Forecast Discussions mentioning any of
"HRRR" "RAP" "RR" "RUC13" "RUC" received at GSD on 02/21/15
AREA FORECAST DISCUSSION
NWS LITTLE ROCK AR
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 31 44 29 34 / 100 100 20 20
CAMDEN AR 48 65 37 43 / 80 90 40 30
HARRISON AR 31 43 25 28 / 100 90 10 20
HOT SPRINGS AR 38 55 34 40 / 90 90 20 20
LITTLE ROCK AR 37 54 33 38 / 90 100 30 20
MONTICELLO AR 45 65 36 41 / 90 90 50 20
MOUNT IDA AR 38 53 34 40 / 90 90 20 20
MOUNTAIN HOME AR 29 44 25 30 / 100 90 20 20
NEWPORT AR 32 45 29 34 / 100 100 30 20
PINE BLUFF AR 41 61 34 39 / 90 100 40 20
RUSSELLVILLE AR 34 51 32 38 / 100 90 20 20
SEARCY AR 33 46 31 36 / 100 100 30 20
STUTTGART AR 37 55 33 37 / 90 100 40 20
&&
.LZK WATCHES/WARNINGS/ADVISORIES...
WINTER STORM WARNING UNTIL MIDNIGHT CST TONIGHT FOR BAXTER-
CLEBURNE-FULTON-INDEPENDENCE-IZARD-JACKSON-SHARP-STONE.
WINTER WEATHER ADVISORY UNTIL MIDNIGHT CST TONIGHT FOR BOONE-
FAULKNER-MARION-NEWTON-SEARCY-VAN BUREN-WHITE-WOODRUFF.
&&
$$
65
AREA FORECAST DISCUSSION
NWS ALBANY NY
1235 AM EST THU FEB 19 2015
.SYNOPSIS...
A LOW PRESSURE SYSTEM WILL MOVE ACROSS THE REGION TONIGHT AND
THURSDAY ACCOMPANIED BY SNOW SHOWERS AND POSSIBLE EVEN A SNOW
SQUALL. ANOTHER SHOT OF VERY COLD ARCTIC AIR WILL INVADE THE
REGION BY THURSDAY NIGHT LASTING INTO FRIDAY WITH WIND DRIVING
WIND CHILLS WELL BELOW ZERO ONCE AGAIN.
&&
.NEAR TERM /UNTIL 6 AM THIS MORNING/...
AS OF 1235 AM EST...AN ARCTIC OCCLUDED FRONT IS IN THE PROCESS OF
SLOWLY MOVING ACROSS EASTERN UPSTATE NY. TEMPS AHEAD OF THIS
BOUNDARY CONTINUE TO BE IN THE MID TEENS TO LOWER 20S...WHILE
TEMPS OVER WESTERN/CENTRAL NY HAVE FALLEN INTO THE SINGLE DIGITS
AND LOWER TEENS. THERE HAD BEEN AN ORGANIZED BAND OF HEAVY SNOW
SHOWERS/SQUALLS AHEAD OF THE SFC BOUNDARY OVER CNY...BUT THIS HAS
WEAKENED OVER THE LAST FEW HOURS. THE 04Z 3KM HRRR SUGGESTS THAT
THIS WEAKENING TREND WILL CONTINUE...AND ONLY SOME LINGERING LIGHT SNOW
SHOWERS OR FLURRIES WILL ACCOMPANY THIS BOUNDARY AS IT CROSSES OUR
AREA FOR THE REMAINDER OF THE OVERNIGHT...WITH THE BEST CHANCE
ACROSS CENTRAL AND NORTHERN AREAS. BASED ON THIS...ADDITIONAL
SNOW ACCUMULATION OVERNIGHT LOOKS ONLY TO BE AN INCH OR LESS FOR
MOST SPOTS...AS LIMITED MOISTURE WILL PREVENT MUCH SNOWFALL FROM
OCCURRING.
ONCE THE BOUNDARY CROSSES THE AREA...TEMPS WILL SLOWLY START TO
FALL AND WESTERLY WINDS WILL START TO INCREASE TO AROUND 10 KTS.
IN MOST PLACES...THIS WON/T OCCUR UNTIL NEARLY DAYBREAK...WITH THE
COLDEST TEMPS IN OUR AREA BY DAYBREAK FOR WESTERN PARTS OF THE
AREA.
&&
.SHORT TERM /6 AM THIS MORNING THROUGH SATURDAY/...
AS THE OCCLUDED FRONT WORKS INTO OUR REGION ON THURSDAY...THERE
WILL BE A SECONDARY LOW DEVELOPING ALONG THE TRIPLE POINT OFF THE
LONG ISLAND COAST. THIS SECONDARY COASTAL LOW WILL MAINLY MISS OUR
AREA...BUT THE UPPER AIR LOW PORTION OF THE STORM WILL MOVE
THROUGH ON THURSDAY IN CONJUNCTION WITH THE ARCTIC FRONT. THE
COMBINATION OF THE THESE FEATURES WILL PRODUCE ADDITIONAL
SCATTERED SNOW SHOWERS...AND POSSIBLY SOME LOCALIZED SNOW SQUALLS
SHOULD WE GET ENOUGH SNOW...WHICH WOULD PRODUCE GREATER LOW LEVEL
INSTABILITY. CURRENT MODEL DATA DOES NOT INDICATE MUCH SURFACE
BASED CAPE SO FOR NOW...WILL NOT MENTION ANY (+SW) IN THE GRIDS
BUT THERE IS A SLIGHT POSSIBILITY THAT WE COULD SEE SOME LOW
LOCALIZED SNOW SQUALLS. ADDITIONAL SNOWFALL WILL GENERALLY BE AN
INCH OR LESS...BUT UNDERNEATH ANY SNOW SQUALL...COULD REACH UP TO
2 INCHES.
TEMPERATURES ON THURSDAY WILL BE HARD PRESS TO RISE MUCH AT ALL.
THEY WILL TOP OUT IN THE TEENS ACROSS MOST AREAS FROM THE HUDSON
EASTWARD...SINGLE NUMBERS HIGHER TERRAIN. HOWEVER...THEY MIGHT
ACTUALLY BEGIN TO FALL DURING THE AFTERNOON...SLOWLY...AND BY DARK
MOST AREAS WILL DOWN INTO THE SINGLE NUMBERS (SINGLE NUMBERS BELOW
ZERO ACROSS THE ADIRONDACKS). THE WIND WILL PICK UP BY
AFTERNOON...WITH GUSTS OUT OF THE NORTHWEST FROM 25-35 MPH.
THURSDAY NIGHT WILL BE BITTERLY COLD IN WHAT SHOULD BE OUR 13TH
NIGHT BELOW ZERO IN ALBANY...AND WELL BELOW ZERO ACROSS OUR ELEVATED
ZONES (ESPECIALLY THE ADIRONDACKS). THE COMBINATION OF A PERSISTENT
10-15 MPH NOCTURNAL WIND WILL DRIVE TEMPERATURES INTO THE WIND
ADVISORY AREAS (-15 TO -25) AND POSSIBLY LOWER THAN 30 BELOW ACROSS
THE ADIRONDACKS. FOR NOW...WE DECIDED AGAINST ANY WIND CHILL WATCHES
(CONFIDENCE NOT QUITE THERE YET) BUT WILL CONTINUE TO MENTION IN OUR
HAZARDOUS WEATHER OUTLOOK.
SCATTERED SNOW SHOWERS WILL LIKELY PERSIST IN THE UPSLOPE AREAS OF
THE ADIRONDACKS AND SOUTHERN GREENS THROUGH THE EVENING HOURS. THEN
AS DRIER AIR WORKS IN AT ALL LEVELS...THESE SHOULD DISSIPATE
OVERNIGHT THURSDAY. ADDITIONAL SNOWFALL IN THESE AREAS WILL BE A
COATING TO TWO INCHES.
FRIDAY SHOULD BE A DRY MAINLY SUNNY DAY BUT IT WILL REMAIN
BITTERLY COLD WITH A STIFF BREEZE FROM THE NORTHWEST. HIGHS WILL
ONLY BE IN THE SINGLE NUMBERS ACROSS THE HIGHER TERRAIN...10-15
MOST VALLEY AREAS...EXCEPT 15-20 MID HUDSON VALLEY AND LOWER
LITCHFIELD COUNTY.
BY FRIDAY NIGHT HIGH PRESSURE WILL CREST OVER THE REGION. AT THIS
POINT...THIS LOOKS LIKE ONE OF THE COLDEST NIGHTS OF THE WHOLE
WINTER AS THE WIND WILL RELAX AND THE SKY SHOULD REMAIN MAINLY
CLEAR...AT LEAST THROUGH THE EVENING HOURS. GIVEN THESE TWO
CONSIDERATIONS...WE LEANED WITH THE COLDER GUIDANCE (MAV) AND IN
SOME CASES WENT EVEN LOWER (ESPECIALLY PLACES LIKE KGFL). WE LOOK
FOR LOWS 5 TO 10 BELOW ZERO IN THE HUDSON VALLEY FROM ALBANY SOUTH
TO POUGHKEEPSIE. FURTHER NORTH...LOOK FOR LOWS 10 TO 15 BELOW ACROSS
MOST OF THE MOHAWK VALLEY...ADIRONDACKS...LAKE GEORGE SARATOGA
REGION AND SOUTHERN VERMONT. THE ONLY CONSOLATION IS THAT THERE
SHOULD BE NO WIND...SO ADDED WIND CHILL TO OTHERWISE EXTREMELY
FRIGID NIGHT.
SATURDAY...HIGH PRESSURE WILL BE OFFSHORE. ANOTHER LOW WILL PRESSURE
WILL BE APPROACHING. INSTEAD OF CLIPPER...THIS WILL BE SOUTHERN JET
STREAM LOW...WHICH LOOKS TO TRACK INTO THE OHIO VALLEY BY LATE
SATURDAY. THE DAY WILL START OFF DRY SATURDAY...WITH INCREASING
CLOUDS. THERE IS A CHANCE OF LIGHT SNOW BY AFTERNOON AS OVERRUNNING
COMMENCES. A SOUTHERLY BREEZE SHOULD BUMP TEMPERATURES UP TO THE
TEENS NORTH...LOWER 20S SOUTH...BUT GENERALLY WENT ON THE LOW SIDE
OF GUIDANCE.
&&
.LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/...
THE LONG TERM PERIOD WILL BE DOMINATED BY A STORM SYSTEM THAT WILL
IMPACT THE ENTIRE REGION TO END THE WEEKEND...AND CONTINUED BELOW
NORMAL TEMPERATURES.
AT THE START OF THE LONG TERM PERIOD...LONG RANGE GUIDANCE CONTINUES
TO BE IN AGREEMENT WITH THE DEVELOPMENT OF A SOUTHERN STREAM SYSTEM
ACROSS THE OHIO VALLEY...WITH A CONSENSUS TRACK WEST OF THE FORECAST
AREA ACROSS WESTERN NEW YORK. THE UPPER-LEVEL PATTERN CONTINUES TO
FAVOR A MORE PROGRESSIVE SOLUTION...ALTHOUGH NORTHERN STREAM ENERGY
IS EXPECTED TO INTERACT WITH THE SYSTEM SUNDAY AS ANOTHER POTENT
PIECE OF THE HUDSON BAY VORTEX DIVES SOUTHEASTWARD.
THE LEVEL OF NORTHERN STREAM INTERACTION WILL ULTIMATELY DETERMINE
HOW FAR WEST THE SURFACE CYCLONE TRACKS...WITH THE 12Z ECMWF
TRACKING IT ACROSS THE SAINT LAWRENCE RIVER VALLEY AND THE 12Z GFS
SLIGHTLY FURTHER EAST. MUCH OF THE GEFS MEMBERS INDICATE A WESTWARD
TRACK...BUT MUCH MORE PROGRESSIVE THAN THE ECMWF SOLUTION AND AGAIN
ACROSS WESTERN NEW YORK.
REGARDLESS...LONG RANGE GUIDANCE CONTINUES TO COME INTO BETTER
AGREEMENT FOR ANOTHER SIGNIFICANT STORM SYSTEM TO IMPACT THE REGION
LATE SATURDAY NIGHT INTO SUNDAY NIGHT. INITIALLY SATURDAY NIGHT...IT
LOOKS LIKE THE HEAVIER PRECIPITATION SHIELD WILL HOLD OFF UNTIL
AFTER MIDNIGHT WHEN WARM AIR ADVECTION AND ISENTROPIC LIFT ENHANCE
DYNAMIC LIFT AND ALLOW FOR OVERRUNNING PRECIPITATION TO OVERSPREAD
THE REGION.
TEMPERATURES INITIALLY LOOK COLD ENOUGH FOR SNOW...WITH THE
POTENTIAL FOR LIGHT TO MODERATE SNOWFALL ACCUMULATIONS BY LATE
SUNDAY MORNING ACROSS MOST OF THE FORECAST AREA. THE BIG QUESTION
THEN BECOMES HOW MUCH LOW-LEVEL WARM AIR MOVES INTO THE REGION
DURING THE DAY SUNDAY...AS 12Z GEFS PLUMES SUGGEST A SNOW TO RAIN
TRANSITION FOR AREAS SOUTH AND EAST OF THE CAPITAL REGION...WITH A
FEW MEMBERS INDICATING THE POTENTIAL FOR A WINTRY MIX.
HOWEVER...THE LOW-LEVEL WARM INTRUSION MAY BE INHIBITED...AS A
FAIRLY STRONG 1028 HPA AREA OF HIGH PRESSURE ACROSS QUEBEC AND
STRONG VERTICAL ASCENT IN THE RIGHT ENTRANCE REGION OF THE POLAR JET
MAY ENHANCE THE LOW-LEVEL AGEOSTROPHIC FLOW...ALLOWING COLD AIR NEAR
THE SURFACE TO REMAIN TRAPPED FOR A POSSIBLE PROLONGED PERIOD OF
WINTRY MIX WITH MAINLY SNOW ACROSS FAR NORTHERN AREAS. AN ALL-RAIN
SCENARIO APPEARS UNLIKELY AT THIS TIME...ALTHOUGH NOT OUT OF THE
QUESTION...ESPECIALLY IF THE SOUTHERN STREAM BRANCH DOMINATES AND
HELPS THRUST STRONG WARM AIR ADVECTION INTO THE REGION. SINCE THE
STORM IS STILL QUITE A WAYS OUT...WILL JUST MENTION RAIN/SNOW FOR
THE CAPITAL REGION AND POINTS SOUTH AND EAST FOR LATE SUNDAY MORNING
INTO THE AFTERNOON/EVENING HOURS.
AT THIS TIME...THE GREATEST THREAT FOR PRECIPITATION LOOKS TO BE
LATE SATURDAY NIGHT AND THROUGH MOST OF THE DAY SUNDAY...WITH
POSSIBLE AREAS OF ENHANCED PRECIPITATION SUNDAY MORNING AND
AFTERNOON DEPENDING ON THE STRENGTH OF THE LOW-LEVEL JET SEGMENT.
WILL CONTINUE TO MENTION THIS STORM SYSTEM IN THE HAZARDOUS WEATHER
OUTLOOK WITH THE THREAT FOR SIGNIFICANT ACCUMULATING PRECIPITATION.
THE STORM SYSTEM LOOKS TO EXIT NORTHEAST OF THE REGION SUNDAY
NIGHT...WITH COLDER AIR BEING USHERED IN BEHIND IT FOR SCATTERED
SNOW SHOWERS ENDING FROM WEST TO EAST BY MONDAY MORNING. BEHIND THIS
SYSTEM...HIGH PRESSURE WILL BUILD ACROSS THE REGION EARLY NEXT WEEK
BEFORE A CLIPPER-TYPE SYSTEM...LARGELY MOISTURE-STARVED...IMPACTS
THE REGION FOR THE MIDWEEK PERIOD.
LOW TEMPERATURES SATURDAY NIGHT LOOK TO BE COLDEST DURING THE
EVENING HOURS...UPPER TEENS TO LOW 20S...AND THEN GRADUALLY WARM
THROUGH THE NIGHT AS WARM AIR ADVECTION SPREADS ACROSS THE REGION.
HIGH TEMPERATURES SUNDAY WILL BE THE WARMEST IN QUITE SOME
TIME...WITH HIGHS RANGING FROM THE UPPER 20S TO UPPER 30S. DEPENDING
ON HOW MUCH WARM AIR INTRUDES INTO THE REGION...LOW 40S CANNOT BE
RULED OUT ACROSS THE MID-HUDSON VALLEY. LOW TEMPERATURES SUNDAY
NIGHT WILL RANGE FROM NEAR ZERO ACROSS THE SOUTHERN ADIRONDACKS TO
LOW TEENS ACROSS VALLEY AREAS.
MUCH COLDER AIR WILL ONCE AGAIN BECOME REESTABLISHED ACROSS THE
REGION EARLY NEXT WEEK...WITH HIGH TEMPERATURES MONDAY AND TUESDAY
RANGING FROM THE LOW TEENS TO LOW 20S. LOW TEMPERATURES MONDAY NIGHT
WILL BE BELOW ZERO ACROSS MUCH OF THE REGION AS HIGH PRESSURE CRESTS
OVER THE AREA WITH A DEEP SNOWPACK STILL IN PLACE. DESPITE THESE
FRIGID TEMPERATURES...LIGHT WINDS WILL LIMIT WIND CHILLS. LOWS
TUESDAY NIGHT WILL RANGE FROM 5 BELOW ZERO TO 5 ABOVE.
&&
.AVIATION /06Z THURSDAY THROUGH MONDAY/...
ONE AREA OF SNOW HAS EXITED...WHILE A SCATTERED LINE OF SNOW SHOWERS
TRACKS THROUGH THE MOHAWK VALLEY AND EASTERN CATSKILLS. THE LINE OF
SNOW SHOWERS WILL BRING A BRIEF LOWERING OF VISIBILITIES AND
CEILINGS TO KALB...KGFL AND KPSF BETWEEN 06Z AND 08Z...DEPENDING ON
HOW THE LINE HOLDS TOGETHER. THERE HAS BEEN EVIDENCE OF WEAKENING
AS IT TRACKS EAST BUT SUGGESTING A BRIEF LOWERING OF VISIBILITIES
AND CEILINGS FOR LESS THAN AN HOUR WITHIN THAT TIME SPAN.
BEHIND THE LINE OF SNOW SHOWERS...THERE ARE AREAS OF VERY LIGHT SNOW
THAT ARE SLOWLY EXPANDING EAST...BUT SEEMS TO BE SLOWING ITS
EXPANSION AROUND THE EASTERN CATSKILLS AND SCHOHARIE VALLEY. WEST
TO NORTHWEST WINDS AND COLD ADVECTION CROSSING THE LAKES COULD HELP
SOME LIGHT SNOW EXPAND EAST TOWARD DAYBREAK...AND INDICATING
INTERMITTENT MVFR CEILINGS AND VISIBILITIES BETWEEN ABOUT 09Z AND
12Z. AFTERWARD COVERAGE SHOULD DECREASE AND THEN VCSH AT ALL SITES
THROUGH ABOUT 14Z-16Z. CONSISTENT VFR CONDITIONS SHOULD OCCUR THIS
AFTERNOON AND EVENING.
WIND WILL BE LIGHT/VARIABLE THROUGH THE EARLY MORNING HOURS...
TRENDING TO WEST AND NORTHWEST AT LESS THAN 10 KT. WEST TO
NORTHWEST WINDS WILL INCREASE IN SPEED WITH THE PASSAGE OF THE
SYSTEM. AS THE SYSTEM DEEPENS THROUGH THE DAY WINDS WILL INCREASE IN
SPEED AND BECOME GUSTY WITH 15 TO 20 KNOTS SUSTAINED EXPECTED WITH
GUSTS UP TO 30 KNOTS. THE STRONGEST WINDS ARE EXPECTED AT KALB AS
THE FLOW IS FUNNELED DOWN THE MOHAWK VALLEY.
OUTLOOK...
THU NIGHT: LOW OPERATIONAL IMPACT. SLIGHT CHC SHSN.
FRI-FRI NIGHT: NO OPERATIONAL IMPACT. NO SIG WX.
SAT: MODERATE OPERATIONAL IMPACT. CHC SN.
SAT NIGHT: HIGH OPERATIONAL IMPACT. SN LIKELY.
SUN: HIGH OPERATIONAL IMPACT. SN LIKELY WITH RN POSSIBLE AT
KPOU/KALB.
SUN NIGHT: MODERATE OPERATIONAL IMPACT. CHC SHSN
MON: NO OPERATIONAL IMPACT. NO SIG WX.
&&
.HYDROLOGY...
ICE WILL CONTINUE TO THICKEN ON AREA RIVERS...STREAMS...LAKES...AND
PONDS...AS CONTINUED BELOW NORMAL TEMPERATURES REMAIN IN PLACE
THROUGH THE REMAINDER OF THE WEEK. TEMPERATURES LOOK TO STAY BELOW
FREEZING THROUGH SATURDAY.
ANY PRECIPITATION ...ALL IN THE FORM OF SNOW...WILL BE FAIRLY LIGHT OVER THE
NEXT FEW DAYS. SNOW SHOWERS ARE LIKELY IN MOST PLACES TONIGHT AND
POSSIBLE AGAIN TOMORROW. HOWEVER...ANY SNOW WILL HAVE LITTLE TO NO
IMMEDIATE IMPACT ON AREA WATERWAYS. SOME GAGES WILL EXPERIENCE ICE
EFFECTS...AND SOME ERRONEOUS DATA MAY BE SEEN FROM TIME TO TIME.
A STORM SYSTEM WILL IMPACT THE REGION OVER THE WEEKEND WITH SOME
ADDITIONAL PRECIPITATION...MAINLY ON SUNDAY. IT IS STILL UNCLEAR
IN WHAT FORM THIS PRECIPITATION WILL BE RAIN...SNOW...OR MIXED
PRECIPITATION AND EXACT AMOUNTS ARE STILL FAR FROM CERTAIN. WE
WILL NEED TO MONITOR THE POTENTIAL FOR HOW THIS STORM MAY IMPACT
THE HYDROLOGIC AREA.
FOR DETAILS ON SPECIFIC AREA RIVERS AND LAKES...INCLUDING
OBSERVED AND FORECAST RIVER STAGES AND LAKE ELEVATIONS...PLEASE
VISIT THE ADVANCED HYDROLOGIC PREDICTION SERVICE /AHPS/ GRAPHS ON
OUR WEBSITE.
&&
.ALY WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
NY...NONE.
MA...NONE.
VT...NONE.
&&
$$
SYNOPSIS...IAA/FRUGIS/HWJIV
NEAR TERM...FRUGIS
SHORT TERM...HWJIV
LONG TERM...IRL
AVIATION...NAS
HYDROLOGY...FRUGIS
AREA FORECAST DISCUSSION
NWS JACKSONVILLE FL
909 PM EST FRI FEB 20 2015
.UPDATE...STRONG HIGH PRES RIDGE AT 1035 MB LOCATED OVER ERN
NORTH CAROLINA CONTINUES TO SUPPORT LIGHT NE TO E FLOW OVER THE
LOCAL AREA. LIGHT WINDS STILL ONGOING OVER LAND WITH SPEEDS AROUND
5 TO 10 MPH. MID AND HIGH LEVEL CLOUDS WILL CONTINUE TO GRADUALLY
SPREAD ESEWD THROUGH OUR AREA THROUGH SAT MORNING...AS THE SFC
HIGH NORTH OF THE AREA MOVES EWD.
TEMPERATURES AND DEWPOINTS OVER THE LOCAL AREA REFLECT A GRADUAL
AIRMASS MODIFICATION COMPARED TO YESTERDAY...WITH RUC13 SHOWING
WARM ADVECTION OCCURRING OVER THE SRN ZONES ESPECIALLY. GIVEN THIS
AND THE SLOW FALL IN TEMPS AND HIGHER DEWPOINTS THAN FCST...WILL
TRIM OFF A COUPLE COUNTIES TO THE CURRENT FREEZE WARNING FOR NE
FL. WILL REPLACE WITH FROST ADVY AS TEMPS DROP MAINLY INTO THE MID
30S FOR PUTNAM AND MARION COUNTIES. REST OF THE FREEZE WARNING
AREA WILL GET UP TO 2 TO 3 HOURS OF FREEZE. WEAK ONSHORE FLOW AND
MODIFICATION WILL RESULT IN AN ACTUAL INCREASE IN TEMPS TOWARD THE
PREDAWN HOURS. SOME STRATOCU EXPECTED TO ADVECT INTO MARINE ZONES
BUT GENERALLY STAYING OFFSHORE UNTIL AFTER SUNRISE SATURDAY...WITH
ISOLD LIGHT SHOWER POSSIBLE BEYOND 20 NM FROM SHORE.
&&
.AVIATION...VFR. MID AND HIGH CLOUDS EXPECTED TONIGHT. SCT CUMULUS
EXPECTED SATURDAY. LIGHT TO CALM WINDS TONIGHT BECOME SELY 5 TO
10 KNOTS ON SATURDAY.
&&
.MARINE...NE TO E WINDS WERE AROUND 10 KT AND SEAS ESTIMATED
AROUND 2-3 FT AT 9 PM. A FEW MINOR ADJUSTMENTS FOR WINDS AND SEAS
BUT LITTLE OVERALL CHANGE EXPECTED FOR THE CWF UPDATE.
&&
.PRELIMINARY POINT TEMPS/POPS...
AMG 31 67 48 72 / 0 0 0 30
SSI 35 61 51 70 / 0 0 10 10
JAX 32 68 50 77 / 0 0 10 10
SGJ 39 66 54 73 / 0 0 10 10
GNV 31 71 50 79 / 0 0 0 10
OCF 33 73 52 80 / 0 10 10 10
&&
.JAX WATCHES/WARNINGS/ADVISORIES...
FL...FROST ADVISORY UNTIL 8 AM EST SATURDAY FOR MARION-PUTNAM.
FREEZE WARNING UNTIL 8 AM EST SATURDAY FOR ALACHUA-BAKER-
BRADFORD-CLAY-COLUMBIA-GILCHRIST-HAMILTON-INLAND DUVAL-
INLAND NASSAU-SUWANNEE-UNION.
GA...NONE.
AM...NONE.
&&
$$
SHASHY/PETERSON/GUILLET
AREA FORECAST DISCUSSION
NWS COLUMBIA SC
900 PM EST FRI FEB 20 2015
.SYNOPSIS...
HIGH PRESSURE WILL MOVE OFF THE CAROLINA COAST TONIGHT. A WEAK
WARM FRONT WILL DEVELOP AND REMAIN NEAR THE FORECAST AREA THROUGH
SATURDAY. A COLD FRONT APPROACHING FROM THE NORTHWEST WILL MOVE
THROUGH THE FORECAST AREA SUNDAY AND SUNDAY NIGHT.
&&
.NEAR TERM /UNTIL 6 AM SATURDAY MORNING/...
MID AND HIGH LEVEL CLOUDS CONTINUE TO STREAM IN FROM THE WEST.
REGIONAL COMPOSITE RADAR AND SURFACE OBSERVATIONS REPORTING LIGHT
SNOW/SLEET OVER PORTIONS OF NORTHERN GA. ALTHOUGH AIRMASS IS STILL
FAIRLY DRY OVER OUR AREA...THIS LIGHT PRECIPITATION IS HELPING TO
MOISTEN THE ATMOSPHERE. HRRR SHOWS THIS PRECIPITATION DRYING OUT
BEFORE CROSSING THE SAVANNAH RIVER...BUT GIVEN LATEST
OBSERVATIONS...WILL MENTION SLIGHT CHANCE OF LIGHT WINTRY
PRECIPITATION OVER THE CSRA UNTIL SHORTLY AFTER MIDNIGHT. NO
ACCUMULATION IS EXPECTED. PREVIOUS DISCUSSION: HIGH PRESSURE WILL
BE SHIFTING OFF THE CAROLINA COAST WITH A DEVELOPING WARM
ADVECTION PATTERN. THE MODELS INDICATE A WEAK WARM FRONT
DEVELOPING JUST SOUTH OF THE FORECAST AREA. IT IS INITIALLY VERY
DRY AND THERE SHOULD NOT BE ENOUGH OF A MOISTURE INCREASE FOR
PRECIPITATION. ALL OF THE GFS AND NAM MOS PLUS THE SREF GUIDANCE
INDICATE CONTINUED DRY CONDITIONS. IT WILL BE ANOTHER COLD
NIGHT...BUT NOT AS COLD AS LAST NIGHT BECAUSE OF WARM
ADVECTION...MOISTURE INCREASE...AND AIR MASS MODIFICATION. THE
TEMPERATURE GUIDANCE WAS CLOSE.
&&
.SHORT TERM /6 AM SATURDAY MORNING THROUGH SUNDAY/...
THE WARM ADVECTION PATTERN ASSOCIATED WITH THE OFFSHORE HIGH WITH
A WEAK WARM FRONT SOUTH OF THE AREA SHOULD RESULT IN CONSIDERABLE
CLOUDINESS SATURDAY. PRECIPITATION IS POSSIBLE BUT THE CHANCE
APPEARS LOW. THE MODELS HAVE CONTINUED TO KEEP THE BULK OF DEEPER
MOISTURE NORTHWEST OF THE FORECAST AREA. THE NAM AND GFS MOS HAVE
TRENDED LOWER WITH POPS WITH LESS THAN 10 PERCENT IN THE SOUTH TO
20 TO 40 PERCENT IN THE NORTH. THE NORTH PART WILL BE CLOSER TO
DEEPER MOISTURE AND LIFT ASSOCIATED WITH A WEAK MID-LEVEL
SHORTWAVE TROUGH. HAVE MAINTAINED JUST SLIGHT CHANCE POPS BASED ON
THE INITIAL DRYNESS AND MODEL TRENDS. SOMEWHAT DEEPER MOISTURE IN
THE NORTHWEST PART INDICATES A POSSIBLE EARLIER START TIME. IF
THIS WERE TO OCCUR FORECAST SOUNDINGS SUPPORT SLEET AND FREEZING
RAIN. WE HAVE KEEP THE SLIGHT CHANCE OF FROZEN PRECIPITATION IN
THE NORTH SECTION. ANY PRECIPITATION SHOULD BE LIGHT BECAUSE OF
SHALLOW MOISTURE. THE MODELS ARE IN GOOD AGREEMENT INDICATING ALL-
LIQUID PRECIPITATION BY AFTERNOON.
THE NAM AND GFS CONTINUE TO SHOW LIMITED MOISTURE SATURDAY NIGHT
WITH WEAK ISENTROPIC LIFT. WE HAVE FORECASTED A SMALL POP. THE
RAIN CHANCE SHOULD INCREASE SUNDAY ASSOCIATED WITH CONVERGENCE
ALONG A COLD FRONT. THE GFS AND NAM MOS POPS HAVE TRENDED HIGHER.
EXPECT A BRIEF WARM UP SUNDAY JUST AHEAD OF THE FRONT...ALTHOUGH
THE SURFACE MAY REMAIN DECOUPLED IF THE WEAK WARM FRONT LINGERS IN
THE AREA. WE USED THE COOLER HIGH TEMPERATURE GUIDANCE.
&&
.LONG TERM /SUNDAY NIGHT THROUGH FRIDAY/...
THE GFS AND ECMWF MOS KEEP TEMPERATURES BELOW NORMAL DURING THE
MEDIUM-RANGE PERIOD. THE GFS AND ECMWF SHOW THE FRONT LINGERING
NOT FAR TO THE SOUTHEAST DURING MUCH OF THE PERIOD. THERE HAS
BEEN LITTLE CONSISTENCY WITH THE PLACEMENT OF MOISTURE AND
POSSIBLE WAVE DEVELOPMENT ALONG THIS FRONT. THE GFS ENSEMBLE
GUIDANCE HAS A HIGH SPREAD THROUGH THE PERIOD. THERE IS SOME
POTENTIAL FOR WINTRY WEATHER BUT HIGH UNCERTAINTY WITH THE TIMING.
&&
.AVIATION /02Z SATURDAY THROUGH WEDNESDAY/...
VFR CONDITIONS EXPECTED THROUGH TONIGHT.
DRY HIGH PRESSURE IN PLACE OVER THE REGION WILL SHIFT OFFSHORE
TONIGHT...GIVING WAY TO LOW PRESSURE MOVING NORTHEASTWARD FROM THE
LOWER MISSISSIPPI VALLEY TO THE OHIO VALLEY ON SATURDAY. MID LEVEL
CLOUDS ASSOCIATED WITH WARM ADVECTION WILL OVERSPREAD THE
TERMINALS THIS EVENING WITH CEILINGS DROPPING LATER TONIGHT
THROUGH THE PREDAWN HOURS AS MOISTURE INCREASES ACROSS THE REGION.
NAM GUIDANCE IS SUGGESTING TO MVFR CEILINGS WILL DEVELOP SOMETIME
AFTER 12Z WHILE THE GFS/RAP/HRRR ARE LESS CERTAIN IN RESTRICTIONS
OCCURRING AS THEY SHIFT THEM MORE THROUGH THE UPSTATE...WEST OF
THE TERMINALS. FOR THIS FORECAST HAVE INDICATED A SCATTERED DECK
OF 2500 FT CEILINGS AFTER 13Z BUT CONFIDENCE IS LOW AS THERE COULD
BE A BRIEF PERIOD OF TIME WHERE CEILINGS FALL BELOW 3000 FT. ANY
PRECIPITATION LOOKS TO REMAIN TO THE NORTH AND WEST OF THE
TERMINALS AND NOT INCLUDED IN THE FORECAST. WINDS WILL BE LIGHT
AND VARIABLE TO CALM OVERNIGHT THEN PICK UP FROM THE SOUTHEAST AND
EVENTUALLY TURN SOUTHERLY AROUND 10 MPH AFTER 17Z.
EXTENDED AVIATION OUTLOOK...RESTRICTIONS EXPECTED AT TIMES...
POSSIBLY THROUGH MID WEEK...AS A FRONT SLOWLY APPROACHES THE
REGION AND STALLS.
&&
.CLIMATE...
RECORD LOW MAX TEMPS WERE ESTABLISHED TODAY AT COLUMBIA...AND
TIED AT AUGUSTA.
AT COLUMBIA (CAE)...THE NEW RECORD LOW MAX TEMPERATURE FOR TODAY WAS 38
DEGREES. THE PREVIOUS RECORD LOW MAX TEMPERATURE WAS 39 DEGREES IN 1902.
AT AUGUSTA (AGS)...THE LOW RECORD LOW MAX TEMPERATURE FOR TODAY
WAS 41 DEGREES...TYING THE RECORD WHICH WAS LAST SET IN 1910.
TEMPERATURE RECORDS FOR COLUMBIA GO BACK TO 1887 AND FOR AUGUSTA
BACK TO 1873.
&&
.CAE WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
GA...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS NORTHERN INDIANA
1200 AM EST THU FEB 19 2015
.SYNOPSIS...
ISSUED AT 1200 AM EST THU FEB 19 2015
PERIODS OF LAKE EFFECT SNOW WILL PERSIST INTO TODAY NORTH OF
HIGHWAY 30...WITH THE HEAVIEST SNOW AND VERY DIFFICULT TRAVEL
CONDITIONS CENTERED ACROSS FAR NORTHERN INDIANA AND SOUTHWEST
LOWER MICHIGAN. DRY OTHERWISE TODAY INTO FRIDAY MORNING WITH
DANGEROUS WIND CHILLS EXPECTED. HIGHS TODAY WILL ONLY RECOVER INTO
THE SINGLE DIGITS ABOVE ZERO...WITH BITTERLY COLD LOWS IN THE
SINGLE DIGITS TO TEENS BELOW ZERO TONIGHT. A WEAK SYSTEM MAY BRING
SOME LIGHT SNOW TO THE REGION BY LATER FRIDAY AFTERNOON INTO
FRIDAY NIGHT. MILDER TERMPERATURES THIS WEEKEND WILL BE OFFSET BY
INCREASING CHANCES FOR ACCUMULATING SNOW AND MIXED PRECIPITATION
LATER SATURDAY INTO SATURDAY NIGHT.
&&
.SHORT TERM...(THIS EVENING THROUGH THURSDAY)
ISSUED AT 336 PM EST WED FEB 18 2015
ELONGATED SFC TROUGH LEFTOVER FM EARLIER MESOVORT THAT DISSIPATED
THROUGH WRN LWR MI STILL SUSTAINING AN INTENSE BAND OF LK EFFECT
SNOW FM SERN LAGRANGE NWWD THROUGH WRN ST JOE. WWD OF THIS PRIMARY
BAND...LESS INTENSE MULTIBANDS CONT TO DVLP W/SOMEWHAT GREATER
ORGANIZATION NOTED ACRS WRN CASS SEWD THROUGH ERN ELKHART.
OUTSIDE THESE AREAS...DRY ENTRAINMENT TAKING ITS TOLL ON DIURNAL
ENHANCEMENT TRYING TO DVLP SOUTH OF HIGHWAY 30 AND SUSPECT LTL IF
ANYTHING WILL MATERIALIZE NOW PRIOR TO SUNSET AND LOSS OF LIMITED
DIURNAL HEATING.
OF NOTE GOING FWD IS XPCD REDVLPMNT OF PRIMARY SINGLE BAND AS CLD
LYR FLW VEERS OVERNIGHT AND LL THERMAL TROUGH MAXIMIZES. BASED ON
EARLY MORNING DVLPMNT/EVOLUTION AND IN LIGHT OF 12Z NAM/CONCURRENT
LTR RUC TRENDS...ANOTHER INTENSE SINGLE BAND XPCD TO DVLP TWD 06Z
ALG THE ERN SHORELINE OF WRN LWR MI AND THEN SHIFT SWD INTO NW IN BY
DAYBREAK THU BFR STALLING OUT NW-SE NORTH OF THE HIGHWAY 30 CORRIDOR
BFR BREAKING UP TWD THU EVENING. WILL ADJUST HIGHLITES TO ADD A
BUFFER STRIP OF SNOW/BLWG SNOW ADVISORY COUNTIES...KOSCIUSKO EAST
THROUGH STEUBEN/DEKALB TO ALIGN W/SRN EXTENT OF LIGHT SNOW SHOWERS
AND MORE SIG GRADIENT FLW THROUGH 03Z.
&&
.LONG TERM...(THURSDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 336 PM EST WED FEB 18 2015
...WEEKEND SYSTEM TO BRING POTENTIAL MIXED PRECIPIATION...
FORECAST PERIOD BEGINS WITH DIMINISHING LES AS INITIAL SETUP AT 00Z
FRI WITH 3-4KFT INVERSION HEIGHTS AND DELTA T OF 25-30C AND SLIGHTLY
VEERING NW FLOW OF 290-330 UNDER THE INVERSION WILL QUICKLY
DISSIPATE AS SURFACE RIDGE AXIS SHIFTS EASTWARD OVER THE AREA.
MODELS OFFERING VARYING SOLUTIONS ON TIMING AND PLACEMENT OF SYSTEMS
ARRIVING THIS WEEKEND. WEAK NORTHERN STREAM CLIPPER WILL APPROACH
THE GREAT LAKES REGION FRIDAY AND OFFER LITTLE MORE THAN
SLIGHT/CHANCE POPS DURING THE DAY FRIDAY. SOUTHERN STREAM SYSTEM
WILL THEN MOVE UP INTO THE TN/OH VALLEY ON SATURDAY. MODELS CONTINUE
TO TREND MORE TOWARDS THE NW WITH TRACK OF SFC LOW WITH GEM MOST
AGGRESSIVE ON PRECIP WITH OVER 1.5 INCHES...ECMWF AND GFS LOWER BUT
STILL RESPECTABLE. WITH TRENDS POINTING TOWARD HIGHER CONFIDENCE IN
CHANCES FOR MEASURABLE PRECIP...HAVE INCREASED POPS SUBSTANTIALLY
SATURDAY AFTERNOON AND NIGHT WITH CAT POPS SE SAT NGT. AS FOR PTYPE
AND AMOUNTS...FURTHER NORTH TRACK WILL INTRODUCE GREATER MIX
POTENTIAL SAT AFTN/EVE ESPECIALLY S/SE PORTIONS AS HIGHS MAY CLIMB
ABOVE FREEZING SAT AFTERNOON AND POSSIBLY HOLD INTO THE EVENING.
FOR NOW HAVE WENT WITH RAIN OR SNOW SATURDAY AFTERNOON WITH LIKELY
NEED TO EXPAND INTO PARTS OF SAT NGT IN LATER FORECASTS. COULD
BECOME QUITE MESSY FOR MUCH OF THE WEEKEND SO STAY TUNED FOR LATER
UPDATES.
FEW CHANGES TO PERIODS BEYOND THE WEEKEND WITH EFFECTS OF THE
WEEKEND SYSTEM POSSIBLY DICTATING AMOUNT/SPEED OF COLD AIR RETURN TO
THE REGION AND IMPACTS IN TERMS OF LAKE EFFECT.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z THURSDAY NIGHT)
ISSUED AT 1200 AM EST THU FEB 19 2015
BITTERLY COLD NORTHWEST FLOW WILL KEEP LAKE EFFECT SNOWS GOING AT
KSBN THROUGH MUCH OF THE TAF CYCLE. CONDITIONS WILL LIKELY
FLUCTUATE BETWEEN LIFR-MVFR...WITH LONGER DURATION LIFR CONDITIONS
EXPECTED THIS MORNING AS A LOW LEVEL TROUGH DROPPING SOUTH
THROUGH WESTERN MICHIGAN HELPS RE-FOCUS BANDING DURING THIS TIME.
BOUNDARY LAYER MODIFICIATION WITHIN TROUGH AND AN ADDED DIURNAL
COMPONENT SHOULD ALLOW SNOW SHOWERS AND TIMES OF IFR-MVFR
RESTRICTIONS TO DEVELOP AROUND KFWA THIS AFTERNOON.
OTHERWISE...WNW WINDS 10-15 KTS EXPECTED TODAY WITH GUSTS NEAR 20
KTS AT TIMES.
&&
.IWX WATCHES/WARNINGS/ADVISORIES...
IN...WIND CHILL ADVISORY UNTIL NOON EST /11 AM CST/ THURSDAY FOR
INZ007>009-012>018-020-022>027-032>034.
WINTER WEATHER ADVISORY UNTIL 7 PM EST /6 PM CST/ THURSDAY FOR
INZ003>006.
MI...WIND CHILL ADVISORY UNTIL NOON EST THURSDAY FOR MIZ080-081.
WINTER WEATHER ADVISORY UNTIL 7 PM EST THURSDAY FOR MIZ079.
WINTER STORM WARNING UNTIL 7 PM EST THURSDAY FOR MIZ077-078.
OH...WIND CHILL ADVISORY UNTIL NOON EST THURSDAY FOR OHZ001-002-004-
005-015-016-024-025.
LM...NONE.
&&
$$
SYNOPSIS...STEINWEDEL
SHORT TERM...T
LONG TERM...FISHER
AVIATION...STEINWEDEL
VISIT US AT WWW.WEATHER.GOV/IWX (ALL LOWER CASE)
FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/NWSNORTHERNINDIANA
WWW.TWITTER.COM/NWSIWX
WWW.YOUTUBE.COM/NWSNORTHERNINDIANA
AREA FORECAST DISCUSSION
NWS GOODLAND KS
831 PM MST FRI FEB 20 2015
.UPDATE...
ISSUED AT 831 PM MST FRI FEB 20 2015
LATEST ESTF SENT OUT WITH MAIN FOCUS TO REDUCE POPS ACROSS THE
FORECAST AREA BASED ON LATEST REGIONAL RADAR TREND. MAIN BATCH OF
EARLY PRECIP MAINLY SHIFTED TO OUR SOUTH...WITH ONLY LIGHT ECHOES
OVER SW PORTIONS OF THE CWA SUGGESTING SPRINKLES SINCE NO OBS
REPORTED ANYTHING. UPSTREAM SCATTERED RETURNS ARE EXPECTED TO MOVE
DOWN ACROSS THE AREA...AND WITH NO MAJOR ORGANIZATION WITH ANY OF
IT HAVE REDUCED POPS TO SCATTERED FOR REST OF TONIGHT. WITH A
SLOW/LOWERING TEMP TREND...WILL CONTINUE A MENTION FOR ANOTHER
HOUR OR SO SCT/ISO -RW...BUT -SW WILL BE MAIN P-TYPE. LITTLE TO NO
ACCUMULATION EXPECTED. SOME MINOR TWEAKS TO CLOUDS AND HOURLY
TEMPS.
&&
.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 00Z TAFS THROUGH 00Z SATURDAY EVENING)
ISSUED AT 441 PM MST FRI FEB 20 2015
MAINLY VFR CONDITIONS EXPECTED FOR THE FORECAST PERIOD. CEILINGS
MAINLY BE A MIX OF BKN050-080 THROUGH 19Z-20Z SATURDAY...THEN
MVFR/VFR WITH BKN025-035. 5-6SM IN SHRASN 02Z-09Z SAT FOR KGLD
AND 04Z-11Z SAT FOR KMCK. VCSH AFT 19Z-20Z AS LOWER CLOUD DECK
MORE PRONOUNCED. WINDS NE 5-15KTS SHIFTING TO THE WNW BY 11Z SAT.
BY 19Z-20Z...WINDS SHIFT BACK TO THE NNE 10-15KTS WITH GUSTS NEAR
25KTS...ESPECIALLY FOR KMCK.
&&
.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 GOODLAND KS
541 PM MST FRI FEB 20 2015
.UPDATE...
ISSUED AT 541 PM MST FRI FEB 20 2015
ESTF UPDATE SENT TO ACCT FOR LATEST TEMP TREND IN HOURLIES AND TO
ADJUST CLOUD COVER. CURRENTLY REGIONAL RADAR LOOP SHOWING LIGHT
PRECIPITATION ECHOES OVER THE CHEYENNE COUNTY COLORADO AND NOW
EXTENDING INTO NW KANSAS. NO REPORTS YET OF ANY HITTING THE GROUND
AT OBS SITES...BUT WITH TEMPS STILL IN THE 40S IN MANY
SPOTS...HAVE LEFT IN -RW WORDING. UPSTREAM...MORE LIGHT ECHOES
STILL YET TO MOVE INTO EASTERN COLORADO...SO NO CHANGES TO POPS AT
THIS TIME.
&&
.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 00Z TAFS THROUGH 00Z SATURDAY EVENING)
ISSUED AT 441 PM MST FRI FEB 20 2015
MAINLY VFR CONDITIONS EXPECTED FOR THE FORECAST PERIOD. CEILINGS
MAINLY BE A MIX OF BKN050-080 THROUGH 19Z-20Z SATURDAY...THEN
MVFR/VFR WITH BKN025-035. 5-6SM IN SHRASN 02Z-09Z SAT FOR KGLD
AND 04Z-11Z SAT FOR KMCK. VCSH AFT 19Z-20Z AS LOWER CLOUD DECK
MORE PRONOUNCED. WINDS NE 5-15KTS SHIFTING TO THE WNW BY 11Z SAT.
BY 19Z-20Z...WINDS SHIFT BACK TO THE NNE 10-15KTS WITH GUSTS NEAR
25KTS...ESPECIALLY FOR KMCK.
&&
.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 GOODLAND KS
441 PM MST FRI FEB 20 2015
.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 00Z TAFS THROUGH 00Z SATURDAY EVENING)
ISSUED AT 441 PM MST FRI FEB 20 2015
MAINLY VFR CONDITIONS EXPECTED FOR THE FORECAST PERIOD. CEILINGS
MAINLY BE A MIX OF BKN050-080 THROUGH 19Z-20Z SATURDAY...THEN
MVFR/VFR WITH BKN025-035. 5-6SM IN SHRASN 02Z-09Z SAT FOR KGLD
AND 04Z-11Z SAT FOR KMCK. VCSH AFT 19Z-20Z AS LOWER CLOUD DECK
MORE PRONOUNCED. WINDS NE 5-15KTS SHIFTING TO THE WNW BY 11Z SAT.
BY 19Z-20Z...WINDS SHIFT BACK TO THE NNE 10-15KTS WITH GUSTS NEAR
25KTS...ESPECIALLY FOR KMCK.
&&
.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.
&&
$$
SHORT TERM...MK
LONG TERM...FS
AVIATION...JN
AREA FORECAST DISCUSSION
NWS LOUISVILLE KY
1022 PM EST Fri Feb 20 2015
...Forecast Update...
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/ Saturday 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/ Saturday FOR
INZ076>079-083-084-089>092.
&&
$$
Update.........RJS
Short Term.....MJ/KJD/BJS
Long Term......KJD
Hydrology......KJD
Aviation.......RAS
AREA FORECAST DISCUSSION
NWS CARIBOU ME
603 PM EST THU FEB 19 2015
.SYNOPSIS...
LOW PRESSURE FORMING NEAR NOVA SCOTIA WILL STRENGTHEN AND ROTATE
INTO NEW BRUNSWICK THIS EVENING. THE LOW WILL MOVE TOWARDS
LABRADOR ON FRIDAY. HIGH PRESSURE WILL CROSS THE REGION FRIDAY
NIGHT THEN MOVE EAST SATURDAY. LOW PRESSURE WILL TRACK NORTHWEST
OF THE REGION SUNDAY.
&&
.NEAR TERM /THROUGH FRIDAY/...
550 PM UPDATE: DIFFICULT FCST IN THE NEAR TERM. RADAR INDICATES A
SERIES OF FAST MOVG BANDS OF MDT TO MARGINAL HVY SNFL MOVG NNW
FROM SRN NEW BRUNSWICK...WITH VERY LITTLE FALLING SN BETWEEN
THEM. IN MY OPINION...THIS COULD MAKE IT DIFFICULT TO REACH WRNG
CRITERIA SNFL WHERE WE STILL HAVE WRNGS. BASED ON LATEST SIM REF
HRRR MODEL OUTPUT...WIDESPREAD SNFL WILL END WITHIN THE NEXT 2 TO
4 HRS OVR SRN ZONES...INCLUDING THE CNTRL ME HIGHLANDS...SO WE
SHOULD BE ABLE TO DROP REMAINING WRNGS THERE.
ACROSS THE N...THE HRRR INDICATES ADDITIONAL BANDING...LIKELY
MULTIPLE BANDING...TO AFFECT THE N FROM NEW BRUNSWICK FROM LATE
EVE INTO THE PREDAWN HRS...AFT A RELATIVE BREAK ERLY TO MID EVE
FROM BANDING. IF ADDITIONAL BANDS ARE PROGRESSIVE RATHER THAN
QUASI-STATIONARY OVR PTNS OF THE WNTR STM WRNG AREA ACROSS THE
N...SNFL TOTALS WILL BE LESS THAN WE ARE ADVERTISING NOW. SO FOR
NOW...WE WILL LET THE CURRENT 6 HRLY SNFL FCSTS FOR BOTH THE
00-06Z AND 06Z-12Z PDS RIDE AND SEA WHAT BANDING MATERIALIZES LATER
TNGT.
OTHERWISE...WE MADE MINOR ADJUSTMENTS TO FCST HRLY TEMPS THRU THE
NGT BASED ON OBSVD HI TEMPS LATE THIS AFTN AND 5 PM OBSVD TEMPS TO
ATTM...UNCHGD FCST LOWS AT 12-13Z FRI.
ORGNL DISC: A DYNAMIC SITUATION CONTINUES TO UNFOLD THIS EVENING.
A COLD UPPER LOW SITUATED IN UPSTATE NEW YORK. LOW PRESSURE IS
DEVELOPING ON THE CYCLONIC SIDE OF THIS UPPER LOW NEAR NOVA SCOTIA
WITH A SECONDARY CENTER IN DOWN EAST MAINE. AS THE UPPER LOW DRAWS
CLOSER TO MAINE...A SHORTWAVE ROTATING AROUND THE UPPER LOW WILL
SHARPEN AND DRAW MOISTURE ALONG MAINE`S EASTERN BORDER TOWARDS THE
CROWN OF MAINE. MOST OF THE SNOW HAS ENDED FOR SOUTHERN
PISCATAQUIS...HANCOCK AND SOUTHERN PENOBSCOT COUNTIES WITH THE
EXCEPTION OF A SQUALL LINE THAT WILL MOVE THROUGH LATER THIS
EVENING. THIS SQUALL LINE WILL MARK THE ENTRANCE OF ANOTHER ARCTIC
AIR MASS AND COULD DROP A QUICK INCH OR TWO WITH POOR VISIBILITY.
THIS LINE IS PROGGED TO CROSS THE BANGOR AREA AROUND 8 T0 9 PM.
HAVE MAINTAINED THE WINTER STORM WARNING FOR THE GREENVILLE AREA
AS THE CONVERGENCE BETWEEN THE SQUALL AND MOISTURE ROTATING BACK
FROM NEW BRUNSWICK COULD GENERATE A FEW ADDITIONAL INCHES. IN
WASHINGTON COUNTY...WILL ALSO EXTEND THE WARNING INTO THE EVENING
AS SNOW SHOWERS CONTINUE TO MOVE ONSHORE INTO THIS EVENING UNTIL
THE SHORTWAVE PIVOTS AND THE UPPER FLOW TURNS MORE SOUTHWESTERLY.
THIS LEAVES AROOSTOOK...NORTHERN PENOBSCOT AND NORTHERN
PISCATAQUIS IN THE WARNING THROUGH TOMORROW MORNING. AS THE UPPER
LOW MOVES FROM UPSTATE NEW YORK TO CENTRAL MAINE
OVERNIGHT...MOISTURE IS EXPECTED TO CONTINUE WRAPPING AROUND THE
NORTH SIDE OF THE UPPER LOW. THE SAINT JOHN VALLEY WILL CONTINUE
TO HAVE MODERATE SNOW INTO FRIDAY MORNING UNTIL THE UPPER LOW
FINALLY MOVES TO NEW BRUNSWICK.
COLD AIR ADVECTION...A TIGHT PRESSURE GRADIENT ON THE BACKSIDE OF
THE LOW AND GOOD MIXING WILL BRING HIGH WINDS ON FRIDAY. GUSTS
WILL REACH UP TO 35 MPH. THIS WILL BRING BLOWING SNOW CONCERNS TO
THE NORTHERN ZONES WHERE THE GREATER AMOUNT OF POWDERY SNOW FELL.
DRIFTING AND AREAS OF LOW VISIBILITY CAN BE ANTICIPATED FOR MUCH
OF AROOSTOOK COUNTY. HIGHS WILL BE IN THE MORNING WITH LITTLE
VARIATION IN TEMPERATURES THROUGH THE DAY. WIND CHILLS WILL DROP
BELOW ZERO AND STAY WELL BELOW ZERO ALL DAY...BUT NOT TO ADVISORY
CRITERIA.
&&
.SHORT TERM /FRIDAY NIGHT THROUGH SUNDAY/...
HIGH PRESSURE WILL BUILD ACROSS THE REGION FRIDAY NIGHT WITH
MOSTLY CLEAR SKIES AND DECREASING WINDS. DEPENDENT ON HOW RAPIDLY
THE WINDS DIMINISH...WIND CHILLS COULD BE A CONCERN FRIDAY NIGHT.
HIGH PRESSURE WILL MOVE EAST SATURDAY WITH INCREASING CLOUDS. LOW
PRESSURE WILL TRACK FROM THE GREAT LAKES TOWARD QUEBEC PROVINCE
SATURDAY NIGHT WITH A WARM FRONT DEVELOPING ALONG THE DOWNEAST
COAST. THE WARM FRONT WILL HELP FOCUS SNOW ACROSS DOWNEAST AREAS
SATURDAY NIGHT WITH LESSER SNOW ACCUMULATIONS NORTHWARD ACROSS THE
REMAINDER OF THE FORECAST AREA. THE LOW WILL TRACK NORTHEAST ALONG
THE SAINT LAWRENCE RIVER VALLEY SUNDAY. GENERALLY EXPECT
PRECIPITATION IN THE FORM OF SNOW ACROSS MUCH OF THE FORECAST AREA
SUNDAY. HOWEVER...UNCERTAINTY EXISTS REGARDING PRECIPITATION TYPES
DOWNEAST DEPENDENT ON HOW MUCH INLAND PROGRESS THE WARM FRONT IS
ABLE TO MAKE. EXPECT A WINTRY MIX COULD OCCUR ACROSS INTERIOR
DOWNEAST AREAS...WITH A WINTRY MIX POSSIBLY TRANSITIONING TO RAIN
ALONG THE DOWNEAST COAST. ALL PRECIPITATION WILL BEGIN TO DIMINISH
SUNDAY AFTERNOON. TEMPERATURES WILL BE AT BELOW NORMAL LEVELS
SATURDAY. TEMPERATURES SUNDAY ARE EXPECTED TO BE AT NEAR
NORMAL...TO SLIGHTLY ABOVE NORMAL...LEVELS.
&&
.LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/...
AT THE START OF THE PERIOD THE EXTENDED MODELS ARE IN GOOD
GENERAL AGREEMENT. A LOW IN THE GULF OF ST LAWRENCE...WITH AN
ASSOCIATED FRONT EXTENDING SW ACROSS NOVA SCOTIA INTO THE NORTH
ATLANTIC. A LOW CENTERED OVER ERN QUEBEC...WITH A TROUGH EXTENDING
SW INTO THE ERN GREAT LAKES. A CLOSED UPPER LEVEL LOW OVER JAMES
BAY AND A CANADIAN HIGH RIDGING INTO SW MAINE WILL COMBINE TO
AFFECT THE WEATHER AT THE START OF THE PERIOD. BY EARLY MON MRNG
THE CANADIAN HIGH WILL BUILD SOUTH INTO THE CNTRL US...AND RIDGE
EAST ACROSS OUR AREA...THE UPPER LOW WITH A POOL OF COLD AIR WILL
MOVE SE INTO SRN QUEBEC. BY MON EVNG THE UPPER LVL LOW WILL MOVE
ACROSS NRN MAINE...AS THE CANADIAN HIGH CONTINUES TO BUILD SOUTH
AND EAST. A NEW LOW WILL MOVE SOUTH OUT OF THE NW CANADA INTO THE
SRN PORTIONS OF HUDSON BAY. BY TUES MRNG THE RIDGE WILL CREST OVER
THE AREA...AS THE NEW LOW OVER SRN HUDSON BAY CONTINUES TO
DEEPEN...ITS ASSOCIATED FRONT MOVES INTO THE CNTRL GREAT LAKES. BY
TUES EVNG THE GFS AND ECMWF DIFFER A BIT ON TIMING...THE GFS MOVES
THE WARM FRONT INTO CNTRL MAINE TUES EVNG...WITH ITS ASSOCIATED
COLD FRONT EXTENDING SW ACROSS THE ERN GREAT LAKES. THE ECMWF TO
NW MAINE...ITS COLD FRONT THROUGH THE CNTRL GREAT LAKES REGION.
THE ECMWF SHOWS A LOW OF THE COAST OF SC. BY WED MRNG THE GFS
MOVES THE TRIPLE POINT TO THE MOUTH OF THE ST LAWRENCE
SEAWAY...WITH THE COLD FRONT EXTENDED SW ALONG THE COAST OF MAINE
INTO SRN NEW ENGLAND. THE ECMWF SHOWS THE COLD FRONT EXTENDED
THROUGH CNTRL MAINE...THE LOW OFF THE COAST OF SC DEEPENS AND
MOVES NE NORTH OF BERMUDA. BY WED EVNG THE GFS MOVES THE COLD
FRONT INTO THE GULF OF MAINE...IT IS ALSO SHOWING A LOW NORTH OF
BERMUDA. THE ECMWF MOVES THE COLD FRONT THROUGH MAINE...MOVES THE
LOW NORTH OF BERMUDA NE TO THE EAST OF CAPE COD SOUTH OF CNTRL
NOVA SCOTIA. BOTH MODELS SHOW A CLOSE UPPER LOW OVER OR JUST EAST
OF JAMES BAY. BOTH SHOW ANOTHER CANADIAN HIGH DIGGING SOUTH
THROUGH THE CNTRL US. BY THURS MRNG THE RIDGE BEGINS TO BUILD EAST
TOWARDS MAINE AS THE POOL OF COLD AIR EXTENDS ACROSS THE AREA. THE
LOCAL AREA WILL REMAIN UNDER THE RIDGE THROUGH THE END OF THE
PERIOD.
LOADED THE SUPERBLEND...NAWAVE 4 FOR SEAS IN THE COASTAL WATERS.
ADDED 15 PERCENT TO WNDS FOR GUSTS OVER LAND...30 PERCENT FOR
GUSTS OVER THE COASTAL WATERS.
&&
.AVIATION /00Z FRIDAY THROUGH TUESDAY/...
NEAR TERM: EXPECT IFR TO LIFR CONDITIONS NORTH OF HUL INTO FRIDAY
MORNING...FOLLOWED BY MVFR CONDITIONS AND STRONG WEST WINDS
GUSTING OVER 30 MPH. FOR BGR AND BHB...CONDITIONS WILL BE MOSTLY
MVFR EXCEPT A SNOW SQUALL PASSING THROUGH LATER THIS EVENING.
THESE TERMINALS WILL BECOME VFR SEVERAL HOURS AFTER THE SQUALL.
SHORT TERM: VFR CONDITIONS ARE EXPECTED FRIDAY NIGHT THROUGH MUCH
OF SATURDAY...THOUGH MVFR CONDITIONS COULD BEGIN TO DEVELOP LATER
SATURDAY. IFR/LIFR CONDITIONS ARE EXPECTED SATURDAY NIGHT INTO
SUNDAY...WITH IMPROVING CONDITIONS LATER SUNDAY INTO SUNDAY
NIGHT. GENERALLY EXPECT VFR CONDITIONS ACROSS THE REGION MONDAY
INTO TUESDAY.
&&
.MARINE...
NEAR TERM: HAVE DROPPED THE SCA WITH GALE CONDITIONS ARRIVING
TOWARDS MIDNIGHT AND CONTINUING INTO FRIDAY NIGHT. GUSTS MAY REACH
40 KTS WITH SEAS BUILDING TOWARDS 12 FEET. FREEZING SPRAY WILL
START TONIGHT AND CONTINUE THROUGH FRIDAY.
SHORT TERM: A GALE WARNING REMAINS IN EFFECT INTO FRIDAY NIGHT.
SMALL CRAFT ADVISORY CONDITIONS ARE THEN EXPECTED SATURDAY THROUGH
SUNDAY. A FREEZING SPRAY ADVISORY FOR MODERATE FREEZING SPRAY WILL
ALSO REMAIN IN EFFECT FRIDAY NIGHT. VISIBILITIES WILL BE REDUCED
IN SNOW AND MIXED PRECIPITATION SATURDAY NIGHT INTO SUNDAY.
&&
.CAR WATCHES/WARNINGS/ADVISORIES...
ME...WINTER STORM WARNING UNTIL 10 AM EST FRIDAY FOR MEZ001>006.
WINTER STORM WARNING UNTIL 10 PM EST THIS EVENING FOR MEZ010-
017-030-032.
MARINE...FREEZING SPRAY ADVISORY FROM 1 AM FRIDAY TO 7 AM EST SATURDAY
FOR ANZ050>052.
GALE WARNING FROM 11 PM THIS EVENING TO 1 AM EST SATURDAY FOR
ANZ050>052.
&&
$$
NEAR TERM...VJN
SHORT TERM...NORCROSS
LONG TERM...NORCROSS
AVIATION...VJN/NORCROSS
MARINE...VJN/NORCROSS
AREA FORECAST DISCUSSION
NWS GRAND RAPIDS MI
920 PM EST FRI FEB 20 2015
LATEST UPDATE...
UPDATE
.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 ROUGHTLY 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 00Z TAFS THROUGH 00Z SATURDAY EVENING)
ISSUED AT 738 PM EST FRI FEB 20 2015
A BURST OF LIGHT SNOW WILL MOVE THROUGH THE TAF SITES THIS EVENING
WITH CONDITIONS TRYING TO DROP FROM VFR TO MVFR. AT THIS
TIME...MOST SITES ARE VFR WITH ONLY A COUPLE OF MVFR VISIBILITIES
NOTED. THE SNOW THIS EVENING SHOULD BE LIGHT FOR THE MOST PART AS
IT IS ASSOCIATED WITH A WEAK SYSTEM. THE EXCEPTION TO THE RULE
WILL BE AT KMKG WHERE SOME LAKE ENHANCEMENT IN SOUTH-SOUTHWEST
FLOW MAY DIP CONDITIONS THERE TO IFR. THE SNOW WILL TAPER OFF
OVERNIGHT LEAVING MVFR CEILINGS BEHIND AT ALL SITES.
FOCUS THEN SHIFTS TO A SYSTEM MOVING ACROSS THE OHIO VALLEY WHICH
MAY SPREAD SOME LIGHT SNOW ACROSS THE I94 TAF SITES ON SATURDAY.
IN GENERAL THINKING MVFR CONDITIONS WILL PREVAIL ON SATURDAY AT
ALL SITES MAINLY DUE TO CEILINGS. THINKING THE SNOW WILL BE
LIMITED. HAVE CONDITIONS AT THE EDGE OF IFR AT KAZO...KBTL AND
KJXN THOUGH AS THEY WILL BE ON THE NORTHERN FRINGES OF THE SNOW
ASSOCIATED WITH THE OHIO VALLEY SYSTEM.
&&
.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 SATURDAY 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
901 PM EST FRI FEB 20 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 00Z TAFS THROUGH 00Z SATURDAY EVENING)
ISSUED AT 704 PM EST FRI FEB 20 2015
-SN TONIGHT...ESPECIALLY THIS EVENING.
LOW PRESSURE JUST WEST OF SUPERIOR HELPING TO GENERATE SOME -SN
ACROSS THE NORTHERN LAKES THIS EVENING. THIS WILL CONTINUE...
DIMINISHING OVERNIGHT. MBL HAS FOUND ITSELF IN A BIT OF A
HOLE...BUT SNOW WILL RETURN THERE SHORTLY. IFR TO MVFR CONDITIONS
EXPECTED. THAT WILL GIVE WAY TO SOME LIGHT LAKE EFFECT -SHSN AND
MVFR TO VFR CIGS ON SATURDAY.
SOUTHERLY BREEZES TONIGHT...A BIT GUSTY IN SPOTS. LLWS MBL/TVC.
LIGHTER WINDS SATURDAY.
&&
.APX WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LH...NONE.
LM...NONE.
LS...NONE.
&&
$$
UPDATE...JAZ
NEAR TERM...KEYSOR
SHORT TERM...JSL
LONG TERM...TJL
AVIATION...JAZ
AREA FORECAST DISCUSSION
NWS GRAND RAPIDS MI
739 PM EST FRI FEB 20 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.
&&
.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 00Z TAFS THROUGH 00Z SATURDAY EVENING)
ISSUED AT 738 PM EST FRI FEB 20 2015
A BURST OF LIGHT SNOW WILL MOVE THROUGH THE TAF SITES THIS EVENING
WITH CONDITIONS TRYING TO DROP FROM VFR TO MVFR. AT THIS
TIME...MOST SITES ARE VFR WITH ONLY A COUPLE OF MVFR VISIBILITIES
NOTED. THE SNOW THIS EVENING SHOULD BE LIGHT FOR THE MOST PART AS
IT IS ASSOCIATED WITH A WEAK SYSTEM. THE EXCEPTION TO THE RULE
WILL BE AT KMKG WHERE SOME LAKE ENHANCEMENT IN SOUTH-SOUTHWEST
FLOW MAY DIP CONDITIONS THERE TO IFR. THE SNOW WILL TAPER OFF
OVERNIGHT LEAVING MVFR CEILINGS BEHIND AT ALL SITES.
FOCUS THEN SHIFTS TO A SYSTEM MOVING ACROSS THE OHIO VALLEY WHICH
MAY SPREAD SOME LIGHT SNOW ACROSS THE I94 TAF SITES ON SATURDAY.
IN GENERAL THINKING MVFR CONDITIONS WILL PREVAIL ON SATURDAY AT
ALL SITES MAINLY DUE TO CEILINGS. THINKING THE SNOW WILL BE
LIMITED. HAVE CONDITIONS AT THE EDGE OF IFR AT KAZO...KBTL AND
KJXN THOUGH AS THEY WILL BE ON THE NORTHERN FRINGES OF THE SNOW
ASSOCIATED WITH THE OHIO VALLEY SYSTEM.
&&
.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 SATURDAY FOR MIZ037-043-
050.
LM...NONE.
&&
$$
SYNOPSIS...TJT
SHORT TERM...TJT
LONG TERM...COBB
AVIATION...DUKE
HYDROLOGY...63
AREA FORECAST DISCUSSION
NWS GAYLORD MI
704 PM EST FRI FEB 20 2015
.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 00Z TAFS THROUGH 00Z SATURDAY EVENING)
ISSUED AT 704 PM EST FRI FEB 20 2015
-SN TONIGHT...ESPECIALLY THIS EVENING.
LOW PRESSURE JUST WEST OF SUPERIOR HELPING TO GENERATE SOME -SN
ACROSS THE NORTHERN LAKES THIS EVENING. THIS WILL CONTINUE...
DIMINISHING OVERNIGHT. MBL HAS FOUND ITSELF IN A BIT OF A
HOLE...BUT SNOW WILL RETURN THERE SHORTLY. IFR TO MVFR CONDITIONS
EXPECTED. THAT WILL GIVE WAY TO SOME LIGHT LAKE EFFECT -SHSN AND
MVFR TO VFR CIGS ON SATURDAY.
SOUTHERLY BREEZES TONIGHT...A BIT GUSTY IN SPOTS. LLWS MBL/TVC.
LIGHTER WINDS SATURDAY.
&&
.APX WATCHES/WARNINGS/ADVISORIES...
MI...WINTER WEATHER ADVISORY UNTIL 7 AM EST SATURDAY FOR MIZ025-031.
LH...NONE.
LM...NONE.
LS...NONE.
&&
$$
NEAR TERM...KEYSOR
SHORT TERM...JSL
LONG TERM...TJL
AVIATION...JAZ
AREA FORECAST DISCUSSION...UPDATED
NWS BILLINGS MT
853 PM MST FRI FEB 20 2015
.UPDATE...
RADAR SHOWING ACTIVITY FILLING IN WEST OF BILLINGS AND FLURRIES
REPORTED SOUTH OF TOWN. HRRR SHOWS THIS COVERAGE INCREASING FOR
THE NEXT FEW HOURS AND THEN SHIFTING SOUTH INTO THE FOOTHILLS AND
MOUNTAINS WITH A DECREASE OVER THE PLAINS. NOT CONFIDENT THAT THIS
WILL OCCUR THAT QUICKLY GIVEN THAT CONTINUED DEVELOPMENT SHOWING
UP ON KTFX RADAR WITH LIGHT UPSLOPE. NO UPDATES TO FORECAST.
BORSUM
&&
.SHORT TERM...VALID FOR SAT AND SUN...
COLD FRONT IS CURRENTLY MAKING ITS WAY ACROSS THE CENTRAL
PORTIONS OF OUR FORECAST AREA AS MILES CITY AND BAKER WINDS ARE
NOW GUSTING OUT OF THE NORTHWEST AND BILLINGS WINDS HAVE RECENTLY
SWITCHED TO THE NORTHEAST. THE BIGGER PUSH OF ARCTIC AIR IS
CURRENTLY OVER THE NORTHEAST CORNER OF THE STATE AND WILL CONTINUE
TO WORK ITS WAY SOUTHWEST THIS AFTERNOON INTO THIS EVENING. EXPECT
THE COLDER AIR TO ARRIVE ACROSS THE BILLINGS AREA BY EARLY EVENING
AND THE FOOTHILLS AREAS BY MID EVENING. MODELS REMAIN FAIRLY
CONSISTENT FROM YESTERDAY AND CURRENT FORECAST STILL LOOKS ON
TRACK. WEB CAMS HAVE SHOWN ON AND OFF SNOW AT COOKE CITY WITH RAIN
AND SNOW SHOWERS ACROSS THE BEARTOOTH/ABSAROKA FOOTHILLS.
A STRONG BAROCLINIC ZONE SETS UP ACROSS THE BEARTOOTH/ABSAROKA
FOOTHILLS THIS EVENING INTO SATURDAY MORNING. THE SYSTEM WILL
CONTINUE TO BE STRONGLY OROGRAPHICALLY AND DYNAMICALLY DRIVEN.
STEEP LAPSE RATES OF 6-8C/KM ALONG WITH STRONG Q-VECTOR
CONVERGENCE WILL MOVE OVER THE MOUNTAINS AND FOOTHILL
LOCATIONS...ESPECIALLY ACROSS THE BEARTOOTH/ABSAROKAS. THE
STRONGEST DYNAMICS MOVE OVER THESE AREAS TONIGHT THROUGH LATE
MORNING ON SATURDAY. WILL CONTINUE WITH LIKELY TO CATEGORICAL POPS
ALONG AND WEST OF A ROUNDUP-BILLINGS-SHERIDAN LINE TONIGHT THROUGH
SATURDAY MORNING. MODELS REMAIN CONSISTENT IN PAINTING A BAND OF
DECENT PRECIP JUST OFF THE BEARTOOTH FOOTHILLS. TIME HEIGHTS SHOW
STRONG LIFT AND INSTABILITY ACROSS THIS AREA AS WELL. AS A
RESULT...WILL BE ISSUING A SNOW ADVISORY FOR EASTERN
CARBON...NORTHERN STILLWATER...AND NORTHERN SWEETGRASS
COUNTIES...AS WELL AS THE LIVINGSTON AREA FOR THIS EVENING THROUGH
SATURDAY EVENING. WILL LEAVE BILLINGS AND SHERIDAN OUT OF ANY
ADVISORIES AT THIS TIME BUT WILL NEED TO WATCH THIS DURING THE
EVENING TO SEE HOW THINGS UNFOLD. THE SYSTEM MOVES OUT OF THE AREA
FAIRLY QUICKLY SATURDAY NIGHT SO THE SNOW SHOULD BE ENDING FROM
NORTH TO SOUTH SATURDAY EVENING.
TEMPERATURES WILL RISE VERY LITTLE IF AT ALL SATURDAY FROM THE
MORNING LOWS WITH READINGS IN THE LOWER TO MIDDLE 20S. A SECONDARY
SHOT OF MUCH COLDER AIR ARRIVES DURING THE AFTERNOON RESULTING IN
SLOWLY FALLING TEMPERATURES. OVERNIGHT LOWS SATURDAY NIGHT WILL BE
SOME OF THE COLDEST WE HAVE FELT IN QUITE A FEW WEEKS WITH
READINGS IN THE SINGLE DIGITS ABOVE AND BELOW ZERO...WITH HIGHS
SUNDAY ONLY IN THE TEENS TO LOWER 20S. HOOLEY
.LONG TERM...VALID FOR MON...TUE...WED...THU...FRI...
AN UNSETTLED NORTH TO NORTHWEST FLOW ALOFT WILL PERSIST
THROUGHOUT THE EXTENDED PERIOD. LEE-SIDE TROUGHING WILL RETURN
MONDAY INTO TUESDAY RESULTING IN BREEZY TO WINDY CONDITIONS ALONG
WITH WARMER TEMPERATURES. ANOTHER COLD FRONT BACKS INTO THE AREA
FROM THE NORTHEAST LATE TUESDAY NIGHT INTO WEDNESDAY BRINGING A
COLD EASTERLY SURFACE FLOW THROUGH THE REMAINDER OF THE WEEK.
TEMPERATURES WILL TURN COLDER WEDNESDAY THROUGH FRIDAY. MODELS
SHOW A GOOD CHANCE FOR ACCUMULATING SNOW ALONG AND BEHIND THE
FRONT WEDNESDAY INTO THURSDAY. TEMPERATURES WILL WARM INTO THE 40S
TO LOWER 50S TUESDAY BEFORE DROPPING BACK INTO THE 20S AND 30S BY
THE END OF THE WEEK. HOOLEY
&&
.AVIATION...
SNOW SHOWERS ARE POSSIBLE OVERNIGHT AND INTO TOMORROW MAINLY WEST
OF A ROUNDUP...TO BILLINGS...TO SHERIDAN LINE...SCATTERED SHOWERS
ARE POSSIBLE ACROSS THE REST OF THE AREA. THESE SHOWERS WILL
PRODUCE BRIEF BUT AT TIMES HEAVY SNOWFALL. FLIGHT CONDITIONS WILL
VARY BETWEEN MOST VFR TO MVFR CONDITIONS AND IFR CONDITIONS IN
THE HEAVIER SNOWFALL. MOUNTAIN OBSCURATIONS WILL ALSO PREVAIL
THROUGH TOMORROW. REIMER
&&
.PRELIMINARY POINT TEMP/POPS...
SAT SUN MON TUE WED THU FRI
-----------------------------------------------------------
BIL 022/024 002/020 008/037 027/050 031/044 018/031 015/035
67/S 20/B 00/U 11/B 23/W 32/S 21/B
LVM 021/025 902/020 002/038 025/051 031/046 022/036 017/038
97/S 20/U 00/U 11/B 23/W 32/S 22/J
HDN 020/027 006/025 007/037 023/049 027/043 017/030 012/034
66/S 20/B 00/U 11/B 23/W 32/S 11/B
MLS 018/019 903/018 005/037 024/044 022/033 009/025 007/029
33/S 10/B 00/U 11/B 23/J 32/S 11/B
4BQ 018/024 901/019 002/035 022/046 024/040 012/029 008/033
44/S 10/U 00/U 01/B 23/W 32/S 11/B
BHK 012/014 910/014 000/035 021/038 016/026 001/020 000/024
62/S 10/B 00/N 11/B 23/J 21/B 01/B
SHR 022/025 002/017 902/032 020/046 024/042 016/028 011/031
68/S 30/B 00/U 01/B 23/W 32/S 22/J
&&
.BYZ WATCHES/WARNINGS/ADVISORIES...
MT...WINTER WEATHER ADVISORY IN EFFECT UNTIL MIDNIGHT MST SATURDAY
NIGHT FOR ZONES 34-39-41-65.
WINTER STORM WARNING IN EFFECT UNTIL 5 AM MST SUNDAY FOR
ZONES 38-56-66-67.
WY...WINTER STORM WARNING IN EFFECT UNTIL 5 AM MST SUNDAY FOR ZONE
98.
&&
$$
WEATHER.GOV/BILLINGS
AREA FORECAST DISCUSSION
NWS HASTINGS NE
316 PM CST THU FEB 19 2015
...LACK OF MODEL CONSISTENCY LEADS TO LOW CONFIDENCE AND DIFFICULT
PREDICTABILITY OF SYSTEM THIS WEEKEND...
.SHORT TERM...(THIS EVENING THROUGH FRIDAY)
ISSUED AT 316 PM CST THU FEB 19 2015
ALOFT: THE FLOW OVERHEAD WAS NW AND WILL GRADUALLY BACK TO W THRU
TOMORROW AS THE DEEP ERN USA TROF LIFTS OUT AND HEIGHTS FALL OVER
THE WRN USA...IN RESPONSE TO A MAJOR RIDGE BUILD OVER THE E PAC/AK.
THE FIRST OF SEVERAL WEAK SHORTWAVE TROFS WILL APPROACH OVER CO LATE
TOMORROW.
SURFACE: HIGH PRES WAS OVER THE MID MS VALLEY AND HEADING INTO THE
ERN USA. A CLIPPER WAS ORGANIZING AND WILL DIVE ACROSS THE CANADIAN
PRAIRIES INTO ND TONIGHT AND INTO MN TOMORROW. THE FRONT SEPARATING
ARCTIC AIR FROM DOWNSLOPE WARMED AIR TO THE W WAS OVER THE PANHANDLE
DOWN ALONG THE CO-KS BORDER. THIS CLIPPER WILL SHOVE THE FRONT E
ACROSS THE FCST AREA TONIGHT.
REST OF THIS AFTERNOON: DECREASING CLOUDS AS SUBSIDENCE OVERSPREADS
BEHIND A DEPARTING SHORTWAVE TROF. THE NW-SE ORIENTED BAND OF WAA-
DRIVEN LIGHT SNOW /OVER ERN NEB/ WILL REMAIN E AND CONT MOVING AWAY.
WE DO NEED TO WATCH THIS BANK OF 3-4K FT CLOUD THAT HAS DEVELOPED
FROM THE TRI-CITIES N AND E. IF THIS DOESNT GET SCOURED OUT THIS
EVENING...IT COULD BE A HEADACHE MOST OF THE NIGHT AND COULD
DERAIL THE TEMP FCST.
WE DID NOTE A BRIEF PERIOD OF LIGHT SNOW/FLURRIES OVER THE FAR NE
FRINGE OF THE FCST AREA AT EARLY AFTERNOON FROM ERN NANCE DOWN TO NE
POLK COUNTIES.
TONIGHT: VARIABLE BETWEEN M/CLEAR AND P/CLOUDY AT TIMES. GIVEN THAT
CLOUDS SUPPRESSED TEMPS OVER THE NE HALF OF THE FCST AREA TODAY...
THE PREVIOUS FCST DID NOT ALLOW FOR ANY ROOM FOR TEMPS TO DROP FROM
CURRENT LEVELS. SO LOWERED TEMPS ABOUT 3F FROM THE TRI-CITIES N AND
E.
FRI: INCREASING CLOUDS WITH CONSIDERABLY WARMER TEMPS. COULD SEE
SOME SPRINKLES OR A LITTLE LIGHT RAIN MOVE IN FROM THE W AFTER 3 PM
AS MOISTURE/LIFT MOVE IN. IF ANYTHING FALLS...IT WILL PROBABLY TAKE
THE FORM OF SPRINKLES AS CLOUD BASES WILL STILL BE AROUND 10K FT.
LOWERED TEMPS SLIGHTLY BELOW THE PREVIOUS FCST DUE TO INCREASING
THICK CLOUD COVER.
.LONG TERM...(FRIDAY NIGHT THROUGH THURSDAY)
ISSUED AT 316 PM CST THU FEB 19 2015
THE WEEKEND POTENTIAL FOR PRECIPITATION HAS BEEN VERY DIFFICULT
TO FORECAST WITH REGARDS TO TIMING...COVERAGE AND PRECIP AMOUNTS
UNDER THIS NORTHWESTERLY FLOW ALOFT. MOST OF THE ATTENTION IN THIS
DISCUSSION WILL BE FOCUSED ON THAT UNCERTAINTY AND POTENTIAL
WEATHER WE COULD SEE FRIDAY NIGHT THROUGH SUNDAY NIGHT.
TEMPERATURES FOR THE MOST PART WILL BE BELOW NORMAL. TUESDAY LOOKS
TO BE THE WARMEST DAY OVERALL FOR THE OUTLOOK AREA...WITH HIGH
TEMPERATURES RANGING FROM THE UPPER 30S TO MID 40S.
THE WEEKEND PRECIPITATION FIASCO CONTINUES. UNFORTUNATELY THE
MODELS CONTINUE TO LACK DAY TO DAY CONSISTENCY THROUGH THE
WEEKEND...AND FORECAST CONFIDENCE FOR TIMING AND COVERAGE
CONTINUES TO BE ON THE LOW TO MODERATE SIDE OF THE SPECTRUM. WITH
REGARDS TO PRECIPITATION...THE MOST CONSISTENCY FOR TODAYS
FORECAST PACKAGE LOOKS TO BE BETWEEN 00Z AND 12Z SATURDAY AND
AGAIN FROM 00Z TO 12Z SUNDAY...WHERE THE MOST AGREEMENT BETWEEN
THE NAM/GFS/ECMWF/SREF CURRENTLY LIES. MODELS ARE SUGGESTING A
LULL PERIOD BETWEEN THESE TWO ROUNDS WHERE WE COULD BE DRY. FOR
THOSE PAYING CLOSE ATTENTION...THE FORECAST HAS BEEN SIGNIFICANTLY
MODIFIED FROM 24 HOURS AGO. WE ARE NOW CALLING FOR ABOUT ONE TO
TWO INCHES OF SNOW ACROSS OUR SOUTH/SOUTHWESTERN COUNTIES. THESE
ARE THE HIGHER AMOUNTS...ELSEWHERE ITS GENERALLY AROUND A COUPLE
TENTHS OF AN INCH TO ABOUT AN INCH. THE PREVIOUS FORECAST PACKAGE
WAS CALLING FOR ONE TO FOUR INCHES.
TAKING A LOOK AT FORECAST SOUNDINGS...IT DOES APPEAR THAT WE MAY
GET A SHOT AT RAINFALL GENERALLY SOUTH OF HIGHWAY 6 BEFORE
PRECIPITATION TURNS OVER TO ALL SNOW. THIS IS THE BIGGEST CHANGE
FROM THE PREVIOUS FORECAST...WHERE PREVIOUSLY THIS QPF WOULD HAVE
BEEN ALL SNOW. HIGH TEMPERATURES FRIDAY AFTERNOON ARE CURRENTLY
FORECAST TO BE AROUND THE LOWER 40S TO LOWER 50S...SO DOMINANT
PRECIPITATION TYPE GOING INTO THE FIRST FEW HOURS OF THIS FORECAST
PERIOD SHOULD BE RAINFALL FOR AREAS SOUTH OF HIGHWAY 6...BUT NORTH
OF HIGHWAY 6 WHERE COOLER TEMPS ARE FORECAST WE WILL HAVE A CHANCE
FOR RAIN OR SNOW. THIS WILL ALL DEPEND ON THE LOW LEVEL WETBULB
TEMPERATURES AND THICKNESS OF THE DRY LAYER NEAR THE SURFACE
FRIDAY NIGHT. EXACT LOCATION OF THIS CUTOFF LINE BETWEEN RAIN AND
SNOW MAY CHANGE. IT WILL EVENTUALLY SWITCH TO ALL SNOW FRIDAY
NIGHT...AND THE BETTER CHANCES CONTINUE TO BE ACROSS NORTH CENTRAL
KANSAS. THE TIMING AND OVERALL COVERAGE ARE THE MAIN
CHALLENGES...BUT AT LEAST THE TIME FRAME BETWEEN 00Z AND 12Z
SATURDAY APPEARS TO BE CONSISTENT FOR PRECIPITATION CHANCES. THERE
IS A CHANCE FOR AN ADDITIONAL ROUND OF EITHER RAIN OR SNOW
SATURDAY AFTERNOON...MAINLY ACROSS OUR SOUTHWEST WHERE HIGHS COULD
GET UP NEAR 40 DEGREES. THIS COULD LAST FOR A FEW HOURS BEFORE
TURNING OVER TO ALL SNOW SATURDAY NIGHT. THIS WILL IN FACT BE
WHERE WE WILL PICK UP THE MOST SNOW...BETWEEN 00Z AND 12Z SUNDAY.
FORCING IS REALLY WEAK DURING THE ENTIRE EVENT. INITIALLY WE GET
THE COLD FRONT AHEAD OF HIGH PRESSURE BUILDING IN FROM THE
NORTH...AND A CONVERGENCE ZONE SETS UP IN THE LOW TO MID
LEVELS...BUT THEREAFTER MAINTENANCE FOR PRODUCING PRECIPITATION IS
GOING TO BE TOUGH UNDER THIS NORTHWESTERLY FLOW PATTERN. PICKING
OUT WHICH SMALL PIECES ENERGY WILL DEVELOP PRECIPITATION WILL BE
INTERESTING. I WOULD NOT BE SURPRISED IF SNOWFALL AMOUNTS CHANGE
AGAIN. PERHAPS ANOTHER DECREASE IN AMOUNTS? NOT SURE AT THIS TIME.
THAT BEING SAID...LEANED HEAVILY TOWARDS THE GFS AND SREF FOR THIS
FORECAST.
&&
.AVIATION...(FOR THE 18Z KGRI/KEAR TAFS THROUGH 18Z FRI AFTERNOON)
ISSUED AT 1143 AM CST THU FEB 19 2015
THIS AFTERNOON: MULTI-LAYERED VFR CIGS AT OR ABOVE 10K FT WILL
GRADUALLY BECOME SCT. SSE WINDS WILL GUST TO AROUND 20 KTS.
CONFIDENCE: HIGH
TONIGHT: VFR WITH FEW-SCT CLOUDS AT OR ABOVE 18K FT. DAYTIME
GUSTINESS WILL SUBSIDE WITH WINDS BECOMING STEADY AROUND 10 KTS
FROM THE S. WINDS SHIFT TO WSW LATE. THE 15Z RAP MODEL SUGGESTS
POTENTIAL FOR MARGINAL LLWS WITH 40 KTS AS LOW AS 1200 FT. ALL
OTHER GUIDANCE IS WEAKER SO LLWS WAS NOT INCLUDED JUST YET.
CONFIDENCE: HIGH EXCEPT MEDIUM ON LLWS POTENTIAL. LATER TAFS
ISSUANCES MAY NEED TO HAVE IT.
FRI THRU 18Z: MULTI-LAYERED VFR CIGS INVADE AT OR ABOVE 20K FT.
EXPECT MID-MORNING WSHFT TO WNW. CONFIDENCE: MEDIUM
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
KS...NONE.
&&
$$
SHORT TERM...HALBLAUB
LONG TERM...GUERRERO
AVIATION...HALBLAUB
AREA FORECAST DISCUSSION
NWS HASTINGS NE
1143 AM CST THU FEB 19 2015
.UPDATE...
ISSUED AT 1143 AM CST THU FEB 19 2015
NO SIGNIFICANT ADJUSTMENTS REQUIRED. GUIDANCE IS RUNNING A LITTLE
TOO LIGHT ON WIND SPEEDS. SO FCST SPEEDS WERE BUMPED UP.
A WEAK SHORTWAVE TROF WAS MOVING SE OUT OF WY/MT. ONCE THIS TROF
PASSES...THERE WILL BE A SUBSTANTIAL DECREASE IN CLOUDS ONCE THIS
TROF PASSES.
THE NW-SE BAND OF PRIMARILY MID-LVL CLOUDS IS BEING GENERATED BY
WAA. WE HAVE NOTEDA SUBSTANTIAL INCREASE IN REFLECTIVITY OVER THE
PAST 1-2 HRS. LIGHT SNOW /-SN/ IS NOW FALLING AT COLUMBUS WITH A
VIS OF 5 MI. WILL UPDATE THE FCST TO INCLUDE SOME -SN WITH A
BUFFER OF SOME FLURRIES N AND E OF GRAND ISLAND /GRI/.
UPDATE ISSUED AT 748 AM CST THU FEB 19 2015
SENT A QUICK UPDATE AS OUR HOURLY TEMPS/DWPTS WERE RUNNING TOO LOW
COMPARED TO REALITY. ALSO BEEFED UP SKYCOVER OVER THE NE 2/3 OF
THE FCST AREA THRU MIDDAY TO BETTER REFLECT CURRENT CONDITIONS.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 400 AM CST THU FEB 19 2015
SATELLITE AND OBSERVATIONS SHOW MID LEVEL CLOUDS ACROSS THE FORECAST
AREA EARLY THIS MORNING. THE CLEARING LINE IS MOVING TOWARD THE
WESTERN PART OF THE FORECAST AREA...WITH SOME CIRRUS MOVING IN
BEHIND THAT.
A WEAK UPPER LEVEL WAVE WILL MOVE ACROSS THE AREA TODAY AND COULD
BRING SOME FLURRIES MAINLY TO THE EASTERN PART OF THE FORECAST AREA.
THE SURFACE PRESSURE GRADIENT TIGHTENS AS A SURFACE HIGH MOVES TO
THE EAST. THE WINDS WILL TURN TO THE SOUTH AND INCREASE THIS
MORNING...BUT THE WINDS ALOFT ARE ONLY 20 TO 25 KTS SO ONLY EXPECT
BREEZY CONDITIONS. THE ARCTIC AIR MASS WILL REMAIN IN PLACE AND
TEMPERATURES WILL ONLY REACH INTO THE 20S IN THE EAST WHERE THERE
WILL BE MORE CLOUDS. THE WESTERN PART OF THE FORECAST AREA COULD BE
IN THE 30S TO AROUND 40 DEGREES WITH A LITTLE MORE SUNSHINE AND SOME
WARM ADVECTION. THE WARM ADVECTION CONTINUES INTO TONIGHT AND PUSHES
THE COLDEST AIR TO THE EAST. LOWS WILL BE IN THE TEENS TO AROUND 20
DEGREES.
.LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 400 AM CST THU FEB 19 2015
THE MAIN CHALLENGE IS A WINTER SYSTEM HITTING FRIDAY NIGHT THROUGH
SATURDAY NIGHT.
NUMERICAL MODELS ARE NOT IN THE GREATEST AGREEMENT WITH TIMING AS
THE ECMWF HITS MORE QPF FRIDAY NIGHT...WHILE THE NAM AND GFS FOCUS
MORE ON SATURDAY MORNING. NONETHELESS...WE ARE LIKELY TO GET SOME
ACCUMULATION WITH THIS WAVE COMING IN WITHIN PROGRESSIVE WEST FLOW.
AT THIS TIME...IT STILL LOOKS MORE FOCUSED IN OUR SOUTH/SOUTHWEST.
WE COULD BE IN FOR A 3 TO 5 INCH ACCUMULATION IN OUR SOUTH/SOUTHWEST
IF SNOW LASTS LONG ENOUGH. I WOULD HAVE RAISED CHANCES OF
PRECIPITATION HIGHER THAN LIKELY IN OUR SOUTH...BUT THERE IS JUST
NOT ENOUGH AGREEMENT WITH TIMING TO GO ANY HIGHER FOR NOW. I PLAN ON
FOLLOWING CLOSER TO WPC GUIDANCE WITH SNOW FALL...GENERALLY ONE TO
THREE INCHES FOR MOST AREAS...GETTING NEAR 4 INCHES OR SO IN OUR FAR
SOUTH/SOUTHWEST...WITH A LOCAL 5 INCH AMOUNT NOT OUT OF THE
QUESTION...THE WAY IT LOOKS NOW. KEEPING THIS ALL IN THE ADVISORY
REALM OR LESS. OUR NORTH STILL HAS VERY LITTLE SNOW IN THE FORECAST.
A SECOND MINOR WAVE IS POSSIBLE SATURDAY NIGHT...AND I UPTICKED SNOW
TO NEAR HALF AN INCH WITH THIS. FOR NOW...I KEPT ANY MIXED
PRECIPITATION OUT OF THE FORECAST FRIDAY NIGHT AS FORECAST SOUNDINGS
STILL DO NOT SEEM TO SUPPORT THIS FOR NOW.
CONFIDENCE IS NOT ALL THAT HIGH WITH TIMING OF THIS SYSTEM. DID NOT
STRAY A WHOLE LOT FROM THE SUPERBLEND/PREVIOUS FORECAST FOR
TEMPERATURES. NAM TEMPERATURES LOOK RATHER WEIRD...WHICH TENDS TO
AFFECT MANY OF OUR CONSRAW AND EVEN SUPERBLEND POPULATED DATA...SO
GENERALLY NO HUGE SWEEPING CHANGES. AGAIN...IF THERE IS ANY
NOTICEABLE CHANGE...IT WOULD BE THE INCREASE OF PROBABILITY OF
PRECIPITATION IN THE SOUTH/SOUTHWEST FRIDAY NIGHT INTO SATURDAY
MORNING AND A BUMP UP A BIT IN SNOW AMOUNTS IN OUR NORTH CENTRAL
KANSAS/SOUTHWEST CWA AREA.
BESIDES THE BRIEF SEASONABLY WARM DAY ON FRIDAY BEFORE MORE COLD AIR
COMES IN WITH THE EXPECTED WAVE...WE SHOULD REMAIN BELOW NORMAL AND
STUCK IN THIS PATTER OF BEING BELOW NORMAL...WITH THE MAIN THRUST OF
COLD AIR REMAINING EAST OF OUR REGION...INTO THE EASTERN HALF OF THE
UNITED STATES.
&&
.AVIATION...(FOR THE 18Z KGRI/KEAR TAFS THROUGH 18Z FRI AFTERNOON)
ISSUED AT 1143 AM CST THU FEB 19 2015
THIS AFTERNOON: MULTI-LAYERED VFR CIGS AT OR ABOVE 10K FT WILL
GRADUALLY BECOME SCT. SSE WINDS WILL GUST TO AROUND 20 KTS.
CONFIDENCE: HIGH
TONIGHT: VFR WITH FEW-SCT CLOUDS AT OR ABOVE 18K FT. DAYTIME
GUSTINESS WILL SUBSIDE WITH WINDS BECOMING STEADY AROUND 10 KTS
FROM THE S. WINDS SHIFT TO WSW LATE. THE 15Z RAP MODEL SUGGESTS
POTENTIAL FOR MARGINAL LLWS WITH 40 KTS AS LOW AS 1200 FT. ALL
OTHER GUIDANCE IS WEAKER SO LLWS WAS NOT INCLUDED JUST YET.
CONFIDENCE: HIGH EXCEPT MEDIUM ON LLWS POTENTIAL. LATER TAFS
ISSUANCES MAY NEED TO HAVE IT.
FRI THRU 18Z: MULTI-LAYERED VFR CIGS INVADE AT OR ABOVE 20K FT.
EXPECT MID-MORNING WSHFT TO WNW. CONFIDENCE: MEDIUM
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
KS...NONE.
&&
$$
UPDATE...HALBLAUB
SHORT TERM...JCB
LONG TERM...HEINLEIN
AVIATION...HALBLAUB
AREA FORECAST DISCUSSION
NWS RALEIGH NC
630 AM EST THU FEB 19 2015
.SYNOPSIS...FRIGID HIGH PRESSURE WILL BUILD OVER THE AREA THROUGH
FRIDAY... BRINGING NEAR RECORD COLD TEMPERATURES AND VERY LOW WIND
CHILLS. ANOTHER STORM SYSTEM WILL APPROACH FROM THE WEST EARLY
SATURDAY... AFFECTING THE REGION OVER THE WEEKEND.
&&
.NEAR TERM /TODAY THROUGH TONIGHT/...
AS OF 235 AM THURSDAY...
...ADVISORY FOR BLACK ICE NORTHERN SECTIONS THIS MORNING AND WIND
CHILL ADVISORY CONTINUES IN EFFECT THROUGH 9 AM FRIDAY...
WILL HOLD ONTO THE WINTER WEATHER ADVISORY FOR BLACK ICE... AS
YESTERDAY`S SNOW SHOWERS COMBINED WITH AREAS WHERE SNOWMELT/ICEMELT
HAS REFROZEN HAS RESULTED IN AREAS OF BLACK ICE.
THE ADVERTISED POLAR AIR SURGE HAS BEGUN WITH 2 AM TEMPS ALREADY
DOWN INTO THE TEENS OVER MUCH OF THE NRN PIEDMONT AND DEWPOINTS WELL
BELOW ZERO. WINDS HAVE PERIODICALLY GUSTED ABOVE 20 MPH AT MANY
LOCATIONS BUT THE STRONGER WINDS AND GUSTS HAVE BEEN VERY ERRATIC SO
FAR... PROBABLY DUE IN PART TO SUBTLE DECOUPLING NOTED ON RAP BUFR
FORECAST SOUNDINGS. AFTER SUNRISE HOWEVER... WE SHOULD BEGIN TO MIX
MORE FULLY UP THROUGH THE LOWEST 3-4 KFT WITH STEADY DEEP COLD AIR
ADVECTION... ALLOWING FOR GREATER MOMENTUM TRANSFER DOWN TO THE
SURFACE. CONSENSUS OF MODEL FORECAST WINDS THROUGH THE MIXED DEPTH
TODAY SUPPORT PERIODIC GUSTS REACHING AS HIGH AS 20 TO 25 MPH...
WITH SUSTAINED WINDS MOSTLY BETWEEN 9 AND 17 MPH. AFTER LOWS THIS
MORNING FROM 10 TO 19 DEGREES... TEMPS SHOULD RISE MINIMALLY TO
HIGHS FROM 16 TO 25... ADHERING CLOSELY TO THE COOLER GFS-BASED
STATISTICAL GUIDANCE WHICH IS SUPPORTED BY YESTERDAY`S HIGHS
UPSTREAM OVER THE WRN OH VALLEY. STILL EXPECT TEMPS TO DROP TO THE 3
BELOW TO 7 ABOVE RANGE FOR LOWS TONIGHT... AGAIN ON THE COOL SIDE OF
GUIDANCE WITHIN THIS ANOMALOUSLY COLD AIR MASS. WIND CHILLS THIS
MORNING SHOULD MOSTLY BE IN THE 5 BELOW TO 8 ABOVE RANGE... RISING
TO 1 ABOVE TO 13 ABOVE THIS AFTERNOON BEFORE DROPPING BACK DOWN
BELOW ZERO AFTER NIGHTFALL... BOTTOMING OUT OVERNIGHT TO BETWEEN 3
BELOW (SOUTH) AND 15 BELOW (NORTH)... DESPITE WIND SPEEDS FALLING
OFF A BIT TONIGHT. THE WIND CHILL ADVISORY WILL BE MAINTAINED AS IS.
WITH SUBSIDENCE AND DRY/STABLE AIR ALOFT... EXPECT MOSTLY CLEAR
SKIES TODAY/TONIGHT... EXCEPT FOR A LIKELY PERIOD OF FLAT BROKEN
CLOUDS THIS AFTERNOON. -GIH
&&
.SHORT TERM /FRIDAY THROUGH FRIDAY NIGHT/...
AS OF 305 AM THURSDAY...
VERY COLD TEMPS PERSIST. WINDS WILL CONTINUE TO DIE DOWN FRI
MORNING... STAYING LIGHT AS THE CENTER OF THE POLAR HIGH SETTLES
OVER THE REGION FRI AFTERNOON/EVENING... THEN SHIFTS ENE OFF THE
COAST FRI NIGHT. THE COLD VORTEX OVER MAINE EARLY FRI SHIFTS TO THE
NE THROUGH FRI NIGHT... RESULTING IN A FLATTENING MID LEVEL FLOW
OVER THE SOUTH-CENTRAL AND SOUTHEAST STATES AND EVENTUALLY
INCREASING DPVA AS HEIGHTS SLOWLY FALL OVER THE SRN PLAINS. AS THE
850 MB ANTICYCLONE MOVES FROM THE GULF FRI MORNING EASTWARD AND OFF
THE SE COAST THROUGH FRI NIGHT... THE INFLUX OF GULF MOISTURE INTO
THE MIDSOUTH AND SOUTHEAST WILL STRENGTHEN... AND CLOUDS WILL
INCREASE FROM WEST TO EAST OVER NC AS MOIST UPGLIDE INITIALLY WELL
ALOFT STARTS TO DEEPEN GROUNDWARD. THERE REMAINS A SUBSTANTIAL DRY
SUBCLOUD LAYER OVER MUCH OF THE CWA INTO FRI NIGHT... AND THIS IS
REFLECTED IN A LACK OF PRECIP OVER ALL BUT PERHAPS THE FAR NW
PORTION OF THE CWA LATE FRI NIGHT. THE NAM IS MUCH FASTER THAN THE
GFS/ECMWF IN BRINGING PRECIP INTO THE NW... AND FOR NOW HAVE
CONTINUED TO LEAN TOWARD A BIT SLOWER AND HENCE DRIER SOLUTION...
WITH JUST A SLIGHT CHANCE POP IN THE NW LATE FRI NIGHT. THE THERMAL
AND MOISTURE STRUCTURE ON FORECAST SOUNDINGS SUPPORT AN INITIAL
PTYPE OF MOSTLY LIGHT SNOW... MIXING WITH A LITTLE LIGHT SLEET...
BUT THESE EARLY HOURS OF PRECIP SHOULD BE QUITE LIGHT. EXPECT HIGHS
IN THE 20S FRI (COOLEST NE) AND LOWS FRI NIGHT OF 11-22 (AGAIN
COOLEST NE). TEMPS SHOULD REACH LOWS EARLY FRI NIGHT THEN LEVEL OFF
OR EVEN RISE A DEGREE OR TWO LATE AS SKIES BECOME OVERCAST. -GIH
&&
.LONG TERM /SATURDAY THROUGH WEDNESDAY/...
AS OF 325 AM THURSDAY...
SATURDAY AND SATURDAY NIGHT: A MODIFIED ARCTIC SURFACE HIGH OVER THE
AREA ON SATURDAY MORNING WILL SHIFT EASTWARD AND OFFSHORE ON
SATURDAY... LEAVING BEHIND A COLD/DRY LOW LEVEL AIRMASS.
MEANWHILE... S/W ENERGY AND AN ASSOCIATED SURFACE LOW OVER THE
SOUTHERN PLAINS ON SATURDAY MORNING WILL LIFT NORTHEASTWARD INTO THE
OHIO VALLEY. BOTH THE ECMWF AND GFS HAVE TREND DRIER OVER CENTRAL
NC... WITH ANY PRECIP DEVELOPING FROM THE WAA OVER THE AREA. AT THIS
TIME THE NORTHWEST PIEDMONT STANDS THE BEST CHANCE OF SEEING SOME
PRECIP. GIVEN THE ANTECEDENT SURFACE AIRMASS EXPECT ANY PRECIP WOULD
START OUT AS SNOW SATURDAY MORNING... THEN TRANSITION TO FREEZING
RAIN AND EVENTUALLY RAIN AS THE SURFACE HIGH CONTINUES TO SHIFT AWAY
FROM THE AREA... RESULTING IN AN INSITU CAD EVENT. CONFIDENCE IS LOW
WITH REGARD TO HOW MUCH PRECIP WE WILL SEE. THUS... HAVE TRIMMED
BACK ON POPS AND WILL ALLOW TEMPS TO WARM UP A BIT QUICKER. THE NAM
IS THE MOST AGGRESSIVE WITH DEVELOPING PRECIP ACROSS MOST OF THE
AREA ON SATURDAY.... WITH THE LATEST ECMWF GENERALLY DRY ACROSS THE
AREA. FOR NOW WILL TREND TOWARDS A BLEND OF THE PREVIOUS FORECAST
(WHICH WAS WETTER) AND THE GFS/ECMWF. REGARDLESS WE SHOULD SEE
CLOUDY SKIES... WITH BELOW NORMAL TEMPS. EXPECT HIGHS WILL BE IN THE
LOWER TO MID 30S NW TO THE MID 40S SE (POSSIBLY EVEN A BIT WARMER IN
THE FAR SE).
TEMPS WILL REMAIN STEADY TO SLOWLY INCREASING ON SATURDAY
NIGHT/SUNDAY MORNING. THUS... LOWS FOR THIS PERIOD WILL OCCUR AT THE
BEGINNING OF THE NIGHT TIME PERIOD... GENERALLY THE SAME AS
SATURDAYS HIGHS. THE ASSOCIATED COLD FRONT FROM THE AFOREMENTIONED
SYSTEM WILL APPROACH THE REGION FROM THE WEST.... WITH LOW LEVEL
SOUTHER FLOW INCREASING...WITH PERHAPS AN AREAS OF SHOWER DEVELOPING
ALONG AN INVERTED SURFACE TROUGH IN THE COASTAL PLAIN.
SUNDAY AND SUNDAY NIGHT: THE AFOREMENTIONED COLD FRONT IS EXPECTED
TO MOVE ACROSS CENTRAL NC LATE SUNDAY... WITH A GOOD CHANCE OF
SHOWERS. TEMPS SHOULD WARM UP ON SUNDAY IN ADVANCE OF THE FRONT AS
MOST IF NOT ALL OF THE CWA IS EXPECTED TO MAKE IT INTO THE WARM
SECTOR WITH THE MAIN SURFACE LOW PASSING WELL TO THE NORTH OF THE
REGION ACROSS THE GREAT LAKES. HOWEVER... THE RETREATING CAD MAY
HOLD ON ACROSS THE FAR NORTHWEST UP UNTIL CLOSE TO THE TIME OF THE
FRONT MOVING THROUGH (WHICH WOULD THEN SCOUR IT OUT). FOR NOW WILL
SHOW HIGH TEMPS RANGING FROM AROUND 50 NW TO THE MID TO UPPER 60S
SE.
WITH THE 850 MB TROUGH EXPECTED TO SLOWLY MOVE ACROSS THE REGION...
WILL KEEP A LINGERING CHANCE FOR SHOWERS/RAIN IN THE FORECAST FOR
MOST OF THE AREA SUNDAY NIGHT (PRECIP MOVING OUT IN A NW TO SE/E
FASHION). WILL KEEP ALL PRECIP IN THE FORM OF LIQUID THOUGH. LOWS BY
MONDAY MORNING ARE EXPECTED TO BE IN THE LOWER 30S NW TO THE LOWER
40S SE.
MONDAY THROUGH WEDNESDAY: COLD SURFACE HIGH PRESSURE WILL BUILD INTO
THE AREA BEHIND THE FRONT EARLY NEXT WEEK... THEN EXTEND SOUTHWARD
INTO OUR REGION BY MID WEEK AS IT BEGINS TO SHIFT OFF THE NORTHERN
MID-ATLANTIC COAST. MEDIUM RANGE GUIDANCES CONTINUES TO STRUGGLE
WITH POSSIBLE ADDITIONAL ENERGY AMPLIFYING THE LONG WAVE TROUGH
HELPING TO DEVELOP A SURFACE LOW OFF THE SOUTHEAST U.S. COAST AND
PULLING SOME MOISTURE BACK ACROSS THE AREA EARLY NEXT WEEK... WITH
THE ECMWF SHOWING THE POTENTIAL FOR ANOTHER WINTER STORM. FOR NOW
WILL KEEP ANY POPS IN THE LOW CHANCE CATEGORY AND ACROSS THE EASTERN
HALF OF THE AREA GIVEN THE LOW CONFIDENCE. REGARDLESS... TEMPS ARE
EXPECTED TO BE BELOW NORMAL... WITH HIGHS IN THE 30S AND 40S DURING
THIS TIME FRAME... WITH LOWS IN THE 20S TO LOWER 30S.
&&
.AVIATION /12Z THURSDAY THROUGH MONDAY/...
AS OF 630 AM THURSDAY...
PRIMARY AVIATION CONCERN NEXT 24 HRS: BLUSTERY AND GUSTY WINDS FROM
THE NW.
PASSAGE OF AN ARCTIC COLD FRONT THROUGH NC EARLY THIS MORNING
BROUGHT BRISK WINDS FROM THE NORTHWEST... SUSTAINED UP TO 8-15 KTS
WITH PERIODIC GUSTS TO AROUND 20-25 KTS. THESE WINDS HAVE WEAKENING
SOMEWHAT IN THE LAST FEW HOURS... BUT THESE WINDS SHOULD RESUME
AFTER SUNRISE AND PERSIST THROUGH MUCH OF TODAY AS THE COLD AIR
SURGES IN WITH FRIGID HIGH PRESSURE BUILDING IN. WINDS SHOULD START
TO DECREASE SLOWLY AFTER SUNSET THIS EVENING. WE WILL SEE SCT TO BKN
FLAT STRATOCU BASED ABOVE 3500 FT AGL THIS AFTERNOON BETWEEN 17Z AND
22Z... BUT OTHERWISE SKIES WILL BE FAIR TO MOSTLY CLEAR THROUGH THE
NEXT 24 HRS... WITH VFR VSBYS.
LOOKING BEYOND 12Z EARLY FRI MORNING: VFR CONDITIONS AND VERY CHILLY
TEMPS WILL HOLD THROUGH FRI AS HIGH PRESSURE RIDGING SHIFTS OVER THE
REGION. THIS HIGH WILL THEN MOVE OFFSHORE... AND MID CLOUDS WILL
SPREAD IN FROM THE WEST AND THICKEN/LOWER STARTING LATE FRI AHEAD OF
THE NEXT STORM SYSTEM. CLOUD BASES WILL CONTINUE TO LOWER...
REACHING MVFR NEAR MIDNIGHT FRI NIGHT AT INT/GSO AND WELL AFTER
MIDNIGHT FARTHER EAST AT RDU/RWI/FAY. GOOD CHANCE OF MVFR OR IFR
CONDITIONS DOMINATING ALL SITES FROM SUNRISE SAT THROUGH AT LEAST
SAT NIGHT AND POTENTIALLY SUN/SUN NIGHT AS WELL AS THIS STORM SYSTEM
SHIFTS THROUGH THE AREA. LOW LEVEL WIND SHEAR IS POSSIBLE... MAINLY
FROM SAT INTO SUN. VFR CONDITIONS SHOULD RESUME MON EXCEPT PERHAPS
AT FAY WHERE MVFR CONDITIONS MAY HOLD WITH THE FRONT STALLING JUST
TO THE SE. -GIH
&&
.CLIMATE...
THE FOLLOWING ARE RECORD LOW AND LOW MAXIMUM TEMPERATURES FOR
FEBRUARY 19TH...AND 20TH...FOR GSO...RDU...AND FAY...
RECORD LOWS
GSO RDU FAY
FEBRUARY 19: 12 IN 1979 11 IN 1979 8 IN 1958
FEBRUARY 20: 14 IN 1934 13 IN 1979 12 IN 1958
FEBRUARY 21: 13 IN 1959 8 IN 1896 16 IN 1958
RECORD LOW MAXIMUMS
GSO RDU FAY
FEBRUARY 19: 32 IN 1958 31 IN 1903 26 IN 1979
FEBRUARY 20: 29 IN 1947 32 IN 1947 37 IN 1972
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY UNTIL 9 AM EST TODAY FOR NCZ007>011-
021>028-038>043-078.
WIND CHILL ADVISORY UNTIL 9 AM EST FRIDAY FOR NCZ007>011-
021>028-038>043-073>078-083>086-088-089.
&&
$$
SYNOPSIS...HARTFIELD
NEAR TERM...HARTFIELD
SHORT TERM...HARTFIELD
LONG TERM...BSD
AVIATION...HARTFIELD
CLIMATE...WFO RAH
AREA FORECAST DISCUSSION
NWS RALEIGH NC
332 AM EST THU FEB 19 2015
.SYNOPSIS...FRIGID HIGH PRESSURE WILL BUILD OVER THE AREA THROUGH
FRIDAY... BRINGING NEAR RECORD COLD TEMPERATURES AND VERY LOW WIND
CHILLS. ANOTHER STORM SYSTEM WILL APPROACH FROM THE WEST EARLY
SATURDAY... AFFECTING THE REGION OVER THE WEEKEND.
&&
.NEAR TERM /TODAY THROUGH TONIGHT/...
AS OF 235 AM THURSDAY...
...ADVISORY FOR BLACK ICE NORTHERN SECTIONS THIS MORNING AND WIND
CHILL ADVISORY CONTINUES IN EFFECT THROUGH 9 AM FRIDAY...
WILL HOLD ONTO THE WINTER WEATHER ADVISORY FOR BLACK ICE... AS
YESTERDAY`S SNOW SHOWERS COMBINED WITH AREAS WHERE SNOWMELT/ICEMELT
HAS REFROZEN HAS RESULTED IN AREAS OF BLACK ICE.
THE ADVERTISED POLAR AIR SURGE HAS BEGUN WITH 2 AM TEMPS ALREADY
DOWN INTO THE TEENS OVER MUCH OF THE NRN PIEDMONT AND DEWPOINTS WELL
BELOW ZERO. WINDS HAVE PERIODICALLY GUSTED ABOVE 20 MPH AT MANY
LOCATIONS BUT THE STRONGER WINDS AND GUSTS HAVE BEEN VERY ERRATIC SO
FAR... PROBABLY DUE IN PART TO SUBTLE DECOUPLING NOTED ON RAP BUFR
FORECAST SOUNDINGS. AFTER SUNRISE HOWEVER... WE SHOULD BEGIN TO MIX
MORE FULLY UP THROUGH THE LOWEST 3-4 KFT WITH STEADY DEEP COLD AIR
ADVECTION... ALLOWING FOR GREATER MOMENTUM TRANSFER DOWN TO THE
SURFACE. CONSENSUS OF MODEL FORECAST WINDS THROUGH THE MIXED DEPTH
TODAY SUPPORT PERIODIC GUSTS REACHING AS HIGH AS 20 TO 25 MPH...
WITH SUSTAINED WINDS MOSTLY BETWEEN 9 AND 17 MPH. AFTER LOWS THIS
MORNING FROM 10 TO 19 DEGREES... TEMPS SHOULD RISE MINIMALLY TO
HIGHS FROM 16 TO 25... ADHERING CLOSELY TO THE COOLER GFS-BASED
STATISTICAL GUIDANCE WHICH IS SUPPORTED BY YESTERDAY`S HIGHS
UPSTREAM OVER THE WRN OH VALLEY. STILL EXPECT TEMPS TO DROP TO THE 3
BELOW TO 7 ABOVE RANGE FOR LOWS TONIGHT... AGAIN ON THE COOL SIDE OF
GUIDANCE WITHIN THIS ANOMALOUSLY COLD AIR MASS. WIND CHILLS THIS
MORNING SHOULD MOSTLY BE IN THE 5 BELOW TO 8 ABOVE RANGE... RISING
TO 1 ABOVE TO 13 ABOVE THIS AFTERNOON BEFORE DROPPING BACK DOWN
BELOW ZERO AFTER NIGHTFALL... BOTTOMING OUT OVERNIGHT TO BETWEEN 3
BELOW (SOUTH) AND 15 BELOW (NORTH)... DESPITE WIND SPEEDS FALLING
OFF A BIT TONIGHT. THE WIND CHILL ADVISORY WILL BE MAINTAINED AS IS.
WITH SUBSIDENCE AND DRY/STABLE AIR ALOFT... EXPECT MOSTLY CLEAR
SKIES TODAY/TONIGHT... EXCEPT FOR A LIKELY PERIOD OF FLAT BROKEN
CLOUDS THIS AFTERNOON. -GIH
&&
.SHORT TERM /FRIDAY THROUGH FRIDAY NIGHT/...
AS OF 305 AM THURSDAY...
VERY COLD TEMPS PERSIST. WINDS WILL CONTINUE TO DIE DOWN FRI
MORNING... STAYING LIGHT AS THE CENTER OF THE POLAR HIGH SETTLES
OVER THE REGION FRI AFTERNOON/EVENING... THEN SHIFTS ENE OFF THE
COAST FRI NIGHT. THE COLD VORTEX OVER MAINE EARLY FRI SHIFTS TO THE
NE THROUGH FRI NIGHT... RESULTING IN A FLATTENING MID LEVEL FLOW
OVER THE SOUTH-CENTRAL AND SOUTHEAST STATES AND EVENTUALLY
INCREASING DPVA AS HEIGHTS SLOWLY FALL OVER THE SRN PLAINS. AS THE
850 MB ANTICYCLONE MOVES FROM THE GULF FRI MORNING EASTWARD AND OFF
THE SE COAST THROUGH FRI NIGHT... THE INFLUX OF GULF MOISTURE INTO
THE MIDSOUTH AND SOUTHEAST WILL STRENGTHEN... AND CLOUDS WILL
INCREASE FROM WEST TO EAST OVER NC AS MOIST UPGLIDE INITIALLY WELL
ALOFT STARTS TO DEEPEN GROUNDWARD. THERE REMAINS A SUBSTANTIAL DRY
SUBCLOUD LAYER OVER MUCH OF THE CWA INTO FRI NIGHT... AND THIS IS
REFLECTED IN A LACK OF PRECIP OVER ALL BUT PERHAPS THE FAR NW
PORTION OF THE CWA LATE FRI NIGHT. THE NAM IS MUCH FASTER THAN THE
GFS/ECMWF IN BRINGING PRECIP INTO THE NW... AND FOR NOW HAVE
CONTINUED TO LEAN TOWARD A BIT SLOWER AND HENCE DRIER SOLUTION...
WITH JUST A SLIGHT CHANCE POP IN THE NW LATE FRI NIGHT. THE THERMAL
AND MOISTURE STRUCTURE ON FORECAST SOUNDINGS SUPPORT AN INITIAL
PTYPE OF MOSTLY LIGHT SNOW... MIXING WITH A LITTLE LIGHT SLEET...
BUT THESE EARLY HOURS OF PRECIP SHOULD BE QUITE LIGHT. EXPECT HIGHS
IN THE 20S FRI (COOLEST NE) AND LOWS FRI NIGHT OF 11-22 (AGAIN
COOLEST NE). TEMPS SHOULD REACH LOWS EARLY FRI NIGHT THEN LEVEL OFF
OR EVEN RISE A DEGREE OR TWO LATE AS SKIES BECOME OVERCAST. -GIH
&&
.LONG TERM /SATURDAY THROUGH WEDNESDAY/...
AS OF 325 AM THURSDAY...
SATURDAY AND SATURDAY NIGHT: A MODIFIED ARCTIC SURFACE HIGH OVER THE
AREA ON SATURDAY MORNING WILL SHIFT EASTWARD AND OFFSHORE ON
SATURDAY... LEAVING BEHIND A COLD/DRY LOW LEVEL AIRMASS.
MEANWHILE... S/W ENERGY AND AN ASSOCIATED SURFACE LOW OVER THE
SOUTHERN PLAINS ON SATURDAY MORNING WILL LIFT NORTHEASTWARD INTO THE
OHIO VALLEY. BOTH THE ECMWF AND GFS HAVE TREND DRIER OVER CENTRAL
NC... WITH ANY PRECIP DEVELOPING FROM THE WAA OVER THE AREA. AT THIS
TIME THE NORTHWEST PIEDMONT STANDS THE BEST CHANCE OF SEEING SOME
PRECIP. GIVEN THE ANTECEDENT SURFACE AIRMASS EXPECT ANY PRECIP WOULD
START OUT AS SNOW SATURDAY MORNING... THEN TRANSITION TO FREEZING
RAIN AND EVENTUALLY RAIN AS THE SURFACE HIGH CONTINUES TO SHIFT AWAY
FROM THE AREA... RESULTING IN AN INSITU CAD EVENT. CONFIDENCE IS LOW
WITH REGARD TO HOW MUCH PRECIP WE WILL SEE. THUS... HAVE TRIMMED
BACK ON POPS AND WILL ALLOW TEMPS TO WARM UP A BIT QUICKER. THE NAM
IS THE MOST AGGRESSIVE WITH DEVELOPING PRECIP ACROSS MOST OF THE
AREA ON SATURDAY.... WITH THE LATEST ECMWF GENERALLY DRY ACROSS THE
AREA. FOR NOW WILL TREND TOWARDS A BLEND OF THE PREVIOUS FORECAST
(WHICH WAS WETTER) AND THE GFS/ECMWF. REGARDLESS WE SHOULD SEE
CLOUDY SKIES... WITH BELOW NORMAL TEMPS. EXPECT HIGHS WILL BE IN THE
LOWER TO MID 30S NW TO THE MID 40S SE (POSSIBLY EVEN A BIT WARMER IN
THE FAR SE).
TEMPS WILL REMAIN STEADY TO SLOWLY INCREASING ON SATURDAY
NIGHT/SUNDAY MORNING. THUS... LOWS FOR THIS PERIOD WILL OCCUR AT THE
BEGINNING OF THE NIGHT TIME PERIOD... GENERALLY THE SAME AS
SATURDAYS HIGHS. THE ASSOCIATED COLD FRONT FROM THE AFOREMENTIONED
SYSTEM WILL APPROACH THE REGION FROM THE WEST.... WITH LOW LEVEL
SOUTHER FLOW INCREASING...WITH PERHAPS AN AREAS OF SHOWER DEVELOPING
ALONG AN INVERTED SURFACE TROUGH IN THE COASTAL PLAIN.
SUNDAY AND SUNDAY NIGHT: THE AFOREMENTIONED COLD FRONT IS EXPECTED
TO MOVE ACROSS CENTRAL NC LATE SUNDAY... WITH A GOOD CHANCE OF
SHOWERS. TEMPS SHOULD WARM UP ON SUNDAY IN ADVANCE OF THE FRONT AS
MOST IF NOT ALL OF THE CWA IS EXPECTED TO MAKE IT INTO THE WARM
SECTOR WITH THE MAIN SURFACE LOW PASSING WELL TO THE NORTH OF THE
REGION ACROSS THE GREAT LAKES. HOWEVER... THE RETREATING CAD MAY
HOLD ON ACROSS THE FAR NORTHWEST UP UNTIL CLOSE TO THE TIME OF THE
FRONT MOVING THROUGH (WHICH WOULD THEN SCOUR IT OUT). FOR NOW WILL
SHOW HIGH TEMPS RANGING FROM AROUND 50 NW TO THE MID TO UPPER 60S
SE.
WITH THE 850 MB TROUGH EXPECTED TO SLOWLY MOVE ACROSS THE REGION...
WILL KEEP A LINGERING CHANCE FOR SHOWERS/RAIN IN THE FORECAST FOR
MOST OF THE AREA SUNDAY NIGHT (PRECIP MOVING OUT IN A NW TO SE/E
FASHION). WILL KEEP ALL PRECIP IN THE FORM OF LIQUID THOUGH. LOWS BY
MONDAY MORNING ARE EXPECTED TO BE IN THE LOWER 30S NW TO THE LOWER
40S SE.
MONDAY THROUGH WEDNESDAY: COLD SURFACE HIGH PRESSURE WILL BUILD INTO
THE AREA BEHIND THE FRONT EARLY NEXT WEEK... THEN EXTEND SOUTHWARD
INTO OUR REGION BY MID WEEK AS IT BEGINS TO SHIFT OFF THE NORTHERN
MID-ATLANTIC COAST. MEDIUM RANGE GUIDANCES CONTINUES TO STRUGGLE
WITH POSSIBLE ADDITIONAL ENERGY AMPLIFYING THE LONG WAVE TROUGH
HELPING TO DEVELOP A SURFACE LOW OFF THE SOUTHEAST U.S. COAST AND
PULLING SOME MOISTURE BACK ACROSS THE AREA EARLY NEXT WEEK... WITH
THE ECMWF SHOWING THE POTENTIAL FOR ANOTHER WINTER STORM. FOR NOW
WILL KEEP ANY POPS IN THE LOW CHANCE CATEGORY AND ACROSS THE EASTERN
HALF OF THE AREA GIVEN THE LOW CONFIDENCE. REGARDLESS... TEMPS ARE
EXPECTED TO BE BELOW NORMAL... WITH HIGHS IN THE 30S AND 40S DURING
THIS TIME FRAME... WITH LOWS IN THE 20S TO LOWER 30S.
&&
.AVIATION /06Z THURSDAY THROUGH MONDAY/...
AS OF 1225 AM THURSDAY...
PRIMARY AVIATION CONCERN NEXT 24 HRS: BLUSTERY AND GUSTY WINDS FROM
THE NW.
PASSAGE OF AN ARCTIC COLD FRONT THROUGH NC EARLY THIS MORNING IS
BRINGING BRISK WINDS FROM THE NORTHWEST... SUSTAINED UP TO 8-15 KTS
WITH PERIODIC GUSTS TO AROUND 20-25 KTS... AND THESE WINDS SHOULD
PERSIST THROUGH MUCH OF THU AS THE COLD AIR SURGES IN WITH FRIGID
HIGH PRESSURE BUILDING IN. WINDS SHOULD START TO DECREASE SLOWLY
AFTER SUNSET THIS EVENING. WE WILL SEE SCT TO BKN FLAT STRATOCU
BASED ABOVE 3500 FT AGL THIS AFTERNOON BETWEEN 17Z AND 22Z... BUT
OTHERWISE SKIES WILL BE FAIR TO MOSTLY CLEAR THROUGH THE NEXT 24
HRS... WITH VFR VSBYS.
LOOKING BEYOND 06Z EARLY FRI MORNING: VFR CONDITIONS AND VERY CHILLY
TEMPS WILL HOLD THROUGH FRI AS HIGH PRESSURE RIDGING SHIFTS OVER THE
REGION. THIS HIGH WILL THEN MOVE OFFSHORE... AND MID CLOUDS WILL
SPREAD IN FROM THE WEST AND THICKEN/LOWER STARTING LATE FRI AHEAD OF
THE NEXT STORM SYSTEM. CLOUD BASES WILL CONTINUE TO LOWER...
REACHING MVFR NEAR MIDNIGHT FRI NIGHT AT INT/GSO AND WELL AFTER
MIDNIGHT FARTHER EAST AT RDU/RWI/FAY. GOOD CHANCE OF MVFR OR IFR
CONDITIONS DOMINATING ALL SITES FROM SUNRISE SAT THROUGH AT LEAST
SAT NIGHT AND POTENTIALLY SUN/SUN NIGHT AS WELL AS THIS STORM SYSTEM
SHIFTS THROUGH THE AREA. LOW LEVEL WIND SHEAR IS POSSIBLE... MAINLY
FROM SAT INTO SUN. VFR CONDITIONS SHOULD RESUME MON EXCEPT PERHAPS
AT FAY WHERE MVFR CONDITIONS MAY HOLD WITH THE FRONT STALLING JUST
TO THE SE. -GIH
&&
.CLIMATE...
THE FOLLOWING ARE RECORD LOW AND LOW MAXIMUM TEMPERATURES FOR
FEBRUARY 19TH...AND 20TH...FOR GSO...RDU...AND FAY...
RECORD LOWS
GSO RDU FAY
FEBRUARY 19: 12 IN 1979 11 IN 1979 8 IN 1958
FEBRUARY 20: 14 IN 1934 13 IN 1979 12 IN 1958
FEBRUARY 21: 13 IN 1959 8 IN 1896 16 IN 1958
RECORD LOW MAXIMUMS
GSO RDU FAY
FEBRUARY 19: 32 IN 1958 31 IN 1903 26 IN 1979
FEBRUARY 20: 29 IN 1947 32 IN 1947 37 IN 1972
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY UNTIL 9 AM EST TODAY FOR NCZ007>011-
021>028-038>043-078.
WIND CHILL ADVISORY UNTIL 9 AM EST FRIDAY FOR NCZ007>011-
021>028-038>043-073>078-083>086-088-089.
&&
$$
SYNOPSIS...HARTFIELD
NEAR TERM...HARTFIELD
SHORT TERM...HARTFIELD
LONG TERM...BSD
AVIATION...HARTFIELD
CLIMATE...WFO RAH
AREA FORECAST DISCUSSION
NWS RALEIGH NC
305 AM EST THU FEB 19 2015
.SYNOPSIS...FRIGID HIGH PRESSURE WILL BUILD OVER THE AREA THROUGH
FRIDAY... BRINGING NEAR RECORD COLD TEMPERATURES AND VERY LOW WIND
CHILLS. ANOTHER STORM SYSTEM WILL APPROACH FROM THE WEST EARLY
SATURDAY... AFFECTING THE REGION OVER THE WEEKEND.
&&
.NEAR TERM /TODAY THROUGH TONIGHT/...
AS OF 235 AM THURSDAY...
...ADVISORY FOR BLACK ICE NORTHERN SECTIONS THIS MORNING AND WIND
CHILL ADVISORY CONTINUES IN EFFECT THROUGH 9 AM FRIDAY...
WILL HOLD ONTO THE WINTER WEATHER ADVISORY FOR BLACK ICE... AS
YESTERDAY`S SNOW SHOWERS COMBINED WITH AREAS WHERE SNOWMELT/ICEMELT
HAS REFROZEN HAS RESULTED IN AREAS OF BLACK ICE.
THE ADVERTISED POLAR AIR SURGE HAS BEGUN WITH 2 AM TEMPS ALREADY
DOWN INTO THE TEENS OVER MUCH OF THE NRN PIEDMONT AND DEWPOINTS WELL
BELOW ZERO. WINDS HAVE PERIODICALLY GUSTED ABOVE 20 MPH AT MANY
LOCATIONS BUT THE STRONGER WINDS AND GUSTS HAVE BEEN VERY ERRATIC SO
FAR... PROBABLY DUE IN PART TO SUBTLE DECOUPLING NOTED ON RAP BUFR
FORECAST SOUNDINGS. AFTER SUNRISE HOWEVER... WE SHOULD BEGIN TO MIX
MORE FULLY UP THROUGH THE LOWEST 3-4 KFT WITH STEADY DEEP COLD AIR
ADVECTION... ALLOWING FOR GREATER MOMENTUM TRANSFER DOWN TO THE
SURFACE. CONSENSUS OF MODEL FORECAST WINDS THROUGH THE MIXED DEPTH
TODAY SUPPORT PERIODIC GUSTS REACHING AS HIGH AS 20 TO 25 MPH...
WITH SUSTAINED WINDS MOSTLY BETWEEN 9 AND 17 MPH. AFTER LOWS THIS
MORNING FROM 10 TO 19 DEGREES... TEMPS SHOULD RISE MINIMALLY TO
HIGHS FROM 16 TO 25... ADHERING CLOSELY TO THE COOLER GFS-BASED
STATISTICAL GUIDANCE WHICH IS SUPPORTED BY YESTERDAY`S HIGHS
UPSTREAM OVER THE WRN OH VALLEY. STILL EXPECT TEMPS TO DROP TO THE 3
BELOW TO 7 ABOVE RANGE FOR LOWS TONIGHT... AGAIN ON THE COOL SIDE OF
GUIDANCE WITHIN THIS ANOMALOUSLY COLD AIR MASS. WIND CHILLS THIS
MORNING SHOULD MOSTLY BE IN THE 5 BELOW TO 8 ABOVE RANGE... RISING
TO 1 ABOVE TO 13 ABOVE THIS AFTERNOON BEFORE DROPPING BACK DOWN
BELOW ZERO AFTER NIGHTFALL... BOTTOMING OUT OVERNIGHT TO BETWEEN 3
BELOW (SOUTH) AND 15 BELOW (NORTH)... DESPITE WIND SPEEDS FALLING
OFF A BIT TONIGHT. THE WIND CHILL ADVISORY WILL BE MAINTAINED AS IS.
WITH SUBSIDENCE AND DRY/STABLE AIR ALOFT... EXPECT MOSTLY CLEAR
SKIES TODAY/TONIGHT... EXCEPT FOR A LIKELY PERIOD OF FLAT BROKEN
CLOUDS THIS AFTERNOON. -GIH
&&
.SHORT TERM /FRIDAY THROUGH FRIDAY NIGHT/...
AS OF 305 AM THURSDAY...
VERY COLD TEMPS PERSIST. WINDS WILL CONTINUE TO DIE DOWN FRI
MORNING... STAYING LIGHT AS THE CENTER OF THE POLAR HIGH SETTLES
OVER THE REGION FRI AFTERNOON/EVENING... THEN SHIFTS ENE OFF THE
COAST FRI NIGHT. THE COLD VORTEX OVER MAINE EARLY FRI SHIFTS TO THE
NE THROUGH FRI NIGHT... RESULTING IN A FLATTENING MID LEVEL FLOW
OVER THE SOUTH-CENTRAL AND SOUTHEAST STATES AND EVENTUALLY
INCREASING DPVA AS HEIGHTS SLOWLY FALL OVER THE SRN PLAINS. AS THE
850 MB ANTICYCLONE MOVES FROM THE GULF FRI MORNING EASTWARD AND OFF
THE SE COAST THROUGH FRI NIGHT... THE INFLUX OF GULF MOISTURE INTO
THE MIDSOUTH AND SOUTHEAST WILL STRENGTHEN... AND CLOUDS WILL
INCREASE FROM WEST TO EAST OVER NC AS MOIST UPGLIDE INITIALLY WELL
ALOFT STARTS TO DEEPEN GROUNDWARD. THERE REMAINS A SUBSTANTIAL DRY
SUBCLOUD LAYER OVER MUCH OF THE CWA INTO FRI NIGHT... AND THIS IS
REFLECTED IN A LACK OF PRECIP OVER ALL BUT PERHAPS THE FAR NW
PORTION OF THE CWA LATE FRI NIGHT. THE NAM IS MUCH FASTER THAN THE
GFS/ECMWF IN BRINGING PRECIP INTO THE NW... AND FOR NOW HAVE
CONTINUED TO LEAN TOWARD A BIT SLOWER AND HENCE DRIER SOLUTION...
WITH JUST A SLIGHT CHANCE POP IN THE NW LATE FRI NIGHT. THE THERMAL
AND MOISTURE STRUCTURE ON FORECAST SOUNDINGS SUPPORT AN INITIAL
PTYPE OF MOSTLY LIGHT SNOW... MIXING WITH A LITTLE LIGHT SLEET...
BUT THESE EARLY HOURS OF PRECIP SHOULD BE QUITE LIGHT. EXPECT HIGHS
IN THE 20S FRI (COOLEST NE) AND LOWS FRI NIGHT OF 11-22 (AGAIN
COOLEST NE). TEMPS SHOULD REACH LOWS EARLY FRI NIGHT THEN LEVEL OFF
OR EVEN RISE A DEGREE OR TWO LATE AS SKIES BECOME OVERCAST. -GIH
&&
.LONG TERM /SATURDAY THROUGH WEDNESDAY/...
AS OF 400 PM WEDNESDAY...
SAT-SUN NIGHT: LONG RANGE MODEL GUIDANCE (GFS/ECMWF) ARE IN GENERAL
AGREEMENT ON THE SYNOPTIC PATTERN OVER THE WEEKEND. 1035 MB ARCTIC
HIGH PRESSURE CENTERED DIRECTLY OVER CENTRAL NC LATE FRI/FRI NIGHT
WILL GRADUALLY SHIFT OFFSHORE SAT/SAT NIGHT...THOUGH A PRONOUNCED
SFC RIDGE AXIS WILL CONTINUE TO EXTEND INTO THE REGION FROM THE
EAST. MEANWHILE...SHORTWAVE ENERGY DIGGING SOUTHEAST THROUGH THE
ROCKIES INTO THE GREAT PLAINS WILL INITIATE CYCLOGENESIS ALONG A
BAROCLINIC ZONE OVER THE CENTRAL PLAINS...WITH A DEVELOPING WARM
SECTOR OVER THE DEEP SOUTH/SOUTHEAST ADVECTING NORTHWARD INTO THE
CAROLINAS LATE SAT/SAT NIGHT. THE WARM SECTOR WILL BECOME FURTHER
ESTABLISHED OVER THE CAROLINAS ON SUNDAY AS THE AFOREMENTIONED LOW
PRESSURE SYSTEM TRACKS EASTWARD INTO THE OH VALLEY AND MID-ATLANTIC.
THOUGH IN GENERAL AGREEMENT...SUBTLE DIFFERENCES IN THE EVOLUTION OF
THE UPPER LEVEL PATTERN...AND ULTIMATE EVOLUTION OF THE SURFACE LOW
AS IT PROGRESSES EASTWARD INTO THE OH VALLEY/MID-ATLANTIC...ARE
RESULTING IN MAJOR DIFFERENCES BETWEEN THE GFS/ECMWF WITH REGARD TO
PRECIP AMOUNTS AND TIMING SAT/SAT NIGHT. FOR EXAMPLE...ASIDE FROM
0.01 INCHES OR SO IN THE TRIAD SAT MORNING...THE 12Z ECMWF IS
OTHERWISE DRY ON SAT WHILE THE GFS GENERATES OVER A HALF INCH OF
LIQUID EQUIV IN THE NORTHERN PIEDMONT...LARGELY ALONG AND NORTH OF
THE I-85 CORRIDOR. WITH SO MUCH UNCERTAINTY...WILL KEEP PRECIP
CHANCES NO HIGHER THAN 50% SAT/SAT NIGHT. MODEL GUIDANCE IS MORE
FIRMLY IN AGREEMENT ON PRECIP CHANCES ALONG THE COLD FRONT ON
SUNDAY...AND LIKELY PRECIP CHANCES WILL BE INDICATED...TAPERING OFF
FROM WEST-EAST SUN NIGHT.
PTYPE CONCERNS: GIVEN AN ATYPICALLY COLD/BITTER ANTECEDENT AIRMASS
IN PLACE IMMEDIATELY PRIOR TO THE POSSIBLE ONSET OF PRECIP...AND
THAT A SFC RIDGE AXIS WILL LIKELY PERSIST ACROSS THE NORTH/NW
PIEDMONT THROUGH 00Z SUN...ANOTHER ROUND OF SIGNIFICANT WINTER
WEATHER APPEARS LIKELY (ESP ALONG/NORTH OF I-85 TO VA BORDER) AS
LONG AS PRECIPITATION IS PRESENT (I.E. GFS SOLUTION). IF PRECIP
HOLDS OFF UNTIL SAT NIGHT/EARLY SUN AS THE ECMWF SUGGESTS...WARM
ADVECTION WITHIN THE BROAD/EXPANDING WARM SECTOR IN ADVANCE OF THE
DEVELOPING SFC LOW WOULD HAVE SUFFICIENT TIME TO MODIFY THE
ANTECEDENT AIRMASS...SIGNIFICANTLY REDUCING THE POTENTIAL
(CHANCES/AMOUNTS/DURATION) FOR WINTER WX EVERYWHERE ASIDE FROM
PERHAPS A BRIEF POTENTIAL IN THE FAR NW PIEDMONT. EVEN IF PRECIP IS
ASSUMED...ANY STATEMENT ON PRECISE PTYPE(S) OR ACCUM POTENTIAL WOULD
BE LITTLE MORE THAN SPECULATION AT THIS TIME. BROADLY SPEAKING...THE
ANTECEDENT AIRMASS/SYNOPTIC PATTERN AND PRIOR FORECAST EXPERIENCE
ALL SUGGEST FREEZING RAIN /ICE/ AS A PRIMARY HAZARD...PERHAPS
BEGINNING AS SN/PL BEFORE TRANSITIONING TO FZRA IF PRECIP ONSET IS
EARLY ENOUGH SAT MORNING. A TRANSITION TO ALL RAIN FROM SE TO NW
WOULD OCCUR SAT EVENING (BY ~MIDNIGHT SUNDAY MORNING) AS WARM
ADVECTION SATURATES/FURTHER MODIFIES THE AIRMASS ACROSS CENTRAL
NORTH CAROLINA.
MONDAY-WEDNESDAY: BELOW NORMAL TEMPERATURES ASSOCIATED WITH A
MODIFIED ARCTIC AIRMASS ADVECTING INTO THE REGION IN THE WAKE OF A
COLD FRONTAL PASSAGE SUN NIGHT/MON MORNING...I.E. A 1045 MB HIGH IN
THE UPPER MIDWEST (SUN AFTERNOON) BUILDING INTO THE OH VALLEY AT
1035 MB MON/MON NIGHT...THEN WEAKENING ALONG THE NORTHERN MID-
ATLANTIC COAST TUE. -VINCENT
&&
.AVIATION /06Z THURSDAY THROUGH MONDAY/...
AS OF 1225 AM THURSDAY...
PRIMARY AVIATION CONCERN NEXT 24 HRS: BLUSTERY AND GUSTY WINDS FROM
THE NW.
PASSAGE OF AN ARCTIC COLD FRONT THROUGH NC EARLY THIS MORNING IS
BRINGING BRISK WINDS FROM THE NORTHWEST... SUSTAINED UP TO 8-15 KTS
WITH PERIODIC GUSTS TO AROUND 20-25 KTS... AND THESE WINDS SHOULD
PERSIST THROUGH MUCH OF THU AS THE COLD AIR SURGES IN WITH FRIGID
HIGH PRESSURE BUILDING IN. WINDS SHOULD START TO DECREASE SLOWLY
AFTER SUNSET THIS EVENING. WE WILL SEE SCT TO BKN FLAT STRATOCU
BASED ABOVE 3500 FT AGL THIS AFTERNOON BETWEEN 17Z AND 22Z... BUT
OTHERWISE SKIES WILL BE FAIR TO MOSTLY CLEAR THROUGH THE NEXT 24
HRS... WITH VFR VSBYS.
LOOKING BEYOND 06Z EARLY FRI MORNING: VFR CONDITIONS AND VERY CHILLY
TEMPS WILL HOLD THROUGH FRI AS HIGH PRESSURE RIDGING SHIFTS OVER THE
REGION. THIS HIGH WILL THEN MOVE OFFSHORE... AND MID CLOUDS WILL
SPREAD IN FROM THE WEST AND THICKEN/LOWER STARTING LATE FRI AHEAD OF
THE NEXT STORM SYSTEM. CLOUD BASES WILL CONTINUE TO LOWER...
REACHING MVFR NEAR MIDNIGHT FRI NIGHT AT INT/GSO AND WELL AFTER
MIDNIGHT FARTHER EAST AT RDU/RWI/FAY. GOOD CHANCE OF MVFR OR IFR
CONDITIONS DOMINATING ALL SITES FROM SUNRISE SAT THROUGH AT LEAST
SAT NIGHT AND POTENTIALLY SUN/SUN NIGHT AS WELL AS THIS STORM SYSTEM
SHIFTS THROUGH THE AREA. LOW LEVEL WIND SHEAR IS POSSIBLE... MAINLY
FROM SAT INTO SUN. VFR CONDITIONS SHOULD RESUME MON EXCEPT PERHAPS
AT FAY WHERE MVFR CONDITIONS MAY HOLD WITH THE FRONT STALLING JUST
TO THE SE. -GIH
&&
.CLIMATE...
THE FOLLOWING ARE RECORD LOW AND LOW MAXIMUM TEMPERATURES FOR
FEBRUARY 19TH...AND 20TH...FOR GSO...RDU...AND FAY...
RECORD LOWS
GSO RDU FAY
FEBRUARY 19: 12 IN 1979 11 IN 1979 8 IN 1958
FEBRUARY 20: 14 IN 1934 13 IN 1979 12 IN 1958
FEBRUARY 21: 13 IN 1959 8 IN 1896 16 IN 1958
RECORD LOW MAXIMUMS
GSO RDU FAY
FEBRUARY 19: 32 IN 1958 31 IN 1903 26 IN 1979
FEBRUARY 20: 29 IN 1947 32 IN 1947 37 IN 1972
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY UNTIL 9 AM EST TODAY FOR NCZ007>011-
021>028-038>043-078.
WIND CHILL ADVISORY UNTIL 9 AM EST FRIDAY FOR NCZ007>011-
021>028-038>043-073>078-083>086-088-089.
&&
$$
SYNOPSIS...HARTFIELD
NEAR TERM...HARTFIELD
SHORT TERM...HARTFIELD
LONG TERM...VINCENT
AVIATION...HARTFIELD
CLIMATE...WFO RAH
AREA FORECAST DISCUSSION
NWS RALEIGH NC
235 AM EST THU FEB 19 2015
.SYNOPSIS...FRIGID HIGH PRESSURE WILL BUILD OVER THE AREA THROUGH
FRIDAY... BRINGING NEAR RECORD COLD TEMPERATURES AND VERY LOW WIND
CHILLS. ANOTHER STORM SYSTEM WILL APPROACH FROM THE WEST EARLY
SATURDAY... AFFECTING THE REGION OVER THE WEEKEND.
&&
.NEAR TERM /TODAY THROUGH TONIGHT/...
AS OF 235 AM THURSDAY...
...ADVISORY FOR BLACK ICE NORTHERN SECTIONS THIS MORNING AND WIND
CHILL ADVISORY CONTINUES IN EFFECT THROUGH 9 AM FRIDAY...
WILL HOLD ONTO THE WINTER WEATHER ADVISORY FOR BLACK ICE... AS
YESTERDAY`S SNOW SHOWERS COMBINED WITH AREAS WHERE SNOWMELT/ICEMELT
HAS REFROZEN HAS RESULTED IN AREAS OF BLACK ICE.
THE ADVERTISED POLAR AIR SURGE HAS BEGUN WITH 2 AM TEMPS ALREADY
DOWN INTO THE TEENS OVER MUCH OF THE NRN PIEDMONT AND DEWPOINTS WELL
BELOW ZERO. WINDS HAVE PERIODICALLY GUSTED ABOVE 20 MPH AT MANY
LOCATIONS BUT THE STRONGER WINDS AND GUSTS HAVE BEEN VERY ERRATIC SO
FAR... PROBABLY DUE IN PART TO SUBTLE DECOUPLING NOTED ON RAP BUFR
FORECAST SOUNDINGS. AFTER SUNRISE HOWEVER... WE SHOULD BEGIN TO MIX
MORE FULLY UP THROUGH THE LOWEST 3-4 KFT WITH STEADY DEEP COLD AIR
ADVECTION... ALLOWING FOR GREATER MOMENTUM TRANSFER DOWN TO THE
SURFACE. CONSENSUS OF MODEL FORECAST WINDS THROUGH THE MIXED DEPTH
TODAY SUPPORT PERIODIC GUSTS REACHING AS HIGH AS 20 TO 25 MPH...
WITH SUSTAINED WINDS MOSTLY BETWEEN 9 AND 17 MPH. AFTER LOWS THIS
MORNING FROM 10 TO 19 DEGREES... TEMPS SHOULD RISE MINIMALLY TO
HIGHS FROM 16 TO 25... ADHERING CLOSELY TO THE COOLER GFS-BASED
STATISTICAL GUIDANCE WHICH IS SUPPORTED BY YESTERDAY`S HIGHS
UPSTREAM OVER THE WRN OH VALLEY. STILL EXPECT TEMPS TO DROP TO THE 3
BELOW TO 7 ABOVE RANGE FOR LOWS TONIGHT... AGAIN ON THE COOL SIDE OF
GUIDANCE WITHIN THIS ANOMALOUSLY COLD AIR MASS. WIND CHILLS THIS
MORNING SHOULD MOSTLY BE IN THE 5 BELOW TO 8 ABOVE RANGE... RISING
TO 1 ABOVE TO 13 ABOVE THIS AFTERNOON BEFORE DROPPING BACK DOWN
BELOW ZERO AFTER NIGHTFALL... BOTTOMING OUT OVERNIGHT TO BETWEEN 3
BELOW (SOUTH) AND 15 BELOW (NORTH)... DESPITE WIND SPEEDS FALLING
OFF A BIT TONIGHT. THE WIND CHILL ADVISORY WILL BE MAINTAINED AS IS.
WITH SUBSIDENCE AND DRY/STABLE AIR ALOFT... EXPECT MOSTLY CLEAR
SKIES TODAY/TONIGHT... EXCEPT FOR A LIKELY PERIOD OF FLAT BROKEN
CLOUDS THIS AFTERNOON. -GIH
&&
.SHORT TERM /FRIDAY THROUGH FRIDAY NIGHT/...
AS OF 411 PM WEDNESDAY...
FRI/FRI NIGHT: CONTINUED COLD WITH HIGHS IN THE LOWER/MID 20S...LOWS
WARMER THAN PRIOR NIGHTS DUE TO INCREASING CLOUD COVER...RANGING
FROM 10F FAR NE COASTAL PLAIN TO UPPER TEENS SW PIEDMONT. -VINCENT
&&
.LONG TERM /SATURDAY THROUGH WEDNESDAY/...
AS OF 400 PM WEDNESDAY...
SAT-SUN NIGHT: LONG RANGE MODEL GUIDANCE (GFS/ECMWF) ARE IN GENERAL
AGREEMENT ON THE SYNOPTIC PATTERN OVER THE WEEKEND. 1035 MB ARCTIC
HIGH PRESSURE CENTERED DIRECTLY OVER CENTRAL NC LATE FRI/FRI NIGHT
WILL GRADUALLY SHIFT OFFSHORE SAT/SAT NIGHT...THOUGH A PRONOUNCED
SFC RIDGE AXIS WILL CONTINUE TO EXTEND INTO THE REGION FROM THE
EAST. MEANWHILE...SHORTWAVE ENERGY DIGGING SOUTHEAST THROUGH THE
ROCKIES INTO THE GREAT PLAINS WILL INITIATE CYCLOGENESIS ALONG A
BAROCLINIC ZONE OVER THE CENTRAL PLAINS...WITH A DEVELOPING WARM
SECTOR OVER THE DEEP SOUTH/SOUTHEAST ADVECTING NORTHWARD INTO THE
CAROLINAS LATE SAT/SAT NIGHT. THE WARM SECTOR WILL BECOME FURTHER
ESTABLISHED OVER THE CAROLINAS ON SUNDAY AS THE AFOREMENTIONED LOW
PRESSURE SYSTEM TRACKS EASTWARD INTO THE OH VALLEY AND MID-ATLANTIC.
THOUGH IN GENERAL AGREEMENT...SUBTLE DIFFERENCES IN THE EVOLUTION OF
THE UPPER LEVEL PATTERN...AND ULTIMATE EVOLUTION OF THE SURFACE LOW
AS IT PROGRESSES EASTWARD INTO THE OH VALLEY/MID-ATLANTIC...ARE
RESULTING IN MAJOR DIFFERENCES BETWEEN THE GFS/ECMWF WITH REGARD TO
PRECIP AMOUNTS AND TIMING SAT/SAT NIGHT. FOR EXAMPLE...ASIDE FROM
0.01 INCHES OR SO IN THE TRIAD SAT MORNING...THE 12Z ECMWF IS
OTHERWISE DRY ON SAT WHILE THE GFS GENERATES OVER A HALF INCH OF
LIQUID EQUIV IN THE NORTHERN PIEDMONT...LARGELY ALONG AND NORTH OF
THE I-85 CORRIDOR. WITH SO MUCH UNCERTAINTY...WILL KEEP PRECIP
CHANCES NO HIGHER THAN 50% SAT/SAT NIGHT. MODEL GUIDANCE IS MORE
FIRMLY IN AGREEMENT ON PRECIP CHANCES ALONG THE COLD FRONT ON
SUNDAY...AND LIKELY PRECIP CHANCES WILL BE INDICATED...TAPERING OFF
FROM WEST-EAST SUN NIGHT.
PTYPE CONCERNS: GIVEN AN ATYPICALLY COLD/BITTER ANTECEDENT AIRMASS
IN PLACE IMMEDIATELY PRIOR TO THE POSSIBLE ONSET OF PRECIP...AND
THAT A SFC RIDGE AXIS WILL LIKELY PERSIST ACROSS THE NORTH/NW
PIEDMONT THROUGH 00Z SUN...ANOTHER ROUND OF SIGNIFICANT WINTER
WEATHER APPEARS LIKELY (ESP ALONG/NORTH OF I-85 TO VA BORDER) AS
LONG AS PRECIPITATION IS PRESENT (I.E. GFS SOLUTION). IF PRECIP
HOLDS OFF UNTIL SAT NIGHT/EARLY SUN AS THE ECMWF SUGGESTS...WARM
ADVECTION WITHIN THE BROAD/EXPANDING WARM SECTOR IN ADVANCE OF THE
DEVELOPING SFC LOW WOULD HAVE SUFFICIENT TIME TO MODIFY THE
ANTECEDENT AIRMASS...SIGNIFICANTLY REDUCING THE POTENTIAL
(CHANCES/AMOUNTS/DURATION) FOR WINTER WX EVERYWHERE ASIDE FROM
PERHAPS A BRIEF POTENTIAL IN THE FAR NW PIEDMONT. EVEN IF PRECIP IS
ASSUMED...ANY STATEMENT ON PRECISE PTYPE(S) OR ACCUM POTENTIAL WOULD
BE LITTLE MORE THAN SPECULATION AT THIS TIME. BROADLY SPEAKING...THE
ANTECEDENT AIRMASS/SYNOPTIC PATTERN AND PRIOR FORECAST EXPERIENCE
ALL SUGGEST FREEZING RAIN /ICE/ AS A PRIMARY HAZARD...PERHAPS
BEGINNING AS SN/PL BEFORE TRANSITIONING TO FZRA IF PRECIP ONSET IS
EARLY ENOUGH SAT MORNING. A TRANSITION TO ALL RAIN FROM SE TO NW
WOULD OCCUR SAT EVENING (BY ~MIDNIGHT SUNDAY MORNING) AS WARM
ADVECTION SATURATES/FURTHER MODIFIES THE AIRMASS ACROSS CENTRAL
NORTH CAROLINA.
MONDAY-WEDNESDAY: BELOW NORMAL TEMPERATURES ASSOCIATED WITH A
MODIFIED ARCTIC AIRMASS ADVECTING INTO THE REGION IN THE WAKE OF A
COLD FRONTAL PASSAGE SUN NIGHT/MON MORNING...I.E. A 1045 MB HIGH IN
THE UPPER MIDWEST (SUN AFTERNOON) BUILDING INTO THE OH VALLEY AT
1035 MB MON/MON NIGHT...THEN WEAKENING ALONG THE NORTHERN MID-
ATLANTIC COAST TUE. -VINCENT
&&
.AVIATION /06Z THURSDAY THROUGH MONDAY/...
AS OF 1225 AM THURSDAY...
PRIMARY AVIATION CONCERN NEXT 24 HRS: BLUSTERY AND GUSTY WINDS FROM
THE NW.
PASSAGE OF AN ARCTIC COLD FRONT THROUGH NC EARLY THIS MORNING IS
BRINGING BRISK WINDS FROM THE NORTHWEST... SUSTAINED UP TO 8-15 KTS
WITH PERIODIC GUSTS TO AROUND 20-25 KTS... AND THESE WINDS SHOULD
PERSIST THROUGH MUCH OF THU AS THE COLD AIR SURGES IN WITH FRIGID
HIGH PRESSURE BUILDING IN. WINDS SHOULD START TO DECREASE SLOWLY
AFTER SUNSET THIS EVENING. WE WILL SEE SCT TO BKN FLAT STRATOCU
BASED ABOVE 3500 FT AGL THIS AFTERNOON BETWEEN 17Z AND 22Z... BUT
OTHERWISE SKIES WILL BE FAIR TO MOSTLY CLEAR THROUGH THE NEXT 24
HRS... WITH VFR VSBYS.
LOOKING BEYOND 06Z EARLY FRI MORNING: VFR CONDITIONS AND VERY CHILLY
TEMPS WILL HOLD THROUGH FRI AS HIGH PRESSURE RIDGING SHIFTS OVER THE
REGION. THIS HIGH WILL THEN MOVE OFFSHORE... AND MID CLOUDS WILL
SPREAD IN FROM THE WEST AND THICKEN/LOWER STARTING LATE FRI AHEAD OF
THE NEXT STORM SYSTEM. CLOUD BASES WILL CONTINUE TO LOWER...
REACHING MVFR NEAR MIDNIGHT FRI NIGHT AT INT/GSO AND WELL AFTER
MIDNIGHT FARTHER EAST AT RDU/RWI/FAY. GOOD CHANCE OF MVFR OR IFR
CONDITIONS DOMINATING ALL SITES FROM SUNRISE SAT THROUGH AT LEAST
SAT NIGHT AND POTENTIALLY SUN/SUN NIGHT AS WELL AS THIS STORM SYSTEM
SHIFTS THROUGH THE AREA. LOW LEVEL WIND SHEAR IS POSSIBLE... MAINLY
FROM SAT INTO SUN. VFR CONDITIONS SHOULD RESUME MON EXCEPT PERHAPS
AT FAY WHERE MVFR CONDITIONS MAY HOLD WITH THE FRONT STALLING JUST
TO THE SE. -GIH
&&
.CLIMATE...
THE FOLLOWING ARE RECORD LOW AND LOW MAXIMUM TEMPERATURES FOR
FEBRUARY 19TH...AND 20TH...FOR GSO...RDU...AND FAY...
RECORD LOWS
GSO RDU FAY
FEBRUARY 19: 12 IN 1979 11 IN 1979 8 IN 1958
FEBRUARY 20: 14 IN 1934 13 IN 1979 12 IN 1958
FEBRUARY 21: 13 IN 1959 8 IN 1896 16 IN 1958
RECORD LOW MAXIMUMS
GSO RDU FAY
FEBRUARY 19: 32 IN 1958 31 IN 1903 26 IN 1979
FEBRUARY 20: 29 IN 1947 32 IN 1947 37 IN 1972
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY UNTIL 9 AM EST TODAY FOR NCZ007>011-
021>028-038>043-078.
WIND CHILL ADVISORY UNTIL 9 AM EST FRIDAY FOR NCZ007>011-
021>028-038>043-073>078-083>086-088-089.
&&
$$
SYNOPSIS...HARTFIELD
NEAR TERM...HARTFIELD
SHORT TERM...VINCENT
LONG TERM...VINCENT
AVIATION...HARTFIELD
CLIMATE...WFO RAH
AREA FORECAST DISCUSSION
NWS GRAND FORKS ND
709 PM CST FRI FEB 20 2015
.UPDATE...
ISSUED AT 705 PM CST FRI FEB 20 2015
SHORT WAVE AND SOME LIGHT SNOW SPREADING SOUTH-SOUTHEAST THRU
CNTRL ND ATTM AND SOME OF THIS WILL BRUSH FAR WRN FCST AREA SO
RAISED POPS JUST A LITTLE DVL-VALLEY CITY AREA. OTHERWISE GOT A
FEW FLURRIES AROUND. HARDEST PART IS SKY COVER AND CLEARING TRENDS
FROM THE NORTH. CLEARNING IS WORKING INTO FAR NE ND ATTM FROM
MANITOBA AND LATEST RAP MODEL SUGGEST CLEARING PUSH SOUTH TOWARD
GFK-TVF OVERNIGHT. SATELLITE OF LITTLE HELP AS SOME HIGH AND MID
CLOUDS OVER THE STRATOCU. BID DID REDUCE SKY A BIT TO ACCOUNT FOR
SOME CLEARING OVERNIGHT IN THE NRN VALLEY. TEMPS LOOKED OK.
&&
.SHORT TERM...(THIS EVENING THROUGH SATURDAY NIGHT)
ISSUED AT 250 PM CST FRI FEB 20 2015
THE MAIN CHALLENGE WILL BE BITTERLY COLD AIR BEHIND THE ARCTIC
FRONT TONIGHT THROUGH THE WEEKEND. WE WILL ISSUE THE WIND CHILL
ADVISORY FOR THE NORTH STARTING 9Z SAT-18Z SUN...AND IN THE SOUTH
21Z SAT-18Z SUN.
FOR TONIGHT...THE COLD FRONT WILL USHER IN MUCH COLDER AIR WITH
SOME SNOW SHOWERS FOR ALL AREAS. THERE COULD BE SOME CLEARING IN
THE NORTH LATE...AND WIND CHILLS WILL FALL INTO THE 25 TO 30 BELOW
RANGE LATE IN THE NORTH.
ON SAT...TEMPERATURES MAY FALL IN THE SOUTH AND SHOULD REMAIN
BELOW ZERO NORTH. THERE WILL BE STRONG LOW LEVEL CAA ALONG WITH
ABOUT 25KT TO MIX...PRODUCING DANGEROUS WIND CHILLS AROUND 30
BELOW NORTH TO 25 BELOW SOUTH BY LATE IN THE DAY. THERE COULD BE
SOME FLURRIES OR EVEN SNOW SHOWER STREAMERS AND PERHAPS SOME
DRIFTING OR MINOR BLOWING SNOW IN THE AFTERNOON IN OPEN AREAS.
FOR SAT NIGHT...DANGEROUS WIND CHILLS FROM 30 TO 40 BELOW ARE
EXPECTED WITH BITTERLY COLD AIR WITH 925MB TEMPS DOWN TO -33C IN
THE NORTHEAST. IF WINDS REMAIN HIGH ENOUGH...THEN WE COULD GET
INTO THE 45 BELOW RANGE...AND THE POTENTIAL FOR A WIND CHILL
WARNING IS POSSIBLE (40 BELOW AND COLDER).
.LONG TERM...(SUNDAY THROUGH FRIDAY)
ISSUED AT 250 PM CST FRI FEB 20 2015
ON SUNDAY...BITTERLY COLD DAY WITH HIGHS BELOW ZERO AND DANGEROUS
WIND CHILLS CONTINUING.
FOR SUNDAY NIGHT AND MONDAY...WIND WILL SHIFT TO THE WEST AND
INCREASE WITH THE THREAT FOR DANGEROUS WIND CHILLS AT LEAST INTO
MONDAY MORNING. THERE COULD BE A BAND OF LIGHT SNOW MONDAY
AFTERNOON IN THE NORTHEAST WITH MUCH WARMER SFC AIR IN THE 20S
MOVING IN...ALTHOUGH IT WILL BE WINDY FROM THE W/SW.
MONDAY NIGHT THROUGH THURSDAY...A GENERAL NW FLOW ALOFT REGIME IS
EXPECTED TO START THE EXTENDED PERIOD. HOWEVER...A WAVE FORECAST TO
CROSS THE REGION MONDAY NIGHT INTO TUES WILL BRING A CHANCE FOR SOME
LIGHT PCPN...ALONG WITH WARMER TEMPS AHEAD OF THE FRONT AS THICKNESS
VALUES INCREASE. OTHERWISE...STRONG COLD ADVECTION LOOKS TO PUSH
DOWN OUT OF CANADA BEHIND THE FRONT. TEMPS LOOK TO DROP AGAIN TO
BELOW NORMAL VALUES...WITH A SECONDARY SHOT OF COLDER AIR EXPECTED
BY WED NIGHT. THE COLDER TEMPS WILL PERSIST THRU THE END OF THE
PERIOD...WITH OCCASIONAL LIGHT PCPN EXPECTED.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z SATURDAY EVENING)
ISSUED AT 705 PM CST FRI FEB 20 2015
BIGGEST ISSUE IS TIMING OF CLEARING OF MVFR STRATOCU CLOUDS. OBS
INDICATE NOT A SOLID OVERCAST AS SOME AREAS SCT MVFR AND OTHERS
OVERCAST MVFR DECK IN THAT 2500 FT AGL RANGE. SOME HIGH AND MID
LEVEL MOISTURE OVER TOP OF AREA DUE TO SHORT WAVE TO OUR WEST.
GENERAL IDEA IS FOR SOME CLEARING WORK SOUTH OVERNIGHT INTO
SATURDAY...TIMING AT EACH INDIVIDUAL SITE IS IN QUESTION AND WILL
BE MONITORED. NORTH-NORTHWEST WINDS 10-15 KTS THRU SATURDAY AFTN.
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...WIND CHILL ADVISORY FROM 3 PM SATURDAY TO NOON CST SUNDAY FOR
NDZ038-039-049-052-053.
WIND CHILL ADVISORY FROM 3 AM SATURDAY TO NOON CST SUNDAY FOR
NDZ006>008-014>016-024-026>030-054.
MN...WIND CHILL ADVISORY FROM 3 PM SATURDAY TO NOON CST SUNDAY FOR
MNZ002-003-017-022>024-027>032-040.
WIND CHILL ADVISORY FROM 3 AM SATURDAY TO NOON CST SUNDAY FOR
MNZ001-004>009-013>016.
&&
$$
UPDATE...RIDDLE
SHORT TERM...DK
LONG TERM...HOPKINS/DK
AVIATION...RIDDLE
AREA FORECAST DISCUSSION
NWS NORMAN OK
912 PM CST FRI FEB 20 2015
.UPDATE...
ADJUSTED WEATHER THROUGH 06Z... TEMPS THROUGH 12Z.
&&
.DISCUSSION...
RELAXING WINDS AHEAD OF THE FRONT HAVE ALLOWED FOR SOME FOG
DEVELOPMENT... ALONG WITH SOME PATCHY AREAS OF DENSE FOG. THIS
SHOULD CLEAR OUT THROUGH 06-07Z AS THE FRONT CONTINUES TO PUSH IN
FROM THE NORTH. 03Z SFC ANALYSIS SHOWS THE FRONT ON THE MOVE...
PUSHING WELL INTO NW OK FROM WOODWARD UP TO JUST NORTH OF PONCA
CITY.
TEMPERATURES HAVE COOLED A TAD FASTER THAN PREVIOUSLY THOUGHT
ACROSS SRN OK AND WRN N TX. ADJUSTED TEMP TREND... WITH THE HRRR
AND RAP DOING A DECENT JOB CAPTURING THE CURRENT TREND THROUGH THE
OVERNIGHT AS THE FRONT PUSHES TOWARDS THE RED RIVER THROUGH
SUNRISE.
JTK
&&
.PREV DISCUSSION... /ISSUED 546 PM CST FRI FEB 20 2015/
AVIATION...
21/00Z TAFS...MVFR/IFR CONDITIONS EXPECTED FIRST HALF OF FORECAST
PERIOD KOKC UP TO KPNC TERMINALS. KOKC/KOUN ON THE EDGE OF
CLEARING LINE AND MAY CLEAR OUT FOR A FEW HOURS THIS EVENING. HIGH
CONFIDENCE THAT KPNC WILL STAY UNDER LOW CIGS UNTIL FRONTAL
BOUNDARY PUSHES THROUGH TONIGHT. CLEARED OUT TERMINALS WESTERN
OKLAHOMA AND KSPS EXPECTED TO SEE MVFR CIGS RETURN FOR FOUR TO SIX
HOURS BEFORE DRIER POST FRONTAL AIR ATTEMPTS TO MIX OUT STRATUS.
STRONG NORTHERLY WINDS EXPECTED AFTER TONIGHTS FROPA WITH VFR
CONDITIONS DOMINATING DAYTIME HOURS TOMORROW.
PREV DISCUSSION... /ISSUED 317 PM CST FRI FEB 20 2015/
DISCUSSION...
LOW CLOUDS AND AREAS OF FOG HAVE ERODED IN PARTS OF WESTERN
OKLAHOMA AND NORTH TEXAS THIS AFTERNOON. MEANWHILE...LOW CLOUDS
REMAIN IN CENTRAL AND EASTERN OKLAHOMA WITH SOME INDICATION OF
LIGHT DRIZZLE FORMING. EXPECT LOW CLOUDS WILL SPREAD BACK INTO
PARTS OF WESTERN OKLAHOMA AND NORTH TEXAS LATER TONIGHT WITH
BETTER CHANCES OF DRIZZLE/LIGHT RAIN SHOWERS ALONG AND EAST
OF I-35. STILL APPEARS THE BEST CHANCE FOR ELEVATED STORMS THIS
EVENING AND OVERNIGHT WILL BE NORTH AND EAST OF THE FA.
MOST OF THE DAYLIGHT HOURS SATURDAY WILL BE DRY WITH COLD AIR
ADVECTION WEAKENING DURING THE AFTERNOON. A STRONGER SURGE OF
COLD AIR WILL OVERSPREAD OKLAHOMA AND TEXAS SATURDAY NIGHT INTO
SUNDAY. AS THIS OCCURS...INCREASING MID AND UPPER LEVEL FORCING
WILL RESULT IN SOME SNOW...ESPECIALLY NORTH AND WEST OF THE FA.
HOWEVER...THE NORTHERN HALF OF OKLAHOMA MAY SEE SOME SNOW WITH THE
BEST CHANCE OF ACCUMULATING SNOW IN NORTHWEST OKLAHOMA.
ANOTHER CHANCE FOR ACCUMULATING SNOW IS EXPECTED SUNDAY AFTERNOON
INTO MONDAY. AT THIS TIME...SOUTHERN OKLAHOMA AND WESTERN NORTH
TEXAS APPEAR TO HAVE THE BEST OPPORTUNITY FOR ACCUMULATING SNOW
WITH SOME SLEET.
BY MONDAY EVENING/EARLY TUESDAY MOST OF THE PRECIPITATION WILL
END AS A MID/UPPER LEVEL SYSTEM MOVES EAST.
ANOTHER ROUND OF RATHER COLD AIR IS EXPECTED THURSDAY INTO FRIDAY
OF NEXT WEEK. SOME WINTER PRECIPITATION IS POSSIBLE.
&&
.PRELIMINARY POINT TEMPS/POPS...
OKLAHOMA CITY OK 38 54 27 33 / 20 10 20 30
HOBART OK 40 54 27 33 / 0 0 10 20
WICHITA FALLS TX 44 59 32 38 / 0 0 10 30
GAGE OK 34 48 21 26 / 10 10 60 50
PONCA CITY OK 34 50 22 28 / 40 10 20 40
DURANT OK 48 61 35 41 / 30 20 10 50
&&
.OUN WATCHES/WARNINGS/ADVISORIES...
OK...NONE.
TX...NONE.
&&
$$
04/11
AREA FORECAST DISCUSSION...UPDATED
NWS MILWAUKEE/SULLIVAN WI
928 AM CST THU FEB 19 2015
.UPDATE...
QUIET CONDITIONS BUT VERY COLD AIR WILL STICK AROUND DURING THE
AFTERNOON TODAY. ARCTIC HIGH PRESSURE AND SUBSIDENCE...COUPLED
WITH DRY LOW LEVEL AIR SHOULD KEEP SKIES MOSTLY CLEAR THURSDAY.
WIND CHILL VALUES WILL REMAIN IN THE NEGATIVE TEENS AND SINGLE
DIGITS THIS AFTERNOON...BUT ABOVE WIND CHILL ADVISORY CRITERIA.
RAP BUFKIT SOUNDINGS SHOW STEEPENING LOW LEVEL LAPSE RATES THIS
AFTERNOON...BUT WITH THE SUBSIDENCE IN PLACE ALONG WITH THE DRY
LOW LEVEL AIR...FLURRIES DON/T APPEAR LIKELY.
&&
.AVIATION/18Z TAFS/...
VFR CONDITIONS THIS AFTERNOON AS ARCTIC HIGH PRESSURE...COUPLED
WITH ATMOSPHERIC SUBSIDENCE...WILL KEEP CONDITIONS QUIET AND SKIES
MOSTLY CLEAR. WHILE RAP BUFKIT SOUNDINGS INDICATE STEEPENING LOW
LEVEL LAPSE RATES...THE SUBSIDENCE IN PLACE ALONG WITH VERY DRY
LOW LEVELS INDICATE FLURRIES ARE NOT LIKELY.
&&
.PREV DISCUSSION... /ISSUED 337 AM CST THU FEB 19 2015/
SHORT TERM...
TODAY...FORECAST CONFIDENCE HIGH
SURFACE WINDS HAVE EASED UNDER 10 KNOTS WITH VERY SHALLOW NEAR-
SURFACE INVERSION DEVELOPING UNDER CLEAR SKIES. WIND CHILLS OF -20
TO -25 STILL PREVALENT ACROSS THE FORECAST AREA AND NOT EXPECTED TO
RISE ABOVE -20 BEFORE 16Z IN THE WEST AND 18Z IN THE EAST...WHERE
WINDS WILL BE A BIT HIGHER. NO CHANGE TO END TIME OF ADVISORY FOR NOW
..BUT WILL MONITOR TRENDS FOR POSSIBLE EARLY CANCELLATION IN THE
WEST AS WINDS WILL REMAIN LIGHT AS RIDGE OF HIGH PRESSURE PASSES
THROUGH. 925 MB TEMPS DO NOT MODIFY UPWARD UNTIL LATE
AFTERNOON/EVENING SO HIGHS IN THE SINGLE DIGITS ABOVE FROM PREVIOUS
FORECAST STILL ON TRACK.
TONIGHT...FORECAST CONFIDENCE HIGH
WINDS CHILL ADVISORIES WILL PROBABLY BE NEEDED AGAIN TONIGHT...BUT
COMBINATION OF EXPECTED LIGHT WINDS AND TEMPS NOT FALLING OFF AS
MUCH IN THE WEST AS IN THE EAST WILL LIMIT POTENTIAL OF -20 VALUES
ALONG AND SW OF A DELLS...MADISON TO JANESVILLE LINE. NEXT SHIFT CAN
ASSESS WITH UPDATED MODEL GUIDANCE AND HOME IN ON EXACT LOCATIONS
BUT ADVISORIES LOOK LIKELY TO THE NORTHWEST OF THE ABOVE LINE.
ISENTROPIC LIFT/LAYER Q-VECTOR CONVERGENCE AND ISENTROPIC FORECASTS
ALL SUPPORT MODEL QPF FIELDS THAT HOLD WARM AIR ADVECTION SNOW OFF
TO THE WEST OF THE CWA THROUGH 12Z FRIDAY.
FRIDAY THROUGH SATURDAY... FORECAST CONFIDENCE MEDIUM.
DRY AND COLD SURFACE HIGH PRESSURE WILL DEPART THE UPPER GREAT LAKES
AREA BY FRIDAY MORNING. NORTHWEST FLOW ALOFT AND A SURFACE LOW
PRESSURE TROUGH SLIDING INTO THE NORTHERN PLAINS WILL LEAD TO BRISK
SOUTHERLY WINDS ACROSS WISCONSIN. WARM AIR ADVECTION... ISENTROPIC
LIFT...INCREASING MOISTURE... WEAK Q-VECTOR CONVERGENCE AND A
SHORTWAVE WILL LEAD TO LIGHT SNOW SPREADING ACROSS SOUTHERN WI
MAINLY IN THE AFTERNOON AND EVENING. SNOW AMOUNTS WILL BE LIGHT...
UP TO 1.5 INCHES TOWARD CENTRAL WI. THE COLD TEMPS WILL BE MODERATED
TO THE UPPER TEENS ON FRIDAY AND UPPER 20S SATURDAY.
ON SATURDAY... A 500MB SHORTWAVE TROUGH AND COUPLED UPPER JET
STRUCTURE WILL HELP DEVELOP A STRONG SURFACE LOW PRESSURE SYSTEM
WITH A LOT OF MOISTURE OVER THE SOUTH CENTRAL STATES. THIS SYSTEM IS
EXPECTED TO TRACK INTO THE NORTHEAST U.S. AND BARELY BRUSH SOUTHEAST
WISCONSIN. THE 00Z ECMWF AND CANADIAN MODELS ARE FURTHEST NORTH WITH
THE SNOW PRECIP SHIELD NOW WHILE THE NAM AND GFS KEEP SOUTHEAST WI
DRY. WE WILL CONTINUE TO KEEP AN EYE ON THIS SYSTEM TO SEE IF ITS
NORTHWARD TREND CONTINUES.
LONG TERM...
SUNDAY AND MONDAY...FORECAST CONFIDENCE HIGH.
ANOTHER SURGE OF ARCTIC AIR WILL DROP INTO SOUTHERN WI ON SUNDAY
NIGHT BEHIND THIS DEPARTING SYSTEM. SURFACE HIGH PRESSURE WILL DRIFT
ACROSS THE UPPER MIDWEST ON SUNDAY AND MONDAY. HIGHS ARE EXPECTED IN
THE LOWER TEENS THESE DAYS. LOWS WILL DIP BACK INTO THE SINGLE
DIGITS BELOW ZERO SUNDAY NIGHT.
TUESDAY AND WEDNESDAY... FORECAST CONFIDENCE MEDIUM.
A LOW PRESSURE TROUGH DROPPING SOUTHEAST THROUGH THE UPPER GREAT
LAKES MAY BRING ANOTHER ROUND OF LIGHT SNOW MONDAY NIGHT INTO
TUESDAY. TEMPS ON TUESDAY ARE EXPECTED TO RISE INTO THE 20S WITH THE
WEAK WARM AIR ADVECTION ASSOCIATED WITH THIS SYSTEM.
ARCTIC AIR WILL SURGE BACK INTO SOUTHERN WISCONSIN WEDNESDAY MORNING
AS ANOTHER MID LEVEL SHORTWAVE TROUGH DIVES INTO THE REGION. THIS
COLD DRY AIR IS EXPECTED TO HANG AROUND THROUGH THE END OF NEXT WEEK.
AVIATION/12Z TAFS/...
WINDS EASED WITH NEAR-SURFACE INVERSION DEVELOPING UNDER CLEAR
SKIES...AND WINDS WILL NOT JUMP UP MUCH AFTER DAYBREAK AS GRADIENT
WILL CONTINUE TO WEAKEN WITH RIDGE OF HIGH PRESSURE BUILDING IN.
GENERALLY CLEAR SKIES...THOUGH STEEP LOW-LEVEL LAPSE RATES AGAIN
BRING THE POTENTIAL OF SCATTERED STRATO CU DEVELOPMENT THIS
AFTERNOON...THOUGH CHANCE OF BROKEN MVFR LESS THAN YESTERDAY. WILL
SEE AN INCREASE OF HI LEVEL CLOUDS TOWARDS THE END OF THE FORECAST
PERIOD AS WARM AIR PUSHES IN AHEAD OF NEXT TROUGH. KEEPING SNOW OUT
OF TAF SITES THROUGH 12Z FRIDAY...WITH KMKE NOT EXPECTED TO SEE SNOW
UNTIL AFTER 18Z.
MARINE...
A SMALL CRAFT ADVISORY MAY BE NEEDED FRIDAY INTO FRIDAY NIGHT AS
SOUTHERLY WINDS INCREASE TO NEAR ADVISORY LEVELS AHEAD OF AN
APPROACHING TROUGH OF LOW PRESSURE.
&&
.MKX WATCHES/WARNINGS/ADVISORIES...
WI...WIND CHILL ADVISORY UNTIL NOON CST TODAY FOR WIZ046-047-051-052-
056>060-062>072.
LM...NONE.
&&
$$
UPDATE...JTS
TODAY/TONIGHT AND AVIATION/MARINE...REM
FRIDAY THROUGH WEDNESDAY...MRC
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 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...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
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 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 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 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 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 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
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 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 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 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 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...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 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 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 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 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
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