Forecast Discussions mentioning any of
"HRRR" "RAP" "RR" "RUC13" "RUC" received at GSD on 12/29/13
AREA FORECAST DISCUSSION
NWS RENO NV
211 PM PST FRI DEC 27 2013
.SYNOPSIS...
AREAS OF FOG AND LOW CLOUDS WILL PERSIST TONIGHT IN SOME LOWER
ELEVATION VALLEYS. OTHERWISE WEAK LOW PRESSURE WILL JUST BRING HIGH
CLOUDS THROUGH SATURDAY. WINDS MAY KICK UP ENOUGH TO MIX OUT SOME
VALLEY INVERSIONS SATURDAY, AND GUSTY NORTHEAST WINDS ARE LIKELY IN
THE SIERRA SATURDAY NIGHT. HIGH PRESSURE WILL BUILD BACK INTO THE
REGION NEXT WEEK WITH NO BIG STORMS ON THE HORIZON.
&&
.SHORT TERM...
FOG AND LOW CLOUDS HAVE PERSISTED EAST OF SUSANVILLE AND NEAR
FALLON/LOVELOCK TODAY. HRRR GUIDANCE, WHICH PICKED UP ON FOG NEAR
FALLON, SUGGESTS IT WILL CONTINUE INTO THE EVENING HOURS IN THE NFL
AND CARSON SINK AREAS. HOWEVER FORECAST SOUNDINGS SHOW DRY AIR
MIXING INTO THE LOW LEVELS WHICH ALONG WITH SLIGHTLY INCREASED WINDS
MAY BE ENOUGH TO ERODE FOG/STRATUS. ADMITTEDLY FORECAST
CONFIDENCE IN FOG TRENDS IS ONLY MEDIUM - IT`S ALWAYS A TRICKY
THING TO FORECAST. BASED ON RECENT IMPROVING TRENDS IN VISIBILITY
AT LOL/NFL I`LL CANCEL THE FREEZING FOG ADVISORY, BUT IT IS NOT
OUT OF THE QUESTION WE MAY NEED TO REISSUE LATER THIS EVENING.
ELSEWHERE PATCHY FOG AND LOW CLOUDS ARE POSSIBLE, BUT REDEVELOPMENT
WILL BE LIMITED BY HIGH CLOUDS AHEAD OF APPROACHING SHORTWAVE. THAT
WAVE MAY KICK UP THE WINDS ENOUGH TO MIX OUT INVERSIONS IN ALL BUT
THE LOWEST VALLEYS ON SATURDAY. BEHIND THE WAVE, FLOW ALOFT TURNS NE
AND STRENGTHENS, LEADING TO A PERIOD OF GUSTY WINDS IN THE SIERRA
SATURDAY NIGHT. RIDGE BUILDS BACK IN STARTING SUNDAY, PROBABLY
LEADING TO MORE INVERSIONS AND HAZY CONDITIONS FOR THE VALLEYS EARLY
NEXT WEEK. GFS SHOWS LIGHT PRECIP ALONG THE NV/OR BORDER ASSOCIATED
WITH A PASSING JET STREAK MONDAY NIGHT. CONFIDENCE IN WHETHER THIS
PRECIP WILL IMPACT OUR CWA IS LOW, SO HAVE CONTINUED DRY FORECAST. CS
&&
.LONG TERM...TUESDAY THROUGH FRIDAY...
DRY PATTERN WITH LIGHT WINDS AND INVERSION CONDITIONS IS EXPECTED TO
PREVAIL THROUGH NEXT FRIDAY. THE LATEST GFS SHOWS THE RIDGE IN
CLOSER PROXIMITY TO WESTERN NV WHICH WOULD RESULT IN REDUCED
COVERAGE OF CIRRUS ESPECIALLY FOR THURS-FRI. THE ECMWF IS A LITTLE
FLATTER WITH THE RIDGE AND SPREADS HIGH LEVEL MOISTURE OVER THE
REGION AT TIMES, ESPECIALLY NORTH OF I-80. THE ECMWF ALSO BRUSHES A
WEAK SHORTWAVE ACROSS THE FAR NORTH BY NEXT FRIDAY EVENING, BUT
THESE FEATURES HAVE VARIED IN TIMING AND LOCATION WITH EACH RUN SO
WILL NOT ADD ANY PRECIP AT THIS TIME. MAX TEMPS SHOULD REMAIN NEAR
50 DEGREES THRU MOST OF NEXT WEEK. THE INVERSION APPEARS WEAKER ON
TUESDAY SO LOWER ELEVATIONS MAY BE A FEW DEGREES WARMER, OTHERWISE
LITTLE VARIATION IS EXPECTED WITH DAYTIME HIGHS BETWEEN WESTERN NV
AND THE SIERRA VALLEYS. MIN TEMPS WILL BE NEAR SEASONAL NORMALS
MAINLY IN THE LOWER-MID 20S FOR URBAN AREAS, AND TEENS FOR THE
TYPICALLY COOLER VALLEYS IN WESTERN NV AND NEAR THE SIERRA.
FOR THE FOLLOWING WEEK, THE GFS AND SOME OF ITS ENSEMBLE MEMBERS
ATTEMPT TO BREAK DOWN THE PERSISTENT RIDGE NEAR THE WEST COAST,
WITH A FEED OF PACIFIC MOISTURE REACHING THE SIERRA ROUGHLY BETWEEN
JANUARY 7 AND 11. SINCE THESE PROJECTIONS ARE SO FAR INTO THE FUTURE
AND THE ECMWF DOES NOT YET RUN INTO THIS TIME FRAME, THE CONFIDENCE
IN SEEING A CHANGE TO A WETTER PATTERN FOR EASTERN CA-WESTERN NV IS
STILL LOW. MJD
&&
.AVIATION...
AT THE MAIN TERMINALS, VFR CONDITIONS WILL PREVAIL THROUGH THIS
WEEKEND AS THE SHORTWAVE PASSAGE TONIGHT SHOULD PREVENT
REDEVELOPMENT OF FREEZING FOG. WINDS WILL GENERALLY REMAIN 10 KT OR
LESS.
A FEW STUBBORN AREAS OF LOW CLOUDS AND FZFG PRODUCING IFR/LIFR CIGS
AND/OR VSBY WILL BE SLOW TO DISSIPATE TONIGHT IN EASTERN LASSEN
COUNTY AFFECTING KSVE, EXTENDING EASTWARD ACROSS THE SMOKE CREEK
DESERT TO NEAR GERLACH. ALSO IMPACTED WILL BE THE WEST CENTRAL NV
BASIN INCLUDING KLOL AND KNFL. SOME LOCATIONS, ESPECIALLY IN
CHURCHILL COUNTY, MAY NOT CLEAR OUT UNTIL MIDDAY SATURDAY. MJD
&&
.REV WATCHES/WARNINGS/ADVISORIES...
NV...NONE.
CA...NONE.
&&
$$
FOR MORE INFORMATION FROM THE NATIONAL WEATHER SERVICE VISIT...
HTTP://WEATHER.GOV/RENO (ALL LOWER CASE)
AREA FORECAST DISCUSSION
NWS DENVER/BOULDER CO
954 AM MST FRI DEC 27 2013
.UPDATE...
&&
.SHORT TERM...CURRENT FORECASTS LOOK REASONABLE. UPPER RIDGE
BUILDING ACROSS GREAT BASIN INTO COLORADO. SOME MID AND HIGH LEVEL
MOISTURE OVER COLORADO AS VERY WEAK MID LEVEL WAVE MOVES INTO
CENTRAL PLAINS. TEMPERATURES WARMING NICELY AS MOST AREAS ACROSS
PLAINS IN THE 40S HEADING TO THE MIDDLE 50S. FLOW ALOFT BECOMES
WESTERLY TONIGHT AHEAD OF APPROACHING TROUGH. WINDS TO INCREASE
ACROSS MOUNTAINS AND FOOTHILLS...PERHAPS SOME GUSTS TO 40 MPH.
.AVIATION...CURRENT TAF TRENDS LOOK REASONABLE. LATEST RAP AND
HRRR SHOW WINDS SHIFTING TO THE NORTH BY 18Z...THEN CLOCKWISE TO
THE SOUTHEAST THROUGH THE AFTERNOON. BASED ON CURRENT WIND AND
PRESSURE PATTERN ACROSS THE AREA...WOULD EXPECT WINDS TO STAY
SOUTHERLY THROUGH THE DAY. DRAINAGE TO THEN DEVELOP DURING THE
EVENING. VFR TO CONTINUE THROUGH SATURDAY. COLD FRONT EXPECTED TO
MOVE ACROSS THE AREA AROUND 19Z WITH GUSTY NORTHERLY WINDS. SOME
INCREASE IN MID AND HIGH LEVEL MOISTURE...WITH LOWER CEILINGS NOT
EXPECTED UNTIL AFTER 00Z.
&&
.PREV DISCUSSION... /ISSUED 328 AM MST FRI DEC 27 2013/
SHORT TERM...WATER VAPOR IMAGERY SHOWING BROAD RIDGE ALOFT
BUILDING ACROSS MUCH OF THE GREAT BASIN WITH RISING HEIGHTS AND
WARMING TEMPERATURES. 700MB TEMPERATURES EXPECTED TO RISE AROUND
+3C TODAY OVER NORTHEAST COLORADO WHICH WILL RESULT IN TEMPERATURES
ABOUT 3-6 DEGREES OF WARMING THIS AFTERNOON. THERE IS SOME HIGH
LEVEL MOISTURE OVER WYOMING WHICH WILL DRIFT OVER NORTHERN
COLORADO THIS MORNING BUT WON`T HAVE MUCH EFFECT ON THE OVERALL
FORECAST. AS THE FLOW ALOFT SHIFTS MORE WESTERLY TONIGHT SHOULD
SEE SOME GUSTY WINDS IN THE 25-40 MPH RANGE INCREASE OVER THE
MOUNTAINS AND EAST SLOPES AFTER MIDNIGHT TONIGHT.
LONG TERM...AN UPPER TROUGH WILL PUSH ITS WAY SOUTHEAST OVER THE
STATE SATURDAY. ITS ASSOCIATED COLD FRONT IS EXPECTED TO MOVE
THROUGH DURING THE DAYTIME SO HIGH TEMPERATURES THAT DAY WILL
LIKELY HAPPEN EARLY ON...ESPECIALLY IN THE NORTH. LIGHT SNOW IS
EXPECTED OVER THE MOUNTAINS DURING THE AFTERNOON...THEN UPSLOPE
FLOW FOLLOWING THE FRONT AND QG VERTICAL LIFT OVERHEAD WILL ALLOW
FOR A CHANCE OF SNOW OVER THE FOOTHILLS AND PLAINS OVERNIGHT. NOT
MUCH QPF EXPECTED WITH THIS SYSTEM...UP TO A COUPLE INCHES OVER
THE MOUNTAINS AND LIKELY LESS THAN A HALF INCH OVER THE PLAINS.
WARMER TEMPERATURES TODAY AND TOMORROW BEFORE THE FRONT WILL
LIKELY HINDER MUCH ACCUMULATION ON THE GROUND OVER THE FOOTHILLS
AND PLAINS. A STRONG PRESSURE GRADIENT ASSOCIATED WITH THE FRONT
WILL BRING NORTH WINDS BEHIND THE FRONT OVER THE EASTERN PLAINS
OF 15 TO 25 MPH SUSTAINED WITH POSSIBLE GUSTS TO 35 MPH.
TEMPERATURES WILL DROP INTO THE TEENS OVERNIGHT OVER THE PLAINS
AND IN THE SINGLE DIGITS OVER THE MOUNTAINS.
SUNDAY`S TEMPERATURES WILL BE 10 TO 20 DEGREES COOLER THAN
SATURDAY WITH 30S OVER THE PLAINS AND 20S FOR THE MOUNTAINS. SNOW
SHOULD BE DONE BY MID MORNING OVER THE PLAINS BUT LIGHT SNOW WILL
CONTINUE OVER THE MOUNTAINS AS A 125+KT JET IN NORTHWEST FLOW
ALOFT MOVES OVERHEAD.
A SHORTWAVE RIDGE WILL MOVE OVERHEAD MONDAY TO BRING WARMER
TEMPERATURES AND A DRY PERIOD FOR THE MOUNTAINS BEFORE THE NEXT
SYSTEM MOVES IN FOR TUESDAY. TEMPERATURES WILL LIKELY BE WARMER
TUESDAY AS THE SYSTEM CREATES DOWNSLOPING OVER THE LEESIDE OF THE
CO ROCKIES. SOME SNOW FOR THE HIGH COUNTRY...BUT LIKELY NOTHING
FOR THE PLAINS EXCEPT PERHAPS FOR THE FAR NORTHEASTERN CORNER.
MOST OF THE COLD AIR WILL BE EXPECTED TO AFFECT CO FOR WEDNESDAY
BUT WILL LIKELY ONLY COOL TEMPERATURES BY A FEW DEGREES. WILL HAVE
TO WATCH TO SEE IF MODELS DIG THIS SYSTEM DEEPER HOWEVER. THE WEST
COAST UPPER RIDGE SHOULD BUILD IN THURSDAY FOR WARMER AND DRIER
WEATHER.
AVIATION...VFR WITH ONLY SCATTERED TO BROKEN CIRRUS CLOUDS FOR
MAINLY THIS MORNING. SOUTH TO SOUTHWEST DRAINAGE WINDS WILL SHIFT
A BIT MORE SOUTHEAST THIS AFTERNOON BUT SPEEDS WILL GENERALLY BE
UNDER 15KT. WITH DECREASING WINDS ALOFT SHOULD BE A SMOOTH FLYING
DAY OVER THE REGION.
&&
.BOU WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...D-L
LONG TERM....KRIEDERMAN
AVIATION...D-L
AREA FORECAST DISCUSSION
NWS TAUNTON MA
1035 AM EST FRI DEC 27 2013
.SYNOPSIS...
HIGH PRESSURE WILL BUILD SOUTH OF NEW ENGLAND INTO THIS WEEKEND
ALLOWING TEMPERATURES TO MODERATE INTO THE EARLY PART OF THE
WEEKEND. A STORM SYSTEM WILL PASS JUST OFFSHORE OF SOUTHEAST NEW
ENGLAND SUNDAY NIGHT BRINGING RAIN ALL AREAS AND A CHANGE TO SNOW
AT NIGHT IN THE INTERIOR. FRIGID ARCTIC AIR WILL INVADE THE
REGION BY TUESDAY WITH BELOW ZERO READINGS POSSIBLE ACROSS
INTERIOR NEW ENGLAND.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
1030 AM UPDATE...
HIGH PRESSURE CENTERED TO THE SOUTHWEST IS PROVIDING DRY WEATHER
FOR SOUTHERN NEW ENGLAND. MADE ADJUSTMENTS TO TEMPS/DEWPOINTS
BASED ON LATEST OBSERVED TRENDS. TWEAKED SKY COVER UP SLIGHTLY
ACROSS THE WESTERN HALF OF SOUTHERN NEW ENGLAND BASED ON VISIBLE
SATELLITE DATA...BUT NO SIGNIFICANT CHANGES TO FORECAST.
PREVIOUS DISCUSSION...
SURFACE HIGH PRESSURE CONTINUING TO BUILD SOUTH AND WEST OVER THE
SOUTHEASTERN CONUS. THIS INVOKES A DRY- SUBSIDENCE INVERSION
ACROSS THE NORTHEAST. EVALUATING UPSTREAM TRENDS...0Z SOUNDINGS
FROM GREEN BAY WI AND DETROIT MI EXHIBIT MOISTURE POOLING BENEATH
THE AFOREMENTIONED INVERSION AS WEAK MID- LEVEL IMPULSES ALLOW FOR
WEAK TROUGHING AND BROAD-SCALE ASCENT.
CONSIDERING MOISTURE FETCH OFF THE LAKES...LIKE THE TRENDS OF THE
LATEST RAP MODEL ANALYSIS THUS GOING WITH HIGH-END PARTLY CLOUDY
CONDITIONS. NOT ENTIRELY CONFIDENT TO GO MOSTLY CLOUDY.
WESTERLY WINDS PREVAIL AND GUSTS UP TO AROUND 20 MPH WILL BE
POSSIBLE...ESPECIALLY OVER THE WATERS. STILL CHILLY WITH HIGHS
AROUND THE LOW- TO MID-30S /LEANED SLIGHTLY COOLER WITH EXPECTED
CLOUDS LATER TODAY/.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH SATURDAY NIGHT/...
TONIGHT...
WITH THE WEAK IMPULSE DURING THE DAY PUSHING EAST OF THE REGION
OVERNIGHT...SURFACE HIGH PRESSURE BUILDS NORTHEAST TOWARDS NOVA
SCOTIA. WESTERLY WINDS DIMINISH WITH RISING HEIGHTS AT THE SURFACE
GRADUALLY TURNING SOUTH-SOUTHWESTERLY INTO THE MORNING. EXPECTING
MOSTLY CLEAR CONDITIONS. LOWS RANGING AROUND THE LOW- TO MID-20S
WITH ONSHORE FLOW.
SATURDAY...
ZONAL FLOW REGIME RESULTS IN A STALLED BOUNDARY ACROSS NORTHERN
NEW ENGLAND ALONG WHICH MID- TO HIGH-LEVEL CLOUDS FILTER. WITH
SURFACE LOW PRESSURE AMPLIFYING OVER THE CENTRAL CONUS COUPLED
WITH MID-LEVEL TROUGHING RESULTS IN THE STALLED BOUNDARY LIFTING
NORTH AS A WARM-FRONT WITH SOUTH-SOUTHWESTERLY FLOW AT THE SURFACE
IN RESPONSE. AGAINST HIGH PRESSURE BUILDING TOWARDS BERMUDA LENDS
TO A BRIEF AMPLIFICATION OF THE FLOW THROUGH THE DAY. GUSTS AROUND
20 MPH /STRONGER OVER THE WATERS WITH SPEEDS UP TO AROUND 30 MPH/
WILL BE POSSIBLE.
WARM-ADVECTION STRONGLY PROCEEDING JUST ABOVE THE SURFACE LENDS TO
A MODERATING TREND IN TEMPERATURES. EXPECT HIGHS ABOVE SEASONABLE
NORMS AROUND THE LOW- TO MID-40S.
SATURDAY NIGHT...
WARM AIRMASS STILL IN PLACE ALOFT WITH SOUTH-SOUTHWESTERLY
ONSHORE FLOW...BUT SHALLOW COLD AIR HOLDS IN PLACE SEEMINGLY
SUSTAINED BY AN AGEOSTROPHIC/ISALLOBARIC COMPONENT OF FLOW OUT OF
THE INTERIOR NORTH-NORTHEAST. WILL GO WITH LOWS AROUND THE MID- TO
UPPER-20S.
WITH THE FRONTAL BOUNDARY NORTH AND LOW PRESSURE ENHANCING OVER
THE SOUTHEASTERN CONUS...EXPECTING SCATTERED TO BROKEN HIGH-LEVEL
CLOUDS ACROSS THE REGION. WILL KEEP THE FORECAST PERIOD DRY.
&&
.LONG TERM /SUNDAY THROUGH THURSDAY/...
BIG PICTURE...UPPER PATTERN FEATURES HUDSON BAY CLOSED LOW WITH
TROUGH AXIS THROUGH THE NORTHERN PLAINS/WESTERN LAKES WHILE AN
OPEN RIDGE SITS ALONG THE PACIFIC COAST. THE LOW SHIFTS EAST
THROUGH QUEBEC MIDWEEK...ONE PIECE OF THE TROUGH AXIS EJECTS
THROUGH NEW ENGLAND MONDAY NIGHT AND THE REMAINDER OF THE AXIS
MOVES THROUGH WEDNESDAY MORNING. THE UPPER JET AXIS REMAINS TO OUR
WEST THROUGH MONDAY MORNING...THEN SHIFTS TO OUR EAST MONDAY
NIGHT. THIS CONTINUES TO SUGGEST MILDER THAN NORMAL TEMPS SUNDAY
WITH A SIGNIFICANT COOLDOWN STARTING MONDAY NIGHT. IF THE AXIS
DOES MOVE THROUGH IN TWO PIECES THEN THAT WOULD SUGGEST A SECOND
BURST OF COLD AIR WEDNESDAY...BUT AT THAT POINT WOULD ANYONE
NOTICE THE DIFFERENCE?
MODELS...THERE IS GENERAL AGREEMENT ON THE PATTERN BUT
DIFFERENCES IN THE DETAILS...ESPECIALLY REGARDING THE COASTAL
STORM ON SUNDAY. THE NAM AND GLOBAL GEM ARE WARMEST/FARTHEST WEST
WITH THE STORM...THE ECMWF AND GFS ARE SIMILAR IN TRACK BUT THE
ECMWF IS FASTER. ALL SUGGEST RAIN FOR MUCH OF OUR AREA...POSSIBLY
SNOW OR A SNOW/RAIN MIX IN SOUTHWEST NH/NW MASS. WE HAVE USED A
BLEND OF MODEL VALUES.
THE DAILIES...
SUNDAY...SHORTWAVE FROM THE GULF OF MEXICO MOVES UP THE
COAST...CROSSING NEW ENGLAND SUNDAY NIGHT/AROUND 06Z MONDAY. COLD
AIR DAMMING SIGNAL AT THE SURFACE IS RATHER MUDDLED WITH SOME
NORTHERLY LOW LEVEL AGEOSTROPIC FLOW BUT NOT AS WELL DEFINED AS IT
IS FARTHER NORTH IN MAINE. PCPN MOVES IN WHILE MILD TEMPS ARE IN
PLACE. CONSENSUS OF STORM TRACKS IS INSIDE THE BENCHMARK BUT
OUTSIDE CAPE COD. MEANWHILE THERMAL FIELDS IN THE VERTICAL ARE
MAINLY AT/ABOVE FREEZING DURING THE AFTERNOON AND EARLY NIGHT. SO
THIS LOOKS LIKE MAINLY A RAIN STORM FOR OUR AREA. TEMPS ARE A
LITTLE COLDER IN SOUTHERN NH AND NORTHCENTRAL/NORTHWEST MASS...AND
COULD SUPPORT A PERIOD OF SNOW AFTER 7 PM. THE STORM PASSES AROUND
1 AM MONDAY AT WHICH POINT WINDS SWING AROUND TO NORTHWEST AND
BRING COLDER AIR SOUTH AS THE PCPN DIMINISHES. COULD BE A PERIOD
OF SNOW MOST AREAS BEFORE THE PCPN ENDS.
TEMP FIELDS ARE A BLEND OF THE LONG RANGE FORECAST DATA. THIS
POINTS TO DAYTIME TEMPS IN THE 40S.
QPF FROM THE STORM LOOKS TO BE IN THE VICINITY OF 1 INCH...WITH
HIGHEST VALUES ON THE CAPE AND ISLANDS. POTENTIAL FOR ACCUMULATING
SNOW WILL BE HIGHEST IN SOUTHERN NH...WHERE SEVERAL INCHES ARE
POSSIBLE. BUT CONFIDENCE FOR SEVERAL INCHES IS LOW AT THIS TIME.
ANOTHER CONCERN WILL BE WITH WIND. BOTH THE ECMWF AND GFS SHOW 1000
MB WINDS AT 30-40 KNOTS OVER THE REGION AS THE STORM PASSES. WITH A
TRACK NEAR NANTUCKET THE BEST WINDS SHOULD FOCUS ON RI AND SOUTHEAST
MASS...BUT IF THE EVENTUAL TRACK IS FARTHER NORTH/WEST THEN THESE
WINDS WOULD EXTEND FARTHER INLAND. THIS MIGHT BRING BORDERLINE WIND
ADVISORY CONDITIONS IN THE SOUTHEAST AND ON THE CAPE/ISLANDS. BASED
ON CURRENT DATA WE SHOULD REMAIN JUST BELOW THE THRESHOLD WITH WIND
GUSTS 30-35 KNOTS.
MONDAY...NORTHWEST WINDS WILL BRING DRIER AIR INTO NEW ENGLAND.
BUT WITH THE UPPER JET JUST MOVING ACROSS...WE WILL BE IN A
TRANSITION DAY. A COLD FRONT MOVES ACROSS THE REGION DURING THE
AFTERNOON. THIS WILL BE A FOCUS FOR AT LEAST SOME CLOUDS. TEMPS
ALOFT WILL CENTER AROUND -10C AND SO SHOULD SUPPORT MAX TEMPS IN
THE 30S AND LOWER 40S.
THE FIRST PHASE OF THE ARCTIC COLD MOVES IN LATE MONDAY AND MONDAY
NIGHT. THIS WILL BRING A CLEARING TREND OVER LAND. DEWPOINTS WILL
DROP THROUGH THE TEENS INTO THE SINGLE NUMBERS. MIN TEMPS ARE A
BLEND OF FORECAST DATA AND RANGE FROM ROUGHLY 5 TO 15. THE FLOW OF
THIS COLD AIR OVER THE WATERS WILL GENERATE OCEAN EFFECT CLOUDS/SNOW
SHOWERS. WITH A NORTHWEST FETCH...THIS SHOULD MAINLY STAY OFFSHORE
ALTHOUGH PROVINCETOWN AND TRURO COULD GET CLIPPED.
TUESDAY THROUGH THURSDAY...ARCTIC COLD IS IN PLACE THROUGH THE
PERIOD. TEMPS ALOFT AT THE TOP OF THE MIXED LAYER WILL BE
EQUIVILENT TO AN 850 MB TEMP OF -18C TO -22C...SO MAX SURFACE
TEMPS SHOULD BE ROUGHLY 15-25F. DEWPOINTS WILL BE IN THE SINGLE
NUMBERS EITHER SIDE OF ZERO...LEAVING ROOM FOR MIN TEMPS IN THE
SINGLE NUMBERS AND POSSIBLY BELOW ZERO.
A SHORTWAVE MOVING THROUGH ON EARLY WEDNESDAY WILL BRING A SECOND
SHORT OF ARCTIC AIR. THIS COULD CAUSE SCATTERED SNOW SHOWERS...BUT
NOT SUFFICIENT CONFIDENCE TO FORECAST THESE SHOWERS.
&&
.AVIATION /16Z FRIDAY THROUGH TUESDAY/...
FORECASTER CONFIDENCE LEVELS...
LOW...LESS THAN 30 PERCENT.
MODERATE...30 TO 60 PERCENT.
HIGH...GREATER THAN 60 PERCENT.
NEAR TERM /THROUGH SATURDAY NIGHT/...HIGH CONFIDENCE.
1030 AM UPDATE...
VFR. WILL SEE SCT-BKN CIGS DEVELOPING ACROSS THE TERMINALS THROUGH
THE DAY NO LOWER THAN LOW-END VFR. PREVAILING WESTERLY WIND FLOW
WITH INFREQUENT GUSTS AROUND 20 KTS. CLOUDS CLEAR OUT OVERNIGHT
AS WINDS DIMINISH AND TURN SOUTHWESTERLY.
MID- TO HIGH-LEVEL CLOUDS BACK ON THE INCREASE SATURDAY INTO
SATURDAY NIGHT WITH SOUTH-SOUTHWESTERLY FLOW. WILL SEE A BRIEF
PERIOD OF STRONG WINDS ON SATURDAY WITH GUSTS AROUND 20 KTS...
STRONGER FOR SOUTH-SOUTHEAST SHORELINE TERMINALS WITH GUSTS UP TO
30 KTS.
KBOS TAF...HIGH CONFIDENCE IN TAF.
KBDL TAF...HIGH CONFIDENCE IN TAF.
OUTLOOK...SUNDAY THROUGH TUESDAY...MODERATE CONFIDENCE
SUNDAY...CIGS AND VSBYS WILL LOWER TO MVFR IN DEVELOPING RAIN AREAS
DURING THE AFTERNOON/EVENING. AREAS OF IFR CIGS/VSBYS IN HEAVIER
RAIN EARLY SUNDAY NIGHT. PRECIPITATION WILL CHANGE TO SNOW IN
SOUTHERN NH EARLY IN THE NIGHT...AND THIS CHANGEOVER MAY SPREAD
SOUTH BEFORE THE PRECIPITATION ENDS AFTER MIDNIGHT. STRONG NORTHEAST
WINDS AT 1000-2000 FEET ABOVE THE GROUND MAY CAUSE LOW LEVEL WIND
SHEAR ESPECIALLY OVER SOUTHEAST MASS AND RI.
MONDAY-TUESDAY...VFR. GUSTY NORTHWEST WINDS MONDAY MAY REACH 25-30
KNOTS. DEVELOPING MVFR CIGS/VSBYS IN OCEAN EFFECT SNOW SHOWERS
OFFSHORE OF THE CAPE AND ISLANDS.
&&
.MARINE...
FORECASTER CONFIDENCE LEVELS...
LOW...LESS THAN 30 PERCENT.
MODERATE...30 TO 60 PERCENT.
HIGH...GREATER THAN 60 PERCENT.
NEAR TERM /THROUGH SATURDAY NIGHT/...HIGH CONFIDENCE.
WESTERLY WINDS WILL REMAIN BRISK TODAY...YET INFREQUENT GUSTS
EXCEEDING 25 KTS. WILL REVERT SMALL-CRAFT HEADLINES TO ADVISORIES
FOR HAZARDOUS SEAS. HEADLINES SHOULD DROP OFF DURING THE EVENING
AS WINDS RELAX AND REVERT OUT OF THE SOUTHWEST ALLOWING SEAS TO
DIMINISH.
SOUTHWEST WINDS WILL BE BRISK ON SATURDAY RESULTING IN SEAS TO
BUILD 7 TO 9 FEET OVER THE SOUTH-SOUTHEAST WATERS WHERE GUSTS UP
TO 30 KTS WILL BE POSSIBLE. WINDS EXPECTED TO RELAX SATURDAY
NIGHT ALLOWING FOR SEAS TO DEAMPLIFY.
OUTLOOK...SUNDAY THROUGH TUESDAY
MODERATE CONFIDENCE
SUNDAY...LOW PRESSURE MOVES UP THE EAST COAST DURING THE DAY AND
PASSES EITHER OVER NANTUCKET OR JUST OFFSHORE AROUND MIDNIGHT SUNDAY
NIGHT. THIS WILL BRING AREAS OF HEAVY RAIN. IT WILL ALSO BRING
STRONG NORTHEAST WINDS...SHIFTING TO NORTHWEST WINDS AFTER MIDNIGHT.
WINDS WILL GUST TO AROUND 30 KNOTS...AND COULD APPROACH 35 KNOTS AT
TIMES. THE STRONG WINDS WILL BUILD SEAS...ESPECIALLY AFTER THE
WINDSHIFT TO NORTHWEST WHEN SEAS ON 8 TO 10 FEET ARE POSSIBLE ON THE
EXPOSED WATERS. A SMALL CRAFT ADVISORY WILL BE NEEDED. A GALE
WARNING IS NOT ANTICIPATED AT THIS TIME...BUT CONDITIONS WILL BE
BORDERLINE.
MONDAY-TUESDAY...SLOWLY DIMINISHING WINDS AND SEAS. NORTHWEST WINDS
ON MONDAY MAY GUST AROUND 30 KNOTS. ARCTIC AIR POURS OVER THE WATERS
LATE MONDAY AND TUESDAY...CAUSING CLOUDS AND OCEAN EFFECT SNOW
SHOWERS ON THE OUTER WATERS. A SMALL CRAFT ADVISORY WILL BE NEEDED
FOR AT LEAST A PART OF THESE TWO DAYS.
&&
.BOX WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
MA...NONE.
NH...NONE.
RI...NONE.
MARINE...SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS UNTIL 3 AM EST
SATURDAY FOR ANZ250-254-255.
SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS UNTIL 10 PM EST THIS
EVENING FOR ANZ256.
&&
$$
SYNOPSIS...SIPPRELL/WTB
NEAR TERM...BELK/SIPPRELL
SHORT TERM...SIPPRELL
LONG TERM...WTB
AVIATION...BELK/SIPPRELL/WTB
MARINE...SIPPRELL/WTB
AREA FORECAST DISCUSSION
NWS TAUNTON MA
625 AM EST FRI DEC 27 2013
.SYNOPSIS...
HIGH PRESSURE WILL BUILD SOUTH OF NEW ENGLAND INTO THIS WEEKEND
ALLOWING TEMPERATURES TO MODERATE INTO THE EARLY PART OF THE
WEEKEND. A STORM SYSTEM WILL PASS JUST OFFSHORE OF SOUTHEAST NEW
ENGLAND SUNDAY NIGHT BRINGING RAIN ALL AREAS AND A CHANGE TO SNOW
AT NIGHT IN THE INTERIOR. FRIGID ARCTIC AIR WILL INVADE THE
REGION BY TUESDAY WITH BELOW ZERO READINGS POSSIBLE ACROSS
INTERIOR NEW ENGLAND.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
630 AM UPDATE...
HIGH PRESSURE CENTERED TO THE SOUTHWEST IS PROVIDING DRY WEATHER
FOR SOUTHERN NEW ENGLAND. MADE ADJUSTMENTS TO TEMPS/DEWPOINTS
BASED ON 6 AM OBS...BUT NO SIGNIFICANT CHANGES TO FORECAST.
PREVIOUS DISCUSSION...
SURFACE HIGH PRESSURE CONTINUING TO BUILD SOUTH AND WEST OVER THE
SOUTHEASTERN CONUS. THIS INVOKES A DRY- SUBSIDENCE INVERSION
ACROSS THE NORTHEAST. EVALUATING UPSTREAM TRENDS...0Z SOUNDINGS
FROM GREEN BAY WI AND DETROIT MI EXHIBIT MOISTURE POOLING BENEATH
THE AFOREMENTIONED INVERSION AS WEAK MID- LEVEL IMPULSES ALLOW FOR
WEAK TROUGHING AND BROAD-SCALE ASCENT.
CONSIDERING MOISTURE FETCH OFF THE LAKES...LIKE THE TRENDS OF THE
LATEST RAP MODEL ANALYSIS THUS GOING WITH HIGH-END PARTLY CLOUDY
CONDITIONS. NOT ENTIRELY CONFIDENT TO GO MOSTLY CLOUDY.
WESTERLY WINDS PREVAIL AND GUSTS UP TO AROUND 20 MPH WILL BE
POSSIBLE...ESPECIALLY OVER THE WATERS. STILL CHILLY WITH HIGHS
AROUND THE LOW- TO MID-30S /LEANED SLIGHTLY COOLER WITH EXPECTED
CLOUDS LATER TODAY/.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH SATURDAY NIGHT/...
TONIGHT...
WITH THE WEAK IMPULSE DURING THE DAY PUSHING EAST OF THE REGION
OVERNIGHT...SURFACE HIGH PRESSURE BUILDS NORTHEAST TOWARDS NOVA
SCOTIA. WESTERLY WINDS DIMINISH WITH RISING HEIGHTS AT THE SURFACE
GRADUALLY TURNING SOUTH-SOUTHWESTERLY INTO THE MORNING. EXPECTING
MOSTLY CLEAR CONDITIONS. LOWS RANGING AROUND THE LOW- TO MID-20S
WITH ONSHORE FLOW.
SATURDAY...
ZONAL FLOW REGIME RESULTS IN A STALLED BOUNDARY ACROSS NORTHERN
NEW ENGLAND ALONG WHICH MID- TO HIGH-LEVEL CLOUDS FILTER. WITH
SURFACE LOW PRESSURE AMPLIFYING OVER THE CENTRAL CONUS COUPLED
WITH MID-LEVEL TROUGHING RESULTS IN THE STALLED BOUNDARY LIFTING
NORTH AS A WARM-FRONT WITH SOUTH-SOUTHWESTERLY FLOW AT THE SURFACE
IN RESPONSE. AGAINST HIGH PRESSURE BUILDING TOWARDS BERMUDA LENDS
TO A BRIEF AMPLIFICATION OF THE FLOW THROUGH THE DAY. GUSTS AROUND
20 MPH /STRONGER OVER THE WATERS WITH SPEEDS UP TO AROUND 30 MPH/
WILL BE POSSIBLE.
WARM-ADVECTION STRONGLY PROCEEDING JUST ABOVE THE SURFACE LENDS TO
A MODERATING TREND IN TEMPERATURES. EXPECT HIGHS ABOVE SEASONABLE
NORMS AROUND THE LOW- TO MID-40S.
SATURDAY NIGHT...
WARM AIRMASS STILL IN PLACE ALOFT WITH SOUTH-SOUTHWESTERLY
ONSHORE FLOW...BUT SHALLOW COLD AIR HOLDS IN PLACE SEEMINGLY
SUSTAINED BY AN AGEOSTROPHIC/ISALLOBARIC COMPONENT OF FLOW OUT OF
THE INTERIOR NORTH-NORTHEAST. WILL GO WITH LOWS AROUND THE MID- TO
UPPER-20S.
WITH THE FRONTAL BOUNDARY NORTH AND LOW PRESSURE ENHANCING OVER
THE SOUTHEASTERN CONUS...EXPECTING SCATTERED TO BROKEN HIGH-LEVEL
CLOUDS ACROSS THE REGION. WILL KEEP THE FORECAST PERIOD DRY.
&&
.LONG TERM /SUNDAY THROUGH THURSDAY/...
BIG PICTURE... UPPER PATTERN FEATURES HUDSON BAY CLOSED LOW WITH
TROUGH AXIS THROUGH THE NORTHERN PLAINS/WESTERN LAKES WHILE AN OPEN
RIDGE SITS ALONG THE PACIFIC COAST. THE LOW SHIFTS EAST THROUGH
QUEBEC MIDWEEK...ONE PIECE OF THE TROUGH AXIS EJECTS THROUGH NEW
ENGLAND MONDAY NIGHT AND THE REMAINDER OF THE AXIS MOVES THROUGH
WEDNESDAY MORNING. THE UPPER JET AXIS REMAINS TO OUR WEST THROUGH
MONDAY MORNING...THEN SHIFTS TO OUR EAST MONDAY NIGHT. THIS
CONTINUES TO SUGGEST MILDER THAN NORMAL TEMPS SUNDAY WITH A
SIGNIFICANT COOLDOWN STARTING MONDAY NIGHT. IF THE AXIS DOES MOVE
THROUGH IN TWO PIECES THEN THAT WOULD SUGGEST A SECOND BURST OF COLD
AIR WEDNESDAY...BUT AT THAT POINT WOULD ANYONE NOTICE THE DIFFERENCE?
MODELS... THERE IS GENERAL AGREEMENT ON THE PATTERN BUT DIFFERENCES
IN THE DETAILS...ESPECIALLY REGARDING THE COASTAL STORM ON SUNDAY.
THE NAM AND GLOBAL GEM ARE WARMEST/FARTHEST WEST WITH THE
STORM...THE ECMWF AND GFS ARE SIMILAR IN TRACK BUT THE ECMWF IS
FASTER. ALL SUGGEST RAIN FOR MUCH OF OUR AREA...POSSIBLY SNOW OR
A SNOW/RAIN MIX IN SOUTHWEST NH/NW MASS. WE HAVE USED A BLEND OF
MODEL VALUES.
THE DAILIES...
SUNDAY... SHORTWAVE FROM THE GULF OF MEXICO MOVES UP THE
COAST...CROSSING NEW ENGLAND SUNDAY NIGHT/AROUND 06Z MONDAY. COLD
AIR DAMMING SIGNAL AT THE SURFACE IS RATHER MUDDLED WITH SOME
NORTHERLY LOW LEVEL AGEOSTROPIC FLOW BUT NOT AS WELL DEFINED AS IT
IS FARTHER NORTH IN MAINE. PCPN MOVES IN WHILE MILD TEMPS ARE IN
PLACE. CONSENSUS OF STORM TRACKS IS INSIDE THE BENCHMARK BUT OUTSIDE
CAPE COD. MEANWHILE THERMAL FIELDS IN THE VERTICAL ARE MAINLY
AT/ABOVE FREEZING DURING THE AFTERNOON AND EARLY NIGHT. SO THIS
LOOKS LIKE MAINLY A RAIN STORM FOR OUR AREA. TEMPS ARE A LITTLE
COLDER IN SOUTHERN NH AND NORTHCENTRAL/NORTHWEST MASS...AND COULD
SUPPORT A PERIOD OF SNOW AFTER 7 PM. THE STORM PASSES AROUND 1 AM
MONDAY AT WHICH POINT WINDS SWING AROUND TO NORTHWEST AND BRING
COLDER AIR SOUTH AS THE PCPN DIMINISHES. COULD BE A PERIOD OF SNOW
MOST AREAS BEFORE THE PCPN ENDS.
TEMP FIELDS ARE A BLEND OF THE LONG RANGE FORECAST DATA. THIS
POINTS TO DAYTIME TEMPS IN THE 40S.
QPF FROM THE STORM LOOKS TO BE IN THE VICINITY OF 1 INCH...WITH
HIGHEST VALUES ON THE CAPE AND ISLANDS. POTENTIAL FOR ACCUMULATING
SNOW WILL BE HIGHEST IN SOUTHERN NH...WHERE SEVERAL INCHES ARE
POSSIBLE. BUT CONFIDENCE FOR SEVERAL INCHES IS LOW AT THIS TIME.
ANOTHER CONCERN WILL BE WITH WIND. BOTH THE ECMWF AND GFS SHOW 1000
MB WINDS AT 30-40 KNOTS OVER THE REGION AS THE STORM PASSES. WITH A
TRACK NEAR NANTUCKET THE BEST WINDS SHOULD FOCUS ON RI AND SOUTHEAST
MASS...BUT IF THE EVENTUAL TRACK IS FARTHER NORTH/WEST THEN THESE
WINDS WOULD EXTEND FARTHER INLAND. THIS MIGHT BRING BORDERLINE WIND
ADVISORY CONDITIONS IN THE SOUTHEAST AND ON THE CAPE/ISLANDS. BASED
ON CURRENT DATA WE SHOULD REMAIN JUST BELOW THE THRESHOLD WITH WIND
GUSTS 30-35 KNOTS.
MONDAY... NORTHWEST WINDS WILL BRING DRIER AIR INTO NEW ENGLAND. BUT
WITH THE UPPER JET JUST MOVING ACROSS...WE WILL BE IN A TRANSITION
DAY. A COLD FRONT MOVES ACROSS THE REGION DURING THE AFTERNOON. THIS
WILL BE A FOCUS FOR AT LEAST SOME CLOUDS. TEMPS ALOFT WILL CENTER
AROUND -10C AND SO SHOULD SUPPORT MAX TEMPS IN THE 30S AND LOWER
40S.
THE FIRST PHASE OF THE ARCTIC COLD MOVES IN LATE MONDAY AND MONDAY
NIGHT. THIS WILL BRING A CLEARING TREND OVER LAND. DEWPOINTS WILL
DROP THROUGH THE TEENS INTO THE SINGLE NUMBERS. MIN TEMPS ARE A
BLEND OF FORECAST DATA AND RANGE FROM ROUGHLY 5 TO 15. THE FLOW OF
THIS COLD AIR OVER THE WATERS WILL GENERATE OCEAN EFFECT CLOUDS/SNOW
SHOWERS. WITH A NORTHWEST FETCH...THIS SHOULD MAINLY STAY OFFSHORE
ALTHOUGH PROVINCETOWN AND TRURO COULD GET CLIPPED.
TUESDAY THROUGH THURSDAY... ARCTIC COLD IS IN PLACE THROUGH THE
PERIOD. TEMPS ALOFT AT THE TOP OF THE MIXED LAYER WILL BE EQUIVILENT
TO AN 850 MB TEMP OF -18C TO -22C...SO MAX SURFACE TEMPS SHOULD BE
ROUGHLY 15-25F. DEWPOINTS WILL BE IN THE SINGLE NUMBERS EITHER SIDE
OF ZERO...LEAVING ROOM FOR MIN TEMPS IN THE SINGLE NUMBERS AND
POSSIBLY BELOW ZERO.
A SHORTWAVE MOVING THROUGH ON EARLY WEDNESDAY WILL BRING A SECOND
SHORT OF ARCTIC AIR. THIS COULD CAUSE SCATTERED SNOW SHOWERS...BUT
NOT SUFFICIENT CONFIDENCE TO FORECAST THESE SHOWERS.
&&
.AVIATION /12Z FRIDAY THROUGH TUESDAY/...
FORECASTER CONFIDENCE LEVELS...
LOW...LESS THAN 30 PERCENT.
MODERATE...30 TO 60 PERCENT.
HIGH...GREATER THAN 60 PERCENT.
NEAR TERM /THROUGH SATURDAY NIGHT/...HIGH CONFIDENCE.
630 AM UPDATE...
VFR. WILL SEE SCT-BKN CIGS DEVELOPING ACROSS THE TERMINALS THROUGH
THE DAY NO LOWER THAN LOW-END VFR. PREVAILING WESTERLY WIND FLOW
WITH INFREQUENT GUSTS AROUND 20 KTS. ACTIVITY CLEARS OUT OVERNIGHT
AS WINDS DIMINISH AND TURN SOUTHWESTERLY.
MID- TO HIGH-LEVEL CLOUDS BACK ON THE INCREASE SATURDAY INTO
SATURDAY NIGHT WITH SOUTH-SOUTHWESTERLY FLOW. WILL SEE A BRIEF
PERIOD OF STRONG WINDS ON SATURDAY WITH GUSTS AROUND 20 KTS...
STRONGER FOR SOUTH-SOUTHEAST SHORELINE TERMINALS WITH GUSTS UP TO
30 KTS.
KBOS TAF...HIGH CONFIDENCE IN TAF.
KBDL TAF...HIGH CONFIDENCE IN TAF.
OUTLOOK...SUNDAY THROUGH TUESDAY... MODERATE CONFIDENCE
SUNDAY...CIGS AND VSBYS WILL LOWER TO MVFR IN DEVELOPING RAIN AREAS
DURING THE AFTERNOON/EVENING. AREAS OF IFR CIGS/VSBYS IN HEAVIER
RAIN EARLY SUNDAY NIGHT. PRECIPITATION WILL CHANGE TO SNOW IN
SOUTHERN NH EARLY IN THE NIGHT...AND THIS CHANGEOVER MAY SPREAD
SOUTH BEFORE THE PRECIPITATION ENDS AFTER MIDNIGHT. STRONG NORTHEAST
WINDS AT 1000-2000 FEET ABOVE THE GROUND MAY CAUSE LOW LEVEL WIND
SHEAR ESPECIALLY OVER SOUTHEAST MASS AND RI.
MONDAY-TUESDAY...VFR. GUSTY NORTHWEST WINDS MONDAY MAY REACH 25-30
KNOTS. DEVELOPING MVFR CIGS/VSBYS IN OCEAN EFFECT SNOW SHOWERS
OFFSHORE OF THE CAPE AND ISLANDS.
&&
.MARINE...
FORECASTER CONFIDENCE LEVELS...
LOW...LESS THAN 30 PERCENT.
MODERATE...30 TO 60 PERCENT.
HIGH...GREATER THAN 60 PERCENT.
NEAR TERM /THROUGH SATURDAY NIGHT/...HIGH CONFIDENCE.
WESTERLY WINDS WILL REMAIN BRISK TODAY...YET INFREQUENT GUSTS
EXCEEDING 25 KTS. WILL REVERT SMALL-CRAFT HEADLINES TO ADVISORIES
FOR HAZARDOUS SEAS. HEADLINES SHOULD DROP OFF DURING THE EVENING
AS WINDS RELAX AND REVERT OUT OF THE SOUTHWEST ALLOWING SEAS TO
DIMINISH.
SOUTHWEST WINDS WILL BE BRISK ON SATURDAY RESULTING IN SEAS TO
BUILD 7 TO 9 FEET OVER THE SOUTH-SOUTHEAST WATERS WHERE GUSTS UP
TO 30 KTS WILL BE POSSIBLE. WINDS EXPECTED TO RELAX SATURDAY
NIGHT ALLOWING FOR SEAS TO DEAMPLIFY.
OUTLOOK...SUNDAY THROUGH TUESDAY
MODERATE CONFIDENCE
SUNDAY...LOW PRESSURE MOVES UP THE EAST COAST DURING THE DAY AND
PASSES EITHER OVER NANTUCKET OR JUST OFFSHORE AROUND MIDNIGHT SUNDAY
NIGHT. THIS WILL BRING AREAS OF HEAVY RAIN. IT WILL ALSO BRING
STRONG NORTHEAST WINDS...SHIFTING TO NORTHWEST WINDS AFTER MIDNIGHT.
WINDS WILL GUST TO AROUND 30 KNOTS...AND COULD APPROACH 35 KNOTS AT
TIMES. THE STRONG WINDS WILL BUILD SEAS...ESPECIALLY AFTER THE
WINDSHIFT TO NORTHWEST WHEN SEAS ON 8 TO 10 FEET ARE POSSIBLE ON THE
EXPOSED WATERS. A SMALL CRAFT ADVISORY WILL BE NEEDED. A GALE
WARNING IS NOT ANTICIPATED AT THIS TIME...BUT CONDITIONS WILL BE
BORDERLINE.
MONDAY-TUESDAY...SLOWLY DIMINISHING WINDS AND SEAS. NORTHWEST WINDS
ON MONDAY MAY GUST AROUND 30 KNOTS. ARCTIC AIR POURS OVER THE WATERS
LATE MONDAY AND TUESDAY...CAUSING CLOUDS AND OCEAN EFFECT SNOW
SHOWERS ON THE OUTER WATERS. A SMALL CRAFT ADVISORY WILL BE NEEDED
FOR AT LEAST A PART OF THESE TWO DAYS.
&&
.BOX WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
MA...NONE.
NH...NONE.
RI...NONE.
MARINE...SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS UNTIL 3 AM EST
SATURDAY FOR ANZ250-254-255.
SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS UNTIL 10 PM EST THIS
EVENING FOR ANZ256.
&&
$$
SYNOPSIS...WTB/SIPPRELL
NEAR TERM...WTB/SIPPRELL
SHORT TERM...SIPPRELL
LONG TERM...WTB
AVIATION...WTB/SIPPRELL
MARINE...WTB/SIPPRELL
AREA FORECAST DISCUSSION
NWS TAUNTON MA
354 AM EST FRI DEC 27 2013
.SYNOPSIS...
HIGH PRESSURE WILL BUILD SOUTH OF NEW ENGLAND INTO THIS WEEKEND
ALLOWING TEMPERATURES TO MODERATE INTO THE EARLY PART OF THE
WEEKEND. A STORM SYSTEM WILL PASS JUST OFFSHORE OF SOUTHEAST NEW
ENGLAND SUNDAY NIGHT BRINGING RAIN ALL AREAS AND A CHANGE TO SNOW
AT NIGHT IN THE INTERIOR. FRIGID ARCTIC AIR WILL INVADE THE
REGION BY TUESDAY WITH BELOW ZERO READINGS POSSIBLE ACROSS
INTERIOR NEW ENGLAND.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
SURFACE HIGH PRESSURE CONTINUING TO BUILD SOUTH AND WEST OVER THE
SOUTHEASTERN CONUS. THIS INVOKES A DRY-SUBSIDENCE INVERSION ACROSS
THE NORTHEAST. EVALUATING UPSTREAM TRENDS...0Z SOUNDINGS FROM
GREEN BAY WI AND DETROIT MI EXHIBIT MOISTURE POOLING BENEATH THE
AFOREMENTIONED INVERSION AS WEAK MID-LEVEL IMPULSES ALLOW FOR
WEAK TROUGHING AND BROAD-SCALE ASCENT.
CONSIDERING MOISTURE FETCH OFF THE LAKES...LIKE THE TRENDS OF THE
LATEST RAP MODEL ANALYSIS THUS GOING WITH HIGH-END PARTLY CLOUDY
CONDITIONS. NOT ENTIRELY CONFIDENT TO GO MOSTLY CLOUDY.
WESTERLY WINDS PREVAIL AND GUSTS UP TO AROUND 20 MPH WILL BE
POSSIBLE...ESPECIALLY OVER THE WATERS. STILL CHILLY WITH HIGHS
AROUND THE LOW- TO MID-30S /LEANED SLIGHTLY COOLER WITH EXPECTED
CLOUDS LATER TODAY/.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH SATURDAY NIGHT/...
TONIGHT...
WITH THE WEAK IMPULSE DURING THE DAY PUSHING EAST OF THE REGION
OVERNIGHT...SURFACE HIGH PRESSURE BUILDS NORTHEAST TOWARDS NOVA
SCOTIA. WESTERLY WINDS DIMINISH WITH RISING HEIGHTS AT THE SURFACE
GRADUALLY TURNING SOUTH-SOUTHWESTERLY INTO THE MORNING. EXPECTING
MOSTLY CLEAR CONDITIONS. LOWS RANGING AROUND THE LOW- TO MID-20S
WITH ONSHORE FLOW.
SATURDAY...
ZONAL FLOW REGIME RESULTS IN A STALLED BOUNDARY ACROSS NORTHERN
NEW ENGLAND ALONG WHICH MID- TO HIGH-LEVEL CLOUDS FILTER. WITH
SURFACE LOW PRESSURE AMPLIFYING OVER THE CENTRAL CONUS COUPLED
WITH MID-LEVEL TROUGHING RESULTS IN THE STALLED BOUNDARY LIFTING
NORTH AS A WARM-FRONT WITH SOUTH-SOUTHWESTERLY FLOW AT THE SURFACE
IN RESPONSE. AGAINST HIGH PRESSURE BUILDING TOWARDS BERMUDA LENDS
TO A BRIEF AMPLIFICATION OF THE FLOW THROUGH THE DAY. GUSTS AROUND
20 MPH /STRONGER OVER THE WATERS WITH SPEEDS UP TO AROUND 30 MPH/
WILL BE POSSIBLE.
WARM-ADVECTION STRONGLY PROCEEDING JUST ABOVE THE SURFACE LENDS TO
A MODERATING TREND IN TEMPERATURES. EXPECT HIGHS ABOVE SEASONABLE
NORMS AROUND THE LOW- TO MID-40S.
SATURDAY NIGHT...
WARM AIRMASS STILL IN PLACE ALOFT WITH SOUTH-SOUTHWESTERLY
ONSHORE FLOW...BUT SHALLOW COLD AIR HOLDS IN PLACE SEEMINGLY
SUSTAINED BY AN AGEOSTROPHIC/ISALLOBARIC COMPONENT OF FLOW OUT OF
THE INTERIOR NORTH-NORTHEAST. WILL GO WITH LOWS AROUND THE MID- TO
UPPER-20S.
WITH THE FRONTAL BOUNDARY NORTH AND LOW PRESSURE ENHANCING OVER
THE SOUTHEASTERN CONUS...EXPECTING SCATTERED TO BROKEN HIGH-LEVEL
CLOUDS ACROSS THE REGION. WILL KEEP THE FORECAST PERIOD DRY.
&&
.LONG TERM /SUNDAY THROUGH THURSDAY/...
BIG PICTURE... UPPER PATTERN FEATURES HUDSON BAY CLOSED LOW WITH
TROUGH AXIS THROUGH THE NORTHERN PLAINS/WESTERN LAKES WHILE AN OPEN
RIDGE SITS ALONG THE PACIFIC COAST. THE LOW SHIFTS EAST THROUGH
QUEBEC MIDWEEK...ONE PIECE OF THE TROUGH AXIS EJECTS THROUGH NEW
ENGLAND MONDAY NIGHT AND THE REMAINDER OF THE AXIS MOVES THROUGH
WEDNESDAY MORNING. THE UPPER JET AXIS REMAINS TO OUR WEST THROUGH
MONDAY MORNING...THEN SHIFTS TO OUR EAST MONDAY NIGHT. THIS
CONTINUES TO SUGGEST MILDER THAN NORMAL TEMPS SUNDAY WITH A
SIGNIFICANT COOLDOWN STARTING MONDAY NIGHT. IF THE AXIS DOES MOVE
THROUGH IN TWO PIECES THEN THAT WOULD SUGGEST A SECOND BURST OF COLD
AIR WEDNESDAY...BUT AT THAT POINT WOULD ANYONE NOTICE THE DIFFERENCE?
MODELS... THERE IS GENERAL AGREEMENT ON THE PATTERN BUT DIFFERENCES
IN THE DETAILS...ESPECIALLY REGARDING THE COASTAL STORM ON SUNDAY.
THE NAM AND GLOBAL GEM ARE WARMEST/FARTHEST WEST WITH THE
STORM...THE ECMWF AND GFS ARE SIMILAR IN TRACK BUT THE ECMWF IS
FASTER. ALL SUGGEST RAIN FOR MUCH OF OUR AREA...POSSIBLY SNOW OR
A SNOW/RAIN MIX IN SOUTHWEST NH/NW MASS. WE HAVE USED A BLEND OF
MODEL VALUES.
THE DAILIES...
SUNDAY... SHORTWAVE FROM THE GULF OF MEXICO MOVES UP THE
COAST...CROSSING NEW ENGLAND SUNDAY NIGHT/AROUND 06Z MONDAY. COLD
AIR DAMMING SIGNAL AT THE SURFACE IS RATHER MUDDLED WITH SOME
NORTHERLY LOW LEVEL AGEOSTROPIC FLOW BUT NOT AS WELL DEFINED AS IT
IS FARTHER NORTH IN MAINE. PCPN MOVES IN WHILE MILD TEMPS ARE IN
PLACE. CONSENSUS OF STORM TRACKS IS INSIDE THE BENCHMARK BUT OUTSIDE
CAPE COD. MEANWHILE THERMAL FIELDS IN THE VERTICAL ARE MAINLY
AT/ABOVE FREEZING DURING THE AFTERNOON AND EARLY NIGHT. SO THIS
LOOKS LIKE MAINLY A RAIN STORM FOR OUR AREA. TEMPS ARE A LITTLE
COLDER IN SOUTHERN NH AND NORTHCENTRAL/NORTHWEST MASS...AND COULD
SUPPORT A PERIOD OF SNOW AFTER 7 PM. THE STORM PASSES AROUND 1 AM
MONDAY AT WHICH POINT WINDS SWING AROUND TO NORTHWEST AND BRING
COLDER AIR SOUTH AS THE PCPN DIMINISHES. COULD BE A PERIOD OF SNOW
MOST AREAS BEFORE THE PCPN ENDS.
TEMP FIELDS ARE A BLEND OF THE LONG RANGE FORECAST DATA. THIS
POINTS TO DAYTIME TEMPS IN THE 40S.
QPF FROM THE STORM LOOKS TO BE IN THE VICINITY OF 1 INCH...WITH
HIGHEST VALUES ON THE CAPE AND ISLANDS. POTENTIAL FOR ACCUMULATING
SNOW WILL BE HIGHEST IN SOUTHERN NH...WHERE SEVERAL INCHES ARE
POSSIBLE. BUT CONFIDENCE FOR SEVERAL INCHES IS LOW AT THIS TIME.
ANOTHER CONCERN WILL BE WITH WIND. BOTH THE ECMWF AND GFS SHOW 1000
MB WINDS AT 30-40 KNOTS OVER THE REGION AS THE STORM PASSES. WITH A
TRACK NEAR NANTUCKET THE BEST WINDS SHOULD FOCUS ON RI AND SOUTHEAST
MASS...BUT IF THE EVENTUAL TRACK IS FARTHER NORTH/WEST THEN THESE
WINDS WOULD EXTEND FARTHER INLAND. THIS MIGHT BRING BORDERLINE WIND
ADVISORY CONDITIONS IN THE SOUTHEAST AND ON THE CAPE/ISLANDS. BASED
ON CURRENT DATA WE SHOULD REMAIN JUST BELOW THE THRESHOLD WITH WIND
GUSTS 30-35 KNOTS.
MONDAY... NORTHWEST WINDS WILL BRING DRIER AIR INTO NEW ENGLAND. BUT
WITH THE UPPER JET JUST MOVING ACROSS...WE WILL BE IN A TRANSITION
DAY. A COLD FRONT MOVES ACROSS THE REGION DURING THE AFTERNOON. THIS
WILL BE A FOCUS FOR AT LEAST SOME CLOUDS. TEMPS ALOFT WILL CENTER
AROUND -10C AND SO SHOULD SUPPORT MAX TEMPS IN THE 30S AND LOWER
40S.
THE FIRST PHASE OF THE ARCTIC COLD MOVES IN LATE MONDAY AND MONDAY
NIGHT. THIS WILL BRING A CLEARING TREND OVER LAND. DEWPOINTS WILL
DROP THROUGH THE TEENS INTO THE SINGLE NUMBERS. MIN TEMPS ARE A
BLEND OF FORECAST DATA AND RANGE FROM ROUGHLY 5 TO 15. THE FLOW OF
THIS COLD AIR OVER THE WATERS WILL GENERATE OCEAN EFFECT CLOUDS/SNOW
SHOWERS. WITH A NORTHWEST FETCH...THIS SHOULD MAINLY STAY OFFSHORE
ALTHOUGH PROVINCETOWN AND TRURO COULD GET CLIPPED.
TUESDAY THROUGH THURSDAY... ARCTIC COLD IS IN PLACE THROUGH THE
PERIOD. TEMPS ALOFT AT THE TOP OF THE MIXED LAYER WILL BE EQUIVILENT
TO AN 850 MB TEMP OF -18C TO -22C...SO MAX SURFACE TEMPS SHOULD BE
ROUGHLY 15-25F. DEWPOINTS WILL BE IN THE SINGLE NUMBERS EITHER SIDE
OF ZERO...LEAVING ROOM FOR MIN TEMPS IN THE SINGLE NUMBERS AND
POSSIBLY BELOW ZERO.
A SHORTWAVE MOVING THROUGH ON EARLY WEDNESDAY WILL BRING A SECOND
SHORT OF ARCTIC AIR. THIS COULD CAUSE SCATTERED SNOW SHOWERS...BUT
NOT SUFFICIENT CONFIDENCE TO FORECAST THESE SHOWERS.
&&
.AVIATION /09Z FRIDAY THROUGH TUESDAY/...
FORECASTER CONFIDENCE LEVELS...
LOW...LESS THAN 30 PERCENT.
MODERATE...30 TO 60 PERCENT.
HIGH...GREATER THAN 60 PERCENT.
NEAR TERM /THROUGH SATURDAY NIGHT/...HIGH CONFIDENCE.
9Z UPDATE...
VFR. WILL SEE SCT-BKN CIGS DEVELOPING ACROSS THE TERMINALS THROUGH
THE DAY NO LOWER THAN LOW-END VFR. PREVAILING WESTERLY WIND FLOW
WITH INFREQUENT GUSTS AROUND 20 KTS. ACTIVITY CLEARS OUT OVERNIGHT
AS WINDS DIMINISH AND TURN SOUTHWESTERLY.
MID- TO HIGH-LEVEL CLOUDS BACK ON THE INCREASE SATURDAY INTO
SATURDAY NIGHT WITH SOUTH-SOUTHWESTERLY FLOW. WILL SEE A BRIEF
PERIOD OF STRONG WINDS ON SATURDAY WITH GUSTS AROUND 20 KTS...
STRONGER FOR SOUTH-SOUTHEAST SHORELINE TERMINALS WITH GUSTS UP TO
30 KTS.
KBOS TAF...HIGH CONFIDENCE IN TAF.
KBDL TAF...HIGH CONFIDENCE IN TAF.
OUTLOOK...SUNDAY THROUGH TUESDAY... MODERATE CONFIDENCE
SUNDAY...CIGS AND VSBYS WILL LOWER TO MVFR IN DEVELOPING RAIN AREAS
DURING THE AFTERNOON/EVENING. AREAS OF IFR CIGS/VSBYS IN HEAVIER
RAIN EARLY SUNDAY NIGHT. PRECIPITATION WILL CHANGE TO SNOW IN
SOUTHERN NH EARLY IN THE NIGHT...AND THIS CHANGEOVER MAY SPREAD
SOUTH BEFORE THE PRECIPITATION ENDS AFTER MIDNIGHT. STRONG NORTHEAST
WINDS AT 1000-2000 FEET ABOVE THE GROUND MAY CAUSE LOW LEVEL WIND
SHEAR ESPECIALLY OVER SOUTHEAST MASS AND RI.
MONDAY-TUESDAY...VFR. GUSTY NORTHWEST WINDS MONDAY MAY REACH 25-30
KNOTS. DEVELOPING MVFR CIGS/VSBYS IN OCEAN EFFECT SNOW SHOWERS
OFFSHORE OF THE CAPE AND ISLANDS.
&&
.MARINE...
FORECASTER CONFIDENCE LEVELS...
LOW...LESS THAN 30 PERCENT.
MODERATE...30 TO 60 PERCENT.
HIGH...GREATER THAN 60 PERCENT.
NEAR TERM /THROUGH SATURDAY NIGHT/...HIGH CONFIDENCE.
WESTERLY WINDS WILL REMAIN BRISK TODAY...YET INFREQUENT GUSTS
EXCEEDING 25 KTS. WILL REVERT SMALL-CRAFT HEADLINES TO ADVISORIES
FOR HAZARDOUS SEAS. HEADLINES SHOULD DROP OFF DURING THE EVENING
AS WINDS RELAX AND REVERT OUT OF THE SOUTHWEST ALLOWING SEAS TO
DIMINISH.
SOUTHWEST WINDS WILL BE BRISK ON SATURDAY RESULTING IN SEAS TO
BUILD 7 TO 9 FEET OVER THE SOUTH-SOUTHEAST WATERS WHERE GUSTS UP
TO 30 KTS WILL BE POSSIBLE. WINDS EXPECTED TO RELAX SATURDAY
NIGHT ALLOWING FOR SEAS TO DEAMPLIFY.
OUTLOOK...SUNDAY THROUGH TUESDAY
MODERATE CONFIDENCE
SUNDAY...LOW PRESSURE MOVES UP THE EAST COAST DURING THE DAY AND
PASSES EITHER OVER NANTUCKET OR JUST OFFSHORE AROUND MIDNIGHT SUNDAY
NIGHT. THIS WILL BRING AREAS OF HEAVY RAIN. IT WILL ALSO BRING
STRONG NORTHEAST WINDS...SHIFTING TO NORTHWEST WINDS AFTER MIDNIGHT.
WINDS WILL GUST TO AROUND 30 KNOTS...AND COULD APPROACH 35 KNOTS AT
TIMES. THE STRONG WINDS WILL BUILD SEAS...ESPECIALLY AFTER THE
WINDSHIFT TO NORTHWEST WHEN SEAS ON 8 TO 10 FEET ARE POSSIBLE ON THE
EXPOSED WATERS. A SMALL CRAFT ADVISORY WILL BE NEEDED. A GALE
WARNING IS NOT ANTICIPATED AT THIS TIME...BUT CONDITIONS WILL BE
BORDERLINE.
MONDAY-TUESDAY...SLOWLY DIMINISHING WINDS AND SEAS. NORTHWEST WINDS
ON MONDAY MAY GUST AROUND 30 KNOTS. ARCTIC AIR POURS OVER THE WATERS
LATE MONDAY AND TUESDAY...CAUSING CLOUDS AND OCEAN EFFECT SNOW
SHOWERS ON THE OUTER WATERS. A SMALL CRAFT ADVISORY WILL BE NEEDED
FOR AT LEAST A PART OF THESE TWO DAYS.
&&
.BOX WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
MA...NONE.
NH...NONE.
RI...NONE.
MARINE...SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS UNTIL 3 AM EST
SATURDAY FOR ANZ250-254-255.
SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS UNTIL 10 PM EST THIS
EVENING FOR ANZ256.
&&
$$
SYNOPSIS...WTB/SIPPRELL
NEAR TERM...SIPPRELL
SHORT TERM...SIPPRELL
LONG TERM...WTB
AVIATION...WTB/SIPPRELL
MARINE...WTB/SIPPRELL
AREA FORECAST DISCUSSION
NWS TAUNTON MA
308 AM EST FRI DEC 27 2013
.SYNOPSIS...
HIGH PRESSURE WILL BUILD SOUTH OF NEW ENGLAND INTO THIS WEEKEND
ALLOWING TEMPERATURES TO MODERATE INTO THE EARLY PART OF THE
WEEKEND. A STORM SYSTEM WILL PASS IN VICINITY OF SOUTHEAST NEW
ENGLAND SUNDAY INTO SUNDAY NIGHT AS MOSTLY RAIN WITH AN INTERIOR
WINTRY MIX. FRIGID ARCTIC AIR WILL INVADE THE REGION BY TUESDAY
WITH BELOW ZERO READINGS POSSIBLE ACROSS INTERIOR NEW ENGLAND.
&&
.NEAR TERM /THROUGH TODAY/...
SURFACE HIGH PRESSURE CONTINUING TO BUILD SOUTH AND WEST OVER THE
SOUTHEASTERN CONUS. THIS INVOKES A DRY-SUBSIDENCE INVERSION ACROSS
THE NORTHEAST. EVALUATING UPSTREAM TRENDS...0Z SOUNDINGS FROM
GREEN BAY WI AND DETROIT MI EXHIBIT MOISTURE POOLING BENEATH THE
AFOREMENTIONED INVERSION AS WEAK MID-LEVEL IMPULSES ALLOW FOR
WEAK TROUGHING AND BROAD-SCALE ASCENT.
CONSIDERING MOISTURE FETCH OFF THE LAKES...LIKE THE TRENDS OF THE
LATEST RAP MODEL ANALYSIS THUS GOING WITH HIGH-END PARTLY CLOUDY
CONDITIONS. NOT ENTIRELY CONFIDENT TO GO MOSTLY CLOUDY.
WESTERLY WINDS PREVAIL AND GUSTS UP TO AROUND 20 MPH WILL BE
POSSIBLE...ESPECIALLY OVER THE WATERS. STILL CHILLY WITH HIGHS
AROUND THE LOW- TO MID-30S /LEANED SLIGHTLY COOLER WITH EXPECTED
CLOUDS LATER TODAY/.
&&
.SHORT TERM /TONIGHT THROUGH SATURDAY NIGHT/...
TONIGHT...
WITH THE WEAK IMPULSE DURING THE DAY PUSHING EAST OF THE REGION
OVERNIGHT...SURFACE HIGH PRESSURE BUILDS NORTHEAST TOWARDS NOVA
SCOTIA. WESTERLY WINDS DIMINISH WITH RISING HEIGHTS AT THE SURFACE
GRADUALLY TURNING SOUTH-SOUTHWESTERLY INTO THE MORNING. EXPECTING
MOSTLY CLEAR CONDITIONS. LOWS RANGING AROUND THE LOW- TO MID-20S
WITH ONSHORE FLOW.
SATURDAY...
ZONAL FLOW REGIME RESULTS IN A STALLED BOUNDARY ACROSS NORTHERN
NEW ENGLAND ALONG WHICH MID- TO HIGH-LEVEL CLOUDS FILTER. WITH
SURFACE LOW PRESSURE AMPLIFYING OVER THE CENTRAL CONUS COUPLED
WITH MID-LEVEL TROUGHING RESULTS IN THE STALLED BOUNDARY LIFTING
NORTH AS A WARM-FRONT WITH SOUTH-SOUTHWESTERLY FLOW AT THE SURFACE
IN RESPONSE. AGAINST HIGH PRESSURE BUILDING TOWARDS BERMUDA LENDS
TO A BRIEF AMPLIFICATION OF THE FLOW THROUGH THE DAY. GUSTS AROUND
20 MPH /STRONGER OVER THE WATERS WITH SPEEDS UP TO AROUND 30 MPH/
WILL BE POSSIBLE.
WARM-ADVECTION STRONGLY PROCEEDING JUST ABOVE THE SURFACE LENDS TO
A MODERATING TREND IN TEMPERATURES. EXPECT HIGHS ABOVE SEASONABLE
NORMS AROUND THE LOW- TO MID-40S.
SATURDAY NIGHT...
WARM AIRMASS STILL IN PLACE ALOFT WITH SOUTH-SOUTHWESTERLY
ONSHORE FLOW...BUT SHALLOW COLD AIR HOLDS IN PLACE SEEMINGLY
SUSTAINED BY AN AGEOSTROPHIC/ISALLOBARIC COMPONENT OF FLOW OUT OF
THE INTERIOR NORTH-NORTHEAST. WILL GO WITH LOWS AROUND THE MID- TO
UPPER-20S.
WITH THE FRONTAL BOUNDARY NORTH AND LOW PRESSURE ENHANCING OVER
THE SOUTHEASTERN CONUS...EXPECTING SCATTERED TO BROKEN HIGH-LEVEL
CLOUDS ACROSS THE REGION. WILL KEEP THE FORECAST PERIOD DRY.
&&
.LONG TERM /SUNDAY THROUGH THURSDAY/...
STRONG STORM SYSTEM SUNDAY NIGHT CAUSING A VARIETY OF WEATHER...
BITTERLY COLD WEATHER MIDWEEK...
SATURDAY...HIGH PRESSURE SHIFTS OFF THE MID ATLANTIC COAST AND OUT
TO SEA. SOUTHWEST WINDS OVER SOUTHERN NEW ENGLAND HELP USHER MILDER
AIR INTO THE REGION. 850 MB TEMPERATURES WARM ALL THE WAY TO +4C TO
+5C BY EVENING. HIGHS IN THE LOW TO MID 40S. LOWS SATURDAY NIGHT IN
THE 20S TO MID 30S EXCEPT UPPER 30S ON THE ISLANDS.
SUNDAY AND SUNDAY NIGHT...UPPER LEVEL ENERGY WILL HEAD NORTHEAST
FROM THE TENNESSEE VALLEY AND HELP INTENSIFY A LOW PRESSURE SYSTEM
OFF THE NEW JERSEY COAST SUNDAY NIGHT. THE LOW ORIGINATES IN THE
GULF OF MEXICO SATURDAY EVENING AND RACES NORTHEAST TO THE NEW
JERSEY COAST SUNDAY EVENING...THEN CONTINUES RACING TO A POSITION
JUST SOUTH OF NOVA SCOTIA MONDAY MORNING. MODELS HAVE COME INTO
QUITE GOOD AGREEMENT ON THE RAPID INTENSIFICATION OF THIS SYSTEM AS
IT PASSES NEAR OR SOUTH OF NANTUCKET SUNDAY NIGHT. THE NAM IS
WARMEST AND HAS BEEN DISREGARDED...IN FAVOR MORE OF A ECMWF/ECMWF
ENSEMBLE/GFS/UKMET SOLUTION WHICH IS A TAD FARTHER SOUTHEAST AND
COOLER THAN PREVIOUS SOLUTIONS.
THIS STORM WILL BRING A VARIETY OF IMPACTS. WE WILL BE STARTING OFF
VERY WARM ON SUNDAY...WITH HIGHS IN THE 40S THROUGHOUT THE FORECAST
AREA. RAIN IS FORECAST TO MOVE IN FROM SOUTH TO NORTH IN THE MID TO
LATE AFTERNOON. THE RAIN MAY BECOME HEAVY AT TIMES SUNDAY NIGHT AS
ALL MODELS SHOW VERY STRONG 700 MB OMEGA BETWEEN 00Z AND 03Z MONDAY.
THE 850-700 MB THICKNESS LINE OF 1540...OFTEN DENOTING THE RAIN/SNOW
LINE...IS FORECAST TO STRETCH FROM THE SOUTHERN BERKSHIRES
NORTHEASTWARD TO CAPE ANN AT 00Z. DESPITE ACTUAL WINDS FROM THE
NORTHEAST TO EAST...THE AGEOSTROPHIC SURFACE WIND IS FROM THE NORTH
WHICH COULD LEAD TO MORE LOW-LEVEL COLD AIR DRAINAGE THAN ONE WOULD
OTHERWISE THINK. GFS AND ECMWF SURFACE TEMPERATURES SHOW THE 32
DEGREE LINE A HAIR SOUTH OF THE 1540 THICKNESS LINE...WHICH MAY
SPELL THE POTENTIAL FOR A NARROW SWATH OF FREEZING RAIN. THIS WOULD
BE MOST LIKELY IN CENTRAL MA NORTHEASTWARD THROUGH THE MERRIMACK
VALLEY TO CAPE ANN...PERHAPS AS FAR SOUTHWEST AS THE SPRINGFIELD
AREA. IN NORTHWEST MA AND SOUTHERN NH...ANY RAIN SHOULD TURN
DIRECTLY TO SNOW.
THE FACT THAT THIS IS SUCH A QUICK-HITTING SYSTEM SHOULD WORK TO OUR
BENEFIT. RAINFALL TOTALS IN EASTERN CT/RHODE ISLAND/SOUTHEAST MA
COULD REACH 1 TO 1.5 INCHES. THIS IS NOT ENOUGH TO CAUSE RIVER
FLOODING BUT MAY CAUSE SOME LOCALIZED STORM DRAINAGE TYPE OF
FLOODING. THE DURATION OF ANY FREEZING RAIN WILL ONLY BE ABOUT 2-6
HOURS...AND THUS AMOUNTS WOULD LIKELY ONLY REACH A FEW TENTHS...NOT
ENOUGH FOR A WARNING...BUT AN ADVISORY COULD BE NEEDED. AND AS FOR
SNOW...WE ARE THINKING THAT ACCUMULATIONS IN NW MA AND SOUTHERN NH
COULD REACH A FEW INCHES AFTER THE CHANGEOVER FROM RAIN...BUT ALL
PRECIPITATION WILL BE ENDING FROM SW TO NE ACROSS THE REGION BY 06Z
MONDAY - JUST AFTER MIDNIGHT...SO PROBABLY STAYING JUST BELOW
ADVISORY CRITERIA. OBVIOUSLY...WE WILL HAVE A BETTER HANDLE WITH
THIS SYSTEM AS TIME GETS CLOSER.
MONDAY THROUGH THURSDAY...AFTER THE STORM SYSTEM DEPARTS EARLY
MONDAY...ATTENTION WILL THEN FOCUS ON THE BITTERLY COLD WEATHER
THAT WILL GRIP OUR REGION AROUND THE NEW YEARS HOLIDAY. IN
GENERAL THE WEATHER WILL BE DRY THROUGH THAT PERIOD ALTHOUGH THERE
ARE DIFFERENCES IN TIMING OF WEAK LOW PRESSURE SYSTEMS THAT PASS
EITHER NORTH OF SOUTH OF US ON VARIOUS MODELS. LET/S CALL IT
PARTLY SUNNY BY DAY AND PARTLY CLOUDY BY NIGHT THROUGH THE PERIOD.
THE ONE THING THAT IS FOR SURE IS THAT NORTHWESTERLY FLOW CAUSES
FRIGID AIR TO GRADUALLY SEEP INTO SOUTHERN NEW ENGLAND STARTING
MONDAY AND BY WEDNESDAY AND THURSDAY WE ARE IN THE DEEP FREEZE.
THE GFS HAS THE DEEP FREEZE ARRIVING A DAY LATER AND LASTING
LONGER THAN THE ECMWF. BUT IN EITHER CASE...850 MB TEMPERATURES
EVENTUALLY PLUNGE TO BETWEEN -20C AND -25C...WITH THE POSSIBILITY
OF -30C IN NORTHERN NEW ENGLAND.
WE ARE FORECASTING OVERNIGHT LOWS TO REACH BELOW ZERO IN SOUTHERN
NH ON NEW YEARS EVE/TUE NIGHT/ AND ABOUT 5 BELOW ZERO THERE ON
WEDNESDAY NIGHT. THIS MAY BE EVEN BE TOO CONSERVATIVE. LOWS WILL
REACH THE SINGLE DIGITS AND LOWER TEENS ACROSS THE REST OF
INTERIOR SOUTHERN NEW ENGLAND BOTH NIGHTS...EXCEPT MID TO UPPER
TEENS SOUTH COAST AND LOWER 20S ON THE ISLANDS. WIND CHILL INDICES
COULD REACH 10 TO 15 BELOW ZERO IN THE EARLY MORNING HOURS ON WED
AND THU ACROSS NORTHERN AND WESTERN MA AND IN SOUTHERN NH.
&&
.AVIATION /08Z FRIDAY THROUGH TUESDAY/...
FORECASTER CONFIDENCE LEVELS...
LOW...LESS THAN 30 PERCENT.
MODERATE...30 TO 60 PERCENT.
HIGH...GREATER THAN 60 PERCENT.
NEAR TERM /THROUGH SATURDAY NIGHT/...HIGH CONFIDENCE.
9Z UPDATE...
VFR. WILL SEE SCT-BKN CIGS DEVELOPING ACROSS THE TERMINALS THROUGH
THE DAY NO LOWER THAN LOW-END VFR. PREVAILING WESTERLY WIND FLOW
WITH INFREQUENT GUSTS AROUND 20 KTS. ACTIVITY CLEARS OUT OVERNIGHT
AS WINDS DIMINISH AND TURN SOUTHWESTERLY.
MID- TO HIGH-LEVEL CLOUDS BACK ON THE INCREASE SATURDAY INTO
SATURDAY NIGHT WITH SOUTH-SOUTHWESTERLY FLOW. WILL SEE A BRIEF
PERIOD OF STRONG WINDS ON SATURDAY WITH GUSTS AROUND 20 KTS...
STRONGER FOR SOUTH-SOUTHEAST SHORELINE TERMINALS WITH GUSTS UP TO
30 KTS.
KBOS TAF...HIGH CONFIDENCE IN TAF.
KBDL TAF...HIGH CONFIDENCE IN TAF.
OUTLOOK...SATURDAY THROUGH TUESDAY...
SATURDAY THROUGH EARLY SUNDAY AFTERNOON...HIGH CONFIDENCE. VFR.
SUNDAY AFTERNOON THROUGH MONDAY...MODERATE CONFIDENCE. CIGS AND
VSBYS WILL LOWER TO MVFR IN DEVELOPING RAIN SUNDAY AFTERNOON AND
EVENING. WIDESPREAD IFR SUNDAY NIGHT. PRECIPITATION MAY CHANGE TO
ALL SNOW IN NW MA AND SOUTHERN NH EARLY SUNDAY NIGHT. THERE COULD
BE A BAND OF FREEZING RAIN IN CENTRAL AND NORTHEAST MA. RAIN MAY
BE HEAVY AT TIMES IN RI AND SOUTHEAST MA. ALL PRECIPITATION ENDS
SHORTLY AFTER MIDNIGHT MONDAY MORNING. CONDITIONS IMPROVING TO VFR
MONDAY.
TUE...MODERATE TO HIGH CONFIDENCE. VFR.
&&
.MARINE...
FORECASTER CONFIDENCE LEVELS...
LOW...LESS THAN 30 PERCENT.
MODERATE...30 TO 60 PERCENT.
HIGH...GREATER THAN 60 PERCENT.
NEAR TERM /THROUGH SATURDAY NIGHT/...HIGH CONFIDENCE.
WESTERLY WINDS WILL REMAIN BRISK TODAY...YET INFREQUENT GUSTS
EXCEEDING 25 KTS. WILL REVERT SMALL-CRAFT HEADLINES TO ADVISORIES
FOR HAZARDOUS SEAS. HEADLINES SHOULD DROP OFF DURING THE EVENING
AS WINDS RELAX AND REVERT OUT OF THE SOUTHWEST ALLOWING SEAS TO
DIMINISH.
SOUTHWEST WINDS WILL BE BRISK ON SATURDAY RESULTING IN SEAS TO
BUILD 7 TO 9 FEET OVER THE SOUTH-SOUTHEAST WATERS WHERE GUSTS UP
TO 30 KTS WILL BE POSSIBLE. WINDS EXPECTED TO RELAX SATURDAY
NIGHT ALLOWING FOR SEAS TO DEAMPLIFY.
OUTLOOK...SATURDAY THROUGH TUESDAY...
MODERATE CONFIDENCE.
SMALL CRAFT ADVISORIES WILL PROBABLY BE NEEDED SAT AS SOUTHWEST
WINDS COULD GUST TO 20 TO 30 KT OVER THE SOUTHERN AND EASTERN
WATERS AND SEAS COULD REACH 5 TO 7 FT OVER THE SOUTHEASTERN OUTER
WATERS.
SUNDAY INTO MONDAY...STRONG COASTAL LOW PRESSURE MOVES UP THE
EAST COAST AND INTENSIFIES NEAR OR SOUTH OF NANTUCKET SUNDAY NIGHT
REACHING NOVA SCOTIA MONDAY MORNING. WINDS WILL BECOME
SOUTHEAST...THEN NORTHEAST...THEN NORTHWEST AS THE LOW PASSES.
WINDS COULD GUST TO 25 TO 30 KT AT TIMES OVER THE SOUTHEAST
WATERS BUT GALES ARE NOT EXPECTED AT THIS TIME. SEAS WILL BE QUITE
ROUGH...BUILDING UP TO 6 TO 10 FT JUST OFF THE COAST AND TO 12 FT
OVER THE OUTER WATERS SUNDAY NIGHT...SLOWLY SUBSIDING ON MONDAY.
TUESDAY...WINDS AND SEAS SUBSIDE TO BELOW SMALL CRAFT ADVISORY
LEVELS.
TUESDAY NIGHT...THERE IS THE POTENTIAL FOR SOME FREEZING SPRAY
OVER THE WATERS OFF OF NORTHERN MA LATE AT NIGHT AS VERY COLD
TEMPERATURES MOVE OVER THE REGION.
&&
.BOX WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
MA...NONE.
NH...NONE.
RI...NONE.
MARINE...SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS UNTIL 3 AM EST
SATURDAY FOR ANZ250-254-255.
SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS UNTIL 10 PM EST THIS
EVENING FOR ANZ256.
&&
$$
SYNOPSIS...SIPPRELL/GAF
NEAR TERM...SIPPRELL
SHORT TERM...SIPPRELL
LONG TERM...GAF
AVIATION...SIPPRELL/GAF
MARINE...SIPPRELL/GAF
AREA FORECAST DISCUSSION
NWS TAMPA BAY RUSKIN FL
705 PM EST SAT DEC 28 2013
.UPDATE (TONIGHT AND SUNDAY)...
00Z WATER VAPOR AND H4 RAP ANALYSIS SHOWS A COMPLEX UPPER LEVEL
PATTERN UNFOLDING ACROSS THE CONUS. MAIN FEATURE OF NOTE FOR OUR
FORECAST IS A WELL DEFINED AND ENERGETIC SHORTWAVE THAT IS STARTING
TO BECOME NEGATIVELY TILTED AS IT EJECTS EASTWARD THROUGH THE DEEP
SOUTH. WV IMAGERY SHOWS ABUNDANT MID/UPPER LEVEL SOUTHERN STREAM
MOISTURE BEING DRAWN UP OVER THE EASTERN GULF OF MEXICO AND FLORIDA
PENINSULA THIS EVENING. DCVA AND ASSOCIATED HEIGHT FALLS AHEAD OF
THE TROUGH AXIS ARE SPREADING EASTWARD ACROSS THE NORTHERN GULF OF
MEXICO THIS EVENING AND HAVE FORCED AN AREA OF SURFACE CYCLOGENESIS
THAT IS ABOUT TO MOVE ASHORE ALONG THE FLORIDA PANHANDLE COAST. AS
IT TYPICAL IN THESE SITUATIONS...THE DEEP LAYER SYNOPTIC/QG FORCING
OVER THE GULF IS ERUPTING CLUSTERS OF THUNDERSTORMS OVER THE LOOP
CURRENT. THESE DO NOT SEEM THAT FAR OFF OUR COAST...HOWEVER...THIS
DEEP CONVECTION WILL TEND TO FADE AS IT TRIES TO MOVE EAST AND
ENCOUNTERS THE WEAKER INSTABILITY ASSOCIATED WITH THE COOLER SHELF
WATERS. WE WILL HAVE TO WAIT A LITTLE LONGER FOR THE DEEP LAYER
FORCING TO ARRIVE FOR OUR RAIN CHANCES TO REALLY GO UP. IN
FACT...THE HEIGHT FALLS TO OUR WEST HAVE ACTED TO AMPLIFY THE
RIDGING OVER OUR HEADS THROUGH THE DAY AND OUR FLOW ALOFT CURRENTLY
IS ALMOST ANTI-CYCLONIC IN NATURE. THIS IS ONLY A SHORT TERM
TREND...AS THE SYNOPTIC FORCING IS ON ITS WAY.
REST OF TONIGHT...UPPER TROUGH WILL PIVOT THROUGH THE DEEP SOUTH
WITH THE ASSOCIATED SURFACE REFLECTION/LOW LIFTING NORTHEAST THROUGH
GA WHILE CONTINUING TO DEEPEN. A COLD FRONT TRAILING SOUTH FROM THIS
LOW WILL SWING INTO THE EASTERN GULF OF MEXICO AND BE APPROACHING
THE FLORIDA WEST COAST SUNDAY MORNING. THE FORECAST PHILOSOPHY HAS
NOT CHANGED MUCH SINCE THE AFTERNOON PACKAGE IN TERMS OF TIMING...
DURATION...AND STRENGTH OF THE PRE-FRONTAL SQUALL LINE THAT IS
EXPECTED TO IMPACT THE REGION LATER TONIGHT INTO SUNDAY. THE DEEPER
INTO THE NIGHT WE GO...THE HIGHER THE RAIN CHANCES WILL BECOME AS
THE DEEP LAYER FORCING BEGINS TO OVERSPREAD. THIS WILL BE ESPECIALLY
TRUE FOR THE NATURE COAST ZONES...WHERE RAIN CHANCES REACH LIKELY TO
CATEGORICAL BEFORE SUNRISE. FURTHER SOUTH...SCATTERED SHOWERS ARE
CERTAINLY POSSIBLE...BUT THE ORGANIZED BAND OF CONVECTION WILL
LIKELY HOLD OFF UNTIL DAWN/THE DAYLIGHT HOURS. DURING SUNDAY MORNING
THE PRE-FRONTAL BAND OF SHOWERS/STORMS WILL PIVOT EAST AND SOUTHEAST
INTO THE TAMPA BAY REGION AND THEN INLAND AND DOWN THE SUNCOAST. THE
BEST CHANCES FOR A SOLID/ORGANIZED BAND OF CONVECTION WILL BE FROM
TAMPA BAY NORTHWARD UP THE NATURE COAST AS THESE AREA WILL BE
REACHED FIRST...AND THE LONGER INTO THE DAY WE GO...THE STRONGER
SUPPORT FOR LIFT WILL BE EJECTING NORTHWARD AND AWAY FROM THE
REGION. THIS IS A FAIRLY COMMON OCCURRENCE DURING THE COOL SEASON
FOR US...WITH THE MAIN DYNAMICS/KINEMATICS QUICKLY EXITING AS THE
FRONT ARRIVES. EVEN WITH THAT SAID...THE CLOSE PASSAGE OF THE
SHORTWAVE...AND FAVORABLE AND CLOSE TRACK OF THE LOW SHOULD ALLOW
THE NORTHERN HALF OF THE AREA TO SEE THE CATEGORICAL RAIN CHANCES.
EVEN FURTHER SOUTH...THE BAND MAY NOT BE AS ORGANIZED AS WE HEAD
INTO THE AFTERNOON...BUT STILL FEEL MOST LOCATIONS WILL SEE SOME
RAIN FROM THIS SYSTEM. THE HIGH RESOLUTION ENSEMBLE GUIDANCE SUITE
IS IN VERY GOOD AGREEMENT WITH THIS BAND OF CONVECTION...ADDING SOME
CONFIDENCE TO THE FORECAST.
SEVERE POTENTIAL APPEARS LIMITED. AS MENTIONED...THE QUICK EXIT OF
THE ENERGY TO THE NORTH WILL TAKE THE MAIN LOW LEVEL JET WITH IT.
LOW LEVEL JET WILL BE WEAKENING AND VEERING WITH TIME TOMORROW
DIMINISHING THE THREAT FOR STRONGER STORMS WITH TIME. THERE IS SOME
POTENTIAL FOR SOME STRONGER WIND GUSTS LATE TONIGHT INTO SUNDAY
MORNING ASSOCIATED WITH ANY ORGANIZED QLCS FEATURES...MAINLY FOR THE
NATURE COAST DOWN POTENTIALLY AS FAR SOUTH AS THE TAMPA BAY AREA.
&&
.AVIATION...
29/00Z-30/00Z...BKN VFR CIGS THIS EVENING. CONDITIONS DETERIORATE AS
FRONT APPROACHES WITH MVFR CIGS VCSH AND TEMPO IFR (MAINLY CIGS BUT
SOME BR) STARTING AROUND 06Z. MVFR CIGS AND VCSH CONTINUE THROUGH
SUN AS THE FRONT CROSSES THE TERMINALS WITH VCTS...FROM 12Z IN THE
NORTH TO 18Z IN THE SOUTH...WHICH MAY BRING IFR CONDITIONS. SE AND
SOUTH WINDS GRADUALLY VEER...BECOMING WEST OR NW VERY LATE IN THE
PERIOD.
&&
.MARINE...
CONDITIONS OVER THE WATERS WILL DETERIORATE TO SCEC...POSSIBLY
SCA...CONDITIONS OVERNIGHT. THE FRONT WILL MOVE THROUGH THE WATERS
FROM NORTHWEST TO SOUTHEAST LATE TONIGHT THROUGH SUNDAY...WITH WINDS
SHIFTING TO THE NORTHWEST AND NORTH AND LOWERING BELOW SCEC NO LATER
THAN SUNDAY NIGHT.
&&
.PRELIMINARY POINT TEMPS/POPS...
TPA 69 76 62 74 / 50 90 20 20
FMY 69 81 66 80 / 40 80 30 30
GIF 66 78 60 75 / 50 90 20 20
SRQ 69 76 63 74 / 50 90 20 20
BKV 68 76 55 73 / 60 90 20 20
SPG 68 75 62 74 / 50 90 20 20
&&
.TBW WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
GULF WATERS...NONE.
&&
$$
UPDATE...MROCZKA
AVIATION...RUDE
AREA FORECAST DISCUSSION
NWS TALLAHASSEE FL
640 AM EST Fri Dec 27 2013
Updated aviation discussion.
.NEAR TERM [Today and Tonight]...
Early morning surface analysis reveals the forecast area locked in
northeasterly flow with an approximately 1030mb high pressure
centered to the north and west (Arklatex to Kentucky). This
surface flow pattern exists up the east coast, and over much of
the Gulf of Mexico. Higher thetae air is displaced well to the
south over south Florida and the southern Gulf of Mexico.
Meanwhile, the weather over our forecast area is relatively
unchanged from the past 12-24 hours with cloudy, cool conditions
and some intermittent very light rain showers. This should
continue during the day today with a mixture of low and mid level
cloud decks. RAP analysis shows a significant 850mb dewpoint
gradient bisecting our area from SW-NE (roughly from PAM-FZG).
This is confirmed by comparing the 00z sounding from TAE with ones
to the north and west (LIX, BMX, FFC). Therefore, the southeastern
half of our area is situated in a region of greater low-level
moisture. This is where some light rain showers or patchy drizzle
will be possible today. Some weak isentropic ascent is forecast in
the 290-295K planes; the ascending flow in these layers is only
around 5-10 knots so the forcing should be fairly limited.
However, the forcing should be sufficient for drizzle or light
showers, and this is confirmed by some weak returns on the TLH
radar over the past few hours. The isentropic ascent should both
deepen and increase overnight as wind fields increase - and this
is when rain showers should spread into much of the forecast area.
.SHORT TERM [Saturday through Sunday]...
Fairly active weather pattern stetting up for the weekend as an
upper low evolving over nrn Mexico/SW TX today ejects enewd across
the central Gulf coast states/sern US this weekend as a
deamplifying trough. Ahead of this system, responding sly low
level winds across the Gulf coast/ern GoM this weekend will
increase low level WAA/ascent and bring both an increase in clouds
and rising PoPs Saturday and Sunday. Rain showers are expected to
develop over the wrn counties Saturday into Saturday night,
spreading ewd across remainder of the area into Sunday. This will
keep things seasonably cool/wet Saturday over sern AL, inland
parts of the FL panhandle into swrn GA. This system will be fast
moving so rain totals are expected to be around 1-1.5 inches over
most areas. Sunday should see fairly steady improvements with rain
chances ending from west to east through the day. Given the expect
cool air and little time for recovery, expect thunderstorms will
remain most likely over the Gulf of Mexico. However will include
slgt chance or chance of tstms spreading inland Saturday afternoon
into Sunday as warm sector becomes better defined over the nern
Gulf. Overall risk of severe storms appears fairly low attm given
the expected limited instability. Regardless, increasing low and
deep layer shear suggest an isolated strong to severe storm
remains possible.
.LONG TERM [Sunday Night Through Friday]...
The extended period begins with a cold front pushing through the
Tri-state region with rain ending from west to east Sunday. This
will be quickly followed by a dry cold front Monday as an amplifying
upper trough over the nation`s midsection moves east. In its wake,
we can expect at least two more days with cooler and dry weather.
Wednesday night through Thursday, cyclogenesis is forecast to
develop along the Central Gulf coast in response to the next
shortwave dropping down into the Southern plains. The surface low
with this system is currently forecast to be rather weak and pass
over or south of our coastal waters. For now, will just introduce
slight PoPs for all zones for Thursday. Temps will be at or below
seasonal levels through the period.
&&
.AVIATION...
[Through 12Z Saturday] Ceilings will remain today, but should be
mostly of the VFR variety. There will be a better chance for MVFR
CIGS overnight, mainly after 03z and at ECP, TLH, and VLD. Some -DZ
and -SHRA will affect TLH and VLD through around 19-20z, before a
brief lull in the late afternoon. -SHRA should begin to spread over
much of the area overnight, but significant visibility restrictions
are not expected.
&&
.MARINE...
Northeast winds will remain at cautionary levels today and
tonight, and hold in the 15-20 kt range Saturday as winds switch
to a more easterly direction and rain chances increase. By
Saturday night into Sunday winds will become more out of the
southeast and increase over wrn legs to near advisory criteria as
a surface low moves into the FL panhandle. Winds and seas are
expected to subside early next week.
&&
.FIRE WEATHER...
Relative humidity will remain well above critical thresholds.
Therefore, red flag conditions are not expected. Wetting rains are
likely this weekend.
&&
.HYDROLOGY...
The Apalachicola River at Blountstown is expected to remain in
minor flood stage through the weekend with releases from
Woodruff Dam. The Kinchafoonee Creek`s crest near Dawson is
forecast to just barely reach minor flood stage early Friday
morning and drop below minor flood stage on Friday evening. The
Choctawhatchee River at Caryville is expected to barely reach
minor flood stage on Friday morning and drop below minor flood
stage Saturday morning.
Early projections on rainfall this weekend are in the 1-2" range.
This should help to keep river levels elevated.
&&
.PRELIMINARY POINT TEMPS/POP...
Tallahassee 60 48 66 58 69 / 20 30 50 70 50
Panama City 61 50 63 58 65 / 20 50 60 80 40
Dothan 59 45 57 49 62 / 10 30 70 80 40
Albany 58 42 58 51 66 / 10 20 60 80 50
Valdosta 58 45 67 57 70 / 20 30 50 70 60
Cross City 64 51 73 61 73 / 30 30 40 60 60
Apalachicola 62 52 67 59 68 / 30 40 50 70 50
&&
.TAE Watches/Warnings/Advisories...
FL...None.
GA...None.
AL...None.
GM...None.
&&
$$
NEAR TERM...Lamers
SHORT TERM...Evans
LONG TERM...Barry
AVIATION...Lamers
MARINE...Evans
FIRE WEATHER...Lamers
HYDROLOGY...DVD/McDermott
AREA FORECAST DISCUSSION
NWS TALLAHASSEE FL
425 AM EST Fri Dec 27 2013
.NEAR TERM [Today and Tonight]...
Early morning surface analysis reveals the forecast area locked in
northeasterly flow with an approximately 1030mb high pressure
centered to the north and west (Arklatex to Kentucky). This
surface flow pattern exists up the east coast, and over much of
the Gulf of Mexico. Higher thetae air is displaced well to the
south over south Florida and the southern Gulf of Mexico.
Meanwhile, the weather over our forecast area is relatively
unchanged from the past 12-24 hours with cloudy, cool conditions
and some intermittent very light rain showers. This should
continue during the day today with a mixture of low and mid level
cloud decks. RAP analysis shows a significant 850mb dewpoint
gradient bisecting our area from SW-NE (roughly from PAM-FZG).
This is confirmed by comparing the 00z sounding from TAE with ones
to the north and west (LIX, BMX, FFC). Therefore, the southeastern
half of our area is situated in a region of greater low-level
moisture. This is where some light rain showers or patchy drizzle
will be possible today. Some weak isentropic ascent is forecast in
the 290-295K planes; the ascending flow in these layers is only
around 5-10 knots so the forcing should be fairly limited.
However, the forcing should be sufficient for drizzle or light
showers, and this is confirmed by some weak returns on the TLH
radar over the past few hours. The isentropic ascent should both
deepen and increase overnight as wind fields increase - and this
is when rain showers should spread into much of the forecast area.
.SHORT TERM [Saturday through Sunday]...
Fairly active weather pattern stetting up for the weekend as an
upper low evolving over nrn Mexico/SW TX today ejects enewd across
the central Gulf coast states/sern US this weekend as a
deamplifying trough. Ahead of this system, responding sly low
level winds across the Gulf coast/ern GoM this weekend will
increase low level WAA/ascent and bring both an increase in clouds
and rising PoPs Saturday and Sunday. Rain showers are expected to
develop over the wrn counties Saturday into Saturday night,
spreading ewd across remainder of the area into Sunday. This will
keep things seasonably cool/wet Saturday over sern AL, inland
parts of the FL panhandle into swrn GA. This system will be fast
moving so rain totals are expected to be around 1-1.5 inches over
most areas. Sunday should see fairly steady improvements with rain
chances ending from west to east through the day. Given the expect
cool air and little time for recovery, expect thunderstorms will
remain most likely over the Gulf of Mexico. However will include
slgt chance or chance of tstms spreading inland Saturday afternoon
into Sunday as warm sector becomes better defined over the nern
Gulf. Overall risk of severe storms appears fairly low attm given
the expected limited instability. Regardless, increasing low and
deep layer shear suggest an isolated strong to severe storm
remains possible.
.LONG TERM [Sunday Night Through Friday]...
The extended period begins with a cold front pushing through the
Tri-state region with rain ending from west to east Sunday. This
will be quickly followed by a dry cold front Monday as an amplifying
upper trough over the nation`s midsection moves east. In its wake,
we can expect at least two more days with cooler and dry weather.
Wednesday night through Thursday, cyclogenesis is forecast to
develop along the Central Gulf coast in response to the next
shortwave dropping down into the Southern plains. The surface low
with this system is currently forecast to be rather weak and pass
over or south of our coastal waters. For now, will just introduce
slight PoPs for all zones for Thursday. Temps will be at or below
seasonal levels through the period.
&&
.AVIATION...
[Through 06Z Saturday] Ceilings are expected through the TAF
period with BKN-OVC skies, but these should mainly be of the VFR
variety. There could be some brief periods of MVFR, particularly
at ECP, TLH, or VLD. However, probabilistic guidance indicates
that the chances of this happening are around 20-30%. Therefore,
we indicated a VFR forecast. Some very light rain showers or
drizzle is expected to develop this morning in the Florida Big
Bend, which could affect TLH and VLD. Showers spread inland
tonight - to TLH, VLD, and ECP prior to 06z, and ABY and DHN after
06z (the end of the TAF period).
&&
.MARINE...
Northeast winds will remain at cautionary levels today and
tonight, and hold in the 15-20 kt range Saturday as winds switch
to a more easterly direction and rain chances increase. By
Saturday night into Sunday winds will become more out of the
southeast and increase over wrn legs to near advisory criteria as
a surface low moves into the FL panhandle. Winds and seas are
expected to subside early next week.
&&
.FIRE WEATHER...
Relative humidity will remain well above critical thresholds.
Therefore, red flag conditions are not expected. Wetting rains are
likely this weekend.
&&
.HYDROLOGY...
The Apalachicola River at Blountstown is expected to remain in
minor flood stage through the weekend with releases from
Woodruff Dam. The Kinchafoonee Creek`s crest near Dawson is
forecast to just barely reach minor flood stage early Friday
morning and drop below minor flood stage on Friday evening. The
Choctawhatchee River at Caryville is expected to barely reach
minor flood stage on Friday morning and drop below minor flood
stage Saturday morning.
Early projections on rainfall this weekend are in the 1-2" range.
This should help to keep river levels elevated.
&&
.PRELIMINARY POINT TEMPS/POP...
Tallahassee 60 48 66 58 69 / 20 30 50 70 50
Panama City 61 50 63 58 65 / 20 50 60 80 40
Dothan 59 45 57 49 62 / 10 30 70 80 40
Albany 58 42 58 51 66 / 10 20 60 80 50
Valdosta 58 45 67 57 70 / 20 30 50 70 60
Cross City 64 51 73 61 73 / 30 30 40 60 60
Apalachicola 62 52 67 59 68 / 30 40 50 70 50
&&
.TAE Watches/Warnings/Advisories...
FL...None.
GA...None.
AL...None.
GM...None.
&&
$$
NEAR TERM...Lamers
SHORT TERM...Evans
LONG TERM...Barry
AVIATION...Lamers
MARINE...Evans
FIRE WEATHER...Lamers
HYDROLOGY...DVD/McDermott
AREA FORECAST DISCUSSION
NWS GOODLAND KS
413 PM MST SAT DEC 28 2013
.SHORT TERM...(THIS EVENING THROUGH SUNDAY)
ISSUED AT 117 PM MST SAT DEC 28 2013
THE LAST WEEKEND OF 2013 KICKED OFF YESTERDAY WITH WELL ABOVE-NORMAL
TEMPERATURES AND WILL END WITH A VERY COLD SUNDAY. AN ARCTIC COLD
FRONT ON THE WAY TODAY WILL BRING THE COLD AIR AS WELL AS STRONG
WINDS. A FEW FLURRIES ARE POSSIBLE TONIGHT INTO EARLY SUNDAY...BUT
THE MAIN IMPACT OF THIS FRONT WILL BE THE WIND AND COLD. ON SUNDAY
SKIES WILL BECOME MOSTLY SUNNY BUT TEMPERATURES WILL HAVE A TOUGH
TIME GETTING ABOVE FREEZING.
TODAY...SATURDAY...SUNNY AND MILD TO START...BECOMING WINDY AND
COLD. FRONTAL PASSAGE LOOKS TO OCCUR IN THE EARLY AFTERNOON...WITH A
REINFORCING SHOT OF COLD AIR TONIGHT. AHEAD OF THE FRONT IT WILL BE
A NICE DAY SIMILAR TO YESTERDAY WITH SUNNY SKIES...MILD TEMPS...AND
A LIGHT WEST/SOUTHWESTERLY WIND. HIGHS MIGHT EVEN APPROACH RECORD
VALUES TODAY WHICH ARE IN THE MID TO UPPER 60S FOR MOST STATIONS. /RECORD
HIGH OF 67 AT HILL CITY LOOKS TO HAVE THE BEST CHANCE OF BEING
BROKEN OUT OF THE FOUR ASOS SITES./ THE INITIAL FRONT WILL RACE
SOUTH ACROSS THE REGION EARLY THIS AFTERNOON...BRINGING GUSTY WINDS.
DECIDED TO REMOVE THE BLOWING DUST FROM THE WX GRID AS EXPECT ANY
BLOWING DUST/DIRT TO BE VERY LIMITED SPATIALLY/TEMPORALLY BASED ON
THE LATEST SHORT-TERM GUIDANCE. MID/HIGH LEVEL CLOUD COVER
ASSOCIATED WITH THE FRONT WILL ARRIVE LATER THIS AFTERNOON...WITH
LOW-LEVEL STRATUS CLOUDS THIS EVENING.
TONIGHT...STRONG PRESSURE RISES SUPPORT WINDY CONDITIONS THROUGH THE
NIGHT WITH LIGHT SNOW POSSIBLE IN EASTERN COLORADO. OVERCAST SKIES
WITH A LOW STRATUS DECK IN THE EVENING AND MID-LEVEL CLOUDS
PERSISTING THROUGH MOST OF THE NIGHT. WINDS WILL CONTINUE AS STRONG
PRESSURE RISES /5-8 MB/HR/ ARE EXPECTED AND MIXING OCCURS. A FEW
FLURRIES/LIGHT SNOW POSSIBLE IN EASTERN COLORADO AND PORTIONS OF NW
KANSAS WITH THE COMBINATION OF LOW LEVEL MOISTURE AND
FRONTOGENETICAL FORCING IN PLACE. GUIDANCE HAS BEEN QUITE CONSISTENT
RUN-TO-RUN...AND EARLY NCEP RAP AND ESRL RAP RUNS SUPPORT AT LEAST
SOME FLURRIES FOR MOST SPOTS. ACCUMULATIONS ARE NOT EXPECTED TO
AMOUNT TO MUCH...BUT WOULD NOT BE SURPRISED IF WESTERN PARTS OF
CHEYENNE/KIT CARSON COUNTIES IN COLORADO RECEIVE A HALF INCH.
/THOUGH IT WILL BE HARD TO MEASURE WITH ALL THE WIND.../ LOWS WILL
REACH THE SINGLE DIGITS IN MANY LOCATIONS WITH 850MB TEMPS IN THE
-12 TO -15 C RANGE AND STRONG COLD AIR ADVECTION.
TOMORROW...SUNDAY...COLD AND MOSTLY SUNNY. AT DAWN SUNDAY CLOUDS
WILL BE CLEARING FROM NORTHWEST TO SOUTHEAST...BECOMING MOSTLY SUNNY
EVERYWHERE BY THE AFTERNOON. WINDS WILL BE LIGHT OUT OF THE
NORTH/NORTHWEST AT 10 TO 15 MPH. DESPITE THE SUN HIGHS WILL STRUGGLE
TO REACH ABOVE FREEZING AS HIGH PRESSURE STRENGTHENS ACROSS THE
NORTHERN PLAINS.
.LONG TERM...(SUNDAY NIGHT THROUGH SATURDAY)
ISSUED AT 200 PM MST SAT DEC 28 2013
SUNDAY NIGHT-TUESDAY...PERIODIC INCREASES IN MID AND HIGH CLOUDS
EXPECTED UNDER NORTHWEST FLOW ALOFT. NO PRECIPITATION EXPECTED. MAY
SEE SOME BREEZY NORTHWEST WINDS MONDAY AFTERNOON.
LOWS SUNDAY NIGHT AROUND 10 ACROSS THE EAST AND WESTERN PORTIONS OF
CHEYENNE COUNTY COLORADO...LOW TO MID TEENS ELSEWHERE. HIGHS MONDAY
MID 40S TO AROUND 50. MAY HAVE A BIT OF SNOW COVER TO DEAL WITH
ACROSS THE WEST AND HAVE MID 40S IN THAT AREA. ON TUESDAY 850
TEMPERATURES WARM ABOUT 13-15F ACROSS THE AREA SUPPORTING HIGHS IN
THE MID 50S (NORTHEAST) TO MID 60S (WEST). BIAS CORRECTED GRIDS
ALONG THE 2M/MET/MAV ARE SEVERAL DEGREES COOLER. HAVE GENERALLY
BLENDED ALL SOLUTIONS TRYING TO TREND A BIT CLOSER TO 850
TEMPERATURES. HAVE SETTLED ON LOW TO MID 50S FAR NORTHEAST-EAST WITH
UPREAR 50S TO AROUND 60 ACROSS THE WESTERN/SOUTHWESTERN 2/3 OF THE
AREA.
TUESDAY NIGHT-SATURDAY...THERE IS A SLIGHT CHANCE OF LIGHT
PRECIPITATION WEDNESDAY AS A LARGE AREA OF MOISTURE MOVES IN FROM
THE NORTHWEST...AIDED BY APPROACHING LEFT FRONT PORTION OF UPPER
JET. BETTER CHANCES OF PRECIP GENERALLY ACROSS NORTHEAST 1/2 OF THE
FORECAST AREA. THIS SYSTEM EXITS THE AREA EARLY WEDNESDAY NIGHT.
OTHERWISE...A DRY FORECAST EXPECTED. LOWS THROUGH THURSDAY NIGHT IN
THE TEENS TO LOW 20S WITH MID 20S FRIDAY NIGHT. HIGHS WEDNESDAY IN
THE LOW 30S EAST TO LOW/MID 40S FAR WEST...SLOWLY WARMING INTO THE
LOW TO MID 40S (EAST TO WEST) THURSDAY. ON FRIDAY WE SHOULD RETURN
TO ABOVE NORMAL TEMPERATURES WITH UPPER 40S TO MID 50S. A RETURN TO
NEAR NORMAL HIGHS SATURDAY WITH LOW TO MID 40S.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z SUNDAY EVENING)
ISSUED AT 408 PM MST SAT DEC 28 2013
AT KGLD...VFR WILL PREVAIL THROUGH THE EVENING HOURS ALTHOUGH
SURFACE WINDS WILL CONTINUE TO BE ON THE GUSTY SIDE IN THE WAKE OF
AN EARLIER COLD FRONT PASSAGE. THERE IS A CHANCE OF FLIGHT
CATEGORY RESTRICTIONS DURING THE OVERNIGHT HOURS DUE TO LIGHT SNOW
ASSOCIATED WITH THE MAIN UPPER FORCING SWINGING THROUGH. THE
RESTRICTIONS WOULD BE BRIEF IF THEY WERE TO OCCUR...WITH VFR
EXPECTED TO RETURN BY SUNRISE.
AT KMCK...VFR EXPECTED THROUGH THE TAF PERIOD. THERE IS A SLIM
CHANCE OF LOW CIGS IN THE EVENING HOURS...BUT AREAL COVERAGE
EXPECTED TO BE LIMITED BY LOW LEVEL DRYNESS WHICH WILL HAVE TO BE
OVERCOME AND UNFAVORABLE WIND DIRECTION. IT WILL BE BREEZY TO
WINDY THROUGH THE NIGHT...DIMINISHING SUNDAY MORNING.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
CO...NONE.
NE...NONE.
&&
$$
SHORT TERM...JJM
LONG TERM...99
AVIATION...024
AREA FORECAST DISCUSSION
NWS GOODLAND KS
204 AM MST FRI DEC 27 2013
.SHORT TERM...(THIS EVENING THROUGH FRIDAY)
ISSUED AT 1258 PM MST THU DEC 26 2013
A WEAK UPPER LEVEL SHORTWAVE TROUGH DROPPING SOUTH/SOUTHEAST ACROSS
THE HIGH PLAINS BROUGHT SOME CLOUD COVER TO THE REGION THIS MORNING.
LIMITED MID-LEVEL MOISTURE ASSOCIATED WITH THIS DISTURBANCE AND
UNFAVORABLE DYNAMICS MEANS NO PRECIPITATION WITH THIS EVENT.
TOMORROW WILL LIKELY BE THE WARMEST DAY OF THE WEEK FOR MOST
LOCATIONS THANKS TO LOW/MID-LEVEL WARM AIR ADVECTION AND SUNNY SKIES.
HAPPY TO SEE THE NCEP SNOW DEPTH ASSIMILATION DID A PRETTY GOOD JOB
WITH ITS 06Z DAILY UPDATE...REMOVING ALL BUT A SMALL PATCH OF SNOW
COVER IN NORTHEAST RED WILLOW AND WESTERN FURNAS COUNTIES IN NEBRASKA.
SO HAVE MORE CONFIDENCE IN 06Z/12Z CYCLE GUIDANCE IN SW NEBRASKA THAN
EARLIER CYCLES WHICH HAD A WIDE SWATH OF SNOW COVER ACROSS ALL OF SW
NEB AND NORTHEAST COLORADO...WHICH INFLUENCED LOW-LEVEL MODEL TEMP
AND MOISTURE FIELDS /QUITE DRAMATICALLY IN THE CASE OF THE NAM/.
TODAY...THURSDAY...MOSTLY SUNNY AND MILD WITH A LIGHT BREEZE.
DISTURBANCE MOVING SOUTH/SOUTHEAST ACROSS THE HIGH PLAINS THE CAUSE
FOR THE MID/HIGH-LEVEL CLOUDS TODAY. CLOUDS ARE THINNING OUT FROM
EARLIER THIS MORNING WHEN THE WERE OVER WESTERN NEBRASKA AND EASTERN
WYOMING...AND WHILE THE RAP IS A LITTLE AGGRESSIVE ABOUT DEVELOPING
THICKER MID-LEVEL CLOUDS THIS AFTERNOON ALONG I70 BELIEVE THE CLOUD
COVER WILL HAVE MINIMAL IMPACT ON HIGH TEMPS TODAY. WITH THE SURFACE
TROUGH OVER EASTERN COLORADO AND UPPER LEVEL DISTURBANCE MOVING THROUGH
EXPECT ANOTHER DAY OF BREEZY WINDS...DECREASING LATE IN THE
AFTERNOON. PREVIOUS FORECAST HIGHS WERE NUDGED UP JUST A TAD TO
ACCOUNT FOR LESS CLOUD COVER BASED ON HOURLY TEMP TREND THUS FAR.
TONIGHT...A FEW HIGH CLOUDS AND NEAR NORMAL TEMPS. SIMILAR TO LAST
NIGHT LIGHT WINDS ARE EXPECTED TO CONTINUE THROUGH THE NIGHT...AND
GIVEN THE DIRECTION /WESTERLY/ AND THE LOW/MID-LEVEL WARM AIR
ADVECTION THINK MANY SPOTS WILL NOT DIP BELOW THE LOW 20S. /EXCEPT
FOR THE USUAL COLD SPOTS SUCH AS WESTERN CHEYENNE COUNTY COLORADO./
TOMORROW...FRIDAY...SUNNY AND WARM. THE WEAK SURFACE TROUGH ACROSS
EASTERN COLORADO REMAINS IN PLACE AS A BROAD H5 LONGWAVE RIDGE
APPROACHES FROM THE WEST. WINDS WILL BE LIGHT OUT OF THE
WEST/SOUTHWEST...ONLY AIDING IN THE WARMTH. HIGHS WILL BE IN THE LOW
TO MID 60S BASED ON CURRENT GUIDANCE. THE RECORD HIGH AT BURLINGTON
COLORADO MAY BE IN JEOPARDY...WHICH CURRENTLY STANDS AT 65 SET IN
1976. /ELSEWHERE RECORDS ARE WELL ABOVE FORECAST HIGHS./
.LONG TERM...(MONDAY THROUGH THURSDAY)
ISSUED AT 201 AM MST FRI DEC 27 2013
LARGE SCALE PATTERN IS STILL SHOWING THE UPPER TROUGH OVER THE
EASTERN U.S. WITH THE UPPER RIDGE OVER THE WESTERN U.S. THE
EXTENDED STILL LOOKS TO REMAIN DRY WITH TEMPERATURES NEAR TO
SLIGHTLY ABOVE NORMAL...WITH A BRIEF COOL DOWN ON TUESDAY
NIGHT/WEDNESDAY...WARMING UP TOWARDS THE END OF THE EXTENDED.
THE CWA WILL BE UNDER NORTHWEST FLOW ALOFT WITH A MID-UPPER LEVEL
SHORTWAVE TROUGH MOVING THROUGH THE CENTRAL PLAINS ON WEDNESDAY. A
BACK DOOR COLD FRONT WILL MOVE THROUGH THE CWA ON TUESDAY
EVENING...BRINGING IN COLDER TEMPERATURES. THE NEW ECMWF MODEL RUN
BROUGHT IN MUCH COLDER ARCTIC AIR THAN THE OTHER MODELS. SINCE THIS WAS
THE FIRST RUN TO DO THIS...ADJUSTED TEMPS SLIGHTLY FOR LOWS ON
TUESDAY NIGHT/WEDNESDAY MORNING AND HIGHS ON WEDNESDAY AFTERNOON IN
THE NORTHEAST/EASTERN COUNTIES OF THE CWA WHERE THE COLD AIR WILL
FILTER IN. COULD NOT REALLY LOWER TEMPS A WHOLE LOT TO BE IN
AGREEMENT WITH SURROUNDING OFFICES...SO WILL HAVE TO SEE WHAT MODELS
DO TOMORROW TO SEE IF THE ECMWF IS AN OUTLIER. CLOUD COVER WILL
INCREASE ON WEDNESDAY AS THE SHORTWAVE TROUGH MOVES THROUGH AND
SOUNDINGS BECOME MORE SATURATED AT THE MID-UPPER LEVELS...BUT THE EXTENDED
WILL REMAIN DRY. HIGHS SHOULD INCREASE AND BECOME ABOVE NORMAL IN
THE UPPER 40S ON THURSDAY AS THE COLD AIR EXITS THE AREA...WITH THIS
WARMING TREND TO CONTINUE PAST DAY 7.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z FRIDAY NIGHT)
ISSUED AT 1014 PM MST THU DEC 26 2013
VFR EXPECTED AT BOTH KGLD AND KMCK THROUGH THE TAF PERIOD. SURFACE
WINDS WILL BE LIGHT AND MAINLY OUT OF THE WEST WITH A SURFACE
TROUGH NEARLY STATIONARY ACROSS EASTERN COLORADO.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
CO...NONE.
NE...NONE.
&&
$$
SHORT TERM...JJM
LONG TERM...ALW
AVIATION...024
AREA FORECAST DISCUSSION
NWS GOODLAND KS
1017 PM MST THU DEC 26 2013
.SHORT TERM...(THIS EVENING THROUGH FRIDAY)
ISSUED AT 1258 PM MST THU DEC 26 2013
A WEAK UPPER LEVEL SHORTWAVE TROUGH DROPPING SOUTH/SOUTHEAST ACROSS
THE HIGH PLAINS BROUGHT SOME CLOUD COVER TO THE REGION THIS MORNING.
LIMITED MID-LEVEL MOISTURE ASSOCIATED WITH THIS DISTURBANCE AND
UNFAVORABLE DYNAMICS MEANS NO PRECIPITATION WITH THIS EVENT.
TOMORROW WILL LIKELY BE THE WARMEST DAY OF THE WEEK FOR MOST
LOCATIONS THANKS TO LOW/MID-LEVEL WARM AIR ADVECTION AND SUNNY SKIES.
HAPPY TO SEE THE NCEP SNOW DEPTH ASSIMILATION DID A PRETTY GOOD JOB
WITH ITS 06Z DAILY UPDATE...REMOVING ALL BUT A SMALL PATCH OF SNOW
COVER IN NORTHEAST RED WILLOW AND WESTERN FURNAS COUNTIES IN NEBRASKA.
SO HAVE MORE CONFIDENCE IN 06Z/12Z CYCLE GUIDANCE IN SW NEBRASKA THAN
EARLIER CYCLES WHICH HAD A WIDE SWATH OF SNOW COVER ACROSS ALL OF SW
NEB AND NORTHEAST COLORADO...WHICH INFLUENCED LOW-LEVEL MODEL TEMP
AND MOISTURE FIELDS /QUITE DRAMATICALLY IN THE CASE OF THE NAM/.
TODAY...THURSDAY...MOSTLY SUNNY AND MILD WITH A LIGHT BREEZE.
DISTURBANCE MOVING SOUTH/SOUTHEAST ACROSS THE HIGH PLAINS THE CAUSE
FOR THE MID/HIGH-LEVEL CLOUDS TODAY. CLOUDS ARE THINNING OUT FROM
EARLIER THIS MORNING WHEN THE WERE OVER WESTERN NEBRASKA AND EASTERN
WYOMING...AND WHILE THE RAP IS A LITTLE AGGRESSIVE ABOUT DEVELOPING
THICKER MID-LEVEL CLOUDS THIS AFTERNOON ALONG I70 BELIEVE THE CLOUD
COVER WILL HAVE MINIMAL IMPACT ON HIGH TEMPS TODAY. WITH THE SURFACE
TROUGH OVER EASTERN COLORADO AND UPPER LEVEL DISTURBANCE MOVING THROUGH
EXPECT ANOTHER DAY OF BREEZY WINDS...DECREASING LATE IN THE
AFTERNOON. PREVIOUS FORECAST HIGHS WERE NUDGED UP JUST A TAD TO
ACCOUNT FOR LESS CLOUD COVER BASED ON HOURLY TEMP TREND THUS FAR.
TONIGHT...A FEW HIGH CLOUDS AND NEAR NORMAL TEMPS. SIMILAR TO LAST
NIGHT LIGHT WINDS ARE EXPECTED TO CONTINUE THROUGH THE NIGHT...AND
GIVEN THE DIRECTION /WESTERLY/ AND THE LOW/MID-LEVEL WARM AIR
ADVECTION THINK MANY SPOTS WILL NOT DIP BELOW THE LOW 20S. /EXCEPT
FOR THE USUAL COLD SPOTS SUCH AS WESTERN CHEYENNE COUNTY COLORADO./
TOMORROW...FRIDAY...SUNNY AND WARM. THE WEAK SURFACE TROUGH ACROSS
EASTERN COLORADO REMAINS IN PLACE AS A BROAD H5 LONGWAVE RIDGE
APPROACHES FROM THE WEST. WINDS WILL BE LIGHT OUT OF THE
WEST/SOUTHWEST...ONLY AIDING IN THE WARMTH. HIGHS WILL BE IN THE LOW
TO MID 60S BASED ON CURRENT GUIDANCE. THE RECORD HIGH AT BURLINGTON
COLORADO MAY BE IN JEOPARDY...WHICH CURRENTLY STANDS AT 65 SET IN
1976. /ELSEWHERE RECORDS ARE WELL ABOVE FORECAST HIGHS./
.LONG TERM...(FRIDAY NIGHT THROUGH THURSDAY)
ISSUED AT 145 PM MST THU DEC 26 2013
FRIDAY NIGHT-SUNDAY...CONTINUED WARM AND DRY SATURDAY AHEAD OF AN
UPPER TROUGH THAT MOVES THROUGH SATURDAY NIGHT. ON SUNDAY FORECAST
AREA UNDER NORTHWEST FLOW ALOFT. AHEAD OF THE UPPER TROUGH STRONG
NORTH/NORTHWEST WINDS MOVE IN EARLY SATURDAY AFTERNOON WITH
SUSTAINED SPEEDS AROUND 20-30 MPH WITH HIGHER GUSTS. SOME GUSTY
WINDS CONTINUE THROUGH EARLY SATURDAY NIGHT BEFORE SLOWLY DECREASING
AFTER MIDNIGHT AND THROUGH THE DAY SUNDAY. CANT COMPLETELY RULE OUT
SOME VERY LIGHT PRECIPITATION CHANCES EARLY SATURDAY NIGHT AS BETTER
MOISTURE BUT LIMITED DYNAMICS WITH THE UPPER TROUGH MOVE THROUGH.
AFTER MIDNIGHT MOISTURE QUICKLY MOVES AWAY FROM THE AREA WITH NEAR
ZERO CHANCE ON SUNDAY.
LOWS TONIGHT UPPER TEENS TO MID 20S WITH HIGHS SATURDAY MID 50S TO
LOW 60S. LOWS SATURDAY NIGHT IN THE TEENS WITH MID 20S (EAST) TO
LOW/MID 30S FAR WEST SUNDAY.
SUNDAY NIGHT-THURSDAY...FORECAST AREA REMAINS UNDER NORTHWEST FLOW
ALOFT THROUGH THE PERIOD. WEATHER SYSTEMS MOVE THROUGH THE FLOW
SUNDAY NIGHT THEN AGAIN MONDAY NIGHT AND TUESDAY NIGHT.
HOWEVER...DOESNT LOOK LIKE ANY OF THESE PRODUCE ANY PRECIPITATION.
TEMPERATURES SLOWLY WARM MONDAY AND TUESDAY BEFORE COOLING DOWN
WEDNESDAY AND THEN WARMING UP AGAIN THURSDAY.
LOWS SUNDAY NIGHT IN THE TEENS WITH LOW TO MID 20S MONDAY
NIGHT-WEDNESDAY NIGHT. HIGHS MONDAY LOW TO MID 40S ALTHOUGH
GFS/ECMWF 850 TEMPS SUPPORT READINGS A BIT HIGHER. FOR TUESDAY LOW
TO MID 40S EAST WITH UPPER 40S TO LOW 50S WEST. ON WEDNESDAY AN
UNCERTAIN LOW TO MID 40S AS DIFFERENCES SHOW UP IN JUST HOW MUCH
COOLER IT WILL BE WITH LARGE DISPARITY BETWEEN ECMWF/GFS 850
TEMPERATURES. FOR THURSDAY GENERALLY MID TO UPPER 40S...ECMWF
SUGGESTS IT WILL BE WARMER THEN CURRENT FORECAST PER 850
TEMPERATURES WHILE GFS ABOUT 5C COOLER.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z FRIDAY NIGHT)
ISSUED AT 1014 PM MST THU DEC 26 2013
VFR EXPECTED AT BOTH KGLD AND KMCK THROUGH THE TAF PERIOD. SURFACE
WINDS WILL BE LIGHT AND MAINLY OUT OF THE WEST WITH A SURFACE
TROUGH NEARLY STATIONARY ACROSS EASTERN COLORADO.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
CO...NONE.
NE...NONE.
&&
$$
SHORT TERM...JJM
LONG TERM...99
AVIATION...024
AREA FORECAST DISCUSSION
NWS BALTIMORE MD/WASHINGTON DC
1009 PM EST SAT DEC 28 2013
.SYNOPSIS...
LOW PRESSURE WILL MOVE NORTHEAST FROM THE FLORIDA PANHANDLE TONIGHT
TO NEAR HAMPTON ROADS MID DAY SUNDAY BEFORE PASSING MOVING OFFSHORE
OF THE DELMARVA COAST LATE SUNDAY AFTERNOON. HIGH PRESSURE WILL
BUILD OVERHEAD MONDAY BEFORE A REINFORCING COLD FRONT MOVES THROUGH
TUESDAY. HIGH PRESSURE WILL DEVELOP TO OUR NORTH DURING THE MIDDLE
AND LATTER PORTIONS OF NEXT WEEK WHILE LOW PRESSURE DEVELOPS TO OUR
SOUTH. UNSETTLED CONDITIONS ARE POSSIBLE DURING THIS TIME.
&&
.NEAR TERM /THROUGH SUNDAY/...
UPDATE...MOVED UP START TIME OF PRECIP ACROSS SWRN ZONES BY 1-2 HRS.
SENT GRID UPDATE.
AT 01Z...SURFACE HIGH PRESSURE OVER EASTERN NORTH CAROLINA
EXTENDING EAST OFFSHORE. SWLY FLOW AROUND THE HIGH BROUGHT MILD
CONDITIONS ACROSS THE REGION EARLIER TODAY..AND TEMPS ARE STILL
WELL ABOVE NORMAL SEASONAL HIGHS.
OVERNIGHT AND SUNDAY...AS HIGH RETREATS EAST INTO WRN ATLANTIC...
DEVELOPING SURFACE LOW PRESSURE CENTER THAT AT 00Z WAS NEAR
PENSACOLA FL WILL MOVE NORTHEAST...ATTENDED BY A LARGE AREA OF
PRECIPITATION THAT SPANS ACROSS MUCH OF THE DEEP SOUTH AND
TENNESSEE VALLEY. LATEST 02Z/SUN RADAR MOSAIC SHOWS LEADING EDGE
OF PRECIPITATION SHIELD EXTENDING FROM CENTRAL KY IN TO EXTREME
SRN WV/SW VA. CLOSED UPR LEVEL 50HPA LOW CENTER AT 00Z/SUN OVER
TX/OK BORDER WILL LIFT OUT TO THE NORTHEAST AND OPEN INTO MORE OF
AN OPEN WAVE AS IT CROSSES THE MID ATLANTIC REGION SUN AFTERNOON.
PWAT VALUES PROGGED ACROSS THE REGION PEAK OUT AROUND 1.2 TO 1.3
INCHES...WHICH IS +2 STND DEVIATIONS ABOVE NORMAL. HOWEVER SYSTEM
IS MOVING QUICKLY...AND MAX RAINFALL EXPECTED TO BE BETWEEN 1.25
TO 1.50 INCHES. NO FLOODING CONCERNS WITH THIS SYSTEM.
AND BECAUSE AIRMASS IS SO MILD...WITH NOT A LICK OF COLD AIR IN
SIGHT...THIS EVENT WILL BE ALL RAIN...WITH SFC TEMPS REMAINING
ABOVE FREEZING.
ALL MODEL GUIDANCE FROM 12/18Z NCEP RUNS AND LATEST 21Z/SREF ARE
IN PRETTY GOOD AGREEMENT WITH HANDLING TRACK OF THIS THE LOW
NORTHEAST TO A POSITION NEAR THE GA/SC LINE AT 12Z/SUN...TO SE VA
BY 18Z/SUN AND OFF THE NJ/NY COAST BY 00Z/MON.
BUMPED UP TIMING SLIGHTLY OF ONSET OF PRECIPITATION FOR THE GRIDS
THIS EVENING AS RADAR TRENDS...ALONG WITH LATEST HRRR HIGH RES
MODEL GUIDANCE SHOWS SLIGHTLY FASTER ONSET THAN PREVIOUS FORECAST
HAD.
IN SUMMARY...RAIN WILL OVERSPREAD THE REGION FROM SW TO NE FROM
06Z THROUGH 12Z...THEN CONTINUE MOST OF THE DAY ON SUN...BEFORE
ENDING BY LATER AFTERNOON FROM SW TO NE. OVERALL RAINFALL AMOUNTS
WILL AVERAGE BETWEEN THREE-QUARTERS TO ONE INCH...WITH LOCAL MAX
AMOUNTS UP TO 1.5 INCHES.
&&
.SHORT TERM /SUNDAY NIGHT THROUGH TUESDAY NIGHT/
SUN NIGHT...AS LOW DEEPENS OFF NEW ENGLAND COAST...NW FLOW BEGINS.
COLDER 85H TEMPS BELOW ZERO...WILL HELP CHANGE UPSLOPE PRECIP INTO
ALL SNOW SUNDAY NIGHT. ELSEWHERE...CLEARING AND DRYING TAKE PLACE.
MON AND MON NIGHT...THEN WEAK AREA OF SURFACE HIGH PRES BUILDS
ACROSS THE REGION MON NIGHT. UPSLOPE SNOW SHOWER ACTIVITY WILL
CEASE BY LATE AFTERNOON ON MON.
TUE AND TUE NIGHT...A WEAK WAVE OF LOW PRES PASSES BY TO THE SOUTH
ON TUE. TEMPS ALOFT CERTAINLY COLD ENUF FOR FROZEN PRECIP...BUT
18Z RUNS OF GFS/NAM SUPPRESS MOISTURE TO THE SOUTH...BUT WILL KEEP
THE LOW CHANCE POPS ALONG THE SRN TIER OF COUNTIES FOR NOW.
COLDER HIGH PRES BUILDS IN LATE TUE NIGHT ACROSS THE REGION
BRINGING DRY AND COLDER CONDITIONS FOR NEW YEARS EVE.
PREV LONG TERM DISCUSSION FOLLOWS...
&&
.LONG TERM /WEDNESDAY THROUGH SATURDAY/...
SHORTWAVE DEPARTS TO THE EAST TUESDAY MORNING. WEAK RIDGING AT THE
SURFACE AND ALOFT MOVES ACROSS TUESDAY INTO TUESDAY NIGHT AS COLD
HIGH PRESSURE BUILDS TO THE NORTH.
MAIN FOCUS IN THE LONG TERM CONTINUES TO BE POTENTIAL FOR LOW
PRESSURE SOME TIME BETWEEN LATE WEDNESDAY AND FRIDAY. MODELS ARE IN
SOMEWHAT BETTER AGREEMENT THAN AT THIS TIME YESTERDAY AS MOST
NOW DEPICT A DIGGING TROUGH. BUT THE TIMING AND STRENGTH OF THE
TROUGH STILL DIFFER GREATLY FROM MODEL TO MODEL AND RUN TO RUN.
GENERALLY STUCK TO WPC GUIDANCE...BUT POTENTIAL EXISTS FOR SOME
WINTRY PRECIP WITH AMPLE ARCTIC AIR NEARBY.
&&
.AVIATION /02Z SUNDAY THROUGH THURSDAY/...
LOW PRES OVER FL PANHANDLE AT 01Z/SUN WILL MOVE NE TO POSITION
OVER SE VA/18Z/SUN AND OFF DELMARVA SHORE 21Z/SUN...TO OFF NJ/NY
CSTL AREAS 00Z/MON. RAIN WILL OVERSPREAD REGION LATE TONIGHT AND
CONTINUE THROUGH MID-LATE AFTERNOON SUN. VFR CIGS/VSBYS CURRENTLY
WILL DROP TO MVFR AND THEN IFR EARLY SUN MORNING BETWEEN 10-15Z.
VFR IN NW FLOW TUE AM-WED AM...THEN LOWER CIGS/VSBYS POSSIBLE IN NE
FLOW DEPENDING ON EVOLUTION OF LOW PRESSURE MID-LATE WEEK.
&&
.MARINE...
EXPECT A PERIOD OF SCA CONDITIONS TO DEVELOP SUN EARLY AFTERNOON
ACROSS LOWER BAY/POTOMAC AS LOW PRESSURE MOVES ACROSS THE WATERS
SUNDAY...WITH RAIN EXPECTED. SLY WINDS WILL INCREASE TO SCA
CONDITIONS ACROSS THE WATERS SUNDAY. WINDS WILL VEER TO THE NW ON
THE BACK SIDE OF THE LOW. A SCA MAY BE NEEDED MONDAY AS A COLD
FRONT MOVES THROUGH.
SUB SCA CONDITIONS IN HIGH PRESSURE TUESDAY INTO EARLY
WEDNESDAY...THEN POSSIBLE SCA WINDS/WAVES DEPENDING ON EVOLUTION OF
LOW PRESSURE MID-LATE WEEK.
&&
.LWX WATCHES/WARNINGS/ADVISORIES...
DC...NONE.
MD...NONE.
VA...NONE.
WV...NONE.
MARINE...SMALL CRAFT ADVISORY FROM NOON SUNDAY TO MIDNIGHT EST SUNDAY
NIGHT FOR ANZ530>533-535-536-538>542.
SMALL CRAFT ADVISORY FROM 7 AM SUNDAY TO MIDNIGHT EST SUNDAY
NIGHT FOR ANZ534-537-543.
&&
$$
SYNOPSIS...SMZ
NEAR TERM...SMZ
SHORT TERM...SMZ
LONG TERM...KLW/DFH
AVIATION...SMZ
MARINE...SMZ
AREA FORECAST DISCUSSION
NWS BALTIMORE MD/WASHINGTON DC
932 PM EST SAT DEC 28 2013
.SYNOPSIS...
HIGH PRESSURE WILL REMAIN OVER THE AREA THROUGH THIS AFTERNOON. LOW
PRESSURE WILL MOVE THROUGH THE SOUTHEASTERN CONUS TONIGHT BEFORE
PASSING BY TO OUR EAST SUNDAY AFTERNOON. HIGH PRESSURE WILL BUILD
OVERHEAD MONDAY BEFORE A REINFORCING COLD FRONT MOVES THROUGH
TUESDAY. HIGH PRESSURE WILL DEVELOP TO OUR NORTH DURING THE MIDDLE
AND LATTER PORTIONS OF NEXT WEEK WHILE LOW PRESSURE DEVELOPS TO OUR
SOUTH. UNSETTLED CONDITIONS ARE POSSIBLE DURING THIS TIME.
&&
.NEAR TERM /THROUGH SUNDAY/...
AT 01Z...SURFACE HIGH PRESSURE OVER EASTERN NORTH CAROLINA
EXTENDING EAST OFFSHORE. SWLY FLOW AROUND THE HIGH BROUGHT MILD
CONDITIONS ACROSS THE REGION EARLIER TODAY..AND TEMPS ARE STILL
WELL ABOVE NORMAL SEASONAL HIGHS.
OVERNIGHT AND SUNDAY...AS HIGH RETREATS EAST INTO WRN ATLANTIC...
DEVELOPING SURFACE LOW PRESSURE CENTER THAT AT 00Z WAS NEAR
PENSACOLA FL WILL MOVE NORTHEAST...ATTENDED BY A LARGE AREA OF
PRECIPITATION THAT SPANS ACROSS MUCH OF THE DEEP SOUTH AND
TENNESSEE VALLEY. LATEST 02Z/SUN RADAR MOSAIC SHOWS LEADING EDGE
OF PRECIPITATION SHIELD EXTENDING FROM CENTRAL KY IN TO EXTREME
SRN WV/SW VA. CLOSED UPR LEVEL 50HPA LOW CENTER AT 00Z/SUN OVER
TX/OK BORDER WILL LIFT OUT TO THE NORTHEAST AND OPEN INTO MORE OF
AN OPEN WAVE AS IT CROSSES THE MID ATLANTIC REGION SUN AFTERNOON.
PWAT VALUES PROGGED ACROSS THE REGION PEAK OUT AROUND 1.2 TO 1.3
INCHES...WHICH IS +2 STND DEVIATIONS ABOVE NORMAL. HOWEVER SYSTEM
IS MOVING QUICKLY...AND MAX RAINFALL EXPECTED TO BE BETWEEN 1.25
TO 1.50 INCHES. NO FLOODING CONCERNS WITH THIS SYSTEM.
AND BECAUSE AIRMASS IS SO MILD...WITH NOT A LICK OF COLD AIR IN
SIGHT...THIS EVENT WILL BE ALL RAIN...WITH SFC TEMPS REMAINING
ABOVE FREEZING.
ALL MODEL GUIDANCE FROM 12/18Z NCEP RUNS AND LATEST 21Z/SREF ARE
IN PRETTY GOOD AGREEMENT WITH HANDLING TRACK OF THIS THE LOW
NORTHEAST TO A POSITION NEAR THE GA/SC LINE AT 12Z/SUN...TO SE VA
BY 18Z/SUN AND OFF THE NJ/NY COAST BY 00Z/MON.
BUMPED UP TIMING SLIGHTLY OF ONSET OF PRECIPITATION FOR THE GRIDS
THIS EVENING AS RADAR TRENDS...ALONG WITH LATEST HRRR HIGH RES
MODEL GUIDANCE SHOWS SLIGHTLY FASTER ONSET THAN PREVIOUS FORECAST
HAD.
IN SUMMARY...RAIN WILL OVERSPREAD THE REGION FROM SW TO NE FROM
06Z THROUGH 12Z...THEN CONTINUE MOST OF THE DAY ON SUN...BEFORE
ENDING BY LATER AFTERNOON FROM SW TO NE. OVERALL RAINFALL AMOUNTS
WILL AVERAGE BETWEEN THREE-QUARTERS TO ONE INCH...WITH LOCAL MAX
AMOUNTS UP TO 1.5 INCHES.
&&
.SHORT TERM /SUNDAY NIGHT THROUGH TUESDAY NIGHT/...
SUN NIGHT...AS LOW DEEPENS OFF THE NEW ENGLAND COAST...NW FLOW BEGINS.
COLDER 85H TEMPS BELOW ZERO...WILL HELP CHANGE UPSLOPE PRECIP INTO
ALL SNOW SUNDAY NIGHT. ELSEWHERE...CLEARING AND DRYING TAKE PLACE.
MON AND MON NIGHT...THEN WEAK AREA OF SURFACE HIGH PRES BUILDS
ACROSS THE REGION MON NIGHT. UPSLOPE SNOW SHOWER ACTIVITY WILL
CEASE BY LATE AFTERNOON ON MON.
TUE AND TUE NIGHT...A WEAK WAVE OF LOW PRES PASSES BY TO THE SOUTH
ON TUE. TEMPS ALOFT CERTAINLY COLD ENUF FOR FROZEN PRECIP...BUT
18Z RUNS OF GFS/NAM SUPPRESS MOISTURE TO THE SOUTH...BUT WILL KEEP
THE LOW CHANCE POPS ALONG THE SRN TIER OF COUNTIES FOR NOW.
COLDER HIGH PRES BUILDS IN LATE TUE NIGHT ACROSS THE REGION
BRINGING DRY AND COLDER CONDITIONS FOR NEW YEARS EVE.
PREV LONG TERM DISCUSSION FOLLOWS...
&&
.LONG TERM /WEDNESDAY THROUGH SATURDAY/...
SHORTWAVE DEPARTS TO THE EAST TUESDAY MORNING. WEAK RIDGING AT THE
SURFACE AND ALOFT MOVES ACROSS TUESDAY INTO TUESDAY NIGHT AS COLD
HIGH PRESSURE BUILDS TO THE NORTH.
MAIN FOCUS IN THE LONG TERM CONTINUES TO BE POTENTIAL FOR LOW
PRESSURE SOME TIME BETWEEN LATE WEDNESDAY AND FRIDAY. MODELS ARE IN
SOMEWHAT BETTER AGREEMENT THAN AT THIS TIME YESTERDAY AS MOST
NOW DEPICT A DIGGING TROUGH. BUT THE TIMING AND STRENGTH OF THE
TROUGH STILL DIFFER GREATLY FROM MODEL TO MODEL AND RUN TO RUN.
GENERALLY STUCK TO WPC GUIDANCE...BUT POTENTIAL EXISTS FOR SOME
WINTRY PRECIP WITH AMPLE ARCTIC AIR NEARBY.
&&
.AVIATION /02Z SUNDAY THROUGH THURSDAY/...
LOW PRES OVER FL PANHANDLE AT 01Z/SUN WILL MOVE NE TO POSITION
OVER SE VA/18Z/SUN AND OFF DELMARVA SHORE 21Z/SUN...TO OFF NJ/NY
CSTL AREAS 00Z/MON. RAIN WILL OVERSPREAD REGION LATE TONIGHT AND
CONTINUE THROUGH MID-LATE AFTERNOON SUN. VFR CIGS/VSBYS CURRENTLY
WILL DROP TO MVFR AND THEN IFR EARLY SUN MORNING BETWEEN 10-15Z.
VFR IN NW FLOW TUE AM-WED AM...THEN LOWER CIGS/VSBYS POSSIBLE IN NE
FLOW DEPENDING ON EVOLUTION OF LOW PRESSURE MID-LATE WEEK.
&&
.MARINE...
EXPECT A PERIOD OF SCA CONDITIONS TO DEVELOP SUN EARLY AFTERNOON
ACROSS LOWER BAY/POTOMAC AS LOW PRESSURE MOVES ACROSS THE WATERS
SUNDAY...WITH RAIN EXPECTED. SLY WINDS WILL INCREASE TO SCA
CONDITIONS ACROSS THE WATERS SUNDAY. WINDS WILL VEER TO THE NW ON
THE BACK SIDE OF THE LOW. A SCA MAY BE NEEDED MONDAY AS A COLD
FRONT MOVES THROUGH.
SUB SCA CONDITIONS IN HIGH PRESSURE TUESDAY INTO EARLY
WEDNESDAY...THEN POSSIBLE SCA WINDS/WAVES DEPENDING ON EVOLUTION OF
LOW PRESSURE MID-LATE WEEK.
&&
.LWX WATCHES/WARNINGS/ADVISORIES...
DC...NONE.
MD...NONE.
VA...NONE.
WV...NONE.
MARINE...SMALL CRAFT ADVISORY FROM NOON SUNDAY TO MIDNIGHT EST SUNDAY
NIGHT FOR ANZ530>533-535-536-538>542.
SMALL CRAFT ADVISORY FROM 7 AM SUNDAY TO MIDNIGHT EST SUNDAY
NIGHT FOR ANZ534-537-543.
&&
$$
SYNOPSIS...SMZ
NEAR TERM...SMZ
SHORT TERM...SMZ
LONG TERM...KLW/DFH
AVIATION...SMZ
MARINE...SMZ
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
647 PM EST SAT DEC 28 2013
.SHORT TERM...(THIS EVENING THROUGH SUNDAY)
ISSUED AT 419 PM EST SAT DEC 28 2013
A STALLED FRONTAL BOUNDARY OVER SOUTHERN LAKE SUPERIOR AND NORTHERN
UPPER MICHIGAN HAS LED TO DREARY CONDITIONS FOR MUCH OF UPPER
MICHIGAN TODAY. ON THE PLUS SIDE...TEMPERATURES HAVE BEEN IN THE
LOW TO MID 30S ALONG AND SOUTH OF THE BOUNDARY WHERE THERE HAVE
EVEN BEEN A FEW PEAKS OF SUNSHINE. JUST TO THE NORTH OF THE
BOUNDARY...FAVORABLE EASTERLY FLOW OFF LAKE SUPERIOR HAS LED TO
SOME FZDZ...FOG...AND -SHSN OVER THE KEWEENAW PENINSULA. A SPOTTER
REPORT AROUND 3PM INDICATED A SLIGHT GLAZE IN MOHAWK SHORTLY
AFTER THE VISIBILITY REALLY DROPPED AT KCMX. THINK THAT
FREEZING DRIZZLE WILL REMAIN A THREAT OVER THE NEXT COUPLE OF HOURS
AND EVEN DRIFT SOUTHEAST THROUGH THE EVENING...AS MODELS SHOW A
LACK OF ICE CRYSTALS IN THE CLOUDS BEFORE THE MAIN PRECIPITATION
ARRIVES FROM SOUTHERN CANADA LATE THIS EVENING. ALSO FOR THIS
EVENING...DID ADD SOME PATCHY FOG OVER THE SOUTHEAST PART OF THE
CWA WHERE WINDS WILL BE LIGHT AND THERE HAVE BEEN SOME BREAKS IN
THE CLOUDS.
THE LOW THAT IS CURRENTLY CENTERED IN SOUTH CENTRAL MINNESOTA WILL
CONTINUE EAST TONIGHT AND SUNDAY...BEING CENTERED JUST NORTH OF LAKE
ONTARIO BY 00Z MONDAY. AS THIS LOW SWEEPS EAST...AN AREA OF SNOW
(CURRENTLY IN SOUTHWEST ONTARIO AND ALSO ENTERING NORTHWEST
MINNESOTA) WILL SWEEP ACROSS THE UPPER GREAT LAKES LATE THIS
EVENING THROUGH EARLY SUNDAY MORNING. THE SYNOPTIC SNOW WILL BE
AIDED BY THE RIGHT REAR OF THE 110KT UPPER JET THAT SWEEPS ACROSS
TONIGHT. IN ADDITION...POCKET OF 800-600MB FGEN WILL SLIDE THROUGH
WITH THE 850/700MB TROUGH. THUS...EXPECT A PERIOD OF LIGHT SNOW TO
MOVE ACROSS MUCH OF UPPER MICHIGAN FROM WEST TO EAST. WITH THE BEST
FORCING OVER THE NORTHERN HALF OF THE CWA...EXPECT THE BEST SYNOPTIC
SNOWFALL THERE...WHICH WILL BE AIDED BY LAKE ENHANCEMENT. OVER THE
SOUTHERN HALF...ONLY EXPECT A LIGHT DUSTING TO AN INCH AWAY FROM THE
LAKE SUPERIOR INFLUENCES WITH SNOW RATIOS AROUND NORMAL VALUES OF
13-1.
AS FOR THE LAKE ENHANCEMENT...COLD AIR SURGING IN BEHIND THE LOW
(FALLING FROM RAP ANALYZED VALUES OF 0C FROM WEST-EAST OVER THE
CENTRAL U.P. AT 20Z TO -10 TO -16C AT 12Z SUNDAY AND -23C BY 00Z
MONDAY) WILL LEAD TO LAKE ENHANCEMENT FOR AREAS NEAR LAKE SUPERIOR
AS THE WIND DIRECTIONS BECOME FAVORABLE. THE WINDS WILL BE OUT OF
THE NORTHEAST INITIALLY THIS EVENING OVER WESTERN LAKE
SUPERIOR...BUT AS THE SURFACE/925MB LOW MOVES EAST-NORTHEAST THROUGH
NORTHEAST WISCONSIN AND SOUTH CENTRAL UPPER MICHIGAN TONIGHT...THE
WINDS WILL TRANSITION TO THE NORTH OVERNIGHT...NNW SUNDAY
MORNING...AND THEN NW SUNDAY AFTERNOON. THUS...EXPECT THE INITIAL
ENHANCEMENT TO OCCUR LATE IN THE EVENING OVER THE NE FAVORED
LOCATIONS AND THEN TRANSITION WITH THE WINDS INTO SUNDAY MORNING.
THESE STEADY BACKING WINDS WILL LIKELY BE ONE OF THE LIMITING
FACTORS TO HEAVIER SNOWFALL AMOUNTS. THE SECOND ITEM THAT SHOULD
KEEP SNOWFALL AMOUNTS IN THE LES ADVISORY CATEGORY WILL BE THE SHORT
PERIOD WHEN THE LAKE ENHANCEMENT AND LOW LEVEL TEMPERATURE PROFILE
FALL WITHIN THE DGZ. AT MOST LOCATIONS...IT APPEARS LIKE IT WILL
ONLY OCCUR FOR A 3 TO MAYBE 6HOUR PERIOD. THUS...EVEN THOUGH SNOW
RATIOS WILL QUICKLY RISE TO THE LOWER 20S...THEY WILL QUICKLY FALL
ONCE THE DEEPER MOISTURE DEPARTS AND THE INCREASING COLD AIR MOVES
THE CLOUD OUT OF THE DGZ. FINALLY...GUSTY WINDS MAY LIMIT SNOW
RATIOS FROM GROWING MUCH ABOVE 22/23-1 DURING THE FAVORED
PERIOD...EVEN THOUGH ALL OF THE CLOUD IS WITHIN THE DGZ.
OVERALL...ONLY MADE MINOR TWEAKS TO MUCH OF THE SNOWFALL FORECAST
FOR TONIGHT INTO SUNDAY MORNING...LARGELY WITH HANDLING THE TIMING
OF THE CHANGE OVER TO SNOW FROM NORTHWEST TO SOUTHEAST. THE FAVORED
HIGHER TERRAIN LOCATIONS WILL LIKELY SEE AMOUNTS THROUGH SUNDAY
MORNING IN THE 3-8INCH RANGE...WITH THE GREATEST AMOUNTS OVER THE
HURON MOUNTAINS WITH THE LONGER PERIOD OF FAVORABLE WIND
DIRECTIONS. THAT WOULD BE THE ONLY LOCATIONS WHERE SOME CONCERN OF
NEAR WARNING AMOUNT SNOW WOULD OCCUR...BUT THE SOCIETAL IMPACT WILL
BE LIMITED.
DEEPER MOISTURE FROM THE LOW PULLS OUT QUICKLY FROM WEST TO EAST ON
SUNDAY MORNING AND LEADS TO A TRANSITION TO PURE LAKE EFFECT. WITH
THAT DEEPER MOISTURE DEPARTING...MODELS ARE ONLY SHOWING MOISTURE
AND INVERSION HEIGHTS AROUND 4KFT...BUT WITH LAKE INDUCED
EQUILIBRIUM LEVELS AROUND 5-6KFT...COULD STILL BE SOME STRONGER SNOW
SHOWERS. BUT WITH COLDER AIR CONTINUING TO SURGE IN...MUCH OF THE
CLOUD LAYER WILL MOVE TO THE TOP OF OR ABOVE THE DGZ...WHICH SHOULD
LEAD TO A TRANSITION TO MORE OF COLUMN/PLATES. THEREFORE...WILL
CONTINUE THE IDEA OF LOWERING SNOW RATIOS TO THE HIGH TEENS OR
AROUND 20-1 FROM WEST TO EAST THROUGH THE DAY SUNDAY. THIS SHOULD
LEAD TO LESSER SNOWFALL AMOUNTS IN THE AFTERNOON...WHICH WILL STILL
BE AIDED BY SLOWLY BACKING WINDS TO THE NORTHWEST. OVERALL...HAVE
AFTERNOON AMOUNTS OF 1-2 INCHES IN MOST LOCATIONS...WITH SLIGHTLY
HIGHER VALUES OVER WESTERN ALGER COUNTY. THEREFORE...WILL KEEP LES
ADVISORIES AS IS...ALTHOUGH THE LONG TERM DID MAKE SOME ADJUSTMENTS
TO ALGER TO EXTEND INTO MONDAY. THINK THAT COVERS THE OVERALL IDEA
VERY WELL...SINCE THE NEGATIVES WITH SNOW RATIOS AND BACKING WINDS
SHOULD LIMIT THE POTENTIAL FOR 12HR SNOW AMOUNTS REACHING WARNING
VALUES.
THE COLD AIR SURGING IN WILL LEAD TO FALLING TEMPERATURES STARTING
LATE THIS EVENING OVER THE WEST AND PUSHING ACROSS THE REST OF THE
AREA THROUGH THE NIGHT. OVERNIGHT LOWS FOR TONIGHT AND HIGHS FOR
TOMORROW ARE FAIRLY TRICKY...AS THEY BOTH WILL LIKELY OCCUR DURING
THE TWO HOUR OVERLAP BETWEEN 12-14Z. THUS...TRIED TO FOCUS ON TEMPS
DURING THAT PERIOD TO USE FOR SIMILAR VALUES. WITH THE COLD AIR
CONTINUING TO SURGE IN THROUGH THE DAY ON SUNDAY...EXPECT STEADY OR
SLOWLY FALLING TEMPERATURES THROUGH THE REST OF THE DAY ON
SUNDAY. AFTERNOON VALUES OVER THE WEST WILL BE IN THE LOWER SINGLE
DIGITS ABOVE ZERO AND AROUND 10 DEGREES OVER THE EAST HALF.
FACTORING IN WIND CHILLS...TOMORROW AFTERNOON WILL FEEL ABOUT 50
DEGREES COLDER THAN THIS PAST AFTERNOON.
.LONG TERM...(SUNDAY NIGHT THROUGH SATURDAY)
ISSUED AT 445 PM EST SAT DEC 28 2013
SUN NIGHT INTO MONDAY...ENHANCED LOW-LEVEL CONVERGENCE FROM
DEVELOPING LAND BREEZES AND LAKE-INDUCED TROUGHING WILL FAVOR
ALGER...NRN SCHOOLCRAFT AND LUCE COUNTIES FOR POTENTIAL ADVISORY
CRITERIA SNOWFALL. LES ADVISORIES WILL THEN LIKELY BE NEEDED FOR
THAT PORTION OF THE NE CWA WITH ADDITIONAL ACCUMULATIONS IN THE 3 TO
8 INCH RANGE FROM SUN NIGHT INTO MON MORNING.
WINDS ARE EXPECTED TO STEADILY BACK FROM NNW SUN EVENING TO WRLY BY
EARLY MON AFTERNOON AS SFC HIGH PRESSURE SLIDES FROM THE NRN PLAINS
INTO THE MID MISSISSIPPI VALLEY. THE STEADILY BACKING WINDS WILL
TEND TO SPREAD LES ACCUMULATION AROUND KEEPING MOST AREAS ON THE
LOWER END OF ADVISORY CRITERIA. FAR ERN ALGER AND NRN LUCE WILL BE
THE EXCEPTION WHERE MODELS INDICATE A LONGER PERIOD OF ENHANCED
LOW-LVL CONVERGENCE PARTICULARLY LATE SUN NIGHT INTO MONDAY
WHICH WILL LIKELY PUSH SNOWFALL AMOUNTS ON THE HIGHER END OF
ADVISORY CRITERIA (NEAR 8"). THE VERY DRY COLD ARCTIC AIRMASS ALONG
WITH THE SHORTER FETCH INTO NW UPPER MI WILL MAKE IT LESS FAVORABLE
FOR SIGNIFICANT LES THERE. ADDITIONAL LES WILL BE MORE ON THE ORDER
OF 2 TO LOCALLY 5 INCHES FOR SUN NIGHT INTO MON MORNING SO DO NOT
ANTICIPATE A NEED TO EXTEND LES ADVISORY THERE BEYOND SUNDAY.
HOWEVER...SOME OF THE MESOSCALE MODELS INDICATE THAT LOW-LVL
CONVERGENCE COULD INCREASE AND SOME ENHANCEMENT IS POSSIBLE WITH THE
APPROACH OF THE NEXT CLIPPER SHORTWAVE WHICH SHOULD FOCUS SOME
LOCALLY HEAVIER LES BANDS AND HIGHER ACCUMS BACK OVER THE KEWEENAW
MON AFTERNOON INTO MON EVENING...BUT FOR NOW THIS IS JUST REFLECTED
IN THE FCST GRIDS AND NO HEADLINE IS NEEDED YET.
THE OTHER ISSUE FOR SUNDAY NIGHT INTO MONDAY MORNING WILL BE THE
BITTER COLD ARCTIC AIRMASS SPREADING OVER THE REGION. WITH 8H TEMPS
FROM -22C TO -24C AND WINDS BACKING OFFSHORE TO A MORE WRLY
DIRECTION...THE WESTERN INTERIOR OF THE FCST AREA PARTICULARLY ALONG
THE WI BDR WILL BE UNDER THE GUN FOR ADVISORY CRITERIA WIND CHILLS
OF 25 TO 35 BELOW SUNDAY NIGHT INTO MON MORNING. GIVEN THE FOCUS ON
THE PRESENT LES HEADLINES ELECTED TO HOLD OFF ON WIND CHILL
ADVISORIES FOR NOW...BUT NO DOUBT ONE WILL BE NEEDED FOR A GOOD
PORTION OF THE WESTERN INTERIOR SUN NIGHT INTO MON MORNING.
MON NIGHT-THU...AS MODELS SHOW THE POLAR VORTEX GRADUALLY SHIFTING
FROM HUDSON BAY TO NRN QUEBEC BY TUE EVENING...VERY COLD ARCTIC AIR
WILL DOMINATE THE UPPER GREAT LAKES THROUGH MIDWEEK. WITH 850 MB
TEMPS DROPPING INTO THE -24C TO -29C RANGE...LES WILL PERSIST FOR
LOCATIONS FAVORED BY NW TO WNW FLOW. MODELS IN GOOD AGREEMENT WITH
TIMING OF NEXT CLIPPER SHORTWAVE ACROSS THE AREA MON NIGHT INTO TUE
MORNING. THIS SHORTWAVE WILL REINFORCE ARCTIC AIR WHILE ALSO
SPREADING MID Q-VECT CONV AND DEEPER MOISTURE ACROSS THE REGION.
MODELS INDICATE THIS SHORTWAVE COULD PROVIDE ENHANCEMENT TO LES
WHILE ALSO SHARPENING LAKE-INDUCED TROFFING AND LOW-LVL CONVERGENCE
OVER ERN LAKE SUPERIOR. WHILE THE INFLUX OF COLDER -24 TO -27C 8H
TEMPS BY TUESDAY WILL EVENTUALLY LEAD TO POOR SNOW GROWTH AND
SMALLER SNOWFLAKES...THE WRF-ARW BUFR SNDG FOR GRAND MARAIS MON
NIGHT INTO EARLY TUE SHOWS A SOMEWHAT FAVORABLE SNOW GROWTH PROFILE
WITH THE DGZ INITIALLY INTERSECTING THE BETTER MODEL OMEGA FOCUSED
WITHIN THE CONVECTIVE BOUNDARY LAYER. THIS COULD INITIALLY LEAD TO
HIGHER SLR/S...FLUFFIER SNOW AND GREATER ACCUMULATIONS ESPECIALLY
FOR ERN ALGER AND LUCE COUNTIES. GIVEN THE ABOVE FAVORABLE FACTORS
AND POTENTIAL FOR ENHANCEMENT THERE IS A POTENTIAL FOR HIGH END
ADVISORY LES ACCUMS POSSIBLY PUSHING LES WARNING AMTS MON NIGHT INTO
TUE MORNING FOR ERN ALGER AND LUCE COUNTIES. AFTER TUESDAY...MODELS NOT
INDICATING ANY DISCERNIBLE CLIPPER SHORTWAVES FOR MIDWEEK AS 850 MB
TEMPS GENERALLY REMAIN IN THE -22 TO -26C RANGE. THE COLDER AIRMASS
WILL GENERALLY FAVOR SMALL SNOWFLAKES WITH THE ABSENCE OF
ENHANCEMENT/DEEPER MOISTURE WHICH WILL LIMIT OVERALL ACCUMULATIONS
BUT STILL LEAD TO LOW VISIBILITIES. OUTSIDE OF THE LES...SEVERE WIND
CHILLS CAN BE EXPECTED AT TIMES AS VALUES DROP INTO THE -20 TO -35
RANGE...MAINLY IN THE NIGHTTIME AND MORNING HRS.
MODELS SHOW SIGNS OF TRENDING TOWARD LESS AMPLIFIED PATTERN BY THE
END OF THE WEEK WITH WAA DEVELOPING BY FRI. AS SFC HIGH PRESSURE
SLIDES EAST LATE IN THE WEEK...BOTH THE ECMWF AND GFS DEVELOP AREA
OF LIGHT SNOW IN REGION OF WAA/ISENTROPIC ASCENT AHEAD OF A SHRTWV
MOVING DOWN FM NW ONTARIO. THIS SNOW LOOKS TO SPREAD INTO UPPER MI
LATE FRI OR FRI NIGHT. AS SYSTEM SNOW TAPERS OFF EARLY SAT...LIGHT
LES COULD DEVELOP LATE IN THE DAY AS WINDS SHIFT NORTHERLY BEHIND
FRONTAL PASSAGE.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z SUNDAY EVENING)
ISSUED AT 646 PM EST SAT DEC 28 2013
EXPECT A PERIOD OF -FZDZ MIXED WITH SN AND IFR CONDITIONS EARLY IN
THE FCST PERIOD TO GIVE WAY TO SOME MDT SN/BLSN/LIFR WX BY MIDNGT AS
A GUSTY NNE WIND DVLPS TO THE N OF A LO PRES CENTER PASSING THRU WI.
THE ARRIVAL OF DRIER AIR ALF WL CAUSE THE HEAVIER SN TO DIMINISH BY
SUNRISE ON SUN. IN CONCERT WITH DIMINISHING WINDS/BLSN WITH THE
APRCH OF HI PRES...CONDITIONS SHOULD IMPROVE TO MVFR BY EARLY AFTN
AND EVEN TO VFR AT SAW BY LATER IN THE DAY AS THE FLOW BACKS TO A
DOWNSLOPE NW DIRECTION FOR THAT LOCATION.
&&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 419 PM EST SAT DEC 28 2013
WINDS TO STAY LIGHT UNTIL SFC LOW BRINGS TIGHTENING PRESSURE
GRADIENT TO WESTERN LAKE SUPERIOR THIS AFTERNOON. BY LATE
AFTERNOON...WILL SEE FREQUENT GALE FORCE GUSTS OVER WESTERN LAKE
SUPERIOR WITH NE GALES EXPECTED BY THE EVENING. AS THE SFC LOW
PASSES TO THE SE OF THE AREA OVERNIGHT...NORTH WINDS TO GRADUALLY
RELAX. MUCH COLDER AIR ARRIVING TONIGHT WILL PRODUCE HEAVY FREEZING
SPRAY AS WELL. WINDS GO BELOW 25 KNOTS SUNDAY AFTERNOON AND BELOW 20
KNOTS BY MONDAY AFTERNOON. WINDS REMAIN BELOW 20 KNOTS THROUGH THE
REMAINDER OF THE FORECAST.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
LAKE EFFECT SNOW ADVISORY FROM 10 PM THIS EVENING TO 7 PM EST
SUNDAY FOR MIZ004-005-084.
LAKE EFFECT SNOW ADVISORY FROM 1 PM SUNDAY TO 7 AM EST MONDAY
FOR MIZ085.
LAKE EFFECT SNOW ADVISORY UNTIL 7 PM EST /6 PM CST/ SUNDAY FOR
MIZ001>003-009.
LAKE EFFECT SNOW ADVISORY FROM 1 AM SUNDAY TO 1 PM EST MONDAY
FOR MIZ006.
LAKE EFFECT SNOW ADVISORY FROM 7 PM SUNDAY TO 1 PM EST MONDAY
FOR MIZ007.
LAKE SUPERIOR...
HEAVY FREEZING SPRAY WARNING FROM 1 AM SUNDAY TO 1 AM EST
WEDNESDAY FOR LSZ265>267.
GALE WARNING UNTIL 7 AM EST /6 AM CST/ SUNDAY FOR LSZ162-263>266.
HEAVY FREEZING SPRAY WARNING UNTIL 1 AM EST /MIDNIGHT CST/
MONDAY FOR LSZ162-263-264.
HEAVY FREEZING SPRAY WARNING FROM 1 AM SUNDAY TO 6 PM EST MONDAY
FOR LSZ248>251.
HEAVY FREEZING SPRAY WARNING UNTIL 7 PM EST /6 PM CST/ SUNDAY
FOR LSZ240>247.
GALE WARNING UNTIL 5 AM EST /4 AM CST/ SUNDAY FOR LSZ241.
GALE WARNING UNTIL 5 AM EST /4 AM CST/ SUNDAY FOR LSZ240.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...SRF
LONG TERM...VOSS
AVIATION...KC
MARINE...SRF
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
508 PM EST FRI DEC 27 2013
.SHORT TERM...(THIS EVENING THROUGH SATURDAY)
ISSUED AT 507 PM EST FRI DEC 27 2013
12Z RAOBS/LATEST WV IMAGERY AND RUC ANALYSIS SHOW NW FLOW ALF ACROSS
THE UPR GRT LKS BTWN TROFFING OVER ERN NAMERICA AND UPR RDG IN THE
ROCKIES. SW FLOW/ISENTROPIC ASCENT IN ADVANCE OF SHRTWV DIGGING SEWD
THRU ONTARIO HAS BROUGHT LOTS OF CLDS TO THE CWA. RADAR/SFC OBS
INDICATE SN IS FALLING OVER LK SUP CLOSER TO THE SHARPER ISENTROPIC
ASCENT/SHRTWV AND ACCOMPANYING SFC LO TRACK...BUT DRY WEDGE BTWN
H8-7 SHOWN ON THE 12Z INL RAOB HAS LIMITED THE COVERAGE OF THE SN
FARTHER SW OVER THE LAND CWA. OTRW...SSW LLVL FLOW HAS ADVECTED
WARMER AIR INTO UPR MI...WITH TEMPS THIS AFTN APRCHG ABV 32 AT IWD.
BUT TEMPS REMAIN WELL BLO FRZG OVER THE INTERIOR CENTRAL. THERE IS
SOME CLRG IN MN EXTENDING TOWARD WRN UPR MI WHERE THE LLVL WARMING
HAS BEEN MOST AGGRESSIVE ON THE SRN FLANK OF THE SFC LO SHIFTING
ESEWD NEAR THE MN/CNDN BORDER AND IN ADVANCE OF AN ATTENDANT LO PRES
TROF EXTENDING SWWD INTO THE ERN DAKOTAS. BUT MORE LO CLDS AND SOME
GUSTY NW WINDS FOLLOW THIS TROF FM NDAKOTA INTO MANITOBA/ADJOINING
ONTARIO. FARTHER TO THE W...A STRONG SHRTWV IS MOVING OVER THE WRN
UPR RDG INTO THE PAC NW/BRITISH COLUMBA.
MAIN FCST CONCERNS IN THE SHORT TERM ARE CLD TRENDS/POPS THIS AFTN
RELATED TO THE ONGOING WAD AHEAD OF THE APRCHG DISTURBANCE AND THEN
THE CHC FOR SOME -SN OR EVEN FREEZING DRIZZLE TNGT INTO SAT
FOLLOWING THE TROF PASSAGE.
LATE THIS AFTN/TNGT...BEST CHC FOR SOME WAD SN LATE THIS AFTN INTO
THE EVNG WL BE OVER THE ERN CWA WHERE GUIDANCE SHOWS DEEPER
SATURATION UNDER THE SHARPER ISENROPIC ASCENT DEEPER INTO THE
RETREATING COLD AIR. THE CHC POPS OVER THE ERN CWA WL SHIFT TO THE E
THIS EVNG FOLLOWING PASSAGE OF DISTURBANCE AND END OF WAD/ISENTROPIC
ASCENT. ALTHOUGH THERE WL BE SOME CLRG OVER THE W LATE THIS AFTN
INTO EARLY EVNG PER CURRENT OBS/STLT TRENDS...PASSAGE OF SFC LO PRES
TROF WL BRING A RETURN OF MORE LLVL MSTR/LO CLDS. SOME OF THE MODELS
ALSO GENERATE LGT PCPN OVER MAINLY THE W IN AREAS WHERE WNW FLOW WL
UPSLOPE DESPITE PRESENCE OF LARGER SCALE QVECTOR DVGC/DNVA/WEAK CAD
FOLLOWING THE SHRTWV. FCST SDNGS INDICATE THE MSTR WL BE CONFINED TO
THE LOWEST FEW THOUSAND FEET AND WELL BLO THE DGZ AS INCOMING
AIRMASS IS MARITIME POLAR IN ORIGIN. IN FACT...H85 TEMPS ARE FCST TO
FALL NO LOWER THAN -6C TO -8C EVEN OVER THE TIP OF THE KEWEENAW THRU
12Z SAT...TOO WARM FOR ANY LES. SO RETAINED MENTION OF SOME FREEZING
DRIZZLE AS WELL AS FINE SN/FLURRIES IN THESE UPSLOPE AREAS. AS THE
FLOW AND UPSLOPE WIND COMPONENT DIMINISHES LATE WITH ARRIVAL OF
WEAKER PRES GRADIENT...ANY -FZDZ MAY DIMINISH A BIT AS WELL. WEAKENS
DOWNSLOPE NATURE OF THE EXPECTED LLVL FLOW IN THE WAKE OF THE TROF
MAY RESULT IN SOME CLRG OVER THE SCENTRAL. OVERNGT TEMPS WL BE MUCH
WARMER THAN ON RECENT NGTS GIVEN EXPECTED CLD COVER/MODEST CHILL OF
AIRMASS. THE LOWEST MIN TEMPS ARE MOST LIKELY OVER THE SCENTRAL
WHERE MORE SUSTAINED CLRG SHUD ALLOW FOR A SHARPER TEMP DROP. SOME
FOG MAY DVLP IN THESE AREAS AS WELL WITH RELATIVELY HI SFC DEWPTS.
SAT...FOCUS SHIFTS TO TIMING/IMPACT OF SHRTWV NOW MOVING INTO THE
PAC NW AND ARPCH OF COLD FNT FM THE N. GUIDANCE SHOWS SFC COLD FNT
AND ACCOMPANYING BAND OF H85-7 FGEN SHIFTING SLOWLY S INTO THE NRN
CWA BY EARLY AFTN AS THE FLOW TURNS MORE TO THE NNE WELL TO THE S OF
COLD HI PRES BLDG THRU CENTRAL CANADA. SINCE THE MSTR IS FCST TO
STILL BE RELATIVELY SHALLOW...FREEZING DRIZZLE AS WELL AS SOME LGT
SN/FLURRIES MAY BE THE PTYPE...ESPECIALLY IN UPSLOPE AREAS NEAR LK
SUP. BUT AS THE SHRTWV TO THE W APRCHS LATER IN THE DAY...VIGOROUS
H85-5 QVECTOR CNVGC AND SOME UPR DVGC IN RRQ OF 140KT H3 JET MAX
STREAKING ACRS ONTARIO WL BRING A RETURN OF DEEPER MSTR/HIER POPS
OVER AT LEAST THE NRN TIER. EXPECT THE HIEST TEMPS AOA FRZG OVER THE
SCENTRAL...WHERE THE FNT WL NOT LIKELY PASS UNTIL AFTER 00Z SUN.
.LONG TERM...(SATURDAY NIGHT THROUGH FRIDAY)
ISSUED AT 507 PM EST FRI DEC 27 2013
SAT NIGHT...UPPER LEVEL DIV WITH THE RIGHT ENTRANCE OF THE 130KT
250-300 MB JET THROUGH NRN ONTARIO/WRN QUEBEC AND ASSOCIATED 700
MB FGEN WILL RESULT IN STRONG ENOUGH UPWARD MOTION TO SUPPORT A BAND
OF SNOW FROM NRN MN THROUGH THE NRN LAKES. THE 12Z MODELS ARE IN
GENERAL AGREEMENT WITH POSITION OF HEAVIER PCPN BAND THROUGH NRN
UPPER MI. CONSENSUS QPF AMOUNTS OF 0.15-0.30 WITH SLR VALUES IN THE
15/1 RANGE WOULD GIVE SYNOPTIC SNOW AMOUNTS OF 1 TO LOCALLY 4 INCHES
...GREATEST NORTH. IN ADDITION...CYCLONIC NE TO NNE FLOW INTO NRN
UPPER MI WILL ALSO BRING ADDITIONAL LAKE ENHANCED SNOW AMOUNTS.
SINCE SLR VALUES ONLY CLIMB NEAR 20/1 LATE SAT NIGHT WITH THE
ARRIVAL OF THE COLDER AIR...ADDITIONAL ENHANCEMENT AMOUNTS IN THE 1
TO 4 INCH RANGE WOULD KEEP OVERALL TOTAL GENERALLY IN THE ADVISORY
RANGE OR BELOW 8 INCHES. BELIEVE ONLY A FEW LOCATIONS OVER THE HURON
MTNS COULD APPROACH WARNING CRITERIA OF 8 INCHES DUE TO MORE
PROLONGED FAVORABLE UPSLOPE NE FLOW. IN ADDITION...NRLY WINDS
GUSTING TO 25 TO 30 MPH IN OPEN AREAS NEAR THE LAKE SHORES WILL
PRODUCE BLOWING AND DRIFTING SNOW.
SUN...A TRANSITION FROM LAKE ENHANCED TO PURE LES IS EXPECTED AS THE
DEEPER MOISTURE AND MID-LVL Q-VECT CONV DEPARTS E WITH MOVEMENT OF
LOW PRESSURE SYSTEM. 850 MB TEMPS DROPPING INTO THE -19C TO -22C
RANGE BY 18Z AS 850-700 MB MOISTURE STILL LINGERS OVER AREA WILL
FAVOR CONTINUED MODERATE TO HEAVY LES...ESPECIALLY FOR LOCATIONS
FAVORED BY NRLY UPSLOPE FLOW. EXPECT LES RATES TO GRADUALLY DIMINISH
IN THE AFTERNOON AS WINDS BACK AND INVERSION HEIGHTS DROP TO AROUND
5K FT. WITH EXPECTED SNOWFALL AMOUNTS GENERALLY IN HIGH END OF THE
ADVISORY RANGE...WILL CONTINUE WITH A SPS TO HIGHLIGHT THE POTENTIAL
FOR SIGNIFICANT SNOWFALL. EXPECT THE GREATEST TOTAL ACCUMULATIONS
FROM IRONWOOD THROUGH THE PORCUPINE MOUNTAINS TO ROCKLAND IN THE
WEST AND FROM HERMAN THROUGH THE HURON MOUNTAINS TO NEGAUNEE OVER
THE NORTH CENTRAL. A FEW FAVORED HIGHER TERRAIN LOCATIONS COULD
APPROACH 10 TO 12 INCHES THROUGH THE EVENT.
SUN NIGHT...ENHANCED LOW-LEVEL CONVERGENCE FROM DEVELOPING LAND
BREEZES COULD FAVOR AREAS EAST OF MQT FOR ADDITIONAL MODERATE LES
ACCUMULATION. NAM BUFR SNDGS SHOW FAVORABLE PLACEMENT OF DGZ WITHIN
BEST MODEL OMEGA OF CONVECTIVE BOUNDARY LAYER SO GOOD SNOW GROWTH
AND FLUFFY LES ACCUMULATION EXPECTED. WOULD NOT BE SURPRISED TO SEE
ADVISORY SNOWFALL OF 4 INCHES OR MORE OVER PORTIONS OF ERN
ALGER...NRN SCHOOLCRAFT AND NW LUCE COUNTY WHERE MODELS SHOW BEST
LOW-LVL CONVERGENCE.
MON-WED...AS THE POLAR VORTEX GRADUALLY SHIFTS FROM HUDSON BAY TO
NRN QUEBEC...VERY COLD ARCTIC AIR WILL DOMINATE THE WRN GREAT LAKES.
WITH 850 MB TEMPS DROPPING INTO THE -25C TO -29C RANGE...LES WILL
PERSIST FOR LOCATIONS FAVORED BY NW TO W FLOW. AS TO BE EXPECTED
MODELS STILL SHOWING DIFFERENCES WITH TIMING OF SHORTWAVES MOVING
THROUGH THE REGION AND THUS ACCOMPANYING WIND SHIFTS. THERE MAY
BE PERIODS WHERE THE WINDS ARE LIGHT ENOUGH FOR LAKE INDUCED
TROUGHING TO DOMINATE THE LOW LEVEL FLOW. THE COLD AIRMASS WILL ALSO
FAVOR SMALL SNOWFLAKES THAT WILL LIMIT OVERALL ACCUMULATIONS BUT
STILL LEAD TO LOW VISIBILITIES. OUTSIDE OF THE LES...SEVERE WIND
CHILLS AT TIMES ASE VALUES DROP INTO THE -20 TO -35 RANGE.
THU AND FRI...MODELS SHOW SIGNS OF TRENDING TOWARD LESS AMPLIFIED
PATTERN BY THE END OF THE WEEK WITH WAA DEVELOPING. SFC HIGH
PRESSURE OVER THE REGION SHOULD ENSURE MOSTLY DRY CONDITIONS ON
THURSDAY...EXCEPT FOR SOME LINGERING LIGHT WEST FLOW LES ALONG LAKE
SUPERIOR. EXPECT HIGH TEMPS THU TO REBOUND BACK INTO THE DOUBLE
DIGITS ABOVE ZERO. STRONGER WAA ON FRIDAY AHEAD OF THE NEXT
ADVANCING CLIPPER SYSTEM MAY ALLOW FOR HIGH TEMPS TO CLIMB BACK INTO
THE 20S ESPECIALLY OVER THE EAST HALF OF THE FCST AREA. BOTH THE
ECMWF AND GFS DEVELOP AREA OF LIGHT SNOW NORTH OF LAKE SUPERIOR IN
WAA/ISENTROPIC ASCENT AND SPREAD THIS SNOW ACROSS MAINLY THE EASTERN
AND NORTH CENTRAL FCST AREA. WILL INCLUDE HIGHER CHC POPS IN FRI
FCST FOR THIS SNOW POTENTIAL.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SATURDAY AFTERNOON)
ISSUED AT 1223 PM EST FRI DEC 27 2013
TRICKY AVIATION FORECAST THIS AFTERNOON WITH STRONG SSW WIND IN
ADVANCE OF DISTURBANCE DROPPING SEWD TOWARD THE UPR GRT LKS. PLENTY
OF LO CLDS JUST TO THE S OF UPR MI...BUT DOWNSLOPING HAS CAUSED
THESE CLDS TO BREAK UP AT TIMES. INCLUDED TEMPO GROUPS FOR THE FIRST
COUPLE OF HRS TO SHOW MVFR CIGS GIVEN POTENTIAL FOR SOME OF THESE
CLDS TO SURVIVE INTO THE TAF SITES...ESPECIALLY EARLY IN THE FCST
PERIOD BEFORE WARMER AIR ARRIVES. EXPECT GUSTY WINDS AT TIMES AT THE
MORE EXPOSED IWD/SAW LOCATIONS...BUT INCLUDED LLWS FOR THE MORE
SHELTERED CMX SITE. THE PASSAGE OF A LO PRES TROF TNGT FOLLOWING THE
PASSAGE OF THE DISTURBANCE SHOULD RESULT IN A WSHFT TO THE WNW AND
THE ARRIVAL OF SOME SHALLOW MSTR. MVFR CONDITIONS WL BE THE RESULT
EXCEPT AT CMX...WHERE MORE PRONOUNCED UPSLOPE COMPONENT WL BRING
ABOUT IFR CONDITIONS. THERE COULD ALSO BE SOME FLURRIES AND -FZDZ AT
IWD AND ESPECIALLY CMX. THESE LOWER CONDITIONS WL PERSIST THRU SAT
MRNG WITH THE ARRIVAL OF A COLD FNT.
&&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 507 PM EST FRI DEC 27 2013
EXPECT SW WINDS UP TO 30 KTS AND SOME FREEZING SPRAY THIS EVENING TO
DIMINISH WITH ARRIVAL OF WEAKER PRES GRADIENT ACCOMPANYING A LO PRES
PASSAGE. STRONGER N WINDS AND SOME FREEZING SPRAY WILL REDEVELOP ON
SAT FOLLOWING THE PASSAGE OF ANOTHER COLD FRONT AND AS ARCTIC AIR
SURGES S IN ADVANCE OF HI PRES BUILDING INTO SCENTRAL CANADA. AS
ARCTIC AIR FLOWS S INTO THE AREA BEHIND FRONT AND NE GRADIENT
TIGHTENS BEHIND LOW PASSING TO SOUTH LOOK FOR A PERIOD OF GALES TO
DEVELOP OVER THE WEST AND NCNTRL SAT NIGHT SO HAVE ISSUED A GALE
WATCH FOR THIS POTENTIAL. OTHERWISE NE WINDS TO 30KT WILL BE COMMON
SAT NIGHT FOR THE REST OF THE LAKE BACKING TO THE NORTH ON SUNDAY.
HEAVY FREEZING SPRAY IS STILL EXPECTED OVER MUCH OF THE LAKE SAT
NIGHT INTO MONDAY. IT APPEARS THAT THE ARCTIC AIR WILL SETTLE INTO
THE UPPER LAKES FOR AN EXTENDED STAY MUCH OF NEXT WEEK...ALTHOUGH NO
GALES APPEAR EVIDENT AT THIS POINT.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
HEAVY FREEZING SPRAY WARNING FROM 1 AM SUNDAY TO 7 AM EST MONDAY
FOR LSZ265-267.
HEAVY FREEZING SPRAY WARNING FROM 1 AM SUNDAY TO 7 PM EST MONDAY
FOR LSZ266.
GALE WATCH FROM SATURDAY EVENING THROUGH SUNDAY MORNING FOR
LSZ162-263-264.
HEAVY FREEZING SPRAY WARNING FROM 7 PM EST /6 PM CST/ SATURDAY
TO 1 AM EST /MIDNIGHT CST/ MONDAY FOR LSZ162-263-264.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...KC
LONG TERM...VOSS
AVIATION...KC
MARINE...VOSS/KC
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
1144 PM EST THU DEC 26 2013
.SHORT TERM...(THIS EVENING THROUGH FRIDAY)
ISSUED AT 511 PM EST THU DEC 26 2013
12Z RAOBS/LATEST WV IMAGERY AND RUC ANALYSIS SHOW UPR TROF OVER ERN
AMERICA DOWNSTREAM OF MEAN RDG OVER THE W. WNW LLVL FLOW OF H85
TEMPS AS LO AS -18C TO -20C E OF SFC RDG AXIS EXTENDING FM NE MN
INTO WI IS BRINGING MORE LES TO THE FAVORED SN BELTS. INVRN BASE
NEAR H8 AS SHOWN ON THE 12Z APX RAOB HAS SUPPORTED SOME LOCALLY HVY
SHSN OVER THE KEWEENAW AND IN ALGER COUNTY...BUT THE 12Z INL RAOB
CLOSER TO THE INCOMING SFC HI PRES RDG SHOWS A MUCH LOWER INVRN BASE
NEAR H9. SHRWV EMBEDDED IN THE NW FLOW ALF IS DROPPING SEWD THRU MN
THIS AFTN ACCOMPANIED BY BAND OF H7-3 QVECTOR CNVGC THAT IS
IMPACTING UPR MI ON THE CYC SIDE OF THIS FEATURE...BUT THE MID LVLS
ARE SO DRY WITH H85-5 QVECTOR DVGC THESE DYNAMICS APPEAR TO BE
HAVING LTL IMPACT ON THE LES. IN FACT...THE MQT VWP INDICATES THE
SUBSIDENCE INVRN HAS ACTUALLY LOWERED. CLDS ON THE NE EDGE OF THE
DEEPER MSTR ARE BRUSHING THE WI BORDER COUNTIES. BUT VSBL STLT
IMAGERY INDICATES A HEAVIER BAND OF LES PERSISTS OVER NCENTRAL
HOUGHTON COUNTY...WITH VSYBS REPORTED AS LO AS 1/2SM AT CMX. A
HEAVIER SN BAND ALSO IMPACTED ALGER COUNTY NEAR MELSTRAND EARLIER...
BUT THE WINDS HAVE BACKED ENUF TO SHIFT THIS SHSN N THRU ERN ALGER
COUNTY. FARTHER TO THE W...YET ANOTHER SHRTWV IS RIDING THRU BRITISH
COLUMBIA OVER THE WRN RDG.
MAIN FCST CONCERNS IN THE SHORT TERM ARE FOCUSED ON LES TRENDS THRU
THIS EVNG AND GOING HEADLINES.
TNGT...SHRTWV SLIDING SEWD THRU MN IS PROGGED TO REACH THE LOWER GRT
LKS THIS EVNG...LEAVING SHARP DEEP LYR QVECTOR DVGC IN ITS WAKE. IN
RESPONSE TO THE STRONG ACCOMPANYING SUBSIDENCE...INVRN BASES ARE
PROGGED TO FALL AOB 3K FT THRU THE NGT. AS THE SFC HI PRES RDG
SLIDES TO THE SE...THE LLVL FLOW IS PROGGED TO BACK SLOWLY TO THE
WSW BY 12Z FRI. THE COMBINATION OF SINKING INVRN BASE/SHIFTING WINDS
SHOULD DIMINISH THE LES THRU THE NGT...WITH THE LES LINGERING
LONGEST OVER THE N HALF OF THE KEWEENAW AND OVER THE E NEAR LK SUP
FM GRAND MARAIS TOWARD WHITEFISH POINT. OVERALL...GOING HEADLINE
EXPIRATIONS APPEAR ON TRACK...BUT THE EVNG SHIFT MAY BE ABLE TO CANX
THE ALGER/LUCE ADVY EARLY IF INCRSG LAND BREEZE CNVGC DOES NOT
INTENSIFY THE LES NEAR THE SHORE. AS FOR MIN TEMPS...EXPECT THE
LOWEST READINGS OVER THE INTERIOR SCENTRAL...WHERE SKIES WL BE MOCLR
AND WINDS LIGHTER FOR A GOOD PORTION OF THE NGT. A STRONGER S WIND
DVLPG OVER THE WRN ZNS BTWN THE DEPARTING SFC HI AND FALLING MSLP
OVER THE PLAINS AHEAD OF SHRTWV NOW TOPPING THE WRN RDG WL LIMIT THE
DIURNAL FALL THERE DESPITE A PERIOD OF MOCLR-PCLDY SKIES.
FRI...SHRTWV NOW RIDING OVER THE WRN RDG IS PROGGED TO SLIDE ESEWD
THRU ONTARIO/THE UPR LKS ON FRI AFTN...ACCOMPANIED BY A SFC LO
MOVING OVER SRN ONTARIO. WITH SOME FAIRLY SHARP ISENTROPIC ASCENT
SHOWN ON THE 290-295K SFCS /H65-8/...EXPECT INCRSG MID CLDS...
ESPECIALLY OVER THE NE HALF OF THE CWA UNDER THE SHARPER ASCENT.
THESE DYNAMICS/MODEL QPF ALSO SUPPORT GOING CHC POPS OVER THE NE CWA
CLOSER TO THE TRACK OF THE SHRTWV/SFC LO. GIVEN THE INTENSITY OF THE
ISENTROPIC LIFT...SOME H85-7 FGEN...AND THE PERSISTENT CHILL THAT
WOULD SUPPORT BETTER LIFT TO THE SW...SHIFTED THE SW EDGE OF THE
POPS A BIT TO THE SW PER THE SOMEWHAT WETTER GFS/CNDN MODELS. GIVEN
THE HI STABILITY/LLVL COLD AIR...TENDED TOWARD THE LOWER END OF
GUIDANCE FOR MAX TEMPS. EXPECT THE HIEST TEMPS NEAR FRZG OVER THE W
NEAR LK SUP...WHERE STRENGTHENING SSW WIND TO THE S OF PRES FALL
CENTER WL DOWNSLOPE.
.LONG TERM...(FRIDAY NIGHT THROUGH THURSDAY)
ISSUED AT 511 PM EST THU DEC 26 2013
AT THE BEGINNING OF THE LONG TERM...THERE WILL BE A BRIEF WARMUP AS
FLOW TEMPORARILY BECOMES ZONAL ACROSS THE NRN CONUS...ALLOWING
PACIFIC AIR TO SPREAD E. HOWEVER...A REORGANIZING AND EXPANDING
POLAR VORTEX CURRENTLY LOCATED WELL N IN NRN CANADA WILL BE
DEEPENING AS IT DROPS S TO THE VCNTY OF HUDSON BAY OVER THE NEXT 7
DAYS. EARLY NEXT WEEK...A LARGE MASS OF EXTREMELY COLD AIR WILL BE
CENTERED AROUND HUDSON BAY. MEDIUM RANGE MODELS HAVE BEEN FAIRLY
CONSISTENT SHOWING 850MB TEMPS AS LOW AS -35C TO -40C AT THE CORE OF
THE POLAR VORTEX. THE EXPANDING MASS OF ARCTIC AIR WILL SPREAD S
INTO THE GREAT LAKES NEXT WEEK...AND GIVEN THE EXTREME COLD TO THE
N...THERE MAY BE A COUPLE OF SHOTS OF BITTER COLD AIR INTO UPPER MI
DURING THE WEEK. EVOLVING PATTERN WILL NOT BE FAVORABLE FOR MUCH IN
THE WAY OF WIDESPREAD SYNOPTIC SNOWFALL OVER THE NEXT 7 DAYS. AFTER
INITIAL NE-N FLOW MODERATE LAKE EFFECT SNOW EVENT FOR SAT NIGHT INTO
SUNDAY...LES WILL THEN FOCUS OVER THE W TO NW SNOW BELT FOR MUCH OF
NEXT WEEK. LES ON MOST DAYS PROBABLY WON`T BE SIGNIFICANT AS ARCTIC
AIR WILL RESULT IN SMALL SNOWFLAKES. HOWEVER...THE SMALL SNOWFLAKES
WILL BE VERY EFFECTIVE AT REDUCING VISIBILITY. ON THE COLDEST
DAYS...WHITEOUTS WILL PROBABLY BE COMMON WHERE LES OCCURS.
BEGINNING FRI NIGHT...WAA AND 290K ISENTROPIC ASCENT WILL RESULT IN
SOME LINGERING LIGHT SNOW IN THE EVENING OVER MAINLY ERN AND
POSSIBLY OVER THE NW PORTION OF THE CWA BEFORE SNOW ENDS OVERNIGHT
WITH TRANSITION TO ISENTROPIC DESCENT. WILL CONTINUE LOW CHC 30 PCT
POPS FAR EAST WITH SCHC 20 PCT POPS OVER THE KEWEENAW. MIN TEMPS
WILL BE MAINLY IN THE UPPER TEENS TO MID 20S.
WARMER WEATHER WILL CONTINUE INTO SAT AHEAD OF A SHORTWAVE TRACKING
FROM BC/PACIFIC NW INTO THE CANADIAN HIGH PLAINS. MOST LOCATIONS
SHOULD TOP OUT NEAR 30F. HOWEVER...A COLD FRONT DRIFTING S ACROSS
UPPER MI DURING THE DAY SAT WILL HAVE AN INFLUENCE ON MAX TEMPS
DEPENDING ON ITS TIMING. UPPER DIVERGENCE ASSOCIATED WITH THE RIGHT
ENTRANCE OF UPPER JET TO THE N AND NE AND A ZONE OF MIDLEVEL
FRONTOGENESIS WILL SUPPORT A RIBBON OF -SN BEHIND THE SOUTHWARD
SAGGING COLD FRONT. THAT -SN SHOULD SPREAD S ACROSS THE NRN UPPER MI
DURING THE DAY. AS COLD FRONT CONTINUES TO DROP S SAT NIGHT...UPPER
DIVERGENCE/MID LEVEL FRONTOGENESIS AND Q-VECT CONV WILL CONTINUE TO
SUPPORT -SN. SO...EXPECT MOST OF THE FCST AREA TO SEE -SN SAT NIGHT.
LAKE ENHANCEMENT SEEMS LIKELY FOR MOST IF NOT ALL OF NRN UPPER MI
SAT NIGHT INTO SUNDAY AS WINDS SHIFT FROM NE SAT EVENING TO NRLY
LATE SAT NIGHT INTO SUNDAY. MODERATE TO OCCASIONAL HVY SNOW COULD BE
POSSIBLE OVER THE HIGHER TERRAIN OF WEST AND NORTH CENTRAL UPPER MI.
WILL CONTINUE TO HIGHLIGHT THIS SIGNIFICANT SNOW POTENTIAL IN THE
HWO. BEHIND THE FRONT...MUCH COLDER AIR WILL BEGIN TO FLOW S INTO
UPPER MI SAT NIGHT AND ESPECIALLY SUN AS 850MB TEMPS PLUMMET INTO
THE -20 TO -25C RANGE BY SUN AFTERNOON. TEMPS SHOULD SLOWLY FALL
THRU THE DAY ON SUNDAY. EXPECT LINGERING LES INTO SUN NIGHT AND SNOW
COULD BE MODERATE OVER NORTH CENTRAL UPPER MI WITH MODELS INDICATING
PERSISTENT CONVERGENT/CYCLONIC N-NNW FLOW.
PERSISTENT LES WILL THEN SET UP MON/TUE/WED...MOSTLY FOR W TO WNW
WIND FAVORED SNOWBELTS...AS ACRTIC AIR SETTLES OVER THE AREA (850MB
TEMPS GENERALLY IN THE MID TO UPPER -20S C). AT THIS POINT...IT
DOESN`T APPEAR LES ACCUMS WILL BE SIGNIFICANT DUE TO THE ARCTIC AIR
AND CONSEQUENT SMALL SNOWFLAKE SIZE. HOWEVER...IF ANY SHORTWAVES
PROVIDE ENHANCEMENT OR LAND BREEZES FOCUS CONVERGENCE...THERE MAY BE
LOCALLY HVY LES. OTHERWISE...AS PREVIOUSLY MENTIONED...THE SMALL
SNOWFLAKES WILL BE VERY EFFECTIVE AT REDUCING VISIBILITY...SO
WHITEOUTS MAY BE COMMON IN AREAS IMPACTED BY LES EARLY NEXT WEEK.
MAX TEMPS MAY STRUGGLE TO GET ABOVE 0F OVER SOME PORTIONS OF WRN
UPPER MI MON/TUE/WED. MODELS POINTING TOWARD LATE TUE FOR COLDEST
850MB TEMPS ACROSS AREA AROUND -28C. IF SO...SUBZERO HIGH TEMPS
WOULD BE COMMON OVER MUCH OF W AND CNTRL UPPER MI. WIND CHILL VALUES
WILL LIKELY FALL INTO THE ADVY RANGE AT TIMES.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z FRIDAY NIGHT)
ISSUED AT 1144 PM EST THU DEC 26 2013
CMX...EXPECT MVFR CONDITIONS UNTIL MORNING AS LAKE EFFECT SNOW BANDS
DRIFT TO THE NORTH OF THE SITE. VFR WX SHOULD THEN DOMINATE ON FRI
MRNG WITH A DRIER SW FLOW DESPITE A GOOD DEAL OF MID CLD COVER. AS
WINDS TURN TO THE WEST FRI EVENING...MVFR CONDITIONS WITH LAKE
EFFECT SNOW SHOWERS RETURN.
IWD AND SAW...ALTHOUGH SOME MVFR CIGS MAY IMPACT SAW EARLY THIS
MORNING...EXPECT VFR WX FOR MOST OF THIS FCST PERIOD WITH A DRY W-SW
FLOW TO THE NW OF HI PRES MOVING TOWARD THE LOWER GRT LKS. WILL GET
GUSTY AT BOTH SITES LATE FRI MORNING. MVFR CONDITIONS RETURN TO IWD
BY FRI EVENING WITH LAKE EFFECT CLOUDS COMING BACK IN ON WEST WINDS.
&&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 511 PM EST THU DEC 26 2013
EXPECT WNW WINDS 15 TO 25 KTS LATE THIS AFTERNOON TO DIMINISH WITH
PASSAGE OF SFC HI PRES RDG. BUT THE SHARPENING PRES GRADIENT BETWEEN
THE DEPARTING HI AND ANOTHER LO TRACKING THRU SOUTHERN CANADA WILL
CAUSE SW WINDS TO INCREASE UP TO 25 TO 30 KTS ON FRI. EXPECT BRIEF
LULL IN WINDS LATE FRI NIGHT INTO SAT MORNING AS FRONT DRIFTS S
ACROSS THE AREA. THEN AS ARCTIC AIR FLOWS S INTO THE AREA BEHIND
FRONT...NORTH WINDS TO 30KT WILL BE COMMON SAT NIGHT/SUN...AND THERE
COULD BE A PERIOD OF GALES OVER WEST AND CENTRAL LAKE SUPERIOR.
HVY FREEZING SPRAY WILL ALSO RETURN SAT NIGHT AND WILL LIKELY
CONTINUE THRU THE MIDDLE OF NEXT WEEK AS ARCTIC AIR SETTLES INTO THE
UPPER LAKES FOR AN EXTENDED STAY.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
LAKE EFFECT SNOW ADVISORY UNTIL 1 AM EST FRIDAY FOR MIZ001.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...KC
LONG TERM...VOSS
AVIATION...07
MARINE...KC/VOSS
AREA FORECAST DISCUSSION
NWS NORTH PLATTE NE
921 PM CST SAT DEC 28 2013
.UPDATE...
ISSUED AT 918 PM CST SAT DEC 28 2013
SURFACE WINDS DIMINISHING ACROSS THE PANHANDLE AND SOUTHWEST TO
CANCEL THE WIND ADVISORY FOR AREAS GENERALLY WEST OF A LINE FROM
KILGORE TO MULLEN...TRYON..AND BRADY. FURTHER EAST STRONG WINDS
WILL LINGER A FEW MORE HOURS THEN DIMINISH ACROSS THE NORTH
CENTRAL EARLY MORNING.
&&
.SHORT TERM...(THIS EVENING THROUGH SUNDAY)
ISSUED AT 706 PM CST SAT DEC 28 2013
FORECAST UPDATED AS SNOW SHOWERS A LITTLE MORE AGRESSIVE AND
FURTHER SOUTH. THE SNOW SHOWERS ARE MOVING SOUTH AROUND 25 MPH
WITH LOW POPS INTRODUCED THROUGHOUT THROUGH MIDNIGHT AND TRENDED
TO THE LATEST RUC SOLUTION. NO ACCUMULATIONS EXPECTED ALTHOUGH
VISIBILITY MAY BE BRIEFLY REDUCED AS SNOW SHOWERS MOVE ACROSS
THROUGH MIDNIGHT.
.LONG TERM...(SUNDAY NIGHT THROUGH SATURDAY)
ISSUED AT 331 PM CST SAT DEC 28 2013
A PROGRESSIVE PATTERN CONTINUES IN THE NORTHWEST FLOW ACROSS THE
PLAINS THROUGH MOST OF NEXT WEEK.
THE NEXT STORM SYSTEM FROM THE CANADIAN ROCKIES COMES THROUGH
WESTERN NEBRASKA TUESDAY. THERE IS SOME ISENTROPIC LIFT INDICATED IN
THE 290-300K LAYER...BUT MOISTURE IS LACKING EVERYWHERE EXCEPT THE
AREA NORTH AND WEST OF ONEILL.
ANOTHER PULSE IS ON THE WAY FOR TUESDAY NIGHT THROUGH WEDNESDAY.
THAT ONE ALSO SHOWS ISENTROPIC LIFT IN THE 290-300K LAYER WITH SOME
FRONTOGENETIC ENHANCEMENT IN CENTRAL AND NORTH CENTRAL NEBRASKA.
THOUGH MOISTURE IS A LITTLE BETTER...IT IS STILL FAIRLY DRY IN THE
LOWER LAYERS. ALSO...THERE ARE SIGNIFICANT DIFFERENCES IN THE
LOCATIONS INDICATED IN THE THREE MEDIUM/LONG RANGE MODELS (THE
ECMWF...GEMNH AND US GFS)...SO WE WILL KEEP THE PROBABILITY LOW FOR
NOW.
ANOTHER SYSTEM IS EXPECTED TO DEVELOP IN COLORADO FRIDAY OR
SATURDAY...BUT THE UNCERTAINTY WITH THAT ONE IS HIGH.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z SUNDAY EVENING)
ISSUED AT 731 PM CST SAT DEC 28 2013
MARGINAL VISUAL FLIGHT RULES THROUGH MIDNIGHT AT TERMINAL KLBF AND
KVTN. LOW CEILINGS CONTINUE TO MOVE FURTHER SOUTH WITH SNOW
SHOWERS AS FAR SOUTH AS HIGHWAY 92. WINDS HAVE DIMINISHED ACROSS
THE WEST BUT WILL HOLD ONTO WIND ADVISORY IN THE EVENT SNOW
SHOWERS MIXED DOWN SOME STRONGER WINDS. THE THREAT FOR FREEZING
DRIZZLE APPEARS TO BE ENDING AS COLDER AIR ARRIVES BUT VISIBILITY
MAY DROP TO 5SM IN -SN. CEILINGS WILL BE LIFTING AFTER DAYBREAK
WITH AOB VISUAL FLIGHT RULES BEYOND 15Z AT BOTH TERMINALS.
&&
.LBF WATCHES/WARNINGS/ADVISORIES...
WIND CHILL ADVISORY FROM 3 AM CST /2 AM MST/ TO 9 AM CST /8 AM
MST/ SUNDAY FOR NEZ004>010-023>029-094.
WIND ADVISORY UNTIL 3 AM CST SUNDAY FOR NEZ007-010-027>029-038.
WIND ADVISORY UNTIL MIDNIGHT CST TONIGHT FOR NEZ005-006-008-009-
025-026-037.
&&
$$
UPDATE...KECK
SHORT TERM...KECK
LONG TERM...SPRINGER
AVIATION...KECK
AREA FORECAST DISCUSSION
NWS NORTH PLATTE NE
738 PM CST SAT DEC 28 2013
.SHORT TERM...(THIS EVENING THROUGH SUNDAY)
ISSUED AT 706 PM CST SAT DEC 28 2013
FORECAST UPDATED AS SNOW SHOWERS A LITTLE MORE AGRESSIVE AND
FURTHER SOUTH. THE SNOW SHOWERS ARE MOVING SOUTH AROUND 25 MPH
WITH LOW POPS INTRODUCED THROUGHOUT THROUGH MIDNIGHT AND TRENDED
TO THE LATEST RUC SOLUTION. NO ACCUMULATIONS EXPECTED ALTHOUGH
VISIBILITY MAY BE BRIEFLY REDUCED AS SNOW SHOWERS MOVE ACROSS
THROUGH MIDNIGHT.
.LONG TERM...(SUNDAY NIGHT THROUGH SATURDAY)
ISSUED AT 331 PM CST SAT DEC 28 2013
A PROGRESSIVE PATTERN CONTINUES IN THE NORTHWEST FLOW ACROSS THE
PLAINS THROUGH MOST OF NEXT WEEK.
THE NEXT STORM SYSTEM FROM THE CANADIAN ROCKIES COMES THROUGH
WESTERN NEBRASKA TUESDAY. THERE IS SOME ISENTROPIC LIFT INDICATED IN
THE 290-300K LAYER...BUT MOISTURE IS LACKING EVERYWHERE EXCEPT THE
AREA NORTH AND WEST OF ONEILL.
ANOTHER PULSE IS ON THE WAY FOR TUESDAY NIGHT THROUGH WEDNESDAY.
THAT ONE ALSO SHOWS ISENTROPIC LIFT IN THE 290-300K LAYER WITH SOME
FRONTOGENETIC ENHANCEMENT IN CENTRAL AND NORTH CENTRAL NEBRASKA.
THOUGH MOISTURE IS A LITTLE BETTER...IT IS STILL FAIRLY DRY IN THE
LOWER LAYERS. ALSO...THERE ARE SIGNIFICANT DIFFERENCES IN THE
LOCATIONS INDICATED IN THE THREE MEDIUM/LONG RANGE MODELS (THE
ECMWF...GEMNH AND US GFS)...SO WE WILL KEEP THE PROBABILITY LOW FOR
NOW.
ANOTHER SYSTEM IS EXPECTED TO DEVELOP IN COLORADO FRIDAY OR
SATURDAY...BUT THE UNCERTAINTY WITH THAT ONE IS HIGH.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z SUNDAY EVENING)
ISSUED AT 731 PM CST SAT DEC 28 2013
MARGINAL VISUAL FLIGHT RULES THROUGH MIDNIGHT AT TERMINAL KLBF AND
KVTN. LOW CEILINGS CONTINUE TO MOVE FURTHER SOUTH WITH SNOW
SHOWERS AS FAR SOUTH AS HIGHWAY 92. WINDS HAVE DIMINISHED ACROSS
THE WEST BUT WILL HOLD ONTO WIND ADVISORY IN THE EVENT SNOW
SHOWERS MIXED DOWN SOME STRONGER WINDS. THE THREAT FOR FREEZING
DRIZZLE APPEARS TO BE ENDING AS COLDER AIR ARRIVES BUT VISIBILITY
MAY DROP TO 5SM IN -SN. CEILINGS WILL BE LIFTING AFTER DAYBREAK
WITH AOB VISUAL FLIGHT RULES BEYOND 15Z AT BOTH TERMINALS.
&&
.LBF WATCHES/WARNINGS/ADVISORIES...
WIND ADVISORY UNTIL MIDNIGHT CST /11 PM MST/ TONIGHT FOR NEZ005-
006-008-009-022>026-035>037-056-057-059-071-094.
WIND CHILL ADVISORY FROM 3 AM CST /2 AM MST/ TO 9 AM CST /8 AM
MST/ SUNDAY FOR NEZ004>010-023>029-094.
WIND ADVISORY UNTIL 3 AM CST SUNDAY FOR NEZ007-010-027>029-038.
&&
$$
SHORT TERM...KECK
LONG TERM...SPRINGER
AVIATION...KECK
AREA FORECAST DISCUSSION
NWS NORTH PLATTE NE
710 PM CST SAT DEC 28 2013
.SHORT TERM...(THIS EVENING THROUGH SUNDAY)
ISSUED AT 706 PM CST SAT DEC 28 2013
FORECAST UPDATED AS SNOW SHOWERS A LITTLE MORE AGRESSIVE AND
FURTHER SOUTH. THE SNOW SHOWERS ARE MOVING SOUTH AROUND 25 MPH
WITH LOW POPS INTRODUCED THROUGHOUT THROUGH MIDNIGHT AND TRENDED
TO THE LATEST RUC SOLUTION. NO ACCUMULATIONS EXPECTED ALTHOUGH
VISIBILITY MAY BE BRIEFLY REDUCED AS SNOW SHOWERS MOVE ACROSS
THROUGH MIDNIGHT.
.LONG TERM...(SUNDAY NIGHT THROUGH SATURDAY)
ISSUED AT 331 PM CST SAT DEC 28 2013
A PROGRESSIVE PATTERN CONTINUES IN THE NORTHWEST FLOW ACROSS THE
PLAINS THROUGH MOST OF NEXT WEEK.
THE NEXT STORM SYSTEM FROM THE CANADIAN ROCKIES COMES THROUGH
WESTERN NEBRASKA TUESDAY. THERE IS SOME ISENTROPIC LIFT INDICATED IN
THE 290-300K LAYER...BUT MOISTURE IS LACKING EVERYWHERE EXCEPT THE
AREA NORTH AND WEST OF ONEILL.
ANOTHER PULSE IS ON THE WAY FOR TUESDAY NIGHT THROUGH WEDNESDAY.
THAT ONE ALSO SHOWS ISENTROPIC LIFT IN THE 290-300K LAYER WITH SOME
FRONTOGENETIC ENHANCEMENT IN CENTRAL AND NORTH CENTRAL NEBRASKA.
THOUGH MOISTURE IS A LITTLE BETTER...IT IS STILL FAIRLY DRY IN THE
LOWER LAYERS. ALSO...THERE ARE SIGNIFICANT DIFFERENCES IN THE
LOCATIONS INDICATED IN THE THREE MEDIUM/LONG RANGE MODELS (THE
ECMWF...GEMNH AND US GFS)...SO WE WILL KEEP THE PROBABILITY LOW FOR
NOW.
ANOTHER SYSTEM IS EXPECTED TO DEVELOP IN COLORADO FRIDAY OR
SATURDAY...BUT THE UNCERTAINTY WITH THAT ONE IS HIGH.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z SUNDAY EVENING)
ISSUED AT 624 PM CST SAT DEC 28 2013
CEILINGS WILL VARY FROM MARGINAL VFR AT KVTN TERMINAL TO VISUAL
FLIGHT RULES AT KLBF. CEILINGS HAVE LOWERED AT KVTN WITH SOME
LIGHT PRECIP WITH A MIX OF LIGHT SNOW OR FREEZING DRIZZLE THROUGH
03Z. PRECIPITATION LIGHT SO NOT LOOKING FOR LOWER VISIBILITY ATTM.
FURTHER SNOW PRECIPITATION ON RADAR WILL SPREAD SOUTH AS COLDER
AIR ARRIVES. SURFACE WINDS REMAIN STRONG AT 25 TO 35 KNOTS WITH
HIGHER GUSTS WITH WINDS TO SLOWLY DIMINISH MID MORNING SUNDAY.
CLOUDS WILL ALSO BE LIFTING AT THAT TIME FOR VISUAL FLIGHT RULES
BEYOND 15Z AT BOTH TERMINALS.
&&
.LBF WATCHES/WARNINGS/ADVISORIES...
WIND ADVISORY UNTIL MIDNIGHT CST /11 PM MST/ TONIGHT FOR NEZ005-
006-008-009-022>026-035>037-056-057-059-071-094.
WIND CHILL ADVISORY FROM 3 AM CST /2 AM MST/ TO 9 AM CST /8 AM
MST/ SUNDAY FOR NEZ004>010-023>029-094.
WIND ADVISORY UNTIL 3 AM CST SUNDAY FOR NEZ007-010-027>029-038.
&&
$$
SHORT TERM...KECK
LONG TERM...SPRINGER
AVIATION...KECK
AREA FORECAST DISCUSSION
NWS NORTH PLATTE NE
628 PM CST SAT DEC 28 2013
.SHORT TERM...(THIS EVENING THROUGH SUNDAY)
ISSUED AT 331 PM CST SAT DEC 28 2013
THE WIND ADVISORY LOOKS GOOD FOR MOST OF WESTERN AND NORTH CENTRAL
NEBRASKA TONIGHT. HAVE EXPANDED TO INCLUDE A BIT MORE OF SOUTHWEST
NEBRASKA...WHERE BOTH THE 18Z NAM AND RAP MODELS INDICATE A CORE OF
STRONGER WINDS JUST OFF THE SURFACE MOVING ACROSS THIS EVENING.
WINDS WILL DIMINISH ACROSS THE ENTIRE AREA LATE TONIGHT...BUT REMAIN
STRONG ENOUGH THAT WHEN COMBINED WITH TEMPERATURES NEAR OR JUST
BELOW ZERO ACROSS NORTHERN NEBRASKA...WIND CHILLS WILL REACH
ADVISORY CRITERIA. SO...HAVE ISSUED A WIND CHILL ADVISORY LATE
TONIGHT INTO SUNDAY MORNING FOR NORTHERN NEBRASKA.
STILL SOME CONCERN FOR A BIT OF FREEZING DRIZZLE ACROSS EASTERN
PORTIONS OF NORTH CENTRAL NEBRASKA THROUGH MID EVENING. BUFKIT
SOUNDING DATA JUST EAST OF THE ONEILL AREA SHOWS THE POTENTIAL UNTIL
MID EVENING...WHEN THE SATURATED LOWER LAYER DROPS QUICKLY BELOW
-10C. OTHERWISE THERE IS SOME POTENTIAL FOR A FEW SNOW SHOWERS OR
FLURRIES ELSEWHERE. HRRR MODEL HAS BEEN KEYING ON FLURRY POTENTIAL
ACROSS SOUTHWEST NEBRASKA IN AN AREA OF ENHANCED MID LEVEL
FRONTOGENESIS AND QG FORCING.
HIGH PRESSURE QUICKLY BUILDS INTO THE AREA SUNDAY...WITH WINDS
NEARLY CALM BY AFTERNOON. IT WILL BE COLD THOUGH WITH ARCTIC AIR IN
PLACE.
.LONG TERM...(SUNDAY NIGHT THROUGH SATURDAY)
ISSUED AT 331 PM CST SAT DEC 28 2013
A PROGRESSIVE PATTERN CONTINUES IN THE NORTHWEST FLOW ACROSS THE
PLAINS THROUGH MOST OF NEXT WEEK.
THE NEXT STORM SYSTEM FROM THE CANADIAN ROCKIES COMES THROUGH
WESTERN NEBRASKA TUESDAY. THERE IS SOME ISENTROPIC LIFT INDICATED IN
THE 290-300K LAYER...BUT MOISTURE IS LACKING EVERYWHERE EXCEPT THE
AREA NORTH AND WEST OF ONEILL.
ANOTHER PULSE IS ON THE WAY FOR TUESDAY NIGHT THROUGH WEDNESDAY.
THAT ONE ALSO SHOWS ISENTROPIC LIFT IN THE 290-300K LAYER WITH SOME
FRONTOGENETIC ENHANCEMENT IN CENTRAL AND NORTH CENTRAL NEBRASKA.
THOUGH MOISTURE IS A LITTLE BETTER...IT IS STILL FAIRLY DRY IN THE
LOWER LAYERS. ALSO...THERE ARE SIGNIFICANT DIFFERENCES IN THE
LOCATIONS INDICATED IN THE THREE MEDIUM/LONG RANGE MODELS (THE
ECMWF...GEMNH AND US GFS)...SO WE WILL KEEP THE PROBABILITY LOW FOR
NOW.
ANOTHER SYSTEM IS EXPECTED TO DEVELOP IN COLORADO FRIDAY OR
SATURDAY...BUT THE UNCERTAINTY WITH THAT ONE IS HIGH.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z SUNDAY EVENING)
ISSUED AT 624 PM CST SAT DEC 28 2013
CEILINGS WILL VARY FROM MARGINAL VFR AT KVTN TERMINAL TO VISUAL
FLIGHT RULES AT KLBF. CEILINGS HAVE LOWERED AT KVTN WITH SOME
LIGHT PRECIP WITH A MIX OF LIGHT SNOW OR FREEZING DRIZZLE THROUGH
03Z. PRECIPITATION LIGHT SO NOT LOOKING FOR LOWER VISIBILITY ATTM.
FURTHER SNOW PRECIPITATION ON RADAR WILL SPREAD SOUTH AS COLDER
AIR ARRIVES. SURFACE WINDS REMAIN STRONG AT 25 TO 35 KNOTS WITH
HIGHER GUSTS WITH WINDS TO SLOWLY DIMINISH MID MORNING SUNDAY.
CLOUDS WILL ALSO BE LIFTING AT THAT TIME FOR VISUAL FLIGHT RULES
BEYOND 15Z AT BOTH TERMINALS.
&&
.LBF WATCHES/WARNINGS/ADVISORIES...
WIND ADVISORY UNTIL MIDNIGHT CST /11 PM MST/ TONIGHT FOR NEZ005-
006-008-009-022>026-035>037-056-057-059-071-094.
WIND CHILL ADVISORY FROM 3 AM CST /2 AM MST/ TO 9 AM CST /8 AM
MST/ SUNDAY FOR NEZ004>010-023>029-094.
WIND ADVISORY UNTIL 3 AM CST SUNDAY FOR NEZ007-010-027>029-038.
&&
$$
SHORT TERM...TAYLOR
LONG TERM...SPRINGER
AVIATION...KECK
AREA FORECAST DISCUSSION
NWS HASTINGS NE
539 PM CST SAT DEC 28 2013
.SHORT TERM...(THIS EVENING THROUGH SUNDAY)
ISSUED AT 337 PM CST SAT DEC 28 2013
...A BRIEF BUT POTENT BLAST OF ARCTIC AIR AS TEMPS PLUNGE FROM
TODAY/S NEAR RECORD WARMTH...
ALOFT: PROGRESSIVE NW REMAINS IN PLACE. AN EMBEDDED POSITIVE-TILT
TROF WAS OVER THE NRN ROCKIES. THIS TROF WILL MOVE THRU HERE
TOMORROW...WITH NW FLOW TO FOLLOW.
SURFACE: LOW PRES HAS BEEN MIGRATING E ALONG AN ARCTIC COLD
FRONT...OUT OF THE DAKOTAS FROM THIS MORNING AND WAS OVER SWRN MN
AT 20Z. THE FRONT WAS SURGING S IN ITS WAKE AND IR SATELLITE
IMAGERY SUGGESTS THAT IT/S THRU THE SANDHILLS AND EXTENDS FROM
ALBION-LOUP CITY-LEXINGTON AT 20Z. THE FRONT SHOULD BE THRU THE
FCST AREA IN 6 HRS OR LESS...EXITING INTO CNTRL KS BY 9PM. STRONG
ARCTIC HIGH PRES BUILDS IN TONIGHT AS IT SLIDES INTO THE NRN
PLAINS. IT WILL WEAKEN TOMORROW AS IT CONTINUES DOWN THE MO RIVER
VALLEY.
UPDATED ADVISORY/HAZARDOUS WX OUTLOOK HAVE POSTED. GOSPER/DAWSON/
PHELPS COUNTIES ARE NOW INCLUDED. THE END TIME HAS ALSO BEEN MOVED
UP TO 3 AM...BUT ADVISORY COULD END UP BEING TERMINATED AS EARLY
AS 12 AM.
REST OF THIS AFTERNOON: WE PUT THE FINISHING TOUCHES ON ANOTHER
VERY NICE DAY FOR LATE DEC WITH NEAR-RECORD MUCH ABOVE NORMAL
WARMTH.
A CHECK OF GRI ASOS AT 335 PM VIA MODEM SHOWS A HIGH OF 62F. THE
FRONT HAS MOVED THRU AND THE TEMP IS DOWN TO 59F. CAME WITHIN 2F
OF TYING THE RECORD HIGH /64 IN 2002/.
WE HAVE BEEN WATCHING IMPRESSIVE PRES GRADIENT OVER ND/SD/MT/WY
TODAY WITH EQUALLY IMPRESSIVE WINDS. PEAK GUSTS OF 45-52 KTS HAVE
BEEN COMMON. THERE IS A CORE OF 40-55 KT WINDS AT 850 MB
COINCIDENT WITH THESE WINDS. THE RAPID CITY 88D CONFIRMS ITS
PRESENCE.
EXPECT DOWNWARD TRANSFER IN VERY STEEP LAPSE RATES/COLD AIR
ADVECTION AS THIS JET CORE DROPS INTO THE FCST AREA.
THE STRONGEST WINDS WILL OCCUR IN THE 6-8 HRS IMMEDIATELY
FOLLOWING PASSAGE OF THE COLD FRONT /IE BEFORE MIDNIGHT/.
VALENTINE HAD A PEAK WIND OF 45 KTS AT 218 PM.
THE WINDIEST LOCATIONS WILL BE ALONG AND N OF HWY 92. RAP TIME-
HEIGHT CROSS SECTIONS SHOW 45 KTS DOWN TO 1K FT WITH A CORE OF 50
KTS DOWN TO 1800 FT FROM 9PM-12AM. 18Z NAM HAS 52 KTS BUT ONLY AS
LOW AS 2K FT 6PM-9PM. BOTTOM LINE...WOULD NOT BE SURPRISED TO SEE
G50-55 MPH IN THESE AREAS THIS EVE.
15Z SREF PROBABILITIES FOR MEAN WINDS 30 MPH OR GREATER ARE
HIGHEST OVER CNTRL NEB N INTO THE SANDHILLS 6PM-11PM. THIS IS
WHERE THE ADVISORY HAS THE BEST CHANCE OF VERIFYING.
TONIGHT: WINDY AND TURNING MUCH COLDER. BECOMING MOSTLY CLOUDY AS
THE 900-850 MB LAYER COOLS TO SATURATION. EXTENSIVE MID-HIGH
CLOUDS WILL ALSO INVADE. LOW TEMPS ROUGHLY 8F COLDER THAN NORMAL.
TOMORROW: DECREASING CLOUDS AND WINDS. TEMPS MUCH COLDER THAN
NORMAL /BY 15-20F/.
.LONG TERM...(SUNDAY NIGHT THROUGH SATURDAY)
ISSUED AT 332 PM CST SAT DEC 28 2013
A 1035MB SURFACE HIGH PRESSURE SYSTEM WILL BUILD SOUTH ALONG THE
MISSOURI RIVER SUNDAY EVENING...AND EXPECT TEMPERATURES WILL DROP
OFF RATHER QUICKLY FOR THE FIRST PART OF THE NIGHT. AS THE SFC
RIDGE AXIS WEAKENS AND SHIFTS EASTWARD SUNDAY NIGHT...RETURN FLOW
SETS UP AND THE AIRMASS BEGINS TO MODERATE AND TEMPERATURES SHOULD
TREND UP HEADING INTO MONDAY MORNING.
THE UPPER TROUGH AXIS WILL TRANSLATE EAST/NORTHEASTWARD FOR THE
FIRST PART OF THE WEEK...WHICH ALLOWS FOR A REBOUND IN
TEMPERATURES FOR OUR AREA AS HEIGHTS RISE BEHIND THE SYSTEM. THIS
BEING SAID IT IS IMPORTANT TO NOTE THAT THE COLD AIR IS NOT THAT
FAR AWAY AND IF THE BAROCLINIC ZONE SHIFTS FARTHER SOUTH AND
WEST...IT WILL BE ACROSS US AND TEMPS WILL BE COLDER. THE BIGGEST
CHANGE IN THE FORECAST COMES IN THE TUESDAY TIME FRAME AS SEVERAL
OF THE LATEST OPERATIONAL MODELS NO LONGER BACK A COLD FRONT AS
FAR SOUTH INTO SC NEBRASKA AS PREVIOUS RUNS. MODELS ARE IN PRETTY
GOOD AGREEMENT THAT THE COLD AIR AND STRATUS WILL BE ORIENTED
ACROSS SOUTH DAKOTA/NORTHERN IOWA AND PERHAPS FAR NORTHERN
NEBRASKA THROUGH THE DAY...ALTHOUGH A COLD FRONT DOES ADVANCE
SOUTH IN THE AFTN. HAVE RAISED TEMPERATURES FOR TUESDAY...BUT WILL
NEED TO MONITOR THERMAL AND CLOUD FIELDS CLOSELY AS THE 12Z ECMWF
REMAINS COLDER THAN GFS/GEM/NAM IN THIS TIME FRAME.
A COLD FRONT PUSHES SOUTH TUESDAY/NEW YEARS EVE NIGHT AND MODELS
ARE NOT OVERLY ROBUST IN GENERATING PCPN WITH THIS BUT DID
MAINTAIN SOME VERY LOW POPS FOR LIGHT SNOW ACROSS OUR NORTHEAST
ZONES. LIGHT WINTRY PCPN IS POSSIBLE ON WEDNESDAY/NEW YEARS DAY AS
A 120KT JET NOSES SOUTH ALONG THE ROCKIES/HIGH PLAINS REGION AND
DEEPENS A TROUGH ACROSS THE PLAINS AND UPPER MIDWEST. COLDER AIR
ADVECTS SOUTH AND A BAND OF FRONTOGENETIC SNOWFALL IS POSSIBLE
INTO WEDNESDAY NIGHT.
THURSDAY WILL BE THE TRANSITION DAY BETWEEN THE COLD AIR AT THE
MIDDLE OF THE WEEK AND A WARMING TREND FOR THE END OF THE WEEK.
THE UPPER TROUGH AND COLD AIR ONCE AGAIN SLIDE EAST THURSDAY WITH
HEIGHTS RISING/MODERATING TEMPS IN ITS WAKE. FRIDAY IS SHAPING UP
TO BE MILD AGAIN WITH ABOVE NORMAL TEMPS IN SUBTLE RIDGING ALOFT.
SATURDAY TEMPS WILL BE DEPENDENT ON COLD FRONTAL TIMING WITH THE
GFS QUICKER WITH THE FRONT PASSAGE THAN THE ECMWF...AND GIVEN
MODEL DIFFERENCES DID NOT DEVIATE MUCH FROM INIT FOR DAY 7.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z SUNDAY EVENING)
ISSUED AT 534 PM CST SAT DEC 28 2013
MVFR CIGS WILL EVENTUALLY OVERTAKE THE TERMINAL OVER THE NEXT HOUR
OR TWO AS A STRONG COLD FRONT CONTINUES TO MAKE ITS WAY ACROSS
NEBRASKA. EXPECT THESE LOW CIGS TO PERSIST THROUGH ABOUT DAYBREAK
ON SUNDAY...BEFORE THEY ARE REPLACED BY A MID LEVEL CLOUD DECK
NEAR 12KFT. OTHERWISE...FOCUS REMAINS ON THE WINDS...WITH STRONG
WINDS UPSTREAM OF THE TERMINAL AT THIS TIME. HAVE ALREADY SEEN
GUSTS NEAR 40KTS AT ODX AND BBW...AND EXPECT THESE VERY STRONG
WINDS TO DEVELOP AND THEN PERSIST AT THE TERMINAL THROUGH THE
OVERNIGHT HOURS BEFORE RELAXING SOME DURING THE DAY ON SUNDAY.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...WIND ADVISORY UNTIL 3 AM CST SUNDAY FOR NEZ039>041-046>049-
060>064-072>077.
KS...NONE.
&&
$$
SHORT TERM...HALBLAUB
LONG TERM...FAY
AVIATION...ROSSI
AREA FORECAST DISCUSSION
NWS BUFFALO NY
1139 PM EST THU DEC 26 2013
.SYNOPSIS...
LAKE EFFECT SNOW WILL CONTINUE EAST OF THE LAKES OVERNIGHT WITH
LOCALIZED HEAVY ACCUMULATIONS EAST OF LAKE ONTARIO. A WEAK
DISTURBANCE MAY BRING A GENERAL LIGHT SNOW FRIDAY MORNING WITH LAKE
EFFECT SNOW SLOWLY TAPERING OFF EAST OF THE LAKES AS HIGH PRESSURE
EDGES NORTHWARD INTO THE REGION. A TEMPORARY WARMING TREND IS THEN
EXPECTED FOR THE WEEKEND BEFORE A SURGE OF ARCTIC AIR ARRIVES NEXT
WEEK.
&&
.NEAR TERM /THROUGH FRIDAY/...
WESTERLY FLOW LAKE SNOWS WILL CONTINUE ACROSS THE TUG HILL PLATEAU
GIVEN THE FULL LAKE FETCH AND CLOSER LOCATION OF LEFT ENTRANCE
REGION OF UPPER JET. SNOWFALL RATES OF 1 TO 2 INCHES PER HOUR
WILL BE COMMON WITHIN THE HEART OF THE BAND. A LAKE SNOW WARNING
WILL BE MAINTAINED FOR THE TUG HILL REGION WITH SNOWFALL TOTALS
EXCEEDING A FOOT.
LAKE ERIE SNOWS HAVE DIMINISHED CONSIDERABLY THE PAST FEW HOURS.
LATEST HRRR AND LOCAL WRF SHOWING THIS DIMINISHING TREND NICELY.
THEREFORE HAVE CANCELED THE ADVISORY FOR THIS AREA. MESOSCALE
MODELS DO SUGGEST SOME REDEVELOPMENT OFF LAKE ERIE LATE TONIGHT
AND FRIDAY MORNING...BUT THIS WILL BE FOCUSED ON A SOUTHWEST FLOW
WITH A LAKE BAND LIKELY TO DEVELOP TOWARD THE SUBURBS SOUTH OF
BUFFALO WITH A SNOWBURST DURING THE EARLY MORNING COMMUTE...THEN
SLIPPING BACK TO THE SOUTH AND WEAKENING BY MID MORNING.
TEMPERATURES OVERNIGHT WILL FALL TO THE MID TEENS TO LOW 20S...
MODERATED FROM FALLING TOO FAR BY PARTIAL CLOUD COVER AND WESTERLY
WINDS BACKING TO SOUTH BY DAYBREAK. HIGH TEMPS ON FRIDAY WILL BE
IN THE UPPER 20S TO LOWER 30S...MILDER THAN HAVE BEEN THE PAST FEW
DAYS.
&&
.SHORT TERM /FRIDAY NIGHT THROUGH SUNDAY NIGHT/...
WHILE A DEEP POLAR VORTEX WILL REMAIN IN PLACE IN THE VCNTY OF
HUDSON BAY DURING THIS PERIOD...THE UPPER LEVEL FLOW ACROSS THE
GREAT LAKES WILL LARGELY BE ZONAL. THIS WILL TEMPORARILY BLOCK THE
SUPPLY OF VERY COLD AIR...WHILE EXPANSIVE SFC HIGH PRESSURE OVER
THE SOUTHEAST WILL CIRCULATE MILDER CONDITIONS NORTHWARDS ACROSS
OUR REGION. OTHERWISE...UNEVENTFUL WEATHER CAN BE EXPECTED UNTIL
LATER IN THE WEEKEND WHEN A COMPLEX STORM SYSTEM FEATURING A
COASTAL LOW WILL HAVE TO BE WATCHED.
UP UNTIL THAT TIME...THE SYNOPTIC PATTERN ACROSS OUR REGION WILL BE
SIMPLE AND STRAIGHTFORWARD. FOR FRIDAY NIGHT THROUGH SATURDAY
NIGHT...A LARGE AREA OF HIGH PRESSURE WILL BE ROOTED ACROSS ALL OF
THE DEEP SOUTH WHILE AN ARCTIC FRONTAL BOUNDARY STRETCHING FROM
CENTRAL QUEBEC TO THE UPPER GREAT LAKES WILL SLOWLY SAG SOUTH
TOWARDS OUR REGION. THIS WILL ENCOURAGE MODERATELY STRONG WARM
ADVECTION ACROSS THE LOWER GREAT LAKES REGION SO THAT H85 TEMPS WILL
FLEETINGLY VISIT THE POSITIVE SIDE OF ZERO C. AFTERNOON HIGHS ON
SATURDAY SHOULD BE WITHIN A COUPLE DEGREES OF 40F...WHILE OVERNIGHT
LOWS WILL BE IN THE UPPER 20S AND LOWER 30S. MEANWHILE THE CLOSEST
PCPN DURING THIS 24 HOUR WINDOW WILL BE NORTH OF THE THOUSAND
ISLANDS.
THINGS WILL THEN BECOME MORE COMPLICATED ON SUNDAY.
A WAVE OVER LAKE MICHIGAN WILL LIFT NORTHEAST ALONG THE NEARLY
STALLED ARCTIC FRONTAL BOUNDARY AND TRANSFER SOME OF ITS ENERGY TO A
SOUTHERN STREAM LOW THAT WILL BE WORKING UP THE MID ATLANTIC COAST.
THIS WILL PLACE THE BULK OF OUR FORECAST AREA IN A `RIP OFF ZONE` OF
SORTS...BETWEEN THE TWO MAIN CENTERS OF SYNOPTIC FORCING. THIS WILL
INCLUDE A STRONG AREA OF JET INDUCED LIFT THAT WILL TRACK BY JUST TO
OUR SOUTHEAST. WHILE THERE COULD BE A LITTLE LIGHT SNOW AROUND...
MAINLY ACROSS THE SRN TIER AND PORTIONS OF THE FINGER LAKES...
ACCUMULATIONS SHOULD BE INSIGNIFICANT. TEMPERATURES MAY EVEN BE HIGH
ENOUGH TO MIX IN OR CHANGE THE PCPN TO A SHORT PERIOD OF LIGHT RAIN.
AS THE NRN BRANCH LOW MOVES BY AND COMPLETES ITS ENERGY TRANSFER TO
THE COAST SUNDAY EVENING...THE ARCTIC FRONT THAT IT USED AS A
PATHWAY WILL SURGE ACROSS OUR FORECAST AREA. THIS WILL PLUNGE OUR
TEMPERATURES BACK BELOW NORMAL VALUES...INTO THE TEENS FOR MANY
AREAS. THESE VALUES WILL BE ABOUT 15 DEG LOWER THAN THOSE FROM THE
PREVIOUS COUPLE NIGHTS.
&&
.LONG TERM /MONDAY THROUGH THURSDAY/...
THE NORTHERN HEMISPHERE WILL FEATURE ANOMALOUSLY STRONG RIDGING OVER
THE RUSSIAN ARCTIC AND A LARGE POLAR VORTEX ACROSS THE HUDSON BAY
WHICH WILL SET THE STAGE FOR A CROSS POLAR FLOW. THE COLDEST OF THE
AIR (H85 -40C) HOWEVER...WILL REMAIN LOCKED UP OVER FAR NORTHERN
ONTARIO AND QUEBEC. A LITTLE CLOSER TO HOME...THE DEEP FULL LATITUDE
TROUGH MENTIONED OVER EASTERN NORTH AMERICA WILL CAUSE SOME OF THE
ARCTIC AIR (-22C) TO SETTLE SOUTH ACROSS WESTERN AND NORTH CENTRAL
NY DURING THIS PERIOD.
A POTENT FRONTAL BOUNDARY WILL SURGE ACROSS OUR FORECAST AREA SUNDAY
NIGHT INTO THE EARLY MORNING HOURS ON MONDAY. THERE WILL ALSO BE
THE POTENTIAL FOR A BRIEF PERIOD OF HEAVY SNOWFALL ACCOMPANYING THE
FRONTAL PASSAGE. BEHIND THE ARCTIC FRONT...A FRIGGED AIR MASS WILL SPILL
IN ACROSS WESTERN AND NORTH CENTRAL NY (850H TEMPS FALLING FROM -4C
TO -20 BY MONDAY NIGHT)WITH SOME MEASURE OF LAKE EFFECT SNOWS. THE
LARGE POLAR VORTEX OVER HUDSON BAY WILL SLOWLY DRIFT EASTWARD MONDAY
NIGHT INTO TUESDAY...AS IT DOES A WEAK CLIPPER TYPE SYSTEM WILL MOVE
THROUGH THE BASE OF THE TROUGH. THIS SYSTEM WILL BRING A CHANCE FOR
SOME MORE LIGHT SNOWS DURING THE DAY ON TUESDAY. FOLLOWING ITS
PASSAGE...A RE-ENFORCING SHOT OF COLD AIR WILL FILTER IN ACROSS THE
REGION (85H BACK TO -21C) AND ANOTHER ROUND OF LAKE EFFECT SNOWS
WILL DEVELOP OFF OF BOTH LAKE ERIE AND ONTARIO.
THE ECMWF/GFS SUGGEST THAT A WEAK SURFACE HIGH WILL BUILD SLOWLY
INTO THE REGION LATE WEDNESDAY. MEANWHILE ANOTHER CLIPPER TYPE STORM
SYSTEM MAY BE CROSSING THE UPPER GREAT LAKES. ALTHOUGH...AT THIS
POINT SLIGHT DIFFERENCES ARISE WHETHER THURSDAY WILL BE A RATHER
QUIET WX DAY OR THERE WILL BE SOME MORE LIGHT SNOW FROM THIS
CLIPPER SYSTEM MOVING ACROSS THE GREAT LAKES. ONE THING IS FOR
SURE...TEMPERATURES DURING THIS PERIOD WILL DEFINITELY BE BELOW
AVERAGE.
&&
.AVIATION /06Z FRIDAY THROUGH TUESDAY/...
THE MAIN IMPACT ON AVIATION THROUGH OVERNIGHT WILL BE LAKE EFFECT
SNOWS EAST OF THE LAKES WITH AREAS OF IFR VSBY AFFECTING MAINLY
AREAS BETWEEN KBUF AND KJHW AND BETWEEN KART AND KFZY.
THERE MAY BE A NORTHWARD MOTION TO BRING IFR VSBY TO KBUF AND KIAG
FROM 09Z TO 13Z AND KART FROM 12Z TO 16Z.
OUTLOOK...
FRIDAY...MVFR/IFR IN LIGHT SNOW IMPROVING TO VFR IN THE AFTERNOON.
SATURDAY AND SUNDAY...MAINLY VFR.
MONDAY AND TUESDAY...VFR/MVFR WITH A CHANCE OF SNOW SHOWERS. LOCAL
IFR IN LAKE EFFECT SNOW SHOWERS SOUTHEAST OF THE LAKES.
&&
.MARINE...
MODERATE SOUTHERLY WINDS EARLY THIS MORNING WILL BECOME MORE
SOUTHWEST AND WEST TODAY WITH MODERATE WESTERLIES CONTINUING THROUGH
TONIGHT. THIS WILL PRODUCE ONGOING SMALL CRAFT ADVISORY CONDITIONS
ON BOTH LAKES THROUGH FRIDAY MORNING. A BRIEF DIMINISHING TREND IN
WINDS IS POSSIBLE FOR A FEW HOURS FRIDAY AFTERNOON BEFORE PICKING UP
AGAIN FRIDAY NIGHT THROUGH AT LEAST SATURDAY.
&&
.BUF WATCHES/WARNINGS/ADVISORIES...
NY...LAKE EFFECT SNOW WARNING UNTIL 4 PM EST FRIDAY FOR NYZ006>008.
MARINE...SMALL CRAFT ADVISORY UNTIL 1 PM EST FRIDAY FOR LEZ040-041.
SMALL CRAFT ADVISORY UNTIL 1 PM EST FRIDAY FOR
LOZ043>045.
SMALL CRAFT ADVISORY UNTIL 7 AM EST FRIDAY FOR LOZ042.
&&
$$
SYNOPSIS...TMA/WCH
NEAR TERM...TMA/WCH
SHORT TERM...RSH
LONG TERM...AR/RSH
AVIATION...TMA/WCH
MARINE...WCH
AREA FORECAST DISCUSSION
NWS BISMARCK ND
911 PM CST SAT DEC 28 2013
.UPDATE...
ISSUED AT 910 PM CST SAT DEC 28 2013
ALLOWED THE BLIZZARD WARNING TO EXPIRE OVER THE JAMES RIVER BASIN.
TEMPERATURES WILL CONTINUE TO PLUMMET AS AN ARCTIC AIR MASS BUILDS
INTO THE REGION.
OTHERWISE...THE LATEST RAP AND UPSTREAM OBS INDICATE SCATTERED
FLURRIES DEVELOPING OVER WESTERN NORTH DAKOTA AFTER MIDNIGHT.
AFTER COLLABORATING WITH THE MONTANA OFFICES AND RAPID
CITY...DECIDED TO ADD FLURRIES OVER WESTERN NORTH DAKOTA.
OTHERWISE...THE REMAINING FORECAST ELEMENTS ARE IN GOOD SHAPE. THE
UPDATED GRIDDED AND TEXT PRODUCTS HAVE BEEN SENT.
UPDATE ISSUED AT 719 PM CST SAT DEC 28 2013
SENT OUT AN UPDATE TO ALLOW THE BLIZZARD WARNING TO EXPIRE ACROSS
THE NORTHEASTERN CWA THIS EVENING. HOWEVER...MAINTAINED THE
BLIZZARD WARNING FOR THE SOUTHERN JAMES RIVER BASIN FOR THE NEXT
FEW HOURS AS WINDS CONTINUE TO GUST UP TO 40 MPH GENERATING
BLOWING SNOW.
THE UPDATED PRODUCTS HAVE BEEN SENT.
UPDATE ISSUED AT 520 PM CST SAT DEC 28 2013
UPDATED THE FORECAST TO CANCEL THE BLIZZARD WARNING FOR AREAS
ALONG AND WEST OF HIGHWAY 83 ACROSS NORTHWESTERN NORTH DAKOTA.
WINDS CONTINUE TO COME DOWN AND VISIBILITIES CONTINUE TO IMPROVE.
HOWEVER...ACROSS THE EASTERN CWA...BLIZZARD CONDITIONS CONTINUE TO
BE REPORTED...ESPECIALLY ACROSS THE JAMES RIVER BASIN. WILL KEEP
THE BLIZZARD WARNING IN EFFECT THROUGH EARLY EVENING THERE AS A RESULT.
IN ADDITION...EXPANDED THE AREAL COVERAGE OF THE WIND CHILL
WARNING BASED ON LATEST OBS/TRENDS. THE UPDATED PRODUCTS HAVE BEEN
SENT.
&&
.SHORT TERM...(THIS EVENING THROUGH SUNDAY)
ISSUED AT 311 PM CST SAT DEC 28 2013
MAIN CONCERNS ARE WINTER HEADLINES AND DANGEROUS WIND CHILLS AS
ARCTIC AIR CONTINUES TO OVERSPREAD THE STATE. LOW PRESSURE CENTER
HAS MOVED TO SOUTHERN MINNESOTA WITH STRONG NORTHWEST WINDS
CONTINUING ACROSS OUR REGION.
BLIZZARD WARNING REMAINS IN EFFECT FOR MUCH OF NORTHERN CWA INTO
THE JAMES RIVER VALLEY INTO THE EARLY EVENING. CONDITIONS ARE
BEGINNING TO IMPROVE ACROSS THE NORTHWEST AND EXPECTED TO
DETERIORATE SOUTHEAST INTO THIS EVENING AS BAND OF LIGHT SNOW
SPREADS ACROSS THAT AREA WITH VERY STRONG WINDS CONTINUING.
BLIZZARD WARNING ENDS AT 01Z EVERYWHERE EXCEPT FAR SOUTHEAST WHICH
CONTINUES UNTIL 3Z...WHEN CONDITIONS SHOULD IMPROVE.
WIND CHILLS AT 21Z RANGED FROM 20 TO 30 BELOW ZERO ACROSS THE NORTH
AND THE NEGATIVE TEENS SOUTH. ENTIRE AREA IS COVERED BY WIND CHILL
ADVISORY WITH A WIND CHILL WARNING REMAINING IN PLACE ACROSS THE
NORTHEAST WITH WIND CHILLS TO 45 BELOW EXPECTED TONIGHT. MODELS IN
GOOD AGREEMENT WITH HIGH PRESSURE BUILDING IN ACROSS THE STATE
OVERNIGHT ALONG WITH DIMINISHING WINDS AND CLEARING SKIES. RETURN
FLOW SETS UP BY SUNDAY AFTERNOON ACROSS THE WEST AS HIGH PRESSURE
CONTINUES TO SLIDES OVER EASTERN SOUTH DAKOTA WITH INCREASING
CLOUDS AND SOME MODERATION IN TEMPERATURES REACHING SINGLE DIGITS
ABOVE ZERO WEST AND BELOW ZERO ELSEWHERE.
.LONG TERM...(SUNDAY NIGHT THROUGH SATURDAY)
ISSUED AT 311 PM CST SAT DEC 28 2013
THE HIGHLIGHTS OF THE EXTENDED FORECAST ARE DANGEROUS WIND CHILLS
FOR MUCH OF THE AREA SUNDAY THROUGH TUESDAY NIGHTS...AND
ACCUMULATING SNOW TUESDAY.
THE 12 UTC CONSENSUS IS IN AGREEMENT ON THE THE BOUNDARY OF THE
ARCTIC AIRMASS TO REMAIN ACROSS EASTERN MONTANA INTO SOUTHWEST
NORTH DAKOTA SUNDAY NIGHT THROUGH WEDNESDAY. THUS...DANGEROUS
NIGHTTIME AND EARLY MORNING WIND CHILLS SHOULD CONTINUE ACROSS
MUCH OF NORTHERN AND CENTRAL NORTH DAKOTA SUNDAY THROUGH WEDNESDAY
NIGHTS...WITH THE RELATIVELY WARMER SOUTHWEST FORECAST AT THIS
TIME TO REMAIN ABOVE ADVISORY CRITERIA.
IN REGARDS TO PRECIPITATION...A WAVE COMING ONSHORE TO BRITISH
COLUMBIA MONDAY IS FORECAST TO PROPAGATE SOUTHEAST AND INTERACT
WITH THE LOW LEVEL BAROCLINIC ZONE ON TUESDAY. AS A RESULT...A
BAND OF LIGHT TO MODERATE ACCUMULATING SNOW MAY BE POSSIBLE ACROSS
THE WEST AND FAR SOUTH CENTRAL. ADVISORY LEVEL SNOWFALL
ACCUMULATIONS MAY BE POSSIBLE...HOWEVER...WINDS ARE EXPECTED TO BE
LIGHT.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z SUNDAY EVENING)
ISSUED AT 910 PM CST SAT DEC 28 2013
CONDITIONS WILL GRADUALLY IMPROVE FROM NORTHWEST TO SOUTHEAST
TONIGHT THROUGH SUNDAY AS HIGH PRESSURE BUILDS IN.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
WIND CHILL ADVISORY UNTIL 1 PM CST /NOON MST/ SUNDAY FOR NDZ001-
009-010-017>021-031>035-040>046.
WIND CHILL WARNING UNTIL 1 PM CST SUNDAY FOR NDZ002>005-011>013-
022-023-025-036-037-047-048-050-051.
&&
$$
UPDATE...TM
SHORT TERM...JNS
LONG TERM...AYD
AVIATION...TM
AREA FORECAST DISCUSSION
NWS WILMINGTON OH
938 PM EST SAT DEC 28 2013
.SYNOPSIS...
RAIN WILL OCCUR WELL NORTH AND WEST OF A LOW PRESSURE SYSTEM THAT
WILL TRACK FROM THE GULF COAST INTO THE MID ATLANTIC TONIGHT INTO
TOMORROW. A COLD FRONT MOVING IN FROM THE NORTHWEST WILL QUICKLY
FOLLOW LATE SUNDAY INTO SUNDAY EVENING. HIGH PRESSURE WILL BUILD
IN MONDAY.
&&
.NEAR TERM /UNTIL 6 AM SUNDAY MORNING/...
SHIELD OF RAIN CONTINUES TO ADVANCE NORTH NORTHEAST ACROSS
KENTUCKY. THE WESTERN EDGE OF THIS LOOKS RAGGED BUT SOME LIGHT
PRECIPITATION IS STILL LIKELY REACHING THE GROUND THERE. LATEST
HRRR AND RAP RUNS HAVE COME INTO PRETTY GOOD AGREEMENT IN
SPREADING THE RAIN ACROSS MOST OF THE FORECAST AREA LATE TONIGHT
INTO SUNDAY MORNING. PROBABLY WILL NOT BE A STEADY RAIN
PARTICULARLY IN THE WESTERN AND NORTHERN AREAS BUT CHANCE OF
MEASURABLE PRECIPITATION CERTAINLY LOOKS HIGHER. THUS POPS HAVE
BEEN NUDGED UPWARD AGAIN.
TEMPERATURES WERE ADJUSTED TO ACCOUNT FOR RECENT OBSERVATIONAL
TRENDS WITH OUTLYING AREAS DROPPING A BIT FASTER THIS EVENING
DESPITE EXTENSIVE HIGH CLOUDS. EXPECT ONCE RAIN AND INCREASED LOW
LEVEL MOISTURE ARRIVE LATER TONIGHT THAT READINGS WILL LEVEL OUT
AND PERHAPS INCREASE A DEGREE OR TWO IN SOME PLACES.
&&
.SHORT TERM /6 AM SUNDAY MORNING THROUGH MONDAY NIGHT/...
CUT DOWN ON THE HIGH TEMPERATURES SUNDAY WHERE RAIN WOULD BE
STARTING THE DAY BUT THIS WAS ONLY ABOUT 2 DEGREES. NORTHERN AND
NORTHWEST TEMPS WERE LOOKING GOOD IN THE LOWER 40S.
RAIN WILL EXIT DURING THE MORNING AND A LULL IN PRECIPITATION IS
CALLED FOR IN THE EARLY AFTERNOON. UPPER LEVEL SHORTWAVE IS
HELPING SHUNT THE WESTERN EDGE OF THE PRECIPITATION ALONG QUICKLY
IN THE EARLY AFTERNOON. WHILE NOT A TYPICAL FIELD USED FOR
TIMING...THE H7 OMEGA IS SHOWING A PRONOUNCED MINIMA AT 15 AND 18Z
WHICH SHOULD INDICATE THE BACK EDGE OF THE RAINFALL.
ONCE COLDER AIR IS USHERED IN LATER IN THE DAY...LOOK FOR THE WIND
SHIFT TO NORTHWEST...ANY LINGERING MOISTURE WILL BE WRUNG OUT BY
THE FALLING TEMPERATURES THROUGH THE ATMOSPHERE AND A QUICK
TRANSITION TO SCATTERED SNOW SHOWERS APPEARS TO BE IN THE OFFING.
ANY OF THESE SNOW SHOWERS SHOULD BE LIGHT AND NOT A PROBLEM IN AND
OF THEMSELVES...LINGERING THROUGH ABOUT MIDNIGHT AND THEN TURNING
OFF AS THE AIRMASS DRIES SIGNIFICANTLY.
HIGH PRESSURE WILL BUILD OVER THE MIDWEST SUNDAY NIGHT AND MONDAY
AND CONTINUE TO FILTER IN COLDER AND DRIER AIR FOR ANOTHER TASTE
OF WINTER TO THE OHIO VALLEY FOR THE EARLY PART OF THE WEEK.
&&
.LONG TERM /TUESDAY THROUGH SATURDAY/...
EXTENDED MODELS HAVE CONVERGED WITH THEIR SOLUTIONS...BUT THERE
REMAINS SOME DIFFERENCES WITH THE DETAILS.
PERIOD BEGINS WITH A SYSTEM PASSING NORTH OF THE REGION THROUGH THE
GREAT LAKES. IT LOOKS LIKE THE PCPN SHOULD STAY TO THE N...WITH ONLY
SOME CLOUDS. MODELS THEN DROP SOME H5 ENERGY INTO THE ERN U.S. TROF
TUESDAY NIGHT. AN AREA OF ISENTROPIC LIFT ASSOCIATED WITH A WEAK
LOW/SFC TROF SWINGS ACROSS THE REGION TUESDAY NIGHT INTO WEDNESDAY.
THIS LIFT CAUSES AN AREA OF SNOW..MAINLY ACROSS THE NRN HALF OF THE
FA.
ON THURSDAY...THE MODELS PHASE SOME SRN AND NRN STREAM ENERGY ACROSS
THE ERN U.S. WHILE THE GFS/ECMWF AND CMC HEMISPHERIC ALL HAVE A
SYSTEM THAT AFFECTS THE AREA ON THURSDAY...THE STRENGTH OF THE
SYSTEM VARIES. WENT WITH A 12Z GFS/00Z ECMWF BLEND. THIS SPREADS
SNOW ACROSS MOST OF THE REGION WITH SOME RAIN/SNOW IN THE SE. HIGH
PRESSURE BUILDS IN FOR FRIDAY INTO SATURDAY.
WARMED UP HIGHS ON TUESDAY TO THE UPPER 20S IN WEST CENTRAL OHIO TO
THE MID 30S IN NRN KY. WITH THE WEAK CLIPPER TYPE SYSTEM ON
WEDNESDAY HIGHS WILL BE HELD DOWN INTO THE MID 20S TO LOWER 30S.
HIGHS WILL REMAIN ABOUT THE SAME THURSDAY INTO FRIDAY BEFORE WARMING
A FEW DEGREES SATURDAY. LOWS WILL TYPICALLY BE IN THE TEENS TO LOW
20S.
&&
.AVIATION /03Z SUNDAY THROUGH THURSDAY/...
RAIN WELL NORTH OF A LOW MOVING OUT OF THE GULF WILL SPREAD ACROSS
THE TERMINALS AFTER 06Z. MOST OF THE RAIN WILL BE LIGHT WITH NOT
MUCH IF ANY VISIBILITY RESTRICTION. BUT LOW LEVELS WILL MOISTEN
SUFFICIENTLY FOR MVFR CEILINGS TO DEVELOP BELOW 2000 FT LATE
TONIGHT. THERE IS THE POTENTIAL FOR THESE CEILINGS TO DROP TO IFR
BY 12Z BUT CONFIDENCE IS FAIRLY LOW ON THIS POSSIBILITY. RAIN WILL
PUSH OFF TO THE EAST DURING THE DAY BUT MVFR CEILINGS WILL PERSIST
THROUGH THE END OF THE TAF PERIOD. THERE COULD BE SOME IMPROVEMENT
ABOVE 2000 FT THRESHOLD AFTER 18Z. A COLD FRONT WILL PUSH INTO
KDAY AND KCVG/KLUK VERY LATE IN THE TAF PERIOD WHICH COULD BRING
SOME RAIN/SNOW SHOWERS.
OUTLOOK...MVFR CEILINGS WILL LIKELY CONTINUE INTO SUNDAY NIGHT.
MVFR CEILINGS POSSIBLE WEDNESDAY AFTERNOON INTO THURSDAY. MVFR TO
IFR VISIBILITIES POSSIBLE THURSDAY.
&&
.ILN WATCHES/WARNINGS/ADVISORIES...
OH...NONE.
KY...NONE.
IN...NONE.
&&
$$
SYNOPSIS...
NEAR TERM...
SHORT TERM...FRANKS
LONG TERM...SITES
AVIATION...
AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NWS RAPID CITY SD
801 PM MST SAT DEC 28 2013
.UPDATE...
ISSUED AT 800 PM MST SAT DEC 28 2013
AFTER RAP AS WELL AS LATEST RAP MODEL HAD FLURRIES COMING DOWN
FROM ND/MT AS WEAK SHORTWAVE DROPEDS INTO THE NORTHERN PLAINS.
LATEST RADAR/OBSEVATIONAL TRENDS SUPPORT...SO WILL HAVE FLURRIES
GOING OVER ENTIRE CWA ENTIRE NIGHT.
UPDATE ISSUED AT 557 PM MST SAT DEC 28 2013
LATEST RADAR TRENDS AS WELL AS SURFACE OBSERVATIONS SHOWED
-SN/--SN POPPING UP AS ARCTIC AIR SETTLES INTO THE CWA. WILL
INTRODUCE LOW POPS/FLURRIES TO SOUTHWEST 2/3RDS OF AREA FOR THIS
EVENING.
&&
.SHORT TERM...THIS EVENING THROUGH SUNDAY NIGHT
ISSUED AT 225 PM MST SAT DEC 28 2013
THE ARCTIC FRONT HAS ARRIVED FORCEFULLY AS HIGH WIND WARNING
CRITERIA HAVE BEEN MET ACROSS NWRN INTO WCNTRL SD AND 24-HR
TEMPERATURE DROPS OF -20 TO -40F ARE COMMON ACROSS THE CWA.
SNOWFALL HAS BEEN MINIMAL...AND CONFINED MOSTLY TO NERN WY AND FAR
NWRN SD AS CONFIRMED BY WEBCAMS AND SFC/RADAR OBS.
THE LATEST WATER VAPOR IMAGES SHOW THE UPPER TROUGH AXIS NEARING THE
NWRN CWA...AND RADAR IMAGES SHOW A FEW BANDS OF SNOW MOVING ACROSS
WCNTRL SD. THE STRONG SFC PRESSURE RISES OF 6-8 MB/3HR WERE CENTERED
OVER SCNTRL ND AND MOVING SOUTHEAST. THESE RISES ALSO HAVE BEEN
WEAKENING WITH TIME (MORESO THAN EXPECTED TO OCCUR WITH THE SEMI-
DIURNAL TIDE)...THUS THE WIND SPEEDS SHOULD TREND DOWNWARD OVER THE
NEXT SEVERAL HOURS. THE COLD ADVECTION STILL WAS QUITE STRONG ACROSS
THE CWA...AND WILL CONTINUE TO BE SO THROUGH THE EARLY EVENING. THIS
SUPPORTS THE WIND CHILL ADVY THAT IS IN EFFECT FOR NWRN SD TONIGHT.
ON THE LARGER-SCALE...THE SHORT-WAVE TROUGH WILL MOVE EAST OF THE
CWA OVERNIGHT AS ANOTHER ONE DROPS SOUTH ACROSS ND BY 12Z SUNDAY. A
SURFACE HIGH WILL BUILD OVER THE DAKOTAS...HELPING TO LESSEN THE
WINDS...BUT ALSO CONTINUING TO USHER COLD AIR INTO THE REGION. SNOW
SHOULD END FAIRLY QUICKLY THIS EVENING AS THE FORCING IS WEAK AND
MOISTURE IS MINIMAL. THE 850-MB TEMPS ALSO MAY RISE A FEW DEGREES BY
12Z AS THE COLDEST POCKET OF AIR IS PROGGED TO BE JUST SOUTHEAST OF
THE CWA.
ON SUNDAY A LEE TROF WILL DEVELOP OVER ERN WY IN RESPONSE TO THE
NEXT APPROACHING SHORT-WAVE TROUGH THAT WILL REACH ERN MT AND WY BY
24Z. THE RESULT WILL BE LOW-LEVEL WARM ADVECTION ACROSS MUCH OF THE
CWA AS THE TIGHT BAROCLINIC ZONE SHIFTS EASTWARD. A LACK OF MIXING
WILL PREVENT THIS WARM AIR FROM AFFECTING SURFACE TEMPERATURES OVER
THE ERN HALF OF THE CWA.
ON SUNDAY NIGHT THERE SHOULD BE A SLUG OF MIDLEVEL MOISTURE AS ONE
SHORT-WAVE TROUGH PASSES OVER THE CWA AND ANOTHER ONE FOLLOWS
QUICKLY BEHIND THE FIRST. THE SURFACE TROUGH WILL MOVE EAST AS
WELL...ENGENDERING MIXING AND STEADY/RISING TEMPERATURES OVERNIGHT.
SOME UPSLOPE SNOW APPEARS LIKELY...ALTHOUGH LOW-LEVEL MOISTURE WILL
LIMIT THE CHANCE OF SNOW ACROSS THE PLAINS.
&&
.LONG TERM...MONDAY THROUGH SATURDAY
ISSUED AT 225 PM MST SAT DEC 28 2013
ACTIVE NW FLOW THROUGH THE MIDDLE OF THE WEEK...WITH SEVERAL
SHORT-WAVE TROUGHS EXPECTED TO ADVECT SE ACROSS THE NORTHERN
PLAINS. POSITIVE HEIGHT ANOMALY OVER THE EASTERN PAC WILL
PERSIST...WITH RIDGE-TOPPING IMPULSES SQUELCHING THE RIDGE
AMPLITUDE AT TIMES. THE STRENGTH OF THE WESTERN CONUS RIDGE WILL
DICTATE THE LOCATION OF THE WAVERING FRONTAL BOUNDARY ACROSS THE
REGION...WITH THIS FEATURE LIKELY TO REMAIN GENERALLY ACROSS THE
FA THROUGH THE MIDDLE OF NEXT WEEK. WESTERN AREAS WILL TEND TO BE
AT OR ABOVE SEASONAL NORMS...WITH EASTERN AREAS REMAINING BELOW
NORMAL. DETERMINISTIC AND ENSEMBLE SOLUTIONS ARE SUPPORTING
ANOTHER RESURGENCE OF THE WESTERN CONUS RIDGE BY WED OF NEXT WEEK
AS THE SE CANADIAN NEGATIVE HEIGHT ANOMALY SHIFTS RAPIDLY EAST
GIVEN A STRONG ASSOCIATED NORTHERN-ATLANTIC UPPER JET. THIS WILL
ALLOW WARMER AIR TO SHIFT BACK EAST OFF THE ROCKIES AND INTO THE
NORTHERN PLAINS...UNTIL THE NEXT BUBBLE OF ARCTIC AIR ADVANCES
SOUTH TOWARD THE REGION THE FOLLOWING WEEKEND...BEING AIDED BY
ANOTHER POWERFUL NORTHERN PAC UPPER TROUGH...WITH THE CENTRAL
CANADIAN NEGATIVE HEIGHT ANOMALY DRIVING MOST OF THE PATTERN ONCE
AGAIN. THERE ARE GROWING INDICATIONS IN THE ECMWF FOR AN EASTWARD
EXTENSION OF THE EAST-ASIAN UPPER JET...WHICH WOULD SUPPORT
SUBSTANTIAL HEIGHT RISES OVER THE EASTERN PAC...AND A STRONGLY
POSITIVE PNA. A STRONG LEADING UPPER TROUGH WOULD BE POSSIBLE WITH
THIS TRANSITION...POSSIBLY SUPPORTING A WINTER STORM FOR THE
REGION. THIS IS HINTED AT IN THE LATEST SUCCESSIVE RUNS OF THE
ECMWF VALID FOR THE END OF NEXT WEEKEND.
MON-WED...SEVERAL NW FLOW IMPULSES EXPECTED...OF WHICH TIMING/
STRENGTH/AND TRACK VARIABILITY REMAINS. HAVE RETAINED LOW TO MID
RANGE POPS THROUGH MOST PERIODS FOR THESE DISTURBANCES...WITH NW
AREAS CONTINUING TO SEE THE BEST CHANCE FOR ANY SNOW ACCUMS...ESP
THE NORTHERN BLACK HILLS. THE MOST PERSISTENT AND STRONGEST
IMPULSE LOOKS TO REMAIN IN THE TUE PERIOD...THUS A POP RAISE WAS
WARRANTED. THE TEMP RANGE ACROSS THE FA WILL REMAIN QUITE LARGE
FROM WEST TO EAST...WITH EASTERN AREAS STRUGGLING TO SCOUR OUT THE
LL COLD AIR MASS.
THUR-SAT...WESTERN CONUS RIDGE WILL SHIFT EAST WITH A WARMER PATTERN
EXPECTED FOR THE FA...AS WESTERLY DOWNSLOPE FLOW PREVAILS. THIS WILL
SUPPORT DRY WEATHER...WITH TEMPS WARMING INTO THE 30S AND 40S WITH
SOME 50S CERTAINLY POSSIBLE IN THE LEE OF THE BLACK HILLS. THE RIDGE
WILL SHIFT EAST SAT...WITH A STRONG UPPER IMPULSE EXPECTED INTO THE
WESTERN CONUS. THIS SUPPORTS LOW POPS SAT ATTM. THE POTENTIAL FOR A
WINTER STORM REMAINS FOR SAT-SUN...GIVEN THE PATTERN SHIFT AND
STRONG LL BAROCLINIC ZONE EXPECTED. THIS WILL BEAR WATCHING.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z SUNDAY EVENING)
ISSUED AT 406 PM MST SAT DEC 28 2013
STRONG GUSTY NORTHWEST WINDS ARE EXPECTED THROUGH THIS
EVENING ON THE SD PLAINS...DIMINISHING OVERNIGHT. AREAS MVFR
CIGS/-SN/--SN ARE EXPECTED THIS EVENING WITH CLEARING SKIES
OVERNIGHT. VFR CONDITIONS SHOULD PREVAIL SUNDAY.
&&
.UNR WATCHES/WARNINGS/ADVISORIES...
SD...WIND CHILL ADVISORY UNTIL 10 AM MST SUNDAY FOR SDZ001-002-
012>014-032-073.
WY...NONE.
&&
$$
UPDATE...HELGESON
SHORT TERM...BUNKERS
LONG TERM...JC
AVIATION...HELGESON
AREA FORECAST DISCUSSION...UPDATED
NWS CORPUS CHRISTI TX
539 AM CST FRI DEC 27 2013
.DISCUSSION...SEE 12Z AVIATION DISCUSSION.
&&
.AVIATION...FOR THE MOST PART...WILL HAVE VFR CIGS FOR THE
DAY...WITH TEMPO MVFR CIGS AND/OR VSBYS WHERE THE RAIN WILL BE
HEAVIER AT TIMES. MOST OF THE RAINFALL SHOULD END BETWEEN 18Z-
22Z...WITH ONLY PATCHY LIGHT RAIN FOR THE REMAINDER OF THE
TERMINAL FORECAST (AND THUS WILL NOT MENTION THIS IN THE
TERMINALS). AM EXPECTING CIGS TO REMAIN VFR OR BETTER AFTER SUNSET
EXCEPT AT KRLD WHERE LIFR CIGS ARE EXPECTED AOA 06Z. WITH LIGHT
NORTH WINDS OVERNIGHT...MAY SEE SOME BR AT KVCT (HAVING IT THIS
MORNING)...BUT SHOULD BE NO WORSE THAN MVFR. NOT EXPECTING FOG AT
KALI OR KCRP. WINDS THOUGH THE PERIOD OVERALL AT ALL TERMINALS
SHOULD BE BELOW 11 KNOTS...ALTHOUGH COULD NOT RULE OUT A BIT
HIGHER WINDS AT KCRP THIS MORNING IF NORTHEAST WINDS REMAIN.
&&
.PREV DISCUSSION... /ISSUED 347 AM CST FRI DEC 27 2013/
SHORT TERM (TODAY THROUGH SATURDAY)...RAIN IS OCCURRING OVER MUCH
OF THE CWA...AND THIS SHOULD CONTINUE THROUGH ABOUT MID MORNING
BEFORE IT BEGINS TO TAPER OFF. HRRR MODEL SHOWING WIDESPREAD LIGHT
RAIN THROUGH ABOUT 15Z...THEN TAPERING OFF LATE IN THE MORNING. THIS
RAIN IS DUE TO UPPER SUPPORT IN THE FORM OF RRQ OF JET AND Q-VECTOR
CONVERGENCE...BOTH OF WHICH WILL BE LESS OF A FACTOR BY THIS EVENING
(SOME WEAK UPGLIDE AS WELL). GUIDANCE IS GOING CHANCE TO LIKELY
POPS...AND SEE NO NEED TO QUARREL WITH THIS. WOULD BE TEMPTED TO GO
EVEN A BIT HIGHER ON POPS SOME AREAS BUT RAIN COULD END OVER SOME
AREAS SHORTLY AFTER 12Z WHEN FORECAST BEGINS. WITH RAIN CHANCES
DIMINISHING BY MID AFTERNOON...AM GOING WITH SLIGHT CHANCE POPS
NORTHEAST (SOME DRY AIR MOVING IN)...WITH CHANCE POPS FARTHER WEST.
RAIN AND CLOUD COVER SHOULD KEEP TEMPERATURES DOWN AGAIN TODAY...AND
AM GOING ON THE LOW SIDE OF GUIDANCE. FOR TONIGHT...MEASURABLE RAIN
SHOULD BE ISOLATED AT BEST WITH RRQ EXITING. HOWEVER...COULD BE WEAK
UPGLIDE WESTERN AREAS TONIGHT AND SOME POSSIBLE LFQ JET DYNAMICS.
FOR SATURDAY...LIGHT RAIN (IF ANY) SHOULD BE RESTRICTED TO THE
COASTAL COUNTIES (AND OFFSHORE) WITH WEAK MOISTURE ADVECTION AND
SOME WEAK DYNAMICS ALOFT. COULD SEE SOME CLEARING SATURDAY
AFTERNOON...SO AM GOING TO GO A BIT WARMER ON THE FORECAST.
MARINE (TODAY THROUGH SATURDAY)...GRADUAL WEAKENING IN NORTHERLY
FLOW THROUGH THE PERIOD...WITH NEAR SCEC FOR THE OFFSHORE GULF OF
MEXICO TODAY. OFFSHORE WINDS EXPECTED TO BE LIGHT BY LATE SATURDAY
WITH HIGH PRESSURE NEAR THE COAST. OTHER THAN LIGHT RAIN...SEE NO
OTHER SIGNIFICANT MARINE ISSUES.
LONG TERM (SATURDAY NIGHT THROUGH THURSDAY NIGHT)...THE EXITING
UPPER LOW WILL ALLOW FOR BRIEF RIDGING ALOFT BY THE LATTER HALF OF
THE WEEKEND WITH SURFACE HIGH BEGINNING TO SHIFT EAST AHEAD OF THE
NEXT UPPER TROUGH. MODELS CONTINUE TO SWING THE UPPER TROUGH EAST AS
IT DIGS ACROSS THE FOUR CORNERS REGION EARLY NEXT WEEK. AGREEMENT
REMAINS WITH THE TIMING OF THE ASSOCIATED COLD FRONT REACHING SOUTH
TEXAS LATE SUNDAY NIGHT INTO EARLY MONDAY MORNING. MOISTURE RETURN
AHEAD OF THE FRONT IS NOT ALL GREAT FOR RAIN CHANCES. HOWEVER
MOISTURE MAY BE ENOUGH ACROSS THE WATERS TO ALLOW FOR ISOLATED
SHOWERS. THE 1040MB HIGH COMING OUT OF CANADA IS EXPECTED TO WEAKEN
A BIT BEFORE REACHING SOUTH TEXAS...MODIFYING EVER SO SLIGHTLY THE
COLD AIRMASS. WITH THIS SAID...DAYTIME TEMPERATURES ARE STILL
EXPECTED TO FALL AND RANGE IN THE 50S MONDAY. CLEARING MONDAY NIGHT
SHOULD LEAD COLD TEMPERATURES MONDAY NIGHT WITH LOWS IN THE 30S WITH
LOCATIONS ACROSS THE NORTHERN CWA REACHING NEAR FREEZING. BY
MIDWEEK...MODELS BEGIN TO DIVERGE WITH SOLUTIONS AS THE EUROPEAN
BREAKS OFF A LOW FROM THE EXITING TROUGH...WHILE THE GFS GENERATES
WEAK MID LEVEL RIDGING. HOWEVER AT THE SURFACE...BOTH SHIFT THE
SURFACE HIGH EAST WITH ONSHORE FLOW REDEVELOPING BRINGING MOISTURE
BACK TO THE REGION. WITH THE ADDITIONAL UPPER SUPPORT...THE EUROPEAN
APPEARS TO BE THE WETTER SOLUTION. HOWEVER TO KEEP SOME CONSISTENCY
UNTIL FURTHER AGREEMENT UPON MODELS...WILL MAINTAIN A MOSTLY DRY
FORECAST WITH ONLY SLIGHT CHANCES FOR LIGHT RAIN WED/THURS.
&&
.PRELIMINARY POINT TEMPS/POPS...
CORPUS CHRISTI 57 46 63 44 69 / 70 20 20 10 10
VICTORIA 61 40 63 41 68 / 40 10 10 10 10
LAREDO 55 47 64 46 70 / 70 20 10 10 10
ALICE 58 45 65 42 69 / 70 20 20 10 10
ROCKPORT 61 46 62 46 65 / 60 10 20 10 10
COTULLA 55 45 64 42 68 / 50 20 10 10 10
KINGSVILLE 57 44 63 42 70 / 70 20 20 10 10
NAVY CORPUS 59 49 62 47 67 / 70 20 20 10 10
&&
.CRP WATCHES/WARNINGS/ADVISORIES...
TX...NONE.
GM...NONE.
&&
$$
GW/86...AVIATION
AREA FORECAST DISCUSSION
NWS CORPUS CHRISTI TX
347 AM CST FRI DEC 27 2013
.SHORT TERM (TODAY THROUGH SATURDAY)...RAIN IS OCCURRING OVER MUCH
OF THE CWA...AND THIS SHOULD CONTINUE THROUGH ABOUT MID MORNING
BEFORE IT BEGINS TO TAPER OFF. HRRR MODEL SHOWING WIDESPREAD LIGHT
RAIN THROUGH ABOUT 15Z...THEN TAPERING OFF LATE IN THE MORNING. THIS
RAIN IS DUE TO UPPER SUPPORT IN THE FORM OF RRQ OF JET AND Q-VECTOR
CONVERGENCE...BOTH OF WHICH WILL BE LESS OF A FACTOR BY THIS EVENING
(SOME WEAK UPGLIDE AS WELL). GUIDANCE IS GOING CHANCE TO LIKELY
POPS...AND SEE NO NEED TO QUARREL WITH THIS. WOULD BE TEMPTED TO GO
EVEN A BIT HIGHER ON POPS SOME AREAS BUT RAIN COULD END OVER SOME
AREAS SHORTLY AFTER 12Z WHEN FORECAST BEGINS. WITH RAIN CHANCES
DIMINISHING BY MID AFTERNOON...AM GOING WITH SLIGHT CHANCE POPS
NORTHEAST (SOME DRY AIR MOVING IN)...WITH CHANCE POPS FARTHER WEST.
RAIN AND CLOUD COVER SHOULD KEEP TEMPERATURES DOWN AGAIN TODAY...AND
AM GOING ON THE LOW SIDE OF GUIDANCE. FOR TONIGHT...MEASURABLE RAIN
SHOULD BE ISOLATED AT BEST WITH RRQ EXITING. HOWEVER...COULD BE WEAK
UPGLIDE WESTERN AREAS TONIGHT AND SOME POSSIBLE LFQ JET DYNAMICS.
FOR SATURDAY...LIGHT RAIN (IF ANY) SHOULD BE RESTRICTED TO THE
COASTAL COUNTIES (AND OFFSHORE) WITH WEAK MOISTURE ADVECTION AND
SOME WEAK DYNAMICS ALOFT. COULD SEE SOME CLEARING SATURDAY
AFTERNOON...SO AM GOING TO GO A BIT WARMER ON THE FORECAST.
&&
.MARINE (TODAY THROUGH SATURDAY)...GRADUAL WEAKENING IN NORTHERLY
FLOW THROUGH THE PERIOD...WITH NEAR SCEC FOR THE OFFSHORE GULF OF
MEXICO TODAY. OFFSHORE WINDS EXPECTED TO BE LIGHT BY LATE SATURDAY
WITH HIGH PRESSURE NEAR THE COAST. OTHER THAN LIGHT RAIN...SEE NO
OTHER SIGNIFICANT MARINE ISSUES.
&&
.LONG-TERM (SATURDAY NIGHT THROUGH THURSDAY NIGHT)...THE EXITING
UPPER LOW WILL ALLOW FOR BRIEF RIDGING ALOFT BY THE LATTER HALF OF
THE WEEKEND WITH SURFACE HIGH BEGINNING TO SHIFT EAST AHEAD OF THE
NEXT UPPER TROUGH. MODELS CONTINUE TO SWING THE UPPER TROUGH EAST AS
IT DIGS ACROSS THE FOUR CORNERS REGION EARLY NEXT WEEK. AGREEMENT
REMAINS WITH THE TIMING OF THE ASSOCIATED COLD FRONT REACHING SOUTH
TEXAS LATE SUNDAY NIGHT INTO EARLY MONDAY MORNING. MOISTURE RETURN
AHEAD OF THE FRONT IS NOT ALL GREAT FOR RAIN CHANCES. HOWEVER
MOISTURE MAY BE ENOUGH ACROSS THE WATERS TO ALLOW FOR ISOLATED
SHOWERS. THE 1040MB HIGH COMING OUT OF CANADA IS EXPECTED TO WEAKEN
A BIT BEFORE REACHING SOUTH TEXAS...MODIFYING EVER SO SLIGHTLY THE
COLD AIRMASS. WITH THIS SAID...DAYTIME TEMPERATURES ARE STILL
EXPECTED TO FALL AND RANGE IN THE 50S MONDAY. CLEARING MONDAY NIGHT
SHOULD LEAD COLD TEMPERATURES MONDAY NIGHT WITH LOWS IN THE 30S WITH
LOCATIONS ACROSS THE NORTHERN CWA REACHING NEAR FREEZING. BY
MIDWEEK...MODELS BEGIN TO DIVERGE WITH SOLUTIONS AS THE EUROPEAN
BREAKS OFF A LOW FROM THE EXITING TROUGH...WHILE THE GFS GENERATES
WEAK MID LEVEL RIDGING. HOWEVER AT THE SURFACE...BOTH SHIFT THE
SURFACE HIGH EAST WITH ONSHORE FLOW REDEVELOPING BRINGING MOISTURE
BACK TO THE REGION. WITH THE ADDITIONAL UPPER SUPPORT...THE EUROPEAN
APPEARS TO BE THE WETTER SOLUTION. HOWEVER TO KEEP SOME CONSISTENCY
UNTIL FURTHER AGREEMENT UPON MODELS...WILL MAINTAIN A MOSTLY DRY
FORECAST WITH ONLY SLIGHT CHANCES FOR LIGHT RAIN WED/THURS.
&&
.PRELIMINARY POINT TEMPS/POPS...
CORPUS CHRISTI 57 46 63 44 69 / 70 20 20 10 10
VICTORIA 61 40 63 41 68 / 40 10 10 10 10
LAREDO 55 47 64 46 70 / 70 20 10 10 10
ALICE 58 45 65 42 69 / 70 20 20 10 10
ROCKPORT 61 46 62 46 65 / 60 10 20 10 10
COTULLA 55 45 64 42 68 / 50 20 10 10 10
KINGSVILLE 57 44 63 42 70 / 70 20 20 10 10
NAVY CORPUS 59 49 62 47 67 / 70 20 20 10 10
&&
.CRP WATCHES/WARNINGS/ADVISORIES...
TX...NONE.
GM...NONE.
&&
$$
GW/86...SHORT TERM
CB/85...LONG TERM
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
1132 PM CST THU DEC 26 2013
.UPDATE...
ISSUED AT 950 PM CST THU DEC 26 2013
SKY FORECAST IS EXTREMELY PROBLEMATIC...RESULTING FROM THE LARGE
CLEARING HOLE THAT HAS DEVELOPED IN CENTRAL MINNESOTA. OVERALL
THERE IS A GENERAL WESTERLY WIND FLOW...WHICH IS ALLOWING THE
CURRENT HIGHER BASED STRATUS OVER THE FORECAST AREA TO PUSH OFF TO
THE EAST. SO IT SEEMS THERE SHOULD BE CLEARING OVER THE NEXT FEW
HOURS BEHIND THIS HIGHER BASED STRATUS. MEANWHILE...THAT SAME
WESTERLY FLOW IS ALLOWING SOME ADVANCEMENT EASTWARD OF THE LOW
STRATUS IN WESTERN AND SOUTH CENTRAL MN. HOWEVER...THAT HOLE
THAT IS IN CENTRAL MINNESOTA IS EXPANDING. NAM/RAP LOW LEVEL RH
PROGS DO NOT HAVE A GOOD HANDLE ON THE SITUATION...BUT SPECIFIC
VALUES WOULD SEEM TO SUGGEST THAT THE STRATUS COMING AT US FROM
WESTERN MN WILL DISSIPATE SOME. AGAIN...NEEDLESS TO SAY A TOUGH
SKY FORECAST.
ON TOP OF THE SKY PROBLEM...IN THAT CLEARING HOLE VISIBILITIES
HAVE DROPPED IN SOME SPOTS TO 1/4 MILE. THIS COULD HAPPEN AS WELL
OVER THE FORECAST AREA WHEN SKIES CLEAR. HAVE INCLUDED PATCHY FOG
OVERNIGHT...BUT WOULD NOT BE SURPRISED IF THIS FOG NEEDS TO BE
EXPANDED IN COVERAGE. THERE IS EVEN AN OUTSIDE CHANCE OF A DENSE
FOG ADVISORY NEED IF SKIES CAN STAY CLEAR.
ON A FINAL NOTE...THE SNOW THAT BECAME ENHANCED A BIT ALONG I-94
IS DIMINISHING...RESULTING FROM A SHORTWAVE PASSAGE ON WATER VAPOR
AND ISENTROPIC DESCENT OCCURRING ON THE 270-275K SURFACES.
&&
.SHORT TERM...(THIS EVENING THROUGH FRIDAY)
ISSUED AT 340 PM CST THU DEC 26 2013
FOR EARLY THIS EVENING...A WEAKENING TROUGH WILL MOVE EAST INTO
EASTERN WISCONSIN. AS THIS OCCURS...THE OMEGA BETWEEN 750 AND
400 MB WILL QUICKLY WANE AND SO WILL THE LIGHT SNOW ALONG THE
INTERSTATE 94 CORRIDOR. LITTLE...IF ANY...ACCUMULATION IS
EXPECTED.
OVERNIGHT...WARM AIR ADVECTION WILL DEVELOP AHEAD OF AN
APPROACHING WARM FRONT MOVING OUT OF THE NORTHERN PLAINS.
850 MB TEMPERATURES WARM FROM AROUND -6C TO 0C BY SUNRISE
FRIDAY. IN ADDITION...OMEGA BETWEEN 600 AND 300 MB WILL RESULT IN
AN INCREASE IN THE MID AND HIGH CLOUDS. EARLIER TODAY...THE BUFKIT
SOUNDINGS WERE SHOWING THE MOISTURE DRAMATICALLY INCREASING BELOW
925 MB. AS A RESULT...THERE WAS SOME CONCERN OF SOME SHALLOW FOG
DEVELOPING ACROSS THE FORECAST AREA. HOWEVER THE LATEST RAP AND
NAM/WRF HAVE STARTED TO BACK AWAY FROM THIS SOLUTION.
ON FRIDAY...A WARM FRONT WILL MOVE QUICKLY EAST ACROSS THE AREA.
925 MB TEMPERATURES WARM FROM AROUND 0C INTO THE 2 TO 6C RANGE BY
SUNSET. THIS WILL RESULT IN HIGH TEMPERATURES WARMING INTO THE
LOWER TO MID 30S WHICH IS ABOUT 10 DEGREES ABOVE NORMAL.
.LONG TERM...(FRIDAY NIGHT THROUGH THURSDAY)
ISSUED AT 340 PM CST THU DEC 26 2013
ON SATURDAY...SOUTHWEST WINDS ALOFT WILL CONTINUE TO ADVECT WARM
AIR INTO THE REGION FROM THE CENTRAL AND SOUTHERN PLAINS. THIS
WILL ALLOW TEMPERATURES TO CLIMB INTO THE MID AND UPPER 30S.
ON SATURDAY NIGHT AND EARLY SUNDAY MORNING...A STRONG ARCTIC COLD
FRONT WILL MOVE QUICKLY SOUTH THROUGH THE FORECAST AREA. WITH MUCH
OF THE FLOW PRECEDING THIS FRONT BEING FROM THE WEST AND
SOUTHWEST...THERE WILL BE VERY LITTLE MOISTURE FOR THIS FRONT TO
WORK WITH. SOUNDINGS SUGGEST THAT AS THE MOISTURE INCREASES IN THE
LOW LEVELS THERE WILL NO ICE CRYSTALS AVAILABLE...BUT THIS QUICKLY
CHANGES ABOUT AN HOUR AFTER PRECIPITATION ONSET. AS A
RESULT...THERE MAY BE A BRIEF PERIOD OF FREEZING DRIZZLE PRIOR TO
THE PRECIPITATION CHANGING OVER TO SNOW. WITH MUCH OF THE FORCING
WITH THE LONG WAVE TROUGH MOVING QUICKLY EAST OF THE AREA...NOT
EXPECTING MUCH SNOW WITH THIS SYSTEM.
ON SUNDAY...STRONG COLD AIR ADVECTION WILL BE SEEN ACROSS THE
AREA. THE INITIAL SURGE WILL CAUSE TEMPERATURES TO FALL INTO THE 5
TO 15 DEGREE RANGE...AND THEN TEMPERATURES WILL STABILIZE FOR THE
REMAINDER OF THE DAY. NORTHWEST WINDS IN THE 15 TO 25 KNOT RANGE
WILL PRODUCE WIND CHILLS IN THE 0 TO 20 BELOW RANGE DURING THE
AFTERNOON. THERE IS ALSO SOME CONCERN THAT THERE MAY BE SOME
BLOWING AND DRIFTING SNOW...BUT THE CONFIDENCE WAS TOO LOW AT THIS
TIME TO BE INCLUDED IN THE FORECAST GRIDS AT THIS TIME. THIS WAS
MAINLY DUE TO THE POSSIBILITY THAT THE COLD AIR COULD POTENTIALLY
LOCK UP THE SNOW IN THE SNOW PACK AND PREVENT IT FROM MOVING.
FROM SUNDAY NIGHT INTO MONDAY MORNING...TEMPERATURES WILL FALL
INTO THE -5 TO 5 DEGREE RANGE AND THE NORTHWEST WINDS WILL REMAIN
IN THE 5 TO 15 KNOT RANGE. THIS WILL PRODUCE WIND CHILLS IN THE
-20 TO -35 DEGREE RANGE ACROSS THE ENTIRE AREA. LIKE THE PAST
COUPLE OF DAYS...EXPECT A WIND CHILL ADVISORY TO BE NEEDED FOR
THIS TIME PERIOD.
FROM MONDAY NIGHT INTO NEW YEARS DAY...ANOTHER ARCTIC COLD FRONT
WILL MOVE THROUGH THE AREA ON MONDAY NIGHT. THIS FRONT WILL BRING
EVEN COLDER AIR INTO THE REGION. THE GEM HAS THE COLDEST
TEMPERATURES WITH LOW TEMPERATURES FALLING INTO -15 TO -25 DEGREE
RANGE ON TUESDAY MORNING AND INTO THE -25 TO -45 DEGREE RANGE ON
WEDNESDAY MORNING. MEANWHILE THE GFS IS THE WARMEST WITH
TEMPERATURES RANGING FROM -5 TO 10F ON TUESDAY MORNING...AND FROM
-5 TO -20F ON WEDNESDAY MORNING. WITH THE ECMWF A FEW DEGREES
COLDER THAN THE MODEL CONSENSUS...WENT A 2 TO 4 DEGREES COLD THAN
THE ALL BLEND TEMPERATURES.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z FRIDAY NIGHT)
ISSUED AT 1132 PM CST THU DEC 26 2013
FOG/MIST REMAINS THE MAIN CONCERN FOR THE TAFS...PARTICULARLY FOR
THIS MORNING. SKIES HAVE CLEARED OUT OVER CENTRAL MINNESOTA AND
THIS CLEARING IS APPROACHING THE TAF SITES. ANTICIPATING BOTH
SITES TO BE CLEAR BY 07Z. THIS CLEARING COMBINED WITH LIGHT WINDS
AND MOISTURE AT THE SURFACE HAS RESULTED IN VARIABLE FOG/MIST
ACROSS CENTRAL MN. VISIBILITIES THERE RANGE FROM VLIFR TO VFR.
BELIEVE SOMETHING SIMILAR WILL HAPPEN AT THE TAF SITES...SO PUT
FOR NOW A RANGE OF MVFR TO IFR. VLIFR CONDITIONS ARE POSSIBLE AS
WELL...BUT CONFIDENCE IS TOO LOW RIGHT NOW TO INCLUDE. THERE ARE
HIGHER CLOUDS DROPPING SOUTH THROUGH MN...AND THESE CLOUDS
COMBINED WITH SOUTHWEST WINDS PICKING UP AROUND 13Z SHOULD HELP TO
GET RID OF ANY FOG/MIST.
OTHERWISE...VFR CONDITIONS ARE ANTICIPATED THROUGH 06Z FRIDAY
NIGHT. THE ONLY OTHER HIGHLIGHT IS WINDS THIS AFTERNOON AS THE
PRESSURE GRADIENT TIGHTENS. WINDS AT RST LOOK TO COME UP TO 15-20
KT WITH SLIGHTLY HIGHER GUSTS...WHILE ONLY COMING UP TO 10-15 KT
AT LSE. A STRONG WIND CORE COMING ACROSS THE TAF SITES BETWEEN
19-23Z RESULTS IN THE NEED FOR LOW LEVEL WIND SHEAR AT LSE. THE
WIND DIFFERENCE IS NOT HIGH ENOUGH TO MENTION AT RST.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
UPDATE...AJ
SHORT TERM...BOYNE
LONG TERM...BOYNE
AVIATION...AJ
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
349 AM CST SUN DEC 29 2013
.DISCUSSION...
922 PM CST
GOING FORECAST FOR TONIGHT IS IN GOOD SHAPE. MAIN TWEAK WAS TO
BUMP UP SKY COVER THIS EVENING WITH CIRRUS CONTINUING TO STREAM
NORTHWARD. WINDS REMAIN ELEVATED OUT OF THE SOUTHWEST BUT WITH
PRESSURE FALLS NOT QUITE AS IMPRESSIVE AS LAST NIGHT...MOST
LOCATIONS HAVE SEEN STEADY OR SLOWLY FALLING TEMPERATURES INSTEAD
OF RISING. DO NOT FORESEE NEEDING TO MAKE BIG CHANGES TO THE LOW
TEMPERATURE FORECAST.
POWERFUL COLD FRONT TRAILING FROM LOW PRESSURE OVER WEST CENTRAL
WISCONSIN STILL ON TRACK TO CROSS THE CWA FROM BEFORE DAYBREAK IN
THE NORTHWEST TO MID MORNING IN THE SOUTHEAST. FALLING
TEMPERATURES AND WINDS GUSTING TO OVER 30 MPH WILL PROVIDE A SLAP
OF WINTER REALITY AFTER THE MILD WEATHER TODAY. WIND CHILL VALUES BY
NIGHTFALL TOMORROW AFTERNOON WILL RANGE FROM AROUND 5 TO 10 BELOW IN
THE NORTHWEST TO 10 ABOVE IN THE SOUTHEAST...WITH SINGLE DIGITS IN
DOWNTOWN CHICAGO. A WIND CHILL ADVISORY WILL LIKELY BE NEEDED FOR AT
LEAST PARTS OF THE AREA TOMORROW NIGHT.
THE SET-UP FOR LIGHT SNOW BEHIND THE FRONT IS NOT TOO IMPRESSIVE
WITH A SHALLOW MOIST LAYER BENEATH AN INVERSION ON FORECAST
SOUNDINGS. COULD BE A SITUATION WITH SCATTERED SNOW SHOWERS THAT MAY
PUT DOWN ISOLATED DUSTINGS TO PERHAPS UP TO A HALF INCH IN SOME
SPOTS WHILE MOST OF THE REMAINDER OF THE AREA SEES FLURRIES AND
NO ACCUMULATION. DID NOT MAKE ANY CHANGES BUT WILL PASS ON
CONCERNS TO MIDNIGHT SHIFT.
UPDATED ZFP WILL BE SENT SHORTLY.
RC
//PREV DISCUSSION...
258 PM...MULTIPLE FORECAST CONCERNS CONTINUE THROUGH THE PERIOD
WITH VERY COLD AIR SPREADING BACK ACROSS THE AREA SUNDAY...ALONG
WITH A PERIOD OF LIGHT SNOW. THEN VARIOUS WAVES NEXT WEEK...EACH
WITH THE CHANCE OF ACCUMULATING SNOW...AND CONTINUED BELOW NORMAL
TEMPS.
IN THE SHORT TERM...TEMPS HAVE WARMED INTO THE LOWER TO MID 50S
SOUTH OF THE SNOW PACK UNDER SUNNY SKIES THIS AFTERNOON. WHILE
SOUTHWESTERLY WINDS WILL NOT BE AS STRONG THIS EVENING AS THEY
WERE FRIDAY EVENING...ONCE TEMPS QUICKLY DROP BACK INTO THE LOWER
40S AFTER SUNSET...THEY SHOULD THEN ONLY SLOWLY FALL INTO THE 30S
BY LATE EVENING...ALLOWING FOR ONE LAST MILD EVENING.
LOW PRESSURE OVER SOUTHERN MINNESOTA WILL MOVE EAST ACROSS LAKE
MICHIGAN EARLY SUNDAY MORNING...WITH A STRONG TRAILING COLD FRONT
MOVING ACROSS THE CWA BY MID MORNING SUNDAY. POSSIBLE THAT TEMPS
MAY WARM A FEW DEGREES ACROSS THE EASTERN AREAS AHEAD OF THE FRONT
BUT FOR MUCH OF THE AREA...HIGH TEMPS WILL OCCUR AHEAD OF FROPA
WITH FALLING TEMPS FOR THE REMAINDER OF THE DAY. THESE FALLING
TEMPS COMBINED WITH NORTHWEST WINDS 15-25 MPH WILL PUSH WIND
CHILLS DOWN INTO THE SINGLE DIGITS IN THE AFTERNOON AND BELOW ZERO
AFTER SUNSET. LOWS BY MONDAY MORNING WILL LIKELY RANGE FROM -5 TO
-10 OVER THE SNOW PACK AND COMBINED WITH CONTINUED NORTHWEST WINDS
IN THE 10-15 MPH RANGE...WIND CHILLS WILL LIKELY REACH ADVISORY
LEVEL...-20...MID/LATE SUNDAY EVENING ACROSS THE NORTHWEST CWA
WITH ADVISORY LEVEL WIND CHILLS OVER MUCH OF THE NORTHERN HALF TO
NORTHERN TWO THIRDS OF THE CWA OVERNIGHT INTO MONDAY MORNING AND
A WIND CHILL ADVISORY WILL LIKELY BE NEEDED FOR THIS TIME PERIOD
WITH LATER FORECASTS.
AS THE COLDER AIR SPREADS IN BEHIND THE COLD FRONT...THE LOW
LEVELS SATURATE FAIRLY QUICKLY AND AS A WEAK UPPER LEVEL WAVE
SPREADS ACROSS THE AREA...EXPECT A PERIOD OF LIGHT SNOW TO DEVELOP
BY MID MORNING...PERHAPS MORE SHOWERY AT TIMES...AND QUICKLY MOVE
EAST ACROSS THE AREA THROUGH MID/LATE AFTERNOON. MODEL QPF AMOUNTS
ARE ONLY A FEW HUNDREDTHS OF AN INCH...SO NOT EXPECTING MUCH
ACCUMULATION...BUT SNOW MAY START SOMEWHAT WETTER IN THE 12:1
RATIO RANGE AND END MUCH DRIER. HAVE MAINTAINED PATCHY BLOWING
SNOW FROM PREVIOUS FORECAST BUT WITH SUCH LITTLE AMOUNTS...MIGHT
END UP BEING MORE LOW DRIFTING THAN BLOWING. CLOUDS LINGER INTO
THE EVENING WITH A CHANCE FLURRIES...ALL ENDING IN THE LATE
EVENING.
THE MODELS REMAIN IN FAIR AGREEMENT WITH ONE CLIPPER SYSTEM MOVING
ACROSS THE REGION MONDAY NIGHT AND A SECOND LATE TUESDAY AFTERNOON
INTO TUESDAY NIGHT. GIVEN THE CONSISTENCY OVER THE PAST FEW DAYS...
HAVE INCLUDED LIKELY POPS ACROSS THE FAR NORTH MONDAY NIGHT AND
THEN LIKELY POPS ALL AREAS TUESDAY NIGHT. THE AIRMASS WILL REMAIN
VERY COLD...BUT WITH CLOUDS/SNOW...ACTUAL HIGHS/LOWS AND TEMP
TRENDS IS RATHER UNCERTAIN. WITH THE INCREASE IN POPS...ALSO
BUMPED UP TEMPS SOME. AND TIMING WILL BE EVERYTHING...SHOULD SNOW
FALL AT NIGHT...LOWS COULD BE WARMER...IF THE SNOW FALLS DURING
THE DAY...HIGHS COULD BE WARMER...WITH COLD AIR PUNCHING BACK INTO
THE AREA AT NIGHT. THIS DECREASE IN CONFIDENCE REGARDING TEMPS
ALSO DECREASES CONFIDENCE IN SNOW/WATER RATIOS. SOME OF THE COBB
OUTPUT WOULD SUGGEST 20:1 TO 25:1 WHICH IS CERTAINLY POSSIBLE BUT
FROM THIS DISTANCE HAVE GONE MORE MIDDLE OF THE ROAD IN THE 15:1
RANGE. COMBINE THIS UNCERTAINTY WITH QPF AMOUNTS...ITS TOO EARLY
FOR SPECIFIC AMOUNTS...BUT CURRENT TRENDS WOULD SUPPORT AN INCH OR
SO NORTH MONDAY NIGHT AND A FEW TO SEVERAL INCHES TUESDAY NIGHT.
A BIT LARGER CLIPPER/STORM SYSTEM COULD POTENTIALLY AFFECT THE
AREA THURSDAY INTO THURSDAY NIGHT. ALL OF THE MODELS HAVE THIS
FEATURE...TO SOME EXTENT BUT HAVE OPTED TO MAINTAIN LOW CHANCE
POPS FOR NOW. BUT SOME ACCUMULATION WOULD BE POSSIBLE WITH THIS
SYSTEM AND WITH THE POTENTIAL FOR A FRESH SNOW PACK ACROSS THE
ENTIRE AREA BY THIS TIME...HAVE CONTINUED WITH LOWER TEMPS
THURSDAY NIGHT INTO FRIDAY. CMS
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 09Z...
* WIND SHIFT TO WNW TOWARD DAWN THEN BECOMING NW AND GUSTY BE MID
MORNING.
* MVFR CIGS SPREAD ACROSS LOCAL AREA WITHIN 1-2 HRS FOLLOWING
FROPA...PERIODS OF IFR CIGS FROM MID MORNING TO EARLY AFTERNOON.
* PERIODS OF FLURRIES AND LIGHT SNOW LATE MORNING THROUGH MID
AFTERNOON AND COULD REDUCE VSBY TO MVFR CAT.
* STRONG GUSTY NW WIND MID MORNING INTO EARLY EVE WILL CAUSE
DRIFTING ACROSS RUNWAYS...TAXIWAYS AND RAMPS THOUGH TOTAL
SNOWFALL EXPECTED TO BE ONLY A FEW TENTHS OF AN IN AT MOST.
TRS
//DISCUSSION...UPDATED 06Z...
LATE MODEL OUTPUT ALL HAVE FROPA OCCURRING AT ORD AND MDW RIGHT
AROUND 12Z ALTHOUGH THIS WILL BE MARKED FIRST BY A WSHFT TO OUT
OF THE W-WNW...AND THE A COUPLE HRS LATER VEERING TO NW-NNW
GUSTING 25-30KT AFTER THE 850HPA TROUGH PASSES BY 15Z-16Z AND THE
700HPA LEVEL TROUGH 17Z-19Z. UPSTREAM THERE CURRENTLY IS AN AREA
OF MAINLY MVFR CIGS...WITH AREAS OF IFR...BEHIND THIS SECOND
SHIFT AND BASED ON FORECAST LOW LEVEL RH PROGS SUSPECT THEY WILL
BE ARRIVING LOCALLY WITH THE WIND VEERING OF WINDS 13Z- 15Z.
INITIALLY NOT MUCH MOISTURE AVAILABLE FOR PRECIP BUT PROGS DO
SHOW INCREASING MID AND UPPER LEVEL MOISTURE MID MORNING INTO
EARLY AFTERNOON. WITH STRONG COLD AIR ADVECTION SPREADING SE AND
ACROSS THE AREA AS WELL AS ANOTHER MINOR MID LEVEL SHORT WAVE
TROUGH APPROACHING THE AREA THIS MORNING AND MOVING OVER HEAD BY
LATE AFTERNOON ANTICIPATE MAINLY FLURRIES OR VERY LIGHT SNOW BUT
WITH A PERIOD OF SLIGHTLY HEAVIER LIGHT SNOW ASSOCIATED WITH THE
SECOND SHORT WAVE.
NW WIND TO BE DROPPING LATE AFTERNOON AND THIS EVE WITH AS
LESSENING OF THE GRADIENT AS LOW PRESSURE MOVES FURTHER E TO N OF
LAKE ONTARIO BY 00Z AND A LARGE AREA OF HIGH PRESSURE BUILDING SE
OVER THE PLAINS TODAY THEN MOVES E TO THE UPPER MIDWEST AND MID
MS VALLEY BY 12Z MON.
TRS
//ORD AND MDW CONFIDENCE...UPDATED 09Z...
* HIGH CONFIDENCE IN OVER ALL TRENDS.
* MEDIUM CONFIDENCE IN TIMING +/- 1HR OF FROPA...SECONDARY WSHFT
AND AND ARRIVAL OF MVFR AND IFR CIGS.
* HIGH CONFIDENCE IN OCCURRENCE OF SNOW FLURRIES OR VERY LIGHT
SNOW...MEDIUM CONFIDENCE SLIGHTLY HEAVIER LIGHT SNOW MIDDAY AND
EARLY AFTERNOON.
TRS
//OUTLOOK FOR ORD/MDW FOR 12Z MONDAY-12Z SATURDAY...UPDATED 00Z...
MONDAY...VFR.
MONDAY NIGHT...CHANCE OF -SN AND IFR.
TUESDAY...CHANCE OF MVFR CIGS.
TUESDAY NIGHT...SNOW AND IFR FAIRLY LIKELY.
WEDNESDAY...MVFR CIGS POSSIBLE.
THURSDAY AND FRIDAY...SOME POTENTIAL FOR SNOW AND IFR...BUT LOW
CONFIDENCE.
IZZI
&&
.MARINE...
400 PM CST
LOW PRESSURE OVER THE EASTERN DAKOTAS WILL TRACK EAST ACROSS THE
FAR NORTHERN TIP OF LAKE MICHIGAN TONIGHT AND CONTINUE EAST
TO SOUTHERN QUEBEC SUNDAY NIGHT WHILE DRAGGING A STRONG COLD FRONT
DOWN THE LENGTH OF THE LAKE. AHEAD OF THE FRONT THIS EVENING...A
MODERATE SOUTHWESTERLY GRADIENT WILL KEEP WINDS ARND 15-25KT.
FOLLOWING THE FRONTAL PASSAGE...VERY COLD AIR WILL FILTER IN OVER
THE LAKE OVERNIGHT TONIGHT AS STRONG HIGH PRESSURE BUILDS ACROSS
THE CENTRAL PLAINS. THE COMBINATION OF THE VERY STRONG COLD
ADVECTION AND STRONG PRESSURE GRADIENT WILL LEAD TO NORTHWEST TO
NORTH GALES DEVELOPING...INITIALLY OVER THE NORTHERN PORTIONS OF
THE LAKE DURING THE EARLY MORNING HOURS. GALES WILL QUICKLY SPREAD
DOWN THE REMAINDER OF THE LAKE EARLY SUNDAY MORNING. THE VERY COLD
AIR...STRONG WINDS AND HIGH WAVES WILL LEAD TO THE POTENTIAL FOR
MODERATE TO HEAVY FREEZING SPRAY...WITH THE GREATEST CHANCE FOR
HEAVY FREEZING SPRAY TO OCCUR DURING THE PERIOD OF THE GALE
WARNING...THOUGH SOME HEAVY SPRAY POTENTIAL COULD STILL LINGER AS
WINDS DROP BELOW GALE FORCE DUE TO THE SLOW DECLINE IN WIND
HEIGHTS AND THE ADVECTION OF COLDER AIR WELL BEHIND THE FRONTAL
BOUNDARY. FOR THE NEARSHORE WATERS...THE BETTER CHANGE FOR GALES
WILL BE OVER THE INDIANA WATERS DUE TO THE DIRECT NORTH TO
NORTHWEST FETCH PREDOMINANTLY OVER ALL WATER...WHILE THE ILLINOIS
NEARSHORE WATERS SHOULD REMAIN BELOW GALE FORCE DUE TO SLIGHTLY
WEAKER FLOW OFF LAND. WINDS AND WAVES WILL DIMINISH AS THE HIGH
SPREADS EAST MONDAY NIGHT AND TUESDAY...BUT ANOTHER LOW IS
EXPECTED TO DEVELOP OVER THE NORTHERN PLAINS MONDAY MORNING AND
TRACK EAST ACROSS NORTHERN ILLINOIS MONDAY NIGHT AND THEN CONTINUE
TO THE EASTERN GREAT LAKES TUESDAY MORNING. AS YET ANOTHER ARCTIC
HIGH PRESSURE SYSTEM BUILDS INTO THE NORTHERN PLAINS TUESDAY
NIGHT...STRONG NORTHWEST WINDS WILL DEVELOP AGAIN FOR TUESDAY AND
TUESDAY NIGHT...BUT THIS SYSTEM SHOULD BE ACCOMPANIED BY A WEAKER
PRESSURE GRADIENT AND THE AIRMASS WILL NOT BE QUITE AS COLD...SO
ANOTHER ROUND GALES AND FREEZING SPRAY IS NOT ANTICIPATED AT THIS
TIME.
KREIN
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...WIND CHILL ADVISORY...ILZ003-ILZ004-ILZ005-ILZ006-ILZ008-ILZ010-
ILZ011-ILZ012-ILZ019-ILZ020-ILZ021-ILZ032...9 PM SUNDAY TO
NOON MONDAY.
IN...NONE.
LM...GALE WARNING...LMZ080-LMZ567-LMZ669-LMZ671-LMZ673-LMZ675-LMZ744-
LMZ745-LMZ777-LMZ779-LMZ868-LMZ870-LMZ872-LMZ874-LMZ876-
LMZ878...9 AM SUNDAY TO 9 PM SUNDAY.
HEAVY FREEZING SPRAY WARNING...LMZ080-LMZ567-LMZ669-LMZ671-
LMZ673-LMZ675-LMZ740-LMZ741-LMZ742-LMZ743-LMZ744-LMZ745-
LMZ777-LMZ779-LMZ868-LMZ870-LMZ872-LMZ874-LMZ876-LMZ878...9
AM SUNDAY TO MIDNIGHT MONDAY.
GALE WARNING...LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-LMZ565 UNTIL 6
PM SUNDAY.
HEAVY FREEZING SPRAY WARNING...LMZ261-LMZ362-LMZ364-LMZ366-
LMZ563-LMZ565 UNTIL MIDNIGHT MONDAY.
SMALL CRAFT ADVISORY...LMZ740-LMZ741-LMZ742-LMZ743...9 AM SUNDAY
TO 4 AM MONDAY.
&&
$$
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[top]
Area Forecast Discussion
National Weather Service Lincoln IL
330 AM CST Sun Dec 29 2013
.DISCUSSION...
ISSUED 330 AM CST Sun Dec 29 2013
Will issue a wind chill advisory for northern 10 counties from 9
pm this evening until 9 am Monday morning for wind chills of 15 to
20 below zero. The wind chill advisory is roughly along and north
of a Rushville to Bloomington line.
SHORT TERM...Today through Tuesday night
Arctic cold front extends from 1005 mb low pressure over northern
lower MI through southeast WI into NW IL (recently passing se of
Galesburg) and into central MO. Relatively mild temps in the mid
to upper 30s over central and southeast IL with 41F at Robinson.
Area of light rain over far southeast IL (along and southeast of a
Robinson to Flora line) and into KY/TN and southern IN and
associated with isentropic lift ahead of weakening 558 dm 500 mb
low over the red river valley along the OK/Texas border. This
upper level low to continue to weaken/open up as it ejects into
the TN valley today taking its light rain out of IL early this
morning. Main weather story today will be strong arctic cold front
that quickly sweeps se through central IL through mid morning and
passes se of the Wabash river late this morning. Expect temps to
drop behind the cold front with brisk/gusty nw winds behind front
as temps fall to 10F at Galesburg by sunset and near 30F by
Lawrenceville in far southeast IL. NAM models remains dry today
but some other high res models like RAP, HRRR and SREF show
patches of light qpf over mainly northern counties from 15Z-22Z
today. Mainly think scattered flurries with a few light snow
showers possible over mainly northern counties today and not
expecting any accumulations.
Clouds decrease tonight and very cold lows in the single digits
below zero over IL river valley where wind chills reach 15 to 20
below zero by late evening until around 9 am Monday morning. Will
issue a wind chill advisory as stated earlier. Clouds to increase
from nw during Monday and quite cold with highs in the teens over
central IL and lower 20s in southeast IL. A northern stream short
wave to bring chance of light snow to northern areas Monday night.
With another one bringing chances of light snow to northern areas
Tue afternoon and over much of area Tue night with some light snow
accumulations possible mainly north of I-74. Temps to stay well
below normal into the middle of the week.
LONG TERM...Wednesday through Sunday
Medium to long range forecast models and ensembles continue to
show a strong upper level trof digging back into the MS river
valley Wednesday night and Thursday...and models trending with a
deepening surface low pressure ejecting from the central plains
into the Ohio river valley by Thursday morning. Accumulating snows
appear more likely now to fall north of this low pressure track
over central IL and increased pops north Wednesday and across area
Wed night, and best chances of snow shifting east of IL during
Thursday. Trended temperatures colder behind this storm system Thu
night and Friday as below normal temps continue. Large upper level
trof shifts east of IL Fri/Sat with temps moderating closer to
normal next weekend.
07
&&
.AVIATION...
ISSUED 1149 PM CST Sat Dec 28 2013
A strong cold front is continuing to approach the central Illinois
terminals from the northwest. Until the front gets here, high
level VFR cigs and southwest winds around 10 kts are likely. The
front should move across the area between 11Z and 14Z. Winds are
expected to swing to the northwest and gust to at least 20 kts
behind the front, and low end MVFR cigs will spread across the
area. Added a 2 hour tempo for IFR cigs behind the front at KPIA
and KBMI based on upstream observations and HRRR cloud progs. Little/no
precipitation is anticipated with fropa. Winds will slowly die off
Sunday night. Skies may also begin to scatter our, but have left
MVFR cigs in place for now as the clearing appears too rapid.
Bak
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
WIND CHILL ADVISORY from 9 PM this evening to 9 AM CST Monday
FOR ILZ027>031-036>038-040-041.
&&
$$
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
109 AM CST SUN DEC 29 2013
.DISCUSSION...
922 PM CST
GOING FORECAST FOR TONIGHT IS IN GOOD SHAPE. MAIN TWEAK WAS TO
BUMP UP SKY COVER THIS EVENING WITH CIRRUS CONTINUING TO STREAM
NORTHWARD. WINDS REMAIN ELEVATED OUT OF THE SOUTHWEST BUT WITH
PRESSURE FALLS NOT QUITE AS IMPRESSIVE AS LAST NIGHT...MOST
LOCATIONS HAVE SEEN STEADY OR SLOWLY FALLING TEMPERATURES INSTEAD
OF RISING. DO NOT FORESEE NEEDING TO MAKE BIG CHANGES TO THE LOW
TEMPERATURE FORECAST.
POWERFUL COLD FRONT TRAILING FROM LOW PRESSURE OVER WEST CENTRAL
WISCONSIN STILL ON TRACK TO CROSS THE CWA FROM BEFORE DAYBREAK IN
THE NORTHWEST TO MID MORNING IN THE SOUTHEAST. FALLING
TEMPERATURES AND WINDS GUSTING TO OVER 30 MPH WILL PROVIDE A SLAP
OF WINTER REALITY AFTER THE MILD WEATHER TODAY. WIND CHILL VALUES BY
NIGHTFALL TOMORROW AFTERNOON WILL RANGE FROM AROUND 5 TO 10 BELOW IN
THE NORTHWEST TO 10 ABOVE IN THE SOUTHEAST...WITH SINGLE DIGITS IN
DOWNTOWN CHICAGO. A WIND CHILL ADVISORY WILL LIKELY BE NEEDED FOR AT
LEAST PARTS OF THE AREA TOMORROW NIGHT.
THE SET-UP FOR LIGHT SNOW BEHIND THE FRONT IS NOT TOO IMPRESSIVE
WITH A SHALLOW MOIST LAYER BENEATH AN INVERSION ON FORECAST
SOUNDINGS. COULD BE A SITUATION WITH SCATTERED SNOW SHOWERS THAT MAY
PUT DOWN ISOLATED DUSTINGS TO PERHAPS UP TO A HALF INCH IN SOME
SPOTS WHILE MOST OF THE REMAINDER OF THE AREA SEES FLURRIES AND
NO ACCUMULATION. DID NOT MAKE ANY CHANGES BUT WILL PASS ON
CONCERNS TO MIDNIGHT SHIFT.
UPDATED ZFP WILL BE SENT SHORTLY.
RC
//PREV DISCUSSION...
258 PM...MULTIPLE FORECAST CONCERNS CONTINUE THROUGH THE PERIOD
WITH VERY COLD AIR SPREADING BACK ACROSS THE AREA SUNDAY...ALONG
WITH A PERIOD OF LIGHT SNOW. THEN VARIOUS WAVES NEXT WEEK...EACH
WITH THE CHANCE OF ACCUMULATING SNOW...AND CONTINUED BELOW NORMAL
TEMPS.
IN THE SHORT TERM...TEMPS HAVE WARMED INTO THE LOWER TO MID 50S
SOUTH OF THE SNOW PACK UNDER SUNNY SKIES THIS AFTERNOON. WHILE
SOUTHWESTERLY WINDS WILL NOT BE AS STRONG THIS EVENING AS THEY
WERE FRIDAY EVENING...ONCE TEMPS QUICKLY DROP BACK INTO THE LOWER
40S AFTER SUNSET...THEY SHOULD THEN ONLY SLOWLY FALL INTO THE 30S
BY LATE EVENING...ALLOWING FOR ONE LAST MILD EVENING.
LOW PRESSURE OVER SOUTHERN MINNESOTA WILL MOVE EAST ACROSS LAKE
MICHIGAN EARLY SUNDAY MORNING...WITH A STRONG TRAILING COLD FRONT
MOVING ACROSS THE CWA BY MID MORNING SUNDAY. POSSIBLE THAT TEMPS
MAY WARM A FEW DEGREES ACROSS THE EASTERN AREAS AHEAD OF THE FRONT
BUT FOR MUCH OF THE AREA...HIGH TEMPS WILL OCCUR AHEAD OF FROPA
WITH FALLING TEMPS FOR THE REMAINDER OF THE DAY. THESE FALLING
TEMPS COMBINED WITH NORTHWEST WINDS 15-25 MPH WILL PUSH WIND
CHILLS DOWN INTO THE SINGLE DIGITS IN THE AFTERNOON AND BELOW ZERO
AFTER SUNSET. LOWS BY MONDAY MORNING WILL LIKELY RANGE FROM -5 TO
-10 OVER THE SNOW PACK AND COMBINED WITH CONTINUED NORTHWEST WINDS
IN THE 10-15 MPH RANGE...WIND CHILLS WILL LIKELY REACH ADVISORY
LEVEL...-20...MID/LATE SUNDAY EVENING ACROSS THE NORTHWEST CWA
WITH ADVISORY LEVEL WIND CHILLS OVER MUCH OF THE NORTHERN HALF TO
NORTHERN TWO THIRDS OF THE CWA OVERNIGHT INTO MONDAY MORNING AND
A WIND CHILL ADVISORY WILL LIKELY BE NEEDED FOR THIS TIME PERIOD
WITH LATER FORECASTS.
AS THE COLDER AIR SPREADS IN BEHIND THE COLD FRONT...THE LOW
LEVELS SATURATE FAIRLY QUICKLY AND AS A WEAK UPPER LEVEL WAVE
SPREADS ACROSS THE AREA...EXPECT A PERIOD OF LIGHT SNOW TO DEVELOP
BY MID MORNING...PERHAPS MORE SHOWERY AT TIMES...AND QUICKLY MOVE
EAST ACROSS THE AREA THROUGH MID/LATE AFTERNOON. MODEL QPF AMOUNTS
ARE ONLY A FEW HUNDREDTHS OF AN INCH...SO NOT EXPECTING MUCH
ACCUMULATION...BUT SNOW MAY START SOMEWHAT WETTER IN THE 12:1
RATIO RANGE AND END MUCH DRIER. HAVE MAINTAINED PATCHY BLOWING
SNOW FROM PREVIOUS FORECAST BUT WITH SUCH LITTLE AMOUNTS...MIGHT
END UP BEING MORE LOW DRIFTING THAN BLOWING. CLOUDS LINGER INTO
THE EVENING WITH A CHANCE FLURRIES...ALL ENDING IN THE LATE
EVENING.
THE MODELS REMAIN IN FAIR AGREEMENT WITH ONE CLIPPER SYSTEM MOVING
ACROSS THE REGION MONDAY NIGHT AND A SECOND LATE TUESDAY AFTERNOON
INTO TUESDAY NIGHT. GIVEN THE CONSISTENCY OVER THE PAST FEW DAYS...
HAVE INCLUDED LIKELY POPS ACROSS THE FAR NORTH MONDAY NIGHT AND
THEN LIKELY POPS ALL AREAS TUESDAY NIGHT. THE AIRMASS WILL REMAIN
VERY COLD...BUT WITH CLOUDS/SNOW...ACTUAL HIGHS/LOWS AND TEMP
TRENDS IS RATHER UNCERTAIN. WITH THE INCREASE IN POPS...ALSO
BUMPED UP TEMPS SOME. AND TIMING WILL BE EVERYTHING...SHOULD SNOW
FALL AT NIGHT...LOWS COULD BE WARMER...IF THE SNOW FALLS DURING
THE DAY...HIGHS COULD BE WARMER...WITH COLD AIR PUNCHING BACK INTO
THE AREA AT NIGHT. THIS DECREASE IN CONFIDENCE REGARDING TEMPS
ALSO DECREASES CONFIDENCE IN SNOW/WATER RATIOS. SOME OF THE COBB
OUTPUT WOULD SUGGEST 20:1 TO 25:1 WHICH IS CERTAINLY POSSIBLE BUT
FROM THIS DISTANCE HAVE GONE MORE MIDDLE OF THE ROAD IN THE 15:1
RANGE. COMBINE THIS UNCERTAINTY WITH QPF AMOUNTS...ITS TOO EARLY
FOR SPECIFIC AMOUNTS...BUT CURRENT TRENDS WOULD SUPPORT AN INCH OR
SO NORTH MONDAY NIGHT AND A FEW TO SEVERAL INCHES TUESDAY NIGHT.
A BIT LARGER CLIPPER/STORM SYSTEM COULD POTENTIALLY AFFECT THE
AREA THURSDAY INTO THURSDAY NIGHT. ALL OF THE MODELS HAVE THIS
FEATURE...TO SOME EXTENT BUT HAVE OPTED TO MAINTAIN LOW CHANCE
POPS FOR NOW. BUT SOME ACCUMULATION WOULD BE POSSIBLE WITH THIS
SYSTEM AND WITH THE POTENTIAL FOR A FRESH SNOW PACK ACROSS THE
ENTIRE AREA BY THIS TIME...HAVE CONTINUED WITH LOWER TEMPS
THURSDAY NIGHT INTO FRIDAY. CMS
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 06Z...
* WIND SHIFT TO WNW TOWARD DAWN THEN BECOMING NW AND GUSTY BE MID
MORNING.
* MVFR CIGS SPREAD ACROSS LOCAL AREA WITHIN 1-2 HRS FOLLOWING
FROPA...PERIODS OF IFR CIGS FROM MID MORNING TO EARLY AFTERNOON.
* PERIODS OF FLURRIES AND LIGHT SNOW LATE MORNING THROUGH MID
AFTERNOON AND COULD REDUCE VSBY TO MVFR CAT.
* STRONG GUSTY NW WIND MID MORNING INTO EARLY EVE WILL CAUSE
DRIFTING ACROSS RUNWAYS...TAXIWAYS AND RAMPS THOUGH TOTAL
SNOWFALL EXPECTED TO BE ONLY A FEW TENTHS OF AN IN AT MOST.
TRS
//DISCUSSION...UPDATED 06Z...
LATE MODEL OUTPUT ALL HAVE FROPA OCCURRING AT ORD AND MDW RIGHT
AROUND 12Z ALTHOUGH THIS WILL BE MARKED FIRST BY A WSHFT TO OUT
OF THE W-WNW...AND THE A COUPLE HRS LATER VEERING TO NW-NNW
GUSTING 25-30KT AFTER THE 850HPA TROUGH PASSES BY 15Z-16Z AND THE
700HPA LEVEL TROUGH 17Z-19Z. UPSTREAM THERE CURRENTLY IS AN AREA
OF MAINLY MVFR CIGS...WITH AREAS OF IFR...BEHIND THIS SECOND
SHIFT AND BASED ON FORECAST LOW LEVEL RH PROGS SUSPECT THEY WILL
BE ARRIVING LOCALLY WITH THE WIND VEERING OF WINDS 13Z- 15Z.
INITIALLY NOT MUCH MOISTURE AVAILABLE FOR PRECIP BUT PROGS DO
SHOW INCREASING MID AND UPPER LEVEL MOISTURE MID MORNING INTO
EARLY AFTERNOON. WITH STRONG COLD AIR ADVECTION SPREADING SE AND
ACROSS THE AREA AS WELL AS ANOTHER MINOR MID LEVEL SHORT WAVE
TROUGH APPROACHING THE AREA THIS MORNING AND MOVING OVER HEAD BY
LATE AFTERNOON ANTICIPATE MAINLY FLURRIES OR VERY LIGHT SNOW BUT
WITH A PERIOD OF SLIGHTLY HEAVIER LIGHT SNOW ASSOCIATED WITH THE
SECOND SHORT WAVE.
NW WIND TO BE DROPPING LATE AFTERNOON AND THIS EVE WITH AS
LESSENING OF THE GRADIENT AS LOW PRESSURE MOVES FURTHER E TO N OF
LAKE ONTARIO BY 00Z AND A LARGE AREA OF HIGH PRESSURE BUILDING SE
OVER THE PLAINS TODAY THEN MOVES E TO THE UPPER MIDWEST AND MID
MS VALLEY BY 12Z MON.
TRS
//ORD AND MDW CONFIDENCE...UPDATED 00Z...
* HIGH CONFIDENCE IN OVER ALL TRENDS.
* MEDIUM CONFIDENCE IN TIMING +/- 1HR OF FROPA...SECONDARY WSHFT
AND AND ARRIVAL OF MVFR AND IFR CIGS.
* HIGH CONFIDENCE IN OCCURRENCE OF SNOW FLURRIES OR VERY LIGHT
SNOW...MEDIUM CONFIDENCE SLIGHTLY HEAVIER LIGHT MIDDAY-EARLY
AFTERNOON.
TRS
//OUTLOOK FOR ORD/MDW FOR 12Z MONDAY-12Z SATURDAY...UPDATED 00Z...
MONDAY...VFR.
MONDAY NIGHT...CHANCE OF -SN AND IFR.
TUESDAY...CHANCE OF MVFR CIGS.
TUESDAY NIGHT...SNOW AND IFR FAIRLY LIKELY.
WEDNESDAY...MVFR CIGS POSSIBLE.
THURSDAY AND FRIDAY...SOME POTENTIAL FOR SNOW AND IFR...BUT LOW
CONFIDENCE.
IZZI
&&
.MARINE...
400 PM CST
LOW PRESSURE OVER THE EASTERN DAKOTAS WILL TRACK EAST ACROSS THE
FAR NORTHERN TIP OF LAKE MICHIGAN TONIGHT AND CONTINUE EAST
TO SOUTHERN QUEBEC SUNDAY NIGHT WHILE DRAGGING A STRONG COLD FRONT
DOWN THE LENGTH OF THE LAKE. AHEAD OF THE FRONT THIS EVENING...A
MODERATE SOUTHWESTERLY GRADIENT WILL KEEP WINDS ARND 15-25KT.
FOLLOWING THE FRONTAL PASSAGE...VERY COLD AIR WILL FILTER IN OVER
THE LAKE OVERNIGHT TONIGHT AS STRONG HIGH PRESSURE BUILDS ACROSS
THE CENTRAL PLAINS. THE COMBINATION OF THE VERY STRONG COLD
ADVECTION AND STRONG PRESSURE GRADIENT WILL LEAD TO NORTHWEST TO
NORTH GALES DEVELOPING...INITIALLY OVER THE NORTHERN PORTIONS OF
THE LAKE DURING THE EARLY MORNING HOURS. GALES WILL QUICKLY SPREAD
DOWN THE REMAINDER OF THE LAKE EARLY SUNDAY MORNING. THE VERY COLD
AIR...STRONG WINDS AND HIGH WAVES WILL LEAD TO THE POTENTIAL FOR
MODERATE TO HEAVY FREEZING SPRAY...WITH THE GREATEST CHANCE FOR
HEAVY FREEZING SPRAY TO OCCUR DURING THE PERIOD OF THE GALE
WARNING...THOUGH SOME HEAVY SPRAY POTENTIAL COULD STILL LINGER AS
WINDS DROP BELOW GALE FORCE DUE TO THE SLOW DECLINE IN WIND
HEIGHTS AND THE ADVECTION OF COLDER AIR WELL BEHIND THE FRONTAL
BOUNDARY. FOR THE NEARSHORE WATERS...THE BETTER CHANGE FOR GALES
WILL BE OVER THE INDIANA WATERS DUE TO THE DIRECT NORTH TO
NORTHWEST FETCH PREDOMINANTLY OVER ALL WATER...WHILE THE ILLINOIS
NEARSHORE WATERS SHOULD REMAIN BELOW GALE FORCE DUE TO SLIGHTLY
WEAKER FLOW OFF LAND. WINDS AND WAVES WILL DIMINISH AS THE HIGH
SPREADS EAST MONDAY NIGHT AND TUESDAY...BUT ANOTHER LOW IS
EXPECTED TO DEVELOP OVER THE NORTHERN PLAINS MONDAY MORNING AND
TRACK EAST ACROSS NORTHERN ILLINOIS MONDAY NIGHT AND THEN CONTINUE
TO THE EASTERN GREAT LAKES TUESDAY MORNING. AS YET ANOTHER ARCTIC
HIGH PRESSURE SYSTEM BUILDS INTO THE NORTHERN PLAINS TUESDAY
NIGHT...STRONG NORTHWEST WINDS WILL DEVELOP AGAIN FOR TUESDAY AND
TUESDAY NIGHT...BUT THIS SYSTEM SHOULD BE ACCOMPANIED BY A WEAKER
PRESSURE GRADIENT AND THE AIRMASS WILL NOT BE QUITE AS COLD...SO
ANOTHER ROUND GALES AND FREEZING SPRAY IS NOT ANTICIPATED AT THIS
TIME.
KREIN
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...SMALL CRAFT ADVISORY...NEARSHORE GARY TO MICHIGAN CITY IN UNTIL 9 AM SUNDAY.
HEAVY FREEZING SPRAY WARNING...LMZ080-LMZ567-LMZ669-LMZ671-
LMZ673-LMZ675-LMZ740-LMZ741-LMZ742-LMZ743-LMZ744-LMZ745-
LMZ777-LMZ779-LMZ868-LMZ870-LMZ872-LMZ874-LMZ876-LMZ878...9
AM SUNDAY TO MIDNIGHT MONDAY.
GALE WARNING...LMZ080-LMZ567-LMZ669-LMZ671-LMZ673-LMZ675-LMZ744-
LMZ745-LMZ777-LMZ779-LMZ868-LMZ870-LMZ872-LMZ874-LMZ876-
LMZ878...9 AM SUNDAY TO 9 PM SUNDAY.
HEAVY FREEZING SPRAY WARNING...LMZ261-LMZ362-LMZ364-LMZ366-
LMZ563-LMZ565...4 AM SUNDAY TO MIDNIGHT MONDAY.
GALE WARNING...LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-LMZ565...4 AM
SUNDAY TO 6 PM SUNDAY.
SMALL CRAFT ADVISORY...NEARSHORE WINTHROP HARBOR TO GARY IN UNTIL 4 AM
MONDAY.
&&
$$
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FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
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WWW.YOUTUBE.COM/NWSCHICAGO
Area Forecast Discussion
National Weather Service Lincoln IL
1149 PM CST Sat Dec 28 2013
.DISCUSSION...
ISSUED 859 PM CST Sat Dec 28 2013
Made a few minor adjustments to the afternoon forecast package.
The first was to bump up cloud cover for the rest of the night.
The southern stream wave heading toward the Ohio Valley from the
southern Plains has been spilling more cloud cover back toward the
area than previously expected per recent satellite loops. See no
reason why this trend will not continue through the night. Also,
increased the speed of the approaching arctic front just a bit per
recent observational trends and short range rapid update model
progs. Otherwise, only a few tweaks were needed to the hourly
trends.
Bak
&&
.AVIATION...
ISSUED 1149 PM CST Sat Dec 28 2013
A strong cold front is continuing to approach the central Illinois
terminals from the northwest. Until the front gets here, high
level VFR cigs and southwest winds around 10 kts are likely. The
front should move across the area between 11Z and 14Z. Winds are
expected to swing to the northwest and gust to at least 20 kts
behind the front, and low end MVFR cigs will spread across the
area. Added a 2 hour tempo for IFR cigs behind the front at KPIA
and KBMI based on upstream observations and HRRR cloud progs. Little/no
precipitation is anticipated with fropa. Winds will slowly die off
Sunday night. Skies may also begin to scatter our, but have left
MVFR cigs in place for now as the clearing appears too rapid.
Bak
&&
.PREV DISCUSSION...
ISSUED 215 PM CST Sat Dec 28 2013
Another unseasonably warm afternoon across central through southeast
Illinois thanks to abundant sunshine and a gusty southwest wind.
Early afternoon temperatures have already climbed into the lower
40s northwest to the lower 50s west and south. An Arctic cold
front was located over far southeast South Dakota through central
Nebraska with strong 3 hourly pressure rises noted behind the
boundary. Temps just ahead of the front were in the mid 40s to mid
50s while only in the single digits behind the front in extreme
northern South Dakota.
SHORT TERM...Tonight through Tuesday
Bone chilling cold headed towards our area late Sunday and Monday
with wind chill readings dropping to around 20 below zero across
the north by Monday morning.
Temps/Wind chills the main forecast concerns this period along
with light snow chances as fast moving shortwaves ride southeast
along the Arctic air mass about every other day.
No major differences seen in the models through Monday, at least
with the handling of the strong cold front late tonight into
Sunday morning. The Arctic boundary is forecast to streak southeast
tonight and push across our area Sunday morning. Southwest winds
ahead of the front will keep temperatures relatively mild tonight,
at least in comparison to what we will be seeing early in the
week. On Sunday, most areas should see morning high temperatures
with falling temps expected in the afternoon.
As far as precip is concerned on Sunday, the southern stream system,
currently pushing across Texas and spreading clouds as far north
as our southeast counties, may bring a period of light rain and snow
to the southeast tomorrow morning into the afternoon hours before
the temp profile supports more light snow. Meanwhile, further north,
as the Arctic air mass settles southeast into our area and a 500
mb shortwave approaches from the northwest in the afternoon, there
may be enough moisture in place to support scattered snow showers
from time to time. The NAM-WRF Bufkit sounding profiles suggest
the threat for a brief period of light drizzle or possibly freezing
drizzle before the depth of the cold air increases enough Sunday
morning to support mainly flurries. For now, will not mention in
the forecast as the window of opportunity for any drizzle/freezing
drizzle looks too brief to include in the forecast. Precip amounts
look very light and will continue with the 20 to 30 POPs.
Any lingering snow showers or flurries should be to our east by
tomorrow evening as the Arctic air mass becomes firmly entrenched
across the forecast area overnight. Forecast soundings for Sunday
night into Monday continues to indicate winds to hold up most of
the night as the very cold air mass settles in, creating dangerously
cold wind chills, generally ranging from -10 to -20 northwest, and
from 0 to -10 over the remainder of the area Monday morning. Wind
chills will only gradually improve during the day on Monday as
winds slowly decrease as the center of the cold air mass tracks
over our area by evening. Clouds will be on the increase during
the day, especially across the north as a fast moving shortwave
approaches the lower Great Lakes from the northwest by evening.
It still appears the better forcing and moisture will remain to
our north Monday night into early Tuesday but will continue to
hold on to low chance POPs over our northern counties before the
system pushes off to our east Tuesday. A stronger shortwave will
follow the Monday night system for later Tuesday and Tuesday night
spreading the threat for light snow further south. Both the GFS
and latest ECMWF showing better deep layered forcing and moisture
associated with this feature, so POPs will be increased further
south late Tuesday into Tuesday night. With the snow ratio`s on
the order of 20:1, parts of our northern counties may see some light
accumulations Tuesday night.
LONG TERM...Wednesday through Saturday
Little change expected in the longwave pattern through most of this
forecast period as the cold vortex anchored north of the Great Lakes
will continue to bring us below normal temps thru this period. Some
of the ensemble members suggest at least a temporary break in the
very cold pattern late in the period as the Canadian vortex shifts
off to the east, while another upper low rotates south over central
Canada, probably to set up shop near Hudson Bay again beyond this
forecast period.
Another fast moving shortwave embedded in the northwest flow will
track southeast across the Plains on Wednesday inducing a surface
wave across the southern Plains, which models were suggesting would
move northeast across southern Illinois into Indiana on Thursday,
followed by another shot of Arctic air for the end of the week.
Before the Arctic air moves in, both the latest ECMWF and GEM
global indicates some fairly significant lift associated ahead of
the H5 trof later Wednesday into early Thursday as the upper wave
digs into the longwave trof position, which may bring another
threat for snow to the area. The 00z Canadian had depicted this
scenario first on its 00z run last evening, now the 12z ECMWF is
latching on to the snowier look to the Wed night into Thursday.
Both models indicate a closed 850 mb low across central Illinois
late Wednesday night or Thursday which would enhance snowfall over
the area. Latest SREF not as aggressive with the system while the
12z GFS indicates the better lift will track mostly south of area.
So until we get some continuity with models for the mid-week system,
will keep the POPs in the chance category for now.
As mentioned above, models are trending towards a warmer pattern,
at least a temporary one, at the end of this forecast period as the
polar vortex migrates off into eastern Canada. Meanwhile, our
upper flow begins to back in response to a trof pushing into the
Rockies late next weekend, resulting in warmer temperatures for
Saturday with highs in the 30s.
Smith
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS GOODLAND KS
1010 PM MST SAT DEC 28 2013
.SHORT TERM...(THIS EVENING THROUGH SUNDAY)
ISSUED AT 117 PM MST SAT DEC 28 2013
THE LAST WEEKEND OF 2013 KICKED OFF YESTERDAY WITH WELL ABOVE-NORMAL
TEMPERATURES AND WILL END WITH A VERY COLD SUNDAY. AN ARCTIC COLD
FRONT ON THE WAY TODAY WILL BRING THE COLD AIR AS WELL AS STRONG
WINDS. A FEW FLURRIES ARE POSSIBLE TONIGHT INTO EARLY SUNDAY...BUT
THE MAIN IMPACT OF THIS FRONT WILL BE THE WIND AND COLD. ON SUNDAY
SKIES WILL BECOME MOSTLY SUNNY BUT TEMPERATURES WILL HAVE A TOUGH
TIME GETTING ABOVE FREEZING.
TODAY...SATURDAY...SUNNY AND MILD TO START...BECOMING WINDY AND
COLD. FRONTAL PASSAGE LOOKS TO OCCUR IN THE EARLY AFTERNOON...WITH A
REINFORCING SHOT OF COLD AIR TONIGHT. AHEAD OF THE FRONT IT WILL BE
A NICE DAY SIMILAR TO YESTERDAY WITH SUNNY SKIES...MILD TEMPS...AND
A LIGHT WEST/SOUTHWESTERLY WIND. HIGHS MIGHT EVEN APPROACH RECORD
VALUES TODAY WHICH ARE IN THE MID TO UPPER 60S FOR MOST STATIONS. /RECORD
HIGH OF 67 AT HILL CITY LOOKS TO HAVE THE BEST CHANCE OF BEING
BROKEN OUT OF THE FOUR ASOS SITES./ THE INITIAL FRONT WILL RACE
SOUTH ACROSS THE REGION EARLY THIS AFTERNOON...BRINGING GUSTY WINDS.
DECIDED TO REMOVE THE BLOWING DUST FROM THE WX GRID AS EXPECT ANY
BLOWING DUST/DIRT TO BE VERY LIMITED SPATIALLY/TEMPORALLY BASED ON
THE LATEST SHORT-TERM GUIDANCE. MID/HIGH LEVEL CLOUD COVER
ASSOCIATED WITH THE FRONT WILL ARRIVE LATER THIS AFTERNOON...WITH
LOW-LEVEL STRATUS CLOUDS THIS EVENING.
TONIGHT...STRONG PRESSURE RISES SUPPORT WINDY CONDITIONS THROUGH THE
NIGHT WITH LIGHT SNOW POSSIBLE IN EASTERN COLORADO. OVERCAST SKIES
WITH A LOW STRATUS DECK IN THE EVENING AND MID-LEVEL CLOUDS
PERSISTING THROUGH MOST OF THE NIGHT. WINDS WILL CONTINUE AS STRONG
PRESSURE RISES /5-8 MB/HR/ ARE EXPECTED AND MIXING OCCURS. A FEW
FLURRIES/LIGHT SNOW POSSIBLE IN EASTERN COLORADO AND PORTIONS OF NW
KANSAS WITH THE COMBINATION OF LOW LEVEL MOISTURE AND
FRONTOGENETICAL FORCING IN PLACE. GUIDANCE HAS BEEN QUITE CONSISTENT
RUN-TO-RUN...AND EARLY NCEP RAP AND ESRL RAP RUNS SUPPORT AT LEAST
SOME FLURRIES FOR MOST SPOTS. ACCUMULATIONS ARE NOT EXPECTED TO
AMOUNT TO MUCH...BUT WOULD NOT BE SURPRISED IF WESTERN PARTS OF
CHEYENNE/KIT CARSON COUNTIES IN COLORADO RECEIVE A HALF INCH.
/THOUGH IT WILL BE HARD TO MEASURE WITH ALL THE WIND.../ LOWS WILL
REACH THE SINGLE DIGITS IN MANY LOCATIONS WITH 850MB TEMPS IN THE
-12 TO -15 C RANGE AND STRONG COLD AIR ADVECTION.
TOMORROW...SUNDAY...COLD AND MOSTLY SUNNY. AT DAWN SUNDAY CLOUDS
WILL BE CLEARING FROM NORTHWEST TO SOUTHEAST...BECOMING MOSTLY SUNNY
EVERYWHERE BY THE AFTERNOON. WINDS WILL BE LIGHT OUT OF THE
NORTH/NORTHWEST AT 10 TO 15 MPH. DESPITE THE SUN HIGHS WILL STRUGGLE
TO REACH ABOVE FREEZING AS HIGH PRESSURE STRENGTHENS ACROSS THE
NORTHERN PLAINS.
.LONG TERM...(SUNDAY NIGHT THROUGH SATURDAY)
ISSUED AT 200 PM MST SAT DEC 28 2013
SUNDAY NIGHT-TUESDAY...PERIODIC INCREASES IN MID AND HIGH CLOUDS
EXPECTED UNDER NORTHWEST FLOW ALOFT. NO PRECIPITATION EXPECTED. MAY
SEE SOME BREEZY NORTHWEST WINDS MONDAY AFTERNOON.
LOWS SUNDAY NIGHT AROUND 10 ACROSS THE EAST AND WESTERN PORTIONS OF
CHEYENNE COUNTY COLORADO...LOW TO MID TEENS ELSEWHERE. HIGHS MONDAY
MID 40S TO AROUND 50. MAY HAVE A BIT OF SNOW COVER TO DEAL WITH
ACROSS THE WEST AND HAVE MID 40S IN THAT AREA. ON TUESDAY 850
TEMPERATURES WARM ABOUT 13-15F ACROSS THE AREA SUPPORTING HIGHS IN
THE MID 50S (NORTHEAST) TO MID 60S (WEST). BIAS CORRECTED GRIDS
ALONG THE 2M/MET/MAV ARE SEVERAL DEGREES COOLER. HAVE GENERALLY
BLENDED ALL SOLUTIONS TRYING TO TREND A BIT CLOSER TO 850
TEMPERATURES. HAVE SETTLED ON LOW TO MID 50S FAR NORTHEAST-EAST WITH
UPREAR 50S TO AROUND 60 ACROSS THE WESTERN/SOUTHWESTERN 2/3 OF THE
AREA.
TUESDAY NIGHT-SATURDAY...THERE IS A SLIGHT CHANCE OF LIGHT
PRECIPITATION WEDNESDAY AS A LARGE AREA OF MOISTURE MOVES IN FROM
THE NORTHWEST...AIDED BY APPROACHING LEFT FRONT PORTION OF UPPER
JET. BETTER CHANCES OF PRECIP GENERALLY ACROSS NORTHEAST 1/2 OF THE
FORECAST AREA. THIS SYSTEM EXITS THE AREA EARLY WEDNESDAY NIGHT.
OTHERWISE...A DRY FORECAST EXPECTED. LOWS THROUGH THURSDAY NIGHT IN
THE TEENS TO LOW 20S WITH MID 20S FRIDAY NIGHT. HIGHS WEDNESDAY IN
THE LOW 30S EAST TO LOW/MID 40S FAR WEST...SLOWLY WARMING INTO THE
LOW TO MID 40S (EAST TO WEST) THURSDAY. ON FRIDAY WE SHOULD RETURN
TO ABOVE NORMAL TEMPERATURES WITH UPPER 40S TO MID 50S. A RETURN TO
NEAR NORMAL HIGHS SATURDAY WITH LOW TO MID 40S.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT)
ISSUED AT 1005 PM MST SAT DEC 28 2013
AT KGLD...CEILINGS HAVE BEEN BOUNCING BETWEEN VFR AND MVFR ALL
EVENING BUT SHOULD SETTLE MORE IN THE MVFR CATEGORY DURING THE
OVERNIGHT HOURS. THERE WILL BE A CHANCE FOR LIGHT SNOW AS WELL
WHICH COULD BRIEFLY REDUCE VISIBILITY TO AROUND 5SM. FLIGHT
CATEGORIES WILL QUICKLY IMPROVE AROUND SUNRISE AS UPPER SYSTEM
MOVES OUT. SURFACE WINDS WILL BE BREEZY TO WINDY THROUGH THE
OVERNIGHT...DIMINISHING SUNDAY MORNING.
AT KMCK...VFR WILL BE THE PRIMARY FLIGHT CATEGORY ALTHOUGH CANT
RULE OUT A BRIEF CEILING REDUCTION OVERNIGHT TO MVFR. NO
PRECIPITATION IS EXPECTED. SURFACE WINDS WILL BE BREEZY TO WINDY
THROUGH THE OVERNIGHT...DIMINISHING SUNDAY MORNING.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
CO...NONE.
NE...NONE.
&&
$$
SHORT TERM...JJM
LONG TERM...99
AVIATION...024
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
459 AM EST SUN DEC 29 2013
.SHORT TERM...(THIS EVENING THROUGH SUNDAY)
ISSUED AT 419 PM EST SAT DEC 28 2013
A STALLED FRONTAL BOUNDARY OVER SOUTHERN LAKE SUPERIOR AND NORTHERN
UPPER MICHIGAN HAS LED TO DREARY CONDITIONS FOR MUCH OF UPPER
MICHIGAN TODAY. ON THE PLUS SIDE...TEMPERATURES HAVE BEEN IN THE
LOW TO MID 30S ALONG AND SOUTH OF THE BOUNDARY WHERE THERE HAVE
EVEN BEEN A FEW PEAKS OF SUNSHINE. JUST TO THE NORTH OF THE
BOUNDARY...FAVORABLE EASTERLY FLOW OFF LAKE SUPERIOR HAS LED TO
SOME FZDZ...FOG...AND -SHSN OVER THE KEWEENAW PENINSULA. A SPOTTER
REPORT AROUND 3PM INDICATED A SLIGHT GLAZE IN MOHAWK SHORTLY
AFTER THE VISIBILITY REALLY DROPPED AT KCMX. THINK THAT
FREEZING DRIZZLE WILL REMAIN A THREAT OVER THE NEXT COUPLE OF HOURS
AND EVEN DRIFT SOUTHEAST THROUGH THE EVENING...AS MODELS SHOW A
LACK OF ICE CRYSTALS IN THE CLOUDS BEFORE THE MAIN PRECIPITATION
ARRIVES FROM SOUTHERN CANADA LATE THIS EVENING. ALSO FOR THIS
EVENING...DID ADD SOME PATCHY FOG OVER THE SOUTHEAST PART OF THE
CWA WHERE WINDS WILL BE LIGHT AND THERE HAVE BEEN SOME BREAKS IN
THE CLOUDS.
THE LOW THAT IS CURRENTLY CENTERED IN SOUTH CENTRAL MINNESOTA WILL
CONTINUE EAST TONIGHT AND SUNDAY...BEING CENTERED JUST NORTH OF LAKE
ONTARIO BY 00Z MONDAY. AS THIS LOW SWEEPS EAST...AN AREA OF SNOW
(CURRENTLY IN SOUTHWEST ONTARIO AND ALSO ENTERING NORTHWEST
MINNESOTA) WILL SWEEP ACROSS THE UPPER GREAT LAKES LATE THIS
EVENING THROUGH EARLY SUNDAY MORNING. THE SYNOPTIC SNOW WILL BE
AIDED BY THE RIGHT REAR OF THE 110KT UPPER JET THAT SWEEPS ACROSS
TONIGHT. IN ADDITION...POCKET OF 800-600MB FGEN WILL SLIDE THROUGH
WITH THE 850/700MB TROUGH. THUS...EXPECT A PERIOD OF LIGHT SNOW TO
MOVE ACROSS MUCH OF UPPER MICHIGAN FROM WEST TO EAST. WITH THE BEST
FORCING OVER THE NORTHERN HALF OF THE CWA...EXPECT THE BEST SYNOPTIC
SNOWFALL THERE...WHICH WILL BE AIDED BY LAKE ENHANCEMENT. OVER THE
SOUTHERN HALF...ONLY EXPECT A LIGHT DUSTING TO AN INCH AWAY FROM THE
LAKE SUPERIOR INFLUENCES WITH SNOW RATIOS AROUND NORMAL VALUES OF
13-1.
AS FOR THE LAKE ENHANCEMENT...COLD AIR SURGING IN BEHIND THE LOW
(FALLING FROM RAP ANALYZED VALUES OF 0C FROM WEST-EAST OVER THE
CENTRAL U.P. AT 20Z TO -10 TO -16C AT 12Z SUNDAY AND -23C BY 00Z
MONDAY) WILL LEAD TO LAKE ENHANCEMENT FOR AREAS NEAR LAKE SUPERIOR
AS THE WIND DIRECTIONS BECOME FAVORABLE. THE WINDS WILL BE OUT OF
THE NORTHEAST INITIALLY THIS EVENING OVER WESTERN LAKE
SUPERIOR...BUT AS THE SURFACE/925MB LOW MOVES EAST-NORTHEAST THROUGH
NORTHEAST WISCONSIN AND SOUTH CENTRAL UPPER MICHIGAN TONIGHT...THE
WINDS WILL TRANSITION TO THE NORTH OVERNIGHT...NNW SUNDAY
MORNING...AND THEN NW SUNDAY AFTERNOON. THUS...EXPECT THE INITIAL
ENHANCEMENT TO OCCUR LATE IN THE EVENING OVER THE NE FAVORED
LOCATIONS AND THEN TRANSITION WITH THE WINDS INTO SUNDAY MORNING.
THESE STEADY BACKING WINDS WILL LIKELY BE ONE OF THE LIMITING
FACTORS TO HEAVIER SNOWFALL AMOUNTS. THE SECOND ITEM THAT SHOULD
KEEP SNOWFALL AMOUNTS IN THE LES ADVISORY CATEGORY WILL BE THE SHORT
PERIOD WHEN THE LAKE ENHANCEMENT AND LOW LEVEL TEMPERATURE PROFILE
FALL WITHIN THE DGZ. AT MOST LOCATIONS...IT APPEARS LIKE IT WILL
ONLY OCCUR FOR A 3 TO MAYBE 6HOUR PERIOD. THUS...EVEN THOUGH SNOW
RATIOS WILL QUICKLY RISE TO THE LOWER 20S...THEY WILL QUICKLY FALL
ONCE THE DEEPER MOISTURE DEPARTS AND THE INCREASING COLD AIR MOVES
THE CLOUD OUT OF THE DGZ. FINALLY...GUSTY WINDS MAY LIMIT SNOW
RATIOS FROM GROWING MUCH ABOVE 22/23-1 DURING THE FAVORED
PERIOD...EVEN THOUGH ALL OF THE CLOUD IS WITHIN THE DGZ.
OVERALL...ONLY MADE MINOR TWEAKS TO MUCH OF THE SNOWFALL FORECAST
FOR TONIGHT INTO SUNDAY MORNING...LARGELY WITH HANDLING THE TIMING
OF THE CHANGE OVER TO SNOW FROM NORTHWEST TO SOUTHEAST. THE FAVORED
HIGHER TERRAIN LOCATIONS WILL LIKELY SEE AMOUNTS THROUGH SUNDAY
MORNING IN THE 3-8INCH RANGE...WITH THE GREATEST AMOUNTS OVER THE
HURON MOUNTAINS WITH THE LONGER PERIOD OF FAVORABLE WIND
DIRECTIONS. THAT WOULD BE THE ONLY LOCATIONS WHERE SOME CONCERN OF
NEAR WARNING AMOUNT SNOW WOULD OCCUR...BUT THE SOCIETAL IMPACT WILL
BE LIMITED.
DEEPER MOISTURE FROM THE LOW PULLS OUT QUICKLY FROM WEST TO EAST ON
SUNDAY MORNING AND LEADS TO A TRANSITION TO PURE LAKE EFFECT. WITH
THAT DEEPER MOISTURE DEPARTING...MODELS ARE ONLY SHOWING MOISTURE
AND INVERSION HEIGHTS AROUND 4KFT...BUT WITH LAKE INDUCED
EQUILIBRIUM LEVELS AROUND 5-6KFT...COULD STILL BE SOME STRONGER SNOW
SHOWERS. BUT WITH COLDER AIR CONTINUING TO SURGE IN...MUCH OF THE
CLOUD LAYER WILL MOVE TO THE TOP OF OR ABOVE THE DGZ...WHICH SHOULD
LEAD TO A TRANSITION TO MORE OF COLUMN/PLATES. THEREFORE...WILL
CONTINUE THE IDEA OF LOWERING SNOW RATIOS TO THE HIGH TEENS OR
AROUND 20-1 FROM WEST TO EAST THROUGH THE DAY SUNDAY. THIS SHOULD
LEAD TO LESSER SNOWFALL AMOUNTS IN THE AFTERNOON...WHICH WILL STILL
BE AIDED BY SLOWLY BACKING WINDS TO THE NORTHWEST. OVERALL...HAVE
AFTERNOON AMOUNTS OF 1-2 INCHES IN MOST LOCATIONS...WITH SLIGHTLY
HIGHER VALUES OVER WESTERN ALGER COUNTY. THEREFORE...WILL KEEP LES
ADVISORIES AS IS...ALTHOUGH THE LONG TERM DID MAKE SOME ADJUSTMENTS
TO ALGER TO EXTEND INTO MONDAY. THINK THAT COVERS THE OVERALL IDEA
VERY WELL...SINCE THE NEGATIVES WITH SNOW RATIOS AND BACKING WINDS
SHOULD LIMIT THE POTENTIAL FOR 12HR SNOW AMOUNTS REACHING WARNING
VALUES.
THE COLD AIR SURGING IN WILL LEAD TO FALLING TEMPERATURES STARTING
LATE THIS EVENING OVER THE WEST AND PUSHING ACROSS THE REST OF THE
AREA THROUGH THE NIGHT. OVERNIGHT LOWS FOR TONIGHT AND HIGHS FOR
TOMORROW ARE FAIRLY TRICKY...AS THEY BOTH WILL LIKELY OCCUR DURING
THE TWO HOUR OVERLAP BETWEEN 12-14Z. THUS...TRIED TO FOCUS ON TEMPS
DURING THAT PERIOD TO USE FOR SIMILAR VALUES. WITH THE COLD AIR
CONTINUING TO SURGE IN THROUGH THE DAY ON SUNDAY...EXPECT STEADY OR
SLOWLY FALLING TEMPERATURES THROUGH THE REST OF THE DAY ON
SUNDAY. AFTERNOON VALUES OVER THE WEST WILL BE IN THE LOWER SINGLE
DIGITS ABOVE ZERO AND AROUND 10 DEGREES OVER THE EAST HALF.
FACTORING IN WIND CHILLS...TOMORROW AFTERNOON WILL FEEL ABOUT 50
DEGREES COLDER THAN THIS PAST AFTERNOON.
.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 455 AM EST SUN DEC 29 2013
MON INTO TUE...AS THE POLAR VORTEX SLOWLY SHIFTS SE FROM HUDSON
BAY...THE MODELS SUGGEST A SHORTWAVE TROUGH WILL MOVE THROUGH THE
UPPER MS VALLY TOWARD THE WRN GREAT LAKES. THE BEST ISENTROPIC LIFT
NEAR THE 850 MB FRONT AND POTENTIAL FOR WIDESPREAD LIGHT SNOW IS
EXPECTED TO REMAIN TO THE SOUTH OF UPPER MI. AS THE LOW LEVEL WINDS
BACK AHEAD OF THE SHRTWV...THE LES OVER THE NE CWA WILL GRADUALLY
LIFT TO THE NORTH AND POSSIBLY MOVE OFFSHORE BY LATE IN THE DAY.
ADDITIONAL SNOWFALL AMOUNTS IN THE MORNING MAY AMOUNT TO 1 TO 3
INCHES OVER FAR ERN ALGER COUNTY AND NRN LUCE COUNTY. OVER THE
WEST...CONVERGENT WRLY FLOW WILL LIKELY BRING AN INCREASE IN LES
INTENSITY OVER THE KEWEENAW. ALTHOUGH ADVY SNOWFALL AMOUNTS IN THE 2
TO 6 INCH RANGE MAY BE POSSIBLE...CONFIDENCE IN THE LOW LEVEL WIND
DETAILS IS LIMITED. VEERING WINDS IN THE WAKE OF THE SHRTWV WILL
PUSH THE LES BACK INTO AREAS FAVORED BY NW FLOW. LAKE INDUCED
TROUGHING IS EXPECTED TO FOCUS THE STRONGEST LOW LEVEL CONV BACK INTO
THE NE PORTION OF THE CWA FROM P53 EASTWARD. NAM FCST SOUNDINGS
ALSO SUGGEST THAT THE DGZ WILL BE MORE FAVORABLY PLACED IN THE
CONVECTIVE LAYER TO BOOST SLR VALUES AND OVERALL SNOWFALL
POTENTIAL.
WIND CHILL VALUES INTO THE ADVISORY RANGE FROM -25 TO -35 EARLY
MONDAY OVER THE INTERIOR WEST WILL MODERATE BY MID MORNING WITH DIURNAL
WARMING AND DIMINISHING WINDS. EVEN THOUGH TEMPS MAY NOT BE AS COLD
EARLY TUE...SLIGHTLY STRONGER WINDS WILL AGAIN PUSH WIND CHILLS INTO
THE -25 TO -35 ADVY RANGE OVER THE WEST.
WED INTO THU...THE NEXT SIGNIFICANT SHORTWAVE TROUGH IS EXPECTED TO
REMAIN WELL TO THE SOUTH BRINGING SNOW TO MAINLY IA/NRN IL/SRN WI
AND THE SOUTHERN GREAT LAKES. GREAT LAKES AGGREGATE TROUGHING WILL
INFLUENCE GENERALLY LIGHT LOW LEVEL WIND FIELDS AND THE RESULTING LES
INTO UPPER MI AS 850 MB TEMPS REMAIN IN THE -22C TO -26C RANGE. ALTHOUGH
THE MAIN FOCUS FOR HIGHER LES ACCUMULATIONS WILL REMAIN OVER THE ERN
CWA...AT LEAST LIGHT LES WILL PERSIST OVER THE WEST THROUGH THE
PERIOD.
FRI-SAT...MODELS WERE IN GENERAL AGREEMENT WITH TREND TOWARD A LESS
AMPLIFIED PATTERN. AS SFC HIGH PRESSURE SLIDES EAST LATE IN THE
WEEK...THE ECMWF AND GFS DEVELOP AREA OF LIGHT SNOW IN REGION OF
WAA/ISENTROPIC ASCENT AHEAD OF A SHRTWV MOVING INTO NW ONTARIO. THIS
SNOW LOOKS TO SPREAD INTO UPPER MI LATE FRI OR FRI NIGHT. AS SYSTEM
SNOW TAPERS OFF EARLY SAT...LES COULD DEVELOP LATE IN THE DAY AS
WINDS SHIFT TO THE NW BEHIND FRONTAL PASSAGE.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT)
ISSUED AT 1226 AM EST SUN DEC 29 2013
PERIODS OF -SN/-SHSN/BLSN WITH IFR CONDITIONS IN THE GUSTY N FLOW IN
THE WAKE OF LO PRES SHIFTING TO THE E THRU THE CENTRAL GRT LKS WL
GIVE WAY TO MVFR CONDITIONS ON SUN AS STRONG SUBSIDENCE/DIMINISHING
WINDS WEAKEN THE SN/GUSTY WINDS/BLSN. THE MOST RAPID IMPROVEMENT WL
OCCUR AT CMX...WHERE THE EXPECTED N WIND DOES NOT PRESENT AS SGNFT
AN UPSLOPE WIND COMPONENT. BUT AS THE FLOW CONTINUES TO BACK TO THE
NW ON SUN AFTN/EVNG...IFR VSBYS WL REDVLP THERE WITH A MORE FVRBL
WIND. AT THE SAME TIME...THE DOWNSLOPE NATURE OF THE FLOW INTO SAW
WL CAUSE VFR CONDITIONS BY LATER IN THE DAY ON SUN.
&&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 419 PM EST SAT DEC 28 2013
WINDS TO STAY LIGHT UNTIL SFC LOW BRINGS TIGHTENING PRESSURE
GRADIENT TO WESTERN LAKE SUPERIOR THIS AFTERNOON. BY LATE
AFTERNOON...WILL SEE FREQUENT GALE FORCE GUSTS OVER WESTERN LAKE
SUPERIOR WITH NE GALES EXPECTED BY THE EVENING. AS THE SFC LOW
PASSES TO THE SE OF THE AREA OVERNIGHT...NORTH WINDS TO GRADUALLY
RELAX. MUCH COLDER AIR ARRIVING TONIGHT WILL PRODUCE HEAVY FREEZING
SPRAY AS WELL. WINDS GO BELOW 25 KNOTS SUNDAY AFTERNOON AND BELOW 20
KNOTS BY MONDAY AFTERNOON. WINDS REMAIN BELOW 20 KNOTS THROUGH THE
REMAINDER OF THE FORECAST.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
LAKE EFFECT SNOW ADVISORY UNTIL 7 PM EST /6 PM CST/ THIS EVENING
FOR MIZ001>005-009-084.
WIND CHILL ADVISORY FROM MIDNIGHT EST /11 PM CST/ TONIGHT TO 10
AM EST /9 AM CST/ MONDAY FOR MIZ011-084.
LAKE EFFECT SNOW ADVISORY FROM 1 PM THIS AFTERNOON TO 7 AM EST
MONDAY FOR MIZ085.
WIND CHILL ADVISORY FROM 7 PM EST /6 PM CST/ THIS EVENING TO 10
AM EST /9 AM CST/ MONDAY FOR MIZ002-009-010.
LAKE EFFECT SNOW ADVISORY UNTIL 1 PM EST MONDAY FOR MIZ006.
LAKE EFFECT SNOW ADVISORY FROM 7 PM THIS EVENING TO 1 PM EST
MONDAY FOR MIZ007.
WIND CHILL ADVISORY FROM 4 AM TO 10 AM EST MONDAY FOR MIZ004-005.
LAKE SUPERIOR...
HEAVY FREEZING SPRAY WARNING UNTIL 1 AM EST WEDNESDAY FOR LSZ267.
HEAVY FREEZING SPRAY WARNING UNTIL 7 AM EST WEDNESDAY FOR LSZ265-
266.
GALE WARNING UNTIL 7 AM EST THIS MORNING FOR LSZ263>266.
HEAVY FREEZING SPRAY WARNING UNTIL 7 AM EST MONDAY FOR LSZ248-
249-264.
HEAVY FREEZING SPRAY WARNING UNTIL 1 AM EST MONDAY FOR LSZ263.
HEAVY FREEZING SPRAY WARNING UNTIL 7 PM EST /6 PM CST/ THIS
EVENING FOR LSZ162-240>247.
HEAVY FREEZING SPRAY WARNING UNTIL 6 PM EST MONDAY FOR LSZ250-
251.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...SRF
LONG TERM...JLB
AVIATION...KC
MARINE...SRF
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
1226 AM EST SUN DEC 29 2013
.SHORT TERM...(THIS EVENING THROUGH SUNDAY)
ISSUED AT 419 PM EST SAT DEC 28 2013
A STALLED FRONTAL BOUNDARY OVER SOUTHERN LAKE SUPERIOR AND NORTHERN
UPPER MICHIGAN HAS LED TO DREARY CONDITIONS FOR MUCH OF UPPER
MICHIGAN TODAY. ON THE PLUS SIDE...TEMPERATURES HAVE BEEN IN THE
LOW TO MID 30S ALONG AND SOUTH OF THE BOUNDARY WHERE THERE HAVE
EVEN BEEN A FEW PEAKS OF SUNSHINE. JUST TO THE NORTH OF THE
BOUNDARY...FAVORABLE EASTERLY FLOW OFF LAKE SUPERIOR HAS LED TO
SOME FZDZ...FOG...AND -SHSN OVER THE KEWEENAW PENINSULA. A SPOTTER
REPORT AROUND 3PM INDICATED A SLIGHT GLAZE IN MOHAWK SHORTLY
AFTER THE VISIBILITY REALLY DROPPED AT KCMX. THINK THAT
FREEZING DRIZZLE WILL REMAIN A THREAT OVER THE NEXT COUPLE OF HOURS
AND EVEN DRIFT SOUTHEAST THROUGH THE EVENING...AS MODELS SHOW A
LACK OF ICE CRYSTALS IN THE CLOUDS BEFORE THE MAIN PRECIPITATION
ARRIVES FROM SOUTHERN CANADA LATE THIS EVENING. ALSO FOR THIS
EVENING...DID ADD SOME PATCHY FOG OVER THE SOUTHEAST PART OF THE
CWA WHERE WINDS WILL BE LIGHT AND THERE HAVE BEEN SOME BREAKS IN
THE CLOUDS.
THE LOW THAT IS CURRENTLY CENTERED IN SOUTH CENTRAL MINNESOTA WILL
CONTINUE EAST TONIGHT AND SUNDAY...BEING CENTERED JUST NORTH OF LAKE
ONTARIO BY 00Z MONDAY. AS THIS LOW SWEEPS EAST...AN AREA OF SNOW
(CURRENTLY IN SOUTHWEST ONTARIO AND ALSO ENTERING NORTHWEST
MINNESOTA) WILL SWEEP ACROSS THE UPPER GREAT LAKES LATE THIS
EVENING THROUGH EARLY SUNDAY MORNING. THE SYNOPTIC SNOW WILL BE
AIDED BY THE RIGHT REAR OF THE 110KT UPPER JET THAT SWEEPS ACROSS
TONIGHT. IN ADDITION...POCKET OF 800-600MB FGEN WILL SLIDE THROUGH
WITH THE 850/700MB TROUGH. THUS...EXPECT A PERIOD OF LIGHT SNOW TO
MOVE ACROSS MUCH OF UPPER MICHIGAN FROM WEST TO EAST. WITH THE BEST
FORCING OVER THE NORTHERN HALF OF THE CWA...EXPECT THE BEST SYNOPTIC
SNOWFALL THERE...WHICH WILL BE AIDED BY LAKE ENHANCEMENT. OVER THE
SOUTHERN HALF...ONLY EXPECT A LIGHT DUSTING TO AN INCH AWAY FROM THE
LAKE SUPERIOR INFLUENCES WITH SNOW RATIOS AROUND NORMAL VALUES OF
13-1.
AS FOR THE LAKE ENHANCEMENT...COLD AIR SURGING IN BEHIND THE LOW
(FALLING FROM RAP ANALYZED VALUES OF 0C FROM WEST-EAST OVER THE
CENTRAL U.P. AT 20Z TO -10 TO -16C AT 12Z SUNDAY AND -23C BY 00Z
MONDAY) WILL LEAD TO LAKE ENHANCEMENT FOR AREAS NEAR LAKE SUPERIOR
AS THE WIND DIRECTIONS BECOME FAVORABLE. THE WINDS WILL BE OUT OF
THE NORTHEAST INITIALLY THIS EVENING OVER WESTERN LAKE
SUPERIOR...BUT AS THE SURFACE/925MB LOW MOVES EAST-NORTHEAST THROUGH
NORTHEAST WISCONSIN AND SOUTH CENTRAL UPPER MICHIGAN TONIGHT...THE
WINDS WILL TRANSITION TO THE NORTH OVERNIGHT...NNW SUNDAY
MORNING...AND THEN NW SUNDAY AFTERNOON. THUS...EXPECT THE INITIAL
ENHANCEMENT TO OCCUR LATE IN THE EVENING OVER THE NE FAVORED
LOCATIONS AND THEN TRANSITION WITH THE WINDS INTO SUNDAY MORNING.
THESE STEADY BACKING WINDS WILL LIKELY BE ONE OF THE LIMITING
FACTORS TO HEAVIER SNOWFALL AMOUNTS. THE SECOND ITEM THAT SHOULD
KEEP SNOWFALL AMOUNTS IN THE LES ADVISORY CATEGORY WILL BE THE SHORT
PERIOD WHEN THE LAKE ENHANCEMENT AND LOW LEVEL TEMPERATURE PROFILE
FALL WITHIN THE DGZ. AT MOST LOCATIONS...IT APPEARS LIKE IT WILL
ONLY OCCUR FOR A 3 TO MAYBE 6HOUR PERIOD. THUS...EVEN THOUGH SNOW
RATIOS WILL QUICKLY RISE TO THE LOWER 20S...THEY WILL QUICKLY FALL
ONCE THE DEEPER MOISTURE DEPARTS AND THE INCREASING COLD AIR MOVES
THE CLOUD OUT OF THE DGZ. FINALLY...GUSTY WINDS MAY LIMIT SNOW
RATIOS FROM GROWING MUCH ABOVE 22/23-1 DURING THE FAVORED
PERIOD...EVEN THOUGH ALL OF THE CLOUD IS WITHIN THE DGZ.
OVERALL...ONLY MADE MINOR TWEAKS TO MUCH OF THE SNOWFALL FORECAST
FOR TONIGHT INTO SUNDAY MORNING...LARGELY WITH HANDLING THE TIMING
OF THE CHANGE OVER TO SNOW FROM NORTHWEST TO SOUTHEAST. THE FAVORED
HIGHER TERRAIN LOCATIONS WILL LIKELY SEE AMOUNTS THROUGH SUNDAY
MORNING IN THE 3-8INCH RANGE...WITH THE GREATEST AMOUNTS OVER THE
HURON MOUNTAINS WITH THE LONGER PERIOD OF FAVORABLE WIND
DIRECTIONS. THAT WOULD BE THE ONLY LOCATIONS WHERE SOME CONCERN OF
NEAR WARNING AMOUNT SNOW WOULD OCCUR...BUT THE SOCIETAL IMPACT WILL
BE LIMITED.
DEEPER MOISTURE FROM THE LOW PULLS OUT QUICKLY FROM WEST TO EAST ON
SUNDAY MORNING AND LEADS TO A TRANSITION TO PURE LAKE EFFECT. WITH
THAT DEEPER MOISTURE DEPARTING...MODELS ARE ONLY SHOWING MOISTURE
AND INVERSION HEIGHTS AROUND 4KFT...BUT WITH LAKE INDUCED
EQUILIBRIUM LEVELS AROUND 5-6KFT...COULD STILL BE SOME STRONGER SNOW
SHOWERS. BUT WITH COLDER AIR CONTINUING TO SURGE IN...MUCH OF THE
CLOUD LAYER WILL MOVE TO THE TOP OF OR ABOVE THE DGZ...WHICH SHOULD
LEAD TO A TRANSITION TO MORE OF COLUMN/PLATES. THEREFORE...WILL
CONTINUE THE IDEA OF LOWERING SNOW RATIOS TO THE HIGH TEENS OR
AROUND 20-1 FROM WEST TO EAST THROUGH THE DAY SUNDAY. THIS SHOULD
LEAD TO LESSER SNOWFALL AMOUNTS IN THE AFTERNOON...WHICH WILL STILL
BE AIDED BY SLOWLY BACKING WINDS TO THE NORTHWEST. OVERALL...HAVE
AFTERNOON AMOUNTS OF 1-2 INCHES IN MOST LOCATIONS...WITH SLIGHTLY
HIGHER VALUES OVER WESTERN ALGER COUNTY. THEREFORE...WILL KEEP LES
ADVISORIES AS IS...ALTHOUGH THE LONG TERM DID MAKE SOME ADJUSTMENTS
TO ALGER TO EXTEND INTO MONDAY. THINK THAT COVERS THE OVERALL IDEA
VERY WELL...SINCE THE NEGATIVES WITH SNOW RATIOS AND BACKING WINDS
SHOULD LIMIT THE POTENTIAL FOR 12HR SNOW AMOUNTS REACHING WARNING
VALUES.
THE COLD AIR SURGING IN WILL LEAD TO FALLING TEMPERATURES STARTING
LATE THIS EVENING OVER THE WEST AND PUSHING ACROSS THE REST OF THE
AREA THROUGH THE NIGHT. OVERNIGHT LOWS FOR TONIGHT AND HIGHS FOR
TOMORROW ARE FAIRLY TRICKY...AS THEY BOTH WILL LIKELY OCCUR DURING
THE TWO HOUR OVERLAP BETWEEN 12-14Z. THUS...TRIED TO FOCUS ON TEMPS
DURING THAT PERIOD TO USE FOR SIMILAR VALUES. WITH THE COLD AIR
CONTINUING TO SURGE IN THROUGH THE DAY ON SUNDAY...EXPECT STEADY OR
SLOWLY FALLING TEMPERATURES THROUGH THE REST OF THE DAY ON
SUNDAY. AFTERNOON VALUES OVER THE WEST WILL BE IN THE LOWER SINGLE
DIGITS ABOVE ZERO AND AROUND 10 DEGREES OVER THE EAST HALF.
FACTORING IN WIND CHILLS...TOMORROW AFTERNOON WILL FEEL ABOUT 50
DEGREES COLDER THAN THIS PAST AFTERNOON.
.LONG TERM...(SUNDAY NIGHT THROUGH SATURDAY)
ISSUED AT 445 PM EST SAT DEC 28 2013
SUN NIGHT INTO MONDAY...ENHANCED LOW-LEVEL CONVERGENCE FROM
DEVELOPING LAND BREEZES AND LAKE-INDUCED TROUGHING WILL FAVOR
ALGER...NRN SCHOOLCRAFT AND LUCE COUNTIES FOR POTENTIAL ADVISORY
CRITERIA SNOWFALL. LES ADVISORIES WILL THEN LIKELY BE NEEDED FOR
THAT PORTION OF THE NE CWA WITH ADDITIONAL ACCUMULATIONS IN THE 3 TO
8 INCH RANGE FROM SUN NIGHT INTO MON MORNING.
WINDS ARE EXPECTED TO STEADILY BACK FROM NNW SUN EVENING TO WRLY BY
EARLY MON AFTERNOON AS SFC HIGH PRESSURE SLIDES FROM THE NRN PLAINS
INTO THE MID MISSISSIPPI VALLEY. THE STEADILY BACKING WINDS WILL
TEND TO SPREAD LES ACCUMULATION AROUND KEEPING MOST AREAS ON THE
LOWER END OF ADVISORY CRITERIA. FAR ERN ALGER AND NRN LUCE WILL BE
THE EXCEPTION WHERE MODELS INDICATE A LONGER PERIOD OF ENHANCED
LOW-LVL CONVERGENCE PARTICULARLY LATE SUN NIGHT INTO MONDAY
WHICH WILL LIKELY PUSH SNOWFALL AMOUNTS ON THE HIGHER END OF
ADVISORY CRITERIA (NEAR 8"). THE VERY DRY COLD ARCTIC AIRMASS ALONG
WITH THE SHORTER FETCH INTO NW UPPER MI WILL MAKE IT LESS FAVORABLE
FOR SIGNIFICANT LES THERE. ADDITIONAL LES WILL BE MORE ON THE ORDER
OF 2 TO LOCALLY 5 INCHES FOR SUN NIGHT INTO MON MORNING SO DO NOT
ANTICIPATE A NEED TO EXTEND LES ADVISORY THERE BEYOND SUNDAY.
HOWEVER...SOME OF THE MESOSCALE MODELS INDICATE THAT LOW-LVL
CONVERGENCE COULD INCREASE AND SOME ENHANCEMENT IS POSSIBLE WITH THE
APPROACH OF THE NEXT CLIPPER SHORTWAVE WHICH SHOULD FOCUS SOME
LOCALLY HEAVIER LES BANDS AND HIGHER ACCUMS BACK OVER THE KEWEENAW
MON AFTERNOON INTO MON EVENING...BUT FOR NOW THIS IS JUST REFLECTED
IN THE FCST GRIDS AND NO HEADLINE IS NEEDED YET.
THE OTHER ISSUE FOR SUNDAY NIGHT INTO MONDAY MORNING WILL BE THE
BITTER COLD ARCTIC AIRMASS SPREADING OVER THE REGION. WITH 8H TEMPS
FROM -22C TO -24C AND WINDS BACKING OFFSHORE TO A MORE WRLY
DIRECTION...THE WESTERN INTERIOR OF THE FCST AREA PARTICULARLY ALONG
THE WI BDR WILL BE UNDER THE GUN FOR ADVISORY CRITERIA WIND CHILLS
OF 25 TO 35 BELOW SUNDAY NIGHT INTO MON MORNING. GIVEN THE FOCUS ON
THE PRESENT LES HEADLINES ELECTED TO HOLD OFF ON WIND CHILL
ADVISORIES FOR NOW...BUT NO DOUBT ONE WILL BE NEEDED FOR A GOOD
PORTION OF THE WESTERN INTERIOR SUN NIGHT INTO MON MORNING.
MON NIGHT-THU...AS MODELS SHOW THE POLAR VORTEX GRADUALLY SHIFTING
FROM HUDSON BAY TO NRN QUEBEC BY TUE EVENING...VERY COLD ARCTIC AIR
WILL DOMINATE THE UPPER GREAT LAKES THROUGH MIDWEEK. WITH 850 MB
TEMPS DROPPING INTO THE -24C TO -29C RANGE...LES WILL PERSIST FOR
LOCATIONS FAVORED BY NW TO WNW FLOW. MODELS IN GOOD AGREEMENT WITH
TIMING OF NEXT CLIPPER SHORTWAVE ACROSS THE AREA MON NIGHT INTO TUE
MORNING. THIS SHORTWAVE WILL REINFORCE ARCTIC AIR WHILE ALSO
SPREADING MID Q-VECT CONV AND DEEPER MOISTURE ACROSS THE REGION.
MODELS INDICATE THIS SHORTWAVE COULD PROVIDE ENHANCEMENT TO LES
WHILE ALSO SHARPENING LAKE-INDUCED TROFFING AND LOW-LVL CONVERGENCE
OVER ERN LAKE SUPERIOR. WHILE THE INFLUX OF COLDER -24 TO -27C 8H
TEMPS BY TUESDAY WILL EVENTUALLY LEAD TO POOR SNOW GROWTH AND
SMALLER SNOWFLAKES...THE WRF-ARW BUFR SNDG FOR GRAND MARAIS MON
NIGHT INTO EARLY TUE SHOWS A SOMEWHAT FAVORABLE SNOW GROWTH PROFILE
WITH THE DGZ INITIALLY INTERSECTING THE BETTER MODEL OMEGA FOCUSED
WITHIN THE CONVECTIVE BOUNDARY LAYER. THIS COULD INITIALLY LEAD TO
HIGHER SLR/S...FLUFFIER SNOW AND GREATER ACCUMULATIONS ESPECIALLY
FOR ERN ALGER AND LUCE COUNTIES. GIVEN THE ABOVE FAVORABLE FACTORS
AND POTENTIAL FOR ENHANCEMENT THERE IS A POTENTIAL FOR HIGH END
ADVISORY LES ACCUMS POSSIBLY PUSHING LES WARNING AMTS MON NIGHT INTO
TUE MORNING FOR ERN ALGER AND LUCE COUNTIES. AFTER TUESDAY...MODELS NOT
INDICATING ANY DISCERNIBLE CLIPPER SHORTWAVES FOR MIDWEEK AS 850 MB
TEMPS GENERALLY REMAIN IN THE -22 TO -26C RANGE. THE COLDER AIRMASS
WILL GENERALLY FAVOR SMALL SNOWFLAKES WITH THE ABSENCE OF
ENHANCEMENT/DEEPER MOISTURE WHICH WILL LIMIT OVERALL ACCUMULATIONS
BUT STILL LEAD TO LOW VISIBILITIES. OUTSIDE OF THE LES...SEVERE WIND
CHILLS CAN BE EXPECTED AT TIMES AS VALUES DROP INTO THE -20 TO -35
RANGE...MAINLY IN THE NIGHTTIME AND MORNING HRS.
MODELS SHOW SIGNS OF TRENDING TOWARD LESS AMPLIFIED PATTERN BY THE
END OF THE WEEK WITH WAA DEVELOPING BY FRI. AS SFC HIGH PRESSURE
SLIDES EAST LATE IN THE WEEK...BOTH THE ECMWF AND GFS DEVELOP AREA
OF LIGHT SNOW IN REGION OF WAA/ISENTROPIC ASCENT AHEAD OF A SHRTWV
MOVING DOWN FM NW ONTARIO. THIS SNOW LOOKS TO SPREAD INTO UPPER MI
LATE FRI OR FRI NIGHT. AS SYSTEM SNOW TAPERS OFF EARLY SAT...LIGHT
LES COULD DEVELOP LATE IN THE DAY AS WINDS SHIFT NORTHERLY BEHIND
FRONTAL PASSAGE.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT)
ISSUED AT 1226 AM EST SUN DEC 29 2013
PERIODS OF -SN/-SHSN/BLSN WITH IFR CONDITIONS IN THE GUSTY N FLOW IN
THE WAKE OF LO PRES SHIFTING TO THE E THRU THE CENTRAL GRT LKS WL
GIVE WAY TO MVFR CONDITIONS ON SUN AS STRONG SUBSIDENCE/DIMINISHING
WINDS WEAKEN THE SN/GUSTY WINDS/BLSN. THE MOST RAPID IMPROVEMENT WL
OCCUR AT CMX...WHERE THE EXPECTED N WIND DOES NOT PRESENT AS SGNFT
AN UPSLOPE WIND COMPONENT. BUT AS THE FLOW CONTINUES TO BACK TO THE
NW ON SUN AFTN/EVNG...IFR VSBYS WL REDVLP THERE WITH A MORE FVRBL
WIND. AT THE SAME TIME...THE DOWNSLOPE NATURE OF THE FLOW INTO SAW
WL CAUSE VFR CONDITIONS BY LATER IN THE DAY ON SUN.
&&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 419 PM EST SAT DEC 28 2013
WINDS TO STAY LIGHT UNTIL SFC LOW BRINGS TIGHTENING PRESSURE
GRADIENT TO WESTERN LAKE SUPERIOR THIS AFTERNOON. BY LATE
AFTERNOON...WILL SEE FREQUENT GALE FORCE GUSTS OVER WESTERN LAKE
SUPERIOR WITH NE GALES EXPECTED BY THE EVENING. AS THE SFC LOW
PASSES TO THE SE OF THE AREA OVERNIGHT...NORTH WINDS TO GRADUALLY
RELAX. MUCH COLDER AIR ARRIVING TONIGHT WILL PRODUCE HEAVY FREEZING
SPRAY AS WELL. WINDS GO BELOW 25 KNOTS SUNDAY AFTERNOON AND BELOW 20
KNOTS BY MONDAY AFTERNOON. WINDS REMAIN BELOW 20 KNOTS THROUGH THE
REMAINDER OF THE FORECAST.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
LAKE EFFECT SNOW ADVISORY UNTIL 7 PM EST /6 PM CST/ THIS EVENING
FOR MIZ001>005-009-084.
LAKE EFFECT SNOW ADVISORY FROM 1 PM THIS AFTERNOON TO 7 AM EST
MONDAY FOR MIZ085.
LAKE EFFECT SNOW ADVISORY UNTIL 1 PM EST MONDAY FOR MIZ006.
LAKE EFFECT SNOW ADVISORY FROM 7 PM THIS EVENING TO 1 PM EST
MONDAY FOR MIZ007.
LAKE SUPERIOR...
HEAVY FREEZING SPRAY WARNING UNTIL 1 AM EST WEDNESDAY FOR
LSZ265>267.
GALE WARNING UNTIL 7 AM EST /6 AM CST/ THIS MORNING FOR LSZ162-
263>266.
HEAVY FREEZING SPRAY WARNING UNTIL 1 AM EST /MIDNIGHT CST/
MONDAY FOR LSZ162-263-264.
HEAVY FREEZING SPRAY WARNING UNTIL 6 PM EST MONDAY FOR
LSZ248>251.
HEAVY FREEZING SPRAY WARNING UNTIL 7 PM EST /6 PM CST/ THIS
EVENING FOR LSZ240>247.
GALE WARNING UNTIL 5 AM EST /4 AM CST/ EARLY THIS MORNING FOR
LSZ240-241.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...SRF
LONG TERM...VOSS
AVIATION...KC
MARINE...SRF
AREA FORECAST DISCUSSION
NWS HASTINGS NE
1133 PM CST SAT DEC 28 2013
.SHORT TERM...(THIS EVENING THROUGH SUNDAY)
ISSUED AT 337 PM CST SAT DEC 28 2013
...A BRIEF BUT POTENT BLAST OF ARCTIC AIR AS TEMPS PLUNGE FROM
TODAY/S NEAR RECORD WARMTH...
ALOFT: PROGRESSIVE NW REMAINS IN PLACE. AN EMBEDDED POSITIVE-TILT
TROF WAS OVER THE NRN ROCKIES. THIS TROF WILL MOVE THRU HERE
TOMORROW...WITH NW FLOW TO FOLLOW.
SURFACE: LOW PRES HAS BEEN MIGRATING E ALONG AN ARCTIC COLD
FRONT...OUT OF THE DAKOTAS FROM THIS MORNING AND WAS OVER SWRN MN
AT 20Z. THE FRONT WAS SURGING S IN ITS WAKE AND IR SATELLITE
IMAGERY SUGGESTS THAT IT/S THRU THE SANDHILLS AND EXTENDS FROM
ALBION-LOUP CITY-LEXINGTON AT 20Z. THE FRONT SHOULD BE THRU THE
FCST AREA IN 6 HRS OR LESS...EXITING INTO CNTRL KS BY 9PM. STRONG
ARCTIC HIGH PRES BUILDS IN TONIGHT AS IT SLIDES INTO THE NRN
PLAINS. IT WILL WEAKEN TOMORROW AS IT CONTINUES DOWN THE MO RIVER
VALLEY.
UPDATED ADVISORY/HAZARDOUS WX OUTLOOK HAVE POSTED. GOSPER/DAWSON/
PHELPS COUNTIES ARE NOW INCLUDED. THE END TIME HAS ALSO BEEN MOVED
UP TO 3 AM...BUT ADVISORY COULD END UP BEING TERMINATED AS EARLY
AS 12 AM.
REST OF THIS AFTERNOON: WE PUT THE FINISHING TOUCHES ON ANOTHER
VERY NICE DAY FOR LATE DEC WITH NEAR-RECORD MUCH ABOVE NORMAL
WARMTH.
A CHECK OF GRI ASOS AT 335 PM VIA MODEM SHOWS A HIGH OF 62F. THE
FRONT HAS MOVED THRU AND THE TEMP IS DOWN TO 59F. CAME WITHIN 2F
OF TYING THE RECORD HIGH /64 IN 2002/.
WE HAVE BEEN WATCHING IMPRESSIVE PRES GRADIENT OVER ND/SD/MT/WY
TODAY WITH EQUALLY IMPRESSIVE WINDS. PEAK GUSTS OF 45-52 KTS HAVE
BEEN COMMON. THERE IS A CORE OF 40-55 KT WINDS AT 850 MB
COINCIDENT WITH THESE WINDS. THE RAPID CITY 88D CONFIRMS ITS
PRESENCE.
EXPECT DOWNWARD TRANSFER IN VERY STEEP LAPSE RATES/COLD AIR
ADVECTION AS THIS JET CORE DROPS INTO THE FCST AREA.
THE STRONGEST WINDS WILL OCCUR IN THE 6-8 HRS IMMEDIATELY
FOLLOWING PASSAGE OF THE COLD FRONT /IE BEFORE MIDNIGHT/.
VALENTINE HAD A PEAK WIND OF 45 KTS AT 218 PM.
THE WINDIEST LOCATIONS WILL BE ALONG AND N OF HWY 92. RAP TIME-
HEIGHT CROSS SECTIONS SHOW 45 KTS DOWN TO 1K FT WITH A CORE OF 50
KTS DOWN TO 1800 FT FROM 9PM-12AM. 18Z NAM HAS 52 KTS BUT ONLY AS
LOW AS 2K FT 6PM-9PM. BOTTOM LINE...WOULD NOT BE SURPRISED TO SEE
G50-55 MPH IN THESE AREAS THIS EVE.
15Z SREF PROBABILITIES FOR MEAN WINDS 30 MPH OR GREATER ARE
HIGHEST OVER CNTRL NEB N INTO THE SANDHILLS 6PM-11PM. THIS IS
WHERE THE ADVISORY HAS THE BEST CHANCE OF VERIFYING.
TONIGHT: WINDY AND TURNING MUCH COLDER. BECOMING MOSTLY CLOUDY AS
THE 900-850 MB LAYER COOLS TO SATURATION. EXTENSIVE MID-HIGH
CLOUDS WILL ALSO INVADE. LOW TEMPS ROUGHLY 8F COLDER THAN NORMAL.
TOMORROW: DECREASING CLOUDS AND WINDS. TEMPS MUCH COLDER THAN
NORMAL /BY 15-20F/.
.LONG TERM...(SUNDAY NIGHT THROUGH SATURDAY)
ISSUED AT 332 PM CST SAT DEC 28 2013
A 1035MB SURFACE HIGH PRESSURE SYSTEM WILL BUILD SOUTH ALONG THE
MISSOURI RIVER SUNDAY EVENING...AND EXPECT TEMPERATURES WILL DROP
OFF RATHER QUICKLY FOR THE FIRST PART OF THE NIGHT. AS THE SFC
RIDGE AXIS WEAKENS AND SHIFTS EASTWARD SUNDAY NIGHT...RETURN FLOW
SETS UP AND THE AIRMASS BEGINS TO MODERATE AND TEMPERATURES SHOULD
TREND UP HEADING INTO MONDAY MORNING.
THE UPPER TROUGH AXIS WILL TRANSLATE EAST/NORTHEASTWARD FOR THE
FIRST PART OF THE WEEK...WHICH ALLOWS FOR A REBOUND IN
TEMPERATURES FOR OUR AREA AS HEIGHTS RISE BEHIND THE SYSTEM. THIS
BEING SAID IT IS IMPORTANT TO NOTE THAT THE COLD AIR IS NOT THAT
FAR AWAY AND IF THE BAROCLINIC ZONE SHIFTS FARTHER SOUTH AND
WEST...IT WILL BE ACROSS US AND TEMPS WILL BE COLDER. THE BIGGEST
CHANGE IN THE FORECAST COMES IN THE TUESDAY TIME FRAME AS SEVERAL
OF THE LATEST OPERATIONAL MODELS NO LONGER BACK A COLD FRONT AS
FAR SOUTH INTO SC NEBRASKA AS PREVIOUS RUNS. MODELS ARE IN PRETTY
GOOD AGREEMENT THAT THE COLD AIR AND STRATUS WILL BE ORIENTED
ACROSS SOUTH DAKOTA/NORTHERN IOWA AND PERHAPS FAR NORTHERN
NEBRASKA THROUGH THE DAY...ALTHOUGH A COLD FRONT DOES ADVANCE
SOUTH IN THE AFTN. HAVE RAISED TEMPERATURES FOR TUESDAY...BUT WILL
NEED TO MONITOR THERMAL AND CLOUD FIELDS CLOSELY AS THE 12Z ECMWF
REMAINS COLDER THAN GFS/GEM/NAM IN THIS TIME FRAME.
A COLD FRONT PUSHES SOUTH TUESDAY/NEW YEARS EVE NIGHT AND MODELS
ARE NOT OVERLY ROBUST IN GENERATING PCPN WITH THIS BUT DID
MAINTAIN SOME VERY LOW POPS FOR LIGHT SNOW ACROSS OUR NORTHEAST
ZONES. LIGHT WINTRY PCPN IS POSSIBLE ON WEDNESDAY/NEW YEARS DAY AS
A 120KT JET NOSES SOUTH ALONG THE ROCKIES/HIGH PLAINS REGION AND
DEEPENS A TROUGH ACROSS THE PLAINS AND UPPER MIDWEST. COLDER AIR
ADVECTS SOUTH AND A BAND OF FRONTOGENETIC SNOWFALL IS POSSIBLE
INTO WEDNESDAY NIGHT.
THURSDAY WILL BE THE TRANSITION DAY BETWEEN THE COLD AIR AT THE
MIDDLE OF THE WEEK AND A WARMING TREND FOR THE END OF THE WEEK.
THE UPPER TROUGH AND COLD AIR ONCE AGAIN SLIDE EAST THURSDAY WITH
HEIGHTS RISING/MODERATING TEMPS IN ITS WAKE. FRIDAY IS SHAPING UP
TO BE MILD AGAIN WITH ABOVE NORMAL TEMPS IN SUBTLE RIDGING ALOFT.
SATURDAY TEMPS WILL BE DEPENDENT ON COLD FRONTAL TIMING WITH THE
GFS QUICKER WITH THE FRONT PASSAGE THAN THE ECMWF...AND GIVEN
MODEL DIFFERENCES DID NOT DEVIATE MUCH FROM INIT FOR DAY 7.
&&
.AVIATION...(FOR THE 06Z KGRI TAF THROUGH 06Z SUNDAY NIGHT)
ISSUED AT 1125 PM CST SAT DEC 28 2013
MVFR CIGS WILL CONTINUE TO STREAM ACROSS THE TERMINAL THROUGH THE
OVERNIGHT HOURS WITH A FEW BRIEF LIGHT FLURRIES ALSO POSSIBLE. IN
ADDITION...EXPECT STRONG NORTHERLY WINDS TO CONTINUE...
OCCASIONALLY GUSTING TO NEAR 40 KTS...THROUGH ABOUT 29/12.
THEREAFTER...EXPECT THE PRESSURE GRADIENT TO BEGIN TO
WEAKEN...AND WINDS TO DIMINISH SLOWLY THROUGH THE DAY...
EVENTUALLY BECOMING LIGHT AND VARIABLE BY LATE AFTERNOON.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...WIND ADVISORY UNTIL 3 AM CST SUNDAY FOR NEZ039>041-046>049-
060>064-072>077.
KS...NONE.
&&
$$
SHORT TERM...HALBLAUB
LONG TERM...FAY
AVIATION...ROSSI
AREA FORECAST DISCUSSION
NWS NORTH PLATTE NE
1128 PM CST SAT DEC 28 2013
.UPDATE...
ISSUED AT 1118 PM CST SAT DEC 28 2013
SURFACE WINDS CONTINUE TO DECREASE ACROSS THE WEST WITH THE WIND
ADVISORY FOR AREAS WEST OF HIGHWAY 83 TO EXPIRE AT MIDNIGHT. THEN
MAIN CONCERN WILL BE THE SURFACE WINDS OVER THE NORTH CENTRAL
THROUGH 3 AM AND HOW LOW TEMPERATURES WILL GO BY DAYBREAK.
SATELLITE SHOWS CLOUD TOPS WARMING WITH CLEARING TO INFLUENCE HOW
LOW TEMPERATURES WILL GO WITH NEW GUIDANCE SHOWING ANOTHER 2 TO 3
DEGREES COLDER ACROSS THE NORTH. FOR NOW NO BIG CHANGES AS THE COMBINATION
OF COLDER AIR AND WINDS WILL DRIVE WIND CHILL VALUES DOWN. PLEASE REFER
TO WIND CHILL ADVISORY FOR DETAILS.
UPDATE ISSUED AT 918 PM CST SAT DEC 28 2013
SURFACE WINDS DIMINISHING ACROSS THE PANHANDLE AND SOUTHWEST TO
CANCEL THE WIND ADVISORY FOR AREAS GENERALLY WEST OF A LINE FROM
KILGORE TO MULLEN...TRYON..AND BRADY. FURTHER EAST STRONG WINDS
WILL LINGER A FEW MORE HOURS THEN DIMINISH ACROSS THE NORTH
CENTRAL EARLY MORNING.
&&
.SHORT TERM...(THIS EVENING THROUGH SUNDAY)
ISSUED AT 706 PM CST SAT DEC 28 2013
FORECAST UPDATED AS SNOW SHOWERS A LITTLE MORE AGRESSIVE AND
FURTHER SOUTH. THE SNOW SHOWERS ARE MOVING SOUTH AROUND 25 MPH
WITH LOW POPS INTRODUCED THROUGHOUT THROUGH MIDNIGHT AND TRENDED
TO THE LATEST RUC SOLUTION. NO ACCUMULATIONS EXPECTED ALTHOUGH
VISIBILITY MAY BE BRIEFLY REDUCED AS SNOW SHOWERS MOVE ACROSS
THROUGH MIDNIGHT.
.LONG TERM...(SUNDAY NIGHT THROUGH SATURDAY)
ISSUED AT 331 PM CST SAT DEC 28 2013
A PROGRESSIVE PATTERN CONTINUES IN THE NORTHWEST FLOW ACROSS THE
PLAINS THROUGH MOST OF NEXT WEEK.
THE NEXT STORM SYSTEM FROM THE CANADIAN ROCKIES COMES THROUGH
WESTERN NEBRASKA TUESDAY. THERE IS SOME ISENTROPIC LIFT INDICATED IN
THE 290-300K LAYER...BUT MOISTURE IS LACKING EVERYWHERE EXCEPT THE
AREA NORTH AND WEST OF ONEILL.
ANOTHER PULSE IS ON THE WAY FOR TUESDAY NIGHT THROUGH WEDNESDAY.
THAT ONE ALSO SHOWS ISENTROPIC LIFT IN THE 290-300K LAYER WITH SOME
FRONTOGENETIC ENHANCEMENT IN CENTRAL AND NORTH CENTRAL NEBRASKA.
THOUGH MOISTURE IS A LITTLE BETTER...IT IS STILL FAIRLY DRY IN THE
LOWER LAYERS. ALSO...THERE ARE SIGNIFICANT DIFFERENCES IN THE
LOCATIONS INDICATED IN THE THREE MEDIUM/LONG RANGE MODELS (THE
ECMWF...GEMNH AND US GFS)...SO WE WILL KEEP THE PROBABILITY LOW FOR
NOW.
ANOTHER SYSTEM IS EXPECTED TO DEVELOP IN COLORADO FRIDAY OR
SATURDAY...BUT THE UNCERTAINTY WITH THAT ONE IS HIGH.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT)
ISSUED AT 1125 PM CST SAT DEC 28 2013
MARGINAL VISUAL FLIGHT RULES CONTINUE OVERNIGHT AT THE KVTN AND
KLBF TERMINALS. SATELLITE SHOWS CLOUD TOPS WARMING ACROSS THE
NORTHWEST WITH CEILING LIFTING BEYOND 12Z FOR VISUAL FLIGHT RULES
AT KLBF AND KVTN BEYOND 15Z.
&&
.LBF WATCHES/WARNINGS/ADVISORIES...
WIND CHILL ADVISORY FROM 3 AM CST /2 AM MST/ TO 9 AM CST /8 AM
MST/ SUNDAY FOR NEZ004>010-023>029-094.
WIND ADVISORY UNTIL 3 AM CST SUNDAY FOR NEZ007-010-027>029-038.
WIND ADVISORY UNTIL MIDNIGHT CST TONIGHT FOR NEZ005-006-008-009-
025-026-037.
&&
$$
UPDATE...KECK
SHORT TERM...KECK
LONG TERM...SPRINGER
AVIATION...KECK
AREA FORECAST DISCUSSION
NWS BINGHAMTON NY
311 AM EST SUN DEC 29 2013
.SYNOPSIS...
CLOUDS WILL BE ON THE INCREASE THIS MORNING WITH PRECIPITATION
GRADUALLY OVERSPREADING BY AFTERNOON AS A FAST MOVING STORM SYSTEM
MOVES UP THE EAST COAST. PRECIPITATION INITIALLY IN THE FORM OF
RAIN WILL CHANGEOVER TO SNOW BY LATE AFTERNOON AND EARLY
EVENING ACROSS MOST AREAS...WITH THE HEAVIEST ACCUMULATIONS EXPECTED
ACROSS THE WESTERN CATSKILLS. AFTER THIS STORM PASSES...MUCH
COOLER AIR WILL SETTLE ACROSS THE REGION AS ARCTIC HIGH PRESSURE
BUILDS SOUTH FROM CANADA. THE NEXT CHANCE FOR ORGANIZED SNOWFALL
WILL COME ON TUESDAY AS A STORM SYSTEM PASSES TO OUR NORTH.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
115 AM UPDATE...
AS OF 1 AM...TEMPERATURES WERE BEGINNING TO WARM WEST OF THE I-81
CORRIDOR AS WARM AIR ADVECTION INCREASES IN ADVANCE OF A STORM
SYSTEM MOVING THROUGH THE WESTERN AND CENTRAL GREAT LAKES. THAT
SAID...MAIN ATTENTION REMAINS WELL TO OUR SOUTH THIS MORNING AS
WATER VAPOR SHOWS A FAIRLY COMPACT STORM SYSTEM RAPIDLY LIFTING
THROUGH THE DEEP SOUTH. THIS FEATURE WILL CONTINUE MOVING NORTH
ALONG THE EAST COAST TODAY WITH PRECIPITATION EXPECTED TO
GRADUALLY OVERSPREAD THE REGION LATE THIS MORNING AND EARLY
AFTERNOON. STILL TRYING TO ASCERTAIN KEY IMPACTS FROM THIS SYSTEM
HOWEVER WITH THE CURRENT LINE OF THOUGHT BEING THAT PRECIP WILL
FALL MOSTLY IN THE FORM OF RAIN EARLY ON...WITH A GRADUAL
CHANGEOVER TO SNOW AS THE SYSTEM DEEPENS OVER SOUTHERN NEW ENGLAND
AND PULLS AWAY FROM THE AREA. FCST MODELS STILL DISAGREE ON THE
THERMAL STRUCTURE OF THE ATMOSPHERE WITH THE NAM NOW THE COOLEST
OF ALL SOLUTIONS. IF THIS MODEL WERE TO VERIFY...PRECIP WOULD
MAINLY BE IN THE FORM OF SNOW...WHILE THE GFS AND RUC SUGGEST MUCH
OF THE PRECIP WILL BE IN THE FORM OF RAIN. IN ANY EVENT...MANY
DECISIONS STILL NEED TO BE MADE BEFORE THE 430 AM UPDATE.
PREVIOUS NEAR TERM DISCUSSION...
CLOUDS OVER THE NORTHERN PORTION OF THE
FORECAST AREA SWEPT OUT TO THE NORTHEAST. A LITTLE FOG DEVELOPED
IN THE ROME AREA BUT SHOULD ONLY LAST A FEW HOURS AT BEST. HIGH
CIRRUS AHEAD OF THE NEXT WEATHER SYSTEM HAVE RAPIDLY MOVED IN FROM
THE SOUTHWEST ACROSS NE PA AND CENTRAL NY. HAVE MADE MINOR
ADJUSTMENT TO THE FORECAST FOR OVERNIGHT. TEMPERATURES ARE RUNNING
WARMER ON THE HILLS WITH COLDER IN THE VALLEYS. VALLEYS SAW A
QUICK DROP IN TEMPS UNDER CLEAR SKIES ONCE THE SUN WAS LOW TO THE
HORIZON.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH TUESDAY/...
INTRSTG WX EVENT APRCHG IN THE SHRT TERM AS A DVLPG LOW MVES UP
THE EAST CST. PLENTY OF COLD AIR AVBL BUT SYSTEM IS BLOCKED FROM
GRABBING THE COLD AIR...AT LEAST AT THE BEGINNING...MAINLY DUE TO
A LACK OF PHASING WITH A NRN STREAM SYSTEM RIDING ALONG THE ARCTIC
FNT OVER SRN CANADA. EVENTUALLY...SOME EVAPORATIONAL COOLING AND A
BIT OF COLDER AIR ALLOWS THE PCPN TO FALL AS SNOW VERY LATE IN THE
DAY SUN...AND AS THE STORM PULLS OUT SUN NGT. AS THE PCPN MVES
IN...A LL WARM LYR KEEPS THE PCPN AS RAIN UNTIL A TRICKY AND DEEP
ISOTHERMAL LYR NEAR FRZG DVLPS LATE IN THE DAY. THIS WILL
EVENTUALLY ALLOW A CHG OVER TO SNOW...PRBLY OVER THE HIER
ELEVATIONS IN NY FIRST...ESP THE WRN CATS AND PARTS OF THE FINGER
LAKES. HWVR...AS THE SFC REMAINS RGT NEAR FRZG...ACCUMULATION OF
SNOW WILL BE SLOW AT FIRST. THEN...OVRNGT...A QUICK CPL INCHES
PSBL. HWVR...A QUICKER CHG OVER COULD BOOST ACCUMS TO NEARER 4
INCHES.
CAA CONTS ON MON WITH H8 TEMPS DROPPING TO -14C BY LATE IN THE
DAY. HWVR...SIGNIFICANT SHEAR SHD LIMT LE TO SCT SNOW
SHWRS...MAINLY OVER THE FINGER LAKES AND WRN SUSQ REGION.
SFC HIPRES BLDS IN FOR TUE KEEPING CONDS GNRLY DRY OTR THAN SOME
LGT LE.
MODEL GUID CONTD TO BE IN DECENT AGREEMENT THRU THE PD RESULTING
IN HIER CONFIDENCE IN TEMPS AND POP FCSTS.
&&
.LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/...
310 AM UPDATE...MEDIUM RANGE MODELS CONTINUE TO SHOW A POSITIVE
PNA PATTERN THROUGH THE PERIOD WITH A WESTERN RIDGE AND EASTERN
TROF. MODELS CONTINUE TO SHOW A FAIRLY STRONG QUICK MOVING SYSTEM
THAT TRACKS FROM THE MID WEST ACROSS THE OHIO VALLEY THEN OFF THE
MID ATLANTIC COAST WED NIGHT THROUGH THURSDAY EVENING. INCREASED
POPS INTO THE HIGH CHC CATEGORY DURING THIS PERIOD WITH SEVERAL
INCHES OF SNOW POSSIBLE FOR THE FORECAST AREA. ONCE THIS SYSTEM
DEPARTS A VERY COLD AIRMASS WILL SETTLE OVER THE REGION AS SFC
HIGH PRES IN EASTERN CANADA PROVIDES A N/NE FLOW. T85 DROPS INTO
THE -20C/-25C RANGE FRIDAY/FRIDAY NIGHT RESULTING IN MAXES OF 5 TO
15 DEGREES AND LOWS AROUND ZERO.
PREVIOUS DISC...
PNA PTRN PREVAILS...AND FOLLOWED WPC GUIDANCE. HOWEVER...CHGS
WERE MADE TO THE TUE NGT/WED TIME FRAME WITH MORE CLDS AND HIGHER
POPS AS MDLS SHOW DVLPMNT OF LGT OVERRUNNING PCPN ASSCD WITH A
S/WV SCOOTING FROM THE OH VLY INTO THE NRN MID ATLC. AFTER THIS
TIME...DIFFS ARISE WITH LATE WEEK SYSTEM...WITH GFS SUGGESTING
MORE OF IMPACT ON THE FCST AREA. 00Z EURO KEEPS THE BULK OF THIS
ACTION WELL SOUTH OF THE RGN. COLD TEMPS WITH HIGHS IN THE TEENS AND
LOWS DROPPING INTO THE SINGLE DIGITS (COLDER IN NRN SXNS) BEFORE
MODERATING LATE IN THE PD.
&&
.AVIATION /08Z SUNDAY THROUGH THURSDAY/...
LOW PRES WILL TRACK THROUGH THE MID ATLANTIC REGION THIS MORNING
THEN ALONG THE EAST COAST LATE THIS AFTERNOON THROUGH THE EVENING
HOURS. EXCEPT FOR MVFR/IFR FOG AT KRME THROUGH DAYBREAK, VFR
CONDITIONS WILL CONTINUE AS MID/HIGH CLOUDS THICKEN. LIGHT RAIN
WITH MVFR CONDITIONS WILL SPREAD FROM SOUTH TO NORTH ACROSS THE
TERMINALS DURING THE LATE MORNING AND EARLY AFTERNOON PERIOD.
AT KITH/KBGM/KELM, MIXED RAIN/SNOW WILL OCCUR BEGINNING AROUND
21Z. CONFIDENCE HERE IS LOW FOR P-TYPE DUE TO MODEL DIFFERENCES
AND BOUNDARY LAYER TEMPS VERY CLOSE TO FREEZING. AT KRME/KSYR, BY
03Z CAA WILL ALLOW ANY REMAINING PRECIP TO CHANGE TO MVFR SNOW
SHOWERS. AT KITH/KBGM/KELM, AFTER 03Z PRECIP WILL END BUT MVFR
CIGS WILL PERSIST. AT KAVP, IFR CONDITIONS IN LIGHT TO MODERATE
RAIN WILL PREVAIL THROUGH THE MID/LATE AFTERNOON THEN END AROUND
00Z BUT MVFR CIGS WILL CONTINUE.
LIGHT WINDS EARLY THIS MORNING BECOMING S/SE AROUND 5 KNOTS
GRADUALLY SHIFTING TO THE SOUTHWEST THEN WEST LATE IN THE TAF
PERIOD.
OUTLOOK...
MON...SCT MVFR IN -SHSN ACRS CNTRL NY.
MON NGT...MAINLY VFR.
TUE...SCT MVFR IN -SHSN ACRS CNTRL NY.
TUE NGT/WED...IFR/MVFR IN -SHSN.
THU...IFR SNOW DEVELOPING.
&&
.BGM WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NY...NONE.
&&
$$
SYNOPSIS...CMG
NEAR TERM...BMW/CMG
SHORT TERM...DGM
LONG TERM...RRM
AVIATION...RRM
AREA FORECAST DISCUSSION
NWS BINGHAMTON NY
120 AM EST SUN DEC 29 2013
.SYNOPSIS...
CLOUDS WILL BE ON THE INCREASE THIS MORNING WITH PRECIPITATION
GRADUALLY OVERSPREADING BY AFTERNOON AS A FAST MOVING STORM SYSTEM
MOVES UP THE EAST COAST. PRECIPITATION INITIALLY IN THE FORM OF
RAIN WILL CHANGEOVER TO SNOW BY LATE AFTERNOON AND EARLY
EVENING ACROSS MOST AREAS...WITH THE HEAVIEST ACCUMULATIONS EXPECTED
ACROSS THE WESTERN CATSKILLS. AFTER THIS STORM PASSES...MUCH
COOLER AIR WILL SETTLE ACROSS THE REGION AS ARCTIC HIGH PRESSURE
BUILDS SOUTH FROM CANADA. THE NEXT CHANCE FOR ORGANIZED SNOWFALL
WILL COME ON TUESDAY AS A STORM SYSTEM PASSES TO OUR NORTH.
&&
.NEAR TERM /THROUGH TODAY/...
115 AM UPDATE...
AS OF 1 AM...TEMPERATURES WERE BEGINNING TO WARM WEST OF THE I-81
CORRIDOR AS WARM AIR ADVECTION INCREASES IN ADVANCE OF A STORM
SYSTEM MOVING THROUGH THE WESTERN AND CENTRAL GREAT LAKES. THAT
SAID...MAIN ATTENTION REMAINS WELL TO OUR SOUTH THIS MORNING AS
WATER VAPOR SHOWS A FAIRLY COMPACT STORM SYSTEM RAPIDLY LIFTING
THROUGH THE DEEP SOUTH. THIS FEATURE WILL CONTINUE MOVING NORTH
ALONG THE EAST COAST TODAY WITH PRECIPITATION EXPECTED TO
GRADUALLY OVERSPREAD THE REGION LATE THIS MORNING AND EARLY
AFTERNOON. STILL TRYING TO ASCERTAIN KEY IMPACTS FROM THIS SYSTEM
HOWEVER WITH THE CURRENT LINE OF THOUGHT BEING THAT PRECIP WILL
FALL MOSTLY IN THE FORM OF RAIN EARLY ON...WITH A GRADUAL
CHANGEOVER TO SNOW AS THE SYSTEM DEEPENS OVER SOUTHERN NEW ENGLAND
AND PULLS AWAY FROM THE AREA. FCST MODELS STILL DISAGREE ON THE
THERMAL STRUCTURE OF THE ATMOSPHERE WITH THE NAM NOW THE COOLEST
OF ALL SOLUTIONS. IF THIS MODEL WERE TO VERIFY...PRECIP WOULD
MAINLY BE IN THE FORM OF SNOW...WHILE THE GFS AND RUC SUGGEST MUCH
OF THE PRECIP WILL BE IN THE FORM OF RAIN. IN ANY EVENT...MANY
DECISIONS STILL NEED TO BE MADE BEFORE THE 430 AM UPDATE.
PREVIOUS NEAR TERM DISCUSSION...
CLOUDS OVER THE NORTHERN PORTION OF THE
FORECAST AREA SWEPT OUT TO THE NORTHEAST. A LITTLE FOG DEVELOPED
IN THE ROME AREA BUT SHOULD ONLY LAST A FEW HOURS AT BEST. HIGH
CIRRUS AHEAD OF THE NEXT WEATHER SYSTEM HAVE RAPIDLY MOVED IN FROM
THE SOUTHWEST ACROSS NE PA AND CENTRAL NY. HAVE MADE MINOR
ADJUSTMENT TO THE FORECAST FOR OVERNIGHT. TEMPERATURES ARE RUNNING
WARMER ON THE HILLS WITH COLDER IN THE VALLEYS. VALLEYS SAW A
QUICK DROP IN TEMPS UNDER CLEAR SKIES ONCE THE SUN WAS LOW TO THE
HORIZON.
&&
.SHORT TERM /TONIGHT THROUGH TUESDAY/...
INTRSTG WX EVENT APRCHG IN THE SHRT TERM AS A DVLPG LOW MVES UP
THE EAST CST. PLENTY OF COLD AIR AVBL BUT SYSTEM IS BLOCKED FROM
GRABBING THE COLD AIR...AT LEAST AT THE BEGINNING...MAINLY DUE TO
A LACK OF PHASING WITH A NRN STREAM SYSTEM RIDING ALONG THE ARCTIC
FNT OVER SRN CANADA. EVENTUALLY...SOME EVAPORATIONAL COOLING AND A
BIT OF COLDER AIR ALLOWS THE PCPN TO FALL AS SNOW VERY LATE IN THE
DAY SUN...AND AS THE STORM PULLS OUT SUN NGT. AS THE PCPN MVES
IN...A LL WARM LYR KEEPS THE PCPN AS RAIN UNTIL A TRICKY AND DEEP
ISOTHERMAL LYR NEAR FRZG DVLPS LATE IN THE DAY. THIS WILL
EVENTUALLY ALLOW A CHG OVER TO SNOW...PRBLY OVER THE HIER
ELEVATIONS IN NY FIRST...ESP THE WRN CATS AND PARTS OF THE FINGER
LAKES. HWVR...AS THE SFC REMAINS RGT NEAR FRZG...ACCUMULATION OF
SNOW WILL BE SLOW AT FIRST. THEN...OVRNGT...A QUICK CPL INCHES
PSBL. HWVR...A QUICKER CHG OVER COULD BOOST ACCUMS TO NEARER 4
INCHES.
CAA CONTS ON MON WITH H8 TEMPS DROPPING TO -14C BY LATE IN THE
DAY. HWVR...SIGNIFICANT SHEAR SHD LIMT LE TO SCT SNOW
SHWRS...MAINLY OVER THE FINGER LAKES AND WRN SUSQ REGION.
SFC HIPRES BLDS IN FOR TUE KEEPING CONDS GNRLY DRY OTR THAN SOME
LGT LE.
MODEL GUID CONTD TO BE IN DECENT AGREEMENT THRU THE PD RESULTING
IN HIER CONFIDENCE IN TEMPS AND POP FCSTS.
&&
.LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/...
PNA PTRN PREVAILS...AND FOLLOWED WPC GUIDANCE. HOWEVER...CHGS
WERE MADE TO THE TUE NGT/WED TIME FRAME WITH MORE CLDS AND HIGHER
POPS AS MDLS SHOW DVLPMNT OF LGT OVERRUNNING PCPN ASSCD WITH A
S/WV SCOOTING FROM THE OH VLY INTO THE NRN MID ATLC. AFTER THIS
TIME...DIFFS ARISE WITH LATE WEEK SYSTEM...WITH GFS SUGGESTING
MORE OF IMPACT ON THE FCST AREA. 00Z EURO KEEPS THE BULK OF THIS
ACTION WELL SOUTH OF THE RGN. COLD TEMPS WITH HIGHS IN THE TEENS AND
LOWS DROPPING INTO THE SINGLE DIGITS (COLDER IN NRN SXNS) BEFORE
MODERATING LATE IN THE PD.
&&
.AVIATION /06Z SUNDAY THROUGH THURSDAY/...
LOW PRES WILL TRACK THROUGH THE MID ATLANTIC REGION THIS MORNING
THEN ALONG THE EAST COAST LATE THIS AFTERNOON THROUGH THE EVENING
HOURS. EXCEPT FOR MVFR/IFR FOG AT KRME THROUGH DAYBREAK, VFR
CONDITIONS WILL CONTINUE AS MID/HIGH CLOUDS THICKEN. LIGHT RAIN
WITH MVFR CONDITIONS WILL SPREAD FROM SOUTH TO NORTH ACROSS THE
TERMINALS DURING THE LATE MORNING AND EARLY AFTERNOON PERIOD.
AT KITH/KBGM/KELM, MIXED RAIN/SNOW WILL OCCUR BEGINNING AROUND
21Z. CONFIDENCE HERE IS LOW FOR P-TYPE DUE TO MODEL DIFFERENCES
AND BOUNDARY LAYER TEMPS VERY CLOSE TO FREEZING. AT KRME/KSYR, BY
03Z CAA WILL ALLOW ANY REMAINING PRECIP TO CHANGE TO MVFR SNOW
SHOWERS. AT KITH/KBGM/KELM, AFTER 03Z PRECIP WILL END BUT MVFR
CIGS WILL PERSIST. AT KAVP, IFR CONDITIONS IN LIGHT TO MODERATE
RAIN WILL PREVAIL THROUGH THE MID/LATE AFTERNOON THEN END AROUND
00Z BUT MVFR CIGS WILL CONTINUE.
LIGHT WINDS EARLY THIS MORNING BECOMING S/SE AROUND 5 KNOTS
GRADUALLY SHIFTING TO THE SOUTHWEST THEN WEST LATE IN THE TAF
PERIOD.
OUTLOOK...
MON...SCT MVFR IN -SHSN ACRS CNTRL NY.
MON NGT...MAINLY VFR.
TUE...SCT MVFR IN -SHSN ACRS CNTRL NY.
TUE NGT/WED...IFR/MVFR IN -SHSN.
THU...IFR SNOW DEVELOPING.
&&
.BGM WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NY...NONE.
&&
$$
SYNOPSIS...CMG
NEAR TERM...BMW/CMG
SHORT TERM...DGM
LONG TERM...
AVIATION...RRM
AREA FORECAST DISCUSSION
NWS RALEIGH NC
306 AM EST SUN DEC 29 2013
.SYNOPSIS...A LOW PRESSURE SYSTEM WILL TRACK ACROSS THE AREA
TODAY...FOLLOWED BY THE ATTENDANT COLD FRONT SUNDAY NIGHT. ANOTHER
UPPER LEVEL DISTURBANCE WILL CROSS THE REGION MONDAY NIGHT.
&&
.NEAR TERM /THROUGH TODAY/...
AS OF 250 AM SUNDAY...
AN UPPER LOW OVER THE LOWER MISSISSIPPI RIVER VALLEY WILL CONTINUE
TO LIFT NORTHEAST TODAY...DEAMPLIFYING AS IT BECOMES INCREASINGLY
NEGATIVELY TILTED. THE ASSOCIATED DCVA AND 50-60 LOW LEVEL JET WILL
DEEPEN AND ACCELERATE A SURFACE LOW...CURRENTLY DEVELOPING OVER THE
FLORIDA PANHANDLE...TOWARD THE DELMARVA AREA TODAY.
NOT A LOT OF CHANGES TO MAKE TO THE CURRENT FORECAST. AREAS OF
LIGHT RAIN OVER SPREADING THE AREA ARE CREATING AN IN-SITU COLD AIR
DAMMING AIRMASS AND STRENGTHENING THE STABILITY ACROSS THE CWA.
MODELS HAVE TRENDED A LITTLE EAST WITH THE TRACK OF THE SURFACE
LOW...ESPECIALLY THE GFS...THOUGH NOT AS MUCH AS ONE MIGHT EXPECT IF
THEY ARE CATCHING ONTO THE CAD AIRMASS. A CONSENSUS WOULD TRACK THE
LOW UP THE I-95 CORRIDOR BETWEEN 15Z AND 18Z. THE COASTAL WARM
FRONT AND 55-65F DEWPOINT AIR ALONG THE CAROLINA COAST WILL SURGE
INLAND AS PRESSURES BEGIN TO FALL...BUT IT APPEARS THE BETTER
MARITIME AIRMASS THAT WOULD LEAD TO BETTER DESTABILIZATION AND
SEVERE THREAT WILL STAY ALONG THE COAST...HINDERED BY THE STABLE CAD
AIRMASS. STILL..THERE MAY BE A BRIEF PERIOD (15-18Z) WHERE 250-500
J/KG OF NEAR SURFACE BASED CAPE CAN PHASE WITH HODOGRAPHS FAVORABLE
OF LOW-TOPPED ROTATING STORMS OVER THE COASTAL PLAIN. ON THE HEELS
OF THE SURFACE LOW...A BROKEN LINE OF SHOWERS SHOULD DEVELOP ALONG
THE WEAK COLD FRONT AND CONVERGENCE ZONE...WHICH COULD STILL PRODUCE
SOME STRONG WIND GUSTS VIA DOWNWARD MOMENTUM TRANSPORT ON THE TAIL
END OF THE LOW LEVEL JET.
CATEGORICAL POPS DURING THE FIRST HALF OF THE DAY WILL TREND DOWN
QUICKLY FROM SOUTHWEST TO NORTHEAST AFTER 18Z AND THE CWA WILL BE
COMPLETELY DRY BY 00Z. HARD TO GET A SOLID HANDLE ON QPF AMOUNTS AS
PRECIP IS JUST NOW BEGINNING TO FILL IN ACROSS THE CWA. THE FOCI
FOR HEAVIER PRECIP WILL BE THE LLJ ENHANCED ISENTROPIC ACCENT OVER
THE CAD COLD DOME IN THE WEST AND ALSO THE SURFACE LOW/FRONTAL
PRECIP BAND OVER THE COASTAL PLAIN. HOURLY RAINFALL RATES UPSTREAM
ARE AROUND 0.10" TO 0.25"...WHICH AGREE WELL WITH THE RAP AND HRRR.
BASED ON THIS...A WIDESPREAD 1-1.5" STILL SEEMS REASONABLE.
REGARDING TEMPS...THE CWA WILL BE SPLIT BY THE INLAND PUSH OF THE
WARM SECTOR...WITH MID AND UPPER 40S OVER THE WESTERN PIEDMONT AND
UPPER 50S TO POSSIBLE MID 60S OVER THE COASTAL PLAIN. THERE IS A
CHANCE THAT WESTERLY WIND AND PARTIAL CLEARING BEHIND THE FRONT MAY
ALLOW TEMPS IN THE TRIAD TO JUMP A COUPLE EXTRA DEGREES BEFORE
SUNSET.
&&
.SHORT TERM /SUNDAY NIGHT THROUGH MONDAY NIGHT/...
AS OF 300 AM SUNDAY...
IN THE WAKE OF THE DEPARTING LOW PRESSURE SYSTEM...LOW LEVEL
MOISTURE WILL SLOWLY SCOUR VIA A WESTERLY WIND SUNDAY EVENING/NIGHT.
CIRRUS SHOULD SPREAD BACK IN FROM THE SOUTHWEST OVERNIGHT AND DURING
THE DAY MONDAY AHEAD OF A WAVE MOVING THROUGH THE MEAN UPPER TROUGH.
A WEAKENING MSLP GRADIENT AND AT LEAST PARTIAL CLEARING MAY LEAD TO
FOG POTENTIAL...THOUGH CONFIDENCE IN THIS IS LOW AT THE MOMENT.
LOWS 36-41. HIGHS MONDAY 49-56. -SMITH
MONDAY NIGHT:
THE PASSAGE OF THE MID/UPPER LEVEL TROUGH AND EMBEDDED
VIGOROUS SHORTWAVE WILL BRING AN INCREASE IN CLOUDS WITH SOME LIGHT
PRECIP DEVELOPING OVER THE AREA BETWEEN 06 TO 12Z TUESDAY IN
RESPONSE TO LOW AND MID-LEVEL FGEN UNDERNEATH RENEWED UPPER-LEVEL
DIVERGENCE WITHIN THE RIGHT ENTRANCE REGION OF A 150 JET CENTERED
OVER THE MID-ATLANTIC SEABOARD. THE GFS AND NAM EVEN SPIN UP A WEAK
SFC WAVE ALONG THE LINGERING FRONTAL BOUNDARY OFF THE NC COAST. THE
ECWMF WHICH HAD BEEN A DRY OUTLIER...HAS NOW JUMPED ON BOARD...WITH
AVERAGE QPF AMOUNTS OF 0.03 TO 0.06" ACROSS THE AREA.
FCST SOUNDINGS ARE MUCH WARMER IN THE BOUNDARY LAYER AND SATURATION
IS MUCH SHALLOWER...WITH NO SEEDING OF ICE FROM ABOVE GIVEN CLOUD
SEPARATION OF AROUND 10KFT. THUS HAVE REMOVED ANY MENTION OF SNOW
WITH JUST RAIN. LOWS IN THE MID 30S NW TO UPPER 30S/NEAR 40 SE.
&&
.LONG TERM /TUESDAY THROUGH SATURDAY/...
AS OF 300 AM SUNDAY...
TUESDAY AND WEDNESDAY:
UNDERNEATH ZONAL FLOW ALOFT...EXPECT DRY CONDITIONS WITH
TEMPERATURES AT OR JUST BELOW NORMAL AS THE MODIFIED CANADIAN HIGH
BUILDS EASTWARD OVER THE AREA.
THURSDAY THROUGH SATURDAY:
THERE REMAINS CONSIDERABLE UNCERTAINTY AND LARGE MODEL SPREAD AMONG
THE DETERMINISTIC MODEL GUIDANCE AND ENSEMBLES WITH RESPECT TO THE
UPSTREAM AMPLIFICATION/TIMING OF A NORTHERN STREAM WAVE DROPPING
SEWD THROUGH THE BASE OF THE MEAN TROUGH AND RESULTANT DOWNSTREAM
MILLER-B TYPE CYCLOGENESIS ALONG THE MID-ATLANTIC COAST. THE ECWMF
CONTINUES TO BE ON THE DEEPER/SLOWER SIDE OF GUIDANCE...BUT EVEN IT
HAS BACKED WITH PRECIP ACROSS THE AREA FOR WITH VERY LITTLE TO NO
SOUTHERN STREAM MOISTURE LINKAGE. MEANWHILE...THE QUICKER/MORE
PROGRESSIVE GFS REMAINS DRY. WILL HAVE TO CONTINUE MONITOR THIS
SYSTEM...PARTICULARLY THE TIMING AND JUST HOW CLOSE TO THE COAST THE
SYSTEM WILL DEVELOP. WILL KEEPS POPS IN THE SLGT CHC FOR THURSDAY
WITH FRIDAY DRY AS EVEN THE SLOWER EC HAS US DRY SLOTTED BY THEN.
OTHERWISE...TEMPS WILL GENERALLY BE NEAR OR SLIGHTLY BELOW NORMAL
THURSDAY DEPENDING ON PRECIP CHANCES...THEN WELL BELOW NORMAL BEHIND
THE SYSTEM ON FRIDAY AND INTO THE FIRST PART OF THE WEEKEND AS
ANOTHER ARCTIC HIGH BUILDS EASTWARD INTO THE REGION
&&
.AVIATION /06Z SUNDAY THROUGH THURSDAY/...
AS OF 1240 AM SUNDAY...
24 HOUR TAF PERIOD: AREAS OF LIGHT RAIN ARE SPREADING ACROSS CENTRAL
NC THIS MORNING AS A STORM SYSTEM BEGINS TO LIFT NORTHEAST FROM THE
GULF OF MEXICO. CEILINGS ARE MOSTLY MVFR AND VFR AT THE MOMENT BUT
WILL DROP RAPIDLY TO IFR AND LIFR BY 12Z AS MORE WIDESPREAD AND
HEAVIER RAIN OVERSPREADS THE AREA. AT THE SAME TIME...A
STRONG...SOUTHERLY LOW LEVEL JET OF AROUND 50KT WILL SURGE NORTH
ACROSS THE AREA...WHICH WILL LEAD TO A PERIOD OF LOW-LEVEL WIND
SHEAR THREAT DUE TO LIGHTER NORTHEASTERLY WINDS AT THE SURFACE. LOW-
LEVEL WIND SHEAR WILL BE MOST LIKELY BETWEEN 09Z AND
15Z...AFTERWHICH WINDS WILL START TO BECOME MORE UNIFORM OUT OF THE
SOUTHWEST AS THE STORM SYSTEM PULLS AWAY FROM THE AREA. GUSTY WINDS
WILL STILL BE POSSIBLE...ESPECIALLY IN THE EAST OF KRDU WHERE AN
ISOLATED THUNDER STORMS OR TWO IS POSSIBLE. PRECIP WILL COME TO AN
END FROM WEST TO EAST DUE THE AFTERNOON...WITH CEILINGS ALSO
SCATTERING AS WINDS BECOME MORE SOUTHWESTERLY.
LOOKING AHEAD: ANOTHER UPPER LEVEL DISTURBANCE WILL CROSS THE AREA
MONDAY NIGHT AND EARLY TUESDAY...POTENTIALLY GENERATING A FEW
SHOWERS AND A SHORT PERIOD OF SUB-VFR CEILINGS. FROM TUESDAY
AFTERNOON THROUGH EARLY THURSDAY EXPECT VFR CONDITIONS...WITH
ANOTHER POTENTIAL SHOT OF SOME RAIN THURSDAY AFT/EVE.
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...SMITH
NEAR TERM...SMITH
SHORT TERM...SMITH/CBL
LONG TERM...CBL
AVIATION...KC/SMITH
AREA FORECAST DISCUSSION
NWS RALEIGH NC
250 AM EST SUN DEC 29 2013
.SYNOPSIS...A LOW PRESSURE SYSTEM WILL TRACK ACROSS THE AREA
TODAY...FOLLOWED BY THE ATTENDANT COLD FRONT SUNDAY NIGHT. ANOTHER
UPPER LEVEL DISTURBANCE WILL CROSS THE REGION MONDAY NIGHT.
&&
.NEAR TERM /THROUGH TODAY/...
AS OF 250 AM SUNDAY...
AN UPPER LOW OVER THE LOWER MISSISSIPPI RIVER VALLEY WILL CONTINUE
TO LIFT NORTHEAST TODAY...DEAMPLIFYING AS IT BECOMES INCREASINGLY
NEGATIVELY TILTED. THE ASSOCIATED DCVA AND 50-60 LOW LEVEL JET WILL
DEEPEN AND ACCELERATE A SURFACE LOW...CURRENTLY DEVELOPING OVER THE
FLORIDA PANHANDLE...TOWARD THE DELMARVA AREA TODAY.
NOT A LOT OF CHANGES TO MAKE TO THE CURRENT FORECAST. AREAS OF
LIGHT RAIN OVER SPREADING THE AREA ARE CREATING AN IN-SITU COLD AIR
DAMMING AIRMASS AND STRENGTHENING THE STABILITY ACROSS THE CWA.
MODELS HAVE TRENDED A LITTLE EAST WITH THE TRACK OF THE SURFACE
LOW...ESPECIALLY THE GFS...THOUGH NOT AS MUCH AS ONE MIGHT EXPECT IF
THEY ARE CATCHING ONTO THE CAD AIRMASS. A CONSENSUS WOULD TRACK THE
LOW UP THE I-95 CORRIDOR BETWEEN 15Z AND 18Z. THE COASTAL WARM
FRONT AND 55-65F DEWPOINT AIR ALONG THE CAROLINA COAST WILL SURGE
INLAND AS PRESSURES BEGIN TO FALL...BUT IT APPEARS THE BETTER
MARITIME AIRMASS THAT WOULD LEAD TO BETTER DESTABILIZATION AND
SEVERE THREAT WILL STAY ALONG THE COAST...HINDERED BY THE STABLE CAD
AIRMASS. STILL..THERE MAY BE A BRIEF PERIOD (15-18Z) WHERE 250-500
J/KG OF NEAR SURFACE BASED CAPE CAN PHASE WITH HODOGRAPHS FAVORABLE
OF LOW-TOPPED ROTATING STORMS OVER THE COASTAL PLAIN. ON THE HEELS
OF THE SURFACE LOW...A BROKEN LINE OF SHOWERS SHOULD DEVELOP ALONG
THE WEAK COLD FRONT AND CONVERGENCE ZONE...WHICH COULD STILL PRODUCE
SOME STRONG WIND GUSTS VIA DOWNWARD MOMENTUM TRANSPORT ON THE TAIL
END OF THE LOW LEVEL JET.
CATEGORICAL POPS DURING THE FIRST HALF OF THE DAY WILL TREND DOWN
QUICKLY FROM SOUTHWEST TO NORTHEAST AFTER 18Z AND THE CWA WILL BE
COMPLETELY DRY BY 00Z. HARD TO GET A SOLID HANDLE ON QPF AMOUNTS AS
PRECIP IS JUST NOW BEGINNING TO FILL IN ACROSS THE CWA. THE FOCI
FOR HEAVIER PRECIP WILL BE THE LLJ ENHANCED ISENTROPIC ACCENT OVER
THE CAD COLD DOME IN THE WEST AND ALSO THE SURFACE LOW/FRONTAL
PRECIP BAND OVER THE COASTAL PLAIN. HOURLY RAINFALL RATES UPSTREAM
ARE AROUND 0.10" TO 0.25"...WHICH AGREE WELL WITH THE RAP AND HRRR.
BASED ON THIS...A WIDESPREAD 1-1.5" STILL SEEMS REASONABLE.
REGARDING TEMPS...THE CWA WILL BE SPLIT BY THE INLAND PUSH OF THE
WARM SECTOR...WITH MID AND UPPER 40S OVER THE WESTERN PIEDMONT AND
UPPER 50S TO POSSIBLE MID 60S OVER THE COASTAL PLAIN. THERE IS A
CHANCE THAT WESTERLY WIND AND PARTIAL CLEARING BEHIND THE FRONT MAY
ALLOW TEMPS IN THE TRIAD TO JUMP A COUPLE EXTRA DEGREES BEFORE
SUNSET.
&&
.SHORT TERM /SUNDAY NIGHT THROUGH TUESDAY NIGHT/...
AS OF 250 AM SUNDAY...
IN THE WAKE OF THE DEPARTING LOW PRESSURE SYSTEM...LOW LEVEL
MOISTURE WILL SLOWLY SCOUR VIA A WESTERLY WIND SUNDAY EVENING/NIGHT.
CIRRUS SHOULD SPREAD BACK IN FROM THE SOUTHWEST OVERNIGHT AND DURING
THE DAY MONDAY AHEAD OF A WAVE MOVING THROUGH THE MEAN UPPER TROUGH.
A WEAKENING MSLP GRADIENT AND AT LEAST PARTIAL CLEARING MAY LEAD TO
FOG POTENTIAL...THOUGH CONFIDENCE IN THIS IS LOW AT THE MOMENT.
LOWS 36-41. HIGHS MONDAY 49-56. -SMITH
TROUGH AXIS MOVES THROUGH EARLY TUESDAY... AND A SURFACE WAVE
DEVELOPS ALONG THE FRONT OFF THE COAST... BRINGING A PERIOD OF LIGHT
PRECIP EARLY TUESDAY IN THE GFS AND NAM RUNS IN ASSOCIATION WITH AN
AREA OF FRONTOGENETICAL FORCING. AS MENTIONED IN PREVIOUS
DISCUSSION... PARTIAL THICKNESSES POINT TO THE POTENTIAL FOR SOME
SNOW TO MIX IN BRIEFLY TOWARD THE END OF THE PRECIPITATION IN THE
PIEDMONT DURING THE MORNING HOURS TUESDAY... AS STRONG COLD
ADVECTION MOVES IN TO THE AREA. HIGH TEMPERATURES IN THE LOW 40S.
&&
.LONG TERM /WEDNESDAY THROUGH SATURDAY/...
AS OF 308 PM SATURDAY...
HIGH PRESSURE WILL BUILD IN TO THE SOUTHEAST ON WEDNESDAY.
SIGNIFICANT DIFFERENCES APPEARED IN PREVIOUS MODEL RUNS ON
THURSDAY... BUT MOST RECENT 12Z ECMWF RUN HAS COME CLOSER IN LINE
WITH THE GFS SOLUTION OF A STRONG WAVE DIGGING OVER THE OHIO VALLEY
ON THURSDAY. WILL CARRY SLIGHT CHANCE POPS FOR THE LATTER HALF OF
THURSDAY AT THIS POINT. HIGH PRESSURE WILL LIKELY BUILD IN BEHIND
THE DEPARTING SYSTEM ON SATURDAY. LOWS IN THE 20S TO LOW 30S WITH
HIGHS IN THE 40S DURING THIS PERIOD.
&&
.AVIATION /06Z SUNDAY THROUGH THURSDAY/...
AS OF 1240 AM SUNDAY...
24 HOUR TAF PERIOD: AREAS OF LIGHT RAIN ARE SPREADING ACROSS CENTRAL
NC THIS MORNING AS A STORM SYSTEM BEGINS TO LIFT NORTHEAST FROM THE
GULF OF MEXICO. CEILINGS ARE MOSTLY MVFR AND VFR AT THE MOMENT BUT
WILL DROP RAPIDLY TO IFR AND LIFR BY 12Z AS MORE WIDESPREAD AND
HEAVIER RAIN OVERSPREADS THE AREA. AT THE SAME TIME...A
STRONG...SOUTHERLY LOW LEVEL JET OF AROUND 50KT WILL SURGE NORTH
ACROSS THE AREA...WHICH WILL LEAD TO A PERIOD OF LOW-LEVEL WIND
SHEAR THREAT DUE TO LIGHTER NORTHEASTERLY WINDS AT THE SURFACE. LOW-
LEVEL WIND SHEAR WILL BE MOST LIKELY BETWEEN 09Z AND
15Z...AFTERWHICH WINDS WILL START TO BECOME MORE UNIFORM OUT OF THE
SOUTHWEST AS THE STORM SYSTEM PULLS AWAY FROM THE AREA. GUSTY WINDS
WILL STILL BE POSSIBLE...ESPECIALLY IN THE EAST OF KRDU WHERE AN
ISOLATED THUNDER STORMS OR TWO IS POSSIBLE. PRECIP WILL COME TO AN
END FROM WEST TO EAST DUE THE AFTERNOON...WITH CEILINGS ALSO
SCATTERING AS WINDS BECOME MORE SOUTHWESTERLY.
LOOKING AHEAD: ANOTHER UPPER LEVEL DISTURBANCE WILL CROSS THE AREA
MONDAY NIGHT AND EARLY TUESDAY...POTENTIALLY GENERATING A FEW
SHOWERS AND A SHORT PERIOD OF SUB-VFR CEILINGS. FROM TUESDAY
AFTERNOON THROUGH EARLY THURSDAY EXPECT VFR CONDITIONS...WITH
ANOTHER POTENTIAL SHOT OF SOME RAIN THURSDAY AFT/EVE.
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...SMITH
NEAR TERM...SMITH
SHORT TERM...SMITH/SEC
LONG TERM...SEC
AVIATION...KC/SMITH
AREA FORECAST DISCUSSION
NWS BISMARCK ND
142 AM CST SUN DEC 29 2013
.UPDATE...
ISSUED AT 142 AM CST SUN DEC 29 2013
MAIN UPDATES WITH THE EARLY MORNING FORECAST ISSUANCE WAS TO
ADJUST TEMPERATURES AND SKY COVER TRENDS.
1040 SURFACE HIGH WILL CONTINUE SOUTH INTO NORTH DAKOTA NOW
THROUGH 12Z...RESULTING IN CLEARING SKIES FROM NORTH TO SOUTH AND
DECREASING WINDS. AS THE SKIES CLEAR AND WIND
SUBSIDE...TEMPERATURES WILL RAPIDLY PLUMMET. EXPECT LOWS OF 20
BELOW TO NEAR 30 BELOW ZERO ACROSS PORTIONS OF CENTRAL NORTH
DAKOTA. WARMER SOUTHWEST AROUND 10 BELOW WHERE LINGERING CLOUDS
ARE FORECAST. TEMPERATURES WERE ADJUSTED BASED ON LATEST HR MODEL
DATA OF THE RAP AND HRRR.
NO CHANGES TO WIND CHILL HEADLINES.
UPDATE ISSUED AT 910 PM CST SAT DEC 28 2013
ALLOWED THE BLIZZARD WARNING TO EXPIRE OVER THE JAMES RIVER BASIN.
TEMPERATURES WILL CONTINUE TO PLUMMET AS AN ARCTIC AIR MASS BUILDS
INTO THE REGION.
OTHERWISE...THE LATEST RAP AND UPSTREAM OBS INDICATE SCATTERED
FLURRIES DEVELOPING OVER WESTERN NORTH DAKOTA AFTER MIDNIGHT.
AFTER COLLABORATING WITH THE MONTANA OFFICES AND RAPID
CITY...DECIDED TO ADD FLURRIES OVER WESTERN NORTH DAKOTA.
OTHERWISE...THE REMAINING FORECAST ELEMENTS ARE IN GOOD SHAPE. THE
UPDATED GRIDDED AND TEXT PRODUCTS HAVE BEEN SENT.
UPDATE ISSUED AT 719 PM CST SAT DEC 28 2013
SENT OUT AN UPDATE TO ALLOW THE BLIZZARD WARNING TO EXPIRE ACROSS
THE NORTHEASTERN CWA THIS EVENING. HOWEVER...MAINTAINED THE
BLIZZARD WARNING FOR THE SOUTHERN JAMES RIVER BASIN FOR THE NEXT
FEW HOURS AS WINDS CONTINUE TO GUST UP TO 40 MPH GENERATING
BLOWING SNOW.
THE UPDATED PRODUCTS HAVE BEEN SENT.
UPDATE ISSUED AT 520 PM CST SAT DEC 28 2013
UPDATED THE FORECAST TO CANCEL THE BLIZZARD WARNING FOR AREAS
ALONG AND WEST OF HIGHWAY 83 ACROSS NORTHWESTERN NORTH DAKOTA.
WINDS CONTINUE TO COME DOWN AND VISIBILITIES CONTINUE TO IMPROVE.
HOWEVER...ACROSS THE EASTERN CWA...BLIZZARD CONDITIONS CONTINUE TO
BE REPORTED...ESPECIALLY ACROSS THE JAMES RIVER BASIN. WILL KEEP
THE BLIZZARD WARNING IN EFFECT THROUGH EARLY EVENING THERE AS A RESULT.
IN ADDITION...EXPANDED THE AREAL COVERAGE OF THE WIND CHILL
WARNING BASED ON LATEST OBS/TRENDS. THE UPDATED PRODUCTS HAVE BEEN
SENT.
&&
.SHORT TERM...(THIS EVENING THROUGH SUNDAY)
ISSUED AT 311 PM CST SAT DEC 28 2013
MAIN CONCERNS ARE WINTER HEADLINES AND DANGEROUS WIND CHILLS AS
ARCTIC AIR CONTINUES TO OVERSPREAD THE STATE. LOW PRESSURE CENTER
HAS MOVED TO SOUTHERN MINNESOTA WITH STRONG NORTHWEST WINDS
CONTINUING ACROSS OUR REGION.
BLIZZARD WARNING REMAINS IN EFFECT FOR MUCH OF NORTHERN CWA INTO
THE JAMES RIVER VALLEY INTO THE EARLY EVENING. CONDITIONS ARE
BEGINNING TO IMPROVE ACROSS THE NORTHWEST AND EXPECTED TO
DETERIORATE SOUTHEAST INTO THIS EVENING AS BAND OF LIGHT SNOW
SPREADS ACROSS THAT AREA WITH VERY STRONG WINDS CONTINUING.
BLIZZARD WARNING ENDS AT 01Z EVERYWHERE EXCEPT FAR SOUTHEAST WHICH
CONTINUES UNTIL 3Z...WHEN CONDITIONS SHOULD IMPROVE.
WIND CHILLS AT 21Z RANGED FROM 20 TO 30 BELOW ZERO ACROSS THE NORTH
AND THE NEGATIVE TEENS SOUTH. ENTIRE AREA IS COVERED BY WIND CHILL
ADVISORY WITH A WIND CHILL WARNING REMAINING IN PLACE ACROSS THE
NORTHEAST WITH WIND CHILLS TO 45 BELOW EXPECTED TONIGHT. MODELS IN
GOOD AGREEMENT WITH HIGH PRESSURE BUILDING IN ACROSS THE STATE
OVERNIGHT ALONG WITH DIMINISHING WINDS AND CLEARING SKIES. RETURN
FLOW SETS UP BY SUNDAY AFTERNOON ACROSS THE WEST AS HIGH PRESSURE
CONTINUES TO SLIDES OVER EASTERN SOUTH DAKOTA WITH INCREASING
CLOUDS AND SOME MODERATION IN TEMPERATURES REACHING SINGLE DIGITS
ABOVE ZERO WEST AND BELOW ZERO ELSEWHERE.
.LONG TERM...(SUNDAY NIGHT THROUGH SATURDAY)
ISSUED AT 311 PM CST SAT DEC 28 2013
THE HIGHLIGHTS OF THE EXTENDED FORECAST ARE DANGEROUS WIND CHILLS
FOR MUCH OF THE AREA SUNDAY THROUGH TUESDAY NIGHTS...AND
ACCUMULATING SNOW TUESDAY.
THE 12 UTC CONSENSUS IS IN AGREEMENT ON THE THE BOUNDARY OF THE
ARCTIC AIRMASS TO REMAIN ACROSS EASTERN MONTANA INTO SOUTHWEST
NORTH DAKOTA SUNDAY NIGHT THROUGH WEDNESDAY. THUS...DANGEROUS
NIGHTTIME AND EARLY MORNING WIND CHILLS SHOULD CONTINUE ACROSS
MUCH OF NORTHERN AND CENTRAL NORTH DAKOTA SUNDAY THROUGH WEDNESDAY
NIGHTS...WITH THE RELATIVELY WARMER SOUTHWEST FORECAST AT THIS
TIME TO REMAIN ABOVE ADVISORY CRITERIA.
IN REGARDS TO PRECIPITATION...A WAVE COMING ONSHORE TO BRITISH
COLUMBIA MONDAY IS FORECAST TO PROPAGATE SOUTHEAST AND INTERACT
WITH THE LOW LEVEL BAROCLINIC ZONE ON TUESDAY. AS A RESULT...A
BAND OF LIGHT TO MODERATE ACCUMULATING SNOW MAY BE POSSIBLE ACROSS
THE WEST AND FAR SOUTH CENTRAL. ADVISORY LEVEL SNOWFALL
ACCUMULATIONS MAY BE POSSIBLE...HOWEVER...WINDS ARE EXPECTED TO BE
LIGHT.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT)
ISSUED AT 142 AM CST SUN DEC 29 2013
BKN-OVC MID LEVEL CLOUDS WILL SLOWLY CLEAR NOW THROUGH 12-15Z AS
SURFACE HIGH PRESSURE BUILDS ACROSS NORTH DAKOTA. VFR FLIGHT
CONDITIONS EXPECTED THROUGH SUNDAY AFTERNOON. ANOTHER CLIPPER
STORM SYSTEM WILL MOVE SOUTHEAST INTO THE DAKOTAS SUNDAY EVENING
OVERNIGHT INTO MONDAY MORNING. EXPECT TO SEE DETERIORATING FLIGHT
CONDITIONS WEST SUNDAY EVENING IMPACTING KISN AND KDIK...THEN
EASTWARD LATER SUNDAY NIGHT IMPACTING KBIS-KMOT-KJMS. CIGS ARE
FORECAST TO DROP TO MVFR AND VIS IN FALLING SNOW FALLING TO IFR
AND POSSIBLY LOWER.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
WIND CHILL ADVISORY UNTIL 1 PM CST /NOON MST/ THIS AFTERNOON FOR
NDZ001-009-010-017>021-031>035-040>046.
WIND CHILL WARNING UNTIL 1 PM CST THIS AFTERNOON FOR NDZ002>005-
011>013-022-023-025-036-037-047-048-050-051.
&&
$$
UPDATE...NH
SHORT TERM...JNS
LONG TERM...AYD
AVIATION...NH
AREA FORECAST DISCUSSION
NWS CHARLESTON WV
336 AM EST SUN DEC 29 2013
.SYNOPSIS...
LOW PRESSURE MOVES UP THE EAST COAST TODAY. COLD FRONT LATE SUNDAY
NIGHT INTO MONDAY. HIGH PRESSURE TUESDAY. ANOTHER SYSTEM THURSDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
EXTENSIVE SHIELD OF RAIN HAS NOW OVERSPREAD THE AREA...AND SHOULD
CONTINUE TO ENCOMPASS MOST COUNTIES THROUGH 12Z TODAY. SURFACE LOW
PRESSURE BRINGING THE MOISTURE INTO THE CWA WILL RACE UP THE EAST
COAST. WILL START LOSING THE DEPTH OF THIS MOISTURE AFTER 18Z
TODAY...AND WILL REDUCE THE POPS ACCORDINGLY AS THE UPPER AND MID
LEVELS ACQUIRE DRIER AIR. STILL EXPECTING TOTALS TO TOP OUT IN THE 1
TO 1.25 INCH RANGE...LIKELY OVER SOUTHWEST VIRGINIA AND THE SOUTHERN
MOUNTAINS.
TIMING IS STILL IN GOOD AGREEMENT AMONGST THE MODELS...BUT HAVE
FOCUSED ON THE HIGH RESOLUTION HRRR AND WRF MODELS FOR THE TIMING IN
TERMS OF DECREASING THE POPS THROUGH THE AFTERNOON AND EVENING.
MEANWHILE...A COLD FRONT CURRENTLY PLOWING THROUGH THE NORTHERN
PLAINS USHERING A BITTERLY COLD ARCTIC AIRMASS. THIS COLD FRONT WILL
RAPIDLY PUSH THROUGH THE SOUTHERN GREAT LAKES...AND WILL REACH OUR
SOUTHEAST OHIO COUNTIES AFTER 00Z MONDAY. IT WILL NOT BE BRINGING
QUITE THE SAME AIR CURRENTLY FILLING IN BEHIND THE FRONT IN
MINNESOTA AND THE DAKOTAS...BUT IT WILL BE A SIGNIFICANT AIRMASS
CHANGE FOR THE MIDDLE OHIO VALLEY. CAN EXPECT A FEW SNOW SHOWERS
WITH THE FRONT...AND THEN NORTHWESTERLY FLOW IN PLUNGING 850MB
TEMPERATURE AIR BRINGING UPSLOPING SNOW CONDITIONS THAT WILL EXTEND
INTO THE SHORT TERM FORECAST PERIOD.
NOT EXPECTING MUCH IN TERMS OF TEMPERATURE RECOVERY TODAY IN THE
RAIN...WITH UPPER 30S TO LOWER 40S EXPECTED. BEHIND THE COLD
FRONT...LOW 20S WILL FIND THEIR WAY INTO THE SOUTHEAST OHIO COUNTIES
BY 12Z MONDAY.
&&
.SHORT TERM /MONDAY THROUGH THURSDAY NIGHT/...
THIS PERIOD WILL BE CHARACTERIZED BY FAST WEST TO NORTHWEST FLOW
ALOFT...WITH A DIGGING NORTHERN STREAM UPPER TROUGH OVER THE
MISSISSIPPI AND OHIO VALLEYS BY THURSDAY. OPERATIONAL MODELS ARE
STRONGLY TRENDING TOWARD THIS SCENARIO. IN THIS FAST FLOW...POST
COLD FRONTAL SNOW SHOWERS...MAINLY IN THE NORTHERN AND CENTRAL
MOUNTAINS...MOVE OUT QUICKLY MONDAY AFTERNOON...AS HIGH PRESSURE
BUILDS IN RAPIDLY FROM THE WEST AND ENDS THE COLD ADVECTION. WITH
NOT MUCH OF AN UPSLOPE EVENT AND MOISTURE RATHER SHALLOW...EXPECT
ONLY AN INCH OR TWO IN THE HIGHER ELEVATIONS BEFORE ENDING MONDAY
AFTERNOON. TEMPERATURES WILL BE BELOW NORMAL WITH MONDAY HIGHS
STRUGGLING TO REACH ABOVE FREEZING...EVEN WITH INCREASING SUNSHINE.
TUESDAY AND WEDNESDAY WILL SEE CLIPPER LIKE SYSTEMS TRACKING JUST TO
OUR NORTH...WITH THE MAIN EFFECT BEING SOME CLOUDS ACROSS THE NORTH
HALF OF THE AREA. PRECIP...HOWEVER...SHOULD ALSO STAY JUST NORTH
WHERE ALONG THE CLIPPER TRACK. TEMPERATURES WILL BE ON A SLOW RISE
TUESDAY AND WEDNESDAY WITH A WEAK SOUTHERLY FLOW...WITH HIGHS
REACHING TO NEAR NORMAL READINGS BY WEDNESDAY.
THE NEXT SIGNIFICANT LOW PRESSURE SYSTEM AND COLD FRONT FOR THURSDAY
WILL BE A REFLECTION OF THE DIGGING UPPER TROUGH. FORECAST
AMPLIFICATION OF THE UPPER TROUGH SUGGESTS THE TRACK OF THE SURFACE
LOW WILL BE CLOSE TO OUR AREA. THIS WILL PUT US ON THE EDGE OF
WINTRY VERSUS LIQUID PRECIP. FOR NOW...WILL KEEP A WINTRY MIX
THURSDAY AND THEN SNOW SHOWERS THURSDAY NIGHT BEHIND THE COLD FRONT.
BUT WOULD NOT BE SURPRISED TO SEE A NORTHWARD SHIFT OF THE SURFACE
LOW AND WARMER SCENARIO AHEAD OF THE COLD FRONT ON FUTURE MODEL
RUNS.
&&
.LONG TERM /FRIDAY THROUGH SATURDAY/...
LOW PRESSURE AND SNOW SHOWERS MOVE OUT FRIDAY. SNOW ACCUMULATIONS
ARE ANTICIPATED...ESPECIALLY OVER THE NORTHEAST MOUNTAINS BY EARLY
FRIDAY.
WPC CONTINUES HONORING THE ECMWF SOLUTION IN THE EXTENDED FORECAST.
BLENDED WPC AND GMOS FOR WINDS AND TEMPERATURES THROUGH THE PERIOD
DUE TO LOWER CONFIDENCE BEYOND DAY 4. TEMPERATURES WILL DEPEND ON
THE TRAJECTORIES OF THE AFOREMENTIONED SHORTWAVES AS THEY WILL
REINFORCE THE COLD AIR BEHIND ANY SFC REFLECTION...AND BRING PLENTY
OF CLOUDINESS.
&&
.AVIATION /09Z SUNDAY THROUGH THURSDAY/...
EXPECT CONDITIONS AT ALL TERMINALS TO GO DOWNHILL OVER THE NEXT
FEW HOURS AS THE RAIN SETTLES IN. EXPECT IFR OR POSSIBLY
WORSE...TO LIFR BY MORNING FOR MOST LOCATIONS AS THE LOW PRESSURE
SYSTEM MOVES UP THE ATLANTIC COAST. ANY BREAKS IN THE RAIN THROUGH
15Z SUNDAY WILL POSSIBLY RESULT IN THE LIFR CONDITIONS.
AS THE SYSTEM LIFTS TO THE NORTHEAST...MID AND UPPER LEVEL
MOISTURE WILL GRADUALLY EXIT...TAKING THE RAIN WITH IT BY 00Z
MONDAY. CEILINGS WILL IMPROVE TO MVFR AS WILL
VISIBILITIES...POSSIBLY REACHING VFR...AS WEST WINDS INCREASE TO
10KTS...STIRRING UP THE LOWEST LEVELS OF THE ATMOSPHERE.
FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 06Z MONDAY...
FORECAST CONFIDENCE: MEDIUM.
ALTERNATE SCENARIOS: TEMPOS FOR OSCILLATIONS BETWEEN IFR AND LIFR
MAY BE NEEDED THROUGH 15Z. AMENDMENTS POSSIBLE FOR THIS.
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 SUN 12/29/13
UTC 1HRLY 08 09 10 11 12 13 14 15 16 17 18 19
EST 1HRLY 03 04 05 06 07 08 09 10 11 12 13 14
CRW CONSISTENCY H H H M H H H H H H H H
HTS CONSISTENCY H H H H H H H H H H H H
BKW CONSISTENCY M L L H H M M M H M M H
EKN CONSISTENCY M M L L L L M H H H H H
PKB CONSISTENCY H H M H M L H H H H H H
CKB CONSISTENCY H H H H M M M M H H H H
AFTER 06Z MONDAY...
IFR POSSIBLE IN SNOW SHOWERS AFTER 06Z MONDAY.
&&
.RLX WATCHES/WARNINGS/ADVISORIES...
WV...NONE.
OH...NONE.
KY...NONE.
VA...NONE.
&&
$$
SYNOPSIS...JMV/26
NEAR TERM...26
SHORT TERM...JMV
LONG TERM...JMV/ARJ
AVIATION...26
AREA FORECAST DISCUSSION
NWS WILMINGTON OH
1247 AM EST SUN DEC 29 2013
.SYNOPSIS...
RAIN WILL OCCUR WELL NORTH AND WEST OF A LOW PRESSURE SYSTEM THAT
WILL TRACK FROM THE GULF COAST INTO THE MID ATLANTIC TONIGHT INTO
TOMORROW. A COLD FRONT MOVING IN FROM THE NORTHWEST WILL QUICKLY
FOLLOW LATE SUNDAY INTO SUNDAY EVENING. HIGH PRESSURE WILL BUILD
IN MONDAY.
&&
.NEAR TERM /UNTIL 6 AM THIS MORNING/...
SHIELD OF RAIN CONTINUES TO ADVANCE NORTH NORTHEAST ACROSS
KENTUCKY. THE WESTERN EDGE OF THIS LOOKS RAGGED BUT SOME LIGHT
PRECIPITATION IS STILL LIKELY REACHING THE GROUND THERE. LATEST
HRRR AND RAP RUNS HAVE COME INTO PRETTY GOOD AGREEMENT IN
SPREADING THE RAIN ACROSS MOST OF THE FORECAST AREA LATE TONIGHT
INTO SUNDAY MORNING. PROBABLY WILL NOT BE A STEADY RAIN
PARTICULARLY IN THE WESTERN AND NORTHERN AREAS BUT CHANCE OF
MEASURABLE PRECIPITATION CERTAINLY LOOKS HIGHER. THUS POPS HAVE
BEEN NUDGED UPWARD AGAIN.
TEMPERATURES WERE ADJUSTED TO ACCOUNT FOR RECENT OBSERVATIONAL
TRENDS WITH OUTLYING AREAS DROPPING A BIT FASTER THIS EVENING
DESPITE EXTENSIVE HIGH CLOUDS. EXPECT ONCE RAIN AND INCREASED LOW
LEVEL MOISTURE ARRIVE LATER TONIGHT THAT READINGS WILL LEVEL OUT
AND PERHAPS INCREASE A DEGREE OR TWO IN SOME PLACES.
&&
.SHORT TERM /6 AM THIS MORNING THROUGH MONDAY NIGHT/...
CUT DOWN ON THE HIGH TEMPERATURES SUNDAY WHERE RAIN WOULD BE
STARTING THE DAY BUT THIS WAS ONLY ABOUT 2 DEGREES. NORTHERN AND
NORTHWEST TEMPS WERE LOOKING GOOD IN THE LOWER 40S.
RAIN WILL EXIT DURING THE MORNING AND A LULL IN PRECIPITATION IS
CALLED FOR IN THE EARLY AFTERNOON. UPPER LEVEL SHORTWAVE IS
HELPING SHUNT THE WESTERN EDGE OF THE PRECIPITATION ALONG QUICKLY
IN THE EARLY AFTERNOON. WHILE NOT A TYPICAL FIELD USED FOR
TIMING...THE H7 OMEGA IS SHOWING A PRONOUNCED MINIMA AT 15 AND 18Z
WHICH SHOULD INDICATE THE BACK EDGE OF THE RAINFALL.
ONCE COLDER AIR IS USHERED IN LATER IN THE DAY...LOOK FOR THE WIND
SHIFT TO NORTHWEST...ANY LINGERING MOISTURE WILL BE WRUNG OUT BY
THE FALLING TEMPERATURES THROUGH THE ATMOSPHERE AND A QUICK
TRANSITION TO SCATTERED SNOW SHOWERS APPEARS TO BE IN THE OFFING.
ANY OF THESE SNOW SHOWERS SHOULD BE LIGHT AND NOT A PROBLEM IN AND
OF THEMSELVES...LINGERING THROUGH ABOUT MIDNIGHT AND THEN TURNING
OFF AS THE AIRMASS DRIES SIGNIFICANTLY.
HIGH PRESSURE WILL BUILD OVER THE MIDWEST SUNDAY NIGHT AND MONDAY
AND CONTINUE TO FILTER IN COLDER AND DRIER AIR FOR ANOTHER TASTE
OF WINTER TO THE OHIO VALLEY FOR THE EARLY PART OF THE WEEK.
&&
.LONG TERM /TUESDAY THROUGH SATURDAY/...
EXTENDED MODELS HAVE CONVERGED WITH THEIR SOLUTIONS...BUT THERE
REMAINS SOME DIFFERENCES WITH THE DETAILS.
PERIOD BEGINS WITH A SYSTEM PASSING NORTH OF THE REGION THROUGH THE
GREAT LAKES. IT LOOKS LIKE THE PCPN SHOULD STAY TO THE N...WITH ONLY
SOME CLOUDS. MODELS THEN DROP SOME H5 ENERGY INTO THE ERN U.S. TROF
TUESDAY NIGHT. AN AREA OF ISENTROPIC LIFT ASSOCIATED WITH A WEAK
LOW/SFC TROF SWINGS ACROSS THE REGION TUESDAY NIGHT INTO WEDNESDAY.
THIS LIFT CAUSES AN AREA OF SNOW..MAINLY ACROSS THE NRN HALF OF THE
FA.
ON THURSDAY...THE MODELS PHASE SOME SRN AND NRN STREAM ENERGY ACROSS
THE ERN U.S. WHILE THE GFS/ECMWF AND CMC HEMISPHERIC ALL HAVE A
SYSTEM THAT AFFECTS THE AREA ON THURSDAY...THE STRENGTH OF THE
SYSTEM VARIES. WENT WITH A 12Z GFS/00Z ECMWF BLEND. THIS SPREADS
SNOW ACROSS MOST OF THE REGION WITH SOME RAIN/SNOW IN THE SE. HIGH
PRESSURE BUILDS IN FOR FRIDAY INTO SATURDAY.
WARMED UP HIGHS ON TUESDAY TO THE UPPER 20S IN WEST CENTRAL OHIO TO
THE MID 30S IN NRN KY. WITH THE WEAK CLIPPER TYPE SYSTEM ON
WEDNESDAY HIGHS WILL BE HELD DOWN INTO THE MID 20S TO LOWER 30S.
HIGHS WILL REMAIN ABOUT THE SAME THURSDAY INTO FRIDAY BEFORE WARMING
A FEW DEGREES SATURDAY. LOWS WILL TYPICALLY BE IN THE TEENS TO LOW
20S.
&&
.AVIATION /06Z SUNDAY THROUGH THURSDAY/...
RAIN WILL SPREAD NORTHWARD ACROSS THE AREA TONIGHT ASSOCIATED WITH
LOW PRESSURE LIFTING NORTHEAST ACROSS THE CAROLINAS. THIS
PRECIPITATION WILL BRING WITH IT OCCASIONAL MVFR VSBYS OVERNIGHT
AND INTO THE EARLY PARTS OF THE DAY SUNDAY. AS THE PRECIPITATION
SPREADS ACROSS THE AREA...OVERNIGHT LOW LEVEL COOLING COMBINED WITH
MOISTENING DUE TO RAINFALL WILL CAUSE CIGS TO LOWER TO IFR LATE
TONIGHT. AS THE RAIN LIFTS NORTHEAST OF THE AREA LATER SUNDAY
MORNING...CIGS ARE EXPECTED TO IMPROVE TO MVFR. COLD ADVECTION
WILL INTENSIFY DURING THE EARLY EVENING AS HIGH PRESSURE BEGINS TO
BUILD INTO THE REGION FROM THE WEST. THIS WILL PRODUCE WEST TO
NORTHWESTERLY WINDS THAT WILL LIKELY GUST UP TO 25 KT THROUGH THE
EVENING. THIS COLD ADVECTION WILL ALSO HELP TO PRODUCE SCATTERED
SNOW SHOWERS IN THE AREA. IT ALSO APPEARS THAT CIGS WILL LOWER
BACK TO IFR DURING THE EVENING AS SNOW SHOWERS DEVELOP.
OUTLOOK...MVFR CEILINGS POSSIBLE WEDNESDAY AFTERNOON INTO
THURSDAY. MVFR TO IFR VISIBILITIES POSSIBLE THURSDAY.
&&
.ILN WATCHES/WARNINGS/ADVISORIES...
OH...NONE.
KY...NONE.
IN...NONE.
&&
$$
SYNOPSIS...
NEAR TERM...
SHORT TERM...FRANKS
LONG TERM...SITES
AVIATION...LATTO
AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NWS RAPID CITY SD
935 PM MST SAT DEC 28 2013
.UPDATE...
ISSUED AT 800 PM MST SAT DEC 28 2013
AFTERNOON RAP AS WELL AS LATEST RAP MODEL HAD FLURRIES COMING
DOWN FROM ND/MT AS WEAK SHORTWAVE DROPS INTO THE NORTHERN PLAINS.
LATEST RADAR/OBSERVATIONAL TRENDS SUPPORT...SO WILL HAVE FLURRIES
GOING OVER ENTIRE CWA ENTIRE NIGHT.
UPDATE ISSUED AT 557 PM MST SAT DEC 28 2013
LATEST RADAR TRENDS AS WELL AS SURFACE OBSERVATIONS SHOWED
-SN/--SN POPPING UP AS ARCTIC AIR SETTLES INTO THE CWA. WILL
INTRODUCE LOW POPS/FLURRIES TO SOUTHWEST 2/3RDS OF AREA FOR THIS
EVENING.
&&
.SHORT TERM...THIS EVENING THROUGH SUNDAY NIGHT
ISSUED AT 225 PM MST SAT DEC 28 2013
THE ARCTIC FRONT HAS ARRIVED FORCEFULLY AS HIGH WIND WARNING
CRITERIA HAVE BEEN MET ACROSS NWRN INTO WCNTRL SD AND 24-HR
TEMPERATURE DROPS OF -20 TO -40F ARE COMMON ACROSS THE CWA.
SNOWFALL HAS BEEN MINIMAL...AND CONFINED MOSTLY TO NERN WY AND FAR
NWRN SD AS CONFIRMED BY WEBCAMS AND SFC/RADAR OBS.
THE LATEST WATER VAPOR IMAGES SHOW THE UPPER TROUGH AXIS NEARING THE
NWRN CWA...AND RADAR IMAGES SHOW A FEW BANDS OF SNOW MOVING ACROSS
WCNTRL SD. THE STRONG SFC PRESSURE RISES OF 6-8 MB/3HR WERE CENTERED
OVER SCNTRL ND AND MOVING SOUTHEAST. THESE RISES ALSO HAVE BEEN
WEAKENING WITH TIME (MORESO THAN EXPECTED TO OCCUR WITH THE SEMI-
DIURNAL TIDE)...THUS THE WIND SPEEDS SHOULD TREND DOWNWARD OVER THE
NEXT SEVERAL HOURS. THE COLD ADVECTION STILL WAS QUITE STRONG ACROSS
THE CWA...AND WILL CONTINUE TO BE SO THROUGH THE EARLY EVENING. THIS
SUPPORTS THE WIND CHILL ADVY THAT IS IN EFFECT FOR NWRN SD TONIGHT.
ON THE LARGER-SCALE...THE SHORT-WAVE TROUGH WILL MOVE EAST OF THE
CWA OVERNIGHT AS ANOTHER ONE DROPS SOUTH ACROSS ND BY 12Z SUNDAY. A
SURFACE HIGH WILL BUILD OVER THE DAKOTAS...HELPING TO LESSEN THE
WINDS...BUT ALSO CONTINUING TO USHER COLD AIR INTO THE REGION. SNOW
SHOULD END FAIRLY QUICKLY THIS EVENING AS THE FORCING IS WEAK AND
MOISTURE IS MINIMAL. THE 850-MB TEMPS ALSO MAY RISE A FEW DEGREES BY
12Z AS THE COLDEST POCKET OF AIR IS PROGGED TO BE JUST SOUTHEAST OF
THE CWA.
ON SUNDAY A LEE TROF WILL DEVELOP OVER ERN WY IN RESPONSE TO THE
NEXT APPROACHING SHORT-WAVE TROUGH THAT WILL REACH ERN MT AND WY BY
24Z. THE RESULT WILL BE LOW-LEVEL WARM ADVECTION ACROSS MUCH OF THE
CWA AS THE TIGHT BAROCLINIC ZONE SHIFTS EASTWARD. A LACK OF MIXING
WILL PREVENT THIS WARM AIR FROM AFFECTING SURFACE TEMPERATURES OVER
THE ERN HALF OF THE CWA.
ON SUNDAY NIGHT THERE SHOULD BE A SLUG OF MIDLEVEL MOISTURE AS ONE
SHORT-WAVE TROUGH PASSES OVER THE CWA AND ANOTHER ONE FOLLOWS
QUICKLY BEHIND THE FIRST. THE SURFACE TROUGH WILL MOVE EAST AS
WELL...ENGENDERING MIXING AND STEADY/RISING TEMPERATURES OVERNIGHT.
SOME UPSLOPE SNOW APPEARS LIKELY...ALTHOUGH LOW-LEVEL MOISTURE WILL
LIMIT THE CHANCE OF SNOW ACROSS THE PLAINS.
&&
.LONG TERM...MONDAY THROUGH SATURDAY
ISSUED AT 225 PM MST SAT DEC 28 2013
ACTIVE NW FLOW THROUGH THE MIDDLE OF THE WEEK...WITH SEVERAL
SHORT-WAVE TROUGHS EXPECTED TO ADVECT SE ACROSS THE NORTHERN
PLAINS. POSITIVE HEIGHT ANOMALY OVER THE EASTERN PAC WILL
PERSIST...WITH RIDGE-TOPPING IMPULSES SQUELCHING THE RIDGE
AMPLITUDE AT TIMES. THE STRENGTH OF THE WESTERN CONUS RIDGE WILL
DICTATE THE LOCATION OF THE WAVERING FRONTAL BOUNDARY ACROSS THE
REGION...WITH THIS FEATURE LIKELY TO REMAIN GENERALLY ACROSS THE
FA THROUGH THE MIDDLE OF NEXT WEEK. WESTERN AREAS WILL TEND TO BE
AT OR ABOVE SEASONAL NORMS...WITH EASTERN AREAS REMAINING BELOW
NORMAL. DETERMINISTIC AND ENSEMBLE SOLUTIONS ARE SUPPORTING
ANOTHER RESURGENCE OF THE WESTERN CONUS RIDGE BY WED OF NEXT WEEK
AS THE SE CANADIAN NEGATIVE HEIGHT ANOMALY SHIFTS RAPIDLY EAST
GIVEN A STRONG ASSOCIATED NORTHERN-ATLANTIC UPPER JET. THIS WILL
ALLOW WARMER AIR TO SHIFT BACK EAST OFF THE ROCKIES AND INTO THE
NORTHERN PLAINS...UNTIL THE NEXT BUBBLE OF ARCTIC AIR ADVANCES
SOUTH TOWARD THE REGION THE FOLLOWING WEEKEND...BEING AIDED BY
ANOTHER POWERFUL NORTHERN PAC UPPER TROUGH...WITH THE CENTRAL
CANADIAN NEGATIVE HEIGHT ANOMALY DRIVING MOST OF THE PATTERN ONCE
AGAIN. THERE ARE GROWING INDICATIONS IN THE ECMWF FOR AN EASTWARD
EXTENSION OF THE EAST-ASIAN UPPER JET...WHICH WOULD SUPPORT
SUBSTANTIAL HEIGHT RISES OVER THE EASTERN PAC...AND A STRONGLY
POSITIVE PNA. A STRONG LEADING UPPER TROUGH WOULD BE POSSIBLE WITH
THIS TRANSITION...POSSIBLY SUPPORTING A WINTER STORM FOR THE
REGION. THIS IS HINTED AT IN THE LATEST SUCCESSIVE RUNS OF THE
ECMWF VALID FOR THE END OF NEXT WEEKEND.
MON-WED...SEVERAL NW FLOW IMPULSES EXPECTED...OF WHICH TIMING/
STRENGTH/AND TRACK VARIABILITY REMAINS. HAVE RETAINED LOW TO MID
RANGE POPS THROUGH MOST PERIODS FOR THESE DISTURBANCES...WITH NW
AREAS CONTINUING TO SEE THE BEST CHANCE FOR ANY SNOW ACCUMS...ESP
THE NORTHERN BLACK HILLS. THE MOST PERSISTENT AND STRONGEST
IMPULSE LOOKS TO REMAIN IN THE TUE PERIOD...THUS A POP RAISE WAS
WARRANTED. THE TEMP RANGE ACROSS THE FA WILL REMAIN QUITE LARGE
FROM WEST TO EAST...WITH EASTERN AREAS STRUGGLING TO SCOUR OUT THE
LL COLD AIR MASS.
THUR-SAT...WESTERN CONUS RIDGE WILL SHIFT EAST WITH A WARMER PATTERN
EXPECTED FOR THE FA...AS WESTERLY DOWNSLOPE FLOW PREVAILS. THIS WILL
SUPPORT DRY WEATHER...WITH TEMPS WARMING INTO THE 30S AND 40S WITH
SOME 50S CERTAINLY POSSIBLE IN THE LEE OF THE BLACK HILLS. THE RIDGE
WILL SHIFT EAST SAT...WITH A STRONG UPPER IMPULSE EXPECTED INTO THE
WESTERN CONUS. THIS SUPPORTS LOW POPS SAT ATTM. THE POTENTIAL FOR A
WINTER STORM REMAINS FOR SAT-SUN...GIVEN THE PATTERN SHIFT AND
STRONG LL BAROCLINIC ZONE EXPECTED. THIS WILL BEAR WATCHING.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT)
ISSUED AT 931 PM MST SAT DEC 28 2013
AREAS MVFR CIGS WILL SLOWLY SHIFT SOUTH OF AREA OVERNIGHT LEAVING
VFR CONDITIONS/MID-CLOUDS WITH A FEW --SN. VFR CONDITIONS EXPECTED
SUNDAY WITH MID/HIGH CLOUDS...ALTHOUGH SOME MVFR CIGS WILL MOVE
ACROSS FAR NORTHWEST SD THROUGHOUT SUNDAY.
&&
.UNR WATCHES/WARNINGS/ADVISORIES...
SD...WIND CHILL ADVISORY UNTIL 10 AM MST SUNDAY FOR SDZ001-002-
012>014-032-073.
WY...NONE.
&&
$$
UPDATE...HELGESON
SHORT TERM...BUNKERS
LONG TERM...JC
AVIATION...HELGESON
AREA FORECAST DISCUSSION
NWS MOUNT HOLLY NJ
936 AM EST SUN DEC 29 2013
.SYNOPSIS...
AN AREA OF LOW PRESSURE WILL MOVE NORTHEASTWARD ALONG THE EAST COAST
AND ACROSS THE MID ATLANTIC REGION TODAY BEFORE COMBINING WITH
ANOTHER LOW MOVING THROUGH THE GREAT LAKES AS IT MOVES INTO THE GULF
OF MAINE TONIGHT. A COLD FRONT ASSOCIATED WITH THE GREAT LAKES LOW
WILL CROSS THE REGION EARLY MONDAY MORNING. WEAK HIGH PRESSURE MAY
BRIEFLY AFFECT THE AREA LATE MONDAY INTO MONDAY NIGHT BEFORE A
CLIPPER SYSTEM MOVES ACROSS THE NORTHEAST TUESDAY. STRONGER HIGH
PRESSURE WILL BRIEFLY BUILD ACROSS THE NORTHEAST WEDNESDAY BEFORE
ANOTHER STORM SYSTEM MOVES INTO MID ATLANTIC ON THURSDAY INTO
THURSDAY NIGHT. HIGH PRESSURE IS THEN EXPECTED TO BUILD ACROSS THE
REGION BY SATURDAY.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
BAGGY LO PRES CURRENTLY EXTENDS FROM THE VA/NC BORDER NEAR
DANVILLE SOUTHWARD INTO NC WEST OF RALEIGH. WESTWARD MODEL SOLNS
LOOK BETTER. QPF VERIFICATION GFS/CAN GGEM BLEND LOOKS THE BEST.
GEOGRAPHICAL EXTENT/TIMING TO THE ECMWF.
BASED ON LATEST WXNET INFO AND FIRST TIME BEEN ABLE TO USE
NJWXNET`S NEW 5 MIN TIME STEP, IT LOOKS AS THOUGH ALL AVAILABLE
SITES WILL BE ABOVE FREEZING BY 10 AM. THUS THE CHANCES FOR ANY
FREEZING RAIN NORTH ARE ENDING VERY QUICKLY WITH PCPN JUST GETTING
TO I78 NOW. LAPS FREEZING LEVEL FAR NORTH IS AROUND 6K, SO WE
REMOVED MENTION OF SNOW AT START. USED LATEST HRRR TIMING TO BRING
HEAVIER RAIN INTO OUR CWA. MODELS HAVE NOT BEEN BUDGING MUCH FROM
THEIR QPF 1.0 TO 1.5 INCH RANGE WHICH WOULD CAUSE POOR DRAINAGE
FLOODING, BUT KEEP MOST CREEKS AND RIVERS WITHIN BANKFUL. SO FAR
SO GOOD WITH WINDS TO OUR S WHERE THE CURRENT 60KT 925MB JET IS
DEPICTED ON THE NAM, THE PCPN INDUCED INVERSION IS WORKING. NO
BIG CHANGES MADE TO TEMPS OR WINDS.
TODAY WILL BE A GOOD DAY, IF YOU ARE A DUCK! LOW PRESSURE OVER THE
SOUTHEASTERN STATES WILL MOVE NEWD DURG THE DAY AND EMERGE OFFSHORE
OFF THE DELMARVA COAST THIS AFTERNOON. IT WILL THEN CONTINUE ITS
NORTHEASTWARD MOVEMENT AND BE LOCATED NEAR LONG ISLAND THIS EVENING
AND THEN PROGRESS TWD THE CANADIAN MARITIMES TONIGHT.
THE RAIN COULD BECOME HEAVY AT TIMES DURG THE AFTN. A GENL 1 TO
1.25 INCHES OF RAIN IS EXPECTED, WITH THE HIGHEST AMTS S. WITH
GOOD WAA AHEAD OF THE LOW, TEMPS SHOULD MAKE IT WELL INTO THE 40S
AND IN SRN AND ERN SECTIONS AOA 50 DEGREES. THE ONLY EXCEPTIONS
ARE NRN AND WRN AREAS WHERE TEMPS AROUND 40 SHOULD DO IT.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 AM MONDAY/...
THE AFOREMENTIONED LOW WILL BE MOVG PAST THE REGION TONIGHT AND
PRECIP WILL BE ENDING FROM S TO N. PRECIP SHUD LINGER FOR A BIT
EARLY, ESPECIALLY ACRS THE S, BUT WILL COME TO AND END COMPLETELY BY
MID TO LATE EVENING.
&&
.LONG TERM /MONDAY THROUGH SATURDAY/...
THE DIGGING SHORT WAVE ASSOCIATED WITH THURSDAY`S SYSTEM IS NOW
PASSING SOUTH OF THE ALEUTIAN ISLANDS.
A COLD FRONT ASSOCIATED WITH THE FORMER GREAT LAKES LOW IS FORECAST
TO MOVE ACROSS THE AREA EARLY MONDAY. WE DO NOT ANTICIPATE ANY
PRECIPITATION DURING THE DAY AS THE COLUMN WILL BE DRYING. THE
VORTICITY IMPULSE SLIDING ACROSS THE AREA DURING THE DAY WILL
LIKELY ONLY INCREASE SOME MID LEVEL CLOUD COVER ACROSS THE AREA.
THE MAIN EFFECT OF THE FRONT WILL BE SOME GUSTY WINDS BEHIND IT.
WINDS COULD GUST 20-25 MPH DURING THE DAY ON MONDAY. THE STRONGEST
WIND GUSTS MAY OCCUR FROM THE MID MORNING HOURS INTO THE EARLY
AFTERNOON BEFORE DIMINISHING LATE IN THE DAY. QUIET WEATHER IS
EXPECTED FOR MONDAY NIGHT AS WEAK HIGH PRESSURE BRIEFLY BUILDS
ACROSS THE AREA.
ON TUESDAY, A WEAK CLIPPER SYSTEM IS EXPECTED TO PASS MOSTLY TO OUR
NORTH. THERE IS NOT MUCH MOISTURE FORECAST WITH THE SYSTEM, AND IT
MAY REMAIN JUST FAR ENOUGH TO OUR NORTH NOT TO BRING OUR AREA ANY
SNOW.
ON WEDNESDAY, HIGH PRESSURE MAY BRIEFLY BUILD ACROSS OUR AREA
BEFORE RETREATING BACK NORTHWARD. THIS MAY AFFECT THE AREA LONG
ENOUGH TO LIMIT THE POSSIBILITY OF PRECIPITATION UNTIL WEDNESDAY
NIGHT. MOISTURE AHEAD OF THE INLAND LOW THAT IS FORECAST TO AFFECT
THE AREA ON THURSDAY MAY GET PULLED ACROSS THE NORTHERN PORTIONS
OF OUR AREA AS EARLY AS OVERNIGHT WEDNESDAY WHICH COULD LEAD TO
SOME LIGHT SNOW ACROSS THE AREA WITH THE COLD AIR IN PLACE.
THINGS REMAIN MURKY ON THE FORECAST FOR THURSDAY. BOTH THE GFS AND
ECMWF HAVE WARMED UP WITH THEIR SOLUTIONS ON THURSDAY COMPARED TO
YESTERDAY. BOTH SHOW A LOW PRESSURE SYSTEM DEVELOPING ACROSS THE
PLAINS AND STRENGTHENING ACROSS THE MID MISSISSIPPI VALLEY AS IT
MOVES TOWARD OUR AREA. BOTH INDICATE A WEAKER COASTAL LOW DEVELOPING
DURING THE DAY THURSDAY, BEFORE THEY MERGE OFF THE MID ATLANTIC
COAST AND STRENGTHEN AS THE SYSTEM MOVES NORTHEAST THURSDAY NIGHT.
AS WE MOVE INTO THURSDAY, THE GFS NOW KEEPS THE BEST CHANCE OF
MOISTURE AND PRECIPITATION ACROSS THE NORTHERN HALF OF THE AREA,
WHILE THE ECMWF BRINGS IN THE MOISTURE ACROSS THE ENTIRE AREA. WE
WILL KEEP CHANCE POPS ACROSS THE WHOLE AREA FOR NOW WITH THE
HIGHEST POPS GENERALLY ACROSS THE NORTHERN HALF. WITH THE GUIDANCE
COMING IN WARMER, THIS WILL PUSH A RAIN/SNOW LINE CLOSER TO THE
I-95 CORRIDOR. DEPENDING ON HOW STRONG THE COLD PUSH IS FROM THE
HIGH RETREATING TO OUR NORTH ON WEDNESDAY NIGHT WILL HAVE AN
EFFECT ON WHERE THIS SETS UP.
THE GFS PULLS THE PRECIPITATION OUT OF THE AREA OVERNIGHT
THURSDAY, BUT THE ECMWF KEEPS IT AROUND THROUGH EARLY FRIDAY, SO
WE WILL KEEP A CHANCE OF PRECIPITATION IN THE FORECAST THROUGH
EARLY FRIDAY. FRIDAY INTO SATURDAY SHOULD BE PRECIPITATION FREE AS
HIGH PRESSURE BUILDS ACROSS THE EAST COAST.
&&
.AVIATION /14Z SUNDAY THROUGH THURSDAY/...
THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG, KILG,
KMIV, KACY AND SURROUNDING AREAS.
VFR CONDS EARLY WILL DETERIORATE LATER THIS MORNING TO MVFR AND IFR
AS LOW PRESSURE MOVES FROM THE SOUTHEASTERN STATES TO A POSITION OFF
THE DELMARVA AND THEN TO THE CANADIAN MARITIMES TONIGHT. AS THE LOW
MOVES ACRS THE REGION, RAIN WILL DEVELOP AND COULD BE HEAVY AT
TIMES, ESPECIALLY THIS AFTN. CIGS WILL LOWER AND ITS PSBL THERE CUD
BE SOME REDUCED VSBYS AS WELL ESPECIALLY IN PDS OF HVY RAIN. THE
WIND WILL START OFF SW, BECOME MORE SE OR E AS THE LOW GETS CLOSER
AND THEN SWING AROUND TO THE NW AND BECOME A BIT GUSTY AS THE LOW
PULLS AWAY TONIGHT. GUSTS COULD REACH AS HIGH AS 15 TO 20 KTS.
OUTLOOK...
MONDAY...VFR. GUSTY NORTHWEST WINDS AROUND 25 KNOTS.
MONDAY NIGHT THROUGH WEDNESDAY...VFR.
WEDNESDAY NIGHT-THURSDAY...MVFR DEVELOPING WITH IFR CONDITIONS
POSSIBLE WITH SNOW OR MIXED PRECIPITATION.
&&
.MARINE...
THE GALE WARNING AND SCA WILL REMAIN IN EFFECT UNCHANGED. AN AREA
OF LOW PRESSURE, CURRENTLY OVER THE SERN CONUS WILL MOVE NEWD TO A
POSN OFF THE DELMARVA THIS AFTN THEN NR LI THIS EVE AND OFF THE CAN
MARITIMES TONIGHT. RAIN WILL ACCOMPANY THE LOW AND BOTH SEAS AND
WIND WILL INCREASE. WIND COULD GUST AS HIGH AS 35 TO 40 KT AND SEAS
IN THE 6 TO 9 FT RANGE ARE PSBL ON THE OCEAN.
OUTLOOK...
MONDAY...SCA CONDITIONS POSSIBLE.
MONDAY NIGHT THROUGH WEDNESDAY...MOSTLY SUB ADVISORY CONDITIONS...EXCEPT
POSSIBLE ADVISORY LEVEL ON LATE TUESDAY INTO EARLY TUESDAY NIGHT.
THURSDAY...A RETURN TO ADVISORY CONDITIONS POSSIBLE WITH A STORM
STRENGTHENING ACROSS THE AREA.
THURSDAY NIGHT-FRIDAY...GALE FORCE WIND GUSTS POSSIBLE
&&
.PHI WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NJ...NONE.
DE...NONE.
MD...NONE.
MARINE...GALE WARNING FROM 1 PM THIS AFTERNOON TO 10 PM EST THIS
EVENING FOR ANZ450>455.
SMALL CRAFT ADVISORY FROM 1 PM THIS AFTERNOON TO 6 PM EST
MONDAY FOR ANZ430-431.
&&
$$
SYNOPSIS...ROBERTSON
NEAR TERM...GIGI/NIERENBERG
SHORT TERM...NIERENBERG
LONG TERM...ROBERTSON
AVIATION...NIERENBERG/ROBERTSON
MARINE...NIERENBERG/ROBERTSON
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
618 AM CST SUN DEC 29 2013
.DISCUSSION...
342 AM CST
WINTER 2013-2014 IS RETURNING THIS MORNING AFTER A BRIEF 36 HOUR
HIATUS AND THIS PRESENTS PLENTY OF FORECAST CHALLENGES THROUGH THE
START TO THE NEW YEAR. IN PARTICULAR...TEMPERATURES...WIND
CHILLS...AND MULTIPLE ACCUMULATING SNOW CHANCES ARE WHAT THE
EMPHASIS OF TIME WAS SPENT ON THIS MORNING.
THE 1006 MB SURFACE LOW ACROSS LOWER MI EARLY THIS MORNING
CONTINUES TO USHER AN ARCTIC FRONT EASTWARD...WHICH ACTUALLY IS
GETTING MORE OF A PUSH BY THE ARCTIC HIGH EVOLVING SOUTHWARD
BEHIND THE FRONT. THIS BOUNDARY WILL CLEAR THE FORECAST AREA BY
LATE MORNING AND OBSERVATIONS ACROSS EASTERN IOWA INDICATE AROUND
A 15 DEGREE DROP IN THREE HOURS WITH THE FRONT. THIS DEGREE OF
COLD AIR ADVECTION WILL LIKELY EASE SOME...BUT NONETHELESS FALLING
TEMPERATURES THROUGH THE DAY WILL OCCUR AS STRONG PRESSURE RISES
AND PRONOUNCED LOW LEVEL THICKNESS FALLS DRIVE THE BOUNDARY
EASTWARD. THE FIRST SINGLE DIGITS SHOULD ARRIVE IN NORTH CENTRAL
IL DURING MID-AFTERNOON OR SO...WITH SUBZERO READINGS LIKELY BY
MID-EVE.
THE LOW-LEVEL LAPSE RATES WILL OBVIOUSLY QUICKLY STEEPEN BEHIND
FROPA AND EARLY MORNING SATELLITE INDICATES A WIDESPREAD AREA OF
1000-1500 FT STRATOCU CIGS THAT LINE UP WELL WITH THE 1000-850MB
COLD AIR ADVECTION BEHIND THE FRONT. AMDAR SOUNDINGS FROM MSP SHOW
THIS SATURATED LAYER TO BE QUITE SHALLOW WHICH RAP...NAM...AND
LOCAL ARW SOUNDINGS INDICATE WILL INDEED BE THE CASE OVER US THROUGH
TODAY. THIS HAS APPARENTLY STILL BEEN ENOUGH TO GENERATE FLURRIES
AND OCCASIONALLY LIGHT SNOW TO OUR WEST AND NORTHWEST AS SEEN ON
OBS AND THROUGH WIDESPREAD LIGHT ECHOES ON THE ARX AND DMX RADARS.
CONDITIONS MAY BECOME MORE FAVORABLE FOR SNOW SHOWERS DURING THE
DAYTIME TODAY...AND WITH A LITTLE HELP FROM THE MID-LEVEL
VORT...WE CONTINUE TO EXPECT AT LEAST SCATTERED LIGHT SNOW
SHOWERS NAMELY ACROSS THE NORTHERN FORECAST AREA. AROUND ONE HALF
INCH THROUGH THE DAY COULD BE SEEN WITH THESE.
THE CENTER OF THE ARCTIC HIGH IS EXPECTED TO DEVELOP INTO NORTHERN
MO TONIGHT...WITH NVA AND A STRENGTHENING SUBSIDENCE INVERSION
LIKELY HELPING TO ERODE MOST CLOUDS OVER THE CWA AS THE COLUMN
CONTINUES TO DRY. THIS HIGH PLACEMENT WILL STILL ALLOW FOR SOME
WIND COMPONENT AND DANGEROUSLY COLD CONDITIONS ARE EXPECTED WITH
THE COMBINATION OF TEMPERATURES AND WIND. A WIND CHILL ADVISORY
HAS BEEN ISSUED FOR TONIGHT INTO MONDAY MORNING FOR MUCH OF THE
OUTLYING IL CWA WITH WIDESPREAD WIND CHILLS OF -20 TO -30
DEVELOPING AND PERSISTING.
GOING FORWARD INTO THE WEEK...A HANDFUL OF FACTORS ARE IN PLACE
TO CREATE WHAT IS LOOKING LIKE AN INCREASINGLY UNSETTLED PATTERN.
THE HEART OF THE HUDSON BAY TROUGH REACHES THREE STANDARDIZED
ANOMALIES BELOW NORMAL WITH REGARD TO ITS 500MB HEIGHT CENTER OF
AROUND 481DM AND CONTINUED CROSS-POLAR FLOW IS ADVERTISED THROUGH
MID-WEEK BASICALLY KEEPING ITS DEPTH ESTABLISHED. THIS IN ITSELF
ALLOWS FOR STRONG AMPLIFICATION OF THE FLOW PATTERN ACROSS CENTRAL
NORTH AMERICA. ALSO...THE JET ORIENTATION IS SUCH THAT MULTIPLE
PERTURBATIONS WILL NOT ONLY MOVE OVER THE MIDWEST/GREAT LAKES BUT
LIKELY DEEPEN AND POTENTIALLY EVEN PIVOT OVER THE AREA GIVEN THE
LOCATION OF THE BAROCLINIC ZONE. AND FINALLY THAT BAROCLINIC ZONE
IS AROUND THE DENDRITIC GROWTH ZONE MAGNITUDE AND FOR A DECENTLY
LARGE DEPTH AT TIMES WITHIN THE ENVELOPE OF FORECAST GUIDANCE.
ALL IN ALL HAVE TRIED TO REFINE DETAIL THE MOST WITH THE FIRST
WAVES ON MONDAY NIGHT AND TUESDAY NIGHT...WHICH GUIDANCE IS IN
FAIRLY GOOD AGREEMENT ABOUT TIME-WISE. DETAIL WISE SOME NOTABLE
DIFFERENCES THAT COULD YIELD TO A SHARP GRADIENT IN SNOW
PLACEMENT...WHICH WITH A TAUNT BAROCLINIC ZONE CAN CERTAINLY
HAPPEN. BOTH WAVES HAVE LIMITED OVERALL FORCING FOR EVEN PROLONGED
MODERATE SNOW...BUT HAVE GOOD POTENTIAL TO HAVE HIGHER THAN NORMAL
SNOW-TO-LIQUID RATIOS. HAVE BOOSTED POPS MONDAY NIGHT WITH AROUND
AN INCH FORECAST PRESENTLY NEAR THE WI BORDER. AGAIN THIS COULD
SHIFT NORTH OR SOUTH...BUT THE OVERALL MAXIMUM MAGNITUDE OF AROUND
1 TO MAYBE 2 INCHES HAS DECENT CONFIDENCE. FOR TUESDAY NIGHT THE
WAVE IS LESS AMPLIFIED BUT APPEARS TO HAVE FRONTOGENESIS ON ITS
SIDE TO PRODUCE A SMALLER SCALE MORE MODERATE SNOW. OBVIOUSLY
PLACEMENT ON THIS IS LOW CONFIDENCE...BUT DO HAVE SOME EARLY
PROJECTED AMOUNTS OF 1-3 INCHES WITH THIS AND IN TIME THE GRADIENT
OF SNOWFALL AMOUNTS LIKELY WILL NEED TO BE TIGHTENED UP. BUT
PLACEMENT WITH THIS IS QUITE LOW CONFIDENCE RIGHT NOW.
NEWS YEARS DAY INTO POSSIBLY THURSDAY IS LOOKING MORE ACTIVE
ACROSS THE MIDDLE OF THE COUNTRY IN MANY OF THE MODEL MEMBERS AS A
MORE ROBUST WAVE DEVELOPS TO THE WEST AND POSSIBLY OVER THE AREA.
ALMOST A COUPLED JET STRUCTURE IS ADVERTISED BY THE EC AND GFS FOR
00Z THU WHEN THE MID-LEVEL WAVE AND SURFACE LOWS ALL ARE
PROJECTED TO COME TO SHAPE IN THE REGION. WITH THE 850MB LOW EVEN
BEING ADVERTISED AS CLOSED...DEEPENING...AND SLOWLY MOVING ON THE
00Z GFS AND EC...THE ELEMENTS OF SNOW DURATION AND INTENSITY LOOK
LIKE THEY MAY BOTH BE REALIZED ACROSS SOMEWHERE IN THE REGION.
RIGHT NOW...MOST DETERMINISTIC MODELS AND THE GEFS DO FAVOR ARE
FORECAST AREA TO SEE AT LEAST SOME OF THIS AND HAVE ADDED SOME
LIKELY POPS ALREADY ON WEDNESDAY NIGHT. WAY TOO EARLY TO GET INTO
SPECIFICS AS SHIFTS WITH THIS ARE INEVITABLE. BUT SOMETHING
CERTAINLY TO KEEP AN EYE ON AS WE NEAR THE NEW YEAR.
FOR TEMPERATURES CONTINUE TO UNDERCUT A MODEL BLEND BY 2-3 DEGREES
GOING FORWARD...MOST PARTICULARLY OVER NORTH CENTRAL ILLINOIS AND
THE FAR NORTHERN CHICAGO METRO WHERE SNOW COVER REMAINS AND WILL
LIKELY ONLY INCREASE. IF SNOW COVER IS REALIZED OVER THE MUCH OF
THE AREA...THEN THE LOW TEMPERATURES ON FRIDAY AND SATURDAY
MORNINGS ARE LIKELY FAR TOO MILD.
MTF
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 12Z...
* WIND VEERING AND INCREASING SIGNIFICANTLY FROM W TO NNW-N BY
MID MORNING.
* MVFR CIGS OVERSPREAD THE LOCAL AREA DURING THE EARLY MORNING
WITH PERIODS OF IFR CIGS AND FLURRIES MID TO LATE MORNING.
* PERIOD OF VERY LIGHT SNOW LIKELY DURING FIRST PART OF AFTERNOON.
TRS
//DISCUSSION...UPDATED 12Z...
COLD FRONT KNOCKING AT THE DOOR OF THE ORD AND MDW TERMINALS WITH
WINDS JUST SHIFTING TO OUT OF THE W BETWEEN 11Z AND 12Z...WHILE
RFD SHIFTED TO WNW AT 1030Z. THIS WIND SHIFT IS THE COLD FRONT
MOVING IN BUT THE STRONG GUSTY NW-N WINDS WILL LAG BEHIND THE
FROPA BY A COUPLE HOURS AND ARE CURRENTLY SPREADING INTO FAR
SOUTHERN WI AS WELL AS FAR NW IL.
WITH THE COLD FRONT COMES A DECK OF LOWER END MVFR AND HIGHER END
IFR CIGS. INITIALLY NOT MUCH MOISTURE AVAILABLE FOR PRECIP BUT
PROGS DO SHOW INCREASING MID AND UPPER LEVEL MOISTURE MID MORNING
INTO EARLY AFTERNOON. WITH STRONG COLD AIR ADVECTION SPREADING SE
ACROSS THE AREA AS WELL AS ANOTHER MINOR MID LEVEL SHORT WAVE
TROUGH...CURRENTLY OVER THE DAKOTAS AND FAR NW MN...APPROACHING
THE AREA THIS MORNING AND MOVING OVERHEAD BY LATE AFTERNOON
ANTICIPATE MAINLY FLURRIES OR VERY LIGHT SNOW BUT WITH A PERIOD
OF SLIGHTLY HEAVIER LIGHT SNOW ASSOCIATED WITH THE SECOND SHORT
WAVE MIDDAY-EARLY AFTERNOON THOUGH LITTLE ACCUMULATION.
NW WIND TO BE DROPPING LATE AFTERNOON AND THIS EVE WITH AS
LESSENING OF THE GRADIENT AS LOW PRESSURE MOVES FURTHER E TO N OF
LAKE ONTARIO BY 00Z AND A LARGE AREA OF HIGH PRESSURE BUILDING SE
OVER THE PLAINS TODAY MOVES E TO THE UPPER MIDWEST AND MID MS
VALLEY BY 12Z MON.
WITH STRONG SUBSIDENCE AND DRYING OF THE LOW LEVELS LATE TODAY
AND TONIGHT THE MVFR AND IFR STRATOCUMULUS IS EXPECTED TO CLEAR
OUT DURING THE OVERNIGHT.
TRS
//ORD AND MDW CONFIDENCE...UPDATED 12Z...
* HIGH CONFIDENCE IN OVERALL TRENDS.
* MODERATE CONFIDENCE IN TIMING OF PERIOD OF IFR CIGS...LIGHT
SNOW...SPEED OF MAX GUSTINESS.
* LOW CONFIDENCE IN TIMING OF LOSS OF CIGS TONIGHT.
TRS
//OUTLOOK FOR ORD/MDW FOR 00Z TUESDAY-12Z SUNDAY...UPDATED 12Z...
MONDAY NIGHT...LIGHT SNOW LIKELY IN THE EVENING WITH A PERIOD OF
MVFR AND IFR CONDITIONS.
TUESDAY...CHANCE OF LIGHT SNOW LATE AFTERNOON...SNOW LIKELY TUE
NIGHT. MVFR BECOMING IFR
WEDNESDAY...CHANCE OF SNOW. MVFR.
THURSDAY...CHANCE OF SNOW. MVFR.
FRIDAY...VFR.
SATURDAY...VFR.
TRS
&&
.MARINE...
433 AM CST
A LOW OVER NORTHERN LOWER MI WILL CONTINUE EASTWARD...DRAGGING A
STRONG COLD FRONT DOWN PAST THE SOUTH TIP OF THE LAKE EARLY TO
MID MORNING...WHILE A STRONG HIGH OVER THE NORTHERN AND CENTRAL
PLAINS SPREADS S AND E...AND ACROSS THE MID MS VALLEY ON MON.
FOLLOWING THE PASSAGE OF THE COLD FRONT IS VERY COLD AIR
SPREADING ACROSS THE UPPER MIDWEST...THE WESTERN GREAT LAKES AND
THE MID MS VALLEY. THE COMBINATION OF THE VERY STRONG COLD AIR
ADVECTION AND A STRONG PRESSURE GRADIENT WILL LEAD TO NW TO N
GALES DEVELOPING ACROSS THE N PORTION OF THE LAKE BY
DAWN...SPREADING DOWN TO THE FAR S PORTION BY LATE MORNING.
THE VERY COLD AIR...STRONG WINDS AND HIGH WAVES WILL LEAD TO THE
POTENTIAL FOR MODERATE TO HEAVY FREEZING SPRAY...WITH THE
GREATEST CHANCE FOR HEAVY FREEZING SPRAY TO OCCUR DURING THIS
AFTERNOON AND THIS EVENING AS TEMPERATURES DROP INTO THE TEENS
AND LOWER 20S. THERE IS THE POTENTIAL FOR SOME HEAVY SPRAY TO
LINGER AS WINDS DROP BELOW GALE FORCE DUE TO THE SLOWER DECREASE
IN WAVE HEIGHTS AND THE ADVECTION OF EVEN COLDER AIR WELL BEHIND
THE FRONT.
ANOTHER ARCTIC HIGH BUILDING INTO THE NORTHERN PLAINS TUE WILL
RESULT IN STRONG NW WINDS ON LAKE MI TUE AND TUE NIGHT ALTHOUGH
THIS SYSTEM SHOULD BE ACCOMPANIED BY A LESSER PRESSURE GRADIENT
AND THE AIR MASS WILL NOT BE QUITE AS COLD...SO ANOTHER ROUND
GALES AND FREEZING SPRAY IS NOT ANTICIPATED AT THIS TIME.
FOR THE NEARSHORE WATERS...THE BETTER CHANGE FOR GALES TODAY
WILL BE OVER THE IN WATERS DUE TO THE DIRECT N TO NW FETCH
PREDOMINANTLY OVER ALL WATER...WHILE THE IL NEARSHORE WATERS
SHOULD REMAIN BELOW GALE FORCE DUE TO SLIGHTLY WEAKER FLOW OFF
LAND. THE GREATEST RISK OF HEAVY FREEZING SPRAY WILL BE ON THE IN
NEARSHORE WATERS...THOUGH ON THE IL NEARSHORE WATERS THERE WILL
LIKELY HEAVY FREEZING SPRAY AS ONE NEARS THE 5 NM FROM SHORE
BOUNDARY AS THE LARGEST WAVES ON THE IL WATERS WILL BE FOUND OUT
NEAR THE OPEN WATERS.
WINDS AND WAVES WILL DIMINISH AS THE HIGH SPREADS E MON NIGHT AND
TUE...BUT ANOTHER LOW IS EXPECTED TO DEVELOP OVER THE NORTHERN
PLAINS MON MORNING AND TRACK E ACROSS NORTHERN IL MON
NIGHT...CONTINUING TO THE EASTERN GREAT LAKES TUE MORNING.
TRS
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...WIND CHILL ADVISORY...ILZ003-ILZ004-ILZ005-ILZ006-ILZ008-ILZ010-
ILZ011-ILZ012-ILZ019-ILZ020-ILZ021-ILZ032...9 PM SUNDAY TO
NOON MONDAY.
IN...NONE.
LM...GALE WARNING...LMZ080-LMZ567-LMZ669-LMZ671-LMZ673-LMZ675-LMZ744-
LMZ745-LMZ777-LMZ779-LMZ868-LMZ870-LMZ872-LMZ874-LMZ876-
LMZ878...9 AM SUNDAY TO 9 PM SUNDAY.
HEAVY FREEZING SPRAY WARNING...LMZ080-LMZ567-LMZ669-LMZ671-
LMZ673-LMZ675-LMZ740-LMZ741-LMZ742-LMZ743-LMZ744-LMZ745-
LMZ777-LMZ779-LMZ868-LMZ870-LMZ872-LMZ874-LMZ876-LMZ878...9
AM SUNDAY TO MIDNIGHT MONDAY.
GALE WARNING...LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-LMZ565 UNTIL 6
PM SUNDAY.
HEAVY FREEZING SPRAY WARNING...LMZ261-LMZ362-LMZ364-LMZ366-
LMZ563-LMZ565 UNTIL MIDNIGHT MONDAY.
SMALL CRAFT ADVISORY...LMZ740-LMZ741-LMZ742-LMZ743...9 AM SUNDAY
TO 4 AM MONDAY.
&&
$$
VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)
FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/US.NATIONALWEATHERSERVICE.CHICAGO.GOV
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[top]
Area Forecast Discussion
National Weather Service Lincoln IL
503 AM CST Sun Dec 29 2013
.DISCUSSION...
ISSUED 330 AM CST Sun Dec 29 2013
Will issue a wind chill advisory for northern 10 counties from 9
pm this evening until 9 am Monday morning for wind chills of 15 to
20 below zero. The wind chill advisory is roughly along and north
of a Rushville to Bloomington line.
SHORT TERM...Today through Tuesday night
Arctic cold front extends from 1005 mb low pressure over northern
lower MI through southeast WI into NW IL (recently passing se of
Galesburg) and into central MO. Relatively mild temps in the mid
to upper 30s over central and southeast IL with 41F at Robinson.
Area of light rain over far southeast IL (along and southeast of a
Robinson to Flora line) and into KY/TN and southern IN and
associated with isentropic lift ahead of weakening 558 dm 500 mb
low over the red river valley along the OK/Texas border. This
upper level low to continue to weaken/open up as it ejects into
the TN valley today taking its light rain out of IL early this
morning. Main weather story today will be strong arctic cold front
that quickly sweeps se through central IL through mid morning and
passes se of the Wabash river late this morning. Expect temps to
drop behind the cold front with brisk/gusty nw winds behind front
as temps fall to 10F at Galesburg by sunset and near 30F by
Lawrenceville in far southeast IL. NAM models remains dry today
but some other high res models like RAP, HRRR and SREF show
patches of light qpf over mainly northern counties from 15Z-22Z
today. Mainly think scattered flurries with a few light snow
showers possible over mainly northern counties today and not
expecting any accumulations.
Clouds decrease tonight and very cold lows in the single digits
below zero over IL river valley where wind chills reach 15 to 20
below zero by late evening until around 9 am Monday morning. Will
issue a wind chill advisory as stated earlier. Clouds to increase
from nw during Monday and quite cold with highs in the teens over
central IL and lower 20s in southeast IL. A northern stream short
wave to bring chance of light snow to northern areas Monday night.
With another one bringing chances of light snow to northern areas
Tue afternoon and over much of area Tue night with some light snow
accumulations possible mainly north of I-74. Temps to stay well
below normal into the middle of the week.
LONG TERM...Wednesday through Sunday
Medium to long range forecast models and ensembles continue to
show a strong upper level trof digging back into the MS river
valley Wednesday night and Thursday...and models trending with a
deepening surface low pressure ejecting from the central plains
into the Ohio river valley by Thursday morning. Accumulating snows
appear more likely now to fall north of this low pressure track
over central IL and increased pops north Wednesday and across area
Wed night, and best chances of snow shifting east of IL during
Thursday. Trended temperatures colder behind this storm system Thu
night and Friday as below normal temps continue. Large upper level
trof shifts east of IL Fri/Sat with temps moderating closer to
normal next weekend.
07
&&
.AVIATION...
ISSUED 503 AM CST Sun Dec 29 2013
Arctic cold front is near Illinois river at 05z. KPIA shows wind
shift to 310 and gusting. Cigs currently MVFR but upstream
observations indicate a fall to IFR shortly after frontal passage
and persisting for 4-5 hours. These conditions will likely spread
southeast through the remainder of the terminals by 14z. WFO DVN
indicates very small ice crystals occurring behind the front that
are not being picked up by ASOS Present Weather Sensor though some
reduction is being measured.
NAM Time heights indicated thinning of boundary layer RH around
00z at KPIA moving east to KCMI by 04z. Am a little skeptical of
clearing given the time of day and the shallow nature of the air
mass. For now will scatter out low clouds and go skc by morning,
but later forecasts may need to go more pessimistic.
Barker
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
WIND CHILL ADVISORY from 9 PM this evening to 9 AM CST Monday
FOR ILZ027>031-036>038-040-041.
&&
$$
AREA FORECAST DISCUSSION
NWS QUAD CITIES IA IL
842 AM CST SUN DEC 29 2013
.UPDATE...
ISSUED AT 840 AM CST SUN DEC 29 2013
A QUICK UPDATE SENT TO SLIGHTLY CHANGE THE OUTLINE OF WIND CHILL
ADVISORY COUNTIES IN WEST CENTRAL ILLINOIS. WE HAVE ADDED THE
COUNTIES OF DES MOINES...HENDERSON...WARREN...AND MCDONOUGH. WHILE
CRITERIA IS MARGINAL FOR WIND CHILLS...THE COLLABORATION WITH
SURROUNDING OFFICES WILL CONVEY A MUCH MORE CONSISTENT MESSAGE
WITH THE INCLUSION OF THESE COUNTIES.
ERVIN
UPDATE ISSUED AT 726 AM CST SUN DEC 29 2013
BASED ON RADAR DUAL POL DATA IN CONCERT WITH WEAK VISIBILITY
RESTRICTIONS FROM THE LIGHT PRECIPITATION...HAVE ADDED PATCHY
FREEZING DRIZZLE THROUGH MID MORNING TO THE FORECAST.
IF THE TRENDS IN THE RAP ARE CORRECT...THE CURRENT FORCING MOVING
THROUGH THE AREA WITH DRIER AIR ALOFT IS PRODUCING SOME LIGHT SNOW
MIXED WITH VERY LIGHT FREEZING DRIZZLE. THIS SHALLOW MOISTURE
SHOULD EXIT THE AREA SHORTLY AFTER MID MORNING.
ACROSS CENTRAL IOWA...THERE IS ANOTHER AREA OF FORCING BUT THE
MOISTURE IS A BIT DEEPER BASED ON CONDENSATION PRESSURE DEFICITS.
HERE PRECIPITATION IS STILL LIGHT BUT OBSERVATIONS AND RADAR DATA
SUGGEST MORE FLURRIES OR VERY LIGHT SNOW INSTEAD OF FREEZING DRIZZLE.
REGARDING THE CURRENT HEADLINES...THE COLDER AIR IS NOT MOVING IN
AS FAST AS THE SHORT RANGE MODEL TRENDS HAVE BEEN SUGGESTING. THIS
OBSERVATIONAL TREND BRINGS QUESTIONS AS TO WHETHER OR NOT 15 BELOW
ZERO IS ACHIEVABLE TONIGHT IN AREAS WEST OF A DUBUQUE TO IOWA CITY
LINE. IF THIS IS THE CASE...THEN WIND CHILLS WOULD NOT PROBABLY
NOT EXCEED 30 BELOW ZERO EITHER. THIS AREA IS RIGHT ON THE CUSP
BETWEEN AN ADVISORY AND A WARNING FOR WIND CHILL. TRENDS THROUGH
THE DAY WILL BE CRITICAL IN DETERMINING WHICH WAY THE HEADLINE
WILL EVENTUALLY GO FOR TONIGHT.
UPDATE ISSUED AT 532 AM CST SUN DEC 29 2013
TEMPERATURES ARE FALLING BUT NOT NEARLY AS FAST AS PREVIOUSLY
THOUGHT. OVERNIGHT LOWS ARE STILL EXPECTED 7-9 AM WITH HIGHS 8-10
AM THAT ARE ONLY 1-2 DEGREES ABOVE THE OVERNIGHT LOWS.
TEMPERATURES ARE THEN EXPECTED TO SLOWLY FALL THROUGH THE DAY.
RADAR AND VISIBILITY TRENDS ARE SUGGESTING THE CURRENT VERY LIGHT
PRECIPITATION WILL BE MOVING EAST OF THE MISSISSIPPI THIS MORNING
WITH POSSIBLY SOME FLURRIES. BASED ON DATA FROM THE 12Z
SOUNDING...VERY LIGHT FREEZING DRIZZLE CANNOT BE RULED OUT EITHER.
ALTHOUGH PAVEMENT TEMPERATURES ARE GENERALLY AT OR BELOW
FREEZING...THE STRONG WIND IS PROMOTING EVAPORATION WHICH MAY
LIMIT OR REDUCE ANY FREEZING DRIZZLE ACCUMULATION ON ROADS.
&&
.SYNOPSIS...
ISSUED AT 317 AM CST SUN DEC 29 2013
06Z SFC ANALYSIS HAD A LOW IN CENTRAL WISCONSIN WITH A WEAK TROF
RUNNING FROM THE LOW INTO NORTHEAST MISSOURI. THE ARCTIC FRONT RAN
FROM WESTERN UPPER MICHIGAN...TO KANSAS CITY... AND THEN TO AROUND
KAMA. DEW POINTS ALONG AND AHEAD OF THE ARCTIC FRONT WERE IN THE
20S AND 30S WITH TEENS AND COLDER BEHIND THE FRONT INTO THE PLAINS.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 317 AM CST SUN DEC 29 2013
THE ARCTIC FRONT IS GENERALLY ALONG THE MISSISSIPPI AT 09Z AND
SHOULD BE OVER THE FAR EASTERN AREAS BY SUNRISE. WINDS JUMP
QUICKLY BEHIND THE FRONT WITH SUSTAINED WINDS OF 15 TO 25 MPH WITH
GUSTS OVER 30 MPH. LOW TEMPERATURES THIS MORNING WILL OCCUR 7-9 AM
WITH MAX TEMPERATURES IN THE 8-10 AM TIME FRAME. AT BEST MOST OF
THE AREA WILL ONLY SEEN A 1-2 DEGREE RISE BEFORE TEMPERATURES
START FALLING THROUGH THE DAY.
MOISTURE IN THE LOWER ATMOSPHERE IS NOT AS GREAT AS ORIGINALLY
SUGGESTED. THUS MAINLY FLURRIES WILL BE SEEN DURING THE DAY WITH
SOME AREAS OF LIGHT SNOW. AT BEST ANY ACCUMULATION WOULD BE A DUSTING.
THE CURRENT WIND CHILL ADVISORY HAS BEEN DELAYED UNTIL LATE
MORNING BASED ON EXPECTED TEMPERATURES AND WINDS.
TONIGHT...DRY CONDITIONS ARE EXPECTED AS THE NEXT ARCTIC HIGH
BUILDS INTO THE MIDWEST. BASED ON PROJECTED LOWS AND WIND...AREAS
GENERALLY EAST OF THE CURRENT WIND CHILL ADVISORY WILL MET WIND
CHILL CRITERIA TONIGHT INTO MONDAY MORNING.
AREAS WEST OF A DUBUQUE TO IOWA CITY LINE MAY SEE WIND CHILLS
EXCEED 30 BELOW TONIGHT BEFORE THE ARRIVAL OF THE ARCTIC HIGH. IF
THIS OCCURS...THEN A WIND CHILL WARNING WOULD BE NEEDED FOR THAT
AREA. HOWEVER...TEMPERATURES MAY NOT DROP OFF AS QUICKLY AS
FORECAST AND WINDS MAY NOT BE AS STRONG WHICH WOULD RESULT IN WIND
CHILLS OF ONLY 30 BELOW ZERO. THIS SITUATION WILL HAVE TO BE MONITORED
CAREFULLY DURING THE DAY IN CASE THE ADVISORY WOULD NEED TO BE UPGRADED.
.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 317 AM CST SUN DEC 29 2013
SNOWIER PATTERN APPEARS IN STORE FOR THE AREA THROUGHOUT THE
EXTENDED AS SEVERAL CLIPPER SYSTEMS ARE SHUTTLED DOWN
OVER THE REGION IN ACTIVE NORTHWEST FLOW.
TEMPS THROUGHOUT THE PERIOD TO REMAIN WELL BELOW NORMAL IN
THE NORTHWEST FLOW. CHALLENGE IN TIME WILL BE IMPACT
OF NEGATIVE FEEDBACK FROM FRESH NEW SNOW COVER ON TEMPS.
IF SOME AREAS SEE 2-5+ INCHES OF NEW SNOW AS IS LOOKING
QUITE REASONABLE AT THIS TIME THEN GOING TEMPS ESPECIALLY
OVER THE LATTER HALF OF THE PERIOD WILL LIKELY NEED TO BE
LOWERED.
FIRST ROUND OF ACCUMULATING SNOW ANTICIPATED MON AFTN/EVE
ESPECIALLY ACROSS THE NORTH 1/2 TO POSSIBLY 2/3RDS OF CWA WITH
CLIPPER SYSTEM AND ATTENDANT WARM ADVECTION. LIQUID PCPN
AMOUNTS LOOK TO BE LIGHT AND LESS THAN 0.1 INCH BUT HIGH SNOW
TO LIQUID RATIOS OF 15-20+:1 SUPPORTIVE OF AN INCH OR TWO
OF ACCUMULATION WITH THE HIGHER AMOUNTS FAVORING AREAS NORTH
OF I-80.
ANOTHER CLIPPER SYSTEM THEN FOLLOWS ABOUT 24+ HRS LATER OR LATE
TUE AFTN/NGT WITH SIMILAR LIGHT QPF AND HIGH RATIO EVENT
FOR ANOTHER INCH OR POSSIBLY TWO OF SNOW ESPECIALLY NEAR TO
NORTH OF I-80.
MODELS ARE THEN COMING INTO BETTER AGREEMENT ON A MUCH STRONGER
SYSTEM FOR WED/WED NGT. BETTER MOISTURE AND GOOD DYNAMICS IN
TERMS OF DIGGING SHORTWAVE AND COUPLED UPPER JET STRUCTURE
SUGGESTIVE OF MODERATE QPF EVENT OF 0.25-0.4 INCH POSSIBLE WHICH
WITH SNOW TO LIQUID RATIOS OF 13-17:1 WOULD RESULT IN 3-6 INCH
POTENTIAL SNOW ACCUMS. STILL WAY EARLY IN THE GAME AND OF COURSE
A LOT OF UNCERTAINTY WITH TRACK... BUT THE MAGNITUDE OF FORCING
AND MOISTURE WILL MAKE THIS ONE TO WATCH IN THE COMING DAYS.
MODELS THEN SUGGEST POTENTIAL OF A QUITE PERIOD LATE WEEK AND
INTO NEXT WEEKEND AS THE FLOW PATTERN APPEARS SET TO UNDERGO
TRANSITION TO SOUTHWESTERLY FLOW BY EARLY NEXT WEEK. LATEST RUNS
OF GFS AND ECMWF THEN SHOW AN EVEN STRONGER SYSTEM EJECTING FROM
THE SOUTHWEST AND THROUGH THE CENTRAL CONUS EARLY NEXT WEEK WHICH
COULD BRING MORE SNOW OR A WINTRY MIX TO THE REGION.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z MONDAY MORNING)
ISSUED AT 532 AM CST SUN DEC 29 2013
VERY LIGHT PRECIPITATION...IN THE FORM OF FLURRIES OR POSSIBLY
FZDZ...IS OCCURRING ACROSS IOWA AND NORTHERN ILLINOIS BEHIND THE
ARCTIC FRONT. PRESENT WEATHER SENSORS ON OBSERVATIONS ARE NOT
PICKING UP THE LIGHT PRECIPITATION BUT VISIBILITY SENSORS ARE BY
INDICATING A REDUCTION BELOW 10SM. SO...IFR TO LIFR CONDITIONS
WITH VCSH WILL SLOWLY IMPROVE TO MVFR AND THEN VFR THROUGH 00Z/30.
ARCTIC HIGH PRESSURE BUILDING INTO THE MIDWEST AFT 00Z/30 WILL
RESULT IN VFR CONDITIONS AND WINDS DROPPING UNDER 10 KNOTS.
&&
.DVN WATCHES/WARNINGS/ADVISORIES...
IA...WIND CHILL ADVISORY FROM 5 PM THIS AFTERNOON TO NOON CST MONDAY
FOR CLINTON-DES MOINES-HENRY IA-JACKSON-LOUISA-MUSCATINE-
SCOTT.
WIND CHILL ADVISORY UNTIL NOON CST MONDAY FOR BENTON-BUCHANAN-
CEDAR-DELAWARE-DUBUQUE-IOWA-JEFFERSON-JOHNSON-JONES-KEOKUK-
LINN-WASHINGTON.
IL...WIND CHILL ADVISORY FROM 5 PM THIS AFTERNOON TO NOON CST MONDAY
FOR BUREAU-CARROLL-HENDERSON-HENRY IL-JO DAVIESS-MCDONOUGH-
MERCER-PUTNAM-ROCK ISLAND-STEPHENSON-WARREN-WHITESIDE.
MO...NONE.
&&
$$
UPDATE...ERVIN
SYNOPSIS...08
SHORT TERM...08
LONG TERM...05
AVIATION...08
AREA FORECAST DISCUSSION
NWS QUAD CITIES IA IL
740 AM CST SUN DEC 29 2013
.UPDATE...
ISSUED AT 726 AM CST SUN DEC 29 2013
BASED ON RADAR DUAL POL DATA IN CONCERT WITH WEAK VISIBILITY
RESTRICTIONS FROM THE LIGHT PRECIPITATION...HAVE ADDED PATCHY
FREEZING DRIZZLE THROUGH MID MORNING TO THE FORECAST.
IF THE TRENDS IN THE RAP ARE CORRECT...THE CURRENT FORCING MOVING
THROUGH THE AREA WITH DRIER AIR ALOFT IS PRODUCING SOME LIGHT SNOW
MIXED WITH VERY LIGHT FREEZING DRIZZLE. THIS SHALLOW MOISTURE
SHOULD EXIT THE AREA SHORTLY AFTER MID MORNING.
ACROSS CENTRAL IOWA...THERE IS ANOTHER AREA OF FORCING BUT THE
MOISTURE IS A BIT DEEPER BASED ON CONDENSATION PRESSURE DEFICITS.
HERE PRECIPITATION IS STILL LIGHT BUT OBSERVATIONS AND RADAR DATA
SUGGEST MORE FLURRIES OR VERY LIGHT SNOW INSTEAD OF FREEZING DRIZZLE.
REGARDING THE CURRENT HEADLINES...THE COLDER AIR IS NOT MOVING IN
AS FAST AS THE SHORT RANGE MODEL TRENDS HAVE BEEN SUGGESTING. THIS
OBSERVATIONAL TREND BRINGS QUESTIONS AS TO WHETHER OR NOT 15 BELOW
ZERO IS ACHIEVABLE TONIGHT IN AREAS WEST OF A DUBUQUE TO IOWA CITY
LINE. IF THIS IS THE CASE...THEN WIND CHILLS WOULD NOT PROBABLY
NOT EXCEED 30 BELOW ZERO EITHER. THIS AREA IS RIGHT ON THE CUSP
BETWEEN AN ADVISORY AND A WARNING FOR WIND CHILL. TRENDS THROUGH
THE DAY WILL BE CRITICAL IN DETERMINING WHICH WAY THE HEADLINE
WILL EVENTUALLY GO FOR TONIGHT.
UPDATE ISSUED AT 532 AM CST SUN DEC 29 2013
TEMPERATURES ARE FALLING BUT NOT NEARLY AS FAST AS PREVIOUSLY
THOUGHT. OVERNIGHT LOWS ARE STILL EXPECTED 7-9 AM WITH HIGHS 8-10
AM THAT ARE ONLY 1-2 DEGREES ABOVE THE OVERNIGHT LOWS.
TEMPERATURES ARE THEN EXPECTED TO SLOWLY FALL THROUGH THE DAY.
RADAR AND VISIBILITY TRENDS ARE SUGGESTING THE CURRENT VERY LIGHT
PRECIPITATION WILL BE MOVING EAST OF THE MISSISSIPPI THIS MORNING
WITH POSSIBLY SOME FLURRIES. BASED ON DATA FROM THE 12Z
SOUNDING...VERY LIGHT FREEZING DRIZZLE CANNOT BE RULED OUT EITHER.
ALTHOUGH PAVEMENT TEMPERATURES ARE GENERALLY AT OR BELOW
FREEZING...THE STRONG WIND IS PROMOTING EVAPORATION WHICH MAY
LIMIT OR REDUCE ANY FREEZING DRIZZLE ACCUMULATION ON ROADS.
&&
.SYNOPSIS...
ISSUED AT 317 AM CST SUN DEC 29 2013
06Z SFC ANALYSIS HAD A LOW IN CENTRAL WISCONSIN WITH A WEAK TROF
RUNNING FROM THE LOW INTO NORTHEAST MISSOURI. THE ARCTIC FRONT RAN
FROM WESTERN UPPER MICHIGAN...TO KANSAS CITY... AND THEN TO AROUND
KAMA. DEW POINTS ALONG AND AHEAD OF THE ARCTIC FRONT WERE IN THE
20S AND 30S WITH TEENS AND COLDER BEHIND THE FRONT INTO THE PLAINS.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 317 AM CST SUN DEC 29 2013
THE ARCTIC FRONT IS GENERALLY ALONG THE MISSISSIPPI AT 09Z AND
SHOULD BE OVER THE FAR EASTERN AREAS BY SUNRISE. WINDS JUMP
QUICKLY BEHIND THE FRONT WITH SUSTAINED WINDS OF 15 TO 25 MPH WITH
GUSTS OVER 30 MPH. LOW TEMPERATURES THIS MORNING WILL OCCUR 7-9 AM
WITH MAX TEMPERATURES IN THE 8-10 AM TIME FRAME. AT BEST MOST OF
THE AREA WILL ONLY SEEN A 1-2 DEGREE RISE BEFORE TEMPERATURES
START FALLING THROUGH THE DAY.
MOISTURE IN THE LOWER ATMOSPHERE IS NOT AS GREAT AS ORIGINALLY
SUGGESTED. THUS MAINLY FLURRIES WILL BE SEEN DURING THE DAY WITH
SOME AREAS OF LIGHT SNOW. AT BEST ANY ACCUMULATION WOULD BE A DUSTING.
THE CURRENT WIND CHILL ADVISORY HAS BEEN DELAYED UNTIL LATE
MORNING BASED ON EXPECTED TEMPERATURES AND WINDS.
TONIGHT...DRY CONDITIONS ARE EXPECTED AS THE NEXT ARCTIC HIGH
BUILDS INTO THE MIDWEST. BASED ON PROJECTED LOWS AND WIND...AREAS
GENERALLY EAST OF THE CURRENT WIND CHILL ADVISORY WILL MET WIND
CHILL CRITERIA TONIGHT INTO MONDAY MORNING.
AREAS WEST OF A DUBUQUE TO IOWA CITY LINE MAY SEE WIND CHILLS
EXCEED 30 BELOW TONIGHT BEFORE THE ARRIVAL OF THE ARCTIC HIGH. IF
THIS OCCURS...THEN A WIND CHILL WARNING WOULD BE NEEDED FOR THAT
AREA. HOWEVER...TEMPERATURES MAY NOT DROP OFF AS QUICKLY AS
FORECAST AND WINDS MAY NOT BE AS STRONG WHICH WOULD RESULT IN WIND
CHILLS OF ONLY 30 BELOW ZERO. THIS SITUATION WILL HAVE TO BE MONITORED
CAREFULLY DURING THE DAY IN CASE THE ADVISORY WOULD NEED TO BE UPGRADED.
.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 317 AM CST SUN DEC 29 2013
SNOWIER PATTERN APPEARS IN STORE FOR THE AREA THROUGHOUT THE
EXTENDED AS SEVERAL CLIPPER SYSTEMS ARE SHUTTLED DOWN
OVER THE REGION IN ACTIVE NORTHWEST FLOW.
TEMPS THROUGHOUT THE PERIOD TO REMAIN WELL BELOW NORMAL IN
THE NORTHWEST FLOW. CHALLENGE IN TIME WILL BE IMPACT
OF NEGATIVE FEEDBACK FROM FRESH NEW SNOW COVER ON TEMPS.
IF SOME AREAS SEE 2-5+ INCHES OF NEW SNOW AS IS LOOKING
QUITE REASONABLE AT THIS TIME THEN GOING TEMPS ESPECIALLY
OVER THE LATTER HALF OF THE PERIOD WILL LIKELY NEED TO BE
LOWERED.
FIRST ROUND OF ACCUMULATING SNOW ANTICIPATED MON AFTN/EVE
ESPECIALLY ACROSS THE NORTH 1/2 TO POSSIBLY 2/3RDS OF CWA WITH
CLIPPER SYSTEM AND ATTENDANT WARM ADVECTION. LIQUID PCPN
AMOUNTS LOOK TO BE LIGHT AND LESS THAN 0.1 INCH BUT HIGH SNOW
TO LIQUID RATIOS OF 15-20+:1 SUPPORTIVE OF AN INCH OR TWO
OF ACCUMULATION WITH THE HIGHER AMOUNTS FAVORING AREAS NORTH
OF I-80.
ANOTHER CLIPPER SYSTEM THEN FOLLOWS ABOUT 24+ HRS LATER OR LATE
TUE AFTN/NGT WITH SIMILAR LIGHT QPF AND HIGH RATIO EVENT
FOR ANOTHER INCH OR POSSIBLY TWO OF SNOW ESPECIALLY NEAR TO
NORTH OF I-80.
MODELS ARE THEN COMING INTO BETTER AGREEMENT ON A MUCH STRONGER
SYSTEM FOR WED/WED NGT. BETTER MOISTURE AND GOOD DYNAMICS IN
TERMS OF DIGGING SHORTWAVE AND COUPLED UPPER JET STRUCTURE
SUGGESTIVE OF MODERATE QPF EVENT OF 0.25-0.4 INCH POSSIBLE WHICH
WITH SNOW TO LIQUID RATIOS OF 13-17:1 WOULD RESULT IN 3-6 INCH
POTENTIAL SNOW ACCUMS. STILL WAY EARLY IN THE GAME AND OF COURSE
A LOT OF UNCERTAINTY WITH TRACK... BUT THE MAGNITUDE OF FORCING
AND MOISTURE WILL MAKE THIS ONE TO WATCH IN THE COMING DAYS.
MODELS THEN SUGGEST POTENTIAL OF A QUITE PERIOD LATE WEEK AND
INTO NEXT WEEKEND AS THE FLOW PATTERN APPEARS SET TO UNDERGO
TRANSITION TO SOUTHWESTERLY FLOW BY EARLY NEXT WEEK. LATEST RUNS
OF GFS AND ECMWF THEN SHOW AN EVEN STRONGER SYSTEM EJECTING FROM
THE SOUTHWEST AND THROUGH THE CENTRAL CONUS EARLY NEXT WEEK WHICH
COULD BRING MORE SNOW OR A WINTRY MIX TO THE REGION.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z MONDAY MORNING)
ISSUED AT 532 AM CST SUN DEC 29 2013
VERY LIGHT PRECIPITATION...IN THE FORM OF FLURRIES OR POSSIBLY
FZDZ...IS OCCURRING ACROSS IOWA AND NORTHERN ILLINOIS BEHIND THE
ARCTIC FRONT. PRESENT WEATHER SENSORS ON OBSERVATIONS ARE NOT
PICKING UP THE LIGHT PRECIPITATION BUT VISIBILITY SENSORS ARE BY
INDICATING A REDUCTION BELOW 10SM. SO...IFR TO LIFR CONDITIONS
WITH VCSH WILL SLOWLY IMPROVE TO MVFR AND THEN VFR THROUGH 00Z/30.
ARCTIC HIGH PRESSURE BUILDING INTO THE MIDWEST AFT 00Z/30 WILL
RESULT IN VFR CONDITIONS AND WINDS DROPPING UNDER 10 KNOTS.
&&
.DVN WATCHES/WARNINGS/ADVISORIES...
IA...WIND CHILL ADVISORY FROM 5 PM THIS AFTERNOON TO NOON CST MONDAY
FOR CLINTON-HENRY IA-JACKSON-LOUISA-MUSCATINE-SCOTT.
WIND CHILL ADVISORY UNTIL NOON CST MONDAY FOR BENTON-BUCHANAN-
CEDAR-DELAWARE-DUBUQUE-IOWA-JEFFERSON-JOHNSON-JONES-KEOKUK-
LINN-WASHINGTON.
IL...WIND CHILL ADVISORY FROM 5 PM THIS AFTERNOON TO NOON CST MONDAY
FOR BUREAU-CARROLL-HENRY IL-JO DAVIESS-MERCER-PUTNAM-ROCK
ISLAND-STEPHENSON-WHITESIDE.
MO...NONE.
&&
$$
UPDATE...08
SYNOPSIS...08
SHORT TERM...08
LONG TERM...05
AVIATION...08
AREA FORECAST DISCUSSION
NWS GRAY ME
1048 AM EST SUN DEC 29 2013
.SYNOPSIS...
A COLD FRONT WILL BECOME STATIONARY OVER SOUTHERN PORTIONS OF
MAINE AND NEW HAMPSHIRE THIS MORNING. LOW PRESSURE WILL REACH THE
MID ATLANTIC COASTLINE THIS AFTERNOON...BEFORE PASSING OVER CAPE
COD THIS EVENING AND THROUGH THE GULF OF MAINE TONIGHT. HIGH
PRESSURE WILL BUILD INTO THE REGION MONDAY...WITH A WEAK WEATHER
DISTURBANCE CROSSING THE WATERS ON TUESDAY. LOW PRESSURE WILL
GRADUALLY APPROACH THE EAST ON WEDNESDAY...BEFORE INTENSIFYING OFF
THE MID ATLANTIC COAST ON THURSDAY.
&&
.NEAR TERM /TODAY/...
LATE MORNING UPDATE...
HAVE PERFORMED A MAJOR REWORK OF THE FORECAST FOR TODAY AND
TONIGHT PRIMARILY TO IMPROVE CONSISTENCY IN THE FORECAST AND
HEADLINES. TEMPERATURES TODAY ARE A LITTLE COOLER THAN EXPECTED...
AND THE COLD FRONT HAS NOW PUSHED SOUTH THROUGH BANGOR. HRRR AND
NAM MODELS WHICH ARE SOME OF THE HIGHER RESOLUTION MODELS
AVAILABLE... NOW SHOW A COLDER FORECAST DURING THE EVENT LATER
TODAY AND TONIGHT... RESULTING IN A QUICKER TRANSITION TO SNOW FOR
SOME AREAS. HAVE TRENDED TOWARD THIS IDEA... THOUGH STILL MAINTAIN
THAT COASTAL AREAS WILL LIKELY SEE MORE RAIN THAN SNOW. SNOW WILL
BE A HEAVY... STICKY... WET SNOW AND MAY CAUSE ADDITIONAL PROBLEMS
DUE TO THE WEIGHT OF THIS SNOW ON TREES. SNOWFALL RATES COULD BE 1
TO 2 INCHES PER HOUR... OR EVEN HIGHER AT TIMES. INTENSE SNOWFALL
RATES COULD ACTUALLY BE ENOUGH TO FORCE THE CHANGE OVER FROM RAIN
TO SNOW FOR MORE AREAS. SNOW BEGINS TO REACH SOUTHERN AREAS BY
AROUND 4 PM... WITH THE HEAVIEST SNOW FALLING FROM 6 PM TO
MIDNIGHT. HAVE EXPANDED THE WINTER STORM WARNINGS TO INCLUDE MORE
AREAS OF SOUTHERN AND WESTERN NEW HAMPSHIRE WHERE THE HEAVIER BAND
SHOULD SET UP LATER TODAY. THERE COULD BE A SHARP DROP OFF IN SNOW
TOTALS ON THE NORTHERN EDGE ALSO... WITH FAR NORTHERN AREAS
POSSIBLY SEEING LESS THAN 4 INCHES.
EARLY MORNING UPDATE...
HAVE UPDATED GRIDS BASED ON CURRENT CONDITIONS. BACKDOOR COLD
FRONT CONTINUES TO PRESS SOUTH AND WEST TOWARDS OUR AREA. THIS
FRONT SHOULD SLOW DOWN OVER THE NEXT FEW HOURS. CLOUDS WILL
CONTINUE TO INCREASE AND THICKEN THIS MORNING. PRECIPITATION TO
OVERSPREAD THE REGION LATER THIS AFTERNOON AND EARLY THIS EVENING.
ORIGINAL DISCUSSION...
CLOUDS WILL CONTINUE TO INCREASE AND THICKEN TODAY FROM
SOUTH TO NORTH...WITH PATCHY FOG EARLY. AT THE SAME TIME...A
BACKDOOR COLD FRONT WILL ALLOW ARCTIC AIR TO POUR INTO NORTHERN
MAINE. THIS COLD AIR WILL SETTLE SOUTHWARD...AS THE FRONT STALLS
OVER SOUTHERN SECTIONS THIS AFTERNOON AS THE PRECIPITATION...JUST
AS THE NEXT SYSTEM ENTERS THE REGION. THE PRECIPITATION WILL
LIKELY BEGIN AS LIGHT RAIN OVER SOUTHERN AREAS LATE THIS AFTERNOON
IN A NEARLY ISOTHERMAL ATMOSPHERIC LAYERS.
USED A BLEND OF WRMEMS/SREF AND NAM12 FOR DAYTIME MAXES.
&&
.SHORT TERM /TONIGHT AND MONDAY/...
VERY INTERESTING SITUATION WILL UNFOLD EARLY THIS EVENING AS
VERTICAL MOTIONS INCREASE RAPIDLY AHEAD OF COASTAL LOW NEAR LONG
ISLAND NEW YORK. A DEGREE OR TWO EITHER WAY IN OUR LOW LEVEL
SOUNDINGS WILL HAVE SIGNIFICANT RAMIFICATIONS OVER SOUTHERN
AREAS. TIMING AND PENETRATION OF ARCTIC AIR WILL REMAIN CRITICAL
AS WELL. USED A BLEND OF MODEL GUIDANCE AND CONCEPTUAL MODEL OF
THIS FAST PACED EVENT...WILL ALLOW FOR LITTLE IN THE WAY OF
SNOWFALL ALONG THE IMMEDIATE SHORELINE AS MUCH OF THE PRECIP WILL
FALL IN THE FORM OF RAIN. HOWEVER...THERE WILL BE A SHARP GRADIENT
AS YOU HEAD JUST 10-20 MILES NORTH AWAY FROM THE COASTLINE...WHERE
MAINLY SNOW WILL FALL...AND A TIMES AT FAST CLIP RATES UP TO AN
INCH+ PER HOUR WITHIN THE NEARLY ISOTHERMAL LAYER.
WILL CONTINUE WINTER WEATHER ADVISORIES FOR THE COASTLINE (YORK
COUNTY NORTHWARD) AND WINTER STORM WARNINGS ADJACENT TO THESE
COUNTIES. THESE HEADLINES MAY NEED TO BE TWEAKED DURING THE DAY.
WILL ALSO CONTINUE TO HAVE WINTER WEATHER ADVISORIES IN THE NORTH
AND MOUNTAINS WHICH SHOULD PICK UP 3-6 INCHES OF NEW SNOW. HAVE
INCLUDED NORTHERN COOS COUNTY INTO THE ADVISORIES FOR EASTERN
PORTIONS OF THE COUNTY. WESTERN PORTIONS LIKELY TO HAVE
DOWNSLOPE CONDITIONS DURING THIS EVENT. WAS CONSIDERING EXPANDING
THE WINTER WEATHER ADVISORIES TO INCLUDE NORTHERNMOST PORTIONS OF
INTERIOR ROCKINGHAM COUNTY...BUT WILL OMIT FOR NOW AND LET THE DAY
SHIFT FURTHER EVALUATE.
WITH LITTLE OR NO WRAP AROUND PRECIPITATION WITH THIS SYSTEM...THE
PRECIPITATION QUICKLY COMES TO A HALT AROUND OR SHORTLY AFTER
MIDNIGHT.
ON MONDAY...ARCTIC AIR POURS INTO THE REGION ON GUSTY WINDS
FOLLOWING THE DEPARTING SURFACE LOW. THERE MAY BE A SQUALL OR TWO
IN THE MOUNTAINS WITH THIS SHARP BOUNDARY.
&&
.LONG TERM /MONDAY NIGHT THROUGH SATURDAY/...
THE LATEST AVAILABLE NUMERICALS ARE IN GOOD AGREEMENT ON LONGWAVE
PATTERN THROUGH LATE NEXT WEEK. IT WILL BE TURNING COLDER WITH
WELL BELOW NORMAL TEMPERATURES FOR MUCH OF THE PERIOD...AS THE
POLAR VORTEX INITIALLY CENTERED NORTH OF HUDSON BAY SETTLES SLOWLY
SOUTHEAST INTO QUEBEC PROVINCE. WE BEGIN THE PERIOD WITH A WEAK
IMPULSE AND ASSOCIATED SURFACE LOW CROSSING THE AREA LATE TUESDAY...
ACCOMPANIED BY A FEW CLOUDS AND SNOW SHOWERS. HIGH PRESSURE AND A
REINFORCING SHOT OF ARCTIC AIR FOLLOWS FOR MIDWEEK. THE NEXT
IMPULSE BRINGS A STRENGTHENING SURFACE LOW JUST TO OUR SOUTH
THURSDAY NIGHT INTO FRIDAY WITH ECMWF AND GFS OFFERING SOME
DIFFERENCES IN BOTH TIMING AND INTENSITY...WITH BOTH SUPPORTING AT
LEAST A MODERATE SNOWFALL TO THE REGION. ANOTHER AREA OF HIGH
PRESSURE FOLLOWS FOR FRIDAY NIGHT AND SATURDAY.
&&
.AVIATION /16Z SUNDAY THROUGH THURSDAY/...
SHORT TERM...AREAS OF LIFR CONDITIONS EARLY THIS MORNING IN LOW
CLOUDS AND FOG. CONDITIONS IMPROVING DURING THE MORNING...HOWEVER
CIGS/VSBYS LOWERING ONCE AGAIN TO IFR AND LIFR IN MIXED RAIN AND
SNOW LATE TODAY AND TONIGHT. VFR CONDITIONS EXPECTED ON MONDAY.
LONG TERM...
TUE PM - WED AM...SCT MVFR IN SNOW SHOWERS.
WESTERLY SFC WND GUSTING TO 25 KT.
THU NIGHT - FRI...MVFR WITH AREAS OF IFR IN SNOW.
GUSTY SFC WND TO 25 KT POSSIBLE NR COAST.
&&
.MARINE...
SHORT TERM...HAVE ISSUED GALE WARNINGS FOR THE OUTER WATERS AS THE
NEXT COASTAL LOW INTENSIFIES AND APPROACHES FROM THE SOUTH. SCAS
ISSUED FOR THE BAYS.
LONG TERM...
TUE...SMALL CRAFT CONDITIONS ARE LIKELY.
WED - THU...GALE FORCE WINDS ARE LIKELY.
&&
.GYX WATCHES/WARNINGS/ADVISORIES...
ME...WINTER STORM WARNING FROM 4 PM THIS AFTERNOON TO 6 AM EST
MONDAY FOR MEZ012>014-018>022-028.
WINTER WEATHER ADVISORY FROM 4 PM THIS AFTERNOON TO 6 AM EST
MONDAY FOR MEZ007>009-023>027.
NH...WINTER STORM WARNING FROM 4 PM THIS AFTERNOON TO 6 AM EST
MONDAY FOR NHZ004>006-008>010.
WINTER WEATHER ADVISORY FROM 4 PM THIS AFTERNOON TO 6 AM EST
MONDAY FOR NHZ001>003.
WINTER WEATHER ADVISORY FROM 4 PM THIS AFTERNOON TO 4 AM EST
MONDAY FOR NHZ007-013.
MARINE...SMALL CRAFT ADVISORY FROM 6 PM THIS EVENING TO 6 PM EST MONDAY
FOR ANZ151-153.
GALE WARNING FROM 6 PM THIS EVENING TO 6 PM EST MONDAY FOR
ANZ150-152-154.
&&
$$
NEAR TERM UPDATE... KIMBLE
AREA FORECAST DISCUSSION
NWS BUFFALO NY
951 AM EST SUN DEC 29 2013
.SYNOPSIS...
LOW PRESSURE MOVING UP THE EAST COAST WILL BRING SOME RAIN TO OUR
AREA THIS AFTERNOON. THE RAIN COULD MIX WITH SNOW ACROSS THE HIGHER
ELEVATIONS OF THE SOUTHERN TIER. AS THE LOW PULLS AWAY FROM THE NEW
ENGLAND COAST TONIGHT...A NORTHWEST OF MUCH COLDER AIR WILL SURGE
ACROSS THE LOWER LAKES AND GENERATE SOME LAKE EFFECT SNOW SHOWERS.
ANOTHER LOW WILL BRING A GENERAL SNOWFALL...AND SOME LAKE ENHANCED
SNOW...LATE MONDAY NIGHT INTO TUESDAY. VERY COLD AIR THAT FOLLOWS
THIS LOW WILL LAST THROUGH THE END OF NEXT WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
AT 930 AM...RADAR SHOWS PRECIPITATION SPREADING INTO NORTHERN
PENNSYLVANIA...WITH THIS LIKELY TO REACH THE NY BORDER IN THE
NEXT HOUR. THIS AREA WILL CONTINUE TO SPREAD NORTHWARD THROUGH
MID-AFTERNOON...AND THEN START RETREATING TO THE EAST LATE
AFTERNOON. THE 12Z NAM AND RUNS OF THE HRRR SHOW ONLY A MODEST
SHIFT IN GUIDANCE. THE BIGGEST DIFFERENCE IS THAT THE WESTERN CUT-
OFF OF THE PRECIPITATION SHOULD BE JUST SLIGHTLY TO THE
EAST...WHICH INCREASES THE CHANCE BUFFALO AND AREAS NORTH AND WEST
WILL STAY DRY TODAY. IN FACT...THE BACK EDGE OF THE PRECIPITATION
SHIELD WILL LIKELY BE NEAR A BUF-ART LINE...HOWEVER STILL MAINTAIN
A HIGH CONFIDENCE IN MEASURABLE PRECIPITATION SE OF THIS WHICH
INCLUDES THE VAST MAJORITY OF THE CWA.
THE MODELS AGREE THAT THIS LOW WILL STRENGTHEN AS IT LIFTS
NORTHEAST AND REACHES THE VICINITY OF LONG ISLAND BY THIS EVENING.
THIS PROJECTED PATH OF THE LOW NORMALLY DOES NOT BRING MUCH
PRECIPITATION TO OUR REGION. AND THIS WILL LIKELY BE THE CASE
TODAY WITH THE MAIN LIFT ASSOCIATED WITH THE POTENT LOW LEVEL
EXPECTED TO STAY ALONG THE EAST COAST. HOWEVER...A BROAD SCALE
CYCLONIC FLOW WILL BE IN PLACE OVER NEW YORK STATE...WHILE A
PASSING UPPER LEVEL JET STREAK GENERATES ADDITIONAL LARGE SCALE
LIFT. AS A RESULT...STILL HAVE CONFIDENCE THAT MEASURABLE
PRECIPITATION WILL FALL ACROSS MOST OF THE CWA...EVEN IF IT WILL
BE RELATIVELY LIGHT.
STEADIEST PRECIPITATION WILL BE ACROSS CENTRAL NEW YORK...WITH
BETWEEN TWO AND FOUR TENTHS OF AN INCH OF QPF SOUTHEAST OF ELZ-
FZY. HOWEVER...THERE IS STILL A CONCERN THAT AS THE RAIN BECOME
MORE STEADY ACROSS THE SOUTHERN TIER THIS AFTERNOON...THE HIGHER
ELEVATIONS SHOULD SEE A CHANGEOVER TO SNOW AS THE BOUNDARY LAYER
COOLS FROM EVAPORATIONAL COOLING. THIS WILL RESULT IN AN
ISOTHERMAL LAYER CENTERED AROUND 0C...WITH AN 1 TO 3 INCHES OF WET
SNOW EXPECTED AT ELEVATIONS ABOVE 1600-1800 FEET. A SIMILAR STORY MAY
PLAY OUT ACROSS PORTIONS OF LEWIS COUNTY...AGAIN DEPENDING ON
ELEVATION.
AS THE MAIN LOW PULLS AWAY FROM THE NEW ENGLAND COAST THIS
EVENING...THE ARCTIC FRONT THAT IS ASSOCIATED WITH THE SOUTHERN
QUEBEC LOW WILL PUSH EAST ACROSS WESTERN AND CENTRAL NEW YORK. THIS
WILL CAUSE ANY LINGERING PCPN TO CHANGE OVER TO SNOW. SNOW
ACCUMULATIONS SHOULD BE MINIMAL THIS EVENING SINCE THE STEADIEST
PCPN ASSOCIATED WITH THE DEPARTING LOW WILL BE GONE BY THE TIME THE
COLDER AIR ARRIVES.
A NORTHWEST FLOW OF COLDER AIR WILL SET UP ACROSS THE LOWER LAKES
DURING THE SECOND HALF OF THE NIGHT. THIS WILL RESULT IN SOME LAKE
EFFECT SNOW SOUTHEAST OF THE LAKES. ACCUMULATIONS TONIGHT SHOULD
REMAIN BELOW ADVISORY CRITERIA SINCE THE DEEPER SYNOPTIC MOISTURE
ASSOCIATED WITH THE LOW WILL BE GONE.
REGARDING TEMPERATURES...TODAY`S RELATIVELY MILD READINGS WILL GIVE
WAY TO MUCH COLDER CONDITIONS TONIGHT AS TEMPERATURES FALL INTO THE
TEENS/LOWER 20S BY DAYBREAK MONDAY.
&&
.SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/...
850MB TEMPS DROP TO AROUND -16C BY MONDAY MORNING...PLENTY COLD
ENOUGH TO SUPPORT A LAKE RESPONSE UNDER NW FLOW. THE AIRMASS WILL BE
RAPIDLY DRYING OUT HOWEVER AS SURFACE HIGH PRESSURE AND SUBSIDENCE
QUICKLY BUILDS TOWARDS THE LOWER LAKES. THE DRY BACKGROUND SYNOPTIC
SCALE ENVIRONMENT WILL GREATLY LIMIT THE STRENGTH OF THE LAKE
RESPONSE...WITH JUST LIGHT SNOW SHOWERS EXPECTED SOUTHEAST OF THE
LAKES. THIS MAY PRODUCE AN INCH OR TWO IN SOME SPOTS ALONG THE
CHAUTAUQUA RIDGE OFF LAKE ERIE AND FROM WAYNE TO OSWEGO COUNTIES OFF
LAKE ONTARIO DURING THE MORNING. THE LAKE EFFECT WILL SLOWLY
DIMINISH TO SCATTERED FLURRIES AND LIGHT SNOW SHOWERS BY AFTERNOON.
OUTSIDE OF LAKE EFFECT AREAS ANY LINGERING FLURRIES OR LIGHT SNOW
SHOWERS IN THE MORNING WILL GRADUALLY END WITH SOME BREAKS OF
SUNSHINE DEVELOPING LATER IN THE DAY. HIGHS WILL ONLY BE IN THE
UPPER TEENS IN MOST AREAS...WITH LOWER TEENS ACROSS THE NORTH
COUNTRY.
HIGH PRESSURE BRIEFLY BUILDS OVER THE LOWER LAKES MONDAY EVENING.
THIS WILL BRING AN END TO THE LAKE EFFECT AS ANY SNOW SHOWERS LEFT
WILL RETRACT BACK OVER THE LAKE AND TEA KETTLE AS THE LOW LEVEL FLOW
BECOMES LIGHT AND LAND BREEZE CIRCULATIONS TAKE OVER. LOWS WILL DROP
INTO THE LOWER TEENS OR HIGH SINGLE DIGITS ACROSS WESTERN NY AND A
LITTLE BELOW ZERO EAST OF LAKE ONTARIO. THESE LOWS WILL LIKELY OCCUR
EARLY...WITH INCREASING CLOUDS AND MIXING DEVELOPING LATER AHEAD OF
A FAST MOVING CLIPPER.
THE CLIPPER LOW AND ASSOCIATED MID LEVEL SHORTWAVE WILL PASS BY JUST
NORTH OF THE REGION ON TUESDAY. THIS WILL PRODUCE SOME LIGHT SNOW
ACROSS MOST AREAS WITH AN INITIAL PUSH OF WARM ADVECTION PROVIDING
ISENTROPIC ASCENT...FOLLOWED BY DPVA JUST AHEAD OF THE MID LEVEL
SHORTWAVE SUPPORTING A FEW MORE SNOW SHOWERS. OUTSIDE OF LAKE EFFECT
AREAS AMOUNTS WILL BE LIGHT...WITH A COATING TO AN INCH ACCUMULATION.
THE AIRMASS IS COLD ENOUGH AHEAD OF THE CLIPPER TO SUPPORT A LAKE
RESPONSE...AND INSTABILITY WILL IMPROVE NEAR THE TIME OF THE PASSAGE
OF THE MID LEVEL SHORTWAVE AND SURFACE COLD FRONT. LAKE INDUCED
EQUILIBRIUM LEVELS WILL RISE TO AROUND 10K FEET AT THIS TIME OFF
BOTH LAKES WITH MODERATE INSTABILITY DEVELOPING. BOUNDARY LAYER FLOW
WILL INITIALLY BE SHEARED AHEAD OF THE CLIPPER...BUT NAM AND GFS
BUFKIT PROFILES SHOW WINDS BECOMING BETTER ALIGNED ALONG AND JUST
BEHIND THE SURFACE COLD FRONTAL PASSAGE. PAST EXPERIENCE SHOWS THIS
TYPE OF SYSTEM IS OFTEN ACCOMPANIED BY A BURST OF LAKE ENHANCED SNOW
ALONG THE COLD FRONT OF THE CLIPPER...AND SOME OF THE HIGHER
RESOLUTION MODEL GUIDANCE IS SUGGESTING THAT WITH THIS FEATURE. THIS
MAY PRODUCE SEVERAL INCHES OF ACCUMULATION ACROSS THE NIAGARA
FRONTIER BEFORE PUSHING QUICKLY SOUTH INTO THE SOUTHERN TIER BY THE
END OF THE DAY. A SIMILAR TREND IS EXPECTED EAST OF LAKE ONTARIO A
FEW HOURS LATER.
FOLLOWING THE LAKE ENHANCEMENT WITH THE CLIPPER...EXPECT MORE PURE
LAKE EFFECT TO CONTINUE LATER TUESDAY AFTERNOON AND TUESDAY NIGHT.
BANDS SHOULD REMAIN MOBILE HOWEVER WITH BOUNDARY LAYER FLOW VEERING
TO WEST AND EVENTUALLY NORTHWEST OVERNIGHT AS AN ARCTIC COLD FRONT
SAGS SLOWLY SOUTH ACROSS THE LOWER LAKES. THIS WILL LIKELY FORCE THE
LAKE ONTARIO BAND SOUTH AND ONSHORE ALONG MUCH OF THE SOUTH SHORE
WITH A BURST OF SNOW BEFORE BREAKING APART INTO MULTIPLE WEAK BANDS
LATE BEHIND THE ARCTIC BOUNDARY.
&&
.LONG TERM /WEDNESDAY THROUGH SATURDAY/...
VERY COLD AIR WILL DOMINATE THE LONG TERM PERIOD WITH THE POTENTIAL
FOR ACCUMULATING SNOW AS WELL LATE THIS WEEK.
THE ARCTIC VORTEX WILL TAKE A SWING ACROSS HUDSON BAY AND INTO
QUEBEC ON WEDNESDAY AND FORCE A VERY COLD AIRMASS SOUTH INTO THE
GREAT LAKES AND NORTHEAST. THE NORTH COUNTRY SHOULD GET INTO THE DRY
ARCTIC AIRMASS BEHIND THIS FRONT ON WEDNESDAY AND REMAIN DRY...WITH
A CHANCE OF A LITTLE LIGHT SNOW ACROSS WESTERN AND CENTRAL NY ALONG
THE BOUNDARY AND DUE TO A LITTLE WEAK NORTHERLY FLOW LAKE EFFECT.
MODEL GUIDANCE HAS MADE SOME SIGNIFICANT ADJUSTMENTS OVER THE PAST
24 HOURS FOR THE THURSDAY AND FRIDAY TIME FRAME. LATEST 00Z GFS AND
ECMWF OPERATIONAL SOLUTIONS ARE MUCH FARTHER NORTH AND DEEPER WITH A
MID LEVEL SHORTWAVE AND SURFACE LOW. IF THIS WERE TO VERIFY IT WOULD
PRODUCE A LONG DURATION ACCUMULATING SNOW WEDNESDAY NIGHT THROUGH
FRIDAY ACROSS THE ENTIRE AREA...WITH LAKE ENHANCEMENT SOUTH OF LAKE
ONTARIO ON THE TAIL END FRIDAY.
THESE SAME OPERATIONAL MODELS YESTERDAY SHOWED THIS SYSTEM
SUPPRESSED WELL SOUTH ACROSS THE SOUTHEAST STATES WITH GENERALLY
COLD AND DRY WEATHER IN OUR REGION. LATEST 00Z GEFS ENSEMBLE MEMBERS
STILL SHOW A WIDE RANGE OF SOLUTIONS...WITH SOME SUPPORT FOR THE
OPERATIONAL GFS AND ECMWF SOLUTIONS...WHILE OTHER MEMBERS SHOW THE
LOWER LAKES DRY WITH A FAR SOUTHERLY SOLUTION. USING THE PRESSURE ON
THE 1.5 PVU SURFACE AS A TRACER...THE ENERGY THAT MAY PRODUCE THIS
SYSTEM IS CURRENTLY JUST SOUTHWEST OF THE ALEUTIAN ISLANDS WHILE
ANOTHER PIECE OF THE PUZZLE IS COMING ACROSS THE TOP OF THE WORLD IN
CROSS POLAR FLOW. GIVEN BOTH OF THESE SYSTEMS ARE SO FAR AWAY AND IN
DATA SPARSE REGIONS... THE CURRENT MODEL SOLUTIONS FOR THURSDAY AND
FRIDAY SHOULD BE CONSIDERED LOW CONFIDENCE EVEN WITH GOOD AGREEMENT
AT THE MOMENT. WITH THIS IN MIND...HAVE JUST INCREASED POPS INTO THE
MID CHANCE RANGE FOR THE PERIOD. IF MODEL GUIDANCE TOMORROW REMAINS
CONSISTENT...MORE CONFIDENCE IN THE SCENARIO WILL EXIST.
TEMPERATURES WILL REMAIN COLD THURSDAY AND FRIDAY REGARDLESS OF
WHETHER THE SYSTEM VERIFIES OR NOT. LOWS WILL AT LEAST BE IN THE
SINGLE NUMBERS WITH HIGHS IN THE TEENS ACROSS MOST OF THE AREA WITH
SOME POTENTIAL FOR EVEN COLDER READINGS. ACROSS THE NORTH COUNTRY
SINGLE DIGIT HIGHS ARE LIKELY WITH LOWS WELL BELOW ZERO. EXACTLY HOW
COLD IT GETS ON SOME OF THESE NIGHTS WILL DEPEND ON THE TRACK AND
TIMING OF SURFACE HIGHS...AND WHETHER SKIES CAN CLEAR OUT OR NOT. IF
THEY DO...TEMPERATURES MAY FREE FALL.
&&
.AVIATION /15Z SUNDAY THROUGH THURSDAY/...
LOW PRESSURE OVER THE SOUTHEAST STATES WILL MOVE TO THE NORTHEAST
AND REACH LONG ISLAND BY THIS EVENING. LIGHT RAIN DEVELOPING WELL
AHEAD OF THIS SYSTEM WILL MOVE INTO THE SOUTHERN TIER THIS
MORNING...THEN SPREAD NORTH ACROSS THE REST OF THE AREA THIS
AFTERNOON. THE RAIN MAY MIX WITH OR CHANGE TO SNOW ACROSS THE HIGHER
ELEVATIONS OF THE SOUTHERN TIER....BUT SHOULD STAY ALL RAIN AT TAF SITES.
VFR CLOUDS WILL LOWER THROUGHOUT THE MORNING. AS THE RAIN BECOME
MORE WIDESPREAD THIS AFTERNOON...THE LOWER LEVELS WILL
MOISTEN...CAUSING CIGS TO DETERIORATE TO MVFR. WHERE THE RAIN MIXES
WITH SNOW LATER THIS AFTERNOON AND EVENING...IFR CONDITIONS ARE
LIKELY.
AFTER THE LOW PULLS AWAY FROM THE NEW ENGLAND COAST THIS
EVENING...THE STEADIER PCPN WILL TAPER OFF FROM WEST TO EAST. COLDER
AIR FOLLOWING THE LOW WILL CHANGE ANY REMAINING PCPN TO SNOW.
MAINLY MVFR CONDITIONS WILL PREVAIL...EXCEPT EAST AND SOUTHEAST OF
THE LAKES WHERE STEADIER SNOW WILL RESULT IN IFR CONDITIONS AT
TIMES.
OUTLOOK...
MONDAY AND TUESDAY...VFR/MVFR WITH A CHANCE OF SNOW SHOWERS.
LOCAL IFR IN LAKE EFFECT SNOW SHOWERS EAST AND SOUTHEAST OF THE
LAKES.
WEDNESDAY AND THURSDAY...VFR/MVFR WITH A CHANCE OF SNOW
SHOWERS.
&&
.MARINE...
WINDS HAVE RELAXED ACROSS THE LAKES EARLY THIS MORNING.
HOWEVER...ANOTHER ROUND OF SMALL CRAFT ADVISORY CONDITIONS WILL
DEVELOP TONIGHT INTO MONDAY MORNING AS COLD AIR RUSHES BACK INTO THE
LOWER LAKES ON MODERATE TO STRONG NORTHWEST WINDS.
&&
.BUF WATCHES/WARNINGS/ADVISORIES...
NY...NONE.
MARINE...SMALL CRAFT ADVISORY FROM 7 PM THIS EVENING TO 10 AM EST
MONDAY FOR LEZ020-040-041.
SMALL CRAFT ADVISORY FROM 7 PM THIS EVENING TO 10 AM
EST MONDAY FOR LOZ030.
SMALL CRAFT ADVISORY FROM 10 PM THIS EVENING TO 10 PM EST
MONDAY FOR LOZ043>045.
SMALL CRAFT ADVISORY FROM 7 PM THIS EVENING TO 4 PM EST
MONDAY FOR LOZ042.
&&
$$
SYNOPSIS...TJP
NEAR TERM...APFFEL/TJP
SHORT TERM...HITCHCOCK
LONG TERM...HITCHCOCK
AVIATION...APFFEL/TJP
MARINE...APFFEL/TJP
AREA FORECAST DISCUSSION
NWS RALEIGH NC
710 AM EST SUN DEC 29 2013
.SYNOPSIS...A LOW PRESSURE SYSTEM WILL TRACK ACROSS THE AREA
TODAY...FOLLOWED BY THE ATTENDANT COLD FRONT SUNDAY NIGHT. ANOTHER
UPPER LEVEL DISTURBANCE WILL CROSS THE REGION MONDAY NIGHT.
&&
.NEAR TERM /THROUGH TODAY/...
AS OF 250 AM SUNDAY...
AN UPPER LOW OVER THE LOWER MISSISSIPPI RIVER VALLEY WILL CONTINUE
TO LIFT NORTHEAST TODAY...DEAMPLIFYING AS IT BECOMES INCREASINGLY
NEGATIVELY TILTED. THE ASSOCIATED DCVA AND 50-60 LOW LEVEL JET WILL
DEEPEN AND ACCELERATE A SURFACE LOW...CURRENTLY DEVELOPING OVER THE
FLORIDA PANHANDLE...TOWARD THE DELMARVA AREA TODAY.
NOT A LOT OF CHANGES TO MAKE TO THE CURRENT FORECAST. AREAS OF
LIGHT RAIN OVER SPREADING THE AREA ARE CREATING AN IN-SITU COLD AIR
DAMMING AIRMASS AND STRENGTHENING THE STABILITY ACROSS THE CWA.
MODELS HAVE TRENDED A LITTLE EAST WITH THE TRACK OF THE SURFACE
LOW...ESPECIALLY THE GFS...THOUGH NOT AS MUCH AS ONE MIGHT EXPECT IF
THEY ARE CATCHING ONTO THE CAD AIRMASS. A CONSENSUS WOULD TRACK THE
LOW UP THE I-95 CORRIDOR BETWEEN 15Z AND 18Z. THE COASTAL WARM
FRONT AND 55-65F DEWPOINT AIR ALONG THE CAROLINA COAST WILL SURGE
INLAND AS PRESSURES BEGIN TO FALL...BUT IT APPEARS THE BETTER
MARITIME AIRMASS THAT WOULD LEAD TO BETTER DESTABILIZATION AND
SEVERE THREAT WILL STAY ALONG THE COAST...HINDERED BY THE STABLE CAD
AIRMASS. STILL..THERE MAY BE A BRIEF PERIOD (15-18Z) WHERE 250-500
J/KG OF NEAR SURFACE BASED CAPE CAN PHASE WITH HODOGRAPHS FAVORABLE
OF LOW-TOPPED ROTATING STORMS OVER THE COASTAL PLAIN. ON THE HEELS
OF THE SURFACE LOW...A BROKEN LINE OF SHOWERS SHOULD DEVELOP ALONG
THE WEAK COLD FRONT AND CONVERGENCE ZONE...WHICH COULD STILL PRODUCE
SOME STRONG WIND GUSTS VIA DOWNWARD MOMENTUM TRANSPORT ON THE TAIL
END OF THE LOW LEVEL JET.
CATEGORICAL POPS DURING THE FIRST HALF OF THE DAY WILL TREND DOWN
QUICKLY FROM SOUTHWEST TO NORTHEAST AFTER 18Z AND THE CWA WILL BE
COMPLETELY DRY BY 00Z. HARD TO GET A SOLID HANDLE ON QPF AMOUNTS AS
PRECIP IS JUST NOW BEGINNING TO FILL IN ACROSS THE CWA. THE FOCI
FOR HEAVIER PRECIP WILL BE THE LLJ ENHANCED ISENTROPIC ACCENT OVER
THE CAD COLD DOME IN THE WEST AND ALSO THE SURFACE LOW/FRONTAL
PRECIP BAND OVER THE COASTAL PLAIN. HOURLY RAINFALL RATES UPSTREAM
ARE AROUND 0.10" TO 0.25"...WHICH AGREE WELL WITH THE RAP AND HRRR.
BASED ON THIS...A WIDESPREAD 1-1.5" STILL SEEMS REASONABLE.
REGARDING TEMPS...THE CWA WILL BE SPLIT BY THE INLAND PUSH OF THE
WARM SECTOR...WITH MID AND UPPER 40S OVER THE WESTERN PIEDMONT AND
UPPER 50S TO POSSIBLE MID 60S OVER THE COASTAL PLAIN. THERE IS A
CHANCE THAT WESTERLY WIND AND PARTIAL CLEARING BEHIND THE FRONT MAY
ALLOW TEMPS IN THE TRIAD TO JUMP A COUPLE EXTRA DEGREES BEFORE
SUNSET.
&&
.SHORT TERM /SUNDAY NIGHT THROUGH MONDAY NIGHT/...
AS OF 300 AM SUNDAY...
IN THE WAKE OF THE DEPARTING LOW PRESSURE SYSTEM...LOW LEVEL
MOISTURE WILL SLOWLY SCOUR VIA A WESTERLY WIND SUNDAY EVENING/NIGHT.
CIRRUS SHOULD SPREAD BACK IN FROM THE SOUTHWEST OVERNIGHT AND DURING
THE DAY MONDAY AHEAD OF A WAVE MOVING THROUGH THE MEAN UPPER TROUGH.
A WEAKENING MSLP GRADIENT AND AT LEAST PARTIAL CLEARING MAY LEAD TO
FOG POTENTIAL...THOUGH CONFIDENCE IN THIS IS LOW AT THE MOMENT.
LOWS 36-41. HIGHS MONDAY 49-56. -SMITH
MONDAY NIGHT:
THE PASSAGE OF THE MID/UPPER LEVEL TROUGH AND EMBEDDED
VIGOROUS SHORTWAVE WILL BRING AN INCREASE IN CLOUDS WITH SOME LIGHT
PRECIP DEVELOPING OVER THE AREA BETWEEN 06 TO 12Z TUESDAY IN
RESPONSE TO LOW AND MID-LEVEL FGEN UNDERNEATH RENEWED UPPER-LEVEL
DIVERGENCE WITHIN THE RIGHT ENTRANCE REGION OF A 150 JET CENTERED
OVER THE MID-ATLANTIC SEABOARD. THE GFS AND NAM EVEN SPIN UP A WEAK
SFC WAVE ALONG THE LINGERING FRONTAL BOUNDARY OFF THE NC COAST. THE
ECWMF WHICH HAD BEEN A DRY OUTLIER...HAS NOW JUMPED ON BOARD...WITH
AVERAGE QPF AMOUNTS OF 0.03 TO 0.06" ACROSS THE AREA.
FCST SOUNDINGS ARE MUCH WARMER IN THE BOUNDARY LAYER AND SATURATION
IS MUCH SHALLOWER...WITH NO SEEDING OF ICE FROM ABOVE GIVEN CLOUD
SEPARATION OF AROUND 10KFT. THUS HAVE REMOVED ANY MENTION OF SNOW
WITH JUST RAIN. LOWS IN THE MID 30S NW TO UPPER 30S/NEAR 40 SE.
&&
.LONG TERM /TUESDAY THROUGH SATURDAY/...
AS OF 300 AM SUNDAY...
TUESDAY AND WEDNESDAY:
UNDERNEATH ZONAL FLOW ALOFT...EXPECT DRY CONDITIONS WITH
TEMPERATURES AT OR JUST BELOW NORMAL AS THE MODIFIED CANADIAN HIGH
BUILDS EASTWARD OVER THE AREA.
THURSDAY THROUGH SATURDAY:
THERE REMAINS CONSIDERABLE UNCERTAINTY AND LARGE MODEL SPREAD AMONG
THE DETERMINISTIC MODEL GUIDANCE AND ENSEMBLES WITH RESPECT TO THE
UPSTREAM AMPLIFICATION/TIMING OF A NORTHERN STREAM WAVE DROPPING
SEWD THROUGH THE BASE OF THE MEAN TROUGH AND RESULTANT DOWNSTREAM
MILLER-B TYPE CYCLOGENESIS ALONG THE MID-ATLANTIC COAST. THE ECWMF
CONTINUES TO BE ON THE DEEPER/SLOWER SIDE OF GUIDANCE...BUT EVEN IT
HAS BACKED WITH PRECIP ACROSS THE AREA FOR WITH VERY LITTLE TO NO
SOUTHERN STREAM MOISTURE LINKAGE. MEANWHILE...THE QUICKER/MORE
PROGRESSIVE GFS REMAINS DRY. WILL HAVE TO CONTINUE MONITOR THIS
SYSTEM...PARTICULARLY THE TIMING AND JUST HOW CLOSE TO THE COAST THE
SYSTEM WILL DEVELOP. WILL KEEPS POPS IN THE SLGT CHC FOR THURSDAY
WITH FRIDAY DRY AS EVEN THE SLOWER EC HAS US DRY SLOTTED BY THEN.
OTHERWISE...TEMPS WILL GENERALLY BE NEAR OR SLIGHTLY BELOW NORMAL
THURSDAY DEPENDING ON PRECIP CHANCES...THEN WELL BELOW NORMAL BEHIND
THE SYSTEM ON FRIDAY AND INTO THE FIRST PART OF THE WEEKEND AS
ANOTHER ARCTIC HIGH BUILDS EASTWARD INTO THE REGION
&&
.AVIATION /12Z SUNDAY THROUGH THURSDAY/...
AS OF 710 AM SUNDAY...
A LOW PRESSURE SYSTEM WILL LIFT NORTHEAST ACROSS THE REGION
TODAY...WITH ADVERSE AVIATION CONDITIONS TO CONTINUE THROUGH THIS
AFTERNOON. WIDESPREAD MODERATE RAIN MOVING ACROSS CENTRAL NC WILL
MAINTAIN THE IFR AND LIFR CEILINGS THIS MORNING. MEANWHILE...AN
INTENSE SOUTHERLY LOW LEVEL JET IS CURRENTLY SURGING ACROSS THE AREA
AND CREATING A THREAT OF LOW LEVEL WIND SHEAR. LATER THIS MORNING
(BETWEEN ROUGHLY 15Z AND 18Z)...THE AFOREMENTIONED LOW WILL MOVE
ACROSS EASTERN NC...AT WHICH TIME WINDS WILL BEGIN TO VEER AROUND TO
SOUTHWESTERLY. CEILINGS SHOULD BEGIN TO SCATTER AND LIFT OVER THE
COASTAL PLAIN...POSSIBLY REACHING MVFR BY AROUND 16-17Z. WINDS WILL
INCREASE TO AROUND 15MPH AND MAY GUSTS TO 25-30MPH IN HEAVIER
SHOWERS. THERE IS STILL A SMALL CHANCE OF AN ISOLATED THUNDERSTORMS
FROM KFAY TO KRWI. ONCE THE LOW MOVES OFF TO THE NORTHEAST...A COLD
FRONT WILL SWEEP ACROSS THE AREA AND SCOUR THE REMAIN LOW LEVEL
MOISTURE....WITH VFR CONDITIONS TO RETURN BY 21-00Z WITH A LIGHT
WESTERLY WIND. IF SKIES REMAIN CLEAR TONIGHT AND WINDS ARE WEAK
ENOUGH... THERE MAY ENOUGH LOW LEVEL MOISTURE FOR PATCHY
FOG...MAINLY ACROSS THE SANDHILLS AND SOUTHERN COASTAL PLAIN.
LOOKING AHEAD: ANOTHER UPPER LEVEL DISTURBANCE WILL CROSS THE AREA
MONDAY NIGHT...WHICH MAY CREATE ISOLATED SHOWERS AND A BRIEF PERIOD
OF SUB-VFR CONDITIONS. VFR CONDITIONS ARE THEN EXPECTED THROUGH
WEDNESDAY...WITH ANOTHER CHANCE OF RAIN BY THURSDAY.
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...SMITH
NEAR TERM...SMITH
SHORT TERM...SMITH/CBL
LONG TERM...CBL
AVIATION...SMITH
AREA FORECAST DISCUSSION
NWS BISMARCK ND
859 AM CST SUN DEC 29 2013
.UPDATE...
ISSUED AT 900 AM CST SUN DEC 29 2013
CLOUDS ACROSS WESTERN ND HAVE REMAINED IN PLACE WITH TEMPERATURES
AROUND ZERO AND WIND CHILL VALUES ABOVE ADVISORY CRITERIA...SO
HAVE CANCELLED WIND CHILL ADVISORY FOR THIS AREA. WIND CHILLS
IMMEDIATELY EAST OF CLOUDS REMAIN IN ADVISORY/WARNING RANGE AND
HAVE CONTINUED THE HEADLINES THERE. OTHERWISE...FORECAST REMAINS
ON TRACK.
UPDATE ISSUED AT 639 AM CST SUN DEC 29 2013
MID LEVEL CLOUDS OVER WESTERN NORTH DAKOTA THIS MORNING MORE
EXPANSIVE THAN MODELS FORECAST AT 700MB....BUT MOISTURE AT H850 IN
MODELS...JUST NOT SHOWING UP AT THAT LEVEL. KEPT CLOUDS IN FORECAST
WEST INTO CENTRAL. ALTHOUGH WIND CHILLS JUST A BIT OUT OF CATEGORY
WEST ANY BUT OF WIND WILL LOWER INTO CATEGORY.
UPDATE
ISSUED AT 550 AM CST SUN DEC 29 2013
QUICK UPDATE TO ACCOUNT FOR LINGERING LARGE AREA OF BKN-OVC CIGS
ACROSS WESTERN NORTH DAKOTA. AS MENTIONED BELOW...MODELS ARE
POORLY DEPICTING THESE CLOUDS...WHICH GREATLY AFFECT THIS MORNINGS
TEMPERATURES FORECAST. THE LATEST RAP APPEARS TO HINT AT THESE
CLOUDS...WHICH HOLD TOGETHER WELL INTO THIS MORNING. THUS
INCREASED SKY COVER WEST AND WARMED TEMPERATURES NEAR TO
UNDERNEATH THE CLOUDS. STILL COLD WHERE SKIES HAVE GONE
CLEAR...AROUND 25 BELOW AND PERHAPS COLDER WITH DEWPOINTS NEARING
30 BELOW.
&&
.SHORT TERM...(THIS MORNING THROUGH TONIGHT)
ISSUED AT 411 AM CST SUN DEC 29 2013
FORECAST HIGHLIGHTS IN THE SHORT TERM PERIOD WILL BE VERY COLD
TEMPERATURES THIS MORNING AND AFTERNOON...FOLLOWED BY A SHOT OF
LIGHT ACCUMULATING SNOW FOR TONIGHT.
CURRENTLY...ARCTIC HIGH PRESSURE CONTINUES SOUTH INTO NORTH
DAKOTA EARLY THIS MORNING...RESULTING IN A RAPIDLY CLEARING SKY
ACROSS MY NORTH CENTRAL SPREADING SOUTHWARD. MODELS FAILED TO PICK
UP ON A RATHER LARGE AREA OF 4-5K FOOT AGL CIGS FROM FAR SOUTH
CENTRAL SASKATCHEWAN EXTENDING SOUTHEAST INTO NORTHWESTERN NORTH
DAKOTA. IT IS UNCLEAR IF THESE CLOUDS WILL CLEAR OUT AT ALL WITH
RETURN FLOW DEVELOPING AFTER 12Z THIS MORNING AND INCREASING
CLOUDS EXPECTED FROM THE WEST. BUFFER SOUNDINGS DO SHOW A GRADUAL
SCATTERING OUT AFTER SUNRISE AS THE TOP OF THE CLOUD LAYER
DE-SATURATES DOWNWARD...SO DID TREND SKY COVER FOR THIS AREA TO
SCATTERED/MOSTLY SUNNY 12-15Z THIS MORNING.
AS THE SKY CLEARS AND WINDS CONTINUE TO SUBSIDE UNDERNEATH THE
ARCTIC HIGH...TEMPERATURES WILL RAPIDLY PLUMMET. ALREADY NEAR 15
BELOW OVER MY FAR NORTH CENTRAL...AND EXPECT LOWS OF 20 BELOW TO
NEAR 25 BELOW ZERO ACROSS PORTIONS OF CENTRAL NORTH DAKOTA THROUGH
8-9AM SUNDAY. WARMER SOUTHWEST AROUND 5 BELOW WHERE LINGERING
CLOUDS ARE FORECAST. WIND CHILL HEADLINES LOOK FINE AND WILL MAKE
NO CHANGES WITH THIS FORECAST ISSUANCE.
COLD START OF THE DAY WILL RESULT IN SUBZERO HIGHS OVER MY CENTRAL
(NEAR -5F) AND MY EAST (NEAR -10F). BETTER SOUTHERLY RETURN FLOW
AND WAA ACROSS MY SOUTHWEST WHERE WE HAVE FORECAST HIGHS AROUND
10F ABOVE ZERO.
ACTIVE WEATHER PATTERN CONTINUES AS ANOTHER CLIPPER TRACKS
SOUTHEAST ACROSS THE NORTHERN PLAINS TONIGHT. UPPER LEVEL 125KT
JET STREAK NOW RIDING OVER THE UPPER LEVEL RIDGE PARKED OFF THE
WEST COAST WILL MOVE SOUTHEAST TONIGHT TO OVER THE NORTHERN HIGH
PLAINS OF MT/WY. THIS FEATURE WILL DRIVE A MID LEVEL IMPULSE AND
ASSOCIATED SURFACE LOW FROM EASTERN MONTANA THIS EVENING
SOUTHEAST INTO CENTRAL SOUTH DAKOTA AFTER MIDNIGHT. THE TRACK OF
THIS LOW AND PLACEMENT OF UPPER LEVEL DIVERGENCE WILL FAVOR
PRECIPITATION DEVELOPING ACROSS THE NORTHWEST THIS EVENING...THEN
SPREADING EAST-SOUTHEAST LATE SUNDAY NIGHT ACROSS CENTRAL ND AND
EVENTUALLY INTO THE JAMES RIVER BASIN AND SOUTHERN RED RIVER
VALLEY MONDAY MORNING. THANKS TO SNOW RATIOS RANGING FROM 15:1 TO
20:1...MAY SEE IN INCH TO AN INCH AND ONE HALF OF SNOW BY MONDAY
MORNING ALONG THE ABOVE MENTIONED TRACK...ROUGHLY ACROSS THE
NORTHWEST QUARTER OF THE STATE SOUTHEAST THROUGH MINOT AND
BISMARCK AND THROUGH THE JAMES RIVER BASIN.
WHILE WINDS WILL TRANSITION TO NORTH/NORTHWEST BEHIND THIS
CLIPPER AND INCREASE SOME...GRADIENT FORCING AND PRESSURE RISES
RATHER WEAK SO AM NOT ANTICIPATING MUCH BLOWING SNOW POTENTIAL AT
THIS TIME.
ONE MORE THING OF NOTE...EXPECT TEMPERATURES TO WARM THIS EVENING
ESPECIALLY SOUTHWEST INTO SOUTH CENTRAL WHERE THE BEST WAA WILL
OCCUR TONIGHT AHEAD OF THE LOW BEFORE CAA OVERTAKES US FOR MONDAY
DAYTIME. THUS EXPECT TO SEE TODAYS HIGH TEMPERATURES REACHED MANY
LOCATIONS SOMETIME THIS SUNDAY EVENING...AND MONDAYS HIGHS MOST
LIKELY SOMETIME AFTER MIDNIGHT THROUGH MONDAY MORNING.
.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 411 AM CST SUN DEC 29 2013
MODELS CONTINUE THE TREND OF A COLD UPPER LOW OVER CENTRAL CANADA
REMAINING QUASI STATIONARY...ALBEIT MEANDERING A BIT...DURING THE
EXTENDED FORECAST PERIOD. AT THE SAME TIME...EASTERN PACIFIC RIDGING
REMAINS IN PLACE FEEDING MILDER TEMPERATURES TO THE WESTERN US.
ACROSS THE NORTHERN PLAINS...THE BATTLE BETWEEN THE WARM AND COLD
WILL BRING AN ACTIVE WEATHER PATTERN TO THE REGION. TUESDAY AND
WEDNESDAY MORNINGS SHOULD REMAIN QUITE COLD...WITH LOWS AS COLD AS
THE MID 20S BELOW ACROSS THE NORTH CENTRAL. COLD WIND CHILLS WILL
AGAIN BE FEATURED AT THIS TIME ESPECIALLY ALONG THE CANADIAN BORDER.
THEN A SHORTWAVE WILL MOVE ACROSS THE NORTHERN PLAINS AND BRING A
CHANCE OF SNOW THROUGH THE FIRST HALF OF THE PERIOD. ACCUMULATING
SNOW APPEARS LIKELY TUESDAY AND WEDNESDAY. AFTER WEDNESDAY...THE
ARCTIC AIR GETS NUDGED BACK NORTH AND MODERATING TEMPERATURES...
ESPECIALLY BY FRIDAY AND SATURDAY MAKE THERE WAY BACK TO NORTH
DAKOTA.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z MONDAY MORNING)
ISSUED AT 639 AM CST SUN DEC 29 2013
BKN-OVC MID LEVEL CLOUDS WILL PERSIST THROUGH SUNDAY MORNING AND
WEST AND DRIFT SLOWLY EASTWARD INTO THE CENTRAL ASSOCIATED WITH
WEAK WARM ADVECTION IMPACTING KISN-KDIK-KMOT-KBIS. OVERALL...VFR
FLIGHT CONDITIONS EXPECTED THROUGH SUNDAY AFTERNOON. ANOTHER
CLIPPER STORM SYSTEM WILL MOVE SOUTHEAST INTO THE DAKOTAS SUNDAY
EVENING OVERNIGHT INTO MONDAY MORNING. EXPECT TO SEE DETERIORATING
FLIGHT CONDITIONS WEST SUNDAY EVENING IMPACTING KISN AND
KDIK...THEN EASTWARD LATER SUNDAY NIGHT IMPACTING KBIS-KMOT- KJMS.
CIGS ARE FORECAST TO DROP TO MVFR AND VIS IN FALLING SNOW FALLING
TO IFR AND POSSIBLY LOWER.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
WIND CHILL ADVISORY UNTIL 1 PM CST THIS AFTERNOON FOR NDZ021-035-
046.
WIND CHILL WARNING UNTIL 1 PM CST THIS AFTERNOON FOR NDZ003>005-
011>013-022-023-025-036-037-047-048-050-051.
&&
$$
UPDATE...JNS
SHORT TERM...NH
LONG TERM...WAA
AVIATION...WAA
AREA FORECAST DISCUSSION
NWS BISMARCK ND
647 AM CST SUN DEC 29 2013
.UPDATE...
ISSUED AT 639 AM CST SUN DEC 29 2013
MID LEVEL CLOUDS OVER WESTERN NORTH DAKOTA THIS MORNING MORE
EXPANSIVE THAN MODELS FORECAST AT 700MB....BUT MOISTURE AT H850 IN
MODELS...JUST NOT SHOWING UP AT THAT LEVEL. KEPT CLOUDS IN FORECAST
WEST INTO CENTRAL. ALTHOUGH WIND CHILLS JUST A BIT OUT OF CATEGORY
WEST ANY BUT OF WIND WILL LOWER INTO CATEGORY.
UPDATE
ISSUED AT 550 AM CST SUN DEC 29 2013
QUICK UPDATE TO ACCOUNT FOR LINGERING LARGE AREA OF BKN-OVC CIGS
ACROSS WESTERN NORTH DAKOTA. AS MENTIONED BELOW...MODELS ARE
POORLY DEPICTING THESE CLOUDS...WHICH GREATLY AFFECT THIS MORNINGS
TEMPERATURES FORECAST. THE LATEST RAP APPEARS TO HINT AT THESE
CLOUDS...WHICH HOLD TOGETHER WELL INTO THIS MORNING. THUS
INCREASED SKY COVER WEST AND WARMED TEMPERATURES NEAR TO
UNDERNEATH THE CLOUDS. STILL COLD WHERE SKIES HAVE GONE
CLEAR...AROUND 25 BELOW AND PERHAPS COLDER WITH DEWPOINTS NEARING
30 BELOW.
&&
.SHORT TERM...(THIS MORNING THROUGH TONIGHT)
ISSUED AT 411 AM CST SUN DEC 29 2013
FORECAST HIGHLIGHTS IN THE SHORT TERM PERIOD WILL BE VERY COLD
TEMPERATURES THIS MORNING AND AFTERNOON...FOLLOWED BY A SHOT OF
LIGHT ACCUMULATING SNOW FOR TONIGHT.
CURRENTLY...ARCTIC HIGH PRESSURE CONTINUES SOUTH INTO NORTH
DAKOTA EARLY THIS MORNING...RESULTING IN A RAPIDLY CLEARING SKY
ACROSS MY NORTH CENTRAL SPREADING SOUTHWARD. MODELS FAILED TO PICK
UP ON A RATHER LARGE AREA OF 4-5K FOOT AGL CIGS FROM FAR SOUTH
CENTRAL SASKATCHEWAN EXTENDING SOUTHEAST INTO NORTHWESTERN NORTH
DAKOTA. IT IS UNCLEAR IF THESE CLOUDS WILL CLEAR OUT AT ALL WITH
RETURN FLOW DEVELOPING AFTER 12Z THIS MORNING AND INCREASING
CLOUDS EXPECTED FROM THE WEST. BUFFER SOUNDINGS DO SHOW A GRADUAL
SCATTERING OUT AFTER SUNRISE AS THE TOP OF THE CLOUD LAYER
DE-SATURATES DOWNWARD...SO DID TREND SKY COVER FOR THIS AREA TO
SCATTERED/MOSTLY SUNNY 12-15Z THIS MORNING.
AS THE SKY CLEARS AND WINDS CONTINUE TO SUBSIDE UNDERNEATH THE
ARCTIC HIGH...TEMPERATURES WILL RAPIDLY PLUMMET. ALREADY NEAR 15
BELOW OVER MY FAR NORTH CENTRAL...AND EXPECT LOWS OF 20 BELOW TO
NEAR 25 BELOW ZERO ACROSS PORTIONS OF CENTRAL NORTH DAKOTA THROUGH
8-9AM SUNDAY. WARMER SOUTHWEST AROUND 5 BELOW WHERE LINGERING
CLOUDS ARE FORECAST. WIND CHILL HEADLINES LOOK FINE AND WILL MAKE
NO CHANGES WITH THIS FORECAST ISSUANCE.
COLD START OF THE DAY WILL RESULT IN SUBZERO HIGHS OVER MY CENTRAL
(NEAR -5F) AND MY EAST (NEAR -10F). BETTER SOUTHERLY RETURN FLOW
AND WAA ACROSS MY SOUTHWEST WHERE WE HAVE FORECAST HIGHS AROUND
10F ABOVE ZERO.
ACTIVE WEATHER PATTERN CONTINUES AS ANOTHER CLIPPER TRACKS
SOUTHEAST ACROSS THE NORTHERN PLAINS TONIGHT. UPPER LEVEL 125KT
JET STREAK NOW RIDING OVER THE UPPER LEVEL RIDGE PARKED OFF THE
WEST COAST WILL MOVE SOUTHEAST TONIGHT TO OVER THE NORTHERN HIGH
PLAINS OF MT/WY. THIS FEATURE WILL DRIVE A MID LEVEL IMPULSE AND
ASSOCIATED SURFACE LOW FROM EASTERN MONTANA THIS EVENING
SOUTHEAST INTO CENTRAL SOUTH DAKOTA AFTER MIDNIGHT. THE TRACK OF
THIS LOW AND PLACEMENT OF UPPER LEVEL DIVERGENCE WILL FAVOR
PRECIPITATION DEVELOPING ACROSS THE NORTHWEST THIS EVENING...THEN
SPREADING EAST-SOUTHEAST LATE SUNDAY NIGHT ACROSS CENTRAL ND AND
EVENTUALLY INTO THE JAMES RIVER BASIN AND SOUTHERN RED RIVER
VALLEY MONDAY MORNING. THANKS TO SNOW RATIOS RANGING FROM 15:1 TO
20:1...MAY SEE IN INCH TO AN INCH AND ONE HALF OF SNOW BY MONDAY
MORNING ALONG THE ABOVE MENTIONED TRACK...ROUGHLY ACROSS THE
NORTHWEST QUARTER OF THE STATE SOUTHEAST THROUGH MINOT AND
BISMARCK AND THROUGH THE JAMES RIVER BASIN.
WHILE WINDS WILL TRANSITION TO NORTH/NORTHWEST BEHIND THIS
CLIPPER AND INCREASE SOME...GRADIENT FORCING AND PRESSURE RISES
RATHER WEAK SO AM NOT ANTICIPATING MUCH BLOWING SNOW POTENTIAL AT
THIS TIME.
ONE MORE THING OF NOTE...EXPECT TEMPERATURES TO WARM THIS EVENING
ESPECIALLY SOUTHWEST INTO SOUTH CENTRAL WHERE THE BEST WAA WILL
OCCUR TONIGHT AHEAD OF THE LOW BEFORE CAA OVERTAKES US FOR MONDAY
DAYTIME. THUS EXPECT TO SEE TODAYS HIGH TEMPERATURES REACHED MANY
LOCATIONS SOMETIME THIS SUNDAY EVENING...AND MONDAYS HIGHS MOST
LIKELY SOMETIME AFTER MIDNIGHT THROUGH MONDAY MORNING.
.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 411 AM CST SUN DEC 29 2013
MODELS CONTINUE THE TREND OF A COLD UPPER LOW OVER CENTRAL CANADA
REMAINING QUASI STATIONARY...ALBEIT MEANDERING A BIT...DURING THE
EXTENDED FORECAST PERIOD. AT THE SAME TIME...EASTERN PACIFIC RIDGING
REMAINS IN PLACE FEEDING MILDER TEMPERATURES TO THE WESTERN US.
ACROSS THE NORTHERN PLAINS...THE BATTLE BETWEEN THE WARM AND COLD
WILL BRING AN ACTIVE WEATHER PATTERN TO THE REGION. TUESDAY AND
WEDNESDAY MORNINGS SHOULD REMAIN QUITE COLD...WITH LOWS AS COLD AS
THE MID 20S BELOW ACROSS THE NORTH CENTRAL. COLD WIND CHILLS WILL
AGAIN BE FEATURED AT THIS TIME ESPECIALLY ALONG THE CANADIAN BORDER.
THEN A SHORTWAVE WILL MOVE ACROSS THE NORTHERN PLAINS AND BRING A
CHANCE OF SNOW THROUGH THE FIRST HALF OF THE PERIOD. ACCUMULATING
SNOW APPEARS LIKELY TUESDAY AND WEDNESDAY. AFTER WEDNESDAY...THE
ARCTIC AIR GETS NUDGED BACK NORTH AND MODERATING TEMPERATURES...
ESPECIALLY BY FRIDAY AND SATURDAY MAKE THERE WAY BACK TO NORTH
DAKOTA.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z MONDAY MORNING)
ISSUED AT 639 AM CST SUN DEC 29 2013
BKN-OVC MID LEVEL CLOUDS WILL PERSIST THROUGH SUNDAY MORNING AND
WEST AND DRIFT SLOWLY EASTWARD INTO THE CENTRAL ASSOCIATED WITH
WEAK WARM ADVECTION IMPACTING KISN-KDIK-KMOT-KBIS. OVERALL...VFR
FLIGHT CONDITIONS EXPECTED THROUGH SUNDAY AFTERNOON. ANOTHER
CLIPPER STORM SYSTEM WILL MOVE SOUTHEAST INTO THE DAKOTAS SUNDAY
EVENING OVERNIGHT INTO MONDAY MORNING. EXPECT TO SEE DETERIORATING
FLIGHT CONDITIONS WEST SUNDAY EVENING IMPACTING KISN AND
KDIK...THEN EASTWARD LATER SUNDAY NIGHT IMPACTING KBIS-KMOT- KJMS.
CIGS ARE FORECAST TO DROP TO MVFR AND VIS IN FALLING SNOW FALLING
TO IFR AND POSSIBLY LOWER.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
WIND CHILL ADVISORY UNTIL 1 PM CST /NOON MST/ THIS AFTERNOON FOR
NDZ001-009-010-017>021-031>035-040>046.
WIND CHILL WARNING UNTIL 1 PM CST THIS AFTERNOON FOR NDZ002>005-
011>013-022-023-025-036-037-047-048-050-051.
&&
$$
UPDATE...WAA
SHORT TERM...NH
LONG TERM...WAA
AVIATION...WAA
AREA FORECAST DISCUSSION
NWS BISMARCK ND
550 AM CST SUN DEC 29 2013
.UPDATE...
ISSUED AT 550 AM CST SUN DEC 29 2013
QUICK UPDATE TO ACCOUNT FOR LINGERING LARGE AREA OF BKN-OVC CIGS
ACROSS WESTERN NORTH DAKOTA. AS MENTIONED BELOW...MODELS ARE
POORLY DEPICTING THESE CLOUDS...WHICH GREATLY AFFECT THIS MORNINGS
TEMPERATURES FORECAST. THE LATEST RAP APPEARS TO HINT AT THESE
CLOUDS...WHICH HOLD TOGETHER WELL INTO THIS MORNING. THUS
INCREASED SKY COVER WEST AND WARMED TEMPERATURES NEAR TO
UNDERNEATH THE CLOUDS. STILL COLD WHERE SKIES HAVE GONE
CLEAR...AROUND 25 BELOW AND PERHAPS COLDER WITH DEWPOINTS NEARING
30 BELOW.
&&
.SHORT TERM...(THIS MORNING THROUGH TONIGHT)
ISSUED AT 411 AM CST SUN DEC 29 2013
FORECAST HIGHLIGHTS IN THE SHORT TERM PERIOD WILL BE VERY COLD
TEMPERATURES THIS MORNING AND AFTERNOON...FOLLOWED BY A SHOT OF
LIGHT ACCUMULATING SNOW FOR TONIGHT.
CURRENTLY...ARCTIC HIGH PRESSURE CONTINUES SOUTH INTO NORTH
DAKOTA EARLY THIS MORNING...RESULTING IN A RAPIDLY CLEARING SKY
ACROSS MY NORTH CENTRAL SPREADING SOUTHWARD. MODELS FAILED TO PICK
UP ON A RATHER LARGE AREA OF 4-5K FOOT AGL CIGS FROM FAR SOUTH
CENTRAL SASKATCHEWAN EXTENDING SOUTHEAST INTO NORTHWESTERN NORTH
DAKOTA. IT IS UNCLEAR IF THESE CLOUDS WILL CLEAR OUT AT ALL WITH
RETURN FLOW DEVELOPING AFTER 12Z THIS MORNING AND INCREASING
CLOUDS EXPECTED FROM THE WEST. BUFFER SOUNDINGS DO SHOW A GRADUAL
SCATTERING OUT AFTER SUNRISE AS THE TOP OF THE CLOUD LAYER
DE-SATURATES DOWNWARD...SO DID TREND SKY COVER FOR THIS AREA TO
SCATTERED/MOSTLY SUNNY 12-15Z THIS MORNING.
AS THE SKY CLEARS AND WINDS CONTINUE TO SUBSIDE UNDERNEATH THE
ARCTIC HIGH...TEMPERATURES WILL RAPIDLY PLUMMET. ALREADY NEAR 15
BELOW OVER MY FAR NORTH CENTRAL...AND EXPECT LOWS OF 20 BELOW TO
NEAR 25 BELOW ZERO ACROSS PORTIONS OF CENTRAL NORTH DAKOTA THROUGH
8-9AM SUNDAY. WARMER SOUTHWEST AROUND 5 BELOW WHERE LINGERING
CLOUDS ARE FORECAST. WIND CHILL HEADLINES LOOK FINE AND WILL MAKE
NO CHANGES WITH THIS FORECAST ISSUANCE.
COLD START OF THE DAY WILL RESULT IN SUBZERO HIGHS OVER MY CENTRAL
(NEAR -5F) AND MY EAST (NEAR -10F). BETTER SOUTHERLY RETURN FLOW
AND WAA ACROSS MY SOUTHWEST WHERE WE HAVE FORECAST HIGHS AROUND
10F ABOVE ZERO.
ACTIVE WEATHER PATTERN CONTINUES AS ANOTHER CLIPPER TRACKS
SOUTHEAST ACROSS THE NORTHERN PLAINS TONIGHT. UPPER LEVEL 125KT
JET STREAK NOW RIDING OVER THE UPPER LEVEL RIDGE PARKED OFF THE
WEST COAST WILL MOVE SOUTHEAST TONIGHT TO OVER THE NORTHERN HIGH
PLAINS OF MT/WY. THIS FEATURE WILL DRIVE A MID LEVEL IMPULSE AND
ASSOCIATED SURFACE LOW FROM EASTERN MONTANA THIS EVENING
SOUTHEAST INTO CENTRAL SOUTH DAKOTA AFTER MIDNIGHT. THE TRACK OF
THIS LOW AND PLACEMENT OF UPPER LEVEL DIVERGENCE WILL FAVOR
PRECIPITATION DEVELOPING ACROSS THE NORTHWEST THIS EVENING...THEN
SPREADING EAST-SOUTHEAST LATE SUNDAY NIGHT ACROSS CENTRAL ND AND
EVENTUALLY INTO THE JAMES RIVER BASIN AND SOUTHERN RED RIVER
VALLEY MONDAY MORNING. THANKS TO SNOW RATIOS RANGING FROM 15:1 TO
20:1...MAY SEE IN INCH TO AN INCH AND ONE HALF OF SNOW BY MONDAY
MORNING ALONG THE ABOVE MENTIONED TRACK...ROUGHLY ACROSS THE
NORTHWEST QUARTER OF THE STATE SOUTHEAST THROUGH MINOT AND
BISMARCK AND THROUGH THE JAMES RIVER BASIN.
WHILE WINDS WILL TRANSITION TO NORTH/NORTHWEST BEHIND THIS
CLIPPER AND INCREASE SOME...GRADIENT FORCING AND PRESSURE RISES
RATHER WEAK SO AM NOT ANTICIPATING MUCH BLOWING SNOW POTENTIAL AT
THIS TIME.
ONE MORE THING OF NOTE...EXPECT TEMPERATURES TO WARM THIS EVENING
ESPECIALLY SOUTHWEST INTO SOUTH CENTRAL WHERE THE BEST WAA WILL
OCCUR TONIGHT AHEAD OF THE LOW BEFORE CAA OVERTAKES US FOR MONDAY
DAYTIME. THUS EXPECT TO SEE TODAYS HIGH TEMPERATURES REACHED MANY
LOCATIONS SOMETIME THIS SUNDAY EVENING...AND MONDAYS HIGHS MOST
LIKELY SOMETIME AFTER MIDNIGHT THROUGH MONDAY MORNING.
.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 411 AM CST SUN DEC 29 2013
MODELS CONTINUE THE TREND OF A COLD UPPER LOW OVER CENTRAL CANADA
REMAINING QUASI STATIONARY...ALBEIT MEANDERING A BIT...DURING THE
EXTENDED FORECAST PERIOD. AT THE SAME TIME...EASTERN PACIFIC RIDGING
REMAINS IN PLACE FEEDING MILDER TEMPERATURES TO THE WESTERN US.
ACROSS THE NORTHERN PLAINS...THE BATTLE BETWEEN THE WARM AND COLD
WILL BRING AN ACTIVE WEATHER PATTERN TO THE REGION. TUESDAY AND
WEDNESDAY MORNINGS SHOULD REMAIN QUITE COLD...WITH LOWS AS COLD AS
THE MID 20S BELOW ACROSS THE NORTH CENTRAL. COLD WIND CHILLS WILL
AGAIN BE FEATURED AT THIS TIME ESPECIALLY ALONG THE CANADIAN BORDER.
THEN A SHORTWAVE WILL MOVE ACROSS THE NORTHERN PLAINS AND BRING A
CHANCE OF SNOW THROUGH THE FIRST HALF OF THE PERIOD. ACCUMULATING
SNOW APPEARS LIKELY TUESDAY AND WEDNESDAY. AFTER WEDNESDAY...THE
ARCTIC AIR GETS NUDGED BACK NORTH AND MODERATING TEMPERATURES...
ESPECIALLY BY FRIDAY AND SATURDAY MAKE THERE WAY BACK TO NORTH
DAKOTA.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z MONDAY MORNING)
ISSUED AT 550 AM CST SUN DEC 29 2013
BKN-OVC MID LEVEL CLOUDS WILL SLOWLY CLEAR NOW THROUGH 15Z CENTRAL
AND EAST AS SURFACE HIGH PRESSURE BUILDS ACROSS NORTH DAKOTA.
LINGERING BKN-OVC CIGS AROUND 5K FT AGL MAY LINGER THROUGH THE
MORNING ACROSS THE WEST...IMPACTING KISN-KDIK. OVERALL...VFR
FLIGHT CONDITIONS EXPECTED THROUGH SUNDAY AFTERNOON. ANOTHER
CLIPPER STORM SYSTEM WILL MOVE SOUTHEAST INTO THE DAKOTAS SUNDAY
EVENING OVERNIGHT INTO MONDAY MORNING. EXPECT TO SEE DETERIORATING
FLIGHT CONDITIONS WEST SUNDAY EVENING IMPACTING KISN AND
KDIK...THEN EASTWARD LATER SUNDAY NIGHT IMPACTING KBIS-KMOT- KJMS.
CIGS ARE FORECAST TO DROP TO MVFR AND VIS IN FALLING SNOW FALLING
TO IFR AND POSSIBLY LOWER.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
WIND CHILL ADVISORY UNTIL 1 PM CST /NOON MST/ THIS AFTERNOON FOR
NDZ001-009-010-017>021-031>035-040>046.
WIND CHILL WARNING UNTIL 1 PM CST THIS AFTERNOON FOR NDZ002>005-
011>013-022-023-025-036-037-047-048-050-051.
&&
$$
UPDATE...NH
SHORT TERM...NH
LONG TERM...WAA
AVIATION...NH
AREA FORECAST DISCUSSION
NWS CHARLESTON WV
747 AM EST SUN DEC 29 2013
.SYNOPSIS...
LOW PRESSURE MOVES UP THE EAST COAST TODAY. COLD FRONT LATE SUNDAY
NIGHT INTO MONDAY. HIGH PRESSURE TUESDAY. ANOTHER SYSTEM THURSDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
UPDATE...
FORECAST FOR MUCH OF TODAY IS GENERALLY ON TRACK. HOWEVER...
APPEARS CURRENT FORECAST HAS TEMPS FALLING MUCH FASTER THAN
CURRENT THINKING. HAVE NOT MADE WHOLESALE CHANGES...BUT HAVE MADE
SOME TWEAKS TO TEMPS AND CORRESPONDING WEATHER GRIDS TO REFLECT
CURRENT THINKING.
PREVIOUS DISCUSSION...
EXTENSIVE SHIELD OF RAIN HAS NOW OVERSPREAD THE AREA...AND SHOULD
CONTINUE TO ENCOMPASS MOST COUNTIES THROUGH 12Z TODAY. SURFACE LOW
PRESSURE BRINGING THE MOISTURE INTO THE CWA WILL RACE UP THE EAST
COAST. WILL START LOSING THE DEPTH OF THIS MOISTURE AFTER 18Z
TODAY...AND WILL REDUCE THE POPS ACCORDINGLY AS THE UPPER AND MID
LEVELS ACQUIRE DRIER AIR. STILL EXPECTING TOTALS TO TOP OUT IN THE
1 TO 1.25 INCH RANGE...LIKELY OVER SOUTHWEST VIRGINIA AND THE
SOUTHERN MOUNTAINS.
TIMING IS STILL IN GOOD AGREEMENT AMONGST THE MODELS...BUT HAVE
FOCUSED ON THE HIGH RESOLUTION HRRR AND WRF MODELS FOR THE TIMING IN
TERMS OF DECREASING THE POPS THROUGH THE AFTERNOON AND EVENING.
MEANWHILE...A COLD FRONT CURRENTLY PLOWING THROUGH THE NORTHERN
PLAINS USHERING A BITTERLY COLD ARCTIC AIRMASS. THIS COLD FRONT WILL
RAPIDLY PUSH THROUGH THE SOUTHERN GREAT LAKES...AND WILL REACH OUR
SOUTHEAST OHIO COUNTIES AFTER 00Z MONDAY. IT WILL NOT BE BRINGING
QUITE THE SAME AIR CURRENTLY FILLING IN BEHIND THE FRONT IN
MINNESOTA AND THE DAKOTAS...BUT IT WILL BE A SIGNIFICANT AIRMASS
CHANGE FOR THE MIDDLE OHIO VALLEY. CAN EXPECT A FEW SNOW SHOWERS
WITH THE FRONT...AND THEN NORTHWESTERLY FLOW IN PLUNGING 850MB
TEMPERATURE AIR BRINGING UPSLOPING SNOW CONDITIONS THAT WILL EXTEND
INTO THE SHORT TERM FORECAST PERIOD.
NOT EXPECTING MUCH IN TERMS OF TEMPERATURE RECOVERY TODAY IN THE
RAIN...WITH UPPER 30S TO LOWER 40S EXPECTED. BEHIND THE COLD
FRONT...LOW 20S WILL FIND THEIR WAY INTO THE SOUTHEAST OHIO COUNTIES
BY 12Z MONDAY.
&&
.SHORT TERM /MONDAY THROUGH WEDNESDAY NIGHT/...
THIS PERIOD WILL BE CHARACTERIZED BY FAST WEST TO NORTHWEST FLOW
ALOFT...WITH A DIGGING NORTHERN STREAM UPPER TROUGH OVER THE
MISSISSIPPI AND OHIO VALLEYS BY THURSDAY. OPERATIONAL MODELS ARE
STRONGLY TRENDING TOWARD THIS SCENARIO. IN THIS FAST FLOW...POST
COLD FRONTAL SNOW SHOWERS...MAINLY IN THE NORTHERN AND CENTRAL
MOUNTAINS...MOVE OUT QUICKLY MONDAY AFTERNOON...AS HIGH PRESSURE
BUILDS IN RAPIDLY FROM THE WEST AND ENDS THE COLD ADVECTION. WITH
NOT MUCH OF AN UPSLOPE EVENT AND MOISTURE RATHER SHALLOW...EXPECT
ONLY AN INCH OR TWO IN THE HIGHER ELEVATIONS BEFORE ENDING MONDAY
AFTERNOON. TEMPERATURES WILL BE BELOW NORMAL WITH MONDAY HIGHS
STRUGGLING TO REACH ABOVE FREEZING...EVEN WITH INCREASING SUNSHINE.
TUESDAY AND WEDNESDAY WILL SEE CLIPPER LIKE SYSTEMS TRACKING JUST TO
OUR NORTH...WITH THE MAIN EFFECT BEING SOME CLOUDS ACROSS THE NORTH
HALF OF THE AREA. PRECIP...HOWEVER...SHOULD ALSO STAY JUST NORTH
WHERE ALONG THE CLIPPER TRACK. TEMPERATURES WILL BE ON A SLOW RISE
TUESDAY AND WEDNESDAY WITH A WEAK SOUTHERLY FLOW...WITH HIGHS
REACHING TO NEAR NORMAL READINGS BY WEDNESDAY.
THE NEXT SIGNIFICANT LOW PRESSURE SYSTEM AND COLD FRONT FOR THURSDAY
WILL BE A REFLECTION OF THE DIGGING UPPER TROUGH. FORECAST
AMPLIFICATION OF THE UPPER TROUGH SUGGESTS THE TRACK OF THE SURFACE
LOW WILL BE CLOSE TO OUR AREA. THIS WILL PUT US ON THE EDGE OF
WINTRY VERSUS LIQUID PRECIP. FOR NOW...WILL KEEP A WINTRY MIX
THURSDAY AND THEN SNOW SHOWERS THURSDAY NIGHT BEHIND THE COLD FRONT.
BUT WOULD NOT BE SURPRISED TO SEE A NORTHWARD SHIFT OF THE SURFACE
LOW AND WARMER SCENARIO AHEAD OF THE COLD FRONT ON FUTURE MODEL
RUNS.
&&
.LONG TERM /THURSDAY THROUGH SATURDAY/...
LOW PRESSURE AND SNOW SHOWERS MOVE OUT FRIDAY. SNOW ACCUMULATIONS
ARE ANTICIPATED...ESPECIALLY OVER THE NORTHEAST MOUNTAINS BY EARLY
FRIDAY.
WPC CONTINUES HONORING THE ECMWF SOLUTION IN THE EXTENDED FORECAST.
BLENDED WPC AND GMOS FOR WINDS AND TEMPERATURES THROUGH THE PERIOD
DUE TO LOWER CONFIDENCE BEYOND DAY 4. TEMPERATURES WILL DEPEND ON
THE TRAJECTORIES OF THE AFOREMENTIONED SHORTWAVES AS THEY WILL
REINFORCE THE COLD AIR BEHIND ANY SFC REFLECTION...AND BRING PLENTY
OF CLOUDINESS.
&&
.AVIATION /13Z SUNDAY THROUGH THURSDAY/...
WITH SOLID RAIN COVERAGE ON RADAR...ONLY A MATTER OF TIME BEFORE
TERMINALS COME DOWN TO IFR CONDITIONS. AFTER 12Z...CEILINGS COULD
COME DOWN TO THE 0.3 TO 0.5KFT RANGE FOR 2 TO 4 HOURS. HAVE ADDED
TEMPO GROUPS TO THESE TERMINALS FOR IFR CEILINGS DURING THE
PREVAILING LIFR.
RAIN MOVES OUT AFTER 18Z TODAY AND THE WINDS WILL INCREASE. A COLD
FRONT APPROACHES AND WILL CROSS THE OHIO RIVER AFTER 03Z MONDAY.
SOME BRIEF SNOW ACCOMPANIES THE COLD FRONT CAUSING IFR
RESTRICTIONS THAT WILL BE FIT FOR TEMPO GROUPS IN FUTURE
ISSUANCES. LATE MONDAY NIGHT WILL SEE THE BEGINNING OF UPSLOPE
SNOW SHOWERS BEHIND THE FRONT...AFFECTING ALL TERMINALS EXCEPT PKB
AND HTS.
FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 12Z MONDAY...
FORECAST CONFIDENCE: MEDIUM.
ALTERNATE SCENARIOS: LIFR CONDITIONS MAY NOT MATERIALIZE.
OBSERVATIONS LIKELY TO BOUNCE IN THE RAIN BETWEEN LIFR AND MVFR.
AMENDMENTS LIKELY.
EXPERIMENTAL TABLE OF FLIGHT CATEGORY OBJECTIVELY SHOWS CONSISTENCY
OF WFO FORECAST TO AVAILABLE MODEL INFORMATION:
H = HIGH: TAF CONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL.
M = MEDIUM: TAF HAS VARYING LEVEL OF CONSISTENCY WITH MODELS.
L = LOW: TAF INCONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL.
UTC 1HRLY 11 12 13 14 15 16 17 18 19 20 21 22
EST 1HRLY 06 07 08 09 10 11 12 13 14 15 16 17
CRW CONSISTENCY M M M H H H H H H H H H
HTS CONSISTENCY H M M 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 M M M H M H H H M L L
PKB CONSISTENCY M L L H H H H H H H H H
CKB CONSISTENCY H H M M M H H H H H H H
AFTER 12Z MONDAY...
IFR POSSIBLE IN UPSLOPE SNOW SHOWERS AFTER 12Z MONDAY.
&&
.RLX WATCHES/WARNINGS/ADVISORIES...
WV...NONE.
OH...NONE.
KY...NONE.
VA...NONE.
&&
$$
SYNOPSIS...JMV/26
NEAR TERM...JSH/26
SHORT TERM...JMV
LONG TERM...ARJ
AVIATION...26
AREA FORECAST DISCUSSION
NWS CHARLESTON WV
543 AM EST SUN DEC 29 2013
.SYNOPSIS...
LOW PRESSURE MOVES UP THE EAST COAST TODAY. COLD FRONT LATE SUNDAY
NIGHT INTO MONDAY. HIGH PRESSURE TUESDAY. ANOTHER SYSTEM THURSDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
UPDATE...
NO CHANGES TO THE FORECAST THIS MORNING AS RAIN CONTINUES TO FALL
WITH A FEW BREAKS IN THE PRECIPITATION SHIELD HERE AND THERE.
PREVIOUS DISCUSSION...
EXTENSIVE SHIELD OF RAIN HAS NOW OVERSPREAD THE AREA...AND SHOULD
CONTINUE TO ENCOMPASS MOST COUNTIES THROUGH 12Z TODAY. SURFACE LOW
PRESSURE BRINGING THE MOISTURE INTO THE CWA WILL RACE UP THE EAST
COAST. WILL START LOSING THE DEPTH OF THIS MOISTURE AFTER 18Z
TODAY...AND WILL REDUCE THE POPS ACCORDINGLY AS THE UPPER AND MID
LEVELS ACQUIRE DRIER AIR. STILL EXPECTING TOTALS TO TOP OUT IN THE 1
TO 1.25 INCH RANGE...LIKELY OVER SOUTHWEST VIRGINIA AND THE SOUTHERN
MOUNTAINS.
TIMING IS STILL IN GOOD AGREEMENT AMONGST THE MODELS...BUT HAVE
FOCUSED ON THE HIGH RESOLUTION HRRR AND WRF MODELS FOR THE TIMING IN
TERMS OF DECREASING THE POPS THROUGH THE AFTERNOON AND EVENING.
MEANWHILE...A COLD FRONT CURRENTLY PLOWING THROUGH THE NORTHERN
PLAINS USHERING A BITTERLY COLD ARCTIC AIRMASS. THIS COLD FRONT WILL
RAPIDLY PUSH THROUGH THE SOUTHERN GREAT LAKES...AND WILL REACH OUR
SOUTHEAST OHIO COUNTIES AFTER 00Z MONDAY. IT WILL NOT BE BRINGING
QUITE THE SAME AIR CURRENTLY FILLING IN BEHIND THE FRONT IN
MINNESOTA AND THE DAKOTAS...BUT IT WILL BE A SIGNIFICANT AIRMASS
CHANGE FOR THE MIDDLE OHIO VALLEY. CAN EXPECT A FEW SNOW SHOWERS
WITH THE FRONT...AND THEN NORTHWESTERLY FLOW IN PLUNGING 850MB
TEMPERATURE AIR BRINGING UPSLOPING SNOW CONDITIONS THAT WILL EXTEND
INTO THE SHORT TERM FORECAST PERIOD.
NOT EXPECTING MUCH IN TERMS OF TEMPERATURE RECOVERY TODAY IN THE
RAIN...WITH UPPER 30S TO LOWER 40S EXPECTED. BEHIND THE COLD
FRONT...LOW 20S WILL FIND THEIR WAY INTO THE SOUTHEAST OHIO COUNTIES
BY 12Z MONDAY.
&&
.SHORT TERM /MONDAY THROUGH WEDNESDAY NIGHT/...
THIS PERIOD WILL BE CHARACTERIZED BY FAST WEST TO NORTHWEST FLOW
ALOFT...WITH A DIGGING NORTHERN STREAM UPPER TROUGH OVER THE
MISSISSIPPI AND OHIO VALLEYS BY THURSDAY. OPERATIONAL MODELS ARE
STRONGLY TRENDING TOWARD THIS SCENARIO. IN THIS FAST FLOW...POST
COLD FRONTAL SNOW SHOWERS...MAINLY IN THE NORTHERN AND CENTRAL
MOUNTAINS...MOVE OUT QUICKLY MONDAY AFTERNOON...AS HIGH PRESSURE
BUILDS IN RAPIDLY FROM THE WEST AND ENDS THE COLD ADVECTION. WITH
NOT MUCH OF AN UPSLOPE EVENT AND MOISTURE RATHER SHALLOW...EXPECT
ONLY AN INCH OR TWO IN THE HIGHER ELEVATIONS BEFORE ENDING MONDAY
AFTERNOON. TEMPERATURES WILL BE BELOW NORMAL WITH MONDAY HIGHS
STRUGGLING TO REACH ABOVE FREEZING...EVEN WITH INCREASING SUNSHINE.
TUESDAY AND WEDNESDAY WILL SEE CLIPPER LIKE SYSTEMS TRACKING JUST TO
OUR NORTH...WITH THE MAIN EFFECT BEING SOME CLOUDS ACROSS THE NORTH
HALF OF THE AREA. PRECIP...HOWEVER...SHOULD ALSO STAY JUST NORTH
WHERE ALONG THE CLIPPER TRACK. TEMPERATURES WILL BE ON A SLOW RISE
TUESDAY AND WEDNESDAY WITH A WEAK SOUTHERLY FLOW...WITH HIGHS
REACHING TO NEAR NORMAL READINGS BY WEDNESDAY.
THE NEXT SIGNIFICANT LOW PRESSURE SYSTEM AND COLD FRONT FOR THURSDAY
WILL BE A REFLECTION OF THE DIGGING UPPER TROUGH. FORECAST
AMPLIFICATION OF THE UPPER TROUGH SUGGESTS THE TRACK OF THE SURFACE
LOW WILL BE CLOSE TO OUR AREA. THIS WILL PUT US ON THE EDGE OF
WINTRY VERSUS LIQUID PRECIP. FOR NOW...WILL KEEP A WINTRY MIX
THURSDAY AND THEN SNOW SHOWERS THURSDAY NIGHT BEHIND THE COLD FRONT.
BUT WOULD NOT BE SURPRISED TO SEE A NORTHWARD SHIFT OF THE SURFACE
LOW AND WARMER SCENARIO AHEAD OF THE COLD FRONT ON FUTURE MODEL
RUNS.
&&
.LONG TERM /THURSDAY THROUGH SATURDAY/...
LOW PRESSURE AND SNOW SHOWERS MOVE OUT FRIDAY. SNOW ACCUMULATIONS
ARE ANTICIPATED...ESPECIALLY OVER THE NORTHEAST MOUNTAINS BY EARLY
FRIDAY.
WPC CONTINUES HONORING THE ECMWF SOLUTION IN THE EXTENDED FORECAST.
BLENDED WPC AND GMOS FOR WINDS AND TEMPERATURES THROUGH THE PERIOD
DUE TO LOWER CONFIDENCE BEYOND DAY 4. TEMPERATURES WILL DEPEND ON
THE TRAJECTORIES OF THE AFOREMENTIONED SHORTWAVES AS THEY WILL
REINFORCE THE COLD AIR BEHIND ANY SFC REFLECTION...AND BRING PLENTY
OF CLOUDINESS.
&&
.AVIATION /10Z SUNDAY THROUGH THURSDAY/...
WITH SOLID RAIN COVERAGE ON RADAR...ONLY A MATTER OF TIME BEFORE
TERMINALS COME DOWN TO IFR CONDITIONS. AFTER 12Z...CEILINGS COULD
COME DOWN TO THE 0.3 TO 0.5KFT RANGE FOR 2 TO 4 HOURS. HAVE ADDED
TEMPO GROUPS TO THESE TERMINALS FOR IFR CEILINGS DURING THE
PREVAILING LIFR.
RAIN MOVES OUT AFTER 18Z TODAY AND THE WINDS WILL INCREASE. A COLD
FRONT APPROACHES AND WILL CROSS THE OHIO RIVER AFTER 03Z MONDAY.
SOME BRIEF SNOW ACCOMPANIES THE COLD FRONT CAUSING IFR
RESTRICTIONS THAT WILL BE FIT FOR TEMPO GROUPS IN FUTURE
ISSUANCES. LATE MONDAY NIGHT WILL SEE THE BEGINNING OF UPSLOPE
SNOW SHOWERS BEHIND THE FRONT...AFFECTING ALL TERMINALS EXCEPT PKB
AND HTS.
FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 12Z MONDAY...
FORECAST CONFIDENCE: MEDIUM.
ALTERNATE SCENARIOS: LIFR CONDITIONS MAY NOT MATERIALIZE.
OBSERVATIONS LIKELY TO BOUNCE IN THE RAIN BETWEEN LIFR AND MVFR.
AMENDMENTS LIKELY.
EXPERIMENTAL TABLE OF FLIGHT CATEGORY OBJECTIVELY SHOWS CONSISTENCY
OF WFO FORECAST TO AVAILABLE MODEL INFORMATION:
H = HIGH: TAF CONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL.
M = MEDIUM: TAF HAS VARYING LEVEL OF CONSISTENCY WITH MODELS.
L = LOW: TAF INCONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL.
UTC 1HRLY 11 12 13 14 15 16 17 18 19 20 21 22
EST 1HRLY 06 07 08 09 10 11 12 13 14 15 16 17
CRW CONSISTENCY M M M H H H H H H H H H
HTS CONSISTENCY H M M 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 M M M H M H H H M L L
PKB CONSISTENCY M L L H H H H H H H H H
CKB CONSISTENCY H H M M M H H H H H H H
AFTER 12Z MONDAY...
IFR POSSIBLE IN UPSLOPE SNOW SHOWERS AFTER 12Z MONDAY.
&&
.RLX WATCHES/WARNINGS/ADVISORIES...
WV...NONE.
OH...NONE.
KY...NONE.
VA...NONE.
&&
$$
SYNOPSIS...JMV/26
NEAR TERM...26
SHORT TERM...JMV
LONG TERM...ARJ
AVIATION...26
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
1150 AM CST SUN DEC 29 2013
.DISCUSSION...
946 AM CST
GOING TO BE ONE OF THOSE DAYS...TIME FOR UPDATE #2 ALREADY.
REPORTS OF MULTIPLE ACCIDENTS WITH ICY ROADS IN SE WI AND NOW
COMING IN FROM LASALLE COUNTY...SO HAVE OPTED TO GO WITH AN
ADVISORY FOR FREEZING DRIZZLE. NOT EXPECTED TO BE A LONG DURATION
EVENT AND LIKELY MAINLY TRACE AMOUNTS...BUT GIVEN THE UPSTREAM
REPORTS AND POTENTIAL FOR SIMILAR CONDITIONS FARTHER EAST FELT THE
COURSE OF LEAST REGRET WAS TO QUICKLY GET OUT AN ADVISORY SINCE
THE FZDZ IS A LATE ADDITION TO THE FORECAST. OVER THE SE HALF OF
THE CWA WHERE TEMPERATURES GOT INTO THE 50S YESTERDAY THE PAVEMENT
TEMPERATURES ARE WARMER AND MAY TAKE LONGER FOR PROBLEMS TO
DEVELOP...BUT SINCE WE DONT HAVE ACCESS TO PAVEMENT TEMPS OR
EXPERIENCE FORECASTING THEM HAVE DECIDED TO INCLUDE THEM IN THE
ADVISORY TOO.
GRIDS ALREADY UPDATED...WSW IS OUT...AND ZFP/LFP ARE FORTHCOMING.
IZZI
//PREV DISCUSSION...
911 AM CST
HAVE MADE SOME ADJUSTMENTS TO PRECIP FORECAST FOR TODAY. UPSTREAM
OBS OVER SOUTHERN WISCONSIN INDICATE AT LEAST AREAS OF FREEZING
DRIZZLE HAVE BEEN OCCURRING. THE 12Z SOUNDINGS FROM GRB/DVN BOTH ARE
PRETTY CLASSIC FZDZ SOUNDINGS WITH FAIRLY DEEP SATURATED LOW LEVELS
WITH TOP OF THE SATURATED LAYER WARMER THAN -10C INDICATING A HIGH
PROBABILITY OF NO ICE NUCLEI IN THE CLOUDS...THUS MAKING SNOW
UNLIKELY. IR IMAGERY CONFIRMS THIS WITH CLOUD TOP TEMPS OF THE
STRATUS IN THE NEIGHBORHOOD OF -8 TO -11C ACROSS NORTHERN IL AND
SOUTHERN WISCONSIN. SHEAR WITHIN THE CLOUD LAYER APPEARS SUFFICIENT
TO SUPPORT COLLISION/COALESCENCE AND A DECENT SHOT OF FZDZ THREAT
CONTINUING INTO OUT CWA LATE THIS MORNING INTO THE EARLY AFTERNOON.
AS LOW LEVEL CONTINUE TO COOL THIS AFTERNOON IT APPEARS THAT TEMPS
WITHIN THE CLOUDS COULD COOL TO AROUND -12 TO -13C WHICH COULD BE
ENOUGH TO ALLOW FOR SOME ICE IN THE STRATUS AND AT LEAST THE
POTENTIAL FOR SOME LIGHT SNOW SHOWERS OR FLURRIES. GIVEN THE SHALLOW
DEPTH OF THE MOISTURE EXPECT TODAY`S PRECIP TO LARGELY BE A TRACE
EVENT...SO HAVE LOWERED THE CHANCE FOR MEASURABLE PRECIP INTO THE
LOW/MID CHANCE RANGE. IT IS WORTH NOTING...THAT IT REALLY ONLY TAKE
A TRACE OF FREEZING DRIZZLE TO CAUSE PROBLEMS AND WILL CONTINUE TO
CLOSELY MONITOR CONDITIONS FOR ANY POSSIBLE SHORT DURATION HEADLINE
OR TO HIT THE FZDZ POTENTIAL HARDER IN THE FORECAST.
SIGNIFICANT DRY AIR ADVECTION LATER THIS AFTERNOON SHOULD PUT AN END
TO THE LIGHT PRECIP THREAT BY MID TO LATE AFTERNOON WITH SKIES
EXPECTED TO CLEAR TONIGHT.
IZZI
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 18Z...
* FREEZING DRIZZLE THROUGH EARLY AFTERNOON.
* FLURRIES/VERY LIGHT SNOW MID/LATE AFTERNOON.
* MVFR CIGS THROUGH EARLY MONDAY MORNING.
* POSSIBLE IFR CIGS EARLY THIS AFTERNOON.
* GUSTY NORTHERLY WINDS TURNING NORTHWEST THIS AFTERNOON...THEN
DIMINISHING THIS EVENING. CMS
//DISCUSSION...UPDATED 18Z...
COLD FRONT IS NOW SOUTH OF THE TERMINALS WITH NORTHERLY WINDS
GUSTING INTO THE MID 20 KT RANGE. WIND DIRECTIONS WILL SLOWLY TURN
MORE NORTHWESTERLY THROUGH THE AFTERNOON AND THEN REMAIN NORTHWEST
INTO THIS EVENING. WIND SPEEDS/GUSTS WILL ALSO SLOWLY DECREASE
THROUGH THE MID/LATE AFTERNOON WITH GUSTS COMPLETELY ENDING BY MID
EVENING.
THE SATURATED LOW LEVELS REMAINED TOO WARM FOR SNOW/ICE CRYSTAL
FORMATION THIS MORNING AND THUS AS THE COLDER AIR SPREAD INTO THE
AREA...FREEZING DRIZZLE DEVELOPED. THIS WILL END OVER THE NEXT FEW
HOURS...FROM NORTH TO SOUTH. STILL THE POTENTIAL FOR SOME FLURRIES
OR VERY LIGHT SNOW...BUT NOT EXPECTING ANYTHING SIGNIFICANT OR ANY
ACCUMULATION.
AS DRIER AIR ADVECTS INTO THE AREA THIS AFTERNOON...CIGS SHOULD
CONTINUE TO LIFT INTO AND REMAIN MVFR INTO THIS EVENING AND
CURRENT CIG TRENDS MAY BE A BIT TOO PESSIMISTIC IN THE SHORT TERM.
BACK EDGE OF CLOUD COVER EXTENDS FROM CENTRAL WI BACK INTO EASTERN
IA AND WILL SLOWLY MOVE SOUTHEAST ACROSS THE TERMINALS LATE THIS
EVENING INTO EARLY MONDAY MORNING. CMS
//ORD AND MDW CONFIDENCE...UPDATED 18Z...
* HIGH FOR FREEZING DRIZZLE EARLY THIS AFTERNOON.
* LOW FOR FLURRIES/VERY LIGHT SNOW MID/LATE THIS AFTERNOON.
* HIGH FOR MVFR CIGS THROUGH LATE TONIGHT.
* LOW FOR IFR CIGS EARLY THIS AFTERNOON.
* HIGH FOR WIND SPEEDS/GUSTS/DIRECTIONS THIS AFTERNOON...MEDIUM
FOR THE REST OF THE PERIOD. CMS
//OUTLOOK FOR ORD/MDW FOR 00Z TUESDAY-12Z SUNDAY...UPDATED 12Z...
MONDAY NIGHT...LIGHT SNOW LIKELY IN THE EVENING WITH A PERIOD OF
MVFR AND IFR CONDITIONS.
TUESDAY...CHANCE OF LIGHT SNOW LATE AFTERNOON...SNOW LIKELY TUE
NIGHT. MVFR BECOMING IFR
WEDNESDAY...CHANCE OF SNOW. MVFR.
THURSDAY...CHANCE OF SNOW. MVFR.
FRIDAY...VFR.
SATURDAY...VFR.
TRS
&&
.MARINE...
433 AM CST
A LOW OVER NORTHERN LOWER MI WILL CONTINUE EASTWARD...DRAGGING A
STRONG COLD FRONT DOWN PAST THE SOUTH TIP OF THE LAKE EARLY TO
MID MORNING...WHILE A STRONG HIGH OVER THE NORTHERN AND CENTRAL
PLAINS SPREADS S AND E...AND ACROSS THE MID MS VALLEY ON MON.
FOLLOWING THE PASSAGE OF THE COLD FRONT IS VERY COLD AIR
SPREADING ACROSS THE UPPER MIDWEST...THE WESTERN GREAT LAKES AND
THE MID MS VALLEY. THE COMBINATION OF THE VERY STRONG COLD AIR
ADVECTION AND A STRONG PRESSURE GRADIENT WILL LEAD TO NW TO N
GALES DEVELOPING ACROSS THE N PORTION OF THE LAKE BY
DAWN...SPREADING DOWN TO THE FAR S PORTION BY LATE MORNING.
THE VERY COLD AIR...STRONG WINDS AND HIGH WAVES WILL LEAD TO THE
POTENTIAL FOR MODERATE TO HEAVY FREEZING SPRAY...WITH THE
GREATEST CHANCE FOR HEAVY FREEZING SPRAY TO OCCUR DURING THIS
AFTERNOON AND THIS EVENING AS TEMPERATURES DROP INTO THE TEENS
AND LOWER 20S. THERE IS THE POTENTIAL FOR SOME HEAVY SPRAY TO
LINGER AS WINDS DROP BELOW GALE FORCE DUE TO THE SLOWER DECREASE
IN WAVE HEIGHTS AND THE ADVECTION OF EVEN COLDER AIR WELL BEHIND
THE FRONT.
ANOTHER ARCTIC HIGH BUILDING INTO THE NORTHERN PLAINS TUE WILL
RESULT IN STRONG NW WINDS ON LAKE MI TUE AND TUE NIGHT ALTHOUGH
THIS SYSTEM SHOULD BE ACCOMPANIED BY A LESSER PRESSURE GRADIENT
AND THE AIR MASS WILL NOT BE QUITE AS COLD...SO ANOTHER ROUND
GALES AND FREEZING SPRAY IS NOT ANTICIPATED AT THIS TIME.
FOR THE NEARSHORE WATERS...THE BETTER CHANGE FOR GALES TODAY
WILL BE OVER THE IN WATERS DUE TO THE DIRECT N TO NW FETCH
PREDOMINANTLY OVER ALL WATER...WHILE THE IL NEARSHORE WATERS
SHOULD REMAIN BELOW GALE FORCE DUE TO SLIGHTLY WEAKER FLOW OFF
LAND. THE GREATEST RISK OF HEAVY FREEZING SPRAY WILL BE ON THE IN
NEARSHORE WATERS...THOUGH ON THE IL NEARSHORE WATERS THERE WILL
LIKELY HEAVY FREEZING SPRAY AS ONE NEARS THE 5 NM FROM SHORE
BOUNDARY AS THE LARGEST WAVES ON THE IL WATERS WILL BE FOUND OUT
NEAR THE OPEN WATERS.
WINDS AND WAVES WILL DIMINISH AS THE HIGH SPREADS E MON NIGHT AND
TUE...BUT ANOTHER LOW IS EXPECTED TO DEVELOP OVER THE NORTHERN
PLAINS MON MORNING AND TRACK E ACROSS NORTHERN IL MON
NIGHT...CONTINUING TO THE EASTERN GREAT LAKES TUE MORNING.
TRS
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...FREEZING RAIN ADVISORY...ILZ004-ILZ005-ILZ006-ILZ011-ILZ012-
ILZ013-ILZ014-ILZ019-ILZ020-ILZ021-ILZ022-ILZ023-ILZ032-
ILZ033-ILZ039 UNTIL 2 PM SUNDAY.
WIND CHILL ADVISORY...ILZ003-ILZ004-ILZ005-ILZ006-ILZ008-ILZ010-
ILZ011-ILZ012-ILZ019-ILZ020-ILZ021-ILZ032...9 PM SUNDAY TO
NOON MONDAY.
IN...FREEZING RAIN ADVISORY...INZ001-INZ002-INZ010-INZ011-INZ019
UNTIL 2 PM SUNDAY.
LM...GALE WARNING...LMZ080-LMZ567-LMZ669-LMZ671-LMZ673-LMZ675-LMZ740-
LMZ741-LMZ742-LMZ743-LMZ744-LMZ745-LMZ777-LMZ779-LMZ868-
LMZ870-LMZ872-LMZ874-LMZ876-LMZ878 UNTIL 9 PM SUNDAY.
HEAVY FREEZING SPRAY WARNING...LMZ080-LMZ261-LMZ362-LMZ364-
LMZ366-LMZ563-LMZ565-LMZ567-LMZ669-LMZ671-LMZ673-LMZ675-
LMZ740-LMZ741-LMZ742-LMZ743-LMZ744-LMZ745-LMZ777-LMZ779-
LMZ868-LMZ870-LMZ872-LMZ874-LMZ876-LMZ878 UNTIL MIDNIGHT
MONDAY.
GALE WARNING...LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-LMZ565 UNTIL 6
PM SUNDAY.
SMALL CRAFT ADVISORY...LMZ740-LMZ741-LMZ742-LMZ743...9 PM SUNDAY
TO 4 AM MONDAY.
&&
$$
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Area Forecast Discussion
National Weather Service Lincoln IL
1123 AM CST Sun Dec 29 2013
.DISCUSSION...
ISSUED 1018 AM CST Sun Dec 29 2013
Cold front has crossed I-70 and should be through the far
southeast CWA in the next hour. Have been having some freezing
drizzle/mist on the backside of the front, especially along and
north of I-74, although some reports have come in from as far
south as I-72. Upstream morning sounding from Davenport IA and
forecast soundings from the RAP model support this with little ice
crystals aloft to suggest snow. Forecast was updated around 8 am
to add the freezing drizzle, and new update sent scaled back the
snow potential and PoP`s, especially for this afternoon. Have
updated the hourly temperature trends, and should see the far
northwest CWA down into the 10-15 range by sunset.
Geelhart
&&
.AVIATION...
ISSUED 1123 AM CST Sun Dec 29 2013
IFR/LIFR conditions continuing from KPIA-KCMI late this morning,
although worst of the conditions now from KBMI southeast. Will
continue to see some patchy freezing drizzle for a couple hours.
This is a very fine drizzle/mist, and is most easily tracked with
surface visibilities below 3SM. Visibility at KPIA has come up to
5SM recently and ceilings should come up above 1000 feet shortly.
Further south, the IFR ceilings will be improving over the next
couple hours, but again will still be just above 1000 feet. RAP
model shows ceilings scattering out generally between 00-03Z
although taking a bit longer at KCMI. Northwest winds expected to
continue gusting to 20-25 knots into early evening until skies
clear.
Geelhart
&&
.PREV DISCUSSION...
ISSUED 330 AM CST Sun Dec 29 2013
Will issue a wind chill advisory for northern 10 counties from 9
pm this evening until 9 am Monday morning for wind chills of 15 to
20 below zero. The wind chill advisory is roughly along and north
of a Rushville to Bloomington line.
SHORT TERM...Today through Tuesday night
Arctic cold front extends from 1005 mb low pressure over northern
lower MI through southeast WI into NW IL (recently passing SE of
Galesburg) and into central MO. Relatively mild temps in the mid
to upper 30s over central and southeast IL with 41F at Robinson.
Area of light rain over far southeast IL (along and southeast of a
Robinson to Flora line) and into KY/TN and southern IN and
associated with isentropic lift ahead of weakening 558 dm 500 mb
low over the red river valley along the OK/Texas border. This
upper level low to continue to weaken/open up as it ejects into
the TN valley today taking its light rain out of IL early this
morning. Main weather story today will be strong arctic cold front
that quickly sweeps SE through central IL through mid morning and
passes SE of the Wabash river late this morning. Expect temps to
drop behind the cold front with brisk/gusty NW winds behind front
as temps fall to 10F at Galesburg by sunset and near 30F by
Lawrenceville in far southeast IL. NAM models remains dry today
but some other high res models like RAP, HRRR and SREF show
patches of light QPF over mainly northern counties from 15Z-22Z
today. Mainly think scattered flurries with a few light snow
showers possible over mainly northern counties today and not
expecting any accumulations.
Clouds decrease tonight and very cold lows in the single digits
below zero over IL river valley where wind chills reach 15 to 20
below zero by late evening until around 9 am Monday morning. Will
issue a wind chill advisory as stated earlier. Clouds to increase
from NW during Monday and quite cold with highs in the teens over
central IL and lower 20s in southeast IL. A northern stream short
wave to bring chance of light snow to northern areas Monday night.
With another one bringing chances of light snow to northern areas
Tue afternoon and over much of area Tue night with some light snow
accumulations possible mainly north of I-74. Temps to stay well
below normal into the middle of the week.
LONG TERM...Wednesday through Sunday
Medium to long range forecast models and ensembles continue to
show a strong upper level trof digging back into the MS river
valley Wednesday night and Thursday...and models trending with a
deepening surface low pressure ejecting from the central plains
into the Ohio river valley by Thursday morning. Accumulating snows
appear more likely now to fall north of this low pressure track
over central IL and increased pops north Wednesday and across area
Wed night, and best chances of snow shifting east of IL during
Thursday. Trended temperatures colder behind this storm system Thu
night and Friday as below normal temps continue. Large upper level
trof shifts east of IL Fri/Sat with temps moderating closer to
normal next weekend.
07
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
WIND CHILL ADVISORY from 9 PM this evening to 9 AM CST Monday
FOR ILZ027>031-036>038-040-041.
&&
$$
AREA FORECAST DISCUSSION
NWS QUAD CITIES IA IL
1123 AM CST SUN DEC 29 2013
.UPDATE...
ISSUED AT 840 AM CST SUN DEC 29 2013
A QUICK UPDATE SENT TO SLIGHTLY CHANGE THE OUTLINE OF WIND CHILL
ADVISORY COUNTIES IN WEST CENTRAL ILLINOIS. WE HAVE ADDED THE
COUNTIES OF DES MOINES...HENDERSON...WARREN...AND MCDONOUGH. WHILE
CRITERIA IS MARGINAL FOR WIND CHILLS...THE COLLABORATION WITH
SURROUNDING OFFICES WILL CONVEY A MUCH MORE CONSISTENT MESSAGE
WITH THE INCLUSION OF THESE COUNTIES.
ERVIN
UPDATE ISSUED AT 726 AM CST SUN DEC 29 2013
BASED ON RADAR DUAL POL DATA IN CONCERT WITH WEAK VISIBILITY
RESTRICTIONS FROM THE LIGHT PRECIPITATION...HAVE ADDED PATCHY
FREEZING DRIZZLE THROUGH MID MORNING TO THE FORECAST.
IF THE TRENDS IN THE RAP ARE CORRECT...THE CURRENT FORCING MOVING
THROUGH THE AREA WITH DRIER AIR ALOFT IS PRODUCING SOME LIGHT SNOW
MIXED WITH VERY LIGHT FREEZING DRIZZLE. THIS SHALLOW MOISTURE
SHOULD EXIT THE AREA SHORTLY AFTER MID MORNING.
ACROSS CENTRAL IOWA...THERE IS ANOTHER AREA OF FORCING BUT THE
MOISTURE IS A BIT DEEPER BASED ON CONDENSATION PRESSURE DEFICITS.
HERE PRECIPITATION IS STILL LIGHT BUT OBSERVATIONS AND RADAR DATA
SUGGEST MORE FLURRIES OR VERY LIGHT SNOW INSTEAD OF FREEZING DRIZZLE.
REGARDING THE CURRENT HEADLINES...THE COLDER AIR IS NOT MOVING IN
AS FAST AS THE SHORT RANGE MODEL TRENDS HAVE BEEN SUGGESTING. THIS
OBSERVATIONAL TREND BRINGS QUESTIONS AS TO WHETHER OR NOT 15 BELOW
ZERO IS ACHIEVABLE TONIGHT IN AREAS WEST OF A DUBUQUE TO IOWA CITY
LINE. IF THIS IS THE CASE...THEN WIND CHILLS WOULD NOT PROBABLY
NOT EXCEED 30 BELOW ZERO EITHER. THIS AREA IS RIGHT ON THE CUSP
BETWEEN AN ADVISORY AND A WARNING FOR WIND CHILL. TRENDS THROUGH
THE DAY WILL BE CRITICAL IN DETERMINING WHICH WAY THE HEADLINE
WILL EVENTUALLY GO FOR TONIGHT.
UPDATE ISSUED AT 532 AM CST SUN DEC 29 2013
TEMPERATURES ARE FALLING BUT NOT NEARLY AS FAST AS PREVIOUSLY
THOUGHT. OVERNIGHT LOWS ARE STILL EXPECTED 7-9 AM WITH HIGHS 8-10
AM THAT ARE ONLY 1-2 DEGREES ABOVE THE OVERNIGHT LOWS.
TEMPERATURES ARE THEN EXPECTED TO SLOWLY FALL THROUGH THE DAY.
RADAR AND VISIBILITY TRENDS ARE SUGGESTING THE CURRENT VERY LIGHT
PRECIPITATION WILL BE MOVING EAST OF THE MISSISSIPPI THIS MORNING
WITH POSSIBLY SOME FLURRIES. BASED ON DATA FROM THE 12Z
SOUNDING...VERY LIGHT FREEZING DRIZZLE CANNOT BE RULED OUT EITHER.
ALTHOUGH PAVEMENT TEMPERATURES ARE GENERALLY AT OR BELOW
FREEZING...THE STRONG WIND IS PROMOTING EVAPORATION WHICH MAY
LIMIT OR REDUCE ANY FREEZING DRIZZLE ACCUMULATION ON ROADS.
&&
.SYNOPSIS...
ISSUED AT 317 AM CST SUN DEC 29 2013
06Z SFC ANALYSIS HAD A LOW IN CENTRAL WISCONSIN WITH A WEAK TROF
RUNNING FROM THE LOW INTO NORTHEAST MISSOURI. THE ARCTIC FRONT RAN
FROM WESTERN UPPER MICHIGAN...TO KANSAS CITY... AND THEN TO AROUND
KAMA. DEW POINTS ALONG AND AHEAD OF THE ARCTIC FRONT WERE IN THE
20S AND 30S WITH TEENS AND COLDER BEHIND THE FRONT INTO THE PLAINS.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 317 AM CST SUN DEC 29 2013
THE ARCTIC FRONT IS GENERALLY ALONG THE MISSISSIPPI AT 09Z AND
SHOULD BE OVER THE FAR EASTERN AREAS BY SUNRISE. WINDS JUMP
QUICKLY BEHIND THE FRONT WITH SUSTAINED WINDS OF 15 TO 25 MPH WITH
GUSTS OVER 30 MPH. LOW TEMPERATURES THIS MORNING WILL OCCUR 7-9 AM
WITH MAX TEMPERATURES IN THE 8-10 AM TIME FRAME. AT BEST MOST OF
THE AREA WILL ONLY SEEN A 1-2 DEGREE RISE BEFORE TEMPERATURES
START FALLING THROUGH THE DAY.
MOISTURE IN THE LOWER ATMOSPHERE IS NOT AS GREAT AS ORIGINALLY
SUGGESTED. THUS MAINLY FLURRIES WILL BE SEEN DURING THE DAY WITH
SOME AREAS OF LIGHT SNOW. AT BEST ANY ACCUMULATION WOULD BE A DUSTING.
THE CURRENT WIND CHILL ADVISORY HAS BEEN DELAYED UNTIL LATE
MORNING BASED ON EXPECTED TEMPERATURES AND WINDS.
TONIGHT...DRY CONDITIONS ARE EXPECTED AS THE NEXT ARCTIC HIGH
BUILDS INTO THE MIDWEST. BASED ON PROJECTED LOWS AND WIND...AREAS
GENERALLY EAST OF THE CURRENT WIND CHILL ADVISORY WILL MET WIND
CHILL CRITERIA TONIGHT INTO MONDAY MORNING.
AREAS WEST OF A DUBUQUE TO IOWA CITY LINE MAY SEE WIND CHILLS
EXCEED 30 BELOW TONIGHT BEFORE THE ARRIVAL OF THE ARCTIC HIGH. IF
THIS OCCURS...THEN A WIND CHILL WARNING WOULD BE NEEDED FOR THAT
AREA. HOWEVER...TEMPERATURES MAY NOT DROP OFF AS QUICKLY AS
FORECAST AND WINDS MAY NOT BE AS STRONG WHICH WOULD RESULT IN WIND
CHILLS OF ONLY 30 BELOW ZERO. THIS SITUATION WILL HAVE TO BE MONITORED
CAREFULLY DURING THE DAY IN CASE THE ADVISORY WOULD NEED TO BE UPGRADED.
.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 317 AM CST SUN DEC 29 2013
SNOWIER PATTERN APPEARS IN STORE FOR THE AREA THROUGHOUT THE
EXTENDED AS SEVERAL CLIPPER SYSTEMS ARE SHUTTLED DOWN
OVER THE REGION IN ACTIVE NORTHWEST FLOW.
TEMPS THROUGHOUT THE PERIOD TO REMAIN WELL BELOW NORMAL IN
THE NORTHWEST FLOW. CHALLENGE IN TIME WILL BE IMPACT
OF NEGATIVE FEEDBACK FROM FRESH NEW SNOW COVER ON TEMPS.
IF SOME AREAS SEE 2-5+ INCHES OF NEW SNOW AS IS LOOKING
QUITE REASONABLE AT THIS TIME THEN GOING TEMPS ESPECIALLY
OVER THE LATTER HALF OF THE PERIOD WILL LIKELY NEED TO BE
LOWERED.
FIRST ROUND OF ACCUMULATING SNOW ANTICIPATED MON AFTN/EVE
ESPECIALLY ACROSS THE NORTH 1/2 TO POSSIBLY 2/3RDS OF CWA WITH
CLIPPER SYSTEM AND ATTENDANT WARM ADVECTION. LIQUID PCPN
AMOUNTS LOOK TO BE LIGHT AND LESS THAN 0.1 INCH BUT HIGH SNOW
TO LIQUID RATIOS OF 15-20+:1 SUPPORTIVE OF AN INCH OR TWO
OF ACCUMULATION WITH THE HIGHER AMOUNTS FAVORING AREAS NORTH
OF I-80.
ANOTHER CLIPPER SYSTEM THEN FOLLOWS ABOUT 24+ HRS LATER OR LATE
TUE AFTN/NGT WITH SIMILAR LIGHT QPF AND HIGH RATIO EVENT
FOR ANOTHER INCH OR POSSIBLY TWO OF SNOW ESPECIALLY NEAR TO
NORTH OF I-80.
MODELS ARE THEN COMING INTO BETTER AGREEMENT ON A MUCH STRONGER
SYSTEM FOR WED/WED NGT. BETTER MOISTURE AND GOOD DYNAMICS IN
TERMS OF DIGGING SHORTWAVE AND COUPLED UPPER JET STRUCTURE
SUGGESTIVE OF MODERATE QPF EVENT OF 0.25-0.4 INCH POSSIBLE WHICH
WITH SNOW TO LIQUID RATIOS OF 13-17:1 WOULD RESULT IN 3-6 INCH
POTENTIAL SNOW ACCUMS. STILL WAY EARLY IN THE GAME AND OF COURSE
A LOT OF UNCERTAINTY WITH TRACK... BUT THE MAGNITUDE OF FORCING
AND MOISTURE WILL MAKE THIS ONE TO WATCH IN THE COMING DAYS.
MODELS THEN SUGGEST POTENTIAL OF A QUITE PERIOD LATE WEEK AND
INTO NEXT WEEKEND AS THE FLOW PATTERN APPEARS SET TO UNDERGO
TRANSITION TO SOUTHWESTERLY FLOW BY EARLY NEXT WEEK. LATEST RUNS
OF GFS AND ECMWF THEN SHOW AN EVEN STRONGER SYSTEM EJECTING FROM
THE SOUTHWEST AND THROUGH THE CENTRAL CONUS EARLY NEXT WEEK WHICH
COULD BRING MORE SNOW OR A WINTRY MIX TO THE REGION.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY AFTERNOON)
ISSUED AT 1112 AM CST SUN DEC 29 2013
BITTERLY COLD NORTHWEST WINDS OF 15 TO 28KTS WILL CONTINUE TO BLOW
THROUGH EARLY EVENING TODAY...ALONG WITH PASSING FLURRIES AND MVFR
CIGS BETWEEN 1500 AND 2500 FT. TOWARDS LATE AFTERNOON...CIGS
SHOULD SCATTER OUT TO A CLEAR SKY LASTING THROUGH THE NIGHT. WINDS
WILL BECOME LIGHT BY LATE EVENING...AND WILL REMAIN LIGHT
NORTHWEST UNTIL MID MORNING MONDAY...WHEN A SHIFT TO LIGHT
SOUTHEAST WINDS ARE EXPECTED AT ALL SITES. THIS WILL ALSO SEE THE
ONSET OF MORE MID CLOUDS...RUNNING AHEAD OF A FAST MOVING STORM
SYSTEM WHICH MAY BRING SNOW TO IOWA AND NORTHERN ILLINOIS MONDAY
AFTERNOON AND NIGHT.
ERVIN
&&
.DVN WATCHES/WARNINGS/ADVISORIES...
IA...WIND CHILL ADVISORY FROM 5 PM THIS AFTERNOON TO NOON CST MONDAY
FOR CLINTON-DES MOINES-HENRY IA-JACKSON-LOUISA-MUSCATINE-
SCOTT.
WIND CHILL ADVISORY UNTIL NOON CST MONDAY FOR BENTON-BUCHANAN-
CEDAR-DELAWARE-DUBUQUE-IOWA-JEFFERSON-JOHNSON-JONES-KEOKUK-
LINN-WASHINGTON.
IL...WIND CHILL ADVISORY FROM 5 PM THIS AFTERNOON TO NOON CST MONDAY
FOR BUREAU-CARROLL-HENDERSON-HENRY IL-JO DAVIESS-MCDONOUGH-
MERCER-PUTNAM-ROCK ISLAND-STEPHENSON-WARREN-WHITESIDE.
MO...NONE.
&&
$$
UPDATE...ERVIN
SYNOPSIS...08
SHORT TERM...08
LONG TERM...05
AVIATION...ERVIN
AREA FORECAST DISCUSSION
NWS GRAY ME
333 PM EST SUN DEC 29 2013
.SYNOPSIS...
LOW PRESSURE WILL MOVE RAPIDLY THROUGH THE GULF OF MAINE TONIGHT
AND WILL BE LOCATED NEAR HALIFAX NOVA SCOTIA BY MONDAY MORNING.
HIGH PRESSURE WILL BUILD OVER THE REGION MONDAY. WEAK LOW PRESSURE
WILL MOVE THROUGH CENTRAL NEW ENGLAND TUESDAY AFTERNOON. HIGH
PRESSURE WILL BUILD OVER THE REGION WEDNESDAY. LOW PRESSURE WILL
GATHER STRENGTH OVER THE MID ATLANTIC STATES THURSDAY AND MOVE
NORTHEAST SOUTH OF CAPE COD FRIDAY. HIGH PRESSURE WILL BUILD OVER
THE NORTHEAST SATURDAY AND MOVE SOUTHEAST OF THE REGION SUNDAY.
&&
.NEAR TERM /TONIGHT/...
COLD FRONT HAS PUSHED SOUTH THROUGH THE MIDCOAST AND IS NOW
LOCATED FROM WISCASSET TO LEWISTON BEFORE GETTING HUNG UP IN THE
HILL COUNTRY NEAR RUMFORD. TEMPERATURES BEHIND THE FRONT HAVE BEEN
FALLING INTO THE MID 20S AS NOTED OVER THE PAST FEW HOURS AT
BANGOR AND WATERVILLE. THIS FRONT MAY PLAY A KEY ROLE IN
DETERMINING PRECIPITATION TYPE ACROSS THE MIDCOAST REGION TONIGHT.
LOW PRESSURE CURRENTLY JUST SOUTHEAST OF PHILADELPHIA WILL TRACK
QUICKLY NORTHEAST ACROSS CAPE COD AND TO NOVA SCOTIA TONIGHT.
LARGE AREA OF PRECIPITATION HAS SPREAD NORTHWARD AHEAD OF THIS
LOW... NOW SPREADING ACROSS ALL OF SOUTHERN NEW ENGLAND AND
PUSHING INTO SOUTHERN NEW HAMPSHIRE. THIS PRECIPITATION WILL
CONTINUE TO SPREAD NORTHEAST ACROSS NEW HAMPSHIRE AND MAINE
OVERNIGHT... BRINGING A QUICK... BUT HEAVY... ROUND OF
PRECIPITATION BEFORE EXITING JUST AFTER MIDNIGHT.
PRECIPITATION TYPE CONTINUES TO BE A COMPLEX PICTURE WITH THIS
STORM... AS TEMPERATURES THROUGH THE LOWEST FEW THOUSAND FEET WILL
BE NEAR FREEZING ACROSS MUCH OF SOUTHERN NEW HAMPSHIRE AND COASTAL
MAINE. NAM AND HRRR MODELS CONTINUE TO SHOW A COLDER SOLUTION...
WITH TEMPERATURES AT OR JUST BELOW FREEZING AS PRECIPITATION FALLS
THIS EVENING. IT IS EXPECTED THAT AS PRECIPITATION BEGINS TO
INTENSIFY... TEMPERATURES WITHIN THE ATMOSPHERIC PROFILE WILL COOL
AND ALLOW A HEAVY WET SNOW TO FALL. LOTS OF MOISTURE AND GOOD
DYNAMICS WITH THIS SYSTEM WILL ALLOW INTENSE PRECIPITATION
RATES... WITH TOTAL QPF TONIGHT RANGING FROM 0.75 TO 1.00 INCH.
SNOW RATIOS WILL BE NEAR 10 TO 1 DUE TO THE LARGE ISOTHERMAL LAYER
IN THE LOW LEVELS ESPECIALLY OVER SOUTHERN AND CENTRAL NEW
HAMPSHIRE EXTENDING TO THE MAINE COAST. NORTH OF THE PREVIOUSLY
MENTIONED COLD FRONT... TEMPERATURES WILL BE A BIT COLDER...
LEADING TO MORE CERTAINTY THAT PRECIPITATION WILL FALL IN THE FORM
OF SNOW AND ALLOW SNOW RATIOS TO BE A BIT HIGHER... POSSIBLY 13 TO
1.
THERE IS A GOOD AMOUNT OF CONFIDENCE THAT A BAND OF 6 TO 10 INCHES
OF SNOW WILL FALL... THOUGH THE TRANSITION TO RAIN NEAR THE COAST
IS STILL THE BIGGEST QUESTION MARK. IT IS POSSIBLE THAT THE
IMMEDIATE COASTLINE MAY SEE ONLY AN INCH OR TWO OF SNOW WHILE
AREAS JUST INLAND COULD SEE 6 TO 10. WITH THE COLDER FORECAST...
THE WINTER STORM WARNINGS HAVE BEEN EXTENDED TO THE COAST FROM
PORTLAND EASTWARD. THIS AREA WAS ALSO HIT HARD BY THE ICE STORM
LAST WEEKEND AND THE TREES ARE LIKELY STILL SUPPORTING A LOAD OF
ICE FROM THIS. WITH THE ADDITIONAL STICKY... WET SNOW EXPECTED...
THIS COULD CAUSE ADDITIONAL POWER OUTAGES EVEN IF THE 6 INCH
WARNING CRITERIA IS NOT MET.
SNOWFALL RATES WILL LIKELY BE QUITE INTENSE THIS EVENING... WITH 1
TO 2 INCHES PER HOUR COMMON AND RATES UP TO 3 INCHES PER HOUR
POSSIBLE. THIS WILL MAKE IT MORE DIFFICULT FOR ROAD CREWS TO KEEP
UP WITH SNOW REMOVAL DURING THE HEAVIEST PERIOD OF SNOW... CAUSING
EVEN GREATER IMPACTS ON TRAVEL. ALL THESE FACTORS WERE CONSIDERED
IN THE PLACING OF WINTER STORM WARNINGS AND WINTER WEATHER ADVISORIES.
FURTHER TO THE NORTH... THERE WILL LIKELY BE A SHARP CUT OFF IN
SNOWFALL AMOUNTS INLAND OF THE HEAVIEST BAND. LOCATIONS NEAR THE
CANADIAN BORDER MAY NOT SEE MUCH SNOW AT ALL... AND NORTHERN COOS
COUNTY HAS BEEN DROPPED FROM THE ADVISORY AS FORECAST SNOWFALL
AMOUNTS IN THIS REGION ARE ONLY 1 TO 2 INCHES. THE NORTHERN ZONES
IN WESTERN MAINE WERE LEFT IN AS THE SOUTHERN PORTION OF THESE
ZONES STILL HAS A THREAT FOR HIGHER TOTALS.
&&
.SHORT TERM /MONDAY AND MONDAY NIGHT/...
AS LOW PRESSURE MOVES EAST... A COLD FRONT WILL PUSH SOUTHEAST
ACROSS NEW ENGLAND ON MONDAY. A VERY COLD AIR MASS HAS BEEN
LURKING BEHIND THIS FRONT... AND THIS WILL BE FELT IN FULL FORCE
BY MONDAY AFTERNOON. TEMPERATURES WILL LIKELY BE FALLING THROUGH
THE DAY AS COLD ADVECTION TAKES OVER. WINDS COULD GUST TO 25 MPH
AS COLD ADVECTION ALLOWS GOOD MIXING TO TAKE PLACE.
TEMPERATURES FALL TO NEAR OR BELOW ZERO ACROSS THE ENTIRE FORECAST
AREA MONDAY NIGHT. READINGS AS COLD AS 20 BELOW ARE POSSIBLE TO
THE NORTH OF THE MOUNTAINS WHERE COLD AIR WILL BE EVEN MORE
INTENSE. WIND CHILL ADVISORIES OR WARNINGS MAY BE NEEDED AS WIND
CHILLS COULD REACH 30 BELOW.
&&
.LONG TERM /TUESDAY THROUGH SUNDAY/...
MODELS IN AGREEMENT THROUGH THE PERIOD FOR A COLD WEEK. A WEAK SHORT
WAVE WILL MOVE THROUGH NEW HAMPSHIRE AND MAINE TUESDAY AFTERNOON
WITH ASSOCIATED SNOW SHOWERS AND USHER IN EVEN COLDER AIR. WIND
CHILL ADVISORIES MAY BE NEEDED TUESDAY NIGHT AND WEDNESDAY. HIGH
PRESSURE CRESTS OVERHEAD WEDNESDAY. LATE IN THE DAY CLOUDS STREAM
EAST. LIGHT SNOW DEVELOPS THURSDAY AS LOW PRESSURE DEVELOPS SOUTH
OF LONG ISLAND NEW YORK. GFS AND ECMWF SIMILAR IN THE TRACK AND
LINGER SNOW INTO FRIDAY. SEVERAL INCHES OF SNOW POSSIBLE WITH THIS
SYSTEM. ANOTHER ARCTIC SHOT OF AIR ARRIVES FRIDAY AFTERNOON AND
SATURDAY. A WARM FRONT WILL MOVE NORTH SUNDAY.
&&
.AVIATION /20Z SUNDAY THROUGH FRIDAY/...
SHORT TERM...THERE WILL LIKELY BE A PERIOD OF HEAVY SNOW AT
SOUTHERN AND COASTAL TERMINALS FROM CONCORD TO PORTLAND TO AUGUSTA
THIS EVENING. PORTSMOUTH MAY NOT SEE THIS HEAVY SNOW AS
PRECIPITATION COULD STAY AS RAIN. EXPECT LIFR CONDITIONS FOR A
TIME BEFORE VFR RETURNS AFTER MIDNIGHT. NORTHWEST WINDS ON MONDAY
COULD GUST TO 25 KT.
LONG TERM...POSSIBLE MVFR IN SNOW SHOWERS TUESDAY AND WEDNESDAY.
IFR MOVES IN THURSDAY AFTERNOON AND MOVES OUT FRIDAY. VFR
SATURDAY AND SUNDAY.
&&
.MARINE...
SHORT TERM...LOW PRESSURE MOVING FROM CAPE COD TO NOVA SCOTIA WILL
BRING A BRIEF PERIOD OF NORTHEAST WINDS WHICH COULD GUST TO GALE
FORCE. WINDS SHIFT TO NORTHWEST BY MORNING. A COLD FRONT PUSHING
THROUGH THE GULF OF MAINE ON MONDAY WILL BRING STRONG COLD
ADVECTION AND THE POTENTIAL FOR MORE GALE FORCE GUSTS THROUGH
MONDAY EVENING.
LONG TERM...SMALL CRAFT WINDS TUESDAY AND WEDNESDAY. GALE FORCE
WINDS POSSIBLE THURSDAY AFTERNOON INTO SATURDAY MORNING.
&&
.GYX WATCHES/WARNINGS/ADVISORIES...
ME...WINTER STORM WARNING UNTIL 4 AM EST MONDAY FOR MEZ012>014-
018>022-024>028.
WINTER WEATHER ADVISORY UNTIL 4 AM EST MONDAY FOR MEZ007>009-
023.
NH...WINTER STORM WARNING UNTIL MIDNIGHT EST TONIGHT FOR NHZ004>010.
WINTER WEATHER ADVISORY UNTIL 4 AM EST MONDAY FOR NHZ002-003.
WINTER WEATHER ADVISORY UNTIL MIDNIGHT EST TONIGHT FOR NHZ013.
MARINE...SMALL CRAFT ADVISORY FROM 6 PM THIS EVENING TO 9 PM EST MONDAY
FOR ANZ151-153.
GALE WARNING FROM 6 PM THIS EVENING TO 9 PM EST MONDAY FOR
ANZ150-152-154.
&&
$$
SHORT TERM... KIMBLE
LONG TERM... HAWLEY
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
549 PM EST SUN DEC 29 2013
.SYNOPSIS...
TONIGHTS COLD FRONT PASSAGE WILL USHER IN BELOW AVERAGE TEMPERATURES
FOR THE COMING WEEK.
&&
.NEAR TERM /THROUGH MONDAY/...
EARLY EVE UPDATE WAS ISSUED TO ADJUST HOURLY TEMP AND WEA TRENDS
BASED ON OBS AND THE LATEST HRRR AND RAP MDL TRENDS.
PREVIOUS...
LOW PRES WL CONT TO MOVE OFF THE MID-ATLANTIC COAST THIS
EVE...ENDING THE STEADY RAIN. 850MB TEMPS HAVE COOLED ESP WELL N
OF PIT...AND SOME SNW COULD BRIEFLY MIX IN BEFORE THE PCPN ENDS.
COULD SEE A PD OF DRIZZLE OR LGT RAIN THIS EVE AS DEEP MOISTURE
EXITS.
A CDFNT WL MOVE THRU THE GT LKS/OH VLY RNG OVRNGT. THIS SHOULD
ALLOW FOR ENOUGH MOISTURE IN THE SNOW GROWTH RGN FOR ANY DRIZZLE
TO CHG TO SNW SHWRS AS THE FNT PASSES...PRECLUDING ANY MENTION OF
FREEZING DRIZZLE AS TEMPS FALL. SHOULD SEE UPSLOPE AND LK ENHANCED
SNW SHWRS DVLP AFT FROPA...BUT WITH LMTD MOISTURE DEPTH AND LWRG
TEMP INVERSIONS...SGFNT SNW ACCUMS ARE NOT EXPD. ANY SNW SHWRS ARE
EXPD TO GRDLY END MON AS LLVL RIDGING BLDS IN. TEMPS WL DROP IN
COLD AIR ADVCTN LTR TNGT...WITH LTL RECOVERY ON MON.
&&
.SHORT TERM /MONDAY NIGHT THROUGH WEDNESDAY NIGHT/...
A SHRTWV TROF WILL CROSS THE GRTLKS MON NGT. LOW- TO MID-LVL SWLY
FLOW WILL PROVIDE MODEST WARM AIR AND MSTR ADVCTN...LEADING TO A
BRIEF PD OF DP SATURATION THRU THE DENDRITIC GROWTH LYR. THUS... A
QUICK SHOT OF LGT SNOW WILL BE PSBL LATE MON NGT-TUE MRNG AS THIS
WAVE CROSSES THE RGN. BEST CHCS WILL BE ACRS THE NRN TWO-THIRDS OF
THE FCST AREA.
SGFNT RDG NOT XPCD BEHIND THIS WAVE AS A MORE POTENT AND BROAD
TROF DVLPS IN THE CNTRL CONUS. AS SFC LOPRES STRENGTHENS IN THE
MIDWESTERN STATES...FRONTOGENESIS XPCD TO OCCUR ALONG THE SRN
GRTLKS INTO WRN PA. WARM AIR ADVCTN AND FRONTOGENESIS SHOULD BE
SUFFICIENT TO SUPPORT A BAND OF SNOW FROM PBZ FCST AREA WWD. ANY
ACCUMS ON WED WILL BE LGT OWING TO LOW-LVL DRY AIR AND APPARENT
LACK OF DYNAMICAL FORCING FOR ASCENT.
BAND OF SNOW XPCD TO SHARPEN WED NGT WITH APRCH OF SFC LOPRES AND
INCRG FRONTOGENESIS AND UPR JET ARRIVAL CONTRIBUTING TO STRONGER
UPWD MOTION. TEMPS WED NGT SHOULD SUPPORT SNOW. KRAMAR
&&
.LONG TERM /THURSDAY THROUGH SUNDAY/...
A COUPLE CHGS WERE MADE TO THE EXTENDED ON THU AND FRI. ON THU...
SFC LOPRES XPCD TO PASS ACRS SRN PORTION OF FCST AREA...WITH
STRONG FRONTOGENESIS XPCD ALONG ARCTIC AMS BNDRY. IN COMBINATION
WITH APRCHG H5 TROF...SUFFICIENT LIFT AND DP SATURATION LKLY WILL
YIELD SNOW OR RAIN/SNOW MIX FOR MOST OF THE FCST AREA. EXACT
TIMING IS UNCERTAIN ATTM...BUT AN INCR IN POPS WAS WARRANTED.
ARCTIC AMS WILL INVADE MUCH OF FCST AREA BY THU NGT. WITH FCSTD H9
TEMPS OF 15-20C BLW ZERO IN BOTH GFS AND ECMWF AND SUPPORTED BY
NAEFS...IT IS VERY DIFFICULT TO SEE HOW MAXIMA WILL RISE OUT OF
THE TEENS. MAXIMA WERE LWRD ON FRI TO REFLECT THIS FCST. PREV
DISCUSSION FOLLOWS... KRAMAR
STILL LOTS TO BE WORKED OUT WITH MODEL SOLUTIONS CONCERNING AN
OVERRUNNING SETUP BY THE MIDDLE OF NEXT WEEK. TEMPS WILL REMAIN
BELOW NORMAL THROUGH THE PERIOD...WITH THE COLDEST AIR EXPECTED BY
THE END OF THE LONG TERM.
&&
.AVIATION /00Z MONDAY THROUGH FRIDAY/...
LOW PRES MOVG ACRS THE MD ATLANTIC WL BRING MVFR TO IFR CONDS IN
RAIN THRU ERLY EVE. THE RAIN WL TAPER OFF LT THIS AFTN BUT MVFR
CIGS ARE EXPD TO REMAIN. A CDFNT WL CROSS THE RGN TNGT WITH A FEW
SNW SHWRS AND MVFR CONDS CONTG. LGT WNDS WL SHIFT TO THE W LT THIS
AFTN AS THE SFC LOW PASSES TO OUR E.
.OUTLOOK.../MONDAY NIGHT THROUGH FRIDAY/...
PERIODIC RSTRNS ARE EXPD THRU LT WK AS SVRL DISTURBANCES CROSS THE
RGN.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
OH...NONE.
PA...NONE.
WV...NONE.
&&
$$
15
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
426 PM EST SUN DEC 29 2013
.SHORT TERM...(THIS EVENING THROUGH MONDAY)
ISSUED AT 424 PM EST SUN DEC 29 2013
ARCTIC AIR AND CONTINUED LAKE EFFECT OFF LAKE SUPERIOR WILL BE THE
MAIN CONCERNS FOR THE SHORT TERM PERIOD.
THE SURFACE LOW THAT BROUGHT THE SURGE OF COLD AIR CONTINUES TO
SLIDE EAST OF THE AREA...WHILE HIGH PRESSURE HAS BUILT INTO THE
NORTHERN PLAINS AND UPPER MISSISSIPPI VALLEY. THE EXITING LOW HAS
LEFT A SURFACE TROUGH OVER EASTERN LAKE SUPERIOR. ALOFT...AREA IS
UNDER AN UPPER TROUGH THAT COVERS MUCH OF THE EASTERN CONUS AND HAS
LED TO ARCTIC AIR SPILLING SOUTHEAST OVER THE UPPER GREAT LAKES LAST
NIGHT. THIS COLD AIR HAS BEEN PRODUCING LAKE EFFECT SNOW SHOWERS IN
THE NORTH-NORTHWEST WIND LOCATIONS TODAY. LATEST RADAR/SATELLITE
DATA INDICATES THE BEST BANDS OVER FAR EASTERN MARQUETTE COUNTY
AND ALGER COUNTIES...WHERE RADAR RETURNS HAVE BEEN REACHING
7KFT. HAVE STARTED SEEING THE LOW LEVEL WINDS BACKING ASSOCIATED
WITH THE HIGH PRESSURE RIDGE OVER THE LAST FEW HOURS...ESPECIALLY
OVER THE WESTERN LAKE...AND THAT HAS STARTED TO PUSH THE BANDS OVER
MARQUETTE COUNTY EASTWARD. WITH AT LEAST HALF OF THE CLOUD BEING
ABOVE THE DGZ BASED ON RAP INITIAL SOUNDINGS...CALLS TO SPOTTERS
HAS INDICATED JUST A COUPLE INCHES OF ADDITIONAL SNOW
ACCUMULATION TODAY. THE BIGGEST ISSUE HAS BEEN THE SMALL FLAKES
REDUCING VISIBILITIES...ALONG WITH GUSTY WINDS TO 30-35MPH EAST
OF MARQUETTE...AND CAUSING BRIEF WHITEOUTS ALONG M-28 IN ALGER
COUNTY. A CALL TO THE ALGER COUNTY SHERIFF INDICATED SEVERAL
ACCIDENTS ON THAT STRETCH...WITH THEM ENCOURAGING TRAVEL ALONG
M-94 INSTEAD.
WITH THE COLD AIR IN PLACE AND SOME LOW LEVEL MOISTURE...EXPECT THE
LAKE EFFECT TO CONTINUE THROUGH THE SHORT TERM PERIOD. THE
LOCATION OF THE SNOW WILL BE DETERMINED BY BOUNDARY LAYER WINDS.
SINCE THE HIGH OVER SOUTHEAST SOUTH DAKOTA WILL DRIFT TO THE
SOUTHEAST THROUGH THE NIGHT...IT WILL PUSH A RIDGE INTO THE
SOUTHWEST HALF OF UPPER MICHIGAN. THIS RIDGE WILL DO TWO
THINGS...BACK THE WINDS TO MORE OF A WEST-NORTHWEST DIRECTION AND
CONTINUE TO PROVIDE DRY AIR AND SUBSIDENCE ABOVE 850MB. THOSE
BACKING WINDS WILL ALSO BE AIDED BY A SHORTWAVE DEPARTING THE
CANADIAN ROCKIES AND MOVING INTO THE NORTHERN PLAINS ON
MONDAY. THIS WILL LEAD TO WINDS TRANSITIONING FROM THE
NORTH-NORTHWEST LATE THIS AFTERNOON TO THE NORTHWEST THIS EVENING
AND EVENTUALLY NEARLY WESTERLY BY 18Z MONDAY. THEREFORE...WOULD
EXPECT THE PURE LAKE EFFECT BANDS (NO SHORTWAVE HELP) TO FOLLOW
SUIT. 850MB TEMPS WILL REMAIN FAIRLY STEADY THROUGH MONDAY AND
AROUND -23C...LEADING TO DELTA-T VALUES AROUND THE MID 20S. BUT
THIS COLD AIR WILL LEAD TO MUCH OF THE CLOUD BEING AT THE HIGH END
OF THE DGZ OR ABOVE IT...SO WOULD EXPECT SNOW RATIOS TO BE ON THE
LOWER END FOR LAKE EFFECT AND IN MOST SITUATIONS BELOW 20 TO 1. IN
THE STRONGEST BANDS OVER THE EAST AND THE BETTER LAKE
MODIFICATION...DID KEEP SOME LOW 20S IN THE FORECAST. AS SEEN ON
SATELLITE NEAR IRONWOOD THIS AFTERNOON...THE STRONGEST BANDS
WILL BE ON THE SOUTHWEST EDGE OF THE LES DUE TO THE ENHANCED
CONVERGENCE FROM THE BACKING WINDS. ALTHOUGH THIS WILL STRENGTHEN
THE BANDS...THINK THE CONSISTENT BACKING FLOW (ALONG WITH THE LOWER
RATIOS) WILL BE ENOUGH TO KEEP AMOUNTS GENERALLY LIGHT. HAVE KEPT
AMOUNTS FAIRLY SIMILAR TO WHAT WAS SEEN DURING THE DAY TODAY IN THE
LES LOCATIONS (1-2.5IN)...BUT DO HAVE SLIGHTLY HIGHER AMOUNTS
(APPROACHING 4) OVER THE EAST WITH THE SLOWER BACKING TREND. THE
LONGER FETCH WITH THE WEST TO WEST-SOUTHWEST WINDS OVER WESTERN
LAKE SUPERIOR COULD LEAD TO AN INCREASE IN INTENSITY OF THE MAIN
LAKE EFFECT BAND OVER THE KEWEENAW PENINSULA (NORTH OF HOUGHTON).
LAKE INDUCED EQUILIBRIUM LEVELS STILL AROUND 7KFT AND MUCH OF THE
CLOUDS IS AT HIGH END OF DGZ OR ABOVE SO WON/T GO TOO HIGH ON
AMOUNTS IN THE LATE MORNING AND INTO THE AFTERNOON...BUT COULD NEAR
LOW END ADVISORY AMOUNTS.
AS FOR SNOW HEADLINES...CANCELLED BARAGA AND SOUTHERN HOUGHTON
EARLY AND WILL ALLOW THE REST OF THE WESTERN AREAS EXPIRE AT 00Z AS
WINDS WILL DIMINISH AND JUST LIGHT SNOW WILL REMAIN. OVER THE
EAST...HAVE KEPT THEM AS IS WITH THE BAD CONDITIONS REPORTED ALONG
M-28 IN ALGER COUNTY...ALTHOUGH MOST LOCATIONS TONIGHT WILL
STRUGGLE TO REACH THE 4 INCH IN 12HR AMOUNTS DUE TO THE SMALLER
FLAKES.
AS FOR THE WIND CHILL HEADLINES...CLOUDS WILL DETERMINE THE LOWS
TONIGHT. UNFORTUNATELY IT COMES DOWN TO THE DIMINISHING LAKE
EFFECT CLOUDS OVER THE WEST AND THEN HIGH CLOUDS STREAMING IN LATE
TONIGHT AHEAD OF THE NEXT WAVE IN THE UPPER TROUGH SLIDING SOUTHEAST
THROUGH THE NORTHERN PLAINS. 12Z GFS/ECMWF ARE THE MOST AGGRESSIVE
WITH THESE HIGH CLOUD...COVERING THE WESTERN HALF OF THE CWA BY
12Z. WITH THE COLD AIR IN PLACE...THINK THAT TEMPS WILL COOL
FAIRLY QUICKLY IN AREAS THAT SKIES CLEAR. THE REGIONAL
GEM...WHICH TRADITIONALLY DOES WELL IN THESE CASES ONLY HAS LOWS
IN THE LOW TEENS BELOW ZERO ALONG THE WISCONSIN BORDER AND SINGLE
DIGITS ELSEWHERE. THIS PROVIDES SOME CONCERN TO THE GOING FORECAST
AND TWEAKED VALUES SLIGHTLY HIGHER. ON THE OTHER SIDE...18Z HRRR/RAP
FORECASTS HAVE LOWS AROUND -20 TO -23 TONIGHT...BUT IN MOST
SITUATIONS THEY ARE TOO LOW. EVEN WITH THE SLIGHT TWEAKS...WIND
CHILL ADVISORY LOOKS GOOD FOR AREAS NEAR THE WISCONSIN BORDER AND
HAVE LEFT IT AS IS. A LITTLE CONCERNED ON LAKE CLOUDS LINGERING
OVER MARQUETTE/BARAGA...BUT LOCATIONS WELL INLAND SHOULD CLEAR OUT
LATE AND ALLOW FOR TEMPS TO FALL. FINALLY...MAY NEED TO MONITOR
MENOMINEE COUNTY...AS GOING FORECAST HAS WIND CHILLS NEARING -25
OVER THE WESTERN REACHES OF THE COUNTY.
THE PREVIOUSLY MENTIONED MID/HIGH CLOUDS WILL MOVE ACROSS THE REST
OF THE CWA DURING THE DAY ON MONDAY AND LEAD TO A FILTERED SUNSHINE
AWAY FROM THE LAKE EFFECT. THERE COULD EVEN BE A FEW SNOW SHOWERS
NEAR IRONWOOD LATE MONDAY AFTERNOON ON THE NORTH EDGE OF THE WAVE
MOVING INTO WISCONSIN ON MONDAY EVENING. HIGHS ON MONDAY WILL BE
15-20 DEGREES BELOW NORMAL AND IN THE SINGLE DIGITS ABOVE ZERO FOR
MOST LOCATIONS.
.LONG TERM...(MONDAY NIGHT THROUGH SUNDAY)
ISSUED AT 425 PM EST SUN DEC 29 2013
BIGGEST CONCERNS IN THE EXTENDED FOCUS ON THE POTENTIAL FOR HEAVY
LAKE EFFECT SNOW OVER THE NE CWA MON NIGHT INTO TUESDAY AND ALSO
ADVISORY LEVEL WIND CHILLS FOR SOME AREAS INTO MIDWEEK.
MON NIGHT INTO TUE...AS THE POLAR VORTEX SLOWLY SHIFTS SE FROM
HUDSON BAY...THE MODELS SUGGEST A SHORTWAVE TROUGH WILL MOVE THROUGH
THE UPPER MS VALLEY TOWARD THE UPPER GREAT LAKES. THE BEST ISENTROPIC
LIFT NEAR THE 850 MB FRONT AND POTENTIAL FOR WIDESPREAD LIGHT SNOW
IS EXPECTED TO REMAIN TO THE SOUTH OF UPPER MI. AS THE LOW LEVEL
WINDS BACK W OR WSW AHEAD OF THE SHRTWV ON MONDAY...THE LES OVER THE
NE CWA WILL GRADUALLY LIFT TO THE NORTH AND POSSIBLY MOVE OFFSHORE
BY LATE IN THE DAY. VEERING WINDS IN THE WAKE OF THE SHRTWV WILL
PUSH THE LES BACK INTO AREAS FAVORED BY NW FLOW BY LATE EVENING.
LAKE INDUCED TROUGHING IS EXPECTED TO FOCUS THE STRONGEST LOW LEVEL
CONV BACK INTO THE NE PORTION OF THE CWA FROM P53 EASTWARD. NAM FCST
SOUNDINGS ALSO INDICATE THAT THE DGZ WILL BE MORE FAVORABLY PLACED
IN THE CONVECTIVE LAYER TO BOOST SLR VALUES AND OVERALL SNOWFALL
POTENTIAL. USING A BLEND OF THE NAM AND LOCAL WRF-ARW QPF WITH
LIKELY CONSERVATIVE SLR VALUES AROUND 20/1...CAME UP WITH TOTAL
SNOWFALL ACCUMULATION EXCEEDING A FOOT OVER ERN ALGER AND NRN LUCE
COUNTIES FOR THE MON NIGHT THROUGH TUE TIME FRAME. THUS...HAVE
DECIDED TO ISSUE A LAKE EFFECT SNOW WATCH FOR ALGER AND LUCE
COUNTIES OVER THIS TIME FRAME. NRN SCHOOLCRAFT WILL LIKELY SEE
PERIODS OF HEAVY LES AS WELL...BUT LOW-LVL CONVERGENCE WILL NOT BE
AS PERSISTENT THERE SO WILL KEEP THEM OUT OF THE WATCH...BUT FEEL
PRETTY CERTAIN THEY WILL EVENTUALLY NEED AN LES ADVISORY.
EVEN THOUGH TEMPS MAY NOT BE AS COLD EARLY TUE...SLIGHTLY STRONGER
WINDS IN THE WAKE OF THE SHORTWAVE WILL AGAIN PUSH WIND CHILLS INTO
THE -25 TO -35 ADVISORY RANGE OVER THE WEST.
WED INTO THU...THE NEXT SIGNIFICANT SHORTWAVE TROUGH IS EXPECTED TO
REMAIN WELL TO THE SOUTH BRINGING SNOW TO MAINLY IA/NRN IL/SRN WI
AND THE SOUTHERN GREAT LAKES. GREAT LAKES AGGREGATE TROUGHING WILL
INFLUENCE GENERALLY LIGHT LOW LEVEL WIND FIELDS AND THE RESULTING LES
INTO UPPER MI AS 850 MB TEMPS REMAIN IN THE -22C TO -26C RANGE. IT
APPEARS NOW THE MAIN FOCUS FOR LES ACCUMULATIONS MAY BE OVER THE
WEST AND NCNTRL PORTIONS OF THE CWA AS A N-NE FLOW IS EXPECTED TO
DEVELOP WED NIGHT INTO THU ON THE BACKSIDE OF SFC LOW PASSING SOUTH
AND THEN EAST OF THE REGION. WITH MODEL SNDGS SHOWING COMPRESSION OF
THE DGZ WITHIN THE LOWEST 2KFT OF THE ATMOSPHERE ALONG WITH
INVERSION HGTS AROUND 5 KFT...THE EXPECTED SMALLER FLAKE SIZE SHOULD
GENERALLY KEEP ACCUMULATION LIGHT FOR THE MOST PART.
FRI-SUN...MODELS WERE IN GENERAL AGREEMENT WITH TREND TOWARD A LESS
AMPLIFIED PATTERN. AS SFC HIGH PRESSURE SLIDES EAST LATE IN THE
WEEK...THE ECMWF AND GFS DEVELOP AREA OF LIGHT SNOW IN REGION OF
WAA/ISENTROPIC ASCENT AHEAD OF A SHRTWV MOVING THROUGH NW ONTARIO.
THIS SNOW LOOKS TO SPREAD INTO UPPER MI LATE FRI INTO SAT MORNING
WITH ANOTHER BAND OF SYNOPTIC SNOW ALONG COLD FRONTAL PASSAGE SAT
AFTERNOON/SAT NIGHT. EXPECT LES TO DEVELOP LATE SATURDAY NIGHT INTO
SUNDAY WITH INCREASING CAA IN NNW FLOW IN THE WAKE OF THE COLD
FRONT.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY AFTERNOON)
ISSUED AT 1243 PM EST SUN DEC 29 2013
ARCTIC AIR MOVING SOUTHEAST ACROSS LAKE SUPERIOR WILL CONTINUE TO
PRODUCE LAKE EFFECT SNOW THIS AFTERNOON AT ALL THREE TAF SITES. THE
SITES SHOULD LARGELY STAY AT ALTERNATE LANDING MIN VISIBILITIES
FOR THE NEXT SEVERAL HOURS...BUT COULD SEE BRIEF FLUCTUATIONS UP
AND DOWN AS THE BANDS MOVE THROUGH. THEN...AS A HIGH PRESSURE RIDGE
BEGINS TO MOVE INTO WESTERN LAKE SUPERIOR LATER THIS AFTERNOON AND
TONIGHT...THE BACKING WINDS WILL SHIFT THE LAKE EFFECT AWAY FROM
KIWD/KSAW (AND CONDITIONS IMPROVING TO VFR)...ALTHOUGH IT WILL
REMAIN FOCUSED AT KCMX. THERE WILL LIKELY BE A STRONGER BAND
AFFECTING KCMX LATE TONIGHT INTO MONDAY MORNING AND WITH THE FINER
FLAKES...EXPECT THE VISIBILITIES TO BE SIMILAR TO TODAY EVEN WITH
LESS WIND. CONFIDENCE WAS LOW ON HOW FAR NORTH THE BAND WILL SHIFT
ACROSS THE KEWEENAW PENINSULA LATER MONDAY MORNING...SO HAVE
LINGERED MVFR CONDITIONS THROUGH THE END OF THE TAF PERIOD.
&&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 424 PM EST SUN DEC 29 2013
NORTHWESTERLY WINDS OF 15 TO 25 KNOTS WILL CONTINUE INTO THIS
EVENING BEFORE BACKING TO THE WEST-NORTHWEST LATE TONIGHT INTO
MONDAY. WINDS WILL WEAKEN SLIGHTLY AS THIS OCCURS AND SLOWLY
DIMINISH THE POTENTIAL FOR FREEZING SPRAY OVER THE LAKE BY MONDAY
AFTERNOON. AS THE LINGERING SURFACE TROUGH OVER EASTERN LAKE
SUPERIOR STRENGTHENS ON MONDAY NIGHT AND SHIFTS EAST ON
TUESDAY...NORTHWESTERLY WINDS WILL INCREASE WITH SOME GUSTS TO 30KTS
OVER THE EASTERN LAKE TUESDAY AFTERNOON AND EVENING. THIS WILL ALSO
BRING AN INCREASED OPPORTUNITY FOR HEAVY FREEZING SPRAY THROUGH
TUESDAY NIGHT OVER THE EASTERN HALF OF LAKE SUPERIOR. ALTHOUGH
THERE STILL WILL BE A LINGERING TROUGH OVER EASTERN LAKE SUPERIOR
INTO WEDNESDAY...HIGH PRESSURE BUILDING OVER THE UPPER MISSISSIPPI
VALLEY WILL LEAD TO LIGHTER NORTHWESTERLY WINDS FOR WEDNESDAY AND
THURSDAY...BRINGING AN END TO THE POTENTIAL FOR HEAVY FREEZING
SPRAY.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
WIND CHILL ADVISORY FROM MIDNIGHT EST /11 PM CST/ TONIGHT TO 10
AM EST /9 AM CST/ MONDAY FOR MIZ011-084.
LAKE EFFECT SNOW ADVISORY UNTIL 7 AM EST MONDAY FOR MIZ085.
LAKE EFFECT SNOW ADVISORY UNTIL 7 PM EST /6 PM CST/ THIS EVENING
FOR MIZ001>003-005-009.
WIND CHILL ADVISORY UNTIL 10 AM EST /9 AM CST/ MONDAY FOR MIZ002-
009-010.
LAKE EFFECT SNOW ADVISORY UNTIL 1 PM EST MONDAY FOR MIZ006-007.
LAKE EFFECT SNOW WATCH FROM MONDAY EVENING THROUGH TUESDAY
EVENING FOR MIZ006-007.
WIND CHILL ADVISORY FROM 4 AM TO 10 AM EST MONDAY FOR MIZ004-005.
LAKE SUPERIOR...
HEAVY FREEZING SPRAY WARNING UNTIL 1 AM EST WEDNESDAY FOR LSZ267.
HEAVY FREEZING SPRAY WARNING UNTIL 7 AM EST WEDNESDAY FOR LSZ266.
HEAVY FREEZING SPRAY WARNING UNTIL 1 PM EST MONDAY FOR LSZ265.
HEAVY FREEZING SPRAY WARNING UNTIL 7 AM EST MONDAY FOR LSZ248-
249-264.
HEAVY FREEZING SPRAY WARNING UNTIL 1 AM EST MONDAY FOR LSZ263.
HEAVY FREEZING SPRAY WARNING UNTIL 7 PM EST /6 PM CST/ THIS
EVENING FOR LSZ162-240>247.
HEAVY FREEZING SPRAY WARNING UNTIL 6 PM EST MONDAY FOR LSZ250-
251.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...SRF
LONG TERM...VOSS
AVIATION...SRF
MARINE...SRF
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
424 PM EST SUN DEC 29 2013
.SHORT TERM...(THIS EVENING THROUGH MONDAY)
ISSUED AT 424 PM EST SUN DEC 29 2013
ARCTIC AIR AND CONTINUED LAKE EFFECT OFF LAKE SUPERIOR WILL BE THE
MAIN CONCERNS FOR THE SHORT TERM PERIOD.
THE SURFACE LOW THAT BROUGHT THE SURGE OF COLD AIR CONTINUES TO
SLIDE EAST OF THE AREA...WHILE HIGH PRESSURE HAS BUILT INTO THE
NORTHERN PLAINS AND UPPER MISSISSIPPI VALLEY. THE EXITING LOW HAS
LEFT A SURFACE TROUGH OVER EASTERN LAKE SUPERIOR. ALOFT...AREA IS
UNDER AN UPPER TROUGH THAT COVERS MUCH OF THE EASTERN CONUS AND HAS
LED TO ARCTIC AIR SPILLING SOUTHEAST OVER THE UPPER GREAT LAKES LAST
NIGHT. THIS COLD AIR HAS BEEN PRODUCING LAKE EFFECT SNOW SHOWERS IN
THE NORTH-NORTHWEST WIND LOCATIONS TODAY. LATEST RADAR/SATELLITE
DATA INDICATES THE BEST BANDS OVER FAR EASTERN MARQUETTE COUNTY
AND ALGER COUNTIES...WHERE RADAR RETURNS HAVE BEEN REACHING
7KFT. HAVE STARTED SEEING THE LOW LEVEL WINDS BACKING ASSOCIATED
WITH THE HIGH PRESSURE RIDGE OVER THE LAST FEW HOURS...ESPECIALLY
OVER THE WESTERN LAKE...AND THAT HAS STARTED TO PUSH THE BANDS OVER
MARQUETTE COUNTY EASTWARD. WITH AT LEAST HALF OF THE CLOUD BEING
ABOVE THE DGZ BASED ON RAP INITIAL SOUNDINGS...CALLS TO SPOTTERS
HAS INDICATED JUST A COUPLE INCHES OF ADDITIONAL SNOW
ACCUMULATION TODAY. THE BIGGEST ISSUE HAS BEEN THE SMALL FLAKES
REDUCING VISIBILITIES...ALONG WITH GUSTY WINDS TO 30-35MPH EAST
OF MARQUETTE...AND CAUSING BRIEF WHITEOUTS ALONG M-28 IN ALGER
COUNTY. A CALL TO THE ALGER COUNTY SHERIFF INDICATED SEVERAL
ACCIDENTS ON THAT STRETCH...WITH THEM ENCOURAGING TRAVEL ALONG
M-94 INSTEAD.
WITH THE COLD AIR IN PLACE AND SOME LOW LEVEL MOISTURE...EXPECT THE
LAKE EFFECT TO CONTINUE THROUGH THE SHORT TERM PERIOD. THE
LOCATION OF THE SNOW WILL BE DETERMINED BY BOUNDARY LAYER WINDS.
SINCE THE HIGH OVER SOUTHEAST SOUTH DAKOTA WILL DRIFT TO THE
SOUTHEAST THROUGH THE NIGHT...IT WILL PUSH A RIDGE INTO THE
SOUTHWEST HALF OF UPPER MICHIGAN. THIS RIDGE WILL DO TWO
THINGS...BACK THE WINDS TO MORE OF A WEST-NORTHWEST DIRECTION AND
CONTINUE TO PROVIDE DRY AIR AND SUBSIDENCE ABOVE 850MB. THOSE
BACKING WINDS WILL ALSO BE AIDED BY A SHORTWAVE DEPARTING THE
CANADIAN ROCKIES AND MOVING INTO THE NORTHERN PLAINS ON
MONDAY. THIS WILL LEAD TO WINDS TRANSITIONING FROM THE
NORTH-NORTHWEST LATE THIS AFTERNOON TO THE NORTHWEST THIS EVENING
AND EVENTUALLY NEARLY WESTERLY BY 18Z MONDAY. THEREFORE...WOULD
EXPECT THE PURE LAKE EFFECT BANDS (NO SHORTWAVE HELP) TO FOLLOW
SUIT. 850MB TEMPS WILL REMAIN FAIRLY STEADY THROUGH MONDAY AND
AROUND -23C...LEADING TO DELTA-T VALUES AROUND THE MID 20S. BUT
THIS COLD AIR WILL LEAD TO MUCH OF THE CLOUD BEING AT THE HIGH END
OF THE DGZ OR ABOVE IT...SO WOULD EXPECT SNOW RATIOS TO BE ON THE
LOWER END FOR LAKE EFFECT AND IN MOST SITUATIONS BELOW 20 TO 1. IN
THE STRONGEST BANDS OVER THE EAST AND THE BETTER LAKE
MODIFICATION...DID KEEP SOME LOW 20S IN THE FORECAST. AS SEEN ON
SATELLITE NEAR IRONWOOD THIS AFTERNOON...THE STRONGEST BANDS
WILL BE ON THE SOUTHWEST EDGE OF THE LES DUE TO THE ENHANCED
CONVERGENCE FROM THE BACKING WINDS. ALTHOUGH THIS WILL STRENGTHEN
THE BANDS...THINK THE CONSISTENT BACKING FLOW (ALONG WITH THE LOWER
RATIOS) WILL BE ENOUGH TO KEEP AMOUNTS GENERALLY LIGHT. HAVE KEPT
AMOUNTS FAIRLY SIMILAR TO WHAT WAS SEEN DURING THE DAY TODAY IN THE
LES LOCATIONS (1-2.5IN)...BUT DO HAVE SLIGHTLY HIGHER AMOUNTS
(APPROACHING 4) OVER THE EAST WITH THE SLOWER BACKING TREND. THE
LONGER FETCH WITH THE WEST TO WEST-SOUTHWEST WINDS OVER WESTERN
LAKE SUPERIOR COULD LEAD TO AN INCREASE IN INTENSITY OF THE MAIN
LAKE EFFECT BAND OVER THE KEWEENAW PENINSULA (NORTH OF HOUGHTON).
LAKE INDUCED EQUILIBRIUM LEVELS STILL AROUND 7KFT AND MUCH OF THE
CLOUDS IS AT HIGH END OF DGZ OR ABOVE SO WON/T GO TOO HIGH ON
AMOUNTS IN THE LATE MORNING AND INTO THE AFTERNOON...BUT COULD NEAR
LOW END ADVISORY AMOUNTS.
AS FOR SNOW HEADLINES...CANCELLED BARAGA AND SOUTHERN HOUGHTON
EARLY AND WILL ALLOW THE REST OF THE WESTERN AREAS EXPIRE AT 00Z AS
WINDS WILL DIMINISH AND JUST LIGHT SNOW WILL REMAIN. OVER THE
EAST...HAVE KEPT THEM AS IS WITH THE BAD CONDITIONS REPORTED ALONG
M-28 IN ALGER COUNTY...ALTHOUGH MOST LOCATIONS TONIGHT WILL
STRUGGLE TO REACH THE 4 INCH IN 12HR AMOUNTS DUE TO THE SMALLER
FLAKES.
AS FOR THE WIND CHILL HEADLINES...CLOUDS WILL DETERMINE THE LOWS
TONIGHT. UNFORTUNATELY IT COMES DOWN TO THE DIMINISHING LAKE
EFFECT CLOUDS OVER THE WEST AND THEN HIGH CLOUDS STREAMING IN LATE
TONIGHT AHEAD OF THE NEXT WAVE IN THE UPPER TROUGH SLIDING SOUTHEAST
THROUGH THE NORTHERN PLAINS. 12Z GFS/ECMWF ARE THE MOST AGGRESSIVE
WITH THESE HIGH CLOUD...COVERING THE WESTERN HALF OF THE CWA BY
12Z. WITH THE COLD AIR IN PLACE...THINK THAT TEMPS WILL COOL
FAIRLY QUICKLY IN AREAS THAT SKIES CLEAR. THE REGIONAL
GEM...WHICH TRADITIONALLY DOES WELL IN THESE CASES ONLY HAS LOWS
IN THE LOW TEENS BELOW ZERO ALONG THE WISCONSIN BORDER AND SINGLE
DIGITS ELSEWHERE. THIS PROVIDES SOME CONCERN TO THE GOING FORECAST
AND TWEAKED VALUES SLIGHTLY HIGHER. ON THE OTHER SIDE...18Z HRRR/RAP
FORECASTS HAVE LOWS AROUND -20 TO -23 TONIGHT...BUT IN MOST
SITUATIONS THEY ARE TOO LOW. EVEN WITH THE SLIGHT TWEAKS...WIND
CHILL ADVISORY LOOKS GOOD FOR AREAS NEAR THE WISCONSIN BORDER AND
HAVE LEFT IT AS IS. A LITTLE CONCERNED ON LAKE CLOUDS LINGERING
OVER MARQUETTE/BARAGA...BUT LOCATIONS WELL INLAND SHOULD CLEAR OUT
LATE AND ALLOW FOR TEMPS TO FALL. FINALLY...MAY NEED TO MONITOR
MENOMINEE COUNTY...AS GOING FORECAST HAS WIND CHILLS NEARING -25
OVER THE WESTERN REACHES OF THE COUNTY.
THE PREVIOUSLY MENTIONED MID/HIGH CLOUDS WILL MOVE ACROSS THE REST
OF THE CWA DURING THE DAY ON MONDAY AND LEAD TO A FILTERED SUNSHINE
AWAY FROM THE LAKE EFFECT. THERE COULD EVEN BE A FEW SNOW SHOWERS
NEAR IRONWOOD LATE MONDAY AFTERNOON ON THE NORTH EDGE OF THE WAVE
MOVING INTO WISCONSIN ON MONDAY EVENING. HIGHS ON MONDAY WILL BE
15-20 DEGREES BELOW NORMAL AND IN THE SINGLE DIGITS ABOVE ZERO FOR
MOST LOCATIONS.
.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 455 AM EST SUN DEC 29 2013
MON INTO TUE...AS THE POLAR VORTEX SLOWLY SHIFTS SE FROM HUDSON
BAY...THE MODELS SUGGEST A SHORTWAVE TROUGH WILL MOVE THROUGH THE
UPPER MS VALLY TOWARD THE WRN GREAT LAKES. THE BEST ISENTROPIC LIFT
NEAR THE 850 MB FRONT AND POTENTIAL FOR WIDESPREAD LIGHT SNOW IS
EXPECTED TO REMAIN TO THE SOUTH OF UPPER MI. AS THE LOW LEVEL WINDS
BACK AHEAD OF THE SHRTWV...THE LES OVER THE NE CWA WILL GRADUALLY
LIFT TO THE NORTH AND POSSIBLY MOVE OFFSHORE BY LATE IN THE DAY.
ADDITIONAL SNOWFALL AMOUNTS IN THE MORNING MAY AMOUNT TO 1 TO 3
INCHES OVER FAR ERN ALGER COUNTY AND NRN LUCE COUNTY. OVER THE
WEST...CONVERGENT WRLY FLOW WILL LIKELY BRING AN INCREASE IN LES
INTENSITY OVER THE KEWEENAW. ALTHOUGH ADVY SNOWFALL AMOUNTS IN THE 2
TO 6 INCH RANGE MAY BE POSSIBLE...CONFIDENCE IN THE LOW LEVEL WIND
DETAILS IS LIMITED. VEERING WINDS IN THE WAKE OF THE SHRTWV WILL
PUSH THE LES BACK INTO AREAS FAVORED BY NW FLOW. LAKE INDUCED
TROUGHING IS EXPECTED TO FOCUS THE STRONGEST LOW LEVEL CONV BACK INTO
THE NE PORTION OF THE CWA FROM P53 EASTWARD. NAM FCST SOUNDINGS
ALSO SUGGEST THAT THE DGZ WILL BE MORE FAVORABLY PLACED IN THE
CONVECTIVE LAYER TO BOOST SLR VALUES AND OVERALL SNOWFALL
POTENTIAL.
WIND CHILL VALUES INTO THE ADVISORY RANGE FROM -25 TO -35 EARLY
MONDAY OVER THE INTERIOR WEST WILL MODERATE BY MID MORNING WITH DIURNAL
WARMING AND DIMINISHING WINDS. EVEN THOUGH TEMPS MAY NOT BE AS COLD
EARLY TUE...SLIGHTLY STRONGER WINDS WILL AGAIN PUSH WIND CHILLS INTO
THE -25 TO -35 ADVY RANGE OVER THE WEST.
WED INTO THU...THE NEXT SIGNIFICANT SHORTWAVE TROUGH IS EXPECTED TO
REMAIN WELL TO THE SOUTH BRINGING SNOW TO MAINLY IA/NRN IL/SRN WI
AND THE SOUTHERN GREAT LAKES. GREAT LAKES AGGREGATE TROUGHING WILL
INFLUENCE GENERALLY LIGHT LOW LEVEL WIND FIELDS AND THE RESULTING LES
INTO UPPER MI AS 850 MB TEMPS REMAIN IN THE -22C TO -26C RANGE. ALTHOUGH
THE MAIN FOCUS FOR HIGHER LES ACCUMULATIONS WILL REMAIN OVER THE ERN
CWA...AT LEAST LIGHT LES WILL PERSIST OVER THE WEST THROUGH THE
PERIOD.
FRI-SAT...MODELS WERE IN GENERAL AGREEMENT WITH TREND TOWARD A LESS
AMPLIFIED PATTERN. AS SFC HIGH PRESSURE SLIDES EAST LATE IN THE
WEEK...THE ECMWF AND GFS DEVELOP AREA OF LIGHT SNOW IN REGION OF
WAA/ISENTROPIC ASCENT AHEAD OF A SHRTWV MOVING INTO NW ONTARIO. THIS
SNOW LOOKS TO SPREAD INTO UPPER MI LATE FRI OR FRI NIGHT. AS SYSTEM
SNOW TAPERS OFF EARLY SAT...LES COULD DEVELOP LATE IN THE DAY AS
WINDS SHIFT TO THE NW BEHIND FRONTAL PASSAGE.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY AFTERNOON)
ISSUED AT 1243 PM EST SUN DEC 29 2013
ARCTIC AIR MOVING SOUTHEAST ACROSS LAKE SUPERIOR WILL CONTINUE TO
PRODUCE LAKE EFFECT SNOW THIS AFTERNOON AT ALL THREE TAF SITES. THE
SITES SHOULD LARGELY STAY AT ALTERNATE LANDING MIN VISIBILITIES
FOR THE NEXT SEVERAL HOURS...BUT COULD SEE BRIEF FLUCTUATIONS UP
AND DOWN AS THE BANDS MOVE THROUGH. THEN...AS A HIGH PRESSURE RIDGE
BEGINS TO MOVE INTO WESTERN LAKE SUPERIOR LATER THIS AFTERNOON AND
TONIGHT...THE BACKING WINDS WILL SHIFT THE LAKE EFFECT AWAY FROM
KIWD/KSAW (AND CONDITIONS IMPROVING TO VFR)...ALTHOUGH IT WILL
REMAIN FOCUSED AT KCMX. THERE WILL LIKELY BE A STRONGER BAND
AFFECTING KCMX LATE TONIGHT INTO MONDAY MORNING AND WITH THE FINER
FLAKES...EXPECT THE VISIBILITIES TO BE SIMILAR TO TODAY EVEN WITH
LESS WIND. CONFIDENCE WAS LOW ON HOW FAR NORTH THE BAND WILL SHIFT
ACROSS THE KEWEENAW PENINSULA LATER MONDAY MORNING...SO HAVE
LINGERED MVFR CONDITIONS THROUGH THE END OF THE TAF PERIOD.
&&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 424 PM EST SUN DEC 29 2013
NORTHWESTERLY WINDS OF 15 TO 25 KNOTS WILL CONTINUE INTO THIS
EVENING BEFORE BACKING TO THE WEST-NORTHWEST LATE TONIGHT INTO
MONDAY. WINDS WILL WEAKEN SLIGHTLY AS THIS OCCURS AND SLOWLY
DIMINISH THE POTENTIAL FOR FREEZING SPRAY OVER THE LAKE BY MONDAY
AFTERNOON. AS THE LINGERING SURFACE TROUGH OVER EASTERN LAKE
SUPERIOR STRENGTHENS ON MONDAY NIGHT AND SHIFTS EAST ON
TUESDAY...NORTHWESTERLY WINDS WILL INCREASE WITH SOME GUSTS TO 30KTS
OVER THE EASTERN LAKE TUESDAY AFTERNOON AND EVENING. THIS WILL ALSO
BRING AN INCREASED OPPORTUNITY FOR HEAVY FREEZING SPRAY THROUGH
TUESDAY NIGHT OVER THE EASTERN HALF OF LAKE SUPERIOR. ALTHOUGH
THERE STILL WILL BE A LINGERING TROUGH OVER EASTERN LAKE SUPERIOR
INTO WEDNESDAY...HIGH PRESSURE BUILDING OVER THE UPPER MISSISSIPPI
VALLEY WILL LEAD TO LIGHTER NORTHWESTERLY WINDS FOR WEDNESDAY AND
THURSDAY...BRINGING AN END TO THE POTENTIAL FOR HEAVY FREEZING
SPRAY.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
WIND CHILL ADVISORY FROM MIDNIGHT EST /11 PM CST/ TONIGHT TO 10
AM EST /9 AM CST/ MONDAY FOR MIZ011-084.
LAKE EFFECT SNOW ADVISORY UNTIL 7 AM EST MONDAY FOR MIZ085.
LAKE EFFECT SNOW ADVISORY UNTIL 7 PM EST /6 PM CST/ THIS EVENING
FOR MIZ001>003-005-009.
WIND CHILL ADVISORY UNTIL 10 AM EST /9 AM CST/ MONDAY FOR MIZ002-
009-010.
LAKE EFFECT SNOW ADVISORY UNTIL 1 PM EST MONDAY FOR MIZ006-007.
LAKE EFFECT SNOW WATCH FROM MONDAY EVENING THROUGH TUESDAY
EVENING FOR MIZ006-007.
WIND CHILL ADVISORY FROM 4 AM TO 10 AM EST MONDAY FOR MIZ004-005.
LAKE SUPERIOR...
HEAVY FREEZING SPRAY WARNING UNTIL 1 AM EST WEDNESDAY FOR LSZ267.
HEAVY FREEZING SPRAY WARNING UNTIL 7 AM EST WEDNESDAY FOR LSZ266.
HEAVY FREEZING SPRAY WARNING UNTIL 1 PM EST MONDAY FOR LSZ265.
HEAVY FREEZING SPRAY WARNING UNTIL 7 AM EST MONDAY FOR LSZ248-
249-264.
HEAVY FREEZING SPRAY WARNING UNTIL 1 AM EST MONDAY FOR LSZ263.
HEAVY FREEZING SPRAY WARNING UNTIL 7 PM EST /6 PM CST/ THIS
EVENING FOR LSZ162-240>247.
HEAVY FREEZING SPRAY WARNING UNTIL 6 PM EST MONDAY FOR LSZ250-
251.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...SRF
LONG TERM...JLB
AVIATION...SRF
MARINE...SRF
AREA FORECAST DISCUSSION
NWS GRAND FORKS ND
249 PM CST SUN DEC 29 2013
.SHORT TERM...(THIS EVENING THROUGH MONDAY NIGHT)
ISSUED AT 248 PM CST SUN DEC 29 2013
FORECAST CHALLENGE TONIGHT WILL BE EASTWARD EXTEND OF CLOUDS OVER
CENTRAL NORTH DAKOTA AND THEIR IMPACT ON TEMPS AND WIND CHILL
HEADLINES. OVERALL CLOUDS ADVECTING EAST QUICKER THAN INITIALLY
THOUGHT...AND MAY MAKE DEVILS LAKE BY 00Z. MODELS HAVE STRUGGLED
TO WITH PICKING UP ON THE MOISTURE...MAINLY HIGHLIGHTING THE
HIGHER CLOUDS OVER MINOT AND WEST. USING MAINLY SATELLITE TRENDS
FOR THE NEAR TERM AND MORE OF A ECMWF/NAM BLEND FOR THE EARLY PART
OF THE WEEK.
TONIGHT...CLOUDS WILL SLOWLY SPREAD INTO EASTERN ND AND APPROACH
THE RRV BY MIDNIGHT. A RATHER BULLISH CROSS SECTION FROM RUGBY TO
GRAND FORKS BRINGS CLOUDS INTO GFK BY 03Z..WHICH I THINK IS A BIT
TOO FAST. AS STATED PREVIOUSLY...MODELS ARE STRUGGLING WITH
ESPECIALLY THE LOWER CLOUDS THAT WERE PRESENT EARLY THIS MORNING.
THE RAP AVIATION FLIGHT RULES PRODUCT BRINGS THE LOW CLOUDS INTO
THE VALLEY AROUND THE 06Z/07Z TIME FRAME...BUT MID CLOUD SHOULD
ARRIVE PRIOR TO THAT. SO THE QUESTION BECOMES HOW FAST WILL TEMPS
DROP OFF AS THE SUN ANGLE DECREASES IN THE LATE AFTN...AND THEIR
IS ENOUGH WIND TO KEEP US IN ADVISORY CRITERIA THROUGH CURRENTLY
ADVERTISED TIMES. WILL NOT MAKE ANY CHANGES TO HEADLINES AT THIS
POINT BUT MAY SEE ADVISORY CANCELLED ACROSS EASTERN ND WELL AHEAD
OF SCHEDULE IF CLOUDS CAN LEVEL OFF THE TEMP CURVE QUICK ENOUGH.
OTHER ISSUE IS THAT WINDS ARE RATHER LIGHT...BUT ONLY TAKES 2 TO 3
KNOTS IN THE COLDEST AIR TO GET APPARENT TEMPS IN ADVISORY
CRITERIA. AGAIN...WILL KEEP HEADLINES IN PLACE AS IT IS GOING TO
BE DARN COLD TONIGHT WITHIN AND EAST OF THE VALLEY.
TOMORROW AND TOMORROW NIGHT...A WEAK WAVE WILL MOVE ACROSS CENTRAL
DAKOTAS AND SHOULD RESULT IN A BAND OF VERY DRY FLUFF ACROSS THE
CENTRAL PART OF THE STATE. THIS MAY CLIP THE SHEYENNE
VALLEY...WITH THE BEST CHANCES FOR UP TO TWO INCHES OF FLUFF BEING
FROM EDDY DOWN TO RANSOM/SARGENT COUNTIES. EXPECT SNOWFALL TO BE
INTO MAINLY WEST CENTRAL MN AFTER NOON...AND OUT OF THE REGION BY
EARLY MONDAY EVENING.
.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 248 PM CST SUN DEC 29 2013
TUESDAY AND WEDNESDAY...A SERIES OF WAVES EMBEDDED IN THE NW FLOW
PATTERN WILL BRING MORE CHANCES OF LIGHT SNOW MAINLY IN THE FAR
WEST ON TUE AND WED. THE WED SYSTEM...ALTHOUGH WEAKER AND
DRIER...SHOULD GIVE OUR CWA A LITTLE BETTER CHANCE AS THE UPPER
PATTERN SHIFTS EAST AND THE TRACK OF THE WAVES MOVES FROM THE
CENTRAL TO THE EASTERN DAKOTAS. EACH WAVE WILL GENERALLY BE MORE
DRY FLUFF THAT MAY ACCUMULATE AN INCH OR TWO DUE TO HIGH SNOWFALL
RATIOS WITH VERY LITTLE LIQUID EQUIVALENT.
WEDNESDAY NIGHT-SUNDAY...MODELS ARE IN GOOD AGREEMENT. THE PERIOD
STARTS WITH THE REGION IN NORTHWEST FLOW ALOFT...ALONG WITH HIGH
PRESSURE AND VERY COLD TEMPERATURES. THE UPPER PATTERN THEN
DEAMPLIFIES...ALLOWING ZONAL FLOW BY THE WEEKEND. THIS WILL LEAD TO
MUCH WARMER TEMPERATURES ON FRIDAY. A SYSTEM WILL MOVE THROUGH
SOUTHERN CANADA...SENDING A COLD FRONT THROUGH THE FA LATE FRIDAY OR
EARLY SATURDAY. LIGHT SNOW AND WINDY CONDITIONS POSSIBLE WITH THIS
FEATURE...ALTHOUGH DETAILS ARE FUZZY. TEMPERATURES WILL BE A BIT
COOLER FOR THE WEEKEND (COMPARED TO FRIDAY). MODELS SHOW A MUCH
STRONGER COLD FRONT POSSIBLE FOR LATER SUNDAY OR EARLY MONDAY.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY AFTERNOON)
ISSUED AT 105 PM CST SUN DEC 29 2013
HIGH PRESSURE WILL LEAD TO MOSTLY CLEAR SKIES THROUGH AT LEAST THE
FIRST HALF OF THIS PERIOD. A CLIPPER SYSTEM WILL BRING MID-LEVEL
CLOUDS INTO THE REGION FROM WEST TO EAST DURING THE SECOND HALF OF
THIS PERIOD...WITH -SN AND MVFR CONDITIONS LIKELY AFFECTING KDVL AND
KFAR MONDAY MORNING.
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...WIND CHILL ADVISORY UNTIL 9 PM CST THIS EVENING FOR NDZ038-049-
052.
WIND CHILL ADVISORY UNTIL 6 AM CST MONDAY FOR NDZ008-016-027-029-
030-039-053.
WIND CHILL ADVISORY UNTIL MIDNIGHT CST TONIGHT FOR NDZ006-007-
014-015-024-026-028-054.
MN...WIND CHILL ADVISORY UNTIL 6 AM CST MONDAY FOR MNZ001>009-013>017-
022>024-027>032-040.
&&
$$
SHORT TERM...SPEICHER
LONG TERM...TG/SPEICHER
AVIATION...TG
AREA FORECAST DISCUSSION
NWS BISMARCK ND
1128 AM CST SUN DEC 29 2013
.UPDATE...
ISSUED AT 1130 AM CST SUN DEC 29 2013
MAIN UPDATES WERE TO CANCEL ADDITIONAL PORTIONS OF WIND CHILL
ADVISORY AND TO REPLACE THE WIND CHILL WARNING ALONG OUR FAR
EASTERN COUNTIES WITH A WIND CHILL ADVISORY. ALSO ADJUSTED SKY
COVER TO ACCOUNT FOR SLOWLY EXPANDING CLOUD FIELD THAT IS SLOWLY
PUSHING EASTWARD. EASTERN EDGE OF CLOUDS RUNS APPROXIMATELY FROM
BOTTINEAU COUNTY SOUTHWARD THROUGH SHERIDAN...KIDDER...LOGAN AND
MCINTOSH COUNTIES. AREAS EAST OF THIS LINE CONTINUE TO SEE WIND
CHILLS VALUES FROM 25 BELOW TO 35 BELOW ZERO. OTHERWISE...FORECAST
REMAINS ON TRACK WITH NEXT QUICK MOVING CLIPPER THAT WILL SPREAD
SNOW FROM NORTHWEST TO SOUTHEAST LATE TODAY INTO MONDAY MORNING.
12Z NAM SEEMS A LITTLE FASTER THAN GFS AND 00Z ECMWF ALTHOUGH
AREAL COVERAGE IS SIMILAR AMONG ALL 3 MODELS AND THE SREF.
UPDATE ISSUED AT 900 AM CST SUN DEC 29 2013
CLOUDS ACROSS WESTERN ND HAVE REMAINED IN PLACE WITH TEMPERATURES
AROUND ZERO AND WIND CHILL VALUES ABOVE ADVISORY CRITERIA...SO
HAVE CANCELLED WIND CHILL ADVISORY FOR THIS AREA. WIND CHILLS
IMMEDIATELY EAST OF CLOUDS REMAIN IN ADVISORY/WARNING RANGE AND
HAVE CONTINUED THE HEADLINES THERE. OTHERWISE...FORECAST REMAINS
ON TRACK.
UPDATE ISSUED AT 639 AM CST SUN DEC 29 2013
MID LEVEL CLOUDS OVER WESTERN NORTH DAKOTA THIS MORNING MORE
EXPANSIVE THAN MODELS FORECAST AT 700MB....BUT MOISTURE AT H850 IN
MODELS...JUST NOT SHOWING UP AT THAT LEVEL. KEPT CLOUDS IN FORECAST
WEST INTO CENTRAL. ALTHOUGH WIND CHILLS JUST A BIT OUT OF CATEGORY
WEST ANY BUT OF WIND WILL LOWER INTO CATEGORY.
UPDATE
ISSUED AT 550 AM CST SUN DEC 29 2013
QUICK UPDATE TO ACCOUNT FOR LINGERING LARGE AREA OF BKN-OVC CIGS
ACROSS WESTERN NORTH DAKOTA. AS MENTIONED BELOW...MODELS ARE
POORLY DEPICTING THESE CLOUDS...WHICH GREATLY AFFECT THIS MORNINGS
TEMPERATURES FORECAST. THE LATEST RAP APPEARS TO HINT AT THESE
CLOUDS...WHICH HOLD TOGETHER WELL INTO THIS MORNING. THUS
INCREASED SKY COVER WEST AND WARMED TEMPERATURES NEAR TO
UNDERNEATH THE CLOUDS. STILL COLD WHERE SKIES HAVE GONE
CLEAR...AROUND 25 BELOW AND PERHAPS COLDER WITH DEWPOINTS NEARING
30 BELOW.
&&
.SHORT TERM...(THIS MORNING THROUGH TONIGHT)
ISSUED AT 411 AM CST SUN DEC 29 2013
FORECAST HIGHLIGHTS IN THE SHORT TERM PERIOD WILL BE VERY COLD
TEMPERATURES THIS MORNING AND AFTERNOON...FOLLOWED BY A SHOT OF
LIGHT ACCUMULATING SNOW FOR TONIGHT.
CURRENTLY...ARCTIC HIGH PRESSURE CONTINUES SOUTH INTO NORTH
DAKOTA EARLY THIS MORNING...RESULTING IN A RAPIDLY CLEARING SKY
ACROSS MY NORTH CENTRAL SPREADING SOUTHWARD. MODELS FAILED TO PICK
UP ON A RATHER LARGE AREA OF 4-5K FOOT AGL CIGS FROM FAR SOUTH
CENTRAL SASKATCHEWAN EXTENDING SOUTHEAST INTO NORTHWESTERN NORTH
DAKOTA. IT IS UNCLEAR IF THESE CLOUDS WILL CLEAR OUT AT ALL WITH
RETURN FLOW DEVELOPING AFTER 12Z THIS MORNING AND INCREASING
CLOUDS EXPECTED FROM THE WEST. BUFFER SOUNDINGS DO SHOW A GRADUAL
SCATTERING OUT AFTER SUNRISE AS THE TOP OF THE CLOUD LAYER
DE-SATURATES DOWNWARD...SO DID TREND SKY COVER FOR THIS AREA TO
SCATTERED/MOSTLY SUNNY 12-15Z THIS MORNING.
AS THE SKY CLEARS AND WINDS CONTINUE TO SUBSIDE UNDERNEATH THE
ARCTIC HIGH...TEMPERATURES WILL RAPIDLY PLUMMET. ALREADY NEAR 15
BELOW OVER MY FAR NORTH CENTRAL...AND EXPECT LOWS OF 20 BELOW TO
NEAR 25 BELOW ZERO ACROSS PORTIONS OF CENTRAL NORTH DAKOTA THROUGH
8-9AM SUNDAY. WARMER SOUTHWEST AROUND 5 BELOW WHERE LINGERING
CLOUDS ARE FORECAST. WIND CHILL HEADLINES LOOK FINE AND WILL MAKE
NO CHANGES WITH THIS FORECAST ISSUANCE.
COLD START OF THE DAY WILL RESULT IN SUBZERO HIGHS OVER MY CENTRAL
(NEAR -5F) AND MY EAST (NEAR -10F). BETTER SOUTHERLY RETURN FLOW
AND WAA ACROSS MY SOUTHWEST WHERE WE HAVE FORECAST HIGHS AROUND
10F ABOVE ZERO.
ACTIVE WEATHER PATTERN CONTINUES AS ANOTHER CLIPPER TRACKS
SOUTHEAST ACROSS THE NORTHERN PLAINS TONIGHT. UPPER LEVEL 125KT
JET STREAK NOW RIDING OVER THE UPPER LEVEL RIDGE PARKED OFF THE
WEST COAST WILL MOVE SOUTHEAST TONIGHT TO OVER THE NORTHERN HIGH
PLAINS OF MT/WY. THIS FEATURE WILL DRIVE A MID LEVEL IMPULSE AND
ASSOCIATED SURFACE LOW FROM EASTERN MONTANA THIS EVENING
SOUTHEAST INTO CENTRAL SOUTH DAKOTA AFTER MIDNIGHT. THE TRACK OF
THIS LOW AND PLACEMENT OF UPPER LEVEL DIVERGENCE WILL FAVOR
PRECIPITATION DEVELOPING ACROSS THE NORTHWEST THIS EVENING...THEN
SPREADING EAST-SOUTHEAST LATE SUNDAY NIGHT ACROSS CENTRAL ND AND
EVENTUALLY INTO THE JAMES RIVER BASIN AND SOUTHERN RED RIVER
VALLEY MONDAY MORNING. THANKS TO SNOW RATIOS RANGING FROM 15:1 TO
20:1...MAY SEE IN INCH TO AN INCH AND ONE HALF OF SNOW BY MONDAY
MORNING ALONG THE ABOVE MENTIONED TRACK...ROUGHLY ACROSS THE
NORTHWEST QUARTER OF THE STATE SOUTHEAST THROUGH MINOT AND
BISMARCK AND THROUGH THE JAMES RIVER BASIN.
WHILE WINDS WILL TRANSITION TO NORTH/NORTHWEST BEHIND THIS
CLIPPER AND INCREASE SOME...GRADIENT FORCING AND PRESSURE RISES
RATHER WEAK SO AM NOT ANTICIPATING MUCH BLOWING SNOW POTENTIAL AT
THIS TIME.
ONE MORE THING OF NOTE...EXPECT TEMPERATURES TO WARM THIS EVENING
ESPECIALLY SOUTHWEST INTO SOUTH CENTRAL WHERE THE BEST WAA WILL
OCCUR TONIGHT AHEAD OF THE LOW BEFORE CAA OVERTAKES US FOR MONDAY
DAYTIME. THUS EXPECT TO SEE TODAYS HIGH TEMPERATURES REACHED MANY
LOCATIONS SOMETIME THIS SUNDAY EVENING...AND MONDAYS HIGHS MOST
LIKELY SOMETIME AFTER MIDNIGHT THROUGH MONDAY MORNING.
.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 411 AM CST SUN DEC 29 2013
MODELS CONTINUE THE TREND OF A COLD UPPER LOW OVER CENTRAL CANADA
REMAINING QUASI STATIONARY...ALBEIT MEANDERING A BIT...DURING THE
EXTENDED FORECAST PERIOD. AT THE SAME TIME...EASTERN PACIFIC RIDGING
REMAINS IN PLACE FEEDING MILDER TEMPERATURES TO THE WESTERN US.
ACROSS THE NORTHERN PLAINS...THE BATTLE BETWEEN THE WARM AND COLD
WILL BRING AN ACTIVE WEATHER PATTERN TO THE REGION. TUESDAY AND
WEDNESDAY MORNINGS SHOULD REMAIN QUITE COLD...WITH LOWS AS COLD AS
THE MID 20S BELOW ACROSS THE NORTH CENTRAL. COLD WIND CHILLS WILL
AGAIN BE FEATURED AT THIS TIME ESPECIALLY ALONG THE CANADIAN BORDER.
THEN A SHORTWAVE WILL MOVE ACROSS THE NORTHERN PLAINS AND BRING A
CHANCE OF SNOW THROUGH THE FIRST HALF OF THE PERIOD. ACCUMULATING
SNOW APPEARS LIKELY TUESDAY AND WEDNESDAY. AFTER WEDNESDAY...THE
ARCTIC AIR GETS NUDGED BACK NORTH AND MODERATING TEMPERATURES...
ESPECIALLY BY FRIDAY AND SATURDAY MAKE THERE WAY BACK TO NORTH
DAKOTA.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z MONDAY MORNING)
ISSUED AT 639 AM CST SUN DEC 29 2013
BKN-OVC MID LEVEL CLOUDS WILL PERSIST THROUGH SUNDAY MORNING AND
WEST AND DRIFT SLOWLY EASTWARD INTO THE CENTRAL ASSOCIATED WITH
WEAK WARM ADVECTION IMPACTING KISN-KDIK-KMOT-KBIS. OVERALL...VFR
FLIGHT CONDITIONS EXPECTED THROUGH SUNDAY AFTERNOON. ANOTHER
CLIPPER STORM SYSTEM WILL MOVE SOUTHEAST INTO THE DAKOTAS SUNDAY
EVENING OVERNIGHT INTO MONDAY MORNING. EXPECT TO SEE DETERIORATING
FLIGHT CONDITIONS WEST SUNDAY EVENING IMPACTING KISN AND
KDIK...THEN EASTWARD LATER SUNDAY NIGHT IMPACTING KBIS-KMOT- KJMS.
CIGS ARE FORECAST TO DROP TO MVFR AND VIS IN FALLING SNOW FALLING
TO IFR AND POSSIBLY LOWER.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
WIND CHILL ADVISORY UNTIL 9 PM CST THIS EVENING FOR NDZ037-048-
051.
WIND CHILL ADVISORY UNTIL MIDNIGHT CST TONIGHT FOR NDZ005-013-
023-025.
&&
$$
UPDATE...JNS
SHORT TERM...NH
LONG TERM...WAA
AVIATION...WAA