Forecast Discussions mentioning any of
"HRRR" "RAP" "RR" "RUC13" "RUC" received at GSD on 03/21/13
AREA FORECAST DISCUSSION
NWS SAN FRANCISCO BAY AREA
1057 PM PDT MON MAR 18 2013
.DISCUSSION...AS OF 9:00 PM PDT MONDAY...A SIGNIFICANT CHANGE
IN THE WEATHER PATTERN IS DEVELOPING TONIGHT WITH WARM FRONTAL
PROCESSES PRIMING THE ATMOSPHERE FOR THE INCOMING RAIN. DEW POINTS
ARE RISING...THE 00Z SOUNDING SHOWS A MOISTENING ATMOSPHERE AND
THE AMSU TPW SHOWS 0.75 TO 0.83 INCHES OF PRECIPITABLE WATER JUST
OFF THE NORTHERN AND CENTRAL CALIFORNIA COAST.
LOW CONFIDENCE IN THE CURRENT MODEL SOLUTIONS AS THEY ARE NOT
MATCHING UP TO WHAT IS CURRENTLY BEING OBSERVED. DOPPLER RADAR IS
CURRENTLY PICKING UP RETURNS OFF THE SONOMA AND MARIN COUNTY
COASTS WHICH WAS NOT DEPICTED BY THE GFS...NAM OR EURO. THE MOST
CURRENT HIGH RESOLUTION MODEL PRESENTLY AVAILABLE TO US...THE
RAP...DEPICT AN AREA OF MOISTURE APPROACHING THE COAST THIS
EVENING AND INTO TONIGHT. HOWEVER THE MOISTURE GRADUALLY
DISSIPATING AS IT NEARS THE COAST OVERNIGHT. THE RAP SHOWS LIGHT
PRECIP POSSIBLE OVER THE NORTHERN BORDER OF SONOMA COUNTY. WOULD
NOT RULE IT OUT AT THIS POINT. WILL NEED TO CLOSELY MONITOR THE
EVOLUTION OF THE APPROACHING LOW AND ASSOCIATED COLD FRONT
OVERNIGHT AND MAY NEED TO OVERHAUL THE FORECAST.
WILL HOLD OFF ON MAKING ANY SIGNIFICANT CHANGES TO THE FORECAST AND
WILL CONTINUE TO MONITOR.
FROM PREVIOUS DISCUSSION...HIGH CLOUDS CONTINUE TO STREAM
OVERHEAD AS MID/UPPER LEVEL MOISTURE CONTINUES TO FLOW THROUGH THE
"DIRTY RIDGE". WATER VAPOR IMAGERY IS INDC TWO SYSTEMS THAT WILL
HAVE AN EFFECT ON THE DISTRICTS WEATHER THE NEXT COUPLE OF
DAYS...ONE SYSTEM IS CENTERED NEAR 37/147 AND THE OTHER ONE IS
NEAR 57/150. THE SOUTHERN SYSTEM IS ENTRAINING SUBTROPICAL
MOISTURE WITH THE BLENDED AMSU SSM/I DATA INDC AS MUCH AS 1.8
INCHES OF TPW NEAR 26/142.
MODELS HAVE TRENDED SLOWER WITH THESE SYSTEMS AS WELL AS KEEPING
THEM OUT OF PHASE. THE NORTHERN SYSTEM WILL MOVE INTO THE PACIFIC
NORTHWEST WHEREAS THE SOUTHERN SYSTEM WILL WEAKEN AS IT MOVES TO
THE COAST. SINCE THE BEST DYNAMICS WILL BE WELL TO THE NORTH
OROGRAPHICS WILL BE THE MAIN LIFTING MECHANISM FOR RAIN. AS OF
NOW...IT LOOKS LIKE LIGHT RAIN WILL DEVELOP IN THE NORTH BAY
TUESDAY AFTN...SPREADING SOUTH TUESDAY NIGHT INTO WEDNESDAY. POST
FRONTAL SHOWERS WILL CONTINUE WEDNESDAY AFTN AND END EARLY
WEDNESDAY EVENING. RAINFALL TOTALS WILL BE LIGHT ACROSS THE
DISTRICT...WITH SOME LOCATIONS IN INTERIOR MONTEREY AND SAN BENITO
COUNTIES POSSIBLY NOT SEEING ANY RAIN AT ALL. THE WETTEST
LOCATIONS...IN THE NORTH BAY MOUNTAINS COULD GET AS MUCH AS 0.75
INCHES TOTAL...NOT VERY SIGNIFICANT. VALLEY LOCATIONS WILL GET
LESS THAN 0.50 INCHES OF RAIN TOTAL. BASICALLY...THIS WILL BE A
HIGH POP LOW QPF EVENT.
RIDGING WILL BUILD IN RAPIDLY THURSDAY...AND CONTINUING RIGHT INTO
THE EARLY PORTIONS OF NEXT WEEK. THIS WILL RESULT IN DRY WEATHER
WITH ABOVE NORMAL TEMPERATURES.
&&
.AVIATION...AS OF 11:00 PM PDT MONDAY...STORM SYSTEM STILL ON
TRACK TO IMPACT TERMINALS TOMORROW AFTERNOON THROUGH EARLY
WEDNESDAY MORNING. RADAR DOES SHOW SOME LIGHT RETURN RIGHT NOW
AROUND THE COAST SO A SPRINKLE COULD HIT OVERNIGHT. SOME LOW CIGS
DID BRIEFLY COME IN EARLIER, BUT THOSE ARE NOW GONE WITH VFR
ACROSS THE BOARD. POSSIBLE LOW CIGS COULD COME IN AGAIN AHEAD OF
THE RAIN...ESPECIALLY NEAR THE COAST. GUSTY WINDS DO NOT LOOK
LIKELY WITH THE FRONTAL PASSAGE ON TUESDAY. MODERATE CONFIDENCE.
VICINITY OF KSFO....VFR THROUGH THE NIGHT TONIGHT WITH RAIN
EXPECTED TO START TUESDAY AFTERNOON. WINDS SHOULD STAY UNDER 12 KT.
KSFO BRIDGE APPROACH...SIMILAR TO KSFO.
MONTEREY BAY AREA TERMINALS...TRICKY FOR MONTEREY BAY REGION
OVERNIGHT AS LOW CLOUDS BRIEFLY CAME IN BUT HAVE SKIES HAVE GONE
BACK TO VFR. MORE LOW CLOUDS COULD ROLL IN TONIGHT ALTHOUGH WILL
KEEP VFR GOING. RAIN WON`T HIT UNTIL TUESDAY EVENING. WINDS WILL
STAY UNDER 12 KT. LOW TO MODERATE CONFIDENCE.
&&
.MTR WATCHES/WARNINGS/ADVISORIES...
.TNGT...NONE.
$$
PUBLIC FORECAST: STROBIN
AVIATION/MARINE: CW
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AREA FORECAST DISCUSSION
NWS DENVER/BOULDER CO
1136 AM MDT TUE MAR 19 2013
.UPDATE...
&&
.AVIATION...LATEST SURFACE ANALYSIS SHOWING PRESSURE RISES ACROSS
MUCH OF THE PLAINS AS SURFACE HIGH SLIDES ACROSS NORTHEAST
COLORADO. NOW APPEARS THAT NORTHEASTERLIES MAY HANG ON A BIT
LONGER AT AREA AIRPORTS. WILL DELAY THE NORTHWESTERLIES TILL 20Z.
&&
.PREV DISCUSSION... /ISSUED 1044 AM MDT TUE MAR 19 2013/
UPDATE...
SHORT TERM...MODERATE TO STRONG NORTHWEST FLOW ALOFT CURRENTLY
OVER THE AREA. AIRMASS FAIRLY DRY WITH HUMIDITY HEADING TOWARD
THE TEENS ACROSS THE FOOTHILLS AND PLAINS. SURFACE ANTICYCLONE IN
THE DENVER AREA AT THIS TIME. SPEEDS A BIT STRONGER THAN
ADVERTISED ALONG THE URBAN CORRIDOR...PROBABLY DUE TO ENHANCEMENT
FROM CHEYENNE RIDGE. WINDS SHOULD SHIFT TO THE NORTHWEST BY THE
AFTERNOON ONCE MIXING COMMENCES. RED FLAG WARNING FOR NORTHERN
FOOTHILLS AND PORTIONS OF URBAN CORRIDOR STILL SEEMS ON TRACK.
FURTHER EAST...STILL SOME QUESTION WHETHER HUMIDITY WILL GET TO
CRITICAL FIRE WEATHER THRESHOLDS. WILL HOLD OFF ON HOISTING AT
THIS TIME. OVERALL CURRENT FORECASTS SEEM ON TRACK FOR THIS
AFTERNOON...THOUGH MAY NEED TO ADJUST THE TIMING OF THE NORTHWEST
WINDS ALONG URBAN CORRIDOR A BIT LATER IF ANTICYCLONE PERSISTS.
AVIATION...FAIRLY STRONG ANTICYCLONE IN PLACE...WITH NORTHERLY
WINDS PERSISTING AT AREA AIRPORTS. LATEST MODELS CONTINUE TO SHOW
NORTHWESTERLIES DOMINATING BY 18Z WITH SOME GUSTS TO 25 KTS. THIS
STILL SEEMS REASONABLE ONCE MIXING OCCURS. WILL CONTINUE THE
TRENDS OF THE CURRENT TAFS FOR THE UPCOMING ISSUANCE. WINDS SHOULD
DECREASE AFTER 00Z. WEAK FRONT STILL EXPECTED TO PUSH ACROSS THE
DENVER AREA AROUND 03Z WITH LIGHT NORTHEAST OR EAST WINDS...THEN
DRAINAGE BY MIDNIGHT. WITH DRY AIRMASS...DOES NOT LOOK LIKE ANY
STRATUS WILL DEVELOP.
PREV DISCUSSION... /ISSUED 313 AM MDT TUE MAR 19 2013/
SHORT TERM...MAIN ISSUE THIS TODAY WILL BE FIRE WX POTENTIAL IN
THE NRN FOOTHILLS AND ALONG THE WY BORDER. LATEST RAP HAS
HUMIDITIES DROPPING BELOW 15% BY EARLY AFTN ALONG THE FRONT RANGE
AND IN THE NRN FOOTHILLS WITH GUSTY NWLY WINDS DEVELOPING. FIRE
WX MANAGERS INDICATE HIGH FIRE POTENTIAL IN THE NRN FOOTHILLS AND
FM NORTH OF DENVER TO THE WY BORDER. WITH THAT IN MIND WILL ISSUE
A RED FLAG WARNING NORTH OF A LINE FROM BOULDER TO DENVER UP TO
THE WY BORDER FM 18Z-00Z.
OTHERWISE THE FLOW ALOFT WILL REMAIN WNW WITH SOME HIGHER LEVEL
MOISTURE MOVING ACROSS PRODUCING SOME HI LVL CLOUD COVER. AT THE
SFC A COOL FNT WILL MOVE ACROSS THE FAR NERN PLAINS WHICH WILL
BRING IN SOME SLIGHTLY COOLER AIR. THUS WILL KEEP HIGHS IN THE
UPPER 40S OVER THE FAR NERN PLAINS WITH LOWER 50S ALONG THE FRONT
RANGE URBAN CORRIDOR. FOR TONIGHT OUTSIDE OF SOME MID AND HIGH
LEVEL CLOUDS IT WILL BE DRY. WINDS SHOULD DIE DOWN BY SUNSET WITH
AN INCREASE IN HUMIDITY LEVELS WHICH WILL DECREASE FIRE DANGER.
LONG TERM...A PROGRESSIVE PATTERN THROUGH LATE WEEK AS WEDNESDAY
WILL SEE THE RIDGE ALOFT FLATTEN AS IT MOVES OVER COLORADO AND
ADJACENT REGIONS. WEDNESDAY SHOULD BE THE WARMEST DAY OF THE WEEK
AND RELATIVELY DRY WITH LESS WIND. HOWEVER...MOISTURE WILL BE
QUICKLY SPREADING INTO THE MOUNTAINS LATE WEDNESDAY AFTERNOON IN
ADVANCE OF NEXT WEAK WAVE IN THE NORTHWEST FLOW PATTERN. EXPECT
THE MOUNTAINS TO BENEFIT THE MOST WITH DECENT OROGRAPHIC FLOW AND
MODEST LAPSE RATES. THE UPPER LEVEL TROF WILL MOVE ACROSS COLORADO
ON THURSDAY WITH ASSOCIATED COLD FRONT ACROSS NORTHEAST COLORADO
LATE THURSDAY AFTERNOON WITH SCATTERED SHOWERS. SURFACE WIND IS
MAINLY DOWNSLOPE NORTHWEST WIND BUT ENOUGH INSTABILITY FOR
SCATTERED SHOWERS TO GENERATE.
THE MAIN QUESTION IN THE LONG TERM CONCERNS THE NEXT BIGGER UPPER
LOW WHICH IS FORECAST TO DEVELOP OVER WESTERN COLORADO EARLY
SATURDAY MORNING BEFORE MOVING INTO THE TEXAS PANHANDLE BY LATE
SATURDAY NIGHT. THE LONG RANGE MODELS HAVE SHOWN MORE CONSISTENCY
WITH THIS SCENARIO WHICH HAD BEEN A BIG CHANGE FROM THE MODEL
RUNS SEVERAL DAYS AGO. RIGHT NOW THE EUROPEAN AND CANADIAN RUNS
ARE SHOWING THE DEEPEST LOW NEAR THE 4 CORNERS WHILE THE GFS IS A
BIT MORE PROGRESSIVE AND MORE OF AN OPEN WAVE ACROSS COLORADO. IF
THE EUROPEAN AND FRIENDS VERIFY...IT COULD MEAN A POTENTIAL FOR
HEAVY SNOW ON SATURDAY OVER THE EAST SLOPES AND NORTHEAST PLAINS.
STILL A WAYS TO GO AS WOULD EXPECT FUTURE MODEL CORRECTIONS AS WE
GET CLOSER TO THE EVENT. CERTAINLY SOME POTENTIAL AND MAJOR
IMPACTS IF IT VERIFIES. WON`T CHANGE MUCH TO CURRENT ZONES WITH
CHANCE OF SNOW OVER ENTIRE AREA THROUGH EARLY IN THE WEEKEND. IF
CONSISTENCY CONTINUES WILL LIKELY INCREASE POPS IN LATER SHIFTS.
AVIATION...WINDS EARLY THIS MORNING HAVE BEEN WNW AROUND 10 KTS.
WITH NWLY LOW LVL FLOW OVER THE CHEYENNE RIDGE MAY SEE A LONGMONT
ANTI CYCLONE THRU LATE MORNING WITH WINDS BECOMING MORE NLY BY
15Z THRU MIDDAY. BY EARLY AFTN THE STRONGER FLOW ALOFT MAY MIX
DOWN TO THE SFC ALLOW FOR GUSTY NWLY WINDS TO DVLP WITH SPEEDS IN
THE 15-20 MPH RANGE WITH A FEW GUSTS TO 25 MPH. BY 00Z IT APPEARS
WINDS SHOULD DECREASE BACK TO 10-15 MPH. DURING THE EVENING A WK
FNT IS FCST TO BACKDOOR INTO THE AREA WITH WINDS BECOMING LIGHT
ELY WHICH GRADUALLY BECOME DRAINAGE AFTER MIDNIGHT. THERE IS VERY
LITTLE MOISTURE WITH THIS FNT SO DO NOT EXPECT ANY STRATUS
OVERNIGHT.
&&
.BOU WATCHES/WARNINGS/ADVISORIES...
RED FLAG WARNING UNTIL 6 PM MDT THIS EVENING FOR COZ215-238-239-
243.
&&
$$
SHORT TERM...D-L
LONG TERM....ENTREKIN
AVIATION...D-L
AREA FORECAST DISCUSSION
NWS DENVER/BOULDER CO
1044 AM MDT TUE MAR 19 2013
.UPDATE...
&&
.SHORT TERM...MODERATE TO STRONG NORTHWEST FLOW ALOFT CURRENTLY
OVER THE AREA. AIRMASS FAIRLY DRY WITH HUMIDITY HEADING TOWARD
THE TEENS ACROSS THE FOOTHILLS AND PLAINS. SURFACE ANTICYCLONE IN
THE DENVER AREA AT THIS TIME. SPEEDS A BIT STRONGER THAN
ADVERTISED ALONG THE URBAN CORRIDOR...PROBABLY DUE TO ENHANCEMENT
FROM CHEYENNE RIDGE. WINDS SHOULD SHIFT TO THE NORTHWEST BY THE
AFTERNOON ONCE MIXING COMMENCES. RED FLAG WARNING FOR NORTHERN
FOOTHILLS AND PORTIONS OF URBAN CORRIDOR STILL SEEMS ON TRACK.
FURTHER EAST...STILL SOME QUESTION WHETHER HUMIDITY WILL GET TO
CRITICAL FIRE WEATHER THRESHOLDS. WILL HOLD OFF ON HOISTING AT
THIS TIME. OVERALL CURRENT FORECASTS SEEM ON TRACK FOR THIS
AFTERNOON...THOUGH MAY NEED TO ADJUST THE TIMING OF THE NORTHWEST
WINDS ALONG URBAN CORRIDOR A BIT LATER IF ANTICYCLONE PERSISTS.
.AVIATION...FAIRLY STRONG ANTICYCLONE IN PLACE...WITH NORTHERLY
WINDS PERSISTING AT AREA AIRPORTS. LATEST MODELS CONTINUE TO SHOW
NORTHWESTERLIES DOMINATING BY 18Z WITH SOME GUSTS TO 25 KTS. THIS
STILL SEEMS REASONABLE ONCE MIXING OCCURS. WILL CONTINUE THE
TRENDS OF THE CURRENT TAFS FOR THE UPCOMING ISSUANCE. WINDS SHOULD
DECREASE AFTER 00Z. WEAK FRONT STILL EXPECTED TO PUSH ACROSS THE
DENVER AREA AROUND 03Z WITH LIGHT NORTHEAST OR EAST WINDS...THEN
DRAINAGE BY MIDNIGHT. WITH DRY AIRMASS...DOES NOT LOOK LIKE ANY
STRATUS WILL DEVELOP.
&&
.PREV DISCUSSION... /ISSUED 313 AM MDT TUE MAR 19 2013/
SHORT TERM...MAIN ISSUE THIS TODAY WILL BE FIRE WX POTENTIAL IN
THE NRN FOOTHILLS AND ALONG THE WY BORDER. LATEST RAP HAS
HUMIDITIES DROPPING BELOW 15% BY EARLY AFTN ALONG THE FRONT RANGE
AND IN THE NRN FOOTHILLS WITH GUSTY NWLY WINDS DEVELOPING. FIRE
WX MANAGERS INDICATE HIGH FIRE POTENTIAL IN THE NRN FOOTHILLS AND
FM NORTH OF DENVER TO THE WY BORDER. WITH THAT IN MIND WILL ISSUE
A RED FLAG WARNING NORTH OF A LINE FROM BOULDER TO DENVER UP TO
THE WY BORDER FM 18Z-00Z.
OTHERWISE THE FLOW ALOFT WILL REMAIN WNW WITH SOME HIGHER LEVEL
MOISTURE MOVING ACROSS PRODUCING SOME HI LVL CLOUD COVER. AT THE
SFC A COOL FNT WILL MOVE ACROSS THE FAR NERN PLAINS WHICH WILL
BRING IN SOME SLIGHTLY COOLER AIR. THUS WILL KEEP HIGHS IN THE
UPPER 40S OVER THE FAR NERN PLAINS WITH LOWER 50S ALONG THE FRONT
RANGE URBAN CORRIDOR. FOR TONIGHT OUTSIDE OF SOME MID AND HIGH
LEVEL CLOUDS IT WILL BE DRY. WINDS SHOULD DIE DOWN BY SUNSET WITH
AN INCREASE IN HUMIDITY LEVELS WHICH WILL DECREASE FIRE DANGER.
LONG TERM...A PROGRESSIVE PATTERN THROUGH LATE WEEK AS WEDNESDAY
WILL SEE THE RIDGE ALOFT FLATTEN AS IT MOVES OVER COLORADO AND
ADJACENT REGIONS. WEDNESDAY SHOULD BE THE WARMEST DAY OF THE WEEK
AND RELATIVELY DRY WITH LESS WIND. HOWEVER...MOISTURE WILL BE
QUICKLY SPREADING INTO THE MOUNTAINS LATE WEDNESDAY AFTERNOON IN
ADVANCE OF NEXT WEAK WAVE IN THE NORTHWEST FLOW PATTERN. EXPECT
THE MOUNTAINS TO BENEFIT THE MOST WITH DECENT OROGRAPHIC FLOW AND
MODEST LAPSE RATES. THE UPPER LEVEL TROF WILL MOVE ACROSS COLORADO
ON THURSDAY WITH ASSOCIATED COLD FRONT ACROSS NORTHEAST COLORADO
LATE THURSDAY AFTERNOON WITH SCATTERED SHOWERS. SURFACE WIND IS
MAINLY DOWNSLOPE NORTHWEST WIND BUT ENOUGH INSTABILITY FOR
SCATTERED SHOWERS TO GENERATE.
THE MAIN QUESTION IN THE LONG TERM CONCERNS THE NEXT BIGGER UPPER
LOW WHICH IS FORECAST TO DEVELOP OVER WESTERN COLORADO EARLY
SATURDAY MORNING BEFORE MOVING INTO THE TEXAS PANHANDLE BY LATE
SATURDAY NIGHT. THE LONG RANGE MODELS HAVE SHOWN MORE CONSISTENCY
WITH THIS SCENARIO WHICH HAD BEEN A BIG CHANGE FROM THE MODEL
RUNS SEVERAL DAYS AGO. RIGHT NOW THE EUROPEAN AND CANADIAN RUNS
ARE SHOWING THE DEEPEST LOW NEAR THE 4 CORNERS WHILE THE GFS IS A
BIT MORE PROGRESSIVE AND MORE OF AN OPEN WAVE ACROSS COLORADO. IF
THE EUROPEAN AND FRIENDS VERIFY...IT COULD MEAN A POTENTIAL FOR
HEAVY SNOW ON SATURDAY OVER THE EAST SLOPES AND NORTHEAST PLAINS.
STILL A WAYS TO GO AS WOULD EXPECT FUTURE MODEL CORRECTIONS AS WE
GET CLOSER TO THE EVENT. CERTAINLY SOME POTENTIAL AND MAJOR
IMPACTS IF IT VERIFIES. WON`T CHANGE MUCH TO CURRENT ZONES WITH
CHANCE OF SNOW OVER ENTIRE AREA THROUGH EARLY IN THE WEEKEND. IF
CONSISTENCY CONTINUES WILL LIKELY INCREASE POPS IN LATER SHIFTS.
AVIATION...WINDS EARLY THIS MORNING HAVE BEEN WNW AROUND 10 KTS.
WITH NWLY LOW LVL FLOW OVER THE CHEYENNE RIDGE MAY SEE A LONGMONT
ANTI CYCLONE THRU LATE MORNING WITH WINDS BECOMING MORE NLY BY
15Z THRU MIDDAY. BY EARLY AFTN THE STRONGER FLOW ALOFT MAY MIX
DOWN TO THE SFC ALLOW FOR GUSTY NWLY WINDS TO DVLP WITH SPEEDS IN
THE 15-20 MPH RANGE WITH A FEW GUSTS TO 25 MPH. BY 00Z IT APPEARS
WINDS SHOULD DECREASE BACK TO 10-15 MPH. DURING THE EVENING A WK
FNT IS FCST TO BACKDOOR INTO THE AREA WITH WINDS BECOMING LIGHT
ELY WHICH GRADUALLY BECOME DRAINAGE AFTER MIDNIGHT. THERE IS VERY
LITTLE MOISTURE WITH THIS FNT SO DO NOT EXPECT ANY STRATUS
OVERNIGHT.
&&
.BOU WATCHES/WARNINGS/ADVISORIES...
RED FLAG WARNING UNTIL 6 PM MDT THIS EVENING FOR COZ215-238-239-
243.
&&
$$
SHORT TERM...D-L
LONG TERM....ENTREKIN
AVIATION...D-L
AREA FORECAST DISCUSSION
NWS DENVER/BOULDER CO
313 AM MDT TUE MAR 19 2013
.SHORT TERM...MAIN ISSUE THIS TODAY WILL BE FIRE WX POTENTIAL IN
THE NRN FOOTHILLS AND ALONG THE WY BORDER. LATEST RAP HAS
HUMIDITIES DROPPING BELOW 15% BY EARLY AFTN ALONG THE FRONT RANGE
AND IN THE NRN FOOTHILLS WITH GUSTY NWLY WINDS DEVELOPING. FIRE
WX MANAGERS INDICATE HIGH FIRE POTENTIAL IN THE NRN FOOTHILLS AND
FM NORTH OF DENVER TO THE WY BORDER. WITH THAT IN MIND WILL ISSUE
A RED FLAG WARNING NORTH OF A LINE FROM BOULDER TO DENVER UP TO
THE WY BORDER FM 18Z-00Z.
OTHERWISE THE FLOW ALOFT WILL REMAIN WNW WITH SOME HIGHER LEVEL
MOISTURE MOVING ACROSS PRODUCING SOME HI LVL CLOUD COVER. AT THE
SFC A COOL FNT WILL MOVE ACROSS THE FAR NERN PLAINS WHICH WILL
BRING IN SOME SLIGHTLY COOLER AIR. THUS WILL KEEP HIGHS IN THE
UPPER 40S OVER THE FAR NERN PLAINS WITH LOWER 50S ALONG THE FRONT
RANGE URBAN CORRIDOR. FOR TONIGHT OUTSIDE OF SOME MID AND HIGH
LEVEL CLOUDS IT WILL BE DRY. WINDS SHOULD DIE DOWN BY SUNSET WITH
AN INCREASE IN HUMIDITY LEVELS WHICH WILL DECREASE FIRE DANGER.
.LONG TERM...A PROGRESSIVE PATTERN THROUGH LATE WEEK AS WEDNESDAY
WILL SEE THE RIDGE ALOFT FLATTEN AS IT MOVES OVER COLORADO AND
ADJACENT REGIONS. WEDNESDAY SHOULD BE THE WARMEST DAY OF THE WEEK
AND RELATIVELY DRY WITH LESS WIND. HOWEVER...MOISTURE WILL BE
QUICKLY SPREADING INTO THE MOUNTAINS LATE WEDNESDAY AFTERNOON IN
ADVANCE OF NEXT WEAK WAVE IN THE NORTHWEST FLOW PATTERN. EXPECT
THE MOUNTAINS TO BENEFIT THE MOST WITH DECENT OROGRAPHIC FLOW AND
MODEST LAPSE RATES. THE UPPER LEVEL TROF WILL MOVE ACROSS COLORADO
ON THURSDAY WITH ASSOCIATED COLD FRONT ACROSS NORTHEAST COLORADO
LATE THURSDAY AFTERNOON WITH SCATTERED SHOWERS. SURFACE WIND IS
MAINLY DOWNSLOPE NORTHWEST WIND BUT ENOUGH INSTABILITY FOR
SCATTERED SHOWERS TO GENERATE.
THE MAIN QUESTION IN THE LONG TERM CONCERNS THE NEXT BIGGER UPPER
LOW WHICH IS FORECAST TO DEVELOP OVER WESTERN COLORADO EARLY
SATURDAY MORNING BEFORE MOVING INTO THE TEXAS PANHANDLE BY LATE
SATURDAY NIGHT. THE LONG RANGE MODELS HAVE SHOWN MORE CONSISTENCY
WITH THIS SCENARIO WHICH HAD BEEN A BIG CHANGE FROM THE MODEL
RUNS SEVERAL DAYS AGO. RIGHT NOW THE EUROPEAN AND CANADIAN RUNS
ARE SHOWING THE DEEPEST LOW NEAR THE 4 CORNERS WHILE THE GFS IS A
BIT MORE PROGRESSIVE AND MORE OF AN OPEN WAVE ACROSS COLORADO. IF
THE EUROPEAN AND FRIENDS VERIFY...IT COULD MEAN A POTENTIAL FOR
HEAVY SNOW ON SATURDAY OVER THE EAST SLOPES AND NORTHEAST PLAINS.
STILL A WAYS TO GO AS WOULD EXPECT FUTURE MODEL CORRECTIONS AS WE
GET CLOSER TO THE EVENT. CERTAINLY SOME POTENTIAL AND MAJOR
IMPACTS IF IT VERIFIES. WON`T CHANGE MUCH TO CURRENT ZONES WITH
CHANCE OF SNOW OVER ENTIRE AREA THROUGH EARLY IN THE WEEKEND. IF
CONSISTENCY CONTINUES WILL LIKELY INCREASE POPS IN LATER SHIFTS.
&&
.AVIATION...WINDS EARLY THIS MORNING HAVE BEEN WNW AROUND 10 KTS.
WITH NWLY LOW LVL FLOW OVER THE CHEYENNE RIDGE MAY SEE A LONGMONT
ANTI CYCLONE THRU LATE MORNING WITH WINDS BECOMING MORE NLY BY
15Z THRU MIDDAY. BY EARLY AFTN THE STRONGER FLOW ALOFT MAY MIX
DOWN TO THE SFC ALLOW FOR GUSTY NWLY WINDS TO DVLP WITH SPEEDS IN
THE 15-20 MPH RANGE WITH A FEW GUSTS TO 25 MPH. BY 00Z IT APPEARS
WINDS SHOULD DECREASE BACK TO 10-15 MPH. DURING THE EVENING A WK
FNT IS FCST TO BACKDOOR INTO THE AREA WITH WINDS BECOMING LIGHT
ELY WHICH GRADUALLY BECOME DRAINAGE AFTER MIDNIGHT. THERE IS VERY
LITTLE MOISTURE WITH THIS FNT SO DO NOT EXPECT ANY STRATUS
OVERNIGHT.
&&
.BOU WATCHES/WARNINGS/ADVISORIES...
RED FLAG WARNING FROM NOON TODAY TO 6 PM MDT THIS EVENING FOR
COZ215-238-239-242-243.
&&
$$
SHORT TERM...RPK
LONG TERM....ENTREKIN
AVIATION...RPK
AREA FORECAST DISCUSSION
NWS NEW YORK NY
1050 AM EDT TUE MAR 19 2013
.SYNOPSIS...
A COASTAL LOW JUST OFF TO OUR EAST HEADS NORTHEAST TODAY AND
TONIGHT...AND INTO THE CANADIAN MARITIMES ON WEDNESDAY. ANOTHER
COASTAL LOW WILL DEVELOP OFF THE MID ATLANTIC COAST WEDNESDAY
NIGHT...AND TRACK WELL SOUTHEAST OF LONG ISLAND THURSDAY AND WELL
EAST OF CAPE COD THURSDAY NIGHT. WEAK HIGH PRESSURE WILL BUILD IN
ON FRIDAY AND REMAIN THROUGH THE WEEKEND. LOW PRESSURE WILL PASS
TO THE SOUTH EARLY NEXT WEEK.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
BAND OF PCPN...MOSTLY RAIN...MOVES ACROSS THE CWA LATE THIS
MORNING INTO EARLY AFTERNOON. HAVE ISSUED AN SPS FOR THE DURATION
OF THE MORNING FOR THE POTENTIAL OF ADDITIONAL LIGHT ICE
ACCUMULATION FOR THE NORTHERN FRINGE ZONES AND LET THE WINTER
STORM WARNING EXPIRE. TEMPERATURES HERE COULD STILL BE AROUND OR
JUST ABOVE FREEZING DURING THIS TIME. BASED ON OBS TO THE WEST AND
THE ANTICIPATION OF COLDER AIR MOVING IN ALOFT...SOME SNOW MAY BE
MIXED IN AS WELL WITH THIS BAND MOVING THROUGH.
FOR HIGH TEMPS...BLENDED MAV/MET WITH COLDER 04Z RAP 2M
TEMPS...WITH HIGHS ONLY NEAR 40 INLAND WHICH COULD STILL BE A
LITTLE GENEROUS ESPECIALLY ACROSS SRN CT...AND MID 40S FOR NYC
METRO AND LONG ISLAND.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH FRIDAY/...
FAST W TO WSW FLOW ALOFT TONIGHT AND THURSDAY AS CLOSED LOW BUILDS
INTO NORTHERN NEW ENGLAND...THEN SE CANADA. SHOULD BE DRY TONIGHT
AND THURSDAY WITH LITTLE IF ANY IN THE WAY OF FORCING - HOWEVER IF
UPPER TROUGH AXIS IS A TAD SLOWER IN PUSHING THROUGH THAN CURRENTLY
FORECAST COULD SEE SOME -SHSN ACROSS NORTHERN ZONES EARLY THIS
EVENING. FOR LOWS TONIGHT USED A BLEND OF MAV/MET GUIDANCE WITH
VALUES FORECAST TO BE A FEW DEGREES ABOVE NORMAL. USED A BLEND OF
MAV/MET GUIDANCE WITH NAM 2-METER TEMPERATURES AND A MIX DOWN FROM
850 HPA NEAR THE IMMEDIATE COAST...800 HPA ACROSS FAR INTERIOR
AREAS AND 825 HPA IN BETWEEN. THIS YIELDS HIGHS AROUND 10 DEGREES
BELOW NORMAL.
A COASTAL LOW DEVELOPS OFF THE MID ATLANTIC COAST WEDNESDAY NIGHT IN
RESPONSE TO A SOUTHERN STREAM SHORTWAVE MOVING OFFSHORE - THIS LOW
THEN MOVES WELL SE OF LONG ISLAND THURSDAY AND TO THE E OF CAPE COD
THURSDAY NIGHT AS THE NORTHERN STREAM CUTOFF LOW PIVOTS TO THE SE
INTO THE TRI-STATE. THE RESULT WILL BE CHANCE POPS COASTAL
AREAS/SLIGHT CHANCE POPS ELSEWHERE FOR LIGHT SNOW FROM LATE
WEDNESDAY NIGHT INTO THURSDAY EVENING - EXCEPT OVER FAR NW ZONES
WHERE ONLY COULD SEE A FEW FLURRIES.
USED A BLEND OF MAV/MET GUIDANCE FOR LOWS WEDNESDAY NIGHT WITH
VALUES FORECAST TO BE AROUND 5 DEGREES BELOW NORMAL. USED A BLEND
OF MIXING DOWN FROM 850 HPA NEAR THE COAST...800 HPA WELL
INLAND...AND 825 HPA IN BETWEEN...WITH A BLEND OF MAV/MET
GUIDANCE...AND NAM AND ECMWF 2-METER TEMPERATURES. THIS YIELDS
VALUES 10-15 DEGREES BELOW NORMAL. FOR LOWS THURSDAY NIGHT USED A
BLEND OF MEX/MEX ENSEMBLE MEAN/ECE/WPC GUIDANCE WITH VALUES AROUND
5 DEGREES BELOW NORMAL.
NW FLOW ALOFT FRIDAY WITH UPPER LOW OVER N AND E NEW ENGLAND - COULD
GET ENOUGH FORCING OUT OUT OF A PASSING SHORTWAVE IN THE AFTERNOON
TO WARRANT SLIGHT CHANCE POPS FOR -SHSN/-SHRA OVER FAR NW ZONES. FOR
HIGHS USED A BLEND OF MEX/MEX ENSEMBLE MEAN/ECE/WPC GUIDANCE WITH
VALUES AROUND 10 DEGREES BELOW NORMAL.
&&
.LONG TERM /FRIDAY NIGHT THROUGH MONDAY/...
MODELS BEGINNING TO COME INTO BETTER AGREEMENT WITH THE HANDLING
AND TIMING OF HIGH PRESSURE SYSTEM OVER THE COMING WEEKEND...AND
THE NEXT LOW PRESSURE SYSTEM FOR NEXT MONDAY/TUESDAY.
HIGH PRESSURE BUILDS TO THE SOUTH OVER THE NORTHEAST SATURDAY INTO
SUNDAY UNDER A BROAD UPPER LEVEL TROUGH. MULTIPLE SHORTWAVES
EXPECTED TO PASS THROUGH THE REGION WHILE ROTATING AROUND THE MAIN
UPPER LEVEL CLOSED LOW. DESPITE DECENT FORCING ASSOCIATED WITH EACH
PASSING WAVE...A PERSISTENT NORTHWESTERLY FLOW WILL KEEP A MAINLY
DRY VERTICAL COLUMN...RESULTING IN DRY CONDITIONS ACROSS THE AREA.
WHILE THE 12Z/18 RUNS HAD MUCH HIGHER DISCREPANCIES IN THE HANDLING
OF THE NEXT LOW...THE 00Z/19 RUNS ARE STARTING TO COME INTO BETTER
ALIGNMENT BUT STILL WITH SOME DIFFERENCES. LOW PRESSURE FORMS OVER
THE CENTRAL STATES ON SUNDAY...PROGRESSING TO THE EAST TO BEGIN
THE WEEK. 00Z ECMWF ACTUALLY THE MORE PROGRESSIVE OF THE SOLUTIONS...
WITH THE GFS LAGGING BEHIND WHILE DEVELOPING A SECONDARY LOW. THE
GFS THEN KEEPS THE UPPER LEVEL LOW FROM OVER THE WEEKEND NEARLY
STATIONARY...ALLOWING FOR POSSIBLE INTERACTION WITH THE NEXT LOW
TRAVERSING THE CENTRAL US...RESULTING IN MORE WIDESPREAD
PRECIPITATION. HOWEVER...THE PATTERN OF THE ECMWF KEEPS THE
TRAVERSING LOW TO THE SOUTH...BUILDING IN SUBSIDENCE OVER MOST OF
THE NORTHEAST...KEEPING THE HEAVIEST PRECIPITATION TO THE SOUTH.
BECAUSE OF THE MODEL SPREAD...CONTINUED THE SLIGHT CHANCE POPS FOR
MONDAY INTO TUESDAY.
GENERALLY USED A BLEND OF THE WPC AND MOS GUIDANCE FOR TEMPS THIS
WEEKEND INTO NEXT WEEK...WHICH KEEPS HIGH TEMPS SLIGHTLY BELOW
NORMAL AND OVERNIGHT LOWS RIGHT AROUND TO SLIGHTLY BELOW NORMAL.
&&
.AVIATION /15Z TUESDAY THROUGH SATURDAY/...
LOW PRESSURE IS SOUTH OF LONG ISLAND THIS MORNING. THIS LOW WILL
WILL MOVE NORTHEAST INTO COASTAL NEW ENGLAND THIS EVENING.
WINDS ARE FROM THE NORTHEAST WITH IFR CIGS. AN AREA OF SHOWERS AND
LIGHT DRIZZLE WILL MOVE THROUGH THE TERMINALS THROUGH THE LATER
MORNING AND EARLY AFTERNOON HOURS. BY AFTERNOON...AS THE LOW MOVES
NORTHEAST...WINDS WILL BECOME MORE WESTERLY AND GUST TO 20-30KT.
IFR CIGS WILL ALSO RAPIDLY INCREASE TO VFR.
WESTERLY WINDS CONTINUE OVERNIGHT WITH SPEEDS DIMINISHING AND
GUSTS ENDING. VFR CONDITIONS OVERNIGHT.
NY METRO ENHANCED AVIATION WEATHER SUPPORT...
DETAILED INFORMATION...INCLUDING HOURLY TAF WIND COMPONENT FCSTS
CAN BE FOUND AT: HTTP:/WWW.ERH.NOAA.GOV/ZNY/N90 (LOWER CASE)
KJFK FCSTER COMMENTS: WIND SHIFT TO NORTHWEST AND IFR CIGS
IMPROVING TO VFR COULD BE OFF BY AN HOUR OR TWO. VFR CIGS EXPECTED
BY 19Z. AMENDMENTS POSSIBLE.
KLGA FCSTER COMMENTS: WIND SHIFT TO NORTHWEST AND IFR CIGS
IMPROVING TO VFR COULD BE OFF BY AN HOUR OR TWO. VFR CIGS EXPECTED
BY 19Z. AMENDMENTS POSSIBLE.
KEWR FCSTER COMMENTS: WIND SHIFT TO NORTHWEST AND IFR CIGS
IMPROVING TO VFR COULD BE OFF BY AN HOUR OR TWO. VFR CIGS EXPECTED
BY 19Z. AMENDMENTS POSSIBLE.
THE AFTERNOON KEWR HAZE POTENTIAL FORECAST IS YELLOW...WHICH
IMPLIES SLANT RANGE VISIBILITY 4-6SM OUTSIDE OF CLOUD.
KTEB FCSTER COMMENTS: WIND SHIFT TO NORTHWEST AND IFR CIGS
IMPROVING TO VFR COULD BE OFF BY AN HOUR OR TWO. VFR CIGS EXPECTED
BY 19Z. AMENDMENTS POSSIBLE.
KHPN FCSTER COMMENTS: WIND SHIFT TO NORTHWEST AND IFR CIGS
IMPROVING TO VFR COULD BE OFF BY AN HOUR OR TWO. VFR CIGS EXPECTED
BETWEEN 19Z-20Z. AMENDMENTS POSSIBLE.
KISP FCSTER COMMENTS: WIND SHIFT TO NORTHWEST AND IFR CIGS
IMPROVING TO VFR COULD BE OFF BY AN HOUR OR TWO. VFR CIGS EXPECTED
BETWEEN 20Z-21Z. AMENDMENTS POSSIBLE.
.OUTLOOK FOR 12Z WED THROUGH SAT...
.WED...GENERALLY VFR. W WINDS WITH GUSTS INTO THE LOWER 20 KT
RANGE ON WED.
.THU...CHANCE OF SUB-VFR IN LIGHT SNOW.
.FRI...VFR. GUSTY NW WINDS POSSIBLE.
.SAT...VFR.
&&
.MARINE...
MINOR CHANGES THIS UPDATE TO REFLECT THE LATEST TRENDS IN
OBSERVATIONS AND GUIDANCE.
OCCASIONAL GUSTS UP TO 35 KT WILL BE POSSIBLE ACROSS THE EASTERN
WATERS FOR THE DURATION OF THE MORNING AS THE PRESSURE GRADIENT
WILL BE RELATIVELY TIGHTER HERE DUE TO THE PROXIMITY OF A LOW
PRESSURE CENTER JUST OFF TO THE SOUTH OF MONTAUK. OTHERWISE...SCA
CONDITIONS EXPECTED ACROSS THE AREA TODAY.
WINDS INCREASE TONIGHT AS COASTAL LOW DEEPENS TO THE EAST - SO
HAVE ISSUED A GALE WARNING FOR ALL WATERS FOR TONIGHT. GALE GUSTS
CONTINUE ON WEDNESDAY OVER EASTERN COASTAL OCEAN WATERS -
ANZ350-353 - WITH SMALL CRAFT CONDITIONS ELSEWHERE. THE PRESSURE
GRADIENT RELAXES OVER THE REGION WEDNESDAY NIGHT...WITH ALL WATERS
FALLING BELOW SCA LEVELS AFTER MIDNIGHT..AND CONTINUE ON THURSDAY.
WIND GUSTS ON THE COASTAL OCEAN WATERS COULD REACH 25 KT THURSDAY
NIGHT IN THE WAKE OF THE DEPARTING...BUT STRENGTHENING COASTAL
LOW...WITH SUB-SMALL CRAFT CONDITIONS ON THE REMAINDER OF THE WATERS.
FRIDAY WILL FEATURE SUB-SMALL CRAFT CONDITIONS ON ALL WATERS AS THE
PRESSURE GRADIENT RELAXES...EXCEPT FOR POSSIBLY SWELLS BRING SCA
SEAS TO THE TWO EASTERN COASTAL WATER ZONES.
GENERALLY EXPECTING SUB-SCA CONDITIONS THIS WEEKEND WITH HIGH
PRESSURE BUILDING INTO THE REGION. A BRIEF PERIOD OF INTERACTION
BETWEEN THE DEPARTING LOW AND APPROACHING HIGH FRI NIGHT COULD
INCREASE WINDS ENOUGH FROM THE NORTHWEST...COMBINED WITH COLD AIR
ADVECTION TO PRODUCE 25 KT GUSTS AND 5 FT SEAS ON THE OCEAN.
CONDITIONS THEN WILL DIMINISH BY SATURDAY.
POSSIBLE SCA CONDITIONS AGAIN NEXT MONDAY AND TUESDAY WITH THE NEXT
LOW PRESSURE SYSTEM.
&&
.HYDROLOGY...
LITTLE ADDITIONAL ACCUMULATION OF RAIN TODAY. NO HYDROLOGIC IMPACT
IS EXPECTED.
DRY TONIGHT AND WEDNESDAY. THERE IS THE CHANCE FOR SOME LIGHT
PRECIPITATION FROM LATE WEDNESDAY NIGHT INTO THURSDAY EVENING
MAINLY OVER THE SE 1/2 OF THE TRI-STATE. AGAIN...NO HYDROLOGIC
IMPACT IS EXPECTED.
&&
.OKX WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
NY...NONE.
NJ...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 6 PM EDT THIS EVENING FOR ANZ330-
335-338-340-345-350-353-355.
GALE WARNING FROM 6 PM THIS EVENING TO 6 AM EDT WEDNESDAY FOR
ANZ330-335-338-340-345-355.
GALE WARNING FROM 6 PM THIS EVENING TO 6 PM EDT WEDNESDAY FOR
ANZ350-353.
&&
$$
SYNOPSIS...GOODMAN/MALOIT/SEARS
NEAR TERM...JC/GOODMAN
SHORT TERM...MALOIT
LONG TERM...SEARS
AVIATION...JM
MARINE...MALOIT/SEARS
HYDROLOGY...JC
AREA FORECAST DISCUSSION...CORRECTED
NWS NEW YORK NY
800 AM EDT TUE MAR 19 2013
.SYNOPSIS...
A COASTAL LOW WILL PASS JUST SOUTH OF LONG ISLAND TODAY...THEN
MOVE FROM THE GULF OF MAINE TONIGHT INTO THE CANADIAN MARITIMES ON
WEDNESDAY. ANOTHER COASTAL LOW WILL DEVELOP OFF THE MID ATLANTIC
COAST WEDNESDAY NIGHT...AND TRACK WELL SOUTHEAST OF LONG ISLAND
THURSDAY AND WELL EAST OF CAPE COD THURSDAY NIGHT. WEAK HIGH
PRESSURE WILL BUILD IN ON FRIDAY AND REMAIN THROUGH THE WEEKEND.
LOW PRESSURE WILL PASS TO THE SOUTH EARLY NEXT WEEK.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
1006 HPA SURFACE LOW ABOUT 65 MILES SOUTH OF KFRG WILL CONTINUE TO
MOVE ENE AND DEEPEN IN RESPONSE TO 3 HOURLY PRESSURE FALLS OF
2-2.5 HPA/HOUR.
PRECIPITATION WILL CONTINUE TO BE SPOTTY FOR THE REST OF THIS
MORNING - WITH ANOTHER LIGHT BATCH COMING IN LATER THIS MORNING IN
RESPONSE TO A SHORTWAVE CURRENTLY IN CENTRAL PA. IN THE WAKE OF THE
SHORTWAVE THIS AFTERNOON WILL EXPERIENCE MAINLY ISOLD TO SCT SHOWERS.
AS FOR P-TYPE - TEMPERATURES ACROSS ALL BUT THE WINTER STORM
WARNING AREA HAVE RISEN ABOVE FREEZING SO EXPECT RAIN/RAIN SHOWERS
OUTSIDE OF THE WINTER STORM WARNING AREA AND PERIODS OF ZR THIS
MORNING AND RAIN OR SNOW SHOWERS THIS AFTERNOON IN THE WARNING AREA.
BECAUSE TEMPERATURES HAVE RISEN ABOVE FREEZING ACROSS WESTERN
BERGEN AND EASTERN PASSAIC COUNTIES HAVE CANCELLED THE WINTER
WEATHER ADVISORY THERE.
FOR HIGH TEMPS...BLENDED MAV/MET WITH COLDER 04Z RAP 2M
TEMPS...WITH HIGHS ONLY NEAR 40 INLAND WHICH COULD STILL BE A
LITTLE GENEROUS ESPECIALLY ACROSS SRN CT...AND MID 40S FOR NYC
METRO AND LONG ISLAND.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH FRIDAY/...
FAST W TO WSW FLOW ALOFT TONIGHT AND THURSDAY AS CLOSED LOW BUILDS
INTO NORTHERN NEW ENGLAND...THEN SE CANADA. SHOULD BE DRY TONIGHT
AND THURSDAY WITH LITTLE IF ANY IN THE WAY OF FORCING - HOWEVER IF
UPPER TROUGH AXIS IS A TAD SLOWER IN PUSHING THROUGH THAN CURRENTLY
FORECAST COULD SEE SOME -SHSN ACROSS NORTHERN ZONES EARLY THIS
EVENING. FOR LOWS TONIGHT USED A BLEND OF MAV/MET GUIDANCE WITH
VALUES FORECAST TO BE A FEW DEGREES ABOVE NORMAL. USED A BLEND OF
MAV/MET GUIDANCE WITH NAM 2-METER TEMPERATURES AND A MIX DOWN FROM
850 HPA NEAR THE IMMEDIATE COAST...800 HPA ACROSS FAR INTERIOR
AREAS AND 825 HPA IN BETWEEN. THIS YIELDS HIGHS AROUND 10 DEGREES
BELOW NORMAL.
A COASTAL LOW DEVELOPS OFF THE MID ATLANTIC COAST WEDNESDAY NIGHT IN
RESPONSE TO A SOUTHERN STREAM SHORTWAVE MOVING OFFSHORE - THIS LOW
THEN MOVES WELL SE OF LONG ISLAND THURSDAY AND TO THE E OF CAPE COD
THURSDAY NIGHT AS THE NORTHERN STREAM CUTOFF LOW PIVOTS TO THE SE
INTO THE TRI-STATE. THE RESULT WILL BE CHANCE POPS COASTAL
AREAS/SLIGHT CHANCE POPS ELSEWHERE FOR LIGHT SNOW FROM LATE
WEDNESDAY NIGHT INTO THURSDAY EVENING - EXCEPT OVER FAR NW ZONES
WHERE ONLY COULD SEE A FEW FLURRIES.
USED A BLEND OF MAV/MET GUIDANCE FOR LOWS WEDNESDAY NIGHT WITH
VALUES FORECAST TO BE AROUND 5 DEGREES BELOW NORMAL. USED A BLEND
OF MIXING DOWN FROM 850 HPA NEAR THE COAST...800 HPA WELL
INLAND...AND 825 HPA IN BETWEEN...WITH A BLEND OF MAV/MET
GUIDANCE...AND NAM AND ECMWF 2-METER TEMPERATURES. THIS YIELDS
VALUES 10-15 DEGREES BELOW NORMAL. FOR LOWS THURSDAY NIGHT USED A
BLEND OF MEX/MEX ENSEMBLE MEAN/ECE/WPC GUIDANCE WITH VALUES AROUND
5 DEGREES BELOW NORMAL.
NW FLOW ALOFT FRIDAY WITH UPPER LOW OVER N AND E NEW ENGLAND - COULD
GET ENOUGH FORCING OUT OUT OF A PASSING SHORTWAVE IN THE AFTERNOON
TO WARRANT SLIGHT CHANCE POPS FOR -SHSN/-SHRA OVER FAR NW ZONES. FOR
HIGHS USED A BLEND OF MEX/MEX ENSEMBLE MEAN/ECE/WPC GUIDANCE WITH
VALUES AROUND 10 DEGREES BELOW NORMAL.
&&
.LONG TERM /FRIDAY NIGHT THROUGH MONDAY/...
MODELS BEGINNING TO COME INTO BETTER AGREEMENT WITH THE HANDLING
AND TIMING OF HIGH PRESSURE SYSTEM OVER THE COMING WEEKEND...AND
THE NEXT LOW PRESSURE SYSTEM FOR NEXT MONDAY/TUESDAY.
HIGH PRESSURE BUILDS TO THE SOUTH OVER THE NORTHEAST SATURDAY INTO
SUNDAY UNDER A BROAD UPPER LEVEL TROUGH. MULTIPLE SHORTWAVES
EXPECTED TO PASS THROUGH THE REGION WHILE ROTATING AROUND THE MAIN
UPPER LEVEL CLOSED LOW. DESPITE DECENT FORCING ASSOCIATED WITH EACH
PASSING WAVE...A PERSISTENT NORTHWESTERLY FLOW WILL KEEP A MAINLY
DRY VERTICAL COLUMN...RESULTING IN DRY CONDITIONS ACROSS THE AREA.
WHILE THE 12Z/18 RUNS HAD MUCH HIGHER DISCREPANCIES IN THE HANDLING
OF THE NEXT LOW...THE 00Z/19 RUNS ARE STARTING TO COME INTO BETTER
ALIGNMENT BUT STILL WITH SOME DIFFERENCES. LOW PRESSURE FORMS OVER
THE CENTRAL STATES ON SUNDAY...PROGRESSING TO THE EAST TO BEGIN
THE WEEK. 00Z ECMWF ACTUALLY THE MORE PROGRESSIVE OF THE SOLUTIONS...
WITH THE GFS LAGGING BEHIND WHILE DEVELOPING A SECONDARY LOW. THE
GFS THEN KEEPS THE UPPER LEVEL LOW FROM OVER THE WEEKEND NEARLY
STATIONARY...ALLOWING FOR POSSIBLE INTERACTION WITH THE NEXT LOW
TRAVERSING THE CENTRAL US...RESULTING IN MORE WIDESPREAD
PRECIPITATION. HOWEVER...THE PATTERN OF THE ECMWF KEEPS THE
TRAVERSING LOW TO THE SOUTH...BUILDING IN SUBSIDENCE OVER MOST OF
THE NORTHEAST...KEEPING THE HEAVIEST PRECIPITATION TO THE SOUTH.
BECAUSE OF THE MODEL SPREAD...CONTINUED THE SLIGHT CHANCE POPS FOR
MONDAY INTO TUESDAY.
GENERALLY USED A BLEND OF THE WPC AND MOS GUIDANCE FOR TEMPS THIS
WEEKEND INTO NEXT WEEK...WHICH KEEPS HIGH TEMPS SLIGHTLY BELOW
NORMAL AND OVERNIGHT LOWS RIGHT AROUND TO SLIGHTLY BELOW NORMAL.
&&
.AVIATION /12Z TUESDAY THROUGH SATURDAY/...
LOW PRESSURE WILL TRACK FROM THE DELMARVA TO JUST SOUTHEAST OF
NYC THIS MORNING. THE LOW PRESSURE MOVES INTO COASTAL NEW ENGLAND
THIS EVENING. INITIALLY EASTERLY GUSTS OF AROUND 20 KT WILL LOWER
AND WINDS OVERALL BECOME LIGHT AND VARIABLE LATER THIS MORNING
BEFORE BECOMING MORE WESTERLY BY THE AFTERNOON...GUSTING 20-25 KT
LATE. THERE IS SOME UNCERTAINTY ON TIMING OF THE SWITCHING
DIRECTIONS AND THE LIGHT AND VARIABLE TRANSITION COULD BE OFF BY
1-2 HOURS AS WELL AS WHEN THE WINDS BECOME WESTERLY.
ICING MAINLY RESTRICTED TO KSWF WHERE THERE IS FREEZING DRIZZLE THIS
MORNING. FOR KSWF...STORM TOTAL SNOW OF ABOUT 7 INCHES WITH ABOUT
A TENTH OF AN INCH OF ICE. ELSEWHERE...THE PRECIP TYPE IS RAIN FOR
EASTERN TERMINALS AND DRIZZLE TO THE WEST. ALL PRECIP BECOMES
DRIZZLE LATER THIS MORNING...LINGERING INTO THE AFTERNOON. MAINLY
IFR CONDITIONS WITH SOME POCKETS OF POSSIBLE LIFR WITH NO
SUBSTANTIAL IMPROVEMENT EXPECTED UNTIL WINDS BECOME MORE WESTERLY
AND START GUSTING LATE IN THE AFTERNOON GENERALLY AFTER 20Z.
POSSIBLE VLIFR POSSIBLE IN FOG THIS MORNING WHEN LOW IS WITHIN
CLOSEST PROXIMITY OF THE TERMINALS. VFR RETURNS BY THE EVENING
WITH WEST WINDS GUSTING TO 25-30 KT...DECREASING A FEW KTS
OVERNIGHT.
NY METRO ENHANCED AVIATION WEATHER SUPPORT...
DETAILED INFORMATION...INCLUDING HOURLY TAF WIND COMPONENT FCSTS
CAN BE FOUND AT: HTTP:/WWW.ERH.NOAA.GOV/ZNY/N90 (LOWER CASE)
KJFK FCSTER COMMENTS: LOW CONFIDENCE WITH VSBYS FORECAST. TIMING
OF IFR VSBYS COULD BE OFF BY A FEW HOURS. HIGH CONFIDENCE WITH
CIGS FORECAST. WIND SHIFT TO NW COULD BE 1-2 HOURS OFF. AMENDMENTS
POSSIBLE.
KLGA FCSTER COMMENTS: LOW CONFIDENCE WITH VSBYS FORECAST. TIMING
OF IFR VSBYS COULD BE OFF BY A FEW HOURS. HIGH CONFIDENCE WITH
CIGS FORECAST. WIND SHIFT TO NW COULD BE 1-2 HOURS OFF. AMENDMENTS
POSSIBLE.
KEWR FCSTER COMMENTS: LOW CONFIDENCE WITH VSBYS FORECAST. TIMING
OF IFR VSBYS COULD BE OFF BY A FEW HOURS. HIGH CONFIDENCE WITH
CIGS FORECAST. WIND SHIFT TO NW COULD BE 1-2 HOURS OFF. AMENDMENTS
POSSIBLE.
THE AFTERNOON KEWR HAZE POTENTIAL FORECAST IS YELLOW...WHICH
IMPLIES SLANT RANGE VISIBILITY 4-6SM OUTSIDE OF CLOUD.
KTEB FCSTER COMMENTS: LOW CONFIDENCE WITH VSBYS FORECAST. TIMING
OF IFR VSBYS COULD BE OFF BY A FEW HOURS. HIGH CONFIDENCE WITH
CIGS FORECAST. WIND SHIFT TO NW COULD BE 1-2 HOURS OFF. AMENDMENTS
POSSIBLE.
KHPN FCSTER COMMENTS: LOW CONFIDENCE WITH VSBYS FORECAST. TIMING
OF IFR VSBYS COULD BE OFF BY A FEW HOURS. HIGH CONFIDENCE WITH
CIGS FORECAST. WIND SHIFT TO NW COULD BE 1-2 HOURS OFF. AMENDMENTS
POSSIBLE.
KISP FCSTER COMMENTS: LOW CONFIDENCE WITH VSBYS FORECAST. TIMING
OF IFR VSBYS COULD BE OFF BY A FEW HOURS. HIGH CONFIDENCE WITH
CIGS FORECAST. WIND SHIFT TO NW COULD BE 1-2 HOURS OFF. AMENDMENTS
POSSIBLE.
.OUTLOOK FOR 12Z WED THROUGH SAT...
.WED...GENERALLY VFR. W WINDS WITH GUSTS INTO THE LOWER 20 KT
RANGE ON WED.
.THU...CHANCE OF SUB-VFR IN LIGHT SNOW.
.FRI...VFR. GUSTY NW WINDS POSSIBLE.
.SAT...VFR.
&&
.MARINE...
MINOR CHANGES THIS UPDATE TO REFLECT THE LATEST TRENDS IN
OBSERVATIONS AND GUIDANCE. FORECAST APPEARS ON TRACK.
NON ELEVATED OBSERVATIONS ACROSS THE COASTAL OCEAN WATERS INDICATE
THAT GALE FORCE GUSTS HAVE COME TO AN END - SO HAVE ALLOWED GALE
WARNING TO COME TO AN END AND HAVE REPLACED IT WITH A SMALL CRAFT
ADVISORY FOR ALL WATERS FOR TODAY. WHILE SHELTERED WATERS...
ESPECIALLY NY HARBOR AND PORTIONS OF W LONG ISLAND SOUND WILL
HAVE PERIODS OF WINDS BELOW SMALL CRAFT LEVELS - EXPECT THEM TO BE
RELATIVELY SHORT IN DURATION.
WINDS INCREASE TONIGHT AS COASTAL LOW DEEPENS TO THE EAST - SO
HAVE ISSUED A GALE WARNING FOR ALL WATERS FOR TONIGHT. GALE GUSTS
CONTINUE ON WEDNESDAY OVER EASTERN COASTAL OCEAN WATERS -
ANZ350-353 - WITH SMALL CRAFT CONDITIONS ELSEWHERE. THE PRESSURE
GRADIENT RELAXES OVER THE REGION WEDNESDAY NIGHT...WITH ALL WATERS
FALLING BELOW SCA LEVELS AFTER MIDNIGHT..AND CONTINUE ON THURSDAY.
WIND GUSTS ON THE COASTAL OCEAN WATERS COULD REACH 25 KT THURSDAY
NIGHT IN THE WAKE OF THE DEPARTING...BUT STRENGTHENING COASTAL
LOW...WITH SUB-SMALL CRAFT CONDITIONS ON THE REMAINDER OF THE WATERS.
FRIDAY WILL FEATURE SUB-SMALL CRAFT CONDITIONS ON ALL WATERS AS THE
PRESSURE GRADIENT RELAXES...EXCEPT FOR POSSIBLY SWELLS BRING SCA
SEAS TO THE TWO EASTERN COASTAL WATER ZONES.
GENERALLY EXPECTING SUB-SCA CONDITIONS THIS WEEKEND WITH HIGH
PRESSURE BUILDING INTO THE REGION. A BRIEF PERIOD OF INTERACTION
BETWEEN THE DEPARTING LOW AND APPROACHING HIGH FRI NIGHT COULD
INCREASE WINDS ENOUGH FROM THE NORTHWEST...COMBINED WITH COLD AIR
ADVECTION TO PRODUCE 25 KT GUSTS AND 5 FT SEAS ON THE OCEAN.
CONDITIONS THEN WILL DIMINISH BY SATURDAY.
POSSIBLE SCA CONDITIONS AGAIN NEXT MONDAY AND TUESDAY WITH THE NEXT
LOW PRESSURE SYSTEM.
&&
.HYDROLOGY...
LIQUID EQUIVALENT STORM TOTAL QPF OF 1.00-1.25 INCHES EXPECTED.
PRECIP LIGHT ENOUGH AT THIS TIME THAT COMBINED LIGHT RAIN AND SNOW
MELT SHOULD NOT CAUSE MUCH IN THE WAY OF PROBLEMS.
DRY TONIGHT AND WEDNESDAY. THERE IS THE CHANCE FOR SOME LIGHT
PRECIPITATION FROM LATE WEDNESDAY NIGHT INTO THURSDAY EVENING
MAINLY OVER THE SE 1/2 OF THE TRI-STATE. NO HYDROLOGIC IMPACT
IS EXPECTED.
&&
.OKX WATCHES/WARNINGS/ADVISORIES...
CT...WINTER STORM WARNING UNTIL 10 AM EDT THIS MORNING FOR
CTZ005>008.
NY...WINTER STORM WARNING UNTIL 10 AM EDT THIS MORNING FOR
NYZ067>070.
NJ...WINTER STORM WARNING UNTIL 10 AM EDT THIS MORNING FOR NJZ002.
MARINE...SMALL CRAFT ADVISORY UNTIL 6 PM EDT THIS EVENING FOR ANZ330-
335-338-340-345-350-353-355.
GALE WARNING FROM 6 PM THIS EVENING TO 6 AM EDT WEDNESDAY FOR
ANZ330-335-338-340-345-355.
GALE WARNING FROM 6 PM THIS EVENING TO 6 PM EDT WEDNESDAY FOR
ANZ350-353.
&&
$$
SYNOPSIS...GOODMAN/MALOIT/SEARS
NEAR TERM...MALOIT/GOODMAN
SHORT TERM...MALOIT
LONG TERM...SEARS
AVIATION...JM
MARINE...MALOIT/SEARS
HYDROLOGY...GOODMAN
AREA FORECAST DISCUSSION
NWS NEW YORK NY
755 AM EDT TUE MAR 19 2013
.SYNOPSIS...
A COASTAL LOW WILL PASS JUST SOUTH OF LONG ISLAND TODAY...THEN
MOVE FROM THE GULF OF MAINE TONIGHT INTO THE CANADIAN MARITIMES ON
WEDNESDAY. ANOTHER COASTAL LOW WILL DEVELOP OFF THE MID ATLANTIC
COAST WEDNESDAY NIGHT...AND TRACK WELL SOUTHEAST OF LONG ISLAND
THURSDAY AND WELL EAST OF CAPE COD THURSDAY NIGHT. WEAK HIGH
PRESSURE WILL BUILD IN ON FRIDAY AND REMAIN THROUGH THE WEEKEND.
LOW PRESSURE WILL PASS TO THE SOUTH EARLY NEXT WEEK.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
1006 HPA SURFACE LOW ABOUT 65 MILES SOUTH OF KFRG WILL CONTINUE TO
MOVE ENE AND DEEPEN IN RESPONSE TO 3 HOURLY PRESSURE FALLS OF
2-2.5 HPA/HOUR.
PRECIPITATION WILL CONTINUE TO BE SPOTTY FOR THE REST OF THIS
MORNING - WITH ANOTHER LIGHT BATCH COMING IN LATER THIS MORNING IN
RESPONSE TO A SHORTWAVE CURRENTLY IN CENTRAL PA. IN THE WAKE OF THE
SHORTWAVE THIS AFTERNOON WILL EXPERIENCE MAINLY ISOLD TO SCT SHOWERS.
AS FOR P-TYPE - TEMPERATURES ACROSS ALL BUT THE WINTER STORM
WARNING AREA HAVE RISEN ABOVE FREEZING SO EXPECT RAIN/RAIN SHOWERS
OUTSIDE OF THE WINTER STORM WARNING AREA AND PERIODS OF ZR THIS
MORNING AND RAIN OR SNOW SHOWERS THIS AFTERNOON IN THE WARNING AREA.
BECAUSE TEMPERATURES HAVE RISEN ABOVE FREEZING ACROSS WESTERN
BERGEN AND EASTERN PASSAIC COUNTIES HAVE CANCELLED THE WINTER
WEATHER ADVISORY THERE.
FOR HIGH TEMPS...BLENDED MAV/MET WITH COLDER 04Z RAP 2M
TEMPS...WITH HIGHS ONLY NEAR 40 INLAND WHICH COULD STILL BE A
LITTLE GENEROUS ESPECIALLY ACROSS SRN CT...AND MID 40S FOR NYC
METRO AND LONG ISLAND.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH FRIDAY/...
FAST W TO WSW FLOW ALOFT TONIGHT AND THURSDAY AS CLOSED LOW BUILDS
INTO NORTHERN NEW ENGLAND...THEN SE CANADA. SHOULD BE DRY TONIGHT
AND THURSDAY WITH LITTLE IF ANY IN THE WAY OF FORCING - HOWEVER IF
UPPER TROUGH AXIS IS A TAD SLOWER IN PUSHING THROUGH THAN CURRENTLY
FORECAST COULD SEE SOME -SHSN ACROSS NORTHERN ZONES EARLY THIS
EVENING. FOR LOWS TONIGHT USED A BLEND OF MAV/MET GUIDANCE WITH
VALUES FORECAST TO BE A FEW DEGREES ABOVE NORMAL. USED A BLEND OF
MAV/MET GUIDANCE WITH NAM 2-METER TEMPERATURES AND A MIX DOWN FROM
850 HPA NEAR THE IMMEDIATE COAST...800 HPA ACROSS FAR INTERIOR
AREAS AND 825 HPA IN BETWEEN. THIS YIELDS HIGHS AROUND 10 DEGREES
BELOW NORMAL.
A COASTAL LOW DEVELOPS OFF THE MID ATLANTIC COAST WEDNESDAY NIGHT IN
RESPONSE TO A SOUTHERN STREAM SHORTWAVE MOVING OFFSHORE - THIS LOW
THEN MOVES WELL SE OF LONG ISLAND THURSDAY AND TO THE E OF CAPE COD
THURSDAY NIGHT AS THE NORTHERN STREAM CUTOFF LOW PIVOTS TO THE SE
INTO THE TRI-STATE. THE RESULT WILL BE CHANCE POPS COASTAL
AREAS/SLIGHT CHANCE POPS ELSEWHERE FOR LIGHT SNOW FROM LATE
WEDNESDAY NIGHT INTO THURSDAY EVENING - EXCEPT OVER FAR NW ZONES
WHERE ONLY COULD SEE A FEW FLURRIES.
USED A BLEND OF MAV/MET GUIDANCE FOR LOWS WEDNESDAY NIGHT WITH
VALUES FORECAST TO BE AROUND 5 DEGREES BELOW NORMAL. USED A BLEND
OF MIXING DOWN FROM 850 HPA NEAR THE COAST...800 HPA WELL
INLAND...AND 825 HPA IN BETWEEN...WITH A BLEND OF MAV/MET
GUIDANCE...AND NAM AND ECMWF 2-METER TEMPERATURES. THIS YIELDS
VALUES 10-15 DEGREES BELOW NORMAL. FOR LOWS THURSDAY NIGHT USED A
BLEND OF MEX/MEX ENSEMBLE MEAN/ECE/WPC GUIDANCE WITH VALUES AROUND
5 DEGREES BELOW NORMAL.
NW FLOW ALOFT FRIDAY WITH UPPER LOW OVER N AND E NEW ENGLAND - COULD
GET ENOUGH FORCING OUT OUT OF A PASSING SHORTWAVE IN THE AFTERNOON
TO WARRANT SLIGHT CHANCE POPS FOR -SHSN/-SHRA OVER FAR NW ZONES. FOR
HIGHS USED A BLEND OF MEX/MEX ENSEMBLE MEAN/ECE/WPC GUIDANCE WITH
VALUES AROUND 10 DEGREES BELOW NORMAL.
&&
.LONG TERM /FRIDAY NIGHT THROUGH MONDAY/...
MODELS BEGINNING TO COME INTO BETTER AGREEMENT WITH THE HANDLING
AND TIMING OF HIGH PRESSURE SYSTEM OVER THE COMING WEEKEND...AND
THE NEXT LOW PRESSURE SYSTEM FOR NEXT MONDAY/TUESDAY.
HIGH PRESSURE BUILDS TO THE SOUTH OVER THE NORTHEAST SATURDAY INTO
SUNDAY UNDER A BROAD UPPER LEVEL TROUGH. MULTIPLE SHORTWAVES
EXPECTED TO PASS THROUGH THE REGION WHILE ROTATING AROUND THE MAIN
UPPER LEVEL CLOSED LOW. DESPITE DECENT FORCING ASSOCIATED WITH EACH
PASSING WAVE...A PERSISTENT NORTHWESTERLY FLOW WILL KEEP A MAINLY
DRY VERTICAL COLUMN...RESULTING IN DRY CONDITIONS ACROSS THE AREA.
WHILE THE 12Z/18 RUNS HAD MUCH HIGHER DISCREPANCIES IN THE HANDLING
OF THE NEXT LOW...THE 00Z/19 RUNS ARE STARTING TO COME INTO BETTER
ALIGNMENT BUT STILL WITH SOME DIFFERENCES. LOW PRESSURE FORMS OVER
THE CENTRAL STATES ON SUNDAY...PROGRESSING TO THE EAST TO BEGIN
THE WEEK. 00Z ECMWF ACTUALLY THE MORE PROGRESSIVE OF THE SOLUTIONS...
WITH THE GFS LAGGING BEHIND WHILE DEVELOPING A SECONDARY LOW. THE
GFS THEN KEEPS THE UPPER LEVEL LOW FROM OVER THE WEEKEND NEARLY
STATIONARY...ALLOWING FOR POSSIBLE INTERACTION WITH THE NEXT LOW
TRAVERSING THE CENTRAL US...RESULTING IN MORE WIDESPREAD
PRECIPITATION. HOWEVER...THE PATTERN OF THE ECMWF KEEPS THE
TRAVERSING LOW TO THE SOUTH...BUILDING IN SUBSIDENCE OVER MOST OF
THE NORTHEAST...KEEPING THE HEAVIEST PRECIPITATION TO THE SOUTH.
BECAUSE OF THE MODEL SPREAD...CONTINUED THE SLIGHT CHANCE POPS FOR
MONDAY INTO TUESDAY.
GENERALLY USED A BLEND OF THE WPC AND MOS GUIDANCE FOR TEMPS THIS
WEEKEND INTO NEXT WEEK...WHICH KEEPS HIGH TEMPS SLIGHTLY BELOW
NORMAL AND OVERNIGHT LOWS RIGHT AROUND TO SLIGHTLY BELOW NORMAL.
&&
.AVIATION /12Z TUESDAY THROUGH SATURDAY/...
LOW PRESSURE WILL TRACK FROM THE DELMARVA TO JUST SOUTHEAST OF
NYC THIS MORNING. THE LOW PRESSURE MOVES INTO COASTAL NEW ENGLAND
THIS EVENING. INITIALLY EASTERLY GUSTS OF AROUND 20 KT WILL LOWER
AND WINDS OVERALL BECOME LIGHT AND VARIABLE LATER THIS MORNING
BEFORE BECOMING MORE WESTERLY BY THE AFTERNOON...GUSTING 20-25 KT
LATE. THERE IS SOME UNCERTAINTY ON TIMING OF THE SWITCHING
DIRECTIONS AND THE LIGHT AND VARIABLE TRANSITION COULD BE OFF BY
1-2 HOURS AS WELL AS WHEN THE WINDS BECOME WESTERLY.
ICING MAINLY RESTRICTED TO KSWF WHERE THERE IS FREEZING DRIZZLE THIS
MORNING. FOR KSWF...STORM TOTAL SNOW OF ABOUT 7 INCHES WITH ABOUT
A TENTH OF AN INCH OF ICE. ELSEWHERE...THE PRECIP TYPE IS RAIN FOR
EASTERN TERMINALS AND DRIZZLE TO THE WEST. ALL PRECIP BECOMES
DRIZZLE LATER THIS MORNING...LINGERING INTO THE AFTERNOON. MAINLY
IFR CONDITIONS WITH SOME POCKETS OF POSSIBLE LIFR WITH NO
SUBSTANTIAL IMPROVEMENT EXPECTED UNTIL WINDS BECOME MORE WESTERLY
AND START GUSTING LATE IN THE AFTERNOON GENERALLY AFTER 20Z.
POSSIBLE VLIFR POSSIBLE IN FOG THIS MORNING WHEN LOW IS WITHIN
CLOSEST PROXIMITY OF THE TERMINALS. VFR RETURNS BY THE EVENING
WITH WEST WINDS GUSTING TO 25-30 KT...DECREASING A FEW KTS
OVERNIGHT.
NY METRO ENHANCED AVIATION WEATHER SUPPORT...
DETAILED INFORMATION...INCLUDING HOURLY TAF WIND COMPONENT FCSTS
CAN BE FOUND AT: HTTP:/WWW.ERH.NOAA.GOV/ZNY/N90 (LOWER CASE)
KJFK FCSTER COMMENTS: LOW CONFIDENCE WITH VSBYS FORECAST. TIMING
OF IFR VSBYS COULD BE OFF BY A FEW HOURS. HIGH CONFIDENCE WITH
CIGS FORECAST. WIND SHIFT TO NW COULD BE 1-2 HOURS OFF. AMENDMENTS
POSSIBLE.
KLGA FCSTER COMMENTS: LOW CONFIDENCE WITH VSBYS FORECAST. TIMING
OF IFR VSBYS COULD BE OFF BY A FEW HOURS. HIGH CONFIDENCE WITH
CIGS FORECAST. WIND SHIFT TO NW COULD BE 1-2 HOURS OFF. AMENDMENTS
POSSIBLE.
KEWR FCSTER COMMENTS: LOW CONFIDENCE WITH VSBYS FORECAST. TIMING
OF IFR VSBYS COULD BE OFF BY A FEW HOURS. HIGH CONFIDENCE WITH
CIGS FORECAST. WIND SHIFT TO NW COULD BE 1-2 HOURS OFF. AMENDMENTS
POSSIBLE.
THE AFTERNOON KEWR HAZE POTENTIAL FORECAST IS YELLOW...WHICH
IMPLIES SLANT RANGE VISIBILITY 4-6SM OUTSIDE OF CLOUD.
KTEB FCSTER COMMENTS: LOW CONFIDENCE WITH VSBYS FORECAST. TIMING
OF IFR VSBYS COULD BE OFF BY A FEW HOURS. HIGH CONFIDENCE WITH
CIGS FORECAST. WIND SHIFT TO NW COULD BE 1-2 HOURS OFF. AMENDMENTS
POSSIBLE.
KHPN FCSTER COMMENTS: LOW CONFIDENCE WITH VSBYS FORECAST. TIMING
OF IFR VSBYS COULD BE OFF BY A FEW HOURS. HIGH CONFIDENCE WITH
CIGS FORECAST. WIND SHIFT TO NW COULD BE 1-2 HOURS OFF. AMENDMENTS
POSSIBLE.
KISP FCSTER COMMENTS: LOW CONFIDENCE WITH VSBYS FORECAST. TIMING
OF IFR VSBYS COULD BE OFF BY A FEW HOURS. HIGH CONFIDENCE WITH
CIGS FORECAST. WIND SHIFT TO NW COULD BE 1-2 HOURS OFF. AMENDMENTS
POSSIBLE.
.OUTLOOK FOR 12Z WED THROUGH SAT...
.WED...GENERALLY VFR. W WINDS WITH GUSTS INTO THE LOWER 20 KT
RANGE ON WED.
.THU...CHANCE OF SUB-VFR IN LIGHT RAIN OR SNOW.
.FRI...VFR. GUSTY NW WINDS POSSIBLE.
.SAT...VFR.
&&
.MARINE...
MINOR CHANGES THIS UPDATE TO REFLECT THE LATEST TRENDS IN
OBSERVATIONS AND GUIDANCE. FORECAST APPEARS ON TRACK.
NON ELEVATED OBSERVATIONS ACROSS THE COASTAL OCEAN WATERS INDICATE
THAT GALE FORCE GUSTS HAVE COME TO AN END - SO HAVE ALLOWED GALE
WARNING TO COME TO AN END AND HAVE REPLACED IT WITH A SMALL CRAFT
ADVISORY FOR ALL WATERS FOR TODAY. WHILE SHELTERED WATERS...
ESPECIALLY NY HARBOR AND PORTIONS OF W LONG ISLAND SOUND WILL
HAVE PERIODS OF WINDS BELOW SMALL CRAFT LEVELS - EXPECT THEM TO BE
RELATIVELY SHORT IN DURATION.
WINDS INCREASE TONIGHT AS COASTAL LOW DEEPENS TO THE EAST - SO
HAVE ISSUED A GALE WARNING FOR ALL WATERS FOR TONIGHT. GALE GUSTS
CONTINUE ON WEDNESDAY OVER EASTERN COASTAL OCEAN WATERS -
ANZ350-353 - WITH SMALL CRAFT CONDITIONS ELSEWHERE. THE PRESSURE
GRADIENT RELAXES OVER THE REGION WEDNESDAY NIGHT...WITH ALL WATERS
FALLING BELOW SCA LEVELS AFTER MIDNIGHT..AND CONTINUE ON THURSDAY.
WIND GUSTS ON THE COASTAL OCEAN WATERS COULD REACH 25 KT THURSDAY
NIGHT IN THE WAKE OF THE DEPARTING...BUT STRENGTHENING COASTAL
LOW...WITH SUB-SMALL CRAFT CONDITIONS ON THE REMAINDER OF THE WATERS.
FRIDAY WILL FEATURE SUB-SMALL CRAFT CONDITIONS ON ALL WATERS AS THE
PRESSURE GRADIENT RELAXES...EXCEPT FOR POSSIBLY SWELLS BRING SCA
SEAS TO THE TWO EASTERN COASTAL WATER ZONES.
GENERALLY EXPECTING SUB-SCA CONDITIONS THIS WEEKEND WITH HIGH
PRESSURE BUILDING INTO THE REGION. A BRIEF PERIOD OF INTERACTION
BETWEEN THE DEPARTING LOW AND APPROACHING HIGH FRI NIGHT COULD
INCREASE WINDS ENOUGH FROM THE NORTHWEST...COMBINED WITH COLD AIR
ADVECTION TO PRODUCE 25 KT GUSTS AND 5 FT SEAS ON THE OCEAN.
CONDITIONS THEN WILL DIMINISH BY SATURDAY.
POSSIBLE SCA CONDITIONS AGAIN NEXT MONDAY AND TUESDAY WITH THE NEXT
LOW PRESSURE SYSTEM.
&&
.HYDROLOGY...
LIQUID EQUIVALENT STORM TOTAL QPF OF 1.00-1.25 INCHES EXPECTED.
PRECIP LIGHT ENOUGH AT THIS TIME THAT COMBINED LIGHT RAIN AND SNOW
MELT SHOULD NOT CAUSE MUCH IN THE WAY OF PROBLEMS.
DRY TONIGHT AND WEDNESDAY. THERE IS THE CHANCE FOR SOME LIGHT
PRECIPITATION FROM LATE WEDNESDAY NIGHT INTO THURSDAY EVENING
MAINLY OVER THE SE 1/2 OF THE TRI-STATE. NO HYDROLOGIC IMPACT
IS EXPECTED.
&&
.OKX WATCHES/WARNINGS/ADVISORIES...
CT...WINTER STORM WARNING UNTIL 10 AM EDT THIS MORNING FOR
CTZ005>008.
NY...WINTER STORM WARNING UNTIL 10 AM EDT THIS MORNING FOR
NYZ067>070.
NJ...WINTER STORM WARNING UNTIL 10 AM EDT THIS MORNING FOR NJZ002.
MARINE...SMALL CRAFT ADVISORY UNTIL 6 PM EDT THIS EVENING FOR ANZ330-
335-338-340-345-350-353-355.
GALE WARNING FROM 6 PM THIS EVENING TO 6 AM EDT WEDNESDAY FOR
ANZ330-335-338-340-345-355.
GALE WARNING FROM 6 PM THIS EVENING TO 6 PM EDT WEDNESDAY FOR
ANZ350-353.
&&
$$
SYNOPSIS...GOODMAN/MALOIT/SEARS
NEAR TERM...MALOIT/GOODMAN
SHORT TERM...MALOIT
LONG TERM...SEARS
AVIATION...JM
MARINE...MALOIT/SEARS
HYDROLOGY...GOODMAN
AREA FORECAST DISCUSSION
NWS NEW YORK NY
603 AM EDT TUE MAR 19 2013
.SYNOPSIS...
A COASTAL LOW WILL PASS JUST SOUTH OF LONG ISLAND TODAY...THEN
MOVE FROM THE GULF OF MAINE TONIGHT INTO THE CANADIAN MARITIMES ON
WEDNESDAY. ANOTHER COASTAL LOW WILL DEVELOP OFF THE MID ATLANTIC
COAST WEDNESDAY NIGHT...AND TRACK WELL SOUTHEAST OF LONG ISLAND
THURSDAY AND WELL EAST OF CAPE COD THURSDAY NIGHT. WEAK HIGH
PRESSURE WILL BUILD IN ON FRIDAY AND REMAIN THROUGH THE WEEKEND.
LOW PRESSURE WILL PASS TO THE SOUTH EARLY NEXT WEEK.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
LOW PRESSURE IS NOW OFF THE SRN NJ COAST...AND LOOKS TO PASS JUST
S OF LONG ISLAND TOWARD NANTUCKET TODAY PER GREATEST 3-HOURLY
PRESSURE FALLS. MID LEVEL WARMING HAS FORCED P-TYPE OVER TO EITHER
RAIN OR FREEZING RAIN. LOW LEVEL WARMING ON E FLOW HAS CHANGED
PRECIP TO RAIN ALONG THE COAST AND IN NYC METRO...SO MOST
ADVISORIES IN THIS AREA WERE DROPPED EARLIER EXCEPT IN WESTERN
BERGEN/E PASSAIC... WHERE SOME FREEZING RAIN MAY OCCUR AS TEMPS
HOVER AROUND FREEZING FOR A WHILE.
AS FOR THE INTERIOR...SFC TEMPS REMAIN AT OR BELOW FREEZING...AND
FREEZING RAIN THERE COULD ACCRETE TO 1-2 TENTHS OF AN INCH. MANY
LOWER HUDSON VALLEY LOCATIONS HAVE ALREADY HAD UP TO 6 INCHES OF
SNOW...WHILE MOST OF SRN CT HAS SEEN 3-4 INCHES OF SNOWFALL. COMBO
OF ICE ATOP EARLIER SNOWFALL STILL COMMUTE JUSTIFIES KEEPING
WINTER STORM WARNINGS UP ACROSS THE INTERIOR BASED ON IMPACT.
PRECIP HAS BECOME MORE SPOTTY IN NATURE AT THIS TIME ACROSS
WESTERN SECTIONS...BUT MAY FILL IN AGAIN DURING THE MORNING AND
EARLY AFTERNOON AS A POTENT MID LEVEL VORTICITY MAX ROUNDS THE
BASE OF A CLOSED LOW CENTERED OVER THE UPPER GREAT LAKES AND MOVES
ACROSS THE LOCAL AREA. AFTER THIS VORTICITY PASSES...PRECIP SHOULD
END AND SKIES MAY BRIGHTEN DURING THE MID TO LATE AFTERNOON ON A
BRISK DOWNSLOPE W FLOW ACROSS NYC METRO AND THE LOWER HUDSON
VALLEY.
FOR HIGH TEMPS...BLENDED MAV/MET WITH COLDER 04Z RAP 2M
TEMPS...WITH HIGHS ONLY NEAR 40 INLAND WHICH COULD STILL BE A
LITTLE GENEROUS ESPECIALLY ACROSS SRN CT...AND MID 40S FOR NYC
METRO AND LONG ISLAND.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH FRIDAY/...
FAST W TO WSW FLOW ALOFT TONIGHT AND THURSDAY AS CLOSED LOW BUILDS
INTO NORTHERN NEW ENGLAND...THEN SE CANADA. SHOULD BE DRY TONIGHT
AND THURSDAY WITH LITTLE IF ANY IN THE WAY OF FORCING - HOWEVER IF
UPPER TROUGH AXIS IS A TAD SLOWER IN PUSHING THROUGH THAN CURRENTLY
FORECAST COULD SEE SOME -SHSN ACROSS NORTHERN ZONES EARLY THIS
EVENING. FOR LOWS TONIGHT USED A BLEND OF MAV/MET GUIDANCE WITH
VALUES FORECAST TO BE A FEW DEGREES ABOVE NORMAL. USED A BLEND OF
MAV/MET GUIDANCE WITH NAM 2-METER TEMPERATURES AND A MIX DOWN FROM
850 HPA NEAR THE IMMEDIATE COAST...800 HPA ACROSS FAR INTERIOR
AREAS AND 825 HPA IN BETWEEN. THIS YIELDS HIGHS AROUND 10 DEGREES
BELOW NORMAL.
A COASTAL LOW DEVELOPS OFF THE MID ATLANTIC COAST WEDNESDAY NIGHT IN
RESPONSE TO A SOUTHERN STREAM SHORTWAVE MOVING OFFSHORE - THIS LOW
THEN MOVES WELL SE OF LONG ISLAND THURSDAY AND TO THE E OF CAPE COD
THURSDAY NIGHT AS THE NORTHERN STREAM CUTOFF LOW PIVOTS TO THE SE
INTO THE TRI-STATE. THE RESULT WILL BE CHANCE POPS COASTAL
AREAS/SLIGHT CHANCE POPS ELSEWHERE FOR LIGHT SNOW FROM LATE
WEDNESDAY NIGHT INTO THURSDAY EVENING - EXCEPT OVER FAR NW ZONES
WHERE ONLY COULD SEE A FEW FLURRIES.
USED A BLEND OF MAV/MET GUIDANCE FOR LOWS WEDNESDAY NIGHT WITH
VALUES FORECAST TO BE AROUND 5 DEGREES BELOW NORMAL. U SED A
BLEND OF MIXING DOWN FROM 850 HPA NEAR THE COAST...800 HPA WELL
INLAND...AND 825 HPA IN BETWEEN...WITH A BLEND OF MAV/MET
GUIDANCE...AND NAM AND ECMWF 2-METER TEMPERATURES. THIS YIELDS
VALUES 10-15 DEGREES BELOW NORMAL. FOR LOWS THURSDAY NIGHT USED A
BLEND OF MEX/MEX ENSEMBLE MEAN/ECE/WPC GUIDANCE WITH VALUES AROUND
5 DEGREES BELOW NORMAL.
NW FLOW ALOFT FRIDAY WITH UPPER LOW OVER N AND E NEW ENGLAND - COULD
GET ENOUGH FORCING OUT OUT OF A PASSING SHORTWAVE IN THE AFTERNOON
TO WARRANT SLIGHT CHANCE POPS FOR -SHSN/-SHRA OVER FAR NW ZONES. FOR
HIGHS USED A BLEND OF MEX/MEX ENSEMBLE MEAN/ECE/WPC GUIDANCE WITH
VALUES AROUND 10 DEGREES BELOW NORMAL.
&&
.LONG TERM /FRIDAY NIGHT THROUGH MONDAY/...
MODELS BEGINNING TO COME INTO BETTER AGREEMENT WITH THE HANDLING
AND TIMING OF HIGH PRESSURE SYSTEM OVER THE COMING WEEKEND...AND
THE NEXT LOW PRESSURE SYSTEM FOR NEXT MONDAY/TUESDAY.
HIGH PRESSURE BUILDS TO THE SOUTH OVER THE NORTHEAST SATURDAY INTO
SUNDAY UNDER A BROAD UPPER LEVEL TROUGH. MULTIPLE SHORTWAVES
EXPECTED TO PASS THROUGH THE REGION WHILE ROTATING AROUND THE MAIN
UPPER LEVEL CLOSED LOW. DESPITE DECENT FORCING ASSOCIATED WITH EACH
PASSING WAVE...A PERSISTENT NORTHWESTERLY FLOW WILL KEEP A MAINLY
DRY VERTICAL COLUMN...RESULTING IN DRY CONDITIONS ACROSS THE AREA.
WHILE THE 12Z/18 RUNS HAD MUCH HIGHER DISCREPANCIES IN THE HANDLING
OF THE NEXT LOW...THE 00Z/19 RUNS ARE STARTING TO COME INTO BETTER
ALIGNMENT BUT STILL WITH SOME DIFFERENCES. LOW PRESSURE FORMS OVER
THE CENTRAL STATES ON SUNDAY...PROGRESSING TO THE EAST TO BEGIN
THE WEEK. 00Z ECMWF ACTUALLY THE MORE PROGRESSIVE OF THE SOLUTIONS...
WITH THE GFS LAGGING BEHIND WHILE DEVELOPING A SECONDARY LOW. THE
GFS THEN KEEPS THE UPPER LEVEL LOW FROM OVER THE WEEKEND NEARLY
STATIONARY...ALLOWING FOR POSSIBLE INTERACTION WITH THE NEXT LOW
TRAVERSING THE CENTRAL US...RESULTING IN MORE WIDESPREAD
PRECIPITATION. HOWEVER...THE PATTERN OF THE ECMWF KEEPS THE
TRAVERSING LOW TO THE SOUTH...BUILDING IN SUBSIDENCE OVER MOST OF
THE NORTHEAST...KEEPING THE HEAVIEST PRECIPITATION TO THE SOUTH.
BECAUSE OF THE MODEL SPREAD...CONTINUED THE SLIGHT CHANCE POPS FOR
MONDAY INTO TUESDAY.
GENERALLY USED A BLEND OF THE WPC AND MOS GUIDANCE FOR TEMPS THIS
WEEKEND INTO NEXT WEEK...WHICH KEEPS HIGH TEMPS SLIGHTLY BELOW
NORMAL AND OVERNIGHT LOWS RIGHT AROUND TO SLIGHTLY BELOW NORMAL.
&&
.AVIATION /10Z TUESDAY THROUGH SATURDAY/...
LOW PRESSURE WILL TRACK FROM THE DELMARVA TO JUST SOUTHEAST OF
NYC THIS MORNING. THE LOW PRESSURE MOVES INTO COASTAL NEW ENGLAND
THIS EVENING. INITIALLY EASTERLY GUSTS OF AROUND 20 KT WILL LOWER
AND WINDS OVERALL BECOME LIGHT AND VARIABLE THIS MORNING BEFORE
BECOMING MORE WESTERLY BY THE AFTERNOON...GUSTING 20-25 KT LATE.
THERE IS SOME UNCERTAINTY ON WHEN EXACTLY THE WINDS TURN MORE
WESTERLY AND THE TIMING COULD BE OFF BY 1-2 HOURS.
ICING MAINLY RESTRICTED TO KSWF WHERE SNOW WILL BE CHANGING TO
SLEET AND FREEZING RAIN THIS MORNING. FOR KSWF...LOOKING FOR STORM
TOTAL SNOW OF ABOUT 7 INCHES WITH ABOUT A TENTH OF AN INCH OF ICE.
ELSEWHERE...THE PRECIP TYPE IS RAIN. ALL PRECIP BECOMES DRIZZLE
LATER THIS MORNING...LINGERING INTO THE AFTERNOON. MAINLY MVFR/IFR
CONDITIONS WITH SOME POCKETS OF LIFR WITH NO SUBSTANTIAL
IMPROVEMENT EXPECTED UNTIL WINDS BECOME MORE WESTERLY AND START
GUSTING LATE IN THE AFTERNOON GENERALLY AFTER 20Z. POSSIBLE VLIFR
POSSIBLE IN FOG THIS MORNING WHEN LOW IS WITHIN CLOSEST PROXIMITY
OF THE TERMINALS. VFR RETURNS BY THE EVENING WITH WEST WINDS
GUSTING TO 25-30 KT.
NY METRO ENHANCED AVIATION WEATHER SUPPORT...
DETAILED INFORMATION...INCLUDING HOURLY TAF WIND COMPONENT FCSTS
CAN BE FOUND AT: HTTP:/WWW.ERH.NOAA.GOV/ZNY/N90 (LOWER CASE)
KJFK FCSTER COMMENTS: THE TIMING OF IFR VSBYS AND LIFR CIGS COULD
BE OFF BY 1-3 HOURS. WIND SHIFT TO NW COULD BE 1-2 HOURS OFF.
AMENDMENTS POSSIBLE.
KLGA FCSTER COMMENTS: THE TIMING OF IFR VSBYS AND LIFR CIGS COULD
BE OFF BY 1-3 HOURS. WIND SHIFT TO NW COULD BE 1-2 HOURS OFF.
AMENDMENTS POSSIBLE.
KEWR FCSTER COMMENTS: THE TIMING OF IFR VSBYS AND LIFR CIGS COULD
BE OFF BY 1-3 HOURS. WIND SHIFT TO NW COULD BE 1-2 HOURS OFF.
AMENDMENTS POSSIBLE.
THE AFTERNOON KEWR HAZE POTENTIAL FORECAST IS YELLOW...WHICH
IMPLIES SLANT RANGE VISIBILITY 4-6SM OUTSIDE OF CLOUD.
KTEB FCSTER COMMENTS: THE TIMING OF IFR VSBYS AND LOW END IFR
CIGS COULD BE OFF BY 1-3 HOURS. WIND SHIFT TO NW COULD BE 1-2
HOURS OFF. AMENDMENTS POSSIBLE.
KHPN FCSTER COMMENTS: THE TIMING OF LIFR CONDITIONS COULD BE OFF
BY 1-3 HOURS. WIND SHIFT TO NW COULD BE 1-2 HOURS OFF. AMENDMENTS
POSSIBLE.
KISP FCSTER COMMENTS: THE TIMING OF IFR VSBYS AND LIFR CIGS
COULD BE OFF BY 1-3 HOURS. WIND SHIFT TO NW COULD BE 1-2 HOURS
OFF. AMENDMENTS POSSIBLE.
.OUTLOOK FOR 09Z WED THROUGH SAT...
.WED...GENERALLY VFR. W WINDS WITH GUSTS INTO THE LOWER 20 KT
RANGE ON WED.
.THU...CHANCE OF SUB-VFR IN LIGHT RAIN OR SNOW.
.FRI...VFR. GUSTY NW WINDS POSSIBLE.
.SAT...VFR.
&&
.MARINE...
NON ELEVATED OBSERVATIONS ACROSS THE COASTAL OCEAN WATERS INDICATE
THAT GALE FORCE GUSTS HAVE COME TO AN END - SO HAVE ALLOWED GALE
WARNING TO COME TO AN END AND HAVE REPLACED IT WITH A SMALL CRAFT
ADVISORY FOR ALL WATERS FOR TODAY. WHILE SHELTERED WATERS...
ESPECIALLY NY HARBOR AND PORTIONS OF W LONG ISLAND SOUND WILL
HAVE PERIODS OF WINDS BELOW SMALL CRAFT LEVELS - EXPECT THEM TO BE
RELATIVELY SHORT IN DURATION.
WINDS INCREASE TONIGHT AS COASTAL LOW DEEPENS TO THE EAST - SO
HAVE ISSUED A GALE WARNING FOR ALL WATERS FOR TONIGHT. GALE GUSTS
CONTINUE ON WEDNESDAY OVER EASTERN COASTAL OCEAN WATERS -
ANZ350-353 - WITH SMALL CRAFT CONDITIONS ELSEWHERE. THE PRESSURE
GRADIENT RELAXES OVER THE REGION WEDNESDAY NIGHT...WITH ALL WATERS
FALLING BELOW SCA LEVELS AFTER MIDNIGHT..AND CONTINUE ON THURSDAY.
WIND GUSTS ON THE COASTAL OCEAN WATERS COULD REACH 25 KT THURSDAY
NIGHT IN THE WAKE OF THE DEPARTING...BUT STRENGTHENING COASTAL
LOW...WITH SUB-SMALL CRAFT CONDITIONS ON THE REMAINDER OF THE WATERS.
FRIDAY WILL FEATURE SUB-SMALL CRAFT CONDITIONS ON ALL WATERS AS THE
PRESSURE GRADIENT RELAXES...EXCEPT FOR POSSIBLY SWELLS BRING SCA
SEAS TO THE TWO EASTERN COASTAL WATER ZONES.
GENERALLY EXPECTING SUB-SCA CONDITIONS THIS WEEKEND WITH HIGH
PRESSURE BUILDING INTO THE REGION. A BRIEF PERIOD OF INTERACTION
BETWEEN THE DEPARTING LOW AND APPROACHING HIGH FRI NIGHT COULD
INCREASE WINDS ENOUGH FROM THE NORTHWEST...COMBINED WITH COLD AIR
ADVECTION TO PRODUCE 25 KT GUSTS AND 5 FT SEAS ON THE OCEAN.
CONDITIONS THEN WILL DIMINISH BY SATURDAY.
POSSIBLE SCA CONDITIONS AGAIN NEXT MONDAY AND TUESDAY WITH THE NEXT
LOW PRESSURE SYSTEM.
&&
.HYDROLOGY...
LIQUID EQUIVALENT STORM TOTAL QPF OF 1.00-1.25 INCHES EXPECTED.
PRECIP LIGHT ENOUGH AT THIS TIME THAT COMBINED LIGHT RAIN AND SNOW
MELT SHOULD NOT CAUSE MUCH IN THE WAY OF PROBLEMS.
DRY TONIGHT AND WEDNESDAY. THERE IS THE CHANCE FOR SOME LIGHT
PRECIPITATION FROM LATE WEDNESDAY NIGHT INTO THURSDAY EVENING
MAINLY OVER THE SE 1/2 OF THE TRI-STATE. NO HYDROLOGIC IMPACT
IS EXPECTED.
&&
.OKX WATCHES/WARNINGS/ADVISORIES...
CT...WINTER STORM WARNING UNTIL 10 AM EDT THIS MORNING FOR
CTZ005>008.
NY...WINTER STORM WARNING UNTIL 10 AM EDT THIS MORNING FOR
NYZ067>070.
NJ...WINTER STORM WARNING UNTIL 10 AM EDT THIS MORNING FOR NJZ002.
WINTER WEATHER ADVISORY UNTIL 10 AM EDT THIS MORNING FOR
NJZ004-103.
MARINE...SMALL CRAFT ADVISORY UNTIL 6 PM EDT THIS EVENING FOR ANZ330-
335-338-340-345-350-353-355.
GALE WARNING FROM 6 PM THIS EVENING TO 6 AM EDT WEDNESDAY FOR
ANZ330-335-338-340-345-355.
GALE WARNING FROM 6 PM THIS EVENING TO 6 PM EDT WEDNESDAY FOR
ANZ350-353.
&&
$$
SYNOPSIS...GOODMAN/MALOIT/SEARS
NEAR TERM...GOODMAN
SHORT TERM...MALOIT
LONG TERM...SEARS
AVIATION...JM
MARINE...MALOIT/SEARS
HYDROLOGY...GOODMAN
AREA FORECAST DISCUSSION
NWS NEW YORK NY
558 AM EDT TUE MAR 19 2013
.SYNOPSIS...
A COASTAL LOW WILL PASS JUST SOUTH OF LONG ISLAND TODAY...THEN
MOVE FROM THE GULF OF MAINE TONIGHT INTO THE CANADIAN MARITIMES ON
WEDNESDAY. ANOTHER COASTAL LOW WILL DEVELOP OFF THE MID ATLANTIC
COAST WEDNESDAY NIGHT...AND TRACK WELL SOUTHEAST OF LONG ISLAND
THURSDAY AND WELL EAST OF CAPE COD THURSDAY NIGHT. WEAK HIGH
PRESSURE WILL BUILD IN ON FRIDAY AND REMAIN THROUGH THE WEEKEND.
LOW PRESSURE WILL PASS TO THE SOUTH EARLY NEXT WEEK.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
LOW PRESSURE IS NOW OFF THE SRN NJ COAST...AND LOOKS TO PASS JUST
S OF LONG ISLAND TOWARD NANTUCKET TODAY PER GREATEST 3-HOURLY
PRESSURE FALLS. MID LEVEL WARMING HAS FORCED P-TYPE OVER TO EITHER
RAIN OR FREEZING RAIN. LOW LEVEL WARMING ON E FLOW HAS CHANGED
PRECIP TO RAIN ALONG THE COAST AND IN NYC METRO...SO MOST
ADVISORIES IN THIS AREA WERE DROPPED EARLIER EXCEPT IN WESTERN
BERGEN/E PASSAIC... WHERE SOME FREEZING RAIN MAY OCCUR AS TEMPS
HOVER AROUND FREEZING FOR A WHILE.
AS FOR THE INTERIOR...SFC TEMPS REMAIN AT OR BELOW FREEZING...AND
FREEZING RAIN THERE COULD ACCRETE TO 1-2 TENTHS OF AN INCH. MANY
LOWER HUDSON VALLEY LOCATIONS HAVE ALREADY HAD UP TO 6 INCHES OF
SNOW...WHILE MOST OF SRN CT HAS SEEN 3-4 INCHES OF SNOWFALL. COMBO
OF ICE ATOP EARLIER SNOWFALL STILL COMMUTE JUSTIFIES KEEPING
WINTER STORM WARNINGS UP ACROSS THE INTERIOR BASED ON IMPACT.
PRECIP HAS BECOME MORE SPOTTY IN NATURE AT THIS TIME ACROSS
WESTERN SECTIONS...BUT MAY FILL IN AGAIN DURING THE MORNING AND
EARLY AFTERNOON AS A POTENT MID LEVEL VORTICITY MAX ROUNDS THE
BASE OF A CLOSED LOW CENTERED OVER THE UPPER GREAT LAKES AND MOVES
ACROSS THE LOCAL AREA. AFTER THIS VORTICITY PASSES...PRECIP SHOULD
END AND SKIES MAY BRIGHTEN DURING THE MID TO LATE AFTERNOON ON A
BRISK DOWNSLOPE W FLOW ACROSS NYC METRO AND THE LOWER HUDSON
VALLEY.
FOR HIGH TEMPS...BLENDED MAV/MET WITH COLDER 04Z RAP 2M
TEMPS...WITH HIGHS ONLY NEAR 40 INLAND WHICH COULD STILL BE A
LITTLE GENEROUS ESPECIALLY ACROSS SRN CT...AND MID 40S FOR NYC
METRO AND LONG ISLAND.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH FRIDAY/...
FAST W TO WSW FLOW ALOFT TONIGHT AND THURSDAY AS CLOSED LOW BUILDS
INTO NORTHERN NEW ENGLAND...THEN SE CANADA. SHOULD BE DRY TONIGHT
AND THURSDAY WITH LITTLE IF ANY IN THE WAY OF FORCING - HOWEVER IF
UPPER TROUGH AXIS IS A TAD SLOWER IN PUSHING THROUGH THAN CURRENTLY
FORECAST COULD SEE SOME -SHSN ACROSS NORTHERN ZONES EARLY THIS
EVENING. FOR LOWS TONIGHT USED A BLEND OF MAV/MET GUIDANCE WITH
VALUES FORECAST TO BE A FEW DEGREES ABOVE NORMAL. USED A BLEND OF
MAV/MET GUIDANCE WITH NAM 2-METER TEMPERATURES AND A MIX DOWN FROM
850 HPA NEAR THE IMMEDIATE COAST...800 HPA ACROSS FAR INTERIOR
AREAS AND 825 HPA IN BETWEEN. THIS YIELDS HIGHS AROUND 10 DEGREES
BELOW NORMAL.
A COASTAL LOW DEVELOPS OFF THE MID ATLANTIC COAST WEDNESDAY NIGHT IN
RESPONSE TO A SOUTHERN STREAM SHORTWAVE MOVING OFFSHORE - THIS LOW
THEN MOVES WELL SE OF LONG ISLAND THURSDAY AND TO THE E OF CAPE COD
THURSDAY NIGHT AS THE NORTHERN STREAM CUTOFF LOW PIVOTS TO THE SE
INTO THE TRI-STATE. THE RESULT WILL BE CHANCE POPS COASTAL
AREAS/SLIGHT CHANCE POPS ELSEWHERE FOR LIGHT SNOW FROM LATE
WEDNESDAY NIGHT INTO THURSDAY EVENING - EXCEPT OVER FAR NW ZONES
WHERE ONLY COULD SEE A FEW FLURRIES.
USED A BLEND OF MAV/MET GUIDANCE FOR LOWS WEDNESDAY NIGHT WITH
VALUES FORECAST TO BE AROUND 5 DEGREES BELOW NORMAL. U SED A
BLEND OF MIXING DOWN FROM 850 HPA NEAR THE COAST...800 HPA WELL
INLAND...AND 825 HPA IN BETWEEN...WITH A BLEND OF MAV/MET
GUIDANCE...AND NAM AND ECMWF 2-METER TEMPERATURES. THIS YIELDS
VALUES 10-15 DEGREES BELOW NORMAL. FOR LOWS THURSDAY NIGHT USED A
BLEND OF MEX/MEX ENSEMBLE MEAN/ECE/WPC GUIDANCE WITH VALUES AROUND
5 DEGREES BELOW NORMAL.
NW FLOW ALOFT FRIDAY WITH UPPER LOW OVER N AND E NEW ENGLAND - COULD
GET ENOUGH FORCING OUT OUT OF A PASSING SHORTWAVE IN THE AFTERNOON
TO WARRANT SLIGHT CHANCE POPS FOR -SHSN/-SHRA OVER FAR NW ZONES. FOR
HIGHS USED A BLEND OF MEX/MEX ENSEMBLE MEAN/ECE/WPC GUIDANCE WITH
VALUES AROUND 10 DEGREES BELOW NORMAL.
&&
.LONG TERM /FRIDAY NIGHT THROUGH MONDAY/...
MODELS BEGINNING TO COME INTO BETTER AGREEMENT WITH THE HANDLING
AND TIMING OF HIGH PRESSURE SYSTEM OVER THE COMING WEEKEND...AND
THE NEXT LOW PRESSURE SYSTEM FOR NEXT MONDAY/TUESDAY.
HIGH PRESSURE BUILDS TO THE SOUTH OVER THE NORTHEAST SATURDAY INTO
SUNDAY UNDER A BROAD UPPER LEVEL TROUGH. MULTIPLE SHORTWAVES
EXPECTED TO PASS THROUGH THE REGION WHILE ROTATING AROUND THE MAIN
UPPER LEVEL CLOSED LOW. DESPITE DECENT FORCING ASSOCIATED WITH EACH
PASSING WAVE...A PERSISTENT NORTHWESTERLY FLOW WILL KEEP A MAINLY
DRY VERTICAL COLUMN...RESULTING IN DRY CONDITIONS ACROSS THE AREA.
WHILE THE 12Z/18 RUNS HAD MUCH HIGHER DISCREPANCIES IN THE HANDLING
OF THE NEXT LOW...THE 00Z/19 RUNS ARE STARTING TO COME INTO BETTER
ALIGNMENT BUT STILL WITH SOME DIFFERENCES. LOW PRESSURE FORMS OVER
THE CENTRAL STATES ON SUNDAY...PROGRESSING TO THE EAST TO BEGIN
THE WEEK. 00Z ECMWF ACTUALLY THE MORE PROGRESSIVE OF THE SOLUTIONS...
WITH THE GFS LAGGING BEHIND WHILE DEVELOPING A SECONDARY LOW. THE
GFS THEN KEEPS THE UPPER LEVEL LOW FROM OVER THE WEEKEND NEARLY
STATIONARY...ALLOWING FOR POSSIBLE INTERACTION WITH THE NEXT LOW
TRAVERSING THE CENTRAL US...RESULTING IN MORE WIDESPREAD
PRECIPITATION. HOWEVER...THE PATTERN OF THE ECMWF KEEPS THE
TRAVERSING LOW TO THE SOUTH...BUILDING IN SUBSIDENCE OVER MOST OF
THE NORTHEAST...KEEPING THE HEAVIEST PRECIPITATION TO THE SOUTH.
BECAUSE OF THE MODEL SPREAD...CONTINUED THE SLIGHT CHANCE POPS FOR
MONDAY INTO TUESDAY.
GENERALLY USED A BLEND OF THE WPC AND MOS GUIDANCE FOR TEMPS THIS
WEEKEND INTO NEXT WEEK...WHICH KEEPS HIGH TEMPS SLIGHTLY BELOW
NORMAL AND OVERNIGHT LOWS RIGHT AROUND TO SLIGHTLY BELOW NORMAL.
&&
.AVIATION /10Z TUESDAY THROUGH SATURDAY/...
LOW PRESSURE WILL TRACK FROM THE DELMARVA TO JUST SOUTHEAST OF
NYC THIS MORNING. THE LOW PRESSURE MOVES INTO COASTAL NEW ENGLAND
THIS EVENING. INITIALLY EASTERLY GUSTS OF AROUND 20 KT WILL LOWER
AND WINDS OVERALL BECOME LIGHT AND VARIABLE THIS MORNING BEFORE
BECOMING MORE WESTERLY BY THE AFTERNOON...GUSTING 20-25 KT LATE.
THERE IS SOME UNCERTAINTY ON WHEN EXACTLY THE WINDS TURN MORE
WESTERLY AND THE TIMING COULD BE OFF BY 1-2 HOURS.
ICING MAINLY RESTRICTED TO KSWF WHERE SNOW WILL BE CHANGING TO
SLEET AND FREEZING RAIN THIS MORNING. ELSEWHERE...THE PRECIP TYPE
IS RAIN. ALL PRECIP BECOMES DRIZZLE LATER THIS MORNING...LINGERING
INTO THE AFTERNOON. MAINLY MVFR/IFR CONDITIONS WITH SOME POCKETS
OF LIFR WITH NO SUBSTANTIAL IMPROVEMENT EXPECTED UNTIL WINDS
BECOME MORE WESTERLY AND START GUSTING LATE IN THE AFTERNOON
GENERALLY AFTER 20Z. POSSIBLE VLIFR POSSIBLE IN FOG THIS MORNING
WHEN LOW IS WITHIN CLOSEST PROXIMITY OF THE TERMINALS. VFR RETURNS
BY THE EVENING WITH WEST WINDS GUSTING TO 25-30 KT.
NY METRO ENHANCED AVIATION WEATHER SUPPORT...
DETAILED INFORMATION...INCLUDING HOURLY TAF WIND COMPONENT FCSTS
CAN BE FOUND AT: HTTP:/WWW.ERH.NOAA.GOV/ZNY/N90 (LOWER CASE)
KJFK FCSTER COMMENTS: THE TIMING OF IFR VSBYS AND LIFR CIGS COULD
BE OFF BY 1-3 HOURS. WIND SHIFT TO NW COULD BE 1-2 HOURS OFF.
AMENDMENTS POSSIBLE.
KLGA FCSTER COMMENTS: THE TIMING OF IFR VSBYS AND LIFR CIGS COULD
BE OFF BY 1-3 HOURS. WIND SHIFT TO NW COULD BE 1-2 HOURS OFF.
AMENDMENTS POSSIBLE.
KEWR FCSTER COMMENTS: THE TIMING OF IFR VSBYS AND LIFR CIGS COULD
BE OFF BY 1-3 HOURS. WIND SHIFT TO NW COULD BE 1-2 HOURS OFF.
AMENDMENTS POSSIBLE.
THE AFTERNOON KEWR HAZE POTENTIAL FORECAST IS YELLOW...WHICH
IMPLIES SLANT RANGE VISIBILITY 4-6SM OUTSIDE OF CLOUD.
KTEB FCSTER COMMENTS: THE TIMING OF IFR VSBYS AND LOW END IFR
CIGS COULD BE OFF BY 1-3 HOURS. WIND SHIFT TO NW COULD BE 1-2
HOURS OFF. AMENDMENTS POSSIBLE.
KHPN FCSTER COMMENTS: THE TIMING OF LIFR CONDITIONS COULD BE OFF
BY 1-3 HOURS. WIND SHIFT TO NW COULD BE 1-2 HOURS OFF. AMENDMENTS
POSSIBLE.
KISP FCSTER COMMENTS: THE TIMING OF IFR VSBYS AND LIFR CIGS
COULD BE OFF BY 1-3 HOURS. WIND SHIFT TO NW COULD BE 1-2 HOURS
OFF. AMENDMENTS POSSIBLE.
.OUTLOOK FOR 09Z WED THROUGH SAT...
.WED...GENERALLY VFR. W WINDS WITH GUSTS INTO THE LOWER 20 KT
RANGE ON WED.
.THU...CHANCE OF SUB-VFR IN LIGHT RAIN OR SNOW.
.FRI...VFR. GUSTY NW WINDS POSSIBLE.
.SAT...VFR.
&&
.MARINE...
NON ELEVATED OBSERVATIONS ACROSS THE COASTAL OCEAN WATERS INDICATE
THAT GALE FORCE GUSTS HAVE COME TO AN END - SO HAVE ALLOWED GALE
WARNING TO COME TO AN END AND HAVE REPLACED IT WITH A SMALL CRAFT
ADVISORY FOR ALL WATERS FOR TODAY. WHILE SHELTERED WATERS...
ESPECIALLY NY HARBOR AND PORTIONS OF W LONG ISLAND SOUND WILL
HAVE PERIODS OF WINDS BELOW SMALL CRAFT LEVELS - EXPECT THEM TO BE
RELATIVELY SHORT IN DURATION.
WINDS INCREASE TONIGHT AS COASTAL LOW DEEPENS TO THE EAST - SO
HAVE ISSUED A GALE WARNING FOR ALL WATERS FOR TONIGHT. GALE GUSTS
CONTINUE ON WEDNESDAY OVER EASTERN COASTAL OCEAN WATERS -
ANZ350-353 - WITH SMALL CRAFT CONDITIONS ELSEWHERE. THE PRESSURE
GRADIENT RELAXES OVER THE REGION WEDNESDAY NIGHT...WITH ALL WATERS
FALLING BELOW SCA LEVELS AFTER MIDNIGHT..AND CONTINUE ON THURSDAY.
WIND GUSTS ON THE COASTAL OCEAN WATERS COULD REACH 25 KT THURSDAY
NIGHT IN THE WAKE OF THE DEPARTING...BUT STRENGTHENING COASTAL
LOW...WITH SUB-SMALL CRAFT CONDITIONS ON THE REMAINDER OF THE WATERS.
FRIDAY WILL FEATURE SUB-SMALL CRAFT CONDITIONS ON ALL WATERS AS THE
PRESSURE GRADIENT RELAXES...EXCEPT FOR POSSIBLY SWELLS BRING SCA
SEAS TO THE TWO EASTERN COASTAL WATER ZONES.
GENERALLY EXPECTING SUB-SCA CONDITIONS THIS WEEKEND WITH HIGH
PRESSURE BUILDING INTO THE REGION. A BRIEF PERIOD OF INTERACTION
BETWEEN THE DEPARTING LOW AND APPROACHING HIGH FRI NIGHT COULD
INCREASE WINDS ENOUGH FROM THE NORTHWEST...COMBINED WITH COLD AIR
ADVECTION TO PRODUCE 25 KT GUSTS AND 5 FT SEAS ON THE OCEAN.
CONDITIONS THEN WILL DIMINISH BY SATURDAY.
POSSIBLE SCA CONDITIONS AGAIN NEXT MONDAY AND TUESDAY WITH THE NEXT
LOW PRESSURE SYSTEM.
&&
.HYDROLOGY...
LIQUID EQUIVALENT STORM TOTAL QPF OF 1.00-1.25 INCHES EXPECTED.
PRECIP LIGHT ENOUGH AT THIS TIME THAT COMBINED LIGHT RAIN AND SNOW
MELT SHOULD NOT CAUSE MUCH IN THE WAY OF PROBLEMS.
DRY TONIGHT AND WEDNESDAY. THERE IS THE CHANCE FOR SOME LIGHT
PRECIPITATION FROM LATE WEDNESDAY NIGHT INTO THURSDAY EVENING
MAINLY OVER THE SE 1/2 OF THE TRI-STATE. NO HYDROLOGIC IMPACT
IS EXPECTED.
&&
.OKX WATCHES/WARNINGS/ADVISORIES...
CT...WINTER STORM WARNING UNTIL 10 AM EDT THIS MORNING FOR
CTZ005>008.
NY...WINTER STORM WARNING UNTIL 10 AM EDT THIS MORNING FOR
NYZ067>070.
NJ...WINTER STORM WARNING UNTIL 10 AM EDT THIS MORNING FOR NJZ002.
WINTER WEATHER ADVISORY UNTIL 10 AM EDT THIS MORNING FOR
NJZ004-103.
MARINE...SMALL CRAFT ADVISORY UNTIL 6 PM EDT THIS EVENING FOR ANZ330-
335-338-340-345-350-353-355.
GALE WARNING FROM 6 PM THIS EVENING TO 6 AM EDT WEDNESDAY FOR
ANZ330-335-338-340-345-355.
GALE WARNING FROM 6 PM THIS EVENING TO 6 PM EDT WEDNESDAY FOR
ANZ350-353.
&&
$$
SYNOPSIS...GOODMAN/MALOIT/SEARS
NEAR TERM...GOODMAN
SHORT TERM...MALOIT
LONG TERM...SEARS
AVIATION...JM
MARINE...MALOIT/SEARS
HYDROLOGY...GOODMAN
AREA FORECAST DISCUSSION
NWS NEW YORK NY
506 AM EDT TUE MAR 19 2013
.SYNOPSIS...
A COASTAL LOW WILL PASS JUST SOUTH OF LONG ISLAND TODAY...THEN
MOVE FROM THE GULF OF MAINE TONIGHT INTO THE CANADIAN MARITIMES ON
WEDNESDAY. ANOTHER COASTAL LOW WILL DEVELOP OFF THE MID ATLANTIC
COAST WEDNESDAY NIGHT...AND TRACK WELL SOUTHEAST OF LONG ISLAND
THURSDAY AND WELL EAST OF CAPE COD THURSDAY NIGHT. WEAK HIGH
PRESSURE WILL BUILD IN ON FRIDAY AND REMAIN THROUGH THE WEEKEND.
LOW PRESSURE WILL PASS TO THE SOUTH EARLY NEXT WEEK.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
LOW PRESSURE IS NOW OFF THE SRN NJ COAST...AND LOOKS TO PASS JUST
S OF LONG ISLAND TODAY PER GREATEST 3-HRLY PRESSURE FALLS
CENTERED NEAR 40N 71W ATTM. MID LEVEL WARMING IS IN PROCESS OF
CHANGING P-TYPE TO EITHER RAIN OR FREEZING RAIN...WITH JUST A
SLIVER OF LIGHT SNOWFALL HANGING ON ATTM IN ORANGE COUNTY WHICH
SHOULD ALSO CHANGE TO FREEZING RAIN SHORTLY. LOW LEVEL WARMING
ON E FLOW HAS CHANGED PRECIP TO RAIN ALONG THE COAST AND IN NYC
METRO...SO MOST ADVYS WILL BE DROPPED THERE EXCEPT FOR WRN
BERGEN/E PASSAIC...WHERE SOME FREEZING RAIN MAY OCCUR AS TEMPS
HOVER AROUND FREEZING FOR A WHILE.
AS FOR THE INTERIOR...MOS CONTINUES TO BE TOO QUICK TO WARM
THINGS UP AND USED 04Z RAP 2M TEMPS THROUGH THE MORNING...KEEPING
SFC TEMPS AOB FREEZING WHICH ALONG WITH WARMING ALOFT POINTS TO
SEVERAL HRS OF FREEZING RAIN INTO THE MORNING. MANY LOWER HUDSON
VALLEY LOCATIONS HAVE ALREADY HAD UP TO 6 INCHES OF SNOW...WHILE
MOST OF SRN CT HAS SEEN 3-4 INCHES OF SNOWFALL. THIS SNOWFALL PLUS
1/10 TO 1/4 INCH OF ICE INTO THE MORNING COMMUTE JUSTIFIES KEEPING
WINTER STORM WARNINGS UP ACROSS THE INTERIOR BASED ON IMPACT.
PRECIP HAS BECOME MORE SPOTTY IN NATURE ATTM ACROSS FAR NW
SECTIONS...BUT SHOULD FILL IN AGAIN DURING THE MORNING AND EARLY
AFTERNOON AS A POTENT MID LEVEL VORT MAX ROUNDS THE BASE OF A
CLOSED LOW CENTERED OVER THE UPPER GREAT LAKES AND MOVES ACROSS
THE LOCAL AREA. AFTER THIS VORT PASSES...PRECIP SHOULD END AND
SKIES MAY BRIGHTEN DURING THE MID TO LATE AFTERNOON ON A BRISK
DOWNSLOPE W FLOW ACROSS NYC METRO AND THE LOWER HUDSON VALLEY.
FOR HIGH TEMPS...BLENDED MAV/MET WITH COLDER 04Z RAP 2M
TEMPS...WITH HIGHS ONLY NEAR 40 INLAND WHICH COULD STILL BE A
LITTLE GENEROUS ESPECIALLY ACROSS SRN CT...AND MID 40S FOR NYC
METRO AND LONG ISLAND.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH FRIDAY/...
FAST W TO WSW FLOW ALOFT TONIGHT AND THURSDAY AS CLOSED LOW BUILDS
INTO NORTHERN NEW ENGLAND...THEN SE CANADA. SHOULD BE DRY TONIGHT
AND THURSDAY WITH LITTLE IF ANY IN THE WAY OF FORCING - HOWEVER IF
UPPER TROUGH AXIS IS A TAD SLOWER IN PUSHING THROUGH THAN CURRENTLY
FORECAST COULD SEE SOME -SHSN ACROSS NORTHERN ZONES EARLY THIS
EVENING. FOR LOWS TONIGHT USED A BLEND OF MAV/MET GUIDANCE WITH
VALUES FORECAST TO BE A FEW DEGREES ABOVE NORMAL. USED A BLEND OF
MAV/MET GUIDANCE WITH NAM 2-METER TEMPERATURES AND A MIX DOWN FROM
850 HPA NEAR THE IMMEDIATE COAST...800 HPA ACROSS FAR INTERIOR AREAS
AND 825 HPA IN BETWEEN. THIS YIELDS HIGHS AROUND 10 DEGREES BELOW
NORMAL.
A COASTAL LOW DEVELOPS OFF THE MID ATLANTIC COAST WEDNESDAY NIGHT IN
RESPONSE TO A SOUTHERN STREAM SHORTWAVE MOVING OFFSHORE - THIS LOW
THEN MOVES WELL SE OF LONG ISLAND THURSDAY AND TO THE E OF CAPE COD
THURSDAY NIGHT AS THE NORTHERN STREAM CUTOFF LOW PIVOTS TO THE SE
INTO THE TRI-STATE. THE RESULT WILL BE CHANCE POPS COASTAL
AREAS/SLIGHT CHANCE POPS ELSEWHERE FOR LIGHT SNOW FROM LATE
WEDNESDAY NIGHT INTO THURSDAY EVENING - EXCEPT OVER FAR NW ZONES
WHERE ONLY COULD SEE A FEW FLURRIES.
USED A BLEND OF MAV/MET GUIDANCE FOR LOWS WEDNESDAY NIGHT WITH
VALUES FORECAST TO BE AROUND 5 DEGREES BELOW NORMAL. USED A BLEND OF
MIXING DOWN FROM 850 HPA NEAR THE COAST...800 HPA WELL INLAND...AND
825 HPA IN BETWEEN...WITH A BLEND OF MAV/MET GUIDANCE...AND NAM AND
ECMWF 2-METER TEMPERATURES. THIS YIELDS VALUES 10-15 DEGREES BELOW
NORMAL. FOR LOWS THURSDAY NIGHT USED A BLEND OF MEX/MEX ENSEMBLE
MEAN/ECE/WPC GUIDANCE WITH VALUES AROUND 5 DEGREES BELOW NORMAL.
NW FLOW ALOFT FRIDAY WITH UPPER LOW OVER N AND E NEW ENGLAND - COULD
GET ENOUGH FORCING OUT OUT OF A PASSING SHORTWAVE IN THE AFTERNOON
TO WARRANT SLIGHT CHANCE POPS FOR -SHSN/-SHRA OVER FAR NW ZONES. FOR
HIGHS USED A BLEND OF MEX/MEX ENSEMBLE MEAN/ECE/WPC GUIDANCE WITH
VALUES AROUND 10 DEGREES BELOW NORMAL.
&&
.LONG TERM /FRIDAY NIGHT THROUGH MONDAY/...
MODELS BEGINNING TO COME INTO BETTER AGREEMENT WITH THE HANDLING
AND TIMING OF HIGH PRESSURE SYSTEM OVER THE COMING WEEKEND...AND
THE NEXT LOW PRESSURE SYSTEM FOR NEXT MONDAY/TUESDAY.
HIGH PRESSURE BUILDS TO THE SOUTH OVER THE NORTHEAST SATURDAY INTO
SUNDAY UNDER A BROAD UPPER LEVEL TROUGH. MULTIPLE SHORTWAVES
EXPECTED TO PASS THROUGH THE REGION WHILE ROTATING AROUND THE MAIN
UPPER LEVEL CLOSED LOW. DESPITE DECENT FORCING ASSOCIATED WITH EACH
PASSING WAVE...A PERSISTENT NORTHWESTERLY FLOW WILL KEEP A MAINLY
DRY VERTICAL COLUMN...RESULTING IN DRY CONDITIONS ACROSS THE AREA.
WHILE THE 12Z/18 RUNS HAD MUCH HIGHER DISCREPANCIES IN THE HANDLING
OF THE NEXT LOW...THE 00Z/19 RUNS ARE STARTING TO COME INTO BETTER
ALIGNMENT BUT STILL WITH SOME DIFFERENCES. LOW PRESSURE FORMS OVER
THE CENTRAL STATES ON SUNDAY...PROGRESSING TO THE EAST TO BEGIN
THE WEEK. 00Z ECMWF ACTUALLY THE MORE PROGRESSIVE OF THE SOLUTIONS...
WITH THE GFS LAGGING BEHIND WHILE DEVELOPING A SECONDARY LOW. THE
GFS THEN KEEPS THE UPPER LEVEL LOW FROM OVER THE WEEKEND NEARLY
STATIONARY...ALLOWING FOR POSSIBLE INTERACTION WITH THE NEXT LOW
TRAVERSING THE CENTRAL US...RESULTING IN MORE WIDESPREAD PCPN.
HOWEVER...THE PATTERN OF THE ECMWF KEEPS THE TRAVERSING LOW TO THE
SOUTH...BUILDING IN SUBSIDENCE OVER MOST OF THE
NORTHEAST...KEEPING THE HEAVIEST PCPN TO THE SOUTH. BECAUSE OF THE
MODEL SPREAD...CONTINUED THE SLIGHT CHC POPS FOR MONDAY INTO
TUESDAY.
GENERALLY USED A BLEND OF THE WPC AND MOS GUIDANCE FOR TEMPS THIS
WEEKEND INTO NEXT WEEK...WHICH KEEPS HIGH TEMPS SLIGHTLY BELOW
NORMAL AND OVERNIGHT LOWS RIGHT AROUND TO SLIGHTLY BELOW NORMAL.
&&
.AVIATION /09Z TUESDAY THROUGH SATURDAY/...
LOW PRESSURE WILL TRACK FROM THE DELMARVA TO JUST SOUTHEAST OF
NYC THIS MORNING. THE LOW PRESSURE MOVES INTO COASTAL NEW ENGLAND
THIS EVENING. INITIALLY EASTERLY GUSTS OF AROUND 20 KT WILL LOWER
AND WINDS OVERALL BECOME LIGHT AND VARIABLE THIS MORNING BEFORE
BECOMING MORE WESTERLY BY THE AFTERNOON...GUSTING 20-25 KT LATE.
THERE IS SOME UNCERTAINTY ON WHEN EXACTLY THE WINDS TURN MORE
WESTERLY AND THE TIMING COULD BE OFF BY 1-2 HOURS.
ICING MAINLY RESTRICTED TO KSWF WHERE SNOW WILL BE CHANGING TO
SLEET AND FREEZING RAIN THIS MORNING. ELSEWHERE...THE PRECIP TYPE
IS RAIN. ALL PRECIP BECOMES DRIZZLE LATER THIS MORNING...LINGERING
INTO THE AFTERNOON. MAINLY MVFR/IFR CONDITIONS WITH SOME POCKETS
OF LIFR WITH NO SUBSTANTIAL IMPROVEMENT EXPECTED UNTIL WINDS
BECOME MORE WESTERLY AND START GUSTING LATE IN THE AFTERNOON
GENERALLY AFTER 20Z. POSSIBLE VLIFR POSSIBLE IN FOG THIS MORNING
WHEN LOW IS WITHIN CLOSEST PROXIMITY OF THE TERMINALS. VFR RETURNS
BY THE EVENING WITH WEST WINDS GUSTING TO 25-30 KT.
...NY METRO ENHANCED AVIATION WEATHER SUPPORT...
DETAILED INFORMATION...INCLUDING HOURLY TAF WIND COMPONENT FCSTS
CAN BE FOUND AT: HTTP://WWW.ERH.NOAA.GOV/ZNY/N90 (LOWER CASE)
KJFK FCSTER COMMENTS: THE TIMING OF IFR VBSYS AND LIFR CIGS COULD
BE OFF BY 1-3 HOURS. WIND SHIFT TO NW COULD BE 1-2 HOURS OFF.
AMENDMENTS POSSIBLE.
KLGA FCSTER COMMENTS: THE TIMING OF IFR VBSYS AND LIFR CIGS COULD
BE OFF BY 1-3 HOURS. WIND SHIFT TO NW COULD BE 1-2 HOURS OFF.
AMENDMENTS POSSIBLE.
KEWR FCSTER COMMENTS: THE TIMING OF IFR VBSYS AND LIFR CIGS COULD
BE OFF BY 1-3 HOURS. WIND SHIFT TO NW COULD BE 1-2 HOURS OFF.
AMENDMENTS POSSIBLE.
THE AFTERNOON KEWR HAZE POTENTIAL FORECAST IS YELLOW...WHICH
IMPLIES SLANT RANGE VISIBILITY 4-6SM OUTSIDE OF CLOUD.
KTEB FCSTER COMMENTS: THE TIMING OF IFR VBSYS AND LOW END IFR
CIGS COULD BE OFF BY 1-3 HOURS. WIND SHIFT TO NW COULD BE 1-2
HOURS OFF. AMENDMENTS POSSIBLE.
KHPN FCSTER COMMENTS: THE TIMING OF LIFR CONDITIONS COULD BE OFF
BY 1-3 HOURS. WIND SHIFT TO NW COULD BE 1-2 HOURS OFF. AMENDMENTS
POSSIBLE.
KISP FCSTER COMMENTS: THE TIMING OF IFR VBSYS AND LIFR CIGS
COULD BE OFF BY 1-3 HOURS. WIND SHIFT TO NW COULD BE 1-2 HOURS
OFF. AMENDMENTS POSSIBLE.
.OUTLOOK FOR 09Z WED THROUGH SAT...
.WED...GENERALLY VFR. W WINDS WITH GUSTS INTO THE LOWER 20 KT
RANGE ON WED.
.THU...CHANCE OF SUB-VFR IN LIGHT RAIN OR SNOW.
.FRI...VFR. GUSTY NW WINDS POSSIBLE.
.SAT...VFR.
&&
.MARINE...
WILL MAINTAIN GALE WARNING THROUGH 6 AM OVER ALL WATERS - STILL
GUSTS TO GALE FORCE ONGOING BUT SHOULD TAPER OFF OVER THE NEXT 2-3
HOURS. MIGHT NEED TO EXTEND OVER FAR EASTERN OCEAN ZONE - BUT WILL
DECIDE CLOSER TO 6 AM.
FOR REMAINDER OF TODAY - WINDS SUBSIDE TO MAINLY SMALL CRAFT - WITH
SOME SUB-SMALL CRAFT CONDITIONS ON MORE PROTECTED WATERS. GALES THEN
RETURN FOR TONIGHT ON ALL WATERS WITH GALE GUSTS CONTINUING ON
WEDNESDAY OVER EASTERN COASTAL OCEAN WATERS WITH SMALL CRAFT
CONDITIONS ELSEWHERE.
THE PRESSURE GRADIENT CONTINUES TO RELAX OVER THE REGION WEDNESDAY
NIGHT...WITH ALL WATERS FALLING BELOW SCA LEVELS AFTER MIDNIGHT..AND
CONTINUE ON THURSDAY.
WIND GUSTS ON THE COASTAL OCEAN WATERS COULD REACH 25 KT THURSDAY
NIGHT IN THE WAKE OF THE DEPARTING...BUT STRENGTHENING COASTAL
LOW...WITH SUB-SMALL CRAFT CONDITIONS ON THE REMAINDER OF THE WATERS.
FRIDAY WILL FEATURE SUB-SMALL CRAFT CONDITIONS ON ALL WATERS AS THE
PRESSURE GRADIENT RELAXES...EXCEPT FOR POSSIBLY SWELLS BRING SCA
SEAS TO THE TWO EASTERN COASTAL WATER ZONES.
GENERALLY EXPECTING SUB-SCA CONDITIONS THIS WEEKEND WITH HIGH
PRESSURE BUILDING INTO THE REGION. A BRIEF PERIOD OF INTERACTION
BETWEEN THE DEPARTING LOW AND APPROACHING HIGH FRI NIGHT COULD
INCREASE WINDS ENOUGH FROM THE NORTHWEST...COMBINED WITH COLD AIR
ADVECTION TO PRODUCE 25 KT GUSTS AND 5 FT SEAS ON THE OCEAN.
CONDITIONS THEN WILL DIMINISH BY SATURDAY.
POSSIBLE SCA CONDITIONS AGAIN NEXT MONDAY AND TUESDAY WITH THE NEXT
LOW PRESSURE SYSTEM.
&&
.HYDROLOGY...
LIQUID EQUIVALENT STORM TOTAL QPF OF 1.00-1.25 INCHES EXPECTED.
PRECIP LIGHT ENOUGH ATTM THAT COMBINED LIGHT RAIN AND SNOW MELT
SHOULD NOT CAUSE MUCH IN THE WAY OF PROBLEMS.
DRY TONIGHT AND WEDNESDAY. THERE IS THE CHANCE FOR SOME LIGHT
PRECIPITATION FROM LATE WEDNESDAY NIGHT INTO THURSDAY EVENING
MAINLY OVER THE SE 1/2 OF THE TRI-STATE. NO HYDROLOGIC IMPACT
IS EXPECTED.
&&
.OKX WATCHES/WARNINGS/ADVISORIES...
CT...WINTER STORM WARNING UNTIL 10 AM EDT THIS MORNING FOR
CTZ005>008.
NY...WINTER STORM WARNING UNTIL 10 AM EDT THIS MORNING FOR
NYZ067>070.
NJ...WINTER STORM WARNING UNTIL 10 AM EDT THIS MORNING FOR NJZ002.
WINTER WEATHER ADVISORY UNTIL 10 AM EDT THIS MORNING FOR
NJZ004-103.
MARINE...GALE WARNING UNTIL 6 AM EDT EARLY THIS MORNING FOR ANZ330-335-
338-340-345-350-353-355.
&&
$$
SYNOPSIS...GOODMAN/MALOIT/SEARS
NEAR TERM...GOODMAN
SHORT TERM...MALOIT
LONG TERM...SEARS
AVIATION...JM
MARINE...MALOIT/SEARS
HYDROLOGY...GOODMAN
AREA FORECAST DISCUSSION
NWS NEW YORK NY
403 AM EDT TUE MAR 19 2013
.SYNOPSIS...
A COASTAL LOW WILL PASS JUST SOUTH OF LONG ISLAND TODAY...THEN
MOVE FROM THE GULF OF MAINE TONIGHT INTO THE CANADIAN MARITIMES ON
WEDNESDAY. ANOTHER COASTAL LOW WILL DEVELOP OFF THE MID ATLANTIC
COAST WEDNESDAY NIGHT...AND TRACK WELL SOUTHEAST OF LONG ISLAND
THURSDAY AND WELL EAST OF CAPE COD THURSDAY NIGHT. WEAK HIGH
PRESSURE WILL BUILD IN ON FRIDAY AND REMAIN THROUGH THE WEEKEND.
LOW PRESSURE WILL PASS TO THE SOUTH EARLY NEXT WEEK.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
LOW PRESSURE IS NOW OFF THE SRN NJ COAST...AND LOOKS TO PASS JUST
S OF LONG ISLAND TODAY PER GREATEST 3-HRLY PRESSURE FALLS
CENTERED NEAR 40N 71W ATTM. MID LEVEL WARMING IS IN PROCESS OF
CHANGING P-TYPE TO EITHER RAIN OR FREEZING RAIN...WITH JUST A
SLIVER OF LIGHT SNOWFALL HANGING ON ATTM IN ORANGE COUNTY WHICH
SHOULD ALSO CHANGE TO FREEZING RAIN SHORTLY. LOW LEVEL WARMING
ON E FLOW HAS CHANGED PRECIP TO RAIN ALONG THE COAST AND IN NYC
METRO...SO MOST ADVYS WILL BE DROPPED THERE EXCEPT FOR WRN
BERGEN/E PASSAIC...WHERE SOME FREEZING RAIN MAY OCCUR AS TEMPS
HOVER AROUND FREEZING FOR A WHILE.
AS FOR THE INTERIOR...MOS CONTINUES TO BE TOO QUICK TO WARM
THINGS UP AND USED 04Z RAP 2M TEMPS THROUGH THE MORNING...KEEPING
SFC TEMPS AOB FREEZING WHICH ALONG WITH WARMING ALOFT POINTS TO
SEVERAL HRS OF FREEZING RAIN INTO THE MORNING. MANY LOWER HUDSON
VALLEY LOCATIONS HAVE ALREADY HAD UP TO 6 INCHES OF SNOW...WHILE
MOST OF SRN CT HAS SEEN 3-4 INCHES OF SNOWFALL. THIS SNOWFALL PLUS
1/10 TO 1/4 INCH OF ICE INTO THE MORNING COMMUTE JUSTIFIES KEEPING
WINTER STORM WARNINGS UP ACROSS THE INTERIOR BASED ON IMPACT.
PRECIP HAS BECOME MORE SPOTTY IN NATURE ATTM ACROSS FAR NW
SECTIONS...BUT SHOULD FILL IN AGAIN DURING THE MORNING AND EARLY
AFTERNOON AS A POTENT MID LEVEL VORT MAX ROUNDS THE BASE OF A
CLOSED LOW CENTERED OVER THE UPPER GREAT LAKES AND MOVES ACROSS
THE LOCAL AREA. AFTER THIS VORT PASSES...PRECIP SHOULD END AND
SKIES MAY BRIGHTEN DURING THE MID TO LATE AFTERNOON ON A BRISK
DOWNSLOPE W FLOW ACROSS NYC METRO AND THE LOWER HUDSON VALLEY.
FOR HIGH TEMPS...BLENDED MAV/MET WITH COLDER 04Z RAP 2M
TEMPS...WITH HIGHS ONLY NEAR 40 INLAND WHICH COULD STILL BE A
LITTLE GENEROUS ESPECIALLY ACROSS SRN CT...AND MID 40S FOR NYC
METRO AND LONG ISLAND.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH FRIDAY/...
FAST W TO WSW FLOW ALOFT TONIGHT AND THURSDAY AS CLOSED LOW BUILDS
INTO NORTHERN NEW ENGLAND...THEN SE CANADA. SHOULD BE DRY TONIGHT
AND THURSDAY WITH LITTLE IF ANY IN THE WAY OF FORCING - HOWEVER IF
UPPER TROUGH AXIS IS A TAD SLOWER IN PUSHING THROUGH THAN CURRENTLY
FORECAST COULD SEE SOME -SHSN ACROSS NORTHERN ZONES EARLY THIS
EVENING. FOR LOWS TONIGHT USED A BLEND OF MAV/MET GUIDANCE WITH
VALUES FORECAST TO BE A FEW DEGREES ABOVE NORMAL. USED A BLEND OF
MAV/MET GUIDANCE WITH NAM 2-METER TEMPERATURES AND A MIX DOWN FROM
850 HPA NEAR THE IMMEDIATE COAST...800 HPA ACROSS FAR INTERIOR AREAS
AND 825 HPA IN BETWEEN. THIS YIELDS HIGHS AROUND 10 DEGREES BELOW
NORMAL.
A COASTAL LOW DEVELOPS OFF THE MID ATLANTIC COAST WEDNESDAY NIGHT IN
RESPONSE TO A SOUTHERN STREAM SHORTWAVE MOVING OFFSHORE - THIS LOW
THEN MOVES WELL SE OF LONG ISLAND THURSDAY AND TO THE E OF CAPE COD
THURSDAY NIGHT AS THE NORTHERN STREAM CUTOFF LOW PIVOTS TO THE SE
INTO THE TRI-STATE. THE RESULT WILL BE CHANCE POPS COASTAL
AREAS/SLIGHT CHANCE POPS ELSEWHERE FOR LIGHT SNOW FROM LATE
WEDNESDAY NIGHT INTO THURSDAY EVENING - EXCEPT OVER FAR NW ZONES
WHERE ONLY COULD SEE A FEW FLURRIES.
USED A BLEND OF MAV/MET GUIDANCE FOR LOWS WEDNESDAY NIGHT WITH
VALUES FORECAST TO BE AROUND 5 DEGREES BELOW NORMAL. USED A BLEND OF
MIXING DOWN FROM 850 HPA NEAR THE COAST...800 HPA WELL INLAND...AND
825 HPA IN BETWEEN...WITH A BLEND OF MAV/MET GUIDANCE...AND NAM AND
ECMWF 2-METER TEMPERATURES. THIS YIELDS VALUES 10-15 DEGREES BELOW
NORMAL. FOR LOWS THURSDAY NIGHT USED A BLEND OF MEX/MEX ENSEMBLE
MEAN/ECE/WPC GUIDANCE WITH VALUES AROUND 5 DEGREES BELOW NORMAL.
NW FLOW ALOFT FRIDAY WITH UPPER LOW OVER N AND E NEW ENGLAND - COULD
GET ENOUGH FORCING OUT OUT OF A PASSING SHORTWAVE IN THE AFTERNOON
TO WARRANT SLIGHT CHANCE POPS FOR -SHSN/-SHRA OVER FAR NW ZONES. FOR
HIGHS USED A BLEND OF MEX/MEX ENSEMBLE MEAN/ECE/WPC GUIDANCE WITH
VALUES AROUND 10 DEGREES BELOW NORMAL.
&&
.LONG TERM /FRIDAY NIGHT THROUGH MONDAY/...
MODELS BEGINNING TO COME INTO BETTER AGREEMENT WITH THE HANDLING
AND TIMING OF HIGH PRESSURE SYSTEM OVER THE COMING WEEKEND...AND
THE NEXT LOW PRESSURE SYSTEM FOR NEXT MONDAY/TUESDAY.
HIGH PRESSURE BUILDS TO THE SOUTH OVER THE NORTHEAST SATURDAY INTO
SUNDAY UNDER A BROAD UPPER LEVEL TROUGH. MULTIPLE SHORTWAVES
EXPECTED TO PASS THROUGH THE REGION WHILE ROTATING AROUND THE MAIN
UPPER LEVEL CLOSED LOW. DESPITE DECENT FORCING ASSOCIATED WITH EACH
PASSING WAVE...A PERSISTENT NORTHWESTERLY FLOW WILL KEEP A MAINLY
DRY VERTICAL COLUMN...RESULTING IN DRY CONDITIONS ACROSS THE AREA.
WHILE THE 12Z/18 RUNS HAD MUCH HIGHER DISCREPANCIES IN THE HANDLING
OF THE NEXT LOW...THE 00Z/19 RUNS ARE STARTING TO COME INTO BETTER
ALIGNMENT BUT STILL WITH SOME DIFFERENCES. LOW PRESSURE FORMS OVER
THE CENTRAL STATES ON SUNDAY...PROGRESSING TO THE EAST TO BEGIN
THE WEEK. 00Z ECMWF ACTUALLY THE MORE PROGRESSIVE OF THE SOLUTIONS...
WITH THE GFS LAGGING BEHIND WHILE DEVELOPING A SECONDARY LOW. THE
GFS THEN KEEPS THE UPPER LEVEL LOW FROM OVER THE WEEKEND NEARLY
STATIONARY...ALLOWING FOR POSSIBLE INTERACTION WITH THE NEXT LOW
TRAVERSING THE CENTRAL US...RESULTING IN MORE WIDESPREAD PCPN.
HOWEVER...THE PATTERN OF THE ECMWF KEEPS THE TRAVERSING LOW TO THE
SOUTH...BUILDING IN SUBSIDENCE OVER MOST OF THE
NORTHEAST...KEEPING THE HEAVIEST PCPN TO THE SOUTH. BECAUSE OF THE
MODEL SPREAD...CONTINUED THE SLIGHT CHC POPS FOR MONDAY INTO
TUESDAY.
GENERALLY USED A BLEND OF THE WPC AND MOS GUIDANCE FOR TEMPS THIS
WEEKEND INTO NEXT WEEK...WHICH KEEPS HIGH TEMPS SLIGHTLY BELOW
NORMAL AND OVERNIGHT LOWS RIGHT AROUND TO SLIGHTLY BELOW NORMAL.
&&
.AVIATION /08Z TUESDAY THROUGH SATURDAY/...
LOW PRESSURE WILL TRACK FROM THE DELMARVA TO JUST SOUTHEAST OF
NYC INTO THIS MORNING. THE LOW PRESSURE MOVES INTO COASTAL NEW
ENGLAND IN THE EVENING. INITIALLY EASTERLY GUSTS OF AROUND 20 KT
WILL LOWER AND WINDS OVERALL BECOME LIGHT AND VARIABLE EARLY IN
THE MORNING BEFORE BECOMING MORE WESTERLY BY THE
AFTERNOON...GUSTING 20-25 KT LATE. THERE IS SOME UNCERTAINTY ON
WHEN EXACTLY THE WINDS TURN MORE WESTERLY AND THE TIMING COULD BE
OFF BY 1-2 HOURS.
PRECIP TYPE NOW RAIN FOR CITY AND COASTAL TERMINALS WITH MAINLY
FREEZING RAIN AND SLEET FOR KHPN AND KSWF. KSWF WILL STILL HAVE
SOME MORE SNOW BEFORE TRANSITIONING TO FREEZING RAIN AND SLEET.
FOR KSWF...SNOWFALL RATES AT KSWF 1/2 TO 1 INCH PER HOUR. ICING
EXPECTED THIS MORNING FOR KSWF.
ALL PRECIP BECOMES DRIZZLE LATER IN THE MORNING...LINGERING INTO
THE AFTERNOON. MAINLY MVFR/IFR CONDITIONS WITH SOME POCKETS OF
LIFR WITH NO SUBSTANTIAL IMPROVEMENT EXPECTED UNTIL WINDS BECOME
MORE WESTERLY AND START GUSTING LATE IN THE AFTERNOON GENERALLY
AFTER 20Z. POSSIBLE VLIFR POSSIBLE IN FOG THIS MORNING WHEN LOW
IS WITHIN CLOSEST PROXIMITY OF THE TERMINALS. VFR RETURNS BY THE
EVENING.
.OUTLOOK FOR 06Z WED THROUGH SAT...
.LATE TUE NGT...VFR WITH W WINDS 20-30KT.
.WED...GENERALLY VFR. W WINDS WITH GUSTS INTO THE LOWER 20 KT
RANGE ON WED.
.THU...CHANCE OF SUB-VFR IN LIGHT RAIN OR SNOW.
.FRI...VFR. GUSTY NW WINDS POSSIBLE.
.SAT...VFR.
&&
.MARINE...
WILL MAINTAIN GALE WARNING THROUGH 6 AM OVER ALL WATERS - STILL
GUSTS TO GALE FORCE ONGOING BUT SHOULD TAPER OFF OVER THE NEXT 2-3
HOURS. MIGHT NEED TO EXTEND OVER FAR EASTERN OCEAN ZONE - BUT WILL
DECIDE CLOSER TO 6 AM.
FOR REMAINDER OF TODAY - WINDS SUBSIDE TO MAINLY SMALL CRAFT - WITH
SOME SUB-SMALL CRAFT CONDITIONS ON MORE PROTECTED WATERS. GALES THEN
RETURN FOR TONIGHT ON ALL WATERS WITH GALE GUSTS CONTINUING ON
WEDNESDAY OVER EASTERN COASTAL OCEAN WATERS WITH SMALL CRAFT
CONDITIONS ELSEWHERE.
THE PRESSURE GRADIENT CONTINUES TO RELAX OVER THE REGION WEDNESDAY
NIGHT...WITH ALL WATERS FALLING BELOW SCA LEVELS AFTER MIDNIGHT..AND
CONTINUE ON THURSDAY.
WIND GUSTS ON THE COASTAL OCEAN WATERS COULD REACH 25 KT THURSDAY
NIGHT IN THE WAKE OF THE DEPARTING...BUT STRENGTHENING COASTAL
LOW...WITH SUB-SMALL CRAFT CONDITIONS ON THE REMAINDER OF THE WATERS.
FRIDAY WILL FEATURE SUB-SMALL CRAFT CONDITIONS ON ALL WATERS AS THE
PRESSURE GRADIENT RELAXES...EXCEPT FOR POSSIBLY SWELLS BRING SCA
SEAS TO THE TWO EASTERN COASTAL WATER ZONES.
GENERALLY EXPECTING SUB-SCA CONDITIONS THIS WEEKEND WITH HIGH
PRESSURE BUILDING INTO THE REGION. A BRIEF PERIOD OF INTERACTION
BETWEEN THE DEPARTING LOW AND APPROACHING HIGH FRI NIGHT COULD
INCREASE WINDS ENOUGH FROM THE NORTHWEST...COMBINED WITH COLD AIR
ADVECTION TO PRODUCE 25 KT GUSTS AND 5 FT SEAS ON THE OCEAN.
CONDITIONS THEN WILL DIMINISH BY SATURDAY.
POSSIBLE SCA CONDITIONS AGAIN NEXT MONDAY AND TUESDAY WITH THE NEXT
LOW PRESSURE SYSTEM.
&&
.HYDROLOGY...
LIQUID EQUIVALENT STORM TOTAL QPF OF 1.00-1.25 INCHES EXPECTED.
PRECIP LIGHT ENOUGH ATTM THAT COMBINED LIGHT RAIN AND SNOW MELT
SHOULD NOT CAUSE MUCH IN THE WAY OF PROBLEMS.
DRY TONIGHT AND WEDNESDAY. THERE IS THE CHANCE FOR SOME LIGHT
PRECIPITATION FROM LATE WEDNESDAY NIGHT INTO THURSDAY EVENING
MAINLY OVER THE SE 1/2 OF THE TRI-STATE. NO HYDROLOGIC IMPACT
IS EXPECTED.
&&
.OKX WATCHES/WARNINGS/ADVISORIES...
CT...WINTER STORM WARNING UNTIL 10 AM EDT THIS MORNING FOR
CTZ005>008.
NY...WINTER STORM WARNING UNTIL 10 AM EDT THIS MORNING FOR
NYZ067>070.
NJ...WINTER STORM WARNING UNTIL 10 AM EDT THIS MORNING FOR NJZ002.
WINTER WEATHER ADVISORY UNTIL 10 AM EDT THIS MORNING FOR
NJZ004-103.
MARINE...GALE WARNING UNTIL 6 AM EDT EARLY THIS MORNING FOR ANZ330-335-
338-340-345-350-353-355.
&&
$$
SYNOPSIS...GOODMAN/MALOIT/SEARS
NEAR TERM...GOODMAN
SHORT TERM...MALOIT
LONG TERM...SEARS
AVIATION...JM
MARINE...MALOIT/SEARS
HYDROLOGY...GOODMAN
AREA FORECAST DISCUSSION
NWS MOUNT HOLLY NJ
1207 PM EDT TUE MAR 19 2013
.SYNOPSIS...
LOW PRESSURE EAST OF NEW JERSEY THIS MORNING WILL CONTINUE TO
DEEPEN WHILE MOVING TOWARD NEW ENGLAND BY TONIGHT. A RIDGE OF HIGH
PRESSURE WILL MOVE IN WEDNESDAY BEFORE A COLD FRONT CROSSES THE
AREA DURING THE AFTERNOON. AN AREA OF LOW PRESSURE WILL FORM ALONG
THE FRONT WEDNESDAY NIGHT AND MOVE OUT INTO THE ATLANTIC THURSDAY.
EXTENSIVE HIGH PRESSURE CENTERED IN NORTHERN CANADA WILL DOMINATE
MUCH OF NORTH AMERICA FRIDAY AND SATURDAY. LOW PRESSURE DEVELOPING
ALONG THE GULF COAST NEXT WEEKEND WILL NEED TO BE MONITORED FOR A
POSSIBLE TURN UP THE COAST EARLY NEXT WEEK.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
STILL EXPECTING WLY FLOW WILL INCREASE AND CLEARING WILL TAKE PLACE FM
WEST TO EAST AS AN UPPER IMPLS MOVES PAST THE AREA. GUSTY W WIND
THIS AFTN 25-30 MPH AND POSSIBLY THE MILDEST DAY OF THE WEEK AND
PROBABLY THE MILDEST SINCE THE 15TH. NEAR NORMAL TEMPS EXPECTED, THOUGH DID
LOWER TEMPS A FEW DEGREES BASED ON 16Z METAR OBS. STILL THINK
CLEARING LATER TODAY WILL ALLOW FOR WARMING DEWPOINTS ALSO RAISED A BIT
ACROSS THE SOUTH.
STG NEG TILT TROUGH ROLLING THRU PA AND NJ LATE TODAY AND PER SPC WRF
HAVE A CHANCE OF LATE AFTN/EVE SHOWERS FM W TO E ACROSS PA.
PROBABLY OCCURS IN SHORT N-S LINES.
OTRW THE FCST WAS BLENDED 00Z/19 NCEP MOS WITH A LEAN COLDER IN YDYS
SNOW ACCUM AREA N OF I78.
OUR PUBLIC INFO STATEMENT ON SNOWFALL WAS UPDATED AT 900 AM AND
THIS SHOULD BE THE FINAL STATEMENT FOR THIS EVENT.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 AM WEDNESDAY/...
TONIGHT...CLEAR TO PC WITH GUSTY WNW WINDS DIMINISHING A BIT.
THE FCST WAS BASED ON BLENDED 00Z/19 NCEP MOS GUIDANCE. A FEW
FLURRIES POSSIBLE IN THE POCONOS.
&&
.LONG TERM /WEDNESDAY THROUGH MONDAY/...
ONE MINOR SYSTEM AND THE POTENTIAL FOR A MORE SIGNIFICANT SYSTEM
AWAIT US IN THE LONG TERM PART OF THE FORECAST. THE UPPER TROUGH
ACROSS THE NORTHEAST AT THE BEGINNING OF THE PERIOD MOVES AWAY
THIS WEEKEND...BEFORE ANOTHER PROGRESSIVE H5 LOW FROM THE PLAINS
MOVES TOWARD THE REGION EARLY NEXT WEEK. TEMPERATURES WILL REMAIN
BELOW NORMAL THROUGH THE PERIOD WITH SOME MODERATION POSSIBLE
EARLY NEXT WEEK.
WEDNESDAY...THE UPPER LOW TO THE NORTH WILL BE SENDING AN UPPER
TROUGH ACROSS THE AREA WEDNESDAY ACCOMPANIED BY A MOSTLY DRY SFC
COLD FRONT. WE KEPT POPS BELOW SLGT CHC FOR NOW WITH A MOSTLY DRY
AIR MASS IN PLACE.
WED NIGHT INTO EARLY THU...WEAK LOW PRESSURE IS SHOWN DEVELOPING
ON THE COLD FRONT...WHICH WILL BE SOUTH OF THE AREA AT THIS
TIME...AND MOVING OFFSHORE LATE WED NIGHT. THERE IS THE CHC FOR
SOME SNOW LATE WED NIGHT INTO THU FOR DE/ERN NJ ASSOCIATED WITH
THIS LOW. WE KEPT THE POPS IN THE CHC RANGE FOR NOW AND PAINTED IN
SOME 0.5 - 1.0 INCH SNOW ACCUMS POSSIBLE. LOW CONFID IN THE TRACK
PRECIP FCST WITH THIS LOW.
THU INTO SUN... A MOSTLY DRY PERIOD IS EXPECTED WITH THE UPPER LOW
MOVING AWAY AND A SFC HIGH PRESSURE SYSTEM FROM CANADA EXTENDING
ITS INFLUENCE ACROSS THE AREA. SNOW SHOWERS ARE POSSIBLE ACROSS
THE SRN POCONOS...BUT ONLY SLGT CHCS ARE IN THE GRIDS ATTM.
SUN NIGHT INTO MONDAY...A PROGRESSIVE UPPER/SFC LOW IS SHOWN
MOVING ACROSS FROM THE SRN PLAINS INTO THE THE TENN VALLEY BY MON
MORNING. THE SYSTEM CONTINUES EASTWARD AND A SECOND LOW IS SHOWN
FORMING ALONG THE EAST COAST. THE 00Z EC MODEL BRINGS QPF ACROSS
THE SRN HALF OF THE FCST AREA MONDAY WITH THIS FEATURE. WE HAVE
CHC POPS IN THE GRIDS FOR NOW. THIS WILL BE THE SYSTEM TO WATCH
OVER THE NEXT SEVERAL DAYS.
&&
.AVIATION /16Z TUESDAY THROUGH SATURDAY/...
THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG, KILG,
KMIV, KACY AND SURROUNDING AREAS.
TODAY...IFR CONDS IN RAIN/DRIZZLE FOG WITH POSSIBLE LIFR CONDS IN
SPOTTY DENSE FOG THROUGH ABOUT 16 OR 17Z. THIS IS A LITTLE LATER
THAN PREVIOUS THINKING BUT IS SUPPORTED BY THE LATEST RAP MODEL
GUIDANCE.
WIND TURNS W DURING EARLY TO MID AFTERNOON AND INCREASES WITH
AFTN GUSTS TO 25 OR 30 KTS AND CONDS BECOMING VFR SCT-BKN AOA 3500
FT DURING MIDDAY. CHANCE OF BRIEF MVFR CONDS IN A LATE AFTN SHOWER
ASSOCIATED WITH A STRONG NEG TILT VORT MAX CROSSING PA AND NJ.
TONIGHT...VFR SCT CLDS AOA 5000 FT WITH CHANCE OF FLURRIES AND
BRIEF MVFR CONDS IN THE POCONOS. GUSTY WNW WIND TO 20 TO 25 KTS
DIMINISH LATE.
OUTLOOK...
WED...MOSTLY VFR EXPECTED WITH GUSTY WEST WINDS.
WED NIGHT INTO EARLY THU...VFR WEST. CLOUDS AND POSSIBLE MVFR IN
LIGHT SNOW ACROSS ERN NJ AND SRN/ERN DE.
THU THRU SAT...MOSTLY VFR. A FEW SNOW SHOWERS POSSIBLE ACROSS THE
SRN POCONOS.
&&
.MARINE...
FROM SANDY HOOK TO 44065...ISSUED SCA FOR THE DAY AND CONT GLW
THERE TONIGHT. OTRW SCA ON ALL THE REMAINING ATLC WATERS THROUGH
WED.
WE MAY NEED TO UPGRADE TO A GLW TONIGHT ALONG PORTIONS OF THE ATLC
WATERS....ESP VCNTY ENTRANCE TO DE BAY DOWN TO 44009 NEAR 06Z.
MIXED MODEL SIGNALS ON WHERE THE BEST TRANSFER WILL OCCUR. NOT
ENOUGH MODEL SUPPORT TO GO WIDESPREAD ON A GALE IN THIS EARLY
MORNING FCST PACKAGE.
THE GLW VERIFICATION IN ANZ450 WAS FROM SANDY HOOK TO 44065 FROM
ROUGHLY 22Z YDY THROUGH 08Z THIS MORNING WITH A PEAK GUST OF 41 KT
AT 44065 AND MULTIPLE 37 KT AT SHOOK...ON THE NRN FRINGE OF ANZ
450.
OUTLOOK...
SCA CONDITIONS WITH GUSTY WEST TO NORTHWEST WINDS WED INTO
THU...THEN SUB-SCA CONDITIONS INTO THE WEEKEND. POTENTIAL FOR A
MORE SIGNIFICANT MARINE STORM EARLY NEXT WEEK.
&&
.PHI WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NJ...NONE.
DE...NONE.
MD...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 6 PM EDT WEDNESDAY FOR ANZ451>455.
SMALL CRAFT ADVISORY UNTIL 6 PM EDT THIS EVENING FOR ANZ450.
GALE WARNING FROM 6 PM THIS EVENING TO 4 AM EDT WEDNESDAY FOR
ANZ450.
SMALL CRAFT ADVISORY UNTIL 6 AM EDT WEDNESDAY FOR ANZ430-431.
&&
$$
SYNOPSIS...O`HARA
NEAR TERM...AMC/GAINES
SHORT TERM...DRAG
LONG TERM...O`HARA
AVIATION...AMC/O`HARA
MARINE...DRAG/O`HARA
AREA FORECAST DISCUSSION
NWS MOUNT HOLLY NJ
946 AM EDT TUE MAR 19 2013
.SYNOPSIS...
LOW PRESSURE EAST OF NEW JERSEY THIS MORNING WILL CONTINUE TO
DEEPEN WHILE MOVING TOWARD NEW ENGLAND BY TONIGHT. A RIDGE OF HIGH
PRESSURE WILL MOVE IN WEDNESDAY BEFORE A COLD FRONT CROSSES THE
AREA DURING THE AFTERNOON. AN AREA OF LOW PRESSURE WILL FORM ALONG
THE FRONT WEDNESDAY NIGHT AND MOVE OUT INTO THE ATLANTIC THURSDAY.
EXTENSIVE HIGH PRESSURE CENTERED IN NORTHERN CANADA WILL DOMINATE
MUCH OF NORTH AMERICA FRIDAY AND SATURDAY. LOW PRESSURE DEVELOPING
ALONG THE GULF COAST NEXT WEEKEND WILL NEED TO BE MONITORED FOR A
POSSIBLE TURN UP THE COAST EARLY NEXT WEEK.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
THE WINTER STORM WARNING WAS CANCELLED EARLIER BUT REPLACED BY A
WINTE WEATHER ADVISORY UNTIL 1000 AM...AND THE REMAINING ADVISORY
WAS ALSO EXTENDED TO 1000 AM. TEMPERATURES ARE SLOWLY WARMING BUT
REMAIN BELOW FREEZING AT SOME HIGHER ELEVATIONS. WILL LET THE
ADVISORY EXPIRE ALTHO A FEW HIGHEST ELEVATIONS MIGHT STAY AT OR
BELOW FREEZING FOR ANOTHER HOUR OR TWO. WE HAVE ALSO RECEIVED A
REPORT OF RAIN CHANGING BACK TO SNOW OVER THE POCONOS AS COLDER
AIR MOVES IN ALOFT
OTRW SOME MORNING PATCHY FOG CONTINUES. AS ANTICIPATED...ANOTHER
BAND OF RAIN IS MOVING ACROSS EASTER PA AND MUCH OF NEW JERSEY.
PRECIP AMOUNTS FROM THIS BAND SHOULD BE JUST A FEW HUNDREDTHS OF
AN INCH.
DURING EARLY TO MID AFTERNOON WLY FLOW WILL INCREASE AND CLEARING
WILL TAKE PLACE FM WEST TO EAST AS AN UPPER IMPLS MOVES PAST THE
AREA. THIS IS A LITTLE BIT LATER THAN PREVIIOUS THINKING. GUSTY W
WIND THIS AFTN 25-30 MPH AND POSSIBLY THE MILDEST DAY OF THE WEEK
AND PROBABLY THE MILDEST SINCE THE 15TH. NEAR NORMAL TEMPS.
STG NEG TILT TROUGH ROLLING THRU PA AND NJ LATE TODAY AND PER SPC WRF
HAVE A CHANCE OF LATE AFTN/EVE SHOWERS FM W TO E ACROSS PA.
PROBABLY OCCURS IN SHORT N-S LINES.
OTRW THE FCST WAS BLENDED 00Z/19 NCEP MOS WITH A LEAN COLDER IN YDYS
SNOW ACCUM AREA N OF I78.
OUR PUBLIC INFO STATEMENT ON SNOWFALL WAS UPDATED AT 900 AM AND
THIS SHOULD BE THE FINAL STATEMENT FOR THIS EVENT.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 AM WEDNESDAY/...
TONIGHT...CLEAR TO PC WITH GUSTY WNW WINDS DIMINISHING A BIT.
THE FCST WAS BASED ON BLENDED 00Z/19 NCEP MOS GUIDANCE. A FEW
FLURRIES POSSIBLE IN THE POCONOS.
&&
.LONG TERM /WEDNESDAY THROUGH MONDAY/...
ONE MINOR SYSTEM AND THE POTENTIAL FOR A MORE SIGNIFICANT SYSTEM
AWAIT US IN THE LONG TERM PART OF THE FORECAST. THE UPPER TROUGH
ACROSS THE NORTHEAST AT THE BEGINNING OF THE PERIOD MOVES AWAY
THIS WEEKEND...BEFORE ANOTHER PROGRESSIVE H5 LOW FROM THE PLAINS
MOVES TOWARD THE REGION EARLY NEXT WEEK. TEMPERATURES WILL REMAIN
BELOW NORMAL THROUGH THE PERIOD WITH SOME MODERATION POSSIBLE
EARLY NEXT WEEK.
WEDNESDAY...THE UPPER LOW TO THE NORTH WILL BE SENDING AN UPPER
TROUGH ACROSS THE AREA WEDNESDAY ACCOMPANIED BY A MOSTLY DRY SFC
COLD FRONT. WE KEPT POPS BELOW SLGT CHC FOR NOW WITH A MOSTLY DRY
AIR MASS IN PLACE.
WED NIGHT INTO EARLY THU...WEAK LOW PRESSURE IS SHOWN DEVELOPING
ON THE COLD FRONT...WHICH WILL BE SOUTH OF THE AREA AT THIS
TIME...AND MOVING OFFSHORE LATE WED NIGHT. THERE IS THE CHC FOR
SOME SNOW LATE WED NIGHT INTO THU FOR DE/ERN NJ ASSOCIATED WITH
THIS LOW. WE KEPT THE POPS IN THE CHC RANGE FOR NOW AND PAINTED IN
SOME 0.5 - 1.0 INCH SNOW ACCUMS POSSIBLE. LOW CONFID IN THE TRACK
PRECIP FCST WITH THIS LOW.
THU INTO SUN... A MOSTLY DRY PERIOD IS EXPECTED WITH THE UPPER LOW
MOVING AWAY AND A SFC HIGH PRESSURE SYSTEM FROM CANADA EXTENDING
ITS INFLUENCE ACROSS THE AREA. SNOW SHOWERS ARE POSSIBLE ACROSS
THE SRN POCONOS...BUT ONLY SLGT CHCS ARE IN THE GRIDS ATTM.
SUN NIGHT INTO MONDAY...A PROGRESSIVE UPPER/SFC LOW IS SHOWN
MOVING ACROSS FROM THE SRN PLAINS INTO THE THE TENN VALLEY BY MON
MORNING. THE SYSTEM CONTINUES EASTWARD AND A SECOND LOW IS SHOWN
FORMING ALONG THE EAST COAST. THE 00Z EC MODEL BRINGS QPF ACROSS
THE SRN HALF OF THE FCST AREA MONDAY WITH THIS FEATURE. WE HAVE
CHC POPS IN THE GRIDS FOR NOW. THIS WILL BE THE SYSTEM TO WATCH
OVER THE NEXT SEVERAL DAYS.
&&
.AVIATION /14Z TUESDAY THROUGH SATURDAY/...
THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG, KILG,
KMIV, KACY AND SURROUNDING AREAS.
TODAY...IFR CONDS IN RAIN/DRIZZLE FOG WITH POSSIBLE LIFR CONDS IN
SPOTTY DENSE FOG THROUGH ABOUT 16 OR 17Z. THIS IS A LITTLE LATER
THAN PREVIOUS THINKING BUT IS SUPPORTED BY THE LATEST RAP MODEL
GUIDANCE.
WIND TURNS W DURING EARLY TO MID AFTERNOON AND INCREASES WITH
AFTN GUSTS TO 25 OR 30 KTS AND CONDS BECOMING VFR SCT-BKN AOA 3500
FT DURING MIDDAY. CHANCE OF BRIEF MVFR CONDS IN A LATE AFTN SHOWER
ASSOCIATED WITH A STRONG NEG TILT VORT MAX CROSSING PA AND NJ.
TONIGHT...VFR SCT CLDS AOA 5000 FT WITH CHANCE OF FLURRIES AND
BRIEF MVFR CONDS IN THE POCONOS. GUSTY WNW WIND TO 20 TO 25 KTS
DIMINISH LATE.
OUTLOOK...
WED...MOSTLY VFR EXPECTED WITH GUSTY WEST WINDS.
WED NIGHT INTO EARLY THU...VFR WEST. CLOUDS AND POSSIBLE MVFR IN
LIGHT SNOW ACROSS ERN NJ AND SRN/ERN DE.
THU THRU SAT...MOSTLY VFR. A FEW SNOW SHOWERS POSSIBLE ACROSS THE
SRN POCONOS.
&&
.MARINE...
FROM SANDY HOOK TO 44065...ISSUED SCA FOR THE DAY AND CONT GLW
THERE TONIGHT. OTRW SCA ON ALL THE REMAINING ATLC WATERS THROUGH
WED.
WE MAY NEED TO UPGRADE TO A GLW TONIGHT ALONG PORTIONS OF THE ATLC
WATERS....ESP VCNTY ENTRANCE TO DE BAY DOWN TO 44009 NEAR 06Z.
MIXED MODEL SIGNALS ON WHERE THE BEST TRANSFER WILL OCCUR. NOT
ENOUGH MODEL SUPPORT TO GO WIDESPREAD ON A GALE IN THIS EARLY
MORNING FCST PACKAGE.
THE GLW VERIFICATION IN ANZ450 WAS FROM SANDY HOOK TO 44065 FROM
ROUGHLY 22Z YDY THROUGH 08Z THIS MORNING WITH A PEAK GUST OF 41 KT
AT 44065 AND MULTIPLE 37 KT AT SHOOK...ON THE NRN FRINGE OF ANZ
450.
OUTLOOK...
SCA CONDITIONS WITH GUSTY WEST TO NORTHWEST WINDS WED INTO
THU...THEN SUB-SCA CONDITIONS INTO THE WEEKEND. POTENTIAL FOR A
MORE SIGNIFICANT MARINE STORM EARLY NEXT WEEK.
&&
.PHI WATCHES/WARNINGS/ADVISORIES...
PA...WINTER WEATHER ADVISORY UNTIL 10 AM EDT THIS MORNING FOR
PAZ054-055-060>062.
NJ...WINTER WEATHER ADVISORY UNTIL 10 AM EDT THIS MORNING FOR
NJZ001-007-008.
DE...NONE.
MD...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 6 PM EDT WEDNESDAY FOR ANZ451>455.
SMALL CRAFT ADVISORY UNTIL 6 PM EDT THIS EVENING FOR ANZ450.
GALE WARNING FROM 6 PM THIS EVENING TO 4 AM EDT WEDNESDAY FOR
ANZ450.
SMALL CRAFT ADVISORY FROM 1 PM THIS AFTERNOON TO 6 AM EDT
WEDNESDAY FOR ANZ430-431.
&&
$$
SYNOPSIS...O`HARA
NEAR TERM...AMC
SHORT TERM...DRAG
LONG TERM...O`HARA
AVIATION...AMC/O`HARA
MARINE...AMC/O`HARA
AREA FORECAST DISCUSSION
NWS CHARLESTON SC
935 AM EDT TUE MAR 19 2013
.SYNOPSIS...
A COLD FRONT WILL MOVE THROUGH THE AREA FROM THE NORTHWEST TODAY...
FOLLOWED BY HIGH PRESSURE THROUGH WEDNESDAY AND ANOTHER COLD
FRONTAL PASSAGE WEDNESDAY NIGHT. RAIN CHANCES WILL INCREASE LATE
IN THE WEEK AND OVER THE WEEKEND AS A COUPLE LOW PRESSURE SYSTEMS
MOVE OVER OR JUST SOUTH OF THE AREA.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
THE COLD FRONT WILL MEANDER CLOSER TO THE COAST TODAY. THERE ARE
SIGNS THAT THE FRONT WILL BECOME INTERMINGLED WITHIN A DEVELOPING
SEA BREEZE LATER THIS AFTERNOON. RAP INSTABILITY PROGS SUGGEST A
SMALL POCKET OF INSTABILITY FEATURING LIFTED INDICES AS LOW AS -3C
WOULD DEVELOP FROM ROUGHLY BEAUFORT SOUTH TO SAVANNAH...DARIEN
AND LUDOWICI SHORTLY AFTER NOON...BUT THINK BY THAT TIME MOST OF
THE DEEPEST MOISTURE WILL BE SCOURING OUT AS DOWNSLOPE MID-LEVEL
TRAJECTORIES TAKE HOLD. WILL GO WITH A RAIN-FREE FORECAST FOR
TODAY...BUT IT WILL BE INTERESTING TO SEE IF A TSTM OR TWO COULD
POP IN THE SAID INSTABILITY CORRIDOR. OTHERWISE...LOWERED HIGH
TEMPERATURES JUST A BIT PER CURRENT SHORT TERM GUIDANCE. EXPECT
SKIES WILL CLEAR RAPIDLY FROM WEST-EAST THROUGH THE AFTERNOON.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH FRIDAY/...
COLD ADVECTION WILL PUSH OVERNIGHT TEMPERATURES INTO THE 40S AT
MOST LOCATIONS TONIGHT. ALONG THE IMMEDIATE COAST...NE WINDS WILL
HOLD TEMPS IN THE 50S. SKIES ARE EXPECTED TO START MOSTLY
CLEAR...THEN MODEL SOUNDINGS DEPICT INCREASING HIGH CLOUDS AS THE
NIGHT PROGRESSES.
DECENT CONFIDENCE THIS PERIOD. SURFACE HIGH PRESSURE WILL BE RIDGING
EASTWARD ACROSS THE CAROLINAS TO START THE DAY BUT A BACKDOOR COLD
FRONT WILL BE APPROACHING FROM THE NORTHWEST LATE IN THE DAY.
ALSO...LOW PRESSURE IS EXPECTED TO DEVELOP SOUTH AND SOUTHEAST OF
THE AREA. THE LOW COULD BE CLOSE ENOUGH AND MOISTURE DEEP ENOUGH TO
SQUEEZE OUT A FEW LIGHT SHOWERS...MAINLY ALONG THE COASTAL AREAS.
OTHERWISE IT WILL BE A COOL DAY WITH BELOW NORMAL TEMPERATURES IN
THE 60S...POSSIBLY COOLER DEPENDING ON THE CLOUD/RAIN COVERAGE.
COLDER HIGH PRESSURE WILL THEN MOVE IN WEDNESDAY NIGHT BEHIND A
REINFORCING COLD FRONT. TEMPERATURES COULD GET DOWN TO FREEZING WELL
INLAND TOWARD DAYBREAK THURSDAY AND A FREEZE WATCH MAY NEED TO BE
CONSIDERED. THE UPPER TROUGH AXIS LOOKS TO SHIFT OFFSHORE THURSDAY
WITH A COOL AIRMASS LINGERING OVER THE AREA. IT WILL BE DRY AND A
BIT BREEZY WITH TEMPERATURES POSSIBLY NOT GETTING OUT OF THE
50S...ESPECIALLY ACROSS SOUTHERN SOUTH CAROLINA. SURFACE HIGH
PRESSURE WILL SHIFT OVER THE AREA THURSDAY NIGHT AS MOISTURE BEGINS
TO INCREASE FROM THE WEST IN ASSOCIATION WITH LOW PRESSURE OVER
TEXAS. THERE COULD BE A FEW SHOWERS LATE...MAINLY WELL INLAND.
AGAIN...THERE COULD BE SOME FREEZING TEMPERATURES WELL INLAND ALONG
WITH SOME FROST BUT MUCH DEPENDS ON HOW QUICKLY THE CLOUD COVER
INCREASES AND THE RESULTANT EFFECT ON RADIATIONAL COOLING. ANOTHER
CHILLY DAY EXPECTED ON FRIDAY WITH INCREASED CLOUD COVER AND SOME
SHOWERS. TEMPERATURES COULD STRUGGLE TO GET OUT OF THE 50S AGAIN.
&&
.LONG TERM /FRIDAY NIGHT THROUGH MONDAY/...
CONFIDENCE REMAINS LOW IN THE EXACT DETAILS THIS PERIOD AS THERE ARE
STILL MODEL DISCREPANCIES REGARDING THE LATE WEEK/WEEKEND
PERIOD...PARTICULARLY WITH THE TRACK AND TIMING OF SEVERAL WAVES OF
LOW PRESSURE WHICH WILL BE RIDING ALONG A WARM FRONT LIKELY DRAPED
ACROSS SOUTHEAST GEORGIA. EXPECT HIGH RAIN CHANCES AND BELOW NORMAL
TEMPERATURES THROUGH SUNDAY WITH LOWER RAIN CHANCES AND SOME WARMER
TEMPERATURES LIKELY ON MONDAY. RAINFALL TOTALS THROUGH THE PERIOD
COULD REACH ONE OR TWO INCHES...POSSIBLY A BIT MORE...ESPECIALLY
ACROSS SOUTHEAST GEORGIA.
TEMPERATURES WILL BE RATHER TRICKY BUT LOOK TO REMAIN BELOW NORMAL
THROUGH THE PERIOD. IT IS CERTAINLY POSSIBLE THAT SOME
AREAS...ESPECIALLY INTERIOR PORTIONS OF SOUTHEAST SC/GA...DO NOT GET
OUT OF THE 50S THROUGH SUNDAY WITH THE WEDGE PATTERN IN PLACE.
&&
.AVIATION /14Z TUESDAY THROUGH SATURDAY/...
OCCASIONAL IFR/LIFT CONDITIONS WILL TRANSITION TO OCCASIONAL MVFR
CEILINGS 14-17Z...THEN VFR CONDITIONS WILL PREVAIL THROUGH TONIGHT
AS MUCH DRIER AIR SPREADS ACROSS THE REGION.
EXTENDED AVIATION OUTLOOK...MOSTLY VFR THROUGH FRIDAY WITH INCREASE
CHANCES OF SUB-VFR CONDITIONS THROUGH THE WEEKEND AS SEVERAL LOW
PRESSURE SYSTEMS ARE EXPECTED TO MOVE OVER OR JUST SOUTH OF KSAV.
BREEZY/GUSTY CONDITIONS EXPECTED THURSDAY.
&&
.MARINE...
TODAY...THE COLD FRONT LOOKS TO GET INTERMINGLED WITH THE SEA
BREEZE LATER TODAY...SO EXPECT A PERIOD OF VARIABLE WINDS TO
DEVELOP OVER MOST LEGS THIS AFTERNOON. BOTH WINDS AND SEAS WILL
REMAIN BELOW SMALL CRAFT ADVISORY THRESHOLDS.
OVERNIGHT...NE WINDS WILL SURGE TO 15-20 KT AND SEAS WILL BUILD
TO 3-5 FT. NO SMALL CRAFT ADVISORIES VALID AS OF THE EARLY TUESDAY
MORNING FORECAST PACKAGE.
WEAK HIGH PRESSURE WILL REMAIN ACROSS THE AREA WEDNESDAY WHILE A LOW
PRESSURE SYSTEM TRACKS WELL SOUTH AND EAST OF THE WATERS. A COLD
FRONT WILL THEN MOVE THROUGH WEDNESDAY NIGHT. HIGH PRESSURE WILL
THEN BUILD BACK IN THURSDAY INTO FRIDAY WITH SEVERAL AREAS OF LOW
PRESSURE TO TRACK OVER OR JUST SOUTH OF THE WATERS THROUGH THE
WEEKEND.
THIS PATTERN WILL YIELD SEVERAL BOUTS OF INCREASED WINDS AND SEAS
BUT OVERALL THE CHANCES OF ADVISORY CONDITIONS APPEAR LOW AT THIS
TIME...AT LEAST THROUGH FRIDAY. THE BEST CHANCE OF SCA CONDITIONS
WILL BE IN CHARLESTON HARBOR AND ACROSS THE WATERS BEYOND 20 NM
WED...POSSIBLY LINGERING INTO THU MORNING BEYOND 20 NM. THERE WILL
BE A CHANCE OF SCA CONDITIONS OVER THE WATERS THIS
WEEKEND...ESPECIALLY BEYOND 20 NM....BUT MUCH DEPENDS ON THE TRACK
OF THE AFOREMENTIONED LOW PRESSURE SYSTEMS.
&&
.CHS WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
SC...NONE.
MARINE...NONE.
&&
$$
ST
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
1234 AM CDT TUE MAR 19 2013
.DISCUSSION...
1037 PM CDT
UPDATE FOR OVERNIGHT...
STRONG COLD AIR ADVECTION THAT STARTED THIS AFTERNOON AND
CONTINUED THROUGH THE EVENING WILL PERSIST OVERNIGHT.
BLUSTERY CONDITIONS WILL ALSO CONTINUE AS UNIDIRECTIONAL W WIND
IS MAINTAINED WITH SPEEDS OF 35 TO 40 KT UP TO BASE OF INVERSION
AT 3-4K FT.
STRONG MID LEVEL TROUGH HAS ROTATED N TO THE NORTHERN GREAT LAKES
THIS EVENING TAKING THE SIGNIFICANT SNOW AND SNOW SHOWERS WITH
IT. A SECOND BROADER MID LEVEL TROUGH IS CURRENTLY ROTATING E
OVER WI AND IL WITH A SOME FLURRIES AND A FEW SNOW SHOWERS. IN
THE WAKE OF THIS TROUGH SKIES HAVE BECOME PARTLY CLOUDY/MOSTLY
CLEAR ACROSS THE NW 1/3RD OF THE LOCAL FORECAST AREA AS
SUBSIDENCE IN THE LOWER LEVELS INCREASES. EXPECT THIS TREND TO
CONTINUE OVERNIGHT AS THE MID LEVEL TROUGH ROTATES NE PAST THE
AREA THOUGH WHEN THIS COLD JUST ABOUT ANY PATCH OF STRATOCU CAN
PRODUCE SOME FLURRIES.
AREAS OF MAINLY LIGHT SNOW ARE OVER PORTIONS OF MN AND WI UNDER
THE UPPER TROUGH THAT IS CLOSING OFF TO AN UPPER LOW. WITH THIS
UPPER LOW TO MOVE SLOWLY E OVERNIGHT THE ASSOCIATED CLOUDS AND
SNOW SHOWERS/FLURRIES ARE EXPECTED TO BE N OF THE WI STATE LINE.
TRS
//PREV DISCUSSION...
345 PM CDT
WHILE THE TRUE VERNAL EQUINOX ARRIVES WEDNESDAY...AND WE ARE THREE
WEEKS INTO METEOROLOGICAL WINTER...THE MAIN WEATHER HEADLINE THIS
WEEK WILL BE HOW UNSPRING-LIKE THE TEMPERATURES WILL BE. THIS
PRESENTS THE MAIN FORECAST CHALLENGE...ALONG WITH ANY SMALL
CHANCES FOR SNOW SHOWERS.
SYNOPSIS AND LATE THIS AFTERNOON...THE POTENT UPPER LEVEL LOW IS
MOVING EAST ACROSS MN THIS AFTERNOON...WITH THE MID-LEVEL JET AND
A VORT LOBE OF THE SYSTEM RUSHING EASTWARD OVER NORTHERN IL.
ENHANCEMENT ON THE LEADING EDGE OF THESE STEEPER MID-LEVEL LAPSE
RATES AND CONVERGENCE IS SEEN IN SNOW SHOWERS TRAVERSING NORTHEAST
ILLINOIS AS OF 3 PM. SPOTTIER HEAVIER SNOWFALL RATES WILL BE SEEN
IN THIS ACTIVITY AS IT DEPARTS. THE SURFACE ARCTIC FRONT OF THIS
SYSTEM IS CROSSING THE MISSISSIPPI RIVER AND WILL MOVE THROUGH THE
ENTIRE CWA BETWEEN 5 AND 9 PM. THIS WILL TURN THE SYNOPTIC PATTERN
TO ONE OF NORTHWEST FLOW AND COLD WHICH WILL CONTINUE TO REINFORCE
ITSELF THROUGH THE WEEK AS THE UPPER AND SURFACE LOWS EXPAND AND
SLOW ACROSS THE CENTRAL AND EASTERN GREAT LAKES. NUMEROUS SHORT
WAVE IMPULSES ARE EXPECTED TO RIDE AROUND THIS FEATURE WITH
MINIMAL CAUSES FOR SNOW...BUT EACH DRIVING COLD SURGES BACK INTO
THE AREA.
TONIGHT...SHORT TERM GUIDANCE IS IN GOOD AGREEMENT ON THE TIMING
OF THE ARCTIC FRONT THIS EVENING...ALONG WITH AGREEING THAT THE
STEEPENING OF THE LOW-LEVEL LAPSE RATES WILL LIKELY PRODUCE
SURFACE-BASED INSTABILITY. FORECAST SOUNDINGS FROM THE RAP YIELD
AROUND 50 J/KG OF MLCAPE ALONG AND IMMEDIATELY BEHIND THE FRONT.
THE SATURATED DEPTH AT THE TOP OF THIS MIXED LAYER IS QUITE
SHALLOW BUT MOST CONVECTIVE-ALLOWING ARW AND WRF GUIDANCE DO
CONTINUE TO PRODUCE A SPATTERING OF HIGHER REFLECTIVITY INDICATIVE
OF SNOW SHOWERS. WILL CARRY FLURRIES WITH A MENTION OF ISOLATED TO
SCATTERED SNOW SHOWERS.
THE FRONT WILL BRING BOTH STRONG HEIGHT AND PRESSURE RISES WHICH
ARE LINED UP WELL WITH A UNIDIRECTIONAL WIND COLUMN IN THE LOW-
LEVELS. THE TOP OF THE MIXED LAYER ON THE LATEST RAP GUIDANCE AS
WELL AS LOCAL ARW DOES YIELD 40 MPH GUSTS THIS EVENING. HAVE
INCLUDED SUCH GUSTS IMMEDIATELY BEHIND THE FRONT AND WOULD NOT BE
SURPRISED IF SOME PLACES IN THE SOUTHWEST FORECAST AREA COME IN A
BIT HIGHER. IF SNOW SHOWERS DO DEVELOP...SOME NOTABLE REDUCTIONS
IN VISIBILITY MAY BE SEEN DUE TO THE COMBINATION OF WINDS AND
SNOWFALL. WITH TEMPERATURES FALLING QUICKLY...WIND CHILLS IN THE
NORTHWEST FORECAST AREA LOOK TO ALREADY BE IN THE SINGLE DIGITS
BY 9 PM THIS EVENING. THIS DEGREE OF COLD AIR WILL SWEEP OVER THE
ENTIRE FORECAST AREA WITH EARLY MORNING TEMPERATURES IN THE MID
TEENS TOWARD ROCKFORD TO AROUND 20 EAST. THESE ARE ABOUT 10 TO 15
DEGREES BELOW NORMAL.
TUESDAY AND TUESDAY NIGHT...UPPER LEVEL HEIGHTS WILL NOT RISE ANY
ON TUE WITH CYCLONIC FLOW IN COMPLETE CONTROL. HOWEVER...MOST
SHORT WAVE ENERGY IS LIKELY TO REMAIN TO THE NORTH AND EAST...SO
IT IS POSSIBLE TO SEE A LITTLE SCATTERING IN SOUTHERN AREAS. WITH
THE FIRST COLD POCKET OF AIR SHIFTING SLIGHTLY EAST OF THE
AREA...TEMPERATURES SHOULD MAKE IT BACK CLOSE TO TODAYS HIGHS.
WIND CHILLS WILL REMAIN IN THE MID TEENS TO MID 20S HOWEVER. A
SECOND COLD FRONT PUSHES THROUGH TOMORROW NIGHT ASSOCIATED WITH A
SHORT WAVE ROTATING AROUND THE PARENT LOW. THIS APPEARS STARVED
FOR DEEP MOISTURE BUT THE COLD AIR WILL BRING LOW TEMPERATURES
EVEN COOLER TUE NIGHT AND WIND CHILLS BELOW ZERO FOR WED MORNING.
WEDNESDAY AND THURSDAY...DUE TO SUCCESSIVE COLD FRONTS AND LIKELY
BROKEN TO OVERCAST STRATOCU GIVEN FORECAST SOUNDINGS FOR
WED...THIS SHOULD BE THE DAY WITH THE COLDEST HIGH TEMPERATURE. IN
FACT...THE HIGH TEMPERATURE FORECAST /22/ REMAINS A TIED RECORD
LOW MAXIMUM FOR ROCKFORD ON MARCH 20TH. BACKWARD PARCEL
TRAJECTORIES FROM THE GFS IN THIS TIME INDICATE THE AIR MASS
SOURCE REGION TO BE THE NORTHERN PROVINCES OF CANADA...NOT A
TYPICAL SOURCE REGION FOR LATE MARCH FOR THIS AREA. DEPENDING ON
CLOUD COVER WED NIGHT AND THE AMOUNT WINDS EASE...LOWS MAY ALSO
APPROACH RECORD LEVELS AS THE NEXT COLD POCKET OF AIR MOVES OVER
THE AREA /850MB TEMPS OF -15C TO -17C/. THIS NEXT COLD SURGE
ACTUALLY REORIENTS THE LOW-LEVEL WINDS TO MORE NORTHERLY AND THUS
LOOKS TO PRESENT AT LEAST THE POTENTIAL FOR LAKE EFFECT SNOW TO
SHIFT TOWARD NORTHWEST INDIANA WED NIGHT INTO THU. HAVE UPPED
CHANCES THERE AND CERTAINLY ACCUMULATING SNOW OF A FEW INCHES OR
MORE COULD BE REALIZED IF A FOCUSED AREA DEVELOPS...WHICH SUCH
DETAILS BEING DIFFICULT TO DETERMINE AT THIS FORECAST DISTANCE.
THURSDAY WILL BEGIN TO SEE MARGINAL MODIFICATION IN TEMPERATURES.
BEYOND...WITH THE ACTIVE SHORT TERM NOT OVERLY MUCH TIME SPENT ON
THIS FORECAST PERIOD. THE PATTERN LOOKS TO REMAIN BLOCKED OVER THE
WEEKEND...WITH CONFIDENCE INCREASING SOMEWHAT THAT THE MAIN STORM
TRACK WILL BE TO THE SOUTH OF THE AREA AND GENERAL HIGH PRESSURE
IN THE REGION. HIGH TEMPERATURES LOOK TO BE 5 TO 10 DEGREES BELOW
NORMAL.
MTF
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 06Z...
* VERY GUSTY WEST WINDS AROUND 30 KTS.
* HIGH END MVFR CEILINGS POSSIBLE THIS MORNING.
RODRIGUEZ
//DISCUSSION...UPDATED 06Z...
COLDER AIR CONTINUES TO PUSH SOUTHEAST ACROSS THE AREA EARLY THIS
MORNING AS A COLD FRONT EXITS TO THE SOUTHEAST. WITHIN THIS COLD
AIR...LOW LEVEL STRATUS AND STRONG WESTERLY WINDS PERSIST.
ALTHOUGH THERE MAY BE A BRIEF WINDOW IN THE NEAR TERM WHEN THE
CEILINGS SCATTER...UPSTREAM TRENDS SHOW THIS GAP FILLING BACK IN.
SO HAVE MAINTAINED BROKEN SKIES TO START TO THE FORECAST PERIOD
AND KEEP THEM THROUGH MID DAY...WITH ONLY SCATTER CLOUDS EXPECTED
THROUGH THE REMAINDER OF THE FORECAST PERIOD. IT DOES APPEAR THAT
CEILINGS MAY BE A TAD LOWER THAN PREVIOUSLY THOUGHT...AND SO HAVE
INTRODUCED HIGH END MVFR CEILINGS RANGING FROM 2500-2800 FT.
ALSO...ANY SNOW SHOWERS SHOULD BECOME MORE ISOLATED WITH TIME HERE
THIS MORNING. EXPECT WESTERLY WINDS TO PERSIST THROUGH THE
FORECAST PERIOD...GUSTING TO AROUND 30KT AT TIMES.
RODRIGUEZ
//ORD AND MDW CONFIDENCE...UPDATED 06Z...
* HIGH CONFIDENCE WITH WIND SPEED/DIRECTION.
* MEDIUM HIGH CONFIDENCE WITH CEILING TRENDS.
RODRIGUEZ
//OUTLOOK FOR ORD/MDW FOR 12Z WEDNESDAY-12Z MONDAY...UPDATED 00Z...
WEDNESDAY THROUGH SUNDAY...MVFR CIGS PSBL WED WITH GUSTY WEST WINDS.
OTHERWISE MAINLY VFR.
RATZER
&&
.MARINE...
222 PM CDT
LOW PRESSURE SPINNING SLOWLY THROUGH THE NORTHERN GREAT LAKES
TONIGHT THROUGH MIDWEEK WILL PUSH AN UNNECESSARILY COLD COLD FRONT
ACROSS LAKE MICHIGAN THIS EVENING. WINDS WILL TURN SOUTHWEST AND
THEN WEST BEHIND THE FRONT AND INCREASE STEADILY THROUGH THE
EVENING.
HAVE ELECTED TO CONTINUE THE GALE WARNING FOR THE SOUTHERN
TWO THIRDS OF THE LAKE AND ALSO TO MOVE UP THE START TIME FOR THE
MIDDLE THIRD SO THAT IT MATCHES THE ORIGINAL START TIME FOR THE
SOUTHERN THIRD. STILL THINK THE NORTHERN THIRD WILL BE CLOSE ENOUGH
TO THE LOW ITSELF TO SEE WEAKER WINDS AND GUSTS...THOUGH LOCAL AREAS
COULD RECEIVE PERIODIC GALE FORCE GUSTS. UNUSUAL FOR MARCH...THERE
IS ALSO A POSSIBILITY OF FREEZING SPRAY WITH THE COLD AND GUSTY
WINDS BEHIND THE FRONT TONIGHT AND TOMORROW.
WINDS WILL TURN NORTHWEST BY WEDNESDAY AND DIMINISH SOMEWHAT...BUT
COLD AIR WILL REMAIN IN PLACE THROUGH THE WEEK.
LENNING
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...GALE WARNING...LMZ080-LMZ366-LMZ565-LMZ567-LMZ669-LMZ671-LMZ673-
LMZ675-LMZ740-LMZ741-LMZ742-LMZ743-LMZ744-LMZ745-LMZ777-
LMZ779-LMZ868-LMZ870-LMZ872-LMZ874-LMZ876-LMZ878 UNTIL 9 PM
TUESDAY.
&&
$$
AREA FORECAST DISCUSSION
NWS GOODLAND KS
523 PM MDT WED MAR 20 2013
.SHORT TERM...(THIS EVENING THROUGH THURSDAY)
ISSUED AT 224 PM MDT WED MAR 20 2013
19Z WATER VAPOR IMAGERY RUC ANALYSIS INDICATED SHORT WAVE RIDGE
ACROSS NORTHERN PLAINS WITH STRONG TROUGH OVER THE PAC NW. AT THE
SFC...TROUGH WAS DEEPENING OVER EASTERN COLORADO WITH STRONG
SOUTH WINDS DEVELOPING ACROSS MUCH OF THE AREA. THICK CIRRUS HAS
SLOWED WARMING DOWN CONSIDERABLY BUT THINK TEMPS WILL EVENTUALLY
CLIMB INTO LOWER/MID 50S AS WINDS AID IN DEEP LAYER MIXING.
TONIGHT...WEAK SHORT WAVE TROUGH WILL UNDERCUT H5 RIDGE TONIGHT AS
STRONG WAA DEVELOPS TO THE NORTH OF DEVELOPING WARM FRONT ACROSS
NORTHERN CWA. HAVE SOME CONCERNS THAT LIGHT PRECIP MAY CLIP THE
NORTHEASTERN CWA IN AREA OF DEEP WAA...BUT VERTICAL PROFILES APPEAR
TO STABLE TO PRODUCE PRECIPITATION RATES NEEDED TO SATURATE SUB
CLOUD LAYER. PROBABILISTIC DATA SEEMS TO SUPPORT ANY PRECIP THREAT
REMAINING NORTH OF AREA AS WELL SO PLAN ON CONTINUING DRY FORECAST.
WILL HAVE TO WATCH UPSTREAM PRECIP POTENTIAL CLOSELY THOUGH AS WARM
LAYER AOB 3C THROUGH MUCH OF THE NIGHT WHICH WOULD REMOVE ANY ICE
FROM SOUNDING INITIALLY ALLOWING FOR RA/FZRA/IP TO FORM IF PRECIP
WERE TO OCCUR. AS MENTIONED BEFORE THIS REMAINS A VERY LOW
PROBABILITY AT THIS TIME AND IF PRECIP WERE TO OCCUR WET BULB
PROCESSES WOULD COOL WARM LAYER QUICKLY RESULTING IN A FAIRLY SHORT
DURATION.
TOMORROW...A FEW AREAS OF MORNING FOG EXPECTED AS WINDS SHIFT TO THE
EAST IN RESPONSE TO NEXT...MORE SIGNIFICANT SHORT WAVE TROUGH MOVING
INTO THE NORTHERN ROCKIES. THINK WEATHER ACROSS CWA WILL BE FAIRLY
QUIET THROUGH MUCH OF THE DAY...ALTHOUGH PRECIP THREAT WILL BEGIN TO
INCREASE IN THE AFTERNOON AS LARGE SCALE FORCING FOR ASCENT
INCREASES AND CAA ALOFT HELPS DESTABILIZE THINGS. DO NOT THINK
STABILITY PROFILES SUPPORT A THUNDER THREAT ATTM AND PLAN ON KEEPING
PRECIP TYPE AS RAIN THROUGH THE DAY.
.LONG TERM...(THURSDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 224 PM MDT WED MAR 20 2013
FIRST 500 MB SHORT WAVE WILL MOVE ACROSS THE HIGH PLAINS THURSDAY
NIGHT...THOUGH BEST ENERGY IS PROGGED TO BE NORTH OF THE FORECAST
AREA. INVERTED SURFACE TROUGH WILL PROVIDE LOW LEVEL CONVERGENCE
FROM GOODLAND TO MCCOOK. HOWEVER...MODEL SOUNDINGS SHOW THAT THE
AIR MASS WILL BE SLOW TO SATURATE BELOW 700 MB...ESPECIALLY OVER
THE EASTERN PART OF THE FORECAST AREA. LAYER Q VECTOR CONVERGENCE
IS ALSO NOT PARTICULARLY IMPRESSIVE...THOUGH LOW LEVEL
FRONTOGENESIS IS A LITTLE BETTER FROM 00Z-06Z. BOTTOM LINE ON THIS
FIRST WAVE...WILL CARRY POPS THROUGH 06Z WITH DECREASING CHANCES
AFTERWARDS. MOST PRECIPITATION WILL BE IN THE FORM OF RAIN...THOUGH
COLD AIR WILL EVENTUALLY ADVECT OVER THE AREA AFTER 06Z. AGAIN...THOUGH
...BEST DYNAMICS WILL BE EAST OF THE AREA BY THAT TIME...SO DO
NOT EXPECT MUCH SNOW ACCUMULATION.
THE FIRST SYSTEM WILL MOVE EAST FRIDAY...BUT THE NEXT MORE VIGOROUS
WAVE WILL MOVE OVER EASTERN COLORADO BY FRIDAY AFTERNOON. THIS
SYSTEM IS PROGGED TO HAVE EXCELLENT GEOSTROPHIC PARAMETERS THROUGH
SATURDAY TO PRODUCE WIDESPREAD PRECIPITATION. THE BEST WINDOW FOR
PRECIPITATION WILL OCCUR FROM 09Z SATURDAY THROUGH 03Z SUNDAY. BY
12Z SATURDAY...COLD AIR ADVECTION WILL BE OVER THE ENTIRE AREA...SO
EXPECT PRECIPITATION TYPE TO BE ALL SNOW SATURDAY. PROJECTED SNOW
TOTALS RANGE FROM TWO INCHES SOUTH TO SEVEN INCHES NORTH. THESE
PROJECTIONS ARE IN LINE WITH WINTER SEASON ANALOGS AND WPC ESTIMATES.
MODELS AND OTHER EXTERNAL GUIDANCE HAVE SHOWN DECENT RUN-TO-RUN
CONSISTENCY WITH THIS SYSTEM. NORTH WINDS AT 20 TO 30 KNOTS WILL
DEVELOP SATURDAY PRODUCING AREAS OF BLOWING SNOW.
THE SYSTEM WILL MOVE EAST SUNDAY...BUT WILL KEEP SOME LOW POPS OVER
THE EASTERN THIRD. YET ANOTHER SHORT WAVE TROUGH WILL MOVE OVER THE
HIGH PLAINS SUNDAY NIGHT AND MONDAY BRINGING ANOTHER CHANCE OF
PRECIPITATION. FOR TUESDAY AND WEDNESDAY...MODELS DIVERGE. FOR NOW...
WILL KEEP THE FORECAST DRY.
TEMPERATURES WILL BE SIGNIFICANTLY BELOW NORMAL FRIDAY THROUGH
MONDAY GIVEN ABUNDANT CLOUD COVER...SNOW...AND THE AMOUNT OF COLD
AIR WITH THE SYSTEM. MODELS SHOW WARMING TUESDAY AND WEDNESDAY.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z THURSDAY EVENING)
ISSUED AT 523 PM MDT WED MAR 20 2013
VFR TO MVFR CONDITIONS EXPECTED THROUGH THE TAF PERIOD. CLOUDY SKIES
THIS EVENING WITH SOME PATCHY FOG DEVELOPMENT POSSIBLE AS CLOUDS
DECREASE OVERNIGHT. IF FOG DOES DEVELOP MVFR CONDITIONS ARE EXPECTED
TO PREVAIL. WINDS ARE NOT A MAJOR CONCERN THROUGH THE TAF PERIOD AS
THEY WILL BE LIGHT /LESS THAN 12KTS/ AND GENERALLY OUT OF THE EAST
TO SOUTHEAST THROUGH THE PERIOD...WITH A FEW GUSTS TO 20KTS AT MCK
TOMORROW AFTERNOON. AS A WEAK DISTURBANCE MOVES INTO THE AREA
TOMORROW NIGHT THERE WILL BE AN INCREASE IN CLOUDS...BUT IT LOOKS
LIKE THE BEST CHANCE FOR PRECIPITATION WILL BE AFTER 00Z AND
THEREFOR OUTSIDE OF THIS TAF PERIOD.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
CO...NONE.
NE...NONE.
&&
$$
SHORT TERM...JRM
LONG TERM...MENTZER
AVIATION...JJM
AREA FORECAST DISCUSSION
NWS TOPEKA KS
1236 PM CDT TUE MAR 19 2013
...UPDATE TO AVIATION...
.DISCUSSION...
THE LATEST WATER VAPOR LOOP THIS MORNING AT 07Z SHOWS A WAVE MOVING
INTO SOUTHEAST WYOMING MOVING SOUTHEAST. THIS FEATURE WILL BRING
SOME ASCENT INTO NORTHEAST KANSAS BY LATE MORNING THROUGH THE
AFTERNOON HOURS. FORECAST SOUNDINGS FROM RAP SHOW STEEP LAPSE RATES
BELOW 750 MB THIS AFTERNOON. SOME ELEVATED INSTABILITY IS ALSO
PRESENT AND HAVE ADDED SHOWERS FOR PARTS OF NORTH CENTRAL AND
NORTHEAST KANSAS THIS AFTERNOON. LOW LEVELS ON SOUNDINGS SHOW THE
LOWER BOUNDARY LAYER MOISTENING WITH TIME. HIGHS TODAY WILL WARM
INTO THE MID 50S ACROSS THE SOUTHERN PORTIONS OF THE CWA WHILE THE
NORTHEAST CORNER WILL BE COOLEST WITH HIGHS IN THE UPPER 40S.
TONIGHT THROUGH WEDNESDAY BRINGS A DRY PERIOD TO THE FORECAST WITH A
NORTHWEST FLOW PATTERN ALOFT. TEMPERATURES WILL BE COOLER ON
WEDNESDAY WITH HIGH PRESSURE OVER NORTH CENTRAL AND NORTHEAST
KANSAS. EXPECTING HIGHS IN THE 40S.
WARM ADVECTION AND MOISTURE RETURN BEGINS IN EARNEST ALONG WITH
ISENTROPIC LIFT IN WESTERN AND CENTRAL KANSAS. BEST MOISTURE FOR ANY
PRECIPITATION REMAINS MAINLY WEST OF HIGHWAY 81 AND HAVE ADJUSTED
POPS WEDNESDAY NIGHT FURTHER WEST AND TRIMMED FURTHER EAST.
ISENTROPIC LIFT SHIFTS FURTHER EAST THURSDAY MORNING WITH MOISTURE
ADVECTION MAXIMIZED IN THE AFTERNOON HOURS. MODELS ARE IN AGREEMENT
WITH A SHORTWAVE MOVING OUT OF THE ROCKIES AND ACROSS KANSAS
THURSDAY AND THURSDAY NIGHT. BEST FOCUS FOR PRECIPITATION WILL BE
ACROSS EAST CENTRAL KANSAS. WITH WARMER TEMPERATURE PROFILES EXPECT
MORE OF A MIX OF PRECIPITATION TYPES THURSDAY AFTERNOON WITH THE
NORTHEAST REMAINING COLD ENOUGH FOR SNOW BUT EXPECT A MIX OF
RAIN...SLEET AND SNOW ACROSS NORTH CENTRAL AND NORTHEAST KANSAS.
WENT WITH A BLEND OF THE ECMWF...GEM AND GFS THROUGH FRIDAY THEN
WITH THE ECMWF AND GEM OVER THE WEEKEND. EXPECT THAT AROUND 2 INCHES
OR LESS OF ACCUMULATION AS THE SNOW WILL BE WET WITH SNOW/WATER
RATIO OF 6 TO 1 UP TO 9 TO 1...MELTING AND SOIL TEMPERATURES IN THE
MID AND UPPER 40S.
THE ECMWF AND GEM ARE IN GOOD AGREEMENT WITH THE UPPER TROUGH AXIS
MOVING THROUGH THE PLAINS ON SATURDAY NIGHT AND SUNDAY. THEY TAKE A
FURTHER SOUTH AND EAST TRACK THAN THE GFS WITH THE MID AND UPPER
LEVEL FEATURES. DEFORMATION ZONE WILL LAY ACROSS NORTHEAST AND EAST
CENTRAL KANSAS SATURDAY NIGHT AND SUNDAY. TEMPERATURE PROFILES
SUGGEST ALL SNOW SATURDAY NIGHT WITH A MIX OF RAIN AND SNOW SOUTH OF
I-70 SUNDAY WITH SNOW NORTH AND SOME ACCUMULATING SNOW IS POSSIBLE.
MODIFIED TEMPERATURES THURSDAY NIGHT AND FRIDAY NIGHT DUE TO CLOUDS
AND LIGHT PRECIPITATION. ANOTHER UPPER TROUGH IS FORECAST TO MOVE
INTO THE ROCKIES ON TUESDAY AND MAY BRING SOME MORE WINTER TYPE
WEATHER WITH IT.
53
&&
.AVIATION...
BAND OF LIGHT TO MODERATE SNOW HAS SET UP ACROSS THE TOPEKA AND
MANHATTAN TERMINALS. EXPECT THIS SNOW TO PERSIST THROUGH AT LEAST
22Z. EXPECT A GRADUAL DISSIPATION OF THE SNOW LATER THIS
EVENING...HOWEVER IN THE MEAN TIME IFR CIGS AND VIS WILL BE LIKELY
THROUGH AROUND 21Z TO 22Z. AFTER 00Z CONDITIONS SHOULD IMPROVE
BACK TO VFR FOR REMAINDER OF THE TAF PERIOD.
JL
&&
.TOP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS TOPEKA KS
643 AM CDT TUE MAR 19 2013
...UPDATE TO AVIATION...
.DISCUSSION...
THE LATEST WATER VAPOR LOOP THIS MORNING AT 07Z SHOWS A WAVE MOVING
INTO SOUTHEAST WYOMING MOVING SOUTHEAST. THIS FEATURE WILL BRING
SOME ASCENT INTO NORTHEAST KANSAS BY LATE MORNING THROUGH THE
AFTERNOON HOURS. FORECAST SOUNDINGS FROM RAP SHOW STEEP LAPSE RATES
BELOW 750 MB THIS AFTERNOON. SOME ELEVATED INSTABILITY IS ALSO
PRESENT AND HAVE ADDED SHOWERS FOR PARTS OF NORTH CENTRAL AND
NORTHEAST KANSAS THIS AFTERNOON. LOW LEVELS ON SOUNDINGS SHOW THE
LOWER BOUNDARY LAYER MOISTENING WITH TIME. HIGHS TODAY WILL WARM
INTO THE MID 50S ACROSS THE SOUTHERN PORTIONS OF THE CWA WHILE THE
NORTHEAST CORNER WILL BE COOLEST WITH HIGHS IN THE UPPER 40S.
TONIGHT THROUGH WEDNESDAY BRINGS A DRY PERIOD TO THE FORECAST WITH A
NORTHWEST FLOW PATTERN ALOFT. TEMPERATURES WILL BE COOLER ON
WEDNESDAY WITH HIGH PRESSURE OVER NORTH CENTRAL AND NORTHEAST
KANSAS. EXPECTING HIGHS IN THE 40S.
WARM ADVECTION AND MOISTURE RETURN BEGINS IN EARNEST ALONG WITH
ISENTROPIC LIFT IN WESTERN AND CENTRAL KANSAS. BEST MOISTURE FOR ANY
PRECIPITATION REMAINS MAINLY WEST OF HIGHWAY 81 AND HAVE ADJUSTED
POPS WEDNESDAY NIGHT FURTHER WEST AND TRIMMED FURTHER EAST.
ISENTROPIC LIFT SHIFTS FURTHER EAST THURSDAY MORNING WITH MOISTURE
ADVECTION MAXIMIZED IN THE AFTERNOON HOURS. MODELS ARE IN AGREEMENT
WITH A SHORTWAVE MOVING OUT OF THE ROCKIES AND ACROSS KANSAS
THURSDAY AND THURSDAY NIGHT. BEST FOCUS FOR PRECIPITATION WILL BE
ACROSS EAST CENTRAL KANSAS. WITH WARMER TEMPERATURE PROFILES EXPECT
MORE OF A MIX OF PRECIPITATION TYPES THURSDAY AFTERNOON WITH THE
NORTHEAST REMAINING COLD ENOUGH FOR SNOW BUT EXPECT A MIX OF
RAIN...SLEET AND SNOW ACROSS NORTH CENTRAL AND NORTHEAST KANSAS.
WENT WITH A BLEND OF THE ECMWF...GEM AND GFS THROUGH FRIDAY THEN
WITH THE ECMWF AND GEM OVER THE WEEKEND. EXPECT THAT AROUND 2 INCHES
OR LESS OF ACCUMULATION AS THE SNOW WILL BE WET WITH SNOW/WATER
RATIO OF 6 TO 1 UP TO 9 TO 1...MELTING AND SOIL TEMPERATURES IN THE
MID AND UPPER 40S.
THE ECMWF AND GEM ARE IN GOOD AGREEMENT WITH THE UPPER TROUGH AXIS
MOVING THROUGH THE PLAINS ON SATURDAY NIGHT AND SUNDAY. THEY TAKE A
FURTHER SOUTH AND EAST TRACK THAN THE GFS WITH THE MID AND UPPER
LEVEL FEATURES. DEFORMATION ZONE WILL LAY ACROSS NORTHEAST AND EAST
CENTRAL KANSAS SATURDAY NIGHT AND SUNDAY. TEMPERATURE PROFILES
SUGGEST ALL SNOW SATURDAY NIGHT WITH A MIX OF RAIN AND SNOW SOUTH OF
I-70 SUNDAY WITH SNOW NORTH AND SOME ACCUMULATING SNOW IS POSSIBLE.
MODIFIED TEMPERATURES THURSDAY NIGHT AND FRIDAY NIGHT DUE TO CLOUDS
AND LIGHT PRECIPITATION. ANOTHER UPPER TROUGH IS FORECAST TO MOVE
INTO THE ROCKIES ON TUESDAY AND MAY BRING SOME MORE WINTER TYPE
WEATHER WITH IT.
53
&&
.AVIATION...
FOR 12Z TAFS...CONDITIONS SHOULD REMAIN VFR THROUGH THE TAF PERIOD.
A WEAK WAVE WILL PASS OVER THE AREA TODAY...WHICH COULD BRING A FEW
FLURRIES OR SPRINKLES THIS MORNING ACROSS NORTHEAST KANSAS AND
POSSIBLY A FEW LIGHT RAIN SHOWERS DURING THE AFTERNOON HOURS.
HOWEVER...CONFIDENCE REMAINS LOW IN THE PROBABILITY OF ANY LIGHT
SHOWERS REACHING AS FAR SOUTH AS THE TAF SITES...SO HAVE KEPT ANY
MENTION OUT OF THE TAFS AT THIS TIME. IF ANY RAIN SHOWERS MANAGE TO
DEVELOP NEAR THE TAF SITES...CIGS COULD BRIEFLY APPROACH BORDERLINE
MVFR/VFR CONDITIONS. MID-LEVEL CLOUDS WILL BEGIN TO SCATTER OUT BY THIS
EVENING AS THE WAVE PASSES EAST OF THE AREA...WITH WINDS SHIFTING
FROM WEST TO NORTHWEST.
ACH
&&
.TOP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS TOPEKA KS
338 AM CDT TUE MAR 19 2013
.DISCUSSION...
THE LATEST WATER VAPOR LOOP THIS MORNING AT 07Z SHOWS A WAVE MOVING
INTO SOUTHEAST WYOMING MOVING SOUTHEAST. THIS FEATURE WILL BRING
SOME ASCENT INTO NORTHEAST KANSAS BY LATE MORNING THROUGH THE
AFTERNOON HOURS. FORECAST SOUNDINGS FROM RAP SHOW STEEP LAPSE RATES
BELOW 750 MB THIS AFTERNOON. SOME ELEVATED INSTABILITY IS ALSO
PRESENT AND HAVE ADDED SHOWERS FOR PARTS OF NORTH CENTRAL AND
NORTHEAST KANSAS THIS AFTERNOON. LOW LEVELS ON SOUNDINGS SHOW THE
LOWER BOUNDARY LAYER MOISTENING WITH TIME. HIGHS TODAY WILL WARM
INTO THE MID 50S ACROSS THE SOUTHERN PORTIONS OF THE CWA WHILE THE
NORTHEAST CORNER WILL BE COOLEST WITH HIGHS IN THE UPPER 40S.
TONIGHT THROUGH WEDNESDAY BRINGS A DRY PERIOD TO THE FORECAST WITH A
NORTHWEST FLOW PATTERN ALOFT. TEMPERATURES WILL BE COOLER ON
WEDNESDAY WITH HIGH PRESSURE OVER NORTH CENTRAL AND NORTHEAST
KANSAS. EXPECTING HIGHS IN THE 40S.
WARM ADVECTION AND MOISTURE RETURN BEGINS IN EARNEST ALONG WITH
ISENTROPIC LIFT IN WESTERN AND CENTRAL KANSAS. BEST MOISTURE FOR ANY
PRECIPITATION REMAINS MAINLY WEST OF HIGHWAY 81 AND HAVE ADJUSTED
POPS WEDNESDAY NIGHT FURTHER WEST AND TRIMMED FURTHER EAST.
ISENTROPIC LIFT SHIFTS FURTHER EAST THURSDAY MORNING WITH MOISTURE
ADVECTION MAXIMIZED IN THE AFTERNOON HOURS. MODELS ARE IN AGREEMENT
WITH A SHORTWAVE MOVING OUT OF THE ROCKIES AND ACROSS KANSAS
THURSDAY AND THURSDAY NIGHT. BEST FOCUS FOR PRECIPITATION WILL BE
ACROSS EAST CENTRAL KANSAS. WITH WARMER TEMPERATURE PROFILES EXPECT
MORE OF A MIX OF PRECIPITATION TYPES THURSDAY AFTERNOON WITH THE
NORTHEAST REMAINING COLD ENOUGH FOR SNOW BUT EXPECT A MIX OF
RAIN...SLEET AND SNOW ACROSS NORTH CENTRAL AND NORTHEAST KANSAS.
WENT WITH A BLEND OF THE ECMWF...GEM AND GFS THROUGH FRIDAY THEN
WITH THE ECMWF AND GEM OVER THE WEEKEND. EXPECT THAT AROUND 2 INCHES
OR LESS OF ACCUMULATION AS THE SNOW WILL BE WET WITH SNOW/WATER
RATIO OF 6 TO 1 UP TO 9 TO 1...MELTING AND SOIL TEMPERATURES IN THE
MID AND UPPER 40S.
THE ECMWF AND GEM ARE IN GOOD AGREEMENT WITH THE UPPER TROUGH AXIS
MOVING THROUGH THE PLAINS ON SATURDAY NIGHT AND SUNDAY. THEY TAKE A
FURTHER SOUTH AND EAST TRACK THAN THE GFS WITH THE MID AND UPPER
LEVEL FEATURES. DEFORMATION ZONE WILL LAY ACROSS NORTHEAST AND EAST
CENTRAL KANSAS SATURDAY NIGHT AND SUNDAY. TEMPERATURE PROFILES
SUGGEST ALL SNOW SATURDAY NIGHT WITH A MIX OF RAIN AND SNOW SOUTH OF
I-70 SUNDAY WITH SNOW NORTH AND SOME ACCUMULATING SNOW IS POSSIBLE.
MODIFIED TEMPERATURES THURSDAY NIGHT AND FRIDAY NIGHT DUE TO CLOUDS
AND LIGHT PRECIPITATION. ANOTHER UPPER TROUGH IS FORECAST TO MOVE
INTO THE ROCKIES ON TUESDAY AND MAY BRING SOME MORE WINTER TYPE
WEATHER WITH IT.
53
&&
.AVIATION...
WILL MAINTAIN VFR TAF FCSTS THROUGH THE PERIOD WITH BKN-OVC CIGS
AROUND 7KFT WITH DRY AIR HOLDING JUST BLO THIS DECK. ALTHOUGH
SOME SLIGHT CHANCE FOR SPRINKLES/LIGHT RAIN SHOWERS AFT 18Z...THE
BETTER FOCUS APPEARS WILL BE NORTH OF THE TAF SITES. LIGHT EAST TO
NORTHEAST WINDS UNDER 8 KTS WILL CONTINUE.
&&
.TOP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
416 PM EDT TUE MAR 19 2013
.SHORT TERM...(THIS EVENING THROUGH WEDNESDAY)
ISSUED AT 415 PM EDT TUE MAR 19 2013
12Z RAOBS/LATEST WV IMAGERY AND RUC ANALYSIS SHOW DEEP CLOSED LO
CENTERED OVER ERN LK SUP DOWNSTREAM OF RDG ALONG THE W COAST. DEEP
CYC NW FLOW OF COLD AIR ARND THE SFC LO NEAR WAWA ONTARIO IS
DOMINATING THE CWA...CAUSING LES OVER MAINLY THE WRN ZNS EARLY THIS
AFTN AS -16C H85 TEMPS SHOWN AT INL AT 12Z MOVE OVER THE LAKE. WITH
SHARPENING PRES GRADIENT BTWN PRES RISE CENTER OVER NRN MN AND PRES
FALLS OVER SE ONTARIO TO THE E OF THE SFC LO...THE NW WINDS ARE
STRENGTHENING...WITH WIND GUSTS UP TO 40 MPH REPORTED CAUSING
EXTENSIVE BLSN. THE SN HAS TAPERED OFF OVER THE FAR W AND SCENTRAL
WITH THE ADVECTION OF DRIER AIR OBSVD IN MN AT 12Z/WELL DEPICTED ON
THE 12Z MPX RAOB AND DOWNSLOPE FLOW INTO THE SCENTRAL. PUBLIC
REPORTS INDICATE AS MUCH AS 18 INCHES OF SN HAS FALLEN OVER THE HIER
TERRAIN OF THE W. FARTHER UPSTREAM...ANOTHER SHRTWV IS DIGGING SEWD
THRU LK WINNIPEG.
MAIN FCST CONCERNS THRU WED REMAIN LES/WIND TRENDS AND GOING
HEADLINES AS CLOSED LO DRIFTS ONLY SLOWLY TO THE ENE THRU SE CANADA.
LATE TODAY/TNGT...OVERALL DEEP CYC NW FLOW ARND SLOWLY DEPARTING LO
IS PROGGED TO LINGER AND CAUSE PERSISTENT LES IN THE NW WIND SN
BELTS. THE LES INTENSITY OVER THE FAR W...ESPECIALLY WHERE THE FETCH
ACRS THE OPEN WATER IS SHORTER NEAR IWD...HAS DIMINISHED AS DRIER
AIR IN MN SLID EWD. THIS DRY AIR WL IMPACT MAINLY THE AREAS NEAR THE
WI BORDER. SO THE SCENTRAL SHOULD REMAIN DRY WITH DOWNSLOPING DRIER
FLOW. BUT LATER TNGT...SHRTWV NOW NEAR LK WINNIPEG IS FCST TO DIG
SEWD...CAUSING THE LLVL FLOW TO VEER A BIT AND BRING BACK A RETURN
OF DEEPER MSTR OVER THE ENTIRE CWA ON THE CYC SIDE OF ITS TRACK.
THESE TRENDS SHOULD CAUSE LES TO PICK UP AGAIN AT IWD FOLLOWING A
BREAK THIS EVNG. IN THE NW WIND SN BELTS E OF MQT...THE ARRIVAL OF
COLDER AIR WL LIKELY ENHANCE THE INTENSITY OF THE LES THRU THE NGT
WITH FVRBL WNW LLVL FLOW SHIFTING NW. ANOTHER FACTOR FAVORING HEAVY
SN IS FVRBL ALIGNMENT OF FCST UVV MAX WITHIN THE DGZ EVEN IF STRONG
WINDS THAT CAUSE A BREAK UP OF THE DENDRITES ACT TO REDUCE THE
SN/WATER RATIOS A BIT. BUT THESE STRONG WINDS WL CAUSE EXTENSIVE
BLSN/REDUCED VSBY ESPECIALLY NEAR LK SUP...EVEN WHEN THE LES IS NOT
FALLING HEAVILY.
WED...AS THE CLOSED LO SLOWLY DRIFTS TO THE E...CYC NW FLOW IS
PROGGED TO VEER SLOWLY TO THE NNW. WITH THE ARRIVAL OF SOMEWHAT
WARMER ATLANTIC AIR FM THE NE ARND INTENSE LO PER THE 12Z GFS AND
ESPECIALLY THE NAM...DEEP MSTR IS FCST TO LINGER. ALTHOUGH THE
WARMING WITH H85 TEMPS PROGGED TO RISE TOWARD -10C OVER FAR ERN LK
SUP MIGHT TEND TO REDUCE LES INTENSITY...THE ARRIVAL OF SOME LARGER
SCALE QVECTOR CNVGC/MAINTENANCE OF DEEPER MSTR ASSOCIATED SOME
ISENTROPIC ASCENT WL RETAIN A LK ENHANCED COMPONENT. ALTHOUGH THE
BEST CHC FOR CONTINUED DRY WX WL BE OVER THE SCENTRL...FCST SDNGS
INDICATE THE MSTR WL BE DEEP ENUF TO SUPPORT AT LEAST SCT -SHSN.
SOME OF THE GUIDANCE SUGGESTS SOME DRIER AIR MAY ARRIVE OVER THE W
ON WED AFTN... BUT SLOW MOTION OF THE CLOSED LO TO THE E FAVORS THE
MODELS THAT SHOW A SLOWER EWD PROGRESSION OF THIS DRYING.
GOING HEADLINES LOOK TO BE IN GOOD SHAPE AS LONG DURATION EVENT WL
ADD TO SN ACCUMS THAT HAVE ALREADY HIT WARNING TOTALS IN MOST AREAS
WHERE THESE HEADLINES HAVE BEEN IN EFFECT. EXPECT STORM TOTAL SN TO
REACH 24 INCHES OR MORE OVER THE HIER TERRAIN OF THE W.
.LONG TERM...(WEDNESDAY NIGHT THROUGH TUESDAY)
ISSUED AT 415 PM EDT TUE MAR 19 2013
LOOK FOR A SLOW AND STEADY RISE IN TEMPERATURES THROUGH THE PERIOD
AS WE SLOWLY LOSE THE INFLUENCE OF THE NEARBY 500MB TROUGH.
THE ELONGATED 500MB TROUGH WILL EXTEND FROM JUST NE OF MAINE TO
LOWER MI...AND SOUTHERN UPPER PORTIONS OF UPPER MI AT 00Z
THURSDAY...WITH A SIZABLE RIDGE STRETCHING ACROSS WYOMING AND THE
WESTERN DAKOTAS UP THROUGH SASKATCHEWAN.
WHILE THE 500MB RIDGE WILL PUSH INTO WESTERN UPPER MI/LAKE SUPERIOR
FRIDAY...IT WILL TAKE UNTIL FRIDAY NIGHT UNTIL THE NEARLY STEADY
STATE LOW OVER THE EAST PUSHES OFFSHORE. THE 19/00Z RUNS OF THE
ECMWF AND CANADIAN HOLD ONTO THE TROUGH ACROSS EASTERN UPPER MI A
BIT LONGER THAN THE GFS /BY ROUGHLY 6HRS/. THE SFC TROUGH WILL
LIKELY LINGER ACROSS EASTERN MICHIGAN THROUGH 12Z FRIDAY. THE RESULT
WILL BE CONTINUED LAKE EFFECT SNOW SHOWERS FOR NORTHERLY-NNW WIND
FAVORED LOCATIONS NEAR LAKE SUPERIOR. 850MB TEMPS WILL MODERATE FROM
THE -12 TO -15C AT 00Z THURSDAY TO AROUND -8C BY DAYBREAK FRIDAY.
EXPECT QUICKLY DIMINISHING LAKE EFFECT SNOW SHOWERS AFTER THURSDAY
AFTERNOON...WITH LOWERING INVERSION HEIGHTS
500MB RIDGING WILL BE THE RULE FRIDAY NIGHT THROUGH AT LEAST
SATURDAY NIGHT.
LOOK FOR A CLUSTERED AREA OF LOW PRESSURE CENTERED NEAR MONTANA AT
00Z SATURDAY WILL DIVIDE FRIDAY NIGHT...WITH THE NORTHERN LOW
SPINNING IN PLACE...AND THE SOUTHERN EXTENT OF THE TROUGH DIVING
ACROSS TEXAS AND OKLAHOMA BY LATE SATURDAY AFTERNOON/SATURDAY NIGHT.
THE 00Z RUNS OF THE GFS AND ECMWF WERE FAIRLY CONSISTENT WITH THE
TRACK OF THE SOUTHERN TROUGH...MOVING IT OVER KENTUCKY AND WEST
VIRGINIA BY DAYBREAK MONDAY...WITH THE RIDGE WEAKENING BUT STILL
REMAINING OVER LAKE SUPERIOR AND UPPER MICHIGAN THROUGH AT LEAST
SUNDAY NIGHT. THE 12Z GFS CAME IN WITH THE 500MB LOW SHIFTED APPROX
250MI TO THE NORTHWEST OF THE 00Z RUN TRACK...WHICH WOULD BRING IT
ACROSS LOWER MI AT 00Z TUESDAY. THIS WOULD RESULT IN STRONGER WINDS
FOR CENTRAL AND EASTERN AREAS...AS WELL AS UPSLOPE LES NORTH CENTRAL
WITH SYNOPTIC SNOW HUGGING THE EASTERN COUNTIES.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z WEDNESDAY AFTERNOON)
ISSUED AT 126 PM EDT TUE MAR 19 2013
WITH A COLD CYC NW FLOW CONTINUING ARND LO PRES DEPARTING SLOWLY
THRU SE ONTARIO THIS FCST PERIOD...EXPECT SHSN TO IMPACT CMX/
IWD...WITH IFR/LIFR CONDITIONS PREDOMINATING. THE WORST CONDITIONS
TO VLIFR ARE MOST LIKELY AT THE MORE EXPOSED CMX LOCATION THRU THIS
EVNG WITH DEEPER MSTR/STRONGER WINDS. BEST OPPORTUNITY FOR MORE
IMPROVED MVFR CONDITIONS WL BE AT IWD THIS AFTN/EVNG...WHEN DRIER
AIR MOVING ESE FM MN WL LIMIT LES INTENSITY. AT SAW...DOWNSLOPING
NW WINDS SHOULD RESULT IN MAINLY MVFR CONDITIONS THRU THE FCST
PERIOD.
&&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 415 PM EDT TUE MAR 19 2013
EXPECT NW GALES/HEAVY FREEZING SPRAY TO LINGER THRU AT LEAST WED
MORNING AS DEEP LO PRES OVER SE ONTARIO EDGES SLOWLY TO THE E AND A
COLD...GUSTY NW WIND CONTINUES. WINDS/FREEZING SPRAY ARE LIKELY TO
DIMINISH OVER THE W WED AFTERNOON FARTHER FROM THE SLOWLY RETREATING
LO.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
WINTER STORM WARNING UNTIL 8 PM EDT /7 PM CDT/ WEDNESDAY FOR
MIZ001>004-009-084.
WINTER STORM WARNING UNTIL 8 AM EDT THURSDAY FOR MIZ006-007-085.
LAKE SUPERIOR...
HEAVY FREEZING SPRAY WARNING UNTIL 8 PM EDT /7 PM CDT/ WEDNESDAY
FOR LSZ162-240>245-248>251-263>267.
GALE WARNING UNTIL 2 PM EDT /1 PM CDT/ WEDNESDAY FOR LSZ162-
243>245-249>251-263>267.
GALE WARNING UNTIL 6 AM EDT WEDNESDAY FOR LSZ248.
GALE WARNING UNTIL 11 PM EDT THIS EVENING FOR LSZ246-247.
GALE WARNING UNTIL 8 PM EDT /7 PM CDT/ THIS EVENING FOR
LSZ240>242.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...KC
LONG TERM...KF
AVIATION...KC
MARINE...KC
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
127 PM EDT TUE MAR 19 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 547 AM EDT TUE MAR 19 2013
WATER VAPOR IMAGERY AND RUC ANALYSIS SHOW TROF EXTENDING FROM SCNTRL
CANADA INTO THE GREAT LAKES. SNOW IS DIMINISHING ACROSS UPPER MI AS
SHORTWAVE SLIPS E OF THE AREA. AT THE SFC...LOW PRES IS LOCATED OVER
CNTRL LAKE SUPERIOR. ON THE BACKSIDE OF THE LOW...STRONG NW WINDS
ARE DEVELOPING OVER FAR WRN LAKE SUPERIOR AND WILL BE REACHING UPPER
MI SHORTLY.
FCST THINKING HAS NOT CHANGED MUCH SINCE YESTERDAY. STRONG/GUSTY NW
WINDS WILL DEVELOP FROM W TO E TODAY AS SFC LOW PRES DRIFTS E. DEEP
MOISTURE/CONVERGENT CYCLONIC WNW FLOW AND INCREASINGLY COLDER AIR
WILL YIELD MDT/HVY LAKE ENHANCED SNOW DEVELOPING EARLY THIS MORNING
OVER THE W AND SPREADING TO AREAS FROM AROUND MUNISING EASTWARD LATE
MORNING/AFTN. WITH FCST SOUNDINGS SHOWING A DEEP DGZ OVER
GOGEBIC/ONTONAGON COUNTIES...SNOW SHOULD BE VERY HVY AT TIMES IN
THAT AREA TODAY. MEANWHILE...BEST LOW-LEVEL CONVERGENCE WILL SET UP
ACROSS NRN ONTONAGON COUNTY/SRN HALF OF HOUGHTON COUNTY FOR MUCH OF
TODAY/TONIGHT. BOTH FACTORS WILL RESULT IN GREATEST SNOW
ACCUMULATIONS TODAY/TONIGHT OCCURRING FROM THE HIGHER TERRAIN JUST N
OF KIWD TO THE PORCUPINE MOUNTAINS...ROCKLAND...TWIN LAKES AND
PAINESDALE. AMOUNTS UPWARDS OF 18 INCHES FROM 12Z TODAY-12Z WED SEEM
LIKELY IN THOSE AREAS...BUT WOULDN`T BE SURPRISED TO SEE MORE THAN
THAT. FARTHER N ON THE KEWEENAW...AMOUNTS WILL LIKELY TREND DOWN TO
A FOOT OR LESS UNDER WEAKER LOW-LEVEL CONVERGENCE. STRONG BOUNDARY
LAYER WINDS WILL SPREAD STEADIER SNOWS INTO BARAGA COUNTY WITH
ACCUMULATIONS LIKELY REACHING WARNING CRITERIA OVER HIGH TERRAIN. TO
THE E...AIR MASS WON`T BE QUITE AS COLD AND MAY RESULT IN DGZ BEING
DISPLACED A LITTLE ABOVE BEST UPWARD MOTION TODAY...BUT DGZ BECOMES
BETTER POSITIONED IN CONVECTIVE LAYER TONIGHT. LOW-LEVEL CONVERGENCE
IS NOT AS STRONG AS OVER THE W THROUGHOUT TODAY/TONIGHT. THESE
FACTORS SHOULD KEEP SNOW ACCUMULATIONS DOWN TO THE 6-12 INCH RANGE
BY WED MORNING WITH THE GREATEST AMOUNTS E OF MUNISING AND N/NW OF
KERY. WINDS WILL BE A SIGNIFICANT FACTOR. WITH GUSTS OF 30-40MPH...
ALONG LAKE SUPERIOR AND OVER THE KEWEENAW...BLSN WILL BE A MAJOR
ISSUE WITH WHITE-OUTS AT TIMES DUE TO HVY SNOW/BLSN. BLSN WILL BE
MOST SIGNIFICANT OVER THE KEWEENAW PENINSULA...WITH WORST CONDITIONS
THIS AFTN/EVENING.
AWAY FROM HEADLINE AREAS...-SN EARLY WILL TRANSITION TO SCT -SHSN.
DOWNSLOPE WWN WINDS WILL LIKELY BRING AN END TO -SHSN OVER THE
SCNTRL THIS AFTN.
.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 547 AM EDT TUE MAR 19 2013
MODELS ADVERTISE PRETTY STRAIGHT FORWARD LARGE SCALE PATTERN FOR THE
LONG TERM PERIOD. AGREEMENT IN THE PRIMARY FEATURES IN THE LARGER
SCALE FLOW IS GOOD WHICH LEADS TO HIGHER CONFIDENCE FORECAST.
UPPER TROUGH FROM SOUTHERN QUEBEC/NEW ENGLAND WESTWARD ACROSS GREAT
LAKES IS MAIN FEATURE THROUGH LATE THIS WEEK. AS MOST OF UPPER JET
ENERGY ROUNDS BASE OF TROUGH...EXPECT TROUGH TO RAMBLE SLOWLY EAST
BY FRIDAY WHICH RESULTS IN HEIGHTS GRADUALLY RISING OVER UPPER GREAT
LAKES INTO NEXT WEEKEND. SFC PATTERN WELL AGREED UPON AS WELL. SFC
LOW STARTS OUT JUST EAST OF LK SUPERIOR ON WEDNESDAY THEN SHIFTS
INTO SOUTHERN QUEBEC BY THURSDAY WITH TROUGHING ENHANCED BY THE
LAKES LINGERING ACROSS LK SUPERIOR REGION. NO SIGNIFICANT CHANGE
TO PREVIOUS FCST THINKING THAT MODERATE TO AT TIMES HEAVY LK EFFECT
SNOWS IMPACT MAINLY NW SNOW BELTS OF LK SUPERIOR ON WEDNESDAY. DEEP
MOISTURE TIED TO TROUGH LINGERS AND SOUNDINGS ACTUALLY SHOW COLDEST
925-850MB TEMPS THROUGH WEDNESDAY. SFC-H95 CONVERGENCE PEGS HIGHER
TERRAIN OF WESTERN CWA ROUGHLY IRONWOOD-WAKEFIELD THROUGH TWIN LAKES
AND ATLANTIC MINE THOUGH STRONG BLYR WINDS OVER 30 KTS WILL PUSH
HEAVIER SNOW SHOWERS FARTHER INLAND THAN NORMALLY OCCURS WITH SIMILAR
WIND DIRECTION.
CONVERGENCE ALSO STRONG OVER EAST...ROUGHLY MUNISING TO NORTH OF
NEWBERRY. AGAIN STRONG WINDS MAY PUSH AT LEAST MODERATE SNOW SHOWERS
AS FAR SOUTH AS US-2 IN SCHOOLCRAFT COUNTY. HIGHEST SNOW AMOUNTS /UP
TO 6 INCHES IN 12 HRS/ EXPECTED ON WEDNESDAY. SHORTWAVE TROUGH DROPS
THROUGH THE OVERALL MEAN TROUGHING ON WEDNESDAY NIGHT. MODELS HAVE
BEEN SHOWING THIS AWHILE NOW. MAIN RESULT WILL BE WINDS SHIFTING TO
MORE NNW-N DIRECTION VERSUS NW WINDS SEEN THROUGH WEDNESDAY. SNOW
OVER NORTHWEST-WEST MARQUETTE COUNTY COULD AFFECT MORE OF THE COUNTY
WITH MORE NORTHERLY WINDS. SOUNDINGS DO INDICATE DECENT DRYING IN
WAKE OF THE WAVE IN H8-H7 LAYER BY LATER THURSDAY MORNING...BUT MOST
OF LAKE EFFECT CONVECTIVE LAYER IS WITHIN DGZ...SO SLR/S AROUND 20:1
WILL BOOST AMOUNTS. POSSIBLE THAT ADVY LEVEL SNOW AMOUNTS COULD
OCCUR LATER WEDNESDAY EVENING THROUGH MID MORNING THURSDAY OVER
MARQUETTE COUNTY...IMPACTING THU MORNING COMMUTE. LATER SHIFTS MAY
NEED TO CONSIDER HEADLINES FOR MARQUETTE COUNTY FOR THIS POTENTIAL.
DRYING SUBSIDENCE BEGINS TO TAKE BITE INTO LK EFFECT OVER WESTERN
CWA ON THURSDAY AFTN. LOCAL WRF PREFERRED WITH LOOK OF LK EFFECT
POPS/QPF THROUGH THURSDAY MORNING AND THIS INDICATES INVERSIONS
LOWERING TO LESS THAN 4KFT BY THURSDAY AFTN IN THE WEST. CURRENT
ENDING TIME OF 12Z THURSDAY FOR THE WEST LOOKING GOOD. SETUP A BIT
BETTER IN EAST THROUGH THURSDAY...BUT EVEN THERE...INVERSIONS LOWER
BLO 5KFT THOUGH THERE IS LINGERING MOISTURE BLO H7 INTO THURSDAY
EVENING. OVERALL...STRONG SUBSIDENCE/DRYING ABOVE INVERSION AND LACK
OF REAL COLD TEMPS WITHIN LK EFFECT MOIST LAYER POINTS TO
SIGNIFICANT DIMINISHING TREND TO LK EFFECT BY LATE THURSDAY
AFTN/EVENING.
EVEN SO...IT IS NOT UNTIL FRIDAY AND MAYBE EVEN AS LATE AS SATURDAY
BEFORE LOW-LEVEL FLOW OVER AREA BECOMES MORE ANTICYCLONIC AS HIGH
PRESSURE OVER NORTHERN CANADA EXPANDS INTO MANITOBA AND NORTHWEST
ONTARIO. NORTH WINDS OFF LK SUPERIOR AND TEMPS AROUND -8C KEEP
CLOUDS AND PERHAPS LGT FLURRIES GOING ON FRIDAY OVR NCNTRL UPR
MICHIGAN. AT SOME POINT...LK EFFECT WILL CEASE DUE TO INCREASING
LOW-LEVEL SHEAR AND SUBSIDENCE WITH CONTINUED WARMING TEMPS AT TOP
OF INVERSION. BY LATER IN THE WEEKEND LAST COUPLE RUNS OF GFS ARE
DEVELOPING WOUND UP SHORTWAVE/LOW PRESSURE SYSTEM IN THE CENTRAL
PLAINS. 12Z/18 MARCH ECMWF WAS MUCH MORE SUPPRESSED WITH SUCH A
SYSTEM RIDING IT ACROSS SOUTHERN TIER OF CONUS. 00Z ECMWF DID SHOW
MORE AMPLIFICATION BUT STILL KEEPS SYSTEM OVER SOUTHERN PORTION OF
OHIO VALLEY. GEM-NH/UKMET MORE WOUND UP NOW TOO...BUT LIKE ECMWF ARE
NOT NEAR AS NORTHWEST AS GFS. CAN NOT COMPLETELY COUNT OUT SOME SORT
OF SYSTEM AS TROUGHING IS PRESENT IN LARGE SCALE FROM WESTERN CANADA
INTO SOUTHERN PLAINS. PREFER THE LOOK OF WPC HAND DRAWN PROGS WITH
LOW TRACKING ACROSS SOUTHEAST CONUS AT THIS POINT. MAIN RESULT IS
QUIET WEATHER OVER UPR LAKES THROUGH THE UPCOMING WEEKEND WITH MORE
CLOUDS THAN SUNSHINE AND HIGH TEMPERATURES AT OR SLIGHTLY BLO NORMAL
IN THE LOW-MID 30S.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z WEDNESDAY AFTERNOON)
ISSUED AT 126 PM EDT TUE MAR 19 2013
WITH A COLD CYC NW FLOW CONTINUING ARND LO PRES DEPARTING SLOWLY
THRU SE ONTARIO THIS FCST PERIOD...EXPECT SHSN TO IMPACT CMX/
IWD...WITH IFR/LIFR CONDITIONS PREDOMINATING. THE WORST CONDITIONS
TO VLIFR ARE MOST LIKELY AT THE MORE EXPOSED CMX LOCATION THRU THIS
EVNG WITH DEEPER MSTR/STRONGER WINDS. BEST OPPORTUNITY FOR MORE
IMPROVED MVFR CONDITIONS WL BE AT IWD THIS AFTN/EVNG...WHEN DRIER
AIR MOVING ESE FM MN WL LIMIT LES INTENSITY. AT SAW...DOWNSLOPING
NW WINDS SHOULD RESULT IN MAINLY MVFR CONDITIONS THRU THE FCST
PERIOD.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 547 AM EDT TUE MAR 19 2013
AS LOW PRES OVER ERN LAKE SUPERIOR DRIFTS E TODAY AND TONIGHT...NW
GALES WHICH ARE CURRENTLY DEVELOPING OVER WRN LAKE SUPERIOR WILL
EXPAND E ACROSS THE LAKE TODAY. THE GALES WILL THEN CONTINUE INTO
WED OVER THE E HALF OF THE LAKE WHILE WINDS DIMINISH SLIGHTLY BELOW
GALES OVER THE W. WINDS WILL SLOWLY DIMINISH TO UNDER 25KT FROM W TO
E WED NIGHT/THU. THE COMBINATION OF COLD AIR/STRONG WINDS/HIGH WAVES
WILL LEAD TO PERIODS OF HVY FREEZING SPRAY THRU WED.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
WINTER STORM WARNING UNTIL 8 PM EDT /7 PM CDT/ WEDNESDAY FOR
MIZ001>004-009-084.
WINTER STORM WARNING UNTIL 8 AM EDT THURSDAY FOR MIZ006-007-085.
LAKE SUPERIOR...
HEAVY FREEZING SPRAY WARNING UNTIL 8 PM EDT WEDNESDAY FOR
LSZ243>245-248>251-264>267.
GALE WARNING UNTIL 2 PM EDT /1 PM CDT/ WEDNESDAY FOR LSZ162-263-
264-266-267.
GALE WARNING UNTIL 2 PM EDT WEDNESDAY FOR LSZ243>245-249>251-265.
HEAVY FREEZING SPRAY WARNING UNTIL 8 PM EDT /7 PM CDT/ WEDNESDAY
FOR LSZ162-240>242-263.
GALE WARNING UNTIL 6 AM EDT WEDNESDAY FOR LSZ248.
GALE WARNING UNTIL 11 PM EDT THIS EVENING FOR LSZ246-247.
GALE WARNING UNTIL 8 PM EDT /7 PM CDT/ THIS EVENING FOR
LSZ240>242.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...ROLFSON
LONG TERM...JLA
AVIATION...KC
MARINE...ROLFSON
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
728 AM EDT TUE MAR 19 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 547 AM EDT TUE MAR 19 2013
WATER VAPOR IMAGERY AND RUC ANALYSIS SHOW TROF EXTENDING FROM SCNTRL
CANADA INTO THE GREAT LAKES. SNOW IS DIMINISHING ACROSS UPPER MI AS
SHORTWAVE SLIPS E OF THE AREA. AT THE SFC...LOW PRES IS LOCATED OVER
CNTRL LAKE SUPERIOR. ON THE BACKSIDE OF THE LOW...STRONG NW WINDS
ARE DEVELOPING OVER FAR WRN LAKE SUPERIOR AND WILL BE REACHING UPPER
MI SHORTLY.
FCST THINKING HAS NOT CHANGED MUCH SINCE YESTERDAY. STRONG/GUSTY NW
WINDS WILL DEVELOP FROM W TO E TODAY AS SFC LOW PRES DRIFTS E. DEEP
MOISTURE/CONVERGENT CYCLONIC WNW FLOW AND INCREASINGLY COLDER AIR
WILL YIELD MDT/HVY LAKE ENHANCED SNOW DEVELOPING EARLY THIS MORNING
OVER THE W AND SPREADING TO AREAS FROM AROUND MUNISING EASTWARD LATE
MORNING/AFTN. WITH FCST SOUNDINGS SHOWING A DEEP DGZ OVER
GOGEBIC/ONTONAGON COUNTIES...SNOW SHOULD BE VERY HVY AT TIMES IN
THAT AREA TODAY. MEANWHILE...BEST LOW-LEVEL CONVERGENCE WILL SET UP
ACROSS NRN ONTONAGON COUNTY/SRN HALF OF HOUGHTON COUNTY FOR MUCH OF
TODAY/TONIGHT. BOTH FACTORS WILL RESULT IN GREATEST SNOW
ACCUMULATIONS TODAY/TONIGHT OCCURRING FROM THE HIGHER TERRAIN JUST N
OF KIWD TO THE PORCUPINE MOUNTAINS...ROCKLAND...TWIN LAKES AND
PAINESDALE. AMOUNTS UPWARDS OF 18 INCHES FROM 12Z TODAY-12Z WED SEEM
LIKELY IN THOSE AREAS...BUT WOULDN`T BE SURPRISED TO SEE MORE THAN
THAT. FARTHER N ON THE KEWEENAW...AMOUNTS WILL LIKELY TREND DOWN TO
A FOOT OR LESS UNDER WEAKER LOW-LEVEL CONVERGENCE. STRONG BOUNDARY
LAYER WINDS WILL SPREAD STEADIER SNOWS INTO BARAGA COUNTY WITH
ACCUMULATIONS LIKELY REACHING WARNING CRITERIA OVER HIGH TERRAIN. TO
THE E...AIR MASS WON`T BE QUITE AS COLD AND MAY RESULT IN DGZ BEING
DISPLACED A LITTLE ABOVE BEST UPWARD MOTION TODAY...BUT DGZ BECOMES
BETTER POSITIONED IN CONVECTIVE LAYER TONIGHT. LOW-LEVEL CONVERGENCE
IS NOT AS STRONG AS OVER THE W THROUGHOUT TODAY/TONIGHT. THESE
FACTORS SHOULD KEEP SNOW ACCUMULATIONS DOWN TO THE 6-12 INCH RANGE
BY WED MORNING WITH THE GREATEST AMOUNTS E OF MUNISING AND N/NW OF
KERY. WINDS WILL BE A SIGNIFICANT FACTOR. WITH GUSTS OF 30-40MPH...
ALONG LAKE SUPERIOR AND OVER THE KEWEENAW...BLSN WILL BE A MAJOR
ISSUE WITH WHITE-OUTS AT TIMES DUE TO HVY SNOW/BLSN. BLSN WILL BE
MOST SIGNIFICANT OVER THE KEWEENAW PENINSULA...WITH WORST CONDITIONS
THIS AFTN/EVENING.
AWAY FROM HEADLINE AREAS...-SN EARLY WILL TRANSITION TO SCT -SHSN.
DOWNSLOPE WWN WINDS WILL LIKELY BRING AN END TO -SHSN OVER THE
SCNTRL THIS AFTN.
.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 547 AM EDT TUE MAR 19 2013
MODELS ADVERTISE PRETTY STRAIGHT FORWARD LARGE SCALE PATTERN FOR THE
LONG TERM PERIOD. AGREEMENT IN THE PRIMARY FEATURES IN THE LARGER
SCALE FLOW IS GOOD WHICH LEADS TO HIGHER CONFIDENCE FORECAST.
UPPER TROUGH FROM SOUTHERN QUEBEC/NEW ENGLAND WESTWARD ACROSS GREAT
LAKES IS MAIN FEATURE THROUGH LATE THIS WEEK. AS MOST OF UPPER JET
ENERGY ROUNDS BASE OF TROUGH...EXPECT TROUGH TO RAMBLE SLOWLY EAST
BY FRIDAY WHICH RESULTS IN HEIGHTS GRADUALLY RISING OVER UPPER GREAT
LAKES INTO NEXT WEEKEND. SFC PATTERN WELL AGREED UPON AS WELL. SFC
LOW STARTS OUT JUST EAST OF LK SUPERIOR ON WEDNESDAY THEN SHIFTS
INTO SOUTHERN QUEBEC BY THURSDAY WITH TROUGHING ENHANCED BY THE
LAKES LINGERING ACROSS LK SUPERIOR REGION. NO SIGNIFICANT CHANGE
TO PREVIOUS FCST THINKING THAT MODERATE TO AT TIMES HEAVY LK EFFECT
SNOWS IMPACT MAINLY NW SNOW BELTS OF LK SUPERIOR ON WEDNESDAY. DEEP
MOISTURE TIED TO TROUGH LINGERS AND SOUNDINGS ACTUALLY SHOW COLDEST
925-850MB TEMPS THROUGH WEDNESDAY. SFC-H95 CONVERGENCE PEGS HIGHER
TERRAIN OF WESTERN CWA ROUGHLY IRONWOOD-WAKEFIELD THROUGH TWIN LAKES
AND ATLANTIC MINE THOUGH STRONG BLYR WINDS OVER 30 KTS WILL PUSH
HEAVIER SNOW SHOWERS FARTHER INLAND THAN NORMALLY OCCURS WITH SIMILAR
WIND DIRECTION.
CONVERGENCE ALSO STRONG OVER EAST...ROUGHLY MUNISING TO NORTH OF
NEWBERRY. AGAIN STRONG WINDS MAY PUSH AT LEAST MODERATE SNOW SHOWERS
AS FAR SOUTH AS US-2 IN SCHOOLCRAFT COUNTY. HIGHEST SNOW AMOUNTS /UP
TO 6 INCHES IN 12 HRS/ EXPECTED ON WEDNESDAY. SHORTWAVE TROUGH DROPS
THROUGH THE OVERALL MEAN TROUGHING ON WEDNESDAY NIGHT. MODELS HAVE
BEEN SHOWING THIS AWHILE NOW. MAIN RESULT WILL BE WINDS SHIFTING TO
MORE NNW-N DIRECTION VERSUS NW WINDS SEEN THROUGH WEDNESDAY. SNOW
OVER NORTHWEST-WEST MARQUETTE COUNTY COULD AFFECT MORE OF THE COUNTY
WITH MORE NORTHERLY WINDS. SOUNDINGS DO INDICATE DECENT DRYING IN
WAKE OF THE WAVE IN H8-H7 LAYER BY LATER THURSDAY MORNING...BUT MOST
OF LAKE EFFECT CONVECTIVE LAYER IS WITHIN DGZ...SO SLR/S AROUND 20:1
WILL BOOST AMOUNTS. POSSIBLE THAT ADVY LEVEL SNOW AMOUNTS COULD
OCCUR LATER WEDNESDAY EVENING THROUGH MID MORNING THURSDAY OVER
MARQUETTE COUNTY...IMPACTING THU MORNING COMMUTE. LATER SHIFTS MAY
NEED TO CONSIDER HEADLINES FOR MARQUETTE COUNTY FOR THIS POTENTIAL.
DRYING SUBSIDENCE BEGINS TO TAKE BITE INTO LK EFFECT OVER WESTERN
CWA ON THURSDAY AFTN. LOCAL WRF PREFERRED WITH LOOK OF LK EFFECT
POPS/QPF THROUGH THURSDAY MORNING AND THIS INDICATES INVERSIONS
LOWERING TO LESS THAN 4KFT BY THURSDAY AFTN IN THE WEST. CURRENT
ENDING TIME OF 12Z THURSDAY FOR THE WEST LOOKING GOOD. SETUP A BIT
BETTER IN EAST THROUGH THURSDAY...BUT EVEN THERE...INVERSIONS LOWER
BLO 5KFT THOUGH THERE IS LINGERING MOISTURE BLO H7 INTO THURSDAY
EVENING. OVERALL...STRONG SUBSIDENCE/DRYING ABOVE INVERSION AND LACK
OF REAL COLD TEMPS WITHIN LK EFFECT MOIST LAYER POINTS TO
SIGNIFICANT DIMINISHING TREND TO LK EFFECT BY LATE THURSDAY
AFTN/EVENING.
EVEN SO...IT IS NOT UNTIL FRIDAY AND MAYBE EVEN AS LATE AS SATURDAY
BEFORE LOW-LEVEL FLOW OVER AREA BECOMES MORE ANTICYCLONIC AS HIGH
PRESSURE OVER NORTHERN CANADA EXPANDS INTO MANITOBA AND NORTHWEST
ONTARIO. NORTH WINDS OFF LK SUPERIOR AND TEMPS AROUND -8C KEEP
CLOUDS AND PERHAPS LGT FLURRIES GOING ON FRIDAY OVR NCNTRL UPR
MICHIGAN. AT SOME POINT...LK EFFECT WILL CEASE DUE TO INCREASING
LOW-LEVEL SHEAR AND SUBSIDENCE WITH CONTINUED WARMING TEMPS AT TOP
OF INVERSION. BY LATER IN THE WEEKEND LAST COUPLE RUNS OF GFS ARE
DEVELOPING WOUND UP SHORTWAVE/LOW PRESSURE SYSTEM IN THE CENTRAL
PLAINS. 12Z/18 MARCH ECMWF WAS MUCH MORE SUPPRESSED WITH SUCH A
SYSTEM RIDING IT ACROSS SOUTHERN TIER OF CONUS. 00Z ECMWF DID SHOW
MORE AMPLIFICATION BUT STILL KEEPS SYSTEM OVER SOUTHERN PORTION OF
OHIO VALLEY. GEM-NH/UKMET MORE WOUND UP NOW TOO...BUT LIKE ECMWF ARE
NOT NEAR AS NORTHWEST AS GFS. CAN NOT COMPLETELY COUNT OUT SOME SORT
OF SYSTEM AS TROUGHING IS PRESENT IN LARGE SCALE FROM WESTERN CANADA
INTO SOUTHERN PLAINS. PREFER THE LOOK OF WPC HAND DRAWN PROGS WITH
LOW TRACKING ACROSS SOUTHEAST CONUS AT THIS POINT. MAIN RESULT IS
QUIET WEATHER OVER UPR LAKES THROUGH THE UPCOMING WEEKEND WITH MORE
CLOUDS THAN SUNSHINE AND HIGH TEMPERATURES AT OR SLIGHTLY BLO NORMAL
IN THE LOW-MID 30S.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z WEDNESDAY MORNING)
ISSUED AT 727 AM EDT TUE MAR 19 2013
AS THE LOW PRES OVER LAKE SUPERIOR DRIFTS E TODAY...STRONG NW WINDS
AND COLDER AIR WILL SPREAD ACROSS THE AREA...BRINGING MDT/HVY LAKE
ENHANCED SNOW/BLSN AND PREVAILING LIFR CONDITIONS TO KIWD/KCMX. DEEPER
MOISTURE WILL SLIP E OF KIWD FOR A TIME THIS AFTN/EVENING...SO THERE
MAY BE PERIOD OF IFR CONDITIONS THERE IN THE AFTN/EVENING. NW WINDS
SHOULD GUST TO 25-35KT AT KIWD AND ESPECIALLY AT THE MORE EXPOSED
KCMX SITE. AT KSAW...DOWNSLOPING WNW WINDS SHOULD RESULT IN MAINLY
MVFR CONDITIONS THRU THE FCST PERIOD.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 547 AM EDT TUE MAR 19 2013
AS LOW PRES OVER ERN LAKE SUPERIOR DRIFTS E TODAY AND TONIGHT...NW
GALES WHICH ARE CURRENTLY DEVELOPING OVER WRN LAKE SUPERIOR WILL
EXPAND E ACROSS THE LAKE TODAY. THE GALES WILL THEN CONTINUE INTO
WED OVER THE E HALF OF THE LAKE WHILE WINDS DIMINISH SLIGHTLY BELOW
GALES OVER THE W. WINDS WILL SLOWLY DIMINISH TO UNDER 25KT FROM W TO
E WED NIGHT/THU. THE COMBINATION OF COLD AIR/STRONG WINDS/HIGH WAVES
WILL LEAD TO PERIODS OF HVY FREEZING SPRAY THRU WED.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
WINTER STORM WARNING UNTIL 8 PM EDT /7 PM CDT/ WEDNESDAY FOR
MIZ001>004-009-084.
WINTER STORM WARNING FROM 11 AM THIS MORNING TO 8 AM EDT
THURSDAY FOR MIZ006-007-085.
LAKE SUPERIOR...
HEAVY FREEZING SPRAY WARNING FROM 2 PM THIS AFTERNOON TO 8 PM
EDT WEDNESDAY FOR LSZ243>245-248>251-264>267.
GALE WARNING UNTIL 2 PM EDT /1 PM CDT/ WEDNESDAY FOR LSZ162-263-
264-266-267.
GALE WARNING FROM 2 PM THIS AFTERNOON TO 2 PM EDT WEDNESDAY FOR
LSZ243>245-249>251-265.
HEAVY FREEZING SPRAY WARNING UNTIL 8 PM EDT /7 PM CDT/ WEDNESDAY
FOR LSZ162-240>242-263.
GALE WARNING FROM 2 PM THIS AFTERNOON TO 6 AM EDT WEDNESDAY FOR
LSZ248.
GALE WARNING FROM 2 PM THIS AFTERNOON TO 11 PM EDT THIS EVENING
FOR LSZ246-247.
GALE WARNING UNTIL 8 PM EDT /7 PM CDT/ THIS EVENING FOR
LSZ240>242.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...ROLFSON
LONG TERM...JLA
AVIATION...ROLFSON
MARINE...ROLFSON
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
550 AM EDT TUE MAR 19 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 547 AM EDT TUE MAR 19 2013
WATER VAPOR IMAGERY AND RUC ANALYSIS SHOW TROF EXTENDING FROM SCNTRL
CANADA INTO THE GREAT LAKES. SNOW IS DIMINISHING ACROSS UPPER MI AS
SHORTWAVE SLIPS E OF THE AREA. AT THE SFC...LOW PRES IS LOCATED OVER
CNTRL LAKE SUPERIOR. ON THE BACKSIDE OF THE LOW...STRONG NW WINDS
ARE DEVELOPING OVER FAR WRN LAKE SUPERIOR AND WILL BE REACHING UPPER
MI SHORTLY.
FCST THINKING HAS NOT CHANGED MUCH SINCE YESTERDAY. STRONG/GUSTY NW
WINDS WILL DEVELOP FROM W TO E TODAY AS SFC LOW PRES DRIFTS E. DEEP
MOISTURE/CONVERGENT CYCLONIC WNW FLOW AND INCREASINGLY COLDER AIR
WILL YIELD MDT/HVY LAKE ENHANCED SNOW DEVELOPING EARLY THIS MORNING
OVER THE W AND SPREADING TO AREAS FROM AROUND MUNISING EASTWARD LATE
MORNING/AFTN. WITH FCST SOUNDINGS SHOWING A DEEP DGZ OVER
GOGEBIC/ONTONAGON COUNTIES...SNOW SHOULD BE VERY HVY AT TIMES IN
THAT AREA TODAY. MEANWHILE...BEST LOW-LEVEL CONVERGENCE WILL SET UP
ACROSS NRN ONTONAGON COUNTY/SRN HALF OF HOUGHTON COUNTY FOR MUCH OF
TODAY/TONIGHT. BOTH FACTORS WILL RESULT IN GREATEST SNOW
ACCUMULATIONS TODAY/TONIGHT OCCURRING FROM THE HIGHER TERRAIN JUST N
OF KIWD TO THE PORCUPINE MOUNTAINS...ROCKLAND...TWIN LAKES AND
PAINESDALE. AMOUNTS UPWARDS OF 18 INCHES FROM 12Z TODAY-12Z WED SEEM
LIKELY IN THOSE AREAS...BUT WOULDN`T BE SURPRISED TO SEE MORE THAN
THAT. FARTHER N ON THE KEWEENAW...AMOUNTS WILL LIKELY TREND DOWN TO
A FOOT OR LESS UNDER WEAKER LOW-LEVEL CONVERGENCE. STRONG BOUNDARY
LAYER WINDS WILL SPREAD STEADIER SNOWS INTO BARAGA COUNTY WITH
ACCUMULATIONS LIKELY REACHING WARNING CRITERIA OVER HIGH TERRAIN. TO
THE E...AIR MASS WON`T BE QUITE AS COLD AND MAY RESULT IN DGZ BEING
DISPLACED A LITTLE ABOVE BEST UPWARD MOTION TODAY...BUT DGZ BECOMES
BETTER POSITIONED IN CONVECTIVE LAYER TONIGHT. LOW-LEVEL CONVERGENCE
IS NOT AS STRONG AS OVER THE W THROUGHOUT TODAY/TONIGHT. THESE
FACTORS SHOULD KEEP SNOW ACCUMULATIONS DOWN TO THE 6-12 INCH RANGE
BY WED MORNING WITH THE GREATEST AMOUNTS E OF MUNISING AND N/NW OF
KERY. WINDS WILL BE A SIGNIFICANT FACTOR. WITH GUSTS OF 30-40MPH...
ALONG LAKE SUPERIOR AND OVER THE KEWEENAW...BLSN WILL BE A MAJOR
ISSUE WITH WHITE-OUTS AT TIMES DUE TO HVY SNOW/BLSN. BLSN WILL BE
MOST SIGNIFICANT OVER THE KEWEENAW PENINSULA...WITH WORST CONDITIONS
THIS AFTN/EVENING.
AWAY FROM HEADLINE AREAS...-SN EARLY WILL TRANSITION TO SCT -SHSN.
DOWNSLOPE WWN WINDS WILL LIKELY BRING AN END TO -SHSN OVER THE
SCNTRL THIS AFTN.
.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 547 AM EDT TUE MAR 19 2013
MODELS ADVERTISE PRETTY STRAIGHT FORWARD LARGE SCALE PATTERN FOR THE
LONG TERM PERIOD. AGREEMENT IN THE PRIMARY FEATURES IN THE LARGER
SCALE FLOW IS GOOD WHICH LEADS TO HIGHER CONFIDENCE FORECAST.
UPPER TROUGH FROM SOUTHERN QUEBEC/NEW ENGLAND WESTWARD ACROSS GREAT
LAKES IS MAIN FEATURE THROUGH LATE THIS WEEK. AS MOST OF UPPER JET
ENERGY ROUNDS BASE OF TROUGH...EXPECT TROUGH TO RAMBLE SLOWLY EAST
BY FRIDAY WHICH RESULTS IN HEIGHTS GRADUALLY RISING OVER UPPER GREAT
LAKES INTO NEXT WEEKEND. SFC PATTERN WELL AGREED UPON AS WELL. SFC
LOW STARTS OUT JUST EAST OF LK SUPERIOR ON WEDNESDAY THEN SHIFTS
INTO SOUTHERN QUEBEC BY THURSDAY WITH TROUGHING ENHANCED BY THE
LAKES LINGERING ACROSS LK SUPERIOR REGION. NO SIGNIFICANT CHANGE
TO PREVIOUS FCST THINKING THAT MODERATE TO AT TIMES HEAVY LK EFFECT
SNOWS IMPACT MAINLY NW SNOW BELTS OF LK SUPERIOR ON WEDNESDAY. DEEP
MOISTURE TIED TO TROUGH LINGERS AND SOUNDINGS ACTUALLY SHOW COLDEST
925-850MB TEMPS THROUGH WEDNESDAY. SFC-H95 CONVERGENCE PEGS HIGHER
TERRAIN OF WESTERN CWA ROUGHLY IRONWOOD-WAKEFIELD THROUGH TWIN LAKES
AND ATLANTIC MINE THOUGH STRONG BLYR WINDS OVER 30 KTS WILL PUSH
HEAVIER SNOW SHOWERS FARTHER INLAND THAN NORMALLY OCCURS WITH SIMILAR
WIND DIRECTION.
CONVERGENCE ALSO STRONG OVER EAST...ROUGHLY MUNISING TO NORTH OF
NEWBERRY. AGAIN STRONG WINDS MAY PUSH AT LEAST MODERATE SNOW SHOWERS
AS FAR SOUTH AS US-2 IN SCHOOLCRAFT COUNTY. HIGHEST SNOW AMOUNTS /UP
TO 6 INCHES IN 12 HRS/ EXPECTED ON WEDNESDAY. SHORTWAVE TROUGH DROPS
THROUGH THE OVERALL MEAN TROUGHING ON WEDNESDAY NIGHT. MODELS HAVE
BEEN SHOWING THIS AWHILE NOW. MAIN RESULT WILL BE WINDS SHIFTING TO
MORE NNW-N DIRECTION VERSUS NW WINDS SEEN THROUGH WEDNESDAY. SNOW
OVER NORTHWEST-WEST MARQUETTE COUNTY COULD AFFECT MORE OF THE COUNTY
WITH MORE NORTHERLY WINDS. SOUNDINGS DO INDICATE DECENT DRYING IN
WAKE OF THE WAVE IN H8-H7 LAYER BY LATER THURSDAY MORNING...BUT MOST
OF LAKE EFFECT CONVECTIVE LAYER IS WITHIN DGZ...SO SLR/S AROUND 20:1
WILL BOOST AMOUNTS. POSSIBLE THAT ADVY LEVEL SNOW AMOUNTS COULD
OCCUR LATER WEDNESDAY EVENING THROUGH MID MORNING THURSDAY OVER
MARQUETTE COUNTY...IMPACTING THU MORNING COMMUTE. LATER SHIFTS MAY
NEED TO CONSIDER HEADLINES FOR MARQUETTE COUNTY FOR THIS POTENTIAL.
DRYING SUBSIDENCE BEGINS TO TAKE BITE INTO LK EFFECT OVER WESTERN
CWA ON THURSDAY AFTN. LOCAL WRF PREFERRED WITH LOOK OF LK EFFECT
POPS/QPF THROUGH THURSDAY MORNING AND THIS INDICATES INVERSIONS
LOWERING TO LESS THAN 4KFT BY THURSDAY AFTN IN THE WEST. CURRENT
ENDING TIME OF 12Z THURSDAY FOR THE WEST LOOKING GOOD. SETUP A BIT
BETTER IN EAST THROUGH THURSDAY...BUT EVEN THERE...INVERSIONS LOWER
BLO 5KFT THOUGH THERE IS LINGERING MOISTURE BLO H7 INTO THURSDAY
EVENING. OVERALL...STRONG SUBSIDENCE/DRYING ABOVE INVERSION AND LACK
OF REAL COLD TEMPS WITHIN LK EFFECT MOIST LAYER POINTS TO
SIGNIFICANT DIMINISHING TREND TO LK EFFECT BY LATE THURSDAY
AFTN/EVENING.
EVEN SO...IT IS NOT UNTIL FRIDAY AND MAYBE EVEN AS LATE AS SATURDAY
BEFORE LOW-LEVEL FLOW OVER AREA BECOMES MORE ANTICYCLONIC AS HIGH
PRESSURE OVER NORTHERN CANADA EXPANDS INTO MANITOBA AND NORTHWEST
ONTARIO. NORTH WINDS OFF LK SUPERIOR AND TEMPS AROUND -8C KEEP
CLOUDS AND PERHAPS LGT FLURRIES GOING ON FRIDAY OVR NCNTRL UPR
MICHIGAN. AT SOME POINT...LK EFFECT WILL CEASE DUE TO INCREASING
LOW-LEVEL SHEAR AND SUBSIDENCE WITH CONTINUED WARMING TEMPS AT TOP
OF INVERSION. BY LATER IN THE WEEKEND LAST COUPLE RUNS OF GFS ARE
DEVELOPING WOUND UP SHORTWAVE/LOW PRESSURE SYSTEM IN THE CENTRAL
PLAINS. 12Z/18 MARCH ECMWF WAS MUCH MORE SUPPRESSED WITH SUCH A
SYSTEM RIDING IT ACROSS SOUTHERN TIER OF CONUS. 00Z ECMWF DID SHOW
MORE AMPLIFICATION BUT STILL KEEPS SYSTEM OVER SOUTHERN PORTION OF
OHIO VALLEY. GEM-NH/UKMET MORE WOUND UP NOW TOO...BUT LIKE ECMWF ARE
NOT NEAR AS NORTHWEST AS GFS. CAN NOT COMPLETELY COUNT OUT SOME SORT
OF SYSTEM AS TROUGHING IS PRESENT IN LARGE SCALE FROM WESTERN CANADA
INTO SOUTHERN PLAINS. PREFER THE LOOK OF WPC HAND DRAWN PROGS WITH
LOW TRACKING ACROSS SOUTHEAST CONUS AT THIS POINT. MAIN RESULT IS
QUIET WEATHER OVER UPR LAKES THROUGH THE UPCOMING WEEKEND WITH MORE
CLOUDS THAN SUNSHINE AND HIGH TEMPERATURES AT OR SLIGHTLY BLO NORMAL
IN THE LOW-MID 30S.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT)
ISSUED AT 138 AM EDT TUE MAR 19 2013
AS THE LOW PRES TROUGH LIFTS TO THE NORTHEAST OF UPPER MI...SNOW
SHOULD DIMINISH FOR A WHILE OVERNIGHT AND MAY ALLOW CONDITIONS TO
IMPROVE TO MVFR...ESPECIALLY AT IWD AND SAW. LATE IN THE NIGHT...
STRONG WNW WINDS AND COLD AIR MOVING IN BEHIND THE LOW WILL BRING
MDT/HVY LAKE ENHANCED SNOW TO IWD/CMX WITH CONDITIONS LIKELY FALLING
TO LIFR. HOWEVER...THE WNW FLOW WILL FAVOR MAINLY MVFR CONDITIONS AT
SAW.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 547 AM EDT TUE MAR 19 2013
AS LOW PRES OVER ERN LAKE SUPERIOR DRIFTS E TODAY AND TONIGHT...NW
GALES WHICH ARE CURRENTLY DEVELOPING OVER WRN LAKE SUPERIOR WILL
EXPAND E ACROSS THE LAKE TODAY. THE GALES WILL THEN CONTINUE INTO
WED OVER THE E HALF OF THE LAKE WHILE WINDS DIMINISH SLIGHTLY BELOW
GALES OVER THE W. WINDS WILL SLOWLY DIMINISH TO UNDER 25KT FROM W TO
E WED NIGHT/THU. THE COMBINATION OF COLD AIR/STRONG WINDS/HIGH WAVES
WILL LEAD TO PERIODS OF HVY FREEZING SPRAY THRU WED.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
WINTER STORM WARNING UNTIL 8 PM EDT /7 PM CDT/ WEDNESDAY FOR
MIZ001>004-009-084.
WINTER STORM WARNING FROM 11 AM THIS MORNING TO 8 AM EDT
THURSDAY FOR MIZ006-007-085.
LAKE SUPERIOR...
HEAVY FREEZING SPRAY WARNING FROM 2 PM THIS AFTERNOON TO 8 PM
EDT WEDNESDAY FOR LSZ243>245-248>251-264>267.
GALE WARNING UNTIL 2 PM EDT /1 PM CDT/ WEDNESDAY FOR LSZ162-263-
264-266-267.
GALE WARNING FROM 2 PM THIS AFTERNOON TO 2 PM EDT WEDNESDAY FOR
LSZ243>245-249>251-265.
HEAVY FREEZING SPRAY WARNING UNTIL 8 PM EDT /7 PM CDT/ WEDNESDAY
FOR LSZ162-240>242-263.
GALE WARNING FROM 2 PM THIS AFTERNOON TO 6 AM EDT WEDNESDAY FOR
LSZ248.
GALE WARNING FROM 2 PM THIS AFTERNOON TO 11 PM EDT THIS EVENING
FOR LSZ246-247.
GALE WARNING UNTIL 8 PM EDT /7 PM CDT/ THIS EVENING FOR
LSZ240>242.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...ROLFSON
LONG TERM...JLA
AVIATION...JLB
MARINE...ROLFSON
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
140 AM EDT TUE MAR 19 2013
.SHORT TERM...(THIS EVENING THROUGH TUESDAY)
ISSUED AT 429 PM EDT MON MAR 18 2013
WATER VAPOR IMAGERY AND RUC ANALYSIS SHOW NEG-TILT TROUGH/VIGOROUS
SHORTWAVE OVER ERN IA/SW WI POISED TO LIFT ENE INTO THE GREAT LAKES
AREA TONIGHT. AREA OF SNOW ASSOC WITH THIS FEATURE STRETCHES FROM
WRN LAKE SUPERIOR/SW UPR MI INTO WI AND NRN LAKE MI. FRONTAL
BOUNDARY OVER THE OHIO/TENNESSEE VALLEYS HAS EFFECTIVELY ROBBED THE
BETTER SURGE OF GULF MOISTURE N TO THE UPPER LAKES AHEAD OF WAVE.
PER 12Z RAOBS...PRECIPITABLE WATER VALUES UPWARDS OF 1 INCH ARE
SOUTH OF THE BOUNDARY WHILE VALUES ARE ONE-QUARTER TO ONE-HALF INCH
OVER THE NRN PLAINS...JUST A LITTLE ABOVE NORMAL FOR THIS TIME OF
YEAR. THE ROBBING OF MOISTURE BY THIS SRN WAVE/FRONT WILL WORK TO
KEEP SNOW ACCUMULATIONS IN CHECK DESPITE VIGOROUS DYNAMICS
ASSOCIATED WITH INCREASINGLY NEG-TILT UPR MS VALLEY SHORTWAVE.
MODEL CONSENSUS PCPN AMOUNTS INTO THIS EVENING ARE ROUGHLY 0.2 TO
0.25 INCHES. WITH SNOW RATIOS LIKELY AROUND 15 TO 1...ADVY FOR
GENERAL SNOWFALL OF 3 TO 4 INCHES STILL LOOKS ON TRACK AS THE SNOW
MAY FALL AT HEAVY AT TIMES FOR A WHILE INTO THE EVENING HRS.
SYNOPTIC SNOW WILL DIMINISH TO PATCHY -SN W TO E TONIGHT AS AREA OF
SNOW TIED TO STRONG FORCING AHEAD OF SHORTWAVE DEPARTS. ATTENTION
LATE TONIGHT THEN TURNS TO THE WRN COUNTIES WHERE STRONG NW WINDS
WILL DEVELOP IN THE WAKE OF SFC LOW MOVING ACROSS ERN LAKE SUPERIOR.
THE STRONG NW WINDS WILL ARRIVE OVER GOGEBIC/ONTONAGON COUNTIES
BEFORE REACHING THE KEWEENAW TUE MORNING. DEEP MOISTURE/CONVERGENT
CYCLONIC WNW FLOW...THE ADVECTION OF INCREASINGLY COLDER 8H TEMPS
ACROSS WRN LAKE SUPERIOR AND A DEEP DGZ SUGGEST VERY HVY LAKE
ENHANCED SNOW WILL LIKELY DEVELOP FROM KIWD N THRU THE KEWEENAW BY
DAYBREAK. COULD EASILY SEE SNOWFALL RATES OF 1-3IN/HR INTO TUESDAY
ACROSS THE HIGHER TERRAIN OF THE W. BLSN WILL ALSO BECOME AN
INCREASING HAZARD AS NW WINDS WILL GUST OVER 30MPH TO AS HIGH AS
40MPH...ESPECIALLY IN OPEN AREAS NEAR LAKE SUPERIOR. WHITE-OUTS WILL
BE A GOOD POSSIBILITY DUE TO COMBINATION OF HVY SNOW/BLSN INTO TUESDAY.
ERN COUNTIES WILL NOT GET INTO THE LAKE ENHANCED SNOW UNTIL WINDS
SHIFT FROM WEST TO NORTHWEST BEHIND COLD FROPA. AS 8H TEMPS SLOWLY
FALL TO AROUND -12 TO -13C OVER ERN LAKE SUPERIOR BY 00Z
WED...EXPECT LAKE ENHANCED SNOW TO GET GOING OVER ERN ALGER...NRN
SCHOOLCRAFT AND LUCE COUNTIES IN CYCLONIC WNW FLOW. ALTHOUGH BEST
MODEL OMEGA INITIALLY MAY STAY BLO DGZ RESULTING IN LOWER SNOW WATER
RATIOS...BELIEVE SNOW ACCUMS WILL INCREASE LATER IN THE DAY ON TUE
AND ESPECIALLY LATE TUE NIGHT AND WED AS COLDER 8H TEMPS CONTINUES TO
SEEP ACROSS ERN LAKE SUPERIOR AND LOW-LVL CONVERGENCE INCREASES WITH
FLOW VEERING NW. NW WINDS INCREASING TO 25-30 MPH...ESPECIALLY ALONG
THE LAKE SUPERIOR SHORE WILL ALSO ADD TO BLOWING SNOW AND LOWER
VSBYS TUE AFTERNOON INTO WEDNESDAY.
AS A RESULT OF CONDITIONS BECOMING INCREASINGLY MORE FAVORABLE FOR
ENHANCED SNOW AND BLOWING SNOW TUE AFTERNOON THROUGH WED
NIGHT...HAVE DECIDED TO UPGRADE WINTER STORM WATCH TO WINTER STORM
WARNING FOR ALGER...LUCE AND NRN SCHOOLCRAFT COUNTIES FOR LATE TUE
MORNING THROUGH WED NIGHT.
.LONG TERM...(TUESDAY NIGHT THROUGH MONDAY)
ISSUED AT 429 PM EDT MON MAR 18 2013
ACTIVE LAKE EFFECT PERIOD FOR NORTHWESTERLY SNOW BELTS WILL CONTINUE
TUESDAY NIGHT INTO EARLY THURSDAY. AS UPPER LOW CLOSES OFF JUST EAST
OF THE AREA AND CYCLONIC FLOW COMBINES WITH H85 TEMPS IN THE -16 TO
-18 RANGE MODERATE TO HEAVY LAKE EFFECT SNOWS WILL CONTINUE. WINDS
WILL CONTINUE TO GUST OVER 35 MPH ESPECIALLY NEAR THE LAKESHORE
THROUGH THE DAY WEDNESDAY INTO WEDNESDAY NIGHT. WILL MAINTAIN THE
LONG DURATION WINTER STORM WARNING ACROSS THE WEST AND KEWEENAW
THROUGH THE DAY WEDNESDAY AND THE EAST INTO THURSDAY MORNING. LAKE
EFFECT SNOW TOTALS IN THE 12 TO 18 INCH RANGE SEEM LIKELY THROUGH
THE TUESDAY TO THURSDAY PERIOD.
LOW LEVEL WINDS BEGIN TO BECOME MORE NORTHERLY ON THURSDAY AS LAKE
EFFECT CONDITIONS BEGIN TO BECOME LESS FAVORABLE. AS MILDER AIR
WRAPS AROUND THE SLOWLY RETROGRADING UPPER LOW EXPECT 85H TEMPS TO
WARM INTO THE -8 TO -10 RANGE AS INVERSION LOWERS. THIS SHOULD
EFFECTIVELY END THE LAKE EFFECT BY LATE THURSDAY INTO EARLY FRIDAY.
OVERALL TREND INTO THE UPCOMING WEEKEND SHOULD FAVOR GENERALLY
TRANQUIL WEATHER WITH TEMPERATURES WITHIN A FEW DEGREES OF NORMAL.
MODELS OFFER SOME MINOR VARIATIONS WITH UPPER LOW DEPARTING THE
AREA AND UPPER PATTERN TRANSITIONING TO A MORE ZONAL FLOW WITH THE
MAIN STORM TRACK SOUTH OF THE AREA...FOR NOW WILL MAINTAIN A
CONSENSUS BLEND.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT)
ISSUED AT 138 AM EDT TUE MAR 19 2013
AS THE LOW PRES TROUGH LIFTS TO THE NORTHEAST OF UPPER MI...SNOW
SHOULD DIMINISH FOR A WHILE OVERNIGHT AND MAY ALLOW CONDITIONS TO
IMPROVE TO MVFR...ESPECIALLY AT IWD AND SAW. LATE IN THE NIGHT...
STRONG WNW WINDS AND COLD AIR MOVING IN BEHIND THE LOW WILL BRING
MDT/HVY LAKE ENHANCED SNOW TO IWD/CMX WITH CONDITIONS LIKELY FALLING
TO LIFR. HOWEVER...THE WNW FLOW WILL FAVOR MAINLY MVFR CONDITIONS AT
SAW.
&&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 429 PM EDT MON MAR 18 2013
TIGHT PRES GRADIENT AHEAD OF THE LOW OVER NW MN WILL CONTINUE SE WINDS
UP TO 30KT TODAY. GALES WILL LIKELY OCCUR TOWARD MID LAKE PORTIONS
OF NCNTRL AND ERN LAKE SUPERIOR...IN PARTICULAR FROM AROUND
WHITEFISH PT NW TOWARD PASSAGE ISLAND. AFTER THE LOW EXITS TO THE
E...NORTHWEST GALES WILL DEVELOP FROM W TO E LATE TONIGHT/TUE. THE
GALES WILL THEN CONTINUE INTO WED OVER THE E HALF OF THE LAKE. WINDS
WILL SLOWLY DIMINISH TO UNDER 25KT FROM W TO E WED NIGHT/THU. THE
COMBINATION OF COLD AIR/STRONG WINDS/HIGH WAVES WILL LEAD TO PERIODS
OF HVY FREEZING SPRAY TUE THRU WED.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
WINTER STORM WARNING UNTIL 8 PM EDT /7 PM CDT/ WEDNESDAY FOR
MIZ001>004-009-084.
WINTER WEATHER ADVISORY UNTIL 5 AM EDT EARLY THIS MORNING FOR
MIZ006-007-014-085.
WINTER STORM WARNING FROM 11 AM THIS MORNING TO 8 AM EDT
THURSDAY FOR MIZ006-007-085.
WINTER WEATHER ADVISORY UNTIL 2 AM EDT /1 AM CDT/ EARLY THIS
MORNING FOR MIZ005-010>013.
LAKE SUPERIOR...
HEAVY FREEZING SPRAY WARNING FROM 2 PM THIS AFTERNOON TO 8 PM
EDT THURSDAY FOR LSZ243>245-248>251-264>267.
GALE WARNING UNTIL 2 PM EDT WEDNESDAY FOR LSZ264-266-267.
GALE WARNING FROM 2 PM THIS AFTERNOON TO 2 PM EDT WEDNESDAY FOR
LSZ243>251-265.
HEAVY FREEZING SPRAY WARNING FROM 5 AM EDT /4 AM CDT/ EARLY THIS
MORNING TO 8 AM EDT /7 AM CDT/ THURSDAY FOR LSZ162-240>242-
263.
GALE WARNING FROM 8 AM EDT /7 AM CDT/ THIS MORNING TO 2 PM EDT
/1 PM CDT/ WEDNESDAY FOR LSZ162-240>242-263.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...VOSS
LONG TERM...MZ
AVIATION...JLB
MARINE...VOSS
AREA FORECAST DISCUSSION
NWS GAYLORD MI
127 AM EDT TUE MAR 19 2013
.SYNOPSIS...
ISSUED AT 352 PM EDT MON MAR 18 2013
AN EXTENDED PERIOD OF LATE SEASON WINTER WEATHER WILL IMPACT
NORTHERN MICHIGAN TONIGHT THROUGH THURSDAY...AS SEVERAL ROUNDS OF
BOTH SYSTEM AND LAKE EFFECT SNOW WORK THROUGH THE REGION. THE FIRST
ROUND OF SNOW WILL CONTINUE INTO TONIGHT...AS LOW PRESSURE TRACKS
THROUGH THE UPPER MIDWEST. AS THAT SYSTEM DEPARTS INTO
ONTARIO...ANOTHER SHOT OF MUCH COLDER AIR WILL ARRIVE LATE TONIGHT
THROUGH THURSDAY...SETTING OFF SEVERAL ROUNDS OF ACCUMULATING LAKE
EFFECT SNOW. SNOW WILL FINALLY END TOWARD FRIDAY AS HIGH PRESSURE
APPROACHES...THOUGH COLD TEMPERATURES WILL REMAIN IN PLACE THROUGH
NEXT WEEKEND.
&&
.UPDATE...
ISSUED AT 1205 AM EDT TUE MAR 19 2013
FORECAST UNFOLDING ABOUT AS EXPECTED...WITH MAIN SYNOPTIC SNOW
SHIELD LIFTING THROUGH NORTHEAST LOWER/EASTERN UPPER AT THIS HOUR.
PRONOUNCED MID LEVEL DRY SLOT IS CURRENTLY OVERTAKING MUCH OF
NORTHEAST LOWER AND WILL CONTINUE TO OVERSPREAD THE ENTIRE CWA THE
NEXT FEW HOURS. LOSS OF MID LEVEL MOISTURE IS NOT HAVING MUCH OF A
BIG IMPACT ON PRECIP...HOWEVER...AS LIGHT SNOW CONTINUES FOR ALL
AREAS...WITH INFLUX OF COLDER AIR ALREADY RUSHING BACK INTO
NORTHWEST LOWER HELPING SET OFF A LAKE ENHANCEMENT RESPONSE. WAS A
LITTLE WORRIED ABOUT FREEZING DRIZZLE EARLIER...ESPECIALLY BENEATH
THE MID LEVEL DRY SLOT...AND WITHIN A WEAK GRADIENT/TROUGH REGION
LIFTING THROUGH THE CWA...BUT HAVE SEEN NO REPORTS AS SUCH TO OUR
SOUTH. THIS IS LIKELY DUE TO THE FACT THAT QUICK SURGE OF COLD
ADVECTION IS MORE THAN SUFFICIENT TO PROVIDE ICE IN THE SATURATED
LAYER...WITH LATEST RAP SOUNDINGS SUGGESTING CLOUD TOP TEMPS IN
THE -13C RANGE. AS SUCH...HAVE REMOVED ANY MENTION THE REMAINDER
OF THE NIGHT.
EXPECT SYNOPTIC SNOW SHIELD WILL LIFT PRIMARILY NORTH OF THE CWA
BY 07Z OR SO...BUT WILL BE REPLACED BY EXPANDING LAKE RESPONSE...
ESPECIALLY FOR NORTHWEST LOWER/EASTERN UPPER. SHOULD BE ABLE TO
GET RID OF HIGHER POPS FOR NORTHEAST LOWER WITH THIS AREA BETTER
REMOVED FROM THE LAKES...BUT STRENGTHENING SHEAR PROFILES SHOULD
ULTIMATELY PROVE SUFFICIENT TO KICK A FEW BANDS OF SNOW BACK INTO
EVEN THOSE AREAS WITH TIME. TEMPS A LITTLE CONVOLUTED WITH ONGOING
LOW LEVEL WARM ADVECTION CONTINUING INTO THE STRAITS/EASTERN U.P.
WHILE COLDER AIR WILL RUSH BACK INTO SOUTHWEST COUNTIES.
UPDATE ISSUED AT 920 PM EDT MON MAR 18 2013
ELONGATED SURFACE LOW CENTER STRETCHES FROM THE ARROWHEAD OF
MINNESOTA THRU WRN UPR MICHIGAN INTO LOWER MICHIGAN LATE THIS
EVENING. WIDESPREAD SNOW IS DIMINISHING TO MORE OF A PATCHY LIGHT
SNOW/FREEZING DRIZZLE REGIME ACROSS OUR SW CWA AS DEEP MOISTURE
PIVOTS NORTHWARD AHEAD OF THE SURFACE LOW CENTER. STILL EXPECT
POPS WILL REMAIN HIGH AS WE HEAD INTO THE OVERNIGHT HOURS DESPITE
A TEMPORARY DIMINISH IN INTENSITY. PATCHY LIGHT SNOW/FREEZING
DRIZZLE WILL RAMP BACK UP TO WIDESPREAD LAKE ENHANCED SNOW SHOWERS
AS COLD AIR WRAPS BACK INTO OUR CWA AS THE SURFACE LOW TRACKS THRU
THE STRAITS AND BEGINS TO DEPART INTO ONTARIO. OVERALL...EXPECT
THE NRN HALF OF OUR CWA AND NW LWR MICHIGAN WILL SEE 2 TO 4 INCHES
OF NEW SNOW THRU THE NIGHT AND 1 TO 2 INCHES FOR OUR SE CWA. WILL
CERTAINLY MAINTAIN THE WINTER WX ADVISORY FOR ERN UPR AND NW LWR
MICHIGAN WERE HIGHEST POPS AND ACCUMULATIONS WILL OCCUR.
UPDATE ISSUED AT 715 PM EDT MON MAR 18 2013
WIDESPREAD SYNOPTICALLY-DRIVEN SNOW CONTINUES TO LIFT NORTHWARD
THRU NRN MICHIGAN THIS EVENING AHEAD OF A POTENT LOW PRESSURE
SYSTEM CENTERED FROM THE ARROWHEAD OF MINNESOTA INTO NRN
WISCONSIN. MANY LOCATIONS ACROSS OUR CWA HAVE PERIODICALLY DROPPED
TO 1/2 MILE IN MODERATE SNOWFALL THIS EVENING. BACK EDGE OF THIS
PRECIP SHIELD HAS REACHED SRN LAKE MICHIGAN AND WILL GRADUALLY
LIFT NORTHWARD TOWARD OUR CWA THROUGHOUT THE EVENING. EXPECT
PRECIP INTENSITY WILL DIMINISH TO LIGHT SNOW/PATCHY FREEZING
DRIZZLE LATER THIS EVENING AS DEPTH OF MOISTURE TEMPORARILY
DIMINISHES AS THE SURFACE LOW SLIDES THRU UPPER MICHIGAN AND THE
STRAITS. SNOW SHOWERS WILL RAMP BACK UP OVERNIGHT AS CAA BEHIND
THE SURFACE LOW ACTIVATES THE LAKES AND WINDS SHIFT AROUND TO THE
WEST. FAR NRN AND NW LWR MICHIGAN WILL BE TARGETED FOR HIGHEST
POPS OVERNIGHT. IN THE MEANTIME...THE HIGHEST SNOW AMOUNTS SHOULD
BE ACROSS ERN UPR MICHIGAN AND THE TIP OF THE MIT THIS EVENING
WHERE SYNOPTIC SNOW WILL FALL FOR THE LONGEST DURATION ALONG AND
JUST NORTH OF THE LOW CENTER. EXPECT 2 TO 4 INCHES OF NEW SNOW FOR
THIS AREA THRU THE NIGHT...TAPERING TO UNDER AN INCH FOR OUR SE
COUNTIES.
&&
.SHORT TERM...(THIS EVENING THROUGH TUESDAY)
ISSUED AT 352 PM EDT MON MAR 18 2013
UPSTREAM SHORT WAVE TROUGH GOING NEGATIVE TILT WITH THE VORTICITY CENTER
NOW PRESSING INTO ILLINOIS. MAIN BATCH OF PRECIP AHEAD OF THE WAVE HAS
BEEN RAMPING UP NICELY ACROSS WISCONSIN INTO LAKE MICHIGAN AND JUST
SKIRTING UP THE NW LOWER MICHIGAN SHORELINE AREAS. PRECIP THINS
OUT CONSIDERABLY EASTWARD ACROSS LOWER MICHIGAN...BUT HAS BEEN
FILLING IN TO SOME DEGREE WITH THE APPROACH OF THE UPSTREAM WAVE
AS IT LIFTS NORTHWARD INTO NRN LOWER MICHIGAN.
TONIGHT...SHORT WAVE TROUGH/VORTICITY CENTER AND ASSOCIATED PRECIP
WILL CONTINUE TO SWING UP INTO NRN MICHIGAN OVER THE NEXT SEVERAL
HOURS. PER RADAR TRENDS...HIGHEST QPF/SNOWFALL LOOKING TO SKIRT UP
THROUGH NW LOWER MICHIGAN INTO EASTERN UPPER MICHIGAN WITH 2 TO 3
INCHES OF ACCUMULATION. LESSER AMOUNTS HEADING EASTWARD ACROSS THE
CWA. PRECIP WILL START TO TAIL OFF SOUTH-NORTH AFTER 03Z OR SO AS
WE LOSE THE FORCING...AND MAY END WITH SOME FZDZ/SNOW MIX AS THE
MID LEVELS DRY OUT A BIT.
OVERNIGHT THROUGH TUESDAY...INITIAL BATCH OF PRECIP LIFTS NORTH
WITH RESPECTABLE COLD ADVECTION SETTING UP OVERNIGHT THROUGH
TUESDAY (CORE OF COLDEST AIR SLIDES THROUGH SRN LOWER MICHIGAN).
VERY GOOD LAKE EFFECT CONDITIONS DEVELOP OVERNIGHT AND PERSIST
THROUGH TUESDAY WITHIN A WSW-WESTERLY FLOW REGIME. THIS WILL LEAD
TO WIDESPREAD LAKE EFFECT SNOW SHOWERS OVER MOST OF NW LOWER
MICHIGAN AND PARTS OF EASTERN UPPER MICHIGAN...ALONG WITH GUSTY
WINDS AND BLOWING SNOW. ONGOING ADVISORY ALREADY IN PLACE TO
ADDRESS THE HAZARD AND PLAN NO CHANGES AT THIS POINT.
&&
.LONG TERM...(TUESDAY NIGHT THROUGH MONDAY)
ISSUED AT 352 PM EDT MON MAR 18 2013
A PROLONGED STRETCH OF LAKE EFFECT SNOW FOR NORTHERN MICHIGAN...WITH
LITTLE SIGN OF SPRING /DESPITE WHAT THE CALENDAR SAYS/. MAIN
FORECAST ISSUES ARE SNOWFALL TOTALS AND HEADLINE MANAGEMENT.
TUESDAY NIGHT THROUGH THURSDAY...GROWING CONFIDENCE IN AN IMPRESSIVE
LATE SEASON LAKE EFFECT SNOW EVENT FOR PORTIONS OF NORTHERN
MICHIGAN. UPPER LOW WILL CLOSE OFF OVER THE NORTHERN LAKES AND
REMAIN IN THIS AREA THRU THURSDAY. A SERIES OF SFC TROFS/SHORTWAVES
WITH DEEPER POCKETS OF MOISTURE WILL ROTATE AROUND THE UPPER
LOW...ENHANCING THE SNOWFALL FROM TIME TO TIME. LOW LEVEL FLOW
FAIRLY STEADY IN THE WNW/NW RANGE THROUGHOUT...WITH EXCELLENT
CYCLONIC CURVATURE RESULTING IN A LAKE SUPERIOR CONNECTION.
FORECAST SOUNDINGS ALSO IMPRESSIVE...WITH DEEP MOISTURE AND OMEGA
THRU THE DGZ AND NEAR NON-EXISTENT INVERSIONS. LESS BULK SHEAR
PRESENT WEDNESDAY/THURSDAY AFTERNOONS...WHICH WILL SUPPORT MORE
DIURNAL DISRUPTION OF BANDING STRUCTURES BUT ALSO WILL LIKELY LEAD
TO MORE "SPREAD OUT" SNOW SHOWER ACTIVITY OUTSIDE OF THE PREFERRED LES
AREAS. ALL IN ALL...CURRENT FORECAST HAS THIS HANDLED WELL WITH AN
EXTENDED PERIOD OF CATEGORICAL POPS IN W/NW FLOW AREAS BUT AN
EXPANSION OF LIKELY POPS FOR THE AFTN HOURS WITH AFOREMENTIONED
DIURNAL DISRUPTION. PLENTY OF MESOSCALE DETAILS THAT WILL HAVE TO
BE WORKED OUT WITH REGARD TO THIS EVENT...AND THOSE ARE PROBABLY
BEST HANDLED IN THE SHORT TERM.
SO HOW MUCH SNOW WILL FALL? CIPS ANALOGS AND SIMILAR SOUNDINGS
WOULD POINT TOWARD SOME BEEFY TOTALS IN EXCESS OF A FOOT IN SOME
AREAS THRU THURSDAY. MY MAIN CONCERN IS HOW THE HIGH MARCH SUN
ANGLE MAY REALLY CUT DOWN SNOW ACCUM/S DURING THE DAYLIGHT HOURS
WITH JUST WET ROADS...WITH MOST OF THE ACCUM/S OCCURRING AT NIGHT
INTO THE EARLY MORNING HOURS. I WILL MAKE A FEW ADJUSTMENTS IN THE
CURRENT FORECAST TO TREND IT IN THIS DIRECTION WHICH WILL LIKELY
BRING DOWN STORM TOTAL SNOWFALL AMOUNTS JUST A BIT. OVERALL...
CURRENT IDEA OF A PROLONGED WINTER WEATHER ADVISORY FOR LES FAVORED
AREAS LOOKS GOOD. COULD CERTAINLY DEBATE THE TYPE OF HEADLINE /LAKE
EFFECT SNOW VERSUS WINTER WEATHER/...BUT GIVEN THE GUSTY WINDS ON
THE FRONT END OF THE EVENT AT 25 MPH...MORE GENERIC WINTER WEATHER
ADVISORY APPEARS WARRANTED. WILL ALSO LIKELY SEE SOME TIME FRAMES
OVER THIS SEVERAL DAY PERIOD WHERE HEADLINES MAY NOT BE NEEDED...BUT
TO AVOID LOTS OF HEADLINE CHANGES FROM DAY TO DAY...SIMPLER LONG
DURATION SINGLE HEADLINE LIKELY CREATES THE LEAST CONFUSION.
THURSDAY NIGHT THROUGH SUNDAY...FLOW TURNS MORE NNW THURSDAY NIGHT
WITH AIR MASS MODIFICATION WARMING WRAPPING AROUND NRN PERIPHERY OF
THE UPPER LOW THAT GRADUALLY RELEASES TO THE NE CONUS. WE REMAIN IN
BROAD TROUGHING WITH WEAK WAVES ROTATING THROUGH THE GREAT
LAKES...WITH NO REALLY GOOD CHANCE FOR SNOW. IT/S A RATHER DINGY
LOOKING AIR MASS WITH SOME AFTERNOON CUMULUS AND POSSIBLY SOME
OVERNIGHT LAKE STRATUS/FLURRIES?? WILL KEEP FORECAST PRECIP FREE FOR
NOW...WITH STRONGER MARCH SUN BRINGING TEMPERATURES BACK INTO THE
30S /WHICH IS STILL A FEW DEGREES BELOW NORMAL/.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT)
ISSUED AT 127 AM EDT TUE MAR 19 2013
INCREASINGLY GUSTY WEST WINDS AND PERIODS OF SNOW WILL BE THE MAIN
STORY FOR THE TERMINAL SITES THE NEXT 24 HOURS...ALL AS COLDER AIR
POURS INTO THE AREA. THE PLN/TVC AND TO A SOMEWHAT LESSER DEGREE
MBL TERMINALS WILL BE IMPACTED BY THE MOST PERSISTENT ACTIVITY...
WITH CONDITIONS SLIDING FROM MVFR EARLY THIS MORNING TOWARD IFR
THROUGH THE DAY AS LAKE EFFECT SNOW INCREASES IN INTENSITY. HAVE
SHOWN STEADY STATE IFR VISIBILITIES IN THE TAF FORECAST FOR THE
DAYLIGHT HOURS...BUT WILL NO DOUBT SEE SOME FLUCTUATIONS...WITH
PERIODS OF LIFR POSSIBLE IN HEAVIER SNOW SHOWERS. THAT SNOW WILL
WIND DOWN IN INTENSITY AND COVERAGE THROUGH THE EVENING HOURS...
BUT WITH MVFR VISBYS AND/OR CEILINGS PREVAILING. WINDS WILL BE
QUITE GUSTY AT ALL SITES THROUGH THE PERIOD FROM THE WEST/
SOUTHWEST INITIALLY...BECOMING WEST/NORTHWEST WITH TIME. GUSTS
UP TO 30 KNOTS ARE EXPECTED.
&&
.MARINE...
ISSUED AT 1205 AM EDT TUE MAR 19 2013
UPDATE: HAVE RE-ISSUED SMALL CRAFT ADVISORIES FOR ALL WATERS
(MINUS THOSE NEAR MANISTEE HARBOR WHERE GALES ARE IN EFFECT LATER
TONIGHT). EASTERLY FLOW INTO THE STRAITS/WHITEFISH BAY WILL
SLACKEN OVER THE NEXT FEW HOURS...WITH STRONGER WESTERLY WINDS
DEVELOPING FOR ALL AREAS NO LATER THAN SUNRISE. THOSE WINDS WILL
REMAIN GUSTY RIGHT ON THROUGH TONIGHT...AND WILL LIKELY HAVE TO
EVENTUALLY EXTEND THE NEWLY ISSUED HEADLINES.
PREVIOUS DISCUSSION:
GUSTY EAST TO SOUTHEAST WINDS WILL BE FOUND ACROSS ALL THE
NEARSHORE WATERS THROUGH THE EARLY EVENING HOURS...AS LOW PRESSURE
TRACKS THROUGH THE UPPER MIDWEST. SMALL CRAFT ADVISORIES WILL
CONTINUE ACROSS A GOOD CHUNK OF THE WATERS...BUT CHANNELING OF
EASTERLY FLOW WILL REQUIRE GALE WARNINGS FOR NORTHERN LAKE
HURON/LAKE MICHIGAN AND THE STRAITS...AS WELL AS WHITEFISH BAY.
WINDS WILL TEND TO DIMINISH FOR A TIME FROM SOUTH TO NORTH AS A
FRONTAL BOUNDARY LIFTS THROUGH THIS EVENING. HOWEVER...THAT LULL
WILL BE SHORT LIVED AS ANOTHER ROUND OF MUCH COLDER AIR RUSHES
BACK ACROSS THE WATERS LATER TONIGHT. SHOULD SEE AT LEAST
WIDESPREAD SMALL CRAFT ADVISORY CONDITIONS RE- DEVELOP FOR ALL
WATERS INTO TUESDAY...WITH GALE GUSTS ACROSS MAINLY SOUTHERN LAKE
MICHIGAN IMPACTING THE WATERS CLOSER TO MANISTEE. COLD CONDITIONS
AND GUSTY WINDS WILL THEN PREVAIL RIGHT ON THROUGH WEDNESDAY
NIGHT...WITH ADDITIONAL SMALL CRAFT ADVISORIES EXPECTED.
&&
.APX WATCHES/WARNINGS/ADVISORIES...
MI...WINTER WEATHER ADVISORY UNTIL 8 PM EDT THURSDAY FOR MIZ008-
019>022-026>028.
WINTER WEATHER ADVISORY UNTIL 2 AM EDT WEDNESDAY FOR MIZ015>017-
025-031-032.
LH...SMALL CRAFT ADVISORY UNTIL 8 AM EDT WEDNESDAY FOR LHZ345-347>349.
LM...SMALL CRAFT ADVISORY UNTIL 8 AM EDT WEDNESDAY FOR LMZ323-341-342-
344.
GALE WARNING UNTIL 5 PM EDT THIS AFTERNOON FOR LMZ345-346.
LS...SMALL CRAFT ADVISORY UNTIL 8 AM EDT WEDNESDAY FOR LSZ321.
&&
$$
UPDATE...LAWRENCE
SYNOPSIS...NS
SHORT TERM...BA
LONG TERM...JK
AVIATION...LAWRENCE
MARINE...BA/LAWRENCE
AREA FORECAST DISCUSSION
NWS BILLINGS MT
1135 AM MDT TUE MAR 19 2013
.SHORT TERM...VALID FOR TDY AND WED...
HAVE UPDATED YET AGAIN TO CARRY SCATTERED COVERAGE FOR SNOW
SHOWERS TIL 21Z. ACTIVITY IS SHALLOW WITH TOPS AROUND -20C... BUT
DENDRITIC LAYER IS MOIST AND UNSTABLE AT LOW LEVELS...THUS THE
SNOW SHOWERS CONTINUE WITHIN BLYR CONVERGENT REGION. SUBSIDENCE
SEEN WORKING INTO CENTRAL MT NOW...SO DIMINISHING TREND WILL BEGIN
OVER THE NEXT 1-2 HOURS. JKL
PREVIOUS DISCUSSION...
WEAK SHORTWAVE EMBEDDED IN AN UNSTABLE NW FLOW COMBINED WITH LOW
LEVEL FRONTOGENESIS ALONG SFC BOUNDARY AND TEMPERATURES FAVORABLE
FOR DENDRITIC GROWTH ARE ALLOWING FOR LIGHT SNOW SHOWERS/FLURRIES
TO CONTINUE IN AN AREA FROM JUDITH GAP...ROUNDUP AND BILLINGS
EAST/SOUTHWARD TO FORSYTH AND SHERIDAN. OBS/WEB CAMS SHOW JUST A
DUSTING TO LESS THAN A HALF INCH FOR MOST OF THIS AREA. CLOUD TOPS
NOT WARMING YET BUT THEY WILL SHORTLY AS SHORTWAVE ENERGY DEPARTS
AND FRONTOGENESIS WEAKENS...PER RAP WHICH SEEMS TO HAVE A FAIR
HANDLING OF THE CURRENT SITUATION. HAVE EXPANDED SCATTERED
COVERAGE FOR THIS ACTIVITY... WHICH WILL PROBABLY PERSIST TO A
COUPLE HOURS BEYOND 18Z INTO THE AFTERNOON...BUT OTHERWISE A
DIMINISHING TREND IS ANTICIPATED THIS AFTERNOON AS HEIGHTS BEGIN
TO RISE FROM THE WEST. DOWNSLOPE WINDS AND SUN WILL ALLOW FOR
TEMPS INTO THE 40S OUT WEST...BUT LOW LEVEL NORTH TO EAST WINDS
AND POOR MIXING WILL KEEP TEMPS IN THE 30S CENTRAL AND EAST
PARTS...AND EVEN MID TO UPPER 20S ALONG THE DAKOTAS BORDER WHERE
COLD AIR ASSOCIATED WITH CANADIAN SFC RIDGE WILL BE DEEPEST.
AS FOR BILLINGS...LIGHT SNOW SHOWERS/FLURRIES WILL TAPER OFF BY
NOON BUT LIGHT TO EAST WINDS WILL KEEP TEMPS ON THE COOLISH SIDE
TODAY WITH HIGHS IN THE UPPER 30S TO NEAR 40...IE ABOUT 10
DEGREES BELOW NORMAL.
LOOK FOR A DRY NIGHT TONIGHT AS UPPER RIDGE BUILDS OVER THE
REGION. THIS WILL LEAD TO A WARMER WEDNESDAY PRIOR TO WED NITE/THU
SHORTWAVE/COLD FRONT.
JKL
.LONG TERM...VALID FOR THU...FRI...SAT...SUN...MON...
MEDIUM AND LONG RANGE MODELS REMAIN IN GOOD AGREEMENT. ALL MODELS
CONTINUE TO ADVERTISE UNSETTLED WEATHER TREND FOR THURSDAY THROUGH
EARLY NEXT WEEK ALONG WITH BELOW NORMAL TEMPERATURES.
MAIN WEATHER PRODUCER WILL BE ON THURSDAY AS AN UPPER LEVEL TROUGH
OF LOW PRESSURE MOVES IN FROM THE PACIFIC NORTHWEST. LEFT EXIT
REGION OF THE JET ASSOCIATED WITH THIS TROUGH WILL BE MOVING OVER
OUR AREA ALONG WITH MODERATE QG FORCING. GOOD PACIFIC MOISTURE
FEED INDICATED BY MODELS AND THIS WILL COMBINE WITH AN INVERTED
SURFACE TROUGH TO BRING SNOW TO OUR SOUTHWEST MOUNTAINS AND AREAS
WEST OF BILLINGS THURSDAY MORNING. THIS FORCING WITH THE UPPER
TROUGH WILL SHIFT EASTWARD THROUGH THE DAY. HAVE RAISED POPS IN
THE WEST FOR THURSDAY MORNING AND ALSO ALONG THE FOOTHILLS FROM
RED LODGE TO MC LEOD AS A SHORT PERIOD OF UPSLOPE FLOW WILL TAKE
PLACE WITH THE PASSAGE OF A COLD FRONT MOVING IN FROM THE NORTH.
ALSO INCREASED POPS TO LIKELY IN OUR EASTERN ZONES WITH INVERTED
SURFACE TROUGH MOVING OVER THIS AREA.
FRIDAY INTO EARLY NEXT WEEK WILL REMAIN UNSETTLED AS A BROAD
UPPER LEVEL TROUGH WILL REAMIN OVER THE NORTHERN PLAINS. MAIN LIFT
WITH THE TROUGH WILL STAY NORTH OF OUR AREA BUT ENOUGH ENERGY FROM
WEAK IMPULSES MOVING THROUGH TO BRING SCATTERED RAIN OR SNOW
SHOWERS. TEMPERATURES WILL BE BLOW SEASONAL NORMALS AS COLDER
CANADIAN AIR WILL FILTER INTO OUR AREA. HIGH TEMPERATURES WILL BE
IN THE UPPER 30S TO LOWER 40S. DID LOWER OVERNIGHT TEMPERATURES
WITH MODELS ADVECTING COLDER AIR INTO SOUTHERN MONTANA DURING
THIS TIME PERIOD. RICHMOND
&&
.AVIATION...
ISOLATED TO SCATTERED SNOW SHOWERS CONTINUE TO IMPACT WESTERN
ROUTES...INCLUDING KBIL AND KSHR...AS WELL AS HIGH TERRAIN.
LOCALIZED REDUCED FLIGHT CONDITIONS...AS LOW AS IFR AND LIFR CIGS
AND VIS AT TIMES. MOUNTAIN OBSCURATIONS CAN BE EXPECTED THIS
MORNING WITH THE SNOW SHOWERS. PRECIPITATION SHOULD BEGIN TO CLEAR
FROM WEST TO EAST BY LATE MORNING...WITH MAINLY VFR CONDITIONS
PREVAILING THROUGH THE REMAINDER OF THE DAY. AAG
&&
.PRELIMINARY POINT TEMP/POPS...
TDY WED THU FRI SAT SUN MON
-------------------------------------------------------
BIL 038 026/056 032/042 027/038 022/041 023/040 025/039
3/J 01/E 45/W 32/W 21/B 12/J 22/W
LVM 042 026/054 034/042 024/038 019/036 019/038 020/038
0/B 02/W 56/W 32/J 22/J 22/J 22/J
HDN 037 023/056 029/043 026/039 023/040 022/041 025/040
3/J 01/B 46/W 42/W 21/B 12/W 21/B
MLS 031 021/046 026/038 024/037 022/039 020/040 022/041
1/B 01/B 26/W 42/J 11/B 11/B 11/B
4BQ 033 020/047 024/039 023/036 021/037 020/039 020/040
2/J 00/B 16/W 42/J 11/B 12/W 21/B
BHK 025 014/037 019/031 019/033 017/033 016/034 017/035
1/B 00/N 16/J 43/J 11/B 11/B 11/E
SHR 034 018/052 027/039 021/034 018/036 017/036 018/034
4/J 01/B 26/W 43/J 22/J 23/J 21/B
&&
.BYZ WATCHES/WARNINGS/ADVISORIES...
MT...NONE.
WY...NONE.
&&
$$
WEATHER.GOV/BILLINGS
AREA FORECAST DISCUSSION
NWS BILLINGS MT
1018 AM MDT TUE MAR 19 2013
.SHORT TERM...VALID FOR TDY AND WED...
HAVE UPDATED AGAIN TO EXTEND ISOLATED POPS FOR LIGHT SNOW SHOWERS
TIL 21Z IN OUR SOUTH CENTRAL PARTS. LOCALIZED HALF INCH ACCUMS
EXPECTED IN HEAVIER SNOW BANDS. OTHERWISE NO CHANGES. JKL
PREVIOUS DISCUSSION ISSUED 905 AM...
WEAK SHORTWAVE EMBEDDED IN AN UNSTABLE NW FLOW COMBINED WITH LOW
LEVEL FRONTOGENESIS ALONG SFC BOUNDARY AND TEMPERATURES FAVORABLE
FOR DENDRITIC GROWTH ARE ALLOWING FOR LIGHT SNOW SHOWERS/FLURRIES
TO CONTINUE IN AN AREA FROM JUDITH GAP...ROUNDUP AND BILLINGS
EAST/SOUTHWARD TO FORSYTH AND SHERIDAN. OBS/WEB CAMS SHOW JUST A
DUSTING TO LESS THAN A HALF INCH FOR MOST OF THIS AREA. CLOUD TOPS
NOT WARMING YET BUT THEY WILL SHORTLY AS SHORTWAVE ENERGY DEPARTS
AND FRONTOGENESIS WEAKENS...PER RAP WHICH SEEMS TO HAVE A FAIR
HANDLING OF THE CURRENT SITUATION. HAVE EXPANDED SCATTERED
COVERAGE FOR THIS ACTIVITY... WHICH WILL PROBABLY PERSIST TO A
COUPLE HOURS BEYOND 18Z INTO THE AFTERNOON...BUT OTHERWISE A
DIMINISHING TREND IS ANTICIPATED THIS AFTERNOON AS HEIGHTS BEGIN
TO RISE FROM THE WEST. DOWNSLOPE WINDS AND SUN WILL ALLOW FOR
TEMPS INTO THE 40S OUT WEST...BUT LOW LEVEL NORTH TO EAST WINDS
AND POOR MIXING WILL KEEP TEMPS IN THE 30S CENTRAL AND EAST
PARTS...AND EVEN MID TO UPPER 20S ALONG THE DAKOTAS BORDER WHERE
COLD AIR ASSOCIATED WITH CANADIAN SFC RIDGE WILL BE DEEPEST.
AS FOR BILLINGS...LIGHT SNOW SHOWERS/FLURRIES WILL TAPER OFF BY
NOON BUT LIGHT TO EAST WINDS WILL KEEP TEMPS ON THE COOLISH SIDE
TODAY WITH HIGHS IN THE UPPER 30S TO NEAR 40...IE ABOUT 10
DEGREES BELOW NORMAL.
LOOK FOR A DRY NIGHT TONIGHT AS UPPER RIDGE BUILDS OVER THE
REGION. THIS WILL LEAD TO A WARMER WEDNESDAY PRIOR TO WED NITE/THU
SHORTWAVE/COLD FRONT.
JKL
.LONG TERM...VALID FOR THU...FRI...SAT...SUN...MON...
MEDIUM AND LONG RANGE MODELS REMAIN IN GOOD AGREEMENT. ALL MODELS
CONTINUE TO ADVERTISE UNSETTLED WEATHER TREND FOR THURSDAY THROUGH
EARLY NEXT WEEK ALONG WITH BELOW NORMAL TEMPERATURES.
MAIN WEATHER PRODUCER WILL BE ON THURSDAY AS AN UPPER LEVEL TROUGH
OF LOW PRESSURE MOVES IN FROM THE PACIFIC NORTHWEST. LEFT EXIT
REGION OF THE JET ASSOCIATED WITH THIS TROUGH WILL BE MOVING OVER
OUR AREA ALONG WITH MODERATE QG FORCING. GOOD PACIFIC MOISTURE
FEED INDICATED BY MODELS AND THIS WILL COMBINE WITH AN INVERTED
SURFACE TROUGH TO BRING SNOW TO OUR SOUTHWEST MOUNTAINS AND AREAS
WEST OF BILLINGS THURSDAY MORNING. THIS FORCING WITH THE UPPER
TROUGH WILL SHIFT EASTWARD THROUGH THE DAY. HAVE RAISED POPS IN
THE WEST FOR THURSDAY MORNING AND ALSO ALONG THE FOOTHILLS FROM
RED LODGE TO MC LEOD AS A SHORT PERIOD OF UPSLOPE FLOW WILL TAKE
PLACE WITH THE PASSAGE OF A COLD FRONT MOVING IN FROM THE NORTH.
ALSO INCREASED POPS TO LIKELY IN OUR EASTERN ZONES WITH INVERTED
SURFACE TROUGH MOVING OVER THIS AREA.
FRIDAY INTO EARLY NEXT WEEK WILL REMAIN UNSETTLED AS A BROAD
UPPER LEVEL TROUGH WILL REAMIN OVER THE NORTHERN PLAINS. MAIN LIFT
WITH THE TROUGH WILL STAY NORTH OF OUR AREA BUT ENOUGH ENERGY FROM
WEAK IMPULSES MOVING THROUGH TO BRING SCATTERED RAIN OR SNOW
SHOWERS. TEMPERATURES WILL BE BLOW SEASONAL NORMALS AS COLDER
CANADIAN AIR WILL FILTER INTO OUR AREA. HIGH TEMPERATURES WILL BE
IN THE UPPER 30S TO LOWER 40S. DID LOWER OVERNIGHT TEMPERATURES
WITH MODELS ADVECTING COLDER AIR INTO SOUTHERN MONTANA DURING
THIS TIME PERIOD. RICHMOND
&&
.AVIATION...
ISOLATED TO SCATTERED SNOW SHOWERS CONTINUE TO IMPACT WESTERN
ROUTES...INCLUDING KBIL AND KSHR...AS WELL AS HIGH TERRAIN.
LOCALIZED REDUCED FLIGHT CONDITIONS...AS LOW AS IFR AND LIFR CIGS
AND VIS AT TIMES. MOUNTAIN OBSCURATIONS CAN BE EXPECTED THIS
MORNING WITH THE SNOW SHOWERS. PRECIPITATION SHOULD BEGIN TO CLEAR
FROM WEST TO EAST BY LATE MORNING...WITH MAINLY VFR CONDITIONS
PREVAILING THROUGH THE REMAINDER OF THE DAY. AAG
&&
.PRELIMINARY POINT TEMP/POPS...
TDY WED THU FRI SAT SUN MON
-------------------------------------------------------
BIL 038 026/056 032/042 027/038 022/041 023/040 025/039
2/J 01/E 45/W 32/W 21/B 12/J 22/W
LVM 042 026/054 034/042 024/038 019/036 019/038 020/038
0/B 02/W 56/W 32/J 22/J 22/J 22/J
HDN 037 023/056 029/043 026/039 023/040 022/041 025/040
3/J 01/B 46/W 42/W 21/B 12/W 21/B
MLS 031 021/046 026/038 024/037 022/039 020/040 022/041
1/B 01/B 26/W 42/J 11/B 11/B 11/B
4BQ 033 020/047 024/039 023/036 021/037 020/039 020/040
2/J 00/B 16/W 42/J 11/B 12/W 21/B
BHK 025 014/037 019/031 019/033 017/033 016/034 017/035
1/B 00/N 16/J 43/J 11/B 11/B 11/E
SHR 034 018/052 027/039 021/034 018/036 017/036 018/034
4/J 01/B 26/W 43/J 22/J 23/J 21/B
&&
.BYZ WATCHES/WARNINGS/ADVISORIES...
MT...NONE.
WY...NONE.
&&
$$
WEATHER.GOV/BILLINGS
AREA FORECAST DISCUSSION
NWS BILLINGS MT
905 AM MDT TUE MAR 19 2013
.SHORT TERM...VALID FOR TDY AND WED...
WEAK SHORTWAVE EMBEDDED IN AN UNSTABLE NW FLOW COMBINED WITH LOW
LEVEL FRONTOGENESIS ALONG SFC BOUNDARY AND TEMPERATURES FAVORABLE
FOR DENDRITIC GROWTH ARE ALLOWING FOR LIGHT SNOW SHOWERS/FLURRIES
TO CONTINUE IN AN AREA FROM JUDITH GAP...ROUNDUP AND BILLINGS
EAST/SOUTHWARD TO FORSYTH AND SHERIDAN. OBS/WEB CAMS SHOW JUST A
DUSTING TO LESS THAN A HALF INCH FOR MOST OF THIS AREA. CLOUD TOPS
NOT WARMING YET BUT THEY WILL SHORTLY AS SHORTWAVE ENERGY DEPARTS
AND FRONTOGENESIS WANES...PER RAP WHICH SEEMS TO HAVE A FAIR
HANDLING OF THE CURRENT SITUATION. HAVE EXPANDED SCATTERED
COVERAGE FOR THIS ACTIVITY... WHICH WILL PROBABLY PERSIST TO A
COUPLE HOURS BEYOND 18Z INTO THE AFTERNOON...BUT OTHERWISE A
DIMINISHING TREND IS ANTICIPATED THIS AFTERNOON AS HEIGHTS BEGIN
TO RISE FROM THE WEST. DOWNSLOPE WINDS AND SUN WILL ALLOW FOR
TEMPS INTO THE 40S OUT WEST...BUT LOW LEVEL NORTH TO EAST WINDS
AND POOR MIXING WILL KEEP TEMPS IN THE 30S CENTRAL AND EAST
PARTS...AND EVEN MID TO UPPER 20S ALONG THE DAKOTAS BORDER WHERE
COLD AIR ASSOCIATED WITH CANADIAN SFC RIDGE WILL BE DEEPEST.
AS FOR BILLINGS...LIGHT SNOW SHOWERS/FLURRIES WILL TAPER OFF BY
NOON BUT LIGHT TO EAST WINDS WILL KEEP TEMPS ON THE COOLISH SIDE
TODAY WITH HIGHS IN THE UPPER 30S TO NEAR 40...IE ABOUT 10
DEGREES BELOW NORMAL.
LOOK FOR A DRY NIGHT TONIGHT AS UPPER RIDGE BUILDS OVER THE
REGION. THIS WILL LEAD TO A WARMER WEDNESDAY PRIOR TO WED NITE/THU
SHORTWAVE/COLD FRONT.
JKL
.LONG TERM...VALID FOR THU...FRI...SAT...SUN...MON...
MEDIUM AND LONG RANGE MODELS REMAIN IN GOOD AGREEMENT. ALL MODELS
CONTINUE TO ADVERTISE UNSETTLED WEATHER TREND FOR THURSDAY THROUGH
EARLY NEXT WEEK ALONG WITH BELOW NORMAL TEMPERATURES.
MAIN WEATHER PRODUCER WILL BE ON THURSDAY AS AN UPPER LEVEL TROUGH
OF LOW PRESSURE MOVES IN FROM THE PACIFIC NORTHWEST. LEFT EXIT
REGION OF THE JET ASSOCIATED WITH THIS TROUGH WILL BE MOVING OVER
OUR AREA ALONG WITH MODERATE QG FORCING. GOOD PACIFIC MOISTURE
FEED INDICATED BY MODELS AND THIS WILL COMBINE WITH AN INVERTED
SURFACE TROUGH TO BRING SNOW TO OUR SOUTHWEST MOUNTAINS AND AREAS
WEST OF BILLINGS THURSDAY MORNING. THIS FORCING WITH THE UPPER
TROUGH WILL SHIFT EASTWARD THROUGH THE DAY. HAVE RAISED POPS IN
THE WEST FOR THURSDAY MORNING AND ALSO ALONG THE FOOTHILLS FROM
RED LODGE TO MC LEOD AS A SHORT PERIOD OF UPSLOPE FLOW WILL TAKE
PLACE WITH THE PASSAGE OF A COLD FRONT MOVING IN FROM THE NORTH.
ALSO INCREASED POPS TO LIKELY IN OUR EASTERN ZONES WITH INVERTED
SURFACE TROUGH MOVING OVER THIS AREA.
FRIDAY INTO EARLY NEXT WEEK WILL REMAIN UNSETTLED AS A BROAD
UPPER LEVEL TROUGH WILL REAMIN OVER THE NORTHERN PLAINS. MAIN LIFT
WITH THE TROUGH WILL STAY NORTH OF OUR AREA BUT ENOUGH ENERGY FROM
WEAK IMPULSES MOVING THROUGH TO BRING SCATTERED RAIN OR SNOW
SHOWERS. TEMPERATURES WILL BE BLOW SEASONAL NORMALS AS COLDER
CANADIAN AIR WILL FILTER INTO OUR AREA. HIGH TEMPERATURES WILL BE
IN THE UPPER 30S TO LOWER 40S. DID LOWER OVERNIGHT TEMPERATURES
WITH MODELS ADVECTING COLDER AIR INTO SOUTHERN MONTANA DURING
THIS TIME PERIOD. RICHMOND
&&
.AVIATION...
ISOLATED TO SCATTERED SNOW SHOWERS CONTINUE TO IMPACT WESTERN
ROUTES...INCLUDING KBIL AND KSHR...AS WELL AS HIGH TERRAIN.
LOCALIZED REDUCED FLIGHT CONDITIONS...AS LOW AS IFR AND LIFR CIGS
AND VIS AT TIMES. MOUNTAIN OBSCURATIONS CAN BE EXPECTED THIS
MORNING WITH THE SNOW SHOWERS. PRECIPITATION SHOULD BEGIN TO CLEAR
FROM WEST TO EAST BY LATE MORNING...WITH MAINLY VFR CONDITIONS
PREVAILING THROUGH THE REMAINDER OF THE DAY. AAG
&&
.PRELIMINARY POINT TEMP/POPS...
TDY WED THU FRI SAT SUN MON
-------------------------------------------------------
BIL 039 026/056 032/042 027/038 022/041 023/040 025/039
2/J 01/E 45/W 32/W 21/B 12/J 22/W
LVM 042 026/054 034/042 024/038 019/036 019/038 020/038
0/B 12/W 56/W 32/J 22/J 22/J 22/J
HDN 037 023/056 029/043 026/039 023/040 022/041 025/040
3/J 01/B 46/W 42/W 21/B 12/W 21/B
MLS 031 021/046 026/038 024/037 022/039 020/040 022/041
1/B 01/B 26/W 42/J 11/B 11/B 11/B
4BQ 033 020/047 024/039 023/036 021/037 020/039 020/040
2/J 00/B 16/W 42/J 11/B 12/W 21/B
BHK 025 014/037 019/031 019/033 017/033 016/034 017/035
1/B 00/N 16/J 43/J 11/B 11/B 11/E
SHR 034 018/052 027/039 021/034 018/036 017/036 018/034
3/J 01/B 26/W 43/J 22/J 23/J 21/B
&&
.BYZ WATCHES/WARNINGS/ADVISORIES...
MT...NONE.
WY...NONE.
&&
$$
WEATHER.GOV/BILLINGS
AREA FORECAST DISCUSSION
NWS HASTINGS NE
359 PM CDT TUE MAR 19 2013
.SHORT TERM...(TONIGHT THROUGH WEDNESDAY)
ISSUED AT 357 PM CDT TUE MAR 19 2013
MORNING UPPER AIR ANALYSIS INDICATES LONGWAVE TROUGHING OVER THE
EASTERN-HALF OF THE CONUS WITH RIDGING OVER THE WEST.
NORTHWESTERLY MID AND UPPER LEVEL FLOW PERSISTS OVER THE CENTRAL
PLAINS AS A RESULT. TROPOSPHERIC FLOW OVER OUR AREA MAXES OUT AT
AROUND 120KTS PER 12Z SOUNDING DATA FROM KOAX AND KLBF. WATER
VAPOR IMAGERY ALSO INDICATES A SUBTLE MID LEVEL PERTURBATION OVER
EASTERN MONTANA...MOVING TO THE SOUTHEAST. AT THE SURFACE A TROUGH
IS NOTED EXTENDING FROM WESTERN IOWA INTO SOUTHEASTERN NEBRASKA
AND KANSAS...WITH A COLD FRONT ALSO NOTED OVER THE DAKOTAS. THE
LOW LEVEL WIND FIELD ACROSS OUR AREA REMAINS FROM THE NORTHWEST AS
A RESULT.
PROXIMITY SOUNDINGS FROM ACROSS CWA...PER RAP ANALYSIS AND LAPS
DATA...SUGGEST VERY STEEP LOW TO MID LEVEL LAPSE RATES ARE IN
PLACE...WITH NEARLY DRY ADIABATIC LAPSE RATES NOTED FROM THE
SURFACE TO BETWEEN 750MB AND 700MB ACROSS MUCH OF OUR AREA. AS A
RESULT...MODEST SBCAPE VALUES ON THE ORDER OF 100-200J/KG ARE IN
PLACE ACROSS MUCH OF THE CWA. AN EXPANDING CU FIELD AS BEEN NOTED
ON SATELLITE IMAGERY ACROSS MUCH OF NEBRASKA AS A RESULT...WITH
KUEX AND KLNX SUGGESTING ELEVATED PRECIPITATION HAS RESULTED. SOME
OF THIS PRECIPITATION IS MAKING IT TO THE SURFACE IN THE FORM OF
RAIN AND GRAUPEL...BOTH OF WHICH WAS OBSERVED AT THE OFFICE
BETWEEN 19Z AND 20Z. IN ADDITION...A COUPLE OF CG STRIKES HAVE
BEEN DETECTED FROM HALL COUNTY INTO BUFFALO COUNTY WITH SOME OF
THE MORE INTENSE CELLS. WITH ANY OMEGA STILL REMAINING WELL
NORTHWEST OF OUR AREA OVER THE NORTHERN HIGH PLAINS...IN THE
VICINITY OF THE AFOREMENTIONED MID LEVEL PERTURBATION...IT APPEARS
THE CURRENT ACTIVITY IS BEING PROMOTED BY DIABATIC HEATING ALONE.
SO...THIS ACTIVITY SHOULD CONTINUE THROUGH 22Z OR 23Z BEFORE THE
LOSS OF DIABATIC HEATING IS REALIZED LATER THIS EVENING. WENT
AHEAD WITH ISOLATED RAIN AND SNOW SHOWERS...ALONG WITH OCCASIONAL
LIGHTNING...IN THE FORECAST THROUGH 00Z.
THE SAME PROXIMITY SOUNDINGS FROM ACROSS THE CWA ALSO INDICATE
VERY DRY LOWER TROPOSPHERIC AIR IN PLACE ACROSS THE AREA...THUS
RESULTING IN DEEP INVERTED-V SOUNDINGS ACROSS THE ENTIRE CWA.
GIVEN THE ABUNDANT VIRGA NOTED HERE AT THE OFFICE...ALONG WITH THE
UPDRAFT STRENGTH NOTED FROM KUEX THROUGH THE PAST HOUR...FELT IT
PRUDENT TO INTRODUCE BRIEF WIND GUSTS TO AROUND 50 MPH IN THE HWO
THROUGH THIS EVENING.
THE MID LEVEL PERTURBATION...CURRENTLY OVER THE NORTHERN HIGH
PLAINS...IS EXPECTED TO SWEEP OVER OUR AREA TONIGHT. ANY OMEGA IN
ASSOCIATION WITH THIS FEATURE IS EXPECTED TO REMAIN WEAK AND WITH
NO OTHER SIGNIFICANT SOURCE OF LIFT DURING THE SHORT TERM
FORECAST PERIOD...DRY CONDITIONS ARE FORECAST TONIGHT INTO
TOMORROW.
THE PASSAGE OF THE MID LEVEL PERTURBATION WILL ALSO HELP PUSH THE
LOW LEVEL BAROCLINIC ZONE...CURRENTLY OVER THE DAKOTAS...ACROSS
OUR AREA TONIGHT. THIS WILL IN TURN ALLOW A COOLER AIRMASS INTO
OUR REGION THUS RESULTING IN SOMEWHAT COOLER WEDNESDAY MORNING
LOWS WHEN COMPARED TO TUESDAY MORNING. OVERNIGHT LOWS IN THE TEENS
AND 20S ARE CURRENTLY FORECAST FOR TONIGHT AS A RESULT. THE
SURFACE RIDGE IS THEN EXPECTED TO PUSH OFF TO OUR EAST DURING THE
DAY WEDNESDAY...WITH LOW LEVEL RETURN FLOW AND RESULTANT WARM AIR
ADVECTION ALLOWING WEDNESDAY AFTERNOON HIGHS TO CLIMB INTO THE 40S
AND LOWER 50S FOR MOST LOCATIONS ACROSS THE AREA.
.LONG TERM...(WEDNESDAY NIGHT THROUGH TUESDAY)
ISSUED AT 357 PM CDT TUE MAR 19 2013
WEDNESDAY NIGHT THROUGH TUESDAY. PRIMARY FORECAST CONCERN REVOLVES
AROUND A MESSY PATTERN WITH MULTIPLE PRECIPITATION CHANCES
DURING THE LATE WORK WEEK/WEEKEND TIME FRAME.
STILL EXPECTING THE START OF THE LONG TERM PERIOD TO BE DRY...WITH
MODELS IN GOOD AGREEMENT SHOWING NORTHWESTERLY FLOW SET UP IN THE
UPPER LEVELS ACROSS THE REGION WEDNESDAY EVENING INTO THE
OVERNIGHT HOURS...WITH AN ELONGATED LOW PRESSURE SYSTEM SPREAD
FROM THE NORTHEASTERN CONUS THROUGH THE GREAT LAKES...AND
SHORTWAVE RIDGING OVER THE ROCKIES AHEAD OF ANOTHER TROUGH ALONG
THE WEST COAST. AT THE SURFACE...THE CWA SITS BETWEEN A RIDGE OF
HIGH PRESSURE ALONG/JUST EAST OF THE MISSOURI RIVER...AND LOW
PRESSURE EXTENDING FROM THE NORTHERN ROCKIES DOWN INTO SERN
COLORADO...BRINGING SOUTHEASTERLY WINDS TO THE AREA.
AS WE GET INTO EARLY THURSDAY MORNING...STILL SEEING THE MAIN
MID/UPPER LEVEL TROUGH/LOW PRESSURE SYSTEM IN PLACE TO THE
WEST...WITH THE FIRST OF A COUPLE OF DISTURBANCES EJECTED OUT
AHEAD OF IT BEGINNING TO AFFECT THE REGION. MAIN CHANGE WITH THE
MODELS HAS BEEN WITH MORE AGREEMENT BACKING OFF THE COVERAGE OF
PRECIPITATION ACROSS THE CWA...THERE IS PLENTY OF DRIER AIR TO
OVERCOME...AND BETTER CHANCES LOOK TO BE ACROSS EASTERN PORTIONS
OF THE CWA DURING THE DAY ON THURSDAY AS THE MID LEVEL TROUGH AXIS
SWINGS THROUGH AND FRONTOGENETICAL LIFT INCREASES. REALLY TAPERED
BACK POPS...ESP ACROSS THE WRN THIRD OF THE CWA...IT IS POSSIBLE
AFTER 12Z THURSDAY SOME WESTERN LOCATIONS MAY NOT SEE MUCH OF
ANYTHING. DIDNT WANT TO COMPLETELY PULL POPS YET...WANT TO SEE
SOME CONSISTENCY WITH THIS TREND FIRST. DECIDED TO HOLD ON TO THE
MIXED PRECIPITATION ACROSS THE SWRN CWA DURING THE EARLY/MID
MORNING HOURS ON THURSDAY...BUT CONFIDENCE IS NOT HIGH IN IT
OCCURRING. IF PRECIPITATION OCCURS AT ALL IN THAT PART OF THE
CWA...CANT COMPLETELY RULE OUT A BRIEF PERIOD OF MORE OF A
MIX...BUT NOT EXPECTING IT TO AMOUNT TO MUCH.
BUMPED UP HIGH TEMPERATURES ON THURSDAY ONCE AGAIN WITH MODELS
TRENDING TOWARD THE POTENTIAL FOR DRIER CONDITIONS DURING THE
AFTERNOON HOURS...SWRN LOCATIONS COULD REACH INTO THE LOWER/MID
40S. THINK THE NORTHEAST HALF WILL STRUGGLE WITH PRECIP/MORE CLOUD
COVER LINGERING LONGER INTO THE DAY.
SHOULD SEE A LULL IN THE ACTIVITY LATER IN THE DAY THURSDAY AND
INTO THURSDAY EVENING...BUT IT WILL BE A BRIEF BREAK WITH THE
NEXT DISTURBANCE TAKING AIM ON THE REGION. MODELS SHOWING THE MAIN
TROUGH OVER THE NORTHWESTERN CONUS/NRN ROCKIES TRYING TO EVOLVE
INTO A CLOSED CIRCULATION AS ANOTHER 110+KT UPPER LEVEL JET STREAK
DIGS INTO THE WEST COAST. ANOTHER SHORTWAVE DISTURBANCE EJECTED
OUT FROM THIS SYSTEM LOOKS TO BRING ANOTHER CHANCE FOR
PRECIPITATION TO THE CWA. THERE CONTINUE TO BE SOME SLIGHT
DIFFERENCES...BUT MODELS HAVE TRENDED TOWARD MORE AGREEMENT
SHOWING THE TIMING COMING DURING THURSDAY NIGHT INTO THE FIRST
HALF OF THE DAY ON FRIDAY. THINKING THE PRIMARY PRECIPITATION TYPE
FOR MOST WILL BE SNOW...BUT CANT RULE OUT MORE OF A RA/SN
MIX...MAINLY ACROSS THE SOUTHERN CWA. LIKE THURSDAY...TRENDED BACK
POPS ON FRIDAY...THE BETTER CHANCES COME DURING THE 00-12Z FRIDAY
TIME FRAME...WITH VERY LITTLE IN THE WAY OF POPS DURING THE
AFTERNOON HOURS. BECAUSE OF THIS...ALSO BUMPED UP HIGHS ON
FRIDAY...WITH MID 30S IN THE NORTHEAST TO LOWER/MID 40S IN THE
SOUTHWEST.
FRIDAY AFTERNOON AND INTO THE OVERNIGHT HOURS WILL BRING ANOTHER
LULL IN THE ACTIVITY...BEFORE FOCUS QUICKLY TURNS TO A STRONGER
SYSTEM WHICH WILL BRING THE POTENTIAL FOR MORE WIDESPREAD
ACCUMULATING SNOWFALL TO THE REGION. BY EARLY SATURDAY
MORNING...MODELS HAVE STARTED TO COME INTO BETTER AGREEMENT
SHOWING THE DEVELOPMENT OF A LOW PRESSURE SYSTEM OVER THE BORDER
OF MONTANA/CANADA...WHILE A PIECE OF ENERGY SWINGING FURTHER SOUTH
INTO THE ROCKIES DOES THE SAME...AND ITS THIS SOUTHERN ONE WHICH
WILL AFFECT OUR CWA. LIFT WILL BEGIN TO INCREASE ACROSS THE CWA
OUT AHEAD OF THIS SYSTEM LATE FRIDAY NIGHT...ALREADY BRINGING
PRECIPITATION CHANCES TO MAINLY THE WESTERN HALF OF THE CWA.
THROUGH THE DAYTIME HOURS ON SATURDAY THIS UPPER LEVEL LOW WILL
CONTINUE TO PUSH EAST...BRINGING INCREASING PRECIPITATION
CHANCES...AND BY 00Z LOOKS TO BE OVER CENTRAL/ERN PORTIONS OF
COLORADO. THERE ARE SOME TIMING DIFFERENCES...THE ECMWF/GFS ARE IN
PRETTY GOOD AGREEMENT...WITH THE GEM A TOUCH SLOWER. WHAT HAPPENS
THEN THROUGH THE OVERNIGHT HOURS SATURDAY NIGHT AND THEN INTO
SUNDAY IS GOING TO DEPEND ULTIMATELY ON THE PATH/TIMING OF THIS
UPPER LEVEL LOW. THE TIMING/PATH DIFFERENCES BETWEEN THE MODELS
CONTINUE...BUT THEY ALL BRING MORE WIDESPREAD SNOWFALL
ACCUMULATION. THIS IS ESPECIALLY TRUE WITH THE GEM...WHICH IS THE
SLOWEST AND MOST WOUND UP SYSTEM COMPARED TO THE ECMWF/GFS...BUT
ITS PATH IS SOMEWHAT IN BETWEEN THE TWO...TAKING IT MORE THROUGH
CENTRAL KS. THERE ARE PLENTY OF THINGS TO WORK OUT IN THE COMING
DAYS...AND EXPECT MODEL CHANGES...BUT THOSE WITH WEEKEND PLANS
NEED TO KEEP AN EYE ON THIS SYSTEM. AS FAR AS TEMPERATURES
GO...EXPECTING HIGHS TO STRUGGLE TO GET OUT OF THE MID 30S BOTH
SATURDAY AND SUNDAY.
LOOKING AHEAD TO MONDAY AND TUESDAY...KEPT THE FORECAST DRY...BUT
THE MESSY UPPER LEVEL PATTERN REMAINS. MODELS KEEP THE REGION
UNDER THE INFLUENCE OF A BROAD TROUGH...WITH PIECES OF
ENERGY/LOW PRESSURE SYSTEMS ROTATING AROUND EACH OTHER. IN THIS
PATTERN...CERTAINLY WOULNDT BE SEEING MUCH/IF ANY WARM UP...WITH
HIGHS REMAINING IN THE 30S /AVERAGE FOR THIS TIME OF YEAR IS THE
LOWER 50S/...AND ITS NOT OUT OF THE REALM OF POSSIBILITY THAT SOME
OF THIS ENERGY COULD BRING ANOTHER CHANCE FOR PRECIPITATION...ESP
TUESDAY. BUT AT THIS POINT...WITH THERE ALREADY ENOUGH UNCERTAINTY
THROUGH THE WEEKEND...WASNT CONFIDENT ENOUGH TO GO WITH ANY POPS
FOR DAY 7.
&&
.AVIATION...(FOR THE 18Z TAF THROUGH 18Z WEDNESDAY AFTERNOON)
ISSUED AT 1216 PM CDT TUE MAR 19 2013
VFR CONDITIONS EXPECTED THROUGH THE NEXT 24 HOURS.
AFTERNOON CU FIELD WITH BASES NEAR 7000FT AGL ARE EXPECTED
TODAY...WITH SCATTERED CLOUDS NEAR 8000FT AGL ALSO EXPECTED
THROUGH THE OVERNIGHT HOURS. THE SURFACE WIND WILL REMAIN FROM THE
NORTH/NORTHWEST...SUSTAINED AT AROUND 17KTS AND GUSTING AROUND
25KTS. THE WIND WILL DIMINISH IN INTENSITY TONIGHT...SUSTAINED
AROUND 10KTS...BUT WILL REMAIN FROM THE NORTH. VISIBILITY
RESTRICTION IS NOT EXPECTED AT KGRI THROUGH THE NEXT 24 HOURS.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
KS...NONE.
&&
$$
SHORT TERM...BRYANT
LONG TERM...ADO
AVIATION...BRYANT
AREA FORECAST DISCUSSION
NWS OMAHA/VALLEY NE
419 AM CDT TUE MAR 19 2013
.DISCUSSION...
WHERE THE BAND OF PRECIPITATION (SNOW/RAIN-SNOW/SPRINKLES) WILL
SET UP TODAY AND THE POTENTIAL FOR ACCUMULATING SNOW
THURSDAY/THURSDAY NIGHT ARE THE PRIMARY FORECAST CHALLENGES.
AT H5...THERE ARE A COUPLE AREAS OF INTEREST. THE FIRST AREA IS A
SERIES OF SHORTWAVES EMBEDDED IN THE NORTHWEST FLOW FROM IDAHO AND
MONTANA INTO COLORADO. THE SECOND ARE SHORTWAVES EMBEDDED IN THE
FLOW FROM CALIFORNIA INTO NEVADA. THERE IS A STRONG 130KT JET THAT
IS CO-LOCATED FROM IDAHO INTO WESTERN NEBRASKA AND A 10KT JET
NOSING INTO CALIFORNIA. OTHERWISE...THE STORM SYSTEM THAT BROUGHT A
RAIN SNOW MIX TO THE REGION OVER THE WEEKEND IS STILL PRODUCING SNOW
FOR THE UPPER GREAT LAKES.
EARLY THIS MORNING...IR SATELLITE IMAGERY SHOWS ENHANCED CLOUDS FROM
MONTANA SOUTHEAST TO NEBRASKA. MID CLOUDS HAVE THICKENED OVER
NEBRASKA AND ECHOES ARE SHOWING UP ON RADAR...MOSTLY ALOFT AS
SURFACE REPORTS ARE DRY SAVE FOR LEXINGTON. THE NORTHERN JET
DIVES INTO THE PLAINS WHILE CALIFORNIA JET HEADS INTO
ARIZONA...PROVIDING SOME UPPER LEVEL DIVERGENCE FROM SOUTHERN
NEBRASKA INTO KANSAS. AS THE SHORTWAVE TROF MOVES ACROSS
NEBRASKA...H7-H3 OMEGA AND LAPSE RATES AND H85-7 FRONTOGENESIS
INCREASE OVER PARTS OF NEBRASKA THIS MORNING AND QUICKLY SHIFTS
INTO KANSAS AND MISSOURI THIS AFTERNOON. THE SHORT RANGE MODELS
VARY ON THE EXACT LOCATION OF THE FRONTOGENETIC BAND. THE RAP/NAM
ARE MAINLY SOUTHWEST OF A LINE FROM DAVID CITY TO FALLS
CITY......WHILE THE GFS IS SOUTHWEST OF BEATRICE...THE 4KM WRF IS
IN BETWEEN THE TWO...AND THE THE 21Z SREF IS FARTHER NORTHEAST.
THE RAP WAS MOSTLY NOT AVAILABLE. DO INCLUDE SOME CHANCE POPS
SOUTHEAST OF A LINE FROM DAVID CITY TO LINCOLN TO FALLS CITY...FOR
LIGHT SNOW THEN RAIN MIXED WITH SNOW THIS MORNING AND LIGHT RAIN
THIS AFTERNOON. INCLUDED CHANCE FOR SPRINKLES FARTHER NORTH THIS
AFTERNOON AND IN SOUTHWEST IOWA EARLY THIS EVENING.
THERE IS SOME FRONTOGENESIS TONIGHT AND WARM AIR ADVECTION AHEAD
OF THE NEXT EMBEDDED SHORT WAVED AND REINFORCING COLD AIR FOR
WEDNESDAY. FOR NOW...JUST INCLUDED A FEW CLOUDS OVERNIGHT. HIGH
WEDNESDAY WILL MOSTLY BE IN THE 30S...WITH A FEW LOWER 40S WITH
BREEZY NORTHWEST WINDS IN THE MORNING.
WEDNESDAY NIGHT...UPSLOPE FLOW DEVELOPS OVER THE WESTERN
PLAINS...AHEAD OF A STORM SYSTEM THAT IS APPROACHING FROM THE
PACIFIC NORTHWEST. H85 FLOW INCREASES AND DEEPER MOISTURE BEGINS
TO MOVE NORTHWARD ACROSS TEXAS.
THE MODELS ARE SIMILAR THURSDAY AND THURSDAY NIGHT IN DEVELOPING
AN ELONGED AREA OF LOW PRESSURE FROM EASTERN WYOMING SOUTH INTO
TEXAS. THE SOUTHERN PART OF THE LOW AREA IS STRONGER AND ORGANIZED
PRECIPITATION DEVELOP ACROSS OKLAHOMA...KANSAS...MISSOURI AND
ARKANSAS. THE MODELS DIFFER ON WHERE THE H85 LOW WILL TRACK WITH
THE SOUTHERN SYSTEM AND THE STRENGTH OF THE NORTHERN PLAINS WAVE
INFLUENCE. THERE IS THE POTENTIAL FOR A BAND OF LIGHT SNOW WITH
THESE FEATURES ACROSS THE CWA. FOR NOW HAVE CHANCE POPS IN THE
WEST AND SOUTH WHERE DYNAMICS APPEARS STRONGEST. HOPE TO HAVE A
BETTER SENSE AS TO HOW THIS SYSTEM WILL EVOLVE AFTER IT MOVES
ONSHORE WITH BETTER SAMPLING WEDNESDAY. HIGHS THURSDAY ARE IN THE
30S.
FOR THE EXTENDED...FRIDAY AND FRIDAY NIGHT...WE WILL STILL BE
UNDER THE INFLUENCE OF THE PACIFIC NORTHWEST CLOSED H5 LOW
PRESSURE SYSTEM. BY SATURDAY MORNING...THE AREA OF H5 LOW PRESSURE
REMAINS OVER MONTANA THRU UTAH AND COLORADO...BUT HAS CUT OF ON
AREA OVER UT/CO AND THIS DROPS SOUTH DURING THE DAY. THERE COULD
BE SOME LIGHT SNOW. WITH LOW CONFIDENCE HAVE KEPT POPS LOW. THE H5
LOW TRACKS ACROSS KANSAS OR OKLAHOMA. DEPENDING ON HOW FAR NORTH
THE SYSTEM TRACKS...IT COULD BRING SNOW TO KANSAS OR MISSOURI OR
TO NEBRASKA. THE GFS IS VERY BULLISH WITH PRECIPITATION AND A
MORE NORTHERN TRACK. FOR NOW HAVE FOLLOWED THE MORE OF A SOUTHERN
TRACK OF THE EC THROUGH SUNDAY...SO WILL HAVE TO KEEP A WATCH ON
THIS. BELOW NORMAL TEMPERATURES CONTINUE THRU MONDAY.
&&
.AVIATION...
06Z TAFS FOR KOMA...KLNK...AND KOFK.
VFR CONDITIONS SHOULD PREVAIL THROUGH AT LEAST MID MORNING TUESDAY
AT KOMA AND KOFK...BUT COULD DROP TO THE MVFR CATEGORY OR LOWER AT
KLNK BETWEEN 12Z-16Z WITH SNOW OR MIXED PCPN. MID LEVEL CLOUDINESS
CONTINUED TO SPREAD EAST AND LOWER...BUT CEILINGS SHOULD REMAIN
ABOVE 5000 FEET THROUGH 12Z. HIGHEST POTENTIAL FOR MVFR CEILINGS
AT KOMA IS 15Z-19Z. KOFK COULD HAVE CEILINGS IN THE 3000-5000
FOOT RANGE 15Z-19Z...ALONG WITH A RAIN/SNOW MIX. HIGH PRESSURE
BUILDS IN FOR TUESDAY NIGHT WITH NORTH/NORTHWEST WINDS.
MILLER
&&
.OAX WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
IA...NONE.
&&
$$
ZAPOTOCNY
AREA FORECAST DISCUSSION
NWS OMAHA/VALLEY NE
1145 PM CDT MON MAR 18 2013
.UPDATE...
CLOUDS ARE INCREASING A BIT FASTER THAN EXPECTED. WITH SOME WEAK
RADAR RETURNS TO THE WEST ALREADY...INTRODUCED SOME SCATTERED
FLURRIES LATE FOR PARTS OF SOUTHEAST NEBRASKA. EVENING RUNS OF
THE NAM AND RAP MODELS ALSO SHOWED MORE POTENTIAL FOR SNOW OR A
RAIN/SNOW MIX IN PARTS OF SOUTHEAST NEBRASKA TUESDAY MORNING...
SO UPDATED FOR THAT EARLIER.
MILLER
&&
.AVIATION...
06Z TAFS FOR KOMA...KLNK...AND KOFK.
VFR CONDITIONS SHOULD PREVAIL THROUGH AT LEAST MID MORNING TUESDAY
AT KOMA AND KOFK...BUT COULD DROP TO THE MVFR CATEGORY OR LOWER AT
KLNK BETWEEN 12Z-16Z WITH SNOW OR MIXED PCPN. MID LEVEL CLOUDINESS
CONTINUED TO SPREAD EAST AND LOWER...BUT CEILINGS SHOULD REMAIN
ABOVE 5000 FEET THROUGH 12Z. HIGHEST POTENTIAL FOR MVFR CEILINGS
AT KOMA IS 15Z-19Z. KOFK COULD HAVE CEILINGS IN THE 3000-5000
FOOT RANGE 15Z-19Z...ALONG WITH A RAIN/SNOW MIX. HIGH PRESSURE
BUILDS IN FOR TUESDAY NIGHT WITH NORTH/NORTHWEST WINDS.
MILLER
&&
.PREV DISCUSSION... /ISSUED 257 PM CDT MON MAR 18 2013/
SHORT TERM...TONIGHT THROUGH THURSDAY.
WINDY CONDITIONS ACROSS THE AREA THIS AFTERNOON WITH ADVISORY
IN PLACE ACROSS MOST OF THE NORTH HALF OF THE CWA. WILL LET
ADVISORY CONTINUE UNTIL EXPIRATION AT 23Z WITH WINDS DROPPING OFF
THROUGH THE EVENING AS HIGH PRESSURE BUILDS INTO THE REGION
TONIGHT. AREA WILL BE ON THE WESTERN EDGE OF THE MAIN POOL OF
COLD AIR SPREADING INTO THE MID MISSISSIPPI VALLEY. NEXT WEAK
WAVE DROPS INTO THE NORTHERN PLAINS AND UPPER MIDWEST ON TUESDAY
ALLOWING SOME WARMER AIR TO BRIEFLY RETURN NORTH IN ADVANCE OF THE
FEATURE BEFORE THE NEXT COLD SURGE COMES IN TUESDAY NIGHT. MODELS
CONTINUE TO SUGGEST SOME POTENTIAL FOR SHOWERS ALONG LEADING EDGE
OF THE COLD AIR SO HAVE LEFT CURRENT MENTION OF FLURRIES OR
SPRINKLES AS IS FOR TUESDAY AFTERNOON.
COLD AIR LINGERS THROUGH WEDNESDAY BEFORE MID LEVEL SHORT WAVE
RIDGE MOVES IN WEDNESDAY NIGHT AHEAD OF NEXT MAJOR WAVE COMING
INTO THE NORTHERN ROCKIES. THIS SYSTEM IS SOMEWHAT FRAGMENTED
INITIALLY WITH SEVERAL SHORT WAVES INDICATED BY MODELS ACROSS THE
WESTERN CONUS BEFORE SPLITTING INTO A NORTHERN AND SOUTHERN STREAM
COMPLEX THURSDAY NIGHT INTO FRIDAY. CHANCE OF SNOW RETURNS TO
PARTS OF THE AREA ON THURSDAY AS INITIAL WAVE DIGS INTO THE
SOUTHERN PLAINS WITH SURFACE LOW ALONG THE TEXAS OKLAHOMA BORDER.
FORECAST AREA GENERALLY IN BETWEEN THESE TWO FEATURES ON THURSDAY
SO POPS ON THE LOW SIDE FOR NOW EXCEPT ALONG THE SOUTHEAST BORDER
WHERE HIGHER CHANCE POPS IN PLACE.
FOBERT
LONG TERM...THURSDAY NIGHT THROUGH MONDAY.
GFS/CMC/ECM SFC TEMP METEOGRAMS ARE IN GOOD AGREEMENT THAT THE MAIN
THEME IN THE EXTENDED PDS IS LITTLE HOPE FOR A WARMING TREND. THUS
EXPECT BELOW NORM TEMPS WILL BE THE RULE DAYS 4-7. ALL THIS IN PART
TO MEAN UPPER TROUGHING ENVELOPING THE CNTRL CONUS PER
GEFS/CMCENS/ECMENS. MEANWHILE DETERMINISTIC ECM/CMC PROGS SEEM TO
BE IN RELATIVELY DECENT AGREEMENT AFT DAY 4 WITH THE GFS THE
OUTLIER.
POSSIBLE PCPN THURS NIGHT IS INITIAL CONCERN. QPF FIELDS ARE FOR THE
MOST PART FOCUSED SOUTH/WEST OF THE CWA ALONG AXIS OF WEAK/MODERATE
AGEOSTROPHIC LIFT. UPPER SUPPORT IS INSIGNIFICANT...THUS NOT VERY
IMPRESSED WITH PCPN POTENTIAL. AT THIS POINT CANNOT TOTALLY DISCOUNT
SOME LIGHT SNOW ACTIVITY REACHING THE WRN CWA PERIPHERY.
HOWEVER...HAVE OPTED TO BUMP POPS DOWN JUST A BIT. AS A MATTER OF
FACT THOUGH...NOT IMPRESSED WITH PCPN POTENTIAL AT ALL FRIDAY AND
BEYOND. AT THIS POINT FEEL COMPELLED THEN TO DROP ALL GOING POPS TO
SLGT CAT.
DEE
&&
.OAX WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
IA...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS BURLINGTON VT
355 AM EDT TUE MAR 19 2013
.SYNOPSIS...
THE COMBINATION OF A WARM FRONT LIFTING THROUGH THE REGION...AND LOW
PRESSURE LIFTING NORTHEAST ALONG THE COAST...WILL PROVIDE MUCH OF
OUR AREA WITH WIDESPREAD MODERATE TO LOCALLY HEAVY SNOW THROUGH
TONIGHT. STEADIER SNOWS WILL TAPER OFF BY WEDNESDAY...BUT ON AND OFF
SNOW SHOWERS...CLOUDY SKIES AND SEASONABLY COOL TEMPERATURES ARE
EXPECTED TO CONTINUE THROUGH THE END OF THE WORK WEEK AS UPPER LEVEL
LOW PRESSURE REMAINS ATOP THE NORTHEAST. SOME IMPROVEMENT IS
EXPECTED BY LATER IN THE WEEKEND INTO EARLY NEXT WEEK AS CONDITIONS
TREND DRIER AND TEMPERATURES RETURN TO NEAR NORMAL LEVELS.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 355 AM EDT TUESDAY...FORECAST REMAINS MORE OR LESS ON TRACK
WE HEAD INTO TODAY AS SFC WARM FRONT CONTINUES TO MAKE SLOW
PROGRESS NORTH AND EAST INTO THE REGION. DECENT ISENTROPIC LIFT
AND AMBIENT OMEGA IN THE DENDRITIC SNOW GROWTH ZONE ALL POINT TO
CONTINUE CATEGORICAL POPS FOR LIGHT TO MODERATE SNOW THROUGH THE
DAYLIGHT HOURS THOUGH ACCUMULATIONS WILL BE A TOUGH CALL GIVEN
HIGHER MARCH SUN ANGLE AND MARGINAL TEMPERATURES AT OR SLIGHTLY
ABOVE FREEZING BY THIS AFTERNOON...ESP IN THE LOWER ELEVATIONS. MY
GUT FEELING TELLS ME MY DAYTIME ACCUMULATIONS MAY BE A BIT
OVERDONE...ESP IN THE 12-18Z TIME FRAME WHEN A LULL IN THE PCPN
MAY OCCUR DURING TIME OF MAXIMUM INSOLATION. BUT TO PLAY DEVIL`S
ADVOCATE IT MAY BE MORE OR LESS ACCURATE FOR THE 12-HR PERIOD AS
POTENTIAL HIGHER RATES WILL LIKELY RAMP UP QUICKLY BY LATE
AFTERNOON/EARLY EVENING AS DEVELOPING COASTAL LOW PRESSURE RIDES
NORTHEASTERLY TO NEAR KBOS BY 00Z. INDEED...THIS MORNING`S GFS
SOLN IS STILL FAIRLY BULLISH ON DEVELOPMENT OF A BACK-END STRONG
DEFORMATION AXIS PROGRESSING SLOWLY EASTWARD FROM THE ERN DACKS
INTO THE CPV AND POINTS EAST THIS AFTERNOON/EARLY EVENING...AND
HAS BROAD SUPPORT FROM RECENT RAP RUNS. SOUNDING PROFILES SUGGEST
VERY STRONG OMEGA AND MID-LEVEL FRONTOGENETICAL FORCING WITH THIS
FEATURE WITH POTENTIAL 1-2" PER HOUR SNOWFALL RATES WITHIN A FEW
HOURS +/- OF THE 21-00Z HOUR TIME FRAME. THE DEVELOPMENT OF THIS
FEATURE APPEARS AT LEAST IN PART DUE TO THE PARENT GREAT LAKE
OCCLUSION`S SFC FRONT AND UPPER TROUGH AXIS PROGRESSING EASTWARD
AND LEADING TO STRONG LOW TO MID LEVEL CONVERGENCE AS IT UNDERCUTS
THE DEEPER ATLANTIC MOISTURE. INDEED...THERE IS A STARK WIND SHIFT
FROM MEAN SOUTH/SOUTHEASTERLY TO WEST/SOUTHWESTERLY IN THE LOWER
TO MID LEVELS ALONG THIS BOUNDARY...AND WHILE THIS MORNING`S NAM
AND OUR LOCALLY RUN WRF MODELS DEPICT THE DEVELOPMENT OF THE HEAVY
PCPN BAND SOMEWHAT DIFFERENTLY THAN THE GFS...MY FEELING THEY BOTH
ARE CORRECT IN THE BAND DEVELOPMENT...THOUGH ARRIVING AT IT IN
DIFFERENT WAYS. SO I`LL CONTINUE WITH PRIOR FORECASTER`S IDEA THAT
MOST AREAS FROM THE DACKS EASTWARD SHOULD SEE A 2-4 HOUR PERIOD OF
MODERATE TO HEAVY SNOWFALL LATER THIS AFTERNOON THROUGH EARLY TO
MID EVENING WHICH WILL PRODUCE ADDITIONAL BACK-END AMOUNTS OF 4-8
INCHES. AS IS TYPICAL WITH TWO-PHASED AND/OR LATE SEASON EVENTS
SUCH AS THIS...THERE WILL BE WINNERS AND LOSERS IN THE SNOWFALL.
MOST PROBLEMATIC MAY END UP BEING AREAS ACROSS THE SLV WHERE
HEAVIEST TOTALS WILL LIKELY TO COME ON THE FRONT END WARM THERMAL
ADVECTION PCPN THIS MORNING...WITH THIS AREA POSSIBLY A BIT TOO
FAR TO THE WEST OF THE PRIMARY FRONTAL INTERACTION WITH THE
COASTAL LOW THIS EVENING. TIME WILL TELL.
AS WE PROGRESS INTO THE LATER EVENING AND OVERNIGHT HOURS...FRONTAL
ZONE AND BETTER MOISTURE/LOW LEVEL CONVERGENCE CONTINUE TO PUSH
EAST TAKING STEADIER AND HEAVIER SNOWS INTO EASTERN NEW ENGLAND AND
OUT OF OUR FORECAST AREA. THUS EXPECTING A GRADUAL TAPERING TO VERY
LIGHT SNOW OR SNOW SHOWERS AFTER MIDNIGHT WITH ADDITIONAL
ACCUMULATIONS ON THE MINOR SIDE AS TEMPERATURES BOTTOM OUT IN THE
LOWER TO MID 20S BY SUNRISE ON WEDNESDAY. TOTAL SNOWFALL AMOUNTS
AVERAGING 7-10" IN THE SLV...9-12" DACKS AND CPV...AND 10-15"
ACROSS ERN VT WHERE STEADIER SNOWS WILL PERSIST THE LONGEST.
&&
.SHORT TERM /WEDNESDAY THROUGH THURSDAY/...
AS OF 355 AM EDT TUESDAY...THIS MORNING`S MODELS REMAIN IN BROAD
AGREEMENT FROM WEDNESDAY INTO THURSDAY IN OFFERING A CONTINUED
CLOUDY AND UNSETTLED WEATHER PATTERN FOR OUR REGION AS A LARGE-
SCALE UPPER CYCLONIC GYRE REMAINS ATOP THE NORTHEAST. THUS I`LL
OFFER A MORE OR LESS PERSISTENCE FORECAST THROUGH THIS TIME FRAME
WITH ON AND OFF/PERIODIC FLURRIES AND SHSN...ESPECIALLY ACROSS OUR
CENTRAL AND NORTHERN COUNTIES. WHILE HEAVY SNOW IS NOT
EXPECTED...ADDITIONAL LIGHT SNOW ACCUMULATIONS ARE LIKELY...ESP AT
NIGHT AND ACROSS THE HIGHER ELEVATIONS OF THE CENTRAL AND NORTHERN
MTNS AS TEMPERATURES CONTINUE TO RUN ON THE COOL SIDE WITH DAILY
MEANS AVERAGING 3 TO 7 DEGREES BELOW NORMAL.
&&
.LONG TERM /THURSDAY NIGHT THROUGH MONDAY/...
AS OF 355 AM EDT TUESDAY...BROAD UPPER LOW WILL CONTINUE TO BRING
LIGHT WINTRY PRECIPITATION TO THE NORTH COUNTRY AS THE SYSTEM
SLOWLY TRUDGES EAST INTO THE CANADIAN MARITIMES...THURSDAY NIGHT
INTO THE BEGINNING OF THE UPCOMING WEEKEND. MDLS BRING HIGH
PRESSURE INTO THE AREA ON SATURDAY FROM THE WEST AS UPPER LOW
EXITS AND REMAINS INTO NEXT MONDAY. BOTH GFS/ECMWF DO HINT AT
ANOTHER COASTL LOW SHUNTED TO OUR SOUTH DO TO BLOCKING RIDGE OVER
NORTHEAST. OVERALL FOR EXPECTED -SW ACTIVITY...WILL TAPER DOWN
POPS FOR MUCH OF CWA GOING INTO SATURDAY WITH BEST CHANCES OVER
HIR TRRN/NORTHERN ZONES DO TO NW FLOW ON BACKSIDE OF SYSTEM. SOME
LIGHT ACCUM POSSIBLE OVER DACKS/NC VT. CLRING TREND/SL WARMING
TREND ENSUES OVER THE REST OF THE WEEKEND W/ SFC HIGH OVER AREA.
FULL MARCH SUNSHINE WILL BRING SLIGHTLY INCR TEMPS FOR MUCH OF
EXTENDED PERIOD TOPPING OFF WITH HIGHS AROUND 40F FOR SUNDAY AND
NEXT MONDAY...WHILE OVERNGT LOWS RANGE MAINLY IN THE TEENS/L20S.
SOME SINGLE NUMBERS POSSIBLE IN DACKS/NE KINGDOM SAT/SUN NITES
FROM CLRING SKIES/RADIATIONAL COOLING.
&&
.AVIATION /08Z TUESDAY THROUGH SATURDAY/...
THROUGH 06Z WEDNESDAY...WINTER STORM PUSHING THRU THE AREA WILL
BRING A MIX OF MVFR/IFR VSBY THRU FORECAST PERIOD RANGING MAINLY
FROM 3-5SM W/ PERIODS OF 1-2SM AT TIMES. CEILINGS WILL RANGE FROM
VFR DOWN TO MVFR W/ BKN015-040. WINDS INITIALLY ENE TO SSE
10-20KTS THRU THIS AFTNOON THEN BECM WSW 5-10KTS FOR MSS/SLK...AND
NNW 5-10KTS FOR REST OF FORECAST SITES.
OUTLOOK 06Z WEDNESDAY THROUGH SATURDAY...
06Z WEDNESDAY THROUGH 12Z WEDNESDAY...IFR OR LOWER SNOW CONTINUES
THROUGH 04-08Z AS LOW DRAWS NORTHWARD ALONG COASTAL NEW ENGLAND.
SOME BRIEFLY HEAVIER SNOW LIKELY DURING THIS TIME.
12Z WEDNESDAY THROUGH SATURDAY...MIX OF VFR/MVFR/IFR CIGS AND VSBYS
LIKELY WITH UPPER LEVEL LOW PRESSURE CONTINUING TO PROVIDE THE
REGION WITH ON AND OFF SNOW SHOWERS.
&&
.BTV WATCHES/WARNINGS/ADVISORIES...
VT...WINTER STORM WARNING UNTIL 8 AM EDT WEDNESDAY FOR VTZ001>012-
016>019.
NY...WINTER STORM WARNING UNTIL 8 AM EDT WEDNESDAY FOR NYZ026>031-
034-035-087.
&&
$$
SYNOPSIS...JMG
NEAR TERM...JMG
SHORT TERM...JMG
LONG TERM...JN
AVIATION...JN/MUCCILLI
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
933 PM EDT WED MAR 20 2013
.SYNOPSIS...
AN UPPER LEVEL LOW CURRENTLY OVER SOUTHEAST CANADA WILL STAY
ANCHORED NORTH OF PENNSYLVANIA THROUGH THE REST OF THE WORKWEEK.
THE RESULTING GUSTY WEST TO NORTHWEST WIND WILL CONTINUE TO FILTER
COLD AIR INTO THE REGION. THIS WILL ALSO PRODUCE OCCASIONAL SNOW
SHOWERS ACROSS THE WESTERN MOUNTAINS. A STORM SYSTEM MAY MOVE OUT OF
THE MID-MISSISSIPPI VALLEY LATER THIS WEEKEND AND COULD BRING
ANOTHER ROUND OF WINTRY PRECIPITATION TO THE REGION LATE SUNDAY
NIGHT AND MONDAY.
&&
.NEAR TERM /UNTIL 6 AM THURSDAY MORNING/...
A SHARP MID-LEVEL TROUGH WAS MOVING ACROSS CENTRAL AND WESTERN
PENN THIS EVENING ACCOMPANIED BY CLOUDS AND OCCASIONAL /MAINLY
LIGHT/ SNOW SHOWERS.
THE AREA THAT WE/LL HAVE TO KEEP A CLOSE EYE OVER THE NEXT 6 HOURS
OR SO IS THE LOWER SUSQUEHANNA VALLEY WHICH WILL BE IN CLOSE
PROXIMITY TO SEVERAL FAVORABLE FEATURES COMING TOGETHER TO PRODUCE
A PERIOD OF MORE NUMEROUS SNOW SHOWERS OR EVEN SOME STEADY LIGHT
SNOW BETWEEN ABOUT 03Z AND 07Z THURS. AN AREA OF ELEVATED /NEARLY
ZERO/ LIFTED INDICES IN THE 800-750 MB LAYER...WILL OCCUR BENEATH
THE LEFT EXIT REGION OF A 60 KT JET-LET SLIDING NE ACROSS THE MID
ATLANTIC PIEDMONT...WHILE A NORTHEAST TO SOUTHWEST BAND OF FGEN
DEVELOPS NEAR THE I-81 CORRIDOR IN PA BETWEEN 03-06Z. LATEST RUNS
OF THE NAM AND HRRR ARE HOWEVER SQUEEZING OUT JUST A MINIMAL FEW
HUNDREDTHS...TO ONE TENTH OF AN INCH OF QPF JUST EAST OF LANC CTY
LATER TONIGHT. WILL MAINTAIN SOME VERY LIGHT SNOW ACCUMS ACROSS
THE LOWER SUSQ VALLEY OVERNIGHT.
THE SCATTERED SNOW SHOWERS ACROSS MOST OTHER AREAS OF THE STATE
COULD BRING A QUICK COATING TO 1 INCH.
FAIRLY DEEP...COLD AND WELL-ALIGNED WESTERLY MEAN SFC-850 MB FLOW
WILL HELP TO CONSOLIDATE THE POPCORN TYPE OF SNOW SHOWERS...INTO A
FEW ORGANIZED BANDS OF LES ACROSS THE NW MTNS LATE TONIGHT...BUT
THE BULK OF THE HEAVY SNOWS SHOULD STAY JUST NORTH OF THE PA/NY
BORDER THROUGH ABOUT 10Z BEFORE DRIFTING SLOWLY TO THE SOUTH.
STILL...NW WARREN COUNTY WILL LIKELY RECEIVE 2-4 INCHES OVERNIGHT
AS 850 AND 700 MB TEMPS FALL ANOTHER FEW TO SEVERAL DEG C TO
VERY COLD VALUES OF AROUND -15C AND -25C RESPECTIVELY. WILL BE
POSTING A LES ADVISORY FOR WARREN COUNTY SHORTLY AND RUN IT
THROUGH 15Z THURSDAY.
TONIGHT WILL BE CHILLY...WITH LOW TEMPERATURES RUNNING ABOUT
10-15 DEGREES BELOW NORMAL. TEMPERATURES WILL RANGE FROM THE LOW
TO MID 20S IN THE SOUTHEAST TO THE TEENS IN THE NORTHWEST.
&&
.SHORT TERM /6 AM THURSDAY MORNING THROUGH THURSDAY NIGHT/...
THE CHILLY...BREEZY PATTERN WILL CONTINUE FOR THURSDAY AS THE
GUSTY WEST TO NORTHWEST FLOW CONTINUES OVER THE STATE. THIS WILL
ALSO MAINTAIN/OR REJUVENATE LAKE EFFECT AND UPSLOPE SNOW SHOWERS
ACROSS THE NORTHWEST MOUNTAINS AND LAUREL HIGHLANDS. ADDITIONAL
LIGHT SNOW ACCUMULATIONS ARE LIKELY IN THESE AREAS TOMORROW.
SPRING-LIKE TEMPERATURES ARE NOWHERE IN SIGHT AS TEMPERATURES
TOMORROW WILL CONTINUE TO RUN 10-15 DEGREES BELOW AVERAGE.
&&
.LONG TERM /FRIDAY THROUGH WEDNESDAY/...
NW FLOW CONTINUES THROUGH FRIDAY...AND SHOULD PRODUCE THE TYPICAL
SCT SHSN ACROSS THE NW/FLURRIES CENTRAL MTS. WE MIGHT BE ABLE TO
3-4F ONTO THE PREV DAYS HIGHS. A SHORT PERIOD OF RISING HEIGHTS
WILL MOVE ACROSS PA OVER THE WEEKEND HELPING TO BRING SNOW SHOWER
ACTIVITY TO AN END. THE SHORTWAVE RIDGE IS AHEAD OF EXPECTED
SIGNIFICANT LONGWAVE TROF DEVELOPMENT FORECAST TO TAKE PLACE
ACROSS THE PLAINS OVER THE WEEKEND AS ENERGY DIVES SOUTH FROM
CANADA. THE LARGE-SCALE PATTERN DOES FAVOR DEVELOPMENT OF A SFC
LOW OVER THE MID MS VALLEY AND A MILLER TYPE-B SCENARIO AFTER
THAT AS THE UPPER TROUGH SWINGS TO THE EAST. BUT...THE DEVIL
REMAINS IN THE DETAILS. SO...EYES ARE CENTERED ON PERHAPS ANOTHER
LATE WINTER/EARLY SPRING STORM FOR PA FROM PERHAPS LATE SUNDAY
INTO MONDAY NIGHT. MOST MDLS AND ENSEMBLE MEMBERS DO BRING SOME
PRECIP INTO AT LEAST SRN HALF OF PA FROM THIS SYSTEM.
HOWEVER...THE BIG TROUBLES REMAIN TIMING...NORTHWARD EXTENT OF
PRECIP DUE TO TIMING OF LOW TRANSFER...AND OF COURSE TEMPS AND
P-TYPES DURING THE PRECIP. IN OTHER WORDS...EVERYTHING IS STILL
UNCERTAIN. DID HAVE ENOUGH CONFIDENCE TO MAKE POPS AROUND 50 PCT
IN THE S FOR TWO PERIODS...BUT IT IS STILL A DAY 5-6 /POTENTIAL/
STORM. PLENTY OF TIME FOR THE PROGS TO WAGGLE ALL DIFFERENT
DIRECTIONS FOR MANY DAYS.
&&
.AVIATION /01Z THURSDAY THROUGH MONDAY/...
TROUGH ROTATING AROUND BASE OF LARGE AREA OF LOW PRESSURE CENTERED
OVER S CANADA WILL REINFORCE NW FLOW OVER CENTRAL PA...KEEPING
WINDS BREEZY WITH GUSTS OF 10-20 KTS COMMON THROUGH THIS EVENING.
HIGHER TERRAIN NEAR KBFD-KJST WILL CONTINUE TO SEE OCNL TERRAIN
ENHANCED SNOW SHOWERS...BRINGING MAINLY MVFR CONDITIONS WITH
FLUCTUATIONS TO IFR AT TIMES. ELSEWHERE JUST FLURRIES POSSIBLE
UNDER MAINLY VFR CONDITIONS.
COLD AIR ADVECTION LATER TONIGHT WILL LOCK IN MVFR TO IFR CIGS
OVER THE NW MTNS /KBFD/ WITH MVFR AT KJST. THESE WILL CONTINUE
INTO THU MID MORNING BEFORE IMPROVING A BIT...THOUGH SCT SNOW
SHOWERS WILL CONTINUE TO BRING VARIABLE VISIBILITIES TO HIGHER
TERRAIN. LOWER CIGS WILL ALSO AGAIN BECOME POSS IN CENTRAL
SECTIONS THU AFTERNOON AS WINDS INCREASE AND TURN MORE NORTHERLY.
OUTLOOK...
THU-SAT...GUSTY WEST TO NW FLOW. MVFR WITH OCNL -SHSN WEST.
MAINLY VFR CENTRAL AND SE.
SUN...NO SIG WX.
SUN NIGHT-MON...MVFR AND BRIEF IFR POSS WITH A WINTRY MIX.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...ROSS/COLBERT
NEAR TERM...LAMBERT
SHORT TERM...LA CORTE/LAMBERT
LONG TERM...DANGELO/CERU
AVIATION...RXR
AREA FORECAST DISCUSSION
NWS SPOKANE WA
1036 PM PDT Mon Mar 18 2013
.SYNOPSIS...
Active March weather will continue with cool, breezy and showery
conditions. After the showers decrease this evening, a vigorous
storm system will bring rain, snow, and windy conditions to the
Pacific Northwest Wednesday into Wednesday night. Cool and showery
conditions are expected Thursday into the upcoming weekend.
&&
.DISCUSSION...
Update: general forecast is on track save for a minor adjustments.
Winds remain locally breezy but trends and RAP guidance continues
to indicate winds abating, with the slackening gradients and
decoupling. I adjust overnight low up a 2-3 degrees where winds
remain a bit breezier, toward the basin, and up about a degree
based on newest guidance and trends. Otherwise the isolated
showers are dissipating through the Panhandle this hour and
should largely be winding down, save for perhaps around the
Panhandle mountains (closer to the MT border) where the mean
northwest flow linger.
The next system is on the approach and newest guidance continues to
the lower level flow turning easterly going into Tuesday. With
this evening`s 00Z sounding showing some drying and subsidence, it
will take time for the atmosphere to moisten up again before the
next threat of precipitation really gets going. So much of Tuesday
looks dry.
By Tuesday night into Wednesday the incoming system taps some
moisture (with precipitable water values rising to around 150% of
normal). The system appears to have a "one-two" punch. First the
leading warm front and weakening mid-level wave come in Tuesday
night into early Wednesday morning, with the first precipitation
peak. Second, after a strictly relative-lull going into mid-
morning, the more dynamic cold front and negatively- tilted upper
wave coming through on Wednesday, with precipitation rates for the
entire system peaking around Wednesday afternoon.
With some exceptions, snow levels are expected to rise to around
2500 to 5000 feet. This is supported by 850mb temperatures in the
lower to mid-single digits (Celsius) and a stout southerly flow
(850mb winds around 20-40 kts). The exceptions will be around the
Cascades through Canadian border counties, especially for Tuesday
night/early Wednesday morning. This includes the Wenatchee area
through Okanogan Valley. A southeast flow will promote cold air
damming, with 850mb temps around 0 to -3C. With this set-up and
the potential for wet-bulb cooling, snow levels here will be closer
to valley floors.
Thus some snow accumulations are possible in these areas, which
may make the Wednesday morning commute slick and slower. The
mountain areas and passes may also see some moderate accumulations.
By late morning to early afternoon snow levels here are also
expected to rise out of the valleys. Before then, however, some
highlights may be needed. /J. Cote`
&&
.AVIATION...
06Z TAFS: Upper wave exits tonight, with a brief break coming
Tuesday before a wetter system approaches Tuesday night. Primarily
VFR conditions through the period, but clouds will be on the
increase and lowering going into Tuesday afternoon and evening
(especially after 23-01Z). The primary threat of precipitation
will come after 00Z Wednesday (Tuesday evening) into the KEAT/KMWH
area, approaching the remainder of the TAF sites toward the end of
this TAF period. Local MVFR cigs are possible some of these showers.
Winds are generally expected to be 10kts or less, except around
the KPUW to KMWH area as they approaching system will increase
gradients in the afternoon. Some higher gusts are possible in
these areas by Tuesday afternoon, especially near KPUW. /J. Cote`
&&
.PRELIMINARY POINT TEMPS/POPS...
Spokane 24 49 37 51 32 46 / 10 0 80 90 40 30
Coeur d`Alene 24 48 35 49 31 45 / 10 0 80 100 60 40
Pullman 26 51 37 51 32 43 / 10 10 80 90 40 40
Lewiston 31 57 39 58 36 49 / 10 10 60 80 40 30
Colville 21 51 32 50 29 48 / 10 0 80 90 40 30
Sandpoint 22 44 32 47 29 44 / 20 0 80 100 70 50
Kellogg 22 44 32 46 29 40 / 40 0 80 100 80 50
Moses Lake 25 54 36 56 33 51 / 0 10 70 60 10 10
Wenatchee 29 50 35 54 32 49 / 0 30 70 60 10 10
Omak 25 50 32 54 29 49 / 0 10 80 80 10 10
&&
.OTX WATCHES/WARNINGS/ADVISORIES...
ID...None.
WA...None.
&&
$$
AREA FORECAST DISCUSSION
NWS GREEN BAY WI
1036 PM CDT WED MAR 20 2013
UPDATED AVIATION PORTION FOR 06Z TAF ISSUANCE
.SHORT TERM...TONIGHT AND THURSDAY.
LATEST RUC ANALYSIS AND SATELLITE/RADAR IMAGERY SHOW A BROAD AND
ELONGATED UPPER LEVEL LOW PRESSURE SYSTEM SPINNING FROM THE CENTRAL
GREAT LAKES TO NEW ENGLAND EARLY THIS AFTERNOON. CLOUDS HAVE BEEN
SPREADING SOUTH ACROSS THE UPPER PENINSULA AND NORTHERN WISCONSIN SO
FAR TODAY...AS A RESULT OF SHORTWAVE LOBES ROTATING AROUND THE
PARENT VORTEX...AND ALSO STEEPENING LOW LEVEL LAPSE RATES. THESE
CONDITIONS ALSO PROMOTE CONDITIONS FOR SIGNIFICANT LAKE EFFECT
SNOWS...WHICH ARE OCCURRING WITHIN THE SNOW BELTS OF THE WESTERN
UPPER PENINSULA. IN FACT...IRONWOOD HAS OSCILLATED BETWEEN 1/2SM
AND 3/4SM FOR MUCH OF THE DAY. LAKE EFFECT POTENTIAL IS THE MAIN
FORECAST CONCERN OVER THE NEXT 24 HOURS AS WIND TRAJECTORIES BECOME
MORE FAVORABLE FOR N-C WISCONSIN.
TONIGHT...SHORTWAVE TROUGH WILL DIVE SOUTH ACROSS CENTRAL AND
SOUTHERN WISCONSIN THIS EVENING...ON THE WESTERN FLANK OF THE UPPER
LOW. NOT SOLD THAT PRECIP WILL TURN OFF AT SUNSET...THOUGH DIURNAL
INSTABILITY WILL BE LOST. WILL KEEP LIGHT SNOW SHOWERS AND FLURRIES
GOING FOR A GOOD CHUNK OF THE EVENING. BEHIND THE SHORTWAVE...LOW
LEVEL WINDS TURN TO THE NNW. WIND TRAJECTORIES LOOK REALLY GOOD FOR
A SOLID LAKE EFFECT EVENT FOR N-C WISCONSIN. THERMAL PROFILES ARE
ALSO IN THE OPTIMAL DENDRITIC GROWTH ZONE THROUGH THE NIGHT...AND
THERE IS SUFFICIENT MOISTURE IN THE 850-700MB LAYER AS WELL. ON THE
MINUS SIDE...SUBSIDENCE WILL BE INCREASING THROUGH THE NIGHT AND
LAKE INDUCED CAPE WILL GRADUALLY DIMINISH. THE LOCAL LAKE EFFECT
PARAMETER DOES SHOW A SLIGHT DIMINISHING TREND TONIGHT...BUT NOT
THAT SIGNIFICANT. A LIMITING FACTOR MAY BE THE 15 KT BL WINDS...IN
WHICH THE NORTHERN PART OF VILAS COUNTY GETS ADVISORY CRITERIA
SNOW...AND THE SOUTHERN HALF DOES NOT. SO THINK WILL GO WITHOUT AN
ADVISORY AND ISSUE AN SPS FOR THE COUNTY TONIGHT...AND WILL
HIGHLIGHT THAT SEVERAL INCHES OF SNOW ARE POSSIBLE ACROSS THE
NORTHERN PART OF THE COUNTY. PARTIAL CLEARING SHOULD OCCUR OUTSIDE
THE LAKE EFFECT BELT DURING THE OVERNIGHT HOURS...BUT DO NOT THINK
WILL SEE DECOUPLING. AS A RESULT...LOW TEMPS WILL BE COMPARABLE TO
LAST NIGHTS LOWS.
THURSDAY...LAKE EFFECT SNOW SHOWERS WILL CONTINUE OVER N-C WISCONSIN
THROUGH EARLY AFTERNOON...BUT SHOULD DIMINISH AS DRY AIR INVADES
FROM THE NORTH. ELSEWHERE...AFTER A MOSTLY CLEAR TO PARTLY CLOUDY
START TO THE DAY...CLOUDS SHOULD BE INCREASING BY LATE MORNING OR
EARLY AFTERNOON AS WILL STILL HAVE PLENTY OF LOW LEVEL MOISTURE AND
STEEP LOW LEVEL LAPSE RATES AROUND. INCREASED CLOUD COVER...BUT
KEPT THE SNOW CHANCES CONFINED TO THE SNOW BELT. HIGHS SEVERAL
DEGREES WARMER THAN TODAY WITH HIGHS MAINLY IN THE MID TO UPPER 20S.
.LONG TERM...THURSDAY NIGHT THROUGH NEXT WEDNESDAY...MAIN FCST
CONCERN IS TEMPERATURES.
A LARGE UPPER LEVEL LOW WILL RESIDE OVER EASTERN CANADA AND THE
EASTERN GREAT LAKES REGION EARLY IN THE PERIOD...BUT WILL SHIFT
EAST BY FRI/SAT...ALLOWING WEAK RIDGING TO DEVELOP OVER WI. A
LARGE CANADIAN SFC HIGH WILL RIDGE INTO THE WESTERN GREAT LAKES
DURING THIS PERIOD...BRINGING DRY...BUT CONTINUED COOL CONDITIONS.
WITH LOW-LEVEL WINDS TURNING NNE-NE...CONSIDERED THE POSSIBILITY
OF SOME LIGHT LAKE EFFECT SNOW SHOWERS OR FLURRIES IN EASTERN WI...
BUT WINDS ARE VERY LIGHT ON FRIDAY NIGHT...AND MOISTURE AND
INSTABILITY ARE NOT VERY FAVORABLE ON SATURDAY...SO KEPT A DRY
FCST INTACT.
THE UPPER PATTERN WILL TRANSITION BACK TO A BROAD UPPER TROF LATE
IN THE WEEKEND...AND CONTINUING THROUGH THE MIDDLE OF NEXT WEEK.
THE ONLY SIGNIFICANT STORM OF THE WEEK IS A LOW PRESSURE SYSTEM
WHICH MOVES THROUGH THE SOUTHERN PLAINS ON SATURDAY...THEN LIFTS
NE THROUGH THE TENNESSEE VALLEY AND INTO THE MID-ATLANTIC STATES
BY MONDAY. THIS STORM SHOULD PASS FAR ENOUGH SOUTH AND EAST OF THE
REGION TO PREVENT ANY SIGNIFICANT PCPN DEVELOPMENT OVER C/NE WI.
HOWEVER...LOW-LEVEL CYCLONIC FLOW AND THE PRESENCE OF THE BROAD
UPPER TROF COULD BRING SCT LIGHT SNOW SHOWERS OR FLURRIES AT
TIMES. FOR NOW...WILL MAINLY BE CARRYING SLIGHT CHC POPS FROM THE
LATE WEEKEND THROUGH MIDWEEK.
H8 TEMPS WILL NOT VARY MUCH OVER THE PERIOD...WITH MOST OF THE
MEDIUM RANGE MODELS FORECASTING -8 TO -12 C. THIS SHOULD CONTINUE
THE TREND OF BELOW NORMAL TEMPERATURES FOR THE NEXT WEEK...WITH
LOWS IN THE TEENS AND LOWER 20S...AND HIGHS IN THE 30S.
&&
.AVIATION...3000 TO 4000 FT CIGS ACROSS NORTHERN WISCONSIN MUCH
OF THE NIGHT WITH SCATTERED SNOW SHOWERS AT D25/LNL/EGV/ARV. VFR
WITH LESS CLOUDS OVER CENTRAL AND EAST CENTRAL WISCONSIN. MAINLY
VFR CONDITIONS THURSDAY WITH JUST A FEW SNOW FLURRIES POSSIBLE IN
THE AFTERNOON.
RDM
&&
.GRB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS GREEN BAY WI
644 PM CDT WED MAR 20 2013
UPDATED AVIATION PORTION FOR 00Z TAF ISSUANCE
.SHORT TERM...TONIGHT AND THURSDAY.
LATEST RUC ANALYSIS AND SATELLITE/RADAR IMAGERY SHOW A BROAD AND
ELONGATED UPPER LEVEL LOW PRESSURE SYSTEM SPINNING FROM THE CENTRAL
GREAT LAKES TO NEW ENGLAND EARLY THIS AFTERNOON. CLOUDS HAVE BEEN
SPREADING SOUTH ACROSS THE UPPER PENINSULA AND NORTHERN WISCONSIN SO
FAR TODAY...AS A RESULT OF SHORTWAVE LOBES ROTATING AROUND THE
PARENT VORTEX...AND ALSO STEEPENING LOW LEVEL LAPSE RATES. THESE
CONDITIONS ALSO PROMOTE CONDITIONS FOR SIGNIFICANT LAKE EFFECT
SNOWS...WHICH ARE OCCURRING WITHIN THE SNOW BELTS OF THE WESTERN
UPPER PENINSULA. IN FACT...IRONWOOD HAS OSCILLATED BETWEEN 1/2SM
AND 3/4SM FOR MUCH OF THE DAY. LAKE EFFECT POTENTIAL IS THE MAIN
FORECAST CONCERN OVER THE NEXT 24 HOURS AS WIND TRAJECTORIES BECOME
MORE FAVORABLE FOR N-C WISCONSIN.
TONIGHT...SHORTWAVE TROUGH WILL DIVE SOUTH ACROSS CENTRAL AND
SOUTHERN WISCONSIN THIS EVENING...ON THE WESTERN FLANK OF THE UPPER
LOW. NOT SOLD THAT PRECIP WILL TURN OFF AT SUNSET...THOUGH DIURNAL
INSTABILITY WILL BE LOST. WILL KEEP LIGHT SNOW SHOWERS AND FLURRIES
GOING FOR A GOOD CHUNK OF THE EVENING. BEHIND THE SHORTWAVE...LOW
LEVEL WINDS TURN TO THE NNW. WIND TRAJECTORIES LOOK REALLY GOOD FOR
A SOLID LAKE EFFECT EVENT FOR N-C WISCONSIN. THERMAL PROFILES ARE
ALSO IN THE OPTIMAL DENDRITIC GROWTH ZONE THROUGH THE NIGHT...AND
THERE IS SUFFICIENT MOISTURE IN THE 850-700MB LAYER AS WELL. ON THE
MINUS SIDE...SUBSIDENCE WILL BE INCREASING THROUGH THE NIGHT AND
LAKE INDUCED CAPE WILL GRADUALLY DIMINISH. THE LOCAL LAKE EFFECT
PARAMETER DOES SHOW A SLIGHT DIMINISHING TREND TONIGHT...BUT NOT
THAT SIGNIFICANT. A LIMITING FACTOR MAY BE THE 15 KT BL WINDS...IN
WHICH THE NORTHERN PART OF VILAS COUNTY GETS ADVISORY CRITERIA
SNOW...AND THE SOUTHERN HALF DOES NOT. SO THINK WILL GO WITHOUT AN
ADVISORY AND ISSUE AN SPS FOR THE COUNTY TONIGHT...AND WILL
HIGHLIGHT THAT SEVERAL INCHES OF SNOW ARE POSSIBLE ACROSS THE
NORTHERN PART OF THE COUNTY. PARTIAL CLEARING SHOULD OCCUR OUTSIDE
THE LAKE EFFECT BELT DURING THE OVERNIGHT HOURS...BUT DO NOT THINK
WILL SEE DECOUPLING. AS A RESULT...LOW TEMPS WILL BE COMPARABLE TO
LAST NIGHTS LOWS.
THURSDAY...LAKE EFFECT SNOW SHOWERS WILL CONTINUE OVER N-C WISCONSIN
THROUGH EARLY AFTERNOON...BUT SHOULD DIMINISH AS DRY AIR INVADES
FROM THE NORTH. ELSEWHERE...AFTER A MOSTLY CLEAR TO PARTLY CLOUDY
START TO THE DAY...CLOUDS SHOULD BE INCREASING BY LATE MORNING OR
EARLY AFTERNOON AS WILL STILL HAVE PLENTY OF LOW LEVEL MOISTURE AND
STEEP LOW LEVEL LAPSE RATES AROUND. INCREASED CLOUD COVER...BUT
KEPT THE SNOW CHANCES CONFINED TO THE SNOW BELT. HIGHS SEVERAL
DEGREES WARMER THAN TODAY WITH HIGHS MAINLY IN THE MID TO UPPER 20S.
.LONG TERM...THURSDAY NIGHT THROUGH NEXT WEDNESDAY...MAIN FCST
CONCERN IS TEMPERATURES.
A LARGE UPPER LEVEL LOW WILL RESIDE OVER EASTERN CANADA AND THE
EASTERN GREAT LAKES REGION EARLY IN THE PERIOD...BUT WILL SHIFT
EAST BY FRI/SAT...ALLOWING WEAK RIDGING TO DEVELOP OVER WI. A
LARGE CANADIAN SFC HIGH WILL RIDGE INTO THE WESTERN GREAT LAKES
DURING THIS PERIOD...BRINGING DRY...BUT CONTINUED COOL CONDITIONS.
WITH LOW-LEVEL WINDS TURNING NNE-NE...CONSIDERED THE POSSIBILITY
OF SOME LIGHT LAKE EFFECT SNOW SHOWERS OR FLURRIES IN EASTERN WI...
BUT WINDS ARE VERY LIGHT ON FRIDAY NIGHT...AND MOISTURE AND
INSTABILITY ARE NOT VERY FAVORABLE ON SATURDAY...SO KEPT A DRY
FCST INTACT.
THE UPPER PATTERN WILL TRANSITION BACK TO A BROAD UPPER TROF LATE
IN THE WEEKEND...AND CONTINUING THROUGH THE MIDDLE OF NEXT WEEK.
THE ONLY SIGNIFICANT STORM OF THE WEEK IS A LOW PRESSURE SYSTEM
WHICH MOVES THROUGH THE SOUTHERN PLAINS ON SATURDAY...THEN LIFTS
NE THROUGH THE TENNESSEE VALLEY AND INTO THE MID-ATLANTIC STATES
BY MONDAY. THIS STORM SHOULD PASS FAR ENOUGH SOUTH AND EAST OF THE
REGION TO PREVENT ANY SIGNIFICANT PCPN DEVELOPMENT OVER C/NE WI.
HOWEVER...LOW-LEVEL CYCLONIC FLOW AND THE PRESENCE OF THE BROAD
UPPER TROF COULD BRING SCT LIGHT SNOW SHOWERS OR FLURRIES AT
TIMES. FOR NOW...WILL MAINLY BE CARRYING SLIGHT CHC POPS FROM THE
LATE WEEKEND THROUGH MIDWEEK.
H8 TEMPS WILL NOT VARY MUCH OVER THE PERIOD...WITH MOST OF THE
MEDIUM RANGE MODELS FORECASTING -8 TO -12 C. THIS SHOULD CONTINUE
THE TREND OF BELOW NORMAL TEMPERATURES FOR THE NEXT WEEK...WITH
LOWS IN THE TEENS AND LOWER 20S...AND HIGHS IN THE 30S.
&&
.AVIATION...3000 TO 4000 FT CIGS ACROSS NORTHERN WISCONSIN MUCH OF
THE NIGHT WITH SCATTERED SNOW SHOWERS AT D25/LNL/EGV/ARV. VFR WITH
LESS CLOUDS OVER CENTRAL AND EAST CENTRAL WISCONSIN. MAINLY VFR
CONDITIONS THURSDAY WITH JUST A FEW SNOW FLURRIES POSSIBLE IN THE
AFTERNOON.
RDM
&&
.GRB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS GREEN BAY WI
224 PM CDT TUE MAR 19 2013
.SHORT TERM...
LATEST RUC ANALYSIS AND SATELLITE/RADAR IMAGERY SHOW A VERTICALLY
STACKED LOW PRESSURE SYSTEM STALLED OVER FAR EASTERN LAKE SUPERIOR
THIS AFTERNOON. CLEARING SKIES ARE GRADUALLY OCCURRING FROM SW TO
NE ACROSS THE STATE AND HAS NOW REACHED FROM ABOUT RHINELANDER TO
MANITOWOC. STILL GETTING AN OCCASIONAL LIGHT SNOW OR FLURRY REPORT
OVER N-C WISCONSIN...AND VSBYS ARE ALSO OCCASIONALLY FALLING TO
AROUND 4SM DUE TO BLOWING SNOW. WIND GUSTS HAVE BEHAVED THEMSELVES
SO FAR THIS AFTERNOON...AS PEAK GUSTS WITHIN THE FORECAST AREA HAVE
REMAINED BELOW 35 KTS. SHEBOYGAN SEEMS TO BE THE LONE SPOT WHERE
GUSTS HAVE REACHED GREATER THAN 40 MPH. AS THE UPPER LOW REMAINS
STATIONARY TONIGHT AND DROPS SOUTH TOMORROW...SNOW CHANCES AND CLOUD
COVER ARE THE MAIN FORECAST CONCERNS.
TONIGHT...UPPER LEVEL LOW PRESSURE TO SIT AND SPIN OVER EASTERN LAKE
SUPERIOR TONIGHT. INCOMING LOW LEVEL DRYING FROM THE SW HAS
POTENTIAL TO REACH THE U.P. BORDER WHERE WNW WINDS SHOULD KEEP
CLOUDS ALONG AND NORTH OF THE BORDER THROUGH THE EVENING. AS A
RESULT...WENT MUCH MORE OPTIMISTIC WITH CLOUD COVER THIS EVENING
WITH MOSTLY CLEAR TO PARTLY CLOUDY CONDITIONS ACROSS THE MAJORITY OF
THE FORECAST AREA EXPECT FOR NEAR THE BORDER. AFTER MIDNIGHT...MID
AND UPPER MOISTURE PIVOT AROUND THE UPPER LOW AND BACK SOUTH ACROSS
NORTHERN WISCONSIN. THINK CLOUDS WILL INCREASE ONCE AGAIN WITH SNOW
SHOWERS RETURNING TO NORTH-CENTRAL WISCONSIN. NOT EXPECTING MUCH
MORE THAN A HALF INCH ACCUM THOUGH. COLD ADVECTION WILL OCCUR
THROUGH THE NIGHT AND LOWS UPSTREAM WERE IN THE SINGLE DIGITS ABOVE
ZERO OVER EASTERN MINNESOTA. THAT SOUNDS ABOUT RIGHT FOR LOWS
TONIGHT...SINCE BL WINDS LOOK TO BE TOO STRONG FOR DECOUPLING. SO
RAISED LOWS A DEGREE OR TWO.
WEDNESDAY...MOISTURE WILL CONTINUE TO SURGE SOUTH ACROSS CENTRAL AND
SOUTHERN WISCONSIN WEDNESDAY MORNING. WITH STEEPENING LOW LEVEL
LAPSE RATES...SKIES SHOULD CLOUD UP PRETTY QUICKLY BY MID TO LATE
MORNING. LIGHT SNOW SHOWERS AND FLURRIES SHOULD BE SPREADING FROM
NORTH TO SOUTH FROM LATE MORNING THROUGH THE AFTERNOON HOURS...WHEN
THE SHORTWAVE THAT CREATED THE SNOW YESTERDAY...ROTATES AROUND THE
BACKSIDE OF THE UPPER LOW AND DROPS SOUTH ACROSS THE STATE. LOW
LEVEL WINDS DO VEER TO THE NW TOMORROW AFTERNOON WHICH WILL BE
BETTER FOR LAKE ENHANCEMENT. SO WILL GIVE POPS A BOOST TOMORROW
EVERYWHERE. POTENTIAL WILL BE THERE FOR A HALF TO AN INCH OF NEW
SNOW ACROSS THE AREA.
.LONG TERM...
SOME HINTS THAT CURRENT COLD PATTERN MAY WANE TOWARDS END OF MODEL
RUN AS BLOCKY PATTERN BREAKS DOWN...THOUGH BEFORE THAT DRY WITH
BELOW NORMAL TEMPERATURES CONTINUE.
WED NIGHT THROUGH THU...INFLUENCE OF UPPER LOW OVER THE EASTERN
LAKES TO LESSEN WITH RIDGE MOVING IN. THOUGH WITH CYCLONIC FLOW
HAVE STAYED WITH HIGHER CLOUD COVER ON WED NIGHT...PARTLY CLOUDY
BY THU. WINDS EXPECTED TO BE LIGHTER BUT NOT DECOUPLE
TOTALLY...ESPECIALLY EAST. WITH THESE THOUGHTS...RAISED TEMPS A
BIT WITH COLDEST SPOT EXPECTED OVER CENTRAL WHERE WINDS WILL BE LIGHTEST.
WITH WINDS SHIFTING NORTH AFTER PASSAGE OF SHORT WAVE EXPECT LAKE
EFFECT SHOWERS TO CONTINUE...THOUGH AS RIDGE BUILDS IN INVERSION
HEIGHTS LOWER AND DRIER AIR WORKS IN. HAVE TRENDED DOWN ON
POPS...ESPECIALLY AFTER MIDNIGHT WED NIGHT.
THU NIGHT ONWARD...AIR MASS TRENDING TO MODERATE WITH
TIME...THOUGH NO APPEARANCE OF ANY SIG WAA. WILL SLOWLY BRING
TEMPS UP...THOUGH STILL HAVE HIGHS SOME 5 TO 10 DEGREES BELOW
NORMS. PACIFIC SYSTEM TO DROP SE INTO SOUTHERN PLAINS...THEN LIFT
OUT INTO THE OHIO VALLEY MONDAY TIMEFRAME. SOME DIFFERENCES IN
THE MODELS WITH GFS STRONGER AND FURTHER NORTH BRINGING QPF NORTH
INTO THE REGION. HAVE DOWN PLAYED THAT SCENARIO IN GRIDS...AS GFS
LACK CONSISTENCY IN LATTER PERIODS. HAVE TRENDED TOWARDS ECENS.
CANADIAN HIGH PRESSURE TO DOMINATE AT THE SURFACE WITH WINDS
SHIFTING NE SAT INTO TUE. HAVE BROUGHT CLOUDS UP SLIGHTLY IN THE
EAST WITH FLOW OFF LAKE...THOUGH WITH LIMITED INSTABILITY WILL
STAY DRY.
&&
.AVIATION...MAINLY MVFR CIGS AND VSBYS WITH SCATTERED SNOW
SHOWERS TO PERSIST THIS MORNING. SNOW SHOWERS AND BLOWING SNOW
WITH STRONG WEST WINDS WILL PRODUCE IFR VSBYS AT TIMES THIS
MORNING WITH THE FRESH SNOW. AS THE SYSTEM SHIFTS EAST LATER
TODAY...CONDITIONS TO IMPROVE TO MVFR CIGS AND VFR VSBYS
WITH SOME DECREASE IN THE SUSTAINED WEST WIND SPEED BY EARLY THIS
EVENING. SURFACE WIND GUSTS TO 25 MPH MAY LINGER OVER NORTHEAST
WISCONSIN THROUGH WEDNESDAY.
&&
.GRB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
MPC/TE
AREA FORECAST DISCUSSION
NWS GREEN BAY WI
1220 AM CDT TUE MAR 19 2013
UPDATED AVIATION PORTION FOR 06Z TAF ISSUANCE
.UPDATE...DECIDED TO EXTEND THE WINTER WEATHER ADVISORY UNTIL 10
O`CLOCK TUESDAY FOR AREA SOUTH OF HIGHWAY 29 AND ALSO FOR DOOR
COUNTY AS MODELS FORECAST 40 KNOT WINDS AT 925 MPH LATER TONIGHT
AND TUESDAY MORNING WITH STRONG COLD ADVECTION AND FRESH SNOW ON
THE GROUND. CONSIDERABLE BLOWING AND DRIFTING SNOW POSSIBLE ON
NORTH SOUTH ROADS IN RURAL AREAS. WOULD NOT BE SURPRISED TO HAVE
SOME ROADS CLOSED WHERE DRIFTS ARE USUALLY A PROBLEM. DID NOT
INCLUDE THE AREAS FURTHER NORTH AS THE GRADIENT IS WEAKER AND THAT
REGION IS MOSTLY WOODED WHICH SLOWS DOWN THE WIND.
RDM
&&
.PREV DISCUSSION...ISSUED AT 719 PM CDT MON MAR 18 2013...
SHORT TERM...
LATEST RUC ANALYSIS AND SATELLITE/RADAR IMAGERY SHOW A STRONG
SHORTWAVE MOVING ACROSS THE NORTHERN MISSISSIPPI VALLEY EARLY THIS
AFTERNOON. AHEAD OF THIS TROUGH...A SHORTWAVE IMPULSE LIFTED
NORTH OVER SOUTHEAST WISCONSIN THIS MORNING AND ACROSS NORTHEAST
WISCONSIN THIS AFTERNOON. THIS IMPULSE HAS GENERATED WIDESPREAD
1/4SM TO 1/2SM ACROSS THE FOX VALLEY AND LAKESHORE. THE MAIN BAND
OF SNOW RIGHT AHEAD OF THE MAIN SHORTWAVE IS MOVING ACROSS CENTRAL
WISCONSIN WHERE MODERATE TO HEAVY SNOW IS ALSO OCCURRING. JUST
LEARNED ABOUT HWY 13 FROM WISCONSIN RAPIDS TO THE DELLS THAT TRAVEL
BECOMING NOT ADVISED. THOUGHT ABOUT EXPANDING THE ADVISORY ACROSS
THE REST OF THE AREA...BUT WEBCAMS FROM OSHKOSH SHOW LITTLE IN THE
WAY OF ACCUMULATIONS ON THEIR ROADWAYS. ROAD TEMPERATURES ARE A
COUPLE DEGREES WARMER THERE THAN FARTHER NORTH AND WEST...WHICH
COULD EXPLAIN PART OF THE ACCUMULATION DIFFERENCES. WITH THE BACK
EDGE OF THE HEAVIER SNOW NOT TOO FAR AWAY FROM THE SOUTHERN FOX
VALLEY...WILL KEEP THEM OUT OF THE ADVISORY. ROADS ARE BECOMING
SNOW COVERED IF NOT ALREADY SNOW COVERED FARTHER NORTH...SO WILL LET
THE ADVISORY GO AS PLANNED. WILL BUMP UP ACCUMS A BIT OVER NE
WISCONSIN. THE EVENING CREW MAY BE ABLE TO CANCEL THE ADVISORY
EARLY IF THE STRENGTHENING WINDS THIS EVENING DO NOT CREATE BLOWING
AND DRIFTING SNOW OF ANY SIGNIFICANCE.
TONIGHT...SHORTWAVE TROUGH WILL SWING NE ACROSS NORTHEAST WISCONSIN
THIS EVENING...AS ITS PARENT TROUGH CLOSES OFF OVER THE UPPER
PENINSULA AND LAKE SUPERIOR. THE LATEST HRRR SUGGESTS MOST OF THE
SYNOPTIC SNOW WILL HAVE PEELED OUT BY THE START OF THE
PERIOD...EXCEPT OVER NORTH-CENTRAL WISCONSIN WHERE DEEP MOISTURE
WILL HANG IN PLACE. WHERE THE UPPER AND MID-LEVEL MOISTURE DOES
DEPART...SNOW WILL DIMINISH TO FLURRIES OR PATCHY LIGHT FREEZING
DRIZZLE. WILL KEEP FZDZ WORDING AS CHANCE SINCE OBS UPSTREAM SEEM
WIDELY SCT...BUT POTENTIAL WILL BE THERE FOR A FEW HOURS.
WRAP-AROUND SNOW THEN TO RETURN LATE IN THE EVENING AND OVERNIGHT.
PLENTY OF LOW VSBYS IN SNOW SHOWERS OVER SOUTHERN MINNESOTA AND
EASTERN SD...SO DO NOT FEEL COMFORTABLE GOING JUST FLURRIES THOUGH
ACCUMS SHOULD ONLY BE A TENTH TO A HALF INCH. MEANWHILE...ARCTIC AIR
WILL BE PUNCHING ACROSS CENTRAL AND SOUTHERN WISCONSIN DURING THE
EVENING...AND INTO NORTHEAST WISCONSIN OVERNIGHT. AS THIS COLDER
AIR ARRIVES...WEST WEST WILL BE STRENGTHENING AND BECOME QUITE
GUSTY. THE BEST PRESSURE RISES WILL SPLIT THE AREA TO THE NORTH AND
SOUTH...BUT SOME GUSTS COULD STILL REACH 35 MPH. UPSTREAM OFFICES
CANCELLED THEIR BLIZZARD WARNINGS EARLY SINCE VSBYS WERE NOT LOW
ENOUGH...SUGGESTING BLOWING AND DRIFTING MAY NOT HAVE BEEN AS BIG A
FACTOR AS PREVIOUSLY THOUGHT. EARLY INDICATIONS OF SNOWFALL RATIOS
SO FAR TODAY ARE AROUND 10-12 TO 1...SO SNOW MAY BE TOO WET TO RESTRICT
VSBYS DUE TO BLOWING. WILL KEEP THE END TIME OF THE ADVISORY AT
03Z.
MONDAY...THE UPPER LOW WILL SHIFT A LITTLE NE OVER LAKE SUPERIOR
TOMORROW...TAKING SOME OF THE DEEPER MOISTURE WITH IT. SHOULD STILL
BE ENOUGH MOISTURE AND CYCLONIC FLOW ALOFT FOR OCCASIONAL SNOW
SHOWERS AND FLURRIES DURING THE MORNING...THEN BECOMING CONFINED TO
N-C WISCONSIN DURING THE AFTERNOON. WEST TO NORTHWEST WINDS WILL
REMAIN GUSTY...AND AN ISOLATED GUST UP TO 40 MPH WILL BE POSSIBLE IN
THE OPEN AREAS. TEMPS MAINLY IN THE MIDDLE 20S.
LONG TERM...
LITTLE CHANGE IN THE OVERALL...COLD...PATTERN FOR THE REGION
THROUGH THIS PERIOD. BROAD UPPER TROF OVER EASTERN TWO THIRDS OF
U.S. UPPER LOW TO SPIN OVER EASTERN LAKES INTO FRI...WHILE
MAIN STORM TRACK AND MOISTURE REMAINS TO OUR SOUTH. AT THE SURFACE
CANADIAN HIGH PRESSURE TO REMAIN OVER THE REGION.
TUE NIGHT INTO THU...
MAIN ISSUES LAKE EFFECT CHANCES AND CHANCE FOR SNOW SHOWERS ON
WED. PIECES OF ENERGY WILL CIRCULATE AROUND THE LOW THIS
PERIOD...BRINGING THREAT OF SNOW SHOWERS...FLURRIES. BEST CHANCE
TO BE ON WED AS UPPER TROF DROPS SOUTH OVER THE STATE.
HAVE TRIED TO ADD DEFINITION TO LAKE EFFECT CHANCES...WITH HIGHEST
CHANCES LATE TUE NIGHT INTO WEDNESDAY NIGHT AS HAVE SOME SYNOPTIC
LIFT AND MOISTURE. BY THE TIME THE WINDS BECOME MORE FAVORABLE
LATER WED NIGHT AND THU...SOUNDINGS SHOW LOWERING INVERSION
HEIGHTS AND DRYING WORKING IN.
THU NIGHT ONWARD...
EXTENDED MODELS STILL HAVING ISSUES LATER PERIODS...BRINGING LIGHT
QPF INTO THE REGION. STILL EXPECT ANY PACIFIC SYSTEM TO DIVE SE
AND PASS TOO FAR TO OUR SOUTH TO BRING ORGANIZED PCPN TO NE WI.
WITH HIGH PRESSURE AT SURFACE THROUGH PERIOD AND LIMITED MOISTURE
HAVE STAYED WITH DRY FORECAST. LLVL WINDS SHIFT TO NE FOR BRIEF
PERIOD SAT...WITH THOUGHTS OF LES OFF LAKE MICHIGAN. THOUGH AGAIN MOISTURE
AND INSTABILITY LIMITED. BELOW NORMAL TEMPERATURES EXPECTED TO
CONTINUE INTO THE LAST WEEK OF MARCH. HAVE AGAIN DROPPED FEW
DEGREES OFF GUIDANCE TEMPS FOR LATTER PERIODS.
&&
.AVIATION...MAINLY MVFR CIGS AND VSBYS WITH SCATTERED SNOW SHOWERS
TO PERSIST THIS MORNING. SNOW SHOWERS AND BLOWING SNOW WITH STRONG
WEST WINDS WILL PRODUCE IFR VSBYS AT TIMES THIS MORNING WITH THE
FRESH SNOW. AS THE SYSTEM SHIFTS EAST LATER TODAY...CONDITIONS TO
IMPROVE TO VFR LEVELS ALONG WITH SOME DECREASE IN THE SUSTAINED WEST
WIND SPEED. SURFACE WIND GUSTS TO 25 MPH MAY LINGER OVER NORTHEAST
WISCONSIN THROUGH WEDNESDAY.
TDH
&&
.GRB WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY UNTIL 10 AM CDT THIS MORNING FOR WIZ022-
030-031-035>040-045-048>050-074.
WINTER WEATHER ADVISORY UNTIL 1 AM CDT EARLY THIS MORNING FOR
WIZ005-010>013-018>021-073.
&&
$$
AREA FORECAST DISCUSSION
NWS ALBANY NY
352 AM EDT THU MAR 21 2013
.SYNOPSIS...
LAKE EFFECT SNOW WILL BEGIN TO WIND DOWN ACROSS THE
WESTERN ADIRONDACKS THIS MORNING...ALTHOUGH IT WILL REMAIN CHILLY
TODAY AS AN UPPER LEVEL TROUGH CONTINUES TO BE SITUATED OVER THE
AREA. SOME SNOW SHOWERS AND FLURRIES WILL BE POSSIBLE TONIGHT INTO
FRIDAY...MAINLY ACROSS NORTHERN AND HIGH TERRAIN AREAS. TEMPERATURES
OVER THE WEEKEND WILL BEGIN TO MODERATE WITH INCREASING AMOUNTS OF
SUNSHINE...BUT TEMPERATURES WILL CONTINUE TO AVERAGE BELOW NORMAL.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
AS OF 352 AM EDT...THE REGION REMAINS DOMINATED BY A LARGE CUTOFF
UPPER LEVEL TROUGH. THE TROUGH IS SITUATED FROM NORTHERN MAINE
SOUTHWESTWARD TOWARDS LOWER MICHIGAN. DURING THE DAY TODAY...THE
TROUGH AXIS WILL BEGIN TO SWING AROUND AND TOWARDS OUR AREA.
LAKE EFFECT SNOW CONTINUES TO IMPACT THE WESTERN ADIRONDACKS. OUR
00Z LOCAL HIRES WRF SIMULATION AND THE 03Z 3KM HRRR GUIDANCE BOTH
SHOW THE LAKE EFFECT SNOW BAND WEAKENING AND LIFTING NORTH OF OUR
AREA THIS MORNING...AS THE UPPER TROUGH AXIS BEGINS TO SHIFT...AND
THE LOW LEVEL FLOW BECOMES MORE SW WITH INCREASING SHEAR. WE WILL
ALLOW THE LAKE EFFECT SNOW WARNING TO EXPIRE AT 10Z. AN ADDITIONAL
INCH OR TWO MAY FALL BEFORE THE WARNING EXPIRES AND THE BAND
SHIFTS NORTH. SOME ADDITIONAL LIGHT ACCUMULATION IS POSSIBLE DURING
THE MORNING HOURS AFTER SUNRISE...BUT THIS LOOKS TO MAINLY OCCUR
IN UNINHABITED FORESTED AREAS TO THE NORTH OF STILLWATER RESERVOIR
AND OLD FORGE.
THE REMAINDER OF THE REGION WILL SEE A PARTLY TO MOSTLY CLOUDY
DAY. CLOUDS WILL BE MORE PREVALENT ACROSS THE ADIRONDACKS...AS
WELL AS ACROSS SOUTHEASTERN PARTS OF THE AREA...AS A WEAK COASTAL
WAVE DEVELOPS. A FEW FLURRIES ARE POSSIBLE ACROSS THE FAR
SOUTHEASTERN PARTS OF THE CWA THIS AFTN DUE TO THIS WEAK WAVE...BUT
NO ACCUM IS EXPECTED.
ELSEWHERE...IT LOOKS DRY THROUGH THE AFTN. IT WILL CONTINUE TO BE
QUITE CHILLY ACROSS THE REGION. WITH 850 HPA TEMPS OF -10 TO -14
DEGREES C...MAX TEMPS TODAY WILL STILL BE BELOW NORMAL...WITH
UPPER 20S TO UPPER 30S ACROSS THE AREA.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH SATURDAY NIGHT/...
AS THE TROUGH AXIS APPROACHES AND SWINGS THROUGH THE AREA...SOME
LIGHT SNOW SHOWERS ARE POSSIBLE FOR TONIGHT INTO FRIDAY...MAINLY
FOR NORTHERN/HIGH TERRAIN AREAS. WITH MOISTURE BEING LIMITED...QPF
WILL BE MEAGER...AND THE BEST SNOW ACCUMULATION WILL BE IN FAR
WESTERN AREAS...WHERE SOME LAKE MOISTURE WILL ALLOW FOR A LITTLE
LOCAL ENHANCEMENT AND UPSLOPE FLOW WILL ALLOW FOR MORE PERSISTENT
SNOW SHOWERS. WHILE THE HUDSON VALLEY AREA WILL SEE LITTLE TO NO
SNOW ACCUMULATION...A FEW INCHES ARE POSSIBLE ACROSS THE WESTERN
MOHAWK VALLEY AND ADIRONDACKS.
MIN TEMPS TONIGHT WILL BE CHILLY ONCE AGAIN WITH TEENS FOR MOST
AREAS. MAX TEMPS ON FRIDAY WILL CONTINUE TO BE SIMILAR TO
THURSDAY/S HIGHS...WITH 30S...AND 20S ACROSS THE HIGH TERRAIN.
THE CUTOFF WILL MAKE SOME EASTERN PROGRESS ON SATURDAY. WHILE
THERE STILL MAY BE SOME LINGERING SNOW SHOWERS ACROSS THE
ADIRONDACKS...THE REMAINDER OF THE AREA SHOULD BE DRY. TEMPS MAY
BE A FEW DEGREES WARMER...WITH MAX TEMPS RANGING FROM NEAR 30 IN
THE ADIRONDACKS TO THE LOWER TO MID 40S FOR THE HUDSON VALLEY AND
NW CT. IT MAY NOT FEEL TOO MUCH WARMER...HOWEVER...AS DECENT
MIXING WILL ALLOW FOR SOME GUSTY WINDS IN THE AFTN...WITH SOME
GUSTS OVER 25 MPH POSSIBLE.
DRY WEATHER IS FINALLY EXPECTED ACROSS THE ENTIRE REGION BY
SATURDAY NIGHT. MIN TEMPS LOOK TO RANGE FROM THE MID TEENS TO MID
20S.
&&
.LONG TERM /SUNDAY THROUGH WEDNESDAY/...
THE BIG QUESTION IN THE LONG TERM PERIOD REMAINS IS WHETHER OR NOT
FA IS IMPACTED BY THE LOW PRESSURE SYSTEM WHICH REDEVELOPS ALONG THE
MID ATLANTIC COAST ON MONDAY. THE GGEM HAS A MAINLY SNOW EVENT ACRS
FA STARTING LATE MONDAY AND CONTINUING THROUGH TUESDAY MORNING WHILE
THE GFS AND ECMWF JUST HAVE THE NORTHERN EDGE OF THE PCPN SHIELD
IMPACTING FAR SOUTHERN PTN OF FA LATE SUNDAY NIGHT INTO MONDAY
EVENING. THE GGEM IS SLOWEST AND GFS FASTEST WITH SFC LOW TRACK WITH
GGEM DEVELOPING DOUBLE BARREL SYSTEM BY MON AFT WHILE GFS AND ECMWF
TAKE SYSTEM OUT TO SEA. THIS IS A LOW CONFIDENCE FORECAST AND AT
THIS TIME HAVE GENERALLY GONE WITH HPC GUIDANCE AND HAVE CHANCE POPS
FOR THE PERIOD FROM LATE SUNDAY NIGHT INTO MONDAY NIGHT.
ON SUNDAY...EXPECT DRY CONDITIONS WITH TEMPS STILL BELOW NORMAL AND
INCREASING MID AND HIGH CLOUDS BY SUNDAY AFTERNOON. HIGHS ON
SUNDAY IN THE MID 30S TO MID 40S.
SUNDAY NIGHT THROUGH MONDAY NIGHT...INCREASE POPS FROM SOUTHWEST TO
NORTHEAST WITH CHANCE POPS SUNDAY NIGHT THROUGH MONDAY NIGHT EXCEPT
SLIGHT CHANCE POPS FAR NORTH. PARTIAL THICKNESS VALUES COLD ENOUGH
FOR A MAINLY SNOW EVENT PROVIDED SURFACE LOW TRACKS CLOSE ENOUGH.
EXPECT LOWS SUNDAY NIGHT UPPER TEENS TO LOWER 30S...HIGHS ON
MONDAY MID 30S TO LOWER 40S AND LOWS MONDAY NIGHT IN THE UPPER TEENS
TO AROUND 30.
TUESDAY THROUGH WEDNESDAY...EXPECT MAINLY DRY CONDITIONS AND
CONTINUED COOL WITH HIGHS BOTH DAYS MID 30S TO MID 40S AND LOWS
TUESDAY NIGHT IN THE UPPER TEENS TO AROUND 30.
&&
.AVIATION /08Z THURSDAY THROUGH MONDAY/...
A BROAD UPPER LEVEL TROUGH WILL CONTINUE TO IMPACT THE REGION THE
NEXT FEW DAYS. VFR CONDITIONS ARE EXPECTED TO PREVAIL THE NEXT 24
HOURS AT THE TAF SITES.
LAKE EFFECT SNOW SHOWERS ARE NOT EXPECTED TO IMPACT
KGFL/KALB/KPSF/KPOU THROUGH THIS EVENING. MAINLY CLEAR TO PARTLY
CLOUDY SKIES DURING THE REMAINDER OF TONIGHT WILL GIVE WAY TO
SCT-BKN STRATOCUMULUS FROM LATER THIS MORNING THROUGH THIS
AFTERNOON. A VCSH GROUP WAS ADDED TO KPSF.
MAINLY LIGHT AND VARIABLE WINDS DURING THE REMAINDER OF THE
OVERNIGHT WILL GIVE WAY TO W/NW AT 7-12 KTS TODAY...EXCEPT AT KGFL
WHERE THE WINDS WILL BE FROM SW TO W AT 10 KTS OR LESS. THE WINDS
WILL THEN DIMINISH THIS EVENING TO 3-5 KTS.
OUTLOOK...
THU NIGHT -FRI...MAINLY VFR.
SAT-SUN...VFR. NO SIG WX.
MON...VFR. CHC SUB-VFR IN SNOW OR RAIN SOUTH OF KALB.
&&
.FIRE WEATHER...
NO CRITICAL FIRE WEATHER CONCERNS FOR THE NEXT FIVE DAYS.
WIDESPREAD SNOWCOVER WILL BE IN PLACE OVER THE REGION THROUGH THE
REMAINDER OF THE WEEK.
A LINGERING UPPER LEVEL LOW WILL CONTINUE TO KEEP BELOW NORMAL
TEMPERATURES THROUGH THE WEEKEND. SOME ADDITIONAL SNOW SHOWERS AND
FLURRIES WILL OCCUR ACROSS NORTHERN AND HIGH TERRAIN AREAS THROUGH
SATURDAY.
&&
.HYDROLOGY...
NO HYDROLOGICAL PROBLEMS EXPECTED THROUGH THE WEEKEND.
A LINGERING UPPER LEVEL LOW WILL ALLOW FOR SNOW SHOWERS AND
FLURRIES...MAINLY ACROSS NORTHERN AND HIGH TERRAIN AREAS THROUGH
SATURDAY.
WHILE DAYTIME TEMPERATURES WILL RISE ABOVE FREEZING IN VALLEY
AREAS OVER THE NEXT FEW DAYS...TEMPS SHOULD DROP BELOW FREEZING AT
NIGHT. SLOW MELTING OF SNOW IS POSSIBLE OVER THE NEXT FEW
DAYS. RIVER AND STREAM LEVELS WILL MAINLY HOLD STEADY THROUGH THE
WEEKEND.
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...LAKE EFFECT SNOW WARNING UNTIL 6 AM EDT EARLY THIS MORNING FOR
NYZ032-033.
MA...NONE.
VT...NONE.
&&
$$
SYNOPSIS...FRUGIS
NEAR TERM...FRUGIS
SHORT TERM...FRUGIS
LONG TERM...11
AVIATION...11
FIRE WEATHER...FRUGIS
HYDROLOGY...FRUGIS
AREA FORECAST DISCUSSION
NWS DULUTH MN
329 AM CDT THU MAR 21 2013
.SHORT TERM...THROUGH FRIDAY.
A SHORTWAVE...WHICH IS AN EXTENSION OF THE LARGE EASTERN
CONUS/EASTERN CANADIAN UPPER TROUGH...WAS MOVING THROUGH THE
NORTHLAND AND SHOULD MOVE SOUTH AND EAST TODAY.
THERE CONTINUED TO BE SOME FLURRIES FALLING OUT OF A DECK OF CLOUDS
THAT COVERED PORTIONS OF NORTHEAST MINNESOTA AND NORTHERN
WISCONSIN...AND SOME LAKE EFFECT SNOW SHOWERS CONTINUED ALONG THE
SOUTH SHORE. CONDITIONS BECOME LESS FAVORABLE FOR LES TODAY...AS
850MB TEMPERATURES WARM THROUGH THE MORNING WITH DRIER AIR MOVING
OVER LAKE SUPERIOR. WE DON`T EXPECT MUCH ACCUMULATION THIS MORNING
OVER THE SNOWBELT REGION. CLOUD COVER WILL BE A CHALLENGE TODAY. THE
WESTERN EDGE OF THE CLOUDS THIS MORNING WAS MOVING SLOWLY EAST AND
THE CLOUDS APPEAR TO BE DIMINISHING. HOWEVER...THE RAP SUGGESTS
WE`LL SEE SOME REDEVELOPMENT BY LATE MORNING/EARLY AFTERNOON WITH
SOME HEATING. WE DID FOLLOW THAT TREND...AND HAVE PARTLY TO MOSTLY
CLOUDY SKIES GOING FOR ABOUT THE SOUTHERN HALF TO TWO THIRDS OF THE
CWA THROUGH MID AFTERNOON. WE EXPECT HIGHS TODAY TO BE MAINLY IN THE
MID TWENTIES...BUT WILL HAVE TO ADJUST A FEW DEGREES DEPENDING ON
THE EXTENT OF THE CLOUD COVER.
TONIGHT INTO FRIDAY THE NORTHLAND GETS SQUEEZED BETWEEN TWO
TROUGHS...ONE EXTENDING FROM NORTHERN BRITISH COLUMBIA INTO THE
NORTHERN PLAINS...AND THE PERSISTENT EASTERN TROUGH. WE EXPECT
TONIGHT TO BE CLEAR TO PARTLY CLOUDY FOR MOST AREAS WITH LIGHTER
WINDS. WE WENT BELOW MOST OF THE LOW TEMP GUIDANCE TONIGHT...CLOSER
TO THE NHGEMBC. DEEP SNOWPACK...LIGHT WINDS AND MINIMAL CLOUD COVER
SHOULD ALLOW FOR THE COLD TEMPS. THICKER CLOUDS WILL MOVE INTO THE
ARROWHEAD/BORDER REGION LATER TONIGHT...AND THAT WILL KEEP THEM FROM
REALLY GETTING COLD.
FRIDAY WILL BE PARTLY SUNNY WITH HIGHS A BIT WARMER...FROM 28 TO 34
FOR MOST AREAS.
.LONG TERM...FRIDAY NIGHT THROUGH THURSDAY.
THE WESTERN LAKE SUPERIOR REGION WILL SITUATED BETWEEN A LARGE CUT
OFF LOW ROTATING OVER THE NEW ENGLAND STATES...AND A DIGGING TROUGH
OVER THE ROCKIES THROUGH THE WEEKEND. THIS WILL RESULT IN WEAK SFC
RIDGING OVER THE CWA FRIDAY NIGHT/SAT. A NORTH TO NORTHEAST FLOW
WILL DEVELOP SAT NIGHT THROUGH SUNDAY AS A VORT MAX WITH SFC
REFLECTION LOW EJECTS OUT OF THE BASE OF THE TROUGH AND TRACKS EAST
ACROSS THE SRN PLAINS. AT THIS TIME...MODELS IN AGREEMENT THAT THE
NRN EXTENT OF ANY PRECIPITATION ASSOCIATED WITH THE WAVE TRANSLATES
ALONG THE SOUTHERN MN/WI STATE LINES. MEANWHILE...AN ELONGATED VORT
MAX BREAKS FREE FROM THE EASTERN LOW...AND RETROGRADES ACROSS
ONTARIO FRIDAY NIGHT...DROPPING INTO THE NRN LAKE SUPERIOR/MN
ARROWHEAD REGION SATURDAY. ATTM...THIS VORT IS EXPECTED TO BRING
PRIMARILY INCREASING CLOUDS. HOWEVER...RH FIELDS AND LATEST NAM BUFR
SOUNDINGS SHOWS INCREASING LOW LEVEL MOISTURE FRI NIGHT THAT
SUGGESTS A SMALL POTENTIAL FOR SOME FOG/BR OR POSSIBLY VERY LIGHT
DZ/SN SAT/SAT NIGHT. HOWEVER...HAVE KEPT FCST DRY THROUGH THE
WEEKEND AS ANY THE PRECIP CHCS ARE VERY SMALL AND QPF WILL BE
ISOLATED AND LIGHT.
BEYOND THE WEEKEND...THE H50 FLOW BECOMES VERY DISORGANIZED AS
MODELS TRY TO RESOLVE PHASING THE DOUBLE LOWS OVER THE ERN COAST.
GENIALLY HAVE KEPT EXTENDED DRY WITH TEMPERATURES NEAR TO A FEW
DEGREES BELOW NORMAL.
&&
.AVIATION...06Z TAF ISSUANCE.
OVERCAST SKIES AROUND 3 KFT WITH PERIODS OF HIGHER END MVFR CIGS
AROUND 2 KFT WILL SPREAD SOUTH ACROSS THE EASTERN HALF OF THE
REGION THROUGH THE NIGHT. CIGS ARE EXPECTED TO REMAIN VFR OVER
NORTH CENTRAL MINNESOTA...INCLUDING THE KINL AND KBRD TERMINALS.
VFR CIGS WILL PREVAIL AFTER 15Z THROUGH THE END OF THE TAF PERIOD.
&&
.POINT TEMPS/POPS...
DLH 26 -1 31 13 / 10 0 10 10
INL 25 -8 30 9 / 0 0 10 10
BRD 25 -2 32 15 / 10 0 10 10
HYR 27 -5 33 11 / 10 0 10 10
ASX 26 3 31 13 / 10 10 10 10
&&
.DLH WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
&&
$$
SHORT TERM...MELDE
LONG TERM....GRANING
AVIATION...CANNON
AREA FORECAST DISCUSSION
NWS OMAHA/VALLEY NE
337 AM CDT THU MAR 21 2013
.DISCUSSION...
FORECAST CHALLENGES FOR THIS FORECAST PACKAGE WILL INCLUDE TIMING
OF THE SNOW CHANCES TODAY...TONIGHT AND FRIDAY...SATURDAY INTO THE
EXTENDED...WILL IT BE MEASURABLE AND HOW MUCH?...WILL THERE BE
ANY PERIODS OF A MIX?...ALSO TEMPERATURES THROUGH THE PERIOD.
OUR OAX SOUNDING FROM 00Z WAS QUITE DRY WITH SOME HIGHER RH AT H5
AND H85...BUT ONLY 36 PERCENT OF NORMAL PRECIPITABLE WATER. THIS
WAS COMMON ACROSS THE ENTIRE MIDWEST...WITH THE CLOSEST NEAR NORMAL
PRECIPITABLE WATER AT RAPID CITY AND DODGE CITY.
A LOOP OF THE IR SATELLITE IMAGERY SHOWS A LOT GOING ON AND
DIFFERENT FLOWS ACROSS THE COUNTRY. THERE IS A STRONG AREA OF LOW
PRESSURE/WINTER SYSTEM OVER THE NORTHEAST U.S./GREAT LAKES. THE
TROF IN THE PACIFIC NORTHWEST SHOWS UP...AS WELL AS THE FETCH OF
TROPICAL MOISTURE FROM THE PACIFIC ACROSS THE SOUTHERN PLAINS. AT
H85...THE THERMAL GRADIENT SHOWS UP NICELY BETWEEN THE COLD SYSTEM
OFF TO OUR EAST...AND THE WARMER AIR WITH THE PACIFIC SYSTEM THAT
WILL AFFECT US INTO THE WEEKEND WITH -12 DEG C AT OMA AND +1C AT
LBF. AT THE SURFACE....SURFACE HIGH PRESSURE EXTENDED FROM THE
NORTHERN PLAINS THRU THE MISSOURI RIVER VALLEY INTO IOWA AND
MISSOURI. LOCALLY TEMPERATURES WERE IN THE TEENS AND 20S WITH
DEWPOINTS IN THE SINGLE DIGITS AND TEENS. AN AREA OF LOW PRESSURE
EXTENDED FROM WYOMING THROUGH COLORADO. TEMPERATURES WERE MUCH
WARMER IN WESTERN NEBRASKA WITH 30S AND 40S. AT 08Z...A NORTHWEST
TO SOUTHEAST BAND OF ECHOES HAS BEEN INCREASING AND SLIDING EAST. AT
08Z...SNOW WAS REACHING THE GROUND AT ANW AND TIF. HOW DOES THIS
MATCH OF WITH THE PROGS...THE NAM WAS DRY AND THE
SREF/GFS/EC/RAP/HRRR...ALL SHOWED SOME PRECIP IN THIS AREA TO
VARYING DEGREES.
THERE ARE THREE PERIODS WHEN WE MAY SEE LIGHT SNOW.
TODAY...TONIGHT INTO FRIDAY MORNING AND SATURDAY AFTERNOON INTO
SUNDAY...EACH PROGRESSIVELY MORE ORGANIZED.
THIS MORNING...THERE IS STRONG H85 WARM AIR ADVECTION ACROSS
KANSAS WITH A 50KT LOW LEVEL JET AND H7 WAA INTO NEBRASKA. THERE
IS SOME LIFT WITH A WEAK SHORTWAVE IN THE NORTHWEST FLOW...AND A
DECENT INCREASE MOISTURE. ACROSS PARTS OF EASTERN NEBRASKA. LOW
LEVEL DRY AIR IS IN PLACE...SO THE TOUGH CALL WILL BE WHERE TO
INCLUDE POPS...WHERE TO KEEP IT DRY AND IF IT WILL BE MEASURABLE.
IN GENERAL...THE SHORT RANGE MODELS BRING A NARROW BAND OF LIGHT
SNOW ACROSS PARTS OF EASTERN NEBRASKA WITH LITTLE OR NO
ACCCUMULATION. THE RAP APPEARS OVERDONE. WILL INCLUDE HIGHEST POPS
IN THE WRN PART OF THE FORECAST AREA AND WILL LEAVE MAINLY DRY
PARTS OF NORTHEAST AND FAR EASTERN NEBRASKA INTO PARTS OF SOUTHWEST
IOWA. CLOUDS OR LACK OF THICKER CLOUDS WILL IMPACT TEMPERATURES
AND HAVE RAISED SOME OF THE HIGHS. HIGHS IN THE 30S TO LOWER 40S.
TONIGHT AND FRIDAY MORNING LARGE SCALE LIFT OCCURS WITH A PIECE OF
ENERGY FROM THE PACIFIC NORTHWEST STORM SYSTEM ROTATING THROUGH
THE PLAINS WITH LIGHT SNOW SPREADING FROM WESTERN NEBRASKA INTO
EASTERN NEBRASKA TONIGHT AND MORE INTO WESTERN IOWA FRIDAY
MORNING...THEN WEAKENING. THERE COULD BE SOME LIGHT ACCUMULATIONS
AND FOR NOW HAVE MOST AMOUNTS AN INCH OR LESS.
THERE IS A BREAK IN THE PRECIPITATION LATER FRIDAY INTO EARLY
SATURDAY. THE H5 TROF MOVES INTO THE PLAINS SATURDAY/SATURDAY
NIGHT. THE NAM SEEMS TO BE THE OUTLIER WITH A STRONGER FAST CLOSED
LOW THAT TRACKS FARTHER NORTH. FOR NOW TRENDED WITH THE EC/GFS AND
HAVE THE HIGHEST POPS ACROSS THE SOUTHERN HALF OF THE FORECAST
AREA. THE PRECIPITATION SATURDAY COULD START AS A RAIN/SNOW MIX
BEFORE IT CHANGES OVER TO SNOW. THERE IS GOOD WRAP- AROUND
MOISTURE IN THE DENDRITIC LAYER SO THIS WILL NEED TO BE WATCHED.
IT IS EARLY TO PUT AMOUNTS ON THE SAT/SUN STORM AS THE TRACK MAY
SHIFT...THE EC/GFS ARE MORE IN THE 2 TO 6 INCH CATEGORY FOR THE
SOUTHERN HALF OF THE FORECAST AREA WITH THE HEAVY SNOW IN KANSAS
AND MISSOURI. WHILE THE NAM HAS HIGHER AMOUNTS FARTHER NORTH.
HEADLINES WILL NEED TO BE CONSIDERED IF THE SYSTEM DOES NOT TRACK
FARTHER SOUTH DUE TO THE COMBINATION OF BRISK WINDS AND SNOW.
&&
.AVIATION...
...06Z TAFS FOR KOFK...KLNK AND KOMA.
VFR CONDITIONS WILL PREVAIL MOST OF THE TAF PERIOD AT ALL SITES.
INCREASING MID AND HIGH CLOUDS WILL SPILL EAST...LOWERING CIGS TO
BETWEEN FL050 AND FL100 DURING THE DAY THURSDAY. A NARROW BAND OF
LIGHT SNOW COULD DEVELOP BETWEEN 16Z AND 20Z...BRIEFLY DROPPING
VSBYS/CIGS TO MVFR AT KOFK AND KLNK. OTHERWISE EXPECT LOWERING
CIGS AFTER 00Z AS ANOTHER SYSTEM PUSHES INTO THE REGION...BUT VFR
SHOULD RULE THROUGH 06Z.
DERGAN
&&
.OAX WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
IA...NONE.
&&
$$
ZAPOTOCNY
AREA FORECAST DISCUSSION
NWS TOPEKA KS
1008 AM CDT THU MAR 21 2013
.DISCUSSION...
RADAR HAS SHOWN A PERSISTENT BAND OF RETURNS ACROSS NORTHEAST KS.
THE LAST COUPLE OBS FORM KLWC AND A FEW PUBLIC REPORTS INDICATE
THERE IS NOT MUCH PRECIP FALLING FROM THIS BAND ON RADAR. THINK THIS
MAY BE DUE TO MORE DRY AIR IN THE BOUNDARY LAYER THAN EXPECTED AS
DEWPOINT TEMPS HAVE STRUGGLED TO WARM INTO THE MID AND UPPER TEENS
WHILE THE FORECAST WAS EXPECTING DEWPOINTS AROUND 20 BY NOW. ALSO
FORCING FOR PRECIP APPEARS TO BE COMPLETELY MESOSCALE DRIVEN WITH A
BAND OF FRONTOGENESIS COLLOCATED WHERE THE RADAR SHOWS THE
REFLECTIVITY. THIS BAND OF FRONTOGENESIS IS PROGGED TO SLOWLY MOVE
EAST WHILE A SHORTWAVE RIDGE AXIS BUILD UP JUST TO THE WEST OF THE
FORECAST AREA. IN GENERAL THE 12Z NAM AND RAP ARE POINTING TO A
LIGHT QPF EVENT IF ANYTHING FALLS WITH ONLY MARGINAL FORCING AT
BEST. THEREFORE WILL TREND POPS DOWN FOR TODAY WITH SOME LIKELY POPS
STILL IN THE FAR EASTERN COUNTIES. SNOW ACCUMULATIONS ARE EXPECTED
TO BE LESS THAN AN INCH GIVEN SOIL TEMPS AROUND 40 DEGREES AND KDOT
REPORTING ROAD TEMPS GENERALLY ABOVE FREEZING.
WOLTERS
&&
.AVIATION...
FOR THE 12Z TAFS...CHALLENGING FORECAST AS DRIER AIR AT THE SURFACE
IS AT ODDS WITH INCREASING MID LEVEL INSTABILITY ASSOCIATED WITH THE
DEVELOPING -SN OVER SOUTHEAST NEBRASKA. LATEST HRRR AND NAM
FORECASTS KEEP VFR AT KMHK WITH THE MAJORITY OF -SN EAST WITH
PERHAPS A BRIEF PERIOD OF -SN AT KTOP/KFOE AFT 15Z. CIGS SHOULD
GRADUALLY LOWER AT KTOP/KFOE FROM VFR TO MVFR AT THIS TIME. DRY AIR
ALOFT WILL THEN FILTER THROUGH WITH DRIZZLE OR FREEZING DRIZZLE
EXPECTED AS TEMPS HOVER AROUND THE FREEZING MARK AFT 18Z AT
KTOP/KFOE. KEPT KMHK DRY FOR THE AFTERNOON AS CONFIDENCE IN ENOUGH
LIFT TO GENERATE PRECIP IS TOO LOW UNTIL A STRONGER WAVE IS PROGGED
TO IMPACT TERMINALS AFT 03Z. TIMING MAY NEED TO BE REFINED IN FUTURE
ISSUANCES BUT BELIEVE -SN CAN BE EXPECTED AS CIGS DETERIORATE TO
IFR. WIND GUSTS INCREASE AOA 10 KTS AT KTOP/KFOE WITH GUSTS AOA
20KTS AT KMHK THROUGH THE AFTERNOON.
BOWEN
&&
.PREV DISCUSSION... /449 AM CDT THU MAR 21 2013/
THE MAIN FOCUS FOR THE FORECAST PERIOD IS ON TWO ROUNDS OF
PRECIPITATION THAT ARE EXPECTED TO RESULT IN A VARIETY OF DIFFERENT
PRECIPITATION TYPES TODAY THROUGH THE WEEKEND.
EARLY THIS MORNING...THE REGION WAS WEDGED BETWEEN TWO UPPER LEVEL
TROUGHS LOCATED OVER THE NORTHERN ROCKIES AND ACROSS THE GREAT
LAKES REGION. AS OF 09Z...LIGHT SNOW WAS FALLING ACROSS PORTIONS OF
CENTRAL AND SOUTH CENTRAL NEBRASKA IN ASSOCIATION WITH THE SHORTWAVE
THAT WILL TRACK SOUTHEASTWARD ACROSS EASTERN KANSAS AND WESTERN
MISSOURI TODAY. 00Z MODEL RUNS HAVE CONTINUED TO TREND A BIT FURTHER
DOWNWARD WITH REGARDS TO EXPECTED PRECIPITATION ACROSS THE FORECAST
AREA. A NARROW BAND OF FRONTOGENESIS LOOKS TO DEVELOP ACROSS
NORTHEASTERN AND EAST CENTRAL KANSAS BY MID MORNING...BUT WILL SHIFT
EASTWARD INTO MISSOURI DURING THE AFTERNOON HOURS. AN AREA OF
ISENTROPIC LIFT LOOKS TO BE PRESENT IN THAT REGION AS WELL DURING
THE MID/LATE MORNING HOURS INTO EARLY AFTERNOON. AS A
RESULT...MODELS ARE SUGGESTING THAT A SOMEWHAT NARROW BAND OF LIGHT
TO MODERATE SNOW WILL DEVELOP ACROSS FAR NORTHEAST AND EAST
CENTRAL KANSAS THIS MORNING INTO THE EARLY AFTERNOON HOURS.
HOWEVER...MODELS HAVE CONTINUED TO SHOW THAT AS THE BETTER
FRONTOGENESIS AND LIFT SHIFTS EASTWARD INTO MISSOURI...SO WILL THE
SATURATION ALOFT. MODEL SOUNDINGS SHOW SATURATION IN THE -10C TO
-20C ICE GROWTH ZONE DECREASING DURING THE AFTERNOON HOURS. WITH
TEMPERATURES EXPECTED TO RISE INTO THE UPPER 30S/LOW 40S ACROSS THE
WESTERN HALF OF THE FORECAST AREA...EXPECT TO SEE A TRANSITION FROM
LIGHT SNOW TO AREAS OF LIGHT RAIN OR POSSIBLY JUST DRIZZLE WITH THE
DECREASED SATURATION. ACROSS THE EASTERN HALF OF THE FORECAST
AREA...TEMPERATURES MAY STRUGGLE TO GET OUT OF THE LOW/MID 30S.
THESE TEMPERATURES HOVERING NEAR THE FREEZING MARK COMBINED WITH
MORE A SHALLOW MOISTURE PROFILE WILL RESULT IN LIGHT SNOW OR AREAS
OF FREEZING DRIZZLE DURING THE AFTERNOON HOURS. QPF AMOUNTS LOOK TO
REMAIN BELOW ONE-QUARTER INCH...WITH ONLY A TRACE TO A FEW
HUNDREDTHS EXPECTED ACROSS CENTRAL KANSAS. A SHALLOW MOISTURE
PROFILE LOOKS TO STAY IN PLACE ACROSS THE REGION THIS EVENING...WITH
MODELS SHOWING ANOTHER WEAK WAVE PASSING OVER THE REGION THAT COULD
BRING ANOTHER SHOT OF LIGHT PRECIPITATION TO THE REGION DURING THE
OVERNIGHT HOURS THROUGH FRIDAY MORNING. DEPENDING UPON THE EXACT
TRACK OF THIS SECOND WAVE OF MOISTURE...SOME LOCATIONS COULD SEE
SATURATION RETURNING IN THE ICE GROWTH ZONE. THERE IS STILL A GREAT
DEAL OF UNCERTAINTY IN THE TRACKING OF THIS ADDITIONAL PRECIPITATION
EARLY FRIDAY MORNING...SO COULD SEE AREAS OF LIGHT SNOW OR FREEZING
DRIZZLE THROUGH THE OVERNIGHT HOURS INTO FRIDAY MORNING.
PRECIPITATION SHOULD EXIT EAST OF THE AREA BY THE AFTERNOON HOURS ON
FRIDAY. SNOWFALL AMOUNTS TODAY THROUGH FRIDAY MORNING LOOK TO BE
LESS THAN 2 INCHES FOR MUCH OF THE FORECAST AREA...WITH 2 TO 3
INCHES POSSIBLE IN FAR EAST CENTRAL KANSAS.
THE SECOND...AND MORE SIGNIFICANT...ROUND OF PRECIPITATION IS
EXPECTED THIS WEEKEND AS THE TROUGH OVER THE NORTHERN ROCKIES DIGS
SOUTHWARD INTO THE CENTRAL AND SOUTHERN PLAINS. WHILE THERE ARE
STILL MODEL DISCREPANCIES IN THE EXACT TRACK OF THIS UPPER
LOW...MODELS HAVE CONTINUED TO TREND WITH A MORE SOUTHERN TRACK TO
THE LOW...WITH IT GENERALLY MOVING EAST NEAR THE KANSAS/OKLAHOMA
BORDER BEFORE PROGRESSING TOWARD THE OHIO RIVER VALLEY. WITH THIS
SOUTHERN TRACK...THAT PUTS THE FORECAST AREA IN THE COLD REGION OF
THE SYSTEM. THE COMBINATION OF DECENT LIFT AND SUFFICIENT AVAILABLE
MOISTURE WITH THIS SYSTEM WILL RESULT IN MORE WIDESPREAD
PRECIPITATION ACROSS THE FORECAST AREA...WITH QPF AMOUNTS UPWARDS OF
0.50 TO 0.75 INCH POSSIBLE. PRECIPITATION IS EXPECTED TO MOVE INTO
THE AREA EARLY SATURDAY MORNING AND EXIT EAST OF THE AREA BY SUNDAY
AFTERNOON/EVENING. COULD SEE A MIX OF RAIN AND SNOW DURING THE
DAYTIME HOURS WITH PREDOMINANTLY SNOW EXPECTED DURING THE EVENING
HOURS. ALTHOUGH THERE IS STILL A GREAT DEAL OF UNCERTAINTY WITH
EXPECTED SNOWFALL TOTALS ACROSS THE REGION...SEVERAL INCHES OF SNOW
CERTAINLY ARE POSSIBLE ACROSS THE ENTIRE FORECAST AREA.
ONCE THIS SYSTEM MOVES OUT OF THE AREA BY THE END OF THE
WEEKEND...THE FIRST HALF OF THE WEEK LOOKS TO BE PREDOMINANTLY DRY
AS SURFACE HIGH PRESSURE BUILDS INTO THE CENTRAL CONUS. A BROAD
UPPER LEVEL TROUGH LOOKS TO BECOME ANCHORED ACROSS MUCH OF THE
NORTHERN U.S. MODELS HINT AT THE POSSIBILITY FOR A FEW EMBEDDED
SHORTWAVES TO DEVELOP ALONG THIS TROUGH...AND HAVE ADDED SLIGHT
CHANCE POPS TO THE FORECAST ON WEDNESDAY. TEMPERATURES THROUGH THE
FIRST HALF OF NEXT WEEK STILL LOOK TO REMAIN WELL BELOW SEASONAL
NORMALS...WHICH ARE ACTUALLY IN THE UPPER 50S...WITH HIGHS ONLY IN
THE UPPER 30S TO MID 40S.
ACH
&&
.TOP WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS TOPEKA KS
649 AM CDT THU MAR 21 2013
...UPDATE TO AVIATION...
.DISCUSSION...
THE MAIN FOCUS FOR THE FORECAST PERIOD IS ON TWO ROUNDS OF
PRECIPITATION THAT ARE EXPECTED TO RESULT IN A VARIETY OF DIFFERENT
PRECIPITATION TYPES TODAY THROUGH THE WEEKEND.
EARLY THIS MORNING...THE REGION WAS WEDGED BETWEEN TWO UPPER LEVEL
TROUGHS LOCATED OVER THE NORTHERN ROCKIES AND ACROSS THE GREAT
LAKES REGION. AS OF 09Z...LIGHT SNOW WAS FALLING ACROSS PORTIONS OF
CENTRAL AND SOUTH CENTRAL NEBRASKA IN ASSOCIATION WITH THE SHORTWAVE
THAT WILL TRACK SOUTHEASTWARD ACROSS EASTERN KANSAS AND WESTERN
MISSOURI TODAY. 00Z MODEL RUNS HAVE CONTINUED TO TREND A BIT FURTHER
DOWNWARD WITH REGARDS TO EXPECTED PRECIPITATION ACROSS THE FORECAST
AREA. A NARROW BAND OF FRONTOGENESIS LOOKS TO DEVELOP ACROSS
NORTHEASTERN AND EAST CENTRAL KANSAS BY MID MORNING...BUT WILL SHIFT
EASTWARD INTO MISSOURI DURING THE AFTERNOON HOURS. AN AREA OF
ISENTROPIC LIFT LOOKS TO BE PRESENT IN THAT REGION AS WELL DURING
THE MID/LATE MORNING HOURS INTO EARLY AFTERNOON. AS A
RESULT...MODELS ARE SUGGESTING THAT A SOMEWHAT NARROW BAND OF LIGHT
TO MODERATE SNOW WILL DEVELOP ACROSS FAR NORTHEAST AND EAST
CENTRAL KANSAS THIS MORNING INTO THE EARLY AFTERNOON HOURS.
HOWEVER...MODELS HAVE CONTINUED TO SHOW THAT AS THE BETTER
FRONTOGENESIS AND LIFT SHIFTS EASTWARD INTO MISSOURI...SO WILL THE
SATURATION ALOFT. MODEL SOUNDINGS SHOW SATURATION IN THE -10C TO
-20C ICE GROWTH ZONE DECREASING DURING THE AFTERNOON HOURS. WITH
TEMPERATURES EXPECTED TO RISE INTO THE UPPER 30S/LOW 40S ACROSS THE
WESTERN HALF OF THE FORECAST AREA...EXPECT TO SEE A TRANSITION FROM
LIGHT SNOW TO AREAS OF LIGHT RAIN OR POSSIBLY JUST DRIZZLE WITH THE
DECREASED SATURATION. ACROSS THE EASTERN HALF OF THE FORECAST
AREA...TEMPERATURES MAY STRUGGLE TO GET OUT OF THE LOW/MID 30S.
THESE TEMPERATURES HOVERING NEAR THE FREEZING MARK COMBINED WITH
MORE A SHALLOW MOISTURE PROFILE WILL RESULT IN LIGHT SNOW OR AREAS
OF FREEZING DRIZZLE DURING THE AFTERNOON HOURS. QPF AMOUNTS LOOK TO
REMAIN BELOW ONE-QUARTER INCH...WITH ONLY A TRACE TO A FEW
HUNDREDTHS EXPECTED ACROSS CENTRAL KANSAS. A SHALLOW MOISTURE
PROFILE LOOKS TO STAY IN PLACE ACROSS THE REGION THIS EVENING...WITH
MODELS SHOWING ANOTHER WEAK WAVE PASSING OVER THE REGION THAT COULD
BRING ANOTHER SHOT OF LIGHT PRECIPITATION TO THE REGION DURING THE
OVERNIGHT HOURS THROUGH FRIDAY MORNING. DEPENDING UPON THE EXACT
TRACK OF THIS SECOND WAVE OF MOISTURE...SOME LOCATIONS COULD SEE
SATURATION RETURNING IN THE ICE GROWTH ZONE. THERE IS STILL A GREAT
DEAL OF UNCERTAINTY IN THE TRACKING OF THIS ADDITIONAL PRECIPITATION
EARLY FRIDAY MORNING...SO COULD SEE AREAS OF LIGHT SNOW OR FREEZING
DRIZZLE THROUGH THE OVERNIGHT HOURS INTO FRIDAY MORNING.
PRECIPITATION SHOULD EXIT EAST OF THE AREA BY THE AFTERNOON HOURS ON
FRIDAY. SNOWFALL AMOUNTS TODAY THROUGH FRIDAY MORNING LOOK TO BE
LESS THAN 2 INCHES FOR MUCH OF THE FORECAST AREA...WITH 2 TO 3
INCHES POSSIBLE IN FAR EAST CENTRAL KANSAS.
THE SECOND...AND MORE SIGNIFICANT...ROUND OF PRECIPITATION IS
EXPECTED THIS WEEKEND AS THE TROUGH OVER THE NORTHERN ROCKIES DIGS
SOUTHWARD INTO THE CENTRAL AND SOUTHERN PLAINS. WHILE THERE ARE
STILL MODEL DISCREPANCIES IN THE EXACT TRACK OF THIS UPPER
LOW...MODELS HAVE CONTINUED TO TREND WITH A MORE SOUTHERN TRACK TO
THE LOW...WITH IT GENERALLY MOVING EAST NEAR THE KANSAS/OKLAHOMA
BORDER BEFORE PROGRESSING TOWARD THE OHIO RIVER VALLEY. WITH THIS
SOUTHERN TRACK...THAT PUTS THE FORECAST AREA IN THE COLD REGION OF
THE SYSTEM. THE COMBINATION OF DECENT LIFT AND SUFFICIENT AVAILABLE
MOISTURE WITH THIS SYSTEM WILL RESULT IN MORE WIDESPREAD
PRECIPITATION ACROSS THE FORECAST AREA...WITH QPF AMOUNTS UPWARDS OF
0.50 TO 0.75 INCH POSSIBLE. PRECIPITATION IS EXPECTED TO MOVE INTO
THE AREA EARLY SATURDAY MORNING AND EXIT EAST OF THE AREA BY SUNDAY
AFTERNOON/EVENING. COULD SEE A MIX OF RAIN AND SNOW DURING THE
DAYTIME HOURS WITH PREDOMINANTLY SNOW EXPECTED DURING THE EVENING
HOURS. ALTHOUGH THERE IS STILL A GREAT DEAL OF UNCERTAINTY WITH
EXPECTED SNOWFALL TOTALS ACROSS THE REGION...SEVERAL INCHES OF SNOW
CERTAINLY ARE POSSIBLE ACROSS THE ENTIRE FORECAST AREA.
ONCE THIS SYSTEM MOVES OUT OF THE AREA BY THE END OF THE
WEEKEND...THE FIRST HALF OF THE WEEK LOOKS TO BE PREDOMINANTLY DRY
AS SURFACE HIGH PRESSURE BUILDS INTO THE CENTRAL CONUS. A BROAD
UPPER LEVEL TROUGH LOOKS TO BECOME ANCHORED ACROSS MUCH OF THE
NORTHERN U.S. MODELS HINT AT THE POSSIBILITY FOR A FEW EMBEDDED
SHORTWAVES TO DEVELOP ALONG THIS TROUGH...AND HAVE ADDED SLIGHT
CHANCE POPS TO THE FORECAST ON WEDNESDAY. TEMPERATURES THROUGH THE
FIRST HALF OF NEXT WEEK STILL LOOK TO REMAIN WELL BELOW SEASONAL
NORMALS...WHICH ARE ACTUALLY IN THE UPPER 50S...WITH HIGHS ONLY IN
THE UPPER 30S TO MID 40S.
ACH
&&
.AVIATION...
FOR THE 12Z TAFS...CHALLENGING FORECAST AS DRIER AIR AT THE SURFACE
IS AT ODDS WITH INCREASING MID LEVEL INSTABILITY ASSOCIATED WITH THE
DEVELOPING -SN OVER SOUTHEAST NEBRASKA. LATEST HRRR AND NAM
FORECASTS KEEP VFR AT KMHK WITH THE MAJORITY OF -SN EAST WITH
PERHAPS A BRIEF PERIOD OF -SN AT KTOP/KFOE AFT 15Z. CIGS SHOULD
GRADUALLY LOWER AT KTOP/KFOE FROM VFR TO MVFR AT THIS TIME. DRY
AIR ALOFT WILL THEN FILTER THROUGH WITH DRIZZLE OR FREEZING
DRIZZLE EXPECTED AS TEMPS HOVER AROUND THE FREEZING MARK AFT 18Z
AT KTOP/KFOE. KEPT KMHK DRY FOR THE AFTERNOON AS CONFIDENCE IN
ENOUGH LIFT TO GENERATE PRECIP IS TOO LOW UNTIL A STRONGER WAVE IS
PROGGED TO IMPACT TERMINALS AFT 03Z. TIMING MAY NEED TO BE REFINED
IN FUTURE ISSUANCES BUT BELIEVE -SN CAN BE EXPECTED AS CIGS
DETERIORATE TO IFR. WIND GUSTS INCREASE AOA 10 KTS AT KTOP/KFOE
WITH GUSTS AOA 20KTS AT KMHK THROUGH THE AFTERNOON.
BOWEN
&&
.TOP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS GRAND RAPIDS MI
722 AM EDT THU MAR 21 2013
.SYNOPSIS...
ISSUED AT 334 AM EDT THU MAR 21 2013
THE REGION WILL CONTINUE TO SEE SNOW SHOWERS TODAY...HOWEVER THEY
SHOULD GRADUALLY BECOME MORE SCATTERED. ANY ADDITIONAL ACCUMULATION
SHOULD REMAIN AN INCH OR LESS IN MOST PLACES. THE SNOW WILL COME TO
AN END...OR DIMINISH TO FLURRIES LATE TONIGHT. HIGHS TODAY WILL BE
IN THE UPPER 20S TO AROUND 30.
FRIDAY AND SATURDAY WILL SEE QUIET WEATHER WITH A SLIGHT WARMING
TREND WITH HIGHS GETTING INTO THE 30S EACH DAY.
THERE WILL BE THE CHANCE OF RAIN OR SNOW RETURNING MONDAY AND
TUESDAY OF NEXT WEEK.
&&
.UPDATE...
ISSUED AT 720 AM EDT THU MAR 21 2013
THE WEATHER WINTER WEATHER ADVISORY HAS BEEN CANCELED SINCE ANY
REMAINING SNOWFALL IS LIGHT AND THAT IS DIMINISHING.
UPDATE ISSUED AT 647 AM EDT THU MAR 21 2013
LOOKING AT THE LATEST RADAR LOOPS... THE HRRR MODEL OUTPUT... THE
LATEST NAM DATA (LIFT IN THE DGZ MOSTLY) IT WOULD SEEM THE THREAT
FOR SIGNIFICANT SNOW SHOWERS HAS ENDED SO I WILL DROP THE WINTER
WEATHER ADVISORY ONCE I SEND THIS MESSAGE.
&&
.SHORT TERM...(TODAY THROUGH SATURDAY)
ISSUED AT 334 AM EDT THU MAR 21 2013
WILL BUMP THE END TIME OF THE ADVISORY TO 14Z TO COVER IMPACTS
THROUGH THE MORNING COMMUTE. LAKE EFFECT SNOW SHOWERS CONTINUE...
BUT A DOMINATE BAND DID NOT DEVELOP...KEEPING ACCUMS FROM GETTING
TOO HIGH. EXPECT LAKE SHORE AREAS WILL SEE AN ADDITIONAL INCH OR
TWO THIS MORNING. INVERSION HEIGHTS AND DELTA T/S GRADUALLY BECOME
LESS FAVORABLE FOR INTENSE SNOW SHOWERS THROUGH THE DAY AND A
DOWNWARD TREND SHOULD BE SEEN BY LATE MORNING INTO THE AFTERNOON.
A SURFACE TROUGH WAS SAGGING SOUTH OVER NORTHERN LOWER THIS
MORNING. THIS ALONG WITH DAYTIME HEATING WILL SPARK SCATTERED SNOW
SHOWERS INLAND TOO. SO WILL MAIN POPS INLAND...BUT ANY ACCUMS WILL
BE UNDER AN INCH.
THE DOWNWARD TREND IN THE SNOW ACTIVITY WILL CONTINUE INTO TONIGHT
AND SHOULD LARGELY BE JUST FLURRIES BY 06Z.
WEAK SURFACE AND UPPER RIDGING BUILDS FOR THE END OF THE WEEK.
TRENDED A BIT MORE CLOUDY FOR FRIDAY AND SATURDAY. IT APPEARS A
FAIR AMOUNT OF LOW LEVEL MOISTURE LINGERS UNDER A TEMP INVERSION.
HOWEVER GIVEN THE HIGHER SUN ANGLE AND BETTER MIXING THIS TIME OF
YEAR WOULD EXPECT TO SEE AT LEAST SOME SUN EACH DAY. LOW TO MID
30S FRI SHOULD WARM TO THE UPPER 30S TO AROUND 40 BY SATURDAY.
.LONG TERM...(SATURDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 334 AM EDT THU MAR 21 2013
WE CONTINUE TO WATCH THE SYSTEM THAT NOW LOOKS LIKE IT WILL FOR THE
MOST PART PASS SOUTH OF THE GRR CWA SUN INTO TUESDAY. OTHERWISE
COLDER THAN NORMAL TEMPERATURES WILL CONTINUE THROUGH MOST OF THIS
COMING WEEK.
THE HIGH LATITUDE BLOCKING IS FORECAST TO CONTINUES INDEFINITELY.
THIS KEEPS THE POLAR JET CORE WELL SOUTH OF MICHIGAN THROUGH NEXT
WEEK. WHICH IS WHAT KEEPS THE WARMER AIR WELL SOUTH OF MICHIGAN
TOO.
THE STORM WE ARE WATCHING COMES FROM A PACIFIC SYSTEM THAT MOVED ON
SHORE TODAY NEAR VANCOUVER BRITISH COLUMBIA. THE UPPER LEVEL ENERGY
FRAGMENTS AS THE SYSTEM MOVES THROUGH THE ROCKY MOUNTAINS THIS
WEEKEND. SO WHILE A CLOSED UPPER LOW DOES MOVE EAST OVER THE OHIO
VALLEY IN THE MONDAY TIME FRAME...TAKING THE BULK OF THE
PRECIPITATION SOUTH OF MICHIGAN WITH IT... A CONSIDERABLE AMOUNT OF
UPPER TROUGHING REMAINS WEST OF THE GREAT LAKES. SO... EVEN IF THE
STORM PRECIPITATION ITSELF MISSES SOUTHWEST LOWER MICHIGAN THE UPPER
LEVEL SYSTEM WILL STILL HAVE TO MOVE THROUGH THE AREA IN THE MON-WED
TIME FRAME. THERE IS MID LEVEL MOISTURE WITH THE UPPER LEVEL FEATURE
SO THAT WILL LEAD TO INSTABILITY SNOW SHOWERS MONDAY INTO WEDNESDAY.
ANOTHER ISSUE TOO IS SOMETIMES WHEN THERE IS SO MUCH UPPER TROUGHING
HANGING BACK...WEST OF THE GREAT LAKES THE SURFACE STORM ENDS UP
WAITING OF THE UPPER LEVEL ENERGY TO WEST TO REACH IT BEFORE MOVING
OUT... SO I AM STILL NOT TOTALLY ON BOARD WITH THIS SYSTEM STAYING
SOUTH. EVEN SO WE HAVE LOW CHANCE POPS SUN THROUGH WEDNESDAY.
IF THIS WORKS OUT AS THE CURRENT MODELS SUGGEST EXPECT PARTLY TO
MOSTLY CLOUDY SKIES... FLURRIES FROM TIME TO TIME AND TEMPERATURES
IN THE 20S AT NIGHT AND 30S DURING THE DAY (FOR THE MOST PART).
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z FRIDAY MORNING)
ISSUED AT 720 AM EDT THU MAR 21 2013
MVFR CIGS PERSIST ACROSS ALL OF LOWER MICHIGAN AT 7 AM. MVFR
VSBY IN SNOW SHOWERS SOUTH AND WEST OF GRAND RAPIDS (BIV, LWA). I
EXPECT THE SNOW SHOWERS TO CONTINUE TO WEAKEN AS MID LEVEL DRY AIR
FILTERS IN. THAT SHOULD ALSO ALLOW THE CEILING TO IMPROVE TO VFR BY
EARLY AFTERNOON.
&&
.MARINE...
ISSUED AT 334 AM EDT THU MAR 21 2013
WILL MAINTAIN SCA FOR BRISK NW WINDS INTO TONIGHT.
&&
.HYDROLOGY...
ISSUED AT 334 AM EDT THU MAR 21 2013
NO ISSUES EXPECTED.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LM...SMALL CRAFT ADVISORY UNTIL 1 AM EDT FRIDAY FOR LMZ844>849.
&&
$$
UPDATE...WDM
SYNOPSIS...JK
SHORT TERM...JK
LONG TERM...WDM
AVIATION...WDM
HYDROLOGY...JK
MARINE...JK
AREA FORECAST DISCUSSION
NWS GRAND RAPIDS MI
648 AM EDT THU MAR 21 2013
.SYNOPSIS...
ISSUED AT 334 AM EDT THU MAR 21 2013
THE REGION WILL CONTINUE TO SEE SNOW SHOWERS TODAY...HOWEVER THEY
SHOULD GRADUALLY BECOME MORE SCATTERED. ANY ADDITIONAL ACCUMULATION
SHOULD REMAIN AN INCH OR LESS IN MOST PLACES. THE SNOW WILL COME TO
AN END...OR DIMINISH TO FLURRIES LATE TONIGHT. HIGHS TODAY WILL BE
IN THE UPPER 20S TO AROUND 30.
FRIDAY AND SATURDAY WILL SEE QUIET WEATHER WITH A SLIGHT WARMING
TREND WITH HIGHS GETTING INTO THE 30S EACH DAY.
THERE WILL BE THE CHANCE OF RAIN OR SNOW RETURNING MONDAY AND
TUESDAY OF NEXT WEEK.
&&
.UPDATE...
ISSUED AT 647 AM EDT THU MAR 21 2013
LOOKING AT THE LATEST RADAR LOOPS... THE HRRR MODEL OUTPUT... THE
LATEST NAM DATA (LIFT IN THE DGZ MOSTLY) IT WOULD SEEM THE THREAT
FOR SIGNIFICANT SNOW SHOWERS HAS ENDED SO I WILL DROP THE WINTER
WEATHER ADVISORY ONCE I SEND THIS MESSAGE.
&&
.SHORT TERM...(TODAY THROUGH SATURDAY)
ISSUED AT 334 AM EDT THU MAR 21 2013
WILL BUMP THE END TIME OF THE ADVISORY TO 14Z TO COVER IMPACTS
THROUGH THE MORNING COMMUTE. LAKE EFFECT SNOW SHOWERS CONTINUE...
BUT A DOMINATE BAND DID NOT DEVELOP...KEEPING ACCUMS FROM GETTING
TOO HIGH. EXPECT LAKE SHORE AREAS WILL SEE AN ADDITIONAL INCH OR
TWO THIS MORNING. INVERSION HEIGHTS AND DELTA T/S GRADUALLY BECOME
LESS FAVORABLE FOR INTENSE SNOW SHOWERS THROUGH THE DAY AND A
DOWNWARD TREND SHOULD BE SEEN BY LATE MORNING INTO THE AFTERNOON.
A SURFACE TROUGH WAS SAGGING SOUTH OVER NORTHERN LOWER THIS
MORNING. THIS ALONG WITH DAYTIME HEATING WILL SPARK SCATTERED SNOW
SHOWERS INLAND TOO. SO WILL MAIN POPS INLAND...BUT ANY ACCUMS WILL
BE UNDER AN INCH.
THE DOWNWARD TREND IN THE SNOW ACTIVITY WILL CONTINUE INTO TONIGHT
AND SHOULD LARGELY BE JUST FLURRIES BY 06Z.
WEAK SURFACE AND UPPER RIDGING BUILDS FOR THE END OF THE WEEK.
TRENDED A BIT MORE CLOUDY FOR FRIDAY AND SATURDAY. IT APPEARS A
FAIR AMOUNT OF LOW LEVEL MOISTURE LINGERS UNDER A TEMP INVERSION.
HOWEVER GIVEN THE HIGHER SUN ANGLE AND BETTER MIXING THIS TIME OF
YEAR WOULD EXPECT TO SEE AT LEAST SOME SUN EACH DAY. LOW TO MID
30S FRI SHOULD WARM TO THE UPPER 30S TO AROUND 40 BY SATURDAY.
.LONG TERM...(SATURDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 334 AM EDT THU MAR 21 2013
WE CONTINUE TO WATCH THE SYSTEM THAT NOW LOOKS LIKE IT WILL FOR THE
MOST PART PASS SOUTH OF THE GRR CWA SUN INTO TUESDAY. OTHERWISE
COLDER THAN NORMAL TEMPERATURES WILL CONTINUE THROUGH MOST OF THIS
COMING WEEK.
THE HIGH LATITUDE BLOCKING IS FORECAST TO CONTINUES INDEFINITELY.
THIS KEEPS THE POLAR JET CORE WELL SOUTH OF MICHIGAN THROUGH NEXT
WEEK. WHICH IS WHAT KEEPS THE WARMER AIR WELL SOUTH OF MICHIGAN
TOO.
THE STORM WE ARE WATCHING COMES FROM A PACIFIC SYSTEM THAT MOVED ON
SHORE TODAY NEAR VANCOUVER BRITISH COLUMBIA. THE UPPER LEVEL ENERGY
FRAGMENTS AS THE SYSTEM MOVES THROUGH THE ROCKY MOUNTAINS THIS
WEEKEND. SO WHILE A CLOSED UPPER LOW DOES MOVE EAST OVER THE OHIO
VALLEY IN THE MONDAY TIME FRAME...TAKING THE BULK OF THE
PRECIPITATION SOUTH OF MICHIGAN WITH IT... A CONSIDERABLE AMOUNT OF
UPPER TROUGHING REMAINS WEST OF THE GREAT LAKES. SO... EVEN IF THE
STORM PRECIPITATION ITSELF MISSES SOUTHWEST LOWER MICHIGAN THE UPPER
LEVEL SYSTEM WILL STILL HAVE TO MOVE THROUGH THE AREA IN THE MON-WED
TIME FRAME. THERE IS MID LEVEL MOISTURE WITH THE UPPER LEVEL FEATURE
SO THAT WILL LEAD TO INSTABILITY SNOW SHOWERS MONDAY INTO WEDNESDAY.
ANOTHER ISSUE TOO IS SOMETIMES WHEN THERE IS SO MUCH UPPER TROUGHING
HANGING BACK...WEST OF THE GREAT LAKES THE SURFACE STORM ENDS UP
WAITING OF THE UPPER LEVEL ENERGY TO WEST TO REACH IT BEFORE MOVING
OUT... SO I AM STILL NOT TOTALLY ON BOARD WITH THIS SYSTEM STAYING
SOUTH. EVEN SO WE HAVE LOW CHANCE POPS SUN THROUGH WEDNESDAY.
IF THIS WORKS OUT AS THE CURRENT MODELS SUGGEST EXPECT PARTLY TO
MOSTLY CLOUDY SKIES... FLURRIES FROM TIME TO TIME AND TEMPERATURES
IN THE 20S AT NIGHT AND 30S DURING THE DAY (FOR THE MOST PART).
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z THURSDAY NIGHT)
ISSUED AT 1206 AM EDT THU MAR 21 2013
CLOUDS AND SNOW SHOWERS HAVE MIGRATED WEST TOWARD THE LAKESHORE AS
OF 04Z. INLAND AREAS HAVE GONE VFR...WITH CLEARING IN MANY AREAS
WHILE THE LAKESHORE VARIES BETWEEN VFR AND IFR AS SNOW SHOWERS
MOVE THROUGH. THIS SHOULD REMAIN THE CASE THROUGH THE NIGHT WITH
VFR CONDITIONS INLAND AND VARIABLE CONDITIONS TOWARD THE LAKE.
THE SNOW SHOWERS SHOULD TAPER TO FLURRIES THURSDAY MORNING AFTER
DAYBREAK BEFORE ENDING TOWARD MIDDAY. CONDITIONS SHOULD BE VFR
DURING THE AFTERNOON AND EVENING WITH SOME STRATOCUMULUS FLOATING
INLAND OFF LAKE MICHIGAN WITH BASES ABOVE 3000FT.
&&
.MARINE...
ISSUED AT 334 AM EDT THU MAR 21 2013
WILL MAINTAIN SCA FOR BRISK NW WINDS INTO TONIGHT.
&&
.HYDROLOGY...
ISSUED AT 334 AM EDT THU MAR 21 2013
NO ISSUES EXPECTED.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...LAKE EFFECT SNOW ADVISORY UNTIL 10 AM EDT THIS MORNING FOR
MIZ037-043-050-056-064-071-072.
LM...SMALL CRAFT ADVISORY UNTIL 1 AM EDT FRIDAY FOR LMZ844>849.
&&
$$
UPDATE...WDM
SYNOPSIS...JK
SHORT TERM...JK
LONG TERM...WDM
AVIATION...DUKE
HYDROLOGY...JK
MARINE...JK
AREA FORECAST DISCUSSION
NWS DULUTH MN
950 AM CDT THU MAR 21 2013
.UPDATE...
THE FORECAST WAS UPDATED THROUGH THIS EVENING. THE CHANGES WERE
MOSTLY MINOR...BUT MADE SOME CHANGES TO CLOUD COVER BASED ON THE
LATEST TRENDS. THE PREVIOUS FORECAST WAS CALLING FOR A LOT OF
DEVELOPING CLOUD COVER ACROSS THE WESTERN FORECAST AREA SIMILAR TO
WHAT THE ARROWHEAD AND NW WISCONSIN CURRENTLY HAVE. HOWEVER...THE
MODELS WERE CALLING FOR THAT YESTERDAY TOO...BUT THE CLOUDS MOSTLY
REMAINED IN THE ARROWHEAD AND NW WISCONSIN. THEREFORE...CHANGED
THE FORECAST TO REFLECT MY SKEPTICISM...BUT DID FORECAST MOSTLY TO
PARTLY SUNNY SKIES ACROSS THE WESTERN FORECAST AREA IN CASE
CLOUDS DO DEVELOP. FOR THIS MORNING AND EARLY THIS AFTERNOON...MADE
SURE WE HAD SCATTERED FLURRIES IN THE FORECAST FOR MOST OF THE
AREAS THAT CURRENTLY HAVE BKN/OVC CLOUD COVER. THE HIGH
TEMPERATURE FORECAST MOSTLY LOOKED GOOD...BUT LOWERED THE
TEMPERATURES ACROSS THE ARROWHEAD A BIT DUE TO THE CLOUD COVER.
&&
.PREV DISCUSSION... /ISSUED 648 AM CDT THU MAR 21 2013/
AVIATION...12Z TAF ISSUANCE.
A SHORT WAVE WILL SPREAD A STRATUS DECK SOUTH AND EAST OVER MUCH
OF THE FORECAST AREA TODAY. PREVAILING MVFR CIGS OF 2-3 KFT WILL
BE FOUND IN THE EASTERN TERMINALS...INCLUDING KHIB/KHYR.
TERMINALS FURTHER WEST...INCLUDING KINL/KBRD CAN EXPECT VFR
CONDITIONS WITH PERIODS OF MVFR CIGS. GENERALLY CLR SKIES AND VFR
CIGS WILL PREVAIL OVERNIGHT...WITH AREAS OF RESTRICTED VSBYS OF
3-5 SM DUE TO POSSIBLE LIGHT FG/BR AFTER 06Z.
PREV DISCUSSION... /ISSUED 329 AM CDT THU MAR 21 2013/
SHORT TERM...THROUGH FRIDAY.
A SHORTWAVE...WHICH IS AN EXTENSION OF THE LARGE EASTERN
CONUS/EASTERN CANADIAN UPPER TROUGH...WAS MOVING THROUGH THE
NORTHLAND AND SHOULD MOVE SOUTH AND EAST TODAY.
THERE CONTINUED TO BE SOME FLURRIES FALLING OUT OF A DECK OF CLOUDS
THAT COVERED PORTIONS OF NORTHEAST MINNESOTA AND NORTHERN
WISCONSIN...AND SOME LAKE EFFECT SNOW SHOWERS CONTINUED ALONG THE
SOUTH SHORE. CONDITIONS BECOME LESS FAVORABLE FOR LES TODAY...AS
850MB TEMPERATURES WARM THROUGH THE MORNING WITH DRIER AIR MOVING
OVER LAKE SUPERIOR. WE DON`T EXPECT MUCH ACCUMULATION THIS MORNING
OVER THE SNOWBELT REGION. CLOUD COVER WILL BE A CHALLENGE TODAY. THE
WESTERN EDGE OF THE CLOUDS THIS MORNING WAS MOVING SLOWLY EAST AND
THE CLOUDS APPEAR TO BE DIMINISHING. HOWEVER...THE RAP SUGGESTS
WE`LL SEE SOME REDEVELOPMENT BY LATE MORNING/EARLY AFTERNOON WITH
SOME HEATING. WE DID FOLLOW THAT TREND...AND HAVE PARTLY TO MOSTLY
CLOUDY SKIES GOING FOR ABOUT THE SOUTHERN HALF TO TWO THIRDS OF THE
CWA THROUGH MID AFTERNOON. WE EXPECT HIGHS TODAY TO BE MAINLY IN THE
MID TWENTIES...BUT WILL HAVE TO ADJUST A FEW DEGREES DEPENDING ON
THE EXTENT OF THE CLOUD COVER.
TONIGHT INTO FRIDAY THE NORTHLAND GETS SQUEEZED BETWEEN TWO
TROUGHS...ONE EXTENDING FROM NORTHERN BRITISH COLUMBIA INTO THE
NORTHERN PLAINS...AND THE PERSISTENT EASTERN TROUGH. WE EXPECT
TONIGHT TO BE CLEAR TO PARTLY CLOUDY FOR MOST AREAS WITH LIGHTER
WINDS. WE WENT BELOW MOST OF THE LOW TEMP GUIDANCE TONIGHT...CLOSER
TO THE NHGEMBC. DEEP SNOWPACK...LIGHT WINDS AND MINIMAL CLOUD COVER
SHOULD ALLOW FOR THE COLD TEMPS. THICKER CLOUDS WILL MOVE INTO THE
ARROWHEAD/BORDER REGION LATER TONIGHT...AND THAT WILL KEEP THEM FROM
REALLY GETTING COLD.
FRIDAY WILL BE PARTLY SUNNY WITH HIGHS A BIT WARMER...FROM 28 TO 34
FOR MOST AREAS.
LONG TERM...FRIDAY NIGHT THROUGH THURSDAY.
THE WESTERN LAKE SUPERIOR REGION WILL SITUATED BETWEEN A LARGE CUT
OFF LOW ROTATING OVER THE NEW ENGLAND STATES...AND A DIGGING TROUGH
OVER THE ROCKIES THROUGH THE WEEKEND. THIS WILL RESULT IN WEAK SFC
RIDGING OVER THE CWA FRIDAY NIGHT/SAT. A NORTH TO NORTHEAST FLOW
WILL DEVELOP SAT NIGHT THROUGH SUNDAY AS A VORT MAX WITH SFC
REFLECTION LOW EJECTS OUT OF THE BASE OF THE TROUGH AND TRACKS EAST
ACROSS THE SRN PLAINS. AT THIS TIME...MODELS IN AGREEMENT THAT THE
NRN EXTENT OF ANY PRECIPITATION ASSOCIATED WITH THE WAVE TRANSLATES
ALONG THE SOUTHERN MN/WI STATE LINES. MEANWHILE...AN ELONGATED VORT
MAX BREAKS FREE FROM THE EASTERN LOW...AND RETROGRADES ACROSS
ONTARIO FRIDAY NIGHT...DROPPING INTO THE NRN LAKE SUPERIOR/MN
ARROWHEAD REGION SATURDAY. ATTM...THIS VORT IS EXPECTED TO BRING
PRIMARILY INCREASING CLOUDS. HOWEVER...RH FIELDS AND LATEST NAM BUFR
SOUNDINGS SHOWS INCREASING LOW LEVEL MOISTURE FRI NIGHT THAT
SUGGESTS A SMALL POTENTIAL FOR SOME FOG/BR OR POSSIBLY VERY LIGHT
DZ/SN SAT/SAT NIGHT. HOWEVER...HAVE KEPT FCST DRY THROUGH THE
WEEKEND AS ANY THE PRECIP CHCS ARE VERY SMALL AND QPF WILL BE
ISOLATED AND LIGHT.
BEYOND THE WEEKEND...THE H50 FLOW BECOMES VERY DISORGANIZED AS
MODELS TRY TO RESOLVE PHASING THE DOUBLE LOWS OVER THE ERN COAST.
GENIALLY HAVE KEPT EXTENDED DRY WITH TEMPERATURES NEAR TO A FEW
DEGREES BELOW NORMAL.
&&
.POINT TEMPS/POPS...
DLH 25 -1 31 13 / 10 0 10 10
INL 25 -8 30 9 / 10 0 10 10
BRD 26 -2 32 15 / 0 0 10 10
HYR 27 -5 33 11 / 10 0 10 10
ASX 26 3 31 13 / 20 10 10 10
&&
.DLH WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
&&
$$
SHORT TERM...GROCHOCINSKI
LONG TERM....TENTINGER
AREA FORECAST DISCUSSION
NWS DULUTH MN
648 AM CDT THU MAR 21 2013
.AVIATION...12Z TAF ISSUANCE.
A SHORT WAVE WILL SPREAD A STRATUS DECK SOUTH AND EAST OVER MUCH
OF THE FORECAST AREA TODAY. PREVAILING MVFR CIGS OF 2-3 KFT WILL
BE FOUND IN THE EASTERN TERMINALS...INCLUDING KHIB/KHYR.
TERMINALS FURTHER WEST...INCLUDING KINL/KBRD CAN EXPECT VFR
CONDITIONS WITH PERIODS OF MVFR CIGS. GENERALLY CLR SKIES AND VFR
CIGS WILL PREVAIL OVERNIGHT...WITH AREAS OF RESTRICTED VSBYS OF
3-5 SM DUE TO POSSIBLE LIGHT FG/BR AFTER 06Z.
&&
.PREV DISCUSSION... /ISSUED 329 AM CDT THU MAR 21 2013/
SHORT TERM...THROUGH FRIDAY.
A SHORTWAVE...WHICH IS AN EXTENSION OF THE LARGE EASTERN
CONUS/EASTERN CANADIAN UPPER TROUGH...WAS MOVING THROUGH THE
NORTHLAND AND SHOULD MOVE SOUTH AND EAST TODAY.
THERE CONTINUED TO BE SOME FLURRIES FALLING OUT OF A DECK OF CLOUDS
THAT COVERED PORTIONS OF NORTHEAST MINNESOTA AND NORTHERN
WISCONSIN...AND SOME LAKE EFFECT SNOW SHOWERS CONTINUED ALONG THE
SOUTH SHORE. CONDITIONS BECOME LESS FAVORABLE FOR LES TODAY...AS
850MB TEMPERATURES WARM THROUGH THE MORNING WITH DRIER AIR MOVING
OVER LAKE SUPERIOR. WE DON`T EXPECT MUCH ACCUMULATION THIS MORNING
OVER THE SNOWBELT REGION. CLOUD COVER WILL BE A CHALLENGE TODAY. THE
WESTERN EDGE OF THE CLOUDS THIS MORNING WAS MOVING SLOWLY EAST AND
THE CLOUDS APPEAR TO BE DIMINISHING. HOWEVER...THE RAP SUGGESTS
WE`LL SEE SOME REDEVELOPMENT BY LATE MORNING/EARLY AFTERNOON WITH
SOME HEATING. WE DID FOLLOW THAT TREND...AND HAVE PARTLY TO MOSTLY
CLOUDY SKIES GOING FOR ABOUT THE SOUTHERN HALF TO TWO THIRDS OF THE
CWA THROUGH MID AFTERNOON. WE EXPECT HIGHS TODAY TO BE MAINLY IN THE
MID TWENTIES...BUT WILL HAVE TO ADJUST A FEW DEGREES DEPENDING ON
THE EXTENT OF THE CLOUD COVER.
TONIGHT INTO FRIDAY THE NORTHLAND GETS SQUEEZED BETWEEN TWO
TROUGHS...ONE EXTENDING FROM NORTHERN BRITISH COLUMBIA INTO THE
NORTHERN PLAINS...AND THE PERSISTENT EASTERN TROUGH. WE EXPECT
TONIGHT TO BE CLEAR TO PARTLY CLOUDY FOR MOST AREAS WITH LIGHTER
WINDS. WE WENT BELOW MOST OF THE LOW TEMP GUIDANCE TONIGHT...CLOSER
TO THE NHGEMBC. DEEP SNOWPACK...LIGHT WINDS AND MINIMAL CLOUD COVER
SHOULD ALLOW FOR THE COLD TEMPS. THICKER CLOUDS WILL MOVE INTO THE
ARROWHEAD/BORDER REGION LATER TONIGHT...AND THAT WILL KEEP THEM FROM
REALLY GETTING COLD.
FRIDAY WILL BE PARTLY SUNNY WITH HIGHS A BIT WARMER...FROM 28 TO 34
FOR MOST AREAS.
LONG TERM...FRIDAY NIGHT THROUGH THURSDAY.
THE WESTERN LAKE SUPERIOR REGION WILL SITUATED BETWEEN A LARGE CUT
OFF LOW ROTATING OVER THE NEW ENGLAND STATES...AND A DIGGING TROUGH
OVER THE ROCKIES THROUGH THE WEEKEND. THIS WILL RESULT IN WEAK SFC
RIDGING OVER THE CWA FRIDAY NIGHT/SAT. A NORTH TO NORTHEAST FLOW
WILL DEVELOP SAT NIGHT THROUGH SUNDAY AS A VORT MAX WITH SFC
REFLECTION LOW EJECTS OUT OF THE BASE OF THE TROUGH AND TRACKS EAST
ACROSS THE SRN PLAINS. AT THIS TIME...MODELS IN AGREEMENT THAT THE
NRN EXTENT OF ANY PRECIPITATION ASSOCIATED WITH THE WAVE TRANSLATES
ALONG THE SOUTHERN MN/WI STATE LINES. MEANWHILE...AN ELONGATED VORT
MAX BREAKS FREE FROM THE EASTERN LOW...AND RETROGRADES ACROSS
ONTARIO FRIDAY NIGHT...DROPPING INTO THE NRN LAKE SUPERIOR/MN
ARROWHEAD REGION SATURDAY. ATTM...THIS VORT IS EXPECTED TO BRING
PRIMARILY INCREASING CLOUDS. HOWEVER...RH FIELDS AND LATEST NAM BUFR
SOUNDINGS SHOWS INCREASING LOW LEVEL MOISTURE FRI NIGHT THAT
SUGGESTS A SMALL POTENTIAL FOR SOME FOG/BR OR POSSIBLY VERY LIGHT
DZ/SN SAT/SAT NIGHT. HOWEVER...HAVE KEPT FCST DRY THROUGH THE
WEEKEND AS ANY THE PRECIP CHCS ARE VERY SMALL AND QPF WILL BE
ISOLATED AND LIGHT.
BEYOND THE WEEKEND...THE H50 FLOW BECOMES VERY DISORGANIZED AS
MODELS TRY TO RESOLVE PHASING THE DOUBLE LOWS OVER THE ERN COAST.
GENIALLY HAVE KEPT EXTENDED DRY WITH TEMPERATURES NEAR TO A FEW
DEGREES BELOW NORMAL.
&&
.POINT TEMPS/POPS...
DLH 26 -1 31 13 / 10 0 10 10
INL 25 -8 30 9 / 0 0 10 10
BRD 25 -2 32 15 / 10 0 10 10
HYR 27 -5 33 11 / 10 0 10 10
ASX 26 3 31 13 / 10 10 10 10
&&
.DLH WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
&&
$$
AVIATION...GRANING
AREA FORECAST DISCUSSION
NWS OMAHA/VALLEY NE
946 AM CDT THU MAR 21 2013
.DISCUSSION...
HAVE UDPATED THE GRIDS FOR TRENDS WITH THE MORNING SNOW. INCREASED
POPS IN THE FAR SOUTH CWA AS HEAVIER BAND EXITS THE AREA...AND
ALSO EXPANDED POPS IN THE NORTHWEST CWA WHERE VIS IS DOWN TO ABOUT
1 MI WITH SOME SNOW. CONTINUED THE SHARP GRADIENT TO DRY
CONDITIONS IN THE EASTERN CWA...WITH EASTERLY WINDS BRINGING IN
DRY AIR. ADDITIONALLY...HAVE SPED THE EXIT OF THE SYSTEM TODAY AS
LIFT SLIDES TO THE SOUTH...WITH JUST A SMALL AREA OF CHANCE POPS
IN THE FAR SOUTHEAST CORNER OF NEB IN THE EARLY AFTERNOON AND ALL
CLEAR 21-00Z. FINALLY...HAVE TWEAKED TEMPERATURES AND DEWPOINTS
BOTH FOR HOURLY TRENDS AND TO TOUCH DOWN TEMPS A BIT IN THE
SOUTHERN CWA.
MAYES
&&
.PREV DISCUSSION... /ISSUED 616 AM CDT THU MAR 21 2013/
AVIATION...12Z TAFS FOR KOMA...KLNK AND KOFK. WEATHER DISTURBANCE
MOVING THROUGH THE REGION THIS MORNING COULD BRING SOME LIGHT SNOW
AT KLNK AND KOFK...THAT COLD LINGER THROUGH 17-18Z WITH TEMPORARY
MVFR RESTRICTIONS...AND ESPECIALLY AT KLNK. DUE TO PERSISTENT DRY
EASTERLY FLOW AT KOMA...BELIEVE PRECIP MAY NOT REACH THAT FAR
EAST. SURFACE EASTERLY WINDS ALSO INCREASE TO 12 TO 14 KNOTS
TODAY...AND COULD SEE OCCASIONAL GUSTS UP TO 18-20 KNOTS AT
KOFK/KLNK AS WELL.
THERE WILL BE A BREAK IN THE PRECIPITATION WITH VFR CONDITIONS
EXPECTED...HOWEVER ANOTHER WAVE WILL MOVE OFF THE HIGH PLAINS
TONIGHT. THIS WILL LIKELY SPREAD SNOW BACK INTO THE THE KOFK/KLNK
BY 22/05-06Z...AND KOMA BY 22/08Z ALONG WITH MVFR CONDITIONS ONCE
AGAIN. SNOW BEGINS TO TAPER OFF AT KLNK/KOFK BY 28/12...BUT WOULD
LINGER AT KOMA BEYOND THE END OF THIS TAF PERIOD.
DEWALD
PREV DISCUSSION... /ISSUED 337 AM CDT THU MAR 21 2013/
DISCUSSION...
FORECAST CHALLENGES FOR THIS FORECAST PACKAGE WILL INCLUDE TIMING
OF THE SNOW CHANCES TODAY...TONIGHT AND FRIDAY...SATURDAY INTO THE
EXTENDED...WILL IT BE MEASURABLE AND HOW MUCH?...WILL THERE BE
ANY PERIODS OF A MIX?...ALSO TEMPERATURES THROUGH THE PERIOD.
OUR OAX SOUNDING FROM 00Z WAS QUITE DRY WITH SOME HIGHER RH AT H5
AND H85...BUT ONLY 36 PERCENT OF NORMAL PRECIPITABLE WATER. THIS
WAS COMMON ACROSS THE ENTIRE MIDWEST...WITH THE CLOSEST NEAR NORMAL
PRECIPITABLE WATER AT RAPID CITY AND DODGE CITY.
A LOOP OF THE IR SATELLITE IMAGERY SHOWS A LOT GOING ON AND
DIFFERENT FLOWS ACROSS THE COUNTRY. THERE IS A STRONG AREA OF LOW
PRESSURE/WINTER SYSTEM OVER THE NORTHEAST U.S./GREAT LAKES. THE
TROF IN THE PACIFIC NORTHWEST SHOWS UP...AS WELL AS THE FETCH OF
TROPICAL MOISTURE FROM THE PACIFIC ACROSS THE SOUTHERN PLAINS. AT
H85...THE THERMAL GRADIENT SHOWS UP NICELY BETWEEN THE COLD SYSTEM
OFF TO OUR EAST...AND THE WARMER AIR WITH THE PACIFIC SYSTEM THAT
WILL AFFECT US INTO THE WEEKEND WITH -12 DEG C AT OMA AND +1C AT
LBF. AT THE SURFACE....SURFACE HIGH PRESSURE EXTENDED FROM THE
NORTHERN PLAINS THRU THE MISSOURI RIVER VALLEY INTO IOWA AND
MISSOURI. LOCALLY TEMPERATURES WERE IN THE TEENS AND 20S WITH
DEWPOINTS IN THE SINGLE DIGITS AND TEENS. AN AREA OF LOW PRESSURE
EXTENDED FROM WYOMING THROUGH COLORADO. TEMPERATURES WERE MUCH
WARMER IN WESTERN NEBRASKA WITH 30S AND 40S. AT 08Z...A NORTHWEST
TO SOUTHEAST BAND OF ECHOES HAS BEEN INCREASING AND SLIDING EAST. AT
08Z...SNOW WAS REACHING THE GROUND AT ANW AND TIF. HOW DOES THIS
MATCH OF WITH THE PROGS...THE NAM WAS DRY AND THE
SREF/GFS/EC/RAP/HRRR...ALL SHOWED SOME PRECIP IN THIS AREA TO
VARYING DEGREES.
THERE ARE THREE PERIODS WHEN WE MAY SEE LIGHT SNOW.
TODAY...TONIGHT INTO FRIDAY MORNING AND SATURDAY AFTERNOON INTO
SUNDAY...EACH PROGRESSIVELY MORE ORGANIZED.
THIS MORNING...THERE IS STRONG H85 WARM AIR ADVECTION ACROSS
KANSAS WITH A 50KT LOW LEVEL JET AND H7 WAA INTO NEBRASKA. THERE
IS SOME LIFT WITH A WEAK SHORTWAVE IN THE NORTHWEST FLOW...AND A
DECENT INCREASE MOISTURE. ACROSS PARTS OF EASTERN NEBRASKA. LOW
LEVEL DRY AIR IS IN PLACE...SO THE TOUGH CALL WILL BE WHERE TO
INCLUDE POPS...WHERE TO KEEP IT DRY AND IF IT WILL BE MEASURABLE.
IN GENERAL...THE SHORT RANGE MODELS BRING A NARROW BAND OF LIGHT
SNOW ACROSS PARTS OF EASTERN NEBRASKA WITH LITTLE OR NO
ACCUMULATION. THE RAP APPEARS OVERDONE. WILL INCLUDE HIGHEST POPS
IN THE WRN PART OF THE FORECAST AREA AND WILL LEAVE MAINLY DRY
PARTS OF NORTHEAST AND FAR EASTERN NEBRASKA INTO PARTS OF
SOUTHWEST IOWA. CLOUDS OR LACK OF THICKER CLOUDS WILL IMPACT
TEMPERATURES AND HAVE RAISED SOME OF THE HIGHS. HIGHS IN THE 30S
TO LOWER 40S.
TONIGHT AND FRIDAY MORNING LARGE SCALE LIFT OCCURS WITH A PIECE OF
ENERGY FROM THE PACIFIC NORTHWEST STORM SYSTEM ROTATING THROUGH
THE PLAINS WITH LIGHT SNOW SPREADING FROM WESTERN NEBRASKA INTO
EASTERN NEBRASKA TONIGHT AND MORE INTO WESTERN IOWA FRIDAY
MORNING...THEN WEAKENING. THERE COULD BE SOME LIGHT ACCUMULATIONS
AND FOR NOW HAVE MOST AMOUNTS AN INCH OR LESS.
THERE IS A BREAK IN THE PRECIPITATION LATER FRIDAY INTO EARLY
SATURDAY. THE H5 TROF MOVES INTO THE PLAINS SATURDAY/SATURDAY
NIGHT. THE NAM SEEMS TO BE THE OUTLIER WITH A STRONGER FAST CLOSED
LOW THAT TRACKS FARTHER NORTH. FOR NOW TRENDED WITH THE EC/GFS AND
HAVE THE HIGHEST POPS ACROSS THE SOUTHERN HALF OF THE FORECAST
AREA. THE PRECIPITATION SATURDAY COULD START AS A RAIN/SNOW MIX
BEFORE IT CHANGES OVER TO SNOW. THERE IS GOOD WRAP- AROUND
MOISTURE IN THE DENDRITIC LAYER SO THIS WILL NEED TO BE WATCHED.
IT IS EARLY TO PUT AMOUNTS ON THE SAT/SUN STORM AS THE TRACK MAY
SHIFT...THE EC/GFS ARE MORE IN THE 2 TO 6 INCH CATEGORY FOR THE
SOUTHERN HALF OF THE FORECAST AREA WITH THE HEAVY SNOW IN KANSAS
AND MISSOURI. WHILE THE NAM HAS HIGHER AMOUNTS FARTHER NORTH.
HEADLINES WILL NEED TO BE CONSIDERED IF THE SYSTEM DOES NOT TRACK
FARTHER SOUTH DUE TO THE COMBINATION OF BRISK WINDS AND SNOW.
ZAPOTOCNY
&&
.OAX WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
IA...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS HASTINGS NE
641 AM CDT THU MAR 21 2013
.SHORT TERM...(TODAY THROUGH TONIGHT)
ISSUED AT 510 AM CDT THU MAR 21 2013
ALTHOUGH THESE NEXT 24 HOURS DO NOT APPEAR TO PACK THE PUNCH THAT
THE WEEKEND WILL...THERE ARE NONETHELESS TWO DISTURBANCES THAT
WILL MAKE THE IMMEDIATE SHORT TERM QUITE TRICKY...AS THE
FIRST ONE COULD BRING A LIGHT DUSTING OF SNOW/POSSIBLY A BRIEF
SHOT OF SLEET TO PARTS OF THE CWA THIS MORNING...AND THEN A
SOMEWHAT MORE POTENT WAVE TONIGHT COULD BRING ROUGHLY 1 INCH OF
SNOW TO MUCH OF THE CWA...ALONG WITH MAYBE SOME LIGHT FREEZING
DRIZZLE IN ITS WAKE. ALTHOUGH ITS CERTAINLY NOT COMPLETELY OUT OF
THE QUESTION THAT TONIGHT/S EVENT MIGHT CREATE SOME SLICK ROADS
FOR THE FRIDAY MORNING COMMUTE...THE GENERALLY MINOR EXPECTED SNOW
AMOUNTS AND LACK OF CONFIDENCE IN FREEZING DRIZZLE HAVING MUCH
IMPACT PRECLUDES ANY TYPE OF FORMAL WINTER WEATHER ADVISORY AT THIS
TIME...ALTHOUGH WILL CONTINUE TO SUGGEST THE POSSIBILITY OF MINOR
IMPACTS IN THE HAZARDOUS WEATHER OUTLOOK.
09Z OBJECTIVE SURFACE ANALYSIS DEPICTS A BROAD RIDGE AXIS CENTERED
FROM THE EASTERN DAKOTAS THROUGH MO/AR...WHILE TO THE WEST A
MODEST NORTH-SOUTH HIGH PLAINS LEE TROUGH IS IN PLACE. IN BETWEEN
THESE FEATURES...FAIRLY STEADY EAST-SOUTHEAST BREEZES OF 10-20 MPH
WITH SOME HIGHER GUSTS HAVE RAMPED UP ACROSS THE CWA. PRE-DAWN
TEMPERATURES ARE NEAR TO SLIGHTLY HIGHER THAN EARLIER
FORECAST...BUT WILL STILL AIM FOR OVERNIGHT LOWS RANGING FROM LOW-
MID 20S CENTRAL/NORTHEAST TO UPPER 20S/NEAR 30 SOUTHWEST.
ALOFT...WATER VAPOR IMAGERY AND SHORT TERM MODEL DATA DEPICT
PROGRESSIVE WEST-NORTHWEST FLOW ALOFT OVER THE CENTRAL
PLAINS...IN BETWEEN A DEEP LOW OVER THE NORTHEAST CONUS...AND AN
UPSTREAM MID LEVEL SHORTWAVE TROUGH STEADILY APPROACHING THE
REGION FROM THE NORTHERN ROCKIES. ALTHOUGH THE LOCAL AREA IS
TECHNICALLY UNDER A FAIRLY SMALL SCALE AND BROAD SHORTWAVE RIDGE
ALOFT AT THIS TIME...PRONOUNCED ISENTROPIC LIFT EVIDENT ON THE
295K SURFACE WITHIN THE ENTRANCE REGION OF A DEPARTING UPPER LEVEL
JET STREAK IS PROMOTING A STEADILY ORGANIZING NORTHWEST-SOUTHEAST
BAND OF PRECIPITATION ACROSS MAINLY THE NORTHEAST 1/2 OF THE CWA.
SO FAR...THERE HAS BEEN FAIRLY LIMITED GROUND TRUTH OF THIS
PRECIPITATION REACHING THE GROUND...ALTHOUGH A HANDFUL OF
AUTOMATED SENSORS INCLUDING ORD/BROKEN BOW ARE NOW REPORTING LIGHT
SNOW.
FORECAST WISE TODAY...HAVE BROKEN POPS/WEATHER INTO 3-HOUR BLOCKS
THROUGH THE REST OF THIS MORNING...WITH THE HIGHEST 30-50 PERCENT
CHANCES FOR LIGHT MEASURABLE SNOW AND POSSIBLY A BRIEF BIT OF
SLEET FOCUSED NORTHEAST OF A LINE FROM KEARNEY TO SUPERIOR...WHICH
LINES UP QUITE NICELY WITH THE SATURATED 295K SURFACE PER THE 06Z
NAM. THE JURY IS STILL VERY MUCH OUT ON WHETHER THIS PRECIPITATION
WILL BE LEGITIMATE LIGHT MEASURABLE SNOW...OR JUST GLORIFIED
FLURRIES...SO FOR NOW WILL KEEP POPS BELOW LIKELY TERRITORY
BARRING FURTHER EVIDENCE THAT MIGHT SUGGEST AN INCREASE IS
WARRANTED. EVEN IF THE FULL POTENTIAL OF THIS MORNING SNOW BAND IS
REALIZED...WOULD BE FAIRLY SURPRISED TO SEE ANY LOCATION REPORT
MORE THAN ONE-HALF INCH. CLOSELY FOLLOWING REFLECTIVITY TRENDS
FROM HIGHER RES MODELS SUCH AS THE HRRR AND 00Z 4KM
WRF-NMM...ANTICIPATE A GRADUAL EASTWARD SHIFT OF THE SNOW/FLURRY
BAND THIS MORNING...AND LIKELY DEPARTING THE NORTHEAST CWA BY MID-
DAY. ALTHOUGH MAY LATER REGRET THIS MOVE...OPTED TO PULL ALL
MENTION OF PRECIP FROM THE 1PM-7PM AFTERNOON TIME FRAME ACROSS THE
ENTIRE CWA...AS THE INITIAL SNOW BAND SHOULD BE DISSIPATED OR
MOVED OFF TO THE EAST-SOUTHEAST BY THEN...WHILE THE NEXT UPSTREAM
PRECIPITATION CHANCE SHOULD STILL BE JUST OFF TO THE WEST.
ALTHOUGH THE DAY AS A WHOLE SHOULD AVERAGE MOSTLY CLOUDY IN MOST
AREAS...COULD ACTUALLY SEE A FEW HOURS OF PARTIAL SUNSHINE AROUND
MID-DAY IN SOME AREAS IN BETWEEN SYSTEMS. OTHERWISE...THE BIGGEST
CHANGE TO TODAY/S FORECAST INVOLVED A ROUGHLY 5-DEGREE INCREASE TO
HIGH TEMPERATURES IN ALL BUT FAR NORTHEAST AREAS...AS THE LACK OF
AFTERNOON PRECIPITATION AND POTENTIALLY FILTERED SUNSHINE NOW
LOOKS TO HELP BOOST READINGS WELL INTO THE 40S ACROSS THE MAJORITY
OF THE CWA...WITH FAR SOUTHERN/SOUTHWEST AREAS POSSIBLY CRACKING
50. WILL HOWEVER KEEP KEEP THE FAR NORTHEAST AROUND THE
POLK/EASTERN NANCE/YORK COUNTY AREA DOWN IN THE UPPER 30S GIVEN
THE EXPECTATION OF CLOUDS HOLDING FIRMER THERE.
TURNING TO THE NIGHT PERIOD 7PM-7AM...AGAIN TOOK A BEST STAB AT
3-HOUR POP/WX GRIDS. ALTHOUGH POPS WERE RAISED INTO 60 PERCENT
LIKELY RANGE ACROSS MUCH OF THE AREA FOR AT LEAST A PORTION OF THE
NIGHT...ITS VERY POSSIBLE THAT POPS WILL NEED CRANKED UP MORE AS
CONFIDENCE INCREASES IN AT LEAST LIGHT SNOW ACCUMULATIONS.
ALOFT...THE PRIMARY INSTIGATOR IS A PROGRESSIVE...OPEN AND FAIRLY
LOW AMPLITUDE MID LEVEL SHORTWAVE TROUGH SWINGING WEST-EAST ACROSS
THE CENTRAL PLAINS ALONG THE SOUTHEAST PERIPHERY OF ITS PARENT
LARGER SCALE LOW CENTERED OVER THE NORTHERN ROCKIES. ALTHOUGH
THERE ARE STILL PLENTY OF MIXED MESSAGES REGARDING HOW QUICKLY
THIS PRECIPITATION MOVES INTO THE CWA...WITH SOME MODELS
SUGGESTING IT COULD EVEN MOVE INTO FAR WESTERN COUNTIES BEFORE 7
PM...HAVE TRIED TO FOLLOW THE REFLECTIVITY PROG OF THE 00Z WRF-NMM
FAIRLY CLOSELY. AS A RESULT...HAVE FOCUSED THE HIGHEST POPS ACROSS
THE WESTERN 1/2 OF THE CWA PRIOR TO 10 PM...AND THEN BRINGING
INCREASED CHANCES ACROSS THE REMAINDER OF THE AREA
THEREAFTER...AND THEN GRADUALLY DECREASING POPS FROM SOUTHWEST-
NORTHEAST ESPECIALLY BETWEEN 4 AM AND SUNRISE. ALTHOUGH ANTICIPATE
LIGHT TO BRIEFLY MODERATE SNOW TO BE THE MAIN PRECIP-TYPE...OPTED
TO MENTION A RAIN-SNOW MIX EARLY IN THE EVENING TO ACCOUNT FOR
STILL FAIRLY-WARM SURFACE TEMPS. SOME BRIEF SLEET IS NOT OUT OF
THE QUESTION IN SOME PLACES EITHER...BUT OVERALL THIS LOOKS LIKE
MAINLY SNOW AFTER NIGHTFALL AND WILL NOT INSERT ANY SLEET MENTION
AT THIS TIME. BETWEEN MIDNIGHT AND SUNRISE...THERE ARE STILL SOME
VALID CONCERNS FOR LIGHT DRIZZLE/FREEZING DRIZZLE DEVELOPING FOR
AT LEAST A FEW HOURS AS DEEPER MID LEVEL SATURATION MOVES OFF TO
THE EAST WHILE THE LOWEST FEW THOUSAND FEET REMAIN SATURATED PER
LOW LEVEL RELATIVE HUMIDITY PROGS FROM THE NAM. THE NAM ALSO SPITS
OUT ITS TELLTALE LIGHT/BLOTCHY QPF SIGNATURE INDICATIVE OF DRIZZLE
ACROSS MUCH OF THE CWA ESPECIALLY BETWEEN 4AM-7AM. GIVEN THE
EXPECTATION OF CONSIDERABLE CLOUD COVER...LOW TEMPS WERE RAISED A
FEW DEGREES FROM PREVIOUS FORECAST INTO THE MID-UPPER 20S ACROSS
MOST OF THE CWA...AND ITS ENTIRELY POSSIBLE THAT SOME AREAS
ESPECIALLY ACROSS THE SOUTHWESTERN CWA MAY BARELY DROP BELOW
FREEZING DURING THE TIME THAT DRIZZLE COULD FALL...THUS MITIGATING
ANY IMPACTS. THE THINKING AT THIS TIME HOWEVER IS THAT THE SNOW
WILL PROBABLY BE THE BIGGER STORY IMPACT-WISE THAN ANY FREEZING
DRIZZLE LINGERING THEREAFTER. ALTHOUGH CONFIDENCE IN SPECIFIC SNOW
AMOUNTS IS ADMITTEDLY SHAKY...HAVE GENERALLY PAINTED THE
SOUTHWESTERN CWA WITH 0.5 TO 0.9-INCH THROUGH SUNRISE FRIDAY
MORNING...WITH SLIGHTLY HIGHER AMOUNTS OF 1 INCH TO POSSIBLY 1.5
INCHES TARGETING THE NORTHEAST 1/2 OF THE CWA. AGAIN...THIS SETUP
BEARS WATCHING...BUT ITS STILL A TOUGH CALL TO SAY WHETHER THIS
COMBINATION OF LIGHT SNOW ACCUMULATION AND POSSIBLY LIGHT FREEZING
DRIZZLE WILL BE IMPACTFUL ENOUGH TO ULTIMATELY WARRANT A WINTER
WEATHER ADVISORY.
.LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 510 AM CDT THU MAR 21 2013
WE BEGIN FRIDAY WITH FORECAST SOUNDINGS REVEALING A STARK LOSS OF
MID-LEVEL SATURATION...WHICH WILL GIVE US AT LEAST A SMALL CHANCE
OF FREEZING DRIZZLE/DRIZZLE AS THE DENDRITIC GROWTH ZONE SCOOTS
OFF TO THE NORTHEAST/EAST. WE COULD HOLD ON TO A SMALL CHANCE OF
SNOW IN THE NORTHEAST EARLY FRIDAY MORNING...BUT ANY SNOW AMOUNTS
WOULD BE MINIMAL. MEANWHILE...IN THE UPPER LEVELS...A STRONG 140+
JET WILL DIG ON THE BACKSIDE OF A DEVELOPING TROUGH OVER THE
INTERMOUNTAIN WEST. WE SHOULD EXPERIENCE AT LEAST A SHORT LULL
PERIOD FOR FRIDAY AFTERNOON INTO FRIDAY EVENING.
TWO DISTINCT MID-LEVEL CENTERS OF LOW PRESSURE ARE FORECAST TO
DEVELOP WITHIN THE AFOREMENTIONED TROUGH. THERE IS FAIR AGREEMENT
AMONG MODELS THAT BY SATURDAY MORNING...ONE LOW WILL BE NEAR THE
CANADIAN/MONTANA BORDER...AND THE OTHER IN WESTERN COLORADO OR
PERHAPS EASTERN UTAH...ACCORDING TO THE ECMWF. THE NAM KEEPS AN OPEN
WAVE OVER COLORADO...WITH THE CLOSED LOW IN WESTERN NORTH DAKOTA FOR
12Z SATURDAY. THE NAM INDICATES STRONG ISENTROPIC LIFT ON THE 295K
PLANE FOR LATE FRIDAY NIGHT INTO SATURDAY ACROSS THE CWA AHEAD OF
THE TROUGH/LOW...ESPECIALLY IN THE WEST AND SOUTH...SO I INCREASED
CHANCES OF SNOW FOR THIS PERIOD COMPARED TO THE PREVIOUS FORECAST
AND LATEST MODEL GUIDANCE VALUES. THE NAM RAKES THE TROUGH AXIS
ACROSS THE CWA BY SATURDAY LATE AFTERNOON/EVENING...BUT THE ECMWF
TAKES ITS TIME...WITH THE AXIS CROSSING LATE DURING THE OVERNIGHT
SATURDAY NIGHT AND THUS MAXIMIZED LARGE SCALE LIFT...WITH THE GFS IN
BETWEEN...BY THE MID-EVENING. THE TRACK OF THE 500 MB LOW IS
FORECAST ALONG THE SOUTHERN/SOUTHWESTERN PERIPHERY OF OUR CWA...WITH
THE 700 MB JUST TO THE SOUTH OF THE CWA. STILL LOOKS LIKE KANSAS
STANDS THE BETTER CHANCE OF RECEIVING MORE OF THE ACCUMULATING
SNOWFALL THAN THE NEBRASKA SIDE AND HAVE NOT DEVIATED MUCH AT ALL
FROM THE PREVIOUS FORECAST SNOW AMOUNTS. THE QUESTION OF TIMING
KEEPS AT LEAST SMALL CHANCES INTO SUNDAY MORNING...WITH FURTHER
COMPLICATIONS POSSIBLE WITH THE NORTHERN LOW HELPING TO SUBSEQUENT
ENERGY DOWN OUR WAY...AND THE JET STREAM JUST TO THE SOUTH...NOT TO
FAR AWAY.
WITH THE PROBABILITY OF SOME SNOW COVER AND COLD TEMPERATURES ALOFT
FOR SUNDAY...I LOWERED MAXIMUM TEMPERATURES FOR SUNDAY...BELOW
GUIDANCE VALUES.
BELOW NORMAL TEMPERATURES WILL BE THE RULE FOR THE ENTIRE LONG
TERM...WITH YET MORE SMALL CHANCES OF SNOW/RAIN BY WEDNESDAY AS THE
REAR RIGHT QUADRANT OF THE JET STREAK TO THE SOUTH NEARS THE CWA AND
THE NORTHERN LOW HEADS SOUTH AND APPROACHES THE REGION...WHICH IN
TURN...COULD MEAN MORE COOL AND UNSETTLED WEATHER BEYOND THE SCOPE
OF THE LONG TERM FORECAST.
&&
.AVIATION...(FOR THE 12Z KGRI TAF THROUGH 12Z FRIDAY MORNING)
ISSUED AT 630 AM CDT THU MAR 21 2013
ALTHOUGH EXPECT VFR CEILING/VISIBILITY TO PREVAIL THROUGH THE
MAJORITY OF THE PERIOD...DETERIORATING CONDITIONS TO AT LEAST MVFR
LEVELS...IF NOT IFR...ARE EXPECTED TONIGHT MAINLY DURING THE FINAL
8 HOURS OF THE PERIOD. IN ESSENCE...TWO DISTINCT LOW PRESSURE
SYSTEMS WILL AFFECT THE AREA. STARTING OUT RIGHT AWAY THIS MORNING
AND POTENTIALLY LASTING FOR ANOTHER 1-2 HOURS...AN AREA OF LIGHT
SNOW WILL CONTINUE SLIPPING EAST OF THE AREA...WITH A BRIEF MVFR
VISIBILITY RESTRICTION NOT OUT OF THE QUESTION. ONCE THIS SNOW
MOVES OUT...A CONSIDERABLE LULL IN PRECIPITATION WILL TAKE PLACE
THROUGH THE REST OF THE DAY AND INTO THE FIRST PART OF THIS
EVENING...WITH FAIRLY HIGH CONFIDENCE IN VFR CEILING/VISIBILITY
DURING THIS TIME. THEN...STARTING ROUGHLY AROUND 04Z AND LASTING
THROUGH THE REST OF THE NIGHT...A MORE ROBUST CHANCE OF LIGHT TO
POTENTIALLY MODERATE MEASURABLE SNOW WILL MOVE IN FROM THE
WEST...WITH TOTAL ACCUMULATION BY FRIDAY MORNING FORECAST AROUND 1
INCH. SOME LIGHT FREEZING DRIZZLE COULD EVEN MIX WITH OR REPLACE
LIGHT SNOW AFTER ROUGHLY 09Z. ALTHOUGH IFR CONDITIONS ARE
CERTAINLY POSSIBLY IN FALLING SNOW TONIGHT...WILL KEEP IT LOW-END
MVFR FOR NOW AND LET LATER SHIFTS ADJUST AS THE PICTURE BECOMES
CLEARER. AS FOR SURFACE WINDS...THEY WILL REMAIN FAIRLY CONSISTENT
IN DIRECTION FROM THE EAST-SOUTHEAST THROUGH THE PERIOD...WITH
SUSTAINED SPEEDS GENERALLY FLUCTUATING BETWEEN 12-16KT TODAY INTO
THIS EVENING...BUT WITH SEVERAL HOURS OF GUST POTENTIAL TO AROUND
23KT TODAY BEFORE EASING UP TONIGHT.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
KS...NONE.
&&
$$
SHORT TERM...PFANNKUCH
LONG TERM...HEINLEIN
AVIATION...PFANNKUCH
AREA FORECAST DISCUSSION
NWS OMAHA/VALLEY NE
616 AM CDT THU MAR 21 2013
.AVIATION...12Z TAFS FOR KOMA...KLNK AND KOFK. WEATHER DISTURBANCE
MOVING THROUGH THE REGION THIS MORNING COULD BRING SOME LIGHT SNOW
AT KLNK AND KOFK...THAT COLD LINGER THROUGH 17-18Z WITH TEMPORARY
MVFR RESTRICTIONS...AND ESPECIALLY AT KLNK. DUE TO PERSISTENT DRY
EASTERLY FLOW AT KOMA...BELIEVE PRECIP MAY NOT REACH THAT FAR
EAST. SURFACE EASTERLY WINDS ALSO INCREASE TO 12 TO 14 KNOTS
TODAY...AND COULD SEE OCCASIONAL GUSTS UP TO 18-20 KNOTS AT
KOFK/KLNK AS WELL.
THERE WILL BE A BREAK IN THE PRECIPITATION WITH VFR CONDITIONS
EXPECTED...HOWEVER ANOTHER WAVE WILL MOVE OFF THE HIGH PLAINS
TONIGHT. THIS WILL LIKELY SPREAD SNOW BACK INTO THE THE KOFK/KLNK
BY 22/05-06Z...AND KOMA BY 22/08Z ALONG WITH MVFR CONDITIONS ONCE
AGAIN. SNOW BEGINS TO TAPER OFF AT KLNK/KOFK BY 28/12...BUT WOULD
LINGER AT KOMA BEYOND THE END OF THIS TAF PERIOD.
DEWALD
&&
.PREV DISCUSSION... /ISSUED 337 AM CDT THU MAR 21 2013/
DISCUSSION...
FORECAST CHALLENGES FOR THIS FORECAST PACKAGE WILL INCLUDE TIMING
OF THE SNOW CHANCES TODAY...TONIGHT AND FRIDAY...SATURDAY INTO THE
EXTENDED...WILL IT BE MEASURABLE AND HOW MUCH?...WILL THERE BE
ANY PERIODS OF A MIX?...ALSO TEMPERATURES THROUGH THE PERIOD.
OUR OAX SOUNDING FROM 00Z WAS QUITE DRY WITH SOME HIGHER RH AT H5
AND H85...BUT ONLY 36 PERCENT OF NORMAL PRECIPITABLE WATER. THIS
WAS COMMON ACROSS THE ENTIRE MIDWEST...WITH THE CLOSEST NEAR NORMAL
PRECIPITABLE WATER AT RAPID CITY AND DODGE CITY.
A LOOP OF THE IR SATELLITE IMAGERY SHOWS A LOT GOING ON AND
DIFFERENT FLOWS ACROSS THE COUNTRY. THERE IS A STRONG AREA OF LOW
PRESSURE/WINTER SYSTEM OVER THE NORTHEAST U.S./GREAT LAKES. THE
TROF IN THE PACIFIC NORTHWEST SHOWS UP...AS WELL AS THE FETCH OF
TROPICAL MOISTURE FROM THE PACIFIC ACROSS THE SOUTHERN PLAINS. AT
H85...THE THERMAL GRADIENT SHOWS UP NICELY BETWEEN THE COLD SYSTEM
OFF TO OUR EAST...AND THE WARMER AIR WITH THE PACIFIC SYSTEM THAT
WILL AFFECT US INTO THE WEEKEND WITH -12 DEG C AT OMA AND +1C AT
LBF. AT THE SURFACE....SURFACE HIGH PRESSURE EXTENDED FROM THE
NORTHERN PLAINS THRU THE MISSOURI RIVER VALLEY INTO IOWA AND
MISSOURI. LOCALLY TEMPERATURES WERE IN THE TEENS AND 20S WITH
DEWPOINTS IN THE SINGLE DIGITS AND TEENS. AN AREA OF LOW PRESSURE
EXTENDED FROM WYOMING THROUGH COLORADO. TEMPERATURES WERE MUCH
WARMER IN WESTERN NEBRASKA WITH 30S AND 40S. AT 08Z...A NORTHWEST
TO SOUTHEAST BAND OF ECHOES HAS BEEN INCREASING AND SLIDING EAST. AT
08Z...SNOW WAS REACHING THE GROUND AT ANW AND TIF. HOW DOES THIS
MATCH OF WITH THE PROGS...THE NAM WAS DRY AND THE
SREF/GFS/EC/RAP/HRRR...ALL SHOWED SOME PRECIP IN THIS AREA TO
VARYING DEGREES.
THERE ARE THREE PERIODS WHEN WE MAY SEE LIGHT SNOW.
TODAY...TONIGHT INTO FRIDAY MORNING AND SATURDAY AFTERNOON INTO
SUNDAY...EACH PROGRESSIVELY MORE ORGANIZED.
THIS MORNING...THERE IS STRONG H85 WARM AIR ADVECTION ACROSS
KANSAS WITH A 50KT LOW LEVEL JET AND H7 WAA INTO NEBRASKA. THERE
IS SOME LIFT WITH A WEAK SHORTWAVE IN THE NORTHWEST FLOW...AND A
DECENT INCREASE MOISTURE. ACROSS PARTS OF EASTERN NEBRASKA. LOW
LEVEL DRY AIR IS IN PLACE...SO THE TOUGH CALL WILL BE WHERE TO
INCLUDE POPS...WHERE TO KEEP IT DRY AND IF IT WILL BE MEASURABLE.
IN GENERAL...THE SHORT RANGE MODELS BRING A NARROW BAND OF LIGHT
SNOW ACROSS PARTS OF EASTERN NEBRASKA WITH LITTLE OR NO
ACCUMULATION. THE RAP APPEARS OVERDONE. WILL INCLUDE HIGHEST POPS
IN THE WRN PART OF THE FORECAST AREA AND WILL LEAVE MAINLY DRY
PARTS OF NORTHEAST AND FAR EASTERN NEBRASKA INTO PARTS OF
SOUTHWEST IOWA. CLOUDS OR LACK OF THICKER CLOUDS WILL IMPACT
TEMPERATURES AND HAVE RAISED SOME OF THE HIGHS. HIGHS IN THE 30S
TO LOWER 40S.
TONIGHT AND FRIDAY MORNING LARGE SCALE LIFT OCCURS WITH A PIECE OF
ENERGY FROM THE PACIFIC NORTHWEST STORM SYSTEM ROTATING THROUGH
THE PLAINS WITH LIGHT SNOW SPREADING FROM WESTERN NEBRASKA INTO
EASTERN NEBRASKA TONIGHT AND MORE INTO WESTERN IOWA FRIDAY
MORNING...THEN WEAKENING. THERE COULD BE SOME LIGHT ACCUMULATIONS
AND FOR NOW HAVE MOST AMOUNTS AN INCH OR LESS.
THERE IS A BREAK IN THE PRECIPITATION LATER FRIDAY INTO EARLY
SATURDAY. THE H5 TROF MOVES INTO THE PLAINS SATURDAY/SATURDAY
NIGHT. THE NAM SEEMS TO BE THE OUTLIER WITH A STRONGER FAST CLOSED
LOW THAT TRACKS FARTHER NORTH. FOR NOW TRENDED WITH THE EC/GFS AND
HAVE THE HIGHEST POPS ACROSS THE SOUTHERN HALF OF THE FORECAST
AREA. THE PRECIPITATION SATURDAY COULD START AS A RAIN/SNOW MIX
BEFORE IT CHANGES OVER TO SNOW. THERE IS GOOD WRAP- AROUND
MOISTURE IN THE DENDRITIC LAYER SO THIS WILL NEED TO BE WATCHED.
IT IS EARLY TO PUT AMOUNTS ON THE SAT/SUN STORM AS THE TRACK MAY
SHIFT...THE EC/GFS ARE MORE IN THE 2 TO 6 INCH CATEGORY FOR THE
SOUTHERN HALF OF THE FORECAST AREA WITH THE HEAVY SNOW IN KANSAS
AND MISSOURI. WHILE THE NAM HAS HIGHER AMOUNTS FARTHER NORTH.
HEADLINES WILL NEED TO BE CONSIDERED IF THE SYSTEM DOES NOT TRACK
FARTHER SOUTH DUE TO THE COMBINATION OF BRISK WINDS AND SNOW.
ZAPOTOCNY
&&
.OAX WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
IA...NONE.
&&
$$
AREA FORECAST DISCUSSION...CORRECTED
NWS HASTINGS NE
514 AM CDT THU MAR 21 2013
.SHORT TERM...(TODAY THROUGH TONIGHT)
ISSUED AT 510 AM CDT THU MAR 21 2013
ALTHOUGH THESE NEXT 24 HOURS DO NOT APPEAR TO PACK THE PUNCH THAT
THE WEEKEND WILL...THERE ARE NONETHELESS TWO DISTURBANCES THAT
WILL MAKE THE IMMEDIATE SHORT TERM QUITE TRICKY...AS THE
FIRST ONE COULD BRING A LIGHT DUSTING OF SNOW/POSSIBLY A BRIEF
SHOT OF SLEET TO PARTS OF THE CWA THIS MORNING...AND THEN A
SOMEWHAT MORE POTENT WAVE TONIGHT COULD BRING ROUGHLY 1 INCH OF
SNOW TO MUCH OF THE CWA...ALONG WITH MAYBE SOME LIGHT FREEZING
DRIZZLE IN ITS WAKE. ALTHOUGH ITS CERTAINLY NOT COMPLETELY OUT OF
THE QUESTION THAT TONIGHT/S EVENT MIGHT CREATE SOME SLICK ROADS
FOR THE FRIDAY MORNING COMMUTE...THE GENERALLY MINOR EXPECTED SNOW
AMOUNTS AND LACK OF CONFIDENCE IN FREEZING DRIZZLE HAVING MUCH
IMPACT PRECLUDES ANY TYPE OF FORMAL WINTER WEATHER ADVISORY AT THIS
TIME...ALTHOUGH WILL CONTINUE TO SUGGEST THE POSSIBILITY OF MINOR
IMPACTS IN THE HAZARDOUS WEATHER OUTLOOK.
09Z OBJECTIVE SURFACE ANALYSIS DEPICTS A BROAD RIDGE AXIS CENTERED
FROM THE EASTERN DAKOTAS THROUGH MO/AR...WHILE TO THE WEST A
MODEST NORTH-SOUTH HIGH PLAINS LEE TROUGH IS IN PLACE. IN BETWEEN
THESE FEATURES...FAIRLY STEADY EAST-SOUTHEAST BREEZES OF 10-20 MPH
WITH SOME HIGHER GUSTS HAVE RAMPED UP ACROSS THE CWA. PRE-DAWN
TEMPERATURES ARE NEAR TO SLIGHTLY HIGHER THAN EARLIER
FORECAST...BUT WILL STILL AIM FOR OVERNIGHT LOWS RANGING FROM LOW-
MID 20S CENTRAL/NORTHEAST TO UPPER 20S/NEAR 30 SOUTHWEST.
ALOFT...WATER VAPOR IMAGERY AND SHORT TERM MODEL DATA DEPICT
PROGRESSIVE WEST-NORTHWEST FLOW ALOFT OVER THE CENTRAL
PLAINS...IN BETWEEN A DEEP LOW OVER THE NORTHEAST CONUS...AND AN
UPSTREAM MID LEVEL SHORTWAVE TROUGH STEADILY APPROACHING THE
REGION FROM THE NORTHERN ROCKIES. ALTHOUGH THE LOCAL AREA IS
TECHNICALLY UNDER A FAIRLY SMALL SCALE AND BROAD SHORTWAVE RIDGE
ALOFT AT THIS TIME...PRONOUNCED ISENTROPIC LIFT EVIDENT ON THE
295K SURFACE WITHIN THE ENTRANCE REGION OF A DEPARTING UPPER LEVEL
JET STREAK IS PROMOTING A STEADILY ORGANIZING NORTHWEST-SOUTHEAST
BAND OF PRECIPITATION ACROSS MAINLY THE NORTHEAST 1/2 OF THE CWA.
SO FAR...THERE HAS BEEN FAIRLY LIMITED GROUND TRUTH OF THIS
PRECIPITATION REACHING THE GROUND...ALTHOUGH A HANDFUL OF
AUTOMATED SENSORS INCLUDING ORD/BROKEN BOW ARE NOW REPORTING LIGHT
SNOW.
FORECAST WISE TODAY...HAVE BROKEN POPS/WEATHER INTO 3-HOUR BLOCKS
THROUGH THE REST OF THIS MORNING...WITH THE HIGHEST 30-50 PERCENT
CHANCES FOR LIGHT MEASURABLE SNOW AND POSSIBLY A BRIEF BIT OF
SLEET FOCUSED NORTHEAST OF A LINE FROM KEARNEY TO SUPERIOR...WHICH
LINES UP QUITE NICELY WITH THE SATURATED 295K SURFACE PER THE 06Z
NAM. THE JURY IS STILL VERY MUCH OUT ON WHETHER THIS PRECIPITATION
WILL BE LEGITIMATE LIGHT MEASURABLE SNOW...OR JUST GLORIFIED
FLURRIES...SO FOR NOW WILL KEEP POPS BELOW LIKELY TERRITORY
BARRING FURTHER EVIDENCE THAT MIGHT SUGGEST AN INCREASE IS
WARRANTED. EVEN IF THE FULL POTENTIAL OF THIS MORNING SNOW BAND IS
REALIZED...WOULD BE FAIRLY SURPRISED TO SEE ANY LOCATION REPORT
MORE THAN ONE-HALF INCH. CLOSELY FOLLOWING REFLECTIVITY TRENDS
FROM HIGHER RES MODELS SUCH AS THE HRRR AND 00Z 4KM
WRF-NMM...ANTICIPATE A GRADUAL EASTWARD SHIFT OF THE SNOW/FLURRY
BAND THIS MORNING...AND LIKELY DEPARTING THE NORTHEAST CWA BY MID-
DAY. ALTHOUGH MAY LATER REGRET THIS MOVE...OPTED TO PULL ALL
MENTION OF PRECIP FROM THE 1PM-7PM AFTERNOON TIME FRAME ACROSS THE
ENTIRE CWA...AS THE INITIAL SNOW BAND SHOULD BE DISSIPATED OR
MOVED OFF TO THE EAST-SOUTHEAST BY THEN...WHILE THE NEXT UPSTREAM
PRECIPITATION CHANCE SHOULD STILL BE JUST OFF TO THE WEST.
ALTHOUGH THE DAY AS A WHOLE SHOULD AVERAGE MOSTLY CLOUDY IN MOST
AREAS...COULD ACTUALLY SEE A FEW HOURS OF PARTIAL SUNSHINE AROUND
MID-DAY IN SOME AREAS IN BETWEEN SYSTEMS. OTHERWISE...THE BIGGEST
CHANGE TO TODAY/S FORECAST INVOLVED A ROUGHLY 5-DEGREE INCREASE TO
HIGH TEMPERATURES IN ALL BUT FAR NORTHEAST AREAS...AS THE LACK OF
AFTERNOON PRECIPITATION AND POTENTIALLY FILTERED SUNSHINE NOW
LOOKS TO HELP BOOST READINGS WELL INTO THE 40S ACROSS THE MAJORITY
OF THE CWA...WITH FAR SOUTHERN/SOUTHWEST AREAS POSSIBLY CRACKING
50. WILL HOWEVER KEEP KEEP THE FAR NORTHEAST AROUND THE
POLK/EASTERN NANCE/YORK COUNTY AREA DOWN IN THE UPPER 30S GIVEN
THE EXPECTATION OF CLOUDS HOLDING FIRMER THERE.
TURNING TO THE NIGHT PERIOD 7PM-7AM...AGAIN TOOK A BEST STAB AT
3-HOUR POP/WX GRIDS. ALTHOUGH POPS WERE RAISED INTO 60 PERCENT
LIKELY RANGE ACROSS MUCH OF THE AREA FOR AT LEAST A PORTION OF THE
NIGHT...ITS VERY POSSIBLE THAT POPS WILL NEED CRANKED UP MORE AS
CONFIDENCE INCREASES IN AT LEAST LIGHT SNOW ACCUMULATIONS.
ALOFT...THE PRIMARY INSTIGATOR IS A PROGRESSIVE...OPEN AND FAIRLY
LOW AMPLITUDE MID LEVEL SHORTWAVE TROUGH SWINGING WEST-EAST ACROSS
THE CENTRAL PLAINS ALONG THE SOUTHEAST PERIPHERY OF ITS PARENT
LARGER SCALE LOW CENTERED OVER THE NORTHERN ROCKIES. ALTHOUGH
THERE ARE STILL PLENTY OF MIXED MESSAGES REGARDING HOW QUICKLY
THIS PRECIPITATION MOVES INTO THE CWA...WITH SOME MODELS
SUGGESTING IT COULD EVEN MOVE INTO FAR WESTERN COUNTIES BEFORE 7
PM...HAVE TRIED TO FOLLOW THE REFLECTIVITY PROG OF THE 00Z WRF-NMM
FAIRLY CLOSELY. AS A RESULT...HAVE FOCUSED THE HIGHEST POPS ACROSS
THE WESTERN 1/2 OF THE CWA PRIOR TO 10 PM...AND THEN BRINGING
INCREASED CHANCES ACROSS THE REMAINDER OF THE AREA
THEREAFTER...AND THEN GRADUALLY DECREASING POPS FROM SOUTHWEST-
NORTHEAST ESPECIALLY BETWEEN 4 AM AND SUNRISE. ALTHOUGH ANTICIPATE
LIGHT TO BRIEFLY MODERATE SNOW TO BE THE MAIN PRECIP-TYPE...OPTED
TO MENTION A RAIN-SNOW MIX EARLY IN THE EVENING TO ACCOUNT FOR
STILL FAIRLY-WARM SURFACE TEMPS. SOME BRIEF SLEET IS NOT OUT OF
THE QUESTION IN SOME PLACES EITHER...BUT OVERALL THIS LOOKS LIKE
MAINLY SNOW AFTER NIGHTFALL AND WILL NOT INSERT ANY SLEET MENTION
AT THIS TIME. BETWEEN MIDNIGHT AND SUNRISE...THERE ARE STILL SOME
VALID CONCERNS FOR LIGHT DRIZZLE/FREEZING DRIZZLE DEVELOPING FOR
AT LEAST A FEW HOURS AS DEEPER MID LEVEL SATURATION MOVES OFF TO
THE EAST WHILE THE LOWEST FEW THOUSAND FEET REMAIN SATURATED PER
LOW LEVEL RELATIVE HUMIDITY PROGS FROM THE NAM. THE NAM ALSO SPITS
OUT ITS TELLTALE LIGHT/BLOTCHY QPF SIGNATURE INDICATIVE OF DRIZZLE
ACROSS MUCH OF THE CWA ESPECIALLY BETWEEN 4AM-7AM. GIVEN THE
EXPECTATION OF CONSIDERABLE CLOUD COVER...LOW TEMPS WERE RAISED A
FEW DEGREES FROM PREVIOUS FORECAST INTO THE MID-UPPER 20S ACROSS
MOST OF THE CWA...AND ITS ENTIRELY POSSIBLE THAT SOME AREAS
ESPECIALLY ACROSS THE SOUTHWESTERN CWA MAY BARELY DROP BELOW
FREEZING DURING THE TIME THAT DRIZZLE COULD FALL...THUS MITIGATING
ANY IMPACTS. THE THINKING AT THIS TIME HOWEVER IS THAT THE SNOW
WILL PROBABLY BE THE BIGGER STORY IMPACT-WISE THAN ANY FREEZING
DRIZZLE LINGERING THEREAFTER. ALTHOUGH CONFIDENCE IN SPECIFIC SNOW
AMOUNTS IS ADMITTEDLY SHAKY...HAVE GENERALLY PAINTED THE
SOUTHWESTERN CWA WITH 0.5 TO 0.9-INCH THROUGH SUNRISE FRIDAY
MORNING...WITH SLIGHTLY HIGHER AMOUNTS OF 1 INCH TO POSSIBLY 1.5
INCHES TARGETING THE NORTHEAST 1/2 OF THE CWA. AGAIN...THIS SETUP
BEARS WATCHING...BUT ITS STILL A TOUGH CALL TO SAY WHETHER THIS
COMBINATION OF LIGHT SNOW ACCUMULATION AND POSSIBLY LIGHT FREEZING
DRIZZLE WILL BE IMPACTFUL ENOUGH TO ULTIMATELY WARRANT A WINTER
WEATHER ADVISORY.
.LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 510 AM CDT THU MAR 21 2013
WE BEGIN FRIDAY WITH FORECAST SOUNDINGS REVEALING A STARK LOSS OF
MID-LEVEL SATURATION...WHICH WILL GIVE US AT LEAST A SMALL CHANCE
OF FREEZING DRIZZLE/DRIZZLE AS THE DENDRITIC GROWTH ZONE SCOOTS
OFF TO THE NORTHEAST/EAST. WE COULD HOLD ON TO A SMALL CHANCE OF
SNOW IN THE NORTHEAST EARLY FRIDAY MORNING...BUT ANY SNOW AMOUNTS
WOULD BE MINIMAL. MEANWHILE...IN THE UPPER LEVELS...A STRONG 140+
JET WILL DIG ON THE BACKSIDE OF A DEVELOPING TROUGH OVER THE
INTERMOUNTAIN WEST. WE SHOULD EXPERIENCE AT LEAST A SHORT LULL
PERIOD FOR FRIDAY AFTERNOON INTO FRIDAY EVENING.
TWO DISTINCT MID-LEVEL CENTERS OF LOW PRESSURE ARE FORECAST TO
DEVELOP WITHIN THE AFOREMENTIONED TROUGH. THERE IS FAIR AGREEMENT
AMONG MODELS THAT BY SATURDAY MORNING...ONE LOW WILL BE NEAR THE
CANADIAN/MONTANA BORDER...AND THE OTHER IN WESTERN COLORADO OR
PERHAPS EASTERN UTAH...ACCORDING TO THE ECMWF. THE NAM KEEPS AN OPEN
WAVE OVER COLORADO...WITH THE CLOSED LOW IN WESTERN NORTH DAKOTA FOR
12Z SATURDAY. THE NAM INDICATES STRONG ISENTROPIC LIFT ON THE 295K
PLANE FOR LATE FRIDAY NIGHT INTO SATURDAY ACROSS THE CWA AHEAD OF
THE TROUGH/LOW...ESPECIALLY IN THE WEST AND SOUTH...SO I INCREASED
CHANCES OF SNOW FOR THIS PERIOD COMPARED TO THE PREVIOUS FORECAST
AND LATEST MODEL GUIDANCE VALUES. THE NAM RAKES THE TROUGH AXIS
ACROSS THE CWA BY SATURDAY LATE AFTERNOON/EVENING...BUT THE ECMWF
TAKES ITS TIME...WITH THE AXIS CROSSING LATE DURING THE OVERNIGHT
SATURDAY NIGHT AND THUS MAXIMIZED LARGE SCALE LIFT...WITH THE GFS IN
BETWEEN...BY THE MID-EVENING. THE TRACK OF THE 500 MB LOW IS
FORECAST ALONG THE SOUTHERN/SOUTHWESTERN PERIPHERY OF OUR CWA...WITH
THE 700 MB JUST TO THE SOUTH OF THE CWA. STILL LOOKS LIKE KANSAS
STANDS THE BETTER CHANCE OF RECEIVING MORE OF THE ACCUMULATING
SNOWFALL THAN THE NEBRASKA SIDE AND HAVE NOT DEVIATED MUCH AT ALL
FROM THE PREVIOUS FORECAST SNOW AMOUNTS. THE QUESTION OF TIMING
KEEPS AT LEAST SMALL CHANCES INTO SUNDAY MORNING...WITH FURTHER
COMPLICATIONS POSSIBLE WITH THE NORTHERN LOW HELPING TO SUBSEQUENT
ENERGY DOWN OUR WAY...AND THE JET STREAM JUST TO THE SOUTH...NOT TO
FAR AWAY.
WITH THE PROBABILITY OF SOME SNOW COVER AND COLD TEMPERATURES ALOFT
FOR SUNDAY...I LOWERED MAXIMUM TEMPERATURES FOR SUNDAY...BELOW
GUIDANCE VALUES.
BELOW NORMAL TEMPERATURES WILL BE THE RULE FOR THE ENTIRE LONG
TERM...WITH YET MORE SMALL CHANCES OF SNOW/RAIN BY WEDNESDAY AS THE
REAR RIGHT QUADRANT OF THE JET STREAK TO THE SOUTH NEARS THE CWA AND
THE NORTHERN LOW HEADS SOUTH AND APPROACHES THE REGION...WHICH IN
TURN...COULD MEAN MORE COOL AND UNSETTLED WEATHER BEYOND THE SCOPE
OF THE LONG TERM FORECAST.
&&
.AVIATION...(FOR THE 06Z KGRI TAF THROUGH 06Z THURSDAY NIGHT)
ISSUED AT 1253 AM CDT THU MAR 21 2013
ALTHOUGH EXPECT VFR CEILING/VISIBILITY TO PREVAIL THROUGH THE VAST
MAJORITY OF THE PERIOD...THERE ARE TWO DISTINCT OPPORTUNITIES FOR
AT LEAST LIGHT SNOW ACCUMULATION...THE SECOND OF WHICH LATE IN THE
PERIOD IS LOOKING MORE IMPACTFUL WITH MVFR CEILING/VISIBILITY OR
WORSE. STARTING OFF DURING THE FIRST 8 HOURS OF THE PERIOD THIS
MORNING...HAVE MAINTAINED A LIGHT SNOW POSSIBILITY BUT TWEAKED IT
SLIGHTLY TO FOCUS BETWEEN 10Z-14Z...AND ALSO RAISED VISIBILITY TO
VFR LEVELS AS ANTICIPATE THIS PRECIPITATION TO BE FAIRLY
LIGHT...IF IF EVEN AFFECTS KGRI AT ALL. ALTHOUGH A LOW VFR CEILING
IS POSSIBLE THROUGH AT LEAST MUCH OF THE MORNING HOURS...WOULD BE
FAIRLY SURPRISED TO SEE IT DROP INTO MVFR. FOLLOWING A CONSIDERABLE
LULL IN PRECIPITATION POTENTIAL LATE THIS MORNING INTO THIS
EVENING...THE NEXT AND LIKELY BETTER CHANCE OF MEASURABLE SNOW
ARRIVES DURING THE LAST FEW HOURS OF THE PERIOD THURSDAY
NIGHT...BUT AS A STARTING POINT WILL SHOW NO WORSE THAN MVFR
CEILING/VISIBILITY. AS FOR SURFACE WINDS...THEY WILL REMAIN FAIRLY
CONSISTENT IN DIRECTION FROM THE EAST-SOUTHEAST THROUGH THE
PERIOD...WITH SUSTAINED SPEEDS GENERALLY FLUCTUATING BETWEEN
10-16KT...BUT WITH SEVERAL HOURS OF GUST POTENTIAL TO AT LEAST
22KT MAINLY DURING THE DAYTIME HOURS.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
KS...NONE.
&&
$$
SHORT TERM...PFANNKUCH
LONG TERM...HEINLEIN
AVIATION...PFANNKUCH
AREA FORECAST DISCUSSION
NWS HASTINGS NE
511 AM CDT THU MAR 21 2013
.SHORT TERM...(TODAY THROUGH TONIGHT)
ISSUED AT 510 AM CDT THU MAR 21 2013
ALTHOUGH THESE NEXT 24 HOURS DO NOT APPEAR TO PACK THE PUNCH THAT
THE WEEKEND WILL...THERE ARE NONETHELESS TWO DISTURBANCES THAT
WILL MAKE THE IMMEDIATE SHORT TERM QUITE TRICKY...AS THE
FIRST ONE COULD BRING A LIGHT DUSTING OF SNOW/POSSIBLY A BRIEF
SHOT OF SLEET TO PARTS OF THE CWA THIS MORNING...AND THEN A
SOMEWHAT MORE POTENT WAVE TONIGHT COULD BRING ROUGHLY 1 INCH OF
SNOW TO MUCH OF THE CWA...ALONG WITH MAYBE SOME LIGHT FREEZING
DRIZZLE IN ITS WAKE. ALTHOUGH ITS CERTAINLY NOT COMPLETELY OUT OF
THE QUESTION THAT TONIGHT/S EVENT MIGHT CREATE SOME SLICK ROADS
FOR THE FRIDAY MORNING COMMUTE...THE GENERALLY MINOR EXPECTED SNOW
AMOUNTS AND LACK OF CONFIDENCE IN FREEZING DRIZZLE HAVING MUCH
IMPACT PRECLUDES ANY TYPE OF FORMAL WINTER WEATHER ADVISORY AT THIS
TIME...ALTHOUGH WILL CONTINUE TO SUGGEST THE POSSIBILITY OF MINOR
IMPACTS IN THE HAZARDOUS WEATHER OUTLOOK.
09Z OBJECTIVE SURFACE ANALYSIS DEPICTS A BROAD RIDGE AXIS CENTERED
FROM THE EASTERN DAKOTAS THROUGH MO/AR...WHILE TO THE WEST A
MODEST NORTH-SOUTH HIGH PLAINS LEE TROUGH IS IN PLACE. IN BETWEEN
THESE FEATURES...FAIRLY STEADY EAST-SOUTHEAST BREEZES OF 10-20 MPH
WITH SOME HIGHER GUSTS HAVE RAMPED UP ACROSS THE CWA. PRE-DAWN
TEMPERATURES ARE NEAR TO SLIGHTLY HIGHER THAN EARLIER
FORECAST...BUT WILL STILL AIM FOR OVERNIGHT LOWS RANGING FROM LOW-
MID 20S CENTRAL/NORTHEAST TO UPPER 20S/NEAR 30 SOUTHWEST.
ALOFT...WATER VAPOR IMAGERY AND SHORT TERM MODEL DATA DEPICT
PROGRESSIVE WEST-NORTHWEST FLOW ALOFT OVER THE CENTRAL
PLAINS...IN BETWEEN A DEEP LOW OVER THE NORTHEAST CONUS...AND AN
UPSTREAM MID LEVEL SHORTWAVE TROUGH STEADILY APPROACHING THE
REGION FROM THE NORTHERN ROCKIES. ALTHOUGH THE LOCAL AREA IS
TECHNICALLY UNDER A FAIRLY SMALL SCALE AND BROAD SHORTWAVE RIDGE
ALOFT AT THIS TIME...PRONOUNCED ISENTROPIC LIFT EVIDENT ON THE
295K SURFACE WITHIN THE ENTRANCE REGION OF A DEPARTING UPPER LEVEL
JET STREAK IS PROMOTING A STEADILY ORGANIZING NORTHWEST-SOUTHEAST
BAND OF PRECIPITATION ACROSS MAINLY THE NORTHEAST 1/2 OF THE CWA.
SO FAR...THERE HAS BEEN FAIRLY LIMITED GROUND TRUTH OF THIS
PRECIPITATION REACHING THE GROUND...ALTHOUGH A HANDFUL OF
AUTOMATED SENSORS INCLUDING ORD/BROKEN BOW ARE NOW REPORTING LIGHT
SNOW.
FORECAST WISE TODAY...HAVE BROKEN POPS/WEATHER INTO 3-HOUR BLOCKS
THROUGH THE REST OF THIS MORNING...WITH THE HIGHEST 30-50 PERCENT
CHANCES FOR LIGHT MEASURABLE SNOW AND POSSIBLY A BRIEF BIT OF
SLEET FOCUSED NORTHEAST OF A LINE FROM KEARNEY TO SUPERIOR...WHICH
LINES UP QUITE NICELY WITH THE SATURATED 295K SURFACE PER THE 06Z
NAM. THE JURY IS STILL VERY MUCH OUT ON WHETHER THIS PRECIPITATION
WILL BE LEGITIMATE LIGHT MEASURABLE SNOW...OR JUST GLORIFIED
FLURRIES...SO FOR NOW WILL KEEP POPS BELOW LIKELY TERRITORY
BARRING FURTHER EVIDENCE THAT MIGHT SUGGEST AN INCREASE IS
WARRANTED. EVEN IF THE FULL POTENTIAL OF THIS MORNING SNOW BAND IS
REALIZED...WOULD BE FAIRLY SURPRISED TO SEE ANY LOCATION REPORT
MORE THAN ONE-HALF INCH. CLOSELY FOLLOWING REFLECTIVITY TRENDS
FROM HIGHER RES MODELS SUCH AS THE HRRR AND 00Z 4KM
WRF-NMM...ANTICIPATE A GRADUAL EASTWARD SHIFT OF THE SNOW/FLURRY
BAND THIS MORNING...AND LIKELY DEPARTING THE NORTHEAST CWA BY MID-
DAY. ALTHOUGH MAY LATER REGRET THIS MOVE...OPTED TO PULL ALL
MENTION OF PRECIP FROM THE 1PM-7PM AFTERNOON TIME FRAME ACROSS THE
ENTIRE CWA...AS THE INITIAL SNOW BAND SHOULD BE DISSIPATED OR
MOVED OFF TO THE EAST-SOUTHEAST BY THEN...WHILE THE NEXT UPSTREAM
PRECIPITATION CHANCE SHOULD STILL BE JUST OFF TO THE WEST.
ALTHOUGH THE DAY AS A WHOLE SHOULD AVERAGE MOSTLY CLOUDY IN MOST
AREAS...COULD ACTUALLY SEE A FEW HOURS OF PARTIAL SUNSHINE AROUND
MID-DAY IN SOME AREAS IN BETWEEN SYSTEMS. OTHERWISE...THE BIGGEST
CHANGE TO TODAY/S FORECAST INVOLVED A ROUGHLY 5-DEGREE INCREASE TO
HIGH TEMPERATURES IN ALL BUT FAR NORTHEAST AREAS...AS THE LACK OF
AFTERNOON PRECIPITATION AND POTENTIALLY FILTERED SUNSHINE NOW
LOOKS TO HELP BOOST READINGS WELL INTO THE 40S ACROSS THE MAJORITY
OF THE CWA...WITH FAR SOUTHERN/SOUTHWEST AREAS POSSIBLY CRACKING
50. WILL HOWEVER KEEP KEEP THE FAR NORTHEAST AROUND THE
POLK/EASTERN NANCE/YORK COUNTY AREA DOWN IN THE UPPER 30S GIVEN
THE EXPECTATION OF CLOUDS HOLDING FIRMER THERE.
TURNING TO THE NIGHT PERIOD 7PM-7AM...AGAIN TOOK A BEST STAB AT
3-HOUR POP/WX GRIDS. ALTHOUGH POPS WERE RAISED INTO 60 PERCENT
LIKELY RANGE ACROSS MUCH OF THE AREA FOR AT LEAST A PORTION OF THE
NIGHT...ITS VERY POSSIBLE THAT POPS WILL NEED CRANKED UP MORE AS
CONFIDENCE INCREASES IN AT LEAST LIGHT SNOW ACCUMULATIONS.
ALOFT...THE PRIMARY INSTIGATOR IS A PROGRESSIVE...OPEN AND FAIRLY
LOW AMPLITUDE MID LEVEL SHORTWAVE TROUGH SWINGING WEST-EAST ACROSS
THE CENTRAL PLAINS ALONG THE SOUTHEAST PERIPHERY OF ITS PARENT
LARGER SCALE LOW CENTERED OVER THE NORTHERN ROCKIES. ALTHOUGH
THERE ARE STILL PLENTY OF MIXED MESSAGES REGARDING HOW QUICKLY
THIS PRECIPITATION MOVES INTO THE CWA...WITH SOME MODELS
SUGGESTING IT COULD EVEN MOVE INTO FAR WESTERN COUNTIES BEFORE 7
PM...HAVE TRIED TO FOLLOW THE REFLECTIVITY PROG OF THE 00Z WRF-NMM
FAIRLY CLOSELY. AS A RESULT...HAVE FOCUSED THE HIGHEST POPS ACROSS
THE WESTERN 1/2 OF THE CWA PRIOR TO 10 PM...AND THEN BRINGING
INCREASED CHANCES ACROSS THE REMAINDER OF THE AREA
THEREAFTER...AND THEN GRADUALLY DECREASING POPS FROM SOUTHWEST-
NORTHEAST ESPECIALLY BETWEEN 4 AM AND SUNRISE. ALTHOUGH ANTICIPATE
LIGHT TO BRIEFLY MODERATE SNOW TO BE THE MAIN PRECIP-TYPE...OPTED
TO MENTION A RAIN-SNOW MIX EARLY IN THE EVENING TO ACCOUNT FOR
STILL FAIRLY-WARM SURFACE TEMPS. SOME BRIEF SLEET IS NOT OUT OF
THE QUESTION IN SOME PLACES EITHER...BUT OVERALL THIS LOOKS LIKE
MAINLY SNOW AFTER NIGHTFALL AND WILL NOT INSERT ANY SLEET MENTION
AT THIS TIME. BETWEEN MIDNIGHT AND SUNRISE...THERE ARE STILL SOME
VALID CONCERNS FOR LIGHT DRIZZLE/FREEZING DRIZZLE DEVELOPING FOR
AT LEAST A FEW HOURS AS DEEPER MID LEVEL SATURATION MOVES OFF TO
THE EAST WHILE THE LOWEST FEW THOUSAND FEET REMAIN SATURATED PER
LOW LEVEL RELATIVE HUMIDITY PROGS FROM THE NAM. THE NAM ALSO SPITS
OUT ITS TELLTALE LIGHT/BLOTCHY QPF SIGNATURE INDICATIVE OF DRIZZLE
ACROSS MUCH OF THE CWA ESPECIALLY BETWEEN 4AM-7AM. GIVEN THE
EXPECTATION OF CONSIDERABLE CLOUD COVER...LOW TEMPS WERE RAISED A
FEW DEGREES FROM PREVIOUS FORECAST INTO THE MID-UPPER 20S ACROSS
MOST OF THE CWA...AND ITS ENTIRELY POSSIBLE THAT SOME AREAS
ESPECIALLY ACROSS THE SOUTHWESTERN CWA MAY BARELY DROP BELOW
FREEZING DURING THE TIME THAT DRIZZLE COULD FALL...THUS MITIGATING
ANY IMPACTS. THE THINKING AT THIS TIME HOWEVER IS THAT THE SNOW
WILL PROBABLY BE THE BIGGER STORY IMPACT-WISE THAN ANY FREEZING
DRIZZLE LINGERING THEREAFTER. ALTHOUGH CONFIDENCE IN SPECIFIC SNOW
AMOUNTS IS ADMITTEDLY SHAKY...HAVE GENERALLY PAINTED THE
SOUTHWESTERN CWA WITH 0.5 TO 0.9-INCH THROUGH SUNRISE FRIDAY
MORNING...WITH SLIGHTLY HIGHER AMOUNTS OF 1 INCH TO POSSIBLY 1.5
INCHES TARGETING THE NORTHEAST 1/2 OF THE CWA. AGAIN...THIS SETUP
BEARS WATCHING...BUT ITS STILL A TOUGH CALL TO SAY WHETHER THIS
COMBINATION OF LIGHT SNOW ACCUMULATION AND POSSIBLY LIGHT FREEZING
DRIZZLE WILL BE IMPACTFUL ENOUGH TO ULTIMATELY WARRANT A WINTER
WEATHER ADVISORY.
.LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 510 AM CDT THU MAR 21 2013
WE BEGIN MONDAY WITH FORECAST SOUNDINGS REVEALING A STARK LOSS OF
MID-LEVEL SATURATION...WHICH WILL GIVE US AT LEAST A SMALL CHANCE OF
FREEZING DRIZZLE/DRIZZLE AS THE DENDRITIC GROWTH ZONE SCOOTS OFF TO
THE NORTHEAST/EAST. WE COULD HOLD ON TO A SMALL CHANCE OF SNOW IN
THE NORTHEAST EARLY FRIDAY MORNING...BUT ANY SNOW AMOUNTS WOULD BE
MINIMAL. MEANWHILE...IN THE UPPER LEVELS...A STRONG 140+ JET WILL
DIG ON THE BACKSIDE OF A DEVELOPING TROUGH OVER THE INTERMOUNTAIN
WEST. WE SHOULD EXPERIENCE AT LEAST A SHORT LULL PERIOD FOR FRIDAY
AFTERNOON INTO FRIDAY EVENING.
TWO DISTINCT MID-LEVEL CENTERS OF LOW PRESSURE ARE FORECAST TO
DEVELOP WITHIN THE AFOREMENTIONED TROUGH. THERE IS FAIR AGREEMENT
AMONG MODELS THAT BY SATURDAY MORNING...ONE LOW WILL BE NEAR THE
CANADIAN/MONTANA BORDER...AND THE OTHER IN WESTERN COLORADO OR
PERHAPS EASTERN UTAH...ACCORDING TO THE ECMWF. THE NAM KEEPS AN OPEN
WAVE OVER COLORADO...WITH THE CLOSED LOW IN WESTERN NORTH DAKOTA FOR
12Z SATURDAY. THE NAM INDICATES STRONG ISENTROPIC LIFT ON THE 295K
PLANE FOR LATE FRIDAY NIGHT INTO SATURDAY ACROSS THE CWA AHEAD OF
THE TROUGH/LOW...ESPECIALLY IN THE WEST AND SOUTH...SO I INCREASED
CHANCES OF SNOW FOR THIS PERIOD COMPARED TO THE PREVIOUS FORECAST
AND LATEST MODEL GUIDANCE VALUES. THE NAM RAKES THE TROUGH AXIS
ACROSS THE CWA BY SATURDAY LATE AFTERNOON/EVENING...BUT THE ECMWF
TAKES ITS TIME...WITH THE AXIS CROSSING LATE DURING THE OVERNIGHT
SATURDAY NIGHT AND THUS MAXIMIZED LARGE SCALE LIFT...WITH THE GFS IN
BETWEEN...BY THE MID-EVENING. THE TRACK OF THE 500 MB LOW IS
FORECAST ALONG THE SOUTHERN/SOUTHWESTERN PERIPHERY OF OUR CWA...WITH
THE 700 MB JUST TO THE SOUTH OF THE CWA. STILL LOOKS LIKE KANSAS
STANDS THE BETTER CHANCE OF RECEIVING MORE OF THE ACCUMULATING
SNOWFALL THAN THE NEBRASKA SIDE AND HAVE NOT DEVIATED MUCH AT ALL
FROM THE PREVIOUS FORECAST SNOW AMOUNTS. THE QUESTION OF TIMING
KEEPS AT LEAST SMALL CHANCES INTO SUNDAY MORNING...WITH FURTHER
COMPLICATIONS POSSIBLE WITH THE NORTHERN LOW HELPING TO SUBSEQUENT
ENERGY DOWN OUR WAY...AND THE JET STREAM JUST TO THE SOUTH...NOT TO
FAR AWAY.
WITH THE PROBABILITY OF SOME SNOW COVER AND COLD TEMPERATURES ALOFT
FOR SUNDAY...I LOWERED MAXIMUM TEMPERATURES FOR SUNDAY...BELOW
GUIDANCE VALUES.
BELOW NORMAL TEMPERATURES WILL BE THE RULE FOR THE ENTIRE LONG
TERM...WITH YET MORE SMALL CHANCES OF SNOW/RAIN BY WEDNESDAY AS THE
REAR RIGHT QUADRANT OF THE JET STREAK TO THE SOUTH NEARS THE CWA AND
THE NORTHERN LOW HEADS SOUTH AND APPROACHES THE REGION...WHICH IN
TURN...COULD MEAN MORE COOL AND UNSETTLED WEATHER BEYOND THE SCOPE
OF THE LONG TERM FORECAST.
&&
.AVIATION...(FOR THE 06Z KGRI TAF THROUGH 06Z THURSDAY NIGHT)
ISSUED AT 1253 AM CDT THU MAR 21 2013
ALTHOUGH EXPECT VFR CEILING/VISIBILITY TO PREVAIL THROUGH THE VAST
MAJORITY OF THE PERIOD...THERE ARE TWO DISTINCT OPPORTUNITIES FOR
AT LEAST LIGHT SNOW ACCUMULATION...THE SECOND OF WHICH LATE IN THE
PERIOD IS LOOKING MORE IMPACTFUL WITH MVFR CEILING/VISIBILITY OR
WORSE. STARTING OFF DURING THE FIRST 8 HOURS OF THE PERIOD THIS
MORNING...HAVE MAINTAINED A LIGHT SNOW POSSIBILITY BUT TWEAKED IT
SLIGHTLY TO FOCUS BETWEEN 10Z-14Z...AND ALSO RAISED VISIBILITY TO
VFR LEVELS AS ANTICIPATE THIS PRECIPITATION TO BE FAIRLY
LIGHT...IF IF EVEN AFFECTS KGRI AT ALL. ALTHOUGH A LOW VFR CEILING
IS POSSIBLE THROUGH AT LEAST MUCH OF THE MORNING HOURS...WOULD BE
FAIRLY SURPRISED TO SEE IT DROP INTO MVFR. FOLLOWING A CONSIDERABLE
LULL IN PRECIPITATION POTENTIAL LATE THIS MORNING INTO THIS
EVENING...THE NEXT AND LIKELY BETTER CHANCE OF MEASURABLE SNOW
ARRIVES DURING THE LAST FEW HOURS OF THE PERIOD THURSDAY
NIGHT...BUT AS A STARTING POINT WILL SHOW NO WORSE THAN MVFR
CEILING/VISIBILITY. AS FOR SURFACE WINDS...THEY WILL REMAIN FAIRLY
CONSISTENT IN DIRECTION FROM THE EAST-SOUTHEAST THROUGH THE
PERIOD...WITH SUSTAINED SPEEDS GENERALLY FLUCTUATING BETWEEN
10-16KT...BUT WITH SEVERAL HOURS OF GUST POTENTIAL TO AT LEAST
22KT MAINLY DURING THE DAYTIME HOURS.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
KS...NONE.
&&
$$
SHORT TERM...PFANNKUCH
LONG TERM...HEINLEIN
AVIATION...PFANNKUCH
AREA FORECAST DISCUSSION
NWS RALEIGH NC
1033 AM EDT THU MAR 21 2013
.SYNOPSIS...
COLD HIGH PRESSURE WILL BUILD INTO THE REGION FROM THE NORTHWEST
TODAY THROUGH FRIDAY. A COMPLEX LOW PRESSURE SYSTEM WILL DEVELOP
OVER THE DEEP SOUTH ON SATURDAY...THEN TRACK NORTHEAST INTO THE
CAROLINAS AND MID ATLANTIC ON SUNDAY.
&&
.NEAR TERM /THROUGH FRIDAY NIGHT/...
AS OF 1030 AM THURSDAY...
SHORTWAVE ENERGY ROUNDING THE BASE OF AN UNSEASONABLY COLD CYCLONIC
GYRE (CENTERED OVER NEW ENGLAND AND THE LOWER GREAT LAKES) WILL
TRACK EAST FROM THE VIRGINIAS INTO THE DELMARVA THROUGH 18Z THIS
AFTERNOON. DESPITE LOW-LEVEL COLD ADVECTION AND A DRY BOUNDARY
LAYER...DPVA ASSOCIATED WITH THE AFOREMENTIONED SHORTWAVE ENERGY AND
WEAK MID-LEVEL FRONTOGENESIS HAS CONTRIBUTED TO THE DEVELOPMENT OF
LIGHT BANDED PRECIPITATION OVER SOUTHERN VA NEAR THE NC/VA BORDER IN
VICINITY OF THE I-85 CORRIDOR. RAP PROXIMITY SOUNDINGS INDICATE THAT
THERMAL PROFILES ARE SUPPORTIVE OF SNOW WHERE SATURATION EXTENDS
INTO THE ICE NUCLEATION ZONE...IN AGREEMENT WITH THE LATEST
OBSERVATIONAL DATA ACROSS SOUTHERN VA WHERE SEVERAL SITES HAVE
REPORTED LIGHT SNOW. ALTHOUGH THE BOUNDARY LAYER IS SLIGHTLY WARMER
IN THE NORTHERN PIEDMONT AND NE COASTAL PLAIN IN COMPARISON TO
SOUTHERN VA...WETBULB PROFILES REMAIN SUPPORTIVE OF A CHANCE FOR
SNOW WHERE PRECIP IS OF SUFFICIENT INTENSITY TO MOISTEN THE
LOWER-LEVELS AND ONGOING COLD ADVECTION WILL SERVE TO LIMIT THE
EFFECTS OF DIURNAL HEATING. WITH THE ABOVE IN MIND...EXPECT A CHANCE
OF SNOW OR RAIN/SNOW SHOWERS ACROSS THE NORTHERN PIEDMONT AND
NORTHEAST COASTAL PLAIN THROUGH 16-18Z THIS AFTERNOON. GIVEN STRONG
CAA/DEEP MIXING (UP TO 800-850 MB) IN THE PRESENCE OF AN ATYPICALLY
COLD LOW-LEVEL AIRMASS CHARACTERIZED BY H85 TEMPS RANGING FROM -7C
(SOUTH) TO -12C (NORTH)...EXPECT HIGHS TODAY TO RANGE FROM THE UPPER
30S /NEAR 40F/ NEAR THE VA BORDER TO THE MID/UPPER 40S NEAR THE SC
BORDER. -VINCENT
FOR TONIGHT: WINDS SHOULD DIMINISH QUICKLY BY EARLY EVENING WITH THE
LOOSENING MSLP GRADIENT AS THE SURFACE RIDGE EXPANDS OVER THE
CAROLINAS FROM THE NW. WE MAY SEE A FEW HIGH CLOUDS IN THE LEE OFF
THE SRN APPALACHIANS OVER THE SWRN PIEDMONT TOWARD MORNING WITH THE
400 MB FRONTAL ZONE SHIFTING BACK TO THE NNE INTO NC. OTHERWISE...
EXPECT CLEAR SKIES. GUIDANCE TRENDS AND THICKNESSES SUPPORT LOWS OF
22-27. FORECAST LOWS AT GSO (24) AND RDU (24) ARE WITHIN A COUPLE
DEGREES OF RECORD LOWS FOR MARCH 22 (BOTH RECORDS ARE 22 LAST SET IN
1986). FAY`S LOW (FORECAST OF 26 AND RECORD LOW OF 22 SET IN 1956)
APPEARS SAFE.
FOR FRIDAY/FRIDAY NIGHT: A PORTION OF THE SURFACE RIDGE EXTENDING
THROUGH THE CAROLINAS FROM THE NW BREAKS OFF OVER THE SOUTHEAST
COAST... RESULTING IN NW AND WNW WINDS SWINGING AROUND TO
SOUTHWESTERLY BUT REMAINING LIGHT. THE FRONTAL ZONE LOCATED ALONG FL
AND THE NORTHERN GULF TODAY WILL START TO HEAD BACK NORTH AND NNE AS
A WARM FRONT... DRIVEN BY AN APPROACHING TROUGH AND FALLING HEIGHTS
OVER THE DESERT SOUTHWEST AND LOWERING SURFACE PRESSURES OVER TX.
EXPECT PLENTY OF SUNSHINE THROUGH MUCH OF FRIDAY WITH DEEP DRY AND
STABLE AIR IN PLACE... THEN INCREASING ISENTROPIC UPGLIDE FROM THE
SW SHOULD RESULT IN QUICKLY INCREASING AND THICKENING CLOUDS FRIDAY
EVENING AND NIGHT AS HIGHER PRECIP WATER (150% OF NORMAL) SPREADS
INTO NC FROM THE SSW. OVERALL FORCING FOR ASCENT REMAINS MUTED...
AND THE COLUMN DOES NOT COMPLETELY SATURATE ACCORDING TO GFS/NAM
FORECAST SOUNDINGS... BUT THE GFS DEPICTS FAIRLY STRONG MOIST
UPGLIDE AT 295-310K BY 12Z SATURDAY SUCH IT PRODUCES ONE TO TWO
TENTHS OF AN INCH OF PRECIP OVER THE SRN CWA. EVEN THE NAM HAS A 30
KT SWRLY LOW LEVEL JET NOSING INTO THE NORTHWARD-RETREATING WARM
FRONT AS IT HEADS INTO SRN NC. WILL BRING IN A SMALL CHANCE OF RAIN
OVER THE SW AND FAR SRN CWA LATE FRIDAY NIGHT. THE LOW LEVEL TEMP
PROFILE SUPPORTS AN UPWARD NUDGE TO HIGHS... TO 52-55 DEGREES. THIS
IS ON THE COOL SIDE OF STATISTICAL GUIDANCE AND MAY STILL BE TOO
COOL IF GUIDANCE TRENDS ARE CORRECT. LOWS 32-39. -GIH
&&
.SHORT TERM /SATURDAY/...
AS OF 300 AM THURSDAY...
STRONG HIGH LATITUDE BLOCKING DOWNSTREAM AND THE NEGATIVE ARCTIC
OSCILLATION WILL CONTINUE THROUGH EARLY NEXT WEEK...KEEPING
TEMPERATURES BELOW NORMAL THROUGH THE SHORT AND LONG TERM. WEAK
DISTURBANCES MOVING OUT OF THE SOUTHERN ROCKIES WILL MOVE EAST ON A
SUPPRESSED...SOUTHERN STORM TRACK WITH THE POLAR FRONT DRAPED ACROSS
THE NORTHERN GOMEX. A MORE SUBSTANTIAL SHORTWAVE IS FORECAST TO
EMERGE ACROSS THE SOUTHERN PLAINS SUNDAY AND TRACK GENERALLY
EAST-NORTHEAST NEAR THE OH/TN VALLEYS...LEADING TO A MILLER-B
SURFACE LOW EVOLUTION AND HYBRID COLD AIR DAMMING SUNDAY. AHEAD OF
THIS WAVE...STRENGTHENING SOUTHERLY FLOW AND WARM ADVECTION SHOULD
SPREAD SOME LIGHT PRECIP ACROSS THE SOUTHEAST US EARLY SATURDAY AS
THE 850MB FRONT LIFTS NORTH ACROSS AL/GA/SC. HOWEVER..MODELS
CONTINUE TO DISAGREE ON THE NORTHWARD EXTENT OF MEASURABLE PRECIP.
THE GFS AND NAM HAVE BEEN THE MOST AGGRESSIVE WITH MOISTURE
RETURN AND ISENTROPIC LIFT...BUT GIVEN HOW DRY THE ANTECEDENT
AIRMASS IS EXPECTED TO BE THURSDAY AND FRIDAY...PREFER TO STICK WITH
THE ECMWF WHICH SHOWS MEASURABLE PRECIP ONLY CONFINED TO THE
SOUTHERN CWA AT BEST DURING THE DAY SATURDAY. BECAUSE OF THE
UNCERTAINTY IN PRECIP COVERAGE...HIGHS ARE TRICKY AS WELL. COOL AND
DRY HIGH PRESSURE WILL LINGER OVER THE AREA..BUT UNLESS THERE IS
PRECIP EARLY IN THE DAY...SOME SUN MAY BE POSSIBLE ACROSS THE
NORTHERN PORTIONS OF THE AREA. THE LATEST GUIDANCE IS HIGHER THAN
IN PREVIOUS RUNS...BUT PREFER TO STAY ON THE COOLER SIDE OF GUIDANCE
GIVE THE UNCERTAINTY. WILL INDICATE HIGHS FAIRLY UNIFORM IN THE
49-51 DEGREE RANGE.
&&
.LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/...
AS OF 300 AM THURSDAY...
THE SHORTWAVE AND ASSOCIATED SURFACE LOW(S) MENTIONED IN THE SHORT
TERM DISCUSSION ABOVE ARE FORECAST TO LIFT ACROSS THE TN VALLEY AND
NC/VA SATURDAY NIGHT AND SUNDAY. MODELS CONTINUE TO CONVERGE TOWARD
THIS TIMING AND TRACK...AND THUS FORECAST CONFIDENCE IS INCREASING.
ISENTROPIC ASCENT ATOP THE DEVELOPING HYBRID COLD AIR DAMMING
AIRMASS SHOULD BE MAXIMIZED EARLY SUNDAY...WITH THE SHOT OF DPVA AND
THE ARRIVAL OF A DRY SLOT BY SUNDAY EVENING. A SURFACE LOW IS THEN
EXPECTED TO DEVELOP OFF THE CAROLINA COAST SUNDAY NIGHT. MODELS
CURRENTLY PROJECT THE 850MB LOW TO TRACK ACROSS VA...AND WITHOUT A
STRONG PARENT HIGH TO OUR NORTH...CRITICAL THICKNESSES SHOULD REMAIN
ABOVE 1310/1550M...SUGGESTING JUST A COLD RAIN AREAWIDE SUNDAY. IT
SHOULD BE NOTED THAT SOME EARLY MODEL RUNS HAD SHOWN A MORE SOUTHERN
TRACK OF THE MID LEVEL LOW AND LOWER THICKNESSES...SO MODEL TRENDS
WILL CONTINUE TO BE MONITORED GIVEN THAT WINTRY PRECIP MAY BE
POSSIBLE JUST TO OUR NORTH. HIGHS SUNDAY WILL BE AS MUCH AS 20-25
DEGREES BELOW NORMAL IN THE 40S.
PRECIP WILL LIKELY END AS DRIZZLE MONDAY NIGHT WHILE THE FLOW TURNS
TO WESTERLY IN THE WAKE OF THE DEPARTING LOW PRESSURE SYSTEM. A
GENERAL CLEARING TREND IS EXPECTED INTO EARLY NEXT WEEK WITH
WEST-NORTHWESTERLY FLOW AS THE UPPER LOW OVER THE NORTHERN ATLANTIC
PERSISTS. THE PATTERN DOES NOT LOOK TO CHANGE THROUGH MID TO LATE
WEEK...AND BELOW NORMAL TEMPERATURES SHOULD CONTINUE.
&&
.AVIATION /12Z THURSDAY THROUGH MONDAY/...
AS OF 740 AM THURSDAY...
VFR CONDITIONS WILL DOMINATE THROUGH TONIGHT.
A COLD FRONT WILL SHIFT OFF THE NC COAST THIS MORNING. BEHIND THE
FRONT... WINDS FROM THE NW (290-320 DEGREES) AROUND 15 KTS WILL GUST
TO 25-30 KTS THROUGH THIS AFTERNOON... WITH SCT-BKN CLOUDS BASED AT
OR ABOVE 5 THOUSAND FT AGL. WINDS WILL DISSIPATE AFTER 22Z WITH
SKIES BECOMING UNLIMITED AS CHILLY HIGH PRESSURE BUILDS IN.
LOOKING BEYOND 12Z FRIDAY... VFR CONDITIONS WILL HOLD THROUGH FRIDAY
NIGHT. THERE IS A GOOD CHANCE OF MVFR CIGS SATURDAY AS A COMPLEX
STORM SYSTEM MOVES INTO THE REGION FROM THE WSW. THESE ARE LIKELY TO
WORSEN TO IFR SATURDAY NIGHT AND PERSIST THROUGH SUNDAY NIGHT. SMALL
IMPROVEMENT TO MVFR CIGS IS POSSIBLE MONDAY AS THE STORM SLOWLY
DEPARTS. -GIH
&&
.FIRE WEATHER...
FOLLOWING YESTERDAY`S COORDINATION WITH THE NCFS... WILL CONTINUE
WITH A STATEMENT FOR INCREASED FIRE DANGER FOR TODAY. DESPITE THE
CHILLY TEMPS TODAY... WITH DEW POINTS DROPPING INTO THE LOW TEENS
AND SINGLE DIGITS... THE RELATIVE HUMIDITY IS EXPECTED TO BOTTOM OUT
AT 20-25 PERCENT... AND SUSTAINED WINDS OF 15-20 MPH ARE EXPECTED TO
GUST TO 25-30 MPH. SCANT RAINFALL OF LATE AND FAIRLY LOW FUEL
MOISTURE WILL EXACERBATE THE THREAT OF ADVERSE FIRE BEHAVIOR. -GIH
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...VINCENT
NEAR TERM...VINCENT/HARTFIELD
SHORT TERM...BLS
LONG TERM...BLS
AVIATION...HARTFIELD
FIRE WEATHER...HARTFIELD
AREA FORECAST DISCUSSION
NWS SIOUX FALLS SD
1013 AM CDT THU MAR 21 2013
.UPDATE...
ISSUED AT 1013 AM CDT THU MAR 21 2013
VIRGA ECHOES STILL PREVAILING ACROSS THE SOUTHWEST CWA...HOWEVER
WITH WINNER REPORTING LIGHT SNOW WITH 4SM VSBY LAST HOUR...OPTED
TO ADD A MENTION OF FLURRIES AS WEAKENING SHORT WAVE LINGERS
THROUGH REMAINDER OF MORNING AND EARLY AFTERNOON. ALSO DELAYED
ONSET OF PRECIP ACROSS THE WEST WITH SECONDARY SHORT WAVE TO ENTER
AFTER 00Z THIS EVENING. 12Z NAM AND LATEST HRRR SHOWING DRY
CONDITIONS UNTIL CLOSER TO 03Z IN THE WEST AND SOUNDINGS STILL
SHOWING DRY LAYER THAT WILL TAKE TIME TO SATURATE. OTHERWISE
FORECAST LOOKS ON TRACK.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 342 AM CDT THU MAR 21 2013
CURRENTLY...VIRGA ECHOES ARE EVIDENT RIGHT ON THE SOUTHWEST CORNER
OF OUR FORECAST AREA. THIS ACTIVITY IS ASSOCIATED WITH A WEAK MID
LEVEL SHORT WAVE SITUATED IN WESTERN SD AND WESTERN NE...AND WILL
DRIFT SOUTHEASTWARD EARLY THIS MORNING GENERALLY AWAY FROM OUR
AREA. ISENTROPIC LIFT IS PRETTY STRONG WITH THIS WAVE TO THE
SOUTHWEST...COUPLED WITH SOME THETA E ADVECTION. BUT LOW LEVELS
ARE MOISTURE STARVED. THEREFORE DID NOT PUT ANY POPS IN GREGORY
COUNTY FOR EARLY TODAY. OTHERWISE THE REST OF THE DAY IS PRETTY
MUCH WHAT YOU SEE IS WHAT YOU GET. MOST OF THE CLOUDINESS WILL
REMAIN BOTTLED UP IN OUR WESTERN ZONES...WITH CLEARING SKIES
HEADING EASTWARD FROM THERE. IT WILL BE ANOTHER CHILLY DAY WITH
TEMPERATURES WELL BELOW NORMAL...WITH A COOL EASTERLY FETCH OF AIR
NOT HELPING THINGS ANY. MODELS HAVE GREATLY SLOWED THE ONSLAUGHT
OF PRECIPITATION POTENTIAL. WITH SOME MISGIVINGS...KEPT LOW POPS
GOING IN OUR EXTREME WESTERN ZONES NEAR CHAMBERLAIN...BUT WOULD
NOT BE SURPRISED IF NOTHING HAPPENED THERE BEFORE 00Z FRIDAY. IF
LIGHT PRECIPITATION WOULD HAPPEN TO OCCUR...KEPT THE TYPE AS LIGHT
SNOW EVEN THOUGH SURFACE TEMPERATURES LATE TODAY ARE IN THE UPPER
30S ACROSS THOSE LOCATIONS. AIR MASS IS SUB ZERO AT 850MB AND
SURFACE DEW POINTS ARE NOT REAL HIGH ALLOWING FOR SOME WET BULBING
AFFECT.
TONIGHT...THE CRUX OF A SECOND SHORT WAVE MOVES EASTWARD INTO OUR
FORECAST AREA...MOVING ALONG THE SOUTHERN END OF A LARGE UPPER
TROUGH SITUATED THROUGHOUT WESTERN CANADA AND THE NORTHWEST UNITED
STATES. THE 00Z NAM/GFS/UKMET/GEM ARE ALL IN EXCELLENT AGREEMENT
WITH THE TIMING OF THE SHORT WAVE AND THE SUBSEQUENT SATURATION OF
THE PROFILE. HOWEVER...ISENTROPIC LIFT IS DECIDEDLY WEAKER IN THE
MID LEVELS WHEN COMPARED TO YESTERDAYS MODELS FOR OUR FORECAST AREA.
FURTHERMORE...THE 00Z ECMWF HAS JUST COME IN KEEPING THE
PRECIPITATION POTENTIAL JUST WEST OF THE I 29 CORRIDOR FOR THE
ENTIRE NIGHT. THIS CONFLICTS WITH MY GOING POPS WHICH WAS A SUPER
ENSEMBLE BLEND OF THE AFOREMENTIONED MODELS. THE SLOWER ECMWF IS
BOTHERSOME...IN THAT IT WAS THE ONLY MODEL YESTERDAY WHICH KEPT
OUR FORECAST AREA DRY FOR TODAY. SO IF THE FORECAST IS IN ERROR
TONIGHT...IT WILL LIKELY BE TO KEEP THE LIGHT SNOWFALL MORE TO THE
WEST OF I 29. SOMETHING TO WATCH FOR...FOR THE UPCOMING DAY SHIFT.
AT ANY RATE...CATEGORICAL POPS ARE CERTAINLY WARRANTED MAINLY
ALONG AND WEST OF THE JAMES RIVER VALLEY...WITH RAPIDLY DECREASING
POPS EASTWARD FROM THERE. A COUPLE OF INCHES OF SNOW COULD FALL
AROUND THE CHAMBERLAIN AREA TONIGHT...WITH MAYBE AN INCH OR SO IN
THE JAMES RIVER VALLEY...TAPERING OFF TO THE EAST. CONCERNING
LOWS...THERE WILL LIKELY BE A LARGE DISCREPANCY IN TEMPERATURES
FROM WEST TO EAST. GREGORY COUNTY WITH THEIR CLOUD COVER WILL PROBABLY
STAY AROUND 25 DEGREES. CONVERSELY...SOUTHWEST MN AND THE SPENCER
IA LOCATIONS WILL LIKELY DIP BELOW 10 DEGREES AGAIN WITH MUCH
CLEARER SKIES. LOWS ARE THE TRICKIEST ALONG THE I 29 CORRIDOR...
WHO IS CAUGHT ON WHAT COULD BE THE EDGE OF SOME THICKER CLOUD
COVER FOR AT LEAST PART OF THE NIGHT.
.LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 342 AM CDT THU MAR 21 2013
ANOTHER SEASONABLY CHILLY DAY ON FRIDAY IS CERTAIN. THURSDAY
NIGHTS SHORT WAVE EXITS OUR EASTERN ZONES ABOUT MIDDAY...WHICH
SHOULD BRING AN END TO THE SNOWFALL POTENTIAL IN OUR FORECAST AREA
BY MID AFTERNOON. THEN IT IS JUST WAITING FOR THE NEXT...MORE
SIGNIFICANT UPPER TROUGH TO DIG DOWN THE SPINE OF THE ROCKIES
FRIDAY NIGHT AND SATURDAY. THE WAVE THEN MOVES ACROSS THE CENTRAL
PLAINS FOR THE REMAINDER OF THE WEEKEND. THE SNOWFALL POTENTIAL IS
GOING TO HAVE A HECK OF A TIME MAKING IT NORTHWARD INTO OUR
FORECAST AREA LATE FRIDAY NIGHT THROUGH SATURDAY NIGHT. ALTHOUGH
THE MID AND UPPER WAVE IS DECENT...HIGH PRESSURE IN SOUTHERN
CANADA IS DRAINING DOWN A DRY...COLD LOW LEVEL FETCH OF AIR
CUTTING OFF A DEEP MOISTURE SUPPLY. IT APPEARS THE ONLY CHANCE FOR
SNOW WILL BE ALONG OUR FAR SOUTHERN ZONES SATURDAY THROUGH SUNDAY.
IF THE ECMWF IS CORRECT... THE CHANCE FOR SNOW WILL BE JUST
FLURRIES FOR OUR SOUTHERN ZONES. SO IN GENERAL...THE WEEKEND LOOKS
TO CONTINUE THE CHILLY WEATHER... WITH SEASONABLY COOL WEATHER
LASTING RIGHT INTO EARLY NEXT WEEK. ELIMINATED ALL MENTION OF POPS
FROM SUNDAY NIGHT ONWARD.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z FRIDAY MORNING) ISSUED AT
700 AM CDT THU MAR 21 2013
VFR WILL CONTINUE THROUGH 22/00Z. A SLOW LOWERING TO CEILINGS 1-3K
FEET AND AREAS OF VISIBILITIES 3-5SM IN SNOW WILL SPREAD INTO THE
AREA FROM THE WEST 22/00Z-12Z...REACHING TO JUST EAST OF HON TO NEAR
FSD TO NEAR SLB BY 22/12Z. VFR WILL CONTINUE NORTHEAST OF THIS LINE.
AFTER 22/06Z LOCAL VISIBILITIES BELOW 3SM IN SNOW WILL DEVELOP
MOSTLY WEST OF THE JAMES RIVER.
&&
.FSD WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
MN...NONE.
IA...NONE.
NE...NONE.
&&
$$
UPDATE...AEB
SHORT TERM...MJF
LONG TERM...MJF
AVIATION...JH
AREA FORECAST DISCUSSION...UPDATED
NWS FORT WORTH TX
709 AM CDT THU MAR 21 2013
.UPDATE...
QUICK UPDATE TO INCLUDE SOME SCATTERED SHOWERS FOR THE MORNING
HOURS ACROSS THE EASTERN HALF OF THE CWA BASED ON RADAR DATA AND
LATEST SOUNDING DATA. SCATTERED SHOWERS HAVE DEVELOPED OVER THE
LAST HOUR FROM NEAR GAINESVILLE TO PALESTINE. SURFACE DEWPOINTS
ARE IN THE 20S IN MANY AREAS BUT THE 12Z FWD SOUNDING INDICATES A
SATURATED LAYER AROUND 750MB AND UNCAPPED ELEVATED CAPE OF ABOUT
200J/KG LIFTING FROM THIS LEVEL. RAP MODEL GUIDANCE INDICATES
STRONG WARM ADVECTION THROUGH THIS LAYER SO WOULD EXPECT THE
SCATTERED CONVECTIVE SHOWERS TO CONTINUE. AT THIS TIME WITH A LACK
OF APPRECIABLE ADDITIONAL FORCING...THINK MOST OF THIS ACTIVITY
WILL REMAIN SHOWERY IN NATURE AND WILL LEAVE OUT A MENTION OF
THUNDER. PRECIP AMOUNTS WILL BE LIGHT AS THE NEAR SURFACE LAYER TO
ABOUT 800MB IS STILL VERY DRY.
DUNN
&&
.AVIATION...
IN ADDITION TO MID-HIGH CLOUDS...A VFR CIG NEAR 060 SHOULD BE IN
PLACE FOR MUCH OF THE DAY. SE WINDS NEAR 10KT THIS MORNING WILL
BECOME S/SE AND INCREASE TO 20KT AND GUSTY BY LATE MORNING. THE
060 VFR CIG WILL GRADUALLY LOWER AFTER SUNSET TO 040 BY 4Z AND TO
MVFR BY 6-7Z TONIGHT.
A SURFACE LOW WILL TRACK VERY NEAR THE METROPLEX LATE TONIGHT SO
WINDS WILL DEFINITELY DIMINISH AFTER 6Z/MIDNIGHT. IT IS UNCLEAR IF
WINDS WILL BACK TO THE EAST OR VEER TO THE WEST AHEAD OF THE
FRONT...BUT FOR NOW HAVE SIDED WITH THE FORECAST SOLUTIONS THAT
INDICATE VEERING WINDS. THE COLD FRONT SHOULD MOVE THROUGH THE
METROPLEX AROUND SUNRISE FRIDAY MORNING WITH NORTH WINDS AT
10-15KT. WITH WESTERLY WINDS ABOVE THE BOUNDARY LAYER AHEAD OF THE
FRONT...THE MVFR CIGS MAY TEMPORARILY CLEAR THE METROPLEX.
CONFIDENCE IN THIS IS LOW AND THUS HAVE LEFT MVFR IN THROUGH THE
NIGHTTIME HOURS FOR NOW. MVFR CIGS WILL PREVAIL BEHIND THE FRONT
FRIDAY MORNING.
FINAL CONCERN IS CONVECTIVE POTENTIAL. BELIEVE BRUNT OF THE
ACTIVITY WILL FIRE NW OF THE METROPLEX AND TRACK GENERALLY WEST TO
EAST. THIS WOULD PUT THE LIKELY TRACK OF THE STORMS JUST TO THE
NORTH OF THE METROPLEX TAF SITES. GIVEN INHERENT UNCERTAINTIES
WITH CONVECTIVE FORECASTS AT THIS SPATIAL SCALE...BELIEVE IT
WOULD BE PRUDENT TO INCLUDE VCTS FOR AFW/DFW/DAL TAF SITES FROM
APPROX 0Z-3Z/7PM-10PM CDT.
TR.92
&&
.PREV DISCUSSION... /ISSUED 410 AM CDT THU MAR 21 2013/
CHANGES ARE ON THE WAY ACROSS NORTH TEXAS THIS MORNING AS SURFACE
PRESSURES BEGIN TO FALL IN RESPONSE TO DEEPENING LEE CYCLONE.
SOUTHERLY WINDS ARE INCREASING WHICH WILL ALLOW FOR A RAPID
INCREASE IN DEWPOINTS OVER THE NEXT SEVERAL HOURS. THICK HIGH
CLOUDS CONTINUE TO STREAM OVERHEAD AND THIS IS LIKELY TO CONTINUE
THROUGH MUCH OF THE DAY. BY LATE THIS AFTERNOON THE SURFACE LOW
WILL BE LOCATED BETWEEN CHILDRESS AND WICHITA FALLS WITH A DRYLINE
EXTENDING FROM THE LOW ACROSS OUR FAR WEST/NORTHWEST COUNTIES.
MODEL GUIDANCE SUGGESTS THAT A WEAK IMPULSE EMBEDDED IN THE FAST
MID/UPPER FLOW WILL CROSS THE RED RIVER VALLEY LATE THIS AFTERNOON
COINCIDING WITH PEAK HEATING AND AN EASTWARD BULGE IN DRYLINE.
WHILE CLOUD COVER IS EXPECTED TO BE AN INHIBITING FACTOR... STRONG
LOW LEVEL WARM ADVECTION FROM MIDDAY THROUGH EARLY EVENING SHOULD
ALLOW SURFACE TEMPS TO WARM INTO THE LOWER 80S ACROSS THE
NORTHWEST THIS AFTERNOON. THIS WARM ADVECTION AND FORCING ALOFT
FROM THE WEAK IMPULSE SHOULD BE SUFFICIENT TO WEAKEN WHAT IS
INITIALLY A STRONG CAP...AND ALLOW CONVECTION TO DEVELOP IN THE
22-00Z TIMEFRAME ACROSS THE NORTHWEST COUNTIES. ALL OF THE HIGH
RESOLUTION CONVECTION ALLOWING GUIDANCE INDICATES THAT THIS WILL
HAPPEN SO HAVE RAISED POPS ACROSS THE NORTHWEST AND RED RIVER
AREAS THROUGH LATE THIS EVENING. FORECAST SOUNDINGS FROM THIS AREA
YIELD ANYWHERE FROM 500-1000J/KG OF MIXED LAYER CAPE AND INDICATE
CONVECTION SHOULD BE SOMEWHAT HIGH BASED WITH LCLS AROUND 800MB.
GIVEN THE DEEP LAYER STRONG WIND FIELDS AND STEEP LAPSE RATES...
DISCRETE SUPERCELL STRUCTURES ARE POSSIBLE POSING MAINLY A LARGE
HAIL AND DAMAGING WIND THREAT. LACK OF MORE IMPRESSIVE SURFACE
BASED INSTABILITY SUGGESTS THAT OVERALL SEVERE WEATHER THREAT IS
ON THE LOW END. SURFACE BASED STORMS SHOULD QUICKLY BECOME
ELEVATED AFTER SUNSET WITH SEVERE THREAT DIMINISHING.
THIS SURFACE LOW WILL MOVE INTO THE ARKLATEX OVERNIGHT INTO FRIDAY
WITH A COLD FRONT SLIDING THROUGH NORTH TEXAS. THE FRONT IS LIKELY
TO BE DRAPED ACROSS THE SOUTHERN COUNTIES DURING THE DAY FRIDAY
WITH NORTHERN AREAS STAYING IN THE 60S AND SOUTHERN AREAS WARMING
INTO THE 80S. WITH THE LACK OF ANY APPRECIABLE FORCING THINK
PRECIP CHANCES WILL BE QUITE LOW ON FRIDAY DESPITE INCREASING
INSTABILITY. FORECAST SOUNDINGS INDICATE MOST AREAS WILL REMAIN
CAPPED.
BY SATURDAY A STRONG S/W WILL DIG INTO THE 4-CORNERS REGION WITH
THE FRONTAL BOUNDARY RETREATING AS A WARM FRONT. THE GUIDANCE
CONTINUES TO STRUGGLE REACHING A CONSENSUS AS TO HOW MUCH OF A
WARM SECTOR RETURNS TO NORTH TEXAS. GFS/CANADIAN RETREAT THE FRONT
THROUGH MOST OF THE AREA WITH NORTH TEXAS MOIST AND UNSTABLE. THE
ECMWF IS SLOWER WITH THE FRONT AND KEEP MOST CONVECTIVE ACTIVITY
ELEVATED ABOVE A SHALLOW COOL LAYER. WITH THE GFS TRENDING IN THE
GENERAL DIRECTION OF THE ECMWF OVER THE LAST 48 HOURS...HAVE SIDED
MORE IN LINE WITH THE ECMWF. CURRENT FORECAST WILL SHOW THE WARM
SECTOR ACROSS THE SOUTHERN HALF OF THE CWA WITH HIGHEST POPS IN
THE MORNING. AS THE S/W MOVES THROUGH THE SOUTHERN PLAINS BY EARLY
EVENING...MORE ROBUST CONVECTION IS LIKELY TO DEVELOP ACROSS THE
EASTERN COUNTIES BEFORE MOVING EAST OUT OF THE AREA. SEVERE
THUNDERSTORMS WILL BE POSSIBLE SATURDAY AFTERNOON/EVENING
PRIMARILY ACROSS THE EASTERN COUNTIES.
AS THIS WHOLE SYSTEM MOVES EAST BY SUNDAY...A STRONG COLD FRONT
MOVES THROUGH THE AREA. SUNDAY INTO THE MIDDLE OF NEXT WEEK LOOKS
QUITE COOL WITH HIGHS IN THE 50S TO MID 60S AND OVERNIGHT LOWS IN
THE 30S. FREEZING TEMPERATURES ARE LIKELY ESPECIALLY IN OUTLYING
AREAS MONDAY MORNING.
DUNN
&&
.PRELIMINARY POINT TEMPS/POPS...
DALLAS-FT. WORTH, TX 74 59 67 50 64 / 20 40 20 20 50
WACO, TX 76 62 78 54 77 / 10 10 10 20 50
PARIS, TX 64 51 62 46 56 / 20 60 20 20 50
DENTON, TX 72 56 62 46 63 / 30 50 20 20 40
MCKINNEY, TX 71 57 62 48 62 / 20 50 20 20 50
DALLAS, TX 75 61 68 51 65 / 20 40 20 20 50
TERRELL, TX 72 60 70 50 65 / 20 30 20 20 50
CORSICANA, TX 74 62 78 55 73 / 20 20 20 20 50
TEMPLE, TX 77 62 81 57 82 / 10 10 10 20 40
MINERAL WELLS, TX 78 54 67 47 69 / 30 30 10 20 30
&&
.FWD WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS DENVER/BOULDER CO
1042 AM MDT THU MAR 21 2013
.UPDATE...
&&
.SHORT TERM...LATEST SATELLITE LOOPS INDICATING MAIN UPPER TROUGH
OVER NORTHERN GREAT BASIN EXTENDING INTO UTAH AND WESTERN COLORADO.
SNOWFALL COVERAGE HAS INCREASED ACROSS THE COLORADO MOUNTAINS...THOUGH
STILL CONFINED MAINLY TO CONTINENTAL DIVIDE AND WESTERN JACKSON
COUNTY. WEB CAMS FROM EISENHOWER TUNNEL INDICATING SNOWFALL HAS
BEEN QUITE VARIABLE IN INTENSITY. WINDS HAVE YET TO INCREASE
ACROSS MOUNTAINS...EXCEPT FOR HIGHER RIDGES. SURFACE DATA SUGGESTING
FRONT IS IN THE VICINITY OF CRAIG IN NORTHWEST COLORADO. SOME
LIGHTNING NOW SHOWING UP IN RIO BLANCO COUNTY...SO SYSTEM IS
RATHER UNSTABLE. ALONG FOOTHILLS AND ACROSS PLAINS...CLOUDS HAVE
INCREASED IN RESPONSE TO INCREASING LIFT. RADAR SHOWING SOME
RETURNS IN NORTHERN WELD COUNTY...BUT APPEARS FROM WEB CAMS THAT
PRECIP IS NOT HITTING THE GROUND. MODELS STILL SHOW TROUGH AND
SURFACE FRONT MOVING ACROSS COLORADO DURING THE DAY WITH PRECIPITATION
SPREADING ACROSS FOOTHILLS AND PLAINS AFTER 18Z. CURRENT FORECASTS
SHOW THIS TREND AND STILL SEEMS REASONABLE. LATEST MODELS CONTINUE
TO INDICATE THE PRECIP CONSOLIDATING INTO A LINE OF SHOWERS EAST
OF DENVER BY MID AFTERNOON. CONFIDENCE HAS INCREASED ENOUGH TO
BOOST POPS TO LIKELY IN THIS AREA AFTER 21Z. REST OF FORECASTS
LOOK ON TRACK. WILL CONTINUE TO MONITOR MOUNTAIN SNOWFALL FOR ANY
HOISTING...STILL THINKING THE HEAVIER SNOWFALL WILL BE OF SHORT
DURATION AND SPOTTY.
.AVIATION...CURRENT TAF TRENDS STILL SEEM ON TRACK. SOUTHEAST
WINDS STILL PERSISTING ACROSS AREA AIRPORTS. SHOULD BEGIN TO SEE
WINDS BECOME MORE SOUTHWEST BY 18Z AHEAD OF SURFACE FRONT. THE
19-20Z TIMING OF THE FRONT ACROSS THE AIRPORTS STILL LOOKING
REASONABLE...BASED ON LATEST RAP AND HRRR...WITH WINDS SHIFTING TO
THE NORTHWEST. SOME SHOWERS POSSIBLE AFTER 19Z AND WILL CONTINUE
WITH THE TEMPO GROUP WITH CEILINGS AROUND 5000 FEET AGL. BEST
CHANCE FOR SHOWERS TO BE EAST OF DENVER. STILL SOME QUESTION
WHETHER THUNDER WILL OCCUR CLOSE ENOUGH TO THE AIRPORTS...WILL
KEEP OUT OF THE TAFS AND CONTINUE TO MONITOR.
&&
.PREV DISCUSSION... /ISSUED 320 AM MDT THU MAR 21 2013/
SHORT TERM...WATER VAPOR IMAGERY SHOWING VIGOROUS UPPER LEVEL
TROF ACROSS THE NORTHERN GREAT BASIN MOVING EAST AND SOUTHEAST
THIS MORNING. QUITE A BIT OF CONVECTIVE ACTIVITY WITH NUMEROUS
LIGHTNING STRIKES ONGOING THRU THE NIGHT ACROSS IDAHO AND UTAH.
THIS ACTIVITY WILL MOVE INTO NORTHERN COLORADO THIS MORNING WITH
AN INITIAL INCREASE IN SNOW SHOWERS OVER THE MOUNTAINS...THEN
PUSHING OUT OVER THE PLAINS THIS AFTERNOON. MAIN CHANGE TO
FORECAST TODAY WAS TO ADD ISOLATED THUNDERSTORMS FOR THE ENTIRE
AREA THIS AFTERNOON. GIVEN THE INSTABILITY UPSTREAM...EXPECT SOME
LIGHTNING STRIKES TO CONTINUE OVER COLORADO. ASSOCIATED COLD FRONT
PUSHING INTO NORTHWEST UTAH EARLY THIS MORNING AND WILL MOVE OVER
THE FRONT RANGE BY EARLY AFTERNOON. GUSTY NORTHWEST WINDS WILL
DEVELOP WHICH WILL INHIBIT SHOWER GENERATION OVER THE ADJACENT
PLAINS BUT LIKELY CONSOLIDATE INTO A LINE OF SHOWERS AND A FEW
THUNDERSTORMS BY MID TO LATE AFTERNOON. EVEN NAM/RUC SHOWING SOME
SURFACED BASED CAPE OF 200-500J/KG. MUST BE SPRING! THERE IS ALSO
SOME UPWARD ASCENT IN THE QG FIELDS ALONG WITH PASSING JET
OVERHEAD. GIVEN THE ABOVE HAVE ALSO INCREASED POPS 10-15 PERCENT
OVER THE PLAINS. MAY NEED A FURTHER INCREASE OVER THE PLAINS
PENDING ON THE DEVELOPMENT OF CONVECTION AS IT PLAYS OUT THIS
AFTERNOON.
AS FOR THE MOUNTAINS...EXPECT AN INCREASE IN SNOWFALL THIS MORNING
WITH THE APPROACH OF UPPER TROF AND SNOW MAY BECOME HEAVY FOR
SHORT DURATIONS WITH THE CONVECTION. WILL OPT NOT TO GO THE
ADVISORY ROUTE AS THE HEAVIER SNOWFALL WILL BE OF SHORTER DURATION
AND AREAL COVERAGE MORE SPOTTY. PRECIP AND CLEARING WILL COMMENCE
RAPIDLY LATE AFTERNOON AND EVENING FROM WEST TO EAST WITH THE
FAST MOVING SYSTEM. WITH THE CLEARING SKIES...OVERNIGHT LOWS WILL
BE COLDER. EXPECT SOME LINGERING SNOW SHOWERS IN THE MOUNTAINS
GIVEN SHALLOW MOISTURE AND CONTINUED OROGRAPHICS.
LONG TERM...UPPER TROUGH OVER THE NORTHERN ROCKIES WILL BE MOVING
SOUTHEAST FRIDAY WITH MOISTURE AND LIFT INCREASING OVER THE
FORECAST AREA. FLOW ALOFT WILL BEGIN OUT OF THE SOUTHWEST...BUT
THEN DEPENDING ON THE TRACK OF THE SYSTEM...THE 700 MB LOW WILL
AFFECT WHERE AND HOW MUCH PRECIPITATION OCCURS. WITH QUITE COLD
TEMPERATURES ASSOCIATED WITH THIS SYSTEM...HAVE FOLLOWED THE GFS
AND ECMWF POSITIONS WHICH ARE FURTHER SOUTH THAN THE NAM SOLUTION.
THIS WOULD BRING UPSLOPE FLOW SOONER AND FOR LONGER TO THE FRONT
RANGE COMPARED TO THE NAM SOLUTION. HAVE KEPT THE CHANCE OF SNOW
SHOWERS OVER THE MOUNTAINS AND RAIN SHOWERS OVER THE PLAINS BEFORE
THE COLD FRONT SINKS SOUTH FRIDAY NIGHT. HAVE INCREASED POPS
SLIGHTLY FOR FRIDAY NIGHT INTO SATURDAY TO ACCOUNT FOR THE UPSLOPE
STARTING FRIDAY NIGHT. HOWEVER...AM NOT CONFIDENT IN THE AMOUNT OF
WATER AND SNOW THE MODELS ARE PRODUCING. IT ALL SEEMS TO WET
COMPARED TO THE PRECIPITABLE WATER AMOUNTS BEING GENERATED. HAVE
STAYED ON THE LOWER SIDE OF QPF AND SNOW AMOUNTS AND AM NOT
CONFIDENT IN ISSUING ANY HIGHLIGHTS AT THIS POINT. CURRENTLY WILL
BE EXPECTING 3 TO 6 INCHES FRIDAY NIGHT INTO SATURDAY AFTERNOON
FOR THE PLAINS AND 6 TO 11 INCHES FOR THE FRONT RANGE MOUNTAINS
AND UPPER FOOTHILLS. NORTH WINDS WILL BE PICKING UP OVER THE
PLAINS FRIDAY NIGHT AND INTO SATURDAY BEHIND THE COLD FRONT TO
LIKELY PRODUCE AREAS OF BLOWING SNOW OVER THE EASTERN PLAINS.
AFTER LOWS IN THE LOW 20S OVER THE PLAINS AND IN THE LOW TEENS IN
THE MOUNTAINS FRIDAY NIGHT...TEMPERATURES SATURDAY WILL STRUGGLE
TO WARM MUCH ABOVE THOSE READINGS.
SNOW WILL LIKELY TAPER OFF SATURDAY NIGHT INTO SUNDAY MORNING WITH
CLEARING SKIES ALLOWING FOR MUCH COLDER THAN NORMAL TEMPERATURES
SATURDAY NIGHT. ANOTHER SYSTEM CLOSE ON THE DEPARTING SYSTEMS
HEELS WILL KEEP A CHANCE OF SNOW FOR THE AREA SUNDAY AND MONDAY
WITH CONTINUED COLD TEMPERATURES. WEAK RIDGING FOLLOWING BEHIND
THESE TWO SYSTEMS SHOULD BRING SLIGHTLY WARMER AND DRIER WEATHER
TUESDAY AND WEDNESDAY WITH TEMPERATURES STILL BELOW NORMAL FOR
THIS TIME OF EARLY SPRING.
AVIATION...DRAINAGE WINDS EARLY THIS MORNING WILL SHIFT AROUND
TO THE WEST AND NORTHWEST THIS AFTERNOON AS SURFACE FRONT MOVES
THROUGH BETWEEN 19-20Z. EXPECT SOME GUSTS IN THE 20-30 MPH
RANGE...ESPECIALLY AT BJC AND DEN. BIGGEST QUESTION WILL BE ON
CONVECTION AT THE AIRPORTS AND THIS WILL BE CLOSE CALL AS THE
DOWNSLOPE WINDS WILL BE FIGHTING THE AVAILABLE MOISTURE. MAY OPT
TO ADD A TEMPO GROUP GIVEN THE IMPRESSIVE SHOWERS/STORMS UPSTREAM.
&&
.BOU WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...D-L
LONG TERM....KRIEDERMAN
AVIATION...D-L
AREA FORECAST DISCUSSION
NWS TOPEKA KS
1233 PM CDT THU MAR 21 2013
...UPDATE TO AVIATION...
.DISCUSSION...
RADAR HAS SHOWN A PERSISTENT BAND OF RETURNS ACROSS NORTHEAST KS.
THE LAST COUPLE OBS FORM KLWC AND A FEW PUBLIC REPORTS INDICATE
THERE IS NOT MUCH PRECIP FALLING FROM THIS BAND ON RADAR. THINK THIS
MAY BE DUE TO MORE DRY AIR IN THE BOUNDARY LAYER THAN EXPECTED AS
DEWPOINT TEMPS HAVE STRUGGLED TO WARM INTO THE MID AND UPPER TEENS
WHILE THE FORECAST WAS EXPECTING DEWPOINTS AROUND 20 BY NOW. ALSO
FORCING FOR PRECIP APPEARS TO BE COMPLETELY MESOSCALE DRIVEN WITH A
BAND OF FRONTOGENESIS COLLOCATED WHERE THE RADAR SHOWS THE
REFLECTIVITY. THIS BAND OF FRONTOGENESIS IS PROGGED TO SLOWLY MOVE
EAST WHILE A SHORTWAVE RIDGE AXIS BUILD UP JUST TO THE WEST OF THE
FORECAST AREA. IN GENERAL THE 12Z NAM AND RAP ARE POINTING TO A
LIGHT QPF EVENT IF ANYTHING FALLS WITH ONLY MARGINAL FORCING AT
BEST. THEREFORE WILL TREND POPS DOWN FOR TODAY WITH SOME LIKELY POPS
STILL IN THE FAR EASTERN COUNTIES. SNOW ACCUMULATIONS ARE EXPECTED
TO BE LESS THAN AN INCH GIVEN SOIL TEMPS AROUND 40 DEGREES AND KDOT
REPORTING ROAD TEMPS GENERALLY ABOVE FREEZING.
WOLTERS
&&
.AVIATION...
KTOP IS IMPROVING BACK TO VFR AT 18Z AS A BAND OF LIGHT SNOW SHIFTS
EAST OF TERMINAL. KFOE AND KMHK SITES SHOULD REMAIN IN VFR THROUGH 00Z.
THERE IS AN OUTSIDE CHANCE OF LIGHT RAIN OR SNOW THROUGH THE
AFTERNOON AND EARLY EVENING BUT CONFIDENCE OF A PRECIPITATION BAND
IMPACTING SITES WAS TOO LOW TO INCLUDE. HIGHEST CONFIDENCE IN
LIGHT SNOW OR DRIZZLE DEVELOPING IS MAINLY AFT 06Z AT TERMINALS AS
NEXT WAVE PASSES THRU. IF HEAVIER PRECIPITATION BAND DEVELOPS...CIGS
MAY BRIEFLY FALL TO IFR OTHERWISE REMAIN MVFR THROUGH 18Z.
EASTERLY WINDS AOA 10 KTS WILL WANE AOB 10 KTS AFT 00Z FRIDAY WITH
DIRECTION GRADUALLY BACKING TOWARDS THE EAST NORTHEAST BLO 10 KTS
AFT 06Z.
BOWEN
&&
.TOP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS GRAND RAPIDS MI
203 PM EDT THU MAR 21 2013
.SYNOPSIS...
ISSUED AT 334 AM EDT THU MAR 21 2013
THE REGION WILL CONTINUE TO SEE SNOW SHOWERS TODAY...HOWEVER THEY
SHOULD GRADUALLY BECOME MORE SCATTERED. ANY ADDITIONAL ACCUMULATION
SHOULD REMAIN AN INCH OR LESS IN MOST PLACES. THE SNOW WILL COME TO
AN END...OR DIMINISH TO FLURRIES LATE TONIGHT. HIGHS TODAY WILL BE
IN THE UPPER 20S TO AROUND 30.
FRIDAY AND SATURDAY WILL SEE QUIET WEATHER WITH A SLIGHT WARMING
TREND WITH HIGHS GETTING INTO THE 30S EACH DAY.
THERE WILL BE THE CHANCE OF RAIN OR SNOW RETURNING MONDAY AND
TUESDAY OF NEXT WEEK.
&&
.UPDATE...
ISSUED AT 720 AM EDT THU MAR 21 2013
THE WEATHER WINTER WEATHER ADVISORY HAS BEEN CANCELED SINCE ANY
REMAINING SNOWFALL IS LIGHT AND THAT IS DIMINISHING.
UPDATE ISSUED AT 647 AM EDT THU MAR 21 2013
LOOKING AT THE LATEST RADAR LOOPS... THE HRRR MODEL OUTPUT... THE
LATEST NAM DATA (LIFT IN THE DGZ MOSTLY) IT WOULD SEEM THE THREAT
FOR SIGNIFICANT SNOW SHOWERS HAS ENDED SO I WILL DROP THE WINTER
WEATHER ADVISORY ONCE I SEND THIS MESSAGE.
&&
.SHORT TERM...(TODAY THROUGH SATURDAY)
ISSUED AT 334 AM EDT THU MAR 21 2013
WILL BUMP THE END TIME OF THE ADVISORY TO 14Z TO COVER IMPACTS
THROUGH THE MORNING COMMUTE. LAKE EFFECT SNOW SHOWERS CONTINUE...
BUT A DOMINATE BAND DID NOT DEVELOP...KEEPING ACCUMS FROM GETTING
TOO HIGH. EXPECT LAKE SHORE AREAS WILL SEE AN ADDITIONAL INCH OR
TWO THIS MORNING. INVERSION HEIGHTS AND DELTA T/S GRADUALLY BECOME
LESS FAVORABLE FOR INTENSE SNOW SHOWERS THROUGH THE DAY AND A
DOWNWARD TREND SHOULD BE SEEN BY LATE MORNING INTO THE AFTERNOON.
A SURFACE TROUGH WAS SAGGING SOUTH OVER NORTHERN LOWER THIS
MORNING. THIS ALONG WITH DAYTIME HEATING WILL SPARK SCATTERED SNOW
SHOWERS INLAND TOO. SO WILL MAIN POPS INLAND...BUT ANY ACCUMS WILL
BE UNDER AN INCH.
THE DOWNWARD TREND IN THE SNOW ACTIVITY WILL CONTINUE INTO TONIGHT
AND SHOULD LARGELY BE JUST FLURRIES BY 06Z.
WEAK SURFACE AND UPPER RIDGING BUILDS FOR THE END OF THE WEEK.
TRENDED A BIT MORE CLOUDY FOR FRIDAY AND SATURDAY. IT APPEARS A
FAIR AMOUNT OF LOW LEVEL MOISTURE LINGERS UNDER A TEMP INVERSION.
HOWEVER GIVEN THE HIGHER SUN ANGLE AND BETTER MIXING THIS TIME OF
YEAR WOULD EXPECT TO SEE AT LEAST SOME SUN EACH DAY. LOW TO MID
30S FRI SHOULD WARM TO THE UPPER 30S TO AROUND 40 BY SATURDAY.
.LONG TERM...(SATURDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 334 AM EDT THU MAR 21 2013
WE CONTINUE TO WATCH THE SYSTEM THAT NOW LOOKS LIKE IT WILL FOR THE
MOST PART PASS SOUTH OF THE GRR CWA SUN INTO TUESDAY. OTHERWISE
COLDER THAN NORMAL TEMPERATURES WILL CONTINUE THROUGH MOST OF THIS
COMING WEEK.
THE HIGH LATITUDE BLOCKING IS FORECAST TO CONTINUES INDEFINITELY.
THIS KEEPS THE POLAR JET CORE WELL SOUTH OF MICHIGAN THROUGH NEXT
WEEK. WHICH IS WHAT KEEPS THE WARMER AIR WELL SOUTH OF MICHIGAN
TOO.
THE STORM WE ARE WATCHING COMES FROM A PACIFIC SYSTEM THAT MOVED ON
SHORE TODAY NEAR VANCOUVER BRITISH COLUMBIA. THE UPPER LEVEL ENERGY
FRAGMENTS AS THE SYSTEM MOVES THROUGH THE ROCKY MOUNTAINS THIS
WEEKEND. SO WHILE A CLOSED UPPER LOW DOES MOVE EAST OVER THE OHIO
VALLEY IN THE MONDAY TIME FRAME...TAKING THE BULK OF THE
PRECIPITATION SOUTH OF MICHIGAN WITH IT... A CONSIDERABLE AMOUNT OF
UPPER TROUGHING REMAINS WEST OF THE GREAT LAKES. SO... EVEN IF THE
STORM PRECIPITATION ITSELF MISSES SOUTHWEST LOWER MICHIGAN THE UPPER
LEVEL SYSTEM WILL STILL HAVE TO MOVE THROUGH THE AREA IN THE MON-WED
TIME FRAME. THERE IS MID LEVEL MOISTURE WITH THE UPPER LEVEL FEATURE
SO THAT WILL LEAD TO INSTABILITY SNOW SHOWERS MONDAY INTO WEDNESDAY.
ANOTHER ISSUE TOO IS SOMETIMES WHEN THERE IS SO MUCH UPPER TROUGHING
HANGING BACK...WEST OF THE GREAT LAKES THE SURFACE STORM ENDS UP
WAITING OF THE UPPER LEVEL ENERGY TO WEST TO REACH IT BEFORE MOVING
OUT... SO I AM STILL NOT TOTALLY ON BOARD WITH THIS SYSTEM STAYING
SOUTH. EVEN SO WE HAVE LOW CHANCE POPS SUN THROUGH WEDNESDAY.
IF THIS WORKS OUT AS THE CURRENT MODELS SUGGEST EXPECT PARTLY TO
MOSTLY CLOUDY SKIES... FLURRIES FROM TIME TO TIME AND TEMPERATURES
IN THE 20S AT NIGHT AND 30S DURING THE DAY (FOR THE MOST PART).
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z FRIDAY AFTERNOON)
ISSUED AT 203 PM EDT THU MAR 21 2013
LAKE EFFECT SNOW SHOWERS ARE ONGOING ACROSS THE AREA ONCE AGAIN
THIS AFTERNOON...HOWEVER THEY ARE A FAIR AMOUNT LESS INTENSE THAN
THE LAST COUPLE OF DAYS. THIS IS LEADING TO MOSTLY MVFR CONDITIONS
WITH SOME SCATTERED IFR UNDER THE BEST BANDS FROM KMKG TO KAZO. WE
EXPECT THE SPOTTY IFR WILL CONTINUE FOR THE NEXT 2-4 HOURS BEFORE
THE LATEST WAVE MOVES SOUTH OF THE AREA AND SNOW SHOWERS DIMINISH.
WINDS WILL ALSO DIMINISH TOWARD 23Z OR SO WITH SUNSET.
LIGHT SNOW SHOWERS/FLURRIES WILL CONTINUE THROUGH THE NIGHT. MVFR
TO VFR CONDITIONS ARE EXPECTED. SNOW SHOWERS WILL THEN END ON FRI
MORNING AS TEMPERATURES MODERATE AND THE CLOUD LAYER IS UNABLE TO
MAKE SNOW FLAKES. WE EXPECT THERE IS A GOOD CHANCE CIGS SHOULD
BECOME VFR EVERYWHERE ON FRI AFTERNOON.
&&
.MARINE...
ISSUED AT 334 AM EDT THU MAR 21 2013
WILL MAINTAIN SCA FOR BRISK NW WINDS INTO TONIGHT.
&&
.HYDROLOGY...
ISSUED AT 334 AM EDT THU MAR 21 2013
NO ISSUES EXPECTED.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LM...SMALL CRAFT ADVISORY UNTIL 1 AM EDT FRIDAY FOR LMZ844>849.
&&
$$
UPDATE...WDM
SYNOPSIS...JK
SHORT TERM...JK
LONG TERM...WDM
AVIATION...NJJ
HYDROLOGY...JK
MARINE...JK
AREA FORECAST DISCUSSION
NWS DULUTH MN
308 PM CDT THU MAR 21 2013
.SHORT TERM.../NOW - FRIDAY/
AT 3PM/2000Z...THERE WAS A RIDGE OF HIGH PRESSURE OVER THE
NORTHERN PLAINS AND SOUTHERN MINNESOTA. THE NORTHLAND HAD LIGHT NW
WINDS DUE TO A LARGE LOW PRESSURE SYSTEM OVER THE NORTHEASTERN
UNITED STATES AND SOUTHEASTERN CANADA. MOST OF THE NORTHLAND HAD
SUNNY TO MOSTLY SUNNY SKIES...BUT THERE WAS STILL SOME LINGERING
LAKE EFFECT SNOW RELATED OVC CLOUDS OVER THE FAR EASTERN FORECAST
AREA IN NW WISCONSIN. THE OVC CLOUDS WERE QUICKLY DIMINISHING AS
THE WINDS WEAKENED OVER WESTERN LAKE SUPERIOR...CUTTING OFF THE
MOISTURE SUPPLY. TEMPERATURES WERE IN THE LOWER TO UPPER 20S
ACROSS THE NORTHLAND.
TONIGHT...THE HIGH PRESSURE IN THE NORTHERN PLAINS WILL SLOWLY
MOVE INTO THE NORTHLAND. THE NORTHLAND CAN EXPECT CLEAR TO MOSTLY
CLEAR SKIES. THERE COULD BE SOME CLOUDS OVER THE TIP OF THE
ARROWHEAD LATE TONIGHT. THE NAM AND RAP INDICATE SOME ENHANCED LOW
LEVEL MOISTURE MOVING INTO THAT AREA...BUT LEANED ON A CLEAR
FORECAST. THE MODEL GUIDANCE IS LIKELY MUCH TOO WARM CONSIDERING
THE CLEAR SKIES AND VERY LIGHT WINDS EXPECTED FOR TONIGHT...SO
UNDERCUT THE MODEL CONSENSUS BY SEVERAL DEGREES. OVERNIGHT LOWS
WILL PROBABLY BE WELL INTO THE SINGLE DIGITS BELOW ZERO ACROSS
MOST OF THE NORTHLAND.
FRIDAY...THE HIGH PRESSURE OVER THE NORTHLAND WILL PROMOTE SUNNY
TO MOSTLY SUNNY SKIES FOR AT LEAST THE MORNING. THERE COULD BE
SOME INCREASING CLOUD COVER IN THE AFTERNOON BASED ON MODEL RH.
HOWEVER...LEANED ON LESS CLOUD COVER SINCE THE MODELS SEEM TO BE
EXAGGERATING THE POTENTIAL FOR CLOUD COVER. FRIDAY COULD VERY
EASILY BE SUNNY ACROSS THE REGION...SO UPDATES MIGHT NEED TO BE
MADE IN THE FUTURE. HIGH TEMPERATURES WILL LIKELY BE IN THE LOWER
30S.
.LONG TERM.../FRIDAY NIGHT - WEDNESDAY NIGHT/
CONTINUED QUIET WEATHER CONDITIONS THROUGH THE WEEKEND AND INTO
THE MIDDLE OF NEXT WEEK WITH A NARROW RIDGE OF HIGH PRESSURE
SITUATED OVER THE UPPER MIDWEST BETWEEN TWO SLOW MOVING UPPER
LOWS. THE LOW TO THE WEST WILL EVENTUALLY UNDERCUT THE HIGH
PRESSURE BY THIS WEEKEND. HOWEVER...THE ACTIVE PATTERN WILL REMAIN
WELL TO THE SOUTH AND LEAVE THE NORTHLAND MOSTLY DEVOID OF
PRECIPITATION. THE LOW LEVEL FLOW WILL BE FAVORABLE FOR A
PERSISTENT E/NE WIND OFF LAKE SUPERIOR AND KEEP MUCH OF THE
NORTHLAND UNDER THE INFLUENCE OF MOSTLY CLOUDY SKIES THROUGH THE
WEEK. THE LACK OF SUN...COMBINED WITH A RELATIVELY COLD AIR
MASS...850MB TEMPS -11 DEG C...WILL KEEP AFTERNOON HIGHS IN THE
LOWER 30S AND OVERNIGHT LOWS IN THE TEENS. ROUGHLY 5-10 DEG BELOW
AVERAGE. COULD SEE A FEW WEAK WAVES ROTATE WWD FROM THE UPPER
TROUGH OVER ERN CANADA EARLY NEXT WEEK...BUT ONLY A SLIGHT CHANCE
OF LIGHT SNOW IS POSSIBLE FROM THESE...WITH LITTLE TO NO SNOW
ACCUMULATING.
&&
.AVIATION.../18Z TAF ISSUANCE/
VFR CONDITIONS TODAY WITH A CHANCE OF A LOW/MID LEVEL STRATO-CU
SCT DECK FORMING AFTER 21Z. FAIRLY DRY AIR IN PLACE UNDER HIGH
PRESSURE SO...ANY CLOUDS THAT DO TRY TO FORM TODAY WILL NOT BECOME
THICK ENOUGH FOR BKN CIGS TO FORM. WINDS WILL REMAIN LIGHT AND
FROM THE NORTH. AS HIGH PRESSURE SETTLES IN TONIGHT AND WINDS
BECOME CALM...THE POTENTIAL FOR FOG RETURNS. HAVE INCREASED AMT
AND DURATION OF FOG WITH LOW-END IFR OR LIFR VSBYS POSSIBLE.
&&
.POINT TEMPS/POPS...
DLH -1 30 12 32 / 0 0 10 10
INL -7 29 9 31 / 0 0 10 10
BRD -3 31 12 33 / 0 0 0 10
HYR -5 34 8 34 / 0 0 0 10
ASX 2 32 11 32 / 0 0 0 0
&&
.DLH WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
&&
$$
SHORT TERM...GROCHOCINSKI
LONG TERM....TENTINGER
AVIATION...TENTINGER
AREA FORECAST DISCUSSION...UPDATED
NWS DULUTH MN
1226 PM CDT THU MAR 21 2013
.AVIATION...18Z TAF ISSUANCE...
VFR CONDITIONS TODAY WITH A CHANCE OF A LOW/MID LEVEL STRATO-CU
SCT DECK FORMING AFTER 21Z. FAIRLY DRY AIR IN PLACE UNDER HIGH
PRESSURE SO...ANY CLOUDS THAT DO TRY TO FORM TODAY WILL NOT BECOME
THICK ENOUGH FOR BKN CIGS TO FORM. WINDS WILL REMAIN LIGHT AND
FROM THE NORTH. AS HIGH PRESSURE SETTLES IN TONIGHT AND WINDS
BECOME CALM...THE POTENTIAL FOR FOG RETURNS. HAVE INCREASED AMT
AND DURATION OF FOG WITH LOW-END IFR OR LIFR VSBYS POSSIBLE.
&&
.PREV DISCUSSION... /ISSUED 950 AM CDT THU MAR 21 2013/
UPDATE...
THE FORECAST WAS UPDATED THROUGH THIS EVENING. THE CHANGES WERE
MOSTLY MINOR...BUT MADE SOME CHANGES TO CLOUD COVER BASED ON THE
LATEST TRENDS. THE PREVIOUS FORECAST WAS CALLING FOR A LOT OF
DEVELOPING CLOUD COVER ACROSS THE WESTERN FORECAST AREA SIMILAR TO
WHAT THE ARROWHEAD AND NW WISCONSIN CURRENTLY HAVE. HOWEVER...THE
MODELS WERE CALLING FOR THAT YESTERDAY TOO...BUT THE CLOUDS MOSTLY
REMAINED IN THE ARROWHEAD AND NW WISCONSIN. THEREFORE...CHANGED
THE FORECAST TO REFLECT MY SKEPTICISM...BUT DID FORECAST MOSTLY TO
PARTLY SUNNY SKIES ACROSS THE WESTERN FORECAST AREA IN CASE
CLOUDS DO DEVELOP. FOR THIS MORNING AND EARLY THIS AFTERNOON...MADE
SURE WE HAD SCATTERED FLURRIES IN THE FORECAST FOR MOST OF THE
AREAS THAT CURRENTLY HAVE BKN/OVC CLOUD COVER. THE HIGH
TEMPERATURE FORECAST MOSTLY LOOKED GOOD...BUT LOWERED THE
TEMPERATURES ACROSS THE ARROWHEAD A BIT DUE TO THE CLOUD COVER.
PREV DISCUSSION... /ISSUED 648 AM CDT THU MAR 21 2013/
AVIATION...12Z TAF ISSUANCE.
A SHORT WAVE WILL SPREAD A STRATUS DECK SOUTH AND EAST OVER MUCH
OF THE FORECAST AREA TODAY. PREVAILING MVFR CIGS OF 2-3 KFT WILL
BE FOUND IN THE EASTERN TERMINALS...INCLUDING KHIB/KHYR.
TERMINALS FURTHER WEST...INCLUDING KINL/KBRD CAN EXPECT VFR
CONDITIONS WITH PERIODS OF MVFR CIGS. GENERALLY CLR SKIES AND VFR
CIGS WILL PREVAIL OVERNIGHT...WITH AREAS OF RESTRICTED VSBYS OF
3-5 SM DUE TO POSSIBLE LIGHT FG/BR AFTER 06Z.
PREV DISCUSSION... /ISSUED 329 AM CDT THU MAR 21 2013/
SHORT TERM...THROUGH FRIDAY.
A SHORTWAVE...WHICH IS AN EXTENSION OF THE LARGE EASTERN
CONUS/EASTERN CANADIAN UPPER TROUGH...WAS MOVING THROUGH THE
NORTHLAND AND SHOULD MOVE SOUTH AND EAST TODAY.
THERE CONTINUED TO BE SOME FLURRIES FALLING OUT OF A DECK OF CLOUDS
THAT COVERED PORTIONS OF NORTHEAST MINNESOTA AND NORTHERN
WISCONSIN...AND SOME LAKE EFFECT SNOW SHOWERS CONTINUED ALONG THE
SOUTH SHORE. CONDITIONS BECOME LESS FAVORABLE FOR LES TODAY...AS
850MB TEMPERATURES WARM THROUGH THE MORNING WITH DRIER AIR MOVING
OVER LAKE SUPERIOR. WE DON`T EXPECT MUCH ACCUMULATION THIS MORNING
OVER THE SNOWBELT REGION. CLOUD COVER WILL BE A CHALLENGE TODAY. THE
WESTERN EDGE OF THE CLOUDS THIS MORNING WAS MOVING SLOWLY EAST AND
THE CLOUDS APPEAR TO BE DIMINISHING. HOWEVER...THE RAP SUGGESTS
WE`LL SEE SOME REDEVELOPMENT BY LATE MORNING/EARLY AFTERNOON WITH
SOME HEATING. WE DID FOLLOW THAT TREND...AND HAVE PARTLY TO MOSTLY
CLOUDY SKIES GOING FOR ABOUT THE SOUTHERN HALF TO TWO THIRDS OF THE
CWA THROUGH MID AFTERNOON. WE EXPECT HIGHS TODAY TO BE MAINLY IN THE
MID TWENTIES...BUT WILL HAVE TO ADJUST A FEW DEGREES DEPENDING ON
THE EXTENT OF THE CLOUD COVER.
TONIGHT INTO FRIDAY THE NORTHLAND GETS SQUEEZED BETWEEN TWO
TROUGHS...ONE EXTENDING FROM NORTHERN BRITISH COLUMBIA INTO THE
NORTHERN PLAINS...AND THE PERSISTENT EASTERN TROUGH. WE EXPECT
TONIGHT TO BE CLEAR TO PARTLY CLOUDY FOR MOST AREAS WITH LIGHTER
WINDS. WE WENT BELOW MOST OF THE LOW TEMP GUIDANCE TONIGHT...CLOSER
TO THE NHGEMBC. DEEP SNOWPACK...LIGHT WINDS AND MINIMAL CLOUD COVER
SHOULD ALLOW FOR THE COLD TEMPS. THICKER CLOUDS WILL MOVE INTO THE
ARROWHEAD/BORDER REGION LATER TONIGHT...AND THAT WILL KEEP THEM FROM
REALLY GETTING COLD.
FRIDAY WILL BE PARTLY SUNNY WITH HIGHS A BIT WARMER...FROM 28 TO 34
FOR MOST AREAS.
LONG TERM...FRIDAY NIGHT THROUGH THURSDAY.
THE WESTERN LAKE SUPERIOR REGION WILL SITUATED BETWEEN A LARGE CUT
OFF LOW ROTATING OVER THE NEW ENGLAND STATES...AND A DIGGING TROUGH
OVER THE ROCKIES THROUGH THE WEEKEND. THIS WILL RESULT IN WEAK SFC
RIDGING OVER THE CWA FRIDAY NIGHT/SAT. A NORTH TO NORTHEAST FLOW
WILL DEVELOP SAT NIGHT THROUGH SUNDAY AS A VORT MAX WITH SFC
REFLECTION LOW EJECTS OUT OF THE BASE OF THE TROUGH AND TRACKS EAST
ACROSS THE SRN PLAINS. AT THIS TIME...MODELS IN AGREEMENT THAT THE
NRN EXTENT OF ANY PRECIPITATION ASSOCIATED WITH THE WAVE TRANSLATES
ALONG THE SOUTHERN MN/WI STATE LINES. MEANWHILE...AN ELONGATED VORT
MAX BREAKS FREE FROM THE EASTERN LOW...AND RETROGRADES ACROSS
ONTARIO FRIDAY NIGHT...DROPPING INTO THE NRN LAKE SUPERIOR/MN
ARROWHEAD REGION SATURDAY. ATTM...THIS VORT IS EXPECTED TO BRING
PRIMARILY INCREASING CLOUDS. HOWEVER...RH FIELDS AND LATEST NAM BUFR
SOUNDINGS SHOWS INCREASING LOW LEVEL MOISTURE FRI NIGHT THAT
SUGGESTS A SMALL POTENTIAL FOR SOME FOG/BR OR POSSIBLY VERY LIGHT
DZ/SN SAT/SAT NIGHT. HOWEVER...HAVE KEPT FCST DRY THROUGH THE
WEEKEND AS ANY THE PRECIP CHCS ARE VERY SMALL AND QPF WILL BE
ISOLATED AND LIGHT.
BEYOND THE WEEKEND...THE H50 FLOW BECOMES VERY DISORGANIZED AS
MODELS TRY TO RESOLVE PHASING THE DOUBLE LOWS OVER THE ERN COAST.
GENIALLY HAVE KEPT EXTENDED DRY WITH TEMPERATURES NEAR TO A FEW
DEGREES BELOW NORMAL.
&&
.POINT TEMPS/POPS...
DLH -1 31 13 31 / 0 10 10 10
INL -8 30 9 32 / 0 10 10 10
BRD -2 32 15 32 / 0 10 10 10
HYR -5 33 11 34 / 0 10 10 10
ASX 3 31 13 32 / 10 10 10 10
&&
.DLH WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
&&
$$
AVIATION...TENTINGER
AREA FORECAST DISCUSSION
NWS HASTINGS NE
105 PM CDT THU MAR 21 2013
.SHORT TERM...(TODAY THROUGH TONIGHT)
ISSUED AT 510 AM CDT THU MAR 21 2013
ALTHOUGH THESE NEXT 24 HOURS DO NOT APPEAR TO PACK THE PUNCH THAT
THE WEEKEND WILL...THERE ARE NONETHELESS TWO DISTURBANCES THAT
WILL MAKE THE IMMEDIATE SHORT TERM QUITE TRICKY...AS THE
FIRST ONE COULD BRING A LIGHT DUSTING OF SNOW/POSSIBLY A BRIEF
SHOT OF SLEET TO PARTS OF THE CWA THIS MORNING...AND THEN A
SOMEWHAT MORE POTENT WAVE TONIGHT COULD BRING ROUGHLY 1 INCH OF
SNOW TO MUCH OF THE CWA...ALONG WITH MAYBE SOME LIGHT FREEZING
DRIZZLE IN ITS WAKE. ALTHOUGH ITS CERTAINLY NOT COMPLETELY OUT OF
THE QUESTION THAT TONIGHT/S EVENT MIGHT CREATE SOME SLICK ROADS
FOR THE FRIDAY MORNING COMMUTE...THE GENERALLY MINOR EXPECTED SNOW
AMOUNTS AND LACK OF CONFIDENCE IN FREEZING DRIZZLE HAVING MUCH
IMPACT PRECLUDES ANY TYPE OF FORMAL WINTER WEATHER ADVISORY AT THIS
TIME...ALTHOUGH WILL CONTINUE TO SUGGEST THE POSSIBILITY OF MINOR
IMPACTS IN THE HAZARDOUS WEATHER OUTLOOK.
09Z OBJECTIVE SURFACE ANALYSIS DEPICTS A BROAD RIDGE AXIS CENTERED
FROM THE EASTERN DAKOTAS THROUGH MO/AR...WHILE TO THE WEST A
MODEST NORTH-SOUTH HIGH PLAINS LEE TROUGH IS IN PLACE. IN BETWEEN
THESE FEATURES...FAIRLY STEADY EAST-SOUTHEAST BREEZES OF 10-20 MPH
WITH SOME HIGHER GUSTS HAVE RAMPED UP ACROSS THE CWA. PRE-DAWN
TEMPERATURES ARE NEAR TO SLIGHTLY HIGHER THAN EARLIER
FORECAST...BUT WILL STILL AIM FOR OVERNIGHT LOWS RANGING FROM LOW-
MID 20S CENTRAL/NORTHEAST TO UPPER 20S/NEAR 30 SOUTHWEST.
ALOFT...WATER VAPOR IMAGERY AND SHORT TERM MODEL DATA DEPICT
PROGRESSIVE WEST-NORTHWEST FLOW ALOFT OVER THE CENTRAL
PLAINS...IN BETWEEN A DEEP LOW OVER THE NORTHEAST CONUS...AND AN
UPSTREAM MID LEVEL SHORTWAVE TROUGH STEADILY APPROACHING THE
REGION FROM THE NORTHERN ROCKIES. ALTHOUGH THE LOCAL AREA IS
TECHNICALLY UNDER A FAIRLY SMALL SCALE AND BROAD SHORTWAVE RIDGE
ALOFT AT THIS TIME...PRONOUNCED ISENTROPIC LIFT EVIDENT ON THE
295K SURFACE WITHIN THE ENTRANCE REGION OF A DEPARTING UPPER LEVEL
JET STREAK IS PROMOTING A STEADILY ORGANIZING NORTHWEST-SOUTHEAST
BAND OF PRECIPITATION ACROSS MAINLY THE NORTHEAST 1/2 OF THE CWA.
SO FAR...THERE HAS BEEN FAIRLY LIMITED GROUND TRUTH OF THIS
PRECIPITATION REACHING THE GROUND...ALTHOUGH A HANDFUL OF
AUTOMATED SENSORS INCLUDING ORD/BROKEN BOW ARE NOW REPORTING LIGHT
SNOW.
FORECAST WISE TODAY...HAVE BROKEN POPS/WEATHER INTO 3-HOUR BLOCKS
THROUGH THE REST OF THIS MORNING...WITH THE HIGHEST 30-50 PERCENT
CHANCES FOR LIGHT MEASURABLE SNOW AND POSSIBLY A BRIEF BIT OF
SLEET FOCUSED NORTHEAST OF A LINE FROM KEARNEY TO SUPERIOR...WHICH
LINES UP QUITE NICELY WITH THE SATURATED 295K SURFACE PER THE 06Z
NAM. THE JURY IS STILL VERY MUCH OUT ON WHETHER THIS PRECIPITATION
WILL BE LEGITIMATE LIGHT MEASURABLE SNOW...OR JUST GLORIFIED
FLURRIES...SO FOR NOW WILL KEEP POPS BELOW LIKELY TERRITORY
BARRING FURTHER EVIDENCE THAT MIGHT SUGGEST AN INCREASE IS
WARRANTED. EVEN IF THE FULL POTENTIAL OF THIS MORNING SNOW BAND IS
REALIZED...WOULD BE FAIRLY SURPRISED TO SEE ANY LOCATION REPORT
MORE THAN ONE-HALF INCH. CLOSELY FOLLOWING REFLECTIVITY TRENDS
FROM HIGHER RES MODELS SUCH AS THE HRRR AND 00Z 4KM
WRF-NMM...ANTICIPATE A GRADUAL EASTWARD SHIFT OF THE SNOW/FLURRY
BAND THIS MORNING...AND LIKELY DEPARTING THE NORTHEAST CWA BY MID-
DAY. ALTHOUGH MAY LATER REGRET THIS MOVE...OPTED TO PULL ALL
MENTION OF PRECIP FROM THE 1PM-7PM AFTERNOON TIME FRAME ACROSS THE
ENTIRE CWA...AS THE INITIAL SNOW BAND SHOULD BE DISSIPATED OR
MOVED OFF TO THE EAST-SOUTHEAST BY THEN...WHILE THE NEXT UPSTREAM
PRECIPITATION CHANCE SHOULD STILL BE JUST OFF TO THE WEST.
ALTHOUGH THE DAY AS A WHOLE SHOULD AVERAGE MOSTLY CLOUDY IN MOST
AREAS...COULD ACTUALLY SEE A FEW HOURS OF PARTIAL SUNSHINE AROUND
MID-DAY IN SOME AREAS IN BETWEEN SYSTEMS. OTHERWISE...THE BIGGEST
CHANGE TO TODAY/S FORECAST INVOLVED A ROUGHLY 5-DEGREE INCREASE TO
HIGH TEMPERATURES IN ALL BUT FAR NORTHEAST AREAS...AS THE LACK OF
AFTERNOON PRECIPITATION AND POTENTIALLY FILTERED SUNSHINE NOW
LOOKS TO HELP BOOST READINGS WELL INTO THE 40S ACROSS THE MAJORITY
OF THE CWA...WITH FAR SOUTHERN/SOUTHWEST AREAS POSSIBLY CRACKING
50. WILL HOWEVER KEEP KEEP THE FAR NORTHEAST AROUND THE
POLK/EASTERN NANCE/YORK COUNTY AREA DOWN IN THE UPPER 30S GIVEN
THE EXPECTATION OF CLOUDS HOLDING FIRMER THERE.
TURNING TO THE NIGHT PERIOD 7PM-7AM...AGAIN TOOK A BEST STAB AT
3-HOUR POP/WX GRIDS. ALTHOUGH POPS WERE RAISED INTO 60 PERCENT
LIKELY RANGE ACROSS MUCH OF THE AREA FOR AT LEAST A PORTION OF THE
NIGHT...ITS VERY POSSIBLE THAT POPS WILL NEED CRANKED UP MORE AS
CONFIDENCE INCREASES IN AT LEAST LIGHT SNOW ACCUMULATIONS.
ALOFT...THE PRIMARY INSTIGATOR IS A PROGRESSIVE...OPEN AND FAIRLY
LOW AMPLITUDE MID LEVEL SHORTWAVE TROUGH SWINGING WEST-EAST ACROSS
THE CENTRAL PLAINS ALONG THE SOUTHEAST PERIPHERY OF ITS PARENT
LARGER SCALE LOW CENTERED OVER THE NORTHERN ROCKIES. ALTHOUGH
THERE ARE STILL PLENTY OF MIXED MESSAGES REGARDING HOW QUICKLY
THIS PRECIPITATION MOVES INTO THE CWA...WITH SOME MODELS
SUGGESTING IT COULD EVEN MOVE INTO FAR WESTERN COUNTIES BEFORE 7
PM...HAVE TRIED TO FOLLOW THE REFLECTIVITY PROG OF THE 00Z WRF-NMM
FAIRLY CLOSELY. AS A RESULT...HAVE FOCUSED THE HIGHEST POPS ACROSS
THE WESTERN 1/2 OF THE CWA PRIOR TO 10 PM...AND THEN BRINGING
INCREASED CHANCES ACROSS THE REMAINDER OF THE AREA
THEREAFTER...AND THEN GRADUALLY DECREASING POPS FROM SOUTHWEST-
NORTHEAST ESPECIALLY BETWEEN 4 AM AND SUNRISE. ALTHOUGH ANTICIPATE
LIGHT TO BRIEFLY MODERATE SNOW TO BE THE MAIN PRECIP-TYPE...OPTED
TO MENTION A RAIN-SNOW MIX EARLY IN THE EVENING TO ACCOUNT FOR
STILL FAIRLY-WARM SURFACE TEMPS. SOME BRIEF SLEET IS NOT OUT OF
THE QUESTION IN SOME PLACES EITHER...BUT OVERALL THIS LOOKS LIKE
MAINLY SNOW AFTER NIGHTFALL AND WILL NOT INSERT ANY SLEET MENTION
AT THIS TIME. BETWEEN MIDNIGHT AND SUNRISE...THERE ARE STILL SOME
VALID CONCERNS FOR LIGHT DRIZZLE/FREEZING DRIZZLE DEVELOPING FOR
AT LEAST A FEW HOURS AS DEEPER MID LEVEL SATURATION MOVES OFF TO
THE EAST WHILE THE LOWEST FEW THOUSAND FEET REMAIN SATURATED PER
LOW LEVEL RELATIVE HUMIDITY PROGS FROM THE NAM. THE NAM ALSO SPITS
OUT ITS TELLTALE LIGHT/BLOTCHY QPF SIGNATURE INDICATIVE OF DRIZZLE
ACROSS MUCH OF THE CWA ESPECIALLY BETWEEN 4AM-7AM. GIVEN THE
EXPECTATION OF CONSIDERABLE CLOUD COVER...LOW TEMPS WERE RAISED A
FEW DEGREES FROM PREVIOUS FORECAST INTO THE MID-UPPER 20S ACROSS
MOST OF THE CWA...AND ITS ENTIRELY POSSIBLE THAT SOME AREAS
ESPECIALLY ACROSS THE SOUTHWESTERN CWA MAY BARELY DROP BELOW
FREEZING DURING THE TIME THAT DRIZZLE COULD FALL...THUS MITIGATING
ANY IMPACTS. THE THINKING AT THIS TIME HOWEVER IS THAT THE SNOW
WILL PROBABLY BE THE BIGGER STORY IMPACT-WISE THAN ANY FREEZING
DRIZZLE LINGERING THEREAFTER. ALTHOUGH CONFIDENCE IN SPECIFIC SNOW
AMOUNTS IS ADMITTEDLY SHAKY...HAVE GENERALLY PAINTED THE
SOUTHWESTERN CWA WITH 0.5 TO 0.9-INCH THROUGH SUNRISE FRIDAY
MORNING...WITH SLIGHTLY HIGHER AMOUNTS OF 1 INCH TO POSSIBLY 1.5
INCHES TARGETING THE NORTHEAST 1/2 OF THE CWA. AGAIN...THIS SETUP
BEARS WATCHING...BUT ITS STILL A TOUGH CALL TO SAY WHETHER THIS
COMBINATION OF LIGHT SNOW ACCUMULATION AND POSSIBLY LIGHT FREEZING
DRIZZLE WILL BE IMPACTFUL ENOUGH TO ULTIMATELY WARRANT A WINTER
WEATHER ADVISORY.
.LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 510 AM CDT THU MAR 21 2013
WE BEGIN FRIDAY WITH FORECAST SOUNDINGS REVEALING A STARK LOSS OF
MID-LEVEL SATURATION...WHICH WILL GIVE US AT LEAST A SMALL CHANCE
OF FREEZING DRIZZLE/DRIZZLE AS THE DENDRITIC GROWTH ZONE SCOOTS
OFF TO THE NORTHEAST/EAST. WE COULD HOLD ON TO A SMALL CHANCE OF
SNOW IN THE NORTHEAST EARLY FRIDAY MORNING...BUT ANY SNOW AMOUNTS
WOULD BE MINIMAL. MEANWHILE...IN THE UPPER LEVELS...A STRONG 140+
JET WILL DIG ON THE BACKSIDE OF A DEVELOPING TROUGH OVER THE
INTERMOUNTAIN WEST. WE SHOULD EXPERIENCE AT LEAST A SHORT LULL
PERIOD FOR FRIDAY AFTERNOON INTO FRIDAY EVENING.
TWO DISTINCT MID-LEVEL CENTERS OF LOW PRESSURE ARE FORECAST TO
DEVELOP WITHIN THE AFOREMENTIONED TROUGH. THERE IS FAIR AGREEMENT
AMONG MODELS THAT BY SATURDAY MORNING...ONE LOW WILL BE NEAR THE
CANADIAN/MONTANA BORDER...AND THE OTHER IN WESTERN COLORADO OR
PERHAPS EASTERN UTAH...ACCORDING TO THE ECMWF. THE NAM KEEPS AN OPEN
WAVE OVER COLORADO...WITH THE CLOSED LOW IN WESTERN NORTH DAKOTA FOR
12Z SATURDAY. THE NAM INDICATES STRONG ISENTROPIC LIFT ON THE 295K
PLANE FOR LATE FRIDAY NIGHT INTO SATURDAY ACROSS THE CWA AHEAD OF
THE TROUGH/LOW...ESPECIALLY IN THE WEST AND SOUTH...SO I INCREASED
CHANCES OF SNOW FOR THIS PERIOD COMPARED TO THE PREVIOUS FORECAST
AND LATEST MODEL GUIDANCE VALUES. THE NAM RAKES THE TROUGH AXIS
ACROSS THE CWA BY SATURDAY LATE AFTERNOON/EVENING...BUT THE ECMWF
TAKES ITS TIME...WITH THE AXIS CROSSING LATE DURING THE OVERNIGHT
SATURDAY NIGHT AND THUS MAXIMIZED LARGE SCALE LIFT...WITH THE GFS IN
BETWEEN...BY THE MID-EVENING. THE TRACK OF THE 500 MB LOW IS
FORECAST ALONG THE SOUTHERN/SOUTHWESTERN PERIPHERY OF OUR CWA...WITH
THE 700 MB JUST TO THE SOUTH OF THE CWA. STILL LOOKS LIKE KANSAS
STANDS THE BETTER CHANCE OF RECEIVING MORE OF THE ACCUMULATING
SNOWFALL THAN THE NEBRASKA SIDE AND HAVE NOT DEVIATED MUCH AT ALL
FROM THE PREVIOUS FORECAST SNOW AMOUNTS. THE QUESTION OF TIMING
KEEPS AT LEAST SMALL CHANCES INTO SUNDAY MORNING...WITH FURTHER
COMPLICATIONS POSSIBLE WITH THE NORTHERN LOW HELPING TO SUBSEQUENT
ENERGY DOWN OUR WAY...AND THE JET STREAM JUST TO THE SOUTH...NOT TO
FAR AWAY.
WITH THE PROBABILITY OF SOME SNOW COVER AND COLD TEMPERATURES ALOFT
FOR SUNDAY...I LOWERED MAXIMUM TEMPERATURES FOR SUNDAY...BELOW
GUIDANCE VALUES.
BELOW NORMAL TEMPERATURES WILL BE THE RULE FOR THE ENTIRE LONG
TERM...WITH YET MORE SMALL CHANCES OF SNOW/RAIN BY WEDNESDAY AS THE
REAR RIGHT QUADRANT OF THE JET STREAK TO THE SOUTH NEARS THE CWA AND
THE NORTHERN LOW HEADS SOUTH AND APPROACHES THE REGION...WHICH IN
TURN...COULD MEAN MORE COOL AND UNSETTLED WEATHER BEYOND THE SCOPE
OF THE LONG TERM FORECAST.
&&
.AVIATION...(FOR THE 18Z TAF THROUGH 18Z FRIDAY AFTERNOON)
ISSUED AT 1255 PM CDT THU MAR 21 2013
EXPECT A BREEZY EAST SOUTHEAST WIND THIS AFTERNOON WITH ONLY
SCATTERED MID CLOUDS AS WE SIT BETWEEN STORM SYSTEMS. THE NEXT
STORM SYSTEM WILL TRACK INTO KGRI TONIGHT WITH LOWERING CEILINGS
THIS EVENING...PRIMARILY AFTER 8 PM. LIGHT SNOW MAY BREAK OUT BY
LATE EVENING AT KGRI...OR GENERALLY AFTER 10 PM. LIGHT SNOW WILL
BE MOST LIKELY BETWEEN 11 PM AND 5 AM WITH THE SNOW GENERALLY
DECREASING AND COMING TO AN END BY AROUND DAY BREAK. IFR
VISIBILITY AND CEILINGS ARE POSSIBLE TONIGHT DUE TO THE SNOW WITH
SNOW ACCUMULATIONS OF 1 TO 2 INCHES EXPECTED.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
KS...NONE.
&&
$$
SHORT TERM...PFANNKUCH
LONG TERM...HEINLEIN
AREA FORECAST DISCUSSION
NWS OMAHA/VALLEY NE
1250 PM CDT THU MAR 21 2013
.DISCUSSION...
UPDATED AGAIN FOR TEMPERATURE TRENDS...TO LOWER TEMPS IN THE
WESTERN CWA UNDER MOST SIGNIFICANT CLOUD BAND AND EARLIER AREA OF
LIGHT SNOW. TEMPS HAVE BEEN SUPPRESSED BY A FEW DEGREES THIS
MORNING...AND THOUGH DIURNAL WARMING SHOULD IMPROVE THIS
AFTERNOON...COLD START WILL LEAVE LIMITED TIME TO CLIMB PAST THE
LOWER TO MID 30S. ALSO TWEAKED PRECIP GRID...WITH JUST A SLIGHT
CHANCE FOR /MEASURABLE/ SNOW IN THE SOUTHERN COUNTIES OF SOUTHEAST
NEB...THOUGH AT THIS POINT WOULD MOSTLY EXPECT FLURRIES.
MAYES
&&
.AVIATION...
18Z TAFS FOR KOMA...KLNK...AND KOFK.
LIGHT SNOW WILL LINGER JUST A BIT LONGER AT KLNK...WITH ALL SITES
RETURNING TO VFR THIS AFTERNOON AS CLOUDS LINGER AROUND 4-6KFT.
CEILINGS WILL LOWER AFTER MIDNIGHT AS NEXT STORM SYSTEM
APPROACHES. WOULD EXPECT KOFK TO RECEIVE SNOW LONGEST AND WITH
MOST INTENSITY...FOLLOWED BY KOMA AND THEN KLNK. HAVE INCLUDED
PREVAILING LIGHT SNOW WITH TEMPO FOR MORE MODERATE SNOW AT ALL
SITES IN THE EARLY MORNING...WITH CIGS REMAINING AT MVFR THROUGH
18Z.
MAYES
&&
.PREV DISCUSSION... /ISSUED 946 AM CDT THU MAR 21 2013/
DISCUSSION...
HAVE UDPATED THE GRIDS FOR TRENDS WITH THE MORNING SNOW. INCREASED
POPS IN THE FAR SOUTH CWA AS HEAVIER BAND EXITS THE AREA...AND
ALSO EXPANDED POPS IN THE NORTHWEST CWA WHERE VIS IS DOWN TO ABOUT
1 MI WITH SOME SNOW. CONTINUED THE SHARP GRADIENT TO DRY
CONDITIONS IN THE EASTERN CWA...WITH EASTERLY WINDS BRINGING IN
DRY AIR. ADDITIONALLY...HAVE SPED THE EXIT OF THE SYSTEM TODAY AS
LIFT SLIDES TO THE SOUTH...WITH JUST A SMALL AREA OF CHANCE POPS
IN THE FAR SOUTHEAST CORNER OF NEB IN THE EARLY AFTERNOON AND ALL
CLEAR 21-00Z. FINALLY...HAVE TWEAKED TEMPERATURES AND DEWPOINTS
BOTH FOR HOURLY TRENDS AND TO TOUCH DOWN TEMPS A BIT IN THE
SOUTHERN CWA.
MAYES
PREV DISCUSSION... /ISSUED 337 AM CDT THU MAR 21 2013/
DISCUSSION...
FORECAST CHALLENGES FOR THIS FORECAST PACKAGE WILL INCLUDE TIMING
OF THE SNOW CHANCES TODAY...TONIGHT AND FRIDAY...SATURDAY INTO THE
EXTENDED...WILL IT BE MEASURABLE AND HOW MUCH?...WILL THERE BE
ANY PERIODS OF A MIX?...ALSO TEMPERATURES THROUGH THE PERIOD.
OUR OAX SOUNDING FROM 00Z WAS QUITE DRY WITH SOME HIGHER RH AT H5
AND H85...BUT ONLY 36 PERCENT OF NORMAL PRECIPITABLE WATER. THIS
WAS COMMON ACROSS THE ENTIRE MIDWEST...WITH THE CLOSEST NEAR NORMAL
PRECIPITABLE WATER AT RAPID CITY AND DODGE CITY.
A LOOP OF THE IR SATELLITE IMAGERY SHOWS A LOT GOING ON AND
DIFFERENT FLOWS ACROSS THE COUNTRY. THERE IS A STRONG AREA OF LOW
PRESSURE/WINTER SYSTEM OVER THE NORTHEAST U.S./GREAT LAKES. THE
TROF IN THE PACIFIC NORTHWEST SHOWS UP...AS WELL AS THE FETCH OF
TROPICAL MOISTURE FROM THE PACIFIC ACROSS THE SOUTHERN PLAINS. AT
H85...THE THERMAL GRADIENT SHOWS UP NICELY BETWEEN THE COLD SYSTEM
OFF TO OUR EAST...AND THE WARMER AIR WITH THE PACIFIC SYSTEM THAT
WILL AFFECT US INTO THE WEEKEND WITH -12 DEG C AT OMA AND +1C AT
LBF. AT THE SURFACE....SURFACE HIGH PRESSURE EXTENDED FROM THE
NORTHERN PLAINS THRU THE MISSOURI RIVER VALLEY INTO IOWA AND
MISSOURI. LOCALLY TEMPERATURES WERE IN THE TEENS AND 20S WITH
DEWPOINTS IN THE SINGLE DIGITS AND TEENS. AN AREA OF LOW PRESSURE
EXTENDED FROM WYOMING THROUGH COLORADO. TEMPERATURES WERE MUCH
WARMER IN WESTERN NEBRASKA WITH 30S AND 40S. AT 08Z...A NORTHWEST
TO SOUTHEAST BAND OF ECHOES HAS BEEN INCREASING AND SLIDING EAST. AT
08Z...SNOW WAS REACHING THE GROUND AT ANW AND TIF. HOW DOES THIS
MATCH OF WITH THE PROGS...THE NAM WAS DRY AND THE
SREF/GFS/EC/RAP/HRRR...ALL SHOWED SOME PRECIP IN THIS AREA TO
VARYING DEGREES.
THERE ARE THREE PERIODS WHEN WE MAY SEE LIGHT SNOW.
TODAY...TONIGHT INTO FRIDAY MORNING AND SATURDAY AFTERNOON INTO
SUNDAY...EACH PROGRESSIVELY MORE ORGANIZED.
THIS MORNING...THERE IS STRONG H85 WARM AIR ADVECTION ACROSS
KANSAS WITH A 50KT LOW LEVEL JET AND H7 WAA INTO NEBRASKA. THERE
IS SOME LIFT WITH A WEAK SHORTWAVE IN THE NORTHWEST FLOW...AND A
DECENT INCREASE MOISTURE. ACROSS PARTS OF EASTERN NEBRASKA. LOW
LEVEL DRY AIR IS IN PLACE...SO THE TOUGH CALL WILL BE WHERE TO
INCLUDE POPS...WHERE TO KEEP IT DRY AND IF IT WILL BE MEASURABLE.
IN GENERAL...THE SHORT RANGE MODELS BRING A NARROW BAND OF LIGHT
SNOW ACROSS PARTS OF EASTERN NEBRASKA WITH LITTLE OR NO
ACCUMULATION. THE RAP APPEARS OVERDONE. WILL INCLUDE HIGHEST POPS
IN THE WRN PART OF THE FORECAST AREA AND WILL LEAVE MAINLY DRY
PARTS OF NORTHEAST AND FAR EASTERN NEBRASKA INTO PARTS OF
SOUTHWEST IOWA. CLOUDS OR LACK OF THICKER CLOUDS WILL IMPACT
TEMPERATURES AND HAVE RAISED SOME OF THE HIGHS. HIGHS IN THE 30S
TO LOWER 40S.
TONIGHT AND FRIDAY MORNING LARGE SCALE LIFT OCCURS WITH A PIECE OF
ENERGY FROM THE PACIFIC NORTHWEST STORM SYSTEM ROTATING THROUGH
THE PLAINS WITH LIGHT SNOW SPREADING FROM WESTERN NEBRASKA INTO
EASTERN NEBRASKA TONIGHT AND MORE INTO WESTERN IOWA FRIDAY
MORNING...THEN WEAKENING. THERE COULD BE SOME LIGHT ACCUMULATIONS
AND FOR NOW HAVE MOST AMOUNTS AN INCH OR LESS.
THERE IS A BREAK IN THE PRECIPITATION LATER FRIDAY INTO EARLY
SATURDAY. THE H5 TROF MOVES INTO THE PLAINS SATURDAY/SATURDAY
NIGHT. THE NAM SEEMS TO BE THE OUTLIER WITH A STRONGER FAST CLOSED
LOW THAT TRACKS FARTHER NORTH. FOR NOW TRENDED WITH THE EC/GFS AND
HAVE THE HIGHEST POPS ACROSS THE SOUTHERN HALF OF THE FORECAST
AREA. THE PRECIPITATION SATURDAY COULD START AS A RAIN/SNOW MIX
BEFORE IT CHANGES OVER TO SNOW. THERE IS GOOD WRAP- AROUND
MOISTURE IN THE DENDRITIC LAYER SO THIS WILL NEED TO BE WATCHED.
IT IS EARLY TO PUT AMOUNTS ON THE SAT/SUN STORM AS THE TRACK MAY
SHIFT...THE EC/GFS ARE MORE IN THE 2 TO 6 INCH CATEGORY FOR THE
SOUTHERN HALF OF THE FORECAST AREA WITH THE HEAVY SNOW IN KANSAS
AND MISSOURI. WHILE THE NAM HAS HIGHER AMOUNTS FARTHER NORTH.
HEADLINES WILL NEED TO BE CONSIDERED IF THE SYSTEM DOES NOT TRACK
FARTHER SOUTH DUE TO THE COMBINATION OF BRISK WINDS AND SNOW.
ZAPOTOCNY
&&
.OAX WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
IA...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS RALEIGH NC
300 PM EDT THU MAR 21 2013
.SYNOPSIS...
COLD HIGH PRESSURE WILL BUILD INTO THE REGION FROM THE NORTHWEST
THROUGH FRIDAY. A COMPLEX LOW PRESSURE SYSTEM WILL DEVELOP OVER THE
DEEP SOUTH ON SATURDAY...THEN TRACK NORTHEAST INTO THE CAROLINAS AND
MID ATLANTIC ON SUNDAY.
&&
.NEAR TERM /THROUGH FRIDAY NIGHT/...
AS OF 300 PM THURSDAY...
THROUGH TONIGHT:
SURFACE INSOLATION AND ANOMALOUSLY COLD TEMPS ALOFT (H85 TEMP OF
-10C) DUE TO STRONG COLD ADVECTION EARLIER THIS MORNING HAS RESULTED
IN VERY STEEP LOW-LEVEL LAPSE RATES AND MARGINAL DIURNAL
DESTABILIZATION THIS AFTERNOON...WITH PERHAPS 50-100 J/KG OF SHALLOW
MLCAPE (EQ LEVEL 7-10 KFT) AS OF 18Z. A POTENT SHORTWAVE (PER WV
IMAGERY AND THE LATEST RAP DATA) WAS CENTERED OVER WV/VA AT
18Z...ROUNDING THE BASE OF AN UNSEASONABLY COLD CYCLONIC GYRE
CENTERED OVER NEW ENGLAND. DPVA ASSOCIATED WITH THIS FEATURE WILL
BEGIN TO WANE OVER THE NORTHERN PIEDMONT AND NE COASTAL PLAIN OVER
THE NEXT SEVERAL HOURS AS THE SHORTWAVE PROGRESSES EAST TO THE
DELMARVA. AS A RESULT...ISOLD SNOW SHOWERS ASSOC/W DPVA IN THE
PRESENCE OF MARGINAL INSTABILITY (EXTENDING INTO THE ICE NUCLEATION
ZONE) WILL GRADUALLY WANE AND END OVER THE NEXT FEW HOURS...BETWEEN
18-20Z. NW WINDS WILL INCREASE TO 10-15 MPH SUSTAINED WITH GUSTS UP
TO 25 MPH DURING THE 19-22Z TIME-FRAME AS PRESSURE RISES ENSUE IN
THE WAKE OF THE SHORTWAVE. WINDS WILL GRADUALLY DIMINISH THIS
EVENING INTO TONIGHT AS THE NOCTURNAL INVERSION DEVELOPS AND THE
MSLP GRADIENT WEAKENS FROM W-E. GIVEN CLEAR SKIES AND AN ANOMALOUSLY
COLD/DRY AIRMASS IN PLACE...EXPECT LOWS WELL BELOW NORMAL...PERHAPS
NEAR RECORD COLD FOR MARCH 22. EXACTLY HOW MUCH TEMPS FALL WILL
DEPEND PRIMARILY ON WHEN WINDS DIMINISH...WHICH SHOULD OCCUR EARLIER
IN THE WESTERN PIEDMONT AND LATEST IN THE COASTAL PLAIN. WILL
INDICATE LOWS RANGING FROM THE LOWER TO MID 20S...COLDEST IN RURAL
AND LOW-LYING AREAS...ESP IN THE WESTERN PIEDMONT.
FRIDAY AND FRIDAY NIGHT:
HEIGHTS WILL RISE DURING THE DAY FRIDAY AND FLOW ALOFT WILL BECOME
INCREASINGLY UNIDIRECTIONAL AS THE ANOMALOUSLY COLD CYCLONIC GYRE
CENTERED OVER NEW ENGLAND SHIFTS TOWARD THE CANADIAN MARITIMES.
EXPECT SUNNY SKIES AND WARMER TEMPS THAN TODAY IN ASSOC/W LOW-LEVEL
WARM ADVECTION FROM THE WEST/WSW THROUGHOUT THE DAY. WILL INDICATE
HIGHS IN THE LOWER/MID 50S...SIMILAR TO MOS GUIDANCE...THOUGH IT IS
POSSIBLE THAT A FEW LOCATIONS COULD REACH THE UPPER 50S GIVEN FULL
SUN. EXPECT INCREASING MID/UPPER LEVEL CLOUD COVER FRIDAY NIGHT AS
MOISTURE ADVECTS DOWNSTREAM OF PRECIPITATION EXPECTED TO DEVELOP IN
VICINITY OF A STRENGTHENING FRONTAL ZONE ALONG THE GULF COAST...IN
ADVANCE OF AN UPPER LEVEL TROUGH DIGGING SOUTHEAST INTO THE ROCKIES.
THE BEST LOW-LEVEL MOISTURE RETURN AND WARM ADVECTION IS EXPECTED TO
REMAIN WEST AND SOUTHWEST OF CENTRAL NC...THOUGH IT IS POSSIBLE THAT
MID-LEVEL FRONTOGENESIS MAY ALSO CONTRIBUTE TO ASCENT OVER WESTERN
PORTIONS OF THE STATE. GIVEN THE DRY ANTECEDENT AIRMASS IN PLACE...
AT THIS TIME PREFER TO KEEP THE FORECAST DRY THROUGH FRIDAY NIGHT.
GIVEN INCREASING MID/UPPER LEVEL CLOUD COVER FROM SW-NE...EXPECT
LOWS WARMER THAN TONIGHT...RANGING FROM 30-37F...COOLEST IN RURAL
AND LOW-LYING AREAS EAST AND NE OF THE TRIANGLE. -VINCENT
&&
.SHORT TERM /SATURDAY THROUGH SUNDAY/...
AS OF 1230 PM THURSDAY...
A COLD RAIN EXPECTED LATE SATURDAY THROUGH SUNDAY...
STRONG HIGH LATITUDE BLOCKING DOWNSTREAM AND THE STRONGLY NEGATIVE
PHASE OF BOTH THE ARCTIC OSCILLATION (AO) AND NORTH ATLANTIC
OSCILLATION (NAO) ARE FORECAST TO CONTINUE THROUGH EARLY NEXT
WEEK...KEEPING TEMPERATURES MUCH BELOW NORMAL (LIKELY 15-20 DEGREES)
THROUGH SUNDAY. SEVERAL MID/UPPER DISTURBANCES WILL MOVE EAST OUT OF
THE ROCKIES IN SUPPRESSED FASHION ACROSS THE DEEP SOUTH...WITH THE
POLAR FRONT POSITIONED WELL SOUTH (ALONG THE GULF OF MEXICO).
THE MOST SUBSTANTIAL SHORTWAVE IS FORECAST TO EMERGE ACROSS THE
SOUTHERN PLAINS SUNDAY AND TRACK GENERALLY EAST ACROSS THE TENNESSEE
VALLEY AND CENTRAL APPALACHIANS LATE IN THE WEEKEND INTO EARLY
MONDAY. THIS SHOULD LEAD TO A "MILLER-B" SURFACE LOW PRESSURE
EVOLUTION AND HYBRID COLD AIR DAMMING EVENT SUNDAY INTO EARLY
MONDAY. AHEAD OF THIS WAVE...STRENGTHENING SSW FLOW AND WARM
ADVECTION BETWEEN H925 AND H7 SHOULD SPREAD SOME LIGHT PRECIP ACROSS
THE SOUTHEAST UNITED STATES AS EARLY AS SATURDAY AS THE 850MB FRONT
LIFTS NORTH ACROSS AL/GA/SC. HOWEVER... MODELS CONTINUE TO DISAGREE
ON THE NORTHWARD EXTENT OF MEASURABLE PRECIPITATION.
THE LATEST NAM AND GFS RUNS CONTINUE TO BRING SOME LIGHT MEASURABLE
RAIN INTO OUR WESTERN AND SOUTHERN COUNTIES LATE FRIDAY NIGHT AND
EARLY SATURDAY. THIS WOULD BE ASSOCIATED WITH A LEAD DISTURBANCE AND
PARTIAL THICKNESSES BECOME WARM ENOUGH FOR ALL RAIN. THE EC HAS NOT
BEEN AS AGGRESSIVE WITH THE LIGHT MEASURABLE RAIN WITH THE LEAD WAVE
THIS FAR NORTHEAST...BUT GIVEN THAT THE NAM AND GFS HAVE HAD 4
CONSECUTIVE RUNS WITH THE SAME FORECAST OF LIGHT QPF...WE WILL KEEP
LOW END CHANCES FOR THE SOUTHERN ZONES (ALBEMARLE TO FAYETTEVILLE)
LATE FRIDAY NIGHT INTO MID-DAY SATURDAY. OTHERWISE...GIVEN THE
EXTENT OF THE DRYNESS THE ANTECEDENT AIR MASS IS EXPECTED TO BE...
PREFER TO STICK WITH THE DRY EC OVER THE NORTHERN COUNTIES THROUGH
SATURDAY. HIGHS SATURDAY SHOULD BE FAIRLY UNIFORM ACROSS THE
REGION...WITH THE POSSIBLE LIGHT RAIN EARLY IN THE SOUTH...HIGHS
SHOULD BE ONLY IN THE 50-55 RANGE MOST AREAS. IF SOME LIGHT RAIN IS
MEASURED...TEMPS SHOULD BE EVEN COOLER.
FOR SATURDAY NIGHT AND SUNDAY...EXPECT RAIN TO OVERSPREAD/DEVELOP
NORTHWARD ACROSS OUR REGION WITH THE APPROACH OF THE STRONG
MID/UPPER LEVEL WAVE FROM THE WEST. THE GFS AND NAM CONTINUE TO
DRIVE A STRENGTHENING SURFACE WAVE NE THROUGH THE TENNESSEE VALLEY
INTO THE LOWER OHIO VALLEY SAT NIGHT AND SUNDAY...WITH SECONDARY
BECOMING PRIMARY LOW PRESSURE DEVELOPMENT OFF THE SC COAST SUNDAY.
WITH THE LATTER EXPECTED TO TRACK ALONG THE COAST OF NC LATE SUNDAY
INTO SUNDAY NIGHT...HYBRID CAD WILL BECOME ENTRENCHED OVER CENTRAL
NC THROUGHOUT THE EVENT.
SENSIBLE WEATHER WILL INCLUDE...RAIN DEVELOPING SATURDAY NIGHT WITH
LOWS OF 35-40. RAIN TAPERING TO AREAS OF DRIZZLE LATE SUNDAY. COLD
WITH HIGHS IN THE 40S EXCEPT UPPER 30S NW. QPF ON THE ORDER OF 0.50
TO 0.75 EXPECTED (MAINLY BETWEEN 06Z AND 15Z SUNDAY...TAPERING TO
LIGHT 0.10 AMOUNTS SUNDAY AFTERNOON). STORM TOTALS SHOULD REMAIN
BELOW 1 INCH. STRONG CAA WILL FOLLOW THE STORM INTO NC FROM THE NW
BEGINNING LATE SUNDAY NIGHT. LOWS 35-40 (CLEARING LATE SUNDAY
NIGHT).
&&
.LONG TERM /MONDAY THROUGH THURSDAY/...
AS OF 1230 PM THURSDAY...
STRONG CAA ON MONDAY IN THE REAR OF THE DEPARTING STORM MOVING OUT
INTO THE ATLANTIC WILL KEEP HIGHS ONLY IN THE 40S TO LOWER 50S
(15-20 DEGREES BELOW NORMAL). NW WINDS 15-20 MPH WILL GUST TO 30
MPH. SOME VERY LIGHT SNOW SHOWERS MAY OCCUR ESPECIALLY IN AREAS N-E
OF RALEIGH (NORTHERN COASTAL PLAIN)... BUT NOTHING SIGNIFICANT
EXPECTED. OTHERWISE... PARTLY SUNNY AND WINDY.
CLEAR AND COLD MONDAY NIGHT SHOULD YIELD LOWS IN THE UPPER 20S AND
LOWER 30S (10-15 DEGREES BELOW NORMAL).
TUESDAY THROUGH THURSDAY... A MOSTLY DRY AND CHILLY PATTERN SHOULD
CONTINUE WITH THE DEEP TROUGH EXPECTED TO RELAX A BIT MID-LATE WEEK.
HOWEVER...A STRONG SURFACE HIGH SHOULD EXTEND FROM THE NORTHERN
PLAINS DEEP INTO THE GULF COAST STATES ENSURING CAA WILL BE
DELIVERED DEEP INTO THE SE STATES THROUGH THE PERIOD.
MOSTLY CLEAR/MOSTLY SUNNY SKIES EXPECTED MONDAY NIGHT THROUGH
THURSDAY. LOWS GENERALLY AT OR SLIGHTLY BELOW 32. HIGHS 50-55.
THESE READINGS WILL REMAIN AROUND 15 DEGREES BELOW NORMAL.
&&
.AVIATION /18Z THURSDAY THROUGH TUESDAY/...
AS OF 115 PM THURSDAY...
24-HR TAF PERIOD:
ASIDE FROM A BRIEF PERIOD OF MVFR CONDITIONS ASSOCIATED WITH SNOW
SHOWERS AT THE RWI TERMINAL BETWEEN 16-19Z...VFR CONDITIONS WILL
RULE THROUGH THE TAF PERIOD. NORTHWEST WINDS WILL BECOME SUSTAINED
AT 10-15 KT WITH GUSTS UP TO 20-25 KT LATER THIS AFTERNOON... BEFORE
DECREASING TO 5-10 KT AROUND SUNSET THIS EVENING. WINDS WILL BECOME
LIGHT/VARIABLE TONIGHT AND REMAIN LIGHT/VARIABLE THROUGH 15-18Z
FRIDAY.
LOOKING AHEAD:
VFR CONDITIONS WILL PREVAIL FRIDAY THROUGH EARLY FRIDAY NIGHT...WITH
AN INCREASING CHANCE FOR MVFR CEILINGS BETWEEN MIDNIGHT AND SUNRISE
SATURDAY MORNING IN ASSOC/W AN INCREASINGLY MOIST SOUTHWESTERLY
LOW-LEVEL RETURN FLOW FROM THE GULF OF MEXICO. WIDESPREAD ADVERSE
AVIATION CONDITIONS ARE EXPECTED OVER THE WEEKEND (PRIMARILY LATE
SAT NIGHT THROUGH SUNDAY) AS A DEVELOPING LOW PRESSURE SYSTEM OVER
THE DEEP SOUTH TRACKS NORTHEAST INTO THE CAROLINAS AND MID-ATLANTIC.
AT THIS TIME...THE BEST CHANCE FOR RAIN AND IFR CONDITIONS IS
EXPECTED BETWEEN 12Z SUN AND 06Z MON. -VINCENT
&&
.FIRE WEATHER...
THE SPECIAL WEATHER STATEMENT FOR INCREASED FIRE DANGER WILL BE
ALLOWED TO REMAIN IN EFFECT THROUGH 00Z THIS EVENING IN ASSOC/W RH
VALUES AT OR BELOW 25% AND NW WINDS SUSTAINED AT 10-15 MPH WITH
GUSTS UP TO 25 MPH DURING THE MID/LATE AFTERNOON HOURS. -VINCENT
&&
.RECORD LOWS...
MARCH 22:
RDU: 22F IN 1986
GSO: 22F IN 1986
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...VINCENT
NEAR TERM...VINCENT
SHORT TERM...BADGETT
LONG TERM...BADGETT
AVIATION...VINCENT
FIRE WEATHER...VINCENT
AREA FORECAST DISCUSSION
NWS RALEIGH NC
159 PM EDT THU MAR 21 2013
.SYNOPSIS...
COLD HIGH PRESSURE WILL BUILD INTO THE REGION FROM THE NORTHWEST
THROUGH FRIDAY. A COMPLEX LOW PRESSURE SYSTEM WILL DEVELOP OVER THE
DEEP SOUTH ON SATURDAY...THEN TRACK NORTHEAST INTO THE CAROLINAS AND
MID ATLANTIC ON SUNDAY.
&&
.NEAR TERM /THROUGH FRIDAY NIGHT/...
AS OF 200 PM THURSDAY...
THROUGH TONIGHT:
SURFACE INSOLATION AND ANOMALOUSLY COLD TEMPS ALOFT (H85 TEMP OF
-10C) DUE TO STRONG COLD ADVECTION EARLIER THIS MORNING HAS RESULTED
IN VERY STEEP LOW-LEVEL LAPSE RATES AND MARGINAL DIURNAL
DESTABILIZATION THIS AFTERNOON...WITH PERHAPS 50-100 J/KG OF SHALLOW
MLCAPE (EQ LEVEL 7-10 KFT) AS OF 18Z. A POTENT SHORTWAVE (PER WV
IMAGERY AND THE LATEST RAP DATA) WAS CENTERED OVER WV/VA AT
18Z...ROUNDING THE BASE OF AN UNSEASONABLY COLD CYCLONIC GYRE
CENTERED OVER NEW ENGLAND. DPVA ASSOCIATED WITH THIS FEATURE WILL
BEGIN TO WANE OVER THE NORTHERN PIEDMONT AND NE COASTAL PLAIN OVER
THE NEXT SEVERAL HOURS AS THE SHORTWAVE PROGRESSES EAST TO THE
DELMARVA. AS A RESULT...ISOLD SNOW SHOWERS ASSOC/W DPVA IN THE
PRESENCE OF MARGINAL INSTABILITY (EXTENDING INTO THE ICE NUCLEATION
ZONE) WILL GRADUALLY WANE AND END OVER THE NEXT FEW HOURS...BETWEEN
18-20Z. NW WINDS WILL INCREASE TO 10-15 MPH SUSTAINED WITH GUSTS UP
TO 25 MPH DURING THE 19-22Z TIME-FRAME AS PRESSURE RISES ENSUE IN
THE WAKE OF THE SHORTWAVE. WINDS WILL GRADUALLY DIMINISH THIS
EVENING INTO TONIGHT AS THE NOCTURNAL INVERSION DEVELOPS AND THE
MSLP GRADIENT WEAKENS FROM W-E. GIVEN CLEAR SKIES AND AN ANOMALOUSLY
COLD/DRY AIRMASS IN PLACE...EXPECT LOWS WELL BELOW NORMAL...PERHAPS
NEAR RECORD COLD FOR MARCH 22. EXACTLY HOW MUCH TEMPS FALL WILL
DEPEND PRIMARILY ON WHEN WINDS DIMINISH...WHICH SHOULD OCCUR EARLIER
IN THE WESTERN PIEDMONT AND LATEST IN THE COASTAL PLAIN. WILL
INDICATE LOWS RANGING FROM THE LOWER TO MID 20S...COLDEST IN RURAL
AND LOW-LYING AREAS...ESP IN THE WESTERN PIEDMONT. -VINCENT
FOR FRIDAY/FRIDAY NIGHT: A PORTION OF THE SURFACE RIDGE EXTENDING
THROUGH THE CAROLINAS FROM THE NW BREAKS OFF OVER THE SOUTHEAST
COAST... RESULTING IN NW AND WNW WINDS SWINGING AROUND TO
SOUTHWESTERLY BUT REMAINING LIGHT. THE FRONTAL ZONE LOCATED ALONG FL
AND THE NORTHERN GULF TODAY WILL START TO HEAD BACK NORTH AND NNE AS
A WARM FRONT... DRIVEN BY AN APPROACHING TROUGH AND FALLING HEIGHTS
OVER THE DESERT SOUTHWEST AND LOWERING SURFACE PRESSURES OVER TX.
EXPECT PLENTY OF SUNSHINE THROUGH MUCH OF FRIDAY WITH DEEP DRY AND
STABLE AIR IN PLACE... THEN INCREASING ISENTROPIC UPGLIDE FROM THE
SW SHOULD RESULT IN QUICKLY INCREASING AND THICKENING CLOUDS FRIDAY
EVENING AND NIGHT AS HIGHER PRECIP WATER (150% OF NORMAL) SPREADS
INTO NC FROM THE SSW. OVERALL FORCING FOR ASCENT REMAINS MUTED...
AND THE COLUMN DOES NOT COMPLETELY SATURATE ACCORDING TO GFS/NAM
FORECAST SOUNDINGS... BUT THE GFS DEPICTS FAIRLY STRONG MOIST
UPGLIDE AT 295-310K BY 12Z SATURDAY SUCH IT PRODUCES ONE TO TWO
TENTHS OF AN INCH OF PRECIP OVER THE SRN CWA. EVEN THE NAM HAS A 30
KT SWRLY LOW LEVEL JET NOSING INTO THE NORTHWARD-RETREATING WARM
FRONT AS IT HEADS INTO SRN NC. WILL BRING IN A SMALL CHANCE OF RAIN
OVER THE SW AND FAR SRN CWA LATE FRIDAY NIGHT. THE LOW LEVEL TEMP
PROFILE SUPPORTS AN UPWARD NUDGE TO HIGHS... TO 52-55 DEGREES. THIS
IS ON THE COOL SIDE OF STATISTICAL GUIDANCE AND MAY STILL BE TOO
COOL IF GUIDANCE TRENDS ARE CORRECT. LOWS 32-39. -GIH
&&
.SHORT TERM /SATURDAY THROUGH SUNDAY/...
AS OF 1230 PM THURSDAY...
A COLD RAIN EXPECTED LATE SATURDAY THROUGH SUNDAY...
STRONG HIGH LATITUDE BLOCKING DOWNSTREAM AND THE STRONGLY NEGATIVE
PHASE OF BOTH THE ARCTIC OSCILLATION (AO) AND NORTH ATLANTIC
OSCILLATION (NAO) ARE FORECAST TO CONTINUE THROUGH EARLY NEXT
WEEK...KEEPING TEMPERATURES MUCH BELOW NORMAL (LIKELY 15-20 DEGREES)
THROUGH SUNDAY. SEVERAL MID/UPPER DISTURBANCES WILL MOVE EAST OUT OF
THE ROCKIES IN SUPPRESSED FASHION ACROSS THE DEEP SOUTH...WITH THE
POLAR FRONT POSITIONED WELL SOUTH (ALONG THE GULF OF MEXICO).
THE MOST SUBSTANTIAL SHORTWAVE IS FORECAST TO EMERGE ACROSS THE
SOUTHERN PLAINS SUNDAY AND TRACK GENERALLY EAST ACROSS THE TENNESSEE
VALLEY AND CENTRAL APPALACHIANS LATE IN THE WEEKEND INTO EARLY
MONDAY. THIS SHOULD LEAD TO A "MILLER-B" SURFACE LOW PRESSURE
EVOLUTION AND HYBRID COLD AIR DAMMING EVENT SUNDAY INTO EARLY
MONDAY. AHEAD OF THIS WAVE...STRENGTHENING SSW FLOW AND WARM
ADVECTION BETWEEN H925 AND H7 SHOULD SPREAD SOME LIGHT PRECIP ACROSS
THE SOUTHEAST UNITED STATES AS EARLY AS SATURDAY AS THE 850MB FRONT
LIFTS NORTH ACROSS AL/GA/SC. HOWEVER... MODELS CONTINUE TO DISAGREE
ON THE NORTHWARD EXTENT OF MEASURABLE PRECIPITATION.
THE LATEST NAM AND GFS RUNS CONTINUE TO BRING SOME LIGHT MEASURABLE
RAIN INTO OUR WESTERN AND SOUTHERN COUNTIES LATE FRIDAY NIGHT AND
EARLY SATURDAY. THIS WOULD BE ASSOCIATED WITH A LEAD DISTURBANCE AND
PARTIAL THICKNESSES BECOME WARM ENOUGH FOR ALL RAIN. THE EC HAS NOT
BEEN AS AGGRESSIVE WITH THE LIGHT MEASURABLE RAIN WITH THE LEAD WAVE
THIS FAR NORTHEAST...BUT GIVEN THAT THE NAM AND GFS HAVE HAD 4
CONSECUTIVE RUNS WITH THE SAME FORECAST OF LIGHT QPF...WE WILL KEEP
LOW END CHANCES FOR THE SOUTHERN ZONES (ALBEMARLE TO FAYETTEVILLE)
LATE FRIDAY NIGHT INTO MID-DAY SATURDAY. OTHERWISE...GIVEN THE
EXTENT OF THE DRYNESS THE ANTECEDENT AIR MASS IS EXPECTED TO BE...
PREFER TO STICK WITH THE DRY EC OVER THE NORTHERN COUNTIES THROUGH
SATURDAY. HIGHS SATURDAY SHOULD BE FAIRLY UNIFORM ACROSS THE
REGION...WITH THE POSSIBLE LIGHT RAIN EARLY IN THE SOUTH...HIGHS
SHOULD BE ONLY IN THE 50-55 RANGE MOST AREAS. IF SOME LIGHT RAIN IS
MEASURED...TEMPS SHOULD BE EVEN COOLER.
FOR SATURDAY NIGHT AND SUNDAY...EXPECT RAIN TO OVERSPREAD/DEVELOP
NORTHWARD ACROSS OUR REGION WITH THE APPROACH OF THE STRONG
MID/UPPER LEVEL WAVE FROM THE WEST. THE GFS AND NAM CONTINUE TO
DRIVE A STRENGTHENING SURFACE WAVE NE THROUGH THE TENNESSEE VALLEY
INTO THE LOWER OHIO VALLEY SAT NIGHT AND SUNDAY...WITH SECONDARY
BECOMING PRIMARY LOW PRESSURE DEVELOPMENT OFF THE SC COAST SUNDAY.
WITH THE LATTER EXPECTED TO TRACK ALONG THE COAST OF NC LATE SUNDAY
INTO SUNDAY NIGHT...HYBRID CAD WILL BECOME ENTRENCHED OVER CENTRAL
NC THROUGHOUT THE EVENT.
SENSIBLE WEATHER WILL INCLUDE...RAIN DEVELOPING SATURDAY NIGHT WITH
LOWS OF 35-40. RAIN TAPERING TO AREAS OF DRIZZLE LATE SUNDAY. COLD
WITH HIGHS IN THE 40S EXCEPT UPPER 30S NW. QPF ON THE ORDER OF 0.50
TO 0.75 EXPECTED (MAINLY BETWEEN 06Z AND 15Z SUNDAY...TAPERING TO
LIGHT 0.10 AMOUNTS SUNDAY AFTERNOON). STORM TOTALS SHOULD REMAIN
BELOW 1 INCH. STRONG CAA WILL FOLLOW THE STORM INTO NC FROM THE NW
BEGINNING LATE SUNDAY NIGHT. LOWS 35-40 (CLEARING LATE SUNDAY
NIGHT).
&&
.LONG TERM /MONDAY THROUGH THURSDAY/...
AS OF 1230 PM THURSDAY...
STRONG CAA ON MONDAY IN THE REAR OF THE DEPARTING STORM MOVING OUT
INTO THE ATLANTIC WILL KEEP HIGHS ONLY IN THE 40S TO LOWER 50S
(15-20 DEGREES BELOW NORMAL). NW WINDS 15-20 MPH WILL GUST TO 30
MPH. SOME VERY LIGHT SNOW SHOWERS MAY OCCUR ESPECIALLY IN AREAS N-E
OF RALEIGH (NORTHERN COASTAL PLAIN)... BUT NOTHING SIGNIFICANT
EXPECTED. OTHERWISE... PARTLY SUNNY AND WINDY.
CLEAR AND COLD MONDAY NIGHT SHOULD YIELD LOWS IN THE UPPER 20S AND
LOWER 30S (10-15 DEGREES BELOW NORMAL).
TUESDAY THROUGH THURSDAY... A MOSTLY DRY AND CHILLY PATTERN SHOULD
CONTINUE WITH THE DEEP TROUGH EXPECTED TO RELAX A BIT MID-LATE WEEK.
HOWEVER...A STRONG SURFACE HIGH SHOULD EXTEND FROM THE NORTHERN
PLAINS DEEP INTO THE GULF COAST STATES ENSURING CAA WILL BE
DELIVERED DEEP INTO THE SE STATES THROUGH THE PERIOD.
MOSTLY CLEAR/MOSTLY SUNNY SKIES EXPECTED MONDAY NIGHT THROUGH
THURSDAY. LOWS GENERALLY AT OR SLIGHTLY BELOW 32. HIGHS 50-55.
THESE READINGS WILL REMAIN AROUND 15 DEGREES BELOW NORMAL.
&&
.AVIATION /18Z THURSDAY THROUGH TUESDAY/...
AS OF 115 PM THURSDAY...
24-HR TAF PERIOD:
ASIDE FROM A BRIEF PERIOD OF MVFR CONDITIONS ASSOCIATED WITH SNOW
SHOWERS AT THE RWI TERMINAL BETWEEN 16-19Z...VFR CONDITIONS WILL
RULE THROUGH THE TAF PERIOD. NORTHWEST WINDS WILL BECOME SUSTAINED
AT 10-15 KT WITH GUSTS UP TO 20-25 KT LATER THIS AFTERNOON... BEFORE
DECREASING TO 5-10 KT AROUND SUNSET THIS EVENING. WINDS WILL BECOME
LIGHT/VARIABLE TONIGHT AND REMAIN LIGHT/VARIABLE THROUGH 15-18Z
FRIDAY.
LOOKING AHEAD:
VFR CONDITIONS WILL PREVAIL FRIDAY THROUGH EARLY FRIDAY NIGHT...WITH
AN INCREASING CHANCE FOR MVFR CEILINGS BETWEEN MIDNIGHT AND SUNRISE
SATURDAY MORNING IN ASSOC/W AN INCREASINGLY MOIST SOUTHWESTERLY
LOW-LEVEL RETURN FLOW FROM THE GULF OF MEXICO. WIDESPREAD ADVERSE
AVIATION CONDITIONS ARE EXPECTED OVER THE WEEKEND (PRIMARILY LATE
SAT NIGHT THROUGH SUNDAY) AS A DEVELOPING LOW PRESSURE SYSTEM OVER
THE DEEP SOUTH TRACKS NORTHEAST INTO THE CAROLINAS AND MID-ATLANTIC.
AT THIS TIME...THE BEST CHANCE FOR RAIN AND IFR CONDITIONS IS
EXPECTED BETWEEN 12Z SUN AND 06Z MON. -VINCENT
&&
.FIRE WEATHER...
THE SPECIAL WEATHER STATEMENT FOR INCREASED FIRE DANGER WILL BE
ALLOWED TO REMAIN IN EFFECT THROUGH 00Z THIS EVENING IN ASSOC/W RH
VALUES AT OR BELOW 25% AND NW WINDS SUSTAINED AT 10-15 MPH WITH
GUSTS UP TO 25 MPH DURING THE MID/LATE AFTERNOON HOURS. -VINCENT
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...VINCENT
NEAR TERM...VINCENT/HARTFIELD
SHORT TERM...BADGETT
LONG TERM...BADGETT
AVIATION...VINCENT
FIRE WEATHER...VINCENT
AREA FORECAST DISCUSSION
NWS RALEIGH NC
114 PM EDT THU MAR 21 2013
.SYNOPSIS...
COLD HIGH PRESSURE WILL BUILD INTO THE REGION FROM THE NORTHWEST
THROUGH FRIDAY. A COMPLEX LOW PRESSURE SYSTEM WILL DEVELOP OVER THE
DEEP SOUTH ON SATURDAY...THEN TRACK NORTHEAST INTO THE CAROLINAS AND
MID ATLANTIC ON SUNDAY.
&&
.NEAR TERM /THROUGH FRIDAY NIGHT/...
AS OF 1030 AM THURSDAY...
SHORTWAVE ENERGY ROUNDING THE BASE OF AN UNSEASONABLY COLD CYCLONIC
GYRE (CENTERED OVER NEW ENGLAND AND THE LOWER GREAT LAKES) WILL
TRACK EAST FROM THE VIRGINIAS INTO THE DELMARVA THROUGH 18Z THIS
AFTERNOON. DESPITE LOW-LEVEL COLD ADVECTION AND A DRY BOUNDARY
LAYER...DPVA ASSOCIATED WITH THE AFOREMENTIONED SHORTWAVE ENERGY AND
WEAK MID-LEVEL FRONTOGENESIS HAS CONTRIBUTED TO THE DEVELOPMENT OF
LIGHT BANDED PRECIPITATION OVER SOUTHERN VA NEAR THE NC/VA BORDER IN
VICINITY OF THE I-85 CORRIDOR. RAP PROXIMITY SOUNDINGS INDICATE THAT
THERMAL PROFILES ARE SUPPORTIVE OF SNOW WHERE SATURATION EXTENDS
INTO THE ICE NUCLEATION ZONE...IN AGREEMENT WITH THE LATEST
OBSERVATIONAL DATA ACROSS SOUTHERN VA WHERE SEVERAL SITES HAVE
REPORTED LIGHT SNOW. ALTHOUGH THE BOUNDARY LAYER IS SLIGHTLY WARMER
IN THE NORTHERN PIEDMONT AND NE COASTAL PLAIN IN COMPARISON TO
SOUTHERN VA...WETBULB PROFILES REMAIN SUPPORTIVE OF A CHANCE FOR
SNOW WHERE PRECIP IS OF SUFFICIENT INTENSITY TO MOISTEN THE
LOWER-LEVELS AND ONGOING COLD ADVECTION WILL SERVE TO LIMIT THE
EFFECTS OF DIURNAL HEATING. WITH THE ABOVE IN MIND...EXPECT A CHANCE
OF SNOW OR RAIN/SNOW SHOWERS ACROSS THE NORTHERN PIEDMONT AND
NORTHEAST COASTAL PLAIN THROUGH 16-18Z THIS AFTERNOON. GIVEN STRONG
CAA/DEEP MIXING (UP TO 800-850 MB) IN THE PRESENCE OF AN ATYPICALLY
COLD LOW-LEVEL AIRMASS CHARACTERIZED BY H85 TEMPS RANGING FROM -7C
(SOUTH) TO -12C (NORTH)...EXPECT HIGHS TODAY TO RANGE FROM THE UPPER
30S /NEAR 40F/ NEAR THE VA BORDER TO THE MID/UPPER 40S NEAR THE SC
BORDER. -VINCENT
FOR TONIGHT: WINDS SHOULD DIMINISH QUICKLY BY EARLY EVENING WITH THE
LOOSENING MSLP GRADIENT AS THE SURFACE RIDGE EXPANDS OVER THE
CAROLINAS FROM THE NW. WE MAY SEE A FEW HIGH CLOUDS IN THE LEE OFF
THE SRN APPALACHIANS OVER THE SWRN PIEDMONT TOWARD MORNING WITH THE
400 MB FRONTAL ZONE SHIFTING BACK TO THE NNE INTO NC. OTHERWISE...
EXPECT CLEAR SKIES. GUIDANCE TRENDS AND THICKNESSES SUPPORT LOWS OF
22-27. FORECAST LOWS AT GSO (24) AND RDU (24) ARE WITHIN A COUPLE
DEGREES OF RECORD LOWS FOR MARCH 22 (BOTH RECORDS ARE 22 LAST SET IN
1986). FAY`S LOW (FORECAST OF 26 AND RECORD LOW OF 22 SET IN 1956)
APPEARS SAFE.
FOR FRIDAY/FRIDAY NIGHT: A PORTION OF THE SURFACE RIDGE EXTENDING
THROUGH THE CAROLINAS FROM THE NW BREAKS OFF OVER THE SOUTHEAST
COAST... RESULTING IN NW AND WNW WINDS SWINGING AROUND TO
SOUTHWESTERLY BUT REMAINING LIGHT. THE FRONTAL ZONE LOCATED ALONG FL
AND THE NORTHERN GULF TODAY WILL START TO HEAD BACK NORTH AND NNE AS
A WARM FRONT... DRIVEN BY AN APPROACHING TROUGH AND FALLING HEIGHTS
OVER THE DESERT SOUTHWEST AND LOWERING SURFACE PRESSURES OVER TX.
EXPECT PLENTY OF SUNSHINE THROUGH MUCH OF FRIDAY WITH DEEP DRY AND
STABLE AIR IN PLACE... THEN INCREASING ISENTROPIC UPGLIDE FROM THE
SW SHOULD RESULT IN QUICKLY INCREASING AND THICKENING CLOUDS FRIDAY
EVENING AND NIGHT AS HIGHER PRECIP WATER (150% OF NORMAL) SPREADS
INTO NC FROM THE SSW. OVERALL FORCING FOR ASCENT REMAINS MUTED...
AND THE COLUMN DOES NOT COMPLETELY SATURATE ACCORDING TO GFS/NAM
FORECAST SOUNDINGS... BUT THE GFS DEPICTS FAIRLY STRONG MOIST
UPGLIDE AT 295-310K BY 12Z SATURDAY SUCH IT PRODUCES ONE TO TWO
TENTHS OF AN INCH OF PRECIP OVER THE SRN CWA. EVEN THE NAM HAS A 30
KT SWRLY LOW LEVEL JET NOSING INTO THE NORTHWARD-RETREATING WARM
FRONT AS IT HEADS INTO SRN NC. WILL BRING IN A SMALL CHANCE OF RAIN
OVER THE SW AND FAR SRN CWA LATE FRIDAY NIGHT. THE LOW LEVEL TEMP
PROFILE SUPPORTS AN UPWARD NUDGE TO HIGHS... TO 52-55 DEGREES. THIS
IS ON THE COOL SIDE OF STATISTICAL GUIDANCE AND MAY STILL BE TOO
COOL IF GUIDANCE TRENDS ARE CORRECT. LOWS 32-39. -GIH
&&
.SHORT TERM /SATURDAY THROUGH SUNDAY/...
AS OF 1230 PM THURSDAY...
A COLD RAIN EXPECTED LATE SATURDAY THROUGH SUNDAY...
STRONG HIGH LATITUDE BLOCKING DOWNSTREAM AND THE STRONGLY NEGATIVE
PHASE OF BOTH THE ARCTIC OSCILLATION (AO) AND NORTH ATLANTIC
OSCILLATION (NAO) ARE FORECAST TO CONTINUE THROUGH EARLY NEXT
WEEK... KEEPING TEMPERATURES MUCH BELOW NORMAL (LIKELY 15-20
DEGREES) THROUGH SUNDAY. SEVERAL MID/UPPER DISTURBANCES WILL MOVE
EAST OUT OF THE ROCKIES IN SUPPRESSED FASHION ACROSS THE DEEP
SOUTH... WITH THE POLAR FRONT POSITIONED WELL SOUTH (ALONG THE GULF
OF MEXICO).
THE MOST SUBSTANTIAL SHORTWAVE IS FORECAST TO EMERGE ACROSS THE
SOUTHERN PLAINS SUNDAY AND TRACK GENERALLY EAST ACROSS THE TENNESSEE
VALLEY AND CENTRAL APPALACHIANS LATE IN THE WEEKEND INTO EARLY
MONDAY. THIS SHOULD LEAD TO A "MILLER-B" SURFACE LOW PRESSURE
EVOLUTION AND HYBRID COLD AIR DAMMING EVENT SUNDAY INTO EARLY
MONDAY. AHEAD OF THIS WAVE... STRENGTHENING SSW FLOW AND WARM
ADVECTION BETWEEN H925 AND H7 SHOULD SPREAD SOME LIGHT PRECIP ACROSS
THE SOUTHEAST UNITED STATES AS EARLY AS SATURDAY AS THE 850MB FRONT
LIFTS NORTH ACROSS AL/GA/SC. HOWEVER... MODELS CONTINUE TO DISAGREE
ON THE NORTHWARD EXTENT OF MEASURABLE PRECIPITATION.
THE LATEST NAM AND GFS RUNS CONTINUE TO BRING SOME LIGHT MEASURABLE
RAIN INTO OUR WESTERN AND SOUTHERN COUNTIES LATE FRIDAY NIGHT AND
EARLY SATURDAY. THIS WOULD BE ASSOCIATED WITH A LEAD DISTURBANCE AND
PARTIAL THICKNESSES BECOME WARM ENOUGH FOR ALL RAIN. THE EC HAS NOT
BEEN AS AGGRESSIVE WITH THE LIGHT MEASURABLE RAIN WITH THE LEAD WAVE
THIS FAR NORTHEAST... BUT GIVEN THAT THE NAM AND GFS HAVE HAD 4
CONSECUTIVE RUNS WITH THE SAME FORECAST OF LIGHT QPF... WE WILL KEEP
LOW END CHANCES FOR THE SOUTHERN ZONES (ALBEMARLE TO FAYETTEVILLE)
LATE FRIDAY NIGHT INTO MID-DAY SATURDAY. OTHERWISE... GIVEN THE
EXTENT OF THE DRYNESS THE ANTECEDENT AIR MASS IS EXPECTED TO BE...
PREFER TO STICK WITH THE DRY EC OVER THE NORTHERN COUNTIES THROUGH
SATURDAY. HIGHS SATURDAY SHOULD BE FAIRLY UNIFORM ACROSS THE
REGION... WITH THE POSSIBLE LIGHT RAIN EARLY IN THE SOUTH... HIGHS
SHOULD BE ONLY IN THE 50-55 RANGE MOST AREAS. IF SOME LIGHT RAIN IS
MEASURED... TEMPS SHOULD BE EVEN COOLER.
FOR SATURDAY NIGHT AND SUNDAY... EXPECT RAIN TO OVERSPREAD/DEVELOP
NORTHWARD ACROSS OUR REGION WITH THE APPROACH OF THE STRONG
MID/UPPER LEVEL WAVE FROM THE WEST. THE GFS AND NAM CONTINUE TO
DRIVE A STRENGTHENING SURFACE WAVE NE THROUGH THE TENNESSEE VALLEY
INTO THE LOWER OHIO VALLEY SAT NIGHT AND SUNDAY... WITH SECONDARY
BECOMING PRIMARY LOW PRESSURE DEVELOPMENT OFF THE SC COAST SUNDAY.
WITH THE LATTER EXPECTED TO TRACK ALONG THE COAST OF NC LATE SUNDAY
INTO SUNDAY NIGHT... HYBRID CAD WILL BECOME ENTRENCHED OVER CENTRAL
NC THROUGHOUT THE EVENT.
SENSIBLE WEATHER WILL INCLUDE... RAIN DEVELOPING SATURDAY NIGHT WITH
LOWS OF 35-40. RAIN TAPERING TO AREAS OF DRIZZLE LATE SUNDAY. COLD
WITH HIGHS IN THE 40S EXCEPT UPPER 30S NW. QPF ON THE ORDER OF 0.50
TO 0.75 EXPECTED (MAINLY BETWEEN 06Z AND 15Z SUNDAY... TAPERING TO
LIGHT 0.10 AMOUNTS SUNDAY AFTERNOON). STORM TOTALS SHOULD REMAIN
BELOW 1 INCH. STRONG CAA WILL FOLLOW THE STORM INTO NC FROM THE NW
BEGINNING LATE SUNDAY NIGHT. LOWS 35-40 (CLEARING LATE SUNDAY
NIGHT).
&&
.LONG TERM /MONDAY THROUGH THURSDAY/...
AS OF 1230 PM THURSDAY...
STRONG CAA ON MONDAY IN THE REAR OF THE DEPARTING STORM MOVING OUT
INTO THE ATLANTIC WILL KEEP HIGHS ONLY IN THE 40S TO LOWER 50S
(15-20 DEGREES BELOW NORMAL). NW WINDS 15-20 MPH WILL GUST TO 30
MPH. SOME VERY LIGHT SNOW SHOWERS MAY OCCUR ESPECIALLY IN AREAS N-E
OF RALEIGH (NORTHERN COASTAL PLAIN)... BUT NOTHING SIGNIFICANT
EXPECTED. OTHERWISE... PARTLY SUNNY AND WINDY.
CLEAR AND COLD MONDAY NIGHT SHOULD YIELD LOWS IN THE UPPER 20S AND
LOWER 30S (10-15 DEGREES BELOW NORMAL).
TUESDAY THROUGH THURSDAY... A MOSTLY DRY AND CHILLY PATTERN SHOULD
CONTINUE WITH THE DEEP TROUGH EXPECTED TO RELAX A BIT MID-LATE WEEK.
HOWEVER... A STRONG SURFACE HIGH SHOULD EXTEND FROM THE NORTHERN
PLAINS DEEP INTO THE GULF COAST STATES ENSURING CAA WILL BE
DELIVERED DEEP INTO THE SE STATES THROUGH THE PERIOD.
MOSTLY CLEAR/MOSTLY SUNNY SKIES EXPECTED MONDAY NIGHT THROUGH
THURSDAY. LOWS GENERALLY AT OR SLIGHTLY BELOW 32. HIGHS 50-55. THESE
READINGS WILL REMAIN AROUND 15 DEGREES BELOW NORMAL.
&&
.AVIATION /18Z THURSDAY THROUGH TUESDAY/...
AS OF 115 PM THURSDAY...
24-HR TAF PERIOD:
ASIDE FROM A BRIEF PERIOD OF MVFR CONDITIONS ASSOCIATED WITH SNOW
SHOWERS AT THE RWI TERMINAL BETWEEN 16-19Z...VFR CONDITIONS WILL
RULE THROUGH THE TAF PERIOD. NORTHWEST WINDS WILL BECOME SUSTAINED
AT 10-15 KT WITH GUSTS UP TO 20-25 KT LATER THIS AFTERNOON... BEFORE
DECREASING TO 5-10 KT AROUND SUNSET THIS EVENING. WINDS WILL BECOME
LIGHT/VARIABLE TONIGHT AND REMAIN LIGHT/VARIABLE THROUGH 15-18Z
FRIDAY.
LOOKING AHEAD:
VFR CONDITIONS WILL PREVAIL FRIDAY THROUGH EARLY FRIDAY NIGHT...WITH
AN INCREASING CHANCE FOR MVFR CEILINGS BETWEEN MIDNIGHT AND SUNRISE
SATURDAY MORNING IN ASSOC/W AN INCREASINGLY MOIST SOUTHWESTERLY
LOW-LEVEL RETURN FLOW FROM THE GULF OF MEXICO. WIDESPREAD ADVERSE
AVIATION CONDITIONS ARE EXPECTED OVER THE WEEKEND (PRIMARILY LATE
SAT NIGHT THROUGH SUNDAY) AS A DEVELOPING LOW PRESSURE SYSTEM OVER
THE DEEP SOUTH TRACKS NORTHEAST INTO THE CAROLINAS AND MID-ATLANTIC.
AT THIS TIME...THE BEST CHANCE FOR RAIN AND IFR CONDITIONS IS
EXPECTED BETWEEN 12Z SUN AND 06Z MON. -VINCENT
&&
.FIRE WEATHER...
THE SPECIAL WEATHER STATEMENT FOR INCREASED FIRE DANGER WILL BE
ALLOWED TO REMAIN IN EFFECT THROUGH 00Z THIS EVENING IN ASSOC/W RH
VALUES AT OR BELOW 25% AND NW WINDS SUSTAINED AT 10-15 MPH WITH
GUSTS UP TO 25 MPH DURING THE MID/LATE AFTERNOON HOURS. -VINCENT
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...VINCENT
NEAR TERM...VINCENT/HARTFIELD
SHORT TERM...BADGETT
LONG TERM...BADGETT
AVIATION...VINCENT
FIRE WEATHER...VINCENT
AREA FORECAST DISCUSSION
NWS RALEIGH NC
1233 PM EDT THU MAR 21 2013
.SYNOPSIS...
COLD HIGH PRESSURE WILL BUILD INTO THE REGION FROM THE NORTHWEST
THROUGH FRIDAY. A COMPLEX LOW PRESSURE SYSTEM WILL DEVELOP OVER THE
DEEP SOUTH ON SATURDAY...THEN TRACK NORTHEAST INTO THE CAROLINAS AND
MID ATLANTIC ON SUNDAY.
&&
.NEAR TERM /THROUGH FRIDAY NIGHT/...
AS OF 1030 AM THURSDAY...
SHORTWAVE ENERGY ROUNDING THE BASE OF AN UNSEASONABLY COLD CYCLONIC
GYRE (CENTERED OVER NEW ENGLAND AND THE LOWER GREAT LAKES) WILL
TRACK EAST FROM THE VIRGINIAS INTO THE DELMARVA THROUGH 18Z THIS
AFTERNOON. DESPITE LOW-LEVEL COLD ADVECTION AND A DRY BOUNDARY
LAYER...DPVA ASSOCIATED WITH THE AFOREMENTIONED SHORTWAVE ENERGY AND
WEAK MID-LEVEL FRONTOGENESIS HAS CONTRIBUTED TO THE DEVELOPMENT OF
LIGHT BANDED PRECIPITATION OVER SOUTHERN VA NEAR THE NC/VA BORDER IN
VICINITY OF THE I-85 CORRIDOR. RAP PROXIMITY SOUNDINGS INDICATE THAT
THERMAL PROFILES ARE SUPPORTIVE OF SNOW WHERE SATURATION EXTENDS
INTO THE ICE NUCLEATION ZONE...IN AGREEMENT WITH THE LATEST
OBSERVATIONAL DATA ACROSS SOUTHERN VA WHERE SEVERAL SITES HAVE
REPORTED LIGHT SNOW. ALTHOUGH THE BOUNDARY LAYER IS SLIGHTLY WARMER
IN THE NORTHERN PIEDMONT AND NE COASTAL PLAIN IN COMPARISON TO
SOUTHERN VA...WETBULB PROFILES REMAIN SUPPORTIVE OF A CHANCE FOR
SNOW WHERE PRECIP IS OF SUFFICIENT INTENSITY TO MOISTEN THE
LOWER-LEVELS AND ONGOING COLD ADVECTION WILL SERVE TO LIMIT THE
EFFECTS OF DIURNAL HEATING. WITH THE ABOVE IN MIND...EXPECT A CHANCE
OF SNOW OR RAIN/SNOW SHOWERS ACROSS THE NORTHERN PIEDMONT AND
NORTHEAST COASTAL PLAIN THROUGH 16-18Z THIS AFTERNOON. GIVEN STRONG
CAA/DEEP MIXING (UP TO 800-850 MB) IN THE PRESENCE OF AN ATYPICALLY
COLD LOW-LEVEL AIRMASS CHARACTERIZED BY H85 TEMPS RANGING FROM -7C
(SOUTH) TO -12C (NORTH)...EXPECT HIGHS TODAY TO RANGE FROM THE UPPER
30S /NEAR 40F/ NEAR THE VA BORDER TO THE MID/UPPER 40S NEAR THE SC
BORDER. -VINCENT
FOR TONIGHT: WINDS SHOULD DIMINISH QUICKLY BY EARLY EVENING WITH THE
LOOSENING MSLP GRADIENT AS THE SURFACE RIDGE EXPANDS OVER THE
CAROLINAS FROM THE NW. WE MAY SEE A FEW HIGH CLOUDS IN THE LEE OFF
THE SRN APPALACHIANS OVER THE SWRN PIEDMONT TOWARD MORNING WITH THE
400 MB FRONTAL ZONE SHIFTING BACK TO THE NNE INTO NC. OTHERWISE...
EXPECT CLEAR SKIES. GUIDANCE TRENDS AND THICKNESSES SUPPORT LOWS OF
22-27. FORECAST LOWS AT GSO (24) AND RDU (24) ARE WITHIN A COUPLE
DEGREES OF RECORD LOWS FOR MARCH 22 (BOTH RECORDS ARE 22 LAST SET IN
1986). FAY`S LOW (FORECAST OF 26 AND RECORD LOW OF 22 SET IN 1956)
APPEARS SAFE.
FOR FRIDAY/FRIDAY NIGHT: A PORTION OF THE SURFACE RIDGE EXTENDING
THROUGH THE CAROLINAS FROM THE NW BREAKS OFF OVER THE SOUTHEAST
COAST... RESULTING IN NW AND WNW WINDS SWINGING AROUND TO
SOUTHWESTERLY BUT REMAINING LIGHT. THE FRONTAL ZONE LOCATED ALONG FL
AND THE NORTHERN GULF TODAY WILL START TO HEAD BACK NORTH AND NNE AS
A WARM FRONT... DRIVEN BY AN APPROACHING TROUGH AND FALLING HEIGHTS
OVER THE DESERT SOUTHWEST AND LOWERING SURFACE PRESSURES OVER TX.
EXPECT PLENTY OF SUNSHINE THROUGH MUCH OF FRIDAY WITH DEEP DRY AND
STABLE AIR IN PLACE... THEN INCREASING ISENTROPIC UPGLIDE FROM THE
SW SHOULD RESULT IN QUICKLY INCREASING AND THICKENING CLOUDS FRIDAY
EVENING AND NIGHT AS HIGHER PRECIP WATER (150% OF NORMAL) SPREADS
INTO NC FROM THE SSW. OVERALL FORCING FOR ASCENT REMAINS MUTED...
AND THE COLUMN DOES NOT COMPLETELY SATURATE ACCORDING TO GFS/NAM
FORECAST SOUNDINGS... BUT THE GFS DEPICTS FAIRLY STRONG MOIST
UPGLIDE AT 295-310K BY 12Z SATURDAY SUCH IT PRODUCES ONE TO TWO
TENTHS OF AN INCH OF PRECIP OVER THE SRN CWA. EVEN THE NAM HAS A 30
KT SWRLY LOW LEVEL JET NOSING INTO THE NORTHWARD-RETREATING WARM
FRONT AS IT HEADS INTO SRN NC. WILL BRING IN A SMALL CHANCE OF RAIN
OVER THE SW AND FAR SRN CWA LATE FRIDAY NIGHT. THE LOW LEVEL TEMP
PROFILE SUPPORTS AN UPWARD NUDGE TO HIGHS... TO 52-55 DEGREES. THIS
IS ON THE COOL SIDE OF STATISTICAL GUIDANCE AND MAY STILL BE TOO
COOL IF GUIDANCE TRENDS ARE CORRECT. LOWS 32-39. -GIH
&&
.SHORT TERM /SATURDAY THROUGH SUNDAY/...
AS OF 1230 PM THURSDAY...
A COLD RAIN EXPECTED LATE SATURDAY THROUGH SUNDAY...
STRONG HIGH LATITUDE BLOCKING DOWNSTREAM AND THE STRONGLY NEGATIVE
PHASE OF BOTH THE ARCTIC OSCILLATION (AO) AND NORTH ATLANTIC
OSCILLATION (NAO) ARE FORECAST TO CONTINUE THROUGH EARLY NEXT
WEEK... KEEPING TEMPERATURES MUCH BELOW NORMAL (LIKELY 15-20
DEGREES) THROUGH SUNDAY. SEVERAL MID/UPPER DISTURBANCES WILL MOVE
EAST OUT OF THE ROCKIES IN SUPPRESSED FASHION ACROSS THE DEEP SOUTH...
WITH THE POLAR FRONT POSITIONED WELL SOUTH (ALONG THE GULF OF
MEXICO).
THE MOST SUBSTANTIAL SHORTWAVE IS FORECAST TO EMERGE ACROSS THE
SOUTHERN PLAINS SUNDAY AND TRACK GENERALLY EAST ACROSS THE TENNESSEE
VALLEY AND CENTRAL APPALACHIANS LATE IN THE WEEKEND INTO EARLY
MONDAY. THIS SHOULD LEAD TO A "MILLER-B" SURFACE LOW PRESSURE
EVOLUTION AND HYBRID COLD AIR DAMMING EVENT SUNDAY INTO EARLY
MONDAY. AHEAD OF THIS WAVE... STRENGTHENING SSW FLOW AND WARM
ADVECTION BETWEEN H925 AND H7 SHOULD SPREAD SOME LIGHT PRECIP ACROSS
THE SOUTHEAST UNITED STATES AS EARLY AS SATURDAY AS THE 850MB FRONT
LIFTS NORTH ACROSS AL/GA/SC. HOWEVER... MODELS CONTINUE TO DISAGREE
ON THE NORTHWARD EXTENT OF MEASURABLE PRECIPITATION.
THE LATEST NAM AND GFS RUNS CONTINUE TO BRING SOME LIGHT MEASURABLE
RAIN INTO OUR WESTERN AND SOUTHERN COUNTIES LATE FRIDAY NIGHT AND
EARLY SATURDAY. THIS WOULD BE ASSOCIATED WITH A LEAD DISTURBANCE AND
PARTIAL THICKNESSES BECOME WARM ENOUGH FOR ALL RAIN. THE EC HAS NOT
BEEN AS AGGRESSIVE WITH THE LIGHT MEASURABLE RAIN WITH THE LEAD WAVE
THIS FAR NORTHEAST... BUT GIVEN THAT THE NAM AND GFS HAVE HAD 4
CONSECUTIVE RUNS WITH THE SAME FORECAST OF LIGHT QPF... WE WILL KEEP
LOW END CHANCES FOR THE SOUTHERN ZONES (ALBEMARLE TO FAYETTEVILLE)
LATE FRIDAY NIGHT INTO MID-DAY SATURDAY. OTHERWISE... GIVEN THE
EXTENT OF THE DRYNESS THE ANTECEDENT AIR MASS IS EXPECTED TO BE...
PREFER TO STICK WITH THE DRY EC OVER THE NORTHERN COUNTIES THROUGH
SATURDAY. HIGHS SATURDAY SHOULD BE FAIRLY UNIFORM ACROSS THE
REGION... WITH THE POSSIBLE LIGHT RAIN EARLY IN THE SOUTH... HIGHS
SHOULD BE ONLY IN THE 50-55 RANGE MOST AREAS. IF SOME LIGHT RAIN IS
MEASURED... TEMPS SHOULD BE EVEN COOLER.
FOR SATURDAY NIGHT AND SUNDAY... EXPECT RAIN TO OVERSPREAD/DEVELOP
NORTHWARD ACROSS OUR REGION WITH THE APPROACH OF THE STRONG
MID/UPPER LEVEL WAVE FROM THE WEST. THE GFS AND NAM CONTINUE TO
DRIVE A STRENGTHENING SURFACE WAVE NE THROUGH THE TENNESSEE VALLEY
INTO THE LOWER OHIO VALLEY SAT NIGHT AND SUNDAY... WITH SECONDARY
BECOMING PRIMARY LOW PRESSURE DEVELOPMENT OFF THE SC COAST SUNDAY.
WITH THE LATTER EXPECTED TO TRACK ALONG THE COAST OF NC LATE SUNDAY
INTO SUNDAY NIGHT... HYBRID CAD WILL BECOME ENTRENCHED OVER CENTRAL
NC THROUGHOUT THE EVENT.
SENSIBLE WEATHER WILL INCLUDE... RAIN DEVELOPING SATURDAY NIGHT WITH
LOWS OF 35-40. RAIN TAPERING TO AREAS OF DRIZZLE LATE SUNDAY. COLD
WITH HIGHS IN THE 40S EXCEPT UPPER 30S NW. QPF ON THE ORDER OF 0.50
TO 0.75 EXPECTED (MAINLY BETWEEN 06Z AND 15Z SUNDAY... TAPERING TO
LIGHT 0.10 AMOUNTS SUNDAY AFTERNOON). STORM TOTALS SHOULD REMAIN
BELOW 1 INCH. STRONG CAA WILL FOLLOW THE STORM INTO NC FROM THE NW
BEGINNING LATE SUNDAY NIGHT. LOWS 35-40 (CLEARING LATE SUNDAY
NIGHT).
&&
.LONG TERM /MONDAY THROUGH THURSDAY/...
AS OF 1230 PM THURSDAY...
STRONG CAA ON MONDAY IN THE REAR OF THE DEPARTING STORM MOVING OUT
INTO THE ATLANTIC WILL KEEP HIGHS ONLY IN THE 40S TO LOWER 50S
(15-20 DEGREES BELOW NORMAL). NW WINDS 15-20 MPH WILL GUST TO 30
MPH. SOME VERY LIGHT SNOW SHOWERS MAY OCCUR ESPECIALLY IN AREAS N-E
OF RALEIGH (NORTHERN COASTAL PLAIN)... BUT NOTHING SIGNIFICANT
EXPECTED. OTHERWISE... PARTLY SUNNY AND WINDY.
CLEAR AND COLD MONDAY NIGHT SHOULD YIELD LOWS IN THE UPPER 20S AND
LOWER 30S (10-15 DEGREES BELOW NORMAL).
TUESDAY THROUGH THURSDAY... A MOSTLY DRY AND CHILLY PATTERN SHOULD
CONTINUE WITH THE DEEP TROUGH EXPECTED TO RELAX A BIT MID-LATE WEEK.
HOWEVER... A STRONG SURFACE HIGH SHOULD EXTEND FROM THE NORTHERN
PLAINS DEEP INTO THE GULF COAST STATES ENSURING CAA WILL BE
DELIVERED DEEP INTO THE SE STATES THROUGH THE PERIOD.
MOSTLY CLEAR/MOSTLY SUNNY SKIES EXPECTED MONDAY NIGHT THROUGH
THURSDAY. LOWS GENERALLY AT OR SLIGHTLY BELOW 32. HIGHS 50-55. THESE
READINGS WILL REMAIN AROUND 15 DEGREES BELOW NORMAL.
&&
.AVIATION /12Z THURSDAY THROUGH MONDAY/...
AS OF 740 AM THURSDAY...
VFR CONDITIONS WILL DOMINATE THROUGH TONIGHT.
A COLD FRONT WILL SHIFT OFF THE NC COAST THIS MORNING. BEHIND THE
FRONT... WINDS FROM THE NW (290-320 DEGREES) AROUND 15 KTS WILL GUST
TO 25-30 KTS THROUGH THIS AFTERNOON... WITH SCT-BKN CLOUDS BASED AT
OR ABOVE 5 THOUSAND FT AGL. WINDS WILL DISSIPATE AFTER 22Z WITH
SKIES BECOMING UNLIMITED AS CHILLY HIGH PRESSURE BUILDS IN.
LOOKING BEYOND 12Z FRIDAY... VFR CONDITIONS WILL HOLD THROUGH FRIDAY
NIGHT. THERE IS A GOOD CHANCE OF MVFR CIGS SATURDAY AS A COMPLEX
STORM SYSTEM MOVES INTO THE REGION FROM THE WSW. THESE ARE LIKELY TO
WORSEN TO IFR SATURDAY NIGHT AND PERSIST THROUGH SUNDAY NIGHT. SMALL
IMPROVEMENT TO MVFR CIGS IS POSSIBLE MONDAY AS THE STORM SLOWLY
DEPARTS. -GIH
&&
.FIRE WEATHER...
FOLLOWING YESTERDAY`S COORDINATION WITH THE NCFS... WILL CONTINUE
WITH A STATEMENT FOR INCREASED FIRE DANGER FOR TODAY. DESPITE THE
CHILLY TEMPS TODAY... WITH DEW POINTS DROPPING INTO THE LOW TEENS
AND SINGLE DIGITS... THE RELATIVE HUMIDITY IS EXPECTED TO BOTTOM OUT
AT 20-25 PERCENT... AND SUSTAINED WINDS OF 15-20 MPH ARE EXPECTED TO
GUST TO 25-30 MPH. SCANT RAINFALL OF LATE AND FAIRLY LOW FUEL
MOISTURE WILL EXACERBATE THE THREAT OF ADVERSE FIRE BEHAVIOR. -GIH
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...VINCENT
NEAR TERM...VINCENT/HARTFIELD
SHORT TERM...BADGETT
LONG TERM...BADGETT
AVIATION...HARTFIELD
FIRE WEATHER...HARTFIELD
AREA FORECAST DISCUSSION
NWS SIOUX FALLS SD
1228 PM CDT THU MAR 21 2013
.UPDATE...
ISSUED AT 1013 AM CDT THU MAR 21 2013
VIRGA ECHOES STILL PREVAILING ACROSS THE SOUTHWEST CWA...HOWEVER
WITH WINNER REPORTING LIGHT SNOW WITH 4SM VSBY LAST HOUR...OPTED
TO ADD A MENTION OF FLURRIES AS WEAKENING SHORT WAVE LINGERS
THROUGH REMAINDER OF MORNING AND EARLY AFTERNOON. ALSO DELAYED
ONSET OF PRECIP ACROSS THE WEST WITH SECONDARY SHORT WAVE TO ENTER
AFTER 00Z THIS EVENING. 12Z NAM AND LATEST HRRR SHOWING DRY
CONDITIONS UNTIL CLOSER TO 03Z IN THE WEST AND SOUNDINGS STILL
SHOWING DRY LAYER THAT WILL TAKE TIME TO SATURATE. OTHERWISE
FORECAST LOOKS ON TRACK.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 342 AM CDT THU MAR 21 2013
CURRENTLY...VIRGA ECHOES ARE EVIDENT RIGHT ON THE SOUTHWEST CORNER
OF OUR FORECAST AREA. THIS ACTIVITY IS ASSOCIATED WITH A WEAK MID
LEVEL SHORT WAVE SITUATED IN WESTERN SD AND WESTERN NE...AND WILL
DRIFT SOUTHEASTWARD EARLY THIS MORNING GENERALLY AWAY FROM OUR
AREA. ISENTROPIC LIFT IS PRETTY STRONG WITH THIS WAVE TO THE
SOUTHWEST...COUPLED WITH SOME THETA E ADVECTION. BUT LOW LEVELS
ARE MOISTURE STARVED. THEREFORE DID NOT PUT ANY POPS IN GREGORY
COUNTY FOR EARLY TODAY. OTHERWISE THE REST OF THE DAY IS PRETTY
MUCH WHAT YOU SEE IS WHAT YOU GET. MOST OF THE CLOUDINESS WILL
REMAIN BOTTLED UP IN OUR WESTERN ZONES...WITH CLEARING SKIES
HEADING EASTWARD FROM THERE. IT WILL BE ANOTHER CHILLY DAY WITH
TEMPERATURES WELL BELOW NORMAL...WITH A COOL EASTERLY FETCH OF AIR
NOT HELPING THINGS ANY. MODELS HAVE GREATLY SLOWED THE ONSLAUGHT
OF PRECIPITATION POTENTIAL. WITH SOME MISGIVINGS...KEPT LOW POPS
GOING IN OUR EXTREME WESTERN ZONES NEAR CHAMBERLAIN...BUT WOULD
NOT BE SURPRISED IF NOTHING HAPPENED THERE BEFORE 00Z FRIDAY. IF
LIGHT PRECIPITATION WOULD HAPPEN TO OCCUR...KEPT THE TYPE AS LIGHT
SNOW EVEN THOUGH SURFACE TEMPERATURES LATE TODAY ARE IN THE UPPER
30S ACROSS THOSE LOCATIONS. AIR MASS IS SUB ZERO AT 850MB AND
SURFACE DEW POINTS ARE NOT REAL HIGH ALLOWING FOR SOME WET BULBING
AFFECT.
TONIGHT...THE CRUX OF A SECOND SHORT WAVE MOVES EASTWARD INTO OUR
FORECAST AREA...MOVING ALONG THE SOUTHERN END OF A LARGE UPPER
TROUGH SITUATED THROUGHOUT WESTERN CANADA AND THE NORTHWEST UNITED
STATES. THE 00Z NAM/GFS/UKMET/GEM ARE ALL IN EXCELLENT AGREEMENT
WITH THE TIMING OF THE SHORT WAVE AND THE SUBSEQUENT SATURATION OF
THE PROFILE. HOWEVER...ISENTROPIC LIFT IS DECIDEDLY WEAKER IN THE
MID LEVELS WHEN COMPARED TO YESTERDAYS MODELS FOR OUR FORECAST AREA.
FURTHERMORE...THE 00Z ECMWF HAS JUST COME IN KEEPING THE
PRECIPITATION POTENTIAL JUST WEST OF THE I 29 CORRIDOR FOR THE
ENTIRE NIGHT. THIS CONFLICTS WITH MY GOING POPS WHICH WAS A SUPER
ENSEMBLE BLEND OF THE AFOREMENTIONED MODELS. THE SLOWER ECMWF IS
BOTHERSOME...IN THAT IT WAS THE ONLY MODEL YESTERDAY WHICH KEPT
OUR FORECAST AREA DRY FOR TODAY. SO IF THE FORECAST IS IN ERROR
TONIGHT...IT WILL LIKELY BE TO KEEP THE LIGHT SNOWFALL MORE TO THE
WEST OF I 29. SOMETHING TO WATCH FOR...FOR THE UPCOMING DAY SHIFT.
AT ANY RATE...CATEGORICAL POPS ARE CERTAINLY WARRANTED MAINLY
ALONG AND WEST OF THE JAMES RIVER VALLEY...WITH RAPIDLY DECREASING
POPS EASTWARD FROM THERE. A COUPLE OF INCHES OF SNOW COULD FALL
AROUND THE CHAMBERLAIN AREA TONIGHT...WITH MAYBE AN INCH OR SO IN
THE JAMES RIVER VALLEY...TAPERING OFF TO THE EAST. CONCERNING
LOWS...THERE WILL LIKELY BE A LARGE DISCREPANCY IN TEMPERATURES
FROM WEST TO EAST. GREGORY COUNTY WITH THEIR CLOUD COVER WILL PROBABLY
STAY AROUND 25 DEGREES. CONVERSELY...SOUTHWEST MN AND THE SPENCER
IA LOCATIONS WILL LIKELY DIP BELOW 10 DEGREES AGAIN WITH MUCH
CLEARER SKIES. LOWS ARE THE TRICKIEST ALONG THE I 29 CORRIDOR...
WHO IS CAUGHT ON WHAT COULD BE THE EDGE OF SOME THICKER CLOUD
COVER FOR AT LEAST PART OF THE NIGHT.
.LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 342 AM CDT THU MAR 21 2013
ANOTHER SEASONABLY CHILLY DAY ON FRIDAY IS CERTAIN. THURSDAY
NIGHTS SHORT WAVE EXITS OUR EASTERN ZONES ABOUT MIDDAY...WHICH
SHOULD BRING AN END TO THE SNOWFALL POTENTIAL IN OUR FORECAST AREA
BY MID AFTERNOON. THEN IT IS JUST WAITING FOR THE NEXT...MORE
SIGNIFICANT UPPER TROUGH TO DIG DOWN THE SPINE OF THE ROCKIES
FRIDAY NIGHT AND SATURDAY. THE WAVE THEN MOVES ACROSS THE CENTRAL
PLAINS FOR THE REMAINDER OF THE WEEKEND. THE SNOWFALL POTENTIAL IS
GOING TO HAVE A HECK OF A TIME MAKING IT NORTHWARD INTO OUR
FORECAST AREA LATE FRIDAY NIGHT THROUGH SATURDAY NIGHT. ALTHOUGH
THE MID AND UPPER WAVE IS DECENT...HIGH PRESSURE IN SOUTHERN
CANADA IS DRAINING DOWN A DRY...COLD LOW LEVEL FETCH OF AIR
CUTTING OFF A DEEP MOISTURE SUPPLY. IT APPEARS THE ONLY CHANCE FOR
SNOW WILL BE ALONG OUR FAR SOUTHERN ZONES SATURDAY THROUGH SUNDAY.
IF THE ECMWF IS CORRECT... THE CHANCE FOR SNOW WILL BE JUST
FLURRIES FOR OUR SOUTHERN ZONES. SO IN GENERAL...THE WEEKEND LOOKS
TO CONTINUE THE CHILLY WEATHER... WITH SEASONABLY COOL WEATHER
LASTING RIGHT INTO EARLY NEXT WEEK. ELIMINATED ALL MENTION OF POPS
FROM SUNDAY NIGHT ONWARD.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z FRIDAY AFTERNOON)
ISSUED AT 1228 PM CDT THU MAR 21 2013
VFR CONDITIONS ARE EXPECTED TO PREVAIL THROUGH THIS
EVENING. DETERIORATING CONDITIONS MOVING SLOWLY FROM WEST TO EAST
WILL MOVE IN OVERNIGHT AND FRIDAY MORNING ALONG WITH LIGHT SNOW.
MVFR CIGS WILL THEN PREVAIL THROUGH THE END OF THE TAF PERIOD...AND
SOME IFR VSBYS WILL BE POSSIBLE FOR A FEW HOUR PERIOD WITH THE
HEAVIEST SNOW...MAINLY WEST OF A LINE FROM KBKX TO KFSD TO KSUX.
&&
.FSD WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
MN...NONE.
IA...NONE.
NE...NONE.
&&
$$
UPDATE...AEB
SHORT TERM...MJF
LONG TERM...MJF
AVIATION...AEB
AREA FORECAST DISCUSSION
NWS HOUSTON/GALVESTON TX
345 PM CDT THU MAR 21 2013
.DISCUSSION...
DEEPENING SURFACE PRESSURES OVER THE TX/OK PANHANDLES AND EASTERN
NM/CO IS THE BEGINNING OF A DEVELOPING WESTERN TX DRYLINE AND
NORTHEASTERN TX WARM FRONT AS THE SURFACE LOW CENTER WILL TRACK
EASTWARD ACROSS THE RED RIVER VALLEY THROUGH LATE FRIDAY. WITH
SOUTHEASTERN TEXAS FALLING WITHIN THE WARM SECTOR THROUGH AN
EVENTUAL MID-LATE SATURDAY COLD FRONTAL PASSAGE...RAIN/STORM
CHANCES WILL BE ON THE RISE OVER THE NEXT 48 HOURS OR SO.
ENERGY CARVING OUT A GREAT BASIN SHORTWAVE TROUGH...THIS FEATURE
TO DEEPEN INTO A SIGNIFICANT ENOUGH 5H OPEN WAVE TROUGH AS IT
COMES OUT OF THE ROCKIES SATURDAY. AN ACTIVE LONGITUDINAL SOUTHERN
JET BRANCH OVER NORTHERN TEXAS...COUPLED WITH A NW-TO-SE ORIENTED
JET STREAK MOVING OUT OF THE CENTRAL ROCKIES...MAY PROVIDE ENOUGH
UPPER LEVEL SUPPORT (COORDINATING RR AND LF QUADS) OVER NORTH
CENTRAL TEXAS TO GENERATE DECENT NORTHERN FORECAST CONVECTION.
COMBINE THIS ENERGY WITH FAIRLY SATURATE LOWER LEVELS (UNSEASONABLY
HIGH 1.25-1.30 INCH PWAT RANGE)...WITH DECENT MID-LEVEL LAPSE
RATES...THE POTENTIAL FOR ACTIVE SATURDAY WEATHER IS ALIVE. OF
COURSE...THE NEAR 8H WARM NOSE WILL BE THE DECIDER. AS OF NOW...
MODEL SOUNDINGS DEPICT NEAR 1K CAPE AND A NEAR 70 F CAP-BREAKER
SURFACE TEMPERATURE. ONGOING FORECAST CALLS FOR DOWNSTREAM AFTERNOON
TEMPERATURES TO REACH THE LOWER 80S SO WE`LL SEE IF THAT IS ENOUGH
TO INITIATE MORE ACTIVE THUNDERSTORM ACTIVITY.
A LATE SATURDAY OR EARLY SUNDAY AGGRESSIVE COLD FRONTAL PASSAGE
WILL PUT AN END TO ANY RAINY/STORMY WEATHER...WHILE SIGNIFICANTLY
STRENGTHENING NORTHERLY WINDS...A BACKING HIGH INTRODUCES A VERY
DRY AND COOL CONTINENTAL AIR MASS. THE FIRST FULL WEEK OF SPRING
BEGINS WITH AN ELEVATED FIRE THREAT SUNDAY (SEE BELOW) AND BELOW
NORMAL TEMPERATURE BEHAVIOR. FROM THE LOW TO MID 80S SATURDAY TO
NEAR 60 F MAX TEMPS MON-TUE...MID-UPPER 60S SATURDAY MORNING TO
30/40S BY MONDAY MORNING UNDER A WEAKER NORTH-NORTHEAST WIND. THE
HIGHEST CONFIDENCE IS WITH THE RAIN FORECAST. PER MOUNTING WESTERN
UPPER RIDGING...SATURDAY`S RAIN WILL MOST LIKELY BE THE LAST FOR
THE REMAINDER OF THE MONTH. SIGHTS WILL BE SET ON APRIL FOR ANOTHER
ROUND OF THE WET STUFF. 31
&&
.MARINE...
CAUTION FLAGS WILL REMAIN UP THROUGH THIS EVENING. WINDS AND SEAS
SHOULD SLOWLY DIMINISH FRIDAY THROUGH SATURDAY AHEAD OF THE NEXT
COLD FRONT. THIS FRONT SHOULD PUSH OFF THE COAST SATURDAY NIGHT
INTO SUNDAY MORNING. ADVISORIES WILL BE NEEDED FOR STRONG NORTH
WINDS AND BUILDING SEAS BEHIND THE FRONT. CAUTION OR ADVISORY FLAGS
ARE ANTICIPATED FOR THE FIRST HALF OF NEXT WEEK DUE TO MODERATE TO
STRONG NORTHEAST WINDS AND ELEVATED SEAS. 42
&&
.FIRE WEATHER...
AFTER THE PASSAGE OF A STRONG COLD FRONT ON SATURDAY NIGHT...ELEVATED
FIRE WEATHER DANGER LOOKS POSSIBLE ON SUNDAY DUE TO GUSTY NORTH WINDS
AND RELATIVE HUMIDITY VALUES DROPPING TOWARDS A 20%-30% RANGE. A FIRE
WEATHER WATCH AND/OR A RED FLAG WARNING MIGHT BE NEEDED. 42
&&
.PRELIMINARY POINT TEMPS/POPS...
COLLEGE STATION (CLL) 63 81 60 81 49 / 20 20 20 50 10
HOUSTON (IAH) 64 82 65 82 54 / 20 20 20 40 20
GALVESTON (GLS) 65 74 66 74 60 / 10 20 20 40 10
&&
.HGX WATCHES/WARNINGS/ADVISORIES...
TX...NONE.
GM...SMALL CRAFT SHOULD EXERCISE CAUTION UNTIL 9 PM CDT THIS EVENING
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 SHOULD EXERCISE CAUTION UNTIL MIDNIGHT CDT TONIGHT
FOR THE FOLLOWING ZONES: WATERS FROM FREEPORT TO THE
MATAGORDA SHIP CHANNEL 20 NM TO 60 NM...WATERS FROM HIGH
ISLAND TO FREEPORT 20 TO 60 NM.
&&
$$
DISCUSSION...31/42
AREA FORECAST DISCUSSION
NWS FORT WORTH TX
319 PM CDT THU MAR 21 2013
.DISCUSSION...
BREEZY AND MOSTLY CLOUDY CONDITIONS CONTINUE ACROSS THE REGION
THIS EVENING BUT SOME CHANGES ARE STILL EXPECTED BY THE LATE
AFTERNOON AND EVENING HOURS. THE SURFACE LOW REMAINS OVER THE
TEXAS PANHANDLE WITH THE LEADING EDGE OF THE DRYLINE NOW LOCATED
ROUGHLY ALONG A LINE FROM VERNON TO SAN ANGELO. DEWPOINTS CONTINUE
TO INCREASE INTO THE LOWER 50S AHEAD OF THE DRYLINE BUT
INSTABILITY IS STILL LACKING. SATELLITE IMAGERY DEPICTS EVIDENCE
OF INCREASING LIFT APPROACHING THE REGION FROM THE WEST. SOME LOW
LEVEL CUMULUS HAS NOW DEVELOPED IN NORTHWEST TEXAS AND SOUTHWEST
OKLAHOMA AND MID LEVEL CLOUDS OVER WEST CENTRAL TEXAS ARE
LOOKING MORE ROBUST. INITIATION IS STILL POSSIBLE NEAR THE DRYLINE
LATE THIS AFTERNOON...AMONGST BREAKS IN THE MID LEVEL CLOUD DECK
BUT THE WINDOW FOR SEVERE POTENTIAL IS DECREASING. INITIATION NEAR
THE DRYLINE JUST WEST OF OUR CWA LIKELY WILL NOT BE UNTIL AFTER 5
PM AND THE SEVERE THREAT WILL BE DIMINISHING WITH THE LOSS OF
HEATING BY 8-9 PM. CONSIDERING THE LATEST TRENDS...WITH THE MID
LEVEL CLOUD COVER THAT IS STRETCHING BACK WEST...SBCAPES NEAR 1000
J/KG AS PREVIOUSLY PREDICTED MAY BE TOO HIGH AND VALUES WILL
REMAIN CLOSER TO 500-800 J/KG. CONVERGENCE ALONG THE DRYLINE IS
NOT VERY GOOD AT THIS TIME AS THE WINDS AHEAD OF THE DRYLINE ARE
ALSO FROM THE SOUTHWEST. THE RAP SHOWS THE SURFACE LOW REMAINING
IN THE TEXAS PANHANDLE FOR THE NEXT FEW HOURS WHICH MEANS THE SURFACE
WINDS WILL LIKELY NOT HAVE A CHANCE TO BACK AS THE DRYLINE MOVES
CLOSER. HOWEVER...WITH STRONG SHEAR...LIFT FROM A SERIES OF
SHORTWAVES MOVING NEAR THE REGION AND THE POTENTIAL FOR INCREASING
INSTABILITY OVER THE NEXT FEW HOURS...STILL EXPECT TO SEE A FEW
THUNDERSTORMS OVER OUR NORTHWESTERN COUNTIES WITH A FEW STRONG TO
SEVERE STORMS POSSIBLE. ANY STORMS THAT DO DEVELOP WILL LIKELY
MOVE EAST OR SOUTHEAST. LARGE HAIL AND DAMAGING WINDS WILL BE THE
MAIN THREATS.
EXPECT THE THUNDERSTORM ACTIVITY TO WANE FAIRLY QUICKLY AROUND OR
AFTER SUNSET BUT ADDITIONAL SHOWERS AND THUNDERSTORMS WILL BE
POSSIBLE OVER THE NORTHERN HALF OF THE REGION OVERNIGHT. THE
HIGHEST CHANCES FOR RAIN CONTINUE TO BE OVER THE NORTHEASTERN
COUNTIES. CANNOT RULE OUT A STRONG STORM OR TWO PRODUCING SMALL
HAIL AND/OR GUSTY WINDS BUT THE INSTABILITY OVERNIGHT IS FAIRLY
WEAK. A COLD FRONT WILL MOVE INTO THE REGION LATE TONIGHT AND
CONTINUE TO PROGRESS SOUTH THROUGH THE DAY TOMORROW. THERE
CONTINUES TO BE A CHANCE FOR RAIN AND ISOLATED THUNDERSTORMS OVER
THE EASTERN HALF OF THE REGION TOMORROW. WE COULD SEE A STRONG
STORM OR TWO OVER OUR FAR SOUTHEASTERN COUNTIES TOMORROW AFTERNOON
AHEAD OF THE FRONT.
THE FRONT WILL STALL JUST SOUTH OF THE CWA FRIDAY NIGHT AND THEN
RETREAT NORTH AS A WARM FRONT ON SATURDAY. AS THE WARM FRONT LIFTS
NORTH...WARM AIR ADVECTION OVER THE COOL SURFACE LAYER WILL RESULT
IN SCATTERED RAIN ACTIVITY THROUGHOUT THE DAY WITH ISOLATED
THUNDERSTORMS POSSIBLE. HIGHEST RAIN CHANCES WILL BE OVER THE
EASTERN HALF OF THE REGION. A STRONGER COLD FRONT WILL PUSH ACROSS
THE REGION SATURDAY NIGHT. THE RAIN WILL BE ENDING FROM WEST TO
EAST DURING THE DAY AS A DRYLINE MOVES ACROSS THE REGION. MUCH
COOLER AND DRIER AIR WILL SETTLE INTO THE REGION FOR SEVERAL DAYS
WITH TEMPERATURES FALLING BELOW NORMAL FOR AT LEAST THE FIRST HALF
OF NEXT WEEK. A FREEZE IS NOT EXPECTED REGION-WIDE ON ANY GIVEN
NIGHT BUT NEAR FREEZING TEMPERATURES WILL BE POSSIBLE MAINLY OVER
THE NORTHWESTERN HALF OF THE CWA SUNDAY AND MONDAY NIGHTS. TEMPERATURES
WILL START TO WARM LATER IN THE WEEK AND THE GFS IS MUCH FASTER TO
WARM TEMPERATURES THAN THE ECMWF.
82/JLD
&&
.PRELIMINARY POINT TEMPS/POPS...
DALLAS-FT. WORTH, TX 57 64 47 68 42 / 30 20 20 50 10
WACO, TX 62 71 50 74 42 / 10 20 20 50 5
PARIS, TX 48 58 45 58 37 / 60 30 20 50 20
DENTON, TX 51 60 45 65 39 / 40 20 20 40 10
MCKINNEY, TX 54 60 45 62 40 / 50 20 20 50 10
DALLAS, TX 58 64 48 68 43 / 30 20 20 50 10
TERRELL, TX 58 64 48 65 42 / 30 30 20 50 10
CORSICANA, TX 62 71 50 69 43 / 20 20 20 50 10
TEMPLE, TX 62 76 52 76 41 / 10 20 20 40 5
MINERAL WELLS, TX 50 63 46 74 39 / 40 10 20 30 10
&&
.FWD WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
05/82
AREA FORECAST DISCUSSION
NWS FORT WORTH TX
116 PM CDT THU MAR 21 2013
.AVIATION...
CONCERNS THE NEXT 24 HOURS INCLUDE WIND SPEEDS AND
SHIFTS...CONVECTIVE CHANCES AROUND THE DFW METRO THIS
EVENING...AND TIMING OF LOWER CIGS BACK ACROSS NORTH TEXAS.
SOUTH-SOUTHEAST WINDS AROUND 15-20 KTS WITH GUSTS IN EXCESS OF 30
KTS WILL LIKELY CONTINUE AHEAD OF AN APPROACHING SURFACE LOW AND
DRYLINE THROUGH EARLY EVENING. AS THE SYSTEM MOVES SOUTHEAST
TOWARD THE RED RIVER THIS EVENING...ISOLATED TO SCATTERED STRONG
TO SEVERE STORMS WILL DEVELOP NORTHWEST OF THE DFW METRO AND MOVE
GENERALLY EAST. WILL MAINTAIN CURRENT TIMING OF VCTS BY 00Z...BUT
LIMIT THE WINDOW TO 2 HRS WITH LOW CONFIDENCE ON COVERAGE ACROSS
THE METRO. WACO WILL REMAIN DRY.
VFR CIGS EXPECTED TO PREVAIL THROUGH MID EVENING...BEFORE COOLING
OF THE BOUNDARY LAYER HELPS LOWER THEM INTO THE MVFR CATEGORY BY
MIDNIGHT AS THE COLD FRONT APPROACHES FROM THE NORTH. SUB-BOUNDARY
LAYER MOISTURE LOOKS RICHER AT WACO AROUND SUNRISE AND BEFORE
FROPA AND HAVE INTRODUCED A BRIEF WINDOW FOR IFR CIGS. BEHIND THE
FRONT SATURDAY...MVFR CIGS SHOULD PREVAIL THROUGH MIDDAY. ENOUGH
WARMING BY AFTERNOON SHOULD ALLOW CIGS TO RISE INTO THE LOW VFR
CATEGORY BETWEEN 030-040 KFT.
AS NIGHTFALL OCCURS...WINDS WILL VEER SOUTHEAST AND DIMINISH TO
BETWEEN 10-15 KTS. A COLD FRONT WILL ARRIVE INTO DFW METRO
AIRPORTS BY OR JUST BEFORE SUNRISE FRIDAY MORNING...THEN INTO WACO
BY MID MORNING. NORTHWEST WINDS 10-15 KTS ARE EXPECTED BEHIND THE
COLD FRONT.
05/
&&
.UPDATE...
AT 11 AM...BREEZY SOUTH AND SOUTHEAST WINDS WERE OCCURRING ACROSS
THE REGION UNDER MOSTLY CLOUDY SKIES BUT THE CLOUDS WERE STARTING
TO THIN AND BREAK ACROSS THE SOUTHERN AND WESTERN COUNTIES. A
SURFACE LOW WAS LOCATED IN THE TEXAS PANHANDLE WITH A DRYLINE
EXTENDING SOUTH. DURING THE AFTERNOON...THE SURFACE LOW WILL
CONTINUE TO TRACK EAST-SOUTHEAST AND DEEPEN AS IT MOVES. THIS WILL
DRAG THE DRYLINE INTO OUR FAR WESTERN COUNTIES THIS AFTERNOON. LOW
AND MID 50S DEWPOINTS WERE ALREADY SURGING NORTH THROUGH CENTRAL
TEXAS...AS FAR NORTH AS WACO. THESE HIGHER DEWPOINTS WILL CONTINUE
TO ADVECT NORTH AND NORTHWEST THIS AFTERNOON WITH MID 50 DEWPOINTS
FORECAST OVER MUCH OF THE WESTERN HALF OF THE REGION BY LATE
AFTERNOON. THESE DEWPOINT VALUES ARE SLIGHTLY HIGHER THAN
PREVIOUSLY FORECAST WHICH WILL INCREASE THE INSTABILITY ALONG THE
DRYLINE BY THE LATE AFTERNOON HOURS. THE LATEST RAP AND NAM RUNS
SUGGEST SURFACE BASED CAPE VALUES WILL REACH AROUND 800-1000 J/KG
ALONG THE DRYLINE IN OUR FAR NORTHWEST COUNTIES WITH A WEAK OR
ERODED CAP. WITH A SHORTWAVE APPROACHING THE REGION...WE SHOULD
SEE CONVECTIVE INITIATION OVER THE FAR NORTHWESTERN COUNTIES /NEAR
THE DRYLINE AND SURFACE LOW/ BY THE LATE AFTERNOON
HOURS...POSSIBLY AS EARLY AS 3-4 PM BUT MORE LIKELY CLOSER TO 5-6
PM. GIVEN THE INCREASING INSTABILITY PARAMETERS AND SUFFICIENT
SHEAR VALUES...SOME STORMS WILL LIKELY REACH SEVERE LIMITS WITH
LARGE HAIL AND DAMAGING WINDS THE MAIN THREATS.
THE STORMS WILL TRACK EAST OR EAST-SOUTHEAST THROUGH THE EARLY
EVENING HOURS AND THEN WEAKEN AS WE LOOSE THE INSTABILITY WITH THE
LOSS OF HEATING. AFTER SUNSET...THE MAIN FOCUS FOR LIFT WILL THEN
SHIFT TO OUR NORTHEASTERN COUNTIES WHERE A SURFACE BOUNDARY WILL
BECOME BETTER DEFINED UNDER THE INFLUENCE OF THE SHORTWAVE. SEVERE
STORMS ARE CURRENTLY NOT EXPECTED OVERNIGHT DUE TO A WELL CAPPED
ENVIRONMENT BUT WILL REASSESS THIS POTENTIAL WITH THE AFTERNOON
PACKAGE.
FOR THE UPDATE...EXPANDED THE HIGHER POPS THIS AFTERNOON FARTHER
SOUTH AND WEST SOME. ADDITIONAL CLOUD COVER IS MOVING NORTH
THROUGH CENTRAL TEXAS AND WILL SPREAD OVER OUR SOUTHERN ZONES THIS
AFTERNOON...THUS DECREASED TEMPERATURES OVER THE SOUTHERN COUNTIES
A DEGREE OR TWO.
82/JLD
&&
.PREV DISCUSSION... /ISSUED 410 AM CDT THU MAR 21 2013/
CHANGES ARE ON THE WAY ACROSS NORTH TEXAS THIS MORNING AS SURFACE
PRESSURES BEGIN TO FALL IN RESPONSE TO DEEPENING LEE CYCLONE.
SOUTHERLY WINDS ARE INCREASING WHICH WILL ALLOW FOR A RAPID
INCREASE IN DEWPOINTS OVER THE NEXT SEVERAL HOURS. THICK HIGH
CLOUDS CONTINUE TO STREAM OVERHEAD AND THIS IS LIKELY TO CONTINUE
THROUGH MUCH OF THE DAY. BY LATE THIS AFTERNOON THE SURFACE LOW
WILL BE LOCATED BETWEEN CHILDRESS AND WICHITA FALLS WITH A DRYLINE
EXTENDING FROM THE LOW ACROSS OUR FAR WEST/NORTHWEST COUNTIES.
MODEL GUIDANCE SUGGESTS THAT A WEAK IMPULSE EMBEDDED IN THE FAST
MID/UPPER FLOW WILL CROSS THE RED RIVER VALLEY LATE THIS AFTERNOON
COINCIDING WITH PEAK HEATING AND AN EASTWARD BULGE IN DRYLINE.
WHILE CLOUD COVER IS EXPECTED TO BE AN INHIBITING FACTOR... STRONG
LOW LEVEL WARM ADVECTION FROM MIDDAY THROUGH EARLY EVENING SHOULD
ALLOW SURFACE TEMPS TO WARM INTO THE LOWER 80S ACROSS THE
NORTHWEST THIS AFTERNOON. THIS WARM ADVECTION AND FORCING ALOFT
FROM THE WEAK IMPULSE SHOULD BE SUFFICIENT TO WEAKEN WHAT IS
INITIALLY A STRONG CAP...AND ALLOW CONVECTION TO DEVELOP IN THE
22-00Z TIMEFRAME ACROSS THE NORTHWEST COUNTIES. ALL OF THE HIGH
RESOLUTION CONVECTION ALLOWING GUIDANCE INDICATES THAT THIS WILL
HAPPEN SO HAVE RAISED POPS ACROSS THE NORTHWEST AND RED RIVER
AREAS THROUGH LATE THIS EVENING. FORECAST SOUNDINGS FROM THIS AREA
YIELD ANYWHERE FROM 500-1000J/KG OF MIXED LAYER CAPE AND INDICATE
CONVECTION SHOULD BE SOMEWHAT HIGH BASED WITH LCLS AROUND 800MB.
GIVEN THE DEEP LAYER STRONG WIND FIELDS AND STEEP LAPSE RATES...
DISCRETE SUPERCELL STRUCTURES ARE POSSIBLE POSING MAINLY A LARGE
HAIL AND DAMAGING WIND THREAT. LACK OF MORE IMPRESSIVE SURFACE
BASED INSTABILITY SUGGESTS THAT OVERALL SEVERE WEATHER THREAT IS
ON THE LOW END. SURFACE BASED STORMS SHOULD QUICKLY BECOME
ELEVATED AFTER SUNSET WITH SEVERE THREAT DIMINISHING.
THIS SURFACE LOW WILL MOVE INTO THE ARKLATEX OVERNIGHT INTO FRIDAY
WITH A COLD FRONT SLIDING THROUGH NORTH TEXAS. THE FRONT IS LIKELY
TO BE DRAPED ACROSS THE SOUTHERN COUNTIES DURING THE DAY FRIDAY
WITH NORTHERN AREAS STAYING IN THE 60S AND SOUTHERN AREAS WARMING
INTO THE 80S. WITH THE LACK OF ANY APPRECIABLE FORCING THINK
PRECIP CHANCES WILL BE QUITE LOW ON FRIDAY DESPITE INCREASING
INSTABILITY. FORECAST SOUNDINGS INDICATE MOST AREAS WILL REMAIN
CAPPED.
BY SATURDAY A STRONG S/W WILL DIG INTO THE 4-CORNERS REGION WITH
THE FRONTAL BOUNDARY RETREATING AS A WARM FRONT. THE GUIDANCE
CONTINUES TO STRUGGLE REACHING A CONSENSUS AS TO HOW MUCH OF A
WARM SECTOR RETURNS TO NORTH TEXAS. GFS/CANADIAN RETREAT THE FRONT
THROUGH MOST OF THE AREA WITH NORTH TEXAS MOIST AND UNSTABLE. THE
ECMWF IS SLOWER WITH THE FRONT AND KEEP MOST CONVECTIVE ACTIVITY
ELEVATED ABOVE A SHALLOW COOL LAYER. WITH THE GFS TRENDING IN THE
GENERAL DIRECTION OF THE ECMWF OVER THE LAST 48 HOURS...HAVE SIDED
MORE IN LINE WITH THE ECMWF. CURRENT FORECAST WILL SHOW THE WARM
SECTOR ACROSS THE SOUTHERN HALF OF THE CWA WITH HIGHEST POPS IN
THE MORNING. AS THE S/W MOVES THROUGH THE SOUTHERN PLAINS BY EARLY
EVENING...MORE ROBUST CONVECTION IS LIKELY TO DEVELOP ACROSS THE
EASTERN COUNTIES BEFORE MOVING EAST OUT OF THE AREA. SEVERE
THUNDERSTORMS WILL BE POSSIBLE SATURDAY AFTERNOON/EVENING
PRIMARILY ACROSS THE EASTERN COUNTIES.
AS THIS WHOLE SYSTEM MOVES EAST BY SUNDAY...A STRONG COLD FRONT
MOVES THROUGH THE AREA. SUNDAY INTO THE MIDDLE OF NEXT WEEK LOOKS
QUITE COOL WITH HIGHS IN THE 50S TO MID 60S AND OVERNIGHT LOWS IN
THE 30S. FREEZING TEMPERATURES ARE LIKELY ESPECIALLY IN OUTLYING
AREAS MONDAY MORNING.
DUNN
&&
.PRELIMINARY POINT TEMPS/POPS...
DALLAS-FT. WORTH, TX 74 59 67 50 64 / 10 40 20 20 50
WACO, TX 74 62 78 54 77 / 10 10 10 20 50
PARIS, TX 60 51 62 46 56 / 20 60 20 20 50
DENTON, TX 72 56 62 46 63 / 30 50 20 20 40
MCKINNEY, TX 71 57 62 48 62 / 10 50 20 20 50
DALLAS, TX 75 61 68 51 65 / 10 40 20 20 50
TERRELL, TX 68 60 70 50 65 / 10 30 20 20 50
CORSICANA, TX 74 62 78 55 73 / 10 20 20 20 50
TEMPLE, TX 75 62 81 57 82 / 10 10 10 20 40
MINERAL WELLS, TX 78 54 67 47 69 / 40 30 10 20 30
&&
.FWD WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
05/82
AREA FORECAST DISCUSSION...UPDATED
NWS FORT WORTH TX
1120 AM CDT THU MAR 21 2013
.UPDATE...
AT 11 AM...BREEZY SOUTH AND SOUTHEAST WINDS WERE OCCURRING ACROSS
THE REGION UNDER MOSTLY CLOUDY SKIES BUT THE CLOUDS WERE STARTING
TO THIN AND BREAK ACROSS THE SOUTHERN AND WESTERN COUNTIES. A
SURFACE LOW WAS LOCATED IN THE TEXAS PANHANDLE WITH A DRYLINE
EXTENDING SOUTH. DURING THE AFTERNOON...THE SURFACE LOW WILL
CONTINUE TO TRACK EAST-SOUTHEAST AND DEEPEN AS IT MOVES. THIS WILL
DRAG THE DRYLINE INTO OUR FAR WESTERN COUNTIES THIS AFTERNOON. LOW
AND MID 50S DEWPOINTS WERE ALREADY SURGING NORTH THROUGH CENTRAL
TEXAS...AS FAR NORTH AS WACO. THESE HIGHER DEWPOINTS WILL CONTINUE
TO ADVECT NORTH AND NORTHWEST THIS AFTERNOON WITH MID 50 DEWPOINTS
FORECAST OVER MUCH OF THE WESTERN HALF OF THE REGION BY LATE
AFTERNOON. THESE DEWPOINT VALUES ARE SLIGHTLY HIGHER THAN
PREVIOUSLY FORECAST WHICH WILL INCREASE THE INSTABILITY ALONG THE
DRYLINE BY THE LATE AFTERNOON HOURS. THE LATEST RAP AND NAM RUNS
SUGGEST SURFACE BASED CAPE VALUES WILL REACH AROUND 800-1000 J/KG
ALONG THE DRYLINE IN OUR FAR NORTHWEST COUNTIES WITH A WEAK OR
ERODED CAP. WITH A SHORTWAVE APPROACHING THE REGION...WE SHOULD
SEE CONVECTIVE INITIATION OVER THE FAR NORTHWESTERN COUNTIES /NEAR
THE DRYLINE AND SURFACE LOW/ BY THE LATE AFTERNOON
HOURS...POSSIBLY AS EARLY AS 3-4 PM BUT MORE LIKELY CLOSER TO 5-6
PM. GIVEN THE INCREASING INSTABILITY PARAMETERS AND SUFFICIENT
SHEAR VALUES...SOME STORMS WILL LIKELY REACH SEVERE LIMITS WITH
LARGE HAIL AND DAMAGING WINDS THE MAIN THREATS.
THE STORMS WILL TRACK EAST OR EAST-SOUTHEAST THROUGH THE EARLY
EVENING HOURS AND THEN WEAKEN AS WE LOOSE THE INSTABILITY WITH THE
LOSS OF HEATING. AFTER SUNSET...THE MAIN FOCUS FOR LIFT WILL THEN
SHIFT TO OUR NORTHEASTERN COUNTIES WHERE A SURFACE BOUNDARY WILL
BECOME BETTER DEFINED UNDER THE INFLUENCE OF THE SHORTWAVE. SEVERE
STORMS ARE CURRENTLY NOT EXPECTED OVERNIGHT DUE TO A WELL CAPPED
ENVIRONMENT BUT WILL REASSESS THIS POTENTIAL WITH THE AFTERNOON
PACKAGE.
FOR THE UPDATE...EXPANDED THE HIGHER POPS THIS AFTERNOON FARTHER
SOUTH AND WEST SOME. ADDITIONAL CLOUD COVER IS MOVING NORTH
THROUGH CENTRAL TEXAS AND WILL SPREAD OVER OUR SOUTHERN ZONES THIS
AFTERNOON...THUS DECREASED TEMPERATURES OVER THE SOUTHERN COUNTIES
A DEGREE OR TWO.
82/JLD
&&
.AVIATION...
IN ADDITION TO MID-HIGH CLOUDS...A VFR CIG NEAR 060 SHOULD BE IN
PLACE FOR MUCH OF THE DAY. SE WINDS NEAR 10KT THIS MORNING WILL
BECOME S/SE AND INCREASE TO 20KT AND GUSTY BY LATE MORNING. THE
060 VFR CIG WILL GRADUALLY LOWER AFTER SUNSET TO 040 BY 4Z AND TO
MVFR BY 6-7Z TONIGHT.
A SURFACE LOW WILL TRACK VERY NEAR THE METROPLEX LATE TONIGHT SO
WINDS WILL DEFINITELY DIMINISH AFTER 6Z/MIDNIGHT. IT IS UNCLEAR IF
WINDS WILL BACK TO THE EAST OR VEER TO THE WEST AHEAD OF THE
FRONT...BUT FOR NOW HAVE SIDED WITH THE FORECAST SOLUTIONS THAT
INDICATE VEERING WINDS. THE COLD FRONT SHOULD MOVE THROUGH THE
METROPLEX AROUND SUNRISE FRIDAY MORNING WITH NORTH WINDS AT
10-15KT. WITH WESTERLY WINDS ABOVE THE BOUNDARY LAYER AHEAD OF THE
FRONT...THE MVFR CIGS MAY TEMPORARILY CLEAR THE METROPLEX.
CONFIDENCE IN THIS IS LOW AND THUS HAVE LEFT MVFR IN THROUGH THE
NIGHTTIME HOURS FOR NOW. MVFR CIGS WILL PREVAIL BEHIND THE FRONT
FRIDAY MORNING.
FINAL CONCERN IS CONVECTIVE POTENTIAL. BELIEVE BRUNT OF THE
ACTIVITY WILL FIRE NW OF THE METROPLEX AND TRACK GENERALLY WEST TO
EAST. THIS WOULD PUT THE LIKELY TRACK OF THE STORMS JUST TO THE
NORTH OF THE METROPLEX TAF SITES. GIVEN INHERENT UNCERTAINTIES
WITH CONVECTIVE FORECASTS AT THIS SPATIAL SCALE...BELIEVE IT
WOULD BE PRUDENT TO INCLUDE VCTS FOR AFW/DFW/DAL TAF SITES FROM
APPROX 0Z-3Z/7PM-10PM CDT.
TR.92
&&
.PREV UPDATE...
.UPDATE...
QUICK UPDATE TO INCLUDE SOME SCATTERED SHOWERS FOR THE MORNING
HOURS ACROSS THE EASTERN HALF OF THE CWA BASED ON RADAR DATA AND
LATEST SOUNDING DATA. SCATTERED SHOWERS HAVE DEVELOPED OVER THE
LAST HOUR FROM NEAR GAINESVILLE TO PALESTINE. SURFACE DEWPOINTS
ARE IN THE 20S IN MANY AREAS BUT THE 12Z FWD SOUNDING INDICATES A
SATURATED LAYER AROUND 750MB AND UNCAPPED ELEVATED CAPE OF ABOUT
200J/KG LIFTING FROM THIS LEVEL. RAP MODEL GUIDANCE INDICATES
STRONG WARM ADVECTION THROUGH THIS LAYER SO WOULD EXPECT THE
SCATTERED CONVECTIVE SHOWERS TO CONTINUE. AT THIS TIME WITH A LACK
OF APPRECIABLE ADDITIONAL FORCING...THINK MOST OF THIS ACTIVITY
WILL REMAIN SHOWERY IN NATURE AND WILL LEAVE OUT A MENTION OF
THUNDER. PRECIP AMOUNTS WILL BE LIGHT AS THE NEAR SURFACE LAYER TO
ABOUT 800MB IS STILL VERY DRY.
DUNN
&&
.PREV DISCUSSION... /ISSUED 410 AM CDT THU MAR 21 2013/
CHANGES ARE ON THE WAY ACROSS NORTH TEXAS THIS MORNING AS SURFACE
PRESSURES BEGIN TO FALL IN RESPONSE TO DEEPENING LEE CYCLONE.
SOUTHERLY WINDS ARE INCREASING WHICH WILL ALLOW FOR A RAPID
INCREASE IN DEWPOINTS OVER THE NEXT SEVERAL HOURS. THICK HIGH
CLOUDS CONTINUE TO STREAM OVERHEAD AND THIS IS LIKELY TO CONTINUE
THROUGH MUCH OF THE DAY. BY LATE THIS AFTERNOON THE SURFACE LOW
WILL BE LOCATED BETWEEN CHILDRESS AND WICHITA FALLS WITH A DRYLINE
EXTENDING FROM THE LOW ACROSS OUR FAR WEST/NORTHWEST COUNTIES.
MODEL GUIDANCE SUGGESTS THAT A WEAK IMPULSE EMBEDDED IN THE FAST
MID/UPPER FLOW WILL CROSS THE RED RIVER VALLEY LATE THIS AFTERNOON
COINCIDING WITH PEAK HEATING AND AN EASTWARD BULGE IN DRYLINE.
WHILE CLOUD COVER IS EXPECTED TO BE AN INHIBITING FACTOR... STRONG
LOW LEVEL WARM ADVECTION FROM MIDDAY THROUGH EARLY EVENING SHOULD
ALLOW SURFACE TEMPS TO WARM INTO THE LOWER 80S ACROSS THE
NORTHWEST THIS AFTERNOON. THIS WARM ADVECTION AND FORCING ALOFT
FROM THE WEAK IMPULSE SHOULD BE SUFFICIENT TO WEAKEN WHAT IS
INITIALLY A STRONG CAP...AND ALLOW CONVECTION TO DEVELOP IN THE
22-00Z TIMEFRAME ACROSS THE NORTHWEST COUNTIES. ALL OF THE HIGH
RESOLUTION CONVECTION ALLOWING GUIDANCE INDICATES THAT THIS WILL
HAPPEN SO HAVE RAISED POPS ACROSS THE NORTHWEST AND RED RIVER
AREAS THROUGH LATE THIS EVENING. FORECAST SOUNDINGS FROM THIS AREA
YIELD ANYWHERE FROM 500-1000J/KG OF MIXED LAYER CAPE AND INDICATE
CONVECTION SHOULD BE SOMEWHAT HIGH BASED WITH LCLS AROUND 800MB.
GIVEN THE DEEP LAYER STRONG WIND FIELDS AND STEEP LAPSE RATES...
DISCRETE SUPERCELL STRUCTURES ARE POSSIBLE POSING MAINLY A LARGE
HAIL AND DAMAGING WIND THREAT. LACK OF MORE IMPRESSIVE SURFACE
BASED INSTABILITY SUGGESTS THAT OVERALL SEVERE WEATHER THREAT IS
ON THE LOW END. SURFACE BASED STORMS SHOULD QUICKLY BECOME
ELEVATED AFTER SUNSET WITH SEVERE THREAT DIMINISHING.
THIS SURFACE LOW WILL MOVE INTO THE ARKLATEX OVERNIGHT INTO FRIDAY
WITH A COLD FRONT SLIDING THROUGH NORTH TEXAS. THE FRONT IS LIKELY
TO BE DRAPED ACROSS THE SOUTHERN COUNTIES DURING THE DAY FRIDAY
WITH NORTHERN AREAS STAYING IN THE 60S AND SOUTHERN AREAS WARMING
INTO THE 80S. WITH THE LACK OF ANY APPRECIABLE FORCING THINK
PRECIP CHANCES WILL BE QUITE LOW ON FRIDAY DESPITE INCREASING
INSTABILITY. FORECAST SOUNDINGS INDICATE MOST AREAS WILL REMAIN
CAPPED.
BY SATURDAY A STRONG S/W WILL DIG INTO THE 4-CORNERS REGION WITH
THE FRONTAL BOUNDARY RETREATING AS A WARM FRONT. THE GUIDANCE
CONTINUES TO STRUGGLE REACHING A CONSENSUS AS TO HOW MUCH OF A
WARM SECTOR RETURNS TO NORTH TEXAS. GFS/CANADIAN RETREAT THE FRONT
THROUGH MOST OF THE AREA WITH NORTH TEXAS MOIST AND UNSTABLE. THE
ECMWF IS SLOWER WITH THE FRONT AND KEEP MOST CONVECTIVE ACTIVITY
ELEVATED ABOVE A SHALLOW COOL LAYER. WITH THE GFS TRENDING IN THE
GENERAL DIRECTION OF THE ECMWF OVER THE LAST 48 HOURS...HAVE SIDED
MORE IN LINE WITH THE ECMWF. CURRENT FORECAST WILL SHOW THE WARM
SECTOR ACROSS THE SOUTHERN HALF OF THE CWA WITH HIGHEST POPS IN
THE MORNING. AS THE S/W MOVES THROUGH THE SOUTHERN PLAINS BY EARLY
EVENING...MORE ROBUST CONVECTION IS LIKELY TO DEVELOP ACROSS THE
EASTERN COUNTIES BEFORE MOVING EAST OUT OF THE AREA. SEVERE
THUNDERSTORMS WILL BE POSSIBLE SATURDAY AFTERNOON/EVENING
PRIMARILY ACROSS THE EASTERN COUNTIES.
AS THIS WHOLE SYSTEM MOVES EAST BY SUNDAY...A STRONG COLD FRONT
MOVES THROUGH THE AREA. SUNDAY INTO THE MIDDLE OF NEXT WEEK LOOKS
QUITE COOL WITH HIGHS IN THE 50S TO MID 60S AND OVERNIGHT LOWS IN
THE 30S. FREEZING TEMPERATURES ARE LIKELY ESPECIALLY IN OUTLYING
AREAS MONDAY MORNING.
DUNN
&&
.PRELIMINARY POINT TEMPS/POPS...
DALLAS-FT. WORTH, TX 74 59 67 50 64 / 10 40 20 20 50
WACO, TX 74 62 78 54 77 / 10 10 10 20 50
PARIS, TX 60 51 62 46 56 / 20 60 20 20 50
DENTON, TX 72 56 62 46 63 / 30 50 20 20 40
MCKINNEY, TX 71 57 62 48 62 / 10 50 20 20 50
DALLAS, TX 75 61 68 51 65 / 10 40 20 20 50
TERRELL, TX 68 60 70 50 65 / 10 30 20 20 50
CORSICANA, TX 74 62 78 55 73 / 10 20 20 20 50
TEMPLE, TX 75 62 81 57 82 / 10 10 10 20 40
MINERAL WELLS, TX 78 54 67 47 69 / 40 30 10 20 30
&&
.FWD WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
05/82