Forecast Discussions mentioning any of
"HRRR" "RAP" "RR" "RUC13" "RUC" received at GSD on 02/23/15
AREA FORECAST DISCUSSION
NWS LITTLE ROCK AR
1126 PM CST FRI FEB 20 2015
.AVIATION...
MAINLY MVFR CEILINGS WITH PATCHY IFR CEILINGS WILL BE SEEN OVER
NORTHERN AND CENTRAL AREAS...WHILE VFR CEILINGS WITH PATCHY MVFR
CEILINGS OVER SOUTHERN AREAS WILL BE SEEN OVERNIGHT. AREAS OF RAIN
AND SHOWERS WILL BE SEEN OVER SOUTH AND CENTRAL AR...WHILE FREEZING
PRECIP OVER NORTH CENTRAL TO NORTHERN AR. OVERNIGHT...A SLOW WARMING
TREND WILL SPREAD OVER ALL OF AR...AND ANY FREEZING RAIN WILL CHANGE
OVER TO RAIN. WINDS WILL BE E TO SE AT 5 TO 15 MPH TONIGHT...THEN
GRADUALLY BECOME SE TO S TOWARD SATURDAY AM. LOW LEVEL WIND SHEAR
WILL BE PRESENT AS A SOUTH LOW LEVEL JET FORMS OVER AR. A COLD FRONT
WILL ALSO SLOWLY MOVE THROUGH AR ON SATURDAY AND BRING ISOLATED
THUNDER TO THE AREA.
&&
.PREV DISCUSSION... /ISSUED 616 PM CST FRI FEB 20 2015/
UPDATE...
WENT AND EXTENDED THE WINTER WEATHER ADVISORY THROUGH MIDNIGHT.
TEMPERATURES HAVE BEEN SLOW TO WARM THROUGH THE AFTERNOON AND
EVENING. 12Z WRF AND HRRR SEEM TO HAVE A DECENT JOB WITH
TEMPERATURE TRENDS THROUGH THE EVENING WITH MOST LOCATIONS ACROSS
NORTHERN ARKANSAS NOT WARMING UP TO FREEZING UNTIL CLOSE TO 6Z.
PREV DISCUSSION... /ISSUED 600 PM CST FRI FEB 20 2015/
AVIATION...
AREAS OF VFR AND MVFR CEILINGS WILL BE SEEN THIS EVENING AND
OVERNIGHT. MORE MVFR CEILINGS WITH PATCHY IFR CONDITIONS WILL
DEVELOP OVERNIGHT. AREAS OF RAIN AND SHOWERS WILL BE SEEN OVER SOUTH
AND CENTRAL AR...WHILE FREEZING PRECIP OVER NORTH CENTRAL TO
NORTHERN AR. THROUGH THE EVENING AND OVERNIGHT...WARM AIR WILL
GRADUALLY SPREAD INTO ALL OF AR...AND ANY FREEZING RAIN WILL CHANGE
OVER TO RAIN. WINDS WILL BE E TO SE AT 5 TO 15 MPH THIS EVENING AND
TONIGHT...BECOMING SE TO S TOWARD SATURDAY AM. LOW LEVEL WIND SHEAR
WILL DEVELOP TONIGHT AS A SOUTH LOW LEVEL JET FORMS AND MOVES INTO
AR. A COLD FRONT WILL ALSO SLOWLY MOVE THROUGH AR ON SATURDAY AND
BRING ISOLATED THUNDER TO THE AREA. (59)
PREV DISCUSSION... /ISSUED 240 PM CST FRI FEB 20 2015
SHORT TERM...TONIGHT THROUGH MONDAY NIGHT
SURFACE OBSERVATIONS SHOW WARM AIR MOVING IN TO SOUTHWEST ARKANSAS
AT THIS TIME. MOST AREAS IN THE CENTRAL AND SOUTHWEST ARE ABOVE
FREEZING...AND TEMPERATURES WILL CONTINUE TO RISE THROUGH THE
NIGHTTIME HOURS.
AS AN UPPER WAVE MOVES INTO ARKANSAS TONIGHT...AND APPROACHING LOW
PRESSURE PUSHES A WARM FRONT FURTHER INTO THE STATE...PRECIPITATION
WILL BECOME WIDESPREAD. WITH TEMPERATURES WARMING...ALL AREAS
SHOULD BE ABOVE FREEZING AFTER MIDNIGHT.
HAVE GONE AHEAD AND READJUSTED THE WINTER STORM WARNING TO EXPIRE AT
MIDNIGHT. WHILE MOST AREAS WILL NOT REACH WARNING CRITERIA...PREFER
TO LEAVE IT IN PLACE DUE TO ISSUES NOTED TODAY. WILL ALLOW THE
WINTER WEATHER ADVISORIES TO EXPIRE AT THEIR APPROPRIATE TIMES...
AS ANY ADDITIONAL WINTRY PRECIPITATION WILL BE INCONSEQUENTIAL.
THE AFOREMENTIONED LOW WILL DRAG A COLD FRONT ACROSS THE REGION ON
SATURDAY. WITH ELEVATED INSTABILITY PRESENT...THUNDERSTORMS WILL
BE POSSIBLE. TEMPERATURES WILL FALL BEHIND THE FRONT. ON SATURDAY
NIGHT...PRECIPITATION WILL SHIFT EAST OF THE REGION AS ARCTIC AIR
MOVES BACK IN.
ON SUNDAY...THE NORTH WILL STRUGGLE TO GET TO FREEZING...WHILE THE
CENTRAL AND SOUTH WILL STRUGGLE TO REACH THE 40S. ON SUNDAY NIGHT
THROUGH MONDAY NIGHT...SEVERAL UPPER WAVES WILL MOVE THROUGH THE
REGION. WITH ARCTIC AIR BACK IN PLACE...MOST PRECIPITATION THAT
FALLS WILL BE IN THE FORM OF SNOW...WITH THE EXCEPTION OF THE FAR
SOUTH...WHICH WOULD BE A MIX. WHILE IT DOESN/T LOOK HEAVY...IT MAY
BE ENOUGH TO LIGHTLY ACCUMULATE...PARTICULARLY OVER WESTERN AND
CENTRAL ARKANSAS. STAY TUNED.
LONG TERM...TUESDAY THROUGH FRIDAY
OVERALL THE MODELS ARE IN DECENT AGREEMENT ON HOW THE UPPER LEVEL
PATTERN WILL EVOLVE DURING THE FIRST HALF OF THE LONG TERM PERIOD.
BROAD UPPER TROUGHING WILL BE NOTED OVER THE EASTERN CONUS THROUGH
THE PERIOD...WITH THE REMNANTS OF A CLOSED UPPER LOW OVER CALIFORNIA
BEING ABSORBED INTO THE MEAN EASTERN TROUGH BY WED MORNING. BEYOND
THAT HOWEVER THE MODELS DIVERGE GREATLY...AND EVEN WITH THE TUE
NIGHT EARLY WED MORNING TIME FRAME THERE ARE SIGNIFICANT DIFFERENCES
IN THE HANDLING OF SHORTWAVE ENERGY AND THE ASSOCIATE PRECIP SHIELD.
THE GFS SHOWS LIGHT PRECIPITATION ACROSS MUCH OF THE FORECAST AREA
TUESDAY NIGHT AND EARLY WED MORNING WHICH...GIVEN THE TEMPERATURES
IN PLACE...WOULD BE OF THE WINTRY VARIETY. HOWEVER THE EUROPEAN IS
ALMOST COMPLETELY DRY. HAVE GONE SOMEWHAT HEAVY HANDED TOWARDS THE
EURO BUT WILL KEEP SOME SLIGHT CHANCE POPS IN THE SOUTHERN COUNTIES
TUE NIGHT AND WED TO ACCOUNT SOMEWHAT FOR WETTER GFS SOLUTION. WED
NIGHT ONWARD THOUGH...CONFIDENCE DROPS SIGNIFICANTLY. THE EURO
DEVELOPS A BROAD TROUGH ACROSS MUCH OF THE LOWER 48...WHILE THE GFS
IS NOTICEABLY DIFFERENT. THUS TIMING FOR ANY PARTICULAR DISTURBANCE
AND ASSOC PRECIPITATION IS DIFFICULT AT BEST. PREFER TO CARRY
NO MENTION OF PRECIP CHANCES DURING THAT PERIOD UNTIL SOMEWHAT OF A
CONSENSUS EMERGES.
ONE THING DOES SEEM WELL AGREED UPON AND THAT IS THAT TEMPERATURES
WILL REMAIN BELOW NORMAL...REGARDLESS OF WHICH MODEL YOU BELIEVE.
ANOTHER ARCTIC HIGH WILL SLIP SOUTH FROM CANADA TUE INTO WED...WITH
THE LEADING EDGE OF THE COLD AIR REACHING ARKANSAS BY THURSDAY.
AFTER HIGHS IN THE 40S TUE AND WED...AFTERNOON READINGS ON THURSDAY
WILL STRUGGLE TO BREAK THE FREEZING MARK IN THE NORTH AND
NORTHEAST...AND ONLY JUST MAKE 40 IN THE SOUTH.
&&
.PRELIMINARY POINT TEMPS/POPS...
BATESVILLE AR 30 44 29 34 / 100 100 20 20
CAMDEN AR 45 65 37 43 / 80 90 40 30
HARRISON AR 31 43 25 28 / 100 90 10 20
HOT SPRINGS AR 33 55 34 40 / 90 90 20 20
LITTLE ROCK AR 34 54 33 38 / 90 100 30 20
MONTICELLO AR 39 65 36 41 / 90 90 50 20
MOUNT IDA AR 34 53 34 40 / 90 90 20 20
MOUNTAIN HOME AR 28 44 25 30 / 100 90 20 20
NEWPORT AR 30 45 29 34 / 100 100 30 20
PINE BLUFF AR 36 61 34 39 / 90 100 40 20
RUSSELLVILLE AR 33 51 32 38 / 100 90 20 20
SEARCY AR 31 46 31 36 / 100 100 30 20
STUTTGART AR 34 55 33 37 / 90 100 40 20
&&
.LZK WATCHES/WARNINGS/ADVISORIES...
WINTER STORM WARNING UNTIL 6 AM CST SATURDAY FOR BAXTER-CLEBURNE-
FULTON-INDEPENDENCE-IZARD-JACKSON-SHARP-STONE.
WINTER WEATHER ADVISORY UNTIL 6 AM CST SATURDAY FOR BOONE-CONWAY-
FAULKNER-JOHNSON-MARION-NEWTON-POPE-SEARCY-VAN BUREN-WHITE-
WOODRUFF.
&&
$$
AVIATION...56
AREA FORECAST DISCUSSION
NWS PUEBLO CO
803 PM MST SUN FEB 22 2015
.UPDATE...
ISSUED AT 800 PM MST SUN FEB 22 2015
STEADY ACCUMULATING SNOW IS NOT LIKELY ACROSS THE FAR E PLAINS AND
PER COORD WITH SURROUNDING WFO/S...I REMOVED THE HILITES FOR THAT
REGION. /HODANISH
&&
.SHORT TERM...(THIS EVENING THROUGH MONDAY)
ISSUED AT 251 PM MST SUN FEB 22 2015
...HEAVY SNOW OVER THE MOUNTAINS CONTINUES...
...SNOW WINDING DOWN TONIGHT FOR THE LOWER ELEVATIONS...
IN GENERAL...FORECAST IS WORKING OUT FAIRLY WELL ACROSS THE CWA.
FORECAST AMOUNTS FOR THE NORTHERN AND EASTERN ZONES WERE TOO
HIGH...AND TOO LOW FOR THE MTS AND SRN ZONES...BUT OVERALL AMOUNTS
ARE NOT TOO SURPRISING. AS THE UPPER TROUGH SHEARS OFF TO THE WEST
OVER CA...AND MID LEVEL WINDS CONTINUE TO VEER TO THE SW AND
W...WILL SEE SNOWFALL GRADUALLY DIMINISH OVER THE ERN PLAINS E OF I-
25 TONIGHT...SO HAVE REDUCED POPS THROUGH TONIGHT IN THAT AREA. WILL
LEAVE A SNOW ADVISORY GOING WITH ADDITIONAL LIGHT ACCUMS OF AN INCH
OR TWO POSSIBLE...AND CONTINUED ICY ROAD CONDITIONS. HIGH RES MODELS
ARE SHOWING THE HEAVIER SNOW GRADUALLY BEING TIED TO THE ERN MTS AND
HIGHER TRRN...AND THIS LOOKS REASONABLE. THERE COULD BE SOME BANDED
PRECIP SPILLING OVER TO PORTIONS OF THE I-25 CORRIDOR...ESPECIALLY W
OF I-25...THROUGH THIS EVENING...SO WILL LEAVE THE WARNING INTACT
FOR THE I-25 ZONES. IN FACT...THE HRRR CONTINUES TO SHOW SN PICKING
UP FOR A BIT EARLY THIS EVENING OVER EL PASO COUNTY BEFORE
DIMINISHING AFTER MIDNIGHT. LATER SHIFT CAN REEVALUATE AND
DOWNGRADE THE WARNING IF IT LOOKS LIKE THIS WILL NOT MATERIALIZE.
OVER THE MTS...SNOW CONTINUES THROUGH TOMORROW. WIND SENSOR IS OUT
AT KCPW...BUT AS MENTIONED IN THE EARLIER UPDATE BLIZZARD CONDITIONS
WERE OCCURRING THERE AND WILL LIKELY CONTINUE THROUGH PERIODS OF
MONDAY BEFORE THINGS BEGIN TO QUIET DOWN. LATEST GUIDANCE SUGGESTS
AN ADDITIONAL 2-3 FEET OVER THE SAN JUANS BY TUESDAY...SO WOULD NOT
BE SURPRISED TO SEE A FEW SPOTS NEAR 4 FEET BY THE TIME THIS
ENDS...AND WITH HIGH WINDS SOME SERIOUS DRIFTING AS
WELL...INCREASING AN UNSTABLE SNOW LOAD ON THE SLOPES AND RESULTING
IN EXTREME AVALANCHE THREAT OVER THE HIGH COUNTRY FOR THE NEXT FEW
DAYS.
INTERESTINGLY...LATEST GUIDANCE IS SHOWING H7 TEMPS OF MINUS 21
DEGREES OVER OUR AREA TONIGHT...SIGNIFICANTLY COLDER THAN WHAT THE
MODELS WERE SHOWING JUST A COUPLE OF DAYS AGO...AND IN LINE WITH THE
ECMWF GUIDANCE FROM A WEEK AGO! THE MUCH COLDER AIR HAS CUT BACK A
BIT ON DENDRITIC SNOW GROWTH...AND LIMITED SNOW AMOUNTS TO SOME
EXTENT FOR OUR ERN ZONES. AS A RESULT OF THE COLDER AIR
ALOFT...EXPECT SOME LOWS CLOSE TO ZERO TONIGHT EVEN WITH THE CLOUD
COVER...AND HAVE REDUCED HIGHS A BIT FOR TOMORROW WITH TEMPS
PROBABLY STAYING IN THE TEENS FOR THE MOST PART.
EXPECT GRADUAL IMPROVEMENT TOMORROW FOR THE PLAINS...AS WRLY FLOW
INCREASES. MODELS ARE SHOWING A LACK OF QPF THERE TOMORROW...BUT
WITH ABUNDANT LOW LEVEL MOISTURE AND CONTINUED SHALLOW UPSLOPE...AM
RELUCTANT TO REMOVE POPS COMPLETELY...SO WILL LEAVE LOW POPS IN
PLACE OVER THE PLAINS. OVER THE MTS...HEAVY SNOW CONTINUES AT TIMES
WITH BLIZZARD CONDITIONS FOR THE ERN SAN JUANS. SAN LUIS VALLEY WILL
BE BETWEEN THE TWO REGIMES AND COULD SEE SOME SHSN...BUT NOTHING
PARTICULARLY HEAVY EXPECTED. WELCOME BACK TO WINTER! ROSE
.LONG TERM...(MONDAY NIGHT THROUGH SUNDAY)
ISSUED AT 251 PM MST SUN FEB 22 2015
MONDAY NIGHT THE UPR LOW IS FORECAST TO MOVE EASTWARD FROM SRN
NV...WITH THE GFS SHOWING THE LOW CENTER OVR NERN AZ BY 12Z TUE AND
THE NAM BEING A LITTLE FARTHER WEST. EITHER WAY...SNOW CONTINUES OVR
THE SWRN CO MTNS. HOWEVER WITH THE GFS BEING FARTHER EAST THAN THE
NAM...PCPN IS ALSO FORECAST TO BE OVR THE SAN LUIS VALLEY AND THE
ERN MTNS...WHILE THE NAM HAS DRY CONDITIONS EVERY BUT THE SW MTNS.
ON TUE THE UPR LOW IS EXPECTED TO CONTINUE AN EASTWARD
TRACK...MOVING ACRS NRN NM...BRINGING MAINLY SOME PCPN CHANCES TO
MAINLY THE FAR SOUTHERN PORTIONS OF THE FORECAST AREA. HIGH TEMPS ON
TUE WL BE A LITTLE WARMER...BUT STILL BELOW AVERAGE...ESPECIALLY
WITH THE SNOW COVER.
TUE NIGHT AND EARLY WED DRY CONDITIONS ARE EXPECTED OVR THE AREA AS
THE UPR LOW MOVES INTO NORTHERN TX. A NEW UPR TROF DROPS INTO THE
STATE FROM THE SOUTH BY LATE WED MORNING...PUSHING MORE COLD AIR
INTO THE AREA. IN THE LATE MORNING OR EARLY AFTERNOON HOURS...PCPN
IS EXPECTED TO SPREAD SOUTH ACRS THE AREA AS WELL...WITH PROBABLY
THE HARDEST HIT AREAS BEING THE EASTERN MTS AND IMMEDIATELY ADJACENT
PLAINS AND THE PALMER DIVIDE. THE GFS AND ECMWF ARE IN PRETTY GOOD
AGREEMENT...KEEPING PCPN ACRS MUCH OF THE SERN PLAINS AND MTNS THRU
THU NIGHT AND MUCH OF FRI AS ANOTHER UPR DISTURBANCE MOVES INTO THE
AREA FROM THE PACIFIC NW. THIS WL BRING THE POTENTIAL FOR SEVERAL
INCHES OF SNOW OVR THE MTNS. UPSLOPE FLOW OVR ERN AREAS WL HELP TO
BRING SEVERAL INCHES TO THE THE WET MTNS...SOUTHERN SANGRES AND THE
ADJACENT PLAINS...WITH MAYBE A COUPLE TO A FEW INCHES ALONG THE I-25
CORRIDOR...AND LIGHTER ACCUMULATIONS OVR THE FAR SERN PLAINS.
UNSETTLE WEATHER IS FORECAST TO CONTINUE NEXT WEEKEND AS ANOTHER
UPR TROF AFFECTS THE STATE...KEEPING THE WEATHER COOL AND BRINGING
PCPN CHANCES TO MUCH OF THE AREA AND THE POTENTIAL FOR SEVERAL
INCHES OF SNOW IN THE MTNS.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z MONDAY EVENING)
ISSUED AT 251 PM MST SUN FEB 22 2015
SN WILL GRADUALLY WIND DOWN THIS EVE FOR KPUB AND
KCOS...AS ACCUMULATING SNOW BECOMES TIED TO THE HIGHER TRRN ALONG
THE RAMPARTS...WETS...AND SANGRES. WILL STILL SEE SOME AREAS OF
LIGHT TO MDT SN MOVE OUT OVER THE I-25 CORRIDOR THIS EVE...SO THERE
WILL BE THE CONTINUED THREAT OF IFR CONDITIONS. PERSISTENT SE FLOW
SHOULD KEEP KCOS IN IFR TO LIFR CONDITIONS THROUGH MON
MORNING...WITH AREAS OF FZFG POSSIBLE IN THE MORNING DUE TO THE SNOW
PACK AND VERY COLD CONDITIONS. AT KALS...MVFR TO IFR ALSO POSSIBLE
IN PERIODS OF LIGHT SN THROUGH AT LEAST THE FIRST PART OF MONDAY.
NOT MUCH OF A BREAK BETWEEN STORMS AS ANOTHER WINTER SYSTEM LOOKS TO
IMPACT OUR AREA LATE WED INTO THU. ROSE
&&
.PUB WATCHES/WARNINGS/ADVISORIES...
WINTER STORM WARNING UNTIL 5 AM MST MONDAY FOR COZ058>063-
072>088.
WINTER WEATHER ADVISORY UNTIL 5 PM MST MONDAY FOR COZ069>071.
WINTER STORM WARNING UNTIL 5 PM MST MONDAY FOR COZ064>067.
BLIZZARD WARNING UNTIL 11 PM MST MONDAY FOR COZ068.
&&
$$
UPDATE...HODANISH
SHORT TERM...28/ROSE
LONG TERM...28
AVIATION...ROSE
AREA FORECAST DISCUSSION
NWS NEW YORK NY
426 PM EST SAT FEB 21 2015
.SYNOPSIS...
A LOW PRESSURE SYSTEM TRACKS DOWN THE SAINT LAWRENCE RIVER VALLEY
TONIGHT THROUGH SUNDAY NIGHT...WITH ITS COLD FRONT CROSSING THE
AREA THROUGH SUNDAY AFTERNOON. AN ARCTIC FRONT PASSES THROUGH
SUNDAY NIGHT WITH ARCTIC HIGH PRESSURE BUILDS IN ITS WAKE THROUGH
MONDAY NIGHT BEFORE SLIDING OFF THE MID ATLANTIC COAST ON
TUESDAY. A COLD FRONT WILL THEN APPROACH THE AREA TUESDAY NIGHT
AND PASS THROUGH WEDNESDAY AFTERNOON OR NIGHT...FOLLOWED BY HIGH
PRESSURE FOR THE REST OF THE WEEK.
&&
.NEAR TERM /THROUGH SUNDAY/...
PRIMARY LOW CONTINUES TO TRACK NW THROUGH THE EASTERN GREAT LAKES
AND ST LAWRENCE RIVER VALLEY THIS EVENING INTO TONIGHT...WITH A WARM
FRONT APPROACHING THE REGION LATER TONIGHT...WITH POTENTIAL WEAK
WAVE DEVELOPMENT ALONG IT. ITS TRAILING COLD FRONT PASSES THROUGH
SUNDAY AFTERNOON.
MODERATE TO HEAVY SNOW OVER NYC/NJ METRO...RAPIDLY SPREADING INTO
LI AND SOUTHERN CT THIS EVENING...WITH A STEADY PLUME OF MOISTURE
COMING UP ALL THE WAY DOWN INTO THE MID ATLANTIC. PERIODS OF
MODERATE TO HEAVY SNOW EXPECTED ACROSS THE COASTAL PLAIN INTO THIS
EVENING...WITH SNOWFALL RATES UP TO 1 INCH PER HOUR. LIGHT TO
MODERATE SNOW FOR AREAS FAR NW OF NYC METRO.
HIGH RES MODELS AND HRRR HAVE CONTINUED THE TREND OF SHIFTING
HEAVIEST QPF AXIS A BIT FARTHER SE...ACROSS THE COASTAL PLAIN...WITH
THIS SYSTEM. STILL EXPECTING 3/4 TO 1 INCH QPF ACROSS THE COASTAL
PLAIN...BUT COULD BE AS LOW AS 1/4 TO 1/2 INCH ACROSS AREAS WELL NW
OF NYC. MODELS HAVE ALSO TRENDED COLDER SINCE THE 00Z RUNS.
WINTER WEATHER ADVISORIES CONTINUE FOR THE ENTIRE AREA. BASED ON
UPSTREAM RADAR AND HIGH-RES DATA...AND ABOVE THINKING...HAVE
ADJUSTED SNOWFALL AMOUNTS UPWARD FOR THE NYC/NJ METRO AND COAST AND
STATUS-QUO FOR INTERIOR. A NARROW BAND OF 5 TO 7 INCHES OF
SNOW...MARGINAL WARNING...IS NOT OUT OF THE QUESTION ACROSS THE
COASTAL PLAIN (INCLUDING NYC AND LI)...BUT LOW CONFIDENCE AT THIS
POINT THAT IT WILL BE WIDESPREAD ENOUGH TO UPGRADE TO WARNING AND
WITH LOOMING CHANGEOVER. IN FACT...THE RAP AND HRRR...ARE SHOWING
POTENTIAL FOR A 1/2 INCH OF QPF AS ALL SNOW ACROSS NYC AND LI
BEFORE CHANGEOVER.
AS FOR SNOWFALL AMOUNTS...A GENERAL 3 TO 6 INCH SNOWFALL ACROSS
THE NYC METRO...LI AND SE CT BEFORE CHANGEOVER THIS EVENING...WITH
LOCALLY 6+ INCHES. ACROSS NE NJ...LOWER HUDSON VALLEY AND SW CT A
GENERAL 4 TO 7 INCHES IS STILL LIKELY...BUT IF DRYING TREND
CONTINUES...AREAS FARTHER NW OF NYC...COULD END UP ON THE LOWER
END OF THE RANGE.
THE FORECAST CHALLENGES TONIGHT CONTINUE TO BE HOW FAST DOES A
LOW LEVEL WARM NOSE FROM AROUND 875-975 HPA MOVE IN AND DEGREE OF
SHALLOW COLD AIR GETTING LOCKED IN AT THE SURFACE AS COASTAL
FRONT/WARM FRONT APPROACH TONIGHT. BEST ESTIMATE IS FROM S TO N
FROM 02Z TO 06Z WITH ENSUING CHANGEOVER TO LIQUID. AT THE
SURFACE...12Z NAM AND SBU/ALY WRF INDICATING A WEAK MESO- LOW
DEVELOPING ALONG THE WARM FRONT OVER OR JUST SOUTH OF LI...WHICH
WOULD KEEP THE WARM FRONT SOUTH OF AND PROMOTE TRAPPING OF SUB-
FREEZING SURFACE AIR DOWN INTO AT LEAST NORTHERN PORTIONS OF LI
AND NYC METRO AND POINTS N AND W TONIGHT.
BASED ON THIS TREND...HAVE FORECAST MORE FREEZING RAIN/ICE ACCUM
AND FURTHER SOUTH INTO THE COASTAL PLAIN. EXPECTATION IS A BAND OF
A TENTH...POSSIBLY 2 TENTHS...OF AN INCH OF ICE IN A CORRIDOR
RUNNING FROM NE NJ...NORTHERN PORTIONS OF NYC METRO/LI INTO SW CT.
PRECIP WILL BECOMING LIGHT LATE TONIGHT...BUT COULD HAVE TEMPS
LINGERING NEAR FREEZING TILL AROUND DAYBREAK HERE...FOR AT LEAST
LIGHT FREEZING RAIN. SO HAVE EXTENDED ADVISORY HERE UNTIL 8 AM.
ELSEWHERE...ONLY BRIEF MIXING EXPECTED AFTER MIDNIGHT ACROSS FAR
INTERIOR PORTIONS OF THE LOWER HUDSON VALLEY AND SW CT WITH UP TO A
FEW HUNDREDTHS OF AN INCH ICE. ALONG THE SOUTHERN PORTIONS OF NYC/LI
AND SE CT...SURFACE TEMPS SHOULD BE ABLE TO WARM ENOUGH LATE
THIS EVENING AND AFTER MIDNIGHT FOR A TRANSITION TO MAINLY RAIN.
KEEP IN MIND THOUGH...WITH COLD PREDECESSOR TEMPS...ROAD ICING MAY
BE POSSIBLE ALL THE WAY TO THE COAST FOR AT LEAST A COUPLE OF HOURS
AFTER CHANGEOVER TO RAIN FOR AT LEAST.
PRECIP BECOMES LIGHTER LATE TONIGHT...TAPERING OFF FROM W TO E EARLY
SUNDAY MORNING. OTHERWISE...DRYING CONDS ON SUNDAY WITH PARTIAL
CLEARING.
TEMPERATURES WILL REMAIN STEADY INTO EARLY THIS EVENING ACROSS THE
INTERIOR...AND SLOWLY FALLING ALONG THE COAST. TEMPS THEN GRADUALLY
RISING LATE THIS EVENING INTO OVERNIGHT...CONTINUING TO RISE INTO
THE MID TO UPPER 30S.
&&
.SHORT TERM /SUNDAY NIGHT/...
SHORTWAVE AXIS CROSSES SUNDAY NIGHT...WITH LOW PRESSURE LIFTING INTO
SE CANADA...AND ARCTIC FRONT PRESSING THROUGH THE REGION. DRYING LOW
LEVEL NW FLOW WILL HAVE TEMPS DROPPING INTO THE TEENS CITY/COAST AND
SINGLE DIGITS INTERIOR. WINDCHILLS DROPPING TO 0 TO 5 ALONG THE
COAST BY MONDAY MORNING...AND 0 TO 5 BELOW ACROSS THE INTERIOR.
&&
.LONG TERM /MONDAY THROUGH SATURDAY/...
HIGH PRESSURE BUILDS IN MONDAY AND MONDAY NIGHT WITH COLD ADVECTION
THROUGH AT LEAST MONDAY MORNING. TEMPERATURES PROBABLY STILL FALL
THROUGH THE MORNING HOURS BEFORE PERHAPS RECOVERING A DEGREE OR TWO.
HIGHS FOR THE DAY PROBABLY OCCUR DURING THE PRE-DAWN HOURS...AND
WITH 900MB TEMPS FALLING TO AROUND -20C...EXPECT DAYTIME TEMPS IN
THE TEENS. FOR MONDAY NIGHT...WENT BELOW GUIDANCE BY A COUPLE OF
DEGREES OUTSIDE OF THE CITY. LOWS IN THE SINGLE DIGITS FOR THE
CITY...AND MOSTLY 5 BELOW TO 5 ABOVE ELSEWHERE. RECORD LOWS FOR MOST
OF OUR OFFICIAL CLIMATE SITES SHOULD BE BROKEN. WIND CHILLS EXPECTED
IN THE SINGLE DIGITS BELOW ZERO...DUE PRIMARILY TO THE ACTUAL
TEMPERATURE AND NOT SO MUCH THE WIND.
DRY FOR TUESDAY...THEN WARM ADVECTION COULD CAUSE SOME LIGHT SNOW
TUESDAY NIGHT INTO WEDNESDAY MORNING WITH BETTER OVERALL CHANCES
OVER THE NORTHERN ZONES. A COLD FRONT THEN MOVES THROUGH WEDS
AFTERNOON INTO NIGHT. MOISTURE BY THIS TIME ISN`T MUCH...SO JUST A
SLIGHT CHANCE OF A SNOW SHOWER. AFTER HIGHS IN THE 20S ON
TUESDAY...HIGHS MOSTLY 30-35 ON WEDNESDAY. CAA FOLLOWS BEHIND THE
FRONT...LEAVING US WITH HIGHS ONLY IN THE 20S ONCE AGAIN ON
THURSDAY...BUT AT LEAST WITH DRY WEATHER. HIGH PRESSURE WILL BE
BUILDING IN THROUGH FRIDAY...SO CONTINUED DRY...BUT WITH HIGHS ONLY
IN THE 20S AGAIN.
FOR SATURDAY...HIGH PRESSURE SHIFTS OFFSHORE WITH MODELS SHOWING LOW
PRESSURE MOVING IN FROM THE SW. WILL GO WITH SLIGHT CHC/CHC POPS
FOCUSED MORE IN THE AFTERNOON AND NIGHT. PCPN TYPE WOULD START AS
SNOW...BUT MIXED PCPN COULD COULD OCCUR AT NIGHT.
&&
.AVIATION /21Z SATURDAY THROUGH THURSDAY/...
LOW PRES MOVING INTO THE TN VALLEY WILL LIFT NORTH INTO THE REGION
TONIGHT AND WILL PASS OVER THE TERMINALS LATE TONIGHT AND THROUGH
SUNDAY MORNING.
SNOW CONTINUES TO SPREAD EAST ACROSS THE TERMINALS THROUGH THIS
EVENING. IFR/LIFR CONDS IN MODERATE TO LOCALLY HEAVY SNOW THROUGH
ABOUT 02Z. KSWF SHOULD STAY ALL SNOW FOR THE DURATION OF THE
EVENT...BUT THERE WILL BE A TRANSITION TO FZRA STARTING ALONG THE
COAST AND LIFTING NORTHWARD DURING THE EVENING HOURS.
FZRA AT KJFK/KISP/KGON SHOULD ONLY LAST FOR A BRIEF PERIOD BEFORE
PRECIP CHANGES TO PLAIN RAIN AFTER MIDNIGHT...AND THEN TAPERS OFF...
POSSIBLY AS A RAIN/SNOW MIX...SUNDAY MORNING.
KLGA/KEWR/KTEB/KHPN/KBDR CAN EXPECT A PROLONGED PERIOD OF FZRASN
THROUGH THE OVERNIGHT HOURS...TAPERING OFF AS A WINTRY MIX SUNDAY
MORNING.
SOUTH WINDS MAY GUST TO AROUND 20 KT FROM TIME TO TIME THROUGH THIS
EVENING...BUT WINDS THEN DIMINISH LATER THIS EVENING. SOUTH WINDS
BECOME SW AT LESS THAN 10 KT TONIGHT...AND THEN BECOME LGT/VRB LATE
TONIGHT AS THE LOW PASSES OVER THE REGION. WINDS THEN BECOME WNW
SUNDAY MORNING AT LESS THAN 10 KT.
STRONG LLJ WILL ALSO PASS THROUGH THE REGION...RESULTING IN SW WINDS
40-50 KT AT 2000 FT DURING THE LATE AFTERNOON/EVENING HOURS.
RUNWAY SNOW ACCUM FCST:
KJFK/KISP/KGON: 1-3
KLGA/KEWR/KTEB/KBDR: 2-4
KHPN: 3-5
KSWF: 4-6
RUNWAY ICE ACCUM FCST:
KJFK/KISP/KGON: TRACE
KLGA/KEWR/KTEB/KHPN/KBDR: 0.10-0.20 INCH.
.OUTLOOK FOR 18Z SUNDAY THROUGH THURSDAY...
.SUNDAY AFTERNOON...IMPROVING CONDS. NW WINDS 10 KT OR LESS.
.SUNDAY NIGHT...MVFR POSSIBLE EARLY...THEN VFR. NW WINDS 10-15 KT.
.MONDAY...VFR. NW WINDS 15-20 KT WITH 20-30 KT GUSTS.
.MONDAY NIGHT-WEDNESDAY. SUB-VFR OR LOWER POSSIBLE IN SN. COASTAL
STORM POSSIBLE. CONFIDENCE LOW ON TIMING.
.THURSDAY...VFR LIKELY.
&&
.MARINE...
SCA WINDS CONTINUE ON THE OCEAN THROUGH AROUND 06Z BEFORE
SUBSIDING...WITH SEAS BUILDING TO 6 TO 10 FT. MARGINAL SCA GUSTS
ACROSS SOUTHERN AND EASTERN BAYS THROUGH THIS TIME AS WELL.
SUB SCA WINDS EXPECTED LATE TONIGHT THROUGH SUN...BUT SOUTHERLY
SCA SWELLS CONTINUE ON THE OCEAN.
SUNDAY NIGHT AND MON...SMALL CRAFT ADVISORY LEVELS POSSIBLE ALL
WATERS BY DAYBREAK IN WAKE OF ARCTIC FRONT...WITH CONTINUATION OF
5+ FT SEAS ON THE OCEAN.
WINDS AND SEAS WILL GRADUALLY DIMINISH MONDAY AND MONDAY
NIGHT...WITH ALL WATERS DROPPING BELOW SCA CONDS MONDAY NIGHT. HIGH
PRESSURE BUILDS TO THE SOUTH...SHIFTING WINDS FROM WNW TO SW ON
TUESDAY...GENERALLY BELOW 15 KT. WINDS INCREASE A LITTLE TUESDAY
NIGHT AS THE PRESSURE GRADIENT TIGHTENS DUE TO LOW PRESSURE MOVING
JUST NORTH OF THE GREAT LAKES. THIS WILL DRAG A COLD FRONT THROUGH
THE WATERS SOMETIME LATE WEDNESDAY OR WEDNESDAY NIGHT. SCA CONDS ARE
THEREFORE PROBABLE ON THE OCEAN WATERS TUES NIGHT THROUGH WEDS
NIGHT...AND MARGINALLY AT ADVISORY CONDS ON ALL OTHER WATERS DURING
THIS PERIOD. HIGH PRESSURE BUILDS BACK IN ON THURSDAY...BUT GUSTS
WILL BE CLOSE TO 25 KT ON THE OCEAN WATERS.
NOTE THAT WITH EXTREMELY LOW AIR TEMPERATURES...ICE WILL CONTINUE
TO DEVELOP ACROSS THE REGION AND CAN DISRUPT MARITIME TRAVEL.
&&
.HYDROLOGY...
EXPECTING A LIQUID EQUIVALENT OF 1/4 TO 1/2 INCH FAR NW OF
NYC...WITH 1/2 TO 1 INCH FOR THE REMAINDER OF THE REGION. HEAVIEST
ACROSS EASTERN LI AND SE CT. THERE IS THE POTENTIAL FOR PONDING
OF OVER EASTERN LONG ISLAND AND COASTAL NEW LONDON
COUNTY...ESPECIALLY IN AREAS WITH DRAINS CLOGGED BY SNOW TONIGHT.
NO SIGNIFICANT PCPN AMOUNTS EXPECTED THROUGH AT LEAST FRIDAY.
ICE WILL CONTINUE TO DEVELOP ON LOCAL AREA RIVERS AND STREAMS AS
TEMPS CONTINUE TO AVERAGE WELL BELOW NORMAL.
&&
.OKX WATCHES/WARNINGS/ADVISORIES...
CT...WINTER WEATHER ADVISORY UNTIL 1 AM EST SUNDAY FOR CTZ008-011-
012.
WINTER WEATHER ADVISORY UNTIL 8 AM EST SUNDAY FOR CTZ005>007-
009-010.
NY...WINTER WEATHER ADVISORY UNTIL 1 AM EST SUNDAY FOR NYZ075-
079>081-178-179.
WINTER WEATHER ADVISORY UNTIL 8 AM EST SUNDAY FOR NYZ067>074-
078-176-177.
NJ...WINTER WEATHER ADVISORY UNTIL 8 AM EST SUNDAY FOR NJZ002-004-
006-103>108.
MARINE...SMALL CRAFT ADVISORY UNTIL 6 AM EST MONDAY FOR ANZ350-353-355.
&&
$$
SYNOPSIS...JC/NV
NEAR TERM...NV
SHORT TERM...NV
LONG TERM...JC
AVIATION...MPS
MARINE...JC/NV
HYDROLOGY...JC/NV
AREA FORECAST DISCUSSION
NWS JACKSONVILLE FL
854 PM EST SUN FEB 22 2015
...GRADUAL INCREASE IN RAIN CHANCES THROUGH MONDAY...
...AREAS OF FOG FOR TONIGHT/EARLY MONDAY MORNING...
.UPDATE...NEARLY STATIONARY FRONT ACROSS NRN CENTRAL GA TO SERN AL
TO SRN LA THIS EVENING WILL GET A NUDGE E AND SE AS MEAN LAYER
TROUGH OVER THE ERN U.S. MOVES DOWNSTREAM. RADAR TRENDS SHOW SHOWER
ACTIVITY OVER SE AL AND CENTRAL GA LIGHT TO MODERATE AT TIMES WITH
SOME EVIDENCE OF SHIFTING ESEWD. MOISTURE ACROSS OUR AREA HAS RISEN
SINCE YESTERDAY WITH DEWPOINTS IN THE UPPER 50S TO AROUND 60. EXPECT
RAIN CHANCES TO INCREASE AS THE FRONT EDGES INTO OUR GA ZONES TO
NEAR THE ALTAMAHA RIVER BY 12Z MON. WILL USE SCT POPS IN THE 30-40
PERCENT RANGE FOR LOCATIONS N OF A JESUP TO DOUGLAS LINE WITH REST
OF SE GA AROUND 10-20 PERCENT AS BEST LIFT WILL BE LOCATED N OF THE
AREA. MAY INCREASE POPS A BIT MORE FOR LOCATIONS N OF ALMA BASED ON
RADAR TRENDS AND HRRR GUIDANCE. TEMPS ONLY TO FALL TO THE MID TO
UPPER 50S TONIGHT. OTHER ISSUE IS THE PROSPECTS FOR FOG. WITH CLOUDS
INCREASING OVER SE GA PATCHY FOG STILL LOOKS GOOD THERE WITH AREAS
OF FOG WITH LOW CLOUDS FOR NE FL...DUE TO COMBINATION OF RADIATION
FOG AND ADVECTIVE FOG/LOW CLOUDS EMANATING FROM THE NE GULF OF
MEXICO. SOME DENSE FOG IS CERTAINLY POSSIBLE OVER NE FL AND POSSIBLY
EXTREME SE GA ZONES. MONDAY...COLD FRONT WILL MOVE THROUGH SE GA IN
THE MORNING AND NE FL DURING THE AFTN. THE FRONT WILL BRING A
GENERAL INCREASE IN RAIN CHANCES...MAINLY IN SE GA. COOLER HIGH
TEMPS EXPECTED...BUT STILL IN THE MID 60S N ZONES TO MID 70S S
PORTIONS.
&&
.AVIATION...MOISTURE WILL CONTINUE TO INCREASE TONIGHT AS A COLD
FRONT CONTINUES TO EDGE CLOSER TO THE AREA. THIS WILL LEAD TO AREAS
OF LATE NIGHT AND MORNING LOW CLOUDS AND FOG. HAVE PREVAILING MVFR
AT GNV AND VQQ BEGINNING AT 09Z WITH OCNL IFR BETEEN 09Z-13Z. FOR
THE REST OF THE TERMINALS HAVE OCNL MVFR BETEEN 10Z-14Z. PREVAILING
MVFR IS EXPECTED AT ALL TERMINALS BETWEEN 14Z-20Z BEFORE CIGS
IMPROVE INTO THE VFR CATEGORY. THE COLD FRONT WILL PUSH SE INTO THE
AREA MONDAY AFTERNOON. BEST CHANCE OF RAIN ACROSS SE GA WHERE SSI
WILL HAVE VCSH.
&&
.MARINE...CURRENT FORECAST ON TRACK. S TO SW WINDS AROUND 10-15 KT
AND SEAS 2 TO 4 FEET...AROUND 3 TO 5 FEET OFFSHORE. WIND AND SEA
CONDITIONS DETERIORATE ON MONDAY AS THE COLD FRONT MOVES INTO THE
FORECAST REGION. WITH ELEVATED DEWPOINTS IN THE MID TO UPPER 50S
SOME PATCHY SEA FOG IS POSSIBLE OVER SE GA NEARSHORE WATERS MONDAY
MORNING.
RIP CURRENTS: LOW RISK THROUGH MONDAY DUE TO LOW SEAS AND SURF.
&&
.PRELIMINARY POINT TEMPS/POPS...
AMG 56 65 42 52 / 30 30 40 40
SSI 56 63 46 50 / 20 40 40 50
JAX 57 71 48 53 / 10 40 50 50
SGJ 57 70 53 55 / 10 30 40 50
GNV 57 75 51 60 / 10 30 30 40
OCF 58 76 54 65 / 10 20 20 40
&&
.JAX WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
GA...NONE.
AM...SMALL CRAFT ADVISORY FROM 6 PM MONDAY TO MIDNIGHT EST TUESDAY
NIGHT FOR WATERS FROM ALTAMAHA SOUND GA TO FERNANDINA BEACH
FL FROM 20 TO 60 NM-WATERS FROM FERNANDINA BEACH TO ST.
AUGUSTINE FL FROM 20 TO 60 NM-WATERS FROM ST. AUGUSTINE TO
FLAGLER BEACH FL FROM 20 TO 60 NM.
SMALL CRAFT ADVISORY FROM 6 PM MONDAY TO 10 AM EST TUESDAY FOR
COASTAL WATERS FROM ALTAMAHA SOUND TO FERNANDINA BEACH FL
OUT 20 NM-COASTAL WATERS FROM FERNANDINA BEACH TO ST.
AUGUSTINE FL OUT 20 NM-COASTAL WATERS FROM ST. AUGUSTINE TO
FLAGLER BEACH FL OUT 20 NM.
&&
$$
SHASHY/PETERSON/WALKER
Area Forecast Discussion
NATIONAL WEATHER SERVICE LINCOLN IL
900 PM CST Sun Feb 22 2015
.UPDATE...
ISSUED AT 857 PM CST SUN FEB 22 2015
Strong Arctic high pressure will continue to build into the area
overnight on schedule. Surface temperatures are still above zero,
but wind speeds have been sufficient to drop Wind Chill values
below zero across most of the forecast area. While wind speeds
will die off some overnight as the high approaches and pressure
gradient relaxes, sub-zero air temperatures will allow Wind Chill
values to fall to advisory levels.
Going forecast is in good shape. Only a few tweaks for the latest
hourly trends are required.
&&
.SHORT TERM...(Tonight)
ISSUED AT 240 PM CST SUN FEB 22 2015
Another Arctic air mass settling into our area for tonight and
Monday bringing bitterly cold wind chills tonight through the
mid-morning hours of Monday with values in the -15 to -25 degree
range. Latest upstream observations mostly in the single digits
across north central through northeast Iowa with wind gusts up
to 30 mph at times. Early morning lows are expected to dip to
-2 in the far south to as low as -8 across the north just before
dawn Monday. The center of the Arctic high is forecast by models
to drift into southeast Iowa by 12z Monday with the surface ridge
axis extending northeast into northern Illinois. Forecast soundings
and the latest HRRR model suggests the cloud cover we have over the
area this afternoon will drift east and south later this evening
with mainly some cirrus for the first half of the night and then
a mostly clear sky is expected after midnight most areas. Current
Wind Chill Advisory will remain in place for late tonight through
9AM Monday morning.
&&
.LONG TERM...(Monday through Sunday)
ISSUED AT 240 PM CST SUN FEB 22 2015
As the center of the cold air mass drifts across the area tomorrow,
look for winds to diminish during the day but temperatures will be
slow to rise with afternoon highs struggling to 10 to 15. The high
should be moving off to our east by afternoon and early evening
with our next surface low and cold front tracking across southern
Canada southwest through the Northern Plains. Early in the evening,
surface winds will be light enough for our usual tank with early
evening temperatures before we see a steady or slowly rising trend
across the north and west, while further east with a lighter wind
flow, early morning lows will dip several degrees below zero Monday
night into Tuesday morning. As the deep surface low tracks north
of Lake Superior on Tuesday, a gusty south to southwest wind should
help the mercury climb into the mid 20s far east to the low to mid
30s far west where we should be able to mix out fairly well during the
afternoon. With the better upper forcing remaining well to our north
and very limited moisture, models not showing much if any precip
associated with the boundary as it swings across our area late in
the day, except for the GFS which continues to produce a large area
of 0.01 qpf with this system. Not worth much more than a chance for
flurries and will continue with that for later in the day on Tuesday.
Then we will see another cold air mass build gradually southeast thru
midweek.
The GFS and latest ECMWF continue to show a weak shortwave racing
southeast into the Plains on Wednesday along the periphery of the
next batch of cold air for the remainder of the work week. The
GFS keeps any precip associated with this wave to our west and
south while the latest ECMWF has trended in that direction as well
but does bring in some light QPF late Wednesday/Wednesday evening.
Based on the latest westward shift with the ECMWF, will only have
slight chances Wednesday night for light snow. Colder temperatures
filter into the area again Wednesday night with early morning lows
dropping into the single digits with wind chills dropping to near
-10 by Thursday morning.
And a real surprise here, the well below normal temperatures are
expected to hold on across our area through at least the end of
the work week with daytime highs in the teens and early morning
lows dropping into the single digits with a few below zero readings
again possible early Friday morning. Both the GFS and ECMWF indicate
a significant change to the upper pattern with more of a southwesterly
flow developing over the weekend which will lead to an increasing
threat for precipitation. Models showing more agreement from what
we saw yesterday with snow chances moving in starting on Saturday
night with the threat for snow or rain on Sunday with warming
temperatures. Even seeing some better agreement with the ensemble
members with respect to the pattern change along with timing of
the precip into our area later Saturday through Sunday. Temperatures
will start to turn around on Saturday and Sunday, but still average
below the normal highs of 40 to 45 across the area for late February.
&&
.AVIATION...(For the 00Z TAFS through 00Z Monday evening)
ISSUED AT 531 PM CST SUN FEB 22 2015
VFR aviation weather Condtions are expected to prevail across the
central Illinois terminals through the 00Z TAF valid time.
Mid/high level CIGS will gradually diminish with time, with mostly
clear skies expected by midday Monday. Northerly breezes from
10-15 kts tonight will become light/variable by Monday afternoon
as high pressure builds across the area.
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
WIND CHILL ADVISORY from Midnight tonight to 9 AM CST Monday FOR
ILZ027>031-036>038-040>057-061>063-066>068-071>073.
&&
$$
UPDATE...Bak
SHORT TERM...Smith
LONG TERM...Smith
AVIATION...Bak
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
758 PM CST SUN FEB 22 2015
.UPDATE...
757 PM CST
MADE A COUPLE TWEAKS TO GOING FORECAST`S TEMPERATURES...MAINLY TO
RAISE LOW TEMPS A BIT TONIGHT...ESPECIALLY IN THE URBAN HEAT
ISLAND AND ALSO NUDGED HIGHS UP A BIT MONDAY AS WELL. COLD ARCTIC
AIR CONTINUES TO SLOWLY FILTER INTO THE AREA...BUT GRADIENT IS
REMAINING TIGHT ENOUGH TO KEEP A BIT OF WIND BLOWING WHICH IS
PREVENTING TEMPS FROM TANKING DESPITE THE CLEAR SKY. THE TYPICALLY
COLDER AND MORE SHELTERED AREAS LIKE FOX AND ROCK RIVER VALLEYS
WILL LIKELY SEE WINDS DECOUPLE A BIT MORE THAN OTHER AREAS WITH
TEMPS DROPPING TO AROUND 10 BELOW THERE...BUT DOWNTOWN CHICAGO
WILL PROBABLY ONLY DROP TO AROUND ZERO. THE MINOR ADJUSTMENTS TO
TEMPERATURES AND WINDS SUGGEST THAT MOST AREAS WILL FALL SHORT OF
REACHING WIND CHILL ADVISORY CRITERIA...WITH MOST LIKELY AREAS TO
REACH IT BEING NORTH CENTRAL ILLINOIS INTO THE FAR WESTERN
CHICAGO SUBURBS...WITH WIND CHILLS ELSEWHERE LIKELY "ONLY"
DROPPING TO 15-20 BELOW. ITS POSSIBLE THAT MIDNIGHT SHIFT COULD
KILL WIND CHILL ADVISORY EARLY...BUT JUST NOT COMFORTABLE MAKING
CHANGES TO THE HEADLINE AT THIS TIME.
IZZI
&&
.SHORT TERM...
234 PM CST
TONIGHT THROUGH WEDNESDAY...
COLD TEMPERATURES AND DANGEROUSLY LOW WIND CHILLS TONIGHT AND EARLY
MONDAY ARE THE IMMEDIATE FORECAST CONCERNS IN THE SHORT TERM. WIND
CHILL ADVISORY REMAINS IN EFFECT FOR ENTIRE CWA FROM MIDNIGHT
TONIGHT THROUGH 10 AM CST MONDAY MORNING. COULD EVEN APPROACH
ROCKFORDS RECORD LOW OF -12 F.
1047 MB HIGH PRESSURE CENTERED OVER THE NORTHERN PLAINS THIS
AFTERNOON WILL CONTINUE TO SPREAD SOUTHEAST TO THE MID-MISSISSIPPI
VALLEY TONIGHT. ARCTIC AIR...VERY DRY AIR MASS AND CLEAR SKIES...
AND SLOWLY DIMINISHING WINDS WILL COMBINE TO PRODUCE BITTER COLD
SUB-ZERO TEMPERATURES ACROSS THE FORECAST AREA OVERNIGHT. WITH LOW
TEMPS REACHING FROM -2 TO -14 ACROSS THE CWA AND WINDS JUST UNDER 10
MPH BY MORNING...WIND CHILLS RANGING FROM NEAR 20 BELOW TO NEARLY 30
BELOW ARE EXPECTED BY SUNRISE MONDAY. THUS WIND CHILL ADVISORY
REMAINS IN EFFECT FOR ALL COUNTIES WITH NO CHANGES.
ON MONDAY...THE SURFACE HIGH AND EASTERN PORTION OF THE RIDGE AXIS
WILL CONTINUE TO PUSH SOUTHEAST ACROSS THE AREA IN THE MORNING
BEFORE BECOMING ELONGATED ACROSS THE OHIO VALLEY LATE IN THE DAY.
COLD MORNING MINS AND SHALLOW MIXING IN THE VICINITY OF THE RIDGE
WILL LIKELY KEEP DAYTIME TEMPS IN THE SINGLE DIGITS TO NEAR 10
DEGREES IN MOST AREAS...DESPITE WINDS BECOMING WEST-SOUTHWEST AND
STARTING TO INCREASE DURING THE AFTERNOON. THIS WILL LIKELY RESULT
IN A RECORD LOW-MAX TEMP FOR THE ROCKFORD AREA MONDAY...AS THE
CURRENT RECORD LOW-MAX FOR RFD 2/23 IS A FAIRLY MILD 17 DEGREES.
WIND CHILLS WILL REMAIN SUB-ZERO THROUGH THE DAY...DESPITE MOSTLY
SUNNY SKIES.
ATTENTION THEN TURNS TO ANOTHER STRONG SHORT WAVE TROUGH DIGGING
FROM MANITOBA INTO ONTARIO AND ACROSS THE NORTHERN LAKES INTO
TUESDAY...WHICH RESULTS IN DEEP SURFACE LOW PRESSURE PASSING
NORTHEAST OF THE GREAT LAKES MONDAY NIGHT AND TUESDAY AND TIGHTENING
OF THE SURFACE PRESSURE GRADIENT ACROSS THE MIDWEST. WEST-SOUTHWEST
WINDS WILL BECOME BLUSTERY MONDAY NIGHT SUPPORTING STEADY OR SLOWLY
RISING TEMPERATURES MONDAY NIGHT ESPECIALLY ACROSS THE NORTH WHERE
WINDS WILL BE STRONGEST. TEMPERATURES WILL RISE INTO THE 25-30
DEGREE RANGE DURING THE DAY TUESDAY BEFORE THE COLD FRONT TRAILING
THE CANADIAN LOW MOVES THROUGH LATE IN THE DAY...THOUGH THE GUSTY
SOUTHWEST WINDS TO 35 MPH AT TIMES WILL MAINTAIN A RAW FEEL TO THE
DAY WITH WIND CHILLS IN THE TEENS AT BEST (ABOVE ZERO AT LEAST).
CLOUDS WILL INCREASE TUESDAY MORNING AHEAD OF THE APPROACHING FRONT
WITH SCATTERED SNOW SHOWERS OR FLURRIES AT TIMES DURING THE DAY. THE
COLD FRONT MOVES THROUGH BY EARLY TUESDAY EVENING...WITH BLUSTERY
NORTHWEST WINDS BRINGING COLDER AIR BACK INTO THE REGION AT LEAST IN
A GLANCING NATURE INTO WEDNESDAY WITH SINGLE DIGIT TEMPS TUESDAY
NIGHT AND HIGHS IN THE TEENS AND WIND CHILLS IN THE POSITIVE SINGLE
DIGITS WEDNESDAY. A WEAK CLIPPER SYSTEM IS CURRENTLY PROGGED TO MOVE
JUST WEST OF THE AREA LATE WEDNESDAY AND WEDNESDAY NIGHT...WHICH MAY
BRING SOME LIGHT SNOW TO WESTERN PARTS OF THE CWA. LOW LEVEL WINDS
ALSO LOOK TO VEER MORE NORTH-NORTHEAST WHICH MAY BRING SOME LIGHT
SNOW SHOWERS INTO NORTHWEST INDIANA AND EVEN PARTS OF NORTHEAST
ILLINOIS. NOT TOO EXCITED ABOUT ACCUMULATIONS WITH LAKE EFFECT AT
THIS TIME...AS INVERSION HEIGHTS REMAIN FAIRLY LOW.
RATZER
&&
.LONG TERM...
234 PM CST
THURSDAY THROUGH SUNDAY...
REINFORCEMENT OF ARCTIC AIR CONTINUES THURSDAY AND THURSDAY NIGHT AS
ANOTHER SHORT WAVE TROUGH DIGS SOUTHEAST AND MAINTAINS DEEP LARGE
SCALE TROUGH OVER THE EASTERN CONUS. SURFACE HIGH BUILDS SOUTHEAST
FROM THE NORTHERN PLAINS THURSDAY...INTO DOWNSTATE ILLINOIS BY
FRIDAY MORNING. 850 HPA TEMPS DROP INTO THE -16 TO -20 C RANGE
DURING THE PERIOD WITH LIGHT WINDS OF THE SURFACE RIDGE AND CLEARING
SKIES AGAIN EXPECTED TO PRODUCE SUB-ZERO TEMPERATURES BY SUNRISE
FRIDAY MORNING AND HIGHS ONLY IN THE TEENS FRIDAY...WHICH FOR THE
END OF FEBRUARY IS A GOOD 20-25 DEGREES BELOW OUR NORMAL HIGHS WHICH
WOULD BE NEAR 40 FOR THE END OF THE MONTH.
LONGER RANGE MODEL SOLUTIONS DO OFFER SOME HOPE FOR A LITTLE
MODERATION IN TEMPERATURES NEXT WEEKEND...WITH A TROUGH ELONGATING
AND BECOMING CUT-OFF IN THE SOUTHWEST CONUS AND A BROAD UPPER RIDGE
DEVELOPING ACROSS THE SOUTHEASTERN CONUS SATURDAY AND SUNDAY. THUS
OUR ARCTIC HIGH EVENTUALLY MOVES OFF THE ATLANTIC COAST WITH
SOUTHERLY FLOW DEVELOPING ACROSS THE LOWER AND MIDDLE MISSISSIPPI
VALLEY BY SUNDAY. OF COURSE THIS HELPS TO FEED MILDER AND MORE HUMID
AIR NORTHWARD...FOR A NORTHERN STREAM UPPER TROUGH AND SURFACE LOW
WHICH WOULD ALSO BRING PRECIPITATION TO THE AREA SATURDAY NIGHT AND
SUNDAY. AT THIS DISTANCE HAVE MAINTAINED A CONSERVATIVE APPROACH
WITH TEMPS INTO THE MID-30S SUNDAY AND POTENTIAL FOR SOME SNOW...
THOUGH IF THESE MODEL TRENDS PERSIST IT COULD BE MILDER WITH MIXED
PRECIP OR RAIN ESPECIALLY ACROSS OUR SOUTHEAST.
RATZER
&&
.CLIMATE...
RECORD COLD TEMPERATURES ARE POSSIBLE IN ROCKFORD ON MONDAY
FEBRUARY 23RD.
RECORD LOW FOR 2/23: -12 IN 1910.
RECORD LOW MAX FOR 2/23: 17 IN 1934.
RC
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 03Z...
* NONE
IZZI
//DISCUSSION...UPDATED 00Z...
VFR CONDITIONS WITH NO SIGNIFICANT WINDS THROUGH TAF CYCLE.
IZZI
//ORD AND MDW CONFIDENCE...UPDATED 03Z...
* HIGH CONFIDENCE IN ALL FORECAST ELEMENTS
IZZI
//OUTLOOK FOR ORD/MDW FOR 12Z TUESDAY-12Z SUNDAY...UPDATED 00Z...
TUESDAY...STRONG/GUSTY SW WINDS. MVFR CIGS POSSIBLE LATE.
WEDNESDAY THROUGH SATURDAY...PRIMARILY VFR.
IZZI
&&
.MARINE...
332 PM CST
HIGH PRESSURE MOVING ACROSS THE NORTHERN PLAINS AND UPPER MIDWEST
THIS AFTERNOON INTO THE EVENING IS ALLOWING FOR NORTHERLY WINDS OF
15 TO 25 KT TO CONTINUE THIS AFTERNOON...WITH THESE SPEEDS TO
LIKELY CONTINUE FOR MUCH OF TONIGHT. THIS HIGH WILL DRIFT
SOUTHEAST THROUGH THE UPPER MIDWEST AND MID MISSISSIPPI VALLEY
TONIGHT THROUGH MONDAY AND THEN REACH THE MID ATLANTIC WEST TO THE
SOUTHERN PLAINS BY EARLY TUESDAY MORNING. AS THIS OCCURS...WINDS
WILL TURN WEST AND THEN SOUTHWEST SLIGHTLY DIMINISHING ON MONDAY
MORNING...BUT THEN INCREASE ONCE AGAIN MONDAY AFTERNOON WITH TO 30
KT WINDS LIKELY LATE IN THE AFTERNOON. WINDS WILL REALLY INCREASE
MONDAY NIGHT INTO TUESDAY OUT AHEAD OF SOUTHWARD MOVING LOW
PRESSURE OVER ONTARIO...WITH GALES LIKELY. HAVE ISSUED A GALE AND
FREEZING SPRAY WARNING OVER THE ENTIRE LAKE MONDAY NIGHT THROUGH
TUESDAY NIGHT AND HAVE NOT ISSUED A GALE WARNING FOR THE NEARSHORE
AT THIS TIME. HOWEVER...THEY DO APPEAR TO BE A POSSIBILITY VERY
EARLY TUESDAY MORNING AND WILL NEED TO CONTINUE MONITORING THIS
PERIOD FOR POSSIBLE PREVAILING GALES...AND EVEN FOR A LONGER
DURATION. DO HAVE HIGH CONFIDENCE WITH THE START TIME OF THE GALES
ACROSS THE LAKE BUT HAVE LOWER CONFIDENCE WITH THE END TIME...WITH
THE GALES POSSIBLY LASTING LONGER INTO TUESDAY NIGHT.
RODRIGUEZ
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...WIND CHILL ADVISORY...ILZ003-ILZ004-ILZ005-ILZ006-ILZ008-ILZ010-
ILZ011-ILZ012-ILZ013-ILZ014-ILZ019-ILZ020-ILZ021-ILZ022-
ILZ023-ILZ032-ILZ033-ILZ039...MIDNIGHT MONDAY TO 9 AM
MONDAY.
IN...WIND CHILL ADVISORY...INZ001-INZ002-INZ010-INZ011-
INZ019...MIDNIGHT MONDAY TO 9 AM MONDAY.
LM...GALE WARNING...LMZ080-LMZ669-LMZ671-LMZ673-LMZ675-LMZ777-LMZ779-
LMZ870-LMZ872-LMZ874-LMZ876-LMZ878...9 PM MONDAY TO 3 AM
WEDNESDAY.
HEAVY FREEZING SPRAY WARNING...LMZ080-LMZ669-LMZ671-LMZ673-
LMZ675-LMZ777-LMZ779-LMZ870-LMZ872-LMZ874-LMZ876-LMZ878...9
PM MONDAY TO 3 AM WEDNESDAY.
GALE WARNING...LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-LMZ565-LMZ567-
LMZ868...6 PM MONDAY TO 3 AM WEDNESDAY.
HEAVY FREEZING SPRAY WARNING...LMZ261-LMZ362-LMZ364-LMZ366-
LMZ563-LMZ565-LMZ567-LMZ868...6 PM MONDAY TO 3 AM WEDNESDAY.
SMALL CRAFT ADVISORY...INDIANA NEARSHORE WATERS UNTIL 10 PM SUNDAY.
&&
$$
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Area Forecast Discussion
NATIONAL WEATHER SERVICE LINCOLN IL
535 PM CST Sun Feb 22 2015
.SHORT TERM...(Tonight)
ISSUED AT 240 PM CST SUN FEB 22 2015
Another Arctic air mass settling into our area for tonight and
Monday bringing bitterly cold wind chills tonight through the
mid-morning hours of Monday with values in the -15 to -25 degree
range. Latest upstream observations mostly in the single digits
across north central through northeast Iowa with wind gusts up
to 30 mph at times. Early morning lows are expected to dip to
-2 in the far south to as low as -8 across the north just before
dawn Monday. The center of the Arctic high is forecast by models
to drift into southeast Iowa by 12z Monday with the surface ridge
axis extending northeast into northern Illinois. Forecast soundings
and the latest HRRR model suggests the cloud cover we have over the
area this afternoon will drift east and south later this evening
with mainly some cirrus for the first half of the night and then
a mostly clear sky is expected after midnight most areas. Current
Wind Chill Advisory will remain in place for late tonight through
9AM Monday morning.
&&
.LONG TERM...(Monday through Sunday)
ISSUED AT 240 PM CST SUN FEB 22 2015
As the center of the cold air mass drifts across the area tomorrow,
look for winds to diminish during the day but temperatures will be
slow to rise with afternoon highs struggling to 10 to 15. The high
should be moving off to our east by afternoon and early evening
with our next surface low and cold front tracking across southern
Canada southwest through the Northern Plains. Early in the evening,
surface winds will be light enough for our usual tank with early
evening temperatures before we see a steady or slowly rising trend
across the north and west, while further east with a lighter wind
flow, early morning lows will dip several degrees below zero Monday
night into Tuesday morning. As the deep surface low tracks north
of Lake Superior on Tuesday, a gusty south to southwest wind should
help the mercury climb into the mid 20s far east to the low to mid
30s far west where we should be able to mix out fairly well during the
afternoon. With the better upper forcing remaining well to our north
and very limited moisture, models not showing much if any precip
associated with the boundary as it swings across our area late in
the day, except for the GFS which continues to produce a large area
of 0.01 qpf with this system. Not worth much more than a chance for
flurries and will continue with that for later in the day on Tuesday.
Then we will see another cold air mass build gradually southeast thru
midweek.
The GFS and latest ECMWF continue to show a weak shortwave racing
southeast into the Plains on Wednesday along the periphery of the
next batch of cold air for the remainder of the work week. The
GFS keeps any precip associated with this wave to our west and
south while the latest ECMWF has trended in that direction as well
but does bring in some light QPF late Wednesday/Wednesday evening.
Based on the latest westward shift with the ECMWF, will only have
slight chances Wednesday night for light snow. Colder temperatures
filter into the area again Wednesday night with early morning lows
dropping into the single digits with wind chills dropping to near
-10 by Thursday morning.
And a real surprise here, the well below normal temperatures are
expected to hold on across our area through at least the end of
the work week with daytime highs in the teens and early morning
lows dropping into the single digits with a few below zero readings
again possible early Friday morning. Both the GFS and ECMWF indicate
a significant change to the upper pattern with more of a southwesterly
flow developing over the weekend which will lead to an increasing
threat for precipitation. Models showing more agreement from what
we saw yesterday with snow chances moving in starting on Saturday
night with the threat for snow or rain on Sunday with warming
temperatures. Even seeing some better agreement with the ensemble
members with respect to the pattern change along with timing of
the precip into our area later Saturday through Sunday. Temperatures
will start to turn around on Saturday and Sunday, but still average
below the normal highs of 40 to 45 across the area for late February.
&&
.AVIATION...(For the 00Z TAFS through 00Z Monday evening)
ISSUED AT 531 PM CST SUN FEB 22 2015
VFR aviation weather Condtions are expected to prevail across the
central Illinois terminals through the 00Z TAF valid time.
Mid/high level CIGS will gradually diminish with time, with mostly
clear skies expected by midday Monday. Northerly breezes from
10-15 kts tonight will become light/variable by Monday afternoon
as high pressure builds across the area.
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
WIND CHILL ADVISORY from Midnight tonight to 9 AM CST Monday FOR
ILZ027>031-036>038-040>057-061>063-066>068-071>073.
&&
$$
SHORT TERM...Smith
LONG TERM...Smith
AVIATION...Bak
AREA FORECAST DISCUSSION
NWS TOPEKA KS
229 PM CST Sat Feb 21 2015
.SHORT TERM...(This Evening through Sunday)
Issued at 227 PM CST SAT FEB 21 2015
20Z water vapor shows a broad and deep upper trough centered over
the Hudson bay and encompassing much of North America. A couple
shortwaves within the upper trough were noted over Alberta Canada
and the Pacific Northwest moving south. At the surface, observations
show another 1044 MB ridge of high pressure over Alberta poised to
move south into the plains.
For tonight and Sunday, models agree that cold air advection will
increase as MSLP rises in response the the Arctic airmass moving
south. This is also expected to increase mid level frontogenesis
from the central Rockies into central KS. Both the NAM and GFS show
the frontogenetical band extending into parts of northeast KS late
tonight with reasonable mid level saturation. However it appears as
though the models fail to generate much QPF due to dry air in the
lower atmosphere. Feel like there is enough of a signal from the
frontogenesis to maintain a chance for measurable snow late tonight
and into Sunday morning. The better chances will be along and
southwest of a line from Concordia to Emporia. Have kept the
forecast dry across northeast KS where the low level dry air is
progged to be deeper. Limited moisture and the brief period of
vertical motion with the front suggests any snow accumulation will
be light and the forecast generally keeps amounts from around a half
inch to a dusting.
With the pressure gradient remaining fairly strong overnight, there
should be reasonable mixing of the boundary layer as surface winds
remain in the 10 to 15 MPH range. This combined with increasing cloud
cover is expected to prevent lows from plummeting tonight. The
forecast has temps falling into the teens by Sunday morning.
Continued cold air advection and limited insolation for Sunday
should hold afternoon highs in the upper teens to mid 20s.
.LONG TERM...(Sunday Night through Saturday)
Issued at 227 PM CST SAT FEB 21 2015
Active upper air pattern in the extended term as a series of systems
dive south across the western CONUS, and track east towards the
Plains. Before this occurs, strong high pressure builds into far
northeast Kansas Monday morning as winds become calm. Sided closer
to MOS guidance as they appeared to have a better handle on the
depth of the cold air with this high. Cloud cover depth will also be
slowly diminishing by morning so will keep readings in the single
digits, perhaps closer to 0 in far northeast areas in vicinity of the
ridge axis. Wind chill readings average from 0 degrees to 7 below
zero. Temps gradually recover by Tuesday as warm advection increases
from the southwest under mostly sunny skies. Based on model handling
on today`s forecast, temps could easily be a tad warmer than current
thinking in the lower to middle 40s.
Next cold front arrives late Tuesday evening into Wednesday before a
elongated shortwave trough tracks southeast from the Pac NW. Latest
runs of the GEM, GFS, and ECMWF remain persistent in light snow
developing Wednesday afternoon and exiting southward Thursday
morning along an axis of mid level frontogenesis. The system is
progressive while available moisture is low with the very cold
air mass in place; higher snow to liquid ratios however suggest the
potential for light snowfall accumulations during this time. An
additional kicker shortwave trough follows for Friday and Saturday,
lifting an additional PV anomaly through the CWA. Confidence is
lower in this system as the GFS is quicker and therefore weaker than
the slower ECMWF. Nonetheless, kept the slight to low end chances
for light snow across the area during this period. Persistent cold
advection from the north and east Wednesday through Saturday will
hold highs to the 20s and low 30s with overnight lows in the teens
to single digits.
&&
.AVIATION...(For the 18Z TAFs through 18Z Sunday Afternoon)
Issued at 1110 AM CST SAT FEB 21 2015
Don`t have much confidence in the NAM and RAP forecast soundings
since they suggest there should be broken MVFR CIGS now. As usual,
the NAM is probably overdoing the boundary layer moisture thinking
there is snow on the ground. Therefore will follow the GFS and
maintain a VFR forecast through the night. If low levels do end up
to me more saturated, there may be a small chance for some light
snow at MHK late tonight. Will have to continue monitoring
boundary layer conditions through the afternoon.
&&
.TOP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...Wolters
LONG TERM...Bowen
AVIATION...Wolters
AREA FORECAST DISCUSSION
NWS TOPEKA KS
1110 AM CST Sat Feb 21 2015
.UPDATE...
Issued at 1110 AM CST SAT FEB 21 2015
The cold air advection is obviously not as strong as previously
forecast as temps climb into the mid 40s. Even areas where there is
snow from last night are already in the upper 30s to around 40.
There is also quite a but more insolation than anticipated. The
RAP mixes the boundary layer to about 875MB. Will use this as a
first iteration in raising max temps up this afternoon. Also with
pretty high based clouds across north central KS, think flurries
this afternoon are less likely than if steep low level lapse rates
with a stratocu deck around 3 KFT were occurring.
&&
.SHORT TERM...(Through Today)
Issued at 252 AM CST SAT FEB 21 2015
Early this morning, widespread light to, at times, moderate
precipitation had overspread much of the forecast area, but has been
quickly diminishing from west to east through the overnight hours.
This precipitation was predominantly in the form of rain and
freezing rain with sleet and snow mixing in at times. As of 09Z,
precipitation was focused primarily along and southeast of I-35 with
a few areas of patchy drizzle/freezing drizzle along and east of a
line from Abilene to Marysville, but according to radar returns this
light precipitation was very isolated. Based on the short-range
model and radar trends, the bulk of the precipitation should move
east of the area by 5am with some lingering light precipitation
and/or drizzle/freezing drizzle continuing through 7am. As of 09Z,
most locations across the forecast area had temperatures of 32-34F.
Most locations should stay at or near freezing through sunrise, but
cannot rule out temperatures in north central Kansas dropping a bit
below freezing as the clouds begin to scatter out some. With
temperatures near or slightly below freezing, dangerous travel
conditions will continue into the morning hours as wet roads may
become more icy. The good news is that temperatures should rise
above freezing by 9am to 11am. Despite light northerly winds through
the day, models show a nose of warm air extending northward into
central and east central Kansas. With model soundings showing cloud
cover scattering out this morning and mid/high clouds not building
back in until late afternoon or early evening, expect high
temperatures to reach into the mid 30s to around 40 degrees from
northeast to southwest.
.LONG TERM...(Tonight through Friday)
Issued at 252 AM CST SAT FEB 21 2015
Overnight tonight, a significant snow event will be ongoing in
western Kansas, with the eastern fringe of that light snow coming
close to the highway 81 corridor. There is some weak vertical
motion in the mid levels in central KS, and forecast soundings
indicate steep boundary layer lapse rates with weak instability as
well as a deep dendritic growth zone. However, the moisture seems
to be lacking. Decided to go with a 30% or less chance of actual
accumulating snow showers in the western part of the forecast
area, but if the lift is slightly stronger it would result in
better saturation and at least some potential for minor snow
accumulations through Sunday morning. Clouds are expected to
moderate overnight low temperatures despite cold advection, with
nearly steady or slightly rising temperatures during the day on
Sunday. Sunday night then looks to be quite cold as strong surface
high pressure builds overhead...with the main uncertainty in just
how cold it will get being determined by cloud cover. Clear skies
suggest current forecast of lower single digits may be too warm
while cloudy skies would suggest a warmer forecast is warranted. A
warming trend is in store by Tuesday with sunshine in the forecast
and highs into the 40s.
Wednesday will bring another cold front and a sharp cool down
while the next chance for winter weather arrives Wednesday night.
The forcing mechanisms are a combination of weak short wave energy
ejecting from the Rocky Mountain trough, a steadily progressing
band of frontogenesis, and isentropic ascent. Model agreement is
strong regarding potential for a few inches of accumulating
snowfall, possibly encompassing much of the forecast area.
However, given recent poor model performance in this flow pattern,
would rather not get into the details of system expectations at
this time and instead focus on potential for accumulating snow.
Of increasing interest at the very end of the forecast period,
next weekend, is a potentially more organized trough to move into
the Central Plains states...and could lead to additional
accumulating winter precip.
&&
.AVIATION...(For the 18Z TAFs through 18Z Sunday Afternoon)
Issued at 1110 AM CST SAT FEB 21 2015
Don`t have much confidence in the NAM and RAP forecast soundings
since they suggest there should be broken MVFR CIGS now. As usual,
the NAM is probably overdoing the boundary layer moisture thinking
there is snow on the ground. Therefore will follow the GFS and
maintain a VFR forecast through the night. If low levels do end up
to me more saturated, there may be a small chance for some light
snow at MHK late tonight. Will have to continue monitoring
boundary layer conditions through the afternoon.
&&
.TOP WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
UPDATE...Wolters
SHORT TERM...Hennecke
LONG TERM...Barjenbruch
AVIATION...Wolters
AREA FORECAST DISCUSSION
NWS GOODLAND KS
1045 PM MST FRI FEB 20 2015
.UPDATE...
ISSUED AT 1045 PM MST FRI FEB 20 2015
UPDATE TO FORECAST SENT TO UPDATE TIMING ONGOING WINTER STORM
WARNING...ADJUST CLOUDS/TEMPS FROM LATEST OBS...AND TO REMOVE
MENTION OF -RW WORDING TO MAKE ALL -SW/ TEMPS OVER PAST FEW HOURS
HAVE DROPPED A FEW DEGREES...COLD ENOUGH TO MAKE ALL -SW THRU REST
OF THE OVERNIGHT HOURS.
&&
.SHORT TERM...(THIS EVENING THROUGH SATURDAY)
ISSUED AT 220 PM MST FRI FEB 20 2015
VISIBLE SATELLITE IMAGERY WAS INDICATING PARTLY TO MOSTLY CLOUDY
SKIES OVER THE TRI STATE AREA IN THE EARLY AFTERNOON...WITH RADAR
INDICATING SOME LIGHT PRECIPITATION BEGINNING TO OCCUR IN CENTRAL
NEBRASKA AND EASTERN COLORADO AHEAD OF AN UPPER LEVEL SHORTWAVE
TROUGH. WATER VAPOR IMAGERY SHOWED A STEADY STREAM OF MOISTURE THAT
WILL MOVE INTO THE FORECAST AREA TONIGHT...WHICH WILL BRING OVERCAST
SKIES AND CHANCES FOR PRECIPITATION.
HRRR AND RAP FORECASTS SHOW LIGHT RAIN SHOWERS BEGINNING TO AFFECT
EASTERN COLORADO BETWEEN THE 21Z AND 00Z TIME PERIOD TONIGHT...AND
THEN GRADUALLY SPREADING IN COVERAGE OVER NORTHWEST KANSAS. RAIN
WILL TRANSITION TO A RAIN/SNOW MIX AROUND 3Z...AND THEN TURN TO ALL
SNOW AFTER 6Z. PRECIPITATION AREA WILL ENTER A DRY PERIOD SHORTLY
AFTER 6Z AND LAST THROUGH 18Z SATURDAY WHERE VERY LIGHT SNOW
ACCUMULATIONS WILL OCCUR...IF ANY. MODEL GUIDANCE WAS SHOWING
ANYWHERE FROM A HALF INCH UP TO 2 INCHES FOR EASTERN COLORADO
ACCUMULATING DURING THE DAY SATURDAY. THE HIGHER GUIDANCES SEEMED TO
BE ACCUMULATING SNOW BEFORE THE 850 FREEZING LINE PASSED THROUGH AND
THE 1540 LINE FOR THE 850-700 MB THICKNESS...WHICH LED TO THE
DECISION TO BRING SNOW AMOUNTS UNDER HALF AN INCH DURING THE DAY
SATURDAY.
RAIN AND RAIN/SNOW MIXES WILL OCCUR SOUTH OF A LINE FROM CHEYENNE
WELLS COLORADO TO TRENTON NEBRASKA SATURDAY AFTERNOON...WITH SNOW
NORTH OF THIS LINE. ABOUT ANOTHER HALF OF AN INCH WILL ACCUMULATE
FOR EASTERN COLORADO BEFORE 00Z SUNDAY WHERE THE PRECIPITATION WILL
ALL CHANGE OVER TO SNOW...WHICH WILL BRING THE GREATER SNOW
ACCUMULATIONS HEADING INTO SATURDAY NIGHT. WITH A LACK OF LOWER AND
MID LEVEL JET WINDS IN COMBINATION WITH A 8 MB SURFACE PRESSURE
GRADIENT...WINDS ARE NOT EXPECTED TO GUST ABOVE 25 MPH DURING THIS
PERIOD. THEREFORE...BLOWING SNOW WILL NOT BE AN ISSUE.
.LONG TERM...(SATURDAY NIGHT THROUGH FRIDAY)
ISSUED AT 220 PM MST FRI FEB 20 2015
UPPER FLOW WILL BE WESTERLY ACROSS THE CENTRAL PLAINS SATURDAY NIGHT
AS THE BROAD TROUGH ELONGATES FROM THE WEST COAST TO THE GREAT
LAKES. AS THE TROUGH CONTINUES TO SPLIT ON SUNDAY A RIDGE WILL
START AMPLIFYING OVER THE CENTRAL PLAINS. THE RIDGING CONTINUES
OVER THE CENTRAL PLAINS MONDAY WITH A LOW OVER THE DESERT SOUTHWEST
AND THE OTHER PORTION OF THE TROUGH NORTHEAST OF THE GREAT LAKES.
THE MODELS CONTINUE TO SHOW SPLIT FLOW SUNDAY/SUNDAY NIGHT WITH
RIDGING OVER THE FA MONDAY. EXPERIENCE WITH THIS PATTERN IS NOT
FAVORABLE FOR PRECIPITATION ACROSS THE FA. GOOD DYNAMICS ARE
INDICATED FOR SATURDAY NIGHT AS A SHORTWAVE COMES THROUGH THE FLOW.
HOWEVER, IT IS DIFFICULT TO JUSTIFY THE LARGE AMOUNTS OF SNOWFALL
THE GFS AND NAM ARE PRODUCING FOR THAT 12 HOUR TIME PERIOD WHICH
EQUATES TO ABOUT AN INCH PER HOUR FOR THE ENTIRE 12 HOUR PERIOD.
PLAN TO GO SOMEWHERE UNDER THOSE AMOUNTS TO OBTAIN A MORE REASONABLE
HOURLY SNOWFALL RATE. AT THIS TIME TOTAL SNOWFALL AMOUNTS SHOULD
RANGE FROM 2 INCHES NEAR HILL CITY AND MCCOOK TO 5 TO 9 INCHES IN AN
AREA SOUTHWEST OF A LINE FROM YUMA COLORADO TO LEOTI KANSAS. THESE
AMOUNTS INCLUDE UP TO 3 INCHES FROM SUNDAY THROUGH MONDAY WHICH MAY
TURN OUT TO BE LESS THAN THAT IF THE RIDGING MENTIONED ABOVE LIMITS
THE SNOWFALL. WIND SPEEDS WILL RANGE FROM 15 TO 25 MPH SATURDAY
NIGHT WITH SPEEDS DECREASING SUNDAY/SUNDAY NIGHT.
A WINTER STORM WARNING AND WINTER WEATHER ADVISORY HAS BEEN POSTED
FOR SATURDAY EVENING THROUGH SUNDAY EVENING. (SEE DETAILS BELOW).
MIN TEMPERATURES SATURDAY NIGHT SHOULD BE IN THE TEENS. COLDER MIN
TEMPERATURES IN THE SINGLE DIGITS ABOVE ZERO AND LOW TEENS ARE
EXPECTED SUNDAY NIGHT. MAX TEMPERATURES WILL BE IN THE TEENS SUNDAY
AND AROUND 20 ON MONDAY.
IN THE EXTENDED...(MONDAY NIGHT THROUGH FRIDAY)...THE FORECAST WILL
BE DRY MONDAY NIGHT AND TUESDAY WITH LACK ANY DYNAMICS UNDER
WESTERLY FLOW. THE PART OF THE TROUGH THAT SPLITS OFF OVER THE WEST
COAST WILL MOVE INTO THE DESERT SOUTHWEST TUESDAY AND ACROSS THE
CENTRAL/SOUTHERN PLAINS WEDNESDAY. THERE WILL BE A CHANCE TO SLIGHT
CHANCE OF LIGHT SNOW AS THIS TROUGH MOVES EAST THROUGH FRIDAY.
MIN TEMPERATURES MONDAY NIGHT THROUGH WEDNESDAY NIGHT WILL BE IN THE
TEENS. MIN TEMPERATURES THURSDAY NIGHT WILL BE IN THE SINGLE DIGITS
ABOVE ZERO. MAX TEMPERATURES TUESDAY AND WEDNESDAY SHOULD RANGE FROM
THE MID 30S TO 40. MAX TEMPERATURES THURSDAY AND FRIDAY WILL BE IN
THE 20S.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SATURDAY NIGHT)
ISSUED AT 1045 PM MST FRI FEB 20 2015
BOTH TAF SITES WILL SEE MAINLY VFR CONDITIONS THRU 19Z-20Z
SATURDAY AFTERNOON. LOOKING FOR CEILINGS OVC040-060 WITH
VCSH/-SHSN DURING THIS TIME. FROM 19Z-20Z ONWARD...CONDITIONS
DETERIORATE AS A MIX OF IFR/MVFR CONDITIONS WILL PREVAIL AS AREAL
COVERAGE OF SNOW INCREASES.LOOKING FOR CEILINGS TO RANGE FROM
OVC012-025 AND VISIBILITY RANGING FROM 1 1/2SM TO 5SM AT TIMES.
WORSE CONDITIONS AFTER 00Z SUNDAY. NNW WINDS 5-10KTS WILL SHIFT TO
WNW BY 10Z SAT...THEN SHIFT TO ENE 10-20KTS BY 19Z-20Z.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...WINTER WEATHER ADVISORY FROM 6 PM SATURDAY TO MIDNIGHT CST
SUNDAY NIGHT FOR KSZ001-002-014-015-028-029.
WINTER STORM WARNING FROM 5 PM MST /6 PM CST/ SATURDAY TO 11 PM
MST /MIDNIGHT CST/ SUNDAY FOR KSZ013-027-041-042.
CO...WINTER STORM WARNING FROM 5 PM SATURDAY TO 11 PM MST SUNDAY FOR
COZ090>092.
NE...WINTER WEATHER ADVISORY FROM 5 PM MST /6 PM CST/ SATURDAY TO 11
PM MST /MIDNIGHT CST/ SUNDAY FOR NEZ079-080.
&&
$$
UPDATE...JN
SHORT TERM...MK
LONG TERM...FS
AVIATION...JN
AREA FORECAST DISCUSSION
NWS PADUCAH KY
550 PM CST SUN FEB 22 2015
.SHORT TERM...(THIS EVENING THROUGH TUESDAY NIGHT)
ISSUED AT 235 PM CST SUN FEB 22 2015
MAIN ISSUE OF CONCERN IN THE SHORT TERM IS THE WIND CHILL ADVISORY
FOR LATE TONIGHT INTO MONDAY MORNING. THE LATEST SHORT TERM
GUIDANCE KEEPS THE STRONGEST WINDS AND COLDEST TEMPERATURES ACROSS
PORTIONS OF SOUTHEAST MISSOURI AND MOST OF SOUTHERN ILLINOIS.
AFTER COLLABORATING WITH WFOS LSX AND LMK DECIDED TO EXPAND THE
ADVISORY A ROW OF COUNTIES FARTHER SOUTH ACROSS ILLINOIS AND THEN
FROM PERRY SOUTHWARD THROUGH SCOTT AND STODDARD IN MISSOURI. IT
LOOKS A LITTLE FUNKY IN MISSOURI...BUT THAT IS DUE TO THE CORE OF
STRONGER WINDS IN THAT REGION. THE WIND CHILLS CURRENTLY FORECAST
OVER SOUTHWEST INDIANA AND ADJACENT PORTIONS OF WEST KENTUCKY DO
NOT QUITE GET DOWN TO 10 BELOW...BUT LEFT THAT ALONE BECAUSE IT
WILL BE CLOSE.
ALTHOUGH WINDS ARE EXPECTED TO BE LIGHT MONDAY NIGHT...SOUTH WINDS
WILL INCREASE QUICKLY TUESDAY MORNING AND WITH THE LOWS WELL INTO
THE SINGLE DIGITS...MUCH OF SOUTHERN ILLINOIS AND SOUTHWEST
INDIANA MAY SEE SOME NEGATIVE WIND CHILLS FOR A FEW HOURS TUESDAY
MORNING. WILL GIVE THIS A MENTION IN THE HWO.
KEPT A MENTION OF FLURRIES IN THE FORECAST LATE THIS AFTERNOON AND
EVENING ROUGHLY ALONG AND SOUTH OF A LINE FROM VAN BUREN MISSOURI
TO MURRAY KENTUCKY. THE HRRR AND WRF RUNS REALLY DRY UP ANY ECHOES
AS THEY ENTER OUR AREA...AND THERE HASN`T BEEN ANY REPORTS OF SNOW
REACHING THE GROUND THIS SIDE OF KJLN. WON`T BE COMPLETELY
SURPRISED TO SEE A FEW FLURRIES...BUT MEASURABLE SNOWFALL IS
HIGHLY UNLIKELY.
TEMPERATURES HAVE REMAINED NEARLY STEADY ACROSS THE REGION
TODAY. FIGURE THAT COLD ADVECTION WILL KICK IN AS WE HEAD INTO THE
EVENING HOURS...BUT ENDED UP RAISING LOWS A BIT FOR TONIGHT. MOS
GUIDANCE IS GIVING QUITE A RANGE FOR FIRST PERIOD LOWS.
LOOKING UPSTREAM THIS AFTERNOON...IT APPEARS THAT GUIDANCE FOR
HIGHS ON MONDAY IS A BIT TOO COLD. LEANED TOWARD THE LESS COLD
NAM/MET NUMBERS...BUT IT WILL STILL STRUGGLE TO GET THROUGH THE
TEENS IN MOST LOCATIONS. WIND CHILLS WILL REMAIN IN THE SINGLE
DIGITS ABOVE ZERO THROUGH THE AFTERNOON.
NOT SURE IF MID/HIGH CLOUDS WILL BE THICK ENOUGH TO HOLD
TEMPERATURES UP MUCH MONDAY NIGHT OR NOT. WINDS SHOULD BE LIGHT OR
CALM WITH HIGH PRESSURE OVERHEAD...SO IT WILL BE ANOTHER COLD ONE.
DEFINITELY WENT TO THE COLD SIDE OF GUIDANCE MONDAY NIGHT.
SOUTHWEST WINDS WILL INCREASE ACROSS THE AREA TUESDAY...SO A
DECENT WARM UP IS FORECAST. UNFORTUNATELY WITH TEMPERATURES
STARTING OFF SO COLD...IT WILL STRUGGLE TO GET TO THE FREEZING
MARK.
A DISTURBANCE WILL DIVE SOUTHEAST THROUGH THE GREAT LAKES TUESDAY
NIGHT. THIS WILL BRING AN INCREASE IN CLOUDS AND A WEAK COLD
FRONTAL PASSAGE THROUGH OUR REGION. LOWS TUESDAY NIGHT WILL
ACTUALLY BE MILD...RELATIVELY SPEAKING. SOME LOCATIONS WILL STAY
ABOVE 20 ALL NIGHT.
.LONG TERM...(WEDNESDAY THROUGH SUNDAY)
ISSUED AT 235 PM CST SUN FEB 22 2015
ANOTHER SURGE OF COLD HIGH PRESSURE WILL BUILD SOUTHEAST WEDNESDAY
INTO WEDNESDAY NIGHT BEHIND A WEAK COLD FRONT. THE CENTER OF THE
HIGH WILL MOVE SOUTHEAST THROUGH THE END OF THE WORK WEEK AND SETTLE
OVER THE OHIO VALLEY BY 00Z SATURDAY. TEMPERATURES WILL AGAIN DROP
OFF TO EVEN COLDER THAN SEASONAL NORMALS, WITH HIGHS THURSDAY AND
FRIDAY ONLY IN THE 20S WITH LOWS IN THE SINGLE DIGITS TO MIDDLE
TEENS.
MODELS SHOW THE HIGH DRIFTING EASTWARD FOR THE EARLY PART OF THE
WEEKEND. TEMPERATURES WILL MODERATE BACK IN THE 30S AHEAD OF OUR
NEXT WEATHER SYSTEM. ECMWF AND GFS DIFFER ON TIMING AND TRACK OF A
LOW PRESSURE SYSTEM, WITH ECMWF BEING THE FASTER OF THE MODELS WITH
MORE SUBSTANTIAL QPF. ECMWF SHOWS WIDESPREAD PRECIPITATION ACROSS
THE PAH FORECAST AREA SATURDAY NIGHT, WHILE GFS JUST SHOW MINIMAL
QPF REACHING INTO OUR SOUTHERN COUNTIES LATE SATURDAY NIGHT. BY
SUNDAY BOTH MODELS SHOW DECENT QPF ACROSS THE ENTIRE PAH FA. JUST
WENT WITH SLIGHT CHANCE POPS FOR LIGHT SNOW SATURDAY NIGHT,
INCREASING TO CHANCE POPS FOR RAIN ON SUNDAY. BOTH MODELS YESTERDAY
SHOWED THIS SYSTEM AFFECTING OUR REGION FRIDAY NIGHT INTO SATURDAY,
SO WE STILL ARE FAIRLY LOW CONFIDENCE ON TIMING. THE LATER TIMING
DOES AT LEAST ALLOW SOME "WARMER" TO GET INTO OUR AREA AHEAD OF THE
SYSTEM, THUS LEADING TO LESS WINTRY PRECIP.
&&
.AVIATION...
ISSUED AT 550 PM CST SUN FEB 22 2015
BRIEF MVFR CEILINGS AT KOWB AT THE BEGINNING OF THE FORECAST
PERIOD ASSOCIATED WITH LIFT TIED WITH THE PASSAGE OF THE ARCTIC
SURGE OF COLR AIR...OTHERWISE VFR CONDITIONS SHOULD PREVAIL FOR
EACH OF THE WFO PAH TAF SITES THROUGH THE REMAINDER OF THE
FORECAST.
SHORTENED THE GRADIENT WIND PERIOD ASSOCIATED WITH THE PASSAGE OF
THE GRADIENT AT KEVV/KOWB, BUT KEPT GRADIENT WINDS LONGER OVER
KCGI/KPAH.
&&
.PAH WATCHES/WARNINGS/ADVISORIES...
IL...WIND CHILL ADVISORY FROM MIDNIGHT TONIGHT TO 9 AM CST MONDAY FOR
ILZ075>078-080>091.
MO...WIND CHILL ADVISORY FROM MIDNIGHT TONIGHT TO 9 AM CST MONDAY FOR
MOZ076-086-087-110-111.
IN...WIND CHILL ADVISORY FROM MIDNIGHT TONIGHT TO 9 AM CST MONDAY FOR
INZ081-082-085>088.
KY...WIND CHILL ADVISORY FROM MIDNIGHT TONIGHT TO 9 AM CST MONDAY FOR
KYZ010-014-015-018>020.
&&
$$
SHORT TERM...DRS
LONG TERM...RST
AVIATION...SMITH
AREA FORECAST DISCUSSION...COR TO AVIATION
NWS LOUISVILLE KY
1230 AM EST Sat Feb 21 2015
...Updated Aviation Discussion...
...Forecast Update...
Issued at 1155 PM EST Fri Feb 20 2015
Mix of sleet/snow working northeast through the area, with reports
suggesting a bit more sleet than anticipated. Will lean on that
dynamic cooling initially will turn things back to snow across the
north. To the south, low level jet is ramping up noticeably as slug
of moisture streams from the southwest. Concerned that icing
accumulations in our south may be too conservative. First, surface
temperatures are struggling to rise. 32F line remains back in
northern MS/AL with little rise noted so far in TN. 00z guidance,
both the NAM and now GFS, show surface temps lagging considerably
despite the warming aloft, and really hugs the 32/33F line for a
good portion of the morning, after 12z. Will need to evaluate the
current WS.W expiration time for the southern areas as well as ice
accumulations. Snow forecast amounts in the north look good at this
point, so no changes currently needed there.
Hydro-wise, we`ll be closely watching things but likely will need a
Flood Watch for the southern areas to address increasing concerns
for snow melt and heavy rainfall. 3 inch totals are looking more
likely, which combined with snow pack and ice accumulation, will
make for a messy and hazardous situation.
Issued at 1020 PM EST Fri Feb 20 2015
NAM has come in with a more narrow window for sleet/freezing rain,
especially along and north of the I-64 corridor. Between 12 and 15Z
Saturday it goes back to snow for the Louisville area and continues
that way through the daytime period. The 18Z GFS had that area warm,
so have kept in a chance for a mix for now. Mid shift can continue
trending the forecast as the rest of the models come in and
especially as we see the event unfold. Of note, the HRRR is coming
in with some higher snow totals than what I have up to the end of
its period at 15Z. It has done well so far with the reflectivity
field, so something to watch out for overnight.
Issued at 700 PM EST Fri Feb 20 2015
Nothing has changed as far as the complexity of this winter system
is concerned. Forecast soundings still waffle around the freezing
line at various times and depths. No one particular model is
handling the current surface temperatures across the region, so what
they have aloft is equally in question. One thing we do know is a
low-level jet will crank up across the region the rest of the night,
with a limit to how far north it can advance based on the position
of an 850mb trough swinging in. Should the limit be the I-64
corridor, we could see a longer period of snow/fzra in that
vicinity, with more snow to the north then in the current forecast.
Have trended the forecast this way, with higher totals in the north.
Will continue to make updates with QPF trends and model temp trends
as conditions warrant through the night.
.SHORT TERM (Now through Saturday Night)...
Issued at 344 PM EST Fri Feb 20 2015
...Extremely Complex Storm System Arrives Tonight Bringing A Wintry
Mess To The Region...
Arctic high that resulted in us seeing record cold temperatures over
the last few days will continue to move eastward this afternoon and
evening. In the near term, mostly cloudy skies along with
southeasterly breezes will allow temperatures to slowly warm
throughout the remainder of the afternoon and evening hours. As
expected, the model guidance is running a little too warm with
surface temperatures as the snow pack is keeping temperatures down.
NWS observations and KY Mesonet readings show temperatures in the
mid to upper teens across portions of north-central and east-central
KY with lower 20s being reported down near the KY/TN border region.
Regional radars showing precipitation developing over AR/MO. Reports
from WFO PAH indicate a mix of sleet and snow is being reported with
this activity. We expect this precipitation to move
east-northeastward and spread into southern KY later this afternoon
and evening as we continue to saturate the column from top to
bottom. This precipitation is forecast to be in the form of snow,
though some sleet could be mixed in initially until we wetbulb
down. Surface temperatures are expected to continue to slowly warm
into the lower-mid 20s.
For tonight, an area of low pressure in OK will move into AR and
then move northeastward along and mainly south of the Ohio River and
then into Ohio by Saturday evening. A very good fetch of moisture
off the Gulf of Mexico will transport copious amounts of moisture
into the lower Ohio Valley. In addition to the moisture, the
low-level jet will also transport warmer air into the region. This
warmer air will move over the top of a pre-existing cold airmass,
setting the stage for wintry weather across the region.
At this time, a very large amount of uncertainty regarding how the
lower level atmospheric temperature profile will evolve this
evening. In particular, the effects of a deep snowpack and the
ability for the models to accurately forecast the very low-level
atmospheric temperatures remains a challenge.
Our current thinking is that the impressive low-level jet structure
combined with upper level jet energetics will result in good
diffluence aloft for large scale synoptic scale lift for moderate to
occasionally heavy precipitation. Careful analysis of the thermal
profiles suggest that precipitation will initially start off as snow
across the region. However, as the jet pushes into the region, a
surge of warmer aloft will overspread the region. As is the case in
low-level jet structures, the strong air advection appears to be
strong enough to over come the snow pack in southern KY resulting in
a thermal profile that results in snow changing over to a mix of
freezing rain and sleet. Before the snow changes over, some light
accumulations, perhaps of 1-2 inches will be possible. Once the
change over takes place, moderate to heavy freezing rain with some
sleet will lead to some significant ice accumulations across
south-central KY. Our forecast is for at least 0.20 to 0.35 inches
of freezing rain falling late tonight across southern KY. By late
tonight, temperatures are expected to rise above freezing resulting
in a final transition to plain rain before sunrise Saturday. In
addition, the low-level jet will translate downward in the vertical
resulting in increasing southerly winds at the surface. This may
result in ice coated tree limbs and power lines to come down late
tonight.
Further north, the forecast becomes very complicated as the depth of
the cold air remains in question. Given the deeper snow pack across
this area...and its geographic location within the deeper core of
the arctic airmass, it appears that we`ll keep a cold enough profile
to keep snow going this evening and into the overnight period before
the warmer air aloft pushes thermal profiles warm enough to support
mainly liquid type precipitation. Because of the expected longer
duration of colder near-surface air, significant sleet and snowfall
accumulations are likely in areas along and north of the WK/BG
Parkways. Our current thinking is that that 2-4 inches will be
possible in areas from near Hartford up through the Elizabethtown
region. Further north, and mainly along and north of the I-64
corridor...which includes the Lexington and Louisville metro
regions, 4-7 inches with locally higher amounts will be possible.
Some light ice accumulations will also be possible...though it
appears that the length of mixed precipitation during the
anticipated changeover will be quite limited.
For Saturday, we expect rain to be in progress across southern KY.
Moderate to heavy rainfall will be possible across southern KY.
This rain...falling on top of accumulated ice and snow may result in
excessive runoff. More details on this can be found in the
Hydrology section below. A change over to rain is expected across
the region during the morning hours as the low-level warm air
becomes quite deep...in response to the strong low-level jet
structure. The rain will diminish in intensity during the afternoon
as the upper forcing moves east. Colder air will quickly invade
from the NW resulting in a change back to snow from NW to SE before
ending. Some minor additional snow accumulations will be possible.
On a final note, we want to emphasize that forecast confidence with
these types of systems is never high. We fully anticipate that
adjustments...some possibly significant...may be required in future
forecasts as this weather system develops this evening and
overnight. We strongly believe that we have put together the best
forecast that we can with the current data and forecaster knowledge
available. As this system evolves, we will make necessary changes to
the forecast. Residents of southern Indiana and central Kentucky
should be sure to keep up to date with the latest forecasts this
evening and overnight.
.LONG TERM (Sunday through Friday)...
Issued at 215 PM EST Fri Feb 20 2015
Will keep the long term short and sweet as all focus is on the short
term and the potentially significant winter storm to impact the Ohio
Valley. This storm will exit the region on Sunday morning, allowing
cooler air to once again filter into the region. The Canadian high
will build strongly into the Ohio Valley on Monday into Monday
night. This will bring the coolest temperatures of the long term
period, where highs Monday will struggle in the teens and lows
Tuesday morning will likely fall to near zero or below.
Temperatures will remain below normal through the rest of the
extended, with the next chance for precipitation coming Tuesday
night, where a few snow showers may affect areas mainly east of I-65.
&&
.HYDROLOGY...
Issued at 310 PM EST Fri Feb 20 2015
A strong low-level push of warmer and very moist air into the lower
Ohio Valley will result in a wintry mix changing to periods of
moderate and heavy rain Saturday, especially over south-central KY.
This could result in flooding issues for the following reasons:
1) Deep snow cover. Snow depths range from 6 to 10 inches and
currently contains roughly two-thirds to 1.25 inches of liquid
equivalent.
2) Current frost depth. The depth is around 2 inches at this time
meaning a solidly frozen ground. This would be more likely to cause
runoff as a frozen ground will be very inefficient in absorbing
water, especially given high rainfall rates.
3) Expected precipitation amounts. Even with initial precipitation
falling as snow, sleet, or freezing rain over south-central KY,
warmer surface air along with a changeover to rain should melt this
additional wintry precipitation along with some of the ambient snow
cover. Total liquid rainfall amounts of 1.5 to 2.5 inches with
locally higher amounts are expected across south-central KY.
The combination of the above factors could result in flood concerns
beginning tonight and lasting into early next week. Areal flooding
is possible, especially in low-lying areas, poor drainage areas, and
urban locations. In addition, minor flooding could develop on some
rivers early next week, such as the Green and Rolling Fork Rivers.
The strength and degree of warming with this system will have a
major impact on total rainfall amounts, the amount of snow melt, and
the overall flood potential. Stay tuned to the latest forecasts.
Those with hydro or river interests should monitor this storm system
closely.
&&
.AVIATION (06Z TAF Update)...
Issued at 1229 AM EST Sat Feb 21 2015
Very complex and low-confidence forecast as the biggest impact will
be precipitation types. Bottom line is that a wintry mess is likely,
and will affect all 3 terminals but persist for a longer period at
SDF and LEX.
A variety of winter precipitation will continue through the pre-dawn
hours as surface low pressure and an upper wave approach from the
west. BWG should see primarily FZRA through dawn, while SDF and LEX
sit on the line between FZRA to the south and SNPL to the north.
Ceilings and vsbys will be mostly MVFR but some high-end IFR cig is
not out of the question.
BWG should go over to rain by 12Z or so, and remain there for the
rest of the event.
The heaviest precipitation across the region will move in around 09Z
to 11Z, and will persist until midday as that upper wave moves
through and the surface low enters western Kentucky.
LLWS will be marginal at SDF and LEX...much stronger at BWG. Will
include WS at BWG through the dark morning hours.
A few rumbles of thunder will be possible at BWG between 06Z and
08Z, but the chances of anything significant are small enough to
omit from the already complicated TAF.
Conditions will vastly improve after 22Z-24Z today as the storm
system pulls off to the east.
&&
.LMK WATCHES/WARNINGS/ADVISORIES...
KY...WINTER STORM WARNING until 7 PM EST /6 PM CST/ this evening FOR
KYZ023>043-045>049-053>057-065>067.
WINTER STORM WARNING until 6 AM CST Saturday FOR KYZ061>064-
070>078-081-082.
IN...WINTER STORM WARNING until 7 PM EST /6 PM CST/ this evening FOR
INZ076>079-083-084-089>092.
&&
$$
Update.........ZBT/RJS
Short Term.....MJ/KJD/BJS
Long Term......KJD
Hydrology......KJD
Aviation.......13
AREA FORECAST DISCUSSION
NWS LOUISVILLE KY
1205 AM EST Sat Feb 21 2015
...Forecast Update...
Issued at 1155 PM EST Fri Feb 20 2015
Mix of sleet/snow working northeast through the area, with reports
suggesting a bit more sleet than anticipated. Will lean on that
dynamic cooling initially will turn things back to snow across the
north. To the south, low level jet is ramping up noticeably as slug
of moisture streams from the southwest. Concerned that icing
accumulations in our south may be too conservative. First, surface
temperatures are struggling to rise. 32F line remains back in
northern MS/AL with little rise noted so far in TN. 00z guidance,
both the NAM and now GFS, show surface temps lagging considerably
despite the warming aloft, and really hugs the 32/33F line for a
good portion of the morning, after 12z. Will need to evaluate the
current WS.W expiration time for the southern areas as well as ice
accumulations. Snow forecast amounts in the north look good at this
point, so no changes currently needed there.
Hydro-wise, we`ll be closely watching things but likely will need a
Flood Watch for the southern areas to address increasing concerns
for snow melt and heavy rainfall. 3 inch totals are looking more
likely, which combined with snow pack and ice accumulation, will
make for a messy and hazardous situation.
Issued at 1020 PM EST Fri Feb 20 2015
NAM has come in with a more narrow window for sleet/freezing rain,
especially along and north of the I-64 corridor. Between 12 and 15Z
Saturday it goes back to snow for the Louisville area and continues
that way through the daytime period. The 18Z GFS had that area warm,
so have kept in a chance for a mix for now. Mid shift can continue
trending the forecast as the rest of the models come in and
especially as we see the event unfold. Of note, the HRRR is coming
in with some higher snow totals than what I have up to the end of
its period at 15Z. It has done well so far with the reflectivity
field, so something to watch out for overnight.
Issued at 700 PM EST Fri Feb 20 2015
Nothing has changed as far as the complexity of this winter system
is concerned. Forecast soundings still waffle around the freezing
line at various times and depths. No one particular model is
handling the current surface temperatures across the region, so what
they have aloft is equally in question. One thing we do know is a
low-level jet will crank up across the region the rest of the night,
with a limit to how far north it can advance based on the position
of an 850mb trough swinging in. Should the limit be the I-64
corridor, we could see a longer period of snow/fzra in that
vicinity, with more snow to the north then in the current forecast.
Have trended the forecast this way, with higher totals in the north.
Will continue to make updates with QPF trends and model temp trends
as conditions warrant through the night.
.SHORT TERM (Now through Saturday Night)...
Issued at 344 PM EST Fri Feb 20 2015
...Extremely Complex Storm System Arrives Tonight Bringing A Wintry
Mess To The Region...
Arctic high that resulted in us seeing record cold temperatures over
the last few days will continue to move eastward this afternoon and
evening. In the near term, mostly cloudy skies along with
southeasterly breezes will allow temperatures to slowly warm
throughout the remainder of the afternoon and evening hours. As
expected, the model guidance is running a little too warm with
surface temperatures as the snow pack is keeping temperatures down.
NWS observations and KY Mesonet readings show temperatures in the
mid to upper teens across portions of north-central and east-central
KY with lower 20s being reported down near the KY/TN border region.
Regional radars showing precipitation developing over AR/MO. Reports
from WFO PAH indicate a mix of sleet and snow is being reported with
this activity. We expect this precipitation to move
east-northeastward and spread into southern KY later this afternoon
and evening as we continue to saturate the column from top to
bottom. This precipitation is forecast to be in the form of snow,
though some sleet could be mixed in initially until we wetbulb
down. Surface temperatures are expected to continue to slowly warm
into the lower-mid 20s.
For tonight, an area of low pressure in OK will move into AR and
then move northeastward along and mainly south of the Ohio River and
then into Ohio by Saturday evening. A very good fetch of moisture
off the Gulf of Mexico will transport copious amounts of moisture
into the lower Ohio Valley. In addition to the moisture, the
low-level jet will also transport warmer air into the region. This
warmer air will move over the top of a pre-existing cold airmass,
setting the stage for wintry weather across the region.
At this time, a very large amount of uncertainty regarding how the
lower level atmospheric temperature profile will evolve this
evening. In particular, the effects of a deep snowpack and the
ability for the models to accurately forecast the very low-level
atmospheric temperatures remains a challenge.
Our current thinking is that the impressive low-level jet structure
combined with upper level jet energetics will result in good
diffluence aloft for large scale synoptic scale lift for moderate to
occasionally heavy precipitation. Careful analysis of the thermal
profiles suggest that precipitation will initially start off as snow
across the region. However, as the jet pushes into the region, a
surge of warmer aloft will overspread the region. As is the case in
low-level jet structures, the strong air advection appears to be
strong enough to over come the snow pack in southern KY resulting in
a thermal profile that results in snow changing over to a mix of
freezing rain and sleet. Before the snow changes over, some light
accumulations, perhaps of 1-2 inches will be possible. Once the
change over takes place, moderate to heavy freezing rain with some
sleet will lead to some significant ice accumulations across
south-central KY. Our forecast is for at least 0.20 to 0.35 inches
of freezing rain falling late tonight across southern KY. By late
tonight, temperatures are expected to rise above freezing resulting
in a final transition to plain rain before sunrise Saturday. In
addition, the low-level jet will translate downward in the vertical
resulting in increasing southerly winds at the surface. This may
result in ice coated tree limbs and power lines to come down late
tonight.
Further north, the forecast becomes very complicated as the depth of
the cold air remains in question. Given the deeper snow pack across
this area...and its geographic location within the deeper core of
the arctic airmass, it appears that we`ll keep a cold enough profile
to keep snow going this evening and into the overnight period before
the warmer air aloft pushes thermal profiles warm enough to support
mainly liquid type precipitation. Because of the expected longer
duration of colder near-surface air, significant sleet and snowfall
accumulations are likely in areas along and north of the WK/BG
Parkways. Our current thinking is that that 2-4 inches will be
possible in areas from near Hartford up through the Elizabethtown
region. Further north, and mainly along and north of the I-64
corridor...which includes the Lexington and Louisville metro
regions, 4-7 inches with locally higher amounts will be possible.
Some light ice accumulations will also be possible...though it
appears that the length of mixed precipitation during the
anticipated changeover will be quite limited.
For Saturday, we expect rain to be in progress across southern KY.
Moderate to heavy rainfall will be possible across southern KY.
This rain...falling on top of accumulated ice and snow may result in
excessive runoff. More details on this can be found in the
Hydrology section below. A change over to rain is expected across
the region during the morning hours as the low-level warm air
becomes quite deep...in response to the strong low-level jet
structure. The rain will diminish in intensity during the afternoon
as the upper forcing moves east. Colder air will quickly invade
from the NW resulting in a change back to snow from NW to SE before
ending. Some minor additional snow accumulations will be possible.
On a final note, we want to emphasize that forecast confidence with
these types of systems is never high. We fully anticipate that
adjustments...some possibly significant...may be required in future
forecasts as this weather system develops this evening and
overnight. We strongly believe that we have put together the best
forecast that we can with the current data and forecaster knowledge
available. As this system evolves, we will make necessary changes to
the forecast. Residents of southern Indiana and central Kentucky
should be sure to keep up to date with the latest forecasts this
evening and overnight.
.LONG TERM (Sunday through Friday)...
Issued at 215 PM EST Fri Feb 20 2015
Will keep the long term short and sweet as all focus is on the short
term and the potentially significant winter storm to impact the Ohio
Valley. This storm will exit the region on Sunday morning, allowing
cooler air to once again filter into the region. The Canadian high
will build strongly into the Ohio Valley on Monday into Monday
night. This will bring the coolest temperatures of the long term
period, where highs Monday will struggle in the teens and lows
Tuesday morning will likely fall to near zero or below.
Temperatures will remain below normal through the rest of the
extended, with the next chance for precipitation coming Tuesday
night, where a few snow showers may affect areas mainly east of I-65.
&&
.HYDROLOGY...
Issued at 310 PM EST Fri Feb 20 2015
A strong low-level push of warmer and very moist air into the lower
Ohio Valley will result in a wintry mix changing to periods of
moderate and heavy rain Saturday, especially over south-central KY.
This could result in flooding issues for the following reasons:
1) Deep snow cover. Snow depths range from 6 to 10 inches and
currently contains roughly two-thirds to 1.25 inches of liquid
equivalent.
2) Current frost depth. The depth is around 2 inches at this time
meaning a solidly frozen ground. This would be more likely to cause
runoff as a frozen ground will be very inefficient in absorbing
water, especially given high rainfall rates.
3) Expected precipitation amounts. Even with initial precipitation
falling as snow, sleet, or freezing rain over south-central KY,
warmer surface air along with a changeover to rain should melt this
additional wintry precipitation along with some of the ambient snow
cover. Total liquid rainfall amounts of 1.5 to 2.5 inches with
locally higher amounts are expected across south-central KY.
The combination of the above factors could result in flood concerns
beginning tonight and lasting into early next week. Areal flooding
is possible, especially in low-lying areas, poor drainage areas, and
urban locations. In addition, minor flooding could develop on some
rivers early next week, such as the Green and Rolling Fork Rivers.
The strength and degree of warming with this system will have a
major impact on total rainfall amounts, the amount of snow melt, and
the overall flood potential. Stay tuned to the latest forecasts.
Those with hydro or river interests should monitor this storm system
closely.
&&
.AVIATION (00Z TAF Update)...
Issued at 615 PM EST Fri Feb 20 2015
Very complex and low-confidence forecast as the biggest impact will
be precipitation types. Bottom line is that a wintry mess is likely,
and will affect all 3 terminals but persist for a longer period in
SDF and LEX.
Precip will move in by mid-evening, initially as snow but eventually
mixing with sleet. MVFR conditions will develop, with ceilings going
fuel-alternate. Will see the warm nose push in from the south,
changing BWG over to freezing rain/sleet mix late evening and SDF
and LEX by 07-08Z. The real concern at SDF is that if this does come
down as freezing rain, it could be moderate FZRA at times. By the
time precip intensity picks up, BWG should be above freezing. Strong
low-level jetting will create wind shear issues, but not as bad as
it could be as the stronger inversion and most intense low-level jet
is above 2000 feet.
By around daybreak, look for enough cold air aloft to switch SDF and
LEX back to mostly snow, perhaps mixed with sleet. Ceilings will go
IFR at that point, but visibilities still look borderline IFR/MVFR.
Model solutions diverge from there, as the GFS really erodes the
cold air while the NAM keeps surface temps very close to freezing.
Carried an indeterminate RASN at both SDF and LEX for most of the
afternoon.
&&
.LMK WATCHES/WARNINGS/ADVISORIES...
KY...WINTER STORM WARNING until 7 PM EST /6 PM CST/ this evening FOR
KYZ023>043-045>049-053>057-065>067.
WINTER STORM WARNING until 6 AM CST Saturday FOR KYZ061>064-
070>078-081-082.
IN...WINTER STORM WARNING until 7 PM EST /6 PM CST/ this evening FOR
INZ076>079-083-084-089>092.
&&
$$
Update.........ZBT/RJS
Short Term.....MJ/KJD/BJS
Long Term......KJD
Hydrology......KJD
Aviation.......RAS
AREA FORECAST DISCUSSION...UPDATED
NWS SHREVEPORT LA
1043 AM CST SAT FEB 21 2015
.DISCUSSION...
AS OF 16Z...THE COLD FRONT WAS ROUGHLY LOCATED ALONG THE I-30
CORRIDOR. A LINE OF CONVECTION HAS BEEN TRYING TO DEVELOP ALONG
AND AHEAD OF THE FRONT FROM NEAR KCRS NEWD TO KTXK AND KLZK. SOME
OF THIS CONVECTION...MAINLY IN SRN AND CNTRL AR...IS ACTUALLY
BEHIND THE FRONT. SCT SHWRS ALSO PERSIST ACROSS MUCH OF THE CWA
WELL IN ADVANCE OF THE MAIN BAND OF TSTMS. COMBINED WITH THE
PERSISTENT CLOUD COVER...THIS IS HELPING TO LIMIT INSTABILITY.
CONVECTION ALONG THE FRONT WILL LIKELY BE IN A LINEAR MODE TODAY
AND A FEW SVR STORMS ARE STILL POSSIBLE WITH DAMAGING WINDS THE
PRIMARY THREAT. IF ANY LOCALIZED BACKING OF THE LOW LVL WINDS
OCCUR AHEAD OF THE FRONT...AN ISOLATED TORNADO CANNOT BE RULED
OUT.
HAVE UPDATED MOST OF THE GRIDS THROUGH 00Z BASED ON LATEST FRONT
POSITION...OBS AND RADAR TRENDS. UPDATED TEXT PRODUCTS HAVE BEEN
SENT. /09/
&&
.PREV DISCUSSION... /ISSUED 554 AM CST SAT FEB 21 2015/
AVIATION...
LOTS OF AVIATION CONCERNS TODAY AND TONIGHT ACROSS OUR TERMINAL
LOCATIONS. MVFR CEILINGS ARE THE PREVAILING CATEGORY THIS MORNING
AS MOISTURE CONTINUES TO STREAM NORTHWARD WITH THE AID OF 50+ KTS
AT 3KFT PER KSHV VWP DATA. ISENTROPIC LIFT IS RESULTING IN SOME
DRIZZLE AND/OR LIGHT RAIN IN THE VCNTY OF THE ELD/SHV AND LFK
TERMINALS. MEANWHILE...SCATTERED CONVECTION IS BEGINNING TO DEVELOP
JUST SOUTH OF A WARM FRONT ACROSS PORTIONS OF NE TX/SE OK AND SW
AR IN THE VCNTY OF THE TXK/ELD TERMINALS.
HAVE TIMED FRONTAL PASSAGE ACCORDING TO THE LATEST HRRR DATA WHICH
SHOWS THE FRONT INTO THE TXK/TYR TERMINALS BY 18Z...INTO THE
SHV/ELD TERMINALS BY 21Z AND INTO THE LFK/MLU TERMINALS NEAR THE
00Z HOUR. WINDS AHEAD OF THIS FRONT WILL REMAIN STRONG WITH
SUSTAINED WINDS NEAR 15KTS WITH HIGHER GUSTS. GRADIENT ACTUALLY
APPEARS TO RELAX SLIGHTLY JUST AHEAD OF FRONTAL PASSAGE. WARM
SECTOR WILL BECOME UNSTABLE TODAY AHEAD OF THE FRONTAL BOUNDARY
AND WITH FRONTAL FORCING...EXPECT TO SEE A LINEAR LINE OF
THUNDERSTORMS DEVELOPING ALONG THE FRONT ITSELF.
EXPECT THE POSSIBILITY OF IFR CEILINGS BEHIND THE FRONTAL BOUNDARY
LATE TODAY INTO TONIGHT WITH SOME POST FRONTAL CONVECTION AS WELL
GIVEN THE FACT THAT THE 850MB FRONT IS MUCH SLOWER TO MOVE INTO
THE REGION TONIGHT.
13
PREV DISCUSSION... /ISSUED 447 AM CST SAT FEB 21 2015/
DISCUSSION...
NWD MOVG WARM FRONTAL BOUNDARY HAS STALLED OUT FOR TIME
BEING...OVER EXTREME NORTHERN TIER OF CWA. COLD AIRMASS EXTREMELY
SHALLOW...AS SEEN BY WILD TEMP FLUCTUATIONS WITHIN THE VALLEYS AND
RIDGES OF THE OUACHITA MTNS. STG LOW LVL JET OF 50+ KNOTS FROM SW
HAS ALLOWED LAKE WIND ADVISORY CRITERIA TO MAINTAIN ACROSS WESTERN
CWA OVERNIGHT. WITH SFC TEMPS WARMING TO LOWER TO MID 70S...AND DEWPOINTS
TO CONTINUE TO RISE INTO 60S IN WARM SECTOR...EXPECT TSTMS SOUTH
OF I-30 TO POSSIBLY BECOME STG AS SOME DIURNAL HTG TO OCCUR BEFORE
COLD FRONTAL PASSAGE. THIS FRONT WILL REACH THE I-20 CORRIDOR BY
LATE IN AFTN...AND CONVECTION TO TRANSITION TO COLD RAIN WITH
FROPA. CLOUDY SKIES AND CAA ON SUNDAY WILL PREVENT MUCH WARMING
FROM OCCURRING WITH SAT NIGHT LOWS FALLING MOSTLY INTO UPPER 30S
AND LOWER 40S. APPEARS ENOUGH MOISTURE LEFT WITH POST FRONTAL
SHORT WAVE ARRIVING SUNDAY NIGHT FOR RAIN TO TRANSITION TO FRZG
RAIN IN FALLING TEMPS AND VERY SHALLOW COLD AIRMASS MENTIONED EARLIER.
SECOND SHORT WAVE ARRIVING TUESDAY APPEARS TO CONTAIN ENOUGH
MOISTURE FOR PRECIP TO CONTINUE. WITH WARM NOSE AND SFC BASED
INVERSION WEAKENING BY THEN...BETTER POTENTIAL FOR SNOW AND
SLEET...AND SLEET WILL WORK ITS WAY DOWN THRU MOST OF CWA. GFS IS
OBVIOUSLY TOO COLD...KEEPING DAYTIME TEMPS IN 20S MOST OF AREA SO
LEANING CLOSER TO NAM. DEEPENING UPPER TROUGH TO WEST IN EXTENDED
WILL YIELD MORE PRECIP LATER IN WEEK...WHICH MAY WELL ALSO BECOME
A WINTRY MIX AS ARCTIC AIRMASS WILL REMAIN ENTRENCHED OVER THE AREA.
/VII/.
&&
.PRELIMINARY POINT TEMPS/POPS...
SHV 71 42 47 30 34 / 60 40 30 50 60
MLU 70 41 49 29 34 / 70 60 30 50 60
DEQ 61 37 41 24 31 / 50 10 30 50 60
TXK 67 38 43 27 31 / 60 20 30 50 60
ELD 66 37 44 25 31 / 70 40 30 50 60
TYR 66 44 45 31 34 / 40 40 40 50 70
GGG 68 43 46 30 34 / 50 40 40 50 70
LFK 72 50 54 35 37 / 40 40 40 40 70
&&
.SHV WATCHES/WARNINGS/ADVISORIES...
AR...NONE.
LA...NONE.
OK...NONE.
TX...NONE.
&&
$$
09
AREA FORECAST DISCUSSION
NWS SHREVEPORT LA
554 AM CST SAT FEB 21 2015
.AVIATION...
LOTS OF AVIATION CONCERNS TODAY AND TONIGHT ACROSS OUR TERMINAL
LOCATIONS. MVFR CEILINGS ARE THE PREVAILING CATEGORY THIS MORNING
AS MOISTURE CONTINUES TO STREAM NORTHWARD WITH THE AID OF 50+ KTS
AT 3KFT PER KSHV VWP DATA. ISENTROPIC LIFT IS RESULTING IN SOME
DRIZZLE AND/OR LIGHT RAIN IN THE VCNTY OF THE ELD/SHV AND LFK
TERMINALS. MEANWHILE...SCATTERED CONVECTION IS BEGINNING TO DEVELOP
JUST SOUTH OF A WARM FRONT ACROSS PORTIONS OF NE TX/SE OK AND SW
AR IN THE VCNTY OF THE TXK/ELD TERMINALS.
HAVE TIMED FRONTAL PASSAGE ACCORDING TO THE LATEST HRRR DATA WHICH
SHOWS THE FRONT INTO THE TXK/TYR TERMINALS BY 18Z...INTO THE
SHV/ELD TERMINALS BY 21Z AND INTO THE LFK/MLU TERMINALS NEAR THE
00Z HOUR. WINDS AHEAD OF THIS FRONT WILL REMAIN STRONG WITH
SUSTAINED WINDS NEAR 15KTS WITH HIGHER GUSTS. GRADIENT ACTUALLY
APPEARS TO RELAX SLIGHTLY JUST AHEAD OF FRONTAL PASSAGE. WARM
SECTOR WILL BECOME UNSTABLE TODAY AHEAD OF THE FRONTAL BOUNDARY
AND WITH FRONTAL FORCING...EXPECT TO SEE A LINEAR LINE OF
THUNDERSTORMS DEVELOPING ALONG THE FRONT ITSELF.
EXPECT THE POSSIBILITY OF IFR CEILINGS BEHIND THE FRONTAL BOUNDARY
LATE TODAY INTO TONIGHT WITH SOME POST FRONTAL CONVECTION AS WELL
GIVEN THE FACT THAT THE 850MB FRONT IS MUCH SLOWER TO MOVE INTO
THE REGION TONIGHT.
13
&&
.PREV DISCUSSION... /ISSUED 447 AM CST SAT FEB 21 2015/
DISCUSSION...
NWD MOVG WARM FRONTAL BOUNDARY HAS STALLED OUT FOR TIME
BEING...OVER EXTREME NORTHERN TIER OF CWA. COLD AIRMASS EXTREMELY
SHALLOW...AS SEEN BY WILD TEMP FLUCTUATIONS WITHIN THE VALLEYS AND
RIDGES OF THE OUACHITA MTNS. STG LOW LVL JET OF 50+ KNOTS FROM SW
HAS ALLOWED LAKE WIND ADVISORY CRITERIA TO MAINTAIN ACROSS WESTERN
CWA OVERNIGHT. WITH SFC TEMPS WARMING TO LOWER TO MID 70S...AND DEWPOINTS
TO CONTINUE TO RISE INTO 60S IN WARM SECTOR...EXPECT TSTMS SOUTH
OF I-30 TO POSSIBLY BECOME STG AS SOME DIURNAL HTG TO OCCUR BEFORE
COLD FRONTAL PASSAGE. THIS FRONT WILL REACH THE I-20 CORRIDOR BY
LATE IN AFTN...AND CONVECTION TO TRANSITION TO COLD RAIN WITH
FROPA. CLOUDY SKIES AND CAA ON SUNDAY WILL PREVENT MUCH WARMING
FROM OCCURRING WITH SAT NIGHT LOWS FALLING MOSTLY INTO UPPER 30S
AND LOWER 40S. APPEARS ENOUGH MOISTURE LEFT WITH POST FRONTAL
SHORT WAVE ARRIVING SUNDAY NIGHT FOR RAIN TO TRANSITION TO FRZG
RAIN IN FALLING TEMPS AND VERY SHALLOW COLD AIRMASS MENTIONED EARLIER.
SECOND SHORT WAVE ARRIVING TUESDAY APPEARS TO CONTAIN ENOUGH
MOISTURE FOR PRECIP TO CONTINUE. WITH WARM NOSE AND SFC BASED
INVERSION WEAKENING BY THEN...BETTER POTENTIAL FOR SNOW AND
SLEET...AND SLEET WILL WORK ITS WAY DOWN THRU MOST OF CWA. GFS IS
OBVIOUSLY TOO COLD...KEEPING DAYTIME TEMPS IN 20S MOST OF AREA SO
LEANING CLOSER TO NAM. DEEPENING UPPER TROUGH TO WEST IN EXTENDED
WILL YIELD MORE PRECIP LATER IN WEEK...WHICH MAY WELL ALSO BECOME
A WINTRY MIX AS ARCTIC AIRMASS WILL REMAIN ENTRENCHED OVER THE AREA.
/VII/.
&&
.PRELIMINARY POINT TEMPS/POPS...
SHV 72 42 47 30 34 / 60 40 30 50 60
MLU 74 41 49 29 34 / 60 60 30 50 60
DEQ 66 37 41 24 31 / 40 10 30 50 60
TXK 67 38 43 27 31 / 70 20 30 50 60
ELD 70 37 44 25 31 / 60 40 30 50 60
TYR 71 44 45 31 34 / 50 40 40 50 70
GGG 72 43 46 30 34 / 50 40 40 50 70
LFK 74 50 54 35 37 / 50 40 40 40 70
&&
.SHV WATCHES/WARNINGS/ADVISORIES...
AR...LAKE WIND ADVISORY UNTIL 9 AM CST THIS MORNING FOR THE FOLLOWING
ZONES: ARZ070-071.
LA...LAKE WIND ADVISORY UNTIL 9 AM CST THIS MORNING FOR THE FOLLOWING
ZONES: LAZ001-002-010-017.
OK...NONE.
TX...LAKE WIND ADVISORY UNTIL 9 AM CST THIS MORNING FOR THE FOLLOWING
ZONES: TXZ096-097-108>112-124>126-136>138-149>153-165>167.
&&
$$
VII/13
AREA FORECAST DISCUSSION
NWS WAKEFIELD VA
942 PM EST SUN FEB 22 2015
.SYNOPSIS...
A FRONTAL BOUNDARY STALLS ACROSS THE CAROLINA COAST TONIGHT AND
MONDAY AS A WEAK AREA OF LOW PRESSURE MOVES EAST ALONG IT. AN
ARCTIC COLD FRONT WILL PUSH ACROSS THE AREA MONDAY MORNING. HIGH
PRESSURE RETURNS THROUGH MID WEEK.
&&
.NEAR TERM /THROUGH MONDAY/...
LOCALLY DENSE FOG HAS FORMED FM PORTIONS OF THE ERN SHORE TO CSTL
SECTIONS IN SE VA (AND OVR THE ADJACENT WTRS). HAVE COVERED THE
FOG W/ A SPECIAL WEATHER STATEMENT ON LAND...AND DENSE FOG
ADVISORY OVR THE WTRS (UNTIL ABT 09Z/23). OTRW...VRB CLDS ACRS THE
AREA WILL TEMPS CONTG A SLOW DROP THROUGH THE 30S/40S. SOME DRIER
AIR WILL BE SPREADING SLOWLY INTO THE RGN FM THE NW BY LT
TNGT...SO THE FOG IS XPCD TO DISSIPATE. LO TEMPS MNLY 30 TO 35F.
18Z/22 GFS AND RUC SUGGEST A LITTLE BETTER CHC FOR A PD OF LGT
PCPN OVR SRN VA/NE NC LT TNGT INTO MID/LT MRNG HRS MON. HAVE
ADJUSTED POPS UP ACRS SRN/SE VA AND NE NC. ADDED 30-50% CHC SN N
OF THE VA/NC BORDER TO ABT FVX-LFI/SRN PORTION OF ERN SHORE...W/
PSBL ACCUM LESS THAN 1 INCH. MIXED PTYPC PSBL ACRS NE NC...PTNTLLY
BECOMING SN BEFORE ENDING LT MON MRNG/EARLY AFTN. ANY PCPN WILL BE
ARRIVING W/ LO LVL CAA INCRSG AS NEXT CDFNT PUSHES THROUGH THE RGN.
TEMPS ONLY RISE A FEW DEGREES FROM 12Z READINGS THEN REMAIN
STEADY OR SLOWLY FALL BACK INTO THE 20S IN THE AFTRN AS THE NEXT
ARCTIC HIGH PRESSURE BUILDS INTO THE REGION ON GUSTY N-NW WINDS.
&&
.SHORT TERM /MONDAY NIGHT THROUGH WEDNESDAY/...
MSTLY CLR TO PT CLDY SKIES MONDAY NIGHT AS RIDGE AXIS BUILDS OVER
THE FA. RECORD LOWS IN JEOPARDY AS WINDS WEST OF THE BAY DECOUPLE
ALLOWING FOR GOOD RADIATIONAL COOLING. WIND CHILL VALUES ALONG THE
COAST ARE EXPECTED TO REMAIN ABOVE ADVISORY CRITERIA. ONLY THING
THAT MIGHT PREVENT THE RECORDS FROM FALLING IS SOME MID / HIGH
LEVEL CLOUDS NOTED IN TSCTNS. LOWS 5-10 EASTERN SHORE...10-15
ELSEWHERE EXCEPT M-U TEENS SERN BEACH AREAS. SEE CLI SECTION BELOW
FOR TUES RECORD TMPS.
PT TO MSTLY SUNNY TUESDAY. COLD AS H85 TMPS ONLY SUPPORT HIGHS IN THE
U20S-M30S. MODELS SHOW WEAK AREA OF LOW PRESSURE (TROF) OFF THE SERN
COAST TUESDAY NIGHT. EXPECT THE SGNFCNT MOISTURE TO STAY ALONG OR
EAST OF THE CAROLINA COAST. WENT WITH A BIT MORE CLOUD COVERAGE OVER
THE EAST THUS PT TO MSTLY CLDY SKIES AS AN UPPER LEVEL TROF SWINGS
ACROSS THE NERN STATES. NOT AS COLD AS SW WINDS HOLD LOWS IN THE 20S.
THE LOW PULLS FURTHER EAST AND OFF THE COAST WED. MILDER UNDER PT TO
MSTLY SUNNY SKIES. WEST WINDS ALLOW TMPS TO WARM BACK INTO THE 40S.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/...
THE LONG TERM WILL BRING SUBTLE CHANGES TO THE WEATHER. WHILE BELOW
NORMAL TEMPERATURES WILL CONTINUE...THE COLD WILL NOT BE AS BRUTAL
AS THE PAST WEEK. A SPLIT FLOW PATTERN WILL BRING A MORE ACTIVE
SOUTHERN STREAM WILL BRING LOW PRESSURE SYSTEMS PASSING TO THE SOUTH
OF THE AREA BUT WIDESPREAD PRECIPITATION IS NOT EXPECTED.
FOLLOWING THE PASSAGE OF AN ARCTIC COLD FRONT MID WEEK...A LOW
PRESSURE SYSTEM MOVES OFF THE SOUTHEAST COAST WEDNESDAY NIGHT. PCPN
SHOULD GENERALLY BE TO THE SOUTH OF THE AREA. GUIDANCE HAS VARIOUS
CHANCES FOR PCPN SATURDAY THROUGH SUNDAY WITH RAIN OR SNOW SATURDAY
AND SATURDAY NIGHT AND RAIN SUNDAY. A COLD FRONT APPROACHES FROM THE
WEST LATE IN THE WEEKEND. KEPT POPS AT 30 PERCENT DURING THE
WEEKEND.
HIGH TEMPERATURES IN THE UPR 20S TO 30S THURSDAY AND FRIDAY WARM TO
THE UPR 40S AND 50S BY SUNDAY. LOWS WILL BE MAINLY IN THE
20S...WARMING TO THE MID 30S NEAR THE SE VA/NE NC COAST SUNDAY
MORNING.
&&
.AVIATION /02Z MONDAY THROUGH FRIDAY/...
COLD FRONT ALONG THE NC/VA BORDER AND NE FLOW BEHIND THE BNDRY HAS
BROUGHT SOME DENSE FOG TO COASTAL AREAS. THIS HAS MOSTLY AFFECTED
AREAS ALONG THE PENINSULA TO THE EASTERN SHORE. EXPECT THE FOG TO
IMPROVE BY AROUND MIDNIGHT AS THE FRONT SHIFTS A LITTLE FARTHER
SOUTH AND A LITTLE DRIER AIR MOVES IN.
A LOW PRES SYSTEM WILL MOVE ALONG THE FRONT AND OUT OF MS/AL
OVERNIGHT AND OFF THE NC COAST BY EARLY MORNING. THE LOW WILL
BRING SOME WINTRY PCPN TO THE AREA FROM ABOUT SUNRISE TO THE EARLY
AFTN. A MIX OF -RA/FZRA/-SN/PL WILL AFFECT THE TAF SITES DURING THE
MORNING WITH MOSTLY MVFR/IFR CONDS PREVAILING INTO THE AFTN. THE
BEST CHC FOR FZRA/PL WILL BE ALONG THE SOUTHERN BORDER OF VA AND
OVER NC.
OUTLOOK...BECOMING VFR DURING THE AFTN AND MAINLY DRY...COLD AND VFR
WEATHER EXPECTED TUE AND WED.
&&
.MARINE...
HAVE DECIDED TO ISSUE A SCA FOR THE ENTIRE WTRS STARTING LATE TNGT
AND LASTING THRU MON EVENG/MON NGT. THERE IS STILL POTENTIAL FOR
GALE GUSTS DURING LATE MON MORNG/AFTN TIMEFRAME AT THE MOUTH OF THE
BAY AND CSTL WTRS S OF CAPE CHARLES...DUE TO STRONGER PRESSURE
GRADIENT IN THIS AREA. BUT...FOR NOW WENT WITH A STRONG SCA IN THESE
ZNS...AND WILL LET MIDNGT SHIFT DECIDE WHETHER TO UPGRADE TO A GALE
WARNG BASED ON NEWER GUIDANCE. BASED ON 12Z/22 GUIDANCE...COLD
ADVECTION REMAINS DELAYED BEHIND FRONT...WHICH WAS PUSHING OFF THE
CST LATE THIS AFTN. THIS MEANS NORTHERLY WIND SURGE WON`T BEGIN
UNTIL LATE TNGT/EARLY MON MORNG. SURGE WILL CONTINUE THRU
MON...BEFORE WINDS DIMINISH MON NGT. SEAS WILL BLD TO 5-9 FT AND
WAVES WILL BLD TO 3-5 FT IN THE CHES BAY. HI PRES BLDS ACRS THE
REGION MON NGT/TUE...THEN MOVES OFFSHR TUE AFTN/TUE NGT...AHEAD OF
NEXT ARCTIC FRONT. THIS FRONT WILL CROSS THE AREA ON WED...FOLLOWED
BY ANOTHER SURGE OF COLD AIR FOR THU AND FRI.
&&
.TIDES/COASTAL FLOODING...
CONTINUED THE LOW WATER ADSY FOR THE LOWER BAY AND CSTL WATERS
THROUGH 7 PM.
&&
.CLIMATE...
NORFOLK`S LOW TEMPERATURE OF 9 DEGREES ON FEB 20 WAS THE COLDEST
FOR SO LATE IN THE SEASON. THE MINUS 4 DEGREE READING AT SALISBURY
ON FEB 21ST IS NOW THE ALL TIME LOW FOR THE MONTH OF FEBRUARY.
THE CURRENT AVERAGE TEMPERATURES FOR THE MONTH OF FEBRUARY AT
BOTH RICHMOND AND NORFOLK PLACE THEM IN THE TOP 10 COLDEST. WITH
ADDITIONAL COLD TEMPERATURES EXPECTED NEXT WEEK...IT IS VERY
LIKELY THAT BOTH SITES WILL HAVE AVERAGE TEMPERATURES IN THE TOP
10 COLDEST FEBRUARYS ON RECORD...PERHAPS IN THE TOP 5 COLDEST.
RECORD LOW TEMPERATURES FOR TUESDAY 2/24:
RIC...11 IN 1914
ORF...16 IN 1947
SBY...10 IN 1934
ECG...19 IN 1947
&&
.AKQ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
NC...NONE.
VA...NONE.
MARINE...SMALL CRAFT ADVISORY FROM 4 AM TO 7 PM EST MONDAY FOR
ANZ635>638.
DENSE FOG ADVISORY UNTIL 4 AM EST MONDAY FOR ANZ631-632-634-
638-650-652-654-656.
SMALL CRAFT ADVISORY FROM 4 AM MONDAY TO MIDNIGHT EST MONDAY
NIGHT FOR ANZ630>634-650-652-654.
SMALL CRAFT ADVISORY FROM 4 AM MONDAY TO 6 AM EST TUESDAY FOR
ANZ656-658.
&&
$$
SYNOPSIS...ALB/MPR
NEAR TERM...ALB/MPR
SHORT TERM...MPR
LONG TERM...LSA
AVIATION...JEF/LSA
MARINE...LSA
TIDES/COASTAL FLOODING...
CLIMATE...
AREA FORECAST DISCUSSION
NWS BALTIMORE MD/WASHINGTON DC
949 AM EST SAT FEB 21 2015
.SYNOPSIS...
LOW PRESSURE WILL PASS THROUGH THE OHIO VALLEY LATE THIS AFTERNOON
AND EVENING. THE COLD FRONT ASSOCIATED WITH THE LOW WILL PASS
THROUGH THE AREA SUNDAY AND CANADIAN HIGH PRESSURE WILL BUILD
OVERHEAD EARLY NEXT WEEK. A COLD FRONT WILL PASS THROUGH THE AREA
WEDNESDAY AND HIGH PRESSURE WILL RETURN FOR LATE NEXT WEEK.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
SNOW WILL CONTINUE TO MOVE EASTWARD THIS MORNING IMPACTING THE
BALTIMORE/WASHINGTON DC METROS BY NOON. REPORTS OF A HALF OF AN
INCH TO AN INCH AN HOUR RATES HAVE BEEN REPORTED IN THIS INTIAL
BAND MOVING ACROSS THE BLUE RIDGE MOUNTAINS THIS MORNING.
A SHORTWAVE TROUGH HAS MOVED INTO THE NORTHERN OHIO VALLEY WHILE
WARM AIR ADVECTION CONTINUES THIS MORNING. THE ENTIRE COLUMN
ACROSS THE MID-ATLANTIC IS BELOW FREEZING AT THIS TIME AND
THEREFORE SNOW IS EXPECTED ACROSS THE REGION.
SNOW WILL CONTINUE TO MOVE FROM SW TO NE TODAY. MODERATE TO HEAVY
SNOW IS EXPECTED THROUGH THE AFTERNOON. HIGH REFLECTIVITY BEING
REPORTED ACROSS E KY AND W WV IS BELIEVED TO BE IN RESPONSE TO
MELTING ALOFT. THE LATEST HRRR SHOWS THE HEAVIEST AXIS OF PRECIP
TO BE LOCATED FROM THE VA HIGHLANDS/HIGHLAND COUNTY VA TO NOVA TO
NE MD. WINTER WEATHER WARNINGS AND ADVISORIES ARE IN EFFECT AT
THIS TIME. PLEASE SEE THE PRODUCTS FOR MORE INFORMATION REGARDING
A SPECIFIC LOCAL.
PREVIOUS DISCUSSION...
DESPITE THE STRONG WARM ADVECTION...THERMAL PROFILES SUGGEST THAT
THE AIRMASS WILL BE COLD ENOUGH FOR SNOW FOR MOST OF TODAY.
HOWEVER...WARMER AIR WILL WORK ITS WAY IN ALOFT LATER THIS AFTERNOON
AND EVENING...CAUSING PRECIPITATION TO CHANGE OVER TO A WINTRY MIX
BEFORE FINALLY ENOUGH WARM AIR EVENTUALLY CAUSES PRECIPITATION TO
CHANGE TO ALL RAIN. THERE IS STILL SOME UNCERTAINTY AS TO HOW MUCH
SNOW WILL FALL TODAY BEFORE THE CHANGE OVER. HOWEVER...GIVEN THE
STRONG FORCING AND ABUNDANT MOISTURE WITH THIS SYSTEM THE CURRENT
FORECAST HAS LEANED TOWARD THE HIGHER SNOWFALL TOTALS...THINKING
THAT MODERATE TO HEAVY SNOW CAN DEVELOP LATE THIS MORNING AND
AFTERNOON BEFORE THE CHANGEOVER OCCURS. A WINTER STORM WARNING IS IN
EFFECT FOR BALTIMORE...THE NORTHERN AND WESTERN SUBURBS OF
WASHINGTON...AND FOR LOCATIONS ALONG AND WEST OF THE BLUE RIDGE
MOUNTAINS. A WINTER WEATHER ADVISORY IS IN EFFECT FOR THE REST OF
THE CWA. HAZARDOUS TRAVEL IS EXPECTED ACROSS THE ENTIRE AREA WITH
THE WORST CONDITIONS EXPECTED LATE THIS MORNING THROUGH THIS
EVENING. ALSO...KEEP IN MIND THAT EVEN WHEN TEMPERATURES RISE ABOVE
FREEZING TONIGHT...PAVEMENT TEMPS MAY BE SLOWER TO RESPOND DUE TO
THE RECENT COLD CONDITIONS.
THE DRY SLOT WILL WORK ITS WAY INTO THE AREA LATE TONIGHT AND THIS
MAY END PRECIPITATION ACROSS NORTHERN MARYLAND...NORTHERN VIRGINIA
AND EASTERN WEST VIRGINIA. HOWEVER...TEMPS MAY HOVER CLOSE TO
FREEZING ACROSS THESE AREAS. FARTHER SOUTHEAST TOWARD SOUTHERN
MARYLAND AND THE VIRGINIA PIEDMONT...RAIN WILL CONTINUE ALL NIGHT.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM SUNDAY/...
THE DRY SLOT WILL CONTINUE TO OVERSPREAD MOST OF THE AREA
SUNDAY...CAUSING PRECIPITATION TO END. HOWEVER...RAIN WILL CONTINUE
ACROSS SOUTHERN MARYLAND INTO THE VIRGINIA PIEDMONT THROUGH MIDDAY
BEFORE EVENTUALLY TAPERING OFF. LOW CLOUDS AND AREAS OF FOG EARLY
SUNDAY SHOULD BURN OFF DURING THE DAY AS DRIER AIR WORKS ITS WAY
INTO THE REGION. MAX TEMPS WILL RANGE FROM THE MID TO UPPER 30S IN
NORTHERN MARYLAND...TO THE MIDDLE 40S IN CENTRAL VIRGINIA.
THE COLD FRONT ASSOCIATED WITH THE LOW WILL PASS THROUGH OUR AREA
SUNDAY AFTERNOON.
&&
.LONG TERM /SUNDAY NIGHT THROUGH FRIDAY/...
REGION REMAINS POSITIONED UNDER UPPER LEVEL TROUGH THROUGH THE
COMING WEEK. LOW PRESSURE EXITS BY 00Z MONDAY AS STRONG CANADIAN
HIGH BUILDS SOUTH INTO THE CENTRAL PLAINS BY MONDAY MORNING. MID
ATLANTIC WILL REMAIN ON THE EASTERN PERIPHERY OF THE HIGH AS IT
SINKS TO THE SOUTH AND EVENTUALLY TURNS EAST OVER THE SOUTHEASTERN
US AHEAD OF THE NEXT APPROACHING LOW PRESSURE SYSTEM. AS SUCH...FOR
MONDAY AND TUESDAY HAVE DRY CONDITIONS IN PLACE. CAA PUSHES 850MB
TEMPS DOWN TO AROUND 15 BELOW ZERO CELSIUS...KEEP TEMPS WELL BELOW
NORMAL. DESPITE CLEARING SKIES...WILL SEE TEMPS ONLY RISE A COUPLE
OF DEGREES DURING THE DAY MONDAY. LOWS TEMPS MONDAY NIGHT COULD SEE
SOME AREAS ACROSS THE WESTERN CWA DROPPING BELOW ZERO...AND SINGLE
DIGITS ABV ZERO FOR MOST OF THE REMAINING AREA. EXPECTING THE
PRESSURE GRADIENT BETWEEN THE HIGH AND THE DEPARTING LOW TO HAVE
SLACKEN BY MON NIGHT...ALONG WITH THE CAA WEAKENING. AS SUCH...WINDS
WILL BE ON THE LIGHTER END...THOUGH COULD STILL SEE WIND CHILLS INTO
THE TEENS BELOW ZERO FOR THE ALLEGHENY FRONT...WITH OTHER PORTIONS
OF THE SHENANDOAH VALLEY REACHING SINGLE DIGITS BELOW ZERO.
CLOSED LOW ALOFT PIVOTS INTO SOUTHEASTERN CANADA BY TUESDAY
NIGHT...WITH ACCOMPANYING SFC LOW SWINGING INTO THE GREAT LAKES AND
INTO THE NORTHEAST LATE TUES THROUGH WED. COLD FRONT SWINGS THROUGH
THE MID ATLANTIC DURING THIS PERIOD...THOUGH SOME QUESTION AS TO THE
EXTENT OF THE PCPN TOTALS. 00Z GFS A BIT FURTHER SOUTH WITH
SHORTWAVE ENERGY...WHILE THE ECMWF HAS A MORE PRONOUNCED SOUTHERN
STREAM WAVE THAT PUSHES KEEPS THE NORTHERN STREAM NORTH OF THE
MASON-DIXON. WILL HOLD WITH SLIGHT CHC POPS FOR NOW DUE TO THE
DIVERGENCE IN SOLUTIONS....EXCEPT WESTERN ALLEGHENY WHICH CAN EXPECT
UPSLOPING SHOWERS IN THE WAKE OF THE COLD FRONT. TEMPS COLD ENOUGH
THAT ANY PCPN THAT OCCURS WILL BE SNOW.
SFC HIGH BUILDS IN ONCE AGAIN BEHIND THE COLD FRONT...BRINGING YET
ANOTHER CANADIAN COLD AIRMASS...BUT DRY CONDITIONS THROUGH FRIDAY.
WIND CHILLS COULD BECOME AN ISSUE YET AGAIN...MAINLY OVER WESTERN
AREAS...WITH LOWS HOVERING RIGHT AROUND ZERO WED-THURS NIGHTS.
&&
.AVIATION /15Z SATURDAY THROUGH WEDNESDAY/...
SNOW WILL OVERSPREAD THE TERMINALS THIS MORNING FROM SOUTHWEST TO
NORTHEAST. IFR/SUB-IFR CIGS AND VSBYS ARE EXPECTED ONCE SNOW BEGINS
THROUGH THIS AFTERNOON. SNOW WILL CHANGE TO A WINTRY MIX LATE THIS
AFTERNOON AND EVENING BEFORE ENDING AS SOME RAIN TONIGHT.
HOWEVER...FREEZING RAIN MAY HANG ON FOR THE NORTHERN TERMINALS.
IFR/SUB-IFR CONDITIONS WILL CONTINUE. PRECIPITATION WILL END LATE
TONIGHT INTO SUNDAY FROM NORTHWEST TO SOUTHEAST AS DRIER AIR WORKS
ITS WAY IN ALOFT. HOWEVER...LOW CLOUDS AND AREAS OF FOG WILL REDUCE
CIGS/VSBYS THROUGH SUNDAY MORNING BEFORE CONDITIONS IMPROVE SUNDAY
AFTERNOON.
MAINLY VFR CONDITIONS THROUGH THE COMING WEEK WITH MULTIPLE PERIODS
OF HIGH PRESSURE. SUB-VFR CONDITIONS POSSIBLE WITH ANY SNOW TUES
NIGHT-WED.
NW GUSTS TO 20 KTS PSBL SUN NIGHT-MONDAY...AND THEN AGAIN WEDNESDAY
BEHIND THE FRONT.
&&
.MARINE...
A SMALL CRAFT ADVISORY IS IN EFFECT FOR THE WATERS TODAY...AND
PORTIONS OF THE MARYLAND CHESAPEAKE BAY AND LOWER TIDAL POTOMAC
RIVER TONIGHT.
A COLD FRONT WILL PASS THROUGH THE WATERS SUNDAY. WINDS WILL SHIFT
TO THE NORTHWEST...BUT SPEEDS WILL LIKELY BE BELOW SCA CRITERIA
SINCE THE PRESSURE GRADIENT WILL BE WEAK.
TIGHTENING PRESSURE GRADIENT AND CAA WILL INCREASE WINDS SUNDAY
NIGHT...WITH GUSTS 20-25 KTS. OCCASIONAL GUSTS TO 30 KTS PSBL MONDAY
MORNING...WITH LOW CONFIDENCE OF GALES BEING REACHED. THE SCA
CONDITIONS WILL CONTINUE THROUGH MONDAY...WITH WINDS GRADUALLY
DIMINISHING MONDAY NIGHT.
SUB-SCA CONDITIONS TUES-TUES NIGHT. PSBL SCA CONDITIONS RETURN
BEHIND THE NEXT COLD FRONT WED WITH GUSTS UP TO 20 KTS LASTING INTO
THURS. SUB-SCA CONDITIONS RETURN BY FRIDAY.
&&
.LWX WATCHES/WARNINGS/ADVISORIES...
DC...WINTER WEATHER ADVISORY UNTIL 6 AM EST SUNDAY FOR DCZ001.
MD...WINTER STORM WARNING UNTIL 6 AM EST SUNDAY FOR MDZ003-501-502.
WINTER WEATHER ADVISORY UNTIL 6 AM EST SUNDAY FOR MDZ013-014.
WINTER STORM WARNING UNTIL 9 AM EST SUNDAY FOR MDZ004>006-011-
503>508.
WINTER WEATHER ADVISORY UNTIL 3 AM EST SUNDAY FOR MDZ016>018.
VA...WINTER STORM WARNING UNTIL 6 AM EST SUNDAY FOR VAZ025>031-040-
501-503-504-506>508.
WINTER WEATHER ADVISORY UNTIL 6 AM EST SUNDAY FOR VAZ036>039-
050>054-502.
WINTER STORM WARNING UNTIL 9 AM EST SUNDAY FOR VAZ505.
WINTER WEATHER ADVISORY UNTIL 3 AM EST SUNDAY FOR VAZ055>057.
WV...WINTER STORM WARNING UNTIL 6 AM EST SUNDAY FOR WVZ050>053-055-
501>506.
MARINE...SMALL CRAFT ADVISORY UNTIL 6 PM EST THIS EVENING FOR ANZ532-
540.
SMALL CRAFT ADVISORY UNTIL 6 PM EST THIS EVENING FOR ANZ530-
531-535-536-538-539.
SMALL CRAFT ADVISORY UNTIL 1 AM EST SUNDAY FOR ANZ533-534-537-
541>543.
&&
$$
SYNOPSIS...BJL
NEAR TERM...BJL/HAS
SHORT TERM...BJL
LONG TERM...SEARS
AVIATION...BJL/SEARS
MARINE...BJL/SEARS/HAS
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
653 PM EST SUN FEB 22 2015
.SHORT TERM...(THIS EVENING THROUGH MONDAY)
ISSUED AT 305 PM EST SUN FEB 22 2015
A VERY COLD UPPER TROUGH IS SLIDING EAST ACROSS THE UPPER GREAT
LAKES REGION THIS AFTERNOON...WITH RAP ANALYZED 850MB TEMPS OF -29C
OVER WESTERN LAKE SUPERIOR. THIS HAS LED TO AFTERNOON TEMPERATURES
AROUND 25-30 DEGREES BELOW THE NORMAL HIGHS FOR THIS TIME OF YEAR
WITH 2PM TEMPERATURES RANGING FROM -10 AT KCMX TO 7 AT KMNM. THE
COLD AIR AND A FEW BREAKS IN THE ICE...OR AT LEAST AREAS OF THIN
ICE...HAS CONTINUED TO LEAD TO VERY THIN BANDS OF LAKE EFFECT OFF
LAKE SUPERIOR IN THE NORTHWEST WIND SNOW BELTS. WHILE THE BANDS HAVE
BEEN THIN...OBS AND WEBCAMS HAVE SHOWN THAT THEY CONTINUE TO BE
EFFICIENT AT REDUCING VISIBILITIES WITH ALL OF THE CLOUDY WELL BELOW
THE DGZ. THOSE VERY LOCALIZED LOWER VISIBILITIES HAVE ALSO BEEN
AIDED BY BLOWING SNOW FROM THE GUSTY NORTHWEST WINDS OF 15-30MPH.
MEANWHILE...A SURFACE HIGH IS CURRENTLY LOCATED OVER THE EASTERN
DAKOTAS AND AN ASSOCIATED SURFACE RIDGE IS NOSING INTO THE UPPER
GREAT LAKES.
THE HIGH WILL DROP SOUTHEAST INTO THE MID MISSISSIPPI VALLEY
TONIGHT...WHICH WILL PUSH A RIDGE ACROSS THE UPPER GREAT LAKES
REGION. THIS RIDGE WILL LEAD TO BACKING WINDS THROUGH THE
NIGHT...BECOMING SOUTHWESTERLY LATE TONIGHT OVER THE WEST AND MONDAY
MORNING OVER THE EAST. THESE BACKING WINDS...ALONG WITH INCREASING
SUBSIDENCE...WILL DIMINISH THE LAKE EFFECT POTENTIAL FROM THE
LIMITED HEATING FROM LAKE SUPERIOR. THUS...EXPECT SKIES TO BECOME
MOSTLY CLEAR THIS EVENING OVER MUCH OF THE AREA AS THE DIURNAL CU
DISSIPATE...WITH THE EASTERN U.P. HANGING ON THE LONGEST INTO THE
OVERNIGHT HOURS. WHILE THE CLEAR SKIES WILL PROMOTE RADIATIONAL
COOLING...THINKING THERE WILL BE ENOUGH MIXING FROM JUST ABOVE THE
SURFACE AND THE REMAINING PRESSURE GRADIENT TO KEEP LOWS FROM
GETTING AS COLD AS SEEN A FEW DAYS AGO ON THE CLEAR/CALM NIGHTS. BUT
WITH THE COLD AIR IN PLACE AND LITTLE REBOUND IN TEMPS TODAY...HAVE
LOWS IN THE TEENS AND TWENTIES BELOW ZERO FOR TONIGHT. WHEN COMBINED
WITH THE EXPECTED WINDS OF 4-8MPH TONIGHT...WIND CHILL VALUES WILL
REMAIN IN THE -25 TO -35 DEGREE RANGE THROUGH MONDAY MORNING. DO
HAVE A FEW AREAS WHERE WIND CHILLS WILL BE IN WARNING CRITERIA
(GENERALLY OVER IRON COUNTY)...BUT WITH WINDS IN THOSE AREAS ONLY
AROUND 5MPH OVERNIGHT...DIDN/T FEEL THAT THE WINDS WERE CLOSE ENOUGH
TO OUR 10MPH CRITERIA TO ISSUE THE WARNING. ALSO AM A LITTLE
CONCERNED WITH WIND CHILLS REACHING WARNING CRITERIA OVER THE
KEWEENAW PENINSULA...AS THEY HAVE BEEN BOUNCING BACK AND FORTH OVER
THE -35 CRITERIA LATE THIS MORNING AND INTO THE AFTERNOON. THIS WILL
LIKELY CONTINUE THROUGH MUCH OF THE NIGHT AS WINDS BACK AND THE
TIGHTEST GRADIENT PIVOTS OVER THAT AREA. EITHER WAY...IT WILL BE
VERY COLD ACROSS UPPER MICHIGAN TONIGHT INTO MONDAY MORNING.
OVERALL...MONDAY LOOKS TO BE QUIET ACROSS THE AREA AS THE HIGH
PRESSURE RIDGE DEPARTS. AFTER A SUNNY START TO THE DAY...MID-HIGH
CLOUDS WILL STREAM OVER THE AREA THROUGH THE AFTERNOON AHEAD OF A
COLD FRONT THAT WILL MOVE THROUGH THE AREA LATE MONDAY NIGHT. BUT
WITH ABUNDANT DRY AIR BETWEEN 900-700MB...EXPECT THE PRECIPITATION
TO STAY OFF TO THE WEST OF UPPER MICHIGAN THROUGH THE LATE
AFTERNOON. WINDS WILL GET GUSTY OUT OF THE SOUTHWEST DURING THE
AFTERNOON AND ESPECIALLY THE EVENING. THUS...ADDED PATCHY BLOWING
SNOW TO SOME AREAS OVER THE WEST DURING THE LATE AFTERNOON. WILL SEE
HIGHS REBOUND INTO THE SINGLE DIGITS AND A FEW LOWER TEENS ABOVE
ZERO TOMORROW...BUT WITH THE INCREASING WINDS IN THE AFTERNOON IT
WILL STILL FEEL VERY COLD.
.LONG TERM...(MONDAY NIGHT THROUGH SUNDAY)
ISSUED AT 356 PM EST SUN FEB 22 2015
PATTERN OF HIGH AMPLITUDE UPR RIDGE OVER THE ERN PACIFIC/WRN
NAMERICA AND DEEP TROF OVER CENTRAL AND ERN NAMERICA WL PERSIST THRU
MUCH OF THE WEEK...RESULTING IN A CONTINUED NW FLOW ALOFT THAT WL
BRING ARCTIC SURGES INTO THE UPPER LKS THRU MID WEEK. TOWARD THE END
OF THE WEEK THOUGH...FALLING HGTS OVER THE W WL ALLOW FOR A MORE
ZONAL FLOW AND SOME AIRMASS MODERATION. BUT WITH DRY HI PRES FCST TO
BE DOMINATING...LOW TEMPS MAY STILL BE QUITE COLD DESPITE THE MORE
SEASONABLE H85 AND DAYTIME TEMPS.
MON NGT/TUE...SHRTWV AND ACCOMPANYING SFC LOW DESCENDING SE INTO FAR
NW ONTARIO BY MON EVNG ARE FCST TO SLIDE JUST NE OF LK SUP DURING
THIS TIME...WITH ATTENDANT COLD FROPA MOVING OVER UPR MI LATE MON
NIGHT AND TUE MRNG. SOME LIGHT SN IN THE WAA/ISENTROPIC ASCENT
PATTERN AHEAD OF THIS DISTURBANCE WL OVERSPREAD UPR MI FM THE NW ON
MON NGT AND PERSIST INTO TUE MRNG BEFORE THE COLD FROPA. SINCE THE
MSTR INFLOW WL BE RATHER UNIMPRESSIVE...WITH MIXING RATIOS OF 1-1.5
G/KG FCST ON 280K ISENTROPIC SFC...AND VERY DRY ANTECEDENT AIRMASS
IN PLACE WHICH WL TAKE TIME TO MOISTEN...ACCOMPANYING SN ACCUMS
SHOULD BE LIMITED TO NO MORE THAN 1 TO 2 INCHES FOR MOST OF CWA WITH
MAYBE A FEW LOCATIONS SEEING 3-4 INCHES FAR EAST AND OVER TIP OF
KEWEENAW...WHERE HIGHER POPS/QPF WL BE MAINTAINED CLOSER TO THE
SHRTWV TRACK...LONGER DURATION OF ISENTROPIC ASCENT AND AREA OF
STRONGER DEEP LAYER Q-VECT CONV. ALTHOUGH MODELS SNDGS INDICATE THE
DGZ TO BE RATHER DEEP AND INTERSECTING MUCH OF THE ASSOCIATED
UVV...STRONG WINDS THROUGH THE MUCH OF THE LAYER MIGHT BREAK UP THE
DENDRITES TO A CERTAIN EXTENT. BUT AT SAME TIME...THE SMALLER FLAKES
WOULD BE MORE EFFICIENT AT RESTRICTING VSBY WHILE BEING BLOWN ABOUT
BY THE GUSTY VEERING WINDS OCCURRING UNDER THE TIGHT PRES GRADIENT
AHEAD OF THE COLD FRONT. WITH H85 THERMAL RDG OVER UPR MI ON MON NGT
AND THE GUSTY WINDS...EXPECT RELATIVELY HIGH MIN TEMPS. WSHFT TO THE
NW FOLLOWING THE TUE MORNING COLD FROPA WL DRAG ANOTHER ARCTIC
AIRMASS BACK INTO THE CWA IN THE AFTN...DROPPING H85 TEMPS TO -20C
OR COLDER AGAIN BY 00Z WED AND ALLOWING FOR AT LEAST SCATTERED LES
TO DEVELOP IN WHATEVER BREAKS THERE ARE IN LAKE SUPERIOR ICE COVER.
TUE NGT INTO WED NIGHT...MEDIUM RANGE GUIDANCE FCSTS H85 TEMPS TO
FALL AS LO AS -28C TO -30C AROUND 12Z WED IN COLD NNW FLOW AHEAD OF
THE NEXT CANADIAN HIGH PRES BUILDING TOWARD THE NRN PLAINS. THERE
MAY BE SOME LES OFF BREAKS IN THE EXTENSIVE ICE COVER...BUT THE
BIGGEST STORY WL BE WIND CHILLS AT LEAST REACHING INTO ADVY CRITERIA
TUE NIGHT INTO WED MORNING AS 950 MB WINDS ARE FCST AOA 30 KTS
DURING THE DESTABILIZING PERIOD OF CAA THAT WL DROP MIN TEMPS BLO
ZERO AGAIN. AFTER HIGHS POSSIBLY STRUGGLING TO REACH ABV ZERO OVER
THE NW CWA ON WED...ANOTHER BITTER COLD NIGHT IS IN STORE FOR WED
NIGHT WITH DOUBLE DIGIT BLO ZERO READINGS LIKELY OVER A GOOD
PORTION OF THE CWA.
THU INTO SUN...THE ARCTIC HI OVER SCENTRAL CANADA ON WED IS FCST TO
DRIFT SLOWLY TO THE ESE REACHING THE NRN PLAINS ON THU...AND THE MID
MS VALLEY AND LOWER GREAT LAKES/OH RIVER VALLEY ON FRI BEFORE
REACHING THE MID-ATLANTIC STATES ON SAT UNDER A PATTERN OF SLOWLY
RISING 5H HGTS IN THE GREAT LAKES DOWNSTREAM OF TROFFING OVER WRN
NAMERICA. THE RESULT WL BE A PERIOD OF MAINLY DRY WX UNDER DOMINANT
SFC HIGH PRES RIDGE. ALTHOUGH THERE MAY BE SOME LES MAINLY E OF
MARQUETTE INTO THU WHILE THE LLVL FLOW IS STILL NW...BACKING WINDS
TOWARD THE W AND THEN SW WL SHIFT ANY REMAINING LES OUT INTO LK SUP
BY LATE THU NIGHT. H85 TEMPS ARE FCST TO MODERATE TO -15C TO -17C BY
FRI/SAT...ALLOWING DAYTIME TEMPS TO WARM NEAR 20F UNDER A GOOD DEAL
OF SUNSHINE. HOWEVER...STILL EXPECT VERY COLD OVERNIGHT TEMPS (BLO
ZERO) AT LEAST THU NIGHT AND FRI NIGHT AS FCST PWAT IS LOWER THAN
.10 INCH UNDER LIGHT WINDS. MORE CLDS AND LIGHT MAY ARRIVE SAT NIGHT
INTO SUN IN ADVANCE OF THE NEXT APPROACHING LOW PRES TROF.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z MONDAY EVENING)
ISSUED AT 652 PM EST SUN FEB 22 2015
A STEADY WNW SLOWLY BACKING SW FLOW OF DRY AIR TO THE N OF HI PRES
MOVING INTO THE OH RIVER VALLEY WL RESULT IN VFR CONDITIONS AT ALL 3
TAF SITES THIS FCST PERIOD. ALTHOUGH THE W WIND WL UPSLOPE INTO CMX
THRU THIS EVNG...THE UPSTREAM AIRMASS IS SO DRY AND LK SUP
SUFFICIENTLY ICE COVERED TO PREVENT ANY LES OR EVEN MUCH IN THE WAY
OF CLDS. THE SW WINDS WL STRENGTHEN AND TURN GUSTY ON MON AFTN AS
THE PRES GRADIENT TIGHTENS AHEAD OF A COLD FNT APRCHG FM THE NW.
&&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 305 PM EST SUN FEB 22 2015
HIGH PRESSURE IN THE DAKOTAS WILL MOVES INTO THE MID MISSISSIPPI
VALLEY LATE TONIGHT AND MONDAY MORNING...WHILE SHIFTING A RIDGE
ACROSS THE UPPER GREAT LAKES REGION. THIS WILL LEAD TO WEAKENING
WINDS TONIGHT...BEFORE QUICKLY INCREASING OUT OF THE SOUTHWEST ON
MONDAY AFTERNOON AHEAD OF A LOW PRESSURE SYSTEM DROPPING SOUTHEAST
THROUGH NORTHERN ONTARIO. THIS WILL LEAD TO SOUTHWESTERLY GALES OF
35-40KTS OVER PORTIONS OF LAKE SUPERIOR MONDAY AFTERNOON/EVENING
AND HAVE ISSUED A GALE WARNING FOR MUCH OF WESTERN/CENTRAL LAKE
SUPERIOR FOR LATE MONDAY AFTERNOON AND MONDAY NIGHT. THEN AS A COLD
FRONT SLIDES SOUTHEAST ACROSS LAKE SUPERIOR LATE MONDAY NIGHT INTO
TUESDAY MORNING AND SHIFT WINDS TO THE NORTHWEST. THERE MAY BE A FEW
GALE FORCE GUSTS TO 35 KNOTS BEHIND THE FRONT ON TUESDAY OVER
EASTERN LAKE SUPERIOR. A HIGH PRESSURE RIDGE WILL BUILD BACK INTO
THE AREA WEDNESDAY AND REMAIN INTO FRIDAY...LEADING TO GENERALLY
LIGHT WINDS BELOW 20KTS.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
WIND CHILL ADVISORY UNTIL NOON EST /11 AM CST/ MONDAY FOR
MIZ001>007-009>011-013-014-084-085.
WIND CHILL ADVISORY UNTIL 11 AM CST MONDAY FOR MIZ012.
LAKE SUPERIOR...
GALE WARNING FROM 7 PM MONDAY TO 7 AM EST TUESDAY FOR LSZ266.
GALE WARNING FROM 4 PM EST /3 PM CST/ MONDAY TO 7 AM EST /6 AM
CST/ TUESDAY FOR LSZ162-263-264.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...SRF
LONG TERM...VOSS
AVIATION...KC
MARINE...SRF
AREA FORECAST DISCUSSION
NWS GRAND RAPIDS MI
1224 AM EST SAT FEB 21 2015
LATEST UPDATE...
AVIATION
.SYNOPSIS...
ISSUED AT 333 PM EST FRI FEB 20 2015
AN APPROACHING ARCTIC COLD FRONT WILL SPREAD MOSTLY LIGHT SNOW
ACROSS THE AREA THIS AFTERNOON AND TONIGHT. LOCALIZED HEAVIER SNOW
IS EXPECTED AT THE LAKESHORE NORTH OF THE MUSKEGON AREA. THE SNOW
WILL LINGER SATURDAY AS ANOTHER LOW MOVES NORTHEAST ACROSS THE OHIO
VALLEY. LOCATIONS AROUND AND SOUTH OF I-94 COULD SEE UP TO A COUPLE
INCHES OF ADDITIONAL SNOW SATURDAY. ANOTHER CLIPPER LOW COULD BRING
SNOWY AND WINDY CONDITIONS ACROSS THE AREA TUESDAY COULD IMPACT
TRAVEL. OTHERWISE...LAKE EFFECT SNOW SHOWERS WILL BE VERY COMMON
THROUGH THE COMING WEEK.
THERE WILL BE A VERY BRIEF WARMUP WITH HIGH TEMPERATURES APPROACHING
30 ON SATURDAY. THEN COLD RETURNS IN FORCE SATURDAY NIGHT WITH HIGHS
GENERALLY IN THE TEENS AND LOWS IN THE SINGLE DIGITS OR BELOW ZERO
FOR THE REST OF THE COMING WORK WEEK.
&&
.UPDATE...
ISSUED AT 915 PM EST FRI FEB 20 2015
WE`LL KEEP THE HEADLINE AS IS. IF WE`RE GOING TO GET ACCUMULATING
SNOW...IT WILL BE ROUGHLY NOW THROUGH 09Z. WINDS ARE GRADUALLY
BECOMING SOUTHWESTERLY AND WILL HELP TO PUSH THE LAKE COVERGENT
BAND INLAND. LUDINGTON IS AT 1SM SN CURRENTLY AND UPSTREAM ECHOS
SUGGEST VSBYS COULD FALL BELOW 1SM.
&&
.SHORT TERM...(THIS EVENING THROUGH SUNDAY NIGHT)
ISSUED AT 333 PM EST FRI FEB 20 2015
INCREASED FORECAST SNOW AMOUNTS TONIGHT ALONG THE LAKESHORE NORTH OF
WHITEHALL AND HOISTED AN ADVISORY. LUDINGTON VISIBILITIES ALREADY
HAVE BEEN AT OR BELOW HALF A MILE IN SNOW AND WE EXPECT THAT AREA
COULD EASILY SEE 5 INCHES OR MORE TOTAL ACCUMULATIONS OVERNIGHT.
CURRENT SURFACE OBSERVATIONS SHOW A SIGNIFICANT OFFSHORE COMPONENT
TO THE WINDS OVER OUR NORTHERN LAKESHORE AREA. HRRR GUIDANCE
INDICATES A STRENGTHENING CONVERGENCE ZONE PARALLEL TO AND BARELY
OFF THE LAKESHORE EARLY TONIGHT THAT SHOULD FOCUS BRIEFLY INTENSE
SNOWFALL RATES. THIS CONVERGENCE AREA AND ASSOCIATED SNOWFALL
SHOULD PUSH INLAND BY AROUND MIDNIGHT. ALTHOUGH THE ADVISORY IS
SET TO EXPIRE AT 7 AM SATURDAY...COULD EASILY SEE SNOWFALL RATES
DECREASING SIGNIFICANTLY AFTER MIDNIGHT.
WITH THIS UPPER TROUGH IS A DEVELOPING SURFACE LOW THAT TRACKS
NORTHEAST ACROSS THE OHIO VALLEY. WE ARE FAIRLY CERTAIN THAT IMPACTS
WITH THIS SHOULD BE MINIMAL WITH PERHAPS A COUPLE INCHES
ACCUMULATION NEAR JACKSON DURING THE DAY SATURDAY.
SATURDAY NIGHT AND SUNDAY SHOULD SEE PERSISTENT LAKE EFFECT WITH 850
MB TEMPERATURES DROPPING TOWARDS -25C. LIMITED MOISTURE AND
SUB-OPTIMAL MICROPHYSICS SHOULD LIMIT ADDITIONAL ACCUMULATIONS TO
AROUND A COUPLE INCHES NEAR THE LAKESHORE.
.LONG TERM...(MONDAY THROUGH FRIDAY)
ISSUED AT 333 PM EST FRI FEB 20 2015
NO SIGNIFICANT CHANGES TO LONG TERM FORECAST...STRONG CLIPPER COULD
BRING 35MPH+ WIND GUSTS ON TUESDAY WITH SNOW SQUALLS TUESDAY
NIGHT INTO WEDNESDAY. ANOTHER ARCTIC AIRMASS WILL KEEP TEMPERATURES
WELL BELOW NORMAL FOR THE END OF THE WEEK.
LATEST 12Z GUIDANCE REMAINS IN VERY GOOD AGREEMENT ON EVOLUTION OF
WEATHER PATTERN OVER THE NEXT WEEK. BASICALLY A CONTINUATION OF THE
CURRENT WEATHER WITH THE ANOMALOUS WEST COAST RIDGE AND DOWN STREAM
TROUGH CENTERED OVER GREAT LAKES. THERE IS HOWEVER SOME CHANCE OF A
TEMPORARY BREAKDOWN OF THIS PATTERN NEXT WEEKEND WHICH WOULD LEAD TO
NEAR NORMAL TEMPERATURES FOR THE END OF FEBRUARY.
OUR EVENTUAL MID-WEEK CLIPPER IS PRESENTLY NORTH OF BARROW...ALASKA.
IT IS FORECAST TO DIG SOUTHEASTWARD THROUGH WESTERN CANADA REACHING
THE UPPER GREAT LAKES ON TUESDAY WITH AN ALMOST CLOSED H500 LOW BY
WEDNESDAY. ALONG WITH IT COMES A SHOT OF SIBERIAN ARCTIC AIR.
THIS WOULD NORMALLY BE A GOOD SETUP FOR A SIGNIFICANT LAKE
ENHANCED EVENT...BUT HAVE A COUPLE OF CONCERNS. THE FIRST IS THE
THAT THE WAVE IS PRESENTLY IN A DATA SPARSE AREA OBSERVATION
WISE...SO WHILE THE TREND HAS BEEN STABLE AT PRESENT...WOULD NOT
BE SURPRISED BY A JUMP OR TWO IN THE FORECAST OVER THE NEXT COUPLE
OF DAYS. SECONDLY...LAKE MICHIGAN IS REALLY STARTING TO SLUSH UP
AND THAT WILL BEGIN TO LIMIT THE ABILITY OF THE LAKE TO ENHANCE
THE SYSTEM SNOWFALL. STAY TUNED...
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SATURDAY NIGHT)
ISSUED AT 1223 AM EST SAT FEB 21 2015
MVFR CONDITIONS LOOK TO BE THE PREDOMINANT CATEGORY THE NEXT 24
HOURS...THROUGH 06Z SATURDAY NIGHT. THE MVFR CONDITIONS WILL
MAINLY BE FROM CEILINGS IN THE 1000-3000FT RANGE THAT ARE FORECAST
TO REMAIN IN PLACE. AN AREA OF LIGHT SNOW IS ALREADY EXITING THE
AREA INTO EASTERN LOWER MICHIGAN AT 05Z...WITH SOME LIGHT SNOW
LEFT OVER STILL NEAR THE LAKE MICHIGAN SHORE. THIS TOO SHOULD
GRADUALLY WIND DOWN OVERNIGHT. KMKG HAS NOT BEEN IMPACTED MUCH AND
NOT EXPECTING MUCH GOING FORWARD EITHER.
ONLY REAL SNOW POTENTIAL...AND ITS VERY LOW CONFIDENCE/LOW
POTENTIAL...IS DURING THE DAY ON SATURDAY. THE NORTHERN FRINGES
OF THE PRECIPITATION SHIELD BRUSH THE AREA FROM THE OHIO VALLEY
SYSTEM. HAVE LIGHT SNOW IN AT KBTL AND KJXN BUT NOT EXPECTING MUCH
AT ALL. MOST MODELS HAVE THE SNOW MISSING THE AREA COMPLETELY.
&&
.HYDROLOGY...
ISSUED AT 308 PM EST FRI FEB 20 2015
FAIRLY STEADY RIVER LEVELS ARE EXPECTED ACROSS THE AREA... WITH NO
SITES NEAR BANKFULL. TEMPERATURES WILL ONLY APPROACH FREEZING ON
SATURDAY WITH VALUES BELOW 20 DEGREES MOST OF THE WEEK. THIS SHOULD
RESULT IN THE ICE ON AREA RIVERS AND THE WATER IN THE SNOWPACK
REMAINING LOCKED UP. CURRENTLY... THERE ARE NO SUSPECTED ICE JAMS IN
THE AREA. SERIOUS ICE JAMS AND FLOODING CONCERNS ARE UNLIKELY UNTIL
A SIGNIFICANT WARM UP AND RAINFALL OCCUR.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...WINTER WEATHER ADVISORY UNTIL 7 AM EST THIS MORNING FOR MIZ037-
043-050.
LM...NONE.
&&
$$
UPDATE...04
SYNOPSIS...TJT
SHORT TERM...TJT
LONG TERM...COBB
AVIATION...DUKE
HYDROLOGY...63
AREA FORECAST DISCUSSION
NWS GAYLORD MI
1200 AM EST SAT FEB 21 2015
.UPDATE...
ISSUED AT 901 PM EST FRI FEB 20 2015
MOTHER NATURE HAD A FEW SURPRISES FOR US THIS EVENING. LAKE MI
CONVERGENCE BAND SET UP WELL OFFSHORE OF MANISTEE/BENZIE
COUNTIES...ONLY SLOWLY DRIFTING EAST. MBL AWOS HAS STRUGGLED TO
REPORT ANY CLOUDS AT ALL...AND PRECIP THERE HAS BEEN MINIMAL. THE
BAND TO THE WEST WILL ARRIVE IN THOSE AREAS TOWARD MIDNIGHT...BUT
ONLY AS SYNOPTIC SUPPORT IS EXITING. BRIEF HEAVIER SNOW SHOWERS
WILL RESULT...BUT WILL BE HARD TO GET MORE THAN 2 INCHES OR SO. SO
THE ADVISORY HAS BEEN CANCELLED THERE.
THIS BAND IS EDGING INTO FAR WESTERN MACKINAC CO. SOME REPORTS OF
NEARLY 6 INCHES OF FLUFF WITH THIS ONE...A BIT NE OF ISQ IN
SCHOOLCRAFT CO. HAVE BUMPED UP ACCUMS IN WESTERN MACK...BUT ONLY
TO AROUND 3 INCHES...AS THE BANDS EASTWARD DRIFT IS INCREASING.
N CENTRAL LOWER IS THE OTHER BULLSEYE...WITH A SMALL AREA OF 30DBZ
RETURNS THAT STUCK BETWEEN THE OFFICE AND BELLAIRE FOR A BIT. THIS
HAS STARTED TO WEAKEN AND PULL OUT TO THE ESE...BUT NOT BEFORE A
QUICK BURST OF 2-3 INCHES. THIS AREA OF ENHANCED SNOW IS
SOMEWHAT...INEXPLICABLE (CAN/T BLAME THE LAKES FOR THIS ONE)...
BUT AS LONG AS IT DOESN/T REFORM IN THE SAME SPOT WE WILL MANAGE
TO AVOID THE NEED FOR AN ADVISORY. STILL...HAVE BUMPED UP SNOWFALL
TOTAL ACCUMS NEAR/E OF US-131 AND SOUTH OF M-32.
&&
.NEAR TERM...(THIS EVENING THROUGH TONIGHT)
ISSUED AT 406 PM EST FRI FEB 20 2015
...WIDESPREAD GENERALLY LIGHT SNOW TONIGHT...
HIGH IMPACT WEATHER POTENTIAL: NARROW CORRIDOR OF HEAVIER SNOW
POSSIBLE WEST OF US-31 IN MANISTEE AND BENZIE COUNTIES AND OVER
PARTS OF FAR WESTERN MACKINAC COUNTY...OTHERWISE GENERALLY LIGHT
SNOW ACCUMULATIONS OVER THE REMAINDER OF THE AREA.
PRIMARY FORECAST CHALLENGES/CONCERNS: HOW FAR INLAND WILL ENHANCED
HEAVIER SNOW BAND OVER LAKE MICHIGAN GET INTO COASTAL AREAS.
DETAILS: ISENTROPIC UPGLIDE /285-270K SFC/ INCREASING ACROSS
NORTHERN MICHIGAN IN ADVANCE OF SHORTWAVE TROF OVER MN/NRN WI. TOP
DOWN SATURATION GRADUALLY YIELDING LIGHT SNOW OVER FAR WESTERN
PORTIONS OF THE AREA. LIGHT SNOW WILL OVERSPREAD THE ENTIRE AREA BY
EARLY THIS EVENING...WITH A 6 HOUR WINDOW OF FAVORABLE DYNAMICS
/ALBEIT SOMEWHAT LIMITED MOISTURE/. NOT THE MOST FAVORABLE CLOUD
MICROPHYSICS WITH BEST OMEGA NOT SQUARELY FOCUSED WITHIN THE DGZ FOR
MUCH OF THE SNOWFALL PERIOD. TRANSITORY NATURE OF THE SHORTWAVE
COMBINED WITH MID LEVEL MIXING RATIO/S ON THE ORDER OF 1-2 G/KG
POINT TOWARD A GENERAL 1-2 INCH SNOWFALL FOR MOST LOCATIONS.
THE EXCEPTION TO THIS IS OVER PARTS OF MANISTEE...BENZIE AND
MACKINAC COUNTIES...WHERE NORTH-SOUTH ORIENTED CONVERGENCE AREA
UP THE SPINE OF LAKE MICHIGAN WILL CREATE POCKETS OF HEAVIER SNOW.
HIGH RESOLUTION HRRR GUIDANCE SHOWS THIS ENHANCED LAKE MICHIGAN BAND
QUITE WELL...KEEPING IT NEAR/ALONG THE LAKE MICHIGAN COAST THIS
EVENING...POSSIBLY NOSING IT INTO FAR WESTERN MACKINAC COUNTY.
AFTER COLLABORATION WITH THE GRAND RAPIDS NWS OFFICE AND WITH THE
POTENTIAL FOR SOME LOCALIZED 3-5 INCH SNOWFALL AMOUNTS IN THE
WESTERN PARTS OF BENZIE-MANISTEE COUNTIES...WENT AHEAD AND ISSUED A
WINTER WEATHER ADVISORY THROUGH 7 AM SATURDAY. NO ADVISORY FOR
MACKINAC COUNTY...AS BEST CONVERGENCE REMAINS SOUTH OF THAT AREA AND
ENHANCED SNOWFALL POTENTIAL WOULD LIKELY ONLY IMPACT A SMALL PORTION
OF THE COUNTY /FAR WESTERN AREAS/.
WIDESPREAD SNOW ENDS FROM WEST-EAST AFTER MIDNIGHT AS THE SHORTWAVE
PULLS EAST AND BEST DYNAMICS DIMINISH. A MUCH "WARMER" NIGHT IN
STORE FOR THE AREA COMPARED TO LAST NIGHT /WHICH ISN`T EXACTLY
SAYING MUCH/ WITH LOW TEMPERATURES GENERALLY IN THE SINGLE DIGITS
ABOVE ZERO.
&&
.SHORT TERM...(SATURDAY THROUGH MONDAY)
ISSUED AT 406 PM EST FRI FEB 20 2015
HIGH IMPACT WEATHER POTENTIAL: ANOTHER COLD WAVE SUNDAY
NIGHT/MONDAY MORNING, BUT NOT AS COLD AS THIS MORNING.
FORECAST CHALLENGES: LES IMPACTS WITH MOST OF THE GREAT LAKES
COVERED AND LOW TEMPERATURES AS THE NEXT COLD WAVE MOVE INTO THE
UPPER GREAT LAKES SUNDAY/MONDAY.
(2/21)SATURDAY...AROUND 12Z, THE COLD FRONT BEGINS TO MOVE THROUGH
THE REGION. THE SOUTHWEST WINDS SHOULD BE TURNING WEST BY 12Z,
LEADING TO A SHORT PERIOD OF WESTERLY FETCH FOR THE LAKE SNOW. THE
ONLY ISSUE WITH ANY LES IS THE N LAKE MICHIGAN HAS LITTLE OPEN
WATER, AND MOST OF THE THAT IS SOUTH OF THE MANITOU ISLANDS. WIND
DIRECTIONS GIVE LIMITED FETCH AS THEY GET INTO N LOWER, AND EVEN E
UPPER. SO HAVE SCALED BACK THE POPS A BIT AS THE OVERALL AREA WILL
HAVE A LIGHT CLIPPER SNOW, WITH LITTLE ADDED LES ON THE BACK END.
WINDS AFTER 18Z BECOME MORE NW AND NNW SO MAY GET SOME MINOR SNOW
AND FLURRIES NORTH OF M-32 AS THE STREAM LINES POINT TO LITTLE TO
NOTHING HAPPENING AS THE ATMOSPHERE DRIES OUT AS WELL BY THE EARLY
EVENING.
SATURDAY NIGHT...THE 850-700 MB LAYER RH FALL TO AROUND 40% BY 00Z
AND WITH THE 850 MB TEMPERATURES OF -20C (AT 0Z)CROSSING THE ICE,
THE LES WILL BE ALMOST NON-EXISTENT THROUGH MOST OF THE NIGHT. 850
MB TEMPERATURES CONTINUE TO COOL TO AROUND -30C IN LAKE SUPERIOR,
PROVIDING SOME INSTABILITY, WITH THE MOISTURE AT 850-700 MB LAYER
INCREASING TO AROUND 80% SOME LES WOULD BE POSSIBLE, BUT LACK OF
OPEN WATER WILL BE DIFFICULT TO GET MUCH GOING.
(2/22)SUNDAY...THE AIR MASS LOOKS COLD OVERNIGHT INTO SUNDAY
MORNING, BUT THE MAIN PROBLEM IS THAT CLOUDS ARE EXPECTED TO MOVE
INTO THE REGION BY 12Z, WHICH WILL PROBABLY INHIBIT THE TEMPERATURES
FROM FALLING MUCH BELOW -20F. HOWEVER, CONSIDERING THE MODELS`
ABILITY TO GET THE CLOUDS RIGHT, WOULD NOT BE SURPRISED IF THE LOW
TEMPERATURES IN THE MORNING WILL BE COLDER THAN WE HAVE. THINK THAT
THE LOWER TEENS BELOW ZERO IDEA IS THE BEST IDEA FOR NOW, UNTIL THE
LIGHT SNOW GETS STARTED BY 18Z, MAYBE SOONER IF THE CLOUDS ENCROACH
AND THE INSTABILITY CAN GET ENOUGH MOISTURE TO PRODUCE SNOW. MINOR
SNOW ACCUMULATIONS ARE EXPECTED TO THROUGH 00Z. THE FLOW AND
MOISTURE IS EXPECTED TO CONTINUE OVERNIGHT.
(2/23)MONDAY...THE MORNING MAY TURN OUT DRY, BUT FOR NOW WILL
CONTINUE THE LIGHT SNOW CHANCE, AS THE EXTREME COLD AIR AND
RETREATING MOISTURE MAY PRODUCE MINOR ACCUMULATIONS. BY 18Z, THE
WINDS TURN WSW, SO THAT THERE COULD BE SOME LES IN THE EVENING JUST
BEFORE THE NEXT SYSTEM MOVES INTO THE UPPER GREAT LAKES.
&&
.LONG TERM...(MONDAY NIGHT THROUGH FRIDAY)
ISSUED AT 406 PM EST FRI FEB 20 2015
CONTINUED COLD WITH PERIODS OF SNOW. A COLD FRONT ASSOCIATED WITH A
LOW PRESSURE SYSTEM NEAR JAMES BAY WILL EXTEND THROUGH
MICHIGAN...POSSIBLY PRODUCING SOME ACCUMULATING SNOWS THROUGHOUT THE
BEGINNING OF THE PERIOD AND MODERATING TEMPERATURES INTO THE 20S ON
SOUTHERLY WINDS AHEAD OF THIS COLD FRONT. A LARGE AREA OF HIGH
PRESSURE WILL BUILD IN BEHIND THIS DEPARTING SYSTEM AND DOMINATE
THROUGH THE REMAINING PERIOD...CONTINUING THE COLD TEMPERATURES
WHICH ARE FAR BELOW NORMAL FOR THIS TIME OF THE YEAR. WITH THE
ABNORMALLY COLD TEMPERATURES WILL ALSO COME THE CHANCES OF NUISANCE
LAKE CLOUDS AND SOME LAKE EFFECT SNOW SHOWERS WHERE OPEN WATERS
STILL REMAIN OVER PORTIONS OF LAKE MICHIGAN AND LAKE SUPERIOR.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SATURDAY NIGHT)
ISSUED AT 1200 PM EST FRI FEB 20 2015
REMAINING SYNOPTIC SNOW WILL GRADUALLY EXIT EASTWARD OUT OF NRN
LWR MICHIGAN OVERNIGHT. HOWEVER...THIS SNOW WILL BE REPLACED WITH
SCT/NMRS LAKE EFFECT SNOW SHOWERS AS LOW LEVEL WINDS SHIFT FROM
THE SW TO THE WEST AND EVENTUALLY NW BY LATE SATURDAY AFTERNOON
BEHIND ANOTHER WAVE RIDING THRU THE FAST 500 MB FLOW. THIS SECOND
WAVE WILL ALSO PROVIDE SOME ENHANCED SYNOPTIC LIFT/MOISTURE TO
ONGOING LAKE EFFECT SNOW SHOWERS SATURDAY AFTERNOON AND EVENING.
OVERALL CONDITIONS WITHIN ANY SNOW WILL BE MAINLY MVFR...WITH
CONDITIONS POSSIBLY LOWERING TO IFR WITHIN HEAVIER SNOW SHOWERS.
SOUTHERLY SURFACE WINDS AROUND 10 KTS OVERNIGHT INTO SATURDAY WILL
SHIFT TO THE NW UNDER 10 KTS BY LATE SATURDAY AFTERNOON.
&&
.APX WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LH...NONE.
LM...NONE.
LS...NONE.
&&
$$
UPDATE...JAZ
NEAR TERM...KEYSOR
SHORT TERM...JSL
LONG TERM...TJL
AVIATION...MLR
AREA FORECAST DISCUSSION
NWS BUFFALO NY
138 PM EST SAT FEB 21 2015
.SYNOPSIS...
AN ELONGATED AREA OF LOW PRESSURE WILL CROSS THE GREAT LAKES
BRINGING WIDESPREAD...MAINLY LIGHT...SNOWFALL TO THE REGION
THROUGH THIS EVENING. AREAS OF FREEZING DRIZZLE WILL BE POSSIBLE
IN THE WAKE OF THE SYSTEM LATER TONIGHT INTO SUNDAY BEFORE
TEMPERATURES PLUNGE SUNDAY NIGHT AS ANOTHER ARCTIC FRONT SWEEPS
ACROSS THE GREAT LAKES...BRINGING POTENTIALLY RECORD BREAKING COLD
ALONG WITH LAKE EFFECT SNOW SHOWERS BY MONDAY. WHILE MONDAY WILL
BE THE COLDEST DAY OF THE PERIOD...TEMPERATURES ARE EXPECTED TO
REMAIN BELOW AVERAGE THROUGH NEXT WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
AT 100 PM...RADAR SHOWS SNOW HAS OVERSPREAD THE REMAINDER OF THE
REGION WITH THE STEADIEST SNOW BETWEEN ROCHESTER AND WATERTOWN.
THIS IS PROBABLY ASSOCIATED WITH A SLUG OF WARM AIR ADVECTION
WITH A SOUTHERLY 40 KT 925MB FLOW. THIS WILL CONTINUE TO LIFT NE
THROUGH THIS AFTERNOON. BEHIND THIS...IS A LULL IN THE
ACTION...WITH RADAR SHOWING ONLY LIGHT RETURNS. THIS LULL WILL
ONLY LAST A COUPLE HOURS...WITH RADAR SHOWING A LINE OF STEADIER
SNOW BEHIND THIS...EXTENDING FROM LAKE ERIE TO WESTERN LAKE
ONTARIO. THE SOUTHWESTERLY MID-UPPER LEVEL FLOW WILL PUSH THIS
AREA EAST ACROSS WESTERN NEW YORK LATE AFTERNOON AND INTO THIS
EVENING. THIS WILL RESULT IN ANOTHER BURST OF SNOWFALL DURING THIS
TIME. LATEST RUNS OF THE HRRR CAPTURE THIS WELL...WITH OTHER
HIGH RESOLUTION GUIDANCE HINTING AT THIS BREAK TO A LESSER EXTENT.
THERE ARE ALSO SOME MESOSCALE FEATURES IN PLAY. DOWNSLOPING HAS
LIMITED SNOWFALL RATES IMMEDIATELY NE OF THE CHAUTAUQUA
RIDGE...WITH A ENHANCED SNOWFALL RATES ACROSS THE NIAGARA FRONTIER
NEAR LAKE ONTARIO. SINCE...THE STRONGER SOUTHERLY FLOW HAS SHIFTED
EAST WITH THIS EXPECTED TO HAVE LITTLE IMPACT FOR THE REMAINDER OF
THE AFTERNOON HOURS. HOWEVER...AS THE SOUTHERLY FLOW INCREASES
ACROSS EASTERN PORTIONS OF THE CWA...MOST HIGH RESOLUTION GUIDANCE
SHOWS SIGNIFICANT UPSLOPING ON THE SOUTH FACE OF THE TUG HILL.
WHILE THIS IS SOMETIMES OVERDONE...IT APPEARS REASONABLE THIS TIME
WITH A SATURATED BOUNDARY LAYER AND RADAR CURRENTLY SHOWING THIS
ENHANCEMENT. THESE MESOSCALE FEATURES WILL HAVE AN IMPACT ON SNOW
AMOUNTS. IN THE ADVISORY AREA...EXPECT MOST AREAS TO GET 2 TO 4
INCHES OF SNOW...WITH 1 TO 3 INCHES ACROSS THE GENESEE VALLEY.
LOCALIZED AMOUNTS OF A BIT MORE ARE LIKELY IN NIAGARA COUNTY. THE
GREATEST AMOUNTS WILL PROBABLY BE IN OSWEGO AND SOUTHERN LEWIS
COUNTIES WHERE 4 TO 7 INCHES OF SNOW IS EXPECTED.
SNOW WILL TAPER OFF FROM WEST TO EAST AS THE UPPER LEVEL JET AND
DEEPER MOISTURE TRANSLATES TO THE EAST COAST. EVEN AS THE DEEPER
MID-LEVEL MOISTURE IS STRIPPED OUT...WEAK ASCENT DUE TO
APPROACHING MID/UPPER LEVEL TROUGHING ALONG WITH WESTERLY UPSLOPE
FLOW MAY RESULT IN A TRANSITION FROM LINGERING SNOW SHOWERS TO
AREAS OF FREEZING DRIZZLE LATER ON TONIGHT...PARTICULARLY ACROSS
UPSLOPE AREAS OF WESTERN NEW YORK AND EVENTUALLY THE NORTH
COUNTRY. IN ADDITION TO THE SNOW...A WINTER WEATHER ADVISORY IS IN
PLACE FOR THIS POTENTIAL. FORECAST CONFIDENCE IN FREEZING DRIZZLE
IS MARGINAL...WITH FORECAST SOUNDINGS SUPPORTING FREEZING DRIZZLE
IF PRECIPITATION OCCURS...BUT STILL SOME UNCERTAINTY IF THE FLOW
WILL BE STRONG ENOUGH TO GENERATE ANY PRECIPITATION.
TEMPERATURES WILL RISE INTO THE 20S TODAY...WHICH WILL PROBABLY
FEEL QUITE WARM TO MANY GIVEN THE COLD WEATHER OF LATE. EVEN AS
THE ELONGATED TROUGH PASSES TO OUR EAST TONIGHT...THERE WILL BE
ONLY MODEST COLD AIR ADVECTION WITH OVERNIGHT LOWS IN THE TEENS.
&&
.SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/...
SUNDAY WILL START OFF WITH WITH BROAD CYCLONIC FLOW ALOFT AND A COLD
AIR ADVECTION REGIME BEHIND THE DEPARTING SURFACE LOW. FORECAST
SOUNDINGS INDICATE THAT MID-LEVEL DRY AIR WILL BE IN PLACE ACROSS
WESTERN AND CENTRAL NEW YORK...WITH PLENTIFUL LOW-LEVEL MOISTURE IN
THE WESTERLY FLOW. LOW-LEVEL TEMPERATURES ARE PROGGED TO BE IN THE
-4 TO -10C RANGE AND SATURATED...WITH WITH DRY AIR IN PLACE IN THE
MID-LEVEL...TYPICAL OF A FREEZING DRIZZLE SOUNDING. EXPECT AREAS OF
FREEZING DRIZZLE WITH A CHANCE FOR SOME LIGHT SNOW/FLURRIES MIXED IN
A TIMES....ESPECIALLY ALONG THE UPSLOPE AREAS OF THE WESTERN
SOUTHERN TIER AND THE TUG HILL AREA. BY THE AFTERNOON...THE FREEZING
DRIZZLE CHANCES SHOULD RAPIDLY COME TO AN END AS COLDER AIR
CONTINUES TO ADVECT INTO THE AREA...PUSHING THE LOW-LEVEL
TEMPERATURES INTO THE DENDRITIC GROWTH TEMPERATURE RANGE...ALLOWING
FOR A CHANGE OVER TO SNOW ACROSS THE AREA.
TEMPERATURES ON SUNDAY WILL BE FAIRLY STAGNANT IN THE LOW 20S
THROUGH THE MORNING...THEN WILL START TO FALL THROUGH THE AFTERNOON
AS THE TRUE ARCTIC SOURCED AIR FINALLY STARTS TO PUSH INTO WESTERN
NEW YORK. THE BOTTOM WILL FALL OUT SUNDAY EVENING AS TEMPERATURES
PLUNGE TOWARD ZERO BY MIDNIGHT AS THE CORE OF THE -24C TO -30C 850
MB AIR ARRIVES. ACCOMPANYING THE ARCTIC FRONT...WILL BE SOME
INCREASED WINDS AS THE PRESSURE GRADIENT TIGHTENS BETWEEN AN
IMPRESSIVE 1049MB HIGH OVER THE CENTRAL CONUS AND THE 999MB LOW OVER
NEW BRUNSWICK. THE COMBINATION OF TEMPERATURES PLUNGING AND STEADY
WINDS IN THE CAA ACROSS THE AREA WILL LIKELY PROMPT ANOTHER PERIOD
OF BITTER WIND CHILLS THAT WILL EVENTUALLY NEED HEADLINES ONCE
CONFIDENCE ON THE MAGNITUDE OF THE WIND CHILLS IMPROVES.
LAKE EFFECT SNOW POTENTIAL OFF OF LAKE ONTARIO...
ONCE THE ARCTIC AIR STARTS WORKING ACROSS THE LAKE SUNDAY AFTERNOON
AND EVENING...LAKE EFFECT SNOWS WILL PICK UP ALONG THE SOUTHEAST
SHORE. LAKE PARAMETERS SHOW THE EQUILIBRIUM LEVELS RISING TO 5-8KFT
LATE SUNDAY...THEN PICKING UP OVERNIGHT TO 10KFT OR SO BY MONDAY
MORNING...BEFORE THE CAPPING INVERSION QUICKLY LOWERS LATE MONDAY
AFTERNOON WITH RISING HEIGHTS / SUBSIDENCE UNDER THE BUILDING RIDGE.
THE MEAN NORTHWEST FLOW DURING THIS TIME PERIOD WILL CONCENTRATE THE
HEAVIEST LAKE SNOWS FROM EASTERN NIAGARA COUNTY ACROSS TO SOUTHWEST
OSWEGO COUNTY...SIMILAR TO THE MOST RECENT LAKE EFFECT EVENT. EXPECT
THE HIGHEST SNOW ACCUMULATIONS WILL BE IMMEDIATELY ALONG THE LAKE
SHORE...AND WILL TAPER OFF QUICKLY INLAND...DUE TO THE MULTIBANDED
STRUCTURE AND THE REDUCED FETCH DUE SOME ICE COVER ON LAKE ONTARIO.
SHOULD THESE LAKE PARAMETERS HOLD...ADVISORY HEADLINES MAY
EVENTUALLY BE NEEDED MAINLY FOR LOCATIONS IMMEDIATELY ALONG THE LAKE
SHORE.
TEMPERATURES ON MONDAY...
FORECAST CONFIDENCE IS HIGH IN ANOTHER ROUND OF POTENTIALLY RECORD
SETTING COLD AIR FOR MONDAY. GLOBAL MODELS AND THEIR ENSEMBLES ARE
IN EXCELLENT AGREEMENT ON A STRONG 500 MB LOW PASSING NORTH OF NEW
YORK DURING THE DAY MONDAY. NAEFS PERCENTILES SHOW FORECAST 850 MB
TEMPERATURES ONCE AGAIN REACH RECORD VALUES FOR THE 1979-2009
CLIMATE PERIOD. THIS WILL TRANSLATE TO LOW TEMPERATURES MONDAY
MORNING AND AGAIN TUESDAY MORNING RANGING FROM AROUND 0 NEAR LAKE
ONTARIO TO TEENS BELOW ZERO AWAY FROM THE LAKE. HIGH TEMPERATURES ON
MONDAY WILL LIKELY REMAIN WITHIN A FEW DEGREES EITHER SIDE OF 0.
&&
.LONG TERM /TUESDAY THROUGH FRIDAY/...
WHILE TEMPERATURES DURING THIS PERIOD WILL NOT BE AS BRUTAL AS THEY
HAVE BEEN IN RECENT DAYS...THE PRESENCE OF A DEEP LONGWAVE TROUGH
OVER NORTH AMERICA WITH A CONTINUED FLOW OUT OF THE CANADIAN ARCTIC
WILL KEEP OUR MERCURY AT BELOW NORMAL LEVELS.
A MODERATING SOUTHWESTERLY FLOW BETWEEN HIGH PRESSURE TO OUR SOUTH
AND LOW PRESSURE APPROACHING FROM THE NORTHWEST WILL BRING ANOTHER
SLIGHT WARM-UP WITH HIGH TEMPS BUMPING THE 20 DEGREE MARK IN SOME
SPOTS UPPER TEENS ELSEWHERE.
THE LOW TO THE NORTHWEST WILL BRING ANOTHER ROUND OF SNOW TUESDAY
EVENING THROUGH MUCH OF WEDNESDAY. THERE MAY BE A MODERATE TO
BRIEFLY HEAVY SNOW WITH THE PASSAGE OF AN ARCTIC FRONT ACCOMPANYING
THE LOW. OTHERWISE...SNOW SHOULD BE LIGHT IN NATURE AND NOT POSE
MUCH MORE THAN A FEW INCHES OF ACCUMULATION.
THE COLDER AIR FOLLOWING THE LOW WILL NOT BE NEARLY AS COLD AS IN
RECENT EVENTS. 850MB TEMPS DO FALL TO ABOUT -24C OVER LAKE ONTARIO
ON WEDNESDAY NIGHT AND THURSDAY...AND WITH A WELL ALIGNED WESTERLY
WIND WILL PRODUCE A BAND OF LAKE EFFECT SNOW ALONG THE SOUTH SHORE
INLAND TO CENTRAL NY.
SPRAWLING HIGH PRESSURE CENTERED OVER THE UPPER PLAINS TO
BREADBASKET PROVINCES WILL BUILD EASTWARD ACROSS THE REGION ON
THURSDAY NIGHT AND FRIDAY. THIS WILL DRYING AND SUBSIDENCE TO THE
AREA WITH AN END OF THE LAKE EFFECT AND MORE SUNSHINE...EVEN THE
OPPORTUNITY FOR A WARMING TREND.
&&
.AVIATION /18Z SATURDAY THROUGH THURSDAY/...
THERE WILL BE TW0 BANDS OF LIGHT SNOW WHICH MOVE ACROSS THE REGION
TODAY. THE FIRST EXTENDS FROM R0C-ART AT 18Z WITH THIS FORECAST TO
CONTINUE TO LIFT TO THE NE THROUGH THIS AFTERNOON. BEHIND THIS
WILL BE A BRIEF LULL IN SNOWFALL RATES...FOLLOWED BY ANOTHER BAND
OF STEADIER SNOW LATE AFTERNOON AND INTO THIS EVENING. IN STEADIER
SNOWS...EXPECT IFR OR LOWER CONDITIONS WITH VSBY AVERAGING AROUND
1SM. AFTER THIS...THE MID-LEVELS DRY OUT WITH A POTENTIAL FOR
-FZDZ LATE TONIGHT AND INTO MONDAY. FORECAST CONFIDENCE IN THIS IS
MARGINAL...WITH A CHANCE THAT PRECIPITATION WILL NOT MATERIALIZE.
EXPECT IFR-MVFR CIGS THROUGH 12Z. AFTER THIS...INCREASING SW WINDS
SHOULD HELP MIX LOW LEVEL MOISTURE...WITH LIFTING CIGS SUNDAY MORNING.
OUTLOOK...
SUNDAY NIGHT...SCATTERED SNOW SHOWERS WITH MVFR/IFR POSSIBLE.
MONDAY...MVFR/IFR IN LAKE SNOW SOUTH OF LAKE ONTARIO. VFR
ELSEWHERE.
TUESDAY...VFR.
WEDNESDAY AND THURSDAY...SCATTERED SNOW SHOWERS WITH MVFR/IFR POSSIBLE.
&&
.MARINE...
RELATIVELY TRANQUIL CONDITIONS ON LAKE ONTARIO WILL PERSIST
THROUGH TONIGHT AS A WEAK AREA OF LOW PRESSURE CROSSES THE REGION.
FRESHENING WESTERLY FLOW WILL DEVELOP BEHIND THE PASSING LOW SUNDAY
AFTERNOON. AN ARCTIC FRONT DROPPING ACROSS THE LAKES SUNDAY NIGHT
WILL LIKELY BRING ANOTHER ROUND OF SMALL CRAFT ADVISORIES WITH BRISK
WNW FLOW LASTING THROUGH MONDAY WITH WINDS BACKING TO THE SW TUESDAY
AHEAD OF ANOTHER CLIPPER THAT IS EXPECTED TO PASS NORTH OF THE GREAT
LAKES.
&&
.BUF WATCHES/WARNINGS/ADVISORIES...
NY...WINTER WEATHER ADVISORY UNTIL 10 AM EST SUNDAY FOR NYZ001-002-
006>008-010>012-019>021-085.
MARINE...NONE.
&&
$$
SYNOPSIS...WOOD
NEAR TERM...APFFEL
SHORT TERM...CHURCH
LONG TERM...CHURCH/WCH
AVIATION...APFFEL
MARINE...APFFEL/WOOD
AREA FORECAST DISCUSSION
NWS BUFFALO NY
1128 AM EST SAT FEB 21 2015
.SYNOPSIS...
AN ELONGATED AREA OF LOW PRESSURE OVER THE CENTRAL UNITED STATES
WILL CROSS THE GREAT LAKES TODAY BRINGING WIDESPREAD...MAINLY
LIGHT...SNOWFALL TO WESTERN AND NORTH CENTRAL NEW YORK TODAY INTO
TONIGHT ALONG WITH RELATIVELY WARMER TEMPERATURES IN THE 20S. AREAS
OF FREEZING DRIZZLE WILL BE POSSIBLE IN THE WAKE OF THE SYSTEM LATER
TONIGHT INTO SUNDAY BEFORE TEMPERATURES PLUNGE SUNDAY NIGHT AS
ANOTHER ARCTIC FRONT SWEEPS ACROSS THE GREAT LAKES...BRINGING
POTENTIALLY RECORD BREAKING COLD ALONG WITH LAKE EFFECT SNOW SHOWERS
BY MONDAY. WHILE MONDAY WILL BE THE COLDEST DAY OF THE
PERIOD...TEMPERATURES ARE EXPECTED TO REMAIN BELOW AVERAGE THROUGH
NEXT WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
AT 1100 AM...LIGHT SNOW HAS SPREAD ACROSS MUCH OF WESTERN NEW
YORK...WITH LIGHT SNOW EXPECTED TO CONTINUE TO SPREAD ACROSS THE
REMAINDER OF THE CWA BY EARLY AFTERNOON. SYNOPTIC SUPPORT STEMS
FROM A BROAD AREA OF WARM AIR ADVECTION...WITH SOME MODEST UPPER
LEVEL SUPPORT FROM A SHORTWAVE EMBEDDED IN A CYCLONIC FLOW. RADAR
SHOWS SOME LOW LEVEL ENHANCEMENT FROM WESTERN LAKE ERIE...ACROSS SOUTHERN
ONTARIO...AND INTO THE NIAGARA FRONTIER. THIS IS NOT UNCOMMON FOR
THESE AREAS WHEN THERE IS A SOUTHERLY FLOW...WHICH DOWNSLOPES
ACROSS THE CHAUTAUQUA RIDGE...BUT THEN ENHANCES LIFT IN THE
AFOREMENTIONED REGIONS. HIGH RESOLUTION GUIDANCE CAPTURES
THIS...WITH THIS ENHANCEMENT LIKELY CONTINUE THROUGH EARLY
AFTERNOON WHEN WINDS DIMINISH AND SHIFT TO THE SSW.
OTHERWISE...STEADIEST SNOWS SHOULD BE ACROSS WESTERN PORTIONS OF
THE SOUTHERN TIER THROUGH EARLY AFTERNOON WHERE THERE IS THE MOST
MOISTURE AND SYNOPTIC SCALE LIFT. THE HRRR SEEMS TO HAVE A GOOD
HANDLE ON THESE TRENDS...BUT IS RUNNING ABOUT AN HOUR SLOW WITH
ITS TIMING.
DUE TO BOTH THE THREAT FOR FREEZING DRIZZLE LATE TONIGHT AND THE
GENERAL LIGHT SNOW HAVE EXPANDED THE WINTER WEATHER ADVISORY FOR
MUCH OF WESTERN NEW YORK. HAVE ALSO EXTENDED THE TIMING OF THE
ADVISORY AND ADDED JEFFERSON COUNTY FOR THE EASTERN LAKE ONTARIO
REGION. IN THESE AREAS ADDED...SNOW AMOUNTS WILL BE MARGINAL TO
ADVISORY CRITERIA...BUT THERE SHOULD BE AT LEAST 2 OR 3
INCHES...WITH UP TO 5 INCHES IN NIAGARA COUNTY...AND IN
CHAUTAUQUA/CATTARAUGUS COUNTIES. THERE WILL BE LESSER AMOUNTS OF
SNOW AND A LESSER FREEZING DRIZZLE THREAT FOR THE GENESEE
VALLEY...SO HAVE LEFT THESE AREAS OUT OF THE ADVISORY FOR NOW.
EXPECT SNOWFALL TO BE ACCORDINGLY LIGHT WITH MOST AREAS SEEING A
GENERAL 2 TO 4 INCHES THROUGH THIS EVENING. SOUTHERLY DOWNSLOPING
IN THE VICINITY OF THE FINGER LAKES MAY RESULT IN ACCUMULATIONS ON
THE LOWER END OF THESE VALUES WHILE SIMILAR UPSLOPING ONTO THE TUG
HILL PLATEAU SHOULD YIELD SLIGHTLY HIGHER ACCUMULATIONS IN THE
NEIGHBORHOOD OF 4 TO 7 INCHES THROUGH TONIGHT.
SNOW WILL TAPER OFF FROM WEST TO EAST AS THE UPPER LEVEL JET AND
DEEPER MOISTURE TRANSLATES TO THE EAST COAST. EVEN AS THE DEEPER
MID-LEVEL MOISTURE IS STRIPPED OUT...WEAK ASCENT DUE TO
APPROACHING MID/UPPER LEVEL TROUGHING ALONG WITH WESTERLY UPSLOPE
FLOW MAY RESULT IN A TRANSITION FROM LINGERING SNOW SHOWERS TO
AREAS OF FREEZING DRIZZLE LATER ON TONIGHT...PARTICULARLY ACROSS
UPSLOPE AREAS OF WESTERN NEW YORK AND EVENTUALLY THE NORTH
COUNTRY.
REGARDING TEMPERATURES...AFOREMENTIONED WARM ADVECTION WILL CONTINUE
TO PUSH TEMPERATURES UPWARDS THROUGH THE DAY TODAY WITH HIGHS
CLIMBING INTO THE 20S BY THIS AFTERNOON. TEMPERATURES WILL CONTINUE
TO CLIMB INTO THE UPPER 20S TONIGHT AS THE WARMEST AIR SURGES NORTH
ACROSS THE REGION IN ADVANCE OF A SURFACE COLD FRONT THAT CROSSES
THE REGION SUNDAY.
&&
.SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/...
SUNDAY WILL START OFF WITH WITH BROAD CYCLONIC FLOW ALOFT AND A COLD
AIR ADVECTION REGIME BEHIND THE DEPARTING SURFACE LOW. FORECAST
SOUNDINGS INDICATE THAT MID-LEVEL DRY AIR WILL BE IN PLACE ACROSS
WESTERN AND CENTRAL NEW YORK...WITH PLENTIFUL LOW-LEVEL MOISTURE IN
THE WESTERLY FLOW. LOW-LEVEL TEMPERATURES ARE PROGGED TO BE IN THE
-4 TO -10C RANGE AND SATURATED...WITH WITH DRY AIR IN PLACE IN THE
MID-LEVEL...TYPICAL OF A FREEZING DRIZZLE SOUNDING. EXPECT AREAS OF
FREEZING DRIZZLE WITH A CHANCE FOR SOME LIGHT SNOW/FLURRIES MIXED IN
A TIMES....ESPECIALLY ALONG THE UPSLOPE AREAS OF THE WESTERN
SOUTHERN TIER AND THE TUG HILL AREA. BY THE AFTERNOON...THE FREEZING
DRIZZLE CHANCES SHOULD RAPIDLY COME TO AN END AS COLDER AIR
CONTINUES TO ADVECT INTO THE AREA...PUSHING THE LOW-LEVEL
TEMPERATURES INTO THE DENDRITIC GROWTH TEMPERATURE RANGE...ALLOWING
FOR A CHANGE OVER TO SNOW ACROSS THE AREA.
TEMPERATURES ON SUNDAY WILL BE FAIRLY STAGNANT IN THE LOW 20S
THROUGH THE MORNING...THEN WILL START TO FALL THROUGH THE AFTERNOON
AS THE TRUE ARCTIC SOURCED AIR FINALLY STARTS TO PUSH INTO WESTERN
NEW YORK. THE BOTTOM WILL FALL OUT SUNDAY EVENING AS TEMPERATURES
PLUNGE TOWARD ZERO BY MIDNIGHT AS THE CORE OF THE -24C TO -30C 850
MB AIR ARRIVES. ACCOMPANYING THE ARCTIC FRONT...WILL BE SOME
INCREASED WINDS AS THE PRESSURE GRADIENT TIGHTENS BETWEEN AN
IMPRESSIVE 1049MB HIGH OVER THE CENTRAL CONUS AND THE 999MB LOW OVER
NEW BRUNSWICK. THE COMBINATION OF TEMPERATURES PLUNGING AND STEADY
WINDS IN THE CAA ACROSS THE AREA WILL LIKELY PROMPT ANOTHER PERIOD
OF BITTER WIND CHILLS THAT WILL EVENTUALLY NEED HEADLINES ONCE
CONFIDENCE ON THE MAGNITUDE OF THE WIND CHILLS IMPROVES.
LAKE EFFECT SNOW POTENTIAL OFF OF LAKE ONTARIO...
ONCE THE ARCTIC AIR STARTS WORKING ACROSS THE LAKE SUNDAY AFTERNOON
AND EVENING...LAKE EFFECT SNOWS WILL PICK UP ALONG THE SOUTHEAST
SHORE. LAKE PARAMETERS SHOW THE EQUILIBRIUM LEVELS RISING TO 5-8KFT
LATE SUNDAY...THEN PICKING UP OVERNIGHT TO 10KFT OR SO BY MONDAY
MORNING...BEFORE THE CAPPING INVERSION QUICKLY LOWERS LATE MONDAY
AFTERNOON WITH RISING HEIGHTS / SUBSIDENCE UNDER THE BUILDING RIDGE.
THE MEAN NORTHWEST FLOW DURING THIS TIME PERIOD WILL CONCENTRATE THE
HEAVIEST LAKE SNOWS FROM EASTERN NIAGARA COUNTY ACROSS TO SOUTHWEST
OSWEGO COUNTY...SIMILAR TO THE MOST RECENT LAKE EFFECT EVENT. EXPECT
THE HIGHEST SNOW ACCUMULATIONS WILL BE IMMEDIATELY ALONG THE LAKE
SHORE...AND WILL TAPER OFF QUICKLY INLAND...DUE TO THE MULTIBANDED
STRUCTURE AND THE REDUCED FETCH DUE SOME ICE COVER ON LAKE ONTARIO.
SHOULD THESE LAKE PARAMETERS HOLD...ADVISORY HEADLINES MAY
EVENTUALLY BE NEEDED MAINLY FOR LOCATIONS IMMEDIATELY ALONG THE LAKE
SHORE.
TEMPERATURES ON MONDAY...
FORECAST CONFIDENCE IS HIGH IN ANOTHER ROUND OF POTENTIALLY RECORD
SETTING COLD AIR FOR MONDAY. GLOBAL MODELS AND THEIR ENSEMBLES ARE
IN EXCELLENT AGREEMENT ON A STRONG 500 MB LOW PASSING NORTH OF NEW
YORK DURING THE DAY MONDAY. NAEFS PERCENTILES SHOW FORECAST 850 MB
TEMPERATURES ONCE AGAIN REACH RECORD VALUES FOR THE 1979-2009
CLIMATE PERIOD. THIS WILL TRANSLATE TO LOW TEMPERATURES MONDAY
MORNING AND AGAIN TUESDAY MORNING RANGING FROM AROUND 0 NEAR LAKE
ONTARIO TO TEENS BELOW ZERO AWAY FROM THE LAKE. HIGH TEMPERATURES ON
MONDAY WILL LIKELY REMAIN WITHIN A FEW DEGREES EITHER SIDE OF 0.
&&
.LONG TERM /TUESDAY THROUGH FRIDAY/...
WHILE TEMPERATURES DURING THIS PERIOD WILL NOT BE AS BRUTAL AS THEY
HAVE BEEN IN RECENT DAYS...THE PRESENCE OF A DEEP LONGWAVE TROUGH
OVER NORTH AMERICA WITH A CONTINUED FLOW OUT OF THE CANADIAN ARCTIC
WILL KEEP OUR MERCURY AT BELOW NORMAL LEVELS.
A MODERATING SOUTHWESTERLY FLOW BETWEEN HIGH PRESSURE TO OUR SOUTH
AND LOW PRESSURE APPROACHING FROM THE NORTHWEST WILL BRING ANOTHER
SLIGHT WARM-UP WITH HIGH TEMPS BUMPING THE 20 DEGREE MARK IN SOME
SPOTS UPPER TEENS ELSEWHERE.
THE LOW TO THE NORTHWEST WILL BRING ANOTHER ROUND OF SNOW TUESDAY
EVENING THROUGH MUCH OF WEDNESDAY. THERE MAY BE A MODERATE TO
BRIEFLY HEAVY SNOW WITH THE PASSAGE OF AN ARCTIC FRONT ACCOMPANYING
THE LOW. OTHERWISE...SNOW SHOULD BE LIGHT IN NATURE AND NOT POSE
MUCH MORE THAN A FEW INCHES OF ACCUMULATION.
THE COLDER AIR FOLLOWING THE LOW WILL NOT BE NEARLY AS COLD AS IN
RECENT EVENTS. 850MB TEMPS DO FALL TO ABOUT -24C OVER LAKE ONTARIO
ON WEDNESDAY NIGHT AND THURSDAY...AND WITH A WELL ALIGNED WESTERLY
WIND WILL PRODUCE A BAND OF LAKE EFFECT SNOW ALONG THE SOUTH SHORE
INLAND TO CENTRAL NY.
SPRAWLING HIGH PRESSURE CENTERED OVER THE UPPER PLAINS TO
BREADBASKET PROVINCES WILL BUILD EASTWARD ACROSS THE REGION ON
THURSDAY NIGHT AND FRIDAY. THIS WILL DRYING AND SUBSIDENCE TO THE
AREA WITH AN END OF THE LAKE EFFECT AND MORE SUNSHINE...EVEN THE
OPPORTUNITY FOR A WARMING TREND.
&&
.AVIATION /18Z SATURDAY THROUGH THURSDAY/...
LIGHT SNOW WILL SPREAD ACROSS WRN/NCTRL NY TODAY AHEAD OF AN AREA OF
LOW PRESSURE CROSSING THE GREAT LAKES. EXPECT CONDITIONS TO
DETERIORATE TO IFR VSBYS THROUGH EARLY AFTERNOON...WITH VSBY
LOWERING TO 1-2SM IN LIGHT SNOW. CONDITIONS SHOULD IMPROVE
SOMEWHAT WITH THE PASSAGE OF THE LOW CENTER AS MAIN AREA OF
ISENTROPIC LIFT MOVES OFF TO THE EAST...HOWEVER WINDS WILL ALSO
BECOME WESTERLY...ALLOW FOR UPSLOPE MVFR CIGS TO LINGER. IN
ADDITION...AS MID-LEVEL MOISTURE IS STRIPPED OUT BEHIND THE LOW
THERE WILL BE A POTENTIAL FOR -FZDZ TO DEVELOP LATER TONIGHT AND
LINGER INTO SUNDAY MORNING.
OUTLOOK...
SATURDAY OVERNIGHT...MVFR/IFR WITH SNOW LIKELY.
SUNDAY...SCATTERED SNOW SHOWERS WITH MVFR/IFR POSSIBLE.
MONDAY...MVFR/IFR IN LAKE SNOW SOUTH OF LAKE ONTARIO. VFR
ELSEWHERE.
TUESDAY...VFR.
WEDNESDAY...SCATTERED SNOW SHOWERS WITH MVFR/IFR POSSIBLE.
&&
.MARINE...
WINDS SHOULD REMAIN RELATIVELY LIGHT OVER THE LAKES AS RELATIVELY
WARM AIR SURGING NORTHWARDS ACROSS THE REGION WILL HELP KEEP
STRONGER WINDS ALOFT. RELATIVELY TRANQUIL CONDITIONS ON LAKE
ONTARIO WILL PERSIST THROUGH TONIGHT AS A WEAK AREA OF LOW
PRESSURE CROSSES THE REGION.
FRESHENING WESTERLY FLOW WILL DEVELOP BEHIND THE PASSING LOW SUNDAY
AFTERNOON. AN ARCTIC FRONT DROPPING ACROSS THE LAKES SUNDAY NIGHT
WILL LIKELY BRING ANOTHER ROUND OF SMALL CRAFT ADVISORIES WITH BRISK
WNW FLOW LASTING THROUGH MONDAY WITH WINDS BACKING TO THE SW TUESDAY
AHEAD OF ANOTHER CLIPPER THAT IS EXPECTED TO PASS NORTH OF THE GREAT
LAKES.
&&
.BUF WATCHES/WARNINGS/ADVISORIES...
NY...WINTER WEATHER ADVISORY UNTIL 10 AM EST SUNDAY FOR NYZ001-002-
006>008-010>012-019>021-085.
MARINE...NONE.
&&
$$
SYNOPSIS...WOOD
NEAR TERM...APFFEL/WOOD
SHORT TERM...CHURCH
LONG TERM...CHURCH/WCH
AVIATION...APFFEL/WOOD
MARINE...WOOD
AREA FORECAST DISCUSSION
NWS BUFFALO NY
1007 AM EST SAT FEB 21 2015
.SYNOPSIS...
AN ELONGATED AREA OF LOW PRESSURE OVER THE CENTRAL UNITED STATES
WILL CROSS THE GREAT LAKES TODAY BRINGING WIDESPREAD...MAINLY
LIGHT...SNOWFALL TO WESTERN AND NORTH CENTRAL NEW YORK TODAY INTO
TONIGHT ALONG WITH RELATIVELY WARMER TEMPERATURES IN THE 20S. AREAS
OF FREEZING DRIZZLE WILL BE POSSIBLE IN THE WAKE OF THE SYSTEM LATER
TONIGHT INTO SUNDAY BEFORE TEMPERATURES PLUNGE SUNDAY NIGHT AS
ANOTHER ARCTIC FRONT SWEEPS ACROSS THE GREAT LAKES...BRINGING
POTENTIALLY RECORD BREAKING COLD ALONG WITH LAKE EFFECT SNOW SHOWERS
BY MONDAY. WHILE MONDAY WILL BE THE COLDEST DAY OF THE
PERIOD...TEMPERATURES ARE EXPECTED TO REMAIN BELOW AVERAGE THROUGH
NEXT WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
AT 1000 AM...LIGHT SNOW HAS STARTED TO SPREAD INTO FAR WESTERN NEW
YORK...WITH THIS AREA EXPECTED TO CONTINUE TO SPREAD AND ACROSS
THE ENTIRE CWA BY EARLY AFTERNOON. SYNOPTIC SUPPORT STEMS FROM A
BROAD AREA OF WARM AIR ADVECTION...WITH SOME MODEST UPPER LEVEL
SUPPORT WITH A MODEST SHORTWAVE EMBEDDED IN A CYCLONIC FLOW. RADAR
SHOWS SOME LOW LEVEL ENHANCEMENT ACROSS SOUTHERN ONTARIO AND INTO
THE NIAGARA FRONTIER WHICH OFTEN DEVELOPS IN THIS AREAS WHEN THERE
IS A SOUTHERLY FLOW. HIGH RESOLUTION GUIDANCE CAPTURES
THIS...WITH THIS ENHANCEMENT LIKELY CONTINUE THROUGH 18Z OR
SO...WHEN WINDS DIMINISH AND SHIFT TO THE SSW. OTHERWISE...STEADIEST
SNOWS SHOULD BE ACROSS WESTERN PORTIONS OF THE SOUTHERN TIER
THROUGH EARLY AFTERNOON WHERE THERE IS THE MOST MOISTURE AND
SYNOPTIC SCALE LIFT. THE HRRR SEEMS TO HAVE A GOOD HANDLE ON THESE
TRENDS...BUT IS RUNNING ABOUT AN HOUR SLOW WITH ITS TIMING.
EXPECT SNOWFALL TO BE ACCORDINGLY LIGHT WITH MOST AREAS SEEING A
GENERAL 2 TO 4 INCHES THROUGH THIS EVENING. SOUTHERLY DOWNSLOPING
IN THE VICINITY OF THE FINGER LAKES MAY RESULT IN ACCUMULATIONS ON
THE LOWER END OF THESE VALUES WHILE SIMILAR UPSLOPING ONTO THE TUG
HILL PLATEAU SHOULD YIELD SLIGHTLY HIGHER ACCUMULATIONS IN THE
NEIGHBORHOOD OF 4 TO 7 INCHES THROUGH TONIGHT. HENCE A WINTER
WEATHER ADVISORY HAS BEEN ISSUED FOR OSWEGO/LEWIS COUNTIES TO
COVER THESE SLIGHTLY HIGHER ACCUMULATIONS.
SNOW WILL TAPER OFF FROM WEST TO EAST AS THE UPPER LEVEL JET AND
DEEPER MOISTURE TRANSLATES TO THE EAST COAST. EVEN AS THE DEEPER
MID-LEVEL MOISTURE IS STRIPPED OUT...WEAK ASCENT DUE TO APPROACHING
MID/UPPER LEVEL TROUGHING ALONG WITH WESTERLY UPSLOPE FLOW MAY
RESULT IN A TRANSITION FROM LINGERING SNOW SHOWERS TO AREAS OF
FREEZING DRIZZLE LATER ON TONIGHT...PARTICULARLY ACROSS UPSLOPE
AREAS OF WESTERN NEW YORK AND EVENTUALLY THE NORTH COUNTRY.
REGARDING TEMPERATURES...AFOREMENTIONED WARM ADVECTION WILL CONTINUE
TO PUSH TEMPERATURES UPWARDS THROUGH THE DAY TODAY WITH HIGHS
CLIMBING INTO THE 20S BY THIS AFTERNOON. TEMPERATURES WILL CONTINUE
TO CLIMB INTO THE UPPER 20S TONIGHT AS THE WARMEST AIR SURGES NORTH
ACROSS THE REGION IN ADVANCE OF A SURFACE COLD FRONT THAT CROSSES
THE REGION SUNDAY.
&&
.SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/...
SUNDAY WILL START OFF WITH WITH BROAD CYCLONIC FLOW ALOFT AND A COLD
AIR ADVECTION REGIME BEHIND THE DEPARTING SURFACE LOW. FORECAST
SOUNDINGS INDICATE THAT MID-LEVEL DRY AIR WILL BE IN PLACE ACROSS
WESTERN AND CENTRAL NEW YORK...WITH PLENTIFUL LOW-LEVEL MOISTURE IN
THE WESTERLY FLOW. LOW-LEVEL TEMPERATURES ARE PROGGED TO BE IN THE
-4 TO -10C RANGE AND SATURATED...WITH WITH DRY AIR IN PLACE IN THE
MID-LEVEL...TYPICAL OF A FREEZING DRIZZLE SOUNDING. EXPECT AREAS OF
FREEZING DRIZZLE WITH A CHANCE FOR SOME LIGHT SNOW/FLURRIES MIXED IN
A TIMES....ESPECIALLY ALONG THE UPSLOPE AREAS OF THE WESTERN
SOUTHERN TIER AND THE TUG HILL AREA. BY THE AFTERNOON...THE FREEZING
DRIZZLE CHANCES SHOULD RAPIDLY COME TO AN END AS COLDER AIR
CONTINUES TO ADVECT INTO THE AREA...PUSHING THE LOW-LEVEL
TEMPERATURES INTO THE DENDRITIC GROWTH TEMPERATURE RANGE...ALLOWING
FOR A CHANGE OVER TO SNOW ACROSS THE AREA.
TEMPERATURES ON SUNDAY WILL BE FAIRLY STAGNANT IN THE LOW 20S
THROUGH THE MORNING...THEN WILL START TO FALL THROUGH THE AFTERNOON
AS THE TRUE ARCTIC SOURCED AIR FINALLY STARTS TO PUSH INTO WESTERN
NEW YORK. THE BOTTOM WILL FALL OUT SUNDAY EVENING AS TEMPERATURES
PLUNGE TOWARD ZERO BY MIDNIGHT AS THE CORE OF THE -24C TO -30C 850
MB AIR ARRIVES. ACCOMPANYING THE ARCTIC FRONT...WILL BE SOME
INCREASED WINDS AS THE PRESSURE GRADIENT TIGHTENS BETWEEN AN
IMPRESSIVE 1049MB HIGH OVER THE CENTRAL CONUS AND THE 999MB LOW OVER
NEW BRUNSWICK. THE COMBINATION OF TEMPERATURES PLUNGING AND STEADY
WINDS IN THE CAA ACROSS THE AREA WILL LIKELY PROMPT ANOTHER PERIOD
OF BITTER WIND CHILLS THAT WILL EVENTUALLY NEED HEADLINES ONCE
CONFIDENCE ON THE MAGNITUDE OF THE WIND CHILLS IMPROVES.
LAKE EFFECT SNOW POTENTIAL OFF OF LAKE ONTARIO...
ONCE THE ARCTIC AIR STARTS WORKING ACROSS THE LAKE SUNDAY AFTERNOON
AND EVENING...LAKE EFFECT SNOWS WILL PICK UP ALONG THE SOUTHEAST
SHORE. LAKE PARAMETERS SHOW THE EQUILIBRIUM LEVELS RISING TO 5-8KFT
LATE SUNDAY...THEN PICKING UP OVERNIGHT TO 10KFT OR SO BY MONDAY
MORNING...BEFORE THE CAPPING INVERSION QUICKLY LOWERS LATE MONDAY
AFTERNOON WITH RISING HEIGHTS / SUBSIDENCE UNDER THE BUILDING RIDGE.
THE MEAN NORTHWEST FLOW DURING THIS TIME PERIOD WILL CONCENTRATE THE
HEAVIEST LAKE SNOWS FROM EASTERN NIAGARA COUNTY ACROSS TO SOUTHWEST
OSWEGO COUNTY...SIMILAR TO THE MOST RECENT LAKE EFFECT EVENT. EXPECT
THE HIGHEST SNOW ACCUMULATIONS WILL BE IMMEDIATELY ALONG THE LAKE
SHORE...AND WILL TAPER OFF QUICKLY INLAND...DUE TO THE MULTIBANDED
STRUCTURE AND THE REDUCED FETCH DUE SOME ICE COVER ON LAKE ONTARIO.
SHOULD THESE LAKE PARAMETERS HOLD...ADVISORY HEADLINES MAY
EVENTUALLY BE NEEDED MAINLY FOR LOCATIONS IMMEDIATELY ALONG THE LAKE
SHORE.
TEMPERATURES ON MONDAY...
FORECAST CONFIDENCE IS HIGH IN ANOTHER ROUND OF POTENTIALLY RECORD
SETTING COLD AIR FOR MONDAY. GLOBAL MODELS AND THEIR ENSEMBLES ARE
IN EXCELLENT AGREEMENT ON A STRONG 500 MB LOW PASSING NORTH OF NEW
YORK DURING THE DAY MONDAY. NAEFS PERCENTILES SHOW FORECAST 850 MB
TEMPERATURES ONCE AGAIN REACH RECORD VALUES FOR THE 1979-2009
CLIMATE PERIOD. THIS WILL TRANSLATE TO LOW TEMPERATURES MONDAY
MORNING AND AGAIN TUESDAY MORNING RANGING FROM AROUND 0 NEAR LAKE
ONTARIO TO TEENS BELOW ZERO AWAY FROM THE LAKE. HIGH TEMPERATURES ON
MONDAY WILL LIKELY REMAIN WITHIN A FEW DEGREES EITHER SIDE OF 0.
&&
.LONG TERM /TUESDAY THROUGH FRIDAY/...
WHILE TEMPERATURES DURING THIS PERIOD WILL NOT BE AS BRUTAL AS THEY
HAVE BEEN IN RECENT DAYS...THE PRESENCE OF A DEEP LONGWAVE TROUGH
OVER NORTH AMERICA WITH A CONTINUED FLOW OUT OF THE CANADIAN ARCTIC
WILL KEEP OUR MERCURY AT BELOW NORMAL LEVELS.
A MODERATING SOUTHWESTERLY FLOW BETWEEN HIGH PRESSURE TO OUR SOUTH
AND LOW PRESSURE APPROACHING FROM THE NORTHWEST WILL BRING ANOTHER
SLIGHT WARM-UP WITH HIGH TEMPS BUMPING THE 20 DEGREE MARK IN SOME
SPOTS UPPER TEENS ELSEWHERE.
THE LOW TO THE NORTHWEST WILL BRING ANOTHER ROUND OF SNOW TUESDAY
EVENING THROUGH MUCH OF WEDNESDAY. THERE MAY BE A MODERATE TO
BRIEFLY HEAVY SNOW WITH THE PASSAGE OF AN ARCTIC FRONT ACCOMPANYING
THE LOW. OTHERWISE...SNOW SHOULD BE LIGHT IN NATURE AND NOT POSE
MUCH MORE THAN A FEW INCHES OF ACCUMULATION.
THE COLDER AIR FOLLOWING THE LOW WILL NOT BE NEARLY AS COLD AS IN
RECENT EVENTS. 850MB TEMPS DO FALL TO ABOUT -24C OVER LAKE ONTARIO
ON WEDNESDAY NIGHT AND THURSDAY...AND WITH A WELL ALIGNED WESTERLY
WIND WILL PRODUCE A BAND OF LAKE EFFECT SNOW ALONG THE SOUTH SHORE
INLAND TO CENTRAL NY.
SPRAWLING HIGH PRESSURE CENTERED OVER THE UPPER PLAINS TO
BREADBASKET PROVINCES WILL BUILD EASTWARD ACROSS THE REGION ON
THURSDAY NIGHT AND FRIDAY. THIS WILL DRYING AND SUBSIDENCE TO THE
AREA WITH AN END OF THE LAKE EFFECT AND MORE SUNSHINE...EVEN THE
OPPORTUNITY FOR A WARMING TREND.
&&
.AVIATION /15Z SATURDAY THROUGH WEDNESDAY/...
LIGHT SNOW WILL SPREAD ACROSS WRN/NCTRL NY TODAY AHEAD OF AN AREA OF
LOW PRESSURE CROSSING THE GREAT LAKES. EXPECT CONDITIONS TO
DETERIORATE TO IFR VSBYS THROUGH EARLY AFTERNOON...WITH VSBY
LOWERING TO 1-2SM IN LIGHT SNOW. CONDITIONS SHOULD IMPROVE
SOMEWHAT WITH THE PASSAGE OF THE LOW CENTER AS MAIN AREA OF
ISENTROPIC LIFT MOVES OFF TO THE EAST...HOWEVER WINDS WILL ALSO
BECOME WESTERLY...ALLOW FOR UPSLOPE MVFR CIGS TO LINGER. IN
ADDITION...AS MID-LEVEL MOISTURE IS STRIPPED OUT BEHIND THE LOW
THERE WILL BE A POTENTIAL FOR -FZDZ TO DEVELOP LATER TONIGHT AND
LINGER INTO SUNDAY MORNING.
OUTLOOK...
SATURDAY OVERNIGHT...MVFR/IFR WITH SNOW LIKELY.
SUNDAY...SCATTERED SNOW SHOWERS WITH MVFR/IFR POSSIBLE.
MONDAY...MVFR/IFR IN LAKE SNOW SOUTH OF LAKE ONTARIO. VFR
ELSEWHERE.
TUESDAY...VFR.
WEDNESDAY...SCATTERED SNOW SHOWERS WITH MVFR/IFR POSSIBLE.
&&
.MARINE...
WINDS SHOULD REMAIN RELATIVELY LIGHT OVER THE LAKES AS RELATIVELY
WARM AIR SURGING NORTHWARDS ACROSS THE REGION WILL HELP KEEP
STRONGER WINDS ALOFT. RELATIVELY TRANQUIL CONDITIONS ON LAKE
ONTARIO WILL PERSIST THROUGH TONIGHT AS A WEAK AREA OF LOW
PRESSURE CROSSES THE REGION.
FRESHENING WESTERLY FLOW WILL DEVELOP BEHIND THE PASSING LOW SUNDAY
AFTERNOON. AN ARCTIC FRONT DROPPING ACROSS THE LAKES SUNDAY NIGHT
WILL LIKELY BRING ANOTHER ROUND OF SMALL CRAFT ADVISORIES WITH BRISK
WNW FLOW LASTING THROUGH MONDAY WITH WINDS BACKING TO THE SW TUESDAY
AHEAD OF ANOTHER CLIPPER THAT IS EXPECTED TO PASS NORTH OF THE GREAT
LAKES.
&&
.BUF WATCHES/WARNINGS/ADVISORIES...
NY...WINTER WEATHER ADVISORY UNTIL 7 AM EST SUNDAY FOR NYZ006-008.
MARINE...NONE.
&&
$$
SYNOPSIS...WOOD
NEAR TERM...APFFEL/WOOD
SHORT TERM...CHURCH
LONG TERM...CHURCH/WCH
AVIATION...APFFEL/WOOD
MARINE...WOOD
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
930 PM EST SUN FEB 22 2015
.SYNOPSIS...
A MILD AND MOIST AIR MASS WILL LIE ACROSS THE AREA INTO TONIGHT.
RAIN ASSOCIATED WITH A COLD FRONTAL PASSAGE WILL BE LIGHT
TONIGHT...BUT WEAK LOW PRESSURE WILL MOVE ALONG THE STALLED
FRONT...SPREADING MORE SIGNIFICANT RAIN NORTHWARD ON MONDAY. COLD
AIR WILL RETURN LATE MONDAY AS ARCTIC HIGH PRESSURE SNEAKS BACK
ACROSS THE REGION INTO TUE. COLD AND UNSETTLED WEATHER IS EXPECTED
DURING THE UPCOMING WEEK AS CHILLY HIGH PRESSURE AND GULF MOISTURE
INTERACT.
&&
.NEAR TERM /UNTIL 6 AM MONDAY MORNING/...
AS OF 930 PM SUNDAY...SCATTERED AREAS OF RAIN IS LEADING A FRONTAL
BOUNDARY THAT WILL SLOWLY PUSH OFF THE COAST BY MORNING. THE AREA
OF RAIN IS PRODUCING TOTAL OF LESS THAN A TENTH OF AN INCH. THE
LATEST RUN OF THE HRRR IS SHOWING THE COVERAGE OF THE RAIN
BECOMING MORE WIDESPREAD OVERNIGHT. TEMPERATURES ARE EXPECTED TO
FALL ONLY TO AROUND 40 IN THE NORTHWEST TO THE UPPER 40S SOUTH AND
WEST OF MYRTLE BEACH.
&&
.SHORT TERM /6 AM MONDAY MORNING THROUGH TUESDAY NIGHT/...
AS OF 330 PM SUNDAY...WAVE OF LOW PRESSURE RIDING ALONG
LINGERING FRONT MON MORNING WILL MOVE OUT OF AREA MON AFTN AS HIGH
PRESSURE BUILDS DOWN FROM THE NORTHWEST. BEST LIFT WILL RUN FROM
SOUTHWEST TO NORTHEAST ALONG BOUNDARY AS IT SHIFTS FARTHER SOUTH
THROUGH THE DAY. THEREFORE THE GREATEST POPS WILL BE IN THE
MORNING...FAIRLY WIDESPREAD ACROSS MUCH OF THE AREA AND THEN
DIMINISHING THROUGH THE AFTERNOON AS DIGGING MID TO UPPER TROUGH
AND HIGH PRESSURE PUSH FRONT SOUTHWARD. EXPECT A COOL RAIN AS
TEMPS DROP FROM MID 40S IN THE MORNING DOWN TO 30S BY AFTN. LATEST
SOUNDINGS KEEP SATURATED COLUMN ABOVE FREEZING UNTIL MON AFTN INTO
EARLY EVE. ONCE COLUMN GOES BELOW FREEZING IT DRIES OUT...LEAVING
ONLY A THIN SATURATED LAYER BETWEEN 6 TO 7 K FT AFTER 00Z ON NAM
SOUNDING. THEREFORE WILL FOLLOW PREVIOUS FORECAST KEEPING POPS OUT
OF FORECAST ONCE FZN PCP IS POSSIBLE LATE MONDAY.
COASTAL CAROLINAS WILL REMAIN AT THE BASE OF A VERY BROAD UPPER
TROUGH THROUGH REMAINDER OF THE PERIOD AS COOL SFC HIGH EXTENDS
DOWN FROM THE NORTH. FRONT WILL LINGER FROM SW TO NE SOUTH OF
FORECAST AREA WITH COOL AIR LOCKED IN PLACE MON NIGHT THROUGH
TUES. TEMPS MONDAY NIGHT WILL FALL INTO THE 20S IN PLENTY OF CAA.
TEMPS AT H85 DROP FROM AROUND 7 C MON MORNING DOWN TO -3C BY TUES
MORNING. MODELS CONTINUE TO SHOW A PERTURBATION MOVING ACROSS THE
CAROLINAS WITH ANOTHER WAVE OF LOW PRESSURE RIDING ALONG THE
FRONT OVERNIGHT MONDAY INTO TUES AS THE FRONT STARTS LIFTING NORTH.
NAM IS MOST AGGRESSIVE IN BRINGING MOISTURE AND LIFT NORTH EARLY
IN THE DAY ON TUES. FOR NOW HAVE INCLUDED SLIGHT CHC UP THROUGH
PORTIONS OF FLORENCE ACROSS TO THE GRAND STRAND AND SOUTH
INITIALLY AND SPREAD NORTH REMAINING ALIGNED MORE ALONG THE COAST
LATER ON TUES. HAVE INCLUDED SOME MIXED PCP AS SOUNDINGS REMAIN
BELOW ZERO UP THROUGH THE COLUMN MON NIGHT INTO EARLY TUES WITH A
WARM NOSE DEVELOPING INTO THE DAY BUT COLD TEMPS HOLDING ON. AS
FRONT TRIES TO MOVE NORTH EXPECT PCP TO SPREAD FARTHER NORTH ON
TUES. SHOULD GET PUSHED SOUTH AND EAST AS ANOTHER FRONT MOVES IN
FROM THE WEST BY WED MORNING. TEMPS SHOULD REMAIN COOL THROUGH THE
PERIOD.
&&
.LONG TERM /WEDNESDAY THROUGH SUNDAY/...
AS OF 300 PM SUNDAY...LARGE...BUT NOT EXCEPTIONALLY DEEP...TROUGH
WILL PERSIST ACROSS THE EAST INTO THE UPCOMING WEEKEND MAINTAIN
COLD AND UNSETTLED CONDITIONS FOR MUCH OF THE EXTENDED.
COLD FRONT STALLED WELL SOUTH OF THE AREA WILL SERVE AS THE
BAROCLINIC GRADIENT ALONG WHICH AN ACTIVE SOUTHERN STREAM WILL SPAWN
SEVERAL WAVES OF LOW PRESSURE. WHILE NONE OF THESE WILL BE
IMPRESSIVELY STRONG...EACH ONE WILL BRING AT LEAST A CHANCE OF
PRECIP TO THE AREA. TWO QUESTIONS WILL SURROUND EACH PASSING WAVE OF
LOW PRESSURE HOWEVER...HOW MUCH PRECIP WILL EXTEND NORTH FROM THE
LOW...AND WHETHER COLD ENOUGH AIR WILL BE IN PLACE FOR MIXED P-TYPE.
THE FIRST OF THESE...WEDNESDAY NIGHT AND THURSDAY...LOOKS NOW TO BE
THE MOST SIGNIFICANT OF THE WEEK. GUIDANCE IS TRACKING THIS SURFACE
LOW A LITTLE FURTHER WEST THAN PREVIOUS RUNS...AND THUS SLINGING
MORE PRECIP INTO THE CAROLINAS. ADMITTEDLY...THE E-W ORIENTED
BAROCLINIC ZONE DOES NOT`T SUPPORT A VERY FAR WEST TRACK AND WILL LEAN
MORE ON THE DRIER GFS...BUT WIDESPREAD CLOUDS WITH PERIODS OF PRECIP
ARE POSSIBLE WEDNESDAY NIGHT INTO THURSDAY. WITH COLD HIGH PRESSURE
IN PLACE RAIN COULD MIX WITH SOME FREEZING/FROZEN PRECIP...EVEN
THOUGH RAIN IS EXPECTED TO BE THE PRIMARY P-TYPE. THE ECMWF...WHICH
IS MORE ROBUST WITH ITS PRECIP...IS ALSO COLDER...BUT EVEN THE GFS
DEPICTS A PERIOD OF MIXED PRECIP. LOCAL TOP-DOWN METHODOLOGY
PRODUCES PRIMARILY RAIN AS EXPECTED...BUT HAVE LEFT A PERIOD OF MIX
PRECIP...RAIN AND SNOW WITH SNOW ONLY FAR NW...LATE WED NIGHT. QPF
WILL BE LIGHT AND POP IS LOW...BUT SNOWFLAKES ARE POSSIBLE WED NIGHT
BEFORE TEMPS WARM TO SUPPORT ONLY RAIN DURING THURSDAY.
A PERIOD OF DRIER WEATHER IS EXPECTED LATE THURSDAY INTO
FRIDAY...BEFORE ANOTHER LOW PRESSURE MOVES ALONG THE STALLED
BOUNDARY TO THE SOUTH. HOWEVER...EVEN DURING THIS "DRIER" PERIOD A
SCHC POP REMAINS WARRANTED DUE TO WAVES OF LOW PRESSURE ALONG THE
OFFSHORE BAROCLINIC GRADIENT - AND THERE IS LOW CONFIDENCE IN THE
TIMING/TRACK OF THESE FEATURES. THE PAST FEW DAYS...ECMWF/GFS HAD
SHOWN GOOD AGREEMENT IN BRINGING MORE SIGNIFICANT PRECIP LOCALLY
FRIDAY INTO SATURDAY...MUCH OF WHICH WOULD BE OF THE
FREEZING-TO-LIQUID TRANSITION VARIETY. TODAY...GUIDANCE HAS BACKED
OFF CONSIDERABLY...WHICH MAY MAKE SENSE DUE TO THE EXPECTED QUICK
E/NE TRACK OF SURFACE FEATURES. STILL...AM INCLINED TO MAKE ONLY
MINIMAL CHANGES TO THE FRI/SAT TIMEFRAME AS THIS REPRESENTS A NEW
SOLUTION...AND WILL LEAVE LOW MENTIONABLE POP WITH MIXED P-TYPE.
BY SUNDAY THE LONGWAVE TROUGH WILL BEGIN TO
ERODE...FINALLY...BRINGING BRIGHTER WEATHER AND MORE SEASONABLE
TEMPERATURES AFTER THE FIRST 4 DAYS OF THE EXTENDED CONTINUE WELL
BELOW NORMAL.
&&
.AVIATION /03Z MONDAY THROUGH FRIDAY/...
AS OF 00Z...PCPN COMING TO AN END ACROSS THE INLAND TERMINALS
WITHIN THE NEXT HOUR AND ACROSS THE SC COASTAL TERMINALS WILL
LEAVE PCPN TEMPO GROUP FOR ILM AS WE CAN STILL SEE SOME PCPN
DURING THE NEXT FEW HOURS. MOST OF THE STEADY MODERATE RAIN WILL
FALL BETWEEN THE COASTAL TERMINALS AND THE INLAND TERMINALS. WE
WILL SEE A LULL IN THE ACTIVITY FOR A FEW HOURS BEFORE THE NEXT
ROUND OF PCPN STARTS TO MOVE IN/FILL IN ACROSS THE RADAR AS A COLD
FRONT DROPS TO THE SE ACROSS THE CWA. WEAK AREA OF LOW PRESSURE TO
RIDE UP ALONG THIS FRONTAL BOUNDARY AND WILL SPREAD A LIGHT TO
MODERATE STEADY RAIN ACROSS THE TERMINALS AFTER 04Z THROUGH ABOUT
18Z-21Z. WILL FORECAST IFR ACROSS THE TERMINALS OVERNIGHT IN
VSBY/CEILINGS AND COULD POSSIBLY SEE LIFR. AS THE FRONT MOVES
ACROSS THE AREA THE PRESSURE GRADIENT WILL TIGHTEN UP DURING THE
DAY AND WINDS WILL INCREASE AND BE GUSTY FROM THE NORTH-NORTH
NORTHEAST WITH GUST AS HIGH AS 30KTS IN THE AFTERNOON. CONDITIONS
WILL START TO IMPROVE IN REGARDS TO VSBY/CEILING TOWARDS THE END
OF THE PERIOD...BUT TERMINALS WILL STILL BE IN MVFR AT BEST.
EXTENDED OUTLOOK...UNSETTLED WEATHER IS EXPECTED THROUGH THE
EXTENDED...WITH POSSIBLE IFR/MFR CONDITIONS AND SEVERAL CHANCES FOR
PRECIPITATION.
&&
.MARINE...
.NEAR TERM /THROUGH TONIGHT/...
AS OF 930 PM SUNDAY...WINDS ARE RELATIVELY LIGHT OVER THE WATERS
WITH SEAS RANGING FROM 2 TO 4 FEET. FRYING PAN SHOALS IS NOW
REPORTING SEAS DOWN TO 5 FEET JUST OUTSIDE THE COASTAL WATERS. A
LIGHT RAIN IS EXPECTED OVERNIGHT AS A COLD FRONT SLOWLY
APPROACHES THE WATERS BY DAYBREAK.
SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/...
AS OF 330 PM SUNDAY...SMALL CRAFT ISSUED FOR MONDAY THROUGH EARLY
TUES AS ARCTIC HIGH PRESSURE BUILDS DOWN BEHIND COLD FRONT. THIS
COLD FRONT WILL LINGER SOUTH OF AREA KEEPING TIGHTENED GRADIENT
FLOW THROUGH MON NIGHT AND ALONG WITH PLENTY OF CAA...WINDS AND
SEAS WILL RAMP UP TO 5 TO 7 FT IN STRONG NORTHERLY FLOW UP AROUND
25 KTS IN OUTER WATERS. THE STRONG N TO OFF SHORE COMPONENT WILL
KEEP HIGHEST SEAS AWAY FROM SHORE. WINDS START DECREASING TUE AS
ELONGATED SURFACE RIDGE AXIS MOVES TO THE COAST AND GRADIENT
RELAXES. LIGHT WINDS LATE TUE CONTINUE TUE NIGHT AS THE WEAK HIGH
EXITS NORTHEAST AND WINDS BACK TO WEST-SOUTHWEST. SEAS FALL TO 3
TO 5 FT LATER TUE AND 2 TO 4 FT TUE NIGHT.
LONG TERM /WEDNESDAY THROUGH FRIDAY/...
AS OF 300 PM SUNDAY...DIFFUSE PRESSURE PATTERN WEDNESDAY LEAVES A
WEAK GRADIENT AND LIGHT W-NW WINDS ACROSS THE WATERS. THIS WILL
CHANGE RAPIDLY WEDNESDAY NIGHT AND INTO THURSDAY AS A LOW PRESSURE
SYSTEM MOVES SE OF THE WATERS. THE LOW TRACK WILL REMAIN OUTSIDE THE
COASTAL WATERS...BUT THE GRADIENT AROUND THIS LOW WILL CAUSE NE
WINDS TO INCREASE STEADILY...BECOMING 15-20 KTS EARLY THURSDAY. AS
THE LOW PULLS AWAY THURSDAY NIGHT...THE GRADIENT WILL REMAIN PINCHED
THANKS TO A STALLED COLD FRONT SOUTH OF THE AREA...ALONG WHICH
ANOTHER LOW PRESSURE WILL DEVELOP AND MOVE OFF THE COAST FRIDAY.
THIS CONTINUES THE NE WINDS AT 15-20 KTS THROUGH THE END OF THE
PERIOD. SEAS WEDNESDAY WILL BE JUST 1-3 FT ON THE LIGHT AND VARIABLE
WINDS...BUT WILL INCREASE QUICKLY WED NIGHT ON THE INCREASING NE
FETCH. WAVE HEIGHTS BUILD TO 4-6 FT THURSDAY MORNING...AND THEN EVEN
A LITTLE HIGHER ON FRIDAY...AND AN EXTENDED SMALL CRAFT ADVISORY
WILL LIKELY BE NEEDED FOR MOST OF THURSDAY AND FRIDAY.
&&
.ILM WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
NC...NONE.
MARINE...SMALL CRAFT ADVISORY FROM 8 AM MONDAY TO 2 PM EST TUESDAY FOR
AMZ250-252-254-256.
&&
$$
NEAR TERM...HAWKINS
SHORT TERM...RGZ
LONG TERM...JDW
AVIATION...MAC
AREA FORECAST DISCUSSION
NWS NEWPORT/MOREHEAD CITY NC
400 PM EST SAT FEB 21 2015
.SYNOPSIS...
A COLD FRONT WILL APPROACH FROM THE WEST TONIGHT AND MOVE THROUGH
SUNDAY AFTERNOON AND EVENING. LOW PRESSURE WILL TRACK SOUTHEAST OF
THE AREA LATE SUNDAY NIGHT INTO MONDAY THEN HIGH PRESSURE WILL
PASS TO THE NORTH MONDAY NIGHT AND MOVE OFF THE COAST TUESDAY.
ANOTHER LOW PRESSURE AREA WILL PASS TO THE SOUTHEAST OF THE REGION
WEDNESDAY NIGHT INTO THURSDAY FOLLOWED BY HIGH PRESSURE BUILDING
INTO THE REGION FROM THE NORTH FRIDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 330 PM SAT...LATEST SFC ANALYSIS SHOWS WARM FRONT BISECTING
THE CWA FROM NORTH TO SOUTH...GENERALLY FROM OREGON INLET REGION
INTO THE COASTAL PLAIN NEAR ROCKY MOUNT.FRONT WILL CONTINUE TO
LIFT NORTHWARD THIS AFTERNOON AND EARLY EVENING...WITH SLY FLOW
DEVELOPING ACROSS ALL OF THE REGION. TEMPS WARMED VERY QUICKLY
THIS AFTERNOON ONCE WARM FRONT WENT THROUGH...WITH CURRENT TEMPS
PRED IN THE MID 50S ACROSS THE REGION...THOUGH HANGING TOUGH IN
THE LOW/MID 40S FOR THE ALBEMARLE SOUND REGION AND NORTHERN OUTER
BANKS. VERY MILD NIGHT EXPECTED...ESP COMPARED TO PAST SEVERAL
NIGHTS. EXPECT TO SEE NON- DIURNAL TEMP CURVE FOR MOST LOCATIONS
WITH LOWS IN THE LOW/UPPER 40S.
LATEST RADAR IMAGERY SHOWS AREA OF LIGHT SHOWERS TO THE
SOUTH...MOVING INTO THE SW CWA. TRENDED POPS BASED ON HRRR AND
NSSL WRF...WITH AREA OF SHOWERS MOVING INTO THE REGION THIS
EVENING...THEN MOVING OFF THE COAST AS ANOTHER AREA APPROACHES
FROM THE WEST EARLY SUNDAY MORNING. CAPPED POS AT HIGH CHANCE/LOW
LIKELY.
&&
.SHORT TERM /SUNDAY/...
AS OF 330 PM SAT...COLD FRONT WILL APPROACH FROM THE WEST
SUNDAY...MOVING THROUGH THE REGION LATE SUN AFTERNOON AND SUN
NIGHT. WILL MAINTAIN LIKELY POPS FOR MOST OF THE AREA SUN...WITH
SHOWERS TAPERING OFF FROM WEST TO EAST DURING THE AFTERNOON/EVENING.
WARM TEMPS EXPECTED AGAIN WITH LOW LEVEL THICKNESS VALUES AND SLY
FLOW SUPPORTING HIGHS IN THE MID 50S/LOW 60S.
&&
.LONG TERM /SUNDAY NIGHT THROUGH SATURDAY/...
AS OF 400 PM SATURDAY...TRICKY FORECAST AS TEMPERATURES WILL BE
MARGINAL FOR WINTRY WEATHER LATE SUNDAY NIGHT AND ESPECIALLY
MONDAY. THE COLD FRONT WILL CROSS THE AREA SUNDAY NIGHT AND SHOULD
BE JUST SOUTH OF THE AREA BY 12Z MONDAY. A WAVE IS THEN FORECAST
TO FORM ALONG THE FRONT AND MOVE EAST ALONG THE BOUNDARY BRINGING
WIDESPREAD RAIN TO THE AREA MAINLY AFTER MIDNIGHT SUNDAY NIGHT.
THE LOW LEVEL NORTHERLY FLOW WILL BE STRENGTHENING LATE SUNDAY
NIGHT AND MONDAY AND THIS PULL DOWN INCREASINGLY COLDER AIR INTO
THE REGION MONDAY CAUSING THE PRECIPITATION TO CHANGE FROM RAIN
TO FREEZING RAIN AND SLEET AND EVENTUALLY SNOW FROM NORTH TO
SOUTH. ALTHOUGH SIGNIFICANT PRECIPITATION IS EXPECTED MUCH OF IT
IS EXPECTED TO FALL AS RAIN WHICH WILL LIMIT THE IMPACTS OF WINTRY
PRECIPITATION ACROSS THE AREA. OTHER LIMITING FACTORS WILL BE THE
WARM GROUND AND THE SURFACE TEMPERATURES EXPECTED TO BE JUST ABOVE
FREEZING. THUS WILL NOT BE ISSUING ANY WATCHES OR ADVISORIES AT
THIS TIME. THE NAM AND GFS WERE COLDER THAN THE ECMWF AND
INDICATED MORE OF A THREAT WHILE THE CMC INDICATED MOSTLY RAIN
CHANGING OVER TO SLEET/SNOW AT THE END. THINK MOST OF IF NOT ALL
OF THE PRECIPITATION ENDS BEFORE 00Z TUESDAY.
THE FORECAST FOR THE REMAINDER OF THE PERIOD STILL IS BELOW NORMAL
CONFIDENCE BUT IT NOW APPEARS THAT TUESDAY SHOULD BE MAINLY DRY
WITH ONLY A SLIGHT CHANCE OF A SPRINKLE OR FLURRY. THE NEXT CHANCE
FOR SIGNIFICANT PRECIPITATION IS FORECAST LATE WEDNESDAY INTO
THURSDAY AS ANOTHER LOW TRACKS SOUTHEAST OF THE AREA. AGAIN WE
COULD SEE P TYPE ISSUES WITH THIS SYSTEM IF MOISTURE MATERIALIZES
WITH THIS SYSTEM. WILL INDICATE MAINLY DRY WEATHER FRIDAY AND THEN
COULD SEE RAIN DEVELOP ON SATURDAY POSSIBLY STARTING OUT AS
WINTRY MIX ESPECIALLY IF IT DEVELOPS FRIDAY NIGHT.
TEMPERATURES WILL CONTINUE THEIR TREND OF RUNNING BELOW NORMAL
DURING THE PERIOD.
&&
.AVIATION /20Z SATURDAY THROUGH THURSDAY/...
SHORT TERM /THROUGH 18Z SUNDAY/...
BKN/OVC STRATOCU WITH BASES 3500-4000 FT HAS MOVED IN OVER THE
AREA THIS AFTERNOON. EXPECT THAT CLOUD BASES WILL LOWER INTO THE
HIGH MVFR CATEGORY AS MOIST LOW LEVEL SOUTHERLY FLOW STRENGTHENS
THIS EVENING. ALSO SHORT RANGE MODELS ARE FAIRLY CONSISTENT IN
DEVELOPING A BAND OF SHOWERS ACRS THE COASTAL PLAIN THIS EVENING
AND MOVING IT TOWARD THE COAST EARLY SUNDAY MORNING WHICH WILL
REINFORCE MVFR CONDITIONS. EXPECT LOWERING CIGS/VSBYS INTO MAINLY
IFR CATEGORY LATE TONIGHT AS LOW LEVEL MOISTURE THICKENS IN A
WEAK NOCTURNAL INVERSION. LOW LEVEL MOISTURE WILL BE SLOW TO SCOUR
OUT AFTER SUNRISE SUNDAY BUT EXPECT CIGS RETURNING TO MVFR BY
MIDDAY TO EARLY AFTERNOON.
LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/...
AS OF 400 PM SATURDAY...LOOKING SUB VFR CONDITIONS THROUGH MONDAY
NIGHT DUE TO WIDESPREAD PRECIPITATION LATE SUNDAY NIGHT INTO
MONDAY AFTERNOON AND THE LIKELIHOOD THAT LOW CLOUDS PERSIST INTO
MONDAY NIGHT. EXPECTING DRIER WEATHER TUESDAY INTO WEDNESDAY WITH
VFR CONDITIONS THEN MORE PRECIPITATION IS EXPECTED LATE WEDNESDAY
INTO THURSDAY WITH SUB VFR CONDITIONS.
&&
.MARINE...
SHORT TERM /THROUGH SUNDAY/...
AS OF 330 PM SAT...LATEST OBS SHOW SE/S WINDS 10-20KT AND SEAS
2-4FT. WARM FRONT CONTINUES TO LIFT THROUGH THE ALBEMARLE SOUND
AND NORTHERN WATERS THIS AFTERNOON...WITH SLY WINDS GRADUALLY
INCREASING. PRESSURE GRADIENT TIGHTENS QUICKLY THIS AFTERNOON AND
TONIGHT WITH WARM FRONT TO THE NORTH AND APPROACHING COLD FRONT TO
THE WEST. SLY WINDS WILL INCREASE TO 15-25KT WITH SEAS BUILDING TO
5-9FT. SCA HEADLINES CONTINUE FOR THE PAMLICO SOUND AND COASTAL
WATERS. WINDS GRADUALLY DIMINISHING THROUGH THE DAY SUN...BY SUN
AFTERNOON EXPECT SW WINDS 10-15KT THOUGH EXPECTED ELEVATED SEAS TO
HANG TOUGH THROUGH THE PERIOD.
LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/...
AS OF 400 PM SATURDAY...EXPECTING HAZARDOUS CONDITIONS TO PREVAIL
THROUGH MUCH OF THE PERIOD. STRONG NORTHERLY WINDS 20 TO 30 KT ARE
FORECAST FROM SUNDAY NIGHT THROUGH MONDAY AS LOW PRESSURE TRACKS
SOUTHEAST OF THE WATERS. COULD EVEN SEE A PERIOD OF GALES.
CONDITIONS WILL GRADUALLY IMPROVE TUESDAY WITH CONDITIONS BRIEFLY
DROPPING BELOW ADVISORY LEVELS TUESDAY NIGHT AND WEDNESDAY.
ANOTHER LOW IS FORECAST TO MOVE SOUTHEAST OF THE WATERS WEDNESDAY
NIGHT INTO THURSDAY WITH A RETURN TO ADVISORY CONDITIONS
EXPECTED.
&&
.MHX WATCHES/WARNINGS/ADVISORIES...
NC...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 8 AM EST SUNDAY FOR AMZ135.
SMALL CRAFT ADVISORY UNTIL 1 PM EST TUESDAY FOR AMZ152-154.
SMALL CRAFT ADVISORY UNTIL 7 AM EST TUESDAY FOR AMZ150-156-158.
&&
$$
SYNOPSIS...CQD/HSA
NEAR TERM...CQD
SHORT TERM...CQD
LONG TERM...JME
AVIATION...JME/BTC
MARINE...JME/CQD
AREA FORECAST DISCUSSION...COR SYN
NWS WILMINGTON NC
349 PM EST SAT FEB 21 2015
.SYNOPSIS...
HIGH PRESSURE OFFSHORE WILL CIRCULATE MILD AIR INTO THE REGION
WITH TEMPERATURES IN THE 60S SUNDAY. A GOOD CHANCE OF SIGNIFICANT
RAIN IS EXPECTED SUNDAY NIGHT AND MONDAY...AS GULF MOISTURE IS LIFTED
AHEAD OF AN UPPER TROUGH MOVING ACROSS THE EAST COAST. COLD AIR WILL
RETURN LATE MONDAY AS ARCTIC HIGH PRESSURE BUILDS IN. COLD AND
UNSETTLED WEATHER IS EXPECTED MUCH OF THE UPCOMING WEEK AS CHILLY
HIGH PRESSURE AND GULF MOISTURE INTERACT.
&&
.NEAR TERM /UNTIL 6 AM SUNDAY MORNING/...
AS OF 345 PM SATURDAY...FORECAST ON TRACK FOR A WARMING AND
MOISTENING OF COLUMN THROUGH TONIGHT. TEMPS MADE IT UP INTO THE 50S
MOST PLACES IN WAA IN INCREASING SE TO S LOW LEVEL WINDS. 850 TEMPS
RISING FROM NEAR 0C THIS MORNING UP CLOSE TO 10C BY SUN MORNING IN
ENHANCED RETURN FLOW AROUND HIGH PRESSURE AS IT SHIFTS FARTHER OFF
SHORE. CLOUD COVER ASSOCIATED WITH CONVERGENCE ALONG COASTAL TROUGH
THROUGH THE GRAND STRAND INTO WESTERN PORTIONS OF FORECAST AREA
SPREADING NORTH REACHING ALL OF FORECAST AREA EARLY THIS AFTERNOON
AS COASTAL TROUGH/WARM FRONT SHIFTS NORTH THROUGH THIS EVENING.
COASTAL TROUGH QUITE EVIDENT IN OBS AND HIGHER RES MODELS WILL JOIN
WITH WARM FRONT INLAND BLOWING NORTH THROUGH TONIGHT. LOOKS LIKE
SOME LOW LEVEL CONVERGENCE AROUND RIDGE ALONG COASTAL TROUGH WILL
CONTINUE TO BE FOCUS FOR CLOUDS AND PCP INTO THIS EVENING.
LIFT WILL ALSO BE ENHANCED BY MINOR PERTURBATION PROGGED TO RIDE
THROUGH EASTERN CAROLINAS THIS EVENING...INCREASING CHC OF SHOWERS
MAINLY CLOSER TO THE COAST. ONCE THIS MOVES OFF SHORE AFTER
MIDNIGHT...LOCAL AREA WILL REMAIN IN DEEP WARM AND MOIST S-SW
FLOW...BUT SHOULD REMAIN BETWEEN SHWR ACTIVITY TO THE EAST OVER
WATERS AND WELL WEST...ASSOCIATED WITH APPROACHING COLD FRONT. MAY
EVEN END UP WITH SOME BREAKS IN CLOUD COVER OVERNIGHT. INCLUDED FOG
AND SEA FOG AS WARM MOIST AIR RIDES ADVECTS OVER COLD WATERS AND
OVER LAND. TEMPS OVERNIGHT WILL REMAIN WARM WITH MID 40S INLAND AND
NEAR 50 CLOSER TO THE COAST.
&&
.SHORT TERM /6 AM SUNDAY MORNING THROUGH MONDAY NIGHT/...
AS OF 3 PM SATURDAY...PRIMARY WEATHER HEADLINES SUNDAY AND MONDAY
ARE PROSPECTS OF A DECENT SOAKER OF A RAIN EVENT SUNDAY NIGHT TO
MONDAY MORNING...FOLLOWED BY A VERY SLIGHT CHANCE OF A FEW SNOW
FLURRIES LATE ON MONDAY.
GULF OF MEXICO TAP TO PLAY A NOTABLE ROLE IN ELEVATING DEEP COLUMN
MOISTURE 18Z SUN-00Z TUE...WITH STORM TOTAL CALCULATIONS PROGGING
ABOUT AN INCH OF RAINFALL ACROSS NE SC AND SE NC. THE BULK OF THIS
APT TO FALL AS 6Z-18Z MONDAY AS INSENTROPIC OMEGA INCREASES.
STRONG COLD AIR ADVECTION MONDAY AS HIGH PRESSURE OF ARCTIC BIRTH
BARGES IN...WITH DIURNAL TEMPERATURE RANGES NARROW IN THE BATTLE
WITH DAYTIME WARMING. VERY COLD AIR LATER IN THE DAY MONDAY AND
NIGHT ON THE HEELS OF EGRESSING MOISTURE...COULD OPEN A WINDOW
OF BRIEF SNOW FLURRIES. DEEP COLD CONVECTION UNLIKELY SINCE DRY
AIR ENCROACHMENT ABOVE 850 MB WILL ALREADY BE UNDERWAY.
MILDEST PERIOD SUNDAY AFTERNOON WITH 60S WIDESPREAD AWAY FROM THE
IMMEDIATE BEACHES. COLDEST PERIOD EARLY TUES AS ARCTIC AIR SPILLS
INTO THE CAROLINAS...MINIMUMS DAYBREAK TUESDAY 24-31 DEGREES.
&&
.LONG TERM /TUESDAY THROUGH SATURDAY/...
AS OF 345 PM SATURDAY...SUBTLE PATTERN SHIFT THROUGH THE EXTENDED
WILL LEAD TO CONTINUED COLD AIR ENTRENCHED ACROSS THE EAST...WITH
THE SOUTHERN STREAM BECOMING THE DOMINANT WEATHER MAKER THROUGH THE
WEEK.
LONG-WAVE TROUGH WHICH HAS PLAGUED THE EASTERN CONUS FOR THE PAST
MONTH WILL REMAIN...BUT IN A LESS AMPLIFIED SETUP. THE TROUGH WILL
BROADEN SUCH THAT IT EXTENDS WELL INTO THE ATLANTIC...AND WHILE THIS
WILL DO LITTLE TO REMEDY THE COLD...IT WILL KEEP MOST OF THE
PRECIPITATION SUPPRESSED TO THE SOUTH. COLD FRONT WILL BE STALLED
WELL SOUTH OF THE AREA TUESDAY MORNING...AND ALONG THIS BAROCLINIC
GRADIENT IS WHERE A SERIES OF SHORTWAVES AND WEAK LOW PRESSURES WILL
ROTATE THROUGH THE WEEK. THIS KEEPS AT LEAST A SCHC OF
PRECIP...ESPECIALLY SE ZONES...THROUGH THE WEEK. TIMING OF THESE
INDIVIDUAL SHORTWAVES AND SURFACE REFLECTIONS IS DIFFICULT...SO WILL
MAKE LITTLE CHANGE TO INHERITED POP...AND KEEP A SCHC OF PRECIP
ALONG THE COAST/SOUTH THROUGH THE WEEK. LOCAL TOP-DOWN METHODOLOGY
DOES PRODUCE PERIODS OF R/S OR R/IP/ZR...PRETTY MUCH EACH DAY.
CONFIDENCE IS LOW IN TIMING...AND TEMPS WILL WARM ABOVE FREEZING
EACH AFTN SO HAVE OPTED TO KEEP ONLY LIQUID PRECIP FOR NOW THROUGH
THURSDAY. HOWEVER...NEED TO MENTION THAT THERE VERY WELL COULD BE
PERIODS OF WINTRY MIXED PRECIP...ALMOST ANY DAY THROUGH THE WEEK.
TEMPS TUE-FRI WILL REMAIN WELL BELOW NORMAL FOR THE
PERIOD...AVERAGING ABOUT 10 DEGREES BELOW CLIMO.
LATE IN THE PERIOD THINGS GET A LITTLE MORE INTERESTING AS A STRONG
SURFACE WEDGE RE-BUILDS DOWN THE COAST AHEAD OF A MORE SIGNIFICANT
LOW PRESSURE SYSTEM. GUIDANCE AGREES THAT A COASTAL TROUGH WILL
SHARPEN AND CLOSE OFF ON SATURDAY...BUT THE INTENSITY AND TRACK OF
THE LOW IS STILL VERY MUCH IN QUESTION. WITH THE STRONG COLD WEDGE
IN PLACE...WE COULD BE LOOKING AT A MIXED P-TYPE EVENT FRIDAY NIGHT
INTO SATURDAY...BUT GUIDANCE DOES SHOW A QUICK WARMUP SATURDAY WHICH
WOULD TRANSITION TO ALL RAIN. LOTS OF UNCERTAINTY AT THIS TIME
RANGE...BUT THIS CONTINUES TO BE SUPPORTED BY GUIDANCE REGARDLESS OF
THE STRICT PATTERN EVOLUTION. WITH TEMPS BELOW FREEZING AND CHC POP
WARRANTED...AFTER COLLABORATION WITH NEIGHBORS HAVE OPTED TO INCLUDE
THE ZR CREATED FROM TOP-DOWN FOR FRIDAY NIGHT INTO SATURDAY. STILL A
LOT CAN CHANGE...BUT FRIDAY NIGHT INTO SATURDAY COULD GET MESSY
ACROSS THE AREA.
&&
.AVIATION /21Z SATURDAY THROUGH THURSDAY/...
AS OF 21Z...SE WINDS ARE EXPECTED THIS AFTERNOON. AS COASTAL
TROUGH PUSHES INLAND. ONLY MODERATE CONFIDENCE IN THE TIMING AND
COVERAGE OF PRECIPITATION THIS AFTERNOON...INTO THE EVENING AND
OVERNIGHT HOURS. THE HRRR AND THE NAM ARE IN REASONABLE AGREEMENT
WITH A CONVERGENCE BOUNDARY OVER THE MYRTLES...REACHING ILM BY
20-22Z. MVFR CONDITIONS ARE EXPECTED IN THIS REGION...WITH
POSSIBLE IFR CONDITIONS INLAND AS WARM SOUTHWEST FLOW RIDES OVER
RELATIVELY COOLER SURFACE TEMPS.
SUNDAY...LIGHT PRECIP WILL MOVE INTO THE WESTERN TERMINALS AS A COLD
FRONT APPROACHES FROM THE WEST. THERE IS SOME DISAGREEMENT AMONG
THE MODELS WITH RESPECT TO CEILINGS. WILL STAY RATHER PESSIMISTIC
AT THIS TIME...KEEPING IFR INLAND.
EXTENDED OUTLOOK...A SERIES OF WEAK SYSTEMS WILL MOVE THROUGH THE
REGION THROUGH THE FORECAST PERIOD...WITH PERIODS OF LIGHT PRECIP
POSSIBLE EACH DAY.
&&
.MARINE...
NEAR TERM /THROUGH TONIGHT/...
AS OF 345 PM FRIDAY...COASTAL TROUGH/WARM FRONT PROGRESSING INLAND
THIS AFTERNOON LEAVING ON SHORE SOUTHEAST WINDS OVER THE WATERS. A
PINCHED GRADIENT FROM COASTAL TROUGH WILL CONTINUE TO TIGHTEN
BETWEEN HIGH PRESSURE OFF SHORE AND FRONTAL SYSTEM OVER THE
CAROLINAS TO PRODUCE INCREASING WINDS THROUGH TONIGHT. WINDS WILL
VEER FROM SE TO S ONCE THIS COASTAL TROUGH/WARM FRONT BLOWS NORTH OF
THE AREA WATERS THROUGH TONIGHT. THE WARM AIR RUSHING OVER THE
COOLER SHELF WATERS WILL KEEP MARINE LAYER MORE STABLE WITH STRONGER
WINDS NOT MAKING IT DOWN TO WATER SFC CLOSER TO SHORE BUT AS YOU GO
FARTHER OFF SHORE...SOUTHERLY WINDS WILL BE STRONGER AND GUSTIER
PRODUCING CHOPPY AND HIGHER SEAS. OUTER WATERS WILL BE UP TO 5 TO 6
FT THROUGH TONIGHT. FRYING PAN BUOY MADE IT UP TO 7 FT THIS AFTN AND
THEREFORE KEPT 6 FT ALONG OUTER FRINGE OF 20 NM MARK ALL WATERS UP
UNTIL DAY BREAK AND INCLUDED FOR NORTHERN WATERS UP UNTIL 10 AM.
HAVE ALSO INCLUDED SOME SEA FOG IN CONTINUED WAA.
SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/...
AS OF 3 PM SATURDAY...ADVISORIES MAY BE NEEDED EARLY SUNDAY AS
SEA HEIGHTS RECOVER FROM THE PRESENT SE WAVE-BUILDING FETCH. AN
ADVISORY WILL AGAIN BE NEEDED MOST IF NOT ALL OF MONDAY AS NORTH
WINDS RIP ACROSS THE WATERS...DUE TO AN ARCTIC HIGH TAKEOVER.
A WAVE DIRECTION TRANSITION TO BISECT THIS TIME PERIOD AS S WAVE
ENERGY TURNS TO N AND NE MONDAY AND BUILDS WAVE-HEIGHTS AT TO
ABOVE ADVISORY RANGE IN TANDEM WITH ADVISORY WINDS TO BOOT. NO
TSTMS EXPECTED BUT PATCHY FOG WILL PLAGUE THE WATERS EARLY SUNDAY.
LONG TERM /TUESDAY THROUGH THURSDAY/...
AS OF 345 PM SATURDAY...COLD FRONT WILL REMAIN STALLED JUST SOUTH OF
THE WATERS THROUGH THE EXTENDED...WHILE WAVES OF LOW PRESSURE MOVE
ALONG THIS BOUNDARY. THE PERIOD WILL BE BOOK-ENDED BY GUSTY N/NE
WINDS BOTH EARLY TUESDAY AND AGAIN LATE THURSDAY...AS THE GRADIENT
TIGHTENS NEAR LOW PRESSURE SYSTEMS MOVING WELL OFF THE COAST. SPEEDS
DURING THESE NE SURGES WILL BE AROUND 15-20 KTS. WINDS EASE AND BACK
TO THE NW TUESDAY NIGHT AND THROUGH WEDNESDAY AS HIGH PRESSURE
RIDGES TOWARDS THE WATERS FROM THE NW...BEFORE AGAIN INCREASING LATE
THURSDAY AS MENTIONED ABOVE. SEAS WILL BE 3-5 FT EARLY TUESDAY ON
THE GUSTY NE WINDS...BEFORE EASING LATE TO 2-3 FT AND REMAINING AT
THESE AMPLITUDES THROUGH WEDNESDAY NIGHT. AS THE WINDS RISE ON
THURSDAY...SEAS BUILD AGAIN QUICKLY...AND AN EXTENDED PERIOD OF SCA
CONDITIONS MAY DEVELOP BEGINNING THURSDAY.
&&
.ILM WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
NC...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 10 AM EST SUNDAY FOR AMZ250-252-254-
256.
&&
$$
SYNOPSIS...MJC
NEAR TERM...RGZ
SHORT TERM...MJC
LONG TERM...JDW
AVIATION...DL/RGZ
AREA FORECAST DISCUSSION
NWS RALEIGH NC
330 PM EST SAT FEB 21 2015
.SYNOPSIS...A COLD FRONT WILL APPROACH FROM THE WEST TONIGHT AS AN
UPPER LEVEL DISTURBANCE PASSES TO OUR NORTH. THE COLD FRONT WILL
SETTLE SOUTH THROUGH THE AREA LATE SUNDAY AND THEN PUSH OFF THE
SOUTHEAST COAST ON MONDAY.
&&
.NEAR TERM /THROUGH SUNDAY NIGHT/...
AS OF 330 PM SATURDAY...
THE SHORTWAVE TROUGH CURRENTLY APPROACHING THE MID-MISSISSIPPI
VALLEY REGION WILL LIFT THROUGH THE TENNESSEE AND OHIO VALLEYS
TONIGHT. AT THE SURFACE...A RIDGE OF HIGH PRESSURE OVER CENTRAL NC
WILL GIVE WAY TO SOUTHERLY FLOW AS THE ASSOCIATED COLD FRONT
APPROACHES THE MOUNTAINS FROM THE WEST.
LIGHT SNOW IN THE TRIAD EARLIER THIS MORNING YIELDED NO REPORTED
ACCUMULATIONS AND HAS SINCE MOVED OFF TO THE NORTH. WARM ADVECTION
CONTINUES TO STRENGTHEN OVER THE REGION AS AN INTENSE LOW-LEVEL JET
(85KT AT BNA THIS MORNING) TRANSLATES EAST. TEMPERATURES HAVE BEEN
RISING MUCH MORE QUICKLY IN THE SOUTHEAST SINCE NOON AS THE FLOW HAS
BECOME SOUTHEASTERLY...REACHING THE MID-50S IN THE SANDHILLS AND
SOUTHERN COASTAL PLAIN. THERE IS ALSO SOME CLEARING ACROSS THE
SOUTHERN PIEDMONT...WHICH MATCHES AN AREA OF DRYING NOTED IN RAP RH
CROSS-SECTIONS. HOWEVER...MID AND HIGH LEVEL MOISTURE IS RAPIDLY
SPREADING IN FROM THE WEST AND MOSTLY CLOUDY SKIES WILL THE RULE FOR
MOST OF THE EVENING. THE FEW AREA OF WEAK RADAR ECHOES RACING
NORTH/NORTHEAST ACROSS THE PIEDMONT AND COASTAL PLAIN ARE NOT AS
ROBUST AS THE HI-RES MODELS HAD INDICATED...AT LEAST NOT SO
FAR...POSSIBLY DUE TO THE AFOREMENTIONED DRYING. WILL MAINTAIN A
SLIGHT CHANCE POP OF WHAT SHOULD BE RAIN FOR MOST AREAS AS THE
WETBULB FREEZING LINE CONTINUES TO RETREAT NORTHWEST WITH THE
WARMING/MOISTENING. THE EXCEPTION MAY BE THE NORTHERN PIEDMONT
WHERE A POCKET OF SLEET MAY BE POSSIBLE IF PRECIP IS HEAVY
ENOUGH...BUT CONFIDENCE IN THIS IS LOW AND THE IMPACTS WOULD BE NIL.
THE MAIN OVERNIGHT CONCERNS WILL BE THE TIMING OF A PREFRONTAL
RAINBAND ASSOCIATED WITH THE LOW-LEVEL JET AND ALSO THE POSSIBILITY
OF FOG/LOW CLOUDS PRECEDING THE RAIN. FORECAST SOUNDINGS ARE IN
GOOD AGREEMENT ON AT LEAST SOME STRATUS ASSOCIATED WITH THE STRONG
WARM ADVECTION AND RISING DEWPOINTS. HOWEVER...PERIOD OF DRY AIR IN
THE MID LEVELS MAY RESULT IN FOG EVEN DESPITE A STEADY SOUTHERLY
WIND. THE PRIMARY AREA OF RAIN SHOULD ENTER THE NORTHWEST PIEDMONT
SHORTLY AFTER MIDNIGHT AND TRANSLATE SOMEWHAT SLOWLY EAST THROUGH
THE AREA THROUGH MIDDAY ON SUNDAY. WITH THE MAIN UPPER FORCING
MOVING OFF TO THE NORTH AND THE LOW-LEVEL JET EXITING TO THE
NORTHEAST...RAINFALL INTENSITY SHOULD ACCORDINGLY DECREASE WITH TIME
SUNDAY MORNING. MODEL QPF SHOWS THIS TREND WITH A THIRD OF AN INCH
NORTHWEST TO AROUND A TENTH IN THE SOUTHEAST. THE ACTUAL FRONT
LOOKS TO BE DELAYED BY 3 TO 6 HOURS...FINALLY SETTLING SOUTH THROUGH
THE AREA IN THE 21Z TO 03Z TIME FRAME. BUT... IT DOESNT STOP THERE
AS MODELS SHOW A LOW-AMPLITUDE UPPER WAVE AND SPEED MAX TRANSLATING
ACROSS THE GULF COAST STATES SUNDAY NIGHT...WHICH BRINGS ANAFRONTAL
PRECIP BACK ACROSS AT LEAST THE SOUTHERN HALF OF NC AFTER MIDNIGHT
SUNDAY NIGHT. THE POST-FRONTAL COLD ADVECTION WILL BE PUSHING TEMPS
AND LOW-LEVEL THICKNESSES BACK DOWN TOWARD THE CRITICAL VALUES FOR
SOME WINTRY MIX...BUT IT CURRENTLY LOOKS LIKE THIS WILL HOLD OFF
UNTIL AFTER 12Z MONDAY (SEE MORE BELOW).
THE GENERAL TREND FOR (FINALLY) ABOVE FREEZING TEMPS WILL BE TO RISE
SLIGHTLY OR HOLD STEADY IN THE MID 30S NORTHWEST TO MID/UPPER 40S
SOUTHEAST. HIGHS SUNDAY IN THE UPPER 40S TO MID 50S...FALLING INTO
THE MID TO UPPER 30S MONDAY NIGHT.
&&
.SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/...
AS OF 250 AM SATURDAY...
SURFACE COLD FRONT WILL BE OFFSHORE MONDAY MORNING...WITH COLD HIGH
PRESSURE BUILDING EAST ACROSS THE OHIO VALLEY AND SPILLING DOWN THE
EAST COAST. THERE WILL BE A SMALL POTENTIAL FOR SOME LINGERING
ANAFRONTAL LIGHT RAIN IN THE EAST MONDAY MORNING AS THE TRAILING H85
TROF MOVES ACROSS THE AREA. OTHERWISE...WILL LIKELY SEE SOME
AFTERNOON SUN...ESPECIALLY ACROSS THE NORTHWEST...TO FEEBLY OFFSET
STRENGTHENING COLD AIR ADVECTION. HIGHS WILL STRUGGLE TO REACH 40
ACROSS THE NORTH...WITH LOWER 40S ACROSS THE SOUTHERN TIER...A GOOD
15 DEGREES BELOW NORMAL. AXIS OF THE SURFACE HIGH WILL BE ALIGNED
DOWN THE COAST MONDAY NIGHT...WITH MINS POTENTIALLY IN THE UPPER
TEENS ACROSS THE NORTHERN TIER TO LOW 20S SOUTH. HIGHS TUESDAY WILL
BE SIMILAR...PERHAPS EVEN A DEGREE OR TWO COOLER...THAN MONDAY UNDER
THE HIGH PRESSURE...MOSTLY IN THE UPPER 30S. SURFACE HIGH SHIFTING
OFFSHORE AND INCREASED MID CLOUDINESS AHEAD OF AN APPROACHING FRONT
TUESDAY NIGHT WILL SOFTEN THE DIURNAL CRASH A BIT...WITH MINS IN THE
LOW TO MID 20S.
&&
.LONG TERM /WEDNESDAY THROUGH FRIDAY/...
AS OF 250 AM SATURDAY...
...WELL BELOW NORMAL TEMPERATURES WILL CONTINUE INTO THE
WEEKEND...
UPPER PATTERN WILL TRANSITION TO FLATTER...NEAR ZONAL FLOW ALOFT AS
BROAD TROFFING SETS UP ACROSS THE NORTHERN CONUS THROUGH THE
REMAINDER OF THE WEEK. THIS WILL EFFECTIVELY SUPPRESS MOISTURE
TRANSPORT SOUTH ACROSS THE GULF STATES. IN THE ABSENCE OF
COMPLEMENTARY SYNOPTIC SIGNALS IN THE LATEST MODEL RUNS...THIS
PATTERN SUGGESTS MINIMAL PRECIP CHANCES THROUGH THE WEEK...AND WILL
MAINTAIN ONGOING DRY FORECAST. WE WILL HAVE A REINFORCING COLD FRONT
MOVE ACROSS ON WEDNESDAY...WITH BRIEF WARM AIR ADVECTION AHEAD OF
THE FRONT BUMPING HIGHS UP A BIT INTO THE MID 40S. BEHIND THE
FRONT...A SOUTHERN STREAM SHORT WAVE INDUCES CYCLOGENESIS ALONG THE
FRONTAL BOUNDARY ACROSS NORTHERN FLORIDA WEDNESDAY NIGHT...AND THE
LATEST ECMWF KEEPS THE LOW CLOSE ENOUGH TO THE COAST TO WRAP SOME
PRECIP BACK INTO EASTERN NC...BUT WILL NEED TO SEE LATER MODEL
CONSENSUS ON THIS SOLUTION BEFORE INTRODUCING POPS AT THIS POINT.
THE UPSHOT...COLDER AIR RETURNS FOR LATE WEEK...WITH HIGHS BOTH
THURSDAY AND FRIDAY IN THE UPPER 30S NORTH TO BARELY 40 ACROSS THE
SOUTHERN TIER AFTER MORNING LOWS MOSTLY FROM 20 TO 25.
&&
.AVIATION /18Z SATURDAY THROUGH THURSDAY/...
AS OF 105 PM SATURDAY...
MVFR CEILINGS ARE LIKELY TO CONTINUE FOR MUCH OF THE
AFTERNOON...THOUGH THERE IS SOME CLEARING ASSOCIATED WITH SOME DRIER
LOW/MID LEVEL AIR OVER SC THAT IS CURRENTLY WORKING NORTH TOWARD THE
SOUTHERN PIEDMONT. WHILE CONFIDENCE IS THE TIMING AND DURATION OF
IMPROVED AND POSSIBLY VFR CEILINGS IS LOW...WILL SHOW SOME
SCATTERING OF THE 1500-2500 FT CEILINGS CURRENTLY OBSERVED THROUGH
00Z. LATER THIS EVENING...CONTINUED WARM ADVECTION COMBINED WITH
DRIER AIR ABOVE THE SURFACE MAY LEAD TO SOME FOG....MAINLY PRIOR TO
MIDNIGHT BEFORE A BAND OF RAIN MOVES IN FROM THE NORTHWEST AHEAD OF
AN APPROACHING COLD FRONT. CEILINGS WILL REMAIN LOW AS THE RAIN
SPREADS ACROSS THE AREA...MOST LIKELY IN THE IFR RANGE. WINDS WILL
REMAIN OUT OF THE SOUTH-SOUTHWEST
OUTLOOK...THE COLD FRONT WILL SINK SOUTH THROUGH THE AREA LATE
SUNDAY. SUB-VFR CEILINGS MAY LINGER BEHIND THE FRONT AS PRECIP
SPREADS BACK ACROSS AT LEAST THE SOUTHERN PORTIONS OF NC LATER
SUNDAY NIGHT INTO MONDAY. VFR CONDITIONS WILL RETURN BY TUESDAY.
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...BLS
NEAR TERM...BLS
SHORT TERM...MLM
LONG TERM...MLM
AVIATION...BLS
AREA FORECAST DISCUSSION
NWS RALEIGH NC
105 PM EST SAT FEB 21 2015
.SYNOPSIS...FRIGID HIGH PRESSURE WILL RETREAT OFF THE MID-ATLANTIC
COAST TODAY. A COLD FRONT WILL APPROACH FROM THE WEST TONIGHT... AND
WILL MOVE THROUGH THE AREA ON SUNDAY.
&&
.NEAR TERM /SATURDAY THROUGH SUNDAY NIGHT/...
AS OF 1015 AM SATURDAY...
SHORTWAVE TROUGH OVER THE CENTRAL PLAIN/MID MS VALLEY THIS MORNING
WILL MOVE NEWD INTO THE OHIO VALLEY THIS AFTERNOON AND THEN INTO THE
NEW ENGLAND TONIGHT. ASSOCIATED SFC WAVE AND FRONTAL ZONE WILL
ADVANCE EAST INTO THE TN AND OHIO VALLEY TODAY...REACHING THE
CENTRAL AND SOUTHERN APPALACHIANS AOA 12Z SUNDAY.
MORNING UPDATE... RADAR ECHOES HAVE BEEN FILLING IN OVER THE FAR
NORTHWEST PIEDMONT SINCE 12Z...THOUGH THE REFLECTIVITY VALUES ARE
VERY WEAK AND KINT HAS ONLY REPORTED 9SM VISIBILITY THROUGHOUT THE
LIGHT SNOW....SUGGESTING THE SNOW IS VERY LIGHT. RAP MOISTURE
FIELDS SHOW A COUPLE MORE HOURS OF (NEAR) SATURATION ABOVE -10C AND
A SLIGHTLY HEAVIER AREA OF SNOW LOOKS POISED TO POSSIBLY CLIP THE
NORTHWESTERN HALF OF FORSYTH COUNTY. SO FAR THERE HAVE BEEN NO
REPORTS OF ACCUMULATION...THOUGH A DUSTING CERTAINLY SEEMS POSSIBLE.
HAVE ISSUED AN SPS TO HIGHLIGHT ANY LIGHT ACCUMULATION AND ISOLATED
TRAVEL CONCERN...BUT WITHOUT GREATER RATES THIS DOESN`T WARRANT AN
ADVISORY. DRYING IN THE MID-LEVELS CAUSE THE LIGHT SNOW TO
END...POSSIBLY AS SLEET ON THE TAIL END...AND THEN NEARLY ALL
GUIDANCE HAS THE WESTERN PIEDMONT DRY AFTER 18Z.
TO THE EAST...MOISTURE ADVECTION FROM OFF THE SC COAST IS RAMPING
UP...EVIDENT IN THE QUICK SURGE OF 2000-3000FT CEILINGS ACROSS THE
SOUTHERN COASTAL PLAIN. AT THE SURFACE...THE RIDGE OF HIGH PRESSURE
EXTENDING FROM THE OFF THE DELMARVA IS STILL HOLDING ON AND SURFACE
WINDS HAVE YET TO REALLY TURN TO SOUTHEASTERLY. WITH TEMPS
CURRENTLY IN THE UPPER 20S/ LOWER 30S AND DEWPOINTS STILL IN THE
TEENS...THE WETBULB FREEZING LINE IS STILL SUPPRESSED TO THE COAST.
HOWEVER... AS THE HIGH WEAKENS...WINDS ARE STILL FORECAST TO SHIFT
AND DEWPOINTS SHOULD THEN RISE MORE DRAMATICALLY....CAUSING THE
WETBULB FREEZING LINE TO QUICKLY RETREAT THROUGH THE PIEDMONT. HI-
RES MODELS AND MAINLY NAM/GFS INDICATED SOME SHOWERY TYPE PRECIP
BREAKING OUT ACROSS THE COASTAL PLAIN...BUT BY THEN WARMING WILL
KEEP EVERYTHING LIQUID. NO MAJOR CHANGES TO THE FORECAST FOR THE
EASTERN AREAS. HIGHS RANGING FROM THE MID 30S NORTHWEST TO AROUND
50 SOUTHEAST. -BLS
TONIGHT THROUGH SUNDAY NIGHT: RAIN CHANCES WILL INCREASE AFTER
MIDNIGHT AND INTO THE DAY ON SUNDAY OWING TO STRENGTHENING MOISTURE
CONVERGENCE WITH THE APPROACH OF THE FRONT INTO THE AREA. PWATS
INCREASE TO 1.0-1.25" WITH THE FRONT MOVING THROUGH THE AREA BETWEEN
12Z SUNDAY TO 00Z MONDAY. SOUNDINGS/THERMAL PROFILES SUPPORT ALL
LIQUID WITH A SOLID BAND OF RAIN ACCOMPANYING THE FRONT INTO THE
PIEDMONT BY THE MID TO LATE MORNING HOURS...THEN WEAKENING/FALLING
APART AS IT REACHES THE COASTAL PLAIN AS DEEPER MOISTURE EXITS
OFFSHORE WITH THE ATTENDANT LOW-LEVEL JET. RAIN CHANCES COULD LINGER
IN THE WAKE OF THE FRONT SUNDAY NIGHT AND INTO MONDAY ACROSS THE FAR
SOUTHERN ZONES AS THE H8 TROUGH IS SLOW TO CLEAR THE AREA. QPF
AMOUNTS RANGING FROM A TENTH IN THE EAST TO A HALF INCH ACROSS THE
WEST.
LOWS SUNDAY NIGHT IN THE LOWER TO MID 30S NW TO MID/UPPER SE. HIGHS
SUNDAY WILL DEPEND ON TIMING/COVERAGE OF PRECIP...RANGING FROM LOWER
50 NW TO UPPER 50S/NEAR 60 SE. CAA WILL GOVERN LOWS SUNDAY NIGHT...
RANGING FROM NEAR 30 NORTH TO UPPER 30S SOUTH.
&&
.SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/...
AS OF 250 AM SATURDAY...
SURFACE COLD FRONT WILL BE OFFSHORE MONDAY MORNING...WITH COLD HIGH
PRESSURE BUILDING EAST ACROSS THE OHIO VALLEY AND SPILLING DOWN THE
EAST COAST. THERE WILL BE A SMALL POTENTIAL FOR SOME LINGERING
ANAFRONTAL LIGHT RAIN IN THE EAST MONDAY MORNING AS THE TRAILING H85
TROF MOVES ACROSS THE AREA. OTHERWISE...WILL LIKELY SEE SOME
AFTERNOON SUN...ESPECIALLY ACROSS THE NORTHWEST...TO FEEBLY OFFSET
STRENGTHENING COLD AIR ADVECTION. HIGHS WILL STRUGGLE TO REACH 40
ACROSS THE NORTH...WITH LOWER 40S ACROSS THE SOUTHERN TIER...A GOOD
15 DEGREES BELOW NORMAL. AXIS OF THE SURFACE HIGH WILL BE ALIGNED
DOWN THE COAST MONDAY NIGHT...WITH MINS POTENTIALLY IN THE UPPER
TEENS ACROSS THE NORTHERN TIER TO LOW 20S SOUTH. HIGHS TUESDAY WILL
BE SIMILAR...PERHAPS EVEN A DEGREE OR TWO COOLER...THAN MONDAY UNDER
THE HIGH PRESSURE...MOSTLY IN THE UPPER 30S. SURFACE HIGH SHIFTING
OFFSHORE AND INCREASED MID CLOUDINESS AHEAD OF AN APPROACHING FRONT
TUESDAY NIGHT WILL SOFTEN THE DIURNAL CRASH A BIT...WITH MINS IN THE
LOW TO MID 20S.
&&
.LONG TERM /WEDNESDAY THROUGH FRIDAY/...
AS OF 250 AM SATURDAY...
...WELL BELOW NORMAL TEMPERATURES WILL CONTINUE INTO THE
WEEKEND...
UPPER PATTERN WILL TRANSITION TO FLATTER...NEAR ZONAL FLOW ALOFT AS
BROAD TROFFING SETS UP ACROSS THE NORTHERN CONUS THROUGH THE
REMAINDER OF THE WEEK. THIS WILL EFFECTIVELY SUPPRESS MOISTURE
TRANSPORT SOUTH ACROSS THE GULF STATES. IN THE ABSENCE OF
COMPLEMENTARY SYNOPTIC SIGNALS IN THE LATEST MODEL RUNS...THIS
PATTERN SUGGESTS MINIMAL PRECIP CHANCES THROUGH THE WEEK...AND WILL
MAINTAIN ONGOING DRY FORECAST. WE WILL HAVE A REINFORCING COLD FRONT
MOVE ACROSS ON WEDNESDAY...WITH BRIEF WARM AIR ADVECTION AHEAD OF
THE FRONT BUMPING HIGHS UP A BIT INTO THE MID 40S. BEHIND THE
FRONT...A SOUTHERN STREAM SHORT WAVE INDUCES CYCLOGENESIS ALONG THE
FRONTAL BOUNDARY ACROSS NORTHERN FLORIDA WEDNESDAY NIGHT...AND THE
LATEST ECMWF KEEPS THE LOW CLOSE ENOUGH TO THE COAST TO WRAP SOME
PRECIP BACK INTO EASTERN NC...BUT WILL NEED TO SEE LATER MODEL
CONSENSUS ON THIS SOLUTION BEFORE INTRODUCING POPS AT THIS POINT.
THE UPSHOT...COLDER AIR RETURNS FOR LATE WEEK...WITH HIGHS BOTH
THURSDAY AND FRIDAY IN THE UPPER 30S NORTH TO BARELY 40 ACROSS THE
SOUTHERN TIER AFTER MORNING LOWS MOSTLY FROM 20 TO 25.
&&
.AVIATION /18Z SATURDAY THROUGH THURSDAY/...
AS OF 105 PM SATURDAY...
MVFR CEILINGS ARE LIKELY TO CONTINUE FOR MUCH OF THE
AFTERNOON...THOUGH THERE IS SOME CLEARING ASSOCIATED WITH SOME DRIER
LOW/MID LEVEL AIR OVER SC THAT IS CURRENTLY WORKING NORTH TOWARD THE
SOUTHERN PIEDMONT. WHILE CONFIDENCE IS THE TIMING AND DURATION OF
IMPROVED AND POSSIBLY VFR CEILINGS IS LOW...WILL SHOW SOME
SCATTERING OF THE 1500-2500 FT CEILINGS CURRENTLY OBSERVED THROUGH
00Z. LATER THIS EVENING...CONTINUED WARM ADVECTION COMBINED WITH
DRIER AIR ABOVE THE SURFACE MAY LEAD TO SOME FOG....MAINLY PRIOR TO
MIDNIGHT BEFORE A BAND OF RAIN MOVES IN FROM THE NORTHWEST AHEAD OF
AN APPROACHING COLD FRONT. CEILINGS WILL REMAIN LOW AS THE RAIN
SPREADS ACROSS THE AREA...MOST LIKELY IN THE IFR RANGE. WINDS WILL
REMAIN OUT OF THE SOUTH-SOUTHWEST
OUTLOOK...THE COLD FRONT WILL SINK SOUTH THROUGH THE AREA LATE
SUNDAY. SUB-VFR CEILINGS MAY LINGER BEHIND THE FRONT AS PRECIP
SPREADS BACK ACROSS AT LEAST THE SOUTHERN PORTIONS OF NC LATER
SUNDAY NIGHT INTO MONDAY. VFR CONDITIONS WILL RETURN BY TUESDAY.
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...CBL
NEAR TERM...CBL/BLS
SHORT TERM...MLM
LONG TERM...MLM
AVIATION...BLS
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
1243 PM EST SAT FEB 21 2015
.SYNOPSIS...
SURFACE HIGH WILL PUSH FARTHER OFFSHORE TODAY WITH MILDER
TEMPERATURES AND INCREASING RAIN CHANCES INTO SUNDAY AS COASTAL
TROUGH MOVES NORTH AS WARM FRONT. A COLD FRONT WILL
FOLLOW...MOVING THROUGH THE CAROLINAS SUNDAY NIGHT...STALLING
ACROSS FLORIDA FOR THE REMAINDER OF NEXT WEEK. SEVERAL AREAS OF
LOW PRESSURE ALONG THE FRONT MAY BRING UNSETTLED CONDITIONS NEXT
WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 1200 PM SATURDAY...FORECAST ON TRACK FOR A WARMING AND
MOISTENING OF COLUMN THROUGH THE DAY. TEMPS ON THE RISE IN WAA IN INCREASING
SE TO S LOW LEVEL WINDS. 850 TEMPS RISING FROM NEAR 0C THIS
MORNING UP CLOSE TO 10C BY SUN MORNING IN ENHANCED RETURN FLOW AROUND
HIGH PRESSURE AS IT SHIFTS FARTHER OFF SHORE. CLOUD COVER
ASSOCIATED WITH CONVERGENCE ALONG COASTAL TROUGH THROUGH THE
GRAND STRAND INTO WESTERN PORTIONS OF FORECAST AREA SPREADING
NORTH REACHING ALL OF FORECAST AREA EARLY THIS AFTERNOON AS
COASTAL TROUGH/WARM FRONT SHIFTS NORTH THROUGH THE DAY. TEMPS
ACROSS SUNNIER SPOTS INCREASED A LITTLE FASTER THIS MORNING...BUT
WAA WILL BRING MOST TEMPS UP CLOSE TO 50 INLAND AND MID 50S CLOSER
TO THE COAST...BRINGING US OUT OF OUR COLD SNAP. RIGHT ALONG THE
BEACHES TEMPS WILL BE LEVEL OFF AND FEEL COOLER COOL ON SHORE FLOW
WITH COOLER OCEAN WATERS.
COASTAL TROUGH QUITE EVIDENT IN OBS AND HIGHER RES MODELS WILL
JOIN WITH WARM FRONT INLAND BLOWING NORTH THROUGH LATER TODAY INTO
TONIGHT. LOOKS LIKE SOME LOW LEVEL CONVERGENCE AROUND RIDGE ALONG
COASTAL TROUGH WILL CONTINUE TO BE FOCUS FOR CLOUDS AND PCP THIS
AFTERNOON. LIFT WILL ALSO BE ENHANCED BY MINOR PERTURBATION
PROGGED TO RIDE THROUGH EASTERN CAROLINAS THIS EVENING...WITH MORE
CLOUDS AND SHOWERS EXPECTED. ONCE THIS MOVES OFF SHORE AFTER
MIDNIGHT...LOCAL AREA WILL REMAIN IN DEEP WARM AND MOIST S-SW
FLOW...BUT SHOULD REMAIN BETWEEN SHWR ACTIVITY TO THE EAST OVER
WATERS AND WELL WEST...ASSOCIATED WITH APPROACHING COLD FRONT. MAY
EVEN END UP WITH SOME MAINLY CLEAR AREAS OVERNIGHT. MAY HAVE TO
EVALUATE FURTHER FOR POTENTIAL FOR FOG AND SEA FOG AS WARM MOIST
AIR RIDES ADVECTS OVER COLD WATERS AND OVER LAND. TEMPS OVERNIGHT
WILL REMAIN WARM WITH MID 40S INLAND AND NEAR 50 CLOSER TO THE
COAST.
&&
.SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/...
AS OF 3 AM SATURDAY...PERIOD BEGINS WITH WEAKLY FORCED COLD FRONT
POISED TO ENTER THE AREA. LINE OF SHOWERS AHEAD OF THE FRONT WILL BE
WEAKENING AS THEY REACH THE WESTERN EDGE OF THE FORECAST AREA. MID
LEVEL SUPPORT WILL BE WANING AS THE SHORTWAVE RESPONSIBLE FOR THE
ACTIVITY LIFTS OFF TO THE NORTHEAST. THERE WILL BE PLENTY OF
MOISTURE AVAILABLE AND STRONG WARM ADVECTION AHEAD OF THE FRONT
SHOULD PUSH TEMPS INTO THE 60S. THINK A BROKEN LINE OF SHOWERS WILL
MOVE ACROSS THE AREA DURING EARLY TO MID AFTERNOON WITH THE BEST
ACTIVITY/HIGHEST QPF ACROSS INLAND NC. MOST AREAS ARE LIKELY TO SEE
AT LEAST SOME MEASURABLE PRECIP THOUGH THINK TOTAL RAINFALL WILL BE
ON THE LOW END.
SECOND ROUND OF PRECIP SUN NIGHT LOOKING MORE LIKELY. LACK OF STRONG
MID LEVEL PUSH BEHIND THE FRONT LEAVES THE BOUNDARY STALLED CLOSE TO
THE COAST. WEAK SURFACE WAVE AND MID LEVEL INFLECTION COINCIDENT
WITH DEEP MOISTURE BRUSHES THE AREA AS IT LIFTS EAST-NORTHEAST SUN
NIGHT. ALTHOUGH ISENTROPIC LIFT IS NOT MAXIMIZED THERE IS A PERIOD
OF SOME ENHANCED LIFT ALONG WITH MID LEVEL DYNAMICS. INHERITED POP
FORECAST INCLUDES A SOUTHEAST(HIGH) TO NORTHWEST(LOW) POP GRADIENT
WHICH WILL BE MAINTAINED BUT WILL RAISE NUMBERS. PRECIP MAY LINGER
INTO MON MORNING...ESPECIALLY ALONG THE COAST...BUT BY MIDDAY
SUBSIDENCE IN THE WAKE OF THE EXITING SHORTWAVE ALONG WITH NEXT
ARCTIC HIGH BUILDING IN FROM THE NORTHWEST WILL BRING AN END TO
PRECIP IN THE REGION. AIR MASS IS NOT NEARLY AS COLD AS THE LAST FEW
AND WHILE TEMPS WILL DROP BELOW NORMAL MON AND MON NIGHT ANOTHER
EXTREME ARCTIC OUTBREAK DOES NOT LOOK TO BE IN THE CARDS.
&&
.LONG TERM /TUESDAY THROUGH FRIDAY/...
AS OF 3 AM SATURDAY...LONG TERM PERIOD WILL BE UNSETTLED WITH
ABUNDANT CLOUD COVER BUT LIMITED BOUTS OF MEASURABLE PRECIP. SURFACE
HIGH REMAINS IN PLACE TUE WITH WEAK SHORTWAVE AND SURFACE INFLECTION
PASSING OFF THE SOUTHEAST COAST. NOT EXPECTING A LOT OF PRECIP WITH
THE FEATURE AS IT PASSES TO THE SOUTH BUT CLOUD COVER IS LIKELY.
BRIEF PERIOD OF RETURN FLOW WED AHEAD OF NEXT COLD FRONT WILL HAVE
LIMITED SUCCESS IN WARMING TEMPS. WED SHOULD BE THE WARMEST DAY OF
THE PERIOD BUT HIGHS WILL STILL BE 10+ DEGREES BELOW CLIMO. FRONT
WILL BE IN THE PROCESS OF WASHING OUT AS IT REACHES THE AREA AND
DESPITE ABUNDANT MOISTURE THERE IS A NOTICEABLE LACK OF FORCING WITH
THE FRONT. CANNOT RULE OUT SOME ISOLATED SPRINKLES BUT MEASURABLE
RAIN SEEMS UNLIKELY.
SOUTHERN STREAM SYSTEM EMERGING FROM THE SOUTHWEST WED WILL MOVE
EAST ALONG THE STALLED BOUNDARY...PASSING JUST OFF THE SOUTHEAST
COAST THU INTO FRI. CONFIDENCE IN THE EXISTENCE OF THIS SYSTEM IS
ABOVE AVERAGE BUT ITS PROXIMITY TO THE REGION AS IT PASSES IS A BIG
QUESTION. THE GFS IS FAVORING A MORE SOUTHERLY/OFFSHORE TRACK WHILE
THE ECMWF IS A LITTLE FARTHER NORTH AND CLOSER TO THE SOUTHEAST
COAST. THIS IS DOWN TO THE HANDLING OF THE SOUTHERN STREAM
SHORTWAVE...SOMETHING WHICH WILL BE FLESHED OUT EARLY NEXT WEEK AS
THE INCOMING SHORTWAVE RESPONSIBLE FOR KICKING THE SOUTHERN STREAM
SYSTEM OUT OF THE SOUTHWEST MOVES INTO THE UPPER AIR NETWORK. FOR
NOW WILL CONTINUE WITH INHERITED SILENT POP. ALTHOUGH HARD TO SAY AT
THIS POINT IT WOULD APPEAR P TYPE ISSUES MAY NOT BE A PROBLEM LATE
IN THE PERIOD. IF THE ECMWF IS CORRECT AND THE SYSTEM IS CLOSER TO
THE COAST THEN TEMPS WOULD LIKELY BE TOO WARM. ALTERNATIVELY IF THE
GFS IS CORRECT AIR MASS MAY BE COLD ENOUGH FOR FROZEN PRECIP BUT THE
PRECIP WOULD REMAIN OFFSHORE.
&&
.AVIATION /18Z SATURDAY THROUGH THURSDAY/...
AS OF 18Z...SE WINDS ARE EXPECTED THIS AFTERNOON. AS COASTAL
TROUGH PUSHES INLAND. ONLY MODERATE CONFIDENCE IN THE TIMING AND
COVERAGE OF PRECIPITATION THIS AFTERNOON...INTO THE EVENING AND
OVERNIGHT HOURS. THE HRRR AND THE NAM ARE IN REASONABLE AGREEMENT
WITH A CONVERGENCE BOUNDARY OVER THE MYRTLES...REACHING ILM BY
20-22Z. MVFR CONDITIONS ARE EXPECTED IN THIS REGION...WITH
POSSIBLE IFR CONDITIONS INLAND AS WARM SOUTHWEST FLOW RIDES OVER
RELATIVELY COOLER SURFACE TEMPS.
SUNDAY...LIGHT PRECIP WILL MOVE INTO THE WESTERN TERMINALS AS A COLD
FRONT APPROACHES FROM THE WEST. THERE IS SOME DISAGREEMENT AMONG
THE MODELS WITH RESPECT TO CEILINGS. WILL STAY RATHER PESSIMISTIC
AT THIS TIME...KEEPING IFR INLAND.
EXTENDED OUTLOOK...A SERIES OF WEAK SYSTEMS WILL MOVE THROUGH THE
REGION THROUGH THE FORECAST PERIOD...WITH PERIODS OF LIGHT PRECIP
POSSIBLE EACH DAY.
&&
.MARINE...
NEAR TERM /THROUGH TONIGHT/...
AS OF 1200 PM FRIDAY...COASTAL TROUGH RUNNING UP FROM SOUTH
CAROLINA WATERS INTO THE CAPE FEAR COAST WILL PRODUCE SE WINDS
THROUGH TODAY. A PINCHED GRADIENT FROM COASTAL TROUGH WILL
CONTINUE TO TIGHTEN BETWEEN HIGH PRESSURE OFF SHORE AND FRONTAL
SYSTEM OVER THE CAROLINAS TO PRODUCE INCREASING WINDS THROUGH
TONIGHT. WINDS WILL VEER FROM SE TO S ONCE THIS COASTAL
TROUGH/WARM FRONT BLOWS NORTH OF THE AREA WATERS THROUGH TONIGHT.
THE WARM AIR RUSHING OVER THE COOLER SHELF WATERS WILL KEEP MARINE
LAYER MORE STABLE WITH STRONGER WINDS NOT MAKING IT DOWN TO WATER
SFC BUT AS YOU GO FARTHER OFF SHORE...SOUTHERLY WINDS WILL BE
STRONGER AND GUSTIER PRODUCING CHOPPY AND HIGHER SEAS. OUTER
WATERS SHOULD REACH UP 4 TO 5 FT LATER TODAY AND TONIGHT LEAVING
SCA CONDITIONS BEYOND THE 20 NM RANGE. KEPT FORECAST SEAS ON TRACK
AND SLIGHTLY LOWER THAN WAVEWATCH3 AND SWAN MODELS DUE TO THE
DIFFICULTY OF THE STRONGER WAA WINDS ALOFT MIXING DOWN TO THE
OCEAN SFC WHERE SSTS ARE IN THE 40S. WILL NEED TO EXAMINE
POTENTIAL FOR ANY SEA FOG AS TEMPS AND DEWPOINTS WARM THROUGH THE
NIGHT.
SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/...
AS OF 3 AM SATURDAY...SOUTHWEST FLOW AHEAD OF ADVANCING COLD FRONT
SUN WILL BE 10 TO 15 KT FOR MUCH OF THE DAY BEFORE DROPPING UNDER 10
KT AS THE FRONT ARRIVES LATE. NORTHERLY DEVELOPS BEHIND THE FRONT
WITH GRADIENT BECOMING PINCHED AFTER MIDNIGHT. COMBINATION OF TIGHT
GRADIENT AND COLD SURGE BEHIND THE FRONT WILL PUSH WIND SPEEDS INTO
THE 20 TO 25 KT RANGE MON AND MON NIGHT. SEAS RUNNING 3 TO 5 FT AT
THE START OF THE PERIOD BUILD TO 4 TO 7 FT MON INTO MON NIGHT.
LONG TERM /TUESDAY THROUGH WEDNESDAY/...
AS OF 3 AM SATURDAY...PINCHED GRADIENT TUE MORNING WILL WEAKEN
DURING THE DAY AS SURFACE HIGH SLIDES EAST...DROPPING NORTHEAST FLOW
FROM 15 TO 20 KT TUE MORNING TO UNDER 10 KT BY AFTERNOON. SURFACE
RIDGE AXIS SHIFTS OFFSHORE TUE NIGHT WITH A BRIEF PERIOD OF WEST-
SOUTHWEST FLOW SETTING UP WED AHEAD OF THE NEXT COLD FRONT. INITIALLY
FRONT LACKS COLD ADVECTION OR A GRADIENT BUT NORTHERLY FLOW WILL
START INCREASING LATE IN THE PERIOD. GRADIENT WILL BECOME MORE
DEFINED IN RESPONSE TO SYSTEM EMERGING FROM THE GULF OF
MEXICO...INCREASING NORTHEAST FLOW. SEAS 3 TO 5 FT TUE DROP TO 2 TO
4 FT TUE NIGHT AND WED THEN BUILD TO 3 TO 5 FT LATE IN THE PERIOD.
&&
.ILM WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
NC...NONE.
MARINE...NONE.
&&
$$
NEAR TERM...RGZ
SHORT TERM...III
LONG TERM...III
AVIATION...DL/RGZ
AREA FORECAST DISCUSSION
NWS RALEIGH NC
1015 AM EST SAT FEB 21 2015
.SYNOPSIS...FRIGID HIGH PRESSURE WILL RETREAT OFF THE MID-ATLANTIC
COAST TODAY. A COLD FRONT WILL APPROACH FROM THE WEST TONIGHT... AND
WILL MOVE THROUGH THE AREA ON SUNDAY.
&&
.NEAR TERM /SATURDAY THROUGH SUNDAY NIGHT/...
AS OF 1015 AM SATURDAY...
SHORTWAVE TROUGH OVER THE CENTRAL PLAIN/MID MS VALLEY THIS MORNING
WILL MOVE NEWD INTO THE OHIO VALLEY THIS AFTERNOON AND THEN INTO THE
NEW ENGLAND TONIGHT. ASSOCIATED SFC WAVE AND FRONTAL ZONE WILL
ADVANCE EAST INTO THE TN AND OHIO VALLEY TODAY...REACHING THE
CENTRAL AND SOUTHERN APPALACHIANS AOA 12Z SUNDAY.
MORNING UPDATE... RADAR ECHOES HAVE BEEN FILLING IN OVER THE FAR
NORTHWEST PIEDMONT SINCE 12Z...THOUGH THE REFLECTIVITY VALUES ARE
VERY WEAK AND KINT HAS ONLY REPORTED 9SM VISBILITY THROUGHOUT THE
LIGHT SNOW....SUGGESTING THE SNOW IS VERY LIGHT. RAP MOISTURE
FIELDS SHOW A COUPLE MORE HOURS OF (NEAR) SATURATION ABOVE -10C AND
A SLIGHTLY HEAVIER AREA OF SNOW LOOKS POISED TO POSSIBLY CLIP THE
NORTHWESTERN HALF OF FORSYTH COUNTY. SO FAR THERE HAVE BEEN NO
REPORTS OF ACCUMULATION...THOUGH A DUSTING CERTAINLY SEEMS POSSIBLE.
HAVE ISSUED AN SPS TO HIGHLIGHT ANY LIGHT ACCUMULATION AND ISOLATED
TRAVEL CONCERN...BUT WITHOUT GREATER RATES THIS DOESN`T WARRANT AN
ADVISORY. DRYING IN THE MID-LEVELS CAUSE THE LIGHT SNOW TO
END...POSSIBLY AS SLEET ON THE TAIL END...AND THEN NEARLY ALL
GUIDANCE HAS THE WESTERN PIEDMONT DRY AFTER 18Z.
TO THE EAST...MOISTURE ADVECTION FROM OFF THE SC COAST IS RAMPING
UP...EVIDENT IN THE QUICK SURGE OF 2000-3000FT CEILINGS ACROSS THE
SOUTHERN COASTAL PLAIN. AT THE SURFACE...THE RIDGE OF HIGH PRESSURE
EXTENDING FROM THE OFF THE DELMARVA IS STILL HOLDING ON AND SURFACE
WINDS HAVE YET TO REALLY TURN TO SOUTHEASTERLY. WITH TEMPS
CURRENTLY IN THE UPPER 20S/ LOWER 30S AND DEWPOINTS STILL IN THE
TEENS...THE WETBULB FREEZING LINE IS STILL SUPPRESSED TO THE COAST.
HOWEVER... AS THE HIGH WEAKENS...WINDS ARE STILL FORECAST TO SHIFT
AND DEWPOINTS SHOULD THEN RISE MORE DRAMATICALLY....CAUSING THE
WETBULB FREEZING LINE TO QUICKLY RETREAT THROUGH THE PIEDMONT. HI-
RES MODELS AND MAINLY NAM/GFS INDICATED SOME SHOWERY TYPE PRECIP
BREAKING OUT ACROSS THE COASTAL PLAIN...BUT BY THEN WARMING WILL
KEEP EVERYTHING LIQUID. NO MAJOR CHANGES TO THE FORECAST FOR THE
EASTERN AREAS. HIGHS RANGING FROM THE MID 30S NORTHWEST TO AROUND
50 SOUTHEAST. -BLS
TONIGHT THROUGH SUNDAY NIGHT: RAIN CHANCES WILL INCREASE AFTER
MIDNIGHT AND INTO THE DAY ON SUNDAY OWING TO STRENGTHENING MOISTURE
CONVERGENCE WITH THE APPROACH OF THE FRONT INTO THE AREA. PWATS
INCREASE TO 1.0-1.25" WITH THE FRONT MOVING THROUGH THE AREA BETWEEN
12Z SUNDAY TO 00Z MONDAY. SOUNDINGS/THERMAL PROFILES SUPPORT ALL
LIQUID WITH A SOLID BAND OF RAIN ACCOMPANYING THE FRONT INTO THE
PIEDMONT BY THE MID TO LATE MORNING HOURS...THEN WEAKENING/FALLING
APART AS IT REACHES THE COASTAL PLAIN AS DEEPER MOISTURE EXITS
OFFSHORE WITH THE ATTENDANT LOW-LEVEL JET. RAIN CHANCES COULD LINGER
IN THE WAKE OF THE FRONT SUNDAY NIGHT AND INTO MONDAY ACROSS THE FAR
SOUTHERN ZONES AS THE H8 TROUGH IS SLOW TO CLEAR THE AREA. QPF
AMOUNTS RANGING FROM A TENTH IN THE EAST TO A HALF INCH ACROSS THE
WEST.
LOWS SUNDAY NIGHT IN THE LOWER TO MID 30S NW TO MID/UPPER SE. HIGHS
SUNDAY WILL DEPEND ON TIMING/COVERAGE OF PRECIP...RANGING FROM LOWER
50 NW TO UPPER 50S/NEAR 60 SE. CAA WILL GOVERN LOWS SUNDAY NIGHT...
RANGING FROM NEAR 30 NORTH TO UPPER 30S SOUTH.
&&
.SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/...
AS OF 250 AM SATURDAY...
SURFACE COLD FRONT WILL BE OFFSHORE MONDAY MORNING...WITH COLD HIGH
PRESSURE BUILDING EAST ACROSS THE OHIO VALLEY AND SPILLING DOWN THE
EAST COAST. THERE WILL BE A SMALL POTENTIAL FOR SOME LINGERING
ANAFRONTAL LIGHT RAIN IN THE EAST MONDAY MORNING AS THE TRAILING H85
TROF MOVES ACROSS THE AREA. OTHERWISE...WILL LIKELY SEE SOME
AFTERNOON SUN...ESPECIALLY ACROSS THE NORTHWEST...TO FEEBLY OFFSET
STRENGTHENING COLD AIR ADVECTION. HIGHS WILL STRUGGLE TO REACH 40
ACROSS THE NORTH...WITH LOWER 40S ACROSS THE SOUTHERN TIER...A GOOD
15 DEGREES BELOW NORMAL. AXIS OF THE SURFACE HIGH WILL BE ALIGNED
DOWN THE COAST MONDAY NIGHT...WITH MINS POTENTIALLY IN THE UPPER
TEENS ACROSS THE NORTHERN TIER TO LOW 20S SOUTH. HIGHS TUESDAY WILL
BE SIMILAR...PERHAPS EVEN A DEGREE OR TWO COOLER...THAN MONDAY UNDER
THE HIGH PRESSURE...MOSTLY IN THE UPPER 30S. SURFACE HIGH SHIFTING
OFFSHORE AND INCREASED MID CLOUDINESS AHEAD OF AN APPROACHING FRONT
TUESDAY NIGHT WILL SOFTEN THE DIURNAL CRASH A BIT...WITH MINS IN THE
LOW TO MID 20S.
&&
.LONG TERM /WEDNESDAY THROUGH FRIDAY/...
AS OF 250 AM SATURDAY...
...WELL BELOW NORMAL TEMPERATURES WILL CONTINUE INTO THE
WEEKEND...
UPPER PATTERN WILL TRANSITION TO FLATTER...NEAR ZONAL FLOW ALOFT AS
BROAD TROFFING SETS UP ACROSS THE NORTHERN CONUS THROUGH THE
REMAINDER OF THE WEEK. THIS WILL EFFECTIVELY SUPPRESS MOISTURE
TRANSPORT SOUTH ACROSS THE GULF STATES. IN THE ABSENCE OF
COMPLEMENTARY SYNOPTIC SIGNALS IN THE LATEST MODEL RUNS...THIS
PATTERN SUGGESTS MINIMAL PRECIP CHANCES THROUGH THE WEEK...AND WILL
MAINTAIN ONGOING DRY FORECAST. WE WILL HAVE A REINFORCING COLD FRONT
MOVE ACROSS ON WEDNESDAY...WITH BRIEF WARM AIR ADVECTION AHEAD OF
THE FRONT BUMPING HIGHS UP A BIT INTO THE MID 40S. BEHIND THE
FRONT...A SOUTHERN STREAM SHORT WAVE INDUCES CYCLOGENESIS ALONG THE
FRONTAL BOUNDARY ACROSS NORTHERN FLORIDA WEDNESDAY NIGHT...AND THE
LATEST ECMWF KEEPS THE LOW CLOSE ENOUGH TO THE COAST TO WRAP SOME
PRECIP BACK INTO EASTERN NC...BUT WILL NEED TO SEE LATER MODEL
CONSENSUS ON THIS SOLUTION BEFORE INTRODUCING POPS AT THIS POINT.
THE UPSHOT...COLDER AIR RETURNS FOR LATE WEEK...WITH HIGHS BOTH
THURSDAY AND FRIDAY IN THE UPPER 30S NORTH TO BARELY 40 ACROSS THE
SOUTHERN TIER AFTER MORNING LOWS MOSTLY FROM 20 TO 25.
&&
.AVIATION /12Z SATURDAY THROUGH WEDNESDAY/...
AS OF 645 AM SATURDAY...
24 HOUR TAF PERIOD: MOISTURE WILL BE ON THE INCREASE AS HIGH
PRESSURE MOVES FURTHER OFFSHORE AND SOUTHERLY FLOW DEEPENS AHEAD OF
A COLD FRONT WHICH WILL MOVE ACROSS THE AREA AROUND MID DAY ON
SUNDAY. HAVE SEEN SOME PATCHY -SN APPROACHING GSO/INT WITH CEILINGS
FALLING OVERNIGHT TO AROUND 4K FEET IN THE WEST AND SOUTH. EXPECT
MVFR CEILINGS AT GSO/INT AROUND 15Z WITH PATCHY PREFRONTAL LIGHT
RAIN AND/OR SNOW INTO EARLY AFTERNOON. RAIN IS EXPECTED TO SURGE
NORTH INTO CENTRAL NC THIS MORNING...WITH CEILINGS FALLING TO MVFR
AROUND 18Z WITH PATCHY R- AT THE EASTERN TAF SITES FROM 18-22Z.
WARM AND MOIST SOUTHERLY FLOW WILL CONTINUE WITH TEMPERATURES RISING
OVERNIGHT. MVFR CEILINGS AND POSSIBLY VISIBILITIES ARE EXPECTED AT
ALL SITES OVERNIGHT WITH HEAVIER RAIN SPREADING EAST ACROSS THE
AREA...INTO THE WEST AROUND 06Z...AND INTO THE EAST BY 09Z. CEILINGS
WILL FALL TO IFR WITH THE RAIN SHIELD...WITH CONDITIONS CONTINUING
INTO SUNDAY AFTERNOON.
OUTLOOK: APPROACHING COLD FRONT AND ASSOCIATED RAIN AND SUB-VFR
CONDITIONS WILL CONTINUE TO IMPACT THE AREA SUNDAY AFTERNOON...
PERHAPS LINGERING WELL INTO THE OVERNIGHT AS DRYING WILL BE SLOW TO
ENSUE...EVEN AS WINDS SHIFT AROUND TO NORTHERLY SUNDAY EVENING 00Z.
VFR CONDITIONS WILL BE PREVALENT TUE AND WED.
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...CBL
NEAR TERM...CBL/BLS
SHORT TERM...MLM
LONG TERM...MLM
AVIATION...MLM
AREA FORECAST DISCUSSION
NWS CHARLESTON WV
1253 PM EST SAT FEB 21 2015
.SYNOPSIS...
LOW PRESSURE SYSTEM BRINGS WINTRY MIX TONIGHT THROUGH SATURDAY
NIGHT. COLD AGAIN FOR THE END OF THE WEEKEND AND EARLY NEXT WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
FORECAST ON TRACK WITH NO CHANGES PLANNED. WE ARE SEEING A
SMORGASBORD WINTRY PRECIPITATION ACROSS THE CWA. IN A NUTSHELL...
WHEREVER WE ARE SEEING STRONG DYNAMIC LIFT ACROSS THE SOUTHERN
HALF OF THE CWA THERE IS SNOW IS FALLING...EVEN AS TEMPS ARE ABOVE
FREEZING. DYNAMIC COOLING ALOFT HELPING TO OFFSET WARM AIR
INTRUSION IN THESE AREAS. OTHERWISE...FREEZING RAIN RULES THE
ROOST IN THE SOUTH. ACROSS THE NORTHERN HALF OF THE CWA...WE ARE
SEEING MAINLY SNOW WHERE THE COLD AIR DOME IS MORE FIRMLY
ENTRENCHED. HRRR SEEMS TO HAVE A DECENT HANDLE ON AMOUNT OF
WARMING TO OCCUR FROM WARM AIR INTRUSION ALOFT AND WE ARE GOING TO
STICK TO ITS TRENDS IN THE NEAR TERM. STARTING AT ABOUT 19Z WE
SHOULD SEE TRANSITION FROM SOUTH TO NORTH THAT CHANGES US TO AN
ALL RAIN IN THE WX GRIDS...THE EXCEPTION BEING SE OH AND THE
EASTERN MOUNTAINS OF NE WV WHERE SUB FREEZING TEMPS REMAIN AT ALL
LEVELS.
&&
.SHORT TERM /SUNDAY THROUGH TUESDAY/...
A BRIEF PERIOD OF UPSLOPE ENDS THE LOW PRESSURE SYSTEM EVENT FOR THE
CENTRAL APPALACHIANS SUNDAY WITH THE LAST OF THE FLAKES FALLING
EARLY SUNDAY NIGHT. A RETURN TO THE ARCTIC AIR...NOT AS JARRING AS
THE LAST ONE...FOLLOWS FOR THE BEGINNING OF THE WORK WEEK. HIGH
PRESSURE BRINGS A DRY PERIOD THROUGH THE REMAINDER OF THE SHORT
TERM...WITH MODELS CLEARING THE SKY MONDAY NIGHT. CENTER OF HIGH
PRESSURE WILL BE JUST TO THE SOUTHWEST...SO DECOUPLING LIKELY WITH
ANOTHER GOOD RADIATIONAL COOLING NIGHT. TAKING THE CONSERVATIVE
APPROACH FOR NOW...BUT IF THE MODEL SOLUTIONS HOLD AND SNOW REMAINS
ON THE GROUND DESPITE THE WET FORECAST TODAY IN PLACES...MAY NEED TO
LOWER THESE TEMPERATURES.
&&
.LONG TERM /TUESDAY NIGHT THROUGH FRIDAY/...
OVERALL NOTHING TOO SIGNIFICANT IN THE LONG TERM...ALTHOUGH IT WILL
CONTINUE TO BE COLD WITH PERIODS OF LIGHT SNOW SHOWERS AT TIMES.
NORTHWESTERLY FLOW TO START THE PERIOD...WITH THE POSSIBILITY OF
SOME LIGHT SNOW SHOWERS LINGERING MONDAY NIGHT INTO EARLY TUESDAY.
THESE WILL TAPER OFF HOWEVER AS HIGH PRESSURE BUILDS IN FROM THE
WEST. MID WEEK BECOMES A LITTLE MORE UNCERTAIN. CHANCES LOOK GOOD
FOR A CLIPPER TYPE SYSTEM TO AFFECT THE AREA MID WEEK...BRINGING
SOME LIGHT SNOW SHOWERS...BUT SOME UNCERTAINTY AS TO WHETHER
MOISTURE FROM A SYSTEM TO THE SOUTH WILL BE ABLE TO WORK ITS WAY
INTO THE AREA. FOR NOW...MAINTAINED SLIGHT CHANCE TO CHANCE POPS MID
WEEK TO ACCOUNT FOR THESE VARIABLES...AND BROAD BRUSHED THE PERIOD.
TEMPS LOOK TO REMAIN BELOW NORMAL FOR THE PERIOD.
&&
.AVIATION /18Z SATURDAY THROUGH THURSDAY/...
GENERALLY IFR/LIFR AREA WIDE THROUGH THE PERIOD. SLOW TO IMPROVE
CONDITIONS LATE TONIGHT CAUSE THINK THAT FOG WILL SETTLE IN ACROSS
LEFTOVER SNOWPACK AS WARM AND MOIST AIR ROLLS ON IN THIS EVENING.
LATE IN THE PERIOD...WE BRING IN A HINT OF IMPROVEMENT AS COLD FRONT
CROSS FROM WEST TO EAST TO HELP SCOUR OUT FOG.
FOR THE REMAINDER OF TODAY...SITES CONTINUE TO SEE A TRANSITION FROM
FREEZING PRECIPITATION TO MOSTLY RAIN...REACHING KEKN BY AROUND
01Z THIS EVENING.
GUSTY SOUTHERLY WINDS TO 30 MPH ON MOUNTAIN RIDGE TOPS INVOF OF
85H LLJ TRANSITIONING ACROSS CWA.
FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 18Z SUNDAY...
FORECAST CONFIDENCE: LOW...ESPECIALLY WITH TIMING OF AND TRANSITION
TO MIXED PRECIP AND ANY FOG DEVELOPMENT.
ALTERNATE SCENARIOS: LARGE VARIABILITY IN PRECIP TYPE AND
TIMING...ESPECIALLY CENTRAL AND NORTH.
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 18 19 20 21 22 23 00 01 02 03 04 05
EST 1HRLY 13 14 15 16 17 18 19 20 21 22 23 00
CRW CONSISTENCY L H H H H H H H H H L L
HTS CONSISTENCY M M M L M M H L L L L L
BKW CONSISTENCY L M M M M M H M M L M L
EKN CONSISTENCY M M M L H H H H H M H M
PKB CONSISTENCY L M M H H H H H M M M L
CKB CONSISTENCY L M M H H H M H H H H M
AFTER 18Z SUNDAY...
IFR IN WINTRY PRECIP ACROSS MOUNTAIN SITES SUNDAY NIGHT.
&&
.RLX WATCHES/WARNINGS/ADVISORIES...
WV...WINTER STORM WARNING UNTIL 7 PM EST THIS EVENING FOR
WVZ007>011-014>020-027>032-035>040.
WINTER STORM WARNING UNTIL 5 PM EST THIS AFTERNOON FOR WVZ005-
006-013-024>026-033-034.
WINTER STORM WARNING UNTIL 4 AM EST SUNDAY FOR WVZ046-047.
OH...WINTER STORM WARNING UNTIL 7 PM EST THIS EVENING FOR OHZ066-
067-075-076-083>086.
WINTER STORM WARNING UNTIL 5 PM EST THIS AFTERNOON FOR OHZ087.
KY...WINTER STORM WARNING UNTIL 5 PM EST THIS AFTERNOON FOR
KYZ101>103-105.
VA...WINTER STORM WARNING UNTIL 5 PM EST THIS AFTERNOON FOR VAZ003-
004.
&&
$$
SYNOPSIS...JMV/26
NEAR TERM...KMC
SHORT TERM...26
LONG TERM...SL
AVIATION...KMC
AREA FORECAST DISCUSSION
NWS CHARLESTON WV
937 AM EST SAT FEB 21 2015
.SYNOPSIS...
LOW PRESSURE SYSTEM BRINGS WINTRY MIX TONIGHT THROUGH SATURDAY
NIGHT. COLD AGAIN FOR THE END OF THE WEEKEND AND EARLY NEXT WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
FORECAST ON TRACK WITH NO CHANGES PLANNED. WE ARE SEEING A
SMORGASBORD WINTRY PRECIPITATION ACROSS THE CWA. IN A NUTSHELL...
WHEREVER WE ARE SEEING STRONG DYNAMIC LIFT ACROSS THE SOUTHERN
HALF OF THE CWA THERE IS SNOW IS FALLING...EVEN AS TEMPS ARE ABOVE
FREEZING. DYNAMIC COOLING ALOFT HELPING TO OFFSET WARM AIR
INTRUSION IN THESE AREAS. OTHERWISE...FREEZING RAIN RULES THE
ROOST IN THE SOUTH. ACROSS THE NORTHERN HALF OF THE CWA...WE ARE
SEEING MAINLY SNOW WHERE THE COLD AIR DOME IS MORE FIRMLY
ENTRENCHED. HRRR SEEMS TO HAVE A DECENT HANDLE ON AMOUNT OF
WARMING TO OCCUR FROM WARM AIR INTRUSION ALOFT AND WE ARE GOING TO
STICK TO ITS TRENDS IN THE NEAR TERM. STARTING AT ABOUT 19Z WE
SHOULD SEE TRANSITION FROM SOUTH TO NORTH THAT CHANGES US TO AN
ALL RAIN IN THE WX GRIDS...THE EXCEPTION BEING SE OH AND THE
EASTERN MOUNTAINS OF NE WV WHERE SUB FREEZING TEMPS REMAIN AT ALL
LEVELS.
&&
.SHORT TERM /SUNDAY THROUGH TUESDAY/...
A BRIEF PERIOD OF UPSLOPE ENDS THE LOW PRESSURE SYSTEM EVENT FOR THE
CENTRAL APPALACHIANS SUNDAY WITH THE LAST OF THE FLAKES FALLING
EARLY SUNDAY NIGHT. A RETURN TO THE ARCTIC AIR...NOT AS JARRING AS
THE LAST ONE...FOLLOWS FOR THE BEGINNING OF THE WORK WEEK. HIGH
PRESSURE BRINGS A DRY PERIOD THROUGH THE REMAINDER OF THE SHORT
TERM...WITH MODELS CLEARING THE SKY MONDAY NIGHT. CENTER OF HIGH
PRESSURE WILL BE JUST TO THE SOUTHWEST...SO DECOUPLING LIKELY WITH
ANOTHER GOOD RADIATIONAL COOLING NIGHT. TAKING THE CONSERVATIVE
APPROACH FOR NOW...BUT IF THE MODEL SOLUTIONS HOLD AND SNOW REMAINS
ON THE GROUND DESPITE THE WET FORECAST TODAY IN PLACES...MAY NEED TO
LOWER THESE TEMPERATURES.
&&
.LONG TERM /TUESDAY NIGHT THROUGH FRIDAY/...
OVERALL NOTHING TOO SIGNIFICANT IN THE LONG TERM...ALTHOUGH IT WILL
CONTINUE TO BE COLD WITH PERIODS OF LIGHT SNOW SHOWERS AT TIMES.
NORTHWESTERLY FLOW TO START THE PERIOD...WITH THE POSSIBILITY OF
SOME LIGHT SNOW SHOWERS LINGERING MONDAY NIGHT INTO EARLY TUESDAY.
THESE WILL TAPER OFF HOWEVER AS HIGH PRESSURE BUILDS IN FROM THE
WEST. MID WEEK BECOMES A LITTLE MORE UNCERTAIN. CHANCES LOOK GOOD
FOR A CLIPPER TYPE SYSTEM TO AFFECT THE AREA MID WEEK...BRINGING
SOME LIGHT SNOW SHOWERS...BUT SOME UNCERTAINTY AS TO WHETHER
MOISTURE FROM A SYSTEM TO THE SOUTH WILL BE ABLE TO WORK ITS WAY
INTO THE AREA. FOR NOW...MAINTAINED SLIGHT CHANCE TO CHANCE POPS MID
WEEK TO ACCOUNT FOR THESE VARIABLES...AND BROAD BRUSHED THE PERIOD.
TEMPS LOOK TO REMAIN BELOW NORMAL FOR THE PERIOD.
&&
.AVIATION /14Z SATURDAY THROUGH WEDNESDAY/...
12Z SATURDAY THRU 12Z SUNDAY...
GENERALLY IFR/LIFR AREA WIDE THRU 00Z...THEN SLOWLY IMPROVING FROM
WEST TO EAST TO MVFR THROUGH 07Z WITH A COLD FRONT THAT MOVES EAST
ACROSS THE AREA.
THRU 15Z...SNOW ACROSS THE NORTH...A WINTRY MIX OF SLEET AND
FREEZING RAIN CENTRAL...FREEZING RAIN SOUTH. AFTER 15Z SNOW
CONTINUES NORTH...WINTRY MIX TRANSITIONS TO RAIN ACROSS THE SOUTH BY
15Z...AND ACROSS THE CENTRAL BY 17Z. THESE CONDITIONS PERSIST TIL A
COLD FRONT PASSES THRU TONIGHT. GUSTY SOUTHERLY WINDS TO 30 MPH ON
MOUNTAIN RIDGE TOPS.
AFTER 00Z...A WINTRY MIX RETURNING TO MOST AREAS BEFORE ENDING IN
THE WEST BY 06Z...BUT IFR/LIFR STILL HOLDS FOR THE MOST PART. WINDS
DIMINISHING.
FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 12Z SUNDAY...
FORECAST CONFIDENCE: LOW...ESPECIALLY WITH TIMING OF AND TRANSITION
TO MIXED PRECIP.
ALTERNATE SCENARIOS: LARGE VARIABILITY IN PRECIP TYPE AND
TIMING...ESPECIALLY CENTRAL AND NORTH.I
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 14 15 16 17 18 19 20 21 22 23 00 01
EST 1HRLY 09 10 11 12 13 14 15 16 17 18 19 20
CRW CONSISTENCY M M M M M M H H H M M M
HTS CONSISTENCY H H H H H M M M H H H M
BKW CONSISTENCY M M M M M M H H H L M H
EKN CONSISTENCY L H H M M M M M M M M M
PKB CONSISTENCY H M M M M M H M M M M M
CKB CONSISTENCY L H H H H M H M M M M M
AFTER 12Z SUNDAY...
IFR IN MIXED WINTRY PRECIPITATION AND RAIN SATURDAY NIGHT.
&&
.RLX WATCHES/WARNINGS/ADVISORIES...
WV...WINTER STORM WARNING UNTIL 7 PM EST THIS EVENING FOR
WVZ007>011-014>020-027>032-035>040.
WINTER STORM WARNING UNTIL 5 PM EST THIS AFTERNOON FOR WVZ005-
006-013-024>026-033-034.
WINTER STORM WARNING UNTIL 4 AM EST SUNDAY FOR WVZ046-047.
OH...WINTER STORM WARNING UNTIL 7 PM EST THIS EVENING FOR OHZ066-
067-075-076-083>086.
WINTER STORM WARNING UNTIL 5 PM EST THIS AFTERNOON FOR OHZ087.
KY...WINTER STORM WARNING UNTIL 5 PM EST THIS AFTERNOON FOR
KYZ101>103-105.
VA...WINTER STORM WARNING UNTIL 5 PM EST THIS AFTERNOON FOR VAZ003-
004.
&&
$$
SYNOPSIS...JMV/26
NEAR TERM...KMC
SHORT TERM...26
LONG TERM...SL
AVIATION...JMV
AREA FORECAST DISCUSSION
NWS CLEVELAND OH
647 AM EST SAT FEB 21 2015
.SYNOPSIS...
A FAST MOVING LOW PRESSURE SYSTEM WILL MOVE NORTHEAST ACROSS CENTRAL
OHIO INTO WESTERN PENNSYLVANIA TODAY. AN ARCTIC COLD FRONT WILL
SLIDE SOUTHEAST ACROSS THE AREA MID DAY ON SUNDAY. HIGH PRESSURE
WILL BUILD EAST EXTENDING A RIDGE EAST ACROSS THE LOCAL AREA SUNDAY
NIGHT INTO MONDAY. ANOTHER COLD FRONT WILL MOVE SOUTH ACROSS THE
AREA ON WEDNESDAY.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
SNOW IS QUICKLY SPREADING NORTHEAST INTO THE AREA AT THIS TIME.
MAIN AXIS OF THE HEAVIER SNOW APPEARS TO BE ON A LINE ACROSS THE
SOUTHERN PORTIONS OF THE FORECAST AREA WHERE THE WINTER STORM
WARNING IS IN EFFECT. ONLY MADE SOME MINOR ADJUSTMENTS TO HOURLY
TEMPERATURES AT THIS TIME. REST OF THE FORECAST UNCHANGED.
PREVIOUS DISCUSSION...
LOW PRESSURE WILL MOVE NORTHEAST ACROSS THE FORECAST AREA SPREADING
SNOW INTO THE REGION. LATEST RADAR SHOWS SNOW EXPANDING AND MOVING
NORTHEAST AT THIS TIME AND SHOULD COVER MUCH OF THE AREA BY SHORTLY
AFTER SUNRISE. AT THIS TIME IT LOOKS THE THE PRECIPITATION SHOULD BE
ALL SNOW. THERE IS THE POSSIBILITY THAT SOME FREEZING RAIN OR SLEET
COULD MIX IN ACROSS THE DEEP SOUTH. BUT SINCE IT IS A LOW CONFIDENCE
WILL LEAVE IT OUT FOR NOW. WARM AIR ADVECTION IN ADVANCE OF THE LOW
PRESSURE SYSTEM WILL BOOST TEMPERATURES TO AROUND 30 IN THE SOUTH
AND MOSTLY UPPER 20S IN THE NORTH TODAY. SNOW ACCUMULATIONS DROPPED
BACK SLIGHTLY FROM PREVIOUS FORECAST AS BULK OF THE HEAVIER
PRECIPITATION APPEARS IT WILL REMAIN A BIT FURTHER SOUTH THAN
THOUGHT. LATEST MODEL RUNS HAVE THE STRONGEST UPWARD VERTICAL MOTION
ACROSS THE OHIO VALLEY REGION. I HAVE A GUT FEELING WE MAY BE
PULLING BACK ON THE SNOW AMOUNTS AS THE DAY PROGRESSES. EVEN THE
LATEST HRRR MODEL IS SUGGESTING A TREND TOWARD FURTHER SOUTH.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH TUESDAY NIGHT/...
LOW PRESSURE PULLS OUT TO THE EAST ALLOWING COLDER AIR TO RETURN IN
THE WAKE OF THE LOW. PRECIPITATION WILL QUICKLY PULL OUT TO THE EAST
ALLOWING AN ARCTIC COLD FRONT TO MOVE SOUTHEAST DURING THE DAY
SUNDAY. THIS FRONT WILL USHER IN ANOTHER ROUND OF ARCTIC AIR FOR
SUNDAY NIGHT INTO MONDAY. SOME LAKE EFFECT SNOW SHOWERS WILL DEVELOP
BEHIND THE FRONT AS WELL SUNDAY INTO SUNDAY NIGHT. EVENTUALLY THE
HIGH PRESSURE RIDGE WILL BUILD IN ON MONDAY PUSHING THE THREAT OF
THE PRECIPITATION OUT OF THE AREA. REST OF THE AREA WILL SEE SOME
POSSIBILITY OF SNOW SHOWERS WITH THE ARCTIC FRONT BUT SHOULD SEE
FAIR WEATHER GOING INTO MONDAY.
ANOTHER LOW PRESSURE SYSTEM WILL MOVE EAST ACROSS NORTHERN CANADA
AND FORCE A COLD FRONT SOUTH ACROSS THE AREA. THIS FEATURE WILL
BRING WITH IT ANOTHER ROUND OF SNOW SHOWERS TO THE REGION.
UNFORTUNATELY...DUE TO THE REINFORCING SHOTS OF COLD AIR INTO THE
AREA...THE COLD AIR WILL CONTINUE.
APOLOGIES FOR GETTING THIS OUT SO LATE.
&&
.LONG TERM /WEDNESDAY THROUGH FRIDAY/...
UPPER LEVEL TROUGH WILL BE MOVING EAST OF THE REGION EARLY ON
WEDNESDAY WITH SOME SNOW SHOWERS CONTINUING THROUGH THE DAY. AMOUNTS
SHOULD BE ON LIGHTER SIDE WITH A LARGE AMOUNT OF ICE ON THE GREAT
LAKES. HOWEVER A COUPLE INCHES OF FLUFFY SNOW WILL BE POSSIBLE. HIGH
PRESSURE WILL BE RIDGING INTO THE REGION THURSDAY INTO THURSDAY
NIGHT BUT PROBABLY WONT DECREASE THE SNOW SHOWERS MUCH UNTIL THE
OVERNIGHT HOURS OF THURSDAY NIGHT. HIGH PRESSURE LOOKS TO BE
OVERHEAD FRIDAY INTO INTO FRIDAY NIGHT WITH DRY AND COLD CONDITIONS.
TEMPERATURES THROUGH THE LONG TERM WILL REMAIN WELL BELOW AVERAGE
WITH HIGHS STRUGGLING TO GET INTO THE TEENS. CURRENT FORECAST MAY
END UP BEING A FEW DEGREES WARM IF SKIES CAN BECOME CLEAR TO PARTLY
CLOUDY SOONER THAN ANTICIPATED. LOWS WILL RANGE FROM AROUND ZERO TO
A FEW DEGREES BELOW ZERO. THURSDAY NIGHT LOOKS TO BE THE COLDEST
NIGHT WITH BEST CHANCES OF CLEAR SKIES AND LIGHT WINDS. THESE LOWS
MAY BE ADJUSTED LOWER FOR THURSDAY NIGHT.
&&
.AVIATION /12Z SATURDAY THROUGH WEDNESDAY/...
IFR CONDITIONS ACROSS MUCH OF THE AREA AS LIGHT SNOW SPREADS
ACROSS NORTHERN OHIO. THE EXCEPTIONS AS OF 1145Z ARE ACROSS NW
OHIO AND NW PA. HOWEVER EXPECT MVFR/IFR SNOW TO OCCUR AT THESE
LOCATIONS THROUGH THE DAY. HEAVIEST SWATH OF SNOW WILL BE ACROSS
THE SOUTHERN HALF OF THE REGION FROM MARION TO YOUNGSTOWN. THIS IS
THE AREA WHERE A VISIBILITY OF 1/2 MILE OR LESS WILL BE POSSIBLE
FOR SEVERAL HOURS. ELSEWHERE THERE WILL BE BURST OF HEAVIER SNOW
THROUGH THE AFTERNOON. CONDITIONS BEGIN TO IMPROVE THIS EVENING AS
THE SNOW MOVES NE WITH THE WEAKENING AREA OF LOW PRESSURE. MVFR
CONDITIONS SHOULD SPREAD ACROSS THE REGION FROM SOUTHWEST TO
NORTHEAST AFTER 02Z.
.OUTLOOK...NON VFR FAR NE OHIO AND NW PA POSSIBLY LINGERING INTO
MONDAY. EXPECT NON VFR AGAIN TUESDAY AFTERNOON THEN CONTINUING
THROUGH WEDNESDAY.
&&
.MARINE...
LOW PRESSURE WILL MOVE FROM THE LOWER OHIO RIVER VALLEY ACROSS
CENTRAL OHIO INTO WESTERN NY THIS EVENING. HOWEVER IT WILL BE
WEAKENING AS IT MOVES TO THE NORTHEAST. EXPECT TO SEE SOUTHERLY
WINDS AHEAD OF THE LOW AT 5 TO 15 KNOTS SHIFTING TO THE NORTH BY
THIS EVENING. A SURGE OF COLDER AIR WILL ARRIVE WITH THE ARCTIC COLD
FRONT ON SUNDAY WITH NORTHWEST WINDS INCREASING TO 15 TO 25 KNOTS.
WINDS WILL DECREASE BY SUNDAY NIGHT AS HIGH PRESSURE RIDGES INTO THE
REGION. THIS HIGH PRESSURE WILL QUICKLY SHIFT TO THE EAST COAST
ALLOWING LOW PRESSURE TO MOVE ACROSS SOUTHERN ONTARIO LATE TUESDAY
INTO TUESDAY NIGHT. SOUTHWESTERLY WINDS AHEAD OF THE COLD FRONT MAY
APPROACH 35 KNOTS. THIS MAY CONTINUE AS THE COLD FRONT CROSSES THE
LAKE TUESDAY NIGHT BUT WILL BE FROM A NORTHWESTERLY DIRECTION. IT
LOOKS LIKE A SMALL WINDOW OF OPPORTUNITY TO REACH GALES EITHER SIDE
OF THE FRONT AT THIS POINT AND WILL PLACE A MENTION IN THE HWO.
&&
.CLE WATCHES/WARNINGS/ADVISORIES...
OH...WINTER WEATHER ADVISORY UNTIL 10 PM EST THIS EVENING FOR
OHZ009>014-017>023-027-028-089.
WINTER STORM WARNING UNTIL 10 PM EST THIS EVENING FOR
OHZ029>033-036>038-047.
PA...WINTER WEATHER ADVISORY UNTIL 10 PM EST THIS EVENING FOR
PAZ001>003.
MARINE...NONE.
&&
$$
SYNOPSIS...LOMBARDY
NEAR TERM...LOMBARDY
SHORT TERM...LOMBARDY
LONG TERM...MULLEN
AVIATION...MULLEN
MARINE...MULLEN
AREA FORECAST DISCUSSION
NWS CLEVELAND OH
433 AM EST SAT FEB 21 2015
.SYNOPSIS...
A FAST MOVING LOW PRESSURE SYSTEM WILL MOVE NORTHEAST ACROSS CENTRAL
OHIO INTO WESTERN PENNSYLVANIA TODAY. AN ARCTIC COLD FRONT WILL
SLIDE SOUTHEAST ACROSS THE AREA MID DAY ON SUNDAY. HIGH PRESSURE
WILL BUILD EAST EXTENDING A RIDGE EAST ACROSS THE LOCAL AREA SUNDAY
NIGHT INTO MONDAY. ANOTHER COLD FRONT WILL MOVE SOUTH ACROSS THE
AREA ON WEDNESDAY.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
LOW PRESSURE WILL MOVE NORTHEAST ACROSS THE FORECAST AREA SPREADING
SNOW INTO THE REGION. LATEST RADAR SHOWS SNOW EXPANDING AND MOVING
NORTHEAST AT THIS TIME AND SHOULD COVER MUCH OF THE AREA BY SHORTLY
AFTER SUNRISE. AT THIS TIME IT LOOKS THE THE PRECIPITATION SHOULD BE
ALL SNOW. THERE IS THE POSSIBILITY THAT SOME FREEZING RAIN OR SLEET
COULD MIX IN ACROSS THE DEEP SOUTH. BUT SINCE IT IS A LOW CONFIDENCE
WILL LEAVE IT OUT FOR NOW. WARM AIR ADVECTION IN ADVANCE OF THE LOW
PRESSURE SYSTEM WILL BOOST TEMPERATURES TO AROUND 30 IN THE SOUTH
AND MOSTLY UPPER 20S IN THE NORTH TODAY. SNOW ACCUMULATIONS DROPPED
BACK SLIGHTLY FROM PREVIOUS FORECAST AS BULK OF THE HEAVIER
PRECIPITATION APPEARS IT WILL REMAIN A BIT FURTHER SOUTH THAN
THOUGHT. LATEST MODEL RUNS HAVE THE STRONGEST UPWARD VERTICAL MOTION
ACROSS THE OHIO VALLEY REGION. I HAVE A GUT FEELING WE MAY BE
PULLING BACK ON THE SNOW AMOUNTS AS THE DAY PROGRESSES. EVEN THE
LATEST HRRR MODEL IS SUGGESTING A TREND TOWARD FURTHER SOUTH.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH TUESDAY NIGHT/...
LOW PRESSURE PULLS OUT TO THE EAST ALLOWING COLDER AIR TO RETURN IN
THE WAKE OF THE LOW. PRECIPITATION WILL QUICKLY PULL OUT TO THE EAST
ALLOWING AN ARCTIC COLD FRONT TO MOVE SOUTHEAST DURING THE DAY
SUNDAY. THIS FRONT WILL USHER IN ANOTHER ROUND OF ARCTIC AIR FOR
SUNDAY NIGHT INTO MONDAY. SOME LAKE EFFECT SNOW SHOWERS WILL DEVELOP
BEHIND THE FRONT AS WELL SUNDAY INTO SUNDAY NIGHT. EVENTUALLY THE
HIGH PRESSURE RIDGE WILL BUILD IN ON MONDAY PUSHING THE THREAT OF
THE PRECIPITATION OUT OF THE AREA. REST OF THE AREA WILL SEE SOME
POSSIBILITY OF SNOW SHOWERS WITH THE ARCTIC FRONT BUT SHOULD SEE
FAIR WEATHER GOING INTO MONDAY.
ANOTHER LOW PRESSURE SYSTEM WILL MOVE EAST ACROSS NORTHERN CANADA
AND FORCE A COLD FRONT SOUTH ACROSS THE AREA. THIS FEATURE WILL
BRING WITH IT ANOTHER ROUND OF SNOW SHOWERS TO THE REGION.
UNFORTUNATELY...DUE TO THE REINFORCING SHOTS OF COLD AIR INTO THE
AREA...THE COLD AIR WILL CONTINUE.
APOLOGIES FOR GETTING THIS OUT SO LATE.
&&
.LONG TERM /WEDNESDAY THROUGH FRIDAY/...
UPPER LEVEL TROUGH WILL BE MOVING EAST OF THE REGION EARLY ON
WEDNESDAY WITH SOME SNOW SHOWERS CONTINUING THROUGH THE DAY. AMOUNTS
SHOULD BE ON LIGHTER SIDE WITH A LARGE AMOUNT OF ICE ON THE GREAT
LAKES. HOWEVER A COUPLE INCHES OF FLUFFY SNOW WILL BE POSSIBLE. HIGH
PRESSURE WILL BE RIDGING INTO THE REGION THURSDAY INTO THURSDAY
NIGHT BUT PROBABLY WONT DECREASE THE SNOW SHOWERS MUCH UNTIL THE
OVERNIGHT HOURS OF THURSDAY NIGHT. HIGH PRESSURE LOOKS TO BE
OVERHEAD FRIDAY INTO INTO FRIDAY NIGHT WITH DRY AND COLD CONDITIONS.
TEMPERATURES THROUGH THE LONG TERM WILL REMAIN WELL BELOW AVERAGE
WITH HIGHS STRUGGLING TO GET INTO THE TEENS. CURRENT FORECAST MAY
END UP BEING A FEW DEGREES WARM IF SKIES CAN BECOME CLEAR TO PARTLY
CLOUDY SOONER THAN ANTICIPATED. LOWS WILL RANGE FROM AROUND ZERO TO
A FEW DEGREES BELOW ZERO. THURSDAY NIGHT LOOKS TO BE THE COLDEST
NIGHT WITH BEST CHANCES OF CLEAR SKIES AND LIGHT WINDS. THESE LOWS
MAY BE ADJUSTED LOWER FOR THURSDAY NIGHT.
&&
.AVIATION /06Z SATURDAY THROUGH WEDNESDAY/...
HAVE SLOWED DOWN THE START OF THE SNOW SLIGHTLY BASED ON THE NEW
GUIDANCE. STILL EXPECT CONDITIONS TO DETERIORATE TO IFR SATURDAY
MORNING. PERIODS OF IFR VSBYS ARE EXPECTED MOST OF THE
DAY...ESPECIALLY IN THE SOUTH WHERE THE SNOW WILL BE THE HEAVIEST.
CONDITIONS SHOULD START TO IMPROVE FROM WEST TO EAST LATE IN THE
DAY. SOME INDICATION FROM THE NEW GUIDANCE THAT THERE COULD BE A
PERIOD OF FREEZING DRIZZLE AT THE TAIL END OF THE SNOW. SOME
UNCERTAINTY WITH THIS SCENARIO SO WILL OMIT FROM THE FORECAST FOR
NOW. SOUTHERLY WINDS HAVE GOTTEN GUSTY SOME AREAS BUT THESE SHOULD
DIE DOWN SOME OVERNIGHT. THE FLOW WILL BECOME WESTERLY SATURDAY
EVENING.
.OUTLOOK...NON VFR CONDITIONS WILL CONTINUE SATURDAY NIGHT.
CONDITIONS WILL IMPROVE TO VFR FROM THE WEST SUNDAY WITH THE
POSSIBLE EXCEPTION OF FAR NORTHEAST OHIO AND NWRN PA WHEN NON-VFR
REMAINS POSSIBLE THROUGH MONDAY. EXPECT NON VFR AGAIN TUESDAY
AFTERNOON AND TUESDAY NIGHT INTO WEDNESDAY.
&&
.MARINE...
LOW PRESSURE WILL MOVE FROM THE LOWER OHIO RIVER VALLEY ACROSS
CENTRAL OHIO INTO WESTERN NY THIS EVENING. HOWEVER IT WILL BE
WEAKENING AS IT MOVES TO THE NORTHEAST. EXPECT TO SEE SOUTHERLY
WINDS AHEAD OF THE LOW AT 5 TO 15 KNOTS SHIFTING TO THE NORTH BY
THIS EVENING. A SURGE OF COLDER AIR WILL ARRIVE WITH THE ARCTIC COLD
FRONT ON SUNDAY WITH NORTHWEST WINDS INCREASING TO 15 TO 25 KNOTS.
WINDS WILL DECREASE BY SUNDAY NIGHT AS HIGH PRESSURE RIDGES INTO THE
REGION. THIS HIGH PRESSURE WILL QUICKLY SHIFT TO THE EAST COAST
ALLOWING LOW PRESSURE TO MOVE ACROSS SOUTHERN ONTARIO LATE TUESDAY
INTO TUESDAY NIGHT. SOUTHWESTERLY WINDS AHEAD OF THE COLD FRONT MAY
APPROACH 35 KNOTS. THIS MAY CONTINUE AS THE COLD FRONT CROSSES THE
LAKE TUESDAY NIGHT BUT WILL BE FROM A NORTHWESTERLY DIRECTION. IT
LOOKS LIKE A SMALL WINDOW OF OPPORTUNITY TO REACH GALES EITHER SIDE
OF THE FRONT AT THIS POINT AND WILL PLACE A MENTION IN THE HWO.
&&
.CLE WATCHES/WARNINGS/ADVISORIES...
OH...WINTER WEATHER ADVISORY UNTIL 10 PM EST THIS EVENING FOR
OHZ009>014-017>023-027-028-089.
WINTER STORM WARNING UNTIL 10 PM EST THIS EVENING FOR
OHZ029>033-036>038-047.
PA...WINTER WEATHER ADVISORY UNTIL 10 PM EST THIS EVENING FOR
PAZ001>003.
MARINE...NONE.
&&
$$
SYNOPSIS...LOMBARDY
NEAR TERM...LOMBARDY
SHORT TERM...LOMBARDY
LONG TERM...MULLEN
AVIATION...KUBINA
MARINE...MULLEN
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
1033 AM EST SAT FEB 21 2015
.SYNOPSIS...
A WIDESPREAD SNOW EVENT WILL IMPACT CENTRAL PENNSYLVANIA TODAY
INTO EARLY TONIGHT. AN ARCTIC AIRMASS WILL THREATEN EXTREME COLD
AND DANGEROUS WIND CHILLS THROUGH EARLY NEXT WEEK. TEMPERATURES
WILL REMAIN WELL BELOW NORMAL AS COLD AIR IS REINFORCED LATER IN
THE WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
1000 AM UPDATE...ADDED YORK/LANCASTER COUNTIES TO THE WSW BASED
ON A BLEND OF PREVIOUS FCST WITH CONSENSUS OF HI RES MODEL DATA.
THIS FAVORS ALL SNOW PTYPE INTO THE EVENING WITH 1-2 INCH PER HOUR
RATES POSSIBLE OVER THE SRN TIER ZONES. THE LATEST HRRR AND 00Z
SSEO SEEM TO FAVOR MAX SNOW AMTS OVER S-CENTRAL PA FROM THE TURNPIKE
TO THE MASON DIXON LINE. THESE DATA ALSO SHOW A TRANSITION TO
WINTRY MIX /ZR AND IP/ BTWN 00-03Z OVER THE FAR SE BEFORE PCPN
ENDS AS LIGHT RAIN/DZ OR FZDZ INTO EARLY SUNDAY MORNING. RADAR
TRENDS MAY BE SHOWING THE DEVELOPMENT OF HEAVY SNOW BAND CURRENTLY
DEVELOPING OVER NRN MD (+SN AT HGR AND MRB) AND STREAKING TOWARD
THE RT30 CORRIDOR. THE HRRR HAS ALSO HINTED AT THIS FOR THE LAST
FEW RUNS.
TO THE NORTH...CUT BACK A LITTLE ON PREVIOUS SNFL AMTS IN THE
ORIGINAL WARNING/ADVY AREA SUPPORTED BY A BLEND OF 09Z SREF/06Z
GEFS ENSEMBLE MEANS AND 00Z HIGH RES MEAN/SSEO. ALSO REMOVED ICE
ACCUM FOR ALL BUT THE FAR SE WITH ANY POST-EVENT FZDZ AMTS AROUND
A TRACE. OVERALL HIGHEST CONFIDENCE IN WARNING SNOWS IS NOW OVER
THE SRN TIER ZONES AND WILL PROBABLY NEED A FEW PERIODS/BURSTS OF
MOD-HVY SNOW TO ACHIEVE IT. TERRAIN ENHANCEMENT MAY ALSO HELP.
CONFIDENCE IS MARGINAL OVER THE NRN PORTION OF THE WARNING AREA IN
AND WILL SEE HOW THINGS EVOLVE INTO THE AFTN.
THE OVERALL SYNOPTIC FORCING FOR THIS WINTER WX EVENT IS DRIVEN
PRIMARILY BY WARM ADVECTION PROCESSES WITH AN ANOMALOUS MOISTURE
FLUX SURGING NEWD INTO THE MID ATLC STATES ON NOSE OF 60+KT 850MB
JET CENTERED OVER THE TN VLY/CENTRAL APPALACHIANS. THE WARM ADVECTION
EVENT SHOULD END AS A PERIOD OF FZDZ PER MODEL SOUNDINGS SHOWING
NO ICE ALOFT AS THE PCPN TAPERS OFF.
LOW TEMPS SHOULD OCCUR EARLY TONIGHT WITH A NON-DIURNAL TREND
FCST OVERNIGHT INTO EARLY SUNDAY MORNING.
&&
.SHORT TERM /SUNDAY/...
THE COLD FRONT SHOULD BE MOVING THROUGH MY SERN ZONES BY EARLY
SUNDAY MORNING. COLDER AIR WILL BEGIN FILTERING INTO THE STATE
DURING THE DAY...BUT NOT BEFORE WE SEE SOME OF THE MILDEST DAYTIME
HIGHS WE HAVE SEEN IN A WHILE.
PRECIPITATION WILL TAPER OFF TO THE USUAL POST COLD FRONTAL SNOW
SHOWERS WHICH WILL MAINLY FAVOR WESTERN AND NORTHERN HIGH TERRAIN.
ACCUMS IF ANY WILL BE LIGHT AND INCONSEQUENTIAL.
FOR WHAT IT`S WORTH...THE OPERATIONAL GFS LOOKS WAY TOO WET WITH
THE LARGE AREA OF LIGHT QPF IT KEEPS HANGING AROUND OVER WESTERN
AREAS ALL DAY. I PREFER THE DRIER/LOWER GEFS POPS.
&&
.LONG TERM /SUNDAY NIGHT THROUGH FRIDAY/...
THE LAST WEEK OF THE MONTH LOOKS TO BE A COLD ONE AS AT LEAST TWO
SEPARATE ARCTIC AIRMASSES ARE POISED TO INFLUENCE OUR WEATHER.
THE FIRST CHUNK OF COLD AIR WILL BE MOVING IN BEHIND THE SYSTEM
SLATED TO AFFECT US TODAY...WITH TEMPERATURES BY MONDAY MORNING
RETURNING TO THE ALL TOO FAMILIAR FRIGID LEVELS WE HAVE
EXPERIENCED RECENTLY.
HIGH PRESSURE WILL MOVE EAST OF THE AREA BY TUESDAY PAVING THE WAY
FOR ANOTHER CLIPPER LOW AND ARCTIC AIRMASS. THE FRONTAL TIMING IS
DIFFERENT BETWEEN THE OPERATIONAL ECMWF AND GFS...BUT BOTH DRAG
THE FRONT THROUGH SOME TIME WEDNESDAY BRINGING STILL MORE DEEP
WINTER CHILL TO THE AREA TO LAST THROUGH LATE WEEK.
THE GOOD NEWS...THE NW FLOW ALOFT AND DEEP ARCTIC CHILL WILL
SUPPRESS ANY SIGNIFICANT STORMINESS SOUTH OF THE REGION.
&&
.AVIATION /15Z SATURDAY THROUGH WEDNESDAY/...
HIGH PRES MOVING EAST OF PA CONTINUES TO PROVIDE VFR FLYING CONDS
FOR A FEW MORE HOURS AT MOST TAF SITES. BUT CLOUDS ARE THICKENING
AHEAD OF A STORM SYSTEM EXPECTED TO LIFT NORTHWARD INTO THE OHIO
VALLEY BY THIS EVENING. SNOW SPREADING EASTWARD AHEAD OF THIS
SYSTEM WILL LEAD TO RAPIDLY DETERIORATING VSBYS AND CIGS THIS
MORNING IN THE WEST INTO EARLY AFTERNOON ACROSS THE EAST.
LATEST RADAR IMAGERY AND SFC OBS SHOW SNOW MOVING INTO WESTERN
PA. BASIC EXTRAPOLATION AND MESO MODEL SIMULATED RADAR SUGGEST
STEADY SNOW WILL REACH KJST AND KBFD BETWEEN 13Z-15Z...KUNV
AND KIPT BETWEEN 14Z-16Z AND KMDT/KLNS BTWEEN 15Z-17Z. WIDESPREAD
IFR/LIFR CONDS IN SNOW APPEAR VERY LIKELY ACROSS ALL OF CENTRAL PA
THRU AT LEAST EARLY SAT EVENING. THE HEAVIEST SNOW AND LOWEST
VSBYS WILL BE ACROSS THE SOUTHERN PART OF THE STATE.
SNOW ACROSS THE NORTH AND MIXED PRECIP OVER THE SOUTH WILL LIKELY
TAPER OFF SAT NIGHT...AS THE LOW PRES SYSTEM PASSES NORTH OF PA.
HOWEVER...LOW CIGS MAY STILL BE PRESENT THRU DAWN IN LOW CIGS AND
REDUCED VSBYS IN FOG AND DRIZZLE.
OUTLOOK...
SUN...AM SHRASN/LOW CIGS POSSIBLE...ESP KJST/KMDT/KLNS.
MON...NO SIG WX EXPECTED.
TUE...SNOW SHOWERS/REDUCED VSBYS POSS W MTNS TUE NIGHT.
WED...AM SNOW SHOWERS/REDUCED VSBYS POSS W MTNS.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
WINTER STORM WARNING UNTIL 7 AM EST SUNDAY FOR PAZ017>019-
024>028-033>036-042-045-046-049>053-056>059-063>066.
WINTER WEATHER ADVISORY UNTIL 7 AM EST SUNDAY FOR PAZ004>006-
010>012-037-041.
&&
$$
SYNOPSIS...LA CORTE/STEINBUGL
NEAR TERM...STEINBUGL
SHORT TERM...LA CORTE
LONG TERM...LA CORTE
AVIATION...GARTNER
AREA FORECAST DISCUSSION
NWS GREENVILLE-SPARTANBURG SC
1013 AM EST SAT FEB 21 2015
.SYNOPSIS...
A COLD FRONT WILL APPROACH FROM THE WEST TODAY AND WILL CROSS THE
REGION TONIGHT. AN ARCTIC COLD FRONT WILL MOVE ACROSS THE REGION
LATE SUNDAY WITH VERY COLD HIGH PRESSURE RETURNING EARLY NEXT WEEK.
CONDITIONS MAY REMAIN UNSETTLED THROUGH MID TO LATE WEEK AS A MOIST
SURFACE BOUNDARY LINGERS TO THE SOUTH.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 1000 AM EST...RADAR RETURNS FILLED BACK IN ACROSS THE NRN HALF
OF GA THIS MORNING...BUT SFC OBS HAVE MOSTLY 6 TO 9 KFT CLOUD BASES
WITH ONLY LIGHT PRECIPITATION REACHING THE GROUND IN A FEW SPOTS. IN
ADDITION...THE LATEST HRRR HAS THE BAND OF PRECIP DECAYING AS IT
MOVES EAST THROUGH LATE MORNING/EARLY AFTN. THUS PLAN NO EXPANSION
TO THE CURRENT WINTER WEATHER ADVISORY. HAZARD PRODUCTS APPEAR
ADEQUATELY PLACED THROUGHOUT AS MANY NC MTN AND FOOTHILL LOCATIONS
HAVE HAD AN ACCUMULATING MIXED BAG...BUT SOME DRYING IN PROFILES IS
STILL ANTICIPATED EAST OF THE MTNS. JUST ABOUT ANYONE COULD SEE A
BRIEF PERIOD OF SLEET WITH ANY SHOWERS THAT PASS OVERHEAD...BUT ANY
ACCUMULATING SNOW...SLEET...ICE SHOULD BE CONFINED TO ADVISORY OR
WARNING LOCATIONS THROUGH LATE DAY.
FOR TONIGHT...THE MODELS ARE IN GOOD AGREEMENT WITH
FINALLY MOVING THE FRONTAL ZONE EASTWARD...SO PRECIP PROBABILITIES
GRADUALLY RAMP UP FROM THE WEST WITH LIKELY/CATEGORICAL LOOKING LIKE
A GOOD BET. TEMPS WILL ACTUALLY WARM A BIT OVERNIGHT...WITH ONLY
RAIN EXPECTED ACROSS THE WHOLE FCST AREA DURING THE PERIOD OF BEST
QPF.
&&
.SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/...
AS OF 300 AM EST SATURDAY...THE SHORT TERM FCST PERIOD INITIALIZES
SUNDAY MORNING AMIDST ONGOING SURFACE FROPA. BROAD LONGWAVE UPPER
TROF CENTERED OVER THE CENTRAL/EASTERN CONUS WILL DOMINATE WITH
QUASIZONAL FLOW AROUND THE TROF BASE OVER THE SOUTHERN
APPALACHIANS. ABOVE MENTIONED SURFACE COLD FRONT WILL SLIDE THROUGH
THE REGION DURING THE MORNING HOURS WITH A BAND OF PREFRONTAL
PRECIP OUT AHEAD. THERMAL PROFILES AT THE TIME WILL BE TOO WARM FOR
ANY WINTRY PTYPE CONCERNS THEREFORE FCST FEATURES SOLID LIKELY LEVEL
POPS AT INITIALIZATION FOR RAIN...BEFORE TAPERING DOWN TO SLIGHT
CHANCE LEVELS THROUGH THE AFTERNOON INTO THE EVENING AS THE
FROPA/CAA OCCUR. SLIGHTLY HIGHER POPS WILL RESIDE OVER THE NC
MOUNTAINS SUNDAY NIGHT AS BRIEF SHOT OF NORTHWEST FLOW MOISTURE
AMONGST FALLING SNOW LEVELS COULD LEAD TO MINOR BOUTS OF SNOWFALL.
THE FRONTAL BOUNDARY SLOWS INTO MONDAY LEADING TO LINGERING LOW END
POPS SOUTH OF INTERSTATE 85 WHERE PROFILES SUPPORT ALL RAIN
PROCESSES. MEANWHILE...SURFACE HIGH PRESSURE SLIDING THROUGH THE OH
VALLEY WILL SLIDE EAST ATOP THE CENTRAL APPS THROUGH THE DAY ON
MONDAY YIELDING BRIEF CAD WEDGE REGIME DEVELOPMENT ON THE LEE SIDE OF
THE APPS INTO THE NIGHTTIME HOURS. ADDITIONALLY...GULF COASTAL
WAVE DEVELOPMENT WILL SPREAD MOISTURE NORTHWARD YIELDING UPGLIDE
INDUCED PRECIP ATOP THE ABOVE MENTIONED INTRUDING WEDGE BOUNDARY.
THEREFORE THE SHORT TERM CONCLUDES WITH DRY FCST REGIONWIDE LATE DAY
MONDAY BEFORE SLIGHT CHANCE POPS ARE REINTRODUCED INTO TUESDAY
MORNING ACROSS THE MTNS. MODEL SOUNDINGS AT THAT TIME INDICATE ALL
SNOW SUPPORTIVE PROFILES THUS THE FCST HIGHLIGHTS LIGHT SNOW
SHOWERS. TEMPERATURES THROUGH THE SHORT TERM WILL RETURN TO NEAR
NORMAL LEVELS ON SUNDAY DUE WAA REGIME AHEAD OF THE FRONT AND NON
DIURNAL TRENDS DURING THE MID/LATE MORNING. BEHIND THE FRONT ON
MONDAY EXPECTING TEMPERATURES TO FALL BACK TO NEARLY 10 DEGREES
BELOW NORMAL.
&&
.LONG TERM /TUESDAY THROUGH FRIDAY/...
AS OF 330 AM EST SATURDAY...THE MEDIUM RANGE FCST PERIOD INITIALIZES
TUESDAY MORNING WITH SLIGHT CHANCE POPS PRESENT ALONG THE MTNS OF
WESTERN NC AND NORTHEAST GA DUE TO WEAK UPGLIDE ATOP INTRUDING WEDGE
BOUNDARY. SAID UPGLIDE WILL BE FORCED BY A DEVELOPING GULF COAST
WAVE WHICH IS ACTUALLY FAIRLY CONSISTENT IN BOTH THE ECMWF/GFS.
DIFFERENCES DO ARISE WITH THE EVENTUAL NORTHWARD EXTEND OF THE
PRECIP ASSOCIATED WITH THIS WAVE...WITH THE ECMWF BEING THE MOST
AGGRESSIVE. MEANWHILE...THE GFS FAVORS PASSAGE OF A SURFACE
TROF/COLD FRONT ON TUESDAY NIGHT WITH MODEST NW H85 FLOW BANKING UP
AGAINST THE WESTERN SLOPES OF THE NC MTNS...THUS FAVORING NWFS
REGIME. THEREFORE THE FCST FEATURES A BLEND OF THE TWO WITH POPS
INCREASING TUESDAY NIGHT ACROSS THE FCST AREA FROM THE SOUTH WITH AN
ADDITIONAL INCREASE ALONG THE SPINE OF THE APPS FOR ABOVE MENTIONED
NWFS POSSIBILITIES. THUS BY WEDNESDAY NIGHT SOLID SLIGHT CHANCE
POPS ARE FAVORED REGIONWIDE WITH THE EXCEPTION OF THE NW PIEDMONT
DUE TO FURTHEST PROXIMITY TO THE SOUTHERN STREAM LOW. THERMAL
PROFILES AT THE TIME WILL BE COLD ENOUGH TO SUPPORT SNOWFALL TUESDAY
NIGHT BEFORE LOW LEVEL WARMING PREVAILS ON WEDNESDAY LEADING TO ALL
RAIN WITH THE EXCEPTION OF THE HIGHER ELEVATIONS WHERE SNOW SHOWERS
REMAIN IN THE FCST. MODEL QPF REMAINS LIGHT DURING THIS TIME SO
ACCUMULATIONS REMAIN MINIMAL AT BEST.
MOVING ALONG INTO THURSDAY...MODELS FAVOR A QUICK CHANGEOVER BACK TO
SNOW INTO THE MID MORNING HOURS BEFORE ALL POPS ARE REMOVED ACROSS
THE REGION. FROM THAT POINT FORWARD MODELS CONTINUE TO SUGGEST
SURFACE CYCLOGENESIS BY LATE WEEK AND INTO THE WEEKEND WHILE A
SUBSTANTIAL 1040MB SURFACE HIGH SETS UP ATOP NEW ENGLAND. MODELS
DISAGREE AT THIS RANGE REGARDING TIMING OF ISENTROPIC UPGLIDE PRECIP
ONSET DUE TO POTENTIAL CAD WEDGE INTRUSION AS THE GFS IS ABOUT
6-12 HOURS AHEAD OF THE ECMWF WITH PRECIP SPREADING NORTHWARD INTO
THE REGION FRIDAY NIGHT INTO SATURDAY MORNING IN THE FORM RAIN AHEAD
OF A QUICK TRANSITION TO SNOW. THIS WILL BE HIGHLY DEPENDENT ON THE
TIMING OF PRECIP ONSET...AND AT THIS RANGE...LITTLE CONFIDENCE
RESIDES IN THE CURRENT MODEL PROGS DUE TO ABOVE MENTIONED TIMING
DISCONTINUITIES. TEMPERATURES THROUGH THE MEDIUM RANGE WILL REMAIN
BELOW NORMAL AS PRIMARY UPPER BROAD SCALE TROF PERSISTS OVER THE
EAST/CENTRAL CONUS.
&&
.AVIATION /15Z SATURDAY THROUGH WEDNESDAY/...
AT KCLT...THE MORNING BAND OF LIGHT PRECIPITATION HAS LARGELY MISSED
KCLT. HOWEVER...MOIST UPGLIDE AT LOW LEVELS WILL STILL YIELD MVFR
CIGS FOR A COUPLE OF HOURS INTO THE EARLY AFTERNOON.
OTHERWISE...WILL RIDE ON A VCSH MENTION FOR ANY SPOTTY LIGHT
SLEET...WITH A TRANSITION BACK TO VFR AFTER 18Z. LOWER CIGS WILL
FILL BACK IN TONIGHT AS THE DEEPER MOISTURE BAND WITH THE COLD FRONT
ARRIVES...BUT TEMPS SHOULD BE SOLIDLY ABOVE FREEZING AT THAT POINT.
EXPECT MAINLY SE TO S WINDS LESS THAN 10 KT.
ELSEWHERE OUTSIDE THE MTNS...VFR EXPECTED THROUGH THE DAYTIME
PERIOD. KHKY WILL SEE THE BEST CHANCE OF LIGHT SNOW OR SLEET...BUT
THE CHANCES WILL WANE THROUGH THE DAY AS DRIER AIR ARRIVES FROM THE
S. ANTICIPATE A RETURN TO MVFR AND THE IFR OVERNIGHT AS THE BETTER
MOISTURE ARRIVES WITH THE COLD FRONT...BUT WITH ALL LIQUID PTYPES BY
THEN. WINDS SHOULD STAY SSE TO SW.
AT KAVL...LIGHT SN OR PL WILL FALL AT TIMES IN THE WEAK UPGLIDE OVER
THE MTNS TODAY. ANY PRECIP COULD BRIEFLY TAKE CIGS DOWN TO
MVFR...BUT MAINLY VFR IS EXPECTED. THERE IS ALSO A SMALL CHANCE OF
FZRA LATE. A STRENGTHENING LOW LEVEL JET WILL BRING LOW LEVEL WIND
SHEAR OVERHEAD STARTING AROUND MIDDAY. TEMPS SHOULD WARM UP ENUF
SUCH THAT ONLY RAIN IS EXPECTED FROM LATE AFTERNOON
ONWARD...ESPECIALLY INTO TONIGHT WHEN THE BETTER QPF WITH THE COLD
FRONT AND LOWER RESTRICTIONS RETURN.
OUTLOOK...UNSETTLED WEATHER WILL CONTINUE SUNDAY AS A COLD FRONT
MOVES SE OVER THE CAROLINAS. RESTRICTIONS ARE LIKELY. TEMPERATURES
SHOULD BE WARM ENUF THAT ONLY RAIN IS EXPECTED. ADDITIONAL WAVES OF
LOW PRESSURE MAY MOVE ALONG A FRONT STALLED OFF THE SE COAST THROUGH
MOST OF NEXT WEEK...BUT THE CONFIDENCE IN ANY OF THESE WAVES PASSING
CLOSE ENUF TO RAISE ANY RESTRICTIONS IS LOW.
CONFIDENCE TABLE...
13-19Z 19-01Z 01-07Z 07-12Z
KCLT HIGH 95% HIGH 100% HIGH 100% HIGH 100%
KGSP HIGH 100% HIGH 100% HIGH 100% HIGH 100%
KAVL MED 74% HIGH 100% HIGH 100% HIGH 100%
KHKY MED 77% HIGH 100% HIGH 100% HIGH 100%
KGMU HIGH 100% HIGH 100% HIGH 100% HIGH 100%
KAND HIGH 100% HIGH 100% HIGH 100% HIGH 100%
THE PERCENTAGE REFLECTS THE NUMBER OF GUIDANCE MEMBERS AGREEING
WITH THE SCHEDULED TAF ISSUANCE FLIGHT RULE CATEGORY. COMPLETE HOURLY
EXPERIMENTAL AVIATION FORECAST CONSISTENCY TABLES AND ENSEMBLE FORECASTS
ARE AVAILABLE AT THE FOLLOWING LINK: (MUST BE LOWER CASE)
WWW.WEATHER.GOV/GSP/AVIATION_TABLES
&&
.GSP WATCHES/WARNINGS/ADVISORIES...
GA...WINTER WEATHER ADVISORY UNTIL 8 PM EST THIS EVENING FOR GAZ010-
017-018.
NC...WINTER WEATHER ADVISORY UNTIL 8 PM EST THIS EVENING FOR
NCZ035>037-048-051>053-056>059-062>065-068-069-501>510.
WINTER STORM WARNING UNTIL 8 PM EST THIS EVENING FOR NCZ033-
049-050.
SC...WINTER WEATHER ADVISORY UNTIL 8 PM EST THIS EVENING FOR
SCZ001>003.
&&
$$
SYNOPSIS...PM
NEAR TERM...HG/PM
SHORT TERM...CDG
LONG TERM...CDG
AVIATION...HG/PM
AREA FORECAST DISCUSSION
NWS NASHVILLE TN
848 AM CST SAT FEB 21 2015
.MESOSCALE UPDATE...
ICE ACCUMULATIONS AROUND 1 INCH ALONG PLATEAU WILL LET ICE STORM
WARNING EXPIRE AT 9 AM CST BUT WILL ISSUED SPS TO MENTION TEMPS
NOW ABOVE FREEZING MOST AREAS...BUT STILL COULD BE ISOLATED
LOCATIONS WHERE TEMPS ARE RIGHT AT 32 DEGREES BUT WILL RISE ABOVE
FREEZING WITHIN THE NEXT HOUR OR TWO. WE`VE HAD REPORTS OF 1/2 TO
1 INCH OF ICE ALONG THE PLATEAU OVERNIGHT WITH SOME POWER OUTAGES
AND SNAPPING BRANCHES BEING REPORTED. HAVE SOME CONCERN FOR GUSTY
WINDS SINCE LATEST RUC SHOWING TIGHT PRESSURE GRADIENT BETWEEN
TENNESSEE RIVER AND EASTERN TENNESSEE. COULD ALSO SEE STRONGER
ISALLOBARIC WINDS AT TIMES THIS MORNING. SURFACE LOW CENTERED TO
OUR SOUTHWEST NEAR TEXARKANA WITH WARM FRONT STRETCHED FROM LOW UP
INTO KENTUCKY...NORTH OF MID STATE. LOW LEVEL JET THE STRONGEST
I`VE EVEN SEEN AT 850 MBARS...86 KNOTS OFF 12Z OHX RAOB. THAT
MEANS PLENTY OF LOW LEVEL WARM ADVECTION PUMPING UP INTO MIDDLE
TENNESSEE NEXT SEVERAL HOURS. WITH TOTAL TOTALS AT 51 WE COULD SEE
ISOLATED THUNDERSTORMS EMBEDDED A MUCH LARGER RAIN AREA DURING THE
DAY. 0-3 STORM RELATIVE HELICITY 1862 M2/S2. SWEAT INDEX AT 453.
LOOKS LIKE 2 TO 4 INCH RAIN TOTALS WITH UP TO 5 INCHES AND
POSSIBLY A A LITTLE MORE OVER THE NORTHWEST THROUGH NOON SUNDAY.
PONDING OF WATER ON ROADWAYS WILL BE AN ISSUE WITH ICE DAMMING
OCCURRING.
&&
.OHX WATCHES/WARNINGS/ADVISORIES...
FLOOD WATCH THROUGH SUNDAY MORNING FOR TNZ005>011-023>034-
056>066-075-077>080.
ICE STORM WARNING UNTIL 9 AM CST THIS MORNING FOR TNZ010-011-
031>034-065-066-077>080.
&&
$$
BOYD
01
AREA FORECAST DISCUSSION
NWS SAN ANGELO TX
955 PM CST Sun Feb 22 2015
.UPDATE...
Based on radar data, it appears we`re in a bit of a lull across
the area now. However, calls across the CWA and automated surface
observations indicate that widespread, light freezing drizzle is
occurring in many areas. Temperatures continue to run a few
degrees below even the coldest guidance, with current readings in
the 20s everywhere excluding the I-10 corridor (lower 30s).
Temperatures will continue to slowly drop tonight, setting
the stage for the next shortwave trough.
The primary wave looks to be moving across the northern Baja
Peninsula at this time, with notable forced ascent downstream
over AZ, NM, and northern Mexico. There is a band of frontogenetic
forcing sloping up and over the cold dome from north to south that
is progged to persist into Monday morning before weakening. This
area of mesoscale lift should be enhanced by the approaching
shortwave energy. The going forecast looks to be in relatively
good shape. The wx grids were modified for this evening, with
widespread drizzle and only a chance for sleet mentioned areawide.
However, after midnight, we expect additional precipitation to
develop.
Point soundings suggest the favored precipitation types to be
sleet and freezing rain. However, both the NAM and RAP soundings
show the cold near surface layer (below the inversion) to be near
-10C. While this generally favors supercooled liquid hydrometeors,
this is a borderline temperature for the activation of ice nuclei.
This would account for the very light snow we`ve had reported over
the past few hours. Expect snow accumulations to be a dusting or
less. With elevated instability in place, this precipitation
should be more convective in nature, with the potential for
thundersleet overnight. In areas that do experience thunder, the
enhanced convective updrafts may lead to localized higher amounts
of sleet and/or snow.
Precipitation is expected to diminish by Monday afternoon,
although freezing drizzle will remain possible even into Monday
evening. Expect surface temperatures on Monday to remain well
below freezing, with highs in the mid/upper 20s. There may be just
enough radiation coming through the thick overcast to improve road
surfaces on Monday, but most of the ice should persist into
Tuesday morning.
Johnson
&&
.PREV DISCUSSION... /ISSUED 514 PM CST Sun Feb 22 2015/
AVIATION...
/00Z TAFS/
Generally LIFR/IFR conditions are being experienced at all sites
this evening and are forecast to continue through the next 24
hours. Light freezing drizzle continues at KABI and is forecast
to develop at KSJT around 00z as temperatures drop to or below
freezing. Light drizzle will continue at the other sites then
transition to light freezing drizzle late this evening as
temperatures drop below freezing. Areas of light freezing
rain/sleet may develop after midnight, mainly at KABI and KSJT.
Northeast winds of 12 to 20 knots, with higher gusts, will
decrease to 8 to 12 knots by late morning Monday.
PREV DISCUSSION... /ISSUED 409 PM CST Sun Feb 22 2015/
SHORT TERM...
(Tonight through Tuesday morning)
The much talked about winter storm is beginning to affect the
area. Another cold front was crossing the area at 3 PM and was
located along an Ozona to just south of Brownwood line, with cold
air rapidly invading the area behind this front. Trends in the
observations are showing temperatures dropping 5 to 10 degrees per
hour behind it. In fact, many areas along/north of Interstate 20
have already dropped below freezing with freezing rain, sleet, and
ice accumulations already occurring per social media, phone calls,
and observations. Given these developments over the last few
hours, and after coordinating with surrounding offices, the Winter
Storm Warning start time has been increased to 4 PM this
afternoon.
Things continue to look like they`ll get messy through tomorrow.
The numerical models remain consistent dropping temperatures
into the lower to mid 20s across the warned area, and near
freezing farther south, with not much recovery tomorrow afternoon.
They have also trended stronger/farther south with their
convective signature. The Storm Prediction Center has most of West
Central Texas in a risk for thunder tonight/tomorrow and model
soundings show 100-250 J/kg of MUCAPE across the entire forecast
area during this period. As a result, thunder was included in all
zones for tonight through mid afternoon tomorrow.
LONG TERM...
(Tuesday through Sunday)
All hands on board for the first winter storm, so this part of the
discussion will be brief. Warming trend starts on Tuesday
afternoon, although it will be modest. A few breaks in the clouds
will allow a little sun, enough to allow temperatures to climb
into the 40s. Another upper level low will drop into the southwest
US, with return flow ahead of it allowing readings to climb into
the 60s on Wednesday. Next arctic front moves across the area for
Thursday and Friday, just ahead of the upper level trough moving
across. GFS and the ECMWF have some differences in the strength of
this system, with the GFS shearing it out a little faster. For
now, kept the compromise intact and have slight chance to chance
PoPs across the area. Models did warm just a tad, so was able to
shift the mention of snow a little farther north.
&&
.PRELIMINARY POINT TEMPS/POPS...
Abilene 21 25 20 40 29 / 90 80 10 10 5
San Angelo 25 29 25 46 31 / 90 70 10 10 5
Junction 29 32 28 48 34 / 80 70 10 10 10
&&
.SJT WATCHES/WARNINGS/ADVISORIES...
WINTER STORM WARNING until 6 PM CST Monday FOR THE FOLLOWING
ZONES: Brown...Callahan...Coke...Coleman...Concho...Fisher...
Haskell...Irion...Jones...Nolan...Runnels...Shackelford...
Sterling...Taylor...Throckmorton...Tom Green.
WINTER WEATHER ADVISORY until 6 PM CST Monday FOR THE FOLLOWING
ZONES: Crockett...Kimble...Mason...McCulloch...Menard...San
Saba...Schleicher...Sutton.
&&
$$
25
AREA FORECAST DISCUSSION...UPDATED
NWS FORT WORTH TX
939 PM CST SUN FEB 22 2015
.UPDATE...
AS THE FIRST WAVE OF PRECIPITATION ENDS THIS EVENING...A LARGE
AREA OF FREEZING DRIZZLE HAS DEVELOPED NORTH TO WEST OF THE DFW
METROPLEX INCLUDING TARRANT COUNTY. 850 MB WINDS ARE OUT OF THE
EAST OVERRUNNING THE COLD SURFACE AIR...BUT THEY HAVE PREVAILED
FROM THIS DIRECTION MOST OF THE EVENING WITHOUT DRIZZLE
DEVELOPING EARLIER IN THE NIGHT. THE RAP SHOWS A WEAK SHORTWAVE
MOVING OVERHEAD WHICH IS LIKELY PROVIDING ADDITIONAL LIFT FOR THE
DRIZZLE TO DEVELOP...IN COMBINATION WITH THE ISENTROPIC LIFT OVER
THE COLD SURFACE LAYER. THE RAP SHOWS THIS SHORTWAVE MOVING EAST
OF THE REGION BY MIDNIGHT AND EXPECT MOST OF THE DRIZZLE WILL END
AROUND THAT TIME. HOWEVER...THE DRIZZLE IS ALREADY AND WILL
CREATE A THIN LAYER OF ICE ON ELEVATED SURFACES...METAL
OBJECTS...AND LIKELY BRIDGES AND OVERPASSES THAT ALREADY DO NOT
HAVE ICE FROM THE FREEZING RAIN/SLEET EARLIER. IN
ADDITION...RESIDUAL WATER REMAINING ON ROADWAYS TONIGHT MAY FREEZE
OVERNIGHT AS TEMPERATURES FALL INTO THE 20S OVER A GOOD PORTION OF
THE REGION. HOWEVER...THE STRONG WINDS WILL CONTINUE THROUGH THE
OVERNIGHT HOURS WHICH MAY ALSO HELP TO EVAPORATE ANY WATER ON
ROADWAYS...BUT NOT WHERE DRIZZLE IS OCCURRING.
THE NEXT WAVE OF PRECIPITATION IS STILL EXPECTED TO ARRIVE BETWEEN
1-3 AM...MOVING IN FROM THE WEST OR SOUTHWEST. NO CHANGES ARE
NEEDED TO THE CURRENT WARNING AND ADVISORY PRODUCTS...HOWEVER...IF
THE NEXT ROUND OF PRECIPITATION IS SLIGHTLY FARTHER SOUTH THAN THE
LATEST GUIDANCE SUGGESTS...IT IS POSSIBLE PORTIONS OF THE ADVISORY
MAY HAVE TO BE UPGRADED TO A WARNING DUE TO HIGHER ACCUMULATIONS
OF SLEET. UNFORTUNATELY WE WILL HAVE TO WAIT AND MONITOR THE RADAR
TRENDS LATE TONIGHT AND EARLY MONDAY MORNING BEFORE BEING ABLE TO
CONFIDENTLY MAKE THAT DECISION.
82/JLD
&&
.AVIATION...
/ISSUED 606 PM CST SUN FEB 22 2015/
SOME CHANGES WERE NECESSARY TO THE PREVIOUS TAF PACKAGE BASED ON
HOW QUICKLY TEMPERATURES CONTINUE TO FALL. A MIX OR FREEZING
RAIN/RAIN AND SLEET HAS ALREADY STARTED AT AFW AND FTW AND SHOULD
START AT DFW...GKY...AND DAL IN THE NEXT FEW HOURS. (THE -SN IN
THE GKY OB IS NOT CORRECT...IT IS ACTUALLY STILL LIGHT RAIN AS OF
6 PM). 00Z FWD SOUNDING SHOWS AN IMPRESSIVE WARM NOSE BETWEEN
ABOUT 850 AND 700 MB WITH VERY UNSTABLE AIR ABOVE THIS INVERSION.
THEREFORE...THE ATMOSPHERE IS CONDUCIVE TO CONVECTIVE ELEMENTS SO
PERIODS OF HEAVY SLEET ALONG WITH THUNDER REMAIN POSSIBLE. FOR NOW
WE WILL CHANGE PRECIP OVER TO A MIX OF FREEZING RAIN AND SLEET AT
ALL METROPLEX TERMINAL BETWEEN NOW AND 02Z. IFR
CEILINGS/VISIBILITY WILL PREVAIL THROUGH THE NIGHT WITH A NORTH
WIND BETWEEN 14 AND 18 KNOTS ALONG WITH SOME HIGHER GUSTS.
THE WINTER PRECIPITATION SHOULD DECREASE IN COVERAGE AND INTENSITY
MID TO LATE EVENING WITH MAINLY LIGHT FREEZING DRIZZLE EXPECTED. A
SECOND PIECE OF UPPER LEVEL ENERGY WILL MOVE ACROSS THE REGION
BEGINNING EARLY MONDAY MORNING AND BRING ANOTHER ROUND OR MAINLY
SLEET. THIS PRECIPITATION SHOULD CONTINUE OFF AND ON THROUGH THE
MORNING MONDAY BEFORE ENDING FROM WEST TO EAST MONDAY AFTERNOON
AND EVENING. IFR WITH OCCASIONAL MVFR CEILINGS/VISIBILITIES WILL
PREVAIL THROUGH THE DAY MONDAYS WITH SLOWLY DECREASING NORTH
WINDS.
WACO SHOULD SEE IFR WITH OCCASIONAL MVFR CIGS/VISIBILITY TONIGHT
WITH PERIODS OF DRIZZLE OR LIGHT RAIN. SOME LIGHT FREEZING
DRIZZLE IS POSSIBLE AROUND SUNRISE MONDAY WITH LIGHT FREEZING RAIN
AND SLEET POSSIBLE FROM ABOUT MID MORNING MONDAY THROUGH THE
AFTERNOON.
79
&&
.PREV UPDATE...
.UPDATE...
HAVE UPDATED THE GRIDS FOR THE 00-06Z TIME FRAME BASED ON THE
LATEST RADAR AND WEATHER TRENDS. A WINTER PRECIPITATION MIX OF
RAIN/SLEET/FREEZING RAIN AND EVEN SOME SNOW IS OCCURRING
GENERALLY NORTH OF A LINE FROM COMANCHE TO FORT WORTH TO BONHAM
AND SURFACE TEMPERATURES IN THIS AREA RANGE FROM THE MID 20S IN
THE NORTHWEST TO 32 DEGREES. SHORT TERM GUIDANCE CONTINUES TO
SUGGEST THIS FIRST WAVE OF PRECIPITATION WILL END ACROSS THE
REGION BETWEEN 9 PM - MIDNIGHT WITH SOME ISOLATED LIGHT LINGERING
PRECIP AFTER THAT. THE NEXT WAVE OF PRECIPITATION WILL ARRIVE
AROUND 2-3 AM IN OUR SOUTHWESTERN COUNTIES...MOVING NORTHEAST
ACROSS THE REGION.
ACCUMULATIONS OF ICE AND SLEET ARE ALREADY BEING REPORTED WITHIN
THE HIGHLIGHTED AREA ABOVE AND IMPACTS TO TRAVEL ARE BEING
REPORTED ALONG THE RED RIVER. AS FAR SOUTH AS THE NORTHERN
PORTIONS OF THE METROPLEX...SOME SLUSHY ROADS AND SLICK BRIDGES
AND OVERPASSES ARE ALREADY BEING REPORTED WHERE MODERATE TO HEAVY
SLEET OCCURRED IN THE LAST 2-3 HOURS. AS TEMPERATURES CONTINUE TO
FALL THROUGH THE NEXT FEW HOURS...TRAVEL WITHIN THE WARNING AREA
ESPECIALLY WILL BECOME MORE DIFFICULT...NOT ONLY FROM THE FREEZING
RAIN AND SLEET THAT IS OCCURING IN THIS AREA...BUT ANY WATER THAT
IS LEFT ON THE ROADWAYS DUE TO THE RAIN EARLIER COULD POSSIBLY
FREEZE RESULTING IN A THIN GLAZE OF ICE ON ROADWAYS.
82/JLD
&&
.PREV DISCUSSION... /ISSUED 400 PM CST SUN FEB 22 2015/
...SIGNIFICANT WINTER STORM TAKING SHAPE FOR OVERNIGHT AND EARLY
MONDAY ACROSS NORTH TEXAS...
.SIGNIFICANT FORECAST CHANGES...
WINTER STORM WARNING START TIME HAS BEEN MOVED UP TO START NOW.
WINTER WEATHER ADVISORY START TIME HAS BEEN MOVED UP TO 9PM.
SLEET ACCUMULATIONS HAVE BEEN BUMPED UP SLIGHTLY ACROSS THE
NORTHWEST PARTS OF THE CWA. ICE ACCUMULATIONS FROM FREEZING RAIN
HAVE BEEN NUDGED UP SLIGHTLY BUT REMAIN BELOW WARNING CRITERIA
FARTHER SOUTH. HOURLY TEMPERATURE TRENDS HAVE BEEN ADJUSTED TO
REFLECT CURRENT POSITION OF COLDER AIR. HIGH TEMPERATURES ON
MONDAY HAVE BEEN LOWERED BY 2-3 DEGREES. NO OTHER SIGNIFICANT
FORECAST CHANGES THIS AFTERNOON.
.TECHNICAL DISCUSSION...
MUCH COLDER AIR CONTINUES TO FILTER INTO NORTH TEXAS THIS
AFTERNOON WITH SUB FREEZING TEMPERATURES NOW MOVING INTO THE
NORTHWEST COUNTIES. PRECIPITATION HAS DIMINISHED IN INTENSITY
ACROSS THESE AREAS WHICH SHOULD LIMIT ANY FREEZING RAIN POTENTIAL
THROUGH THE EVENING HOURS. FARTHER EAST...A COLD RAIN WILL
CONTINUE THROUGH THE EARLY EVENING AS THE FIRST WAVE OF LIFT MOVES
TO THE NORTHEAST. TEMPERATURES ARE GENERALLY IN THE MID TO UPPER
30S AND LOWER 40S WHERE THIS PRECIPITATION IS OCCURRING SO NO
FREEZING RAIN IS EXPECTED. SOME AREAS HAVE ALREADY PICKED UP CLOSE
TO AN INCH OF RAIN BUT THIS INTENSITY WILL DIMINISH THROUGH
EVENING.
SIGNS OF THE SECOND WAVE OF ASCENT ARE ALREADY BEING INDICATED ON
RADAR AND WATER VAPOR IMAGERY ACROSS WEST TEXAS. SOME AREAS OF
PRECIPITATION HAVE ALREADY DEVELOPED BUT THIS SHOULD GENERALLY
REMAIN SCATTERED OVER THE NEXT SEVERAL HOURS AS THE BETTER FORCING
WILL ARRIVE DURING THE OVERNIGHT HOURS. WE ARE EXPECTED TO SEE A
LULL IN THE PRECIPITATION LATER THIS EVENING THROUGH MIDNIGHT OR
SO...BUT IT WONT BE COMPLETELY VOID OF ACTIVITY. THERE WILL LIKELY
BE INTERMITTENT AREAS OF PRECIPITATION THAT DEVELOP IN POCKETS OF
STRONGER FORCING THAT STREAM ACROSS NORTH TEXAS IN THE SOUTHWEST
FLOW ALOFT. ANY PRECIPITATION THAT DEVELOPS LATE THIS EVENING
COULD BE IN THE FORM OF A FREEZING RAIN/SLEET MIX ACROSS THE WEST
AND NORTHWEST PARTS OF THE CWA. THE FREEZING LINE WILL SURGE SOUTH
THIS EVENING ACROSS THE WESTERN COUNTIES AND IT WILL TAKE A LITTLE
LONGER FARTHER EAST. IT SHOULD BE MOVING INTO THE METROPLEX BY 0Z
OR A LITTLE LATER. BY 3-4AM...MOST AREAS WITH THE EXCEPTION OF THE
SOUTHEAST COUNTIES SHOULD BE AT OR BELOW FREEZING.
THE STRONGEST FORCING LOOKS LIKE IT WILL OVERSPREAD NORTH TEXAS IN
THE 3-5AM TIMEFRAME WITH WIDESPREAD PRECIPITATION CONTINUING INTO
THE MORNING HOURS ON MONDAY. THE COMPACT UPPER LOW SOUTH OF
CALIFORNIA IS IN THE PROCESS OF EJECTING NORTHEAST NOW AND ANOTHER
DISTURBANCE APPEARS TO BE EMBEDDED IN THE FLOW ACROSS NORTHWEST
MEXICO. THESE SEEM TO BE THE FEATURES THAT REALLY PROVIDE THE
FORCING FOR ASCENT LATE TONIGHT. RIGHT NOW... WE THINK THE
HEAVIEST PRECIPITATION WILL OCCUR ALONG A LINE FROM NEAR EASTLAND
TO DFW TO SHERMAN...AND AREAS NORTHWEST OF THERE THROUGH ABOUT
10AM ON MONDAY. LATEST HIGH RESOLUTION TTU-WRF AND 4KM NAM
CONTINUE TO YIELD HIGH CONFIDENCE IN THE CURRENT FORECAST AS BOTH
CONTINUE TO STRONGLY INDICATE CONVECTIVE ELEMENTS TO THE
PRECIPITATION. SREF PLUMES OF MUCAPE AND ANALYSIS OF ALL AVAILABLE
FORECAST SOUNDINGS INDICATE THAT ANYWHERE FROM 100-150J/KG OF
ELEVATED INSTABILITY WILL BE PRESENT. THIS WILL SUPPORT
THUNDERSLEET THROUGH THE MORNING HOURS. BURSTS OF SLEET CAN
QUICKLY ACCUMULATE TO AN INCH OR MORE IN A SHORT PERIOD OF TIME.
AS OF THIS AFTERNOON...WE THINK THAT MOST AREAS IN THE CURRENT
WARNING WILL SEE BETWEEN 1/2 AND 1 INCH OF SLEET. FARTHER
NORTHWEST...FROM FORT WORTH TO BOWIE...ACCUMULATIONS OF 1 TO 1 1/2
INCH OF SLEET WITH HEAVIER AMOUNTS WILL BE POSSIBLE. SOME LIGHT
FREEZING RAIN WILL ALSO BE POSSIBLE THROUGH MORNING BUT ICE
ACCUMULATIONS SHOULD GENERALLY BE LESS THAN 1/10 OF AN INCH.
FARTHER SOUTH OF THE METROPLEX...WHERE THE CURRENT ADVISORY IS
POSTED...THE WARM NOSE WILL BE A LITTLE MORE STOUT INITIALLY.
THIS MAY KEEP PRECIPITATION ALL LIQUID AS OPPOSED TO SLEET. WITH
TEMPERATURES FALLING BELOW FREEZING...SOME LIGHT ICING IS
EXPECTED. THIS WILL BE WORST ON BRIDGES AND OVERPASSES. MOST OF
THE PRECIPITATION SHOULD MOVE EAST OF THE AREA BY LATE MONDAY BUT
WE WILL KEEP SOME LOW CHANCES IN THROUGH THE EVENING. SOME LIGHT
FREEZING RAIN OR DRIZZLE MAY BE POSSIBLE DURING THIS TIME WITH
LITTLE ADDITIONAL IMPACT.
TEMPERATURES ON MONDAY ARE NOT EXPECTED TO RISE ABOVE FREEZING SO
ANY ACCUMULATIONS OF SLEET/ICE WILL NOT MELT. THIS WILL RESULT IN
CONTINUED TRAVEL PROBLEMS. TEMPERATURES ARE EXPECTED TO RISE ABOVE
FREEZING BY MIDDAY TUESDAY.
LITTLE CHANGES MADE TO THE END OF THE WEEK SYSTEM AS THERE IS
STILL CONSIDERABLY MODEL UNCERTAINTY. WE HAVE CONTINUED WITH A
RAIN/SNOW MIX LATE THURSDAY INTO LATE FRIDAY ACROSS MUCH OF THE
AREA.
DUNN
&&
.PRELIMINARY POINT TEMPS/POPS...
DALLAS-FT. WORTH, TX 26 27 25 39 31 / 80 100 20 20 10
WACO, TX 30 31 24 38 33 / 80 90 30 20 30
PARIS, TX 25 25 25 36 28 / 50 100 30 20 10
DENTON, TX 23 25 20 36 29 / 80 100 10 10 10
MCKINNEY, TX 26 26 23 38 28 / 70 100 20 10 10
DALLAS, TX 28 29 26 39 31 / 80 100 20 20 10
TERRELL, TX 29 29 25 37 30 / 70 100 20 20 10
CORSICANA, TX 30 30 26 38 32 / 70 90 30 20 20
TEMPLE, TX 31 32 25 40 34 / 90 90 30 20 30
MINERAL WELLS, TX 24 25 20 36 28 / 100 100 10 10 10
&&
.FWD WATCHES/WARNINGS/ADVISORIES...
WINTER STORM WARNING UNTIL 6 PM CST MONDAY FOR TXZ091>095-
100>107-115>123-129>134-141.
WINTER WEATHER ADVISORY UNTIL 6 PM CST MONDAY FOR TXZ135-142>148-
156>162-174-175.
&&
$$
79/82
AREA FORECAST DISCUSSION...UPDATED
NWS CORPUS CHRISTI TX
626 PM CST SUN FEB 22 2015
.DISCUSSION...UPDATE SENT TO REFLECT EXPIRATION OF RIP CURRENT
ADVISORY. ROUGH SWELLS WILL CONTINUE TO GRADUALLY DIMINISH THROUGH
THE EVENING AS A STRONG COLD FRONT APPROACHES THE REGION. ALSO
MADE A FEW MINOR EDITS TO HOURLY WIND AND TEMPERATURE FORECAST
BASED OFF FROPA POSITIONING AND EXTRAPOLATION. FRONT SHOULD START
TO ACCELERATE SOUTH THIS EVENING AS NOCTURNAL COOLING OCCURS AHEAD
OF THE FRONT.
&&
.PREV DISCUSSION... /ISSUED 523 PM CST SUN FEB 22 2015/
DISCUSSION...UPDATED FOR 00Z TAF FORECAST.
AVIATION...COLD FRONT CURRENTLY JUST TO THE NORTH OF SOUTH TEXAS
WILL MOVE THROUGH ALL TAF LOCATIONS BEFORE MIDNIGHT. EXPECT A
GUSTY NORTH WIND TO DEVELOP BEHIND THE FRONT. AHEAD OF THE FRONT
IFR TO POTENTIALLY LIFR CONDITIONS WILL DEVELOP...AND REMAIN
THROUGH THE NIGHT. BY DAYBREAK...SHOULD IMPROVE CONDITIONS TO MVFR
WHERE THEY WILL REMAIN THROUGH THE DAY. LIGHT RAIN WILL BE
POSSIBLE AT TIMES AS WELL.
PREV DISCUSSION... /ISSUED 348 PM CST SUN FEB 22 2015/
SHORT TERM (TONIGHT THROUGH MONDAY NIGHT)...FRONTAL BOUNDARY HAS
REMAINED STALLED JUST NORTH OF THE FORECAST AREA THIS AFTERNOON.
LATEST MSAS ANALYSIS SHOWS AREAS OF STRONG PRESSURE RISES BEHIND
THE FRONT SHIFTING TOWARD CENTRAL TEXAS INTO THE HILL COUNTRY. THIS
CORRESPONDS TO LOCATION OF TEMPERATURES IN THE 40S. EXPECT THE FRONT
WILL BEGIN TO ADVANCE SOUTHWARD LATE THIS AFTERNOON AND SURGE TO
THE SOUTH THIS EVENING. WENT CLOSE TO THE SREF/HRRR/3KM TECH WRF
AND ECMWF WITH TIMING OF THE FRONT...PUSING INTO THE COASTAL WATERS
BETWEEN 04-06Z. HRRR SHOWS THE POSSIBILITY OF CONVECTION FORMING
OVER THE HIGH TERRAIN IN NORTHEAST MEXICO AHEAD OF THE COLD FRONT
AND MOVING SOUTHEAST TOWARD THE RIO GRANDE. BUT EXPECT AIR MASS TO
BE CAPPED AND WILL NOT MENTION THUNDER IN THE FORECAST AT THIS
TIME. THERE WILL BE A PERIOD OF FOG POSSIBLE ALONG THE COAST BEFORE
FRONTAL PASSAGE. MODEST ISENTROPIC LIFT WILL OCCUR IN THE 285-300K
LAYER LATE TONIGHT THROUGH MONDAY. WILL SHOW POPS AROUND 50 PERCENT
FOR TONIGHT WITH LIKELY POPS FOR MONDAY. LOW LEVEL COLD AIR ADVECTION
WILL CONTINUE DURING THE DAY MONDAY. DIURNAL TREND MAY BE SLOWLY
DOWNWARD MOST OF THE DAY. ISENTROPIC LIFT WILL DIMINISH FROM WEST
TO EAST MONDAY NIGHT WITH DECREASING POPS. LOW TEMPS WILL REACH
DOWN INTO THE 30S MONDAY NIGHT BUT EXPECT IT WILL REMAIN ABOVE
FREEZING AT THIS TIME.
MARINE (TONIGHT THROUGH MONDAY NIGHT)...COLD FRONT WILL REACH
THE BAYS AND NEARSHORE WATERS A LITTLE EARLIER THIS EVENING. PUT
THE START TIME FOR THE SCA FOR TONIGHT AT 04Z. STRONG NORTH TO
NORTHEAST WINDS WILL PERSIST INTO MONDAY NIGHT FOR THE GULF WATERS.
EXTENDED SCA FOR THE BAYS THROUGH THE DAY MONDAY AND MONDAY EVENING
FOR THE GULF WATERS.
LONG TERM (TUESDAY THROUGH SATURDAY NIGHT)...ZONAL FLOW ACROSS THE
SOUTHERN CONUS THIS FORECAST PERIOD WILL RESULT IN A MIX OF WEATHER
CONDITIONS FOR THIS UPCOMING WEEK. ISENTROPIC LIFT WILL MAINTAIN CHC
OF LIGHT RAIN THROUGH EARLY WEDNESDAY BEFORE DRIER AIR MOVES IN AND
A SLIGHT WARMING TREND COMMENCES. TEMPS ON TUE WILL STRUGGLE TO GET
OUT OF THE 40S DUE TO THICK CLOUD COVER...ALTHOUGH A FEW 50S ARE
POSSIBLE ALONG THE COAST AND OUT WEST. NEXT REINFORCING SURGE OF
HIGH PRESSURE ARRIVES EARLY WEDNESDAY WITH SCA CONDITIONS OCCURING
ON WED...HOWEVER...ABUNDANT SUNSHINE WILL ALLOW TEMPS TO REACH THE
60S BOTH WED-THU. NEXT FRONT ARRIVES LATE THURSDAY WITH A MODERATE
OFFSHORE FLOW DEVELOPING IN ITS WAKE. THE FRONT WILL DROP TEMPS BACK
INTO THE 40S-50S FOR FRIDAY BENEITH OVC SKIES. COULD BE A FEW
SHOWERS AS MOIST SOUTHERLY LOW LVL FLOW OVERRIDES THE COOL BOUNDARY
LAYER. THE COOL AIR WONT LAST LONG AS A DEEP TROUGH BEGINS TO TAKE
SHAPE ACROSS THE DESERT SW DRAWING A WARM FRONT BACK THROUGH THE
AREA SAT. TEMPS ON SAT WILL WARM BACK INTO THE LOW TO MID 60S SAT
WITH 70S EXPECTED SUNDAY.
&&
.PRELIMINARY POINT TEMPS/POPS...
CORPUS CHRISTI 47 48 38 50 43 / 50 70 40 20 30
VICTORIA 43 44 35 46 38 / 50 70 40 20 40
LAREDO 46 46 39 54 44 / 50 50 20 10 10
ALICE 45 46 37 50 41 / 50 70 40 20 30
ROCKPORT 47 50 39 50 43 / 50 70 40 30 40
COTULLA 42 43 35 50 40 / 50 50 30 10 10
KINGSVILLE 48 48 37 50 43 / 50 70 40 20 30
NAVY CORPUS 49 51 39 51 45 / 50 70 40 30 40
&&
.CRP WATCHES/WARNINGS/ADVISORIES...
TX...NONE.
GM...SMALL CRAFT ADVISORY FROM 10 PM THIS EVENING TO MIDNIGHT CST
MONDAY NIGHT FOR THE FOLLOWING ZONES: COASTAL WATERS FROM
BAFFIN BAY TO PORT ARANSAS OUT 20 NM...COASTAL WATERS FROM
PORT ARANSAS TO MATAGORDA SHIP CHANNEL OUT 20 NM...WATERS
FROM BAFFIN BAY TO PORT ARANSAS FROM 20 TO 60 NM...WATERS
FROM PORT ARANSAS TO MATAGORDA SHIP CHANNEL FROM 20 TO 60
NM.
SMALL CRAFT ADVISORY FROM 10 PM THIS EVENING TO 6 PM CST MONDAY
FOR THE FOLLOWING ZONES: BAYS AND WATERWAYS FROM BAFFIN BAY
TO PORT ARANSAS...BAYS AND WATERWAYS FROM PORT ARANSAS TO
PORT O`CONNOR.
&&
$$
UPDATE...HART/79
AREA FORECAST DISCUSSION
NWS CORPUS CHRISTI TX
523 PM CST SUN FEB 22 2015
.DISCUSSION...UPDATED FOR 00Z TAF FORECAST.
&&
.AVIATION...COLD FRONT CURRENTLY JUST TO THE NORTH OF SOUTH TEXAS
WILL MOVE THROUGH ALL TAF LOCATIONS BEFORE MIDNIGHT. EXPECT A
GUSTY NORTH WIND TO DEVELOP BEHIND THE FRONT. AHEAD OF THE FRONT
IFR TO POTENTIALLY LIFR CONDITIONS WILL DEVELOP...AND REMAIN
THROUGH THE NIGHT. BY DAYBREAK...SHOULD IMPROVE CONDITIONS TO MVFR
WHERE THEY WILL REMAIN THROUGH THE DAY. LIGHT RAIN WILL BE
POSSIBLE AT TIMES AS WELL.
&&
.PREV DISCUSSION... /ISSUED 348 PM CST SUN FEB 22 2015/
SHORT TERM (TONIGHT THROUGH MONDAY NIGHT)...FRONTAL BOUNDARY HAS
REMAINED STALLED JUST NORTH OF THE FORECAST AREA THIS AFTERNOON.
LATEST MSAS ANALYSIS SHOWS AREAS OF STRONG PRESSURE RISES BEHIND
THE FRONT SHIFTING TOWARD CENTRAL TEXAS INTO THE HILL COUNTRY. THIS
CORRESPONDS TO LOCATION OF TEMPERATURES IN THE 40S. EXPECT THE FRONT
WILL BEGIN TO ADVANCE SOUTHWARD LATE THIS AFTERNOON AND SURGE TO
THE SOUTH THIS EVENING. WENT CLOSE TO THE SREF/HRRR/3KM TECH WRF
AND ECMWF WITH TIMING OF THE FRONT...PUSING INTO THE COASTAL WATERS
BETWEEN 04-06Z. HRRR SHOWS THE POSSIBILITY OF CONVECTION FORMING
OVER THE HIGH TERRAIN IN NORTHEAST MEXICO AHEAD OF THE COLD FRONT
AND MOVING SOUTHEAST TOWARD THE RIO GRANDE. BUT EXPECT AIR MASS TO
BE CAPPED AND WILL NOT MENTION THUNDER IN THE FORECAST AT THIS
TIME. THERE WILL BE A PERIOD OF FOG POSSIBLE ALONG THE COAST BEFORE
FRONTAL PASSAGE. MODEST ISENTROPIC LIFT WILL OCCUR IN THE 285-300K
LAYER LATE TONIGHT THROUGH MONDAY. WILL SHOW POPS AROUND 50 PERCENT
FOR TONIGHT WITH LIKELY POPS FOR MONDAY. LOW LEVEL COLD AIR ADVECTION
WILL CONTINUE DURING THE DAY MONDAY. DIURNAL TREND MAY BE SLOWLY
DOWNWARD MOST OF THE DAY. ISENTROPIC LIFT WILL DIMINISH FROM WEST
TO EAST MONDAY NIGHT WITH DECREASING POPS. LOW TEMPS WILL REACH
DOWN INTO THE 30S MONDAY NIGHT BUT EXPECT IT WILL REMAIN ABOVE
FREEZING AT THIS TIME.
MARINE (TONIGHT THROUGH MONDAY NIGHT)...COLD FRONT WILL REACH
THE BAYS AND NEARSHORE WATERS A LITTLE EARLIER THIS EVENING. PUT
THE START TIME FOR THE SCA FOR TONIGHT AT 04Z. STRONG NORTH TO
NORTHEAST WINDS WILL PERSIST INTO MONDAY NIGHT FOR THE GULF WATERS.
EXTENDED SCA FOR THE BAYS THROUGH THE DAY MONDAY AND MONDAY EVENING
FOR THE GULF WATERS.
LONG TERM (TUESDAY THROUGH SATURDAY NIGHT)...ZONAL FLOW ACROSS THE
SOUTHERN CONUS THIS FORECAST PERIOD WILL RESULT IN A MIX OF WEATHER
CONDITIONS FOR THIS UPCOMING WEEK. ISENTROPIC LIFT WILL MAINTAIN CHC
OF LIGHT RAIN THROUGH EARLY WEDNESDAY BEFORE DRIER AIR MOVES IN AND
A SLIGHT WARMING TREND COMMENCES. TEMPS ON TUE WILL STRUGGLE TO GET
OUT OF THE 40S DUE TO THICK CLOUD COVER...ALTHOUGH A FEW 50S ARE
POSSIBLE ALONG THE COAST AND OUT WEST. NEXT REINFORCING SURGE OF
HIGH PRESSURE ARRIVES EARLY WEDNESDAY WITH SCA CONDITIONS OCCURING
ON WED...HOWEVER...ABUNDANT SUNSHINE WILL ALLOW TEMPS TO REACH THE
60S BOTH WED-THU. NEXT FRONT ARRIVES LATE THURSDAY WITH A MODERATE
OFFSHORE FLOW DEVELOPING IN ITS WAKE. THE FRONT WILL DROP TEMPS BACK
INTO THE 40S-50S FOR FRIDAY BENEITH OVC SKIES. COULD BE A FEW
SHOWERS AS MOIST SOUTHERLY LOW LVL FLOW OVERRIDES THE COOL BOUNDARY
LAYER. THE COOL AIR WONT LAST LONG AS A DEEP TROUGH BEGINS TO TAKE
SHAPE ACROSS THE DESERT SW DRAWING A WARM FRONT BACK THROUGH THE
AREA SAT. TEMPS ON SAT WILL WARM BACK INTO THE LOW TO MID 60S SAT
WITH 70S EXPECTED SUNDAY.
&&
.PRELIMINARY POINT TEMPS/POPS...
CORPUS CHRISTI 47 48 38 50 43 / 50 70 40 20 30
VICTORIA 43 44 35 46 38 / 50 70 40 20 40
LAREDO 46 46 39 54 44 / 50 50 20 10 10
ALICE 45 46 37 50 41 / 50 70 40 20 30
ROCKPORT 47 50 39 50 43 / 50 70 40 30 40
COTULLA 42 43 35 50 40 / 50 50 30 10 10
KINGSVILLE 48 48 37 50 43 / 50 70 40 20 30
NAVY CORPUS 49 51 39 51 45 / 50 70 40 30 40
&&
.CRP WATCHES/WARNINGS/ADVISORIES...
TX...RIP CURRENT RISK UNTIL 6 PM CST THIS EVENING FOR THE FOLLOWING
ZONES: ARANSAS...CALHOUN...KLEBERG...NUECES.
GM...SMALL CRAFT ADVISORY FROM 10 PM THIS EVENING TO MIDNIGHT CST
MONDAY NIGHT FOR THE FOLLOWING ZONES: COASTAL WATERS FROM
BAFFIN BAY TO PORT ARANSAS OUT 20 NM...COASTAL WATERS FROM
PORT ARANSAS TO MATAGORDA SHIP CHANNEL OUT 20 NM...WATERS
FROM BAFFIN BAY TO PORT ARANSAS FROM 20 TO 60 NM...WATERS
FROM PORT ARANSAS TO MATAGORDA SHIP CHANNEL FROM 20 TO 60
NM.
SMALL CRAFT ADVISORY FROM 10 PM THIS EVENING TO 6 PM CST MONDAY
FOR THE FOLLOWING ZONES: BAYS AND WATERWAYS FROM BAFFIN BAY
TO PORT ARANSAS...BAYS AND WATERWAYS FROM PORT ARANSAS TO
PORT O`CONNOR.
&&
$$
PZ/83...AVIATION
AREA FORECAST DISCUSSION
NWS HOUSTON/GALVESTON TX
1106 AM CST SAT FEB 21 2015
.DISCUSSION...
SEE 18Z AVIATION DISCUSSION.
&&
.AVIATION...
FCST SOUNDINGS CONTINUE TO ADVERTISE MVFR CIGS WILL DEVELOP THIS
AFTN ALONG WITH SCT SHRA. SHRAS HAVE INCREASED IN COVERAGE OVER
THE LAST HOUR. IFR/LIFR CIGS EXPECTED TO DEVELOP OVERNIGHT AND
LINGER THROUGH MUCH OF SUNDAY MORNING. PW VALUES INCREASE RATHER
SIGNIFICANTLY AFTER 18Z SO ADDED VCSH TO THE IAH TAF FOR SUNDAY
AFTN. THERE IS ALSO SOME POTENTIAL FOR SEA FOG TO DEVELOP TONIGHT.
LATEST HRRR SHOWS SEA FOG DEVELOPING BETWEEN 00-03Z AND GRADUALLY
MOVING INLAND OVERNIGHT. 43
&&
.PREV DISCUSSION... /ISSUED 1039 AM CST SAT FEB 21 2015/
UPDATE...
SURFACE LOW OVER THE ARKLATEX WITH ITS ASSOCIATED TROUGH/COLD
FRONTAL BOUNDARY STRETCHING SOUTHWEST ACROSS AND PARALLEL TO THE
BALCONES ESCARPMENT. LIGHT AND WIDELY SCATTERED AREAS OF LIGHT
SHOWERS FORMING JUST DOWNSTREAM OF THE BOUNDARY AND MOVING NORTHEAST
(CAUGHT UP IN A WEAKENING LLJ) FROM ROUGHLY THE MATAGORDA BAY AREA
INTO THE PINEY WOODS. OVERCAST STRATUS AND COASTAL HAZE IN THIS
RELATIVELY MOIST ENVIRONMENT...SOUTHWEST TO SOUTH WINDS PULLING
IN MID-60 DEW POINT AIR FROM THE GULF. WEB CAMERAS ARE SHOWING
DENSE SEA FOG APPROACHING THE MATAGORDA BAY SHORELINE THIS
MORNING. PATCHY BECOMING AREAS OF SEA FOG WILL LIKELY AFFECT THE
LOCAL BAYS AND NEARSHORE WATERS THROUGH SUNDAY MORNING...OR UNTIL
THE FRONT MAKES ITS WAY OFF THE UPPER TEXAS COAST TOMORROW AFTERNOON.
SOUTHEAST TEXAS WILL REMAIN IN THE WARM SECTOR THROUGH EARLY EVENING.
THUS...TODAY`S FORECAST IS FOR LITTLE CHANGE IN THESE CURRENT CONDITIONS
OF OVERCAST WITH BRIEF PERIODS OF VERY LIGHT RAIN TO OCCANSIONAL DRIZZLE
/SPRINKLES...AFTERNOON TEMPERATURES BRIEFLY ACHIEVING THE LOWER TO
MIDDLE 70S. THE FRONTAL BOUNDARY IS TIMED TO REACH THE NORTHWESTERN
COUNTIES AROUND SUNSET TONIGHT...THE METRO AREA DURING THE PRE-DAWN
SUNDAY HOURS...AND THEN STALL OUT ALONG THE COASTAL COUNTIES THROUGH
SUNDAY AFTERNOON. A 1050-ISH MB LARGE HIGH DROPPING OUT OF CENTRAL
CANADA LATE TOMORROW WILL AID IN PUSHING THE FRONT OFF THE COAST
BY MIDNIGHT MONDAY. INCREASING NORTHEAST WINDS...WITH MID-LEVEL
SOUTH-SOUTHWEST WINDS...WILL ENHANCE ISENTROPIC LIFT THROUGH TUESDAY.
COLD AIR ADVECTION KICKING IN EARLY MONDAY MORNING WILL BE THE IMPETUS
TO AN OVERCAST AND COLD DAY IN THE 30S AND 40S. THIS OVERRUNNING
SCENARIO OF WARM MID-LEVEL DROPLETS FALLING THROUGH A VERY SHALLOW
SUB-FREEZING SURFACE LAYER WILL INCREASE THE PROBABILITY FOR THE
DEVELOPMENT OF FREEZING RAIN ACROSS THE NORTHERN THIRD OF THE CWA
FROM EARLY MONDAY EVENING THROUGH TUESDAY MORNING. 31
PREV DISCUSSION... /ISSUED 453 AM CST SAT FEB 21 2015/
DISCUSSION...
AREA RADAR SHOW SHOWERS STREAMING NORTH WITHIN A 40-50KT LLJ.
TEMPS ARE HOLDING STEADY IN THE MID 60S WITH DECENT WINDS MIXING
DOWN AND EVEN WIND GUSTS OF 30KTS AS OBSERVED AT KUTS AT 10Z. SFC
ANALYSIS HAS SFC LOW NEAR DFW METROPLEX WITH WARM FRONT EXTENDING
ENE FROM THE LOW TOWARDS THE ARKLATEX AND MID MISS RIVER VALLEY.
COLD FRONT IS DEVELOPING OVER N TX INTO THE TX PANHANDLE. WARM
SECTOR AIRMASS SUPPORTS DEWPOINTS IN THE LOW 60S WITH MID 60S IN
THE GULF. LLJ AXIS BENDS FROM THE UPPER TX COAST TOWARDS MISS
RIVER VALLEY HELPING TO FOCUS CONVECTION OVER N ARK INTO W TN.
UPPER LEVEL ANALYSIS AND WATER VAPOR IMAGERY SHOW THIS CONVECTION
HAVING SUPPORT FROM AN INITIAL SHORTWAVE AND A SECOND WAVE OVER
KS/OK. ANOTHER STRONGER WAVE REMAINS BACK OVER THE INTER-MTN WEST.
A CUTOFF LOW REMAINS OUT IN THE PACIFIC WHICH WILL HAVE A ROLE IN
RAIN CHANCES FOR EARLY NEXT WEEK.
SFC LOW OVER N TX THIS MORNING SHOULD QUICKLY MOVE EAST WITH COLD
FRONT PUSHING INTO TX. AHEAD OF THE FRONT THE WARM SECTOR WILL BE
MARGINALLY UNSTABLE WITH MAYBE 500-1000 J/KG OF CAPE. FORECAST
SOUNDINGS STILL SHOW A DECENT CAP FROM THE EML AROUND 800MB. GFS
IS SHOWING A STRONGER CAP THAN THE NAM WHICH WEAKENS THE CAP.
THINK BEST CHANCES FOR ANY STRONG/SEVERE STORMS WILL BE EAST OF
THE AREA INTO LA AND THAT IS STILL QUITE UNCERTAIN. FORECAST WILL
MAINTAIN A MENTION OF ISO TSRA BUT NOT VERY CONFIDENT. SHOWERS
UNDER THE CAP WILL BE MAIN PRECIP MODE. THE OTHER CONCERN FOR
TODAY WILL BE THE DEVELOPMENT OF SEA FOG FOR THE NEAR SHORE WATERS
OF THE UPPER TX COAST AND MATAGORDA/GALVESTON BAYS. WITH DEWPOINTS
INCREASING AND WATER TEMPS IN THE UPPER 50S...COULD GET FOG
FORMATION TONIGHT INTO SUN AS WINDS DECREASE.
TIMING THE FROPA CONTINUES TO BE A CHALLENGE. NAM/GFS BOTH HAVE
THE FRONT REACHING COLLEGE STATION TO CROCKETT AROUND 00-03Z SUN.
THE ECMWF LOOKS TO BE MAYBE 3 HRS BEHIND THAT WITH FROPA. THE
FRONT THEN SLOWS AND MAYBE REACHES HOUSTON METRO AROUND 09-12Z
SUN. THE NAM IS MORE PROGRESSIVE THAN THE GFS/ECMWF AT THIS POINT.
THE ECMWF DOES NOT REALLY PUSH THE FRONT OFF THE COAST UNTIL MAYBE
00-06Z MON. GFS SEEMS TO STALL THE FRONT ALONG I-10 DURING THE DAY
SUN AND THEN OFF THE COAST WITH SIMILAR TIMING. THE NAM ALSO
STALLS THE FRONT BUT MORE RIGHT ALONG THE COAST AND THEN PUSHES IT
COMPLETELY THROUGH SIMILAR TO THE GFS/ECMWF.
A LEAD SHORTWAVE TROUGH MOVES OVER THE AREA FROM THE UPPER LOW IN
THE PACIFIC SUN AFTERNOON. THIS INCREASES ISENTROPIC LIFT OVER THE
FRONT AND LEAD TO BETTER RAIN CHANCES. ANOTHER WEAK WAVE MOVES
OVER MONDAY BUT SEEMS THAT ISENTROPIC LIFT INCREASE MORE DUE TO
INCREASING JET OVER THE MAIN 850MB FRONT OVER N TX. RAIN CHANCES
GO FROM MAINLY 40 POPS ON SUNDAY TO 50 PERCENT ON MONDAY. PRECIP
LOOKS TO CONTINUE FALLING MON NIGHT INTO TUE. THIS ALSO
CORRESPONDS TO WHEN THE COLDEST AIR WILL BE OVER SE TX. TEMPS
SHOULD NOT INCREASE MUCH MONDAY AND IN FACT COULD SLOWLY DROP
DURING THE DAY. TEMP PROFILES AT CLL AND LFK ON GFS BUFR SOUNDINGS
SHOW A SUB FREEZING LAYER MAYBE 1500-2000FT THICK DEVELOP NEAR THE
SFC WITH A STRONG WARM NOSE AT 850MB 00Z TUE THROUGH 15Z TUE. SUB
FREEZING LAYER IS THICKER AT LFK. DURING THE SAME TIME THE NAM IS
NOT AS COLD AS THE GFS BUT PROFILES STILL SUPPORT FREEZING RAIN AT
CLL THROUGH LFK. THERE DOES NOT SEEM TO BE ENOUGH SEEDING ALOFT TO
SUGGEST SLEET PLUS THE WARM NOSE IS TOO STRONG AND LIKELY MELT ANY
SLEET/SNOW FALLING THROUGH THE COLUMN. PRECIP AMOUNTS FROM 00Z TO
15Z TUE MAY PUSH AT MOST A TENTH OF AN INCH WHICH WILL BE CLOSE TO
ICE ACCUMULATION CRITERIA OF A WINTER STORM WARNING. THE MAIN
ISSUE WITH THE COLDER GFS IS THAT RAIN WILL LIKELY BE FALLING
DURING THIS TIME WHICH COULD ACT TO WARM THE PROFILE SINCE THERE
WILL BE NO EVAPORATION. THIS MEANS TEMPS COULD POTENTIALLY REMAIN
ABOVE FREEZING. THAT SAID COLD ADVECTION IN SHALLOW COLD AIRMASS
LIKE THIS IS DIFFICULT TO DETERMINE.
SHOULD FREEZING RAIN DEVELOP MON NIGHT INTO TUE...IT STILL LOOKS
LIKE THE MAIN AREAS IMPACTED WILL BE FROM CALDWELL TO COLLEGE
STATION TO HUNTSVILLE AND LIVINGSTON NORTHWARD. AREAS FROM
MADISONVILLE TO CROCKETT OVER TO LUFKIN WILL LIKELY HAVE THE BEST
CHANCES OF FREEZING RAIN AND ICE ACCUMULATIONS. THIS MATCHES WELL
WITH WPC THINKING IN THEIR FREEZING RAIN PROBABILITIES. AT THIS
TIME ICE ACCUMULATION SHOULD BE LESS THAN A TENTH OF AN INCH BUT
THAT COULD CHANGE. NOTE THAT AREAS SOUTH OF BRENHAM TO CLEVELAND
LINE SHOULD REMAIN WARM ENOUGH FOR PRECIP TO BE RAIN. NO IMPACTS
ARE EXPECTED FOR THE HOUSTON METRO AREA AT THIS TIME.
TROUGHING CURRENTLY OVER THE INTER-MTN WEST DOES DEVELOP INTO A
CLOSED LOW OVER THE GREAT BASIN BY SUN NIGHT INTO MON. THIS LOW
THEN BEGINS TO MOVE ACROSS THE S ROCKIES IN RESPONSE TO ANOTHER
UPPER LOW MOVING INTO THE GREAT LAKES ON TUE. THE ECMWF AND GFS
ARE IN PRETTY GOOD AGREEMENT WITH THE SYSTEM MOVING OVER TX WITH A
POS TILT ON WED. THIS SHOULD PROVIDE THE EASTERN HALF OF THE AREA
WITH HIGHER RAIN CHANCES WHICH MOVE EAST QUICKLY. THE TROUGH DOES
BECOME MORE NEG TILT WED NIGHT INTO THUR IMPACTING THE SE U.S. AS
THE SYSTEM MOVES EAST ANOTHER COLD FRONT BEGINS TO MOVE SOUTH INTO
TX. THIS FRONT SHOULD REACH THE AREA THUR/FRI OF THE COMING WEEK
WITH ANOTHER TROUGH FORMING OVER THE S ROCKIES. THIS MAY SET THE
STAGE FOR ANOTHER OVERRUNNING PRECIP EVENT NEXT WEEKEND.
39
MARINE...
STRONG ONSHORE FLOW AND ELEVATED SEAS CONTINUE ACROSS THE COASTAL
WATERS THIS MORNING. WINDS WILL BEGIN TO EASE LATE TODAY WITH SEAS
LOWERING OVERNIGHT. HAVE EXTENDED THE CURRENT SMALL CRAFT ADVISORY
FOR ALL COASTAL WATERS THROUGH MIDNIGHT TONIGHT. SEA FOG
DEVELOPMENT IS POSSIBLE OVERNIGHT INTO SUNDAY MORNING. AFTER A
BRIEF RESPITE A STRONG COLD FRONT WILL MOVE OFFSHORE ON SUNDAY
BRINGING INCREASED NORTHEAST WINDS AND BUILDING SEAS. ELEVATED
WINDS AND SEAS WILL PERSIST THROUGH AT LEAST TUESDAY IN THE WAKE
OF THE FRONT WITH ADVISORY AND CAUTION FLAGS LIKELY. 38
&&
.PRELIMINARY POINT TEMPS/POPS...
COLLEGE STATION (CLL) 74 51 57 37 38 / 30 20 50 40 50
HOUSTON (IAH) 75 58 65 39 42 / 30 30 40 40 50
GALVESTON (GLS) 69 60 66 44 46 / 20 20 30 40 50
&&
.HGX WATCHES/WARNINGS/ADVISORIES...
TX...NONE.
GM...SMALL CRAFT SHOULD EXERCISE CAUTION UNTIL 6 PM CST THIS EVENING
FOR THE FOLLOWING ZONES: GALVESTON BAY...MATAGORDA BAY.
SMALL CRAFT ADVISORY UNTIL MIDNIGHT CST TONIGHT FOR THE
FOLLOWING ZONES: WATERS FROM FREEPORT TO THE MATAGORDA SHIP
CHANNEL 20 NM TO 60 NM...WATERS FROM FREEPORT TO THE
MATAGORDA SHIP CHANNEL OUT 20 NM...WATERS FROM HIGH ISLAND
TO FREEPORT 20 TO 60 NM...WATERS FROM HIGH ISLAND TO
FREEPORT OUT 20 NM.
&&
$$
DISCUSSION...31
AVIATION/MARINE...43
AREA FORECAST DISCUSSION
NWS GREEN BAY WI
529 PM CST SUN FEB 22 2015
UPDATED AVIATION PORTION FOR 00Z TAF ISSUANCE
.SHORT TERM...TONIGHT AND MONDAY
ISSUED AT 231 PM CST SUN FEB 22 2015
THE LATEST RAP ANALYSIS AND SATELLITE/RADAR IMAGERY SHOW ARCTIC HIGH
PRESSURE DRIFTING SOUTHEAST OVER THE NORTHERN GREAT PLAINS EARLY
THIS AFTERNOON. THOUGH COLD ADVECTION IS ONGOING...HEATING HAS
SERVED TO STEEPEN LOW LEVEL LAPSE RATES...WHICH TRIGGERED A CU FIELD
TO FORM LATE IN THE MORNING. DRY AIR IS WINNING OUT THIS AFTERNOON
AS EVIDENT BY THE CU FIELD DIMINISHING. ONLY CLEAR AND BITTERLY
COLD CONDITIONS EXIST UPSTREAM...SO FORECAST CONCERNS INCLUDE TEMPS
AND WIND CHILLS THROUGH MONDAY.
TONIGHT...STRONG ARCTIC HIGH PRESSURE WILL BE SLIDING SOUTHEAST FROM
THE NORTHERN GREAT PLAINS TO CENTRAL IOWA. LOSS OF DIURNAL HEATING
WILL CAUSE ANY LINGERING CU TO DISSIPATE BY EARLY THIS
EVENING...WHICH WILL LEAVE CLEAR SKIES FOR MUCH OF THE NIGHT.
BECAUSE THE ARCTIC HIGH WILL DROP SOUTHWEST OF THE REGION...BOTH
STATISTICAL AND NUMERICAL GUIDANCE POINT TOWARDS WINDS REMAINING IN
THE 5 TO 10 KT RANGE THIS EVENING...BEFORE DIMINISHING SOME
OVERNIGHT. SOME POTENTIAL FOR DECOUPLING OVER N-C WISCONSIN AS
BOUNDARY LAYER WINDS LIGHTEN. AS A RESULT...THINK TEMPERATURES HAVE
A CHANCE TO TUMBLE LATE TONIGHT. THIS MAKES FOR A DILEMMA IN TERMS
OF HEADLINE DECISIONS. IF WINDS REMAIN IN THE 4-5 KT RANGE...SOME
PLACES LIKE ANTIGO AND RHINELANDER COULD REACH WIND CHILL WARNING
CRITERIA FOR A PERIOD LATE TONIGHT INTO MONDAY MORNING. THINK
WARNING CONDITIONS WILL NOT BE WIDESPREAD ENOUGH DUE TO WINDS
DROPPING OFF. SO WILL STICK WITH THE ADVISORY THROUGH THE NIGHT AND
CONTINUE TO MENTION THAT SOME SPOTS WILL HIT WARNING CRITERIA. IF
WINDS DO DROP OFF...TEMPS 25 TO 30 BELOW ARE POSSIBLE.
MONDAY...HIGH PRESSURE WILL BE DRIFTING TO THE MID-MISSISSIPPI
VALLEY WHILE THE NEXT CLIPPER WILL REACH NORTHERN MINNESOTA LATE IN
THE AFTERNOON. A TIGHTENING PRESSURE GRADIENT BETWEEN THESE
FEATURES WILL CAUSE WINDS TO SWING AROUND TO THE SOUTHWEST AND
BECOME GUSTY IN THE AFTERNOON. BUT THE SOUTHWEST WINDS WILL ALSO
HELP MODERATE THE BITTERLY COLD AIRMASS. WIND CHILLS WILL BE
WARMING ABOVE ADVISORY CRITERIA BY LATE IN THE MORNING SO THE ENDING
TIME LOOKS ABOUT RIGHT. THOUGH CIRRUS WILL BE INCREASING IN THE
AFTERNOON...HIGHS WILL WARM INTO THE UPPER SINGLE DIGITS TO THE
LOWER TEENS.
.LONG TERM...MONDAY NIGHT THROUGH SUNDAY
ISSUED AT 231 PM CST SUN FEB 22 2015
OVERALL UPPER LEVEL PATTERN CONSISTING OF A WESTERN RIDGE AND
EASTERN TROUGH WILL REMAIN FOR MOST OF THE PERIOD...ALTHOUGH THERE
ARE HINTS THAT THE WESTERN RIDGE MAY REORGANIZE FURTHER WEST OVER
THE PACIFIC WHILE FLOW OVER THE UNITED STATES TAKES ON MORE OF AN
APPEARANCE OF SPLIT FLOW. THIS CHANGE DOES NOT LOOK LIKE IT WILL
DO MUCH TO REVERSE OUR TREND OF SEEING TEMPS WELL BELOW
NORMAL. FOR NOW...ONLY TUESDAY LOOKS TO SEE HIGHS RELATIVELY NEAR
NORMAL...WITH A RETURN TO COLD WEATHER AFTER A FRONT MOVES
THROUGH.
THE PRIMARY CHANCE FOR MEASURABLE SNOW LOOKS TO BE MONDAY NIGHT
AND TUESDAY AS A LOW PRESSURE PASSES NORTH THROUGH ONTARIO...WITH
AN ATTACHED COLD FRONT PUSHING ACROSS THE AREA ONCE AGAIN. GUIDANCE
CONTINUES TO LIKE OUR FAR NORTH FOR THE BEST CHANCE AND AMOUNTS OF
SNOW...TO BE EXPECTED AS THE LOW PASSES SOME DISTANCE TO OUR NORTH
AND EAST. HOWEVER...THE GFS AND TO SOME EXTENT THE GEM PROVIDE
BETTER MOISTURE AND LIFT...AND BRING AN INCH OR TWO OF SNOW DOWN
THROUGH A LARGE PORTION OF THE NORTHEAST QUARTER OF WISCONSIN. IT
IS WORTH NOTING THAT THE GFS ENSEMBLE CONTINUES TO NOT BE AS
ENAMORED OF THIS IDEA AS THE DETERMINISTIC RUN. IN GENERAL WILL
FOLLOW SUIT...PUTTING THE HIGHEST POPS AND ACCUMULATIONS IN FAR
NORTHERN WISCONSIN...BUT WILL PAY SOME DEFERENCE TO THE NORTH
AMERICAN MODELS AND THEIR PLAUSIBLE...IF NOT AS CONVINCING...IDEA
OF MORE SNOW FURTHER TO THE SOUTH AND WEST WITH CHANCE POPS
TUESDAY MORNING.
ALONG WITH THIS SNOW...OUR POSITION BETWEEN THIS ONCOMING
LOW AND THE HIGH RESPONSIBLE FOR OUR MOST RECENT COLD PLUNGE WILL
RESULT IN GUSTY SOUTHWEST WINDS MONDAY NIGHT INTO TUESDAY. THIS
COULD CREATE SOME BLOWING AND DRIFTING OF ANY SNOW THAT MAY
FALL...EVEN IF AMOUNTS ARE NOT PARTICULARLY HIGH. GUIDANCE IS
UNANIMOUS IN STRONG 50 TO 65 KNOT WINDS AT RELATIVELY LOW ALTITUDE
VERY EARLY TUESDAY MORNING. SOUNDINGS IN BUFKIT SHOW POTENTIAL
GUSTS TO 20-30 KTS...AND GUSTS EVEN A LITTLE HIGHER ARE NOT OUT OF
THE QUESTION...THOUGH THIS SCENARIO WOULD NEED BETTER MIXING TO
COME TO FRUITION.
AFTERWARDS...HIGH PRESSURE SETTLES OVER THE AREA BRINGING DRY
WEATHER THROUGH SATURDAY. IN WHAT SURELY IS BEGINNING TO SOUND ALL
TOO FAMILIAR...WE WILL SEE ANOTHER SHOT OF WELL BELOW NORMAL
TEMPERATURES. THE COLDEST PERIOD LOOKS TO BE TUESDAY NIGHT THROUGH
THURSDAY. HIGHS ON WEDNESDAY LOOK TO BE MIRED IN THE SINGLE DIGITS
FOR MOST...WITH SUBZERO LOWS ON TAP TUESDAY AND WEDNESDAY NIGHT.
A SLOW MODERATION IN TEMPERATURES IS EXPECTED THROUGH THE WEEKEND.
ANOTHER CHANCE FOR PRECIPITATION EMERGES DURING THE WEEKEND...BUT
WITH A GOOD BIT OF UNCERTAINTY IN THE NATURE OF THE UPPER
FLOW...WILL NOT SPECULATE ON THE DETAILS FOR NOW.
&&
.AVIATION...FOR 00Z TAF ISSUANCE
ISSUED AT 527 PM CST SUN FEB 22 2015
VFR CONDITIONS TO PREVAIL TNGT THRU MON AS A LARGE AREA OF HI PRES
MOVES FROM THE NRN PLAINS SE TOWARD THE OHIO RIVER VALLEY. WINDS
ARE FCST TO SLOWLY BACK FROM NW THIS EVENING...TO WEST MON MORNING...
TO SW MON AFTERNOON. THE PRES GRADIENT WL GRADUALLY TIGHTEN BY MON
AFTERNOON BETWEEN THE HI PRES TO OUR SOUTH AND AN AREA OF LOW PRES
RESIDING WELL TO OUR NORTH. WIND GUSTS COULD APPROACH 20 KTS BY
LATE MON. NE WI WL ALSO SEE AN INCREASE IN MID/HI CLOUDS ON MON
AHEAD OF A CDFNT THAT IS FCST TO MOVE THRU THE AREA ON TUE.
&&
.GRB WATCHES/WARNINGS/ADVISORIES...
WIND CHILL ADVISORY FROM 9 PM THIS EVENING TO 10 AM CST MONDAY
FOR WIZ013-020>022-031-037>040-045-048>050-073-074.
WIND CHILL ADVISORY UNTIL 10 AM CST MONDAY FOR WIZ005-010>012-
018-019-030-035-036.
&&
$$
SHORT TERM.....MPC
LONG TERM......LUCHS
AVIATION.......AK
FORECAST DISCUSSION FOR ROUTINE AFTERNOON FORECAST ISSUANCE
.SHORT TERM...TONIGHT AND SUNDAY
ISSUED AT 224 PM CST SAT FEB 21 2015
THE LATEST RAP ANALYSIS AND SATELLITE/RADAR IMAGERY SHOW THE NEXT
ARCTIC COLD FRONT DROPPING SOUTHEAST ACROSS NORTH-CENTRAL TO
WEST-CENTRAL WISCONSIN EARLY THIS AFTERNOON. LIGHT AREA OF SNOW
RESIDING WITHIN A WEAK MID-LEVEL FGEN ZONE IS MOVING EAST ACROSS
CENTRAL WISCONSIN...THOUGH SUSPECT SOME OF THAT AREA IS NOT REACHING
THE GROUND. ADDITIONALLY...ALSO SEEING LIGHT RETURNS DEVELOPING
OVER OCONTO AND MARINETTE COUNTIES WHERE WEAK SURFACE CONVERGENCE
HAS DEVELOPED. THIS WILL LIKELY EXPAND LATER THIS AFTERNOON BASED ON
TRENDS AND ACCORDING TO THE HI-RES MODELS. BEHIND THE
FRONT...ARCTIC HIGH PRESSURE IS BUILDING SOUTHEAST INTO THE NORTHERN
PLAINS WHERE TEMPS WERE WELL BELOW ZERO EARLIER THIS MORNING.
FORECAST CONCERNS INCLUDE LIGHT SNOW CHANCES THROUGH THIS
EVENING...BEFORE ATTENTION TURNS TO DANGEROUS WIND CHILLS.
TONIGHT...A SHORTWAVE TROUGH OVER SOUTH-CENTRAL CANADA WILL DRIVE
THE COLD FRONT ACROSS THE REST OF THE REGION THIS EVENING...WHILE A
BEEFY ARCTIC HIGH MOVES INTO THE NORTHERN GREAT PLAINS AND WESTERN
GREAT LAKES. AHEAD OF THE SHORTWAVE...THE HIGHER RES MODELS ARE
DEPICTING A WEAK SURFACE TROUGH DEVELOPING OVER NORTHEAST WISCONSIN
THIS EVENING WHICH COULD PROMOTE LIGHT SNOW DEVELOPMENT. HAVE KEPT
A SMALL CHANCE IN THE FORECAST THROUGH THE EVENING TO ACCOUNT FOR
THIS FEATURE. OTHERWISE...THE INCOMING ARCTIC HIGH WILL PUSH
RESIDUAL MID-LEVEL MOISTURE TO THE EAST WHICH WILL END SNOW CHANCES
BY AROUND MIDNIGHT. TEMPERATURES SHOULD FALL QUICKLY AS SKIES CLEAR
AND ARCTIC AIR POURS ACROSS THE REGION. POTENTIAL IS THERE FOR
DECOUPLING OVER N-C WISCONSIN...BUT THINKING IF WINDS BECOME CALM IT
WILL BE ONLY FOR A BRIEF TIME. THE COMBINATION OF COLD TEMPS AND
THE BRISK NW WINDS SUPPORT THE WIND CHILL ADVISORY CURRENTLY IN
EFFECT SO NO CHANGES TO HEADLINES.
SUNDAY...COLD ADVECTION WILL CONTINUE INTO SUNDAY MORNING AND TEMPS
COULD CONTINUE THEIR FALL INTO MID-MORNING DESPITE AMPLE SUNSHINE.
THE PRESSURE GRADIENT WILL SLACKEN A BIT THROUGH THE DAY AS THE
CENTER OF THE HIGH DRIFTS CLOSER TO THE REGION...BUT PROJECTED WIND
CHILLS WILL ONLY WARM TO AROUND 15 TO 22 BELOW THROUGH THE
AFTERNOON. THIS IS CLOSE ENOUGH TO LEAVE THE ENDING TIME OF THE
ADVISORY ALONE. HIGHS WILL ONLY WARM INTO THE -5 TO 0 RANGE NORTH
TO THE 5 TO 10 ABOVE RANGE SOUTH.
.LONG TERM...SUNDAY NIGHT THROUGH SATURDAY
ISSUED AT 224 PM CST SAT FEB 21 2015
A LOOK AT THE RECENT BEHAVIOR OF THE 500 MB PATTERN FITS IN WELL
WITH OUR TEMPERATURES THIS MONTH. A WESTERN RIDGE AND EASTERN
TROUGH ARE QUITE PERSISTENT...SHOWING CHANGES MORE IN AMPLITUDE
THAN POSITION. WITH THAT...OUR TEMPERATURES HAVE SPENT TIME
VARYING BETWEEN BELOW NORMAL AND WAY BELOW NORMAL. FOR THE TIME
BEING...THIS TREND LOOKS TO CONTINUE.
SUNDAY NIGHT INTO MONDAY MORNING SHOWS TEMPERATURES BOTTOMING OUT
NEARLY AS LOW AS THEY HAVE GOTTEN THIS WINTER. FORECASTING WIND
CHILLS WILL BE DIFFICULT ACROSS THE NORTH. CALM WINDS WILL HELP
TEMPERATURES FALL TO THEIR COLDEST POSSIBLE LEVELS...BUT CALM
CONDITIONS COULD PRECLUDE A WARNING BY NOT MEETING THE WIND
THRESHOLD. MORE WIND WILL HELP PUSH WIND CHILLS DOWN...BUT WOULD
BE LIMITING BY ARRESTING TEMPERATURE FALLS. GIVEN THE
UNCERTAINTY...WILL LET LATER SHIFTS MAKE THE FINAL DECISION ON
ANYTHING TO BE ISSUED FOR WIND CHILL. AN ADVISORY FOR MOST OR ALL
OF THE AREA IS PLAUSIBLE...AND A WARNING IN NORTH CENTRAL
WISCONSIN MAY BE ON THE TABLE. THOUGH THERE MIGHT BE A LACK OF
CONFIDENCE IN THE PRECISE HEADLINES...CONFIDENCE IS QUITE HIGH
THAT IT WILL BE VERY COLD AND THOSE GOING TO WORK AND SCHOOL
MONDAY MORNING SHOULD PREPARE ACCORDINGLY.
INCREASING SOUTHWEST WINDS ON MONDAY CAN BE EXPECTED...ESPECIALLY
LATE IN THE AFTERNOON AND EVENING HOURS. THESE WINDS WILL HELP
BOOST TEMPERATURES LATE MONDAY INTO TUESDAY. WITH ANOTHER IN THE
PARADE OF LOWS SLIDING BY TO OUR NORTHEAST BRINGING AN ARCTIC
FRONT TO OUR AREA...WE WILL HAVE ANOTHER CHANCE FOR SNOW SHOWERS.
GUIDANCE REMAINS FRUSTRATINGLY ON THE EDGE BETWEEN BRINGING SOME
LIGHT SNOW WELL INTO THE AREA...OR ONLY BRINGING A GLANCING BLOW
TO THE NORTH AND EAST. ULTIMATELY THIS FORECAST DOES NOT MAKE
SIGNIFICANT CHANGES...THE EQUIVALENT OF DUMPING THE PUCK INTO THE
CORNER AND HOPING THAT A LINE CHANGE OF MODELS WILL BRING MORE
CLARITY.
BITTER COLD RETURNS FOR WEDNESDAY AND THURSDAY BUT WITH SOME HOPE FOR
A SLIGHT BUMP UP TO MERELY BELOW NORMAL TEMPERATURES LATE IN THE WEEK.
&&
.AVIATION...FOR 18Z TAF ISSUANCE
ISSUED AT 1136 AM CST SAT FEB 21 2015
AN AREA OF LIGHT SNOW AND FLURRIES IS EXPECTED TO MOVE
OVER THE CENTRAL WISCONSIN AND FOX VALLEY TAF SITES THIS AFTERNOON.
INCLUDED MVFR VSBYS AT AUW AND CWA BUT NOT FURTHER EAST TO GET A
BETTER HANDLE ON TIMING/CONDITIONS. ANY LIGHT SNOW WILL EXIT THE
REGION DURING THE EVENING...AND AN INCOMING ARCTIC AIRMASS WILL
PROMOTE CLEARING SKIES FOR THE REST OF THE NIGHT. VFR CONDITIONS
WILL THEN CONTINUE THROUGH THE END OF THE TAF PERIOD.
NOTICE TO AIRPORT GROUNDS CREW AND MAINTENANCE...THERE COULD BE A
SIGNIFICANT PERIOD OF BLOWING AND DRIFTING SNOW MONDAY EVENING
THROUGH TUESDAY MORNING. SOUTHWEST WINDS WILL INCREASE TO 15 TO 25
KNOTS WITH GUSTS TO 35 KNOTS POSSIBLE. THIS COULD PRODUCE
SIGNIFICANT BLOWING AND DRIFTING SNOW.
&&
.GRB WATCHES/WARNINGS/ADVISORIES...
WIND CHILL ADVISORY FROM 3 AM TO 11 AM CST SUNDAY FOR WIZ005-
010>012-018-019-030-035-036.
&&
$$
SHORT TERM.....MPC
LONG TERM......LUCHS
AVIATION.......MPC
AREA FORECAST DISCUSSION
NWS GREEN BAY WI
1136 AM CST SAT FEB 21 2015
UPDATED AVIATION PORTION FOR 18Z TAF ISSUANCE
.SHORT TERM...TODAY...TONIGHT...AND SUNDAY
ISSUED AT 408 AM CST SAT FEB 21 2015
SLOW MOVING ARCTIC FRONT WILL MOVE ACROSS THE AREA THIS MORNING
THEN STALL JUST TO OUR SOUTH AS A WAVE MOVES NORTHEAST ALONG THE
FRONT. THE NAM AND RUC SUGGEST THAT THERE WILL BE SOME LOW LEVEL
CONVERGENCE OVER THE FOX VALLEY AND HAVE FIVE TO TEN HUNDREDTHS OF
AN INCH OF WATER EQUIVALENT. THESE MODELS USUALLY PRETTY GOOD WITH
SMALL SCALE FEATURES SO WENT ALONG WITH THIS IDEA FOR THE MOST
PART. SNOW SHOWERS OR FLURRIES LIKELY ELSEWHERE THIS AFTERNOON.
THIS WILL BE ONE OF THE WARMEST DAYS IN A WEEK OR SO WITH HIGHS IN
THE 20S.
WHATEVER SNOW IS LEFTOVER THIS EVENING SHOULD END BY MIDNIGHT AS
THE FRONT ACCELERATES TO THE SOUTH AND ARCTIC AIR POURS INTO
WISCONSIN. LOWS TONIGHT SHOULD GET BELOW ZERO OVER ALL BUT EAST
CENTRAL WISCONSIN. WINDS SHOULD BE SUFFICIENT TO PRODUCE WIND
CHILLS OF 20 TO 30 BELOW ZERO IN CENTRAL AND NORTHCENTRAL
WISCONSIN WHERE ADVISORIES HAVE BEEN ISSUED. TEMPERATURES SHOULD
BE AROUND 15 DEGREES BELOW NORMAL.
SUNDAY SHOULD BE BLUSTERY AND COLD WITH HIGHS IN THE SINGLE
NUMBERS. SOME PLACES IN THE NORTH COULD STAY JUST BELOW ZERO.
WINDS CHILLS WILL BE 10 TO 20 BELOW ZERO OR COLDER.
.LONG TERM...SUNDAY NIGHT THROUGH FRIDAY
ISSUED AT 408 AM CST SAT FEB 21 2015
WESTERN 500MB RIDGE WILL KEEP REINVENTING ITSELF THROUGH 240 HOURS...
LEADING TO BELOW NORMAL TEMPERATURES ACROSS OUR NECK OF THE WOODS.
THE GOOD NEWS IS THE CALENDAR WILL TURN TO MARCH BY THE END OF
THE FORECAST PERIOD...THUS YOU WOULD THINK TEMPERATURES WOULD
FINALLY RETURN A LITTLE BIT CLOSER TO NORMAL. LAST CHECK OF THE
CLIMATE DATA AT GREEN BAY...WAUSAU AND RHINELANDER INDICATED
TEMPERATURES WERE RUNNING 8 TO 11 DEGREES BELOW NORMAL FOR THE
MONTH. VERY IMPRESSIVE AND POSSIBLY COULD NOT GET ANY WORSE!
THE ROLLER COASTER RIDE WILL BE BOTTOMING OUT SUNDAY NIGHT INTO
MONDAY MORNING. WIND CHILL READINGS HARD TO GAUGE ACROSS THE NORTH
DUE TO THE RIDGE SOUTH OF OUR AREA. SHOULD BE A LIGHT WIND AROUND...
BUT OUR TYPICAL COLD SPOTS LIKE MERRILL...TOMAHAWK AND LAND O LAKES
WILL PROBABLY GO CALM FOR AWHILE AND WOULD NOT MEET THE TRUE WIND
REQUIREMENTS FOR A WIND CHILL ADVISORY OR WARNING. WILL LET LATER
SHIFTS DECIDE IF WIND CHILL WARNING OR ADVISORY WOULD BE NEEDED
FOR THIS AREA...WHILE THE REST OF NORTHEAST AND EAST-CENTRAL
WISCONSIN WILL NEED A WIND CHILL ADVISORY.
INCREASING SOUTHWEST WINDS ON MONDAY CAN BE EXPECTED...ESPECIALLY
LATE IN THE AFTERNOON AND EVENING HOURS. WITH SUCH A FLUFFY SNOW
FROM YESTERDAY...COULD BE SOME BLOWING AND DRIFTING OF THE SNOW.
ENJOY THE HEAT ON TUESDAY AS NEXT CLIPPER SYSTEM DROPS INTO THE
AREA. WILL HAVE CHANCES FOR SNOW SHOWERS WITH THIS FEATURE AND
ALONG THE ARCTIC FRONT. NEW ECMWF MORE BULLISH ON TEMPERATURES
WITH TEMPERATURES POSSIBLE REACH THE LOWER TO MIDDLE 30S. DID NOT
STRAY TOO FAR FROM PREVIOUS FORECAST FOR NOW SINCE THERE HAS BEEN
SOME DIFFERENCES IN HOW MUCH WARM AIR WILL MAKE IT INTO THE AREA
AHEAD OF THE ARCTIC FRONT.
BITTER COLD RETURNS FOR WEDNESDAY AND THURSDAY WITH SOME MODIFICATION
IN TEMPERATURES NEXT FRIDAY.
&&
.AVIATION...FOR 18Z TAF ISSUANCE
ISSUED AT 1136 AM CST SAT FEB 21 2015
AN AREA OF LIGHT SNOW AND FLURRIES IS EXPECTED TO MOVE
OVER THE CENTRAL WISCONSIN AND FOX VALLEY TAF SITES THIS AFTERNOON.
INCLUDED MVFR VSBYS AT AUW AND CWA BUT NOT FURTHER EAST TO GET A
BETTER HANDLE ON TIMING/CONDITIONS. ANY LIGHT SNOW WILL EXIT THE
REGION DURING THE EVENING...AND AN INCOMING ARCTIC AIRMASS WILL
PROMOTE CLEARING SKIES FOR THE REST OF THE NIGHT. VFR CONDITIONS
WILL THEN CONTINUE THROUGH THE END OF THE TAF PERIOD.
NOTICE TO AIRPORT GROUNDS CREW AND MAINTENANCE...THERE COULD BE A
SIGNIFICANT PERIOD OF BLOWING AND DRIFTING SNOW MONDAY EVENING
THROUGH TUESDAY MORNING. SOUTHWEST WINDS WILL INCREASE TO 15 TO 25
KNOTS WITH GUSTS TO 35 KNOTS POSSIBLE. THIS COULD PRODUCE
SIGNIFICANT BLOWING AND DRIFTING SNOW.
&&
.GRB WATCHES/WARNINGS/ADVISORIES...
WIND CHILL ADVISORY FROM 3 AM TO 11 AM CST SUNDAY FOR WIZ005-
010>012-018-019-030-035-036.
&&
$$
SHORT TERM.....RDM
LONG TERM......ECKBERG
AVIATION.......MPC
AREA FORECAST DISCUSSION
NWS GREEN BAY WI
543 AM CST SAT FEB 21 2015
UPDATED AVIATION PORTION FOR 12Z TAF ISSUANCE
.SHORT TERM...TODAY...TONIGHT...AND SUNDAY
ISSUED AT 408 AM CST SAT FEB 21 2015
SLOW MOVING ARCTIC FRONT WILL MOVE ACROSS THE AREA THIS MORNING
THEN STALL JUST TO OUR SOUTH AS A WAVE MOVES NORTHEAST ALONG THE
FRONT. THE NAM AND RUC SUGGEST THAT THERE WILL BE SOME LOW LEVEL
CONVERGENCE OVER THE FOX VALLEY AND HAVE FIVE TO TEN HUNDREDTHS OF
AN INCH OF WATER EQUIVALENT. THESE MODELS USUALLY PRETTY GOOD WITH
SMALL SCALE FEATURES SO WENT ALONG WITH THIS IDEA FOR THE MOST
PART. SNOW SHOWERS OR FLURRIES LIKELY ELSEWHERE THIS AFTERNOON.
THIS WILL BE ONE OF THE WARMEST DAYS IN A WEEK OR SO WITH HIGHS IN
THE 20S.
WHATEVER SNOW IS LEFTOVER THIS EVENING SHOULD END BY MIDNIGHT AS
THE FRONT ACCELERATES TO THE SOUTH AND ARCTIC AIR POURS INTO
WISCONSIN. LOWS TONIGHT SHOULD GET BELOW ZERO OVER ALL BUT EAST
CENTRAL WISCONSIN. WINDS SHOULD BE SUFFICIENT TO PRODUCE WIND
CHILLS OF 20 TO 30 BELOW ZERO IN CENTRAL AND NORTHCENTRAL
WISCONSIN WHERE ADVISORIES HAVE BEEN ISSUED. TEMPERATURES SHOULD
BE AROUND 15 DEGREES BELOW NORMAL.
SUNDAY SHOULD BE BLUSTERY AND COLD WITH HIGHS IN THE SINGLE
NUMBERS. SOME PLACES IN THE NORTH COULD STAY JUST BELOW ZERO.
WINDS CHILLS WILL BE 10 TO 20 BELOW ZERO OR COLDER.
.LONG TERM...SUNDAY NIGHT THROUGH FRIDAY
ISSUED AT 408 AM CST SAT FEB 21 2015
WESTERN 500MB RIDGE WILL KEEP REINVENTING ITSELF THROUGH 240 HOURS...
LEADING TO BELOW NORMAL TEMPERATURES ACROSS OUR NECK OF THE WOODS.
THE GOOD NEWS IS THE CALENDAR WILL TURN TO MARCH BY THE END OF
THE FORECAST PERIOD...THUS YOU WOULD THINK TEMPERATURES WOULD
FINALLY RETURN A LITTLE BIT CLOSER TO NORMAL. LAST CHECK OF THE
CLIMATE DATA AT GREEN BAY...WAUSAU AND RHINELANDER INDICATED
TEMPERATURES WERE RUNNING 8 TO 11 DEGREES BELOW NORMAL FOR THE
MONTH. VERY IMPRESSIVE AND POSSIBLY COULD NOT GET ANY WORSE!
THE ROLLER COASTER RIDE WILL BE BOTTOMING OUT SUNDAY NIGHT INTO
MONDAY MORNING. WIND CHILL READINGS HARD TO GAUGE ACROSS THE NORTH
DUE TO THE RIDGE SOUTH OF OUR AREA. SHOULD BE A LIGHT WIND AROUND...
BUT OUR TYPICAL COLD SPOTS LIKE MERRILL...TOMAHAWK AND LAND O LAKES
WILL PROBABLY GO CALM FOR AWHILE AND WOULD NOT MEET THE TRUE WIND
REQUIREMENTS FOR A WIND CHILL ADVISORY OR WARNING. WILL LET LATER
SHIFTS DECIDE IF WIND CHILL WARNING OR ADVISORY WOULD BE NEEDED
FOR THIS AREA...WHILE THE REST OF NORTHEAST AND EAST-CENTRAL
WISCONSIN WILL NEED A WIND CHILL ADVISORY.
INCREASING SOUTHWEST WINDS ON MONDAY CAN BE EXPECTED...ESPECIALLY
LATE IN THE AFTERNOON AND EVENING HOURS. WITH SUCH A FLUFFY SNOW
FROM YESTERDAY...COULD BE SOME BLOWING AND DRIFTING OF THE SNOW.
ENJOY THE HEAT ON TUESDAY AS NEXT CLIPPER SYSTEM DROPS INTO THE
AREA. WILL HAVE CHANCES FOR SNOW SHOWERS WITH THIS FEATURE AND
ALONG THE ARCTIC FRONT. NEW ECMWF MORE BULLISH ON TEMPERATURES
WITH TEMPERATURES POSSIBLE REACH THE LOWER TO MIDDLE 30S. DID NOT
STRAY TOO FAR FROM PREVIOUS FORECAST FOR NOW SINCE THERE HAS BEEN
SOME DIFFERENCES IN HOW MUCH WARM AIR WILL MAKE IT INTO THE AREA
AHEAD OF THE ARCTIC FRONT.
BITTER COLD RETURNS FOR WEDNESDAY AND THURSDAY WITH SOME MODIFICATION
IN TEMPERATURES NEXT FRIDAY.
&&
.AVIATION...FOR 12Z TAF ISSUANCE
ISSUED AT 543 AM CST SAT FEB 21 2015
CEILINGS WILL GENERALLY RANGE FROM 2500 TO 3500 FEET
TODAY WITH SCATTERED SNOW SHOWERS AND FLURRIES. THERE IS A CHANCE
THAT AN AREA OF SNOW WITH A FEW HOURS OF IFR CONDITIONS COULD FORM
OVER EASTERN WISCONSIN DURING THE AFTERNOON OR EARLY EVENING BUT
THAT IS NOT A SURE THING. SKIES SHOULD BECOME MOSTLY CLEAR
OVERNIGHT WITH THE EXCEPTION OF SOME LAKE EFFECT CLOUDS NORTH OF
RHINELANDER.
NOTICE TO AIRPORT GROUNDS CREW AND MAINTENANCE...THERE COULD BE A
SIGNIFICANT PERIOD OF BLOWING AND DRIFTING SNOW MONDAY EVENING
THROUGH TUESDAY MORNING. SOUTHWEST WINDS WILL INCREASE TO 15 TO 25
KNOTS WITH GUSTS TO 35 KNOTS POSSIBLE. THIS COULD PRODUCE
SIGNIFICANT BLOWING AND DRIFTING SNOW.
&&
.GRB WATCHES/WARNINGS/ADVISORIES...
WIND CHILL ADVISORY FROM 3 AM TO 11 AM CST SUNDAY FOR WIZ005-
010>012-018-019-030-035-036.
&&
$$
SHORT TERM.....RDM
LONG TERM......ECKBERG
AVIATION.......RDM
FORECAST DISCUSSION FOR ROUTINE MORNING FORECAST ISSUANCE
.SHORT TERM...TODAY...TONIGHT...AND SUNDAY
ISSUED AT 408 AM CST SAT FEB 21 2015
SLOW MOVING ARCTIC FRONT WILL MOVE ACROSS THE AREA THIS MORNING
THEN STALL JUST TO OUR SOUTH AS A WAVE MOVES NORTHEAST ALONG THE
FRONT. THE NAM AND RUC SUGGEST THAT THERE WILL BE SOME LOW LEVEL
CONVERGENCE OVER THE FOX VALLEY AND HAVE FIVE TO TEN HUNDREDTHS OF
AN INCH OF WATER EQUIVALENT. THESE MODELS USUALLY PRETTY GOOD WITH
SMALL SCALE FEATURES SO WENT ALONG WITH THIS IDEA FOR THE MOST
PART. SNOW SHOWERS OR FLURRIES LIKELY ELSEWHERE THIS AFTERNOON.
THIS WILL BE ONE OF THE WARMEST DAYS IN A WEEK OR SO WITH HIGHS IN
THE 20S.
WHATEVER SNOW IS LEFTOVER THIS EVENING SHOULD END BY MIDNIGHT AS
THE FRONT ACCELERATES TO THE SOUTH AND ARCTIC AIR POURS INTO
WISCONSIN. LOWS TONIGHT SHOULD GET BELOW ZERO OVER ALL BUT EAST
CENTRAL WISCONSIN. WINDS SHOULD BE SUFFICIENT TO PRODUCE WIND
CHILLS OF 20 TO 30 BELOW ZERO IN CENTRAL AND NORTHCENTRAL
WISCONSIN WHERE ADVISORIES HAVE BEEN ISSUED. TEMPERATURES SHOULD
BE AROUND 15 DEGREES BELOW NORMAL.
SUNDAY SHOULD BE BLUSTERY AND COLD WITH HIGHS IN THE SINGLE
NUMBERS. SOME PLACES IN THE NORTH COULD STAY JUST BELOW ZERO.
WINDS CHILLS WILL BE 10 TO 20 BELOW ZERO OR COLDER.
.LONG TERM...SUNDAY NIGHT THROUGH FRIDAY
ISSUED AT 408 AM CST SAT FEB 21 2015
WESTERN 500MB RIDGE WILL KEEP REINVENTING ITSELF THROUGH 240 HOURS...
LEADING TO BELOW NORMAL TEMPERATURES ACROSS OUR NECK OF THE WOODS.
THE GOOD NEWS IS THE CALENDAR WILL TURN TO MARCH BY THE END OF
THE FORECAST PERIOD...THUS YOU WOULD THINK TEMPERATURES WOULD
FINALLY RETURN A LITTLE BIT CLOSER TO NORMAL. LAST CHECK OF THE
CLIMATE DATA AT GREEN BAY...WAUSAU AND RHINELANDER INDICATED
TEMPERATURES WERE RUNNING 8 TO 11 DEGREES BELOW NORMAL FOR THE
MONTH. VERY IMPRESSIVE AND POSSIBLY COULD NOT GET ANY WORSE!
THE ROLLER COASTER RIDE WILL BE BOTTOMING OUT SUNDAY NIGHT INTO
MONDAY MORNING. WIND CHILL READINGS HARD TO GAUGE ACROSS THE NORTH
DUE TO THE RIDGE SOUTH OF OUR AREA. SHOULD BE A LIGHT WIND AROUND...
BUT OUR TYPICAL COLD SPOTS LIKE MERRILL...TOMAHAWK AND LAND O LAKES
WILL PROBABLY GO CALM FOR AWHILE AND WOULD NOT MEET THE TRUE WIND
REQUIREMENTS FOR A WIND CHILL ADVISORY OR WARNING. WILL LET LATER
SHIFTS DECIDE IF WIND CHILL WARNING OR ADVISORY WOULD BE NEEDED
FOR THIS AREA...WHILE THE REST OF NORTHEAST AND EAST-CENTRAL
WISCONSIN WILL NEED A WIND CHILL ADVISORY.
INCREASING SOUTHWEST WINDS ON MONDAY CAN BE EXPECTED...ESPECIALLY
LATE IN THE AFTERNOON AND EVENING HOURS. WITH SUCH A FLUFFY SNOW
FROM YESTERDAY...COULD BE SOME BLOWING AND DRIFTING OF THE SNOW.
ENJOY THE HEAT ON TUESDAY AS NEXT CLIPPER SYSTEM DROPS INTO THE
AREA. WILL HAVE CHANCES FOR SNOW SHOWERS WITH THIS FEATURE AND
ALONG THE ARCTIC FRONT. NEW ECMWF MORE BULLISH ON TEMPERATURES
WITH TEMPERATURES POSSIBLE REACH THE LOWER TO MIDDLE 30S. DID NOT
STRAY TOO FAR FROM PREVIOUS FORECAST FOR NOW SINCE THERE HAS BEEN
SOME DIFFERENCES IN HOW MUCH WARM AIR WILL MAKE IT INTO THE AREA
AHEAD OF THE ARCTIC FRONT.
BITTER COLD RETURNS FOR WEDNESDAY AND THURSDAY WITH SOME MODIFICATION
IN TEMPERATURES NEXT FRIDAY.
&&
.AVIATION...FOR 06Z TAF ISSUANCE
ISSUED AT 1052 PM CST FRI FEB 20 2015
CIGS TO MAINLY BE MVFR FOR THE REST OF TNGT THRU SAT MORNING AS A
CDFNT MOVES ACROSS WI. THERE WL STILL BE SOME LIGHT SNOW OR
FLURRIES ACROSS NE WI OVRNGT/SAT MORNING UNTIL THE FNT EXITS THE
AREA WITH VSBYS DROPPING DOWN TO 4 OR 5SM. A WIND SHIFT TO THE NW
SAT MORNING WL PREVAIL FOR THE REST OF SAT WITH CIGS GRADUALLY
IMPROVING TO LOW-END VFR CONDITIONS IN THE AFTERNOON. CANNOT RULE
OUT SOME FLURRIES REDEVELOPING IN THE AFTERNOON DUE TO STEEP LOW-
LEVEL LAPSE RATES. ONCE WE GET PAST SUNSET...DRIER AIR WL ARRIVE
AS HI PRES BEGINS TO BUILD SE FROM CANADA. SKIES ARE EXPECTED TO
GRADUALLY CLEAR SAT NGT WITH VFR CONDITIONS ANTICIPATED.
&&
.GRB WATCHES/WARNINGS/ADVISORIES...
WIND CHILL ADVISORY FROM 3 AM TO 11 AM CST SUNDAY FOR WIZ005-
010>012-018-019-030-035-036.
&&
$$
SHORT TERM.....RDM
LONG TERM......ECKBERG
AVIATION.......AK
AREA FORECAST DISCUSSION
NWS PUEBLO CO
1043 PM MST SUN FEB 22 2015
.UPDATE...
ISSUED AT 800 PM MST SUN FEB 22 2015
STEADY ACCUMULATING SNOW IS NOT LIKELY ACROSS THE FAR E PLAINS AND
PER COORD WITH SURROUNDING WFO/S...I REMOVED THE HILITES FOR THAT
REGION. /HODANISH
&&
.SHORT TERM...(THIS EVENING THROUGH MONDAY)
ISSUED AT 251 PM MST SUN FEB 22 2015
...HEAVY SNOW OVER THE MOUNTAINS CONTINUES...
...SNOW WINDING DOWN TONIGHT FOR THE LOWER ELEVATIONS...
IN GENERAL...FORECAST IS WORKING OUT FAIRLY WELL ACROSS THE CWA.
FORECAST AMOUNTS FOR THE NORTHERN AND EASTERN ZONES WERE TOO
HIGH...AND TOO LOW FOR THE MTS AND SRN ZONES...BUT OVERALL AMOUNTS
ARE NOT TOO SURPRISING. AS THE UPPER TROUGH SHEARS OFF TO THE WEST
OVER CA...AND MID LEVEL WINDS CONTINUE TO VEER TO THE SW AND
W...WILL SEE SNOWFALL GRADUALLY DIMINISH OVER THE ERN PLAINS E OF I-
25 TONIGHT...SO HAVE REDUCED POPS THROUGH TONIGHT IN THAT AREA. WILL
LEAVE A SNOW ADVISORY GOING WITH ADDITIONAL LIGHT ACCUMS OF AN INCH
OR TWO POSSIBLE...AND CONTINUED ICY ROAD CONDITIONS. HIGH RES MODELS
ARE SHOWING THE HEAVIER SNOW GRADUALLY BEING TIED TO THE ERN MTS AND
HIGHER TRRN...AND THIS LOOKS REASONABLE. THERE COULD BE SOME BANDED
PRECIP SPILLING OVER TO PORTIONS OF THE I-25 CORRIDOR...ESPECIALLY W
OF I-25...THROUGH THIS EVENING...SO WILL LEAVE THE WARNING INTACT
FOR THE I-25 ZONES. IN FACT...THE HRRR CONTINUES TO SHOW SN PICKING
UP FOR A BIT EARLY THIS EVENING OVER EL PASO COUNTY BEFORE
DIMINISHING AFTER MIDNIGHT. LATER SHIFT CAN REEVALUATE AND
DOWNGRADE THE WARNING IF IT LOOKS LIKE THIS WILL NOT MATERIALIZE.
OVER THE MTS...SNOW CONTINUES THROUGH TOMORROW. WIND SENSOR IS OUT
AT KCPW...BUT AS MENTIONED IN THE EARLIER UPDATE BLIZZARD CONDITIONS
WERE OCCURRING THERE AND WILL LIKELY CONTINUE THROUGH PERIODS OF
MONDAY BEFORE THINGS BEGIN TO QUIET DOWN. LATEST GUIDANCE SUGGESTS
AN ADDITIONAL 2-3 FEET OVER THE SAN JUANS BY TUESDAY...SO WOULD NOT
BE SURPRISED TO SEE A FEW SPOTS NEAR 4 FEET BY THE TIME THIS
ENDS...AND WITH HIGH WINDS SOME SERIOUS DRIFTING AS
WELL...INCREASING AN UNSTABLE SNOW LOAD ON THE SLOPES AND RESULTING
IN EXTREME AVALANCHE THREAT OVER THE HIGH COUNTRY FOR THE NEXT FEW
DAYS.
INTERESTINGLY...LATEST GUIDANCE IS SHOWING H7 TEMPS OF MINUS 21
DEGREES OVER OUR AREA TONIGHT...SIGNIFICANTLY COLDER THAN WHAT THE
MODELS WERE SHOWING JUST A COUPLE OF DAYS AGO...AND IN LINE WITH THE
ECMWF GUIDANCE FROM A WEEK AGO! THE MUCH COLDER AIR HAS CUT BACK A
BIT ON DENDRITIC SNOW GROWTH...AND LIMITED SNOW AMOUNTS TO SOME
EXTENT FOR OUR ERN ZONES. AS A RESULT OF THE COLDER AIR
ALOFT...EXPECT SOME LOWS CLOSE TO ZERO TONIGHT EVEN WITH THE CLOUD
COVER...AND HAVE REDUCED HIGHS A BIT FOR TOMORROW WITH TEMPS
PROBABLY STAYING IN THE TEENS FOR THE MOST PART.
EXPECT GRADUAL IMPROVEMENT TOMORROW FOR THE PLAINS...AS WRLY FLOW
INCREASES. MODELS ARE SHOWING A LACK OF QPF THERE TOMORROW...BUT
WITH ABUNDANT LOW LEVEL MOISTURE AND CONTINUED SHALLOW UPSLOPE...AM
RELUCTANT TO REMOVE POPS COMPLETELY...SO WILL LEAVE LOW POPS IN
PLACE OVER THE PLAINS. OVER THE MTS...HEAVY SNOW CONTINUES AT TIMES
WITH BLIZZARD CONDITIONS FOR THE ERN SAN JUANS. SAN LUIS VALLEY WILL
BE BETWEEN THE TWO REGIMES AND COULD SEE SOME SHSN...BUT NOTHING
PARTICULARLY HEAVY EXPECTED. WELCOME BACK TO WINTER! ROSE
.LONG TERM...(MONDAY NIGHT THROUGH SUNDAY)
ISSUED AT 251 PM MST SUN FEB 22 2015
MONDAY NIGHT THE UPR LOW IS FORECAST TO MOVE EASTWARD FROM SRN
NV...WITH THE GFS SHOWING THE LOW CENTER OVR NERN AZ BY 12Z TUE AND
THE NAM BEING A LITTLE FARTHER WEST. EITHER WAY...SNOW CONTINUES OVR
THE SWRN CO MTNS. HOWEVER WITH THE GFS BEING FARTHER EAST THAN THE
NAM...PCPN IS ALSO FORECAST TO BE OVR THE SAN LUIS VALLEY AND THE
ERN MTNS...WHILE THE NAM HAS DRY CONDITIONS EVERY BUT THE SW MTNS.
ON TUE THE UPR LOW IS EXPECTED TO CONTINUE AN EASTWARD
TRACK...MOVING ACRS NRN NM...BRINGING MAINLY SOME PCPN CHANCES TO
MAINLY THE FAR SOUTHERN PORTIONS OF THE FORECAST AREA. HIGH TEMPS ON
TUE WL BE A LITTLE WARMER...BUT STILL BELOW AVERAGE...ESPECIALLY
WITH THE SNOW COVER.
TUE NIGHT AND EARLY WED DRY CONDITIONS ARE EXPECTED OVR THE AREA AS
THE UPR LOW MOVES INTO NORTHERN TX. A NEW UPR TROF DROPS INTO THE
STATE FROM THE SOUTH BY LATE WED MORNING...PUSHING MORE COLD AIR
INTO THE AREA. IN THE LATE MORNING OR EARLY AFTERNOON HOURS...PCPN
IS EXPECTED TO SPREAD SOUTH ACRS THE AREA AS WELL...WITH PROBABLY
THE HARDEST HIT AREAS BEING THE EASTERN MTS AND IMMEDIATELY ADJACENT
PLAINS AND THE PALMER DIVIDE. THE GFS AND ECMWF ARE IN PRETTY GOOD
AGREEMENT...KEEPING PCPN ACRS MUCH OF THE SERN PLAINS AND MTNS THRU
THU NIGHT AND MUCH OF FRI AS ANOTHER UPR DISTURBANCE MOVES INTO THE
AREA FROM THE PACIFIC NW. THIS WL BRING THE POTENTIAL FOR SEVERAL
INCHES OF SNOW OVR THE MTNS. UPSLOPE FLOW OVR ERN AREAS WL HELP TO
BRING SEVERAL INCHES TO THE THE WET MTNS...SOUTHERN SANGRES AND THE
ADJACENT PLAINS...WITH MAYBE A COUPLE TO A FEW INCHES ALONG THE I-25
CORRIDOR...AND LIGHTER ACCUMULATIONS OVR THE FAR SERN PLAINS.
UNSETTLE WEATHER IS FORECAST TO CONTINUE NEXT WEEKEND AS ANOTHER
UPR TROF AFFECTS THE STATE...KEEPING THE WEATHER COOL AND BRINGING
PCPN CHANCES TO MUCH OF THE AREA AND THE POTENTIAL FOR SEVERAL
INCHES OF SNOW IN THE MTNS.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT)
ISSUED AT 1042 PM MST SUN FEB 22 2015
MVFR AND IFR CONDITIONS TO CONTINUE AT COS AND PUB WITH LIGHT SNOW
AND FLURRIES ENDING AFT 12Z. LIGHT UPSLOPE FLOW AND ABUNDANT
MOISTURE OVER THE PAST FEW DAYS LOOKS TO KEEP MVFR CIGS IN PLACE
THROUGH THE AFTERNOON...WITH CLEARING SKIES AND VFR CONDITIONS
DEVELOPING THROUGH THE LATE AFTERNOON AND EARLY EVENING WITH
EXPECTED WEAK DOWNSLOPE FLOW.
MVFR AND IFR CONDITIONS WITH OCCASIONAL LIGHT SNOW AND FLURRIES
EXPECTED TO CONTINUE AT ALS THROUGH THE EARLY MORNING HOURS. MVFR
CIGS POSSIBLE THROUGH THE LATE MORNING WITH VFR CONDITIONS EXPECTED
TO DEVELOP THROUGH THE AFTERNOON.
&&
.PUB WATCHES/WARNINGS/ADVISORIES...
WINTER STORM WARNING UNTIL 5 AM MST MONDAY FOR COZ058>063-
072>088.
WINTER WEATHER ADVISORY UNTIL 5 PM MST MONDAY FOR COZ069>071.
WINTER STORM WARNING UNTIL 5 PM MST MONDAY FOR COZ064>067.
BLIZZARD WARNING UNTIL 11 PM MST MONDAY FOR COZ068.
&&
$$
UPDATE...HODANISH
SHORT TERM...28/ROSE
LONG TERM...28
AVIATION...MW
AREA FORECAST DISCUSSION
NWS MELBOURNE FL
350 AM EST MON FEB 23 2015
.DISCUSSION...
TODAY/TONIGHT...COLD FRONT CURRENTLY JUST NORTH OF FL WILL WEAKEN AS
IT SHIFTS SWEETHEART AND EVENTUALLY INTO THE AREA TONIGHT. ANY
FOG/STRATUS INITIALLY OVER THE REGION WILL BURN OFF BY LATE MORN
WITH PARTLY CLOUDY SKIES EXPECTED THROUGH MUCH OF THE DAY. TEMPS
WILL REMAIN ABOVE NORMAL WITH HIGHS RANGING FROM THE UPPER 70S OVER
LAKE AND VOLUSIA COUNTY TO LOW 80S FARTHER SOUTH. MODELS SHOW A
LITTLE HIGHER MOISTURE WORKING INTO NRN AREAS LATER IN THE AFT AHEAD
OF THE FRONT WHICH MAY LEAD TO A FEW SHRAS...SO HAVE INCLUDED SLIGHT
CHANCE POPS NORTH OF ORLANDO. THE LATEST HRRR INDICATES SOME ISO
SHRA ACTIVITY EVEN FARTHER SOUTH BY LATE DAY BUT LOW LEVEL MOISTURE
IS FAIRLY SHALLOW AND MOS POPS REMAIN BELOW MENTIONABLE LEVELS SO
WILL KEEP RAIN CHANCES OUT OF THE FORECAST ELSEWHERE.
AS FRONT MOVES INTO CENTRAL FLORIDA TONIGHT RAIN CHANCES WILL
CONTINUE TO INCREASE SLIGHTLY MAINLY OVER NORTHERN PORTIONS OF THE
AREA. ALSO CLOUD COVER WILL INCREASE AS LOW CLOUD DECK BUILDS IN
BEHIND THE BOUNDARY. SINCE FRONT WILL BE WEAK...OVERNIGHT TEMPS WILL
STAY ABOVE NORMAL WITH LOWS IN THE UPPER 50S TO LOW 60S.
TUE...WEAK COLD FRONT SHOULD SHIFT TO THE SOUTHERN SECTIONS.
FORECAST SOUNDINGS SHOW A SHALLOW COOL AIR MASS WITH CONSIDERABLE
LOW CLOUDINESS ESPECIALLY ACROSS THE NORTH HALF. ISENTROPIC LIFT
WILL BE SHALLOW/WEAK SO EXPECT ONLY SCATTERED LIGHT PRECIP. MAX
TEMPS WILL BE KNOCKED DOWN CONSIDERABLY ACROSS THE NORTH WITH THE
CLOUD COVER AND NORTHERLY WIND FLOW. SOUTHERN SECTIONS WILL HAVE A
LITTLE MORE CLOUDINESS DEVELOPING IN THE AFTERNOON BUT MAX TEMPS
SHOULD STILL BE 80 AROUND OKEECHOBEE.
TUE NIGHT...A WEAK LOW EAST OF THE COASTAL WATERS IS FORECAST TO
PULL AWAY TO THE NORTHEAST BUT THE WEAK/SHALLOW FRONTAL BOUNDARY
SHOULD CONTINUE TO EXTEND ACROSS THE SOUTHERN PENINSULA. MOS POPS
ARE 20-30 PERCENT...BUT THE MAIN CONCERN MAY ACTUALLY TURN OUT TO
BE LOW STRATUS/FOG. WILL NOT MENTION YET AND KEEP POPS AT 20
PERCENT OR LESS.
WED-THU...THE 00Z GFS/ECMWF HAVE COME INTO GOOD AGREEMENT DURING
THIS PERIOD. THE MAIN FEATURE WILL BE A SOUTHERN STREAM SHORTWAVE
TROUGH THAT MOVES ACROSS THE DEEP SOUTH WED WHILE GRADUALLY
DAMPENING OUT. THE ACCOMPANYING SURFACE LOW IS FORECAST TO PUSH
INTO NORTH FLORIDA WED AFTERNOON AND SHIFT TO OFFSHORE THE
CAROLINAS BY 12Z THU.
THE WARM SECTOR WILL ENCOMPASS THE LOCAL AREA AS LOW LEVEL WINDS
BECOME SOUTHERLY AND INCREASE WED INTO WED NIGHT. THE MODELS SHOW
MAIN PRECIP OCCURRING NEAR A WARM FRONT TO OUR NORTH ON WED THEN
AS COLD FRONT DROPS TOWARDS THE AREA OVERNIGHT...A BAND OF
CONVECTION WILL ACCOMPANY IT. THE BAND OF CONVECTION SHOULD SHIFT
INTO SOUTHERN SECTIONS ON THU.
HAVE NOT MADE MUCH CHANGE TO THE PREVIOUS FORECAST WHICH HAS
CHANCE POPS NORTH AND SLIGHT CHANCE IN THE SOUTH WED AND WED
NIGHT...EXCEPT BECOMING LIKELY IN THE NORTH WED NIGHT. CHANCE
POPS SHOULD BE A LITTLE HIGHER IN THE SOUTH ON THU.
WITH QUITE STRONG LOW LEVEL WINDS AS SURFACE LOW MOVES BY JUST TO
OUR NORTH...THE MENTION OF ISOLATED STORMS LOOKS GOOD WED NIGHT
ESPECIALLY NORTH HALF...WITH A SLIGHT CHANCE THAT STORMS COULD BE
STRONG.
FRI-NEXT MON...LARGE HIGH PRESSURE CENTERED OVER THE MID PART OF
THE COUNTRY SHOULD PUSH FRONTAL BOUNDARY INTO THE NORTHERN BAHAMAS
ON FRI BUT THE MODELS SHOW FRONT HANGING UP AND THE ASSOCIATED
MOISTURE FROM IT LIFTING BACK NORTH. THIS WILL ALLOW A MENTION OF
SLIGHT CHANCE TO CHANCE POPS THROUGH THE WEEKEND.
TEMPERATURES GENERALLY EXPECTED TO STAY NEAR TO JUST BELOW SEASONAL
NORMS FRI THEN MODERATE SAT AS BREEZY ONSHORE FLOW DEVELOPS...THEN
BE ABOVE NORMAL BY SUN AS BREEZY ONSHORE CONTINUES. A DEEP LAYER
HIGH PRESSURE RIDGE IS INDICATED OVER THE AREA NEXT MON...SO A
WARM AND DRY DAY LOOKS TO BE ON TAP.
&&
.AVIATION...PATCHY/AREAS OF FOG THROUGH EARLY MORNING WILL PRODUCE
TEMPO IFR/MVFR CONDS THROUGH 13-14Z. ANY FOG SHOULD THEN BURN OFF
WITH VFR CONDS EXPECTED INTO THE AFT. WEAK FRONT MOVING INTO THE
REGION TONIGHT WILL USHER IN A LOWER CLOUD DECK WITH IFR/LIFR CIGS
BUILDING SOUTHWARD OVER THE REGION AS PER LATEST MOS GUIDANCE. SOME
PATCHY FOG MAY ALSO BE POSSIBLE BUT AT THIS TIME NOT EXPECTING
WIDESPREAD LOWER VISIBILITIES.
RAIN CHANCES WILL INCREASE SLIGHTLY INTO LATE DAY AND TONIGHT WITH
THE FRONT BUT POPS ARE LOW ENOUGH TO KEEP MENTION OUT OF THE TAFS
FOR NOW.
&&
.MARINE...
TODAY/TONIGHT...LIGHT TO GENTLE BREEZE EXPECTED TODAY OVER THE
WATERS WITH WINDS INITIALLY OUT OF THE W/SW BECOMING MORE NORTHERLY
AND INCREASING INTO TONIGHT AS A WEAK FRONT MOVES THROUGH THE
REGION.
NORTHERLY SURGE DOES NOT APPEAR AS STRONG AS IT HAD IN PREVIOUS
MODEL RUNS WITH WIND SPEEDS GENERALLY AROUND 15 KNOTS. SEAS BUILDING
TO 6 FEET OVER THE OFFSHORE WATERS NORTH OF THE CAPE BY LATE TONIGHT
STILL LOOKS REASONABLE...SO WILL MAINTAIN THESE WAVE HEIGHTS IN THE
FORECAST.
TUE-FRI...A VERY PROGRESSIVE WEATHER PATTERN WILL LEAD TO QUICKLY
CHANGING WIND FIELDS THROUGH THE PERIOD. A WEAK LOW IS FORECAST
JUST EAST OF THE WATERS TUE WHICH SHOULD PRODUCE A BRIEF PERIOD OF
NORTHERLY WINDS 15-20 KNOTS. THEN ON WED...THE WINDS SHOULD START
OFF LIGHT AND BECOME SOUTHERLY WHILE INCREASING...AS A SURFACE
LOW MOVES TOWARDS NORTH FLORIDA. THE LOW WILL LIFT QUICKLY
NORTHEAST AND SWING A COLD FRONT INTO THE WATERS THU. IN ADDITION
TO INCREASED RAIN CHANCES WED NIGHT AND THU...BREEZY SOUTHERLY
FLOW WILL BECOME NORTHERLY BEHIND THE FRONT THU NIGHT AND CONTINUE
INTO FRI.
&&
.PRELIMINARY POINT TEMPS/POPS...
DAB 78 59 64 52 / 20 30 40 20
MCO 82 61 73 57 / 10 20 30 20
MLB 80 61 72 58 / 10 20 20 30
VRB 81 60 77 58 / 10 10 20 20
LEE 79 59 67 55 / 10 20 40 20
SFB 80 60 68 55 / 20 20 40 20
ORL 81 60 71 57 / 10 20 30 20
FPR 82 60 78 58 / 10 10 20 20
&&
.MLB WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
AM...NONE.
&&
$$
SHORT TERM...WEITLICH
LONG TERM....LASCODY
AREA FORECAST DISCUSSION
NWS CHARLESTON SC
419 AM EST MON FEB 23 2015
.SYNOPSIS...
A COLD FRONT WILL PUSH ACROSS THE REGION TODAY AND BECOME STATIONARY
SOUTH OF THE AREA TONIGHT. DEVELOPING LOW PRESSURE WILL TRACK ALONG
THE STATIONARY FRONT OVER THE ATLANTIC TUESDAY. HIGH PRESSURE WILL
BRIEFLY BUILD IN TUESDAY NIGHT INTO EARLY WEDNESDAY...FOLLOWED BY
STRONGER LOW PRESSURE FROM THE GULF OF MEXICO THAT PASSES OFFSHORE
WEDNESDAY NIGHT. STRONG HIGH PRESSURE CENTERED NORTH OF THE AREA
WILL EXPAND TO BECOME THE PRIMARY FEATURE LATE WEEK INTO NEXT
WEEKEND.
&&
.NEAR TERM /THROUGH TONIGHT/...
TODAY...SHORTWAVE ENERGY EMBEDDED WITHIN THE NEARLY ZONAL FLOW ALOFT
IS HELPING PROVIDE SOME UPPER SUPPORT FOR LOW LEVEL FORCING ALONG A
COLD FRONT THAT STRETCHES FROM EASTERN NORTH CAROLINA BACK TO THE
LOWER MISSISSIPPI VALLEY. THE RESULT IS A LARGE BAND OF WIDESPREAD
RAINFALL THAT IS IMPACTING MUCH OF THE NORTHERN HALF OF THE FORECAST
AREA THIS MORNING. POPS THROUGH THE REMAINDER OF THE MORNING FEATURE
100 POPS TO THE NORTH...RANGING TO SLIGHT CHANCES FAR TO THE SOUTH
AROUND MCINTOSH COUNTY. THE BEST FORCING WILL REMAIN FOCUSED TO THE
NORTH AND THAT IS WHERE THE HEAVIEST RAIN WILL FALL. THEN FOLLOWING
THE RECENT RUNS OF THE HRRR AND THE RAP...THE BULK OF THE
PRECIPITATION WILL COME TO AN END FROM WEST TO EAST IN THE LATE
MORNING TO EARLY AFTERNOON HOURS. TEMPERATURES ARE CURRENTLY QUITE
MILD ACROSS THE REGION...MAINLY IN THE UPPER 50S AND LOW 60S. THESE
VALUES WILL REMAIN STEADY THROUGH DAYBREAK...AND ONLY BEGIN TO FALL
WITH THE SOUTHWARD PROGRESSION OF THE COLD FRONT. BASED ON THE
TIMING IN THE HRRR AND RAP...THE WIND SHIFT AND ASSOCIATED
INFILTRATION OF COOLER AIR WILL BEGIN TAKING PLACE AROUND 13Z OR SO.
HIGH TEMPERATURES FOR THE DAY WILL OCCUR JUST BEFORE THE FRONT
BEGINS ITS SOUTHWARD MARCH...WITH MID 50S IN MOST AREAS AND EVEN
SOME UPPER 50S AND LOW 60S POSSIBLE FOR SOUTHEAST GEORGIA.
TEMPERATURES WILL THEN STEADILY FALL THROUGH THE DAY.
TONIGHT...THE COLD FRONT WILL BECOME NEARLY STATIONARY TO THE SOUTH
AND SOUTHEAST OF THE REGION AS HIGH PRESSURE BEGINS TO BRIDGE ACROSS
THE OHIO VALLEY AND INTO THE MID ATLANTIC. BY LATE TONIGHT...THE
HIGH WILL SETTLE INTO COLD AIR DAMMING POSITION WITH INCREASINGLY
COOL AIR OOZING IN FROM THE NORTHEAST. EARLY IN THE TONIGHT
PERIOD...THE MODELS GENERALLY SHOW A PRECIPITATION LULL PERIOD AS
THE FORCING ALONG THE FRONT IS DISPLACED TO THE SOUTH AND SOUTHEAST
AND THE UPPER SUPPORT WANES. HOWEVER...BY VERY LATE TONIGHT THE NOSE
OF A 80-90 KT 500 MB JET PUSHES IN FROM THE EAST COINCIDENT WITH AN
AREA OF SHALLOW LOW LEVEL ISENTROPIC LIFT. SOME OF THE MODELS SHOW
PRECIPITATION BREAKING OUT CLOSER TO SUNRISE AT THE SAME TIME AS SUB
FREEZING AIR FILTERS IN FROM THE NORTHEAST. SOUNDINGS SHOW THAT
WHATEVER PRECIPITATION DOES FALL WILL LIKELY FALL AS FREEZING
RAIN/DRIZZLE AND THROUGH THE VERY LATE TONIGHT PERIOD WILL MAINLY
IMPACT THE EXTREME NORTH...ALONG AND NEAR THE SANTEE RIVER. THE BULK
OF THIS EVENT WILL THEN OCCUR INTO TUESDAY MORNING. BY LATE
TONIGHT...LOWS WILL REACH THE LOW 30S FOR MUCH OF SOUTHEAST SOUTH
CAROLINA WITH MID TO UPPER 30S IN SOUTHEAST GEORGIA.
&&
.SHORT TERM /TUESDAY THROUGH THURSDAY/...
TUESDAY...THE STALLED OUT FRONT AND ITS ASSOCIATED BAROCLINIC ZONE
WILL BE FOUND NOT FAR OFF THE SE COAST. CHANNELED VORTICITY ARRIVING
IN THE FAST MOVING AND BROADLY CYCLONIC FLOW ALOFT WILL TRIGGER
CYCLOGENESIS A COUPLE HUNDRED MILES OFF THE NE FLORIDA COAST. AT THE
SAME TIME...UPPER DIVERGENCE/DIFLUENCE ASSOCIATED WITH THE EXIT
REGION OF A ROBUST 130 KT JET AND ISENTROPIC ASCENT ON MAINLY THE
280K AND 285K SURFACES /AROUND 1500-2500 FT/ WILL COMBINE WITH
PRODUCE AN EXPANDING AREA OF RAIN ACROSS THE FORECAST AREA. THERE
STILL REMAINS SOME DISPARITIES BETWEEN THE VARIOUS MODEL
GUIDANCE...BUT WE HAVE LEANED TOWARD A SOLUTION MOST SIMILAR TO A
BLEND OF THE NAM...ECMWF AND CANADIAN MODELS AS OPPOSED TO THE GFS.
COLDER AIR WILL BE FILTERING INTO THE REGION AS A TRANSIENT HIGH
PRESSURE WEDGE DEVELOPS BEHIND THE COLD FRONT STALLED OFFSHORE. THIS
WILL CAUSE A CONCERN FOR THE POTENTIAL FOR FREEZING RAIN AND DRIZZLE
OVER SEVERAL PARTS OF THE FORECAST AREA. SOUNDING DATA REVEALS THAT
THE BEST CHANCE FOR FREEZING SURFACE TEMPS AND/OR WET BULBS WILL
OCCUR MAINLY INLAND FROM US-17 IN SC AND OVER JENKINS AND SCREVEN
COUNTIES IN SE GA. THIS INCLUDES PARTS OF THE CHARLESTON AND
BEAUFORT METRO AREAS...AND IT IS IN THESE LOCATIONS WHERE WE HAVE
GONE AHEAD WITH A FREEZING RAIN ADVISORY FROM 4 AM UNTIL 2 PM
TUESDAY. WHILE IT IS CERTAINLY COLD ENOUGH FOR ICE/SNOW
ALOFT...THERE IS A PRONOUNCED WARM NOSE AROUND 900-750 MB WHICH WILL
TURN WILL ALLOW FOR MELTING OF THE FROZEN PRECIP. BUT THERE IS
ENOUGH MOISTURE AND COLDER AIR BELOW TO ALLOW FOR THE LIQUID DROPS
TO REFREEZE. THERE CAN CERTAINLY BE SOME SLEET MIXED IN...BUT THE
BULK OF THE PRECIP LOOKS TO BE FREEZING RAIN AND/OR DRIZZLE. OUR
CONFIDENCE ON THE AMOUNT OF ICING IS MODERATE AT BEST...SINCE WE
HAVE HAD A SHORT DURATION WARM SPELL AND MUCH OF THE PRECIP MAY TURN
OUT BE RATHER LIGHT IN INTENSITY. THAT SAID...WE DO ANTICIPATE A FEW
HUNDREDTHS OF AN INCH OF FREEZING RAIN ON VARIOUS SURFACES. KEEP IN
MIND THAT THE TALLER BRIDGES OF THE AREA CAN FREEZE BEFORE ROAD
SURFACES. THE DON HOLT BRIDGE IN THE CHARLESTON AREA PROBABLY HAS
THE BEST CHANCE OF EXPERIENCING ANY ICING PROBLEMS TUESDAY
MORNING...BUT WE CAN/T ENTIRELY DISCOUNT THE RAVENEL AND WANDO
BRIDGES ALSO GETTING SOME ICE ON THEM. DEPENDING UPON THE INTENSITY
OF THE PRECIP WE MAY NEED TO EXPAND THE ADVISORY A LITTLE FURTHER
SOUTH INTO GEORGIA AT A LATER TIME. TEMPS LOOK TO BE ABOVE FREEZING
IN THE EARLY TO MID AFTERNOON...THUS ANY FREEZING PRECIP WILL CHANGE
OVER TO LIQUID BEFORE TAPERING OFF LATE.
FOR NOW WE BELIEVE THAT THE PRECIP OVER MUCH OF SE GA...ESPECIALLY
TO THE SOUTH OF I-16 WILL BE ALL OR MAINLY LIQUID WITH QPF/S OF 1/10
TO 1/4 INCH TO OCCUR. TEMPS WON/T GO MUCH OF ANYWHERE...EVEN
DROPPING A COUPLE OF DEGREES DUE TO THE PRECIP...AND WE/LL BE MAINLY
IN THE LOWER AND MIDDLE 30S NORTH/NW TO THE LOWER 40S SOUTH.
TUESDAY NIGHT...THE SURFACE WAVE OVER THE ATLANTIC AND THE
ASSOCIATED FORCING PULL AWAY AS A MESO-HIGH BUILDS FROM THE WEST.
THIS WILL TEMPORARILY SHUT OFF THE PRECIP...AND WE WILL NEED TO
WATCH FOR POSSIBLE RE-FREEZING OF THE EARLIER RAINS...ESPECIALLY OVER
THE CHARLESTON QUAD-COUNTY DISTRICT.
WEDNESDAY AND WEDNESDAY NIGHT...A POTENT SHORT WAVE IN THE DESERT SW
TODAY WILL SHIFT THROUGH THE SOUTHERN PLAINS WEDNESDAY AND HEADS
INTO THE SE AT NIGHT. THIS TRIGGERS SURFACE CYCLOGENESIS IN THE
NORTHERN GULF OF MEXICO BEFORE THE LOW TRACKS JUST OFF THE LOCAL
COASTS BY LATE IN THE PERIOD. LARGE SCALE FORCING FROM THESE
FEATURES AND A POWERFUL WEST-EAST 150 KT UPPER JET WILL ALLOW FOR
CONSIDERABLE OVER-RUNNING RAINS TO DEVELOP BY WEDNESDAY
AFTERNOON...BEFORE TAPERING OFF FROM WEST/SW TO EAST/NE LATE
WEDNESDAY NIGHT. THIS PROMISES TO BE A PRETTY GOOD SOAKER...WITH
PWATS OF 1-1.5 INCHES TO PREVAIL. SOME PLACES COULD EASILY ACHIEVE
THESE AMOUNTS GIVEN THAT WE ARE CARRYING CATEGORICAL POPS. RIGHT
NOW IT LOOKS TO BE ALL LIQUID UNLESS THE OVER-RUNNING RAINS ARRIVE
EARLIER THAN EXPECTED. TEMPS WILL REMAIN FAR BELOW NORMAL.
THURSDAY...MUCH DRIER AIR OVERSPREADS THE REGION BEHIND THE EXITING
SHORT AVE AND SURFACE LOW...LEADING TO A DRY BUT CHILLY DAY WITH
TEMPS AGAIN FAR BELOW SEASONAL NORMS.
&&
.LONG TERM /THURSDAY NIGHT THROUGH SUNDAY/...
A HUMONGOUS AND ROBUST 1040 MB CANADIAN HIGH BUILDING OUT OF THE
GREAT PLAINS WILL EXPAND EAST AND SOUTH AND COVERS MUCH OF THE
NATION EAST OF THE ROCKIES...INCLUDING THE LOCAL AREA. THIS LEADS TO
DRY AND CHILLY CONDITIONS INTO FRIDAY...BEFORE THE HIGH SHIFTS INTO
THE ATLANTIC OVER THE WEEKEND AND EARLY NEXT WEEK AND TEMPS BEGIN TO
MODERATE. A COASTAL TROUGH WILL LIKELY FORM DURING THIS TRANSITION
JUST OFF OUR COAST...AND WE LOOK FOR AT LEAST A SMALL CHANCE OF
SHOWERS IN RESPONSE.
&&
.AVIATION /09Z MONDAY THROUGH FRIDAY/...
ONGOING VFR CONDITIONS AT KCHS AND KSAV WILL ONLY LAST A FEW MORE
HOURS AS RAINFALL AND LOWERING CEILINGS BEGIN TO IMPACT THE
TERMINALS. AT KCHS...RAINFALL WILL BECOME STEADY AND PERIODICALLY
MODERATE IN INTENSITY. CEILINGS ARE EXPECTED TO FALL TO MVFR BY
08Z...THOUGH VISIBILITIES IN RAIN COULD BE MVFR OR TEMPORARILY IFR
AT TIMES. CEILINGS WILL CONTINUE TO STEADILY FALL AND REACH IFR
LEVELS AROUND 10Z. THE PRECIPITATION WILL COME TO AN END AROUND
16Z AND THEN LITTLE TO NO RAIN IS EXPECTED THROUGH THE END OF THE
FORECAST. IFR CEILINGS WILL STICK THROUGH THE DAY...LIFTING TO
MVFR IN THE LATE EVENING HOURS. THE MAIN WIND SHIFT WITH THE FRONT
WILL TAKE PLACE AROUND NOON AND WINDS THEREAFTER WILL INCREASE AND
BECOME NORTHERLY. AT KSAV...RAINFALL CHANCES ARE MUCH LOWER AND
THE OVERALL TIMING OF LOWERING CEILINGS WILL BE ABOUT 2-3 HOURS
LATER THAN KCHS. SIMILARLY...IFR CEILINGS WILL SETTLE IN BY LATE
MORNING AND REMAIN THROUGH THE DAY. THE WIND SHIFT WITH THE FRONT
WILL ARRIVE AT KSAV IN THE EARLY AFTERNOON. AN IMPROVEMENT TO MVFR
SHOULD TAKE PLACE CLOSER TO MIDNIGHT.
EXTENDED AVIATION OUTLOOK...FLIGHT RESTRICTIONS OF VARYING
CATEGORIES WILL CONTINUE MUCH OF THE TIME MONDAY NIGHT INTO
THURSDAY...ALTHOUGH INTERLUDES OF VFR ARE POSSIBLE BETWEEN RAIN
EVENTS. ALSO OF NOTE...THERE IS A SLIGHT CHANCE FOR FREEZING/FROZEN
PRECIPITATION LATE MONDAY NIGHT INTO TUESDAY MORNING.
&&
.MARINE...
TODAY AND TONIGHT...A COLD FRONT WILL SINK SOUTHWARD
ACROSS THE REGION AND IS EXPECTED TO PUSH ACROSS THE WATERS MAINLY
IN THE AFTERNOON/EVENING HOURS. BEHIND THE FRONT...A SIGNIFICANT
NORTH TO NORTHEAST SURGE IS EXPECTED TO BEGIN WITH RAPIDLY
INCREASING WINDS AND SEAS. WINDS WILL INCREASE FIRST ACROSS THE
CHARLESTON COUNTY WATERS AND THE CHARLESTON HARBOR IN THE EARLY
AFTERNOON...REACHING THE GEORGIA WATERS IN THE LATE AFTERNOON AND
EARLY EVENING HOURS. THE NEARSHORE WATERS WILL SEE WINDS INCREASE
INTO THE 20 TO 25 KT RANGE...INCLUDING THE CHARLESTON HARBOR...WITH
GUSTS TO 30 KT POSSIBLE FOR THE OUTER GEORGIA WATERS. SMALL CRAFT
ADVISORIES ARE IN EFFECT FOR ALL WATERS THROUGH THE OVERNIGHT. THE
NORTH TO NORTHEAST SURGE WILL CONTINUE TONIGHT IN THE WAKE OF THE
FRONT AS THE PRESSURE GRADIENT TIGHTENS ACROSS THE WATERS. WINDS
WILL LIKELY REACH THEIR PEAK IN THE MID TO LATE EVENING HOURS WITH
GUSTS TO 30 KT POSSIBLE ACROSS ALL WATERS. SEAS WILL CONTINUE TO
INCREASE REACHING 4-6 FT WITHIN 20 NM AND 6-9 FT OUT TO 60 NM.
TUESDAY...ONGOING SMALL CRAFT ADVISORIES WILL CONTINUE INTO THE
AFTERNOON IN ASSOCIATION WITH THE GRADIENT BETWEEN THE ATLANTIC LOW
AND A WEAK INLAND HIGH PRESSURE WEDGE. WHILE WE CAN/T RULE OUT A
LITTLE FREEZING RAIN IN CHARLESTON HARBOR...THE BULK OF THE WET
WEATHER LOOKS TO BE IN THE FORM OF LIQUID.
TUESDAY NIGHT INTO WEDNESDAY...CONDITIONS WILL IMPROVE AS THE
ATLANTIC LOW PULLS AWAY AND ANOTHER AREA OF HIGH PRESSURE ARRIVES
FROM THE WEST. WINDS AND SEAS WILL BE FAR BELOW ANY ADVISORY
THRESHOLDS.
LATE WEDNESDAY INTO THURSDAY...CONDITIONS AGAIN WILL DETERIORATE AS
INTENSIFYING LOW PRESSURE DEVELOPS IN THE GULF OF MEXICO AND TRACKS
OVER OR NEAR THE LOCAL WATERS LATE WEDNESDAY NIGHT/EARLY
THURSDAY...BEFORE PULLING AWAY THURSDAY AFTERNOON. SMALL CRAFT
ADVISORIES ARE AGAIN LIKELY AS A RESULT.
FRIDAY THROUGH SATURDAY...A STRENGTHENING REGION OF CONTINENTAL HIGH
PRESSURE WILL OVERSPREAD THE REGION AND GIVEN COLD ADVECTION AND A
TIGHTENING OF THE PRESSURE GRADIENT ADDITIONAL SMALL CRAFT
ADVISORIES ARE ANTICIPATED.
&&
.CHS WATCHES/WARNINGS/ADVISORIES...
GA...FREEZING RAIN ADVISORY FROM 4 AM TO 2 PM EST TUESDAY FOR
GAZ087-088.
SC...FREEZING RAIN ADVISORY FROM 4 AM TO 2 PM EST TUESDAY FOR
SCZ040-042>045-047>050-052.
MARINE...SMALL CRAFT ADVISORY FROM 1 PM THIS AFTERNOON TO 5 PM EST
TUESDAY FOR AMZ352.
SMALL CRAFT ADVISORY FROM 11 AM THIS MORNING TO 5 PM EST
TUESDAY FOR AMZ350.
SMALL CRAFT ADVISORY FROM 2 PM THIS AFTERNOON TO 5 PM EST
TUESDAY FOR AMZ354.
SMALL CRAFT ADVISORY FROM 2 PM THIS AFTERNOON TO 10 PM EST
TUESDAY FOR AMZ374.
SMALL CRAFT ADVISORY FROM 1 PM THIS AFTERNOON TO 2 PM EST
TUESDAY FOR AMZ330.
&&
$$
NEAR TERM...BSH
SHORT TERM...
LONG TERM...
AVIATION...BSH
MARINE...BSH
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
1201 AM CST MON FEB 23 2015
.UPDATE...
757 PM CST
MADE A COUPLE TWEAKS TO GOING FORECAST`S TEMPERATURES...MAINLY TO
RAISE LOW TEMPS A BIT TONIGHT...ESPECIALLY IN THE URBAN HEAT
ISLAND AND ALSO NUDGED HIGHS UP A BIT MONDAY AS WELL. COLD ARCTIC
AIR CONTINUES TO SLOWLY FILTER INTO THE AREA...BUT GRADIENT IS
REMAINING TIGHT ENOUGH TO KEEP A BIT OF WIND BLOWING WHICH IS
PREVENTING TEMPS FROM TANKING DESPITE THE CLEAR SKY. THE TYPICALLY
COLDER AND MORE SHELTERED AREAS LIKE FOX AND ROCK RIVER VALLEYS
WILL LIKELY SEE WINDS DECOUPLE A BIT MORE THAN OTHER AREAS WITH
TEMPS DROPPING TO AROUND 10 BELOW THERE...BUT DOWNTOWN CHICAGO
WILL PROBABLY ONLY DROP TO AROUND ZERO. THE MINOR ADJUSTMENTS TO
TEMPERATURES AND WINDS SUGGEST THAT MOST AREAS WILL FALL SHORT OF
REACHING WIND CHILL ADVISORY CRITERIA...WITH MOST LIKELY AREAS TO
REACH IT BEING NORTH CENTRAL ILLINOIS INTO THE FAR WESTERN
CHICAGO SUBURBS...WITH WIND CHILLS ELSEWHERE LIKELY "ONLY"
DROPPING TO 15-20 BELOW. ITS POSSIBLE THAT MIDNIGHT SHIFT COULD
KILL WIND CHILL ADVISORY EARLY...BUT JUST NOT COMFORTABLE MAKING
CHANGES TO THE HEADLINE AT THIS TIME.
IZZI
&&
.SHORT TERM...
234 PM CST
TONIGHT THROUGH WEDNESDAY...
COLD TEMPERATURES AND DANGEROUSLY LOW WIND CHILLS TONIGHT AND EARLY
MONDAY ARE THE IMMEDIATE FORECAST CONCERNS IN THE SHORT TERM. WIND
CHILL ADVISORY REMAINS IN EFFECT FOR ENTIRE CWA FROM MIDNIGHT
TONIGHT THROUGH 10 AM CST MONDAY MORNING. COULD EVEN APPROACH
ROCKFORDS RECORD LOW OF -12 F.
1047 MB HIGH PRESSURE CENTERED OVER THE NORTHERN PLAINS THIS
AFTERNOON WILL CONTINUE TO SPREAD SOUTHEAST TO THE MID-MISSISSIPPI
VALLEY TONIGHT. ARCTIC AIR...VERY DRY AIR MASS AND CLEAR SKIES...
AND SLOWLY DIMINISHING WINDS WILL COMBINE TO PRODUCE BITTER COLD
SUB-ZERO TEMPERATURES ACROSS THE FORECAST AREA OVERNIGHT. WITH LOW
TEMPS REACHING FROM -2 TO -14 ACROSS THE CWA AND WINDS JUST UNDER 10
MPH BY MORNING...WIND CHILLS RANGING FROM NEAR 20 BELOW TO NEARLY 30
BELOW ARE EXPECTED BY SUNRISE MONDAY. THUS WIND CHILL ADVISORY
REMAINS IN EFFECT FOR ALL COUNTIES WITH NO CHANGES.
ON MONDAY...THE SURFACE HIGH AND EASTERN PORTION OF THE RIDGE AXIS
WILL CONTINUE TO PUSH SOUTHEAST ACROSS THE AREA IN THE MORNING
BEFORE BECOMING ELONGATED ACROSS THE OHIO VALLEY LATE IN THE DAY.
COLD MORNING MINS AND SHALLOW MIXING IN THE VICINITY OF THE RIDGE
WILL LIKELY KEEP DAYTIME TEMPS IN THE SINGLE DIGITS TO NEAR 10
DEGREES IN MOST AREAS...DESPITE WINDS BECOMING WEST-SOUTHWEST AND
STARTING TO INCREASE DURING THE AFTERNOON. THIS WILL LIKELY RESULT
IN A RECORD LOW-MAX TEMP FOR THE ROCKFORD AREA MONDAY...AS THE
CURRENT RECORD LOW-MAX FOR RFD 2/23 IS A FAIRLY MILD 17 DEGREES.
WIND CHILLS WILL REMAIN SUB-ZERO THROUGH THE DAY...DESPITE MOSTLY
SUNNY SKIES.
ATTENTION THEN TURNS TO ANOTHER STRONG SHORT WAVE TROUGH DIGGING
FROM MANITOBA INTO ONTARIO AND ACROSS THE NORTHERN LAKES INTO
TUESDAY...WHICH RESULTS IN DEEP SURFACE LOW PRESSURE PASSING
NORTHEAST OF THE GREAT LAKES MONDAY NIGHT AND TUESDAY AND TIGHTENING
OF THE SURFACE PRESSURE GRADIENT ACROSS THE MIDWEST. WEST-SOUTHWEST
WINDS WILL BECOME BLUSTERY MONDAY NIGHT SUPPORTING STEADY OR SLOWLY
RISING TEMPERATURES MONDAY NIGHT ESPECIALLY ACROSS THE NORTH WHERE
WINDS WILL BE STRONGEST. TEMPERATURES WILL RISE INTO THE 25-30
DEGREE RANGE DURING THE DAY TUESDAY BEFORE THE COLD FRONT TRAILING
THE CANADIAN LOW MOVES THROUGH LATE IN THE DAY...THOUGH THE GUSTY
SOUTHWEST WINDS TO 35 MPH AT TIMES WILL MAINTAIN A RAW FEEL TO THE
DAY WITH WIND CHILLS IN THE TEENS AT BEST (ABOVE ZERO AT LEAST).
CLOUDS WILL INCREASE TUESDAY MORNING AHEAD OF THE APPROACHING FRONT
WITH SCATTERED SNOW SHOWERS OR FLURRIES AT TIMES DURING THE DAY. THE
COLD FRONT MOVES THROUGH BY EARLY TUESDAY EVENING...WITH BLUSTERY
NORTHWEST WINDS BRINGING COLDER AIR BACK INTO THE REGION AT LEAST IN
A GLANCING NATURE INTO WEDNESDAY WITH SINGLE DIGIT TEMPS TUESDAY
NIGHT AND HIGHS IN THE TEENS AND WIND CHILLS IN THE POSITIVE SINGLE
DIGITS WEDNESDAY. A WEAK CLIPPER SYSTEM IS CURRENTLY PROGGED TO MOVE
JUST WEST OF THE AREA LATE WEDNESDAY AND WEDNESDAY NIGHT...WHICH MAY
BRING SOME LIGHT SNOW TO WESTERN PARTS OF THE CWA. LOW LEVEL WINDS
ALSO LOOK TO VEER MORE NORTH-NORTHEAST WHICH MAY BRING SOME LIGHT
SNOW SHOWERS INTO NORTHWEST INDIANA AND EVEN PARTS OF NORTHEAST
ILLINOIS. NOT TOO EXCITED ABOUT ACCUMULATIONS WITH LAKE EFFECT AT
THIS TIME...AS INVERSION HEIGHTS REMAIN FAIRLY LOW.
RATZER
&&
.LONG TERM...
234 PM CST
THURSDAY THROUGH SUNDAY...
REINFORCEMENT OF ARCTIC AIR CONTINUES THURSDAY AND THURSDAY NIGHT AS
ANOTHER SHORT WAVE TROUGH DIGS SOUTHEAST AND MAINTAINS DEEP LARGE
SCALE TROUGH OVER THE EASTERN CONUS. SURFACE HIGH BUILDS SOUTHEAST
FROM THE NORTHERN PLAINS THURSDAY...INTO DOWNSTATE ILLINOIS BY
FRIDAY MORNING. 850 HPA TEMPS DROP INTO THE -16 TO -20 C RANGE
DURING THE PERIOD WITH LIGHT WINDS OF THE SURFACE RIDGE AND CLEARING
SKIES AGAIN EXPECTED TO PRODUCE SUB-ZERO TEMPERATURES BY SUNRISE
FRIDAY MORNING AND HIGHS ONLY IN THE TEENS FRIDAY...WHICH FOR THE
END OF FEBRUARY IS A GOOD 20-25 DEGREES BELOW OUR NORMAL HIGHS WHICH
WOULD BE NEAR 40 FOR THE END OF THE MONTH.
LONGER RANGE MODEL SOLUTIONS DO OFFER SOME HOPE FOR A LITTLE
MODERATION IN TEMPERATURES NEXT WEEKEND...WITH A TROUGH ELONGATING
AND BECOMING CUT-OFF IN THE SOUTHWEST CONUS AND A BROAD UPPER RIDGE
DEVELOPING ACROSS THE SOUTHEASTERN CONUS SATURDAY AND SUNDAY. THUS
OUR ARCTIC HIGH EVENTUALLY MOVES OFF THE ATLANTIC COAST WITH
SOUTHERLY FLOW DEVELOPING ACROSS THE LOWER AND MIDDLE MISSISSIPPI
VALLEY BY SUNDAY. OF COURSE THIS HELPS TO FEED MILDER AND MORE HUMID
AIR NORTHWARD...FOR A NORTHERN STREAM UPPER TROUGH AND SURFACE LOW
WHICH WOULD ALSO BRING PRECIPITATION TO THE AREA SATURDAY NIGHT AND
SUNDAY. AT THIS DISTANCE HAVE MAINTAINED A CONSERVATIVE APPROACH
WITH TEMPS INTO THE MID-30S SUNDAY AND POTENTIAL FOR SOME SNOW...
THOUGH IF THESE MODEL TRENDS PERSIST IT COULD BE MILDER WITH MIXED
PRECIP OR RAIN ESPECIALLY ACROSS OUR SOUTHEAST.
RATZER
&&
.CLIMATE...
RECORD COLD TEMPERATURES ARE POSSIBLE IN ROCKFORD ON MONDAY
FEBRUARY 23RD.
RECORD LOW FOR 2/23: -12 IN 1910.
RECORD LOW MAX FOR 2/23: 17 IN 1934.
RC
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 06Z...
* LOW-LEVEL WIND SHEAR LATE MONDAY NIGHT.
//DISCUSSION...UPDATED 06Z...
HIGH PRESSURE ACROSS THE MISSOURI RIVER VALLEY EARLY THIS MORNING
WILL MOVE OVER THE AREA MONDAY MORNING AND THEN INCH EAST OF THE
AREA MONDAY NIGHT. WITH THAT WINDS WILL TURN FROM NORTHWEST TO
WEST IN THE MORNING TO SOUTHWEST BY AFTERNOON. WINDS SPEEDS WILL
INCREASE MONDAY NIGHT AS THE PRESSURE GRADIENT TIGHTENS. A STRONG
LOW-LEVEL JET WILL DEVELOP ALOFT LATER MONDAY NIGHT AND SHOULD SET
THE STAGE FOR LOW-LEVEL WIND SHEAR WITHIN THE 900-1500FT LAYER AS
SPEEDS RAPIDLY INCREASE WITH AN INVERSION.
//ORD AND MDW CONFIDENCE...UPDATED 06Z...
* HIGH IN ALL ELEMENTS.
//OUTLOOK FOR ORD/MDW FOR 12Z TUESDAY-12Z SUNDAY...UPDATED 00Z...
TUESDAY...STRONG/GUSTY SW WINDS. MVFR CIGS POSSIBLE LATE.
WEDNESDAY THROUGH SATURDAY...PRIMARILY VFR.
MTF/IZZI
&&
.MARINE...
332 PM CST
HIGH PRESSURE MOVING ACROSS THE NORTHERN PLAINS AND UPPER MIDWEST
THIS AFTERNOON INTO THE EVENING IS ALLOWING FOR NORTHERLY WINDS OF
15 TO 25 KT TO CONTINUE THIS AFTERNOON...WITH THESE SPEEDS TO
LIKELY CONTINUE FOR MUCH OF TONIGHT. THIS HIGH WILL DRIFT
SOUTHEAST THROUGH THE UPPER MIDWEST AND MID MISSISSIPPI VALLEY
TONIGHT THROUGH MONDAY AND THEN REACH THE MID ATLANTIC WEST TO THE
SOUTHERN PLAINS BY EARLY TUESDAY MORNING. AS THIS OCCURS...WINDS
WILL TURN WEST AND THEN SOUTHWEST SLIGHTLY DIMINISHING ON MONDAY
MORNING...BUT THEN INCREASE ONCE AGAIN MONDAY AFTERNOON WITH TO 30
KT WINDS LIKELY LATE IN THE AFTERNOON. WINDS WILL REALLY INCREASE
MONDAY NIGHT INTO TUESDAY OUT AHEAD OF SOUTHWARD MOVING LOW
PRESSURE OVER ONTARIO...WITH GALES LIKELY. HAVE ISSUED A GALE AND
FREEZING SPRAY WARNING OVER THE ENTIRE LAKE MONDAY NIGHT THROUGH
TUESDAY NIGHT AND HAVE NOT ISSUED A GALE WARNING FOR THE NEARSHORE
AT THIS TIME. HOWEVER...THEY DO APPEAR TO BE A POSSIBILITY VERY
EARLY TUESDAY MORNING AND WILL NEED TO CONTINUE MONITORING THIS
PERIOD FOR POSSIBLE PREVAILING GALES...AND EVEN FOR A LONGER
DURATION. DO HAVE HIGH CONFIDENCE WITH THE START TIME OF THE GALES
ACROSS THE LAKE BUT HAVE LOWER CONFIDENCE WITH THE END TIME...WITH
THE GALES POSSIBLY LASTING LONGER INTO TUESDAY NIGHT.
RODRIGUEZ
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...WIND CHILL ADVISORY...ILZ003-ILZ004-ILZ005-ILZ006-ILZ008-ILZ010-
ILZ011-ILZ012-ILZ013-ILZ014-ILZ019-ILZ020-ILZ021-ILZ022-
ILZ023-ILZ032-ILZ033-ILZ039 UNTIL 9 AM MONDAY.
IN...WIND CHILL ADVISORY...INZ001-INZ002-INZ010-INZ011-INZ019 UNTIL 9
AM MONDAY.
LM...GALE WARNING...LMZ080-LMZ669-LMZ671-LMZ673-LMZ675-LMZ777-LMZ779-
LMZ870-LMZ872-LMZ874-LMZ876-LMZ878...9 PM MONDAY TO 3 AM
WEDNESDAY.
HEAVY FREEZING SPRAY WARNING...LMZ080-LMZ669-LMZ671-LMZ673-
LMZ675-LMZ777-LMZ779-LMZ870-LMZ872-LMZ874-LMZ876-LMZ878...9
PM MONDAY TO 3 AM WEDNESDAY.
GALE WARNING...LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-LMZ565-LMZ567-
LMZ868...6 PM MONDAY TO 3 AM WEDNESDAY.
HEAVY FREEZING SPRAY WARNING...LMZ261-LMZ362-LMZ364-LMZ366-
LMZ563-LMZ565-LMZ567-LMZ868...6 PM MONDAY TO 3 AM WEDNESDAY.
GALE WARNING...LMZ740-LMZ741-LMZ742...9 PM MONDAY TO NOON
TUESDAY.
GALE WARNING...LMZ743-LMZ744-LMZ745...MIDNIGHT TUESDAY TO NOON
TUESDAY.
&&
$$
VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)
FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/NWSCHICAGO
WWW.TWITTER.COM/NWSCHICAGO
WWW.YOUTUBE.COM/NWSCHICAGO
Area Forecast Discussion
NATIONAL WEATHER SERVICE LINCOLN IL
1136 PM CST Sun Feb 22 2015
.UPDATE...
ISSUED AT 857 PM CST SUN FEB 22 2015
Strong Arctic high pressure will continue to build into the area
overnight on schedule. Surface temperatures are still above zero,
but wind speeds have been sufficient to drop Wind Chill values
below zero across most of the forecast area. While wind speeds
will die off some overnight as the high approaches and pressure
gradient relaxes, sub-zero air temperatures will allow Wind Chill
values to fall to advisory levels.
Going forecast is in good shape. Only a few tweaks for the latest
hourly trends are required.
&&
.SHORT TERM...(Tonight)
ISSUED AT 240 PM CST SUN FEB 22 2015
Another Arctic air mass settling into our area for tonight and
Monday bringing bitterly cold wind chills tonight through the
mid-morning hours of Monday with values in the -15 to -25 degree
range. Latest upstream observations mostly in the single digits
across north central through northeast Iowa with wind gusts up
to 30 mph at times. Early morning lows are expected to dip to
-2 in the far south to as low as -8 across the north just before
dawn Monday. The center of the Arctic high is forecast by models
to drift into southeast Iowa by 12z Monday with the surface ridge
axis extending northeast into northern Illinois. Forecast soundings
and the latest HRRR model suggests the cloud cover we have over the
area this afternoon will drift east and south later this evening
with mainly some cirrus for the first half of the night and then
a mostly clear sky is expected after midnight most areas. Current
Wind Chill Advisory will remain in place for late tonight through
9AM Monday morning.
&&
.LONG TERM...(Monday through Sunday)
ISSUED AT 240 PM CST SUN FEB 22 2015
As the center of the cold air mass drifts across the area tomorrow,
look for winds to diminish during the day but temperatures will be
slow to rise with afternoon highs struggling to 10 to 15. The high
should be moving off to our east by afternoon and early evening
with our next surface low and cold front tracking across southern
Canada southwest through the Northern Plains. Early in the evening,
surface winds will be light enough for our usual tank with early
evening temperatures before we see a steady or slowly rising trend
across the north and west, while further east with a lighter wind
flow, early morning lows will dip several degrees below zero Monday
night into Tuesday morning. As the deep surface low tracks north
of Lake Superior on Tuesday, a gusty south to southwest wind should
help the mercury climb into the mid 20s far east to the low to mid
30s far west where we should be able to mix out fairly well during the
afternoon. With the better upper forcing remaining well to our north
and very limited moisture, models not showing much if any precip
associated with the boundary as it swings across our area late in
the day, except for the GFS which continues to produce a large area
of 0.01 qpf with this system. Not worth much more than a chance for
flurries and will continue with that for later in the day on Tuesday.
Then we will see another cold air mass build gradually southeast thru
midweek.
The GFS and latest ECMWF continue to show a weak shortwave racing
southeast into the Plains on Wednesday along the periphery of the
next batch of cold air for the remainder of the work week. The
GFS keeps any precip associated with this wave to our west and
south while the latest ECMWF has trended in that direction as well
but does bring in some light QPF late Wednesday/Wednesday evening.
Based on the latest westward shift with the ECMWF, will only have
slight chances Wednesday night for light snow. Colder temperatures
filter into the area again Wednesday night with early morning lows
dropping into the single digits with wind chills dropping to near
-10 by Thursday morning.
And a real surprise here, the well below normal temperatures are
expected to hold on across our area through at least the end of
the work week with daytime highs in the teens and early morning
lows dropping into the single digits with a few below zero readings
again possible early Friday morning. Both the GFS and ECMWF indicate
a significant change to the upper pattern with more of a southwesterly
flow developing over the weekend which will lead to an increasing
threat for precipitation. Models showing more agreement from what
we saw yesterday with snow chances moving in starting on Saturday
night with the threat for snow or rain on Sunday with warming
temperatures. Even seeing some better agreement with the ensemble
members with respect to the pattern change along with timing of
the precip into our area later Saturday through Sunday. Temperatures
will start to turn around on Saturday and Sunday, but still average
below the normal highs of 40 to 45 across the area for late February.
&&
.AVIATION...(For the 06Z TAFS through 06Z Monday night)
ISSUED AT 1136 PM CST SUN FEB 22 2015
VFR aviation weather Condtions are expected to prevail across the
central Illinois terminals through the 06Z TAF valid time.
Mid/high level CIGS will gradually diminish with time, with mostly
clear skies expected by midday Monday. Northerly breezes from
10-15 kts tonight will become light/variable by Monday afternoon
as high pressure builds across the area. Then, as the high begins
to pull away Monday evening, winds will swing around to the
southwest.
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
WIND CHILL ADVISORY until 9 AM CST Monday FOR ILZ027>031-036>038-
040>057-061>063-066>068-071>073.
&&
$$
UPDATE...Bak
SHORT TERM...Smith
LONG TERM...Smith
AVIATION...Bak
AREA FORECAST DISCUSSION
NWS PADUCAH KY
1128 PM CST SUN FEB 22 2015
.SHORT TERM...(THIS EVENING THROUGH TUESDAY NIGHT)
ISSUED AT 235 PM CST SUN FEB 22 2015
MAIN ISSUE OF CONCERN IN THE SHORT TERM IS THE WIND CHILL ADVISORY
FOR LATE TONIGHT INTO MONDAY MORNING. THE LATEST SHORT TERM
GUIDANCE KEEPS THE STRONGEST WINDS AND COLDEST TEMPERATURES ACROSS
PORTIONS OF SOUTHEAST MISSOURI AND MOST OF SOUTHERN ILLINOIS.
AFTER COLLABORATING WITH WFOS LSX AND LMK DECIDED TO EXPAND THE
ADVISORY A ROW OF COUNTIES FARTHER SOUTH ACROSS ILLINOIS AND THEN
FROM PERRY SOUTHWARD THROUGH SCOTT AND STODDARD IN MISSOURI. IT
LOOKS A LITTLE FUNKY IN MISSOURI...BUT THAT IS DUE TO THE CORE OF
STRONGER WINDS IN THAT REGION. THE WIND CHILLS CURRENTLY FORECAST
OVER SOUTHWEST INDIANA AND ADJACENT PORTIONS OF WEST KENTUCKY DO
NOT QUITE GET DOWN TO 10 BELOW...BUT LEFT THAT ALONE BECAUSE IT
WILL BE CLOSE.
ALTHOUGH WINDS ARE EXPECTED TO BE LIGHT MONDAY NIGHT...SOUTH WINDS
WILL INCREASE QUICKLY TUESDAY MORNING AND WITH THE LOWS WELL INTO
THE SINGLE DIGITS...MUCH OF SOUTHERN ILLINOIS AND SOUTHWEST
INDIANA MAY SEE SOME NEGATIVE WIND CHILLS FOR A FEW HOURS TUESDAY
MORNING. WILL GIVE THIS A MENTION IN THE HWO.
KEPT A MENTION OF FLURRIES IN THE FORECAST LATE THIS AFTERNOON AND
EVENING ROUGHLY ALONG AND SOUTH OF A LINE FROM VAN BUREN MISSOURI
TO MURRAY KENTUCKY. THE HRRR AND WRF RUNS REALLY DRY UP ANY ECHOES
AS THEY ENTER OUR AREA...AND THERE HASN`T BEEN ANY REPORTS OF SNOW
REACHING THE GROUND THIS SIDE OF KJLN. WON`T BE COMPLETELY
SURPRISED TO SEE A FEW FLURRIES...BUT MEASURABLE SNOWFALL IS
HIGHLY UNLIKELY.
TEMPERATURES HAVE REMAINED NEARLY STEADY ACROSS THE REGION
TODAY. FIGURE THAT COLD ADVECTION WILL KICK IN AS WE HEAD INTO THE
EVENING HOURS...BUT ENDED UP RAISING LOWS A BIT FOR TONIGHT. MOS
GUIDANCE IS GIVING QUITE A RANGE FOR FIRST PERIOD LOWS.
LOOKING UPSTREAM THIS AFTERNOON...IT APPEARS THAT GUIDANCE FOR
HIGHS ON MONDAY IS A BIT TOO COLD. LEANED TOWARD THE LESS COLD
NAM/MET NUMBERS...BUT IT WILL STILL STRUGGLE TO GET THROUGH THE
TEENS IN MOST LOCATIONS. WIND CHILLS WILL REMAIN IN THE SINGLE
DIGITS ABOVE ZERO THROUGH THE AFTERNOON.
NOT SURE IF MID/HIGH CLOUDS WILL BE THICK ENOUGH TO HOLD
TEMPERATURES UP MUCH MONDAY NIGHT OR NOT. WINDS SHOULD BE LIGHT OR
CALM WITH HIGH PRESSURE OVERHEAD...SO IT WILL BE ANOTHER COLD ONE.
DEFINITELY WENT TO THE COLD SIDE OF GUIDANCE MONDAY NIGHT.
SOUTHWEST WINDS WILL INCREASE ACROSS THE AREA TUESDAY...SO A
DECENT WARM UP IS FORECAST. UNFORTUNATELY WITH TEMPERATURES
STARTING OFF SO COLD...IT WILL STRUGGLE TO GET TO THE FREEZING
MARK.
A DISTURBANCE WILL DIVE SOUTHEAST THROUGH THE GREAT LAKES TUESDAY
NIGHT. THIS WILL BRING AN INCREASE IN CLOUDS AND A WEAK COLD
FRONTAL PASSAGE THROUGH OUR REGION. LOWS TUESDAY NIGHT WILL
ACTUALLY BE MILD...RELATIVELY SPEAKING. SOME LOCATIONS WILL STAY
ABOVE 20 ALL NIGHT.
.LONG TERM...(WEDNESDAY THROUGH SUNDAY)
ISSUED AT 235 PM CST SUN FEB 22 2015
ANOTHER SURGE OF COLD HIGH PRESSURE WILL BUILD SOUTHEAST WEDNESDAY
INTO WEDNESDAY NIGHT BEHIND A WEAK COLD FRONT. THE CENTER OF THE
HIGH WILL MOVE SOUTHEAST THROUGH THE END OF THE WORK WEEK AND SETTLE
OVER THE OHIO VALLEY BY 00Z SATURDAY. TEMPERATURES WILL AGAIN DROP
OFF TO EVEN COLDER THAN SEASONAL NORMALS, WITH HIGHS THURSDAY AND
FRIDAY ONLY IN THE 20S WITH LOWS IN THE SINGLE DIGITS TO MIDDLE
TEENS.
MODELS SHOW THE HIGH DRIFTING EASTWARD FOR THE EARLY PART OF THE
WEEKEND. TEMPERATURES WILL MODERATE BACK IN THE 30S AHEAD OF OUR
NEXT WEATHER SYSTEM. ECMWF AND GFS DIFFER ON TIMING AND TRACK OF A
LOW PRESSURE SYSTEM, WITH ECMWF BEING THE FASTER OF THE MODELS WITH
MORE SUBSTANTIAL QPF. ECMWF SHOWS WIDESPREAD PRECIPITATION ACROSS
THE PAH FORECAST AREA SATURDAY NIGHT, WHILE GFS JUST SHOW MINIMAL
QPF REACHING INTO OUR SOUTHERN COUNTIES LATE SATURDAY NIGHT. BY
SUNDAY BOTH MODELS SHOW DECENT QPF ACROSS THE ENTIRE PAH FA. JUST
WENT WITH SLIGHT CHANCE POPS FOR LIGHT SNOW SATURDAY NIGHT,
INCREASING TO CHANCE POPS FOR RAIN ON SUNDAY. BOTH MODELS YESTERDAY
SHOWED THIS SYSTEM AFFECTING OUR REGION FRIDAY NIGHT INTO SATURDAY,
SO WE STILL ARE FAIRLY LOW CONFIDENCE ON TIMING. THE LATER TIMING
DOES AT LEAST ALLOW SOME "WARMER" TO GET INTO OUR AREA AHEAD OF THE
SYSTEM, THUS LEADING TO LESS WINTRY PRECIP.
&&
.AVIATION...
ISSUED AT 1128 PM CST SUN FEB 22 2015
VFR CONDITIONS TO DOMINATE WITH WEAKENING SURFACE WIND GRADIENT
ACROSS THE WFO PAH TAF SITES. WIND GUSTS SHOULD DIMINISH ACROSS
THE AREA BY 12Z.
&&
.PAH WATCHES/WARNINGS/ADVISORIES...
IL...WIND CHILL ADVISORY UNTIL 9 AM CST MONDAY FOR ILZ075>078-080>091.
MO...WIND CHILL ADVISORY UNTIL 9 AM CST MONDAY FOR MOZ076-086-087-110-
111.
IN...WIND CHILL ADVISORY UNTIL 9 AM CST MONDAY FOR INZ081-082-085>088.
KY...WIND CHILL ADVISORY UNTIL 9 AM CST MONDAY FOR KYZ010-014-015-
018>020.
&&
$$
SHORT TERM...DRS
LONG TERM...RST
AVIATION...SMITH
AREA FORECAST DISCUSSION
NWS WAKEFIELD VA
411 AM EST MON FEB 23 2015
.SYNOPSIS...
A FRONTAL BOUNDARY STALLS ACROSS THE CAROLINA COAST TONIGHT AND
MONDAY AS A WEAK AREA OF LOW PRESSURE MOVES EAST ALONG IT. AN
ARCTIC COLD FRONT WILL PUSH ACROSS THE AREA MONDAY MORNING. HIGH
PRESSURE RETURNS THROUGH MID WEEK.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
LATEST RADAR TRENDS SUPPORT WHAT 00Z MODELS HAVE TRENDED
TOWARDS: A BAND OF PRECIP FORMING NORTH OF THE MAIN AXIS OF DEEPER
MOISTURE OVER NE NC. THUS...HAVE BUMPED POPS UP TO LIKELY FOR A
FEW HRS (MAINLY FROM 12-15Z) ACRS CENTRAL VA INCLUDING METRO RIC.
PTYPE INITIALLY LIGHT RAIN BUT SHOULD TRANSITION QUICKLY TO MAINLY
SNOW BY 12Z. THIS BAND EXPECTED TO SHIFT SE THROUGH THE LATER AM
HRS...AND ALLOW RAIN TO CHANGE TO SLEET/SNOW INTO HAMPTON ROADS
AND NE NC SOMETIME AROUND 15Z. LIGHT ACCUMULATIONS POSSIBLE...MAY
ISSUE AN SPS BUT NO ADSY AS AMOUNTS SHOULD BE WELL BELOW CRITERIA.
PREV DISC...
18Z/22 GFS AND RUC SUGGEST A LITTLE BETTER CHC FOR A PD OF LGT
PCPN OVR SRN VA/NE NC LT TNGT INTO MID/LT MRNG HRS MON. HAVE
ADJUSTED POPS UP ACRS SRN/SE VA AND NE NC. ADDED 30-50% CHC SN N
OF THE VA/NC BORDER TO ABT FVX-LFI/SRN PORTION OF ERN SHORE...W/
PSBL ACCUM LESS THAN 1 INCH. MIXED PTYPC PSBL ACRS NE NC...PTNTLLY
BECOMING SN BEFORE ENDING LT MON MRNG/EARLY AFTN. ANY PCPN WILL BE
ARRIVING W/ LO LVL CAA INCRSG AS NEXT CDFNT PUSHES THROUGH THE RGN.
TEMPS ONLY RISE A FEW DEGREES FROM 12Z READINGS THEN REMAIN
STEADY OR SLOWLY FALL BACK INTO THE 20S IN THE AFTRN AS THE NEXT
ARCTIC HIGH PRESSURE BUILDS INTO THE REGION ON GUSTY N-NW WINDS.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH WEDNESDAY/...
MSTLY CLR TO PT CLDY SKIES MONDAY NIGHT AS RIDGE AXIS BUILDS OVER
THE FA. RECORD LOWS IN JEOPARDY AS WINDS WEST OF THE BAY DECOUPLE
ALLOWING FOR GOOD RADIATIONAL COOLING. WIND CHILL VALUES ALONG THE
COAST ARE EXPECTED TO REMAIN ABOVE ADVISORY CRITERIA. ONLY THING
THAT MIGHT PREVENT THE RECORDS FROM FALLING IS SOME MID / HIGH
LEVEL CLOUDS NOTED IN TSCTNS. LOWS 5-10 EASTERN SHORE...10-15
ELSEWHERE EXCEPT M-U TEENS SERN BEACH AREAS. SEE CLI SECTION BELOW
FOR TUES RECORD TMPS.
PT TO MSTLY SUNNY TUESDAY. COLD AS H85 TMPS ONLY SUPPORT HIGHS IN THE
U20S-M30S. MODELS SHOW WEAK AREA OF LOW PRESSURE (TROF) OFF THE SERN
COAST TUESDAY NIGHT. EXPECT THE SGNFCNT MOISTURE TO STAY ALONG OR
EAST OF THE CAROLINA COAST. WENT WITH A BIT MORE CLOUD COVERAGE OVER
THE EAST THUS PT TO MSTLY CLDY SKIES AS AN UPPER LEVEL TROF SWINGS
ACROSS THE NERN STATES. NOT AS COLD AS SW WINDS HOLD LOWS IN THE 20S.
THE LOW PULLS FURTHER EAST AND OFF THE COAST WED. MILDER UNDER PT TO
MSTLY SUNNY SKIES. WEST WINDS ALLOW TMPS TO WARM BACK INTO THE 40S.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/...
THE LONG TERM WILL BRING SUBTLE CHANGES TO THE WEATHER. WHILE BELOW
NORMAL TEMPERATURES WILL CONTINUE...THE COLD WILL NOT BE AS BRUTAL
AS THE PAST WEEK. A SPLIT FLOW PATTERN WILL BRING A MORE ACTIVE
SOUTHERN STREAM WILL BRING LOW PRESSURE SYSTEMS PASSING TO THE SOUTH
OF THE AREA BUT WIDESPREAD PRECIPITATION IS NOT EXPECTED.
FOLLOWING THE PASSAGE OF AN ARCTIC COLD FRONT MID WEEK...A LOW
PRESSURE SYSTEM MOVES OFF THE SOUTHEAST COAST WEDNESDAY NIGHT. PCPN
SHOULD GENERALLY BE TO THE SOUTH OF THE AREA. GUIDANCE HAS VARIOUS
CHANCES FOR PCPN SATURDAY THROUGH SUNDAY WITH RAIN OR SNOW SATURDAY
AND SATURDAY NIGHT AND RAIN SUNDAY. A COLD FRONT APPROACHES FROM THE
WEST LATE IN THE WEEKEND. KEPT POPS AT 30 PERCENT DURING THE
WEEKEND.
HIGH TEMPERATURES IN THE UPR 20S TO 30S THURSDAY AND FRIDAY WARM TO
THE UPR 40S AND 50S BY SUNDAY. LOWS WILL BE MAINLY IN THE
20S...WARMING TO THE MID 30S NEAR THE SE VA/NE NC COAST SUNDAY
MORNING.
&&
.AVIATION /09Z MONDAY THROUGH FRIDAY/...
LIGHT FLOW IN BETWEEN STALLED BOUNDARY TO THE SOUTH AND HIGH
PRESSURE WELL OFF TO THE NW OF THE REGION HAS ALLOWED AREAS OF
DENSE FOG TO PERSIST NEAR THE COAST. EXPECT THIS TO CONTINUE
THROUGH ABOUT 08-09Z...WITH VSBYS IMPROVING THEREAFTER AS NNE
WINDS INCREASE. HOWEVER...WAVE OF LOW PRESSURE ALONG THAT BOUNDARY
TO THE SOUTH WILL BRING SOME INCREASE IN DEEPER MOISTURE AND A CHC
FOR RAIN CHANGING TO SNOW OR SNOW/SLEET MIX THROUGH THE MORNING
FROM NW TO SE SO THAT AFTER 15Z ALL AREAS ARE EXPERIENCING MAINLY
SNOW/SLEET. PRECIP SHOULD END AT KRIC AFTER 15 TO 16ZZ...BUT
PERSIST UNTIL AT LEAST 18Z AT KORF/KPHF/KECG. CIGS/VSBYS WILL
REMAIN IFR TO LOW END MVFR WITH THE PRECIP...THEN IMPROVE THROUGH
THE AFTN. WINDS WILL BECOME STRONG FROM THE NNE AFTER 12Z WITH
GUSTS TO 20 KT INLAND AND 25-30 KT NEAR THE COAST. WINDS DIMINISH
TONIGHT.
OUTLOOK...MAINLY DRY...COLD WITH VFR CONDITIONS EXPECTED TUE AND
WED. ANOTHER SYSTEM PASSES BY TO THE SOUTH WED NIGHT/THU AND MAY
BRING SOME SNOW TO MAINLY SE VA/NE NC SITES.
&&
.MARINE...
RAISED GALE WARNING FOR NC COASTAL WATERS...AS THERE LOOKS TO BE A
PERIOD OF 6-9 HRS OF GUSTS TO AT LEAST 35 KT THIS AFTN/EARLY
EVENING WHEN SFC LOW PUSHES ENE OFF THE NC COAST AND INTENSIFIES.
RAISED SEAS TO 7-10 FT IN THESE AREAS AS WAVEWATCH TYPICALLY WELL
UNDERDONE IN THIS NNE WIND PATTERN. STRONG SCA`S ELSEWHERE WITH
20-25 KT G30 KT. WILL LIKELY SEE A FEW GUSTS TO GALE FORCE BRIEFLY
LATER TODAY FOR SRN VA CSTL WATERS AND MOUTH OF BAY BUT DURATION
AND COVERAGE LOOKS TOO LOW ATTM TO RAISE GALES.
SEAS WILL BLD TO 5-8 FT ACRS REMAINDER OF CSTL WATERS AND WAVES WILL
BLD TO 3-5 FT IN THE CHES BAY. HI PRES BLDS ACRS THE REGION MON
NGT/TUE...THEN MOVES OFFSHR TUE AFTN/TUE NGT...AHEAD OF NEXT
ARCTIC FRONT. THIS FRONT WILL CROSS THE AREA ON WED...FOLLOWED BY
ANOTHER SURGE OF COLD AIR FOR THU AND FRI.
&&
.TIDES/COASTAL FLOODING...
LOW WATER ADVISORIES HAVE ENDED AS THE NEGATIVE ANOMALIES HAVE
DIMINISHED...BUT WATER LEVELS GENLY REMAIN BELOW ASTRONOMICAL
TIDES THROUGH MIDWEEK.
&&
.CLIMATE...
NORFOLK`S LOW TEMPERATURE OF 9 DEGREES ON FEB 20 WAS THE COLDEST
FOR SO LATE IN THE SEASON. THE MINUS 4 DEGREE READING AT SALISBURY
ON FEB 21ST IS NOW THE ALL TIME LOW FOR THE MONTH OF FEBRUARY.
THE CURRENT AVERAGE TEMPERATURES FOR THE MONTH OF FEBRUARY AT
BOTH RICHMOND AND NORFOLK PLACE THEM IN THE TOP 10 COLDEST. WITH
ADDITIONAL COLD TEMPERATURES EXPECTED NEXT WEEK...IT IS VERY
LIKELY THAT BOTH SITES WILL HAVE AVERAGE TEMPERATURES IN THE TOP
10 COLDEST FEBRUARYS ON RECORD...PERHAPS IN THE TOP 5 COLDEST.
RECORD LOW TEMPERATURES FOR TUESDAY 2/24:
RIC...11 IN 1914
ORF...16 IN 1947
SBY...10 IN 1934
ECG...19 IN 1947
&&
.AKQ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
NC...NONE.
VA...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 7 PM EST THIS EVENING FOR
ANZ635>637.
SMALL CRAFT ADVISORY UNTIL 1 AM EST TUESDAY FOR ANZ630>632-634-
650-652-654.
SMALL CRAFT ADVISORY UNTIL 4 AM EST TUESDAY FOR ANZ633.
SMALL CRAFT ADVISORY UNTIL 10 PM EST THIS EVENING FOR ANZ638.
SMALL CRAFT ADVISORY UNTIL 7 AM EST TUESDAY FOR ANZ656.
GALE WARNING UNTIL 10 PM EST THIS EVENING FOR ANZ658.
&&
$$
SYNOPSIS...ALB/MPR
NEAR TERM...BMD/MPR
SHORT TERM...MPR
LONG TERM...LSA
AVIATION...LKB
MARINE...LKB
TIDES/COASTAL FLOODING...
CLIMATE...
AREA FORECAST DISCUSSION
NWS WAKEFIELD VA
205 AM EST MON FEB 23 2015
.SYNOPSIS...
A FRONTAL BOUNDARY STALLS ACROSS THE CAROLINA COAST TONIGHT AND
MONDAY AS A WEAK AREA OF LOW PRESSURE MOVES EAST ALONG IT. AN
ARCTIC COLD FRONT WILL PUSH ACROSS THE AREA MONDAY MORNING. HIGH
PRESSURE RETURNS THROUGH MID WEEK.
&&
.NEAR TERM /THROUGH TODAY/...
LOCALLY DENSE FOG HAS FORMED FM PORTIONS OF THE ERN SHORE TO CSTL
SECTIONS IN SE VA (AND OVR THE ADJACENT WTRS). HAVE COVERED THE
FOG W/ A SPECIAL WEATHER STATEMENT ON LAND...AND DENSE FOG
ADVISORY OVR THE WTRS (UNTIL ABT 09Z/23). OTRW...VRB CLDS ACRS THE
AREA WILL TEMPS CONTG A SLOW DROP THROUGH THE 30S/40S. SOME DRIER
AIR WILL BE SPREADING SLOWLY INTO THE RGN FM THE NW BY LT
TNGT...SO THE FOG IS XPCD TO DISSIPATE. LO TEMPS MNLY 30 TO 35F.
18Z/22 GFS AND RUC SUGGEST A LITTLE BETTER CHC FOR A PD OF LGT
PCPN OVR SRN VA/NE NC LT TNGT INTO MID/LT MRNG HRS MON. HAVE
ADJUSTED POPS UP ACRS SRN/SE VA AND NE NC. ADDED 30-50% CHC SN N
OF THE VA/NC BORDER TO ABT FVX-LFI/SRN PORTION OF ERN SHORE...W/
PSBL ACCUM LESS THAN 1 INCH. MIXED PTYPC PSBL ACRS NE NC...PTNTLLY
BECOMING SN BEFORE ENDING LT MON MRNG/EARLY AFTN. ANY PCPN WILL BE
ARRIVING W/ LO LVL CAA INCRSG AS NEXT CDFNT PUSHES THROUGH THE RGN.
TEMPS ONLY RISE A FEW DEGREES FROM 12Z READINGS THEN REMAIN
STEADY OR SLOWLY FALL BACK INTO THE 20S IN THE AFTRN AS THE NEXT
ARCTIC HIGH PRESSURE BUILDS INTO THE REGION ON GUSTY N-NW WINDS.
&&
.SHORT TERM /TONIGHT THROUGH WEDNESDAY/...
MSTLY CLR TO PT CLDY SKIES MONDAY NIGHT AS RIDGE AXIS BUILDS OVER
THE FA. RECORD LOWS IN JEOPARDY AS WINDS WEST OF THE BAY DECOUPLE
ALLOWING FOR GOOD RADIATIONAL COOLING. WIND CHILL VALUES ALONG THE
COAST ARE EXPECTED TO REMAIN ABOVE ADVISORY CRITERIA. ONLY THING
THAT MIGHT PREVENT THE RECORDS FROM FALLING IS SOME MID / HIGH
LEVEL CLOUDS NOTED IN TSCTNS. LOWS 5-10 EASTERN SHORE...10-15
ELSEWHERE EXCEPT M-U TEENS SERN BEACH AREAS. SEE CLI SECTION BELOW
FOR TUES RECORD TMPS.
PT TO MSTLY SUNNY TUESDAY. COLD AS H85 TMPS ONLY SUPPORT HIGHS IN THE
U20S-M30S. MODELS SHOW WEAK AREA OF LOW PRESSURE (TROF) OFF THE SERN
COAST TUESDAY NIGHT. EXPECT THE SGNFCNT MOISTURE TO STAY ALONG OR
EAST OF THE CAROLINA COAST. WENT WITH A BIT MORE CLOUD COVERAGE OVER
THE EAST THUS PT TO MSTLY CLDY SKIES AS AN UPPER LEVEL TROF SWINGS
ACROSS THE NERN STATES. NOT AS COLD AS SW WINDS HOLD LOWS IN THE 20S.
THE LOW PULLS FURTHER EAST AND OFF THE COAST WED. MILDER UNDER PT TO
MSTLY SUNNY SKIES. WEST WINDS ALLOW TMPS TO WARM BACK INTO THE 40S.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/...
THE LONG TERM WILL BRING SUBTLE CHANGES TO THE WEATHER. WHILE BELOW
NORMAL TEMPERATURES WILL CONTINUE...THE COLD WILL NOT BE AS BRUTAL
AS THE PAST WEEK. A SPLIT FLOW PATTERN WILL BRING A MORE ACTIVE
SOUTHERN STREAM WILL BRING LOW PRESSURE SYSTEMS PASSING TO THE SOUTH
OF THE AREA BUT WIDESPREAD PRECIPITATION IS NOT EXPECTED.
FOLLOWING THE PASSAGE OF AN ARCTIC COLD FRONT MID WEEK...A LOW
PRESSURE SYSTEM MOVES OFF THE SOUTHEAST COAST WEDNESDAY NIGHT. PCPN
SHOULD GENERALLY BE TO THE SOUTH OF THE AREA. GUIDANCE HAS VARIOUS
CHANCES FOR PCPN SATURDAY THROUGH SUNDAY WITH RAIN OR SNOW SATURDAY
AND SATURDAY NIGHT AND RAIN SUNDAY. A COLD FRONT APPROACHES FROM THE
WEST LATE IN THE WEEKEND. KEPT POPS AT 30 PERCENT DURING THE
WEEKEND.
HIGH TEMPERATURES IN THE UPR 20S TO 30S THURSDAY AND FRIDAY WARM TO
THE UPR 40S AND 50S BY SUNDAY. LOWS WILL BE MAINLY IN THE
20S...WARMING TO THE MID 30S NEAR THE SE VA/NE NC COAST SUNDAY
MORNING.
&&
.AVIATION /07Z MONDAY THROUGH FRIDAY/...
LIGHT FLOW IN BETWEEN STALLED BOUNDARY TO THE SOUTH AND HIGH
PRESSURE WELL OFF TO THE NW OF THE REGION HAS ALLOWED AREAS OF
DENSE FOG TO PERSIST NEAR THE COAST. EXPECT THIS TO CONTINUE
THROUGH ABOUT 08-09Z...WITH VSBYS IMPROVING THEREAFTER AS NNE
WINDS INCREASE. HOWEVER...WAVE OF LOW PRESSURE ALONG THAT BOUNDARY
TO THE SOUTH WILL BRING SOME INCREASE IN DEEPER MOISTURE AND A CHC
FOR RAIN CHANGING TO SNOW OR SNOW/SLEET MIX THROUGH THE MORNING
FROM NW TO SE SO THAT AFTER 15Z ALL AREAS ARE EXPERIENCING MAINLY
SNOW/SLEET. PRECIP SHOULD END AT KRIC AFTER 15 TO 16ZZ...BUT
PERSIST UNTIL AT LEAST 18Z AT KORF/KPHF/KECG. CIGS/VSBYS WILL
REMAIN IFR TO LOW END MVFR WITH THE PRECIP...THEN IMPROVE THROUGH
THE AFTN. WINDS WILL BECOME STRONG FROM THE NNE AFTER 12Z WITH
GUSTS TO 20 KT INLAND AND 25-30 KT NEAR THE COAST. WINDS DIMINISH
TONIGHT.
OUTLOOK...MAINLY DRY...COLD WITH VFR CONDITIONS EXPECTED TUE AND
WED. ANOTHER SYSTEM PASSES BY TO THE SOUTH WED NIGHT/THU AND MAY
BRING SOME SNOW TO MAINLY SE VA/NE NC SITES.
&&
.MARINE...
HAVE DECIDED TO ISSUE A SCA FOR THE ENTIRE WTRS STARTING LATE TNGT
AND LASTING THRU MON EVENG/MON NGT. THERE IS STILL POTENTIAL FOR
GALE GUSTS DURING LATE MON MORNG/AFTN TIMEFRAME AT THE MOUTH OF THE
BAY AND CSTL WTRS S OF CAPE CHARLES...DUE TO STRONGER PRESSURE
GRADIENT IN THIS AREA. BUT...FOR NOW WENT WITH A STRONG SCA IN THESE
ZNS...AND WILL LET MIDNGT SHIFT DECIDE WHETHER TO UPGRADE TO A GALE
WARNG BASED ON NEWER GUIDANCE. BASED ON 12Z/22 GUIDANCE...COLD
ADVECTION REMAINS DELAYED BEHIND FRONT...WHICH WAS PUSHING OFF THE
CST LATE THIS AFTN. THIS MEANS NORTHERLY WIND SURGE WON`T BEGIN
UNTIL LATE TNGT/EARLY MON MORNG. SURGE WILL CONTINUE THRU
MON...BEFORE WINDS DIMINISH MON NGT. SEAS WILL BLD TO 5-9 FT AND
WAVES WILL BLD TO 3-5 FT IN THE CHES BAY. HI PRES BLDS ACRS THE
REGION MON NGT/TUE...THEN MOVES OFFSHR TUE AFTN/TUE NGT...AHEAD OF
NEXT ARCTIC FRONT. THIS FRONT WILL CROSS THE AREA ON WED...FOLLOWED
BY ANOTHER SURGE OF COLD AIR FOR THU AND FRI.
&&
.TIDES/COASTAL FLOODING...
LOW WATER ADVISORIES HAVE ENDED AS THE NEGATIVE ANOMALIES HAVE
DIMINISHED...BUT WATER LEVELS GENLY REMAIN BELOW ASTRONOMICAL
TIDES THROUGH MIDWEEK.
&&
.CLIMATE...
NORFOLK`S LOW TEMPERATURE OF 9 DEGREES ON FEB 20 WAS THE COLDEST
FOR SO LATE IN THE SEASON. THE MINUS 4 DEGREE READING AT SALISBURY
ON FEB 21ST IS NOW THE ALL TIME LOW FOR THE MONTH OF FEBRUARY.
THE CURRENT AVERAGE TEMPERATURES FOR THE MONTH OF FEBRUARY AT
BOTH RICHMOND AND NORFOLK PLACE THEM IN THE TOP 10 COLDEST. WITH
ADDITIONAL COLD TEMPERATURES EXPECTED NEXT WEEK...IT IS VERY
LIKELY THAT BOTH SITES WILL HAVE AVERAGE TEMPERATURES IN THE TOP
10 COLDEST FEBRUARYS ON RECORD...PERHAPS IN THE TOP 5 COLDEST.
RECORD LOW TEMPERATURES FOR TUESDAY 2/24:
RIC...11 IN 1914
ORF...16 IN 1947
SBY...10 IN 1934
ECG...19 IN 1947
&&
.AKQ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
NC...NONE.
VA...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 7 PM EST THIS EVENING FOR
ANZ635>638.
DENSE FOG ADVISORY UNTIL 4 AM EST EARLY THIS MORNING FOR
ANZ631-632-634-638-650-652-654-656.
SMALL CRAFT ADVISORY UNTIL MIDNIGHT EST TONIGHT FOR ANZ630>634-
650-652-654.
SMALL CRAFT ADVISORY UNTIL 6 AM EST TUESDAY FOR ANZ656-658.
&&
$$
SYNOPSIS...ALB/MPR
NEAR TERM...ALB/MPR
SHORT TERM...MPR
LONG TERM...LSA
AVIATION...LKB
MARINE...LSA
TIDES/COASTAL FLOODING...AKQ
CLIMATE...AKQ
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
135 AM EST MON FEB 23 2015
.SYNOPSIS...
A COLD AND DRY AIR MASS SETTLES IN TO START THE WEEK. ANOTHER COLD
FRONT SWINGS THROUGH THE REGION TUESDAY NIGHT.
&&
.NEAR TERM /THROUGH TODAY/...
CURRENT MOSAIC RADAR IMAGERY SHOWS LIGHT SNOW CONTINUING TO STREAM
ACROSS THE FORECAST AREA...ASSOCIATED WITH A RELATIVELY DRY COLD
FRONT BI-SECTING THE CWA. BEHIND THE FRONT...PRECIPITATION REGIME
TURNS SHOWERY WITH STRIATIONS OF LIGHT SNOW SHOWERS STRETCHING
FROM THE SOUTHERN SHORE OF LAKE ERIE INTO OUR FAR ERN OHIO
COUNTIES. THE LATEST RAP HAS A GOOD HANDLE ON BOTH THE TIMING OF
THE SNOW ALONG THE FRONT AND THE LOCATION/TIMING ON THE SHOWERS
BEHIND IT. CONTINUED TO FOLLOW THE RAP THROUGH THE EARLY MORNING
AS THE MID AND UPPER LEVEL MOISTURE OVERRUNS THE LOW LEVEL
MOISTURE AND THE SNOW CEASES.
TEMPERATURES WILL CONTINUE TO FALL THROUGH THE EARLY
MORNING...BOTTOMING OUT BELOW ZERO NORTH OF I-80...AND THE SINGLE
DIGITS ABOVE ZERO FOR MOST OTHER LOCATIONS. AS THE COLD FRONT
CROSSES...A SUBTLE WIND SHIFT IS NOTED...BUT AN INCREASE IN FLOW
SPEED IS THE BIGGER IMPACT. ALREADY SEEING WIND CHILLS INTO THE
SINGLE DIGITS. SHOULD SEE WIND CHILL VALUES BELOW -10 IN THE NEXT
FEW HOURS LEADING TO YET ANOTHER FRIGID MORNING.
OPTIMISTICALLY CUTTING BACK ON CLOUDS THIS MORNING AND THROUGH THE
BALANCE OF MONDAY. BEHIND THE EXITING FRONT...COPIOUS DRY AIR WILL
CLEAR THE COLUMN. ALL UPSTREAM OBSERVATIONS SHOW CLEAR SKIES AND
WITH LAKE ERIE COMPLETELY FROZEN...NO DOWNSTREAM LAKE-INDUCED CLOUDS
ARE EXPECTED. A DECEPTIVELY SUNNY DAY IS EXPECTED AS TEMPERATURES
WILL REMAIN WELL BELOW AVERAGE. BUMPED HIGHS UP A FEW DEGREES AS
THE INCREASINGLY POTENT LATE FEBRUARY SUNSHINE SHOULD MAKE INROADS
ON THIS LATEST ARCTIC AIRMASS.
TAX
&&
.SHORT TERM /TONIGHT THROUGH 6 PM TUESDAY/...
TEMPERATURES WILL PLUMMET BEHIND THE FRONTAL BOUNDARY WITH MORNING
LOWS PROJECTED AROUND ZERO...ON AVERAGE...ACROSS THE REGION.
CHANGES TO THE PREVIOUS TEMPERATURE FORECAST WERE MINIMAL...BUT
TWEAKS WERE BASED PRIMARILY ON CANADIAN AND ADJUSTED MET GUIDANCE
WHICH HAS PERFORMED WELL AS OF LATE.
PROGGED SURFACE GRADIENTS STILL LOOK SUPPORTIVE OF WIND THAT
WOULD RESULT IN A WIND CHILLS DROPPING BELOW THE -10F THRESHOLD
ACROSS MUCH OF THE REGION BY EARLY MONDAY MORNING. THE WIND CHILL
ADVISORY HAS THUS BEEN EXPANDED TO INCLUDE ALL BUT A FEW COUNTIES
TO THE SOUTH OF INTERSTATE 70...AND HAS BEEN SEGMENTED FOR WIND
CHILL MAGNITUDE AND TIMING.
THE COLD WEATHER WILL CONTINUE INTO MONDAY NIGHT...BUT BUILDING
HIGH PRESSURE IS EXPECTED TO SLACKEN THE WIND AND PRECLUDE A
CONTINUATION OF THE WIND CHILL ADVISORY AS MONDAY EVENING FALLS.
&&
.LONG TERM /TUESDAY NIGHT THROUGH SUNDAY/...
AN UPPER TROUGH OVER THE NORTHEASTERN CONUS...AND ITS ASSOCIATED
SURFACE COLD FRONT...IS PROGGED FOR A LATE TUESDAY NIGHT/EARLY
WEDNESDAY PASSAGE. BEST MOISTURE AND UPPER SUPPORT SHOULD REMAIN
NORTH OF THE AREA SO MAINTAINED ONLY CHANCE POPS FOR SNOW SHOWERS.
A DEAMPLIFIED UPPER PATTERN IS PROGGED TO SET UP FOR THE REMAINDER
OF THE PERIOD WITH MAINLY DRY WEATHER UNTIL THE APPROACH AND
PASSAGE OF A WEEKEND TROUGH.
AFTER A COLD START TEMPERATURES SHOULD BEGIN TO MODERATE BY THE
WEEKEND. WPC GUIDANCE DEPICTED A MODEL BLEND SOLUTION SMOOTHING
OUT MODEL DIFFERENCES...AND WAS USED WITH A FEW TWEAKS.
&&
.AVIATION /06Z MONDAY THROUGH FRIDAY/...
SLOWED THE EXODUS OF THE ARCTIC FRONT AND ASSOCIATED MVFR SNOW/CLOUDS
THIS MORNING BY A FEW HOURS...BUT GENERALLY EXPECTING IMPROVEMENT
TO VFR BY 12Z. CLOUD COVER SHOULD SCATTER OUT THROUGH MIDDAY WITH
TERMINALS ACROSS THE SOUTH SLOWEST TO LOSE THE COVER. WINDS WILL
STAY FROM THE NORTH...AND SLOWLY GRADUALLY DISSIPATE THROUGH THE
AFTERNOON/EVENING. GENERALLY CLEAR CONDITIONS ARE EXPECTED TONIGHT.
TAX
OUTLOOK.../MONDAY NIGHT THROUGH FRIDAY/...
RESTRICTIONS ARE POSSIBLE WITH A TUESDAY NIGHT/WEDNESDAY COLD
FRONT.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...WIND CHILL ADVISORY FROM 6 AM THIS MORNING TO 7 PM EST THIS
EVENING FOR MDZ001.
OH...WIND CHILL ADVISORY FROM 4 AM EARLY THIS MORNING TO 1 PM EST
THIS AFTERNOON FOR OHZ039>041-048>050-057>059.
PA...WIND CHILL ADVISORY FROM 4 AM EARLY THIS MORNING TO 1 PM EST
THIS AFTERNOON FOR PAZ020-021-029-073-075.
WIND CHILL ADVISORY UNTIL 7 PM EST THIS EVENING FOR PAZ007>009-
013>016-022-023.
WIND CHILL ADVISORY FROM 6 AM THIS MORNING TO 7 PM EST THIS
EVENING FOR PAZ074-076.
WV...WIND CHILL ADVISORY FROM 4 AM EARLY THIS MORNING TO 1 PM EST
THIS AFTERNOON FOR WVZ001>003.
WIND CHILL ADVISORY FROM 6 AM THIS MORNING TO 7 PM EST THIS
EVENING FOR WVZ023-041.
&&
$$
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
250 AM EST MON FEB 23 2015
.SHORT TERM...(THIS EVENING THROUGH MONDAY)
ISSUED AT 305 PM EST SUN FEB 22 2015
A VERY COLD UPPER TROUGH IS SLIDING EAST ACROSS THE UPPER GREAT
LAKES REGION THIS AFTERNOON...WITH RAP ANALYZED 850MB TEMPS OF -29C
OVER WESTERN LAKE SUPERIOR. THIS HAS LED TO AFTERNOON TEMPERATURES
AROUND 25-30 DEGREES BELOW THE NORMAL HIGHS FOR THIS TIME OF YEAR
WITH 2PM TEMPERATURES RANGING FROM -10 AT KCMX TO 7 AT KMNM. THE
COLD AIR AND A FEW BREAKS IN THE ICE...OR AT LEAST AREAS OF THIN
ICE...HAS CONTINUED TO LEAD TO VERY THIN BANDS OF LAKE EFFECT OFF
LAKE SUPERIOR IN THE NORTHWEST WIND SNOW BELTS. WHILE THE BANDS HAVE
BEEN THIN...OBS AND WEBCAMS HAVE SHOWN THAT THEY CONTINUE TO BE
EFFICIENT AT REDUCING VISIBILITIES WITH ALL OF THE CLOUDY WELL BELOW
THE DGZ. THOSE VERY LOCALIZED LOWER VISIBILITIES HAVE ALSO BEEN
AIDED BY BLOWING SNOW FROM THE GUSTY NORTHWEST WINDS OF 15-30MPH.
MEANWHILE...A SURFACE HIGH IS CURRENTLY LOCATED OVER THE EASTERN
DAKOTAS AND AN ASSOCIATED SURFACE RIDGE IS NOSING INTO THE UPPER
GREAT LAKES.
THE HIGH WILL DROP SOUTHEAST INTO THE MID MISSISSIPPI VALLEY
TONIGHT...WHICH WILL PUSH A RIDGE ACROSS THE UPPER GREAT LAKES
REGION. THIS RIDGE WILL LEAD TO BACKING WINDS THROUGH THE
NIGHT...BECOMING SOUTHWESTERLY LATE TONIGHT OVER THE WEST AND MONDAY
MORNING OVER THE EAST. THESE BACKING WINDS...ALONG WITH INCREASING
SUBSIDENCE...WILL DIMINISH THE LAKE EFFECT POTENTIAL FROM THE
LIMITED HEATING FROM LAKE SUPERIOR. THUS...EXPECT SKIES TO BECOME
MOSTLY CLEAR THIS EVENING OVER MUCH OF THE AREA AS THE DIURNAL CU
DISSIPATE...WITH THE EASTERN U.P. HANGING ON THE LONGEST INTO THE
OVERNIGHT HOURS. WHILE THE CLEAR SKIES WILL PROMOTE RADIATIONAL
COOLING...THINKING THERE WILL BE ENOUGH MIXING FROM JUST ABOVE THE
SURFACE AND THE REMAINING PRESSURE GRADIENT TO KEEP LOWS FROM
GETTING AS COLD AS SEEN A FEW DAYS AGO ON THE CLEAR/CALM NIGHTS. BUT
WITH THE COLD AIR IN PLACE AND LITTLE REBOUND IN TEMPS TODAY...HAVE
LOWS IN THE TEENS AND TWENTIES BELOW ZERO FOR TONIGHT. WHEN COMBINED
WITH THE EXPECTED WINDS OF 4-8MPH TONIGHT...WIND CHILL VALUES WILL
REMAIN IN THE -25 TO -35 DEGREE RANGE THROUGH MONDAY MORNING. DO
HAVE A FEW AREAS WHERE WIND CHILLS WILL BE IN WARNING CRITERIA
(GENERALLY OVER IRON COUNTY)...BUT WITH WINDS IN THOSE AREAS ONLY
AROUND 5MPH OVERNIGHT...DIDN/T FEEL THAT THE WINDS WERE CLOSE ENOUGH
TO OUR 10MPH CRITERIA TO ISSUE THE WARNING. ALSO AM A LITTLE
CONCERNED WITH WIND CHILLS REACHING WARNING CRITERIA OVER THE
KEWEENAW PENINSULA...AS THEY HAVE BEEN BOUNCING BACK AND FORTH OVER
THE -35 CRITERIA LATE THIS MORNING AND INTO THE AFTERNOON. THIS WILL
LIKELY CONTINUE THROUGH MUCH OF THE NIGHT AS WINDS BACK AND THE
TIGHTEST GRADIENT PIVOTS OVER THAT AREA. EITHER WAY...IT WILL BE
VERY COLD ACROSS UPPER MICHIGAN TONIGHT INTO MONDAY MORNING.
OVERALL...MONDAY LOOKS TO BE QUIET ACROSS THE AREA AS THE HIGH
PRESSURE RIDGE DEPARTS. AFTER A SUNNY START TO THE DAY...MID-HIGH
CLOUDS WILL STREAM OVER THE AREA THROUGH THE AFTERNOON AHEAD OF A
COLD FRONT THAT WILL MOVE THROUGH THE AREA LATE MONDAY NIGHT. BUT
WITH ABUNDANT DRY AIR BETWEEN 900-700MB...EXPECT THE PRECIPITATION
TO STAY OFF TO THE WEST OF UPPER MICHIGAN THROUGH THE LATE
AFTERNOON. WINDS WILL GET GUSTY OUT OF THE SOUTHWEST DURING THE
AFTERNOON AND ESPECIALLY THE EVENING. THUS...ADDED PATCHY BLOWING
SNOW TO SOME AREAS OVER THE WEST DURING THE LATE AFTERNOON. WILL SEE
HIGHS REBOUND INTO THE SINGLE DIGITS AND A FEW LOWER TEENS ABOVE
ZERO TOMORROW...BUT WITH THE INCREASING WINDS IN THE AFTERNOON IT
WILL STILL FEEL VERY COLD.
.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 250 AM EST MON FEB 23 2015
TUESDAY THROUGH SUNDAY WILL BE MARKED BY BOOKEND LOW PRESSURE
SYSTEMS...WITH HIGH PRESSURE IN BETWEEN. THE FIRST AT 12Z TUESDAY
WILL BE SET UP FROM S HUDSON BAY THROUGH CENTRAL ONTARIO...AND
CENTRAL LAKE SUPERIOR...DRAGGING A COLD FRONT ACROSS THE W THIRD OF
THE CWA. THE FRONTAL BOUNDARY WILL SWIFTLY EXIT E...AND RESIDE FROM
JAMES BAY THRUOGH FAR SE LAKE SUPERIOR BY 18Z TUESDAY. 1-2 IN OF NEW
SNOW WILL BE POSSIBLE TUESDAY OVER MUCH OF THE CWA...WITH THE
HIGHEST VALUES FAR N AND E. WHILE WINDS ALOFT WILL BE DIMINISHING
FROM THE 40-50KT WINDS OVERNIGHT...SFC WINDS WILL BE STEADY TO ON
THE INCREASE. LOOK FOR WINDS OF 10-20KTS DURING THE DAY
TUESDAY...HIGHEST W AND ALONG LAKE SUPERIOR.
WILL BE INTERESTING TO SEE WHAT THE INCREASED SW WINDS TODAY-
TONIGHT...AND NW WINDS TUESDAY DO TO THE RELATIVLY THIN AND
FRACTURED ICE COVERING MUCH OF LAKE SUPERIOR. HOW IT PROGRESSES WILL
HAVE A LARGE IMPACT ON THE AREAL COVERAGE AND INTENSITY OF LAKE
EFFECT SNOW BANDS TUESDAY AFTERNOON THROUGH THURSDAY ON MAINLY NW TO
WNW WINDS.
SLOWLY FALLING INVERSION HEIGHTS TUESDAY NIGHT...AND THE DGZ GOING
AWAY AS MUCH COLDER AIR SLIDES IN ON THE NW WINDS WILL RESULT IN THE
RETURN OF SMALL SNOWFLAKES THAT WILL NOT ACCUMULATE TO MUCH BUT ARE
VERY AFFECTIVE AT REDUCING VIS. ANOTHER COLD ARCTIC ARIMASS WILL BE
ABLE TO SLIDE INTO THE REGION AS HIGH PRESSURE OVER MUCH OF THE W
HALF OF CANADA SLOWLY SINKS ACROSS S CENTRAL CANADA...THE N AND
CENTRAL PLAINS...AND THE UPPER GREAT LAKES BY THE END OF THE WORK
WEEK. LIGHT LES ON N TO WNW WINDS WILL BE THE RULE.
WIND CHILL VALUES WILL AGAIN FALL INTO THE -20 TO -30F RANGE LATE
TUESDAY NIGHT THROUGH WEDNESDAY MORNING. THAT 10MPH WIND PORTION OF
THE WIND CHILL ADVISORY SHOULD BE MET ACROSS MOST OF THE CWA...WITH
STRONGER NW WINDS NEARING 15MPH N CENTRAL AND E ALONG LAKE SUPERIOR.
THE APPARENT TEMPERATURE PORTION OF WIND CHILL ADVISORY CRITERIA IS
-25 TO -34F.
LATE WEDNESDAY NIGHT INTO EARLY THURSDAY MORNING MAY AGAIN BRING US
DOWN TO 20 TO NEAR 30 BELOW ZERO WIND CHILLS. HOWEVER...THE NW WINDS
SHOULD BE MUCH LIGHTER.
THURSDAY NIGHT-FRIDAY WILL BE A PERIOD OF MAINLY W TO WSW WINDS.
LAKE EFFECT SNOW SHOWERS SHOULD BE EITHER MIMIMAL OR NON-
EXISTANT...AND IMPACTING THE KEWEENAW PENINSULA AND RIGHT ALONG THE
LAKE SUPERIOR SHORELINE AROUND AND E OF GRAND MARAIS.
EXPECT DRY WEATHER SATURDAY...BUT INCREASING SW WINDS AND INVADING
CLOUDS FROM THE W. 850MB TEMPS WILL RISE TO AROUND -11 TO -13C
SATURDAY AND SUNDAY. SFC TEMPERATURES SHOULD REBOUND TO NEAR
20F...WHICH IS STILL AROUND 10 DEGREES BELOW NORMAL FOR THIS TIME OF
YEAR. SUNDAY SHOULD BE A COUPLE DEGREES WARMER...BUT FILLED WITH
MORE CLOUDS AND SNOW FOR THE ENTIRE CWA. EARLY INDICATIONS FROM THE
GFS POINT TO 2-5IN OF SNOW CWA WIDE LATE SATURDAY AFTERNOON THROUGH
SUNDAY EVENING. THE BEST MOISTURE LOOKS TO REMAIN TO OUR S AS UPPER
MI IS IN BETWEEN 2 LOWS /ONE OVER HUDSON BAY...AND ANOTHER EJECTING
OUT OF THE CENTRAL PLAINS/.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT)
ISSUED AT 1220 AM EST MON FEB 23 2015
A STEADY WNW SLOWLY BACKING SW FLOW OF DRY AIR TO THE N OF HI PRES
MOVING INTO THE OH RIVER VALLEY WL RESULT IN VFR CONDITIONS AT ALL 3
TAF SITES INTO THIS EVNG. ALTHOUGH THE W WIND WL UPSLOPE INTO CMX
EARLY THIS MRNG...THE UPSTREAM AIRMASS IS SO DRY AND LK SUP
SUFFICIENTLY ICE COVERED TO LIMIT THE POTENTIAL FOR LES OR EVEN MUCH
IN THE WAY OF LK CLDS. THE SW WINDS WL STRENGTHEN AND TURN GUSTY
THIS AFTN AS THE PRES GRADIENT TIGHTENS AHEAD OF A COLD FNT APRCHG
FM THE NW. SN IN ADVANCE OF THIS FNT WL ARRIVE NW-SE LATE THIS EVNG.
DRY NATURE OF THE ANTECEDENT AIRMASS WL MAINTAIN VFR CONDITIONS
INITIALLY DESPITE THE THICKENING CLD COVER AND ARRIVING -SN. BEST
CHC FOR MVFR CONDITIONS BEFORE 24/06Z WL BE AT CMX...WHERE THE PCPN
WL ARRIVE EARLIEST.
&&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 305 PM EST SUN FEB 22 2015
HIGH PRESSURE IN THE DAKOTAS WILL MOVES INTO THE MID MISSISSIPPI
VALLEY LATE TONIGHT AND MONDAY MORNING...WHILE SHIFTING A RIDGE
ACROSS THE UPPER GREAT LAKES REGION. THIS WILL LEAD TO WEAKENING
WINDS TONIGHT...BEFORE QUICKLY INCREASING OUT OF THE SOUTHWEST ON
MONDAY AFTERNOON AHEAD OF A LOW PRESSURE SYSTEM DROPPING SOUTHEAST
THROUGH NORTHERN ONTARIO. THIS WILL LEAD TO SOUTHWESTERLY GALES OF
35-40KTS OVER PORTIONS OF LAKE SUPERIOR MONDAY AFTERNOON/EVENING
AND HAVE ISSUED A GALE WARNING FOR MUCH OF WESTERN/CENTRAL LAKE
SUPERIOR FOR LATE MONDAY AFTERNOON AND MONDAY NIGHT. THEN AS A COLD
FRONT SLIDES SOUTHEAST ACROSS LAKE SUPERIOR LATE MONDAY NIGHT INTO
TUESDAY MORNING AND SHIFT WINDS TO THE NORTHWEST. THERE MAY BE A FEW
GALE FORCE GUSTS TO 35 KNOTS BEHIND THE FRONT ON TUESDAY OVER
EASTERN LAKE SUPERIOR. A HIGH PRESSURE RIDGE WILL BUILD BACK INTO
THE AREA WEDNESDAY AND REMAIN INTO FRIDAY...LEADING TO GENERALLY
LIGHT WINDS BELOW 20KTS.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
WIND CHILL ADVISORY UNTIL NOON EST /11 AM CST/ TODAY FOR
MIZ001>007-009>014-084-085.
LAKE SUPERIOR...
GALE WARNING FROM 7 PM THIS EVENING TO 7 AM EST TUESDAY FOR
LSZ266.
GALE WARNING FROM 4 PM EST /3 PM CST/ THIS AFTERNOON TO 7 AM EST
/6 AM CST/ TUESDAY FOR LSZ162-263-264.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...SRF
LONG TERM...KF
AVIATION...KC
MARINE...SRF
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
1221 AM EST MON FEB 23 2015
.SHORT TERM...(THIS EVENING THROUGH MONDAY)
ISSUED AT 305 PM EST SUN FEB 22 2015
A VERY COLD UPPER TROUGH IS SLIDING EAST ACROSS THE UPPER GREAT
LAKES REGION THIS AFTERNOON...WITH RAP ANALYZED 850MB TEMPS OF -29C
OVER WESTERN LAKE SUPERIOR. THIS HAS LED TO AFTERNOON TEMPERATURES
AROUND 25-30 DEGREES BELOW THE NORMAL HIGHS FOR THIS TIME OF YEAR
WITH 2PM TEMPERATURES RANGING FROM -10 AT KCMX TO 7 AT KMNM. THE
COLD AIR AND A FEW BREAKS IN THE ICE...OR AT LEAST AREAS OF THIN
ICE...HAS CONTINUED TO LEAD TO VERY THIN BANDS OF LAKE EFFECT OFF
LAKE SUPERIOR IN THE NORTHWEST WIND SNOW BELTS. WHILE THE BANDS HAVE
BEEN THIN...OBS AND WEBCAMS HAVE SHOWN THAT THEY CONTINUE TO BE
EFFICIENT AT REDUCING VISIBILITIES WITH ALL OF THE CLOUDY WELL BELOW
THE DGZ. THOSE VERY LOCALIZED LOWER VISIBILITIES HAVE ALSO BEEN
AIDED BY BLOWING SNOW FROM THE GUSTY NORTHWEST WINDS OF 15-30MPH.
MEANWHILE...A SURFACE HIGH IS CURRENTLY LOCATED OVER THE EASTERN
DAKOTAS AND AN ASSOCIATED SURFACE RIDGE IS NOSING INTO THE UPPER
GREAT LAKES.
THE HIGH WILL DROP SOUTHEAST INTO THE MID MISSISSIPPI VALLEY
TONIGHT...WHICH WILL PUSH A RIDGE ACROSS THE UPPER GREAT LAKES
REGION. THIS RIDGE WILL LEAD TO BACKING WINDS THROUGH THE
NIGHT...BECOMING SOUTHWESTERLY LATE TONIGHT OVER THE WEST AND MONDAY
MORNING OVER THE EAST. THESE BACKING WINDS...ALONG WITH INCREASING
SUBSIDENCE...WILL DIMINISH THE LAKE EFFECT POTENTIAL FROM THE
LIMITED HEATING FROM LAKE SUPERIOR. THUS...EXPECT SKIES TO BECOME
MOSTLY CLEAR THIS EVENING OVER MUCH OF THE AREA AS THE DIURNAL CU
DISSIPATE...WITH THE EASTERN U.P. HANGING ON THE LONGEST INTO THE
OVERNIGHT HOURS. WHILE THE CLEAR SKIES WILL PROMOTE RADIATIONAL
COOLING...THINKING THERE WILL BE ENOUGH MIXING FROM JUST ABOVE THE
SURFACE AND THE REMAINING PRESSURE GRADIENT TO KEEP LOWS FROM
GETTING AS COLD AS SEEN A FEW DAYS AGO ON THE CLEAR/CALM NIGHTS. BUT
WITH THE COLD AIR IN PLACE AND LITTLE REBOUND IN TEMPS TODAY...HAVE
LOWS IN THE TEENS AND TWENTIES BELOW ZERO FOR TONIGHT. WHEN COMBINED
WITH THE EXPECTED WINDS OF 4-8MPH TONIGHT...WIND CHILL VALUES WILL
REMAIN IN THE -25 TO -35 DEGREE RANGE THROUGH MONDAY MORNING. DO
HAVE A FEW AREAS WHERE WIND CHILLS WILL BE IN WARNING CRITERIA
(GENERALLY OVER IRON COUNTY)...BUT WITH WINDS IN THOSE AREAS ONLY
AROUND 5MPH OVERNIGHT...DIDN/T FEEL THAT THE WINDS WERE CLOSE ENOUGH
TO OUR 10MPH CRITERIA TO ISSUE THE WARNING. ALSO AM A LITTLE
CONCERNED WITH WIND CHILLS REACHING WARNING CRITERIA OVER THE
KEWEENAW PENINSULA...AS THEY HAVE BEEN BOUNCING BACK AND FORTH OVER
THE -35 CRITERIA LATE THIS MORNING AND INTO THE AFTERNOON. THIS WILL
LIKELY CONTINUE THROUGH MUCH OF THE NIGHT AS WINDS BACK AND THE
TIGHTEST GRADIENT PIVOTS OVER THAT AREA. EITHER WAY...IT WILL BE
VERY COLD ACROSS UPPER MICHIGAN TONIGHT INTO MONDAY MORNING.
OVERALL...MONDAY LOOKS TO BE QUIET ACROSS THE AREA AS THE HIGH
PRESSURE RIDGE DEPARTS. AFTER A SUNNY START TO THE DAY...MID-HIGH
CLOUDS WILL STREAM OVER THE AREA THROUGH THE AFTERNOON AHEAD OF A
COLD FRONT THAT WILL MOVE THROUGH THE AREA LATE MONDAY NIGHT. BUT
WITH ABUNDANT DRY AIR BETWEEN 900-700MB...EXPECT THE PRECIPITATION
TO STAY OFF TO THE WEST OF UPPER MICHIGAN THROUGH THE LATE
AFTERNOON. WINDS WILL GET GUSTY OUT OF THE SOUTHWEST DURING THE
AFTERNOON AND ESPECIALLY THE EVENING. THUS...ADDED PATCHY BLOWING
SNOW TO SOME AREAS OVER THE WEST DURING THE LATE AFTERNOON. WILL SEE
HIGHS REBOUND INTO THE SINGLE DIGITS AND A FEW LOWER TEENS ABOVE
ZERO TOMORROW...BUT WITH THE INCREASING WINDS IN THE AFTERNOON IT
WILL STILL FEEL VERY COLD.
.LONG TERM...(MONDAY NIGHT THROUGH SUNDAY)
ISSUED AT 356 PM EST SUN FEB 22 2015
PATTERN OF HIGH AMPLITUDE UPR RIDGE OVER THE ERN PACIFIC/WRN
NAMERICA AND DEEP TROF OVER CENTRAL AND ERN NAMERICA WL PERSIST THRU
MUCH OF THE WEEK...RESULTING IN A CONTINUED NW FLOW ALOFT THAT WL
BRING ARCTIC SURGES INTO THE UPPER LKS THRU MID WEEK. TOWARD THE END
OF THE WEEK THOUGH...FALLING HGTS OVER THE W WL ALLOW FOR A MORE
ZONAL FLOW AND SOME AIRMASS MODERATION. BUT WITH DRY HI PRES FCST TO
BE DOMINATING...LOW TEMPS MAY STILL BE QUITE COLD DESPITE THE MORE
SEASONABLE H85 AND DAYTIME TEMPS.
MON NGT/TUE...SHRTWV AND ACCOMPANYING SFC LOW DESCENDING SE INTO FAR
NW ONTARIO BY MON EVNG ARE FCST TO SLIDE JUST NE OF LK SUP DURING
THIS TIME...WITH ATTENDANT COLD FROPA MOVING OVER UPR MI LATE MON
NIGHT AND TUE MRNG. SOME LIGHT SN IN THE WAA/ISENTROPIC ASCENT
PATTERN AHEAD OF THIS DISTURBANCE WL OVERSPREAD UPR MI FM THE NW ON
MON NGT AND PERSIST INTO TUE MRNG BEFORE THE COLD FROPA. SINCE THE
MSTR INFLOW WL BE RATHER UNIMPRESSIVE...WITH MIXING RATIOS OF 1-1.5
G/KG FCST ON 280K ISENTROPIC SFC...AND VERY DRY ANTECEDENT AIRMASS
IN PLACE WHICH WL TAKE TIME TO MOISTEN...ACCOMPANYING SN ACCUMS
SHOULD BE LIMITED TO NO MORE THAN 1 TO 2 INCHES FOR MOST OF CWA WITH
MAYBE A FEW LOCATIONS SEEING 3-4 INCHES FAR EAST AND OVER TIP OF
KEWEENAW...WHERE HIGHER POPS/QPF WL BE MAINTAINED CLOSER TO THE
SHRTWV TRACK...LONGER DURATION OF ISENTROPIC ASCENT AND AREA OF
STRONGER DEEP LAYER Q-VECT CONV. ALTHOUGH MODELS SNDGS INDICATE THE
DGZ TO BE RATHER DEEP AND INTERSECTING MUCH OF THE ASSOCIATED
UVV...STRONG WINDS THROUGH THE MUCH OF THE LAYER MIGHT BREAK UP THE
DENDRITES TO A CERTAIN EXTENT. BUT AT SAME TIME...THE SMALLER FLAKES
WOULD BE MORE EFFICIENT AT RESTRICTING VSBY WHILE BEING BLOWN ABOUT
BY THE GUSTY VEERING WINDS OCCURRING UNDER THE TIGHT PRES GRADIENT
AHEAD OF THE COLD FRONT. WITH H85 THERMAL RDG OVER UPR MI ON MON NGT
AND THE GUSTY WINDS...EXPECT RELATIVELY HIGH MIN TEMPS. WSHFT TO THE
NW FOLLOWING THE TUE MORNING COLD FROPA WL DRAG ANOTHER ARCTIC
AIRMASS BACK INTO THE CWA IN THE AFTN...DROPPING H85 TEMPS TO -20C
OR COLDER AGAIN BY 00Z WED AND ALLOWING FOR AT LEAST SCATTERED LES
TO DEVELOP IN WHATEVER BREAKS THERE ARE IN LAKE SUPERIOR ICE COVER.
TUE NGT INTO WED NIGHT...MEDIUM RANGE GUIDANCE FCSTS H85 TEMPS TO
FALL AS LO AS -28C TO -30C AROUND 12Z WED IN COLD NNW FLOW AHEAD OF
THE NEXT CANADIAN HIGH PRES BUILDING TOWARD THE NRN PLAINS. THERE
MAY BE SOME LES OFF BREAKS IN THE EXTENSIVE ICE COVER...BUT THE
BIGGEST STORY WL BE WIND CHILLS AT LEAST REACHING INTO ADVY CRITERIA
TUE NIGHT INTO WED MORNING AS 950 MB WINDS ARE FCST AOA 30 KTS
DURING THE DESTABILIZING PERIOD OF CAA THAT WL DROP MIN TEMPS BLO
ZERO AGAIN. AFTER HIGHS POSSIBLY STRUGGLING TO REACH ABV ZERO OVER
THE NW CWA ON WED...ANOTHER BITTER COLD NIGHT IS IN STORE FOR WED
NIGHT WITH DOUBLE DIGIT BLO ZERO READINGS LIKELY OVER A GOOD
PORTION OF THE CWA.
THU INTO SUN...THE ARCTIC HI OVER SCENTRAL CANADA ON WED IS FCST TO
DRIFT SLOWLY TO THE ESE REACHING THE NRN PLAINS ON THU...AND THE MID
MS VALLEY AND LOWER GREAT LAKES/OH RIVER VALLEY ON FRI BEFORE
REACHING THE MID-ATLANTIC STATES ON SAT UNDER A PATTERN OF SLOWLY
RISING 5H HGTS IN THE GREAT LAKES DOWNSTREAM OF TROFFING OVER WRN
NAMERICA. THE RESULT WL BE A PERIOD OF MAINLY DRY WX UNDER DOMINANT
SFC HIGH PRES RIDGE. ALTHOUGH THERE MAY BE SOME LES MAINLY E OF
MARQUETTE INTO THU WHILE THE LLVL FLOW IS STILL NW...BACKING WINDS
TOWARD THE W AND THEN SW WL SHIFT ANY REMAINING LES OUT INTO LK SUP
BY LATE THU NIGHT. H85 TEMPS ARE FCST TO MODERATE TO -15C TO -17C BY
FRI/SAT...ALLOWING DAYTIME TEMPS TO WARM NEAR 20F UNDER A GOOD DEAL
OF SUNSHINE. HOWEVER...STILL EXPECT VERY COLD OVERNIGHT TEMPS (BLO
ZERO) AT LEAST THU NIGHT AND FRI NIGHT AS FCST PWAT IS LOWER THAN
.10 INCH UNDER LIGHT WINDS. MORE CLDS AND LIGHT MAY ARRIVE SAT NIGHT
INTO SUN IN ADVANCE OF THE NEXT APPROACHING LOW PRES TROF.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT)
ISSUED AT 1220 AM EST MON FEB 23 2015
A STEADY WNW SLOWLY BACKING SW FLOW OF DRY AIR TO THE N OF HI PRES
MOVING INTO THE OH RIVER VALLEY WL RESULT IN VFR CONDITIONS AT ALL 3
TAF SITES INTO THIS EVNG. ALTHOUGH THE W WIND WL UPSLOPE INTO CMX
EARLY THIS MRNG...THE UPSTREAM AIRMASS IS SO DRY AND LK SUP
SUFFICIENTLY ICE COVERED TO LIMIT THE POTENTIAL FOR LES OR EVEN MUCH
IN THE WAY OF LK CLDS. THE SW WINDS WL STRENGTHEN AND TURN GUSTY
THIS AFTN AS THE PRES GRADIENT TIGHTENS AHEAD OF A COLD FNT APRCHG
FM THE NW. SN IN ADVANCE OF THIS FNT WL ARRIVE NW-SE LATE THIS EVNG.
DRY NATURE OF THE ANTECEDENT AIRMASS WL MAINTAIN VFR CONDITIONS
INITIALLY DESPITE THE THICKENING CLD COVER AND ARRIVING -SN. BEST
CHC FOR MVFR CONDITIONS BEFORE 24/06Z WL BE AT CMX...WHERE THE PCPN
WL ARRIVE EARLIEST.
&&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 305 PM EST SUN FEB 22 2015
HIGH PRESSURE IN THE DAKOTAS WILL MOVES INTO THE MID MISSISSIPPI
VALLEY LATE TONIGHT AND MONDAY MORNING...WHILE SHIFTING A RIDGE
ACROSS THE UPPER GREAT LAKES REGION. THIS WILL LEAD TO WEAKENING
WINDS TONIGHT...BEFORE QUICKLY INCREASING OUT OF THE SOUTHWEST ON
MONDAY AFTERNOON AHEAD OF A LOW PRESSURE SYSTEM DROPPING SOUTHEAST
THROUGH NORTHERN ONTARIO. THIS WILL LEAD TO SOUTHWESTERLY GALES OF
35-40KTS OVER PORTIONS OF LAKE SUPERIOR MONDAY AFTERNOON/EVENING
AND HAVE ISSUED A GALE WARNING FOR MUCH OF WESTERN/CENTRAL LAKE
SUPERIOR FOR LATE MONDAY AFTERNOON AND MONDAY NIGHT. THEN AS A COLD
FRONT SLIDES SOUTHEAST ACROSS LAKE SUPERIOR LATE MONDAY NIGHT INTO
TUESDAY MORNING AND SHIFT WINDS TO THE NORTHWEST. THERE MAY BE A FEW
GALE FORCE GUSTS TO 35 KNOTS BEHIND THE FRONT ON TUESDAY OVER
EASTERN LAKE SUPERIOR. A HIGH PRESSURE RIDGE WILL BUILD BACK INTO
THE AREA WEDNESDAY AND REMAIN INTO FRIDAY...LEADING TO GENERALLY
LIGHT WINDS BELOW 20KTS.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
WIND CHILL ADVISORY UNTIL NOON EST /11 AM CST/ TODAY FOR
MIZ001>007-009>014-084-085.
LAKE SUPERIOR...
GALE WARNING FROM 7 PM THIS EVENING TO 7 AM EST TUESDAY FOR
LSZ266.
GALE WARNING FROM 4 PM EST /3 PM CST/ THIS AFTERNOON TO 7 AM EST
/6 AM CST/ TUESDAY FOR LSZ162-263-264.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...SRF
LONG TERM...VOSS
AVIATION...KC
MARINE...SRF
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
332 AM EST MON FEB 23 2015
.SYNOPSIS...
RAIN ASSOCIATED WITH A COLD FRONTAL PASSAGE OVERNIGHT WILL BE
LIGHT TONIGHT. WEAK LOW PRESSURE WILL MOVE ALONG THE STALLED
FRONT LATER TODAY...SPREADING MORE SIGNIFICANT RAIN NORTHWARD.
COLD AIR WILL RETURN THIS EVENING AS ARCTIC HIGH PRESSURE SNEAKS
BACK ACROSS THE REGION. COLD AND UNSETTLED WEATHER IS EXPECTED
DURING THE UPCOMING WEEK AS CHILLY HIGH PRESSURE AND GULF MOISTURE
INTERACT.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 930 PM SUNDAY...SCATTERED AREAS OF RAIN IS LEADING A FRONTAL
BOUNDARY THAT WILL SLOWLY PUSH OFF THE COAST BY MORNING. THE AREA
OF RAIN IS PRODUCING TOTAL OF LESS THAN A TENTH OF AN INCH. THE
LATEST RUN OF THE HRRR IS SHOWING THE COVERAGE OF THE RAIN
BECOMING MORE WIDESPREAD OVERNIGHT. TEMPERATURES ARE EXPECTED TO
FALL ONLY TO AROUND 40 IN THE NORTHWEST TO THE UPPER 40S SOUTH AND
WEST OF MYRTLE BEACH.
&&
.SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/...
AS OF 3 AM MONDAY...PERIOD BEGINS WITH FRONT STALLED ACROSS THE FL
PENINSULA BUT ITS EXACT LOCATION REMAINS SOMEWHAT IN QUESTION. MOST
OF THE GUIDANCE HAS THIS FRONT STALLED ACROSS CENTRAL OR SOUTHERN FL
WITH ONLY THE NAM KEEPING IT FARTHER NORTH. WEAK SURFACE WAVE WILL
DEVELOP ALONG THE FRONT AND MOVE SLOWLY EAST-NORTHEAST. THIS FEATURE
HELPS SPREAD PRECIP OVER THE AREA TUE INTO TUE NIGHT AS IT PASSES
OFF THE CAROLINA COAST. ISENTROPIC LIFT WILL BE ONGOING TUE IN A
ENVIRONMENT FULL OF LOW LEVEL MOISTURE. THERMAL PROFILES IN MOST OF
THE GUIDANCE SUPPORTS ALL SNOW AT FIRST. SOUTHERN AREAS WILL
TRANSITION TO A WINTRY MIX WHILE NORTHERN LOCATIONS REMAIN IN AN ALL
FROZEN REGIME. AT THIS POINT SOUNDINGS DO NOT SUPPORT SIGNIFICANT
AMOUNTS OF ZR BUT MUCH CAN CHANGE BETWEEN NOW AND THEN. THE BULK OF
THE MOISTURE WILL REMAIN SOUTH AND EAST OF THE AREA WITH INLAND MOST
ZONES LIKELY TO STAY DRY BUT UNDER CLOUDY SKIES.
WED STARTS OFF DRY BUT NEXT SOUTHERN STREAM SYSTEM...WHICH IS MORE
POTENT THAN THE PREVIOUS ONE...WILL BE MOVING ALONG THE GULF COAST.
TRACK OF THE SURFACE FEATURE...ALONG THE REMAINS OF THE STALLED
SURFACE BOUNDARY...WILL BE ACROSS NORTHERN FL WED AND UP THE EAST
COAST WED NIGHT. THE QUESTION IS HOW CLOSE WILL THE LOW PASSES. THE
GFS/NAM/CANADIAN HAVE A WEAKER SHORTWAVE COMPARED TO THE ECMWF AND
THUS A SLIGHTLY LESS AMPLIFIED MID LEVEL PATTERN. THIS KEEPS THE LOW
FARTHER OFF THE COAST WHICH RESULTS IN A LITTLE LESS PRECIP IN THE
AREA. CONTINUE TO FAVOR THIS SOLUTION GIVEN THE NATURE OF THE
PATTERN AND THE LOCATION OF THE BAROCLINIC ZONE. WORTH NOTING THAT
EITHER SOLUTION OPENS UP THE POTENTIAL FOR FROZEN PRECIP LATE WED
NIGHT AS STRONG NORTHERLY FLOW ON THE WEST SIDE OF THE DEEPENING LOW
BRINGS COLDER AIR INTO THE REGION.
&&
.LONG TERM /THURSDAY THROUGH SUNDAY/...
AS OF 3 AM MONDAY...DEEPENING LOW PRESSURE WILL BE PASSING OFF THE
CAROLINA COAST AS THE PERIOD BEGINS WITH PRECIP LIKELY ONGOING
ACROSS THE AREA. THERE IS POTENTIAL FOR FROZEN PRECIP EARLY
THU...BUT UNCERTAINTY REMAINS HIGH. THE FIRST ISSUE TO SORT OUT IS
HOW MUCH PRECIP WILL BE LINGERING ACROSS THE AREA. GFS AND CANADIAN
SOLUTIONS...WHICH PASS THE LOW FARTHER OFF THE COAST INDICATE PRECIP
WILL BE WINDING DOWN AS THE PERIOD BEGINS...THOUGH WITH COLDER AIR
ALREADY FILTERING IN AT THE LOWER LEVELS. THE ECMWF HAS THE LOW
CLOSER TO THE COAST...WHICH KEEPS PRECIP IN THE FORECAST LONGER BUT
BECAUSE IT IS SLOWER IT HAS TEMPS SLIGHTLY WARMER THU MORNING. AS IS
THE CASE WITH THE FASTER SOLUTION COLDER/DRIER LOW LEVEL AIR DOES
WORK ITS WAY IN AS THE PRECIP IS ENDING.
MODELS CONTINUE TO TREND DRIER FOR THE END OF THE WEEK WITH ALL OF
THE MEDIUM RANGE NOW SHOWING A SPRAWLING 1040MB HIGH DROPPING IN
FROM THE UPPER MIDWEST FRI. THE HIGH SHIFTS OVER NEW ENGLAND
SAT...EXPANDING DOWN THE EAST ON SUN BEFORE FINALLY PUSHING EAST
MON. THE AGREEMENT BETWEEN THE GFS/ECMWF/CANADIAN IS ACTUALLY
QUITE SCARY GIVEN THE MIDWEEK NIGHTMARE BUT THE CONTINUED TREND OF
DRYING THE FORECAST DOES INCREASE CONFIDENCE SO HAVE TRENDED LATE
WEEK FORECAST IN THIS DIRECTION. TEMPERATURES BELOW TO WELL BELOW
CLIMO FOR MUCH OF THE PERIOD WILL APPROACH SEASONABLE AS THE
PERIOD ENDS.
&&
.AVIATION /09Z MONDAY THROUGH FRIDAY/...
AS OF 06Z...EXPECT PCPN IN THE FORM OF LIGHT RAIN TO STREAM ACROSS
THE FORECAST AREA BOTH ALONG AND BEHIND THE COLD FRONTAL
BOUNDARY. MOISTURE WILL CONTINUE TO FEED ALONG THE FRONT AS
ASSOCIATED UPPER LEVEL DISTURBANCE RIDES ALONG THE FRONT AND WILL
ENHANCE THE RAINFALL DURING THE PRE-DAWN MON HOURS INTO DAYTIME
MON MORNING. IFR AND POSSIBLY LIFR FROM BOTH CEILINGS AND VSBY
FROM BR AND FG WILL LIKELY DOMINATE ALL TERMINALS THROUGH THE PRE-
DAWN MON HOURS...WITH A SLOW IMPROVEMENT DURING DAYTIME MON
MORNING INTO THE AFTERNOON AS THE FRONT DROPS FURTHER
SOUTH...ENDING THE THREAT FOR PCPN WITH BOTH VSBY AND CEILINGS
IMPROVING. IMMEDIATELY AFTER THE CFP...WINDS WILL VEER TO 360-020
AT 5 TO 10 KT...INCREASING DURING MONDAY TO 10 TO 20 KT...WITH
SOME GUSTS IN THE 20S ESPECIALLY ACROSS THE COASTAL TERMS. THIS IN
RESPONSE TO THE COMBINED EFFORTS OF COLD AIR ADVECTION AND A
TIGHTENED SFC PRESSURE GRADIENT.
EXTENDED OUTLOOK...WAVES OF LOW PRESSURE TO AFFECT THE LOCAL AREA
DURING THE EXTENDED PERIOD...RESULTING WITH POSSIBLE LIFR/IFR/MVFR
CONDITIONS.
&&
.MARINE...
.NEAR TERM /THROUGH TONIGHT/...
AS OF 930 PM SUNDAY...WINDS ARE RELATIVELY LIGHT OVER THE WATERS
WITH SEAS RANGING FROM 2 TO 4 FEET. FRYING PAN SHOALS IS NOW
REPORTING SEAS DOWN TO 5 FEET JUST OUTSIDE THE COASTAL WATERS. A
LIGHT RAIN IS EXPECTED OVERNIGHT AS A COLD FRONT SLOWLY
APPROACHES THE WATERS BY DAYBREAK.
SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/...
AS OF 3 AM MONDAY...STRONG WINDS PRIOR TO THE START OF THE PERIOD
WILL HAVE BUILT SEAS HIGH ENOUGH TO LIKELY REQUIRE SCA INTO AT LEAST
THE FIRST HALF OF TUE MORNING. NORTHERLY FLOW WILL BE WEAKENING TUE
AS SURFACE HIGH TO THE NORTH WEAKENS AND GRADIENT GRADUALLY RELAXES.
LOW PRESSURE WILL PASS SOUTHEAST OF THE WATERS TUE EVENING...BACKING
WINDS FROM NORTHEAST TO WEST-SOUTHWEST. GRADIENT WILL FURTHER WEAKEN
TUE NIGHT AND SPEEDS WILL DROP BELOW 10 KT. PERIOD OF LIGHT OFFSHORE
FLOW WILL BE SHORT LIVED AS NEXT SOUTHERN STREAM SYSTEM BEGINS TO
AFFECT THE GRADIENT WED. NORTHERLY FLOW WILL DEVELOP AS EARLY AS
MIDDAY WED WITH SPEEDS INCREASING WED NIGHT AHEAD OF ADVANCING
LOW...POSSIBLY REQUIRING HEADLINES WED NIGHT.
LONG TERM /THURSDAY THROUGH FRIDAY/...
AS OF 3 AM MONDAY...STRONG NORTHEAST FLOW IN THE WAKE OF EXITING LOW
PRESSURE SYSTEMS MAY REQUIRE SCA HEADLINES FOR MUCH IF NOT ALL OF
THE PERIOD. THE FIRST LOW WILL BE LIFTING NORTHEAST AS THE PERIOD
BEGINS. THE SECOND WILL PASS A BIT FARTHER OFFSHORE FRI MORNING BUT
WILL BE A LITTLE STRONGER. THESE SYSTEMS ALONG WITH A SPRAWLING
1040MB HIGH BUILDING IN FROM THE UPPER MIDWEST WILL MAINTAIN
NORTHEAST FLOW AROUND 20 KT AND KEEP SEAS OVER 6 FT.
&&
.ILM WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
NC...NONE.
MARINE...SMALL CRAFT ADVISORY FROM 8 AM THIS MORNING TO 2 PM EST
TUESDAY FOR AMZ250-252-254-256.
&&
$$
NEAR TERM...DRH
SHORT TERM...III
LONG TERM...III
AVIATION...DCH
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
107 AM EST MON FEB 23 2015
.SYNOPSIS...
A MILD AND MOIST AIR MASS WILL LIE ACROSS THE AREA INTO TONIGHT.
RAIN ASSOCIATED WITH A COLD FRONTAL PASSAGE WILL BE LIGHT
TONIGHT...BUT WEAK LOW PRESSURE WILL MOVE ALONG THE STALLED
FRONT...SPREADING MORE SIGNIFICANT RAIN NORTHWARD ON MONDAY. COLD
AIR WILL RETURN LATE MONDAY AS ARCTIC HIGH PRESSURE SNEAKS BACK
ACROSS THE REGION INTO TUE. COLD AND UNSETTLED WEATHER IS EXPECTED
DURING THE UPCOMING WEEK AS CHILLY HIGH PRESSURE AND GULF MOISTURE
INTERACT.
&&
.NEAR TERM /UNTIL 6 AM THIS MORNING/...
AS OF 930 PM SUNDAY...SCATTERED AREAS OF RAIN IS LEADING A FRONTAL
BOUNDARY THAT WILL SLOWLY PUSH OFF THE COAST BY MORNING. THE AREA
OF RAIN IS PRODUCING TOTAL OF LESS THAN A TENTH OF AN INCH. THE
LATEST RUN OF THE HRRR IS SHOWING THE COVERAGE OF THE RAIN
BECOMING MORE WIDESPREAD OVERNIGHT. TEMPERATURES ARE EXPECTED TO
FALL ONLY TO AROUND 40 IN THE NORTHWEST TO THE UPPER 40S SOUTH AND
WEST OF MYRTLE BEACH.
&&
.SHORT TERM /6 AM THIS MORNING THROUGH TUESDAY NIGHT/...
AS OF 330 PM SUNDAY...WAVE OF LOW PRESSURE RIDING ALONG
LINGERING FRONT MON MORNING WILL MOVE OUT OF AREA MON AFTN AS HIGH
PRESSURE BUILDS DOWN FROM THE NORTHWEST. BEST LIFT WILL RUN FROM
SOUTHWEST TO NORTHEAST ALONG BOUNDARY AS IT SHIFTS FARTHER SOUTH
THROUGH THE DAY. THEREFORE THE GREATEST POPS WILL BE IN THE
MORNING...FAIRLY WIDESPREAD ACROSS MUCH OF THE AREA AND THEN
DIMINISHING THROUGH THE AFTERNOON AS DIGGING MID TO UPPER TROUGH
AND HIGH PRESSURE PUSH FRONT SOUTHWARD. EXPECT A COOL RAIN AS
TEMPS DROP FROM MID 40S IN THE MORNING DOWN TO 30S BY AFTN. LATEST
SOUNDINGS KEEP SATURATED COLUMN ABOVE FREEZING UNTIL MON AFTN INTO
EARLY EVE. ONCE COLUMN GOES BELOW FREEZING IT DRIES OUT...LEAVING
ONLY A THIN SATURATED LAYER BETWEEN 6 TO 7 K FT AFTER 00Z ON NAM
SOUNDING. THEREFORE WILL FOLLOW PREVIOUS FORECAST KEEPING POPS OUT
OF FORECAST ONCE FZN PCP IS POSSIBLE LATE MONDAY.
COASTAL CAROLINAS WILL REMAIN AT THE BASE OF A VERY BROAD UPPER
TROUGH THROUGH REMAINDER OF THE PERIOD AS COOL SFC HIGH EXTENDS
DOWN FROM THE NORTH. FRONT WILL LINGER FROM SW TO NE SOUTH OF
FORECAST AREA WITH COOL AIR LOCKED IN PLACE MON NIGHT THROUGH
TUES. TEMPS MONDAY NIGHT WILL FALL INTO THE 20S IN PLENTY OF CAA.
TEMPS AT H85 DROP FROM AROUND 7 C MON MORNING DOWN TO -3C BY TUES
MORNING. MODELS CONTINUE TO SHOW A PERTURBATION MOVING ACROSS THE
CAROLINAS WITH ANOTHER WAVE OF LOW PRESSURE RIDING ALONG THE
FRONT OVERNIGHT MONDAY INTO TUES AS THE FRONT STARTS LIFTING NORTH.
NAM IS MOST AGGRESSIVE IN BRINGING MOISTURE AND LIFT NORTH EARLY
IN THE DAY ON TUES. FOR NOW HAVE INCLUDED SLIGHT CHC UP THROUGH
PORTIONS OF FLORENCE ACROSS TO THE GRAND STRAND AND SOUTH
INITIALLY AND SPREAD NORTH REMAINING ALIGNED MORE ALONG THE COAST
LATER ON TUES. HAVE INCLUDED SOME MIXED PCP AS SOUNDINGS REMAIN
BELOW ZERO UP THROUGH THE COLUMN MON NIGHT INTO EARLY TUES WITH A
WARM NOSE DEVELOPING INTO THE DAY BUT COLD TEMPS HOLDING ON. AS
FRONT TRIES TO MOVE NORTH EXPECT PCP TO SPREAD FARTHER NORTH ON
TUES. SHOULD GET PUSHED SOUTH AND EAST AS ANOTHER FRONT MOVES IN
FROM THE WEST BY WED MORNING. TEMPS SHOULD REMAIN COOL THROUGH THE
PERIOD.
&&
.LONG TERM /WEDNESDAY THROUGH SUNDAY/...
AS OF 300 PM SUNDAY...LARGE...BUT NOT EXCEPTIONALLY DEEP...TROUGH
WILL PERSIST ACROSS THE EAST INTO THE UPCOMING WEEKEND MAINTAIN
COLD AND UNSETTLED CONDITIONS FOR MUCH OF THE EXTENDED.
COLD FRONT STALLED WELL SOUTH OF THE AREA WILL SERVE AS THE
BAROCLINIC GRADIENT ALONG WHICH AN ACTIVE SOUTHERN STREAM WILL SPAWN
SEVERAL WAVES OF LOW PRESSURE. WHILE NONE OF THESE WILL BE
IMPRESSIVELY STRONG...EACH ONE WILL BRING AT LEAST A CHANCE OF
PRECIP TO THE AREA. TWO QUESTIONS WILL SURROUND EACH PASSING WAVE OF
LOW PRESSURE HOWEVER...HOW MUCH PRECIP WILL EXTEND NORTH FROM THE
LOW...AND WHETHER COLD ENOUGH AIR WILL BE IN PLACE FOR MIXED P-TYPE.
THE FIRST OF THESE...WEDNESDAY NIGHT AND THURSDAY...LOOKS NOW TO BE
THE MOST SIGNIFICANT OF THE WEEK. GUIDANCE IS TRACKING THIS SURFACE
LOW A LITTLE FURTHER WEST THAN PREVIOUS RUNS...AND THUS SLINGING
MORE PRECIP INTO THE CAROLINAS. ADMITTEDLY...THE E-W ORIENTED
BAROCLINIC ZONE DOES NOT`T SUPPORT A VERY FAR WEST TRACK AND WILL LEAN
MORE ON THE DRIER GFS...BUT WIDESPREAD CLOUDS WITH PERIODS OF PRECIP
ARE POSSIBLE WEDNESDAY NIGHT INTO THURSDAY. WITH COLD HIGH PRESSURE
IN PLACE RAIN COULD MIX WITH SOME FREEZING/FROZEN PRECIP...EVEN
THOUGH RAIN IS EXPECTED TO BE THE PRIMARY P-TYPE. THE ECMWF...WHICH
IS MORE ROBUST WITH ITS PRECIP...IS ALSO COLDER...BUT EVEN THE GFS
DEPICTS A PERIOD OF MIXED PRECIP. LOCAL TOP-DOWN METHODOLOGY
PRODUCES PRIMARILY RAIN AS EXPECTED...BUT HAVE LEFT A PERIOD OF MIX
PRECIP...RAIN AND SNOW WITH SNOW ONLY FAR NW...LATE WED NIGHT. QPF
WILL BE LIGHT AND POP IS LOW...BUT SNOWFLAKES ARE POSSIBLE WED NIGHT
BEFORE TEMPS WARM TO SUPPORT ONLY RAIN DURING THURSDAY.
A PERIOD OF DRIER WEATHER IS EXPECTED LATE THURSDAY INTO
FRIDAY...BEFORE ANOTHER LOW PRESSURE MOVES ALONG THE STALLED
BOUNDARY TO THE SOUTH. HOWEVER...EVEN DURING THIS "DRIER" PERIOD A
SCHC POP REMAINS WARRANTED DUE TO WAVES OF LOW PRESSURE ALONG THE
OFFSHORE BAROCLINIC GRADIENT - AND THERE IS LOW CONFIDENCE IN THE
TIMING/TRACK OF THESE FEATURES. THE PAST FEW DAYS...ECMWF/GFS HAD
SHOWN GOOD AGREEMENT IN BRINGING MORE SIGNIFICANT PRECIP LOCALLY
FRIDAY INTO SATURDAY...MUCH OF WHICH WOULD BE OF THE
FREEZING-TO-LIQUID TRANSITION VARIETY. TODAY...GUIDANCE HAS BACKED
OFF CONSIDERABLY...WHICH MAY MAKE SENSE DUE TO THE EXPECTED QUICK
E/NE TRACK OF SURFACE FEATURES. STILL...AM INCLINED TO MAKE ONLY
MINIMAL CHANGES TO THE FRI/SAT TIMEFRAME AS THIS REPRESENTS A NEW
SOLUTION...AND WILL LEAVE LOW MENTIONABLE POP WITH MIXED P-TYPE.
BY SUNDAY THE LONGWAVE TROUGH WILL BEGIN TO
ERODE...FINALLY...BRINGING BRIGHTER WEATHER AND MORE SEASONABLE
TEMPERATURES AFTER THE FIRST 4 DAYS OF THE EXTENDED CONTINUE WELL
BELOW NORMAL.
&&
.AVIATION /06Z MONDAY THROUGH FRIDAY/...
AS OF 06Z...EXPECT PCPN IN THE FORM OF LIGHT RAIN TO STREAM ACROSS
THE FORECAST AREA BOTH ALONG AND BEHIND THE COLD FRONTAL
BOUNDARY. MOISTURE WILL CONTINUE TO FEED ALONG THE FRONT AS
ASSOCIATED UPPER LEVEL DISTURBANCE RIDES ALONG THE FRONT AND WILL
ENHANCE THE RAINFALL DURING THE PRE-DAWN MON HOURS INTO DAYTIME
MON MORNING. IFR AND POSSIBLY LIFR FROM BOTH CEILINGS AND VSBY
FROM BR AND FG WILL LIKELY DOMINATE ALL TERMINALS THROUGH THE PRE-
DAWN MON HOURS...WITH A SLOW IMPROVEMENT DURING DAYTIME MON
MORNING INTO THE AFTERNOON AS THE FRONT DROPS FURTHER
SOUTH...ENDING THE THREAT FOR PCPN WITH BOTH VSBY AND CEILINGS
IMPROVING. IMMEDIATELY AFTER THE CFP...WINDS WILL VEER TO 360-020
AT 5 TO 10 KT...INCREASING DURING MONDAY TO 10 TO 20 KT...WITH
SOME GUSTS IN THE 20S ESPECIALLY ACROSS THE COASTAL TERMS. THIS IN
RESPONSE TO THE COMBINED EFFORTS OF COLD AIR ADVECTION AND A
TIGHTENED SFC PRESSURE GRADIENT.
EXTENDED OUTLOOK...WAVES OF LOW PRESSURE TO AFFECT THE LOCAL AREA
DURING THE EXTENDED PERIOD...RESULTING WITH POSSIBLE LIFR/IFR/MVFR
CONDITIONS.
&&
.MARINE...
.NEAR TERM /THROUGH TONIGHT/...
AS OF 930 PM SUNDAY...WINDS ARE RELATIVELY LIGHT OVER THE WATERS
WITH SEAS RANGING FROM 2 TO 4 FEET. FRYING PAN SHOALS IS NOW
REPORTING SEAS DOWN TO 5 FEET JUST OUTSIDE THE COASTAL WATERS. A
LIGHT RAIN IS EXPECTED OVERNIGHT AS A COLD FRONT SLOWLY
APPROACHES THE WATERS BY DAYBREAK.
SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/...
AS OF 330 PM SUNDAY...SMALL CRAFT ISSUED FOR MONDAY THROUGH EARLY
TUES AS ARCTIC HIGH PRESSURE BUILDS DOWN BEHIND COLD FRONT. THIS
COLD FRONT WILL LINGER SOUTH OF AREA KEEPING TIGHTENED GRADIENT
FLOW THROUGH MON NIGHT AND ALONG WITH PLENTY OF CAA...WINDS AND
SEAS WILL RAMP UP TO 5 TO 7 FT IN STRONG NORTHERLY FLOW UP AROUND
25 KTS IN OUTER WATERS. THE STRONG N TO OFF SHORE COMPONENT WILL
KEEP HIGHEST SEAS AWAY FROM SHORE. WINDS START DECREASING TUE AS
ELONGATED SURFACE RIDGE AXIS MOVES TO THE COAST AND GRADIENT
RELAXES. LIGHT WINDS LATE TUE CONTINUE TUE NIGHT AS THE WEAK HIGH
EXITS NORTHEAST AND WINDS BACK TO WEST-SOUTHWEST. SEAS FALL TO 3
TO 5 FT LATER TUE AND 2 TO 4 FT TUE NIGHT.
LONG TERM /WEDNESDAY THROUGH FRIDAY/...
AS OF 300 PM SUNDAY...DIFFUSE PRESSURE PATTERN WEDNESDAY LEAVES A
WEAK GRADIENT AND LIGHT W-NW WINDS ACROSS THE WATERS. THIS WILL
CHANGE RAPIDLY WEDNESDAY NIGHT AND INTO THURSDAY AS A LOW PRESSURE
SYSTEM MOVES SE OF THE WATERS. THE LOW TRACK WILL REMAIN OUTSIDE THE
COASTAL WATERS...BUT THE GRADIENT AROUND THIS LOW WILL CAUSE NE
WINDS TO INCREASE STEADILY...BECOMING 15-20 KTS EARLY THURSDAY. AS
THE LOW PULLS AWAY THURSDAY NIGHT...THE GRADIENT WILL REMAIN PINCHED
THANKS TO A STALLED COLD FRONT SOUTH OF THE AREA...ALONG WHICH
ANOTHER LOW PRESSURE WILL DEVELOP AND MOVE OFF THE COAST FRIDAY.
THIS CONTINUES THE NE WINDS AT 15-20 KTS THROUGH THE END OF THE
PERIOD. SEAS WEDNESDAY WILL BE JUST 1-3 FT ON THE LIGHT AND VARIABLE
WINDS...BUT WILL INCREASE QUICKLY WED NIGHT ON THE INCREASING NE
FETCH. WAVE HEIGHTS BUILD TO 4-6 FT THURSDAY MORNING...AND THEN EVEN
A LITTLE HIGHER ON FRIDAY...AND AN EXTENDED SMALL CRAFT ADVISORY
WILL LIKELY BE NEEDED FOR MOST OF THURSDAY AND FRIDAY.
&&
.ILM WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
NC...NONE.
MARINE...SMALL CRAFT ADVISORY FROM 8 AM THIS MORNING TO 2 PM EST
TUESDAY FOR AMZ250-252-254-256.
&&
$$
SYNOPSIS...RGZ
NEAR TERM...DRH
SHORT TERM...RGZ
LONG TERM...JDW
AVIATION...DCH
AREA FORECAST DISCUSSION
NWS FORT WORTH TX
1155 PM CST SUN FEB 22 2015
.AVIATION...
NOT MUCH CHANGE TO THE PREVIOUS TAF PACKAGE WITH REGARDS TO TIMING
AND TYPE OF PRECIPITATION EXPECTED OVER THE NEXT 18 HOURS OR SO.
SOME LIGHT FREEZING DRIZZLE WILL LINGER ACROSS THE METROPLEX TAF
SITES FOR THE NEXT FEW HOURS WITH GENERALLY IFR CEILINGS. THE NEXT
ROUND OF PRECIPITATION ASSOCIATED WITH ANOTHER SHORT WAVE IS
CURRENTLY DEVELOPING ACROSS THE PERMIAN BASIN AND SHOULD ARRIVE AT
THE METROPLEX TAF SITES AROUND SUNRISE. THIS PRECIPITATION WILL
MOSTLY BE IN THE FORM OF SLEET. HIGH RES MODEL SOLUTIONS CONTINUE
TO INDICATE CONVECTIVE BANDS WITH SOME THUNDER SLEET. THE MOST
LIKELY PERIOD FOR SLEET ACROSS THE METROPLEX TERMINALS WILL BE
BETWEEN 12 AND 18Z. SLEET CHANCES WILL DECREASE AFTER 18Z EXCEPT
FOR WACO WHERE SLEET WILL BE MOST LIKELY MONDAY AFTERNOON. OVERALL
CEILINGS WILL REMAIN BETWEEN 700 AND 1000 FT THROUGH THE DAY AND
EVENING MONDAY. ALL PRECIPITATION SHOULD END BY 00Z TUESDAY.
A NORTH WIND WILL PREVAIL OVERNIGHT AT SPEEDS BETWEEN 15 AND 20
KNOTS SUSTAINED ALONG WITH SOME HIGHER GUSTS. A NORTH WIND WILL
CONTINUE ON MONDAY BUT SPEEDS SHOULD DECREASE THROUGH THE DAY AND
FALL BELOW 12 KNOTS AFTER SUNSET.
79
&&
.UPDATE...
AS THE FIRST WAVE OF PRECIPITATION ENDS THIS EVENING...A LARGE
AREA OF FREEZING DRIZZLE HAS DEVELOPED NORTH TO WEST OF THE DFW
METROPLEX INCLUDING TARRANT COUNTY. 850 MB WINDS ARE OUT OF THE
EAST OVERRUNNING THE COLD SURFACE AIR...BUT THEY HAVE PREVAILED
FROM THIS DIRECTION MOST OF THE EVENING WITHOUT DRIZZLE
DEVELOPING EARLIER IN THE NIGHT. THE RAP SHOWS A WEAK SHORTWAVE
MOVING OVERHEAD WHICH IS LIKELY PROVIDING ADDITIONAL LIFT FOR THE
DRIZZLE TO DEVELOP...IN COMBINATION WITH THE ISENTROPIC LIFT OVER
THE COLD SURFACE LAYER. THE RAP SHOWS THIS SHORTWAVE MOVING EAST
OF THE REGION BY MIDNIGHT AND EXPECT MOST OF THE DRIZZLE WILL END
AROUND THAT TIME. HOWEVER...THE DRIZZLE IS ALREADY AND WILL
CREATE A THIN LAYER OF ICE ON ELEVATED SURFACES...METAL
OBJECTS...AND LIKELY BRIDGES AND OVERPASSES THAT ALREADY DO NOT
HAVE ICE FROM THE FREEZING RAIN/SLEET EARLIER. IN
ADDITION...RESIDUAL WATER REMAINING ON ROADWAYS TONIGHT MAY FREEZE
OVERNIGHT AS TEMPERATURES FALL INTO THE 20S OVER A GOOD PORTION OF
THE REGION. HOWEVER...THE STRONG WINDS WILL CONTINUE THROUGH THE
OVERNIGHT HOURS WHICH MAY ALSO HELP TO EVAPORATE ANY WATER ON
ROADWAYS...BUT NOT WHERE DRIZZLE IS OCCURRING.
THE NEXT WAVE OF PRECIPITATION IS STILL EXPECTED TO ARRIVE BETWEEN
1-3 AM...MOVING IN FROM THE WEST OR SOUTHWEST. NO CHANGES ARE
NEEDED TO THE CURRENT WARNING AND ADVISORY PRODUCTS...HOWEVER...IF
THE NEXT ROUND OF PRECIPITATION IS SLIGHTLY FARTHER SOUTH THAN THE
LATEST GUIDANCE SUGGESTS...IT IS POSSIBLE PORTIONS OF THE ADVISORY
MAY HAVE TO BE UPGRADED TO A WARNING DUE TO HIGHER ACCUMULATIONS
OF SLEET. UNFORTUNATELY WE WILL HAVE TO WAIT AND MONITOR THE RADAR
TRENDS LATE TONIGHT AND EARLY MONDAY MORNING BEFORE BEING ABLE TO
CONFIDENTLY MAKE THAT DECISION.
82/JLD
&&
.PREV DISCUSSION... /ISSUED 400 PM CST SUN FEB 22 2015/
...SIGNIFICANT WINTER STORM TAKING SHAPE FOR OVERNIGHT AND EARLY
MONDAY ACROSS NORTH TEXAS...
.SIGNIFICANT FORECAST CHANGES...
WINTER STORM WARNING START TIME HAS BEEN MOVED UP TO START NOW.
WINTER WEATHER ADVISORY START TIME HAS BEEN MOVED UP TO 9PM.
SLEET ACCUMULATIONS HAVE BEEN BUMPED UP SLIGHTLY ACROSS THE
NORTHWEST PARTS OF THE CWA. ICE ACCUMULATIONS FROM FREEZING RAIN
HAVE BEEN NUDGED UP SLIGHTLY BUT REMAIN BELOW WARNING CRITERIA
FARTHER SOUTH. HOURLY TEMPERATURE TRENDS HAVE BEEN ADJUSTED TO
REFLECT CURRENT POSITION OF COLDER AIR. HIGH TEMPERATURES ON
MONDAY HAVE BEEN LOWERED BY 2-3 DEGREES. NO OTHER SIGNIFICANT
FORECAST CHANGES THIS AFTERNOON.
.TECHNICAL DISCUSSION...
MUCH COLDER AIR CONTINUES TO FILTER INTO NORTH TEXAS THIS
AFTERNOON WITH SUB FREEZING TEMPERATURES NOW MOVING INTO THE
NORTHWEST COUNTIES. PRECIPITATION HAS DIMINISHED IN INTENSITY
ACROSS THESE AREAS WHICH SHOULD LIMIT ANY FREEZING RAIN POTENTIAL
THROUGH THE EVENING HOURS. FARTHER EAST...A COLD RAIN WILL
CONTINUE THROUGH THE EARLY EVENING AS THE FIRST WAVE OF LIFT MOVES
TO THE NORTHEAST. TEMPERATURES ARE GENERALLY IN THE MID TO UPPER
30S AND LOWER 40S WHERE THIS PRECIPITATION IS OCCURRING SO NO
FREEZING RAIN IS EXPECTED. SOME AREAS HAVE ALREADY PICKED UP CLOSE
TO AN INCH OF RAIN BUT THIS INTENSITY WILL DIMINISH THROUGH
EVENING.
SIGNS OF THE SECOND WAVE OF ASCENT ARE ALREADY BEING INDICATED ON
RADAR AND WATER VAPOR IMAGERY ACROSS WEST TEXAS. SOME AREAS OF
PRECIPITATION HAVE ALREADY DEVELOPED BUT THIS SHOULD GENERALLY
REMAIN SCATTERED OVER THE NEXT SEVERAL HOURS AS THE BETTER FORCING
WILL ARRIVE DURING THE OVERNIGHT HOURS. WE ARE EXPECTED TO SEE A
LULL IN THE PRECIPITATION LATER THIS EVENING THROUGH MIDNIGHT OR
SO...BUT IT WONT BE COMPLETELY VOID OF ACTIVITY. THERE WILL LIKELY
BE INTERMITTENT AREAS OF PRECIPITATION THAT DEVELOP IN POCKETS OF
STRONGER FORCING THAT STREAM ACROSS NORTH TEXAS IN THE SOUTHWEST
FLOW ALOFT. ANY PRECIPITATION THAT DEVELOPS LATE THIS EVENING
COULD BE IN THE FORM OF A FREEZING RAIN/SLEET MIX ACROSS THE WEST
AND NORTHWEST PARTS OF THE CWA. THE FREEZING LINE WILL SURGE SOUTH
THIS EVENING ACROSS THE WESTERN COUNTIES AND IT WILL TAKE A LITTLE
LONGER FARTHER EAST. IT SHOULD BE MOVING INTO THE METROPLEX BY 0Z
OR A LITTLE LATER. BY 3-4AM...MOST AREAS WITH THE EXCEPTION OF THE
SOUTHEAST COUNTIES SHOULD BE AT OR BELOW FREEZING.
THE STRONGEST FORCING LOOKS LIKE IT WILL OVERSPREAD NORTH TEXAS IN
THE 3-5AM TIMEFRAME WITH WIDESPREAD PRECIPITATION CONTINUING INTO
THE MORNING HOURS ON MONDAY. THE COMPACT UPPER LOW SOUTH OF
CALIFORNIA IS IN THE PROCESS OF EJECTING NORTHEAST NOW AND ANOTHER
DISTURBANCE APPEARS TO BE EMBEDDED IN THE FLOW ACROSS NORTHWEST
MEXICO. THESE SEEM TO BE THE FEATURES THAT REALLY PROVIDE THE
FORCING FOR ASCENT LATE TONIGHT. RIGHT NOW... WE THINK THE
HEAVIEST PRECIPITATION WILL OCCUR ALONG A LINE FROM NEAR EASTLAND
TO DFW TO SHERMAN...AND AREAS NORTHWEST OF THERE THROUGH ABOUT
10AM ON MONDAY. LATEST HIGH RESOLUTION TTU-WRF AND 4KM NAM
CONTINUE TO YIELD HIGH CONFIDENCE IN THE CURRENT FORECAST AS BOTH
CONTINUE TO STRONGLY INDICATE CONVECTIVE ELEMENTS TO THE
PRECIPITATION. SREF PLUMES OF MUCAPE AND ANALYSIS OF ALL AVAILABLE
FORECAST SOUNDINGS INDICATE THAT ANYWHERE FROM 100-150J/KG OF
ELEVATED INSTABILITY WILL BE PRESENT. THIS WILL SUPPORT
THUNDERSLEET THROUGH THE MORNING HOURS. BURSTS OF SLEET CAN
QUICKLY ACCUMULATE TO AN INCH OR MORE IN A SHORT PERIOD OF TIME.
AS OF THIS AFTERNOON...WE THINK THAT MOST AREAS IN THE CURRENT
WARNING WILL SEE BETWEEN 1/2 AND 1 INCH OF SLEET. FARTHER
NORTHWEST...FROM FORT WORTH TO BOWIE...ACCUMULATIONS OF 1 TO 1 1/2
INCH OF SLEET WITH HEAVIER AMOUNTS WILL BE POSSIBLE. SOME LIGHT
FREEZING RAIN WILL ALSO BE POSSIBLE THROUGH MORNING BUT ICE
ACCUMULATIONS SHOULD GENERALLY BE LESS THAN 1/10 OF AN INCH.
FARTHER SOUTH OF THE METROPLEX...WHERE THE CURRENT ADVISORY IS
POSTED...THE WARM NOSE WILL BE A LITTLE MORE STOUT INITIALLY.
THIS MAY KEEP PRECIPITATION ALL LIQUID AS OPPOSED TO SLEET. WITH
TEMPERATURES FALLING BELOW FREEZING...SOME LIGHT ICING IS
EXPECTED. THIS WILL BE WORST ON BRIDGES AND OVERPASSES. MOST OF
THE PRECIPITATION SHOULD MOVE EAST OF THE AREA BY LATE MONDAY BUT
WE WILL KEEP SOME LOW CHANCES IN THROUGH THE EVENING. SOME LIGHT
FREEZING RAIN OR DRIZZLE MAY BE POSSIBLE DURING THIS TIME WITH
LITTLE ADDITIONAL IMPACT.
TEMPERATURES ON MONDAY ARE NOT EXPECTED TO RISE ABOVE FREEZING SO
ANY ACCUMULATIONS OF SLEET/ICE WILL NOT MELT. THIS WILL RESULT IN
CONTINUED TRAVEL PROBLEMS. TEMPERATURES ARE EXPECTED TO RISE ABOVE
FREEZING BY MIDDAY TUESDAY.
LITTLE CHANGES MADE TO THE END OF THE WEEK SYSTEM AS THERE IS
STILL CONSIDERABLY MODEL UNCERTAINTY. WE HAVE CONTINUED WITH A
RAIN/SNOW MIX LATE THURSDAY INTO LATE FRIDAY ACROSS MUCH OF THE
AREA.
DUNN
&&
.PRELIMINARY POINT TEMPS/POPS...
DALLAS-FT. WORTH, TX 26 27 25 39 31 / 80 100 20 20 10
WACO, TX 30 31 24 38 33 / 80 90 30 20 30
PARIS, TX 25 25 25 36 28 / 50 100 30 20 10
DENTON, TX 23 25 20 36 29 / 80 100 10 10 10
MCKINNEY, TX 26 26 23 38 28 / 70 100 20 10 10
DALLAS, TX 28 29 26 39 31 / 80 100 20 20 10
TERRELL, TX 29 29 25 37 30 / 70 100 20 20 10
CORSICANA, TX 30 30 26 38 32 / 70 90 30 20 20
TEMPLE, TX 31 32 25 40 34 / 90 90 30 20 30
MINERAL WELLS, TX 24 25 20 36 28 / 100 100 10 10 10
&&
.FWD WATCHES/WARNINGS/ADVISORIES...
WINTER STORM WARNING UNTIL 6 PM CST MONDAY FOR TXZ091>095-
100>107-115>123-129>134-141.
WINTER WEATHER ADVISORY UNTIL 6 PM CST MONDAY FOR TXZ135-142>148-
156>162-174-175.
&&
$$
79/82
AREA FORECAST DISCUSSION
NWS SAN ANGELO TX
1101 PM CST Sun Feb 22 2015
.AVIATION...
/06Z TAFS/
Generally IFR/LIFR conditions are being experienced at all TAF sites
late this evening and should continue through Tuesday morning. Areas
of light freezing drizzle are also occurring. Freezing rain/sleet is
forecast to develop after midnight, mainly affecting KABI and KSJT,
then moving east of the area by mid morning Monday. Areas of light
freezing drizzle may continue into early afternoon Monday. Northeast
winds of 12 to 20 knots, with higher gusts, will diminish to 8 to 12
knots late Monday morning.
&&
.PREV DISCUSSION... /ISSUED 955 PM CST Sun Feb 22 2015/
UPDATE...
Based on radar data, it appears we`re in a bit of a lull across
the area now. However, calls across the CWA and automated surface
observations indicate that widespread, light freezing drizzle is
occurring in many areas. Temperatures continue to run a few
degrees below even the coldest guidance, with current readings in
the 20s everywhere excluding the I-10 corridor (lower 30s).
Temperatures will continue to slowly drop tonight, setting
the stage for the next shortwave trough.
The primary wave looks to be moving across the northern Baja
Peninsula at this time, with notable forced ascent downstream
over AZ, NM, and northern Mexico. There is a band of frontogenetic
forcing sloping up and over the cold dome from north to south that
is progged to persist into Monday morning before weakening. This
area of mesoscale lift should be enhanced by the approaching
shortwave energy. The going forecast looks to be in relatively
good shape. The wx grids were modified for this evening, with
widespread drizzle and only a chance for sleet mentioned areawide.
However, after midnight, we expect additional precipitation to
develop.
Point soundings suggest the favored precipitation types to be
sleet and freezing rain. However, both the NAM and RAP soundings
show the cold near surface layer (below the inversion) to be near
-10C. While this generally favors supercooled liquid hydrometeors,
this is a borderline temperature for the activation of ice nuclei.
This would account for the very light snow we`ve had reported over
the past few hours. Expect snow accumulations to be a dusting or
less. With elevated instability in place, this precipitation
should be more convective in nature, with the potential for
thundersleet overnight. In areas that do experience thunder, the
enhanced convective updrafts may lead to localized higher amounts
of sleet and/or snow.
Precipitation is expected to diminish by Monday afternoon,
although freezing drizzle will remain possible even into Monday
evening. Expect surface temperatures on Monday to remain well
below freezing, with highs in the mid/upper 20s. There may be just
enough radiation coming through the thick overcast to improve road
surfaces on Monday, but most of the ice should persist into
Tuesday morning.
Johnson
PREV DISCUSSION... /ISSUED 514 PM CST Sun Feb 22 2015/
AVIATION...
/00Z TAFS/
Generally LIFR/IFR conditions are being experienced at all sites
this evening and are forecast to continue through the next 24
hours. Light freezing drizzle continues at KABI and is forecast
to develop at KSJT around 00z as temperatures drop to or below
freezing. Light drizzle will continue at the other sites then
transition to light freezing drizzle late this evening as
temperatures drop below freezing. Areas of light freezing
rain/sleet may develop after midnight, mainly at KABI and KSJT.
Northeast winds of 12 to 20 knots, with higher gusts, will
decrease to 8 to 12 knots by late morning Monday.
PREV DISCUSSION... /ISSUED 409 PM CST Sun Feb 22 2015/
SHORT TERM...
(Tonight through Tuesday morning)
The much talked about winter storm is beginning to affect the
area. Another cold front was crossing the area at 3 PM and was
located along an Ozona to just south of Brownwood line, with cold
air rapidly invading the area behind this front. Trends in the
observations are showing temperatures dropping 5 to 10 degrees per
hour behind it. In fact, many areas along/north of Interstate 20
have already dropped below freezing with freezing rain, sleet, and
ice accumulations already occurring per social media, phone calls,
and observations. Given these developments over the last few
hours, and after coordinating with surrounding offices, the Winter
Storm Warning start time has been increased to 4 PM this
afternoon.
Things continue to look like they`ll get messy through tomorrow.
The numerical models remain consistent dropping temperatures
into the lower to mid 20s across the warned area, and near
freezing farther south, with not much recovery tomorrow afternoon.
They have also trended stronger/farther south with their
convective signature. The Storm Prediction Center has most of West
Central Texas in a risk for thunder tonight/tomorrow and model
soundings show 100-250 J/kg of MUCAPE across the entire forecast
area during this period. As a result, thunder was included in all
zones for tonight through mid afternoon tomorrow.
LONG TERM...
(Tuesday through Sunday)
All hands on board for the first winter storm, so this part of the
discussion will be brief. Warming trend starts on Tuesday
afternoon, although it will be modest. A few breaks in the clouds
will allow a little sun, enough to allow temperatures to climb
into the 40s. Another upper level low will drop into the southwest
US, with return flow ahead of it allowing readings to climb into
the 60s on Wednesday. Next arctic front moves across the area for
Thursday and Friday, just ahead of the upper level trough moving
across. GFS and the ECMWF have some differences in the strength of
this system, with the GFS shearing it out a little faster. For
now, kept the compromise intact and have slight chance to chance
PoPs across the area. Models did warm just a tad, so was able to
shift the mention of snow a little farther north.
&&
.PRELIMINARY POINT TEMPS/POPS...
Abilene 21 25 20 40 29 / 90 80 10 10 5
San Angelo 25 29 25 46 31 / 90 70 10 10 5
Junction 29 32 28 48 34 / 80 70 10 10 10
&&
.SJT WATCHES/WARNINGS/ADVISORIES...
WINTER STORM WARNING until 6 PM CST Monday FOR THE FOLLOWING
ZONES: Brown...Callahan...Coke...Coleman...Concho...Fisher...
Haskell...Irion...Jones...Nolan...Runnels...Shackelford...
Sterling...Taylor...Throckmorton...Tom Green.
WINTER WEATHER ADVISORY until 6 PM CST Monday FOR THE FOLLOWING
ZONES: Crockett...Kimble...Mason...McCulloch...Menard...San
Saba...Schleicher...Sutton.
&&
$$
Daniels
AREA FORECAST DISCUSSION
NWS GREEN BAY WI
1130 PM CST SUN FEB 22 2015
UPDATED AVIATION PORTION FOR 06Z TAF ISSUANCE
.SHORT TERM...TONIGHT AND MONDAY
ISSUED AT 231 PM CST SUN FEB 22 2015
THE LATEST RAP ANALYSIS AND SATELLITE/RADAR IMAGERY SHOW ARCTIC HIGH
PRESSURE DRIFTING SOUTHEAST OVER THE NORTHERN GREAT PLAINS EARLY
THIS AFTERNOON. THOUGH COLD ADVECTION IS ONGOING...HEATING HAS
SERVED TO STEEPEN LOW LEVEL LAPSE RATES...WHICH TRIGGERED A CU FIELD
TO FORM LATE IN THE MORNING. DRY AIR IS WINNING OUT THIS AFTERNOON
AS EVIDENT BY THE CU FIELD DIMINISHING. ONLY CLEAR AND BITTERLY
COLD CONDITIONS EXIST UPSTREAM...SO FORECAST CONCERNS INCLUDE TEMPS
AND WIND CHILLS THROUGH MONDAY.
TONIGHT...STRONG ARCTIC HIGH PRESSURE WILL BE SLIDING SOUTHEAST FROM
THE NORTHERN GREAT PLAINS TO CENTRAL IOWA. LOSS OF DIURNAL HEATING
WILL CAUSE ANY LINGERING CU TO DISSIPATE BY EARLY THIS
EVENING...WHICH WILL LEAVE CLEAR SKIES FOR MUCH OF THE NIGHT.
BECAUSE THE ARCTIC HIGH WILL DROP SOUTHWEST OF THE REGION...BOTH
STATISTICAL AND NUMERICAL GUIDANCE POINT TOWARDS WINDS REMAINING IN
THE 5 TO 10 KT RANGE THIS EVENING...BEFORE DIMINISHING SOME
OVERNIGHT. SOME POTENTIAL FOR DECOUPLING OVER N-C WISCONSIN AS
BOUNDARY LAYER WINDS LIGHTEN. AS A RESULT...THINK TEMPERATURES HAVE
A CHANCE TO TUMBLE LATE TONIGHT. THIS MAKES FOR A DILEMMA IN TERMS
OF HEADLINE DECISIONS. IF WINDS REMAIN IN THE 4-5 KT RANGE...SOME
PLACES LIKE ANTIGO AND RHINELANDER COULD REACH WIND CHILL WARNING
CRITERIA FOR A PERIOD LATE TONIGHT INTO MONDAY MORNING. THINK
WARNING CONDITIONS WILL NOT BE WIDESPREAD ENOUGH DUE TO WINDS
DROPPING OFF. SO WILL STICK WITH THE ADVISORY THROUGH THE NIGHT AND
CONTINUE TO MENTION THAT SOME SPOTS WILL HIT WARNING CRITERIA. IF
WINDS DO DROP OFF...TEMPS 25 TO 30 BELOW ARE POSSIBLE.
MONDAY...HIGH PRESSURE WILL BE DRIFTING TO THE MID-MISSISSIPPI
VALLEY WHILE THE NEXT CLIPPER WILL REACH NORTHERN MINNESOTA LATE IN
THE AFTERNOON. A TIGHTENING PRESSURE GRADIENT BETWEEN THESE
FEATURES WILL CAUSE WINDS TO SWING AROUND TO THE SOUTHWEST AND
BECOME GUSTY IN THE AFTERNOON. BUT THE SOUTHWEST WINDS WILL ALSO
HELP MODERATE THE BITTERLY COLD AIRMASS. WIND CHILLS WILL BE
WARMING ABOVE ADVISORY CRITERIA BY LATE IN THE MORNING SO THE ENDING
TIME LOOKS ABOUT RIGHT. THOUGH CIRRUS WILL BE INCREASING IN THE
AFTERNOON...HIGHS WILL WARM INTO THE UPPER SINGLE DIGITS TO THE
LOWER TEENS.
.LONG TERM...MONDAY NIGHT THROUGH SUNDAY
ISSUED AT 231 PM CST SUN FEB 22 2015
OVERALL UPPER LEVEL PATTERN CONSISTING OF A WESTERN RIDGE AND
EASTERN TROUGH WILL REMAIN FOR MOST OF THE PERIOD...ALTHOUGH THERE
ARE HINTS THAT THE WESTERN RIDGE MAY REORGANIZE FURTHER WEST OVER
THE PACIFIC WHILE FLOW OVER THE UNITED STATES TAKES ON MORE OF AN
APPEARANCE OF SPLIT FLOW. THIS CHANGE DOES NOT LOOK LIKE IT WILL
DO MUCH TO REVERSE OUR TREND OF SEEING TEMPS WELL BELOW
NORMAL. FOR NOW...ONLY TUESDAY LOOKS TO SEE HIGHS RELATIVELY NEAR
NORMAL...WITH A RETURN TO COLD WEATHER AFTER A FRONT MOVES
THROUGH.
THE PRIMARY CHANCE FOR MEASURABLE SNOW LOOKS TO BE MONDAY NIGHT
AND TUESDAY AS A LOW PRESSURE PASSES NORTH THROUGH ONTARIO...WITH
AN ATTACHED COLD FRONT PUSHING ACROSS THE AREA ONCE AGAIN. GUIDANCE
CONTINUES TO LIKE OUR FAR NORTH FOR THE BEST CHANCE AND AMOUNTS OF
SNOW...TO BE EXPECTED AS THE LOW PASSES SOME DISTANCE TO OUR NORTH
AND EAST. HOWEVER...THE GFS AND TO SOME EXTENT THE GEM PROVIDE
BETTER MOISTURE AND LIFT...AND BRING AN INCH OR TWO OF SNOW DOWN
THROUGH A LARGE PORTION OF THE NORTHEAST QUARTER OF WISCONSIN. IT
IS WORTH NOTING THAT THE GFS ENSEMBLE CONTINUES TO NOT BE AS
ENAMORED OF THIS IDEA AS THE DETERMINISTIC RUN. IN GENERAL WILL
FOLLOW SUIT...PUTTING THE HIGHEST POPS AND ACCUMULATIONS IN FAR
NORTHERN WISCONSIN...BUT WILL PAY SOME DEFERENCE TO THE NORTH
AMERICAN MODELS AND THEIR PLAUSIBLE...IF NOT AS CONVINCING...IDEA
OF MORE SNOW FURTHER TO THE SOUTH AND WEST WITH CHANCE POPS
TUESDAY MORNING.
ALONG WITH THIS SNOW...OUR POSITION BETWEEN THIS ONCOMING
LOW AND THE HIGH RESPONSIBLE FOR OUR MOST RECENT COLD PLUNGE WILL
RESULT IN GUSTY SOUTHWEST WINDS MONDAY NIGHT INTO TUESDAY. THIS
COULD CREATE SOME BLOWING AND DRIFTING OF ANY SNOW THAT MAY
FALL...EVEN IF AMOUNTS ARE NOT PARTICULARLY HIGH. GUIDANCE IS
UNANIMOUS IN STRONG 50 TO 65 KNOT WINDS AT RELATIVELY LOW ALTITUDE
VERY EARLY TUESDAY MORNING. SOUNDINGS IN BUFKIT SHOW POTENTIAL
GUSTS TO 20-30 KTS...AND GUSTS EVEN A LITTLE HIGHER ARE NOT OUT OF
THE QUESTION...THOUGH THIS SCENARIO WOULD NEED BETTER MIXING TO
COME TO FRUITION.
AFTERWARDS...HIGH PRESSURE SETTLES OVER THE AREA BRINGING DRY
WEATHER THROUGH SATURDAY. IN WHAT SURELY IS BEGINNING TO SOUND ALL
TOO FAMILIAR...WE WILL SEE ANOTHER SHOT OF WELL BELOW NORMAL
TEMPERATURES. THE COLDEST PERIOD LOOKS TO BE TUESDAY NIGHT THROUGH
THURSDAY. HIGHS ON WEDNESDAY LOOK TO BE MIRED IN THE SINGLE DIGITS
FOR MOST...WITH SUBZERO LOWS ON TAP TUESDAY AND WEDNESDAY NIGHT.
A SLOW MODERATION IN TEMPERATURES IS EXPECTED THROUGH THE WEEKEND.
ANOTHER CHANCE FOR PRECIPITATION EMERGES DURING THE WEEKEND...BUT
WITH A GOOD BIT OF UNCERTAINTY IN THE NATURE OF THE UPPER
FLOW...WILL NOT SPECULATE ON THE DETAILS FOR NOW.
&&
.AVIATION...FOR 06Z TAF ISSUANCE
ISSUED AT 1130 PM CST SUN FEB 22 2015
VFR CONDITIONS TO PREVAIL TNGT THRU MON EVENING AS A LARGE AREA
OF HI PRES MOVES FROM THE NRN PLAINS SE TOWARD THE OHIO RIVER
VALLEY. WINDS ARE FCST TO SLOWLY BACK FROM W-NW OVRNGT...TO WEST
MON MORNING...TO SW MON AFTERNOON. THE PRES GRADIENT WL GRADUALLY
TIGHTEN MON AFTERNOON BETWEEN THE HI PRES TO OUR SOUTH AND AN
AREA OF LOW PRES RESIDING WELL TO OUR NORTH. WIND GUSTS COULD
APPROACH 20 KTS BY LATE MON AFTERNOON AND 25 KTS MON EVENING. NE
WI WL ALSO SEE AN INCREASE IN HI CLOUDS MON AFTERNOON WITH MID
CLOUDS ARRIVING MON EVENING AHEAD OF A CDFNT THAT IS FCST TO MOVE
THRU THE AREA ON TUE.
&&
.GRB WATCHES/WARNINGS/ADVISORIES...
WIND CHILL ADVISORY UNTIL 10 AM CST MONDAY FOR WIZ005-010>013-
018>022-030-031-035>040-045-048>050-073-074.
&&
$$
SHORT TERM.....MPC
LONG TERM......LUCHS
AVIATION.......AK
AREA FORECAST DISCUSSION
NWS DENVER/BOULDER CO
329 AM MST MON FEB 23 2015
.SHORT TERM...(TODAY THROUGH TONIGHT )
ISSUED AT 329 AM MST MON FEB 23 2015
WK SWLY FLOW ALOFT THIS MORNING WILL BECOME LIGHT NNW BY LATE AFTN
AND CONTINUE TONIGHT. LINGERING MOISTURE EARLY THIS MORNING MAY
ALLOW FOR A FEW AREAS OF VERY LIGHT SNOW IN THE FOOTHILLS AND OVER
PORTIONS OF NERN CO THRU 15Z. IN THE MTNS BEST CHC OF SNOW WILL BE
ALONG AND SOUTH OF I-70 WHICH MAY LINGER THRU THE AFTN HOURS AS
ACTIVITY BECOMES MORE CONVECTIVE DUE TO FAVORABLE LAPSE RATES. AS
FOR HIGHS WILL KEEP READINGS MAINLY IN THE 20-25 RANGE ACROSS NERN
CO.
FOR TONIGHT ANY LINGERING SNOW IN THE MTNS SHOULD END THIS EVENING
WITH DRY CONDITIONS ELSEWHERE.
.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 329 AM MST MON FEB 23 2015
AN ACTIVE AND VERY WINTRY WEATHER PATTERN WILL REMAIN IN PLACE
THROUGH THE UPCOMING WEEK.
TUESDAY IS SHAPING UP TO BE THE MOST QUIET AND WARMEST DAY OF THE
WEEK WITH MOSTLY SUNNY SKIES AND WARM ADVECTION ALOFT.
HOWEVER...ABUNDANT SNOW COVER AND LACK OF DOWNSLOPE WILL LIMIT THE
AMOUNT OF WARMING. WE SHOULD STILL SEE HIGHS APPROACH 40F OVER
SNOW COVERED AREAS OF THE PLAINS...WITH MID/UPPER 40S OVER THE
FAR NORTHEAST CORNER WHERE ONLY A LIGHT DUSTING OF SNOW OCCURRED
WITH THIS LAST STORM.
WEDNESDAY WILL SEE ANOTHER CHANGE. WE SHOULD SEE OROGRAPHIC SNOW
DEVELOP ACROSS THE MOUNTAINS AS EARLY AS LATE TUESDAY NIGHT OR
WEDNESDAY MORNING AS MOISTURE INCREASES AHEAD OF NEXT FAST MOVING
SHORT WAVE. BY LATE MORNING INTO THE AFTERNOON...EXPECT SHOWERS TO
SPILL ACROSS THE PLAINS AND INCREASE IN COVERAGE THROUGH THE
AFTERNOON HOURS BEHIND COLD FRONTAL PASSAGE. SEEMS MODELS ARE A
BIT FASTER WITH THIS COLD FRONT SO SHOULD SEE FALLING TEMPERATURES
AND GUSTY NORTH WINDS ACROSS THE PLAINS THROUGH THE AFTERNOON.
WITH REGARD TO SNOW POTENTIAL...WE DO EXPECT ACCUMULATING
SNOWFALL ACROSS THE MOUNTAINS...FOOTHILLS...AND NEARBY PLAINS
INCLUDING THE I-25 URBAN CORRIDOR WHERE UPSLOPE FLOW WILL ACT TO
FOCUS PRECIPITATION. UPSLOPE IS EXPECTED TO DEEPEN TO 700 MB OR
MORE IN NORTHWEST FLOW ALOFT...AND LAPSE RATES WILL BE NEARLY
NEUTRAL THROUGH A DEEP LAYER DURING THE WEDNESDAY AFTERNOON/EARLY
EVENING HOURS. Q-G FIELDS ALSO SUPPORT DEEP BUT MODEST LIFT DURING
THIS PERIOD. AS A RESULT...CONTINUED TREND OF INCREASING POPS NEAR
THE FRONT RANGE...WITH POTENTIAL FOR A FEW INCHES OF ACCUMULATION.
THE EASTERN PLAINS WILL ALSO SEE A GOOD CHANCE OF SNOW...BUT LACK
OF STRONGER UPSLOPE FORCING WILL LIKELY LIMIT ACCUMULATION
POTENTIAL THERE.
BY THURSDAY...SOME MODELS ARE POINTING AT ANOTHER BUT WEAKER SHORT
WAVE IN NORTHWEST FLOW ALOFT. THIS WILL KEEP A CHANCE OF SOME SNOW
IN THE FORECAST...WHILE COLDER AIR ALSO REMAINS FIRMLY ENTRENCHED
EAST OF THE ROCKIES. HAVE KEPT A COLD FORECAST IN PLACE WITH TEMPS
LIKELY STRUGGLING TO REACH 20F ON THE PLAINS PER LATEST GRIDDED
TEMP OUTPUT.
AT THIS TIME...FRIDAY INTO SATURDAY APPEAR TO BE MAINLY IN
BETWEEN WEATHER SYSTEMS. HOWEVER...HARD TO ELIMINATE SNOW CHANCES
WITH SOME MOISTURE IN NORTHWEST FLOW ALOFT FRIDAY...AND POSSIBLE
FASTER ARRIVAL OF NEXT STORM SYSTEM BY SATURDAY. TEMPERATURES
SHOULD MODERATE DURING THIS TIME FRAME BUT REMAIN A GOOD 15
DEGREES BELOW NORMAL EVEN INTO SATURDAY.
FOR LATE SATURDAY INTO SUNDAY...SNOW CHANCES WOULD INCREASE AGAIN
AS LATEST MEDIUM RANGE GUIDANCE AND ENSEMBLES SHOW ANOTHER BUT
DEEPER TROUGH HEADED INTO THE SOUTHWEST U.S. WILL GO WITH ABOVE
CLIMATOLOGY POPS FOR THIS PERIOD GIVEN THE REASONABLE AGREEMENT IN
MODEL SOLUTION OF TROUGHINESS/FRONTAL PASSAGES.
&&
.AVIATION...(FOR THE TAFS THROUGH 12Z TUESDAY MORNING)
ISSUED AT 329 AM MST MON FEB 23 2015
THERE COULD BE SOME VERY LIGHT SNOW THRU 15Z HOWEVER NO
ACCUMULATIONS ARE EXPECTED. WK DENVER CYCLONE WAS OVER DIA EARLY
THIS MORNING AND MAY STAY NR THE AIRPORT THRU MIDDAY. WITH THIS TYPE
OF SITUATION ALWAYS HAVE TO BE AWARE OF SOME POTENTIAL FOG/STRATUS
HOWEVER HRRR KEEPS IT MAINLY WEST AND SOUTH DIA FOR NOW.
WINDS NEAR THE CYCLONE WILL BE VARIABLE AROUND 5KTS THIS MORNING.
BY MIDDAY THE WK CYCLONE MAY MOVE TO THE EAST OF NE OF DIA WITH
LIGHT NNW WINDS DEVELOPING. FOR TONIGHT WINDS SHOULD BECOME LIGHT
DRAINAGE BY EARLY EVENING. VFR CONDITIONS ARE EXPECTED THIS AFTN
AND TONIGHT.
&&
.BOU WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...RPK
LONG TERM...BARJENBRUCH
AVIATION...RPK
AREA FORECAST DISCUSSION
NWS MELBOURNE FL
544 AM EST MON FEB 23 2015
.UPDATE...WIDESPREAD DENSE FOG OVER WESTERN FLORIDA PENINSULA IS
SLOWLY ADVECTING EASTWARD AND MOVING INTO LAKE COUNTY EARLY THIS
MORNING BASED ON LATEST SATELLITE AND SFC OBS. NOT QUITE SURE HOW
FAR EASTWARD THIS MORE WIDESPREAD FOG WILL BE ABLE TO TRAVEL
BEFORE DAYTIME HEATING BEGINS TO SET IN THIS MORNING. FOR NOW
HAVE JUST DECIDED TO ISSUE A DENSE FOG ADVISORY FOR LAKE
COUNTY...BUT WILL CONTINUE TO MONITOR FOR ANY ADDITIONAL
EXPANSION.
&&
.PREV DISCUSSION... /ISSUED 348 AM EST MON FEB 23 2015/
DISCUSSION...
TODAY/TONIGHT...COLD FRONT CURRENTLY JUST NORTH OF FL WILL WEAKEN AS
IT SHIFTS SWEETHEART AND EVENTUALLY INTO THE AREA TONIGHT. ANY
FOG/STRATUS INITIALLY OVER THE REGION WILL BURN OFF BY LATE MORN
WITH PARTLY CLOUDY SKIES EXPECTED THROUGH MUCH OF THE DAY. TEMPS
WILL REMAIN ABOVE NORMAL WITH HIGHS RANGING FROM THE UPPER 70S OVER
LAKE AND VOLUSIA COUNTY TO LOW 80S FARTHER SOUTH. MODELS SHOW A
LITTLE HIGHER MOISTURE WORKING INTO NRN AREAS LATER IN THE AFT AHEAD
OF THE FRONT WHICH MAY LEAD TO A FEW SHRAS...SO HAVE INCLUDED SLIGHT
CHANCE POPS NORTH OF ORLANDO. THE LATEST HRRR INDICATES SOME ISO
SHRA ACTIVITY EVEN FARTHER SOUTH BY LATE DAY BUT LOW LEVEL MOISTURE
IS FAIRLY SHALLOW AND MOS POPS REMAIN BELOW MENTIONABLE LEVELS SO
WILL KEEP RAIN CHANCES OUT OF THE FORECAST ELSEWHERE.
AS FRONT MOVES INTO CENTRAL FLORIDA TONIGHT RAIN CHANCES WILL
CONTINUE TO INCREASE SLIGHTLY MAINLY OVER NORTHERN PORTIONS OF THE
AREA. ALSO CLOUD COVER WILL INCREASE AS LOW CLOUD DECK BUILDS IN
BEHIND THE BOUNDARY. SINCE FRONT WILL BE WEAK...OVERNIGHT TEMPS WILL
STAY ABOVE NORMAL WITH LOWS IN THE UPPER 50S TO LOW 60S.
TUE...WEAK COLD FRONT SHOULD SHIFT TO THE SOUTHERN SECTIONS.
FORECAST SOUNDINGS SHOW A SHALLOW COOL AIR MASS WITH CONSIDERABLE
LOW CLOUDINESS ESPECIALLY ACROSS THE NORTH HALF. ISENTROPIC LIFT
WILL BE SHALLOW/WEAK SO EXPECT ONLY SCATTERED LIGHT PRECIP. MAX
TEMPS WILL BE KNOCKED DOWN CONSIDERABLY ACROSS THE NORTH WITH THE
CLOUD COVER AND NORTHERLY WIND FLOW. SOUTHERN SECTIONS WILL HAVE A
LITTLE MORE CLOUDINESS DEVELOPING IN THE AFTERNOON BUT MAX TEMPS
SHOULD STILL BE 80 AROUND OKEECHOBEE.
TUE NIGHT...A WEAK LOW EAST OF THE COASTAL WATERS IS FORECAST TO
PULL AWAY TO THE NORTHEAST BUT THE WEAK/SHALLOW FRONTAL BOUNDARY
SHOULD CONTINUE TO EXTEND ACROSS THE SOUTHERN PENINSULA. MOS POPS
ARE 20-30 PERCENT...BUT THE MAIN CONCERN MAY ACTUALLY TURN OUT TO
BE LOW STRATUS/FOG. WILL NOT MENTION YET AND KEEP POPS AT 20
PERCENT OR LESS.
WED-THU...THE 00Z GFS/ECMWF HAVE COME INTO GOOD AGREEMENT DURING
THIS PERIOD. THE MAIN FEATURE WILL BE A SOUTHERN STREAM SHORTWAVE
TROUGH THAT MOVES ACROSS THE DEEP SOUTH WED WHILE GRADUALLY
DAMPENING OUT. THE ACCOMPANYING SURFACE LOW IS FORECAST TO PUSH
INTO NORTH FLORIDA WED AFTERNOON AND SHIFT TO OFFSHORE THE
CAROLINAS BY 12Z THU.
THE WARM SECTOR WILL ENCOMPASS THE LOCAL AREA AS LOW LEVEL WINDS
BECOME SOUTHERLY AND INCREASE WED INTO WED NIGHT. THE MODELS SHOW
MAIN PRECIP OCCURRING NEAR A WARM FRONT TO OUR NORTH ON WED THEN
AS COLD FRONT DROPS TOWARDS THE AREA OVERNIGHT...A BAND OF
CONVECTION WILL ACCOMPANY IT. THE BAND OF CONVECTION SHOULD SHIFT
INTO SOUTHERN SECTIONS ON THU.
HAVE NOT MADE MUCH CHANGE TO THE PREVIOUS FORECAST WHICH HAS
CHANCE POPS NORTH AND SLIGHT CHANCE IN THE SOUTH WED AND WED
NIGHT...EXCEPT BECOMING LIKELY IN THE NORTH WED NIGHT. CHANCE
POPS SHOULD BE A LITTLE HIGHER IN THE SOUTH ON THU.
WITH QUITE STRONG LOW LEVEL WINDS AS SURFACE LOW MOVES BY JUST TO
OUR NORTH...THE MENTION OF ISOLATED STORMS LOOKS GOOD WED NIGHT
ESPECIALLY NORTH HALF...WITH A SLIGHT CHANCE THAT STORMS COULD BE
STRONG.
FRI-NEXT MON...LARGE HIGH PRESSURE CENTERED OVER THE MID PART OF
THE COUNTRY SHOULD PUSH FRONTAL BOUNDARY INTO THE NORTHERN BAHAMAS
ON FRI BUT THE MODELS SHOW FRONT HANGING UP AND THE ASSOCIATED
MOISTURE FROM IT LIFTING BACK NORTH. THIS WILL ALLOW A MENTION OF
SLIGHT CHANCE TO CHANCE POPS THROUGH THE WEEKEND.
TEMPERATURES GENERALLY EXPECTED TO STAY NEAR TO JUST BELOW SEASONAL
NORMS FRI THEN MODERATE SAT AS BREEZY ONSHORE FLOW DEVELOPS...THEN
BE ABOVE NORMAL BY SUN AS BREEZY ONSHORE CONTINUES. A DEEP LAYER
HIGH PRESSURE RIDGE IS INDICATED OVER THE AREA NEXT MON...SO A
WARM AND DRY DAY LOOKS TO BE ON TAP.
&&
AVIATION...PATCHY/AREAS OF FOG THROUGH EARLY MORNING WILL PRODUCE
TEMPO IFR/MVFR CONDS THROUGH 13-14Z. ANY FOG SHOULD THEN BURN OFF
WITH VFR CONDS EXPECTED INTO THE AFT. WEAK FRONT MOVING INTO THE
REGION TONIGHT WILL USHER IN A LOWER CLOUD DECK WITH IFR/LIFR CIGS
BUILDING SOUTHWARD OVER THE REGION AS PER LATEST MOS GUIDANCE. SOME
PATCHY FOG MAY ALSO BE POSSIBLE BUT AT THIS TIME NOT EXPECTING
WIDESPREAD LOWER VISIBILITIES.
RAIN CHANCES WILL INCREASE SLIGHTLY INTO LATE DAY AND TONIGHT WITH
THE FRONT BUT POPS ARE LOW ENOUGH TO KEEP MENTION OUT OF THE TAFS
FOR NOW.
&&
MARINE...
TODAY/TONIGHT...LIGHT TO GENTLE BREEZE EXPECTED TODAY OVER THE
WATERS WITH WINDS INITIALLY OUT OF THE W/SW BECOMING MORE NORTHERLY
AND INCREASING INTO TONIGHT AS A WEAK FRONT MOVES THROUGH THE
REGION.
NORTHERLY SURGE DOES NOT APPEAR AS STRONG AS IT HAD IN PREVIOUS
MODEL RUNS WITH WIND SPEEDS GENERALLY AROUND 15 KNOTS. SEAS BUILDING
TO 6 FEET OVER THE OFFSHORE WATERS NORTH OF THE CAPE BY LATE TONIGHT
STILL LOOKS REASONABLE...SO WILL MAINTAIN THESE WAVE HEIGHTS IN THE
FORECAST.
TUE-FRI...A VERY PROGRESSIVE WEATHER PATTERN WILL LEAD TO QUICKLY
CHANGING WIND FIELDS THROUGH THE PERIOD. A WEAK LOW IS FORECAST
JUST EAST OF THE WATERS TUE WHICH SHOULD PRODUCE A BRIEF PERIOD OF
NORTHERLY WINDS 15-20 KNOTS. THEN ON WED...THE WINDS SHOULD START
OFF LIGHT AND BECOME SOUTHERLY WHILE INCREASING...AS A SURFACE
LOW MOVES TOWARDS NORTH FLORIDA. THE LOW WILL LIFT QUICKLY
NORTHEAST AND SWING A COLD FRONT INTO THE WATERS THU. IN ADDITION
TO INCREASED RAIN CHANCES WED NIGHT AND THU...BREEZY SOUTHERLY
FLOW WILL BECOME NORTHERLY BEHIND THE FRONT THU NIGHT AND CONTINUE
INTO FRI.
&&
.MLB WATCHES/WARNINGS/ADVISORIES...
FL...DENSE FOG ADVISORY UNTIL 10 AM EST THIS MORNING FOR NORTHERN
LAKE COUNTY-SOUTHERN LAKE COUNTY.
AM...NONE.
&&
$$
UPDATE/SHORT TERM...WEITLICH
LONG TERM....LASCODY
AREA FORECAST DISCUSSION
NWS CHARLESTON SC
636 AM EST MON FEB 23 2015
.SYNOPSIS...
A COLD FRONT WILL PUSH ACROSS THE REGION TODAY AND BECOME STATIONARY
SOUTH OF THE AREA TONIGHT. DEVELOPING LOW PRESSURE WILL TRACK ALONG
THE STATIONARY FRONT OVER THE ATLANTIC TUESDAY. HIGH PRESSURE WILL
BRIEFLY BUILD IN TUESDAY NIGHT INTO EARLY WEDNESDAY...FOLLOWED BY
STRONGER LOW PRESSURE FROM THE GULF OF MEXICO THAT PASSES OFFSHORE
WEDNESDAY NIGHT. STRONG HIGH PRESSURE CENTERED NORTH OF THE AREA
WILL EXPAND TO BECOME THE PRIMARY FEATURE LATE WEEK INTO NEXT
WEEKEND.
&&
.NEAR TERM /THROUGH TONIGHT/...
TODAY...SHORTWAVE ENERGY EMBEDDED WITHIN THE NEARLY ZONAL FLOW ALOFT
IS HELPING PROVIDE SOME UPPER SUPPORT FOR LOW LEVEL FORCING ALONG A
COLD FRONT THAT STRETCHES FROM EASTERN NORTH CAROLINA BACK TO THE
LOWER MISSISSIPPI VALLEY. THE RESULT IS A LARGE BAND OF WIDESPREAD
RAINFALL THAT IS IMPACTING MUCH OF THE NORTHERN HALF OF THE FORECAST
AREA THIS MORNING. POPS THROUGH THE REMAINDER OF THE MORNING FEATURE
100 POPS TO THE NORTH...RANGING TO SLIGHT CHANCES FAR TO THE SOUTH
AROUND MCINTOSH COUNTY. THE BEST FORCING WILL REMAIN FOCUSED TO THE
NORTH AND THAT IS WHERE THE HEAVIEST RAIN WILL FALL. THEN FOLLOWING
THE RECENT RUNS OF THE HRRR AND THE RAP...THE BULK OF THE
PRECIPITATION WILL COME TO AN END FROM WEST TO EAST IN THE LATE
MORNING TO EARLY AFTERNOON HOURS. TEMPERATURES ARE CURRENTLY QUITE
MILD ACROSS THE REGION...MAINLY IN THE UPPER 50S AND LOW 60S. THESE
VALUES WILL REMAIN STEADY THROUGH DAYBREAK...AND ONLY BEGIN TO FALL
WITH THE SOUTHWARD PROGRESSION OF THE COLD FRONT. BASED ON THE
TIMING IN THE HRRR AND RAP...THE WIND SHIFT AND ASSOCIATED
INFILTRATION OF COOLER AIR WILL BEGIN TAKING PLACE AROUND 13Z OR SO.
HIGH TEMPERATURES FOR THE DAY WILL OCCUR JUST BEFORE THE FRONT
BEGINS ITS SOUTHWARD MARCH...WITH MID 50S IN MOST AREAS AND EVEN
SOME UPPER 50S AND LOW 60S POSSIBLE FOR SOUTHEAST GEORGIA.
TEMPERATURES WILL THEN STEADILY FALL THROUGH THE DAY.
TONIGHT...THE COLD FRONT WILL BECOME NEARLY STATIONARY TO THE SOUTH
AND SOUTHEAST OF THE REGION AS HIGH PRESSURE BEGINS TO BRIDGE ACROSS
THE OHIO VALLEY AND INTO THE MID ATLANTIC. BY LATE TONIGHT...THE
HIGH WILL SETTLE INTO COLD AIR DAMMING POSITION WITH INCREASINGLY
COOL AIR OOZING IN FROM THE NORTHEAST. EARLY IN THE TONIGHT
PERIOD...THE MODELS GENERALLY SHOW A PRECIPITATION LULL PERIOD AS
THE FORCING ALONG THE FRONT IS DISPLACED TO THE SOUTH AND SOUTHEAST
AND THE UPPER SUPPORT WANES. HOWEVER...BY VERY LATE TONIGHT THE NOSE
OF A 80-90 KT 500 MB JET PUSHES IN FROM THE EAST COINCIDENT WITH AN
AREA OF SHALLOW LOW LEVEL ISENTROPIC LIFT. SOME OF THE MODELS SHOW
PRECIPITATION BREAKING OUT CLOSER TO SUNRISE AT THE SAME TIME AS SUB
FREEZING AIR FILTERS IN FROM THE NORTHEAST. SOUNDINGS SHOW THAT
WHATEVER PRECIPITATION DOES FALL WILL LIKELY FALL AS FREEZING
RAIN/DRIZZLE AND THROUGH THE VERY LATE TONIGHT PERIOD WILL MAINLY
IMPACT THE EXTREME NORTH...ALONG AND NEAR THE SANTEE RIVER. THE BULK
OF THIS EVENT WILL THEN OCCUR INTO TUESDAY MORNING. BY LATE
TONIGHT...LOWS WILL REACH THE LOW 30S FOR MUCH OF SOUTHEAST SOUTH
CAROLINA WITH MID TO UPPER 30S IN SOUTHEAST GEORGIA.
&&
.SHORT TERM /TUESDAY THROUGH THURSDAY/...
TUESDAY...THE STALLED OUT FRONT AND ITS ASSOCIATED BAROCLINIC ZONE
WILL BE FOUND NOT FAR OFF THE SE COAST. CHANNELED VORTICITY ARRIVING
IN THE FAST MOVING AND BROADLY CYCLONIC FLOW ALOFT WILL TRIGGER
CYCLOGENESIS A COUPLE HUNDRED MILES OFF THE NE FLORIDA COAST. AT THE
SAME TIME...UPPER DIVERGENCE/DIFLUENCE ASSOCIATED WITH THE EXIT
REGION OF A ROBUST 130 KT JET AND ISENTROPIC ASCENT ON MAINLY THE
280K AND 285K SURFACES /AROUND 1500-2500 FT/ WILL COMBINE WITH
PRODUCE AN EXPANDING AREA OF RAIN ACROSS THE FORECAST AREA. THERE
STILL REMAINS SOME DISPARITIES BETWEEN THE VARIOUS MODEL
GUIDANCE...BUT WE HAVE LEANED TOWARD A SOLUTION MOST SIMILAR TO A
BLEND OF THE NAM...ECMWF AND CANADIAN MODELS AS OPPOSED TO THE GFS.
COLDER AIR WILL BE FILTERING INTO THE REGION AS A TRANSIENT HIGH
PRESSURE WEDGE DEVELOPS BEHIND THE COLD FRONT STALLED OFFSHORE. THIS
WILL CAUSE A CONCERN FOR THE POTENTIAL FOR FREEZING RAIN AND DRIZZLE
OVER SEVERAL PARTS OF THE FORECAST AREA. SOUNDING DATA REVEALS THAT
THE BEST CHANCE FOR FREEZING SURFACE TEMPS AND/OR WET BULBS WILL
OCCUR MAINLY INLAND FROM US-17 IN SC AND OVER JENKINS AND SCREVEN
COUNTIES IN SE GA. THIS INCLUDES PARTS OF THE CHARLESTON AND
BEAUFORT METRO AREAS...AND IT IS IN THESE LOCATIONS WHERE WE HAVE
GONE AHEAD WITH A FREEZING RAIN ADVISORY FROM 4 AM UNTIL 2 PM
TUESDAY. WHILE IT IS CERTAINLY COLD ENOUGH FOR ICE/SNOW
ALOFT...THERE IS A PRONOUNCED WARM NOSE AROUND 900-750 MB WHICH WILL
TURN WILL ALLOW FOR MELTING OF THE FROZEN PRECIP. BUT THERE IS
ENOUGH MOISTURE AND COLDER AIR BELOW TO ALLOW FOR THE LIQUID DROPS
TO REFREEZE. THERE CAN CERTAINLY BE SOME SLEET MIXED IN...BUT THE
BULK OF THE PRECIP LOOKS TO BE FREEZING RAIN AND/OR DRIZZLE. OUR
CONFIDENCE ON THE AMOUNT OF ICING IS MODERATE AT BEST...SINCE WE
HAVE HAD A SHORT DURATION WARM SPELL AND MUCH OF THE PRECIP MAY TURN
OUT BE RATHER LIGHT IN INTENSITY. THAT SAID...WE DO ANTICIPATE A FEW
HUNDREDTHS OF AN INCH OF FREEZING RAIN ON VARIOUS SURFACES. KEEP IN
MIND THAT THE TALLER BRIDGES OF THE AREA CAN FREEZE BEFORE ROAD
SURFACES. THE DON HOLT BRIDGE IN THE CHARLESTON AREA PROBABLY HAS
THE BEST CHANCE OF EXPERIENCING ANY ICING PROBLEMS TUESDAY
MORNING...BUT WE CAN/T ENTIRELY DISCOUNT THE RAVENEL AND WANDO
BRIDGES ALSO GETTING SOME ICE ON THEM. DEPENDING UPON THE INTENSITY
OF THE PRECIP WE MAY NEED TO EXPAND THE ADVISORY A LITTLE FURTHER
SOUTH INTO GEORGIA AT A LATER TIME. TEMPS LOOK TO BE ABOVE FREEZING
IN THE EARLY TO MID AFTERNOON...THUS ANY FREEZING PRECIP WILL CHANGE
OVER TO LIQUID BEFORE TAPERING OFF LATE.
FOR NOW WE BELIEVE THAT THE PRECIP OVER MUCH OF SE GA...ESPECIALLY
TO THE SOUTH OF I-16 WILL BE ALL OR MAINLY LIQUID WITH QPF/S OF 1/10
TO 1/4 INCH TO OCCUR. TEMPS WON/T GO MUCH OF ANYWHERE...EVEN
DROPPING A COUPLE OF DEGREES DUE TO THE PRECIP...AND WE/LL BE MAINLY
IN THE LOWER AND MIDDLE 30S NORTH/NW TO THE LOWER 40S SOUTH.
TUESDAY NIGHT...THE SURFACE WAVE OVER THE ATLANTIC AND THE
ASSOCIATED FORCING PULL AWAY AS A MESO-HIGH BUILDS FROM THE WEST.
THIS WILL TEMPORARILY SHUT OFF THE PRECIP...AND WE WILL NEED TO
WATCH FOR POSSIBLE RE-FREEZING OF THE EARLIER RAINS...ESPECIALLY OVER
THE CHARLESTON QUAD-COUNTY DISTRICT.
WEDNESDAY AND WEDNESDAY NIGHT...A POTENT SHORT WAVE IN THE DESERT SW
TODAY WILL SHIFT THROUGH THE SOUTHERN PLAINS WEDNESDAY AND HEADS
INTO THE SE AT NIGHT. THIS TRIGGERS SURFACE CYCLOGENESIS IN THE
NORTHERN GULF OF MEXICO BEFORE THE LOW TRACKS JUST OFF THE LOCAL
COASTS BY LATE IN THE PERIOD. LARGE SCALE FORCING FROM THESE
FEATURES AND A POWERFUL WEST-EAST 150 KT UPPER JET WILL ALLOW FOR
CONSIDERABLE OVER-RUNNING RAINS TO DEVELOP BY WEDNESDAY
AFTERNOON...BEFORE TAPERING OFF FROM WEST/SW TO EAST/NE LATE
WEDNESDAY NIGHT. THIS PROMISES TO BE A PRETTY GOOD SOAKER...WITH
PWATS OF 1-1.5 INCHES TO PREVAIL. SOME PLACES COULD EASILY ACHIEVE
THESE AMOUNTS GIVEN THAT WE ARE CARRYING CATEGORICAL POPS. RIGHT
NOW IT LOOKS TO BE ALL LIQUID UNLESS THE OVER-RUNNING RAINS ARRIVE
EARLIER THAN EXPECTED. TEMPS WILL REMAIN FAR BELOW NORMAL.
THURSDAY...MUCH DRIER AIR OVERSPREADS THE REGION BEHIND THE EXITING
SHORT AVE AND SURFACE LOW...LEADING TO A DRY BUT CHILLY DAY WITH
TEMPS AGAIN FAR BELOW SEASONAL NORMS.
&&
.LONG TERM /THURSDAY NIGHT THROUGH SUNDAY/...
A HUMONGOUS AND ROBUST 1040 MB CANADIAN HIGH BUILDING OUT OF THE
GREAT PLAINS WILL EXPAND EAST AND SOUTH AND COVERS MUCH OF THE
NATION EAST OF THE ROCKIES...INCLUDING THE LOCAL AREA. THIS LEADS TO
DRY AND CHILLY CONDITIONS INTO FRIDAY...BEFORE THE HIGH SHIFTS INTO
THE ATLANTIC OVER THE WEEKEND AND EARLY NEXT WEEK AND TEMPS BEGIN TO
MODERATE. A COASTAL TROUGH WILL LIKELY FORM DURING THIS TRANSITION
JUST OFF OUR COAST...AND WE LOOK FOR AT LEAST A SMALL CHANCE OF
SHOWERS IN RESPONSE.
&&
.AVIATION /12Z MONDAY THROUGH FRIDAY/...
KCHS...MVFR OR LOWER CONDITIONS WILL PREVAIL THROUGH 12Z TUESDAY.
LOOKING AT NEARBY OBSERVATIONAL SITES THERE WILL EVEN BE PERIODS
OF IFR OR LOWER WEATHER INTO THIS AFTERNOON. MEANWHILE...A SHORT
WAVE WILL BRUSH THE TERMINAL DURING THE MID MORNING INTO THIS
AFTERNOON...BRINGING WITH IT LIGHT TO PERHAPS RAIN. ALTHOUGH WE
CAN/T RULE OUT A LITTLE DRIZZLE LATE THIS AFTERNOON INTO
TONIGHT...A GREATER RISK FOR DRIZZLE WILL OCCUR CLOSER TO DAYBREAK
TUESDAY. IF IT/S COLD ENOUGH IT MIGHT EVEN BE FREEZING DRIZZLE.
LIGHT WINDS THIS MORNING WILL VEER AROUND TO THE NORTH AND
INCREASE IN WAKE OF A COLD FRONT AROUND 17Z...REMAINING GUSTY
THROUGH THE BALANCE OF THE TAF CYCLE.
KSAV...VFR CONDITIONS THIS MORNING WILL BE SHORT-LIVED AS LOWER
CLOUD DECKS ARRIVE FROM THE NORTH IN RESPONSE TO AN APPROACHING
COLD FRONT. THE FRONT WILL BE ACCOMPANIED BY A LITTLE LIGHT
RAIN...BUT A MORE NOTICEABLE CHANGE WILL BE WINDS BECOMING
NORTH/NE AND GUSTY INTO TONIGHT WITH SUB-VFR WEATHER TO AGAIN
PREVAIL. COULD SEE SOME LIGHT RAINS LATE IN THE PERIOD...BUT A
BETTER CHANCE AFTER 12Z TUESDAY.
EXTENDED AVIATION OUTLOOK...FLIGHT RESTRICTIONS OF VARYING
CATEGORIES WILL CONTINUE MUCH OF THE TIME TUESDAY INTO
THURSDAY...ALTHOUGH INTERLUDES OF VFR ARE POSSIBLE BETWEEN RAIN
EVENTS. ALSO OF NOTE...THERE IS A GOOD CHANCE FOR FREEZING/FROZEN
PRECIPITATION TUESDAY MORNING...ESPECIALLY AT KCHS.
&&
.MARINE...
EARLY MORNING UPDATE...A DENSE FOG ADVISORY HAS BEEN ISSUED FOR
THE CHARLESTON HARBOR AND THE CHARLESTON COUNTY WATERS. THE
CHARLESTON HARBOR PILOT BOAT REPORTED NEAR ZERO VISIBILITY
RECENTLY AND WEB CAMS AROUND DOWNTOWN AND THE HARBOR SHOW A
SHALLOW BANK OF FOG ACROSS THE AREA. THE EXPECTATION IS THAT THERE
IS ALSO DENSE FOG JUST OFFSHORE TOO...THUS THE ADVISORY IS IN
EFFECT. THE FOG SHOULD START TO MIX OUT AND DISSIPATE IN THE LATE
MORNING HOURS/AROUND NOON AS THE COLD FRONT MOVES IN...WINDS PICK
UP AND SHIFT AROUND TO NORTH.
TODAY AND TONIGHT...A COLD FRONT WILL SINK SOUTHWARD
ACROSS THE REGION AND IS EXPECTED TO PUSH ACROSS THE WATERS MAINLY
IN THE AFTERNOON/EVENING HOURS. BEHIND THE FRONT...A SIGNIFICANT
NORTH TO NORTHEAST SURGE IS EXPECTED TO BEGIN WITH RAPIDLY
INCREASING WINDS AND SEAS. WINDS WILL INCREASE FIRST ACROSS THE
CHARLESTON COUNTY WATERS AND THE CHARLESTON HARBOR IN THE EARLY
AFTERNOON...REACHING THE GEORGIA WATERS IN THE LATE AFTERNOON AND
EARLY EVENING HOURS. THE NEARSHORE WATERS WILL SEE WINDS INCREASE
INTO THE 20 TO 25 KT RANGE...INCLUDING THE CHARLESTON HARBOR...WITH
GUSTS TO 30 KT POSSIBLE FOR THE OUTER GEORGIA WATERS. SMALL CRAFT
ADVISORIES ARE IN EFFECT FOR ALL WATERS THROUGH THE OVERNIGHT. THE
NORTH TO NORTHEAST SURGE WILL CONTINUE TONIGHT IN THE WAKE OF THE
FRONT AS THE PRESSURE GRADIENT TIGHTENS ACROSS THE WATERS. WINDS
WILL LIKELY REACH THEIR PEAK IN THE MID TO LATE EVENING HOURS WITH
GUSTS TO 30 KT POSSIBLE ACROSS ALL WATERS. SEAS WILL CONTINUE TO
INCREASE REACHING 4-6 FT WITHIN 20 NM AND 6-9 FT OUT TO 60 NM.
TUESDAY...ONGOING SMALL CRAFT ADVISORIES WILL CONTINUE INTO THE
AFTERNOON IN ASSOCIATION WITH THE GRADIENT BETWEEN THE ATLANTIC LOW
AND A WEAK INLAND HIGH PRESSURE WEDGE. WHILE WE CAN/T RULE OUT A
LITTLE FREEZING RAIN IN CHARLESTON HARBOR...THE BULK OF THE WET
WEATHER LOOKS TO BE IN THE FORM OF LIQUID.
TUESDAY NIGHT INTO WEDNESDAY...CONDITIONS WILL IMPROVE AS THE
ATLANTIC LOW PULLS AWAY AND ANOTHER AREA OF HIGH PRESSURE ARRIVES
FROM THE WEST. WINDS AND SEAS WILL BE FAR BELOW ANY ADVISORY
THRESHOLDS.
LATE WEDNESDAY INTO THURSDAY...CONDITIONS AGAIN WILL DETERIORATE AS
INTENSIFYING LOW PRESSURE DEVELOPS IN THE GULF OF MEXICO AND TRACKS
OVER OR NEAR THE LOCAL WATERS LATE WEDNESDAY NIGHT/EARLY
THURSDAY...BEFORE PULLING AWAY THURSDAY AFTERNOON. SMALL CRAFT
ADVISORIES ARE AGAIN LIKELY AS A RESULT.
FRIDAY THROUGH SATURDAY...A STRENGTHENING REGION OF CONTINENTAL HIGH
PRESSURE WILL OVERSPREAD THE REGION AND GIVEN COLD ADVECTION AND A
TIGHTENING OF THE PRESSURE GRADIENT ADDITIONAL SMALL CRAFT
ADVISORIES ARE ANTICIPATED.
&&
.CHS WATCHES/WARNINGS/ADVISORIES...
GA...FREEZING RAIN ADVISORY FROM 4 AM TO 2 PM EST TUESDAY FOR
GAZ087-088.
SC...FREEZING RAIN ADVISORY FROM 4 AM TO 2 PM EST TUESDAY FOR
SCZ040-042>045-047>050-052.
MARINE...SMALL CRAFT ADVISORY FROM 1 PM THIS AFTERNOON TO 5 PM EST
TUESDAY FOR AMZ352.
DENSE FOG ADVISORY UNTIL NOON EST TODAY FOR AMZ330-350.
SMALL CRAFT ADVISORY FROM 11 AM THIS MORNING TO 5 PM EST
TUESDAY FOR AMZ350.
SMALL CRAFT ADVISORY FROM 2 PM THIS AFTERNOON TO 5 PM EST
TUESDAY FOR AMZ354.
SMALL CRAFT ADVISORY FROM 2 PM THIS AFTERNOON TO 10 PM EST
TUESDAY FOR AMZ374.
SMALL CRAFT ADVISORY FROM 1 PM THIS AFTERNOON TO 2 PM EST
TUESDAY FOR AMZ330.
&&
$$
SYNOPSIS...
NEAR TERM...BSH
SHORT TERM...
LONG TERM...
AVIATION...
MARINE...BSH
AREA FORECAST DISCUSSION
NWS CHARLESTON SC
548 AM EST MON FEB 23 2015
.SYNOPSIS...
A COLD FRONT WILL PUSH ACROSS THE REGION TODAY AND BECOME STATIONARY
SOUTH OF THE AREA TONIGHT. DEVELOPING LOW PRESSURE WILL TRACK ALONG
THE STATIONARY FRONT OVER THE ATLANTIC TUESDAY. HIGH PRESSURE WILL
BRIEFLY BUILD IN TUESDAY NIGHT INTO EARLY WEDNESDAY...FOLLOWED BY
STRONGER LOW PRESSURE FROM THE GULF OF MEXICO THAT PASSES OFFSHORE
WEDNESDAY NIGHT. STRONG HIGH PRESSURE CENTERED NORTH OF THE AREA
WILL EXPAND TO BECOME THE PRIMARY FEATURE LATE WEEK INTO NEXT
WEEKEND.
&&
.NEAR TERM /THROUGH TONIGHT/...
TODAY...SHORTWAVE ENERGY EMBEDDED WITHIN THE NEARLY ZONAL FLOW ALOFT
IS HELPING PROVIDE SOME UPPER SUPPORT FOR LOW LEVEL FORCING ALONG A
COLD FRONT THAT STRETCHES FROM EASTERN NORTH CAROLINA BACK TO THE
LOWER MISSISSIPPI VALLEY. THE RESULT IS A LARGE BAND OF WIDESPREAD
RAINFALL THAT IS IMPACTING MUCH OF THE NORTHERN HALF OF THE FORECAST
AREA THIS MORNING. POPS THROUGH THE REMAINDER OF THE MORNING FEATURE
100 POPS TO THE NORTH...RANGING TO SLIGHT CHANCES FAR TO THE SOUTH
AROUND MCINTOSH COUNTY. THE BEST FORCING WILL REMAIN FOCUSED TO THE
NORTH AND THAT IS WHERE THE HEAVIEST RAIN WILL FALL. THEN FOLLOWING
THE RECENT RUNS OF THE HRRR AND THE RAP...THE BULK OF THE
PRECIPITATION WILL COME TO AN END FROM WEST TO EAST IN THE LATE
MORNING TO EARLY AFTERNOON HOURS. TEMPERATURES ARE CURRENTLY QUITE
MILD ACROSS THE REGION...MAINLY IN THE UPPER 50S AND LOW 60S. THESE
VALUES WILL REMAIN STEADY THROUGH DAYBREAK...AND ONLY BEGIN TO FALL
WITH THE SOUTHWARD PROGRESSION OF THE COLD FRONT. BASED ON THE
TIMING IN THE HRRR AND RAP...THE WIND SHIFT AND ASSOCIATED
INFILTRATION OF COOLER AIR WILL BEGIN TAKING PLACE AROUND 13Z OR SO.
HIGH TEMPERATURES FOR THE DAY WILL OCCUR JUST BEFORE THE FRONT
BEGINS ITS SOUTHWARD MARCH...WITH MID 50S IN MOST AREAS AND EVEN
SOME UPPER 50S AND LOW 60S POSSIBLE FOR SOUTHEAST GEORGIA.
TEMPERATURES WILL THEN STEADILY FALL THROUGH THE DAY.
TONIGHT...THE COLD FRONT WILL BECOME NEARLY STATIONARY TO THE SOUTH
AND SOUTHEAST OF THE REGION AS HIGH PRESSURE BEGINS TO BRIDGE ACROSS
THE OHIO VALLEY AND INTO THE MID ATLANTIC. BY LATE TONIGHT...THE
HIGH WILL SETTLE INTO COLD AIR DAMMING POSITION WITH INCREASINGLY
COOL AIR OOZING IN FROM THE NORTHEAST. EARLY IN THE TONIGHT
PERIOD...THE MODELS GENERALLY SHOW A PRECIPITATION LULL PERIOD AS
THE FORCING ALONG THE FRONT IS DISPLACED TO THE SOUTH AND SOUTHEAST
AND THE UPPER SUPPORT WANES. HOWEVER...BY VERY LATE TONIGHT THE NOSE
OF A 80-90 KT 500 MB JET PUSHES IN FROM THE EAST COINCIDENT WITH AN
AREA OF SHALLOW LOW LEVEL ISENTROPIC LIFT. SOME OF THE MODELS SHOW
PRECIPITATION BREAKING OUT CLOSER TO SUNRISE AT THE SAME TIME AS SUB
FREEZING AIR FILTERS IN FROM THE NORTHEAST. SOUNDINGS SHOW THAT
WHATEVER PRECIPITATION DOES FALL WILL LIKELY FALL AS FREEZING
RAIN/DRIZZLE AND THROUGH THE VERY LATE TONIGHT PERIOD WILL MAINLY
IMPACT THE EXTREME NORTH...ALONG AND NEAR THE SANTEE RIVER. THE BULK
OF THIS EVENT WILL THEN OCCUR INTO TUESDAY MORNING. BY LATE
TONIGHT...LOWS WILL REACH THE LOW 30S FOR MUCH OF SOUTHEAST SOUTH
CAROLINA WITH MID TO UPPER 30S IN SOUTHEAST GEORGIA.
&&
.SHORT TERM /TUESDAY THROUGH THURSDAY/...
TUESDAY...THE STALLED OUT FRONT AND ITS ASSOCIATED BAROCLINIC ZONE
WILL BE FOUND NOT FAR OFF THE SE COAST. CHANNELED VORTICITY ARRIVING
IN THE FAST MOVING AND BROADLY CYCLONIC FLOW ALOFT WILL TRIGGER
CYCLOGENESIS A COUPLE HUNDRED MILES OFF THE NE FLORIDA COAST. AT THE
SAME TIME...UPPER DIVERGENCE/DIFLUENCE ASSOCIATED WITH THE EXIT
REGION OF A ROBUST 130 KT JET AND ISENTROPIC ASCENT ON MAINLY THE
280K AND 285K SURFACES /AROUND 1500-2500 FT/ WILL COMBINE WITH
PRODUCE AN EXPANDING AREA OF RAIN ACROSS THE FORECAST AREA. THERE
STILL REMAINS SOME DISPARITIES BETWEEN THE VARIOUS MODEL
GUIDANCE...BUT WE HAVE LEANED TOWARD A SOLUTION MOST SIMILAR TO A
BLEND OF THE NAM...ECMWF AND CANADIAN MODELS AS OPPOSED TO THE GFS.
COLDER AIR WILL BE FILTERING INTO THE REGION AS A TRANSIENT HIGH
PRESSURE WEDGE DEVELOPS BEHIND THE COLD FRONT STALLED OFFSHORE. THIS
WILL CAUSE A CONCERN FOR THE POTENTIAL FOR FREEZING RAIN AND DRIZZLE
OVER SEVERAL PARTS OF THE FORECAST AREA. SOUNDING DATA REVEALS THAT
THE BEST CHANCE FOR FREEZING SURFACE TEMPS AND/OR WET BULBS WILL
OCCUR MAINLY INLAND FROM US-17 IN SC AND OVER JENKINS AND SCREVEN
COUNTIES IN SE GA. THIS INCLUDES PARTS OF THE CHARLESTON AND
BEAUFORT METRO AREAS...AND IT IS IN THESE LOCATIONS WHERE WE HAVE
GONE AHEAD WITH A FREEZING RAIN ADVISORY FROM 4 AM UNTIL 2 PM
TUESDAY. WHILE IT IS CERTAINLY COLD ENOUGH FOR ICE/SNOW
ALOFT...THERE IS A PRONOUNCED WARM NOSE AROUND 900-750 MB WHICH WILL
TURN WILL ALLOW FOR MELTING OF THE FROZEN PRECIP. BUT THERE IS
ENOUGH MOISTURE AND COLDER AIR BELOW TO ALLOW FOR THE LIQUID DROPS
TO REFREEZE. THERE CAN CERTAINLY BE SOME SLEET MIXED IN...BUT THE
BULK OF THE PRECIP LOOKS TO BE FREEZING RAIN AND/OR DRIZZLE. OUR
CONFIDENCE ON THE AMOUNT OF ICING IS MODERATE AT BEST...SINCE WE
HAVE HAD A SHORT DURATION WARM SPELL AND MUCH OF THE PRECIP MAY TURN
OUT BE RATHER LIGHT IN INTENSITY. THAT SAID...WE DO ANTICIPATE A FEW
HUNDREDTHS OF AN INCH OF FREEZING RAIN ON VARIOUS SURFACES. KEEP IN
MIND THAT THE TALLER BRIDGES OF THE AREA CAN FREEZE BEFORE ROAD
SURFACES. THE DON HOLT BRIDGE IN THE CHARLESTON AREA PROBABLY HAS
THE BEST CHANCE OF EXPERIENCING ANY ICING PROBLEMS TUESDAY
MORNING...BUT WE CAN/T ENTIRELY DISCOUNT THE RAVENEL AND WANDO
BRIDGES ALSO GETTING SOME ICE ON THEM. DEPENDING UPON THE INTENSITY
OF THE PRECIP WE MAY NEED TO EXPAND THE ADVISORY A LITTLE FURTHER
SOUTH INTO GEORGIA AT A LATER TIME. TEMPS LOOK TO BE ABOVE FREEZING
IN THE EARLY TO MID AFTERNOON...THUS ANY FREEZING PRECIP WILL CHANGE
OVER TO LIQUID BEFORE TAPERING OFF LATE.
FOR NOW WE BELIEVE THAT THE PRECIP OVER MUCH OF SE GA...ESPECIALLY
TO THE SOUTH OF I-16 WILL BE ALL OR MAINLY LIQUID WITH QPF/S OF 1/10
TO 1/4 INCH TO OCCUR. TEMPS WON/T GO MUCH OF ANYWHERE...EVEN
DROPPING A COUPLE OF DEGREES DUE TO THE PRECIP...AND WE/LL BE MAINLY
IN THE LOWER AND MIDDLE 30S NORTH/NW TO THE LOWER 40S SOUTH.
TUESDAY NIGHT...THE SURFACE WAVE OVER THE ATLANTIC AND THE
ASSOCIATED FORCING PULL AWAY AS A MESO-HIGH BUILDS FROM THE WEST.
THIS WILL TEMPORARILY SHUT OFF THE PRECIP...AND WE WILL NEED TO
WATCH FOR POSSIBLE RE-FREEZING OF THE EARLIER RAINS...ESPECIALLY OVER
THE CHARLESTON QUAD-COUNTY DISTRICT.
WEDNESDAY AND WEDNESDAY NIGHT...A POTENT SHORT WAVE IN THE DESERT SW
TODAY WILL SHIFT THROUGH THE SOUTHERN PLAINS WEDNESDAY AND HEADS
INTO THE SE AT NIGHT. THIS TRIGGERS SURFACE CYCLOGENESIS IN THE
NORTHERN GULF OF MEXICO BEFORE THE LOW TRACKS JUST OFF THE LOCAL
COASTS BY LATE IN THE PERIOD. LARGE SCALE FORCING FROM THESE
FEATURES AND A POWERFUL WEST-EAST 150 KT UPPER JET WILL ALLOW FOR
CONSIDERABLE OVER-RUNNING RAINS TO DEVELOP BY WEDNESDAY
AFTERNOON...BEFORE TAPERING OFF FROM WEST/SW TO EAST/NE LATE
WEDNESDAY NIGHT. THIS PROMISES TO BE A PRETTY GOOD SOAKER...WITH
PWATS OF 1-1.5 INCHES TO PREVAIL. SOME PLACES COULD EASILY ACHIEVE
THESE AMOUNTS GIVEN THAT WE ARE CARRYING CATEGORICAL POPS. RIGHT
NOW IT LOOKS TO BE ALL LIQUID UNLESS THE OVER-RUNNING RAINS ARRIVE
EARLIER THAN EXPECTED. TEMPS WILL REMAIN FAR BELOW NORMAL.
THURSDAY...MUCH DRIER AIR OVERSPREADS THE REGION BEHIND THE EXITING
SHORT AVE AND SURFACE LOW...LEADING TO A DRY BUT CHILLY DAY WITH
TEMPS AGAIN FAR BELOW SEASONAL NORMS.
&&
.LONG TERM /THURSDAY NIGHT THROUGH SUNDAY/...
A HUMONGOUS AND ROBUST 1040 MB CANADIAN HIGH BUILDING OUT OF THE
GREAT PLAINS WILL EXPAND EAST AND SOUTH AND COVERS MUCH OF THE
NATION EAST OF THE ROCKIES...INCLUDING THE LOCAL AREA. THIS LEADS TO
DRY AND CHILLY CONDITIONS INTO FRIDAY...BEFORE THE HIGH SHIFTS INTO
THE ATLANTIC OVER THE WEEKEND AND EARLY NEXT WEEK AND TEMPS BEGIN TO
MODERATE. A COASTAL TROUGH WILL LIKELY FORM DURING THIS TRANSITION
JUST OFF OUR COAST...AND WE LOOK FOR AT LEAST A SMALL CHANCE OF
SHOWERS IN RESPONSE.
&&
.AVIATION /12Z MONDAY THROUGH FRIDAY/...
ONGOING VFR CONDITIONS AT KCHS AND KSAV WILL ONLY LAST A FEW MORE
HOURS AS RAINFALL AND LOWERING CEILINGS BEGIN TO IMPACT THE
TERMINALS. AT KCHS...RAINFALL WILL BECOME STEADY AND PERIODICALLY
MODERATE IN INTENSITY. CEILINGS ARE EXPECTED TO FALL TO MVFR BY
08Z...THOUGH VISIBILITIES IN RAIN COULD BE MVFR OR TEMPORARILY IFR
AT TIMES. CEILINGS WILL CONTINUE TO STEADILY FALL AND REACH IFR
LEVELS AROUND 10Z. THE PRECIPITATION WILL COME TO AN END AROUND
16Z AND THEN LITTLE TO NO RAIN IS EXPECTED THROUGH THE END OF THE
FORECAST. IFR CEILINGS WILL STICK THROUGH THE DAY...LIFTING TO
MVFR IN THE LATE EVENING HOURS. THE MAIN WIND SHIFT WITH THE FRONT
WILL TAKE PLACE AROUND NOON AND WINDS THEREAFTER WILL INCREASE AND
BECOME NORTHERLY. AT KSAV...RAINFALL CHANCES ARE MUCH LOWER AND
THE OVERALL TIMING OF LOWERING CEILINGS WILL BE ABOUT 2-3 HOURS
LATER THAN KCHS. SIMILARLY...IFR CEILINGS WILL SETTLE IN BY LATE
MORNING AND REMAIN THROUGH THE DAY. THE WIND SHIFT WITH THE FRONT
WILL ARRIVE AT KSAV IN THE EARLY AFTERNOON. AN IMPROVEMENT TO MVFR
SHOULD TAKE PLACE CLOSER TO MIDNIGHT.
EXTENDED AVIATION OUTLOOK...FLIGHT RESTRICTIONS OF VARYING
CATEGORIES WILL CONTINUE MUCH OF THE TIME MONDAY NIGHT INTO
THURSDAY...ALTHOUGH INTERLUDES OF VFR ARE POSSIBLE BETWEEN RAIN
EVENTS. ALSO OF NOTE...THERE IS A SLIGHT CHANCE FOR FREEZING/FROZEN
PRECIPITATION LATE MONDAY NIGHT INTO TUESDAY MORNING.
&&
.MARINE...
EARLY MORNING UPDATE...A DENSE FOG ADVISORY HAS BEEN ISSUED FOR
THE CHARLESTON HARBOR AND THE CHARLESTON COUNTY WATERS. THE
CHARLESTON HARBOR PILOT BOAT REPORTED NEAR ZERO VISIBILITY
RECENTLY AND WEB CAMS AROUND DOWNTOWN AND THE HARBOR SHOW A
SHALLOW BANK OF FOG ACROSS THE AREA. THE EXPECTATION IS THAT THERE
IS ALSO DENSE FOG JUST OFFSHORE TOO...THUS THE ADVISORY IS IN
EFFECT. THE FOG SHOULD START TO MIX OUT AND DISSIPATE IN THE LATE
MORNING HOURS/AROUND NOON AS THE COLD FRONT MOVES IN...WINDS PICK
UP AND SHIFT AROUND TO NORTH.
TODAY AND TONIGHT...A COLD FRONT WILL SINK SOUTHWARD
ACROSS THE REGION AND IS EXPECTED TO PUSH ACROSS THE WATERS MAINLY
IN THE AFTERNOON/EVENING HOURS. BEHIND THE FRONT...A SIGNIFICANT
NORTH TO NORTHEAST SURGE IS EXPECTED TO BEGIN WITH RAPIDLY
INCREASING WINDS AND SEAS. WINDS WILL INCREASE FIRST ACROSS THE
CHARLESTON COUNTY WATERS AND THE CHARLESTON HARBOR IN THE EARLY
AFTERNOON...REACHING THE GEORGIA WATERS IN THE LATE AFTERNOON AND
EARLY EVENING HOURS. THE NEARSHORE WATERS WILL SEE WINDS INCREASE
INTO THE 20 TO 25 KT RANGE...INCLUDING THE CHARLESTON HARBOR...WITH
GUSTS TO 30 KT POSSIBLE FOR THE OUTER GEORGIA WATERS. SMALL CRAFT
ADVISORIES ARE IN EFFECT FOR ALL WATERS THROUGH THE OVERNIGHT. THE
NORTH TO NORTHEAST SURGE WILL CONTINUE TONIGHT IN THE WAKE OF THE
FRONT AS THE PRESSURE GRADIENT TIGHTENS ACROSS THE WATERS. WINDS
WILL LIKELY REACH THEIR PEAK IN THE MID TO LATE EVENING HOURS WITH
GUSTS TO 30 KT POSSIBLE ACROSS ALL WATERS. SEAS WILL CONTINUE TO
INCREASE REACHING 4-6 FT WITHIN 20 NM AND 6-9 FT OUT TO 60 NM.
TUESDAY...ONGOING SMALL CRAFT ADVISORIES WILL CONTINUE INTO THE
AFTERNOON IN ASSOCIATION WITH THE GRADIENT BETWEEN THE ATLANTIC LOW
AND A WEAK INLAND HIGH PRESSURE WEDGE. WHILE WE CAN/T RULE OUT A
LITTLE FREEZING RAIN IN CHARLESTON HARBOR...THE BULK OF THE WET
WEATHER LOOKS TO BE IN THE FORM OF LIQUID.
TUESDAY NIGHT INTO WEDNESDAY...CONDITIONS WILL IMPROVE AS THE
ATLANTIC LOW PULLS AWAY AND ANOTHER AREA OF HIGH PRESSURE ARRIVES
FROM THE WEST. WINDS AND SEAS WILL BE FAR BELOW ANY ADVISORY
THRESHOLDS.
LATE WEDNESDAY INTO THURSDAY...CONDITIONS AGAIN WILL DETERIORATE AS
INTENSIFYING LOW PRESSURE DEVELOPS IN THE GULF OF MEXICO AND TRACKS
OVER OR NEAR THE LOCAL WATERS LATE WEDNESDAY NIGHT/EARLY
THURSDAY...BEFORE PULLING AWAY THURSDAY AFTERNOON. SMALL CRAFT
ADVISORIES ARE AGAIN LIKELY AS A RESULT.
FRIDAY THROUGH SATURDAY...A STRENGTHENING REGION OF CONTINENTAL HIGH
PRESSURE WILL OVERSPREAD THE REGION AND GIVEN COLD ADVECTION AND A
TIGHTENING OF THE PRESSURE GRADIENT ADDITIONAL SMALL CRAFT
ADVISORIES ARE ANTICIPATED.
&&
.CHS WATCHES/WARNINGS/ADVISORIES...
GA...FREEZING RAIN ADVISORY FROM 4 AM TO 2 PM EST TUESDAY FOR
GAZ087-088.
SC...FREEZING RAIN ADVISORY FROM 4 AM TO 2 PM EST TUESDAY FOR
SCZ040-042>045-047>050-052.
MARINE...SMALL CRAFT ADVISORY FROM 1 PM THIS AFTERNOON TO 5 PM EST
TUESDAY FOR AMZ352.
DENSE FOG ADVISORY UNTIL NOON EST TODAY FOR AMZ330-350.
SMALL CRAFT ADVISORY FROM 11 AM THIS MORNING TO 5 PM EST
TUESDAY FOR AMZ350.
SMALL CRAFT ADVISORY FROM 2 PM THIS AFTERNOON TO 5 PM EST
TUESDAY FOR AMZ354.
SMALL CRAFT ADVISORY FROM 2 PM THIS AFTERNOON TO 10 PM EST
TUESDAY FOR AMZ374.
SMALL CRAFT ADVISORY FROM 1 PM THIS AFTERNOON TO 2 PM EST
TUESDAY FOR AMZ330.
&&
$$
NEAR TERM...BSH
SHORT TERM...
LONG TERM...
AVIATION...BSH
MARINE...BSH
AREA FORECAST DISCUSSION
NWS CARIBOU ME
934 AM EST MON FEB 23 2015
.SYNOPSIS...
A STRONG COLD FRONT WILL CROSS THE AREA THIS MORNING. HIGH
PRESSURE WILL BUILD ACROSS NORTHERN NEW ENGLAND TONIGHT AND WILL
MOVE EAST TUESDAY. DEVELOPING LOW PRESSURE FROM THE WEST WILL
CROSS THE AREA WEDNESDAY THEN MOVE TOWARD THE NORTHERN MARITIMES
WEDNESDAY NIGHT.
&&
.NEAR TERM /THROUGH TONIGHT/...
930 AM UPDATE...LATEST RADAR SHOWED AREA OF SNOW AND SQUALLS NOW
IN NEW BRUNSWICK. BTV SNOW SQUALL PARAMETER AND 06Z NAM DID A FINE
JOB IN PICKING UP THE SNOW SQUALLS AS THEY MOVED THROUGH THE
REGION EARLIER THIS MORNING. THE HRRR MODEL AND THE RAP APPEAR TO
BE IN STEP W/TEH CURRENT SET PER THE RADAR IMAGERY. A FEW AREAS OF
SNOW STILL OCCURRING ACROSS THE REGION. ONE WAS ACROSS AR NORTHERN
MAINE NEAR THE FRENCHVILLE REGION COMING OFF ST. LAWRENCE
RIVER(STREAMER). THE OTHER AREA WAS MOVING OFF THE MT. KATAHDIN
REGION MOVING ACROSS SE AROOSTOOK COUNTY AND NORTHERN WASHINGTON
COUNTY. ADDED A 1/2 INCH OF NEW SNOW TO ACCOUNT FOR THESE AREAS OF
SNOW. VISIBLE SATELLITE IMAGERY SHOWED PLENTY OF SUNSHINE W/
SCATTERED STRATOCUMULUS. THE SUN COMBINED W/THE CAA TAKING PLACE
AIDING IN THE INCREASED WINDS. ADDED AREAS OF BLOWING SNOW TO THE
FORECAST FOR THIS AFTERNOON. WILL ADD BLOWING SNOW TO THE WSW
COMBINED W/THE WIND CHILL ADVISORY NW WINDS 15-25 MPH SUSTAINED
W/GUSTS TO 35 MPH EXPECTED.
PREVIOUS DISCUSSION...HIGH TEMPERATURES WILL BE EARLY THIS
MORNING, ESPECIALLY IN THE NORTH, THEN TEMPERATURES WILL FALL
THROUGH MUCH OF THE DAY UNDER BRISK WEST WINDS. WIND CHILLS WILL
QUICKLY DROP TO -15F TO -30F THIS AFTERNOON AND EVENING, SO HAVE
CONTINUED WITH THE WIND CHILL ADVISORY FOR OUR ENTIRE FORECAST
AREA. MUCH OF THE MODEL GUIDANCE CONTINUES TO INDICATE THE
POTENTIAL FOR SNOW SQUALLS AND/OR STREAMERS COMING OFF THE SAINT
LAWRENCE OVER FAR NORTHERN AROOSTOOK COUNTY THROUGH MUCH OF THE
DAY. AREAS OF BLOWING AND DRIFTING SNOW ARE ALSO A CONCERN ACROSS
ALL OF NORTHERN AND CENTRAL MAINE, AS THE GUSTY WINDS WILL EASILY
LOFT THE RECENTLY- FALLEN SNOW. ROAD CONDITIONS WILL LIKELY BE
POOR IN OPEN TERRAIN WITH SNOW DRIFTS AND VISIBILITY SHARPLY
REDUCED TO NEAR ZERO AT TIMES, ESPECIALLY ALONG NORTH-SOUTH ROADS
SUCH AS ROUTES 1 AND 11.
FOR TONIGHT...THE ARCTIC HIGH WILL BUILD INTO NEW ENGLAND OVERNIGHT.
TEMPERATURES WILL PLUMMET THROUGH THE EVENING, WITH LOWS -15F TO -25F
ACROSS THE NORTHERN HALF OF OUR FORECAST AREA. DOWNEAST AREAS WILL
EVEN DROP BELOW ZERO, WITH LOWS OF -5F TO -15F. WINDS WILL
GRADUALLY ABATE LATER TONIGHT IN RESPONSE TO THE WEAKENING
PRESSURE GRADIENT UNDER THE RIDGE, ESPECIALLY OVER FAR WESTERN
LOCATIONS. THEREFORE, IN SPITE OF THE VERY COLD AIR TEMPERATURES,
THE WIND CHILL ADVISORY STILL LOOKS APPLICABLE, AS OPPOSED TO A
WIND CHILL WARNING.
&&
.SHORT TERM /TUESDAY THROUGH WEDNESDAY/...
THE CORE OF BITTERLY COLD ARCTIC AIR WILL BE MOVG E OF THE FA TUE
MORN. AFT A VERY COLD START TO THE DAY...HI TEMPS SHOULD RECOVER
INTO THE SINGLE DIGITS BY MID TO LATE AFTN...WITH DOWNEAST AREAS
RECOVERING INTO THE TEENS BY ERLY EVE AS SFC WINDS BECOME SRLY
COMPONENT BEHIND DEPARTING SFC HI PRES MOVG E TOWARD THE OPEN
ATLC. THIS RETURN FLOW WILL BRING INCREASING CLDNSS FROM S TO N
ACROSS THE REGION TUE NGT...WITH LGT SN POSSIBLE TO PTNS OF THE FA
LATE TUE NGT.
MODELS THEN SHOW A S/WV COMPLEX MOVG E FROM CNTRL CAN AND THE
GREAT LKS TUE NGT INTO WED. THE SFC LOW WITH THIS SYSTEM IS XPCTD
TO REFORM FROM QB TUE NGT TO A SECONDARY LOW OVR THE S GULF OF ME
SW OF NOVA SCOTIA. THE SECONDARY LOW THEN GAINS MOMENTUM WED
AFTN...ABSORBING THE OLD PRIMARY LOW FROM QB BY WED EVE. A POCKET
OF SRLY LOW TO MID LVL WARM/MOISTURE ADVCN BEGINS TO DEVELOP OVR
ERN ME BEGINNING ERLY WED MORN JUST AHEAD OF THE DEVELOPING
SECONDARY...RESULTING IN MORE ORGANIZED SNFL CLIPPING ERN ME
MON MORN INTO ERLY AFTN BEFORE MOVING ENE INTO NB BY LATE WED
AFTN. MODELS VARY WITH REGARD TO THE QPF THAT MAY OCCUR OVR ERN
ME WITH THE TMG OF THIS EVENT...WITH THE 00Z DTMNSTC CANGEM AND
NAM MOST AGGRESSIVE AND THE GFS AND SPCLY ECMWF THE LEAST. WPC IS
LEANING MORE WITH THE GFS AND ECMWF MODELS ATTM...SO WE WEIGHT
THESE MODELS MORE WITH FCST 6HRLY QPF AND CORRESPONDING SNFL LATE
TUE NGT THRU WED. CONSIDERING THE UNCERTAINTY OF TMG OF
DEVELOPMENT OF THE SNFL SHIELD BEFORE THE SECONDARY MOVES AWAY
FROM THE REGION...WE KEPT SN TO LIQ RATIOS RELATIVELY CONSERVATIVE
AT 13.5 TO 1...WHICH RESULTS IN MAX TOTALS OF 3 TO 4 INCHES OVR SE
WASHINGTON COUNTY WHERE WE GO WITH CATEGORICAL POPS WITH LESSER
AMOUNTS AND POPS TO THE WNW.
SN SHOULD TAPER TO SN SHWRS FROM W TO E ACROSS THE REGION FROM
MID AFTN TO ERLY EVE...THEN END FROM S TO N OVRNGT WED...WITH
STRONGER LLVL COLD ADVCN XPCTD LATE WED NGT AND ERLY THU MORN WITH
A SECONDARY ARCTIC COLD FRONT.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/...
ANOTHER DEEP ARCTIC AIR MASS WILL FOLLOW THE SECONDARY COLD FRONT
ACROSS THE REGION FROM CNTRL CAN...WITH THIS AIR MASS NOT QUITE AS
COLD AS THE PRIOR AIR MASS AFFECTING THE FA ON TUE. UNDER FAIR
SKIES...HI TEMPS WILL BE WELL BLO SEASONAL AVGS FOR THE END OF FEB
THU AND FRI...WITH SOME RADIATIONAL COOLING POSSIBLE THU NGT AND
MSLY FRI NGT AS LARGE SPRAWLING SFC HI PRES RIDGES ENE INTO THE
REGION. WITH WEAK PRES GRAD FLOW INDICATED...THE BEST POTENTIAL
FOR COLDEST OVRNGT LOWS WILL BE ACROSS BROAD RVR VLYS OF NRN AND
CNTRL PTNS OF THE FA...WITH HILL TOP LCTNS LIKELY MAINTAINING A
LGT BREEZE KEEP OVRNGT LOWS NOT AS COLD. ANOTHER WV OF LOW PRES
TRACKING OFF THE SE U.S COAST WILL KEEP A LITTLE MORE PRES GRAD
AND PERHAPS HI CLD OVR THE DOWNEAST COAST BOTH NGTS LMTG THE
POTENTIAL OF VERY COLD LOW TEMPS.
SAT SHOULD CONT FAIR...BUT NOT AS COLD AS FCST AFTN 925 MB TEMPS
RISE FROM THE LOWER TO MID -20S TO -10S DEG C. WITH THE CNTR OF
STRONG SFC HI PRES TRACKING WELL S OF THE FA AS IT MOVES OFF THE
MID ATLC COAST...WINDS WILL LIKELY NOT HAVE MUCH CHC TO DECOUPLE
EVEN OVR VLY AREAS SAT NGT. SUN WILL BEGIN FAIR...THEN HI/MID
CLDNSS INCREASE LATER IN THE DAY AS A LARGE SHIELD OF LGT OVRRNG
SNFL APCHS FROM THE GREAT LKS AND QB PROV BY SUN EVE.
&&
.AVIATION /15Z MONDAY THROUGH FRIDAY/...
NEAR TERM: MVFR CONDITIONS WITH OCCASIONAL IFR IN LIGHT SNOW AT
KHUL/KBHB WILL LINGER THROUGH 14Z OR SO TODAY. THEN CONDITIONS
WILL GRADUALLY IMPROVE AS A COLD FRONT CROSSES THE AREA AND ALLOWS
COLDER AND DRIER AIR TO SPREAD OVER THE REGION. WEST WINDS WILL
INCREASE TO 10-15KT WITH GUSTS TO 25KT POSSIBLE. THIS MAY RESULT
IN BLOWING SNOW WHICH COULD REDUCE VISIBILITY TO IFR AT TIMES
THROUGH THIS EVENING. OTHERWISE, PREVAILING VFR CONDITIONS ARE
EXPECTED FROM 15Z SOUTH/21Z NORTH WITH CLEARING SKIES.
SHORT TO LONG TERM: VFR XPCTD ALL TAF SITES TUE THRU TUE
EVE...WITH MVFR CLGS POSSIBLE LATE TUE NGT AND THEN MVFR OR IFR
VSBYS WITH LGT SNFL DURING THE DAY WED. AFTWRDS...MVFR CLGS CONT
ACROSS NRN TAF SITES WED NGT INTO THU MORN WHILE DOWNEAST SITES
BECOME VFR. ALL SITES THEN BECOME VFR THU AFTN AND CONT SO THRU
FRI.
&&
.MARINE...
NEAR TERM: A GALE WARNING REMAINS IN PLACE FOR TODAY AND TONIGHT.
A COLD FRONT WILL CROSS THE WATERS THIS MORNING, FOLLOWED BY WEST
TO NORTHWEST WINDS OF 20 TO 30 KT WITH GUSTS IN EXCESS OF 35 KT.
BITTERLY COLD TEMPERATURES AND THE STRONG WINDS WILL COMBINE TO
CREATE HEAVY FREEZING SPRAY, ESPECIALLY OVER THE OUTER WATERS, SO
THE FREEZING SPRAY WARNING REMAINS IN PLACE FOR LATER TODAY
THROUGH TONIGHT.
SHORT TO LONG TERM: SCA OR LESS CONDITIONS XPCTD THRU THIS PTN OF
THE FCST. HVY FZGSPY SHOULD BECOME MDT BY 12Z TUE...BECOMING LGT
BY LATE DAY AND THEN ENDING BY WED MORN AS COLD ADVCN DIMINISHES
OVR THE WATERS AND EVENTUALLY REVERSES TO WARM ADVCN. WENT ABV WW3
GUIDANCE FOR FCST WV HTS BY A FACTOR OF 1.15 OR SO...BASED ON BIAS
TRENDS OBSVD OVR THE PAST FEW WEEKS.
&&
.CAR WATCHES/WARNINGS/ADVISORIES...
ME...WIND CHILL ADVISORY FROM 3 PM THIS AFTERNOON TO 10 AM EST
TUESDAY FOR MEZ001>006-010-011-031-032.
WIND CHILL ADVISORY FROM 7 PM THIS EVENING TO 7 AM EST TUESDAY
FOR MEZ015>017-029-030.
MARINE...HEAVY FREEZING SPRAY WARNING FROM 3 PM THIS AFTERNOON TO 7 AM
EST TUESDAY FOR ANZ050>052.
GALE WARNING UNTIL 4 AM EST TUESDAY FOR ANZ050>052.
&&
$$
NEAR TERM...HASTINGS/HEWITT
SHORT TERM...VJN
LONG TERM...VJN
AVIATION...HASTINGS/HEWITT/VJN
MARINE...HASTINGS/HEWITT/VJN
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
637 AM EST MON FEB 23 2015
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 532 AM EST MON FEB 23 2015
WV IMAGERY AND RUC ANALYSIS INDICATED A PROMINENT RIDGE FROM THE ERN
PACIFIC INTO BC AND MID LEVEL LOW NEAR JAMES BAY RESULTING IN NNW
FLOW FROM NRN CANADA INTO THE WRN GREAT LAKES. A VIGOROUS UPSTREAM
SHORTWAVE TROUGH WAS LOCATED OVER NRN CANADA. AT THE SFC...LIGHT
WRLY FLOW PREVAILED ACROSS THE REGION AS ARCTIC HIGH PRES SLOWLY
BUILDS TO THE SE TO WRN IA. WITH THE EXTENSIVE ICE COVER ACROSS LAKE
SUPERIOR...RADAR/SATELLITE INDICATED ONLY MINIMAL/WEAK LES TO NEAR
MUNISING AND GRAND MARAIS THAT WAS SLOWLY LIFTING OFFSHORE AS WINDS
BACK. EARLY MORNING TEMPS GENERALLY RANGING BETWEEN -10F TO -20F
ALONG WITH WINDS AROUND 5 MPH PRODUCED WIND CHILLS IN THE -20 TO -35
RANGE.
TODAY...WIND CHILL VALUES WILL ONLY SLOWLY MODERATE THIS MORNING AS
TEMPS CLIMBING BACK TOWARD ZERO WILL BE OFFSET BY INCREASING SW
WINDS TO AROUND 10 MPH. OTHERWISE...QUIET WEATHER IS EXPECTED WITH
GRADUALLY INCREASING MID AND HIGH CLOUDS IN THE WAA PATTERN BETWEEN
THE RETREATING HIGH AND THE CLIPPER LOW MOVING SSE FROM CANADA. THE
TIGHTENING PRES GRADIENT WILL BRING GUSTY WINDS BY LATE TODAY MAKING
IT STILL FEEL VERY COLD EVEN AS TEMPS CLIMB TO HIGHS NEAR 10F.
TONIGHT...THE NRN CANADA SHRTWV WILL QUICKLY DIVE TO THE SSE TO THE
NORTH SHORE OF LAKE SUPERIOR BY 12Z/TUE. THE WAA AND PATTERN AND
280K ISENTROPIC LIFT AHEAD OF THE TROUGH WILL BRING WIDESREAD LIGHT
SNOW TO THE REGION. EXPECT A DELAY TO THE ONSET OF SNOW TIL LATE
EVENING AND OVERNIGHT GIVEN THE VERY DRY AIRMASS IN PLACE OVER THE
REGION AND THE TIME TO SATURATE THE 925-700 MB LAYER...PER FCST
SOUNDINGS. POTENTIAL SNOWFALL AMOUNTS OF A HALF INCH TO AROUND 2
INCHES ARE CONSISTENT WITH 1.0-1.5 G/KG AVAILABLE DURING THE PERIOD
OF STRONGER LIFT AND QPF BETWEEN 0.03-0.08 WITH SLR VALUES AROUND
20/1. THE GREATEST AMOUNTS ARE EXPECTED FROM THE KEWEENAW INTO THE
ERN CWA WHERE THE FCST LIFT AND A LONGER PERIOD OF SATURATION IS
FCST. POTENTIAL FOR LAKE ENHANCEMENT WITH SW FLOW OFF OF SOME
REMAINING OPEN WATER IN NRN LAKE MI SHOULD REMAIN MAINLY EAST OF THE
CWA...PER HIGHER RES MODELS 230-250 FCST LOW LEVEL FLOW DIRECTION.
.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 250 AM EST MON FEB 23 2015
TUESDAY THROUGH SUNDAY WILL BE MARKED BY BOOKEND LOW PRESSURE
SYSTEMS...WITH HIGH PRESSURE IN BETWEEN. THE FIRST AT 12Z TUESDAY
WILL BE SET UP FROM S HUDSON BAY THROUGH CENTRAL ONTARIO...AND
CENTRAL LAKE SUPERIOR...DRAGGING A COLD FRONT ACROSS THE W THIRD OF
THE CWA. THE FRONTAL BOUNDARY WILL SWIFTLY EXIT E...AND RESIDE FROM
JAMES BAY THRUOGH FAR SE LAKE SUPERIOR BY 18Z TUESDAY. 1-2 IN OF NEW
SNOW WILL BE POSSIBLE TUESDAY OVER MUCH OF THE CWA...WITH THE
HIGHEST VALUES FAR N AND E. WHILE WINDS ALOFT WILL BE DIMINISHING
FROM THE 40-50KT WINDS OVERNIGHT...SFC WINDS WILL BE STEADY TO ON
THE INCREASE. LOOK FOR WINDS OF 10-20KTS DURING THE DAY
TUESDAY...HIGHEST W AND ALONG LAKE SUPERIOR.
WILL BE INTERESTING TO SEE WHAT THE INCREASED SW WINDS TODAY-
TONIGHT...AND NW WINDS TUESDAY DO TO THE RELATIVLY THIN AND
FRACTURED ICE COVERING MUCH OF LAKE SUPERIOR. HOW IT PROGRESSES WILL
HAVE A LARGE IMPACT ON THE AREAL COVERAGE AND INTENSITY OF LAKE
EFFECT SNOW BANDS TUESDAY AFTERNOON THROUGH THURSDAY ON MAINLY NW TO
WNW WINDS.
SLOWLY FALLING INVERSION HEIGHTS TUESDAY NIGHT...AND THE DGZ GOING
AWAY AS MUCH COLDER AIR SLIDES IN ON THE NW WINDS WILL RESULT IN THE
RETURN OF SMALL SNOWFLAKES THAT WILL NOT ACCUMULATE TO MUCH BUT ARE
VERY AFFECTIVE AT REDUCING VIS. ANOTHER COLD ARCTIC ARIMASS WILL BE
ABLE TO SLIDE INTO THE REGION AS HIGH PRESSURE OVER MUCH OF THE W
HALF OF CANADA SLOWLY SINKS ACROSS S CENTRAL CANADA...THE N AND
CENTRAL PLAINS...AND THE UPPER GREAT LAKES BY THE END OF THE WORK
WEEK. LIGHT LES ON N TO WNW WINDS WILL BE THE RULE.
WIND CHILL VALUES WILL AGAIN FALL INTO THE -20 TO -30F RANGE LATE
TUESDAY NIGHT THROUGH WEDNESDAY MORNING. THAT 10MPH WIND PORTION OF
THE WIND CHILL ADVISORY SHOULD BE MET ACROSS MOST OF THE CWA...WITH
STRONGER NW WINDS NEARING 15MPH N CENTRAL AND E ALONG LAKE SUPERIOR.
THE APPARENT TEMPERATURE PORTION OF WIND CHILL ADVISORY CRITERIA IS
-25 TO -34F.
LATE WEDNESDAY NIGHT INTO EARLY THURSDAY MORNING MAY AGAIN BRING US
DOWN TO 20 TO NEAR 30 BELOW ZERO WIND CHILLS. HOWEVER...THE NW WINDS
SHOULD BE MUCH LIGHTER.
THURSDAY NIGHT-FRIDAY WILL BE A PERIOD OF MAINLY W TO WSW WINDS.
LAKE EFFECT SNOW SHOWERS SHOULD BE EITHER MIMIMAL OR NON-
EXISTANT...AND IMPACTING THE KEWEENAW PENINSULA AND RIGHT ALONG THE
LAKE SUPERIOR SHORELINE AROUND AND E OF GRAND MARAIS.
EXPECT DRY WEATHER SATURDAY...BUT INCREASING SW WINDS AND INVADING
CLOUDS FROM THE W. 850MB TEMPS WILL RISE TO AROUND -11 TO -13C
SATURDAY AND SUNDAY. SFC TEMPERATURES SHOULD REBOUND TO NEAR
20F...WHICH IS STILL AROUND 10 DEGREES BELOW NORMAL FOR THIS TIME OF
YEAR. SUNDAY SHOULD BE A COUPLE DEGREES WARMER...BUT FILLED WITH
MORE CLOUDS AND SNOW FOR THE ENTIRE CWA. EARLY INDICATIONS FROM THE
GFS POINT TO 2-5IN OF SNOW CWA WIDE LATE SATURDAY AFTERNOON THROUGH
SUNDAY EVENING. THE BEST MOISTURE LOOKS TO REMAIN TO OUR S AS UPPER
MI IS IN BETWEEN 2 LOWS /ONE OVER HUDSON BAY...AND ANOTHER EJECTING
OUT OF THE CENTRAL PLAINS/.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z TUESDAY MORNING)
ISSUED AT 637 AM EST MON FEB 23 2015
AFTER A PERIOD OF MVFR CIGS EARLY AT KMCX FROM LIMITED MOISTENING
FROM UPSTREAM GAPS IN THE ICE COVER ON LAKE SUPERIOR...A STEADY WNW
SLOWLY BACKING SW FLOW OF DRY AIR TO THE N OF HIGH PRES MOVING INTO
THE OH RIVER VALLEY WILL RESULT IN VFR CONDITIONS AT ALL 3 TAF SITES
INTO THIS EVENING. THE SW WINDS WILL STRENGTHEN AND TURN GUSTY THIS
AFTERNOON AS THE PRES GRADIENT TIGHTENS AHEAD OF A COLD FRONT
APPROACHING FROM THE NW. SNOW IN ADVANCE OF THIS FRONT WILL ARRIVE
FROM NW TO SE LATE THIS EVENING. THE DRY NATURE OF THE ANTECEDENT
AIRMASS WILL MAINTAIN VFR CONDITIONS INITIALLY DESPITE THE
THICKENING CLOUDD COVER. HOWEVER...CONDITIONS WILL DROP TO MVFR AFT
06Z AND LIKELY TO IFR AT CMX WHERE THE HEAVIER SNOW IS EXPECTED.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 532 AM EST MON FEB 23 2015
SOUTHWEST WINDS WILL QUICKLY INCREASE THIS AFTERNOON BETWEEN LOW
PRESSURE DROPPING SOUTHEAST THROUGH NORTHERN ONTARIO AND HIGH PRES
MOVING INTO THE OH VALLEY. THIS WILL LEAD TO SOUTHWESTERLY GALES OF
35-40KTS OVER PORTIONS OF LAKE SUPERIOR THIS AFTERNOON AND EVENING.
A GALE WARNING REMAINS IN EFFECT FOR MUCH OF WESTERN/CENTRAL LAKE
SUPERIOR FOR LATE THIS AFTERNOON AND TONIGHT. THEN AS A COLD FRONT
SLIDES SOUTHEAST ACROSS LAKE SUPERIOR LATE TONIGHT INTO TUESDAY
MORNING AND SHIFT WINDS TO THE NORTHWEST...THERE MAY BE A FEW GALE
FORCE GUSTS TO 35 KNOTS BEHIND THE FRONT ON TUESDAY OVER EASTERN
LAKE SUPERIOR. A HIGH PRESSURE RIDGE WILL BUILD BACK INTO THE AREA
WEDNESDAY AND REMAIN INTO FRIDAY...LEADING TO GENERALLY LIGHT WINDS
BELOW 20KTS.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
WIND CHILL ADVISORY UNTIL NOON EST /11 AM CST/ TODAY FOR
MIZ001>007-009>014-084-085.
LAKE SUPERIOR...
GALE WARNING FROM 7 PM THIS EVENING TO 7 AM EST TUESDAY FOR
LSZ266.
GALE WARNING FROM 4 PM EST /3 PM CST/ THIS AFTERNOON TO 7 AM EST
/6 AM CST/ TUESDAY FOR LSZ162-263-264.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...JLB
LONG TERM...KF
AVIATION...JLB
MARINE...JLB
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
532 AM EST MON FEB 23 2015
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 532 AM EST MON FEB 23 2015
WV IMAGERY AND RUC ANALYSIS INDICATED A PROMINENT RIDGE FROM THE ERN
PACIFIC INTO BC AND MID LEVEL LOW NEAR JAMES BAY RESULTING IN NNW
FLOW FROM NRN CANADA INTO THE WRN GREAT LAKES. A VIGOROUS UPSTREAM
SHORTWAVE TROUGH WAS LOCATED OVER NRN CANADA. AT THE SFC...LIGHT
WRLY FLOW PREVAILED ACROSS THE REGION AS ARCTIC HIGH PRES SLOWLY
BUILDS TO THE SE TO WRN IA. WITH THE EXTENSIVE ICE COVER ACROSS LAKE
SUPERIOR...RADAR/SATELLITE INDICATED ONLY MINIMAL/WEAK LES TO NEAR
MUNISING AND GRAND MARAIS THAT WAS SLOWLY LIFTING OFFSHORE AS WINDS
BACK. EARLY MORNING TEMPS GENERALLY RANGING BETWEEN -10F TO -20F
ALONG WITH WINDS AROUND 5 MPH PRODUCED WIND CHILLS IN THE -20 TO -35
RANGE.
TODAY...WIND CHILL VALUES WILL ONLY SLOWLY MODERATE THIS MORNING AS
TEMPS CLIMBING BACK TOWARD ZERO WILL BE OFFSET BY INCREASING SW
WINDS TO AROUND 10 MPH. OTHERWISE...QUIET WEATHER IS EXPECTED WITH
GRADUALLY INCREASING MID AND HIGH CLOUDS IN THE WAA PATTERN BETWEEN
THE RETREATING HIGH AND THE CLIPPER LOW MOVING SSE FROM CANADA. THE
TIGHTENING PRES GRADIENT WILL BRING GUSTY WINDS BY LATE TODAY MAKING
IT STILL FEEL VERY COLD EVEN AS TEMPS CLIMB TO HIGHS NEAR 10F.
TONIGHT...THE NRN CANADA SHRTWV WILL QUICKLY DIVE TO THE SSE TO THE
NORTH SHORE OF LAKE SUPERIOR BY 12Z/TUE. THE WAA AND PATTERN AND
280K ISENTROPIC LIFT AHEAD OF THE TROUGH WILL BRING WIDESREAD LIGHT
SNOW TO THE REGION. EXPECT A DELAY TO THE ONSET OF SNOW TIL LATE
EVENING AND OVERNIGHT GIVEN THE VERY DRY AIRMASS IN PLACE OVER THE
REGION AND THE TIME TO SATURATE THE 925-700 MB LAYER...PER FCST
SOUNDINGS. POTENTIAL SNOWFALL AMOUNTS OF A HALF INCH TO AROUND 2
INCHES ARE CONSISTENT WITH 1.0-1.5 G/KG AVAILABLE DURING THE PERIOD
OF STRONGER LIFT AND QPF BETWEEN 0.03-0.08 WITH SLR VALUES AROUND
20/1. THE GREATEST AMOUNTS ARE EXPECTED FROM THE KEWEENAW INTO THE
ERN CWA WHERE THE FCST LIFT AND A LONGER PERIOD OF SATURATION IS
FCST. POTENTIAL FOR LAKE ENHANCEMENT WITH SW FLOW OFF OF SOME
REMAINING OPEN WATER IN NRN LAKE MI SHOULD REMAIN MAINLY EAST OF THE
CWA...PER HIGHER RES MODELS 230-250 FCST LOW LEVEL FLOW DIRECTION.
.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 250 AM EST MON FEB 23 2015
TUESDAY THROUGH SUNDAY WILL BE MARKED BY BOOKEND LOW PRESSURE
SYSTEMS...WITH HIGH PRESSURE IN BETWEEN. THE FIRST AT 12Z TUESDAY
WILL BE SET UP FROM S HUDSON BAY THROUGH CENTRAL ONTARIO...AND
CENTRAL LAKE SUPERIOR...DRAGGING A COLD FRONT ACROSS THE W THIRD OF
THE CWA. THE FRONTAL BOUNDARY WILL SWIFTLY EXIT E...AND RESIDE FROM
JAMES BAY THRUOGH FAR SE LAKE SUPERIOR BY 18Z TUESDAY. 1-2 IN OF NEW
SNOW WILL BE POSSIBLE TUESDAY OVER MUCH OF THE CWA...WITH THE
HIGHEST VALUES FAR N AND E. WHILE WINDS ALOFT WILL BE DIMINISHING
FROM THE 40-50KT WINDS OVERNIGHT...SFC WINDS WILL BE STEADY TO ON
THE INCREASE. LOOK FOR WINDS OF 10-20KTS DURING THE DAY
TUESDAY...HIGHEST W AND ALONG LAKE SUPERIOR.
WILL BE INTERESTING TO SEE WHAT THE INCREASED SW WINDS TODAY-
TONIGHT...AND NW WINDS TUESDAY DO TO THE RELATIVLY THIN AND
FRACTURED ICE COVERING MUCH OF LAKE SUPERIOR. HOW IT PROGRESSES WILL
HAVE A LARGE IMPACT ON THE AREAL COVERAGE AND INTENSITY OF LAKE
EFFECT SNOW BANDS TUESDAY AFTERNOON THROUGH THURSDAY ON MAINLY NW TO
WNW WINDS.
SLOWLY FALLING INVERSION HEIGHTS TUESDAY NIGHT...AND THE DGZ GOING
AWAY AS MUCH COLDER AIR SLIDES IN ON THE NW WINDS WILL RESULT IN THE
RETURN OF SMALL SNOWFLAKES THAT WILL NOT ACCUMULATE TO MUCH BUT ARE
VERY AFFECTIVE AT REDUCING VIS. ANOTHER COLD ARCTIC ARIMASS WILL BE
ABLE TO SLIDE INTO THE REGION AS HIGH PRESSURE OVER MUCH OF THE W
HALF OF CANADA SLOWLY SINKS ACROSS S CENTRAL CANADA...THE N AND
CENTRAL PLAINS...AND THE UPPER GREAT LAKES BY THE END OF THE WORK
WEEK. LIGHT LES ON N TO WNW WINDS WILL BE THE RULE.
WIND CHILL VALUES WILL AGAIN FALL INTO THE -20 TO -30F RANGE LATE
TUESDAY NIGHT THROUGH WEDNESDAY MORNING. THAT 10MPH WIND PORTION OF
THE WIND CHILL ADVISORY SHOULD BE MET ACROSS MOST OF THE CWA...WITH
STRONGER NW WINDS NEARING 15MPH N CENTRAL AND E ALONG LAKE SUPERIOR.
THE APPARENT TEMPERATURE PORTION OF WIND CHILL ADVISORY CRITERIA IS
-25 TO -34F.
LATE WEDNESDAY NIGHT INTO EARLY THURSDAY MORNING MAY AGAIN BRING US
DOWN TO 20 TO NEAR 30 BELOW ZERO WIND CHILLS. HOWEVER...THE NW WINDS
SHOULD BE MUCH LIGHTER.
THURSDAY NIGHT-FRIDAY WILL BE A PERIOD OF MAINLY W TO WSW WINDS.
LAKE EFFECT SNOW SHOWERS SHOULD BE EITHER MIMIMAL OR NON-
EXISTANT...AND IMPACTING THE KEWEENAW PENINSULA AND RIGHT ALONG THE
LAKE SUPERIOR SHORELINE AROUND AND E OF GRAND MARAIS.
EXPECT DRY WEATHER SATURDAY...BUT INCREASING SW WINDS AND INVADING
CLOUDS FROM THE W. 850MB TEMPS WILL RISE TO AROUND -11 TO -13C
SATURDAY AND SUNDAY. SFC TEMPERATURES SHOULD REBOUND TO NEAR
20F...WHICH IS STILL AROUND 10 DEGREES BELOW NORMAL FOR THIS TIME OF
YEAR. SUNDAY SHOULD BE A COUPLE DEGREES WARMER...BUT FILLED WITH
MORE CLOUDS AND SNOW FOR THE ENTIRE CWA. EARLY INDICATIONS FROM THE
GFS POINT TO 2-5IN OF SNOW CWA WIDE LATE SATURDAY AFTERNOON THROUGH
SUNDAY EVENING. THE BEST MOISTURE LOOKS TO REMAIN TO OUR S AS UPPER
MI IS IN BETWEEN 2 LOWS /ONE OVER HUDSON BAY...AND ANOTHER EJECTING
OUT OF THE CENTRAL PLAINS/.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT)
ISSUED AT 1220 AM EST MON FEB 23 2015
A STEADY WNW SLOWLY BACKING SW FLOW OF DRY AIR TO THE N OF HI PRES
MOVING INTO THE OH RIVER VALLEY WL RESULT IN VFR CONDITIONS AT ALL 3
TAF SITES INTO THIS EVNG. ALTHOUGH THE W WIND WL UPSLOPE INTO CMX
EARLY THIS MRNG...THE UPSTREAM AIRMASS IS SO DRY AND LK SUP
SUFFICIENTLY ICE COVERED TO LIMIT THE POTENTIAL FOR LES OR EVEN MUCH
IN THE WAY OF LK CLDS. THE SW WINDS WL STRENGTHEN AND TURN GUSTY
THIS AFTN AS THE PRES GRADIENT TIGHTENS AHEAD OF A COLD FNT APRCHG
FM THE NW. SN IN ADVANCE OF THIS FNT WL ARRIVE NW-SE LATE THIS EVNG.
DRY NATURE OF THE ANTECEDENT AIRMASS WL MAINTAIN VFR CONDITIONS
INITIALLY DESPITE THE THICKENING CLD COVER AND ARRIVING -SN. BEST
CHC FOR MVFR CONDITIONS BEFORE 24/06Z WL BE AT CMX...WHERE THE PCPN
WL ARRIVE EARLIEST.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 532 AM EST MON FEB 23 2015
SOUTHWEST WINDS WILL QUICKLY INCREASE THIS AFTERNOON BETWEEN LOW
PRESSURE DROPPING SOUTHEAST THROUGH NORTHERN ONTARIO AND HIGH PRES
MOVING INTO THE OH VALLEY. THIS WILL LEAD TO SOUTHWESTERLY GALES OF
35-40KTS OVER PORTIONS OF LAKE SUPERIOR THIS AFTERNOON AND EVENING.
A GALE WARNING REMAINS IN EFFECT FOR MUCH OF WESTERN/CENTRAL LAKE
SUPERIOR FOR LATE THIS AFTERNOON AND TONIGHT. THEN AS A COLD FRONT
SLIDES SOUTHEAST ACROSS LAKE SUPERIOR LATE TONIGHT INTO TUESDAY
MORNING AND SHIFT WINDS TO THE NORTHWEST...THERE MAY BE A FEW GALE
FORCE GUSTS TO 35 KNOTS BEHIND THE FRONT ON TUESDAY OVER EASTERN
LAKE SUPERIOR. A HIGH PRESSURE RIDGE WILL BUILD BACK INTO THE AREA
WEDNESDAY AND REMAIN INTO FRIDAY...LEADING TO GENERALLY LIGHT WINDS
BELOW 20KTS.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
WIND CHILL ADVISORY UNTIL NOON EST /11 AM CST/ TODAY FOR
MIZ001>007-009>014-084-085.
LAKE SUPERIOR...
GALE WARNING FROM 7 PM THIS EVENING TO 7 AM EST TUESDAY FOR
LSZ266.
GALE WARNING FROM 4 PM EST /3 PM CST/ THIS AFTERNOON TO 7 AM EST
/6 AM CST/ TUESDAY FOR LSZ162-263-264.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...JLB
LONG TERM...KF
AVIATION...KC
MARINE...JLB
AREA FORECAST DISCUSSION
NWS RALEIGH NC
1015 AM EST MON FEB 23 2015
.SYNOPSIS..AN AREA OF LOW PRESSURE AND ATTENDANT COLD FRONT WILL PUSH
SOUTH AND EAST OF THE AREA LATER THIS MORNING. ARCTIC HIGH
PRESSURE WILL BUILD INTO OUR AREA THIS AFTERNOON THROUGH TUESDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 1015 AM MONDAY...
A LOW AMPLITUDE SHORTWAVE AND ASSOCIATED WEAK SURFACE LOW ARE
DEPARTING THE SC COAST THIS MORNING. ANAFRONTAL PRECIP MAINLY
SOUTHEAST OF THE TRIANGLE AREA WILL ALSO CONTINUE TO EXIT TO THE
EAST THROUGH EARLY AFTERNOON. WEAK COLD ADVECTION WILL PERSIST THIS
AFTERNOON BEFORE THE STRONGER SURGE OCCURS THIS EVENING AHEAD THE
ARCTIC HIGH BUILDING ACROSS THE CENTRAL APPALACHIANS. DUE TO THE
DELAYED ARRIVAL OF COLDER LOW-LEVEL AIR...THE WETBULB FREEZING LINE
IS STILL WELL TO OUR NORTH IN CENTRAL VA AND BY THE TIME IT SINKS
SOUTH IN THE NORTHERN COASTAL PLAIN THIS AFTERNOON... ALL DEEPER
MOISTURE AND PRECIP WILL EITHER HAVE DEPARTED OR PRECIP WON`T BE OF
SUFFICIENT INTENSITY TO CAUSE WETBULBING OR ANY WINTRY IMPACTS.
LATEST GUIDANCE REFLECTS THIS. WILL KEEP THE GENERAL TREND OF POPS
GOING AND JUST MAKE SOME ALTERATIONS TO ACCOUNT FOR LATEST
RADAR....WITH POPS ENDING AFTER 18Z. WILL ALSO HAVE AN EYE ON THE
POTENTIAL FOR A MESOSCALE BAND OF SHALLOW MOISTURE AND PRECIP (MOST
LIKELY SLEET BASED ON TEMPS AROUND -10C IN THE SHALLOW SATURATED
LAYER) IN THE 21Z TO 03Z TIME FRAME...THOUGH NO IMPACT WOULD BE
EXPECTED AT THIS TIME. HI-RES MODELS ARE STILL SPLIT ON WHETHER OR
NOT THIS WILL DEVELOP...BUT MODELS HAVE BEEN SHOWING SOMETHING OF
THIS NATURE FOR MULTIPLE RUNS.
REGARDING TEMPS...THICKNESSES WILL STEADILY FALL THROUGHOUT THE DAY
IN THE NORTHEAST FLOW...SO FOR MANY LOCATIONS HIGHS IN THE UPPER 30S
NORTH TO MID 40S SOUTH HAVE ALREADY OCCURRED. THE HRRR SHOWS SOME
INTERMITTENT BREAKS IN CLOUDS OVER THE THE NORTHWEST PIEDMONT WITH
WESTERLY FLOW ALOFT AND NOT AS MUCH LOW-LEVEL MOISTURE THERE. NOT
CONFIDENT IN THE UPPER 40S THE HRRR GIVES...BUT THERE COULD BE A
LITTLE WARMING THROUGH EARLY AFTERNOON.
TONIGHT: THE SECOND BATCH OF S/W ENERGY MOVES INTO THE AREA BETWEEN
06 TO 12Z TUESDAY. RESULTANT WEAK DPVA AND SHALLOW ISENTROPIC
UPGLIDE WILL RE-NEW/DEEPEN SATURATION ALOFT TO SUPPORT SOME LIGHT
SNOW AND FLURRIES INTO THE AREA AROUND DAYBREAK ACROSS THE WESTERN
AND SOUTHERN PORTIONS OF THE FORECAST AREA. MODELS ARE ONLY
GENERATING A HUNDREDTH OR TWO ACROSS THE AREA SO NO ACCUMULATION ARE
EXPECTED. CAA WILL GOVERN LOWS TONIGHT...RANGING FROM UPPER TEENS
ACROSS THE NE TO MID 20S SOUTH.
&&
.SHORT TERM /TUESDAY AND TUESDAY NIGHT/...
AS OF 330 AM MONDAY...
TRANSITORY ARCTIC HIGH PRESSURE WILL HAVE SETTLED ACROSS THE HEART
OF CENTRAL NC BY TUESDAY MORNING. THIS HIGH PRESSURE WILL BE NUDGED
OFFSHORE BY LATE DAY AS A FAST MOVING SHORT WAVE MOVES EAST ACROSS
THE AREA. BRIEF SOUTHERLY FLOW AND WEAK SUPPORT ALOFT WILL
POTENTIALLY PRODUCE SOME LIGHT SNOW/FLURRIES...MAINLY ACROSS THE
SOUTHERN TIER AND THE WESTERN PIEDMONT TUESDAY MORNING THROUGH
AROUND MID DAY. OTHERWISE...SKIES WILL REMAIN BE MOSTLY CLOUDY
THROUGH THE DAY WITH HIGHS PEAKING IN THE MID TO UPPER 30S. MINOR
MODERATION IN MIN TEMPS IS EXPECTED TUE NIGHT WITH DOWNSLOPE WARMING
IN GENERALLY WESTERLY LOW LEVEL FLOW AIDED BY STREAMING MID TO HIGH
CLOUDINESS ALOFT IN THE FAST CONFLUENT FLOW. MINS WILL BE MOSTLY IN
THE MID 20S.
&&
.LONG TERM /WEDNESDAY THROUGH SUNDAY/...
AS OF 330 AM MONDAY...
A SOUTHERN STREAM SHORT WAVE MOVING ACROSS THE SOUTHEASTERN GULF
STATES HAS BEEN ADVERTISED FOR THE MIDWEEK FOR THE PAST FEW DAYS.
THIS SHORT WAVE WILL INDUCE CYCLOGENESIS ALONG THE SOUTHERN STREAM
MOISTURE PLUME/STALLED FRONTAL ZONE. THE RESULTING LOW WILL MOVE
NORTHEAST ACROSS NORTHERN FLORIDA AND GRAZE THE AREA AS IT MOVES OFF
INTO THE MID ATLANTIC. RAIN WILL SPREAD INTO THE SOUTHERN TIER AS
EARLY AS WEDNESDAY AFTERNOON...WITH BETTER CHANCES DURING THE
OVERNIGHT. COLD AIR WILL BE SURGING SOUTH BEHIND THE LOW...AND
EXPECT A SOUTHERLY TRANSITION TO SNOW OVERNIGHT AS MINS FALL INTO
THE MID AND UPPER 20S. A CHANCE OF SNOW WILL LINGER INTO THURSDAY
MORNING EAST OF INTERSTATE 95...OTHERWISE SKIES WILL REMAIN CLOUDY
WITH HIGHS SUFFERING ANOTHER SETBACK AS REINFORCING HIGH PRESSURE
AGAIN SETTLES DOWN THE COAST. THURSDAYS HIGHS WILL BE IN THE UPPER
30S NORTH TO LOWER 40S SOUTH.
HAVE LITTLE CONFIDENCE IN NAILING DOWN THE FEATURES OF POTENTIAL
PRECIP PRODUCING SYSTEMS AS THE WEEKEND APPROACHES IN THIS STUBBORN
SPLIT FLOW REGIME...I.E. EVOLUTION AND TIMING OF NORTHERN VS
SOUTHERN STREAM FEATURES AND THEIR REFUSAL TO COME INTO PHASE.
CONFIDENCE IS HIGH THAT HIGHS FRIDAY THROUGH SUNDAY WILL REMAIN
WELL BELOW NORMAL...GENERALLY IN THE UPPER 30S TO LOWER 40S FRIDAY
AND SATURDAY...AND LOW AMPLITUDE RIDGING LATE THIS WEEKEND WILL
PRODUCE A WARMUP SUNDAY...WITH PERHAPS NEAR NORMAL HIGHS ON MONDAY.
&&
.AVIATION /06Z MONDAY THROUGH FRIDAY/...
AS OF 620 AM MONDAY...
24HR TAF PERIOD: UPPER LEVEL DISTURBANCES TRACKING THROUGH THE
SOUTHEAST US THIS MORNING WILL SUPPORT WEAK ISENTROPIC LIFT AS A
WEAK AREA OF LOW PRESSURE DEVELOPS ALONG THE SOUTHWARD SINKING COLD
FRONT. THE STEADIER...MORE WIDESPREAD RAIN WILL TRACK ACROSS THE SE
PORTIONS OF THE AREA AND WILL AFFECT KFAY THROUGH 15Z-17Z. RDU AND
RWI WILL SEE SOME LIGHT PATCHY RAIN DURING THE SAME PERIOD...WHILE
KGSO AND KINT WILL LIKELY REMAIN DRY. CIGS ARE EXPECTED TO GENERALLY
RANGE FROM MVFR NW TO POSSIBLY IFR/LIFR SOUTHEAST. STRONG CAA DURING
THE DAY WILL RESULT IN NELY WIND GUSTS OF 20 TO 25KTS STRONGEST AT
KFAY. ADDITIONALLY...COULD SEE A BRIEF CHANGEOVER TO SNOW OR SLEET
THIS AFTERNOON AS COLD AIR BUILDS INTO THE AREA FROM THE NORTH.
LOW-LEVEL DRY AIR FEED SHOULD ALLOW CIGS TO LIFT TO VFR AT KGSO/KINT
BY THE AFTERNOON... WITH KRDU/KFAY/KRWI DELAYED UNTIL THE EVENING.
SUB-VFR CONDITIONS COULD SPREAD BACK INTO THE KINT AND KGSO BETWEEN
06 TO 12Z TUESDAY AS ANOTHER BATCH OF UPPER DISTURBANCES MOVES INTO
THE REGION ALONG WITH SNOW FLURRIES.
OUTLOOK: COULD SEE A PERIOD OF IFR TO MVFR CONDITIONS WITH FLURRIES
ON TUESDAY AS ANOTHER UPPER LEVEL DISTURBANCE TRACKS THROUGH THE
REGION. AN AREA OF LOW PRESSURE TRACKING NE FROM THE GULF OF MEXICO
TO THE SOUTHEAST COAST MAY SPREAD PRECIPITATION WITH ADVERSE
AVIATION CONDITIONS INTO THE AREA WEDNESDAY NIGHT INTO THURSDAY.
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...CBL/BLS
NEAR TERM...CBL/BLS
SHORT TERM...MLM
LONG TERM...MLM
AVIATION...CBL
AREA FORECAST DISCUSSION
NWS TULSA OK
539 AM CST MON FEB 23 2015
.AVIATION...
CONCERNING TAF SITES KTUL/KRVS/KBVO/KMLC/KXNA/KFYV/KFSM/KROG.
WIDESPREAD LIGHT SNOW WILL TRACK ACROSS NE OK / FAR NW AR WITH
MINIMAL FLIGHT IMPACTS EXPECTED. MORE WIDESPREAD AND PROLONGED
AVIATION IMPACTS ARE EXPECTED ACROSS SE OK INTO WEST CENTRAL
ARKANSAS W/ MVFR TO IFR CONDITIONS LIKELY. PRECIP WILL DIMINISH BY
EARLY EVENING WITH A TREND TOWARD VFR / MVFR CEILINGS.
&&
.PREV DISCUSSION... /ISSUED 406 AM CST MON FEB 23 2015/
DISCUSSION...
ANOTHER ROUND OF WINTER WEATHER IS ABOUT TO GET UNDERWAY ACROSS
PARTS OF EASTERN OK EARLY THIS MORNING. A LARGE AREA OF SHOWERY
PRECIP HAS SPREAD ACROSS WESTERN/CENTRAL OK A LITTLE AHEAD OF
SCHEDULE...WITH SEVERAL REPORTS OF GRAUPEL OR ICE PELLETS DESPITE
ALL MODEL SOUNDINGS POINTING TO SNOW. STILL BELIEVE THIS WILL
MAINLY BE A SNOW EVENT FOR ALL BUT FAR SOUTHERN OK BUT THE
CONVECTIVE NATURE OF AT LEAST THIS EARLY ROUND OF PRECIP LENDS SOME
CONFIDENCE TO ADDING A SLEET/SNOW MIXTURE NORTH TO ABOUT I-40 THIS
MORNING. OVERALL CONFIGURATION AND TIMING OF ADVISORY APPEARS GOOD
FOR NOW...THOUGH MUCH OF THE EVENT MAY BE DONE WELL BEFORE 00Z
EXPIRATION TIME. LATEST RUNS OF HRRR HAVE ALSO SPREAD HEAVIER SNOW
TOTALS A BIT FARTHER NORTH ACROSS EASTERN OK AND THIS WILL NEED TO
BE WATCHED THROUGHOUT THE DAY. TEMPS TODAY WILL NOT GO MUCH OF
ANYWHERE WITH MOSTLY LOW/MID 20S FOR HIGHS.
COLD AND DRY TONIGHT WITH A MODEST WARM UP ON TUESDAY...WHICH WILL
FEEL NICE AFTER LAST COUPLE OF DAYS DESPITE BEING SEVERAL DEGREES
BELOW NORMAL. UPPER LEVEL SYSTEM OVER THE SOUTHWEST WILL MOVE EAST
ACROSS TEXAS TUE NIGHT INTO WED...WITH A SMALL CHANCE OF PRECIP
SPREADING INTO SE OKLAHOMA DURING THAT TIME IN THE FORM OF LIGHT
SNOW OR SLEET. THIS IS NOT EXPECTED TO BE MUCH OF AN ISSUE AS THE
HEAVIER PRECIP SHOULD STAY SOUTH OF THE RED RIVER. A NICE WARM UP
FOR WEDNESDAY BUT NOT FOR LONG AS ANOTHER SURGE OF MUCH COLDER AIR
PLUNGES SOUTH BY THURSDAY.
HIGH LEVELS OF UNCERTAINTY IN THE EXTENDED FORECAST BUT IT DOES
APPEAR THAT TEMPS WILL WARM UP BY NEXT WEEKEND...ENOUGH FOR ANY
PRECIP TO BE LIQUID. THERE STILL MAY BE A TRANSITION PERIOD LATE
IN THE WEEK HOWEVER SO WINTER WEATHER POTENTIAL WILL STILL BE
PRESENT FOR THU INTO SAT. FORECAST CONFIDENCE REMAINS QUITE LOW
BEYOND THURSDAY.
&&
.PRELIMINARY POINT TEMPS/POPS...
TUL 25 17 43 25 / 30 10 10 10
FSM 29 23 42 26 / 60 20 10 10
MLC 27 17 40 26 / 70 20 10 10
BVO 24 14 44 20 / 20 10 10 10
FYV 24 17 40 21 / 30 10 10 10
BYV 23 18 39 24 / 20 10 10 10
MKO 26 20 42 24 / 40 10 10 10
MIO 25 16 40 23 / 20 10 10 10
F10 25 19 42 26 / 60 10 10 10
HHW 29 22 37 28 / 80 20 10 20
&&
.TSA WATCHES/WARNINGS/ADVISORIES...
OK...WINTER WEATHER ADVISORY UNTIL 6 PM MONDAY FOR OKZ049-OKZ053-
OKZ065-OKZ066-OKZ070-OKZ071-OKZ072-OKZ073-OKZ074-OKZ075-
OKZ076.
AR...WINTER WEATHER ADVISORY UNTIL 6 PM MONDAY FOR ARZ019-ARZ020-
ARZ029.
&&
$$
AVIATION...07
AREA FORECAST DISCUSSION
NWS TULSA OK
406 AM CST MON FEB 23 2015
.DISCUSSION...
ANOTHER ROUND OF WINTER WEATHER IS ABOUT TO GET UNDERWAY ACROSS
PARTS OF EASTERN OK EARLY THIS MORNING. A LARGE AREA OF SHOWERY
PRECIP HAS SPREAD ACROSS WESTERN/CENTRAL OK A LITTLE AHEAD OF
SCHEDULE...WITH SEVERAL REPORTS OF GRAUPEL OR ICE PELLETS DESPITE
ALL MODEL SOUNDINGS POINTING TO SNOW. STILL BELIEVE THIS WILL
MAINLY BE A SNOW EVENT FOR ALL BUT FAR SOUTHERN OK BUT THE
CONVECTIVE NATURE OF AT LEAST THIS EARLY ROUND OF PRECIP LENDS SOME
CONFIDENCE TO ADDING A SLEET/SNOW MIXTURE NORTH TO ABOUT I-40 THIS
MORNING. OVERALL CONFIGURATION AND TIMING OF ADVISORY APPEARS GOOD
FOR NOW...THOUGH MUCH OF THE EVENT MAY BE DONE WELL BEFORE 00Z
EXPIRATION TIME. LATEST RUNS OF HRRR HAVE ALSO SPREAD HEAVIER SNOW
TOTALS A BIT FARTHER NORTH ACROSS EASTERN OK AND THIS WILL NEED TO
BE WATCHED THROUGHOUT THE DAY. TEMPS TODAY WILL NOT GO MUCH OF
ANYWHERE WITH MOSTLY LOW/MID 20S FOR HIGHS.
COLD AND DRY TONIGHT WITH A MODEST WARM UP ON TUESDAY...WHICH WILL
FEEL NICE AFTER LAST COUPLE OF DAYS DESPITE BEING SEVERAL DEGREES
BELOW NORMAL. UPPER LEVEL SYSTEM OVER THE SOUTHWEST WILL MOVE EAST
ACROSS TEXAS TUE NIGHT INTO WED...WITH A SMALL CHANCE OF PRECIP
SPREADING INTO SE OKLAHOMA DURING THAT TIME IN THE FORM OF LIGHT
SNOW OR SLEET. THIS IS NOT EXPECTED TO BE MUCH OF AN ISSUE AS THE
HEAVIER PRECIP SHOULD STAY SOUTH OF THE RED RIVER. A NICE WARM UP
FOR WEDNESDAY BUT NOT FOR LONG AS ANOTHER SURGE OF MUCH COLDER AIR
PLUNGES SOUTH BY THURSDAY.
HIGH LEVELS OF UNCERTAINTY IN THE EXTENDED FORECAST BUT IT DOES
APPEAR THAT TEMPS WILL WARM UP BY NEXT WEEKEND...ENOUGH FOR ANY
PRECIP TO BE LIQUID. THERE STILL MAY BE A TRANSITION PERIOD LATE
IN THE WEEK HOWEVER SO WINTER WEATHER POTENTIAL WILL STILL BE
PRESENT FOR THU INTO SAT. FORECAST CONFIDENCE REMAINS QUITE LOW
BEYOND THURSDAY.
&&
.PRELIMINARY POINT TEMPS/POPS...
TUL 25 17 43 25 / 30 10 10 10
FSM 29 23 42 26 / 60 20 10 10
MLC 27 17 40 26 / 70 20 10 10
BVO 24 14 44 20 / 20 10 10 10
FYV 24 17 40 21 / 30 10 10 10
BYV 23 18 39 24 / 20 10 10 10
MKO 26 20 42 24 / 40 10 10 10
MIO 25 16 40 23 / 20 10 10 10
F10 25 19 42 26 / 60 10 10 10
HHW 29 22 37 28 / 80 20 10 20
&&
.TSA WATCHES/WARNINGS/ADVISORIES...
OK...WINTER WEATHER ADVISORY UNTIL 6 PM MONDAY FOR OKZ049-OKZ053-
OKZ065-OKZ066-OKZ070-OKZ071-OKZ072-OKZ073-OKZ074-OKZ075-
OKZ076.
AR...WINTER WEATHER ADVISORY UNTIL 6 PM MONDAY FOR ARZ019-ARZ020-
ARZ029.
&&
$$
SHORT TERM...07
LONG TERM....14
AREA FORECAST DISCUSSION
NWS AUSTIN/SAN ANTONIO TX
530 AM CST MON FEB 23 2015
.AVIATION UPDATE...FOR 12Z TAF PACKAGE...
CURRENT CONDITIONS WILL LIKELY PERSIST THROUGH ENTIRE TAF PERIOD.
THERE IS SOME CONCERN FOR -FZDZ THIS MORNING FOR KAUS SO INCLUDED
TEMPO GROUP TO HANDLE THAT. OTHERWISE -DZ EXPECTED FOR ALL
TERMINALS TODAY. AS PREVIOUS FORECAST MENTIONED...ICING WILL BE A
CONCERN FOR THE LOWEST 3KFT JUST OFF THE SURFACE DURING TAKEOFF AND
LANDING FOR ALL TERMINALS. OTHERWISE...MVFR/IFR CEILINGS ARE
EXPECTED THROUGHOUT THE DAY AND NIGHT. GUSTY WINDS WILL ALSO
PERSIST THROUGH THE DAY.
&&
.PREV DISCUSSION... /ISSUED 457 AM CST MON FEB 23 2015/
SHORT TERM (TODAY THROUGH TUESDAY)...
EARLY MORNING OBSERVATIONS SHOW THE FREEZING LINE ROUGHLY ALONG A
GEORGETOWN TO BOERNE TO COMSTOCK LINE. OBSERVATIONS ALSO SHOW
LIGHT MIXED PRECIPITATION FALLING ACROSS THE HILL COUNTRY WITH
ONLY TRACE AMOUNTS REPORTED SO FAR. OTHERWISE...RADAR ECHOES
GENERALLY ON THE INCREASE EARLY THIS MORNING...ESPECIALLY ACROSS
THE NORTHERN HILL COUNTRY INCLUDING KERR...GILLESPIE...LLANO AND
BURNET COUNTIES. THE LATEST HRRR AND NAM12 MODELS TEND TO FAVOR
THE ABOVE MENTIONED AREAS FOR PRECIPITATION TODAY AND WE HAVE
PLACED THE HIGHEST CHANCE FOR WINTRY PRECIPITATION HERE. WE/LL
NEED TO MONITOR THESE AREAS CAREFULLY AS ICE ACCUMULATIONS COULD
ADD UP QUICKER IF MULTIPLE ROUNDS OF PRECIPITATION DEVELOP.
OTHERWISE...WE STILL EXPECT WINTRY PRECIPITATION IN THE FORM OF
FREEZING RAIN TO OCCUR ACROSS THE SOUTHERN EDWARDS PLATEAU...HILL
COUNTRY AND PORTIONS OF THE INTERSTATE 35 CORRIDOR MAINLY NORTH OF
SAN MARCOS. WE STILL EXPECT ICE ACCUMULATIONS TO REMAIN AT OR
BELOW 1/10 OF AN INCH...WITH THE MAIN IMPACTS BEING ON BRIDGES AND
ELEVATED ROADWAYS. THE WINTER WEATHER ADVISORY WILL REMAIN IN
EFFECT UNTIL 6 PM TODAY.
OTHERWISE...TEMPERATURES WILL EITHER REMAIN STEADY OF SLOWLY FALL
TODAY DUE TO THE COMBINATION OF COLD AIR ADVECTION...CLOUD COVER
AND LIGHT PRECIPITATION. FOR THE EVENING AND OVERNIGHT HOURS...WE
EXPECT A FAIRLY QUICK DECREASE IN PRECIPITATION CHANCES FROM WEST
TO EAST ACROSS THE REGION. WE CONTEMPLATED EXPANDING THE WINTER
WEATHER ADVISORY FARTHER EAST TO COVER AREAS MAINLY NORTH OF
I-10/EAST OF I-35. HOWEVER...THE MODELS HAVE BEEN CONSISTENT IN
SHOWING A RATHER QUICK DECREASE IN THE PRECIPITATION THIS EVENING.
WE/LL CONTINUE TO HIGHLIGHT THIS REGION IN A SPECIAL WEATHER
STATEMENT TO COVER THE COLD TEMPERATURES AND POTENTIAL FOR LIGHT
WINTRY PRECIPITATION. PRECIPITATION CHANCES TEMPORARILY DECREASE
ON TUESDAY AS MID-LEVEL DRYING/WEAK SUBSIDENCE MOVE IN FROM THE
WEST.
LONG TERM (TUESDAY NIGHT THROUGH SUNDAY)...
ANOTHER UPPER LEVEL TROUGH APPROACHES SOUTH CENTRAL TEXAS FROM THE
WEST TUESDAY NIGHT. THE LATEST ROUND OF MODEL GUIDANCE IS SHOWING
THIS SYSTEM TO BE A LITTLE STRONGER WHEN COMPARED TO PREVIOUS
RUNS. WE HAVE INCREASED PRECIPITATION CHANCES SLIGHTLY FOR TUESDAY
NIGHT AND WEDNESDAY. AT THIS TIME...TEMPERATURES ARE EXPECTED TO
REMAIN ABOVE FREEZING TUESDAY NIGHT...SO WE/LL KEEP THE
PRECIPITATION AS ALL LIQUID. AS THE ABOVE MENTIONED UPPER LEVEL
STORM SYSTEM DEPARTS THE REGION BY LATE WEDNESDAY... ANOTHER
SYSTEM MOVES THROUGH ON THURSDAY. WE/LL KEEP THE FORECAST DRY AS
MOISTURE WILL BE LACKING. WE DO EXPECT ANOTHER SHOT OF COOLER AIR
TO MOVE THROUGH ON THURSDAY...FOLLOWED BY COOLER TEMPERATURES ON
FRIDAY. WE/LL KEEP A SLIGHT CHANCE FOR LIGHT RAIN IN THE FORECAST
FRIDAY THROUGH SUNDAY AS SOUTHERLY FLOW JUST ABOVE THE COLD
SURFACE AIR BEGINS TO SET UP A WARM AIR ADVECTION PATTERN.
&&
.PRELIMINARY POINT TEMPS/POPS...
AUSTIN CAMP MABRY 34 30 43 36 58 / 70 30 20 30 30
AUSTIN BERGSTROM INTL AIRPORT 35 30 43 34 57 / 70 30 20 30 30
NEW BRAUNFELS MUNI AIRPORT 36 32 45 37 61 / 60 30 10 30 20
BURNET MUNI AIRPORT 31 26 41 34 57 / 80 30 20 30 20
DEL RIO INTL AIRPORT 38 36 52 41 68 / 50 10 10 10 -
GEORGETOWN MUNI AIRPORT 33 27 42 34 56 / 70 40 20 30 30
HONDO MUNI AIRPORT 37 33 48 38 65 / 50 20 10 20 -
SAN MARCOS MUNI AIRPORT 36 31 44 37 59 / 70 30 10 30 20
LA GRANGE - FAYETTE REGIONAL 38 33 43 38 57 / 70 40 20 30 30
SAN ANTONIO INTL AIRPORT 38 32 45 38 62 / 60 30 10 20 10
STINSON MUNI AIRPORT 39 33 46 39 63 / 60 30 10 20 10
&&
.EWX WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY UNTIL 6 PM CST THIS EVENING FOR THE
FOLLOWING COUNTIES: BANDERA...BLANCO...BURNET...EDWARDS...
GILLESPIE...HAYS...KENDALL...KERR...LLANO...REAL...TRAVIS...VAL
VERDE...WILLIAMSON.
&&
$$
MESOSCALE/AVIATION...03
SYNOPTIC/GRIDS...24
AREA FORECAST DISCUSSION
NWS AUSTIN/SAN ANTONIO TX
457 AM CST MON FEB 23 2015
.SHORT TERM (TODAY THROUGH TUESDAY)...
EARLY MORNING OBSERVATIONS SHOW THE FREEZING LINE ROUGHLY ALONG A
GEORGETOWN TO BOERNE TO COMSTOCK LINE. OBSERVATIONS ALSO SHOW
LIGHT MIXED PRECIPITATION FALLING ACROSS THE HILL COUNTRY WITH
ONLY TRACE AMOUNTS REPORTED SO FAR. OTHERWISE...RADAR ECHOES
GENERALLY ON THE INCREASE EARLY THIS MORNING...ESPECIALLY ACROSS
THE NORTHERN HILL COUNTRY INCLUDING KERR...GILLESPIE...LLANO AND
BURNET COUNTIES. THE LATEST HRRR AND NAM12 MODELS TEND TO FAVOR
THE ABOVE MENTIONED AREAS FOR PRECIPITATION TODAY AND WE HAVE
PLACED THE HIGHEST CHANCE FOR WINTRY PRECIPITATION HERE. WE/LL
NEED TO MONITOR THESE AREAS CAREFULLY AS ICE ACCUMULATIONS COULD
ADD UP QUICKER IF MULTIPLE ROUNDS OF PRECIPITATION DEVELOP.
OTHERWISE...WE STILL EXPECT WINTRY PRECIPITATION IN THE FORM OF
FREEZING RAIN TO OCCUR ACROSS THE SOUTHERN EDWARDS PLATEAU...HILL
COUNTRY AND PORTIONS OF THE INTERSTATE 35 CORRIDOR MAINLY NORTH OF
SAN MARCOS. WE STILL EXPECT ICE ACCUMULATIONS TO REMAIN AT OR
BELOW 1/10 OF AN INCH...WITH THE MAIN IMPACTS BEING ON BRIDGES AND
ELEVATED ROADWAYS. THE WINTER WEATHER ADVISORY WILL REMAIN IN
EFFECT UNTIL 6 PM TODAY.
OTHERWISE...TEMPERATURES WILL EITHER REMAIN STEADY OF SLOWLY FALL
TODAY DUE TO THE COMBINATION OF COLD AIR ADVECTION...CLOUD COVER
AND LIGHT PRECIPITATION. FOR THE EVENING AND OVERNIGHT HOURS...WE
EXPECT A FAIRLY QUICK DECREASE IN PRECIPITATION CHANCES FROM WEST
TO EAST ACROSS THE REGION. WE CONTEMPLATED EXPANDING THE WINTER
WEATHER ADVISORY FARTHER EAST TO COVER AREAS MAINLY NORTH OF
I-10/EAST OF I-35. HOWEVER...THE MODELS HAVE BEEN CONSISTENT IN
SHOWING A RATHER QUICK DECREASE IN THE PRECIPITATION THIS EVENING.
WE/LL CONTINUE TO HIGHLIGHT THIS REGION IN A SPECIAL WEATHER
STATEMENT TO COVER THE COLD TEMPERATURES AND POTENTIAL FOR LIGHT
WINTRY PRECIPITATION. PRECIPITATION CHANCES TEMPORARILY DECREASE
ON TUESDAY AS MID-LEVEL DRYING/WEAK SUBSIDENCE MOVE IN FROM THE
WEST.
&&
.LONG TERM (TUESDAY NIGHT THROUGH SUNDAY)...
ANOTHER UPPER LEVEL TROUGH APPROACHES SOUTH CENTRAL TEXAS FROM THE
WEST TUESDAY NIGHT. THE LATEST ROUND OF MODEL GUIDANCE IS SHOWING
THIS SYSTEM TO BE A LITTLE STRONGER WHEN COMPARED TO PREVIOUS
RUNS. WE HAVE INCREASED PRECIPITATION CHANCES SLIGHTLY FOR TUESDAY
NIGHT AND WEDNESDAY. AT THIS TIME...TEMPERATURES ARE EXPECTED TO
REMAIN ABOVE FREEZING TUESDAY NIGHT...SO WE/LL KEEP THE
PRECIPITATION AS ALL LIQUID. AS THE ABOVE MENTIONED UPPER LEVEL
STORM SYSTEM DEPARTS THE REGION BY LATE WEDNESDAY... ANOTHER
SYSTEM MOVES THROUGH ON THURSDAY. WE/LL KEEP THE FORECAST DRY AS
MOISTURE WILL BE LACKING. WE DO EXPECT ANOTHER SHOT OF COOLER AIR
TO MOVE THROUGH ON THURSDAY...FOLLOWED BY COOLER TEMPERATURES ON
FRIDAY. WE/LL KEEP A SLIGHT CHANCE FOR LIGHT RAIN IN THE FORECAST
FRIDAY THROUGH SUNDAY AS SOUTHERLY FLOW JUST ABOVE THE COLD
SURFACE AIR BEGINS TO SET UP A WARM AIR ADVECTION PATTERN.
&&
.PRELIMINARY POINT TEMPS/POPS...
AUSTIN CAMP MABRY 34 30 43 36 58 / 70 30 20 30 30
AUSTIN BERGSTROM INTL AIRPORT 35 30 43 34 57 / 70 30 20 30 30
NEW BRAUNFELS MUNI AIRPORT 36 32 45 37 61 / 60 30 10 30 20
BURNET MUNI AIRPORT 31 26 41 34 57 / 80 30 20 30 20
DEL RIO INTL AIRPORT 38 36 52 41 68 / 50 10 10 10 -
GEORGETOWN MUNI AIRPORT 33 27 42 34 56 / 70 40 20 30 30
HONDO MUNI AIRPORT 37 33 48 38 65 / 50 20 10 20 -
SAN MARCOS MUNI AIRPORT 36 31 44 37 59 / 70 30 10 30 20
LA GRANGE - FAYETTE REGIONAL 38 33 43 38 57 / 70 40 20 30 30
SAN ANTONIO INTL AIRPORT 38 32 45 38 62 / 60 30 10 20 10
STINSON MUNI AIRPORT 39 33 46 39 63 / 60 30 10 20 10
&&
.EWX WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY UNTIL 6 PM CST THIS EVENING FOR THE
FOLLOWING COUNTIES: BANDERA...BLANCO...BURNET...EDWARDS...
GILLESPIE...HAYS...KENDALL...KERR...LLANO...REAL...TRAVIS...VAL
VERDE...WILLIAMSON.
&&
$$
MESOSCALE/AVIATION...03
SYNOPTIC/GRIDS...24
AREA FORECAST DISCUSSION
NWS SAN FRANCISCO BAY AREA
946 AM PST MON FEB 23 2015
.SYNOPSIS...AN UPPER LEVEL SYSTEM OVER THE REGION WILL RESULT IN A
SLIGHT CHANCE OF SHOWERS AND EMBEDDED THUNDERSTORMS OVER PORTIONS
OF MONTEREY AND SAN BENITO COUNTIES THIS AFTERNOON. DRY AND MILD
WEATHER WILL RETURN TUESDAY AND PERSIST THROUGH MIDWEEK, THEN A
POSSIBLE PATTERN CHANGE WILL POTENTIALLY BRING PRECIPITATION BACK
TO THE REGION BY THE END OF THE WEEK.
&&
.DISCUSSION...AS OF 8:50 AM PST MONDAY...UPPER LEVEL LOW CONTINUES
TO ROTATE OFF TO OUR SOUTHEAST WITH LIMITED INSTABILITY AND MOISTURE
FORECAST TO BE ACROSS SAN BENITO AND INTERIOR MONTEREY COUNTY
THROUGH THE DAY. LATEST RUN OF THE HRRR SHOWS A FEW SHOWERS
POPPING UP AROUND NOON AND CONTINUING TO ABOUT SUNSET. WILL ALSO
KEEP A MENTION OF THUNDERSTORMS GOING AS WELL. WINDS ARE STILL
LOCALLY GUSTY OVER THE NORTH AND EAST HILLS ALTHOUGH SPEEDS SHOULD
CONTINUE TO DIMINISH THROUGH THE DAY.
OUTSIDE OF THOSE ISSUES...QUIET WEATHER ACROSS OUR CWA WITH HIGHS
GENERALLY IN THE 60S. CURRENT FORECAST APPEARS ON TRACK SO NO
MAJOR UPDATES PLANNED AT THIS TIME.
.PREVIOUS DISCUSSION...GENERALLY CLEAR SKIES ACROSS THE REGION
THIS MORNING AS A COOL...DRY AIR MASS REMAINS ALOFT. NORTHERLY
WINDS CONTINUE TO BE BREEZY WITH GUSTS OF 40 TO 50 MPH IN THE MOST
EXPOSED LOCATIONS IN THE HIGHER ELEVATIONS ACROSS THE NORTH BAY
AND EAST BAY. THIS HAS RESULTED IN A GOOD AMOUNT OF MIXING AND
TEMPERATURES GENERALLY REMAIN IN THE 50S IN MOST VALLEY LOCATIONS
ACROSS THE NORTH. EXPECTING THESE WIND SPEEDS TO PERSIST THROUGH
THE MORNING HOURS AND WILL KEEP THE WIND ADVISORY IN EFFECT UNTIL
10 AM PST. AS THE PRESSURE GRADIENT RELAXES...WIND SPEEDS WILL
DIMINISH SOME BY THIS AFTERNOON.
THE MID/UPPER LEVEL SYSTEM THAT BROUGHT SCATTERED SHOWERS AND A
FEW THUNDERSTORMS TO THE REGION YESTERDAY CONTINUES TO BE
POSITIONED OVER CENTRAL CALIFORNIA AND NEVADA AT THIS HOUR.
LINGERING MOISTURE COMBINED WITH MID/UPPER LEVEL SUPPORT WILL
RESULT IN ISOLATED SHOWERS AND THUNDERSTORMS AGAIN OVER MONTEREY
AND SAN BENITO COUNTIES THIS AFTERNOON. HOWEVER...SHOWER ACTIVITY
IS EXPECTED TO BE LESS WIDESPREAD TODAY WITH DRIER AIR WRAPPING
AROUND THE WESTERN PERIPHERY OF THE UPPER LOW. RAIN CHANCES WILL
COME TO AN END BY LATE THIS EVENING AS THE UPPER LEVEL FEATURE
EJECTS TOWARD THE DESERT SOUTHWEST ON TUESDAY. MEANWHILE...THE
UPPER LEVEL RIDGE OFF OF THE WEST COAST WILL RESULT IN DRY
WEATHER CONDITIONS AND A SLIGHT WARMING TREND THROUGH AT LEAST
THURSDAY NIGHT.
THE FORECAST MODELS CONTINUE TO DEPICT A MID/UPPER LEVEL TROUGH
DROPPING OUT OF THE GULF OF ALASKA LATE THIS WEEK THAT WILL THEN
SLIDE DOWN THE WEST COAST THIS WEEKEND. AS A RESULT...WILL
MAINTAIN PRECIPITATION CHANCES OVER THE NORTH BAY ON FRIDAY AND
ACROSS MUCH OF THE REGION INTO SATURDAY NIGHT. WHILE CONFIDENCE
HAS INCREASED SLIGHTLY FOR SOME SORT OF A PATTERN CHANGE...THERE
REMAINS INCONSISTENCY AMONG THE MEDIUM RANGE MODELS LATE IN THE
FORECAST PERIOD.
&&
.AVIATION...AS OF 9:45 AM PST MONDAY...DRY NORTHERLY FLOW WILL
CONTINUE ACROSS THE REGION THROUGH TUESDAY...RESULTING IN VFR
CONDITIONS AT ALL TERMINALS. LOCAL GUSTY NORTH TO NORTHEAST WINDS
ON MONDAY MORNING WILL GRADUALLY TAPER OFF MONDAY AFTERNOON AND
EVENING.
VICINITY OF KSFO...VFR. LIGHT TO MODERATE NORTH TO NORTHEAST WINDS
THROUGH MID AFTERNOON TURNING TO LIGHT NORTHWEST BY LATE AFTERNOON.
KSFO BRIDGE APPROACH...SIMILAR TO SFO.
MONTEREY BAY AREA TERMINALS...VFR. LIGHT WINDS.
&&
.MARINE...AS OF 3:59 AM PST MONDAY...HIGH PRESSURE WILL CONTINUE
OVER THE GREAT BASIN AND NORTHERNMOST CALIFORNIA TODAY AND
TONIGHT. THIS WILL RESULT IN A LIGHT TO MODERATE NORTHERLY WIND.
WINDS WILL BECOME NORTHWESTERLY OVER THE COASTAL WATERS BY ON
TUESDAY. A LOW PRESSURE AREA OVER THE GULF OF ALASKA WILL MOVE TO
THE BAY AREA FRIDAY BRINGING WITH IT A CHANCE OF SHOWERS.
&&
.MTR WATCHES/WARNINGS/ADVISORIES...
.TDAY...SCA...SF BAY NORTH OF THE BAY BRIDGE UNTIL 3 PM
&&
$$
PUBLIC FORECAST: BELL/RGASS
AVIATION: DYKEMA
MARINE: CANEPA
VISIT US AT WEATHER.GOV/SANFRANCISCO
FOLLOW US ON FACEBOOK, TWITTER, AND YOUTUBE AT:
WWW.FACEBOOK.COM/NWSBAYAREA
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AREA FORECAST DISCUSSION
NWS SAN FRANCISCO BAY AREA
903 AM PST MON FEB 23 2015
.SYNOPSIS...AN UPPER LEVEL SYSTEM OVER THE REGION WILL RESULT IN A
SLIGHT CHANCE OF SHOWERS AND EMBEDDED THUNDERSTORMS OVER PORTIONS
OF MONTEREY AND SAN BENITO COUNTIES THIS AFTERNOON. DRY AND MILD
WEATHER WILL RETURN TUESDAY AND PERSIST THROUGH MIDWEEK, THEN A
POSSIBLE PATTERN CHANGE WILL POTENTIALLY BRING PRECIPITATION BACK
TO THE REGION BY THE END OF THE WEEK.
&&
.DISCUSSION...AS OF 8:50 AM PST MONDAY...UPPER LEVEL LOW CONTINUES
TO ROTATE OFF TO OUR SOUTHEAST WITH LIMITED INSTABILITY AND MOISTURE
FORECAST TO BE ACROSS SAN BENITO AND INTERIOR MONTEREY COUNTY
THROUGH THE DAY. LATEST RUN OF THE HRRR SHOWS A FEW SHOWERS
POPPING UP AROUND NOON AND CONTINUING TO ABOUT SUNSET. WILL ALSO
KEEP A MENTION OF THUNDERSTORMS GOING AS WELL. WINDS ARE STILL
LOCALLY GUSTY OVER THE NORTH AND EAST HILLS ALTHOUGH SPEEDS SHOULD
CONTINUE TO DIMINISH THROUGH THE DAY.
OUTSIDE OF THOSE ISSUES...QUIET WEATHER ACROSS OUR CWA WITH HIGHS
GENERALLY IN THE 60S. CURRENT FORECAST APPEARS ON TRACK SO NO
MAJOR UPDATES PLANNED AT THIS TIME.
.PREVIOUS DISCUSSION...GENERALLY CLEAR SKIES ACROSS THE REGION
THIS MORNING AS A COOL...DRY AIR MASS REMAINS ALOFT. NORTHERLY
WINDS CONTINUE TO BE BREEZY WITH GUSTS OF 40 TO 50 MPH IN THE MOST
EXPOSED LOCATIONS IN THE HIGHER ELEVATIONS ACROSS THE NORTH BAY
AND EAST BAY. THIS HAS RESULTED IN A GOOD AMOUNT OF MIXING AND
TEMPERATURES GENERALLY REMAIN IN THE 50S IN MOST VALLEY LOCATIONS
ACROSS THE NORTH. EXPECTING THESE WIND SPEEDS TO PERSIST THROUGH
THE MORNING HOURS AND WILL KEEP THE WIND ADVISORY IN EFFECT UNTIL
10 AM PST. AS THE PRESSURE GRADIENT RELAXES...WIND SPEEDS WILL
DIMINISH SOME BY THIS AFTERNOON.
THE MID/UPPER LEVEL SYSTEM THAT BROUGHT SCATTERED SHOWERS AND A
FEW THUNDERSTORMS TO THE REGION YESTERDAY CONTINUES TO BE
POSITIONED OVER CENTRAL CALIFORNIA AND NEVADA AT THIS HOUR.
LINGERING MOISTURE COMBINED WITH MID/UPPER LEVEL SUPPORT WILL
RESULT IN ISOLATED SHOWERS AND THUNDERSTORMS AGAIN OVER MONTEREY
AND SAN BENITO COUNTIES THIS AFTERNOON. HOWEVER...SHOWER ACTIVITY
IS EXPECTED TO BE LESS WIDESPREAD TODAY WITH DRIER AIR WRAPPING
AROUND THE WESTERN PERIPHERY OF THE UPPER LOW. RAIN CHANCES WILL
COME TO AN END BY LATE THIS EVENING AS THE UPPER LEVEL FEATURE
EJECTS TOWARD THE DESERT SOUTHWEST ON TUESDAY. MEANWHILE...THE
UPPER LEVEL RIDGE OFF OF THE WEST COAST WILL RESULT IN DRY
WEATHER CONDITIONS AND A SLIGHT WARMING TREND THROUGH AT LEAST
THURSDAY NIGHT.
THE FORECAST MODELS CONTINUE TO DEPICT A MID/UPPER LEVEL TROUGH
DROPPING OUT OF THE GULF OF ALASKA LATE THIS WEEK THAT WILL THEN
SLIDE DOWN THE WEST COAST THIS WEEKEND. AS A RESULT...WILL
MAINTAIN PRECIPITATION CHANCES OVER THE NORTH BAY ON FRIDAY AND
ACROSS MUCH OF THE REGION INTO SATURDAY NIGHT. WHILE CONFIDENCE
HAS INCREASED SLIGHTLY FOR SOME SORT OF A PATTERN CHANGE...THERE
REMAINS INCONSISTENCY AMONG THE MEDIUM RANGE MODELS LATE IN THE
FORECAST PERIOD.
&&
.AVIATION...AS OF 4:12 AM PST MONDAY...IT`S MUCH DRIER AROUND THE
AREA. DEWPOINT TEMPS AND HUMIDITY HAVE TUMBLED DOWNWARD AS
DOWNSLOPING WINDS OFF THE SIERRA NEVADA AND COASTAL MTNS CONTINUE
TO SUPPORT DRY WEATHER /VFR CONDITIONS/ FOR THE PERIOD. AREAS OF
GUSTY N-NE WINDS ARE PERSISTING THIS MORNING WITH THE HIGHER GUSTS
IN THE EAST AND NORTH BAY MTNS AND HILLS. SURFACE WINDS AT THE KOAK
TERMINAL HAVE BEEN LOWERING ENOUGH TO CONSIDER INCLUDING NON-CONVECTIVE
LOW LEVEL WIND SHEAR IN THE TAF BUT WILL WAIT ON THIS AS THE SURFACE
WINDS HAVE RECENTLY PICKED BACK UP AGAIN. THE NORTHERLY GRADIENT
UKI-STS IS STRONG AT 2.5 MB. THE WMC-SFO AND ACV-SFO GRADIENTS ARE
9.1 MB AND 5.3 MB RESPECTIVELY AND THE NAM MODEL FORECASTS THEM TO
STRENGTHEN MORE TODAY THEN TAPER OFF SLOWLY BEGINNING VERY LATE
TONIGHT AND TUESDAY. EPAC UPPER LEVEL RIDGING WILL SLOWLY EDGE
EASTWARD BACK OVER CA THROUGH MID-WEEK.
VICINITY OF KSFO...VFR.
KSFO BRIDGE APPROACH...SIMILAR TO SFO.
MONTEREY BAY AREA TERMINALS...VFR.
&&
.MARINE...AS OF 3:59 AM PST MONDAY...HIGH PRESSURE WILL CONTINUE
OVER THE GREAT BASIN AND NORTHERNMOST CALIFORNIA TODAY AND
TONIGHT. THIS WILL RESULT IN A LIGHT TO MODERATE NORTHERLY WIND.
WINDS WILL BECOME NORTHWESTERLY OVER THE COASTAL WATERS BY ON
TUESDAY. A LOW PRESSURE AREA OVER THE GULF OF ALASKA WILL MOVE TO
THE BAY AREA FRIDAY BRINGING WITH IT A CHANCE OF SHOWERS.
&&
.MTR WATCHES/WARNINGS/ADVISORIES...
.TDAY...WIND ADVISORY...NORTH AND EAST BAY HILLS UNTIL 10 AM
SCA...SF BAY NORTH OF THE BAY BRIDGE UNTIL 3 PM
&&
$$
PUBLIC FORECAST: BELL/RGASS
AVIATION/MARINE: CANEPA
VISIT US AT WEATHER.GOV/SANFRANCISCO
FOLLOW US ON FACEBOOK, TWITTER, AND YOUTUBE AT:
WWW.FACEBOOK.COM/NWSBAYAREA
WWW.TWITTER.COM/NWSBAYAREA
WWW.YOUTUBE.COM/NWSBAYAREA
AREA FORECAST DISCUSSION
NWS PUEBLO CO
315 PM MST MON FEB 23 2015
.SHORT TERM...(THIS EVENING THROUGH TUESDAY)
ISSUED AT 314 PM MST MON FEB 23 2015
AN UPR LOW OVR CA TODAY IS EXPECTED TO MOVE EASTWARD TONIGHT...
MOVING INTO NORTH CENTRAL AZ BY 12Z TUE...AND THEN WEAKENING AND
MOVING SOUTHEASTWARD THRU NM ON TUE.
SNOW HAS CONTINUED FALLING OVER THE MTNS AND HIGH VALLEYS THIS
AFTERNOON. IN THE SAN LUIS VALLEY THE SNOW HAS NOT BEEN WIDESPREAD
AND IT FAIRLY SPOTTY AND WL CANCEL SNOW ADVISORY AT 3 PM.
OVER THE SANGRE DE CRISTO MTNS THE SNOW IS ALSO BECOMING MORE
SPOTTY...EXCEPT OVR THE FAR SRN AREAS NR THE NEW MEXICO BORDER. WL
ALLOW THAT ADVISORY TO EXPIRE AT 3 PM.
THE NAM AND HRRR SHOW PCPN CHANCE DECREASING RAPIDLY IN THE EVENING
HOURS OVR MOST OF THE MTNS AND HIGH VALLEY AREAS. THE NAM KEEPS
WIDESPREAD SNOW OVR THE ERN SAN JUANS EARLY IN THE EVENING. WEB CAMS
SHOULD LITTLE IN THE WAY OF SNOWFALL CURRENTLY AT LXV AND MONARCH
PASS...SO WL CANCEL THE WARNINGS FOR LAKE AND CHAFFEE COUNTIES AT 3
PM...ALONG WITH CANCELING WARNINGS FOR ZONES 64 AND 65...BUT WL
LEAVE WARNINGS IN EFFECT UNTIL 5 PM FOR ZONES 66 AND 67. WL LEAVE
THE WARNING FOR THE ERN SAN JUANS (ZONE 68) IN EFFECT UNTIL 06Z.
ERN SAN JUANS COULD GET ANOTHER FEW INCHES IN THE EVENING
HOURS...WITH LITTLE ADDITIONAL ACCUMULATION AFTER MIDNIGHT AS THE
SNOW TAPERS OFF.
BY 09Z THE NAM SHOWS DRY WX OVR THE ENTIRE FORECAST AREA...WITH DRY
CONDITIONS THRU AT LEAST MIDMORNING TUE. THE NAM THEN SHOWS THE
POTENTIAL FOR SOME LIGHT PCPN AGAIN OVR THE SW MTNS AS THE UPR LOW
MOVES INTO NM. HOWEVER THE GFS HAS LIGHT PCPN CONTINUING OVR THE SW
MTNS AND THE SANGRES THRU THE NIGHT AND THRU TUE. THE ECMWF IS
SIMILAR TO THE GFS BUT DOES NOT SPREAD THE PCPN ON TUE QUITE AS FAR
NORTH. HAVE DECIDED TO KEEP LOW POPS OVR THE SANGRES AND PORTIONS
OF THE CENTRAL MTNS THRU TONIGHT AND TUE...WITH HIGHER POPS OVR THE
SW MTNS DURING THIS SAME TIME-FRAME...BUT NOT EXPECTING ANYTHING
MORE THAN SOME LIGHT ACCUMULATIONS.
IT IS POSSIBLE FOR THE SAN LUIS VALLEY TO SEE SOME VERY LIGHT SNOW
DEVELOP AGAIN AS LOW CLOUDS COVER MUCH OF THE AREA.
TEMPS WL BE WARMER ON TUE...BUT THE SNOW COVER IN MANY LOCATIONS WL
LIMIT THE AMOUNT OF WARMING AND SO WL STAY BELOW GUIDANCE IN MANY
AREAS.
.LONG TERM...(TUESDAY NIGHT THROUGH MONDAY)
ISSUED AT 314 PM MST MON FEB 23 2015
...ACTIVE AND COLD WEATHER PATTERN TO CONTINUE...
MODELS IN GOOD AGREEMENT WITH ACTIVE WEATHER PERSISTING THROUGH
THE EXTENDED PERIOD. SEVERAL DISTURBANCES WILL KEEP PERIODS OF
MODERATE TO HEAVY SNOW GOING FOR MOST OF SOUTHERN COLORADO.
TUESDAY NIGHT...AN UPPER LEVEL DISTURBANCE WILL BE EXITING THE
DESERT SOUTHWEST INTO TEXAS EARLY TUESDAY NIGHT. LIGHT LINGERING
SNOWFALL OVER THE SOUTHERN SAN JUANS SHOULD COME TO AN END BY
MIDNIGHT. A SECONDARY DISTURBANCE WILL BE DROPPING SOUTH OUT OF
THE NORTHERN ROCKIES LATE TUESDAY NIGHT WITH LIGHT SNOW DEVELOPING
OVER THE CENTRAL MOUNTAINS BY WEDNESDAY MORNING.
WEDNESDAY AND THURSDAY...THE SHORTWAVE OVER THE NORTHERN ROCKIES
IS FORECAST TO STRENGTHEN AND DROP SOUTH ACROSS COLORADO THROUGH
THIS PERIOD. THERE ARE A FEW SLIGHT MODEL DIFFERENCES WHICH COULD
PLAY A ROLE IN HOW MUCH SNOW SOME AREAS SEE. SNOW WILL BE ON THE
INCREASE OVER THE CENTRAL MOUNTAINS WEDNESDAY MORNING AND SPREAD
SOUTH AND EAST INTO THE PALMER DIVIDE BY WEDNESDAY AFTERNOON.
ACROSS THE PLAINS...A STRONG COLD FRONT IS FORECAST TO DROP SOUTH
BY LATE WEDNESDAY AFTERNOON. FLOW BEHIND THE COLD FRONT IS
FORECAST TO TRANSITION NORTHEASTERLY HELPING TO PRODUCE LOW LEVEL
UPSLOPE FLOW AS THE UPPER DISTURBANCE DROPS ACROSS THE AREA.
HEAVY SNOW IS LIKELY TO DEVELOP OVER THE EASTERN MOUNTAINS...DOWN
INTO THE I-25 CORRIDOR WEDNESDAY EVENING AND CONTINUE INTO
THURSDAY MORNING. SNOW TOTALS LOOK TO BE HIGHEST OVER THE CENTRAL
MOUNTAINS WHERE ANOTHER FOOT OR MORE OF SNOW IS EXPECTED...WHILE
THE LOWER ELEVATIONS ALONG THE I-25 CORRIDOR WILL SEE 2 TO 6
INCHES. LIGHT SNOW IS EXPECTED ACROSS ALL THE EASTERN PLAINS WITH
1 TO 3 INCHES POSSIBLE. THE MAIN MODEL DIFFERENCE IS WITH THE NAM
WHICH KEEPS LOW AND MID LEVEL FLOW A BIT MORE NORTHERLY...WHICH
WOULD LIMIT UPSLOPE EFFECTS AND SNOW TOTALS ALONG THE I-25
CORRIDOR. THIS WILL NEED TO BE MONITORED. THE HEAVIEST SNOW WILL
COME TO AN END BY LATE THURSDAY MORNING...WITH LIGHT SNOW LIKELY
LINGERING ACROSS THE AREA THROUGH THURSDAY NIGHT. TEMPERATURES
WILL BE COLD WITH 30S FOR HIGHS ON WEDNESDAY...WITH 20S ON
THURSDAY.
FRIDAY...BROAD NORTHWEST FLOW WILL TRANSITION TO SOUTHWESTERLY
FLOW AS THE NEXT UPPER LEVEL DISTURBANCE DROPS SOUTH ALONG THE
WEST COAST. WEAK ENERGY MOVING ACROSS THE REGION WILL LIKELY KEEP
LIGHT SNOW GOING OVER THE MOUNTAINS. TEMPERATURES WILL REMAIN COLD
ACROSS THE PLAINS WITH 20S FOR HIGHS.
SATURDAY THROUGH MONDAY...THE UPPER SYSTEM ALONG THE WEST COAST IS
FORECAST TO STRENGTHEN AND SLOWLY DRIFT SOUTH INTO SOUTHERN
CALIFORNIA BY EARLY NEXT WEEK. SOUTHWESTERLY FLOW WILL TAP INTO
SUBTROPICAL MOISTURE AND SPREAD IT NORTHEASTWARD ACROSS COLORADO.
THIS WILL SET THE STAGE FOR HEAVY SNOWFALL ALONG THE CONTINENTAL
DIVIDE THROUGH THE WEEKEND...WITH THE HEAVIEST SNOWFALL OVER THE
SAN JUAN RANGE. MODELS KEEP LIGHT SNOW ACROSS ALL OF SOUTHERN
COLORADO THROUGH THE WEEKEND. COLD AIR WILL REMAIN IN PLACE WITH
30S FOR HIGHS ACROSS THE LOWER ELEVATIONS. MOZLEY
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z TUESDAY EVENING)
ISSUED AT 314 PM MST MON FEB 23 2015
KPUB IS EXPECTED TO HAVE VFR CONDITIONS TONIGHT AND TUESDAY. KALS
SHOULD SEE VFR CONDITIONS IN THE EVENING HOURS UNLESS SOME SHOWERS
ARE IN THE VCNTY WHICH COULD LEAD TO BRIEF MVFR CONDITIONS. THEN
LATE TONIGHT KALS SHOULD SEE LOW CLOUDS AND FOG DEVELOP WITH IFR OR
LIFR CONDITIONS INTO MIDMORNING TUE...AND THEN VFR CONDITIONS FOR
THE LATE MORNING AND AFTERNOON. KCOS MAY STILL HAVE SOME VERY LIGHT
SNOW IN THE VCNTY IN THE EARLY EVENING HOURS WITH MVFR OR IFR
CONDITIONS...THEN BY LATE EVENING CONDITIONS ARE EXPECTED TO BECOME
VFR AS SFC WINDS BECOME NW TO N.
&&
.PUB WATCHES/WARNINGS/ADVISORIES...
WINTER STORM WARNING UNTIL 11 PM MST THIS EVENING FOR COZ068.
WINTER STORM WARNING UNTIL 5 PM MST THIS AFTERNOON FOR COZ066-
067.
&&
$$
SHORT TERM...28
LONG TERM...MOZLEY
AVIATION...28
AREA FORECAST DISCUSSION
NWS PUEBLO CO
304 PM MST MON FEB 23 2015
.SHORT TERM...(THIS EVENING THROUGH TUESDAY)
ISSUED AT 303 PM MST MON FEB 23 2015
AN UPR LOW OVR CA TODAY IS EXPECTED TO MOVE EASTWARD TONIGHT...
MOVING INTO NORTH CENTRAL AZ BY 12Z TUE...AND THEN WEAKENING AND
MOVING SOUTHEASTWARD THRU NM ON TUE.
SNOW HAS CONTINUED FALLING OVER THE MTNS AND HIGH VALLEYS THIS
AFTERNOON. IN THE SAN LUIS VALLEY THE SNOW HAS NOT BEEN WIDESPREAD
AND IT FAIRLY SPOTTY AND WL CANCEL SNOW ADVISORY AT 3 PM.
OVER THE SANGRE DE CRISTO MTNS THE SNOW IS ALSO BECOMING MORE
SPOTTY...EXCEPT OVR THE FAR SRN AREAS NR THE NEW MEXICO BORDER. WL
ALLOW THAT ADVISORY TO EXPIRE AT 3 PM.
THE NAM AND HRRR SHOW PCPN CHANCE DECREASING RAPIDLY IN THE EVENING
HOURS OVR MOST OF THE MTNS AND HIGH VALLEY AREAS. THE NAM KEEPS
WIDESPREAD SNOW OVR THE ERN SAN JUANS EARLY IN THE EVENING. WEB CAMS
SHOULD LITTLE IN THE WAY OF SNOWFALL CURRENTLY AT LXV AND MONARCH
PASS...SO WL CANCEL THE WARNINGS FOR LAKE AND CHAFFEE COUNTIES AT 3
PM...ALONG WITH CANCELING WARNINGS FOR ZONES 64 AND 65...BUT WL
LEAVE WARNINGS IN EFFECT UNTIL 5 PM FOR ZONES 66 AND 67. WL LEAVE
THE WARNING FOR THE ERN SAN JUANS (ZONE 68) IN EFFECT UNTIL 06Z.
ERN SAN JUANS COULD GET ANOTHER FEW INCHES IN THE EVENING
HOURS...WITH LITTLE ADDITIONAL ACCUMULATION AFTER MIDNIGHT AS THE
SNOW TAPERS OFF.
BY 09Z THE NAM SHOWS DRY WX OVR THE ENTIRE FORECAST AREA...WITH DRY
CONDITIONS THRU AT LEAST MIDMORNING TUE. THE NAM THEN SHOWS THE
POTENTIAL FOR SOME LIGHT PCPN AGAIN OVR THE SW MTNS AS THE UPR LOW
MOVES INTO NM. HOWEVER THE GFS HAS LIGHT PCPN CONTINUING OVR THE SW
MTNS AND THE SANGRES THRU THE NIGHT AND THRU TUE. THE ECMWF IS
SIMILAR TO THE GFS BUT DOES NOT SPREAD THE PCPN ON TUE QUITE AS FAR
NORTH. HAVE DECIDED TO KEEP LOW POPS OVR THE SANGRES AND PORTIONS
OF THE CENTRAL MTNS THRU TONIGHT AND TUE...WITH HIGHER POPS OVR THE
SW MTNS DURING THIS SAME TIME-FRAME...BUT NOT EXPECTING ANYTHING
MORE THAN SOME LIGHT ACCUMULATIONS.
IT IS POSSIBLE FOR THE SAN LUIS VALLEY TO SEE SOME VERY LIGHT SNOW
DEVELOP AGAIN AS LOW CLOUDS COVER MUCH OF THE AREA.
TEMPS WL BE WARMER ON TUE...BUT THE SNOW COVER IN MANY LOCATIONS WL
LIMIT THE AMOUNT OF WARMING AND SO WL STAY BELOW GUIDANCE IN MANY
AREAS.
.LONG TERM...(TUESDAY NIGHT THROUGH MONDAY)
ISSUED AT 303 PM MST MON FEB 23 2015
...ACTIVE AND COLD WEATHER PATTERN TO CONTINUE...
MODELS IN GOOD AGREEMENT WITH ACTIVE WEATHER PERSISTING THROUGH
THE EXTENDED PERIOD. SEVERAL DISTURBANCES WILL KEEP PERIODS OF
MODERATE TO HEAVY SNOW GOING FOR MOST OF SOUTHERN COLORADO.
TUESDAY NIGHT...AN UPPER LEVEL DISTURBANCE WILL BE EXITING THE
DESERT SOUTHWEST INTO TEXAS EARLY TUESDAY NIGHT. LIGHT LINGERING
SNOWFALL OVER THE SOUTHERN SAN JUANS SHOULD COME TO AN END BY
MIDNIGHT. A SECONDARY DISTURBANCE WILL BE DROPPING SOUTH OUT OF
THE NORTHERN ROCKIES LATE TUESDAY NIGHT WITH LIGHT SNOW DEVELOPING
OVER THE CENTRAL MOUNTAINS BY WEDNESDAY MORNING.
WEDNESDAY AND THURSDAY...THE SHORTWAVE OVER THE NORTHERN ROCKIES
IS FORECAST TO STRENGTHEN AND DROP SOUTH ACROSS COLORADO THROUGH
THIS PERIOD. THERE ARE A FEW SLIGHT MODEL DIFFERENCES WHICH COULD
PLAY A ROLE IN HOW MUCH SNOW SOME AREAS SEE. SNOW WILL BE ON THE
INCREASE OVER THE CENTRAL MOUNTAINS WEDNESDAY MORNING AND SPREAD
SOUTH AND EAST INTO THE PALMER DIVIDE BY WEDNESDAY AFTERNOON.
ACROSS THE PLAINS...A STRONG COLD FRONT IS FORECAST TO DROP SOUTH
BY LATE WEDNESDAY AFTERNOON. FLOW BEHIND THE COLD FRONT IS
FORECAST TO TRANSITION NORTHEASTERLY HELPING TO PRODUCE LOW LEVEL
UPSLOPE FLOW AS THE UPPER DISTURBANCE DROPS ACROSS THE AREA.
HEAVY SNOW IS LIKELY TO DEVELOP OVER THE EASTERN MOUNTAINS...DOWN
INTO THE I-25 CORRIDOR WEDNESDAY EVENING AND CONTINUE INTO
THURSDAY MORNING. SNOW TOTALS LOOK TO BE HIGHEST OVER THE CENTRAL
MOUNTAINS WHERE ANOTHER FOOT OR MORE OF SNOW IS EXPECTED...WHILE
THE LOWER ELEVATIONS ALONG THE I-25 CORRIDOR WILL SEE 2 TO 6
INCHES. LIGHT SNOW IS EXPECTED ACROSS ALL THE EASTERN PLAINS WITH
1 TO 3 INCHES POSSIBLE. THE MAIN MODEL DIFFERENCE IS WITH THE NAM
WHICH KEEPS LOW AND MID LEVEL FLOW A BIT MORE NORTHERLY...WHICH
WOULD LIMIT UPSLOPE EFFECTS AND SNOW TOTALS ALONG THE I-25
CORRIDOR. THIS WILL NEED TO BE MONITORED. THE HEAVIEST SNOW WILL
COME TO AN END BY LATE THURSDAY MORNING...WITH LIGHT SNOW LIKELY
LINGERING ACROSS THE AREA THROUGH THURSDAY NIGHT. TEMPERATURES
WILL BE COLD WITH 30S FOR HIGHS ON WEDNESDAY...WITH 20S ON
THURSDAY.
FRIDAY...BROAD NORTHWEST FLOW WILL TRANSITION TO SOUTHWESTERLY
FLOW AS THE NEXT UPPER LEVEL DISTURBANCE DROPS SOUTH ALONG THE
WEST COAST. WEAK ENERGY MOVING ACROSS THE REGION WILL LIKELY KEEP
LIGHT SNOW GOING OVER THE MOUNTAINS. TEMPERATURES WILL REMAIN COLD
ACROSS THE PLAINS WITH 20S FOR HIGHS.
SATURDAY THROUGH MONDAY...THE UPPER SYSTEM ALONG THE WEST COAST IS
FORECAST TO STRENGTHEN AND SLOWLY DRIFT SOUTH INTO SOUTHERN
CALIFORNIA BY EARLY NEXT WEEK. SOUTHWESTERLY FLOW WILL TAP INTO
SUBTROPICAL MOISTURE AND SPREAD IT NORTHEASTWARD ACROSS COLORADO.
THIS WILL SET THE STAGE FOR HEAVY SNOWFALL ALONG THE CONTINENTAL
DIVIDE THROUGH THE WEEKEND...WITH THE HEAVIEST SNOWFALL OVER THE
SAN JUAN RANGE. MODELS KEEP LIGHT SNOW ACROSS ALL OF SOUTHERN
COLORADO THROUGH THE WEEKEND. COLD AIR WILL REMAIN IN PLACE WITH
30S FOR HIGHS ACROSS THE LOWER ELEVATIONS. MOZLEY
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z TUESDAY EVENING)
ISSUED AT 303 PM MST MON FEB 23 2015
KPUB IS EXPECTED TO HAVE VFR CONDITIONS TONIGHT AND TUESDAY. KALS
SHOULD SEE VFR CONDITIONS IN THE EVENING HOURS UNLESS SOME SHOWERS
ARE IN THE VCNTY WHICH COULD LEAD TO BRIEF MVFR CONDITIONS. THEN
LATE TONIGHT KALS SHOULD SEE LOW CLOUDS AND FOG DEVELOP WITH IFR OR
LIFR CONDITIONS INTO MIDMORNING TUE...AND THEN VFR CONDITIONS FOR
THE LATE MORNING AND AFTERNOON. KCOS MAY STILL HAVE SOME VERY LIGHT
SNOW IN THE VCNTY IN THE EARLY EVENING HOURS WITH MVFR OR IFR
CONDITIONS...THEN BY LATE EVENING CONDITIONS ARE EXPECTED TO BECOME
VFR AS SFC WINDS BECOME NW TO N.
&&
.PUB WATCHES/WARNINGS/ADVISORIES...
WINTER STORM WARNING UNTIL 11 PM MST THIS EVENING FOR COZ068.
WINTER STORM WARNING UNTIL 5 PM MST THIS AFTERNOON FOR COZ060-
066-067.
&&
$$
SHORT TERM...28
LONG TERM...MOZLEY
AVIATION...28
AREA FORECAST DISCUSSION
NWS GRAND JUNCTION CO
1219 PM MST MON FEB 23 2015
.UPDATE...
ISSUED AT 1134 AM MST MON FEB 23 2015
ALLOWED THE WINTER ADVISORY FOR THE GRAND VALLEY AND THE WINTER
STORM WARNINGS FOR THE DEBEQUE-SILT CORRIDOR AND CENTRAL CO RIVER
VALLEY TO EXPIRE AT NOON. LIGHT SNOW WILL HANG AROUND IN PLACES
ALONG THE I-70 CORRIDOR THIS AFTERNOON BUT AMOUNTS ARE EXPECTED TO
BE AN INCH OR LESS. TEMPS NEAR OR BELOW FREEZING COULD ALSO KEEP
UNTREATED ROADS/SIDEWALKS SLICK. ALSO LET THE WINTER STORM WARNINGS
EXPIRE FOR THE ROAN/TAVAPUTS PLATEAU AND THE FLAT TOPS/WHITE RIVER
PLATEAU AS OVERALL FORCING SLOWLY SHIFTS SOUTHWARD.
SNOW SHOULD REMAIN WIDESPREAD ACROSS SE UT AND SW CO THROUGH THE
AFTERNOON...BUT MODELS INDICATING A LULL IN THE ACTIVITY OR JUST
SOME LIGHT SNOW THIS EVENING. ANOTHER BURST OF A COUPLE INCHES OF
SNOW THEN EXPECTED TOWARD SUNRISE FOR FAR SE UT AND SW CO AS THE
MAIN UPPER LOW CURRENTLY OVER CENTRAL CA MOVES ACROSS NRN AZ.
UPDATE ISSUED AT 1013 AM MST MON FEB 23 2015
SNOW REMAINED WIDESPREAD ACROSS SW CO THIS MORNING...PRETTY MUCH
FROM GRAND JCT AND ASPEN SOUTH. OBSERVATIONS INDICATING THE HEAVIER
SNOW FROM ABOUT MONTROSE/PARADOX VALLEY SOUTH. SNOW ALSO NOTED
ACROSS MUCH OF SE UT. THIS UNDER A BROAD AREA OF UPPER DIVERGENCE/
LOWER (MOISTURE)CONVERGENCE PLUS ISENTROPIC UPGLIDE AND A MOIST
DENDRITIC SNOW GROWTH ZONE. EARLY LOOK AT THIS MORNING`S MODELS SHOW
THE HEAVIER SNOW BAND SLOWLY SHIFTNIG SOUTH WITH SOME REDUCTION IN
UPPER LEVEL SUPPORT AS THE UPPER JET ACROSS NRN AZ AND NRN NM
PROGRESSES EASTWARD. WINTER STORM WARNINGS CONTINUE FOR SE UT AND
SW CO. STILL ASSESSING WHETHER OR NOT TO EXTEND THE HIGHLIGHTS
INTO TUE FOR AT LEAST THE AREAS FROM THE ABAJOS AND SAN JUANS
SOUTH.
LIGHT SNOW IN THE GRAND VALLEY THIS MORNING BELIEVED TO BE MAINLY
DUE TO MOISTURE IN SSW FLOW OVERRUNNING COLD AIR TRAPPED IN THE
VALLEY. NAM12 AND HIGH RESOLUTION RAP MODELS SUGGEST THIS MOIST
OVERRUNNING DECREASES FOR THE GRAND VALLEY THIS AFTERNOON AS FLOW
ALOFT BEGINS TO TAKE ON A MORE NORTHERLY TACK. THESE MODELS ALSO
SHOW ONLY LIGHT SNOW ACCUMS THERE THIS AFTERNOON. WHETHER TO EXTEND
THE ADVISORY FOR THE GRAND INTO THIS AFTERNOON WILL PROBABLY BE A
LAST- MINUTE CALL AND SOMEWHAT DEPENDENT ON HOW MUCH TEMPS WARM TO
EASE THE THREAT OF ICY ROADS AND SIDEWALKS. BELIEVE THE NOONTIME
EXPIRATION OF THE WINTER HIGHLIGHT FOR THE DEBEQUE TO SILT
CORRIDOR AND THE CENTRAL CO RIVER VALLEY STILL LOOKS ON TRACK.
.SHORT TERM...(TODAY THROUGH TUESDAY)
ISSUED AT 519 AM MST MON FEB 23 2015
SNOWFALL CONTINUES ACROSS MOST OF THE SOUTHERN HALF OF THE
FORECAST AREA...AND NORTHWARD ACROSS THE I-70 CORRIDOR EARLY THIS
MORNING. ALREADY SIGNIFICANT AMOUNTS HAVE FALLEN FROM THE
UNCOMPAHGRE RIVER BASIN SOUTH TO THE NM BORDER...WITH MORE
EXPECTED THROUGH TODAY. SNOW IN THE CENTRAL VALLEYS FROM MOAB TO
GRAND JUNCTION TO EAGLE HAS BEEN MORE ON THE LIGHT SIDE. WILL DROP
THE ADVISORY FOR MOAB AND THE GRAND FLAT WITH THIS PACKAGE AS THAT
ZONE HAS RECEIVED VERY LITTLE SNOW...WITH NOT MUCH MORE EXPECTED.
HOWEVER WILL KEEP THE HIGHLIGHTS GOING FOR THE COLORADO I-70
CORRIDOR AS THOSE ZONES HAVE RECEIVED ENOUGH TO AFFECT
TRAVEL...AND MODEST AMOUNTS ARE STILL EXPECTED THROUGH THE
MORNING. HAVE ALSO OPTED TO END THE WARNINGS EARLY FOR THE
COLORADO TAVAPUTS AND THE FLATTOPS...TO COINCIDE WITH THE END
TIMING OF THESE I-70 CORRIDOR VALLEY ZONES WHICH EXPIRE AT NOON.
ON THE FLIP SIDE HAVE EXTENDED THE WARNING FOR UT ZONE 29 UNTIL
MIDNIGHT TO MATCH UP BETTER WITH THE HIGHLIGHTS FOR OTHER
SOUTHEAST UT AND SOUTHWEST CO ZONES. ALL OF SOUTHEAST UT AND
SOUTHWEST CO FROM AROUND THE LA SAL MOUNTAINS EAST TO THE
SOUTHERN SLOPES OF THE GRAND MESA AND THE WEST ELKS...AND
SOUTHWARD TO THE NM/AZ BORDERS WILL CONTINUE TO BE UNDER THE GUN
TODAY AS A MOIST AND UNSTABLE AIR MASS CONTINUES TO FLOW INTO THE
REGION. A CONVERGENT ZONE HAS DEVELOPED FROM AROUND BLANDING TO
MONTROSE AND WILL PERSIST MORE OR LESS THROUGH THE DAY. THIS IS
ALL THE RESULT OF A LOW PRESSURE CENTER THAT WILL CLOSE OFF OVER
CENTRAL CALIFORNIA TODAY...THEN MOVE INTO NORTHWEST AZ TONIGHT. AS
A RESULT A DEFORMATION ZONE WILL DEVELOP ACROSS THE SOUTHERN
PORTION OF OUR AREA AND KEEP MODERATE TO HEAVY SNOW INTO THE
EVENING OVER THE SOUTHERN ZONES. ENOUGH COOLING WILL HAVE OCCURRED
BY THIS AFTERNOON...THAT I DO NOT EXPECT SNOW TO CHANGE OVER...OR
EVEN MIX WITH TO RAIN EXCEPT POSSIBLY FOR BRIEF PERIODS IN THE
LOWEST SOUTHERN VALLEYS.
THE LOW WILL THEN MOVE INTO CENTRAL/SOUTHERN NEW MEXICO ON TUE
WITH PRECIPITATION PERSISTING INTO THE AFTERNOON OVER THE SOUTHERN
EDGE. HOWEVER SNOW INTENSITY LATE TONIGHT THROUGH TUE IS MOSTLY
EXPECTED TO BE LIGHT...ESPECIALLY WHEN COMPARED TO THE AMOUNTS
THIS STORM HAS ALREADY PRODUCED.
.LONG TERM...(TUESDAY NIGHT THROUGH SUNDAY)
ISSUED AT 519 AM MST MON FEB 23 2015
SNOW FINALLY DIMINISHES ACROSS THE SOUTH AS THE LATEST STORM IS
FORCED TO THE SOUTHEAST TUESDAY NIGHT. HOWEVER...EXPECT SOME
LIGHT SNOW TO BEGIN ACROSS THE NORTHERN COLORADO MOUNTAINS LATER
IN THE NIGHT AS MOISTURE AHEAD OF AN APPROACHING SHORTWAVE TROUGH
TO THE NORTHWEST SWEEPS OVER THE AREA. EXPECT SNOW TO INCREASE AND
SPREAD INTO THE SOUTHERN MOUNTAINS AND ADJACENT VALLEYS WEDNESDAY
AND WEDNESDAY NIGHT AS THE SHORTWAVE TROUGH PASSES SOUTHEASTWARD
ACROSS THE AREA. IN FACT...A SERIES OF WAVES WILL PASS THROUGH THE
AREA DURING THE REMAINDER OF THE WEEK...MAINLY IMPACTING THE
COLORADO DIVIDE MOUNTAINS. A BIT DIFFICULT TO TIME THESE
DISTURBANCES THIS FAR OUT BUT GOES WITHOUT SAYING THAT THE PATTERN
HAS SHIFTED TO A MORE PROGRESSIVE...WETTER...AND COOLER REGIME.
IN FACT...FOR THOSE ALREADY DIGGING OUT ACROSS SOUTHEAST UTAH AND
SOUTHWEST COLORADO...MODELS ARE HINTING AT THE POTENTIAL FOR ANOTHER
SIGNIFICANT SNOW EVENT THIS WEEKEND. DETAILS A BIT SKETCHY AT THIS
POINT AS GFS AND EC NOT ENTIRELY ON THE SAME PAGE.
&&
.SHORT TERM...(TODAY THROUGH TUESDAY)
ISSUED AT 519 AM MST MON FEB 23 2015
SNOWFALL CONTINUES ACROSS MOST OF THE SOUTHERN HALF OF THE
FORECAST AREA...AND NORTHWARD ACROSS THE I-70 CORRIDOR EARLY THIS
MORNING. ALREADY SIGNIFICANT AMOUNTS HAVE FALLEN FROM THE
UNCOMPAHGRE RIVER BASIN SOUTH TO THE NM BORDER...WITH MORE
EXPECTED THROUGH TODAY. SNOW IN THE CENTRAL VALLEYS FROM MOAB TO
GRAND JUNCTION TO EAGLE HAS BEEN MORE ON THE LIGHT SIDE. WILL DROP
THE ADVISORY FOR MOAB AND THE GRAND FLAT WITH THIS PACKAGE AS THAT
ZONE HAS RECEIVED VERY LITTLE SNOW...WITH NOT MUCH MORE EXPECTED.
HOWEVER WILL KEEP THE HIGHLIGHTS GOING FOR THE COLORADO I-70
CORRIDOR AS THOSE ZONES HAVE RECEIVED ENOUGH TO AFFECT
TRAVEL...AND MODEST AMOUNTS ARE STILL EXPECTED THROUGH THE
MORNING. HAVE ALSO OPTED TO END THE WARNINGS EARLY FOR THE
COLORADO TAVAPUTS AND THE FLATTOPS...TO COINCIDE WITH THE END
TIMING OF THESE I-70 CORRIDOR VALLEY ZONES WHICH EXPIRE AT NOON.
ON THE FLIP SIDE HAVE EXTENDED THE WARNING FOR UT ZONE 29 UNTIL
MIDNIGHT TO MATCH UP BETTER WITH THE HIGHLIGHTS FOR OTHER
SOUTHEAST UT AND SOUTHWEST CO ZONES. ALL OF SOUTHEAST UT AND
SOUTHWEST CO FROM AROUND THE LA SAL MOUNTAINS EAST TO THE
SOUTHERN SLOPES OF THE GRAND MESA AND THE WEST ELKS...AND
SOUTHWARD TO THE NM/AZ BORDERS WILL CONTINUE TO BE UNDER THE GUN
TODAY AS A MOIST AND UNSTABLE AIR MASS CONTINUES TO FLOW INTO THE
REGION. A CONVERGENT ZONE HAS DEVELOPED FROM AROUND BLANDING TO
MONTROSE AND WILL PERSIST MORE OR LESS THROUGH THE DAY. THIS IS
ALL THE RESULT OF A LOW PRESSURE CENTER THAT WILL CLOSE OFF OVER
CENTRAL CALIFORNIA TODAY...THEN MOVE INTO NORTHWEST AZ TONIGHT. AS
A RESULT A DEFORMATION ZONE WILL DEVELOP ACROSS THE SOUTHERN
PORTION OF OUR AREA AND KEEP MODERATE TO HEAVY SNOW INTO THE
EVENING OVER THE SOUTHERN ZONES. ENOUGH COOLING WILL HAVE OCCURRED
BY THIS AFTERNOON...THAT I DO NOT EXPECT SNOW TO CHANGE OVER...OR
EVEN MIX WITH TO RAIN EXCEPT POSSIBLY FOR BRIEF PERIODS IN THE
LOWEST SOUTHERN VALLEYS.
THE LOW WILL THEN MOVE INTO CENTRAL/SOUTHERN NEW MEXICO ON TUE
WITH PRECIPITATION PERSISTING INTO THE AFTERNOON OVER THE SOUTHERN
EDGE. HOWEVER SNOW INTENSITY LATE TONIGHT THROUGH TUE IS MOSTLY
EXPECTED TO BE LIGHT...ESPECIALLY WHEN COMPARED TO THE AMOUNTS
THIS STORM HAS ALREADY PRODUCED.
.LONG TERM...(TUESDAY NIGHT THROUGH SUNDAY)
ISSUED AT 519 AM MST MON FEB 23 2015
SNOW FINALLY DIMINISHES ACROSS THE SOUTH AS THE LATEST STORM IS
FORCED TO THE SOUTHEAST TUESDAY NIGHT. HOWEVER...EXPECT SOME
LIGHT SNOW TO BEGIN ACROSS THE NORTHERN COLORADO MOUNTAINS LATER
IN THE NIGHT AS MOISTURE AHEAD OF AN APPROACHING SHORTWAVE TROUGH
TO THE NORTHWEST SWEEPS OVER THE AREA. EXPECT SNOW TO INCREASE AND
SPREAD INTO THE SOUTHERN MOUNTAINS AND ADJACENT VALLEYS WEDNESDAY
AND WEDNESDAY NIGHT AS THE SHORTWAVE TROUGH PASSES SOUTHEASTWARD
ACROSS THE AREA. IN FACT...A SERIES OF WAVES WILL PASS THROUGH THE
AREA DURING THE REMAINDER OF THE WEEK...MAINLY IMPACTING THE
COLORADO DIVIDE MOUNTAINS. A BIT DIFFICULT TO TIME THESE
DISTURBANCES THIS FAR OUT BUT GOES WITHOUT SAYING THAT THE PATTERN
HAS SHIFTED TO A MORE PROGRESSIVE...WETTER...AND COOLER REGIME.
IN FACT...FOR THOSE ALREADY DIGGING OUT ACROSS SOUTHEAST UTAH AND
SOUTHWEST COLORADO...MODELS ARE HINTING AT THE POTENTIAL FOR ANOTHER
SIGNIFICANT SNOW EVENT THIS WEEKEND. DETAILS A BIT SKETCHY AT THIS
POINT AS GFS AND EC NOT ENTIRELY ON THE SAME PAGE.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON)
ISSUED AT 1013 AM MST MON FEB 23 2015
THIS WINTER STORM IS SLOWLY WINDING DOWN BUT PLENTY OF AVIATION
CONCERNS WILL CONTINUE OVER THE NEXT 24 HOURS. SNOW LOOKS TO
CONTINUE ACROSS SOUTHWEST COLORADO TO SOUTHEAST UTAH...WITH
MVFR/IFR IMPACTS TO THE SOUTHERN FORECAST TERMINALS A HIGH
PROBABILITY TO CONTINUE THROUGH TUESDAY. IMPROVEMENT ALONG THE
WESTERN INTERSTATE 70 CORRIDOR SHOULD OCCUR AFTER 20Z WITH IFR
CONDITIONS HANGING IN AT CNY AND GJT LATE THIS MORNING AND VFR IN
THE COLORADO AND EAGLE VALLEYS TO THE EAST. OBSCURATION OF THE
TERRAIN WILL PERSIST OVER THE NEXT 24 HOURS AS WELL.
&&
.GJT WATCHES/WARNINGS/ADVISORIES...
CO...WINTER STORM WARNING UNTIL MIDNIGHT MST TONIGHT FOR COZ009>012-
014-017>023.
UT...WINTER STORM WARNING UNTIL MIDNIGHT MST TONIGHT FOR UTZ022-029.
WINTER STORM WARNING UNTIL 6 AM MST TUESDAY FOR UTZ028.
&&
$$
UPDATE...JAD
SHORT TERM...EH
LONG TERM...NL
AVIATION...TGJT
AREA FORECAST DISCUSSION
NWS GRAND JUNCTION CO
1015 AM MST MON FEB 23 2015
.UPDATE...
ISSUED AT 1013 AM MST MON FEB 23 2015
SNOW REMAINED WIDESPREAD ACROSS SW CO THIS MORNING...PRETTY MUCH
FROM GRAND JCT AND ASPEN SOUTH. OBSERVATIONS INDICATING THE HEAVIER
SNOW FROM ABOUT MONTROSE/PARADOX VALLEY SOUTH. SNOW ALSO NOTED
ACROSS MUCH OF SE UT. THIS UNDER A BROAD AREA OF UPPER DIVERGENCE/
LOWER (MOISTURE)CONVERGENCE PLUS ISENTROPIC UPGLIDE AND A MOIST
DENDRITIC SNOW GROWTH ZONE. EARLY LOOK AT THIS MORNING`S MODELS SHOW
THE HEAVIER SNOW BAND SLOWLY SHIFTNIG SOUTH WITH SOME REDUCTION IN
UPPER LEVEL SUPPORT AS THE UPPER JET ACROSS NRN AZ AND NRN NM
PROGRESSES EASTWARD. WINTER STORM WARNINGS CONTINUE FOR SE UT AND
SW CO. STILL ASSESSING WHETHER OR NOT TO EXTEND THE HIGHLIGHTS
INTO TUE FOR AT LEAST THE AREAS FROM THE ABAJOS AND SAN JUANS
SOUTH.
LIGHT SNOW IN THE GRAND VALLEY THIS MORNING BELIEVED TO BE MAINLY
DUE TO MOISTURE IN SSW FLOW OVERRUNNING COLD AIR TRAPPED IN THE
VALLEY. NAM12 AND HIGH RESOLUTION RAP MODELS SUGGEST THIS MOIST
OVERRUNNING DECREASES FOR THE GRAND VALLEY THIS AFTERNOON AS FLOW
ALOFT BEGINS TO TAKE ON A MORE NORTHERLY TACK. THESE MODELS ALSO
SHOW ONLY LIGHT SNOW ACCUMS THERE THIS AFTERNOON. WHETHER TO EXTEND
THE ADVISORY FOR THE GRAND INTO THIS AFTERNOON WILL PROBABLY BE A
LAST- MINUTE CALL AND SOMEWHAT DEPENDENT ON HOW MUCH TEMPS WARM TO
EASE THE THREAT OF ICY ROADS AND SIDEWALKS. BELIEVE THE NOONTIME
EXPIRATION OF THE WINTER HIGHLIGHT FOR THE DEBEQUE TO SILT
CORRIDOR AND THE CENTRAL CO RIVER VALLEY STILL LOOKS ON TRACK.
.SHORT TERM...(TODAY THROUGH TUESDAY)
ISSUED AT 519 AM MST MON FEB 23 2015
SNOWFALL CONTINUES ACROSS MOST OF THE SOUTHERN HALF OF THE
FORECAST AREA...AND NORTHWARD ACROSS THE I-70 CORRIDOR EARLY THIS
MORNING. ALREADY SIGNIFICANT AMOUNTS HAVE FALLEN FROM THE
UNCOMPAHGRE RIVER BASIN SOUTH TO THE NM BORDER...WITH MORE
EXPECTED THROUGH TODAY. SNOW IN THE CENTRAL VALLEYS FROM MOAB TO
GRAND JUNCTION TO EAGLE HAS BEEN MORE ON THE LIGHT SIDE. WILL DROP
THE ADVISORY FOR MOAB AND THE GRAND FLAT WITH THIS PACKAGE AS THAT
ZONE HAS RECEIVED VERY LITTLE SNOW...WITH NOT MUCH MORE EXPECTED.
HOWEVER WILL KEEP THE HIGHLIGHTS GOING FOR THE COLORADO I-70
CORRIDOR AS THOSE ZONES HAVE RECEIVED ENOUGH TO AFFECT
TRAVEL...AND MODEST AMOUNTS ARE STILL EXPECTED THROUGH THE
MORNING. HAVE ALSO OPTED TO END THE WARNINGS EARLY FOR THE
COLORADO TAVAPUTS AND THE FLATTOPS...TO COINCIDE WITH THE END
TIMING OF THESE I-70 CORRIDOR VALLEY ZONES WHICH EXPIRE AT NOON.
ON THE FLIP SIDE HAVE EXTENDED THE WARNING FOR UT ZONE 29 UNTIL
MIDNIGHT TO MATCH UP BETTER WITH THE HIGHLIGHTS FOR OTHER
SOUTHEAST UT AND SOUTHWEST CO ZONES. ALL OF SOUTHEAST UT AND
SOUTHWEST CO FROM AROUND THE LA SAL MOUNTAINS EAST TO THE
SOUTHERN SLOPES OF THE GRAND MESA AND THE WEST ELKS...AND
SOUTHWARD TO THE NM/AZ BORDERS WILL CONTINUE TO BE UNDER THE GUN
TODAY AS A MOIST AND UNSTABLE AIR MASS CONTINUES TO FLOW INTO THE
REGION. A CONVERGENT ZONE HAS DEVELOPED FROM AROUND BLANDING TO
MONTROSE AND WILL PERSIST MORE OR LESS THROUGH THE DAY. THIS IS
ALL THE RESULT OF A LOW PRESSURE CENTER THAT WILL CLOSE OFF OVER
CENTRAL CALIFORNIA TODAY...THEN MOVE INTO NORTHWEST AZ TONIGHT. AS
A RESULT A DEFORMATION ZONE WILL DEVELOP ACROSS THE SOUTHERN
PORTION OF OUR AREA AND KEEP MODERATE TO HEAVY SNOW INTO THE
EVENING OVER THE SOUTHERN ZONES. ENOUGH COOLING WILL HAVE OCCURRED
BY THIS AFTERNOON...THAT I DO NOT EXPECT SNOW TO CHANGE OVER...OR
EVEN MIX WITH TO RAIN EXCEPT POSSIBLY FOR BRIEF PERIODS IN THE
LOWEST SOUTHERN VALLEYS.
THE LOW WILL THEN MOVE INTO CENTRAL/SOUTHERN NEW MEXICO ON TUE
WITH PRECIPITATION PERSISTING INTO THE AFTERNOON OVER THE SOUTHERN
EDGE. HOWEVER SNOW INTENSITY LATE TONIGHT THROUGH TUE IS MOSTLY
EXPECTED TO BE LIGHT...ESPECIALLY WHEN COMPARED TO THE AMOUNTS
THIS STORM HAS ALREADY PRODUCED.
.LONG TERM...(TUESDAY NIGHT THROUGH SUNDAY)
ISSUED AT 519 AM MST MON FEB 23 2015
SNOW FINALLY DIMINISHES ACROSS THE SOUTH AS THE LATEST STORM IS
FORCED TO THE SOUTHEAST TUESDAY NIGHT. HOWEVER...EXPECT SOME
LIGHT SNOW TO BEGIN ACROSS THE NORTHERN COLORADO MOUNTAINS LATER
IN THE NIGHT AS MOISTURE AHEAD OF AN APPROACHING SHORTWAVE TROUGH
TO THE NORTHWEST SWEEPS OVER THE AREA. EXPECT SNOW TO INCREASE AND
SPREAD INTO THE SOUTHERN MOUNTAINS AND ADJACENT VALLEYS WEDNESDAY
AND WEDNESDAY NIGHT AS THE SHORTWAVE TROUGH PASSES SOUTHEASTWARD
ACROSS THE AREA. IN FACT...A SERIES OF WAVES WILL PASS THROUGH THE
AREA DURING THE REMAINDER OF THE WEEK...MAINLY IMPACTING THE
COLORADO DIVIDE MOUNTAINS. A BIT DIFFICULT TO TIME THESE
DISTURBANCES THIS FAR OUT BUT GOES WITHOUT SAYING THAT THE PATTERN
HAS SHIFTED TO A MORE PROGRESSIVE...WETTER...AND COOLER REGIME.
IN FACT...FOR THOSE ALREADY DIGGING OUT ACROSS SOUTHEAST UTAH AND
SOUTHWEST COLORADO...MODELS ARE HINTING AT THE POTENTIAL FOR ANOTHER
SIGNIFICANT SNOW EVENT THIS WEEKEND. DETAILS A BIT SKETCHY AT THIS
POINT AS GFS AND EC NOT ENTIRELY ON THE SAME PAGE.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON)
ISSUED AT 1013 AM MST MON FEB 23 2015
THIS WINTER STORM IS SLOWLY WINDING DOWN BUT PLENTY OF AVIATION
CONCERNS WILL CONTINUE OVER THE NEXT 24 HOURS. SNOW LOOKS TO
CONTINUE ACROSS SOUTHWEST COLORADO TO SOUTHEAST UTAH...WITH
MVFR/IFR IMPACTS TO THE SOUTHERN FORECAST TERMINALS A HIGH
PROBABILITY TO CONTINUE THROUGH TUESDAY. IMPROVEMENT ALONG THE
WESTERN INTERSTATE 70 CORRIDOR SHOULD OCCUR AFTER 20Z WITH IFR
CONDITIONS HANGING IN AT CNY AND GJT LATE THIS MORNING AND VFR IN
THE COLORADO AND EAGLE VALLEYS TO THE EAST. OBSCURATION OF THE
TERRAIN WILL PERSIST OVER THE NEXT 24 HOURS AS WELL.
&&
.GJT WATCHES/WARNINGS/ADVISORIES...
CO...WINTER STORM WARNING UNTIL MIDNIGHT MST TONIGHT FOR COZ009>012-
014-017>023.
WINTER STORM WARNING UNTIL NOON MST TODAY FOR COZ003-007-008-013.
WINTER WEATHER ADVISORY UNTIL NOON MST TODAY FOR COZ006.
UT...WINTER STORM WARNING UNTIL MIDNIGHT MST TONIGHT FOR UTZ022-029.
WINTER STORM WARNING UNTIL 6 AM MST TUESDAY FOR UTZ028.
&&
$$
SHORT TERM...EH
LONG TERM...NL
AVIATION...TGJT
AREA FORECAST DISCUSSION
NWS SHREVEPORT LA
100 PM CST MON FEB 23 2015
.AVIATION...
FOR THE 23/18Z TAFS...WINTRY MIX OF PRECIPITATION WILL CONTINUE TO
AFFECT OUR AREA TERMINALS THROUGH THE FIRST HALF OF THE TAF PERIOD
EXCEPT LFK WHERE IT APPEARS WE MAY STAY WITH JUST LIGHT RAIN UNTIL
THE OVERNIGHT HOURS. CIGS/VSBYS VARY WIDELY BUT ARE MOSTLY MVFR/IFR
AND WILL REMAIN SO THROUGH THE TAF PERIOD. PRECIPITATION WILL TAPER
OFF FROM WEST TO EAST THROUGH THE EVENING AND OVERNIGHT HOURS BUT
CIGS WILL STILL REMAIN MOSTLY IFR. WINDS WILL MAINTAIN A NORTHERLY
COMPONENT AND BEGIN TO DECREASE AFTER 24/00Z TO AROUND 5 KTS. /19/
&&
.PREV DISCUSSION... /ISSUED 1047 AM CST MON FEB 23 2015/
DISCUSSION...
FREEZING LINE CURRENTLY ALONG THE INTERSTATE 20 CORRIDOR FROM
JACKSONVILLE TEXAS TO MONROE LOUISIANA. PRECIPITATION ALONG AND
NORTH OF INTERSTATE 20 IN THE FORM OF SNOW ACROSS SOUTHEAST
OKLAHOMA...AND A MIX OF SLEET/FREEZING RAIN/RAIN ELSEWHERE.
TEMPERATURES CONTINUING TO FALL AREAWIDE. LOOKS LIKE THIS PUSH OF
PRECIPITATION MAY BE THE MAIN EVENT. HRRR AND GFS MODELS TEND TO
SUGGEST A SECOND SURGE OF MOISTURE COMING UP FROM SOUTHEAST TEXAS
LATER THIS AFTERNOON...WHILE NAM REMAINS THE OUTLIER WITH
PRECIPITATION CONTINUING ACROSS THE SOUTHEAST OKLAHOMA AND SOUTHERN
ARKANSAS. FOR THIS UPDATE...WILL MAINTAIN WARNINGS AND ADVISORIES
AS IS. ONLY CHANGE WAS TO DECREASE POPS ACROSS DEEP EAST TEXAS AND
WEST CENTRAL LOUISIANA BASED ON CURRENT RADAR TRENDS. /05/
&&
.PRELIMINARY POINT TEMPS/POPS...
SHV 27 38 34 41 30 / 60 30 40 60 10
MLU 27 37 34 39 29 / 60 30 40 60 10
DEQ 24 37 30 41 29 / 50 20 20 50 10
TXK 26 37 31 41 28 / 50 20 20 60 10
ELD 24 38 31 40 27 / 60 20 20 60 10
TYR 27 37 33 41 32 / 60 20 40 60 10
GGG 28 39 33 41 31 / 60 20 40 60 10
LFK 29 41 34 41 33 / 60 30 40 60 10
&&
.SHV WATCHES/WARNINGS/ADVISORIES...
AR...WINTER STORM WARNING UNTIL 9 PM CST THIS EVENING FOR THE
FOLLOWING ZONES: ARZ070>072.
WINTER WEATHER ADVISORY UNTIL 9 PM CST THIS EVENING FOR THE
FOLLOWING ZONES: ARZ050-051-059>061-073.
LA...WINTER STORM WARNING UNTIL 9 PM CST THIS EVENING FOR THE
FOLLOWING ZONES: LAZ001>003.
WINTER WEATHER ADVISORY UNTIL 9 PM CST THIS EVENING FOR THE
FOLLOWING ZONES: LAZ004>006-010>014-017>022.
OK...WINTER WEATHER ADVISORY UNTIL 9 PM CST THIS EVENING FOR THE
FOLLOWING ZONES: OKZ077.
TX...WINTER STORM WARNING UNTIL 9 PM CST THIS EVENING FOR THE
FOLLOWING ZONES: TXZ096-097-108>112-124>126-136>138.
WINTER WEATHER ADVISORY UNTIL 9 PM CST THIS EVENING FOR THE
FOLLOWING ZONES: TXZ149>153-165>167.
&&
$$
19
AREA FORECAST DISCUSSION
NWS SHREVEPORT LA
1047 AM CST MON FEB 23 2015
.DISCUSSION...
FREEZING LINE CURRENTLY ALONG THE INTERSTATE 20 CORRIDOR FROM
JACKSONVILLE TEXAS TO MONROE LOUISIANA. PRECIPITATION ALONG AND
NORTH OF INTERSTATE 20 IN THE FORM OF SNOW ACROSS SOUTHEAST
OKLAHOMA...AND A MIX OF SLEET/FREEZING RAIN/RAIN ELSEWHERE.
TEMPERATURES CONTINUING TO FALL AREAWIDE. LOOKS LIKE THIS PUSH OF
PRECIPITATION MAY BE THE MAIN EVENT. HRRR AND GFS MODELS TEND TO
SUGGEST A SECOND SURGE OF MOISTURE COMING UP FROM SOUTHEAST TEXAS
LATER THIS AFTERNOON...WHILE NAM REMAINS THE OUTLIER WITH
PRECIPITATION CONTINUING ACROSS THE SOUTHEAST OKLAHOMA AND SOUTHERN
ARKANSAS. FOR THIS UPDATE...WILL MAINTAIN WARNINGS AND ADVISORIES
AS IS. ONLY CHANGE WAS TO DECREASE POPS ACROSS DEEP EAST TEXAS AND
WEST CENTRAL LOUISIANA BASED ON CURRENT RADAR TRENDS. /05/
&&
.PRELIMINARY POINT TEMPS/POPS...
SHV 32 27 38 34 41 / 80 60 30 40 60
MLU 30 27 37 34 39 / 80 60 30 40 60
DEQ 28 24 37 30 41 / 80 50 20 20 50
TXK 30 26 37 31 41 / 80 50 20 20 60
ELD 28 24 38 31 40 / 80 60 20 20 60
TYR 32 27 37 33 41 / 80 60 20 40 60
GGG 33 28 39 33 41 / 80 60 20 40 60
LFK 36 29 41 34 41 / 80 60 30 40 60
&&
.SHV WATCHES/WARNINGS/ADVISORIES...
AR...WINTER STORM WARNING UNTIL 9 PM CST THIS EVENING FOR THE
FOLLOWING ZONES: ARZ070>072.
WINTER WEATHER ADVISORY UNTIL 9 PM CST THIS EVENING FOR THE
FOLLOWING ZONES: ARZ050-051-059>061-073.
LA...WINTER STORM WARNING UNTIL 9 PM CST THIS EVENING FOR THE
FOLLOWING ZONES: LAZ001>003.
WINTER WEATHER ADVISORY UNTIL 9 PM CST THIS EVENING FOR THE
FOLLOWING ZONES: LAZ004>006-010>014-017>022.
OK...WINTER WEATHER ADVISORY UNTIL 9 PM CST THIS EVENING FOR THE
FOLLOWING ZONES: OKZ077.
TX...WINTER STORM WARNING UNTIL 9 PM CST THIS EVENING FOR THE
FOLLOWING ZONES: TXZ096-097-108>112-124>126-136>138.
WINTER WEATHER ADVISORY UNTIL 9 PM CST THIS EVENING FOR THE
FOLLOWING ZONES: TXZ149>153-165>167.
&&
$$
05/05
AREA FORECAST DISCUSSION
NWS CARIBOU ME
344 PM EST MON FEB 23 2015
.SYNOPSIS...
COLD HIGH PRESSURE WILL BUILD IN FROM THE WEST TONIGHT THEN SLIDE
SOUTH OF THE REGION ON TUESDAY. A TROUGH OF LOW PRESSURE WILL
APPROACH TUESDAY NIGHT. LOW PRESSURE WILL DEVELOP SOUTH OF THE AREA
EARLY WEDNESDAY AND TRACK INTO THE MARITIMES WEDNESDAY AFTERNOON.
&&
.NEAR TERM /THROUGH TUESDAY/...
THE MAIN CHALLENGES THIS TERM WILL BE STREAMERS OFF THE ST.
LAWRENCE, WIND CHILLS AND OF COURSE TEMPERATURES.
LATEST VISIBLE SATELLITE IMAGERY SHOWED CLOUDS MOVING E OFF THE ST
LAWRENCE. LLVL CONVERGENCE SHOWING UP ON THE SURFACE ANALYSIS
ACROSS FAR NORTHERN MAINE(THE CROWN MOST PARTICULARLY. PERIODS OF
LIGHT SNOW FOR NW AND NE AROOSTOOK COUNTY COULD BRING AN INCH OF
SNOW BY THIS EVENING AND THEN WINDS BEGIN TO LET UP. MODEL SOUNDINGS
SUPPORT DEEP MOISTURE THROUGH 800MBS W/SOME WEAK FORCING ALOFT.
DECIDED TO BOOST POPS UP ACROSS THE FAR NORTHERN AREAS(60-80%) TO
ACCOUNT FOR THE SNOW. THE RAP/NAM12 AND HRRR MESOSCALE MODELS
WERE DOING WELL W/THIS SETUP. AREAS OF BLOWING SNOW A FACTOR INTO
THE EVENING AND WILL CONTINUE THAT WORDING IN THE FORECAST THROUGH
9 PM. HISTORICALLY, CLOUDS AND STREAMERS BREAK UP AS THE WINDS
SHIFT MORE TO THE WEST AND THE AIRMASS DRIES OUT. THIS IS SHOWN TO
BE THE CASE LATER THIS EVENING. FURTHER S, BASICALLY CLEAR SKIES
W/SOME SCT CLOUDS FROM TIME TO TIME. THIS WILL LEAD TO SOME VERY
COLD IF NOT BITTERLY COLD TEMPERATURES OVERNIGHT INTO TUESDAY
MORNING. WE ARE TALKING 15 TO 25 BELOW ACROSS THE NORTH AND WEST
AND PERHAPS 30 BELOW IN THE SHELTERED AREAS. CENTRAL AND DOWNEAST
WILL 10 TO 15 BELOW EVEN TO THE COAST. DANGEROUS WIND CHILLS ARE
ON THE DOCKET THROUGH EARLY TUESDAY APPROACHING WARNING
CRITERIA(-35F) ACROSS THE NORTHERN AND WESTERN AREAS. ATTM,
DECIDED TO STAY W/WIND CHILL ADVISORIES AS THE WINDOW LOOKS TO BE
SHORT(<3 HRS) FOR WIND CHILLS TO HIT <-35F AND WINDS ARE FORECAST
TO DROP OFF BELOW 10 MPH.
TUESDAY WILL START OUT SUNNY AND VERY COLD W/HIGH PRES RIDGING
INTO THE REGION. THE RIDGE AXIS IF FORECAST TO SLIDE THROUGH THE
REGION QUICKLY DURING THE DAY W/CLOUDS ON THE INCREASE BY THE
AFTERNOON. DAYTIME TEMPERATURES ACROSS THE NORTHERN 1/2 OF THE CWA
IN THE SINGLE NUMBER WHILE CENTRAL AND DOWNEAST WILL SEE 10 TO 15
AT BEST AND THE WARMER TEMPERATURES TOWARD THE COAST.
&&
.SHORT TERM /TUESDAY NIGHT THROUGH THURSDAY/...
A TROUGH OF LOW PRESSURE WILL APPROACH FROM THE GREAT LAKES TUESDAY
NIGHT. A SMALL AREA OF LOW PRESSURE WILL DEVELOP ALONG THE
SOUTHEASTERN EDGE OF THE TROUGH, OFF THE SOUTHERN NEW ENGLAND COAST,
LATE TUESDAY NIGHT. THE FORECAST CHALLENGE WILL BE IN DETERMINING
HOW QUICKLY THIS LOW DEVELOPS AND HOW CLOSE THE LOW WILL TRACK TO
OUR REGION ON WEDNESDAY. LATEST FORECAST GUIDANCE CARRIES THE LOW
INTO THE GULF OF MAINE WEDNESDAY MORNING SPREADING SNOW ACROSS
DOWNEAST AREAS VERY EARLY WEDNESDAY MORNING THEN ON UP ACROSS EAST
CENTRAL AND NORTHEASTERN AREAS LATER WEDNESDAY MORNING. THIS IS A
SMALL, FAST MOVING LOW AND APPEARS WILL NOT BE IN THE AREA LONG
ENOUGH TO PRODUCE HEAVY SNOW ACCUMULATIONS. A LIGHT TO MODERATE
SNOWFALL OF 3 TO 5 INCHES CURRENTLY APPEARS MOST LIKELY FROM
DOWNEAST AREAS NORTHWARD INTO EASTERN AREAS OF NORTHERN MAINE
THROUGH WEDNESDAY MIDDAY BEFORE THE LOW LIFTS OUT. THE NAM...GFS
AND ECMWF ALL OFFER SIMILAR SOLUTIONS AND HAVE BEEN CONSISTENT
WITH PREVIOUS RUNS SHOWING JUST A QUICK SNOWFALL OF MODERATE
INTENSITY ACROSS EASTERN AREAS WITH THIS SYSTEM. THE LOW WILL
CONTINUE TO INTENSIFY WEDNESDAY AFTERNOON BUT WILL BE QUICK TO
LIFT NORTHEAST AND AWAY THROUGH THE MARITIMES AS DRY AND BREEZY
WEATHER FOLLOWS. SNOW SHOULD TAPER OFF LATE WEDNESDAY MORNING
DOWNEAST AND WEDNESDAY AFTERNOON ACROSS THE NORTHEAST. HIGH
PRESSURE WILL THEN BRING DRY AND COLD CONDITIONS WEDNESDAY NIGHT
INTO THURSDAY.
&&
.LONG TERM /THURSDAY NIGHT THROUGH MONDAY/...
A LARGE AREA OF HIGH PRESSURE PUSHING INTO THE EAST WILL MAINTAIN
DRY WEATHER THURSDAY NIGHT THROUGH THE COMING WEEKEND. TEMPS AHEAD
OF THE HIGH WILL BE WELL BELOW NORMAL INTO SATURDAY, THEN WARM UP
CLOSER TO NORMAL LATE IN THE WEEKEND IN THE RETURN FLOW BEHIND THE
HIGH ON SUNDAY. CLOUDS WILL INCREASE ON SUNDAY AND SOME SNOW IS
POSSIBLE SUNDAY NIGHT INTO MONDAY AS A TROUGH AND WEAK FRONTAL
SYSTEM PUSH IN FROM THE WEST. AT THIS TIME THE SYSTEM SUNDAY NIGHT
INTO MONDAY LOOKS LIKE A PROGRESSIVE OPEN WAVE WITH ONLY LIGHT TO
MODERATE SNOW EXPECTED. DRIER CONDITIONS SHOULD RETURN BEHIND A COLD
FRONT LATER MONDAY INTO MONDAY NIGHT.
&&
.AVIATION /19Z MONDAY THROUGH SATURDAY/...
NEAR TERM: MVFR W/IFR VSBYS THROUGH EARLY EVENING ACROSS THE
NORTHERN TERMINALS(NORTH OF KHUL) DUE TO THE STREAMERS OFF THE ST.
LAWRENCE. FURTHER SOUTH, GENERALLY VFR. CLOUDS AND LIGHT SNOW
ACROSS THE NORTH WILL END LATER THIS EVENING AS WINDS DROP OFF
LEADING TO VFR. IT LOOKS LIKE VFR FOR THE ENTIRE AVIATION SECTOR
FOR TUESDAY.
SHORT TERM: VFR CONDITIONS TUESDAY NIGHT WILL LOWER TO MVFR THEN
IFR VERY LATE AT NIGHT. IFR CONDITIONS IN SNOW ARE EXPECTED
WEDNESDAY MORNING. CONDITIONS MAY IMPROVE TO VFR DOWNEAST
WEDNESDAY AFTERNOON AND MVFR ACROSS THE NORTH WEDNESDAY AFTERNOON.
MAINLY VFR CONDITIONS ARE EXPECTED WEDNESDAY NIGHT AND THURSDAY
WITH THE POSSIBLE EXCEPTION OF SOME MVFR CONDITIONS IN THE ST JOHN
VALLEY. VFR CONDITIONS ARE THEN EXPECTED THURSDAY NIGHT THROUGH
SATURDAY.
&&
.MARINE...
NEAR TERM: WINDS ARE NOW HITTING GALE FORCE(35 KTS) ESPECIALLY
OVER THE OUTER ZONES AS THE CAA IS HITTING IN EARNEST. WINDS WILL
INCREASE FOR A WHILE THIS EVENING W/GUSTS TO 40 KTS. THE NAM12 WAS
DOING WELL W/THE CURRENT SETUP. WINDS WILL START DROPPING OFF
LATER TONIGHT AS HIGH PRES TO THE SW RIDGES EASTWARD. GALE WARNING
WILL REMAIN THROUGH TUESDAY MORNING. EVENING CREW CAN ASSESS THIS
FURTHER W/THE LATER GUIDANCE. HEAVY FREEZING SPRAY EXPECTED
TONIGHT INTO EARLY TUESDAY THE WARNING IS UP FOR HEAVY ICING
POTENTIAL. SEAS ARE COMING UP BUT WERE SLOWER TO RESPOND. SEAS
SHOULD TOP OUT AROUND 8 FT OVER THE OUTER ZONES THIS EVENING AND
THEN BEGIN TO SUBSIDE LATER TONIGHT AS WINDS DROP OFF.
SHORT TERM: AN SCA MAY BE NEEDED LATE TUESDAY NIGHT THROUGH
WEDNESDAY AS LOW PRESSURE LIFTS ACROSS THE WATERS. HIGH PRESSURE
BUILDING OVER THE AREA SHOULD BRING MAINLY RELATIVELY LIGHT WINDS
LATE THIS WEEKEND INTO THE COMING WEEKEND.
&&
.CAR WATCHES/WARNINGS/ADVISORIES...
ME...WIND CHILL ADVISORY UNTIL 10 AM EST TUESDAY FOR MEZ001>006-010-
011-031-032.
WIND CHILL ADVISORY FROM 7 PM THIS EVENING TO 7 AM EST TUESDAY
FOR MEZ015>017-029-030.
MARINE...HEAVY FREEZING SPRAY WARNING UNTIL 7 AM EST TUESDAY FOR
ANZ050>052.
GALE WARNING UNTIL 4 AM EST TUESDAY FOR ANZ050>052.
&&
$$
NEAR TERM...HEWITT
SHORT TERM...BLOOMER
LONG TERM...BLOOMER
AVIATION...HEWITT/BLOOMER
MARINE...HEWITT/BLOOMER
AREA FORECAST DISCUSSION
NWS CARIBOU ME
1225 PM EST MON FEB 23 2015
.SYNOPSIS...
AN ARCTIC FRONT WILL CROSS THE AREA THIS AFTERNOON. HIGH PRESSURE
WILL BUILD ACROSS NORTHERN NEW ENGLAND TONIGHT AND WILL MOVE EAST
TUESDAY. DEVELOPING LOW PRESSURE FROM THE WEST WILL CROSS THE AREA
WEDNESDAY THEN MOVE TOWARD THE NORTHERN MARITIMES WEDNESDAY NIGHT.
&&
.NEAR TERM /THROUGH TONIGHT/...
1215 PM UPDATE...STREAMER BANDS CONTINUE OFF THE ST. LAWRENCE
MOVING ACROSS THE CROWN OF MAINE. THE MOST PROMINENT BAND WAS
ACROSS THE ST. JOHN VALLEY UP AROUND THE FRENCHVILLE-MADAWASKA
REGION. THE LATEST RUN OF THE RAP MODEL AND HRRR CONTINUE TO
DEPICT SOME BANDS HANGING ON INTO THE AFTERNOON ACROSS NORTHERN
MAINE AND SLIDING SE IN THE CARIBOU-PRESQUE ISLE REGION. SNOW
RATIOS W/THESE BANDS ARE HIGH(20-25:1) YIELDING CLOSE TO AN INCH
IN THE HEAVIER BANDS. THE BANDS SHOULD BEGIN TO WEAKEN THIS
EVENING AS WINDS START SETTLING DOWN AND THE DIRECTION SHIFTS
MORE TO A WNW DIRECTION SHUTTING DOWN THE TRAJECTORY FROM THE ST.
LAWRENCE. AREAS OF BLOWING AND DRIFTING SNOW CONTINUE INTO THE
EVENING.
DECIDED TO KEEP THE WIND CHILL HEADLINES AS THEY ARE FOR NOW.
FOR TONIGHT...THE ARCTIC HIGH WILL BUILD INTO NEW ENGLAND OVERNIGHT.
TEMPERATURES WILL PLUMMET THROUGH THE EVENING, WITH LOWS -15F TO -25F
ACROSS THE NORTHERN HALF OF OUR FORECAST AREA. DOWNEAST AREAS WILL
EVEN DROP BELOW ZERO, WITH LOWS OF -5F TO -15F. WINDS WILL
GRADUALLY ABATE LATER TONIGHT IN RESPONSE TO THE WEAKENING
PRESSURE GRADIENT UNDER THE RIDGE, ESPECIALLY OVER FAR WESTERN
LOCATIONS. THEREFORE, IN SPITE OF THE VERY COLD AIR TEMPERATURES,
THE WIND CHILL ADVISORY STILL LOOKS APPLICABLE, AS OPPOSED TO A
WIND CHILL WARNING.
&&
.SHORT TERM /TUESDAY THROUGH WEDNESDAY/...
THE CORE OF BITTERLY COLD ARCTIC AIR WILL BE MOVG E OF THE FA TUE
MORN. AFT A VERY COLD START TO THE DAY...HI TEMPS SHOULD RECOVER
INTO THE SINGLE DIGITS BY MID TO LATE AFTN...WITH DOWNEAST AREAS
RECOVERING INTO THE TEENS BY ERLY EVE AS SFC WINDS BECOME SRLY
COMPONENT BEHIND DEPARTING SFC HI PRES MOVG E TOWARD THE OPEN
ATLC. THIS RETURN FLOW WILL BRING INCREASING CLDNSS FROM S TO N
ACROSS THE REGION TUE NGT...WITH LGT SN POSSIBLE TO PTNS OF THE FA
LATE TUE NGT.
MODELS THEN SHOW A S/WV COMPLEX MOVG E FROM CNTRL CAN AND THE
GREAT LKS TUE NGT INTO WED. THE SFC LOW WITH THIS SYSTEM IS XPCTD
TO REFORM FROM QB TUE NGT TO A SECONDARY LOW OVR THE S GULF OF ME
SW OF NOVA SCOTIA. THE SECONDARY LOW THEN GAINS MOMENTUM WED
AFTN...ABSORBING THE OLD PRIMARY LOW FROM QB BY WED EVE. A POCKET
OF SRLY LOW TO MID LVL WARM/MOISTURE ADVCN BEGINS TO DEVELOP OVR
ERN ME BEGINNING ERLY WED MORN JUST AHEAD OF THE DEVELOPING
SECONDARY...RESULTING IN MORE ORGANIZED SNFL CLIPPING ERN ME
MON MORN INTO ERLY AFTN BEFORE MOVING ENE INTO NB BY LATE WED
AFTN. MODELS VARY WITH REGARD TO THE QPF THAT MAY OCCUR OVR ERN
ME WITH THE TMG OF THIS EVENT...WITH THE 00Z DTMNSTC CANGEM AND
NAM MOST AGGRESSIVE AND THE GFS AND SPCLY ECMWF THE LEAST. WPC IS
LEANING MORE WITH THE GFS AND ECMWF MODELS ATTM...SO WE WEIGHT
THESE MODELS MORE WITH FCST 6HRLY QPF AND CORRESPONDING SNFL LATE
TUE NGT THRU WED. CONSIDERING THE UNCERTAINTY OF TMG OF
DEVELOPMENT OF THE SNFL SHIELD BEFORE THE SECONDARY MOVES AWAY
FROM THE REGION...WE KEPT SN TO LIQ RATIOS RELATIVELY CONSERVATIVE
AT 13.5 TO 1...WHICH RESULTS IN MAX TOTALS OF 3 TO 4 INCHES OVR SE
WASHINGTON COUNTY WHERE WE GO WITH CATEGORICAL POPS WITH LESSER
AMOUNTS AND POPS TO THE WNW.
SN SHOULD TAPER TO SN SHWRS FROM W TO E ACROSS THE REGION FROM
MID AFTN TO ERLY EVE...THEN END FROM S TO N OVRNGT WED...WITH
STRONGER LLVL COLD ADVCN XPCTD LATE WED NGT AND ERLY THU MORN WITH
A SECONDARY ARCTIC COLD FRONT.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/...
ANOTHER DEEP ARCTIC AIR MASS WILL FOLLOW THE SECONDARY COLD FRONT
ACROSS THE REGION FROM CNTRL CAN...WITH THIS AIR MASS NOT QUITE AS
COLD AS THE PRIOR AIR MASS AFFECTING THE FA ON TUE. UNDER FAIR
SKIES...HI TEMPS WILL BE WELL BLO SEASONAL AVGS FOR THE END OF FEB
THU AND FRI...WITH SOME RADIATIONAL COOLING POSSIBLE THU NGT AND
MSLY FRI NGT AS LARGE SPRAWLING SFC HI PRES RIDGES ENE INTO THE
REGION. WITH WEAK PRES GRAD FLOW INDICATED...THE BEST POTENTIAL
FOR COLDEST OVRNGT LOWS WILL BE ACROSS BROAD RVR VLYS OF NRN AND
CNTRL PTNS OF THE FA...WITH HILL TOP LCTNS LIKELY MAINTAINING A
LGT BREEZE KEEP OVRNGT LOWS NOT AS COLD. ANOTHER WV OF LOW PRES
TRACKING OFF THE SE U.S COAST WILL KEEP A LITTLE MORE PRES GRAD
AND PERHAPS HI CLD OVR THE DOWNEAST COAST BOTH NGTS LMTG THE
POTENTIAL OF VERY COLD LOW TEMPS.
SAT SHOULD CONT FAIR...BUT NOT AS COLD AS FCST AFTN 925 MB TEMPS
RISE FROM THE LOWER TO MID -20S TO -10S DEG C. WITH THE CNTR OF
STRONG SFC HI PRES TRACKING WELL S OF THE FA AS IT MOVES OFF THE
MID ATLC COAST...WINDS WILL LIKELY NOT HAVE MUCH CHC TO DECOUPLE
EVEN OVR VLY AREAS SAT NGT. SUN WILL BEGIN FAIR...THEN HI/MID
CLDNSS INCREASE LATER IN THE DAY AS A LARGE SHIELD OF LGT OVRRNG
SNFL APCHS FROM THE GREAT LKS AND QB PROV BY SUN EVE.
&&
.AVIATION /17Z MONDAY THROUGH FRIDAY/...
NEAR TERM: MVFR CONDITIONS WITH OCCASIONAL IFR IN LIGHT SNOW AT
KHUL/KBHB WILL LINGER THROUGH 14Z OR SO TODAY. THEN CONDITIONS
WILL GRADUALLY IMPROVE AS A COLD FRONT CROSSES THE AREA AND ALLOWS
COLDER AND DRIER AIR TO SPREAD OVER THE REGION. WEST WINDS WILL
INCREASE TO 10-15KT WITH GUSTS TO 25KT POSSIBLE. THIS MAY RESULT
IN BLOWING SNOW WHICH COULD REDUCE VISIBILITY TO IFR AT TIMES
THROUGH THIS EVENING. OTHERWISE, PREVAILING VFR CONDITIONS ARE
EXPECTED FROM 15Z SOUTH/21Z NORTH WITH CLEARING SKIES.
SHORT TO LONG TERM: VFR XPCTD ALL TAF SITES TUE THRU TUE
EVE...WITH MVFR CLGS POSSIBLE LATE TUE NGT AND THEN MVFR OR IFR
VSBYS WITH LGT SNFL DURING THE DAY WED. AFTWRDS...MVFR CLGS CONT
ACROSS NRN TAF SITES WED NGT INTO THU MORN WHILE DOWNEAST SITES
BECOME VFR. ALL SITES THEN BECOME VFR THU AFTN AND CONT SO THRU
FRI.
&&
.MARINE...
NEAR TERM: A GALE WARNING REMAINS IN PLACE FOR TODAY AND TONIGHT.
A COLD FRONT WILL CROSS THE WATERS THIS MORNING, FOLLOWED BY WEST
TO NORTHWEST WINDS OF 20 TO 30 KT WITH GUSTS IN EXCESS OF 35 KT.
BITTERLY COLD TEMPERATURES AND THE STRONG WINDS WILL COMBINE TO
CREATE HEAVY FREEZING SPRAY, ESPECIALLY OVER THE OUTER WATERS, SO
THE FREEZING SPRAY WARNING REMAINS IN PLACE FOR LATER TODAY
THROUGH TONIGHT.
SHORT TO LONG TERM: SCA OR LESS CONDITIONS XPCTD THRU THIS PTN OF
THE FCST. HVY FZGSPY SHOULD BECOME MDT BY 12Z TUE...BECOMING LGT
BY LATE DAY AND THEN ENDING BY WED MORN AS COLD ADVCN DIMINISHES
OVR THE WATERS AND EVENTUALLY REVERSES TO WARM ADVCN. WENT ABV WW3
GUIDANCE FOR FCST WV HTS BY A FACTOR OF 1.15 OR SO...BASED ON BIAS
TRENDS OBSVD OVR THE PAST FEW WEEKS.
&&
.CAR WATCHES/WARNINGS/ADVISORIES...
ME...WIND CHILL ADVISORY UNTIL 10 AM EST TUESDAY FOR MEZ001>006-010-
011-031-032.
WIND CHILL ADVISORY FROM 7 PM THIS EVENING TO 7 AM EST TUESDAY
FOR MEZ015>017-029-030.
MARINE...HEAVY FREEZING SPRAY WARNING UNTIL 7 AM EST TUESDAY FOR
ANZ050>052.
GALE WARNING UNTIL 4 AM EST TUESDAY FOR ANZ050>052.
&&
$$
NEAR TERM...HEWITT
AREA FORECAST DISCUSSION
NWS GRAND RAPIDS MI
302 PM EST MON FEB 23 2015
LATEST UPDATE...
SYNOPSIS/SHORT TERM/LONG TERM/HYDRO
.SYNOPSIS...
ISSUED AT 239 PM EST MON FEB 23 2015
A FAST MOVING LOW PRESSURE SYSTEM WILL TRACK EASTWARD THROUGH
ONTARIO TONIGHT AND TUESDAY. THIS SYSTEM WILL PROVIDE THE GREAT
LAKES REGION WITH WINDY CONDITIONS AND SOME SNOW. CONSIDERABLE
DRIFTING SNOW WILL BE POSSIBLE ON TUESDAY. ANOTHER ARCTIC AIRMASS
WILL TRACK IN BEHIND THIS DEPARTING STORM AND PERSIST INTO THE WEEKEND.
&&
.SHORT TERM...(THIS EVENING THROUGH WEDNESDAY NIGHT)
ISSUED AT 239 PM EST MON FEB 23 2015
THE MAIN ISSUE DEALS WITH THE IMPACT OF THE LOW PRESSURE SYSTEM
THAT TRACKS THROUGH ONTARIO TONIGHT AND TUESDAY. OVERALL IT LOOKS
LIKE ENOUGH IMPACTS TO WARRANT HEADLINES FOR THE ENTIRE REGION.
I DID CHECK IN WITH A COUPLE OF ROAD COMMISSIONS AND THEY
INDICATED THAT WINDS OVER 30 MPH WILL LEAD TO CONSIDERABLE
DRIFTING OF THE SNOW...ESPECIALLY IN RURAL AREAS. EVEN SOME
HIGHWAYS COULD BE IMPACTED. THE RUC MODEL SHOWS GUSTS TOPPING 40
KNOTS FROM NEAR GRAND RAPIDS NORTHEAST THROUGH MOUNT PLEASANT AND
BETTER THAN 35 KNOTS ELSEWHERE. THERE IS A SECONDARY MAX ALONG THE
LAKESHORE NORTH OF MUSKEGON...WITH BETTER THAN 40 KNOTS POSSIBLE.
I AM NOT CERTAIN WILL SEE SUCH HIGH WINDS. HOWEVER ENOUGH RISK
THERE TO GO WITH A HEADLINE. THE MAIN WINDOW OF STRONG WINDS
RANGES FROM 09Z TO 18Z FOR LUDINGTON...13Z TO 21Z FOR GRAND RAPIDS
AND 16Z TO 23Z FOR JACKSON.
SNOW ON TUESDAY WILL BE A SECONDARY CONCERN FOR THIS SYSTEM WITH AMOUNTS
EXPECTED TO RANGE FROM 2 TO 4 INCHES OF LAKE ENHANCED SNOW UP
NORTH FROM LUDINGTON TO HARRISON. FURTHER SOUTH GRAND RAPIDS AND
MOUNT PLEASANT ROUGHLY 1 TO 3 INCHES...TO AN INCH OR LESS FOR
JACKSON AND LANSING. STILL...WITH GUSTY WINDS AND
SNOW...VISIBILITIES COULD BE REDUCED CONSIDERABLY AT TIMES.
LOCATIONS SOUTHEAST OF GRAND RAPIDS COULD START THE DAY OFF WITH
SOME SUN.
WIND CHILL VALUES ON TUESDAY COULD START OFF AROUND -15
DEGREES...WHICH IS HAZARDOUS.
TUESDAY NIGHT AFTER A LULL IN THE WIND...WE COULD SEE A RETURN OF
SNOW AND POSSIBLE IMPACTS...MAINLY AFTER MIDNIGHT. WILL NEED TO
ASSESS THIS POSSIBILITY WITH LATER FORECASTS.
.LONG TERM...(THURSDAY THROUGH MONDAY)
ISSUED AT 239 PM EST MON FEB 23 2015
THE FOCUS OF THE LONG TERM IS THE EVOLUTION OF A SOUTHERN STREAM
SYSTEM THAT BOTH THE GFS AND ECMWF HAVE LATCHED ONTO FOR A COUPLE OF
DAYS NOW. CONDITIONS LOOK PRETTY DRY...BUT COLD FROM THURSDAY
THROUGH SATURDAY...AND LIKELY MONDAY TOO. HOWEVER IT`S THE PERIOD
FROM SATURDAY NIGHT THROUGH SUNDAY NIGHT THAT PROMISES TO BE
INTERESTING.
IT/S LOOKING INCREASINGLY LIKELY THAT PCPN WILL DEVELOP OVER THE SW
CWA SATURDAY EVENING...LIKELY AS SNOW...AND CONTINUE THROUGH SUNDAY.
THE GULF IS WIDE OPEN DUE TO HIGH PRESSURE NEAR THE EAST COAST AND
SO THERE WILL BE A STRONG INFLUX OF MOISTURE. DESPITE THE MOISTURE
CONTENT OF THIS SYSTEM...IT STILL HAS SOME ISSUES. ECMWF AND GFS
BOTH SHOW THIS BEGINNING AS AN INVERTED TROUGH AND THEN PHASING WITH
A NORTHERN STREAM CLIPPER AS IT PUSHES A COLD FRONT THROUGH THE CWA.
THIS ISN/T THE CLASSIC STRENGTHENING CLOSED LOW THAT MOVES FROM THE
SOUTHERN PLAINS NEWD. AT LEAST NOT YET. QPF WITH THE SYSTEM IS PROGD
IN THE 2/3 TO 3/4 INCH RANGE...WHICH IF ALL SNOW WOULD CERTAINLY BE
PLOWABLE. THE WARMER ECMWF WOULD LIKELY TURN PCPN TO MIXED RAIN AND
SNOW ACROSS THE SOUTHERN CWA. FOR CONTINUITY SAKE WE KEPT THE PCPN
AS SNOW IN THE GRIDS FOR NOW.
ALL OF THE PCPN WILL LIKELY END MONDAY AS THE SYSTEM MOVES EAST AND
ANOTHER SHOT OF COLD AIR MOVES SOUTH.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON)
ISSUED AT 1240 PM EST MON FEB 23 2015
LAKE EFFECT SNOW SHOWERS WILL DIMINISH THIS AFTERNOON AT MKG AND
MAY INCREASE A BIT AT GRR AS THE BAND PUSHES INLAND. IT`S POSSIBLE
THAT WE COULD SEE A MVFR CIG AT GRR THIS AFTERNOON.
OTHERWISE...WINDS WILL INCREASE FROM THE SOUTHWEST AFTER MIDNIGHT
AS ANOTHER SYSTEM APPROACHES. SNOW WILL DEVELOP TUESDAY MORNING AT
MKG BUT MAY TAKE UNTIL THE AFTERNOON TO DEVELOP AT THE OTHER TAF SITES.
&&
.HYDROLOGY...
ISSUED AT 239 PM EST MON FEB 23 2015
WITH NO MAJOR WARM UPS OR RAINFALL HEADED OUR WAY IN THE NEAR
FUTURE...RUNOFF WILL BE LIMITED. SERIOUS ICE JAMS AND FLOODING
CONCERNS ARE UNLIKELY UNTIL A SIGNIFICANT WARM UP AND RAINFALL
OCCUR. CONSIDERABLE ICE DOES EXIST IN THE RIVERS SO WE WILL NEED
TO MONITOR TRENDS CLOSELY. FOR NOW WITH CONDITIONS STABLE DUE TO
THE ARCTIC AIRMASS IN PLACE...THE RISK IS SOMEWHAT LIMITED FOR
FLOODING.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...WINTER WEATHER ADVISORY FROM 4 AM TO 7 PM EST TUESDAY FOR
MIZ037>040-043>046-050>052-056>059-064>067-071>074.
LM...NONE.
&&
$$
SYNOPSIS...MJS
SHORT TERM...MJS
LONG TERM...04
AVIATION...04
HYDROLOGY...MJS
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
1217 PM EST MON FEB 23 2015
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 532 AM EST MON FEB 23 2015
WV IMAGERY AND RUC ANALYSIS INDICATED A PROMINENT RIDGE FROM THE ERN
PACIFIC INTO BC AND MID LEVEL LOW NEAR JAMES BAY RESULTING IN NNW
FLOW FROM NRN CANADA INTO THE WRN GREAT LAKES. A VIGOROUS UPSTREAM
SHORTWAVE TROUGH WAS LOCATED OVER NRN CANADA. AT THE SFC...LIGHT
WRLY FLOW PREVAILED ACROSS THE REGION AS ARCTIC HIGH PRES SLOWLY
BUILDS TO THE SE TO WRN IA. WITH THE EXTENSIVE ICE COVER ACROSS LAKE
SUPERIOR...RADAR/SATELLITE INDICATED ONLY MINIMAL/WEAK LES TO NEAR
MUNISING AND GRAND MARAIS THAT WAS SLOWLY LIFTING OFFSHORE AS WINDS
BACK. EARLY MORNING TEMPS GENERALLY RANGING BETWEEN -10F TO -20F
ALONG WITH WINDS AROUND 5 MPH PRODUCED WIND CHILLS IN THE -20 TO -35
RANGE.
TODAY...WIND CHILL VALUES WILL ONLY SLOWLY MODERATE THIS MORNING AS
TEMPS CLIMBING BACK TOWARD ZERO WILL BE OFFSET BY INCREASING SW
WINDS TO AROUND 10 MPH. OTHERWISE...QUIET WEATHER IS EXPECTED WITH
GRADUALLY INCREASING MID AND HIGH CLOUDS IN THE WAA PATTERN BETWEEN
THE RETREATING HIGH AND THE CLIPPER LOW MOVING SSE FROM CANADA. THE
TIGHTENING PRES GRADIENT WILL BRING GUSTY WINDS BY LATE TODAY MAKING
IT STILL FEEL VERY COLD EVEN AS TEMPS CLIMB TO HIGHS NEAR 10F.
TONIGHT...THE NRN CANADA SHRTWV WILL QUICKLY DIVE TO THE SSE TO THE
NORTH SHORE OF LAKE SUPERIOR BY 12Z/TUE. THE WAA AND PATTERN AND
280K ISENTROPIC LIFT AHEAD OF THE TROUGH WILL BRING WIDESREAD LIGHT
SNOW TO THE REGION. EXPECT A DELAY TO THE ONSET OF SNOW TIL LATE
EVENING AND OVERNIGHT GIVEN THE VERY DRY AIRMASS IN PLACE OVER THE
REGION AND THE TIME TO SATURATE THE 925-700 MB LAYER...PER FCST
SOUNDINGS. POTENTIAL SNOWFALL AMOUNTS OF A HALF INCH TO AROUND 2
INCHES ARE CONSISTENT WITH 1.0-1.5 G/KG AVAILABLE DURING THE PERIOD
OF STRONGER LIFT AND QPF BETWEEN 0.03-0.08 WITH SLR VALUES AROUND
20/1. THE GREATEST AMOUNTS ARE EXPECTED FROM THE KEWEENAW INTO THE
ERN CWA WHERE THE FCST LIFT AND A LONGER PERIOD OF SATURATION IS
FCST. POTENTIAL FOR LAKE ENHANCEMENT WITH SW FLOW OFF OF SOME
REMAINING OPEN WATER IN NRN LAKE MI SHOULD REMAIN MAINLY EAST OF THE
CWA...PER HIGHER RES MODELS 230-250 FCST LOW LEVEL FLOW DIRECTION.
.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 250 AM EST MON FEB 23 2015
TUESDAY THROUGH SUNDAY WILL BE MARKED BY BOOKEND LOW PRESSURE
SYSTEMS...WITH HIGH PRESSURE IN BETWEEN. THE FIRST AT 12Z TUESDAY
WILL BE SET UP FROM S HUDSON BAY THROUGH CENTRAL ONTARIO...AND
CENTRAL LAKE SUPERIOR...DRAGGING A COLD FRONT ACROSS THE W THIRD OF
THE CWA. THE FRONTAL BOUNDARY WILL SWIFTLY EXIT E...AND RESIDE FROM
JAMES BAY THRUOGH FAR SE LAKE SUPERIOR BY 18Z TUESDAY. 1-2 IN OF NEW
SNOW WILL BE POSSIBLE TUESDAY OVER MUCH OF THE CWA...WITH THE
HIGHEST VALUES FAR N AND E. WHILE WINDS ALOFT WILL BE DIMINISHING
FROM THE 40-50KT WINDS OVERNIGHT...SFC WINDS WILL BE STEADY TO ON
THE INCREASE. LOOK FOR WINDS OF 10-20KTS DURING THE DAY
TUESDAY...HIGHEST W AND ALONG LAKE SUPERIOR.
WILL BE INTERESTING TO SEE WHAT THE INCREASED SW WINDS TODAY-
TONIGHT...AND NW WINDS TUESDAY DO TO THE RELATIVLY THIN AND
FRACTURED ICE COVERING MUCH OF LAKE SUPERIOR. HOW IT PROGRESSES WILL
HAVE A LARGE IMPACT ON THE AREAL COVERAGE AND INTENSITY OF LAKE
EFFECT SNOW BANDS TUESDAY AFTERNOON THROUGH THURSDAY ON MAINLY NW TO
WNW WINDS.
SLOWLY FALLING INVERSION HEIGHTS TUESDAY NIGHT...AND THE DGZ GOING
AWAY AS MUCH COLDER AIR SLIDES IN ON THE NW WINDS WILL RESULT IN THE
RETURN OF SMALL SNOWFLAKES THAT WILL NOT ACCUMULATE TO MUCH BUT ARE
VERY AFFECTIVE AT REDUCING VIS. ANOTHER COLD ARCTIC ARIMASS WILL BE
ABLE TO SLIDE INTO THE REGION AS HIGH PRESSURE OVER MUCH OF THE W
HALF OF CANADA SLOWLY SINKS ACROSS S CENTRAL CANADA...THE N AND
CENTRAL PLAINS...AND THE UPPER GREAT LAKES BY THE END OF THE WORK
WEEK. LIGHT LES ON N TO WNW WINDS WILL BE THE RULE.
WIND CHILL VALUES WILL AGAIN FALL INTO THE -20 TO -30F RANGE LATE
TUESDAY NIGHT THROUGH WEDNESDAY MORNING. THAT 10MPH WIND PORTION OF
THE WIND CHILL ADVISORY SHOULD BE MET ACROSS MOST OF THE CWA...WITH
STRONGER NW WINDS NEARING 15MPH N CENTRAL AND E ALONG LAKE SUPERIOR.
THE APPARENT TEMPERATURE PORTION OF WIND CHILL ADVISORY CRITERIA IS
-25 TO -34F.
LATE WEDNESDAY NIGHT INTO EARLY THURSDAY MORNING MAY AGAIN BRING US
DOWN TO 20 TO NEAR 30 BELOW ZERO WIND CHILLS. HOWEVER...THE NW WINDS
SHOULD BE MUCH LIGHTER.
THURSDAY NIGHT-FRIDAY WILL BE A PERIOD OF MAINLY W TO WSW WINDS.
LAKE EFFECT SNOW SHOWERS SHOULD BE EITHER MIMIMAL OR NON-
EXISTANT...AND IMPACTING THE KEWEENAW PENINSULA AND RIGHT ALONG THE
LAKE SUPERIOR SHORELINE AROUND AND E OF GRAND MARAIS.
EXPECT DRY WEATHER SATURDAY...BUT INCREASING SW WINDS AND INVADING
CLOUDS FROM THE W. 850MB TEMPS WILL RISE TO AROUND -11 TO -13C
SATURDAY AND SUNDAY. SFC TEMPERATURES SHOULD REBOUND TO NEAR
20F...WHICH IS STILL AROUND 10 DEGREES BELOW NORMAL FOR THIS TIME OF
YEAR. SUNDAY SHOULD BE A COUPLE DEGREES WARMER...BUT FILLED WITH
MORE CLOUDS AND SNOW FOR THE ENTIRE CWA. EARLY INDICATIONS FROM THE
GFS POINT TO 2-5IN OF SNOW CWA WIDE LATE SATURDAY AFTERNOON THROUGH
SUNDAY EVENING. THE BEST MOISTURE LOOKS TO REMAIN TO OUR S AS UPPER
MI IS IN BETWEEN 2 LOWS /ONE OVER HUDSON BAY...AND ANOTHER EJECTING
OUT OF THE CENTRAL PLAINS/.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON)
ISSUED AT 1217 PM EST MON FEB 23 2015
VFR CONDITIONS WILL CONTINUE AT ALL 3 TAF SITES INTO THIS EVENING.
THE SW WINDS WILL STRENGTHEN AND TURN GUSTY AS THE PRESSURE GRADIENT
TIGHTENS AHEAD OF A COLD FRONT APPROACHING FROM THE NW. SNOW IN
ADVANCE OF THIS FRONT WILL ARRIVE FROM NW TO SE LATE THIS EVENING.
THE DRY NATURE OF THE ANTECEDENT AIRMASS WILL MAINTAIN VFR
CONDITIONS INITIALLY DESPITE THE THICKENING CLOUD COVER.
HOWEVER...CONDITIONS WILL DROP TO MVFR AFT 06Z AND LIKELY TO IFR AT
CMX AND IWD WHERE THE HEAVIER SNOW IS EXPECTED AND THE VISIBILITY
WILL BE LOW DUE TO BLOWING SNOW.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 532 AM EST MON FEB 23 2015
SOUTHWEST WINDS WILL QUICKLY INCREASE THIS AFTERNOON BETWEEN LOW
PRESSURE DROPPING SOUTHEAST THROUGH NORTHERN ONTARIO AND HIGH PRES
MOVING INTO THE OH VALLEY. THIS WILL LEAD TO SOUTHWESTERLY GALES OF
35-40KTS OVER PORTIONS OF LAKE SUPERIOR THIS AFTERNOON AND EVENING.
A GALE WARNING REMAINS IN EFFECT FOR MUCH OF WESTERN/CENTRAL LAKE
SUPERIOR FOR LATE THIS AFTERNOON AND TONIGHT. THEN AS A COLD FRONT
SLIDES SOUTHEAST ACROSS LAKE SUPERIOR LATE TONIGHT INTO TUESDAY
MORNING AND SHIFT WINDS TO THE NORTHWEST...THERE MAY BE A FEW GALE
FORCE GUSTS TO 35 KNOTS BEHIND THE FRONT ON TUESDAY OVER EASTERN
LAKE SUPERIOR. A HIGH PRESSURE RIDGE WILL BUILD BACK INTO THE AREA
WEDNESDAY AND REMAIN INTO FRIDAY...LEADING TO GENERALLY LIGHT WINDS
BELOW 20KTS.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
GALE WARNING FROM 7 PM THIS EVENING TO 7 AM EST TUESDAY FOR
LSZ266.
GALE WARNING FROM 4 PM EST /3 PM CST/ THIS AFTERNOON TO 7 AM EST
/6 AM CST/ TUESDAY FOR LSZ162-263-264.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...JLB
LONG TERM...KF
AVIATION...07
MARINE...JLB
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
244 PM CST MON FEB 23 2015
.SHORT TERM...(THIS EVENING THROUGH TUESDAY)
ISSUED AT 230 PM CST MON FEB 23 2015
A STRONG PRESSURE GRADIENT TONIGHT WILL KEEP TEMPS FROM FALLING
MUCH...AND WILL LIKELY HOLD AND BEGIN TO RISE OVERNIGHT. TEMPERATURES
ACROSS SOUTHERN MANITOBA ARE IN THE MID/UPPER 20S AHEAD OF A
STRONG WARM FRONT MOVING INTO THE DAKOTAS THIS AFTN. THESE WARMER
TEMPS WILL LIKELY ADVECT SE AND SPREAD ACROSS WESTERN MN DURING
THE EVENING...AND ACROSS SOUTHERN MN AFT MIDNIGHT. IN
ADDITION...STRONG WAA AHEAD OF THIS FRONT WILL LEAD TO SOME -SN
DURING THE EVENING...ESPECIALLY ACROSS CENTRAL AND NORTHERN MN.
HOWEVER...THE INITIAL DRY AIR MASS IN SOUTHERN MN WILL LIKELY
DISSIPATE ANY PRECIPITATION THAT FALLS UNTIL WELL AFT MIDNIGHT AS
ANOTHER STRONGER SHRTWV ACROSS CENTRAL MANITOBA RACING SE OVER
MN/WI BY MORNING. LATEST WV IMAGERY SHOWS THIS SHRTWV FAIRLY
STRONG...SO I WOULD NOT BE SURPRISE TO SEE SOME ACCUMULATING
SNOWFALL IN OUR NE CWA BY LATE TUESDAY MORNING. HOW FAR SW THIS
AREA OF LIGHT SNOW OCCURS IS DEPENDENT ON THE DEPTH OF THE
MOISTURE AND LOCATION OF THE SHRTWV. BY LATE MORNING...A COLD
FRONT WOULD HAVE MOVED ACROSS MOST OF MN...CAUSING TEMPS DURING
THE AFTN TO SLOWLY FALL. GUSTY WINDS WILL ALSO CONTINUE THRU THE
AFTN AS STRONG CAA DEVELOPS.
.LONG TERM...(TUESDAY NIGHT THROUGH MONDAY)
ISSUED AT 230 PM CST MON FEB 23 2015
NO SIGNIFICANT CHANGES TO THE EXTENDED FORECAST. AS ALLUDED TO IN THE
PREVIOUS DISCUSSION...COLD WEATHER IS A CERTAINTY...WITH LINGERING
LIGHT SNOW REMAINING POSSIBLE...BUT NOT LIKELY ACROSS CENTRAL MN AND
WESTERN WI.
THERE ARE TWO MAIN CHANCES FOR PRECIPITATION. THE FIRST COMES
WEDNESDAY AS A POTENT PV ANOMALY DIVES ALONG THE MISSOURI RIVER
VALLEY AND WILL PRODUCE A QUICK BURST OF MODERATE TO HEAVY SNOWFALL.
THE BULLSEYE OF QPF MATCHES UP WILL WITH THE H850 THETA_E
ADVECTION...BUT THIS FORCING REMAINS SOUTHWEST OF THE CWA. SO...LIGHT
SNOW SHOULD REMAIN CONFINED SOUTH AND WEST OF THE UPPER MINNESOTA
RIVER VALLEY.
THIS SYSTEM WILL BE FOLLOWED BY ANOTHER ARCTIC HIGH WITH COLD
TEMPERATURES AND CLEAR SKIES. THIS HIGH WILL SHIFT EASTWARD AS AN
UPPER LEVEL TROUGH CARVES OUT ACROSS THE 4-CORNERS REGION...WITH
DOWNSTREAM SOUTHWEST FLOW DEVELOPING ACROSS THE CENTRAL CONUS. THE
NORTHERN EXTEND OF THIS SOUTHWEST FLOW WILL DETERMINE THE STORM
TRACK...AND POTENTIAL FOR SNOW OVER THE WEEKEND. AT THIS TIME...DID
NOT STRAY FROM A BLENDED GUIDANCE...WHICH HAS THE HEAVIEST SNOW
CLOSER TO THE I-80 CORRIDOR THAN THE I-90 CORRIDOR.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON)
ISSUED AT 1125 AM CST MON FEB 23 2015
GUSTY SW WINDS WILL BE THE MAIN CONCERN THRU 00Z AS THE PRESSURE
GRADIENT STRENGTHENS. OTHERWISE...VFR CONDS WITH -SN POSSIBLE IN
KAXN AFT 01Z BASED ON THE LATEST HRRR REFLECTIVITY RUN.
ELSEWHERE...THE MAIN CHC OF -SN WILL HOLD OFF UNTIL AFT 06Z...WITH
THE BEST TIME FRAME BETWEEN 9-15Z WHERE BOTH VSBY/CIGS DROP INTO
THE MVFR RANGE. A PERIOD OF IFR VSBY IN -SN IS POSSIBLE IN EC
MN/WC WI IF THE WX SYSTEM MOVING INTO FAR NW MN STRENGTHENS A BIT
MORE. WILL CONTINUE TO MONITOR UPSTREAM OBS IN NW MN AND SEE IF
AMD ARE NEEDED THIS AFTN. WINDS WILL REMAIN GUSTY THRU THE
NIGHT/MORNING HRS...WITH A SHIFT TO THE WEST/NW BY MORNING.
KMSP...
MAIN CONCERN IS THE CROSSWIND COMPONENT THIS AFTN WITH WINDS
POSSIBLY GUSTING OVER 25 KTS AT TIMES /230-210 DEGREES/. 30 KT
GUSTS ARE NOT EXPECTED...BUT WILL MONITOR IF CONDS CHG.
OTHERWISE...CIGS WILL LOWER TONIGHT TO LOW END VFR WITH A CHC OF
-SN AFT 9Z. MVFR VSBY IN -SN IS POSSIBLE BETWEEN 9-15Z. CONFIDENCE
REMAINS LOW ON VSBYS LOWER THAN 3SM IN -SN. WINDS WILL REMAIN
GUSTY OVERNIGHT...AND BACK TO THE WEST AFT 9Z...AND TO THE NW BY
12-15Z AS THE COLD FRONT MOVES THRU.
/OUTLOOK FOR KMSP/
WED...VFR. WINDS NNW 10 KTS.
THU...VFR. WINDS NW 5-10 KTS.
FRI...VFR. WINDS WSW 5 KTS.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
&&
$$
SHORT TERM...JLT
LONG TERM...JRB
AVIATION...JLT
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
1128 AM CST MON FEB 23 2015
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 412 AM CST MON FEB 23 2015
THE PRIMARY CONCERN IN THE SHORT TERM WILL BE WIND CHILLS EARLY THIS
MORNING...AND THEN ATTENTION SHIFTS TO THE CHANCE FOR LIGHT SNOW
LATE TONIGHT.
CLEAR SKIES AND SURFACE HIGH PRESSURE HAVE CONTRIBUTED TO QUITE A
COLD NIGHT ACROSS THE AREA...WITH WIDESPREAD TEMPERATURES RANGING
FROM 10 BELOW TO 20 BELOW ACROSS THE FORECAST AREA. THE COMBINATION
OF THESE FRIGID TEMPERATURES WITH A 5-7 MPH WIND HAS YIELDED WIND
CHILL READINGS FROM 25 BELOW TO 35 BELOW ACROSS THE MAJORITY OF THE
FORECAST AREA. THE ONE EXCEPTION IS ALONG THE MN RIVER
VALLEY...WHERE LIGHTER WINDS IN CLOSER PROXIMITY TO THE HIGH
PRESSURE RIDGE AXIS HAVE MADE FOR SLIGHTLY WARMER WIND CHILLS IN THE
15 TO 20 BELOW RANGE. WINDS ARE FORECAST TO INCREASE A COUPLE KNOTS
AROUND DAYBREAK HOWEVER...WHICH WOULD PUSH APPARENT TEMPERATURES TO
AROUND THE 25 BELOW MARK WHERE THEY ARE NOT CURRENTLY MEETING
ADVISORY CRITERIA. WILL THEREFORE KEEP THE CURRENT ADVISORY THAT
ENCOMPASSES THE ENTIRE CWA IN TACT THROUGH 10 AM CST.
THE AFOREMENTIONED INCREASE IN WINDS WILL ENSUE THROUGH THE MORNING
HOURS...WITH THE SOUTHWESTERLY DIRECTIONAL COMPONENT YIELDING A
MODERATION IN TEMPERATURES FOR WEST CENTRAL AND SOUTHWEST MN. HIGHS
THERE WILL CLIMB WELL INTO THE 20S...WHILE CENTRAL MN AND WEST
CENTRAL WI EXPERIENCE COOLER HIGHS IN THE 10 TO 20 DEGREE RANGE.
HIGH CLOUDS INCREASE THIS AFTERNOON AS A SHORTWAVE APPROACHES FROM
CANADA. DEEPER SATURATION AND WEAK LIFT ARRIVE BETWEEN 06Z AND 09Z
TUESDAY INTO CENTRAL MN/WI. HAVE INCLUDED 20-30 POPS GENERALLY ALONG
AND NORTH OF THE INTERSTATE 94 CORRIDOR...WHERE A COUPLE TENTHS TO A
HALF INCH NEW SNOW ON THE GROUND APPEARS POSSIBLE BY DAYBREAK
TUESDAY.
.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 412 AM CST MON FEB 23 2015
DURING THE EXTENDED...WE WILL CONTINUE TO ADD ON TO OUR TEMPERATURE
DEPARTURE FOR THE MONTH...WHICH SAW ANOTHER 9 TENTHS OF A DEGREE
ADDED ON TO THE DEPARTURE FROM NORMAL AFTER YESTERDAYS
AVERAGE TEMPERATURE DEPARTURE OF 27 DEGREES BELOW NORMAL. ON THE
MONTH...MSP NOW SITS AT 8.1 DEGREES BELOW NORMAL AND WILL LIKELY
FINISH CLOSE TO 10 DEGREES BELOW NORMAL AFTER WE GET 3 MORE DAYS
WEDNESDAY...THURSDAY...AND FRIDAY WHERE THE AVERAGE TEMPERATURE
DEPARTURE SHOULD BE NEAR OR GREATER THAN 20 DEGREES BELOW NORMAL.
THE REASON THE COLD LOOKS TO STAY...IS THE LARGE SCALE WEATHER
PATTERN DOES NOT LOOK TO CHANGE ALL THAT MUCH...WITH NOTHING MORE
THAN A WESTWARD SHIFT IN THE RIDGE/TROUGH/RIDGE PATTERN THAT HAS
BEEN IN PLACE PRETTY MUCH ALL OF FEBRUARY. WITHIN THIS
PATTERN...WE WILL BE SCRAPPED BY A STRONG CLIPPER GOING INTO THE
WRN GREAT LAKES TUESDAY AND ANOTHER DIVING SOUTH ACROSS THE
DAKOTAS ON WEDNESDAY. THE BEST SHOT AT SEEING ANY MEANINGFUL SNOW
LOOKS TO COME THIS WEEKEND AS SOUTHERN STREAM ENERGY GETS PULLED
INTO THE NORTHERN STREAM.
A FEW MINOR CHANGES WERE NEEDED TO THE FORECAST TUESDAY AND
WEDNESDAY. HIGHS WERE KNOCKED BACK A COUPLE OF DEGREES ON TUESDAY AS
WE WILL BE FIRMLY WITHIN STRONG CAA IN THE WAKE OF THE COLD FRONT
COMING THROUGH TONIGHT. THIS WILL LEAD TO GRADUALLY FALLING
TEMPERATURES DURING THE AFTERNOON ON TUESDAY AS NW WINDS LIKELY GUST
TO BETWEEN 30 AND 40 MPH. ALSO REMOVED THE POPS ACROSS SW MN ON
TUESDAY AS THEY WILL BE UNDER THE INFLUENCE OF SUBSIDENCE WITHIN THE
RIGHT EXIT REGION OF A NORTHWESTERLY JET STREAK. RAISED THE CHANCE
POPS A BIT TUESDAY MORNING IN THE EAST WHERE THE SNOW ARRIVING THERE
TONIGHT WILL BE EXITING DURING THE MORNING. LIKE MOST OF THE SYSTEMS
WE HAVE SEEN IN THIS PATTERN...THIS WILL ONLY RESULT IN AROUND A
HALF INCH OF SNOW IN WRN WI. FOR WEDNESDAY...MODELS CONTINUE TO
PAINT A SWATH OF 2-4 INCHES OF SNOW GOING FROM WESTERN NODAK TOWARD
WESTERN IOWA. THE BRUNT OF THIS WAVE STILL LOOKS TO REMAIN SW OF THE
MPX AREA...THOUGH THE ECMWF/SREF/NAM ALL SHOW THE NE EDGE OF THE
SNOW BAND COMING ABOUT AS FAR NE AS THE UPPER MN RIVER VALLEY...SO
ADDED SOME CHANCE POPS SW OF THE MN RIVER TO ACCOUNT FOR THAT. STILL
NOT CONVINCED WE WILL SEE SNOW IN THE MPX CWA WITH THIS SYSTEM AS
NORTHERLY LOW LEVELS WINDS WILL RESULT IN DRY AIR UNDERCUTTING THIS
PRECIP SHIELD...WHICH IS THE SCENARIO THE 23.00 AND 23.06 GFS SHOWS
PLAYING OUT.
BESIDE THE LIGHT SNOW IN THE SW...THIS HIGH WILL BRING US ANOTHER
STINT IN ARCTIC AIR TUESDAY NIGHT THROUGH THURSDAY NIGHT.
HOWEVER...IT WILL NOT BE QUITE AS COLD AS WHAT WE JUST EXPERIENCED
SUNDAY...AS H85 TEMPS WILL BE ABOUT 5C WARMER THAN THEY WERE OVER
THE WEEKEND. STILL...HIGHS ON THURSDAY WILL BE MOSTLY IN THE SINGLE
DIGITS...WITH DOUBLE DIGIT BELOW ZERO LOWS LIKELY THURSDAY AND
FRIDAY MORNINGS ACROSS CENTRAL MN INTO WISCONSIN. OF COURSE THIS COLD
MEANS WE WILL HAVE TO BE ON THE LOOKOUT FOR MORE WIND CHILL ISSUES
AND WEDNESDAY NIGHT INTO THURSDAY MORNING IS STILL LOOKING TO BRING
US ANOTHER ROUND OF WIND CHILL ADVISORY WORTHY APPARENT TEMPERATURES
ACROSS CENTRAL MN.
FOR THE WEEKEND...THE ECMWF AND GFS CONTINUE TO SHOW A PLOWABLE
SNOWFALL HITTING THE SE THIRD OR SO OF THE MPX CWA. THE MAIN
DIFFERENCE BETWEEN THE ECMWF AND GFS IS ONE OF TIMING...WITH THE
ECMWF BEING ABOUT 12 HOURS BEHIND THE GFS. OTHERWISE...THEY BOTH
SHOW A DEEP TROUGH/NEARLY CLOSED UPPER LOW DEVELOPING OVER THE 4
CORNERS REGION BY SATURDAY...WITH A PIECE OF THIS ENERGY GETTING
PULLED NE INTO THE GREAT LAKES BY EARLY NEXT WEEK BY A POSITIVELY
TILTED NORTHERN STREAM TROUGH WORKING ACROSS SRN CANADA. HAVE
INCREASED POPS INTO THE 40S FOR THE SE CWA SATURDAY NIGHT AND
SUNDAY. ALTHOUGH IT IS LOOKING INCREASINGLY LIKELY THAT WE WILL
START MARCH WITH SHOVEL WORTHY SNOW...MODELS TRADITIONALLY STRUGGLE
WITH PHASING SYSTEMS SUCH AS THIS MORE THAN 3 OR 4 DAYS OUT...SO I
WOULD NOT GET YOUR HOPES UP TOO MUCH FOR SEEING MEASURABLE UNTIL THE
FORECAST LOOKS LIKE THIS TUESDAY OR WEDNESDAY AND BEYOND.
ON THE SNOW NOTE...THE REST OF FEBRUARY LOOKS TO GO OFF MOSTLY SNOW
FREE...BRINGING TO AN END ONE OF THE LEAST SNOWIEST METEOROLOGICAL
WINTERS WE HAVE SEEN IN TWO DECADES. FOR DEC/JAN/FEB...THE 15.6" OF
SNOW SO FAR AT MSP AND THE 16.6" AT EAU ARE THE LEAST BOTH LOCATIONS
HAVE SEEN SINCE THE WINTER OF 1994-95...WHILE THE PALTRY 9" OBSERVED
SO FAR THIS METEOROLOGICAL WINTER AT STC IS THE LEAST SINCE 1986-87.
OF COURSE WINTER IN MINNESOTA AND WISCONSIN DOES NOT END WITH
FEBRUARY...BUT IT WILL TAKE QUITE THE SPRING RALLY FOR US TO GET OUR
SEASONAL SNOWFALL TOTALS UP ANYWHERE NEAR OUR NORMAL OF 50 TO 55
INCHES.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON)
ISSUED AT 1125 AM CST MON FEB 23 2015
GUSTY SW WINDS WILL BE THE MAIN CONCERN THRU 00Z AS THE PRESSURE
GRADIENT STRENGTHENS. OTHERWISE...VFR CONDS WITH -SN POSSIBLE IN
KAXN AFT 01Z BASED ON THE LATEST HRRR REFLECTIVITY RUN.
ELSEWHERE...THE MAIN CHC OF -SN WILL HOLD OFF UNTIL AFT 06Z...WITH
THE BEST TIME FRAME BETWEEN 9-15Z WHERE BOTH VSBY/CIGS DROP INTO
THE MVFR RANGE. A PERIOD OF IFR VSBY IN -SN IS POSSIBLE IN EC
MN/WC WI IF THE WX SYSTEM MOVING INTO FAR NW MN STRENGTHENS A BIT
MORE. WILL CONTINUE TO MONITOR UPSTREAM OBS IN NW MN AND SEE IF
AMD ARE NEEDED THIS AFTN. WINDS WILL REMAIN GUSTY THRU THE
NIGHT/MORNING HRS...WITH A SHIFT TO THE WEST/NW BY MORNING.
KMSP...
MAIN CONCERN IS THE CROSSWIND COMPONENT THIS AFTN WITH WINDS
POSSIBLY GUSTING OVER 25 KTS AT TIMES /230-210 DEGREES/. 30 KT
GUSTS ARE NOT EXPECTED...BUT WILL MONITOR IF CONDS CHG.
OTHERWISE...CIGS WILL LOWER TONIGHT TO LOW END VFR WITH A CHC OF
-SN AFT 9Z. MVFR VSBY IN -SN IS POSSIBLE BETWEEN 9-15Z. CONFIDENCE
REMAINS LOW ON VSBYS LOWER THAN 3SM IN -SN. WINDS WILL REMAIN
GUSTY OVERNIGHT...AND BACK TO THE WEST AFT 9Z...AND TO THE NW BY
12-15Z AS THE COLD FRONT MOVES THRU.
/OUTLOOK FOR KMSP/
WED...VFR. WINDS NNW 10 KTS.
THU...VFR. WINDS NW 5-10 KTS.
FRI...VFR. WINDS WSW 5 KTS.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
&&
$$
SHORT TERM...LS
LONG TERM...MPG
AVIATION...JLT
AREA FORECAST DISCUSSION
NWS RALEIGH NC
257 PM EST MON FEB 23 2015
.SYNOPSIS..A COLD FRONT WILL SETTLE SOUTHEAST OF THE AREA THIS
AFTERNOON. A WEAK WAVE OF LOW PRESSURE WILL TRACK NORTHEASTWARD
ALONG THE FRONT TONIGHT THROUGH TUESDAY... AS ARCTIC HIGH PRESSURE
BUILDS INTO THE AREA FROM THE NORTH. A SECOND STRONGER LOW PRESSURE
AREA WILL TRACK ALONG THE FRONT MIDWEEK... MOVING JUST SOUTHEAST OF
THE AREA WEDNESDAY NIGHT THROUGH THURSDAY.
&&
.NEAR TERM /THROUGH TUESDAY NIGHT/...
AS OF 1015 AM MONDAY...
A LOW AMPLITUDE SHORTWAVE AND ASSOCIATED WEAK SURFACE LOW ARE
DEPARTING THE SC COAST THIS MORNING. ANAFRONTAL PRECIP MAINLY
SOUTHEAST OF THE TRIANGLE AREA WILL ALSO CONTINUE TO EXIT TO THE
EAST THROUGH EARLY AFTERNOON. WEAK COLD ADVECTION WILL PERSIST THIS
AFTERNOON BEFORE THE STRONGER SURGE OCCURS THIS EVENING AHEAD THE
ARCTIC HIGH BUILDING ACROSS THE CENTRAL APPALACHIANS. DUE TO THE
DELAYED ARRIVAL OF COLDER LOW-LEVEL AIR...THE WETBULB FREEZING LINE
IS STILL WELL TO OUR NORTH IN CENTRAL VA AND BY THE TIME IT SINKS
SOUTH IN THE NORTHERN COASTAL PLAIN THIS AFTERNOON... ALL DEEPER
MOISTURE AND PRECIP WILL EITHER HAVE DEPARTED OR PRECIP WON`T BE OF
SUFFICIENT INTENSITY TO CAUSE WETBULBING OR ANY WINTRY IMPACTS.
LATEST GUIDANCE REFLECTS THIS. WILL KEEP THE GENERAL TREND OF POPS
GOING AND JUST MAKE SOME ALTERATIONS TO ACCOUNT FOR LATEST
RADAR....WITH POPS ENDING AFTER 18Z. WILL ALSO HAVE AN EYE ON THE
POTENTIAL FOR A MESOSCALE BAND OF SHALLOW MOISTURE AND PRECIP (MOST
LIKELY SLEET BASED ON TEMPS AROUND -10C IN THE SHALLOW SATURATED
LAYER) IN THE 21Z TO 03Z TIME FRAME...THOUGH NO IMPACT WOULD BE
EXPECTED AT THIS TIME. HI-RES MODELS ARE STILL SPLIT ON WHETHER OR
NOT THIS WILL DEVELOP...BUT MODELS HAVE BEEN SHOWING SOMETHING OF
THIS NATURE FOR MULTIPLE RUNS.
REGARDING TEMPS...THICKNESSES WILL STEADILY FALL THROUGHOUT THE DAY
IN THE NORTHEAST FLOW...SO FOR MANY LOCATIONS HIGHS IN THE UPPER 30S
NORTH TO MID 40S SOUTH HAVE ALREADY OCCURRED. THE HRRR SHOWS SOME
INTERMITTENT BREAKS IN CLOUDS OVER THE THE NORTHWEST PIEDMONT WITH
WESTERLY FLOW ALOFT AND NOT AS MUCH LOW-LEVEL MOISTURE THERE. NOT
CONFIDENT IN THE UPPER 40S THE HRRR GIVES...BUT THERE COULD BE A
LITTLE WARMING THROUGH EARLY AFTERNOON.
TONIGHT: THE SECOND BATCH OF S/W ENERGY MOVES INTO THE AREA BETWEEN
06 TO 12Z TUESDAY. RESULTANT WEAK DPVA AND SHALLOW ISENTROPIC
UPGLIDE WILL RE-NEW/DEEPEN SATURATION ALOFT TO SUPPORT SOME LIGHT
SNOW AND FLURRIES INTO THE AREA AROUND DAYBREAK ACROSS THE WESTERN
AND SOUTHERN PORTIONS OF THE FORECAST AREA. MODELS ARE ONLY
GENERATING A HUNDREDTH OR TWO ACROSS THE AREA SO NO ACCUMULATION ARE
EXPECTED. CAA WILL GOVERN LOWS TONIGHT...RANGING FROM UPPER TEENS
ACROSS THE NE TO MID 20S SOUTH.
TUESDAY AND TUESDAY NIGHT: TRANSITORY ARCTIC HIGH PRESSURE WILL HAVE
SETTLED ACROSS THE HEART OF CENTRAL NC BY TUESDAY MORNING. THIS HIGH
PRESSURE WILL BE NUDGED OFFSHORE BY LATE DAY AS A FAST MOVING SHORT
WAVE MOVES EAST ACROSS THE AREA. BRIEF SOUTHERLY FLOW AND WEAK
SUPPORT ALOFT WILL POTENTIALLY PRODUCE SOME LIGHT
SNOW/FLURRIES...MAINLY ACROSS THE SOUTHERN TIER AND THE WESTERN
PIEDMONT TUESDAY MORNING THROUGH AROUND MID DAY. OTHERWISE...SKIES
WILL REMAIN BE MOSTLY CLOUDY THROUGH THE DAY WITH HIGHS PEAKING IN
THE MID TO UPPER 30S. MINOR MODERATION IN MIN TEMPS IS EXPECTED TUE
NIGHT WITH DOWNSLOPE WARMING IN GENERALLY WESTERLY LOW LEVEL FLOW
AIDED BY STREAMING MID TO HIGH CLOUDINESS ALOFT IN THE FAST
CONFLUENT FLOW. MINS WILL BE MOSTLY IN THE MID 20S. -MLM
&&
.SHORT TERM /WEDNESDAY THROUGH THURSDAY/...
AS OF 355 PM MONDAY...
THERE IS STILL A BIT OF UNCERTAINTY WITH THE TRACK OF A LOW THAT
DEVELOPS OVER THE GULF AND MOVES NORTHEAST ALONG THE SOUTHEAST U.S.
COAST AND THUS THE CONFIDENCE IS BELOW AVERAGE. HOWEVER...GIVEN THAT
THE TRACK OF THE LOW IS NOT LIKELY TO SHIFT SIGNIFICANTLY...IT IS
LIKELY THAT SNOW WILL OCCUR OVER A PORTION OF CENTRAL NC WEDNESDAY
NIGHT THROUGH THURSDAY MORNING...WITH HIGH CHANCES OF RAIN OR SNOW
ACROSS THE ENTIRE AREA. KEEP IN MIND THOUGH THAT CHANGES IN THE LOW
TRACK WILL RESULT IN CHANGES TO THE P-TYPE...DURATION...AND AMOUNTS.
THE LATEST GFS ANALYZES THE LOW FARTHER EAST THAN THE ECMWF...
FAVORING LOWER RAIN/SNOW AMOUNTS BUT BETTER CHANCES FOR SNOW THAN
RAIN. SHOULD THE LOW TRACK BE FARTHER EAST IT WOULD FAVOR EVEN LESS
PRECIP. HOWEVER...A TRACK CLOSER TO THE CAROLINA COAST WOULD FAVOR
MORE PRECIP BUT HIGHER CHANCES OF RAIN THAN SNOW. REGARDLESS...
CURRENT FORECASTS SUGGEST A NOT SO NICE 12-24 HOUR PERIOD AND AS OF
THE LATEST FORECAST EXPECT SNOW ACCUMULATIONS OF UP TO 2 INCHES IN
THE NORTHEAST. TEMPERATURES WEDNESDAY AFTERNOON IN THE MID TO UPPER
40S WILL DECREASE INTO THE MID 20S NORTH TO AROUND 30 DEGREES SOUTH
WITH AT LEAST SOME SNOW POSSIBLE OVER THE ENTIRE CWA. TEMPERATURES
WILL RISE INTO THE UPPER 30S TO LOW 40S ON THURSDAY...WITH ALL
LINGERING PRECIPITATION CHANGING OVER TO RAIN BEFORE ENDING THURSDAY
EVENING/NIGHT. THE LOW WILL START TO MOVE AWAY FROM THE COAST...
ALLOWING HIGH PRESSURE TO BUILD IN. DESPITE THE LINGERING CLOUDS...
THE COLD ADVECTION SHOULD BE ENOUGH TO RESULT IN LOW TEMPS IN THE
LOW TO MID 20S ACROSS THE AREA THURSDAY NIGHT.
&&
.LONG TERM /FRIDAY THROUGH MONDAY/...
AS OF 255 PM MONDAY...
HIGH PRESSURE WILL BUILD EAST TOWARD NC ON FRIDAY...HOWEVER COLD AIR
ADVECTING INTO THE REGION WILL RESULT IN HIGHS ONLY IN THE MID 30S
NORTH TO AROUND 40 DEGREES SOUTHWEST. OVERNIGHT LOWS IN THE UPPER
TEENS TO LOW 20S EXPECTED FRIDAY NIGHT. BOTH THE GFS AND THE ECMWF
PREDICT HIGH PRESSURE TO TRAVERSE THE GREAT LAKES REGION DURING THIS
TIME PERIOD...RIDGING SOUTH INTO CENTRAL NC ON SATURDAY NIGHT AND
LINGERING THROUGH THE WEEKEND. THE BIG QUESTION WILL BE HOW LONG THE
WEDGE AIRMASS LINGERS OVER THE NORTHWEST...AND HOW THAT WILL IMPACT
BOTH TEMPERATURES AND WEATHER TOWARD THE END OF THE WEEKEND AND INTO
MONDAY. WITH SIGNIFICANT MODEL DIFFERENCES DURING THIS PART OF THE
FORECAST...CONFIDENCE REMAINS LOW. GENERALLY...EXPECT INCREASING
PRECIPITATION CHANCES FROM WEST TO EAST THROUGH MONDAY WITH
GRADUALLY MODERATING TEMPERATURES FROM UPPER 30S NW TO LOW 40S SE ON
SATURDAY TO MID 50S NW TO POSSIBLY LOW 60S SOUTH ON MONDAY.
&&
.AVIATION /18Z MONDAY THROUGH SATURDAY/...
AS OF 100 PM MONDAY...
PRIMARY AVIATION CONCERN NEXT 24 HRS: MVFR CIGS AT RDU/RWI/FAY
THROUGH EARLY THIS EVENING... THEN RETURNING TO INT/GSO TOWARD
MIDNIGHT... AND RETURNING TO RDU/RWI/FAY TUE MORNING.
A COLD FRONT HAS SETTLED SOUTHEAST OF CENTRAL NC EARLY THIS
AFTERNOON... AFTER BRINGING PATCHY RAIN AND SUB-VFR CIGS TO AREA
TERMINALS. CIGS AT INT/GSO HAVE RISEN TO VFR AS CHILLY HIGH PRESSURE
BEGINS TO BUILD IN FROM THE NORTH AND NW... HOWEVER MVFR CIGS
PERSIST AT RDU/FAY/RWI. AT INT/GSO... VFR CONDITIONS WILL HOLD UNTIL
AROUND 05Z OR 06Z... WHEN MVFR OR IFR CIGS WILL RETURN AND LIKELY
LINGER THROUGH THE END OF THE TAF VALID PERIOD. AT RDU/FAY/RWI...
MVFR CIGS SHOULD PERSIST UNTIL THE 02Z-05Z TIME FRAME... WHEN CIGS
SHOULD IMPROVE TO VFR. OCCASIONAL GUSTS ARE ALSO EXPECTED AT THESE
THREE SITES THIS AFTERNOON. VFR CONDITIONS SHOULD HOLD OVERNIGHT AT
THESE 3 SITES THROUGH DAYBREAK TUE AS THE HIGH PRESSURE CONTINUES TO
BUILD IN... BUT THEN AFTER 13Z TUE... AN APPROACHING DISTURBANCE
ALOFT TRACKING ACROSS THE GULF AND SOUTHEAST STATES WILL BRING A
RETURN TO MVFR OR IFR CONDITIONS STARTING MID MORNING TUE. A LITTLE
LIGHT SNOW IS POSSIBLE STARTING TUE MORNING... ESPECIALLY AT FAY...
HOWEVER AMOUNTS SHOULD BE VERY LIGHT... AND WHILE VSBYS MAY DROP TO
MVFR... THERE IS TOO MUCH UNCERTAINTY AT THIS RANGE TO INCLUDE THIS
IN THE TAFS AT THIS TIME... BUT STAY TUNED.
LOOKING BEYOND 18Z TUE... CONFIDENCE IS NOT HIGH IN THE DETAILS OF
THE FORECAST THROUGH MID WEEK... ALTHOUGH THE WEATHER IS LIKELY TO
REMAIN UNSETTLED. THE FRONTAL ZONE HOLDS JUST TO OUR SOUTHEAST...
WITH WAVES OF LOW PRESSURE OF VARYING STRENGTH TRACKING ALONG THE
FRONTAL ZONE. VFR CONDITIONS SHOULD BE NOTED AT ALL SITES BRIEFLY
TUE EVENING/NIGHT... BUT IFR FOG IS POSSIBLE WITH A MOIST AIR MASS
IN PLACE. THE STRONGEST LOW PRESSURE WAVE OF THIS SERIES WILL PASS
JUST TO OUR SOUTHEAST LATE WED THROUGH THU MORNING... AND THIS WILL
BRING THE NEXT GREATEST CHANCE FOR SUB-VFR CONDITIONS AND
PRECIPITATION (LIKELY A WINTRY MIX) MAINLY WED EVENING INTO EARLY
THU MORNING. SUB-IFR CONDITIONS MAY HOLD AT INT/GSO WITH LOW CLOUDS
AND FOG THU INTO FRI... WHILE VFR CONDITIONS ARE NOTED AT OTHER
SITES. CHILLY HIGH PRESSURE BUILDING IN FOR THE WEEKEND MAY FINALLY
ENSURE A PERIOD OF VFR CONDITIONS AT ALL SITES SATURDAY. -GIH
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...BLS/GIH
NEAR TERM...CBL/BLS/MLM
SHORT TERM...KC
LONG TERM...KC
AVIATION...HARTFIELD
AREA FORECAST DISCUSSION
NWS RALEIGH NC
100 PM EST MON FEB 23 2015
.SYNOPSIS..A COLD FRONT WILL SETTLE SOUTHEAST OF THE AREA THIS
AFTERNOON. A WEAK WAVE OF LOW PRESSURE WILL TRACK NORTHEASTWARD
ALONG THE FRONT TONIGHT THROUGH TUESDAY... AS ARCTIC HIGH PRESSURE
BUILDS INTO THE AREA FROM THE NORTH. A SECOND STRONGER LOW PRESSURE
AREA WILL TRACK ALONG THE FRONT MIDWEEK... MOVING JUST SOUTHEAST OF
THE AREA WEDNESDAY NIGHT THROUGH THURSDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 1015 AM MONDAY...
A LOW AMPLITUDE SHORTWAVE AND ASSOCIATED WEAK SURFACE LOW ARE
DEPARTING THE SC COAST THIS MORNING. ANAFRONTAL PRECIP MAINLY
SOUTHEAST OF THE TRIANGLE AREA WILL ALSO CONTINUE TO EXIT TO THE
EAST THROUGH EARLY AFTERNOON. WEAK COLD ADVECTION WILL PERSIST THIS
AFTERNOON BEFORE THE STRONGER SURGE OCCURS THIS EVENING AHEAD THE
ARCTIC HIGH BUILDING ACROSS THE CENTRAL APPALACHIANS. DUE TO THE
DELAYED ARRIVAL OF COLDER LOW-LEVEL AIR...THE WETBULB FREEZING LINE
IS STILL WELL TO OUR NORTH IN CENTRAL VA AND BY THE TIME IT SINKS
SOUTH IN THE NORTHERN COASTAL PLAIN THIS AFTERNOON... ALL DEEPER
MOISTURE AND PRECIP WILL EITHER HAVE DEPARTED OR PRECIP WON`T BE OF
SUFFICIENT INTENSITY TO CAUSE WETBULBING OR ANY WINTRY IMPACTS.
LATEST GUIDANCE REFLECTS THIS. WILL KEEP THE GENERAL TREND OF POPS
GOING AND JUST MAKE SOME ALTERATIONS TO ACCOUNT FOR LATEST
RADAR....WITH POPS ENDING AFTER 18Z. WILL ALSO HAVE AN EYE ON THE
POTENTIAL FOR A MESOSCALE BAND OF SHALLOW MOISTURE AND PRECIP (MOST
LIKELY SLEET BASED ON TEMPS AROUND -10C IN THE SHALLOW SATURATED
LAYER) IN THE 21Z TO 03Z TIME FRAME...THOUGH NO IMPACT WOULD BE
EXPECTED AT THIS TIME. HI-RES MODELS ARE STILL SPLIT ON WHETHER OR
NOT THIS WILL DEVELOP...BUT MODELS HAVE BEEN SHOWING SOMETHING OF
THIS NATURE FOR MULTIPLE RUNS.
REGARDING TEMPS...THICKNESSES WILL STEADILY FALL THROUGHOUT THE DAY
IN THE NORTHEAST FLOW...SO FOR MANY LOCATIONS HIGHS IN THE UPPER 30S
NORTH TO MID 40S SOUTH HAVE ALREADY OCCURRED. THE HRRR SHOWS SOME
INTERMITTENT BREAKS IN CLOUDS OVER THE THE NORTHWEST PIEDMONT WITH
WESTERLY FLOW ALOFT AND NOT AS MUCH LOW-LEVEL MOISTURE THERE. NOT
CONFIDENT IN THE UPPER 40S THE HRRR GIVES...BUT THERE COULD BE A
LITTLE WARMING THROUGH EARLY AFTERNOON.
TONIGHT: THE SECOND BATCH OF S/W ENERGY MOVES INTO THE AREA BETWEEN
06 TO 12Z TUESDAY. RESULTANT WEAK DPVA AND SHALLOW ISENTROPIC
UPGLIDE WILL RE-NEW/DEEPEN SATURATION ALOFT TO SUPPORT SOME LIGHT
SNOW AND FLURRIES INTO THE AREA AROUND DAYBREAK ACROSS THE WESTERN
AND SOUTHERN PORTIONS OF THE FORECAST AREA. MODELS ARE ONLY
GENERATING A HUNDREDTH OR TWO ACROSS THE AREA SO NO ACCUMULATION ARE
EXPECTED. CAA WILL GOVERN LOWS TONIGHT...RANGING FROM UPPER TEENS
ACROSS THE NE TO MID 20S SOUTH.
&&
.SHORT TERM /TUESDAY AND TUESDAY NIGHT/...
AS OF 330 AM MONDAY...
TRANSITORY ARCTIC HIGH PRESSURE WILL HAVE SETTLED ACROSS THE HEART
OF CENTRAL NC BY TUESDAY MORNING. THIS HIGH PRESSURE WILL BE NUDGED
OFFSHORE BY LATE DAY AS A FAST MOVING SHORT WAVE MOVES EAST ACROSS
THE AREA. BRIEF SOUTHERLY FLOW AND WEAK SUPPORT ALOFT WILL
POTENTIALLY PRODUCE SOME LIGHT SNOW/FLURRIES...MAINLY ACROSS THE
SOUTHERN TIER AND THE WESTERN PIEDMONT TUESDAY MORNING THROUGH
AROUND MID DAY. OTHERWISE...SKIES WILL REMAIN BE MOSTLY CLOUDY
THROUGH THE DAY WITH HIGHS PEAKING IN THE MID TO UPPER 30S. MINOR
MODERATION IN MIN TEMPS IS EXPECTED TUE NIGHT WITH DOWNSLOPE WARMING
IN GENERALLY WESTERLY LOW LEVEL FLOW AIDED BY STREAMING MID TO HIGH
CLOUDINESS ALOFT IN THE FAST CONFLUENT FLOW. MINS WILL BE MOSTLY IN
THE MID 20S.
&&
.LONG TERM /WEDNESDAY THROUGH SUNDAY/...
AS OF 330 AM MONDAY...
A SOUTHERN STREAM SHORT WAVE MOVING ACROSS THE SOUTHEASTERN GULF
STATES HAS BEEN ADVERTISED FOR THE MIDWEEK FOR THE PAST FEW DAYS.
THIS SHORT WAVE WILL INDUCE CYCLOGENESIS ALONG THE SOUTHERN STREAM
MOISTURE PLUME/STALLED FRONTAL ZONE. THE RESULTING LOW WILL MOVE
NORTHEAST ACROSS NORTHERN FLORIDA AND GRAZE THE AREA AS IT MOVES OFF
INTO THE MID ATLANTIC. RAIN WILL SPREAD INTO THE SOUTHERN TIER AS
EARLY AS WEDNESDAY AFTERNOON...WITH BETTER CHANCES DURING THE
OVERNIGHT. COLD AIR WILL BE SURGING SOUTH BEHIND THE LOW...AND
EXPECT A SOUTHERLY TRANSITION TO SNOW OVERNIGHT AS MINS FALL INTO
THE MID AND UPPER 20S. A CHANCE OF SNOW WILL LINGER INTO THURSDAY
MORNING EAST OF INTERSTATE 95...OTHERWISE SKIES WILL REMAIN CLOUDY
WITH HIGHS SUFFERING ANOTHER SETBACK AS REINFORCING HIGH PRESSURE
AGAIN SETTLES DOWN THE COAST. THURSDAYS HIGHS WILL BE IN THE UPPER
30S NORTH TO LOWER 40S SOUTH.
HAVE LITTLE CONFIDENCE IN NAILING DOWN THE FEATURES OF POTENTIAL
PRECIP PRODUCING SYSTEMS AS THE WEEKEND APPROACHES IN THIS STUBBORN
SPLIT FLOW REGIME...I.E. EVOLUTION AND TIMING OF NORTHERN VS
SOUTHERN STREAM FEATURES AND THEIR REFUSAL TO COME INTO PHASE.
CONFIDENCE IS HIGH THAT HIGHS FRIDAY THROUGH SUNDAY WILL REMAIN
WELL BELOW NORMAL...GENERALLY IN THE UPPER 30S TO LOWER 40S FRIDAY
AND SATURDAY...AND LOW AMPLITUDE RIDGING LATE THIS WEEKEND WILL
PRODUCE A WARMUP SUNDAY...WITH PERHAPS NEAR NORMAL HIGHS ON MONDAY.
&&
.AVIATION /18Z MONDAY THROUGH SATURDAY/...
AS OF 100 PM MONDAY...
PRIMARY AVIATION CONCERN NEXT 24 HRS: MVFR CIGS AT RDU/RWI/FAY
THROUGH EARLY THIS EVENING... THEN RETURNING TO INT/GSO TOWARD
MIDNIGHT... AND RETURNING TO RDU/RWI/FAY TUE MORNING.
A COLD FRONT HAS SETTLED SOUTHEAST OF CENTRAL NC EARLY THIS
AFTERNOON... AFTER BRINGING PATCHY RAIN AND SUB-VFR CIGS TO AREA
TERMINALS. CIGS AT INT/GSO HAVE RISEN TO VFR AS CHILLY HIGH PRESSURE
BEGINS TO BUILD IN FROM THE NORTH AND NW... HOWEVER MVFR CIGS
PERSIST AT RDU/FAY/RWI. AT INT/GSO... VFR CONDITIONS WILL HOLD UNTIL
AROUND 05Z OR 06Z... WHEN MVFR OR IFR CIGS WILL RETURN AND LIKELY
LINGER THROUGH THE END OF THE TAF VALID PERIOD. AT RDU/FAY/RWI...
MVFR CIGS SHOULD PERSIST UNTIL THE 02Z-05Z TIME FRAME... WHEN CIGS
SHOULD IMPROVE TO VFR. OCCASIONAL GUSTS ARE ALSO EXPECTED AT THESE
THREE SITES THIS AFTERNOON. VFR CONDITIONS SHOULD HOLD OVERNIGHT AT
THESE 3 SITES THROUGH DAYBREAK TUE AS THE HIGH PRESSURE CONTINUES TO
BUILD IN... BUT THEN AFTER 13Z TUE... AN APPROACHING DISTURBANCE
ALOFT TRACKING ACROSS THE GULF AND SOUTHEAST STATES WILL BRING A
RETURN TO MVFR OR IFR CONDITIONS STARTING MID MORNING TUE. A LITTLE
LIGHT SNOW IS POSSIBLE STARTING TUE MORNING... ESPECIALLY AT FAY...
HOWEVER AMOUNTS SHOULD BE VERY LIGHT... AND WHILE VSBYS MAY DROP TO
MVFR... THERE IS TOO MUCH UNCERTAINTY AT THIS RANGE TO INCLUDE THIS
IN THE TAFS AT THIS TIME... BUT STAY TUNED.
LOOKING BEYOND 18Z TUE... CONFIDENCE IS NOT HIGH IN THE DETAILS OF
THE FORECAST THROUGH MID WEEK... ALTHOUGH THE WEATHER IS LIKELY TO
REMAIN UNSETTLED. THE FRONTAL ZONE HOLDS JUST TO OUR SOUTHEAST...
WITH WAVES OF LOW PRESSURE OF VARYING STRENGTH TRACKING ALONG THE
FRONTAL ZONE. VFR CONDITIONS SHOULD BE NOTED AT ALL SITES BRIEFLY
TUE EVENING/NIGHT... BUT IFR FOG IS POSSIBLE WITH A MOIST AIR MASS
IN PLACE. THE STRONGEST LOW PRESSURE WAVE OF THIS SERIES WILL PASS
JUST TO OUR SOUTHEAST LATE WED THROUGH THU MORNING... AND THIS WILL
BRING THE NEXT GREATEST CHANCE FOR SUB-VFR CONDITIONS AND
PRECIPITATION (LIKELY A WINTRY MIX) MAINLY WED EVENING INTO EARLY
THU MORNING. SUB-IFR CONDITIONS MAY HOLD AT INT/GSO WITH LOW CLOUDS
AND FOG THU INTO FRI... WHILE VFR CONDITIONS ARE NOTED AT OTHER
SITES. CHILLY HIGH PRESSURE BUILDING IN FOR THE WEEKEND MAY FINALLY
ENSURE A PERIOD OF VFR CONDITIONS AT ALL SITES SATURDAY. -GIH
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...BLS/GIH
NEAR TERM...CBL/BLS
SHORT TERM...MLM
LONG TERM...MLM
AVIATION...HARTFIELD
AREA FORECAST DISCUSSION
NWS TULSA OK
1112 AM CST MON FEB 23 2015
.AVIATION...
CONCERNING TAF SITES KTUL/KRVS/KBVO/KMLC/KXNA/KFYV/KFSM/KROG.
FOR THE 18Z TAFS... INTERMITTENT SNOW SHOWERS WILL CONTINUE TO AFFECT
ALL SITES THIS AFTERNOON... CREATING TEMPORARY MVFR CONDITIONS. A
BRIEF PERIOD OF IFR CONDITIONS MAY BE A POSSIBILITY WITH ANY AREAS
OF HEAVIER PRECIPITATION THAT HAPPEN TO PASS OVER A TERMINAL SITE.
PRECIPITATION WILL END FROM WEST TO EAST LATE THIS AFTERNOON. WHILE
CONDITIONS SLOWLY IMPROVE ACROSS EASTERN OKLAHOMA... MVFR CEILINGS
ARE EXPECTED TO PREVAIL THROUGHOUT THE FORECAST PERIOD AT ARKANSAS
SITES.
&&
.PREV DISCUSSION... /ISSUED 1056 AM CST MON FEB 23 2015/
..UPDATE...
DISCUSSION...
THE HEAVIEST PRECIPITATION CONTINUES TO WORK ITS WAY EAST ACROSS
THE FORECAST AREA AND IS ENTERING WEST CENTRAL ARKANSAS. AREAS ALONG
AND SOUTH OF INTERSTATE 40 WILL SEE THE BULK OF ACTIVITY FOR THE
REMAINDER OF THE DAY. SCATTERED AREAS OF LIGHT PRECIPITATION
CONTINUE TO DEVELOP WEST OF THE FORECAST AREA WHICH WILL CONTINUE
TO PRODUCE INTERMITTENT ACTIVITY ACROSS MUCH OF THE REMAINDER OF
OUR AREA. AS SUCH... HAVE NOT CHANGED POPS OR FORECAST
TEMPERATURES FOR THIS AFTERNOON.
PREV DISCUSSION... /ISSUED 539 AM CST MON FEB 23 2015/
AVIATION...
CONCERNING TAF SITES KTUL/KRVS/KBVO/KMLC/KXNA/KFYV/KFSM/KROG.
WIDESPREAD LIGHT SNOW WILL TRACK ACROSS NE OK / FAR NW AR WITH
MINIMAL FLIGHT IMPACTS EXPECTED. MORE WIDESPREAD AND PROLONGED
AVIATION IMPACTS ARE EXPECTED ACROSS SE OK INTO WEST CENTRAL
ARKANSAS W/ MVFR TO IFR CONDITIONS LIKELY. PRECIP WILL DIMINISH BY
EARLY EVENING WITH A TREND TOWARD VFR / MVFR CEILINGS.
PREV DISCUSSION... /ISSUED 406 AM CST MON FEB 23 2015/
DISCUSSION...
ANOTHER ROUND OF WINTER WEATHER IS ABOUT TO GET UNDERWAY ACROSS
PARTS OF EASTERN OK EARLY THIS MORNING. A LARGE AREA OF SHOWERY
PRECIP HAS SPREAD ACROSS WESTERN/CENTRAL OK A LITTLE AHEAD OF
SCHEDULE...WITH SEVERAL REPORTS OF GRAUPEL OR ICE PELLETS DESPITE
ALL MODEL SOUNDINGS POINTING TO SNOW. STILL BELIEVE THIS WILL
MAINLY BE A SNOW EVENT FOR ALL BUT FAR SOUTHERN OK BUT THE
CONVECTIVE NATURE OF AT LEAST THIS EARLY ROUND OF PRECIP LENDS SOME
CONFIDENCE TO ADDING A SLEET/SNOW MIXTURE NORTH TO ABOUT I-40 THIS
MORNING. OVERALL CONFIGURATION AND TIMING OF ADVISORY APPEARS GOOD
FOR NOW...THOUGH MUCH OF THE EVENT MAY BE DONE WELL BEFORE 00Z
EXPIRATION TIME. LATEST RUNS OF HRRR HAVE ALSO SPREAD HEAVIER SNOW
TOTALS A BIT FARTHER NORTH ACROSS EASTERN OK AND THIS WILL NEED TO
BE WATCHED THROUGHOUT THE DAY. TEMPS TODAY WILL NOT GO MUCH OF
ANYWHERE WITH MOSTLY LOW/MID 20S FOR HIGHS.
COLD AND DRY TONIGHT WITH A MODEST WARM UP ON TUESDAY...WHICH WILL
FEEL NICE AFTER LAST COUPLE OF DAYS DESPITE BEING SEVERAL DEGREES
BELOW NORMAL. UPPER LEVEL SYSTEM OVER THE SOUTHWEST WILL MOVE EAST
ACROSS TEXAS TUE NIGHT INTO WED...WITH A SMALL CHANCE OF PRECIP
SPREADING INTO SE OKLAHOMA DURING THAT TIME IN THE FORM OF LIGHT
SNOW OR SLEET. THIS IS NOT EXPECTED TO BE MUCH OF AN ISSUE AS THE
HEAVIER PRECIP SHOULD STAY SOUTH OF THE RED RIVER. A NICE WARM UP
FOR WEDNESDAY BUT NOT FOR LONG AS ANOTHER SURGE OF MUCH COLDER AIR
PLUNGES SOUTH BY THURSDAY.
HIGH LEVELS OF UNCERTAINTY IN THE EXTENDED FORECAST BUT IT DOES
APPEAR THAT TEMPS WILL WARM UP BY NEXT WEEKEND...ENOUGH FOR ANY
PRECIP TO BE LIQUID. THERE STILL MAY BE A TRANSITION PERIOD LATE
IN THE WEEK HOWEVER SO WINTER WEATHER POTENTIAL WILL STILL BE
PRESENT FOR THU INTO SAT. FORECAST CONFIDENCE REMAINS QUITE LOW
BEYOND THURSDAY.
&&
.TSA WATCHES/WARNINGS/ADVISORIES...
OK...WINTER WEATHER ADVISORY UNTIL 6 PM MONDAY FOR OKZ049-OKZ053-
OKZ065-OKZ066-OKZ070-OKZ071-OKZ072-OKZ073-OKZ074-OKZ075-
OKZ076.
AR...WINTER WEATHER ADVISORY UNTIL 6 PM MONDAY FOR ARZ019-ARZ020-
ARZ029.
&&
$$
AVIATION...06
AREA FORECAST DISCUSSION
NWS TULSA OK
1056 AM CST MON FEB 23 2015
...UPDATE...
.DISCUSSION...
THE HEAVIEST PRECIPITATION CONTINUES TO WORK ITS WAY EAST ACROSS
THE FORECAST AREA AND IS ENTERING WEST CENTRAL ARKANSAS. AREAS ALONG
AND SOUTH OF INTERSTATE 40 WILL SEE THE BULK OF ACTIVITY FOR THE
REMAINDER OF THE DAY. SCATTERED AREAS OF LIGHT PRECIPITATION
CONTINUE TO DEVELOP WEST OF THE FORECAST AREA WHICH WILL CONTINUE
TO PRODUCE INTERMITTENT ACTIVITY ACROSS MUCH OF THE REMAINDER OF
OUR AREA. AS SUCH... HAVE NOT CHANGED POPS OR FORECAST
TEMPERATURES FOR THIS AFTERNOON.
&&
.PREV DISCUSSION... /ISSUED 539 AM CST MON FEB 23 2015/
AVIATION...
CONCERNING TAF SITES KTUL/KRVS/KBVO/KMLC/KXNA/KFYV/KFSM/KROG.
WIDESPREAD LIGHT SNOW WILL TRACK ACROSS NE OK / FAR NW AR WITH
MINIMAL FLIGHT IMPACTS EXPECTED. MORE WIDESPREAD AND PROLONGED
AVIATION IMPACTS ARE EXPECTED ACROSS SE OK INTO WEST CENTRAL
ARKANSAS W/ MVFR TO IFR CONDITIONS LIKELY. PRECIP WILL DIMINISH BY
EARLY EVENING WITH A TREND TOWARD VFR / MVFR CEILINGS.
PREV DISCUSSION... /ISSUED 406 AM CST MON FEB 23 2015/
DISCUSSION...
ANOTHER ROUND OF WINTER WEATHER IS ABOUT TO GET UNDERWAY ACROSS
PARTS OF EASTERN OK EARLY THIS MORNING. A LARGE AREA OF SHOWERY
PRECIP HAS SPREAD ACROSS WESTERN/CENTRAL OK A LITTLE AHEAD OF
SCHEDULE...WITH SEVERAL REPORTS OF GRAUPEL OR ICE PELLETS DESPITE
ALL MODEL SOUNDINGS POINTING TO SNOW. STILL BELIEVE THIS WILL
MAINLY BE A SNOW EVENT FOR ALL BUT FAR SOUTHERN OK BUT THE
CONVECTIVE NATURE OF AT LEAST THIS EARLY ROUND OF PRECIP LENDS SOME
CONFIDENCE TO ADDING A SLEET/SNOW MIXTURE NORTH TO ABOUT I-40 THIS
MORNING. OVERALL CONFIGURATION AND TIMING OF ADVISORY APPEARS GOOD
FOR NOW...THOUGH MUCH OF THE EVENT MAY BE DONE WELL BEFORE 00Z
EXPIRATION TIME. LATEST RUNS OF HRRR HAVE ALSO SPREAD HEAVIER SNOW
TOTALS A BIT FARTHER NORTH ACROSS EASTERN OK AND THIS WILL NEED TO
BE WATCHED THROUGHOUT THE DAY. TEMPS TODAY WILL NOT GO MUCH OF
ANYWHERE WITH MOSTLY LOW/MID 20S FOR HIGHS.
COLD AND DRY TONIGHT WITH A MODEST WARM UP ON TUESDAY...WHICH WILL
FEEL NICE AFTER LAST COUPLE OF DAYS DESPITE BEING SEVERAL DEGREES
BELOW NORMAL. UPPER LEVEL SYSTEM OVER THE SOUTHWEST WILL MOVE EAST
ACROSS TEXAS TUE NIGHT INTO WED...WITH A SMALL CHANCE OF PRECIP
SPREADING INTO SE OKLAHOMA DURING THAT TIME IN THE FORM OF LIGHT
SNOW OR SLEET. THIS IS NOT EXPECTED TO BE MUCH OF AN ISSUE AS THE
HEAVIER PRECIP SHOULD STAY SOUTH OF THE RED RIVER. A NICE WARM UP
FOR WEDNESDAY BUT NOT FOR LONG AS ANOTHER SURGE OF MUCH COLDER AIR
PLUNGES SOUTH BY THURSDAY.
HIGH LEVELS OF UNCERTAINTY IN THE EXTENDED FORECAST BUT IT DOES
APPEAR THAT TEMPS WILL WARM UP BY NEXT WEEKEND...ENOUGH FOR ANY
PRECIP TO BE LIQUID. THERE STILL MAY BE A TRANSITION PERIOD LATE
IN THE WEEK HOWEVER SO WINTER WEATHER POTENTIAL WILL STILL BE
PRESENT FOR THU INTO SAT. FORECAST CONFIDENCE REMAINS QUITE LOW
BEYOND THURSDAY.
&&
.TSA WATCHES/WARNINGS/ADVISORIES...
OK...WINTER WEATHER ADVISORY UNTIL 6 PM MONDAY FOR OKZ049-OKZ053-
OKZ065-OKZ066-OKZ070-OKZ071-OKZ072-OKZ073-OKZ074-OKZ075-
OKZ076.
AR...WINTER WEATHER ADVISORY UNTIL 6 PM MONDAY FOR ARZ019-ARZ020-
ARZ029.
&&
$$
SHORT TERM...06
AREA FORECAST DISCUSSION
NWS AUSTIN/SAN ANTONIO TX
1152 AM CST MON FEB 23 2015
.AVIATION...
FREEZING TEMPERATURES WILL REMAIN ALONG AND NORTH OF A KDRT TO
KHDO TO KHYI TO KGYB LINE THIS AFTERNOON INTO THIS EVENING. THE
PORTION EAST OF KHDO SAGS SOUTH TO A KSAT TO KENEDY TO K66R LINE
BY SUNRISE TUESDAY AND THEN MOVES BACK TO NORTH TUESDAY. PATCHY
-DZ PERSISTS THIS AFTERNOON AND SLOWLY SHIFTS INTO EASTERN AREAS
TONIGHT INTO TUESDAY WITH -FZDZ NORTH OF THE FREEZE LINE. HAVE
CONTINUED -FZDZ FOR KAUS THROUGH MIDDAY TUESDAY AND -DZ FOR
KSAT/KSSF THROUGH THIS EVENING. SOME ICING IS POSSIBLE FROM JUST
ABOVE THE GROUND UP TO 4K FEET. OTHERWISE...IFR/MVFR CIGS PREVAIL
THIS AFTERNOON THROUGH TUESDAY. NLY WINDS 12 TO 17 KTS WITH GUSTS
TO 25 KTS PREVAIL THIS AFTERNOON...THEN DECREASE TO LESS THAN 10
KTS TONIGHT...THEN SLOWLY TURN TO NELY ON TUESDAY. EXCEPT...ALONG
THE RIO GRANDE WHERE THE TURN TO NELY AND ELY TAKES PLACE TONIGHT.
&&
.PREV DISCUSSION... /ISSUED 530 AM CST MON FEB 23 2015/
AVIATION UPDATE...FOR 12Z TAF PACKAGE...
CURRENT CONDITIONS WILL LIKELY PERSIST THROUGH ENTIRE TAF PERIOD.
THERE IS SOME CONCERN FOR -FZDZ THIS MORNING FOR KAUS SO INCLUDED
TEMPO GROUP TO HANDLE THAT. OTHERWISE -DZ EXPECTED FOR ALL
TERMINALS TODAY. AS PREVIOUS FORECAST MENTIONED...ICING WILL BE A
CONCERN FOR THE LOWEST 3KFT JUST OFF THE SURFACE DURING TAKEOFF AND
LANDING FOR ALL TERMINALS. OTHERWISE...MVFR/IFR CEILINGS ARE
EXPECTED THROUGHOUT THE DAY AND NIGHT. GUSTY WINDS WILL ALSO
PERSIST THROUGH THE DAY.
PREV DISCUSSION... /ISSUED 457 AM CST MON FEB 23 2015/
SHORT TERM (TODAY THROUGH TUESDAY)...
EARLY MORNING OBSERVATIONS SHOW THE FREEZING LINE ROUGHLY ALONG A
GEORGETOWN TO BOERNE TO COMSTOCK LINE. OBSERVATIONS ALSO SHOW
LIGHT MIXED PRECIPITATION FALLING ACROSS THE HILL COUNTRY WITH
ONLY TRACE AMOUNTS REPORTED SO FAR. OTHERWISE...RADAR ECHOES
GENERALLY ON THE INCREASE EARLY THIS MORNING...ESPECIALLY ACROSS
THE NORTHERN HILL COUNTRY INCLUDING KERR...GILLESPIE...LLANO AND
BURNET COUNTIES. THE LATEST HRRR AND NAM12 MODELS TEND TO FAVOR
THE ABOVE MENTIONED AREAS FOR PRECIPITATION TODAY AND WE HAVE
PLACED THE HIGHEST CHANCE FOR WINTRY PRECIPITATION HERE. WE/LL
NEED TO MONITOR THESE AREAS CAREFULLY AS ICE ACCUMULATIONS COULD
ADD UP QUICKER IF MULTIPLE ROUNDS OF PRECIPITATION DEVELOP.
OTHERWISE...WE STILL EXPECT WINTRY PRECIPITATION IN THE FORM OF
FREEZING RAIN TO OCCUR ACROSS THE SOUTHERN EDWARDS PLATEAU...HILL
COUNTRY AND PORTIONS OF THE INTERSTATE 35 CORRIDOR MAINLY NORTH OF
SAN MARCOS. WE STILL EXPECT ICE ACCUMULATIONS TO REMAIN AT OR
BELOW 1/10 OF AN INCH...WITH THE MAIN IMPACTS BEING ON BRIDGES AND
ELEVATED ROADWAYS. THE WINTER WEATHER ADVISORY WILL REMAIN IN
EFFECT UNTIL 6 PM TODAY.
OTHERWISE...TEMPERATURES WILL EITHER REMAIN STEADY OF SLOWLY FALL
TODAY DUE TO THE COMBINATION OF COLD AIR ADVECTION...CLOUD COVER
AND LIGHT PRECIPITATION. FOR THE EVENING AND OVERNIGHT HOURS...WE
EXPECT A FAIRLY QUICK DECREASE IN PRECIPITATION CHANCES FROM WEST
TO EAST ACROSS THE REGION. WE CONTEMPLATED EXPANDING THE WINTER
WEATHER ADVISORY FARTHER EAST TO COVER AREAS MAINLY NORTH OF
I-10/EAST OF I-35. HOWEVER...THE MODELS HAVE BEEN CONSISTENT IN
SHOWING A RATHER QUICK DECREASE IN THE PRECIPITATION THIS EVENING.
WE/LL CONTINUE TO HIGHLIGHT THIS REGION IN A SPECIAL WEATHER
STATEMENT TO COVER THE COLD TEMPERATURES AND POTENTIAL FOR LIGHT
WINTRY PRECIPITATION. PRECIPITATION CHANCES TEMPORARILY DECREASE
ON TUESDAY AS MID-LEVEL DRYING/WEAK SUBSIDENCE MOVE IN FROM THE
WEST.
LONG TERM (TUESDAY NIGHT THROUGH SUNDAY)...
ANOTHER UPPER LEVEL TROUGH APPROACHES SOUTH CENTRAL TEXAS FROM THE
WEST TUESDAY NIGHT. THE LATEST ROUND OF MODEL GUIDANCE IS SHOWING
THIS SYSTEM TO BE A LITTLE STRONGER WHEN COMPARED TO PREVIOUS
RUNS. WE HAVE INCREASED PRECIPITATION CHANCES SLIGHTLY FOR TUESDAY
NIGHT AND WEDNESDAY. AT THIS TIME...TEMPERATURES ARE EXPECTED TO
REMAIN ABOVE FREEZING TUESDAY NIGHT...SO WE/LL KEEP THE
PRECIPITATION AS ALL LIQUID. AS THE ABOVE MENTIONED UPPER LEVEL
STORM SYSTEM DEPARTS THE REGION BY LATE WEDNESDAY... ANOTHER
SYSTEM MOVES THROUGH ON THURSDAY. WE/LL KEEP THE FORECAST DRY AS
MOISTURE WILL BE LACKING. WE DO EXPECT ANOTHER SHOT OF COOLER AIR
TO MOVE THROUGH ON THURSDAY...FOLLOWED BY COOLER TEMPERATURES ON
FRIDAY. WE/LL KEEP A SLIGHT CHANCE FOR LIGHT RAIN IN THE FORECAST
FRIDAY THROUGH SUNDAY AS SOUTHERLY FLOW JUST ABOVE THE COLD
SURFACE AIR BEGINS TO SET UP A WARM AIR ADVECTION PATTERN.
&&
.PRELIMINARY POINT TEMPS/POPS...
AUSTIN CAMP MABRY 33 30 43 36 58 / 70 30 20 30 30
AUSTIN BERGSTROM INTL AIRPORT 34 30 43 34 57 / 70 30 20 30 30
NEW BRAUNFELS MUNI AIRPORT 36 30 45 37 61 / 60 30 10 30 20
BURNET MUNI AIRPORT 31 26 41 34 57 / 80 30 20 30 20
DEL RIO INTL AIRPORT 38 34 52 41 68 / 50 10 10 10 -
GEORGETOWN MUNI AIRPORT 33 27 42 34 56 / 70 40 20 30 30
HONDO MUNI AIRPORT 37 32 48 38 65 / 50 20 10 20 -
SAN MARCOS MUNI AIRPORT 35 30 44 37 59 / 70 30 10 30 20
LA GRANGE - FAYETTE REGIONAL 38 31 43 38 57 / 70 40 20 30 30
SAN ANTONIO INTL AIRPORT 38 31 45 38 62 / 60 30 10 20 10
STINSON MUNI AIRPORT 39 32 46 39 63 / 60 30 10 20 10
&&
.EWX WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY UNTIL 6 PM CST THIS EVENING FOR THE
FOLLOWING COUNTIES: BANDERA...BLANCO...BURNET...EDWARDS...
GILLESPIE...HAYS...KENDALL...KERR...LLANO...REAL...TRAVIS...VAL
VERDE...WILLIAMSON.
&&
$$
MESOSCALE/AVIATION...04
SYNOPTIC/GRIDS...17
PUBLIC SERVICE/DATA COLLECTION...00
AREA FORECAST DISCUSSION...UPDATED
NWS AUSTIN/SAN ANTONIO TX
1141 AM CST MON FEB 23 2015
.UPDATE...
LIGHT FREEZING RAIN/DRIZZLE CONTINUE TO AFFECT THE NORTHEAST PART
OF SOUTH CENTRAL TEXAS LATE THIS MORNING. CURRENTLY TEMPERATURES
ARE IN THE UPPER 20S AND LOWER 30S ACROSS THOSE LOCATIONS. AREA RADARS
AND HIRES MODEL SOLUTIONS ARE ENDING PRECIPITATION BY NOON OR 1
PM THIS AFTERNOON ACROSS MOST AREAS. HOWEVER...THERE IS A SLIGHT CHANCE
FOR FREEZING DRIZZLE ACROSS THE NORTHERN PORTION OF THE HILL
COUNTRY...ESPECIALLY...NORTH OF A LLANO TO LAKEWAY TO TAYLOR LINE.
TEMPERATURES WILL REMAIN IN THE UPPER 20S AND LOWER 30S FOR THE
REMAINDER OF THE DAY ACROSS THE HILL COUNTRY AND MID TO UPPER 30S
EAST OF THE I35 CORRIDOR. ICE ACCUMULATIONS ARE NOT
EXPECTED...HOWEVER...A THIN LAYER OF ICING ON THE GROUND...MAY BE
POSSIBLE OVER SOME LOCATIONS AND RESULTING IN MINOR TRAVEL
IMPACTS.
&&
.PREV DISCUSSION... /ISSUED 530 AM CST MON FEB 23 2015/
AVIATION UPDATE...FOR 12Z TAF PACKAGE...
CURRENT CONDITIONS WILL LIKELY PERSIST THROUGH ENTIRE TAF PERIOD.
THERE IS SOME CONCERN FOR -FZDZ THIS MORNING FOR KAUS SO INCLUDED
TEMPO GROUP TO HANDLE THAT. OTHERWISE -DZ EXPECTED FOR ALL
TERMINALS TODAY. AS PREVIOUS FORECAST MENTIONED...ICING WILL BE A
CONCERN FOR THE LOWEST 3KFT JUST OFF THE SURFACE DURING TAKEOFF AND
LANDING FOR ALL TERMINALS. OTHERWISE...MVFR/IFR CEILINGS ARE
EXPECTED THROUGHOUT THE DAY AND NIGHT. GUSTY WINDS WILL ALSO
PERSIST THROUGH THE DAY.
PREV DISCUSSION... /ISSUED 457 AM CST MON FEB 23 2015/
SHORT TERM (TODAY THROUGH TUESDAY)...
EARLY MORNING OBSERVATIONS SHOW THE FREEZING LINE ROUGHLY ALONG A
GEORGETOWN TO BOERNE TO COMSTOCK LINE. OBSERVATIONS ALSO SHOW
LIGHT MIXED PRECIPITATION FALLING ACROSS THE HILL COUNTRY WITH
ONLY TRACE AMOUNTS REPORTED SO FAR. OTHERWISE...RADAR ECHOES
GENERALLY ON THE INCREASE EARLY THIS MORNING...ESPECIALLY ACROSS
THE NORTHERN HILL COUNTRY INCLUDING KERR...GILLESPIE...LLANO AND
BURNET COUNTIES. THE LATEST HRRR AND NAM12 MODELS TEND TO FAVOR
THE ABOVE MENTIONED AREAS FOR PRECIPITATION TODAY AND WE HAVE
PLACED THE HIGHEST CHANCE FOR WINTRY PRECIPITATION HERE. WE/LL
NEED TO MONITOR THESE AREAS CAREFULLY AS ICE ACCUMULATIONS COULD
ADD UP QUICKER IF MULTIPLE ROUNDS OF PRECIPITATION DEVELOP.
OTHERWISE...WE STILL EXPECT WINTRY PRECIPITATION IN THE FORM OF
FREEZING RAIN TO OCCUR ACROSS THE SOUTHERN EDWARDS PLATEAU...HILL
COUNTRY AND PORTIONS OF THE INTERSTATE 35 CORRIDOR MAINLY NORTH OF
SAN MARCOS. WE STILL EXPECT ICE ACCUMULATIONS TO REMAIN AT OR
BELOW 1/10 OF AN INCH...WITH THE MAIN IMPACTS BEING ON BRIDGES AND
ELEVATED ROADWAYS. THE WINTER WEATHER ADVISORY WILL REMAIN IN
EFFECT UNTIL 6 PM TODAY.
OTHERWISE...TEMPERATURES WILL EITHER REMAIN STEADY OF SLOWLY FALL
TODAY DUE TO THE COMBINATION OF COLD AIR ADVECTION...CLOUD COVER
AND LIGHT PRECIPITATION. FOR THE EVENING AND OVERNIGHT HOURS...WE
EXPECT A FAIRLY QUICK DECREASE IN PRECIPITATION CHANCES FROM WEST
TO EAST ACROSS THE REGION. WE CONTEMPLATED EXPANDING THE WINTER
WEATHER ADVISORY FARTHER EAST TO COVER AREAS MAINLY NORTH OF
I-10/EAST OF I-35. HOWEVER...THE MODELS HAVE BEEN CONSISTENT IN
SHOWING A RATHER QUICK DECREASE IN THE PRECIPITATION THIS EVENING.
WE/LL CONTINUE TO HIGHLIGHT THIS REGION IN A SPECIAL WEATHER
STATEMENT TO COVER THE COLD TEMPERATURES AND POTENTIAL FOR LIGHT
WINTRY PRECIPITATION. PRECIPITATION CHANCES TEMPORARILY DECREASE
ON TUESDAY AS MID-LEVEL DRYING/WEAK SUBSIDENCE MOVE IN FROM THE
WEST.
LONG TERM (TUESDAY NIGHT THROUGH SUNDAY)...
ANOTHER UPPER LEVEL TROUGH APPROACHES SOUTH CENTRAL TEXAS FROM THE
WEST TUESDAY NIGHT. THE LATEST ROUND OF MODEL GUIDANCE IS SHOWING
THIS SYSTEM TO BE A LITTLE STRONGER WHEN COMPARED TO PREVIOUS
RUNS. WE HAVE INCREASED PRECIPITATION CHANCES SLIGHTLY FOR TUESDAY
NIGHT AND WEDNESDAY. AT THIS TIME...TEMPERATURES ARE EXPECTED TO
REMAIN ABOVE FREEZING TUESDAY NIGHT...SO WE/LL KEEP THE
PRECIPITATION AS ALL LIQUID. AS THE ABOVE MENTIONED UPPER LEVEL
STORM SYSTEM DEPARTS THE REGION BY LATE WEDNESDAY... ANOTHER
SYSTEM MOVES THROUGH ON THURSDAY. WE/LL KEEP THE FORECAST DRY AS
MOISTURE WILL BE LACKING. WE DO EXPECT ANOTHER SHOT OF COOLER AIR
TO MOVE THROUGH ON THURSDAY...FOLLOWED BY COOLER TEMPERATURES ON
FRIDAY. WE/LL KEEP A SLIGHT CHANCE FOR LIGHT RAIN IN THE FORECAST
FRIDAY THROUGH SUNDAY AS SOUTHERLY FLOW JUST ABOVE THE COLD
SURFACE AIR BEGINS TO SET UP A WARM AIR ADVECTION PATTERN.
&&
.PRELIMINARY POINT TEMPS/POPS...
AUSTIN CAMP MABRY 33 30 43 36 58 / 70 30 20 30 30
AUSTIN BERGSTROM INTL AIRPORT 34 30 43 34 57 / 70 30 20 30 30
NEW BRAUNFELS MUNI AIRPORT 36 30 45 37 61 / 60 30 10 30 20
BURNET MUNI AIRPORT 31 26 41 34 57 / 80 30 20 30 20
DEL RIO INTL AIRPORT 38 34 52 41 68 / 50 10 10 10 -
GEORGETOWN MUNI AIRPORT 33 27 42 34 56 / 70 40 20 30 30
HONDO MUNI AIRPORT 37 32 48 38 65 / 50 20 10 20 -
SAN MARCOS MUNI AIRPORT 35 30 44 37 59 / 70 30 10 30 20
LA GRANGE - FAYETTE REGIONAL 38 31 43 38 57 / 70 40 20 30 30
SAN ANTONIO INTL AIRPORT 38 31 45 38 62 / 60 30 10 20 10
STINSON MUNI AIRPORT 39 32 46 39 63 / 60 30 10 20 10
&&
.EWX WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY UNTIL 6 PM CST THIS EVENING FOR THE
FOLLOWING COUNTIES: BANDERA...BLANCO...BURNET...EDWARDS...
GILLESPIE...HAYS...KENDALL...KERR...LLANO...REAL...TRAVIS...VAL
VERDE...WILLIAMSON.
&&
$$
MESOSCALE/AVIATION...04
SYNOPTIC/GRIDS...17
PUBLIC SERVICE/DATA COLLECTION...00
FORECAST DISCUSSION FOR ROUTINE AFTERNOON FORECAST ISSUANCE
.SHORT TERM...TONIGHT AND TUESDAY
ISSUED AT 253 PM CST MON FEB 23 2015
THE LATEST RAP ANALYSIS AND SATELLITE/RADAR IMAGERY SHOW ARCTIC HIGH
PRESSURE SETTLING OVER THE MID-MISSISSIPPI VALLEY AND EXTENDING
ACROSS THE EASTERN GREAT LAKES. CLEAR SKIES REMAIN ACROSS MOST OF
THE REGION EARLY THIS AFTERNOON WITH WIND CHILLS WARMING INTO THE 5
TO 15 BELOW RANGE. CLOUDS ARE INCREASING OVER THE NORTHERN PLAINS
AHEAD OF A SHORTWAVE DIVING SOUTHEAST OVER LAKE WINNIPEG. LIGHT
SNOW AND BLOWING SNOW ARE OCCURRING AHEAD OF THIS SHORTWAVE BUT
THESE ARE OCCURRING MAINLY NORTH OF THE BORDER. SOME WIND GUSTS ARE
REACHING BETWEEN 30 AND 35 KNOTS. AS THIS SHORTWAVE AND A MORE
POTENT WAVE BEHIND IT MOVING INTO THE REGION...SNOWFALL POTENTIAL
AND IMPACTS ARE THE MAIN FORECAST CONCERNS.
TONIGHT...LEAD SHORTWAVE TROUGH OVER THE LAKE WINNIPEG REGION WILL
WEAKEN AS IT MOVES INTO THE REGION THIS EVENING. THE ARCTIC AIRMASS
AHEAD OF THIS WAVE IS VERY DRY...WHICH SHOULD KEEP THE AREA
PRECIP-FREE THROUGH THE EVENING. THEN AS A SECONDARY AND STRONGER
SHORTWAVE ARRIVES LATE TONIGHT...STRONG FORCING SHOULD PUSH AN AREA
OF LIGHT SNOW ACROSS THE REGION FROM NORTHWEST TO
SOUTHEAST...POSSIBLY MAKING IT INTO THE FOX VALLEY BY 12Z. ALTHOUGH
ACCUMULATIONS ARE EXPECTED TO REMAIN UNDER AN INCH...GUSTY SOUTHWEST
WINDS AHEAD OF THE SHORTWAVE WILL LEAD TO BLOWING AND DRIFTING SNOW
IN THE OPEN COUNTRY. THE CLOUDS AND WIND WILL PREVENT TEMPS FROM
FALLING MUCH TONIGHT...AND WILL GO WITH LOWS IN THE MIDDLE SINGLE
DIGITS ABOVE ZERO. WIND CHILLS WILL CONTINUE TO RANGE FROM 10 TO 20
BELOW THIS EVENING...THEN WARM AS TEMPERATURES RISE OVERNIGHT.
TUESDAY...THE LIGHT SNOW WILL CONTINUE TO SPREAD ACROSS THE FOX
VALLEY AND LAKESHORE AREAS EARLY IN THE MORNING BEFORE EXITING LATE
IN THE MORNING. MID-LEVEL MOISTURE PEELS OUT BEHIND THE SHORTWAVE
DURING THE AFTERNOON...BUT STEEPENING LOW LEVEL LAPSE RATES WITHIN A
BROKEN CLOUD DECK COULD YIELD SCATTERED FLURRIES. ADDITIONAL
ACCUMULATIONS COULD REACH UP TO A HALF INCH. GUSTY SOUTHWEST WINDS
IN THE MORNING WILL TURN TO THE WEST AND THEN NORTHWEST IN THE
AFTERNOON AND WILL PROMOTE BLOWING AND DRIFTING SNOW. WIND
TRAJECTORIES WILL BE PARALLEL TO DOOR COUNTY INITIALLY...BUT AS
WINDS VEER TO THE WEST AND THEN NORTHWEST...BLOWING AND DRIFTING
SNOW WILL INCREASINGLY BECOME A HAZARD TO THE WESTERN HALF OF THE
COUNTY EVEN AS WINDS SUBSIDE SOMEWHAT WITH THE APPROACH OF A SURFACE
TROUGH. SOME DISCUSSION WHETHER DOOR COUNTY WILL NEED A SNOW AND
BLOWING SNOW ADVISORY FOR TOMORROW. THINK WINDS WILL BE SOUTHWEST
THROUGH MOST OF THE SNOW FALL TOMORROW MORNING AND AM UNCERTAIN HOW
CONDITIONS WILL BE AFTER SEVERAL HOURS OF BLOWING/DRIFTING SNOW
PRIOR TO THIS. WILL ISSUE AN SPS HIGHLIGHTING THIS HAZARD.
TEMPERATURES WILL BE THE WARMEST IN SEVERAL DAYS...AND RANGE FROM
THE LOWER 20S TO LOWER 30S.
.LONG TERM...TUESDAY NIGHT THROUGH MONDAY
ISSUED AT 253 PM CST MON FEB 23 2015
A BIT OF A CHANGE IN THE UPPER FLOW PATTERN IS IN THE
OFFING...WITH THE WESTERN RIDGE DRIFTING WEST OVER THE PACIFIC AND
A CUT OFF LOW DEVELOPING OVER THE SOUTHWEST...SETTING UP SOMETHING
MORE AKIN TO A SPLIT FLOW PATTERN AS THE WEEK GROWS LATE. THE
NORTHERN STREAM STILL HOLDS SIGNIFICANT SWAY IN OUR AREA
UNFORTUNATELY...AND THE IMPACT ON SENSIBLE WEATHER IS UNLIKELY TO
BE SIGNIFICANT UNTIL LATE THIS WEEKEND OR EARLY NEXT WEEK.
SATELLITE IMAGERY INDICATES A PATCH OF SOMEWHAT OPEN WATERS ON
LAKE SUPERIOR ALONG A LAKE EFFECT FETCH FOR NORTH CENTRAL
WISCONSIN...AND BREEZY SOUTHWEST WINDS IN THE SHORT TERM SHOULD
KEEP THAT AREA FROM FREEZING OVER. THIS LEAVES POTENTIAL FOR
LINGERING LAKE EFFECT FLURRIES OR SNOW SHOWERS TUESDAY NIGHT
IN THE NORTH CENTRAL SNOW BELT...THOUGH ACCUMULATIONS SHOULD BE
SLIGHT TO NIL. GUSTY WINDS WILL BE DIMINISHING THROUGH THE EVENING
HOURS AS THE PRESSURE GRADIENT LOOSENS...BRINGING AN END TO
POTENTIAL FOR BLOWING SNOW.
ANOTHER BEEFY HIGH WILL FOLLOW IN TO GIVE US ANOTHER PLUNGE IN
TEMPERATURES...BUT BEFORE THAT A SHORTWAVE WILL SHOOT THROUGH
THE UPPER TROUGH. THE GEM STUBBORNLY BRINGS FLURRIES OR EXTREMELY
LIGHT ACCUMULATIONS TO PORTIONS OF CENTRAL AND EAST CENTRAL
WISCONSIN. THE REST OF THE GUIDANCE SHUNTS EVERYTHING WELL SOUTH
OF THE AREA...AND THE FORECAST JOINS THAT CAMP IN KEEPING THINGS
DRY HERE.
THE MAIN STORY FOR THE SECOND HALF OF THE WORK WEEK...AGAIN...WILL
BE SIGNIFICANTLY BELOW NORMAL TEMPS. THE COLD AIR REACHES ITS
NADIR WEDNESDAY AFTERNOON INTO THURSDAY. HIGHS IN THE SINGLE
DIGITS TO LOW/MID TEENS ARE EXPECTED WITH LOWS BELOW ZERO. WIND
CHILL ADVISORIES MAY RETURN FOR ANOTHER SEQUEL...BUT THIS COLD
PUSH DOES NOT LOOK TO MATCH PREVIOUS ITERATIONS...SO THERE IS LESS
CONFIDENCE IN THAT AT THIS TIME. THE ARCTIC AIR MASS BEGINS TO
MODERATE ON FRIDAY AND ESPECIALLY THIS WEEKEND...BUT TEMPERATURES
STILL LOOK TO REMAIN BELOW NORMAL.
HEADING INTO THE WEEKEND...AS A TROUGH DIGS OVER THE WEST COAST
AND THE FLOW ALOFT BECOMES SOUTHWESTERLY. THIS FLOW WILL PUSH IN A
SLUG OF MOISTURE FROM THE SOUTHERN PLAINS FOR THE SECOND HALF OF
THE WEEKEND. MODELS ARE IN AGREEMENT SHOWING THE MOISTURE AND
PUSH OF WARMER AIR. HOWEVER...THERE IS SPREAD IN HOW FAR NORTH
THIS AIR GETS...WITH SIGNIFICANT IMPACTS ON SNOW POTENTIAL. THE
CANADIAN HOLDS COLD AIR OVER THE GREAT LAKES AND SENDS YET ANOTHER
WINTER STORM THROUGH THE MID-SOUTH AND FAR AWAY FROM OUR AREA. THE
GFS AND ECMWF ARE MORE READY TO BRING A MORE SIGNIFICANT SYSTEM
TOWARDS THE GREAT LAKES. AT THIS TIME IT AGAIN APPEARS THAT THE
HIGHEST SNOWFALL TOTALS WILL MISS THE AREA. HOWEVER...IT IS
POSSIBLE...GIVENT THE CURRENT GUIDANCE ENVELOPE...FOR ENOUGH
SNOWFALL TO MEET ADVISORY CRITERIA IN CENTRAL AND EAST CENTRAL
WISCONSIN. ULTIMATELY...THE MODEL SOLUTIONS ARE RELATIVELY FRAGILE
THIS FAR OUT...AND THE BEST ADVICE IS TO FOLLOW UPDATED FORECASTS
AS THE WEEK CONTINUES.
&&
.AVIATION...FOR 18Z TAF ISSUANCE
ISSUED AT 1134 AM CST MON FEB 23 2015
VFR CLEAR EXPECTED THROUGH THE EVENING AS CIRRUS SPREADS
ACROSS THE REGION AHEAD OF THE NEXT CLIPPER. SOUTHWEST WINDS WILL
INCREASE THROUGH THE AFTERNOON AND BECOME STRONG ENOUGH TO PRODUCE
BLOWING AND DRIFTING SNOW THIS EVENING THROUGH TUESDAY MORNING.
LIGHT SNOW WILL ARRIVE FROM NORTHWEST TO SOUTHEAST LATE TONIGHT AND
CONTINUE THROUGH MIDDAY TUESDAY BEFORE DIMINISHING/EXITING. THOUGH
THE SNOW WILL LIKELY DROP VSBYS TO IFR FOR A TIME...SNOW AMOUNTS
SHOULD BE AROUND AN INCH OR LESS IN MOST PLACES. LOW LEVEL WIND
SHEAR POSSIBLE TONIGHT WITH GUSTY SOUTHWEST SURFACE WINDS AND
SOUTHWEST WINDS OF 40 KNOTS AT 1200 FT AGL.
FIELD CREWS MAY BE NEEDED TO CLEAR SNOW DRIFTS FROM
RUNWAYS, TAXIWAYS AND RAMPS TONIGHT.
&&
.GRB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM.....MPC
LONG TERM......LUCHS
AVIATION.......MPC