Forecast Discussions mentioning any of
"HRRR" "RAP" "RR" "RUC13" "RUC" received at GSD on 02/19/15
AREA FORECAST DISCUSSION
NWS ALBANY NY
1035 PM EST WED FEB 18 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 /THROUGH THURSDAY/...
WARM AIR ADVECTION SNOW HAS DEVELOPED ACROSS THE AREA AHEAD OF AN
APPROACHING LOW PRESSURE SYSTEM WITH A LINE OF SNOW SQUALLS
CONTINUING TO MOVE ACROSS CENTRAL NEW YORK JUST AHEAD OF THE COLD
FRONT. THE HRRR CONTUNUES TO INDICATE THE SNOW SQUALLS WILL WEAKEN
AS THE MOVE EASTWARD INTO EAST CENTRAL NEW YORK. SNOWFALL AMOUNTS
WITH OVERNIGHT ARE EXPECTED TO GENERALLY BE A COATING TO AN INCH
WITH 1 TO 2 INCHES ACROSS WESTERN ADIRONDACKS AND WESTERN MOHAWK
VALLEY.
DUE TO CLOUDS AND A WEAK SOUTHERLY FLOW OVERNIGHT TEMPERATURES
WILL NOT BE AS FRIGID AS LAST NIGHT WITH LOWS GENERALLY 5 TO 10
ABOVE...WITH SOME NEAR ZERO READINGS IN THE ADIRONDACKS.
&&
.SHORT TERM /THURSDAY NIGHT THROUGH FRIDAY NIGHT/...
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.
WIDESPREAD SNOW SHOWERS WILL BE ONGOING THURSDAY MORNING...BUT
WILL BE TAPERING OFF BY MIDDAY FOR MOST AREAS...AS THE FRONT
CONTINUES TO PUSH EASTWARD...AND THE WAVE ON THE BOUNDARY RE-
DEVELOPS AND RAPIDLY STRENGTHENS OFF THE EASTERN NEW ENGLAND
COAST. TEMPS WON/T RISE TOO MUCH ON THURSDAY WITH THE STRONG COLD
AIR ADVECTION IN PLACE...AS 850 HPA TEMPS FALL TO -20 TO -25
DEGREES C. HIGHS WILL ONLY REACH THE SINGLE DIGITS TO MID TEENS.
SOME ADDITIONAL UPSLOPE SNOW MAY OCCUR WITH IN THE NW FLOW FOR
THE HIGH TERRAIN AREAS OF WESTERN NEW ENGLAND...AND SOME LAKE
ENHANCED SNOW SHOWERS COULD ALSO BE OCCURRING INTO THE MOHAWK
VALLEY/SCHOHARIE COUNTY THANKS TO THE FLOW MOVING ACROSS LAKE
ONTARIO. SOME ADDITIONAL ACCUMULATION OF AN INCH OR TWO IS
POSSIBLE FOR THESE AREAS.
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 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 /04Z THURSDAY THROUGH MONDAY/...
SNOW WAS DEVELOPING ACROSS THE REGION AHEAD OF AN APPROACHING LOW
PRESSURE SYSTEM...WITH A LINE OF SNOW SQUALLS OCCURRING ACROSS
CENTRAL NEW YORK AND PENNSYLVANIA JUST AHEAD OF THE COLD FRONT.
THE HRRR INDICATES THE SNOW SQUALLS WILL WEAKEN AS THE MOVE
EASTWARD INTO EAST CENTRAL NEW YORK. DO EXPECT SNOW/SNOW SHOWERS
TO DEVELOP ACROSS THE FORECAST AREA TONIGHT WITH CLOUDS LOWERING.
VFR CONDITIONS WILL LOWER TO MVFR WITH THE SNOW. AN IMPROVEMENT
BACK TO VFR IS EXPECTED BY MID MORNING THURSDAY. CLOUDS ARE
EXPECTED TO DOMINATE THROUGH THE DAY.
WIND WILL BE LIGHT/VARIABLE TO SOUTHERLY OVERNIGHT. THEY WILL
SHIFT TO THE WEST AND INCREASING IN SPEED WITH THE PASSAGE OF THE
SYSTEM. AS THE SYSTEM DEEPENS THURSDAY 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...IAA/FRUGIS/HWJIV
SHORT TERM...HWJIV
LONG TERM...IRL
AVIATION...IAA
HYDROLOGY...FRUGIS/HWJIV
AREA FORECAST DISCUSSION
NWS ALBANY NY
753 PM EST WED FEB 18 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 THURSDAY/...
SNOW WAS DEVELOPING ACROSS THE REGION AHEAD OF AN APPROACHING LOW
PRESSURE SYSTEM...WITH A LINE OF SNOW SQUALLS OCCURRING ACROSS
CENTRAL NEW YORK AND PENNSYLVANIA JUST AHEAD OF THE COLD FRONT.
THE HRRR INDICATES THE SNOW SQUALLS WILL WEAKEN AS THE MOVE
EASTWARD INTO EAST CENTRAL NEW YORK. DO EXPECT SNOW/SNOW SHOWERS
TO SPREAD ACROSS THE FORECAST AREA WITH CLOUDS LOWERING.
SNOWFALL AMOUNTS WITH THIS INITIAL SURGE OVERNIGHT ARE EXPECTED TO
GENERALLY BE A COATING TO AN INCH WITH 1 TO 2 INCHES ACROSS
WESTERN ADIRONDACKS AND WESTERN MOHAWK VALLEY.
DUE TO CLOUDS AND A WEAK SOUTHERLY FLOW OVERNIGHT TEMPERATURES
WILL NOT BE AS FRIGID AS LAST NIGHT WITH LOWS GENERALLY 5 TO 10
ABOVE...WITH SOME NEAR ZERO READINGS IN THE ADIRONDACKS.
&&
.SHORT TERM /THURSDAY NIGHT THROUGH FRIDAY NIGHT/...
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.
WIDESPREAD SNOW SHOWERS WILL BE ONGOING THURSDAY MORNING...BUT
WILL BE TAPERING OFF BY MIDDAY FOR MOST AREAS...AS THE FRONT
CONTINUES TO PUSH EASTWARD...AND THE WAVE ON THE BOUNDARY RE-
DEVELOPS AND RAPIDLY STRENGTHENS OFF THE EASTERN NEW ENGLAND
COAST. TEMPS WON/T RISE TOO MUCH ON THURSDAY WITH THE STRONG COLD
AIR ADVECTION IN PLACE...AS 850 HPA TEMPS FALL TO -20 TO -25
DEGREES C. HIGHS WILL ONLY REACH THE SINGLE DIGITS TO MID TEENS.
SOME ADDITIONAL UPSLOPE SNOW MAY OCCUR WITH IN THE NW FLOW FOR
THE HIGH TERRAIN AREAS OF WESTERN NEW ENGLAND...AND SOME LAKE
ENHANCED SNOW SHOWERS COULD ALSO BE OCCURRING INTO THE MOHAWK
VALLEY/SCHOHARIE COUNTY THANKS TO THE FLOW MOVING ACROSS LAKE
ONTARIO. SOME ADDITIONAL ACCUMULATION OF AN INCH OR TWO IS
POSSIBLE FOR THESE AREAS.
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 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 /01Z THURSDAY THROUGH MONDAY/...
SNOW WAS DEVELOPING ACROSS THE REGION AHEAD OF AN APPROACHING LOW
PRESSURE SYSTEM...WITH A LINE OF SNOW SQUALLS OCCURRING ACROSS
CENTRAL NEW YORK AND PENNSYLVANIA JUST AHEAD OF THE COLD FRONT.
THE HRRR INDICATES THE SNOW SQUALLS WILL WEAKEN AS THE MOVE
EASTWARD INTO EAST CENTRAL NEW YORK. DO EXPECT SNOW/SNOW SHOWERS
TO DEVELOP ACROSS THE FORECAST AREA TONIGHT WITH CLOUDS LOWERING.
VFR CONDITIONS WILL LOWER TO MVFR WITH THE SNOW. AN IMPROVEMENT
BACK TO VFR IS EXPECTED BY MID MORNING THURSDAY. CLOUDS ARE
EXPECTED TO DOMINATE THROUGH THE DAY.
WIND WILL BE LIGHT/VARIABLE TO SOUTHERLY OVERNIGHT. THEY WILL
SHIFT TO THE WEST AND INCREASING IN SPEED WITH THE PASSAGE OF THE
SYSTEM. AS THE SYSTEM DEEPENS THURSDAY 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...IAA/FRUGIS/HWJIV
SHORT TERM...HWJIV
LONG TERM...IRL
AVIATION...IAA
HYDROLOGY...FRUGIS/HWJIV
AREA FORECAST DISCUSSION
NWS ALBANY NY
359 AM EST TUE FEB 17 2015
.SYNOPSIS...
A STORM MOVING OFF THE MID ATLANTIC COAST MAY BRING SOME
LIGHT SNOW TO FAR SOUTHERN AREAS...OTHERWISE IT WILL BE MOSTLY
CLOUDY AND CONTINUED COLD TODAY. AN ARCTIC COLD FRONT WILL BRING
SOME SNOW SHOWERS TO THE REGION TOMORROW INTO TOMORROW NIGHT WITH
MORE BITTER COLD AIR TO FOLLOW FOR THURSDAY AND FRIDAY. TEMPERATURES
WILL REMAIN BELOW NORMAL THROUGH THE UPCOMING WEEKEND.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
AS OF 359 AM EST...IR SATELLITE IMAGERY SHOWS OUR REGION IS ON
THE NORTHERN EDGE OF A SHIELD OF CLOUDS FROM A STORM SYSTEM OVER
THE MID ATLANTIC STATES. THE FAR NORTHERN AND WESTERN AREAS OF THE
CWA ARE IN NEARLY CLEAR SKIES...WHICH IS ALLOWING FOR TEMPS TO
CONTINUE TO FREE FALL. PARTS OF THE ADIRONDACKS...INCLUDING THE
LAKE GEORGE AND GLENS FALLS AREAS...ARE -10 TO -30 DEGREES. WINDS
ARE NEARLY CALM...SO DESPITE THE FRIGID AIRMASS...THERE IS NO
ADDITIONAL WIND CHILL FACTOR IN PLACE. MEANWHILE...IN AREAS WHERE
CLOUD COVER IS PRESENT...TEMPS ARE MUCH WARMER...MAINLY ZERO TO 12
DEGREES. TEMPS IN THESE ARE ALREADY NEAR THEIR MINS...AND ARE
LIKELY TO HOLD STEADY OR ONLY SLOWLY FALL TOWARDS DAYBREAK.
WITH THE STORM SYSTEM MOVING OFF THE MID ATLANTIC COAST...SOME
LIGHT SNOW IS BEING REPORTED ACROSS THE POCONOS...NORTH
JERSEY...AND IN THE NYC METRO AREA. KENX RADAR SHOWS SOME LIGHT
RETURNS FURTHER NORTH THAN THAT...SUCH AS OVER THE CATSKILLS AND
MID HUDSON VALLEY...BUT THE VERY DRY AIRMASS IN PLACE AT LOW
LEVELS IS ALLOWING THIS PRECIP TO DRY UP BEFORE IT REACHES THE
SFC. THE 07Z 3KM HRRR SHOWS SOME LIGHT SNOWFALL MAY TRY TO FALL
ACROSS ULSTER...DUTCHESS...AND LITCHFIELD COUNTIES THROUGH ABOUT 9
AM. IF THE ATMOSPHERE IS ABLE TO MOISTEN UP ENOUGH...A DUSTING TO
AN INCH OF SNOW COULD BE POSSIBLE ACROSS THOSE AREAS. FURTHER
NORTH...NO SNOWFALL IS EXPECTED TO OCCUR. AFTER ABOUT MID
MORNING...POPS TAPER OFF ACROSS OUR AREA.
THE STORM SYSTEM WILL MOVE OUT TO SEA LATER TODAY. CLOUDY SKIES
WILL GRADUALLY GIVE WAY TO A FEW BREAKS FOR VALLEY AREAS BY LATE
IN THE DAY...OTHERWISE SKIES WILL REMAIN MOSTLY CLOUDY OVER THE
AREA. MAX TEMPS TODAY WILL GENERALLY BE IN THE TEENS...WITH SOME
READINGS NEAR 20 IN FAR SOUTHERN AREAS.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH THURSDAY/...
DRY WEATHER IS EXPECTED TO BE IN PLACE TONIGHT...WITH WEAK HIGH
PRESSURE IN PLACE OVER THE AREA. THERE MAY BE SOME BREAKS IN THE
CLOUDS...AND WITH LIGHT WINDS AND SNOWPACK IN PLACE...ANOTHER VERY
COLD NIGHT IS EXPECTED. TEMPS WILL RANGE BETWEEN 10 BELOW AND 10
ABOVE...WITH THE COLDEST READINGS OVER THE ADIRONDACKS...SRN
VT...AND BERKSHIRES.
AN ARCTIC COLD FRONT WILL BE APPROACHING THE REGION FROM THE GREAT
LAKES FOR WEDNESDAY. IN ADDITION TO A STRONG SHORTWAVE...THIS
FRONT WILL BE AIDED BY A TIGHT THERMAL GRADIENT ALOFT. BOTH THE
NAM12 AND THE 4KM WFO BTV WRF SUGGEST THAT A LINE OF CONVECTIVE
SNOW SQUALLS COULD ACCOMPANY THIS FRONTAL BOUNDARY AS IT CROSSES
OUR AREA WED AFTN INTO WED EVENING. WHILE SNOW AMOUNTS ARE LIKELY
BE LIGHT /MAINLY AN INCH OR LESS/...ANY SNOW SQUALL COULD BE
ACCOMPANIED BY A BRIEF REDUCTION IN VISIBILITY AND STRONG WINDS.
TEMPS WILL BE MILDER AHEAD OF THIS FRONT...WITH LOW TO MID 20S FOR
MANY AREAS.
BEHIND THE ARCTIC FRONT...MUCH COLDER AIR WILL MOVE INTO THE
REGION ONCE AGAIN FOR WED NIGHT INTO THURSDAY. TEMPS WILL FALL
TO 10 BELOW TO 10 ABOVE FOR WED NIGHT...AND WON/T RISE MUCH FOR
DURING THE DAY THURSDAY...WITH HIGHS ONLY ZERO TO 15 ABOVE OVER
THE AREA. IN ADDITION...THERE WILL BE A GUSTY W-NW BREEZE...ESP
FOR THE HIGH TERRAIN AREAS. SOME ADDITIONAL SNOW SHOWERS WILL BE
POSSIBLE WED NIGHT INTO THURSDAY AS THE UPPER LEVEL DISTURBANCE
MOVES ACROSS THE REGION...AND ANOTHER SFC LOW STARTS TO DEVELOP
OFF THE NEW ENGLAND COAST. AN ADDITIONAL COATING TO AN INCH WILL
BE POSSIBLE ACROSS THE REGION. ALSO...THERE MAY BE SOME LAKE
EFFECT ACTIVITY OFF LAKE ONTARIO AS WELL...AND THIS BAND COULD
EXTEND INTO PARTS OF THE WESTERN MOHAWK VALLEY AS WELL...DEPENDING
ON IT/S EXACT ORIENTATION AND INLAND EXTENT OFF THE LAKE. WE WILL
BE MONITORING THIS POTENTIAL CLOSELY OVER THE NEXT FEW DAYS.
&&
.LONG TERM /THURSDAY NIGHT THROUGH MONDAY/...
..BELOW TO MUCH BELOW NORMAL TEMPS CONTINUE THROUGH THE LONG TERM
PORTION OF THE FORECAST..
SO FAR FOR THE MONTH OF FEBRUARY WE ARE IN SECOND PLACE WITH RESPECT
TO THE AVERAGE COLDEST AND WELL WITHIN THE TOP 10 OF THE SNOWIEST
SINCE OUR RECORDS BEGAN BACK INTO THE 1800S. AS MORE COLD AIR AND
SNOW ARE IN THE FORECAST...WILL BE INTERESTING TO WATCH TRENDS WHEN
WE CLOSE OUT THE MONTH ON THE 28TH.
AS THE PREVIOUS EXCELLENT DISCUSSION DETAILED...DEPARTING UPPER
LOW/VORTEX WILL ALLOW FOR CLOUDS AND THE CHANCE FOR ADDITIONAL LIGHT
SNOW/SNOW SHOWERS THURSDAY NIGHT /MAINLY INTO THE TERRAIN/. AS
AROUND 500DM HEIGHTS AND H850 TEMPS WELL INTO THE SUB 20S CELSIUS
COMBINING WITH A RATHER TIGHT PRESSURE GRADIENT...ADDITIONAL WIND
CHILL HEADLINES APPEAR LIKELY AT THIS TIME. WE WILL CONTINUE TO
HIGHLIGHT THIS HAZARD IN THE HWO.
CONSENSUS CONTINUES TO FAVOR RIDGING TO EVOLVE ACROSS THE ENTIRE
REGION FRIDAY INTO FRIDAY EVENING. WHILE WE WILL BE NULL OF
PRECIPITATION...IT WILL REMAIN COLD WITH TEMPERATURES MAINLY INTO
THE SINGLE DIGITS. WINDS WILL BE DIMINISHING AS WE SHOULD
EXPERIENCE A BREAK FROM THE WIND CHILL HEADLINES.
HOWEVER...HUDSON BAY VORTEX BECOMES REESTABLISHED THIS WEEKEND. A
FEW PV ANOMALIES ARE SET TO DIVE SOUTHEAST FROM THE NORTHWEST
TERRITORIES AND MOVE ACROSS THE REGION THROUGH THE WEEKEND. THE
ECMWF HAS RELAXED ITS HIGHLY AMPLIFIED SURFACE WAVE DEVELOPMENT AND
IS MORE IN LINE WITH THE GFS AS A PROGRESSIVE WAVE. THIS WILL ONLY
ADD TO THE SNOW BASE WITH AVERAGE GFS/ECMWF QPF VALUES BETWEEN ONE
QUARTER AND ONE HALF INCH. WHERE THESE MODELS DIFFER IS THE EXIT
STRATEGY WHERE THE ECMWF IS MUCH QUICKER THAN THE GFS. FOR NOW...WE
WILL INCREASE POPS FOR THIS WEEKEND WITH MORE ACCUMULATING LIGHT
SNOW.
SUNDAY NIGHT INTO MONDAY...ANOTHER POTENTIALLY BITTERLY COLD NIGHT
WITH THE COMBINATION OF LIKELY MORE FRESH SNOW...DIMINISHING WINDS
AS THE SURFACE HIGH BUILDS INTO THE REGION AND CLEARING SKIES.
&&
.AVIATION /09Z TUESDAY THROUGH SATURDAY/...
THICKENING AND LOWERING CLOUDS TO BE EXPECTED THE REMAINDER OF
THE OVERNIGHT PERIOD AS CIGS SHOULD REMAIN IN VFR TERRITORY.
RESTRICTIONS ARRIVE MAINLY AT KPOU TOWARD MORNING WITH SOME LIGHT
SNOW AND LOWERING CIGS. KPSF REMAINS ON THE NORTHERN PERIPHERY OF
THIS SYSTEM AS WE WILL CONTINUE WITH VCSH AT THIS TIME. AS THE
STORM PASSES OFF THE MID ATLANTIC COAST...LOWER LEVEL MOISTURE
BORDERING VFR/MVFR WILL REMAIN IN THE FORECAST FOR THE BALANCE OF
THE DAY.
WINDS AT KPSF WILL REMAIN FROM THE WEST WITH DIMINISHING SPEEDS AS
WINDS ELSEWHERE WILL BE OR BECOME LIGHT AND VARIABLE OVERNIGHT
THROUGH TUESDAY.
OUTLOOK...
TUE NIGHT-WED AM: NO OPERATIONAL IMPACT. NO SIG WX.
WED PM-WED NIGHT: LOW OPERATIONAL IMPACT. CHC -SHSN.
THU-FRI: NO OPERATIONAL IMPACT. NO SIG WX.
SAT: MODERATE OPERATIONAL IMPACT. CHC SN.
&&
.HYDROLOGY...
ICE WILL CONTINUE TO THICKEN ON AREA RIVERS...STREAMS...LAKES...AND
PONDS...AS CONTINUED BELOW NORMAL TEMPERATURES REMAIN IN PLACE
THROUGH THE ENTIRE UPCOMING WEEK. TEMPERATURES ARE NOT EXPECTED TO
RISE ABOVE FREEZING DURING THE NEXT FIVE DAYS.
ANY PRECIP...ALL IN THE FORM OF SNOW...WILL BE FAIRLY LIGHT OVER
THE NEXT FEW DAYS. SOME LIGHT SNOW MAY IMPACT FAR SOUTHERN AREAS
THROUGH MID MORNING TODAY...BUT AMOUNTS WILL BE SMALL AND WILL
HAVE NO IMMEDIATE HYDROLOGIC IMPACT. SOME SNOW SHOWERS MAY IMPACT
THE ENTIRE REGION AS WELL FOR WEDNESDAY AFTERNOON THROUGH THURSDAY
AS WELL.
SOME GAGES WILL EXPERIENCE ICE EFFECTS...AND SOME ERRONEOUS DATA
MAY BE SEEN FROM TIME TO TIME.
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...FRUGIS
NEAR TERM...FRUGIS
SHORT TERM...FRUGIS
LONG TERM...BGM
AVIATION...BGM
HYDROLOGY...FRUGIS
AREA FORECAST DISCUSSION
NWS CHARLESTON SC
937 AM EST TUE FEB 17 2015
.SYNOPSIS...
A COLD FRONT WILL MOVE OFFSHORE THIS MORNING AS A STRENGTHENING LOW
PRESSURE SYSTEM SHIFTS OFF THE MID-ATLANTIC COAST. A SERIES OF
REINFORCING COLD FRONTS WILL THEN MOVE THROUGH TONIGHT AND AGAIN
LATE WEDNESDAY. ARCTIC HIGH PRESSURE WILL THEN BUILD INTO THE REGION
AND PERSIST THROUGH FRIDAY. A COASTAL TROUGH WILL DEVELOP ON
SATURDAY...THEN LIFT NORTH ON SUNDAY AHEAD OF AN APPROACHING COLD
FRONT. THE COLD FRONT WILL MOVE THROUGH SUNDAY NIGHT THEN STALL
OFFSHORE AS A WAVE OF LOW PRESSURE TRACKS ALONG IT EARLY NEXT
WEEK.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
THE COLD FRONT IS ALONG OR JUST OFF THE COAST AT 17/14Z...EXCEPT
ALONG THE UPPER CHARLESTON COUNTY COAST. THE FRONT WILL CLEAR
MCCLELLANVILLE WITHIN THE HOUR.
MOST OF THE SIGNIFICANT RAINS HAVE ENDED. THE ONLY EXCEPTION IS
ALONG THE UPPER GEORGIA COAST WHERE A SECONDARY SURGE OF MOISTURE
IS WORKING ITS WAY IN FROM THE SOUTHWEST. ADJUSTED POPS TO ACCOUNT
OR CURRENT TRENDS. RAINS WILL GRADUALLY END LATER THIS AFTERNOON
ALONG THE GEORGIA COAST...BUT WILL INCREASE AGAIN AS YET ANOTHER
MOISTURE SURGE WORKS ACROSS THE AREA.
MOST AREAS HAVE LIKELY SEEN THEIR DAYTIME HIGH AS TEMPERATURES
ARE FALLING QUICKLY BEHIND THE COLD FRONT. THE DEGREE OF THERMAL
RECOVERY THIS AFTERNOON REMAINS HIGHLY UNCERTAIN WITH SOME
GUIDANCE INDICATING INLAND AREAS COULD REMAIN IN THE 30S WHILE
HOLDING IN THE 40S AT THE COAST. USED A 30/30/30 BLEND OF ENSEMBLE
DATA...H3R AND RAP DATA TO CONSTRUCT HOURLY TEMPERATURES THROUGH
SUNSET. ALSO RECALCULATED HIGH TEMPERATURES BASED ON THIS...BUT
AGAIN...DAILY HIGHS HAVE LIKELY ALREADY OCCURRED IN MOST AREAS.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH FRIDAY/...
TONIGHT...THE UPPER TROUGH AXIS WILL BE APPROACHING LATE SO THERE
WILL BE SOME PVA AND JET FORCING WHICH WILL MAINTAIN AT LEAST A
SLIGHT CHANCE FOR SHOWERS NEAR THE COAST THROUGH THE EVENING.
TEMPERATURES WILL PLUMMET TOWARD NEAR THE FREEZING MARK LATE BUT
SUFFICIENT MOISTURE SHOULD BE OFFSHORE BY THEN.
WEDNESDAY AND WEDNESDAY NIGHT...A LONG WAVE TROUGH WILL PREVAIL
OVER THE EASTERN UNITED STATES IN THE MID AND UPPER LEVELS OF THE
ATMOSPHERE. AT THE SURFACE...HIGH PRESSURE WILL BUILD INTO THE
REGION FROM THE SOUTHERN PLAINS TO START THE DAY BUT THEN A
REINFORCING COLD FRONT WILL MOVE THROUGH LATE...WITH ARCTIC HIGH
PRESSURE TO FOLLOW THROUGH WEDNESDAY NIGHT.
A DRY WESTERLY FLOW WILL ENSURE THAT NO PRECIPITATION ACCOMPANIES
THE FRONTAL PASSAGE...HOWEVER THERE COULD BE A FEW CLOUDS AROUND
RESULTING IN PARTLY CLOUDY SKIES. A DOWNSLOPE COMPONENT TO THE FLOW
SHOULD ALLOW TEMPERATURES TO WARM TO AROUND 50 OR THE LOWER 50S FOR
HIGHS ACROSS THE AREA. BREEZY CONDITIONS ARE EXPECTED TO DEVELOP IN
THE AFTERNOON AS A LOW LEVEL JET STRENGTHENS AHEAD OF THE COLD
FRONT...WITH GUSTS OF 25-35 MPH...HIGHEST NEAR AND JUST SOUTH OF THE
SAVANNAH RIVER. STRONG COLD AIR ADVECTION IN WAKE OF THE FRONT WILL
PREVENT WINDS FROM DECOUPLING WEDNESDAY NIGHT...AND BREEZY
CONDITIONS ARE EXPECTED TO CONTINUE. IT LOOKS TO BE A COLD NIGHT
WEDNESDAY NIGHT...WITH LOWS IN THE MID 20S ACROSS MUCH OF THE AREA.
THE COMBINATION OF COLD TEMPERATURES AND WIND SHOULD LOWER WIND
CHILL VALUES WELL INTO THE TEENS...THUS WIND CHILL ADVISORIES MAY BE
NEEDED.
THURSDAY AND THURSDAY NIGHT...THE LONG WAVE TROUGH WILL GRADUALLY
SHIFT EASTWARD...WITH THE 500 MB FLOW ALONG THE WESTERN PERIPHERY OF
THE TROUGH FUNNELING IN WHAT WILL LIKELY BE THE COLDEST AIRMASS OF
THE SEASON DIRECT FROM THE ARCTIC. IN FACT...850 MB TEMPERATURES
LOOK TO BE AS COLD AS -10C TO -17C. MEANWHILE...EXPANSIVE HIGH
PRESSURE AT THE SURFACE WILL BUILD IN FROM THE MISSISSIPPI VALLEY.
DESPITE NEARLY FULL SUNSHINE...THICKNESS VALUES ONLY SUPPORT HIGHS
IN THE LOWER TO MID 30S ACROSS MUCH OF THE AREA. HOWEVER...FIGURE A
DOWNSLOPE FLOW MAY OFFSET THAT A BIT SO THE FORECAST WILL INDICATE
HIGHS IN THE MID AND UPPER 30S...EXCEPT AROUND 40 OR IN THE LOWER
40S ALONG AND SOUTH OF I-16. THIS WILL VERY LIKELY RESULT IN RECORD
LOW MAXIMUMS FOR OUR PRIMARY CLIMATE SITES. CONTINUED COLD AIR
ADVECTION THURSDAY NIGHT MAY PREVENT WINDS FROM FULLY
DECOUPLING...WITH LOWS IN THE UPPER TEENS TO LOWER 20S ACROSS THE
AREA. WIND CHILL ADVISORIES LOOK MOST LIKELY LATE THURSDAY NIGHT AS
A RESULT...WITH WIND CHILLS POSSIBLY FALLING AS LOW AS 5F TO 15F
ABOVE ZERO.
FRIDAY...AS THE LONG WAVE TROUGH LIFTS/WEAKENS...HEIGHTS WILL
GRADUALLY RISE ACROSS THE AREA. AT THE SURFACE...HIGH PRESSURE WILL
SHIFT ACROSS THE CENTRAL APPALACHIANS THEN OVER THE SOUTHERN MID-
ATLANTIC AND CAROLINAS. STILL A VERY COLD AIR MASS...WITH HIGHS IN
THE UPPER 30S TO LOWER 40S ACROSS MOST OF THE AREA.
LAKE WINDS...WINDS ON LAKE MOULTRIE COULD REACH LAKE WIND
ADVISORY CRITERIA SOMETIME DURING THE LATE WEDNESDAY THROUGH
THURSDAY NIGHT TIME PERIOD AS STRONG COLD AIR ADVECTION DEVELOPS
OVER THE AREA.
&&
.LONG TERM /FRIDAY NIGHT THROUGH MONDAY/...
A MORE PROGRESSIVE ZONAL UPPER LEVEL FLOW WILL PREVAIL INTO THE
START OF THE WEEKEND. AS A RESULT...SURFACE HIGH PRESSURE WILL SHIFT
OFF THE MID-ATLANTIC COAST WITH A WEAK COASTAL TROUGH SETTING UP
ALONG THE SOUTHEAST COAST. SOME ENHANCED LOW LEVEL CONVERGENCE COULD
RESULT IN ISOLATED SHOWERS ALONG THE COAST AND INTO THE CHARLESTON
TRI-COUNTY AREA. THE COASTAL TROUGH WILL LIFT NORTHWARD ON
SUNDAY...AS A COLD FRONT APPROACHES FROM THE NORTHWEST. TEMPERATURES
WILL BE ON A WARMING TREND THROUGH THE WEEKEND...ACTUALLY RETURNING
TO ABOVE NORMAL BRIEFLY ON SUNDAY.
THE COLD FRONT SHOULD MOVE THROUGH SUNDAY NIGHT...ACCOMPANIED BY
SHOWERS. THE FRONT THEN APPEARS TO STALL OFF THE SOUTHEAST COAST
INTO EARLY NEXT WEEK...AND EXHIBIT ANAFRONTAL CHARACTERISTICS WITH
PRECIPITATION OCCURRING TO ITS NORTH AND WEST OVER THE AREA. THERE IS
CONCERN THAT COLD AIR FILTERING INTO THE REGION BEHIND THE FRONT
COULD RESULT IN SOME TYPE OF WINTRY PRECIPITATION AND WE WILL NEED
TO MONITOR THIS OVER THE COURSE OF THE WEEK.
&&
.AVIATION /15Z TUESDAY THROUGH SATURDAY/...
THE STEADY RAIN WILL PUSH OFFSHORE SHORTLY AFTER THE TAF/S
INITIALIZE...BUT SOME LINGERING SHOWERS ARE POSSIBLE THROUGH
MIDDAY SO VICINITY SHOWERS WILL BE MENTIONED IN THE FORECAST.
BEHIND A COLD FRONT PUSHING OFFSHORE BY MID-MORNING...A PERIOD OF
IFR CEILINGS AT KCHS AND LOW-END MVFR CEILINGS AT KSAV ARE
EXPECTED THROUGH ABOUT 18Z. CEILINGS SHOULD THEN REMAIN MVFR AT
BOTH TERMINALS THROUGH LATE AFTERNOON...BEFORE RISING TO VFR FOR
THE REMAINDER OF THE FORECAST PERIOD. GUSTY WINDS ARE POSSIBLE
THROUGH MIDDAY AS WELL.
EXTENDED AVIATION OUTLOOK...GUSTY WINDS WILL OCCUR AT THE TERMINALS
THROUGH THURSDAY. MVFR OR LOWER CEILINGS ARE POSSIBLE FRIDAY NIGHT
INTO SATURDAY AS A COASTAL TROUGH DEVELOPS. OTHERWISE...VFR
CONDITIONS ARE EXPECTED TO PREVAIL.
&&
.MARINE...
TODAY...EXPECT IMPROVING CONDITIONS ALL WATERS TODAY. DROPPED THE
GALE WARNING FOR CHARLESTON COUNTY WATERS BASED ON THE LATEST
PILOT BOAT REPORTS. GALE WARNINGS REMAIN IN EFFECT FOR THE
GEORGIA OFFSHORE WATERS THROUGH EARLY AFTERNOON.
WEDNESDAY THROUGH SUNDAY...CONDITIONS WILL DETERIORATE OVER THE
WATERS LATE WEDNESDAY AS STRONG COLD AIR ADVECTION DEVELOPS IN WAKE
OF A PASSING COLD FRONT...AND GUSTY WINDS WILL CONTINUE THROUGH
THURSDAY NIGHT. SMALL CRAFT ADVISORIES WILL LIKELY BE NEEDED FOR ALL
WATERS DURING THIS PERIOD...WITH A WINDOW OF GALE FORCE GUSTS
POSSIBLE OVER THE OUTER GEORGIA WATERS MAINLY WEDNESDAY NIGHT. THE
SURFACE PRESSURE GRADIENT WILL RELAX LATE IN THE WEEK INTO THE
WEEKEND AS HIGH PRESSURE PASSES TO THE NORTH AND A COASTAL TROUGH
EVENTUALLY DEVELOPS. A COLD FRONT WILL THEN APPROACH FROM THE
NORTHWEST LATE IN THE WEEKEND...BUT CONDITIONS SHOULD REMAIN BELOW
SMALL CRAFT ADVISORY LEVELS.
&&
.FIRE WEATHER...
RAINFALL EARLY THIS MORNING WILL HELP TO MOISTEN FUELS...BUT AMOUNTS
WILL GENERALLY BE AROUND 1/2 INCH OR LESS. BREEZY CONDITIONS AND A
DRY DOWNSLOPE FLOW WILL ALLOW FUELS TO BEGIN TO DRY OUT WEDNESDAY
AND THERE COULD ONCE AGAIN BE SOME FIRE WEATHER CONCERNS BY THURSDAY
WHEN HUMIDITY FALLS TO 15-25 PERCENT AND WINDS GUST 25-35 MPH.
&&
.TIDES/COASTAL FLOODING...
TIDES COULD APPROACH ADVISORY LEVELS DURING THE EARLY MORNING HIGH
TIDE CYCLE WED...ESPECIALLY ALONG THE SC COAST.
&&
.CLIMATE...
RECORD LOWS FOR FEBRUARY 19...
NORTH CHARLESTON /KCHS/...20 SET IN 1968
DOWNTOWN CHARLESTON /KCXM/...21 SET IN 1979
SAVANNAH /KSAV/...19 SET IN 1958
RECORD LOW MAX TEMPS FOR FEBRUARY 19...
NORTH CHARLESTON /KCHS/...42 SET IN 1972
DOWNTOWN CHARLESTON /KCXM/...42 LAST SET IN 1979
SAVANNAH /KSAV/...40 SET IN 1910
RECORD LOWS FOR FEBRUARY 20...
NORTH CHARLESTON /KCHS/...22 LAST SET IN 1968
DOWNTOWN CHARLESTON /KCXM/...28 SET IN 1958
SAVANNAH /KSAV/...22 SET IN 1958
RECORD LOW MAX TEMPS FOR FEBRUARY 20...
NORTH CHARLESTON /KCHS/...44 SET IN 1959
DOWNTOWN CHARLESTON /KCXM/...44 SET IN 1978
SAVANNAH /KSAV/...44 SET IN 1908
&&
.CHS WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
SC...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 2 PM EST THIS AFTERNOON FOR AMZ350-
352-354.
GALE WARNING UNTIL 2 PM EST THIS AFTERNOON FOR AMZ374.
&&
$$
ST
AREA FORECAST DISCUSSION
NWS COLUMBIA SC
645 AM EST TUE FEB 17 2015
.SYNOPSIS...
LOW PRESSURE WILL MOVE OFF THE COAST TODAY. PRECIPITATION WILL END
EARLY THIS MORNING. WELL BELOW NORMAL TEMPERATURES EXPECTED
THROUGH THE WEEK UNDER THE INFLUENCE OF AN ARCTIC AIR MASS.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
LATEST HRRR AND RAP GUIDANCE INDICATES PRECIPITATION LIKELY PUSH
EAST OF THE REGION EARLY THIS MORNING AS ISENTROPIC DOWN-GLIDE
DEVELOPS. WARNINGS AND ADVISORIES EXPIRE AT 700 AM. MODELS
INDICATE COLD ADVECTION DURING THE DAY AND CONSIDERABLE CLOUDINESS
UPSTREAM SO EXPECT TEMPERATURES TO STRUGGLE TO RISE THROUGH THE
40S.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM WEDNESDAY/...
EASTERN CONUS UPPER LEVEL TROUGH AMPLIFIES TONIGHT AND WEDNESDAY
WITH RESULTING STRENGTHENING COLD ADVECTION. LIGHT WINDS TONIGHT
SO TEMPERATURES WILL FALL BELOW FREEZING. INCREASING WEST LOW
LEVEL WINDS EXPECTED DURING THE DAY WEDNESDAY...LAKE WIND ADVISORY
WILL LIKELY BE NEEDED WITH SUSTAINED WINDS AROUND 20 KTS AND
FREQUENT GUSTS ABOVE 30 KTS POSSIBLE. STRONG SHORT WAVES ROTATING
THROUGH REGION DURING THE DAY...DEEP MOISTURE LIMITED BUT CANT
RULE OUT SOME LIGHT SNOW SHOWERS IN THE AFTERNOON MAINLY NORTH
MIDLANDS. MODEL SOUNDINGS NORTH MIDLANDS SUPPORTS A LOW POPS IN
THAT REGION. CONSIDERABLE CLOUDS LIKELY THROUGH THE DAY THEN
CLEARING BEHIND THE SHORT WAVE IN THE EVENING. WINDS LIKELY TO
STAY UP THROUGH AT LEAST MIDNIGHT WITH STRONG MIXING/CONTINUED
COLD ADVECTION. MAX TEMPERATURE FORECAST BELOW GUIDANCE.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH MONDAY/...
GENERALLY DRY INTO THE WEEKEND. HIGH PRESSURE WILL BUILD IN FROM THE
WEST WITH A REINFORCING SHOT OF ARCTIC AIR MOVING INTO THE AREA
THURSDAY AND FRIDAY. ANOTHER LOW PRESSURE SYSTEM DEVELOPING IN
THE SOUTHERN PLAINS BY EARLY SATURDAY WILL MOVE INTO THE TN VALLEY
BY SUNDAY AS MORE HIGH PRESSURE BUILDS IN FROM THE NORTH. AS A
RESULT...A COLD AIR DAMMING SCENARIO MAY OVER THE WEEKEND INTO
MONDAY. STILL LOTS OF QUESTIONS REGARDING TIMING AND PLACEMENT OF
THIS NEXT SYSTEM AND THE POSSIBILITY OF ANY WINTRY PRECIPITATION
EARLY NEXT WEEK. BUT WITH SOME MANY MODEL UNCERTAINTIES AT THIS
TIME...FOR NOW WILL KEEP PRECIPITATION ALL LIQUID SATURDAY INTO
MONDAY WITH CHANCE POPS. TEMPERATURES GENERALLY BELOW NORMAL THROUGH
THE EXTENDED PERIOD...WITH WELL BELOW NORMAL TEMPERATURES THURSDAY
AND FRIDAY. IN FACT...CURRENT MEX/MEN GUIDANCE HAS TEMPERATURES
ABOUT 20 TO 25 DEGREES BELOW NORMAL FOR CAE AND AGS THURSDAY AND
FRIDAY.
&&
.AVIATION /12Z TUESDAY THROUGH SATURDAY/...
IFR CIGS MVFR/VFR VSBYS ACROSS MOST OF THE AREA AS LOW PRESSURE
WORKS NORTHEAST ALONG THE COAST. EXPECT MVFR CIGS VFR VSBYS AFTER
16Z WITH VFR CIGS/VSBYS AFTER 19Z.
EXTENDED AVIATION OUTLOOK...BREEZY CONDITIONS EXPECTED WEDNESDAY
AND THURSDAY. CIG RESTRICTIONS AND SHOWER CHANCES COULD RETURN
SAT/SUN.
&&
.CAE WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
GA...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS COLUMBIA SC
604 AM EST TUE FEB 17 2015
.SYNOPSIS...
LOW PRESSURE WILL MOVE OFF THE COAST TODAY. PRECIPITATION WILL END
EARLY THIS MORNING. WELL BELOW NORMAL TEMPERATURES EXPECTED
THROUGH THE WEEK UNDER THE INFLUENCE OF AN ARCTIC AIR MASS.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
LATEST HRRR AND RAP GUIDANCE INDICATES PRECIPITATION LIKELY PUSH
EAST OF THE REGION EARLY THIS MORNING AS ISENTROPIC DOWN-GLIDE
DEVELOPS. PLAN IS TO LET WARNINGS AND ADVISORIES EXPIRE AT 700 AM. MODELS
INDICATE COLD ADVECTION DURING THE DAY AND CONSIDERABLE CLOUDINESS
UPSTREAM SO EXPECT TEMPERATURES TO STRUGGLE TO RISE THROUGH THE
40S.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM WEDNESDAY/...
EASTERN CONUS UPPER LEVEL TROUGH AMPLIFIES TONIGHT AND WEDNESDAY
WITH RESULTING STRENGTHENING COLD ADVECTION. LIGHT WINDS TONIGHT
SO TEMPERATURES WILL FALL BELOW FREEZING. INCREASING WEST LOW
LEVEL WINDS EXPECTED DURING THE DAY WEDNESDAY...LAKE WIND ADVISORY
WILL LIKELY BE NEEDED WITH SUSTAINED WINDS AROUND 20 KTS AND
FREQUENT GUSTS ABOVE 30 KTS POSSIBLE. STRONG SHORT WAVES ROTATING
THROUGH REGION DURING THE DAY...DEEP MOISTURE LIMITED BUT CANT
RULE OUT SOME LIGHT SNOW SHOWERS IN THE AFTERNOON MAINLY NORTH
MIDLANDS. MODEL SOUNDINGS NORTH MIDLANDS SUPPORTS A LOW POPS IN
THAT REGION. CONSIDERABLE CLOUDS LIKELY THROUGH THE DAY THEN
CLEARING BEHIND THE SHORT WAVE IN THE EVENING. WINDS LIKELY TO
STAY UP THROUGH AT LEAST MIDNIGHT WITH STRONG MIXING/CONTINUED
COLD ADVECTION. MAX TEMPERATURE FORECAST BELOW GUIDANCE.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH MONDAY/...
GENERALLY DRY INTO THE WEEKEND. HIGH PRESSURE WILL BUILD IN FROM THE
WEST WITH A REINFORCING SHOT OF ARCTIC AIR MOVING INTO THE AREA
THURSDAY AND FRIDAY. ANOTHER LOW PRESSURE SYSTEM DEVELOPING IN
THE SOUTHERN PLAINS BY EARLY SATURDAY WILL MOVE INTO THE TN VALLEY
BY SUNDAY AS MORE HIGH PRESSURE BUILDS IN FROM THE NORTH. AS A
RESULT...A COLD AIR DAMMING SCENARIO MAY OVER THE WEEKEND INTO
MONDAY. STILL LOTS OF QUESTIONS REGARDING TIMING AND PLACEMENT OF
THIS NEXT SYSTEM AND THE POSSIBILITY OF ANY WINTRY PRECIPITATION
EARLY NEXT WEEK. BUT WITH SOME MANY MODEL UNCERTAINTIES AT THIS
TIME...FOR NOW WILL KEEP PRECIPITATION ALL LIQUID SATURDAY INTO
MONDAY WITH CHANCE POPS. TEMPERATURES GENERALLY BELOW NORMAL THROUGH
THE EXTENDED PERIOD...WITH WELL BELOW NORMAL TEMPERATURES THURSDAY
AND FRIDAY. IN FACT...CURRENT MEX/MEN GUIDANCE HAS TEMPERATURES
ABOUT 20 TO 25 DEGREES BELOW NORMAL FOR CAE AND AGS THURSDAY AND
FRIDAY.
&&
.AVIATION /11Z TUESDAY THROUGH SATURDAY/...
IFR CIGS MVFR/VFR VSBYS ACROSS MOST OF THE AREA AS LOW PRESSURE
WORKS NORTHEAST ALONG THE COAST. EXPECT MVFR CIGS VFR VSBYS AFTER
16Z WITH VFR CIGS/VSBYS AFTER 19Z.
EXTENDED AVIATION OUTLOOK...BREEZY CONDITIONS EXPECTED WEDNESDAY
AND THURSDAY. CIG RESTRICTIONS AND SHOWER CHANCES COULD RETURN
SAT/SUN.
&&
.CAE WATCHES/WARNINGS/ADVISORIES...
SC...ICE STORM WARNING UNTIL 7 AM EST THIS MORNING FOR SCZ015-016-
020-021.
FREEZING RAIN ADVISORY UNTIL 7 AM EST THIS MORNING FOR SCZ022-
026>028.
GA...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS COLUMBIA SC
405 AM EST TUE FEB 17 2015
.SYNOPSIS...
LOW PRESSURE WILL MOVE OFF THE COAST TODAY. PRECIPITATION WILL END
EARLY THIS MORNING. WELL BELOW NORMAL TEMPERATURES EXPECTED
THROUGH THE WEEK UNDER THE INFLUENCE OF AN ARCTIC AIR MASS.
&&
.NEAR TERM /THROUGH TODAY/...
LATEST HRRR AND RAP GUIDANCE INDICATES PRECIPITATION LIKELY PUSH
EAST OF THE REGION EARLY THIS MORNING AS ISENTROPIC DOWN-GLIDE
DEVELOPS. PLAN IS TO LET WARNINGS AND ADVISORIES EXPIRE AT 700 AM. MODELS
INDICATE COLD ADVECTION DURING THE DAY AND CONSIDERABLE CLOUDINESS
UPSTREAM SO EXPECT TEMPERATURES TO STRUGGLE TO RISE THROUGH THE
40S.
&&
.SHORT TERM /TONIGHT THROUGH 6 PM WEDNESDAY/...
EASTERN CONUS UPPER LEVEL TROUGH AMPLIFIES TONIGHT AND WEDNESDAY
WITH RESULTING STRENGTHENING COLD ADVECTION. LIGHT WINDS TONIGHT
SO TEMPERATURES WILL FALL BELOW FREEZING. INCREASING WEST LOW
LEVEL WINDS EXPECTED DURING THE DAY WEDNESDAY...LAKE WIND ADVISORY
WILL LIKELY BE NEEDED WITH SUSTAINED WINDS AROUND 20 KTS AND
FREQUENT GUSTS ABOVE 30 KTS POSSIBLE. STRONG SHORT WAVES ROTATING
THROUGH REGION DURING THE DAY...DEEP MOISTURE LIMITED BUT CANT
RULE OUT SOME LIGHT SNOW SHOWERS IN THE AFTERNOON MAINLY NORTH
MIDLANDS. MODEL SOUNDINGS NORTH MIDLANDS SUPPORTS A LOW POPS IN
THAT REGION. CONSIDERABLE CLOUDS LIKELY THROUGH THE DAY THEN
CLEARING BEHIND THE SHORT WAVE IN THE EVENING. WINDS LIKELY TO
STAY UP THROUGH AT LEAST MIDNIGHT WITH STRONG MIXING/CONTINUED
COLD ADVECTION. MAX TEMPERATURE FORECAST BELOW GUIDANCE.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH MONDAY/...
GENERALLY DRY INTO THE WEEKEND. HIGH PRESSURE WILL BUILD IN FROM THE
WEST WITH A REINFORCING SHOT OF ARCTIC AIR MOVING INTO THE AREA
THURSDAY AND FRIDAY. ANOTHER LOW PRESSURE SYSTEM DEVELOPING IN
THE SOUTHERN PLAINS BY EARLY SATURDAY WILL MOVE INTO THE TN VALLEY
BY SUNDAY AS MORE HIGH PRESSURE BUILDS IN FROM THE NORTH. AS A
RESULT...A COLD AIR DAMMING SCENARIO MAY OVER THE WEEKEND INTO
MONDAY. STILL LOTS OF QUESTIONS REGARDING TIMING AND PLACEMENT OF
THIS NEXT SYSTEM AND THE POSSIBILITY OF ANY WINTRY PRECIPITATION
EARLY NEXT WEEK. BUT WITH SOME MANY MODEL UNCERTAINTIES AT THIS
TIME...FOR NOW WILL KEEP PRECIPITATION ALL LIQUID SATURDAY INTO
MONDAY WITH CHANCE POPS. TEMPERATURES GENERALLY BELOW NORMAL THROUGH
THE EXTENDED PERIOD...WITH WELL BELOW NORMAL TEMPERATURES THURSDAY
AND FRIDAY. IN FACT...CURRENT MEX/MEN GUIDANCE HAS TEMPERATURES
ABOUT 20 TO 25 DEGREES BELOW NORMAL FOR CAE AND AGS THURSDAY AND
FRIDAY.
&&
.AVIATION /07Z TUESDAY THROUGH SATURDAY/...
IFR CIGS MVFR VSBYS ACROSS ALL BUT THE SE PORTIONS OF THE FORECAST
AREA WHICH REMAINS VFR. STRONG LOW LEVEL JET AHEAD OF THE LOW
WARRANTS INCLUSION OF LLWS. LOW PRESSURE OVER CENTRAL GA WILL
TRACK EAST ACROSS CENTRAL GA AND EASTERN SC TONIGHT...MAINLY ALONG
THE WARM FRONT THAT EXTENDS FROM JUST SOUTH OF AUGUSTA TO MYRTLE
BEACH. FREEZING RAIN MAINLY NORTH OF A SALUDA TO BISHOPVILLE LINE
AND RAIN SOUTH OF THE LINE. MODELS HAVE THE BACK EDGE OF THE
PRECIP FROM A CHARLOTTE TO AUGUSTA LINE AROUND 13Z SWEEPING
EASTWARD OUT OF THE AREA BY 17Z WITH SLOW IMPROVEMENT IN CIGS
EXPECTED DURING THE DAY.
EXTENDED AVIATION OUTLOOK...BREEZY CONDITIONS EXPECTED WEDNESDAY
AND THURSDAY. CIG RESTRICTIONS AND SHOWER CHANCES COULD RETURN
SAT/SUN.
&&
.CAE WATCHES/WARNINGS/ADVISORIES...
SC...ICE STORM WARNING UNTIL 7 AM EST THIS MORNING FOR SCZ015-016-
020-021.
FREEZING RAIN ADVISORY UNTIL 7 AM EST THIS MORNING FOR SCZ022-
026>028.
GA...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
337 PM CST TUE FEB 17 2015
.SHORT TERM...
320 PM CST
TONIGHT THROUGH THURSDAY...
MAIN CONCERN IS WITH BITTERLY COLD TEMPERATURES AND WIND CHILLS AS
NEAR RECORD COLD AIR MASS FOR MID TO LATE FEBRUARY IMPACTS THE AREA.
IN ADDITION...EXPECTING FAIRLY WIDESPREAD SNOW SHOWERS LATE TONIGHT
INTO WEDNESDAY MORNING.
MORNING RAOBS SHOWED HEART OF COLD AIR MASS...WITH 850 MB TEMPS OF
ABOUT -25 TO -30C FROM KINL UP TO HUDSON BAY. STRONG PV ANOMALY ON
LEADING EDGE OF THIS AIR MASS IS NOTED ON W/V IMAGERY FROM EASTERN
DAKOKTAS INTO WESTERN ONTARIO AND THIS WILL MOVE OVER THE AREA
TONIGHT INTO EARLY THURSDAY. IN NEAR TERM...WILL CONTINUE TO SEE
OCCASIONAL FLURRIES...WITH LINGERING SNOW SHOWERS EXITING NW
INDIANA. FORCING FROM UPPER WAVE/PV ANOMALY AND STEEPENING OF
LAPSE RATES SHOULD RESULT IN FAIRLY WIDESPREAD SCATTERED SNOW
SHOWERS PIVOTING SOUTHEASTWARD FROM AROUND MIDNIGHT TONIGHT
THROUGH EARLY THURSDAY MORNING. SIMILAR TO PREVIOUS OCCURRENCES
WITHIN THE PAST WEEK...NOT ALL AREAS WILL SEE ACCUMULATIONS...BUT
WOULDNT BE SURPRISED IF HEAVIER SNOW SQUALLS ARE EMBEDDED WITHIN
SCATTERED SNOW SHOWER ACTIVITY...YIELDING LOCALLY 1/2 INCH TO 1
INCH ACCUMS AND SIGNIFICANTLY REDUCED VISIBILITY. COLD ADVECTION
SHOULD FORCE TEMPERATURES DOWN TO ROUGHLY 0 TO +6 RANGE BY
DAYBREAK WEDNESDAY.
TEMPERATURE TRENDS ARE TRICKY ON WEDNESDAY BECAUSE OF HOW ANOMALOUS
AIR MASS IS. MINUS MID TO UPPER 20SC AIRMASS AT 850 MB PROGGED BY
LATE IN THE DAY IS AMONGST THE COLDEST OBSERVED AT ILX/DVN IN THE
MONTH OF FEBRUARY...AND ESPECIALLY THIS LATE IN THE MONTH. HAVE
SHOWN A VERY MINIMAL RECOVERY FROM MORNING LOWS INTO MID DAY/HIGHS
MID TO HIGH POSITIVE SINGLE DIGITS/FOLLOWED BY A FALL IN THE
AFTERNOON..BUT THIS VERY WELL COULD BE OVERDONE. BEST FORCING WILL
BE OFF TO EAST...BUT DEEP UPPER TROUGH REMAINING OVERHEAD AND STEEP
LOW LEVEL LAPSE RATES SHOULD KEEP AT LEAST ISOLATED SNOW SHOWERS AND
FLURRIES AROUND INTO EARLY WEDNESDAY AFTERNOON. STRONG LOW LEVEL
COLD ADVECTION WILL CONTINUE THROUGH WEDNESDAY NIGHT...WITH 925 MB
TEMPS IN THE MID MINUS 20SC BY EARLY THURSDAY. THUS DESPITE HIGH
PRESSURE REMAINING WELL NORTHWEST AND PRECLUDING RADIATIONAL
COOLING...SUBZERO LOWS ARE EXPECTED CWA WIDE...AND RELATIVELY
UNIFORM RANGING FROM MID MINUS SINGLE DIGITS TO AROUND 10 BELOW.
EVEN DOWNTOWN CHICAGO SHOULD FALL TO SEVERAL DEGREES BELOW ZERO.
WILL NEED A WIND CHILL ADVISORY FOR THE ENTIRE CWA WEDNESDAY
EVENING/NIGHT THROUGH THURSDAY MORNING...WITH LOWEST VALUES
RANGING FROM 20 TO 30 BELOW ZERO.
THERMAL TROUGH WILL ONLY SLOWLY DEPART TO THE NORTHEAST ON
THURSDAY...SO AFTER BITTERLY COLD START TO DAY...CONTINUE TO
FORECAST RECORD/NEAR RECORD LOW HIGH TEMPERATURES IN THE LOW TO MID
POSITIVE SINGLE DIGITS. SEE CLIMATE SECTION FOR ADDITIONAL DETAILS.
REGARDING LAKE EFFECT POTENTIAL ON WEDNESDAY INTO WEDNESDAY
NIGHT...GUIDANCE CONTINUES TO FOCUS MAINLY EAST OF PORTER COUNTY
WITH WNW BOUNDARY LAYER FLOW. HOWEVER...WITH EXTREME COLD AIR MASS
OVER RELATIVELY MILD LAKE WATERS...COULD STILL SEE SOME MINOR
ACCUMULATIONS IN NORTHEAST PORTER COUNTY IN LIGHT MULTIBAND SNOW
SHOWERS.
RC
&&
.LONG TERM...
320 PM CST
THURSDAY NIGHT THROUGH TUESDAY...
TO BE ISSUED SHORTLY.
RC
&&
.CLIMATE...
WHILE THE COLDEST AIR ALOFT ARRIVES WEDNESDAY...THE COLDEST SURFACE
TEMPERATURES MAY RESULT ON THURSDAY FEBRUARY 19TH...WHICH RIGHT NOW
APPEARS COULD JEOPARDIZE SOME RECORDS...ESPECIALLY THE LOW MAXS.
FEB 19TH
RECORD LOW RECORD LOW MAX
CHICAGO -7 (1936) 9 (1936)
ROCKFORD -16 (1979) 7 (1959)
MTF
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 20Z...
* GUSTY WLY-WNWLY WINDS TO 20 KT THROUGH LATE THIS AFTERNOON.
* OCNL -SHSN THROUGH SUNSET.
* POTENTIAL FOR A SHORT PERIOD OF MODERATE SNOW SHOWERS LATE
TONIGHT WITH PERIODS IFR VIS/MVFR CIGS POSSIBLE.
* GUSTY NWLY WINDS TO 25KT TOMORROW.
KREIN
//DISCUSSION...UPDATED 18Z...
A WEAK COLD FRONT HAS PUSHED THROUGH ALL OF THE TERMINALS...EXCEPT
GYY...AT ISSUANCE TIME. EXPECT THAT THE FRONT SHOULD PUSH PAST GYY
WITHIN THE NEXT HOURS OR SO. FOLLOWING THE FROPA...SCT SNOW
SHOWERS HAVE ENDED AND SKIES ARE IMPROVING TO VFR AND WINDS HAVE
SHIFTED TO GENERALLY NWLY. WITH INCREASED SUNSHINE AND POST FRONTAL
COLD ADVECTION...EXPECT GUSTS TO 20KT THROUGH THE AFTERNOON.
ANOTHER PERIOD OF LIGHT SNOW IS POSSIBLE TONIGHT AS A MID LEVEL
IMPULSE CROSSES THE REGION...AROUND THE SOUTHWESTERN PERIPHERY OF A
BROAD UPPER TROUGH COVERING THE ERN/CNTRL CONUS. SINCE THE AIRMASS
OVER THE REGION IS STILL RELATIVELY DRY...ANTICIPATE ONLY MINOR
ACCUMULATIONS...PERHAPS AROUND 1 INCH...BUT WITH WINDS LIKELY TO
REMAIN ABOVE 10KT THROUGH THE NIGHT...EXPECT THE MAIN IMPACT TO BE
REDUCED VISIBILITY...LIKELY DROPPING INTO IFR LEVELS. GIVEN SOME
UNCERTAINTY TO THE EXACT TIMING OF THE SYSTEM CROSSING THE
AREA...WILL MAINTAIN THE GOING PROB30 GROUP...BUT ANTICIPATE THAT
THIS WILL BE UPGRADED TO A TEMPO OR PREVAILING GROUP AS TIMING
BECOMES MORE CERTAIN. FOLLOWING THE PASSAGE OF AN ASSOCIATED SFC
COLD FRONT...VERY COLD AIR WILL FILTER IN ACROSS THE AREA AS
STRONG HIGH PRESSURE BUILDS OVER THE NRN/CNTRL PLAINS AND A WEAK
SFC LOW PRESSURE MOVES THROUGH THE ERN GREAT LAKES. A MODERATE
PRESSURE GRADIENT AND STRONG COLD ADVECTION WILL LEAD TO GUSTY
NWLY WINDS THOUGH THE DAY TOMORROW...WITH GUSTS TO 25KT OR
POSSIBLY HIGHER.
KREIN
//ORD AND MDW CONFIDENCE...UPDATED 20Z...
* MEDIUM TO HIGH CONFIDENCE IN WIND TRENDS THROUGH THE PERIOD.
* MEDIUM TO HIGH CONFIDENCE IN ANOTHER ROUND OF LIGHT SNOW LATE TONIGHT.
* MEDIUM CONFIDENCE IN TIMING AND DURATION OF REDUCED CIGS/VIS
ASSOCIATED WITH THE SNOW.
* LOW TO MEDIUM CONFIDENCE IN HOW LOW CIGS/VIS WILL DROP DURG
PERIODS OF SNOW.
KREIN
//OUTLOOK FOR ORD/MDW FOR 00Z THURSDAY-12Z TUESDAY...UPDATED 12Z...
WEDNESDAY NIGHT...VFR WITH WEST-NORTHWEST WINDS.
THURSDAY...MAINLY VFR. NORTHWEST WINDS.
FRIDAY...CHANCE OF SNOW. IFR POSSIBLE. GUSTY SOUTH WINDS.
SATURDAY...CHANCE OF SNOW. IFR POSSIBLE. SOUTHWEST WINDS BECOMING
NORTHWEST.
SUNDAY...MAINLY VFR. NORTH-NORTHEAST WINDS.
MONDAY...VFR. WESTERLY WINDS.
KJB
&&
.MARINE...
336 PM CST
WESTERLY WINDS IN PLACE LATE THIS AFTERNOON ARE EXPECTED TO BECOME
MORE NORTHERLY TONIGHT AS LOW PRESSURE DEPARTS TO THE EAST AND
HIGH PRESSURE BUILDS OVER THE CENTRAL PART OF THE US. SPEEDS WILL
ALSO INCREASE TONIGHT AS THE SURFACE GRADIENT TIGHTENS AND HAS
COLDER AIR CONTINUES TO SPILL SOUTH ACROSS THE REGION...WITH WINDS
TO 30 KT LIKELY. INCREASING WINDS WILL CONTINUE ON WEDNESDAY WITH
GALES LIKELY PRIMARILY ON THE SOUTHERN HALF OF THE
LAKE...ALTHOUGH....A SMALL WINDOW OF GALE FORCE GUSTS DO APPEAR
POSSIBLE ACROSS THE NORTH HALF WEDNESDAY AFTERNOON. SO HAVE ISSUED
A GALE WARNING FOR THE SOUTH HALF AS WELL AS A HEAVY FREEZING
SPRAY WARNING FOR WEDNESDAY INTO WEDNESDAY EVENING. NORTHWEST
WINDS WILL SLOWLY DIMINISH WEDNESDAY NIGHT INTO THURSDAY...BUT
WITH WINDS TO 30KT STILL LIKELY.
RODRIGUEZ
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...HEAVY FREEZING SPRAY WARNING...LMZ080-LMZ567-LMZ669-LMZ671-
LMZ673-LMZ675-LMZ777-LMZ779-LMZ868-LMZ870-LMZ872-LMZ874-
LMZ876-LMZ878...6 AM WEDNESDAY TO 9 PM WEDNESDAY.
GALE WARNING...LMZ080-LMZ567-LMZ669-LMZ671-LMZ673-LMZ675-LMZ777-
LMZ779-LMZ868-LMZ870-LMZ872-LMZ874-LMZ876-LMZ878...6 AM
WEDNESDAY TO 9 PM WEDNESDAY.
GALE WARNING...LMZ745...9 AM WEDNESDAY TO 6 PM WEDNESDAY.
SMALL CRAFT ADVISORY...LMZ740-LMZ741-LMZ742-LMZ743-LMZ744...9 AM
WEDNESDAY TO 6 PM WEDNESDAY.
&&
$$
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Area Forecast Discussion
NATIONAL WEATHER SERVICE LINCOLN IL
320 PM CST Tue Feb 17 2015
.SHORT TERM...(Tonight)
ISSUED AT 320 PM CST TUE FEB 17 2015
Slightly complicated forecast in the short term as the long wave
trof rotates around and through the region tonight, with a couple
shortwaves on satellite imagery. HRRR and RUC/RAPP both producing
more qpf with prev runs and clearly picking up on some snow showers
out to the west. NAM/GFS picking up on it, but mainly concentrating
on wave to the south. As a result, two additions to tonights
forecast...one with the southwest CWA in a line from roughly
Jacksonville to Springfield to Paris...potential for a few tenths of
snowfall. Up to an inch possible, but better chances will be to the
south, where the second change to the forecast is with the more
southerly wave...an inch/inch and a half are possible. Behind the
snow as morning approaches, the northwesterly winds will continue to
increase. Temperatures will mainly run slightly off the normal
diurnal curve as the cold air mass moves southward into the region.
By early morning hours, wind chills will drop to -10 to -15F NW of
the Illinois River Valley.
&&
.LONG TERM...(Wednesday through Tuesday)
ISSUED AT 320 PM CST TUE FEB 17 2015
Another reinforcing push of cold air will move into central Illinois
behind another pressure trough early Wednesday. Very cold arctic air
will result in highs only in the single digits with brisk northwest
winds 15-20 mph and gusts to around 30 mph. Went below MOS guidance
for highs Wed due to extreme variation from climatology and due to
snow cover over portions of the forecast area. As a result, wind
chill values will be below -15 F for much of the area northwest of
the Illinois River and have issued a wind chill advisory from 5 a.m.
to noon. Wind chill temperatures should be just above wind chill
criteria...-10 F or so for the afternoon, but still very cold. Winds
will settle down somewhat overnight Wednesday night causing
temperatures to drop below zero throughout central IL, but wind
chills look to drop to around -15 to -20 F and may need another wind
chill advisory.
Deep upper level trof shifts east of IL Thu night and Friday while
arctic high pressure also drifts east of IL across the Ohio river
valley Thu night and Fri morning. Temps will be slow to climb on
Friday due to mostly cloudy skies with highs in the low to mid 20s.
Have small chances of light snow Friday afternoon as moist warm
advection affects the region.
Extended models coming to better agreement on track of southern
stream storm system this weekend, with track of low passing the
southern tip of Illinois Saturday. Looks cold enough for mainly
light snow, though continue with a mix over southeast IL on Sat.
Have just slight chance of light snow Sunday and then dry across
area by Sunday evening. Highs in the low to mid 30s Sat cool off
again early next week on Sunday and Monday behind this storm
system.
&&
.AVIATION...(For the 18Z TAFS through 18Z Wednesday afternoon)
ISSUED AT 1148 AM CST TUE FEB 17 2015
Brief clearing behind the boundary this morning and northwesterly
winds setting up across the region. Northwesterly winds will
continue through tomorrow morning becoming brisk and gusty to
25 kts by mid morning. SC are expected to move in associated
with a small wave as well as develop over the FA this afternoon
and bring chance for flurries. More widespread threat for -SN
moving in just before midnight and spreading east into the morning
hours. Skies mainly VFR until the -SN and drop to MVFR between 05z
and 12z.
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
WIND CHILL ADVISORY from 5 AM to Noon CST Wednesday FOR
ILZ027>029-036-040.
&&
$$
SHORT TERM...HJS
LONG TERM...Onton
AVIATION...HJS
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
1144 AM CST TUE FEB 17 2015
.UPDATE...
1052 AM CST
SNOW SHOWERS HAVE LINGERED A BIT LONGER THAN EXPECTED OVER
PORTIONS OF NORTHERN IL AND NORTHWEST IN AS FORCING FROM ELONGATED
MIDLEVEL VORT MAX HAS TRANSLATED ACROSS THE AREA. SUPPRESSION ON
BACK SIDE OF WAVE WILL CUT OFF ONGOING SNOW SHOWER ACTIVITY FROM
NORTHWEST TO SOUTHEAST INTO EARLY AFTERNOON...SO HAVE TAILORED LOW
MEASURABLE POPS TO FOLLOW THIS TREND. BASED ON LATEST
RADAR...COULD STILL SEE VISIBILITY BRIEFLY BELOW 1 MILE AT TIMES
IN HEAVIER SNOW SHOWERS...BUT NOT EXPECTING MORE THAN A DUSTING TO
A FEW TENTHS OF AN INCH OF SNOW. ALSO ADJUSTED TEMPS AND DEWPOINTS
A BIT...WITH SLIGHTLY MILDER HIGHS RANGING FROM 20 TO 24 ALONG AND
EAST OF A CHICAGO TO STREATOR LINE. FINALLY...MADE SOME SKY GRID
ADJUSTMENTS TO ACCOUNT FOR CLEARER CONDITIONS IN WESTERN HALF OF
CWA.
THE SNOW SHOWER ACTIVITY THIS MORNING COULD BE A PREVIEW OF LATE
TONIGHT INTO WEDNESDAY MORNING AS A MUCH STRONGER PV ANOMALY
IMPACTS THE AREA. MODELS CONTINUE WITH VERY LOW QPF IN ARCTIC AIR
MASS...BUT EXPECTING POTENTIALLY MORE WIDESPREAD AND HEAVIER SNOW
SHOWERS DUE TO BETTER FORCING FROM STRONGER UPPER WAVE.
UPDATED GRIDS AND ZONES HAVE BEEN SENT.
RC
&&
.SHORT TERM...
301 AM CST
THROUGH WEDNESDAY...
EARLY MORNING WATER VAPOR IMAGERY SHOWS THE AMPLIFYING UPPER FLOW
PATTERN WHICH WILL BRING ANOTHER ROUND OF BITTERLY COLD AIR TO THE
AREA. A LARGE LONGWAVE TROUGH IS SPREAD ACROSS THE EASTERN TWO-
THIRDS OF NORTH AMERICA WHILE SHARP LONGWAVE RIDGING EXTENDS UP
THE WEST COAST. SEVERAL SUBTLE SHORTWAVES ARE EMBEDDED IN THE
NORTHERLY FLOW FROM NORTHERN CANADA TO THE CENTRAL PLAINS. THE
MAIN WAVE OF NOTE IS ONE THAT IS QUICKLY MOVING SOUTHWARD ACROSS
CENTRAL SASKATCHEWAN AND MANITOBA...AND WILL BRING THE PUSH OF
COLDEST AIR TOMORROW. IN THE NEAR TERM...A WAVE DROPPING
SOUTHEASTWARD FROM MINNESOTA WILL CROSS THE AREA EARLY THIS
MORNING. AT THE SURFACE...A COLD FRONT EXTENDS FROM LOW PRESSURE
OVER HUDSON BAY WITH A SECONDARY CIRCULATION OVER THE EASTERN U.P.
OF MICHIGAN. THE FRONT WILL CROSS THE AREA BY MID MORNING TURNING
WINDS NORTHWESTERLY. RADAR MOSAIC SHOWS LIGHT RETURNS ACROSS THE
AREA WHICH ARE PRODUCING SOME FLURRIES AND A LITTLE LIGHT SNOW.
BANDS OF LIGHT SNOW SHOWERS ARE APPROACHING IN CLOSER PROXIMITY TO
THE FRONT AND THE ASSOCIATED UPPER WAVE AND MAY RESULT IN SNOW
INTENSE ENOUGH TO LOWER VSBY TO A FEW MILES THANKS TO STEEP LOW
LEVEL LAPSE RATES ALLOWING FOR A CONVECTIVE COMPONENT. COVERAGE
WILL NOT BE THAT GREAT AND DURATION WILL BE SHORT BUT WILL WORK
LOW POPS THROUGH THE AREA THROUGH MID MORNING. H85 TEMPS FALL TO
-16 TO -20C BY LATE DAY WITH H92 TEMPS FROM -16 TO -18C YIELDING
HIGHS IN THE LOWER TEENS NORTH TO AROUND 20 SOUTH. THERE WILL NOT
BE MUCH IN THE WAY OF LARGE SCALE LIFT BY AFTERNOON WITH THE UPPER
TROUGH EXITING BUT LOW LEVEL LAPSE RATES AND CONTINUED CLOUD
COVER/MOISTURE MAY LEAD TO SOME FLURRY ACTIVITY THANKS TO THE
PRESENCE OF ICE CRYSTALS IN THE STEEP LAPSE RATE ZONE.
THE CENTRAL SASKATCHEWAN/MANITOBA TROUGH WORKS ACROSS THE AREA
TONIGHT. THIS TROUGH SHOULD BRING BETTER LARGE SCALE FORCING WITH IT
BUT ALSO ANOTHER ROUND OF STEEP LAPSE RATES WITH ANOTHER STRONG COLD
FRONT. AM CONCERNED THAT THERE WILL BE A HIGHER COVERAGE OF FAIRLY
INTENSE SNOW SHOWERS THAT ACCOMPANIES THE TROUGH/FRONT PASSAGE LATE
THIS EVENING AND OVERNIGHT. WITH A FAIRLY SHORT DURATION TO ANY
GIVEN SNOW SHOWER ACCUMULATION WOULD BE LIMITED BUT COULD FORESEE
GREATLY REDUCED VSBY IN THE SNOW SHOWERS THAT DO OCCUR WITH A QUICK
ACCUMULATION...NOT UNLIKE SOME OF THE SNOW SQUALLS THAT OCCURRED WITH
A FRONTAL PASSAGE OVER THE WEEKEND. AT THIS POINT OCCURRENCE LOOKS
TO END RIGHT AROUND THE START OF THE WEDNESDAY MORNING RUSH WHICH
ADDS TO THE CONCERN. WILL CONTINUE WITH SLIGHT AND LOW CHANCE POPS
FOR NOW BUT WILL PASS CONCERNS ALONG TO THE DAY SHIFT. STEEP LAPSE
RATES AND CONTINUED COLD ADVECTION MAY RESULT IN PERIODS OF FLURRIES
OR EVEN SOME ADDITIONAL LIGHT SNOW THROUGH MUCH OF WEDNESDAY. LAKE
EFFECT SNOW WILL SKIRT NORTHEAST PORTER COUNTY SO INTERMITTENT BOUTS
OF LIGHT SNOW WILL OCCUR WEDNESDAY. HIGH TEMPS WILL BE A BIT TRICKY
WITH DIFFERENCES IN THE TIMING OF THE ARRIVAL OF THE COLDEST AIR.
THE GFS REMAINS THE FASTEST WITH THE INFLUX OF H85 TEMPS OF -28C AND
H92 TEMPS OF -24C BY EARLY AFTERNOON...WHILE THE NAM/ECMWF ARE
SLOWER WITH THE ARRIVAL OF AIR THIS COLD UNTIL EVENING. LOCAL
H85/H92 CLIMO UTILIZING A SLOWER ARRIVAL OF THE COLDEST AIR SIDES
MORE WITH SOME OF THE BETTER PERFORMING GUIDANCE OF LATE SUGGESTING
HIGHS IN THE UPPER SINGLE DIGITS NORTHWEST TO THE LOWER TEENS
SOUTHEAST. THESE MAY OCCUR EARLY WITH FALLING TEMPS THROUGH THE DAY.
BASED ON GREATER SUPPORT FOR SLIGHTLY WARMER HIGHS...AT LEAST
EARLY...WILL NUDGE VALUES UP A FEW DEGREES. STEADY NORTHWEST WINDS
WILL KEEP TEMPS FROM RADIATING OUT WEDNESDAY NIGHT THOUGH THEY WILL
STILL FALL TO BETWEEN ABOUT 2 BELOW AND 10 BELOW. THE WINDS WILL
ALSO PUSH WIND CHILLS TO BETWEEN -20 AND -30 F INTO THURSDAY MORNING
SO A WIND CHILL ADVISORY WILL LIKELY BE NEEDED.
MDB
&&
.LONG TERM...
301 AM CST
THURSDAY THROUGH MONDAY...
HIGH PRESSURE WILL STRETCH FROM
MANITOBA TO THE LOWER MISSISSIPPI RIVER VALLEY THURSDAY MORNING AND
STEADILY SLIDE EASTWARD. WESTERN UPPER RIDGING WILL BREAK DOWN AND
BE PUSHED EASTWARD INTO THE AREA AHEAD OF A TROUGH THAT WILL BE
DROPPING SOUTHEAST ACROSS WESTERN CANADA. TIMING OF TEMP
MODIFICATION WILL AGAIN BE AN ISSUE WITH THE GFS BEING THE SLOWEST
ON THE ARRIVAL OF WARMING ALOFT. THE DIFFERENCES MAY BE MOOT AS THE
HIGH WILL BE PASSING OVERHEAD LEAVING WEAK LOW LEVEL FLOW AND WEAK
MIXING. WILL CONTINUE WITH HIGHS FROM ROUND 5 NORTH TO 10 SOUTH
THURSDAY. LAKE EFFECT SNOW CHANCES WILL CONTINUE ACROSS NORTHEAST
PORTER COUNTY THURSDAY BEFORE SUBSIDENCE STARTS TO LIMIT LAKE EFFECT
BY THURSDAY EVENING. THE PATTERN SHIFTS INTO THE WEEKEND WITH THE
BIG EASTERN TROUGH BEING KICKED OUT INTO THE ATLANTIC AND A MORE
ZONAL FLOW SETTING UP ACROSS MOST OF THE U.S. THE AFOREMENTIONED
WESTERN CANADA TROUGH WILL CONTINUE EASTWARD FRIDAY AND MAY BRING
SOME PRECIP TO THE REGION. ENERGY THEN DIGS INTO THE WESTERN U.S.
TRIGGERING SFC LOW DEVELOPMENT OVER TEXAS BY SATURDAY. THIS LOW WILL
RIDE NORTHEAST ALONG A BAROCLINIC ZONE INTO SUNDAY WITH GUIDANCE
CONTINUING TO BE AT ODDS WITH WHERE EXACTLY THE TRACK WILL SET
UP...THOUGH THE SIGNAL FOR THIS SYSTEM OCCURRING IS BECOMING MORE
CONSISTENT. WILL NEED TO KEEP AN EYE ON THIS AS IT WILL DICTATE POPS
OVER THE WEEKEND. WITH THE PATTERN SHIFT TEMPS WILL MODERATE INTO
THE UPPER 20S AND POSSIBLY LOWER 30S SATURDAY WITH COOLER READINGS
SUNDAY AND MONDAY AS ANOTHER STRONG HIGH PRESSURE SYSTEM WILL TAKE
OVER. LESS AMPLIFIED FLOW WILL BE IN PLACE SO THE COOL DOWN WILL NOT
BE AS NOTABLE WITH HIGHS LOOKING TO BE AROUND 20.
MDB
&&
.CLIMATE...
WHILE THE COLDEST AIR ALOFT ARRIVES WEDNESDAY...THE COLDEST SURFACE
TEMPERATURES MAY RESULT ON THURSDAY FEBRUARY 19TH...WHICH RIGHT NOW
APPEARS COULD JEOPARDIZE SOME RECORDS...ESPECIALLY THE LOW MAXS.
FEB 19TH
RECORD LOW RECORD LOW MAX
CHICAGO -7 (1936) 9 (1936)
ROCKFORD -16 (1979) 7 (1959)
MTF
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 18Z...
* GUSTY WLY-WNWLY WINDS TO 20 KT THROUGH LATE THIS AFTERNOON.
* POTENTIAL FOR A SHORT PERIOD OF MODERATE SNOW SHOWERS LATE
TONIGHT WITH PERIODS IFR VIS/MVFR CIGS POSSIBLE.
* GUSTY NWLY WINDS TO 25KT TOMORROW.
KREIN
//DISCUSSION...UPDATED 18Z...
A WEAK COLD FRONT HAS PUSHED THROUGH ALL OF THE TERMINALS...EXCEPT
GYY...AT ISSUANCE TIME. EXPECT THAT THE FRONT SHOULD PUSH PAST GYY
WITHIN THE NEXT HOURS OR SO. FOLLOWING THE FROPA...SCT SNOW
SHOWERS HAVE ENDED AND SKIES ARE IMPROVING TO VFR AND WINDS HAVE
SHIFTED TO GENERALLY NWLY. WITH INCREASED SUNSHINE AND POST FRONTAL
COLD ADVECTION...EXPECT GUSTS TO 20KT THROUGH THE AFTERNOON.
ANOTHER PERIOD OF LIGHT SNOW IS POSSIBLE TONIGHT AS A MID LEVEL
IMPULSE CROSSES THE REGION...AROUND THE SOUTHWESTERN PERIPHERY OF A
BROAD UPPER TROUGH COVERING THE ERN/CNTRL CONUS. SINCE THE AIRMASS
OVER THE REGION IS STILL RELATIVELY DRY...ANTICIPATE ONLY MINOR
ACCUMULATIONS...PERHAPS AROUND 1 INCH...BUT WITH WINDS LIKELY TO
REMAIN ABOVE 10KT THROUGH THE NIGHT...EXPECT THE MAIN IMPACT TO BE
REDUCED VISIBILITY...LIKELY DROPPING INTO IFR LEVELS. GIVEN SOME
UNCERTAINTY TO THE EXACT TIMING OF THE SYSTEM CROSSING THE
AREA...WILL MAINTAIN THE GOING PROB30 GROUP...BUT ANTICIPATE THAT
THIS WILL BE UPGRADED TO A TEMPO OR PREVAILING GROUP AS TIMING
BECOMES MORE CERTAIN. FOLLOWING THE PASSAGE OF AN ASSOCIATED SFC
COLD FRONT...VERY COLD AIR WILL FILTER IN ACROSS THE AREA AS
STRONG HIGH PRESSURE BUILDS OVER THE NRN/CNTRL PLAINS AND A WEAK
SFC LOW PRESSURE MOVES THROUGH THE ERN GREAT LAKES. A MODERATE
PRESSURE GRADIENT AND STRONG COLD ADVECTION WILL LEAD TO GUSTY
NWLY WINDS THOUGH THE DAY TOMORROW...WITH GUSTS TO 25KT OR
POSSIBLY HIGHER.
KREIN
//ORD AND MDW CONFIDENCE...UPDATED 18Z...
* MEDIUM TO HIGH CONFIDENCE IN WIND TRENDS THROUGH THE PERIOD.
* MEDIUM TO HIGH CONFIDENCE IN ANOTHER ROUND OF LIGHT SNOW LATE TONIGHT.
* MEDIUM CONFIDENCE IN TIMING AND DURATION OF REDUCED CIGS/VIS
ASSOCIATED WITH THE SNOW.
* LOW TO MEDIUM CONFIDENCE IN HOW LOW CIGS/VIS WILL DROP DURG
PERIODS OF SNOW.
KREIN
//OUTLOOK FOR ORD/MDW FOR 00Z THURSDAY-12Z TUESDAY...UPDATED 12Z...
WEDNESDAY NIGHT...VFR WITH WEST-NORTHWEST WINDS.
THURSDAY...MAINLY VFR. NORTHWEST WINDS.
FRIDAY...CHANCE OF SNOW. IFR POSSIBLE. GUSTY SOUTH WINDS.
SATURDAY...CHANCE OF SNOW. IFR POSSIBLE. SOUTHWEST WINDS BECOMING
NORTHWEST.
SUNDAY...MAINLY VFR. NORTH-NORTHEAST WINDS.
MONDAY...VFR. WESTERLY WINDS.
KJB
&&
.MARINE...
148 AM CST
A PERIOD OF STRONG NORTHWESTERLY WINDS WILL SET UP ACROSS THE LAKE
ON WEDNESDAY AS THE GRADIENT TIGHTENS IN RESPONSE TO THE APPROACH OF
AN ARCTIC SURFACE HIGH OVER THE NORTHERN PLAINS. IT APPEARS THESE
STRONG NORTHWEST WINDS WILL CONTINUE WEDNESDAY NIGHT...WITH A SOLID
30 KT OF WIND EXPECTED. IT ALSO APPEARS THAT SOME 35 KT GALES COULD
OCCUR AT TIMES ACROSS THE SOUTH END OF LAKE MICHIGAN DURING THIS
PERIOD. ALTHOUGH THIS APPEARS TO BE A MARGINAL EVENT FOR GALES...IF
ANY GOOD CONVERGENT BANDS OF LAKE EFFECT SNOW SET UP...THIS COULD
PRODUCE PERIODS OF LOCALLY STRONGER WINDS OVER SOUTHERN AND
EASTERN PORTIONS OF THE LAKE. THEREFORE...I HAVE OPTED TO GO
AHEAD WITH A GALE WATCH FOR WEDNESDAY AND WEDNESDAY NIGHT OVER
SOUTHERN LAKE MICHIGAN...EXCLUDING THE NEAR SHORE WATERS. I WILL
ALSO INCLUDE A HEAVY FREEZING SPRAY WATCH FOR THESE SAME AREAS DUE
TO THE VERY COLD AIRMASS EXPECTED CONCURRENTLY WITH THESE STRONG
WINDS.
WINDS WILL EASE BAY THURSDAY AS THE SURFACE RIDGE OF HIGH PRESSURE
BEGINS TO SHIFT OVER THE WESTERN LAKES REGION. HOWEVER...IT APPEARS
THAT WINDS WILL QUICKLY PICK UP OUT OF THE SOUTH BY FRIDAY AS
ANOTHER CLIPPER SYSTEM TRACKS ACROSS SOUTHERN CANADA. THIS COULD
RESULT IN 30 KT SOUTHERLY WINDS AND MORE FREEZING SPRAY LAKE-WIDE ON
FRIDAY.
KJB
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...GALE WATCH...LMZ080-LMZ567-LMZ669-LMZ671-LMZ673-LMZ675-LMZ777-
LMZ779-LMZ868-LMZ870-LMZ872-LMZ874-LMZ876-LMZ878...6 AM
WEDNESDAY TO 3 AM THURSDAY.
HEAVY FREEZING SPRAY WATCH...LMZ080-LMZ567-LMZ669-LMZ671-LMZ673-
LMZ675-LMZ777-LMZ779-LMZ868-LMZ870-LMZ872-LMZ874-LMZ876-
LMZ878...6 AM WEDNESDAY TO 3 AM THURSDAY.
&&
$$
VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)
FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/NWSCHICAGO
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WWW.YOUTUBE.COM/NWSCHICAGO
Area Forecast Discussion
NATIONAL WEATHER SERVICE LINCOLN IL
1055 AM CST Tue Feb 17 2015
.UPDATE...
ISSUED AT 1050 AM CST TUE FEB 17 2015
Cold front moving through today almost exiting the CWA with brief
clearing behind the boundary. More sc on its way behind the
boundary and expected to develop through the remainder of the
afternoon making the sunshine brief this morning. Cannot rule out
the flurries from the impending short wave and developing cloud
cover. Forecast doing pretty well in the shorter term. No major
adjustments expected in the short term for now, with the sole
exception the brief change in the sky grids before 20z.
&&
.SHORT TERM...(Today)
ISSUED AT 330 AM CST TUE FEB 17 2015
A shortwave will trigger scattered flurries early this morning
across a large portion of central and southeast IL. The back edge
of the band of clouds/flurries is approaching NW IL at 3 am, and
should progress from NW to SE across the area this morning. Will
keep a mention of flurries along that band of clouds as it
progresses across the area.
Even in the clearing behind the shortwave, forecast soundings show
enough residual low level moisture for clouds to redevelop in any
periods of sunshine. Will work a period of clearing in the NW
counties later this morning, but increase clouds again later in the
afternoon.
The short range models continue to show a fast moving wave just west
of IL triggering a band of light snow later this afternoon. As the
wave curves around the south end of IL, snow showers will begin to
develop just south of our counties toward sunset. Have stuck with
just flurries for the snow forecast, and will not carry PoPs for
measurable snow near that feature.
Clear skies and light winds in the areas with new snow cover has
allowed temps early this morning to drop significantly below
guidance. Robinson has reached -10F, Lawrenceville -5, and Mount
Carmel -4 at 3 am. Unless the SE areas see some sunshine early this
afternoon, their highs will likely be affected by the bitterly cold
start to the day. Will trim a few degrees from forecast highs in the
southeast, and remain closer to a MAV/MET blend farther north.
&&
.LONG TERM...(Tonight through Monday)
ISSUED AT 330 AM CST TUE FEB 17 2015
00Z models continue to dig a strong upper level trof into the
Midwest during midweek and usher in more arctic air into the region
with the coldest temps from Wed thru Thu. A wind chill advisory will
eventually be needed Wed night and Thu morning across central and
southeast IL for wind chills of 15-25 below zero.
A northern stream short wave that digs into the trof over IL/IN
tonight keeps most of its light snow just south of central IL CWA
though scattered flurries will likely occur tonight into Wed. 850 mb
temps drop to -25 to -27C by Wed evening and this to be another
frigid air mass with highs struggling to reach 10F both Wed and Thu.
Lows Tue night in the single digits, then drop into single digits
below zero Wed night and some areas near IN border could dip below
zero again Thu night. A secondary arctic cold front plows se through
central IL late tonight into Wed morning. Brisk nw winds behind this
cold front on Wed will already bring wind chills down to -15F or a
bit colder Wed morning over IL river valley especially nw of the
river and reaching near wind chill advisory criteria. Coldest wind
chills of 15-25 below zero will occur Wed night into Thu morning and
coldest readings over Knox and Stark counties.
Deep upper level trof shifts east of IL Thu night and Friday while
arctic high pressure also drifts east of IL across the Ohio river
valley Thu night and Fri morning. Temps will be slow to climb
however on Friday due to mostly cloudy skies with highs in the low to
mid 20s. Have small chances of light snow Friday afternoon sw
counties ahead of next short wave. Extended models still differ with
handling southern stream storm system this weekend. ECWMF model has
trended further south with it surface low from central IL down to
just south of IL Sat. While GFS has surface low near KY/TN border by
midnight Sat night. GEM model moves low across TN on Sat. Due to
difference in models and from previous runs, stayed close to
guidance pops which are trending upward in southeast IL Sat/Sat
night. Looks cold enough for mainly light snow, though do continue a
mix over southeast IL on Sat. Have just slight chance of light snow
Sunday and then dry across area by Sunday evening. Highs in the low
to mid 30s Sat cool off again early next week on Sunday and Monday
behind this storm system.
The Climate Prediction Center (CPC) day 8-14 outlook for Feb 24-Mar
2 has IL in greater than 60% chance of below normal temperatures and
greater than 40% chance of below normal precipitation. So winter
looks to hold on the next two weeks.
&&
.AVIATION...(For the 12Z TAFS through 12Z Wednesday morning)
ISSUED AT 558 AM CST TUE FEB 17 2015
Low VFR cigs and flurries will affect the TAF sites for a few
hours early this TAF period, under a weak surface trough. A brief
period of MVFR clouds could occur at BMI, but kept the prevailing
conditions VFR. The trough will slide east this morning, with some
clearing for a few hours behind it. HRRR and RAP output indicate
clouds will redevelop during the day as a cold front pushes SE
across the area. Flurries will be possible with that feature. A
strong 500mb vort max diving south tonight into the upper trough
axis will likely trigger MVFR clouds and widespread flurries or
snow showers. Have included prevailing light snow beginning around
06z tonight, but did not introduce any MVFR vis restrictions with
this TAF issuance.
W-SW winds early this morning will become northwest late this
morning, then increase this afternoon to 12-14kts sustained and
gusts to 22kt. Wind gusts will diminish this evening, but
sustained winds could remain around 10kt for much of the night as
the vigorous shortwave moves south into Illinois.
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...HJS
SHORT TERM...Shimon
LONG TERM...07
AVIATION...Shimon
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
758 AM CST TUE FEB 17 2015
.SHORT TERM...
301 AM CST
THROUGH WEDNESDAY...
EARLY MORNING WATER VAPOR IMAGERY SHOWS THE AMPLIFYING UPPER FLOW
PATTERN WHICH WILL BRING ANOTHER ROUND OF BITTERLY COLD AIR TO THE
AREA. A LARGE LONGWAVE TROUGH IS SPREAD ACROSS THE EASTERN TWO-
THIRDS OF NORTH AMERICA WHILE SHARP LONGWAVE RIDGING EXTENDS UP
THE WEST COAST. SEVERAL SUBTLE SHORTWAVES ARE EMBEDDED IN THE
NORTHERLY FLOW FROM NORTHERN CANADA TO THE CENTRAL PLAINS. THE
MAIN WAVE OF NOTE IS ONE THAT IS QUICKLY MOVING SOUTHWARD ACROSS
CENTRAL SASKATCHEWAN AND MANITOBA...AND WILL BRING THE PUSH OF
COLDEST AIR TOMORROW. IN THE NEAR TERM...A WAVE DROPPING
SOUTHEASTWARD FROM MINNESOTA WILL CROSS THE AREA EARLY THIS
MORNING. AT THE SURFACE...A COLD FRONT EXTENDS FROM LOW PRESSURE
OVER HUDSON BAY WITH A SECONDARY CIRCULATION OVER THE EASTERN U.P.
OF MICHIGAN. THE FRONT WILL CROSS THE AREA BY MID MORNING TURNING
WINDS NORTHWESTERLY. RADAR MOSAIC SHOWS LIGHT RETURNS ACROSS THE
AREA WHICH ARE PRODUCING SOME FLURRIES AND A LITTLE LIGHT SNOW.
BANDS OF LIGHT SNOW SHOWERS ARE APPROACHING IN CLOSER PROXIMITY TO
THE FRONT AND THE ASSOCIATED UPPER WAVE AND MAY RESULT IN SNOW
INTENSE ENOUGH TO LOWER VSBY TO A FEW MILES THANKS TO STEEP LOW
LEVEL LAPSE RATES ALLOWING FOR A CONVECTIVE COMPONENT. COVERAGE
WILL NOT BE THAT GREAT AND DURATION WILL BE SHORT BUT WILL WORK
LOW POPS THROUGH THE AREA THROUGH MID MORNING. H85 TEMPS FALL TO
-16 TO -20C BY LATE DAY WITH H92 TEMPS FROM -16 TO -18C YIELDING
HIGHS IN THE LOWER TEENS NORTH TO AROUND 20 SOUTH. THERE WILL NOT
BE MUCH IN THE WAY OF LARGE SCALE LIFT BY AFTERNOON WITH THE UPPER
TROUGH EXITING BUT LOW LEVEL LAPSE RATES AND CONTINUED CLOUD
COVER/MOISTURE MAY LEAD TO SOME FLURRY ACTIVITY THANKS TO THE
PRESENCE OF ICE CRYSTALS IN THE STEEP LAPSE RATE ZONE.
THE CENTRAL SASKATCHEWAN/MANITOBA TROUGH WORKS ACROSS THE AREA
TONIGHT. THIS TROUGH SHOULD BRING BETTER LARGE SCALE FORCING WITH IT
BUT ALSO ANOTHER ROUND OF STEEP LAPSE RATES WITH ANOTHER STRONG COLD
FRONT. AM CONCERNED THAT THERE WILL BE A HIGHER COVERAGE OF FAIRLY
INTENSE SNOW SHOWERS THAT ACCOMPANIES THE TROUGH/FRONT PASSAGE LATE
THIS EVENING AND OVERNIGHT. WITH A FAIRLY SHORT DURATION TO ANY
GIVEN SNOW SHOWER ACCUMULATION WOULD BE LIMITED BUT COULD FORESEE
GREATLY REDUCED VSBY IN THE SNOW SHOWERS THAT DO OCCUR WITH A QUICK
ACCUMULATION...NOT UNLIKE SOME OF THE SNOW SQUALLS THAT OCCURRED WITH
A FRONTAL PASSAGE OVER THE WEEKEND. AT THIS POINT OCCURRENCE LOOKS
TO END RIGHT AROUND THE START OF THE WEDNESDAY MORNING RUSH WHICH
ADDS TO THE CONCERN. WILL CONTINUE WITH SLIGHT AND LOW CHANCE POPS
FOR NOW BUT WILL PASS CONCERNS ALONG TO THE DAY SHIFT. STEEP LAPSE
RATES AND CONTINUED COLD ADVECTION MAY RESULT IN PERIODS OF FLURRIES
OR EVEN SOME ADDITIONAL LIGHT SNOW THROUGH MUCH OF WEDNESDAY. LAKE
EFFECT SNOW WILL SKIRT NORTHEAST PORTER COUNTY SO INTERMITTENT BOUTS
OF LIGHT SNOW WILL OCCUR WEDNESDAY. HIGH TEMPS WILL BE A BIT TRICKY
WITH DIFFERENCES IN THE TIMING OF THE ARRIVAL OF THE COLDEST AIR.
THE GFS REMAINS THE FASTEST WITH THE INFLUX OF H85 TEMPS OF -28C AND
H92 TEMPS OF -24C BY EARLY AFTERNOON...WHILE THE NAM/ECMWF ARE
SLOWER WITH THE ARRIVAL OF AIR THIS COLD UNTIL EVENING. LOCAL
H85/H92 CLIMO UTILIZING A SLOWER ARRIVAL OF THE COLDEST AIR SIDES
MORE WITH SOME OF THE BETTER PERFORMING GUIDANCE OF LATE SUGGESTING
HIGHS IN THE UPPER SINGLE DIGITS NORTHWEST TO THE LOWER TEENS
SOUTHEAST. THESE MAY OCCUR EARLY WITH FALLING TEMPS THROUGH THE DAY.
BASED ON GREATER SUPPORT FOR SLIGHTLY WARMER HIGHS...AT LEAST
EARLY...WILL NUDGE VALUES UP A FEW DEGREES. STEADY NORTHWEST WINDS
WILL KEEP TEMPS FROM RADIATING OUT WEDNESDAY NIGHT THOUGH THEY WILL
STILL FALL TO BETWEEN ABOUT 2 BELOW AND 10 BELOW. THE WINDS WILL
ALSO PUSH WIND CHILLS TO BETWEEN -20 AND -30 F INTO THURSDAY MORNING
SO A WIND CHILL ADVISORY WILL LIKELY BE NEEDED.
MDB
&&
.LONG TERM...
301 AM CST
THURSDAY THROUGH MONDAY...
HIGH PRESSURE WILL STRETCH FROM
MANITOBA TO THE LOWER MISSISSIPPI RIVER VALLEY THURSDAY MORNING AND
STEADILY SLIDE EASTWARD. WESTERN UPPER RIDGING WILL BREAK DOWN AND
BE PUSHED EASTWARD INTO THE AREA AHEAD OF A TROUGH THAT WILL BE
DROPPING SOUTHEAST ACROSS WESTERN CANADA. TIMING OF TEMP
MODIFICATION WILL AGAIN BE AN ISSUE WITH THE GFS BEING THE SLOWEST
ON THE ARRIVAL OF WARMING ALOFT. THE DIFFERENCES MAY BE MOOT AS THE
HIGH WILL BE PASSING OVERHEAD LEAVING WEAK LOW LEVEL FLOW AND WEAK
MIXING. WILL CONTINUE WITH HIGHS FROM ROUND 5 NORTH TO 10 SOUTH
THURSDAY. LAKE EFFECT SNOW CHANCES WILL CONTINUE ACROSS NORTHEAST
PORTER COUNTY THURSDAY BEFORE SUBSIDENCE STARTS TO LIMIT LAKE EFFECT
BY THURSDAY EVENING. THE PATTERN SHIFTS INTO THE WEEKEND WITH THE
BIG EASTERN TROUGH BEING KICKED OUT INTO THE ATLANTIC AND A MORE
ZONAL FLOW SETTING UP ACROSS MOST OF THE U.S. THE AFOREMENTIONED
WESTERN CANADA TROUGH WILL CONTINUE EASTWARD FRIDAY AND MAY BRING
SOME PRECIP TO THE REGION. ENERGY THEN DIGS INTO THE WESTERN U.S.
TRIGGERING SFC LOW DEVELOPMENT OVER TEXAS BY SATURDAY. THIS LOW WILL
RIDE NORTHEAST ALONG A BAROCLINIC ZONE INTO SUNDAY WITH GUIDANCE
CONTINUING TO BE AT ODDS WITH WHERE EXACTLY THE TRACK WILL SET
UP...THOUGH THE SIGNAL FOR THIS SYSTEM OCCURRING IS BECOMING MORE
CONSISTENT. WILL NEED TO KEEP AN EYE ON THIS AS IT WILL DICTATE POPS
OVER THE WEEKEND. WITH THE PATTERN SHIFT TEMPS WILL MODERATE INTO
THE UPPER 20S AND POSSIBLY LOWER 30S SATURDAY WITH COOLER READINGS
SUNDAY AND MONDAY AS ANOTHER STRONG HIGH PRESSURE SYSTEM WILL TAKE
OVER. LESS AMPLIFIED FLOW WILL BE IN PLACE SO THE COOL DOWN WILL NOT
BE AS NOTABLE WITH HIGHS LOOKING TO BE AROUND 20.
MDB
&&
.CLIMATE...
WHILE THE COLDEST AIR ALOFT ARRIVES WEDNESDAY...THE COLDEST SURFACE
TEMPERATURES MAY RESULT ON THURSDAY FEBRUARY 19TH...WHICH RIGHT NOW
APPEARS COULD JEOPARDIZE SOME RECORDS...ESPECIALLY THE LOW MAXS.
FEB 19TH
RECORD LOW RECORD LOW MAX
CHICAGO -7 (1936) 9 (1936)
ROCKFORD -16 (1979) 7 (1959)
MTF
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 14Z...
* A FEW LINGERING SNOW SHOWERS EARLY THIS MORNING THROUGH AROUND
16 UTC...POSSIBLE PERIODS OF LOW MVFR CIGS/VIS.
* POTENTIAL FOR A SHORT PERIOD OF HEAVIER SNOW SHOWERS LATE TONIGHT
WITH IFR POSSIBLE.
KREIN
//DISCUSSION...UPDATED 12Z...
A COLD FRONT IS IN THE PROCESS OF MOVING ACROSS NORTHERN ILLINOIS.
ONCE THIS FRONT PASSES WE WILL SEE A QUICK END TO THE LIGHT SNOW
SHOWERS AND FLURRIES FOR A PERIOD. WINDS WILL TREND TOWARDS A WEST-
NORTHWEST DIRECTION AROUND 290 DEGREES WITH SOME LOW END GUSTS UP
AROUND 18 KT POSSIBLE AT TIMES THROUGH THE DAY.
LATER TODAY NIGHT A STRONGER ATMOSPHERIC DISTURBANCE IS EXPECTED TO
MOVE OVER THE AREA. AS THIS DOES SO...A PERIOD OF HEAVIER SNOW
SHOWERS COULD OCCUR...AND THIS COULD RESULT IN REDUCED
VISIBILITIES AND SOME MINOR SNOW ACCUMULATIONS. AT THIS TIME IT
APPEARS THE BEST POTENTIAL WOULD COME AFTER 06 UTC WEDNESDAY
MORNING AND LAST THROUGH THE PREDAWN HOURS OF WEDNESDAY MORNING. I
HAVE CONTINUED THE PROB 30 MENTION OF THIS AT KORD AND ADDED IN
FOR THE OTHER TERMINALS UNTIL A MORE PRECISE TIMING CAN BE IRONED
OUT.
KJB
//ORD AND MDW CONFIDENCE...UPDATED 14Z...
* MEDIUM TO HIGH CONFIDENCE IN OCNL MVFR CIGS/VIS WITH LINGERING
SNOW SHOWERS THIS MORNING.
* MEDIUM TO HIGH CONFIDENCE IN ENDING TIME OF SNOW SHOWERS THIS
MORNING.
* LOW TO MEDIUM ON EXTENT OF SNOW SHOWERS LATER TONIGHT.
KJB
//OUTLOOK FOR ORD/MDW FOR 00Z THURSDAY-12Z TUESDAY...UPDATED 12Z...
WEDNESDAY NIGHT...VFR WITH WEST-NORTHWEST WINDS.
THURSDAY...MAINLY VFR. NORTHWEST WINDS.
FRIDAY...CHANCE OF SNOW. IFR POSSIBLE. GUSTY SOUTH WINDS.
SATURDAY...CHANCE OF SNOW. IFR POSSIBLE. SOUTHWEST WINDS BECOMING
NORTHWEST.
SUNDAY...MAINLY VFR. NORTH-NORTHEAST WINDS.
MONDAY...VFR. WESTERLY WINDS.
KJB
&&
.MARINE...
148 AM CST
A PERIOD OF STRONG NORTHWESTERLY WINDS WILL SET UP ACROSS THE LAKE
ON WEDNESDAY AS THE GRADIENT TIGHTENS IN RESPONSE TO THE APPROACH OF
AN ARCTIC SURFACE HIGH OVER THE NORTHERN PLAINS. IT APPEARS THESE
STRONG NORTHWEST WINDS WILL CONTINUE WEDNESDAY NIGHT...WITH A SOLID
30 KT OF WIND EXPECTED. IT ALSO APPEARS THAT SOME 35 KT GALES COULD
OCCUR AT TIMES ACROSS THE SOUTH END OF LAKE MICHIGAN DURING THIS
PERIOD. ALTHOUGH THIS APPEARS TO BE A MARGINAL EVENT FOR GALES...IF
ANY GOOD CONVERGENT BANDS OF LAKE EFFECT SNOW SET UP...THIS COULD
PRODUCE PERIODS OF LOCALLY STRONGER WINDS OVER SOUTHERN AND
EASTERN PORTIONS OF THE LAKE. THEREFORE...I HAVE OPTED TO GO
AHEAD WITH A GALE WATCH FOR WEDNESDAY AND WEDNESDAY NIGHT OVER
SOUTHERN LAKE MICHIGAN...EXCLUDING THE NEAR SHORE WATERS. I WILL
ALSO INCLUDE A HEAVY FREEZING SPRAY WATCH FOR THESE SAME AREAS DUE
TO THE VERY COLD AIRMASS EXPECTED CONCURRENTLY WITH THESE STRONG
WINDS.
WINDS WILL EASE BAY THURSDAY AS THE SURFACE RIDGE OF HIGH PRESSURE
BEGINS TO SHIFT OVER THE WESTERN LAKES REGION. HOWEVER...IT APPEARS
THAT WINDS WILL QUICKLY PICK UP OUT OF THE SOUTH BY FRIDAY AS
ANOTHER CLIPPER SYSTEM TRACKS ACROSS SOUTHERN CANADA. THIS COULD
RESULT IN 30 KT SOUTHERLY WINDS AND MORE FREEZING SPRAY LAKE-WIDE ON
FRIDAY.
KJB
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...GALE WATCH...LMZ080-LMZ567-LMZ669-LMZ671-LMZ673-LMZ675-LMZ777-
LMZ779-LMZ868-LMZ870-LMZ872-LMZ874-LMZ876-LMZ878...6 AM
WEDNESDAY TO 3 AM THURSDAY.
HEAVY FREEZING SPRAY WATCH...LMZ080-LMZ567-LMZ669-LMZ671-LMZ673-
LMZ675-LMZ777-LMZ779-LMZ868-LMZ870-LMZ872-LMZ874-LMZ876-
LMZ878...6 AM WEDNESDAY TO 3 AM THURSDAY.
&&
$$
VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)
FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
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Area Forecast Discussion
NATIONAL WEATHER SERVICE LINCOLN IL
558 AM CST Tue Feb 17 2015
.SHORT TERM...(Today)
ISSUED AT 330 AM CST TUE FEB 17 2015
A shortwave will trigger scattered flurries early this morning
across a large portion of central and southeast IL. The back edge
of the band of clouds/flurries is approaching NW IL at 3 am, and
should progress from NW to SE across the area this morning. Will
keep a mention of flurries along that band of clouds as it
progresses across the area.
Even in the clearing behind the shortwave, forecast soundings show
enough residual low level moisture for clouds to redevelop in any
periods of sunshine. Will work a period of clearing in the NW
counties later this morning, but increase clouds again later in the
afternoon.
The short range models continue to show a fast moving wave just west
of IL triggering a band of light snow later this afternoon. As the
wave curves around the south end of IL, snow showers will begin to
develop just south of our counties toward sunset. Have stuck with
just flurries for the snow forecast, and will not carry PoPs for
measurable snow near that feature.
Clear skies and light winds in the areas with new snow cover has
allowed temps early this morning to drop significantly below
guidance. Robinson has reached -10F, Lawrenceville -5, and Mount
Carmel -4 at 3 am. Unless the SE areas see some sunshine early this
afternoon, their highs will likely be affected by the bitterly cold
start to the day. Will trim a few degrees from forecast highs in the
southeast, and remain closer to a MAV/MET blend farther north.
&&
.LONG TERM...(Tonight through Monday)
ISSUED AT 330 AM CST TUE FEB 17 2015
00Z models continue to dig a strong upper level trof into the
Midwest during midweek and usher in more arctic air into the region
with the coldest temps from Wed thru Thu. A wind chill advisory will
eventually be needed Wed night and Thu morning across central and
southeast IL for wind chills of 15-25 below zero.
A northern stream short wave that digs into the trof over IL/IN
tonight keeps most of its light snow just south of central IL CWA
though scattered flurries will likely occur tonight into Wed. 850 mb
temps drop to -25 to -27C by Wed evening and this to be another
frigid air mass with highs struggling to reach 10F both Wed and Thu.
Lows Tue night in the single digits, then drop into single digits
below zero Wed night and some areas near IN border could dip below
zero again Thu night. A secondary arctic cold front plows se through
central IL late tonight into Wed morning. Brisk nw winds behind this
cold front on Wed will already bring wind chills down to -15F or a
bit colder Wed morning over IL river valley especially nw of the
river and reaching near wind chill advisory criteria. Coldest wind
chills of 15-25 below zero will occur Wed night into Thu morning and
coldest readings over Knox and Stark counties.
Deep upper level trof shifts east of IL Thu night and Friday while
arctic high pressure also drifts east of IL across the Ohio river
valley Thu night and Fri morning. Temps will be slow to climb
however on Friday due to mostly cloudy skies with highs in the low to
mid 20s. Have small chances of light snow Friday afternoon sw
counties ahead of next short wave. Extended models still differ with
handling southern stream storm system this weekend. ECWMF model has
trended further south with it surface low from central IL down to
just south of IL Sat. While GFS has surface low near KY/TN border by
midnight Sat night. GEM model moves low across TN on Sat. Due to
difference in models and from previous runs, stayed close to
guidance pops which are trending upward in southeast IL Sat/Sat
night. Looks cold enough for mainly light snow, though do continue a
mix over southeast IL on Sat. Have just slight chance of light snow
Sunday and then dry across area by Sunday evening. Highs in the low
to mid 30s Sat cool off again early next week on Sunday and Monday
behind this storm system.
The Climate Prediction Center (CPC) day 8-14 outlook for Feb 24-Mar
2 has IL in greater than 60% chance of below normal temperatures and
greater than 40% chance of below normal precipitation. So winter
looks to hold on the next two weeks.
&&
.AVIATION...(For the 12Z TAFS through 12Z Wednesday morning)
ISSUED AT 558 AM CST TUE FEB 17 2015
Low VFR cigs and flurries will affect the TAF sites for a few
hours early this TAF period, under a weak surface trough. A brief
period of MVFR clouds could occur at BMI, but kept the prevailing
conditions VFR. The trough will slide east this morning, with some
clearing for a few hours behind it. HRRR and RAP output indicate
clouds will redevelop during the day as a cold front pushes SE
across the area. Flurries will be possible with that feature. A
strong 500mb vort max diving south tonight into the upper trough
axis will likely trigger MVFR clouds and widespread flurries or
snow showers. Have included prevailing light snow beginning around
06z tonight, but did not introduce any MVFR vis restrictions with
this TAF issuance.
W-SW winds early this morning will become northwest late this
morning, then increase this afternoon to 12-14kts sustained and
gusts to 22kt. Wind gusts will diminish this evening, but
sustained winds could remain around 10kt for much of the night as
the vigorous shortwave moves south into Illinois.
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...Shimon
LONG TERM...07
AVIATION...Shimon
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
507 AM CST TUE FEB 17 2015
.SHORT TERM...
301 AM CST
THROUGH WEDNESDAY...
EARLY MORNING WATER VAPOR IMAGERY SHOWS THE AMPLIFYING UPPER FLOW
PATTERN WHICH WILL BRING ANOTHER ROUND OF BITTERLY COLD AIR TO THE
AREA. A LARGE LONGWAVE TROUGH IS SPREAD ACROSS THE EASTERN TWO-
THIRDS OF NORTH AMERICA WHILE SHARP LONGWAVE RIDGING EXTENDS UP
THE WEST COAST. SEVERAL SUBTLE SHORTWAVES ARE EMBEDDED IN THE
NORTHERLY FLOW FROM NORTHERN CANADA TO THE CENTRAL PLAINS. THE
MAIN WAVE OF NOTE IS ONE THAT IS QUICKLY MOVING SOUTHWARD ACROSS
CENTRAL SASKATCHEWAN AND MANITOBA...AND WILL BRING THE PUSH OF
COLDEST AIR TOMORROW. IN THE NEAR TERM...A WAVE DROPPING
SOUTHEASTWARD FROM MINNESOTA WILL CROSS THE AREA EARLY THIS
MORNING. AT THE SURFACE...A COLD FRONT EXTENDS FROM LOW PRESSURE
OVER HUDSON BAY WITH A SECONDARY CIRCULATION OVER THE EASTERN U.P.
OF MICHIGAN. THE FRONT WILL CROSS THE AREA BY MID MORNING TURNING
WINDS NORTHWESTERLY. RADAR MOSAIC SHOWS LIGHT RETURNS ACROSS THE
AREA WHICH ARE PRODUCING SOME FLURRIES AND A LITTLE LIGHT SNOW.
BANDS OF LIGHT SNOW SHOWERS ARE APPROACHING IN CLOSER PROXIMITY TO
THE FRONT AND THE ASSOCIATED UPPER WAVE AND MAY RESULT IN SNOW
INTENSE ENOUGH TO LOWER VSBY TO A FEW MILES THANKS TO STEEP LOW
LEVEL LAPSE RATES ALLOWING FOR A CONVECTIVE COMPONENT. COVERAGE
WILL NOT BE THAT GREAT AND DURATION WILL BE SHORT BUT WILL WORK
LOW POPS THROUGH THE AREA THROUGH MID MORNING. H85 TEMPS FALL TO
-16 TO -20C BY LATE DAY WITH H92 TEMPS FROM -16 TO -18C YIELDING
HIGHS IN THE LOWER TEENS NORTH TO AROUND 20 SOUTH. THERE WILL NOT
BE MUCH IN THE WAY OF LARGE SCALE LIFT BY AFTERNOON WITH THE UPPER
TROUGH EXITING BUT LOW LEVEL LAPSE RATES AND CONTINUED CLOUD
COVER/MOISTURE MAY LEAD TO SOME FLURRY ACTIVITY THANKS TO THE
PRESENCE OF ICE CRYSTALS IN THE STEEP LAPSE RATE ZONE.
THE CENTRAL SASKATCHEWAN/MANITOBA TROUGH WORKS ACROSS THE AREA
TONIGHT. THIS TROUGH SHOULD BRING BETTER LARGE SCALE FORCING WITH IT
BUT ALSO ANOTHER ROUND OF STEEP LAPSE RATES WITH ANOTHER STRONG COLD
FRONT. AM CONCERNED THAT THERE WILL BE A HIGHER COVERAGE OF FAIRLY
INTENSE SNOW SHOWERS THAT ACCOMPANIES THE TROUGH/FRONT PASSAGE LATE
THIS EVENING AND OVERNIGHT. WITH A FAIRLY SHORT DURATION TO ANY
GIVEN SNOW SHOWER ACCUMULATION WOULD BE LIMITED BUT COULD FORESEE
GREATLY REDUCED VSBY IN THE SNOW SHOWERS THAT DO OCCUR WITH A QUICK
ACCUMULATION...NOT UNLIKE SOME OF THE SNOW SQUALLS THAT OCCURRED WITH
A FRONTAL PASSAGE OVER THE WEEKEND. AT THIS POINT OCCURRENCE LOOKS
TO END RIGHT AROUND THE START OF THE WEDNESDAY MORNING RUSH WHICH
ADDS TO THE CONCERN. WILL CONTINUE WITH SLIGHT AND LOW CHANCE POPS
FOR NOW BUT WILL PASS CONCERNS ALONG TO THE DAY SHIFT. STEEP LAPSE
RATES AND CONTINUED COLD ADVECTION MAY RESULT IN PERIODS OF FLURRIES
OR EVEN SOME ADDITIONAL LIGHT SNOW THROUGH MUCH OF WEDNESDAY. LAKE
EFFECT SNOW WILL SKIRT NORTHEAST PORTER COUNTY SO INTERMITTENT BOUTS
OF LIGHT SNOW WILL OCCUR WEDNESDAY. HIGH TEMPS WILL BE A BIT TRICKY
WITH DIFFERENCES IN THE TIMING OF THE ARRIVAL OF THE COLDEST AIR.
THE GFS REMAINS THE FASTEST WITH THE INFLUX OF H85 TEMPS OF -28C AND
H92 TEMPS OF -24C BY EARLY AFTERNOON...WHILE THE NAM/ECMWF ARE
SLOWER WITH THE ARRIVAL OF AIR THIS COLD UNTIL EVENING. LOCAL
H85/H92 CLIMO UTILIZING A SLOWER ARRIVAL OF THE COLDEST AIR SIDES
MORE WITH SOME OF THE BETTER PERFORMING GUIDANCE OF LATE SUGGESTING
HIGHS IN THE UPPER SINGLE DIGITS NORTHWEST TO THE LOWER TEENS
SOUTHEAST. THESE MAY OCCUR EARLY WITH FALLING TEMPS THROUGH THE DAY.
BASED ON GREATER SUPPORT FOR SLIGHTLY WARMER HIGHS...AT LEAST
EARLY...WILL NUDGE VALUES UP A FEW DEGREES. STEADY NORTHWEST WINDS
WILL KEEP TEMPS FROM RADIATING OUT WEDNESDAY NIGHT THOUGH THEY WILL
STILL FALL TO BETWEEN ABOUT 2 BELOW AND 10 BELOW. THE WINDS WILL
ALSO PUSH WIND CHILLS TO BETWEEN -20 AND -30 F INTO THURSDAY MORNING
SO A WIND CHILL ADVISORY WILL LIKELY BE NEEDED.
MDB
&&
.LONG TERM...
301 AM CST
THURSDAY THROUGH MONDAY...
HIGH PRESSURE WILL STRETCH FROM
MANITOBA TO THE LOWER MISSISSIPPI RIVER VALLEY THURSDAY MORNING AND
STEADILY SLIDE EASTWARD. WESTERN UPPER RIDGING WILL BREAK DOWN AND
BE PUSHED EASTWARD INTO THE AREA AHEAD OF A TROUGH THAT WILL BE
DROPPING SOUTHEAST ACROSS WESTERN CANADA. TIMING OF TEMP
MODIFICATION WILL AGAIN BE AN ISSUE WITH THE GFS BEING THE SLOWEST
ON THE ARRIVAL OF WARMING ALOFT. THE DIFFERENCES MAY BE MOOT AS THE
HIGH WILL BE PASSING OVERHEAD LEAVING WEAK LOW LEVEL FLOW AND WEAK
MIXING. WILL CONTINUE WITH HIGHS FROM ROUND 5 NORTH TO 10 SOUTH
THURSDAY. LAKE EFFECT SNOW CHANCES WILL CONTINUE ACROSS NORTHEAST
PORTER COUNTY THURSDAY BEFORE SUBSIDENCE STARTS TO LIMIT LAKE EFFECT
BY THURSDAY EVENING. THE PATTERN SHIFTS INTO THE WEEKEND WITH THE
BIG EASTERN TROUGH BEING KICKED OUT INTO THE ATLANTIC AND A MORE
ZONAL FLOW SETTING UP ACROSS MOST OF THE U.S. THE AFOREMENTIONED
WESTERN CANADA TROUGH WILL CONTINUE EASTWARD FRIDAY AND MAY BRING
SOME PRECIP TO THE REGION. ENERGY THEN DIGS INTO THE WESTERN U.S.
TRIGGERING SFC LOW DEVELOPMENT OVER TEXAS BY SATURDAY. THIS LOW WILL
RIDE NORTHEAST ALONG A BAROCLINIC ZONE INTO SUNDAY WITH GUIDANCE
CONTINUING TO BE AT ODDS WITH WHERE EXACTLY THE TRACK WILL SET
UP...THOUGH THE SIGNAL FOR THIS SYSTEM OCCURRING IS BECOMING MORE
CONSISTENT. WILL NEED TO KEEP AN EYE ON THIS AS IT WILL DICTATE POPS
OVER THE WEEKEND. WITH THE PATTERN SHIFT TEMPS WILL MODERATE INTO
THE UPPER 20S AND POSSIBLY LOWER 30S SATURDAY WITH COOLER READINGS
SUNDAY AND MONDAY AS ANOTHER STRONG HIGH PRESSURE SYSTEM WILL TAKE
OVER. LESS AMPLIFIED FLOW WILL BE IN PLACE SO THE COOL DOWN WILL NOT
BE AS NOTABLE WITH HIGHS LOOKING TO BE AROUND 20.
MDB
&&
.CLIMATE...
WHILE THE COLDEST AIR ALOFT ARRIVES WEDNESDAY...THE COLDEST SURFACE
TEMPERATURES MAY RESULT ON THURSDAY FEBRUARY 19TH...WHICH RIGHT NOW
APPEARS COULD JEOPARDIZE SOME RECORDS...ESPECIALLY THE LOW MAXS.
FEB 19TH
RECORD LOW RECORD LOW MAX
CHICAGO -7 (1936) 9 (1936)
ROCKFORD -16 (1979) 7 (1959)
MTF
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 12Z...
* POTENTIAL FOR A SHORT PERIOD OF HEAVIER SNOW SHOWERS LATE TONIGHT
WITH IFR POSSIBLE.
KJB
//DISCUSSION...UPDATED 12Z...
A COLD FRONT IS IN THE PROCESS OF MOVING ACROSS NORTHERN ILLINOIS.
ONCE THIS FRONT PASSES WE WILL SEE A QUICK END TO THE LIGHT SNOW
SHOWERS AND FLURRIES FOR A PERIOD. WINDS WILL TREND TOWARDS A WEST-
NORTHWEST DIRECTION AROUND 290 DEGREES WITH SOME LOW END GUSTS UP
AROUND 18 KT POSSIBLE AT TIMES THROUGH THE DAY.
LATER TODAY NIGHT A STRONGER ATMOSPHERIC DISTURBANCE IS EXPECTED TO
MOVE OVER THE AREA. AS THIS DOES SO...A PERIOD OF HEAVIER SNOW
SHOWERS COULD OCCUR...AND THIS COULD RESULT IN REDUCED
VISIBILITIES AND SOME MINOR SNOW ACCUMULATIONS. AT THIS TIME IT
APPEARS THE BEST POTENTIAL WOULD COME AFTER 06 UTC WEDNESDAY
MORNING AND LAST THROUGH THE PREDAWN HOURS OF WEDNESDAY MORNING. I
HAVE CONTINUED THE PROB 30 MENTION OF THIS AT KORD AND ADDED IN
FOR THE OTHER TERMINALS UNTIL A MORE PRECISE TIMING CAN BE IRONED
OUT.
KJB
//ORD AND MDW CONFIDENCE...UPDATED 12Z...
* LOW TO MEDIUM ON EXTENT OF SNOW SHOWERS LATER TONIGHT.
KJB
//OUTLOOK FOR ORD/MDW FOR 00Z THURSDAY-12Z TUESDAY...UPDATED 12Z...
WEDNESDAY NIGHT...VFR WITH WEST-NORTHWEST WINDS.
THURSDAY...MAINLY VFR. NORTHWEST WINDS.
FRIDAY...CHANCE OF SNOW. IFR POSSIBLE. GUSTY SOUTH WINDS.
SATURDAY...CHANCE OF SNOW. IFR POSSIBLE. SOUTHWEST WINDS BECOMING
NORTHWEST.
SUNDAY...MAINLY VFR. NORTH-NORTHEAST WINDS.
MONDAY...VFR. WESTERLY WINDS.
KJB
&&
.MARINE...
148 AM CST
A PERIOD OF STRONG NORTHWESTERLY WINDS WILL SET UP ACROSS THE LAKE
ON WEDNESDAY AS THE GRADIENT TIGHTENS IN RESPONSE TO THE APPROACH OF
AN ARCTIC SURFACE HIGH OVER THE NORTHERN PLAINS. IT APPEARS THESE
STRONG NORTHWEST WINDS WILL CONTINUE WEDNESDAY NIGHT...WITH A SOLID
30 KT OF WIND EXPECTED. IT ALSO APPEARS THAT SOME 35 KT GALES COULD
OCCUR AT TIMES ACROSS THE SOUTH END OF LAKE MICHIGAN DURING THIS
PERIOD. ALTHOUGH THIS APPEARS TO BE A MARGINAL EVENT FOR GALES...IF
ANY GOOD CONVERGENT BANDS OF LAKE EFFECT SNOW SET UP...THIS COULD
PRODUCE PERIODS OF LOCALLY STRONGER WINDS OVER SOUTHERN AND
EASTERN PORTIONS OF THE LAKE. THEREFORE...I HAVE OPTED TO GO
AHEAD WITH A GALE WATCH FOR WEDNESDAY AND WEDNESDAY NIGHT OVER
SOUTHERN LAKE MICHIGAN...EXCLUDING THE NEAR SHORE WATERS. I WILL
ALSO INCLUDE A HEAVY FREEZING SPRAY WATCH FOR THESE SAME AREAS DUE
TO THE VERY COLD AIRMASS EXPECTED CONCURRENTLY WITH THESE STRONG
WINDS.
WINDS WILL EASE BAY THURSDAY AS THE SURFACE RIDGE OF HIGH PRESSURE
BEGINS TO SHIFT OVER THE WESTERN LAKES REGION. HOWEVER...IT APPEARS
THAT WINDS WILL QUICKLY PICK UP OUT OF THE SOUTH BY FRIDAY AS
ANOTHER CLIPPER SYSTEM TRACKS ACROSS SOUTHERN CANADA. THIS COULD
RESULT IN 30 KT SOUTHERLY WINDS AND MORE FREEZING SPRAY LAKE-WIDE ON
FRIDAY.
KJB
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...GALE WATCH...LMZ080-LMZ567-LMZ669-LMZ671-LMZ673-LMZ675-LMZ777-
LMZ779-LMZ868-LMZ870-LMZ872-LMZ874-LMZ876-LMZ878...6 AM
WEDNESDAY TO 3 AM THURSDAY.
HEAVY FREEZING SPRAY WATCH...LMZ080-LMZ567-LMZ669-LMZ671-LMZ673-
LMZ675-LMZ777-LMZ779-LMZ868-LMZ870-LMZ872-LMZ874-LMZ876-
LMZ878...6 AM WEDNESDAY TO 3 AM THURSDAY.
&&
$$
VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)
FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
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Area Forecast Discussion
NATIONAL WEATHER SERVICE LINCOLN IL
331 AM CST Tue Feb 17 2015
.SHORT TERM...(Today)
ISSUED AT 330 AM CST TUE FEB 17 2015
A shortwave will trigger scattered flurries early this morning
across a large portion of central and southeast IL. The back edge
of the band of clouds/flurries is approaching NW IL at 3 am, and
should progress from NW to SE across the area this morning. Will
keep a mention of flurries along that band of clouds as it
progresses across the area.
Even in the clearing behind the shortwave, forecast soundings show
enough residual low level moisture for clouds to redevelop in any
periods of sunshine. Will work a period of clearing in the NW
counties later this morning, but increase clouds again later in the
afternoon.
The short range models continue to show a fast moving wave just west
of IL triggering a band of light snow later this afternoon. As the
wave curves around the south end of IL, snow showers will begin to
develop just south of our counties toward sunset. Have stuck with
just flurries for the snow forecast, and will not carry PoPs for
measurable snow near that feature.
Clear skies and light winds in the areas with new snow cover has
allowed temps early this morning to drop significantly below
guidance. Robinson has reached -10F, Lawrenceville -5, and Mount
Carmel -4 at 3 am. Unless the SE areas see some sunshine early this
afternoon, their highs will likely be affected by the bitterly cold
start to the day. Will trim a few degrees from forecast highs in the
southeast, and remain closer to a MAV/MET blend farther north.
&&
.LONG TERM...(Tonight through Monday)
ISSUED AT 330 AM CST TUE FEB 17 2015
00Z models continue to dig a strong upper level trof into the
Midwest during midweek and usher in more arctic air into the region
with the coldest temps from Wed thru Thu. A wind chill advisory will
eventually be needed Wed night and Thu morning across central and
southeast IL for wind chills of 15-25 below zero.
A northern stream short wave that digs into the trof over IL/IN
tonight keeps most of its light snow just south of central IL CWA
though scattered flurries will likely occur tonight into Wed. 850 mb
temps drop to -25 to -27C by Wed evening and this to be another
frigid air mass with highs struggling to reach 10F both Wed and Thu.
Lows Tue night in the single digits, then drop into single digits
below zero Wed night and some areas near IN border could dip below
zero again Thu night. A secondary arctic cold front plows se through
central IL late tonight into Wed morning. Brisk nw winds behind this
cold front on Wed will already bring wind chills down to -15F or a
bit colder Wed morning over IL river valley especially nw of the
river and reaching near wind chill advisory criteria. Coldest wind
chills of 15-25 below zero will occur Wed night into Thu morning and
coldest readings over Knox and Stark counties.
Deep upper level trof shifts east of IL Thu night and Friday while
arctic high pressure also drifts east of IL across the Ohio river
valley Thu night and Fri morning. Temps will be slow to climb
however on Friday due to mostly cloudy skies with highs in the low to
mid 20s. Have small chances of light snow Friday afternoon sw
counties ahead of next short wave. Extended models still differ with
handling southern stream storm system this weekend. ECWMF model has
trended further south with it surface low from central IL down to
just south of IL Sat. While GFS has surface low near KY/TN border by
midnight Sat night. GEM model moves low across TN on Sat. Due to
difference in models and from previous runs, stayed close to
guidance pops which are trending upward in southeast IL Sat/Sat
night. Looks cold enough for mainly light snow, though do continue a
mix over southeast IL on Sat. Have just slight chance of light snow
Sunday and then dry across area by Sunday evening. Highs in the low
to mid 30s Sat cool off again early next week on Sunday and Monday
behind this storm system.
The Climate Prediction Center (CPC) day 8-14 outlook for Feb 24-Mar
2 has IL in greater than 60% chance of below normal temperatures and
greater than 40% chance of below normal precipitaton. So winter
looks to hold on the next two weeks.
&&
.AVIATION...(For the 06Z TAFS through 06Z Tuesday night)
ISSUED AT 1110 PM CST MON FEB 16 2015
Low VFR cigs spreading slowly east and southeast late this
evening and should encompass all TAF sites by 09z. Cold front
pushing across east central Iowa will bring about a wind shift
Tuesday morning into the west and northwest along with a period
of MVFR cigs immediately behind the frontal passage. Latest RAP
and HRRR forecasts suggest the MVFR cigs should push into PIA
around 09z and finally into CMI at 12z. Based on the past several
forecast runs, it appears about a 2-3 hour period of MVFR cigs
before improving to VFR by 15z at PIA and 18z over in CMI.
500 mb trof axis still located to our west on Tuesday so if we do
see any breaks in the cloud cover, the rather cold 500 mb temps
will lead to some scattered to broken stratocu clouds between
3000-4000 feet during the afternoon. At this point will include a
scattered group at 3500 feet. A few flurries will be possible with
or just behind the cold front tomorrow morning and possibly again
the afternoon but at this time it appears coverage will be quite
limited so have decided to hold off any mention of flurries in
this set of TAFs. Surface winds will be light southwest overnight
and switch into the west around dawn Tuesday and then into the
northwest as the front shifts off to our east. Wind speeds tonight
will be less than 10 kts and increase to between 10 and 15 kts
on Tuesday with a few gusts near 20 kts by late morning or early
afternoon, before diminishing around sunset.
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...Shimon
LONG TERM...07
AVIATION...Smith
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
1133 PM CST MON FEB 16 2015
.SHORT TERM...
224 PM CST
THROUGH WEDNESDAY...
RELATIVELY QUIET DAY TODAY...WITH THE SNOW PASSING WELL SOUTH OF THE
FORECAST AREA AND LIGHT/VARIABLE WINDS THIS AFTN. THIS HAS KEPT THE
LAKE EFFECT SNOW CONFINED TO THE CENTRAL/NORTHERN PORTIONS OF THE
LAKE...WHICH REMAINS VISIBLE ON SATELLITE IMAGERY. SFC TEMPS HAVE
REMAINED IN THE TEENS ACROSS MUCH OF THE FORECAST AREA. THE EXTREME
SOUTHERN CWFA MAY BE ABLE TO SEE A FEW LOCATIONS TOUCH 20 DEGREES
LATE THIS AFTN.
WEAK GRADIENT WILL REMAIN OVER THE FORECAST AREA TONIGHT...THEN AS
DAYBREAK APPROACHES THE ARCTIC AIR ACROSS THE UPPER MIDWEST WILL
DIVE SOUTH. POTENT 850MB THERMAL TROUGH OF -18 TO -20 DEG C ARRIVES
ACROSS THE NORTHERN CWFA BY 15Z TUE...THEN CONTINUES TO PUSH
SOUTH/SOUTHEAST THROUGHOUT THE AFTN. TEMPS SHUD BE ABLE TO WARM INTO
THE MID/UPR TEENS BY MIDDAY...THEN REMAIN STATIONARY WITH THE COLD
AIR ADVECTING IN. THE FAR NORTHWEST CWFA MAY OBSERVE FALLING TEMPS
BY EARLY AFTN. GUIDANCE HAS CONTINUED TO HINT THAT SOME LGT SNOW MAY
DEVELOP IN THE AFTN HOURS. THE MOISTURE IS VERY
SHALLOW/MARGINAL...BUT WITH LAPSE RATES STEEPENING IT IS POSSIBLE WE
COULD SEE SOME LGT SNOW BUT OPTED TO MENTION FLURRIES AT THIS TIME.
THEN AFT SUNSET TUE EVE THE MOISTURE DEPTH DECREASES WITH LIFT
BECOMING MINIMAL. SO THERE COULD BE A LULL IN FLURRIES/LGT
SNOW...UNTIL A REINFORCING TROUGH OF COLD AIR ARRIVES TUE NGT/EARLY
WED. MOISTURE CONTINUES TO BE MINIMAL TUE NGT/EARLY WED...BUT THE
LIFT/OMEGA ALONG WITH LAPSE RATES LOOKS SLIGHTLY BETTER. SO HAVE
HELD ONTO A SLT CHC POPS OR LGT SNOW IN THIS TIMEFRAME. ANY
ACCUMULATIONS SHOULD BE LESS THAN ONE INCH. WINDS WILL BE ON THE
INCREASE TUE NGT/EARLY WED...WITH LOWS AROUND 0 AND WIND CHILLS
DIPPING INTO THE TEENS BELOW ZERO.
THE THERMAL TROUGH TUE NGT/WED WILL BE MUCH COLDER THAN THE PRIOR
NIGHT...WITH GUIDANCE PROGGING -22 TO -24 DEG C BY WED. THIS WILL
LIKELY KEEP TEMPS FROM WARMING MUCH BEYOND THE SINGLE DIGITS ABOVE
ZERO. CLOUD COVER WILL BE DECREASING WED NGT WITH HIGH PRESSURE
BUILDING IN FROM THE WEST. WINDS WILL REMAIN BREEZY FROM THE
NORTHWEST. WITH CLOUDS THINNING WED NGT...TEMPS WILL QUICKLY
RADIATING INTO THE SINGLE DIGITS BELOW ZERO. DANGEROUS WIND CHILLS
ARE FORECAST FOR EARLY THUR...APPROACHING -20 TO -30 DEG.
BEACHLER
&&
.LONG TERM...
224 PM CST
THURSDAY THROUGH MONDAY...
THE LONGWAVE PATTERN GOING THROUGH THE END OF THE WEEK INTO EARLY
NEXT WEEK LOOKS TO BE A REPEAT OF THE PAST. HIGH AMPLITUDE RIDGE
ACROSS ALASKA COUPLED WITH A DOWNSTREAM RIDGE OVER THE NORTH
ATLANTIC WILL LOCK IN PLACE THE BROAD TROUGHING ACROSS THE CENTRAL
CONUS/GREAT LAKES/NORTHEAST CONUS THROUGH AT LEAST THE NEXT WEEK.
THERE IS SOME RELAXING TO THE POTENCY OF THE THERMAL TROUGH OVER THE
WEEKEND...HOWEVER ENSEMBLES ARE IN GOOD AGREEMENT THAT THE RIDGE
OVER ALASKA MAY FURTHER STRENGTHEN HEADING INTO THE SECOND HALF OF
THE WEEKEND/EARLY NEXT WEEK.
PERIODIC CHANCES FOR FLURRIES/LGT SNOW WILL ARRIVE OVER THE
WEEKEND/EARLY NEXT WEEK. TEMPS THUR WILL REMAIN IN THE SINGLE DIGITS
ABOVE ZERO...TO THE TEENS FRI. THEN OVER THE WEEKEND WITH SOME
RELAXING TO THE ARCTIC AIRMASS...TEMPS SHUD RETURN TO THE MID/UPR
20S.
BEACHLER
&&
.CLIMATE...
WHILE THE COLDEST AIR ALOFT ARRIVES WEDNESDAY...THE COLDEST SURFACE
TEMPERATURES MAY RESULT ON THURSDAY FEBRUARY 19TH...WHICH RIGHT NOW
APPEARS COULD JEOPARDIZE SOME RECORDS...ESPECIALLY THE LOW MAXS.
FEB 19TH
RECORD LOW RECORD LOW MAX
CHICAGO -7 (1936) 9 (1936)
ROCKFORD -16 (1979) 7 (1959)
MTF
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 06Z...
* POTENTIAL FOR SOME SNOW SHOWERS AND FLURRIES TOWARDS
MORNING...MVFR CONDITIONS POSSIBLE.
* POTENTIAL FOR A SHORT PERIOD OF HEAVIER SNOW SHOWERS LATE
TUESDAY NIGHT WITH IFR POSSIBLE.
KJB
//DISCUSSION...UPDATED 06Z...
A COLD FRONT WILL MOVE ACROSS THE TERMINALS AROUND DAYBREAK THIS
MORNING. A FEW LIGHT SNOW SHOWERS AND FLURRIES WILL LIKELY PUSH
ACROSS THE AREA PRIOR TO ITS ARRIVAL...AND THIS COULD RESULT IN SOME
BRIEF PERIODS OF SOME MVFR VIS AND CIGS. OTHERWISE MOST OF THE DAY
TODAY WILL BE DOMINATED BY A WEST-NORTHWEST WIND AROUND 290 DEGREES
WITH SOME SOME LOW END GUSTS UP AROUND 18 KT POSSIBLE.
LATER IN THE TAF PERIOD...LATER TUESDAY NIGHT...A STRONG ATMOSPHERIC
DISTURBANCE IS EXPECTED TO MOVE OVER THE AREA. AS THIS DOES SO...A
PERIOD OF HEAVIER SNOW SHOWERS COULD OCCUR...AND THIS COULD RESULT
IN REDUCED VISIBILITIES AND SOME MINOR SNOW ACCUMULATIONS. AT THIS
TIME IT APPEARS THE BEST POTENTIAL WOULD COME AFTER 06 UTC WEDNESDAY
MORNING. IT ALSO APPEARS TO BE A SHORT LIVED EVENT. I HAVE ADDED A
PROB 30 TO THE CURRENT 30 HOUR ORD TAF TO ADVERTISE THIS POTENTIAL.
KJB
//ORD AND MDW CONFIDENCE...UPDATED 06Z...
* MEDIUM ON TIMING OF SNOW SHOWERS THIS MORNING.
* LOW TO MEDIUM ON EXTENT OF SNOW SHOWERS LATER TUESDAY NIGHT.
KJB
//OUTLOOK FOR ORD/MDW FOR 12Z WEDNESDAY-12Z MONDAY...UPDATED 00Z...
WEDNESDAY...CHANCE OF FLURRIES ESPECIALLY EARLY. MVFR CIGS
POSSIBLE. BREEZY NORTHWEST WINDS.
THURSDAY...MAINLY VFR. NORTHWEST WINDS.
FRIDAY...CHANCE OF SNOW MAINLY FRIDAY NIGHT. MVFR/IFR POSSIBLE
LATE. SOUTH WINDS.
SATURDAY...CHANCE OF SNOW. MVFR POSSIBLE. SOUTHWEST WINDS
BECOMING NORTHWEST.
SUNDAY...SLIGHT CHANCE OF SNOW SHOWERS. MVFR POSSIBLE. NORTH-
NORTHEAST WINDS.
RATZER
&&
.MARINE...
216 PM...HIGH PRESSURE OVER THE EASTERN LAKES WILL MOVE NORTHEAST
TONIGHT AS IT WEAKENS. A COLD FRONT/TROUGH OF LOW PRESSURE OVER
THE UPPER MIDWEST WILL MOVE SOUTHEAST ACROSS THE LAKE OVERNIGHT.
WEAK LOW PRESSURE WILL DEVELOP ALONG THIS TROUGH OVER EASTERN LAKE
SUPERIOR TUESDAY MORNING. AS THIS LOW MOVES TO LAKE HURON TUESDAY
NIGHT...THE GRADIENT WILL REMAIN WEAK OVER NORTHERN LAKE MICHIGAN.
THE GRADIENT WILL SLOWLY TIGHTEN OVER SOUTHERN LAKE MICHIGAN INTO
WEDNESDAY MORNING AS HIGH PRESSURE BUILDS ACROSS THE PLAINS. THIS
HIGH WILL MOVE SOUTHEAST TO THE OHIO VALLEY BY THURSDAY EVENING...
AS THE GRADIENT SLOWLY WEAKENS OVER THE WESTERN LAKES. THERE COULD
BE A PERIOD OF LOW END GALES OVER THE SOUTHERN HALF OR SO OF LAKE
MICHIGAN ON WEDNESDAY...BUT CONFIDENCE IS LOW. AS THE HIGH SHIFTS
EAST OF THE LAKE...WINDS WILL TURN SOUTHERLY FRIDAY AND FRIDAY
NIGHT. CMS
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...NONE.
&&
$$
VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)
FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
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Area Forecast Discussion
NATIONAL WEATHER SERVICE LINCOLN IL
1115 PM CST Mon Feb 16 2015
.UPDATE...
ISSUED AT 825 PM CST MON FEB 16 2015
The storm system that produced the heavy snow over southeast
Illinois last night through this morning has shifted well east
of our area early this evening with weak high pressure moving
across central Illinois. The latest surface map showing another
cold front poised to our northwest and forecast to track across
our area tomorrow morning. Other than some lower clouds and
scattered flurries, not much in the way of weather associated
with it. As far as tonight is concerned, clouds were on the
increase again over northwest Illinois, but were still mostly
clear over east central and far southeast Illinois. The
combination of the mostly clear sky and relatively light winds
in southeast Illinois, coupled with a fresh snow cover, has
led to some rapid temperature falls. Have made some adjustments
to the early evening as well as overnight temperatures in this
area to account for the faster temperature decline this evening.
Should have an updated forecast out by 845 pm.
&&
.SHORT TERM...(Tonight)
ISSUED AT 306 PM CST MON FEB 16 2015
20z/2pm analysis shows light snow continuing to fall across the E/SE
KILX CWA, mainly along/southeast of an Effingham to Paris line.
Based on radar timing tools, most of the precip will shift into
Indiana by 00z: however, will hang on to slight chance PoPs across
the far SE around Robinson and Lawrenceville through early evening
in case departure slows. Further north and west, the cloud cover
has thinned out this afternoon, allowing a few peeks of sunshine to
occur. Partly to mostly cloudy conditions will prevail through the
evening hours before a cold front currently across Minnesota/the
Dakotas approaches from the northwest overnight. Clouds will be on
the increase ahead of the boundary and a few snow flurries may occur
along/west of I-55 as the profile moistens and lift increases.
Overnight low temperatures will be coldest across the southeast
where a deep snow cover is in place. Have therefore undercut MAV
guidance numbers by a couple of degrees there, resulting in lows in
the single digits along/south of a Taylorville to Paris line.
Elsewhere have gone a little above guidance in the teens due to
increasing clouds and a light SW flow ahead of the approaching cold
front.
&&
.LONG TERM...(Tuesday through Monday)
ISSUED AT 306 PM CST MON FEB 16 2015
A very cold midweek forecast is shaping up. A surface cold front
will push southeastward across central Illinois through the day
Tuesday causing temperatures to level off early in the day and
eventually decrease in the late afternoon. Highs will range from the
mid teens to lower 20s. Areas northwest of the Illinois River may
see max temperatures before noon, while areas south of I-70 may see
max temperatures mid afternoon. Limited moisture will cause this to
have little precipitation associated with it, however scattered snow
flurries will be possible as the surface cold front and upper trough
cross the area. Brisk northwest winds of 10-15 mph will follow the
cold front causing very chilly conditions.
Another cold front will trail closely behind for early Wednesday
morning bringing in even colder temperatures and winds 15-20 mph
with gusts to the mid 20s. Low temperatures of around 0 to 5 degrees
above are expected Wednesday morning. This will result in wind chill
temperatures of -15 to -20 degrees as far south as I-72. This may
require the issuance of a wind chill advisory for these areas. A few
more snow flurries are possible along with the cold front. Sub-zero
temperatures will continue to spread southeastward across the region
by Thursday morning resulting in wind chill temperatures of -15 to
-25 degrees throughout central IL.
Temperatures will gradually moderate late in the week as the deep
trough over the central and eastern U.S. shifts eastward allowing a
southerly flow to develop along with some light warm frontal
precipitation by Friday into the weekend. Models still disagreeing on
whether a significant precipitation event could take shape over the
weekend. ECMWF model has been closest to this idea with a low
tracking northeastward across the southern tip of Illinois while GFS
and Canadian keep significant precipitation off to the south. ECMWF
has trended slightly southward in the 12Z solution versus last
nights 00Z solution.
&&
.AVIATION...(For the 06Z TAFS through 06Z Tuesday night)
ISSUED AT 1110 PM CST MON FEB 16 2015
Low VFR cigs spreading slowly east and southeast late this
evening and should encompass all TAF sites by 09z. Cold front
pushing across east central Iowa will bring about a wind shift
Tuesday morning into the west and northwest along with a period
of MVFR cigs immediately behind the frontal passage. Latest RAP
and HRRR forecasts suggest the MVFR cigs should push into PIA
around 09z and finally into CMI at 12z. Based on the past several
forecast runs, it appears about a 2-3 hour period of MVFR cigs
before improving to VFR by 15z at PIA and 18z over in CMI.
500 mb trof axis still located to our west on Tuesday so if we do
see any breaks in the cloud cover, the rather cold 500 mb temps
will lead to some scattered to broken stratocu clouds between
3000-4000 feet during the afternoon. At this point will include a
scattered group at 3500 feet. A few flurries will be possible with
or just behind the cold front tomorrow morning and possibly again
the afternoon but at this time it appears coverage will be quite
limited so have decided to hold off any mention of flurries in
this set of TAFs. Surface winds will be light southwest overnight
and switch into the west around dawn Tuesday and then into the
northwest as the front shifts off to our east. Wind speeds tonight
will be less than 10 kts and increase to between 10 and 15 kts
on Tuesday with a few gusts near 20 kts by late morning or early
afternoon, before diminishing around sunset.
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...Smith
SHORT TERM...Barnes
LONG TERM...Onton
AVIATION...Smith
AREA FORECAST DISCUSSION
NWS NORTHERN INDIANA
643 PM EST WED FEB 18 2015
.SYNOPSIS...
ISSUED AT 640 PM EST WED FEB 18 2015
PERIODS OF MODERATE TO HEAVY LAKE EFFECT SNOW WILL CONTINUE
TONIGHT AND THURSDAY. THE HEAVIEST WILL BE ACROSS FAR NORTHERN
INDIANA AND SOUTHWEST LOWER MICHIGAN WHERE UP TO A FOOT OF SNOW
MAY FALL. LOW TEMPERATURES TONIGHT WILL RANGE FROM A FEW DEGREES
ABOVE ZERO NEAR LAKE MICHIGAN TO AS LOW AS TEN BELOW ZERO AWAY
FROM THE LAKE. DANGEROUS WIND CHILLS ARE ALSO EXPECTED TONIGHT
THROUGH FRIDAY MORNING...GENERALLY RANGING BETWEEN 10 BELOW AND 25
BELOW ZERO. HIGH TEMPERATURES ON THURSDAY WILL ONLY BE BETWEEN
ZERO AND 5 ABOVE.
&&
.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 00Z TAFS THROUGH 00Z THURSDAY EVENING)
ISSUED AT 635 PM EST WED FEB 18 2015
NORTHWEST FLOW THIS EVENING WILL KEEP SCATTERED LAKE EFFECT SNOW
SHOWERS GOING AT KSBN. VIS HAS BEEN AROUND 1/2SM THIS EVENING BUT
VIS SENSOR OCCASIONALLY BOUNCING DOWN TO 1/4SM BRIEFLY. WITH SOME
HIGHER RETURNS NOTED NW OF TERMINAL OPTED TO HOLD ONTO THE LIFR
CONDITIONS FOR A FEW MORE HOURS. STILL EXPECT MVFR AND IFR
CONDITIONS AT TIMES OVERNIGHT WITH PERSISTENT SNOW SHOWERS. NEXT
STRONG BAND DROPS SOUTH TOWARD DAYBREAK AND SHOULD SEE
DEVELOPMENT TAKE OFF AGAIN AROUND 12Z FOR SEVERAL HOURS. THIS WILL
AGAIN BE FOLLOWED BY WEAKENING BUT PERSISTENT SNOW SHOWERS LATE
MORNING AND AFTERNOON WITH IFR AND POSSIBLE LIFR CONTINUING DEPENDING
ON BAND LOCATION.
&&
.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.
WINTER WEATHER ADVISORY UNTIL 10 PM EST THIS EVENING FOR
INZ007>009-016.
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...LASHLEY
SHORT TERM...T
LONG TERM...FISHER
AVIATION...LASHLEY
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AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
1133 PM EST MON FEB 16 2015
.UPDATE...
THE AVIATION SECTION HAS BEEN UPDATED BELOW.
&&
.SYNOPSIS...
ISSUED AT 953 PM EST MON FEB 16 2015
A HIGH PRESSURE RIDGE WILL BRIEFLY BUILD IN OVERNIGHT WITH MAINLY
CLEAR SKIES AND COLD TEMPERATURES. THE UPPER TROUGH OVER THE AREA
WILL GET REINFORCED TUESDAY NIGHT WITH ANOTHER SHOT OF COLD AIR
THAT WILL BRING DANGEROUS COLD TO THE AREA TUESDAY NIGHT THROUGH
THURSDAY NIGHT. THE WEEKEND SHOULD BRING A WARMUP TO THE AREA BUT
WILL ALSO BRING ADDITIONAL CHANCES FOR ACCUMULATING SNOW.
&&
.NEAR TERM /OVERNIGHT/...
ISSUED AT 953 PM EST MON FEB 16 2015
SNOW HAS DEPARTED OUT OF THE FORECAST AREA WITH FAIRLY RAPID
CLEARING AS A HIGH PRESSURE RIDGE BUILDS ACROSS THE AREA. TEMPS
VARIED WIDELY AT 0230Z...RANGING FROM NEAR 0 DEGREES IN SOME
LOCATIONS WITH A SNOWPACK TO THE TEENS IN OTHER SPOTS.
AFTER THE SNOWFALL TODAY...RELATIVELY QUIET FORECAST SETS UP
OVERNIGHT WITH THE ONLY REAL ISSUE FOCUSED ON THE LOW TEMPS. HIGH
PRESSURE RIDGE WILL DRIFT EAST ACROSS THE OHIO VALLEY TONIGHT WITH
STRATUS BACK OVER THE MISSISSIPPI VALLEY HOLDING OFF UNTIL LATE
TONIGHT IN THE WEST AND LIKELY CLOSER TO DAYBREAK OVER EASTERN
COUNTIES. WITH MAINLY CLEAR SKIES EXPECTED FOR SEVERAL HOURS AND
LIGHT WINDS...TEMPERATURES WILL TUMBLE. COLDEST TEMPS WILL LIKELY
BE FOUND IN SOUTHERN COUNTIES WITH THE PRESENCE OF A FRESH AND IN
SOME SPOTS DEEP SNOWPACK. UTILIZED 00Z RAP FOR HOURLY TEMPS BUT IN
GENERAL...DROPPED LOWS IN SOME SPOTS SEVERAL DEGREES. DO EXPECT
NORMAL COOL SPOTS OVER SOUTHERN FORECAST AREA WILL GO SUBZERO...
MAYBE AS LOW AS -5.
ZONE AND GRID UPDATES OUT.
&&
.SHORT TERM /TUESDAY THROUGH THURSDAY/...
ISSUED AT 348 PM EST MON FEB 16 2015
THE MAIN FOCUS IN THE SHORT TERM IS THE COLD TEMPERATURES AND WIND
CHILLS. MODELS ARE IN DECENT AGREEMENT ON PATTERN BUT MOS GUIDANCE
NUMBERS SHOWING SOME DIFFERENCES AND WILL DISCUSS PREFERENCE AND
REASONING BELOW.
A LARGE UPPER TROUGH WILL CONTINUE TO HOLD SWAY OVER THE EASTERN U.S
THROUGH THE SHORT TERM. THIS WILL ALLOW FOR A STEADY STREAM OF COLD
AIR INTO CENTRAL INDIANA. GIVEN MODEL 850 MB TEMPERATURES STARTING
IN THE -TEENS AND DROPPING INTO THE -22 TO -28 RANGE HAVE FAVORED
THE COLDER GUIDANCE NUMBERS OF THE MAV...AND HAVE EVEN DROPPED SOME
FROM THERE AT TIMES. LOWS TUESDAY NIGHT/WEDNESDAY MORNING WILL BE IN
THE LOW SINGLE DIGITS TO BELOW ZERO OVER THE SOUTHERN AREAS WITH
SNOWPACK FROM TODAY. WEDNESDAY NIGHT COULD SEE LOWS FROM A FEW
DEGREES BELOW ZERO TO NEAR 10 BELOW ZERO OVER THE SNOWPACK. HIGHS ON
WEDNESDAY AND THURSDAY WILL BE MAINLY IN THE SINGLE DIGITS.
WITH CYCLONIC FLOW LOOK FOR MOSTLY CLOUDY SKIES TO BE THE RULE ALONG
WITH SOME SLIGHT CHANCES FOR LIGHT SNOW AND BETTER CHANCES FOR
FLURRIES OFF AND ON. THERE IS SOME DISCERNIBLE UPPER FORCING TUESDAY
EVENING AND AGAIN ON WEDNESDAY BUT WITH LITTLE MOISTURE TO WORK WITH
WILL JUST CARRY SLIGHT CHANCES.
WILL LIKELY NEED HEADLINES FOR WIND CHILLS WEDNESDAY AND
THURSDAY...BUT GIVEN THE NUMBER OF PERIODS OUT AND CURRENT
HEADLINES RUNNING WOULD PREFER TO WAIT PAST THIS ISSUANCE.
&&
.LONG TERM /THURSDAY NIGHT THROUGH MONDAY/...
ISSUED AT 245 PM EST MON FEB 16 2015
TEMPERATURES AND POPS INCLUDING TIMING AND PRECIP TYPE WILL BE THE
MAIN CONCERN FOR THE EXTENDED. AT THIS TIME...EXTENDED MODELS AND
ENSEMBLES ARE TOO FAR APART TO CONFIDENTLY CHANGE THE REGIONAL
BLEND...SO LEFT IT AS IT IS WITH CHANCE POPS STARTING FRIDAY NIGHT
AS A WARM FRONT LIFTS UP FROM THE SOUTHWEST. POPS IN ORDER THROUGH
LATE WEEKEND WITH SOUTHERLY FLOW AHEAD OF A FRONTAL SYSTEM. COULD
SEE A WINTRY MIX ACROSS OUR FAR SOUTHERN ZONES..BUT AT THIS POINT
WILL LEAVE IT ALL SNOW AND ADJUST AS IT GETS CLOSER AND OR MODELS
CONVERGE UPON A COMMON SOLUTION.
TEMPERATURES SHOULD START OFF COLD WITHIN DEPARTING ARCTIC HIGH
PRESSURE BUT THEN WARM TO CLOSER TO NORMAL BY SATURDAY AS THE WARM
FRONT MOVES THROUGH. STILL...EVEN THEN AND MORE SO AFTER THE COLD
FRONTAL PASSAGE...BELOW NORMAL TEMPERATURES WILL CONTINUE.
&&
.AVIATION /DISCUSSION FOR THE 170600Z TAFS/...
ISSUED AT 1133 PM EST MON FEB 16 2015
SYNOPTIC PATTERN FAVORS FOG DEVELOPMENT OVERNIGHT OVER FRESH SNOW
COVER IN THE KBMG AND POSSIBLY THE KHUF AREAS. WILL ADD SOME
VISIBILITY RESTRICTIONS IN FOG IN THE KBMG AREA THROUGH THE MID
MORNING HOURS OF TUESDAY. AT THIS TIME...APPEARS ANY IFR
RESTRICTIONS WILL BE FAIRLY BRIEF AND LOCALIZED...SO WILL KEEP
CONDITIONS ABOVE IFR. CONFIDENCE IN VISIBILITY RESTRICTIONS AT KHUF
IS LOWER...SO WILL LEAVE OUT THERE.
OTHERWISE...VFR DECK 040-050 PUSHING SOUTHEAST THROUGH NORTHERN
ILLINOIS EXPECTED TO BEGIN MOVING INTO THE TAF SITES FROM THE
NORTHWEST AFTER 170900Z. MVFR CEILINGS AROUND 025 SHOULD BEGIN TO
DEVELOP TOWARDS MIDDAY TUESDAY AS LOWER LEVEL LAPSE RATE STEEPEN. A
FEW LIGHT SNOW SHOWERS MAY DEVELOP TOWARDS MIDDAY AS WELL...BUT
POTENTIAL FOR VISIBILITY RESTRICTIONS LOOK LOW AT THIS TIME.
MORE WIDESPREAD SNOW SHOWER ACTIVITY POSSIBLE AFTER 171800Z AS A
FRONT MOVES THROUGH.
LIGHT SURFACE WINDS OVERNIGHT EXPECTED TO BECOME 240-270 DEGREES AT
8-11 KTS BY MIDDAY TUESDAY.
&&
.IND WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
SYNOPSIS...CP/RYAN
NEAR TERM...RYAN
SHORT TERM...CP
LONG TERM...MK
AVIATION...JAS
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AREA FORECAST DISCUSSION...UPDATED
NWS QUAD CITIES IA IL
948 AM CST TUE FEB 17 2015
.UPDATE...
ISSUED AT 942 AM CST TUE FEB 17 2015
9AM TEMPERATURES ACROSS THE AREA WERE HIGHER THAN FORECAST FOR 10
AM. A QUICK LOOK AT THE RUC AND HRRR HIGH TEMPS AND THE SATELLITE
IMAGE...SUPPORTS DAYTIME HIGH TEMPS BEING SLIGHTLY HIGHER THAN
PREVIOUS FORECAST...ESPECIALLY ACROSS SOUTHERN PORTIONS OF THE
CWA. RAISED POPS A FEW DEGREES CWA WIDE. ALSO ADDED SN-- TO MORE
OF THE NW ZONES TODAY. AGITATED CU FIELD WAS LEADING TO FLURRIES
AS THEY HEADED SOUTH IN THE N TO NW FLOW. NO ACCUMULATION IS
EXPECTED DURING THE DAY FROM THESE FLURRIES.
&&
.SYNOPSIS...
ISSUED AT 342 AM CST TUE FEB 17 2015
MSAS SURFACE ANALYSIS INDICATED THE SURFACE COLD FRONT EXTENDED
FROM EASTERN UPPER MI SW ACROSS WI...EASTERN IA TO N CENTRAL KS AT
08Z. IN THE LOCAL AREA...THE BOUNDARY WAS ROUGHLY FROM KMSN
THROUGH THE QUAD CITIES TO JUST NORTH OF KIRK. A POST FRONTAL
SURGE OF MID LEVEL SUBSIDENCE AND DRY AIR HAD LEAD TO A LARGE AREA
OF CLEARING IN THE STRATOCU ACROSS MUCH OF CENTRAL IA...WITH
SATELLITE IR/FOG CHANNEL IMAGERY SHOWING PATCHY LOW CLOUDS UPSTREAM
UNDER THE NW FLOW ALOFT ACROSS MN AND THE DAKOTAS. KDVN 88D AND
SURFACE REPORTS INDICATED SCATTERED FLURRIES OR VERY LIGHT SNOW
SHOWERS PUSHING EAST AHEAD OF THE FRONT ACROSS NW IL. WITH A
RATHER UNIMPRESSIVE POST FRONTAL PRESSURE RISES...WINDS WERE ONLY
INCREASING TO 10 TO 15 KTS IMMEDIATELY BEHIND THE FRONT.
LIKEWISE...THE COLD AIR ADVECTION WAS ONLY LOWERING TEMPERATURES
INTO THE UPPER SINGLE DIGITS OVER NE IA...WHILE READINGS WERE
STEADY TO SLOWLY FALLING IN THE TEENS TO LOWER 20S OVER THE LOCAL
AREA. THE MORE IMPRESSIVE PUSH OF ARCTIC AIR WAS FURTHER NORTH
BEHIND A SUBTLE SECONDARY COLD FRONT ACROSS WI...MN INTO
SD...MARKING THE LEADING EDGE OF TEMPERATURES IN THE SINGLE DIGITS
BELOW ZERO TO THE NORTH.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 342 AM CST TUE FEB 17 2015
THE ONSET OF COLDER TEMPERATURES AND ASSOCIATED BITTER COLD WIND
CHILLS IS THE PRIMARY FOCUS. HAVE ISSUED A WIND CHILL ADVISORY
FOR LATE TONIGHT THROUGH WED MORNING OVER EASTERN IA...WHERE WIND
CHILLS WILL LIKELY DROP BELOW -20 FOR A SUFFICIENT PERIOD DUE TO
INCREASING NW WINDS AND FALLING TEMPERATURES BEHIND THE SECONDARY
FRONTAL SURGE LATE TONIGHT.
TODAY...TEMPERATURES HAVE BEEN ADJUSTED UPWARDS IN THE NEAR TERM
FOLLOWING A SLIGHTLY SLOWER FRONTAL PASSAGE AND WEAKER COLD AIR
ADVECTION THAT FOLLOWS. THROUGH THE REST OF THE DAY...THERE IS A
GOOD POTENTIAL FOR PERIODS OF SUNSHINE LOOKING AT THE LIMITED EXTENT
OF LOW CLOUDS UPSTREAM AND MEAGER MOISTURE ON AREA SOUNDINGS. STEEP
LOW LEVEL LAPSE RATES AND A SHALLOW LOW LEVEL MOISTURE LAYER MOVING
OUT OF THE PLAINS WILL SUPPORT FLURRIES OVER ESPECIALLY THE SOUTH.
AFTER FALLING THROUGH AT LEAST MID MORNING...TEMPERATURES SHOULD
RECOVER TO HIGHS FROM AROUND 10 NORTH TO 20 IN THE FAR SOUTH.
TONIGHT...AN ADVANCING...STRENGTHENING UPPER LEVEL SHORTWAVE
TROUGH AND REINFORCING SHOT OF COLD AIR ADVECTION WILL LIKELY
SPREAD SCATTERED SNOW SHOWERS OR FLURRIES OVER THE FORECAST AREA.
WILL HAVE HIGHER CHANCE POPS FOR POSSIBLE DUSTING OF ACCUMULATION
ACROSS THE NORTH AND NORTHEAST. DEVELOPING NW WINDS FROM 15 TO 25
MPH AND TEMPERATURES FALLING TO AROUND ZERO IN THE NORTH TOWARD
DAWN WILL LIKELY DRIVE WIND CHILLS INTO THE ADVISORY THRESHOLD
RANGE OF -20 AND BELOW BEGINNING AFTER ABOUT 3 AM...MAINLY OVER
EAST CENTRAL IA. CURRENT FORECAST PARAMETERS HAVE WIND CHILLS
MAINLY IN THE MINUS TEENS ELSEWHERE. MIN TEMPERATURES FORECAST IN
A RANGE OF 3 BELOW TO 3 ABOVE WILL LIKELY OCCUR AFTER SUNRISE.
BASED ON BIASES FROM RECENT EVENTS AND THE LATE SEASON TIMING...HAVE
TRENDED TEMPERATURES ON THE WARMER SIDE OF FORECAST GUIDANCE.
.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 342 AM CST TUE FEB 17 2015
THE CONSISTENT MESSAGE IS A CONTINUATION OF WELL BELOW NORMAL
TEMPERATURES FOR THE AREA.
THE PROXIMITY OF THE UPPER LEVEL DISTURBANCE AT SUNRISE WEDNESDAY
SUGGESTS THAT SOME FLURRIES MAY PERSIST INTO THE FIRST PART OF THE
MORNING ACROSS THE FAR EAST AND NORTHEAST AREAS. ONCE THE
DISTURBANCE MOVES INTO THE GREAT LAKES SKIES SHOULD SLOWLY CLEAR
DURING THE DAY.
THE STRONGER SUN ANGLE SHOULD PARTIALLY HELP TO OFFSET THE COLD AIR
ADVECTING INTO THE AREA ON WEDNESDAY. REGARDLESS...IT WILL BE VERY
COLD WITH MAX TEMPERATURES 25 TO 30 DEGREES BELOW NORMAL.
THE ARCTIC HIGH SETTLES ACROSS THE AREA WEDNESDAY NIGHT RESULTING IN
BITTER COLD. BASED ON FORECAST LOWS AND WIND SPEEDS...HEADLINES FOR
WIND CHILL WILL BE NEEDED FOR MUCH OF THE AREA WEDNESDAY NIGHT THAT
EXTENDS INTO THURSDAY MORNING. CONFIDENCE ON THIS IS NOW MODERATE TO
HIGH.
QUIET AND COLD CONDITIONS WILL BE SEEN ACROSS THE AREA ON THURSDAY
AS THE ARCTIC HIGH MOVES ACROSS THE AREA. MAX TEMPERATURES WILL
CONTINUE TO BE 25 TO 30 DEGREES BELOW NORMAL.
QUIET AND DRY CONDITIONS WILL BE SEEN ACROSS THE AREA THURSDAY
EVENING. THERE SHOULD BE A QUICK DROP OFF IN TEMPERATURES BEFORE
CLOUDS ASSOCIATED WITH AN UPPER LEVEL DISTURBANCE MOVE INTO THE AREA.
LATE THURSDAY NIGHT A BAND OF LIGHT SNOW WILL MOVE ACROSS WESTERN
IOWA. MOST OF THE AREA WILL REMAIN DRY LATE THURSDAY NIGHT BUT THE
FAR SOUTHWEST AND SOUTH AREAS MAY SEE SOME FLURRIES OR LIGHT SNOW.
THE KEY TO WHETHER ANY PRECIPITATION OCCURS WILL BE THE DEPTH OF THE
DRY AIR ACROSS THE AREA.
FRIDAY ON...
THE MODELS CONTINUE THE TREND OF BELOW NORMAL TEMPERATURES THROUGH
NEXT WEEKEND AND INTO EARLY NEXT WEEK.
THE SOUTHERN JET WILL REMAIN ACTIVE FROM THE SOUTHERN PLAINS INTO
THE TENNESSEE VALLEY BUT SEVERAL WEAK DISTURBANCES WILL BE MOVING
SOUTHEAST ACROSS THE AREA IN THE NORTHERN JET. AS SUCH THERE WILL BE
SEVERAL CHANCES FOR FLURRIES OR VERY LIGHT SNOW FRIDAY THROUGH THE
FIRST PART OF THE WEEKEND. HOWEVER...LIMITED MOISTURE SUGGESTS ANY
SNOWFALL WOULD BE A TRACE TO A DUSTING MOST OF THE TIME.
THE MODEL CONSENSUS HAS SLIGHT CHANCE POPS FRIDAY/FRIDAY NIGHT AS
THE FIRST WEAK DISTURBANCE MOVES THROUGH THE AREA.
SATURDAY/SATURDAY NIGHT THE MODEL CONSENSUS HAS SLIGHT CHANCE TO
CHANCE POPS FOR MUCH OF THE AREA. THIS IS THE NEXT SIGNIFICANT STORM
SYSTEM THAT THE MODELS HAVE BEEN SUGGESTING FOR THE WEEKEND.
HOWEVER...THERE REMAINS QUESTIONS REGARDING HOW MUCH INTERACTION
THERE WILL BE BETWEEN THE NORTHERN AND SOUTHERN JETS. IF THE JETS
REMAIN SEPARATE...WHICH IS SUGGESTED BY THE OVERALL PATTERN...THEN
THIS STORM SYSTEM WOULD END UP BEING MUCH FURTHER SOUTH.
ADDITIONALLY...HOW FAST THE NEXT ARCTIC HIGH DROPS DOWN INTO THE
PLAINS AND UPPER MIDWEST WILL BE IMPORTANT. A FASTER ARRIVAL OF THE
ARCTIC HIGH WOULD ALSO SHUNT THE STORM SYSTEM FURTHER SOUTH.
SUNDAY THROUGH MONDAY THE MODEL CONSENSUS HAS DRY BUT COLD
CONDITIONS AS THE NEXT ARCTIC HIGH MOVES THROUGH THE MIDWEST.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z WEDNESDAY MORNING)
ISSUED AT 553 AM CST TUE FEB 17 2015
MOSTLY CLEAR SKIES AND VFR CONDITIONS WILL START OUT THE PERIOD...
FOLLOWED BY PERIODS OF LOW CLOUDS WITH MVFR CIGS AND FLURRIES BY
AFTERNOON THROUGH EVENING. ANOTHER COLD FRONT WILL CAUSE NORTHWEST
WINDS TO BECOME GUSTY AND INCREASE OVERNIGHT TONIGHT. THIS WILL
ALSO BRING A PERIOD OF LIGHT SNOW OR SNOW SHOWERS...ESPECIALLY TO
THE DBQ SITE IN THE EVENING. FOR NOW...THIS IS KEPT AS MVFR...BUT
THERE IS A POTENTIAL THAT CONDITIONS COULD LOWER TO IFR AT
DBQ...WHICH IS NOT INCLUDED IN THE CURRENT FORECAST. ALL SITES ARE
LIKELY TO SEE AT LEAST A PERIOD OF MVFR CONDITIONS OVERNIGHT
BEFORE IMPROVING TOWARD SUNRISE WEDNESDAY.
&&
.DVN WATCHES/WARNINGS/ADVISORIES...
IA...WIND CHILL ADVISORY FROM 3 AM TO NOON CST WEDNESDAY FOR BENTON-
BUCHANAN-CEDAR-CLINTON-DELAWARE-DUBUQUE-IOWA-JACKSON-
JOHNSON-JONES-LINN.
IL...NONE.
MO...NONE.
&&
$$
UPDATE...GIBBS
SYNOPSIS...SHEETS
SHORT TERM...SHEETS
LONG TERM...08
AVIATION...SHEETS
AREA FORECAST DISCUSSION
NWS GOODLAND KS
1226 AM MST TUE FEB 17 2015
.UPDATE...
ISSUED AT 706 PM MST MON FEB 16 2015
CURRENT FORECAST CONCERN WILL BE HOW FAR SOUTH CURRENT AREA OF
SNOW IN NORTHERN NEBRASKA GETS BEFORE DIMINISHING. H85-H7 LAPSE
RATES REMAIN FAVORABLE FOR THE NEXT 2 HOURS BUT BEGIN TO DECREASE
AFTER THAT. GIVEN THE CURRENT MOTION...DOUBTFUL ATMOSPHERE WILL BE
AS UNSTABLE BY THEN AND AM GOING TO LEAN TOWARDS PRECIP NOT MAKING
IT...BUT WILL KEEP AN EYE ON THINGS. OTHERWISE...ANOTHER ROUND OF
SNOW SHOWERS APPEARS POSSIBLE TOMORROW AND FINE TUNED POPS A BIT
TO HIGHLIGHT MOST LIKELY AREAS.
POTENTIAL FOR STRONG WINDS REMAINS...ALTHOUGH STRONGEST (50KT)
WINDS APPEAR TO BE ABOVE THE DRY ADIABATIC MIXED LAYER. WHILE A
PARCEL COULD POTENTIALLY MIX DOWN THE STRONGER WINDS...THINK IT IS
MORE LIKELY THAT CLOUDS AND SHOWERS WOULD LIMIT POTENTIAL FOR
BRINGING THESE WINDS INTO THE BOUNDARY LEVEL.
&&
.SHORT TERM...(THIS EVENING THROUGH TUESDAY)
ISSUED AT 208 PM MST MON FEB 16 2015
LATEST WV IMAGERY AND RAP UPPER LEVEL ANALYSIS SHOWS BROAD TROUGH
ACROSS THE EASTERN US WITH SHORTWAVE ALONG BASE OF TROUGH OVER
COLORADO. AT THE SURFACE LOW PRESSURE REMAINS IN PLACE OVER NORTH
CENTRAL KANSAS...WITH HIGH PRESSURE ACROSS THE NORTHERN ROCKIES
EXTENDING SOUTH TOWARDS NORTHERN COLORADO.
STEEP LOW LEVEL LAPSE RATES AND WEAK INSTABILITY HAVE LED TO
RAIN/SNOW SHOWER DEVELOPMENT THIS AFTERNOON ACROSS THE CWA.
GRAUPEL HAS BEEN OBSERVED WITH SOME OF THIS ACTIVITY. THIS
ACTIVITY WILL MAINLY BE TIED TO DAYTIME HEATING...QUICKLY ENDING
AS LOW LEVELS STABILIZE NEAR SUNSET. THERE WILL BE SOME WEAK
FORCING AROUND THE REGION OVERNIGHT...HOWEVER OTHER THAN MAYBE A
FEW FLURRIES IT DOESN`T APPEAR TO BE SUPPORTIVE OF MEASURABLE
PRECIP.
BETTER FORCING IS PROGGED TO MOVE THROUGH THE REGION BY 12Z
TUESDAY AS POSITIVE MID LEVEL VORTICITY ASSOCIATED WITH SHORTWAVE
TROUGH ROTATES INTO THE REGION. THIS WILL RESULT IN SHOWER
REDEVELOPMENT FROM THE NORTH TO THE SOUTH...INCREASING IN COVERAGE
AS LAPSE RATES STEEPEN WITH DAYTIME HEATING. I COULD SEE A
RAIN/SNOW/ICE PELLET MIX AGAIN LIKE TODAY...WITH MINIMAL TO NO
ACCUMULATIONS. UNIDIRECTIONAL GRADIENT AND WINDS ALOFT INCREASE
DURING THE DAY...AND IF WE WERE TO MIX TO 700MB WE COULD SEE
WARNING CRITERIA WINDS MIX TO THE SURFACE. MIXING HEIGHTS APPEAR
TO BE LIMITED DUE TO INCREASING CLOUD COVER...THOUGH THERMAL
PROFILES IN CLEAR SKIES COULD SUPPORT MUCH DEEPER MIXING. FOR NOW
I KEPT GUSTS 45-50MPH. THERE IS A CONCERN THAT SHOWERS COULD HELP
MIX STRONGER WINDS TO THE SURFACE. WINDS COULD ALSO COMBINE WITH
SHOWERS TO REDUCE VISIBILITIES.
.LONG TERM...(FRIDAY THROUGH MONDAY)
ISSUED AT 1209 AM MST TUE FEB 17 2015
PATTERN CHANGE WILL GET UNDERWAY AT THE BEGINNING OF THE PERIOD AS
A LONGWAVE TROUGH DIGS INTO THE CENTRAL CONUS. EVENTUALLY AN
UPPER LOW WILL PINCH OFF OVER THE GREAT BASIN AND A STRONG TROUGH
SETTLE INTO THE GREAT LAKES. BOTTOM LINE FOR THE CENTRAL HIGH
PLAINS WILL BE BELOW NORMAL TEMPERATURES AND OCCASIONAL CHANCES
FOR SNOW. THOSE SNOW CHANCES WILL BEGIN FRIDAY NIGHT AND CONTINUE
THROUGH MONDAY...WITH BEST CHANCES ON SATURDAY. ECMWF AND GFS
BOTH AGREE THAT THERE WILL BE SNOW...BUT HAVE HUGE DIFFERENCES IN
THE AMOUNTS. THE COLORADO FRONT RANGE WILL SEE THE MOST WITH GOOD
LOW LEVEL UPSLOPE FORECAST. BEST ESTIMATE AT THIS TIME WOULD BE A
MODERATE SNOWFALL IN THE 3 TO 6 INCH RANGE...HIGHEST AMOUNTS IN
EASTERN COLORADO...BUT CONFIDENCE IS LOW DUE TO AFOREMENTIONED
MODEL INCONSISTENCIES WITH AMOUNTS. THIS WILL NOT BE A CLOSED
UPPER LOW SITUATION SO WIND AND AND BLOWING SNOW DO NOT APPEAR TO
BE A THREAT AT THIS TIME. AS FOR TEMPERATURES...SUNDAY AND MONDAY
WILL BE THE COLDEST DAYS WITH TEMPERATURES NOT LIKELY GETTING OUT
OF THE 20S...THEN SOME MODEST WARMING TO START THE WEEK.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT)
ISSUED AT 1030 PM MST MON FEB 16 2015
VFR CONDITIONS WILL CONTINUE THROUGH 12Z WITH DECAYING SNOW
SHOWERS AROUND MCCOOK BRINGING A BRIEF 4000FT CIG TONIGHT...BUT NO
PREVAILING REDUCED FLIGHT CATEGORIES. CONFIDENCE HAS LOWERED A BIT
IN MVFR CIGS AROUND MCCOOK IN THE 12-18Z PERIOD...BUT GIVEN
EXPECTED T-TD SPREADS AND SNOW SHOWERS IN THE AREA AM GOING TO
KEEP THINGS AROUND 2500 FEET FOR A PORTION OF THE DAY. WINDS STILL
LOOK TO REMAIN STRONG FROM 15Z THROUGH 23Z WITH GUSTS EXCEEDING
40KTS DURING THE EARLY AFTERNOON.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
CO...NONE.
NE...NONE.
&&
$$
UPDATE...JRM
SHORT TERM...DR
LONG TERM...024
AVIATION...JRM
AREA FORECAST DISCUSSION
NWS GOODLAND KS
1038 PM MST MON FEB 16 2015
.UPDATE...
ISSUED AT 706 PM MST MON FEB 16 2015
CURRENT FORECAST CONCERN WILL BE HOW FAR SOUTH CURRENT AREA OF
SNOW IN NORTHERN NEBRASKA GETS BEFORE DIMINISHING. H85-H7 LAPSE
RATES REMAIN FAVORABLE FOR THE NEXT 2 HOURS BUT BEGIN TO DECREASE
AFTER THAT. GIVEN THE CURRENT MOTION...DOUBTFUL ATMOSPHERE WILL BE
AS UNSTABLE BY THEN AND AM GOING TO LEAN TOWARDS PRECIP NOT MAKING
IT...BUT WILL KEEP AN EYE ON THINGS. OTHERWISE...ANOTHER ROUND OF
SNOW SHOWERS APPEARS POSSIBLE TOMORROW AND FINE TUNED POPS A BIT
TO HIGHLIGHT MOST LIKELY AREAS.
POTENTIAL FOR STRONG WINDS REMAINS...ALTHOUGH STRONGEST (50KT)
WINDS APPEAR TO BE ABOVE THE DRY ADIABATIC MIXED LAYER. WHILE A
PARCEL COULD POTENTIALLY MIX DOWN THE STRONGER WINDS...THINK IT IS
MORE LIKELY THAT CLOUDS AND SHOWERS WOULD LIMIT POTENTIAL FOR
BRINGING THESE WINDS INTO THE BOUNDARY LEVEL.
&&
.SHORT TERM...(THIS EVENING THROUGH TUESDAY)
ISSUED AT 208 PM MST MON FEB 16 2015
LATEST WV IMAGERY AND RAP UPPER LEVEL ANALYSIS SHOWS BROAD TROUGH
ACROSS THE EASTERN US WITH SHORTWAVE ALONG BASE OF TROUGH OVER
COLORADO. AT THE SURFACE LOW PRESSURE REMAINS IN PLACE OVER NORTH
CENTRAL KANSAS...WITH HIGH PRESSURE ACROSS THE NORTHERN ROCKIES
EXTENDING SOUTH TOWARDS NORTHERN COLORADO.
STEEP LOW LEVEL LAPSE RATES AND WEAK INSTABILITY HAVE LED TO
RAIN/SNOW SHOWER DEVELOPMENT THIS AFTERNOON ACROSS THE CWA.
GRAUPEL HAS BEEN OBSERVED WITH SOME OF THIS ACTIVITY. THIS
ACTIVITY WILL MAINLY BE TIED TO DAYTIME HEATING...QUICKLY ENDING
AS LOW LEVELS STABILIZE NEAR SUNSET. THERE WILL BE SOME WEAK
FORCING AROUND THE REGION OVERNIGHT...HOWEVER OTHER THAN MAYBE A
FEW FLURRIES IT DOESN`T APPEAR TO BE SUPPORTIVE OF MEASURABLE
PRECIP.
BETTER FORCING IS PROGGED TO MOVE THROUGH THE REGION BY 12Z
TUESDAY AS POSITIVE MID LEVEL VORTICITY ASSOCIATED WITH SHORTWAVE
TROUGH ROTATES INTO THE REGION. THIS WILL RESULT IN SHOWER
REDEVELOPMENT FROM THE NORTH TO THE SOUTH...INCREASING IN COVERAGE
AS LAPSE RATES STEEPEN WITH DAYTIME HEATING. I COULD SEE A
RAIN/SNOW/ICE PELLET MIX AGAIN LIKE TODAY...WITH MINIMAL TO NO
ACCUMULATIONS. UNIDIRECTIONAL GRADIENT AND WINDS ALOFT INCREASE
DURING THE DAY...AND IF WE WERE TO MIX TO 700MB WE COULD SEE
WARNING CRITERIA WINDS MIX TO THE SURFACE. MIXING HEIGHTS APPEAR
TO BE LIMITED DUE TO INCREASING CLOUD COVER...THOUGH THERMAL
PROFILES IN CLEAR SKIES COULD SUPPORT MUCH DEEPER MIXING. FOR NOW
I KEPT GUSTS 45-50MPH. THERE IS A CONCERN THAT SHOWERS COULD HELP
MIX STRONGER WINDS TO THE SURFACE. WINDS COULD ALSO COMBINE WITH
SHOWERS TO REDUCE VISIBILITIES.
.LONG TERM...(TUESDAY NIGHT THROUGH MONDAY)
ISSUED AT 141 PM MST MON FEB 16 2015
WITH THE PASSAGE OF THE SHORTWAVE THRU THE CWA ON TUESDAY...THE TRI
STATE REGION WILL TREND INTO A DRY PERIOD FROM TUESDAY NIGHT RIGHT
INTO 12Z FRIDAY. DURING THIS TIMEFRAME...H5 RIDGE WILL FLATTEN SOME
OVER THE WESTERN PORTION OF THE COUNTRY...ALLOWING FOR WNW FLOW OVER
THE AREA. AT THE SURFACE...HIGH PRESSURE SLIDES SOUTH FROM CANADA
SHIFTING EAST THRU THE WEEK...AND A LEE-SIDE TROUGH SETS UP OVER THE
EASTERN SIDE OF THE ROCKIES. INCREASING WAA WILL RESULT AS SOUTHERLY
FLOW TAPS INTO WARMER AIR. FROM FRIDAY ON THRU NEXT MONDAY...
SHORTWAVE WILL PINWHEEL AROUND BROAD UPPER LOW TO THE EAST...SETTING
UP OVER THE ROCKIES. BLOCKING PATTERN OFF THE WEST COAST...AS WELL
AS OVER THE CENTRAL ATLANTIC OCEAN...KEEPS UPPER TROUGH OVER THE
ROCKIES. THIS SYSTEM WILL BE ABLE TO TAP INTO PACIFIC MOISTURE...
FEEDING IT INTO THE REGION FOR THE PERIOD. AT THE SURFACE HIGH
PRESSURE AGAIN BUILDING DOWN FROM CENTRAL CANADA WILL PROVIDE AN
EASTERLY/UPSLOPE FETCH INTO THE REGION. THE RESULT WILL BE CHANCE
POPS FOR -SW THRU THE ENTIRE FRIDAY THRU MONDAY TIMEFRAME WITH LIGHT
SCATTERED AMOUNTS. A WAA TREND FOR THE FIRST HALF OF THE EXTENDED
WILL GIVE WAY TO BELOW NORMAL NUMBERS WITH THE ARRIVAL OF THE COLD
CANADIAN RIDGE. OVERALL HIGHS WILL RANGE FROM THE 40S WEDNESDAY UP
TO NEAR 60F FOR THURS/FRI...THEN DROP DOWN INTO THE 20S TO L30S FOR
THE WEEKEND INTO NEXT MONDAY. OVERNIGHT LOWS WILL SEE BIG DROP AT
THE END OF THE WEEK WITH CANADIAN RIDGE OVER AREA. LOWS WILL RANGE
FROM THE TEENS AND MID 20S THRU FRIDAY NIGHT...THEN DOWN TO THE
TEENS AND SINGLE NUMBERS OVER THE UPCOMING WEEKEND.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT)
ISSUED AT 1030 PM MST MON FEB 16 2015
VFR CONDITIONS WILL CONTINUE THROUGH 12Z WITH DECAYING SNOW
SHOWERS AROUND MCCOOK BRINGING A BRIEF 4000FT CIG TONIGHT...BUT NO
PREVAILING REDUCED FLIGHT CATEGORIES. CONFIDENCE HAS LOWERED A BIT
IN MVFR CIGS AROUND MCCOOK IN THE 12-18Z PERIOD...BUT GIVEN
EXPECTED T-TD SPREADS AND SNOW SHOWERS IN THE AREA AM GOING TO
KEEP THINGS AROUND 2500 FEET FOR A PORTION OF THE DAY. WINDS STILL
LOOK TO REMAIN STRONG FROM 15Z THROUGH 23Z WITH GUSTS EXCEEDING
40KTS DURING THE EARLY AFTERNOON.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
CO...NONE.
NE...NONE.
&&
$$
UPDATE...JRM
SHORT TERM...DR
LONG TERM...JN
AVIATION...JRM
AREA FORECAST DISCUSSION
NWS JACKSON KY
1225 AM EST TUE FEB 17 2015
.UPDATE...
ISSUED AT 1225 AM EST TUE FEB 17 2015
UPDATED TO EXPIRE WESTERN SEGMENTS OF THE WINTER STORM WARNING AND
REPLACED IT WITH AN SPS TO HIGHLIGHT TREACHEROUS ROAD CONDITIONS
INTO THE DAY TUESDAY. ALSO UPDATED TO REMOVE POPS FROM OUR WESTERN
AREAS AS SNOW HAS ENDED. LOOKS LIKE SNOW SHOULD MOVE ON OUT BY 08Z
WITH THE LAST SEGMENTS OF THE WINTER STORM WARNING BEING ALLOWED
TO EXPIRE.
UPDATE ISSUED AT 1055 PM EST MON FEB 16 2015
THE BACK EDGE OF THE STEADIER SNOW OR FLURRIES HAS WORKED EAST OF
INTERSTATE 75 PER RADAR IMAGERY AND REGIONAL OBSERVATIONS.
HOWEVER...SOME ENHANCED RETURNS REMAIN IN THE FAR SOUTHEAST...BUT
THIS BAND SHOULD GRADUALLY MOVE INTO VA AND WV OVER THE NEXT HOUR.
NEAR TERM MODELS...SUCH AS THE HRRR RUNS HAVE ALL THE SNOW IN THE
FAR SOUTHEAST ENDING BY 7Z TO 8Z...OR 2 TO 3 AM. AT THIS TIME...WE
PLAN TO ALLOW THE WARNINGS TO RUN THEIR COURSE AND THEN REPLACE
WITH AN SPS FOR THE REMAINDER OF THE OVERNIGHT.
UPDATE ISSUED AT 755 PM EST MON FEB 16 2015
THE STEADIER SNOW HAS TAPERED OFF...BUT LIGHT TO MODERATE SNOW
REMAINS AND THERE ARE SOME ENHANCED AREAS OF REFLECTIVITY ACROSS
THE SOUTHEASTERN COUNTIES. THE THREAT FOR AT LEAST LIGHT SNOW WILL
REMAIN UNTIL THE UPPER LEVEL TROUGH MOVES THROUGH. EVEN WITH RATES
HAVING DECREASED...SNOW COVERED ROADS REMAIN AND EVEN ANY LIGHT
ADDITIONAL SNOW WILL IMPACT TRAVEL AND BEGIN TO FILL BACK IN ROADS
THAT HAVE BEEN PLOWED. ATTM...PLANS OUR TO LET THE WINTER STORM
WARNINGS WILL BE ALLOWED TO RUN THEIR COURSE.
&&
.SHORT TERM...(THIS EVENING THROUGH TUESDAY NIGHT)
ISSUED AT 415 PM EST MON FEB 16 2015
A WINTER STORM TRACKING ACROSS THE SOUTHEASTERN STATES WILL REACH
THE CAROLINA COASTLINE LATE TONIGHT AND THEN OFF THE EAST COAST
BY TUESDAY MORNING. A WESTERN RIDGE AND EASTERN TROUGH PATTERN IS
EXPECTED THROUGH MIDWEEK. A DEEP CLOSED LOW WILL DIVE SOUTH TOWARD
THE GREAT LAKES AND SOUTHERN ONTARIO AND BRING THE BEGINNING OF
ANOTHER ARCTIC BLAST LATE STARTING ON TUESDAY NIGHT. THIS WINTER
STORM IS BRINGING THE MOST WIDESPREAD IMPACTS AS FAR AS SNOWFALL
TO THE REGION IN THE LAST 10 TO 20 YEARS. IN MANY PLACES...THE
SNOW HAS BEEN ON THE DRIER SIDE...WHICH IS LIMITING POWER OUTAGE
POTENTIAL. SOME LOWER RATIO SNOW IS LIKELY FALLING CLOSER TO THE
VA AND TN BORDERS WHERE THE ATMOSPHERE IS WARMER. THIS LOW
THE WINTER STORM CONTINUES TO AFFECT THE REGION AND IT IS LEADING
TO TOTALS NEAR DOUBLE DIGITS IF NOT NEARLY A FOOT OR MORE ATTM.
AS THE SHORTWAVE TROUGH APPROACHES THE AREA THE LATEST SHORT TERM
GUIDANCE SUGGEST MODERATE TO HEAVY SNOW HANGING ON THROUGH LATE
EVENING WITH RATES OF 1 TO 2 INCH PER HOUR AT TIMES. LOCATIONS
NEAR THE TN AND VA BORDERS...SHOULD ALSO EXPERIENCE AN END TO MIX
WITH FREEZING RAIN AND SLEET. THE SNOW SHOULD WIND DOWN BY
MIDNIGHT OR 1 AM IN MOST LOCATIONS. AN ADDITIONAL TWO OR THREE TO
SEVEN INCHES SHOULD FALL THROUGH THE END OF THE EVENT.
A RIDGE OF HIGH PRESSURE WILL BRING A RESPITE TO THE SNOW CHANCES
AS THE LOW DEPARTS...BUT ADDITIONAL SNOW SHOWERS ARE POSSIBLE LATE
ON TUESDAY AS A WAVE TRACKS INTO THE MID SOUTH. THE THREAT FOR THE
SNOW SHOWERS WILL LINGER THROUGH THE END OF THE PERIOD AS AN
ARCTIC BOUNDARY APPROACHES AND CROSSES THE AREA. THE THREAT FOR
THESE SNOW SHOWERS WILL LINGER INTO THE LONG TERM PERIOD.
.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 355 PM EST MON FEB 16 2015
ALL EYES TURN TO A ARCTIC COLD FRONT DROPPING SOUTHEAST THROUGH
THE DAY ON WEDNESDAY. SPOKE OF UPPER LEVEL ENERGY FROM A QUASI
STATIONARY UPPER LEVEL CLOSED LOW ACROSS CANADA WILL BRING ARCTIC
AIR SOUTH INTO THE OHO VALLEY. THERE WILL BE SOME MOISTURE WITH
THIS FRONT AND COUPLED WITH SURFACE TO 3 KM LAPSE RATES 8 C/KM
BASED ON NAM...GIVEN THIS WOULD EXPECT THERE TO ONCE AGAIN BE SNOW
SQUALLS ACROSS THE REGION ESPECIALLY IN THE AFTERNOON ON
WEDNESDAY. THESE SQUALLS WILL BE ACCOMPANIED BY STRONG WINDS AND
WHITE OUT CONDITIONS. THIS UNSTABLE ATMOSPHERE PRESENTED BY THE
GUIDANCE WOULD ALSO SUPPORT ISOLATED THUNDERSNOW IN HEAVIER SNOW
SQUALLS. THIS INSTABILITY AND MOISTURE ARE PERSISTENT EVEN INTO
THE EVENING. BEHIND THIS FRONT EXPECT TEMPERATURES TO QUICKLY FALL
THROUGH THE EVENING WEDNESDAY INTO THE SINGLE DIGITS. THURSDAY
MORNING LOWS BOTTOM OUT INTO THE NEG SINGLE DIGITS WITH WIND
CHILLS WELL INTO THE NEG TEENS IN MANY SPOTS. THIS COLD AIR
PERSISTS THROUGH FRIDAY. HIGH PRESSURE TRIES TO BUILD EAST AND
FLOW AROUND THE HIGH COULD KEEP SOME MOISTURE ACROSS THE REGION
AND HAVE OPTED TO KEEP SOME FLURRIES. THIS HIGH PRESSURE WILL
PROGRESS EAST AND THEN WE START LOOKING AT THE NEXT SYSTEM MOVING
IN FOR THE WEEKEND. RIGHT NOW THERE CONTINUES TO BE A FAIR AMOUNT
OF UNCERTAINTY IN THE MODELS AT THIS POINT ON EXACTLY WHERE THE
ACCESS OF BEST QPF LINES UP. THAT SAID THE PROFILES ALSO SUPPORT
SNOW TO MIX AND RAIN THROUGH THE DAY ON SATURDAY. THERE CONTINUES
TO BE QUESTION AS TO PRECIP TYPE ALONG WITH HOW MUCH RAIN. THE
CONCERN WOULD CONTINUE TO BE HOW MUCH RAIN AND HOW MUCH SNOW
LINGERS GIVEN COLD TEMPERATURES UP TO THIS. RIGHT NOW KEPT CLOSE
TO SUPERBLEND IN THIS PART OF LONG TERM UNTIL BETTER AGREEMENT CAN
BE SEEN.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT)
ISSUED AT 1225 AM EST TUE FEB 17 2015
SOME LIGHT SNOW CONTINUES TO HOLD OVER FAR EASTERN KENTUCKY...BUT
THIS WILL BE ON THE WAY OUT OVER THE NEXT FEW HOURS. IN THE WAKE
OF THE SNOW...MVFR CIGS WILL LINGER...BORDERING ON IFR AT TIMES
THROUGH DAYBREAK. VFR CONDITIONS WILL TEMPORARILY MOVE BACK IN BY
MID MORNING TUESDAY WITH A GOOD DEAL OF SUNSHINE ANTICIPATED. OUR
NEXT WEATHER SYSTEM WILL MOVE IN LATE TUESDAY EVENING AND
ESPECIALLY OVERNIGHT WHICH WILL BRING THE THREAT OF LOW CIGS TO
THE AREA ONCE MORE.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
WINTER STORM WARNING UNTIL 3 AM EST EARLY THIS MORNING FOR
KYZ087-088-107-109-110-112-113-115-117>120.
&&
$$
UPDATE...KAS
SHORT TERM...JP
LONG TERM...DJ
AVIATION...KAS
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
442 PM EST TUE FEB 17 2015
.SHORT TERM...(THIS EVENING THROUGH WEDNESDAY)
ISSUED AT 354 PM EST TUE FEB 17 2015
12Z RAOBS/LATEST WV IMAGERY AND RUC ANALYSIS SHOW DEEP UPR TROF
CENTERED OVER SW HUDSON BAY DOWNSTREAM OF HI AMPLITUDE RDG ALONG THE
W COAST. H5/H7/H85 TEMPS UNDER THE CORE OF THE COLDEST AIR ARND NW
ONTARIO/NE MANITOBA ARE AS LO AS -46C/-33C/-30C RESPECTIVELY.
DESPITE CONSIDERABLE ICE COVER ON LK SUP...ESPECIALLY OVER THE W...
AND THE APRCH OF A WEAK SHRTWV RDG/SOME DNVA...SOME LES CONTINUES IN
THE SN BELTS IMPACTED BY THE COLD NW LLVL FLOW LEFT IN THE WAKE OF A
DISTURBANCE WHICH PASSED LAST NGT. THE MOST OPEN WATER IS LOCATED
OVER THE SCENTRAL PART OF THE LK...SO THE MORE NMRS SN SHOWERS ARE
MOVING INTO THE E HALF OF ALGER COUNTY. LOOKING UPSTREAM...THERE IS
A SHRTWV DIGGING SSEWD THRU MANITOBA. DESPITE PWAT UNDER 0.10
INCH...THERE IS A LARGE AREA OF CLD COVER AND SOME LIGHT SN UNDER
THE DPVA/DEEP LYR QVECTOR CNVGC AHEAD OF THIS SHRTWV WITH 00Z-12Z H5
HGT FALLS AOA 100M AND SOME FAIRLY DEEP MSTR THRU H7 DEPICTED ON THE
12Z YPL ROAB.
MAIN FCST CONCERNS IN THE SHORT TERM FOCUS ON GOING HEADLINES...LES
COVERAGE/AMOUNTS AND TEMPS/LO WIND CHILLS.
TNGT...DIGGING MANITOBA SHRTWV IS PROGGED TO TRACK SSEWD THRU MN AND
INTO WI...WITH DPVA/DEEP LYR QVECTOR CNVGC ON THE CYC SIDE OF THE
TRACK OF THIS FEATURE IMPACTING UPR MI. MODEL FCST SDNGS SHOW DCRSG
STABILITY/DEEPENING MSTR LATE TODAY OVER THE W AND THEN ESPECIALLY
NEAR THE WI BORDER CLOSER TO THE TRACK OF THE DISTURBANCE INTO THE
OVERNGT. WITH THE SHRTWV PASSAGE...THERE WL ALSO BE A REINFORCING
COLD FROPA/WSHFT TO THE NNW THAT IS FCST TO DRAG H85 TEMPS AS LO AS -
30C OVER THE W BY 12Z WED. EARLIER IN THE SEASON...THIS SETUP WOULD
HAVE PRESENTED AN OPPORTUNITY FOR SOME SGNFT LES. BUT CONSIDERABLE
ICE COVER OVER LK SUP AND ABSENCE OF DGZ WITH INFLUX OF BITTERLY
COLD AIR WL GREATLY LIMIT SN TOTALS. THE BEST CHC FOR SOME HEAVIER
LES WL BE IN ALGER COUNTY...WHICH WL BE DOWNWIND OF THE MORE OPEN
WATERS OVER SCENTRAL LK SUP AND IN AREA OF ENHANCED LLVL LAND BREEZE
TYPE CNVGC EXACERBATED BY THE ICE COVER ON LK SUP. BUT WSHFT FM THE
WNW TO NNW IN THE WAKE OF THE COLD FROPA WL SHIFT THE FOCUS FOR THE
MORE NMRS SN SHOWERS FM THE E HALF OF THE COUNTY TO AREAS ARND OR
JUST W OF MUNISING. ALTHOUGH THE DOWNSLOPE NATURE OF THE NW FLOW WL
LIMIT POPS OVER THE SCENTRAL...WL CARRY SOME SCHC/CHC POPS IN THAT
AREA TO ACCOUNT FOR THE PERIOD OF DEEPER HI RH AND DYNAMIC FORCING.
SINCE THE PRES GRADIENT WL TIGHTEN IN THE WAKE OF THE SHRWV
PASSAGE/COLD FROPA...H925 WINDS ARE FCST TO INCRS TO 20-25 KTS
OVERNGT. ALSO...GROWING ICE COVER ON LK SUP WL LIMIT MODERATION OF
THE INCOMING ARCTIC AIRMASS. THESE FACTORS WL RESULT IN AT LEAST
MARGINAL WIND CHILL ADVY CONDITIONS OVER MUCH OF THE W HALF OF UPR
MI AS THE H85 TEMP TUMBLES TOWARD -30C TOWARD 12Z. ALTHOUGH WIND
SPEEDS MAY BE MARGINAL FOR THE ADVY CRITERIA... OPTED TO MAINTAIN
THE GOING HEADLINES AND ADD BARAGA/MARQUETTE COUNTIES TO THE
HEADLINE.
WED...ARRIVAL OF DNVA/DEEP LYR QVECTOR DVGC/SUBSIDENCE IN THE WAKE
OF THE SHRTWV PASSAGE WL TEND TO SUPPRESS LINGERING SN SHOWERS
DOWNWIND OF LK SUP AND END THE PCPN COMPLETELY OVER THE SCENTRAL
DURING THE MRNG. AS THE FLOW BACKS A BIT TO THE NW AGAIN...ALGER
COUNTY WL REMAIN THE FOCUS FOR THE MORE NMRS AND HEAVIER SN
SHOWERS...ESPECIALLY IN THE MRNG. MAINTAINED WINTER WX HEADLINE FOR
ALGER COUNTY TNGT THRU WED AND WED NGT /SEE LONG TERM DISCUSSION.
WITH H85 TEMPS REMAINING NOT FAR FM -30C...EXPECT MAX TEMPS TO
STRUGGLE TO REACH ZERO...ESPCIALLY OVER THE NW HALF WHERE THE WIND
CHILL HEADLINE WL RUN UNTIL 18Z.
.LONG TERM...(WEDNESDAY NIGHT THROUGH TUESDAY)
ISSUED AT 440 PM EST TUE FEB 17 2015
THE OVERALL PATTERN WILL CONTINUE TO BE DOMINATED BY A MID/UPPER
LEVEL RIDGE FROM THE ERN PACIFIC INTO WRN CANADA AND A TROUGH FROM
HUDSON BAY INTO THE CENTRAL AND ERN CONUS. THIS WILL ALLOW ADDITIONAL
BOUTS OF COLD AIR TO MOVE INTO THE WRN LAKES INTO NEXT WEEK WITH
TEMPERATURES REMAINING WELL BELOW NORMAL.
WED NIGHT...THE MAIN FCST ISSUE CONTINUES TO BE THE VERY COLD AIR.
ALTHOUGH WINDS WILL GENERALLY BE LESS THAN 10 MPH...WITH AIR TEMPS
FALLING INTO THE -10 TO -20 RANGE...WIND CHILL VALUES COULD AGAIN
DROP INTO THE -20 TO -30 RANGE EVEN WITH THE WINDS ONLY AROUND 5 MPH.
THE HIGH RES MODELS WERE RELATIVELY CONSISTENT IN FOCUSING LES INTO
ALGER COUNTY DOWNSTREAM OF THE REMAINING OPEN PATCH OF WATER IN THE
DEEPEST PORTION OF LAKE SUPERIOR. FAVORABLE LOW LEVEL CONV IN THE
NARROW OPEN AREA COULD PRODUCE A HEAVIER SNOW BAND WITH ADDITIONAL
SNOW AMOUNTS IN THE 1 TO 4 INCH RANGE ARE EXPECTED.
HOWEVER...CONFIDENCE IS LOW GIVEN THE CHANGING/INCREASING AMOUNTS OF
ICE COVER.
THU AND THU NIGHT...THE ARCTIC HIGH WILL BUILD INTO THE AREA WITH
MAINLY LIGHT WINDS. EXPECT ENOUGH CLEARING FOR TEMPS TO DROP OFF
INTO THE -15 TO 25 RANGE WITH SOME LOCAL READINGS POSSIBLY DOWN TO
AROUND -30F. HOWEVER...MAINLY LIGHT/CALM WINDS SHOULD PREVAIL. ANY
REMAINING LES INTO ALGER COUNTY WILL DIMINISH AND LIFT OFFSHORE AS
WINDS BECOME SW BY EVENING.
FRI INTO FRI NIGHT...A TROUGH MOVING TOWARD THE WRN LAKES WILL
RESULT IN A BROAD WAA PATTERN THROUGH THE REGION. THE MODELS WERE IN
RELATIVELY GOOD AGREEMENT THAT DEEP LAYER ISENTROPIC ASCENT AHEAD
THIS FEATURES WILL PRODUCE SOME LIGHT SNOW. FOR NOW...POPS WERE LEFT
IN THE CHANCE RANGE...BUT WOULD EXPECT THAT IF THE TRENDS HOLD UP A
HIGHER POP LOW QPF/SNOW EVENT WILL DEVELOP WITH OVERALL SNOW AMOUNTS
OF AN INCH OR TWO. THE INCREASING SW FLOW OFF OF LAKE MICHIGAN COULD
BRING A SNOW BAND INTO THE FAR SE CWA BUT WITH THE EXTENSIVE ICE
THAT HAS DEVELOPED OVER NRN LAKE MI...CONFIDENCE IS LOW THAT IT WILL
BRING SIGNIFICANT ADDITIONAL SNOW AMOUNTS.
SAT-TUE...ANOTHER BATCH OF ARCTIC AIR WILL SLIDE INTO THE AREA BY
SUN WITH TEMPS FROM ZERO TO 10 BELOW SAT NIGHT AND IN THE SINGLE
DIGITS SUN. NW WINDS COULD BRING SOME LIGHT SNOW SHOWERS TO THE AREA
FROM ANY REMAINING GAPS IN THE ICE COVER...MAINLY OVER THE EAST
HALF. FCST UNCERTAINTY IS HIGHER BY TUE...AS THE 00Z/12Z ECMWF
REMAINED SIGNIFICANTLY MORE AGGRESSIVE WITH THE NEXT SHRTWV AND
AMOUNT OF COLD MOVING IN.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z WEDNESDAY AFTERNOON)
ISSUED AT 1225 PM EST TUE FEB 17 2015
DESPITE THE PRESENCE OF QUITE A BIT OF ICE COVER OVER WESTERN LK
SUP...EXPECT LES TO PERSIST THIS FCST PERIOD IN A COLD W TO NW FLOW
OF ARCTIC AIR. THE BEST CHC FOR THE SHSN/LOWER IFR VSBYS WL BE AT
CMX AND IWD...WHERE THE LLVL FLOW WL UPSLOPE...AND DURING THE
EVENING/EARLY OVERNGT HRS WHEN A REINFORCING COLD FNT WL SWING THRU
THE AREA. AT CMX...THERE MAY BE SOME IMPROVEMENT LATE WITH THE
DEPARTURE OF DEEPER MSTR AND A MORE UNFAVORABLE NNW WIND. ALTHOUGH
THE SN WILL NOT BE HEAVY...SMALL SN FLAKES ASSOCIATED WITH THE VERY
COLD AIR WL BE EFFICIENT AT REDUCING VSBY...SO IFR CONDITIONS ARE
LIKELY TO PERSIST AT IWD THRU THE ENTIRE PERIOD. DOWNSLOPE NATURE OF
THE FLOW WL LIMIT SN INTENSITY AT SAW...BUT MVFR CIGS ARE STILL
LIKELY TO PREDOMINATE WITH THE INCOMING DISTURBANCE/DEEPER MSTR.
&&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 354 PM EST TUE FEB 17 2015
WINDS WILL BE MAINLY 30 KTS OR LESS THE REST OF THE WEEK INTO NEXT
WEEKEND. THERE MAY BE A FEW GALE FORCE GUSTS IN THE VCNTY OF STRONG
BAND OF LAKE EFFECT SNOW OVER SCENTRAL LK SUPERIOR LATE TONIGHT
THROUGH WED NIGHT. HEAVY FREEZING SPRAY COULD DEVELOP IN THE LIMITED
OPEN WATER OF SCENTRAL LK SUPERIOR ON WED NIGHT. ICE COVERAGE WILL
CONTINUE TO EXPAND THROUGH THE WEEK AS ARCTIC AIRMASS SETTLES OVER
THE AREA.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
WINTER WEATHER ADVISORY UNTIL 7 AM EST THURSDAY FOR MIZ006.
WIND CHILL ADVISORY FROM 4 AM EST /3 AM CST/ TO 1 PM EST /NOON
CST/ WEDNESDAY FOR MIZ001>005-009>011-084.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...KC
LONG TERM...JLB
AVIATION...KC
MARINE...KC
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
356 PM EST TUE FEB 17 2015
.SHORT TERM...(THIS EVENING THROUGH WEDNESDAY)
ISSUED AT 354 PM EST TUE FEB 17 2015
12Z RAOBS/LATEST WV IMAGERY AND RUC ANALYSIS SHOW DEEP UPR TROF
CENTERED OVER SW HUDSON BAY DOWNSTREAM OF HI AMPLITUDE RDG ALONG THE
W COAST. H5/H7/H85 TEMPS UNDER THE CORE OF THE COLDEST AIR ARND NW
ONTARIO/NE MANITOBA ARE AS LO AS -46C/-33C/-30C RESPECTIVELY.
DESPITE CONSIDERABLE ICE COVER ON LK SUP...ESPECIALLY OVER THE W...
AND THE APRCH OF A WEAK SHRTWV RDG/SOME DNVA...SOME LES CONTINUES IN
THE SN BELTS IMPACTED BY THE COLD NW LLVL FLOW LEFT IN THE WAKE OF A
DISTURBANCE WHICH PASSED LAST NGT. THE MOST OPEN WATER IS LOCATED
OVER THE SCENTRAL PART OF THE LK...SO THE MORE NMRS SN SHOWERS ARE
MOVING INTO THE E HALF OF ALGER COUNTY. LOOKING UPSTREAM...THERE IS
A SHRTWV DIGGING SSEWD THRU MANITOBA. DESPITE PWAT UNDER 0.10
INCH...THERE IS A LARGE AREA OF CLD COVER AND SOME LIGHT SN UNDER
THE DPVA/DEEP LYR QVECTOR CNVGC AHEAD OF THIS SHRTWV WITH 00Z-12Z H5
HGT FALLS AOA 100M AND SOME FAIRLY DEEP MSTR THRU H7 DEPICTED ON THE
12Z YPL ROAB.
MAIN FCST CONCERNS IN THE SHORT TERM FOCUS ON GOING HEADLINES...LES
COVERAGE/AMOUNTS AND TEMPS/LO WIND CHILLS.
TNGT...DIGGING MANITOBA SHRTWV IS PROGGED TO TRACK SSEWD THRU MN AND
INTO WI...WITH DPVA/DEEP LYR QVECTOR CNVGC ON THE CYC SIDE OF THE
TRACK OF THIS FEATURE IMPACTING UPR MI. MODEL FCST SDNGS SHOW DCRSG
STABILITY/DEEPENING MSTR LATE TODAY OVER THE W AND THEN ESPECIALLY
NEAR THE WI BORDER CLOSER TO THE TRACK OF THE DISTURBANCE INTO THE
OVERNGT. WITH THE SHRTWV PASSAGE...THERE WL ALSO BE A REINFORCING
COLD FROPA/WSHFT TO THE NNW THAT IS FCST TO DRAG H85 TEMPS AS LO AS -
30C OVER THE W BY 12Z WED. EARLIER IN THE SEASON...THIS SETUP WOULD
HAVE PRESENTED AN OPPORTUNITY FOR SOME SGNFT LES. BUT CONSIDERABLE
ICE COVER OVER LK SUP AND ABSENCE OF DGZ WITH INFLUX OF BITTERLY
COLD AIR WL GREATLY LIMIT SN TOTALS. THE BEST CHC FOR SOME HEAVIER
LES WL BE IN ALGER COUNTY...WHICH WL BE DOWNWIND OF THE MORE OPEN
WATERS OVER SCENTRAL LK SUP AND IN AREA OF ENHANCED LLVL LAND BREEZE
TYPE CNVGC EXACERBATED BY THE ICE COVER ON LK SUP. BUT WSHFT FM THE
WNW TO NNW IN THE WAKE OF THE COLD FROPA WL SHIFT THE FOCUS FOR THE
MORE NMRS SN SHOWERS FM THE E HALF OF THE COUNTY TO AREAS ARND OR
JUST W OF MUNISING. ALTHOUGH THE DOWNSLOPE NATURE OF THE NW FLOW WL
LIMIT POPS OVER THE SCENTRAL...WL CARRY SOME SCHC/CHC POPS IN THAT
AREA TO ACCOUNT FOR THE PERIOD OF DEEPER HI RH AND DYNAMIC FORCING.
SINCE THE PRES GRADIENT WL TIGHTEN IN THE WAKE OF THE SHRWV
PASSAGE/COLD FROPA...H925 WINDS ARE FCST TO INCRS TO 20-25 KTS
OVERNGT. ALSO...GROWING ICE COVER ON LK SUP WL LIMIT MODERATION OF
THE INCOMING ARCTIC AIRMASS. THESE FACTORS WL RESULT IN AT LEAST
MARGINAL WIND CHILL ADVY CONDITIONS OVER MUCH OF THE W HALF OF UPR
MI AS THE H85 TEMP TUMBLES TOWARD -30C TOWARD 12Z. ALTHOUGH WIND
SPEEDS MAY BE MARGINAL FOR THE ADVY CRITERIA... OPTED TO MAINTAIN
THE GOING HEADLINES AND ADD BARAGA/MARQUETTE COUNTIES TO THE
HEADLINE.
WED...ARRIVAL OF DNVA/DEEP LYR QVECTOR DVGC/SUBSIDENCE IN THE WAKE
OF THE SHRTWV PASSAGE WL TEND TO SUPPRESS LINGERING SN SHOWERS
DOWNWIND OF LK SUP AND END THE PCPN COMPLETELY OVER THE SCENTRAL
DURING THE MRNG. AS THE FLOW BACKS A BIT TO THE NW AGAIN...ALGER
COUNTY WL REMAIN THE FOCUS FOR THE MORE NMRS AND HEAVIER SN
SHOWERS...ESPECIALLY IN THE MRNG. MAINTAINED WINTER WX HEADLINE FOR
ALGER COUNTY TNGT THRU WED AND WED NGT /SEE LONG TERM DISCUSSION.
WITH H85 TEMPS REMAINING NOT FAR FM -30C...EXPECT MAX TEMPS TO
STRUGGLE TO REACH ZERO...ESPCIALLY OVER THE NW HALF WHERE THE WIND
CHILL HEADLINE WL RUN UNTIL 18Z.
.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 529 AM EST TUE FEB 17 2015
STRONG UPPER LOW VCNTY OF NEWFOUNDLAND AND LABRADOR CANADA LIFTS
TOWARD GREENLAND. RESULT IS TROUGHING WITH BITTER COLD EXPANDING FM
NUNAVUT AND HUDSON BAY SOUTH TO THE GREAT LAKES THROUGH LATE THIS
WEEK. CORE OF COLDEST AIR WEDNESDAY INTO THURSDAY. TEMPS MODERATE
FRIDAY AND SATURDAY BEFORE ANOTHER BRIEFER SURGE OF COLDER AIR MOVES
IN LATER IN THE WEEKEND. SIGNS OF A MORE SIGNIFICANT MODERATION IN
TEMPS WAS EXPECTED FOR NEXT WEEK BUT MODELS HAVE TRENDED COLDER SO
THAT ANY MODERATION WOULD NOW BE SHORT LIVED.
LEADING COLD FRONT HAS MOVED THROUGH THE AREA THIS MORNING. SECOND
RE-INFORCING FRONT DUE BY DAYBREAK WEDNESDAY AS SHORTWAVE DROPPING
SOUTH OVER NORTHERN MANITOBA CURRENTLY MOVES ACROSS UPPER GREAT
LAKES. MAIN IMPACT FM THE SHORTWAVE/FROPA IS TO VEER WINDS MORE
NORTHERLY OVR LK SUPERIOR AND TO ADD MOISTURE AND LIFT BLO 10KFT
WHILE INCREASING INVERSIONS TOWARD 10KFT AND LAKE EQL/S NEARING
15KFT. OPEN WATER IS BECOMING A PREMIUM ON LK SUPERIOR WITH LATEST
NUMBERS SHOWING NEARLY 85 PCT OF LK SUPERIOR ICE COVERED. ONLY
APPRECIABLE AREA OF OPEN WATER IS OVER DEEPEST PORTION OF THE LAKE
CENTERED NORTH OF MUNISING...AND THAT IS SHRINKING AS WELL. GIVEN
THE EXTENT OF SFC CONVERGENCE THAT WILL BE PRESENT DUE TO THE
EXPANDING ICE COVER AND EMPHASIZED BY BITTER COLD AIRMASS OVER
REGION...A RELATIVELY NARROW BAND OF LAKE EFFECT SNOW SHOWERS IS
EXPECTED TO FOCUS OVER ALGER AND POSSIBLY NORTHERN SCHOOLCRAFT
COUNTIES WEDNESDAY INTO WEDNESDAY NIGHT. LAKE EFFECT CLOUD LAYER
WILL BE AT TEMPS LOWER THAN -20C. CONTINUE TO EXPECT VERY FINE
FLAKES THAT WILL BE VERY EFFECTIVE AT REDUCING VSBY BUT NOT VERY
GOOD AT ADDING UP TO MUCH SNOW ACCUMULATION. MIXED LAYER WINDS
WITHIN THE BAND TO AROUND 25 KTS SUGGEST GUSTY WINDS AND BLSN
ISSUES.
OVERALL...ADVY THROUGH WEDNESDAY NIGHT FOR ALGER COUNTY LOOKS ON
TRACK. GIVEN DEPTH OF LES AND ABUNDANCE OF SMALL FLAKES WITH SUCH
INSTABILITY...LOCATIONS THAT BECOME DIRECTLY INFLUENCED BY THE
HEAVIEST SNOW BAND WILL LIKELY EXPERIENCE WHITEOUT CONDITIONS. TOUGH
CALL TO SAY EXACTLY WHERE THAT WILL BE THOUGH. MESOSCALE MODELS
/NAM/GEM-REGIONAL AND NCEP WRF MODELS/ AND LOCAL WRF ALL POINT TO
MAIN BAND IMPACTING WESTERN OR CENTRAL ALGER COUNTY NEAR THE SHORE
THEN DRIFTING EAST LATER WEDNESDAY INTO WEDNESDAY NIGHT AS WINDS
BACK WITH ARRIVAL OF SFC HIGH IN THE PLAINS. OBVIOUSLY...WILL BE A
NEAR TERM/NOWCAST EVENT SINCE EVEN DOMINANT BANDS ARE RELATIVELY
NARROW.
MODELS CONTINUE TO SHOW SPOTTY LGT QPF OVER WESTERN COUNTIES. COULD
SEE FLURRIES OR VERY LGT SNOW SHOWERS WITH A FEW BREAKS IN THE ICE
SEEN MONDAY AFTN NEAR THE APOSTLE ISLANDS. GIVEN OVERALL EXTENT OF
BUILDING ICE COVERAGE WILL CONTINUE TO DOWNPLAY THE POPS AND REDUCE
INFLUENCE OF POPS/HIGHER SKY COVER FARTHER INLAND AS DRY ARCTIC HIGH
PRESSURE DRAWS CLOSER WEDNESDAY NIGHT INTO THURSDAY.
BITTER COLD WILL BE MAIN STORY FOR MOST OF UPR MICHIGAN. ONCE TEMPS
FALL BLO ZERO OVER WESTERN CWA ON TUESDAY NIGHT THEY MAY NOT REACH
ABOVE ZERO UNTIL FRIDAY. WIND CHILL ADVISORIES MAY BE NEEDED
WEDNESDAY NIGHT INTO THURSDAY MORNING...BUT IT IS NOT A SURE THING
AS WINDS MAY END UP LESS THAN 5 MPH OVER MOST OF THE CWA. EXCEPTION
WOULD BE RIGHT ALONG LK SUPERIOR SHORE WHERE WINDS WILL BE AROUND 10
MPH AND IT LOOKS JUST COLD ENOUGH FOR ADVY CRITERIA OF 25-35 BELOW
ZERO TO BE MET.
HIGH PRESSURE FIRMLY OVERHEAD ON THURSDAY/THURSDAY NIGHT. LES WILL
DRIFT OFFSHORE OF EASTERN CWA THURSDAY EVENING. WARM AIR ADVECTION
ALOFT BTWN THE HIGH AND LOW PRESSURE TROUGH MOVING OVER NORTHERN
PLAINS RESULTS IN HIGH CLOUDS AFTER MIDNIGHT...BUT HIGH AND LIGHT
WINDS SHOULD BE AROUND LONG ENOUGH INITIALLY IN THE EVENING TO LEAD
TO PLUMMETING TEMPS. LOWERED MINS INTO THE MID 20S BELOW ZERO AT
INTERIOR SPOTS OVER WEST. COLD ALL AREAS THOUGH WITH MINS OVER
ENTIRE CWA OF AT LEAST 10 BELOW. GENERALLY LGT WINDS INLAND BUT
ALONG LK SUPERIOR WINDS WILL BE STEADY ENOUGH TO RESULT IN WIND
CHILLS 25 TO 30 BELOW ZERO.
LOW PRESSURE TROUGH OVER THE NORTHERN PLAINS ON FRIDAY MORNING
CROSSES THE UPPER GREAT LAKES FRIDAY NIGHT INTO SATURDAY MORNING.
PERIOD OF LGT SNOW SHOULD ACCOMPANY THIS SYSTEM. SSW WINDS OFF LK
MICHIGAN MAY RESULT IN LAKE ENHANCEMENT FOR KISQ TO KERY. EXPANDING
ICE COVERAGE ON LK MICHIGAN MAY TEMPER THAT POTENTIAL THOUGH.
SOUNDINGS SHOW A LOT OF THE MOISTURE/LIFT FOR FRIDAY SYSTEM RESIDES
IN DGZ SO SLR/S PUSHING TOWARD 20:1 WILL BOOST THE SNOW
ACCUMULATIONS. MIXING RATIOS AT H7 HAVE TICKED UP SLIGHTLY WITH UP
TO 1.5G/KG FORECAST FRIDAY AFTN INTO FRIDAY EVENING. IF STRONGEST
FORCING DIRECTLY IMPACTS THE AREA...COULD SEE A FEW INCHES OF
SNOW...GREATEST OVER THE EASTERN CWA. BEHIND THIS SYSTEM...ANOTHER
SURGE OF COLD AIR SWEEPS THROUGH FOR SUNDAY. AIRMASS WILL BE DRY AND
THERE WILL BE MORE ICE COVER ON LK SUPERIOR THAN NOW. LES SHOULD BE
MINIMAL IN THE SNOW BELTS EAST OF MARQUETTE.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z WEDNESDAY AFTERNOON)
ISSUED AT 1225 PM EST TUE FEB 17 2015
DESPITE THE PRESENCE OF QUITE A BIT OF ICE COVER OVER WESTERN LK
SUP...EXPECT LES TO PERSIST THIS FCST PERIOD IN A COLD W TO NW FLOW
OF ARCTIC AIR. THE BEST CHC FOR THE SHSN/LOWER IFR VSBYS WL BE AT
CMX AND IWD...WHERE THE LLVL FLOW WL UPSLOPE...AND DURING THE
EVENING/EARLY OVERNGT HRS WHEN A REINFORCING COLD FNT WL SWING THRU
THE AREA. AT CMX...THERE MAY BE SOME IMPROVEMENT LATE WITH THE
DEPARTURE OF DEEPER MSTR AND A MORE UNFAVORABLE NNW WIND. ALTHOUGH
THE SN WILL NOT BE HEAVY...SMALL SN FLAKES ASSOCIATED WITH THE VERY
COLD AIR WL BE EFFICIENT AT REDUCING VSBY...SO IFR CONDITIONS ARE
LIKELY TO PERSIST AT IWD THRU THE ENTIRE PERIOD. DOWNSLOPE NATURE OF
THE FLOW WL LIMIT SN INTENSITY AT SAW...BUT MVFR CIGS ARE STILL
LIKELY TO PREDOMINATE WITH THE INCOMING DISTURBANCE/DEEPER MSTR.
&&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 354 PM EST TUE FEB 17 2015
WINDS WILL BE MAINLY 30 KTS OR LESS THE REST OF THE WEEK INTO NEXT
WEEKEND. THERE MAY BE A FEW GALE FORCE GUSTS IN THE VCNTY OF STRONG
BAND OF LAKE EFFECT SNOW OVER SCENTRAL LK SUPERIOR LATE TONIGHT
THROUGH WED NIGHT. HEAVY FREEZING SPRAY COULD DEVELOP IN THE LIMITED
OPEN WATER OF SCENTRAL LK SUPERIOR ON WED NIGHT. ICE COVERAGE WILL
CONTINUE TO EXPAND THROUGH THE WEEK AS ARCTIC AIRMASS SETTLES OVER
THE AREA.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
WINTER WEATHER ADVISORY UNTIL 7 AM EST THURSDAY FOR MIZ006.
WIND CHILL ADVISORY FROM 4 AM EST /3 AM CST/ TO 1 PM EST /NOON
CST/ WEDNESDAY FOR MIZ001>005-009>011-084.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...KC
LONG TERM...JLA
AVIATION...KC
MARINE...KC
AREA FORECAST DISCUSSION...UPDATED
NWS JACKSON MS
912 PM CST WED FEB 18 2015
.UPDATE...
EVENING UPPER/SFC ANALYSIS INDICATES DEEPENING LONG WAVE TROUGH OVER
MOST OF THE CENTRAL/ERN CONUS WITH A STRONG 1030MB SURFACE HIGH
MOVING INTO NW AR. FRONTAL BOUNDARY HAS MOVED INTO SRN MS NEAR THE
HWY 84 CORRIDOR WITH ANOTHER COLD FRONT MOVING INTO SRN MO/IL. THIS
SECOND BOUNDARY MAY BE SLIGHTLY WASHING OUT BUT GLOBAL MODELS/HRRR
INDICATES THIS BOUNDARY WILL MAKE IT INTO OUR AREA AND WILL INCREASE
CAA TONIGHT WITH A SLIGHTLY TIGHTER PRESSURE GRADIENT. HRRR INDICATES
SOME INCREASING WINDS ALSO DUE TO BAROCLINIC EFFECTS OF THE SNOWPACK
OFF TO THE NW IN SE AR/SRN TN AND THIS WILL INCREASE WINDS IN THE NRN
PARTS OF THE AREA CLOSE TO/AFTER 06Z. HRRR INDICATES DUE TO STRONGER
WINDS SOME LOWS BEING SLIGHTLY HIGHER. THUS ADJUSTED LOWS A COUPLE OF
DEGREES WARMER. DUE TO SOME WARMER LOWS...WIND CHILLS WILL NOT BE AS
COLD IN THE N AS THEY COULD BE BUT STILL POSSIBLY DIPPING NEAR TO
JUST BELOW 10 DEGREES. CONTEMPLATED WIND CHILL ADVISORY BUT DUE TO
SOME POTENTIAL FOR WARMER LOWS DUE TO STRONGER WINDS AND ONLY FALLING
TO OR JUST BELOW 10 DEGREES FOR A FEW HOURS FOR A LIMITED AREA...DID
NOT ISSUE A WIND CHILL ADVISORY FOR NOW. ADJUSTED HOURLY
TEMPS/DEWPOINTS/WIND CHILLS. REST OF THE FORECAST IS ON TRACK. /DC/
&&
.AVIATION...CONDITIONS SHOULD REMAIN VFR THROUGH TOMORROW AFTERNOON
ALTHOUGH SCATTERED CLOUDS...POSSIBLY EVEN AS LOW AS 3 KFT...COULD
MOVE THROUGH THE AREA DURING THIS TIME. WINDS WILL REMAIN FROM THE
NORTH AT ROUGHLY 5 TO 15 MPH. SOME MVFR CONDITIONS DUE TO CLOUD
COVER WILL BECOME MORE LIKELY LATE TOMORROW NIGHT WEST OF I-55 AS
CLOUDS INCREASE AHEAD OF AN INCOMING SYSTEM. /BB/
&&
.PREV DISCUSSION... /ISSUED 353 PM CST WED FEB 18 2015/
TONIGHT THROUGH THURSDAY NIGHT...EXPECT DRY WEATHER AND VERY COLD
TEMPS FOR TONIGHT AS ARCTIC HIGH PRESSURE BUILDS IN ACROSS THE
REGION. LOWS TONIGHT WILL FALL INTO THE LOWER TEENS NORTH TO LOWER
20S SOUTH. DRY WEATHER WILL CONTINUE THURSDAY AS HIGH PRESSURE
SETTLES IN. HIGH TEMPS WILL ONLY MAKE IT INTO THE LOWER 30S NE TO MID
40S SW. CLOUDS WILL BE ON THE INCREASE THU NIGHT AS THE HIGH MOVES
OFF TO THE EAST AND MOISTURE BEGINS TO MOVE IN OUT AHEAD OF THE NEXT
WEATHER SYSTEM. LOWS WILL RANGE FROM THE LOWER 20S NE TO THE MID 30S
SW. /27/
&&
.PRELIMINARY POINT TEMPS/POPS...
JACKSON 21 40 26 53 / 0 0 4 32
MERIDIAN 19 40 22 49 / 0 0 3 21
VICKSBURG 23 41 30 58 / 0 0 5 39
HATTIESBURG 24 46 26 58 / 0 0 4 14
NATCHEZ 25 46 34 61 / 0 0 4 28
GREENVILLE 19 35 24 44 / 0 0 8 57
GREENWOOD 17 35 24 43 / 0 0 7 52
&&
.JAN WATCHES/WARNINGS/ADVISORIES...
MS...NONE.
LA...NONE.
AR...NONE.
&&
$$
DC/BB/27
AREA FORECAST DISCUSSION...UPDATED AVIATION
NWS ST LOUIS MO
1237 PM CST Tue Feb 17 2015
.UPDATE:
Issued at 656 AM CST Tue Feb 17 2015
Latest few runs of the RAP model continue to focus in on southern
Missouri and southern Illinois counties for the heaviest snowfall
late this afternoon and this evening. The model is much more
robust with QPF and is supported by the latest 4km Local WRF with
around 0.25 inches in a band from Shannon County Missouri through
Reynolds, Iron and Madison. Have increasing confidence of the
main band location so have went ahead and increased POPs to
categorical and inched QPF/snowfall up a little more, but not to
the extend that the latest RAP suggests. I also expanded chance POPs
this evening further north into the St. Louis Metro as a stronger
shortwave would also lead to a more broad lighter snow shield to
develop north of the heaviest band ahead of the shortwave. In fact
the latest RAP suggests up to an inch as far north as the Missouri
River. Will brief oncoming dayshift of the trends in the short
term model guidance and the potential need for an advisory across
the far southern counties of the CWA late this afternoon and this
evening.
CVKING
&&
.SHORT TERM: (Through Late This Afternoon)
Issued at 332 AM CST Tue Feb 17 2015
Next shortwave helping to dig out the upper level trof across the
eastern 2/3rds of the CONUS will bring another shot of accumulating
snow across mainly the southern zones of the CWA this afternoon and
this evening. Used a model consensus approach for location of POPs
and increased them into the likely category. Dayshift will need to
fine tune and increase to categorical once the band of snow begins
to develop. Certainly appears that there will be enough lift and
moisture to justify increasing snowfall amounts a tad as well with
up to two inches possible within the band of snow. Otherwise,
temperatures today will respond nicely ahead of the approaching cold
front from the north, with highs ranging from the 20s north to the
30s south.
CVKING
.LONG TERM: (Tonight through Monday)
Issued at 332 AM CST Tue Feb 17 2015
(Wednesday through Thursday)
Focus thru this period will be temps with little in the way of
precip currently anticipated.
Have kept dry PoPs going for Wed attm. Given progd soundings thru
Wed, expect flurries to be possible throughout the day. However, it
seems plausible that bands will be possible where more than just
flurries may be possible. This, of course, is a short term forecast
issue.
Otherwise, only minor changes to temps have been made as prev
forecast still appears to be on track. Continued the cold trend, aob
coldest guidance at most times especially overnight. Mdls are in
good agreement with the sfc ridge building into the area Wed night.
As clouds clear out of the region, temps shud drop quickly with
snowpack across the region. Thurs shud be slightly warmer across
most of the CWA as the sfc ridge builds ewd and thermal ridge
approaches the area.
(Friday through Monday)
Overall, not a lot of change from the prev forecast thru the extd.
Mdls continue to indicate the potential for another measurable SN
event Thurs night into Fri. Mdls are in somewhat good agreement with
a s/w embedded within the NW flow Thurs night, with good low and mid
level frontogenesis. Mdls have come into slightly better agreement
and have raised PoPs a bit. However, questions remain regarding
exactly where this precip band may set up.
As the deep upper low finally pulls newd out into the nrn Atlantic,
flow become much more zonal this weekend with the next trof digging
into wrn U.S. Mdl spread increases with individual s/ws thru the
extd. The GEM becomes an outlier thru much of this period and have
trended away from this soln.
However, mdls are in relatively good agreement with a sfc low
developing with an associated trof on Sat. Increased PoPs across
mainly srn portions of the region. While mdl thermal profiles are
currently in close agreement, this may change as the system
approaches. Believe it was prudent to add another p-type as current
trends suggest that many p-types will be possible or probable.
However, have currently only added IP to the forecast as this is the
other dominant p-type currently expected. As the thermal ridge
builds into the area, it is very possible that precip will change
from SN, to IP, to FZRA to RA and back again during this event. Will
leave these details to future forecasts as confidence builds and
mdls come into better agreement.
Beyond this system, mdls build another ridge into the region,
bringing colder temps. However, current indications are that this
ridge will not be as cold as earlier this week.
Tilly
&&
.AVIATION: (For the 18z TAFs through 18z Wednesday Afternoon)
Issued at 1208 PM CST Tue Feb 17 2015
Cold front extending from northern MI southwest through STL and
COU will continue moving southeastward with the surface wind
becoming nwly behind the front. Areas of low level clouds around
3000-6000 feet will continue to advect southeastward through the
area this afternoon and tonight. An upper level disturbance will
move east-southeastward through the area tonight, while a
secondary cold front moves southeastward through the taf sites
late tonight and Wednesday morning. Some light snow can be
expected this evening, mainly south of the taf sites, although
flurries or a brief period of light snow is possible further
north. For now will just include flurries in the tafs with no
visibility restrictions. The surface wind will strengthen and
become gusty Wednesday morning after passage of the secondary cold
front. The cloud ceilings may lower into the MVFR catagory as well
Wednesday morning after fropa.
Specifics for KSTL: Low level, VFR cloudiness will continue to
advect southeastward through STL this aftenoon and tonight, with
cigs likely dropping down to the MVFR catagory Wednesday morning.
There may be a brief period of light snow this evening, but for
now will just include flurries in the STL TAF tonight with no
visibility restrictions. Light surface wind should become nwly
later this afternoon, then become relatively strong and gusty
after the passage of a second cold front Wednesday morning.
GKS
&&
.LSX WATCHES/WARNINGS/ADVISORIES:
MO...NONE.
IL...NONE.
&&
$$
WFO LSX
AREA FORECAST DISCUSSION...UPDATED
NWS ST LOUIS MO
702 AM CST Tue Feb 17 2015
.UPDATE:
Issued at 656 AM CST Tue Feb 17 2015
Latest few runs of the RAP model continue to focus in on southern
Missouri and southern Illinois counties for the heaviest snowfall
late this afternoon and this evening. The model is much more
robust with QPF and is supported by the latest 4km Local WRF with
around 0.25 inches in a band from Shannon County Missouri through
Reynolds, Iron and Madison. Have increasing confidence of the
main band location so have went ahead and increased POPs to
categorical and inched QPF/snowfall up a little more, but not to
the extend that the latest RAP suggests. I also expanded chance POPs
this evening further north into the St. Louis Metro as a stronger
shortwave would also lead to a more broad lighter snow shield to
develop north of the heaviest band ahead of the shortwave. In fact
the latest RAP suggests up to an inch as far north as the Missouri
River. Will brief oncoming dayshift of the trends in the short
term model guidance and the potential need for an advisory across
the far southern counties of the CWA late this afternoon and this
evening.
CVKING
&&
.SHORT TERM: (Through Late This Afternoon)
Issued at 332 AM CST Tue Feb 17 2015
Next shortwave helping to dig out the upper level trof across the
eastern 2/3rds of the CONUS will bring another shot of accumulating
snow across mainly the southern zones of the CWA this afternoon and
this evening. Used a model consensus approach for location of POPs
and increased them into the likely category. Dayshift will need to
fine tune and increase to categorical once the band of snow begins
to develop. Certainly appears that there will be enough lift and
moisture to justify increasing snowfall amounts a tad as well with
up to two inches possible within the band of snow. Otherwise,
temperatures today will respond nicely ahead of the approaching cold
front from the north, with highs ranging from the 20s north to the
30s south.
CVKING
.LONG TERM: (Tonight through Monday)
Issued at 332 AM CST Tue Feb 17 2015
(Wednesday through Thursday)
Focus thru this period will be temps with little in the way of
precip currently anticipated.
Have kept dry PoPs going for Wed attm. Given progd soundings thru
Wed, expect flurries to be possible throughout the day. However, it
seems plausible that bands will be possible where more than just
flurries may be possible. This, of course, is a short term forecast
issue.
Otherwise, only minor changes to temps have been made as prev
forecast still appears to be on track. Continued the cold trend, aob
coldest guidance at most times especially overnight. Mdls are in
good agreement with the sfc ridge building into the area Wed night.
As clouds clear out of the region, temps shud drop quickly with
snowpack across the region. Thurs shud be slightly warmer across
most of the CWA as the sfc ridge builds ewd and thermal ridge
approaches the area.
(Friday through Monday)
Overall, not a lot of change from the prev forecast thru the extd.
Mdls continue to indicate the potential for another measurable SN
event Thurs night into Fri. Mdls are in somewhat good agreement with
a s/w embedded within the NW flow Thurs night, with good low and mid
level frontogenesis. Mdls have come into slightly better agreement
and have raised PoPs a bit. However, questions remain regarding
exactly where this precip band may set up.
As the deep upper low finally pulls newd out into the nrn Atlantic,
flow become much more zonal this weekend with the next trof digging
into wrn U.S. Mdl spread increases with individual s/ws thru the
extd. The GEM becomes an outlier thru much of this period and have
trended away from this soln.
However, mdls are in relatively good agreement with a sfc low
developing with an associated trof on Sat. Increased PoPs across
mainly srn portions of the region. While mdl thermal profiles are
currently in close agreement, this may change as the system
approaches. Believe it was prudent to add another p-type as current
trends suggest that many p-types will be possible or probable.
However, have currently only added IP to the forecast as this is the
other dominant p-type currently expected. As the thermal ridge
builds into the area, it is very possible that precip will change
from SN, to IP, to FZRA to RA and back again during this event. Will
leave these details to future forecasts as confidence builds and
mdls come into better agreement.
Beyond this system, mdls build another ridge into the region,
bringing colder temps. However, current indications are that this
ridge will not be as cold as earlier this week.
Tilly
&&
.AVIATION: (For the 12z TAFs through 12z Wednesday Morning)
Issued at 516 AM CST Tue Feb 17 2015
Shortwave and attendant cold front will bring a wind shift and
chance of flurries or light snow to the terminals today. The cold
front should be through KUIN by 12Z and arrive during the lunch
hour at KCOU and the St. Louis Metro terminals. The cold front
will cause winds to shift from west to northwest. The upper level
disturbance (shortwave) will sweep across the region later this
afternoon and this evening with the greatest potential of
accumulating snow remaining south of the terminals across southern
Missouri and Illinois. At this time only expect flurries or very
light snow to be observed at the terminals. The wind will actually
back to the west again overnight ahead of an even stronger cold
front that is progged to arrive Wednesday morning. Gusty northwest
winds will accompany this secondary cold front.
Specifics for KSTL:
Have the front timed through St. Louis around 21Z with flurries or
very light snow lasting into the evening hours. Stronger front
arrives 12Z on Wednesday with coldest air of the season.
CVKING
&&
.LSX WATCHES/WARNINGS/ADVISORIES:
MO...NONE.
IL...NONE.
&&
$$
WFO LSX
AREA FORECAST DISCUSSION
NWS BILLINGS MT
247 PM MST TUE FEB 17 2015
.SHORT TERM...VALID FOR WED AND THU...
AN AREA OF LIGHT SNOW SHOWERS STILL HANGING ON FROM ROUNDUP TO
FORT SMITH TO SHERIDAN. AREA RESPONDING TO A WEAK BAROCLINIC ZONE
AND JET DYNAMICS. HRRR LINGERS THIS ACTIVITY THROUGH THE EVENING.
ADDED SOME LOW POPS TONIGHT AS MOISTURE LOOKS RATHER LIMITED. WARM
AIR ALOFT OVERNIGHT WILL CAUSE ACTIVITY TO SHIFT EAST AND BECOME
MORE FLURRIES...SO ADDED LATE TONIGHT INTO WEDNESDAY.
WARMER TEMPERATURES IN STORE FOR WEDNESDAY AS THE RIDGE TO THE
WEST SHIFTS EAST AND FLATTENS OUT. DOWNSLOPE FLOW WILL DRY US OUT
AND ALLOW HIGHS TO REACH THE UPPER 40S TO LOWER 50S OVER WESTERN
AND CENTRAL ZONES. THE EAST WILL BE A LITTLE COOLER AS THE SURFACE
TROUGH DOES NOT QUITE CLEAR THE STATE. WINDS WILL PICK UP OVER THE
WEST WEDNESDAY AFTERNOON AND NIGHT. 700MB WINDS REACH 45KTS AND
LOCAL GUIDANCE TOOLS INDICATE WINDS SHOULD STAY BELOW HIGHLIGHT
CRITERIA...SO LEFT WIND HIGHLIGHTS ON THE SIDELINE. THAT BEING
SAID...SHOULD BE WINDY AND MAINTAINED STRONG WIND GUSTS MENTIONED
IN THE GRIDS.
THE SURFACE TROUGH WILL SLIDE INTO THE DAKOTAS WEDNESDAY NIGHT
AND THURSDAY AND ALLOW ALL LOCATIONS TO EXPERIENCE ABOVE SEASONAL
TEMPERATURES. WEAK ENERGY SLIPS ACROSS THE AREA...BUT WILL BE
STARVED FOR MOISTURE DURING THE DAY. DEEPER MOISTURES FLOWS INTO
THE FORECAST AREA THURSDAY NIGHT BEHIND THE INITIAL WAVE...SO KEPT
POPS IN THEN. TWH
.LONG TERM...VALID FOR FRI...SAT...SUN...MON...TUE...
AN UPPER LEVEL TROUGH WILL MOVE SOUTH ACROSS IDAHO INTO UTAH
FRIDAY. AS IT DOES...IT WILL DROP ANOTHER COLD FRONT ACROSS OUR
FORECAST AREA USHERING IN GUSTY NORTHERLY WINDS. THIS WILL RESULT
IN AN UNSTABLE NORTH TO NORTHWEST FLOW ALOFT DURING THE DAY AND
CONTINUING THROUGH SATURDAY. SCATTERED RAIN AND SNOW SHOWERS
FRIDAY WILL CHANGE TO ALL SNOW FRIDAY EVENING/NIGHT. THE MOST
FAVORED AREAS FOR ACCUMULATING SNOW WILL BE THE MOUNTAIN
LOCATIONS...AS WELL AS THE BEARTOOTH/ABSAROKA FOOTHILLS. THIS
INITIAL COLD FRONT WILL NOT BE TOO COLD WITH THE COLDER AIR THOUGH
BEING ACROSS OUR FAR EASTERN AREAS. HOWEVER...A SECONDARY SHOT OF
COLD AIR MOVES SOUTH AND FURTHER WEST LATE IN THE DAY SATURDAY
INTO SUNDAY BRINGING ANOTHER CHANCE FOR LIGHT SNOW TO THE FORECAST
AREA. TEMPERATURES FRIDAY WILL BE AT OR SLIGHTLY ABOVE NORMAL
BEFORE DROPPING BELOW NORMAL SATURDAY AND SUNDAY.
HIGH PRESSURE RIDGING BUILDS BACK ACROSS THE FORECAST AREA MONDAY
BRINGING WARMER TEMPERATURES. HOWEVER...THIS LOOKS TO BE SHORT-
LIVED AS ANOTHER DISTURBANCE WILL MOVE SOUTHEAST OUT OF CANADA
ALONG WITH A COLD FRONT LATE TUESDAY/TUESDAY NIGHT BRINGING
ANOTHER CHANCE FOR SNOW ALONG WITH COLDER TEMPERATURES. HOOLEY
&&
.AVIATION...
LIGHT SNOW SHOWERS WILL CONTINUE THROUGH 06Z ACROSS THE CENTRAL
AND SOUTHERN AREAS...MAINLY IMPACTING KSHR WHERE OCCASIONAL MVFR
CONDITIONS WILL BE POSSIBLE. THE MOUNTAINS AND FOOTHILLS AREAS
WILL BE OBSCURED AT TIMES ESPECIALLY ACROSS THE BIG HORN
MOUNTAINS. ELSEWHERE...VFR CONDITIONS WILL PREVAIL THROUGH THIS
EVENING AND OVERNIGHT HOURS. HOOLEY
&&
.PRELIMINARY POINT TEMP/POPS...
WED THU FRI SAT SUN MON TUE
-----------------------------------------------------------
BIL 020/048 033/056 033/046 027/032 014/032 021/043 027/045
10/B 01/N 23/O 44/S 21/B 12/O 22/O
LVM 024/053 035/054 034/043 025/035 013/033 020/043 029/048
00/N 01/N 24/O 46/S 32/S 12/O 22/R
HDN 017/042 026/053 028/045 025/031 012/031 017/041 024/043
21/E 01/B 23/O 44/S 21/B 12/S 22/O
MLS 007/030 019/045 025/040 020/025 007/027 017/038 019/038
01/M 11/B 23/O 32/S 21/B 12/S 22/S
4BQ 009/031 021/048 026/043 022/029 009/028 016/041 021/040
11/M 01/B 23/O 33/S 21/B 02/S 22/O
BHK 903/024 013/039 024/037 015/020 002/023 013/035 016/034
01/B 12/W 23/O 32/S 10/U 02/S 22/S
SHR 015/041 024/052 026/041 022/029 009/027 011/040 022/042
20/B 01/B 24/O 45/S 32/S 12/S 22/O
&&
.BYZ WATCHES/WARNINGS/ADVISORIES...
MT...NONE.
WY...NONE.
&&
$$
WEATHER.GOV/BILLINGS
AREA FORECAST DISCUSSION...UPDATED
NWS BILLINGS MT
1144 AM MST TUE FEB 17 2015
.UPDATE...
CANCELLED THE REMAINDER OF THE WINTER WEATHER ADVISORIES.
ACTIVITY HAS DECREASED TO A SCATTERED LIGHT SNOW SHOWERS. TWH
&&
.SHORT TERM...VALID FOR TDY AND WED...
SNOW SHOWER ACTIVITY EARLY THIS MORNING WILL GRADUALLY WANE TODAY
AND LEAD TO A DRIER WEATHER PATTERN TONIGHT AND WEDNESDAY.
A NARROW BAND OF RELATIVELY INTENSE SNOW FORMED AFTER MIDNIGHT IN
CENTRAL YELLOWSTONE COUNTY AND WAS CENTERED ACROSS THE BILLINGS
HEIGHTS WHERE SPOTTERS HAVE REPORTED UP TO 3 INCHES OF SNOW AS OF
300 AM MST. THIS BAND FORMED IN UNSTABLE NORTHWEST FLOW ALOFT...
AND WAS ENHANCED IN THE VICINITY OF A WEAK SURFACE WIND SHIFT. IT
WAS VERY NARROW /LESS THAN 5 MILES WIDE/ AND THUS VERY DIFFICULT
TO ANTICIPATE RIGHT UP UNTIL RADAR BEGAN TO SUPPORT ITS FORMATION.
SOME VERY RECENT RADAR TRENDS AS OF 330 AM MST SUGGEST THE BAND
IS WEAKENING...SO ADDITIONAL ACCUMULATION IN THE CITY THROUGH
EARLY THIS MORNING WILL LIKELY BE LESS THAN AN INCH.
OTHERWISE...SNOW SHOWER ACTIVITY IS ALSO CONTINUING OVER FAR SOUTH
CENTRAL MT AND NORTH CENTRAL WY AS OF 330 AM MST...AND OVERNIGHT
MODEL TRENDS SUGGEST IT WILL LINGER THROUGH THE MORNING. HRRR RUNS
EVEN HANG ONTO SNOW IN THE FORT SMITH AND SHERIDAN AREA RIGHT INTO
THE AFTERNOON...THOUGH WITH DECREASING INTENSITY IN TIME. WE THUS
EXTENDED THE WINTER WEATHER ADVISORY FOR BIG HORN...SOUTHERN ROSE-
BUD AND SHERIDAN COUNTIES AND THE NORTHEAST BIGHORN MOUNTAINS OUT
UNTIL NOON MST TODAY. ADDITIONAL ACCUMULATIONS SHOULD ONLY BE ONE
OR TWO INCHES...BUT ROADS WILL REMAIN SLIPPERY AND SNOW COVERED.
BY THIS EVENING...THE AIR MASS WILL BE STABILIZING AS THE HEIGHTS
ALOFT RISE. WE THUS HAVE A DRY FORECAST IN PLAY OVERNIGHT TONIGHT
AND INTO WEDNESDAY...THOUGH AS WARM AIR ADVECTION ALOFT GETS GOING
THERE ARE HINTS IN SOME 00 UTC GUIDANCE FOR VERY LIGHT SNOW ACROSS
SOUTHEASTERN MT TONIGHT INTO WEDNESDAY. FORECAST SOUNDINGS SUGGEST
SATURATION WILL BE LIMITED IN THE NEAR-SURFACE LAYER THOUGH AND SO
WE KEPT WITH THE IDEA OF A DRY FORECAST FOR NOW.
HIGHS TODAY WILL BE COOL...RANGING FROM THE TEENS EAST AND PERHAPS
IN AREAS WHERE SNOW COVER IS GREATEST TO THE 30S F ACROSS SOUTH
CENTRAL MT. WARMING WILL BEGIN IN EARNEST WEDNESDAY ACROSS SOUTH
CENTRAL MT WITH HIGHS IN THE 50S F IN THE FOOTHILLS...BUT MIXING
WILL BE LIMITED FURTHER EAST IN SOUTHEASTERN MT WITH CLOUD COVER
AND LIGHT SOUTHEAST WINDS AHEAD OF A DEVELOPING WARM FRONT. HIGHS
WILL THUS STAY IN THE 20S F WEDNESDAY ACROSS FAR SOUTHEASTERN MT
AND IN FACT OUR FORECAST BE OPTIMISTIC IN SPOTS. SCHULTZ
.LONG TERM...VALID FOR THU...FRI...SAT...SUN...MON...
THURSDAY WILL BE MILD BEHIND A PACIFIC FRONTAL PASSAGE...WITH
FAIRLY STRONG WEST WINDS ALONG OUR FOOTHILLS ESPECIALLY IN THE
MORNING. OUR WEST AND CENTRAL PARTS SHOULD BE WELL-MIXED AND SEE
TEMPS RISE INTO THE 50S...BUT LATEST MODEL RUNS SUGGEST THE SFC
TROF MAY NOT PUSH ALL THE WAY TO THE DAKOTAS...KEEPING PLACES LIKE
BAKER AND EKALAKA COLDER THAN THE REST OF THE CWA. WILL NEED TO
KEEP AN EYE ON THE WINDS AS THE USUAL FOOTHILL LOCATIONS SHOULD
SEE GUSTS TO 50 MPH.
CONFIDENCE CONTINUES TO INCREASE IN A SURGE OF COLD CANADIAN AIR
BY THE END OF THE WEEK. COLD ADVECTION WILL ACTUALLY BEGIN
FRIDAY...IE MAYBE A COMBINATION OF RAIN AND SNOW SHOWERS ON THIS
DAY WITH SHORTWAVE ENERGY FROM THE NW. INTERESTING FACET OF THIS
HIGHLY AMPLIFYING FLOW IS THE POSITIVELY TILTED NATURE OF THE TROF
AS IT PUSHES TOWARD THE NORTHERN GREAT BASIN...WITH STRONG UPPER
RIDGING OFF THE PAC COAST INTO BRITISH COLUMBIA. THIS SHOULD ALLOW
FOR STRONG CANADIAN SFC RIDGING OVER EASTERN MT...WHICH ALL MODELS
SHOW HAPPENING...WITH PRESSURES TO NEAR 1050MB OVER NORTH DAKOTA
BY 12Z SUNDAY PER THE GFS ENSEMBLE MEAN. AS A RESULT WE ARE
LOOKING AT A COUPLE OF FAIRLY COLD DAYS SATURDAY AND SUNDAY.
MODELS STILL DIFFER IN MAGNITUDE OF COLD...SOME SUGGEST 850MB
TEMPS NEAR -20C BY EARLY SUNDAY...WHICH WOULD BE THE COLDEST WE
HAVE SEEN IN QUITE SOME TIME. MAIN FORECAST ADJUSTMENTS WERE TO
RAISE POPS FOR WHAT WILL BE SNOWFALL FRIDAY NIGHT AND SATURDAY...
THIS IS THE TIME OF GREATEST BAROCLINICITY...AND TO LOWER TEMPS
SEVERAL DEGREES SATURDAY AND SUNDAY. IT DOES APPEAR WE WILL SEE
DRYING BY SUNDAY AS THE TROF PUSHES SOUTH OF US...AND CONSENSUS IS
FOR KLONDIKE CHINOOKING BY LATE SUNDAY OR SUNDAY NIGHT.
ACTIVE NORTHERLY FLOW WILL CONTINUE INTO NEXT WEEK AS MORE ENERGY
MOVES INTO OUR AREA BY MONDAY. WILL ADD CLIMO POPS WITH A MODEST
WARMING TREND EARLY NEXT WEEK.
JKL
&&
.AVIATION...
SNOW SHOWERS WILL CONTINUE THIS MORNING ACROSS THE SOUTHERN
PORTIONS OF OUR FORECAST AREA...MAINLY IMPACTING KSHR. THE SNOW
SHOWERS WILL PRODUCE LOCALIZED MVFR TO IFR CONDITIONS BUT WILL
TAPER OFF BY EARLY THIS AFTERNOON. THE MOUNTAINS WILL BE OBSCURED
AT TIMES. OTHERWISE...VFR CONDITIONS WILL PREVAIL TODAY. HOOLEY
&&
.PRELIMINARY POINT TEMP/POPS...
TDY WED THU FRI SAT SUN MON
-------------------------------------------------------
BIL 034 021/048 034/056 033/048 027/034 016/034 021/043
1/E 10/B 01/N 23/O 45/S 21/B 12/W
LVM 039 025/053 036/054 034/045 025/037 015/035 020/043
1/B 00/N 01/N 24/O 45/S 32/S 12/W
HDN 031 018/042 027/053 028/047 025/033 014/033 017/041
2/J 11/E 01/B 23/O 44/S 21/B 12/J
MLS 023 008/030 020/045 025/042 020/027 009/029 017/038
1/N 11/E 11/B 22/S 32/S 21/B 12/J
4BQ 023 010/031 022/048 026/045 022/031 011/030 016/041
2/J 11/E 11/B 22/O 33/S 21/B 12/J
BHK 017 902/024 014/039 024/039 015/022 004/025 013/035
0/N 11/B 12/W 23/S 32/S 11/B 12/J
SHR 028 016/041 025/052 026/043 022/031 011/029 011/040
5/J 20/B 00/B 23/O 45/S 32/S 12/J
&&
.BYZ WATCHES/WARNINGS/ADVISORIES...
MT...NONE.
WY...NONE.
&&
$$
WEATHER.GOV/BILLINGS
AREA FORECAST DISCUSSION...UPDATED
NWS BILLINGS MT
924 AM MST TUE FEB 17 2015
.UPDATE...
SNOW SHOWER ACTIVITY WINDING DOWN OVER SOUTHERN SECTIONS. STILL
LIGHTLY SNOWING AT SHERIDAN WITH STRONGER RETURNS OVER THE
BIGHORNS. WEAK ECHOS EXTEND NORTHWEST TOWARD LEWISTOWN BUT NOTHING
SIGNIFICANT. DECIDED TO DROP NORTHERN BIG HORN AND SOUTHERN
ROSEBUD COUNTIES OUT OF THE ADVISORY AND DROP POPS TO SCATTERED.
WILL KEEP SHERIDAN COUNTY AND THE BIGHORN MOUNTAINS GOING FOR A
COUPLE MORE HOURS. COLD START IN BAKER WITH LOWS FALLING BELOW
ZERO. MAY NOT BE ABLE TO REACH FORECAST HIGH THERE...BUT WITH
SUNSHINE...WILL LET FORECAST RIDE. REST OF THE FORECAST IN GOOD
SHAPE. TWH
&&
.SHORT TERM...VALID FOR TDY AND WED...
SNOW SHOWER ACTIVITY EARLY THIS MORNING WILL GRADUALLY WANE TODAY
AND LEAD TO A DRIER WEATHER PATTERN TONIGHT AND WEDNESDAY.
A NARROW BAND OF RELATIVELY INTENSE SNOW FORMED AFTER MIDNIGHT IN
CENTRAL YELLOWSTONE COUNTY AND WAS CENTERED ACROSS THE BILLINGS
HEIGHTS WHERE SPOTTERS HAVE REPORTED UP TO 3 INCHES OF SNOW AS OF
300 AM MST. THIS BAND FORMED IN UNSTABLE NORTHWEST FLOW ALOFT...
AND WAS ENHANCED IN THE VICINITY OF A WEAK SURFACE WIND SHIFT. IT
WAS VERY NARROW /LESS THAN 5 MILES WIDE/ AND THUS VERY DIFFICULT
TO ANTICIPATE RIGHT UP UNTIL RADAR BEGAN TO SUPPORT ITS FORMATION.
SOME VERY RECENT RADAR TRENDS AS OF 330 AM MST SUGGEST THE BAND
IS WEAKENING...SO ADDITIONAL ACCUMULATION IN THE CITY THROUGH
EARLY THIS MORNING WILL LIKELY BE LESS THAN AN INCH.
OTHERWISE...SNOW SHOWER ACTIVITY IS ALSO CONTINUING OVER FAR SOUTH
CENTRAL MT AND NORTH CENTRAL WY AS OF 330 AM MST...AND OVERNIGHT
MODEL TRENDS SUGGEST IT WILL LINGER THROUGH THE MORNING. HRRR RUNS
EVEN HANG ONTO SNOW IN THE FORT SMITH AND SHERIDAN AREA RIGHT INTO
THE AFTERNOON...THOUGH WITH DECREASING INTENSITY IN TIME. WE THUS
EXTENDED THE WINTER WEATHER ADVISORY FOR BIG HORN...SOUTHERN ROSE-
BUD AND SHERIDAN COUNTIES AND THE NORTHEAST BIGHORN MOUNTAINS OUT
UNTIL NOON MST TODAY. ADDITIONAL ACCUMULATIONS SHOULD ONLY BE ONE
OR TWO INCHES...BUT ROADS WILL REMAIN SLIPPERY AND SNOW COVERED.
BY THIS EVENING...THE AIR MASS WILL BE STABILIZING AS THE HEIGHTS
ALOFT RISE. WE THUS HAVE A DRY FORECAST IN PLAY OVERNIGHT TONIGHT
AND INTO WEDNESDAY...THOUGH AS WARM AIR ADVECTION ALOFT GETS GOING
THERE ARE HINTS IN SOME 00 UTC GUIDANCE FOR VERY LIGHT SNOW ACROSS
SOUTHEASTERN MT TONIGHT INTO WEDNESDAY. FORECAST SOUNDINGS SUGGEST
SATURATION WILL BE LIMITED IN THE NEAR-SURFACE LAYER THOUGH AND SO
WE KEPT WITH THE IDEA OF A DRY FORECAST FOR NOW.
HIGHS TODAY WILL BE COOL...RANGING FROM THE TEENS EAST AND PERHAPS
IN AREAS WHERE SNOW COVER IS GREATEST TO THE 30S F ACROSS SOUTH
CENTRAL MT. WARMING WILL BEGIN IN EARNEST WEDNESDAY ACROSS SOUTH
CENTRAL MT WITH HIGHS IN THE 50S F IN THE FOOTHILLS...BUT MIXING
WILL BE LIMITED FURTHER EAST IN SOUTHEASTERN MT WITH CLOUD COVER
AND LIGHT SOUTHEAST WINDS AHEAD OF A DEVELOPING WARM FRONT. HIGHS
WILL THUS STAY IN THE 20S F WEDNESDAY ACROSS FAR SOUTHEASTERN MT
AND IN FACT OUR FORECAST BE OPTIMISTIC IN SPOTS. SCHULTZ
.LONG TERM...VALID FOR THU...FRI...SAT...SUN...MON...
THURSDAY WILL BE MILD BEHIND A PACIFIC FRONTAL PASSAGE...WITH
FAIRLY STRONG WEST WINDS ALONG OUR FOOTHILLS ESPECIALLY IN THE
MORNING. OUR WEST AND CENTRAL PARTS SHOULD BE WELL-MIXED AND SEE
TEMPS RISE INTO THE 50S...BUT LATEST MODEL RUNS SUGGEST THE SFC
TROF MAY NOT PUSH ALL THE WAY TO THE DAKOTAS...KEEPING PLACES LIKE
BAKER AND EKALAKA COLDER THAN THE REST OF THE CWA. WILL NEED TO
KEEP AN EYE ON THE WINDS AS THE USUAL FOOTHILL LOCATIONS SHOULD
SEE GUSTS TO 50 MPH.
CONFIDENCE CONTINUES TO INCREASE IN A SURGE OF COLD CANADIAN AIR
BY THE END OF THE WEEK. COLD ADVECTION WILL ACTUALLY BEGIN
FRIDAY...IE MAYBE A COMBINATION OF RAIN AND SNOW SHOWERS ON THIS
DAY WITH SHORTWAVE ENERGY FROM THE NW. INTERESTING FACET OF THIS
HIGHLY AMPLIFYING FLOW IS THE POSITIVELY TILTED NATURE OF THE TROF
AS IT PUSHES TOWARD THE NORTHERN GREAT BASIN...WITH STRONG UPPER
RIDGING OFF THE PAC COAST INTO BRITISH COLUMBIA. THIS SHOULD ALLOW
FOR STRONG CANADIAN SFC RIDGING OVER EASTERN MT...WHICH ALL MODELS
SHOW HAPPENING...WITH PRESSURES TO NEAR 1050MB OVER NORTH DAKOTA
BY 12Z SUNDAY PER THE GFS ENSEMBLE MEAN. AS A RESULT WE ARE
LOOKING AT A COUPLE OF FAIRLY COLD DAYS SATURDAY AND SUNDAY.
MODELS STILL DIFFER IN MAGNITUDE OF COLD...SOME SUGGEST 850MB
TEMPS NEAR -20C BY EARLY SUNDAY...WHICH WOULD BE THE COLDEST WE
HAVE SEEN IN QUITE SOME TIME. MAIN FORECAST ADJUSTMENTS WERE TO
RAISE POPS FOR WHAT WILL BE SNOWFALL FRIDAY NIGHT AND SATURDAY...
THIS IS THE TIME OF GREATEST BAROCLINICITY...AND TO LOWER TEMPS
SEVERAL DEGREES SATURDAY AND SUNDAY. IT DOES APPEAR WE WILL SEE
DRYING BY SUNDAY AS THE TROF PUSHES SOUTH OF US...AND CONSENSUS IS
FOR KLONDIKE CHINOOKING BY LATE SUNDAY OR SUNDAY NIGHT.
ACTIVE NORTHERLY FLOW WILL CONTINUE INTO NEXT WEEK AS MORE ENERGY
MOVES INTO OUR AREA BY MONDAY. WILL ADD CLIMO POPS WITH A MODEST
WARMING TREND EARLY NEXT WEEK. JKL
&&
.AVIATION...
SNOW SHOWERS WILL CONTINUE THIS MORNING ACROSS THE SOUTHERN
PORTIONS OF OUR FORECAST AREA...MAINLY IMPACTING KSHR. THE SNOW
SHOWERS WILL PRODUCE LOCALIZED MVFR TO IFR CONDITIONS BUT WILL
TAPER OFF BY EARLY THIS AFTERNOON. THE MOUNTAINS WILL BE OBSCURED
AT TIMES. OTHERWISE...VFR CONDITIONS WILL PREVAIL TODAY. HOOLEY
&&
.PRELIMINARY POINT TEMP/POPS...
TDY WED THU FRI SAT SUN MON
-------------------------------------------------------
BIL 034 021/048 034/056 033/044 025/031 011/029 019/041
3/J 10/B 01/N 23/O 45/S 21/B 12/W
LVM 039 025/053 036/054 034/045 025/034 012/032 018/042
1/B 00/N 01/N 24/O 45/S 32/S 12/W
HDN 031 018/042 027/053 028/045 023/032 010/028 012/039
5/J 11/E 01/B 23/O 44/S 21/B 12/J
MLS 023 008/030 020/045 025/039 017/028 006/028 014/036
1/N 11/E 11/B 22/S 32/S 21/B 12/J
4BQ 023 010/031 022/048 026/042 020/029 008/024 010/037
2/J 11/E 11/B 22/O 33/S 21/B 12/J
BHK 017 902/024 014/039 024/036 012/023 000/020 008/034
1/N 11/B 12/W 23/S 32/S 11/B 12/J
SHR 028 016/041 025/052 026/044 022/032 010/026 009/038
9/J 20/B 00/B 23/O 45/S 32/S 12/J
&&
.BYZ WATCHES/WARNINGS/ADVISORIES...
MT...WINTER WEATHER ADVISORY IN EFFECT UNTIL NOON MST TODAY FOR
ZONE 38.
WY...WINTER WEATHER ADVISORY IN EFFECT UNTIL NOON MST TODAY FOR
ZONES 98-99.
&&
$$
WEATHER.GOV/BILLINGS
AREA FORECAST DISCUSSION
NWS BILLINGS MT
339 AM MST TUE FEB 17 2015
.SHORT TERM...VALID FOR TDY AND WED...
SNOW SHOWER ACTIVITY EARLY THIS MORNING WILL GRADUALLY WANE TODAY
AND LEAD TO A DRIER WEATHER PATTERN TONIGHT AND WEDNESDAY.
A NARROW BAND OF RELATIVELY INTENSE SNOW FORMED AFTER MIDNIGHT IN
CENTRAL YELLOWSTONE COUNTY AND WAS CENTERED ACROSS THE BILLINGS
HEIGHTS WHERE SPOTTERS HAVE REPORTED UP TO 3 INCHES OF SNOW AS OF
300 AM MST. THIS BAND FORMED IN UNSTABLE NORTHWEST FLOW ALOFT...
AND WAS ENHANCED IN THE VICINITY OF A WEAK SURFACE WIND SHIFT. IT
WAS VERY NARROW /LESS THAN 5 MILES WIDE/ AND THUS VERY DIFFICULT
TO ANTICIPATE RIGHT UP UNTIL RADAR BEGAN TO SUPPORT ITS FORMATION.
SOME VERY RECENT RADAR TRENDS AS OF 330 AM MST SUGGEST THE BAND
IS WEAKENING...SO ADDITIONAL ACCUMULATION IN THE CITY THROUGH
EARLY THIS MORNING WILL LIKELY BE LESS THAN AN INCH.
OTHERWISE...SNOW SHOWER ACTIVITY IS ALSO CONTINUING OVER FAR SOUTH
CENTRAL MT AND NORTH CENTRAL WY AS OF 330 AM MST...AND OVERNIGHT
MODEL TRENDS SUGGEST IT WILL LINGER THROUGH THE MORNING. HRRR RUNS
EVEN HANG ONTO SNOW IN THE FORT SMITH AND SHERIDAN AREA RIGHT INTO
THE AFTERNOON...THOUGH WITH DECREASING INTENSITY IN TIME. WE THUS
EXTENDED THE WINTER WEATHER ADVISORY FOR BIG HORN...SOUTHERN ROSE-
BUD AND SHERIDAN COUNTIES AND THE NORTHEAST BIGHORN MOUNTAINS OUT
UNTIL NOON MST TODAY. ADDITIONAL ACCUMULATIONS SHOULD ONLY BE ONE
OR TWO INCHES...BUT ROADS WILL REMAIN SLIPPERY AND SNOW COVERED.
BY THIS EVENING...THE AIR MASS WILL BE STABILIZING AS THE HEIGHTS
ALOFT RISE. WE THUS HAVE A DRY FORECAST IN PLAY OVERNIGHT TONIGHT
AND INTO WEDNESDAY...THOUGH AS WARM AIR ADVECTION ALOFT GETS GOING
THERE ARE HINTS IN SOME 00 UTC GUIDANCE FOR VERY LIGHT SNOW ACROSS
SOUTHEASTERN MT TONIGHT INTO WEDNESDAY. FORECAST SOUNDINGS SUGGEST
SATURATION WILL BE LIMITED IN THE NEAR-SURFACE LAYER THOUGH AND SO
WE KEPT WITH THE IDEA OF A DRY FORECAST FOR NOW.
HIGHS TODAY WILL BE COOL...RANGING FROM THE TEENS EAST AND PERHAPS
IN AREAS WHERE SNOW COVER IS GREATEST TO THE 30S F ACROSS SOUTH
CENTRAL MT. WARMING WILL BEGIN IN EARNEST WEDNESDAY ACROSS SOUTH
CENTRAL MT WITH HIGHS IN THE 50S F IN THE FOOTHILLS...BUT MIXING
WILL BE LIMITED FURTHER EAST IN SOUTHEASTERN MT WITH CLOUD COVER
AND LIGHT SOUTHEAST WINDS AHEAD OF A DEVELOPING WARM FRONT. HIGHS
WILL THUS STAY IN THE 20S F WEDNESDAY ACROSS FAR SOUTHEASTERN MT
AND IN FACT OUR FORECAST BE OPTIMISTIC IN SPOTS. SCHULTZ
.LONG TERM...VALID FOR THU...FRI...SAT...SUN...MON...
THURSDAY WILL BE MILD BEHIND A PACIFIC FRONTAL PASSAGE...WITH
FAIRLY STRONG WEST WINDS ALONG OUR FOOTHILLS ESPECIALLY IN THE
MORNING. OUR WEST AND CENTRAL PARTS SHOULD BE WELL-MIXED AND SEE
TEMPS RISE INTO THE 50S...BUT LATEST MODEL RUNS SUGGEST THE SFC
TROF MAY NOT PUSH ALL THE WAY TO THE DAKOTAS...KEEPING PLACES LIKE
BAKER AND EKALAKA COLDER THAN THE REST OF THE CWA. WILL NEED TO
KEEP AN EYE ON THE WINDS AS THE USUAL FOOTHILL LOCATIONS SHOULD
SEE GUSTS TO 50 MPH.
CONFIDENCE CONTINUES TO INCREASE IN A SURGE OF COLD CANADIAN AIR
BY THE END OF THE WEEK. COLD ADVECTION WILL ACTUALLY BEGIN
FRIDAY...IE MAYBE A COMBINATION OF RAIN AND SNOW SHOWERS ON THIS
DAY WITH SHORTWAVE ENERGY FROM THE NW. INTERESTING FACET OF THIS
HIGHLY AMPLIFYING FLOW IS THE POSITIVELY TILTED NATURE OF THE TROF
AS IT PUSHES TOWARD THE NORTHERN GREAT BASIN...WITH STRONG UPPER
RIDGING OFF THE PAC COAST INTO BRITISH COLUMBIA. THIS SHOULD ALLOW
FOR STRONG CANADIAN SFC RIDGING OVER EASTERN MT...WHICH ALL MODELS
SHOW HAPPENING...WITH PRESSURES TO NEAR 1050MB OVER NORTH DAKOTA
BY 12Z SUNDAY PER THE GFS ENSEMBLE MEAN. AS A RESULT WE ARE
LOOKING AT A COUPLE OF FAIRLY COLD DAYS SATURDAY AND SUNDAY.
MODELS STILL DIFFER IN MAGNITUDE OF COLD...SOME SUGGEST 850MB
TEMPS NEAR -20C BY EARLY SUNDAY...WHICH WOULD BE THE COLDEST WE
HAVE SEEN IN QUITE SOME TIME. MAIN FORECAST ADJUSTMENTS WERE TO
RAISE POPS FOR WHAT WILL BE SNOWFALL FRIDAY NIGHT AND SATURDAY...
THIS IS THE TIME OF GREATEST BAROCLINICITY...AND TO LOWER TEMPS
SEVERAL DEGREES SATURDAY AND SUNDAY. IT DOES APPEAR WE WILL SEE
DRYING BY SUNDAY AS THE TROF PUSHES SOUTH OF US...AND CONSENSUS IS
FOR KLONDIKE CHINOOKING BY LATE SUNDAY OR SUNDAY NIGHT.
ACTIVE NORTHERLY FLOW WILL CONTINUE INTO NEXT WEEK AS MORE ENERGY
MOVES INTO OUR AREA BY MONDAY. WILL ADD CLIMO POPS WITH A MODEST
WARMING TREND EARLY NEXT WEEK.
JKL
&&
.AVIATION...
SNOW SHOWERS WILL CONTINUE THIS MORNING IN CENTRAL PARTS OF OUR
FORECAST AREA...IMPACTING KBIL AND KSHR. THESE SNOW SHOWERS WILL
PRODUCE LOCALIZED MVFR TO IFR CONDITIONS...AND WILL TAPER OFF
GRADUALLY THIS AFTERNOON AND EVENING. LOCAL MVFR CIGS WILL ALSO
IMPACT EASTERN AREAS NEAR KMLS AND KBHK EARLY THIS MORNING. VFR
FLIGHT CONDITIONS WILL BECOME DOMINANT ACROSS THE AREA TONIGHT.
JKL
&&
.PRELIMINARY POINT TEMP/POPS...
TDY WED THU FRI SAT SUN MON
-------------------------------------------------------
BIL 034 021/048 034/056 033/044 025/031 011/029 019/041
3/J 10/B 01/N 23/O 45/S 21/B 12/W
LVM 039 025/053 036/054 034/045 025/034 012/032 018/042
1/B 00/N 01/N 24/O 45/S 32/S 12/W
HDN 031 018/042 027/053 028/045 023/032 010/028 012/039
5/J 11/E 01/B 23/O 44/S 21/B 12/J
MLS 023 008/030 020/045 025/039 017/028 006/028 014/036
1/N 11/E 11/B 22/S 32/S 21/B 12/J
4BQ 023 010/031 022/048 026/042 020/029 008/024 010/037
2/J 11/E 11/B 22/O 33/S 21/B 12/J
BHK 017 902/024 014/039 024/036 012/023 000/020 008/034
1/N 11/B 12/W 23/S 32/S 11/B 12/J
SHR 028 016/041 025/052 026/044 022/032 010/026 009/038
9/J 20/B 00/B 23/O 45/S 32/S 12/J
&&
.BYZ WATCHES/WARNINGS/ADVISORIES...
MT...WINTER WEATHER ADVISORY IN EFFECT UNTIL NOON MST TODAY FOR
ZONES 38-57-58.
WY...WINTER WEATHER ADVISORY IN EFFECT UNTIL NOON MST TODAY FOR
ZONES 98-99.
&&
$$
WEATHER.GOV/BILLINGS
AREA FORECAST DISCUSSION
NWS OMAHA/VALLEY NE
1146 PM CST MON FEB 16 2015
.UPDATE...
ISSUED AT 955 PM CST MON FEB 16 2015
SHORTWAVE IN THE NORTHWEST FLOW ALOFT PRODUCED SOME HALF TO 1.5
INCH AMOUNTS OUT WEST. THIS FEATURE TO DIVE SOUTH OVERNIGHT WITH
REINFORCING COLD AIR AND STRENGTHENING WINDS FOR TUESDAY. WITH
VERY COLD TEMPERATURES...WILL NOT TAKE MUCH TO GET FLURRIES OR
PATCHY LIGHT SNOW. LIGHT SNOW HAS BEEN PATCHY OVER A COUPLE OF
COUNTIES AS IT DROPS SOUTH. FRONTOGENESIS INCREASES AS IT DROPS
SOUTH. THE HI RES MODELS CONFINE THE ACCUMULATING SNOW TO THE
SOUTHWEST PART OF OUR FORECAST AREA AND THE NEW NAM BRUSHES THE
WESTERN COUNTIES AS WELL. WILL MAINTAIN SOME LIGHT ACCUMULATIONS
FOR THE WESTERN/SOUTHWEST AREAS OVERNIGHT. SOME OF THE LIGHT SNOW
AND FLURRIES MAY CONTINUE INTO TUESDAY.
&&
.SHORT TERM...(TONIGHT THROUGH THURSDAY)
ISSUED AT 300 PM CST MON FEB 16 2015
THE PRIMARY FORECAST CONCERN IS POTENTIAL FOR A BAND OF ACCUMULATING
SNOW ACROSS PARTS OF EASTERN NEBRASKA TONIGHT.
UPPER AIR CHARTS FROM 12Z HAD THE FOLLOWING MAIN FEATURES. A STRONG
JETSTREAM WAS NOTED AT 300 MB FROM ALBERTA INTO UTAH...WITH A
COUPLE OF JET SEGMENTS OF OVER 130 KNOTS. A STRONGER JET SEGMENT
OF AROUND 170 KNOTS WAS OVER PENNSYLVANIA. A BROAD AREA OF 12 HOUR
HEIGHT FALLS OF 50 METERS OR MORE AT 500 MB EXTENDED FROM UTAH TO
IOWA AND FROM SOUTH DAKOTA TO TEXAS. A STRONG RIDGE WAS LOCATED
FROM OFF THE CALIFORNIA COAST UP INTO THE YUKON. WINDS WERE
GENERALLY FROM THE NORTHWEST IN THE LOWER AND MIDDLE TROPOSPHERE
FROM OUR AREA NORTHWEST INTO CANADA. PREVIOUSLY MENTIONED 500 MB
RIDGE TO OUR WEST WILL BUILD EAST AND THEN FLATTEN THROUGH
THURSDAY...WHILE A CLOSED LOW FORMS AND DROPS SOUTHEAST ACROSS
ONTARIO AND INTO THE EASTERN GREAT LAKES REGION.
A FAST MOVING SHORTWAVE IN COMBINATION WITH A COMPACT LOW PRESSURE
CENTER SHOULD BRING A BAND OF LIGHT SNOW TO THE REGION TONIGHT.
THE EXACT PLACEMENT OF THIS BAND IS SOMEWHAT UNCERTAIN...BUT THE
LATEST MODEL CONSENSUS (USING A BLEND OF 12Z NAM...18Z NAM...19Z
13 KM RAP ...18Z HRRR AND 15Z SREF MEAN) PLACES THE AXIS FROM
PARTS OF NORTH CENTRAL NEBRASKA INTO NORTHEAST KANSAS. BEST
POTENTIAL IS LIKELY JUST NORTH AND NORTHEAST OF THE TRACK OF THE
SURFACE LOW PRESSURE CENTER. SOUNDINGS...MID LEVEL FRONTOGENESIS
AND IMPRESSIVE 700 MB OMEGA VALUES IN THE DENDRITIC GROWTH ZONE
FROM THE NAM SUGGEST THE ATMOSPHERE MAY PRODUCE SOME AMOUNTS OVER
ONE INCH IN PARTS OF CENTRAL OR SOUTHEAST NEBRASKA DOWN INTO
NORTHEAST KANSAS. BUT WE HAVE MAX AMOUNTS AROUND ONE INCH FOR NOW
AND WILL MENTION THE LOCALIZED POTENTIAL FOR HIGHER AMOUNTS IN THE
HWO. THAT SYSTEM SHOULD PUSH QUICKLY SOUTH OUT OF OUR AREA BY
ABOUT SUNRISE...BUT SOME ISOLATED TO SCATTERED SNOW SHOWERS MAY
OCCUR INTO THE AFTERNOON HOURS. AFTER THAT...SNOW CHANCES SEEM LOW
FROM TUESDAY NIGHT THROUGH WEDNESDAY NIGHT...BUT A SLIGHT CHANCE
OF SNOW WILL RETURN BY THURSDAY.
COLD CANADIAN HIGH PRESSURE WILL BE BUILDING SOUTH FROM ALBERTA
AND SASKATCHEWAN THROUGH WEDNESDAY. WIND CHILLS MAY REACH NEAR
ADVISORY VALUES IN THE NORTH AND NORTHEAST PARTS OF THE FORECAST
AREA LATE TUESDAY NIGHT AND WEDNESDAY MORNING...BUT WILL NOT ISSUE
AN ADVISORY AT THIS POINT. THEN AS THE RIDGE MOVES OFF TO THE
SOUTHEAST AND SOUTHERLY RETURN FLOW DEVELOPS...TEMPERATURES WILL
MODERATE A BIT.
.LONG TERM...(THURSDAY NIGHT THROUGH MONDAY)
ISSUED AT 300 PM CST MON FEB 16 2015
500 MB RIDGE WILL DEVELOP AGAIN FROM THE EASTERN PACIFIC UP INTO
THE YUKON FROM THURSDAY NIGHT INTO SUNDAY. LATEST RUNS OF THE
GFS... ECMWF AND CANADIAN MODELS AGREE ON THE GENERAL LARGE SCALE
FEATURES INTO SUNDAY. DETAILS START TO DIVERGE EARLY NEXT
WEEK...AND CONFIDENCE FALLS TO BELOW NORMAL BY THAT TIME. HAD TO
INCLUDE SOME LOW POPS FOR LIGHT SNOW CHANCES MUCH OF THIS PERIOD.
FRIDAY LOOKS LIKE THE WARMEST DAY...WHEN WE SHOULD SEE HIGHS IN
THE 40S WEST AND 30S EAST. LOWS WILL BE MOSTLY IN THE TEENS...BUT
UPPER TEENS TO MID 20S FOR FRIDAY NIGHT.
&&
.AVIATION...(06Z TAFS FOR KOFK...KLNK AND KOMA.)
ISSUED AT 1135 PM CST MON FEB 16 2015
VFR CONDITIONS INITIALLY...WITH SOME PERIODS OF MVFR CIGS AND
PATCHY LIGHT SNOW THROUGH TUESDAY MORNING AS A WEATHER DISTURBANCE
MOVES THROUGH. SOME ECHOES SHOWING UP ON RADAR AND DID MENTION -SN
AT KLNK TONIGHT. ADDITIONAL LIGHT SNOW/FLURRIES MAY DEVELOP
TUESDAY MORNING. DUE TO UNCERTAINTY OF COVERAGE...FOR NOW JUST
MENTIONED AT KOFK BETWEEN 12-16Z. VARIABLE NORTHWEST WINDS 5 TO
15KT. NORTHWEST WINDS INCREASE TO 10-20KTS WITH GUSTS 25-30KTS
BEGINNING 16-18Z THEN DECREASE TO 10KTS OR LESS AFTER 00Z.
&&
.OAX WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
IA...NONE.
&&
$$
UPDATE...ZAPOTOCNY
SHORT TERM...MILLER
LONG TERM...MILLER
AVIATION...ZAPOTOCNY
AREA FORECAST DISCUSSION
NWS RALEIGH NC
1235 AM EST TUE FEB 16 2015
.SYNOPSIS...A LOW PRESSURE SYSTEM WILL STRENGTHEN OVER THE SOUTHEAST
U.S. OVERNIGHT...AND TRACK NORTHEAST ALONG THE CAROLINA COAST EARLY
TUESDAY MORNING.
&&
.NEAR TERM /THROUGH TUESDAY/...
AS OF 1050 PM MONDAY...
...CONDITIONS DETERIORATING ACROSS CENTRAL NC WITH WIDESPREAD
HAZARDOUS TRAVEL AND NUMEROUS POWER OUTAGES LIKELY...
...WINTER STORM WARNINGS REMAIN IN EFFECT...
HAVE UPGRADED THE FAR SE COUNTIES TO A WARNING AS THE NORTHERN
SECTIONS OF THESE COUNTIES HAVE THE POTENTIAL TO MEET OR EXCEED A
QUARTER OF AN INCH ICE ACCRUAL. TEMPS IN THIS REGION HOLDING IN THE
UPPER 20S AND WILL LIKELY REMAIN AT OR BELOW 30 DEGREES...ESPECIALLY
NORTH OF A CLINTON-FAYETTEVILLE-LAURINBURG LINE.
AREA SOUNDINGS AND LATEST HRRR SOUNDING DATA STILL DEPICT A DECENT
COLD NOSE -8 TO -10 DEGREES C WITH AN EQUALLY IMPRESSIVE WARM NOSE
OF 7 DEGREES C NEAR FAYETTEVILLE. STILL APPEARS THAT BULK OF PRECIP
WILL BE FREEZING RAIN OR A MIXTURE OF SLEET/FREEZING RAIN (DEPENDENT
ON PRECIP INTENSITY). THE LONGER THE PRECIP REMAINS MIXED...THE LESS
ICE ACCRETION WILL OCCUR BUT STILL ENOUGH TO CREATE DANGEROUS ICE
ACCRUAL ON POWERLINES AND TREES. IF PRECIP WERE TO GO MORE TOWARD
ALL SLEET...SLEET ACCUMULATION OF AN INCH OR LITTLE MORE WILL OCCUR
AND ICE ACCRUAL WILL BE SEVERELY LIMITED.
WILL MAINTAIN WARNING ELSEWHERE BUT HAVE LOWERED "MAXIMUM" ICE
ACCRUAL BELOW A HALF INCH. -WSS
820 PM UPDATE...
PRECIP COVERAGE AND INTENSITY WILL BE INCREASING EXPONENTIALLY NEXT
FEW HOURS AS S/W AND ATTENDANT SFC LOW LIFTS E-NE OUT OF THE LOWER
MS VALLEY INTO THE DEEP SOUTH. THE SFC LOW...PER 23Z HRRR
MODEL...STILL PROJECTED TO TRACK IMMEDIATELY SOUTH-SE OF CENTRAL NC
OVERNIGHT.
00Z GSO SOUNDING DEPICTS SOME IMPRESSIVE DATA...ESPECIALLY THE 75KT
JET AT 6K FT. THIS JET PULLING WARMER AIR ALOFT OVER THE
REGION...CAUSING THE PRECIPITATION TYPE TO TRANSITION OVER TO MOSTLY
FREEZING RAIN SOUTH OF HIGHWAY 64...TO A MIXTURE OF SLEET/FREEZING
RAIN ACROSS THE NORTHERN PIEDMONT-NORTHERN/CENTRAL COASTAL PLAIN.
APPEARS MIXTURE SNOW/SLEET STILL FEASIBLE OVER THE FAR NORTHERN
TRIAD AND THE VIRGINIA BORDER COUNTIES THROUGH 10 PM-MIDNIGHT...BUT
EVEN HERE...APPEARS THAT FREEZING RAIN MIXED WITH SLEET WILL BE THE
DOMINATE PRECIP OVERNIGHT.
STILL APPEARS BULK OF PRECIPITATION WILL OCCUR BETWEEN 10 PM - 5
AM....WHEN BEST LIFT OCCURS IN CONJUNCTION WITH A 140KT JET LIFTING
NE ACROSS VA.
HAVE SEVERELY CUTBACK ON SNOW AMOUNTS ACROSS THE NORTHERN PIEDMONT
AND INCREASED ICING POTENTIAL IN VICINITY OF THE TRIAD. THE ICING
NUMBERS IN THE NW PIEDMONT MAY NEED TO BE ADJUSTED UPWARD AS NEW
DATA ARRIVES.
STILL APPEARS THAT A THREAT FOR A DEVASTATING ICE STORM IS A VERY
REAL POSSIBILITY IN A WEST-EAST BAND ACROSS SECTIONS OF PIEDMONT,
SANDHILLS AND COASTAL PLAIN. THIS THREAT APPEARS GREATEST IN
VICINITY OR JUST SOUTH OF HIGHWAY 64. STILL...AMOUNTS WILL BE
DEPENDENT UPON WHETHER PRECIP REMAINED MIXED OR PREDOMINATELY ONE OR
THE OTHER. THE MORE MIXTURE WE RECEIVE...ICE ACCRUAL AMOUNTS WILL BE
A LITTLE LESS. ALSO...IF PRECIPITATION FALLS MODERATE OR
HEAVILY...THIS WOULD LIMIT ICE ACCRUAL AS WELL. NEEDLESS TO
SAY...WITH TEMPERATURES IN THE 20S...ANY TYPE OF PRECIP THAT FALLS
WILL QUICKLY MAKE ROADS SLICK AND BECOMING QUITE
HAZARDOUS.
HAVE ALSO ADJUSTED ICING AMOUNTS IN THE FAR SE AS IT APPEARS ICE
ACCRUAL IN THIS REGION MAY BE A LITTLE LESS AS TEMPS HOVER NEAR OR
JUST BELOW FREEZING...LIMITING ICE ACCRETION.
&&
.SHORT TERM /TUESDAY NIGHT THROUGH FRIDAY/...
AS OF 325 PM MONDAY...
A SHORTWAVE RESULTING FROM A MERGER OF A WAVE CURRENTLY DIVING
THROUGH THE ROCKIES AND THE SHEARING LOW OVER THE CALIFORNIA
BAJA...WILL ROUND THE BASE OF THE FULL-LATITUDE TROUGH AND CROSS THE
SOUTHEAST US TUESDAY NIGHT. DEEP MOISTURE AND THE SYNOPTIC FRONTAL
ZONE WILL BE OFFSHORE BY THEN...SO IT APPEARS THE RESULTING SURFACE
LOW AND PRECIP WILL ALSO BE OFFSHORE AS WELL. LOWS IN THE UPPER
TEENS TO MID 20S.
A SPEED MAX AND ASSOCIATED VORTICITY WILL DIVE THROUGH THE BACK SIDE
OF THE DEEP UPPER TROUGH AND CROSS THE AREA ON WEDNESDAY. FORECAST
SOUNDINGS SHOW SUFFICIENT MOISTURE FOR ICE IN THE -10 TO -20C
LAYER...WHICH ITSELF IS PRETTY LOW IN THIS ARCTIC AIRMASS. Q-VECTOR
CONVERGENCE INCREASE WEDNESDAY AFTERNOON...AND COMBINED WITH STEEP
LOW-LEVEL LAPSE RATES AND SOME WEAK INSTABILITY...SEEMS TO BE ENOUGH
SUPPORT FOR A LOW-END CHANCE OF SNOW SHOWERS AS THE NEXT ARCTIC
FRONT PLOWS THROUGH THE AREA. IF THESE SNOW SHOWERS WERE TO
DEVELOP...THERE COULD BE SOME TRAVEL CONCERNS GIVEN HOW COLD GROUND
TEMPERATURES WILL CONTINUE TO BE. HOWEVER...RATES WOULD NEED TO BE
HIGH AND CONFIDENCE IS VERY LOW AT THIS POINT. HIGHS WEDNESDAY ONLY
INT HE LOW TO MID 30S.
THE STRONG ARCTIC FRONT WILL BE EAST OF THE AREA WEDNESDAY NIGHT AND
THICKNESSES ARE FORECAST TO PLUMMET TO SOMEWHERE IN THE NEIGHBORHOOD
OF 1220M BOTH THURSDAY AND FRIDAY MORNING AS STRONG HIGH PRESSURE
SETTLES OVER HEAD BY FRIDAY. THE GFS IS MUCH COLDER THAN THE ECMWF
WITH 1200M...A VALUE THAT APPEARS TO HAVE BEEN REACH ONLY A COUPLE
TIMES IN THE PAST 50 YEARS. EVEN WITH THE WARMER ECMWF...LOWS WILL
BE IN THE LOW TI MID SINGLE DIGIT RANGE...AND A NEGATIVE TEMP CANT
BE RULED OUT AT THIS POINT. HIGHS THURSDAY LOOK TO ONLY BE IN THE
UPPER TEENS TO MID 20S BASED ON THICKNESS SCHEMES AND DRY ADIABATIC
MIXING. SLIGHTLY WARMER ON FRIDAY IN THE MID 20S TO LOWER 30S.THIS
WILL VERY LIKELY BE RECORD BREAKING COLD THAT WILL WARRANT SOME
PREPARATIONS AND EXTRA PRECAUTIONS.
&&
.LONG TERM /FRIDAY NIGHT THROUGH MONDAY/...
AS OF 325 PM MONDAY...
...RECORD BREAKING AND DANGEROUSLY COLD CONDITIONS FOR THE SECOND
HALF OF THE WEEK...
THE PATTERN SHIFTS A LITTLE OVER THE WEEKEND AS THE UPPER LOW NEAR
THE HUDSON BAY FILLS IN AND THE UPPER LEVEL FLOW OVER THE SOUTHERN
US TURNS TO SOUTHWESTERLY. MODELS ARE SUGGESTIVE OF A SYSTEM
LIFTING FROM THE SOUTHWEST US THROUGH TOWARD THE MIDWEST.
HOWEVER...THE ECWMF AND GFS SHOW MARKEDLY DIFFERENTLY SOLUTIONS.
THE ECMWF SHOWS A STORM TRACK THROUGH THE OHIO VALLEY WHILE THE GFS
LINGERS THE ARCTIC FRONT NEAR OUR LATITUDE AND HAS A COUPLE "OVER-
RUNNING" EVENTS THAT COULD CAUSE SOME WINTRY WEATHER. GIVEN THE
IMPENDING STORM AND UNCERTAINTY...HAVE LEANED ON WPC FOR THIS PERIOD
WITH BASICALLY A CHANCE POPS THROUGH THE LATTER HALF OF THE WEEKEND
AND HIGHS REBOUNDING INTO THE UPPER 30S AND 40S.
&&
.AVIATION /06Z TUESDAY THROUGH SATURDAY/...
AS OF 1235 AM MONDAY...
WIDESPREAD MVFR TO IFR CEILINGS IN A WINTRY MIX WILL CONTINUE ACROSS
THE AREA THROUGH 12 TO 15Z.
PREDOMINATE P-TYPE AT KINT AND KGSO WILL BE SLEET...MIXING WITH A
SOME FREEZING RAIN. KRDU AND KRWI...FREEZING RAIN MIXED WITH SLEET
WILL ALSO BE THE PREDOMINATE P-TYPE. KFAY WILL SEE MOSTLY FZRA.
GRADUAL IMPROVEMENT WILL BEGIN AFTER 15Z TUES... WITH ALL SITES
EXPECTED TO BECOME MVFR AND POSSIBLY VFR TUES AFTERNOON/EVENING.
ANOTHER STRONG ARCTIC COLD FRONT MAY BRING A BRIEF PERIOD OF MVFR
CEILINGS WITH SNOW SHOWERS WEDNESDAY AFTERNOON AND EVENING. HIGH
PRESSURE WILL BRING A HIGH LIKELIHOOD OF VFR CONDITIONS THURSDAY AND
FRIDAY... BEFORE ANOTHER SYSTEM POTENTIALLY IMPACTS THE AREA ON
SATURDAY.
&&
.CLIMATE...
...THE FOLLOWING ARE RECORD LOW AND LOW MAXIMUM TEMPERATURES FOR
FEBRUARY 16TH...19TH...AND 20TH...FOR GSO...RDU...AND FAY...
RECORD LOWS
GSO RDU FAY
FEBRUARY 16: 8 IN 1905 11 IN 1905 17 IN 1991
FEBRUARY 19: 12 IN 1979 11 IN 1979 8 IN 1958
FEBRUARY 20: 14 IN 1934 13 IN 1979 12 IN 1958
RECORD LOW MAXIMUMS
GSO RDU FAY
FEBRUARY 16: 27 IN 1958 30 IN 1943 33 IN 1943
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 STORM WARNING UNTIL NOON EST TUESDAY FOR NCZ011-027-028-042-043-
077-078-085-088-089.
WINTER STORM WARNING UNTIL 9 AM EST TUESDAY FOR NCZ007>010-021>026-
038>041-073>076-083-084.
&&
$$
SYNOPSIS...WSS
NEAR TERM...WSS
SHORT TERM...BLS
LONG TERM...BLS
AVIATION...CBL
CLIMATE...RAH
AREA FORECAST DISCUSSION
NWS NORMAN OK
1226 PM CST TUE FEB 17 2015
.UPDATE...
RADAR IS SHOWING PRECIPITATION DEVELOPING ACROSS THE NORTHERN
TEXAS PANHANDLE... ALTHOUGH SOME OF THIS MAY BE VIRGA AT THIS
TIME. BUT GIVEN THIS INCREASE IN COVERAGE AND THE HRRR AND RAP
BOTH SHOWING SOME FORECAST REFLECTIVITY AND QPF MOVING ACROSS THE
AREA THIS AFTERNOON. THEREFORE WE HAVE EXPANDED THE POPS /ALBEIT
LOW POPS/ ACROSS ALMOST ALL OF THE AREA.
&&
.PREV DISCUSSION... /ISSUED 523 AM CST TUE FEB 17 2015/
DISCUSSION...
THE 12Z AVIATION DISCUSSION FOLLOWS....
AVIATION...
A COLD FRONT WILL BRING A WIND SHIFT AND INCREASING WINDS TO THE
REGION TODAY...WHILE AN ASSOCIATED UPPER-LEVEL DISTURBANCE WILL
GENERATE A FEW SHRA AT TIMES. THE SHRA WILL BE TOO MINOR IN
IMPACT...AND TOO FEW IN NUMBER...TO WARRANT ANY MENTION IN THE
TAFS. WINDS WILL DECREASE AND BECOME MORE VARIABLE IN DIRECTION
AFTER SUNSET.
PREV DISCUSSION... /ISSUED 433 AM CST TUE FEB 17 2015/
DISCUSSION...
A FEW SHOWERS MAY OCCUR TODAY AS WEAK DISTURBANCES CIRCULATE
THROUGH A LARGE UPPER-LEVEL TROUGH. TEMPERATURES WILL RISE TO NEAR
THE AVERAGE FOR THIS TIME OF YEAR TODAY...BUT A SLIGHT
REINFORCEMENT OF THE COLDER AIR WILL MAKE TOMORROW A BIT COLDER.
A SURFACE LOW WILL DEVELOP OVER WEST TEXAS THURSDAY AND THURSDAY
NIGHT...AND CIRCULATION AROUND THIS FEATURE WILL BRING A SURGE OF
WARMER AND MUCH MORE HUMID AIR INTO OUR SOUTHERN COUNTIES.
THIS WARMER AND MORE HUMID AIR WILL CONTINUE ITS NORTHWARD
ADVANCE ON FRIDAY...LEADING TO A CLOUDY...HUMID DAY ACROSS MOST OF
OKLAHOMA AND NORTH TEXAS. A FEW SHOWERS AND THUNDERSTORMS WILL BE
POSSIBLE FRIDAY AND FRIDAY NIGHT AS THE OVERALL STORM SYSTEM
BEGINS TO SHIFT EAST.
A STRONG COLD FRONT WILL ADVANCE SOUTHEAST ACROSS OKLAHOMA AND
NORTH TEXAS SATURDAY AND SATURDAY NIGHT. THIS WILL BRING MUCH
COOLER AIR INTO THE REGION. RAIN CHANCES WILL CHANGE TO SNOW
CHANCES IN THE NORTH INITIALLY...AND THE RAIN/SNOW LINE WILL SHIFT
BACK AND FORTH ACROSS THE REGION UNTIL MONDAY NIGHT...WHEN
RAIN/SNOW CHANCES FINALLY END. AT THIS TIME...IT DOES NOT APPEAR
THAT WE WILL SEE ORGANIZED AREAS OF SNOWFALL...SO ACCUMULATIONS
SHOULD BE LIGHT WHERE THEY OCCUR AT ALL.
&&
.PRELIMINARY POINT TEMPS/POPS...
OKLAHOMA CITY OK 51 25 44 23 / 20 0 0 0
HOBART OK 52 25 49 26 / 20 0 0 0
WICHITA FALLS TX 55 29 54 29 / 20 0 0 0
GAGE OK 49 20 48 24 / 20 0 0 0
PONCA CITY OK 47 20 37 17 / 20 10 0 0
DURANT OK 51 30 50 25 / 20 10 0 0
&&
.OUN WATCHES/WARNINGS/ADVISORIES...
OK...NONE.
TX...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS PORTLAND
206 PM PST TUE FEB 17 2015
.SYNOPSIS...A STRONG RIDGE OF HIGH PRES OVER THE REGION WILL WEAKEN
SOME...ALLOWING A COUPLE OF WEAK SYSTEMS TO MOVE ACROSS THE PACIFIC
NW IN THE MIDDLE AND LATTER PART OF THE WEEK. OFFSHORE FLOW WILL
REDEVELOP OVER THE WEEKEND AGAIN AS THE RIDGE REBUILDS.
&&
.SHORT TERM...CURRENT THROUGH FRIDAY...VISIBLE SATELLITE IMAGERY
THIS AFTERNOON SHOWS JUST A COUPLE OF CIRRUS CLOUDS ACROSS THE
FORECAST AREA AND WE WILL CONTINUE TO EXPERIENCE ANOTHER WARM AND
SUNNY DAY. THIS PATTERN WILL SHIFT SLIGHTLY OVER THE NEXT 24 HOURS
AS HIGH PRESSURE BEGINS TO WEAKEN AND SOUTHERLY FLOW MOVES UP THE
COAST AND THEN INLAND. THE S/SW FLOW IS VERY APPARENT ON SATELLITE
TODAY DUE TO AN ASSOCIATED LOW STRATUS PUSH WHICH HAS MADE IT AS FAR
NORTH AS ABOUT TILLAMOOK OFFSHORE AND IS BEGINNING TO AFFECT THE
DOUGLAS COUNTY COAST ON LAND. THIS PUSH WILL CONTINUE NORTHWARD WITH
THE COAST ENGULFED IN CLOUDS BY WEDNESDAY MORNING AND MOSTLY CLOUDY
SKIES PUSHING INLAND DURING THE DAY WEDNESDAY. THE RAP APPEARS TO BE
DOING THE BEST JOB WITH TIMING AT THIS POINT.
THE FIRST OF A NUMBER OF WEAK SHORTWAVES MOVES THROUGH THE AREA
WEDNESDAY AND MAY HELP TO SQUEEZE OUT SOME DRIZZLE ALONG THE COAST.
WED NIGHT INTO THU MODELS INDICATE RIDGE BEGINNING TO REBUILD
OFFSHORE...WITH A MORE NORTHERLY TRACK FOR SHORTWAVES TO DROP
THROUGH THE REGION. MOISTURE AT THIS POINT REMAINS PRIMARILY IN THE
LOW LEVELS...BELOW ABOUT 6K FT...BUT THE TRACK OF THE SHORTWAVES
ALONG WITH BEST ONSHORE FLOW IN THE N INDICATE A CHANCE FOR SHOWERS
TO REMAIN ACROSS THE N PART OF THE FORECAST AREA. MODELS DIVERGE
SLIGHTLY FRIDAY REGARDING THE POSITION OF ONE LAST SHORTWAVE. THE
GFS BRINGS THE SHORTWAVE RIGHT OVER THE FORECAST AREA AND CALLS FOR
CONTINUING POPS THROUGH FRIDAY WHILE THE ECMWF PUSHES IT INTO
EASTERN OREGON AND SHOWS A DRY SOLUTION FRIDAY WEST OF THE CASCADES.
HAVE TRENDED TOWARD THE DRIER ECMWF AND LEFT OUT MENTIONABLE POPS
FRIDAY FOR THE TIME BEING. BOWEN
.LONG TERM...DRY NORTHERLY FLOW WILL MAINTAIN SUNNY AND SEASONAL
TEMPERATURES THIS WEEKEND. SATURDAY...FLOW ALOFT TURNS MORE
NORTHEASTERLY...WHICH WILL KEEP TEMPERATURES ON THE COOLER SIDE AS
WELL AS THE POSSIBILITY FOR BREEZY EAST WINDS THROUGH THE COLUMBIA
GORGE. HIGH PRESSURE SHIFTS INLAND...ALLOWING TEMPERATURES TO WARM
UP AGAIN INTO THE LOWER 60S SUNDAY INTO EARLY NEXT WEEK. MODELS ARE
REALLY TRYING TO BRING IN SOME PRECIPITATION...AND POSSIBLY SNOW TO
THE CASCADES BY MIDDLE OF NEXT WEEK...BUT DON`T HOLD YOUR BREATH
GIVEN THE EXTREMELY DRY ENVIRONMENT IN PLACE BY THAT TIME. /27
&&
.AVIATION...VFR INLAND THROUGH AT LEAST MOST OF THE EVENING. A
SOUTHERLY STRATUS/FIG SURGE IS NEARING NEWPORT WITH LIFR CIGS
EXPECTED TO ARRIVE AROUND THE 23Z TIME FRAME. MODEL DATA INDICATES THE
MARINE FRONT WILL BE DEEP ENOUGH TO SPILL OVER INTO THE WILLAMETTE
VALLEY AND BRING A SOUTHWESTERLY BURST OF WIND AND EVENTUALLY AN
IFR DECK TO KEUG BY LATER THIS EVENING. WILL SEE THE COASTAL DECK
CONTINUE TO PUSH NORTH AND REACH KAST CLOSER TO 05Z. HAVE HIGH
CONFIDENCE THE STRATUS WILL IMPACT KONP AND KAST BUT HAVE LESS
CONFIDENCE WITH REGARD TO THE SPECIFIC TIMING. AS THE OFFSHORE
SURFACE MOVES NORTH...WILL EVENTUALLY SEE THE WINDS SHIFT ONSHORE
OVERNIGHT AND BRING MOIST MARINE AIR TO THE INLAND TERMINALS. BOTH
NAM AND GFS TIME HEIGHT FORECASTS SHOW A 3000 FT CIG DEVELOPING AT
KHIO...KPDX...AND KTTD AROUND DAYBREAK. WILL PROBABLY NOT SEE
MUCH CHANGE ANYWHERE THROUGHOUT THE REST OF THE DAY AS AN OFFSHORE
COLD FRONT NEARS TOWARD THE AFTERNOON.
KPDX AND APPROACHES...VFR CONDITIONS UNDER EAST WINDS WILL
CONTINUE THROUGH THIS EVENING. WINDS WILL BEGIN TO SLACK OFF THIS
AFTERNOON AS THE SURFACE GRADIENT WEAKENS THEN TURN ONSHORE THIS
EVENING. THE ONSHORE WINDS WILL BRING COOL MOIST MARINE AIR ALONG
WITH CIGS AROUND 030 NEAR DAYBREAK. EXPECT LITTLE CHANGE ON
WEDNESDAY THEREAFTER. JBONK
&&
.MARINE...SURFACE LOW PRESSURE BRINGING SOUTHERLY STRATUS/FOG
SURGE UP THE COAST. CENTRAL WATERS ARE NEARLY COVERED AT THIS TIME
AND EXPECT THE NORTHERN WATERS WILL BE IN SIMILAR SHAPE BY MID
EVENING. SMALL CRAFT ADVISORY GUSTS WILL TRAIL THE LEADING EDGE OF
THE MARINE FRONT THIS EVENING AND INTO WEDNESDAY MORNING ALONG
WITH SOUTHERLY PRE FRONTAL WINDS AHEAD OF A WEAKENING COLD FRONT
WEDNESDAY EVENING. HIGH PRESSURE REBUILDS ALOFT AND AT THE SURFACE
THEREAFTER.A SURFACE THERMAL LOW DEVELOPS OVER SW OREGON AND NRN
CALIFORNIA TO BRING SUMMERTIME PATTERN OF GUSTY NORTH WINDS NEARER
SHORE AND MARGINALLY FLIRTING WITH SMALL CRAFT GUST CRITERIA OF 21
KT AT TIMES. SEAS ACROSS ALL WATERS APPEAR TO REMAIN 4 TO 7 FT FOR
THE BULK OF THE WEEK AHEAD BECOMING WIND WAVE DOMINATED AT TIMES.
/JBONK
&&
.PQR WATCHES/WARNINGS/ADVISORIES...
OR...NONE.
WA...NONE.
PZ...SMALL CRAFT ADVISORY FOR WINDS FROM 9 PM THIS EVENING TO 9 AM
PST WEDNESDAY FOR WATERS FROM CAPE SHOALWATER WA TO CASCADE
HEAD OR FROM 10 TO 60 NM-WATERS FROM CASCADE HEAD TO
FLORENCE OR FROM 10 TO 60 NM.
&&
$$
INTERACT WITH US VIA SOCIAL MEDIA
WWW.FACEBOOK.COM/NWSPORTLAND
WWW.TWITTER.COM/NWSPORTLAND
THIS DISCUSSION IS FOR NORTHWEST OREGON AND SOUTHWEST WASHINGTON
FROM THE CASCADE CREST TO 60 NAUTICAL MILES OFFSHORE. THE AREA IS
COMMONLY REFERRED TO AS THE FORECAST AREA.
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
651 PM EST WED FEB 18 2015
.SYNOPSIS...
AN ARCTIC FRONT AND POTENT UPPER LEVEL DISTURBANCE WILL BRING
SNOW SHOWERS OR EVEN A FEW HOUR PERIOD OF STEADIER SNOW TO THE
THIS AFTERNOON AND TONIGHT...WITH THE POTENTIAL FOR AN EXTENSIVE
NORTH- SOUTH BAND OF INTENSE...DANGEROUS SNOW SQUALLS MARCHING
ACROSS CENTRAL PENNSYLVANIA AND THE SUSQUEHANNA VALLEY THROUGH THE
LATE AFTERNOON AND EARLY EVENING. BITTER COLD TEMPERATURES AND
SUBZERO WIND CHILLS ARE EXPECTED TONIGHT...THROUGH THURSDAY AND INTO
FRIDAY MORNING.
A GRADUAL WARM-UP WILL OCCUR THIS COMING WEEKEND...BUT WITH IT
WILL COME A BOUT OF WINTRY WEATHER AS LOW PRESSURE ORGANIZES AND
MOVES NORTHEAST FROM THE MID MISSISSIPPI VALLEY TO THE EASTERN
GREAT LAKES REGION.
&&
.NEAR TERM /UNTIL 10 PM THIS EVENING/...
SECOND MAJOR SNOW SQUALL EVENT SINCE SATURDAY HIT CENTRAL PA HARD
THIS AFTERNOON AND EVENING WITH WHITEOUT CONDITIONS AND WIDESPREAD
1-2" ACCUMS. SUSQUEHANNA RIVER VALLEY AND ENDLESS MOUNTAIN REGIONS
ARE UNDER THE GUN NOW. FARTHER WEST...ARCTIC AIR IS NOW POURING
BACK INTO THE REGION...WITH TEMPS PLUMMETING THROUGH THE TEENS.
FAR WESTERN AND NORTHWEST PA IS NOW DROPPING BELOW 10F.
FOLLOWING THIS FRONT...MID AND UPPER FLOW WILL BE NEARLY PARALLEL
SUPPORTING ANAFRONT-LIKE PRECIP IN THE FORM OF A FEW TO SVRL HOUR
PERIOD OF LIGHT TO MDT SNOW -MAINLY ACROSS THE NW HALF OF THE
STATE.
MOST PLACES ACROSS CENTRAL PENN SHOULD SEE 1-2 INCHES TOTAL
THROUGH THURSDAY...WITH THE MTNS OF NRN PENN PICKING UP 2-3
INCHES AND THE LAURELS SEE AS MUCH AS 3-5 INCHES BY EARLY THURSDAY
MORNING. A WINTER WEATHER ADVISORY CONTINUES FOR THE LAURELS TO
MIDNIGHT TONIGHT. WIND CHILL HEADLINES CONTINUE.
&&
.SHORT TERM /10 PM THIS EVENING THROUGH 6 PM THURSDAY/...
WIND CHILL WARNINGS TONIGHT...BEGINNING AT MIDNIGHT FOR ALL OF
THE WESTERN AND NRN MTNS...WHILE WIND CHILL ADVISORIES WERE ISSUED
ELSEWHERE. THESE WIND CHILL PRODUCTS CONTINUE RIGHT THROUGH 15Z
FRIDAY AS THE COLD AIR MASS WILL MOVE OVER AND SIT OVER THE REGION
THROUGH FRIDAY.
LOWS TONIGHT BE AROUND -5 TO -10F ACROSS THE NW MTNS...TO THE
SINGLE DIGITS ABOVE ZERO THROUGH CENTRAL PA...TO NEAR 10F IN THE
SE.
HIGHS THURSDAY WILL STRUGGLE TO CLIMB ABOVE ZERO IN THE NW MTNS
/AND STAY JUST IN THE SINGLE DIGITS TO TEENS ELSEWHERE/ WITH
CONTINUED GUSTY NW WINDS UP TO 30-35 MPH AND OCNL FLURRIES AND
BANDS OF SNOW SHOWERS. THE SNOW SHOWERS COULD ADD ANOTHER COATING
TO 1/2 INCH IN THE CENTRAL RIDGE AND VALLEY REGION...AND ANOTHER
INCH POSSIBLE IN THE ALLEGHANIES.
&&
.LONG TERM /THURSDAY NIGHT THROUGH WEDNESDAY/...
AXIS OF LONGITUDINALLY BROAD UPPER TROF COVERING THE CONUS EAST
OF THE ROCKIES AT THE START OF THE LONG TERM PERIOD IS FORECAST
TO SHIFT EAST AND TRANSITION THE UPPER FLOW TO A ZONAL PATTERN BY
THE WEEKEND. CORE OF ARCTIC AIR ALOFT IS FORECAST TO DROP INTO NRN
PA THURSDAY AFTN/EVE...SUPPORTING THE SHIFT IN THE UPPER FLOW. IN
RESPONSE TO ADDITIONAL COLD AIR/ENERGY DROPPING SOUTH ALONG THE
FRONT RANGE OVER THE WEEKEND...THE UPPER FLOW OVER THE EAST IS
FORECAST TO TURN SWRLY INTO NEXT WEEK. AS A RESULT...VERY COLD
AIR WILL CONTINUE TO IMPACT THE REGION THROUGH AT LEAST THE REST
OF THE WORK-WEEK.
THE FLATTENING OF THE UPPER FLOW OVER THE NORTHEAST THIS COMING
WEEKEND WILL LEAD TO A MODERATION AWAY FROM THE BITTER COLD WE
HAVE EXPERIENCED IN THE CURRENT PATTERN.
THE CENTER OF THIS NEXT ARCTIC HIGH MAY SLIDE JUST SOUTH OF THE
REGION THEN OFF THE MID ATLANTIC COAST - PER THE 00Z EC...WHILE
THE GEFS WOULD SUGGEST A LITTLE MORE IN THE WAY OF LLVL COLD AIR
DAMMING OVER THE CWA...PRECEDING INCREASING MOISTURE AND A WINTRY
MIX OR SNOW SPREADING IN FROM THE SW...THEN ANOTHER PUSH OF
ARCTIC AIR FOR LATE SUNDAY AND MONDAY.
TEMPERATURES SUNDAY LOOK TO RISE WELL ABOVE THE FREEZING MARK
OVER A GOOD PART OF CENTRAL PA AS THE EARLIER MENTIONED MODERATION
IN THE UPPER FLOW IS FORECAST TO ARRIVE. THE NEXT SHORTWAVE
TROF/SFC FRONT IS ALSO CURRENTLY TIMED TO MOVE FROM THE MID MISS
VALLEY TO ERN GLAKES REGION THIS SATURDAY AND SUNDAY... LEADING TO
THE POSSIBILITY OF SNOW OR RAIN FOR A CHANGE OVER SRN PA AND SNOW
OVER THEN NORTH. LATEST RUNS OF MDM RANGE GUIDANCE NOW DEVELOPS A
SFC LOW ALONG THE FRONT...POSSIBLY MOVING ACROSS PA. HAVE
INCREASED POPS...QPF AND POTENTIAL FOR A MESSY WINTER WEATHER
EVENT MAINLY DURING THE DAY SUNDAY.
AS HIGH PRESSURE MOVES ACROSS THE REGION NEXT MONDAY AND TUESDAY
BEHIND SUNDAY`S POTENTIAL SYSTEM...DRY WEATHER IS EXPECTED WITH
TEMPS AGAIN RETURNING BELOW NORMAL...BUT NOT AS FAR BELOW AS IN
RECENT DAYS. SCATTERED SNOW SHOWERS WILL TAPER OFF THROUGH EARLY
TUESDAY...THEN INCREASE OVER THE MTNS WEDNESDAY AS ANOTHER PUSH OF
ARCTIC AIR ARRIVES A SHORTWAVE ON WED.
&&
.AVIATION /00Z THURSDAY THROUGH MONDAY/...
IFR AND LOWER CIGS AND VSBYS FROM FROM THE BEFORE MENTIONED TROUGH
AND ASSOCIATED SNOW SQUALLS AND SHOWERS WILL CONTINUE THROUGH 00Z. SHSN
SHOULD EVENTUALLY REACH INTO THE ERN AIRFIELDS WITH MVFR/IFR
RESTRICTIONS EXPECTED BETWEEN 21Z TO 00Z. INTENSE SNOW SQUALLS
WILL ACCOMPANY THE ARCTIC FROPA AND IS RESULTING IN RAPID DROP IN
VISBYS AOB 1/2SM. HAVE INCLUDED 1HR TEMPO OF 1/4 TO 1/2SM VISBYS
BASED ON THE LATEST HRRR AND NAM. SFC WINDS INITIALLY FROM
200-230 DEGREES WILL SHIFT TO 270-300 BEHIND THE FRONT WITH GUSTS
15-25MPH. PROLONGED IFR EXPECTED AT BFD/JST WITH COLD NW UPSLOPE
FLOW SHSN CONTINUING TONIGHT.
CONDITIONS WILL SLOWLY IMPROVE LATE TONIGHT INTO TOMORROW
MORNING...WITH VSBYS LIFTING BETWEEN 02Z TO 06Z...AT ALL TAF
SITES AND CIGS SLOWLY LIFTING TOWARDS MORNING.
OUTLOOK...
THU...MVFR/IFR -SHSN WRN 1/3. MAINLY VFR CENTRAL AND ERN TAFS.
FRI...BCMG VFR. NO SIG WX.
SAT-SUN...MVFR/IFR LKLY WITH MIXED PCPN.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
WIND CHILL WARNING FROM MIDNIGHT TONIGHT TO 10 AM EST FRIDAY
FOR PAZ004>006-010>012-017-018-024-033-037-041-042.
WIND CHILL ADVISORY FROM MIDNIGHT TONIGHT TO 10 AM EST FRIDAY
FOR PAZ019-025>028-034>036-045-046-049>053-056>059-063>066.
WINTER WEATHER ADVISORY UNTIL NOON EST THURSDAY FOR PAZ024-033.
&&
$$
SYNOPSIS...LAMBERT
NEAR TERM...DEVOIR/LAMBERT/CERU
SHORT TERM...LAMBERT
LONG TERM...LAMBERT/GARTNER
AVIATION...CERU/STEINBUGL
PLEASE SEE THE 18Z AVIATION FORECAST DISCUSSION BELOW.
&&
.AVIATION...
CLOUD COVER WILL GRADUALLY DECREASE ACROSS SOUTH CENTRAL TEXAS
THROUGH THE REMAINDER OF THIS AFTERNOON AND EARLY EVENING. BKN-OVC
CLOUD BASES AROUND 6K AGL WILL BECOME SCT BY LATE AFTERNOON AS
NORTHERLY WINDS DECREASE. SKIES SHOULD REMAIN CLEAR OVERNIGHT AS
WINDS BECOME LIGHT AND VARIABLE. FOR TOMORROW MORNING...LIGHT
SOUTHWEST TO WEST WINDS DEVELOP ALONG THE I-35 CORRIDOR...WHILE
LIGHT SOUTHEASTERLY WINDS DEVELOP AT KDRT.
&&
.PREV DISCUSSION... /ISSUED 935 AM CST TUE FEB 17 2015/
UPDATE...
ONLY RETURNS LEFT ON RADAR AT 930AM WERE LOCATED OVER
KARNES...DEWITT...AND LAVACA COUNTIES AND ON ITS WAY OUT. FOR THE
REST OF THE DAY...NOT EXPECTING ANY OTHER PRECIP AND CLOUDS WILL
BE ON THE DECREASE.
PERFORMED THE TYPICAL OBS BLEND INTO FORECAST HOURLIES AS WELL AS
REMOVING POPS FROM THE GRIDS FOR THE REMAINDER OF THE MORNING.
TB3
PREV DISCUSSION... /ISSUED 330 AM CST TUE FEB 17 2015/
SHORT TERM (TODAY THROUGH WEDNESDAY)...FINAL PIECE OF MID LEVEL
FORCING IN THE BASE OF THE TROUGH WILL ROTATE THROUGH THE CWA THIS
MORNING. HAVE FOLLOWED SLIGHTLY CLOSER TO THE HRRR THROUGH MIDDAY
GIVEN THE BETTER HANDLING OF WHERE PRECIP IS CURRENTLY FALLING
ACROSS SOUTHERN AREAS OF SJT AND MAF CWAS. THAT SAID...THERE IS A
SIGNIFICANT DRY LAYER BELOW 800MB ACROSS NORTHERN AND EASTERN
AREAS OF THE CWA...WHICH MAY PREVENT MUCH OF THE PRECIP FROM REACHING
THE GROUND (ESPECIALLY NORTH OF A LLANO TO AUSTIN TO SCHULLENBURG
LINE). WHERE PRECIP DOES REACH THE GROUND...COLUMN WILL BE COOL
ENOUGH ALONG AND WEST OF I-35 FOR LIGHT SLEET OR SNOW FLURRIES TO
MIX IN...ESPECIALLY ACROSS CENTRAL AND WESTERN HILL COUNTRY. THERE
WAS SOME -SN REPORTED EARLIER IN OZONA. GROUND TEMPERATURES FOR
MOST LOCATIONS WILL REMAIN ABOVE FREEZING AND THEREFORE GENERALLY
NO ACCUMULATION IS EXPECTED. HOWEVER...CAN NOT RULE OUT SOME VERY
PATCHY...ELEVATED SURFACES ACROSS THE NORTHERN HILL COUNTRY SEEING
SOME VERY LIGHT ACCUMULATIONS. OVERALL...NOT ENOUGH TO WARRANT AN
ADVISORY...BUT WILL ISSUE AN SPS.
CLEARING WILL TAKE PLACE WEST TO EAST THIS AFTERNOON AND EVENING.
CLEAR SKIES AND LIGHT WINDS...WITH LOW LEVEL RIDGE AXIS OVER THE
CWA...WILL LEAD TO A COLD NIGHT. LOWS WEDNESDAY MORNING DIP INTO
THE MID AND UPPER 20S ACROSS THE HILL COUNTRY AND LOW TO MID 30S
ELSEWHERE. HIGHS REBOUND INTO THE MID 60S UNDER SUNNY SKIES
WEDNESDAY.
JR
LONG TERM (WEDNESDAY NIGHT THROUGH MONDAY)...A WARMING TREND WILL
OCCUR THURSDAY THROUGH SATURDAY ACROSS THE CWA...WITH TEMPERATURES
BACK ABOVE NORMAL FRIDAY AND SATURDAY. LOW LEVEL RETURN FLOW WILL
DEVELOP OVER THE AREA ON THURSDAY...WITH A RETURN OF CLOUDS
THURSDAY NIGHT. PATCHY DRIZZLE AND ISOLATED SHOWERS POSSIBLE
MAINLY ALONG AND EAST OF I-35 FRIDAY AND SATURDAY. ECMWF AND GFS
IN GENERAL AGREEMENT WITH THE NEXT COLD FRONT MOVING THROUGH
SOUTH-CENTRAL TEXAS SUNDAY MORNING. ISENTROPIC UPGLIDE PATTERN
DEVELOPS OVER THE SHALLOW...COLD AIRMASS LEADING TO CLOUDY AND MUCH
COLDER CONDITIONS SUNDAY AND MONDAY ALONG WITH CHANCES FOR RAIN.
&&
.PRELIMINARY POINT TEMPS/POPS...
AUSTIN CAMP MABRY 51 35 65 40 71 / 20 0 0 0 0
AUSTIN BERGSTROM INTL AIRPORT 49 29 64 35 69 / 20 0 0 0 0
NEW BRAUNFELS MUNI AIRPORT 50 32 66 38 72 / 20 0 0 0 0
BURNET MUNI AIRPORT 49 32 62 37 68 / 20 0 0 0 0
DEL RIO INTL AIRPORT 53 35 67 43 72 / 20 0 0 0 0
GEORGETOWN MUNI AIRPORT 51 31 64 37 68 / 20 0 0 0 0
HONDO MUNI AIRPORT 53 30 65 37 73 / 30 0 0 0 0
SAN MARCOS MUNI AIRPORT 51 31 65 37 71 / 20 0 0 0 0
LA GRANGE - FAYETTE REGIONAL 51 33 65 38 71 / 20 0 0 0 0
SAN ANTONIO INTL AIRPORT 52 33 65 40 71 / 30 0 0 0 0
STINSON MUNI AIRPORT 53 33 65 39 72 / 30 0 0 0 0
&&
.EWX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
MESOSCALE/AVIATION...24
SYNOPTIC/GRIDS...03
PUBLIC SERVICE/DATA COLLECTION...33
AREA FORECAST DISCUSSION...UPDATED
NWS LUBBOCK TX
1135 AM CST TUE FEB 17 2015
.AVIATION...
CEILINGS WILL REMAIN MOSTLY VFR AT THE TAF SITES WITH BRIEF
PERIODS OF MVFR CONTINUING AT KCDS AND KPVW. EXPECT CEILINGS TO
GRADUALLY INCREASE INTO THE VFR RANGE BY LATE THIS AFTERNOON AND
SHOULD SEE VFR CONDITIONS CONTINUE THROUGH THE OVERNIGHT HOURS
INTO WEDNESDAY.
&&
.PREV DISCUSSION... /ISSUED 626 AM CST TUE FEB 17 2015/
UPDATE...
DWINDLING SNOW ON RADAR THOUGH WITH LIGHT BANDS STILL TO FOLLOW
SEEMS IN LINE WITH LATEST RAP RUN. ALLOWED WINTER WEATHER ADVISORY
TO EXPIRE SOUTHWESTERN SOUTH PLAINS...DO NOT ANTICIPATE MORE THAN
A DUSTING REMAINDER OF THE AREA WITH SNOW MOSTLY ENDING BY 15Z.
RMCQUEEN
PREV DISCUSSION... /ISSUED 537 AM CST TUE FEB 17 2015/
AVIATION...
LIGHT SNOW WILL DWINDLE OVER THE NEXT COUPLE HOURS ACROSS THE SOUTHERN
SOUTH PLAINS INCLUDING KLBB WITH MVFR DOMINATING THROUGH 13Z OR 14Z.
BOTH KPVW AND KCDS APPEAR TOO DISTANT FROM THE BULK OF LIFT AND
DEEPER MOISTURE TO MENTION LINGERING SNOW CHANCES. DOWNSLOPE DRYING
WILL INCREASE MID TO LATE MORNING THOUGH STILL JUST ENOUGH MOISTURE
PERHAPS FOR A CUMULUS FIELD CONNECTED WITH MID LEVEL COOL POCKET
PASSING OVERHEAD. DRY AND VFR OVERNIGHT. RMCQUEEN
PREV DISCUSSION... /ISSUED 320 AM CST TUE FEB 17 2015/
SHORT TERM...
UPPER LEVEL IMPULSE TRANSLATING THROUGH THE AREA THIS MORNING RIGHT
ON SCHEDULE...AND DIRECTED MORE TOWARDS SOUTHERN ZONES WITH LIFT AND
SLIGHTLY DEEPER MOISTURE. THE MID LEVEL LIFT OVERNIGHT SO FAR HAS
SUCCEEDED IN MODEST TOP-DOWN MOISTENING AND SURFACE DEW-POINTS LATELY
HAVE RISEN OVER SOUTHERN ZONES AT LEAST TO THE POINT WHERE LIGHT
SNOW OR SNOW SHOWERS COULD REACH THE GROUND OVER A LARGER AREA. WITH
THAT...HOWEVER...THE RECENT RAP TRENDS SUPPORT ONLY A BRIEF
OPPORTUNITY FOR MOSTLY INSIGNIFICANT ACCUMULATIONS ACROSS MAINLY THE
SOUTHWESTERN SOUTH PLAINS OVER THE NEXT SEVERAL HOURS. THE
PREVIOUSLY ISSUED WINTER WEATHER ADVISORY IN THE SOUTHWESTERN SOUTH
PLAINS STILL SEEMS MORE THAN ADEQUATE BARRING UNEXPECTED LIFT
FURTHER NORTH OR EAST AND LIKELY WILL EXPIRE AT 12Z IF NOT EARLIER.
REMAINING LIGHT SNOW OR SNOW SHOWERS SHOULD FADE AROUND MID MORNING.
IN SPITE OF DRYING TRENDS ON BACK SIDE OF THIS WAVE...SHORT TERM
WRF/NAM CONTINUES TO INDICATE A WEAK CONVECTIVE SIGNAL AROUND MID
DAY INTO AT LEAST EARLY AFTERNOON AND WE HAVE RETAINED LIGHT RAIN
SHOWER POSSIBILITY THIS AREA. FURTHER DRYING AND CLEARING WILL OCCUR
LATER TODAY AND OVERNIGHT. MINOR CHANGES REMAINDER OF FORECAST.
RMCQUEEN
LONG TERM...
MEDIUM RANGE MODELS ARE BEGINNING TO SHOW A GLIMMER OF HOPE DEPICTING
A LITTLE MORE CONSISTENCY FOR THIS WEEKEND INTO EARLY NEXT WEEK.
BEFORE THEN...SURFACE LEE TROUGHING WILL RETURN ON THURSDAY AND
FRIDAY BUMPING TEMPERATURES BACK WELL ABOVE SEASONAL AVERAGES AS
PREVIOUSLY SEEN THIS WINTER SEASON ON THESE TYPES OF DAYS. A STRONG
COLD FRONT WILL MAKE ITS WAY INTO THE AREA ON SATURDAY AHEAD OF A
SURFACE RIDGE SPILLING INTO THE PLAINS AND MIDWEST YET AGAIN. MODELS
SHOW COLD 850MB TEMPERATURES BETWEEN -6 AND -9C BY MONDAY MORNING.
BOTH THE GFS AND ECMWF HAVE BEEN SHOWING VERY LIGHT QPF AMOUNTS ON
SUNDAY AND MONDAY NEXT WEEK. MOST OF THIS ACTIVITY IS DICTATED BY
ISENTROPIC LIFT WITH NEARLY ZONAL FLOW ALOFT. THESE TYPES OF
PATTERNS WHICH ARE DOMINATED BY UPGLIDE TEND TO BE VERY LIGHT IN
PRECIPITATION AMOUNTS AND ARE USUALLY DEFINED BY DRIZZLE. WITH THE
COLD AIR IN PLACE WE COULD SEE A WINTRY MIX OF FZRA/FZDZ EARLY NEXT
WEEK.
&&
.PRELIMINARY POINT TEMPS/POPS...
FRIONA 44 22 55 29 / 20 0 0 0
TULIA 45 24 55 29 / 20 0 0 0
PLAINVIEW 47 25 56 30 / 20 0 0 0
LEVELLAND 47 26 61 31 / 30 0 0 0
LUBBOCK 48 26 60 31 / 20 0 0 0
DENVER CITY 47 27 62 31 / 30 0 0 0
BROWNFIELD 46 26 61 32 / 30 0 0 0
CHILDRESS 53 25 56 29 / 20 0 0 0
SPUR 50 28 60 32 / 20 0 0 0
ASPERMONT 52 28 62 33 / 20 0 0 0
&&
.LUB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
99/99/
AREA FORECAST DISCUSSION
NWS AUSTIN/SAN ANTONIO TX
935 AM CST TUE FEB 17 2015
.UPDATE...
ONLY RETURNS LEFT ON RADAR AT 930AM WERE LOCATED OVER
KARNES...DEWITT...AND LAVACA COUNTIES AND ON ITS WAY OUT. FOR THE
REST OF THE DAY...NOT EXPECTING ANY OTHER PRECIP AND CLOUDS WILL
BE ON THE DECREASE.
PERFORMED THE TYPICAL OBS BLEND INTO FORECAST HOURLIES AS WELL AS
REMOVING POPS FROM THE GRIDS FOR THE REMAINDER OF THE MORNING.
TB3
&&
.PREV DISCUSSION... /ISSUED 550 AM CST TUE FEB 17 2015/
AVIATION... /12Z TAF UPDATE/
AREAS OF LIGHT RAIN MIXED WITH SLEET AND SNOW CONTINUE TRACKING
EAST FROM THE EDWARDS PLATEAU INTO THE HILL COUNTRY AND CENTRAL
TX. A FEW SNOW AND SLEET REPORTS ARE BEGINNING TO TRICKLE IN OVER
THE NORTHERN HILL COUNTRY...AND THE RADAR ECHOES AND MODEL
SOUNDING DATA LOOK FAVORABLE FOR SOME OF THIS ACTIVITY TO REACH
THE AUS VCNTY FOR A FEW HOURS. MIXED PRECIP LOOKS LESS CERTAIN FOR
SAT/SSF/DRT...AND WILL HANDLE THESE AREAS SHOULD RADAR ECHOES
STRENGTHEN SOUTHWARD. MOST OF THE CIGS ARE HOLDING IN THE VFR
CATEGORY...AND RADAR TRENDS CONTINUE ON A SLOW DECREASE. THUS WILL
KEEP VFR SKIES OVER THE AREA TAF SITES. SOME ADDED GUSTS PICKED UP
THIS MORNING ALONG I-35 WHERE A SLIGHT TIGHTENING OF THE PRESSURE
GRADIENT WAS NOTED. BY 18Z...PRECIP SHOULD BE OUT OF THE TAF
LOCATIONS...AND CLOUDS AND WINDS SHOULD BOTH BE TRENDING
DOWNWARD...AND MOSTLY CLEAR SKIES WITH LIGHT WINDS ARE EXPECTED
TONIGHT.
PREV DISCUSSION... /ISSUED 330 AM CST TUE FEB 17 2015/
SHORT TERM (TODAY THROUGH WEDNESDAY)...FINAL PIECE OF MID LEVEL
FORCING IN THE BASE OF THE TROUGH WILL ROTATE THROUGH THE CWA THIS
MORNING. HAVE FOLLOWED SLIGHTLY CLOSER TO THE HRRR THROUGH MIDDAY
GIVEN THE BETTER HANDLING OF WHERE PRECIP IS CURRENTLY FALLING
ACROSS SOUTHERN AREAS OF SJT AND MAF CWAS. THAT SAID...THERE IS A
SIGNIFICANT DRY LAYER BELOW 800MB ACROSS NORTHERN AND EASTERN
AREAS OF THE CWA...WHICH MAY PREVENT MUCH OF THE PRECIP FROM REACHING
THE GROUND (ESPECIALLY NORTH OF A LLANO TO AUSTIN TO SCHULLENBURG
LINE). WHERE PRECIP DOES REACH THE GROUND...COLUMN WILL BE COOL
ENOUGH ALONG AND WEST OF I-35 FOR LIGHT SLEET OR SNOW FLURRIES TO
MIX IN...ESPECIALLY ACROSS CENTRAL AND WESTERN HILL COUNTRY. THERE
WAS SOME -SN REPORTED EARLIER IN OZONA. GROUND TEMPERATURES FOR
MOST LOCATIONS WILL REMAIN ABOVE FREEZING AND THEREFORE GENERALLY
NO ACCUMULATION IS EXPECTED. HOWEVER...CAN NOT RULE OUT SOME VERY
PATCHY...ELEVATED SURFACES ACROSS THE NORTHERN HILL COUNTRY SEEING
SOME VERY LIGHT ACCUMULATIONS. OVERALL...NOT ENOUGH TO WARRANT AN
ADVISORY...BUT WILL ISSUE AN SPS.
CLEARING WILL TAKE PLACE WEST TO EAST THIS AFTERNOON AND EVENING.
CLEAR SKIES AND LIGHT WINDS...WITH LOW LEVEL RIDGE AXIS OVER THE
CWA...WILL LEAD TO A COLD NIGHT. LOWS WEDNESDAY MORNING DIP INTO
THE MID AND UPPER 20S ACROSS THE HILL COUNTRY AND LOW TO MID 30S
ELSEWHERE. HIGHS REBOUND INTO THE MID 60S UNDER SUNNY SKIES
WEDNESDAY.
JR
LONG TERM (WEDNESDAY NIGHT THROUGH MONDAY)...A WARMING TREND WILL
OCCUR THURSDAY THROUGH SATURDAY ACROSS THE CWA...WITH TEMPERATURES
BACK ABOVE NORMAL FRIDAY AND SATURDAY. LOW LEVEL RETURN FLOW WILL
DEVELOP OVER THE AREA ON THURSDAY...WITH A RETURN OF CLOUDS
THURSDAY NIGHT. PATCHY DRIZZLE AND ISOLATED SHOWERS POSSIBLE
MAINLY ALONG AND EAST OF I-35 FRIDAY AND SATURDAY. ECMWF AND GFS
IN GENERAL AGREEMENT WITH THE NEXT COLD FRONT MOVING THROUGH
SOUTH-CENTRAL TEXAS SUNDAY MORNING. ISENTROPIC UPGLIDE PATTERN
DEVELOPS OVER THE SHALLOW...COLD AIRMASS LEADING TO CLOUDY AND MUCH
COLDER CONDITIONS SUNDAY AND MONDAY ALONG WITH CHANCES FOR RAIN.
&&
.PRELIMINARY POINT TEMPS/POPS...
AUSTIN CAMP MABRY 51 35 65 40 71 / 20 0 0 0 0
AUSTIN BERGSTROM INTL AIRPORT 49 29 64 35 69 / 20 0 0 0 0
NEW BRAUNFELS MUNI AIRPORT 50 32 66 38 72 / 20 0 0 0 0
BURNET MUNI AIRPORT 49 32 62 37 68 / 20 0 0 0 0
DEL RIO INTL AIRPORT 53 35 67 43 72 / 20 0 0 0 0
GEORGETOWN MUNI AIRPORT 51 31 64 37 68 / 20 0 0 0 0
HONDO MUNI AIRPORT 53 30 65 37 73 / 30 0 0 0 0
SAN MARCOS MUNI AIRPORT 51 31 65 37 71 / 20 0 0 0 0
LA GRANGE - FAYETTE REGIONAL 51 33 65 38 71 / 20 0 0 0 0
SAN ANTONIO INTL AIRPORT 52 33 65 40 71 / 30 0 0 0 0
STINSON MUNI AIRPORT 53 33 65 39 72 / 30 0 0 0 0
&&
.EWX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
MESOSCALE/AVIATION...24
SYNOPTIC/GRIDS...03
PUBLIC SERVICE/DATA COLLECTION...33
AREA FORECAST DISCUSSION
NWS LUBBOCK TX
626 AM CST TUE FEB 17 2015
.UPDATE...
DWINDLING SNOW ON RADAR THOUGH WITH LIGHT BANDS STILL TO FOLLOW
SEEMS IN LINE WITH LATEST RAP RUN. ALLOWED WINTER WEATHER ADVISORY
TO EXPIRE SOUTHWESTERN SOUTH PLAINS...DO NOT ANTICIPATE MORE THAN
A DUSTING REMAINDER OF THE AREA WITH SNOW MOSTLY ENDING BY 15Z.
RMCQUEEN
&&
.PREV DISCUSSION... /ISSUED 537 AM CST TUE FEB 17 2015/
AVIATION...
LIGHT SNOW WILL DWINDLE OVER THE NEXT COUPLE HOURS ACROSS THE SOUTHERN
SOUTH PLAINS INCLUDING KLBB WITH MVFR DOMINATING THROUGH 13Z OR 14Z.
BOTH KPVW AND KCDS APPEAR TOO DISTANT FROM THE BULK OF LIFT AND
DEEPER MOISTURE TO MENTION LINGERING SNOW CHANCES. DOWNSLOPE DRYING
WILL INCREASE MID TO LATE MORNING THOUGH STILL JUST ENOUGH MOISTURE
PERHAPS FOR A CUMULUS FIELD CONNECTED WITH MID LEVEL COOL POCKET
PASSING OVERHEAD. DRY AND VFR OVERNIGHT. RMCQUEEN
PREV DISCUSSION... /ISSUED 320 AM CST TUE FEB 17 2015/
SHORT TERM...
UPPER LEVEL IMPULSE TRANSLATING THROUGH THE AREA THIS MORNING RIGHT
ON SCHEDULE...AND DIRECTED MORE TOWARDS SOUTHERN ZONES WITH LIFT AND
SLIGHTLY DEEPER MOISTURE. THE MID LEVEL LIFT OVERNIGHT SO FAR HAS
SUCCEEDED IN MODEST TOP-DOWN MOISTENING AND SURFACE DEW-POINTS LATELY
HAVE RISEN OVER SOUTHERN ZONES AT LEAST TO THE POINT WHERE LIGHT
SNOW OR SNOW SHOWERS COULD REACH THE GROUND OVER A LARGER AREA. WITH
THAT...HOWEVER...THE RECENT RAP TRENDS SUPPORT ONLY A BRIEF
OPPORTUNITY FOR MOSTLY INSIGNIFICANT ACCUMULATIONS ACROSS MAINLY THE
SOUTHWESTERN SOUTH PLAINS OVER THE NEXT SEVERAL HOURS. THE
PREVIOUSLY ISSUED WINTER WEATHER ADVISORY IN THE SOUTHWESTERN SOUTH
PLAINS STILL SEEMS MORE THAN ADEQUATE BARRING UNEXPECTED LIFT
FURTHER NORTH OR EAST AND LIKELY WILL EXPIRE AT 12Z IF NOT EARLIER.
REMAINING LIGHT SNOW OR SNOW SHOWERS SHOULD FADE AROUND MID MORNING.
IN SPITE OF DRYING TRENDS ON BACK SIDE OF THIS WAVE...SHORT TERM
WRF/NAM CONTINUES TO INDICATE A WEAK CONVECTIVE SIGNAL AROUND MID
DAY INTO AT LEAST EARLY AFTERNOON AND WE HAVE RETAINED LIGHT RAIN
SHOWER POSSIBILITY THIS AREA. FURTHER DRYING AND CLEARING WILL OCCUR
LATER TODAY AND OVERNIGHT. MINOR CHANGES REMAINDER OF FORECAST.
RMCQUEEN
LONG TERM...
MEDIUM RANGE MODELS ARE BEGINNING TO SHOW A GLIMMER OF HOPE DEPICTING
A LITTLE MORE CONSISTENCY FOR THIS WEEKEND INTO EARLY NEXT WEEK.
BEFORE THEN...SURFACE LEE TROUGHING WILL RETURN ON THURSDAY AND
FRIDAY BUMPING TEMPERATURES BACK WELL ABOVE SEASONAL AVERAGES AS
PREVIOUSLY SEEN THIS WINTER SEASON ON THESE TYPES OF DAYS. A STRONG
COLD FRONT WILL MAKE ITS WAY INTO THE AREA ON SATURDAY AHEAD OF A
SURFACE RIDGE SPILLING INTO THE PLAINS AND MIDWEST YET AGAIN. MODELS
SHOW COLD 850MB TEMPERATURES BETWEEN -6 AND -9C BY MONDAY MORNING.
BOTH THE GFS AND ECMWF HAVE BEEN SHOWING VERY LIGHT QPF AMOUNTS ON
SUNDAY AND MONDAY NEXT WEEK. MOST OF THIS ACTIVITY IS DICTATED BY
ISENTROPIC LIFT WITH NEARLY ZONAL FLOW ALOFT. THESE TYPES OF
PATTERNS WHICH ARE DOMINATED BY UPGLIDE TEND TO BE VERY LIGHT IN
PRECIPITATION AMOUNTS AND ARE USUALLY DEFINED BY DRIZZLE. WITH THE
COLD AIR IN PLACE WE COULD SEE A WINTRY MIX OF FZRA/FZDZ EARLY NEXT
WEEK.
&&
.PRELIMINARY POINT TEMPS/POPS...
FRIONA 44 22 55 29 / 20 0 0 0
TULIA 45 24 55 29 / 20 0 0 0
PLAINVIEW 47 25 56 30 / 20 0 0 0
LEVELLAND 47 26 61 31 / 30 0 0 0
LUBBOCK 48 26 60 31 / 20 0 0 0
DENVER CITY 47 27 62 31 / 30 0 0 0
BROWNFIELD 46 26 61 32 / 30 0 0 0
CHILDRESS 53 25 56 29 / 20 0 0 0
SPUR 50 28 60 32 / 20 0 0 0
ASPERMONT 52 28 62 33 / 20 0 0 0
&&
.LUB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
05/99
AREA FORECAST DISCUSSION
NWS HOUSTON/GALVESTON TX
612 AM CST TUE FEB 17 2015
.DISCUSSION...
12Z TAF DISCUSSION IN AVIATION SECTION...
&&
.AVIATION...
WATCHING A SHORT WAVE TROUGH ON WATER VAPOR IMAGERY OVER C TX
WHICH SHOULD MOVE EAST DURING THE DAY TODAY. PRECIP WITH THIS WAVE
SHOULD STAY NORTH OF MOST OF THE TERMINALS BUT STILL A SMALL
CHANCE OF A FEW SHOWERS. WILL LEAVE OUT MENTION OF PRECIP FOR NOW
AS ANY PRECIP WILL BE SHORT LIVED. COLD ADVECTION SHOULD BE STRONG
ENOUGH TO SLOWLY ERODE MVFR CIGS THIS MORNING AS THE WAVE PULLS
EAST OF THE AREA. THINK CIGS BECOME VFR 16-18Z WITH SKIES CLEARING
THROUGH THE AFTERNOON. HIGH PRESSURE BUILDING THROUGH TEXAS WILL
SUPPORT LIGHT WINDS AND CLEAR SKIES TONIGHT.
39
&&
.PREV DISCUSSION... /ISSUED 327 AM CST TUE FEB 17 2015/
DISCUSSION...
RAIN FROM EARLIER THIS MORNING HAS PUSHED OFF THE COAST LEAVING
CLOUDY AND COLD CONDITIONS IN ITS WAKE. THERE IS CURRENTLY SOME
VERY LIGHT SNOW BEING REPORTED IN THE TEXAS HILL COUNTRY THAT IS
SLOWLY FALLING APART AS IT PUSHES TO THE EAST. THE HRRR HAS BEEN
THE MODEL OF CHOICE THIS MORNING AND HAS SOME VERY LIGHT
REFLECTIVITY MAKING IT INTO THE AREA JUST AFTER SUNRISE THIS
MORNING. ANY PRECIP WILL BE FIGHTING VERY DRY AIR THOUGH BETWEEN
700 AND 850 MB. IF SOME PRECIP DOES REACH THE GROUND IT WILL
PROBABLY HIT THE GROUND AS SLEET. WE WILL CONTINUE TO WATCH THE
LIGHT PRECIP OUT WEST AND MAKE ADJUSTMENTS TO THE FORECAST AS
NEEDED.
AFTER THE PRECIP EXITS THE AREA THIS MORNING SKIES WILL BEGIN TO
GRADUALLY CLEAR FROM WEST TO EAST THIS AFTERNOON AS DRIER AIR
WORKS IN FROM THE NORTH. WEDNESDAY MORNING STILL LOOKS COLD AS
SURFACE HIGH PRESSURE MOVES OVERHEAD. DURING THE DAY WEDNESDAY THE
WARMING TREND WILL START AS SURFACE HIGH PRESSURE BEGINS TO PUSH
EAST. THE CHANCE OF RAIN THEN RETURNS TO THE FORECAST STARTING
FRIDAY AFTERNOON AHEAD OF THE NEXT UPPER LEVEL SYSTEM DIVING SOUTH
OVER THE WEST COAST. MODELS HAVE STRUGGLED WITH THIS DISTURBANCE
THE LAST COUPLE OF DAYS BUT SEEM TO BE CONVERGING ON A SOLUTION.
THE GFS... ECMWF... AND CMC ALL DIVE THE ENERGY SOUTHWARDS AND
FORM A CUT OFF LOW NEAR THE NEVADA/ CALIFORNIA BORDER. STILL
THERE REMAINS DIFFERENCES IN THE COLD FRONT TIMING FOR SUNDAY WITH
THE EURO BEING THE FASTEST AND THE GFS BEING SLIGHT SLOWER. FOR
NOW HAVE TRENDED TOWARDS THE EURO WHICH BRINGS THE FRONT THROUGH
SUNDAY MORNING. ISENTROPIC UPGLIDE THEN LOOKS TO COMMENCE ALLOWING
THE CHANCE OF RAIN TO REMAIN IN THE FORECAST THROUGH THE BEGINNING
OF THE NEXT WORK WEEK. 23
MARINE...
STRONG COLD FRONT HAS PUSHED INTO THE GULF WITH STRONG NORTHERLY
WINDS BEHIND IT THIS MORNING. WINDS SHOULD BE DECREASING THROUGH THE
MORNING AND WILL KEEP A SCA FOR THE OFFSHORE WATERS OF THE UPPER TX
COAST. SCEC WILL BE IN EFFECT FOR THE NEAR SHORE WATERS AND BAYS.
HIGH PRESSURE BUILDS OVER THE REGION TONIGHT INTO WED ALLOWING FOR
LIGHT WINDS AND LOW SEAS.
MODELS STILL SHOW STRONG SE WINDS DEVELOPING THUR AND PERSISTING
THROUGH SATURDAY. LONG SOUTHERLY FETCH SHOULD BUILD SEAS TO NEAR 6FT
NEAR SHORE AND 9-10FT OFFSHORE SO SCA WILL BE LIKELY. COLD FRONT
SHOULD PUSH OFF THE COAST DURING THE DAY SUNDAY AND TURN WINDS TO
THE N/NE. SCA WILL LIKELY BE NEEDED AGAIN BUT FOR OFFSHORE WINDS.
ECMWF SHOWING THE FRONT COULD PUSH THROUGH SUN MORNING INSTEAD OF
LATER IN THE DAY. FORECAST WAS TRENDED IN THIS DIRECTION.
39
&&
.PRELIMINARY POINT TEMPS/POPS...
COLLEGE STATION (CLL) 48 35 63 38 64 / 20 0 0 0 0
HOUSTON (IAH) 49 34 64 38 64 / 20 0 0 0 0
GALVESTON (GLS) 49 42 61 47 62 / 20 0 0 0 0
&&
.HGX WATCHES/WARNINGS/ADVISORIES...
TX...NONE.
GM...SMALL CRAFT SHOULD EXERCISE CAUTION UNTIL 9 AM CST THIS MORNING
FOR THE FOLLOWING ZONES: GALVESTON BAY...MATAGORDA BAY...
WATERS FROM FREEPORT TO THE MATAGORDA SHIP CHANNEL OUT 20
NM...WATERS FROM HIGH ISLAND TO FREEPORT OUT 20 NM.
SMALL CRAFT ADVISORY UNTIL 9 AM CST THIS MORNING FOR THE
FOLLOWING ZONES: WATERS FROM FREEPORT TO THE MATAGORDA SHIP
CHANNEL 20 NM TO 60 NM...WATERS FROM HIGH ISLAND TO
FREEPORT 20 TO 60 NM.
&&
$$
DISCUSSION...23
AVIATION/MARINE...39
AREA FORECAST DISCUSSION
NWS AUSTIN/SAN ANTONIO TX
550 AM CST TUE FEB 17 2015
.AVIATION... /12Z TAF UPDATE/
AREAS OF LIGHT RAIN MIXED WITH SLEET AND SNOW CONTINUE TRACKING
EAST FROM THE EDWARDS PLATEAU INTO THE HILL COUNTRY AND CENTRAL
TX. A FEW SNOW AND SLEET REPORTS ARE BEGINNING TO TRICKLE IN OVER
THE NORTHERN HILL COUNTRY...AND THE RADAR ECHOES AND MODEL
SOUNDING DATA LOOK FAVORABLE FOR SOME OF THIS ACTIVITY TO REACH
THE AUS VCNTY FOR A FEW HOURS. MIXED PRECIP LOOKS LESS CERTAIN FOR
SAT/SSF/DRT...AND WILL HANDLE THESE AREAS SHOULD RADAR ECHOES
STRENGTHEN SOUTHWARD. MOST OF THE CIGS ARE HOLDING IN THE VFR
CATEGORY...AND RADAR TRENDS CONTINUE ON A SLOW DECREASE. THUS WILL
KEEP VFR SKIES OVER THE AREA TAF SITES. SOME ADDED GUSTS PICKED UP
THIS MORNING ALONG I-35 WHERE A SLIGHT TIGHTENING OF THE PRESSURE
GRADIENT WAS NOTED. BY 18Z...PRECIP SHOULD BE OUT OF THE TAF
LOCATIONS...AND CLOUDS AND WINDS SHOULD BOTH BE TRENDING
DOWNWARD...AND MOSTLY CLEAR SKIES WITH LIGHT WINDS ARE EXPECTED
TONIGHT.
&&
.PREV DISCUSSION... /ISSUED 330 AM CST TUE FEB 17 2015/
SHORT TERM (TODAY THROUGH WEDNESDAY)...FINAL PIECE OF MID LEVEL
FORCING IN THE BASE OF THE TROUGH WILL ROTATE THROUGH THE CWA THIS
MORNING. HAVE FOLLOWED SLIGHTLY CLOSER TO THE HRRR THROUGH MIDDAY
GIVEN THE BETTER HANDLING OF WHERE PRECIP IS CURRENTLY FALLING
ACROSS SOUTHERN AREAS OF SJT AND MAF CWAS. THAT SAID...THERE IS A
SIGNIFICANT DRY LAYER BELOW 800MB ACROSS NORTHERN AND EASTERN
AREAS OF THE CWA...WHICH MAY PREVENT MUCH OF THE PRECIP FROM REACHING
THE GROUND (ESPECIALLY NORTH OF A LLANO TO AUSTIN TO SCHULLENBURG
LINE). WHERE PRECIP DOES REACH THE GROUND...COLUMN WILL BE COOL
ENOUGH ALONG AND WEST OF I-35 FOR LIGHT SLEET OR SNOW FLURRIES TO
MIX IN...ESPECIALLY ACROSS CENTRAL AND WESTERN HILL COUNTRY. THERE
WAS SOME -SN REPORTED EARLIER IN OZONA. GROUND TEMPERATURES FOR
MOST LOCATIONS WILL REMAIN ABOVE FREEZING AND THEREFORE GENERALLY
NO ACCUMULATION IS EXPECTED. HOWEVER...CAN NOT RULE OUT SOME VERY
PATCHY...ELEVATED SURFACES ACROSS THE NORTHERN HILL COUNTRY SEEING
SOME VERY LIGHT ACCUMULATIONS. OVERALL...NOT ENOUGH TO WARRANT AN
ADVISORY...BUT WILL ISSUE AN SPS.
CLEARING WILL TAKE PLACE WEST TO EAST THIS AFTERNOON AND EVENING.
CLEAR SKIES AND LIGHT WINDS...WITH LOW LEVEL RIDGE AXIS OVER THE
CWA...WILL LEAD TO A COLD NIGHT. LOWS WEDNESDAY MORNING DIP INTO
THE MID AND UPPER 20S ACROSS THE HILL COUNTRY AND LOW TO MID 30S
ELSEWHERE. HIGHS REBOUND INTO THE MID 60S UNDER SUNNY SKIES
WEDNESDAY.
JR
LONG TERM (WEDNESDAY NIGHT THROUGH MONDAY)...A WARMING TREND WILL
OCCUR THURSDAY THROUGH SATURDAY ACROSS THE CWA...WITH TEMPERATURES
BACK ABOVE NORMAL FRIDAY AND SATURDAY. LOW LEVEL RETURN FLOW WILL
DEVELOP OVER THE AREA ON THURSDAY...WITH A RETURN OF CLOUDS
THURSDAY NIGHT. PATCHY DRIZZLE AND ISOLATED SHOWERS POSSIBLE
MAINLY ALONG AND EAST OF I-35 FRIDAY AND SATURDAY. ECMWF AND GFS
IN GENERAL AGREEMENT WITH THE NEXT COLD FRONT MOVING THROUGH
SOUTH-CENTRAL TEXAS SUNDAY MORNING. ISENTROPIC UPGLIDE PATTERN
DEVELOPS OVER THE SHALLOW...COLD AIRMASS LEADING TO CLOUDY AND MUCH
COLDER CONDITIONS SUNDAY AND MONDAY ALONG WITH CHANCES FOR RAIN.
&&
.PRELIMINARY POINT TEMPS/POPS...
AUSTIN CAMP MABRY 51 35 65 40 71 / 20 0 0 0 0
AUSTIN BERGSTROM INTL AIRPORT 49 29 64 35 69 / 20 0 0 0 0
NEW BRAUNFELS MUNI AIRPORT 50 32 66 38 72 / 20 0 0 0 0
BURNET MUNI AIRPORT 49 32 62 37 68 / 20 0 0 0 0
DEL RIO INTL AIRPORT 53 35 67 43 72 / 20 0 0 0 0
GEORGETOWN MUNI AIRPORT 51 31 64 37 68 / 20 0 0 0 0
HONDO MUNI AIRPORT 53 30 65 37 73 / 30 0 0 0 0
SAN MARCOS MUNI AIRPORT 51 31 65 37 71 / 20 0 0 0 0
LA GRANGE - FAYETTE REGIONAL 51 33 65 38 71 / 20 0 0 0 0
SAN ANTONIO INTL AIRPORT 52 33 65 40 71 / 30 0 0 0 0
STINSON MUNI AIRPORT 53 33 65 39 72 / 30 0 0 0 0
&&
.EWX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
MESOSCALE/AVIATION...18
SYNOPTIC/GRIDS...76
AREA FORECAST DISCUSSION
NWS LUBBOCK TX
537 AM CST TUE FEB 17 2015
.AVIATION...
LIGHT SNOW WILL DWINDLE OVER THE NEXT COUPLE HOURS ACROSS THE SOUTHERN
SOUTH PLAINS INCLUDING KLBB WITH MVFR DOMINATING THROUGH 13Z OR 14Z.
BOTH KPVW AND KCDS APPEAR TOO DISTANT FROM THE BULK OF LIFT AND
DEEPER MOISTURE TO MENTION LINGERING SNOW CHANCES. DOWNSLOPE DRYING
WILL INCREASE MID TO LATE MORNING THOUGH STILL JUST ENOUGH MOISTURE
PERHAPS FOR A CUMULUS FIELD CONNECTED WITH MID LEVEL COOL POCKET
PASSING OVERHEAD. DRY AND VFR OVERNIGHT. RMCQUEEN
&&
.PREV DISCUSSION... /ISSUED 320 AM CST TUE FEB 17 2015/
SHORT TERM...
UPPER LEVEL IMPULSE TRANSLATING THROUGH THE AREA THIS MORNING RIGHT
ON SCHEDULE...AND DIRECTED MORE TOWARDS SOUTHERN ZONES WITH LIFT AND
SLIGHTLY DEEPER MOISTURE. THE MID LEVEL LIFT OVERNIGHT SO FAR HAS
SUCCEEDED IN MODEST TOP-DOWN MOISTENING AND SURFACE DEW-POINTS LATELY
HAVE RISEN OVER SOUTHERN ZONES AT LEAST TO THE POINT WHERE LIGHT
SNOW OR SNOW SHOWERS COULD REACH THE GROUND OVER A LARGER AREA. WITH
THAT...HOWEVER...THE RECENT RAP TRENDS SUPPORT ONLY A BRIEF
OPPORTUNITY FOR MOSTLY INSIGNIFICANT ACCUMULATIONS ACROSS MAINLY THE
SOUTHWESTERN SOUTH PLAINS OVER THE NEXT SEVERAL HOURS. THE
PREVIOUSLY ISSUED WINTER WEATHER ADVISORY IN THE SOUTHWESTERN SOUTH
PLAINS STILL SEEMS MORE THAN ADEQUATE BARRING UNEXPECTED LIFT
FURTHER NORTH OR EAST AND LIKELY WILL EXPIRE AT 12Z IF NOT EARLIER.
REMAINING LIGHT SNOW OR SNOW SHOWERS SHOULD FADE AROUND MID MORNING.
IN SPITE OF DRYING TRENDS ON BACK SIDE OF THIS WAVE...SHORT TERM
WRF/NAM CONTINUES TO INDICATE A WEAK CONVECTIVE SIGNAL AROUND MID
DAY INTO AT LEAST EARLY AFTERNOON AND WE HAVE RETAINED LIGHT RAIN
SHOWER POSSIBILITY THIS AREA. FURTHER DRYING AND CLEARING WILL OCCUR
LATER TODAY AND OVERNIGHT. MINOR CHANGES REMAINDER OF FORECAST.
RMCQUEEN
LONG TERM...
MEDIUM RANGE MODELS ARE BEGINNING TO SHOW A GLIMMER OF HOPE DEPICTING
A LITTLE MORE CONSISTENCY FOR THIS WEEKEND INTO EARLY NEXT WEEK.
BEFORE THEN...SURFACE LEE TROUGHING WILL RETURN ON THURSDAY AND
FRIDAY BUMPING TEMPERATURES BACK WELL ABOVE SEASONAL AVERAGES AS
PREVIOUSLY SEEN THIS WINTER SEASON ON THESE TYPES OF DAYS. A STRONG
COLD FRONT WILL MAKE ITS WAY INTO THE AREA ON SATURDAY AHEAD OF A
SURFACE RIDGE SPILLING INTO THE PLAINS AND MIDWEST YET AGAIN. MODELS
SHOW COLD 850MB TEMPERATURES BETWEEN -6 AND -9C BY MONDAY MORNING.
BOTH THE GFS AND ECMWF HAVE BEEN SHOWING VERY LIGHT QPF AMOUNTS ON
SUNDAY AND MONDAY NEXT WEEK. MOST OF THIS ACTIVITY IS DICTATED BY
ISENTROPIC LIFT WITH NEARLY ZONAL FLOW ALOFT. THESE TYPES OF
PATTERNS WHICH ARE DOMINATED BY UPGLIDE TEND TO BE VERY LIGHT IN
PRECIPITATION AMOUNTS AND ARE USUALLY DEFINED BY DRIZZLE. WITH THE
COLD AIR IN PLACE WE COULD SEE A WINTRY MIX OF FZRA/FZDZ EARLY NEXT
WEEK.
&&
.PRELIMINARY POINT TEMPS/POPS...
FRIONA 44 22 55 29 / 20 0 0 0
TULIA 45 24 55 29 / 20 0 0 0
PLAINVIEW 47 25 56 30 / 20 0 0 0
LEVELLAND 47 26 61 31 / 30 0 0 0
LUBBOCK 48 26 60 31 / 20 0 0 0
DENVER CITY 47 27 62 31 / 30 0 0 0
BROWNFIELD 46 26 61 32 / 30 0 0 0
CHILDRESS 53 25 56 29 / 20 0 0 0
SPUR 50 28 60 32 / 20 0 0 0
ASPERMONT 52 28 62 33 / 20 0 0 0
&&
.LUB WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY UNTIL 6 AM CST EARLY THIS MORNING FOR
TXZ039-040.
&&
$$
99/99/05
AREA FORECAST DISCUSSION
NWS AUSTIN/SAN ANTONIO TX
330 AM CST TUE FEB 17 2015
.SHORT TERM (TODAY THROUGH WEDNESDAY)...FINAL PIECE OF MID LEVEL
FORCING IN THE BASE OF THE TROUGH WILL ROTATE THROUGH THE CWA THIS
MORNING. HAVE FOLLOWED SLIGHTLY CLOSER TO THE HRRR THROUGH MIDDAY
GIVEN THE BETTER HANDLING OF WHERE PRECIP IS CURRENTLY FALLING
ACROSS SOUTHERN AREAS OF SJT AND MAF CWAS. THAT SAID...THERE IS A
SIGNIFICANT DRY LAYER BELOW 800MB ACROSS NORTHERN AND EASTERN
AREAS OF THE CWA...WHICH MAY PREVENT MUCH OF THE PRECIP FROM REACHING
THE GROUND (ESPECIALLY NORTH OF A LLANO TO AUSTIN TO SCHULLENBURG
LINE). WHERE PRECIP DOES REACH THE GROUND...COLUMN WILL BE COOL
ENOUGH ALONG AND WEST OF I-35 FOR LIGHT SLEET OR SNOW FLURRIES TO
MIX IN...ESPECIALLY ACROSS CENTRAL AND WESTERN HILL COUNTRY. THERE
WAS SOME -SN REPORTED EARLIER IN OZONA. GROUND TEMPERATURES FOR
MOST LOCATIONS WILL REMAIN ABOVE FREEZING AND THEREFORE GENERALLY
NO ACCUMULATION IS EXPECTED. HOWEVER...CAN NOT RULE OUT SOME VERY
PATCHY...ELEVATED SURFACES ACROSS THE NORTHERN HILL COUNTRY SEEING
SOME VERY LIGHT ACCUMULATIONS. OVERALL...NOT ENOUGH TO WARRANT AN
ADVISORY...BUT WILL ISSUE AN SPS.
CLEARING WILL TAKE PLACE WEST TO EAST THIS AFTERNOON AND EVENING.
CLEAR SKIES AND LIGHT WINDS...WITH LOW LEVEL RIDGE AXIS OVER THE
CWA...WILL LEAD TO A COLD NIGHT. LOWS WEDNESDAY MORNING DIP INTO
THE MID AND UPPER 20S ACROSS THE HILL COUNTRY AND LOW TO MID 30S
ELSEWHERE. HIGHS REBOUND INTO THE MID 60S UNDER SUNNY SKIES
WEDNESDAY.
JR
&&
.LONG TERM (WEDNESDAY NIGHT THROUGH MONDAY)...A WARMING TREND WILL
OCCUR THURSDAY THROUGH SATURDAY ACROSS THE CWA...WITH TEMPERATURES
BACK ABOVE NORMAL FRIDAY AND SATURDAY. LOW LEVEL RETURN FLOW WILL
DEVELOP OVER THE AREA ON THURSDAY...WITH A RETURN OF CLOUDS
THURSDAY NIGHT. PATCHY DRIZZLE AND ISOLATED SHOWERS POSSIBLE
MAINLY ALONG AND EAST OF I-35 FRIDAY AND SATURDAY. ECMWF AND GFS
IN GENERAL AGREEMENT WITH THE NEXT COLD FRONT MOVING THROUGH
SOUTH-CENTRAL TEXAS SUNDAY MORNING. ISENTROPIC UPGLIDE PATTERN
DEVELOPS OVER THE SHALLOW...COLD AIRMASS LEADING TO CLOUDY AND MUCH
COLDER CONDITIONS SUNDAY AND MONDAY ALONG WITH CHANCES FOR RAIN.
&&
.PRELIMINARY POINT TEMPS/POPS...
AUSTIN CAMP MABRY 51 35 65 40 71 / 20 0 0 0 0
AUSTIN BERGSTROM INTL AIRPORT 49 29 64 35 69 / 20 0 0 0 0
NEW BRAUNFELS MUNI AIRPORT 50 32 66 38 72 / 20 0 0 0 0
BURNET MUNI AIRPORT 49 32 62 37 68 / 20 0 0 0 0
DEL RIO INTL AIRPORT 53 35 67 43 72 / 20 0 0 0 0
GEORGETOWN MUNI AIRPORT 51 31 64 37 68 / 20 0 0 0 0
HONDO MUNI AIRPORT 53 30 65 37 73 / 30 0 0 0 0
SAN MARCOS MUNI AIRPORT 51 31 65 37 71 / 20 0 0 0 0
LA GRANGE - FAYETTE REGIONAL 51 33 65 38 71 / 20 0 0 0 0
SAN ANTONIO INTL AIRPORT 52 33 65 40 71 / 30 0 0 0 0
STINSON MUNI AIRPORT 53 33 65 39 72 / 30 0 0 0 0
&&
.EWX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
MESOSCALE/AVIATION...18
SYNOPTIC/GRIDS...76
AREA FORECAST DISCUSSION
NWS HOUSTON/GALVESTON TX
327 AM CST TUE FEB 17 2015
.DISCUSSION...
RAIN FROM EARLIER THIS MORNING HAS PUSHED OFF THE COAST LEAVING
CLOUDY AND COLD CONDITIONS IN ITS WAKE. THERE IS CURRENTLY SOME
VERY LIGHT SNOW BEING REPORTED IN THE TEXAS HILL COUNTRY THAT IS
SLOWLY FALLING APART AS IT PUSHES TO THE EAST. THE HRRR HAS BEEN
THE MODEL OF CHOICE THIS MORNING AND HAS SOME VERY LIGHT
REFLECTIVITY MAKING IT INTO THE AREA JUST AFTER SUNRISE THIS
MORNING. ANY PRECIP WILL BE FIGHTING VERY DRY AIR THOUGH BETWEEN
700 AND 850 MB. IF SOME PRECIP DOES REACH THE GROUND IT WILL
PROBABLY HIT THE GROUND AS SLEET. WE WILL CONTINUE TO WATCH THE
LIGHT PRECIP OUT WEST AND MAKE ADJUSTMENTS TO THE FORECAST AS
NEEDED.
AFTER THE PRECIP EXITS THE AREA THIS MORNING SKIES WILL BEGIN TO
GRADUALLY CLEAR FROM WEST TO EAST THIS AFTERNOON AS DRIER AIR
WORKS IN FROM THE NORTH. WEDNESDAY MORNING STILL LOOKS COLD AS
SURFACE HIGH PRESSURE MOVES OVERHEAD. DURING THE DAY WEDNESDAY THE
WARMING TREND WILL START AS SURFACE HIGH PRESSURE BEGINS TO PUSH
EAST. THE CHANCE OF RAIN THEN RETURNS TO THE FORECAST STARTING
FRIDAY AFTERNOON AHEAD OF THE NEXT UPPER LEVEL SYSTEM DIVING SOUTH
OVER THE WEST COAST. MODELS HAVE STRUGGLED WITH THIS DISTURBANCE
THE LAST COUPLE OF DAYS BUT SEEM TO BE CONVERGING ON A SOLUTION.
THE GFS... ECMWF... AND CMC ALL DIVE THE ENERGY SOUTHWARDS AND
FORM A CUT OFF LOW NEAR THE NEVADA/ CALIFORNIA BORDER. STILL
THERE REMAINS DIFFERENCES IN THE COLD FRONT TIMING FOR SUNDAY WITH
THE EURO BEING THE FASTEST AND THE GFS BEING SLIGHT SLOWER. FOR
NOW HAVE TRENDED TOWARDS THE EURO WHICH BRINGS THE FRONT THROUGH
SUNDAY MORNING. ISENTROPIC UPGLIDE THEN LOOKS TO COMMENCE ALLOWING
THE CHANCE OF RAIN TO REMAIN IN THE FORECAST THROUGH THE BEGINNING
OF THE NEXT WORK WEEK. 23
&&
.MARINE...
STRONG COLD FRONT HAS PUSHED INTO THE GULF WITH STRONG NORTHERLY
WINDS BEHIND IT THIS MORNING. WINDS SHOULD BE DECREASING THROUGH THE
MORNING AND WILL KEEP A SCA FOR THE OFFSHORE WATERS OF THE UPPER TX
COAST. SCEC WILL BE IN EFFECT FOR THE NEAR SHORE WATERS AND BAYS.
HIGH PRESSURE BUILDS OVER THE REGION TONIGHT INTO WED ALLOWING FOR
LIGHT WINDS AND LOW SEAS.
MODELS STILL SHOW STRONG SE WINDS DEVELOPING THUR AND PERSISTING
THROUGH SATURDAY. LONG SOUTHERLY FETCH SHOULD BUILD SEAS TO NEAR 6FT
NEAR SHORE AND 9-10FT OFFSHORE SO SCA WILL BE LIKELY. COLD FRONT
SHOULD PUSH OFF THE COAST DURING THE DAY SUNDAY AND TURN WINDS TO
THE N/NE. SCA WILL LIKELY BE NEEDED AGAIN BUT FOR OFFSHORE WINDS.
ECMWF SHOWING THE FRONT COULD PUSH THROUGH SUN MORNING INSTEAD OF
LATER IN THE DAY. FORECAST WAS TRENDED IN THIS DIRECTION.
39
&&
.PRELIMINARY POINT TEMPS/POPS...
COLLEGE STATION (CLL) 48 35 63 38 64 / 20 0 0 0 0
HOUSTON (IAH) 49 34 64 38 64 / 20 0 0 0 0
GALVESTON (GLS) 49 42 61 47 62 / 20 0 0 0 0
&&
.HGX WATCHES/WARNINGS/ADVISORIES...
TX...NONE.
GM...SMALL CRAFT SHOULD EXERCISE CAUTION UNTIL 9 AM CST THIS MORNING
FOR THE FOLLOWING ZONES: GALVESTON BAY...MATAGORDA BAY...
WATERS FROM FREEPORT TO THE MATAGORDA SHIP CHANNEL OUT 20
NM...WATERS FROM HIGH ISLAND TO FREEPORT OUT 20 NM.
SMALL CRAFT ADVISORY UNTIL 9 AM CST THIS MORNING FOR THE
FOLLOWING ZONES: WATERS FROM FREEPORT TO THE MATAGORDA SHIP
CHANNEL 20 NM TO 60 NM...WATERS FROM HIGH ISLAND TO
FREEPORT 20 TO 60 NM.
&&
$$
DISCUSSION...23
AVIATION/MARINE...39
AREA FORECAST DISCUSSION
NWS LUBBOCK TX
320 AM CST TUE FEB 17 2015
.SHORT TERM...
UPPER LEVEL IMPULSE TRANSLATING THROUGH THE AREA THIS MORNING RIGHT
ON SCHEDULE...AND DIRECTED MORE TOWARDS SOUTHERN ZONES WITH LIFT AND
SLIGHTLY DEEPER MOISTURE. THE MID LEVEL LIFT OVERNIGHT SO FAR HAS
SUCCEEDED IN MODEST TOP-DOWN MOISTENING AND SURFACE DEW-POINTS LATELY
HAVE RISEN OVER SOUTHERN ZONES AT LEAST TO THE POINT WHERE LIGHT
SNOW OR SNOW SHOWERS COULD REACH THE GROUND OVER A LARGER AREA. WITH
THAT...HOWEVER...THE RECENT RAP TRENDS SUPPORT ONLY A BRIEF
OPPORTUNITY FOR MOSTLY INSIGNIFICANT ACCUMULATIONS ACROSS MAINLY THE
SOUTHWESTERN SOUTH PLAINS OVER THE NEXT SEVERAL HOURS. THE
PREVIOUSLY ISSUED WINTER WEATHER ADVISORY IN THE SOUTHWESTERN SOUTH
PLAINS STILL SEEMS MORE THAN ADEQUATE BARRING UNEXPECTED LIFT
FURTHER NORTH OR EAST AND LIKELY WILL EXPIRE AT 12Z IF NOT EARLIER.
REMAINING LIGHT SNOW OR SNOW SHOWERS SHOULD FADE AROUND MID MORNING.
IN SPITE OF DRYING TRENDS ON BACK SIDE OF THIS WAVE...SHORT TERM
WRF/NAM CONTINUES TO INDICATE A WEAK CONVECTIVE SIGNAL AROUND MID
DAY INTO AT LEAST EARLY AFTERNOON AND WE HAVE RETAINED LIGHT RAIN
SHOWER POSSIBILITY THIS AREA. FURTHER DRYING AND CLEARING WILL OCCUR
LATER TODAY AND OVERNIGHT. MINOR CHANGES REMAINDER OF FORECAST.
RMCQUEEN
.LONG TERM...
MEDIUM RANGE MODELS ARE BEGINNING TO SHOW A GLIMMER OF HOPE DEPICTING
A LITTLE MORE CONSISTENCY FOR THIS WEEKEND INTO EARLY NEXT WEEK.
BEFORE THEN...SURFACE LEE TROUGHING WILL RETURN ON THURSDAY AND
FRIDAY BUMPING TEMPERATURES BACK WELL ABOVE SEASONAL AVERAGES AS
PREVIOUSLY SEEN THIS WINTER SEASON ON THESE TYPES OF DAYS. A STRONG
COLD FRONT WILL MAKE ITS WAY INTO THE AREA ON SATURDAY AHEAD OF A
SURFACE RIDGE SPILLING INTO THE PLAINS AND MIDWEST YET AGAIN. MODELS
SHOW COLD 850MB TEMPERATURES BETWEEN -6 AND -9C BY MONDAY MORNING.
BOTH THE GFS AND ECMWF HAVE BEEN SHOWING VERY LIGHT QPF AMOUNTS ON
SUNDAY AND MONDAY NEXT WEEK. MOST OF THIS ACTIVITY IS DICTATED BY
ISENTROPIC LIFT WITH NEARLY ZONAL FLOW ALOFT. THESE TYPES OF
PATTERNS WHICH ARE DOMINATED BY UPGLIDE TEND TO BE VERY LIGHT IN
PRECIPITATION AMOUNTS AND ARE USUALLY DEFINED BY DRIZZLE. WITH THE
COLD AIR IN PLACE WE COULD SEE A WINTRY MIX OF FZRA/FZDZ EARLY NEXT
WEEK.
&&
.PRELIMINARY POINT TEMPS/POPS...
FRIONA 44 22 55 29 / 20 0 0 0
TULIA 45 24 55 29 / 20 0 0 0
PLAINVIEW 47 25 56 30 / 20 0 0 0
LEVELLAND 47 26 61 31 / 30 0 0 0
LUBBOCK 48 26 60 31 / 20 0 0 0
DENVER CITY 47 27 62 31 / 30 0 0 0
BROWNFIELD 46 26 61 32 / 30 0 0 0
CHILDRESS 53 25 56 29 / 20 0 0 0
SPUR 50 28 60 32 / 20 0 0 0
ASPERMONT 52 28 62 33 / 20 0 0 0
&&
.LUB WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY UNTIL 6 AM CST EARLY THIS MORNING FOR
TXZ039-040.
&&
$$
05/01
AREA FORECAST DISCUSSION
NWS BROWNSVILLE TX
1137 PM CST MON FEB 16 2015
.DISCUSSION...UPDATED FOR LATEST AVIATION DISCUSSION BELOW.
&&
.AVIATION...MVFR CIGS TO PREVAIL TONIGHT AS A SHARP SURFACE
INVERSION HAS BECOME ESTABLISHED IN WAKE OF THE FRONT. A WEAK
BUT PERSISTENT OVERRUNNING PATTERN WILL KEEP CIGS BETWEEN
1000-2500 FEET THROUGH TUESDAY MORNING. DRIER AIR EVENTUALLY
WORKS ITS WAY INTO THE VALLEY AS HIGH PRESSURE MOVES SOUTH
WEAKENING THE INVERSION AND ALLOWING FOR THE LOWER CLOUDS TO
BREAK AND RISE. IMPROVING FLYING CONDITIONS ARE ANTICIPATED
ESPECIALLY AFTER 3 PM. NORTH WINDS GUSTS AROUND 20 KTS TONIGHT
AND TUESDAY MORNING BEFORE BECOMING LESS FREQUENT.
&&
.PREV DISCUSSION... /ISSUED 1029 PM CST MON FEB 16 2015/
DISCUSSION...A FEW MINOR TWEAKS TO THE POP FORECAST OVERNIGHT.
SHALLOW MOISTURE AND WEAK OVERRUNNING WITH MINOR DISTURBANCES IN
THE MID LEVEL SOUTHWEST FLOW TO LIMIT RAINFALL OVERNIGHT. ECHOS
OUT WEST TO PRODUCE A FEW SPRINKLES WITH NOT MUCH FANFARE. BEST
POPS HAVE BEEN SHIFTED OUT WEST WITH SLIGHT CHANCES ELSEWHERE.
TEMPERATURES ARE IN THE BALL PARK AND WINDS CONTINUE TO STEADILY
DIMINISH.
PREV DISCUSSION... /ISSUED 545 PM CST MON FEB 16 2015/
DISCUSSION...UPDATED FOR LATEST AVIATION DISCUSSION BELOW.
AVIATION...THE COLD FRONT HAS PASSED THROUGH ALL TERMINALS AND
IS TRACKING SOUTH OF THE RIO GRANDE RIVER. IFR TO LOWER END MVFR
CEILING HAVE QUICKLY FILLED IN WAKE OF THE FRONT WITH NORTH WINDS
GUSTING 25 TO 30 KNOTS THROUGH AT LEAST 8 PM. THE HIGHER GUST TO
BECOME LESS FREQUENT WITH TIME WITH A STEADY NORTH WIND THE REST
OF THE NIGHT. CEILINGS TO RISE SLIGHTLY BUT REMAIN MAINLY ON THE
LOWER END OF MVFR UNTIL SUNRISE OR BY MID MORNING TUESDAY WHEN
THE MIGHT APPROACH VFR.
PREV DISCUSSION... /ISSUED 316 PM CST MON FEB 16 2015/
SHORT TERM /NOW THROUGH TUESDAY NIGHT/...A STRONG COLD FRONT
EXTENDING CURRENTLY FROM NEAR RIO GRANDE CITY TO NEAR BAFFIN BAY
WITH A PRE FRONTAL TROUGH AHEAD OF THE FRONT...ACROSS THE UPPER
PORTIONS OF THE RIO GRANDE VALLEY. WEST TO SOUTHWEST WINDS BETWEEN
2 TO 4K FEET MIXING DOWN TO THE SURFACE ALONG WITH FULL SUNSHINE HAS
ALLOWED TEMPERATURES TO SPIKE INTO THE LOW TO MID 80S ACROSS THE
VALLEY. BASED ON THE LATEST NAM/RAP AND HRRR DATA...THE STRONG FRONT
IS EXPECTED TO MOVE THROUGH MCALLEN AND HARLINGEN BETWEEN 4 AND 5
PM...BROWNSVILLE BETWEEN 5 AND 6 PM AND OFF THE LOWER TEXAS COAST
AROUND 7 PM. A DRASTIC CHANGE TO TEMPERATURES...BREEZY NORTH
WINDS...INCREASING LOW CLOUDINESS AND A POSSIBLE LIGHT SHOWER WILL
ACCOMPANY THE SHARP FROPA. TEMPERATURES WILL CONTINUE TO DROP
THROUGH THE EVENING WITH OVERNIGHT LOW TEMPERATURES IN THE 40S UNDER
MOSTLY CLOUDY SKIES. A MID TO UPPER LEVEL DISTURBANCE WILL MOVE
OVERHEAD TONIGHT. THIS FEATURE WILL SUPPORT ISOLATED TO SCATTERED
SHOWERS ACROSS THE REGION TONIGHT AND MAY LINGER ALONG THE COAST
INTO THE GULF WATERS TUESDAY MORNING.
SURFACE HIGH PRESSURE WILL BUILD ACROSS DEEP SOUTH TEXAS ON TUESDAY.
SKIES WILL GRADUALLY CLEAR BY TUESDAY AFTERNOON WITH TEMPERATURES
REMAINING WELL BELOW NORMAL. HIGH TEMPERATURES ON TUESDAY WILL BE IN
THE MID TO UPPER 50S WITH A FEW 60S POSSIBLE ACROSS THE WESTERN AREA
WITH MODERATE NORTH TO NORTHEAST WINDS. SURFACE HIGH PRESSURE
SETTLES ACROSS THE AREA TUESDAY NIGHT. CLEAR SKIES...DRY AIR AND
LIGHT WINDS WILL ALLOW FOR GOOD RADIATIONAL COOLING TUESDAY NIGHT.
OVERNIGHT LOW TEMPERATURES TUESDAY NIGHT EXPECTED TO FALL INTO THE
UPPER 30S ACROSS THE NORTHERN RANCHLANDS...LOWER 40S ACROSS THE RIO
GRANDE VALLEY AND THE MID 40S ALONG THE BEACHES.
LONG TERM /WEDNESDAY THROUGH MONDAY/...500 MB RIDGING WILL
BUILD OVER DEEP SOUTH TX STARTING WEDNESDAY CONTINUING INTO FRIDAY
WHICH WILL ALLOW THE 1000-500 MB THICKNESSES TO INCREASE WITH A
PERSISTENT S-SE SURFACE FLOW BRINGING IN STEADY WAA AT THE LOW
LEVELS. THIS WILL ALLOW TEMPS TO STEADILY INCREASE THROUGH THE END
OF THIS WEEK. AS THE WEEKEND APPROACHES THE 500 MB RIDGE WILL BE
ERODED STEADILY AS A SERIES OF STRONG SHORT WAVES CARVE OUT A
BROAD 500 MB TROUGH OVER THE NORTHERN HALF OF THE LOWER 48 STATES.
AS THIS 500 MB TROFFING DEEPENS A COLD FRONT WILL BE PUSHED
TOWARDS DEEP SOUTH TX ON SUN.
THE ECMWF AND GFS ARE IN GOOD AGREEMENT IN THE OVERALL PLACEMENT
OF THE 500 MB FEATURES THROUGH FRI. THE MODELS THEN START TO
DIVERGE STEADILY FROM SAT THROUGH MON WITH THE ECMWF DIGGING A
DEEPER 500 MB TROUGH AXIS OVER THE LOWER 48 STATES VERSUS THE GFS.
THE GFS KEEPS THE 500 MB TROUGH AXIS MORE ELONGATED FROM THE WEST
COAST UP THROUGH THE GREAT LAKES WHICH KEEPS THE COLD FRONT FROM
PUSHING THROUGH THE RGV.
MOISTURE ADVECTION AHEAD OF THIS NEXT POTENTIAL FROPA IS NOT THE
GREATEST IN THE WORLD SO WILL HOLD THE POPS AROUND 20 % LATE IN
THE FORECAST PERIOD UNTIL THE MODELS RESOLVE THEMSELVES A BIT
BETTER.
WILL LEAN MORE TOWARDS THE ECMWF SOLUTION THROUGH DAY 7 FOR TEMPS.
OVERALL CONFIDENCE IN THE FORECAST IS PRETTY GOOD THROUGH FRI THEN
STARTS TO DROP FOR THE SAT THROUGH MON PERIOD DUE TO THE ECMWF AND
GFS DIVERGENCE LATE IN THE PERIOD.
MARINE...NOW THROUGH TUESDAY NIGHT...LIGHT SOUTH TO SOUTHWEST WINDS
WILL CONTINUE ALONG THE LOWER TEXAS COASTAL FOR THE NEXT FEW HOURS.
A STRONG COLD FRONT WILL MOVE FROM NORTH TO SOUTH ACROSS THE MARINE
AREA. WINDS WILL QUICKLY SHIFT TO THE NORTH TO NORTHWEST WITH GUSTY
WINDS. A SMALL CRAFT ADVISORY IS IN EFFECT FOR ALL OF THE LOWER
TEXAS COASTAL WINDS DUE TO VERY STRONG WINDS WITH ROUGH SEAS ON THE
GULF. MARINE CONDITIONS GRADUALLY IMPROVE TUESDAY EVENING INTO
WEDNESDAY AS HIGH PRESSURE SETTLES ACROSS THE AREA.
WEDNESDAY THROUGH SATURDAY...A MODERATE TO STRONG S-SE WINDS WILL
PREVAIL IN THE LONGER RANGE MARINE FORECAST PERIOD AS BROAD
SURFACE RIDGING REMAINS IN PLACE OVER THE GULF OF MEX. THE PGF
TIGHTENS UP ENOUGH FROM LATE THURS THROUGH SATURDAY TO POSSIBLY
RESULT IN SOME SCA FOR THE GULF WATERS.
&&
.BRO WATCHES/WARNINGS/ADVISORIES...
TX...NONE.
GM...SMALL CRAFT ADVISORY FOR WINDS UNTIL 3 AM CST TUESDAY FOR GMZ130-
132-135.
SMALL CRAFT ADVISORY UNTIL 6 PM CST TUESDAY FOR GMZ150-155-170-
175.
&&
$$
THIS PRODUCT IS ALSO AVAILABLE ON THE WEB AT:
HTTP://WEATHER.GOV/RGV
67/61
AREA FORECAST DISCUSSION...UPDATED
NWS BROWNSVILLE TX
1029 PM CST MON FEB 16 2015
.DISCUSSION...A FEW MINOR TWEAKS TO THE POP FORECAST OVERNIGHT.
SHALLOW MOISTURE AND WEAK OVERRUNNING WITH MINOR DISTURBANCES IN
THE MID LEVEL SOUTHWEST FLOW TO LIMIT RAINFALL OVERNIGHT. ECHOS
OUT WEST TO PRODUCE A FEW SPRINKLES WITH NOT MUCH FANFARE. BEST
POPS HAVE BEEN SHIFTED OUT WEST WITH SLIGHT CHANCES ELSEWHERE.
TEMPERATURES ARE IN THE BALL PARK AND WINDS CONTINUE TO STEADILY
DIMINISH.
&&
.PREV DISCUSSION... /ISSUED 545 PM CST MON FEB 16 2015/
DISCUSSION...UPDATED FOR LATEST AVIATION DISCUSSION BELOW.
AVIATION...THE COLD FRONT HAS PASSED THROUGH ALL TERMINALS AND
IS TRACKING SOUTH OF THE RIO GRANDE RIVER. IFR TO LOWER END MVFR
CEILING HAVE QUICKLY FILLED IN WAKE OF THE FRONT WITH NORTH WINDS
GUSTING 25 TO 30 KNOTS THROUGH AT LEAST 8 PM. THE HIGHER GUST TO
BECOME LESS FREQUENT WITH TIME WITH A STEADY NORTH WIND THE REST
OF THE NIGHT. CEILINGS TO RISE SLIGHTLY BUT REMAIN MAINLY ON THE
LOWER END OF MVFR UNTIL SUNRISE OR BY MID MORNING TUESDAY WHEN
THE MIGHT APPROACH VFR.
PREV DISCUSSION... /ISSUED 316 PM CST MON FEB 16 2015/
SHORT TERM /NOW THROUGH TUESDAY NIGHT/...A STRONG COLD FRONT
EXTENDING CURRENTLY FROM NEAR RIO GRANDE CITY TO NEAR BAFFIN BAY
WITH A PRE FRONTAL TROUGH AHEAD OF THE FRONT...ACROSS THE UPPER
PORTIONS OF THE RIO GRANDE VALLEY. WEST TO SOUTHWEST WINDS BETWEEN
2 TO 4K FEET MIXING DOWN TO THE SURFACE ALONG WITH FULL SUNSHINE HAS
ALLOWED TEMPERATURES TO SPIKE INTO THE LOW TO MID 80S ACROSS THE
VALLEY. BASED ON THE LATEST NAM/RAP AND HRRR DATA...THE STRONG FRONT
IS EXPECTED TO MOVE THROUGH MCALLEN AND HARLINGEN BETWEEN 4 AND 5
PM...BROWNSVILLE BETWEEN 5 AND 6 PM AND OFF THE LOWER TEXAS COAST
AROUND 7 PM. A DRASTIC CHANGE TO TEMPERATURES...BREEZY NORTH
WINDS...INCREASING LOW CLOUDINESS AND A POSSIBLE LIGHT SHOWER WILL
ACCOMPANY THE SHARP FROPA. TEMPERATURES WILL CONTINUE TO DROP
THROUGH THE EVENING WITH OVERNIGHT LOW TEMPERATURES IN THE 40S UNDER
MOSTLY CLOUDY SKIES. A MID TO UPPER LEVEL DISTURBANCE WILL MOVE
OVERHEAD TONIGHT. THIS FEATURE WILL SUPPORT ISOLATED TO SCATTERED
SHOWERS ACROSS THE REGION TONIGHT AND MAY LINGER ALONG THE COAST
INTO THE GULF WATERS TUESDAY MORNING.
SURFACE HIGH PRESSURE WILL BUILD ACROSS DEEP SOUTH TEXAS ON TUESDAY.
SKIES WILL GRADUALLY CLEAR BY TUESDAY AFTERNOON WITH TEMPERATURES
REMAINING WELL BELOW NORMAL. HIGH TEMPERATURES ON TUESDAY WILL BE IN
THE MID TO UPPER 50S WITH A FEW 60S POSSIBLE ACROSS THE WESTERN AREA
WITH MODERATE NORTH TO NORTHEAST WINDS. SURFACE HIGH PRESSURE
SETTLES ACROSS THE AREA TUESDAY NIGHT. CLEAR SKIES...DRY AIR AND
LIGHT WINDS WILL ALLOW FOR GOOD RADIATIONAL COOLING TUESDAY NIGHT.
OVERNIGHT LOW TEMPERATURES TUESDAY NIGHT EXPECTED TO FALL INTO THE
UPPER 30S ACROSS THE NORTHERN RANCHLANDS...LOWER 40S ACROSS THE RIO
GRANDE VALLEY AND THE MID 40S ALONG THE BEACHES.
LONG TERM /WEDNESDAY THROUGH MONDAY/...500 MB RIDGING WILL
BUILD OVER DEEP SOUTH TX STARTING WEDNESDAY CONTINUING INTO FRIDAY
WHICH WILL ALLOW THE 1000-500 MB THICKNESSES TO INCREASE WITH A
PERSISTENT S-SE SURFACE FLOW BRINGING IN STEADY WAA AT THE LOW
LEVELS. THIS WILL ALLOW TEMPS TO STEADILY INCREASE THROUGH THE END
OF THIS WEEK. AS THE WEEKEND APPROACHES THE 500 MB RIDGE WILL BE
ERODED STEADILY AS A SERIES OF STRONG SHORT WAVES CARVE OUT A
BROAD 500 MB TROUGH OVER THE NORTHERN HALF OF THE LOWER 48 STATES.
AS THIS 500 MB TROFFING DEEPENS A COLD FRONT WILL BE PUSHED
TOWARDS DEEP SOUTH TX ON SUN.
THE ECMWF AND GFS ARE IN GOOD AGREEMENT IN THE OVERALL PLACEMENT
OF THE 500 MB FEATURES THROUGH FRI. THE MODELS THEN START TO
DIVERGE STEADILY FROM SAT THROUGH MON WITH THE ECMWF DIGGING A
DEEPER 500 MB TROUGH AXIS OVER THE LOWER 48 STATES VERSUS THE GFS.
THE GFS KEEPS THE 500 MB TROUGH AXIS MORE ELONGATED FROM THE WEST
COAST UP THROUGH THE GREAT LAKES WHICH KEEPS THE COLD FRONT FROM
PUSHING THROUGH THE RGV.
MOISTURE ADVECTION AHEAD OF THIS NEXT POTENTIAL FROPA IS NOT THE
GREATEST IN THE WORLD SO WILL HOLD THE POPS AROUND 20 % LATE IN
THE FORECAST PERIOD UNTIL THE MODELS RESOLVE THEMSELVES A BIT
BETTER.
WILL LEAN MORE TOWARDS THE ECMWF SOLUTION THROUGH DAY 7 FOR TEMPS.
OVERALL CONFIDENCE IN THE FORECAST IS PRETTY GOOD THROUGH FRI THEN
STARTS TO DROP FOR THE SAT THROUGH MON PERIOD DUE TO THE ECMWF AND
GFS DIVERGENCE LATE IN THE PERIOD.
MARINE...NOW THROUGH TUESDAY NIGHT...LIGHT SOUTH TO SOUTHWEST WINDS
WILL CONTINUE ALONG THE LOWER TEXAS COASTAL FOR THE NEXT FEW HOURS.
A STRONG COLD FRONT WILL MOVE FROM NORTH TO SOUTH ACROSS THE MARINE
AREA. WINDS WILL QUICKLY SHIFT TO THE NORTH TO NORTHWEST WITH GUSTY
WINDS. A SMALL CRAFT ADVISORY IS IN EFFECT FOR ALL OF THE LOWER
TEXAS COASTAL WINDS DUE TO VERY STRONG WINDS WITH ROUGH SEAS ON THE
GULF. MARINE CONDITIONS GRADUALLY IMPROVE TUESDAY EVENING INTO
WEDNESDAY AS HIGH PRESSURE SETTLES ACROSS THE AREA.
WEDNESDAY THROUGH SATURDAY...A MODERATE TO STRONG S-SE WINDS WILL
PREVAIL IN THE LONGER RANGE MARINE FORECAST PERIOD AS BROAD
SURFACE RIDGING REMAINS IN PLACE OVER THE GULF OF MEX. THE PGF
TIGHTENS UP ENOUGH FROM LATE THURS THROUGH SATURDAY TO POSSIBLY
RESULT IN SOME SCA FOR THE GULF WATERS.
&&
.PRELIMINARY POINT TEMPS/POPS...
BAYVIEW/PORT ISABEL 48 56 45 66 / 20 20 0 0
BROWNSVILLE 47 57 44 67 / 20 20 0 0
HARLINGEN 46 57 42 67 / 20 20 0 0
MCALLEN 47 60 42 68 / 20 10 0 0
RIO GRANDE CITY 47 60 41 69 / 30 10 0 0
SOUTH PADRE ISLAND 51 56 52 64 / 20 30 0 0
&&
.BRO WATCHES/WARNINGS/ADVISORIES...
TX...NONE.
GM...SMALL CRAFT ADVISORY FOR WINDS UNTIL 3 AM CST TUESDAY FOR GMZ130-
132-135.
SMALL CRAFT ADVISORY UNTIL 6 PM CST TUESDAY FOR GMZ150-155-170-
175.
&&
$$
THIS PRODUCT IS ALSO AVAILABLE ON THE WEB AT:
HTTP://WEATHER.GOV/RGV
59/68
AREA FORECAST DISCUSSION
NWS BLACKSBURG VA
1249 AM EST TUE FEB 17 2015
.SYNOPSIS...
A WINTER STORM WILL MOVE ACROSS THE MID-ATLANTIC REGION TONIGHT.
THIS STORM WILL PRODUCE HEAVY SNOW ACROSS THE VIRGINIA`S AND A
MIXTURE OF SNOW...SLEET...AND FREEZING RAIN ACROSS THE CAROLINAS.
THE STORM WILL MOVE EAST AND OFF THE COAST TUESDAY...FOLLOWED BY
THE PASSAGE OF AN ARCTIC COLD FRONT ON WEDNESDAY.
&&
.NEAR TERM /THROUGH TODAY/...
AS 1145 PM EST MONDAY...
MAIN SHORT WAVE AND UPPER JET SUPPORT WERE CROSSING THROUGH
SOUTHERN VIRGINIA AT 11PM. WESTERN EDGE OF THE MODERATE TO HEAVY
SNOW WAS ADVANCING EAST THROUGH THE FORECAST AREA. EXPECT THIS TO
CLEAR THE SOUTHEAST COUNTIES AROUND MIDNIGHT. LIGHT SNOW WILL END
FROM WEST TO EAST BETWEEN 08Z/3AM AND 12Z/7AM BASED ON LOCAL WRF
AND HRRR GUIDANCE.
00Z SOUNDING AT RNK HAD WARM NOSE OF -1.1C WHILE GSO SOUNDING
SHOWED A WARM NOSE AT 0C. GETTING NUMEROUS REPORTS OF SLEET FROM
WILKES COUNTY ACROSS THE NORTH CAROLINA FOOTHILLS AND PIEDMONT.
WITH THE BULK OF THE MODERATE TO HEAVY SNOW NOW MOVING
OUT...REMAINING SNOW ACCUMULATIONS THROUGH 12Z/7AM WILL BE IN THE
1 TO 3 INCH RANGE.
NO CHANGES ARE PLANNED TO THE WINTER STORM WARNINGS AT THIS TIME.
MODELS ARE IN VERY GOOD AGREEMENT WITH THE FORECAST TRACK OF THIS
STORM AND THE PLACEMENT OF THE HEAVIEST SNOW. SEE NO REASON STRAY
FROM GUIDANCE.
&&
.SHORT TERM /TONIGHT THROUGH THURSDAY NIGHT/...
AS OF 400 AM EST MONDAY...
WILL START TUESDAY NIGHT OFF WITH WINDS SHIFTING MORE SOUTHWESTERLY
AHEAD OF OUR NEXT ARCTIC COLD FRONT. OVERNIGHT LOW TEMPERATURES WILL
RANGE FROM THE LOW TEENS ACROSS THE MOUNTAINS...TO THE MID AND UPPER
TEENS ACROSS THE PIEDMONT. WIND SPEEDS WILL INCREASE TOWARD DAWN AS
THE PRESSURE GRADIENT TIGHTENS...WHICH WILL PUSH WIND CHILL
TEMPERATURES INTO THE LOW SINGLE DIGITS ACROSS THE MOUNTAINS...AND
BELOW ZERO IN A FEW SPOTS.
THE ARCTIC COLD FRONT WILL ARRIVE DURING LATE WEDNESDAY MORNING...
RESULTING IN ANOTHER RAPID DROP IN TEMPERATURES AND AN INCREASE IN
WIND SPEEDS...ALTHOUGH NOT A STRONG AS THOSE OBSERVED THIS PAST
WEEKEND. THAT STATED...WOULD NOT BE SURPRISED TO SEE 50 MPH GUSTS
ACROSS THE HIGHER RIDGES WEDNESDAY EVENING AND WEDNESDAY NIGHT. THE
FRONT WILL ALSO BRING WITH IT ANOTHER ROUND OF SNOW SHOWERS THAT
WILL AFFECT THE ENTIRE FORECAST REGION TO SOME DEGREE. ONE TO THREE
INCHES OF ADDITIONAL SNOWFALL CAN BE EXPECTED ALONG THE WEST FACING
SLOPES...WITH LOCALLY HIGHER AMOUNTS...WHILE A QUARTER TO HALF INCH
OF ADDITIONAL SNOW CAN BE EXPECTED FOR THE FOOTHILLS AND THE
PIEDMONT. THE VERY COLD AIR BUILDING IN BEHIND THE FRONT WILL ENSURE
A DRY POWDERY SNOW...WHICH WILL BLOW EASILY IN THE GUSTY WINDS. AS
SUCH...HAZARDOUS TRAVEL CONDITIONS CAN BE EXPECTED DUE TO DRIFTING
OF SNOW ON ROADWAYS AND OCCASIONAL WHITE OUT CONDITIONS.
&&
.LONG TERM /FRIDAY THROUGH MONDAY/...
AS OF 400 PM EST MONDAY...
WILL BE UPDATED BY 600 PM.
&&
.AVIATION /06Z TUESDAY THROUGH SATURDAY/...
AS OF 1245 AM EST TUESDAY...
HIGH CONFIDENCE FORECAST AS WINTER STORM WILL CONTINUE POOR
FLYING CONDITIONS WITH SNOW. MODERATE TO HEAVY SNOW HAS MOVED OUT
OF REGION. RADAR AND OBSERVATIONS AT 05Z INDICATED MVFR CEILINGS
AND A MIX OF LIGHT SNOW...SLEET AND FREEZING DRIZZLE AS FAR NORTH
AS KBCB...KROA AND KLYH. ANY ADDITIONAL SNOW AND SLEET
ACCUMULATION WILL BE ONE OR TWO INCHES. A LIGHT GLAZE OF ICE IS
POSSIBLE ON TOP OF THE SNOW AND SLEET.
THE PRECIPITATION WILL TAPER OFF FROM WEST TO EAT BETWEEN 09Z/4AM
AND 12Z/7AM. HOWEVER...CEILINGS WILL LOWER BACK TO IFR OR LIFR.
ONCE THE SURFACE LOW MOVES OFF THE VIRGINIA COAST...WINDS WILL
COME AROUND TO THE NORTHWEST. CEILINGS WILL BEGIN TO LIFT EAST OF
THE BLUE RIDGE BY LATE AFTERNOON. MODERATE CONFIDENCE THAT
KROA/KDAN AND KLYH WILL IMPROVE TO VFR BY 00Z/7PM TUESDAY.
AN ARCTIC COLD FRONT COMES THROUGH WEDNESDAY WITH STRONG
NORTHWEST WINDS WEDNESDAY INTO THURSDAY. MOUNTAIN SNOW SHOWERS
WITH MVFR CEILINGS AND VISIBILITIES ARE LIKELY WEDNESDAY AND
WEDNESDAYS NIGHT AND WILL BEGIN TO DISSIPATE ON THURSDAY. WITH
STRONG DOWNSLOPE WINDS...CONDITIONS FARTHER EAST OF THE BLUE
RIDGE WILL BE VFR.
THE NEXT VFR DAY IN THE MOUNTAINS WILL NOT BE UNTIL FRIDAY.
ANOTHER FRONT APPROACHES FROM THE WEST ON SATURDAY.
&&
.RNK WATCHES/WARNINGS/ADVISORIES...
VA...WINTER STORM WARNING UNTIL NOON EST TODAY FOR VAZ007-009>020-
022>024-032>035-043>047-058-059.
NC...WINTER STORM WARNING UNTIL NOON EST TODAY FOR NCZ001>006-
018>020.
WV...WINTER STORM WARNING UNTIL NOON EST TODAY FOR WVZ042>044-507-
508.
&&
$$
SYNOPSIS...AMS/PM
NEAR TERM...AMS/PM
SHORT TERM...NF
LONG TERM...NF
AVIATION...AMS/KK
AREA FORECAST DISCUSSION
NWS BLACKSBURG VA
1152 PM EST MON FEB 16 2015
.SYNOPSIS...
A WINTER STORM WILL MOVE ACROSS THE MID-ATLANTIC REGION TONIGHT.
THIS STORM WILL PRODUCE HEAVY SNOW ACROSS THE VIRGINIA`S AND A
MIXTURE OF SNOW...SLEET...AND FREEZING RAIN ACROSS THE CAROLINAS.
THE STORM WILL MOVE EAST AND OFF THE COAST TUESDAY...FOLLOWED BY
THE PASSAGE OF AN ARCTIC COLD FRONT ON WEDNESDAY.
&&
.NEAR TERM /THROUGH TUESDAY/...
AS 1145 PM EST MONDAY...
MAIN SHORT WAVE AND UPPER JET SUPPORT WERE CROSSING THROUGH
SOUTHERN VIRGINIA AT 11PM. WESTERN EDGE OF THE MODERATE TO HEAVY
SNOW WAS ADVANCING EAST THROUGH THE FORECAST AREA. EXPECT THIS TO
CLEAR THE SOUTHEAST COUNTIES AROUND MIDNIGHT. LIGHT SNOW WILL END
FROM WEST TO EAST BETWEEN 08Z/3AM AND 12Z/7AM BASED ON LOCAL WRF
AND HRRR GUIDANCE.
00Z SOUNDING AT RNK HAD WARM NOSE OF -1.1C WHILE GSO SOUNDING
SHOWED A WARM NOSE AT 0C. GETTING NUMEROUS REPORTS OF SLEET FROM
WILKES COUNTY ACROSS THE NORTH CAROLINA FOOTHILLS AND PIEDMONT.
WITH THE BULK OF THE MODERATE TO HEAVY SNOW NOW MOVING
OUT...REMAINING SNOW ACCUMULATIONS THROUGH 12Z/7AM WILL BE IN THE
1 TO 3 INCH RANGE.
NO CHANGES ARE PLANNED TO THE WINTER STORM WARNINGS AT THIS TIME.
MODELS ARE IN VERY GOOD AGREEMENT WITH THE FORECAST TRACK OF THIS
STORM AND THE PLACEMENT OF THE HEAVIEST SNOW. SEE NO REASON STRAY
FROM GUIDANCE.
&&
.SHORT TERM /TUESDAY NIGHT THROUGH THURSDAY NIGHT/...
AS OF 400 AM EST MONDAY...
WILL START TUESDAY NIGHT OFF WITH WINDS SHIFTING MORE SOUTHWESTERLY
AHEAD OF OUR NEXT ARCTIC COLD FRONT. OVERNIGHT LOW TEMPERATURES WILL
RANGE FROM THE LOW TEENS ACROSS THE MOUNTAINS...TO THE MID AND UPPER
TEENS ACROSS THE PIEDMONT. WIND SPEEDS WILL INCREASE TOWARD DAWN AS
THE PRESSURE GRADIENT TIGHTENS...WHICH WILL PUSH WIND CHILL
TEMPERATURES INTO THE LOW SINGLE DIGITS ACROSS THE MOUNTAINS...AND
BELOW ZERO IN A FEW SPOTS.
THE ARCTIC COLD FRONT WILL ARRIVE DURING LATE WEDNESDAY MORNING...
RESULTING IN ANOTHER RAPID DROP IN TEMPERATURES AND AN INCREASE IN
WIND SPEEDS...ALTHOUGH NOT A STRONG AS THOSE OBSERVED THIS PAST
WEEKEND. THAT STATED...WOULD NOT BE SURPRISED TO SEE 50 MPH GUSTS
ACROSS THE HIGHER RIDGES WEDNESDAY EVENING AND WEDNESDAY NIGHT. THE
FRONT WILL ALSO BRING WITH IT ANOTHER ROUND OF SNOW SHOWERS THAT
WILL AFFECT THE ENTIRE FORECAST REGION TO SOME DEGREE. ONE TO THREE
INCHES OF ADDITIONAL SNOWFALL CAN BE EXPECTED ALONG THE WEST FACING
SLOPES...WITH LOCALLY HIGHER AMOUNTS...WHILE A QUARTER TO HALF INCH
OF ADDITIONAL SNOW CAN BE EXPECTED FOR THE FOOTHILLS AND THE
PIEDMONT. THE VERY COLD AIR BUILDING IN BEHIND THE FRONT WILL ENSURE
A DRY POWDERY SNOW...WHICH WILL BLOW EASILY IN THE GUSTY WINDS. AS
SUCH...HAZARDOUS TRAVEL CONDITIONS CAN BE EXPECTED DUE TO DRIFTING
OF SNOW ON ROADWAYS AND OCCASIONAL WHITE OUT CONDITIONS.
&&
.LONG TERM /FRIDAY THROUGH MONDAY/...
AS OF 400 PM EST MONDAY...
WILL BE UPDATED BY 600 PM.
&&
.AVIATION /06Z TUESDAY THROUGH SATURDAY/...
AS OF 700 PM EST MONDAY...
HIGH CONFIDENCE FORECAST AS WINTER STORM WILL CONTINUE POOR
FLYING CONDITIONS WITH SNOW. IFR AND LIFR CONDITIONS WITH MODERATE
TO HEAVY SNOW WILL CONTINUE ACROSS THE REGION THROUGH 09Z/4AM. THE
SNOW WILL TAPER OFF FROM WEST TO EAT BETWEEN 09Z/4AM AND 12Z/7AM.
HOWEVER...EVEN THOUGH THE SNOW WILL END CEILINGS WILL REMAIN IFR
OR LIFR. ONCE THE SURFACE LOW MOVES OFF THE VIRGINIA COAST...WINDS
WILL COME AROUND TO THE NORTHWEST AND CEILINGS WILL BEGIN TO LIFT
EAT OF THE BLUE RIDGE. MODERATE CONFIDENCE THAT KROA/KDAN AND KLYH
WILL IMPROVE TO MVFR AFTER 18Z/1PM.
AN ARCTIC COLD FRONT COMES THROUGH TUESDAY NIGHT WITH STRONG
NORTHWEST WIND FOR BOTH WEDNESDAY AND THURSDAY. MOUNTAIN SNOW
SHOWERS AND AT LEAST MVFR CIGS WILL LINGER ACROSS THE MOUNTAINS
THROUGH THURSDAY. THE NEXT COMPLETELY CLEAR VFR WILL NOT BE UNTIL
FRIDAY IN THE MOUNTAINS. ANOTHER FRONTAL SYSTEM APPROACHES FROM
THE WEST SATURDAY INTO SUNDAY.
&&
.RNK WATCHES/WARNINGS/ADVISORIES...
VA...WINTER STORM WARNING UNTIL NOON EST TUESDAY FOR VAZ007-009>020-
022>024-032>035-043>047-058-059.
NC...WINTER STORM WARNING UNTIL NOON EST TUESDAY FOR NCZ001>006-
018>020.
WV...WINTER STORM WARNING UNTIL NOON EST TUESDAY FOR WVZ042>044-507-
508.
&&
$$
SYNOPSIS...AMS/PM
NEAR TERM...AMS/PM
SHORT TERM...NF
LONG TERM...NF
AVIATION...AMS/KK
AREA FORECAST DISCUSSION
NWS MILWAUKEE/SULLIVAN WI
310 PM CST TUE FEB 17 2015
.TONIGHT AND WEDNESDAY...CONFIDENCE - HIGH.
A POTENT 500MB SHORTWAVE TROUGH WILL SWING THROUGH THE REGION LATER
TONIGHT...WITH THE VORTICITY MAXIMA JUST TO OUR SOUTHWEST. THIS
SYSTEM WILL BE COINCIDENT WITH DECENT LOW LEVEL MOISTURE ADVECTION
AND GOOD 850MB COLD AIR ADVECTION. RAP BUFKIT SOUNDINGS INDICATE LOW
LEVEL LAPSE RATES WILL STEEPEN NEARLY DRY ADIABATICALLY THIS
EVENING. WEAK ISENTROPIC OMEGA WILL LIMIT SNOW AMOUNTS TONIGHT TO
BETWEEN A FEW TENTHS UP TO A HALF INCH ACROSS THE CWA.
THE BIG STORY WILL BE THE SINKING TEMPERATURES. 850MB TEMPERATURES
WILL REACH NEAR -28C OVER THE WESTERN HALF OF OUR CWA BY 18Z
WEDNESDAY. GUSTY NORTHWEST WINDS WILL KEEP WIND CHILLS DOWN...WITH
VALUES NEAR -20 FOR OUR FAR WESTERN TIER OF COUNTIES. WITH THE
INCREASE IN WIND SPEEDS AND GOOD COLD AIR ADVECTION...ISSUED A WIND
CHILL ADVISORY FOR SAUK...IOWA...AND LAFAYETTE COUNTIES BETWEEN 9Z
TO 16Z WED. TEMPERATURES WILL STAY COLD FOR WEDNESDAY WITH HIGHS
REACHING ONLY INTO THE SINGLE DIGITS ABOVE ZERO.
.WEDNESDAY NIGHT THROUGH FRIDAY...CONFIDENCE - HIGH.
ARCTIC COLD AIR WILL REMAIN ENTRENCHED OVER THE REGION THROUGH
THURSDAY NIGHT. 925H TEMPS FALL TO AROUND -25C WED NGT. HOWEVER
MIXY BOUNDARY LAYER AND POSSIBLE SOME LINGERING STRATUS WILL PREVENT
TEMPERATURE FREE FALL OVERNIGHT. NEVER THE LESS...STILL EXPECT
OVERNIGHT LOWS TO DIP TO BETWEEN -5 AND -12 CAUSING WIND CHILLS TO
DROP TO BETWEEN 20 AND 30 BELOW. A WIND CHILL ADVISORY WILL LIKELY
BE ISSUED ON WEDNESDAY FOR THIS PERIOD.
AN EVEN COLDER NIGHT LIES AHEAD FOR THURSDAY NIGHT AS LESS WIND AND
CLOUDS ARE EXPECTED. OVERNIGHT LOWS MAY DIP TO AS COLD AS -16 IN
LOW AREAS OF THE EASTERN CWA AWAY FROM THE SHORE. MORE QUESTIONABLE
HOWEVER WHETHER A WIND CHILL ADVISORY WILL BE NEEDED AS HIGH
PRESSURE RIDGE PASSING ACROSS SRN WI WILL RESULT IN DECOUPLING AND
LIGHT SFC WINDS OVERNIGHT.
CLOUDS WILL ALSO BEGIN TO INCREASE LATE IN THE NIGHT DUE TO UPSTREAM
STRONG WARM AIR ADVECTION. WEAK LAYER Q-VECTOR CONVERGENCE CLIPS
SRN WI WITH BETTER FORCING REMAINING TO THE NORTH. NEVER THE
LESS...WITH COLD DOME IN PLACE AND VIGOROUS WARM AIR
ADVECTION...WOULD NOT BE SURPRISED TO SEE MORE WIDESPREAD -SN
OVERSPREAD SRN WI ON FRI. HOWEVER FOR NOW DUE TO UNCERTAINTY WRT
STRENGTH OF LIFT AND COLUMN MOISTURE...WL KEEP POPS IN THE CHANCE
CATEGORY FOR NOW.
.FRIDAY NIGHT THROUGH SATURDAY NIGHT...CONFIDENCE - MEDIUM.
SLOWER EASTWARD PROGRESS OF SHORT WAVE TROF ACROSS WI FRIDAY NIGHT
SO WL CONTINUE SMALL POPS FOR -SN AS COLUMN MOISTURE EXTENDS TO
ABOUT 10K FT. TEMPORARY ZONAL TO SOUTHWEST FLOW ALOFT EARLY IN THE
WEEKEND WILL ALLOW AREA OF STRENGTHENING LOW PRESSURE ALONG
BAROCLINIC ZONE TO MOVE FROM THE SOUTHERN PLAINS INTO THE TN AND OH
VALLEY REGION ON SAT. ECMWF HAS BEEN TRENDING FARTHER SOUTH WITH
THE AFFECTS FROM THIS SYSTEM WHILE THE GFS HAS BEEN EDGING FARTHER
NORTH. ECMWF AND GFS CONVERGING ON SIMILAR SOLUTION WHICH KEEPS
SNOW SHIELD FROM THIS SYSTEM SOUTH OF SRN WI...MORE IN LINE WITH
LATEST CMC. WINDS MAY BRIEFLY TURN TO THE NORTHEAST AFTER TROUGH
PASSAGE FRIDAY NIGHT WHICH MAY BRING SOME LIGHT LAKE EFFECT TO THE
SOUTHEAST.
.SUNDAY THROUGH TUESDAY...CONFIDENCE - MEDIUM.
SHARPENING SHORT-WAVE TROF OVER ERN CONUS ASSOCIATED WITH ABOVE
SYSTEM WILL RESULT IN NORTHWEST STEERING FLOW AND COLDER TEMPS
RETURNING FOR SUNDAY AND LASTING INTO THE FIRST DAYS OF THE WEEK OF
THE 23RD. BOTH ECMWF AND GFS SHOW VIGOROUS SHORT WAVE TROF MOVING
SOUTHEAST AND AFFECTING THE WESTERN GTLAKES IN THE MON NGT/TUE
PERIOD. TEMPERATURES EARLY NEXT WEEK DO NOT LOOK TO BE AS COLD AS
WHAT IS EXPECTED THE NEXT SEVERAL DAYS...HOWEVER WILL REMAIN BELOW
NORMAL FOR LATE FEBRUARY.
&&
.AVIATION/00Z TAFS/...
500MB SHORTWAVE TROUGH WILL MOVE THROUGH THE REGION LATER
TONIGHT...SPARKING CHANCES OF LIGHT SNOW. A QUICK BURST OF MODERATE
SNOW IS POSSIBLE DUE TO THE STRENGTH OF THE POSITIVE VORTICITY
ADVECTION ASSOCIATED WITH THIS SHORTWAVE. IN GENERAL...VFR
CONDITIONS WILL PERSIST UNTIL THE LATE EVENING HOURS WHEN THE
SHORTWAVE TROUGH MOVES IN ABOUT 03Z TONIGHT. MVFR CONDITIONS WILL
BECOME MORE COMMON AS LIGHT SNOW DEVELOPS. WINDS WILL STAY FROM THE
NORTHWEST THROUGH THE EVENING AND OVERNIGHT HOURS. GUSTY WINDS OF UP
TO 25KTS ARE POSSIBLE TOMORROW AFTERNOON AS THE PRESSURE GRADIENT
TIGHTENS.
&&
.MARINE...
THE POTENTIAL FOR HIGHER WAVES ALONG THE NEARSHORE WILL INCREASE DUE
TO STRENGTHENING NORTHWEST WINDS...WITH GUSTS UP TO 25KTS DURING THE
DAY WEDNESDAY...ALONG WITH SOME BREAKS IN THE ICE ALONG THE LAKE MI
SHORE. DECIDED TO ISSUE A SMALL CRAFT ADVISORY IN EFFECT FROM 15Z
WED TO 00Z THURS DUE TO THE INCREASE IN WINDS. SOME LIGHT SNOW IS
ALSO A POTENTIAL LATER TONIGHT.
&&
.MKX WATCHES/WARNINGS/ADVISORIES...
WI...WIND CHILL ADVISORY WIZ056-062-067 FROM 09Z/18 TO 15Z/18.
LM...SMALL CRAFT ADVISORY FROM 15Z/18 TO 00Z/19 LMZ643>646.
$$
TONIGHT AND WEDNESDAY/AVIATION/MARINE....JTS
WEDNESDAY NIGHT THROUGH TUESDAY...MBK
AREA FORECAST DISCUSSION
NWS CHEYENNE WY
426 AM MST TUE FEB 17 2015
.SHORT TERM...(TODAY THROUGH THURSDAY)
ISSUED AT 200 AM MST TUE FEB 17 2015
THE MAIN FORECAST CONCERN OVER THE SHORT TERM WILL PRIMARILY BE IN
THE FIRST 24 HOURS DUE TO LOCALLY HEAVY SNOW SHOWERS MOVING SOUTH
ACROSS THE AREA EARLY THIS MORNING. THE NEXT WEAK UPPER LEVEL
SHORTWAVE IS NOW PUSHING INTO EASTERN WYOMING AND THE WESTERN
DAKOTAS AS A STRONG 150KT JET MAX MOVES SOUTHWARD INTO THE HIGH
PLAINS. LOW TO MIDLEVEL INSTABILITY DUE TO STEEP LAPSE RATES
BETWEEN 800MB TO 600MB WILL SUPPORT BANDED SNOWFALL THROUGH TODAY
AS ALREADY SEEN ON CURRENT KCYS RADAR LOOP. RADAR SHOWS A BAND OF
LOCALLY HEAVY SNOWFALL STRETCHING FROM DOUGLAS SOUTHEAST TOWARDS
THE CHEYENNE RIDGE SOUTH OF TORRINGTON...WHICH IS A BIT FURTHER
SOUTH THAN EXPECTED. THANKFULLY...THESE SHOWERS CONTAIN
RELATIVELY NARROW BANDS OF LOCALLY HEAVY SNOWFALL AND ARE MOVING
RATHER QUICK ACROSS THE AREA. THAT MAY CHANGE THIS MORNING HOWEVER
AS MODELS SHOW SOME ENHANCED LIFT IN THE VICINITY OF THE BLACK
HILLS AND PORTIONS OF FAR EASTERN WYOMING AND NORTHERN NEBRASKA
PANHANDLE. THIS AREA IS ALSO NEAR THE LEFT EXIT REGION OF THE
JET...SO KEPT POP ON THE HIGH SIDE NORTH OF THE PLATTE RIVER
VALLEY THIS MORNING. HOWEVER...HAVE TO QUESTION WHETHER THE BLACK
HILLS AND THE NORTHERLY WINDS ARE RESULTING IN SOME SNOW SHADOWING
EFFECT ACROSS THE FAR NORTHERN ZONES. EITHER WAY...SNOWFALL
AMOUNTS WILL BE TRICKY DUE TO THE CONVECTIVE BANDING...BUT CAN NOT
RULE OUT A QUICK 1 TO 2 INCHES OF SNOW ACROSS THE HIGH PLAINS.
THIS THREAT WILL SHIFT EAST THROUGH THE DAY AS THE JET AXIS SHIFTS
EASTWARD AS WELL. ON THE WESTERN HALF OF THE JET...DRIER AIR ALOFT
WILL BEGIN TO ENTER THE AREA AND DESCENT DOWN TO NEAR
500MB...GREATLY LOWERING THE POTENTIAL OF WIDESPREAD SNOW SHOWERS
OVER MOST OF SOUTHEAST WYOMING BY LATE THIS AFTERNOON. DUE TO THE
STEEP LAPSE RATES ACROSS THE AREA AND LLVL COLD AIR
ADVECTION...WINDS WILL ALSO BE AN ISSUE. KEPT THE WIND ADVISORY
OUT FOR THE SOUTHERN NE PANHANDLE TODAY FOR SUSTAINED WIND SPEEDS
BETWEEN 30 TO 35 MPH AND GUSTS AROUND 45 MPH. WILL ALSO NEED TO
MONITOR THE POTENTIAL FOR BLOWING SNOW IN AREAS THAT RECEIVED A
FEW INCHES OF SNOW ACCUMULATION DUE TO THE LOCALLY HEAVY SNOWFALL.
HOWEVER...THE AREA MIGHT NOT BE LARGE ENOUGH TO SUPPORT AN
ADVISORY. WILL CONTINUE TO MONITOR WEBCAMS AND REPORTS ACROSS THE
AREA IN THE EVENT AN ADVISORY FOR BLOWING SNOW AND REDUCED
VISIBILITIES IS NEEDED.
BY LATE THIS AFTERNOON AND INTO THIS EVENING...LAPSE RATES WILL
DECREASE FROM WEST TO EAST AS SNOW SHOWERS WILL TAPER TO ISOLATED
FLURRIES ACROSS THE HIGH PLAINS. CLOUDS WILL REMAIN OVER THE AREA
DUE TO THE VIGOROUS JET STREAM AND PLENTIFUL MIDLEVEL MOISTURE.
HOWEVER...DO NOT EXPECT MUCH IN THE WAY OF PRECIP TUESDAY NIGHT
SINCE MODEL SOUNDINGS SHOW A DEEP DRY LAYER ALOFT MOVING INTO THE
AREA.
FOR WEDNESDAY AND THURSDAY...MODELS SHOW THE STRONG RIDGE AXIS
ALONG THE WEST COAST WEAKENING AND FLATTENING OUT AS IT MOVES
EASTWARD INTO THE ROCKY MOUNTAINS...MAINLY DUE TO THE STRENGTH OF
THE ARCTIC AIRMASS IMPACTING THE EASTERN TWO THIRDS OF THE
COUNTRY. TEMPERATURES WILL RETURN TO AROUND NORMAL FOR THIS TIME
OF THE YEAR DUE TO SOME DOWNSLOPE FLOW WITH HIGHS IN THE MID 30S
TO MID 40S...WARMEST OVER THE SOUTHEAST WYOMING HIGH PLAINS AND
THE SOUTHERN NEBRASKA PANHANDLE. THE MID TO UPPER LEVEL FLOW WILL
BACK AND BECOME MORE WESTERLY ON THURSDAY AHEAD OF THE NEXT STORM
SYSTEM...WHICH WILL ALLOW TEMPERATURES TO INCREASE INTO THE UPPER
40S TO UPPER 50S ACROSS MOST OF THE FORECAST AREA. WILL HAVE TO
MONITOR WINDS ACROSS SOUTHEAST WYOMING FOR THURSDAY MORNING.
MODELS DO INDICATE THAT THE WIND PRONE AREAS MAY GET CLOSE TO HIGH
WIND CRITERIA. FOR NOW...INCREASED WINDS BETWEEN 30 TO 40 MPH
SUSTAINED WITH GUSTS AROUND 55 MPH. THE 850 TO 700MB GRADIENT DOES
INCREASE TO AROUND 55 DM DURING THIS TIME PERIOD...AND WILL SEE IF
FUTURE MODEL RUNS CONTINUE TO TREND HIGHER.
.LONG TERM...(THURSDAY NIGHT THROUGH MONDAY)
ISSUED AT 300 AM MST TUE FEB 17 2015
UNSETTLED WEATHER IN THE EXTENDED WITH MOST AREAS SEEING SNOW AT
SOME POINT THROUGH THE WEEKEND.
GOOD AGREEMENT BETWEEN THE GFS AND ECMWF BRINGING NEXT SHORTWAVE
INTO SOUTHEAST WYOMING FRIDAY AFTERNOON. FRONT SAGS TO THE
COLORADO/WYOMING BORDER FRIDAY AFTERNOON WITH WIDESPREAD RAIN
TURNING QUICKLY TO SNOW FRIDAY EVENING.
REALLY NEED TO WATCHING THIS FRONT AS IT STALLS OVER CENTRAL
COLORADO. 60-70 MILES FURTHER NORTH AND SOUTHERN WYOMING COULD BE
IN FOR A MAJOR WINTER EVENT. RIGHT NOW THOUGH...BEST CHANCES LOOK
TO BE FRIDAY NIGHT INTO SATURDAY MORNING. BOTH GFS AND ECMWF IN
AGREEMENT HOLDING ONTO SOME LIGHT QPF OVER OUR SOUTHERN BORDER
THROUGH THE WEEKEND...SO KEPT SOME LOW CHANCE POPS GOING THROUGH
SUNDAY.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z WEDNESDAY MORNING)
ISSUED AT 423 AM MST TUE FEB 17 2015
LATEST HRRR GUIDANCE USED FOR THE 12Z TAF SUITE. SHOWING SOME
NBANDS OF SNOW DEVELOPING OUT IN THE PANHANDLE THIS MORNING THAT
COULD PRODUCE SOME TEMPO CONDITIONS. BEST LOCATION LOOKS TO BE
KBFF AND KSNY IN THE SOUTHERN PANHANDLE. WINDS WILL BE ANOTHER
ISSUE TODAY AS MOST AIRPORTS WILL SEE SOME PRETTY STRONG NORTHWEST
WINDS. WINDS SHOULD DECREASE TOWARDS SUNSET TODAY.
&&
.FIRE WEATHER...
ISSUED AT 130 AM MST TUE FEB 17 2015
NO FIRE WEATHER CONCERNS THROUGH THIS WEEK. TEMPERATURES WILL
CONTINUE TO BE BELOW NORMAL THROUGH TUESDAY BEFORE THEY MODERATE
SOME ON WEDNESDAY AND THURSDAY. MINIMUM AFTERNOON HUMIDITY VALUES
WILL BE ABOVE 3O PERCENT. A STRONG COLD FRONT WILL PUSH SOUTHWARD
ACROSS THE AREA BRINGING A MODIFIED ARCTIC AIRMASS IN ADDITION TO
WIDESPREAD SNOWFALL BY NEXT WEEKEND.
&&
.CYS WATCHES/WARNINGS/ADVISORIES...
WY...NONE.
NE...WIND ADVISORY FROM 8 AM THIS MORNING TO 4 PM MST THIS AFTERNOON
FOR NEZ019>021-054-055.
&&
$$
SHORT TERM...TJT
LONG TERM...GCC
AVIATION...GCC
FIRE WEATHER...TJT
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 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 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 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...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 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 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