRACK TO KEEP POPS ONLY IN THE CHC CATEGORY.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SUNDAY MORNING)
ISSUED AT 652 AM EST SAT JAN 5 2013
BKN MVFR CIGS GIVE WAY TO A PERIOD OF MAINLY CLEAR SKIES AFTER MID
MORNING AT CMX AND SAW. SKIES ARE ALREADY CLEAR AT IWD. EXPECT
APPROACHING LOW PRESSURE SYSTEM AND A COLD FRONT TO RESULT IN LOWER
CLOUDS AGAIN LATE TODAY THROUGH TONIGHT. CIGS INITIALLY MVFR BUT
SHOULD TREND IFR THROUGH THE EVENING. EXPECT LGT FREEZING DRIZZLE OR
SNOW THROUGH EVENING...CHANGING TO SNOW SHOWERS OVERNIGHT TONIGHT.
ONLY INCLUDED FZDZ AT IWD THIS EVENING DUE TO MORE FAVORABLE NORTH
WINDS/UPSLOPE. IFR CONDITIONS SHOULD THEN PREVAIL AT IWD AND SAW
OVERNIGHT TONIGHT AS NORTH WINDS CONTINUE. AT CMX...SINCE LOCAL
CLIMATOLOGY SUGGESTS NORTH WINDS ARE NOT AS FAVORABLE FOR PERSISTENT
LOWER CIGS/VSBY...KEPT CONDITIONS MVFR. NORTH WINDS OFF LK SUPERIOR
COULD BE GUSTY LATE TONIGHT...ESPECIALY AT SAW WHERE GUSTS MAY EXCEED
25 KTS THROUGH DAYBREAK ON SUNDAY. IMPROVING CONDITIONS DEVELOP ON
SUNDAY AT ALL THE TAF SITES WITH DIMINISHING SNOW SHOWERS AND CIGS
MAINLY MVFR TO LOWER VFR.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 527 AM EST SAT JAN 5 2013
LOW PRESSURE SHIFTING ACROSS THE UPPER GREAT LAKES WILL RESULT IN A
COLD FRONT MOVING ACROSS LAKE SUPERIOR THIS EVENING OVER WESTERN
LAKE SUPERIOR AND BY LATE IN THE NIGHT OVER THE FAR EASTERN PORTION
OF THE LAKE. EXPECT LIGHT EAST-SOUTHEAST WINDS LESS THAN 20 KTS
AHEAD OF THE FRONT TO RAPIDLY INCREASE TO 20-30 KTS FROM THE NORTH
IN THE WAKE OF THE FRONT. GALE FORCE GUSTS ARE NOT OUT OF THE
QUESTION OVER CNTRL LK SUPERIOR AFTER MIDNIGHT DUE TO SHARP PRESSURE
RISES BUILDING IN BRIEFLY BEHIND THE LOW PRESSURE/COLD FRONT.
RIDGE OF HIGH PRES QUICKLY PASSES ACROSS THE UPPER LAKES SUN
EVENING...BRINGING A BRIEF PERIOD OF LIGHT WINDS. THEN...NEXT LOW
PRES SYSTEM TRACKING E INTO NRN ONTARIO MON WILL BRING A SUBSTANTIAL
AND RAPID INCREASE IN S TO SW WINDS ACROSS LAKE SUPERIOR LATE SUN
NIGHT/MON. ALTHOUGH STABILITY OF TEMP PROFILE WILL LIMIT MIXING TO
VERY STRONG WINDS OF 55-65KT AS LOW AS 2-3KFT ABOVE THE LAKE SFC...
FAVORABLE TRACK OF PRES FALL MAX JUST N OF LAKE SUPERIOR WILL BE AN
ENHANCING FACTOR. AT THIS POINT...SOLID MID RANGE GALES ARE EXPECTED
ACROSS THE LAKE MON. HIGH OBS PLATFORMS WILL PROBABLY SEE GUSTS
REACH STORM FORCE. GALES WILL END MON NIGHT AS LOW CONTINUES
EASTWARD AND WINDS VEER SW TO W. BY TUE AFTN...WINDS WILL BE UNDER
20KT.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...JLA
LONG TERM...ROLFSON
AVIATION...JLA
MARINE...JLA/ROLFSON
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
529 AM EST SAT JAN 5 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 527 AM EST SAT JAN 5 2013
WV LOOP AND 00Z RAOBS INDICATE WNW FLOW ALOFT ON PERIPHERY OF POLAR
VORTEX CENTERED OVER NUNAVUT CANADA ACROSS HUDSON BAY. COLD AIR IS
NEAR BY WITH H85 TEMPS BLO -15C OVER NORTHERN ONTARIO AND SFC TEMPS
BLO ZERO. FAIRLY MILD BY COMPARISON ACROSS UPR LAKES THOUGH AS H85
TEMPS ARE AROUND -1C. SHALLOW COLD AIR HAS ALLOWED SPOTS ALONG WI
BORDER THAT HAVE CLEAR SKIES TO DROP INTO SINGLE DIGITS ABOVE ZERO.
WARMER AIR AT H85 IS SEEN UPSTREAM OVER NORTHERN PLAINS WITH ABR AT
+4C AND MPX AT +2C. MAIN SHORTWAVE UPSTREAM IS CROSSING ALBERTA AND
SASKATCHEWAN THIS MORNING IN THE NORTHERN STREAM. ALSO IS A WAVE OVER
THE SOUTHERN PLAINS IN THE SOUTHERN STREAM. NORTHERN STREAM WAVE IS
WELL AGREED UPON BY MODELS TO SLIDE INTO NORTHERN PLAINS TODAY AND
DIG ACROSS UPPER LAKES LATE TONIGHT INTO SUNDAY MORNING AS H4-H3 JET
STREAK IN POLAR JET STREAM DIGS INTO WEST SIDE OF TROUGH. ASSOCIATED
SFC LOW IS JUST GETTING GOING OVER WESTERN NORTH DAKOTA WITH MSLP OF
1015MB. OUT AHEAD OF THE LOW TODAY...CURIOUS ON HOW WARM TEMPS WILL
GET. RAP HANDLES LOW CLOUDS WELL RIGHT NOW AND IT INDICATES PARTIAL
CLEARING OF CLOUDS OVER WEST THIS MORNING INTO EARLY AFTN...WHILE
CLOUDS HANG IN OVER KEWEEENAW AND ALSO DOWNWIND OF SW FLOW OVER LK
MICHIGAN. MIXING TO 950MB-925MB SUPPORTS HIGHS REACHING INTO THE 30S
AGAIN FOR MOST AREAS. ONLY PRECIP TODAY WOULD BE OVER EAST WHERE SOME
DRIZZLE MAY OCCUR WITH ADDITIONAL MOISTURE PROVIDED BY LK MICHIGAN.
AS TROUGH DEEPENS TONIGHT...SO TO DOES SFC LOW AS IT MOVES ACROSS LK
SUPERIOR/UPR MICHIGAN. BASED ON 1000-900MB THICKNESS
PACKING...EXPECT COLD FRONT TO DROP OVER NORTHWEST PORTION OF CWA
03Z-06Z TONIGHT AND REACH THE FAR EASTERN CWA BTWN 09Z-12Z.
SOUNDINGS FM NAM AND GFS GENERALLY SIMILAR SHOWING LOW-LEVEL
MOISTURE BUILDING UP AOA 800MB AS TROUGH DEEPENS ACROSS AREA.
MARGINALLY COLD INITIALLY EVEN AFTER FROPA WITH MOISTURE BARELY
REACHING -10C ISOTHERM. KEPT MENTION OF DRIZZLE AND/OR FREEZING
DRIZZLE THROUGH EVENING THEN AS TROUGH DEEPENS/MOISTURE DEPTH
INCREASES AND COLD AIR ADVECTION DEVELOPS /H85 TEMPS FALLING TO
AROUND -11C BY 12Z SUNDAY/ EXPECT A PERIOD OF LAKE ENHANCED SNOW
SHOWERS TO FORM. NORTH WINDS IN MOIST LAYER AND AXIS OF H85 THERMAL
TROUGH POINT TO FAR WEST AND NORTH CENTRAL CWA TO SEE MOST SNOW
TONIGHT. SINCE COLD AIR LAGS FARTHER TO THE EAST...KEPT MENTION OF
FREEZING DRIZZLE IN AT ISQ-ERY UNTIL AROUND 09Z.
USED BLEND OF HIGHER RESOLUTION GUIDANCE TO COME UP WITH QPF/SNOW
AMOUNTS FOR TONIGHT. IN GENERAL MOST OF THESE GUIDANCE SETS CAME UP
WITH AN AVERAGE OF 0.20 INCH FOR 6 HR QPF OVER HIGHER TERRAIN OF
WEST AND NORTH CENTRAL. ALSO LEANED ON LOCAL LK EFFECT GUIDANCE TO
MAKE SURE MODEL DERVIED OUTPUT WAS NOT TOO FAR OUT OF LINE. AT THE
MOST WOULD EXPECT 2-3 INCHES OF SNOW TONIGHT FOR FAVORED AREAS NEAR
LK SUPERIOR AND MAINLY LESS THAN 1 INCH OVER REST OF NORTHERN CWA.
DUE TO STRONGER NORTH WINDS IN BLYR...SNOW PROBABLY FALLS OVER SOUTH
CWA AS WELL...BUT ANY ACCUMS WILL BE MINOR. DO EXPECT TO SEE SNOW
ACCUMS REACH OVER MUCH OF GOGEBIC COUNTY...INTO FAR SOUTHERN
PORTIONS OF MARQUETTE COUNTY AND ALSO OVER NORTHERN PORTION OF DELTA
COUNTY DUE TO THOSE STRONGER WINDS. AS TROUGH DEEPENS AND DEEPER
MOISTURE EXPANDS BRIEFLY MAY SEE SNOW BECOME MORE WIDESPREAD...AT
LEAST BRIEFLY...OVER ROUGHLY EAST THIRD OF CWA WELL AFTER 06Z. THIS
COULD BOOST SNOW AMOUNTS EVEN IN NON-TRADITIONAL LK EFFECT AREAS OF
ALGER/SCHOOLCRAFT/LUCE COUNTIES.
WINDS WILL SHIFT ABRUBTLY TO THE NORTH BEHIND THE COLD FRONT. GUSTS
ALONG LK SUPERIOR FROM KEWEENAW PENINSULA TOWARD BIG BAY/MARQUETTE
AND EVENTUALLY MUNISING MAY REACH OVER 30 MPH LATE TONIGHT.
.LONG TERM...(SUNDAY THROUGH FRIDAY)
ISSUED AT 527 AM EST SAT JAN 5 2013
AS ADVERTISED IN LATE DEC...EARLY JAN HAS STARTED ON THE QUIET SIDE
WITH REGARD TO PCPN IN THE UPPER LAKES. IT LOOKS LIKE THAT WILL
CONTINUE THRU THE FIRST HALF OF THE COMING WEEK. AS IN LATE DEC...
SPLIT FLOW PERSISTS...THOUGH THE SRN STREAM IS LESS ACTIVE AND THE
NRN STREAM IS MORE ACTIVE. IN THE NRN STREAM...A TROF CURRENTLY
DOMINATES ERN CANADA DOWNSTREAM OF RIDGING OVER WRN CANADA THAT
EXTENDS N INTO THE ARCTIC. THIS PLACES THE UPPER LAKES UNDER WNW
FLOW. OVER THE NEXT SEVERAL DAYS...THE RIDGE/TROF OVER WRN/ERN
CANADA RESPECTIVELY WILL RELAX WITH POLAR VORTEX SETTLING INTO A
POSITION NW OF HUDSON BAY. THIS WILL BRING A TRANSITION TO ZONAL
FLOW ACROSS SRN CANADA...ALLOWING MILD PACIFIC AIR TO WASH ACROSS
THE CONUS. THUS...TEMPS HERE DURING THE UPCOMING WEEK WILL BE WELL
ABOVE NORMAL FOR JAN. HEADING INTO THE LATTER PORTION OF THE WEEK...
MEDIUM RANGE GUIDANCE HAS BEEN CONSISTENTLY SUGGESTING TROF
AMPLIFICATION OVER THE WRN CONUS AS RIDGE BEGINS TO BUILD THRU THE
NE PACIFIC TOWARD AK. THIS WILL LIKELY BREAK THE RECENT DRY
PATTERN...PERHAPS AS EARLY AS MIDWEEK AS SRN STREAM ENERGY MAY BE
FORCED FAR ENOUGH N TO BRING A SHIELD OF PCPN (QUITE POSSIBLY MOSTLY
RAIN) INTO UPPER MI. FARTHER DOWN THE ROAD...THERE HAVE BEEN AND
CONTINUE TO BE HINTS FROM MEDIUM RANGE GUIDANCE THAT AT LEAST A
PORTION OF MID TO LATE JAN COULD TURN COLD AS WRN TROF SLOWLY SHIFTS
E INTO CNTRL NAMERICA. HOWEVER...THE FORECASTED MJO PHASE FAVORS
WARM WEATHER OVER THE ERN HALF OF THE CONUS DURING THAT PERIOD.
THUS...IT WILL BE INTERESTING TO SEE HOW FAR E THE TROF SHIFTS AND
HOW FAR SE AND E ARCTIC AIR MOVES. IN ANY EVENT...ASSUMING TROF DOES
MAKE SOME EASTWARD PROGRESS...POTENTIAL SHOULD BE THERE FOR AN
ACTIVE WINTER STORM TRACK FOR A TIME FROM THE SRN ROCKIES/SRN PLAINS
E AND NE INTO AREAS FROM THE MISSISSIPPI RIVER VALLEY EASTWARD.
SO...FOR THOSE LOOKING FOR SNOW FOR OUTDOOR ACTIVITIES...THERE MAY
BE A FAVORABLE WINDOW OF OPPORTUNITY DURING THE MIDDLE OF JAN IF
TROF AND COLDER AIR DON`T END UP BEING HELD TO THE W.
AS ALLUDED TO ABOVE...WARM AND MOSTLY DRY WEATHER WILL BE THE RULE
HEADING INTO THE MIDDLE OF THE COMING WEEK. CLIPPER NRN STREAM
SHORTWAVE THAT DIVES INTO THE WRN LAKES TONIGHT WILL BE QUICKLY
EXITING THE AREA SUN. SOLID HEIGHT RISES AND A CRUSHING INVERSION
DOWN TO 3KFT SUGGEST LIGHT LES OCCURRING SUN MORNING WILL END W TO E
DURING THE DAY...ENDING FIRST OVER THE W. THERE WILL BE AN
OPPORTUNITY FOR TEMPS TO PLUMMET SUN EVENING AS SFC RIDGE AND PERIOD
OF LIGHT/CALM WINDS SHIFTS QUICKLY ACROSS THE AREA. MID/HIGH SINGLE
DIGITS SHOULD GENERALLY BE THE RULE IN THE INTERIOR WITH TEMPS
SHOWING SOME RISE OVERNIGHT IN MANY LOCATIONS. LARGE TEMP BUST
POTENTIAL IS PRESENT AS THERE MAY BE ENOUGH TIME FOR TRADITIONAL
COLD SPOTS TO SLIP BLO ZERO.
GIVEN THE NOTABLY BETTER RUN-TO-RUN CONTINUITY OF THE ECMWF OVER THE
LAST SEVERAL RUNS AND GFS TRENDS TOWARD THE ECMWF...WILL LEAN
STRONGLY TOWARD THE ECMWF FOR MUCH OF THE FCST DURING THE COMING
WEEK. ANY PCPN THRU MIDWEEK WILL DEPEND ON HOW CLOSE ANY SHORTWAVES
PASS TO THE AREA IN THE ZONAL FLOW. AT THIS POINT...WITH ZONALLY
ORIENTED JET SHIFTING N OF THE AREA...PCPN CHANCES APPEAR MINIMAL
THRU MIDWEEK AS EASTWARD TRACKING SHORTWAVES SHOULD PASS N OF THE
AREA.
ON MON...TRANSITION TO ZONAL FLOW ACROSS SRN CANADA WILL BE FULLY
UNDERWAY...AND A SHORTWAVE WILL BE MOVING FROM MANITOBA IN THE
MORNING TO NRN ONTARIO IN THE AFTN. WITH LACK OF MOISTURE UNDER
ZONAL FLOW AND TRACK OF WAVE WELL TO THE N...PCPN IS NOT EXPECTED
HERE. IT SHOULD BE BREEZY/WINDY MON AS 55-65KT LOW-LEVEL JET
TRANSLATES ACROSS THE AREA. FORTUNATELY...STABILITY WILL LIMIT
MIXING DEPTH...BUT FAVORABLE TRACK OF PRES FALL MAX ACROSS NRN
ONTARIO JUST N OF LAKE SUPERIOR COULD MAKE FOR A WIND ADVY EVENT FOR
SOME LOCATIONS. SOUTHERLY WINDS FAVOR ERN ALGER/SCHOOLCRAFT/LUCE FOR
STRONGEST WINDS WITH KERY AND GRAND MARAIS ESPECIALLY FAVORED.
ELSEWHERE...DOWNSLOPE WARMING ALONG LAKE SUPERIOR MAY ENCOURAGE
DEEPER MIXING/STRONGER MOMENTUM TRANSPORT IN THOSE LOCATIONS AS
WELL. SOLID GALES EXPECTED ON LAKE SUPERIOR (GUSTS AT HIGH OBS
PLATFORMS MAY REACH STORM FORCE). GALES ALSO EXPECTED ON NRN LAKE
MI. UNDER BREEZY S/SW WINDS...HIGHS WILL TOP OUT IN THE 30S ACROSS
THE AREA AND COULD NEAR 40F IN LOCATIONS THAT SEE DOWNSLOPING.
WARMTH CONTINUES TUE AS NEXT SHORTWAVE TRACKS ACROSS CNTRL
SASKATCHEWAN TOWARD FAR NRN ONTARIO. IT WILL BE ANOTHER DAY OF WELL
ABOVE NORMAL TEMPS FOR JAN. WHILE MID/HIGH CLOUDS SHOULD KEEP
WARMING IN CHECK...STILL EXPECT HIGHS AGAIN INTO THE 30S.
ANOTHER SHORTWAVE WILL TAKE A TRACK A LITTLE FARTHER S ON WED. WHILE
THAT COULD IMPROVE THE CHC OF A LITTLE PCPN...IT`S NOT WORTHY OF A
MENTION AT THIS POINT GIVEN THE ZONAL PATTERN. WED SHOULD BE ANOTHER
DAY WITH 30S THE RULE FOR HIGH TEMPS.
THE END OF THE WEEK TURNS MORE INTERESTING. AS FLOW BUCKLES WITH WRN
TROF TAKING SHAPE THU/FRI...ATTENTION TURNS TO THE CLOSED SRN STREAM
LOW THAT WILL BE OVER SRN CA SUN AND IN THE VCNTY OF W TX WED.
ALTHOUGH WITH SOME TIMING VARIATION...THE ECMWF HAS BEEN VERY
CONSISTENT SHOWING THIS SYSTEM GETTING KICKED NE THRU THE MID
MISSISSIPPI VALLEY AND INTO THE GREAT LAKES REGION IN RESPONSE TO
THE DEEPENING WRN TROF. LOOKS LIKE PCPN...QUITE POSSIBLY ALL RAIN...
WILL SPREAD INTO UPPER MI THU. COLUMN MAY COOL JUST ENOUGH THU NIGHT
FOR PCPN TO CHANGE TO PREDOMINANTLY SNOW OVER HIGHER TERRAIN. THERE
IS STILL SUFFICIENT UNCERTAINTY IN HOW THIS SRN STREAM SYSTEM WILL
TRACK TO KEEP POPS ONLY IN THE CHC CATEGORY.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SATURDAY NIGHT)
ISSUED AT 1249 AM EST SAT JAN 5 2013
LOW LEVEL MOISTURE ACROSS THE AREA BELOW AN INVERSION AROUND 3K FT
IS EXPECTED TO PERSIST OVERNIGHT BUT GRADUALLY DISSIPATE FROM THE
WSW LATE. MVFR CIGS AT IWD AND SAW ARE EXPECTED TO GIVE WAY TO VFR
CONDITIONS BY AROUND 09Z TO 12Z. HOWEVER...MODELS SUGGEST THAT THE
MOISTURE BAND WILL LINGER AT CMX. A SHORTWAVE AND SFC TROUGH MOVING
INTO THE REGION SATURDAY SHOULD BRING IN MVFR CIGS THAT MAY DROP
INTO THE IFR RANGE SAT EVENING. SOME LIGHT SNOW OR POSSIBLY FREEZING
DRIZZLE MAY ALSO BE POSSIBLE.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 527 AM EST SAT JAN 5 2013
LOW PRESSURE SHIFTING ACROSS THE UPPER GREAT LAKES WILL RESULT IN A
COLD FRONT MOVING ACROSS LAKE SUPERIOR THIS EVENING OVER WESTERN
LAKE SUPERIOR AND BY LATE IN THE NIGHT OVER THE FAR EASTERN PORTION
OF THE LAKE. EXPECT LIGHT EAST-SOUTHEAST WINDS LESS THAN 20 KTS
AHEAD OF THE FRONT TO RAPIDLY INCREASE TO 20-30 KTS FROM THE NORTH
IN THE WAKE OF THE FRONT. GALE FORCE GUSTS ARE NOT OUT OF THE
QUESTION OVER CNTRL LK SUPERIOR AFTER MIDNIGHT DUE TO SHARP PRESSURE
RISES BUILDING IN BRIEFLY BEHIND THE LOW PRESSURE/COLD FRONT.
RIDGE OF HIGH PRES QUICKLY PASSES ACROSS THE UPPER LAKES SUN
EVENING...BRINGING A BRIEF PERIOD OF LIGHT WINDS. THEN...NEXT LOW
PRES SYSTEM TRACKING E INTO NRN ONTARIO MON WILL BRING A SUBSTANTIAL
AND RAPID INCREASE IN S TO SW WINDS ACROSS LAKE SUPERIOR LATE SUN
NIGHT/MON. ALTHOUGH STABILITY OF TEMP PROFILE WILL LIMIT MIXING TO
VERY STRONG WINDS OF 55-65KT AS LOW AS 2-3KFT ABOVE THE LAKE SFC...
FAVORABLE TRACK OF PRES FALL MAX JUST N OF LAKE SUPERIOR WILL BE AN
ENHANCING FACTOR. AT THIS POINT...SOLID MID RANGE GALES ARE EXPECTED
ACROSS THE LAKE MON. HIGH OBS PLATFORMS WILL PROBABLY SEE GUSTS
REACH STORM FORCE. GALES WILL END MON NIGHT AS LOW CONTINUES
EASTWARD AND WINDS VEER SW TO W. BY TUE AFTN...WINDS WILL BE UNDER
20KT.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...JLA
LONG TERM...ROLFSON
AVIATION...JLB
MARINE...JLA/ROLFSON
AREA FORECAST DISCUSSION
NWS DULUTH MN
535 AM CST SAT JAN 5 2013
.AVIATION...12Z TAFS.
VFR WITH PATCHY MVFR CIGS OVER THE MN ARROWHEAD AND ISOLD LIFR
CIGS/VSBYS IN FZFG AT THE OUTSET. EXPECT MORE CLOUDS TO FORM AS
SFC LOW MOVES INTO MN LATER TODAY. MVFR CIGS ARE ANTICIPATED WITH
SOME -SN OR FLURRIES DEVELOPING AROUND 18Z AS AN UPPER LEVEL TROF
ARRIVES. AFTER 01Z...LOOK FOR AN IMPROVEMENT TO VFR AS THE SFC LOW
DEPARTS AND HIGH PRESSURE MOVES IN.
&&
.PREV DISCUSSION... /ISSUED 301 AM CST SAT JAN 5 2013/
SHORT TERM...TODAY THROUGH SUNDAY.
A WEAK SURFACE LOW PRESSURE SYSTEM OVER NORTH DAKOTA WILL SLIDE
EASTWARD OVER NORTHERN MINNESOTA AND NORTHERN WISCONSIN TODAY. THIS
WILL BRING A SLIGHT CHANCE OF LIGHT SNOW THIS AFTERNOON AND EVENING
TO THE NORTHLAND. LITTLE IF ANY SNOW ACCUMULATIONS WILL OCCUR WITH
THIS SYSTEM. THE ONLY EXCEPTION WILL BE THE BAYFIELD PENINSULA AND
GOGEBIC RANGE WHERE LAKE EFFECT SNOWS WILL BEGIN ONCE THE LOW MOVES
TO THE EAST OVER THE EASTERN GREAT LAKES LATE SATURDAY NIGHT. THE
LAKE EFFECT SNOW SHOWERS WILL BEGIN TO TAPER OFF SUNDAY AS HIGH
PRESSURE BUILDS IN FROM THE CENTRAL PLAINS. SNOW ACCUMULATIONS FOR
THE BAYFIELD PENINSULA AND GOGEBIC RANGE WILL BE ONE TO TWO INCHES
WITH MOST OF THAT FALLING BETWEEN 06Z AND 12Z ON SUNDAY. HIGH
TEMPERATURES WILL AVERAGE SLIGHTLY ABOVE NORMAL OVER THE
WEEKEND...MAINLY IN THE LOWER TO MID 20`S.
LONG TERM...SUNDAY NIGHT THROUGH FRIDAY.
A STRONG AREA OF LOW PRESSURE WILL MOVE THROUGH SOUTH CENTRAL CANADA
JUST N OF THE INTERNATIONAL BORDER SUNDAY NIGHT THROUGH MONDAY
NIGHT. DUE TO THE TRACK OF THIS LOW...DO NOT EXPECT ANY SNOW OVER
THE NORTHERN TIER OF THE FA NEXT TO CANADA. WITH THE TIGHTENING
PRESSURE GRADIENT...THE WIND SPEED WILL INCREASE AND BE QUITE BRISK
ON MONDAY. THE WIND SHOULD DIMINISH MONDAY NIGHT HOWEVER AS THE
CANADIAN SFC LOW MOVES QUICKLY TO THE E. HIGH PRESSURE COVERS THE
AREA ON TUESDAY. BY TUESDAY NIGHT...THE MODELS DIVERGE WITH THE NEXT
AREA OF LOW PRESSURE. GFS TAKES THE LOW RIGHT THROUGH THE FA...ECMWF
IS WAY UP IN CANADA...THE GEM BARELY HAS A LOW CENTER SLOWLY MOVING
THROUGH MANITOBA. USED A BLENDED APPROACH WITH SMALL CHANCE POPS
TUESDAY NIGHT AND WEDNESDAY. THE MODELS GROW FARTHER APART WITH TIME
FOR THE REMAINDER OF THE LONG TERM AND USED A BLENDED APPROACH FOR
POPS/WEATHER.
AVIATION...06Z TAFS
MOST OF THE MVFR CEILINGS OVER FAR NORTHEAST MINNESOTA HAVE
DIMINISHED THIS EVENING...WITH MORE OVER FAR NORTH CENTRAL
WISCONSIN/UPPER MICHIGAN. SOME FOG AND IFR CEILINGS HAVE DEVELOPED
AS WELL...AND WE DID ADD VSBY REDUCTIONS AND IFR CEILINGS IN SOME
OF THE TAFS...PARTICULARLY KHIB. WE HAVE YET TO SEE MUCH LOWER
CLOUD DEVELOPMENT LATE THIS EVENING OUTSIDE OF THE SPOTTY IFR
CONDITIONS...AND THE RAP SEEMS TO BE HANDLING CLOUDS BETTER THAN
THE HRRR. AS LOW LEVEL WAA STRENGTHENS OVERNIGHT...WE STILL MAY
SEE SOME DEVELOPMENT LATE EXPANDING INTO SATURDAY. THE LOW IS
STILL FORECAST TO TRACK ACROSS CENTRAL-NORTHERN MINNESOTA
SATURDAY INTO UPPER MICHIGAN BY 00Z SUN. WE KEPT THE TAFS DRY
UNTIL 00Z...THEN IT APPEARS ENOUGH SATURATION WILL OCCUR TO GET
SOME LIGHT SNOW/FLURRIES. MORE SUBSTANTIAL SNOW SHOWERS WILL OCCUR
ALONG THE SOUTH SHORE DUE TO NORTHERLY WINDS FLOWING OVER THE
LAKE.
&&
.POINT TEMPS/POPS...
DLH 23 9 22 11 / 20 20 0 0
INL 20 -1 18 12 / 10 10 0 0
BRD 20 3 20 11 / 20 10 0 0
HYR 24 12 24 11 / 20 30 10 0
ASX 27 17 26 15 / 20 30 10 0
&&
.DLH WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
LS...NONE.
&&
$$
AVIATION...GSF
AREA FORECAST DISCUSSION
NWS JACKSON MS
1000 AM CST SAT JAN 5 2013
.UPDATE...
LATEST SATELLITE IMAGERY SHOWED AN UPPER DISTURBANCE MOVING NORTHEAST OVER
NORTHWEST MISSOURI LATE THIS MORNING. IT WAS BRINGING IN ISENTROPIC
LIFT ON TOP OF A 1030 MB SURFACE RIDGE IN THE FORM OF VERY LIGHT
RAIN. MORNING SOUNDINGS SHOWS SOME LOW LEVEL DRY AIR WHICH WAS
MOISTENING UP FROM TOP DOWN. LATEST LOCAL WRF AND AND RUC SHOWS LIGHT
RAIN ACROSS THE REGION WITH THE BEST COVERAGE ACROSS THE SOUTHEAST
2/3RDS BEFORE ENDING FROM THE NORTHWEST THIS EVENING. CURRENT HIGHS
IN THE UPPER 40S TO MIDDLE 50S LOOKS TO BE ON TRACK. HAVE LOWERED
POPS SOME TO MOSTLY LIKELY CATEGORY FOR TODAY BEFORE LOWERING TO
CHANCE CATEGORY BY MID AFTERNOON./17/
./PREVIOUS DISCUSSION...400 AM CST SAT JAN 5 2013
.SHORT TERM...(TODAY THROUGH SUNDAY NIGHT)...
DECENT MID LEVEL DISTURBANCE IN THE OK PANHANDLE MOVING ENE AT 30KTS
THIS MORNING AND DRAGGING MOISTURE OVER THE TOP OF OUR SURFACE RIDGE
AXIS(1030MB) CENTERED ALONG THE MS RIVER NEAR KGLH. ISENTROPIC
UPGLIDE ON THE 300-310K SURFACES WILL BE ENOUGH FOR WIDESPREAD
SPRINKLES STARTING BY DAYLIGHT WRN HALF AND SPREADING OVER THE ENTIRE
CWFA BEFORE MIDDAY. CANNOT TOTALLY RULE OUT A FEW REPORTS OF SLEET AT
THE ONSET OF THE RAIN BUT THE NARROW LOW LEVEL DRY LAYER WAS ERODING
AT A RAPID PACE.
OVERALL...BEST MOISTURE TRANSPORT AND OMEGA APPEARS TO CROSS SRN 1/3
OF THE AREA SO WILL HAVE BEST CATEGORICAL POPS FOR MEASURING ONE
QUARTER INCH RAINFALL AMOUNTS. OTHERWISE...MOST LOCATIONS REMAIN
UNDER A TENTH OF AN INCH AS CLOUDY SKIES AND VERY MINIMAL WINDS SEE
TEMPS HOLDING MAINLY M-U40S.
THE LIGHT RAINS END RATHER QUICKLY FROM W TO E THIS EVENING BUT
CLOUDS MAY LINGER UNTIL A WEAK LOW LEVEL TROUGH PASSES EARLY SUNDAY
MORNING. EARLY SUNDAY LOWS SHOULD HOLD IN THE M-U30S. SKIES SHOULD
CLEAR SUNDAY MORNING WITH INCREASING DOWNGLIDE AND DRYING AIRMASS
COMING IN FROM THE CENTRAL ROCKIES. EVEN WITH EXPECTED SUNSHINE
SUNDAY AFTERNOON...HIGHS STAY IN THE NEAR NORMAL 50S. THAT LEADS
INTO A CLEAR AND CHILLY SUNDAY NIGHT WITH ANOTHER SURFACE HIGH OF
1032MB POSITIONED IN SRN MO MOVING E. A GOOD RADIATIONAL COOLING
SETUP FOR US EARLY MONDAY SHOULD BRING MORE FROST AND LOW TEMPS
AGAIN IN THE U20-L30S. /40/
.LONG TERM...(MONDAY THROUGH SATURDAY)...
NEAR NORMAL CONDITIONS WILL OPEN THE WORK WEEK AS HIGHS MON CLIMB
INTO THE MID 50S. A FEW MID AND HIGH LEVEL CLOUDS WILL BE STREAMING
BY AS A WEAK/MOISTURE STARVED S/WV LIFTS ACROSS THE REGION IN
SOUTHWESTERLY FLOW ALOFT. STRONG HIGH PRESSURE WILL TAKE ANCHOR
ALONG THE EASTERN SEABOARD ON TUE ALLOWING A WARMING TREND TO
COMMENCE HEADED INTO THE MIDDLE PORTION OF THE WEEK...ALONG WITH
INCREASING CLOUD COVER AS TIME PASSES.
THE MAIN FOCUS FOR THIS FORECAST PACKAGE IS ON THE EVOLUTION OF A
CLOSED LOW THE MODELS SHOW CROSSING THE DESERT SOUTHWEST EARLY IN
THE WEEK...GRADUALLY MAKING ITS WAY OVER THE SOUTHERN PLAINS AND
INTO THE MID/UPPER MS VALLEY REGION LATE IN THE WEEK. THE MODELS
SEEM TO BE COMING INTO BETTER AGREEMENT WITH REGARD TO TIMING OF
THIS SYSTEM...WITH THE OUTLIER BEING THE FASTER OP GFS WHICH LACKS
SUPPORT FROM EVEN THE GFS ENSEMBLE MEAN. AS SUCH...TONIGHT`S
EXTENDED FORECAST LEANS HEAVILY ON THE 00Z ECMWF/GFS ENS MEAN/ECMWF
MEAN. THIS SOLUTION HOLDS OFF ON ANY WARM FRONTAL RAINS ACROSS THE
ARKLAMISS UNTIL LATE TUE NIGHT OR EARLY WED MORNING JUST BEFORE THE
WARM FRONT LIFTS ACROSS THE REGION. THE 00Z ECMWF IS QUITE
AGGRESSIVE WITH THE LOW LEVEL MOISTURE TRANSPORT SHOWING 65 DEGREE
SFC DEW POINTS AS FAR NORTH AS GLH/GWO BY WED EVENING JUST BEFORE
THE COLD FRONT PASSES. THIS MAY BE A BIT AGGRESSIVE...BUT ISN`T
TOTALLY OUT OF THE QUESTION GIVEN THE RICH POOL OF MOISTURE SHOWN
OFFSHORE OF BROWNSVILLE TX ON LATEST TPW SATELLITE PRODUCTS. THE
POTENTIAL FOR SFC BASED INSTABILITY AND ASSOCIATED RISK OF SEVERE
WEATHER (MAINLY IN THE FORM OF WIND GUSTS GIVEN "WARM" TEMPS ALOFT)
GOES UP IF WE CAN GET THAT KIND OF MOISTURE PULLED THIS FAR NORTH.
GIVEN THE FACT THAT SLOWER TIMING OF THIS SYSTEM OVERALL IS FAVORED
(ALLOWING MORE TIME FOR THE MOISTURE TO ARRIVE)...AND THE STRENGTH
OF THE AMBIENT WIND FIELDS...AM GOING TO ADD THE POTENTIAL FOR
STRONG WIND GUSTS TO THE HWO FOR THE SOUTHERN HALF OF THE CWA.
TIMING IS STILL A BIT OF A CHALLENGE...BUT LOOKS LIKE THE MAIN
TIMEFRAME FOR THE WORST OF THE WEATHER WILL BE LATE WED INTO
THU...AT LEAST FOR NOW. STAY TUNED FOR UPDATES ON THAT. THE ECMWF
ALSO SHOWS SOME POTENTIAL FOR TORNADOES ACROSS SOUTHERN AREAS GIVEN
STRONG LOW LEVEL SHEAR AHEAD OF THE CONVECTION...AND IF THE LOW
LEVEL MOISTURE CAN GET IN HERE...THIS ISN`T TOTALLY OUT OF THE
QUESTION. WILL BE KEEPING AN EYE ON THAT.
IN ADDITION TO THE RISK OF STRONG WIND GUSTS WILL BE THE POTENTIAL
FOR A QUICK ONE TO TWO INCHES OF RAINFALL WITH THIS SYSTEM. GIVEN
THE MOIST GROUND CONDITIONS IN PLACE WILL CONTINUE TO MENTION THE
HEAVY RAIN POTENTIAL IN THE HWO/GRAPHICS AS THIS COULD RE-AGGRAVATE
SOME MINOR RIVER FLOOD ISSUES.
THE RAINS LOOK TO CLEAR OUT BY LATE THU AS THE COLD FRONT PASSES...
BUT IT APPEARS THE FRONT WILL QUICKLY LIFT NORTH HEADED INTO FRI AS
STRONG HIGH PRESSURE REMAINS OVER THE EASTERN/SOUTHEASTERN CONUS.
THIS WILL ALLOW WARMER TEMPS TO RETURN OVER THE WEEKEND...
ACCOMPANIED BY LOW END RAIN CHANCES.
AS FOR TEMPS...GFS MOS HIGHS/LOWS WERE TWEAKED (QUITE A BIT AROUND
MID WEEK) TOWARD THE GENERALLY WARMER ECMWF MOS. POPS WERE ADJUSTED
TO FOLLOW ALONG WITH TIMING OFFERED BY THE ECMWF AS WELL. /BK/
&&
.AVIATION...VFR CEILINGS WILL PREVAIL THROUGH EARLY SUNDAY LOWERING
BRIEFLY TO 3-4K FEET AT TIMES. AREAS OF RAIN WILL CAN BE EXPECTED
TODAY...BRINGING BRIEF LOCALLY MVFR VISIBILITIES. /40/03
&&
.PRELIMINARY POINT TEMPS/POPS...
JACKSON 48 33 57 30 / 60 18 7 4
MERIDIAN 53 34 57 27 / 56 24 8 4
VICKSBURG 48 34 56 29 / 58 15 6 4
HATTIESBURG 56 38 60 34 / 54 24 12 6
NATCHEZ 48 35 56 32 / 60 18 7 5
GREENVILLE 48 34 53 28 / 53 11 6 3
GREENWOOD 48 32 55 26 / 54 13 7 4
&&
.JAN WATCHES/WARNINGS/ADVISORIES...
MS...NONE.
LA...NONE.
AR...NONE.
&&
$$
17/03/40/BK
AREA FORECAST DISCUSSION
NWS GRAND FORKS ND
639 AM CST SAT JAN 5 2013
.DISCUSSION...VISIBILITY ACROSS MUCH OF EASTERN NORTH DAKOTA HAS
IMPROVED AND NOW MAINLY A LOW STRATUS EVENT. WINDS EXPECTED TO
INCREASE FROM THE NORTH OVER THE NEXT FEW HOURS ENDING THE DENSE
FOG THREAT. WILL CANCEL THE ADVISORY.
&&
.AVIATION...NOT A HIGH CONFIDENCE FORECAST. AN AREA OF LIFR
CIGS WILL AFFECT EASTERN NORTH DAKOTA...BUT SHOULD ADVECT SOUTH
DURING THE MORNING HOURS AS WINDS BECOME NORTHERLY. BAND OF
MVFR/IFR CIGS EXPECTED TO PROPAGATE FROM WEST TO EAST THIS
EVENING. WILL NEED TO UPDATE WITH DETAILS WHEN/IF CONFIDENCE
INCREASES.
&&
.PREV DISCUSSION... /ISSUED 311 AM CST SAT JAN 5 2013/
SHORT TERM...CHALLENGES WILL BE FOG THIS MORNING...AND THEN
CLOUD TRENDS AND TEMPERATURES FOR THE REMAINDER OF THE PERIOD.
00Z MODELS IN DECENT AGREEMENT AND WILL USE A BLEND FOR DETAILS.
A WEAK SFC LOW IS APPROACHING FROM THE WEST AND WILL MOVE THROUGH
THE FA THIS MORNING. AN AREA OF DENSE FOG HAS DEVELOPED ACROSS
EASTERN NORTH DAKOTA. WINDS REMAIN LIGHT UNTIL AFTER THE SFC LOW
PASSES...SO HAVE ISSUED A DENSE FOG ADVISORY. 06Z HRRR HAS A GOOD
HANDLE ON CURRENT FOG CONDITIONS...AND IMPROVES VSBY ONCE WINDS
INCREASE FROM THE NORTH. LOW CONFIDENCE IN CLOUD TRENDS TODAY.
RAP/HRRR SHOW THE MOST PROBABLE SCENARIO...WITH MOST AREAS CLOUDY
TODAY AND POSSIBLE CLEARING ACROSS THE NORTH CENTRAL FA. MAX TEMPS
WILL BE TRICKY AND DEPENDENT ON CLOUDS...BUT DO NOT EXPECT A LARGE
RISE WITH NORTHERLY LOW LEVEL FLOW...AND VALUES SHOULD BE AROUND
NORMAL.
NORTHERLY UPPER LEVEL FLOW TONIGHT BECOMES MORE ZONAL BY LATER ON
SUNDAY. THERE WILL BE ANOTHER UPPER WAVE THAT SHOULD PROVIDE
CLOUDS AND MAYBE FLURRIES TO THE NE FA TONIGHT. A STRONGER SYSTEM
WILL MOVE ACROSS CANADA SUNDAY NIGHT THROUGH MONDAY NIGHT. NEAR
NORMAL TEMPERATURES THROUGH SUNDAY WILL BECOME ABOVE NORMAL
MONDAY. STRONGER WESTERLY LOW LEVEL FLOW EXPECTED ON MONDAY...AND
RAISED MAX TEMPS TO NEAR FREEZING. EXPECT ALL MEASURABLE PRECIP TO
REMAIN NORTH OF THE INTERNATIONAL BORDER.
LONG TERM (TUESDAY-FRIDAY)...THE OPERATIONAL MODELS HAVE COME
INTO SOMEWHAT BETTER AGREEMENT WITH THE PATTERN EVOLUTION DURING
THIS PERIOD. THE 00Z GFS HAS TRENDED TOWARDS THE SLOWER ECMWF
SOLUTION WITH A CLOSED LOW FORECAST TO EJECT FROM THE DESERT
SOUTHWEST INTO THE SOUTHERN PLAINS BY MID-WEEK. MEANWHILE...THE
NORTHERN PLAINS WILL STILL BE UNDER THE INFLUENCE OF A FAIRLY
ZONAL NORTHERN BRANCH OF THE JET FOR THE FIRST HALF OF THE PERIOD.
THIS WILL KEEP SEASONABLY MILD TEMPS IN PLACE FOR MUCH OF THE WORK
WEEK...WITH HIGHS IN THE 20S TO LOW 30S...AND LOWS IN THE TEENS.
THE 00Z GFS/ECMWF/GEM ALL BRING A SHORTWAVE TROUGH ACROSS THE
REGION ON TUESDAY...WITH THE GFS FARTHEST SOUTH AND THE ECMWF LESS
AMPLIFIED AND FARTHER NORTH WITH THE WAVE. A BIT OF LIGHT SNOW IS
POSSIBLE WITH THIS SYSTEM...ALTHOUGH MOISTURE AND FORCING WILL BE
LIMITED.
BY THURSDAY THE UPPER FLOW IS EXPECTED TO BECOME MORE SOUTHWESTERLY
IN RESPONSE TO THE DEVELOPMENT OF A BROAD LONGWAVE TROUGH ACROSS THE
WEST. WILL CONTINUE WITH LOW POPS THURSDAY WITH LOW-LEVEL BAROCLINIC
ZONE NEARBY AND WEAK WAVES RIPPLING THROUGH THE FLOW. UNCERTAINTY
REMAINS THOUGH REGARDING THE EVOLUTION OF THE UPPER TROUGH AS WELL
AS THE CLOSED LOW LIFTING OUT OF THE SOUTHERN PLAINS. COLDER TEMPS
WILL START TO WORK SOUTH LATE IN THE WEEK.
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...NONE.
MN...NONE.
&&
$$
TG/MAKOWSKI
AREA FORECAST DISCUSSION
NWS BISMARCK ND
320 AM CST SAT JAN 5 2013
.SHORT TERM...TODAY THROUGH SUNDAY...
THE HIGHLIGHTS OF THE SHORT TERM FORECAST ARE DENSE FOG ACROSS THE
EASTERN PORTIONS OF THE CWA THIS MORNING AND THE BEGINNING OF A
STRETCH OF ABOVE NORMAL TEMPERATURES STARING SUNDAY.
ISSUED A DENSE FOG ADVISORY FOR PORTIONS OF THE JAMES RIVER VALLEY
AND THE TURTLE MOUNTAINS THROUGH 16 UTC THIS MORNING. A STRONG
INVERSION ALONG AND EAST OF THE TERMINAL MORAINE HAS TRAPPED LOW
LEVEL MOISTURE AND LEAD TO THE DEVELOPMENT OF DENSE FOG. THE
LATEST HRRR VISIBILITY FORECASTS DEPICT THE DENSE FOG BECOMING
MORE WIDESPREAD EAST OF THE TERMINAL MORAINE...WHICH IS SUPPORTED
BY THE LATEST 11-3.9 SATELLITE TRENDS. WILL CONTINUE TO MONITOR
SHOULD A WESTWARD EXPANSION OF THE ADVISORY BECOME NECESSARY.
COOLER CONDITIONS ARE EXPECTED ACROSS WESTERN AND CENTRAL NORTH
DAKOTA TODAY IN THE WAKE OF A WEAK SURFACE LOW THAT WILL QUICKLY
PROPAGATE INTO CENTRAL MINNESOTA THIS AFTERNOON. THE OVERALL
SPREAD BETWEEN THE STATISTICAL AND DETERMINISTIC GUIDANCE IN
REGARDS TO HIGH TEMPERATURES FOR TODAY IS SMALL...AND WILL THUS
USE A BLEND. NORTHWESTERLY WIND GUSTS IN THE WAKE OF A COLD FRONT
MAY APPROACH 30 KTS THIS MORNING ACROSS SOUTHWEST NORTH
DAKOTA. HOWEVER...A RATHER SHALLOW POST FRONTAL MIXED LAYER
SUGGESTS THAT HIGHER MOMENTUM AIR WILL REMAIN IN THE INVERSION
LAYER...AND THUS...ADVISORY LEVEL WIND GUSTS OF 35+ KTS ARE NOT
ANTICIPATED. FINALLY...DID MAINTAIN THE MENTION OF ISOLATED
MORNING FLURRIES FOR MUCH OF THE AREA AS BROKEN DECKS OF LOW LEVEL
STRATUS IN THE WAKE OF THE LOW SPREAD ACROSS THE CWA.
TEMPERATURES CLIMB ON SUNDAY IN THE WARM SECTOR OF A SURFACE LOW
ACROSS EASTERN SASKATCHEWAN. GIVEN A LOW LEVEL WARM AIR ADVECTION
REGIME IN SOUTHERLY FLOW...THE CHALLENGE IS HOW MUCH WARM AIR CAN
BE MIXED TO THE SURFACE FROM AN INVERSION THAT WILL BE REINFORCED
BY THE SNOWPACK. THE TREND THE PAST COUPLE OF DAYS IN A SIMILIAR
SETUP HAS BEEN FOR THE STATISTICAL GUIDANCE TO BE ABOUT 3 TO 5
DEGREES TOO WARM...AND THE DETERMINISTIC MODELS TO ABOUT THE SAME
AMOUNT TOO COLD. THUS WILL USE A BLEND OF THE TWO GUIDANCE SUITES
WHICH YIELDS HIGHS IN THE LOWER 20S ACROSS THE JAMES RIVER VALLEY
WHERE THE LEAST MIXING IS EXPECTED...TO THE LOW TO MID 30S ACROSS
THE FAR WEST WHERE WINDS TURN SOUTHWEST AHEAD OF AN ADVANCING COLD
FRONT WHICH SHOULD ALLOW FOR GREATER MIXING HEIGHTS TO BE
ACHIEVED.
.LONG TERM...SUNDAY NIGHT THROUGH FRIDAY...
AS HAS BEEN THE CASE THIS ENTIRE WINTER SEASON...THE LATEST GFS HAS
NOW COME IN LINE WITH THE MORE STABLE ECMWF SOLUTION WITH RESPECT TO
THE SYNOPTIC PATTERN OVER THE CONUS FOR THE FIRST HALF OF NEXT WEEK.
THERE IS NOW HIGHER CONFIDENCE IN A DRY FORECAST MONDAY WITH A
CUT-OFF LOW TRAVERSING THE DESERT SOUTHWEST AND NORTHWESTERLY FLOW
ALOFT OVER THE NORTHERN PLAINS. ABOVE NORMAL TEMPERATURES ARE ALSO
EXPECTED MONDAY.
THE LATEST GFS/GEM/ECMWF ARE NOW CONSISTENT WITH PROGGING A
SHORTWAVE EJECTING FROM THE NORTHERN ROCKIES INTO NORTH DAKOTA
TUESDAY. IT APPEARS THE STRONGEST FORCING SHOULD DEVELOP OVER
NORTHERN NORTH DAKOTA TUESDAY. A SLIGHT CHANCE FOR SNOW SHOWERS IS
FORECAST FOR NORTHWEST AND NORTH CENTRAL AS A RESULT. TEMPS ARE
EXPECTED TO REMAIN ABOVE NORMAL TUESDAY.
ANOTHER SHORTWAVE IS EXPECTED TO CLIP THE NORTHWESTERN PORTIONS OF
THE STATE WEDNESDAY. THE THERMAL PROFILE AHEAD OF THIS FEATURE IS
PROGGED TO BE ONE CONDUCIVE FOR A WINTRY MIX OF PRECIPITATION
NORTHWEST LATE WEDNESDAY. ABOVE NORMAL TEMPERATURES ARE EXPECTED TO
CONTINUE.
BY THURSDAY...A POSITIVELY TILTED LONGWAVE TROUGH AXIS IS PROGGED TO
DEVELOP AND EXTEND FROM SASKATCHEWAN SOUTHWEST INTO CENTRAL
CALIFORNIA. ITS ATTENDANT COLD FRONT IS FORECAST TO SWEEP ACROSS THE
CWA THURSDAY BRINGING A SLIGHT CHANCE OF A WINTRY MIX OF
PRECIPITATION WEST AND CENTRAL. THE WINTRY MIX SHOULD TRANSITION TO
SNOW LATE THURSDAY AS MUCH COLDER ARCTIC AIR FILTERS INTO THE REGION.
DRY CONDITIONS ARE EXPECTED FRIDAY. HOWEVER...ARCTIC AIR WILL
CONTINUE TO INFILTRATE THE REGION WITH WELL BELOW NORMAL
TEMPERATURES EXPECTED FRIDAY.
&&
.AVIATION...
PATCHY DENSE FOG IS EXPECTED TO CONTINUE TO DEVELOP NEAR
KJMS THIS MORNING. PREVAILING CONDITIONS WILL LIKELY MVFR/IFR UNTIL
SUNRISE. FURTHERMORE...MVFR CIGS OVER KISN COULD EXPAND INTO
KMOT/KDIK/KBIS BY SUNRISE THIS MORNING. OTHERWISE...VFR CONDITIONS
ARE EXPECTED TO DEVELOP AREA WIDE BY LATE MORNING. INCREASING
NORTHWESTERLY WINDS COULD GUST UP TO 25 KNOTS BY MIDDAY. THE WINDS
SHOULD SUBSIDE BY THIS EVENING WITH VFR CONDITIONS CONTINUING
OVERNIGHT.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
DENSE FOG ADVISORY UNTIL 10 AM CST THIS MORNING FOR NDZ004-005-
013-023-025-037.
&&
$$
SHORT TERM...AYD
LONG TERM/AVIATION...TM
AREA FORECAST DISCUSSION
NWS GRAND FORKS ND
311 AM CST SAT JAN 5 2013
.SHORT TERM...CHALLENGES WILL BE FOG THIS MORNING...AND THEN
CLOUD TRENDS AND TEMPERATURES FOR THE REMAINDER OF THE PERIOD.
00Z MODELS IN DECENT AGREEMENT AND WILL USE A BLEND FOR DETAILS.
A WEAK SFC LOW IS APPROACHING FROM THE WEST AND WILL MOVE THROUGH
THE FA THIS MORNING. AN AREA OF DENSE FOG HAS DEVELOPED ACROSS
EASTERN NORTH DAKOTA. WINDS REMAIN LIGHT UNTIL AFTER THE SFC LOW
PASSES...SO HAVE ISSUED A DENSE FOG ADVISORY. 06Z HRRR HAS A GOOD
HANDLE ON CURRENT FOG CONDITIONS...AND IMPROVES VSBY ONCE WINDS
INCREASE FROM THE NORTH. LOW CONFIDENCE IN CLOUD TRENDS TODAY.
RAP/HRRR SHOW THE MOST PROBABLE SCENARIO...WITH MOST AREAS CLOUDY
TODAY AND POSSIBLE CLEARING ACROSS THE NORTH CENTRAL FA. MAX TEMPS
WILL BE TRICKY AND DEPENDENT ON CLOUDS...BUT DO NOT EXPECT A LARGE
RISE WITH NORTHERLY LOW LEVEL FLOW...AND VALUES SHOULD BE AROUND
NORMAL.
NORTHERLY UPPER LEVEL FLOW TONIGHT BECOMES MORE ZONAL BY LATER ON
SUNDAY. THERE WILL BE ANOTHER UPPER WAVE THAT SHOULD PROVIDE
CLOUDS AND MAYBE FLURRIES TO THE NE FA TONIGHT. A STRONGER SYSTEM
WILL MOVE ACROSS CANADA SUNDAY NIGHT THROUGH MONDAY NIGHT. NEAR
NORMAL TEMPERATURES THROUGH SUNDAY WILL BECOME ABOVE NORMAL
MONDAY. STRONGER WESTERLY LOW LEVEL FLOW EXPECTED ON MONDAY...AND
RAISED MAX TEMPS TO NEAR FREEZING. EXPECT ALL MEASURABLE PRECIP TO
REMAIN NORTH OF THE INTERNATIONAL BORDER.
.LONG TERM (TUESDAY-FRIDAY)...THE OPERATIONAL MODELS HAVE COME
INTO SOMEWHAT BETTER AGREEMENT WITH THE PATTERN EVOLUTION DURING
THIS PERIOD. THE 00Z GFS HAS TRENDED TOWARDS THE SLOWER ECMWF
SOLUTION WITH A CLOSED LOW FORECAST TO EJECT FROM THE DESERT
SOUTHWEST INTO THE SOUTHERN PLAINS BY MID-WEEK. MEANWHILE...THE
NORTHERN PLAINS WILL STILL BE UNDER THE INFLUENCE OF A FAIRLY
ZONAL NORTHERN BRANCH OF THE JET FOR THE FIRST HALF OF THE PERIOD.
THIS WILL KEEP SEASONABLY MILD TEMPS IN PLACE FOR MUCH OF THE WORK
WEEK...WITH HIGHS IN THE 20S TO LOW 30S...AND LOWS IN THE TEENS.
THE 00Z GFS/ECMWF/GEM ALL BRING A SHORTWAVE TROUGH ACROSS THE
REGION ON TUESDAY...WITH THE GFS FARTHEST SOUTH AND THE ECMWF LESS
AMPLIFIED AND FARTHER NORTH WITH THE WAVE. A BIT OF LIGHT SNOW IS
POSSIBLE WITH THIS SYSTEM...ALTHOUGH MOISTURE AND FORCING WILL BE
LIMITED.
BY THURSDAY THE UPPER FLOW IS EXPECTED TO BECOME MORE SOUTHWESTERLY
IN RESPONSE TO THE DEVELOPMENT OF A BROAD LONGWAVE TROUGH ACROSS THE
WEST. WILL CONTINUE WITH LOW POPS THURSDAY WITH LOW-LEVEL BAROCLINIC
ZONE NEARBY AND WEAK WAVES RIPPLING THROUGH THE FLOW. UNCERTAINTY
REMAINS THOUGH REGARDING THE EVOLUTION OF THE UPPER TROUGH AS WELL
AS THE CLOSED LOW LIFTING OUT OF THE SOUTHERN PLAINS. COLDER TEMPS
WILL START TO WORK SOUTH LATE IN THE WEEK.
&&
.AVIATION...NOT A HIGH CONFIDENCE FORECAST PAST 15Z. AN AREA OF
LIFR CONDITIONS WITH FOG WILL AFFECT KDVL AND KGFK THROUGH ABOUT
15Z. WINDS BECOME NORTHERLY TODAY...AND NOT SURE HOW WIDESPREAD
IFR/MVFR CIGS WILL BECOME. RAP/HRRR INDICATE THESE CIGS WILL
REMAIN WEST OF THE VALLEY AND AFFECT ONLY KDVL. WILL MONITOR
UPSTREAM OBSERVATIONS AND LATEST MODEL GUIDANCE AND INCLUDE IN THE
FORECAST WHEN/IF CONFIDENCE INCREASES.
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...DENSE FOG ADVISORY UNTIL 10 AM CST THIS MORNING FOR NDZ006>008-
014>016-024-026>030-038-039-054.
MN...NONE.
&&
$$
TG/MAKOWSKI
AREA FORECAST DISCUSSION FOR SOUTHEAST SD/SOUTHWEST MN/NORTHWEST IA
NWS SIOUX FALLS SD
946 AM CST SAT JAN 5 2013
.DISCUSSION.../ISSUED AT 946 AM CST/
WARM FRONT/TROUGH PUSHING TOWARD JAMES VALLEY THIS MORNING...BUT
COLD FRONT CLOSE ON ITS HEELS PUSHING THROUGH NORTHWEST THIRD OF
THE STATE ALREADY BY 15Z. FOR THE MOST PART...GOING FORECAST IS ON
TRACK AND NO SIGNIFICANT CHANGES ARE NEEDED. HAVE ADJUSTED SOME OF
THE HOURLY TEMPERATURE TRENDS TO FIT THE DIFFERENTIAL WARMTH WITH
ELEVATION AHEAD OF WIND SHIFT EARLY THIS MORNING. EXPECT AREAS TO
MIX OUT WITH SHIFT IN WINDS TO WEST AND NORTHWEST...BUT INCREASING
STRATUS AND COLD ADVECTION SHOULD LEAD TO FALLING TEMPS BEHIND THE
BOUNDARY THIS AFTERNOON...AS WELL AS A FEW FLURRIES. DID SLOW UP THE
ADVANCE OF CLOUDS/FLURRIES TO THE SOUTHEAST JUST A BIT. /CHAPMAN
&&
.AVIATION.../FOR THE 12Z TAF ISSUANCE/
VFR CONDITIONS EXPECTED TO CONTINUE THROUGH THE MORNING HOURS. A
COLD FRONT WILL PUSH THROUGH THE AREA THIS AFTERNOON. WINDS WILL
TURN BLUSTERY BEHIND THE FRONT WITH GUSTS OF 20 TO 30 KTS LIKELY.
AREA OF DEVELOPING MVFR AND IFR STRATUS OVER NORTH DAKOTA WILL
EXPAND AND HEAD SOUTH INTO OUR CWA THIS AFTERNOON. SPED UP THE
TIMING SOME IN THE TAFS BASED ON THE QUICKER RAP MODEL. THIS BRINGS
MVFR CIGS INTO KHON SHORTLY AFTER NOON...AND INTO KFSD AND KSUX BY
MID AFTERNOON. CURRENTLY THINKING MOST AREAS STAY IN THE 1-2KFT
RANGE...ALTHOUGH WILL HAVE TO MONITOR...AS SOME IFR CIGS ARE
POSSIBLE...ESPECIALLY TOWARDS EVENING. LOOKS LIKE WE SHOULD SEE
SCATTERED FLURRIES WITH THIS STRATUS...BUT VISIBILITY REDUCTIONS NOT
EXPECTED. STRATUS WILL CLEAR OUT TONIGHT FROM NORTHWEST TO
SOUTHEAST. SOME UNCERTAINTY ON WHEN THIS HAPPENS...BUT CURRENTLY
THINKING ALL TAF SITES ARE VFR BY AROUND OR SHORTLY AFTER MIDNIGHT.
VFR CONDITIONS WILL THEN CONTINUE THROUGH THE REMAINDER OF THE NIGHT
WITH DISSIPATING WINDS. /CHENARD
&&
.PREV DISCUSSION.../ISSUED AT 328 AM CST/
SHORT WAVE WILL DROP SOUTHEAST ACROSS CWA TODAY AND WILL PUSH
COLD FRONT SOUTHEAST ACROSS CWA. WILL MIX OUT WELL BEHIND THIS FRONT
WITH THE COLD AIR ADVECTION...BUT STILL WILL SEE HIGHS NEAR NORMAL.
THIS WAVE WILL BRING A CHANCE OF FLURRIES TO NORTHEAST HALF OF CWA
THIS AFTERNOON AS IT SLIDES SOUTHEAST INTO MINNESOTA. WILL ALSO SEE
GUSTY WIND OF 20 TO 30 MPH BEHIND FRONT AND MAT PRODUCE SOME BLOWING
SNOW ACROSS NORTHEAST CWA. HOWEVER...SNOW COVER NOT THAT DEEP AND
WITH DITCHES NOT FULL OF SNOW...DO NOT SEE MUCH OF A PROBLEM WITH
BLOWING SNOW.
SURFACE RIDGE WILL PUSH EAST ACROSS CWA TONIGHT...AND WITH CLEARING
SKIES AND DECREASING WINDS...WILL SEE LOWS DIP INTO THE SINGLE
DIGITS.
WARM AIR WILL BEGIN TO RETURN TO CWA ON SUNDAY AS RIDGE AXIS ALOFT
SHIFTS TO THE EAST. THIS WILL ALLOW THE BEST WARMING ACROSS THE WEST
ON SUNDAY WITH HIGHS BACK INTO THE 30S ACROSS THE SOUTHWEST. SOUTH
TO SOUTHWEST WINDS SUNDAY NIGHT WILL HELP HOLD TEMPERATURES UP
ACROSS THE CWA WITH WINDS GUSTING TO 30 TO 35 MPH ACROSS THE BUFFALO
RIDGE.
THE MILD WEATHER WILL CONTINUE MONDAY THROUGH WEDNESDAY WITH A MILD
WEST TO SOUTHWEST LOW LEVEL FLOW. GFS APPEARS TO BE OVER DOING WAVE
ON TUESDAY AND PREFER THE MORE TAME EC/GEM SOLUTION. EITHER
WAY...ABOVE NORMAL TEMPERATURES EXPECTED. HOWEVER...SNOW
COVER...ESPECIALLY NORTH OF INTERSTATE 90 WILL HOLD TEMPERATURES
DOWN A BIT...BUT SHOULD STILL MIX OUT INTO LOWER 30S...WITH LOWER
40S ACROSS SOUTHWEST CWA BY TUESDAY AND WEDNESDAY. SNOW COVER ACROSS
NEBRASKA WILL ALSO HAVE SOME IMPACT ACROSS SOUTHWEST CWA. OTHERWISE
IF THERE WAS NO SNOW COVER THERE...COULD HIT THE LOWER 50S.
MODELS DIVERGE A BIT FOR LATE WEDNESDAY NIGHT AND THURSDAY WITH WAVE
LIFTING NORTHEAST OUT OF SOUTHERN PLAINS. GFS MUCH FASTER AND
FURTHER SOUTHEAST...WHILE ECMWF AND GEM SLOWER AND FURTHER NORTH.
GFS HAS NOT HANDLED SOUTHERN SYSTEMS VERY WELL THIS WINTER AND
PREFER MORE STABLE ECMWF. STILL...THIS SYSTEM APPEARS THAT IT WILL
GRAZE THE SOUTHEAST CWA EVEN WITH ITS FURTHEST NORTH SOLUTION. WILL
BE A RELATIVELY WARM SYSTEM AND COULD SEE A MIX OF LIGHT FREEZING
RAIN OR SNOW ACROSS THE FAR SOUTHEAST LATE WEDNESDAY NIGHT. WILL
KEEP THE 20% TO 30% POPS GOING ACROSS THE SOUTHEAST ON THURSDAY.
COLDER AIR WILL FILTER BACK INTO CWA FOR FRIDAY BEHIND THIS SYSTEM.
MODELS ALL OVER THE PLACE FOR NEXT WEEKEND...WITH THE TYPICAL GFS
STORM CREATING SOLUTIONS AFTER DAY 7. ECMWF MUCH WEAKER AND USUALLY
MORE CORRECT.
&&
.FSD WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
MN...NONE.
IA...NONE.
NE...NONE.
&&
$$
AREA FORECAST DISCUSSION FOR SOUTHEAST SD/SOUTHWEST MN/NORTHWEST IA
NWS SIOUX FALLS SD
534 AM CST SAT JAN 5 2013
.DISCUSSION.../ISSUED AT 328 AM CST/
SHORT WAVE WILL DROP SOUTHEAST ACROSS CWA TODAY AND WILL PUSH
COLD FRONT SOUTHEAST ACROSS CWA. WILL MIX OUT WELL BEHIND THIS FRONT
WITH THE COLD AIR ADVECTION...BUT STILL WILL SEE HIGHS NEAR NORMAL.
THIS WAVE WILL BRING A CHANCE OF FLURRIES TO NORTHEAST HALF OF CWA
THIS AFTERNOON AS IT SLIDES SOUTHEAST INTO MINNESOTA. WILL ALSO SEE
GUSTY WIND OF 20 TO 30 MPH BEHIND FRONT AND MAT PRODUCE SOME BLOWING
SNOW ACROSS NORTHEAST CWA. HOWEVER...SNOW COVER NOT THAT DEEP AND
WITH DITCHES NOT FULL OF SNOW...DO NOT SEE MUCH OF A PROBLEM WITH
BLOWING SNOW.
SURFACE RIDGE WILL PUSH EAST ACROSS CWA TONIGHT...AND WITH CLEARING
SKIES AND DECREASING WINDS...WILL SEE LOWS DIP INTO THE SINGLE
DIGITS.
WARM AIR WILL BEGIN TO RETURN TO CWA ON SUNDAY AS RIDGE AXIS ALOFT
SHIFTS TO THE EAST. THIS WILL ALLOW THE BEST WARMING ACROSS THE WEST
ON SUNDAY WITH HIGHS BACK INTO THE 30S ACROSS THE SOUTHWEST. SOUTH
TO SOUTHWEST WINDS SUNDAY NIGHT WILL HELP HOLD TEMPERATURES UP
ACROSS THE CWA WITH WINDS GUSTING TO 30 TO 35 MPH ACROSS THE BUFFALO
RIDGE.
THE MILD WEATHER WILL CONTINUE MONDAY THROUGH WEDNESDAY WITH A MILD
WEST TO SOUTHWEST LOW LEVEL FLOW. GFS APPEARS TO BE OVER DOING WAVE
ON TUESDAY AND PREFER THE MORE TAME EC/GEM SOLUTION. EITHER
WAY...ABOVE NORMAL TEMPERATURES EXPECTED. HOWEVER...SNOW
COVER...ESPECIALLY NORTH OF INTERSTATE 90 WILL HOLD TEMPERATURES
DOWN A BIT...BUT SHOULD STILL MIX OUT INTO LOWER 30S...WITH LOWER
40S ACROSS SOUTHWEST CWA BY TUESDAY AND WEDNESDAY. SNOW COVER ACROSS
NEBRASKA WILL ALSO HAVE SOME IMPACT ACROSS SOUTHWEST CWA. OTHERWISE
IF THERE WAS NO SNOW COVER THERE...COULD HIT THE LOWER 50S.
MODELS DIVERGE A BIT FOR LATE WEDNESDAY NIGHT AND THURSDAY WITH WAVE
LIFTING NORTHEAST OUT OF SOUTHERN PLAINS. GFS MUCH FASTER AND
FURTHER SOUTHEAST...WHILE ECMWF AND GEM SLOWER AND FURTHER NORTH.
GFS HAS NOT HANDLED SOUTHERN SYSTEMS VERY WELL THIS WINTER AND
PREFER MORE STABLE ECMWF. STILL...THIS SYSTEM APPEARS THAT IT WILL
GRAZE THE SOUTHEAST CWA EVEN WITH ITS FURTHEST NORTH SOLUTION. WILL
BE A RELATIVELY WARM SYSTEM AND COULD SEE A MIX OF LIGHT FREEZING
RAIN OR SNOW ACROSS THE FAR SOUTHEAST LATE WEDNESDAY NIGHT. WILL
KEEP THE 20% TO 30% POPS GOING ACROSS THE SOUTHEAST ON THURSDAY.
COLDER AIR WILL FILTER BACK INTO CWA FOR FRIDAY BEHIND THIS SYSTEM.
MODELS ALL OVER THE PLACE FOR NEXT WEEKEND...WITH THE TYPICAL GFS
STORM CREATING SOLUTIONS AFTER DAY 7. ECMWF MUCH WEAKER AND USUALLY
MORE CORRECT.
&&
.AVIATION.../FOR THE 12Z TAF ISSUANCE/
VFR CONDITIONS EXPECTED TO CONTINUE THROUGH THE MORNING HOURS. A
COLD FRONT WILL PUSH THROUGH THE AREA THIS AFTERNOON. WINDS WILL
TURN BLUSTERY BEHIND THE FRONT WITH GUSTS OF 20 TO 30 KTS LIKELY.
AREA OF DEVELOPING MVFR AND IFR STRATUS OVER NORTH DAKOTA WILL
EXPAND AND HEAD SOUTH INTO OUR CWA THIS AFTERNOON. SPED UP THE
TIMING SOME IN THE TAFS BASED ON THE QUICKER RAP MODEL. THIS BRINGS
MVFR CIGS INTO KHON SHORTLY AFTER NOON...AND INTO KFSD AND KSUX BY
MID AFTERNOON. CURRENTLY THINKING MOST AREAS STAY IN THE 1-2KFT
RANGE...ALTHOUGH WILL HAVE TO MONITOR...AS SOME IFR CIGS ARE
POSSIBLE...ESPECIALLY TOWARDS EVENING. LOOKS LIKE WE SHOULD SEE
SCATTERED FLURRIES WITH THIS STRATUS...BUT VISIBILITY REDUCTIONS NOT
EXPECTED. STRATUS WILL CLEAR OUT TONIGHT FROM NORTHWEST TO
SOUTHEAST. SOME UNCERTAINTY ON WHEN THIS HAPPENS...BUT CURRENTLY
THINKING ALL TAF SITES ARE VFR BY AROUND OR SHORTLY AFTER MIDNIGHT.
VFR CONDITIONS WILL THEN CONTINUE THROUGH THE REMAINDER OF THE NIGHT
WITH DISSIPATING WINDS. /CHENARD
&&
.FSD WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
MN...NONE.
IA...NONE.
NE...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS PUEBLO CO
249 PM MST SAT JAN 5 2013
.SHORT TERM...
(TONIGHT AND SUNDAY)
SHORTWAVE PASSING OFF TO THE NORTHEAST HAS SENT A DRY COLD FRONT
THROUGH THE SE PLAINS. WINDS NOT TERRIBLY STRONG WITH IT...AND
MIXING HAS ACTUALLY WARMED TEMPS A FEW DEGREES IN SPITE OF THE CAA
BEHIND THE FRONT...WITH KLAA AT 45 DEGREES SO FAR...COMPARED TO
YESTERDAY`S HIGH OF ONLY 39. MEANWHILE...THE SAN LUIS VALLEY HAS
BEEN STRUGGLING TO WARM...WITH KALS ONLY AT 11 DEGREES AS OF 21Z.
TONIGHT...CLEAR SKIES...DRY SFC DEW POINTS...AND SNOW COVER IN SOME
PLACES WILL LEAD TO ANOTHER COLD NIGHT. CAN`T FIND A REASON WHY
KALS WON`T DROP TO AROUND -30 AGAIN TONIGHT...SO TOOK MIN TEMPS
THERE WELL BELOW GUIDANCE. OTHER CHALLENGE WILL BE POTENTIAL FOR
FOG IN THE SAN LUIS VALLEY. THIS DIDN`T HAPPEN LAST NIGHT...OR AT
LEAST VISIBILITY AT KALS DIDN`T DROP BELOW 5 MILES...THOUGH WE DID
SEE SOME LIFR STRATUS IN THE WEB CAMS AND IN THE CEILOMETER DATA FROM
ASOS. NAM12 SOUNDINGS SATURATE AT THE SFC AROUND 02Z AND REMAIN SO
THROUGH 15Z SUN. THE LOCAL 4 KM WRF ALSO INDICATES POTENTIAL FOR
FOG...AND HRRR SHOWS SFC RHS APPROACHING 80% BY 09Z SUN. RAP
SOUNDINGS BY CONTRAST LOOK FAIRLY DRY...AND NEITHER THE MET NOR MAV
GUIDANCE HAVE ANY INDICATION OF FOG. WILL THROW PATCHY FOG INTO THE
GRIDS FOR NOW...BUT WILL DELAY THIS UNTIL AFTER 06Z. HUNCH IS IT
WON`T OCCUR UNTIL AFTER 09-10Z BASED ON WHAT HAPPENED LAST
NIGHT...AND SHOULD BREAK BY 15-16Z ON SUN.
FLOW ALOFT BECOMES MORE SOUTHWESTERLY ON SUNDAY AS THE UPPER RIDGE
SHIFTS EASTWARD AND NEXT UPPER LOW MOVES INTO CA. LEE TROF
DEEPENS IN RESPONSE WITH WINDS AIDING IN BETTER MIXING ALONG THE
I-25 CORRIDOR. CURRENT FORECAST WITH 40S AND LOWER 50S LOOK
REASONABLE ACROSS THE PLAINS. MEANWHILE...DRY CONDITIONS WILL
CONTINUE EVERYWHERE. ITS POSSIBLE THAT KALS COULD SEE SOME
MODERATING TEMPERATURES AS WELL IF WINDS CAN MIX IN...BUT GIVEN THE
STRONG INVERSIONS...KEPT TEMPS BELOW GUIDANCE VALUES WITH SOME MINOR
IMPROVEMENT. -KT
.LONG TERM...
(SUNDAY NIGHT-SATURDAY)
SUNDAY NIGHT-MONDAY...LATEST MODELS CONTINUE TO BE IN GOOD AGREEMENT
OF DEVELOPING SPLIT FLOW PATTERN INTO THE MIDDLE WEEK. CLOSED LOW IN
THE DEVELOPING SOUTHERN STREAM ACROSS THE SOUTHEASTERN NEVADA SUNDAY
AFTERNOON PROGGED TO DIVE INTO OLD MEXICO THROUGH THE DAY MONDAY AS
A MINOR WAVE EMBEDDED IN THE ZONAL FLOW ACROSS NORTHERN TIER OF
STATES TRANSLATES ACROSS THE NORTHERN ROCKIES AND INTO THE NORTHERN
HIGH PLAINS. OVERNIGHT LOWS...ESPECIALLY IN THE SAN LUIS VALLEY
REMAIN TRICKY WITH SOME INCREASE IN HIGH LEVEL MOISTURE SPREADING
ACROSS THE REGION...THOUGH DOES NOT LOOK TO BE ENOUGH TO KEEP TEMPS
FROM TANKING...AND HAVE GONE BELOW GUIDANCE VALUES IN THE HIGH MT
VALLEYS. BOTH SYSTEMS REMAIN TOO FAR AWAY FROM THE AREA TO PRODUCE
ANY PRECIPITATION...THOUGH WILL SEE SLIGHTLY COOLER TEMPERATURES
AS PASSING NORTHERN STREAM SYSTEM SENDS A WEAK BACKDOOR COLD FRONT
ACROSS EASTERN COLORADO MONDAY MORNING.
MONDAY NIGHT-WEDNESDAY NIGHT...WEAK FLOW PROGGED ACROSS THE AREA
THROUGH THIS PERIOD AS OLD MEXICO LOW SLOWLY LIFTS OUT INTO THE
SOUTHERN HIGH PLAINS. MODELS DIFFER ON TRACK WITH THE EC A TAD
FURTHER NORTH AND WEST WITH SAID SYSTEM ACROSS THE NORTH CENTRAL
TEXAS PANHANDLE WEDNESDAY NIGHT AND PRINTS OUT SOME LIGHT QPF
ACROSS THE FAR SE PLAINS. WITH THE WEAK FLOW ALOFT...HAVE GONE BELOW
GUIDANCE FOR HIGHS THROUGH THE PERIOD...WITH TEMPERATURES MAINLY IN
THE 40S TO LOWER 50S ACROSS THE PLAINS AND 30S ACROSS THE HIGHER
TERRAIN. AGAIN...HAVE STAYED WELL BELOW GUIDANCE FOR THE SAN LUIS
VALLEY AS NOT ENOUGH WIND TO SCOUR OUT THE COLD AIRMASS IN PLACE.
THURSDAY-SATURDAY...LATEST MODELS CONTINUE TO INDICATE A BETTER
CHANCE OF WIDESPREAD PRECIPITATION INTO THE EARLY WEEKEND AS PACIFIC
ENERGY DIGGING INTO THE GREAT BASIN ON THURSDAY SLOWLY LIFTS OUT
ACROSS THE ROCKIES THROUGH SATURDAY. SOME CONCERN THAT STRONG
BACKSIDE JET ACROSS THE GREAT BASIN COULD DIG THE SYSTEM FURTHER
SOUTH THAN CURRENT PROJECTIONS...SO HAVE KEPT CURRENT MODEL
CONSENSUS SOLUTION WHICH GIVES CHANCE POPS ACROSS THE CONTINENTAL
DIVIDE THURSDAY NIGHT AND FRIDAY...WITH CHANCE AND SLIGHT CHANCE
POPS SPREADING ACROSS THE REST OF THE HIGHER TERRAIN THROUGH THE
EASTERN PLAINS FRIDAY THROUGH SATURDAY. TEMPERATURES WILL ALSO BE
TRENDING BACK BELOW SEASONAL AVERAGES BY FRIDAY AND SATURDAY. -MW
&&
.AVIATION...
CLEAR SKIES AND VFR CONDITIONS EXPECTED AT KPUB AND KCOS THROUGH
SUNDAY. CHALLENGE WILL BE THE POTENTIAL FOR LIFR CIGS AND POSSIBLY
VIS IN FZFG AT KALS OVERNIGHT. MODELS DIFFER IN WHETHER THIS WILL
OR WILL NOT OCCUR...AND CONFIDENCE IS LOW. PLAN TO DELAY LIFR
CONDITIONS UNTIL AFTER 09Z IN NEXT TAF ISSUANCE. ANY LIFR CIGS/VIS
SHOULD BREAK BETWEEN 15-16Z...WITH VFR CONDITIONS AND LIGHT WINDS
THROUGH SUNDAY. -KT
&&
.PUB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
31/23
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
157 PM CST SAT JAN 5 2013
.DISCUSSION...
1254 PM CST
UPDATE FOR THIS AFTERNOON...
UPPER LOW THAT WAS OVER THE TX AND OK PANHANDLE AREAS DURING THE
PREDAWN HAS REFORMED FURTHER TO THE NE THIS MORNING AND WAS
CURRENTLY MOVING NORTHEASTWARD OVER NW AND N CENTRAL MO.
MEANWHILE...A SHORT WAVE TROF WAS QUICKLY DROPPING SOUTHEASTWARD
ACROSS SD AND NE BEHIND THE LIFTING MID MS VALLEY UPPER LOW.
MODELS SHOW THE UPPER LOW GRADUALLY WEAKENING DURING THE
AFTERNOON AS IT REACHES NORTHERN IL BY 00Z. MODELS ALSO SHOW THE
PLAINS SHORT WAVE TROF CONTINUING TO MN AND NORTHERN IA BY 00Z
AND BEGINNING TO MERGE WITH THE WEAKENING UPPER LOW.
SATELLITE LOOP SHOWS COOLING TOPS MOVING ACROSS THE N HALF OF IL
IN IR...WHILE VIS LOOP SHOWS TEXTURED CLOUDS WITH A BIT OF A
CONVECTIVE NATURE TO THEM ACROSS MOST OF THE REGION. RADAR
COMPOSITE SHOWS ECHOES FROM FAR SE IA EASTWARD TO GENERALLY OVER
THE I-74 CORRIDOR THEN CURVING S AND SSW TO THE S TIP OF IL.
BASED ON CURRENT AND RECENT METARS SNOW IS FALLING FROM THE MID
TO BACK EDGE OF THE ECHO COVERAGE WHILE UNDER THE LEADING EDGE OF
THE ECHOES THE LOWER LAYERS ARE TOO DRY TO PREVENT METEORS FROM
EVAPORATING BEFORE REACHING THE SURFACE.
WHILE A RATHER UNUSUAL SET UP OF LOWER AND MID LEVEL COLD AIR
ADVECTION IS OCCURRING WITH THE SW FLOW AHEAD OF THE APPROACHING
DISTURBANCE THERE IS AN AREA OF MID LEVEL LEVEL ISENTROPIC UPGLIDE
INDICATED FROM NE MO TO NORTHERN IL MATCHING THE MORE INTENSE
ECHOES ACROSS THE NORTHERN PORTIONS OF IL. THE AREA OF MID LEVEL
LIFT IS PROGGED BY THE RAP TO BE OVER N CENTRAL AND NE IL INTO SE
WI AT 00Z.
AS THE AREA OF MID LEVEL LIFT CONTINUES TO MOVE OVER THE LOCAL
FORECAST AREA AND THE LOWER LEVELS MOISTEN THIS AFTERNOON
ANTICIPATE LIGHT SNOW BREAKING OUT. A FEW LOCATIONS UPSTREAM HAVE
REPORTED A BRIEF PERIOD OF VISIBILITY BETWEEN 3/4 AND 1 1/4 MI AS
A MORE INTENSE RADAR ECHO MOVED ACROSS THE SITE. ACCUMULATIONS
DURING THE AFTERNOON WILL BE AN INCH OR LESS AS OVERALL THE
SNOWFALL WILL LIGHT AND WITH TEMPERATURES IN THE LOWER AND MID
30S THE REST OF THE AFTERNOON WHAT DOES FALL WILL BE AT LEAST
PARTIALLY MELTING.
TRS
.PREV DISCUSSION...
334 AM CST
MAIN FORECAST CONCERN THIS MORNING WILL BE DETAILS OF SNOWFALL
ACROSS THE AREA THIS AFTERNOON AND EVENING...AS WELL AS A BIG WARM
UP IN STORE NEXT WEEK.
TODAY AND TONIGHT...CONFIDENCE HIGH
THIS MORNING...SATELLITE ANALYSIS SHOWS UPPER LOW SPINNING ACROSS
THE TX/OK PANHANDLE REGION WITH LEAD VORT MAX LIFTING NORTHEAST
ACROSS EASTERN OK. A SECOND NORTHERN STREAM SHORTWAVE IS MOVING
SOUTHEAST ACROSS NORTHERN ALBERTA. AT THE SURFACE...EXPANSIVE
RIDGING SPANS FROM THE MID APPALACHIAN RANGE SOUTHWEST INTO SOUTHERN
TEXAS...CUTTING OFF ACCESS TO ANY GULF MOISTURE.
MODELS ARE IN VERY GOOD AGREEMENT TODAY REGARDING THE EVOLUTION OF
THE CLOSED LOW OVER THE CENTRAL PLAINS THIS MORNING...INTO AN OPEN
WAVE AS IT MOVES ACROSS THE MID TO UPPER MISSISSIPPI VALLEY THIS
AFTERNOON...AND CONTINUES TO DAMPEN IS IT MOVES EAST OF THE FORECAST
AREA THIS EVENING. DESPITE MODERATE FORCING THAT IS ASSOCIATED WITH
THE DCVA OF THE UPPER WAVE AS IT MOVES ACROSS NORTHERN ILLINOIS
LATE THIS AFTERNOON...THE AIRMASS IN PLACE IS VERY DRY AND BELIEVE
MODELS SATURATE THE COLUMN TOO QUICKLY. EVENING RAOBS FROM ILX/DVN
INDICATED PWATS OF 0.20-0.23...HOWEVER GUIDANCE SHOWS RAPID
SATURATION OF THE COLUMN OVER JUST AN HOUR OR TWO. RAW GFS/NAM
SNOWFALL TOTALS AMOUNT TO ONE TO JUST OVER TWO INCHES FROM ROUGHLY
OTTAWA TO NEAR DOWNTOWN CHICAGO. PLACEMENT OF THE AXIS OF HEAVIEST
SNOW IS OKAY...HOWEVER SUSPECT THAT SNOWFALL WILL NOT BEGIN IN
EARNEST UNTIL CLOSER TO 20-21Z NEAR OTTAWA AND 22-23Z THIS EVENING
FOR CHICAGO...WHICH WILL COINCIDE WITH BETTER FORCING WITHIN THE
DENDRITIC GROWTH ZONE. WITH WBZ HEIGHTS NEAR THE SURFACE...AM NOT
TOO CONCERNED ABOUT MIXED PRECIP AT THE ONSET. TEMPERATURES
WARMING INTO THE MID 30S TODAY MAY ALSO MAKE IT A LITTLE TOUGH FOR
SNOW TO ACCUMULATE INITIALLY...SO ONLY EXPECT A DUSTING TO AROUND
HALF AN INCH THROUGH THIS EVENING.
DRIER MID LEVEL AIR QUICKLY MOVES IN BEHIND THE DEPARTING FIRST
UPPER WAVE THIS EVENING...AND WHILE THERE MAY BE A SHORT WINDOW
WHERE SEEDER FEEDER MECHANICS CONTINUE TO SUPPLY NUCLEI FOR SNOW
GROWTH...THE MID LEVEL DRY LAYER QUICKLY DEEPENS BY AROUND 03-04Z
LEAVING SHALLOW LOW LEVEL MOISTURE WITH TOPS AROUND -5C. THIS MAY
LEAD TO A CHANGE OVER TO FREEZING DRIZZLE AS SURFACE TEMPS FALL
BELOW THE FREEZING MARK...HOWEVER NAM GUIDANCE IN PARTICULAR IS
NOTORIOUS FOR HOLDING ONTO LOW LEVEL MOISTURE TOO LONG...AND WITH
GFS INDICATING SLIGHTLY DRIER AIR NEAR THE SURFACE...DOESNT LOOK
LIKE THIS WILL BE A WIDESPREAD/ACCUMULATING ICE AT THIS TIME.
MOTORISTS AND PEDESTRIANS SHOULD STILL BE WARY OF A FEW SLICK SPOTS
THIS EVENING AND OVERNIGHT.
SUNDAY THROUGH TUESDAY...CONFIDENCE HIGH
THE SECOND NORTHERN STREAM WAVE WILL MOVE ACROSS THE REGION SUNDAY
MORNING...AND SHOULD BE DEPARTING THE CWA BY EARLY AFTERNOON. EXPECT
EVEN LESS MOISTURE WITH THIS WAVE...SO AT BEST MAY SQUEEZE OUT A FEW
FLURRIES. SKIES SHOULD BEGIN TO CLEAR FROM THE WEST DURING THE
AFTERNOON AS ANTICYCLONIC FLOW/SURFACE RIDGING BEGIN TO WORK INTO
THE AREA. TEMPERATURES WILL BEGIN TO MODERATE THROUGH EARLY NEXT
WEEK AND EXPECT DRY CONDITIONS THROUGH TUESDAY WITH THE SURFACE
RIDGE MOVING OFF TO OUR EAST. FOR MONDAY AND TUESDAY...EXPECT MAX
TEMPS TO REBOUND BACK IN THE UPPER 30S TO AROUND 40 WITH LOW TEMPS
IN THE MID TO UPPER 20S.
WEDNESDAY THROUGH FRIDAY...CONFIDENCE LOW
WHILE THERE IS GENERAL AGREEMENT IN THE MODELS THROUGH TUESDAY
REGARDING RIDGING BUILDING ACROSS THE EASTERN CONUS WHILE A DEEP LOW
CUTS OFF OVER THE SOUTHWEST CONUS...SIGNIFICANT TIMING DIFFERENCES
DEVELOP IN THE MODELS BY WEDNESDAY. THE ECMWF HAS BEEN CONSISTENTLY
A SLOWER AND DEEPER MODEL WHILE THE GFS HAS TRENDED TOWARDS THIS
SOLUTION...WITH THE GEM A COMPROMISE. BY THURSDAY EXPECT THE LOW TO
LIFT NORTHEAST SOMEWHERE ACROSS THE MIDWEST...WITH HUGE IMPLICATIONS
ON THE TEMP/PRECIP FORECAST FROM MIDWEEK ON. GIVEN THE UNCERTAINTY
IN THE TRACK OF THE SYSTEM...DIDNT MAKE BIG CHANGES FROM GOING
FORECAST...THOUGH DID STAY SLIGHTLY WARMER THAN MODEL CONSENSUS
FAVORING THE WARMER SOLUTION OF THE MORE CONSISTENT ECMWF...WHICH
WOULD SUGGEST WARM AND RAINY CONDITIONS ESPECIALLY THURSDAY AS THE
LOW TAPS INTO GULF MOISTURE WITH STRONG WARM ADVECTION/MOISTURE
TRANSPORT UP THE MISSISSIPPI VALLEY. JUST TO HIGHLIGHT THE
DIFFERENCES IN SOLUTIONS...THE ECMWF SUGGESTS TEMPERATURES ON
THURSDAY IN THE MID TO UPPER 50S SOUTH OF I-80 WITH UPPER 40S TO MID
50S TO THE NORTH. MEANWHILE...THE GFS HAS MID 30S ACROSS THE ENTIRE
CWA THURSDAY. WILL HAVE TO CONTINUE TO MONITOR MODEL TRENDS WITH
THIS SYSTEM.
BMD
//PREV DISCUSSION...
334 AM CST
MAIN FORECAST CONCERN THIS MORNING WILL BE DETAILS OF SNOWFALL
ACROSS THE AREA THIS AFTERNOON AND EVENING...AS WELL AS A BIG WARM
UP IN STORE NEXT WEEK.
TODAY AND TONIGHT...CONFIDENCE HIGH
THIS MORNING...SATELLITE ANALYSIS SHOWS UPPER LOW SPINNING ACROSS
THE TX/OK PANHANDLE REGION WITH LEAD VORT MAX LIFTING NORTHEAST
ACROSS EASTERN OK. A SECOND NORTHERN STREAM SHORTWAVE IS MOVING
SOUTHEAST ACROSS NORTHERN ALBERTA. AT THE SURFACE...EXPANSIVE
RIDGING SPANS FROM THE MID APPALACHIAN RANGE SOUTHWEST INTO SOUTHERN
TEXAS...CUTTING OFF ACCESS TO ANY GULF MOISTURE.
MODELS ARE IN VERY GOOD AGREEMENT TODAY REGARDING THE EVOLUTION OF
THE CLOSED LOW OVER THE CENTRAL PLAINS THIS MORNING...INTO AN OPEN
WAVE AS IT MOVES ACROSS THE MID TO UPPER MISSISSIPPI VALLEY THIS
AFTERNOON...AND CONTINUES TO DAMPEN IS IT MOVES EAST OF THE FORECAST
AREA THIS EVENING. DESPITE MODERATE FORCING THAT IS ASSOCIATED WITH
THE DCVA OF THE UPPER WAVE AS IT MOVES ACROSS NORTHERN ILLINOIS
LATE THIS AFTERNOON...THE AIRMASS IN PLACE IS VERY DRY AND BELIEVE
MODELS SATURATE THE COLUMN TOO QUICKLY. EVENING RAOBS FROM ILX/DVN
INDICATED PWATS OF 0.20-0.23...HOWEVER GUIDANCE SHOWS RAPID
SATURATION OF THE COLUMN OVER JUST AN HOUR OR TWO. RAW GFS/NAM
SNOWFALL TOTALS AMOUNT TO ONE TO JUST OVER TWO INCHES FROM ROUGHLY
OTTAWA TO NEAR DOWNTOWN CHICAGO. PLACEMENT OF THE AXIS OF HEAVIEST
SNOW IS OKAY...HOWEVER SUSPECT THAT SNOWFALL WILL NOT BEGIN IN
EARNEST UNTIL CLOSER TO 20-21Z NEAR OTTAWA AND 22-23Z THIS EVENING
FOR CHICAGO...WHICH WILL COINCIDE WITH BETTER FORCING WITHIN THE
DENDRITIC GROWTH ZONE. WITH WBZ HEIGHTS NEAR THE SURFACE...AM NOT
TOO CONCERNED ABOUT MIXED PRECIP AT THE ONSET. TEMPERATURES
WARMING INTO THE MID 30S TODAY MAY ALSO MAKE IT A LITTLE TOUGH FOR
SNOW TO ACCUMULATE INITIALLY...SO ONLY EXPECT A DUSTING TO AROUND
HALF AN INCH THROUGH THIS EVENING.
DRIER MID LEVEL AIR QUICKLY MOVES IN BEHIND THE DEPARTING FIRST
UPPER WAVE THIS EVENING...AND WHILE THERE MAY BE A SHORT WINDOW
WHERE SEEDER FEEDER MECHANICS CONTINUE TO SUPPLY NUCLEI FOR SNOW
GROWTH...THE MID LEVEL DRY LAYER QUICKLY DEEPENS BY AROUND 03-04Z
LEAVING SHALLOW LOW LEVEL MOISTURE WITH TOPS AROUND -5C. THIS MAY
LEAD TO A CHANGE OVER TO FREEZING DRIZZLE AS SURFACE TEMPS FALL
BELOW THE FREEZING MARK...HOWEVER NAM GUIDANCE IN PARTICULAR IS
NOTORIOUS FOR HOLDING ONTO LOW LEVEL MOISTURE TOO LONG...AND WITH
GFS INDICATING SLIGHTLY DRIER AIR NEAR THE SURFACE...DOESNT LOOK
LIKE THIS WILL BE A WIDESPREAD/ACCUMULATING ICE AT THIS TIME.
MOTORISTS AND PEDESTRIANS SHOULD STILL BE WARY OF A FEW SLICK SPOTS
THIS EVENING AND OVERNIGHT.
SUNDAY THROUGH TUESDAY...CONFIDENCE HIGH
THE SECOND NORTHERN STREAM WAVE WILL MOVE ACROSS THE REGION SUNDAY
MORNING...AND SHOULD BE DEPARTING THE CWA BY EARLY AFTERNOON. EXPECT
EVEN LESS MOISTURE WITH THIS WAVE...SO AT BEST MAY SQUEEZE OUT A FEW
FLURRIES. SKIES SHOULD BEGIN TO CLEAR FROM THE WEST DURING THE
AFTERNOON AS ANTICYCLONIC FLOW/SURFACE RIDGING BEGIN TO WORK INTO
THE AREA. TEMPERATURES WILL BEGIN TO MODERATE THROUGH EARLY NEXT
WEEK AND EXPECT DRY CONDITIONS THROUGH TUESDAY WITH THE SURFACE
RIDGE MOVING OFF TO OUR EAST. FOR MONDAY AND TUESDAY...EXPECT MAX
TEMPS TO REBOUND BACK IN THE UPPER 30S TO AROUND 40 WITH LOW TEMPS
IN THE MID TO UPPER 20S.
WEDNESDAY THROUGH FRIDAY...CONFIDENCE LOW
WHILE THERE IS GENERAL AGREEMENT IN THE MODELS THROUGH TUESDAY
REGARDING RIDGING BUILDING ACROSS THE EASTERN CONUS WHILE A DEEP LOW
CUTS OFF OVER THE SOUTHWEST CONUS...SIGNIFICANT TIMING DIFFERENCES
DEVELOP IN THE MODELS BY WEDNESDAY. THE ECMWF HAS BEEN CONSISTENTLY
A SLOWER AND DEEPER MODEL WHILE THE GFS HAS TRENDED TOWARDS THIS
SOLUTION...WITH THE GEM A COMPROMISE. BY THURSDAY EXPECT THE LOW TO
LIFT NORTHEAST SOMEWHERE ACROSS THE MIDWEST...WITH HUGE IMPLICATIONS
ON THE TEMP/PRECIP FORECAST FROM MIDWEEK ON. GIVEN THE UNCERTAINTY
IN THE TRACK OF THE SYSTEM...DIDNT MAKE BIG CHANGES FROM GOING
FORECAST...THOUGH DID STAY SLIGHTLY WARMER THAN MODEL CONSENSUS
FAVORING THE WARMER SOLUTION OF THE MORE CONSISTENT ECMWF...WHICH
WOULD SUGGEST WARM AND RAINY CONDITIONS ESPECIALLY THURSDAY AS THE
LOW TAPS INTO GULF MOISTURE WITH STRONG WARM ADVECTION/MOISTURE
TRANSPORT UP THE MISSISSIPPI VALLEY. JUST TO HIGHLIGHT THE
DIFFERENCES IN SOLUTIONS...THE ECMWF SUGGESTS TEMPERATURES ON
THURSDAY IN THE MID TO UPPER 50S SOUTH OF I-80 WITH UPPER 40S TO MID
50S TO THE NORTH. MEANWHILE...THE GFS HAS MID 30S ACROSS THE ENTIRE
CWA THURSDAY. WILL HAVE TO CONTINUE TO MONITOR MODEL TRENDS WITH
THIS SYSTEM.
BMD
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 20Z...
* WET LIGHT SNOW BEGINNING LIKELY WITHIN 2030-2100Z AND LASTING
FOR A FEW HOURS WITH A PERIOD OF TEMPORARY MORE INTENSE RATES
AND IFR VISBYS.
* TEMPORARY MVFR CIGS BECOMING WIDESPREAD BY LATER THIS EVE.
* A PROBABLE PERIOD OF DRIZZLE...WHICH DEPENDING ON TEMPS COULD BE
FREEZING DRIZZLE.
* GUSTY S WINDS GRADUALLY VEERING TO WNW BY SUNDAY MORNING.
//DISCUSSION...UPDATED 20Z...
AXIS OF SNOW CONTINUES TO SHIFT ENE TOWARD THE CHICAGOLAND TAF
SITES. SOON AFTER START THIS WILL LIKELY SEE TEMPORARY IFR
VISIBILITY...AND SUCH HAS BEEN OBSERVED HERE AT THE WEATHER
FORECAST OFFICE. CONFIDENCE DIMINISHES BEYOND THIS...ALTHOUGH A
PERIOD OF DRIZZLE LOOKS SLIGHTLY MORE PROBABLE THIS EVE...AND
TEMPERATURES WOULD LIKELY BE ABOVE FREEZING AT THAT TIME.
//PREV DISCUSSION...UPDATED 18Z...
A STRONG UPPER LEVEL DISTURBANCE ACROSS NORTHERN MO EARLY THIS
AFTERNOON IS SHIFTING NORTHEAST TOWARD THE AREA AND WILL MOVE
OVERHEAD CHICAGO AROUND 00Z...WITH ANOTHER ONE ACROSS WESTERN MN
TO MOVE OVER ON ITS HEELS OVERNIGHT. THE FIRST WAVE WILL CONTINUE
TO USHER AN ARC OF SNOW SHOWERS NORTHWARD ACROSS IL AND INTO NW
IN. PERIODIC VISIBILITIES OF UNDER ONE AND A HALF MILES HAVE BEEN
OBSERVED...HOWEVER THESE HAVE BEEN QUITE BRIEF. THESE TEMPORARY
LOWER VISIBILITIES WILL PERSIST WITH THIS AREA THROUGH THE
AFTERNOON...AND EXPECT THAT THE RADAR ECHOES WILL FILL IN SOME
BEHIND THIS LEADING ARC. A BRIEF MIX WITH RAIN IS POSSIBLE AT
FIRST...BUT THE MAIN PRECIP TYPE SHOULD BE WET AND POSSIBLY LARGE
SNOWFLAKES. TOTAL SNOW ACCUMULATION WILL LIKELY BE BETWEEN A FEW
TENTHS OF AN INCH TO HIGHEST CASE SCENARIO AROUND AN INCH. AS THIS
INITIAL WAVE PASSES...A PERIOD OF SOMEWHAT WEAK FORCING WILL BE IN
PLACE...BUT ENOUGH SO THAT TEMPORARY LIGHT SNOW/FLURRIES AS WELL
AS DRIZZLE WILL BE POSSIBLE. TEMPERATURES WILL FALL TO BELOW
FREEZING POTENTIALLY AS EARLY AS 03Z-06Z...BUT DEFINITELY BY EARLY
OVERNIGHT CREATING THE POTENTIAL FOR FZDZ IF INDEED DRIZZLE CAN
UNFOLD. AS THE SECOND UPPER LEVEL DISTURBANCE MOVES JUST TO THE
NORTH...SCATTERED LIGHT SNOW SHOWERS MAY BE SEEN LATE TONIGHT INTO
EARLY SUNDAY MORNING. WINDS WILL BE GUSTY FROM THE S VEERING TO
THE WNW BY DAYBREAK SUNDAY MORNING BEHIND A SURFACE COLD FRONT.
//ORD AND MDW CONFIDENCE...UPDATED 20Z...
* HIGH CONFIDENCE IN SNOW OCCURRING AND TIMING...WITH HIGH
CONFIDENCE IN TEMPORARY IFR VISIBILITY...THOUGH MEDIUM
CONFIDENCE IN DURATION.
* LOW CONFIDENCE IN CIGS TONIGHT. CIGS VERY WELL COULD BE HIGHER
WITH ONLY PATCHES OF SUB 2000 FT CIGS...BUT IF DRIZZLE IS
WIDESPREAD...IFR CIGS ARE LIKELY.
* LOW CONFIDENCE IN FZDZ AT ANY ONE TAF SITE.
* HIGH CONFIDENCE IN WIND TRENDS.
//OUTLOOK FOR ORD/MDW FOR 00Z MONDAY-12Z SATURDAY...UPDATED 12Z...
SUNDAY NIGHT THROUGH WEDNESDAY...VFR.
WEDNESDAY NIGHT AND THURSDAY...CHANCE SHRA/DZ AND MVFR WITH IFR
POSSIBLE.
FRIDAY...SLIGHT CHANCE SHRA...MVFR POSSIBLE.
MTF
&&
.MARINE...
257 AM CST
A TROUGH OF LOW PRESSURE EXTENDS ACROSS NORTHERN LAKE MICHIGAN FROM
A LOW CENTERED OVER MAINE EARLY THIS MORNING. HIGH PRESSURE WILL
SPREAD ACROSS THE LAKE FROM THE NORTHWEST THIS MORNING THEN QUICKLY
BE PUSHED EASTWARD AS WEAK LOW PRESSURE CURRENTLY OVER THE WESTERN
DAKOTAS MOVES IN. WILL SEE A STEADY DECREASE IN WIND SPEEDS THROUGH
THE MORNING AS THE HIGH ARRIVES BEFORE AN INCREASE IN WEST AND
SOUTHWEST WINDS COMMENCES THIS AFTERNOON AS THE LOW ARRIVES FROM
THE WEST. EXPECT THE HIGHEST SPEEDS ACROSS THE SOUTHERN HALF OF
THE LAKE. THE LOW WILL SHIFT EAST OF THE LAKE SUNDAY MORNING
BRINGING A SHIFT TO NORTHWEST WINDS WITH SPEEDS REMAINING ELEVATED
INTO THE AFTERNOON BEFORE DROPPING OFF DURING THE EVENING AS HIGH
PRESSURE RETURNS. THIS HIGH WILL QUICKLY SHIFT EAST AS WELL WITH
STRONG LOW PRESSURE MOVING ACROSS THE CANADIAN PRAIRIES BEHIND IT.
THE PRESSURE GRADIENT WILL STRENGTHEN CONSIDERABLY ON MONDAY WITH
SOUTHWEST WINDS INCREASING THROUGH THE DAY. THE LOW WILL PASS
NORTH OF THE LAKE AND MAY DEEPEN SLIGHTLY AS IT DOES SO MONDAY
NIGHT. AS A RESULT...MID RANGE SOUTHWEST GALES ARE LOOKING MORE
LIKELY BY LATE MONDAY AFTERNOON BUT EASE TUESDAY MORNING AS THE
LOW MOVES INTO NORTHERN QUEBEC AND WEAK HIGH PRESSURE RIDGING
ARRIVES. WILL BUMP FORECAST WORDING UP TO GALES AND CARRY 40 KT
NORTH FOR NOW BUT THERE IS SOME POTENTIAL TO BE CLOSER TO 45 KT
FOR AT LEAST A SHORT TIME MONDAY EVENING IF THE LOW DEEPENS
SUFFICIENTLY. WINDS SHOULD BE CLOSER TO 30-35 KT SOUTH. BEYOND
THAT CONFIDENCE LOWERS BUT THE PATTERN LOOKS TO REMAIN ACTIVE WITH
ANOTHER LOW PASSING NORTH OF THE LAKE TUESDAY NIGHT. THE SOUTHERN
STREAM OF FLOW LOOKS TO BECOME MORE ACTIVE AND LOW PRESSURE MAY
MOVE UP FROM THE SOUTHWEST LATE NEXT WEEK.
MDB
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
1254 PM CST SAT JAN 5 2013
.DISCUSSION...
1254 PM CST
UPDATE FOR THIS AFTERNOON...
UPPER LOW THAT WAS OVER THE TX AND OK PANHANDLE AREAS DURING THE
PREDAWN HAS REFORMED FURTHER TO THE NE THIS MORNING AND WAS
CURRENTLY MOVING NORTHEASTWARD OVER NW AND N CENTRAL MO.
MEANWHILE...A SHORT WAVE TROF WAS QUICKLY DROPPING SOUTHEASTWARD
ACROSS SD AND NE BEHIND THE LIFTING MID MS VALLEY UPPER LOW.
MODELS SHOW THE UPPER LOW GRADUALLY WEAKENING DURING THE
AFTERNOON AS IT REACHES NORTHERN IL BY 00Z. MODELS ALSO SHOW THE
PLAINS SHORT WAVE TROF CONTINUING TO MN AND NORTHERN IA BY 00Z
AND BEGINNING TO MERGE WITH THE WEAKENING UPPER LOW.
SATELLITE LOOP SHOWS COOLING TOPS MOVING ACROSS THE N HALF OF IL
IN IR...WHILE VIS LOOP SHOWS TEXTURED CLOUDS WITH A BIT OF A
CONVECTIVE NATURE TO THEM ACROSS MOST OF THE REGION. RADAR
COMPOSITE SHOWS ECHOES FROM FAR SE IA EASTWARD TO GENERALLY OVER
THE I-74 CORRIDOR THEN CURVING S AND SSW TO THE S TIP OF IL.
BASED ON CURRENT AND RECENT METARS SNOW IS FALLING FROM THE MID
TO BACK EDGE OF THE ECHO COVERAGE WHILE UNDER THE LEADING EDGE OF
THE ECHOES THE LOWER LAYERS ARE TOO DRY TO PREVENT METEORS FROM
EVAPORATING BEFORE REACHING THE SURFACE.
WHILE A RATHER UNUSUAL SET UP OF LOWER AND MID LEVEL COLD AIR
ADVECTION IS OCCURRING WITH THE SW FLOW AHEAD OF THE APPROACHING
DISTURBANCE THERE IS AN AREA OF MID LEVEL LEVEL ISENTROPIC UPGLIDE
INDICATED FROM NE MO TO NORTHERN IL MATCHING THE MORE INTENSE
ECHOES ACROSS THE NORTHERN PORTIONS OF IL. THE AREA OF MID LEVEL
LIFT IS PROGGED BY THE RAP TO BE OVER N CENTRAL AND NE IL INTO SE
WI AT 00Z.
AS THE AREA OF MID LEVEL LIFT CONTINUES TO MOVE OVER THE LOCAL
FORECAST AREA AND THE LOWER LEVELS MOISTEN THIS AFTERNOON
ANTICIPATE LIGHT SNOW BREAKING OUT. A FEW LOCATIONS UPSTREAM HAVE
REPORTED A BRIEF PERIOD OF VISIBILITY BETWEEN 3/4 AND 1 1/4 MI AS
A MORE INTENSE RADAR ECHO MOVED ACROSS THE SITE. ACCUMULATIONS
DURING THE AFTERNOON WILL BE AN INCH OR LESS AS OVERALL THE
SNOWFALL WILL LIGHT AND WITH TEMPERATURES IN THE LOWER AND MID
30S THE REST OF THE AFTERNOON WHAT DOES FALL WILL BE AT LEAST
PARTIALLY MELTING.
TRS
.PREV DISCUSSION...
334 AM CST
MAIN FORECAST CONCERN THIS MORNING WILL BE DETAILS OF SNOWFALL
ACROSS THE AREA THIS AFTERNOON AND EVENING...AS WELL AS A BIG WARM
UP IN STORE NEXT WEEK.
TODAY AND TONIGHT...CONFIDENCE HIGH
THIS MORNING...SATELLITE ANALYSIS SHOWS UPPER LOW SPINNING ACROSS
THE TX/OK PANHANDLE REGION WITH LEAD VORT MAX LIFTING NORTHEAST
ACROSS EASTERN OK. A SECOND NORTHERN STREAM SHORTWAVE IS MOVING
SOUTHEAST ACROSS NORTHERN ALBERTA. AT THE SURFACE...EXPANSIVE
RIDGING SPANS FROM THE MID APPALACHIAN RANGE SOUTHWEST INTO SOUTHERN
TEXAS...CUTTING OFF ACCESS TO ANY GULF MOISTURE.
MODELS ARE IN VERY GOOD AGREEMENT TODAY REGARDING THE EVOLUTION OF
THE CLOSED LOW OVER THE CENTRAL PLAINS THIS MORNING...INTO AN OPEN
WAVE AS IT MOVES ACROSS THE MID TO UPPER MISSISSIPPI VALLEY THIS
AFTERNOON...AND CONTINUES TO DAMPEN IS IT MOVES EAST OF THE FORECAST
AREA THIS EVENING. DESPITE MODERATE FORCING THAT IS ASSOCIATED WITH
THE DCVA OF THE UPPER WAVE AS IT MOVES ACROSS NORTHERN ILLINOIS
LATE THIS AFTERNOON...THE AIRMASS IN PLACE IS VERY DRY AND BELIEVE
MODELS SATURATE THE COLUMN TOO QUICKLY. EVENING RAOBS FROM ILX/DVN
INDICATED PWATS OF 0.20-0.23...HOWEVER GUIDANCE SHOWS RAPID
SATURATION OF THE COLUMN OVER JUST AN HOUR OR TWO. RAW GFS/NAM
SNOWFALL TOTALS AMOUNT TO ONE TO JUST OVER TWO INCHES FROM ROUGHLY
OTTAWA TO NEAR DOWNTOWN CHICAGO. PLACEMENT OF THE AXIS OF HEAVIEST
SNOW IS OKAY...HOWEVER SUSPECT THAT SNOWFALL WILL NOT BEGIN IN
EARNEST UNTIL CLOSER TO 20-21Z NEAR OTTAWA AND 22-23Z THIS EVENING
FOR CHICAGO...WHICH WILL COINCIDE WITH BETTER FORCING WITHIN THE
DENDRITIC GROWTH ZONE. WITH WBZ HEIGHTS NEAR THE SURFACE...AM NOT
TOO CONCERNED ABOUT MIXED PRECIP AT THE ONSET. TEMPERATURES
WARMING INTO THE MID 30S TODAY MAY ALSO MAKE IT A LITTLE TOUGH FOR
SNOW TO ACCUMULATE INITIALLY...SO ONLY EXPECT A DUSTING TO AROUND
HALF AN INCH THROUGH THIS EVENING.
DRIER MID LEVEL AIR QUICKLY MOVES IN BEHIND THE DEPARTING FIRST
UPPER WAVE THIS EVENING...AND WHILE THERE MAY BE A SHORT WINDOW
WHERE SEEDER FEEDER MECHANICS CONTINUE TO SUPPLY NUCLEI FOR SNOW
GROWTH...THE MID LEVEL DRY LAYER QUICKLY DEEPENS BY AROUND 03-04Z
LEAVING SHALLOW LOW LEVEL MOISTURE WITH TOPS AROUND -5C. THIS MAY
LEAD TO A CHANGE OVER TO FREEZING DRIZZLE AS SURFACE TEMPS FALL
BELOW THE FREEZING MARK...HOWEVER NAM GUIDANCE IN PARTICULAR IS
NOTORIOUS FOR HOLDING ONTO LOW LEVEL MOISTURE TOO LONG...AND WITH
GFS INDICATING SLIGHTLY DRIER AIR NEAR THE SURFACE...DOESNT LOOK
LIKE THIS WILL BE A WIDESPREAD/ACCUMULATING ICE AT THIS TIME.
MOTORISTS AND PEDESTRIANS SHOULD STILL BE WARY OF A FEW SLICK SPOTS
THIS EVENING AND OVERNIGHT.
SUNDAY THROUGH TUESDAY...CONFIDENCE HIGH
THE SECOND NORTHERN STREAM WAVE WILL MOVE ACROSS THE REGION SUNDAY
MORNING...AND SHOULD BE DEPARTING THE CWA BY EARLY AFTERNOON. EXPECT
EVEN LESS MOISTURE WITH THIS WAVE...SO AT BEST MAY SQUEEZE OUT A FEW
FLURRIES. SKIES SHOULD BEGIN TO CLEAR FROM THE WEST DURING THE
AFTERNOON AS ANTICYCLONIC FLOW/SURFACE RIDGING BEGIN TO WORK INTO
THE AREA. TEMPERATURES WILL BEGIN TO MODERATE THROUGH EARLY NEXT
WEEK AND EXPECT DRY CONDITIONS THROUGH TUESDAY WITH THE SURFACE
RIDGE MOVING OFF TO OUR EAST. FOR MONDAY AND TUESDAY...EXPECT MAX
TEMPS TO REBOUND BACK IN THE UPPER 30S TO AROUND 40 WITH LOW TEMPS
IN THE MID TO UPPER 20S.
WEDNESDAY THROUGH FRIDAY...CONFIDENCE LOW
WHILE THERE IS GENERAL AGREEMENT IN THE MODELS THROUGH TUESDAY
REGARDING RIDGING BUILDING ACROSS THE EASTERN CONUS WHILE A DEEP LOW
CUTS OFF OVER THE SOUTHWEST CONUS...SIGNIFICANT TIMING DIFFERENCES
DEVELOP IN THE MODELS BY WEDNESDAY. THE ECMWF HAS BEEN CONSISTENTLY
A SLOWER AND DEEPER MODEL WHILE THE GFS HAS TRENDED TOWARDS THIS
SOLUTION...WITH THE GEM A COMPROMISE. BY THURSDAY EXPECT THE LOW TO
LIFT NORTHEAST SOMEWHERE ACROSS THE MIDWEST...WITH HUGE IMPLICATIONS
ON THE TEMP/PRECIP FORECAST FROM MIDWEEK ON. GIVEN THE UNCERTAINTY
IN THE TRACK OF THE SYSTEM...DIDNT MAKE BIG CHANGES FROM GOING
FORECAST...THOUGH DID STAY SLIGHTLY WARMER THAN MODEL CONSENSUS
FAVORING THE WARMER SOLUTION OF THE MORE CONSISTENT ECMWF...WHICH
WOULD SUGGEST WARM AND RAINY CONDITIONS ESPECIALLY THURSDAY AS THE
LOW TAPS INTO GULF MOISTURE WITH STRONG WARM ADVECTION/MOISTURE
TRANSPORT UP THE MISSISSIPPI VALLEY. JUST TO HIGHLIGHT THE
DIFFERENCES IN SOLUTIONS...THE ECMWF SUGGESTS TEMPERATURES ON
THURSDAY IN THE MID TO UPPER 50S SOUTH OF I-80 WITH UPPER 40S TO MID
50S TO THE NORTH. MEANWHILE...THE GFS HAS MID 30S ACROSS THE ENTIRE
CWA THURSDAY. WILL HAVE TO CONTINUE TO MONITOR MODEL TRENDS WITH
THIS SYSTEM.
BMD
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 18Z...
* WET LIGHT SNOW BEGINNING LIKELY WITHIN 2100-2130Z AND LASTING
FOR A FEW HOURS WITH A PERIOD OF TEMPORARY MORE INTENSE RATES
AND IFR VISBYS.
* TEMPORARY MVFR CIGS BECOMING WIDESPREAD BY LATER THIS EVE.
* A CHANCE FOR FREEZING DRIZZLE LATE THIS EVE INTO OVERNIGHT.
* GUSTY S WINDS GRADUALLY VEERING TO WNW BY SUNDAY MORNING.
//DISCUSSION...UPDATED 18Z...
A STRONG UPPER LEVEL DISTURBANCE ACROSS NORTHERN MO EARLY THIS
AFTERNOON IS SHIFTING NORTHEAST TOWARD THE AREA AND WILL MOVE
OVERHEAD CHICAGO AROUND 00Z...WITH ANOTHER ONE ACROSS WESTERN MN
TO MOVE OVER ON ITS HEELS OVERNIGHT. THE FIRST WAVE WILL CONTINUE
TO USHER AN ARC OF SNOW SHOWERS NORTHWARD ACROSS IL AND INTO NW
IN. PERIODIC VISIBILITIES OF UNDER ONE AND A HALF MILES HAVE BEEN
OBSERVED...HOWEVER THESE HAVE BEEN QUITE BRIEF. THESE TEMPORARY
LOWER VISIBILITIES WILL PERSIST WITH THIS AREA THROUGH THE
AFTERNOON...AND EXPECT THAT THE RADAR ECHOES WILL FILL IN SOME
BEHIND THIS LEADING ARC. A BRIEF MIX WITH RAIN IS POSSIBLE AT
FIRST...BUT THE MAIN PRECIP TYPE SHOULD BE WET AND POSSIBLY LARGE
SNOWFLAKES. TOTAL SNOW ACCUMULATION WILL LIKELY BE BETWEEN A FEW
TENTHS OF AN INCH TO HIGHEST CASE SCENARIO AROUND AN INCH. AS THIS
INITIAL WAVE PASSES...A PERIOD OF SOMEWHAT WEAK FORCING WILL BE IN
PLACE...BUT ENOUGH SO THAT TEMPORARY LIGHT SNOW/FLURRIES AS WELL
AS DRIZZLE WILL BE POSSIBLE. TEMPERATURES WILL FALL TO BELOW
FREEZING POTENTIALLY AS EARLY AS 03Z-06Z...BUT DEFINITELY BY EARLY
OVERNIGHT CREATING THE POTENTIAL FOR FZDZ IF INDEED DRIZZLE CAN
UNFOLD. AS THE SECOND UPPER LEVEL DISTURBANCE MOVES JUST TO THE
NORTH...SCATTERED LIGHT SNOW SHOWERS MAY BE SEEN LATE TONIGHT INTO
EARLY SUNDAY MORNING. WINDS WILL BE GUSTY FROM THE S VEERING TO
THE WNW BY DAYBREAK SUNDAY MORNING BEHIND A SURFACE COLD FRONT.
//ORD AND MDW CONFIDENCE...UPDATED 18Z...
* HIGH CONFIDENCE IN SNOW OCCURRING. MEDIUM CONFIDENCE IN TIMING
AND LOWEST VISBYS AND CIGS.
* LOW CONFIDENCE IN CIGS TONIGHT. CIGS VERY WELL COULD BE HIGHER
WITH ONLY PATCHES OF SUB 2000 FT CIGS...BUT IF DRIZZLE WERE TO
OCCUR...EVEN DOWN TO IFR IS PROBABLE.
* LOW CONFIDENCE IN FZDZ AT ANY ONE TAF SITE.
* HIGH CONFIDENCE IN WIND TRENDS.
//OUTLOOK FOR ORD/MDW FOR 00Z MONDAY-12Z SATURDAY...UPDATED 18Z...
SUNDAY NIGHT THROUGH WEDNESDAY...VFR.
WEDNESDAY NIGHT AND THURSDAY...CHANCE SHRA/DZ AND MVFR WITH IFR
POSSIBLE.
FRIDAY...SLIGHT CHANCE SHRA...MVFR POSSIBLE.
MTF
&&
.MARINE...
257 AM CST
A TROUGH OF LOW PRESSURE EXTENDS ACROSS NORTHERN LAKE MICHIGAN FROM
A LOW CENTERED OVER MAINE EARLY THIS MORNING. HIGH PRESSURE WILL
SPREAD ACROSS THE LAKE FROM THE NORTHWEST THIS MORNING THEN QUICKLY
BE PUSHED EASTWARD AS WEAK LOW PRESSURE CURRENTLY OVER THE WESTERN
DAKOTAS MOVES IN. WILL SEE A STEADY DECREASE IN WIND SPEEDS THROUGH
THE MORNING AS THE HIGH ARRIVES BEFORE AN INCREASE IN WEST AND
SOUTHWEST WINDS COMMENCES THIS AFTERNOON AS THE LOW ARRIVES FROM
THE WEST. EXPECT THE HIGHEST SPEEDS ACROSS THE SOUTHERN HALF OF
THE LAKE. THE LOW WILL SHIFT EAST OF THE LAKE SUNDAY MORNING
BRINGING A SHIFT TO NORTHWEST WINDS WITH SPEEDS REMAINING ELEVATED
INTO THE AFTERNOON BEFORE DROPPING OFF DURING THE EVENING AS HIGH
PRESSURE RETURNS. THIS HIGH WILL QUICKLY SHIFT EAST AS WELL WITH
STRONG LOW PRESSURE MOVING ACROSS THE CANADIAN PRAIRIES BEHIND IT.
THE PRESSURE GRADIENT WILL STRENGTHEN CONSIDERABLY ON MONDAY WITH
SOUTHWEST WINDS INCREASING THROUGH THE DAY. THE LOW WILL PASS
NORTH OF THE LAKE AND MAY DEEPEN SLIGHTLY AS IT DOES SO MONDAY
NIGHT. AS A RESULT...MID RANGE SOUTHWEST GALES ARE LOOKING MORE
LIKELY BY LATE MONDAY AFTERNOON BUT EASE TUESDAY MORNING AS THE
LOW MOVES INTO NORTHERN QUEBEC AND WEAK HIGH PRESSURE RIDGING
ARRIVES. WILL BUMP FORECAST WORDING UP TO GALES AND CARRY 40 KT
NORTH FOR NOW BUT THERE IS SOME POTENTIAL TO BE CLOSER TO 45 KT
FOR AT LEAST A SHORT TIME MONDAY EVENING IF THE LOW DEEPENS
SUFFICIENTLY. WINDS SHOULD BE CLOSER TO 30-35 KT SOUTH. BEYOND
THAT CONFIDENCE LOWERS BUT THE PATTERN LOOKS TO REMAIN ACTIVE WITH
ANOTHER LOW PASSING NORTH OF THE LAKE TUESDAY NIGHT. THE SOUTHERN
STREAM OF FLOW LOOKS TO BECOME MORE ACTIVE AND LOW PRESSURE MAY
MOVE UP FROM THE SOUTHWEST LATE NEXT WEEK.
MDB
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS GOODLAND KS
1055 AM MST SAT JAN 5 2013
.SHORT TERM...(TODAY THROUGH SUNDAY)
ISSUED AT 236 AM MST SAT JAN 5 2013
04Z WATER VAPOR IMAGERY AND RAP ANALYSIS INDICATED UPPER LEVEL LOW
CIRCULATION CENTERED OVER THE OKLAHOMA PANHANDLE MOVING
NORTHEAST...WITH A SECOND SHORT WAVE TROUGH DIVING TO THE SOUTHEAST
ACROSS THE NORTHERN PLAINS. FOR THE MOST PART...00Z SOUNDINGS HAD
WARMED AND DRIED FROM 24 HOURS AGO WITH THE ONLY EXCEPTION BEING
H75-H5 MOISTENING AT DDC IN ADVANCE OF SOUTHERN LOW. MOISTENING WAS
LIMITED TO THIS LEVEL HOWEVER...WITH LARGE SUB CLOUD DRY LATER
NOTED.
TODAY-SUNDAY...TROUGH TO THE SOUTH WILL GRADUALLY LIFT TO THE
NORTHEAST THIS MORNING AS NEXT SYSTEM APPROACHES FROM THE NORTH.
WHILE THERE IS A BIT OF ASCENT EXPECTED...SYSTEMS FOR THE MOST PART
DO NOT BRING ANY MEANINGFUL INFLUX OF MOISTURE TO THE AREA. WITH
OBSERVED SOUNDINGS AROUND THE AREA INDICATING VERY DRY
CONDITIONS...ESPECIALLY BELOW H7...LEADS ME TO THINK DEPARTING
SYSTEM WILL LEAD TO MUCH MORE THAN A PERIOD OF MID CLOUDS...ALTHOUGH
WILL MONITOR. SYSTEM APPROACHING FROM THE NORTH WILL HAVE SIMILAR
MOISTURE AVAILABILITY ISSUES DURING THE AFTERNOON AS IT MOVES ACROSS
THE AREA. MAIN CONCERN WITH THIS SECOND SYSTEM WILL BE THE SHARP
INCREASE IN WIND SPEEDS OFF OF THE SURFACE...ESPECIALLY AS
SUBSIDENCE INCREASES IN THE AFTERNOON. HAVE BUMPED UP THE WINDS INTO
THE 15 TO 25 MPH CATEGORY FOR THE TIME BEING...AS THE LINGERING
IMPACT OF SNOW COVER MAKES CONFIDENCE IN DEEP MIXING TOO LOW TO
BRING DOWN HIGHER SPEEDS. STRONG SUBSIDENCE WILL OVERSPREAD THE AREA
TONIGHT AS SHORT WAVE RIDGE MOVES OVER THE AREA. THIS WILL LEAD TO
CONTINUED DRY AND MOSTLY CLEAR CONDITIONS THROUGH SUNDAY MORNING
BEFORE CLOUDS BEGIN TO INCREASE LATE IN THE AFTERNOON AS RIDGE
SHIFTS TO THE EAST OF THE AREA. OVERALL CURRENT FORECAST LOOKS
REASONABLE CONSIDERING LATEST SUITE OF DATA AND ONLY MADE A FEW
MINOR CHANGES TO TEMPS.
.LONG TERM...(SUNDAY NIGHT THROUGH FRIDAY)
ISSUED AT 236 AM MST SAT JAN 5 2013
SUNDAY NIGHT-MONDAY NIGHT...H5 TROUGH WILL SPLIT INTO A NORTHERN AND
SOUTHERN SYSTEM OVER THE WESTERN CONUS WITH GOOD MODEL AGREEMENT
THAT SOUTHERN TROUGH WILL DIVE TO THE SOUTH ALONG THE US/MEXICO
BORDER AND REMAINING WELL TO THE SOUTH OF THE AREA WHILE NORTHERN
TROUGH MOVES ACROSS THE NORTHERN PLAINS. WITH THE EXPECTED TRACK OF
THE UPPER LEVEL SYSTEMS...EXPECT DRY CONDITIONS TO CONTINUE ACROSS
THE AREA WITH NO MEANINGFUL THREAT FOR PRECIPITATION. THESE SYSTEMS
WILL STILL HAVE A SMALL IMPACT ON THE AREA AS SFC TROUGH DEEPENS ON
SUNDAY RESULTING IN SOUTHERLY WINDS INCREASING TO 15 TO 25MPH LATE
SUNDAY AFTERNOON AND REMAIN GUSTY OVERNIGHT. EXPECTING THIS TO HOLD
UP MIN TEMPERATURES SEVERAL DEGREES WITH A FEW AREAS REMAINING ABOVE
NORMAL FOR LOWS.
TUESDAY THROUGH FRIDAY...MODELS HAVE COME INTO BETTER AGREEMENT
WITH THE DEVELOPMENT/TRACK OF THE UPPER LEVEL LOW OVER THE DESERT
SOUTHWEST ON TUESDAY. MODELS HAVE THE CLOSED LOW MOVING OVER
OKLAHOMA AND NORTHERN TEXAS WEDNESDAY NIGHT. AS THE LOW MOVES
NORTH ISENTROPIC LIFT WILL DEVELOP OVER THE SOUTHEAST PART OF THE
AREA...LEADING TO SOME CHANCES FOR PRECIPITATION. AS THE CLOSED
LOW MOVES NORTHEAST THURSDAY PRECIPITATION WILL COME TO AN END.
THURSDAY ANOTHER UPPER LEVEL TROUGH WILL MOVE OVER THE
INTER-MOUNTAIN WEST TOWARD THE AREA. AHEAD OF THE UPPER LEVEL
TROUGH A COLD FRONT WILL MOVE INTO THE AREA LATE THURSDAY NIGHT.
PRECIPITATION CHANCES INCREASE BEHIND THE FRONT AS
ISENTROPIC/SYNOPTIC LIFT AND MOISTURE INCREASE. AT THIS TIME WILL
KEEP PRECIPITATION CHANCES AND MOISTURE AMOUNTS ON THE LOW END DUE TO
FAIRLY WEAK LIFT AHEAD OF THE TROUGH.
TEMPERATURES FOR THE PERIOD WILL BE NEAR NORMAL THROUGH THURSDAY.
BELOW NORMAL TEMPERATURES RETURN BEHIND THE COLD FRONT THURSDAY
NIGHT.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON)
ISSUED AT 1053 AM MST SAT JAN 5 2013
VFR CONDITIONS EXPECTED AT BOTH KGLD AND KMCK THROUGH THE TAF
PERIOD. NORTHWEST WINDS WILL OCCASIONALLY GUST TO 20KTS THROUGH
THE AFTERNOON BEHIND A WEAKENING COLD FRONT...DIMINISHING AROUND
SUNSET.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
CO...NONE.
NE...NONE.
&&
$$
SHORT TERM...JRM
LONG TERM...JRM/JTL
AVIATION...024
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
1252 PM EST SAT JAN 5 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 527 AM EST SAT JAN 5 2013
WV LOOP AND 00Z RAOBS INDICATE WNW FLOW ALOFT ON PERIPHERY OF POLAR
VORTEX CENTERED OVER NUNAVUT CANADA ACROSS HUDSON BAY. COLD AIR IS
NEAR BY WITH H85 TEMPS BLO -15C OVER NORTHERN ONTARIO AND SFC TEMPS
BLO ZERO. FAIRLY MILD BY COMPARISON ACROSS UPR LAKES THOUGH AS H85
TEMPS ARE AROUND -1C. SHALLOW COLD AIR HAS ALLOWED SPOTS ALONG WI
BORDER THAT HAVE CLEAR SKIES TO DROP INTO SINGLE DIGITS ABOVE ZERO.
WARMER AIR AT H85 IS SEEN UPSTREAM OVER NORTHERN PLAINS WITH ABR AT
+4C AND MPX AT +2C. MAIN SHORTWAVE UPSTREAM IS CROSSING ALBERTA AND
SASKATCHEWAN THIS MORNING IN THE NORTHERN STREAM. ALSO IS A WAVE OVER
THE SOUTHERN PLAINS IN THE SOUTHERN STREAM. NORTHERN STREAM WAVE IS
WELL AGREED UPON BY MODELS TO SLIDE INTO NORTHERN PLAINS TODAY AND
DIG ACROSS UPPER LAKES LATE TONIGHT INTO SUNDAY MORNING AS H4-H3 JET
STREAK IN POLAR JET STREAM DIGS INTO WEST SIDE OF TROUGH. ASSOCIATED
SFC LOW IS JUST GETTING GOING OVER WESTERN NORTH DAKOTA WITH MSLP OF
1015MB. OUT AHEAD OF THE LOW TODAY...CURIOUS ON HOW WARM TEMPS WILL
GET. RAP HANDLES LOW CLOUDS WELL RIGHT NOW AND IT INDICATES PARTIAL
CLEARING OF CLOUDS OVER WEST THIS MORNING INTO EARLY AFTN...WHILE
CLOUDS HANG IN OVER KEWEEENAW AND ALSO DOWNWIND OF SW FLOW OVER LK
MICHIGAN. MIXING TO 950MB-925MB SUPPORTS HIGHS REACHING INTO THE 30S
AGAIN FOR MOST AREAS. ONLY PRECIP TODAY WOULD BE OVER EAST WHERE SOME
DRIZZLE MAY OCCUR WITH ADDITIONAL MOISTURE PROVIDED BY LK MICHIGAN.
AS TROUGH DEEPENS TONIGHT...SO TO DOES SFC LOW AS IT MOVES ACROSS LK
SUPERIOR/UPR MICHIGAN. BASED ON 1000-900MB THICKNESS
PACKING...EXPECT COLD FRONT TO DROP OVER NORTHWEST PORTION OF CWA
03Z-06Z TONIGHT AND REACH THE FAR EASTERN CWA BTWN 09Z-12Z.
SOUNDINGS FM NAM AND GFS GENERALLY SIMILAR SHOWING LOW-LEVEL
MOISTURE BUILDING UP AOA 800MB AS TROUGH DEEPENS ACROSS AREA.
MARGINALLY COLD INITIALLY EVEN AFTER FROPA WITH MOISTURE BARELY
REACHING -10C ISOTHERM. KEPT MENTION OF DRIZZLE AND/OR FREEZING
DRIZZLE THROUGH EVENING THEN AS TROUGH DEEPENS/MOISTURE DEPTH
INCREASES AND COLD AIR ADVECTION DEVELOPS /H85 TEMPS FALLING TO
AROUND -11C BY 12Z SUNDAY/ EXPECT A PERIOD OF LAKE ENHANCED SNOW
SHOWERS TO FORM. NORTH WINDS IN MOIST LAYER AND AXIS OF H85 THERMAL
TROUGH POINT TO FAR WEST AND NORTH CENTRAL CWA TO SEE MOST SNOW
TONIGHT. SINCE COLD AIR LAGS FARTHER TO THE EAST...KEPT MENTION OF
FREEZING DRIZZLE IN AT ISQ-ERY UNTIL AROUND 09Z.
USED BLEND OF HIGHER RESOLUTION GUIDANCE TO COME UP WITH QPF/SNOW
AMOUNTS FOR TONIGHT. IN GENERAL MOST OF THESE GUIDANCE SETS CAME UP
WITH AN AVERAGE OF 0.20 INCH FOR 6 HR QPF OVER HIGHER TERRAIN OF
WEST AND NORTH CENTRAL. ALSO LEANED ON LOCAL LK EFFECT GUIDANCE TO
MAKE SURE MODEL DERVIED OUTPUT WAS NOT TOO FAR OUT OF LINE. AT THE
MOST WOULD EXPECT 2-3 INCHES OF SNOW TONIGHT FOR FAVORED AREAS NEAR
LK SUPERIOR AND MAINLY LESS THAN 1 INCH OVER REST OF NORTHERN CWA.
DUE TO STRONGER NORTH WINDS IN BLYR...SNOW PROBABLY FALLS OVER SOUTH
CWA AS WELL...BUT ANY ACCUMS WILL BE MINOR. DO EXPECT TO SEE SNOW
ACCUMS REACH OVER MUCH OF GOGEBIC COUNTY...INTO FAR SOUTHERN
PORTIONS OF MARQUETTE COUNTY AND ALSO OVER NORTHERN PORTION OF DELTA
COUNTY DUE TO THOSE STRONGER WINDS. AS TROUGH DEEPENS AND DEEPER
MOISTURE EXPANDS BRIEFLY MAY SEE SNOW BECOME MORE WIDESPREAD...AT
LEAST BRIEFLY...OVER ROUGHLY EAST THIRD OF CWA WELL AFTER 06Z. THIS
COULD BOOST SNOW AMOUNTS EVEN IN NON-TRADITIONAL LK EFFECT AREAS OF
ALGER/SCHOOLCRAFT/LUCE COUNTIES.
WINDS WILL SHIFT ABRUBTLY TO THE NORTH BEHIND THE COLD FRONT. GUSTS
ALONG LK SUPERIOR FROM KEWEENAW PENINSULA TOWARD BIG BAY/MARQUETTE
AND EVENTUALLY MUNISING MAY REACH OVER 30 MPH LATE TONIGHT.
.LONG TERM...(SUNDAY THROUGH FRIDAY)
ISSUED AT 527 AM EST SAT JAN 5 2013
AS ADVERTISED IN LATE DEC...EARLY JAN HAS STARTED ON THE QUIET SIDE
WITH REGARD TO PCPN IN THE UPPER LAKES. IT LOOKS LIKE THAT WILL
CONTINUE THRU THE FIRST HALF OF THE COMING WEEK. AS IN LATE DEC...
SPLIT FLOW PERSISTS...THOUGH THE SRN STREAM IS LESS ACTIVE AND THE
NRN STREAM IS MORE ACTIVE. IN THE NRN STREAM...A TROF CURRENTLY
DOMINATES ERN CANADA DOWNSTREAM OF RIDGING OVER WRN CANADA THAT
EXTENDS N INTO THE ARCTIC. THIS PLACES THE UPPER LAKES UNDER WNW
FLOW. OVER THE NEXT SEVERAL DAYS...THE RIDGE/TROF OVER WRN/ERN
CANADA RESPECTIVELY WILL RELAX WITH POLAR VORTEX SETTLING INTO A
POSITION NW OF HUDSON BAY. THIS WILL BRING A TRANSITION TO ZONAL
FLOW ACROSS SRN CANADA...ALLOWING MILD PACIFIC AIR TO WASH ACROSS
THE CONUS. THUS...TEMPS HERE DURING THE UPCOMING WEEK WILL BE WELL
ABOVE NORMAL FOR JAN. HEADING INTO THE LATTER PORTION OF THE WEEK...
MEDIUM RANGE GUIDANCE HAS BEEN CONSISTENTLY SUGGESTING TROF
AMPLIFICATION OVER THE WRN CONUS AS RIDGE BEGINS TO BUILD THRU THE
NE PACIFIC TOWARD AK. THIS WILL LIKELY BREAK THE RECENT DRY
PATTERN...PERHAPS AS EARLY AS MIDWEEK AS SRN STREAM ENERGY MAY BE
FORCED FAR ENOUGH N TO BRING A SHIELD OF PCPN (QUITE POSSIBLY MOSTLY
RAIN) INTO UPPER MI. FARTHER DOWN THE ROAD...THERE HAVE BEEN AND
CONTINUE TO BE HINTS FROM MEDIUM RANGE GUIDANCE THAT AT LEAST A
PORTION OF MID TO LATE JAN COULD TURN COLD AS WRN TROF SLOWLY SHIFTS
E INTO CNTRL NAMERICA. HOWEVER...THE FORECASTED MJO PHASE FAVORS
WARM WEATHER OVER THE ERN HALF OF THE CONUS DURING THAT PERIOD.
THUS...IT WILL BE INTERESTING TO SEE HOW FAR E THE TROF SHIFTS AND
HOW FAR SE AND E ARCTIC AIR MOVES. IN ANY EVENT...ASSUMING TROF DOES
MAKE SOME EASTWARD PROGRESS...POTENTIAL SHOULD BE THERE FOR AN
ACTIVE WINTER STORM TRACK FOR A TIME FROM THE SRN ROCKIES/SRN PLAINS
E AND NE INTO AREAS FROM THE MISSISSIPPI RIVER VALLEY EASTWARD.
SO...FOR THOSE LOOKING FOR SNOW FOR OUTDOOR ACTIVITIES...THERE MAY
BE A FAVORABLE WINDOW OF OPPORTUNITY DURING THE MIDDLE OF JAN IF
TROF AND COLDER AIR DON`T END UP BEING HELD TO THE W.
AS ALLUDED TO ABOVE...WARM AND MOSTLY DRY WEATHER WILL BE THE RULE
HEADING INTO THE MIDDLE OF THE COMING WEEK. CLIPPER NRN STREAM
SHORTWAVE THAT DIVES INTO THE WRN LAKES TONIGHT WILL BE QUICKLY
EXITING THE AREA SUN. SOLID HEIGHT RISES AND A CRUSHING INVERSION
DOWN TO 3KFT SUGGEST LIGHT LES OCCURRING SUN MORNING WILL END W TO E
DURING THE DAY...ENDING FIRST OVER THE W. THERE WILL BE AN
OPPORTUNITY FOR TEMPS TO PLUMMET SUN EVENING AS SFC RIDGE AND PERIOD
OF LIGHT/CALM WINDS SHIFTS QUICKLY ACROSS THE AREA. MID/HIGH SINGLE
DIGITS SHOULD GENERALLY BE THE RULE IN THE INTERIOR WITH TEMPS
SHOWING SOME RISE OVERNIGHT IN MANY LOCATIONS. LARGE TEMP BUST
POTENTIAL IS PRESENT AS THERE MAY BE ENOUGH TIME FOR TRADITIONAL
COLD SPOTS TO SLIP BLO ZERO.
GIVEN THE NOTABLY BETTER RUN-TO-RUN CONTINUITY OF THE ECMWF OVER THE
LAST SEVERAL RUNS AND GFS TRENDS TOWARD THE ECMWF...WILL LEAN
STRONGLY TOWARD THE ECMWF FOR MUCH OF THE FCST DURING THE COMING
WEEK. ANY PCPN THRU MIDWEEK WILL DEPEND ON HOW CLOSE ANY SHORTWAVES
PASS TO THE AREA IN THE ZONAL FLOW. AT THIS POINT...WITH ZONALLY
ORIENTED JET SHIFTING N OF THE AREA...PCPN CHANCES APPEAR MINIMAL
THRU MIDWEEK AS EASTWARD TRACKING SHORTWAVES SHOULD PASS N OF THE
AREA.
ON MON...TRANSITION TO ZONAL FLOW ACROSS SRN CANADA WILL BE FULLY
UNDERWAY...AND A SHORTWAVE WILL BE MOVING FROM MANITOBA IN THE
MORNING TO NRN ONTARIO IN THE AFTN. WITH LACK OF MOISTURE UNDER
ZONAL FLOW AND TRACK OF WAVE WELL TO THE N...PCPN IS NOT EXPECTED
HERE. IT SHOULD BE BREEZY/WINDY MON AS 55-65KT LOW-LEVEL JET
TRANSLATES ACROSS THE AREA. FORTUNATELY...STABILITY WILL LIMIT
MIXING DEPTH...BUT FAVORABLE TRACK OF PRES FALL MAX ACROSS NRN
ONTARIO JUST N OF LAKE SUPERIOR COULD MAKE FOR A WIND ADVY EVENT FOR
SOME LOCATIONS. SOUTHERLY WINDS FAVOR ERN ALGER/SCHOOLCRAFT/LUCE FOR
STRONGEST WINDS WITH KERY AND GRAND MARAIS ESPECIALLY FAVORED.
ELSEWHERE...DOWNSLOPE WARMING ALONG LAKE SUPERIOR MAY ENCOURAGE
DEEPER MIXING/STRONGER MOMENTUM TRANSPORT IN THOSE LOCATIONS AS
WELL. SOLID GALES EXPECTED ON LAKE SUPERIOR (GUSTS AT HIGH OBS
PLATFORMS MAY REACH STORM FORCE). GALES ALSO EXPECTED ON NRN LAKE
MI. UNDER BREEZY S/SW WINDS...HIGHS WILL TOP OUT IN THE 30S ACROSS
THE AREA AND COULD NEAR 40F IN LOCATIONS THAT SEE DOWNSLOPING.
WARMTH CONTINUES TUE AS NEXT SHORTWAVE TRACKS ACROSS CNTRL
SASKATCHEWAN TOWARD FAR NRN ONTARIO. IT WILL BE ANOTHER DAY OF WELL
ABOVE NORMAL TEMPS FOR JAN. WHILE MID/HIGH CLOUDS SHOULD KEEP
WARMING IN CHECK...STILL EXPECT HIGHS AGAIN INTO THE 30S.
ANOTHER SHORTWAVE WILL TAKE A TRACK A LITTLE FARTHER S ON WED. WHILE
THAT COULD IMPROVE THE CHC OF A LITTLE PCPN...IT`S NOT WORTHY OF A
MENTION AT THIS POINT GIVEN THE ZONAL PATTERN. WED SHOULD BE ANOTHER
DAY WITH 30S THE RULE FOR HIGH TEMPS.
THE END OF THE WEEK TURNS MORE INTERESTING. AS FLOW BUCKLES WITH WRN
TROF TAKING SHAPE THU/FRI...ATTENTION TURNS TO THE CLOSED SRN STREAM
LOW THAT WILL BE OVER SRN CA SUN AND IN THE VCNTY OF W TX WED.
ALTHOUGH WITH SOME TIMING VARIATION...THE ECMWF HAS BEEN VERY
CONSISTENT SHOWING THIS SYSTEM GETTING KICKED NE THRU THE MID
MISSISSIPPI VALLEY AND INTO THE GREAT LAKES REGION IN RESPONSE TO
THE DEEPENING WRN TROF. LOOKS LIKE PCPN...QUITE POSSIBLY ALL RAIN...
WILL SPREAD INTO UPPER MI THU. COLUMN MAY COOL JUST ENOUGH THU NIGHT
FOR PCPN TO CHANGE TO PREDOMINANTLY SNOW OVER HIGHER TERRAIN. THERE
IS STILL SUFFICIENT UNCERTAINTY IN HOW THIS SRN STREAM SYSTEM WILL
TRACK TO KEEP POPS ONLY IN THE CHC CATEGORY.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON)
ISSUED AT 1251 PM EST SAT JAN 5 2013
ALTHOUGH THE TERMINALS ACROSS UPPER MICHIGAN ARE CURRENLY VFR WITH
MOSTLY CLEAR SKIES...MVFR CIGS HAVE DEVELOPED ACROSS EASTERN UPPER
MICHIGAN DUE TO THE LOWER LEVEL MOISTURE OFF LAKE MICHIGAN. AS THE
SURFACE LOW APPROACHES FROM THE WEST THIS AFTERNOON...EXPECT THESE
CLOUDS TO EXPAND AND SPREAD WEST TO SAW. MEANWHILE...MVFR CIGS
ASSOCIATED WITH THE LOW WILL MOVE INTO CMX AND IWD LATE THIS AFTN
AND EARLY THIS EVENING. LIGHT FREEZING DRIZZLE OR LIGHT SNOW WILL
CHANGE TO ALL SNOW AS THE LOW PASSES ACROSS UPPER MI
OVERNIGHT...STARTING AT IWD AND CMX THIS EVENING...THEN AT SAW AFTER
MIDNIGHT. DUE TO UPSLOPE NORTH FLOW AT IWD AND SAW...EXPECT IFR
CONDITIONS AT THOSE LOCATIONS. IN ADDITION...GUSTY NORTH WINDS WILL
BE A CONCERN WITH SOME BLOWING SNOW POSSIBLE THROUGH SUN MORNING.
IMPROVING CONDITIONS SUN MORNING AS THE LOW DEPARTS AND DRIER AIR
MOVES IN.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 527 AM EST SAT JAN 5 2013
LOW PRESSURE SHIFTING ACROSS THE UPPER GREAT LAKES WILL RESULT IN A
COLD FRONT MOVING ACROSS LAKE SUPERIOR THIS EVENING OVER WESTERN
LAKE SUPERIOR AND BY LATE IN THE NIGHT OVER THE FAR EASTERN PORTION
OF THE LAKE. EXPECT LIGHT EAST-SOUTHEAST WINDS LESS THAN 20 KTS
AHEAD OF THE FRONT TO RAPIDLY INCREASE TO 20-30 KTS FROM THE NORTH
IN THE WAKE OF THE FRONT. GALE FORCE GUSTS ARE NOT OUT OF THE
QUESTION OVER CNTRL LK SUPERIOR AFTER MIDNIGHT DUE TO SHARP PRESSURE
RISES BUILDING IN BRIEFLY BEHIND THE LOW PRESSURE/COLD FRONT.
RIDGE OF HIGH PRES QUICKLY PASSES ACROSS THE UPPER LAKES SUN
EVENING...BRINGING A BRIEF PERIOD OF LIGHT WINDS. THEN...NEXT LOW
PRES SYSTEM TRACKING E INTO NRN ONTARIO MON WILL BRING A SUBSTANTIAL
AND RAPID INCREASE IN S TO SW WINDS ACROSS LAKE SUPERIOR LATE SUN
NIGHT/MON. ALTHOUGH STABILITY OF TEMP PROFILE WILL LIMIT MIXING TO
VERY STRONG WINDS OF 55-65KT AS LOW AS 2-3KFT ABOVE THE LAKE SFC...
FAVORABLE TRACK OF PRES FALL MAX JUST N OF LAKE SUPERIOR WILL BE AN
ENHANCING FACTOR. AT THIS POINT...SOLID MID RANGE GALES ARE EXPECTED
ACROSS THE LAKE MON. HIGH OBS PLATFORMS WILL PROBABLY SEE GUSTS
REACH STORM FORCE. GALES WILL END MON NIGHT AS LOW CONTINUES
EASTWARD AND WINDS VEER SW TO W. BY TUE AFTN...WINDS WILL BE UNDER
20KT.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...JLA
LONG TERM...ROLFSON
AVIATION...MRD
MARINE...JLA/ROLFSON
AREA FORECAST DISCUSSION
NWS DULUTH MN
1200 PM CST SAT JAN 5 2013
.AVIATION.../18Z TAF ISSUANCE/
SKY COVER ACROSS THE NORTHLAND IS HIGHLY VARIABLE AT
MIDDAY...RANGING FROM IFR/LIFR IN THE KBRD AREA TO MVFR OR EVEN
SKC ACROSS THE REGION. THIS WILL CONTINUE TO BE THE CASE THIS
AFTERNOON BUT THINK THE TREND WILL BE TO OVERWHELMINGLY FAVOR MVFR
CIGS AS THE DAY WEARS ON. THE CLOUDS WILL THEN BREAK UP AGAIN
OVERNIGHT AND BECOME MOSTLY CLEAR AGAIN ON SUNDAY MORNING.
&&
.PREV DISCUSSION... /ISSUED 1025 AM CST SAT JAN 5 2013/
UPDATE...
REMOVED MENTION OF PATCHY FOG OVER SERN COUNTIES THIS MORNING AND
EXTENDED FOG MENTION UNTIL NOON ACROSS NRN COUNTIES. MATCHED
CURRENT SATELLITE/OBS TO GRIDS AND APPLIED LATEST HIGH RES/SHORT
RANGE MODELS TO TEMPS/WINDS AND SKIES. NEGLIGIBLE CHANGES MADE TO
FORECAST OVERALL.
PREV DISCUSSION... /ISSUED 535 AM CST SAT JAN 5 2013/
AVIATION...12Z TAFS.
VFR WITH PATCHY MVFR CIGS OVER THE MN ARROWHEAD AND ISOLD LIFR
CIGS/VSBYS IN FZFG AT THE OUTSET. EXPECT MORE CLOUDS TO FORM AS
SFC LOW MOVES INTO MN LATER TODAY. MVFR CIGS ARE ANTICIPATED WITH
SOME -SN OR FLURRIES DEVELOPING AROUND 18Z AS AN UPPER LEVEL TROF
ARRIVES. AFTER 01Z...LOOK FOR AN IMPROVEMENT TO VFR AS THE SFC LOW
DEPARTS AND HIGH PRESSURE MOVES IN.
PREV DISCUSSION... /ISSUED 301 AM CST SAT JAN 5 2013/
SHORT TERM...TODAY THROUGH SUNDAY.
A WEAK SURFACE LOW PRESSURE SYSTEM OVER NORTH DAKOTA WILL SLIDE
EASTWARD OVER NORTHERN MINNESOTA AND NORTHERN WISCONSIN TODAY. THIS
WILL BRING A SLIGHT CHANCE OF LIGHT SNOW THIS AFTERNOON AND EVENING
TO THE NORTHLAND. LITTLE IF ANY SNOW ACCUMULATIONS WILL OCCUR WITH
THIS SYSTEM. THE ONLY EXCEPTION WILL BE THE BAYFIELD PENINSULA AND
GOGEBIC RANGE WHERE LAKE EFFECT SNOWS WILL BEGIN ONCE THE LOW MOVES
TO THE EAST OVER THE EASTERN GREAT LAKES LATE SATURDAY NIGHT. THE
LAKE EFFECT SNOW SHOWERS WILL BEGIN TO TAPER OFF SUNDAY AS HIGH
PRESSURE BUILDS IN FROM THE CENTRAL PLAINS. SNOW ACCUMULATIONS FOR
THE BAYFIELD PENINSULA AND GOGEBIC RANGE WILL BE ONE TO TWO INCHES
WITH MOST OF THAT FALLING BETWEEN 06Z AND 12Z ON SUNDAY. HIGH
TEMPERATURES WILL AVERAGE SLIGHTLY ABOVE NORMAL OVER THE
WEEKEND...MAINLY IN THE LOWER TO MID 20`S.
LONG TERM...SUNDAY NIGHT THROUGH FRIDAY.
A STRONG AREA OF LOW PRESSURE WILL MOVE THROUGH SOUTH CENTRAL CANADA
JUST N OF THE INTERNATIONAL BORDER SUNDAY NIGHT THROUGH MONDAY
NIGHT. DUE TO THE TRACK OF THIS LOW...DO NOT EXPECT ANY SNOW OVER
THE NORTHERN TIER OF THE FA NEXT TO CANADA. WITH THE TIGHTENING
PRESSURE GRADIENT...THE WIND SPEED WILL INCREASE AND BE QUITE BRISK
ON MONDAY. THE WIND SHOULD DIMINISH MONDAY NIGHT HOWEVER AS THE
CANADIAN SFC LOW MOVES QUICKLY TO THE E. HIGH PRESSURE COVERS THE
AREA ON TUESDAY. BY TUESDAY NIGHT...THE MODELS DIVERGE WITH THE NEXT
AREA OF LOW PRESSURE. GFS TAKES THE LOW RIGHT THROUGH THE FA...ECMWF
IS WAY UP IN CANADA...THE GEM BARELY HAS A LOW CENTER SLOWLY MOVING
THROUGH MANITOBA. USED A BLENDED APPROACH WITH SMALL CHANCE POPS
TUESDAY NIGHT AND WEDNESDAY. THE MODELS GROW FARTHER APART WITH TIME
FOR THE REMAINDER OF THE LONG TERM AND USED A BLENDED APPROACH FOR
POPS/WEATHER.
AVIATION...06Z TAFS
MOST OF THE MVFR CEILINGS OVER FAR NORTHEAST MINNESOTA HAVE
DIMINISHED THIS EVENING...WITH MORE OVER FAR NORTH CENTRAL
WISCONSIN/UPPER MICHIGAN. SOME FOG AND IFR CEILINGS HAVE DEVELOPED
AS WELL...AND WE DID ADD VSBY REDUCTIONS AND IFR CEILINGS IN SOME
OF THE TAFS...PARTICULARLY KHIB. WE HAVE YET TO SEE MUCH LOWER
CLOUD DEVELOPMENT LATE THIS EVENING OUTSIDE OF THE SPOTTY IFR
CONDITIONS...AND THE RAP SEEMS TO BE HANDLING CLOUDS BETTER THAN
THE HRRR. AS LOW LEVEL WAA STRENGTHENS OVERNIGHT...WE STILL MAY
SEE SOME DEVELOPMENT LATE EXPANDING INTO SATURDAY. THE LOW IS
STILL FORECAST TO TRACK ACROSS CENTRAL-NORTHERN MINNESOTA
SATURDAY INTO UPPER MICHIGAN BY 00Z SUN. WE KEPT THE TAFS DRY
UNTIL 00Z...THEN IT APPEARS ENOUGH SATURATION WILL OCCUR TO GET
SOME LIGHT SNOW/FLURRIES. MORE SUBSTANTIAL SNOW SHOWERS WILL OCCUR
ALONG THE SOUTH SHORE DUE TO NORTHERLY WINDS FLOWING OVER THE
LAKE.
&&
.POINT TEMPS/POPS...
DLH 23 9 22 11 / 20 20 0 0
INL 17 -4 18 12 / 10 10 0 0
BRD 21 3 20 11 / 20 10 0 0
HYR 24 12 24 11 / 10 30 10 0
ASX 27 17 26 15 / 10 30 10 0
&&
.DLH WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
LS...NONE.
&&
$$
SHORT TERM...TENTINGER
LONG TERM....DAP
AVIATION...DAP
AREA FORECAST DISCUSSION
NWS DULUTH MN
1025 AM CST SAT JAN 5 2013
.UPDATE...
REMOVED MENTION OF PATCHY FOG OVER SERN COUNTIES THIS MORNING AND
EXTENDED FOG MENTION UNTIL NOON ACROSS NRN COUNTIES. MATCHED
CURRENT SATELLITE/OBS TO GRIDS AND APPLIED LATEST HIGH RES/SHORT
RANGE MODELS TO TEMPS/WINDS AND SKIES. NEGLIGIBLE CHANGES MADE TO
FORECAST OVERALL.
&&
.PREV DISCUSSION... /ISSUED 535 AM CST SAT JAN 5 2013/
AVIATION...12Z TAFS.
VFR WITH PATCHY MVFR CIGS OVER THE MN ARROWHEAD AND ISOLD LIFR
CIGS/VSBYS IN FZFG AT THE OUTSET. EXPECT MORE CLOUDS TO FORM AS
SFC LOW MOVES INTO MN LATER TODAY. MVFR CIGS ARE ANTICIPATED WITH
SOME -SN OR FLURRIES DEVELOPING AROUND 18Z AS AN UPPER LEVEL TROF
ARRIVES. AFTER 01Z...LOOK FOR AN IMPROVEMENT TO VFR AS THE SFC LOW
DEPARTS AND HIGH PRESSURE MOVES IN.
PREV DISCUSSION... /ISSUED 301 AM CST SAT JAN 5 2013/
SHORT TERM...TODAY THROUGH SUNDAY.
A WEAK SURFACE LOW PRESSURE SYSTEM OVER NORTH DAKOTA WILL SLIDE
EASTWARD OVER NORTHERN MINNESOTA AND NORTHERN WISCONSIN TODAY. THIS
WILL BRING A SLIGHT CHANCE OF LIGHT SNOW THIS AFTERNOON AND EVENING
TO THE NORTHLAND. LITTLE IF ANY SNOW ACCUMULATIONS WILL OCCUR WITH
THIS SYSTEM. THE ONLY EXCEPTION WILL BE THE BAYFIELD PENINSULA AND
GOGEBIC RANGE WHERE LAKE EFFECT SNOWS WILL BEGIN ONCE THE LOW MOVES
TO THE EAST OVER THE EASTERN GREAT LAKES LATE SATURDAY NIGHT. THE
LAKE EFFECT SNOW SHOWERS WILL BEGIN TO TAPER OFF SUNDAY AS HIGH
PRESSURE BUILDS IN FROM THE CENTRAL PLAINS. SNOW ACCUMULATIONS FOR
THE BAYFIELD PENINSULA AND GOGEBIC RANGE WILL BE ONE TO TWO INCHES
WITH MOST OF THAT FALLING BETWEEN 06Z AND 12Z ON SUNDAY. HIGH
TEMPERATURES WILL AVERAGE SLIGHTLY ABOVE NORMAL OVER THE
WEEKEND...MAINLY IN THE LOWER TO MID 20`S.
LONG TERM...SUNDAY NIGHT THROUGH FRIDAY.
A STRONG AREA OF LOW PRESSURE WILL MOVE THROUGH SOUTH CENTRAL CANADA
JUST N OF THE INTERNATIONAL BORDER SUNDAY NIGHT THROUGH MONDAY
NIGHT. DUE TO THE TRACK OF THIS LOW...DO NOT EXPECT ANY SNOW OVER
THE NORTHERN TIER OF THE FA NEXT TO CANADA. WITH THE TIGHTENING
PRESSURE GRADIENT...THE WIND SPEED WILL INCREASE AND BE QUITE BRISK
ON MONDAY. THE WIND SHOULD DIMINISH MONDAY NIGHT HOWEVER AS THE
CANADIAN SFC LOW MOVES QUICKLY TO THE E. HIGH PRESSURE COVERS THE
AREA ON TUESDAY. BY TUESDAY NIGHT...THE MODELS DIVERGE WITH THE NEXT
AREA OF LOW PRESSURE. GFS TAKES THE LOW RIGHT THROUGH THE FA...ECMWF
IS WAY UP IN CANADA...THE GEM BARELY HAS A LOW CENTER SLOWLY MOVING
THROUGH MANITOBA. USED A BLENDED APPROACH WITH SMALL CHANCE POPS
TUESDAY NIGHT AND WEDNESDAY. THE MODELS GROW FARTHER APART WITH TIME
FOR THE REMAINDER OF THE LONG TERM AND USED A BLENDED APPROACH FOR
POPS/WEATHER.
AVIATION...06Z TAFS
MOST OF THE MVFR CEILINGS OVER FAR NORTHEAST MINNESOTA HAVE
DIMINISHED THIS EVENING...WITH MORE OVER FAR NORTH CENTRAL
WISCONSIN/UPPER MICHIGAN. SOME FOG AND IFR CEILINGS HAVE DEVELOPED
AS WELL...AND WE DID ADD VSBY REDUCTIONS AND IFR CEILINGS IN SOME
OF THE TAFS...PARTICULARLY KHIB. WE HAVE YET TO SEE MUCH LOWER
CLOUD DEVELOPMENT LATE THIS EVENING OUTSIDE OF THE SPOTTY IFR
CONDITIONS...AND THE RAP SEEMS TO BE HANDLING CLOUDS BETTER THAN
THE HRRR. AS LOW LEVEL WAA STRENGTHENS OVERNIGHT...WE STILL MAY
SEE SOME DEVELOPMENT LATE EXPANDING INTO SATURDAY. THE LOW IS
STILL FORECAST TO TRACK ACROSS CENTRAL-NORTHERN MINNESOTA
SATURDAY INTO UPPER MICHIGAN BY 00Z SUN. WE KEPT THE TAFS DRY
UNTIL 00Z...THEN IT APPEARS ENOUGH SATURATION WILL OCCUR TO GET
SOME LIGHT SNOW/FLURRIES. MORE SUBSTANTIAL SNOW SHOWERS WILL OCCUR
ALONG THE SOUTH SHORE DUE TO NORTHERLY WINDS FLOWING OVER THE
LAKE.
&&
.POINT TEMPS/POPS...
DLH 23 9 22 11 / 20 20 0 0
INL 17 -4 18 12 / 10 10 0 0
BRD 21 3 20 11 / 20 10 0 0
HYR 24 12 24 11 / 10 30 10 0
ASX 27 17 26 15 / 10 30 10 0
&&
.DLH WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
LS...NONE.
&&
$$
SHORT TERM...TENTINGER
AREA FORECAST DISCUSSION FOR SOUTHEAST SD/SOUTHWEST MN/NORTHWEST IA
NWS SIOUX FALLS SD
342 PM CST SAT JAN 5 2013
.DISCUSSION.../ISSUED AT 342 PM CST/
UPPER WAVE PUSHING ACROSS THE DAKOTAS THIS AFTERNOON...DRIVING COLD
FRONT INTO THE FAR EASTERN PORTIONS OF THE STATE AT MID AFTERNOON.
CLOUDS PUSHING IN WITH STRONG COLD AIR ADVECTION...AND WITH OFF
SURFACE TEMPS FALLING QUICKLY TOWARD THOSE FAVORING ICE NUCLEATION...
HAVE SEEN FLURRIES DROP IN TO PARTS OF EAST CENTRAL SOUTH DAKOTA.
THE CLOUDS AND FLURRIES WILL CONTINUE TO PUSH EAST AND SOUTHEAST
THIS EVENING...BUT IT IS CERTAINLY A CHALLENGE AS TO HOW QUICKLY TO
BRING IN A MORE PERMANENT CLEARING. RAP AND 18Z NAM ARE NOW IN
FAVOR OF HANGING BACK A PERIOD OF LOWER CLOUDS LATER INTO THE NIGHT
NEAR/WEST OF THE JAMES RIVER AND THEN DRIFTING EAST AS FLOW ALOFT
STARTS TO TURN A BIT MORE WESTERLY. THIS ALSO PRESENTS A LARGE
CHALLENGE TO TEMPERATURES...WHICH WILL PROVE ALMOST IMPOSSIBLE TO
GET CLOSE ON AN HOURLY TIME FRAME WITH IN AND OUT CLOUD TRENDS.
EXPECT A BETTER PUSH OF CLEARING THROUGH THE EASTERN CWA BY LATER
EVENING...BUT ENOUGH WIND OR A FEW MORE CLOUDS LIKELY TO KEEP TEMPS
FROM PLUNGING TOO FAR ANYWHERE. GENERALLY LOOKING FOR QUITE A FEW
SINGLE DIGITS...WITH READINGS AROUND 10 WEST AS WARMER AIR SHUNTS
EAST FAIRLY QUICKLY.
SUNDAY AGAIN PRESENTS A SMALL CHALLENGE TO TEMPS...WITH A VERY
WEAK GRADIENT THROUGH MIDDAY OR EVEN EARLY AFTERNOON IN THE FAR
SOUTHEAST. LOWER ELEVATION LOCATIONS COULD EASILY ONCE AGAIN FIND
THEMSELVES MIRED IN CHILLIER AIR...WITH THE INCREASING SOUTHERLY
GRADIENT MAINLY ACROSS SOUTHEAST SOUTH DAKOTA AND INTO SOUTHWEST
MINNESOTA DURING THE AFTERNOON. HIGH CLOUDS PUSHING ACROSS WOULD
ONLY ENHANCE THE POTENTIAL FOR THIS TO OCCUR...SO WAS CAREFUL TO
NOT WARM CONDITIONS IN THE EAST TOO MUCH...AND DID NUDGE SOME
TEMPERATURES DOWN ACROSS PARTS OF NW IA. THE WEST WILL BE OPEN TO
SOME BETTER WARMING...BUT EVEN THERE THE INVERSION WILL PRESENT A
BIT OF A CHALLENGE TO LOWER ELEVATION WARMING. /CHAPMAN
THE PATTERN OF MILD WEATHER WILL CONTINUE THROUGH MUCH OF THE WEEK
AS A MORE ZONAL PATTERN SETS UP FOR THE FIRST HALF OF THE WORK WEEK.
MILDER WEST TO SOUTHWEST FLOW WILL MAKE TEMPERATURES QUITE TRICKY TO
PINPOINT...PARTICULARLY REGARDING OVERNIGHT LOWS. FOR SUNDAY
NIGHT...BREEZY SOUTH TO SOUTHWEST WINDS WILL LIKELY RESULT IN A
NON-DIURNAL TEMPERATURE TREND WITH LOWS EXPECTED IN THE EVENING OR
SHORTLY AFTER MIDNIGHT...THEN SLOWLY RISING LATE. THE QUESTION IS
HOW COOL WE WILL BE ABLE TO FALL OFF IN THE EVENING. OTHERWISE...
HIGH TEMPERATURES FOR TUESDAY AND WEDNESDAY WILL LIKELY BE NEAR OR
JUST ABOVE FREEZING...WITH THE HIGHS IN THE LOW 40S POSSIBLE IN
SOUTH CENTRAL SD WHERE THE GREATEST POTENTIAL MIXING OF THE MILD LOW
LEVEL TEMPERATURES COULD OCCUR.
LATEST MODEL RUNS SHOWING A LITTLE BETTER AGREEMENT FOR THE SYSTEM
ON WEDNESDAY NIGHT AND THURSDAY...BUT DIVERGE A BIT LEADING INTO
NEXT WEEKEND. ALSO OF NOTE ARE SOME PRETTY BIG CHANGES FROM EARLIER
MODELS RUNS. LATEST 12Z RUNS OF GFS AND ECMWF ARE MUCH SLOWER AND
FURTHER SOUTH WITH THE CLOSED LOW SYSTEM...RESULTING IN LITTLE TO NO
IMPACT ACROSS OUR FORECAST AREA. WENT AHEAD AND REMOVED MENTION OF
POPS FOR WEDNESDAY GIVEN THE SLOWER TIMING. DECIDED TO KEEP MENTION
OF LOW CHANCE POPS MAINLY IN NORTHWEST IOWA ON THURSDAY GIVEN THE
RECENT INCONSISTENCIES BETWEEN MODEL RUNS...BUT DID TRIM BACK
COVERAGE AND QUITE A BIT FROM THE ALL BLEND...WHICH WAS BIASED FROM
THE 00Z ECMWF RUN. TEMPERATURES REMAIN QUITE MILD INTO THURSDAY...
BRINGING THE QUESTION OF PRECIPITATION TYPE IF THIS SYSTEM DOES
GRAZE OUR SOUTHEAST CWA. GIVEN WHAT LOOKS LIKE VERY MILD LOW/MID
LEVELS...PRECIPITATION TYPE MAY BECOME A CONCERN EARLY THURSDAY...
BUT WITH MANY FACTORS UP IN THE AIR...WILL KEEP IT SIMPLE WITH A
RAIN AND SNOW MIX.
THE NEXT AREA OF UNCERTAINTY IS REGARDING A STORM SYSTEM AROUND THE
SATURDAY TIME FRAME. MODELS CONTINUE TO FLIP FLOP WITH
SOLUTIONS...RESULTING IN LARGE TEMPERATURE AND POP DIFFERENCES. NOT
A WHOLE LOT OF CONFIDENCE...ESPECIALLY WITH THE VERY EXTREME GFS
SOLUTION. IT DOES LOOK LIKE A BIT OF A COOL DOWN FRIDAY AND SATURDAY
COMPARED TO EARLIER IN THE WEEK...BUT NOTHING TOO EXTREME. DID NOT
ALTER MUCH FROM THE ALLBLEND.
&&
.AVIATION.../FOR THE 18Z TAF ISSUANCE/
STRATUS FIELD BEHIND ADVANCING COLD FRONT WILL SPREAD INTO KHON IN
THE FIRST HOUR OF NEW TAFS...AND WILL SPREAD THROUGH KFSD AND KSUX
SEQUENTIALLY DURING THE 21Z-23Z WINDOW. CEILINGS ARE EXPECTED TO
MAINLY BE MVFR...BUT VERY LATE AFTERNOON AND EARLY EVENING...SOME
OF THE IFR CEILINGS ALONG WITH MVFR VISIBILITIES IN FLURRIES SHOULD
WANDER SOUTHWARD INTO THE AREA. SIDED WITH THE MORE PESSIMISTIC
DURATION TO CEILINGS IN THE RAP MODEL SOLUTION. WINDS GUSTS WILL
EXCEED 25 KNOTS DURING THE AFTERNOON TO MID EVENING HOURS FOR AREAS
FROM INTERSTATE 29 WESTWARD...AND LATE AFTERNOON AND EVENING FOR
AREAS EAST. /CHAPMAN
&&
.FSD WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
MN...NONE.
IA...NONE.
NE...NONE.
&&
$$
AREA FORECAST DISCUSSION FOR SOUTHEAST SD/SOUTHWEST MN/NORTHWEST IA
NWS SIOUX FALLS SD
1149 AM CST SAT JAN 5 2013
.DISCUSSION.../ISSUED AT 946 AM CST/
WARM FRONT/TROUGH PUSHING TOWARD JAMES VALLEY THIS MORNING...BUT
COLD FRONT CLOSE ON ITS HEELS PUSHING THROUGH NORTHWEST THIRD OF
THE STATE ALREADY BY 15Z. FOR THE MOST PART...GOING FORECAST IS ON
TRACK AND NO SIGNIFICANT CHANGES ARE NEEDED. HAVE ADJUSTED SOME OF
THE HOURLY TEMPERATURE TRENDS TO FIT THE DIFFERENTIAL WARMTH WITH
ELEVATION AHEAD OF WIND SHIFT EARLY THIS MORNING. EXPECT AREAS TO
MIX OUT WITH SHIFT IN WINDS TO WEST AND NORTHWEST...BUT INCREASING
STRATUS AND COLD ADVECTION SHOULD LEAD TO FALLING TEMPS BEHIND THE
BOUNDARY THIS AFTERNOON...AS WELL AS A FEW FLURRIES. DID SLOW UP THE
ADVANCE OF CLOUDS/FLURRIES TO THE SOUTHEAST JUST A BIT. /CHAPMAN
&&
.AVIATION.../FOR THE 18Z TAF ISSUANCE/
STRATUS FIELD BEHIND ADVANCING COLD FRONT WILL SPREAD INTO KHON IN
THE FIRST HOUR OF NEW TAFS...AND WILL SPREAD THROUGH KFSD AND KSUX
SEQUENTIALLY DURING THE 21Z-23Z WINDOW. CEILINGS ARE EXPECTED TO
MAINLY BE MVFR...BUT VERY LATE AFTERNOON AND EARLY EVENING...SOME
OF THE IFR CEILINGS ALONG WITH MVFR VISIBILITIES IN FLURRIES SHOULD
WANDER SOUTHWARD INTO THE AREA. SIDED WITH THE MORE PESSIMISTIC
DURATION TO CEILINGS IN THE RAP MODEL SOLUTION. WINDS GUSTS WILL
EXCEED 25 KNOTS DURING THE AFTERNOON TO MID EVENING HOURS FOR AREAS
FROM INTERSTATE 29 WESTWARD...AND LATE AFTERNOON AND EVENING FOR
AREAS EAST. /CHAPMAN
&&
.PREV DISCUSSION.../ISSUED AT 328 AM CST/
SHORT WAVE WILL DROP SOUTHEAST ACROSS CWA TODAY AND WILL PUSH
COLD FRONT SOUTHEAST ACROSS CWA. WILL MIX OUT WELL BEHIND THIS FRONT
WITH THE COLD AIR ADVECTION...BUT STILL WILL SEE HIGHS NEAR NORMAL.
THIS WAVE WILL BRING A CHANCE OF FLURRIES TO NORTHEAST HALF OF CWA
THIS AFTERNOON AS IT SLIDES SOUTHEAST INTO MINNESOTA. WILL ALSO SEE
GUSTY WIND OF 20 TO 30 MPH BEHIND FRONT AND MAT PRODUCE SOME BLOWING
SNOW ACROSS NORTHEAST CWA. HOWEVER...SNOW COVER NOT THAT DEEP AND
WITH DITCHES NOT FULL OF SNOW...DO NOT SEE MUCH OF A PROBLEM WITH
BLOWING SNOW.
SURFACE RIDGE WILL PUSH EAST ACROSS CWA TONIGHT...AND WITH CLEARING
SKIES AND DECREASING WINDS...WILL SEE LOWS DIP INTO THE SINGLE
DIGITS.
WARM AIR WILL BEGIN TO RETURN TO CWA ON SUNDAY AS RIDGE AXIS ALOFT
SHIFTS TO THE EAST. THIS WILL ALLOW THE BEST WARMING ACROSS THE WEST
ON SUNDAY WITH HIGHS BACK INTO THE 30S ACROSS THE SOUTHWEST. SOUTH
TO SOUTHWEST WINDS SUNDAY NIGHT WILL HELP HOLD TEMPERATURES UP
ACROSS THE CWA WITH WINDS GUSTING TO 30 TO 35 MPH ACROSS THE BUFFALO
RIDGE.
THE MILD WEATHER WILL CONTINUE MONDAY THROUGH WEDNESDAY WITH A MILD
WEST TO SOUTHWEST LOW LEVEL FLOW. GFS APPEARS TO BE OVER DOING WAVE
ON TUESDAY AND PREFER THE MORE TAME EC/GEM SOLUTION. EITHER
WAY...ABOVE NORMAL TEMPERATURES EXPECTED. HOWEVER...SNOW
COVER...ESPECIALLY NORTH OF INTERSTATE 90 WILL HOLD TEMPERATURES
DOWN A BIT...BUT SHOULD STILL MIX OUT INTO LOWER 30S...WITH LOWER
40S ACROSS SOUTHWEST CWA BY TUESDAY AND WEDNESDAY. SNOW COVER ACROSS
NEBRASKA WILL ALSO HAVE SOME IMPACT ACROSS SOUTHWEST CWA. OTHERWISE
IF THERE WAS NO SNOW COVER THERE...COULD HIT THE LOWER 50S.
MODELS DIVERGE A BIT FOR LATE WEDNESDAY NIGHT AND THURSDAY WITH WAVE
LIFTING NORTHEAST OUT OF SOUTHERN PLAINS. GFS MUCH FASTER AND
FURTHER SOUTHEAST...WHILE ECMWF AND GEM SLOWER AND FURTHER NORTH.
GFS HAS NOT HANDLED SOUTHERN SYSTEMS VERY WELL THIS WINTER AND
PREFER MORE STABLE ECMWF. STILL...THIS SYSTEM APPEARS THAT IT WILL
GRAZE THE SOUTHEAST CWA EVEN WITH ITS FURTHEST NORTH SOLUTION. WILL
BE A RELATIVELY WARM SYSTEM AND COULD SEE A MIX OF LIGHT FREEZING
RAIN OR SNOW ACROSS THE FAR SOUTHEAST LATE WEDNESDAY NIGHT. WILL
KEEP THE 20% TO 30% POPS GOING ACROSS THE SOUTHEAST ON THURSDAY.
COLDER AIR WILL FILTER BACK INTO CWA FOR FRIDAY BEHIND THIS SYSTEM.
MODELS ALL OVER THE PLACE FOR NEXT WEEKEND...WITH THE TYPICAL GFS
STORM CREATING SOLUTIONS AFTER DAY 7. ECMWF MUCH WEAKER AND USUALLY
MORE CORRECT.
&&
.FSD WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
MN...NONE.
IA...NONE.
NE...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
201 PM CST SAT JAN 5 2013
.SHORT TERM...THROUGH MONDAY NIGHT
201 PM CST SAT JAN 5 2013
MAIN FORECAST CONCERN IS WITH THE PRECIPITATION CHANCES TONIGHT.
SURFACE ANALYSIS EARLY THIS AFTERNOON SHOWS AN AREA OF LOW
PRESSURE OVER NORTHEAST MINNESOTA NEAR KDLH WITH A COLD FRONT
EXTENDING SOUTHWEST INTO KANSAS.
WATER VAPOR SATELLITE SHOWING THREE SYSTEMS THAT WILL IMPACT THE
REGION TONIGHT. UPPER LEVEL LOW AND SHORT WAVE TROUGH MOVING
ACROSS NORTHERN MISSOURI WILL CONTINUE TO MOVE OFF TO THE
EAST/NORTHEAST TONIGHT TOWARD LAKE ERIE. AS IT DOES...A SHORT WAVE
TROUGH OVER SOUTH DAKOTA WILL MOVE SOUTHEAST ACROSS IOWA INTO THE
OHIO RIVER VALLEY. THIS WAVE WILL RAPIDLY PUSH THE SURFACE LOW AND
COLD FRONT ACROSS THE REGION THROUGH THE REMAINDER OF THE
AFTERNOON AND THIS EVENING. THE THIRD SHORT WAVE TROUGH IS MOVING
INTO NORTH DAKOTA FROM MANITOBA AND IS EXPECTED TO MOVE RIGHT
TOWARD THE AREA THROUGH THE NIGHT. THE FIRST SYSTEM IS EXPECTED TO
PASS BY FAR ENOUGH TO THE SOUTH TO NOT HAVE AN IMPACT ON THE AREA.
HOWEVER...THE SECOND SHORT WAVE TROUGH AND SURFACE SYSTEM MAY HAVE
ENOUGH GOING TO POSSIBLY PRODUCE SOME LIGHT FREEZING DRIZZLE ALONG
AND AHEAD OF THE COLD FRONT. THE 05.12Z NAM SHOWS SOME WEAK
OMEGA...ON THE ORDER OF ABOUT 1 UBAR/S...IN THE 0-2 KM LAYER WHERE
SOME WARM AIR ADVECTION WILL BE OCCURRING IN THE SOUTHWEST FLOW
AHEAD OF THE COLD FRONT. THE NAM AND 05.16Z RAP BUFKIT SOUNDINGS
SHOW THE LOW LEVELS SATURATING UP TO BETWEEN 2 AND 3 KM BEFORE THE
FRONT COMES THROUGH. HOWEVER...SOMEWHAT CONCERNED THAT THE BEST
LIFT MAY BE NEAR THE TOP OR JUST ABOVE THE SATURATED LAYER AND
THUS MAY NOT BE ABLE TO PRODUCE A WHOLE LOT OF DRIZZLE. STILL
ENOUGH OF A CONCERN TO KEEP THE LOW CHANCES FOR THE FREEZING
DRIZZLE AND NO CHANGES ARE PLANNED TO THE CURRENT FORECAST.
THE THIRD SHORT WAVE TROUGH IS PRODUCING SOME REPORTS OF LIGHT
SNOW ACROSS NORTH DAKOTA AND SOUTHERN MANITOBA WITH MVFR
VISIBILITIES. HOWEVER...THESE REPORTS ARE VERY SPORADIC WITH NOT
MUCH AREAL COVERAGE. THE FORECAST SOUNDINGS DO NOT SHOW THIS WAVE
PRODUCING MUCH OMEGA TONIGHT AS IT APPROACHES BUT IT SHOULD
PRODUCE UP TO 12 PVU/S OF VORTICITY ADVECTION IN THE 500-300 MB
LAYER. SOMEWHAT CONCERNED THAT THE MODELS MAY BE UNDERDONE WITH
THE AMOUNT OF LIFT THIS WAVE WILL PRODUCE AND THAT IT COULD END UP
PRODUCING A PERIOD OF VERY LIGHT SNOW BUT WILL MAINTAIN THE
FLURRIES AS THERE IS SOME QUESTION AS TO WHETHER THE MID LEVELS
WILL SATURATE ENOUGH TO ALLOW FOR ANYTHING MORE THAN FLURRIES.
AFTER THIS WAVE MOVES BY...QUIET AND WARMER WEATHER WILL SET UP
OVER THE REGION. THE SURFACE HIGH THAT WILL BE OVER THE REGION
SUNDAY WILL MOVE OFF TO THE EAST SUNDAY NIGHT AS A SYSTEM ROLLS
ACROSS SOUTHERN CANADA. THE PRECIPITATION FROM THIS SYSTEM WILL
STAY WELL TO THE NORTH BUT IT WILL HELP DRAW WARMER AIR IN WITH
HIGHS MONDAY EXPECTED TO TOP OUT IN THE LOWER 30S ACROSS THE
ENTIRE AREA.
.LONG TERM...TUESDAY THROUGH SATURDAY
201 PM CST SAT JAN 5 2013
MEDIUM RANGE MODELS HAVE STARTED TO COME INTO BETTER AGREEMENT
WITH THE SYSTEM EXPECTED TO IMPACT THE GREAT LAKES FOR THE LATTER
HALF OF THE WEEK. THE 05.00Z ECMWF HAS REMAINED CONSISTENT WITH
ITS PREVIOUS RUNS ON THE TRACK OF THE SYSTEM WHILE THE 05.12Z GFS
HAS SHIFTED CONSIDERABLY TOWARD THE ECMWF SOLUTION. THE MODELS ARE
NOW VERY SIMILAR IN TIMING BUT THE GFS STILL DOES NOT BRING THE
SYSTEM AS FAR NORTH AS THE ECMWF. BY 11.00Z /FRIDAY EVENING/ THE
ECMWF PLACES THE UPPER LEVEL LOW NEAR THE WISCONSIN-ILLINOIS
BORDER BETWEEN KDBQ AND KRST WHILE THE GFS IS FARTHER SOUTH NEAR
KSTL. THE AGREEMENT THAT WAS IN PLACE HAS BEEN THROWN OUT THE
WINDOW BY THE 05.12Z ECMWF HAS IT HAS COME IN SLOWER AND FARTHER
SOUTH AND IS NOT SIMILAR WITH ITS TRACK TO THE GFS. WITH THE
DISPARITY BETWEEN THE MODELS...THE ONLY CHANGE MADE TO THE MODEL
CONSENSUS GRIDS WAS TO WEDNESDAY NIGHT. WITH THE ECMWF NOW BEING
SLOWER...IT SUGGESTS THE PRECIPITATION WILL NOT MOVE IN UNTIL
THURSDAY...SO WILL NOW GO WITH A DRY WEDNESDAY NIGHT. THE
PRECIPITATION FROM THIS SYSTEM SHOULD START TO MOVE OUT THURSDAY
NIGHT OR FRIDAY BUT WILL QUICKLY BE FOLLOWED BY THE NEXT SYSTEM.
THE MODELS MAINTAIN A SOUTHWEST FLOW ALOFT BEHIND THIS SYSTEM AND
QUICKLY EJECT OUT ANOTHER SYSTEM FROM THE SOUTHERN ROCKIES. THE
ECMWF IS QUICKER AND FARTHER NORTH THAN THE GFS IN THE UPPER
LEVELS...BUT THE SURFACE TRACKS LOOK TO BE SIMILAR GOING FROM NEAR
KMCI TOWARD KMKE EITHER SATURDAY OR SATURDAY NIGHT. THE ECMWF
SUGGESTS THE FIRST SYSTEM WILL BRING ENOUGH WARM AIR NORTH TO
PRODUCE PRIMARILY RAIN OR A RAIN/SNOW MIX. HOWEVER...THE
BAROCLINIC ZONE LEFT BEHIND MAY BE JUST TO THE SOUTHEAST GIVING
THE SECOND SYSTEM ENOUGH COLD AIR TO WORK WITH TO PRODUCE MAINLY
SNOW.
&&
.AVIATION...THROUGH 18Z SUNDAY
1111 AM CST SAT JAN 5 2013
LOW PRESSURE OVER SOUTH-CENTRAL MN LATE THIS MORNING WILL CONTINUE
TO MOVE EAST ACROSS THE AREA THIS AFTERNOON AND EXIT BY THIS
EVENING. WARMING/PARTIAL MELTING OF THE SNOW PACK TO OUR SOUTH AND
SOUTHWEST WINDS AHEAD OF THE LOW WILL DRAW INCREASINGLY MOIST AIR
INTO THE AREA FOR THE DEVELOPMENT OF STRATUS AFTER 21Z. LOOKING
FOR THIS STRATUS TO BECOME MORE ENTRENCHED OVER THE AREA GOING
INTO THIS EVENING AS COOLER NORTHWEST FLOW BEHIND THE LOW COOLS THE
LOWER BOUNDARY LAYER TO ITS SATURATION POINT. WILL ALSO BE ON THE
LOOKOUT FOR SOME PATCHY FREEZING DRIZZLE/SNOW GRAINS WITH WEAK LIFT
THROUGH THE STRATUS...BUT IT APPEARS THE MAJORITY OF THIS SHOULD
OCCUR EAST OF THE KRST/KLSE TAF SITES WHERE BETTER LOWER LEVEL
MOISTURE CONVERGENCE WILL BE REALIZED. WENT WITH MVFR STRATUS AT
KLSE THIS EVENING/OVERNIGHT WHILE IFR STRATUS WILL BE MORE LIKELY
AT KRST. LOOK FOR THE STRATUS TO CLEAR KRST BY 13Z AND KLSE AROUND
14Z AS DRIER AIR ADVECTS IN FROM THE NORTHERN PLAINS.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
201 PM CST SAT JAN 5 2013
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...04
LONG TERM...04
AVIATION...DAS