Forecast Discussions mentioning any of
"HRRR" "RAP" "RR" "RUC13" "RUC" received at GSD on 03/09/13
AREA FORECAST DISCUSSION
NWS SAN FRANCISCO BAY AREA
1007 AM PST THU MAR 7 2013
.DISCUSSION...AS OF 9:10 AM PST THURSDAY...SATL IMAGERY IS INDC
THAT THE UPPER LOW IS WEST OF PT REYES AND IS SLOWLY MOVING
SOUTH...BUT WILL REMAIN OFF THE COAST. SO FAR...RADAR AND SFC OBS
ARE SHOWING ALL RAIN OFF THE COAST.
WITH THE TRACK OF THE UPPER LOW FCST TO BE WEST OF THE COAST...
THE CORE OF THE COLD AIR WILL REMAIN OVER THE OCEAN. THE QUESTION
THEN BECOMES WHAT TO DO WITH THE WINTER WEATHER ADVISORIES THAT
ARE CURRENTLY OUT FOR THE SOUTHERN MOUNTAINS. BASED ON THE LATEST
MODEL DATA IT APPEARS THAT THE SNOW LEVELS MIGHT BE HIGHER THAN
PREVIOUSLY EXPECTED. HOWEVER...ANY CONVECTIVE SHOWERS COULD DROP
THE SNOW LEVELS DOWN TEMPORARILY. BOTTOM LINE IS THAT THERE WAS
CONSIDERATION FOR DROPPING THE WINTER WEATHER ADVISORIES...HAVE
DECIDED TO LET THEM CONTINUE DUE TO THE POSSIBILITY OF CONVECTIVE
ACTIVITY DROPPING THE SNOW LEVELS LOW ENOUGH TO GET A QUICK COUPLE
OF INCHES OR MORE.
CURRENT FORECAST ON TRACK...NO UPDATES.
PREVIOUS DISCUSSION...AS OF 3:37 AM PST THURSDAY...FORECAST
FOCUS IS ON SHORTWAVE CURRENTLY LOCATED JUST WEST OF CAPE
MENDOCINO. COMPARED TO 24 HOURS AGO THE MODELS ARE NOW BRINGING
THE MAIN CORE OF THE LOW CLOSER TO THE BAY AREA LATER THIS
AFTERNOON AND EVENING...WHEREAS EARLIER RUNS WERE KEEPING THE BULK
OF THE ENERGY AND ASSOCIATED MOISTURE OFFSHORE AND THEN TOWARDS
SOUTHERN CALIFORNIA. LATEST SOLUTIONS ARE MORE IN-LINE WITH WHAT
WAS ADVERTISED 1-2 DAYS AGO. SO EXPECT ISOLATED SHOWERS THROUGH
THE MORNING HOURS...THEN SHOWER ACTIVITY SHOULD BECOME MORE
NUMEROUS ALONG THE NORTH BAY COAST BY MIDDAY AND CONTINUE TO
INCREASE THROUGH THE LATE AFTERNOON HOURS AS THE CORE OF THE LOW
APPROACHES THE BAY AREA. THE RAP MODEL IS THE MOST BULLISH FOR
PRECIP IN THE NORTH BAY WHILE THE NCEP SUITE OF MODELS KEEPS THE
BULK OF THE SHOWER ACTIVITY FROM ABOUT SANTA CRUZ SOUTHWARD.
HIGHER CONFIDENCE THAT THE MOST NUMEROUS SHOWER ACTIVITY WILL BE
FOCUSED OVER THE SOUTHERN REGIONS OF THE DISTRICT AS THE CORE OF
THE LOW WILL THEN DIVE SOUTHWARD DOWN THE COASTLINE. QPF TOTALS
WILL BE LIGHT WITH 0.10-0.25 ON AVERAGE. SINCE THE CORE OF THE LOW
STAYS OFF SHORE THE COLDEST AIR ALOFT WONT INFILTRATE THE
REGION...THUS SNOW LEVELS SHOULD GENERALLY STAY 3000 FEET AND
HIGHER. HAVE FINE TUNED THE INHERITED WINTER WX ADVISORY FOR THE
HIGHER TERRAIN OF MONTEREY AND SAN BENITO COUNTY TO DELAY THE
START AND SHORTEN THE END TIME TO THE PRE-DAWN HOURS OF TOMORROW.
THE MAIN PRECIP WILL WIND DOWN BY 12Z FRIDAY WITH JUST SOME
SCATTERED SHOWERS LEFT OVER ON FRIDAY MORNING FOR THE MONTEREY BAY
REGION...DECREASING TO ISOLATED BY FRIDAY AFTERNOON.
HIGH PRESSURE WILL BEGIN TO BUILD ON THE BACKSIDE OF THE TROUGH
WITH A CLEAR AND COLD MARCH NIGHT IN STORE FRIDAY NIGHT INTO
SATURDAY MORNING. HIGH PRESSURE RIDGE WILL NOSE IN SATURDAY
THROUGH THE WEEKEND AND INTO EARLY NEXT WEEK RESULTING IN DRY
WEATHER WITH TEMPERATURES CLIMBING TO NEAR OR ABOVE NORMAL BY
EARLY NEXT WEEK WITH MODERATING NIGHT TIME LOWS. LONG RANGE
FORECAST LOOKING DRY ONCE AGAIN. UNUSUAL PATTERN THE LAST SEVERAL
WEEKS WHERE WE GET ONE/TWO STORMS TO BREAK DOWN THE RIDGE BUT NO
SUSTAINED STORM CYCLES.
&&
.AVIATION...AS OF 10:05 AM PST THURSDAY...CURRENTLY THE VISIBLE
SATELLITE IMAGE IS SHOWING A LOW PRESSURE SYSTEM POSITIONED JUST
OFF OF THE SONOMA COAST. THIS LOW PRESSURE SYSTEM IS ADVECTING MID
TO UPPER LEVEL CLOUDS INTO THE MONTEREY AND SAN FRANCISCO BAY
AREAS. SHOWERS WILL BECOME A POSSIBILITY THIS AFTERNOON AND
EVENING AS THE LOW MOVE SOUTH ALONG THE COAST.
VICINITY OF KSFO...VFR IS FORECAST TODAY WITH SOUTH SOUTHEAST
WINDS. SHOWERS ARE EXPECTED BY 0000Z WITH LIGHT RAIN BY 0500Z.
NORTH WINDS WILL FILL INTO THE BAY AREA BY 1000Z.
KSFO BRIDGE APPROACH...SIMILAR TO KSFO.
MONTEREY BAY AREA TERMINALS...VFR IS FORECAST TODAY WITH SOUTHERLY WINDS.
SHOWERS WILL BE A POSSIBILITY BETWEEN 2100 AND 0000Z WITH LIGHT
RAIN BEGINNING AROUND 0000Z.
&&
.MTR WATCHES/WARNINGS/ADVISORIES...
.TDAY...WINTER WEATHER ADVISORY...ABOVE 3000 FEET IN MONTEREY
AND AND SAN BENITO COUNTY FROM 1 PM THURSDAY THROUGH 3 AM FRIDAY.
&&
$$
PUBLIC FORECAST: STROBIN/RWW
AVIATION/MARINE: LARRY
VISIT US AT WWW.WEATHER.GOV/SANFRANCISCO
FOLLOW US ON FACEBOOK, TWITTER, AND YOUTUBE AT:
WWW.FACEBOOK.COM/US.NATIONALWEATHERSERVICE.SANFRANCISCOBAYAREA.GOV
WWW.TWITTER.COM/NWSBAYAREA
WWW.YOUTUBE.COM/NWSBAYAREA
AREA FORECAST DISCUSSION
NWS SAN FRANCISCO BAY AREA
920 AM PST THU MAR 7 2013
.DISCUSSION...AS OF 9:10 AM PST THURSDAY...SATL IMAGERY IS INDC
THAT THE UPPER LOW IS WEST OF PT REYES AND IS SLOWLY MOVING
SOUTH...BUT WILL REMAIN OFF THE COAST. SO FAR...RADAR AND SFC OBS
ARE SHOWING ALL RAIN OFF THE COAST.
WITH THE TRACK OF THE UPPER LOW FCST TO BE WEST OF THE COAST...
THE CORE OF THE COLD AIR WILL REMAIN OVER THE OCEAN. THE QUESTION
THEN BECOMES WHAT TO DO WITH THE WINTER WEATHER ADVISORIES THAT
ARE CURRENTLY OUT FOR THE SOUTHERN MOUNTAINS. BASED ON THE LATEST
MODEL DATA IT APPEARS THAT THE SNOW LEVELS MIGHT BE HIGHER THAN
PREVIOUSLY EXPECTED. HOWEVER...ANY CONVECTIVE SHOWERS COULD DROP
THE SNOW LEVELS DOWN TEMPORARILY. BOTTOM LINE IS THAT THERE WAS
CONSIDERATION FOR DROPPING THE WINTER WEATHER ADVISORIES...HAVE
DECIDED TO LET THEM CONTINUE DUE TO THE POSSIBILITY OF CONVECTIVE
ACTIVITY DROPPING THE SNOW LEVELS LOW ENOUGH TO GET A QUICK COUPLE
OF INCHES OR MORE.
CURRENT FORECAST ON TRACK...NO UPDATES.
PREVIOUS DISCUSSION...AS OF 3:37 AM PST THURSDAY...FORECAST
FOCUS IS ON SHORTWAVE CURRENTLY LOCATED JUST WEST OF CAPE
MENDOCINO. COMPARED TO 24 HOURS AGO THE MODELS ARE NOW BRINGING
THE MAIN CORE OF THE LOW CLOSER TO THE BAY AREA LATER THIS
AFTERNOON AND EVENING...WHEREAS EARLIER RUNS WERE KEEPING THE BULK
OF THE ENERGY AND ASSOCIATED MOISTURE OFFSHORE AND THEN TOWARDS
SOUTHERN CALIFORNIA. LATEST SOLUTIONS ARE MORE IN-LINE WITH WHAT
WAS ADVERTISED 1-2 DAYS AGO. SO EXPECT ISOLATED SHOWERS THROUGH
THE MORNING HOURS...THEN SHOWER ACTIVITY SHOULD BECOME MORE
NUMEROUS ALONG THE NORTH BAY COAST BY MIDDAY AND CONTINUE TO
INCREASE THROUGH THE LATE AFTERNOON HOURS AS THE CORE OF THE LOW
APPROACHES THE BAY AREA. THE RAP MODEL IS THE MOST BULLISH FOR
PRECIP IN THE NORTH BAY WHILE THE NCEP SUITE OF MODELS KEEPS THE
BULK OF THE SHOWER ACTIVITY FROM ABOUT SANTA CRUZ SOUTHWARD.
HIGHER CONFIDENCE THAT THE MOST NUMEROUS SHOWER ACTIVITY WILL BE
FOCUSED OVER THE SOUTHERN REGIONS OF THE DISTRICT AS THE CORE OF
THE LOW WILL THEN DIVE SOUTHWARD DOWN THE COASTLINE. QPF TOTALS
WILL BE LIGHT WITH 0.10-0.25 ON AVERAGE. SINCE THE CORE OF THE LOW
STAYS OFF SHORE THE COLDEST AIR ALOFT WONT INFILTRATE THE
REGION...THUS SNOW LEVELS SHOULD GENERALLY STAY 3000 FEET AND
HIGHER. HAVE FINE TUNED THE INHERITED WINTER WX ADVISORY FOR THE
HIGHER TERRAIN OF MONTEREY AND SAN BENITO COUNTY TO DELAY THE
START AND SHORTEN THE END TIME TO THE PRE-DAWN HOURS OF TOMORROW.
THE MAIN PRECIP WILL WIND DOWN BY 12Z FRIDAY WITH JUST SOME
SCATTERED SHOWERS LEFT OVER ON FRIDAY MORNING FOR THE MONTEREY BAY
REGION...DECREASING TO ISOLATED BY FRIDAY AFTERNOON.
HIGH PRESSURE WILL BEGIN TO BUILD ON THE BACKSIDE OF THE TROUGH
WITH A CLEAR AND COLD MARCH NIGHT IN STORE FRIDAY NIGHT INTO
SATURDAY MORNING. HIGH PRESSURE RIDGE WILL NOSE IN SATURDAY
THROUGH THE WEEKEND AND INTO EARLY NEXT WEEK RESULTING IN DRY
WEATHER WITH TEMPERATURES CLIMBING TO NEAR OR ABOVE NORMAL BY
EARLY NEXT WEEK WITH MODERATING NIGHT TIME LOWS. LONG RANGE
FORECAST LOOKING DRY ONCE AGAIN. UNUSUAL PATTERN THE LAST SEVERAL
WEEKS WHERE WE GET ONE/TWO STORMS TO BREAK DOWN THE RIDGE BUT NO
SUSTAINED STORM CYCLES.
&&
.AVIATION...AS OF 3:50 AM PST THURSDAY...A STORM SYSTEM IS
FORECAST TO MOVE TOWARD THE REGION LATER THIS MORNING. THIS STORM
WILL BRING RAIN SHOWERS TO THE TERMINALS...MAINLY IMPACTING KSJC
SOUTHWARD. MAINLY LIGHT AND VARIABLE WINDS ALONG WITH VFR CIGS
WILL ACCOMPANY THIS STORM. SHOWER ACTIVITY WILL SUBSIDE THIS
EVENING INTO THE OVERNIGHT HOURS.
VICINITY OF KSFO...VFR CONDITIONS WILL PREVAIL THROUGH THE
FORECAST. RAIN SHOWERS ARE FORECAST TO IMPACT THE BAY BY
17Z...WITH A STRAY SHOWER POSSIBLE BEFORE THIS TIME. LIGHT
SOUTHERLY WINDS WILL BECOME WESTERLY BY THIS AFTERNOON. RAIN
SHOWER ACTIVITY WILL MOVE OUT OF THE REGION BY 10Z FRIDAY.
KSFO BRIDGE APPROACH...SIMILAR TO KSFO.
MONTEREY BAY AREA TERMINALS...VFR CONDITIONS WILL PREVAIL THROUGH
THE FORECAST. RAIN SHOWER ACTIVITY WILL INCREASE EARLY THIS
AFTERNOON AND CONTINUE THROUGH THE OVERNIGHT HOURS.
&&
.MTR WATCHES/WARNINGS/ADVISORIES...
.TDAY...WINTER WEATHER ADVISORY...ABOVE 3000 FEET IN MONTEREY AND
AND SAN BENITO COUNTY FROM 1 PM TODAY THROUGH 3 AM FRIDAY.
&&
$$
PUBLIC FORECAST: STROBIN/RWW
AVIATION/MARINE: LARRY/RILEY
VISIT US AT WWW.WEATHER.GOV/SANFRANCISCO
FOLLOW US ON FACEBOOK, TWITTER, AND YOUTUBE AT:
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WWW.TWITTER.COM/NWSBAYAREA
WWW.YOUTUBE.COM/NWSBAYAREA
AREA FORECAST DISCUSSION
NWS SAN FRANCISCO BAY AREA
351 AM PST THU MAR 7 2013
.DISCUSSION...AS OF 3:37 AM PST THURSDAY...FORECAST FOCUS IS ON
SHORTWAVE CURRENTLY LOCATED JUST WEST OF CAPE MENDOCINO. COMPARED
TO 24 HOURS AGO THE MODELS ARE NOW BRINGING THE MAIN CORE OF THE
LOW CLOSER TO THE BAY AREA LATER THIS AFTERNOON AND
EVENING...WHEREAS EARLIER RUNS WERE KEEPING THE BULK OF THE ENERGY
AND ASSOCIATED MOISTURE OFFSHORE AND THEN TOWARDS SOUTHERN
CALIFORNIA. LATEST SOLUTIONS ARE MORE IN-LINE WITH WHAT WAS
ADVERTISED 1-2 DAYS AGO. SO EXPECT ISOLATED SHOWERS THROUGH THE
MORNING HOURS...THEN SHOWER ACTIVITY SHOULD BECOME MORE NUMEROUS
ALONG THE NORTH BAY COAST BY MIDDAY AND CONTINUE TO INCREASE
THROUGH THE LATE AFTERNOON HOURS AS THE CORE OF THE LOW APPROACHES
THE BAY AREA. THE RAP MODEL IS THE MOST BULLISH FOR PRECIP IN THE
NORTH BAY WHILE THE NCEP SUITE OF MODELS KEEPS THE BULK OF THE
SHOWER ACTIVITY FROM ABOUT SANTA CRUZ SOUTHWARD. HIGHER CONFIDENCE
THAT THE MOST NUMEROUS SHOWER ACTIVITY WILL BE FOCUSED OVER THE
SOUTHERN REGIONS OF THE DISTRICT AS THE CORE OF THE LOW WILL THEN
DIVE SOUTHWARD DOWN THE COASTLINE. QPF TOTALS WILL BE LIGHT WITH
0.10-0.25 ON AVERAGE. SINCE THE CORE OF THE LOW STAYS OFF SHORE
THE COLDEST AIR ALOFT WONT INFILTRATE THE REGION...THUS SNOW
LEVELS SHOULD GENERALLY STAY 3000 FEET AND HIGHER. HAVE FINE TUNED
THE INHERITED WINTER WX ADVISORY FOR THE HIGHER TERRAIN OF
MONTEREY AND SAN BENITO COUNTY TO DELAY THE START AND SHORTEN THE
END TIME TO THE PRE-DAWN HOURS OF TOMORROW. THE MAIN PRECIP WILL
WIND DOWN BY 12Z FRIDAY WITH JUST SOME SCATTERED SHOWERS LEFT OVER
ON FRIDAY MORNING FOR THE MONTEREY BAY REGION...DECREASING TO
ISOLATED BY FRIDAY AFTERNOON.
HIGH PRESSURE WILL BEGIN TO BUILD ON THE BACKSIDE OF THE TROUGH
WITH A CLEAR AND COLD MARCH NIGHT IN STORE FRIDAY NIGHT INTO
SATURDAY MORNING. HIGH PRESSURE RIDGE WILL NOSE IN SATURDAY
THROUGH THE WEEKEND AND INTO EARLY NEXT WEEK RESULTING IN DRY
WEATHER WITH TEMPERATURES CLIMBING TO NEAR OR ABOVE NORMAL BY
EARLY NEXT WEEK WITH MODERATING NIGHT TIME LOWS. LONG RANGE
FORECAST LOOKING DRY ONCE AGAIN. UNUSUAL PATTERN THE LAST SEVERAL
WEEKS WHERE WE GET ONE/TWO STORMS TO BREAK DOWN THE RIDGE BUT NO
SUSTAINED STORM CYCLES.
&&
.AVIATION...AS OF 3:50 AM PST THURSDAY...A STORM SYSTEM IS
FORECAST TO MOVE TOWARD THE REGION LATER THIS MORNING. THIS STORM
WILL BRING RAIN SHOWERS TO THE TERMINALS...MAINLY IMPACTING KSJC
SOUTHWARD. MAINLY LIGHT AND VARIABLE WINDS ALONG WITH VFR CIGS
WILL ACCOMPANY THIS STORM. SHOWER ACTIVITY WILL SUBSIDE THIS
EVENING INTO THE OVERNIGHT HOURS.
VICINITY OF KSFO...VFR CONDITIONS WILL PREVAIL THROUGH THE
FORECAST. RAIN SHOWERS ARE FORECAST TO IMPACT THE BAY BY
17Z...WITH A STRAY SHOWER POSSIBLE BEFORE THIS TIME. LIGHT
SOUTHERLY WINDS WILL BECOME WESTERLY BY THIS AFTERNOON. RAIN
SHOWER ACTIVITY WILL MOVE OUT OF THE REGION BY 10Z FRIDAY.
KSFO BRIDGE APPROACH...SIMILAR TO KSFO.
MONTEREY BAY AREA TERMINALS...VFR CONDITIONS WILL PREVAIL THROUGH
THE FORECAST. RAIN SHOWER ACTIVITY WILL INCREASE EARLY THIS
AFTERNOON AND CONTINUE THROUGH THE OVERNIGHT HOURS.
&&
.MTR WATCHES/WARNINGS/ADVISORIES...
.TDAY...WINTER WEATHER ADVISORY...ABOVE 3000 FEET IN MONTEREY AND
AND SAN BENITO COUNTY FROM 1 PM THURSDAY THROUGH 3 AM FRIDAY.
&&
$$
PUBLIC FORECAST: RWW
AVIATION/MARINE: RILEY
VISIT US AT WWW.WEATHER.GOV/SANFRANCISCO
FOLLOW US ON FACEBOOK, TWITTER, AND YOUTUBE AT:
WWW.FACEBOOK.COM/US.NATIONALWEATHERSERVICE.SANFRANCISCOBAYAREA.GOV
WWW.TWITTER.COM/NWSBAYAREA
WWW.YOUTUBE.COM/NWSBAYAREA
AREA FORECAST DISCUSSION
NWS SAN FRANCISCO BAY AREA
337 AM PST THU MAR 7 2013
.DISCUSSION...AS OF 3:37 AM PST THURSDAY...FORECAST FOCUS IS ON
SHORTWAVE CURRENTLY LOCATED JUST WEST OF CAPE MENDOCINO. COMPARED
TO 24 HOURS AGO THE MODELS ARE NOW BRINGING THE MAIN CORE OF THE
LOW CLOSER TO THE BAY AREA LATER THIS AFTERNOON AND
EVENING...WHEREAS EARLIER RUNS WERE KEEPING THE BULK OF THE ENERGY
AND ASSOCIATED MOISTURE OFFSHORE AND THEN TOWARDS SOUTHERN
CALIFORNIA. LATEST SOLUTIONS ARE MORE IN-LINE WITH WHAT WAS
ADVERTISED 1-2 DAYS AGO. SO EXPECT ISOLATED SHOWERS THROUGH THE
MORNING HOURS...THEN SHOWER ACTIVITY SHOULD BECOME MORE NUMEROUS
ALONG THE NORTH BAY COAST BY MIDDAY AND CONTINUE TO INCREASE
THROUGH THE LATE AFTERNOON HOURS AS THE CORE OF THE LOW APPROACHES
THE BAY AREA. THE RAP MODEL IS THE MOST BULLISH FOR PRECIP IN THE
NORTH BAY WHILE THE NCEP SUITE OF MODELS KEEPS THE BULK OF THE
SHOWER ACTIVITY FROM ABOUT SANTA CRUZ SOUTHWARD. HIGHER CONFIDENCE
THAT THE MOST NUMEROUS SHOWER ACTIVITY WILL BE FOCUSED OVER THE
SOUTHERN REGIONS OF THE DISTRICT AS THE CORE OF THE LOW WILL THEN
DIVE SOUTHWARD DOWN THE COASTLINE. QPF TOTALS WILL BE LIGHT WITH
0.10-0.25 ON AVERAGE. SINCE THE CORE OF THE LOW STAYS OFF SHORE
THE COLDEST AIR ALOFT WONT INFILTRATE THE REGION...THUS SNOW
LEVELS SHOULD GENERALLY STAY 3000 FEET AND HIGHER. HAVE FINE TUNED
THE INHERITED WINTER WX ADVISORY FOR THE HIGHER TERRAIN OF
MONTEREY AND SAN BENITO COUNTY TO DELAY THE START AND SHORTEN THE
END TIME TO THE PRE-DAWN HOURS OF TOMORROW. THE MAIN PRECIP WILL
WIND DOWN BY 12Z FRIDAY WITH JUST SOME SCATTERED SHOWERS LEFT OVER
ON FRIDAY MORNING FOR THE MONTEREY BAY REGION...DECREASING TO
ISOLATED BY FRIDAY AFTERNOON.
HIGH PRESSURE WILL BEGIN TO BUILD ON THE BACKSIDE OF THE TROUGH
WITH A CLEAR AND COLD MARCH NIGHT IN STORE FRIDAY NIGHT INTO
SATURDAY MORNING. HIGH PRESSURE RIDGE WILL NOSE IN SATURDAY
THROUGH THE WEEKEND AND INTO EARLY NEXT WEEK RESULTING IN DRY
WEATHER WITH TEMPERATURES CLIMBING TO NEAR OR ABOVE NORMAL BY
EARLY NEXT WEEK WITH MODERATING NIGHT TIME LOWS. LONG RANGE
FORECAST LOOKING DRY ONCE AGAIN. UNUSUAL PATTERN THE LAST SEVERAL
WEEKS WHERE WE GET ONE/TWO STORMS TO BREAK DOWN THE RIDGE BUT NO
SUSTAINED STORM CYCLES.
&&
.AVIATION...AS OF 9:30 PM PST WEDNESDAY...SOME HIGH CLOUDS WERE
STILL STREAMING OVER THE AREA ASSOCIATED WITH A JET STREAK EXITING
TO THE EAST. INCREASING STABILITY TONIGHT MAY LEAD TO A FEW FOG
PATCHES INLAND VALLEYS VERY LATE TONIGHT WHERE MOSTLY CLEAR SKIES
PREVAIL. BEST CHANCES FOR RADIATIONAL COOLING WILL BE OVER THE
NORTHERN HALF OF THE AREA WHERE SUBSIDENCE PREVAILS TONIGHT.
A MUCH COLDER UPPER LOW WILL MOVE SOUTH OVER THE COASTAL WATERS
THURSDAY BRINGING SHOWERS BACK INTO THE PICTURE THURSDAY AND
THURSDAY NIGHT. A SLIGHT INCREASE IN INSTABILITY PARAMETERS SUGGESTS
POSSIBLE ISOLATED THUNDER AFTER 21Z PER CHECK ON MODIFIED FORECAST
SOUNDINGS. INSTABILITY GRADUALLY DECLINES THURSDAY NIGHT AS THE
CORE OF THE COLDEST AIR SHIFTS WEST AND THEN SOUTH OF THE AREA
REACHING SOCAL FRIDAY MORNING.
VICINITY OF KSFO...VFR. LIGHT WINDS. DRY RUNWAYS ARE EXPECTED TIL
INSTABILITY/POSSIBLE SHOWER ACTIVITY ARRIVES THURSDAY AFTERNOON
AND EVENING.
KSFO BRIDGE APPROACH...VFR. AREA WEATHER PATTERN IS NOT VERY
FAVORABLE FOR FOG PATCHES. IF ANY DO DEVELOP THURSDAY MORNING
THEY SHOULD QUICKLY MIX OUT AFTER SUNRISE.
MONTEREY BAY AREA TERMINALS...HIGH CLOUDS CONTINUE TO STREAM IN
FROM THE WSW. VFR. BEST CHANCES FOR WET WEATHER ARRIVES BY LATE
THURSDAY MORNING OR EARLY AFTERNOON.
&&
.MTR WATCHES/WARNINGS/ADVISORIES...
.TDAY...WINTER WEATHER ADVISORY...ABOVE 3000 FEET IN MONTEREY AND
AND SAN BENITO COUNTY FROM 1 PM THURSDAY THROUGH 3 AM FRIDAY.
&&
$$
PUBLIC FORECAST: RWW
AVIATION/MARINE: CANEPA
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AREA FORECAST DISCUSSION
NWS TAMPA BAY RUSKIN FL
245 AM EST THU MAR 7 2013
...DRY WEATHER AND SLOWLY WARMING TEMPS THE NEXT SEVERAL DAYS...
.SYNOPSIS...
07Z WATER VAPOR AND H4 RAP ANALYSIS SHOW THAT MUCH OF THE COUNTY IS
NOW BENEATH A BROAD LONGWAVE RIDGE EXTENDING FROM THE THE
CONTINENTAL DIVIDE EASTWARD TO THE UPPER MIDWEST/TN VALLEY. ON
EITHER SIDE OF THIS RIDGE WE FIND TROUGHING IN PLACE OVER THE
PACIFIC/NORTHWEST...AND ALSO TROUGHING/CLOSED UPPER LOW EXITING THE
MID-ATLANTIC TOWARD THE NORTHEASTERN STATES. OUR FORECAST AREA
RESIDES WITHIN A ZONE OF DEEP NW FLOW BETWEEN THE DEPARTING TROUGH
AND THE CENTRAL CONUS RIDGE. REGIONAL SOUNDING FROM THIS PAST
EVENING CONFIRM THE WATER VAPOR PRESENTATION THAT THE COLUMN OVER
THE FL PENINSULA IS EXTREMELY DRY. PW VALUES WERE GENERALLY WELL
UNDER HALF THE CLIMO VALUES FOR EARLY MARCH. THIS DRY AIR ALONG WITH
VIRTUALLY NO SYNOPTIC SUPPORT FOR LIFT IS RESULTING IN CLEAR SKIES
EARLY THIS MORNING.
AT THE SURFACE...WEDNESDAYS COLD FRONT IS NOW WELL SOUTH OF THE
PENINSULA WITH HIGH PRESSURE CENTERED ALONG THE MS VALLEY TRYING TO
RIDGE IN FROM THE NW. TEMPERATURES ARE COOL AS THE DRY ATMOSPHERE
HELPS WITH THE RADIATIVE PROCESS...HOWEVER THE GRADIENT IS TIGHT
ENOUGH SO FAR TO PREVENT MUCH IN THE WAY OF BOUNDARY LAYER
DE-COUPLING...EVEN UP NORTH. THIS LACK OF DE-COUPLING SHOULD
GENERALLY HELP KEEP TEMPS UP AND PREVENT MUCH FROST. IT IS STILL
POSSIBLE WITH THE RIDGE BUILDING THAT A BRIEF DECOUPLING COULD OCCUR
FOR OUR NORTHERN NATURE COAST ZONES TOWARD DAWN...ALLOWING A SHOT AT
BRIEFLY DROPPING DOWN TOWARD FREEZING.
&&
.SHORT TERM (TODAY THROUGH SATURDAY)...
TODAY/TONIGHT...
QUIET...DRY AND COOL PERIOD THE NEXT 24-30 HOURS WITH TEMPERATURES
BELOW NORMAL FOR EARLY MARCH. FORECAST AREA WILL REMAIN EMBEDDED
WITHIN A DEEP LAYER NW FLOW PATTERN ON THE EASTERN PERIPHERY OF A
BUILDING/AMPLIFYING UPPER RIDGE. LOOKING FOR GENERALLY ABUNDANT
SUNSHINE TODAY...ESPECIALLY DURING THE MORNING HOURS. DURING THE
AFTERNOON AND EVENING WE MAY SEE SOME SCT HIGH LEVEL CIRRUS TO
FILTER THE SUN ARRIVING AS A WEAK UPPER LEVEL SHORTWAVE...NOW SEEN
IN WV IMAGE OVER THE LOWER MS VALLEY...TRACKS SOUTHEASTWARD TOWARD
THE REGION. THIS WEAK IMPULSE WILL EXIT TO OUR EAST LATE
TONIGHT/EARLY FRIDAY WITH ANY HIGH CIRRUS FOLLOWING INTO THE
ATLANTIC. HIGH TEMPS TODAY WILL REACH THE MID/UPPER 60S NORTH OF I-4
AND GENERALLY LOWER 70S FURTHER SOUTH. SOME AFTERNOON ONSHORE WIND
COMPONENT NEAR THE COAST IS LIKELY TO KEEP READINGS A FEW DEGREES
COOLER AT THE BEACHES...ESPECIALLY FROM MANATEE COUNTY NORTHWARD. A
DRY ATMOSPHERE AND SURFACE RIDGING STILL BUILDING IN FROM THE NORTH
WILL ALLOW FOR ANOTHER COOL OVERNIGHT PERIOD. ENOUGH RIDGING IS
LIKELY INTO THE NATURE COAST TO ALLOW FOR A POTENTIAL BRIEF
DECOUPLING TOWARD DAWN. THEREFORE A FEW NORMALLY COLDER SPOTS FROM
BROOKSVILLE NORTH MAY APPROACH FREEZING. SMALL DEWPOINT DEPRESSION
AND LIGHT WINDS BY THIS TIME SUGGEST FOR SOME PATCHY FROST
FORMATION. HAVE ADDED THIS POTENTIAL TO THE FORECAST GRIDS FOR
LOCATIONS FORECAST TO REACH 35 DEGREES OR LOWER. PATCHY FROST WILL
ALSO BE POSSIBLE FOR THE NORMALLY COLDER SPOTS WITHIN
HARDEE/DESOTO/HIGHLANDS COUNTIES...ALTHOUGH THESE AREAS ARE MORE
CONDITIONAL ON THE OCCURRENCE OF TRUE BOUNDARY LAYER DECOUPLING.
FRIDAY THROUGH SATURDAY...
VERY PLEASANT AND SEASONABLE CONDITIONS TO END THE WEEK WITH
TEMPERATURES RETURNING TO NORMAL...OR EVEN SLIGHTLY ABOVE NORMAL
DAYTIME READING BY SATURDAY AFTERNOON.
IMPRESSIVE MID/UPPER LEVEL RIDGE WILL CONTINUE TO AMPLIFY AND BUILD
EAST OVER-TOP THE FORECAST AREA. THIS STACKED RIDGING COMBINED WITH
THE SURFACE HIGH STILL RIDGING IN FROM THE NORTH WILL KEEP OUR AREA
PROTECTED WITH NEAR ZERO CHANCE OF RAIN INTO THE WEEKEND. HIGH TEMPS
WILL REBOUND NICELY ON FRIDAY AFTER THE COOL EARLY MORNING START.
SOME LOCATIONS MAY SEE A 35-40 DEGREE DIURNAL SWING. CURRENTLY
EXPECTING LOWER 70S NORTH AND MIDDLE 70S SOUTH. ONCE AGAIN...THE
POTENTIAL FOR A WEAK ONSHORE COMPONENT TO THE WIND DEVELOPING FOR
THE AFTERNOON MAY KEEP THE BEACHES A FEW DEGREES COOLER. LOW TEMPS
FRIDAY NIGHT WILL STILL BE COOL...BUT DO NOT ANTICIPATE ANY CHANCE
OF FREEZING TEMPS OR EVEN ANY FROST AS READING WARM 5-10 DEGREES
FROM THURSDAY NIGHT LOWS. HIGH TEMPERATURES SATURDAY WILL RESPOND TO
THIS LESS CHILLY START...AND THE MAXIMIZED HEIGHT
FIELDS/SUPPRESSION...TO EASILY REACH THE MIDDLE 70S NORTH AND
NEAR 80 IN THE SOUTH. LOW LEVEL SURFACE RIDGE TAKES A POSITION TO
OUR NORTH/NORTHEAST ON SATURDAY RESULTING IN STRONGER EASTERLY FLOW.
975-925MB BOUNDARY LAYER WINDS ARE FORECAST TO BE STRAIGHT EAST AT
10-15 KNOTS. 10-15 KNOTS SHOULD BE ENOUGH (GIVEN THE DEGREE OF
TERRESTRIAL WARMING) TO PREVENT ANY SEA-BREEZE CIRCULATION FROM
MOVING ONSHORE...AND ALLOW WARMER BEACH TEMPS THAN PREVIOUS DAYS.
ENJOY!
&&
.LONG TERM (SUNDAY THROUGH NEXT WEDNESDAY)...
DEEP LAYER RIDGING FROM THE GULF TO THE LOWER GREAT LAKES SAT NIGHT
SLOWLY TREKS EASTWARD...SLIDING OFF THE EASTERN SEABOARD MON. THIS
PROVIDES A DRY AIR MASS WITH INITIALLY NEAR NORMAL TEMPERATURES THAT
WARM SLIGHTLY. NORTH AND NE WINDS VEER TO SOUTHERLY BY MON AND MAY
BECOME ROBUST ON THE GULF AT TIMES.
FOR TUE AND WED...AN UPPER LEVEL LONG WAVE TROUGH WITH AN ATTENDANT
FRONTAL BOUNDARY MOVES INTO THE GULF-GREAT LAKES REGION THEN SHIFTS
OUT OVER THE ATLANTIC WED...SWEEPING THE FRONTAL BOUNDARY ACROSS THE
STATE MAINLY DURING THE DAY TUE. THE PORTION OF THE BOUNDARY MOVING
OVER THE AREA APPEARS RATHER WEAK AND WILL LIMIT PRECIPITATION TO
JUST SLIGHT CHANCE OF SHOWERS. WINDS SHIFT TO NORTHERLY IN THE WAKE
OF THE FRONT AND ARE EXPECT TO STAY BELOW ADVISORY SPEEDS.
TEMPERATURES COOL SLIGHT BUT STAY CLOSE TO NORMAL.
&&
.MARINE...
CAUTIONARY LEVEL NORTHERLY WINDS AWAY FROM THE SHORE WILL DIMINISH
BELOW 15 KNOTS BY MIDDAY. DUE TO RESIDUAL WAVE ACTION OBSERVED AT
REGIONAL BUOYS EARLY THIS MORNING...HAVE EXTENDED THE SMALL CRAFT
ADVISORY UNTIL MID-MORNING FOR THE OFFSHORE LEGS FROM BONITA BEACH
TO TARPON SPRINGS. ALL HEADLINES SHOULD THEN BE DROPPED FOR THE
AFTERNOON HOURS. BELOW HEADLINE CRITERIA WINDS AND SEAS ARE FORECAST
ACROSS THE EASTERN GULF THROUGH FRIDAY AFTERNOON AS HIGH PRESSURE
RIDGES IN FROM THE NORTH. THIS RIDGE WILL THEN TAKE UP A POSITION
FRIDAY NIGHT INTO EARLY SUNDAY THAT WILL BE FAVORABLE FOR THE
DEVELOPMENT OF NOCTURNAL/EARLY MORNING EASTERLY WINDS SURGES. THE
FORECAST WILL REFLECT THIS POTENTIAL WITH NEAR CAUTIONARY LEVEL
WINDS FRIDAY NIGHT. WINDS WILL DIMINISH FOR MUCH OF THE DAYLIGHT
HOURS OF SATURDAY...ONLY TO BUILD TO SOLID CAUTIONARY LEVELS LATER
SATURDAY EVENING AND NIGHT.
&&
.AVIATION...
VFR CONDITIONS FOR THE NEXT 24 HOURS WITH AFTERNOON CIRRUS. WINDS
NORTHEAST-NORTHWEST AT 10KT OR LESS.
&&
.FIRE WEATHER...
AN EXTENDED PERIOD OF CRITICALLY LOW RELATIVE HUMIDITY AWAY FROM THE
COAST IS EXPECTED FROM LATE THIS MORNING THROUGH THE EARLY EVENING
HOURS. ERC VALUES ARE ABOVE 37 FOR PINELLAS AND POLK
TODAY...HOWEVER ONLY POLK IS EXPECTED TO SEE THE CRITICAL DURATIONS
COINCIDENT WITH THE HIGH ERC. A RED FLAG WARNING HAS BEEN ISSUED FOR
POLK FOR THESE REASONS. ANOTHER DAY OF EXTENDED CRITICALLY LOW
RELATIVE HUMIDITY IS ANTICIPATED ON FRIDAY. THE POTENTIAL FOR ZONES
TO THAT ARE JUST UNDER ERC VALUES OF 37 TODAY TO RISE A FEW DIGITS
ON FRIDAY...HAS PROMPTED THE ISSUANCE OF A FIRE WEATHER WATCH FOR
POLK...PINELLAS... HIGHLANDS...AND LEE COUNTIES FRIDAY AFTERNOON.
&&
.PRELIMINARY POINT TEMPS/POPS...
TPA 65 47 72 51 / 0 0 0 0
FMY 71 47 76 53 / 0 0 0 0
GIF 69 42 75 49 / 0 0 0 0
SRQ 66 45 72 52 / 0 0 0 0
BKV 67 34 71 42 / 0 0 0 0
SPG 65 50 72 57 / 0 0 0 0
&&
.TBW WATCHES/WARNINGS/ADVISORIES...
FL...BEACH HAZARDS STATEMENT UNTIL NOON EST TODAY FOR CHARLOTTE-
HILLSBOROUGH-LEE-MANATEE-PINELLAS-SARASOTA.
FIRE WEATHER WATCH FROM FRIDAY MORNING THROUGH FRIDAY
AFTERNOON FOR HIGHLANDS-LEE-PINELLAS-POLK.
RED FLAG WARNING FROM 11 AM THIS MORNING TO 7 PM EST THIS
EVENING FOR POLK.
GULF WATERS...SMALL CRAFT ADVISORY UNTIL 11 AM EST THIS MORNING FOR
BONITA BEACH TO ENGLEWOOD OUT 20 TO 60 NM-ENGLEWOOD
TO TARPON SPRINGS OUT 20 TO 60 NM.
&&
$$
SYNOPSIS/SHORT TERM/MARINE/FIRE WX...MROCZKA
LONG TERM/AVIATION...RUDE
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
947 PM CST FRI MAR 8 2013
.DISCUSSION...
924 PM CST
NO REAL BIG CHANGES TO GOING FORECAST TONIGHT...WITH ONLY MINOR
EDITS TO POP/WX FOR AREAS ACROSS NORTHWEST ILLINOIS.
LATEST SATELLITE IMAGERY DEPICTING MID/UPPER LEVEL CLOUD COVER
CONTINUING TO STREAM NORTHEAST ACROSS THE REGION THIS EVENING...AS
SOUTHWESTERLY FLOW CONTINUES OUT AHEAD OF AN APPROACHING LONGWAVE
TROUGH OVER THE WESTERN CONUS. THIS IS USHERING IN A WARMER AND
MORE MOIST ENVIRONMENT WITH LATEST RAP ANALYSIS DEPICTING STRONG
WAA OCCURRING ACROSS MUCH OF THE PLAINS...AND CAN BE NOTED VIA THE
ABUNDANCE OF CLOUD COVER AS WELL AS THE WIDESPREAD PRECIP SHIELD
IN THIS LOCATION. ALTHOUGH THE STRONGEST WAA WILL REMAIN JUST TO
THE WEST OF THE CWA...LATEST SHORT TERM GUIDANCE IS INDICATING
THAT SOME LIGHT PRECIP DEVELOPMENT COULD OCCUR ACROSS NORTHWEST
ILLINOIS TONIGHT AS THIS WAA WING CONTINUES TO LIFT
NORTH/NORTHEAST. PRECIP DEVELOPMENT LATE TONIGHT ACROSS AREAS
ALONG AND WEST OF INTERSTATE 39 DOES SEEM REASONABLE WITH THIS
BETTER FORCING ALREADY INCHING CLOSER TO THE CWA. ALTHOUGH THIS
FORCING WILL REMAIN RATHER WEAK...IT MAY BE ENOUGH OF A PERSISTENT
FEATURE TO OVERCOME SOME DRIER AIR IN PLACE. THERMAL PROFILES WILL
SUPPORT PRECIP OF THE LIQUID TYPE...BUT WITH THE POSSIBILITY OF A
BRIEF WINDOW OF LIGHT FREEZING RAIN. ALTHOUGH...WARMING TONIGHT
SHOULD MITIGATE ANY OVERALL FREEZING RAIN POTENTIAL WITH SURFACE
TEMPERATURES EXPECTED TO BE HOVERING AROUND FREEZING IF NOT
BEGINNING TO RISE JUST ABOVE BY THE TIME THIS PRECIP ARRIVES. SO
HAVE MADE MENTION OF A SLIGHT CHANCE OF LIGHT RAIN/LIGHT FREEZING
RAIN FOR LATE TONIGHT INTO EARLY SATURDAY MORNING BEFORE
TEMPERATURES CONTINUE TO RISE THROUGH MID SATURDAY MORNING WITH
ONLY RAIN THEN EXPECTED.
RODRIGUEZ
&&
.PREV DISCUSSION...
234 PM CST
THE AREA WILL QUICKLY SHIFT FROM WINTER TO SPRING WEATHER THIS
WEEKEND WITH EXPECTED RAINFALL/SNOW MELT WITH WARMING TEMPERATURES
POSING A FLOOD THREAT...WITH THUNDERSTORMS NOT OUT OF THE QUESTION
BY SUNDAY. UPS AND DOWNS IN TEMPERATURES ARE EXPECTED NEXT WEEK WITH
A SERIES OF WEAKER SYSTEMS BRINGING PERIODIC LOW CHANCES FOR
PRECIPITATION.
SYNOPSIS...EARLY AFTERNOON WATER VAPOR IMAGERY SHOWS UPPER RIDGING
BUILDING ACROSS THE MISSISSIPPI RIVER VALLEY INTO THE LOCAL AREA IN
RESPONSE TO A DEEP CLOSED UPPER LOW ROTATING INTO THE DESERT
SOUTHWEST. THIS TROUGH IS SPLIT FROM A TROUGH THAT IS POSITIONED
OVER CENTRAL CANADA WITH A TROUGH AXIS SHIFTING TOWARDS WESTERN
SASKATCHEWAN. THESE TWO FEATURES WILL BE THE MAIN DRIVERS OF
EXPECTED RAINFALL THIS WEEKEND. AT THE SURFACE...A LARGE AREA OF
HIGH PRESSURE IS EXITING THE LOCAL AREA TO THE EAST. WEAK LOW
PRESSURE IS OVER SOUTHERN MANITOBA AND IS DRIFTING EASTWARD.
TONIGHT AND SATURDAY...QUIET WEATHER WILL CONTINUE TONIGHT WITH THE
UPPER RIDGE CRESTING THE AREA THIS EVENING. THE BIG SOUTHWEST
TROUGH WILL BE MOVING EASTWARD WITH HEIGHT FALLS AHEAD OF IT AND
BEHIND THE RIDGE ALLOWING LOW PRESSURE TO DEVELOP IN THE LEE OF
THE ROCKIES. A 50+KT LOW LEVEL JET WILL SET UP ACROSS THE PLAINS
RESULTING IN A STRONG PUSH OF HIGH THETA-E LOW LEVEL AIR ACROSS
THE SOUTHERN AND CENTRAL PLAINS. HIGH LEVEL MOISTURE WILL BE
SPREAD NORTHEASTWARD SUPPORTING AN INCREASE IN MID AND HIGH LEVEL
CLOUD COVER OVERNIGHT. THE PRESSURE GRADIENT WILL BE WEAK ACROSS
THE AREA EARLY BUT WILL TIGHTEN OVERNIGHT SO WINDS MAY DROP OFF
FOR A TIME EARLY BEFORE INCREASING SOMEWHAT OVERNIGHT. LOW TEMPS
WILL BE THE MAIN CHALLENGE AND MAY OCCUR DURING THE EVENING BUT
SOME WARMING MAY OCCUR LATE AS CLOUDS AND WINDS INCREASE AND WARM
ADVECTION IS UNDERWAY ALOFT. WILL GO AHEAD AND SHOW A STEADY OR
WARMING TREND OVERNIGHT. LIGHT PRECIP BECOMES A CONCERN BY
SATURDAY MORNING AS WAVES OF WARM ADVECTION BECOME MORE FOCUSED
AND MOISTURE DEEPENS. THIS IS WHERE TEMPS WILL BECOME CRITICAL
BECAUSE CHANCES FOR LIGHT PRECIP MAY BEGIN EARLY ENOUGH TO FALL AS
FREEZING RAIN. SIGNALS FOR PRECIP ARE NOT ALL THAT ORGANIZED UNTIL
SATURDAY AFTERNOON BUT WESTERN AREAS MAY HAVE DEEP ENOUGH MOISTURE
AND ENOUGH WARM ASCENT OCCURRING ALOFT TO SEE LIGHT RAIN...OR
FREEZING RAIN IF TEMPS START OUT BELOW FREEZING...BY LATE SATURDAY
MORNING. ANY FREEZING PRECIP WILL QUICKLY END AS TEMPS WARM WELL
ABOVE FREEZING BY EARLY AFTERNOON. PRECIP CHANCES WILL THEN EXPAND
EASTWARD...ESPECIALLY ACROSS THE NORTHERN CWA SATURDAY AFTERNOON
BUT CHANCES STILL LOOK RATHER LOW BUT STILL WORTH A MENTION GIVEN
STEADILY INCREASING DEEP LAYER MOISTURE /PRECIPITABLE WATER VALUES
REACH 0.75 INCHES OR SO BY LATE DAY/ AND WARM ADVECTION. SOUTH TO
SOUTHEAST WINDS WILL BECOME BREEZY WHICH WILL HELP HIGHS WARM INTO
LOW TO MID 40S NORTH AND MID TO UPPER 40S SOUTH. IT IS ALSO
IMPORTANT TO NOTE THAT DEW POINTS WILL BE ON THE RISE AS WELL
WHICH WILL COMBINE WITH THE STEADY WINDS AND MILD TEMPS TO PROVIDE
INCREASINGLY EFFICIENT SNOW MELT THROUGH THE AFTERNOON. MORE ON
THIS BELOW...
SATURDAY NIGHT AND SUNDAY...THE SOUTHWEST UPPER LOW WILL BE
LIFTING ACROSS THE SOUTHERN HIGH PLAINS AND PHASING WITH THE CENTRAL
CANADA UPPER TROUGH WHICH WILL BE SHARPENING AS IT PIVOTS
SOUTHEASTWARD. THE MAIN SURFACE LOW IS EXPECTED TO ORGANIZE IN
VICINITY OF THE SOUTHERN UPPER LOW ACROSS WESTERN KANSAS BY SATURDAY
EVENING WITH AN INVERTED TROUGH EXTENDING NORTHWARD INTO WESTERN
ONTARIO. GULF MOISTURE WILL CONTINUE TO STREAM NORTHWARD AHEAD OF
THE LOW AS 60KT LOW LEVEL JET SPREADS ACROSS
MISSOURI...ILLINOIS...AND LAKE MICHIGAN LATER SATURDAY EVENING.
PRECIPITABLE WATER VALUES WILL FURTHER SURGE REACHING THE 1 TO
PERHAPS 1.25 INCH RANGE WHICH WILL COMBINE WITH INCREASED ASCENT TO
PRODUCE WIDESPREAD RAIN ACROSS THE MID-MISSISSIPPI RIVER VALLEY
WHICH WILL THEN SPREAD EASTWARD DURING THE EVENING AND OVERNIGHT
HOURS. THE UPPER LOW WILL BE TO THE WEST OF THE AREA BY SUNDAY
MORNING WHICH WILL LIKELY BRING A DRY SLOT INTO THE AREA SOMETIME
SUNDAY MORNING. INSTABILITY DOES INCREASE AS WELL...POTENTIALLY WITH
ENOUGH ELEVATED INSTABILITY TO SUPPORT SOME THUNDER POTENTIAL ON THE
LEADING EDGE OF THE DRY SLOT. FURTHERMORE...SOME MINIMAL SURFACE
INSTABILITY COULD DEVELOP AS WELL WHICH WOULD POSE AN ADDITIONAL
THUNDER THREAT...ESPECIALLY ALONG THE APPROACHING COLD FRONT WHICH
WILL CROSS THE AREA LATER IN THE DAY. HOWEVER...THE DEEPER DRY AIR
OF THE DRY SLOT MAY PRECLUDE MUCH IF ANY DEVELOPMENT ALONG THE FRONT
IF SURFACE BASED INSTABILITY DOES IN FACT DEVELOP. STILL TOO EARLY
TO HAVE ANY HIGH DEGREE OF CONFIDENCE IN THUNDER POTENTIAL BUT FEEL
THIS BEARS WATCHING GIVEN THE HIGH DEGREE OF DEEP LAYER WIND SHEAR
AND FAIRLY STRONG LOW LEVEL WIND FIELD. HIGH TEMPS SUNDAY LOOK TO
RANGE FROM THE MID 40S NORTHWEST TO THE MID 50S SOUTHEAST.
PRECIP AMOUNTS/FLOODING POTENTIAL...FORECAST GUIDANCE IS IN PRETTY
GOOD AGREEMENT WITH THE TRACK OF LOW LEVEL FEATURES BUT DO DIFFER
IN THE PLACEMENT OF OTHER FEATURES SUCH AS THE PATH OF THE UPPER
JET CORE. QPF OUTPUT DOES DIFFER SOMEWHAT AS A RESULT...ESPECIALLY
IN PLACEMENT OF HEAVIEST VALUES. ARRIVAL TIMING MAY ALSO NEED
ADJUSTMENT WITH SOME GUIDANCE BEING SLOWER BUT RIGHT NOW THE
DIFFERENCES ARE ON THE ORDER OF A FEW HOURS. THE WESTERN AND
NORTHERN CWA CONTINUES TO LOOK TO HAVE THE BEST CHANCE AT
RECEIVING PEAK RAINFALL AMOUNTS...OR ROUGHLY FROM CHICAGO TO
PONTIAC AND POINTS WEST BUT THE ENTIRE CWA DOES LOOK TO SEE
RAINFALL. GIVEN THE PRECIPITABLE WATER VALUES AND DURATION OF
FORCING...AMOUNTS OF 0.75-1.00 INCHES ARE PLAUSIBLE IN THE NORTH
AND WEST WITH LESSER AMOUNTS SOUTHEAST. IF CONVECTION CAN DEVELOP
SUNDAY MORNING THEN AMOUNTS WOULD BE HIGHER IN SPOTS BUT IT IS
POSSIBLE THAT THE BEST CHANCE FOR CONVECTION COULD END UP BEING
ACROSS THE SOUTHERN/EASTERN CWA GIVEN THE LIKELY TRACK OF THE DRY
SLOT AND ARRIVAL OF INSTABILITY. SO CONFIDENCE IN SPECIFIC AMOUNTS
AND WHERE THEY OCCUR IS STILL LIMITED. HOWEVER...EVEN SOMEWHAT
LOWER AMOUNTS THAN THOSE ABOVE ARE STILL A CONCERN GIVEN THE
AMOUNT OF WATER IN THE CURRENT SNOW PACK. REFERENCE HYDROLOGY
SECTION BELOW AND ESFLOT PRODUCT FOR MORE DETAILS.
SUNDAY NIGHT AND MONDAY...TIMING DIFFERENCES BECOME MORE CRITICAL AS
THE SYSTEM DEPARTS SUNDAY NIGHT AND MONDAY. IN TERMS OF FRONTAL
TIMING...THERE IS GOOD AGREEMENT ON HAVING THE COLD FRONT SWEEP
ACROSS THE AREA SUNDAY AFTERNOON WHICH ALLOWS COLDER AIR TO
ARRIVE...BUT THE SPEED WITH WHICH IT ARRIVES IS NOT QUITE CLEAR. THE
ECMWF/GEM REMAIN SLOWER WITH THE PASSAGE OF THE UPPER TROUGH AXIS
DELAYING THE ARRIVAL OF COLDEST AIR...AS WELL AS THE ATTENDANT
DEFORMATION FORCING HOLDING IT OFF UNTIL CLOSER TO MONDAY MORNING.
THE NAM AND GFS ARE FASTER WITH THE UPPER TROUGH AND ARRIVAL OF COLD
AIR. THIS WILL PLAY HAVOC WITH PRECIP TIMING AND TYPE BEHIND THE
FRONT INTO MONDAY MORNING. WILL NEED TO MONITOR THIS PERIOD AS THERE
IS AT LEAST SOME SUPPORT FOR MEASURABLE PRECIP MONDAY.
MDB
LONG TERM...MONDAY NIGHT THROUGH FRIDAY...
THE EXTENDED PERIOD WILL FEATURE A FAIRLY PROGRESSIVE NORTHWEST TO
PERHAPS ZONAL FLOW WITH SEVERAL WEAK SYSTEMS TO AFFECT PART OF THE
REGION/GREAT LAKES. TIMING ANY OF THESE FEATURES IS SOMEWHAT
DIFFICULT AS THEIR STRENGTH/LOCATION CONTINUES TO FLUCTUATE FROM
RUN TO RUN AS WELL AS FROM MODEL TO MODEL. WHILE THERE WILL BE A
FEW CHANCES FOR PRECIP...WILL CONTINUE WITH MAINLY A DRY FORECAST
DUE TO LOW CONFIDENCE THOUGH HAVE INCLUDED A SLIGHT CHANCE OF
SHOWERS ON FRIDAY AS THERE HAS BEEN SOME CONTINUITY DURING THIS TIME
PERIOD. SHOULD PRECIP CHANCES/TRENDS INCREASE...PRECIP TYPE WILL
BECOME A CONCERN DEPENDING ON TIME OF DAY.
TEMPERATURES ARE EQUALLY CHALLENGING...DEPENDING ON THE TIMING OF
THESE FEATURES AND THE EXTENT OF COLD AIR THEY BRING WITH THEM.
ECMWF HAD BEEN FAIRLY CONSISTENT WITH A PUSH OF COLDER AIR THURSDAY
INTO FRIDAY WHICH IS NOW GONE WHILE THE GFS IS NOW MUCH COLDER. HAVE
TRENDED MIDDLE OF THE ROAD WITH TEMPS AND GIVEN MID MARCH SUNSHINE...
LACK OF ANY SIGNIFICANT COLD AIR PUSH WOULD SUPPORT TEMPS NEAR
SEASONAL NORMALS.
CMS
&&
.HYDROLOGY...
234 PM CST
SOME AREAS OF THE FORECAST AREA MAY SEE 0.75-1.00 INCHES
OF RAINFALL FROM SATURDAY THROUGH SUNDAY...WITH THE BULK EXPECTED
SATURDAY EVENING/NIGHT. AT THIS POINT...THESE RAINFALL AMOUNTS ARE
EXPECTED GENERALLY WEST OF A LINE FROM CHICAGO TO PONTIAC WITH
LESSER AMOUNTS SOUTHEAST BUT THERE IS SOME OPPORTUNITY FOR THE
LOCATION TO NEED ADJUSTMENT. IN ADDITION...SOME CONVECTIVE
RAINFALL IS POSSIBLE WHICH COULD RESULT IN LOCALLY HIGHER AMOUNTS.
OBSERVED SNOW CORE WATER EQUIVALENTS RANGE FROM AROUND AN INCH TO
AROUND 2.5 INCHES WHERE THE DEEPEST SNOW EXISTS...MAINLY NORTH OF
INTERSTATE 80. FROST DEPTH REMAINS IN THE 6 TO 10 INCH RANGE. THE
EXPECTATION IS THAT THE SNOW WILL MELT AND RUNOFF WILL BE REALIZED
BEFORE THE FROST MELTS SIGNIFICANTLY DUE TO THE INSULATING
EFFECTS OF THE SNOW PACK. SNOW MELT WILL COMMENCE BEFORE THE BULK
OF THE RAINFALL WHICH COULD ALLOW SOME OF THE RUNOFF INTO AREA
RIVERS AND STREAMS TO MAKE PROGRESS DOWNSTREAM BUT THIS WOULD
LIKELY BE MINIMAL. MOST MELT WILL LIKELY OCCUR WITH THE RAINFALL
SO RIVER RISES WILL OCCUR AND SOME RIVERS COULD EXCEED FLOOD STAGE
LATER SUNDAY/MONDAY. AREAL OVERLAND FLOODING IS A
POSSIBILITY...MAINLY IN LOW LYING AND POORLY DRAINED AREAS.
REFERENCE ESFLOT FOR ADDITIONAL INFORMATION.
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 03Z...
* GUSTY S TO SSE WINDS ON SAT AND SAT EVE.
* NEARBY LIGHT RAIN POSSIBLY REACHING THE AIRFIELDS SAT AFTERNOON.
* A CHANCE FOR FOG DEVELOPING SAT EVE.
//DISCUSSION...UPDATED 00Z...
HIGH PRESSURE ACROSS THE CENTRAL GREAT LAKES WILL CONTINUE TO
TRANSLATE EAST TONIGHT AS LOW PRESSURE DEVELOPS IN THE CENTRAL
PLAINS. AS THIS LOW FURTHER DEVELOPS ON SATURDAY WINDS WILL VEER
TO MORE OF A SSE DIRECTION AND INCREASE IN SPEED WITH GUSTINESS
FAVORED THROUGH THE DAY AND EVEN POTENTIALLY INTO THE NIGHT. MOIST
AIR RETURNING AHEAD OF THE LOW WILL GRADUALLY SATURATE THE
ATMOSPHERE. BELIEVE THAT BY DAYBREAK SATURDAY THERE WILL BE
SCATTERED LIGHT AREAS OF PRECIPITATION AS FAR EAST AS NORTH
CENTRAL IL AND BY AFTERNOON POSSIBLY TO CHICAGOLAND. TEMPERATURES
IN THE MORNING WILL LIKELY BE JUST BELOW FREEZING AT RFD WHERE
SOME MORNING RAIN MAY OCCUR SO MAINTAIN THE CHANCE FOR FREEZING
RAIN IN THAT PERIOD. OTHERWISE A MODERATION IN TEMPERATURES
THROUGH THE MORNING WILL END ANY THREAT OF THAT. RAIN WILL BE SLOW
TO SPREAD EAST THROUGH SAT EVE BUT THEN IS LIKELY TO RAPIDLY
EXPAND OVER BY OVERNIGHT WITH MVFR AND POSSIBLE IFR CONDITIONS.
PRIOR TO RAIN THERE IS A CHANCE FOR FOG DEVELOPMENT DUE TO SNOW
PACK SUBLIMATION AND INCREASING LOW-LEVEL MOISTURE. AT THIS TIME
HAVE NOT ADDED INTO THE TAFS BUT FULLY EXPECT VISBY REDUCTIONS
OVERNIGHT SAT NIGHT.
//ORD AND MDW CONFIDENCE...UPDATED 03Z...
* MEDIUM CONFIDENCE IN WIND TRENDS. DIRECTION COULD BE BETWEEN 130
AND 170 THROUGH SAT A.M.
* HIGH CONFIDENCE THAT IF RAIN WERE TO REACH THE AIRFIELDS PRIOR
TO END OF CURRENT TAFS IT WOULD BE LIGHT AND BE FROM VFR CIGS.
* LOW CONFIDENCE IN ANY FOG DEVELOPMENT PRIOR TO 06Z SUN BUT
CONFIDENCE INCREASES IN VISIBILITY REDUCTIONS JUST AFTER
/OVERNIGHT SAT NIGHT/.
//OUTLOOK FOR ORD/MDW FOR 12Z SUNDAY-12Z FRIDAY...UPDATED 00Z...
SUNDAY...RAIN AND FOG WITH LIKELY IFR. A CHANCE FOR A MIX WITH
SNOW DURING THE NIGHT.
MONDAY...SLIGHT CHANCE OF RAIN AND SNOW WITH MVFR.
TUESDAY-THURSDAY...VFR.
MTF
&&
.MARINE...
125 PM CST
THE HIGH PRESSURE THAT BROUGHT LIGHT AND VARIABLE WINDS TO LAKE
MICHIGAN HAS MOVED EAST OF THE LAKE AND WINDS HAVE BECOME
SOUTHERLY. AS DEEPENING LOW PRESSURE MOVES OUT OF THE ROCKIES AND
INTO THE SOUTHERN PLAINS...WHILE THE HIGH MOVES SLOWLY TO THE
EAST...THE GENERALLY SOUTHERLY WINDS WILL STRENGTHEN THROUGH THE
WEEKEND. BY SATURDAY EVENING...THE HIGH WILL MOVE TO THE EASTERN
SEABOARD WHILE THE LOW PRESSURE MOVER THE SOUTH HIGH PLAINS DEEPENS
AND A TROUGH OF LOW PRESSURE ELONGATES TO ANOTHER...WEAKER LOW JUST
NORTH OF MINNESOTA. SOUTHERLY WINDS WILL INCREASE TO AROUND 30 KT
AS THE TROUGH OF LOW PRESSURE AND AN ASSOCIATED COLD FRONT APPROACH
THE LAKE. THE COLD FRONT IS EXPECTED TO SWEEP ACROSS THE LAKE
SUNDAY...WITH WINDS QUICKLY VEERING TO NORTHERLY. WITH HIGH
PRESSURE QUICKLY BUILDING IN ACROSS THE LAKE BEHIND THE COLD
FRONT...THE NORTHERLY WINDS WILL ONLY BRIEFLY INCREASE TO AROUND 25
KT SUNDAY NIGHT BEFORE DROPPING OFF TO 5 TO 10 KT BY MONDAY NIGHT.
KREIN
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS LINCOLN IL
858 PM CST FRI MAR 8 2013
.DISCUSSION...
ISSUED 855 PM CST FRI MAR 8 2013
UPDATED THE FORECAST TO INCREASE CLOUD COVER TONIGHT AND ELEVATE
LOW TEMPERATURES UP A DEGREE OR TWO. LOWS RANGE FROM NEAR 30F OVER
EAST CENTRAL IL TO THE UPPER 30S FROM SPRINGFIELD SW. CONTINUE A
CHANCE OF LIGHT RAIN SHOWERS OVERNIGHT OVER THE IL RIVER VALLEY...
WITH BEST CHANCES NW OF THE IL RIVER LATE TONIGHT.
1031 MB HIGH PRESSURE OVER SE LOWER MI INTO OHIO AND EASTERN KY
THAT PROVIDE A NICE DAY TO CENTRAL/SE IL WITH AMPLE SUNSHINE AND
MILDER 40S WILL DRIFT INTO THE EASTERN GREAT LAKES SAT MORNING.
1001 MB LOW PRESSURE OVER SE CO WILL DEEPEN TO 997 MB NEAR THE SE
CO/SW KS BORDER BY MIDDAY SAT WITH A FRONTAL BOUNDARY EXTENDING NE
INTO FAR NW IA AND INTO MN. A WARM FRONT OVER SW MO INTO SOUTH
CENTRAL NE WILL LIFT NE TOWARD SW IL SAT MORNING. STRONG WAA
ADVECTION AND ISENTROPIC LIFT TO DEVELOP AND SPREAD LIGHT RAIN
SHOWERS FROM CENTRAL AND WESTERN MO/IA INTO THE IL RIVER VALLEY
OVERNIGHT INTO SAT MORNING MAINLY AFTER 09Z/3 AM. HRRR APPEARS TO
WET WITH SHOWERS OVER MOST OF CWA OVERNIGHT. SINCE SOUNDINGS ARE
QUITE DRY ESPECIALLY FROM I-55 EAST...THIS SHOULD KEEP AREAS FROM
I-55 EAST DRY TONIGHT. TEMPS CURRENTLY IN THE MID TO UPPER 30S
FROM MACOMB TO LINCOLN TO MATTOON NE AND 40-45F SW WILL SLIP ONLY
A FEW MORE DEGREES DUE TO INCREASING/THICKENING MID/HIGH CLOUDS AND
ESE WINDS OF 5-15 MPH.
07
&&
.AVIATION...
ISSUED 559 PM CST FRI MAR 8 2013
VFR CONDITIONS SHOULD CONTINUE ACROSS THE CENTRAL IL TERMINAL
AIRPORTS NEXT 24 HOURS THROUGH SUNSET SAT. BROKEN TO OVERCAST
MID/HIGH CLOUDS TO SPREAD ACROSS CENTRAL IL EARLY THIS EVENING AND
CONTINUE THROUGH SAT WITH CEILINGS LOWERING TO 8-12K FT OVERNIGHT
INTO SAT. BRUNT OF SHOWERS WILL STAY WEST OF CENTRAL IL TONIGHT
WITH A CHANCE OF SHOWERS BRUSHING PIA SAT MORNING WHERE VCSH
MAINTAINED. SE WINDS AROUND 10 KTS TONIGHT TO INCREASE TO AROUND
15 KTS WITH GUSTS 18-25 KTS AFTER 15Z SAT.
1031 MB HIGH PRESSURE OVER EASTERN LOWER MI/INDIANA AND WESTERN OHIO
TO DRIFT EAST INTO THE ATLANTIC STATES SAT AFTERNOON. MEANWHILE
1000 MB LOW PRESSURE DEEPENING OVER SE CO TO DEEPEN TO 997 MB INTO
SW KS BY SUNSET SAT. BRUNT OF ITS SHOWERS SHOULD STAY WEST OF
CENTRAL IL THROUGH SAT THOUGH WAA/ISENTROPIC LIFT INTO THE IL
RIVER VALLEY SAT MORNING COULD BRING A CHANCE OF SHOWERS TO PIA.
LOOKS LIKE A LULL IN SHOWER ACTIVITY OVER CENTRAL IL SAT AFTERNOON.
07
&&
.PREV DISCUSSION...
ISSUED 300 PM CST FRI MAR 8 2013
OUR SURFACE PATTERN IS CURRENTLY DOMINATED BY HIGH PRESSURE
EXTENDING FROM THE WESTERN GREAT LAKES ON SOUTH TO
MISSISSIPPI...WHILE LOW PRESSURE IN THE SOUTHWEST STATES BEGINS TO
MOVE ONSHORE AND DEVELOP UNDER A STRENGTHENING JET STREAM. THAT
SYSTEM WILL BECOME OUR MAIN WEATHER ISSUE FOR THE NEXT 3 DAYS OR
SO. OUTSIDE OF A BRIEF COOL DOWN ON MONDAY INTO
TUESDAY...TEMPERATURES OVER THE NEXT WEEK WILL BE AT OR ABOVE
NORMAL.
SHORT TERM...TONIGHT THROUGH SUNDAY NIGHT.
MID AND HIGH CLOUDS WILL ADVANCE INTO ILLINOIS TONIGHT AS MID
LEVEL WARM ADVECTION AND MOISTURE FLOWS BEGIN TO SATURATE THE
LOWER TROPOSPHERE. FORECAST SOUNDINGS ARE INDICATING MOST AREAS
WILL REMAIN DRY OVERNIGHT...ALTHOUGH WE CANT RULE OUT SOME LIGHT
RAIN SHOWERS FOR OUR FAR WESTERN COUNTIES FROM SCHUYLER TO KNOX
LATE TONIGHT. THE GFS IS THE ONLY MODEL TO BRING MUCH IN THE WAY
OF MEASURABLE RAIN BEFORE 12Z TO OUR WESTERN COUNTIES...SO WE
OPTED TO TREND VERY LOW ON THE POPS TONIGHT.
ON SATURDAY...THE PRIMARY FORCING FOR PRECIP WILL REMAIN FOCUSED
NORTHWEST OF I-55...WHILE AREAS SOUTHEAST OF I-55 REMAIN MAINLY
DRY. WE KEPT LIKELY POPS TOWARD FULTON AND KNOX COUNTIES...WITH
CHANCE POPS DOWN TO I-55. SOUTHEAST WINDS WILL BEGIN TO RESPOND TO
THE PRESSURE FALLS BY SATURDAY AFTERNOON...WITH WINDS IN THE 20-30
MPH RANGE AT TIMES. THE GUSTY WINDS WILL CONTINUE TO AID THE
MOISTURE TRANSPORT IN THE BOUNDARY LAYER SATURDAY NIGHT. WE
KEPT CATEGORICAL POPS SAT EVENING AND EXPANDED THEM NEARLY
EVERYWHERE AFTER MIDNIGHT.
THE BULK OF OUR RAINFALL AMOUNTS LOOK TO BE FOCUSED FROM MIDNIGHT
SATURDAY NIGHT THROUGH NOON ON SUNDAY...WITH ELEVATED THUNDERSTORMS
EVEN POSSIBLE AT TIMES LATE SAT NIGHT AND SUNDAY MORNING AS THE
COLD FRONT MOVES ACROSS THE AREA. WE KEPT THE MENTION OF THUNDER
MAINLY CONFINED WEST OF SPI SAT NIGHT AND SOUTH OF LINCOLN ON
SUNDAY MORNING. STRONG SOUTH WINDS WILL ACCOMPANY THE RAIN SHOWERS
AND STORMS AS THEY PUSH ACROSS THE AREA. WIND GUSTS OVER 30MPH
WILL BE POSSIBLE.
BY SUNDAY AFTERNOON THE BEST INSTABILITY WILL HAVE SHIFTED EAST
INTO INDIANA AS COLDER AIR BEGINS TO INVADE CENTRAL IL ON
NORTHWEST WINDS. DOWNWARD ISENTROPIC MOTIONS AND A DRY PUSH ALOFT
WILL HELP TO DIMINISH PRECIP SUNDAY NIGHT FROM NW TO SE. WE KEPT
CHANCE POPS IN THE SOUTHEAST HALF...WITH THE POTENTIAL FOR SOME
LIGHT SNOW NW OF I-70 AFTER MIDNIGHT. LITTLE IN THE WAY OF SNOW
ACCUMULATION IS EXPECTED...AS THE WET AND WARM GROUND MELTS MOST
OF ANY SNOWFALL.
LONG TERM...MONDAY THROUGH FRIDAY.
LINGERING LIGHT SNOW OR RAIN ON MONDAY MORNING SHOULD TAPER TO
SPRINKLES BY AFTERNOON. WE KEPT SLIGHT CHANCE POPS IN THE
SOUTHEAST...BUT MOST PRECIP SHOULD BE TRACE AMOUNTS BY THAT TIME.
THE COLDEST TEMPS OF THE NEXT WEEK SHOULD BE ON MONDAY AND MONDAY
NIGHT...WITH HIGHS ONLY AROUND 40 AND LOWS IN THE MID 20S. TEMPS
WILL BEGIN A WARMING TREND ON TUESDAY WHICH WILL CONTINUE THROUGH
THURSDAY WHEN HIGHS RETURN TO THE 50S. A COOL DOWN IS PROJECTED
FOR THURSDAY NIGHT INTO FRIDAY AS THE NEXT COLD FRONT MOVES
ACROSS THE AREA EITHER EARLY THURSDAY MORNING /GFS/ OR LATE
THURSDAY /ECMWF/. STILL THE COLDER AIR WILL NOT PLUNGE VERY FAR
SOUTH INTO OUR COUNTIES...SO THE COOL DOWN WILL BE TEMPORARY.
PRECIP CHANCES HAVE BEEN KEPT IN THE SLIGHT CHANCE CATEGORY...AND
ONLY ON FRIDAY FOR NOW.
SHIMON
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
138 PM CST THU MAR 7 2013
.DISCUSSION...
1006 AM CST
OTHER THAN A FEW TWEAKS TO HOURLY GRIDS...LITTLE/NO CHANGE TO GOING
FORECAST THIS MORNING. THIN BUT PERSISTENT LAYER OF STRATUS/STRATOCU
REMAINS ACROSS THE REGION...TRAPPED BENEATH STRONG INVERSION SEEN IN
THE 900-925 MB LAYER IN BOTH DVN AND ILX 12Z SOUNDINGS. WHILE SOME
CLEARING HAS OCCURRED OVER NORTHERN PARTS OF THE CHICAGO METRO AREA
AND LAKE MICHIGAN...CLOUDS ARE ACTUALLY SPREADING BACK NORTH ACROSS
EASTERN IA WEST OF THE LOW LEVEL HIGH PRESSURE RIDGE AXIS. DESPITE
BEING ABLE TO SEE TERRAIN FEATURES THROUGH THE THIN CLOUD LAYER ON
GOES VIS SATELLITE... SUSPECT THAT CLOUDS WILL BE HARD TO ERODE
TODAY. OTHER THAN A FEW PEEKS AT SOME BLUE SKY...MAINLY CLOUDY
CONDITIONS ARE EXPECTED. DEEP SNOW PACK AND THIN CLOUDY LAYER SHOULD
KEEP TEMPS IN CHECK WITHIN THE MID 30S OR SO.
RATZER
//PREV DISCUSSION...
330 AM CST
FORECAST CHALLENGES THIS MORNING INCLUDE CLOUDINESS THROUGH
TONIGHT...THEN THE BIG SLOPPY RAINY WET MELT DOWN EXPECTED THIS
WEEKEND.
STUBBORN STRATUS HAS NOT BUDGED AT ALL OVERNIGHT AND IS CURRENTLY
BLANKETING THE ENTIRE CWA. MODEL GUIDANCE IS NOT DOING A GREAT
JOB HANDLING CURRENT CONDITIONS WITH REGARDS TO THIS STRATUS DECK
WHICH LENDS ITSELF TO A LOWER CONFIDENCE FORECAST TODAY INTO
TONIGHT. RAP SEEMS TO HAVE THE BEST HANDLE ON LOW LEVEL RH AND IT
SUPPORTS WHAT I WAS THINKING WOULD HAPPEN CONCEPTUALLY WHICH IS
EROSION FROM THE EDGES COMMENCING AGAIN AFTER SUNRISE...ESPECIALLY
FROM THE SOUTHWEST WHERE SNOW PACK IS LESS OVER CENTRAL ILLINOIS.
RIDGE AXIS PASSING BY TODAY WILL THEN TURN LOW LEVEL EASTERLY
AND WHERE EVER THE EDGE OF THE STRATUS ENDS UP LATE THIS AFTERNOON
COULD SEE IT RE-DEVELOPING/RE-ADVECTING BACK WEST ACROSS THE CWA
TONIGHT. HUNCH IS THAT EASTERN CWA COULD STAY PRETTY SOCKED IN
TODAY WITH SOME CLEARING WEST THIS AFTERNOON BUT WITH POTENTIAL
FOR REDEVELOPMENT OF STRATUS TONIGHT. TRYING TO REFLECT THESE
TRENDS IN THE GRIDS IS GOING TO BE A CHALLENGE TO SAY THE LEAST...
TEMPS WILL BE HELD DOWN BY CLOUDS AND SNOW COVER TODAY...AND THEN
HELD UP TONIGHT WHERE STATUS ENDS UP PARKING. WESTERN CWA STANDS A
CHANCE OF SEEING CLEAR SKIES THIS EVENING AND A RAPID TEMP DROP.
GIVEN THE LIGHT WINDS THERE IS A POTENTIAL FOR SOME FREEZING
GROUND FOG DEVELOPING PRIOR TO THE ARRIVAL OF ANY STRATUS. ONCE
AGAIN TONIGHT LOW TEMPERATURE FORECAST IS VERY LOW CONFIDENCE WITH
ABOUT A 15-20F RANGE OF POSSIBLE LOWS...ESPECIALLY WESTERN CWA.
SAME DEAL FRIDAY...IF STRATUS DECK NEVER CLEARS OUT THEN CLOUDY
START WITH POSSIBLE SCATTERING OUT IN THE AFTERNOON WOULD BE
EXPECTED WITH COLDER TEMPS. CONVERSELY...SHOULD THE STRATUS BE
GONE SUNNY SKIES WITH HIGHER SUN ANGLE MARCH SUN COULD RESULT IN
FRIDAY TURNING INTO DAY 1 OF THE GREAT MELT DOWN WITH HIGHS
GETTING WELL INTO THE 30S AND MAYBE LOW 40S IN SOUTHERN CWA AND IN
MORE URBANIZED AREAS.
WEEKEND FORECAST STILL GENERALLY LOOKS ON TRACK...THOUGH MODELS HAVE
TRENDED TOWARD A SLIGHTLY WEAKER/LESS PHASED SOLUTION WOULD MEAN A
SOMEWHAT LESSER THREAT OF HEAVY RAINFALL. WE ARE STILL PRETTY FAR
OUT IN TIME AND WOULD ANTICIPATE MORE CHANGES IN FORECAST GUIDANCE
THE NEXT COUPLE DAYS...MOST LIKELY TO SLOW THE SYSTEM DOWN IF
ANYTHING...SO NOT GOING TO MAKE ANY BIG CHANGES TO GOING FORECAST
FOR THE WEEKEND. EARLY NEXT WEEK THE RUNS DE JOUR OF THE MEDIUM
RANGE GUIDANCE LOOKS LESS FOREBODING REGARDING A SNOW SYSTEM WITH A
LESS PHASED MORE POSITIVELY TILTED/PROGRESSIVE TROUGH MOVING THROUGH
BUT STILL PLENTY OF TIME FOR THAT TO CHANGE SO PROBABLY A LITTLE
PREMATURE TO PUT AWAY THE SHOVELS FOR THE YEAR YET.
IZZI
&&
.HYDROLOGY...
330 AM CST
DEEP WATER LOGGED SNOW PACK BLANKETS THE CWA WITH SNOW WATER
EQUIV`S NEAR TO OVER AN INCH OVER NORTHERN HALF OF THE CWA. RISING
TEMPS AND DEWPOINTS THIS WEEKEND SHOULD RESULT IN AN INCREASING
QUICK MELTING OF THE SNOW PACK...WITH ANY RAIN FALLING ON TOP OF
IT SERVING TO FURTHER INCREASE THE CHANCE OF SOME FLOODING
PROBLEMS DEVELOPING. CONFIDENCE IN RAINFALL TOTALS THIS WEEKEND
NOT OVERLY HIGH...BUT EARLY BALL PARK NUMBERS IN THE HALF INCH TO
ONE INCH RANGE LOOK QUITE PLAUSIBLE AND SUFFICIENT FOR SIGNIFICANT
RISES ON AREA RIVERS AND POTENTIAL FOR FLOODING. WILL CONTINUE TO
HIGHLIGHT THREAT IN THE HWO AND DAY SHIFT MAY NEED TO CONSIDER AN
ESF.
IZZI
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 20Z...
* SLIGHT CHANCE FOR VIS RESTRICTIONS IN BR EARLY FRIDAY MORNING.
KREIN
//DISCUSSION...UPDATED 18Z...
MAIN ISSUE FOR THE REMAINDER OF THE AFTERNOON AND INTO THIS
EVENING WILL BE CEILINGS. THE LOWER END VFR STRATOCU DECK REMAINS
IN PLACE OVER MUCH OF THE AREA...LOWERING TO HIGH END MVFR CIGS
WEST OF THE CHICAGO AREA INCLUDING RFD. A CLEARING SLOT HAD PUSHED
SOUTH OVER FAR NERN IL THIS MORNING...ALLOWING ORD TO BRIEFLY
IMPROVE TO SCT035...BUT THE STRATOCU HAS FILLED BACK TO BKN-
OVC035. WHILE THE LATEST VISIBLE SATELLITE IMAGERY INDICATES THAT
THE CLOUD IS VERY THIN...WITH SFC FEATURES SHOWING THROUGH THE
CLOUD COVER...THE 11-3.9 MICRON IMAGERY MUCH BETTER SHOWS THE
EXTENT OF THE CLOUD COVER...WITH LATEST TRENDS INDICATING NO
TREND OF CLOUD COVER TO IMPROVE. ALSO...MODEL SOUNDING CONTINUE TO
INDICATE A WEAK INVERSION IN PLACE THROUGH THE AFTERNOON AND THIS
EVENING...SO DO NOT EXPECT ANY DEEP LAYER MIXING TO HELP BREAK UP
THE CLOUD COVER. WITH THE SFC RIDGE MOVING ACROSS THE
AREA...EXPECT THAT WINDS WILL BE LGT/VRBL TO CALM THROUGH MUCH OF
THE PERIOD...BEFORE BECOMING MORE SELY AND STRENGTHENING TOMORROW
MORNING AS THE SFC RIDGE PUSHES TO THE EAST. HAVE SOME CONCERN FOR
REDUCED VISBY IN BR/FG OVERNIGHT TONIGHT WITH LIGHT WINDS AND
DECREASING CLOUD COVER. HOWEVER...CONFIDENCE IS NOT HIGH IN THE
CLOUD COVER TRENDS. ALSO...SFC DEWPOINTS ARE EXPECTED TO REMAIN
FAIRLY LOW...SO DO NOT HAVE HIGH ENOUGH CONFIDENCE IN THE
POTENTIAL FOR REDUCED VISBY TONIGHT TO INCLUDE IN THE TAFS JUST
YET.
LOOKING AHEAD TO THIS WEEKEND...LOOKING AT THE POTENTIAL FOR
WIDESPREAD FOG DEVELOPMENT AS STRONG MOIST ADVECTION DRIVES
DEWPOINTS INTO THE 30S AND EVENTUALLY 40S OVER DEEP SNOW PACK. THIS
TYPE OF SETUP HAS THE POTENTIAL FOR PRODUCING WIDESPREAD AND
POTENTIALLY DENSE FOG.
KREIN
//ORD AND MDW CONFIDENCE...UPDATED 20Z...
* LOW CONFIDENCE ON TIMING SCATTERING OF THE STRATOCU DECK...AND
THE POTENTIAL FOR BR/FG LATE TONIGHT INTO EARLY TOMORROW
MORNING.
* MEDIUM TO HIGH CONFIDENCE IN ALL OTHER FORECAST ELEMENTS.
KREIN
//OUTLOOK FOR ORD/MDW FOR 00Z SATURDAY-12Z THURSDAY...UPDATED 12Z...
FRIDAY NIGHT THROUGH SATURDAY...VFR.
SATURDAY NIGHT THROUGH SUNDAY...RAIN/FOG.
MONDAY...CHC RAIN/SNOW.
TUESDAY THROUGH WEDNESDAY...VFR.
BMD
&&
.MARINE...
1245 PM CST
SURFACE HIGH PRESSURE RIDGING STRETCHING FROM ONTARIO SOUTH ACROSS
WISCONSIN AND ILLINOIS WILL CONTINUE TO DRIFT EAST ACROSS LAKE
MICHIGAN THROUGH FRIDAY. DECREASING LIGHT NORTH WINDS WILL BECOME
SOUTHEAST ON FRIDAY...INCREASING MODESTLY FRIDAY NIGHT AND BECOMING
MORE SOUTHERLY AS LOW PRESSURE DEVELOPS AND DEEPENS ACROSS THE HIGH
PLAINS TO THE WEST.
LOW PRESSURE WILL LIFT NORTHEAST ACROSS THE CENTRAL PLAINS ON
SATURDAY...WITH THE SURFACE PRESSURE GRADIENT ACROSS THE WESTERN
LAKES TIGHTENING IN RESPONSE TO THE DEVELOPMENT AND APPROACH OF THE
LOW. WITH RELATIVELY MILD SOUTHERLY FLOW ACROSS THE AREA...FORECAST
SOUNDINGS INDICATE THAT LOW LEVEL LAPSE RATES WILL NOT BE
PARTICULARLY STEEP...AND SUPPORT WINDS INCREASING TO 20-25 KT FOR
THE MOST PART SATURDAY AFTERNOON AND NIGHT WITH PERHAPS SOME GUSTS
AROUND 30 KT. STRONGER WINDS...GALES IN THE 35-45 KT RANGE...WILL
EXIST JUST 1000 FT AGL...THOUGH THE WEAK LAPSE RATES SUGGEST IT MAY
BE TOUGH TO MIX THESE WINDS TO THE SURFACE WITH THE AIR BECOMING
WARMER THAN THE LAKE SURFACE.
THE GENERAL TREND IN FORECAST MODEL GUIDANCE OVER THE PAST FEW RUNS
HAS BEEN TO WEAKEN THE LOW AS IT MOVES INTO THE WESTERN LAKES REGION
EARLY SUNDAY...WHICH SHOULD ALLOW SOUTH WINDS TO WEAKEN LATE
SATURDAY NIGHT OR SUNDAY MORNING AS THE GRADIENT WEAKENS AND BECOMES
BAGGY WITH THE SURFACE TROUGH/LOW APPROACH FROM THE WEST/SOUTHWEST.
SOUTH WINDS ARE THUS EXPECTED TO DIMINISH AND THEN VEER TO THE NORTH
DURING THE DAY SUNDAY AS THE TROUGH/COLD FRONT PASS. NORTH WINDS
THEN LOOK TO INCREASE BEHIND THE FRONT...AS THE GRADIENT TIGHTENS
AGAIN AHEAD OF HIGH PRESSURE SPREADING ACROSS ONTARIO AND THE UPPER
MIDWEST...AND WITH COLDER AIR BEHIND THE FRONT PRODUCING MUCH
STEEPER LOW LEVEL LAPSE RATES ALLOWING MIXING OF STRONGER WINDS TO
THE SURFACE. NORTH WINDS TO 30 KTS APPEAR TO BE A FAIRLY HIGH
PROBABILITY SUNDAY AFTERNOON AND NIGHT...WITH THE POTENTIAL FOR
NORTH GALES. WINDS THEN DECREASE MONDAY AS THE SURFACE RIDGE
APPROACHES.
RATZER
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
1246 PM CST THU MAR 7 2013
.DISCUSSION...
1006 AM CST
OTHER THAN A FEW TWEAKS TO HOURLY GRIDS...LITTLE/NO CHANGE TO GOING
FORECAST THIS MORNING. THIN BUT PERSISTENT LAYER OF STRATUS/STRATOCU
REMAINS ACROSS THE REGION...TRAPPED BENEATH STRONG INVERSION SEEN IN
THE 900-925 MB LAYER IN BOTH DVN AND ILX 12Z SOUNDINGS. WHILE SOME
CLEARING HAS OCCURRED OVER NORTHERN PARTS OF THE CHICAGO METRO AREA
AND LAKE MICHIGAN...CLOUDS ARE ACTUALLY SPREADING BACK NORTH ACROSS
EASTERN IA WEST OF THE LOW LEVEL HIGH PRESSURE RIDGE AXIS. DESPITE
BEING ABLE TO SEE TERRAIN FEATURES THROUGH THE THIN CLOUD LAYER ON
GOES VIS SATELLITE... SUSPECT THAT CLOUDS WILL BE HARD TO ERODE
TODAY. OTHER THAN A FEW PEEKS AT SOME BLUE SKY...MAINLY CLOUDY
CONDITIONS ARE EXPECTED. DEEP SNOW PACK AND THIN CLOUDY LAYER SHOULD
KEEP TEMPS IN CHECK WITHIN THE MID 30S OR SO.
RATZER
//PREV DISCUSSION...
330 AM CST
FORECAST CHALLENGES THIS MORNING INCLUDE CLOUDINESS THROUGH
TONIGHT...THEN THE BIG SLOPPY RAINY WET MELT DOWN EXPECTED THIS
WEEKEND.
STUBBORN STRATUS HAS NOT BUDGED AT ALL OVERNIGHT AND IS CURRENTLY
BLANKETING THE ENTIRE CWA. MODEL GUIDANCE IS NOT DOING A GREAT
JOB HANDLING CURRENT CONDITIONS WITH REGARDS TO THIS STRATUS DECK
WHICH LENDS ITSELF TO A LOWER CONFIDENCE FORECAST TODAY INTO
TONIGHT. RAP SEEMS TO HAVE THE BEST HANDLE ON LOW LEVEL RH AND IT
SUPPORTS WHAT I WAS THINKING WOULD HAPPEN CONCEPTUALLY WHICH IS
EROSION FROM THE EDGES COMMENCING AGAIN AFTER SUNRISE...ESPECIALLY
FROM THE SOUTHWEST WHERE SNOW PACK IS LESS OVER CENTRAL ILLINOIS.
RIDGE AXIS PASSING BY TODAY WILL THEN TURN LOW LEVEL EASTERLY
AND WHERE EVER THE EDGE OF THE STRATUS ENDS UP LATE THIS AFTERNOON
COULD SEE IT RE-DEVELOPING/RE-ADVECTING BACK WEST ACROSS THE CWA
TONIGHT. HUNCH IS THAT EASTERN CWA COULD STAY PRETTY SOCKED IN
TODAY WITH SOME CLEARING WEST THIS AFTERNOON BUT WITH POTENTIAL
FOR REDEVELOPMENT OF STRATUS TONIGHT. TRYING TO REFLECT THESE
TRENDS IN THE GRIDS IS GOING TO BE A CHALLENGE TO SAY THE LEAST...
TEMPS WILL BE HELD DOWN BY CLOUDS AND SNOW COVER TODAY...AND THEN
HELD UP TONIGHT WHERE STATUS ENDS UP PARKING. WESTERN CWA STANDS A
CHANCE OF SEEING CLEAR SKIES THIS EVENING AND A RAPID TEMP DROP.
GIVEN THE LIGHT WINDS THERE IS A POTENTIAL FOR SOME FREEZING
GROUND FOG DEVELOPING PRIOR TO THE ARRIVAL OF ANY STRATUS. ONCE
AGAIN TONIGHT LOW TEMPERATURE FORECAST IS VERY LOW CONFIDENCE WITH
ABOUT A 15-20F RANGE OF POSSIBLE LOWS...ESPECIALLY WESTERN CWA.
SAME DEAL FRIDAY...IF STRATUS DECK NEVER CLEARS OUT THEN CLOUDY
START WITH POSSIBLE SCATTERING OUT IN THE AFTERNOON WOULD BE
EXPECTED WITH COLDER TEMPS. CONVERSELY...SHOULD THE STRATUS BE
GONE SUNNY SKIES WITH HIGHER SUN ANGLE MARCH SUN COULD RESULT IN
FRIDAY TURNING INTO DAY 1 OF THE GREAT MELT DOWN WITH HIGHS
GETTING WELL INTO THE 30S AND MAYBE LOW 40S IN SOUTHERN CWA AND IN
MORE URBANIZED AREAS.
WEEKEND FORECAST STILL GENERALLY LOOKS ON TRACK...THOUGH MODELS HAVE
TRENDED TOWARD A SLIGHTLY WEAKER/LESS PHASED SOLUTION WOULD MEAN A
SOMEWHAT LESSER THREAT OF HEAVY RAINFALL. WE ARE STILL PRETTY FAR
OUT IN TIME AND WOULD ANTICIPATE MORE CHANGES IN FORECAST GUIDANCE
THE NEXT COUPLE DAYS...MOST LIKELY TO SLOW THE SYSTEM DOWN IF
ANYTHING...SO NOT GOING TO MAKE ANY BIG CHANGES TO GOING FORECAST
FOR THE WEEKEND. EARLY NEXT WEEK THE RUNS DE JOUR OF THE MEDIUM
RANGE GUIDANCE LOOKS LESS FOREBODING REGARDING A SNOW SYSTEM WITH A
LESS PHASED MORE POSITIVELY TILTED/PROGRESSIVE TROUGH MOVING THROUGH
BUT STILL PLENTY OF TIME FOR THAT TO CHANGE SO PROBABLY A LITTLE
PREMATURE TO PUT AWAY THE SHOVELS FOR THE YEAR YET.
IZZI
&&
.HYDROLOGY...
330 AM CST
DEEP WATER LOGGED SNOW PACK BLANKETS THE CWA WITH SNOW WATER
EQUIV`S NEAR TO OVER AN INCH OVER NORTHERN HALF OF THE CWA. RISING
TEMPS AND DEWPOINTS THIS WEEKEND SHOULD RESULT IN AN INCREASING
QUICK MELTING OF THE SNOW PACK...WITH ANY RAIN FALLING ON TOP OF
IT SERVING TO FURTHER INCREASE THE CHANCE OF SOME FLOODING
PROBLEMS DEVELOPING. CONFIDENCE IN RAINFALL TOTALS THIS WEEKEND
NOT OVERLY HIGH...BUT EARLY BALL PARK NUMBERS IN THE HALF INCH TO
ONE INCH RANGE LOOK QUITE PLAUSIBLE AND SUFFICIENT FOR SIGNIFICANT
RISES ON AREA RIVERS AND POTENTIAL FOR FLOODING. WILL CONTINUE TO
HIGHLIGHT THREAT IN THE HWO AND DAY SHIFT MAY NEED TO CONSIDER AN
ESF.
IZZI
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 18Z...
* SLIGHT CHANCE FOR VIS RESTRICTIONS IN BR EARLY FRIDAY MORNING.
KREIN
//DISCUSSION...UPDATED 18Z...
MAIN ISSUE FOR THE REMAINDER OF THE AFTERNOON AND INTO THIS
EVENING WILL BE CEILINGS. THE LOWER END VFR STRATOCU DECK REMAINS
IN PLACE OVER MUCH OF THE AREA...LOWERING TO HIGH END MVFR CIGS
WEST OF THE CHICAGO AREA INCLUDING RFD. A CLEARING SLOT HAD PUSHED
SOUTH OVER FAR NERN IL THIS MORNING...ALLOWING ORD TO BRIEFLY
IMPROVE TO SCT035...BUT THE STRATOCU HAS FILLED BACK TO BKN-
OVC035. WHILE THE LATEST VISIBLE SATELLITE IMAGERY INDICATES THAT
THE CLOUD IS VERY THIN...WITH SFC FEATURES SHOWING THROUGH THE
CLOUD COVER...THE 11-3.9 MICRON IMAGERY MUCH BETTER SHOWS THE
EXTENT OF THE CLOUD COVER...WITH LATEST TRENDS INDICATING NO
TREND OF CLOUD COVER TO IMPROVE. ALSO...MODEL SOUNDING CONTINUE TO
INDICATE A WEAK INVERSION IN PLACE THROUGH THE AFTERNOON AND THIS
EVENING...SO DO NOT EXPECT ANY DEEP LAYER MIXING TO HELP BREAK UP
THE CLOUD COVER. WITH THE SFC RIDGE MOVING ACROSS THE
AREA...EXPECT THAT WINDS WILL BE LGT/VRBL TO CALM THROUGH MUCH OF
THE PERIOD...BEFORE BECOMING MORE SELY AND STRENGTHENING TOMORROW
MORNING AS THE SFC RIDGE PUSHES TO THE EAST. HAVE SOME CONCERN FOR
REDUCED VISBY IN BR/FG OVERNIGHT TONIGHT WITH LIGHT WINDS AND
DECREASING CLOUD COVER. HOWEVER...CONFIDENCE IS NOT HIGH IN THE
CLOUD COVER TRENDS. ALSO...SFC DEWPOINTS ARE EXPECTED TO REMAIN
FAIRLY LOW...SO DO NOT HAVE HIGH ENOUGH CONFIDENCE IN THE
POTENTIAL FOR REDUCED VISBY TONIGHT TO INCLUDE IN THE TAFS JUST
YET.
LOOKING AHEAD TO THIS WEEKEND...LOOKING AT THE POTENTIAL FOR
WIDESPREAD FOG DEVELOPMENT AS STRONG MOIST ADVECTION DRIVES
DEWPOINTS INTO THE 30S AND EVENTUALLY 40S OVER DEEP SNOW PACK. THIS
TYPE OF SETUP HAS THE POTENTIAL FOR PRODUCING WIDESPREAD AND
POTENTIALLY DENSE FOG.
KREIN
//ORD AND MDW CONFIDENCE...UPDATED 18Z...
* LOW CONFIDENCE ON TIMING SCATTERING OF THE STRATOCU DECK...AND
THE POTENTIAL FOR BR/FG LATE TONIGHT INTO EARLY TOMORROW
MORNING.
* MEDIUM TO HIGH CONFIDENCE IN ALL OTHER FORECAST ELEMENTS.
KREIN
//OUTLOOK FOR ORD/MDW FOR 00Z SATURDAY-12Z THURSDAY...UPDATED 12Z...
FRIDAY NIGHT THROUGH SATURDAY...VFR.
SATURDAY NIGHT THROUGH SUNDAY...RAIN/FOG.
MONDAY...CHC RAIN/SNOW.
TUESDAY THROUGH WEDNESDAY...VFR.
BMD
&&
.MARINE...
1245 PM CST
SURFACE HIGH PRESSURE RIDGING STRETCHING FROM ONTARIO SOUTH ACROSS
WISCONSIN AND ILLINOIS WILL CONTINUE TO DRIFT EAST ACROSS LAKE
MICHIGAN THROUGH FRIDAY. DECREASING LIGHT NORTH WINDS WILL BECOME
SOUTHEAST ON FRIDAY...INCREASING MODESTLY FRIDAY NIGHT AND BECOMING
MORE SOUTHERLY AS LOW PRESSURE DEVELOPS AND DEEPENS ACROSS THE HIGH
PLAINS TO THE WEST.
LOW PRESSURE WILL LIFT NORTHEAST ACROSS THE CENTRAL PLAINS ON
SATURDAY...WITH THE SURFACE PRESSURE GRADIENT ACROSS THE WESTERN
LAKES TIGHTENING IN RESPONSE TO THE DEVELOPMENT AND APPROACH OF THE
LOW. WITH RELATIVELY MILD SOUTHERLY FLOW ACROSS THE AREA...FORECAST
SOUNDINGS INDICATE THAT LOW LEVEL LAPSE RATES WILL NOT BE
PARTICULARLY STEEP...AND SUPPORT WINDS INCREASING TO 20-25 KT FOR
THE MOST PART SATURDAY AFTERNOON AND NIGHT WITH PERHAPS SOME GUSTS
AROUND 30 KT. STRONGER WINDS...GALES IN THE 35-45 KT RANGE...WILL
EXIST JUST 1000 FT AGL...THOUGH THE WEAK LAPSE RATES SUGGEST IT MAY
BE TOUGH TO MIX THESE WINDS TO THE SURFACE WITH THE AIR BECOMING
WARMER THAN THE LAKE SURFACE.
THE GENERAL TREND IN FORECAST MODEL GUIDANCE OVER THE PAST FEW RUNS
HAS BEEN TO WEAKEN THE LOW AS IT MOVES INTO THE WESTERN LAKES REGION
EARLY SUNDAY...WHICH SHOULD ALLOW SOUTH WINDS TO WEAKEN LATE
SATURDAY NIGHT OR SUNDAY MORNING AS THE GRADIENT WEAKENS AND BECOMES
BAGGY WITH THE SURFACE TROUGH/LOW APPROACH FROM THE WEST/SOUTHWEST.
SOUTH WINDS ARE THUS EXPECTED TO DIMINISH AND THEN VEER TO THE NORTH
DURING THE DAY SUNDAY AS THE TROUGH/COLD FRONT PASS. NORTH WINDS
THEN LOOK TO INCREASE BEHIND THE FRONT...AS THE GRADIENT TIGHTENS
AGAIN AHEAD OF HIGH PRESSURE SPREADING ACROSS ONTARIO AND THE UPPER
MIDWEST...AND WITH COLDER AIR BEHIND THE FRONT PRODUCING MUCH
STEEPER LOW LEVEL LAPSE RATES ALLOWING MIXING OF STRONGER WINDS TO
THE SURFACE. NORTH WINDS TO 30 KTS APPEAR TO BE A FAIRLY HIGH
PROBABILITY SUNDAY AFTERNOON AND NIGHT...WITH THE POTENTIAL FOR
NORTH GALES. WINDS THEN DECREASE MONDAY AS THE SURFACE RIDGE
APPROACHES.
RATZER
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS LINCOLN IL
1141 AM CST THU MAR 7 2013
.DISCUSSION...
ISSUED 951 AM CST THU MAR 7 2013
CLOUDS CONTINUE TO PLAGUE CENTRAL AND SOUTHEAST ILLINOIS THIS
MORNING...THANKS TO MOISTURE TRAPPED BENEATH A STRONG LOW-LEVEL
SUBSIDENCE INVERSION. LATEST VISIBLE SATELLITE IMAGERY SHOWS A
RATHER THIN OVERCAST ACROSS THE REGION...WITH MAJOR RIVERS DIMLY
VISIBLE THROUGH THE CLOUD COVER. GIVEN RELATIVE THINNESS OF CLOUDS
AND STRENGTH OF EARLY MARCH SUN...THINK A FEW HOLES WILL BE
PUNCHED IN THE OVERCAST AS THE DAY GOES ON. HOWEVER...WITH STRONG
INVERSION IN PLACE AND LITTLE OR NO WIND...EXPECT GENERALLY CLOUDY
CONDITIONS THROUGH THE DAY. WINDS WILL BECOME LIGHT AND EASTERLY
LATER TODAY/TONIGHT...AS SURFACE HIGH SHIFTS INTO THE OHIO RIVER
VALLEY. THIS MAY TEND TO ADVECT LOW-LEVEL MOISTURE BACK INTO THE
AREA TONIGHT. WHILE 12Z NAM FORECAST SOUNDINGS INDICATE CLEARING
BY EVENING...14Z RUC SOUNDINGS MAY HAVE A BETTER HANDLE ON
REALITY...INDICATING MOSTLY CLOUDY CONDITIONS PERSISTING THROUGH
THE NIGHT.
&&
.AVIATION...
ISSUED 1141 AM CST THU MAR 7 2013
CLOUDS CONTINUE TO BLANKET CENTRAL ILLINOIS LATE THIS
MORNING...HOWEVER EARLY MARCH SUN IS BEGINNING TO ERODE THE W/SW
EDGE OF THE OVERCAST. SINCE CLOUDS ARE RELATIVELY THIN...THINK
THIS PROCESS WILL CONTINUE FOR THE NEXT 3 TO 4 HOURS. AS A
RESULT...HAVE SCATTERED THE MVFR CEILINGS AT KSPI BY 19Z AND AT
KPIA BY 20Z. WILL KEEP AN EYE ON SATELLITE TRENDS FOR POTENTIAL
CLEARING FURTHER EASTWARD...BUT FOR NOW HAVE OPTED TO CONTINUE THE
CEILINGS AT THE REMAINING TERMINALS THROUGHOUT THE AFTERNOON. ONCE
THE SUN SETS AND LOW-LEVEL FLOW TAKES ON A LIGHT EASTERLY
COMPONENT...THINK MOISTURE WILL ADVECT BACK WESTWARD...RESULTING
IN CLOUDY CONDITIONS THROUGH THE NIGHT. AS SURFACE HIGH PRESSURE
SLIDES FURTHER EASTWARD AND WINDS BEGIN TO INCREASE FROM THE
SOUTHEAST...SKIES WILL FINALLY CLEAR OUT ACROSS THE BOARD BY
FRIDAY MORNING.
BARNES
&&
.PREV DISCUSSION...
ISSUED 307 AM CST THU MAR 7 2013
EARLY MORNING SURFACE MAP SHOWED HIGH PRESSURE RIDGING RUNNING THE
LENGTH OF THE MISSISSIPPI RIVER. RATHER TIGHT INVERSION JUST ABOVE
900 MB HAS PUT THE KIBOSH ON ANY REAL EROSION OF THE LARGE
STRATOCUMULUS DECK OVER MUCH OF THE MIDWEST...WITH ONLY AREAS
AROUND JACKSONVILLE SEEING ANY SUSTAINED CLEARING AND THAT HAS
BEGUN TO FILL IN AS WELL. THE CLOUDS HAVE KEPT TEMPERATURES IN THE
20S...WHICH IS GOOD SINCE CLEAR SKIES OVER THE SUBSTANTIAL SNOW
COVER IN THE NORTHERN CWA WOULD HAVE LIKELY RESULTED IN SINGLE
DIGITS AND TEENS IN THAT AREA. LOOKING UPSTAIRS...LATEST WATER
VAPOR IMAGERY SHOWING SEVERAL CIRCULATIONS IN A BROAD AREA OF 500
MB LOW PRESSURE OVER THE PACIFIC NORTHWEST. DEVELOPMENT OF THIS
PARTICULAR FEATURE WILL BE OF INTEREST TO OUR FORECAST FOR THE
WEEKEND.
SHORT TERM...TODAY THROUGH FRIDAY...
FAIRLY QUIET WEATHER EXPECTED IN THE SHORT TERM...AS THE HIGH
PUSHES EAST ACROSS THE GREAT LAKES. FORECAST SOUNDINGS SHOW THE
INVERSION SLOW TO ERODE THOUGH...SO WILL KEEP THE EASTERN CWA
FAIRLY CLOUDY TODAY AND TRY TO MARK SOME CLEARING ACROSS THE WEST
BY MIDDAY. MAIN CONCERN WILL BE WITH FOG POTENTIAL TONIGHT ACROSS
THE NORTH...WITH WINDS STILL FAIRLY LIGHT AND SOME POTENTIAL FOR
SNOW MELT TODAY. SHOULD SKIES STAY CLOUDY...THIS WOULD BE LESS OF
A CONCERN.
TEMPERATURE-WISE...WILL CONTINUE THE TREND OF KEEPING HIGHS A FEW
DEGREES COOLER ACROSS THE NORTH WHERE THE SNOW DEPTH RANGES FROM 5
TO 9 INCHES. HOWEVER...EVEN THESE AREAS MAY CRACK 40 BY FRIDAY...
WITH HIGHS 45-50 FURTHER SOUTH.
LONG TERM...SATURDAY THROUGH WEDNESDAY...
UPPER LOW IN THE PACIFIC NORTHWEST SHOULD BETTER ORGANIZE AS IT
DROPS SOUTHWARD ALONG THE CALIFORNIA COAST TONIGHT AND FRIDAY.
LATEST MODEL GUIDANCE CONTINUES TO EJECT THIS FEATURE NORTHEAST
THIS WEEKEND...AS A DEEPENING SHORTWAVE TRACKS EAST ACROSS THE
CANADIAN PRAIRIES. SOME PHASING OF THE TWO FEATURES IS INDICATED
LATER THIS WEEKEND OVER THE CENTRAL U.S. AND THIS WILL
SIGNIFICANTLY INCREASE PRECIP CHANCES AS THE WEEKEND PROGRESSES.
GOOD MOISTURE SURGE SHOULD TAKE PLACE AHEAD OF THIS PHASING...
WITH GFS PRECIPITABLE WATER VALUES OF 1.25 INCHES SATURDAY NIGHT
NEAR THE 99TH PERCENTILE FOR EARLY MARCH. WOULD NOT BE SURPRISED
TO SEE OVER AN INCH OF RAIN IN SOME AREAS SATURDAY NIGHT THROUGH
SUNDAY NIGHT. HAVE INTRODUCED CATEGORICAL RAIN CHANCES SATURDAY
NIGHT NORTHWEST OF THE ILLINOIS RIVER...AND ALSO ADDED AREAS OF
FOG ACROSS THE NORTHERN CWA DUE TO THE HEAVIER RAIN AND RAPID SNOW
MELT. SUNDAY WILL START OUT RATHER WET AS WELL. HOWEVER...THE
MODELS BEGIN TO DIVERGE IN TERMS OF WHETHER A DRY SLOT MAY SPREAD
IN DURING THE DAY. WITH THE DIVERSITY...WILL NOT TRY TO GET TOO
CUTE WITH SPLITTING OUT MORNING AND AFTERNOON PERIODS.
TEMPERATURES BOTH DAYS SHOULD REACH WELL INTO THE 50S.
SUNDAY NIGHT AND MONDAY...THE GFS AND ECMWF MODELS BOTH SHOW THE
NORTHERN WAVE EXITING THE AREA...WHILE ANOTHER LOW DEVELOPS OVER
THE SOUTHERN PLAINS. THE GFS IS MORE AGGRESSIVE WITH CLOSING THIS
LOW OFF AND LIFTING IT NORTHEAST...WHILE THE ECMWF WEAKENS BACK
INTO AN OPEN WAVE. LEANING MORE TOWARD THE ECMWF SOLUTION FOR
NOW...AND HAVE LIMITED LIKELY POPS SUNDAY NIGHT TO THE SOUTHEAST
THIRD OF THE CWA. HAVE KEPT SOME PRECIP CHANCES IN ON MONDAY FOR
NOW...BUT CONFIDENCE IS LOW AT THE MOMENT. HAVE LARGELY KEPT THE
PRECIP AS RAIN EXCEPT FOR A MIX IN THE NORTHWEST.
MODEL AGREEMENT DOES NOT IMPROVE AS THE WEEK PROGRESSES...WITH THE
LONGER RANGE SOLUTIONS VARYING WITH THE STRENGTH OF ANOTHER WAVE
DROPPING INTO THE GREAT LAKES ON TUESDAY. THE ECMWF SOLUTION WOULD
BE MUCH COOLER FOR US WITH SIGNIFICANT RIDGING WEST OF THE
ROCKIES. FOR NOW HAVE KEPT TEMPERATURES ABOUT 5 DEGREES BELOW
NORMAL FOR THE END OF THE FORECAST PERIOD.
GEELHART
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
1127 AM CST THU MAR 7 2013
.DISCUSSION...
1006 AM CST
OTHER THAN A FEW TWEAKS TO HOURLY GRIDS...LITTLE/NO CHANGE TO GOING
FORECAST THIS MORNING. THIN BUT PERSISTENT LAYER OF STRATUS/STRATOCU
REMAINS ACROSS THE REGION...TRAPPED BENEATH STRONG INVERSION SEEN IN
THE 900-925 MB LAYER IN BOTH DVN AND ILX 12Z SOUNDINGS. WHILE SOME
CLEARING HAS OCCURRED OVER NORTHERN PARTS OF THE CHICAGO METRO AREA
AND LAKE MICHIGAN...CLOUDS ARE ACTUALLY SPREADING BACK NORTH ACROSS
EASTERN IA WEST OF THE LOW LEVEL HIGH PRESSURE RIDGE AXIS. DESPITE
BEING ABLE TO SEE TERRAIN FEATURES THROUGH THE THIN CLOUD LAYER ON
GOES VIS SATELLITE... SUSPECT THAT CLOUDS WILL BE HARD TO ERODE
TODAY. OTHER THAN A FEW PEEKS AT SOME BLUE SKY...MAINLY CLOUDY
CONDITIONS ARE EXPECTED. DEEP SNOW PACK AND THIN CLOUDY LAYER SHOULD
KEEP TEMPS IN CHECK WITHIN THE MID 30S OR SO.
RATZER
//PREV DISCUSSION...
330 AM CST
FORECAST CHALLENGES THIS MORNING INCLUDE CLOUDINESS THROUGH
TONIGHT...THEN THE BIG SLOPPY RAINY WET MELT DOWN EXPECTED THIS
WEEKEND.
STUBBORN STRATUS HAS NOT BUDGED AT ALL OVERNIGHT AND IS CURRENTLY
BLANKETING THE ENTIRE CWA. MODEL GUIDANCE IS NOT DOING A GREAT
JOB HANDLING CURRENT CONDITIONS WITH REGARDS TO THIS STRATUS DECK
WHICH LENDS ITSELF TO A LOWER CONFIDENCE FORECAST TODAY INTO
TONIGHT. RAP SEEMS TO HAVE THE BEST HANDLE ON LOW LEVEL RH AND IT
SUPPORTS WHAT I WAS THINKING WOULD HAPPEN CONCEPTUALLY WHICH IS
EROSION FROM THE EDGES COMMENCING AGAIN AFTER SUNRISE...ESPECIALLY
FROM THE SOUTHWEST WHERE SNOW PACK IS LESS OVER CENTRAL ILLINOIS.
RIDGE AXIS PASSING BY TODAY WILL THEN TURN LOW LEVEL EASTERLY
AND WHERE EVER THE EDGE OF THE STRATUS ENDS UP LATE THIS AFTERNOON
COULD SEE IT RE-DEVELOPING/RE-ADVECTING BACK WEST ACROSS THE CWA
TONIGHT. HUNCH IS THAT EASTERN CWA COULD STAY PRETTY SOCKED IN
TODAY WITH SOME CLEARING WEST THIS AFTERNOON BUT WITH POTENTIAL
FOR REDEVELOPMENT OF STRATUS TONIGHT. TRYING TO REFLECT THESE
TRENDS IN THE GRIDS IS GOING TO BE A CHALLENGE TO SAY THE LEAST...
TEMPS WILL BE HELD DOWN BY CLOUDS AND SNOW COVER TODAY...AND THEN
HELD UP TONIGHT WHERE STATUS ENDS UP PARKING. WESTERN CWA STANDS A
CHANCE OF SEEING CLEAR SKIES THIS EVENING AND A RAPID TEMP DROP.
GIVEN THE LIGHT WINDS THERE IS A POTENTIAL FOR SOME FREEZING
GROUND FOG DEVELOPING PRIOR TO THE ARRIVAL OF ANY STRATUS. ONCE
AGAIN TONIGHT LOW TEMPERATURE FORECAST IS VERY LOW CONFIDENCE WITH
ABOUT A 15-20F RANGE OF POSSIBLE LOWS...ESPECIALLY WESTERN CWA.
SAME DEAL FRIDAY...IF STRATUS DECK NEVER CLEARS OUT THEN CLOUDY
START WITH POSSIBLE SCATTERING OUT IN THE AFTERNOON WOULD BE
EXPECTED WITH COLDER TEMPS. CONVERSELY...SHOULD THE STRATUS BE
GONE SUNNY SKIES WITH HIGHER SUN ANGLE MARCH SUN COULD RESULT IN
FRIDAY TURNING INTO DAY 1 OF THE GREAT MELT DOWN WITH HIGHS
GETTING WELL INTO THE 30S AND MAYBE LOW 40S IN SOUTHERN CWA AND IN
MORE URBANIZED AREAS.
WEEKEND FORECAST STILL GENERALLY LOOKS ON TRACK...THOUGH MODELS HAVE
TRENDED TOWARD A SLIGHTLY WEAKER/LESS PHASED SOLUTION WOULD MEAN A
SOMEWHAT LESSER THREAT OF HEAVY RAINFALL. WE ARE STILL PRETTY FAR
OUT IN TIME AND WOULD ANTICIPATE MORE CHANGES IN FORECAST GUIDANCE
THE NEXT COUPLE DAYS...MOST LIKELY TO SLOW THE SYSTEM DOWN IF
ANYTHING...SO NOT GOING TO MAKE ANY BIG CHANGES TO GOING FORECAST
FOR THE WEEKEND. EARLY NEXT WEEK THE RUNS DE JOUR OF THE MEDIUM
RANGE GUIDANCE LOOKS LESS FOREBODING REGARDING A SNOW SYSTEM WITH A
LESS PHASED MORE POSITIVELY TILTED/PROGRESSIVE TROUGH MOVING THROUGH
BUT STILL PLENTY OF TIME FOR THAT TO CHANGE SO PROBABLY A LITTLE
PREMATURE TO PUT AWAY THE SHOVELS FOR THE YEAR YET.
IZZI
&&
.HYDROLOGY...
330 AM CST
DEEP WATER LOGGED SNOW PACK BLANKETS THE CWA WITH SNOW WATER
EQUIV`S NEAR TO OVER AN INCH OVER NORTHERN HALF OF THE CWA. RISING
TEMPS AND DEWPOINTS THIS WEEKEND SHOULD RESULT IN AN INCREASING
QUICK MELTING OF THE SNOW PACK...WITH ANY RAIN FALLING ON TOP OF
IT SERVING TO FURTHER INCREASE THE CHANCE OF SOME FLOODING
PROBLEMS DEVELOPING. CONFIDENCE IN RAINFALL TOTALS THIS WEEKEND
NOT OVERLY HIGH...BUT EARLY BALL PARK NUMBERS IN THE HALF INCH TO
ONE INCH RANGE LOOK QUITE PLAUSIBLE AND SUFFICIENT FOR SIGNIFICANT
RISES ON AREA RIVERS AND POTENTIAL FOR FLOODING. WILL CONTINUE TO
HIGHLIGHT THREAT IN THE HWO AND DAY SHIFT MAY NEED TO CONSIDER AN
ESF.
IZZI
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 18Z...
* SLIGHT CHANCE FOR VIS RESTRICTIONS IN BR EARLY FRIDAY MORNING.
KREIN
//DISCUSSION...UPDATED 18Z...
MAIN ISSUE FOR THE REMAINDER OF THE AFTERNOON AND INTO THIS
EVENING WILL BE CEILINGS. THE LOWER END VFR STRATOCU DECK REMAINS
IN PLACE OVER MUCH OF THE AREA...LOWERING TO HIGH END MVFR CIGS
WEST OF THE CHICAGO AREA INCLUDING RFD. A CLEARING SLOT HAD PUSHED
SOUTH OVER FAR NERN IL THIS MORNING...ALLOWING ORD TO BRIEFLY
IMPROVE TO SCT035...BUT THE STRATOCU HAS FILLED BACK TO BKN-
OVC035. WHILE THE LATEST VISIBLE SATELLITE IMAGERY INDICATES THAT
THE CLOUD IS VERY THIN...WITH SFC FEATURES SHOWING THROUGH THE
CLOUD COVER...THE 11-3.9 MICRON IMAGERY MUCH BETTER SHOWS THE
EXTENT OF THE CLOUD COVER...WITH LATEST TRENDS INDICATING NO
TREND OF CLOUD COVER TO IMPROVE. ALSO...MODEL SOUNDING CONTINUE TO
INDICATE A WEAK INVERSION IN PLACE THROUGH THE AFTERNOON AND THIS
EVENING...SO DO NOT EXPECT ANY DEEP LAYER MIXING TO HELP BREAK UP
THE CLOUD COVER. WITH THE SFC RIDGE MOVING ACROSS THE
AREA...EXPECT THAT WINDS WILL BE LGT/VRBL TO CALM THROUGH MUCH OF
THE PERIOD...BEFORE BECOMING MORE SELY AND STRENGTHENING TOMORROW
MORNING AS THE SFC RIDGE PUSHES TO THE EAST. HAVE SOME CONCERN FOR
REDUCED VISBY IN BR/FG OVERNIGHT TONIGHT WITH LIGHT WINDS AND
DECREASING CLOUD COVER. HOWEVER...CONFIDENCE IS NOT HIGH IN THE
CLOUD COVER TRENDS. ALSO...SFC DEWPOINTS ARE EXPECTED TO REMAIN
FAIRLY LOW...SO DO NOT HAVE HIGH ENOUGH CONFIDENCE IN THE
POTENTIAL FOR REDUCED VISBY TONIGHT TO INCLUDE IN THE TAFS JUST
YET.
LOOKING AHEAD TO THIS WEEKEND...LOOKING AT THE POTENTIAL FOR
WIDESPREAD FOG DEVELOPMENT AS STRONG MOIST ADVECTION DRIVES
DEWPOINTS INTO THE 30S AND EVENTUALLY 40S OVER DEEP SNOW PACK. THIS
TYPE OF SETUP HAS THE POTENTIAL FOR PRODUCING WIDESPREAD AND
POTENTIALLY DENSE FOG.
KREIN
//ORD AND MDW CONFIDENCE...UPDATED 18Z...
* LOW CONFIDENCE ON TIMING SCATTERING OF THE STRATOCU DECK...AND
THE POTENTIAL FOR BR/FG LATE TONIGHT INTO EARLY TOMORROW
MORNING.
* MEDIUM TO HIGH CONFIDENCE IN ALL OTHER FORECAST ELEMENTS.
KREIN
//OUTLOOK FOR ORD/MDW FOR 00Z SATURDAY-12Z THURSDAY...UPDATED 12Z...
FRIDAY NIGHT THROUGH SATURDAY...VFR.
SATURDAY NIGHT THROUGH SUNDAY...RAIN/FOG.
MONDAY...CHC RAIN/SNOW.
TUESDAY THROUGH WEDNESDAY...VFR.
BMD
&&
.MARINE...
311 AM CST
MAIN CONCERN THIS FORECAST PACKAGE WILL BE WINDS INCREASING BEHIND
AN AREA OF LOW PRESSURE EARLY NEXT WEEK. SHOULD BE A QUIET END OF
THE WORK WEEK WITH HIGH PRESSURE BUILDING ACROSS LAKE MICHIGAN TODAY
ALLOWING WINDS AND SUBSEQUENT WAVES TO DIMINISH. WILL ALLOW THE
SMALL CRAFT ADVISORY TO EXPIRE WITH THE MORNING NSH ISSUANCE.
SOUTHERLY WINDS FRESHEN SOME OVER THE WEEKEND AS LOW PRESSURE TAKES
SHAPE OVER THE PLAINS...BUT MAIN CONCERN WILL BE BEHIND THE LOW AS
EARLY AS SUNDAY NIGHT WHEN NORTHERLY WINDS ARE EXPECTED TO RAMP UP
TO AROUND 30 KT. THESE WINDS SHOULD CONTINUE THROUGH THE DAY MONDAY.
MODELS ARE STRUGGLING WITH THE DETAILS OF THIS SYSTEM...INCLUDING
HOW STRONG AND WELL ORGANIZED IT WILL BECOME...BUT GENERALLY
SUGGEST A BROAD TROUGH ACROSS THE AREA WITH TWO DISTINCT WAVES
DEVELOPING. DEPENDING ON HOW IT PANS OUT THERE MAY BE SLIGHTLY
STRONGER WINDS //LOW END GALES// WITH A BETTER DEVELOPED LOW OR
OVERALL WINDS MAY BE SLIGHTLY WEAKER BUT STAY ELEVATED FOR A LONGER
TIME PERIOD WITH A LESS ORGANIZED WAVE. WILL HAVE TO MAKE
ADJUSTMENTS AS MODELS LOCK ONTO A PARTICULAR SOLUTION IN THE COMING
DAYS. EITHER WAY...WINDS SHOULD BEGIN TO TAPER AGAIN MIDWEEK AS
ANOTHER RIDGE BEGINS TO BUILD INTO THE WESTERN GREAT LAKES REGION.
BMD
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
1007 AM CST THU MAR 7 2013
.DISCUSSION...
1006 AM CST
OTHER THAN A FEW TWEAKS TO HOURLY GRIDS...LITTLE/NO CHANGE TO GOING
FORECAST THIS MORNING. THIN BUT PERSISTENT LAYER OF STRATUS/STRATOCU
REMAINS ACROSS THE REGION...TRAPPED BENEATH STRONG INVERSION SEEN IN
THE 900-925 MB LAYER IN BOTH DVN AND ILX 12Z SOUNDINGS. WHILE SOME
CLEARING HAS OCCURRED OVER NORTHERN PARTS OF THE CHICAGO METRO AREA
AND LAKE MICHIGAN...CLOUDS ARE ACTUALLY SPREADING BACK NORTH ACROSS
EASTERN IA WEST OF THE LOW LEVEL HIGH PRESSURE RIDGE AXIS. DESPITE
BEING ABLE TO SEE TERRAIN FEATURES THROUGH THE THIN CLOUD LAYER ON
GOES VIS SATELLITE... SUSPECT THAT CLOUDS WILL BE HARD TO ERODE
TODAY. OTHER THAN A FEW PEEKS AT SOME BLUE SKY...MAINLY CLOUDY
CONDITIONS ARE EXPECTED. DEEP SNOW PACK AND THIN CLOUDY LAYER SHOULD
KEEP TEMPS IN CHECK WITHIN THE MID 30S OR SO.
RATZER
&&
.PREV DISCUSSION...
330 AM CST
FORECAST CHALLENGES THIS MORNING INCLUDE CLOUDINESS THROUGH
TONIGHT...THEN THE BIG SLOPPY RAINY WET MELT DOWN EXPECTED THIS
WEEKEND.
STUBBORN STRATUS HAS NOT BUDGED AT ALL OVERNIGHT AND IS CURRENTLY
BLANKETING THE ENTIRE CWA. MODEL GUIDANCE IS NOT DOING A GREAT
JOB HANDLING CURRENT CONDITIONS WITH REGARDS TO THIS STRATUS DECK
WHICH LENDS ITSELF TO A LOWER CONFIDENCE FORECAST TODAY INTO
TONIGHT. RAP SEEMS TO HAVE THE BEST HANDLE ON LOW LEVEL RH AND IT
SUPPORTS WHAT I WAS THINKING WOULD HAPPEN CONCEPTUALLY WHICH IS
EROSION FROM THE EDGES COMMENCING AGAIN AFTER SUNRISE...ESPECIALLY
FROM THE SOUTHWEST WHERE SNOW PACK IS LESS OVER CENTRAL ILLINOIS.
RIDGE AXIS PASSING BY TODAY WILL THEN TURN LOW LEVEL EASTERLY
AND WHERE EVER THE EDGE OF THE STRATUS ENDS UP LATE THIS AFTERNOON
COULD SEE IT RE-DEVELOPING/RE-ADVECTING BACK WEST ACROSS THE CWA
TONIGHT. HUNCH IS THAT EASTERN CWA COULD STAY PRETTY SOCKED IN
TODAY WITH SOME CLEARING WEST THIS AFTERNOON BUT WITH POTENTIAL
FOR REDEVELOPMENT OF STRATUS TONIGHT. TRYING TO REFLECT THESE
TRENDS IN THE GRIDS IS GOING TO BE A CHALLENGE TO SAY THE LEAST...
TEMPS WILL BE HELD DOWN BY CLOUDS AND SNOW COVER TODAY...AND THEN
HELD UP TONIGHT WHERE STATUS ENDS UP PARKING. WESTERN CWA STANDS A
CHANCE OF SEEING CLEAR SKIES THIS EVENING AND A RAPID TEMP DROP.
GIVEN THE LIGHT WINDS THERE IS A POTENTIAL FOR SOME FREEZING
GROUND FOG DEVELOPING PRIOR TO THE ARRIVAL OF ANY STRATUS. ONCE
AGAIN TONIGHT LOW TEMPERATURE FORECAST IS VERY LOW CONFIDENCE WITH
ABOUT A 15-20F RANGE OF POSSIBLE LOWS...ESPECIALLY WESTERN CWA.
SAME DEAL FRIDAY...IF STRATUS DECK NEVER CLEARS OUT THEN CLOUDY
START WITH POSSIBLE SCATTERING OUT IN THE AFTERNOON WOULD BE
EXPECTED WITH COLDER TEMPS. CONVERSELY...SHOULD THE STRATUS BE
GONE SUNNY SKIES WITH HIGHER SUN ANGLE MARCH SUN COULD RESULT IN
FRIDAY TURNING INTO DAY 1 OF THE GREAT MELT DOWN WITH HIGHS
GETTING WELL INTO THE 30S AND MAYBE LOW 40S IN SOUTHERN CWA AND IN
MORE URBANIZED AREAS.
WEEKEND FORECAST STILL GENERALLY LOOKS ON TRACK...THOUGH MODELS HAVE
TRENDED TOWARD A SLIGHTLY WEAKER/LESS PHASED SOLUTION WOULD MEAN A
SOMEWHAT LESSER THREAT OF HEAVY RAINFALL. WE ARE STILL PRETTY FAR
OUT IN TIME AND WOULD ANTICIPATE MORE CHANGES IN FORECAST GUIDANCE
THE NEXT COUPLE DAYS...MOST LIKELY TO SLOW THE SYSTEM DOWN IF
ANYTHING...SO NOT GOING TO MAKE ANY BIG CHANGES TO GOING FORECAST
FOR THE WEEKEND. EARLY NEXT WEEK THE RUNS DE JOUR OF THE MEDIUM
RANGE GUIDANCE LOOKS LESS FOREBODING REGARDING A SNOW SYSTEM WITH A
LESS PHASED MORE POSITIVELY TILTED/PROGRESSIVE TROUGH MOVING THROUGH
BUT STILL PLENTY OF TIME FOR THAT TO CHANGE SO PROBABLY A LITTLE
PREMATURE TO PUT AWAY THE SHOVELS FOR THE YEAR YET.
IZZI
&&
.HYDROLOGY...
330 AM CST
DEEP WATER LOGGED SNOW PACK BLANKETS THE CWA WITH SNOW WATER
EQUIV`S NEAR TO OVER AN INCH OVER NORTHERN HALF OF THE CWA. RISING
TEMPS AND DEWPOINTS THIS WEEKEND SHOULD RESULT IN AN INCREASING
QUICK MELTING OF THE SNOW PACK...WITH ANY RAIN FALLING ON TOP OF
IT SERVING TO FURTHER INCREASE THE CHANCE OF SOME FLOODING
PROBLEMS DEVELOPING. CONFIDENCE IN RAINFALL TOTALS THIS WEEKEND
NOT OVERLY HIGH...BUT EARLY BALL PARK NUMBERS IN THE HALF INCH TO
ONE INCH RANGE LOOK QUITE PLAUSIBLE AND SUFFICIENT FOR SIGNIFICANT
RISES ON AREA RIVERS AND POTENTIAL FOR FLOODING. WILL CONTINUE TO
HIGHLIGHT THREAT IN THE HWO AND DAY SHIFT MAY NEED TO CONSIDER AN
ESF.
IZZI
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 16Z...
* POTENTIAL FOR FOG FRIDAY MORNING.
KREIN
//DISCUSSION...UPDATED 12Z...
VFR STRATUS DECK REMAINS IN PLACE OVER THE CHICAGO AREA WITH HIGH
END MVFR CIGS WEST OF THE CHICAGO AREA INCLUDING RFD. GUIDANCE IS
NOT HANDLING THE SITUATION WELL NOR HOW LONG TO HANG ONTO THE CIGS
THROUGH THE DAY. HAVE TRENDED SLOWER WITH CLEARING AS COLD BOUNDARY
LAYER UNDERNEATH A MODERATE INVERSION MAY KEEP MOISTURE LOCKED IN
THROUGH THE DAY. THERE IS SUBTLE COOLING NOTED AT 925MB THIS
AFTERNOON WHICH MODEL SOUNDINGS SUGGEST MAY LEAD TO LOWERING MVFR
CIGS AROUND 020...HOWEVER THINK THE MODELS ARE LIKELY OVERDOING THE
DIURNAL HEATING COMPONENT TODAY AND RESULTANT LAPSE RATES...AND
DO NOT HAVE CONFIDENCE IN THIS SCENARIO PANNING OUT. WILL STICK WITH
SCT020 IN THE MEANTIME. WINDS ARE EXPECTED TO REMAIN LESS THAN 10 KT
THROUGH THE DAY...AND SHOULD GRADUALLY VEER FROM NW THIS MORNING TO
EASTERLY OVERNIGHT.
IN THE EVENT WE DO CLEAR OUT TODAY...WILL THEN HAVE TO KEEP AN EYE
ON THE FOG POTENTIAL. CONCEPTUALLY...LIGHT WINDS CLOSE TO THE RIDGE
AXIS...PERHAPS SOME ADDITIONAL BL MOISTURE WITH TEMPS PEAKING ABOVE
FREEZING THIS AFTERNOON HELPING TO MELT SOME OF THE SNOW...AND CLEAR
SKIES/FRESH SNOW SHOULD ALL LEAD TO STRONG RADIATIONAL COOLING AND
ENHANCED FOG POTENTIAL. DENSE FOG WAS OBSERVED OVERNIGHT TO OUR
WEST. BUT FOR NOW...BANKING ON CLOUDY SKIES STICKING AROUND TODAY
MINIMIZING THE FOG THREAT.
LOOKING AHEAD TO THIS WEEKEND...LOOKING AT THE POTENTIAL FOR
WIDESPREAD FOG DEVELOPMENT AS STRONG MOIST ADVECTION DRIVES
DEWPOINTS INTO THE 30S AND EVENTUALLY 40S OVER DEEP SNOWPACK. THIS
TYPE OF SETUP HAS THE POTENTIAL FOR PRODUCING WIDESPREAD AND
POTENTIALLY DENSE FOG.
BMD
//ORD AND MDW CONFIDENCE...UPDATED 16Z...
* LOW CONFIDENCE ON TIMING CLEARING OF VFR CIGS...AND RESULTING
FOG POTENTIAL OVERNIGHT.
* MMEDIUM TO HIGH CONFIDENCE IN ALL OTHER FORECAST ELEMENTS.
KREIN
//OUTLOOK FOR ORD/MDW FOR 00Z SATURDAY-12Z THURSDAY...UPDATED 12Z...
FRIDAY NIGHT THROUGH SATURDAY...VFR.
SATURDAY NIGHT THROUGH SUNDAY...RAIN/FOG.
MONDAY...CHC RAIN/SNOW.
TUESDAY THROUGH WEDNESDAY...VFR.
BMD
&&
.MARINE...
311 AM CST
MAIN CONCERN THIS FORECAST PACKAGE WILL BE WINDS INCREASING BEHIND
AN AREA OF LOW PRESSURE EARLY NEXT WEEK. SHOULD BE A QUIET END OF
THE WORK WEEK WITH HIGH PRESSURE BUILDING ACROSS LAKE MICHIGAN TODAY
ALLOWING WINDS AND SUBSEQUENT WAVES TO DIMINISH. WILL ALLOW THE
SMALL CRAFT ADVISORY TO EXPIRE WITH THE MORNING NSH ISSUANCE.
SOUTHERLY WINDS FRESHEN SOME OVER THE WEEKEND AS LOW PRESSURE TAKES
SHAPE OVER THE PLAINS...BUT MAIN CONCERN WILL BE BEHIND THE LOW AS
EARLY AS SUNDAY NIGHT WHEN NORTHERLY WINDS ARE EXPECTED TO RAMP UP
TO AROUND 30 KT. THESE WINDS SHOULD CONTINUE THROUGH THE DAY MONDAY.
MODELS ARE STRUGGLING WITH THE DETAILS OF THIS SYSTEM...INCLUDING
HOW STRONG AND WELL ORGANIZED IT WILL BECOME...BUT GENERALLY
SUGGEST A BROAD TROUGH ACROSS THE AREA WITH TWO DISTINCT WAVES
DEVELOPING. DEPENDING ON HOW IT PANS OUT THERE MAY BE SLIGHTLY
STRONGER WINDS //LOW END GALES// WITH A BETTER DEVELOPED LOW OR
OVERALL WINDS MAY BE SLIGHTLY WEAKER BUT STAY ELEVATED FOR A LONGER
TIME PERIOD WITH A LESS ORGANIZED WAVE. WILL HAVE TO MAKE
ADJUSTMENTS AS MODELS LOCK ONTO A PARTICULAR SOLUTION IN THE COMING
DAYS. EITHER WAY...WINDS SHOULD BEGIN TO TAPER AGAIN MIDWEEK AS
ANOTHER RIDGE BEGINS TO BUILD INTO THE WESTERN GREAT LAKES REGION.
BMD
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS LINCOLN IL
951 AM CST THU MAR 7 2013
.DISCUSSION...
ISSUED 951 AM CST THU MAR 7 2013
CLOUDS CONTINUE TO PLAGUE CENTRAL AND SOUTHEAST ILLINOIS THIS
MORNING...THANKS TO MOISTURE TRAPPED BENEATH A STRONG LOW-LEVEL
SUBSIDENCE INVERSION. LATEST VISIBLE SATELLITE IMAGERY SHOWS A
RATHER THIN OVERCAST ACROSS THE REGION...WITH MAJOR RIVERS DIMLY
VISIBLE THROUGH THE CLOUD COVER. GIVEN RELATIVE THINNESS OF CLOUDS
AND STRENGTH OF EARLY MARCH SUN...THINK A FEW HOLES WILL BE
PUNCHED IN THE OVERCAST AS THE DAY GOES ON. HOWEVER...WITH STRONG
INVERSION IN PLACE AND LITTLE OR NO WIND...EXPECT GENERALLY CLOUDY
CONDITIONS THROUGH THE DAY. WINDS WILL BECOME LIGHT AND EASTERLY
LATER TODAY/TONIGHT...AS SURFACE HIGH SHIFTS INTO THE OHIO RIVER
VALLEY. THIS MAY TEND TO ADVECT LOW-LEVEL MOISTURE BACK INTO THE
AREA TONIGHT. WHILE 12Z NAM FORECAST SOUNDINGS INDICATE CLEARING
BY EVENING...14Z RUC SOUNDINGS MAY HAVE A BETTER HANDLE ON
REALITY...INDICATING MOSTLY CLOUDY CONDITIONS PERSISTING THROUGH
THE NIGHT.
BARNES
&&
.AVIATION...
ISSUED 556 AM CST THU MAR 7 2013
A PESKY AREA OF MVFR STRATUS/STRATO CUMULUS CONTINUES TO PLAGUE
THE CENTRAL ILLINOIS TERMINALS. IN FACT...THE AREAL COVERAGE OF
THE CLOUDS HAS EXPANDED SOME OVERNIGHT. EXPECT THE EDGES OF THE
CLOUDS TO ERODE TODAY...WITH SKIES POSSIBLY SCATTERING OUT BY THIS
EVENING. HOWEVER...THERE IS THE POTENTIAL THE THE CLOUDS WILL HANG
ON EVEN LONGER AS THERE IS A STRONG LOW LEVEL INVERSION TO TRAP
MOISTURE...AND LOW LEVEL WINDS ARE TOO WEAK TO EFFECTIVELY SCOUR
THE CLOUDS OUT. IN FACT...THE LOW LEVEL FLOW TURNS EASTERLY
TONIGHT AND MAY ACT TO BLOW CLOUDS BACK WEST INTO THE AREA AFTER
CLEARING HAS TAKEN PLACE OVERHEAD.
BAK
&&
.PREV DISCUSSION...
ISSUED 307 AM CST THU MAR 7 2013
EARLY MORNING SURFACE MAP SHOWED HIGH PRESSURE RIDGING RUNNING THE
LENGTH OF THE MISSISSIPPI RIVER. RATHER TIGHT INVERSION JUST ABOVE
900 MB HAS PUT THE KIBOSH ON ANY REAL EROSION OF THE LARGE
STRATOCUMULUS DECK OVER MUCH OF THE MIDWEST...WITH ONLY AREAS
AROUND JACKSONVILLE SEEING ANY SUSTAINED CLEARING AND THAT HAS
BEGUN TO FILL IN AS WELL. THE CLOUDS HAVE KEPT TEMPERATURES IN THE
20S...WHICH IS GOOD SINCE CLEAR SKIES OVER THE SUBSTANTIAL SNOW
COVER IN THE NORTHERN CWA WOULD HAVE LIKELY RESULTED IN SINGLE
DIGITS AND TEENS IN THAT AREA. LOOKING UPSTAIRS...LATEST WATER
VAPOR IMAGERY SHOWING SEVERAL CIRCULATIONS IN A BROAD AREA OF 500
MB LOW PRESSURE OVER THE PACIFIC NORTHWEST. DEVELOPMENT OF THIS
PARTICULAR FEATURE WILL BE OF INTEREST TO OUR FORECAST FOR THE
WEEKEND.
SHORT TERM...TODAY THROUGH FRIDAY...
FAIRLY QUIET WEATHER EXPECTED IN THE SHORT TERM...AS THE HIGH
PUSHES EAST ACROSS THE GREAT LAKES. FORECAST SOUNDINGS SHOW THE
INVERSION SLOW TO ERODE THOUGH...SO WILL KEEP THE EASTERN CWA
FAIRLY CLOUDY TODAY AND TRY TO MARK SOME CLEARING ACROSS THE WEST
BY MIDDAY. MAIN CONCERN WILL BE WITH FOG POTENTIAL TONIGHT ACROSS
THE NORTH...WITH WINDS STILL FAIRLY LIGHT AND SOME POTENTIAL FOR
SNOW MELT TODAY. SHOULD SKIES STAY CLOUDY...THIS WOULD BE LESS OF
A CONCERN.
TEMPERATURE-WISE...WILL CONTINUE THE TREND OF KEEPING HIGHS A FEW
DEGREES COOLER ACROSS THE NORTH WHERE THE SNOW DEPTH RANGES FROM 5
TO 9 INCHES. HOWEVER...EVEN THESE AREAS MAY CRACK 40 BY FRIDAY...
WITH HIGHS 45-50 FURTHER SOUTH.
LONG TERM...SATURDAY THROUGH WEDNESDAY...
UPPER LOW IN THE PACIFIC NORTHWEST SHOULD BETTER ORGANIZE AS IT
DROPS SOUTHWARD ALONG THE CALIFORNIA COAST TONIGHT AND FRIDAY.
LATEST MODEL GUIDANCE CONTINUES TO EJECT THIS FEATURE NORTHEAST
THIS WEEKEND...AS A DEEPENING SHORTWAVE TRACKS EAST ACROSS THE
CANADIAN PRAIRIES. SOME PHASING OF THE TWO FEATURES IS INDICATED
LATER THIS WEEKEND OVER THE CENTRAL U.S. AND THIS WILL
SIGNIFICANTLY INCREASE PRECIP CHANCES AS THE WEEKEND PROGRESSES.
GOOD MOISTURE SURGE SHOULD TAKE PLACE AHEAD OF THIS PHASING...
WITH GFS PRECIPITABLE WATER VALUES OF 1.25 INCHES SATURDAY NIGHT
NEAR THE 99TH PERCENTILE FOR EARLY MARCH. WOULD NOT BE SURPRISED
TO SEE OVER AN INCH OF RAIN IN SOME AREAS SATURDAY NIGHT THROUGH
SUNDAY NIGHT. HAVE INTRODUCED CATEGORICAL RAIN CHANCES SATURDAY
NIGHT NORTHWEST OF THE ILLINOIS RIVER...AND ALSO ADDED AREAS OF
FOG ACROSS THE NORTHERN CWA DUE TO THE HEAVIER RAIN AND RAPID SNOW
MELT. SUNDAY WILL START OUT RATHER WET AS WELL. HOWEVER...THE
MODELS BEGIN TO DIVERGE IN TERMS OF WHETHER A DRY SLOT MAY SPREAD
IN DURING THE DAY. WITH THE DIVERSITY...WILL NOT TRY TO GET TOO
CUTE WITH SPLITTING OUT MORNING AND AFTERNOON PERIODS.
TEMPERATURES BOTH DAYS SHOULD REACH WELL INTO THE 50S.
SUNDAY NIGHT AND MONDAY...THE GFS AND ECMWF MODELS BOTH SHOW THE
NORTHERN WAVE EXITING THE AREA...WHILE ANOTHER LOW DEVELOPS OVER
THE SOUTHERN PLAINS. THE GFS IS MORE AGGRESSIVE WITH CLOSING THIS
LOW OFF AND LIFTING IT NORTHEAST...WHILE THE ECMWF WEAKENS BACK
INTO AN OPEN WAVE. LEANING MORE TOWARD THE ECMWF SOLUTION FOR
NOW...AND HAVE LIMITED LIKELY POPS SUNDAY NIGHT TO THE SOUTHEAST
THIRD OF THE CWA. HAVE KEPT SOME PRECIP CHANCES IN ON MONDAY FOR
NOW...BUT CONFIDENCE IS LOW AT THE MOMENT. HAVE LARGELY KEPT THE
PRECIP AS RAIN EXCEPT FOR A MIX IN THE NORTHWEST.
MODEL AGREEMENT DOES NOT IMPROVE AS THE WEEK PROGRESSES...WITH THE
LONGER RANGE SOLUTIONS VARYING WITH THE STRENGTH OF ANOTHER WAVE
DROPPING INTO THE GREAT LAKES ON TUESDAY. THE ECMWF SOLUTION WOULD
BE MUCH COOLER FOR US WITH SIGNIFICANT RIDGING WEST OF THE
ROCKIES. FOR NOW HAVE KEPT TEMPERATURES ABOUT 5 DEGREES BELOW
NORMAL FOR THE END OF THE FORECAST PERIOD.
GEELHART
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
815 AM CST THU MAR 7 2013
.DISCUSSION...
330 AM CST
FORECAST CHALLENGES THIS MORNING INCLUDE CLOUDINESS THROUGH
TONIGHT...THEN THE BIG SLOPPY RAINY WET MELT DOWN EXPECTED THIS
WEEKEND.
STUBBORN STRATUS HAS NOT BUDGED AT ALL OVERNIGHT AND IS CURRENTLY
BLANKETING THE ENTIRE CWA. MODEL GUIDANCE IS NOT DOING A GREAT
JOB HANDLING CURRENT CONDITIONS WITH REGARDS TO THIS STRATUS DECK
WHICH LENDS ITSELF TO A LOWER CONFIDENCE FORECAST TODAY INTO
TONIGHT. RAP SEEMS TO HAVE THE BEST HANDLE ON LOW LEVEL RH AND IT
SUPPORTS WHAT I WAS THINKING WOULD HAPPEN CONCEPTUALLY WHICH IS
EROSION FROM THE EDGES COMMENCING AGAIN AFTER SUNRISE...ESPECIALLY
FROM THE SOUTHWEST WHERE SNOW PACK IS LESS OVER CENTRAL ILLINOIS.
RIDGE AXIS PASSING BY TODAY WILL THEN TURN LOW LEVEL EASTERLY
AND WHERE EVER THE EDGE OF THE STRATUS ENDS UP LATE THIS AFTERNOON
COULD SEE IT RE-DEVELOPING/RE-ADVECTING BACK WEST ACROSS THE CWA
TONIGHT. HUNCH IS THAT EASTERN CWA COULD STAY PRETTY SOCKED IN
TODAY WITH SOME CLEARING WEST THIS AFTERNOON BUT WITH POTENTIAL
FOR REDEVELOPMENT OF STRATUS TONIGHT. TRYING TO REFLECT THESE
TRENDS IN THE GRIDS IS GOING TO BE A CHALLENGE TO SAY THE LEAST...
TEMPS WILL BE HELD DOWN BY CLOUDS AND SNOW COVER TODAY...AND THEN
HELD UP TONIGHT WHERE STATUS ENDS UP PARKING. WESTERN CWA STANDS A
CHANCE OF SEEING CLEAR SKIES THIS EVENING AND A RAPID TEMP DROP.
GIVEN THE LIGHT WINDS THERE IS A POTENTIAL FOR SOME FREEZING
GROUND FOG DEVELOPING PRIOR TO THE ARRIVAL OF ANY STRATUS. ONCE
AGAIN TONIGHT LOW TEMPERATURE FORECAST IS VERY LOW CONFIDENCE WITH
ABOUT A 15-20F RANGE OF POSSIBLE LOWS...ESPECIALLY WESTERN CWA.
SAME DEAL FRIDAY...IF STRATUS DECK NEVER CLEARS OUT THEN CLOUDY
START WITH POSSIBLE SCATTERING OUT IN THE AFTERNOON WOULD BE
EXPECTED WITH COLDER TEMPS. CONVERSELY...SHOULD THE STRATUS BE
GONE SUNNY SKIES WITH HIGHER SUN ANGLE MARCH SUN COULD RESULT IN
FRIDAY TURNING INTO DAY 1 OF THE GREAT MELT DOWN WITH HIGHS
GETTING WELL INTO THE 30S AND MAYBE LOW 40S IN SOUTHERN CWA AND IN
MORE URBANIZED AREAS.
WEEKEND FORECAST STILL GENERALLY LOOKS ON TRACK...THOUGH MODELS HAVE
TRENDED TOWARD A SLIGHTLY WEAKER/LESS PHASED SOLUTION WOULD MEAN A
SOMEWHAT LESSER THREAT OF HEAVY RAINFALL. WE ARE STILL PRETTY FAR
OUT IN TIME AND WOULD ANTICIPATE MORE CHANGES IN FORECAST GUIDANCE
THE NEXT COUPLE DAYS...MOST LIKELY TO SLOW THE SYSTEM DOWN IF
ANYTHING...SO NOT GOING TO MAKE ANY BIG CHANGES TO GOING FORECAST
FOR THE WEEKEND. EARLY NEXT WEEK THE RUNS DE JOUR OF THE MEDIUM
RANGE GUIDANCE LOOKS LESS FOREBODING REGARDING A SNOW SYSTEM WITH A
LESS PHASED MORE POSITIVELY TILTED/PROGRESSIVE TROUGH MOVING THROUGH
BUT STILL PLENTY OF TIME FOR THAT TO CHANGE SO PROBABLY A LITTLE
PREMATURE TO PUT AWAY THE SHOVELS FOR THE YEAR YET.
IZZI
&&
.HYDROLOGY...
330 AM CST
DEEP WATER LOGGED SNOW PACK BLANKETS THE CWA WITH SNOW WATER
EQUIV`S NEAR TO OVER AN INCH OVER NORTHERN HALF OF THE CWA. RISING
TEMPS AND DEWPOINTS THIS WEEKEND SHOULD RESULT IN AN INCREASING
QUICK MELTING OF THE SNOW PACK...WITH ANY RAIN FALLING ON TOP OF
IT SERVING TO FURTHER INCREASE THE CHANCE OF SOME FLOODING
PROBLEMS DEVELOPING. CONFIDENCE IN RAINFALL TOTALS THIS WEEKEND
NOT OVERLY HIGH...BUT EARLY BALL PARK NUMBERS IN THE HALF INCH TO
ONE INCH RANGE LOOK QUITE PLAUSIBLE AND SUFFICIENT FOR SIGNIFICANT
RISES ON AREA RIVERS AND POTENTIAL FOR FLOODING. WILL CONTINUE TO
HIGHLIGHT THREAT IN THE HWO AND DAY SHIFT MAY NEED TO CONSIDER AN
ESF.
IZZI
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 14Z...
* POTENTIAL FOR FOG FRIDAY MORNING.
KREIN
//DISCUSSION...UPDATED 12Z...
VFR STRATUS DECK REMAINS IN PLACE OVER THE CHICAGO AREA WITH HIGH
END MVFR CIGS WEST OF THE CHICAGO AREA INCLUDING RFD. GUIDANCE IS
NOT HANDLING THE SITUATION WELL NOR HOW LONG TO HANG ONTO THE CIGS
THROUGH THE DAY. HAVE TRENDED SLOWER WITH CLEARING AS COLD BOUNDARY
LAYER UNDERNEATH A MODERATE INVERSION MAY KEEP MOISTURE LOCKED IN
THROUGH THE DAY. THERE IS SUBTLE COOLING NOTED AT 925MB THIS
AFTERNOON WHICH MODEL SOUNDINGS SUGGEST MAY LEAD TO LOWERING MVFR
CIGS AROUND 020...HOWEVER THINK THE MODELS ARE LIKELY OVERDOING THE
DIURNAL HEATING COMPONENT TODAY AND RESULTANT LAPSE RATES...AND
DO NOT HAVE CONFIDENCE IN THIS SCENARIO PANNING OUT. WILL STICK WITH
SCT020 IN THE MEANTIME. WINDS ARE EXPECTED TO REMAIN LESS THAN 10 KT
THROUGH THE DAY...AND SHOULD GRADUALLY VEER FROM NW THIS MORNING TO
EASTERLY OVERNIGHT.
IN THE EVENT WE DO CLEAR OUT TODAY...WILL THEN HAVE TO KEEP AN EYE
ON THE FOG POTENTIAL. CONCEPTUALLY...LIGHT WINDS CLOSE TO THE RIDGE
AXIS...PERHAPS SOME ADDITIONAL BL MOISTURE WITH TEMPS PEAKING ABOVE
FREEZING THIS AFTERNOON HELPING TO MELT SOME OF THE SNOW...AND CLEAR
SKIES/FRESH SNOW SHOULD ALL LEAD TO STRONG RADIATIONAL COOLING AND
ENHANCED FOG POTENTIAL. DENSE FOG WAS OBSERVED OVERNIGHT TO OUR
WEST. BUT FOR NOW...BANKING ON CLOUDY SKIES STICKING AROUND TODAY
MINIMIZING THE FOG THREAT.
LOOKING AHEAD TO THIS WEEKEND...LOOKING AT THE POTENTIAL FOR
WIDESPREAD FOG DEVELOPMENT AS STRONG MOIST ADVECTION DRIVES
DEWPOINTS INTO THE 30S AND EVENTUALLY 40S OVER DEEP SNOWPACK. THIS
TYPE OF SETUP HAS THE POTENTIAL FOR PRODUCING WIDESPREAD AND
POTENTIALLY DENSE FOG.
BMD
//ORD AND MDW CONFIDENCE...UPDATED 14Z...
* LOW CONFIDENCE ON TIMING CLEARING OF VFR CIGS...AND RESULTING
FOG POTENTIAL OVERNIGHT.
* MMEDIUM TO HIGH CONFIDENCE IN ALL OTHER FORECAST ELEMENTS.
KREIN
//OUTLOOK FOR ORD/MDW FOR 00Z SATURDAY-12Z THURSDAY...UPDATED 12Z...
FRIDAY NIGHT THROUGH SATURDAY...VFR.
SATURDAY NIGHT THROUGH SUNDAY...RAIN/FOG.
MONDAY...CHC RAIN/SNOW.
TUESDAY THROUGH WEDNESDAY...VFR.
BMD
&&
.MARINE...
311 AM CST
MAIN CONCERN THIS FORECAST PACKAGE WILL BE WINDS INCREASING BEHIND
AN AREA OF LOW PRESSURE EARLY NEXT WEEK. SHOULD BE A QUIET END OF
THE WORK WEEK WITH HIGH PRESSURE BUILDING ACROSS LAKE MICHIGAN TODAY
ALLOWING WINDS AND SUBSEQUENT WAVES TO DIMINISH. WILL ALLOW THE
SMALL CRAFT ADVISORY TO EXPIRE WITH THE MORNING NSH ISSUANCE.
SOUTHERLY WINDS FRESHEN SOME OVER THE WEEKEND AS LOW PRESSURE TAKES
SHAPE OVER THE PLAINS...BUT MAIN CONCERN WILL BE BEHIND THE LOW AS
EARLY AS SUNDAY NIGHT WHEN NORTHERLY WINDS ARE EXPECTED TO RAMP UP
TO AROUND 30 KT. THESE WINDS SHOULD CONTINUE THROUGH THE DAY MONDAY.
MODELS ARE STRUGGLING WITH THE DETAILS OF THIS SYSTEM...INCLUDING
HOW STRONG AND WELL ORGANIZED IT WILL BECOME...BUT GENERALLY
SUGGEST A BROAD TROUGH ACROSS THE AREA WITH TWO DISTINCT WAVES
DEVELOPING. DEPENDING ON HOW IT PANS OUT THERE MAY BE SLIGHTLY
STRONGER WINDS //LOW END GALES// WITH A BETTER DEVELOPED LOW OR
OVERALL WINDS MAY BE SLIGHTLY WEAKER BUT STAY ELEVATED FOR A LONGER
TIME PERIOD WITH A LESS ORGANIZED WAVE. WILL HAVE TO MAKE
ADJUSTMENTS AS MODELS LOCK ONTO A PARTICULAR SOLUTION IN THE COMING
DAYS. EITHER WAY...WINDS SHOULD BEGIN TO TAPER AGAIN MIDWEEK AS
ANOTHER RIDGE BEGINS TO BUILD INTO THE WESTERN GREAT LAKES REGION.
BMD
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
529 AM CST THU MAR 7 2013
.DISCUSSION...
330 AM CST
FORECAST CHALLENGES THIS MORNING INCLUDE CLOUDINESS THROUGH
TONIGHT...THEN THE BIG SLOPPY RAINY WET MELT DOWN EXPECTED THIS
WEEKEND.
STUBBORN STRATUS HAS NOT BUDGED AT ALL OVERNIGHT AND IS CURRENTLY
BLANKETING THE ENTIRE CWA. MODEL GUIDANCE IS NOT DOING A GREAT
JOB HANDLING CURRENT CONDITIONS WITH REGARDS TO THIS STRATUS DECK
WHICH LENDS ITSELF TO A LOWER CONFIDENCE FORECAST TODAY INTO
TONIGHT. RAP SEEMS TO HAVE THE BEST HANDLE ON LOW LEVEL RH AND IT
SUPPORTS WHAT I WAS THINKING WOULD HAPPEN CONCEPTUALLY WHICH IS
EROSION FROM THE EDGES COMMENCING AGAIN AFTER SUNRISE...ESPECIALLY
FROM THE SOUTHWEST WHERE SNOW PACK IS LESS OVER CENTRAL ILLINOIS.
RIDGE AXIS PASSING BY TODAY WILL THEN TURN LOW LEVEL EASTERLY
AND WHERE EVER THE EDGE OF THE STRATUS ENDS UP LATE THIS AFTERNOON
COULD SEE IT RE-DEVELOPING/RE-ADVECTING BACK WEST ACROSS THE CWA
TONIGHT. HUNCH IS THAT EASTERN CWA COULD STAY PRETTY SOCKED IN
TODAY WITH SOME CLEARING WEST THIS AFTERNOON BUT WITH POTENTIAL
FOR REDEVELOPMENT OF STRATUS TONIGHT. TRYING TO REFLECT THESE
TRENDS IN THE GRIDS IS GOING TO BE A CHALLENGE TO SAY THE LEAST...
TEMPS WILL BE HELD DOWN BY CLOUDS AND SNOW COVER TODAY...AND THEN
HELD UP TONIGHT WHERE STATUS ENDS UP PARKING. WESTERN CWA STANDS A
CHANCE OF SEEING CLEAR SKIES THIS EVENING AND A RAPID TEMP DROP.
GIVEN THE LIGHT WINDS THERE IS A POTENTIAL FOR SOME FREEZING
GROUND FOG DEVELOPING PRIOR TO THE ARRIVAL OF ANY STRATUS. ONCE
AGAIN TONIGHT LOW TEMPERATURE FORECAST IS VERY LOW CONFIDENCE WITH
ABOUT A 15-20F RANGE OF POSSIBLE LOWS...ESPECIALLY WESTERN CWA.
SAME DEAL FRIDAY...IF STRATUS DECK NEVER CLEARS OUT THEN CLOUDY
START WITH POSSIBLE SCATTERING OUT IN THE AFTERNOON WOULD BE
EXPECTED WITH COLDER TEMPS. CONVERSELY...SHOULD THE STRATUS BE
GONE SUNNY SKIES WITH HIGHER SUN ANGLE MARCH SUN COULD RESULT IN
FRIDAY TURNING INTO DAY 1 OF THE GREAT MELT DOWN WITH HIGHS
GETTING WELL INTO THE 30S AND MAYBE LOW 40S IN SOUTHERN CWA AND IN
MORE URBANIZED AREAS.
WEEKEND FORECAST STILL GENERALLY LOOKS ON TRACK...THOUGH MODELS HAVE
TRENDED TOWARD A SLIGHTLY WEAKER/LESS PHASED SOLUTION WOULD MEAN A
SOMEWHAT LESSER THREAT OF HEAVY RAINFALL. WE ARE STILL PRETTY FAR
OUT IN TIME AND WOULD ANTICIPATE MORE CHANGES IN FORECAST GUIDANCE
THE NEXT COUPLE DAYS...MOST LIKELY TO SLOW THE SYSTEM DOWN IF
ANYTHING...SO NOT GOING TO MAKE ANY BIG CHANGES TO GOING FORECAST
FOR THE WEEKEND. EARLY NEXT WEEK THE RUNS DE JOUR OF THE MEDIUM
RANGE GUIDANCE LOOKS LESS FOREBODING REGARDING A SNOW SYSTEM WITH A
LESS PHASED MORE POSITIVELY TILTED/PROGRESSIVE TROUGH MOVING THROUGH
BUT STILL PLENTY OF TIME FOR THAT TO CHANGE SO PROBABLY A LITTLE
PREMATURE TO PUT AWAY THE SHOVELS FOR THE YEAR YET.
IZZI
&&
.HYDROLOGY...
330 AM CST
DEEP WATER LOGGED SNOW PACK BLANKETS THE CWA WITH SNOW WATER
EQUIV`S NEAR TO OVER AN INCH OVER NORTHERN HALF OF THE CWA. RISING
TEMPS AND DEWPOINTS THIS WEEKEND SHOULD RESULT IN AN INCREASING
QUICK MELTING OF THE SNOW PACK...WITH ANY RAIN FALLING ON TOP OF
IT SERVING TO FURTHER INCREASE THE CHANCE OF SOME FLOODING
PROBLEMS DEVELOPING. CONFIDENCE IN RAINFALL TOTALS THIS WEEKEND
NOT OVERLY HIGH...BUT EARLY BALL PARK NUMBERS IN THE HALF INCH TO
ONE INCH RANGE LOOK QUITE PLAUSIBLE AND SUFFICIENT FOR SIGNIFICANT
RISES ON AREA RIVERS AND POTENTIAL FOR FLOODING. WILL CONTINUE TO
HIGHLIGHT THREAT IN THE HWO AND DAY SHIFT MAY NEED TO CONSIDER AN
ESF.
IZZI
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 12Z...
* POTENTIAL FOR MVFR CIGS THURSDAY AFTERNOON.
* POTENTIAL FOR FOG FRIDAY MORNING.
BMD
//DISCUSSION...UPDATED 12Z...
VFR STRATUS DECK REMAINS IN PLACE OVER THE CHICAGO AREA WITH HIGH
END MVFR CIGS WEST OF THE CHICAGO AREA INCLUDING RFD. GUIDANCE IS
NOT HANDLING THE SITUATION WELL NOR HOW LONG TO HANG ONTO THE CIGS
THROUGH THE DAY. HAVE TRENDED SLOWER WITH CLEARING AS COLD BOUNDARY
LAYER UNDERNEATH A MODERATE INVERSION MAY KEEP MOISTURE LOCKED IN
THROUGH THE DAY. THERE IS SUBTLE COOLING NOTED AT 925MB THIS
AFTERNOON WHICH MODEL SOUNDINGS SUGGEST MAY LEAD TO LOWERING MVFR
CIGS AROUND 020...HOWEVER THINK THE MODELS ARE LIKELY OVERDOING THE
DIURNAL HEATING COMPONENT TODAY AND RESULTANT LAPSE RATES...AND
DO NOT HAVE CONFIDENCE IN THIS SCENARIO PANNING OUT. WILL STICK WITH
SCT020 IN THE MEANTIME. WINDS ARE EXPECTED TO REMAIN LESS THAN 10 KT
THROUGH THE DAY...AND SHOULD GRADUALLY VEER FROM NW THIS MORNING TO
EASTERLY OVERNIGHT.
IN THE EVENT WE DO CLEAR OUT TODAY...WILL THEN HAVE TO KEEP AN EYE
ON THE FOG POTENTIAL. CONCEPTUALLY...LIGHT WINDS CLOSE TO THE RIDGE
AXIS...PERHAPS SOME ADDITIONAL BL MOISTURE WITH TEMPS PEAKING ABOVE
FREEZING THIS AFTERNOON HELPING TO MELT SOME OF THE SNOW...AND CLEAR
SKIES/FRESH SNOW SHOULD ALL LEAD TO STRONG RADIATIONAL COOLING AND
ENHANCED FOG POTENTIAL. DENSE FOG WAS OBSERVED OVERNIGHT TO OUR
WEST. BUT FOR NOW...BANKING ON CLOUDY SKIES STICKING AROUND TODAY
MINIMIZING THE FOG THREAT.
LOOKING AHEAD TO THIS WEEKEND...LOOKING AT THE POTENTIAL FOR
WIDESPREAD FOG DEVELOPMENT AS STRONG MOIST ADVECTION DRIVES
DEWPOINTS INTO THE 30S AND EVENTUALLY 40S OVER DEEP SNOWPACK. THIS
TYPE OF SETUP HAS THE POTENTIAL FOR PRODUCING WIDESPREAD AND
POTENTIALLY DENSE FOG.
BMD
//ORD AND MDW CONFIDENCE...UPDATED 12Z...
* LOW CONFIDENCE IN MVFR CIGS THURSDAY AFTERNOON.
* LOW CONFIDENCE ON TIMING CLEARING OF VFR CIGS...AND RESULTING
FOG POTENTIAL OVERNIGHT.
BMD
//OUTLOOK FOR ORD/MDW FOR 00Z SATURDAY-12Z THURSDAY...UPDATED 12Z...
FRIDAY NIGHT THROUGH SATURDAY...VFR.
SATURDAY NIGHT THROUGH SUNDAY...RAIN/FOG.
MONDAY...CHC RAIN/SNOW.
TUESDAY THROUGH WEDNESDAY...VFR.
BMD
&&
.MARINE...
311 AM CST
MAIN CONCERN THIS FORECAST PACKAGE WILL BE WINDS INCREASING BEHIND
AN AREA OF LOW PRESSURE EARLY NEXT WEEK. SHOULD BE A QUIET END OF
THE WORK WEEK WITH HIGH PRESSURE BUILDING ACROSS LAKE MICHIGAN TODAY
ALLOWING WINDS AND SUBSEQUENT WAVES TO DIMINISH. WILL ALLOW THE
SMALL CRAFT ADVISORY TO EXPIRE WITH THE MORNING NSH ISSUANCE.
SOUTHERLY WINDS FRESHEN SOME OVER THE WEEKEND AS LOW PRESSURE TAKES
SHAPE OVER THE PLAINS...BUT MAIN CONCERN WILL BE BEHIND THE LOW AS
EARLY AS SUNDAY NIGHT WHEN NORTHERLY WINDS ARE EXPECTED TO RAMP UP
TO AROUND 30 KT. THESE WINDS SHOULD CONTINUE THROUGH THE DAY MONDAY.
MODELS ARE STRUGGLING WITH THE DETAILS OF THIS SYSTEM...INCLUDING
HOW STRONG AND WELL ORGANIZED IT WILL BECOME...BUT GENERALLY
SUGGEST A BROAD TROUGH ACROSS THE AREA WITH TWO DISTINCT WAVES
DEVELOPING. DEPENDING ON HOW IT PANS OUT THERE MAY BE SLIGHTLY
STRONGER WINDS //LOW END GALES// WITH A BETTER DEVELOPED LOW OR
OVERALL WINDS MAY BE SLIGHTLY WEAKER BUT STAY ELEVATED FOR A LONGER
TIME PERIOD WITH A LESS ORGANIZED WAVE. WILL HAVE TO MAKE
ADJUSTMENTS AS MODELS LOCK ONTO A PARTICULAR SOLUTION IN THE COMING
DAYS. EITHER WAY...WINDS SHOULD BEGIN TO TAPER AGAIN MIDWEEK AS
ANOTHER RIDGE BEGINS TO BUILD INTO THE WESTERN GREAT LAKES REGION.
BMD
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
330 AM CST THU MAR 7 2013
.DISCUSSION...
330 AM CST
FORECAST CHALLENGES THIS MORNING INCLUDE CLOUDINESS THROUGH
TONIGHT...THEN THE BIG SLOPPY RAINY WET MELT DOWN EXPECTED THIS
WEEKEND.
STUBBORN STRATUS HAS NOT BUDGED AT ALL OVERNIGHT AND IS CURRENTLY
BLANKETING THE ENTIRE CWA. MODEL GUIDANCE IS NOT DOING A GREAT
JOB HANDLING CURRENT CONDITIONS WITH REGARDS TO THIS STRATUS DECK
WHICH LENDS ITSELF TO A LOWER CONFIDENCE FORECAST TODAY INTO
TONIGHT. RAP SEEMS TO HAVE THE BEST HANDLE ON LOW LEVEL RH AND IT
SUPPORTS WHAT I WAS THINKING WOULD HAPPEN CONCEPTUALLY WHICH IS
EROSION FROM THE EDGES COMMENCING AGAIN AFTER SUNRISE...ESPECIALLY
FROM THE SOUTHWEST WHERE SNOW PACK IS LESS OVER CENTRAL ILLINOIS.
RIDGE AXIS PASSING BY TODAY WILL THEN TURN LOW LEVEL EASTERLY
AND WHERE EVER THE EDGE OF THE STRATUS ENDS UP LATE THIS AFTERNOON
COULD SEE IT RE-DEVELOPING/RE-ADVECTING BACK WEST ACROSS THE CWA
TONIGHT. HUNCH IS THAT EASTERN CWA COULD STAY PRETTY SOCKED IN
TODAY WITH SOME CLEARING WEST THIS AFTERNOON BUT WITH POTENTIAL
FOR REDEVELOPMENT OF STRATUS TONIGHT. TRYING TO REFLECT THESE
TRENDS IN THE GRIDS IS GOING TO BE A CHALLENGE TO SAY THE LEAST...
TEMPS WILL BE HELD DOWN BY CLOUDS AND SNOW COVER TODAY...AND THEN
HELD UP TONIGHT WHERE STATUS ENDS UP PARKING. WESTERN CWA STANDS A
CHANCE OF SEEING CLEAR SKIES THIS EVENING AND A RAPID TEMP DROP.
GIVEN THE LIGHT WINDS THERE IS A POTENTIAL FOR SOME FREEZING
GROUND FOG DEVELOPING PRIOR TO THE ARRIVAL OF ANY STRATUS. ONCE
AGAIN TONIGHT LOW TEMPERATURE FORECAST IS VERY LOW CONFIDENCE WITH
ABOUT A 15-20F RANGE OF POSSIBLE LOWS...ESPECIALLY WESTERN CWA.
SAME DEAL FRIDAY...IF STRATUS DECK NEVER CLEARS OUT THEN CLOUDY
START WITH POSSIBLE SCATTERING OUT IN THE AFTERNOON WOULD BE
EXPECTED WITH COLDER TEMPS. CONVERSELY...SHOULD THE STRATUS BE
GONE SUNNY SKIES WITH HIGHER SUN ANGLE MARCH SUN COULD RESULT IN
FRIDAY TURNING INTO DAY 1 OF THE GREAT MELT DOWN WITH HIGHS
GETTING WELL INTO THE 30S AND MAYBE LOW 40S IN SOUTHERN CWA AND IN
MORE URBANIZED AREAS.
WEEKEND FORECAST STILL GENERALLY LOOKS ON TRACK...THOUGH MODELS HAVE
TRENDED TOWARD A SLIGHTLY WEAKER/LESS PHASED SOLUTION WOULD MEAN A
SOMEWHAT LESSER THREAT OF HEAVY RAINFALL. WE ARE STILL PRETTY FAR
OUT IN TIME AND WOULD ANTICIPATE MORE CHANGES IN FORECAST GUIDANCE
THE NEXT COUPLE DAYS...MOST LIKELY TO SLOW THE SYSTEM DOWN IF
ANYTHING...SO NOT GOING TO MAKE ANY BIG CHANGES TO GOING FORECAST
FOR THE WEEKEND. EARLY NEXT WEEK THE RUNS DE JOUR OF THE MEDIUM
RANGE GUIDANCE LOOKS LESS FOREBODING REGARDING A SNOW SYSTEM WITH A
LESS PHASED MORE POSITIVELY TILTED/PROGRESSIVE TROUGH MOVING THROUGH
BUT STILL PLENTY OF TIME FOR THAT TO CHANGE SO PROBABLY A LITTLE
PREMATURE TO PUT AWAY THE SHOVELS FOR THE YEAR YET.
IZZI
&&
.HYDROLOGY...
330 AM CST
DEEP WATER LOGGED SNOW PACK BLANKETS THE CWA WITH SNOW WATER
EQUIV`S NEAR TO OVER AN INCH OVER NORTHERN HALF OF THE CWA. RISING
TEMPS AND DEWPOINTS THIS WEEKEND SHOULD RESULT IN AN INCREASING
QUICK MELTING OF THE SNOW PACK...WITH ANY RAIN FALLING ON TOP OF
IT SERVING TO FURTHER INCREASE THE CHANCE OF SOME FLOODING
PROBLEMS DEVELOPING. CONFIDENCE IN RAINFALL TOTALS THIS WEEKEND
NOT OVERLY HIGH...BUT EARLY BALL PARK NUMBERS IN THE HALF INCH TO
ONE INCH RANGE LOOK QUITE PLAUSIBLE AND SUFFICIENT FOR SIGNIFICANT
RISES ON AREA RIVERS AND POTENTIAL FOR FLOODING. WILL CONTINUE TO
HIGHLIGHT THREAT IN THE HWO AND DAY SHIFT MAY NEED TO CONSIDER AN
ESF.
IZZI
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 09Z...
* POTENTIAL FOR MVFR CIGS THURSDAY AFTERNOON.
BMD
//DISCUSSION...UPDATED 06Z...
SHOULD BE A FAIRLY QUIET TAF PERIOD AS HIGH PRESSURE BUILDS ACROSS
THE AREA. RIDGE AXIS IS CENTERED ALONG THE MISSISSIPPI VALLEY LATE
THIS EVENING AND WILL SLOWLY SLIDE EAST THROUGH THE PERIOD. VFR
STRATUS DECK REMAINS IN PLACE ACROSS MOST OF NORTHERN ILLINOIS AND
SUSPECT WE WILL REMAIN LOCKED IN AS THERE IS NO SIGN OF THE BACK
EDGE ERODING SINCE SUNSET. GIVEN THE LATEST THOUGHTS ON STRATUS
REMAINING...REMOVED MENTION OF FOG FOR RFD. WILL HAVE TO MONITOR
THIS CLOSELY THOUGH AS DENSE FOG IS ALREADY FORMING WHERE SKIES HAVE
CLEARED OVER EASTERN IOWA. EXPECT THE STRATUS TO BEGIN ERODING FROM
THE WEST IN EARNEST AFTER DAYBREAK THURSDAY. ONCE WE GET UNDER MARCH
SUNSHINE...EXPECT SURFACE TEMPS TO WARM TO AROUND THE FREEZING MARK
WITH STEEP LOW LEVEL LAPSE RATES DEVELOPING. MODEL SOUNDINGS SHOW
POTENTIAL TO DEVELOP SOME MVFR CU/CASCU TUESDAY AFTERNOON...BUT
SIGNAL IS MIXED SO FOR NOW JUST INTRODUCED A SCT020 DECK. WINDS
SHOULD REMAIN RELATIVELY LIGHT...LESS THAN 10 KT THROUGH THE
PERIOD...TRENDING TO THE EAST THURSDAY EVENING BEHIND THE RIDGE
AXIS. BMD
//ORD AND MDW CONFIDENCE...UPDATED 09Z...
* LOW CONFIDENCE IN MVFR CIGS THURSDAY AFTERNOON.
* HIGH CONFIDENCE IN ALL OTHER FORECAST ELEMENTS.
BMD
//OUTLOOK FOR ORD/MDW FOR 12Z FRIDAY-12Z THURSDAY...UPDATED 00Z...
THURSDAY NIGHT THROUGH FRIDAY...VFR.
SATURDAY THROUGH SUNDAY...CHC RAIN.
SUNDAY...RAIN...MVFR.
SUNDAY NIGHT...RAIN AND SNOW...IFR LIKELY.
MONDAY...RAIN...MVFR LIKELY.
TUESDAY...VFR.
DZ
&&
.MARINE...
311 AM CST
MAIN CONCERN THIS FORECAST PACKAGE WILL BE WINDS INCREASING BEHIND
AN AREA OF LOW PRESSURE EARLY NEXT WEEK. SHOULD BE A QUIET END OF
THE WORK WEEK WITH HIGH PRESSURE BUILDING ACROSS LAKE MICHIGAN TODAY
ALLOWING WINDS AND SUBSEQUENT WAVES TO DIMINISH. WILL ALLOW THE
SMALL CRAFT ADVISORY TO EXPIRE WITH THE MORNING NSH ISSUANCE.
SOUTHERLY WINDS FRESHEN SOME OVER THE WEEKEND AS LOW PRESSURE TAKES
SHAPE OVER THE PLAINS...BUT MAIN CONCERN WILL BE BEHIND THE LOW AS
EARLY AS SUNDAY NIGHT WHEN NORTHERLY WINDS ARE EXPECTED TO RAMP UP
TO AROUND 30 KT. THESE WINDS SHOULD CONTINUE THROUGH THE DAY MONDAY.
MODELS ARE STRUGGLING WITH THE DETAILS OF THIS SYSTEM...INCLUDING
HOW STRONG AND WELL ORGANIZED IT WILL BECOME...BUT GENERALLY
SUGGEST A BROAD TROUGH ACROSS THE AREA WITH TWO DISTINCT WAVES
DEVELOPING. DEPENDING ON HOW IT PANS OUT THERE MAY BE SLIGHTLY
STRONGER WINDS //LOW END GALES// WITH A BETTER DEVELOPED LOW OR
OVERALL WINDS MAY BE SLIGHTLY WEAKER BUT STAY ELEVATED FOR A LONGER
TIME PERIOD WITH A LESS ORGANIZED WAVE. WILL HAVE TO MAKE
ADJUSTMENTS AS MODELS LOCK ONTO A PARTICULAR SOLUTION IN THE COMING
DAYS. EITHER WAY...WINDS SHOULD BEGIN TO TAPER AGAIN MIDWEEK AS
ANOTHER RIDGE BEGINS TO BUILD INTO THE WESTERN GREAT LAKES REGION.
BMD
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS LINCOLN IL
307 AM CST THU MAR 7 2013
.DISCUSSION...
ISSUED 307 AM CST THU MAR 7 2013
EARLY MORNING SURFACE MAP SHOWED HIGH PRESSURE RIDGING RUNNING THE
LENGTH OF THE MISSISSIPPI RIVER. RATHER TIGHT INVERSION JUST ABOVE
900 MB HAS PUT THE KIBOSH ON ANY REAL EROSION OF THE LARGE
STRATOCUMULUS DECK OVER MUCH OF THE MIDWEST...WITH ONLY AREAS
AROUND JACKSONVILLE SEEING ANY SUSTAINED CLEARING AND THAT HAS
BEGUN TO FILL IN AS WELL. THE CLOUDS HAVE KEPT TEMPERATURES IN THE
20S...WHICH IS GOOD SINCE CLEAR SKIES OVER THE SUBSTANTIAL SNOW
COVER IN THE NORTHERN CWA WOULD HAVE LIKELY RESULTED IN SINGLE
DIGITS AND TEENS IN THAT AREA. LOOKING UPSTAIRS...LATEST WATER
VAPOR IMAGERY SHOWING SEVERAL CIRCULATIONS IN A BROAD AREA OF 500
MB LOW PRESSURE OVER THE PACIFIC NORTHWEST. DEVELOPMENT OF THIS
PARTICULAR FEATURE WILL BE OF INTEREST TO OUR FORECAST FOR THE
WEEKEND.
SHORT TERM...TODAY THROUGH FRIDAY...
FAIRLY QUIET WEATHER EXPECTED IN THE SHORT TERM...AS THE HIGH
PUSHES EAST ACROSS THE GREAT LAKES. FORECAST SOUNDINGS SHOW THE
INVERSION SLOW TO ERODE THOUGH...SO WILL KEEP THE EASTERN CWA
FAIRLY CLOUDY TODAY AND TRY TO MARK SOME CLEARING ACROSS THE WEST
BY MIDDAY. MAIN CONCERN WILL BE WITH FOG POTENTIAL TONIGHT ACROSS
THE NORTH...WITH WINDS STILL FAIRLY LIGHT AND SOME POTENTIAL FOR
SNOW MELT TODAY. SHOULD SKIES STAY CLOUDY...THIS WOULD BE LESS OF
A CONCERN.
TEMPERATURE-WISE...WILL CONTINUE THE TREND OF KEEPING HIGHS A FEW
DEGREES COOLER ACROSS THE NORTH WHERE THE SNOW DEPTH RANGES FROM 5
TO 9 INCHES. HOWEVER...EVEN THESE AREAS MAY CRACK 40 BY FRIDAY...
WITH HIGHS 45-50 FURTHER SOUTH.
LONG TERM...SATURDAY THROUGH WEDNESDAY...
UPPER LOW IN THE PACIFIC NORTHWEST SHOULD BETTER ORGANIZE AS IT
DROPS SOUTHWARD ALONG THE CALIFORNIA COAST TONIGHT AND FRIDAY.
LATEST MODEL GUIDANCE CONTINUES TO EJECT THIS FEATURE NORTHEAST
THIS WEEKEND...AS A DEEPENING SHORTWAVE TRACKS EAST ACROSS THE
CANADIAN PRAIRIES. SOME PHASING OF THE TWO FEATURES IS INDICATED
LATER THIS WEEKEND OVER THE CENTRAL U.S. AND THIS WILL
SIGNIFICANTLY INCREASE PRECIP CHANCES AS THE WEEKEND PROGRESSES.
GOOD MOISTURE SURGE SHOULD TAKE PLACE AHEAD OF THIS PHASING...
WITH GFS PRECIPITABLE WATER VALUES OF 1.25 INCHES SATURDAY NIGHT
NEAR THE 99TH PERCENTILE FOR EARLY MARCH. WOULD NOT BE SURPRISED
TO SEE OVER AN INCH OF RAIN IN SOME AREAS SATURDAY NIGHT THROUGH
SUNDAY NIGHT. HAVE INTRODUCED CATEGORICAL RAIN CHANCES SATURDAY
NIGHT NORTHWEST OF THE ILLINOIS RIVER...AND ALSO ADDED AREAS OF
FOG ACROSS THE NORTHERN CWA DUE TO THE HEAVIER RAIN AND RAPID SNOW
MELT. SUNDAY WILL START OUT RATHER WET AS WELL. HOWEVER...THE
MODELS BEGIN TO DIVERGE IN TERMS OF WHETHER A DRY SLOT MAY SPREAD
IN DURING THE DAY. WITH THE DIVERSITY...WILL NOT TRY TO GET TOO
CUTE WITH SPLITTING OUT MORNING AND AFTERNOON PERIODS.
TEMPERATURES BOTH DAYS SHOULD REACH WELL INTO THE 50S.
SUNDAY NIGHT AND MONDAY...THE GFS AND ECMWF MODELS BOTH SHOW THE
NORTHERN WAVE EXITING THE AREA...WHILE ANOTHER LOW DEVELOPS OVER
THE SOUTHERN PLAINS. THE GFS IS MORE AGGRESSIVE WITH CLOSING THIS
LOW OFF AND LIFTING IT NORTHEAST...WHILE THE ECMWF WEAKENS BACK
INTO AN OPEN WAVE. LEANING MORE TOWARD THE ECMWF SOLUTION FOR
NOW...AND HAVE LIMITED LIKELY POPS SUNDAY NIGHT TO THE SOUTHEAST
THIRD OF THE CWA. HAVE KEPT SOME PRECIP CHANCES IN ON MONDAY FOR
NOW...BUT CONFIDENCE IS LOW AT THE MOMENT. HAVE LARGELY KEPT THE
PRECIP AS RAIN EXCEPT FOR A MIX IN THE NORTHWEST.
MODEL AGREEMENT DOES NOT IMPROVE AS THE WEEK PROGRESSES...WITH THE
LONGER RANGE SOLUTIONS VARYING WITH THE STRENGTH OF ANOTHER WAVE
DROPPING INTO THE GREAT LAKES ON TUESDAY. THE ECMWF SOLUTION WOULD
BE MUCH COOLER FOR US WITH SIGNIFICANT RIDGING WEST OF THE
ROCKIES. FOR NOW HAVE KEPT TEMPERATURES ABOUT 5 DEGREES BELOW
NORMAL FOR THE END OF THE FORECAST PERIOD.
GEELHART
&&
.AVIATION...
ISSUED 1150 PM CST WED MAR 6 2013
BROKEN TO OVERCAST MVFR CEILINGS OF 1.5-2.5K FT TO PREVAIL DURING
OVERNIGHT ACROSS THE CENTRAL IL TERMINAL AIRPORTS...AS STRONG
INVERSION FROM 900-750 MB TRAPS LOW LEVEL MOISTURE/CLOUDS (1-2K FT
THICK) WITH WEAK NNW FLOW. USED RAP MODEL 925-850 MB RH FIELD FOR
SCATTERING OUT THIS LOW CLOUD DECK FIRST AT SPI AND PIA BETWEEN
11-13Z AND LAST AT CMI AFTER 16Z THU. COULD BE VSBYS OF 4-6 MILES AS
CLOUDS SCATTER OUT THU MORNING. ALSO HAVE REPORTS OF FLURRIES PAST
FEW HOURS AT CMI AND COULD BE A CHANCE OF FLURRIES OVERNIGHT
MAINLY ALONG I-74 TAF SITES. NW WINDS OF 5-10 KTS TO DIMINISH
LIGHT DURING OVERNIGHT AND VEER NORTHERLY. LIGHT AND VARIABLE WINDS
EXPECTED THU AS 1030 MB HIGH PRESSURE RIDGE FROM EASTERN MN/IA AND
INTO MO DRIFTS EAST ACROSS IL BY 18Z/NOON THU.
07
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS LINCOLN IL
1152 PM CST WED MAR 6 2013
.DISCUSSION...
ISSUED 900 PM CST WED MAR 6 2013
UPDATED THE FORECAST TO KEEP LOW CLOUDS IN THE FORECAST LONGER
TONIGHT AND ALSO NUDGE LOW TEMPERATURES UP A BIT DUE TO LINGERING
LOW CLOUDS. MOSTLY CLOUDY TO OVERCAST SKIES TONIGHT EXCEPT LESS
CLOUD COVER OVER 4 SW COUNTIES OF SCHUYLER...SCOTT...CASS AND
MORGAIN FROM JACKSONVILLE SW. LOWS IN THE LOW TO MID 20S EXPECT
SOME UPPER TEENS FROM GALESBURG TO JACKSONVILLE WEST. NW WINDS
5-10 MPH TURNING LIGHT NNW LATER TONIGHT.
OVERCAST LOW CLOUDS FROM 1.5-3K FT BLANKET MUCH OF CENTRAL AND NE
IL INTO SE IA/WI AT MID EVENING WITH CLEARING SW OF JACKSONVILLE.
CLOUD LAYER IS ABOUT 1-2 K FT THICK PER KILX/KDVN SOUNDINGS AND
PILOT REPORTS THIS EVENING. 00Z KILX SOUNDING SHOWS STRONG
INVERSION FROM JUST ABOVE 900 MB TO 750 MB SO THIS IS TRAPPING LOW
LEVEL MOISTURE/CLOUDS OVER CENTRAL/SE IL TONIGHT WITH LIGHTER
FLOW. RAP MODEL 925-850 MB RH CAPTURING THIS CLOUD FIELD WELL
WHICH KEEPS ABUNDANT LOW CLOUDS OVER CENTRAL AND SE THROUGH THE
NIGHT WITH SOME DECREASING OF LOW CLOUDS FROM PEORIA TO
TAYLORVILLE LATER TONIGHT AND INTO EASTERN IL DURING THU MORNING
AS 1030 MB HIGH PRESSURE RIDGE OVER MN INTO CENTRAL IA/MO DRIFTS
EAST ACROSS THE MS VALLEY INTO IL THU. A LIGHT FOG COULD DEVELOP
OVER WEST CENTRAL AND NW IL LATER TONIGHT WHERE LESS LOW CLOUDS AND
LIGHTER NNW WINDS PREVAIL.
07
&&
.AVIATION...
ISSUED 1150 PM CST WED MAR 6 2013
BROKEN TO OVERCAST MVFR CEILINGS OF 1.5-2.5K FT TO PREVAIL DURING
OVERNIGHT ACROSS THE CENTRAL IL TERMINAL AIRPORTS...AS STRONG
INVERSION FROM 900-750 MB TRAPS LOW LEVEL MOISTURE/CLOUDS (1-2K FT
THICK) WITH WEAK NNW FLOW. USED RAP MODEL 925-850 MB RH FIELD FOR
SCATTERING OUT THIS LOW CLOUD DECK FIRST AT SPI AND PIA BETWEEN
11-13Z AND LAST AT CMI AFTER 16Z THU. COULD BE VSBYS OF 4-6 MILES AS
CLOUDS SCATTER OUT THU MORNING. ALSO HAVE REPORTS OF FLURRIES PAST
FEW HOURS AT CMI AND COULD BE A CHANCE OF FLURRIES OVERNIGHT
MAINLY ALONG I-74 TAF SITES. NW WINDS OF 5-10 KTS TO DIMINISH
LIGHT DURING OVERNIGHT AND VEER NORTHERLY. LIGHT AND VARIABLE WINDS
EXPECTED THU AS 1030 MB HIGH PRESSURE RIDGE FROM EASTERN MN/IA AND
INTO MO DRIFTS EAST ACROSS IL BY 18Z/NOON THU.
07
&&
.PREV DISCUSSION...
ISSUED 231 PM CST WED MAR 6 2013
MODELS IN REASONABLE AGREEMENT OVER THE 7-DAY PERIOD...PARTICULARLY
GIVEN THE PRIMARY ENERGY TO IMPACT ILLINOIS THIS WEEKEND IS
RELATIVELY POORLY SAMPLED OFF THE PACIFIC COAST.
SHORT TERM...TONIGHT THROUGH SATURDAY
STORM SYSTEM THAT BROUGHT SNOW TO FORECAST AREA YESTERDAY IS NOW
ALONG THE MID-ATLANTIC COAST AND CONTINUES TO DIMINISH ITS IMPACT ON
ILLINOIS AS HIGH PRESSURE OVER MID-MISSOURI VALLEY PUSHES EASTWARD.
PLENTIFUL CLOUDINESS PERSISTS TO THE EAST OF THE RIDGE AXIS AND
WILL ONLY GRADUALLY DIMINISH AS THE RIDGE PUSHES EAST TONIGHT.
WILL HAVE TO MONITOR CLOSELY AS DEVELOPING BREAKS MAY LEAD TO
LOWER TEMPS THAN FORECAST IN SNOW COVERED AREAS AS WELL AS A
POTENTIAL FOR FOG...PARTICULARLY WESTERN COUNTIES.
THERE HAS BEEN SOME SNOW MELT/COMPACTION TODAY IN OCCASIONAL SUNSHINE
DESPITE THE COLD TEMPERATURES. HAVE TEMPERED TOMORROWS HIGH
FORECAST A TAD GIVEN THE IMPACT OF THE REMAINING SNOW...BUT WITH
MARCH SUN AND RAPIDLY RISING 850 TEMPS...FEEL SNOW MAY ONLY HAVE A
MINOR IMPACT ON FRIDAYS TEMPS AND SHOULD BE GONE BY SATURDAY. WITH
LIGHT WINDS IN PLACE WITH DEEP RIDGING WILL HAVE TO MONITOR
CONDITIONS FOR POTENTIAL OF FOG BOTH THURSDAY AND FRIDAY NIGHTS.
BY SATURDAY AFTERNOON SOUTHEAST WINDS AND 850 TEMPERATURES
INCREASING TO AROUND 10C SHOULD SUPPORT HIGHS REACHING INTO THE
50S.
LONG TERM...SATURDAY NIGHT THROUGH WEDNESDAY
STRONG SYSTEM CURRENTLY OFF THE NW PACIFIC COAST IS PROGGED TO PLUNGE
INTO THE SW U.S. AND THEN APPROACH ILLINOIS BY SATURDAY NIGHT.
WITH THIS SHIFT TO MORE OF PACIFIC STORM TRACK...PRECIP WITH THIS
NEXT SYSTEM SHOULD BE MOSTLY RAIN. ENERGY IS EXPECTED TO BE
EJECTED TOWARD US IN A PIECEMEAL FASHION PROVIDING US WITH SEVERAL
WAVES OF PRECIP INTO MONDAY. RAINFALL AMOUNTS MAY BE
SIGNIFICANT...PARTICULARLY IN OUR NORTHERN COUNTIES WHERE SNOWMELT
RUNOFF WILL CONTRIBUTE. PRECIP WATER FORECASTS FROM THE GFS HAVE
VALUES AS HIGH AS 1.15 INCHES LATE SATURDAY NIGHT WHICH IS 2+ SD
ABOVE NORMAL FOR MARCH. TOTAL 48-HOUR AMOUNTS MAY LOCALLY APROACH
2 INCHES.
SOME COLDER AIR FILTERS IN BEHIND THE LOW ON MONDAY...BUT BOUNDARY
LAYER TEMPS AT THIS POINT SUGGEST THAT THE PRECIP MAY ONLY
BRIEFLY MIX WITH OR CHANGE TO SNOW BEFORE ENDING.
IN WAKE OF SYSTEM...TEMPS SHOULD BE 5-10 DEGREES BELOW NORMAL
THROUGH WEDNESDAY. COLDER TEMPS SHOULD REMAIN NORTH OF THE AREA
WITH HIGH ZONAL COMPONENT UPPER LEVEL FLOW.
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS QUAD CITIES IA IL
1122 AM CST THU MAR 7 2013
.UPDATE...
THE STRONGER MARCH SUN HAS STARTED TO ERODE THE LOW CLOUDS OVER
THE SOUTHWEST PART OF THE CWFA WITH SOME ADDITIONAL INROADS ACROSS
THE FAR SOUTH. IF CURRENT SATELLITE TRENDS HOLD...THE NORTHWEST
MOVEMENT OF THE CLOUDS APPEARS TO HAVE REACHED ITS MAXIMUM AND
THERE SHOULD BE A SLOW EROSION AROUND THE EDGES DURING THE
AFTERNOON. ..08..
&&
.AVIATION...
CURRENT 1-2KFT AGL CLOUDS ARE NOT BEING HANDLED WELL BY ANY MODEL.
WEAK SOUTHEAST FLOW IN THE LOW LEVELS HAS ADVECTED THE CLOUDS
NORTHWEST BUT THE STRONGER MARCH SUN MAY HAVE STOPPED THE
NORTHWEST MOVEMENT. MVFR CONDITIONS WILL BE SEEN AT KDBQ/KMLI/KBRL
WITH AN EVENTUAL IMPROVEMENT TO VFR EITHER PRIOR TO 00Z/08 OR BY
12Z/08. KCID SHOULD REMAIN VFR BUT MAY HAVE BRIEF INCURSIONS OF
MVFR THROUGH 21Z/07. ..08..
&&
.PREV DISCUSSION... /ISSUED 1012 AM CST THU MAR 7 2013/
UPDATE...
BASED ON DATA THROUGH MID MORNING WILL BE DOING A SIGNIFICANT
REVISION TO THE FCST FOR CLOUDS.
12Z UA DATA HAS A VERY THIN LAYER OF MOISTURE IN THE SOUNDINGS
TRAPPED BELOW THE INVERSION. THIS LAYER IS ON THE ORDER OF 200-300
FT THICK AND IS ROUGHLY 0.75 TO 0.90 KM ABOVE THE GROUND. THE RAP
MODEL AT LEAST HAS CLOUDS BUT THEY ARE TOO LOW IN THE FCST
SOUNDINGS.
THE RAP TRENDS AT THE 0.5 AND 1 KM LEVELS SHOW VERY WEAK SOUTHEAST
TO SOUTH SOUTHEAST FLOW WITH A SLOW UPGLIDE ON THE CONDENSATION
PRESSURE LEVELS. ADD TO THIS WAA OCCURRING ALOFT AND THE INVERSION
SHOULD ONLY STRENGTHEN DURING THE DAY. THE STRONGER MARCH SUN
SHOULD ALLOW SOME BREAKS TO DEVELOP IN THE CLOUDS BUT THE OVERALL
SIGNAL SUGGESTS THAT CLOUDS WILL REMAIN ACROSS THE AREA.
RECENT SATELLITE TRENDS ARE SHOWING A SLOW DRIFT TO THE NORTHWEST
WITH THE LOW CLOUDS AS HIGHER CLOUDS MOVE IN FROM THE WEST. THIS
TREND WITH THE LOW CLOUDS WILL LIKELY CONTINUE FOR SEVERAL MORE
HOURS AND MAY EVENTUALLY STOP. ANY CLEARING THAT OCCURS TODAY WILL
BE FROM THE SOUTH AND WILL BE VERY SLOW.
THE CLOUD COVER WILL THEN HAVE AN IMPACT ON TEMPERATURES WITH A
POTENTIAL SLIGHT LOWERING OF HIGHS FOR AREAS UNDER THE CLOUDS.
IF THE RAP TRENDS ARE CORRECT...THE CLOUDS MAY PERSIST INTO
TONIGHT. ..08..
&&
.DVN WATCHES/WARNINGS/ADVISORIES...
IA...NONE.
IL...NONE.
MO...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS QUAD CITIES IA IL
1012 AM CST THU MAR 7 2013
.UPDATE...
BASED ON DATA THROUGH MID MORNING WILL BE DOING A SIGNIFICANT
REVISION TO THE FCST FOR CLOUDS.
12Z UA DATA HAS A VERY THIN LAYER OF MOISTURE IN THE SOUNDINGS
TRAPPED BELOW THE INVERSION. THIS LAYER IS ON THE ORDER OF 200-300
FT THICK AND IS ROUGHLY 0.75 TO 0.90 KM ABOVE THE GROUND. THE RAP
MODEL AT LEAST HAS CLOUDS BUT THEY ARE TOO LOW IN THE FCST
SOUNDINGS.
THE RAP TRENDS AT THE 0.5 AND 1 KM LEVELS SHOW VERY WEAK SOUTHEAST
TO SOUTH SOUTHEAST FLOW WITH A SLOW UPGLIDE ON THE CONDENSATION
PRESSURE LEVELS. ADD TO THIS WAA OCCURRING ALOFT AND THE INVERSION
SHOULD ONLY STRENGTHEN DURING THE DAY. THE STRONGER MARCH SUN
SHOULD ALLOW SOME BREAKS TO DEVELOP IN THE CLOUDS BUT THE OVERALL
SIGNAL SUGGESTS THAT CLOUDS WILL REMAIN ACROSS THE AREA.
RECENT SATELLITE TRENDS ARE SHOWING A SLOW DRIFT TO THE NORTHWEST
WITH THE LOW CLOUDS AS HIGHER CLOUDS MOVE IN FROM THE WEST. THIS
TREND WITH THE LOW CLOUDS WILL LIKELY CONTINUE FOR SEVERAL MORE
HOURS AND MAY EVENTUALLY STOP. ANY CLEARING THAT OCCURS TODAY WILL
BE FROM THE SOUTH AND WILL BE VERY SLOW.
THE CLOUD COVER WILL THEN HAVE AN IMPACT ON TEMPERATURES WITH A
POTENTIAL SLIGHT LOWERING OF HIGHS FOR AREAS UNDER THE CLOUDS.
IF THE RAP TRENDS ARE CORRECT...THE CLOUDS MAY PERSIST INTO
TONIGHT. ..08..
&&
.PREV DISCUSSION... /ISSUED 547 AM CST THU MAR 7 2013/
SYNOPSIS...
ISSUED AT 341 AM CST THU MAR 7 2013
ANOTHER RELATIVELY QUIET MORNING ACROSS THE AREA WITH THE STRONG
SURFACE RIDGE OVER THE FORECAST AREA. STRATUS LINGERS OVER THE
FORECAST AREA NEAR AND EAST OF THE SURFACE RIDGE. WHERE THE
STRATUS HAS CLEARED OUT...PATCHY TO AREAS OF FOG HAVE
DEVELOPED...MAINLY OVER THE NORTHERN PORTIONS OF EASTERN IOWA
WHERE THE STRATUS CLEARED EARLY IN THE EVENING. CLOSER TO THE
WESTERN EDGE OF THE STRATUS THE FOG IS LESS. THE FOG HAS NOT BEEN
CONSISTENT IN AREAL COVERAGE...WITH SITES VARYING WIDELY IN
VISIBILITY OVER THE LAST FEW HOURS. ALOFT...WE HAVE RIDGING AT
NEARLY ALL LEVELS OVER THE MIDWEST WITH VERY DRY 850MB AIR OVER
THE AREA. THE STORM THAT BROUGHT SNOW TO THE AREA TUESDAY IS NOW
JUST OFF THE EAST COAST. ..LE..
SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 341 AM CST THU MAR 7 2013
DECEPTIVELY QUIET FORECAST WITH THE MAIN CONCERNS OVER THE FOG EARLY
THIS MORNING...THE EXPECTED GRADUAL DIMINISHING OF THE
STRATUS...AND TEMPERATURES TODAY AND TONIGHT.
THIS MORNINGS FOG IS A CLASSIC RADIATIONAL FOG EVENT WITH THE
SURFACE RIDGE OVERHEAD...LIGHT WINDS AND SMALL DEWPOINT DEPRESSIONS.
HOWEVER...FOG IS VERY PATCHY IN NATURE AND VISIBILITIES HAVE BEEN
RANGING FROM A FEW QUARTER MILE REPORTS TO P6SM. HOWEVER...WITH
DAWN APPROACHING AND TEMPERATURES GETTING CONSISTENTLY CLOSER TO
MINS...WE MAY HAVE A MORE CONSISTENT COVERAGE OF THE FOG HERE IN THE
NEXT FEW HOURS. FOR NOW...HAVE HELD OFF ON DOING A DENSE FOG
ADVISORY BUT WILL KEEP A CLOSE EYE ON CONDITIONS AND REEVALUATE AT
NEED.
THE STRATUS SHOULD FINALLY MOVE OFF TO THE EAST TODAY WITH WARM AIR
ADVECTION MOVING IN ALOFT...WARMER TEMPERATURES AND SOME MIXING OF
THE COLUMN TO HELP DISSIPATE THE STRATUS FROM WEST TO EAST.
ALSO...AS THE LOW LEVEL RIDGE SHIFTS EAST AND THIS SHOULD HELP TO
BODILY SHIFT THE STRATUS EAST...DESPITE THE WINDS BENEATH THE
INVERSION GOING FROM NEARLY CALM TO LIGHT SOUTHEAST...WHICH WOULD
BRING THE STRATUS BACK INTO THE AREA. THUS...HAVE GRADUALLY CLEARED
CLOUDS DURING THE MORNING HOURS AND WE SHOULD HAVE A SUNNY OR MOSTLY
SUNNY AFTERNOON. MIXING OF THE LOWEST LAYERS AND WARM AIR ADVECTION
SETTING IN ALOFT IN COMBINATION WITH SOME MORE SUNSHINE SHOULD HELP
BOOST TEMPERATURES TODAY. HAVE PUT HIGH TEMPERATURES IN THE 30S
NEARLY EVERYWHERE...BUT WOULD NOT BE SURPRISED TO SEE TEMPS IN THE
SOUTHWEST APPROACH 40 THIS AFTERNOON AS LONG AS THE STRATUS CLEARS
FAIRLY EARLY THIS MORNING. TONIGHT...WARM AIR ADVECTION GOING ON
ALOFT...LIGHT SOUTHEAST WINDS AND INCREASING HIGHER CLOUDS SHOULD
KEEP TEMPERATURES WARMER THAN THE CLOUD FREE AREAS THIS
MORNING...AND HAVE MIN TEMPS IN THE UPPER TEENS TO MID 20S.
.LE..
LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 341 AM CST THU MAR 7 2013
CHALLENGING WEEKEND SYSTEM REMAINS THE FOCUS OF THE EXTENDED
FORECAST. THE LAST COUPLE RUNS OF THE GFS AND ECMWF HAVE MIGRATED
TOWARD A WEAKER...LESS PHASED UPPER WAVE LIFTING OUT OF THE SW.
BOTH DEPICT THE INITIAL UPPER LOW OVER THE FOUR CORNERS REGION
SATURDAY MORNING LIFTING NORTHEAST...PHASING WITH A NORTHERN STREAM
TROUGH AND SWEEPING NORTHEAST INTO SE CANADA. A SECONDARY PIECE OF
ENERGY BREAKS OFF AND STAYS TO THE SOUTH...MOVING THROUGH THE MID MS
VALLEY AND THEN OHIO RIVER VALLEY MONDAY. THIS WOULD PRODUCE A
WEAKER...LESS ORGANIZED SURFACE LOW THAT LIFTS NORTHEAST ALONG
THE PASSING COLD FRONT LATE SATURDAY NIGHT AND EARLY SUNDAY.
THE NET RESULT IS A FASTER SYSTEM...NOW MORE LIKELY TO EXIT THE AREA
BY SUNDAY EVENING WITH POSSIBLY LOWER QPF TOTALS FROM RAIN AND LESS
POTENTIAL FOR MEASURABLE SNOW BEHIND THE COLD FRONT.
FRIDAY NIGHT...ELEVATED WARM ADVECTION AND MOISTURE RETURN ON A
40 KT 850 MB JET MAY SPREAD SHOWERS INTO ESPECIALLY THE WESTERN HALF
OF THE FORECAST AREA AFTER MIDNIGHT. THERE REMAINS A POTENTIAL THAT
SURFACE TEMPERATURES MAY INITIALLY BE NEAR OR BELOW FREEZING ACROSS
THE NORTH AND NORTHEAST AND WILL KEEP A MENTION OF FREEZING RAIN.
SATURDAY SHOULD SEE PRECIPITATION DUE TO THE WARM ADVECTION AND
INCREASINGLY DIFFLUENT FLOW ALOFT...BUT AT THIS TIME IT LOOKS TO BE
MORE OF A SHOWERY NATURE. THE BEST POTENTIAL FOR WIDESPREAD RAIN
SHOULD BE IN THE WEST CLOSER TO THE APPROACHING FRONT WHERE POPS ARE
GREATEST. OTHERWISE...TEMPERATURES AND DEWPOINTS SHOULD RISE WELL
INTO THE 40S WITH SOUTHEAST WINDS LIKELY STRONG ENOUGH TO KEEP
ADVECTION FOG AT BAY. WIDESPREAD RAIN WILL BE FOCUSED ON SATURDAY
NIGHT WITH THE PASSAGE OF THE UPPER LEVEL WAVE AND THEN SURFACE COLD
FRONT TOWARD MORNING. WIDESPREAD QPF AMOUNTS OF .5 TO 1 INCH STILL
LOOK REASONABLE...WITH POSSIBLE LOCALLY HIGHER AMOUNTS IF ANY
CONVECTION TAKES PLACE. LINGERING SNOW COVER MAY EFFECTIVELY CAPTURE
MUCH OF THIS RAIN...WHICH WOULD DELAY OR PROLONG THE RUNOFF...WHILE
AT THE SAME TIME COULD ALSO LEAD TO MINOR URBAN FLOODING DUE TO
CLOGGED DRAINAGE. ANOTHER CONCERN WILL BE THE POTENTIAL FOR
WIDESPREAD FOG DUE TO LIGHT WINDS AND LOW LEVEL CONVERGENCE ALONG
THE FRONT AND PASSING WEAK SURFACE WAVE. HAVE ADDED FOG WORDING TO
THE FORECAST...BUT WILL HOLD OFF ON MENTIONING HYDRO CONCERNS UNTIL
CONFIDENCE OF HEAVIER QPF INCREASES.
SUNDAY...THE COLD FRONT IS NOW SHOWN EAST OF THE AREA BY MIDDAY WITH
LITTLE UPPER LEVEL FORCING POST FRONTAL AS THE UPPER TROUGH SHIFTS
EAST BY EVENING. COLD ADVECTION MAY CHANGE RAIN TO SNOW...BUT AT
THIS TIME IT LOOKS LIKE MINIMAL ACCUMULATIONS WITH ANY PRECIPITATION
LIKELY ENDING BY EARLY EVENING. ADVERTISED FORECAST HIGHS...IN THE
40S TO AROUND 50...WOULD OCCUR EARLY IN THE DAY...AND IF THE CURRENT
TIMING HOLDS...THESE NUMBERS MAY BE A CATEGORY OR TWO TO MILD.
MONDAY THROUGH WED...SURFACE HIGH PRESSURE AND NW FLOW ALOFT SHOULD
PROVIDE CONTINUED BELOW NORMAL TEMPERATURES. OUTSIDE OF A CLIPPER
SYSTEM CURRENTLY SHOWN PASSING WELL TO THE NORTH AROUND
TUESDAY...THERE WILL BE LITTLE POTENTIAL FOR PRECIPITATION.
SHEETS
AVIATION...(FOR THE 12Z TAFS THROUGH 12Z FRIDAY MORNING)
ISSUED AT 546 AM CST THU MAR 7 2013
STRATUS AND FOG TO DOMINATE THE AVIATION FORECAST THIS MORNING.
KMLI AND KBRL STILL AFFECTED BY MVFR STRATUS WITH CIGS AROUND
1800FT. THIS STRATUS IS HOLDING STEADY BUT SHOULD GRADUALLY MOVE
EAST IN THE MORNING AND SHOULD CLEAR AND RETURN TO VFR BETWEEN
15Z- 18Z. KCID AND KDBQ ARE NOT UNDER THE STRATUS BUT HAVE
DEVELOPED FOG WITH HIGHLY VARIABLE VISIBILITIES AND VERTICAL
VISIBILITIES. CONDITIONS ARE LIFR AT TIMES...BUT THIS SHOULD
DISSIPATE BY 16Z. VERY LIGHT WINDS TO TURN SOUTHEAST BUT REMAIN
LESS THAN 8KTS THROUGH THE PERIOD. FOG IS POSSIBLE AGAIN
TONIGHT...AND HAVE PUT SOME MVFR FOG INTO TERMINALS AFTER
08Z...THOUGH CONFIDENCE IN TIMING OR LOCATION IS NOT VERY HIGH.
.LE..
&&
.DVN WATCHES/WARNINGS/ADVISORIES...
IA...NONE.
IL...NONE.
MO...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS QUAD CITIES IA IL
1123 PM CST WED MAR 6 2013
.AVIATION...
A DIFFICULT CLEARING TREND WILL DOMINATE THE AVIATION FORECAST
EARLY TODAY OVER SOUTHEAST IOWA AND NEAR MLI...WITH CLEARING POSSIBLY
DELAYED UNTIL 12 TO 15Z. THE CIGS REMAIN MVFR
AROUND 1800 FT. WHILE CID AND DBQ ARE CLEAR...THEY WILL SEE A RISK
OF IFR TO LIFR FOG AND VV002 STRATUS DEVELOPMENT THROUGH
SUNRISE...MLI AND BRL SHOULD REMAIN CLOUDY ENOUGH THAT FOG DOES
NOT BECOME AN ISSUE. VERY LIGHT WINDS WILL LAST THROUGH THURSDAY
EVENING.
&&
.PREV DISCUSSION... /ISSUED 541 PM CST WED MAR 6 2013/
UPDATE...
SHORT TERM MODELS INCLUDING THE HRRR AND RAP13 CONTINUE TO
REPRESENT THE STRATUS FIELD BEST...AND BOTH SUGGEST IT WILL HANG
ON ALL NIGHT. AS SEEN ON SATELLITE TRENDS SINCE 430 PM...THE EDGE
OF THE STRATUS IS NO LONGER MOVING/DISSIPATING. IF IT IS...IT IS
NOW EXCRUCIATINGLY SLOW.
&&
.DVN WATCHES/WARNINGS/ADVISORIES...
IA...NONE.
IL...NONE.
MO...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS WICHITA KS
905 PM CST FRI MAR 8 2013
.UPDATE...
THE SCATTERED SHOWER CHANCES HAVE BEEN SLOW TO GET GOING ACROSS MOST
OF THE FORECAST AREA AT THIS TIME. WITH MAINLY SOME WIDELY SCATTERED
SPRITZES/SPRINKLES OR DRIZZLE. LOW LEVEL ISENTROPIC LIFT CONTINUES
TO LEAD TO LOTS OF LOW-MID CLOUDS WITH THIS LOW LEVEL SATURATION
LEADING TO GRADUALLY LOWER CEILINGS. THINK THE WIDESPREAD SHOWER
CHANCES WILL WAIT UNTIL THE INITIAL IMPULSE /THAT IS LEADING TO THE
LINE OF CONVECTION IN THE TX PANHANDLE/ BEGINS TO LIFT NORTHEAST
INTO SRN KS AFTER MIDNIGHT.. THINK AS THIS IMPULSE LIFTS
NORTH...SHOWERS WILL BECOME MORE WIDESPREAD FOR AREAS WEST OF
INTERSTATE 135...WHERE BETTER MOISTURE TRANSPORT IS ALREADY IN
PLACE. SHORT TERM RUC ALSO SHOWS SOME ELEVATED MUCAPE AROUND 400-600
J/KG MOVING INTO THIS AREA AS WELL...SO THINK SOME RUMBLES OF
EMBEDDED THUNDER MAY ALSO MOVE IN AS WELL. CURRENT GRIDS/ZONES LOOK
RIGHT ON TRACK...WITH POPS A LITTLE HIGH EARLY ON...BUT THEY LOOK
FINE FOR AFTER MIDNIGHT.
KETCHAM
&&
.PREV DISCUSSION... /ISSUED 558 PM CST FRI MAR 8 2013/
AVIATION...00Z TAFS KRSL/KSLN/KHUT/KICT/KCNU
MVFR CEILINGS WILL GRADUALLY MOVE INTO MOST OF THE TAF SITES THIS
EVENING. EXPECT DETERIORATING AVIATION CONDITIONS OVERNIGHT TO IFR
CONDITIONS BETWEEN 06-12Z/SAT AT MOST LOCATIONS AS WIDESPREAD
SHOWERS DEVELOP. COULD ALSO SEE SOME EMBEDDED THUNDER AS WELL FOR
MOST TAF LOCATIONS BETWEEN 12-18Z/SAT. THE DRY LINE ASSOCIATED WITH
THIS STORM SYSTEM WILL PUSH INTO THE KRSL/KHUT AND KICT TAF SITES
LATE IN THE TAF PERIOD...WHICH WILL SCOUR OUT THE IFR CEILINGS. THIS
DRYING OUT OF THE LOW LAYERS...AND SOME POSSIBLE HEATING DUE SOME
PEAKS OF SUNSHINE MAY ALSO LEAD TO A RENEWED CHANCE OF
THUNDERSTORMS...SO WILL INCLUDE A VCTS FOR THIS CHANCE FOR THE
KHUT/KRSL/KSLN AND KICT TAF SITES.
KETCHAM
PREV DISCUSSION... /ISSUED 328 PM CST FRI MAR 8 2013/
DISCUSSION...
FORECAST HIGHLIGHTS FOCUS AROUND PRECIPITATION CHANCES
TONIGHT-SUNDAY...INCLUDING THE POTENTIAL FOR A FEW STRONG SEVERE
STORMS SATURDAY AFTERNOON-EVENING...AND SNOW SATURDAY NIGHT-SUNDAY
MORNING.
IMPRESSIVE LOOKING UPPER LOW WITH QUITE A BIT OF LIGHTNING IS
CURRENTLY SPINNING OVER THE DESERT SOUTHWEST. AS THIS STORM SYSTEM
APPROACHES THE REGION TONIGHT...ANTICIPATING WIDESPREAD SHOWERS
WITH EMBEDDED THUNDERSTORMS TO BE ON THE INCREASE...ESPECIALLY
AFTER MIDNIGHT GENERALLY OVER CENTRAL AND SOUTH-CENTRAL KS. GIVEN
WEAK INSTABILITY...CANNOT RULE OUT SMALL HAIL WITH THE STRONGEST
STORMS. THIS WIDESPREAD SHIELD OF SHOWERS/THUNDERSTORMS WILL
GRADUALLY SHIFT EAST ACROSS THE AREA DURING THE DAY SATURDAY...IN
ZONE OF STRONG LOW TO MID-LEVEL WARM/MOIST ADVECTION AHEAD OF
APPROACHING UPPER WAVE.
BY TOMORROW MID-AFTERNOON...BRUNT OF MAIN PRECIPITATION SHIELD
SHOULD BE OVER THE EASTERN 1/3 OF KS...WITH SURFACE DRYLINE HANGING
BACK WESTWARD OVER CENTRAL/SOUTH-CENTRAL KS...AND COOLING/DRYING
ALOFT OVERSPREADING THE WARM SECTOR AHEAD OF APPROACHING SHORTWAVE.
IF BREAKS IN OVERCAST CAN DEVELOP ALLOWING SOME HEATING IN WAKE OF
MAIN PRECIPITATION SHIELD...THINKING THERE COULD BE A WINDOW OF
OPPORTUNITY FROM MID-AFTERNOON THROUGH EARLY EVENING FOR SCATTERED
SHALLOW/LOW-TOPPED SURFACE BASED CONVECTION GENERALLY ALONG/WEST OF
I-135 CORRIDOR. IF ENOUGH INSTABILITY CAN MATERIALIZE FOR
STORMS...LOW-TOPPED SUPERCELLS WILL BE POSSIBLE GIVEN STRONGLY
SHEARED ENVIRONMENT...WITH THE POTENTIAL FOR SOME LARGE HAIL.
ADDITIONALLY...NAM BUFR SOUNDINGS INDICATE DECENT LOW-LEVEL CAPE
OWING TO MID-UPPER 50F DEWPOINTS AND STEEPENING LAPSE RATES...WHICH
WOULD SUPPORT THE POTENTIAL FOR AN ISOLATED TORNADO OR TWO. WILL NOT
COMPLETELY BITE ONTO THE OMINOUS NAM SOLUTION JUST YET GIVEN
AFTERNOON HEATING/INSTABILITY QUESTIONS...BUT DEFINITELY SOMETHING
FOR THE NIGHT SHIFT TO EVALUATE FURTHER.
BY SATURDAY NIGHT-EARLY SUNDAY...AS UPPER LOW SHIFTS EAST AND MUCH
COLDER AIR FILTERS SOUTH...THINKING CENTRAL KS COULD SEE A PERIOD OF
LIGHT SNOW. CURRENT INDICATIONS SUGGEST HEAVIEST SNOW WILL REMAIN
OFF TO THE NORTH/NORTHWEST...BUT PORTIONS OF CENTRAL KS COULD
RECEIVE UP TO 1 INCH OR SO AFTER MIDNIGHT SATURDAY NIGHT THROUGH
SUNDAY MORNING. SUNDAY WILL LIKELY BE THE COLDEST DAY OF THE NEXT
7-10 DAYS...WITH HIGHS IN THE 30S-40S AND A STOUT NORTH WIND.
GIVEN CURRENT MODEL CONSENSUS...CONFIDENCE IS MODERATE TO HIGH THAT
DRY AND WARMING CONDITIONS WILL PREVAIL MONDAY THROUGH NEXT
WEEKEND...AS MID/UPPER FLOW FLATTENS OUT SOME AND ATMOSPHERIC
HEIGHTS/THICKNESS INCREASES. HIGHS IN THE 50S-60S APPEAR LIKELY.
ADK
&&
.PRELIMINARY POINT TEMPS/POPS...
WICHITA-KICT 52 62 35 40 / 70 80 40 30
HUTCHINSON 52 63 33 39 / 70 70 40 40
NEWTON 51 61 33 38 / 70 80 50 40
ELDORADO 51 60 35 41 / 70 80 50 30
WINFIELD-KWLD 52 61 37 42 / 70 80 50 20
RUSSELL 52 65 29 38 / 50 50 60 60
GREAT BEND 53 67 30 39 / 50 50 60 60
SALINA 52 63 32 38 / 60 70 50 50
MCPHERSON 52 63 32 38 / 70 70 50 50
COFFEYVILLE 53 61 44 46 / 50 90 70 30
CHANUTE 51 59 42 44 / 50 90 70 40
IOLA 50 59 41 44 / 50 90 70 40
PARSONS-KPPF 52 60 42 45 / 50 90 70 30
&&
.ICT WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS GOODLAND KS
252 AM MST THU MAR 7 2013
.SHORT TERM...(TODAY THROUGH SATURDAY NIGHT)
ISSUED AT 248 AM MST THU MAR 7 2013
A RIDGE WILL BE OVER THE PLAINS TODAY AND TONIGHT AND THEN SHIFT
EAST FRIDAY. SOUTHWEST FLOW WILL BE OVER THE CENTRAL PLAINS FRIDAY
NIGHT WITH AN UPPER LOW OVER NORTHERN ARIZONA. THE UPPER LOW WILL
MOVE INTO SOUTHEAST COLORADO SATURDAY AND INTO SOUTHEAST NEBRASKA
SATURDAY NIGHT. A SURFACE TROUGH WILL MOVE INTO EASTERN COLORADO
TODAY AND TONIGHT. BY FRIDAY A LARGE AREA OF LOW PRESSURE WILL
RESIDE OVER THE ROCKIES. A SURFACE LOW WILL BE CENTERED OVER EASTERN
COLORADO/NORTHWEST FRIDAY NIGHT AND SATURDAY. THE LOW WILL SHIFT
INTO NORTHEAST KANSAS SATURDAY NIGHT.
DRY WEATHER WILL CONTINUE TODAY THROUGH FRIDAY. BOUNDARY LAYER RH
ABOVE 90 PERCENT WILL BE FAVORABLE FOR FOG DEVELOPMENT TONIGHT
AND EARLY FRIDAY MORNING ACROSS MOST OF THE FA. DYNAMICS START
AFFECTING THE FA FRIDAY NIGHT BUT MOISTURE IS MARGINAL. THE GFS
SHOWS A DRY SLOT OVERTAKING NEARLY ALL OF THE FA FRIDAY NIGHT
EXCEPT FOR THE FAR NORTHWEST ZONES. FOR THIS REASON HAVE LOWERED
POPS SOME. INSTABILITY DOES NOT LOOK AS WIDESPREAD SO HAVE KEPT
THAT EAST OF THE COLORADO BORDER. FORECAST SOUNDINGS INDICATE SOME
STRATUS AND POSSIBLY FOG MAINLY ACROSS THE NORTHEAST ZONES. THE
DRY SLOT CONTINUES TO AFFECT THE FA SATURDAY MORNING SO HAVE
REDUCED POPS SOME. THE DRY SLOT SHIFTS EAST OF THE FA SATURDAY
AFTERNOON. GOOD MOISTURE MOVES INTO THE FA SO PLAN TO KEEP CURRENT
HIGH CHANCE AND LIKELY POPS. ISOLATED THUNDER WILL REMAIN IN THE
FORECAST BUT WILL SLOWLY SHIFT INTO THE EASTERN FA BY AFTERNOON.
WRAPAROUND SNOW WILL SPREAD ACROSS THE ENTIRE FA SATURDAY NIGHT.
WINDS WILL BE STRONG ENOUGH FOR BLOWING SNOW AS WELL. AT THIS TIME
IT APPEARS THAT TOTAL SNOW AMOUNTS SHOULD VARY AROUND 3 INCHES FOR
THE EVENT. SNOW SHOULD START DECREASING SOME LATE SATURDAY NIGHT.
MAX TEMPERATURES SHOULD RISE INTO THE LOWER TO MID 60S TODAY OVER
THE SOUTHWEST HALF OF THE FA WITH LOWER 50S IN THE EXTREME NORTHEAST
FA. TEMPERATURES FRIDAY WILL BE COOLER WITH READINGS IN THE MID 50S.
THE WEST WILL BE COLDER WITH UPPER 30S AND THE SOUTHEAST WILL REACH
INTO THE LOWER 50S. MIN TEMPERATURES TONIGHT WILL BE IN THE UPPER
20S/LOWER 30S. LOWS FRIDAY NIGHT WILL BE EVEN WARMER WITH READINGS
IN THE UPPER 30S WEST TO LOWER 40S EAST. LOW TEMPERATURES SATURDAY
NIGHT WILL BE IN THE MID AND UPPER 20S.
.LONG TERM...(SUNDAY THROUGH THURSDAY)
ISSUED AT 1147 PM MST WED MAR 6 2013
SNOW WILL BE WINDING DOWN ON SUNDAY WITH ADDITIONAL ACCUMULATIONS
OF LESS THAN AN INCH EXPECTED. HOWEVER...NORTHERLY WINDS WILL BE
GUSTY AND RESULT IN AREAS OF BLOWING SNOW. SNOW WILL END BY SUNDAY
NIGHT. THE REMAINDER OF THE PERIOD WILL BE DOMINATED BY UPPER
RIDGING BUILDING ACROSS THE ROCKIES...RESULTING IN DRY CONDITIONS
AND WARMING TEMPERATURES.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z THURSDAY NIGHT)
ISSUED AT 1030 PM MST WED MAR 6 2013
POTENTIAL FOR OVERNIGHT FOG/STRATUS CONTINUES...WITH BEST CHANCES
FOR REDUCTIONS IN FLIGHT CATEGORIES AT MCK. CONFIDENCE SOMEWHAT
LOW ATTM THOUGH AS 00Z RAOBS AND RAP DATA LOWER CONFIDENCE IN HOW
WIDESPREAD FOG POTENTIAL WILL BE. FOR THE TIME BEING...BROUGHT MCK
DOWN TO MIDDLE OF THE ROAD/OPERATIONAL SIGNIFICANT MVFR FOR A
PORTION OF THE OVERNIGHT HOURS. OTHERWISE...VFR CONDITIONS
EXPECTED FOR THE REST OF THE PERIOD.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
CO...NONE.
NE...NONE.
&&
$$
SHORT TERM...032
LONG TERM...024
AVIATION...JRM
AREA FORECAST DISCUSSION
NWS GOODLAND KS
1150 PM MST WED MAR 6 2013
.SHORT TERM...(THIS EVENING THROUGH THURSDAY)
ISSUED AT 218 PM MST WED MAR 6 2013
AS OF 3 PM CST...2 PM MST...SKIES WERE MOSTLY CLEAR TO PARTLY CLOUDY
AS SOME HIGH LEVEL CIRRUS MOVES FROM WEST TO EAST. TEMPERATURES
RANGED FROM THE LOW 40S NEAR NORTON...KANSAS TO NEAR 60 DEGREES IN
TRIBUNE...KANSAS. WINDS WERE GENERALLY FROM THE SOUTHEAST AT 15 TO
20 MPH WITH GUSTS UP TO 25 OR 30 MPH. A LEE TROUGH WAS DEVELOPING
ACROSS EAST CENTRAL COLORADO.
FOR TONIGHT...BREEZY SOUTHEAST WINDS WILL WEAKEN THIS EVENING. WINDS
WILL BACK TO THE EAST OVER THE EASTERN FORECAST AREA...ALLOWING AIR
WITH HIGHER MOISTURE CONTENT TO FILTER INTO THE AREA. LOW
TEMPERATURES WILL DROP INTO THE LOW 20S. WITH LIGHT WINDS...HIGHER
DEWPOINTS AND COLD TEMPERATURES...FOG IS EXPECTED TO DEVELOP ACROSS
A LARGE AREA TONIGHT. ACROSS THE WESTERN FORECAST AREA...A LEE
TROUGH TO THE WEST WILL MOVE TO THE EAST. WINDS WILL BE LIGHT AND
VARIABLE JUST EAST OF THE TROUGH AND FROM THE WEST OR NORTHWEST AT
5-10 MPH AS THE TROUGH MOVES IN. THIS SHOULD KEEP THE FOG FROM
ADVANCING INTO EASTERN COLORADO. FOG COULD BE DENSE...BUT WAS NOT
CONFIDENT ENOUGH TO PLACE THIS INTO THE FORECAST AT THE CURRENT TIME.
TEMPERATURES WILL BE HIGHLY VARIABLE ACROSS THE FORECAST AREA FOR
TOMORROW. HIGHS ACROSS MOST OF EASTERN COLORADO AND PORTIONS OF
NORTHWEST KANSAS WILL BE IN THE MID 60S TO NEAR 70 IN SOME SPOTS.
FOG AND CLOUDS WILL LINGER INTO THE LATE MORNING HOURS FOR NORTHEAST
PORTIONS OF THE FORECAST AREA. THIS WILL KEEP HIGH TEMPERATURES
CONFINED TO THE LOWER 50S NEAR MCCOOK NEBRASKA AND HILL CITY KANSAS.
LIGHT AND VARIABLE WINDS IN THE MORNING WILL BECOME SOUTHEAST AT 10
TO 15 MPH DURING THE AFTERNOON HOURS.
AT THIS TIME...FIRE WEATHER IS NOT EXPECTED TO BECOME A CONCERN FOR
TOMORROW. RELATIVE HUMIDITIES WILL DROP INTO THE 15 TO 25 PERCENT
RANGE FOR CHEYENNE AND KIT CARSON COUNTIES IN COLORADO AND
SHERMAN...WALLACE AND GREELEY COUNTIES IN KANSAS. HOWEVER...LIGHT
WINDS ARE EXPECTED WHICH WILL REDUCE THE FIRE WEATHER DANGER FOR
TOMORROW AFTERNOON.
.LONG TERM...(SUNDAY THROUGH THURSDAY)
ISSUED AT 1147 PM MST WED MAR 6 2013
SNOW WILL BE WINDING DOWN ON SUNDAY WITH ADDITIONAL ACCUMULATIONS
OF LESS THAN AN INCH EXPECTED. HOWEVER...NORTHERLY WINDS WILL BE
GUSTY AND RESULT IN AREAS OF BLOWING SNOW. SNOW WILL END BY SUNDAY
NIGHT. THE REMAINDER OF THE PERIOD WILL BE DOMINATED BY UPPER
RIDGING BUILDING ACROSS THE ROCKIES...RESULTING IN DRY CONDITIONS
AND WARMING TEMPERATURES.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z THURSDAY NIGHT)
ISSUED AT 1030 PM MST WED MAR 6 2013
POTENTIAL FOR OVERNIGHT FOG/STRATUS CONTINUES...WITH BEST CHANCES
FOR REDUCTIONS IN FLIGHT CATEGORIES AT MCK. CONFIDENCE SOMEWHAT
LOW ATTM THOUGH AS 00Z RAOBS AND RAP DATA LOWER CONFIDENCE IN HOW
WIDESPREAD FOG POTENTIAL WILL BE. FOR THE TIME BEING...BROUGHT MCK
DOWN TO MIDDLE OF THE ROAD/OPERATIONAL SIGNIFICANT MVFR FOR A
PORTION OF THE OVERNIGHT HOURS. OTHERWISE...VFR CONDITIONS
EXPECTED FOR THE REST OF THE PERIOD.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
CO...NONE.
NE...NONE.
&&
$$
SHORT TERM...RRH
LONG TERM...024
AVIATION...JRM
AREA FORECAST DISCUSSION
NWS GOODLAND KS
1032 PM MST WED MAR 6 2013
.SHORT TERM...(THIS EVENING THROUGH THURSDAY)
ISSUED AT 218 PM MST WED MAR 6 2013
AS OF 3 PM CST...2 PM MST...SKIES WERE MOSTLY CLEAR TO PARTLY CLOUDY
AS SOME HIGH LEVEL CIRRUS MOVES FROM WEST TO EAST. TEMPERATURES
RANGED FROM THE LOW 40S NEAR NORTON...KANSAS TO NEAR 60 DEGREES IN
TRIBUNE...KANSAS. WINDS WERE GENERALLY FROM THE SOUTHEAST AT 15 TO
20 MPH WITH GUSTS UP TO 25 OR 30 MPH. A LEE TROUGH WAS DEVELOPING
ACROSS EAST CENTRAL COLORADO.
FOR TONIGHT...BREEZY SOUTHEAST WINDS WILL WEAKEN THIS EVENING. WINDS
WILL BACK TO THE EAST OVER THE EASTERN FORECAST AREA...ALLOWING AIR
WITH HIGHER MOISTURE CONTENT TO FILTER INTO THE AREA. LOW
TEMPERATURES WILL DROP INTO THE LOW 20S. WITH LIGHT WINDS...HIGHER
DEWPOINTS AND COLD TEMPERATURES...FOG IS EXPECTED TO DEVELOP ACROSS
A LARGE AREA TONIGHT. ACROSS THE WESTERN FORECAST AREA...A LEE
TROUGH TO THE WEST WILL MOVE TO THE EAST. WINDS WILL BE LIGHT AND
VARIABLE JUST EAST OF THE TROUGH AND FROM THE WEST OR NORTHWEST AT
5-10 MPH AS THE TROUGH MOVES IN. THIS SHOULD KEEP THE FOG FROM
ADVANCING INTO EASTERN COLORADO. FOG COULD BE DENSE...BUT WAS NOT
CONFIDENT ENOUGH TO PLACE THIS INTO THE FORECAST AT THE CURRENT TIME.
TEMPERATURES WILL BE HIGHLY VARIABLE ACROSS THE FORECAST AREA FOR
TOMORROW. HIGHS ACROSS MOST OF EASTERN COLORADO AND PORTIONS OF
NORTHWEST KANSAS WILL BE IN THE MID 60S TO NEAR 70 IN SOME SPOTS.
FOG AND CLOUDS WILL LINGER INTO THE LATE MORNING HOURS FOR NORTHEAST
PORTIONS OF THE FORECAST AREA. THIS WILL KEEP HIGH TEMPERATURES
CONFINED TO THE LOWER 50S NEAR MCCOOK NEBRASKA AND HILL CITY KANSAS.
LIGHT AND VARIABLE WINDS IN THE MORNING WILL BECOME SOUTHEAST AT 10
TO 15 MPH DURING THE AFTERNOON HOURS.
AT THIS TIME...FIRE WEATHER IS NOT EXPECTED TO BECOME A CONCERN FOR
TOMORROW. RELATIVE HUMIDITIES WILL DROP INTO THE 15 TO 25 PERCENT
RANGE FOR CHEYENNE AND KIT CARSON COUNTIES IN COLORADO AND
SHERMAN...WALLACE AND GREELEY COUNTIES IN KANSAS. HOWEVER...LIGHT
WINDS ARE EXPECTED WHICH WILL REDUCE THE FIRE WEATHER DANGER FOR
TOMORROW AFTERNOON.
.LONG TERM...(THURSDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 205 PM MST WED MAR 6 2013
THURSDAY NIGHT-FRIDAY...UPPER LOW CENTER JUST OFF THE CALIFORNIA
COAST AT THE BEGINNING OF THE PERIOD MOVING SOUTHEAST TOWARD THE
SOUTHERN TIP OF CALIFORNIA/SOUTHWEST ARIZONA AREA BY 00Z SATURDAY.
AT THE SURFACE LOW PRESSURE SLOWLY DEEPENS IN SOUTHEAST COLORADO
THROUGH THE PERIOD. STRATUS/FOG EXPECTED ACROSS THE NORTHEAST 1/2 OF
THE AREA MID THURSDAY NIGHT EXPANDING SOUTHWESTWARD BY 12Z FRIDAY AS
WINDS TURN NORTHEAST IN RESPONSE TO DEEPENING LOW. STRATUS/FOG
SHOULD RETREAT NORTH AND EAST FRIDAY AFTERNOON BUT COULD STILL POSE
A PROBLEM ACROSS THE FAR EAST AND NORTHEAST WHERE BOUNDARY LAYER RH
STILL HIGH. OTHERWISE SHOULD SEE AN INCREASE IN CLOUDINESS MOVING IN
FROM THE SOUTHWEST AHEAD OF UPPER LOW. NOT TERRIBLY CONFIDENT IN
PRECIPITATION CHANCES FRIDAY BUT ALSO CANT RULE IT OUT EITHER. HAVE
KEPT SLIGHT CHANCE POPS GOING FOR NOW. THERE IS SOME INSTABILITY
THAT MOVES IN FROM THE SOUTH DURING THE AFTERNOON AS WELL AS NOSE OF
UPPER JET. WILL KEEP THUNDER MENTION GOING AS WELL. LOWS MID 20S
TO LOW 30S WITH HIGHS LOW TO MID 50S NORTH OF I-70...UPPER 50S TO
MID 60S SOUTH.
FRIDAY NIGHT-SATURDAY...12Z GFS/NAM/09Z SREF BRING UPPER LOW OVER
FORECAST AREA BY 00Z SUNDAY WITH 00Z ECWMF A BIT SLOWER OVER NORTH
CENTRAL NEW MEXICO. FOR FRIDAY NIGHT MID LEVEL DRY SLOT TRIES TO
WORK ITS WAY INTO THE AREA AFTER MIDNIGHT WITH BETTER PRECIPITATION
CHANCES GENERALLY NORTH OF INTERSTATE 70 AND BETTER ALONG THE
NEBRASKA/KANSAS BORDER. PREVIOUS FORECAST HAD THE GENERAL IDEA JUST
TWEAKED POPS DOWN A BIT WHERE CONFIDENCE HIGHER IN WHERE DRY SLOT
WOULD BE. STRATUS/FOG WILL BE A CONCERN AS WELL AND ADDED TO
FORECAST. UPPER JET OVER THE AREA WITH GOOD DIVERGENCE. STILL SOME
WEAK INSTABILITY OVER THE AREA SO HAVE ALSO KEPT SMALL CHANCE FOR
THUNDERSTORMS. FOR SATURDAY SFC LOW MOVES INTO CENTRAL OR SOUTHWEST
KANSAS DEPENDING ON THE MODEL CHOICE. DRY SLOT WORKS ITS WAY EAST
LIMITING PRECIP POTENTIAL WHILE FURTHER WEST/NORTHWEST WRAPAROUND
PRECIPITATION MOVES IN. LOWERED POPS A BIT WHERE DRY SLOT EXPECTED
BUT WITH DIFFERENCES IN OPINION MODEL WISE DIDNT GET TOO SPECIFIC AS
CONFIDENCE NOT TERRIBLY HIGH. DEFINING RAIN/SNOW LINE ALSO DEPENDENT
ON SFC LOW LOCATION AND EXTENT OF WRAPAROUND PRECIP. AGAIN WILL TRY
AND BLEND MODEL SOLUTIONS FOR NOW. LOW TEMPERATURES MILD IN THE
MID 30S TO MID 40S. HIGHS SATURDAY LOW 40S FAR NORTHWEST...50-60
ELSEWHERE...WARMEST FROM HILL CITY TO LEOTI.
SATURDAY NIGHT-SUNDAY NIGHT...MODELS COMING INTO BETTER AGREEMENT.
UPPER LOW EXPECTED TO MOVE SLOWLY EAST/NORTHEAST AS UPPER RIDGE
BUILDS IN FROM THE WEST. BEST CHANCE OF ACCUMULATING SNOW LOOKS TO
BE SATURDAY NIGHT AS COLDER AIR MOVES IN FROM THE WEST/NORTHWEST ON
THE BACKSIDE OF THE LOW. NORTH WINDS WILL ALSO INCREASE PRODUCING
SOME BLOWING SNOW AND REDUCED VISIBILITIES. ON SUNDAY SNOW WILL
DECREASE FROM WEST TO EAST AND SHOULD BE OUT OF THE AREA SUNDAY
NIGHT. LOWS SATURDAY NIGHT IN THE MID 20S TO LOW 30S...FALLING INTO
THE UPPER TEENS TO LOW 20S SUNDAY NIGHT. HIGHS SUNDAY IN THE 30S.
MONDAY-WEDNESDAY...WARMING TREND COMMENCES WITH SLIGHTLY BELOW
NORMAL TEMPERATURES MONDAY AND ABOVE NORMAL TEMPERATURES TUESDAY AND
WEDNESDAY.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z THURSDAY NIGHT)
ISSUED AT 1030 PM MST WED MAR 6 2013
POTENTIAL FOR OVERNIGHT FOG/STRATUS CONTINUES...WITH BEST CHANCES
FOR REDUCTIONS IN FLIGHT CATEGORIES AT MCK. CONFIDENCE SOMEWHAT
LOW ATTM THOUGH AS 00Z RAOBS AND RAP DATA LOWER CONFIDENCE IN HOW
WIDESPREAD FOG POTENTIAL WILL BE. FOR THE TIME BEING...BROUGHT MCK
DOWN TO MIDDLE OF THE ROAD/OPERATIONAL SIGNIFICANT MVFR FOR A
PORTION OF THE OVERNIGHT HOURS. OTHERWISE...VFR CONDITIONS
EXPECTED FOR THE REST OF THE PERIOD.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
CO...NONE.
NE...NONE.
&&
$$
SHORT TERM...RRH
LONG TERM...99
AVIATION...JRM
AREA FORECAST DISCUSSION
NWS LOUISVILLE KY
1216 PM EST THU MAR 07 2013
...Updated Aviation Discussion...
.Forecast Update...
Issued at 1059 AM EST Wed Mar 5 2013
Morning satellite imagery shows widespread low clouds across the
forecast area this morning. Combination of inversion aloft along
with light winds will keep the low clouds socked in for much of the
day. Some very light drizzle and snow flurries will be possible in
areas throughout the day as well. With the expected cloud cover to
persist, have adjusted temperatures down several degrees to account
for the loss of solar insolation. Highs probably will only top out
in the lower 30s in the east with mid to upper 30s across the
central and west.
Updated forecast products are in production and will be available
shortly.
&&
.Short Term (Now - Friday)...
Issued at 305 AM EST Thu Mar 7 2013
Although a few flurries or instances of drizzle aren`t out of the
realm of possibilities this morning, believe most areas should be
dry through the short term period. Sfc high pressure and upper
level ridging will work into the area through Friday. The main
short term challenges will be the exit of low level stratus this
afternoon/evening and temperatures.
For today, think that the morning hours will remain cloudy. Latest
model runs keep pushing back the erosion of stratus across the area
which makes sense...thick stratus is stubborn to erode in most
cases. Thus, think that south central KY may see some sunshine by
mid afternoon, but southern Indiana and north central KY will stay
cloudy for much of the day. For the northern portions of the area,
clouds will likely erode sometime this evening from SW to NE.
Tonight and Friday should be mostly clear or only partly cloudy.
As for temperatures, think that low clouds will prohibit much of a
diurnal rise today except for maybe in south central KY where
stratus is expected to become more scattered in nature. Thus, have
gone below guidance for high temps over much of the area today. A
good temp gradient will likely set up along the edge of the stratus
deck which will be tough to nail down. Highs should range from the
upper 30s to mid 40s from NE to SW.
For tonight, think we`ll see good cooling with light northeasterly
winds and clear skies in place. Low temps should fall into the low
to mid 20s.
Friday will feature plenty of sunshine and temperatures warming into
the upper 40s and lower 50s.
.Long Term (Friday Night through Wednesday)...
Issued at 315 AM EST Thu Mar 7 2013
Friday Night - Saturday Night...
Upper level ridge axis will be directly overhead Friday night, with
surface high pressure anchored over the eastern Great Lakes. These
two features will slide east, albeit slowly due to downstream
blocking, through the majority of the weekend. This will set the
stage for a dry and much milder period of weather. Friday night lows
will be slightly below normal for this time of year due to good
radiational cooling conditions, however temperatures will quickly
recover on Saturday into the upper 50s and low 60s across the
region. Saturday Night will feature much milder lows as steady
southerly flow sets in between high to our east and the next
developing storm system to our west. Lows will only drop to the
40-45 degree range. One thing worth noting, is that models have sped
up with respect to first wave of warm advection rainfall around dawn
on Sunday. Will leave western fringes dry for now, but may
eventually have to introduce small chances of measurable rain very
late in the period Saturday night due to the isentropic lift regime
that will be in place.
Sunday - Tuesday...
By Sunday, upper level ridge axis will be along the Atlantic Coast
with split upper level flow across the western two-thirds of the
CONUS. Broad southwest flow aloft will develop over the region
between ridging to our east and troughing over the SW CONUS, with
elongated surface trough/boundary just to our west.
The trend has continued to be faster with precipitation arrival on
Sunday, however confidence is not all that high due to split upper
level flow and general inconsistency in model performance to this
point. Don`t want to totally buy into how fast models are with the
system yet due to the downstream blocking, and tendency for more
amplified/slower overall progression of systems. Nevertheless, have
introduced 30-40 percent chances of rain mainly across southern
Indiana for Sunday. Sunday will continue the warming trend as steady
southerly flow persists and temperatures jump into the low and mid
60s, however will stay away from the warmest guidance as increasing
cloud cover and perhaps some precipitation will keep temps down
slightly.
Periodic rain will be likely for Sunday night and Monday as a couple
of waves ride along a slowly eastward progressing boundary oriented
nearly parallel to the upper level flow. Could end up getting a
pretty decent amount of rainfall as the system will be slow and
PWATS up around 1.25" through the column overspread the region. Will
continue to leave thunder out as thermal profiles are moist
adiabatic at best, however will continue to monitor.
The frontal boundary looks to move through by Monday
afternoon/evening with precipitation beginning to taper off Monday
night. Will only keep lingering pops in the east on Tuesday. Still
keeping any snow mention out of the forecast as cold air does not
look to catch up to deep moisture in time, but this will be another
portion of the forecast that needs continued monitoring. Lows Monday
and Tuesday nights will be in the mid and upper 30s, with highs on
Tuesday and Wednesday in the upper 40s to around 50.
&&
.Aviation (18Z TAF Issuance)...
Issued at 1215 PM EST Thu Mar 7 2013
Main TAF issue through the period will be the lingering low-level
stratus deck across the region. Strong capping inversion aloft is
keeping the low-level moisture locked in place. While the latest
NAM and GFS runs are suggestive of the clouds scouring out this
afternoon, it seems more likely that it will be later tonight before
things clear out in earnest. Given that the RAP model seems to have
a pretty good handle on things, plan on leaving the MVFR cigs in the
forecast for this afternoon and a good part of the evening and into
the overnight period. It is very possible that we may not scour out
to VFR until Friday morning. However, we`ll continue to look at
future datasets and adjust the forecast as necessary. Winds will be
light across the region and out of the north and northwest. Winds
will gradually shift to the northeast tonight and remain light.
&&
.LMK WATCHES/WARNINGS/ADVISORIES...
IN...NONE.
KY...NONE.
$$
Update...........MJ
Short Term.......AMS
Long Term........BJS
Aviation.........MJ
AREA FORECAST DISCUSSION
NWS WAKEFIELD VA
1226 AM EST THU MAR 7 2013
.SYNOPSIS...
LOW PRESSURE MOVES FURTHER OUT TO SEA THIS MORNING. HIGH PRESSURE
BUILDS INTO THE AREA THIS AFTERNOON INTO THE WEEKEND.
&&
.NEAR TERM /UNTIL 6 AM THIS MORNING/...
INTENSE LOW PRS CONTS TO MOVE FRTR OFFSHORE ATTM. ONLY PCPN LEFT
WAS ALONG THE IMMEDIATE COASTS WITH A MIX OF RAIN/SNOW SHWRS.
LATEST DATA SHOWING M CLR SKIES W OF I95. DESPITE GUSTS OVR 30 MPH
ALONG THE COASTS...WNDS HAVE DMNSHD BELOW WND ADVSRY CRITERIA PAST
FEW HRS SO HAVE DROPPED THE ADVSRY ALL CSTL AREAS XCPT AT ORF/VA
BCH/CURRITUCK NC WHERE GUSTS AOA 40 KTS CONT. LOWS U20S-M30S.
&&
.SHORT TERM /6 AM THIS MORNING THROUGH SATURDAY/...
LO PRES CONTS TO MOVE OUT TO SEA THU THROUGH SAT. A SECOND S/W
DIVING SSE FM WRN NEW ENG/NY STATE ON FRI PSBLY RESULTING IN
BKN/OVC CLDNS (ESP E OF I 95) AND ISOLD/SCT PCPN. NNW WINDS WILL
RMN GUSTY AS WELL...ESP NR THE CST...THROUGH FRI. SFC HI PRES IS
SLO TO BUILD SWD INTO THE MDATLC RGN BY SAT...FINALLY RESULTING IN
DRY WX FOR ALL AREAS.
P/MCLDY TNGT...THEN PCLDY OR VRB CLDNS THU. PCLDY W/MCLDY E THU
NGT THROUGH FRI...THEN MSTLY SKC ON SAT. HI TEMPS RANGING THROUGH
THE 40S N AND CNTRL AREAS...TO L50S S THU/FRI...THEN FM THE U40S
TO M50S SAT. LO TEMPS IN THE U20S TO L30S THU/FRI NGTS.
&&
.LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/...
GOING WITH A COMBINATION OF THE 12Z GFS/ECMWF FOR THE EXTENDED
PERIOD...ESPLY WITH REGARD TO TIMING OF APPROACH AND PASSAGE OF COLD
FRONT MON NGT THRU TUE. UA RDG/LRG AREA OF SFC HI PRES WILL PROVIDE
DRY WX SAT NGT INTO MON MORNG. LO PRES AND ASSOC COLD FRONT WILL
THEN AFFECT THE REGION MON EVENG THRU TUE...WITH DECENT CHC FOR
SHOWERS. MILDER TEMPS EXPECTED SUN INTO TUE. DRY WX RETURNS FOR TUE
NGT THRU WED...AS HI PRES WILL GRADUALLY BLD IN FM THE NW. MIN TEMPS
WILL BE IN THE LWR TO MID 30S SUN MORNG...IN THE UPR 30S TO LWR 40S
MON MORNG...IN THE 40S TUE MORNG...AND IN THE MID 30S TO ARND 40 WED
MORNG. MAX TEMPS WILL BE IN THE MID 50S TO LWR 60S SUN...IN THE LWR
TO MID 60S MON...IN THE MID 50S TO LWR 60S TUE...AND IN THE MID TO
UPR 50S WED.
&&
.AVIATION /05Z THURSDAY THROUGH MONDAY/...
LOW PRESSURE HAS MOVED OFF THE VA/NC COAST AND STRONG WINDS ARE
GUSTING FROM THE N/NNW AT ALL TAF SITES. GUSTS TO 40-45 KT REMAIN
PSBL AT TIMES THROUGH THE OVERNIGHT HOURS...ESPECIALLY ALONG THE COAST.
RAIN AND SNOW WILL TAPER OFF TONIGHT. CIGS AND VSBYS WILL CONTINUE
TO BE IN AND OUT OF IFR CONDS WITH MAINLY IFR ON THE BACKSIDE OF
THE LOW. PCPN ENDS AND DRYING WILL ALLOW CIGS TO IMPROVE AFT 05Z.
VFR CONDS ARE EXPECTED TOWARD MORNING WITH WINDS GUSTING TO 25KT
IN THE AFTN.
THE LOW WILL CONTINUE TO SLOWLY PUSH OFFSHORE ALLOWING HIGH PRESSURE
TO BUILD IN FROM THE NW. FAIR WEATHER/VFR CONDITIONS WILL PREVAIL
INTO EARLY NEXT WEEK WITH GUSTY WINDS CONTINUING DUE TO THE STRONG
PRESSURE GRADIENT THAT WILL REMAIN OVER THE AREA.
&&
.MARINE...
UPDATE: HAVE HOISTED STORM WARNING FOR ATLANTIC COASTAL WATERS
NORTH OF VA/NC BORDER. HAVE BEEN HANDLING WITH SPECIAL MARINE
WARNINGS THUS FAR, BUT WITH HRRR SHOWING THIS SURGE LASTING A FEW
HOURS LONGER, FEEL A BIT MORE COMFORTABLE HOISTING STORM HEADLINE
THROUGH 2AM, WITH A PERIOD OF GALES LIKELY AFTER WINDS DIMINISH
SOME AFTER MIDNIGHT. OTHERWISE, HAVE DROPPED GALES OVER THE RIVERS
TO SCA...IN EFFECT UNTIL MORNING.
PREVIOUS DISCUSSION....
A STRENGTHENING SFC LOW PRESSURE WILL ROTATE OVER THE MID
ATLANTIC COAST THIS EVENING...THEN PUSH OUT TO SEA OVERNIGHT.
WIND DIRECTIONS ARE PRIMARILY N LATE THIS AFTN AND WILL BECOME
MORE NWLY AS THE EVENING PROGRESSES. A NRLY SURGE HAS BEGUN OVER
NRN CHES BAY AND WILL CONTINUE TO PUSH SWD THROUGH THE EVENING.
CURRENT FORECAST ALREADY HAS THIS TREND IN PLACE. FOR COASTAL
WATERS N OF CHINCOTEAGUE...A STORM WARNING HAS BEEN ISSUED THROUGH
EARLY THU MORNING AS THE NRLY SURGE COMMENCES LATE THIS AFTN INTO
THE EVENING AND GUSTS REACH 50-55 KT. IN ADDITION...GALE WARNINGS
HAVE BEEN ISSUED FOR THE RIVERS TO ACCOUNT FOR THE NRLY SURGE AND
FOR WHEN WINDS BECOME NWLY...WHICH IS A FAVORABLE ORIENTATION FOR
STRONG WINDS TO OCCUR. GALES ARE EXPECTED TO FALL BELOW 34 KT AT
VARIOUS TIMES TONIGHT AND THU MORNING...AND WILL BE REPLACED BY
SOLID SCA FLAGS AS DEEMED NECESSARY. SEAS ARE ANYWHERE FROM 10-19
FEET N OF CAPE CHARLES AND 5-9 FT S OF CAPE CHARLES. THEY SHOULD
STAY ELEVATED THROUGH THU MORNING AND THEN FALL VERY SLOWLY
THROUGH THE REST OF THE WEEK.
AS THE SFC LOW PUSHES EAST OF LONGITUDE 70W LATE THU NIGHT INTO
FRI...THE PRESSURE GRADIENT REMAINS TIGHT AND A SECONDARY SHORTWAVE
FEATURE MOVES SE ACROSS THE WATERS. THIS FEATURE WILL BRING A
REINFORCING SHOT OF COLD AIR INTO THE REGION AND THE SUBSEQUENT CAA
WILL PRODUCE ANOTHER ROUND OF SOLID SCA CONDITIONS (POSSIBLY GALES
OVER COASTAL WATERS) THU NIGHT INTO FRI MORNING. WINDS THEN SHIFT TO
THE N FRI NIGHT AND HIGH PRESSURE BEGINS TO BUILD INTO THE AREA FROM
NW...BRINGING MORE QUIET CONDITIONS TO AREA WATERS THROUGH THE
WEEKEND.
&&
.TIDES/COASTAL FLOODING...
UPDATE...COASTAL FLOOD WARNING HAS BEEN UPDATED TO RUN THROUGH
EARLY FRIDAY OVER ALL COASTAL AREAS NORTH OF VA/NC BORDER, WITH
THE EXCEPTION OF LANCASTER/NORTHUMBERLAND COUNTIES, WHERE SLIGHTLY
LOWER WATER LEVELS NECESSITATES ONLY AN ADVISORY. TIDAL DEPARTURES
ON THE ORDER OF 2.5 TO 4 FT ABOVE NORMAL HAVE LED TO MODERATE
COASTAL FLOODING IMPACTS ALREADY OVER MUCH OF THIS AREA, WITH
ADDITIONAL ANOMALIES EXPECTED TONIGHT AND OVERNIGHT. MDL AND CBOFS
GUIDANCE HAVE BOTH UNDERESTIMATED THIS NORTHERLY SURGE THIS
EVENING, AND HAVE SIDED CLOSE TO/JUST ABV VIMS GUIDANCE FOR THIS
PACKAGE, AS IT APPEARS TO BE THE MOST ACCURATE IN DEPICTING TIDAL
LEVELS OCCURRING RIGHT NOW. THIS GUIDANCE INDICATING ANOTHER TIDE
CYCLE BETWEEN 2.5 TO 4 FT ABOVE NORMAL (HIGHEST ALONG MD EASTERN
SHORE). IF THIS GUIDANCE COMES TO FRUITION...MODERATE TO SEVER
COASTAL FLOODING IMPACTS ARE EXPECTED AT OCEAN CITY INLET, WITH
WIDESPREAD MODERATE COASTAL FLOODING EXPECTED ON WESTERN SHORE OF
CHES BAY SOUTH OF NEW PT COMFORT DURING THE THU MORNING HIGH TIDE.
SEE CFWAKQ FOR SITE SPECIFIC DETAILS.
UNFORTUNATELY, THE SLOW MOVEMENT OF THE SFC LOW WILL KEEP POSITIVE
TIDAL ANOMALIES THROUGH FRIDAY. AND WHILE THE TIDE CYCLE THURSDAY
NIGHT APPEARS TO BE CLOSER TO MINOR, THE HIGHER ASTRONOMICAL TIDE
FOR FRIDAY MORNING COULD APPROACH MODERATE CCOASTAL FLOODING
IMPACTS YET AGAIN. SUBSTANTIAL IMPROVEMENT IS EXPECTED LATER
FRIDAY AND ESPECIALLY ON SATURDAY.
&&
.AKQ WATCHES/WARNINGS/ADVISORIES...
MD...COASTAL FLOOD WARNING UNTIL 7 AM EST FRIDAY FOR MDZ024-025.
NC...WIND ADVISORY UNTIL 9 AM EST THIS MORNING FOR NCZ017-102.
VA...COASTAL FLOOD WARNING UNTIL 7 AM EST FRIDAY FOR VAZ084>086-091-
094>096-098>100.
WIND ADVISORY UNTIL 9 AM EST THIS MORNING FOR VAZ095-098.
COASTAL FLOOD ADVISORY UNTIL 7 AM EST FRIDAY FOR VAZ077-078.
MARINE...STORM WARNING UNTIL 2 AM EST EARLY THIS MORNING FOR ANZ652-654-
656.
STORM WARNING UNTIL 5 AM EST EARLY THIS MORNING FOR ANZ650.
GALE WARNING UNTIL 7 AM EST FRIDAY FOR ANZ658.
SMALL CRAFT ADVISORY UNTIL 7 AM EST THIS MORNING FOR
ANZ635>637.
GALE WARNING UNTIL 7 AM EST THIS MORNING FOR ANZ630>634-638.
&&
$$
SYNOPSIS...MPR
NEAR TERM...MPR
SHORT TERM...ALB
LONG TERM...BMD
AVIATION...DAP/LSA
MARINE...BMD/MAM
TIDES/COASTAL FLOODING...AKQ
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
625 PM EST FRI MAR 8 2013
.SHORT TERM...(THIS EVENING THROUGH SATURDAY)
ISSUED AT 431 PM EST FRI MAR 8 2013
WATER VAPOR IMAGERY AND RUC ANALYSIS SHOW SPLIT FLOW DOMINATING
NAMERICA. IN THE SRN STREAM...POTENT LOOKING SHORTWAVE HAS MOVED
ONSHORE OVER SRN CA WHILE ANOTHER WAVE IS DROPPING S OVER WRN OR/NRN
CA. BOTH OF THESE WAVES WILL PLAY A ROLE IN THE WX ACROSS THE GREAT
LAKES IN THE COMING DAYS. DOWNSTREAM OF THE WRN TROF...RIDGING IS
OVER THE CNTRL CONUS. TO THE N...ONE SHORTWAVE IS TRACKING THRU NRN
ONTARIO. ANOTHER WAVE IS DROPPING SE INTO ALBERTA ON THE PERIPHERY
OF POLAR VORTEX CENTERED JUST N OF HUDSON BAY. THIS WAVE WILL ALSO
PLAY A ROLE IN THE WX OVER THE GREAT LAKES IN THE COMING DAYS.
CLOSER TO HOME...LOW CLOUDS HAVE LINGERED OVER THE ERN FCST AREA IN
SRLY FLOW OFF LAKE MI. HOWEVER...RECENTLY...ONLY A SMALL AREA OF
STRATOCU REMAINS...STREAMING ONSHORE IN SRN SCHOOLCRAFT COUNTY.
ELSEWHERE...EARLY MARCH SUNSHINE IS DOING ITS JOB ON THE LOWER
ALBEDO FORESTED LAND OF THE U.P. TEMPS HAVE PUSHED INTO THE 40S AT A
NUMBER OF OBS SITES OVER WRN UPPER MI.
IN THE SHORT TERM...QUIET WX TONIGHT WILL GIVE WAY TO INCREASING
PCPN CHANCES SAT UNDER STRENGTHENING WAA REGIME AHEAD OF NRN STREAM
WAVE THAT WILL BE MOVING INTO SRN MANITOBA/ND AND SRN STREAM WAVE
EMERGING OVER THE SRN HIGH PLAINS. TONIGHT...SRLY FLOW WILL BE ON
THE INCREASE AHEAD OF THE AFOREMENTIONED SHORTWAVES. THERE IS THE
USUAL CONCERN UNDER SRLY FLOW THAT LOW CLOUDS MAY DEVELOP. IN THIS
CASE...HOWEVER...THE NAM AND GFS SHOW DRY AIR ADVECTION TONIGHT AT
THE LOW-LEVELS AS TRAJECTORIES STILL HAVE SUFFICIENT COMPONENT
EMANATING FROM RETREATING HIGH PRES. SO...LOW CLOUDS MAY NOT REALLY
BE AN ISSUE TONIGHT. IF ANY VERY LOW/SHALLOW STRATUS DOES DEVELOP...
IT SHOULD ONLY BE IN THE AREAS WITH BEST UPSLOPING OVER CNTRL UPPER
MI. OTHERWISE...EXPECT GENERALLY PARTLY CLOUDY SKIES IN THE
EVENING...AND THEN AN INCREASE IN HIGH CLOUDS OVERNIGHT. TYPICAL FOR
THIS TYPE OF INITIALLY RATHER WEAK SRLY FLOW...EXPECT LOWEST MINS
NEAR THE BAY OF GREEN BAY AS ICE COVER ENHANCES COOLING AND
STRENGTHENS NOCTURNAL INVERSION IN THAT AREA. LOWS SHOULD BE AROUND
20F THERE.
ON SAT...UNDER STRONG WAA AND ISENTROPIC ASCENT (295K SFC)...EXPECT
PCPN TO DEVELOP FROM W TO E AS LOW-LEVEL DRY AIR IS EVENTUALLY
OVERCOME. TRAJECTORIES SUGGEST THERE WILL BE SOME MAINTENANCE
OF THE LOW-LEVEL DRY AIR OVER THE E EVEN AS FORCING AND RESULTING
PCPN ALOFT OVERSPREAD THAT AREA. SO...POPS WILL SHOW A GRADIENT FROM
CATEGORICAL W TO JUST CHC E LATE. IT`S QUITE POSSIBLE THE E MAY
NOT SEE ANY PCPN SAT. AS FOR PTYPE...IT`S A CHALLENGE AS IT ALMOST
ALWAYS IS WHEN IT`S NOT COLD ENOUGH FOR JUST SNOW OR WARM ENOUGH FOR
JUST RAIN. THERE WILL BE THE USUAL BATTLE BETWEEN STRONG WAA AND THE
COOLING IT GENERATES THRU ASCENT AS WELL AS EVAPORATIVE COOLING
EARLY ON. BELIEVE THE EVAPORATIVE COOLING EARLY ON WILL LEAD TO
PREDOMINANTLY SNOW AS THE PTYPE INITIALLY. THEREAFTER...FCST
SOUNDINGS SHOW PROFILE GENERALLY HOVERING AROUND 0C IN THE LOWER
LEVELS...FLUCTUATING BASED ON ASCENT/PCPN INTENSITY. MEANWHILE...THE
NEAR SFC LAYER MAY RESPOND A LITTLE TO DAYTIME HEATING...PUSHING THE
ODDS TOWARD RAIN. AT THIS POINT...WILL INCLUDE SNOW AS THE GENERAL
PREVAILING PTYPE IN MOST AREAS WITH A MENTION OF RAIN. INCLUDED FZRA
AS WELL WHERE TEMPS ARE AROUND FREEZING. IF THERE IS FZRA...IT
SHOULD BE CONFINED TO THE MORNING/EARLY AFTN BEFORE SURFACES RESPOND
TO WEAK DAYTIME HEATING. WITH TEMPS PUSHING INTO THE MID 30S...
WET/SLUSHY SNOW ACCUMULATIONS WILL BE MINOR...MAYBE AROUND AN INCH.
.LONG TERM...(SATURDAY NIGHT THROUGH FRIDAY)
ISSUED AT 431 PM EST FRI MAR 8 2013
SATURDAY NIGHT...
THE MODELS HAVE COME INTO BETTER AGREEMENT WITH THE EVOLUTION OF THE
SYOPTIC PATTERN WITH A PROGRESSIVE PATTERN AND LITTLE PHASING
BETWEEN THE NRN STREAM MID LEVEL TROUGH MOVING THROUGH NRN ONTARIO
AND THE NRN GREATLAKES AND THE SRN STREAM SHORTWAVE MOVING EAST FROM
THE PLAINS.
ABUNDANT MOISTURE INFLOW WITH MODERATE TO STRONG 285K-300K
ISENTROPIC LIFT AND A PERIOD OF 700-600 MB FGEN SHOULD SUPPORT A
BAND OF PCPN THROUGH THE CWA...ESPECIALLY BTWN 00Z-06Z WITH QPF
AMOUNTS TO AROUND 0.25 INCH. CONFIDENCE IS ALSO HIGHER THAT A
SIGNIFCANT (1C TO 3C) WARM LAYER WILL SPREAD THROUGH MOST OF THE CWA
GIVEN STRONG WAA WITH SW 40-45 KT 850 MB WINDS BY 00Z/SUN. GENERALLY
UTILIZED NAM/GEM LOW LEVEL THERMAL PROFILE TO DELINEATE PCPN TYPE
PATTERN. WITH ENOUGH WARMTH LINGERING FROM DAYTIME HEATING...ANY SFC
COLD LAYER WILL BE LESS PRONOUNCED LIMITING POTENTIAL FOR FZRA.
SO...MAINLY RA/SN MIX EXPECTED WITH THE GREATEST SNOW CHANCES OVER
THE WEST HALF. WITH LOW SLR AOB 10/1...ANY WET SNOWFALL AMOUNTS
SHOULD ONLY AMOUNT TO AN INCH OR TWO AT MOST.
SUNDAY...THERE WERE GREATER MODEL DIFFERENCES AS THE GFS ALLOWS
ANOTHER DEFORMATION BAND OF PCPN TO LIFT INTO UPPER ASSOCIATED WITH
THE SRN STREAM SHRTWV. SINCE THE GLOBAL GEM/ECMWF CONTINUE TO SHOW A
MORE PROGRESSIVE SOLUTION...THE FCST CONTINUES WITH THE IDEA OF
TAPERING OFF POPS/QPF FROM WEST TO EAST WITH MAINLY JUST CHANCE POPS
BY AFTERNOON. SOME LAKE ENHANCED SNOW MAY DEVELOP BUT WITH THE
SYNOPTIC SCALE UPWARD MOTION AND DEEPER MOISTURE DEPARTING...ANY
AMOUNTS SHOULD BE LIGHT.
SUN NIGHT INTO MON...850 MB TEMPS DROPPING INTO THE -12C TO -14C
ALONG WITH CONTINUED CYCLONIC NRLY FLOW COULD STILL SUPPORT SOME
LES. HOWEVER...WITH STRONG 850-700 MB DRYING...ANY AMOUNTS
ARE EXPECTED TO BE LIGHT
TUE-FRI...MDLS WERE CONSISTENT WITH A WEAK CLIPPER SHORTWAVE AND SFC
TROUGH MOVING THROUGH THE UPPER GREAT LAKES MON NIGHT INTO TUE. THE FAVORED
ECMWF REMAINED MORE AMPLIFIED WITH THE ERN GREAT LAKES TROUGH BY WED
WITH COLDER AIR AVAILABLE FOR SOME NW FLOW LES COMPARED TO THE THE
GFS. CONFIDENCE IN DETAILS DROPS OFF BY THU-FRI WITH REGARD TO THE
POSITION/STRENGTH OF THE NEXT SHORTWAVE THAT COULD BRING SNOW CHANCES
INTO THE REGION. TEMPS SHOULD REMAIN AT OR BELOW SEASONAL AVERAGES.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z SATURDAY EVENING)
ISSUED AT 622 PM EST FRI MAR 8 2013
EXPECT VFR CONDITIONS TO PREVAIL THRU TNGT WITH S WIND ON THE WRN
FLANK OF HI PRES IN LOWER MI AND DRYNESS OF UPSTREAM AIRMASS TO THE S.
THE ONLY EXCEPTION MIGHT BE AT SAW WITH AN UPSLOPE FLOW DOWNSTREAM OF
AN AREA OVER SCENTRAL UPR MI WHERE RADIATIONAL COOLING MIGHT BE
ENHANCED ENUF TO RESULT IN SOME LO CLDS/FOG. MAINTAINED MENTION OF
SCT LO CLDS TO REFLECT THIS POTENTIAL THAT WOULD LINGER JUST PAST
SUNRISE ON SAT. THEN AN APRCHG LO PRES TROF WL BRING AN INCRSG THREAT
OF SOME SN OR MIXED RA/SN DURING THE LATE MRNG/AFTN ON SAT. LINGERING
LLVL DRYNESS WL SLOW DOWN THE ONSET OF LOWER CIGS/VSBY...BUT THESE
CONDITIONS SHOULD DVLP WITH PERSISTENT PCPN/MOISTENING. THE BEST SHOT
AT IFR WX WL BE AT CMX...FARTHER FM DEPARTING LLVL DRY AIR AND WHERE
NEAR SFC SE FLOW WL UPSLOPE.
&&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 431 PM EST FRI MAR 8 2013
SOUTHERLY FLOW WILL DOMINATE TONIGHT THRU SAT EVENING AHEAD OF AN
APPROACHING LOW PRES TROF. TYPICAL FOR SOUTHERLY FLOW...STRONGEST
WINDS WILL BE OVER ERN LAKE SUPERIOR...REACHING UPWARDS OF 30KT SAT
AFTN/EVENING. TROF WILL THEN PASS ACROSS LAKE SUPERIOR LATE SAT
NIGHT/SUN...BRINGING A SHIFT TO 20-30KT NW WINDS. WINDS WILL THEN
SLOWLY SUBSIDE LATE SUN NIGHT/MON...FALLING TO UNDER 15KT FOR MON
NIGHT/TUE. MAY SEE A SLIGHT INCREASE IN WINDS WED.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...ROLFSON
LONG TERM...JLB
AVIATION...KC
MARINE...JLB
AREA FORECAST DISCUSSION
NWS GRAND RAPIDS MI
1235 PM EST THU MAR 7 2013
.SYNOPSIS...
ISSUED AT 328 AM EST THU MAR 7 2013
LAKE SHORE AREAS WILL SEE OCCASIONAL FLURRIES OR LIGHT SNOW
TODAY...OTHERWISE IT WILL BE PARTLY TO MOSTLY CLOUDY WITH
TEMPERATURES IN THE 30S. DRY WEATHER IS EXPECTED FOR FRIDAY AND
MUCH OF SATURDAY. TEMPERATURES WILL WARM TO AROUND 40 ON FRIDAY AND
INTO THE 40S FOR SATURDAY.
A RATHER UNSETTLED PERIOD IS EXPECTED LATE IN THE WEEKEND AND INTO
EARLY NEXT WEEK. RAIN IS EXPECTED BY LATE SATURDAY OR SATURDAY
NIGHT AND CONTINUING INTO SUNDAY. THE PRECIPITATION MAY CHANGE TO
SNOW...OR A MIX OF RAIN AND SNOW SUNDAY NIGHT THROUGH MONDAY
NIGHT...AS TEMPERATURES COOL FOR NEXT WEEK.
&&
.UPDATE...
ISSUED AT 1046 AM EST THU MAR 7 2013
I DECREASED CLOUD COVER FOR THE REMAINDER OF THE DAY. MANY OF THE
CLOUDS THAT WERE AROUND THIS MORNING HAVE CONTINUED TO ERODE AND
EXIT TO EAST. CLEARING WILL CONTINUE FROM WEST TO EAST THIS
AFTERNOON AND THIS IS SHOWN BY THE NAM AND RAP MODEL SUGGESTIONS.
&&
.SHORT TERM...(TODAY THROUGH SATURDAY)
ISSUED AT 328 AM EST THU MAR 7 2013
A SMALL AREA OF LAKE EFFECT SNOW SHOWERS/FLURRIES WAS CLIPPING
WESTERN VAN BUREN COUNTY THIS MORNING. EXPECT THIS MAY LINGER MUCH
OF TODAY AS COLD ADVECTION PEAKS AROUND MID DAY. THE FLOW REMAINS
330-350 SO ONLY THE LAKE SHORE WILL EXPERIENCE OCCASIONAL FLURRIES
OR LIGHT SNOW. IT COULD RESULT IN A LIGHT DUSTING IN SOME LOCALES.
INLAND AREAS SHOULD SEE A MIX OF CLOUDS AND SUN...WITH THE CLOUDS
MORE FREQUENT THAN SUN. SLIGHTLY COOLER THAN YESTERDAY WITH MOSTLY
LOW AND MID 30S FOR HIGHS.
UPPER RIDGING MOVES FOR THE END OF THE WORK WEEK. ALONG WITH THIS
WILL COME WARM ADVECTION. ANY LAKE SNOW SHOULD END BY THIS EVENING
ON THE HEELS OF THE WARM ADVECTION. SKIES SHOULD GRADUALLY CLEAR
LEADING TO A MOSTLY SUNNY FRIDAY WITH TEMPS APPROACHING 40.
CLOUDS SHOULD THICKEN THROUGH SATURDAY WITH WARM ADVECTION CLOUDS
AND AN INCREASING GULF MOISTURE FLOW. THE WARM FETCH WILL PUSH
TEMPS WELL INTO THE 40S. WE MAY SEE A FEW RAIN SHOWERS TOWARD
SATURDAY EVENING AS THE LOW LEVELS MOISTEN AHEAD OF A SYSTEM
DEVELOPING OVER THE CENTRAL PLAINS.
.LONG TERM...(SATURDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 328 AM EST THU MAR 7 2013
SCATTERED TO NUMEROUS RAIN SHOWERS ARE EXPECTED SATURDAY NIGHT AND
SUNDAY AS A WARM AIR ADVECTION PATTERN IMPACTS THE REGION. 40 TO 50
KT SOUTHERLY LOW LEVEL JET IS PROGGED OUT AHEAD OF AN APPROACHING
FRONTAL BOUNDARY... WITH NARROW CORRIDOR OF PWATS AROUND ONE INCH
STREAMING NORTH. WILL NOT INCLUDE THUNDER AT THIS POINT... BUT WILL
HAVE TO WATCH FOR THAT POSSIBILITY. MODELS ARE STILL STRUGGLING WITH
TIMING/STRENGTH OF JET STREAK ENERGY EJECTING NORTHEAST FROM THE
FOUR CORNERS REGION... BUT IT DOES LIKE A STRONG SHORTWAVE WILL BE
MOVING INTO IOWA AROUND 12Z SUNDAY.
CURRENT MODEL SOLUTIONS IMPLY THAT THE SHORTWAVE MOVING NEWD FROM
THE CENTRAL PLAINS REGION ON SUNDAY WILL WEAKEN AND SHEAR OUT AS IT
COMES INTO MI AND GETS ABSORBED IN WITH AN APPROACHING NRN STREAM
TROUGH. THE SFC FRONTAL BOUNDARY ALSO WEAKENS BUT DOES SLIP THROUGH
THE ENTIRE CWFA BY 12Z MONDAY. MODELS HAVE BEEN VERY INCONSISTENT IN
REGARDS TO WHAT HAPPENS AFTER THAT... BUT CONTINUE TO SUGGEST THE
POSSIBILITY OF ANOTHER WAVE MOVING MOVING NORTHEAST ALONG THE SFC
FRONT EARLY NEXT WEEK. PRECIP TYPE REMAINS PROBLEMATIC... SINCE
IF THE FRONT GETS HUNG UP THEN THE LOW LEVEL COLD AIR MAY HAVE A
TOUGH TIME FILTERING INTO THE REGION FROM THE NORTH.
DESPITE THE MODEL INCONSISTENCIES FOR EARLY NEXT WEEK... ALL
SOLUTIONS SEEM TO EVENTUALLY CONVERGE ON A RATHER CHILLY PATTERN BY
MID WEEK WITH TROUGHING AND COLD AIR ALOFT. THIS WOULD LEAD TO
SCATTERED SNOW OR MIXED RAIN AND SNOW SHOWERS AND HIGHS IN THE 30S.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z FRIDAY AFTERNOON)
ISSUED AT 1235 PM EST THU MAR 7 2013
CONFIDENCE IS HIGH THAT VFR CONDITIONS WILL PREVAIL THROUGH THIS
EVENING. CEILINGS IN THE 3000-4000 FT AGL RANGE SHOULD SLOWLY RISE
THIS AFTERNOON AND MAY EVEN SLOWLY DISSIPATE FROM NORTHWEST TO
SOUTHEAST DURING THIS TIME. THE EASTERNMOST TERMINALS (KLAN AND
KJXN) HAVE THE BEST CHANCE OF HOLDING ON TO CEILINGS FOR MOST OF THE
DAY.
ALTHOUGH NOT ADVERTISED SPECIFICALLY IN THE TAFS...A LOSS OF CEILINGS
OVERNIGHT COMBINED WITH LIGHT WINDS WILL MAKE PATCHY FOG POSSIBLE.
IF FOG WERE TO OCCUR AT THE TERMINALS...IT WOULD MOST LIKELY START
AFTER 06Z AND HAVE A GOOD CHANCE OF DROPPING BELOW IFR VISIBILITY
THRESHOLDS OF 3 MILES. THIS WILL BE THE MAIN THING TO WATCH
THROUGH THE NEXT SCHEDULED TAF UPDATE.
&&
.MARINE...
ISSUED AT 328 AM EST THU MAR 7 2013
RATHER LIGHT NW WINDS TODAY WILL KEEP WAVES ON THE LOWER SIDE.
WINDS REMAIN LIGHT THROUGH MUCH OF THE SHORT TERM. HOWEVER WINDS
AND WAVES SHOULD INCREASE BY SATURDAY AFTERNOON AS THE NEXT SYSTEM
APPROACHES.
&&
.HYDROLOGY...
ISSUED AT 328 AM EST THU MAR 7 2013
A GRADUAL THAW WILL CONTINUE WITH ABOVE FREEZING DAYTIME TEMPS AND
DROPPING BELOW FREEZING AT NIGHT. WARMER CONDITIONS ARRIVE OVER THE
WEEKEND ALONG WITH SOME RAIN. THIS COMBINATION WILL BE MONITORED
FOR POSSIBLE HYDRO IMPACTS.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LM...NONE.
&&
$$
UPDATE...JAM WDM
SYNOPSIS...JK
SHORT TERM...JK
LONG TERM...MEADE
AVIATION...TJT
HYDROLOGY...JK
MARINE...JK
AREA FORECAST DISCUSSION
NWS GRAND RAPIDS MI
1048 AM EST THU MAR 7 2013
.SYNOPSIS...
ISSUED AT 328 AM EST THU MAR 7 2013
LAKE SHORE AREAS WILL SEE OCCASIONAL FLURRIES OR LIGHT SNOW
TODAY...OTHERWISE IT WILL BE PARTLY TO MOSTLY CLOUDY WITH
TEMPERATURES IN THE 30S. DRY WEATHER IS EXPECTED FOR FRIDAY AND
MUCH OF SATURDAY. TEMPERATURES WILL WARM TO AROUND 40 ON FRIDAY AND
INTO THE 40S FOR SATURDAY.
A RATHER UNSETTLED PERIOD IS EXPECTED LATE IN THE WEEKEND AND INTO
EARLY NEXT WEEK. RAIN IS EXPECTED BY LATE SATURDAY OR SATURDAY
NIGHT AND CONTINUING INTO SUNDAY. THE PRECIPITATION MAY CHANGE TO
SNOW...OR A MIX OF RAIN AND SNOW SUNDAY NIGHT THROUGH MONDAY
NIGHT...AS TEMPERATURES COOL FOR NEXT WEEK.
&&
.UPDATE...
ISSUED AT 1046 AM EST THU MAR 7 2013
I DECREASED CLOUD COVER FOR THE REMAINDER OF THE DAY. MANY OF THE
CLOUDS THAT WERE AROUND THIS MORNING HAVE CONTINUED TO ERODE AND
EXIT TO EAST. CLEARING WILL CONTINUE FROM WEST TO EAST THIS
AFTERNOON AND THIS IS SHOWN BY THE NAM AND RAP MODEL SUGGESTIONS.
&&
.SHORT TERM...(TODAY THROUGH SATURDAY)
ISSUED AT 328 AM EST THU MAR 7 2013
A SMALL AREA OF LAKE EFFECT SNOW SHOWERS/FLURRIES WAS CLIPPING
WESTERN VAN BUREN COUNTY THIS MORNING. EXPECT THIS MAY LINGER MUCH
OF TODAY AS COLD ADVECTION PEAKS AROUND MID DAY. THE FLOW REMAINS
330-350 SO ONLY THE LAKE SHORE WILL EXPERIENCE OCCASIONAL FLURRIES
OR LIGHT SNOW. IT COULD RESULT IN A LIGHT DUSTING IN SOME LOCALES.
INLAND AREAS SHOULD SEE A MIX OF CLOUDS AND SUN...WITH THE CLOUDS
MORE FREQUENT THAN SUN. SLIGHTLY COOLER THAN YESTERDAY WITH MOSTLY
LOW AND MID 30S FOR HIGHS.
UPPER RIDGING MOVES FOR THE END OF THE WORK WEEK. ALONG WITH THIS
WILL COME WARM ADVECTION. ANY LAKE SNOW SHOULD END BY THIS EVENING
ON THE HEELS OF THE WARM ADVECTION. SKIES SHOULD GRADUALLY CLEAR
LEADING TO A MOSTLY SUNNY FRIDAY WITH TEMPS APPROACHING 40.
CLOUDS SHOULD THICKEN THROUGH SATURDAY WITH WARM ADVECTION CLOUDS
AND AN INCREASING GULF MOISTURE FLOW. THE WARM FETCH WILL PUSH
TEMPS WELL INTO THE 40S. WE MAY SEE A FEW RAIN SHOWERS TOWARD
SATURDAY EVENING AS THE LOW LEVELS MOISTEN AHEAD OF A SYSTEM
DEVELOPING OVER THE CENTRAL PLAINS.
.LONG TERM...(SATURDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 328 AM EST THU MAR 7 2013
SCATTERED TO NUMEROUS RAIN SHOWERS ARE EXPECTED SATURDAY NIGHT AND
SUNDAY AS A WARM AIR ADVECTION PATTERN IMPACTS THE REGION. 40 TO 50
KT SOUTHERLY LOW LEVEL JET IS PROGGED OUT AHEAD OF AN APPROACHING
FRONTAL BOUNDARY... WITH NARROW CORRIDOR OF PWATS AROUND ONE INCH
STREAMING NORTH. WILL NOT INCLUDE THUNDER AT THIS POINT... BUT WILL
HAVE TO WATCH FOR THAT POSSIBILITY. MODELS ARE STILL STRUGGLING WITH
TIMING/STRENGTH OF JET STREAK ENERGY EJECTING NORTHEAST FROM THE
FOUR CORNERS REGION... BUT IT DOES LIKE A STRONG SHORTWAVE WILL BE
MOVING INTO IOWA AROUND 12Z SUNDAY.
CURRENT MODEL SOLUTIONS IMPLY THAT THE SHORTWAVE MOVING NEWD FROM
THE CENTRAL PLAINS REGION ON SUNDAY WILL WEAKEN AND SHEAR OUT AS IT
COMES INTO MI AND GETS ABSORBED IN WITH AN APPROACHING NRN STREAM
TROUGH. THE SFC FRONTAL BOUNDARY ALSO WEAKENS BUT DOES SLIP THROUGH
THE ENTIRE CWFA BY 12Z MONDAY. MODELS HAVE BEEN VERY INCONSISTENT IN
REGARDS TO WHAT HAPPENS AFTER THAT... BUT CONTINUE TO SUGGEST THE
POSSIBILITY OF ANOTHER WAVE MOVING MOVING NORTHEAST ALONG THE SFC
FRONT EARLY NEXT WEEK. PRECIP TYPE REMAINS PROBLEMATIC... SINCE
IF THE FRONT GETS HUNG UP THEN THE LOW LEVEL COLD AIR MAY HAVE A
TOUGH TIME FILTERING INTO THE REGION FROM THE NORTH.
DESPITE THE MODEL INCONSISTENCIES FOR EARLY NEXT WEEK... ALL
SOLUTIONS SEEM TO EVENTUALLY CONVERGE ON A RATHER CHILLY PATTERN BY
MID WEEK WITH TROUGHING AND COLD AIR ALOFT. THIS WOULD LEAD TO
SCATTERED SNOW OR MIXED RAIN AND SNOW SHOWERS AND HIGHS IN THE 30S.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z FRIDAY MORNING)
ISSUED AT 655 AM EST THU MAR 7 2013
MVFR CIGS WERE IMPACTING MUCH OF THE AREA THIS MORNING... BUT
CONDITIONS SHOULD TREND TOWARD MOSTLY VFR BY NOON AS HIGH
PRESSURE OVER WISCONSIN MOVES EAST.
THERE HAS BEEN AREAS OF IFR/LIFR FOG ASSOCIATED WITH THE SFC HIGH
PRESSURE RIDGE CURRENTLY TO OUR WEST. THAT MAY BE A CONCERN ACROSS
MICHIGAN LATE TONIGHT SINCE THE RIDGE WILL BE OVERHEAD. HOWEVER AT
THIS POINT OPTED TO LEAVE IT OUT OF THE TAFS AS CONFIDENCE IN FOG
DEVELOPMENT IS LOW AND IT IS DEPENDENT ON CLEARING OF THE CURRENT
CLOUD COVER.
&&
.MARINE...
ISSUED AT 328 AM EST THU MAR 7 2013
RATHER LIGHT NW WINDS TODAY WILL KEEP WAVES ON THE LOWER SIDE.
WINDS REMAIN LIGHT THROUGH MUCH OF THE SHORT TERM. HOWEVER WINDS
AND WAVES SHOULD INCREASE BY SATURDAY AFTERNOON AS THE NEXT SYSTEM
APPROACHES.
&&
.HYDROLOGY...
ISSUED AT 328 AM EST THU MAR 7 2013
A GRADUAL THAW WILL CONTINUE WITH ABOVE FREEZING DAYTIME TEMPS AND
DROPPING BELOW FREEZING AT NIGHT. WARMER CONDITIONS ARRIVE OVER THE
WEEKEND ALONG WITH SOME RAIN. THIS COMBINATION WILL BE MONITORED
FOR POSSIBLE HYDRO IMPACTS.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LM...NONE.
&&
$$
UPDATE...JAM WDM
SYNOPSIS...JK
SHORT TERM...JK
LONG TERM...MEADE
AVIATION...MEADE
HYDROLOGY...JK
MARINE...JK
AREA FORECAST DISCUSSION
NWS HASTINGS NE
1126 PM CST WED MAR 6 2013
.SHORT TERM...(TONIGHT THROUGH THURSDAY)
ISSUED AT 353 PM CST WED MAR 6 2013
BIGGEST CHALLENGE WILL BE DETERMINING SKY COVER AND VISIBILITY FOR
TONIGHT INTO EARLY THURSDAY MORNING.
THE STRATUS THAT STUCK AROUND AND RETROGRADED WESTWARD INTO THE
EASTERN HALF OF THE CWA HAS LONG MIXED OUT...WITH ONLY SOME CIRRUS
MAKING ITS WAY INTO OUR CWA FROM THE SOUTH/SOUTHWEST.
SATELLITE AND WATER VAPOR REVEAL SPLIT FLOW IN UPPER
LEVELS...PLACING OUR CWA BETWEEN. THE SURFACE RIDGE CONTINUES TO
TREK EAST...WHICH WILL EVENTUALLY TURN WIND TO A MORE SE TO S/SE
WIND DIRECTION. MODELS ARE STILL KEYING IN ON SOME POSSIBLE
STRATUS/FOG IN THE WESTERN CWA OVERNIGHT AND INTO THURSDAY
MORNING...AND WITH THIS CONSISTENT SIGNAL...HAVE LEFT IN THE FOG
FROM THE PREVIOUS FORECAST AND EXPANDED THIS A LITTLE FARTHER TO THE
WEST. THE RAP IS PICKING UP SOME INCREASED STRATUS IN THE WEST AND
EVENTUALLY NORTH AS A LOW-LEVEL JET INCREASED DURING THE OVERNIGHT.
THE NMM ALSO INDICATES SOME INCREASE STRATUS OVERNIGHT...BUT OVER A
LARGER PORTION OF THE CWA. CONFIDENCE REMAINS LOW FOR SKY COVER
TONIGHT AS MODELS DO NOT HAVE A GREAT HANDLE ON LOW-LEVEL SKY COVER
AND FRANKLY...HAVE NOT DONE THAT GREAT FOR AWHILE. THE NAM
ADVERTISES SOME LIGHT QPF IN THE NORTHERN CWA...SOMEWHAT NEAR THE
NOSE OF THE MODEST LOW-LEVEL JET DEVELOPING TONIGHT. WITH SUCH A DRY
PROFILE...I DOUBT IF THERE IS MUCH CHANCE AT ALL OF MEASURABLE
PRECIPITATION...ALTHOUGH THIS COULD BE AN INDICATOR OF SOME
DEVELOPING STRATUS...WHICH SEEMS TO BE SUPPORTED BY THE
USING RECENT VERIFICATION STATISTICS...I MADE SOME MINOR CHANGES
TO TEMPERATURES FOR TONIGHT AND THURSDAY...WITH THE REMAINING
SNOWPACK IN THE WESTERN CWA STILL HAVING SOME INFLUENCE WITH HIGH
TEMPERATURES THURSDAY. THIS SNOWPACK MAY HAVE LIMITED EFFECT ON THE
VISIBILITY FOR OVERNIGHT TONIGHT INTO THURSDAY MORNING AS WELL.
.LONG TERM...(THURSDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 353 PM CST WED MAR 6 2013
MAIN FORECAST CONCERNS ARE PRECIPITATION FRIDAY NIGHT THROUGH SUNDAY
NIGHT AND TEMPERATURES THROUGH THE PERIOD.
AN UPPER LEVEL RIDGE WILL MOVE THROUGH THE AREA THURSDAY NIGHT INTO
FRIDAY. THERE IS WARM ADVECTION ACROSS THE AREA AND TEMPERATURES
SHOULD BE WARMER. IN ADDITION...THE SOUTH WINDS INCREASE THE
MOISTURE ACROSS THE AREA AND CLOUDS WILL INCREASE. A COUPLE OF THE
MODELS HAVE STARTED SHOWING SOME LIGHT QPF ASSOCIATED WITH THE WARM
ADVECTION. HAVE KEPT THE FORECAST DRY FOR NOW AND WILL WAIT FOR
FURTHER RUNS.
BY FRIDAY NIGHT AN UPPER LEVEL LOW PRESSURE SYSTEM MOVING OUT OF THE
ROCKIES WILL START TO AFFECT THE AREA. PRECIPITATION SPREADS ACROSS
THE AREA. WARM TEMPERATURES WILL KEEP PRECIPITATION IN THE FORM OF
RAIN. THERE IS SOME WEAK INSTABILITY WITH MUCAPE UP TO 500 J/KG
ACROSS THE AREA. THERE COULD BE SOME ISOLATED THUNDERSTORMS FRIDAY
NIGHT INTO SATURDAY. SATURDAY WILL CONTINUE TO BE WARM AHEAD OF THE
SURFACE LOW WITH SOUTHERLY WINDS.
THE MODELS HAVE COME INTO BETTER AGREEMENT WITH THE TRACK OF THE
UPPER LOW AS IT MOVES THROUGH THE PLAINS. AS THE UPPER LOW MOVES
THROUGH THE PLAINS THE COLDER AIR MOVES INTO THE AREA FROM THE WEST.
SATURDAY NIGHT THE PRECIPITATION CHANGES FROM RAIN TO SNOW IN THE
WEST DURING THE EVENING THEN THE SNOW SPREADS ACROSS THE AREA DURING
NIGHT. BY MORNING EXPECT SNOW IN THE NORTHWEST WITH RAIN AND SNOW
FURTHER SOUTHEAST. ON SUNDAY SNOW WILL BE FOUND ACROSS MUCH OF THE
AREA WITH SOME RAIN OR SNOW POSSIBLE IN THE SOUTHEAST. THE UPPER LOW
WILL SLIDE TO THE EAST SUNDAY NIGHT AND PRECIPITATION WILL COME TO
AN END. PRECIPITATION AMOUNTS ARE NOT VERY HIGH AND EXPECT SOME SNOW
ACCUMULATIONS. SUNDAY WILL BE COLDER WITH HIGHS ONLY IN THE 30S
BEHIND THE COLD FRONT.
THE UPPER LOW WILL BE TO THE EAST AND THERE WILL BE NORTHWEST FLOW
ACROSS THE AREA MONDAY THROUGH WEDNESDAY. THERE COULD BE SOME CLOUDS
AS A FEW WEAK UPPER LEVEL WAVES MOVE THROUGH THE AREA...BUT THERE IS
WARM ADVECTION AND TEMPERATURES SHOULD START TO WARM UP. DEPENDING
ON HOW MUCH SNOW THERE IS SATURDAY NIGHT INTO SUNDAY THE
TEMPERATURES MAY REMAIN A LITTLE COOLER FOR MONDAY...BUT WARM FOR
TUESDAY AND WEDNESDAY.
&&
.AVIATION...(FOR THE 06Z TAF THROUGH 06Z THURSDAY NIGHT)
ISSUED AT 1126 PM CST WED MAR 6 2013
VFR CONDITIONS ARE CURRENTLY FORECAST FOR THE TAF TONIGHT. MODELS ARE
VERY INCONSISTENT WITH THE POSSIBILITY OF LOW STRATUS CEILINGS AND
LLWS OVERNIGHT. HAVE HIGHER CONFIDENCE WITH LLWS SETTING UP THAN
THE POSSIBILITY OF STRATUS...WILL CONTINUE TO MONITOR FOR STATUS
SETTING UP LATER TONIGHT. VISIBILITIES SHOULD REMAIN VFR
OVERNIGHT AS THE SURFACE WINDS WILL BE AROUND 10KTS.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
KS...NONE.
&&
$$
SHORT TERM...HEINLEIN
LONG TERM...JCB
AVIATION...BEDA/BRYANT
AREA FORECAST DISCUSSION
NWS BURLINGTON VT
634 PM EST FRI MAR 8 2013
.SYNOPSIS...
SURFACE HIGH PRESSURE ACROSS THE CENTRAL GREAT LAKES WILL SHIFT INTO
THE NORTHEAST OVER THE WEEKEND. THIS WILL RESULT IN MOSTLY CLEAR
SKIES AND MUCH ABOVE NORMAL TEMPERATURES...ESPECIALLY HIGHS ON
SUNDAY. THE NEXT CHANCE FOR PRECIPITATION MAINLY IN THE FORM OF RAIN
SHOWERS WILL BE LATE MONDAY INTO TUESDAY. A SLOW COOLING TREND WILL
DEVELOP TOWARD THE MIDDLE OF NEXT WEEK.
&&
.NEAR TERM /UNTIL 6 AM SATURDAY MORNING/...
AS OF 623 PM EST FRIDAY...MINOR ADJUSTMENTS AS OF EARLY EVENING
MAINLY TO TWEAK SKY COVER SLIGHTLY...AND BLEND CURRENT T/TD
OBSERVATIONAL DATA AHEAD TO THE MIDNIGHT HOUR OR SO. CURRENT
READINGS ARE RUNNING SOMEWHAT ABOVE PRIOR INDICATIONS...MAINLY DUE
TO CONTINUED WIND/MIXED PBL AND IF LATEST RAP 2M TEMP DATA IS ANY
INDICATION...WE MAY END UP A TAD MILDER OVERNIGHT. NO WHOLESALE
CHANGES IN THAT REGARD AT THIS POINT AS I WANT TO SEE HOW THINGS
TREND OVER THE NEXT FEW HOURS. REST OF FCST REMAINS LARGELY
UNCHANGED. HAVE A GREAT EVENING. PRIOR DISCUSSION FOLLOWS...
TONIGHT...MID/UPPER LVL RIDGE AND ASSOCIATED SFC HIGH PRES WL
SLOWLY MOVE FROM THE CENTRAL GREAT LAKES INTO THE NE CONUS. THIS
WL RESULT IN CLRING SKIES AND LIGHTER WINDS. RAP/GFS AND NAM
SOUNDINGS SHOW PLENTY OF LLVL RH SFC SFC THRU 875MB
TONIGHT...ESPECIALLY AT SLK...BUT BL WINDS REMAIN BTWN 6-10 KNTS.
GIVEN GOOD RADIATIONAL COOLING...EXPECT SFC TEMPS TO REACH SFC
DWPT TEMPS IN DEEPER/SHELTERED VALLEYS...WITH AREAS OF LOW
CLOUDS/FG POSSIBLE...ESPECIALLY NORTHERN NY NEAR SLK. IN
ADDITION...SOUNDINGS SHOW A SHARP INVERSION DEVELOPING WITH
VALLEYS IN THE SINGLE DIGITS/LWR TEENS. MEANWHILE...MTN TOPS/MID
SLOPES HOLD IN THE 20S TO NEAR 30F. AS SOUNDINGS SHOW A THERMAL
BELT BTWN 2KFT AND 3KFT FEET OF TEMPS ABOVE 0C. CPV/SLV TEMPS WL
RANGE IN THE UPPER TEENS TO LOWER 20S...WITH MAINLY SINGLE
DIGITS/TEENS FOR THE NEK.
&&
.SHORT TERM /6 AM SATURDAY MORNING THROUGH SUNDAY NIGHT/...
AS OF 310 PM EST FRIDAY...BY SATURDAY...MID/UPPER LVL RIDGE MOVES
OVERHEAD AND SOUNDINGS SHOW A DEEP DRY LAYER. THIS WL RESULT IN
PLENTY OF SUNSHINE AND LIGHT WINDS. STILL SOME UNCERTAINTY WITH
REGARDS TO AMOUNT OF MIXING...ESPECIALLY OVER THE SNOWPACK ACRS
THE MTN VALLEYS OF THE DACK AND CENTRAL/EASTERN VT. PROGGED 85H
TEMPS WARM TO 0C BY 18Z SAT...BUT SOUNDINGS SHOW MIXING ONLY TO
975MB...WHERE TEMPS ARE BTWN -1C AND -3C...ESPECIALLY CPV AND
DEEPER VALLEYS. THESE THERMAL PROFILES AND SNOWPACK SUGGEST L/M40S
CPV AND PARTS OF THE SLV/DACKS WITH M/U 30S OVER THE SNOWPACK
VALLEYS OF CENTRAL/EASTERN VT...INCLUDING THE NEK. WOULD NOT BE
SURPRISED IF MID SLOPE LOCATIONS BTWN 1200 AND 2500 FEET WARM INTO
THE MID/UPPER 40S SATURDAY...GIVEN THE SHARP VERTICAL THERMAL
GRADIENT. ANY LOW CLOUDS/BR SHOULD BURN OFF BY 14Z SATURDAY.
MID/UPPER LVL RIDGE THEN SHIFTS INTO EASTERN NEW ENGLAND BY 12Z
SUNDAY AS A WARM SOUTHERLY FLW CONTS ACRS OUR CWA. TEMPS WL BE
TRICKY SAT NIGHT/SUNDAY MORNING WITH WARM READINGS IN THE 20S/30S
IN THE MTNS AND COLDEST VALUES IN THE TEENS/LWR 20S IN DEEPER
SNOWPACK VALLEYS. THERMAL PROFILES CONT TO SHOW A SHARP INVERSION
ACRS OUR CWA. ON SUNDAY...HAVE NOTICED SE SFC TO 925MB FLW
DEVELOPING ACRS OUR CENTRAL/EASTERN VT ZNS...WHICH MAY HELP TO
ADVECT A LLVL COOL MARITIME AIRMASS INTO OUR FA. THIS WOULD LIMIT
AMOUNT OF WARMING AND COULD KEEP TEMPS IN CENTRAL/EASTERN VT IN
THE U30S TO M40S. MEANWHILE...NAM12 SHOWS 925MB TEMPS ACRS THE SE
DOWNSLOPE REGIONS OF THE DACKS FROM GOUVERNEUR TO CANTON TO
POTSDAM BTWN 8 AND 10C BY 00Z MONDAY...SUPPORTING HIGHS WELL INTO
THE 50S TO NEAR 60F. PROGGED 925MB TEMPS ACRS EASTERN/CENTRAL
VT...EAST OF THE GREENS ARE ONLY BTWN 2 AND 4C...WITH LIMITED
MIXING...SUPPORTING MUCH COOLER TEMPS. MID/UPPER LVL MOISTURE
INCREASES AFT 18Z SUNDAY ACRS OUR WESTERN CWA...AS NEXT S/W TROF
APPROACHES. ON SUNDAY NIGHT...WARM SOUTHERLY FLW WL CONT ACRS OUR
CENTRAL/WESTERN CWA...WITH TEMPS MUCH ABOVE NORMAL ANTICIPATED.
EXPECT LOWS ONLY IN THE U30S TO M40S SUNDAY NIGHT ACRS THE
SLV/CPV...WITH READINGS IN THE 20S ACRS EASTERN VT. BEST DEEP
LAYER MOISTURE AND LIFT WL HOLD OFF UNTIL AFT 12Z
MONDAY...THEREFORE WL CONT TO KEEP A MAINLY DRY FCST THRU THE
PERIOD.
&&
.LONG TERM /MONDAY THROUGH FRIDAY/...
AS OF 315 PM EST FRIDAY...UPPER RIDGE MOVES EAST OF THE AREA
EARLY MONDAY AND PRONOUNCED SOUTHWEST FLOW ALOFT DEVELOPS. WARM
AIR ADVECTION WILL ALLOW TEMPERATURES TO CLIMB WELL INTO THE 40S
AHEAD OF A COLD FRONT...THAT WILL NOT REALLY MOVE INTO THE AREA
UNTIL LATER MONDAY NIGHT. WITH THE HIGHER AMPLITUDE
FLOW...PRECIPITATION WILL BE CLOSELY TIED TO THE UPPER TROUGH
AXIS/COLD FRONT. THUS MOST OF THE AREA WILL STAY DRY WITH SHOWERS
MOVING IN LATE IN THE DAY ON MONDAY...ESPECIALLY OVER NORTHERN NEW
YORK. GIVEN WARM TEMPERATURES...ANY PRECIPITATION WILL FALL IN THE
FORM OF RAIN. COLD FRONT MOVES ACROSS THE AREA LATE MONDAY NIGHT
INTO TUESDAY MORNING AND THIS WILL BE WHEN SHOWERS ARE LIKELY
ACROSS THE ENTIRE AREA. GOING FORECAST HAS THIS COVERED WELL AND
ONLY TWEAK WAS TO KEEP PRECIPITATION LASTING A BIT LONGER TUESDAY
MORNING. THERE IS SOME COLDER AIR MOVING IN ON THE BACKSIDE OF THE
UPPER TROUGH...THUS WE COULD SEE A COUPLE OF INCHES OVER THE
HIGHER TERRAIN VERY LATE MONDAY NIGHT AND ESPECIALLY TUESDAY
MORNING. OTHERWISE...MAIN PRECIPITATION SHIELD MOVES EAST OF THE
AREA TUESDAY AFTERNOON AS UPPER TROUGH AXIS APPROACHES LATE
TUESDAY NIGHT AND ESPECIALLY ON WEDNESDAY. COULD SEE SOME STEEPER
LAPSE RATES KICKING OFF SOME RAIN/SNOW SHOWERS ON WEDNESDAY BEFORE
TROUGH AXIS MOVES EAST AND WE WIND UP IN NORTHWEST FLOW ALOFT.
DESPITE THE NORTHWEST FLOW ALOFT...TEMPERATURES WILL GENERALLY BE
RIGHT AROUND SEASONAL NORMALS DURING THE DAY THURSDAY AND FRIDAY
WITH ABOVE NORMAL TEMPERATURES AT NIGHT. HIGH PRESSURE BUILDING IN
ON THE NORTHWEST FLOW ALOFT THURSDAY AND FRIDAY SUGGESTS DRY
WEATHER WILL BE THE RULE.
&&
.AVIATION /00Z SATURDAY THROUGH WEDNESDAY/...
THROUGH 00Z SUNDAY...PREDOMINANTLY VFR EXPECTED THROUGH THE
PERIOD. MAINLY CLEAR SKIES WITH ONLY FEW-SCT VFR HIGH CLOUDS FOR
TONIGHT. GUSTY WINDS THIS EVENING WILL QUICKLY DIMINISH AFTER 00Z
TO 5 KNOTS OT LESS. THE COMBINATION OF CLEAR SKIES AND LIGHT WINDS
MAY ALLOW FOR SOME DEVELOPMENT OF FOG/BR AT MSS/SLK AFTER 08Z
TONIGHT. HOWEVER WIDESPREAD COVERAGE IS NOT ANTICIPATED SO ONLY
WENT TEMPO 3-4SM BR AT THIS TIME. LOW LEVEL DRYING SHOULD PROHIBIT
FOG DEVELOPMENT AT ANY OTHER SITES. ANY FOG/BR WILL CLEAR AFTER
13Z SATURDAY MORNING WITH CLEAR SKIES EXPECTED FOR THE REMAINDER
OF THE DAY WITH LIGHT NORTH WINDS.
OUTLOOK 00Z SUNDAY THROUGH WEDNESDAY...
00Z SUNDAY THROUGH 12Z MONDAY...VFR UNDER HIGH PRESSURE.
12Z MONDAY THROUGH 00Z WEDNESDAY...PERIODS OF MVFR/IFR POSSIBLE IN
RAIN SHOWERS AS COLD FRONT CROSSES THE REGION.
00Z WEDNESDAY ONWARD...PREDOMINANTLY VFR AS SYSTEM DEPARTS. A FEW
MOUNTAIN SNOW SHOWERS POSSIBLE AT SLK/MPV.
&&
.BTV WATCHES/WARNINGS/ADVISORIES...
VT...NONE.
NY...NONE.
&&
$$
SYNOPSIS...TABER
NEAR TERM...JMG/TABER
SHORT TERM...TABER
LONG TERM...EVENSON
AVIATION...MUCCILLI
AREA FORECAST DISCUSSION
NWS BURLINGTON VT
623 PM EST FRI MAR 8 2013
.SYNOPSIS...
SURFACE HIGH PRESSURE ACROSS THE CENTRAL GREAT LAKES WILL SHIFT INTO
THE NORTHEAST OVER THE WEEKEND. THIS WILL RESULT IN MOSTLY CLEAR
SKIES AND MUCH ABOVE NORMAL TEMPERATURES...ESPECIALLY HIGHS ON
SUNDAY. THE NEXT CHANCE FOR PRECIPITATION MAINLY IN THE FORM OF RAIN
SHOWERS WILL BE LATE MONDAY INTO TUESDAY. A SLOW COOLING TREND WILL
DEVELOP TOWARD THE MIDDLE OF NEXT WEEK.
&&
.NEAR TERM /UNTIL 6 AM SATURDAY MORNING/...
AS OF 623 PM EST FRIDAY...MINOR ADJUSTMENTS AS OF EARLY EVENING
MAINLY TO TWEAK SKY COVER SLIGHTLY...AND BLEND CURRENT T/TD
OBSERVATIONAL DATA AHEAD TO THE MIDNIGHT HOUR OR SO. CURRENT
READINGS ARE RUNNING SOMEWHAT ABOVE PRIOR INDICATIONS...MAINLY DUE
TO CONTINUED WIND/MIXED PBL AND IF LATEST RAP 2M TEMP DATA IS ANY
INDICATION...WE MAY END UP A TAD MILDER OVERNIGHT. NO WHOLESALE
CHANGES IN THAT REGARD AT THIS POINT AS I WANT TO SEE HOW THINGS
TREND OVER THE NEXT FEW HOURS. REST OF FCST REMAINS LARGELY
UNCHANGED. HAVE A GREAT EVENING. PRIOR DISCUSSION FOLLOWS...
TONIGHT...MID/UPPER LVL RIDGE AND ASSOCIATED SFC HIGH PRES WL
SLOWLY MOVE FROM THE CENTRAL GREAT LAKES INTO THE NE CONUS. THIS
WL RESULT IN CLRING SKIES AND LIGHTER WINDS. RAP/GFS AND NAM
SOUNDINGS SHOW PLENTY OF LLVL RH SFC SFC THRU 875MB
TONIGHT...ESPECIALLY AT SLK...BUT BL WINDS REMAIN BTWN 6-10 KNTS.
GIVEN GOOD RADIATIONAL COOLING...EXPECT SFC TEMPS TO REACH SFC
DWPT TEMPS IN DEEPER/SHELTERED VALLEYS...WITH AREAS OF LOW
CLOUDS/FG POSSIBLE...ESPECIALLY NORTHERN NY NEAR SLK. IN
ADDITION...SOUNDINGS SHOW A SHARP INVERSION DEVELOPING WITH
VALLEYS IN THE SINGLE DIGITS/LWR TEENS. MEANWHILE...MTN TOPS/MID
SLOPES HOLD IN THE 20S TO NEAR 30F. AS SOUNDINGS SHOW A THERMAL
BELT BTWN 2KFT AND 3KFT FEET OF TEMPS ABOVE 0C. CPV/SLV TEMPS WL
RANGE IN THE UPPER TEENS TO LOWER 20S...WITH MAINLY SINGLE
DIGITS/TEENS FOR THE NEK.
&&
.SHORT TERM /6 AM SATURDAY MORNING THROUGH SUNDAY NIGHT/...
AS OF 310 PM EST FRIDAY...BY SATURDAY...MID/UPPER LVL RIDGE MOVES
OVERHEAD AND SOUNDINGS SHOW A DEEP DRY LAYER. THIS WL RESULT IN
PLENTY OF SUNSHINE AND LIGHT WINDS. STILL SOME UNCERTAINTY WITH
REGARDS TO AMOUNT OF MIXING...ESPECIALLY OVER THE SNOWPACK ACRS
THE MTN VALLEYS OF THE DACK AND CENTRAL/EASTERN VT. PROGGED 85H
TEMPS WARM TO 0C BY 18Z SAT...BUT SOUNDINGS SHOW MIXING ONLY TO
975MB...WHERE TEMPS ARE BTWN -1C AND -3C...ESPECIALLY CPV AND
DEEPER VALLEYS. THESE THERMAL PROFILES AND SNOWPACK SUGGEST L/M40S
CPV AND PARTS OF THE SLV/DACKS WITH M/U 30S OVER THE SNOWPACK
VALLEYS OF CENTRAL/EASTERN VT...INCLUDING THE NEK. WOULD NOT BE
SURPRISED IF MID SLOPE LOCATIONS BTWN 1200 AND 2500 FEET WARM INTO
THE MID/UPPER 40S SATURDAY...GIVEN THE SHARP VERTICAL THERMAL
GRADIENT. ANY LOW CLOUDS/BR SHOULD BURN OFF BY 14Z SATURDAY.
MID/UPPER LVL RIDGE THEN SHIFTS INTO EASTERN NEW ENGLAND BY 12Z
SUNDAY AS A WARM SOUTHERLY FLW CONTS ACRS OUR CWA. TEMPS WL BE
TRICKY SAT NIGHT/SUNDAY MORNING WITH WARM READINGS IN THE 20S/30S
IN THE MTNS AND COLDEST VALUES IN THE TEENS/LWR 20S IN DEEPER
SNOWPACK VALLEYS. THERMAL PROFILES CONT TO SHOW A SHARP INVERSION
ACRS OUR CWA. ON SUNDAY...HAVE NOTICED SE SFC TO 925MB FLW
DEVELOPING ACRS OUR CENTRAL/EASTERN VT ZNS...WHICH MAY HELP TO
ADVECT A LLVL COOL MARITIME AIRMASS INTO OUR FA. THIS WOULD LIMIT
AMOUNT OF WARMING AND COULD KEEP TEMPS IN CENTRAL/EASTERN VT IN
THE U30S TO M40S. MEANWHILE...NAM12 SHOWS 925MB TEMPS ACRS THE SE
DOWNSLOPE REGIONS OF THE DACKS FROM GOUVERNEUR TO CANTON TO
POTSDAM BTWN 8 AND 10C BY 00Z MONDAY...SUPPORTING HIGHS WELL INTO
THE 50S TO NEAR 60F. PROGGED 925MB TEMPS ACRS EASTERN/CENTRAL
VT...EAST OF THE GREENS ARE ONLY BTWN 2 AND 4C...WITH LIMITED
MIXING...SUPPORTING MUCH COOLER TEMPS. MID/UPPER LVL MOISTURE
INCREASES AFT 18Z SUNDAY ACRS OUR WESTERN CWA...AS NEXT S/W TROF
APPROACHES. ON SUNDAY NIGHT...WARM SOUTHERLY FLW WL CONT ACRS OUR
CENTRAL/WESTERN CWA...WITH TEMPS MUCH ABOVE NORMAL ANTICIPATED.
EXPECT LOWS ONLY IN THE U30S TO M40S SUNDAY NIGHT ACRS THE
SLV/CPV...WITH READINGS IN THE 20S ACRS EASTERN VT. BEST DEEP
LAYER MOISTURE AND LIFT WL HOLD OFF UNTIL AFT 12Z
MONDAY...THEREFORE WL CONT TO KEEP A MAINLY DRY FCST THRU THE
PERIOD.
&&
.LONG TERM /MONDAY THROUGH FRIDAY/...
AS OF 315 PM EST FRIDAY...UPPER RIDGE MOVES EAST OF THE AREA
EARLY MONDAY AND PRONOUNCED SOUTHWEST FLOW ALOFT DEVELOPS. WARM
AIR ADVECTION WILL ALLOW TEMPERATURES TO CLIMB WELL INTO THE 40S
AHEAD OF A COLD FRONT...THAT WILL NOT REALLY MOVE INTO THE AREA
UNTIL LATER MONDAY NIGHT. WITH THE HIGHER AMPLITUDE
FLOW...PRECIPITATION WILL BE CLOSELY TIED TO THE UPPER TROUGH
AXIS/COLD FRONT. THUS MOST OF THE AREA WILL STAY DRY WITH SHOWERS
MOVING IN LATE IN THE DAY ON MONDAY...ESPECIALLY OVER NORTHERN NEW
YORK. GIVEN WARM TEMPERATURES...ANY PRECIPITATION WILL FALL IN THE
FORM OF RAIN. COLD FRONT MOVES ACROSS THE AREA LATE MONDAY NIGHT
INTO TUESDAY MORNING AND THIS WILL BE WHEN SHOWERS ARE LIKELY
ACROSS THE ENTIRE AREA. GOING FORECAST HAS THIS COVERED WELL AND
ONLY TWEAK WAS TO KEEP PRECIPITATION LASTING A BIT LONGER TUESDAY
MORNING. THERE IS SOME COLDER AIR MOVING IN ON THE BACKSIDE OF THE
UPPER TROUGH...THUS WE COULD SEE A COUPLE OF INCHES OVER THE
HIGHER TERRAIN VERY LATE MONDAY NIGHT AND ESPECIALLY TUESDAY
MORNING. OTHERWISE...MAIN PRECIPITATION SHIELD MOVES EAST OF THE
AREA TUESDAY AFTERNOON AS UPPER TROUGH AXIS APPROACHES LATE
TUESDAY NIGHT AND ESPECIALLY ON WEDNESDAY. COULD SEE SOME STEEPER
LAPSE RATES KICKING OFF SOME RAIN/SNOW SHOWERS ON WEDNESDAY BEFORE
TROUGH AXIS MOVES EAST AND WE WIND UP IN NORTHWEST FLOW ALOFT.
DESPITE THE NORTHWEST FLOW ALOFT...TEMPERATURES WILL GENERALLY BE
RIGHT AROUND SEASONAL NORMALS DURING THE DAY THURSDAY AND FRIDAY
WITH ABOVE NORMAL TEMPERATURES AT NIGHT. HIGH PRESSURE BUILDING IN
ON THE NORTHWEST FLOW ALOFT THURSDAY AND FRIDAY SUGGESTS DRY
WEATHER WILL BE THE RULE.
&&
.AVIATION /23Z FRIDAY THROUGH WEDNESDAY/...
THROUGH 18Z SATURDAY...LARGE CLOUD SHIELD CONTINUES TO MOVE SOUTH
THIS AFTERNOON AND MOST LOCATIONS ARE REPORTING VFR CEILINGS AND
VISIBILITIES. THE ONLY EXCEPTION TO THIS IS AT KBTV AND KPBG WHERE
MVFR CEILINGS EXIST EARLY THIS AFTERNOON...BUT SHOULD BECOME VFR
BY 22Z. EXPECT VFR CONDITIONS FOR THE REMAINDER OF THE PERIOD WITH
THE ONLY EXCEPTION BEING KSLK...WHERE MVFR CEILINGS AND
VISIBILITIES WILL DEVELOP BETWEEN 06Z AND 13Z. WIND GUSTS FROM THE
NORTH WILL CONTINUE IN THE 15 TO 25 KNOT RANGE THIS AFTERNOON...BUT
DROP QUICKLY AROUND 00Z. LIGHT AND VARIABLE WINDS ARE THEN
EXPECTED FOR THE REMAINDER OF THE PERIOD.
OUTLOOK 18Z SATURDAY THROUGH TUESDAY...
18Z SATURDAY THROUGH 18Z SUNDAY...VFR UNDER HIGH PRESSURE.
18Z SUNDAY THROUGH TUESDAY...VFR TRENDING TO MVFR IN PERIODS OF
RAIN/SNOW SHOWERS AS A COLD FRONT PUSHES THROUGH THE REGION. BRIEF
IFR POSSIBLE IN HEAVIER SNOW.
&&
.BTV WATCHES/WARNINGS/ADVISORIES...
VT...NONE.
NY...NONE.
&&
$$
SYNOPSIS...TABER
NEAR TERM...JMG/TABER
SHORT TERM...TABER
LONG TERM...EVENSON
AVIATION...EVENSON/LAHIFF
AREA FORECAST DISCUSSION
NWS BINGHAMTON NY
109 AM EST THU MAR 7 2013
.SYNOPSIS...
A WINTER STORM WILL MOVE OFF THE MID ATLANTIC COAST AND SLOW DOWN
AS IT MOVES UP THE NORTHEASTERN SEABOARD TONIGHT THROUGH THURSDAY
NIGHT. AN UPPER LEVEL LOW WILL TRACK SOUTHEAST FROM THE UPPER
GREAT LAKES TONIGHT THROUGH THURSDAY NIGHT AND SPREAD MORE SNOW TO
MUCH OF CENTRAL NEW YORK AND NORTHEAST PENNSYLVANIA THURSDAY
AFTERNOON AND NIGHT. THE SNOW COULD MIX WITH RAIN AT TIMES IN THE
VALLEYS THURSDAY AFTERNOON. ALL THE PRECIPITATION WILL TAPER OFF
FRIDAY. HIGH PRESSURE AND MILDER WEATHER WILL MOVE INTO THE REGION
FOR THE WEEKEND.
&&
.NEAR TERM /THROUGH TODAY/...
RECENT RADAR TRENDS SHOWING ANY LINGERING SNOW ACTIVITY QUICKLY
EXITING OFF THE EAST COAST THIS EVENING AS MAIN SFC LOW CONTINUES
TO EXIT TOWARDS THE 40N/70W BENCHMARK. LATEST HRRR AND NEWLY
ARRIVING 00Z NAM BOTH VALIDATE CURRENT RADAR TRENDS AND KEEP ANY
QPF OVERNIGHT EAST OF THE CWA. AS A RESULT...HAVE TRIMMED BACK ON
POPS ACCORDINGLY AND FEEL MUCH IF NOT THE WHOLE NIGHT SHOULD BE
PRECIP FREE. ASIDE FROM THAT...HOURLY TEMPS ADJUSTED AS COLD AIR
ADVECTION ON BACKSIDE OF DEPARTING LOW HAS YET TO ARRIVE. BY EARLY
MORNING...LOWS SHOULD BOTTOM OUT TOWARDS THE UPPER 20S ACROSS MOST
LOCATIONS.
&&
.SHORT TERM /TONIGHT THROUGH SATURDAY/...
1025 PM UPDATE...
NEWLY ARRIVING 00Z MODEL GUIDANCE FURTHER SUPPORTING CONCERNS FOR
SNOWFALL BEGINNING LATE THURSDAY AFTERNOON AS WRAP AROUND MOISTURE
ON THE BACKSIDE OF AFOREMENTIONED UPPER LOW GETS PULLED WESTWARD
IN ADVANCE OF ANOTHER NORTHERN STREAM TROUGH/CLOSED LOW DIVING
SOUTHEAST FROM THE NORTHERN LAKES. IN FACT...LATEST WATER VAPOR
IMAGERY NOW SHOWING THE APPROACHING WAVE QUITE WELL AND THIS
FEATURE WILL CONTINUE DIVING SOUTHEAST THROUGH CENTRAL PA THU
NGT/EARLY FRI. 24-HR QPF TOTALS FROM THE NAM SUGGEST OVER 1" OF
WATER EQUIVALENT FOR THE EASTERN ZONES...WITH UP TO .7" AS FAR
WEST AS THE I-81 CORRIDOR. FOR WHAT ITS WORTH...18Z GFS ALSO
SHOWING SOME WESTWARD DISPLACEMENT OF MAIN QPF AXIS WHICH LENDS
SUPPORT TO AT LEAST HIGH-END ADVISORY SNOWFALLS FOR THE EASTERN
ZONES. FOR NOW...WILL HOLD OFF ON MAKING ANY WHOLESALE CHANGES AND
ALLOW THE OVERNIGHT SHIFT TO EVALUATE THE FULL MODEL SUITE BEFORE
MAKING ANY HEADLINE ADJUSTMENTS.
PREVIOUS SHORT TERM DISCUSSION...
WATER VAPOR IMAGERY SHOWS A POTENT UPPER LEVEL LOW DIVING
SOUTHEASTWARD FROM THE UPPER GREAT LAKES AT PRESENT. THIS FEATURE
WILL CONT SE REACHING WRN NY THU EVE AND THEN DOWN TO THE DELMARVA
PENINSULA BY 12Z FRI. MEANWHILE THE LARGE CYCLONE THAT WAS MOVG
THRU THE MID- ATLANTIC STATES AT PRESENT WILL MOVE OFFSHORE BUT
SLOW DOWN AND EXPAND ITS LOW TO MID LEVEL EASTERLY FLOW TO
ENCOMPASS ALL OF C NY AND NE PA THU AFTERNOON AND NIGHT. MOISTURE
ADVECTION IN THIS LOW TO MID LEVEL EASTERLY FLOW WILL RISE
ISENTROPICALLY ESP ACRS ERN NY AND NE PA AS THE UPPER LEVEL LOW
MOVING SE ALSO LIFTS THE ISENTROPES. THIS IS AN EXCELLENT
DYNAMICAL SET-UP TO FORCE PRECIPITATION OVER MUCH OF C NY/NE PA
LATE THU AFTERNOON AND NIGHT. SINCE MOST OF THE PRECIPITATION WILL
FALL AT NIGHT AND ALSO FOCUS ON OUR HIGHER TERRAIN AREAS IN
OTSEGO...DELAWARE AND SULLIVAN CO/S IT WILL BE MAINLY SNOW.
HEAVIEST PRECIPITATION WILL BE IN OUR EASTERN ZONES WHERE THE
LIFTG WILL BE THE HIGHEST AND THE MOISTURE WILL BE DEEPER.
HENCE OPTED FOR A WINTER WX ADVY IN DELAWARE...OTSEGO AND SULLIVAN
CO/S THU PM TO FRI AM GIVEN THE CONSENSUS OF THE 12Z GFS...12Z
CMC...12Z HI RES NMM...AND THE 15Z SREF. BLENDED MODEL SNOWFALL
FROM THESE SOURCES AND CAME UP WITH BASICALLY 3-4 INCHES IN THE
DEEPEST VALLEYS OF DELAWARE...SULLIVAN AND OTSEGO CO/S TO 6-8
INCHES OVER THE HIGHEST TERRAIN. MOST OF THESE COUNTIES ARE FAIRLY
ELEVATED SO MOST AREAS LIKELY WILL SEE 4-6 INCHES. REST OF C NY
AND NE PA LIKELY WILL SEE LESS THAN 1 INCH IN VALLEYS TO AS MUCH
AS 3 INCHES HIGHER TERRAIN ALONG THE I-81 CORRIDOR IN NY. WE
DISCOUNTED THE NAM WHICH BURIES THE POCONOS AND CATSKILLS WITH
10-20 INCHES OF SNOW AND GIVES A LARGE PART OF THE REST OF OUR
AREA 5-10 INCHES OF SNOW. BUT THIS TYPE OF SCENARIO DOES BEAR
WATCHING AS THEIR IS STRG MID-LVL FGEN FRCG IN THE PRESENCE OF
WEAK TO NEGATIVE EPV IN THESE AREAS. FOR NOW WAY TOO UNCERTAIN TO
JUMP ON THIS BAND WAGON AND GIVEN THE TRACK RECORD OF THE NAM/S
SNOWFALL RECENTLY WE DID NOT USE FOR NOW.
THE SNOW PEAKS THURSDAY NIGHT AND TAPERS DOWN TO SNOW SHOWERS
FLURRIES AND POTENTIALLY EVEN SOME SPRINKLES/RAIN SHOWERS IN THE
LOWER ELEVATIONS FRIDAY.
FRIDAY NIGHT AND SATURDAY LOOK FAIR WITH MILDER TEMPERATURES ON
SATURDAY AS A RDG OF HIGH PRESSURE BUILDS IN.
&&
.LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/...
GIVEN TDA`S FOCUS ON SHORT TERM CONCERNS...WE USED HPC GUIDANCE
FOR THE MED RNG. WE DID MAKE SOME MINOR TWEEKS...PRIMARILY TO CLD
COVER (MORE PESSIMISTIC) AND TO A LESSER XTNT WINDS AND TEMPS AS A
BACK DOOR CDFNT TRIES TO DROP SWD ON SUN NGT. THIS FEATURE COULD
HAVE A SIG EFFECT ON TEMPS ACRS NRN ZONES ON MON...IN ADVANCE OF
THE OCCLUDED FNT FCST TO PASS LATE ON MON NGT. AFTER SOME MILD
TEMPS THIS WEEKEND...READINGS WILL COOL BY MID WEEK TO MORE
SEASONABLE VALUES.
&&
.AVIATION /06Z THURSDAY THROUGH MONDAY/...
A THICK VFR STRATUS DECK WILL HANG OVER THE TERMINALS INTO THE
AFTERNOON HOURS ON THURSDAY. TEMPO MVFR CEILINGS ARE POSSIBLE AT
KBGM MAINLY DUE TO ELEVATION EFFECTS.
A STORM SYSTEM OFF THE ATLANTIC COAST WILL WRAP MOISTURE BACK
ACROSS NY AND PA THURSDAY NIGHT. SNOW MAY REACH INTO THE I-81
CORRIDOR, BRINGING LOW MVFR AND TEMPO IFR RESTRICTIONS TO MOST OF
THE TERMINALS. TIMING SUGGESTS THE SNOW WILL BEGIN BETWEEN 23Z AND
02Z, AND CONTINUE THROUGH LATE MORNING FRIDAY. THE BEST CHANCE FOR
LONG TERM RESTRICTIONS WILL BE AT AVP AND BGM.
.OUTLOOK...
FRI/SAT/SUN...MVFR IN -SN INTO MIDDAY FRI. VFR OTHERWISE.
MON...MVFR IN -SHRA.
&&
.BGM WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NY...WINTER WEATHER ADVISORY FROM 1 PM THIS AFTERNOON TO 11 AM EST
FRIDAY FOR NYZ046-057-062.
&&
$$
SYNOPSIS...DJN
NEAR TERM...CMG/DJN
SHORT TERM...DJN
LONG TERM...
AVIATION...DJP
AREA FORECAST DISCUSSION
NWS RALEIGH NC
1150 AM EST THU MAR 7 2013
.SYNOPSIS...
STRONG LOW PRESSURE OFF THE MIDATLANTIC COAST WILL MOVE FURTHER OUT
TO SEA TODAY. DRY HIGH PRESSURE WILL BUILD INTO THE REGION THIS
AFTERNOON... AND LINGER THROUGH THE WEEKEND.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 1022 AM THURSDAY...
REST OF TODAY: A MUCH QUIETER DAY THAN THE LAST FEW... ALTHOUGH
WE`LL STILL SEE SOME CLOUDINESS (ESPECIALLY FAR WEST AND IN THE
NORTHEAST) ALONG WITH BELOW-NORMAL TEMPS AND GUSTY WINDS. THE
POWERFUL STORM SYSTEM IS CENTERED WELL OFF THE MIDATLANTIC COAST
ACCORDING TO THE LATEST SURFACE ANALYSIS... ALTHOUGH ITS CIRCULATION
WILL CONTINUE TO PULL LOW LEVEL MOISTURE (BENEATH THE SUBSIDENCE
INVERSION ALOFT) INTO NORTH CENTRAL AND NORTHEAST NC. 925-850 MB
PROGS FROM THE 12KM NAM AS WELL AS THE HRRR INDICATE STRATOCU
SPREADING TO THE SSE INTO THIS AREA TODAY... AND MORNING SOUNDINGS
AND TRAJECTORIES ALONG WITH SATELLITE IMAGERY SUPPORT A PERIOD OF
PARTLY SUNNY TO MOSTLY CLOUDY SKIES OVER THE COASTAL PLAIN AND
NORTHEAST PIEDMONT THROUGH THE REST OF THE DAY. OVER THE FAR WESTERN
PIEDMONT... OROGRAPHICALLY ENHANCED CIRRUS IS LIKELY TO PERSIST FOR
A FEW MORE HOURS GIVEN THAT OBSERVED AND FORECAST SOUNDINGS SHOW A
FAVORABLE WIND PROFILE. THE THICKER CLOUDS IN THE NORTHEAST WILL
IMPACT TEMPS... AS SUGGESTED BY THE LATEST HRRR OUTPUT... SUGGESTING
HIGHS THERE IN THE LOWER 50S... WHEREAS AREAS FROM THE TRIANGLE AND
TRIAD TO THE SOUTH AND SW SHOULD SEE HIGHS IN THE MID-UPPER 50S. THE
MIXED LAYER NOTED IN FORECAST SOUNDINGS SUPPORTS GUSTS AROUND 20-25
MPH IN THE FAR NORTHEAST (NEAREST THE TIGHTER MSLP GRADIENT) BUT
JUST 15-20 ELSEWHERE... BEFORE THE DEPARTURE OF THE STORM SYSTEM
RESULTS IN A SLOW DIMINISHING OF WINDS TOWARD NIGHTFALL. -GIH
TONIGHT...STRONG VORT MAX IN THE NW FLOW ALOFT WILL DROP SEWD FROM
THE NORTHERN GREAT LAKES INTO NORTHERN MID ATLANTIC TONIGHT THEN OFF
THE VIRGINIA CAPE BY EARLY FRI. THIS SYSTEM WILL BE MOISTURE STARVED
SO EXPECT LITTLE IN THE MANNER OF CLOUDS. HOWEVER...THIS SYSTEM WILL
MAINTAIN A FAIRLY TIGHT PRESSURE GRADIENT SO WINDS WILL MAINTAIN
5-9KTS OVERNIGHT. THIS MIXING WILL AID TO KEEP TEMPS UP A BIT. IF
SFC WINDS DECOUPLE...MORE LIKELY IN THE WESTERN PIEDMONT...COULD SEE
TEMPS TUMBLE 4-5 DEGREES COLDER THAN FORECAST. MIN TEMPS UPPER 20S
WEST TO LOWER 30S COASTAL PLAIN. -WSS
&&
.SHORT TERM /FRIDAY AND FRIDAY NIGHT/...
AS OF 300 AM THURSDAY...
FRIDAY AND FRIDAY NIGHT...AS STRONG VORT EXITS OFF THE MID ATLANTIC
COAST...LOW LEVEL FLOW WILL BECOME MORE N-NE. SOME MODELS
(ESPECIALLY NAM) DEPICT MORE OF A FETCH OFF THE ATLANTIC WHILE THE
GFS AND ECMWF MAINTAIN A NLY FLOW (MAINLY OVER LAND). CONSIDERING
THE AMOUNT OF MOISTURE ON THE BACK SIDE OF THE DEEP LOW...NAM MAY BE
ONTO SOMETHING. THUS HAVE INCREASED CLOUD COVERAGE IN THE EAST LATE
FRI INTO FRIDAY NIGHT. WITH A FEW MORE CLOUDS EXPECTED NE VERSUS
SW...SHOULD SEE COOLER MAX TEMPS NE AND WARMER SW. MAX TEMPS NEAR 50
NORTHERN COASTAL PLAIN TO MID-UPPER 50S SW. MIN TEMPS FRIDAY NIGHT
HIGHLY DEPENDENT ON EXTENT OF CLOUD COVERAGE. USED A BLEND OF MOS
GUIDANCE FOR MIN TEMPS. HOWEVER IF CLOUDS DO MATERIALIZE...MIN TEMPS
WILL NEED TO BE ADJUSTED UP A FEW DEGREES. CONVERSELY...IF CLOUDS DO
NOT FORM AND SFC WINDS DECOUPLE...MIN TEMPS WILL NEED TO BE ADJUSTED
DOWN 4-5 DEGREES.
&&
.LONG TERM /SATURDAY THROUGH WEDNESDAY/...
AS OF 250 AM THURSDAY...
THIS WEEKEND: BENEATH A BUILDING AND SLOWLY PROGRESSIVE RIDGE
ALOFT...1030 MB SURFACE HIGH PRESSURE WILL SPAN THE LENGTH OF THE
EAST COAST. THE RIDGING WILL PROVIDE FOR GENERALLY CLEAR AND
MODERATING CONDITIONS FOR CENTRAL NC...WITH THE ONLY APPRECIABLE
CLOUD COVER...ASIDE FROM CIRRUS...LIKELY TO HOLD WEST OF THE YADKIN
IN RETURN LOW LEVEL FLOW SUN NIGHT-MON MORNING. STEADILY RISING
THICKNESSES SUGGEST HIGHS AROUND 60 DEGREES SAT...AND IN THE
LOWER-MIDDLE 60S SUN. BELOW GUIDANCE LOWS IN THE 29 TO 34 DEGREE
RANGE WITH EXCELLENT RADIATIONAL SAT NIGHT...AND ABOUT 10 DEGREES
MILDER SUN NIGHT.
MONDAY THROUGH WEDNESDAY: THE DEEP LAYER RIDGING WILL CONTINUE
EASTWARD IN THE AFOREMENTIONED SLOWLY PROGRESSIVE FLOW...IN ADVANCE
OF A COMPLEX TROUGH ALOFT OVER AND OFFSHORE THE PAC NW COAST THIS
MORNING. MEDIUM RANGE GUIDANCE IS IN REASONABLY GOOD AGREEMENT
REGARDING THE PROGRESSION OF THIS TROUGH AND ACCOMPANYING WET LOW
LEVEL FRONTAL ZONE ACROSS CENTRAL NC MON NIGHT-TUE...WITH A
PRECEDING RESIDUAL CAPPING INVERSION LIKELY TO HOLD THROUGH THE DAY
MON. INHERENT UNCERTAINTY AT THIS TIME RANGE FAVORS HOLDING POP IN
THE 50-60 PERCENT RANGE...BUT CATEGORICAL PROBABILITIES WILL
ULTIMATELY BE WARRANTED WITH TIME GIVEN THE EXPECTED WIDE-OPEN AND
STRONG GULF INFLOW INTO THE FRONTAL ZONE. POST-FRONTAL COOLER AND
DRIER CONDITIONS WILL PREVAIL FOR MID-LATE WEEK.
&&
.AVIATION /18Z THURSDAY THROUGH TUESDAY/...
AS OF 1150 AM THURSDAY...
HIGH CONFIDENCE IN CONTINUED VFR CONDITIONS THROUGH FRIDAY. THE LOW
PRESSURE SYSTEM FROM THE LAST FEW DAYS WILL CONTINUE A STEADY
EASTWARD DRIFT OUT TO SEA TODAY... HOWEVER THE CIRCULATION WILL
STILL INFLUENCE US AS WE WILL MAINTAIN A MAINLY NORTHERLY BREEZE
THIS AFTERNOON -- STRONGER (10-15 KTS GUSTING TO 20-25 KTS) AT RWI
TAPERING WEAKER (AROUND 10 KTS WITH INFREQUENT GUSTS AROUND 15 KTS)
AT INT/GSO. SURFACE HIGH PRESSURE CENTERED OVER ONTARIO AND THE
UPPER GREAT LAKES WILL EXTEND WELL SOUTHWARD... BUILDING SLOWLY
EASTWARD OVER EASTERN NOAM OVER THE NEXT 36 HOURS. ANY CLOUDS TODAY
WILL BE BASED ABOVE 3 THOUSAND FT AGL... MOST EXTENSIVE AT
RWI/RDU/FAY. SKIES WILL BECOME UNLIMITED THIS EVENING AND REMAIN SO
WELL INTO FRIDAY WITH JUST LIGHT (10 KTS OR LOWER) WINDS FROM THE
NORTH.
LOOKING BEYOND FRIDAY AFTERNOON... MID-LEVEL LOW PRESSURE OVER LAKE
SUPERIOR THIS MORNING WILL DROP SOUTHEASTWARD BRUSHING NORTHEAST NC
LATE FRIDAY INTO FRIDAY NIGHT... AND THIS MAY BRING A PERIOD OF
SCT-BKN CLOUDS AT 2500-3000 FT AGL LATE FRIDAY NIGHT AT RDU/RWI.
OTHERWISE VFR CONDITIONS WILL HOLD INTO LATE SUNDAY MORNING THROUGH
MONDAY MORNING... WHEN MOIST LOW LEVEL FLOW WILL BRING A RISK OF IFR
CONDITIONS. BREEZY WINDS FROM THE SOUTHWEST AND MVFR CIGS/VSBYS WITH
SHOWERS ARE POSSIBLE LATE MONDAY INTO TUESDAY AS FRONTAL SYSTEM
CROSSES THE REGION. -GIH
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...HARTFIELD
NEAR TERM...HARTFIELD/WSS
SHORT TERM...WSS
LONG TERM...MWS
AVIATION...HARTFIELD
AREA FORECAST DISCUSSION
NWS RALEIGH NC
1022 AM EST THU MAR 7 2013
.SYNOPSIS...
STRONG LOW PRESSURE OFF THE MIDATLANTIC COAST WILL MOVE FURTHER OUT
TO SEA TODAY. DRY HIGH PRESSURE WILL BUILD INTO THE REGION THIS
AFTERNOON... AND LINGER THROUGH THE WEEKEND.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 1022 AM THURSDAY...
REST OF TODAY: A MUCH QUIETER DAY THAN THE LAST FEW... ALTHOUGH
WE`LL STILL SEE SOME CLOUDINESS (ESPECIALLY FAR WEST AND IN THE
NORTHEAST) ALONG WITH BELOW-NORMAL TEMPS AND GUSTY WINDS. THE
POWERFUL STORM SYSTEM IS CENTERED WELL OFF THE MIDATLANTIC COAST
ACCORDING TO THE LATEST SURFACE ANALYSIS... ALTHOUGH ITS CIRCULATION
WILL CONTINUE TO PULL LOW LEVEL MOISTURE (BENEATH THE SUBSIDENCE
INVERSION ALOFT) INTO NORTH CENTRAL AND NORTHEAST NC. 925-850 MB
PROGS FROM THE 12KM NAM AS WELL AS THE HRRR INDICATE STRATOCU
SPREADING TO THE SSE INTO THIS AREA TODAY... AND MORNING SOUNDINGS
AND TRAJECTORIES ALONG WITH SATELLITE IMAGERY SUPPORT A PERIOD OF
PARTLY SUNNY TO MOSTLY CLOUDY SKIES OVER THE COASTAL PLAIN AND
NORTHEAST PIEDMONT THROUGH THE REST OF THE DAY. OVER THE FAR WESTERN
PIEDMONT... OROGRAPHICALLY ENHANCED CIRRUS IS LIKELY TO PERSIST FOR
A FEW MORE HOURS GIVEN THAT OBSERVED AND FORECAST SOUNDINGS SHOW A
FAVORABLE WIND PROFILE. THE THICKER CLOUDS IN THE NORTHEAST WILL
IMPACT TEMPS... AS SUGGESTED BY THE LATEST HRRR OUTPUT... SUGGESTING
HIGHS THERE IN THE LOWER 50S... WHEREAS AREAS FROM THE TRIANGLE AND
TRIAD TO THE SOUTH AND SW SHOULD SEE HIGHS IN THE MID-UPPER 50S. THE
MIXED LAYER NOTED IN FORECAST SOUNDINGS SUPPORTS GUSTS AROUND 20-25
MPH IN THE FAR NORTHEAST (NEAREST THE TIGHTER MSLP GRADIENT) BUT
JUST 15-20 ELSEWHERE... BEFORE THE DEPARTURE OF THE STORM SYSTEM
RESULTS IN A SLOW DIMINISHING OF WINDS TOWARD NIGHTFALL. -GIH
TONIGHT...STRONG VORT MAX IN THE NW FLOW ALOFT WILL DROP SEWD FROM
THE NORTHERN GREAT LAKES INTO NORTHERN MID ATLANTIC TONIGHT THEN OFF
THE VIRGINIA CAPE BY EARLY FRI. THIS SYSTEM WILL BE MOISTURE STARVED
SO EXPECT LITTLE IN THE MANNER OF CLOUDS. HOWEVER...THIS SYSTEM WILL
MAINTAIN A FAIRLY TIGHT PRESSURE GRADIENT SO WINDS WILL MAINTAIN
5-9KTS OVERNIGHT. THIS MIXING WILL AID TO KEEP TEMPS UP A BIT. IF
SFC WINDS DECOUPLE...MORE LIKELY IN THE WESTERN PIEDMONT...COULD SEE
TEMPS TUMBLE 4-5 DEGREES COLDER THAN FORECAST. MIN TEMPS UPPER 20S
WEST TO LOWER 30S COASTAL PLAIN. -WSS
&&
.SHORT TERM /FRIDAY AND FRIDAY NIGHT/...
AS OF 300 AM THURSDAY...
FRIDAY AND FRIDAY NIGHT...AS STRONG VORT EXITS OFF THE MID ATLANTIC
COAST...LOW LEVEL FLOW WILL BECOME MORE N-NE. SOME MODELS
(ESPECIALLY NAM) DEPICT MORE OF A FETCH OFF THE ATLANTIC WHILE THE
GFS AND ECMWF MAINTAIN A NLY FLOW (MAINLY OVER LAND). CONSIDERING
THE AMOUNT OF MOISTURE ON THE BACK SIDE OF THE DEEP LOW...NAM MAY BE
ONTO SOMETHING. THUS HAVE INCREASED CLOUD COVERAGE IN THE EAST LATE
FRI INTO FRIDAY NIGHT. WITH A FEW MORE CLOUDS EXPECTED NE VERSUS
SW...SHOULD SEE COOLER MAX TEMPS NE AND WARMER SW. MAX TEMPS NEAR 50
NORTHERN COASTAL PLAIN TO MID-UPPER 50S SW. MIN TEMPS FRIDAY NIGHT
HIGHLY DEPENDENT ON EXTENT OF CLOUD COVERAGE. USED A BLEND OF MOS
GUIDANCE FOR MIN TEMPS. HOWEVER IF CLOUDS DO MATERIALIZE...MIN TEMPS
WILL NEED TO BE ADJUSTED UP A FEW DEGREES. CONVERSELY...IF CLOUDS DO
NOT FORM AND SFC WINDS DECOUPLE...MIN TEMPS WILL NEED TO BE ADJUSTED
DOWN 4-5 DEGREES.
&&
.LONG TERM /SATURDAY THROUGH WEDNESDAY/...
AS OF 250 AM THURSDAY...
THIS WEEKEND: BENEATH A BUILDING AND SLOWLY PROGRESSIVE RIDGE
ALOFT...1030 MB SURFACE HIGH PRESSURE WILL SPAN THE LENGTH OF THE
EAST COAST. THE RIDGING WILL PROVIDE FOR GENERALLY CLEAR AND
MODERATING CONDITIONS FOR CENTRAL NC...WITH THE ONLY APPRECIABLE
CLOUD COVER...ASIDE FROM CIRRUS...LIKELY TO HOLD WEST OF THE YADKIN
IN RETURN LOW LEVEL FLOW SUN NIGHT-MON MORNING. STEADILY RISING
THICKNESSES SUGGEST HIGHS AROUND 60 DEGREES SAT...AND IN THE
LOWER-MIDDLE 60S SUN. BELOW GUIDANCE LOWS IN THE 29 TO 34 DEGREE
RANGE WITH EXCELLENT RADIATIONAL SAT NIGHT...AND ABOUT 10 DEGREES
MILDER SUN NIGHT.
MONDAY THROUGH WEDNESDAY: THE DEEP LAYER RIDGING WILL CONTINUE
EASTWARD IN THE AFOREMENTIONED SLOWLY PROGRESSIVE FLOW...IN ADVANCE
OF A COMPLEX TROUGH ALOFT OVER AND OFFSHORE THE PAC NW COAST THIS
MORNING. MEDIUM RANGE GUIDANCE IS IN REASONABLY GOOD AGREEMENT
REGARDING THE PROGRESSION OF THIS TROUGH AND ACCOMPANYING WET LOW
LEVEL FRONTAL ZONE ACROSS CENTRAL NC MON NIGHT-TUE...WITH A
PRECEDING RESIDUAL CAPPING INVERSION LIKELY TO HOLD THROUGH THE DAY
MON. INHERENT UNCERTAINTY AT THIS TIME RANGE FAVORS HOLDING POP IN
THE 50-60 PERCENT RANGE...BUT CATEGORICAL PROBABILITIES WILL
ULTIMATELY BE WARRANTED WITH TIME GIVEN THE EXPECTED WIDE-OPEN AND
STRONG GULF INFLOW INTO THE FRONTAL ZONE. POST-FRONTAL COOLER AND
DRIER CONDITIONS WILL PREVAIL FOR MID-LATE WEEK.
&&
.AVIATION /12Z THURSDAY THROUGH MONDAY/...
AS OF 625 AM THURSDAY...
VFR CONDITIONS ARE EXPECTED ACROSS CENTRAL NC TODAY THROUGH
FRIDAY. A DEEP LOW PRESSURE SYSTEM OFFSHORE WILL CONTINUE TO
INFLUENCE OUR SENSIBLE WEATHER. PRONOUNCED CYCLONIC FLOW WILL RESULT
IN BREEZY CONDITIONS TODAY WITH FREQUENT GUSTS 20-25KTS...ESPECIALLY
OVER THE COASTAL PLAIN (KRWI). NLY FLOW IN THE 925-850MB LAYER HAS
ADVECTED MOISTURE INTO THE WESTERN PIEDMONT...RESULTING IN A DECK OF
STRATUS BETWEEN 3500-4500FT. AS LOW LEVEL FLOW BACKS AND BECOMES
NW...CLOUD COVERAGE WILL DIMINISH. OTHERWISE A DECK OF STRATOCU WILL
DEVELOP LATER THIS MORNING WITH BASES BETWEEN 4000-5000FT. THIS
CLOUD DECK SHOULD BE RELATIVELY THIN AND SHOULD DISSIPATE WITHIN A
FEW HOURS AFTER SUNSET.
HIGH PRESSURE WILL BEGIN TO EXERT ITS INFLUENCE ON OUR WEATHER
FRIDAY AND MORE SO SATURDAY INTO SUNDAY AS THIS WEATHER FEATURE WILL
EXTEND SW-NE ACROSS THE AREA. MAINLY CLEAR SKIES AND LIGHT WINDS
WILL BE ASSOCIATED WITH THE HIGH. THE HIGH WILL DRIFT EAST
MONDAY...SETTING UP A RETURN FLOW REGIME...LEADING TO MORE CLOUDS.
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...HARTFIELD
NEAR TERM...HARTFIELD/WSS
SHORT TERM...WSS
LONG TERM...MWS
AVIATION...WSS
AREA FORECAST DISCUSSION
NWS CHARLESTON WV
300 PM EST THU MAR 7 2013
.SYNOPSIS...
LOW PRESSURE OFF THE EAST COAST DRIFTS SLOWLY AWAY THROUGH
FRIDAY...ALLOWING HIGH PRESSURE TO BUILD IN THIS WEEKEND. A COLD
FRONT AND WAVE OF LOW PRESSURE MOVE THROUGH EARLY NEXT WEEK.
&&
.NEAR TERM /THROUGH FRIDAY NIGHT/...
STILL COULD SEE A PEAK OF SUN OR TWO INTO THE KANAWHA VALLEY THIS
AFTERNOON...BUT CANNOT ELIMINATING THE LOW LEVEL MOISTURE IN
PLACE DOWNWIND OF THE GREAT LAKES. RUC HAS THE STRATUS DECK THROUGH
05Z TONIGHT...AND OTHER MODELS DRYING OUT THE WESTERN LOWLANDS AFTER
06Z. THE SUN MAKES AN APPEARANCE FRIDAY WITH HIGH PRESSURE DRIFTING
ACROSS THE SOUTHERN GREAT LAKES AND DRYING LOW LEVELS. NAM AT 925MB
STILL HAS NORTHERLY FLOW AND SATURATION IN A LINGERING THERMAL
TROUGH...SO KEPT THE CLOUDS IN PLACE OVER THE TYGART AND GREENBRIER
VALLEYS. WILL SEE A SLOW IMPROVEMENT TO THE 850MB TEMPERATURES...BUT
WILL NOT QUITE GET INTO THE EFFICIENT WARM UP WITH A NORTHERLY
COMPONENT TO THE WIND AT THE SURFACE AN LOW LEVELS THROUGH 00Z
SATURDAY.
&&
.SHORT TERM /SATURDAY THROUGH SUNDAY/...
HIGH PRESSURE IS IN CONTROL AT THE SURFACE FOR THE FIRST HALF OF THE
WEEKEND...WITH A RIDGE BUILDING IN ALOFT. THIS WILL SPELL ABOVE
NORMAL AFTERNOON HIGHS ACROSS MUCH OF THE FORECAST AREA. HIGHS MAY
BE TEMPERED A BIT BY LINGERING SNOW COVER IN THE NORTHERN MOUNTAINS
OF WEST VIRGINIA SO STAY A BIT BELOW GUIDANCE THERE. MODEL TIMING A
LITTLE DIFFERENT ON WHEN THE LEADING PRECIP AHEAD OF THE NEXT SYSTEM
MAY ENTER OUR WESTERN ZONES. ONLY MADE LITTLE CHANGES FROM PREVIOUS
POP FORECAST...WITH SLIGHT CHANCE POPS ENTERING FROM THE WEST
SATURDAY AFTERNOON. DESPITE INCREASING HIGH CLOUDS...SUNDAY SHOULD
BE THE WARMER DAY OF THE WEEKEND...WITH LOW TO MID 60S PRETTY
WIDESPREAD ACROSS THE LOWER ELEVATIONS...AND UPPER 40S TO 50S IN THE
MOUNTAINS AS SNOW PACK CONTINUES TO MELT.
&&
.LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/...
MOISTURE FROM THE LEADING EDGE OF THE NEXT FRONTAL SYSTEM WILL BEGIN
TO SPREAD OVER THE WESTERN PORTIONS OF THE FORECAST AREA LATE SUNDAY
NIGHT AS THE WEEKENDS UPPER LEVEL RIDGE SLIDES EAST INTO THE
ATLANTIC. RAINFALL WILL BECOME MORE WIDESPREAD THROUGH THE DAY
MONDAY AS A FRONTAL SYSTEM WITH A GOOD SOUTHERLY FETCH SHIFTS EAST.
WITH TEMPERATURES REMAINING WARM DURING THIS TIME PERIOD WILL NEED
TO WATCH THE FRONT CLOSELY FOR HYDRO CONCERNS. SO FAR MODELS ARE
SHIFTING IT EAST QUICKLY ENOUGH TO KEEP PRECIPITATION AMOUNTS IN THE
INCH RANGE BUT IF WAVES END UP FORMING ALONG THE FRONTAL BOUNDARY
AND IT STALLS...THE NORTH TO SOUTH ORIENTATION OF THE SYSTEM WOULD
BE FAVORABLE FOR PICKING A GOOD BIT MORE RAIN. AGAIN AT MOMENT IT
DOES NOT LOOK LIKE THE FRONT WILL STALL BUT RATHER JUST SOMETHING TO
WATCH. COOLER AIR WILL SWING DOWN BEHIND THE FRONTAL MIDWEEK BUT
LOOKS FAR ENOUGH BEHIND THAT MOST OF THE LINGERING POST FRONTAL
SHOWERS WILL BE OVER WITH BY THEN.
&&
.AVIATION /20Z THURSDAY THROUGH TUESDAY/...
LOW LEVEL MOISTURE WILL BE PERSISTENT INTO TONIGHT...AND CONTINUE
TO HANG ON IN THE MOUNTAINS THROUGH THE TAF PERIOD. THIS WILL LEAD
TO PRIMARILY MVFR CEILINGS AREA WIDE...WITH BRIEF VFR POSSIBLE
THIS AFTERNOON FOR THE LOWLAND TERMINALS. CEILINGS TO LOWER A
LITTLE BIT TONIGHT...AND WILL FLIRT WITH IFR ONCE AGAIN. BKW TO
CONTINUE WITH LIFR CONDITIONS THROUGH THIS EVENING.
NORTHWEST FLOW TO 10KTS...WITH THE OCCASIONAL GUST TO
15KTS...LIKELY THROUGH FRIDAY.
FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 18Z FRIDAY...
FORECAST CONFIDENCE...MEDIUM TO HIGH.
ALTERNATE SCENARIOS: MAY NEED MORE IFR TONIGHT FROM LOWER
CEILINGS. TIME OF LOW LEVEL MOISTURE EXIT AND CLOUD BREAK UP COULD
VARY INTO TONIGHT AND FRIDAY.
EXPERIMENTAL TABLE OF FLIGHT CATEGORY OBJECTIVELY SHOWS CONSISTENCY
OF WFO FORECAST TO AVAILABLE MODEL INFORMATION:
H = HIGH: TAF CONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL.
M = MEDIUM: TAF HAS VARYING LEVEL OF CONSISTENCY WITH MODELS.
L = LOW: TAF INCONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL.
UTC 1HRLY 20 21 22 23 00 01 02 03 04 05 06 07
EST 1HRLY 15 16 17 18 19 20 21 22 23 00 01 02
CRW CONSISTENCY H H H H H M M M H M L L
HTS CONSISTENCY H H H H M M M M M H M M
BKW CONSISTENCY L L H H M H M M M L L L
EKN CONSISTENCY L L L L L L L L L L L L
PKB CONSISTENCY H H H H H H H H M M H H
CKB CONSISTENCY H H H H M M M M M H H L
AFTER 18Z FRIDAY...
NO WIDESPREAD IFR EXPECTED.
&&
.RLX WATCHES/WARNINGS/ADVISORIES...
WV...NONE.
OH...NONE.
KY...NONE.
VA...NONE.
&&
$$
SYNOPSIS...MZ/26/JR
NEAR TERM...26
SHORT TERM...MZ
LONG TERM...JR
AVIATION...26
AREA FORECAST DISCUSSION
NWS PORTLAND OR
850 PM PST WED MAR 6 2013
.SYNOPSIS...LOW PRESSURE ESSENTIALLY STALLED OVER THE PACIFIC
NORTHWEST WILL LINGER AND WEAKEN THROUGH THURSDAY. THIS WILL KEEP THE
WEATHER UNSETTLED WITH LIGHT TO MODERATE RAIN AT TIMES THROUGH
THURSDAY. SNOW LEVELS WILL HOVER AROUND 2500 FT THROUGH THURSDAY
NIGHT...THOUGH HEAVIER SHOWERS MAY TEMPORARILY LOWER THE SNOW LEVEL
AT TIMES. THIS SYSTEM WILL SLOWLY MOVE EAST INTO THE ROCKIES...
ALLOWING AN UPPER RIDGE TO BUILD IN FOR WARMER AND DRIER WEATHER
FRIDAY AND POSSIBLY THROUGH THE WEEKEND.
&&
.SHORT TERM...A BROAD UPPER LEVEL TROUGH JUST OFF THE OREGON COAST
CONTINUES TO PRODUCE AN UNSETTLED AND MESSY PATTERN ACROSS THE
PACIFIC NORTHWEST. THE MAIN UPPER LEVEL LOW SPINNING OFF THE SOUTH
OREGON COAST WILL CONTINUE TO DROP SOUTHWARD PLACING MUCH OF WESTERN
OREGON UNDER DEEP SOUTHWESTERLY FLOW. A DEFORMATION AXIS
EXTENDING NORTHEASTWARD FROM THIS LOW PRESSURE TO THE MOUTH OF THE
COLUMBIA RIVER AND PORTIONS OF SOUTHWEST WASHINGTON IS CURRENTLY
PRODUCING STEADIER PRECIPITATION ACROSS PACIFIC COUNTY AND PRIMARILY
POINTS NOW NORTH OF OUR CWA. THE GFS AND EC GENERALLY AGREE THIS
DEFORMATION AXIS SHOULD GRADUALLY WEAKEN NEAR ITS CURRENT LOCATION
OVER THE NEXT 12 HOURS. MEANWHILE...THE NAM ACTUALLY MOVES THIS
BOUNDARY BACK TOWARDS THE SOUTHEAST OVERNIGHT TOWARDS
PORTLAND...ALBEIT THE LATEST MODEL RUN HAS TRENDED TOWARDS THE GLOBAL
MODELS. AS A RESULT...POPS WERE HEDGED HIGHEST TOWARDS ASTORIA AND
THE WILLAPA HILLS OVERNIGHT INTO THURSDAY MORNING AS THIS FEATURE
DECAYS IN PLACE.
MEANWHILE...A RELATIVELY MOIST AND UNSTABLE AIRMASS IS PRODUCING
ISOLATED TO SCATTERED SHOWERS OVER THE WILLAMETTE VALLEY THIS
EVENING. OROGRAPHIC ASCENT INTO THE SOUTH WASHINGTON CASCADES HAS
BEEN QUITE PRONOUNCED IN THE SOUTHWESTERLY FLOW AS SHOWERS CONTINUE
TO DEVELOP RAPIDLY IN THE FOOTHILLS NORTHEAST OF VANCOUVER. MANY
SITES ACROSS THE SOUTH WASHINGTON CASCADES HAVE ALREADY REACHED
WINTER WX ADVISORY CRITERIA AND THE MODELS GENERALLY AGREE DECENT
OROGRAPHICS WILL CONTINUE THROUGH ABOUT 12Z TONIGHT. AS A
RESULT...WE WENT AHEAD AND ISSUED A WINTER WX ADVISORY. UPON FURTHER
INSPECTION...RADAR RETURNS HAVE LET UP AT LEAST A BIT IN THE LAST
HOUR. THIS IS LIKELY IN RESPONSE TO THE BEST OMEGA BECOMING
INCREASINGLY CONFINED TO BELOW THE DENDRITIC LAYER AS SEEN IN THE
LATEST NAM AND RUC CROSS SECTIONS. AS A RESULT...CONFIDENCE IS LOW
THAT ANOTHER 6 INCHES WILL FALL TONIGHT...BUT WILL KEEP THE ADVISORY
GOING FOR NOW.
ALSO WENT AHEAD AND REMOVED THE MENTION OF THUNDER FROM THE CENTRAL
OREGON COAST AS CONVECTION HAS REMAINED TOO SHALLOW TO PRODUCE ENOUGH
CHARGE SEPARATION TO GENERATE LIGHTNING. /NEUMAN
PREVIOUS DISCUSSION BELOW...BELIEVE MODELS ARE A LITTLE OVERDONE ON
CLOUD COVER THURSDAY...BUT NONETHELESS IT SHOULD BE A MOSTLY CLOUDY
DAY WITH PLENTY OF STRATOCUMULUS. THERE PROBABLY WILL BE ENOUGH SUN
BREAKS TO GENERATE ENOUGH SHALLOW INSTABILITY FOR MORE SHOWERS
THURSDAY...ESPECIALLY OVER THE HIGHER TERRAIN. WITH FREEZING LEVELS
LOW...THE MORE VIGOROUS SHOWERS COULD PRODUCE SMALL HAIL. HOWEVER
THESE SHOWERS SHOULD BE CAPPED AROUND 10-12 KFT...WHICH SHOULD LIMIT
THE THREAT FOR THUNDER.
CLEARING TREND BEGINS IN EARNEST THU NIGHT...WITH A CHILLY NIGHT
EXPECTED FOR THE VALLEYS. AFTER STARTING OFF WITH SOME PATCHES OF
FOG...FRIDAY WILL BE PARTLY TO MOSTLY SUNNY ASIDE FROM SOME MOUNTAIN
CLOUDS AND ISOLATED SHOWERS. UPPER LEVEL RIDGING BUILDS FRI NIGHT AND
SATURDAY...WITH MORE NIGHT/MORNING FOG POSSIBLE. SINCE THIS RIDGE IS
RATHER FLAT...THERE COULD BE SOME HIGH CLOUDS ESPECIALLY IN THE
NORTHERN ZONES...OTHERWISE MILD AND SUNNY CONDITIONS EXPECTED FOR
SATURDAY. WEAGLE
.LONG TERM...SATURDAY EVENING THROUGH TUESDAY...A BREAK IN THE
WEATHER IS EXPECTED FOR THE WEEKEND AS A FLAT UPPER LEVEL RIDGE
BUILDS OVER THE AREA. MODELS AGREE ON KEEPING ANY SYSTEMS TO THE
NORTH THROUGH SUNDAY...THOUGH WITH THE FLAT RIDGE OVER THE AREA AND
WESTERLY FLOW ALOFT BRINGING MOISTURE INTO WASHINGTON...THE
PRECIPITATION IS NEVER VERY DISTANT FROM OUR AREA. CURRENTLY MODELS
AGREE ON LIMITING PRECIPITATION GENERALLY TO WASHINGTON. SOUTHWEST
WASHINGTON ISNT LIKELY TO SEE MUCH PRECIPITATION UNLESS THE JET
STREAM SLIPS SOUTHWARD A BIT. MODEL CONSENSUS IS TO DROP THE RIDGE
SOUTH BY LATE TUESDAY AND BRING A CHANCE OF RAIN TO THE AREA. A
STRONGER TROUGH FOLLOWS SOMETIME NEAR THE END OF THE WEEK. KWELSON
&&
.AVIATION...THE STEADY RAIN HAS MOVED NORTH INTO WESTERN WASHINGTON
WITH SCATTERED SHOWERS NOW STREAMING INTO NW OREGON. COASTAL
AREAS LIKELY TO REMAIN IN MVFR CIGS TONIGHT AND THU MORNING BUT
MODEL TRENDS INDICATE LOW VFR IS LIKELY THU AFTERNOON. INLAND
AREAS SHOULD REMAIN VFR THROUGH 10Z THU THEN MVFR WITH CIGS
AROUND 2000 TO 2500 FT BECOMING MORE COMMON. BUT THAT SHOULD LAST
THROUGH ABOUT 17Z TO 20Z THU. THE COAST RANGE AND CASCADES WILL BE
FREQUENTLY OBSCURED THROUGH AROUND 06Z THU...WITH THE S WA
CASCADES AND FAR N OREGON CASCADES OBSCURED THROUGH AT LEAST 18Z
THU.
KPDX AND APPROACHES...PREDOMINANT VFR EXPECTED THROUGH ABOUT 10Z.
MOIST BOUNDARY LAYER AND INCREASING STABILITY OVERNIGHT SHOULD
LEAD TO MVFR CIGS AROUND 10Z AND CONTINUING UNTIL 18Z THU OR
SO. VFR EXPECTED AFTER THAT AND LIKELY CONTINUING THROUGH 06Z FRI.
&&
.MARINE...SURFACE TROUGH LAY NORTH TO SOUTH ACROSS THE WATERS
TONIGHT. A SMALL SURFACE LOW OFF THE SOUTH COAST IS BRINGING
ADVISORY WINDS TO THE CENTRAL COASTAL WATERS. MODELS ARE IN SOME
DISAGREEMENT WITH THE EVOLUTION OF THE TROUGH AND LOW OVERNIGHT
INTO THU MORNING. FOR NOW WILL KEEP THE ADVISORY FOR WINDS THROUGH
7 AM THU...BUT IT COULD LAST A LITTLE LONGER.
SEAS WILL HOVER IN THE 5 TO 7 FOOT RANGE THROUGH FRI NIGHT.
HOWEVER SEAS WILL BE CLOSE TO 10 FT OVER THE CENTRAL WATERS MAINLY
DUE TO SHORTER PERIOD WIND WAVES. LATEST MODEL GUIDANCE SHOWS A
SET OF LONGER-PERIOD SEAS REACHING THE WATERS SATURDAY...BUT NOT
QUITE UP TO 10 FT.
&&
.PQR WATCHES/WARNINGS/ADVISORIES...
OR...NONE.
WA...WINTER WEATHER ADVISORY UNTIL 4 AM PST THURSDAY FOR SOUTH
WASHINGTON CASCADES.
PZ...SMALL CRAFT ADVISORY FOR WINDS UNTIL 7 AM PST THURSDAY FOR
COASTAL WATERS FROM CASCADE HEAD OR TO FLORENCE OR OUT 60 NM.
&&
$$
MORE WEATHER INFORMATION ONLINE AT...HTTP://WEATHER.GOV/PORTLAND
THIS DISCUSSION IS FOR NORTHWEST OREGON AND SOUTHWEST WASHINGTON
FROM THE CASCADE CREST TO 60 NAUTICAL MILES OFFSHORE. THE AREA IS
COMMONLY REFERRED TO AS THE FORECAST AREA.
AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NWS RAPID CITY SD
1042 AM MST THU MAR 7 2013
.UPDATE...
ISSUED AT 830 AM MST THU MAR 7 2013
15Z SURFACE ANALYSIS HAD WEAK LOW OVER NORTHEAST WY WITH GENTLE
COOL FRONT/TROUGH FROM CENTRAL MT INTO SOUTHWEST SD. MID/HIGH
CLOUDS STREAMING OVER CWA ON 90KT UPPER LEVEL JET...BUT THEY ARE
PARTIALLY TRANSPARENT. 12Z RAP MESHES WELL WITH CURRENT TRENDS.
WILL TWEAK TEMPERATURES WEST OF THE FRONT A COUPLE OF DEGREES UP
BASED ON 12Z RAP/KUNR SOUNDING...AND EAST OF THE FRONT A TAD LOWER
GIVEN UPSTREAM SURFACE TRAJECTORIES. REST OF FORECAST IN GOOD
SHAPE.
&&
.SHORT TERM...(TODAY THROUGH FRIDAY NIGHT)
ISSUED AT 305 AM MST THU MAR 7 2013
WESTERN CONUS TROUGHING CONTINUES...SUPPORTING FAST
DISTURBED OVER THE LOCAL REGION. ASSOCIATED ADVECTING IMPULSE
CONTINUES TO PROPAGATE ENE ACROSS THE NORTHERN PLAINS...WITH AN
ASSOCIATED LL TROUGH REFLECTION. THIS IMPULSE WILL CONTINUE EAST
TODAY...SUPPORTING WEAK CAA IN IT/S WAKE. FLOW WILL QUICKLY RESPOND
TO THE NEXT ADVANCING SHORTWAVE TOUGH AS THE MAIN WESTERN CONUS
LONG WAVE TROUGH CONTINUES TO DIG SOUTH INTO THE SW CONUS. WAA WILL
AGAIN SPREAD OVER THE REGION FRIDAY AHEAD OF THE NEXT ADVANCING
DISTURBANCE...WITH LL FLOW RESPONDING TO ONGOING PRESSURE FALLS.
WEAK DEFORMATION ZONE WILL DEVELOP OVER PORTIONS OF NE WY AND
MT...AND EAST INTO NORTH DAKOTA....POSSIBLY SUPPORTING SOME LIGHT
PRECIP ACTIVITY LATE FRIDAY MORNING INTO FRIDAY AFTERNOON THERE.
LATEST GUIDANCE CONTINUES TO TREND THIS AREA OF LIFT NW...WITH ONLY
LOW TO MID RANGE CHANCE POPS RETAINED OVER THE NW FA.
OTHERWISE...ATTENTION TURNS TOWARD INCREASING LARGE SCALE ASCENT
WITH THE AFOREMENTIONED LEAD SHORTWAVE TROUGH. INCREASING LL
MOISTURE PER SE LL FLOW WILL SUPPORT SUFFICIENT LL MOISTURE FLUX FOR
RAIN/SNOW/WITH THE POTENTIAL FOR FREEZING RAIN REMAINING OVER
SCENTRAL SD INTO CENTRAL SD...GIVEN A STRONG ELEVATED WARM TONGUE
ADVANCING NW AHEAD OF THIS WAVE. MEANWHILE...AN EXPECTED NORTHERN
STREAM TROUGH WILL QUICKLY ADVECT INTO THE NORTHERN PLAINS LATER
FRIDAY NIGHT...SUPPORTING INCREASING LL CAA AND INDUCED LL PRESSURE
FALLS. THIS WAVE AND ASSOCIATED COLD FRONT WILL INTRODUCE ENOUGH
COLD AIR TO END ALL MIXED PRECIP CHANCES SAT MORNING...WITH SNOW
BEING THE DOMINANT PRECIP TYPE ALL PLACES AS THE MAIN SW CONUS UPPER
TROUGH BEGINS TO EJECT TOWARD THE REGION.
FORECAST MODELS ARE STILL WAVERING ON THE EXACT DETAILS PER THIS
EVOLUTION...WITH STILL MANY DETAILS TO BE WORKED OUT.
HOWEVER...CONFIDENCE HAS INCREASED THAT THERE WILL BE A PERIOD OF
MIXED PRECIP IN SCENTRAL SD FRIDAY NIGHT. STRONG WARM NOSE /2-3C/ IN
A THETA-E ADV REGIME WITH INCREASING LSA WILL BE MORE THAN AMPLE
TO SUPPORT PRECIP DEVELOPMENT. FORECAST MODELS SUGGEST UP TO A
QUARTER INCH QPF IN FAR SCENTRAL SD...MAINLY RAIN AT FIRST WITH A
PERIOD OF ICING LIKELY LATER /WHICH IS IN LINE WITH CURRENT SREF
PROGS/. ATTM IT DOES NOT APPEAR TO THAT SIG ICING IS EXPECTED
GIVEN A RATHER WARM BL THROUGH FRI NIGHT. HOWEVER...SOME SOLUTIONS
SUGGEST UP TO A TENTH OF INCH OF ICE ACCUMS IS POSSIBLE ESP AROUND
THE WINNER AREA. THIS WILL NEED TO BE WATCHED.
SMALL ADJUSTMENT MADE TO HIGH TEMPS...WHICH WILL BE TRICKY TODAY
GIVEN THE ADVANCING COLD FRONT AND ASSOCIATED CAA TIMING. STILL
EXPECT 50S AND SOME LOWER 60S WILL BE POSSIBLE IN SW SD...WITH TEMPS
ONLY REACHING THE 40S OVER NW SD AND NE WY. COOLER TEMPS EXPECTED
FRI.
.LONG TERM...(SATURDAY THROUGH WEDNESDAY)
ISSUED AT 305 AM MST THU MAR 7 2013
LARGE UPPER LEVEL TROF WILL CROSS THE NORTHERN PLAINS THIS WEEKEND
WITH A RIDGE BUILDING IN FOR EARLY NEXT WEEK. POTENT SYSTEM WITHIN
THE TROF WILL CROSS THE CENTRAL PLAINS ON SATURDAY AND SUNDAY...WITH
THE NORTHERN EDGE OF THE SYSTEM BRINGING ACCUMULATING SNOWS TO
SOUTHERN PORTIONS OF THE FORECAST AREA.
LATEST MODEL RUNS CONTINUE TO SHOW UPPER LOW SWINGING THROUGH THE
FOUR CORNERS AREA VERY EARLY SATURDAY MORNING...AND TRACKING
EAST-NORTHEASTWARD THROUGH THE WEEKEND. MID LEVEL LOW DEVELOPS
ACROSS EASTERN COLORADO BY MIDDAY SATURDAY AS NORTHERN EDGE OF
PRECIP SHIELD SHIFTS NORTH INTO THE AREA. AMPLE MOISTURE AND
NORTHERLY BOUNDARY LAYER FLOW WILL ALSO BRING UPSLOPE SNOW TO THE
NORTHERN BLACK HILLS AREA SATURDAY AND SATURDAY EVENING. SYSTEM
QUICKLY SHIFTS EAST SATURDAY NIGHT...WITH SNOW TAPERING OFF BY EARLY
SUNDAY MORNING.
THE BEST CHANCES FOR SIGNIFICANT PCPN AMOUNTS WILL BE ACROSS FAR
SOUTHERN SD...ESPECIALLY SOUTH CENTRAL SD...AND ACROSS THE NORTHERN
BLACK HILLS. UP TO 6 INCHES OF SNOWFALL WILL BE POSSIBLE IN THESE
AREAS.
BEYOND THAT...TEMPERATURES WILL GRADUALLY WARM INTO EARLY NEXT WEEK
AS RIDGE BUILDS OVER THE WESTERN CONUS. MOSTLY DRY WEATHER IS
EXPECTED ACROSS THE AREA...BUT WILL KEEP SOME LOW CHANCES FOR RAIN
AND SNOW SHOWERS FOR MONDAY AFTERNOON INTO TUESDAY ACROSS PORTIONS
OF NORTHEASTERN WY AND INTO THE BLACK HILLS AS WEAK UPPER LEVEL
ENERGY PASSES OVER THE RIDGE.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z FRIDAY AFTERNOON)
ISSUED AT 1041 AM MST THU MAR 7 2013
VFR CONDITIONS ARE GENERALLY EXPECTED THROUGH FRIDAY MORNING. THERE
IS A CHANCE FOR SNOW SHOWERS LATE TONIGHT AND FRIDAY MORNING ACROSS
FAR NORTHEASTERN WY INTO FAR NORTHWESTERN SD...WITH LOCAL MVFR
CONDITIONS EXPECTED.
&&
.UNR WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
WY...NONE.
&&
$$
UPDATE...HELGESON
SHORT TERM...JC
LONG TERM...15
AVIATION...26
AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NWS RAPID CITY SD
834 AM MST THU MAR 7 2013
.UPDATE...
ISSUED AT 830 AM MST THU MAR 7 2013
15Z SURFACE ANALYSIS HAD WEAK LOW OVER NORTHEAST WY WITH GENTLE
COOL FRONT/TROUGH FROM CENTRAL MT INTO SOUTHWEST SD. MID/HIGH
CLOUDS STREAMING OVER CWA ON 90KT UPPER LEVEL JET...BUT THEY ARE
PARTIALLY TRANSPARENT. 12Z RAP MESHES WELL WITH CURRENT TRENDS.
WILL TWEAK TEMPERATURES WEST OF THE FRONT A COUPLE OF DEGREES UP
BASED ON 12Z RAP/KUNR SOUNDING...AND EAST OF THE FRONT A TAD LOWER
GIVEN UPSTREAM SURFACE TRAJECTORIES. REST OF FORECAST IN GOOD
SHAPE.
&&
.SHORT TERM...(TODAY THROUGH FRIDAY NIGHT)
ISSUED AT 305 AM MST THU MAR 7 2013
WESTERN CONUS TROUGHING CONTINUES...SUPPORTING FAST
DISTURBED OVER THE LOCAL REGION. ASSOCIATED ADVECTING IMPULSE
CONTINUES TO PROPAGATE ENE ACROSS THE NORTHERN PLAINS...WITH AN
ASSOCIATED LL TROUGH REFLECTION. THIS IMPULSE WILL CONTINUE EAST
TODAY...SUPPORTING WEAK CAA IN IT/S WAKE. FLOW WILL QUICKLY RESPOND
TO THE NEXT ADVANCING SHORTWAVE TOUGH AS THE MAIN WESTERN CONUS
LONG WAVE TROUGH CONTINUES TO DIG SOUTH INTO THE SW CONUS. WAA WILL
AGAIN SPREAD OVER THE REGION FRIDAY AHEAD OF THE NEXT ADVANCING
DISTURBANCE...WITH LL FLOW RESPONDING TO ONGOING PRESSURE FALLS.
WEAK DEFORMATION ZONE WILL DEVELOP OVER PORTIONS OF NE WY AND
MT...AND EAST INTO NORTH DAKOTA....POSSIBLY SUPPORTING SOME LIGHT
PRECIP ACTIVITY LATE FRIDAY MORNING INTO FRIDAY AFTERNOON THERE.
LATEST GUIDANCE CONTINUES TO TREND THIS AREA OF LIFT NW...WITH ONLY
LOW TO MID RANGE CHANCE POPS RETAINED OVER THE NW FA.
OTHERWISE...ATTENTION TURNS TOWARD INCREASING LARGE SCALE ASCENT
WITH THE AFOREMENTIONED LEAD SHORTWAVE TROUGH. INCREASING LL
MOISTURE PER SE LL FLOW WILL SUPPORT SUFFICIENT LL MOISTURE FLUX FOR
RAIN/SNOW/WITH THE POTENTIAL FOR FREEZING RAIN REMAINING OVER
SCENTRAL SD INTO CENTRAL SD...GIVEN A STRONG ELEVATED WARM TONGUE
ADVANCING NW AHEAD OF THIS WAVE. MEANWHILE...AN EXPECTED NORTHERN
STREAM TROUGH WILL QUICKLY ADVECT INTO THE NORTHERN PLAINS LATER
FRIDAY NIGHT...SUPPORTING INCREASING LL CAA AND INDUCED LL PRESSURE
FALLS. THIS WAVE AND ASSOCIATED COLD FRONT WILL INTRODUCE ENOUGH
COLD AIR TO END ALL MIXED PRECIP CHANCES SAT MORNING...WITH SNOW
BEING THE DOMINANT PRECIP TYPE ALL PLACES AS THE MAIN SW CONUS UPPER
TROUGH BEGINS TO EJECT TOWARD THE REGION.
FORECAST MODELS ARE STILL WAVERING ON THE EXACT DETAILS PER THIS
EVOLUTION...WITH STILL MANY DETAILS TO BE WORKED OUT.
HOWEVER...CONFIDENCE HAS INCREASED THAT THERE WILL BE A PERIOD OF
MIXED PRECIP IN SCENTRAL SD FRIDAY NIGHT. STRONG WARM NOSE /2-3C/ IN
A THETA-E ADV REGIME WITH INCREASING LSA WILL BE MORE THAN AMPLE
TO SUPPORT PRECIP DEVELOPMENT. FORECAST MODELS SUGGEST UP TO A
QUARTER INCH QPF IN FAR SCENTRAL SD...MAINLY RAIN AT FIRST WITH A
PERIOD OF ICING LIKELY LATER /WHICH IS IN LINE WITH CURRENT SREF
PROGS/. ATTM IT DOES NOT APPEAR TO THAT SIG ICING IS EXPECTED
GIVEN A RATHER WARM BL THROUGH FRI NIGHT. HOWEVER...SOME SOLUTIONS
SUGGEST UP TO A TENTH OF INCH OF ICE ACCUMS IS POSSIBLE ESP AROUND
THE WINNER AREA. THIS WILL NEED TO BE WATCHED.
SMALL ADJUSTMENT MADE TO HIGH TEMPS...WHICH WILL BE TRICKY TODAY
GIVEN THE ADVANCING COLD FRONT AND ASSOCIATED CAA TIMING. STILL
EXPECT 50S AND SOME LOWER 60S WILL BE POSSIBLE IN SW SD...WITH TEMPS
ONLY REACHING THE 40S OVER NW SD AND NE WY. COOLER TEMPS EXPECTED
FRI.
.LONG TERM...(SATURDAY THROUGH WEDNESDAY)
ISSUED AT 305 AM MST THU MAR 7 2013
LARGE UPPER LEVEL TROF WILL CROSS THE NORTHERN PLAINS THIS WEEKEND
WITH A RIDGE BUILDING IN FOR EARLY NEXT WEEK. POTENT SYSTEM WITHIN
THE TROF WILL CROSS THE CENTRAL PLAINS ON SATURDAY AND SUNDAY...WITH
THE NORTHERN EDGE OF THE SYSTEM BRINGING ACCUMULATING SNOWS TO
SOUTHERN PORTIONS OF THE FORECAST AREA.
LATEST MODEL RUNS CONTINUE TO SHOW UPPER LOW SWINGING THROUGH THE
FOUR CORNERS AREA VERY EARLY SATURDAY MORNING...AND TRACKING
EAST-NORTHEASTWARD THROUGH THE WEEKEND. MID LEVEL LOW DEVELOPS
ACROSS EASTERN COLORADO BY MIDDAY SATURDAY AS NORTHERN EDGE OF
PRECIP SHIELD SHIFTS NORTH INTO THE AREA. AMPLE MOISTURE AND
NORTHERLY BOUNDARY LAYER FLOW WILL ALSO BRING UPSLOPE SNOW TO THE
NORTHERN BLACK HILLS AREA SATURDAY AND SATURDAY EVENING. SYSTEM
QUICKLY SHIFTS EAST SATURDAY NIGHT...WITH SNOW TAPERING OFF BY EARLY
SUNDAY MORNING.
THE BEST CHANCES FOR SIGNIFICANT PCPN AMOUNTS WILL BE ACROSS FAR
SOUTHERN SD...ESPECIALLY SOUTH CENTRAL SD...AND ACROSS THE NORTHERN
BLACK HILLS. UP TO 6 INCHES OF SNOWFALL WILL BE POSSIBLE IN THESE
AREAS.
BEYOND THAT...TEMPERATURES WILL GRADUALLY WARM INTO EARLY NEXT WEEK
AS RIDGE BUILDS OVER THE WESTERN CONUS. MOSTLY DRY WEATHER IS
EXPECTED ACROSS THE AREA...BUT WILL KEEP SOME LOW CHANCES FOR RAIN
AND SNOW SHOWERS FOR MONDAY AFTERNOON INTO TUESDAY ACROSS PORTIONS
OF NORTHEASTERN WY AND INTO THE BLACK HILLS AS WEAK UPPER LEVEL
ENERGY PASSES OVER THE RIDGE.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z FRIDAY MORNING)
ISSUED AT 305 AM MST THU MAR 7 2013
VFR CONDITIONS ARE EXPECTED THROUGH FRIDAY MORNING. THE EXCEPTION
WILL BE ACROSS PARTS OF NORTHEAST WYOMING...WHERE SOME LIGHT SNOW
SHOWERS WILL BE POSSIBLE AFTER MIDNIGHT.
&&
.UNR WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
WY...NONE.
&&
$$
UPDATE...HELGESON
SHORT TERM...JC
LONG TERM...15
AVIATION...15
AREA FORECAST DISCUSSION
NWS NASHVILLE TN
1152 AM CST THU MAR 7 2013
.UPDATE...FOR 18Z TAFS.
&&
.AVIATION...
MVFR STRATUS DECK CONTINUES TO LINGER ACROSS THE FORECAST AREA.
CLEARING SHOWING UP ON VISIBILE SATELLITE IN SOUTHERN COUNTIES.
LOOK FOR CLEARING SKIES TO CONTINUE THROUGH 00Z. WITH LOW LEVEL
MOISTURE NOT MIXING OUT LOOK FOR SCT CU AT ALL TERMINALS THIS
AFTERNOON. LATE TONIGHT MVFR CONDITIONS WILL REAPPEAR FOR BNA AND
CKV AROUND 06Z. MVFR TO IFR CONDITIONS WILL TAKE PLACE AROUND CSV.
72/MD
&&
.PREV DISCUSSION... /ISSUED 1124 AM CST THU MAR 7 2013/
UPDATE...
LOW LEVEL MOISTURE IS PREVENTING TEMPERATURES FROM RISING THIS
MORNING AS PREVIOUSLY FORECAST. NEWEST RUC AND HRRR INDICATE THIS
CLOUD COVER SHOULD ERODE OVER THE NEXT FEW HOURS AND TEMPERATURES
WILL BEGIN TO RISE MORE RAPIDLY AT THAT POINT. HAVE LOWERED HIGHS
A FEW DEGREES BASED OFF THIS SKY TREND AND EDITED SKY GRIDS TO
REFLECT THE LATEST RUC DEPICTION.
PREV DISCUSSION... /ISSUED 526 AM CST THU MAR 7 2013/
UPDATE...FOR 12Z AVIATION FORECAST
AVIATION...
LOW DECK REMAINS ACROSS MUCH OF MID STATE EXCEPT FOR SOUTHWEST
CORNER. SHORT RANGE MODELS BEGIN ERODING LOW DECK FROM SOUTHWEST
AFTER 12Z. I HAVE CLARKSVILLE SCATTERED AT 25 HNDRD BY 15Z WITH
NASHVILLE GOING SCATTERED AT SAME LEVEL AROUND 16Z. NOT REAL
OPTIMISTIC ABOUT CROSSVILLE SCATTERING OUT DURING THE DAY BUT
SINCE MOIST LAYER IS QUITE THIN WOULD THINK IT WOULD MIX OUT
DURING THE DAY AT SOME POINT. I WENT WITH LOW DECK SCATTERING OUT
AROUND 20Z AT CROSSVILLE.
BOYD
PREV DISCUSSION... /ISSUED 211 AM CST THU MAR 7 2013/
DISCUSSION...SURFACE HIGH PRESSURE REMAINS SITUATED WEST OF
MIDDLE TENNESSEE WITH STUBBORN LOW CLOUDS STILL COVERING MOST OF
THE MID STATE. EVENING SOUNDING FROM OHX SHOWS THE CLOUD DECK ONLY
AROUND 1400 FT THICK, SO MORNING SUN SHOULD PROVIDE ENOUGH HEAT TO
QUICKLY ERODE CLOUD COVER AND FINALLY SCATTER US OUT. AFTERWARDS,
LOOK FOR SEVERAL DAYS OF MILD, QUIET WEATHER, WITH SIGNIFICANTLY
WARMER TEMPERATURES IN STORE THIS WEEKEND. SURFACE RIDGE WILL
LIKELY SLIDE EAST OF MIDDLE TENNESSEE FRIDAY OR FRIDAY NIGHT, WITH
A SW FLOW DEVELOPING ALOFT. NEXT ACTIVE WEATHER SYSTEM WILL MOVE
IN SUNDAY NIGHT, WITH THUNDERSTORMS ON MONDAY, ALTHOUGH MIDDLE
TENNESSEE IS NOWHERE NEAR ANY SEVERE WEATHER RISK AREA THROUGH DAY
8.
&&
.OHX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
72
AREA FORECAST DISCUSSION
NWS NASHVILLE TN
1124 AM CST THU MAR 7 2013
.UPDATE...
LOW LEVEL MOISTURE IS PREVENTING TEMPERATURES FROM RISING THIS
MORNING AS PREVIOUSLY FORECAST. NEWEST RUC AND HRRR INDICATE THIS
CLOUD COVER SHOULD ERODE OVER THE NEXT FEW HOURS AND TEMPERATURES
WILL BEGIN TO RISE MORE RAPIDLY AT THAT POINT. HAVE LOWERED HIGHS
A FEW DEGREES BASED OFF THIS SKY TREND AND EDITED SKY GRIDS TO
REFLECT THE LATEST RUC DEPICTION.
&&
.PREV DISCUSSION... /ISSUED 526 AM CST THU MAR 7 2013/
UPDATE...FOR 12Z AVIATION FORECAST
AVIATION...
LOW DECK REMAINS ACROSS MUCH OF MID STATE EXCEPT FOR SOUTHWEST
CORNER. SHORT RANGE MODELS BEGIN ERODING LOW DECK FROM SOUTHWEST
AFTER 12Z. I HAVE CLARKSVILLE SCATTERED AT 25 HNDRD BY 15Z WITH
NASHVILLE GOING SCATTERED AT SAME LEVEL AROUND 16Z. NOT REAL
OPTIMISTIC ABOUT CROSSVILLE SCATTERING OUT DURING THE DAY BUT
SINCE MOIST LAYER IS QUITE THIN WOULD THINK IT WOULD MIX OUT
DURING THE DAY AT SOME POINT. I WENT WITH LOW DECK SCATTERING OUT
AROUND 20Z AT CROSSVILLE.
BOYD
PREV DISCUSSION... /ISSUED 211 AM CST THU MAR 7 2013/
DISCUSSION...SURFACE HIGH PRESSURE REMAINS SITUATED WEST OF
MIDDLE TENNESSEE WITH STUBBORN LOW CLOUDS STILL COVERING MOST OF
THE MID STATE. EVENING SOUNDING FROM OHX SHOWS THE CLOUD DECK ONLY
AROUND 1400 FT THICK, SO MORNING SUN SHOULD PROVIDE ENOUGH HEAT TO
QUICKLY ERODE CLOUD COVER AND FINALLY SCATTER US OUT. AFTERWARDS,
LOOK FOR SEVERAL DAYS OF MILD, QUIET WEATHER, WITH SIGNIFICANTLY
WARMER TEMPERATURES IN STORE THIS WEEKEND. SURFACE RIDGE WILL
LIKELY SLIDE EAST OF MIDDLE TENNESSEE FRIDAY OR FRIDAY NIGHT, WITH
A SW FLOW DEVELOPING ALOFT. NEXT ACTIVE WEATHER SYSTEM WILL MOVE
IN SUNDAY NIGHT, WITH THUNDERSTORMS ON MONDAY, ALTHOUGH MIDDLE
TENNESSEE IS NOWHERE NEAR ANY SEVERE WEATHER RISK AREA THROUGH DAY
8.
&&
.OHX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
TB12
FORECAST DISCUSSION FOR ROUTINE AFTERNOON FORECAST ISSUANCE
.SYNOPSIS...
ISSUED AT 240 PM CST THU MAR 7 2013
SEASONABLE TEMPERATURES...WITH THE NEXT CHANCE FOR
SIGNIFICANT PRECIPITATION COMING DURING THE WEEKEND.
AMPLIFIED SPLIT FLOW REGIME IN PLACE ACRS NOAM. THAT WL PERSIST
THROUGH THE WEEKND AS STG SRN STREAM TROF MIGRATES EWD ACRS THE
COUNTRY. THE TREND NEXT WK WL BE FOR THE FLOW TO BECOME MORE
CONSOLIDATED AND LOSE AMPLITUDE.
THE PATTERN WILL NOT SUPPORT ANY SIG COLD INTRUSIONS INTO THE
AREA...SO TEMPS SHOULD BE NR OR A LITTLE ABV NORMAL FOR THE MOST
PART. MAIN PCPN EVENT WL BE WITH THE CYCLONE CROSSING THE RGN THIS
WEEKEND...WITH AMNTS PROBABLY ENDING UP NR OR A LITTLE ABV NORMAL.
&&
.SHORT TERM...TONIGHT AND FRIDAY
ISSUED AT 240 PM CST THU MAR 7 2013
LOW CLDS OFF LAKE SUPERIOR PROVED TOUGH TO DISLODGE
FM NRN WI THIS MORNING. BUT MARCH SUNSHINE WAS ABLE TO HELP
MIXING WORK THROUGH THE CLOUD LAYER...WITH ONLY SCT LOW CLDS NOW
REMAINING. HIGH AND MIDDLE CLDS WERE STREAMING IN FM THE W...AND
WL BE WORKING ACRS THE AREA TNGT. SFC RIDGE WL BE RIGHT ACRS THE
AREA...SO WINDS WL BE LIGHT. COUNTING ON HIGH AND MIDDLE CLDS TO
KEEP FG FROM GETTING OUT OF HAND. CONTD WITH PREV FCST OF JUST
HAVING PATCHY FOG DEVELOPING AFTER MIDNIGHT...AND CONTG INTO FRI
MORNING. ALSO COUNTING ON CLDS KEEPING TEMPS FROM GOING INTO FREE
FALL. BLENDED THE MIN OF THE VARIOUS GUID PRODUCTS WITH THE WITH
ECMWF AND BIAS-CORRECTED ECMWF...WHICH HAVE BEEN PERFORMING WELL
LATELY. THE RESULT WAS A LOWERING OF THE MINS IN MOST AREAS BY A
FEW DEGREES.
QUIET WX WL CONT FRIDAY. TEMPS SHOULD BE A FEW DEGREES WARMER THAN
TDA.
.LONG TERM...FRIDAY NIGHT THROUGH THURSDAY
ISSUED AT 240 PM CST THU MAR 7 2013
COMPLEX WEATHER PATTERN TAKING SHAPE ACROSS THE CONUS
DURING THE EXTENDED PERIOD. ALREADY NEED TO DEAL WITH APPROACHING
NRN STREAM SHORTWAVE TROF/CDFNT FRI NGT/SAT WITH PCPN TYPE ISSUES
ONGOING. THIS WL BE FOLLOWED BY THE WEAKENING SRN STREAM UPR LOW/
SFC WAVE ON THE CDFNT LIFTING NE SUNDAY NGT/MON. THERE ARE THEN
TIMING ISSUES WITH REGARDS TO A NRN STREAM CLIPPER SYSTEM AROUND
TUE AND FINALLY THERE ARE QUESTIONS AS TO THE OVERALL ORIENTATION
OF THE MEAN FLOW BY THE MIDDLE OF NEXT WEEK. THE ONLY WEATHER
ELEMENT THAT LOOKS FAIRLY STABLE WL BE TEMPS WHICH APPEAR TO BE
CLOSE TO NORMAL.
EVEN AT THIS LATE DATE...THE MDLS DISAGREE ON WHEN TO BRING PCPN
INTO NE WI STARTING LATE FRI NGT. THE NAM IS NOW SLOWER AND THE
GFS IS NOW FASTER. THE ONLY COMMON GROUND IS THAT THE HEAVIER PCPN
WL STILL BE TO OUR WEST AND SW FRI NGT ALONG A NE EXTENDED INVERTED
SFC TROF RUNNING FROM WRN NEBRASKA TO CNTRL MN. CLOUDS WL STEADILY
THICKEN THRU THE NGT AS A 40-50 KT S-SW LOW-LEVEL JET BRINGS GULF
MOISTURE NWD INTO THE WRN GREAT LAKES. EXPECT TO SEE THE LEADING
EDGE OF PCPN TO REACH CNTRL WI TOWARD DAYBREAK AND WITH SFC TEMPS
STIL EXPECTED TO BE BELOW FREEZING...THIS LEADS TO THE POSSIBILITY
OF MIXED PCPN AS WARMER AIR ALOFT ARRIVES. FCST SOUNDINGS INDICATE
THAT N-CNTRL WI WOULD REMAIN ALL SNOW...BUT WITH TEMPS JUST ABOVE
THE SFC CREEPING ABOVE 0C...CNTRL WI MAY SEE MORE OF A SNOW/SLEET
COMBINATION.
THE INVERTED SFC TROF IS PROGGED TO REMAIN WELL TO OUR WEST ON SAT...
HOWEVER THE COMBINATION OF A LEAD SHORTWAVE EJECTED NEWD FROM THE SRN
ROCKIES UPR LOW AND STRONG ISEN LIFT...WL BRING PCPN TO ALL OF NE WI.
PCPN TYPE REMAINS THE BIGGEST FCST CHALLENGE AS SFC TEMPS STRUGGLE TO
GET ABOVE THE FREEZING MARK SAT MORNING. SOUNDINGS CONT TO SHOW A
WARM LAYER JUST SLIGHTLY ABOVE 0C WHICH WOULD INDICATE A MIXED PCPN
POTENTIAL FOR ALL BUT THE LAKESHORE WHERE SE WINDS TO KEEP ANY PCPN
MORE RAIN. BY SAT AFTERNOON...CNTRL/E-CNTRL WI WARM UP SUFFICIENTLY
ENUF TO BRING MAINLY RAIN TO THIS PART OF THE FCST AREA. NRN WI
SHOULD SEE MORE OF A RAIN/SNOW MIX IN THE AFTERNOON AS SFC TEMPS GET
FAR ENUF ABOVE FREEZING.
AS THE ENTIRE SYSTEM SHIFTS EAST SAT NGT...THE INVERTED TROF BECOMES
MORE OF A CDFNT AND DRIVES EWD REACHING CNTRL WI BY 12Z SUNDAY.
VARIETY OF PCPN WL CONT OVER NE WI WITH RAIN OVER E-CNTRL WI...RAIN
BEGINNING TO MIX WITH SNOW LATE CNTRL/FAR NE WI AND A MIX CHANGING
TO ALL SNOW IN N-CNTRL WI. UP TO A COUPLE INCHES OF WET SNOW CANNOT
BE RULED OUT IN THE NORTH...OTHERWISE FOG MAY BECOME A BIGGER ISSUE
DUE TO SNOWMELT AND LIGHT WINDS IN THE VICINITY OF THE CDFNT. THE
CDFNT TO COMPLETE ITS PASSAGE THRU ERN WI SUNDAY MORNING...TO BE
FOLLOWED BY THE PASSAGE OF THE SHORTWAVE TROF SUNDAY AFTERNOON.
BETTER FORCING/LIFT TO ACCOMPANY THE CDFNT...THUS EXPECT HIGHER POPS
WOULD BE NECESSARY DURING THE MORNING HOURS. DESPITE COOLER AIR
CONTINUING TO FILTER INTO WI BEHIND THE FNT...THE MILD START TO THE
DAY MAY STILL ALLOW FOR PCPN TO REMAIN ALL RAIN OVER E-CNTRL AND
PARTS OF CNTRL WI SUNDAY AFTERNOON. THE NORTH SHOULD REMAIN ALL SNOW
AND WOULD NOT BE SURPRISED TO SEE AN ADDITIONAL LIGHT ACCUMULATION
OF SNOW. DO NOT ANTICIPATE MUCH OF A DIURNAL RISE IN TEMPS AS CAA
TAKES OVER THRU THE DAY. PERHAPS A 3 TO 5 DEG RISE FROM MORNING LOWS
IS ABOUT ALL WE WL ABLE TO MUSTER.
IT NOW APPEARS THAT THE SRN STREAM WEAKENING UPR LOW/SFC WAVE ON THE
OLD CDFNT WL PASS FAR ENUF TO OUR SE AS TO NOT HAVE ANY INFLUENCE ON
OUR WEATHER. INSTEAD...A RDG OF HI PRES IS FCST TO BUILD INTO THE WRN
GREAT LAKES SUNDAY NGT AND END THE GENERAL PCPN THREAT OVER NE WI.
NORTH WINDS COULD BRING A FEW FLURRIES ACROSS THE MI BORDER SUNDAY
NGT INTO MON...BUT EXPECT PARTLY CLOUDY SKIES TO PREVAIL WITH TEMPS
TO BE SLIGHTLY BELOW NORMAL. MDLS CONT TO HAVE DIFFERENT IDEAS ON THE
HANDLING OF A NRN STREAM CLIPPER-TYPE SYSTEM NEXT WEEK. THE ECWMF/
UKMET/GEM ARE FASTER/WEAKER WITH THE ASSOCIATED SFC LOW...WHILE THE
GFS IS SLOWER/STRONGER. AT THIS POINT...EITHER SOLUTION COULD END UP
BEING CORRECT...THUS HAVE TAKEN A DIPLOMATIC APPROACH (ESSENTIALLY
SPLITTING THE DIFFERENCE) WHICH ENDED UP BRINGING A SMALL CHC OF SNOW
INTO N-CNTRL WI MON NGT AND THEN A GENERAL CHC POP AREA-WIDE ON TUE.
LINGERING ISOLATED SNOW SHWRS OR FLURRIES ARE POSSIBLE TUE NGT...BUT
ANOTHER RDG OF HI PRES SHOULD BRING QUIET CONDITIONS ON WED. THE MAIN
FCST PROBLEM FOR THE MIDDLE OF NEXT WEEK WL BE THE ORIENTATION OF THE
MEAN FLOW AS THE ECMWF ADVERTISES A DEEPER ERN CONUS UPR TROF THAN
THE GFS. THIS DIFFERENCE WL BE KEY TO THE TIMING OF THE NEXT PACIFIC
SYSTEM WHICH WOULD ARRIVE WED NGT/THU (GFS) VERSUS THU NGT (ECWMF).
GENERAL CONSENSUS WOULD FAVOR THE ECMWF...THUS HAVE LEANED TOWARD
A DRY THU AS WELL.
&&
.AVIATION...FOR 18Z TAF ISSUANCE
ISSUED AT 1035 AM CST THU MAR 7 2013
CLOUDS HANGING TOUGH ACRS THE N. RAP RH PROGS SUGGEST THEY WL BE
TOUGH TO DISLODGE...AND COULD OVERSPREAD MUCH OF THE REST OF THE
AREA. BUT NOT READY TO GO ALONG WITH THAT AS MID-MARCH SUN SHOULD
HELP MIXING NR THE EDGES OF THE CLD BAND. WL STAY THE COURSE AND
HAVE A GRADUAL DECR IN CLDS ACRS THE N THIS AFTN. SOME MIDDLE AND
HIGH CLDS STREAMING ACRS RM THE W SHOULD PREVENT WIDESPREAD DENSE
FG OVERNIGHT. WL STICK WITH SOME OCNL MVFR CONDITIONS AS IN PREV
TAFS.
&&
.GRB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS.......SKOWRONSKI
SHORT TERM.....SKOWRONSKI
LONG TERM......KALLAS
AVIATION.......SKOWRONSKI
AREA FORECAST DISCUSSION
NWS GREEN BAY WI
1038 AM CST THU MAR 7 2013
UPDATED AVIATION PORTION FOR 18Z TAF ISSUANCE
.SHORT TERM...TODAY THROUGH FRIDAY.
CLOUDS AND TEMPERATURES CONTINUE TO BE THE ISSUE THIS PERIOD.
UPPER RIDGE TO BUILD IN OVER THE STATE THROUGH FRIDAY WITH SURFACE
RIDGE AXIS OVER CWA TONIGHT. STRUGGLING WITH TEMPERATURES EARLY
THIS MORNING...AS LOW CLOUDS SLOW TO EXIT THE FOX VALLEY AND
PARTS OF THE LAKESHORE. LAKE CLOUDS ALSO MOVING SOUTH INTO
NORTHERN WI. OVERNIGHT TEMPERATURES SHOWING SIG VARIABILITY...BOUNCING
AROUND AS CLOUDS MOVE IN AND OUT. TRENDS OFF SATELLITE...
SUBSIDENCE/LOWERING INVERSION HEIGHTS AND DIMINISHING LLVL WINDS
WOULD SUGGEST THE LOW CLOUDS WILL DIMINISH FAIRLY QUICKLY THIS
MORNING...LEAVING ONLY PASSING MID/HIGH CLOUDS. COLD START THIS
MORNING WOULD SUGGEST GOING BIT COOLER ON TODAYS HIGHS THAN
PREVIOUS FORECAST. GUIDANCE ALSO POINTING COLDER...THOUGH WITH
MARCH SUN AND PERSONAL BIAS TOWARDS BEING COLD ON THESE SHIFTS
WILL NOT MAKE ANY SIG CHANGE.
SURFACE RIDGE AXIS OVER STATE TONIGHT WITH LIGHT WINDS. ADDED
PATCHY FOG TO FORECAST BASED ON UPSTREAM TRENDS. TEMP FALL TO BE
LIMITED SOME BY MID/HIGH CLOUDS. WARMER ON FRI WITH SOUTHWEST
FLOW ALOFT. 850 MB TEMPS FLOATING WITH ZERO BY END OF DAY.
.LONG TERM...FRIDAY NIGHT THROUGH NEXT WEDNESDAY.
THE MAIN FOCUS OF THIS PORTION OF THE FORECAST IS THE PRECIPITATION
IMPACTS FROM A COLD FRONT PASSING ACROSS THE STATE SATURDAY INTO
SUNDAY. MEDIUM RANGE MODELS TONIGHT HAVE TIMING DIFFERENCES WITH
THE SW CONUS UPPER LOW AS IT TRACKS ACROSS THE CENTRAL PLAINS THIS
WEEKEND TOWARDS THE GREAT LAKES. THE GFS AND GEM ARE NOTABLY ON THE
FASTER SIDE OF THE SOLUTION ENVELOP STARTING BY 00Z SUNDAY COMPARED
TO THE ECMWF AND NAM. THE LATTER MODELS HAVE MORE SUPPORT FROM THE
GFS ENSEMBLE MEAN AND WILL STICK WITH THOSE MODELS...AS THEY ALSO
HAVE SUPPORT FROM HPC.
FRIDAY NIGHT THROUGH SATURDAY NIGHT...STRONG WARM ADVECTION WILL BE
OCCURRING ACROSS THE GREAT PLAINS AND SOUTH-CENTRAL CANADA FRIDAY
NIGHT AHEAD OF STRONG SHORTWAVES CONVERGING WITHIN THE NORTHERN AND
SOUTHERN BRANCH OF THE JET STREAM. PRECIPITATION WILL BE SPREADING
NORTHEAST ACROSS THE PLAINS...ON THE NOSE OF A 45-50 KT LLJ....AND
SHOULD BE APPROACHING THE NORTHERN MISSISSIPPI VALLEY BY LATE FRIDAY
NIGHT. BOTH THE NAM AND ECMWF SHOW DRY SE FLOW IN THE LOW LEVELS
OCCURRING FRIDAY NIGHT...WHICH WILL HAVE TO BE OVERCOME FOR PRECIP
TO REACH THE GROUND. THE PREVIOUS SHIFT INCREASED POPS TO MATCH
OFFICES TO OUR WEST...BUT EVIDENCE IS NOT THERE TO INCREASE POPS
FURTHER. THIS CHANGES INTO SATURDAY AS THE WARM ADVECTION SPREADS
ACROSS THE WESTERN GREAT LAKES. THE NOSE OF THE 850MB THETAE AXIS
POINTS TOWARDS CENTRAL MINNESOTA AND WESTERN WISCONSIN AND THIS IS
WHERE THE HEAVIEST PRECIP SHOULD RESIDE. BUT ENOUGH MOISTURE SHIFTS
INTO THE AREA THAT LIGHT PRECIP SHOULD ARRIVE INTO NORTH-CENTRAL
WISCONSIN SATURDAY MORNING. PTYPE UPON ARRIVAL OF THE PRECIP
REMAINS MESSY. THE SREF PORTRAYS A FAIRLY HIGH THREAT OF FREEZING
RAIN OVER CENTRAL AND NORTH-CENTRAL WISCONSIN SATURDAY MORNING. BUT
PROGGED SOUNDINGS INDICATE MAINLY A SNOW/SLEET THREAT AS PRECIP
DYNAMICALLY COOLS THE COLUMN. ENOUGH WARM ADVECTION SHOULD OCCUR BY
AFTERNOON THAT A MIXED PRECIP THREAT IS DIMINISHED AS SURFACE TEMPS
RISE ABOVE FREEZING EVEN OVER NORTH-CENTRAL WISCONSIN. WILL BACK
OFF PRECIP AMOUNTS ON SATURDAY...BUT NORTH-CENTRAL WISCONSIN COULD
STILL SEE AN INCH OR TWO OF SNOW BY SATURDAY EVENING.
MOST OF THE PRECIP SHOULD BE FALLING SATURDAY NIGHT AS THE COLD
FRONT WORKS ACROSS THE STATE. INCREASING UPPER DIVERGENCE AND
MID-LEVEL FGEN WILL SUPPORT A WIDESPREAD BAND OF PRECIP THAT SHOULD
MOSTLY FALL AS RAIN EXCEPT OVER N-C WISCONSIN WHERE A RAIN/SNOW MIX
WILL CHANGE OVER TO SNOW. WILL SLOW DOWN THE TRANSITION TO SNOW AS
THE COLDER AIR LOOKS TO BE SLOWER ARRIVING BEHIND THE FRONT. THERE
HAS BEEN SOME CONCERN ABOUT PRECIP AMOUNTS LEADING TO FLOODING.
INITIAL GUESS POINTS TOWARDS A QUARTER TO A HALF INCH OF PRECIP WILL
FALL. HEAVIER AMOUNTS MAY SPLIT THE REGION TO THE NORTH AND
SOUTH...DIRECTLY AHEAD OF THE SHORTWAVES. UNLESS THERE IS MORE
EVIDENCE THAT THE NOSE OF A LLJ WORKS INTO THE AREA...THINK FLOODING
POTENTIAL IS MINOR. BELIEVE E-C WISCONSIN STANDS THE BEST CHANCE
THOUGH...IF WERE FORCED TO PICK AN AREA THAT COULD SEE SOME
FLOODING. WILL CONTINUE TO HIGHLIGHT THREAT IN THE HWO UNTIL
EVIDENCE BECOMES MORE CLEAR.
REST OF THE FORECAST...THE FRONT WILL FINISH CROSSING THE EASTERN
PART OF THE FORECAST AREA ON SUNDAY AND LIGHT PRECIP WILL BE ONGOING
SUNDAY MORNING. PTYPE WILL BE GRADUALLY CHANGING FROM RAIN TO SNOW
OVER CENTRAL AND NORTHEAST WISCONSIN OVER THE COURSE OF THE DAY.
ANY SNOW AMOUNTS WILL LIKELY BE UP TO AN INCH. PRECIP PUSHES TO THE
SOUTHEAST SUNDAY NIGHT. HIGH PRESSURE WILL BUILD INTO THE AREA ON
MONDAY...WHEN WE SHOULD HAVE A PERIOD OF CLEARING SKIES. BUT A
CLIPPER SYSTEM WILL QUICKLY ARRIVE MONDAY NIGHT AND PASS OVER THE
AREA ON TUESDAY...WHICH WILL RETURN SNOW CHANCES. COULD SEE AN INCH
OR TWO OUT OF THIS CLIPPER. HIGH PRESSURE RETURNS ON WEDNESDAY.
COULD SEE A BIG WARMUP AT THE END OF THE WEEK THOUGH.
&&
.AVIATION...FOR 18Z TAF ISSUANCE
ISSUED AT 1035 AM CST THU MAR 7 2013
CLOUDS HANGING TOUGH ACRS THE N. RAP RH PROGS SUGGEST THEY WL BE
TOUGH TO DISLODGE...AND COULD OVERSPREAD MUCH OF THE REST OF THE
AREA. BUT NOT READY TO GO ALONG WITH THAT AS MID-MARCH SUN SHOULD
HELP MIXING NR THE EDGES OF THE CLD BAND. WL STAY THE COURSE AND
HAVE A GRADUAL DECR IN CLDS ACRS THE N THIS AFTN. SOME MIDDLE AND
HIGH CLDS STREAMING ACRS RM THE W SHOULD PREVENT WIDESPREAD DENSE
FG OVERNIGHT. WL STICK WITH SOME OCNL MVFR CONDITIONS AS IN PREV
TAFS.
&&
.GRB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM.....TE
LONG TERM......MPC
AVIATION.......SKOWRONSKI
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
346 AM CST THU MAR 7 2013
.SHORT TERM...TODAY THROUGH SATURDAY
346 AM CST THU MAR 7 2013
MAIN FORECAST CONCERNS ARE ON THE STORM SYSTEM EXPECTED TO IMPACT
THE AREA FRIDAY NIGHT THROUGH SUNDAY.
LATEST WATER VAPOR IMAGERY SHOWED A WEAK UPPER LOW OVER NORTHERN
LAKE SUPERIOR MOVING SOUTHEAST. A BROAD UPPER TROUGH WAS MOVING INTO
THE WEST COAST AS RIDGING WAS OCCURRING OVER THE CENTRAL CONUS.
SURFACE OBSERVATIONS INDICATED HIGH PRESSURE OVER THE FORECAST
AREA...WITH THE RIDGE AXIS EXTENDING FROM WESTERN ONTARIO SOUTH
THROUGH THE MID MISSISSIPPI RIVER VALLEY.
AFTER SOME PATCHY DENSE FOG THIS MORNING...HIGH PRESSURE WILL BE IN
CONTROL ACROSS THE AREA TODAY PROVIDING QUIET WEATHER. PASSING HIGH
CLOUDS...CIRRUS...ARE EXPECTED TO MOVE OVER THE AREA TODAY AS THEY
SPILL OVER THE RIDGE AHEAD OF THE TROUGH DIVING INTO THE WESTERN
U.S. PLAN ON MOSTLY SUNNY SKIES TODAY WITH HIGHS RANGING FROM THE
LOWER TO MID 30S. THE HIGH WILL START TO SLIDE EAST TONIGHT.
MEANWHILE THE WESTERN TROUGH IS EXPECTED TO DIG SOUTH THROUGH
SOUTHERN CALIFORNIA. SURFACE LOW PRESSURE WILL DEVELOP IN THE LEE
OF THE ROCKIES PRODUCING SOUTHERLY FLOW ACROSS THE PLAINS INTO THE
UPPER MISSISSIPPI RIVER VALLEY. SLIGHTLY WARMER AIR WILL ADVECT
NORTHWARD STARTING TONIGHT AND CONTINUING INTO FRIDAY. 925 MB
TEMPERATURES START OUT AROUND -7C ACROSS MOST OF THE AREA
TODAY...WARMING TO AROUND 1C OVER SOUTHEAST MINNESOTA AND TO
AROUND -5 C OVER CENTRAL WISCONSIN OVERNIGHT. PLAN ON PARTLY
CLOUDY SKIES TONIGHT WITH LOWS RANGING FORM THE LOWER 20S WEST OF
THE MISSISSIPPI RIVER TO THE TEENS FOR LOCATIONS TO THE EAST.
A WEAK SHORTWAVE LOOKS TO MOVE ACROSS NORTH DAKOTA AND INTO WESTERN
ONTARIO ON FRIDAY...PASSING WELL TO THE NORTH OF THE FORECAST AREA.
CLOUDS WILL BE ON THE INCREASE ACROSS THE UPPER MISSISSIPPI RIVER
VALLEY ON ON FRIDAY AS THE WESTERN TROUGH MOVES THROUGH THE FOUR
CORNERS REGION AND LOW PRESSURE DEEPENS OVER EASTERN COLORADO. FLOW
ALOFT WILL TURN SOUTHWEST LATE IN THE DAY ON FRIDAY OVER THE
FORECAST AREA. MEANWHILE...A NORTHERN STREAM TROUGH IS EXPECTED TO
RACE ACROSS SOUTHERN ALBERTA/SASKATCHEWAN AND MERGE WITH THE ENERGY
LIFTING OUT OF THE SOUTHWEST. AN INVERTED SURFACE TROUGH DEVELOPS
ACROSS THE UPPER MIDWEST FRIDAY NIGHT EXTENDING FROM SOUTHWEST
NEBRASKA NORTHEAST INTO NORTHWEST WISCONSIN. GULF MOISTURE SURGES
NORTHWARD FRIDAY NIGHT INTO SATURDAY WITH DEWPOINTS CLIMBING INTO
THE UPPER 40S TO LOWER 50S OVER THE CENTRAL PLAINS. A MOISTURE RICH
AIRMASS STREAMS INTO THE FORECAST AREA FRIDAY NIGHT INTO SATURDAY
MORNING WITH PRECIPITABLE WATER VALUES CLIMBING TO 8/10 OF AN INCH
BY EARLY SATURDAY MORNING...THEN INCREASING THROUGH THE DAY TO
AROUND 9/10 OF AN INCH BY SATURDAY EVENING...WHICH IS AROUND 270
PERCENT OF NORMAL. EXPECT A MIXTURE OF FREEZING RAIN AND SLEET
FRIDAY NIGHT AS THIS AIRMASS MOVES. THE MIX SHOULD SWITCH OVER TO
ALL RAIN BY MID SATURDAY MORNING. ICE ACCUMULATIONS OF 1/10 OF AN
INCH ARE POSSIBLE FROM LATE FRIDAY NIGHT INTO EARLY SATURDAY
MORNING. IN ADDITION...PATCHY FOG LOOKS TO DEVELOP WEST OF THE
MISSISSIPPI RIVER FRIDAY NIGHT AN COULD BE LOCALLY DENSE AT TIMES.
THE RAIN WILL CONTINUE THROUGH THE DAY ON SATURDAY. TEMPERATURES ARE
EXPECTED TO WARM GRADUALLY WARM FROM LATE FRIDAY NIGHT INTO SATURDAY
MORNING. HIGHS ON SATURDAY WILL RANGE FROM THE MID TO UPPER 30S OVER
NORTH CENTRAL WISCONSIN TO THE LOWER 40S ACROSS PORTIONS OF
NORTHEAST IOWA INTO FAR SOUTHWEST WISCONSIN. RAINFALL AMOUNTS ON
SATURDAY INTO SATURDAY NIGHT WILL RANGE FROM 1/2 INCH OVER NORTH
CENTRAL WISCONSIN TO AROUND 8/10 OF AN INCH OVER PORTIONS OF
NORTHEAST IOWA INTO FAR SOUTHWEST WISCONSIN. CANNOT RULE OUT SOME 1
INCH REPORTS FOR A FEW AREAS SOUTH OF INTERSTATE 90 BY EARLY SUNDAY
MORNING. SOME MELTING SNOW AND THE EXPECTED RAINFALL COULD LEAD TO
RUNOFF INTO AREA RIVERS AND STREAMS RESULTING IN SOME RISES AND
POSSIBLY ICE JAMS...SEE HYDROLOGY SECTION BELOW. THE SURFACE TROUGH
SLIDES OVER THE FORECAST AREA SATURDAY NIGHT WITH WINDS BECOMING
LIGHT. THESE LIGHT WINDS COUPLED WITH A MOIST AIRMASS OVER THE AREA
AND MELTING SNOW WILL LEAD TO DENSE FOG CONCERNS. AREAS OF DENSE FOG
COULD DEVELOP SATURDAY EVENING AND CONTINUE THROUGH THE OVERNIGHT
HOURS.
.LONG TERM...SUNDAY THROUGH WEDNESDAY
346 AM CST THU MAR 7 2013
07.00 MEDIUM RANGE MODELS ARE IN REASONABLE AGREEMENT SUNDAY INTO
MONDAY SHOWING THE UPPER TROUGH PROGRESSING EAST THROUGH THE FORECAST
AREA ON SUNDAY AND INTO THE EASTER GREAT LAKES REGION SUNDAY NIGHT.
RAIN SHOULD GRADUALLY SWITCH OVER TO SNOW FROM THE NORTHWEST TO
SOUTHEAST ON SUNDAY AS THE TROUGH MOVES IN. THE PRECIPITATION WILL
END BY SUNDAY EVENING AS HIGH PRESSURE BUILDS IN FROM THE NORTHERN
PLAINS. TEMPERATURES WILL RETURN TO MORE SEASONABLE VALUES ON MONDAY
WITH HIGHS IN THE UPPER 20S TO LOWER 30S. A FAST MOVING SHORTWAVE IS
EXPECTED TO MOVE ACROSS NORTHERN MINNESOTA INTO NORTHERN WISCONSIN
MONDAY NIGHT THROUGH TUESDAY BRINGING SNOW CHANCES TO FAR NORTH
CENTRAL WISCONSIN. HIGH PRESSURE RETURNS BY MIDWEEK WITH QUIET
WEATHER EXPECTED. HIGH TEMPERATURES TUESDAY THROUGH THURSDAY WILL
RANGE FROM THE MID TO UPPER 30S.
&&
.AVIATION...THROUGH 06Z FRIDAY
1120 PM CST WED MAR 6 2013
AS THE HIGH PRESSURE RIDGE CONTINUES TO BUILD INTO THE AREA THIS
EVENING...THE CLOUDS OVER MINNESOTA HAVE CONTINUED TO RETREAT TO
THE WEST. THESE ARE NOW MAINLY WEST OF A KMKT TO KAXA LINE AND THE
07.03Z RAP SUGGESTS THESE CLOUDS WILL NOW REMAIN WEST OF THE AREA.
SOME PATCHY DENSE FOG HAS FORMED BUT IS VARIABLE ON HOW MUCH OF
VISIBILITY RESTRICTION OCCURS. BOTH KTOB AND KAUM WERE DOWN TO
1/4SM AT 07.04Z BUT KAUM IMPROVED TO 1SM AT 07.05Z. KRST BOUNCED
FROM 6SM DOWN TO 1SM BACK UP TO 4SM BETWEEN 07.04Z AND 07.05Z.
WITH THE LIGHT WINDS AND CLEAR SKIES OVERHEAD...WOULD EXPECT THE
FOG TO CONTINUE FORMING AND HAVE TAKEN KRST DOWN TO IFR CONDITIONS
FOR THE OVERNIGHT HOURS. THE RAP IS NOT AS AGGRESSIVE WITH THE FOG
AT KLSE WITH THE BUFKIT SOUNDING SUGGESTING SATURATION AT THE
SURFACE WILL NOT OCCUR. CONFIDENCE IS NOT HIGH ON WHAT THE
VISIBILITY WILL DO AT KLSE BUT FOR NOW HAVE STAYED WITH MVFR
CONDITIONS. EXPECTING THE FOG TO DISSIPATE BY MID MORNING THURSDAY
AS THE MIXING INCREASES ON THE BACK SIDE OF THE SURFACE HIGH WITH
SOUTHEAST WINDS. ONCE THE FOG IS GONE...VFR CONDITIONS EXPECTED
FOR THE REMAINDER OF THE PERIOD.
&&
.HYDROLOGY...
346 AM CST THU MAR 7 2013
THE EXPECTED RAINFALL AND SNOWMELT FROM FRIDAY NIGHT THROUGH
SATURDAY COULD RESULT IN RUNOFF INTO AREA RIVERS AND
STREAMS...LEADING TO RISES AND POTENTIAL ICE JAMS. THE CURRENT
SNOWPACK IN PLACE ACROSS THE AREA WILL ABSORB SOME OF THE
RAINFALL. HOWEVER...THE BOTTOM LAYER OF THE SNOW PACK IS FAIRLY
HARD/CRUSTED. MOST OF THE ABSORPTION SHOULD OCCUR IN THE TOP MOST
RECENTLY FALLEN SNOW LAYER. THE TOP LAYER OF SOIL IS FROZEN SOLID
WITH CONCRETE FROST SO WHAT THE SNOW DOES NOT ABSORB WILL GO
DIRECTLY INTO RUNOFF. AT THIS TIME RAINFALL AMOUNTS OF 1/2 INCH TO
AROUND 1 INCH ARE POSSIBLE. THE HIGHER AMOUNTS WOULD MOST LIKELY
FALL ACROSS FAR NORTHEAST IOWA INTO SOUTHWEST WISCONSIN. WILL
MAINTAIN A VERY CLOSE WATCH ON THIS SITUATION.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
335 AM CST THU MAR 7 2013
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...WETENKAMP
LONG TERM...WETENKAMP
AVIATION...04
HYDROLOGY...DAS
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
1120 PM CST WED MAR 6 2013
.SHORT TERM...TONIGHT THROUGH SATURDAY
248 PM CST WED MAR 6 2013
FORECAST CONCERNS THROUGH THE SHORT TERM PERIOD INCLUDE FOG
POTENTIAL TONIGHT AND THEN LIKELIHOOD OF PRECIPITATION FRIDAY NIGHT
THROUGH SATURDAY.
HAVE BEEN WATCHING SATELLITE CLOSELY TODAY REGARDING CLEARING TREND
OF STRATOCUMULUS OR LACK THEREOF IN SOME CASES AS A RIDGE OF HIGH
PRESSURE BUILDS EAST ACROSS MN/IA. FAIRLY LARGE HOLE IN THE CLOUDS
NOW EXTENDING SOUTH WARD FROM WESTERN LAKE SUPERIOR THROUGH
SOUTHEAST MN/WESTERN WI. THIS WAS DO TO SOME MIXING ALBEIT VERY
LIGHT UNDER SUBSIDENT REGIME. FARTHER WEST UNDER THE RIDGE AXIS
ITSELF ACROSS SOUTHWEST MN/CENTRAL IA...STRATOCUMULUS WAS THICKER
WITH LACK OF MIXING. THIS COULD LEND TO A TRICKY
CLOUD/FOG/TEMPERATURES FORECAST TONIGHT.
MODEL-WISE...LOOKS LIKE REALLY NO MAJOR DIFFERENCES WERE NOTED WITH
THE 12Z RUN.
FOR TONIGHT...AS MENTIONED ABOVE...COULD BE A TRICKY FORECAST
DEPENDING ON WHAT CLOUDS DO. WHERE THE CLOUDS STICK AROUND OUT
WEST...TEMPERATURES SHOULD TREND WARMER. HOWEVER...WHERE CLEARING
OCCURS ALONG AND EAST OF THE MISSISSIPPI RIVER...TEMPERATURES COULD
REALLY TANK. THINKING FAVORED LOW-LYING BOG COUNTRY AND RELATIVELY
FRESH SNOW PACK WILL LIKELY DRIVE LOWS TONIGHT INTO THE SINGLE
DIGITS BELOW ZERO. MEANWHILE...WHERE CLOUDS LINGER...WILL LIKELY SEE
LOWS IN THE TEENS. WILL ALSO HAVE TO WATCH FOG POTENTIAL TONIGHT
GIVEN LOWER BOUNDARY LAYER MOISTURE LOADING FROM TODAY/S PARTIAL
SNOWMELT WITH DEW POINTS IN THE UPPER TEENS AS OF 2 PM. HAVE
MAINTAINED AREAS OF FOG FOR TONIGHT/EARLY THURSDAY MORNING...BUT NOT
CONFIDENT HOW THICK IT WILL BECOME DUE TO THE CLOUD ISSUE UNDER THE
RIDGE AXIS.
PLAN ON WARMING FOR THURSDAY INTO FRIDAY AS SURFACE HIGH PRESSURE
EXITS EAST OF THE AREA AND FLOW TURNS MORE SOUTHERLY. NAM HAS
925-850MB TEMPERATURES IN THE -5C TO 0C RANGE ON THURSDAY...AND -1C
TO +3C ON FRIDAY. THIS SHOULD EQUATE TO HIGHS IN THE UPPER 20S TO
LOWER 30S THURSDAY AND NEAR NORMAL LEVELS IN THE MIDDLE 30S TO
AROUND 40 ON FRIDAY.
FOR FRIDAY NIGHT INTO SATURDAY...A STRONG MID-LEVEL TROUGH COMBINED
WITH CYCLOGENESIS ON THE LEESIDE OF THE COLORADO ROCKIES/HIGH PLAINS
WILL TAP GULF MOISTURE NORTHWARD TOWARD THE AREA. NAM/GFS SHOWING
NOSE OF INCREASING 925-850MB MOISTURE TRANSPORT GETTING INTO THE
AREA BY FRIDAY EVENING WITH PRECIPITABLE WATER VALUES REACHING AROUND
0.75 INCH OR 200-250 PERCENT ABOVE NORMAL BY SATURDAY 12Z. NAM
SOUNDINGS SHOW INITIALLY DRY LOWER LEVELS WITH COLUMN SATURATION
OCCURRING AT OR ABOVE 700MB BEFORE MIDNIGHT...THEN TOTAL COLUMN
SATURATION BY 12Z SATURDAY MORNING. AS SUCH...HELD PRECIPITATION TO
CHANCE CATEGORY BEFORE MIDNIGHT FRIDAY...AND THEN LIKELY CATEGORY
//WEST OF THE MISSISSIPPI RIVER//AFTER MIDNIGHT. NOW...AS FAR AS
P-TYPE...THERMAL PROFILES SUPPORT A WINTRY MIX THROUGH FRIDAY NIGHT
WITH FREEZING RAIN AND SLEET THE LIKELY OUTCOME.
THROUGH THE DAY SATURDAY...WILL LIKELY SEE A TRANSITION FROM A
WINTRY MIX TO ALL RAIN AS WARMING CONTINUES AHEAD OF THE MID-LEVEL
TROUGH AND SURFACE LOW MOVING OUT OF THE PLAINS. GULF MOISTURE TAP
CONTINUES INTO THE AREA WITH PRECIPITABLE WATER VALUES INCREASING
INTO THE 0.75-1.00 INCH RANGE. MELTING SNOW AND RAINFALL INCREASES
HYDROLOGY CONCERNS. HAVE INCLUDED A SEPARATE DISCUSSION SECTION
BELOW TO SORT OUT THE DETAILS.
MAY HAVE TO CONSIDER EVENTUAL HEADLINES FRIDAY NIGHT INTO SATURDAY
MORNING FOR WINTRY MIX SCENARIO.
.LONG TERM...SATURDAY NIGHT THROUGH WEDNESDAY
248 PM CST WED MAR 6 2013
06.12Z MEDIUM RANGE MODELS IN GOOD AGREEMENT. EXPECT A TRANSITION
FROM RAIN TO SNOW AND PERHAPS SOME SLEET SATURDAY NIGHT AS A COLD
FRONT DROPS THROUGH THE UPPER MISSISSIPPI RIVER VALLEY REGION. THEN
FOR SUNDAY THROUGH MONDAY...A WAVE OF LOW PRESSURE RIPPLES
NORTHEAST ALONG THIS FRONTAL BOUNDARY WITH DEFORMATION RAIN/SNOW
EXTENDING NORTHWESTWARD INTO THE FORECAST AREA. WEATHER LOOKS
FAIRLY QUIET MONDAY NIGHT THROUGH WEDNESDAY WITH WEST/NORTHWEST
FLOW ACROSS THE AREA. WILL KEEP A EYE ON A WEAK MID-LEVEL TROUGH
DROPPING INTO THE AREA MONDAY NIGHT/TUESDAY TIME FRAME FOR A
CHANCE OF LIGHT SNOW MAINLY NORTH OF I-94. OTHERWISE...WITH
WEST/NORTHWEST FLOW ALOFT...LOOK FOR NORMAL TO SLIGHTLY BELOW
NORMAL TEMPERATURES THROUGH THE PERIOD WITH HIGHS MAINLY IN THE
MIDDLE/UPPER 30S.
&&
.AVIATION...THROUGH 06Z FRIDAY
1120 PM CST WED MAR 6 2013
AS THE HIGH PRESSURE RIDGE CONTINUES TO BUILD INTO THE AREA THIS
EVENING...THE CLOUDS OVER MINNESOTA HAVE CONTINUED TO RETREAT TO
THE WEST. THESE ARE NOW MAINLY WEST OF A KMKT TO KAXA LINE AND THE
07.03Z RAP SUGGESTS THESE CLOUDS WILL NOW REMAIN WEST OF THE AREA.
SOME PATCHY DENSE FOG HAS FORMED BUT IS VARIABLE ON HOW MUCH OF
VISIBILITY RESTRICTION OCCURS. BOTH KTOB AND KAUM WERE DOWN TO
1/4SM AT 07.04Z BUT KAUM IMPROVED TO 1SM AT 07.05Z. KRST BOUNCED
FROM 6SM DOWN TO 1SM BACK UP TO 4SM BETWEEN 07.04Z AND 07.05Z.
WITH THE LIGHT WINDS AND CLEAR SKIES OVERHEAD...WOULD EXPECT THE
FOG TO CONTINUE FORMING AND HAVE TAKEN KRST DOWN TO IFR CONDITIONS
FOR THE OVERNIGHT HOURS. THE RAP IS NOT AS AGGRESSIVE WITH THE FOG
AT KLSE WITH THE BUFKIT SOUNDING SUGGESTING SATURATION AT THE
SURFACE WILL NOT OCCUR. CONFIDENCE IS NOT HIGH ON WHAT THE
VISIBILITY WILL DO AT KLSE BUT FOR NOW HAVE STAYED WITH MVFR
CONDITIONS. EXPECTING THE FOG TO DISSIPATE BY MID MORNING THURSDAY
AS THE MIXING INCREASES ON THE BACK SIDE OF THE SURFACE HIGH WITH
SOUTHEAST WINDS. ONCE THE FOG IS GONE...VFR CONDITIONS EXPECTED
FOR THE REMAINDER OF THE PERIOD.
&&
.HYDROLOGY...
248 PM CST WED MAR 6 2013
CONCERN INCREASING SLIGHTLY WITH ANTICIPATED RAINFALL/SNOWMELT
FRIDAY NIGHT THROUGH SATURDAY NIGHT. MODELS INDICATING A GOOD SLUG
OF GULF MOISTURE ADVECTING NORTHWARD INTO THE UPPER MISSISSIPPI
RIVER REGION. RIGHT NOW...EXPECTING RAINFALL//CENTERED ON SATURDAY//
OF A 1/4 TO 1/2 INCH. THINKING THAT CURRENT SNOWPACK IN PLACE WOULD
BE ABLE TO ABSORB MOST OF THIS RAINFALL AS SNOWPACK TEMPERATURES
STILL IN THE TEENS ACROSS NORTH CENTRAL WISCONSIN...AND IN THE
MIDDLE 20S ACROSS SOUTHERN WI/NORTHEAST IA. HOWEVER...IF WE DO END
UP WITH MORE RAINFALL GIVEN FAIRLY HIGH PRECIPITABLE WATER VALUES IN
THE COLUMN OF ATMOSPHERE...OR WARMER TEMPERATURES AND FURTHER
RIPENING OF THE SNOWPACK...RUNOFF COULD BECOME A PROBLEM. FROST
DEPTH IS QUITE DEEP /1.5 TO 3 FEET/ AND THE TOP SEVERAL INCHES ARE
FROZEN SOLID WITH CONCRETE FROST. ANY SNOWMELT OR RAINFALL WILL ALL
RUN OFF INTO WATERWAYS. THERE IS ALSO ICE IN SOME OF OUR CREEKS AND
RIVERS...SO IF THERE IS A RISE...WE COULD ALSO SEE SOME ICE ACTION.
AS SUCH...WE WILL CONTINUE TO KEEP A CLOSE EYE ON THIS
SITUATION.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
248 PM CST WED MAR 6 2013
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...DAS
LONG TERM...DAS
AVIATION...04
HYDROLOGY...DAS
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
321 AM CST SAT MAR 9 2013
.DISCUSSION...
924 PM CST
NO REAL BIG CHANGES TO GOING FORECAST TONIGHT...WITH ONLY MINOR
EDITS TO POP/WX FOR AREAS ACROSS NORTHWEST ILLINOIS.
LATEST SATELLITE IMAGERY DEPICTING MID/UPPER LEVEL CLOUD COVER
CONTINUING TO STREAM NORTHEAST ACROSS THE REGION THIS EVENING...AS
SOUTHWESTERLY FLOW CONTINUES OUT AHEAD OF AN APPROACHING LONGWAVE
TROUGH OVER THE WESTERN CONUS. THIS IS USHERING IN A WARMER AND
MORE MOIST ENVIRONMENT WITH LATEST RAP ANALYSIS DEPICTING STRONG
WAA OCCURRING ACROSS MUCH OF THE PLAINS...AND CAN BE NOTED VIA THE
ABUNDANCE OF CLOUD COVER AS WELL AS THE WIDESPREAD PRECIP SHIELD
IN THIS LOCATION. ALTHOUGH THE STRONGEST WAA WILL REMAIN JUST TO
THE WEST OF THE CWA...LATEST SHORT TERM GUIDANCE IS INDICATING
THAT SOME LIGHT PRECIP DEVELOPMENT COULD OCCUR ACROSS NORTHWEST
ILLINOIS TONIGHT AS THIS WAA WING CONTINUES TO LIFT
NORTH/NORTHEAST. PRECIP DEVELOPMENT LATE TONIGHT ACROSS AREAS
ALONG AND WEST OF INTERSTATE 39 DOES SEEM REASONABLE WITH THIS
BETTER FORCING ALREADY INCHING CLOSER TO THE CWA. ALTHOUGH THIS
FORCING WILL REMAIN RATHER WEAK...IT MAY BE ENOUGH OF A PERSISTENT
FEATURE TO OVERCOME SOME DRIER AIR IN PLACE. THERMAL PROFILES WILL
SUPPORT PRECIP OF THE LIQUID TYPE...BUT WITH THE POSSIBILITY OF A
BRIEF WINDOW OF LIGHT FREEZING RAIN. ALTHOUGH...WARMING TONIGHT
SHOULD MITIGATE ANY OVERALL FREEZING RAIN POTENTIAL WITH SURFACE
TEMPERATURES EXPECTED TO BE HOVERING AROUND FREEZING IF NOT
BEGINNING TO RISE JUST ABOVE BY THE TIME THIS PRECIP ARRIVES. SO
HAVE MADE MENTION OF A SLIGHT CHANCE OF LIGHT RAIN/LIGHT FREEZING
RAIN FOR LATE TONIGHT INTO EARLY SATURDAY MORNING BEFORE
TEMPERATURES CONTINUE TO RISE THROUGH MID SATURDAY MORNING WITH
ONLY RAIN THEN EXPECTED.
RODRIGUEZ
//PREV DISCUSSION...
234 PM CST
THE AREA WILL QUICKLY SHIFT FROM WINTER TO SPRING WEATHER THIS
WEEKEND WITH EXPECTED RAINFALL/SNOW MELT WITH WARMING TEMPERATURES
POSING A FLOOD THREAT...WITH THUNDERSTORMS NOT OUT OF THE QUESTION
BY SUNDAY. UPS AND DOWNS IN TEMPERATURES ARE EXPECTED NEXT WEEK WITH
A SERIES OF WEAKER SYSTEMS BRINGING PERIODIC LOW CHANCES FOR
PRECIPITATION.
SYNOPSIS...EARLY AFTERNOON WATER VAPOR IMAGERY SHOWS UPPER RIDGING
BUILDING ACROSS THE MISSISSIPPI RIVER VALLEY INTO THE LOCAL AREA IN
RESPONSE TO A DEEP CLOSED UPPER LOW ROTATING INTO THE DESERT
SOUTHWEST. THIS TROUGH IS SPLIT FROM A TROUGH THAT IS POSITIONED
OVER CENTRAL CANADA WITH A TROUGH AXIS SHIFTING TOWARDS WESTERN
SASKATCHEWAN. THESE TWO FEATURES WILL BE THE MAIN DRIVERS OF
EXPECTED RAINFALL THIS WEEKEND. AT THE SURFACE...A LARGE AREA OF
HIGH PRESSURE IS EXITING THE LOCAL AREA TO THE EAST. WEAK LOW
PRESSURE IS OVER SOUTHERN MANITOBA AND IS DRIFTING EASTWARD.
TONIGHT AND SATURDAY...QUIET WEATHER WILL CONTINUE TONIGHT WITH THE
UPPER RIDGE CRESTING THE AREA THIS EVENING. THE BIG SOUTHWEST
TROUGH WILL BE MOVING EASTWARD WITH HEIGHT FALLS AHEAD OF IT AND
BEHIND THE RIDGE ALLOWING LOW PRESSURE TO DEVELOP IN THE LEE OF
THE ROCKIES. A 50+KT LOW LEVEL JET WILL SET UP ACROSS THE PLAINS
RESULTING IN A STRONG PUSH OF HIGH THETA-E LOW LEVEL AIR ACROSS
THE SOUTHERN AND CENTRAL PLAINS. HIGH LEVEL MOISTURE WILL BE
SPREAD NORTHEASTWARD SUPPORTING AN INCREASE IN MID AND HIGH LEVEL
CLOUD COVER OVERNIGHT. THE PRESSURE GRADIENT WILL BE WEAK ACROSS
THE AREA EARLY BUT WILL TIGHTEN OVERNIGHT SO WINDS MAY DROP OFF
FOR A TIME EARLY BEFORE INCREASING SOMEWHAT OVERNIGHT. LOW TEMPS
WILL BE THE MAIN CHALLENGE AND MAY OCCUR DURING THE EVENING BUT
SOME WARMING MAY OCCUR LATE AS CLOUDS AND WINDS INCREASE AND WARM
ADVECTION IS UNDERWAY ALOFT. WILL GO AHEAD AND SHOW A STEADY OR
WARMING TREND OVERNIGHT. LIGHT PRECIP BECOMES A CONCERN BY
SATURDAY MORNING AS WAVES OF WARM ADVECTION BECOME MORE FOCUSED
AND MOISTURE DEEPENS. THIS IS WHERE TEMPS WILL BECOME CRITICAL
BECAUSE CHANCES FOR LIGHT PRECIP MAY BEGIN EARLY ENOUGH TO FALL AS
FREEZING RAIN. SIGNALS FOR PRECIP ARE NOT ALL THAT ORGANIZED UNTIL
SATURDAY AFTERNOON BUT WESTERN AREAS MAY HAVE DEEP ENOUGH MOISTURE
AND ENOUGH WARM ASCENT OCCURRING ALOFT TO SEE LIGHT RAIN...OR
FREEZING RAIN IF TEMPS START OUT BELOW FREEZING...BY LATE SATURDAY
MORNING. ANY FREEZING PRECIP WILL QUICKLY END AS TEMPS WARM WELL
ABOVE FREEZING BY EARLY AFTERNOON. PRECIP CHANCES WILL THEN EXPAND
EASTWARD...ESPECIALLY ACROSS THE NORTHERN CWA SATURDAY AFTERNOON
BUT CHANCES STILL LOOK RATHER LOW BUT STILL WORTH A MENTION GIVEN
STEADILY INCREASING DEEP LAYER MOISTURE /PRECIPITABLE WATER VALUES
REACH 0.75 INCHES OR SO BY LATE DAY/ AND WARM ADVECTION. SOUTH TO
SOUTHEAST WINDS WILL BECOME BREEZY WHICH WILL HELP HIGHS WARM INTO
LOW TO MID 40S NORTH AND MID TO UPPER 40S SOUTH. IT IS ALSO
IMPORTANT TO NOTE THAT DEW POINTS WILL BE ON THE RISE AS WELL
WHICH WILL COMBINE WITH THE STEADY WINDS AND MILD TEMPS TO PROVIDE
INCREASINGLY EFFICIENT SNOW MELT THROUGH THE AFTERNOON. MORE ON
THIS BELOW...
SATURDAY NIGHT AND SUNDAY...THE SOUTHWEST UPPER LOW WILL BE
LIFTING ACROSS THE SOUTHERN HIGH PLAINS AND PHASING WITH THE CENTRAL
CANADA UPPER TROUGH WHICH WILL BE SHARPENING AS IT PIVOTS
SOUTHEASTWARD. THE MAIN SURFACE LOW IS EXPECTED TO ORGANIZE IN
VICINITY OF THE SOUTHERN UPPER LOW ACROSS WESTERN KANSAS BY SATURDAY
EVENING WITH AN INVERTED TROUGH EXTENDING NORTHWARD INTO WESTERN
ONTARIO. GULF MOISTURE WILL CONTINUE TO STREAM NORTHWARD AHEAD OF
THE LOW AS 60KT LOW LEVEL JET SPREADS ACROSS
MISSOURI...ILLINOIS...AND LAKE MICHIGAN LATER SATURDAY EVENING.
PRECIPITABLE WATER VALUES WILL FURTHER SURGE REACHING THE 1 TO
PERHAPS 1.25 INCH RANGE WHICH WILL COMBINE WITH INCREASED ASCENT TO
PRODUCE WIDESPREAD RAIN ACROSS THE MID-MISSISSIPPI RIVER VALLEY
WHICH WILL THEN SPREAD EASTWARD DURING THE EVENING AND OVERNIGHT
HOURS. THE UPPER LOW WILL BE TO THE WEST OF THE AREA BY SUNDAY
MORNING WHICH WILL LIKELY BRING A DRY SLOT INTO THE AREA SOMETIME
SUNDAY MORNING. INSTABILITY DOES INCREASE AS WELL...POTENTIALLY WITH
ENOUGH ELEVATED INSTABILITY TO SUPPORT SOME THUNDER POTENTIAL ON THE
LEADING EDGE OF THE DRY SLOT. FURTHERMORE...SOME MINIMAL SURFACE
INSTABILITY COULD DEVELOP AS WELL WHICH WOULD POSE AN ADDITIONAL
THUNDER THREAT...ESPECIALLY ALONG THE APPROACHING COLD FRONT WHICH
WILL CROSS THE AREA LATER IN THE DAY. HOWEVER...THE DEEPER DRY AIR
OF THE DRY SLOT MAY PRECLUDE MUCH IF ANY DEVELOPMENT ALONG THE FRONT
IF SURFACE BASED INSTABILITY DOES IN FACT DEVELOP. STILL TOO EARLY
TO HAVE ANY HIGH DEGREE OF CONFIDENCE IN THUNDER POTENTIAL BUT FEEL
THIS BEARS WATCHING GIVEN THE HIGH DEGREE OF DEEP LAYER WIND SHEAR
AND FAIRLY STRONG LOW LEVEL WIND FIELD. HIGH TEMPS SUNDAY LOOK TO
RANGE FROM THE MID 40S NORTHWEST TO THE MID 50S SOUTHEAST.
PRECIP AMOUNTS/FLOODING POTENTIAL...FORECAST GUIDANCE IS IN PRETTY
GOOD AGREEMENT WITH THE TRACK OF LOW LEVEL FEATURES BUT DO DIFFER
IN THE PLACEMENT OF OTHER FEATURES SUCH AS THE PATH OF THE UPPER
JET CORE. QPF OUTPUT DOES DIFFER SOMEWHAT AS A RESULT...ESPECIALLY
IN PLACEMENT OF HEAVIEST VALUES. ARRIVAL TIMING MAY ALSO NEED
ADJUSTMENT WITH SOME GUIDANCE BEING SLOWER BUT RIGHT NOW THE
DIFFERENCES ARE ON THE ORDER OF A FEW HOURS. THE WESTERN AND
NORTHERN CWA CONTINUES TO LOOK TO HAVE THE BEST CHANCE AT
RECEIVING PEAK RAINFALL AMOUNTS...OR ROUGHLY FROM CHICAGO TO
PONTIAC AND POINTS WEST BUT THE ENTIRE CWA DOES LOOK TO SEE
RAINFALL. GIVEN THE PRECIPITABLE WATER VALUES AND DURATION OF
FORCING...AMOUNTS OF 0.75-1.00 INCHES ARE PLAUSIBLE IN THE NORTH
AND WEST WITH LESSER AMOUNTS SOUTHEAST. IF CONVECTION CAN DEVELOP
SUNDAY MORNING THEN AMOUNTS WOULD BE HIGHER IN SPOTS BUT IT IS
POSSIBLE THAT THE BEST CHANCE FOR CONVECTION COULD END UP BEING
ACROSS THE SOUTHERN/EASTERN CWA GIVEN THE LIKELY TRACK OF THE DRY
SLOT AND ARRIVAL OF INSTABILITY. SO CONFIDENCE IN SPECIFIC AMOUNTS
AND WHERE THEY OCCUR IS STILL LIMITED. HOWEVER...EVEN SOMEWHAT
LOWER AMOUNTS THAN THOSE ABOVE ARE STILL A CONCERN GIVEN THE
AMOUNT OF WATER IN THE CURRENT SNOW PACK. REFERENCE HYDROLOGY
SECTION BELOW AND ESFLOT PRODUCT FOR MORE DETAILS.
SUNDAY NIGHT AND MONDAY...TIMING DIFFERENCES BECOME MORE CRITICAL AS
THE SYSTEM DEPARTS SUNDAY NIGHT AND MONDAY. IN TERMS OF FRONTAL
TIMING...THERE IS GOOD AGREEMENT ON HAVING THE COLD FRONT SWEEP
ACROSS THE AREA SUNDAY AFTERNOON WHICH ALLOWS COLDER AIR TO
ARRIVE...BUT THE SPEED WITH WHICH IT ARRIVES IS NOT QUITE CLEAR. THE
ECMWF/GEM REMAIN SLOWER WITH THE PASSAGE OF THE UPPER TROUGH AXIS
DELAYING THE ARRIVAL OF COLDEST AIR...AS WELL AS THE ATTENDANT
DEFORMATION FORCING HOLDING IT OFF UNTIL CLOSER TO MONDAY MORNING.
THE NAM AND GFS ARE FASTER WITH THE UPPER TROUGH AND ARRIVAL OF COLD
AIR. THIS WILL PLAY HAVOC WITH PRECIP TIMING AND TYPE BEHIND THE
FRONT INTO MONDAY MORNING. WILL NEED TO MONITOR THIS PERIOD AS THERE
IS AT LEAST SOME SUPPORT FOR MEASURABLE PRECIP MONDAY.
MDB
LONG TERM...MONDAY NIGHT THROUGH FRIDAY...
THE EXTENDED PERIOD WILL FEATURE A FAIRLY PROGRESSIVE NORTHWEST TO
PERHAPS ZONAL FLOW WITH SEVERAL WEAK SYSTEMS TO AFFECT PART OF THE
REGION/GREAT LAKES. TIMING ANY OF THESE FEATURES IS SOMEWHAT
DIFFICULT AS THEIR STRENGTH/LOCATION CONTINUES TO FLUCTUATE FROM
RUN TO RUN AS WELL AS FROM MODEL TO MODEL. WHILE THERE WILL BE A
FEW CHANCES FOR PRECIP...WILL CONTINUE WITH MAINLY A DRY FORECAST
DUE TO LOW CONFIDENCE THOUGH HAVE INCLUDED A SLIGHT CHANCE OF
SHOWERS ON FRIDAY AS THERE HAS BEEN SOME CONTINUITY DURING THIS TIME
PERIOD. SHOULD PRECIP CHANCES/TRENDS INCREASE...PRECIP TYPE WILL
BECOME A CONCERN DEPENDING ON TIME OF DAY.
TEMPERATURES ARE EQUALLY CHALLENGING...DEPENDING ON THE TIMING OF
THESE FEATURES AND THE EXTENT OF COLD AIR THEY BRING WITH THEM.
ECMWF HAD BEEN FAIRLY CONSISTENT WITH A PUSH OF COLDER AIR THURSDAY
INTO FRIDAY WHICH IS NOW GONE WHILE THE GFS IS NOW MUCH COLDER. HAVE
TRENDED MIDDLE OF THE ROAD WITH TEMPS AND GIVEN MID MARCH SUNSHINE...
LACK OF ANY SIGNIFICANT COLD AIR PUSH WOULD SUPPORT TEMPS NEAR
SEASONAL NORMALS.
CMS
&&
.HYDROLOGY...
234 PM CST
SOME AREAS OF THE FORECAST AREA MAY SEE 0.75-1.00 INCHES
OF RAINFALL FROM SATURDAY THROUGH SUNDAY...WITH THE BULK EXPECTED
SATURDAY EVENING/NIGHT. AT THIS POINT...THESE RAINFALL AMOUNTS ARE
EXPECTED GENERALLY WEST OF A LINE FROM CHICAGO TO PONTIAC WITH
LESSER AMOUNTS SOUTHEAST BUT THERE IS SOME OPPORTUNITY FOR THE
LOCATION TO NEED ADJUSTMENT. IN ADDITION...SOME CONVECTIVE
RAINFALL IS POSSIBLE WHICH COULD RESULT IN LOCALLY HIGHER AMOUNTS.
OBSERVED SNOW CORE WATER EQUIVALENTS RANGE FROM AROUND AN INCH TO
AROUND 2.5 INCHES WHERE THE DEEPEST SNOW EXISTS...MAINLY NORTH OF
INTERSTATE 80. FROST DEPTH REMAINS IN THE 6 TO 10 INCH RANGE. THE
EXPECTATION IS THAT THE SNOW WILL MELT AND RUNOFF WILL BE REALIZED
BEFORE THE FROST MELTS SIGNIFICANTLY DUE TO THE INSULATING
EFFECTS OF THE SNOW PACK. SNOW MELT WILL COMMENCE BEFORE THE BULK
OF THE RAINFALL WHICH COULD ALLOW SOME OF THE RUNOFF INTO AREA
RIVERS AND STREAMS TO MAKE PROGRESS DOWNSTREAM BUT THIS WOULD
LIKELY BE MINIMAL. MOST MELT WILL LIKELY OCCUR WITH THE RAINFALL
SO RIVER RISES WILL OCCUR AND SOME RIVERS COULD EXCEED FLOOD STAGE
LATER SUNDAY/MONDAY. AREAL OVERLAND FLOODING IS A
POSSIBILITY...MAINLY IN LOW LYING AND POORLY DRAINED AREAS.
REFERENCE ESFLOT FOR ADDITIONAL INFORMATION.
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 09Z...
* CHANCE OF SOME LIGHT RAIN THIS AFTERNOON.
* RAIN AND FOG TIMING TONIGHT.
* MVFR CIGS AND VISIBILITY LIKELY AFTER 06 UTC SATURDAY NIGHT.
* IFR CIGS AND VISIBILITY POSSIBLE BY DAYBREAK ON SUNDAY MORNING.
* LLWS POSSIBLE SATURDAY NIGHT.
KJB
//DISCUSSION...UPDATED 06Z...
THE MAIN CONCERNS DURING THE PERIOD WILL BE WITH OUR NEXT STORM
SYSTEM...WHICH IS CURRENTLY TAKING SHAPE ACROSS THE FRONT RANGE OF
THE COLORADO ROCKIES. THIS SYSTEM IS ALREADY TRANSPORTING WARM AND
MOIST AIR NORTHWARD ACROSS THE PLAINS AND INTO THE MID MISSOURI
VALLEY WITH SCATTERED SHOWERS AND EVEN SOME THUNDERSTORMS ONGOING
ACROSS THIS REGION.
IT APPEARS SOME OF THESE SHOWERS MAY EFFECT KRFD AROUND
DAYBREAK...AND WITH TEMPERATURES POSSIBLY NEAR FREEZING...I OPTED TO
LEAVE THE -FZRA IN THE NEW TAF FROM 12-14 UTC THIS MORNING.
HOWEVER...I HAVE LOW CONFIDENCE IN THE FREEZING THREAT AS
TEMPERATURES MAY ACTUALLY JUMP ABOVE FREEZING PRIOR TO THE ONSET OF
THE PRECIPITATION. IN ADDITION...I AM NOT SURE HOW MUCH IF ANY PRECIP
WILL ACTUALLY FALL THIS MORNING. THERE IS STILL SOME DRY AIR IN THE
LOW LEVELS TO OVERCOME...AND IT APPEARS THAT CIGS WILL STILL BE AT
OR ABOVE 9000 FEET THROUGH 15 UTC. WITH THIS IN MIND...WE MAY NOT
SEE MORE THAN A FEW SPRINKLES DURING THE EARLY MORNING HOURS AT
KRFD.
IT APPEARS MOST OF THE DAY PRIOR TO 20 UTC WILL BE DRY. AFTER 20 UTC
WE COULD GET ANOTHER BATCH OF LIGHT RAIN ACROSS THE TAF SITES. THIS
ALSO APPEARS AS THOUGH IT WILL BE RATHER LIGHT...AND I HAVE OPTED TO
KEEP THE PROB 30 GROUP GOING FOR THIS ACTIVITY. I
DID...HOWEVER...TRIM THE END TIME OF THE PROB 30 GROUP TO 01 UTC AS
IT APPEARS THERE WILL BE QUITE A BIT OF DRY TIME THIS EVENING AHEAD
OF THE MAIN BATCH OF RAIN.
RAIN SHOULD ONSET AROUND OR SHORTLY AFTER 03 UTC THIS EVENING AT
KRFD AND AFTER 06 UTC AT THE EASTERN TERMINALS AS THE MAIN STORM
SYSTEM APPROACHES THE AREA. IT APPEARS THE RAIN WILL BE MODERATE AT
TIMES WITH CIGS GRADUALLY LOWERING INTO THE IFR CATEGORY BY EARLY
SUNDAY. VISIBILITIES WILL ALSO BE DEGRADING INTO AT LEAST THE
MVFR RANGE IN RAIN AND FOG. LOW CLOUDS AND FOG LOOK TO CONTINUE INTO
THE DAY ON SUNDAY AS THE SURFACE LOW MOVES OVERHEAD AND SURFACE
DEW POINTS PEAK IN THE LOWER TO MIDDLE 40S.
THERE IS ALSO A CHANCE OF LLWS SATURDAY NIGHT AS IT APPEARS THE A
SOUTHWESTERLY 50-55 LOW LEVEL JET WILL DEVELOP AROUND 2,000 FT AGL.
SURFACE WINDS DURING THIS TIME ARE EXPECTED TO BE AROUND 10 KT OUT
OF THE SOUTH. I HAVE OPTED NOT TO ADD THIS TO THE NEW TAF...BUT IT
MAY NEED TO BE ADDED AT A LATER TIME IF THESE CONDITIONS APPEAR TO BE
SETTING UP.
KJB
//ORD AND MDW CONFIDENCE...UPDATED 09Z...
* LOW CONFIDENCE ON ANY LIGHT RAIN AFFECTING THE TERMINALS THIS
AFTERNOON.
* MEDIUM TO HIGH CONFIDENCE IN RAIN AND FOG REDUCING VISIBILITIES
UNDER 4 MILES LATER SUNDAY NIGHT AFTER 06 UTC.
* MEDIUM CONFIDENCE IN IFR CIGS TOWARDS DAYBREAK SUNDAY.
* LOW TO MEDIUM CONFIDENCE IN LLWS SATURDAY NIGHT.
KJB
//OUTLOOK FOR ORD/MDW FOR 12Z SUNDAY-12Z FRIDAY...UPDATED 00Z...
SUNDAY...RAIN AND FOG WITH LIKELY IFR. A CHANCE FOR A MIX WITH
SNOW DURING THE NIGHT.
MONDAY...SLIGHT CHANCE OF RAIN AND SNOW WITH MVFR.
TUESDAY-THURSDAY...VFR.
MTF
&&
.MARINE...
228 AM CST
A STORM SYSTEM...CURRENTLY TAKING SHAPE ACROSS THE FRONT RANGE OF
THE COLORADO ROCKIES...WILL SPLIT OFF INTO TWO SYSTEMS. ONE WILL
RACE NORTHEASTWARD ACROSS ONTARIO BY SUNDAY...WHILE THE SECOND SYSTEM
MOVES TOWARDS THE SOUTHERN END OF LAKE MICHIGAN BY SUNDAY EVENING.
THIS SECOND SYSTEM LOOKS TO HAVE A LARGE IMPACT ON THE WINDS OVER
THE LAKE THROUGH THE WEEKEND.
SOUTHERLY WINDS WILL OCCUR TODAY AND TONIGHT...UP AROUND 25 KT
AHEAD OF THIS SYSTEM. THEN AS THE SURFACE LOW APPROACHES THE LAKE ON
SUNDAY...THE WINDS WILL BECOME NORTH-NORTHEASTERLY AND INCREASE UP
AROUND 30 KT...ESPECIALLY ACROSS THE NORTHERN END OF THE LAKE.
GALE FORCE WINDS ARE QUITE POSSIBLE WITH THIS SYSTEM...BUT
UNCERTAINTIES REMAIN AS TO THE EXACT TRACK OF THIS SYSTEM...AND
HENCE WHERE THE STRONGEST WINDS WILL BE.
ONCE THIS LOW PASSES OVER THE LAKE...A PERIOD OF NORTHWESTERLY WINDS
OF 25 TO 30 KT LOOKS LIKELY INTO AT LEAST MONDAY. HOWEVER...THESE
NORTHWESTERLY WINDS COULD CONTINUE INTO MIDWEEK AS IT APPEARS A
WEAK CLIPPER SYSTEM MAY MOVE ACROSS THE LAKE SOMETIME ON TUESDAY OR
TUESDAY EVENING.
KJB
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
229 AM CST SAT MAR 9 2013
.DISCUSSION...
924 PM CST
NO REAL BIG CHANGES TO GOING FORECAST TONIGHT...WITH ONLY MINOR
EDITS TO POP/WX FOR AREAS ACROSS NORTHWEST ILLINOIS.
LATEST SATELLITE IMAGERY DEPICTING MID/UPPER LEVEL CLOUD COVER
CONTINUING TO STREAM NORTHEAST ACROSS THE REGION THIS EVENING...AS
SOUTHWESTERLY FLOW CONTINUES OUT AHEAD OF AN APPROACHING LONGWAVE
TROUGH OVER THE WESTERN CONUS. THIS IS USHERING IN A WARMER AND
MORE MOIST ENVIRONMENT WITH LATEST RAP ANALYSIS DEPICTING STRONG
WAA OCCURRING ACROSS MUCH OF THE PLAINS...AND CAN BE NOTED VIA THE
ABUNDANCE OF CLOUD COVER AS WELL AS THE WIDESPREAD PRECIP SHIELD
IN THIS LOCATION. ALTHOUGH THE STRONGEST WAA WILL REMAIN JUST TO
THE WEST OF THE CWA...LATEST SHORT TERM GUIDANCE IS INDICATING
THAT SOME LIGHT PRECIP DEVELOPMENT COULD OCCUR ACROSS NORTHWEST
ILLINOIS TONIGHT AS THIS WAA WING CONTINUES TO LIFT
NORTH/NORTHEAST. PRECIP DEVELOPMENT LATE TONIGHT ACROSS AREAS
ALONG AND WEST OF INTERSTATE 39 DOES SEEM REASONABLE WITH THIS
BETTER FORCING ALREADY INCHING CLOSER TO THE CWA. ALTHOUGH THIS
FORCING WILL REMAIN RATHER WEAK...IT MAY BE ENOUGH OF A PERSISTENT
FEATURE TO OVERCOME SOME DRIER AIR IN PLACE. THERMAL PROFILES WILL
SUPPORT PRECIP OF THE LIQUID TYPE...BUT WITH THE POSSIBILITY OF A
BRIEF WINDOW OF LIGHT FREEZING RAIN. ALTHOUGH...WARMING TONIGHT
SHOULD MITIGATE ANY OVERALL FREEZING RAIN POTENTIAL WITH SURFACE
TEMPERATURES EXPECTED TO BE HOVERING AROUND FREEZING IF NOT
BEGINNING TO RISE JUST ABOVE BY THE TIME THIS PRECIP ARRIVES. SO
HAVE MADE MENTION OF A SLIGHT CHANCE OF LIGHT RAIN/LIGHT FREEZING
RAIN FOR LATE TONIGHT INTO EARLY SATURDAY MORNING BEFORE
TEMPERATURES CONTINUE TO RISE THROUGH MID SATURDAY MORNING WITH
ONLY RAIN THEN EXPECTED.
RODRIGUEZ
//PREV DISCUSSION...
234 PM CST
THE AREA WILL QUICKLY SHIFT FROM WINTER TO SPRING WEATHER THIS
WEEKEND WITH EXPECTED RAINFALL/SNOW MELT WITH WARMING TEMPERATURES
POSING A FLOOD THREAT...WITH THUNDERSTORMS NOT OUT OF THE QUESTION
BY SUNDAY. UPS AND DOWNS IN TEMPERATURES ARE EXPECTED NEXT WEEK WITH
A SERIES OF WEAKER SYSTEMS BRINGING PERIODIC LOW CHANCES FOR
PRECIPITATION.
SYNOPSIS...EARLY AFTERNOON WATER VAPOR IMAGERY SHOWS UPPER RIDGING
BUILDING ACROSS THE MISSISSIPPI RIVER VALLEY INTO THE LOCAL AREA IN
RESPONSE TO A DEEP CLOSED UPPER LOW ROTATING INTO THE DESERT
SOUTHWEST. THIS TROUGH IS SPLIT FROM A TROUGH THAT IS POSITIONED
OVER CENTRAL CANADA WITH A TROUGH AXIS SHIFTING TOWARDS WESTERN
SASKATCHEWAN. THESE TWO FEATURES WILL BE THE MAIN DRIVERS OF
EXPECTED RAINFALL THIS WEEKEND. AT THE SURFACE...A LARGE AREA OF
HIGH PRESSURE IS EXITING THE LOCAL AREA TO THE EAST. WEAK LOW
PRESSURE IS OVER SOUTHERN MANITOBA AND IS DRIFTING EASTWARD.
TONIGHT AND SATURDAY...QUIET WEATHER WILL CONTINUE TONIGHT WITH THE
UPPER RIDGE CRESTING THE AREA THIS EVENING. THE BIG SOUTHWEST
TROUGH WILL BE MOVING EASTWARD WITH HEIGHT FALLS AHEAD OF IT AND
BEHIND THE RIDGE ALLOWING LOW PRESSURE TO DEVELOP IN THE LEE OF
THE ROCKIES. A 50+KT LOW LEVEL JET WILL SET UP ACROSS THE PLAINS
RESULTING IN A STRONG PUSH OF HIGH THETA-E LOW LEVEL AIR ACROSS
THE SOUTHERN AND CENTRAL PLAINS. HIGH LEVEL MOISTURE WILL BE
SPREAD NORTHEASTWARD SUPPORTING AN INCREASE IN MID AND HIGH LEVEL
CLOUD COVER OVERNIGHT. THE PRESSURE GRADIENT WILL BE WEAK ACROSS
THE AREA EARLY BUT WILL TIGHTEN OVERNIGHT SO WINDS MAY DROP OFF
FOR A TIME EARLY BEFORE INCREASING SOMEWHAT OVERNIGHT. LOW TEMPS
WILL BE THE MAIN CHALLENGE AND MAY OCCUR DURING THE EVENING BUT
SOME WARMING MAY OCCUR LATE AS CLOUDS AND WINDS INCREASE AND WARM
ADVECTION IS UNDERWAY ALOFT. WILL GO AHEAD AND SHOW A STEADY OR
WARMING TREND OVERNIGHT. LIGHT PRECIP BECOMES A CONCERN BY
SATURDAY MORNING AS WAVES OF WARM ADVECTION BECOME MORE FOCUSED
AND MOISTURE DEEPENS. THIS IS WHERE TEMPS WILL BECOME CRITICAL
BECAUSE CHANCES FOR LIGHT PRECIP MAY BEGIN EARLY ENOUGH TO FALL AS
FREEZING RAIN. SIGNALS FOR PRECIP ARE NOT ALL THAT ORGANIZED UNTIL
SATURDAY AFTERNOON BUT WESTERN AREAS MAY HAVE DEEP ENOUGH MOISTURE
AND ENOUGH WARM ASCENT OCCURRING ALOFT TO SEE LIGHT RAIN...OR
FREEZING RAIN IF TEMPS START OUT BELOW FREEZING...BY LATE SATURDAY
MORNING. ANY FREEZING PRECIP WILL QUICKLY END AS TEMPS WARM WELL
ABOVE FREEZING BY EARLY AFTERNOON. PRECIP CHANCES WILL THEN EXPAND
EASTWARD...ESPECIALLY ACROSS THE NORTHERN CWA SATURDAY AFTERNOON
BUT CHANCES STILL LOOK RATHER LOW BUT STILL WORTH A MENTION GIVEN
STEADILY INCREASING DEEP LAYER MOISTURE /PRECIPITABLE WATER VALUES
REACH 0.75 INCHES OR SO BY LATE DAY/ AND WARM ADVECTION. SOUTH TO
SOUTHEAST WINDS WILL BECOME BREEZY WHICH WILL HELP HIGHS WARM INTO
LOW TO MID 40S NORTH AND MID TO UPPER 40S SOUTH. IT IS ALSO
IMPORTANT TO NOTE THAT DEW POINTS WILL BE ON THE RISE AS WELL
WHICH WILL COMBINE WITH THE STEADY WINDS AND MILD TEMPS TO PROVIDE
INCREASINGLY EFFICIENT SNOW MELT THROUGH THE AFTERNOON. MORE ON
THIS BELOW...
SATURDAY NIGHT AND SUNDAY...THE SOUTHWEST UPPER LOW WILL BE
LIFTING ACROSS THE SOUTHERN HIGH PLAINS AND PHASING WITH THE CENTRAL
CANADA UPPER TROUGH WHICH WILL BE SHARPENING AS IT PIVOTS
SOUTHEASTWARD. THE MAIN SURFACE LOW IS EXPECTED TO ORGANIZE IN
VICINITY OF THE SOUTHERN UPPER LOW ACROSS WESTERN KANSAS BY SATURDAY
EVENING WITH AN INVERTED TROUGH EXTENDING NORTHWARD INTO WESTERN
ONTARIO. GULF MOISTURE WILL CONTINUE TO STREAM NORTHWARD AHEAD OF
THE LOW AS 60KT LOW LEVEL JET SPREADS ACROSS
MISSOURI...ILLINOIS...AND LAKE MICHIGAN LATER SATURDAY EVENING.
PRECIPITABLE WATER VALUES WILL FURTHER SURGE REACHING THE 1 TO
PERHAPS 1.25 INCH RANGE WHICH WILL COMBINE WITH INCREASED ASCENT TO
PRODUCE WIDESPREAD RAIN ACROSS THE MID-MISSISSIPPI RIVER VALLEY
WHICH WILL THEN SPREAD EASTWARD DURING THE EVENING AND OVERNIGHT
HOURS. THE UPPER LOW WILL BE TO THE WEST OF THE AREA BY SUNDAY
MORNING WHICH WILL LIKELY BRING A DRY SLOT INTO THE AREA SOMETIME
SUNDAY MORNING. INSTABILITY DOES INCREASE AS WELL...POTENTIALLY WITH
ENOUGH ELEVATED INSTABILITY TO SUPPORT SOME THUNDER POTENTIAL ON THE
LEADING EDGE OF THE DRY SLOT. FURTHERMORE...SOME MINIMAL SURFACE
INSTABILITY COULD DEVELOP AS WELL WHICH WOULD POSE AN ADDITIONAL
THUNDER THREAT...ESPECIALLY ALONG THE APPROACHING COLD FRONT WHICH
WILL CROSS THE AREA LATER IN THE DAY. HOWEVER...THE DEEPER DRY AIR
OF THE DRY SLOT MAY PRECLUDE MUCH IF ANY DEVELOPMENT ALONG THE FRONT
IF SURFACE BASED INSTABILITY DOES IN FACT DEVELOP. STILL TOO EARLY
TO HAVE ANY HIGH DEGREE OF CONFIDENCE IN THUNDER POTENTIAL BUT FEEL
THIS BEARS WATCHING GIVEN THE HIGH DEGREE OF DEEP LAYER WIND SHEAR
AND FAIRLY STRONG LOW LEVEL WIND FIELD. HIGH TEMPS SUNDAY LOOK TO
RANGE FROM THE MID 40S NORTHWEST TO THE MID 50S SOUTHEAST.
PRECIP AMOUNTS/FLOODING POTENTIAL...FORECAST GUIDANCE IS IN PRETTY
GOOD AGREEMENT WITH THE TRACK OF LOW LEVEL FEATURES BUT DO DIFFER
IN THE PLACEMENT OF OTHER FEATURES SUCH AS THE PATH OF THE UPPER
JET CORE. QPF OUTPUT DOES DIFFER SOMEWHAT AS A RESULT...ESPECIALLY
IN PLACEMENT OF HEAVIEST VALUES. ARRIVAL TIMING MAY ALSO NEED
ADJUSTMENT WITH SOME GUIDANCE BEING SLOWER BUT RIGHT NOW THE
DIFFERENCES ARE ON THE ORDER OF A FEW HOURS. THE WESTERN AND
NORTHERN CWA CONTINUES TO LOOK TO HAVE THE BEST CHANCE AT
RECEIVING PEAK RAINFALL AMOUNTS...OR ROUGHLY FROM CHICAGO TO
PONTIAC AND POINTS WEST BUT THE ENTIRE CWA DOES LOOK TO SEE
RAINFALL. GIVEN THE PRECIPITABLE WATER VALUES AND DURATION OF
FORCING...AMOUNTS OF 0.75-1.00 INCHES ARE PLAUSIBLE IN THE NORTH
AND WEST WITH LESSER AMOUNTS SOUTHEAST. IF CONVECTION CAN DEVELOP
SUNDAY MORNING THEN AMOUNTS WOULD BE HIGHER IN SPOTS BUT IT IS
POSSIBLE THAT THE BEST CHANCE FOR CONVECTION COULD END UP BEING
ACROSS THE SOUTHERN/EASTERN CWA GIVEN THE LIKELY TRACK OF THE DRY
SLOT AND ARRIVAL OF INSTABILITY. SO CONFIDENCE IN SPECIFIC AMOUNTS
AND WHERE THEY OCCUR IS STILL LIMITED. HOWEVER...EVEN SOMEWHAT
LOWER AMOUNTS THAN THOSE ABOVE ARE STILL A CONCERN GIVEN THE
AMOUNT OF WATER IN THE CURRENT SNOW PACK. REFERENCE HYDROLOGY
SECTION BELOW AND ESFLOT PRODUCT FOR MORE DETAILS.
SUNDAY NIGHT AND MONDAY...TIMING DIFFERENCES BECOME MORE CRITICAL AS
THE SYSTEM DEPARTS SUNDAY NIGHT AND MONDAY. IN TERMS OF FRONTAL
TIMING...THERE IS GOOD AGREEMENT ON HAVING THE COLD FRONT SWEEP
ACROSS THE AREA SUNDAY AFTERNOON WHICH ALLOWS COLDER AIR TO
ARRIVE...BUT THE SPEED WITH WHICH IT ARRIVES IS NOT QUITE CLEAR. THE
ECMWF/GEM REMAIN SLOWER WITH THE PASSAGE OF THE UPPER TROUGH AXIS
DELAYING THE ARRIVAL OF COLDEST AIR...AS WELL AS THE ATTENDANT
DEFORMATION FORCING HOLDING IT OFF UNTIL CLOSER TO MONDAY MORNING.
THE NAM AND GFS ARE FASTER WITH THE UPPER TROUGH AND ARRIVAL OF COLD
AIR. THIS WILL PLAY HAVOC WITH PRECIP TIMING AND TYPE BEHIND THE
FRONT INTO MONDAY MORNING. WILL NEED TO MONITOR THIS PERIOD AS THERE
IS AT LEAST SOME SUPPORT FOR MEASURABLE PRECIP MONDAY.
MDB
LONG TERM...MONDAY NIGHT THROUGH FRIDAY...
THE EXTENDED PERIOD WILL FEATURE A FAIRLY PROGRESSIVE NORTHWEST TO
PERHAPS ZONAL FLOW WITH SEVERAL WEAK SYSTEMS TO AFFECT PART OF THE
REGION/GREAT LAKES. TIMING ANY OF THESE FEATURES IS SOMEWHAT
DIFFICULT AS THEIR STRENGTH/LOCATION CONTINUES TO FLUCTUATE FROM
RUN TO RUN AS WELL AS FROM MODEL TO MODEL. WHILE THERE WILL BE A
FEW CHANCES FOR PRECIP...WILL CONTINUE WITH MAINLY A DRY FORECAST
DUE TO LOW CONFIDENCE THOUGH HAVE INCLUDED A SLIGHT CHANCE OF
SHOWERS ON FRIDAY AS THERE HAS BEEN SOME CONTINUITY DURING THIS TIME
PERIOD. SHOULD PRECIP CHANCES/TRENDS INCREASE...PRECIP TYPE WILL
BECOME A CONCERN DEPENDING ON TIME OF DAY.
TEMPERATURES ARE EQUALLY CHALLENGING...DEPENDING ON THE TIMING OF
THESE FEATURES AND THE EXTENT OF COLD AIR THEY BRING WITH THEM.
ECMWF HAD BEEN FAIRLY CONSISTENT WITH A PUSH OF COLDER AIR THURSDAY
INTO FRIDAY WHICH IS NOW GONE WHILE THE GFS IS NOW MUCH COLDER. HAVE
TRENDED MIDDLE OF THE ROAD WITH TEMPS AND GIVEN MID MARCH SUNSHINE...
LACK OF ANY SIGNIFICANT COLD AIR PUSH WOULD SUPPORT TEMPS NEAR
SEASONAL NORMALS.
CMS
&&
.HYDROLOGY...
234 PM CST
SOME AREAS OF THE FORECAST AREA MAY SEE 0.75-1.00 INCHES
OF RAINFALL FROM SATURDAY THROUGH SUNDAY...WITH THE BULK EXPECTED
SATURDAY EVENING/NIGHT. AT THIS POINT...THESE RAINFALL AMOUNTS ARE
EXPECTED GENERALLY WEST OF A LINE FROM CHICAGO TO PONTIAC WITH
LESSER AMOUNTS SOUTHEAST BUT THERE IS SOME OPPORTUNITY FOR THE
LOCATION TO NEED ADJUSTMENT. IN ADDITION...SOME CONVECTIVE
RAINFALL IS POSSIBLE WHICH COULD RESULT IN LOCALLY HIGHER AMOUNTS.
OBSERVED SNOW CORE WATER EQUIVALENTS RANGE FROM AROUND AN INCH TO
AROUND 2.5 INCHES WHERE THE DEEPEST SNOW EXISTS...MAINLY NORTH OF
INTERSTATE 80. FROST DEPTH REMAINS IN THE 6 TO 10 INCH RANGE. THE
EXPECTATION IS THAT THE SNOW WILL MELT AND RUNOFF WILL BE REALIZED
BEFORE THE FROST MELTS SIGNIFICANTLY DUE TO THE INSULATING
EFFECTS OF THE SNOW PACK. SNOW MELT WILL COMMENCE BEFORE THE BULK
OF THE RAINFALL WHICH COULD ALLOW SOME OF THE RUNOFF INTO AREA
RIVERS AND STREAMS TO MAKE PROGRESS DOWNSTREAM BUT THIS WOULD
LIKELY BE MINIMAL. MOST MELT WILL LIKELY OCCUR WITH THE RAINFALL
SO RIVER RISES WILL OCCUR AND SOME RIVERS COULD EXCEED FLOOD STAGE
LATER SUNDAY/MONDAY. AREAL OVERLAND FLOODING IS A
POSSIBILITY...MAINLY IN LOW LYING AND POORLY DRAINED AREAS.
REFERENCE ESFLOT FOR ADDITIONAL INFORMATION.
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 06Z...
* CHANCE OF SOME LIGHT RAIN THIS AFTERNOON.
* RAIN AND FOG TIMING TONIGHT.
* MVFR CIGS AND VISIBILITY LIKELY AFTER 06 UTC SATURDAY NIGHT.
* IFR CIGS AND VISIBILITY POSSIBLE BY DAYBREAK ON SUNDAY MORNING.
* LLWS POSSIBLE SATURDAY NIGHT.
KJB
//DISCUSSION...UPDATED 06Z...
THE MAIN CONCERNS DURING THE PERIOD WILL BE WITH OUR NEXT STORM
SYSTEM...WHICH IS CURRENTLY TAKING SHAPE ACROSS THE FRONT RANGE OF
THE COLORADO ROCKIES. THIS SYSTEM IS ALREADY TRANSPORTING WARM AND
MOIST AIR NORTHWARD ACROSS THE PLAINS AND INTO THE MID MISSOURI
VALLEY WITH SCATTERED SHOWERS AND EVEN SOME THUNDERSTORMS ONGOING
ACROSS THIS REGION.
IT APPEARS SOME OF THESE SHOWERS MAY EFFECT KRFD AROUND
DAYBREAK...AND WITH TEMPERATURES POSSIBLY NEAR FREEZING...I OPTED TO
LEAVE THE -FZRA IN THE NEW TAF FROM 12-14 UTC THIS MORNING.
HOWEVER...I HAVE LOW CONFIDENCE IN THE FREEZING THREAT AS
TEMPERATURES MAY ACTUALLY JUMP ABOVE FREEZING PRIOR TO THE ONSET OF
THE PRECIPITATION. IN ADDITION...I AM NOT SURE HOW MUCH IF ANY PRECIP
WILL ACTUALLY FALL THIS MORNING. THERE IS STILL SOME DRY AIR IN THE
LOW LEVELS TO OVERCOME...AND IT APPEARS THAT CIGS WILL STILL BE AT
OR ABOVE 9000 FEET THROUGH 15 UTC. WITH THIS IN MIND...WE MAY NOT
SEE MORE THAN A FEW SPRINKLES DURING THE EARLY MORNING HOURS AT
KRFD.
IT APPEARS MOST OF THE DAY PRIOR TO 20 UTC WILL BE DRY. AFTER 20 UTC
WE COULD GET ANOTHER BATCH OF LIGHT RAIN ACROSS THE TAF SITES. THIS
ALSO APPEARS AS THOUGH IT WILL BE RATHER LIGHT...AND I HAVE OPTED TO
KEEP THE PROB 30 GROUP GOING FOR THIS ACTIVITY. I
DID...HOWEVER...TRIM THE END TIME OF THE PROB 30 GROUP TO 01 UTC AS
IT APPEARS THERE WILL BE QUITE A BIT OF DRY TIME THIS EVENING AHEAD
OF THE MAIN BATCH OF RAIN.
RAIN SHOULD ONSET AROUND OR SHORTLY AFTER 03 UTC THIS EVENING AT
KRFD AND AFTER 06 UTC AT THE EASTERN TERMINALS AS THE MAIN STORM
SYSTEM APPROACHES THE AREA. IT APPEARS THE RAIN WILL BE MODERATE AT
TIMES WITH CIGS GRADUALLY LOWERING INTO THE IFR CATEGORY BY EARLY
SUNDAY. VISIBILITIES WILL ALSO BE DEGRADING INTO AT LEAST THE
MVFR RANGE IN RAIN AND FOG. LOW CLOUDS AND FOG LOOK TO CONTINUE INTO
THE DAY ON SUNDAY AS THE SURFACE LOW MOVES OVERHEAD AND SURFACE
DEW POINTS PEAK IN THE LOWER TO MIDDLE 40S.
THERE IS ALSO A CHANCE OF LLWS SATURDAY NIGHT AS IT APPEARS THE A
SOUTHWESTERLY 50-55 LOW LEVEL JET WILL DEVELOP AROUND 2,000 FT AGL.
SURFACE WINDS DURING THIS TIME ARE EXPECTED TO BE AROUND 10 KT OUT
OF THE SOUTH. I HAVE OPTED NOT TO ADD THIS TO THE NEW TAF...BUT IT
MAY NEED TO BE ADDED AT A LATER TIME IF THESE CONDITIONS APPEAR TO BE
SETTING UP.
KJB
//ORD AND MDW CONFIDENCE...UPDATED 06Z...
* LOW CONFIDENCE ON ANY LIGHT RAIN AFFECTING THE TERMINALS THIS
AFTERNOON.
* MEDIUM TO HIGH CONFIDENCE IN RAIN AND FOG REDUCING VISIBILITIES
UNDER 4 MILES LATER SUNDAY NIGHT AFTER 06 UTC.
* MEDIUM CONFIDENCE IN IFR CIGS TOWARDS DAYBREAK SUNDAY.
* LOW TO MEDIUM CONFIDENCE IN LLWS SATURDAY NIGHT.
KJB
//OUTLOOK FOR ORD/MDW FOR 12Z SUNDAY-12Z FRIDAY...UPDATED 00Z...
SUNDAY...RAIN AND FOG WITH LIKELY IFR. A CHANCE FOR A MIX WITH
SNOW DURING THE NIGHT.
MONDAY...SLIGHT CHANCE OF RAIN AND SNOW WITH MVFR.
TUESDAY-THURSDAY...VFR.
MTF
&&
.MARINE...
228 AM CST
A STORM SYSTEM...CURRENTLY TAKING SHAPE ACROSS THE FRONT RANGE OF
THE COLORADO ROCKIES...WILL SPLIT OFF INTO TWO SYSTEMS. ONE WILL
RACE NORTHEASTWARD ACROSS ONTARIO BY SUNDAY...WHILE THE SECOND SYSTEM
MOVES TOWARDS THE SOUTHERN END OF LAKE MICHIGAN BY SUNDAY EVENING.
THIS SECOND SYSTEM LOOKS TO HAVE A LARGE IMPACT ON THE WINDS OVER
THE LAKE THROUGH THE WEEKEND.
SOUTHERLY WINDS WILL OCCUR TODAY AND TONIGHT...UP AROUND 25 KT
AHEAD OF THIS SYSTEM. THEN AS THE SURFACE LOW APPROACHES THE LAKE ON
SUNDAY...THE WINDS WILL BECOME NORTH-NORTHEASTERLY AND INCREASE UP
AROUND 30 KT...ESPECIALLY ACROSS THE NORTHERN END OF THE LAKE.
GALE FORCE WINDS ARE QUITE POSSIBLE WITH THIS SYSTEM...BUT
UNCERTAINTIES REMAIN AS TO THE EXACT TRACK OF THIS SYSTEM...AND
HENCE WHERE THE STRONGEST WINDS WILL BE.
ONCE THIS LOW PASSES OVER THE LAKE...A PERIOD OF NORTHWESTERLY WINDS
OF 25 TO 30 KT LOOKS LIKELY INTO AT LEAST MONDAY. HOWEVER...THESE
NORTHWESTERLY WINDS COULD CONTINUE INTO MIDWEEK AS IT APPEARS A
WEAK CLIPPER SYSTEM MAY MOVE ACROSS THE LAKE SOMETIME ON TUESDAY OR
TUESDAY EVENING.
KJB
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
1227 AM CST SAT MAR 9 2013
.DISCUSSION...
924 PM CST
NO REAL BIG CHANGES TO GOING FORECAST TONIGHT...WITH ONLY MINOR
EDITS TO POP/WX FOR AREAS ACROSS NORTHWEST ILLINOIS.
LATEST SATELLITE IMAGERY DEPICTING MID/UPPER LEVEL CLOUD COVER
CONTINUING TO STREAM NORTHEAST ACROSS THE REGION THIS EVENING...AS
SOUTHWESTERLY FLOW CONTINUES OUT AHEAD OF AN APPROACHING LONGWAVE
TROUGH OVER THE WESTERN CONUS. THIS IS USHERING IN A WARMER AND
MORE MOIST ENVIRONMENT WITH LATEST RAP ANALYSIS DEPICTING STRONG
WAA OCCURRING ACROSS MUCH OF THE PLAINS...AND CAN BE NOTED VIA THE
ABUNDANCE OF CLOUD COVER AS WELL AS THE WIDESPREAD PRECIP SHIELD
IN THIS LOCATION. ALTHOUGH THE STRONGEST WAA WILL REMAIN JUST TO
THE WEST OF THE CWA...LATEST SHORT TERM GUIDANCE IS INDICATING
THAT SOME LIGHT PRECIP DEVELOPMENT COULD OCCUR ACROSS NORTHWEST
ILLINOIS TONIGHT AS THIS WAA WING CONTINUES TO LIFT
NORTH/NORTHEAST. PRECIP DEVELOPMENT LATE TONIGHT ACROSS AREAS
ALONG AND WEST OF INTERSTATE 39 DOES SEEM REASONABLE WITH THIS
BETTER FORCING ALREADY INCHING CLOSER TO THE CWA. ALTHOUGH THIS
FORCING WILL REMAIN RATHER WEAK...IT MAY BE ENOUGH OF A PERSISTENT
FEATURE TO OVERCOME SOME DRIER AIR IN PLACE. THERMAL PROFILES WILL
SUPPORT PRECIP OF THE LIQUID TYPE...BUT WITH THE POSSIBILITY OF A
BRIEF WINDOW OF LIGHT FREEZING RAIN. ALTHOUGH...WARMING TONIGHT
SHOULD MITIGATE ANY OVERALL FREEZING RAIN POTENTIAL WITH SURFACE
TEMPERATURES EXPECTED TO BE HOVERING AROUND FREEZING IF NOT
BEGINNING TO RISE JUST ABOVE BY THE TIME THIS PRECIP ARRIVES. SO
HAVE MADE MENTION OF A SLIGHT CHANCE OF LIGHT RAIN/LIGHT FREEZING
RAIN FOR LATE TONIGHT INTO EARLY SATURDAY MORNING BEFORE
TEMPERATURES CONTINUE TO RISE THROUGH MID SATURDAY MORNING WITH
ONLY RAIN THEN EXPECTED.
RODRIGUEZ
//PREV DISCUSSION...
234 PM CST
THE AREA WILL QUICKLY SHIFT FROM WINTER TO SPRING WEATHER THIS
WEEKEND WITH EXPECTED RAINFALL/SNOW MELT WITH WARMING TEMPERATURES
POSING A FLOOD THREAT...WITH THUNDERSTORMS NOT OUT OF THE QUESTION
BY SUNDAY. UPS AND DOWNS IN TEMPERATURES ARE EXPECTED NEXT WEEK WITH
A SERIES OF WEAKER SYSTEMS BRINGING PERIODIC LOW CHANCES FOR
PRECIPITATION.
SYNOPSIS...EARLY AFTERNOON WATER VAPOR IMAGERY SHOWS UPPER RIDGING
BUILDING ACROSS THE MISSISSIPPI RIVER VALLEY INTO THE LOCAL AREA IN
RESPONSE TO A DEEP CLOSED UPPER LOW ROTATING INTO THE DESERT
SOUTHWEST. THIS TROUGH IS SPLIT FROM A TROUGH THAT IS POSITIONED
OVER CENTRAL CANADA WITH A TROUGH AXIS SHIFTING TOWARDS WESTERN
SASKATCHEWAN. THESE TWO FEATURES WILL BE THE MAIN DRIVERS OF
EXPECTED RAINFALL THIS WEEKEND. AT THE SURFACE...A LARGE AREA OF
HIGH PRESSURE IS EXITING THE LOCAL AREA TO THE EAST. WEAK LOW
PRESSURE IS OVER SOUTHERN MANITOBA AND IS DRIFTING EASTWARD.
TONIGHT AND SATURDAY...QUIET WEATHER WILL CONTINUE TONIGHT WITH THE
UPPER RIDGE CRESTING THE AREA THIS EVENING. THE BIG SOUTHWEST
TROUGH WILL BE MOVING EASTWARD WITH HEIGHT FALLS AHEAD OF IT AND
BEHIND THE RIDGE ALLOWING LOW PRESSURE TO DEVELOP IN THE LEE OF
THE ROCKIES. A 50+KT LOW LEVEL JET WILL SET UP ACROSS THE PLAINS
RESULTING IN A STRONG PUSH OF HIGH THETA-E LOW LEVEL AIR ACROSS
THE SOUTHERN AND CENTRAL PLAINS. HIGH LEVEL MOISTURE WILL BE
SPREAD NORTHEASTWARD SUPPORTING AN INCREASE IN MID AND HIGH LEVEL
CLOUD COVER OVERNIGHT. THE PRESSURE GRADIENT WILL BE WEAK ACROSS
THE AREA EARLY BUT WILL TIGHTEN OVERNIGHT SO WINDS MAY DROP OFF
FOR A TIME EARLY BEFORE INCREASING SOMEWHAT OVERNIGHT. LOW TEMPS
WILL BE THE MAIN CHALLENGE AND MAY OCCUR DURING THE EVENING BUT
SOME WARMING MAY OCCUR LATE AS CLOUDS AND WINDS INCREASE AND WARM
ADVECTION IS UNDERWAY ALOFT. WILL GO AHEAD AND SHOW A STEADY OR
WARMING TREND OVERNIGHT. LIGHT PRECIP BECOMES A CONCERN BY
SATURDAY MORNING AS WAVES OF WARM ADVECTION BECOME MORE FOCUSED
AND MOISTURE DEEPENS. THIS IS WHERE TEMPS WILL BECOME CRITICAL
BECAUSE CHANCES FOR LIGHT PRECIP MAY BEGIN EARLY ENOUGH TO FALL AS
FREEZING RAIN. SIGNALS FOR PRECIP ARE NOT ALL THAT ORGANIZED UNTIL
SATURDAY AFTERNOON BUT WESTERN AREAS MAY HAVE DEEP ENOUGH MOISTURE
AND ENOUGH WARM ASCENT OCCURRING ALOFT TO SEE LIGHT RAIN...OR
FREEZING RAIN IF TEMPS START OUT BELOW FREEZING...BY LATE SATURDAY
MORNING. ANY FREEZING PRECIP WILL QUICKLY END AS TEMPS WARM WELL
ABOVE FREEZING BY EARLY AFTERNOON. PRECIP CHANCES WILL THEN EXPAND
EASTWARD...ESPECIALLY ACROSS THE NORTHERN CWA SATURDAY AFTERNOON
BUT CHANCES STILL LOOK RATHER LOW BUT STILL WORTH A MENTION GIVEN
STEADILY INCREASING DEEP LAYER MOISTURE /PRECIPITABLE WATER VALUES
REACH 0.75 INCHES OR SO BY LATE DAY/ AND WARM ADVECTION. SOUTH TO
SOUTHEAST WINDS WILL BECOME BREEZY WHICH WILL HELP HIGHS WARM INTO
LOW TO MID 40S NORTH AND MID TO UPPER 40S SOUTH. IT IS ALSO
IMPORTANT TO NOTE THAT DEW POINTS WILL BE ON THE RISE AS WELL
WHICH WILL COMBINE WITH THE STEADY WINDS AND MILD TEMPS TO PROVIDE
INCREASINGLY EFFICIENT SNOW MELT THROUGH THE AFTERNOON. MORE ON
THIS BELOW...
SATURDAY NIGHT AND SUNDAY...THE SOUTHWEST UPPER LOW WILL BE
LIFTING ACROSS THE SOUTHERN HIGH PLAINS AND PHASING WITH THE CENTRAL
CANADA UPPER TROUGH WHICH WILL BE SHARPENING AS IT PIVOTS
SOUTHEASTWARD. THE MAIN SURFACE LOW IS EXPECTED TO ORGANIZE IN
VICINITY OF THE SOUTHERN UPPER LOW ACROSS WESTERN KANSAS BY SATURDAY
EVENING WITH AN INVERTED TROUGH EXTENDING NORTHWARD INTO WESTERN
ONTARIO. GULF MOISTURE WILL CONTINUE TO STREAM NORTHWARD AHEAD OF
THE LOW AS 60KT LOW LEVEL JET SPREADS ACROSS
MISSOURI...ILLINOIS...AND LAKE MICHIGAN LATER SATURDAY EVENING.
PRECIPITABLE WATER VALUES WILL FURTHER SURGE REACHING THE 1 TO
PERHAPS 1.25 INCH RANGE WHICH WILL COMBINE WITH INCREASED ASCENT TO
PRODUCE WIDESPREAD RAIN ACROSS THE MID-MISSISSIPPI RIVER VALLEY
WHICH WILL THEN SPREAD EASTWARD DURING THE EVENING AND OVERNIGHT
HOURS. THE UPPER LOW WILL BE TO THE WEST OF THE AREA BY SUNDAY
MORNING WHICH WILL LIKELY BRING A DRY SLOT INTO THE AREA SOMETIME
SUNDAY MORNING. INSTABILITY DOES INCREASE AS WELL...POTENTIALLY WITH
ENOUGH ELEVATED INSTABILITY TO SUPPORT SOME THUNDER POTENTIAL ON THE
LEADING EDGE OF THE DRY SLOT. FURTHERMORE...SOME MINIMAL SURFACE
INSTABILITY COULD DEVELOP AS WELL WHICH WOULD POSE AN ADDITIONAL
THUNDER THREAT...ESPECIALLY ALONG THE APPROACHING COLD FRONT WHICH
WILL CROSS THE AREA LATER IN THE DAY. HOWEVER...THE DEEPER DRY AIR
OF THE DRY SLOT MAY PRECLUDE MUCH IF ANY DEVELOPMENT ALONG THE FRONT
IF SURFACE BASED INSTABILITY DOES IN FACT DEVELOP. STILL TOO EARLY
TO HAVE ANY HIGH DEGREE OF CONFIDENCE IN THUNDER POTENTIAL BUT FEEL
THIS BEARS WATCHING GIVEN THE HIGH DEGREE OF DEEP LAYER WIND SHEAR
AND FAIRLY STRONG LOW LEVEL WIND FIELD. HIGH TEMPS SUNDAY LOOK TO
RANGE FROM THE MID 40S NORTHWEST TO THE MID 50S SOUTHEAST.
PRECIP AMOUNTS/FLOODING POTENTIAL...FORECAST GUIDANCE IS IN PRETTY
GOOD AGREEMENT WITH THE TRACK OF LOW LEVEL FEATURES BUT DO DIFFER
IN THE PLACEMENT OF OTHER FEATURES SUCH AS THE PATH OF THE UPPER
JET CORE. QPF OUTPUT DOES DIFFER SOMEWHAT AS A RESULT...ESPECIALLY
IN PLACEMENT OF HEAVIEST VALUES. ARRIVAL TIMING MAY ALSO NEED
ADJUSTMENT WITH SOME GUIDANCE BEING SLOWER BUT RIGHT NOW THE
DIFFERENCES ARE ON THE ORDER OF A FEW HOURS. THE WESTERN AND
NORTHERN CWA CONTINUES TO LOOK TO HAVE THE BEST CHANCE AT
RECEIVING PEAK RAINFALL AMOUNTS...OR ROUGHLY FROM CHICAGO TO
PONTIAC AND POINTS WEST BUT THE ENTIRE CWA DOES LOOK TO SEE
RAINFALL. GIVEN THE PRECIPITABLE WATER VALUES AND DURATION OF
FORCING...AMOUNTS OF 0.75-1.00 INCHES ARE PLAUSIBLE IN THE NORTH
AND WEST WITH LESSER AMOUNTS SOUTHEAST. IF CONVECTION CAN DEVELOP
SUNDAY MORNING THEN AMOUNTS WOULD BE HIGHER IN SPOTS BUT IT IS
POSSIBLE THAT THE BEST CHANCE FOR CONVECTION COULD END UP BEING
ACROSS THE SOUTHERN/EASTERN CWA GIVEN THE LIKELY TRACK OF THE DRY
SLOT AND ARRIVAL OF INSTABILITY. SO CONFIDENCE IN SPECIFIC AMOUNTS
AND WHERE THEY OCCUR IS STILL LIMITED. HOWEVER...EVEN SOMEWHAT
LOWER AMOUNTS THAN THOSE ABOVE ARE STILL A CONCERN GIVEN THE
AMOUNT OF WATER IN THE CURRENT SNOW PACK. REFERENCE HYDROLOGY
SECTION BELOW AND ESFLOT PRODUCT FOR MORE DETAILS.
SUNDAY NIGHT AND MONDAY...TIMING DIFFERENCES BECOME MORE CRITICAL AS
THE SYSTEM DEPARTS SUNDAY NIGHT AND MONDAY. IN TERMS OF FRONTAL
TIMING...THERE IS GOOD AGREEMENT ON HAVING THE COLD FRONT SWEEP
ACROSS THE AREA SUNDAY AFTERNOON WHICH ALLOWS COLDER AIR TO
ARRIVE...BUT THE SPEED WITH WHICH IT ARRIVES IS NOT QUITE CLEAR. THE
ECMWF/GEM REMAIN SLOWER WITH THE PASSAGE OF THE UPPER TROUGH AXIS
DELAYING THE ARRIVAL OF COLDEST AIR...AS WELL AS THE ATTENDANT
DEFORMATION FORCING HOLDING IT OFF UNTIL CLOSER TO MONDAY MORNING.
THE NAM AND GFS ARE FASTER WITH THE UPPER TROUGH AND ARRIVAL OF COLD
AIR. THIS WILL PLAY HAVOC WITH PRECIP TIMING AND TYPE BEHIND THE
FRONT INTO MONDAY MORNING. WILL NEED TO MONITOR THIS PERIOD AS THERE
IS AT LEAST SOME SUPPORT FOR MEASURABLE PRECIP MONDAY.
MDB
LONG TERM...MONDAY NIGHT THROUGH FRIDAY...
THE EXTENDED PERIOD WILL FEATURE A FAIRLY PROGRESSIVE NORTHWEST TO
PERHAPS ZONAL FLOW WITH SEVERAL WEAK SYSTEMS TO AFFECT PART OF THE
REGION/GREAT LAKES. TIMING ANY OF THESE FEATURES IS SOMEWHAT
DIFFICULT AS THEIR STRENGTH/LOCATION CONTINUES TO FLUCTUATE FROM
RUN TO RUN AS WELL AS FROM MODEL TO MODEL. WHILE THERE WILL BE A
FEW CHANCES FOR PRECIP...WILL CONTINUE WITH MAINLY A DRY FORECAST
DUE TO LOW CONFIDENCE THOUGH HAVE INCLUDED A SLIGHT CHANCE OF
SHOWERS ON FRIDAY AS THERE HAS BEEN SOME CONTINUITY DURING THIS TIME
PERIOD. SHOULD PRECIP CHANCES/TRENDS INCREASE...PRECIP TYPE WILL
BECOME A CONCERN DEPENDING ON TIME OF DAY.
TEMPERATURES ARE EQUALLY CHALLENGING...DEPENDING ON THE TIMING OF
THESE FEATURES AND THE EXTENT OF COLD AIR THEY BRING WITH THEM.
ECMWF HAD BEEN FAIRLY CONSISTENT WITH A PUSH OF COLDER AIR THURSDAY
INTO FRIDAY WHICH IS NOW GONE WHILE THE GFS IS NOW MUCH COLDER. HAVE
TRENDED MIDDLE OF THE ROAD WITH TEMPS AND GIVEN MID MARCH SUNSHINE...
LACK OF ANY SIGNIFICANT COLD AIR PUSH WOULD SUPPORT TEMPS NEAR
SEASONAL NORMALS.
CMS
&&
.HYDROLOGY...
234 PM CST
SOME AREAS OF THE FORECAST AREA MAY SEE 0.75-1.00 INCHES
OF RAINFALL FROM SATURDAY THROUGH SUNDAY...WITH THE BULK EXPECTED
SATURDAY EVENING/NIGHT. AT THIS POINT...THESE RAINFALL AMOUNTS ARE
EXPECTED GENERALLY WEST OF A LINE FROM CHICAGO TO PONTIAC WITH
LESSER AMOUNTS SOUTHEAST BUT THERE IS SOME OPPORTUNITY FOR THE
LOCATION TO NEED ADJUSTMENT. IN ADDITION...SOME CONVECTIVE
RAINFALL IS POSSIBLE WHICH COULD RESULT IN LOCALLY HIGHER AMOUNTS.
OBSERVED SNOW CORE WATER EQUIVALENTS RANGE FROM AROUND AN INCH TO
AROUND 2.5 INCHES WHERE THE DEEPEST SNOW EXISTS...MAINLY NORTH OF
INTERSTATE 80. FROST DEPTH REMAINS IN THE 6 TO 10 INCH RANGE. THE
EXPECTATION IS THAT THE SNOW WILL MELT AND RUNOFF WILL BE REALIZED
BEFORE THE FROST MELTS SIGNIFICANTLY DUE TO THE INSULATING
EFFECTS OF THE SNOW PACK. SNOW MELT WILL COMMENCE BEFORE THE BULK
OF THE RAINFALL WHICH COULD ALLOW SOME OF THE RUNOFF INTO AREA
RIVERS AND STREAMS TO MAKE PROGRESS DOWNSTREAM BUT THIS WOULD
LIKELY BE MINIMAL. MOST MELT WILL LIKELY OCCUR WITH THE RAINFALL
SO RIVER RISES WILL OCCUR AND SOME RIVERS COULD EXCEED FLOOD STAGE
LATER SUNDAY/MONDAY. AREAL OVERLAND FLOODING IS A
POSSIBILITY...MAINLY IN LOW LYING AND POORLY DRAINED AREAS.
REFERENCE ESFLOT FOR ADDITIONAL INFORMATION.
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 06Z...
* CHANCE OF SOME LIGHT RAIN THIS AFTERNOON.
* RAIN AND FOG TIMING TONIGHT.
* MVFR CIGS AND VISIBILITY LIKELY AFTER 06 UTC SATURDAY NIGHT.
* IFR CIGS AND VISIBILITY POSSIBLE BY DAYBREAK ON SUNDAY MORNING.
* LLWS POSSIBLE SATURDAY NIGHT.
KJB
//DISCUSSION...UPDATED 06Z...
THE MAIN CONCERNS DURING THE PERIOD WILL BE WITH OUR NEXT STORM
SYSTEM...WHICH IS CURRENTLY TAKING SHAPE ACROSS THE FRONT RANGE OF
THE COLORADO ROCKIES. THIS SYSTEM IS ALREADY TRANSPORTING WARM AND
MOIST AIR NORTHWARD ACROSS THE PLAINS AND INTO THE MID MISSOURI
VALLEY WITH SCATTERED SHOWERS AND EVEN SOME THUNDERSTORMS ONGOING
ACROSS THIS REGION.
IT APPEARS SOME OF THESE SHOWERS MAY EFFECT KRFD AROUND
DAYBREAK...AND WITH TEMPERATURES POSSIBLY NEAR FREEZING...I OPTED TO
LEAVE THE -FZRA IN THE NEW TAF FROM 12-14 UTC THIS MORNING.
HOWEVER...I HAVE LOW CONFIDENCE IN THE FREEZING THREAT AS
TEMPERATURES MAY ACTUALLY JUMP ABOVE FREEZING PRIOR TO THE ONSET OF
THE PRECIPITATION. IN ADDITION...I AM NOT SURE HOW MUCH IF ANY PRECIP
WILL ACTUALLY FALL THIS MORNING. THERE IS STILL SOME DRY AIR IN THE
LOW LEVELS TO OVERCOME...AND IT APPEARS THAT CIGS WILL STILL BE AT
OR ABOVE 9000 FEET THROUGH 15 UTC. WITH THIS IN MIND...WE MAY NOT
SEE MORE THAN A FEW SPRINKLES DURING THE EARLY MORNING HOURS AT
KRFD.
IT APPEARS MOST OF THE DAY PRIOR TO 20 UTC WILL BE DRY. AFTER 20 UTC
WE COULD GET ANOTHER BATCH OF LIGHT RAIN ACROSS THE TAF SITES. THIS
ALSO APPEARS AS THOUGH IT WILL BE RATHER LIGHT...AND I HAVE OPTED TO
KEEP THE PROB 30 GROUP GOING FOR THIS ACTIVITY. I
DID...HOWEVER...TRIM THE END TIME OF THE PROB 30 GROUP TO 01 UTC AS
IT APPEARS THERE WILL BE QUITE A BIT OF DRY TIME THIS EVENING AHEAD
OF THE MAIN BATCH OF RAIN.
RAIN SHOULD ONSET AROUND OR SHORTLY AFTER 03 UTC THIS EVENING AT
KRFD AND AFTER 06 UTC AT THE EASTERN TERMINALS AS THE MAIN STORM
SYSTEM APPROACHES THE AREA. IT APPEARS THE RAIN WILL BE MODERATE AT
TIMES WITH CIGS GRADUALLY LOWERING INTO THE IFR CATEGORY BY EARLY
SUNDAY. VISIBILITIES WILL ALSO BE DEGRADING INTO AT LEAST THE
MVFR RANGE IN RAIN AND FOG. LOW CLOUDS AND FOG LOOK TO CONTINUE INTO
THE DAY ON SUNDAY AS THE SURFACE LOW MOVES OVERHEAD AND SURFACE
DEW POINTS PEAK IN THE LOWER TO MIDDLE 40S.
THERE IS ALSO A CHANCE OF LLWS SATURDAY NIGHT AS IT APPEARS THE A
SOUTHWESTERLY 50-55 LOW LEVEL JET WILL DEVELOP AROUND 2,000 FT AGL.
SURFACE WINDS DURING THIS TIME ARE EXPECTED TO BE AROUND 10 KT OUT
OF THE SOUTH. I HAVE OPTED NOT TO ADD THIS TO THE NEW TAF...BUT IT
MAY NEED TO BE ADDED AT A LATER TIME IF THESE CONDITIONS APPEAR TO BE
SETTING UP.
KJB
//ORD AND MDW CONFIDENCE...UPDATED 06Z...
* LOW CONFIDENCE ON ANY LIGHT RAIN AFFECTING THE TERMINALS THIS
AFTERNOON.
* MEDIUM TO HIGH CONFIDENCE IN RAIN AND FOG REDUCING VISIBILITIES
UNDER 4 MILES LATER SUNDAY NIGHT AFTER 06 UTC.
* MEDIUM CONFIDENCE IN IFR CIGS TOWARDS DAYBREAK SUNDAY.
* LOW TO MEDIUM CONFIDENCE IN LLWS SATURDAY NIGHT.
KJB
//OUTLOOK FOR ORD/MDW FOR 12Z SUNDAY-12Z FRIDAY...UPDATED 00Z...
SUNDAY...RAIN AND FOG WITH LIKELY IFR. A CHANCE FOR A MIX WITH
SNOW DURING THE NIGHT.
MONDAY...SLIGHT CHANCE OF RAIN AND SNOW WITH MVFR.
TUESDAY-THURSDAY...VFR.
MTF
&&
.MARINE...
125 PM CST
THE HIGH PRESSURE THAT BROUGHT LIGHT AND VARIABLE WINDS TO LAKE
MICHIGAN HAS MOVED EAST OF THE LAKE AND WINDS HAVE BECOME
SOUTHERLY. AS DEEPENING LOW PRESSURE MOVES OUT OF THE ROCKIES AND
INTO THE SOUTHERN PLAINS...WHILE THE HIGH MOVES SLOWLY TO THE
EAST...THE GENERALLY SOUTHERLY WINDS WILL STRENGTHEN THROUGH THE
WEEKEND. BY SATURDAY EVENING...THE HIGH WILL MOVE TO THE EASTERN
SEABOARD WHILE THE LOW PRESSURE MOVER THE SOUTH HIGH PLAINS DEEPENS
AND A TROUGH OF LOW PRESSURE ELONGATES TO ANOTHER...WEAKER LOW JUST
NORTH OF MINNESOTA. SOUTHERLY WINDS WILL INCREASE TO AROUND 30 KT
AS THE TROUGH OF LOW PRESSURE AND AN ASSOCIATED COLD FRONT APPROACH
THE LAKE. THE COLD FRONT IS EXPECTED TO SWEEP ACROSS THE LAKE
SUNDAY...WITH WINDS QUICKLY VEERING TO NORTHERLY. WITH HIGH
PRESSURE QUICKLY BUILDING IN ACROSS THE LAKE BEHIND THE COLD
FRONT...THE NORTHERLY WINDS WILL ONLY BRIEFLY INCREASE TO AROUND 25
KT SUNDAY NIGHT BEFORE DROPPING OFF TO 5 TO 10 KT BY MONDAY NIGHT.
KREIN
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS LINCOLN IL
1151 PM CST FRI MAR 8 2013
.DISCUSSION...
ISSUED 855 PM CST FRI MAR 8 2013
UPDATED THE FORECAST TO INCREASE CLOUD COVER TONIGHT AND ELEVATE
LOW TEMPERATURES UP A DEGREE OR TWO. LOWS RANGE FROM NEAR 30F OVER
EAST CENTRAL IL TO THE UPPER 30S FROM SPRINGFIELD SW. CONTINUE A
CHANCE OF LIGHT RAIN SHOWERS OVERNIGHT OVER THE IL RIVER VALLEY...
WITH BEST CHANCES NW OF THE IL RIVER LATE TONIGHT.
1031 MB HIGH PRESSURE OVER SE LOWER MI INTO OHIO AND EASTERN KY
THAT PROVIDE A NICE DAY TO CENTRAL/SE IL WITH AMPLE SUNSHINE AND
MILDER 40S WILL DRIFT INTO THE EASTERN GREAT LAKES SAT MORNING.
1001 MB LOW PRESSURE OVER SE CO WILL DEEPEN TO 997 MB NEAR THE SE
CO/SW KS BORDER BY MIDDAY SAT WITH A FRONTAL BOUNDARY EXTENDING NE
INTO FAR NW IA AND INTO MN. A WARM FRONT OVER SW MO INTO SOUTH
CENTRAL NE WILL LIFT NE TOWARD SW IL SAT MORNING. STRONG WAA
ADVECTION AND ISENTROPIC LIFT TO DEVELOP AND SPREAD LIGHT RAIN
SHOWERS FROM CENTRAL AND WESTERN MO/IA INTO THE IL RIVER VALLEY
OVERNIGHT INTO SAT MORNING MAINLY AFTER 09Z/3 AM. HRRR APPEARS TO
WET WITH SHOWERS OVER MOST OF CWA OVERNIGHT. SINCE SOUNDINGS ARE
QUITE DRY ESPECIALLY FROM I-55 EAST...THIS SHOULD KEEP AREAS FROM
I-55 EAST DRY TONIGHT. TEMPS CURRENTLY IN THE MID TO UPPER 30S
FROM MACOMB TO LINCOLN TO MATTOON NE AND 40-45F SW WILL SLIP ONLY
A FEW MORE DEGREES DUE TO INCREASING/THICKENING MID/HIGH CLOUDS AND
ESE WINDS OF 5-15 MPH.
07
&&
.AVIATION...
ISSUED 1150 PM CST FRI MAR 8 2013
VFR CONDITIONS GENERALLY EXPECTED TO PREVAIL ACROSS THE CENTRAL IL
TERMINAL AIRPORTS NEXT 24 HOURS THROUGH 06Z/MIDNIGHT SAT NIGHT.
EXPECT BROKEN TO OVERCAST MID LEVEL CLOUDS TO LOWER FROM 10-15K FT
TO 5-10K FT DURING OVERNIGHT INTO SAT MORNING...THEN LIFT BACK UP
TO AROUND 10K FT SAT AFTERNOON INTO MID EVENING SAT. STRONG WAA AND
ISENTROPIC LIFT TO GENERATE A LIGHT BAND OF SHOWERS OVER CENTRAL
IL OVERNIGHT (SPI RECENTLY REPORTED SPRINKLES) WITH VSBYS STAYING
ABOVE 5 MILES. MORE WIDESPREAD SHOWERS COULD BRUSH THE IL RIVER
VALLEY NEAR PIA SAT MORNING AND POSSIBLY LINGER INTO EARLY SAT
AFTERNOON WITH CEILINGS DOWN TO 3-5K FT AND VSBYS DOWN TO 5 MILES.
SE WINDS 10-15 KTS OVERNIGHT TO INCREASE TO AROUND 15 KTS WITH
GUSTS 20-25 KTS BY 15Z/SAT AND VEER SSE SAT EVENING. 1000 MB LOW
PRESSURE OVER SE CO TO MOVE INTO SE KS BY 06Z/MID SAT NIGHT WITH A
FRONTAL BOUNDARY INTO EASTERN IA. THIS WILL BRING A WIDESPREAD
BAND OF MODERATE SHOWERS EAST TOWARD THE IL RIVER VALLEY AFTER
04Z/10 PM SAT AND LIKELY TO AFFECT PIA AND NEAR I-55 AT BMI AND SPI
NEAR OR JUST AFTER 06Z/MID SAT NIGHT.
07
&&
.PREV DISCUSSION...
ISSUED 300 PM CST FRI MAR 8 2013
OUR SURFACE PATTERN IS CURRENTLY DOMINATED BY HIGH PRESSURE
EXTENDING FROM THE WESTERN GREAT LAKES ON SOUTH TO
MISSISSIPPI...WHILE LOW PRESSURE IN THE SOUTHWEST STATES BEGINS TO
MOVE ONSHORE AND DEVELOP UNDER A STRENGTHENING JET STREAM. THAT
SYSTEM WILL BECOME OUR MAIN WEATHER ISSUE FOR THE NEXT 3 DAYS OR
SO. OUTSIDE OF A BRIEF COOL DOWN ON MONDAY INTO
TUESDAY...TEMPERATURES OVER THE NEXT WEEK WILL BE AT OR ABOVE
NORMAL.
SHORT TERM...TONIGHT THROUGH SUNDAY NIGHT.
MID AND HIGH CLOUDS WILL ADVANCE INTO ILLINOIS TONIGHT AS MID
LEVEL WARM ADVECTION AND MOISTURE FLOWS BEGIN TO SATURATE THE
LOWER TROPOSPHERE. FORECAST SOUNDINGS ARE INDICATING MOST AREAS
WILL REMAIN DRY OVERNIGHT...ALTHOUGH WE CANT RULE OUT SOME LIGHT
RAIN SHOWERS FOR OUR FAR WESTERN COUNTIES FROM SCHUYLER TO KNOX
LATE TONIGHT. THE GFS IS THE ONLY MODEL TO BRING MUCH IN THE WAY
OF MEASURABLE RAIN BEFORE 12Z TO OUR WESTERN COUNTIES...SO WE
OPTED TO TREND VERY LOW ON THE POPS TONIGHT.
ON SATURDAY...THE PRIMARY FORCING FOR PRECIP WILL REMAIN FOCUSED
NORTHWEST OF I-55...WHILE AREAS SOUTHEAST OF I-55 REMAIN MAINLY
DRY. WE KEPT LIKELY POPS TOWARD FULTON AND KNOX COUNTIES...WITH
CHANCE POPS DOWN TO I-55. SOUTHEAST WINDS WILL BEGIN TO RESPOND TO
THE PRESSURE FALLS BY SATURDAY AFTERNOON...WITH WINDS IN THE 20-30
MPH RANGE AT TIMES. THE GUSTY WINDS WILL CONTINUE TO AID THE
MOISTURE TRANSPORT IN THE BOUNDARY LAYER SATURDAY NIGHT. WE
KEPT CATEGORICAL POPS SAT EVENING AND EXPANDED THEM NEARLY
EVERYWHERE AFTER MIDNIGHT.
THE BULK OF OUR RAINFALL AMOUNTS LOOK TO BE FOCUSED FROM MIDNIGHT
SATURDAY NIGHT THROUGH NOON ON SUNDAY...WITH ELEVATED THUNDERSTORMS
EVEN POSSIBLE AT TIMES LATE SAT NIGHT AND SUNDAY MORNING AS THE
COLD FRONT MOVES ACROSS THE AREA. WE KEPT THE MENTION OF THUNDER
MAINLY CONFINED WEST OF SPI SAT NIGHT AND SOUTH OF LINCOLN ON
SUNDAY MORNING. STRONG SOUTH WINDS WILL ACCOMPANY THE RAIN SHOWERS
AND STORMS AS THEY PUSH ACROSS THE AREA. WIND GUSTS OVER 30MPH
WILL BE POSSIBLE.
BY SUNDAY AFTERNOON THE BEST INSTABILITY WILL HAVE SHIFTED EAST
INTO INDIANA AS COLDER AIR BEGINS TO INVADE CENTRAL IL ON
NORTHWEST WINDS. DOWNWARD ISENTROPIC MOTIONS AND A DRY PUSH ALOFT
WILL HELP TO DIMINISH PRECIP SUNDAY NIGHT FROM NW TO SE. WE KEPT
CHANCE POPS IN THE SOUTHEAST HALF...WITH THE POTENTIAL FOR SOME
LIGHT SNOW NW OF I-70 AFTER MIDNIGHT. LITTLE IN THE WAY OF SNOW
ACCUMULATION IS EXPECTED...AS THE WET AND WARM GROUND MELTS MOST
OF ANY SNOWFALL.
LONG TERM...MONDAY THROUGH FRIDAY.
LINGERING LIGHT SNOW OR RAIN ON MONDAY MORNING SHOULD TAPER TO
SPRINKLES BY AFTERNOON. WE KEPT SLIGHT CHANCE POPS IN THE
SOUTHEAST...BUT MOST PRECIP SHOULD BE TRACE AMOUNTS BY THAT TIME.
THE COLDEST TEMPS OF THE NEXT WEEK SHOULD BE ON MONDAY AND MONDAY
NIGHT...WITH HIGHS ONLY AROUND 40 AND LOWS IN THE MID 20S. TEMPS
WILL BEGIN A WARMING TREND ON TUESDAY WHICH WILL CONTINUE THROUGH
THURSDAY WHEN HIGHS RETURN TO THE 50S. A COOL DOWN IS PROJECTED
FOR THURSDAY NIGHT INTO FRIDAY AS THE NEXT COLD FRONT MOVES
ACROSS THE AREA EITHER EARLY THURSDAY MORNING /GFS/ OR LATE
THURSDAY /ECMWF/. STILL THE COLDER AIR WILL NOT PLUNGE VERY FAR
SOUTH INTO OUR COUNTIES...SO THE COOL DOWN WILL BE TEMPORARY.
PRECIP CHANCES HAVE BEEN KEPT IN THE SLIGHT CHANCE CATEGORY...AND
ONLY ON FRIDAY FOR NOW.
SHIMON
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS WICHITA KS
1150 PM CST FRI MAR 8 2013
.AVIATION...06Z TAFS KRSL/KSLN/KHUT/KICT/KCNU
EXPECT DETERIORATING AVIATION CONDITIONS OVERNIGHT TO IFR CONDITIONS
BETWEEN 06-12Z/SAT AT MOST LOCATIONS AS WIDESPREAD SHOWERS MOVE INTO
THE AREA. THIS INITIAL ROUND OF SHOWERS AND EMBEDDED THUNDERSTORMS
WILL MOVE INTO AREAS WEST OF INTERSTATE 135 IN THE NEXT COUPLE OF
HOURS. WILL SEE ANOTHER ROUND OF SHOWERS AND EMBEDDED THUNDER MOVE
IN AROUND 12Z/SAT...WITH WIDESPREAD SHOWERS REMAINING ACROSS THE
AREA THROUGH 18Z/SAT.
THE DRY LINE ASSOCIATED WITH THIS STORM SYSTEM WILL PUSH INTO THE
KRSL/KHUT AND KICT TAF SITES FOR SAT AFTERNOON...WHICH WILL SCOUR
OUT THE IFR CEILINGS...AS A MID LEVEL DRY SLOT MOVES ACROSS THE
AREA. THIS DRYING OUT OF THE LOW LAYERS...AND SOME POSSIBLE HEATING
DUE SOME PEAKS OF SUNSHINE MAY ALSO LEAD TO A RENEWED CHANCE OF
THUNDERSTORMS FOR THE KHUT/KICT AND KSLN TAFS...SO WILL INCLUDE A
VCTS FOR THIS CHANCE FOR NOW.
MAIN LOW PRESSURE AREA ASSOCIATED WITH THIS STORM SYSTEM WILL MOVE
ACROSS THE FORECAST AREA FOR SAT EVENING. THIS WILL KEEP THE WINDS
OUT OF THE SOUTH FOR THE EVENING HOURS...BUT A STRONG COLD FRONT
WILL BEGIN PUSH SOUTH INTO CEN KS BY AROUND 06Z/SUN...WHICH IS
BEYOND THIS TAF SET.
KETCHAM
&&
.PREV DISCUSSION... /ISSUED 905 PM CST FRI MAR 8 2013/
UPDATE...
THE SCATTERED SHOWER CHANCES HAVE BEEN SLOW TO GET GOING ACROSS MOST
OF THE FORECAST AREA AT THIS TIME. WITH MAINLY SOME WIDELY SCATTERED
SPRITZES/SPRINKLES OR DRIZZLE. LOW LEVEL ISENTROPIC LIFT CONTINUES
TO LEAD TO LOTS OF LOW-MID CLOUDS WITH THIS LOW LEVEL SATURATION
LEADING TO GRADUALLY LOWER CEILINGS. THINK THE WIDESPREAD SHOWER
CHANCES WILL WAIT UNTIL THE INITIAL IMPULSE /THAT IS LEADING TO THE
LINE OF CONVECTION IN THE TX PANHANDLE/ BEGINS TO LIFT NORTHEAST
INTO SRN KS AFTER MIDNIGHT.. THINK AS THIS IMPULSE LIFTS
NORTH...SHOWERS WILL BECOME MORE WIDESPREAD FOR AREAS WEST OF
INTERSTATE 135...WHERE BETTER MOISTURE TRANSPORT IS ALREADY IN
PLACE. SHORT TERM RUC ALSO SHOWS SOME ELEVATED MUCAPE AROUND 400-600
J/KG MOVING INTO THIS AREA AS WELL...SO THINK SOME RUMBLES OF
EMBEDDED THUNDER MAY ALSO MOVE IN AS WELL. CURRENT GRIDS/ZONES LOOK
RIGHT ON TRACK...WITH POPS A LITTLE HIGH EARLY ON...BUT THEY LOOK
FINE FOR AFTER MIDNIGHT.
KETCHAM
PREV DISCUSSION... /ISSUED 558 PM CST FRI MAR 8 2013/
AVIATION...00Z TAFS KRSL/KSLN/KHUT/KICT/KCNU
MVFR CEILINGS WILL GRADUALLY MOVE INTO MOST OF THE TAF SITES THIS
EVENING. EXPECT DETERIORATING AVIATION CONDITIONS OVERNIGHT TO IFR
CONDITIONS BETWEEN 06-12Z/SAT AT MOST LOCATIONS AS WIDESPREAD
SHOWERS DEVELOP. COULD ALSO SEE SOME EMBEDDED THUNDER AS WELL FOR
MOST TAF LOCATIONS BETWEEN 12-18Z/SAT. THE DRY LINE ASSOCIATED WITH
THIS STORM SYSTEM WILL PUSH INTO THE KRSL/KHUT AND KICT TAF SITES
LATE IN THE TAF PERIOD...WHICH WILL SCOUR OUT THE IFR CEILINGS. THIS
DRYING OUT OF THE LOW LAYERS...AND SOME POSSIBLE HEATING DUE SOME
PEAKS OF SUNSHINE MAY ALSO LEAD TO A RENEWED CHANCE OF
THUNDERSTORMS...SO WILL INCLUDE A VCTS FOR THIS CHANCE FOR THE
KHUT/KRSL/KSLN AND KICT TAF SITES.
KETCHAM
PREV DISCUSSION... /ISSUED 328 PM CST FRI MAR 8 2013/
DISCUSSION...
FORECAST HIGHLIGHTS FOCUS AROUND PRECIPITATION CHANCES
TONIGHT-SUNDAY...INCLUDING THE POTENTIAL FOR A FEW STRONG SEVERE
STORMS SATURDAY AFTERNOON-EVENING...AND SNOW SATURDAY NIGHT-SUNDAY
MORNING.
IMPRESSIVE LOOKING UPPER LOW WITH QUITE A BIT OF LIGHTNING IS
CURRENTLY SPINNING OVER THE DESERT SOUTHWEST. AS THIS STORM SYSTEM
APPROACHES THE REGION TONIGHT...ANTICIPATING WIDESPREAD SHOWERS
WITH EMBEDDED THUNDERSTORMS TO BE ON THE INCREASE...ESPECIALLY
AFTER MIDNIGHT GENERALLY OVER CENTRAL AND SOUTH-CENTRAL KS. GIVEN
WEAK INSTABILITY...CANNOT RULE OUT SMALL HAIL WITH THE STRONGEST
STORMS. THIS WIDESPREAD SHIELD OF SHOWERS/THUNDERSTORMS WILL
GRADUALLY SHIFT EAST ACROSS THE AREA DURING THE DAY SATURDAY...IN
ZONE OF STRONG LOW TO MID-LEVEL WARM/MOIST ADVECTION AHEAD OF
APPROACHING UPPER WAVE.
BY TOMORROW MID-AFTERNOON...BRUNT OF MAIN PRECIPITATION SHIELD
SHOULD BE OVER THE EASTERN 1/3 OF KS...WITH SURFACE DRYLINE HANGING
BACK WESTWARD OVER CENTRAL/SOUTH-CENTRAL KS...AND COOLING/DRYING
ALOFT OVERSPREADING THE WARM SECTOR AHEAD OF APPROACHING SHORTWAVE.
IF BREAKS IN OVERCAST CAN DEVELOP ALLOWING SOME HEATING IN WAKE OF
MAIN PRECIPITATION SHIELD...THINKING THERE COULD BE A WINDOW OF
OPPORTUNITY FROM MID-AFTERNOON THROUGH EARLY EVENING FOR SCATTERED
SHALLOW/LOW-TOPPED SURFACE BASED CONVECTION GENERALLY ALONG/WEST OF
I-135 CORRIDOR. IF ENOUGH INSTABILITY CAN MATERIALIZE FOR
STORMS...LOW-TOPPED SUPERCELLS WILL BE POSSIBLE GIVEN STRONGLY
SHEARED ENVIRONMENT...WITH THE POTENTIAL FOR SOME LARGE HAIL.
ADDITIONALLY...NAM BUFR SOUNDINGS INDICATE DECENT LOW-LEVEL CAPE
OWING TO MID-UPPER 50F DEWPOINTS AND STEEPENING LAPSE RATES...WHICH
WOULD SUPPORT THE POTENTIAL FOR AN ISOLATED TORNADO OR TWO. WILL NOT
COMPLETELY BITE ONTO THE OMINOUS NAM SOLUTION JUST YET GIVEN
AFTERNOON HEATING/INSTABILITY QUESTIONS...BUT DEFINITELY SOMETHING
FOR THE NIGHT SHIFT TO EVALUATE FURTHER.
BY SATURDAY NIGHT-EARLY SUNDAY...AS UPPER LOW SHIFTS EAST AND MUCH
COLDER AIR FILTERS SOUTH...THINKING CENTRAL KS COULD SEE A PERIOD OF
LIGHT SNOW. CURRENT INDICATIONS SUGGEST HEAVIEST SNOW WILL REMAIN
OFF TO THE NORTH/NORTHWEST...BUT PORTIONS OF CENTRAL KS COULD
RECEIVE UP TO 1 INCH OR SO AFTER MIDNIGHT SATURDAY NIGHT THROUGH
SUNDAY MORNING. SUNDAY WILL LIKELY BE THE COLDEST DAY OF THE NEXT
7-10 DAYS...WITH HIGHS IN THE 30S-40S AND A STOUT NORTH WIND.
GIVEN CURRENT MODEL CONSENSUS...CONFIDENCE IS MODERATE TO HIGH THAT
DRY AND WARMING CONDITIONS WILL PREVAIL MONDAY THROUGH NEXT
WEEKEND...AS MID/UPPER FLOW FLATTENS OUT SOME AND ATMOSPHERIC
HEIGHTS/THICKNESS INCREASES. HIGHS IN THE 50S-60S APPEAR LIKELY.
ADK
&&
.PRELIMINARY POINT TEMPS/POPS...
WICHITA-KICT 52 62 35 40 / 70 80 40 30
HUTCHINSON 52 63 33 39 / 70 70 40 40
NEWTON 51 61 33 38 / 70 80 50 40
ELDORADO 51 60 35 41 / 70 80 50 30
WINFIELD-KWLD 52 61 37 42 / 70 80 50 20
RUSSELL 52 65 29 38 / 50 50 60 60
GREAT BEND 53 67 30 39 / 50 50 60 60
SALINA 52 63 32 38 / 60 70 50 50
MCPHERSON 52 63 32 38 / 70 70 50 50
COFFEYVILLE 53 61 44 46 / 50 90 70 30
CHANUTE 51 59 42 44 / 50 90 70 40
IOLA 50 59 41 44 / 50 90 70 40
PARSONS-KPPF 52 60 42 45 / 50 90 70 30
&&
.ICT WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
1238 AM EST SAT MAR 9 2013
.SHORT TERM...(THIS EVENING THROUGH SATURDAY)
ISSUED AT 431 PM EST FRI MAR 8 2013
WATER VAPOR IMAGERY AND RUC ANALYSIS SHOW SPLIT FLOW DOMINATING
NAMERICA. IN THE SRN STREAM...POTENT LOOKING SHORTWAVE HAS MOVED
ONSHORE OVER SRN CA WHILE ANOTHER WAVE IS DROPPING S OVER WRN OR/NRN
CA. BOTH OF THESE WAVES WILL PLAY A ROLE IN THE WX ACROSS THE GREAT
LAKES IN THE COMING DAYS. DOWNSTREAM OF THE WRN TROF...RIDGING IS
OVER THE CNTRL CONUS. TO THE N...ONE SHORTWAVE IS TRACKING THRU NRN
ONTARIO. ANOTHER WAVE IS DROPPING SE INTO ALBERTA ON THE PERIPHERY
OF POLAR VORTEX CENTERED JUST N OF HUDSON BAY. THIS WAVE WILL ALSO
PLAY A ROLE IN THE WX OVER THE GREAT LAKES IN THE COMING DAYS.
CLOSER TO HOME...LOW CLOUDS HAVE LINGERED OVER THE ERN FCST AREA IN
SRLY FLOW OFF LAKE MI. HOWEVER...RECENTLY...ONLY A SMALL AREA OF
STRATOCU REMAINS...STREAMING ONSHORE IN SRN SCHOOLCRAFT COUNTY.
ELSEWHERE...EARLY MARCH SUNSHINE IS DOING ITS JOB ON THE LOWER
ALBEDO FORESTED LAND OF THE U.P. TEMPS HAVE PUSHED INTO THE 40S AT A
NUMBER OF OBS SITES OVER WRN UPPER MI.
IN THE SHORT TERM...QUIET WX TONIGHT WILL GIVE WAY TO INCREASING
PCPN CHANCES SAT UNDER STRENGTHENING WAA REGIME AHEAD OF NRN STREAM
WAVE THAT WILL BE MOVING INTO SRN MANITOBA/ND AND SRN STREAM WAVE
EMERGING OVER THE SRN HIGH PLAINS. TONIGHT...SRLY FLOW WILL BE ON
THE INCREASE AHEAD OF THE AFOREMENTIONED SHORTWAVES. THERE IS THE
USUAL CONCERN UNDER SRLY FLOW THAT LOW CLOUDS MAY DEVELOP. IN THIS
CASE...HOWEVER...THE NAM AND GFS SHOW DRY AIR ADVECTION TONIGHT AT
THE LOW-LEVELS AS TRAJECTORIES STILL HAVE SUFFICIENT COMPONENT
EMANATING FROM RETREATING HIGH PRES. SO...LOW CLOUDS MAY NOT REALLY
BE AN ISSUE TONIGHT. IF ANY VERY LOW/SHALLOW STRATUS DOES DEVELOP...
IT SHOULD ONLY BE IN THE AREAS WITH BEST UPSLOPING OVER CNTRL UPPER
MI. OTHERWISE...EXPECT GENERALLY PARTLY CLOUDY SKIES IN THE
EVENING...AND THEN AN INCREASE IN HIGH CLOUDS OVERNIGHT. TYPICAL FOR
THIS TYPE OF INITIALLY RATHER WEAK SRLY FLOW...EXPECT LOWEST MINS
NEAR THE BAY OF GREEN BAY AS ICE COVER ENHANCES COOLING AND
STRENGTHENS NOCTURNAL INVERSION IN THAT AREA. LOWS SHOULD BE AROUND
20F THERE.
ON SAT...UNDER STRONG WAA AND ISENTROPIC ASCENT (295K SFC)...EXPECT
PCPN TO DEVELOP FROM W TO E AS LOW-LEVEL DRY AIR IS EVENTUALLY
OVERCOME. TRAJECTORIES SUGGEST THERE WILL BE SOME MAINTENANCE
OF THE LOW-LEVEL DRY AIR OVER THE E EVEN AS FORCING AND RESULTING
PCPN ALOFT OVERSPREAD THAT AREA. SO...POPS WILL SHOW A GRADIENT FROM
CATEGORICAL W TO JUST CHC E LATE. IT`S QUITE POSSIBLE THE E MAY
NOT SEE ANY PCPN SAT. AS FOR PTYPE...IT`S A CHALLENGE AS IT ALMOST
ALWAYS IS WHEN IT`S NOT COLD ENOUGH FOR JUST SNOW OR WARM ENOUGH FOR
JUST RAIN. THERE WILL BE THE USUAL BATTLE BETWEEN STRONG WAA AND THE
COOLING IT GENERATES THRU ASCENT AS WELL AS EVAPORATIVE COOLING
EARLY ON. BELIEVE THE EVAPORATIVE COOLING EARLY ON WILL LEAD TO
PREDOMINANTLY SNOW AS THE PTYPE INITIALLY. THEREAFTER...FCST
SOUNDINGS SHOW PROFILE GENERALLY HOVERING AROUND 0C IN THE LOWER
LEVELS...FLUCTUATING BASED ON ASCENT/PCPN INTENSITY. MEANWHILE...THE
NEAR SFC LAYER MAY RESPOND A LITTLE TO DAYTIME HEATING...PUSHING THE
ODDS TOWARD RAIN. AT THIS POINT...WILL INCLUDE SNOW AS THE GENERAL
PREVAILING PTYPE IN MOST AREAS WITH A MENTION OF RAIN. INCLUDED FZRA
AS WELL WHERE TEMPS ARE AROUND FREEZING. IF THERE IS FZRA...IT
SHOULD BE CONFINED TO THE MORNING/EARLY AFTN BEFORE SURFACES RESPOND
TO WEAK DAYTIME HEATING. WITH TEMPS PUSHING INTO THE MID 30S...
WET/SLUSHY SNOW ACCUMULATIONS WILL BE MINOR...MAYBE AROUND AN INCH.
.LONG TERM...(SATURDAY NIGHT THROUGH FRIDAY)
ISSUED AT 431 PM EST FRI MAR 8 2013
SATURDAY NIGHT...
THE MODELS HAVE COME INTO BETTER AGREEMENT WITH THE EVOLUTION OF THE
SYOPTIC PATTERN WITH A PROGRESSIVE PATTERN AND LITTLE PHASING
BETWEEN THE NRN STREAM MID LEVEL TROUGH MOVING THROUGH NRN ONTARIO
AND THE NRN GREATLAKES AND THE SRN STREAM SHORTWAVE MOVING EAST FROM
THE PLAINS.
ABUNDANT MOISTURE INFLOW WITH MODERATE TO STRONG 285K-300K
ISENTROPIC LIFT AND A PERIOD OF 700-600 MB FGEN SHOULD SUPPORT A
BAND OF PCPN THROUGH THE CWA...ESPECIALLY BTWN 00Z-06Z WITH QPF
AMOUNTS TO AROUND 0.25 INCH. CONFIDENCE IS ALSO HIGHER THAT A
SIGNIFCANT (1C TO 3C) WARM LAYER WILL SPREAD THROUGH MOST OF THE CWA
GIVEN STRONG WAA WITH SW 40-45 KT 850 MB WINDS BY 00Z/SUN. GENERALLY
UTILIZED NAM/GEM LOW LEVEL THERMAL PROFILE TO DELINEATE PCPN TYPE
PATTERN. WITH ENOUGH WARMTH LINGERING FROM DAYTIME HEATING...ANY SFC
COLD LAYER WILL BE LESS PRONOUNCED LIMITING POTENTIAL FOR FZRA.
SO...MAINLY RA/SN MIX EXPECTED WITH THE GREATEST SNOW CHANCES OVER
THE WEST HALF. WITH LOW SLR AOB 10/1...ANY WET SNOWFALL AMOUNTS
SHOULD ONLY AMOUNT TO AN INCH OR TWO AT MOST.
SUNDAY...THERE WERE GREATER MODEL DIFFERENCES AS THE GFS ALLOWS
ANOTHER DEFORMATION BAND OF PCPN TO LIFT INTO UPPER ASSOCIATED WITH
THE SRN STREAM SHRTWV. SINCE THE GLOBAL GEM/ECMWF CONTINUE TO SHOW A
MORE PROGRESSIVE SOLUTION...THE FCST CONTINUES WITH THE IDEA OF
TAPERING OFF POPS/QPF FROM WEST TO EAST WITH MAINLY JUST CHANCE POPS
BY AFTERNOON. SOME LAKE ENHANCED SNOW MAY DEVELOP BUT WITH THE
SYNOPTIC SCALE UPWARD MOTION AND DEEPER MOISTURE DEPARTING...ANY
AMOUNTS SHOULD BE LIGHT.
SUN NIGHT INTO MON...850 MB TEMPS DROPPING INTO THE -12C TO -14C
ALONG WITH CONTINUED CYCLONIC NRLY FLOW COULD STILL SUPPORT SOME
LES. HOWEVER...WITH STRONG 850-700 MB DRYING...ANY AMOUNTS
ARE EXPECTED TO BE LIGHT
TUE-FRI...MDLS WERE CONSISTENT WITH A WEAK CLIPPER SHORTWAVE AND SFC
TROUGH MOVING THROUGH THE UPPER GREAT LAKES MON NIGHT INTO TUE. THE FAVORED
ECMWF REMAINED MORE AMPLIFIED WITH THE ERN GREAT LAKES TROUGH BY WED
WITH COLDER AIR AVAILABLE FOR SOME NW FLOW LES COMPARED TO THE THE
GFS. CONFIDENCE IN DETAILS DROPS OFF BY THU-FRI WITH REGARD TO THE
POSITION/STRENGTH OF THE NEXT SHORTWAVE THAT COULD BRING SNOW CHANCES
INTO THE REGION. TEMPS SHOULD REMAIN AT OR BELOW SEASONAL AVERAGES.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SATURDAY NIGHT)
ISSUED AT 1237 AM EST SAT MAR 9 2013
EXPECT VFR CONDITIONS TO PREVAIL THRU SUNRISE GIVEN DRYNESS OF
UPSTREAM AIRMASS TO THE S AND A STEADY S WIND ON THE WRN FLANK OF
RETREATING HI PRES OVER SE LWR MI THAT IS LIMITING THE POTENTIAL FOR
FOG FORMATION. AN APRCHG LO PRES TROF WL BRING AN INCRSG THREAT W-E
OF SOME SN OR MIXED RA/SN DURING THE LATE MRNG/AFTN ON SAT.
LINGERING LLVL DRYNESS WL SLOW DOWN THE ONSET OF LOWER CIGS/
VSBY...BUT THESE CONDITIONS SHOULD DVLP WITH PERSISTENT PCPN/
MOISTENING. THE BEST SHOT AT IFR OR EVEN LIFR WX WL BE AT CMX...
FARTHER FM DEPARTING LLVL DRY AIR AND WHERE NEAR SFC SE FLOW WL
UPSLOPE.
&&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 431 PM EST FRI MAR 8 2013
SOUTHERLY FLOW WILL DOMINATE TONIGHT THRU SAT EVENING AHEAD OF AN
APPROACHING LOW PRES TROF. TYPICAL FOR SOUTHERLY FLOW...STRONGEST
WINDS WILL BE OVER ERN LAKE SUPERIOR...REACHING UPWARDS OF 30KT SAT
AFTN/EVENING. TROF WILL THEN PASS ACROSS LAKE SUPERIOR LATE SAT
NIGHT/SUN...BRINGING A SHIFT TO 20-30KT NW WINDS. WINDS WILL THEN
SLOWLY SUBSIDE LATE SUN NIGHT/MON...FALLING TO UNDER 15KT FOR MON
NIGHT/TUE. MAY SEE A SLIGHT INCREASE IN WINDS WED.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...ROLFSON
LONG TERM...JLB
AVIATION...KC
MARINE...JLB
AREA FORECAST DISCUSSION
NWS NORTH PLATTE NE
348 AM CST SAT MAR 9 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 345 AM CST SAT MAR 9 2013
TWO ROUNDS OF THOUGHT WITH THE STORM. ONE IS FOR A STRONG FGEN
FORCED BAND OF SNOW DEVELOPING ACROSS NORTHWEST NEBRASKA TODAY
WHICH MOST SOLNS AGREE ON TO VARYING DEGREES. THE SECOND IS FOR
ANOTHER STRONG BAND OF SNOW TO DEVELOP ACROSS SOUTH CENTRAL
NEBRASKA TONIGHT AS THE FIRST BAND DECAYS. THE GEM REGIONAL AND
GFS ARE VERY FAR NORTHWEST WITH THIS BAND SIGNALING A WINTER
STORM FOR NCNTL NEB WHILE THE NAM AND ECM ARE SAFELY EAST OF THE
FCST AREA. A BLEND OF NAM...GEM AND ECM WERE USED FOR THE LATEST
FCST WHICH PROVIDES A WINTER STORM ACROSS THE NORTHWEST AND A
WINTER WEATHER ADVISORY ELSEWHERE.
HOWEVER THE NAM AND RAP SHOW A VERY STRONG BARRIER JET DEVELOPING
THIS EVENING STRETCHING NORTH-SOUTH ALONG AND WEST OF HIGHWAY 83
WHICH COULD EASILY SUPPORT A WINTER STORM IF THE FRONTOGENESIS
WAS APPROPRIATELY JUXTAPOSED. THIS IS NOT THE CASE AS THE NAM
SHOWS THE FGEN AND HEAVY QPF MOSTLY EAST OF THE FCST AREA. THE
RAP MEANWHILE NOSES THE PV1.5 ANOMALY INTO SRN NEB AT 02Z AND
DEVELOPS SOME HEAVY SNOW ACROSS SWRN NEB. THIS IS A CONCERN WHICH
WILL BE CLOSELY MONITORED.
THE STRONG BARRIER JET WILL EASILY SUPPORT 30 MPH WINDS WITH
GUSTS TO 45 MPH. IN FACT THE NAM AND RAP SHOW GUSTS TO 60 MPH AT
00Z-03Z...THE HEIGHT OF THE STORM ACROSS SWRN AND NCNTL NEB.
SO EVERYONE OUTSIDE OF THE WINTER STORM WARNING HAS BEEN PLACED
IN A WINTER WEATHER ADVISORY FOR 3 TO 5 INCHES OF SNOW AND 30 TO
45 MPH WINDS.
.LONG TERM...(SUNDAY THROUGH FRIDAY)
ISSUED AT 345 AM CST SAT MAR 9 2013
MAJOR SPRING/WINTER STORM WILL BE EXITING SUNDAY MORNING WITH
SOME LINGERING LIGHT SNOW ACROSS THE FAR EASTERN COUNTIES. WINDS
WILL CONTINUE TO BE GUSTY...AND WILL HIGHLIGHT PATCHY BLOWING
SNOW WHERE FALLING SNOW IS EXPECTED. PENDING TOTAL SNOW AND HOW
FLUFFY IT IS...MAY NEED TO CONTINUE BLOWING SNOW FURTHER WEST
EARLY SUNDAY. STILL QUESTIONING HOW FAR WEST THE HEAVY BAND OF
SNOW OVER CENTRAL NEB WILL BE.
SUNDAY HIGHS...WITH COLD HIGH PRESSURE BUILDING SOUTH ACROSS THE
NORTHERN PLAINS AND MUCH IF NOT ALL OF THE AREA EXPECTED TO SEE A
SNOW COVER...SHOULD HOLD CLOSE TO 30 DEGREES. ALTHOUGH THE SUN
WILL SPREADING FROM WEST TO EAST...WHICH SHOULD HELP TO START TO
MELT ROADWAYS.
SUNDAY NIGHT WITH AN ELONGATED HIGH ACROSS THE WESTERN
PLAINS...LIGHT WINDS AND MOSTLY CLEAR SKIES ALONG WITH SNOW
PACK...TEMPS SHOULD TANK. WIDESPREAD TEENS...WHICH MAY BE
CONSERVATIVE.
MONDAY INTO MID WEEK RIDGE BUILDS ACROSS THE WEST...WITH A TROUGH
TO PUSH ALONG THE NORTHERN STREAM...ACROSS SOUTHERN CANADA AND
THE GREAT LAKES. WEAK DISTURBANCE TO MOVE ALONG THE NW FLOW
ACROSS THE AREA...HOWEVER MOISTURE LIMITED AND DOUBT ANYTHING
WILL REACH THE GROUND AS TIMING IS A LITTLE SLOWER WITH PASSAGE
MORE OF A DAYTIME AND THE HEAT OF THE DAY SHOULD BE ENOUGH TO
KEEP ANYTHING FROM HITTING THE GROUND. ALSO EARLY IN THE WEEK AS
THE SNOW MELTS WILL NEED TO MONITOR FOR OVERNIGHT/MORNING FOG.
RIDGE EXPANDS AS THE WEEK CONTINUES...WITH STRONG WAA ALOFT WITH
THE WESTERN PART OF THE CWA SEEING DOUBLE DIGIT 850 TEMPS.
QUESTION WILL BE HOW LONG CAN THE SNOW REMAIN AND DAMPEN TEMPS.
GUIDANCE PUSHES HIGHS INTO THE 50S AND 60S FOR WEDNESDAY AND
THURSDAY. AS IS TYPICAL WITH MANY MARCH SNOW STORMS...EXPECT THIS
SNOW NOT TO STAY LONG. ALTHOUGH WEST WINDS ON THE LIGHT
SIDE...LESS THAN 15 MPH...SHOULD BE ENOUGH TO HELP MIX WITH THE
DOWNSLOPE COMPONENT AND HAVE FOLLOWED CLOSER TO GUIDANCE FOR THE
LATER HALF OF THE WEEK.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SATURDAY NIGHT)
ISSUED AT 1153 PM CST FRI MAR 8 2013
ISOLATED THUNDERSTORMS ARE EXPECTED IN EXTREME SOUTHWEST NEBRASKA
NEAR A SURFACE TROUGH AND WARM FRONT. AT THIS TIME...IT APPEARS THAT
CELLS THAT HAVE DEVELOPED ALREADY WILL PASS A LITTLE EAST OF LBF AND
DISSIPATE BEFORE GOING VERY FAR. WIDESPREAD LIGHT RAIN OR DRIZZLE
DEVELOPING NORTH AND WEST OF BBW-LBF IS LIKELY TO SPREAD WESTWARD AS
IT MOVES NORTH...AND IT WILL PROBABLY REACH VTN 08-10Z. BY ABOUT
12Z...A BAND OF PRECIPITATION IS EXPECTED TO DEVELOP NORTH AND WEST
OF AN ONL-OGA LINE. INITIALLY...IT WILL PROBABLY BE RAIN OR A
RAIN/SNOW MIX CHANGING TO SNOW BY ABOUT 14Z AND CONTINUING THROUGH
THE DAY SATURDAY. IN CENTRAL THROUGH SOUTHWEST NEBRASKA...SNOW IS
NOT EXPECTED BEFORE 00Z.
&&
.LBF WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY UNTIL 7 AM CDT /6 AM MDT/ SUNDAY FOR
NEZ006-008-025-026-036-057-058-069.
WINTER WEATHER ADVISORY FROM NOON CST TODAY TO 7 AM CDT SUNDAY
FOR NEZ007-009-010-027>029-037-038-059-070-071.
WINTER STORM WARNING UNTIL 7 AM CDT /6 AM MDT/ SUNDAY FOR NEZ004-
005-022>024-035-056-094.
&&
$$
SHORT TERM...CDC
LONG TERM...MASEK
AVIATION...SPRINGER
AREA FORECAST DISCUSSION...UPDATED
NWS NORTH PLATTE NE
156 AM CST SAT MAR 9 2013
.SYNOPSIS...
UPPER CLOSED LOW MOVING ON SHORE IN SOUTHERN CALIFORNIA AND WILL
CONTINUE ACROSS DESERT SOUTHWEST INTO FOUR CORNERS OVER NIGHT. RIDGE
SHARPENING INTO MISSOURI RIVER BASIN WITH CLOSED LOW OVER NORTHWEST
ATLANTIC.
&&
.UPDATE...
ISSUED AT 156 AM CST SAT MAR 9 2013
GIVEN THE PROJECTED SNOWFALL TOTALS AND STRONG WINDS...IT WOULD BE
PRUDENT TO ISSUE A WINTER WEATHER ADVISORY. SO ADDITIONAL COUNTIES
HAVE BEEN ADDED TO THE WINTER WEATHER ADVISORY WHICH NOW INCLUDES
THE REMAINING PORTION OF NORTH CENTRAL NEBRASKA THAT PREVIOUSLY
WAS EXCLUDED FROM A WINTER WEATHER HIGHLIGHT.
UPDATE ISSUED AT 103 AM CST SAT MAR 9 2013
A NEW FORECAST IS OUT USING A BLEND OF THE NAM AND GEM. USING AN 8
TO 1 RATIO PRODUCED SIGNIFICANT SNOW ACCUMULATIONS ACROSS THE
WARNED AREA AND ELSEWHERE SOUTH AND EAST. ALSO A 50 50 BLEND OF MODEL
WINDS AND MAV MET GUIDANCE EASILY PRODUCED WINDS OVER 30 MPH IN
THE SNOW SO WINTER WEATHER CONDITIONS SHOULD BE IN FULL SWING
TODAY AND TONIGHT.
THE RAP13 MODEL SHOWS AN AREA OF STRONG FRONTOGENESIS DEVELOPING
ACROSS NW NEB THIS MORNING WHICH APPEARS TO BE IN GOOD AGREEMENT
WITH THE NAM AND GEM MODELS. THE RAP THEN SLOWLY PUSHES THE FGEN
AND ASSOCIATED SNOW SOUTH AND EAST DURING THE DAY BUT WEAKENS IT
AT THE SAME TIME.
THUS IT WOULD APPEAR THAT SIGNIFICANT SNOW AND WINTER WEATHER
CONDITIONS WILL DEVELOP ACROSS A GOOD PORTION OF THE FCST AREA
TODAY AND TONIGHT.
UPDATE ISSUED AT 943 PM CST FRI MAR 8 2013
PRECIPITATION IS SLOWER DEVELOPING THAN WE THOUGHT WHEN WE ISSUED
THE FORECAST THIS AFTERNOON. THE UPDATED FORECAST REFLECTS THIS
IDEA.
&&
.SHORT TERM...(THIS EVENING THROUGH SATURDAY)
ATTENTION IN THE SHORT TERM IS FOCUSED ON THE IMPINGING EARLY SPRING
LIKE STORM. A MYRIAD OF WEATHER IS ANTICIPATED...INCLUDING TSTMS AND
FREEZING RAIN. WILL UPGRADE THE CURRENT WINTER STORM WATCH TO A
WARNING...AND INCLUDE EASTERN CHERRY AND HOOKER COUNTY AS THE
HEAVIEST SNOW IS EXPECTED TO BE SLIGHTLY EAST AND SOUTH THAN
ORIGINALLY THOUGHT. WILL ALSO ISSUE A WINTER WEATHER ADVISORY FOR
THE COUNTIES ADJACENT TO OUR CURRENT WARNING...AS MINOR ICE
ACCUMULATIONS AND MODERATE SNOW ACCUMULATIONS ARE EXPECTED.
FOR THE REST OF TODAY AND TONIGHT...OUR STORM OF INTEREST IS
CURRENTLY MOVING ACROSS SOCAL AND NORTHERN BAJA...TOWARD EASTERN
ARIZONA...AND WILL EVENTUALLY PHASE WITH A PROGRESSIVE NORTHERN
STREAM TROUGH. SHORT TERM SOLUTIONS ALL AGREE THAT THE PHASED WAVE
WILL CROSS THE ROCKIES AND SUPPORT CONTINUED CYCLOGENESIS OVER THE
EASTERN HIGH PLAINS OF COLORADO. MEANWHILE STRONG MOISTURE
ADVECTION...CURRENTLY ONGOING...WILL CONTINUE TO TARGET THE SOUTHERN
AND CENTRAL PLAINS...WITH MOISTURE FOCUSED ACROSS WESTERN NEBRASKA
MAINLY IN THE 290-300K SURFACES. THE INCREASING WAA WILL PROVIDE
FOR AN OPPORTUNITY OF -SHRA THIS EVENING. BUFR SOUNDINGS DO SUPPORT
THE CONTINUED MENTION OF THUNDER AS WELL...AS ELEVATED INSTABILITY
INCREASES TO 200-400 J/KG BEFORE MIDNIGHT. WILL TARGET THE HIGHEST
THREATS OF STORMS EAST AND SOUTH OF AN IMPERIAL TO NORTH PLATTE TO
BARTLETT LINE. AS THE EVENING PROGRESSES INTO THE OVERNIGHT...LARGE
SCALE FORCING FOR ASCENT WILL SPREAD EAST WITH THE ENCROACHING
WAVE/UPPER JET...SHOWERS WILL BECOME MORE WIDESPREAD ACROSS THE
CWA...WITH THE POSSIBILITY OF MIXED OR FREEZING PRECIPITATION OVER
OUR NORTHWEST. BUFKIT SOUNDINGS INDICATE THE HIGHEST PROBS OF
FREEZING RAIN NEAR KVTN AROUND DAWN...BUT AMOUNTS SHOULD REMAIN LESS
THAN A TENTH OF AN INCH. SNOW BEGINS TO COLLECT OVERNIGHT OR JUST
BEFORE DAWN ACROSS NORTHWEST NEBRASKA AS MIDLEVEL FRONTOGENETIC BAND
TIGHTENS AND DYNAMIC COOLING ALLOWS FOR ACCUMULATIONS. ALL THE
SHORT TERM MODELS HAVE CONVERGED ON A SOUTHWEST TO NORTHEAST
DEFORMATION BAND...FROM THE SOUTHWESTERN PANHANDLE TO NEAR KVTN.
SNOW ACCUMULATIONS OF 6 INCHES OR MORE WILL BE POSSIBLE IN THE
WARNED AREA. IN ADDITION...NORTHERLY WINDS AT H85 ARE INDICATED TO
BE IN THE 35-40KT RANGE...WE CERTAINLY COULD SEE SOME
BLOWING/DRIFTING OF THE SNOW AS THE WIND GUSTS IN EXCESS OF 25 MPH
TOMORROW AFTERNOON. THE RAIN/SNOW CHANGE OVER LINE WILL BE FOCUSED
ALONG THE ADVANCING COLD FRONT...WHICH IS INDICATED TO CROSS THE
MAJORITY OF THE CWA...SAVE FAR SOUTHEASTERN PORTIONS...BY EARLY
AFTERNOON TOMORROW...WIDESPREAD SNOW SHOULD PREVAIL FOR MOST
LOCATIONS AFTER 21Z. THE INITIAL DEFORMATION ACROSS OUR CWA IS
SHOWN TO WEAKEN AND RE-FOCUS ACROSS SOUTH CENTRAL/CENTRAL NEBRASKA
LATE AFTERNOON TOMORROW...WITH THE HEAVIEST LATE AFTERNOON
ACCUMULATIONS ACROSS EASTERN CUSTER/WHEELER/HOLT COUNTIES.
DEPENDING ON THE PROGRESSION OF THE SYSTEM...AN ADDITIONAL WINTER
WEATHER ADVISORY MAY BE NEEDED FOR THESE AREAS. WILL WAIT AND SEE
HOWEVER...MODEL GUIDANCE WAS TOO FAR WEST WITH THE NORTHERN STREAM
PV ANOMALY THIS MORNING AS COMPARED TO THE ACTUAL OBSERVATIONS...A
MORE EASTWARD PROGRESSIVE NORTHERN STREAM WOULD FAVOR A FURTHER
SOUTHERN AND EASTWARD TREND IN THE SYSTEM...WHICH MAY FOCUS THIS
SECONDARY BAND OUTSIDE OUR CWA.
.LONG TERM...(SATURDAY NIGHT THROUGH FRIDAY)
MODELS HAVE SLIGHT VARIATIONS IN THE LONG TERM. MAIN CONCERN IS
DEFORMATION ZONE MOVING SOUTH AND EAST THROUGH THE DAY ON
SATURDAY INTO SATURDAY NIGHT. THE ECMWF IS STRONGEST WITH THE ZONE
COMING ACROSS AND THEN VARYING DEGREES WITH GFS AND NAM. THE NAM
IS FURTHER EAST. HAVE HELD OFF ON ANY HIGH LIGHTS FOR SATURDAY
NIGHT WITH WINDS DECREASING AND THEN TRENDS TOWARDS MODELS
SHIFTING SYSTEM FURTHER EAST. PRECIPITATION ENDING SUNDAY MORNING
TEMPERATURES IN THE 20S AND 30S FOR DAYTIME HIGHS. KEPT COOLER
TEMPERATURES OVER SNOW COVER THROUGH MONDAY. POSSIBILITY OF FOG
SUNDAY MORNING AND MONDAY NIGHT TUESDAY MORNING WITH MELTING SNOW.
COULD BE SOME JET INDUCED SNOW SHOWERS TUESDAY IN FAST NORTHWEST
FLOW. UPPER JET CURLS NORTH WEDNESDAY AND PACIFIC AIR MOVES INTO
FORECAST AREA. NICE WARMING TREND WITH TEMPERATURES RISING INTO
THE UPPER 40S NORTHEAST TO AROUND 60 SOUTHWEST AND WEST. GENERALLY
DRY AFTER TUESDAY.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SATURDAY NIGHT)
ISSUED AT 1153 PM CST FRI MAR 8 2013
SOLATED THUNDERSTORMS ARE EXPECTED IN EXTREME SOUTHWEST NEBRASKA
NEAR A SURFACE TROUGH AND WARM FRONT. AT THIS TIME...IT APPEARS THAT
CELLS THAT HAVE DEVELOPED ALREADY WILL PASS A LITTLE EAST OF LBF AND
DISSIPATE BEFORE GOING VERY FAR. WIDESPREAD LIGHT RAIN OR DRIZZLE
DEVELOPING NORTH AND WEST OF BBW-LBF IS LIKELY TO SPREAD WESTWARD AS
IT MOVES NORTH...AND IT WILL PROBABLY REACH VTN 08-10Z. BY ABOUT
12Z...A BAND OF PRECIPITATION IS EXPECTED TO DEVELOP NORTH AND WEST
OF AN ONL-OGA LINE. INITIALLY...IT WILL PROBABLY BE RAIN OR A
RAIN/SNOW MIX CHANGING TO SNOW BY ABOUT 14Z AND CONTINUING THROUGH
THE DAY SATURDAY. IN CENTRAL THROUGH SOUTHWEST NEBRASKA...SNOW IS
NOT EXPECTED BEFORE 00Z.
&&
.LBF WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY UNTIL 7 AM CDT /6 AM MDT/ SUNDAY FOR
NEZ006-008-025-026-036-057-058-069.
WINTER WEATHER ADVISORY FROM NOON CST TODAY TO 7 AM CDT SUNDAY
FOR NEZ007-009-010-027>029-037-038-059-070-071.
WINTER STORM WARNING UNTIL 7 AM CDT /6 AM MDT/ SUNDAY FOR NEZ004-
005-022>024-035-056-094.
&&
$$
UPDATE...CDC
SYNOPSIS...POWER
SHORT TERM...JACOBS
LONG TERM...POWER
AVIATION...SPRINGER
AREA FORECAST DISCUSSION...UPDATED
NWS NORTH PLATTE NE
111 AM CST SAT MAR 9 2013
.SYNOPSIS...
UPPER CLOSED LOW MOVING ON SHORE IN SOUTHERN CALIFORNIA AND WILL
CONTINUE ACROSS DESERT SOUTHWEST INTO FOUR CORNERS OVER NIGHT. RIDGE
SHARPENING INTO MISSOURI RIVER BASIN WITH CLOSED LOW OVER NORTHWEST
ATLANTIC.
&&
.UPDATE...
ISSUED AT 103 AM CST SAT MAR 9 2013
A NEW FORECAST IS OUT USING A BLEND OF THE NAM AND GEM. USING AN 8
TO 1 RATIO PRODUCED SIGNIFICANT SNOW ACCUMULATIONS ACROSS THE
WARNED AREA AND ELSEWHERE SOUTH AND EAST. ALSO A 50 50 BLEND OF MODEL
WINDS AND MAV MET GUIDANCE EASILY PRODUCED WINDS OVER 30 MPH IN
THE SNOW SO WINTER WEATHER CONDITIONS SHOULD BE IN FULL SWING
TODAY AND TONIGHT.
THE RAP13 MODEL SHOWS AN AREA OF STRONG FRONTOGENESIS DEVELOPING
ACROSS NW NEB THIS MORNING WHICH APPEARS TO BE IN GOOD AGREEMENT
WITH THE NAM AND GEM MODELS. THE RAP THEN SLOWLY PUSHES THE FGEN
AND ASSOCIATED SNOW SOUTH AND EAST DURING THE DAY BUT WEAKENS IT
AT THE SAME TIME.
THUS IT WOULD APPEAR THAT SIGNIFICANT SNOW AND WINTER WEATHER
CONDITIONS WILL DEVELOP ACROSS A GOOD PORTION OF THE FCST AREA
TODAY AND TONIGHT.
UPDATE ISSUED AT 943 PM CST FRI MAR 8 2013
PRECIPITATION IS SLOWER DEVELOPING THAN WE THOUGHT WHEN WE ISSUED
THE FORECAST THIS AFTERNOON. THE UPDATED FORECAST REFLECTS THIS
IDEA.
&&
.SHORT TERM...(THIS EVENING THROUGH SATURDAY)
ATTENTION IN THE SHORT TERM IS FOCUSED ON THE IMPINGING EARLY SPRING
LIKE STORM. A MYRIAD OF WEATHER IS ANTICIPATED...INCLUDING TSTMS AND
FREEZING RAIN. WILL UPGRADE THE CURRENT WINTER STORM WATCH TO A
WARNING...AND INCLUDE EASTERN CHERRY AND HOOKER COUNTY AS THE
HEAVIEST SNOW IS EXPECTED TO BE SLIGHTLY EAST AND SOUTH THAN
ORIGINALLY THOUGHT. WILL ALSO ISSUE A WINTER WEATHER ADVISORY FOR
THE COUNTIES ADJACENT TO OUR CURRENT WARNING...AS MINOR ICE
ACCUMULATIONS AND MODERATE SNOW ACCUMULATIONS ARE EXPECTED.
FOR THE REST OF TODAY AND TONIGHT...OUR STORM OF INTEREST IS
CURRENTLY MOVING ACROSS SOCAL AND NORTHERN BAJA...TOWARD EASTERN
ARIZONA...AND WILL EVENTUALLY PHASE WITH A PROGRESSIVE NORTHERN
STREAM TROUGH. SHORT TERM SOLUTIONS ALL AGREE THAT THE PHASED WAVE
WILL CROSS THE ROCKIES AND SUPPORT CONTINUED CYCLOGENESIS OVER THE
EASTERN HIGH PLAINS OF COLORADO. MEANWHILE STRONG MOISTURE
ADVECTION...CURRENTLY ONGOING...WILL CONTINUE TO TARGET THE SOUTHERN
AND CENTRAL PLAINS...WITH MOISTURE FOCUSED ACROSS WESTERN NEBRASKA
MAINLY IN THE 290-300K SURFACES. THE INCREASING WAA WILL PROVIDE
FOR AN OPPORTUNITY OF -SHRA THIS EVENING. BUFR SOUNDINGS DO SUPPORT
THE CONTINUED MENTION OF THUNDER AS WELL...AS ELEVATED INSTABILITY
INCREASES TO 200-400 J/KG BEFORE MIDNIGHT. WILL TARGET THE HIGHEST
THREATS OF STORMS EAST AND SOUTH OF AN IMPERIAL TO NORTH PLATTE TO
BARTLETT LINE. AS THE EVENING PROGRESSES INTO THE OVERNIGHT...LARGE
SCALE FORCING FOR ASCENT WILL SPREAD EAST WITH THE ENCROACHING
WAVE/UPPER JET...SHOWERS WILL BECOME MORE WIDESPREAD ACROSS THE
CWA...WITH THE POSSIBILITY OF MIXED OR FREEZING PRECIPITATION OVER
OUR NORTHWEST. BUFKIT SOUNDINGS INDICATE THE HIGHEST PROBS OF
FREEZING RAIN NEAR KVTN AROUND DAWN...BUT AMOUNTS SHOULD REMAIN LESS
THAN A TENTH OF AN INCH. SNOW BEGINS TO COLLECT OVERNIGHT OR JUST
BEFORE DAWN ACROSS NORTHWEST NEBRASKA AS MIDLEVEL FRONTOGENETIC BAND
TIGHTENS AND DYNAMIC COOLING ALLOWS FOR ACCUMULATIONS. ALL THE
SHORT TERM MODELS HAVE CONVERGED ON A SOUTHWEST TO NORTHEAST
DEFORMATION BAND...FROM THE SOUTHWESTERN PANHANDLE TO NEAR KVTN.
SNOW ACCUMULATIONS OF 6 INCHES OR MORE WILL BE POSSIBLE IN THE
WARNED AREA. IN ADDITION...NORTHERLY WINDS AT H85 ARE INDICATED TO
BE IN THE 35-40KT RANGE...WE CERTAINLY COULD SEE SOME
BLOWING/DRIFTING OF THE SNOW AS THE WIND GUSTS IN EXCESS OF 25 MPH
TOMORROW AFTERNOON. THE RAIN/SNOW CHANGE OVER LINE WILL BE FOCUSED
ALONG THE ADVANCING COLD FRONT...WHICH IS INDICATED TO CROSS THE
MAJORITY OF THE CWA...SAVE FAR SOUTHEASTERN PORTIONS...BY EARLY
AFTERNOON TOMORROW...WIDESPREAD SNOW SHOULD PREVAIL FOR MOST
LOCATIONS AFTER 21Z. THE INITIAL DEFORMATION ACROSS OUR CWA IS
SHOWN TO WEAKEN AND RE-FOCUS ACROSS SOUTH CENTRAL/CENTRAL NEBRASKA
LATE AFTERNOON TOMORROW...WITH THE HEAVIEST LATE AFTERNOON
ACCUMULATIONS ACROSS EASTERN CUSTER/WHEELER/HOLT COUNTIES.
DEPENDING ON THE PROGRESSION OF THE SYSTEM...AN ADDITIONAL WINTER
WEATHER ADVISORY MAY BE NEEDED FOR THESE AREAS. WILL WAIT AND SEE
HOWEVER...MODEL GUIDANCE WAS TOO FAR WEST WITH THE NORTHERN STREAM
PV ANOMALY THIS MORNING AS COMPARED TO THE ACTUAL OBSERVATIONS...A
MORE EASTWARD PROGRESSIVE NORTHERN STREAM WOULD FAVOR A FURTHER
SOUTHERN AND EASTWARD TREND IN THE SYSTEM...WHICH MAY FOCUS THIS
SECONDARY BAND OUTSIDE OUR CWA.
.LONG TERM...(SATURDAY NIGHT THROUGH FRIDAY)
MODELS HAVE SLIGHT VARIATIONS IN THE LONG TERM. MAIN CONCERN IS
DEFORMATION ZONE MOVING SOUTH AND EAST THROUGH THE DAY ON
SATURDAY INTO SATURDAY NIGHT. THE ECMWF IS STRONGEST WITH THE ZONE
COMING ACROSS AND THEN VARYING DEGREES WITH GFS AND NAM. THE NAM
IS FURTHER EAST. HAVE HELD OFF ON ANY HIGH LIGHTS FOR SATURDAY
NIGHT WITH WINDS DECREASING AND THEN TRENDS TOWARDS MODELS
SHIFTING SYSTEM FURTHER EAST. PRECIPITATION ENDING SUNDAY MORNING
TEMPERATURES IN THE 20S AND 30S FOR DAYTIME HIGHS. KEPT COOLER
TEMPERATURES OVER SNOW COVER THROUGH MONDAY. POSSIBILITY OF FOG
SUNDAY MORNING AND MONDAY NIGHT TUESDAY MORNING WITH MELTING SNOW.
COULD BE SOME JET INDUCED SNOW SHOWERS TUESDAY IN FAST NORTHWEST
FLOW. UPPER JET CURLS NORTH WEDNESDAY AND PACIFIC AIR MOVES INTO
FORECAST AREA. NICE WARMING TREND WITH TEMPERATURES RISING INTO
THE UPPER 40S NORTHEAST TO AROUND 60 SOUTHWEST AND WEST. GENERALLY
DRY AFTER TUESDAY.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SATURDAY NIGHT)
ISSUED AT 1153 PM CST FRI MAR 8 2013
SOLATED THUNDERSTORMS ARE EXPECTED IN EXTREME SOUTHWEST NEBRASKA
NEAR A SURFACE TROUGH AND WARM FRONT. AT THIS TIME...IT APPEARS THAT
CELLS THAT HAVE DEVELOPED ALREADY WILL PASS A LITTLE EAST OF LBF AND
DISSIPATE BEFORE GOING VERY FAR. WIDESPREAD LIGHT RAIN OR DRIZZLE
DEVELOPING NORTH AND WEST OF BBW-LBF IS LIKELY TO SPREAD WESTWARD AS
IT MOVES NORTH...AND IT WILL PROBABLY REACH VTN 08-10Z. BY ABOUT
12Z...A BAND OF PRECIPITATION IS EXPECTED TO DEVELOP NORTH AND WEST
OF AN ONL-OGA LINE. INITIALLY...IT WILL PROBABLY BE RAIN OR A
RAIN/SNOW MIX CHANGING TO SNOW BY ABOUT 14Z AND CONTINUING THROUGH
THE DAY SATURDAY. IN CENTRAL THROUGH SOUTHWEST NEBRASKA...SNOW IS
NOT EXPECTED BEFORE 00Z.
&&
.LBF WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY UNTIL 7 AM CDT /6 AM MDT/ SUNDAY FOR
NEZ006-008-025-026-036-057-058-069.
WINTER STORM WARNING UNTIL 7 AM CDT /6 AM MDT/ SUNDAY FOR NEZ004-
005-022>024-035-056-094.
&&
$$
UPDATE...CDC
SYNOPSIS...POWER
SHORT TERM...JACOBS
LONG TERM...POWER
AVIATION...SPRINGER
AREA FORECAST DISCUSSION
NWS BINGHAMTON NY
439 AM EST SAT MAR 9 2013
.SYNOPSIS...
HIGH PRESSURE WILL PROVIDE CLEAR SKIES AND MODERATING TEMPERATURES
THROUGH THE WEEKEND. A COLD FRONT IS EXPECTED TO APPROACH THE REGION
MONDAY NIGHT AND BRING THE AREA SCATTERED RAIN SHOWERS BY LATE MONDAY
AFTERNOON. TEMPERATURES WILL FALL BACK TO MORE SEASONAL VALUES BY
THE MIDDLE OF THE WEEK.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
330 AM UPDATE...
HIPRES WL DOMINATE THE WX TDA. 1030MB SFC HIGH WL BUILD EAST INTO
NERN U.S. THIS AFTN. UPR-LVL RIDGING OCCURRING BTWN H5 LOW SPINNING
OVR WRN ATLANTIC AND DIGGING INTO 4-CRNRS REGION. THIS HIGH ALOFT WL
INFLUENCE THE AREA WX OVR THE WEEKEND AND LEAD TO SUBSIDENCE TDA
WITH SUNNY SKIES EXPECTED.
H9 TEMPS INCRS FM -2C TO -4C TO +3C ACRS NEPA AND NR 0C OVR THE LK
PLAIN. THESE TEMPS WL YIELD HIGHS FM ARND 40F ACRS NRN ZONES TO ARND
50F OVR SRN ZONES. WITH LGT WINDS EXPECTED AND SUNNY SKIES THIS AFTN
DO NOT THINK 50S ARE OUT OF THE QUESTION UNDER STRENGTHENING MARCH
SUN. THUS FOR MAX TEMP GRIDS HV BUMPED LAV NUMBERS UP BY A DEGREE OR
TWO.
HIGH CIRRUS WL BEGIN TO OVRSPRD THE REGION FM THE WEST BY 00Z SUNDAY
PER LATEST GEM CLD FIELDS.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH MONDAY NIGHT/...
330 AM UPDATE...
CIRRUS WL THICKEN UP OVRNGT AS SUN GOES DOWN AND EVENTUALLY LEAD TO
PCLDY SKIES BY 12Z SUNDAY. DEPENDING ON HOW THICK CIRRUS WL BE
POTENTIAL LOOKS TO EXIST FOR RIDGE/VLY SPLIT IN TEMPS WITH FCST MINS
EXPECTED TO BE LWR 20S IN DEEPEST VLYS AND ARND 30 ON RIDGETOPS.
LEE-SIDE CYCLOGENESIS OCCURS THIS WEEKEND AS H5 LOW CROSSES
FRONT-RANGE. UL SYSTEM WL STEER SFC LOW EVER CLSR TO CWA THO WL
STILL RMN FAR ENUF BACK TO OUR WEST ON SUNDAY TO ALLOW HIPRES TO
CONT ITS GRIP ON THE REGION. H5 HEIGHTS APPCHG 570 SUN AFTN WL ALLOW
TEMPS TO RISE INTO THE 50S AREAWIDE. WITH SW FLOW IN THE BL AND H9
TEMPS APPCHG 7C TO 8C IN THE LK PLAIN SUN AFTN CANNOT RULE OUT UPR
50S IN NRN ZONES THUS HV RAISED HIGHS INTO THE MID-50S FOLLOWING
MAV/GMOS NUMBERS.
LATEST MODELS ADVERTISING SLOWING DOWN OF SYSTEM AND DELAY PCPN FM
ENTERING CWA UNTIL MON AFTN AT THE EARLIEST. 12Z EURO AND 00Z NAM12
INDICATE RAIN WL BE DELAYED UNTIL AFT 00Z TUE THUS HV SLOWED TIMING
OF POPS DOWN DRG THE DAY MONDAY WITH ONLY CHC POPS EXPECTED AFT 18Z
MONDAY. SFC BNDRY EXPECTED TO RMN BACK TO THE WEST ON MONDAY WITH
SRLY FLOW WARMING TEMPS TO NR 50 ONCE AGAIN UNDER CLDY SKIES.
MAIN FROPA OCCURS MON NGT/TUE MRNG, THUS HV BUMPED POPS TO 70% DRG
THIS TIME WITH RAIN EXPECTED. QPF AMNTS LOOK TO AVG ANYWHERE FM
0.50-0.75 INCHES BY 12Z TUESDAY PER LATEST EURO THO SLIGHTLY HIGHER
ON 00Z GFS/NAM. TIMING OF FNT WL PLAY A ROLE IN PTYPE WITH DELAYED
FROPA LEADING TO ALL RAIN MON NGT THEREFORE HV BACKED OFF ON RA/SN
MIX UNTIL CLOSER TO 09Z. 00Z EURO IS EVEN SLOWER THAN 12Z RUN BY
ABOUT 6 HRS. TRENDS INDICATING THAT IMPENDING SYSTEM WL SLOW DOWN
EVEN FURTHER AND LATER SHIFTS WL HV TO MONITOR PROGRESS.
&&
.LONG TERM /TUESDAY THROUGH FRIDAY/...
330 AM UPDATE...MINOR TWEEKS TO MED RNG BASED ON LATEST HPC
GUIDANCE...BUT OVERALL GIST OF FCST REMAINS UNCHANGED. PREV BLO...
2 PM UPDATE... FOLLOWED HPC GUIDANCE. BEST SHOT FOR PRECIPITATION
WILL COME EARLY IN THE PERIOD AS A COLD FRONT MOVES THROUGH MONDAY
NIGHT. MAY END AS SOME LIGHT SNOW...ESPECIALLY OVER THE HIGHER
TERRAIN EARLY TUESDAY MORNING. PREFERRED THE MORE UNSETTLED HPC
GUIDANCE (MORE EURO BASED) THAN THE GFS. THIS SOLUTION SHOWS A
TROF...COLDER AIR...AND SNOW SHOWERS THROUGH MID-WEEK. THE GFS IS
MORE ZONAL (NORTHWEST FLOW) WITH VARIOUS SHORT WAVES BEFORE A TROF
DEVELOPS IN THE EAST BY THE END OF THE WEEK.
&&
.AVIATION /10Z SATURDAY THROUGH WEDNESDAY/...
430 AM UPDATE...AREA OF LOW CLD/STRATUS HAS DVLPD ACRS THE ERN
FINGER LAKES. 1000-950 RUC RH APPEARS TO CAPTURE THIS...SUGGESTING
THAT THE WRN PERIPHERY COULD BRUSH ITH...AND HAVE ADDED POTNL IFR
FOR EARLY THIS MRNG THERE. IF THIS AREA HOLDS TOGETHER AS IT
DROPS SWD IT COULD AFFECT BGM TWDS 12Z. PREV BLO...
330 AM UPDATE...ADDED POTNL FOR IFR AT SYR THIS MRNG AS PATCHY
STRATUS/FOG HAS DVLPD SE OF LAKE ONTARIO. PREV BLO...
VFR WILL PREVAIL THRU 06Z SUN WITH SKC TO BKN250 XPCTD. PATCHY
LOW LVL STRATUS COULD DVLP TWDS DAYBREAK OVER PORTIONS OF CNTRL NY
BUT PROBS TOO LOW TO INCLUDE IN TAFS. WINDS TDA N TO NW 5-10
KTS...BECMG E TO SE TNGT ARND 5 KTS.
.OUTLOOK...
SAT NIGHT/SUN...VFR.
SUN NGT TO MON...MVFR IN -SHRA.
MON NGT TO TUE...MVFR/IFR WITH RAIN CHANGING TO SNOW.
WED...MVFR POSSIBLE ESPECIALLY CNY TERMINALS IN SNOW SHOWERS.
&&
.BGM WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NY...NONE.
&&
$$
SYNOPSIS...PVN
NEAR TERM...PVN
SHORT TERM...PVN
LONG TERM...HEDEN
AVIATION...
AREA FORECAST DISCUSSION
NWS SIOUX FALLS SD
1036 PM CST FRI MAR 8 2013
.DISCUSSION.../ISSUED AT 1010 PM CST/
PRECIPITATION BEGINNING TO EXPAND ACROSS THE AREA WITHS STRONG MID
LEVEL WARM AIR ADVECTION. TEMPERATURES ACROSS THE CWA HAVE GENERALLY
RISEN ABOVE FREEZING AT THIS POINT. THE RAP SEEMS TO HAVE THE
BEST HANDLE ON THE CURRENT SURFACE TEMPERATURES...AND IT SUGGESTS
MOST OF OUR NORTH STAYS JUST ABOVE FREEZING THROUGH THE NIGHT. THUS
THINKING MAINLY PLAIN RAIN...ALTHOUGH SOME ICY SPOTS ARE STILL
POSSIBLE ALONG THE HIGHWAY 14 CORRIDOR WHERE TEMPERATURES WILL FLIRT
WITH THE FREEZING MARK TROUGH THE NIGHT. STARTING TO SEE SOME
THUNDER ACROSS NORTHEAST NEBRASKA...AND WITH ELEVATED INSTABILITY
MOVING INTO OUR AREA...THINK A FEW LIGHTNING STRIKES WILL BE
POSSIBLE...MAINLY ALONG AND SOUTH OF INTERSTATE 90.
MODELS COMING INTO BETTER AGREEMENT ON EVOLUTION OF THE SYSTEM
TOMORROW...ALTHOUGH UNCERTAINTY STILL EXISTS. NAM...GFS AND SREF ALL
SHOWING WHAT COULD BE AN INTENSE MID LEVEL FRONT WEST OF THE JAMES
RIVER WITH SOME ELEVATED INSTABILITY AS WELL. THUS THOUGHT IS WE
COULD SEE A NARROW INTENSE BAND OF SNOW SOMEWHERE OUT THERE...BEST
GUESS AT THIS POINT FROM AROUND GREGORY COUNTY TO BEADLE. AS THE
NORTHERN STREAM WAVE PUSHES SOUTHEAST EXPECT DRY AIR AND INCREASING
SUBSIDENCE TO ENCROACH FROM THE NORTHWEST DURING THE AFTERNOON AND
EVENING. THIS SHOULD ACT TO DISSIPATE THIS BAND AS IT PUSHES OFF
SOUTHEAST. HOWEVER AS THE SOUTHERN STREAM WAVE AND PV ANOMALY EJECT
INTO THE CENTRAL PLAINS...EXPECT THE BAND TO REFORM FROM CENTRAL
NEBRASKA TO NORTHWEST IOWA. THIS WILL ALSO LIKELY BE A SOMEWHAT
NARROW CORRIDOR OF MODERATE TO POTENTIALLY HEAVY SNOW FOR SATURDAY
NIGHT. SO...CURRENT THOUGHTS ARE FOR LIGHT ICING ACROSS OUR FAR
NORTH AND ALSO WEST...GIVING WAY TO 3 TO 6 INCHES OF SNOW WEST OF
THE JAMES RIVER IN THAT INITIAL BAND. COULD EVEN SEE ISOLATED HIGHER
AMOUNTS...AND FUTURE SHIFTS WILL HAVE TO MONITOR NEW MODEL RUNS AND
POSSIBLY CONSIDER UPGRADING A FEW OF THOSE COUNTIES TO WARNINGS.
ANOTHER AREA OF 2 TO 6 INCHES SEEMS PROBABLE FROM YANKTON EAST INTO
NORTHWEST IOWA WITH THE SECOND BAND THAT FORMS. AGAIN ISOLATED
HIGHER AMOUNTS WILL BE POSSIBLE THERE AS WELL. PRETTY CONFIDENT WE
WILL NEED AN ADVISORY IN THAT AREA TOMORROW NIGHT...BUT CONFIDENCE
WAS TOO LOW FOR A WATCH. WINDS WILL PICK UP SATURDAY NIGHT INTO
SUNDAY LIKELY CREATING BLOWING AND DRIFTING ISSUES WITH ANY SNOW
THAT FALLS. SO FUTURE SHIFTS WILL ALSO HAVE TO DECIDE IF SNOW
AMOUNTS WILL BE HIGH ENOUGH...THAT COMBINED WITH THE WINDS...WOULD
WARRANT A WARNING FOR NORTHWEST IOWA. IN BETWEEN THESE TWO
BANDS...GENERALLY EXPECTING AN INCH OR TWO OF SNOW.
IN SUMMARY...MAINLY RAIN TONIGHT...CHANGING TO SNOW FROM NORTHWEST
TO SOUTHEAST TOMORROW INTO TOMORROW EVENING...ROUGHLY AFTER 9 AM
HURON...AFTER 1 PM MITCHELL...AFTER 6 PM SIOUX FALLS AND AFTER 9 PM
SIOUX CITY. EXPECTING TWO BANDS OF POTENTIALLY UP TO 6 INCHES OF
SNOW...ONE WEST OF THE JAMES RIVER AND ONE ACROSS NORTHWEST
IOWA...AND LESS IN BETWEEN. WITH THAT SAID...UNCERTAINTY STILL
EXISTS IN PLACEMENT OF THESE BANDS...AND WILL DEPEND ON STRENGTH OF
BOTH THE NORTHERN AND SOUTHERN STREAM. NEW 0Z GFS AND 0Z GEM HAVE
GONE AGAINST THE 12Z EC...0Z NAM AND 21Z SREF...IN THAT THEY ARE
SLIGHTLY FURTHER NORTH WITH BOTH BANDS...SUGGESTING A BIT MORE SNOW
FOR SIOUX FALLS. THUS STILL A FLUID SITUATION THAT WILL HAVE TO BE
MONITORED CLOSELY TONIGHT AND TOMORROW. CURRENT FORECAST FAVORS THE
MORE SOUTHERN SREF...NAM AND EC. /CHENARD
.PREVIOUS DISCUSSION.../ISSUED AT 253 PM CST/
QUITE A LOT OF CONVECTION IN THE DESERT SOUTHWEST WITH THE COMPACT
UPPER LEVEL LOW PRESSURE THAT WILL SOON BE AFFECTING OUR PART OF THE
COUNTRY. AS THIS WAVE MOVES INTO THE FOUR CORNERS REGION TONIGHT
SOUTHERLY FLOW WILL INCREASE ACROSS THE PLAINS. WITH DECENT LAPSE
RATES ALOFT AND VERY STRONG THERMAL/MOISTURE ADVECTION IN THE MID
LEVELS SUSPECT RAIN WILL DEVELOP QUICKLY TONIGHT OVER NEBRASKA INTO
SOUTH DAKOTA...IOWA AND MINNESOTA. THE LEAD WAVE CAUSING THIS
PRECIPITATION WILL SWING A DRY SLOT NORTHWARD LATE TONIGHT INTO
TOMORROW MORNING WHICH COULD SHUT DOWN THE SOUTHEAST HALF OF THE CWA
FOR AWHILE ON SATURDAY MORNING AND EARLY AFTERNOON AS SATURATION
ALOFT IS LOST AND TEMPERATURES LOWER ARE NOT COLD ENOUGH. RAINFALL
AMOUNTS TONIGHT IN MANY LOCATIONS LIKELY A QUARTER TO A HALF AN
INCH. WILL GO WITH A WINTER WEATHER ADVISORY FROM CHAMBERLAIN TO
HURON TO MARSHALL STARTING TONIGHT AND CONTINUING THROUGH SATURDAY
AFTERNOON. THE MAIN THREAT WILL BE FREEZING RAIN FROM ABOUT MIDNIGHT
THROUGH SUNRISE SATURDAY MORNING WHERE A TENTH TO TWO TENTHS OF AN
INCH OF ICING WILL BE POSSIBLE. WILL CONTINUE THROUGH THE AFTERNOON
AS SNOW WILL LIKELY DEVELOP...POSSIBLY ACCUMULATING AN INCH OR
TWO...AND WINDS WILL SIGNIFICANTLY INCREASE WITH GUSTS TO ABOUT 40
MPH POSSIBLE. ON TOP OF THE PRECIPITATION TONIGHT THE SOUTHERN HALF
OF THE CWA...MAINLY SOUTH OF INTERSTATE 90...COULD HEAR A LITTLE
THUNDER.
AS THIS POTENT WAVE SWINGS ONTO THE PLAINS SATURDAY DYNAMIC COOLING
WILL BEGIN TO QUICKLY SHIFT COLDER AIR INTO THE MID AND LOW LEVELS
AND TRANSITION THIS COLD AIR FROM WEST TO EAST. FREEZING RAIN WILL
TRANSITION TO SNOW IN THE WEST IN THE MORNING THEN CHANGE TO SNOW
FROM ABOUT MARSHALL TO SIOUX FALLS TO YANKTON AROUND 600 PM...THEN
IN NW IA AROUND 900 PM. THE STRONGEST FORCING LOOKS TO OCCUR FROM
ABOUT 0Z THROUGH 9Z IN THE SOUTHERN THIRD OF THE CWA. RIGHT NOW
THINKING MAINLY 1 TO 3 INCHES OF SNOW MOST LOCATIONS BUT THE BAND
THAT DEVELOPS IN NORTHERN NEBRASKA INTO NORTHWEST IOWA WILL HAVE THE
POTENTIAL TO PRODUCE 6 INCHES OR MORE OF SNOW IN A FAIRLY SHORT
PERIOD OF TIME. WILL HAVE TO KEEP AN EYE ON THE POTENTIAL FOR
BLOWING SNOW ON SATURDAY NIGHT AND SUNDAY MORNING IF MORE SNOW
OCCURS THAN EXPECTED AS GUSTS TO AROUND 40 TO 45 MPH IS NOT OUT OF
THE QUESTION.
SUSPECT WHAT WILL HAPPEN ON SATURDAY IS THE WARM ADVECTION BAND IN
THE NORTHERN CWA WILL FALL APART RATHER THAN TRANSITION FROM WEST TO
EAST. WHEN THE COLD FRONT ALOFT SWINGS INTO NORTHERN NEBRASKA
SATURDAY AFTERNOON A NEW BAND OF PRECIPITATION WILL DEVELOP AND
BECOME THE DOMINANT FEATURE. TRIED TO GET THIS POINT ACROSS IN THE
GRIDS BUT NOT EASY TO ACCOMPLISH. THIS SECOND BAND WILL BE THE ONE
THAT COULD PRODUCE SOME HEAVY SNOW AND ITS LOCATION WILL BE VERY
IMPORTANT. MOST OF THE SNOWFALL WILL BE EAST OF THE CWA BY 12Z
SUNDAY WITH A COLD AND WINDY SUNDAY EXPECTED.
HIGH PRESSURE RIDGE AXIS SLIDES ACROSS THE REGION ON SUNDAY
NIGHT...BRINGING DYING WINDS AND DECREASING CLOUDS. THIS IN
CONJUNCTION WITH LOW LEVEL COLD AIR ADVECTION WILL RESULT IN A
CHILLY NIGHT WITH LOWS IN THE SINGLE DIGITS AND TEENS.
THE HIGH MOVES EASTWARD ON MONDAY AS A SURFACE TROUGH APPROACHES
FROM THE WEST. THIS WILL PUT MUCH OF OUR AREA IN A RETURNING
SOUTHERLY FLOW...AND TEMPERATURES WILL RESPOND IN LIKE...ESPECIALLY
IN OUR SOUTHWEST...WITH HIGHS INTO THE MID 40S OVER THAT THAT AREA.
BACK TO THE EAST READINGS WILL TAPER DOWN INTO THE 30S...WITH
TEMPERATURES A LITTLE TRICKY DEPENDENT ON WHERE FRESH SNOW COVER IS
IS IN PLACE WITH SAT/SUN STORM. THE SURFACE TROUGH/BOUNDARY BEGINS
TO SLIDE INTO THE WEST LATE IN THE AFTERNOON...THEN SLIDING ACROSS
THE AREA ON MONDAY NIGHT. THE ECMWF/GEM WANTING TO SPIT OUT A LITTLE
PRECIPITATION WITH THIS IN THE LATE AFTERNOON OR EVENING AS AN UPPER
LEVEL SHORTWAVE TRACKS FROM NORTH DAKOTA TO THE LOWER GREAT LAKES
REGION OVERNIGHT. AT THE SAME TIME...THE GFS/NAM KEEP IT DRY AND
DECIDED TO GO THAT WAY WITH MOISTURE LOOKING TO BE PRETTY LIMITED.
IN THE EXTENDED...TUESDAY THROUGH FRIDAY...MODELS IN GOOD AGREEMENT
ON KEEPING OUR AREA IN A NORTHWESTERLY UPPER LEVEL FLOW THROUGH THE
THE PERIOD. HOWEVER...MODELS ARE IN LESS IN AGREEMENT ON THE
MESOSCALE FEATURES...WITH LOOSE CONSENSUS ON POSSIBLE PRECIPITATION
SOMETIME IN THE WEDNESDAY AND FRIDAY TIME FRAME AND KEPT SMALL
CHANCE POPS IN FOR THOSE PERIODS. TEMPERATURES THROUGH THE EXTENDED
LOOK TO REMAIN AT OR ABOVE NORMALS FOR THIS TIME OF YEAR.
&&
.AVIATION.../FOR THE 06Z TAF ISSUANCE/
MVFR CEILINGS WILL CONTINUE TO EXPAND ACROSS THE CWA TONIGHT AND
WILL BECOME IFR ACROSS THE ENTIRE AREA BY 12Z SATURDAY. WIDESPREAD
RAIN IS ALSO EXPECTED OVERNIGHT MIXING WITH FREEZING RAIN AND
CHANGING TO SNOW WEST OF INTERSTATE 29 DURING THE DAY ON SATURDAY
AND EAST OF INTERSTATE 29 AFTER 00Z SUNDAY. VISIBILITIES WILL DROP
BELOW ONE MILE AT TIMES...ESPECIALLY IN THE SNOW ON SATURDAY. GUSTY
NORTH WINDS OF 20 TO 30 KNOTS WILL DEVELOP WEST OF INTERSTATE 29 BY
SATURDAY AFTERNOON AND PERSIST THROUGH 06Z SUNDAY.
&&
.FSD WATCHES/WARNINGS/ADVISORIES...
SD...WINTER WEATHER ADVISORY UNTIL 6 PM CST SATURDAY FOR
SDZ038>040-050-052-053-057-058-063.
MN...WINTER WEATHER ADVISORY UNTIL 6 PM CST SATURDAY FOR MNZ071-072.
IA...NONE.
NE...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS SIOUX FALLS SD
1012 PM CST FRI MAR 8 2013
.DISCUSSION.../ISSUED AT 1010 PM CST/
PRECIPITATION BEGINNING TO EXPAND ACROSS THE AREA WITHS STRONG MID
LEVEL WARM AIR ADVECTION. TEMPERATURES ACROSS THE CWA HAVE GENERALLY
RISEN ABOVE FREEZING AT THIS POINT. THE RAP SEEMS TO HAVE THE
BEST HANDLE ON THE CURRENT SURFACE TEMPERATURES...AND IT SUGGESTS
MOST OF OUR NORTH STAYS JUST ABOVE FREEZING THROUGH THE NIGHT. THUS
THINKING MAINLY PLAIN RAIN...ALTHOUGH SOME ICY SPOTS ARE STILL
POSSIBLE ALONG THE HIGHWAY 14 CORRIDOR WHERE TEMPERATURES WILL FLIRT
WITH THE FREEZING MARK TROUGH THE NIGHT. STARTING TO SEE SOME
THUNDER ACROSS NORTHEAST NEBRASKA...AND WITH ELEVATED INSTABILITY
MOVING INTO OUR AREA...THINK A FEW LIGHTNING STRIKES WILL BE
POSSIBLE...MAINLY ALONG AND SOUTH OF INTERSTATE 90.
MODELS COMING INTO BETTER AGREEMENT ON EVOLUTION OF THE SYSTEM
TOMORROW...ALTHOUGH UNCERTAINTY STILL EXISTS. NAM...GFS AND SREF ALL
SHOWING WHAT COULD BE AN INTENSE MID LEVEL FRONT WEST OF THE JAMES
RIVER WITH SOME ELEVATED INSTABILITY AS WELL. THUS THOUGHT IS WE
COULD SEE A NARROW INTENSE BAND OF SNOW SOMEWHERE OUT THERE...BEST
GUESS AT THIS POINT FROM AROUND GREGORY COUNTY TO BEADLE. AS THE
NORTHERN STREAM WAVE PUSHES SOUTHEAST EXPECT DRY AIR AND INCREASING
SUBSIDENCE TO ENCROACH FROM THE NORTHWEST DURING THE AFTERNOON AND
EVENING. THIS SHOULD ACT TO DISSIPATE THIS BAND AS IT PUSHES OFF
SOUTHEAST. HOWEVER AS THE SOUTHERN STREAM WAVE AND PV ANOMALY EJECT
INTO THE CENTRAL PLAINS...EXPECT THE BAND TO REFORM FROM CENTRAL
NEBRASKA TO NORTHWEST IOWA. THIS WILL ALSO LIKELY BE A SOMEWHAT
NARROW CORRIDOR OF MODERATE TO POTENTIALLY HEAVY SNOW FOR SATURDAY
NIGHT. SO...CURRENT THOUGHTS ARE FOR LIGHT ICING ACROSS OUR FAR
NORTH AND ALSO WEST...GIVING WAY TO 3 TO 6 INCHES OF SNOW WEST OF
THE JAMES RIVER IN THAT INITIAL BAND. COULD EVEN SEE ISOLATED HIGHER
AMOUNTS...AND FUTURE SHIFTS WILL HAVE TO MONITOR NEW MODEL RUNS AND
POSSIBLY CONSIDER UPGRADING A FEW OF THOSE COUNTIES TO WARNINGS.
ANOTHER AREA OF 2 TO 6 INCHES SEEMS PROBABLE FROM YANKTON EAST INTO
NORTHWEST IOWA WITH THE SECOND BAND THAT FORMS. AGAIN ISOLATED
HIGHER AMOUNTS WILL BE POSSIBLE THERE AS WELL. PRETTY CONFIDENT WE
WILL NEED AN ADVISORY IN THAT AREA TOMORROW NIGHT...BUT CONFIDENCE
WAS TOO LOW FOR A WATCH. WINDS WILL PICK UP SATURDAY NIGHT INTO
SUNDAY LIKELY CREATING BLOWING AND DRIFTING ISSUES WITH ANY SNOW
THAT FALLS. SO FUTURE SHIFTS WILL ALSO HAVE TO DECIDE IF SNOW
AMOUNTS WILL BE HIGH ENOUGH...THAT COMBINED WITH THE WINDS...WOULD
WARRANT A WARNING FOR NORTHWEST IOWA. IN BETWEEN THESE TWO
BANDS...GENERALLY EXPECTING AN INCH OR TWO OF SNOW.
IN SUMMARY...MAINLY RAIN TONIGHT...CHANGING TO SNOW FROM NORTHWEST
TO SOUTHEAST TOMORROW INTO TOMORROW EVENING...ROUGHLY AFTER 9 AM
HURON...AFTER 1 PM MITCHELL...AFTER 6 PM SIOUX FALLS AND AFTER 9 PM
SIOUX CITY. EXPECTING TWO BANDS OF POTENTIALLY UP TO 6 INCHES OF
SNOW...ONE WEST OF THE JAMES RIVER AND ONE ACROSS NORTHWEST
IOWA...AND LESS IN BETWEEN. WITH THAT SAID...UNCERTAINTY STILL
EXISTS IN PLACEMENT OF THESE BANDS...AND WILL DEPEND ON STRENGTH OF
BOTH THE NORTHERN AND SOUTHERN STREAM. NEW 0Z GFS AND 0Z GEM HAVE
GONE AGAINST THE 12Z EC...0Z NAM AND 21Z SREF...IN THAT THEY ARE
SLIGHTLY FURTHER NORTH WITH BOTH BANDS...SUGGESTING A BIT MORE SNOW
FOR SIOUX FALLS. THUS STILL A FLUID SITUATION THAT WILL HAVE TO BE
MONITORED CLOSELY TONIGHT AND TOMORROW. CURRENT FORECAST FAVORS THE
MORE SOUTHERN SREF...NAM AND EC. /CHENARD
.PREVIOUS DISCUSSION.../ISSUED AT 253 PM CST/
QUITE A LOT OF CONVECTION IN THE DESERT SOUTHWEST WITH THE COMPACT
UPPER LEVEL LOW PRESSURE THAT WILL SOON BE AFFECTING OUR PART OF THE
COUNTRY. AS THIS WAVE MOVES INTO THE FOUR CORNERS REGION TONIGHT
SOUTHERLY FLOW WILL INCREASE ACROSS THE PLAINS. WITH DECENT LAPSE
RATES ALOFT AND VERY STRONG THERMAL/MOISTURE ADVECTION IN THE MID
LEVELS SUSPECT RAIN WILL DEVELOP QUICKLY TONIGHT OVER NEBRASKA INTO
SOUTH DAKOTA...IOWA AND MINNESOTA. THE LEAD WAVE CAUSING THIS
PRECIPITATION WILL SWING A DRY SLOT NORTHWARD LATE TONIGHT INTO
TOMORROW MORNING WHICH COULD SHUT DOWN THE SOUTHEAST HALF OF THE CWA
FOR AWHILE ON SATURDAY MORNING AND EARLY AFTERNOON AS SATURATION
ALOFT IS LOST AND TEMPERATURES LOWER ARE NOT COLD ENOUGH. RAINFALL
AMOUNTS TONIGHT IN MANY LOCATIONS LIKELY A QUARTER TO A HALF AN
INCH. WILL GO WITH A WINTER WEATHER ADVISORY FROM CHAMBERLAIN TO
HURON TO MARSHALL STARTING TONIGHT AND CONTINUING THROUGH SATURDAY
AFTERNOON. THE MAIN THREAT WILL BE FREEZING RAIN FROM ABOUT MIDNIGHT
THROUGH SUNRISE SATURDAY MORNING WHERE A TENTH TO TWO TENTHS OF AN
INCH OF ICING WILL BE POSSIBLE. WILL CONTINUE THROUGH THE AFTERNOON
AS SNOW WILL LIKELY DEVELOP...POSSIBLY ACCUMULATING AN INCH OR
TWO...AND WINDS WILL SIGNIFICANTLY INCREASE WITH GUSTS TO ABOUT 40
MPH POSSIBLE. ON TOP OF THE PRECIPITATION TONIGHT THE SOUTHERN HALF
OF THE CWA...MAINLY SOUTH OF INTERSTATE 90...COULD HEAR A LITTLE
THUNDER.
AS THIS POTENT WAVE SWINGS ONTO THE PLAINS SATURDAY DYNAMIC COOLING
WILL BEGIN TO QUICKLY SHIFT COLDER AIR INTO THE MID AND LOW LEVELS
AND TRANSITION THIS COLD AIR FROM WEST TO EAST. FREEZING RAIN WILL
TRANSITION TO SNOW IN THE WEST IN THE MORNING THEN CHANGE TO SNOW
FROM ABOUT MARSHALL TO SIOUX FALLS TO YANKTON AROUND 600 PM...THEN
IN NW IA AROUND 900 PM. THE STRONGEST FORCING LOOKS TO OCCUR FROM
ABOUT 0Z THROUGH 9Z IN THE SOUTHERN THIRD OF THE CWA. RIGHT NOW
THINKING MAINLY 1 TO 3 INCHES OF SNOW MOST LOCATIONS BUT THE BAND
THAT DEVELOPS IN NORTHERN NEBRASKA INTO NORTHWEST IOWA WILL HAVE THE
POTENTIAL TO PRODUCE 6 INCHES OR MORE OF SNOW IN A FAIRLY SHORT
PERIOD OF TIME. WILL HAVE TO KEEP AN EYE ON THE POTENTIAL FOR
BLOWING SNOW ON SATURDAY NIGHT AND SUNDAY MORNING IF MORE SNOW
OCCURS THAN EXPECTED AS GUSTS TO AROUND 40 TO 45 MPH IS NOT OUT OF
THE QUESTION.
SUSPECT WHAT WILL HAPPEN ON SATURDAY IS THE WARM ADVECTION BAND IN
THE NORTHERN CWA WILL FALL APART RATHER THAN TRANSITION FROM WEST TO
EAST. WHEN THE COLD FRONT ALOFT SWINGS INTO NORTHERN NEBRASKA
SATURDAY AFTERNOON A NEW BAND OF PRECIPITATION WILL DEVELOP AND
BECOME THE DOMINANT FEATURE. TRIED TO GET THIS POINT ACROSS IN THE
GRIDS BUT NOT EASY TO ACCOMPLISH. THIS SECOND BAND WILL BE THE ONE
THAT COULD PRODUCE SOME HEAVY SNOW AND ITS LOCATION WILL BE VERY
IMPORTANT. MOST OF THE SNOWFALL WILL BE EAST OF THE CWA BY 12Z
SUNDAY WITH A COLD AND WINDY SUNDAY EXPECTED.
HIGH PRESSURE RIDGE AXIS SLIDES ACROSS THE REGION ON SUNDAY
NIGHT...BRINGING DYING WINDS AND DECREASING CLOUDS. THIS IN
CONJUNCTION WITH LOW LEVEL COLD AIR ADVECTION WILL RESULT IN A
CHILLY NIGHT WITH LOWS IN THE SINGLE DIGITS AND TEENS.
THE HIGH MOVES EASTWARD ON MONDAY AS A SURFACE TROUGH APPROACHES
FROM THE WEST. THIS WILL PUT MUCH OF OUR AREA IN A RETURNING
SOUTHERLY FLOW...AND TEMPERATURES WILL RESPOND IN LIKE...ESPECIALLY
IN OUR SOUTHWEST...WITH HIGHS INTO THE MID 40S OVER THAT THAT AREA.
BACK TO THE EAST READINGS WILL TAPER DOWN INTO THE 30S...WITH
TEMPERATURES A LITTLE TRICKY DEPENDENT ON WHERE FRESH SNOW COVER IS
IS IN PLACE WITH SAT/SUN STORM. THE SURFACE TROUGH/BOUNDARY BEGINS
TO SLIDE INTO THE WEST LATE IN THE AFTERNOON...THEN SLIDING ACROSS
THE AREA ON MONDAY NIGHT. THE ECMWF/GEM WANTING TO SPIT OUT A LITTLE
PRECIPITATION WITH THIS IN THE LATE AFTERNOON OR EVENING AS AN UPPER
LEVEL SHORTWAVE TRACKS FROM NORTH DAKOTA TO THE LOWER GREAT LAKES
REGION OVERNIGHT. AT THE SAME TIME...THE GFS/NAM KEEP IT DRY AND
DECIDED TO GO THAT WAY WITH MOISTURE LOOKING TO BE PRETTY LIMITED.
IN THE EXTENDED...TUESDAY THROUGH FRIDAY...MODELS IN GOOD AGREEMENT
ON KEEPING OUR AREA IN A NORTHWESTERLY UPPER LEVEL FLOW THROUGH THE
THE PERIOD. HOWEVER...MODELS ARE IN LESS IN AGREEMENT ON THE
MESOSCALE FEATURES...WITH LOOSE CONSENSUS ON POSSIBLE PRECIPITATION
SOMETIME IN THE WEDNESDAY AND FRIDAY TIME FRAME AND KEPT SMALL
CHANCE POPS IN FOR THOSE PERIODS. TEMPERATURES THROUGH THE EXTENDED
LOOK TO REMAIN AT OR ABOVE NORMALS FOR THIS TIME OF YEAR.
&&
.AVIATION.../FOR THE 00Z TAF ISSUANCE/
VFR CEILINGS THIS EVENING WILL GRADUALLY BECOME MVFR BY 06Z AND THEN
BECOME IFR 06Z THROUGH 00Z SUNDAY. LIGHT RAIN WILL BECOME WIDESPREAD
THIS EVENING WITH FREEZING RAIN POSSIBLE NORTH OF A HON-MWM LINE.
ISOLATED THUNDERSTORMS WILL DEVELOP ACROSS NORTHWEST IOWA AND
NORTHEAST NEBRASKA AFTER 06Z. BETWEEN 15Z AND 00Z ON SATURDAY...THE
RAIN AND FREEZING RAIN WILL GRADUALLY CHANGE TO SNOW WEST OF
INTERSTATE 29. VISIBILITIES WILL FREQUENTLY DROP BELOW 3 MILES AS
THE RAIN BECOMES WIDESPREAD TONIGHT.
&&
.FSD WATCHES/WARNINGS/ADVISORIES...
SD...WINTER WEATHER ADVISORY UNTIL 6 PM CST SATURDAY FOR
SDZ038>040- 050-052-053-057-058-063.
MN...WINTER WEATHER ADVISORY UNTIL 6 PM CST SATURDAY FOR MNZ071-072.
IA...NONE.
NE...NONE.
&&
$$
AREA FORECAST DISCUSSION...UPDATED
NWS NORTH PLATTE NE
719 AM CST SAT MAR 9 2013
.UPDATE...
ISSUED AT 700 AM CST SAT MAR 9 2013
NO NEW DATA WAS AVAILABLE FOR THE QPF FORECAST BUT INDICATIONS ARE
THE RAP13 IS VERIFYING ACROSS NRN NEB WITH OVER 1/2 INCH OF ICE AT
THE KVTN ASOS. AFTER SLOWING THE EASTERN PROGRESSION OF THE RAIN
CHANGE LINE USING THE RUC...NORTH WINDS HAVE INCREASED AND NOW THE
RAIN CHANGE LINE IS ROUGHLY FROM CHAPPELL TO THEDFORD TO AINSWORTH.
SO THE NAM MAY BE VERIFYING BETTER AND IT WAS USED IN THE NEW
FORECAST.
A NEW WIND FORECAST USING NAM...GEM...MET AND MAV GUIDANCE
PRODUCED GUSTS TO 50 MPH THIS AFTERNOON AND THIS EVENING WHICH IS
CONSISTENT WITH THE 60KT BARRIER JET FCST BY BOTH MODELS. THIS
STRUCTURE IS FCST TO SET UP ACROSS THE ERN PANHANDLE THIS MORNING
AND MOVE SLOWLY EAST THIS AFTN AND TONIGHT ACTING AS A FOCUS FOR
SNOW AND STRONG WINDS.
THERE IS NO CHANGE TO THE DYNAMICS. STRONG FRONTOGENESIS HANGS
UP ACROSS THE NORTHWEST TODAY AND DECAYS WHILE A NEW STRUCTURE
DEVELOPS FARTHER EAST THIS EVENING. THE RAP HAS COME IN LINE WITH
THE NAM AND ECM DEVELOPING THE NEW SNOW EAST OF THE FCST AREA
WHILE THE 06Z GFS HANGS IT UP ACROSS NCNTL AND SWRN NEB...VERY
TROUBLING. GIVEN THE VERY STRONG WINDS DEVELOPING...EVEN AN 1/2
INCH PER HOUR SNOWFALL RATE COULD PRODUCE BLIZZARD CONDITIONS.
THE SNOW SHOULD GRADUALLY END OVERNIGHT AND SUNDAY MORNING WEST TO
EAST WITH CLEARING SKIES TO FOLLOW. WINDY CONDITIONS CONTINUE
SUNDAY MORNING IN THE EAST.
UPDATE ISSUED AT 527 AM CST SAT MAR 9 2013
THE RAP13 MODEL SHOWS A SLOWER TRANSITION TO SNOW THAN THE NAM. IN
FACT THE RAP CARRIES A BROAD AREA OF FREEZING RAIN AHEAD OF THE
CHANGEOVER TO SNOW. THIS IS WELL SUPPORTED IN THE MODEL TEMPERATURE
FIELDS. SO A NEW FORECAST IS OUT WHICH HEIGHTENS THE THREAT OF
FREEZING RAIN.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 345 AM CST SAT MAR 9 2013
TWO ROUNDS OF THOUGHT WITH THE STORM. ONE IS FOR A STRONG FGEN
FORCED BAND OF SNOW DEVELOPING ACROSS NORTHWEST NEBRASKA TODAY
WHICH MOST SOLNS AGREE ON TO VARYING DEGREES. THE SECOND IS FOR
ANOTHER STRONG BAND OF SNOW TO DEVELOP ACROSS SOUTH CENTRAL
NEBRASKA TONIGHT AS THE FIRST BAND DECAYS. THE GEM REGIONAL AND
GFS ARE VERY FAR NORTHWEST WITH THIS BAND SIGNALING A WINTER
STORM FOR NCNTL NEB WHILE THE NAM AND ECM ARE SAFELY EAST OF THE
FCST AREA. A BLEND OF NAM...GEM AND ECM WERE USED FOR THE LATEST
FCST WHICH PROVIDES A WINTER STORM ACROSS THE NORTHWEST AND A
WINTER WEATHER ADVISORY ELSEWHERE.
HOWEVER THE NAM AND RAP SHOW A VERY STRONG BARRIER JET DEVELOPING
THIS EVENING STRETCHING NORTH-SOUTH ALONG AND WEST OF HIGHWAY 83
WHICH COULD EASILY SUPPORT A WINTER STORM IF THE FRONTOGENESIS
WAS APPROPRIATELY JUXTAPOSED. THIS IS NOT THE CASE AS THE NAM
SHOWS THE FGEN AND HEAVY QPF MOSTLY EAST OF THE FCST AREA. THE
RAP MEANWHILE NOSES THE PV1.5 ANOMALY INTO SRN NEB AT 02Z AND
DEVELOPS SOME HEAVY SNOW ACROSS SWRN NEB. THIS IS A CONCERN WHICH
WILL BE CLOSELY MONITORED.
THE STRONG BARRIER JET WILL EASILY SUPPORT 30 MPH WINDS WITH
GUSTS TO 45 MPH. IN FACT THE NAM AND RAP SHOW GUSTS TO 60 MPH AT
00Z-03Z...THE HEIGHT OF THE STORM ACROSS SWRN AND NCNTL NEB.
SO EVERYONE OUTSIDE OF THE WINTER STORM WARNING HAS BEEN PLACED
IN A WINTER WEATHER ADVISORY FOR 3 TO 5 INCHES OF SNOW AND 30 TO
45 MPH WINDS.
.LONG TERM...(SUNDAY THROUGH FRIDAY)
ISSUED AT 345 AM CST SAT MAR 9 2013
MAJOR SPRING/WINTER STORM WILL BE EXITING SUNDAY MORNING WITH
SOME LINGERING LIGHT SNOW ACROSS THE FAR EASTERN COUNTIES. WINDS
WILL CONTINUE TO BE GUSTY...AND WILL HIGHLIGHT PATCHY BLOWING
SNOW WHERE FALLING SNOW IS EXPECTED. PENDING TOTAL SNOW AND HOW
FLUFFY IT IS...MAY NEED TO CONTINUE BLOWING SNOW FURTHER WEST
EARLY SUNDAY. STILL QUESTIONING HOW FAR WEST THE HEAVY BAND OF
SNOW OVER CENTRAL NEB WILL BE.
SUNDAY HIGHS...WITH COLD HIGH PRESSURE BUILDING SOUTH ACROSS THE
NORTHERN PLAINS AND MUCH IF NOT ALL OF THE AREA EXPECTED TO SEE A
SNOW COVER...SHOULD HOLD CLOSE TO 30 DEGREES. ALTHOUGH THE SUN
WILL SPREADING FROM WEST TO EAST...WHICH SHOULD HELP TO START TO
MELT ROADWAYS.
SUNDAY NIGHT WITH AN ELONGATED HIGH ACROSS THE WESTERN
PLAINS...LIGHT WINDS AND MOSTLY CLEAR SKIES ALONG WITH SNOW
PACK...TEMPS SHOULD TANK. WIDESPREAD TEENS...WHICH MAY BE
CONSERVATIVE.
MONDAY INTO MID WEEK RIDGE BUILDS ACROSS THE WEST...WITH A TROUGH
TO PUSH ALONG THE NORTHERN STREAM...ACROSS SOUTHERN CANADA AND
THE GREAT LAKES. WEAK DISTURBANCE TO MOVE ALONG THE NW FLOW
ACROSS THE AREA...HOWEVER MOISTURE LIMITED AND DOUBT ANYTHING
WILL REACH THE GROUND AS TIMING IS A LITTLE SLOWER WITH PASSAGE
MORE OF A DAYTIME AND THE HEAT OF THE DAY SHOULD BE ENOUGH TO
KEEP ANYTHING FROM HITTING THE GROUND. ALSO EARLY IN THE WEEK AS
THE SNOW MELTS WILL NEED TO MONITOR FOR OVERNIGHT/MORNING FOG.
RIDGE EXPANDS AS THE WEEK CONTINUES...WITH STRONG WAA ALOFT WITH
THE WESTERN PART OF THE CWA SEEING DOUBLE DIGIT 850 TEMPS.
QUESTION WILL BE HOW LONG CAN THE SNOW REMAIN AND DAMPEN TEMPS.
GUIDANCE PUSHES HIGHS INTO THE 50S AND 60S FOR WEDNESDAY AND
THURSDAY. AS IS TYPICAL WITH MANY MARCH SNOW STORMS...EXPECT THIS
SNOW NOT TO STAY LONG. ALTHOUGH WEST WINDS ON THE LIGHT
SIDE...LESS THAN 15 MPH...SHOULD BE ENOUGH TO HELP MIX WITH THE
DOWNSLOPE COMPONENT AND HAVE FOLLOWED CLOSER TO GUIDANCE FOR THE
LATER HALF OF THE WEEK.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SUNDAY MORNING)
ISSUED AT 537 AM CST SAT MAR 9 2013
EXPECTING IFR/LIFR TO CONTINUE THROUGH 03Z THIS EVENING IN
SNOW...BLOWING SNOW...FOG...RAIN AND FREEZING RAIN. THEREAFTER AN
IMPROVEMENT TO MVFR/VFR SHOULD COMMENCE FROM NORTHWEST TO
SOUTHEAST. WINDS TODAY WILL INCREASE TO 36030G40KT AND DIMINISH
LATE THIS EVENING TO 34020G30KT BY 12Z SUNDAY.
&&
.LBF WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY UNTIL 7 AM CDT /6 AM MDT/ SUNDAY FOR
NEZ006-008-025-026-036-057-058-069.
WINTER WEATHER ADVISORY FROM NOON CST TODAY TO 7 AM CDT SUNDAY
FOR NEZ007-009-010-027>029-037-038-059-070-071.
WINTER STORM WARNING UNTIL 7 AM CDT /6 AM MDT/ SUNDAY FOR NEZ004-
005-022>024-035-056-094.
&&
$$
UPDATE...CDC
SHORT TERM...CDC
LONG TERM...MASEK
AVIATION...CDC
AREA FORECAST DISCUSSION...UPDATED
NWS NORTH PLATTE NE
540 AM CST SAT MAR 9 2013
.UPDATE...
ISSUED AT 527 AM CST SAT MAR 9 2013
THE RAP13 MODEL SHOWS A SLOWER TRANSITION TO SNOW THAN THE NAM. IN
FACT THE RAP CARRIES A BROAD AREA OF FREEZING RAIN AHEAD OF THE
CHANGEOVER TO SNOW. THIS IS WELL SUPPORTED IN THE MODEL TEMPERATURE
FIELDS. SO A NEW FORECAST IS OUT WHICH HEIGHTENS THE THREAT OF
FREEZING RAIN.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 345 AM CST SAT MAR 9 2013
TWO ROUNDS OF THOUGHT WITH THE STORM. ONE IS FOR A STRONG FGEN
FORCED BAND OF SNOW DEVELOPING ACROSS NORTHWEST NEBRASKA TODAY
WHICH MOST SOLNS AGREE ON TO VARYING DEGREES. THE SECOND IS FOR
ANOTHER STRONG BAND OF SNOW TO DEVELOP ACROSS SOUTH CENTRAL
NEBRASKA TONIGHT AS THE FIRST BAND DECAYS. THE GEM REGIONAL AND
GFS ARE VERY FAR NORTHWEST WITH THIS BAND SIGNALING A WINTER
STORM FOR NCNTL NEB WHILE THE NAM AND ECM ARE SAFELY EAST OF THE
FCST AREA. A BLEND OF NAM...GEM AND ECM WERE USED FOR THE LATEST
FCST WHICH PROVIDES A WINTER STORM ACROSS THE NORTHWEST AND A
WINTER WEATHER ADVISORY ELSEWHERE.
HOWEVER THE NAM AND RAP SHOW A VERY STRONG BARRIER JET DEVELOPING
THIS EVENING STRETCHING NORTH-SOUTH ALONG AND WEST OF HIGHWAY 83
WHICH COULD EASILY SUPPORT A WINTER STORM IF THE FRONTOGENESIS
WAS APPROPRIATELY JUXTAPOSED. THIS IS NOT THE CASE AS THE NAM
SHOWS THE FGEN AND HEAVY QPF MOSTLY EAST OF THE FCST AREA. THE
RAP MEANWHILE NOSES THE PV1.5 ANOMALY INTO SRN NEB AT 02Z AND
DEVELOPS SOME HEAVY SNOW ACROSS SWRN NEB. THIS IS A CONCERN WHICH
WILL BE CLOSELY MONITORED.
THE STRONG BARRIER JET WILL EASILY SUPPORT 30 MPH WINDS WITH
GUSTS TO 45 MPH. IN FACT THE NAM AND RAP SHOW GUSTS TO 60 MPH AT
00Z-03Z...THE HEIGHT OF THE STORM ACROSS SWRN AND NCNTL NEB.
SO EVERYONE OUTSIDE OF THE WINTER STORM WARNING HAS BEEN PLACED
IN A WINTER WEATHER ADVISORY FOR 3 TO 5 INCHES OF SNOW AND 30 TO
45 MPH WINDS.
.LONG TERM...(SUNDAY THROUGH FRIDAY)
ISSUED AT 345 AM CST SAT MAR 9 2013
MAJOR SPRING/WINTER STORM WILL BE EXITING SUNDAY MORNING WITH
SOME LINGERING LIGHT SNOW ACROSS THE FAR EASTERN COUNTIES. WINDS
WILL CONTINUE TO BE GUSTY...AND WILL HIGHLIGHT PATCHY BLOWING
SNOW WHERE FALLING SNOW IS EXPECTED. PENDING TOTAL SNOW AND HOW
FLUFFY IT IS...MAY NEED TO CONTINUE BLOWING SNOW FURTHER WEST
EARLY SUNDAY. STILL QUESTIONING HOW FAR WEST THE HEAVY BAND OF
SNOW OVER CENTRAL NEB WILL BE.
SUNDAY HIGHS...WITH COLD HIGH PRESSURE BUILDING SOUTH ACROSS THE
NORTHERN PLAINS AND MUCH IF NOT ALL OF THE AREA EXPECTED TO SEE A
SNOW COVER...SHOULD HOLD CLOSE TO 30 DEGREES. ALTHOUGH THE SUN
WILL SPREADING FROM WEST TO EAST...WHICH SHOULD HELP TO START TO
MELT ROADWAYS.
SUNDAY NIGHT WITH AN ELONGATED HIGH ACROSS THE WESTERN
PLAINS...LIGHT WINDS AND MOSTLY CLEAR SKIES ALONG WITH SNOW
PACK...TEMPS SHOULD TANK. WIDESPREAD TEENS...WHICH MAY BE
CONSERVATIVE.
MONDAY INTO MID WEEK RIDGE BUILDS ACROSS THE WEST...WITH A TROUGH
TO PUSH ALONG THE NORTHERN STREAM...ACROSS SOUTHERN CANADA AND
THE GREAT LAKES. WEAK DISTURBANCE TO MOVE ALONG THE NW FLOW
ACROSS THE AREA...HOWEVER MOISTURE LIMITED AND DOUBT ANYTHING
WILL REACH THE GROUND AS TIMING IS A LITTLE SLOWER WITH PASSAGE
MORE OF A DAYTIME AND THE HEAT OF THE DAY SHOULD BE ENOUGH TO
KEEP ANYTHING FROM HITTING THE GROUND. ALSO EARLY IN THE WEEK AS
THE SNOW MELTS WILL NEED TO MONITOR FOR OVERNIGHT/MORNING FOG.
RIDGE EXPANDS AS THE WEEK CONTINUES...WITH STRONG WAA ALOFT WITH
THE WESTERN PART OF THE CWA SEEING DOUBLE DIGIT 850 TEMPS.
QUESTION WILL BE HOW LONG CAN THE SNOW REMAIN AND DAMPEN TEMPS.
GUIDANCE PUSHES HIGHS INTO THE 50S AND 60S FOR WEDNESDAY AND
THURSDAY. AS IS TYPICAL WITH MANY MARCH SNOW STORMS...EXPECT THIS
SNOW NOT TO STAY LONG. ALTHOUGH WEST WINDS ON THE LIGHT
SIDE...LESS THAN 15 MPH...SHOULD BE ENOUGH TO HELP MIX WITH THE
DOWNSLOPE COMPONENT AND HAVE FOLLOWED CLOSER TO GUIDANCE FOR THE
LATER HALF OF THE WEEK.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SUNDAY MORNING)
ISSUED AT 537 AM CST SAT MAR 9 2013
EXPECTING IFR/LIFR TO CONTINUE THROUGH 03Z THIS EVENING IN
SNOW...BLOWING SNOW...FOG...RAIN AND FREEZING RAIN. THEREAFTER AN
IMPROVEMENT TO MVFR/VFR SHOULD COMMENCE FROM NORTHWEST TO
SOUTHEAST. WINDS TODAY WILL INCREASE TO 36030G40KT AND DIMINISH
LATE THIS EVENING TO 34020G30KT BY 12Z SUNDAY.
&&
.LBF WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY UNTIL 7 AM CDT /6 AM MDT/ SUNDAY FOR
NEZ006-008-025-026-036-057-058-069.
WINTER WEATHER ADVISORY FROM NOON CST TODAY TO 7 AM CDT SUNDAY
FOR NEZ007-009-010-027>029-037-038-059-070-071.
WINTER STORM WARNING UNTIL 7 AM CDT /6 AM MDT/ SUNDAY FOR NEZ004-
005-022>024-035-056-094.
&&
$$
UPDATE...CDC
SHORT TERM...CDC
LONG TERM...MASEK
AVIATION...CDC
AREA FORECAST DISCUSSION...UPDATED
NWS NORTH PLATTE NE
528 AM CST SAT MAR 9 2013
.UPDATE...
ISSUED AT 527 AM CST SAT MAR 9 2013
THE RAP13 MODEL SHOWS A SLOWER TRANSITION TO SNOW THAN THE NAM. IN
FACT THE RAP CARRIES A BROAD AREA OF FREEZING RAIN AHEAD OF THE
CHANGEOVER TO SNOW. THIS IS WELL SUPPORTED IN THE MODEL TEMPERATURE
FIELDS. SO A NEW FORECAST IS OUT WHICH HEIGHTENS THE THREAT OF
FREEZING RAIN.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 345 AM CST SAT MAR 9 2013
TWO ROUNDS OF THOUGHT WITH THE STORM. ONE IS FOR A STRONG FGEN
FORCED BAND OF SNOW DEVELOPING ACROSS NORTHWEST NEBRASKA TODAY
WHICH MOST SOLNS AGREE ON TO VARYING DEGREES. THE SECOND IS FOR
ANOTHER STRONG BAND OF SNOW TO DEVELOP ACROSS SOUTH CENTRAL
NEBRASKA TONIGHT AS THE FIRST BAND DECAYS. THE GEM REGIONAL AND
GFS ARE VERY FAR NORTHWEST WITH THIS BAND SIGNALING A WINTER
STORM FOR NCNTL NEB WHILE THE NAM AND ECM ARE SAFELY EAST OF THE
FCST AREA. A BLEND OF NAM...GEM AND ECM WERE USED FOR THE LATEST
FCST WHICH PROVIDES A WINTER STORM ACROSS THE NORTHWEST AND A
WINTER WEATHER ADVISORY ELSEWHERE.
HOWEVER THE NAM AND RAP SHOW A VERY STRONG BARRIER JET DEVELOPING
THIS EVENING STRETCHING NORTH-SOUTH ALONG AND WEST OF HIGHWAY 83
WHICH COULD EASILY SUPPORT A WINTER STORM IF THE FRONTOGENESIS
WAS APPROPRIATELY JUXTAPOSED. THIS IS NOT THE CASE AS THE NAM
SHOWS THE FGEN AND HEAVY QPF MOSTLY EAST OF THE FCST AREA. THE
RAP MEANWHILE NOSES THE PV1.5 ANOMALY INTO SRN NEB AT 02Z AND
DEVELOPS SOME HEAVY SNOW ACROSS SWRN NEB. THIS IS A CONCERN WHICH
WILL BE CLOSELY MONITORED.
THE STRONG BARRIER JET WILL EASILY SUPPORT 30 MPH WINDS WITH
GUSTS TO 45 MPH. IN FACT THE NAM AND RAP SHOW GUSTS TO 60 MPH AT
00Z-03Z...THE HEIGHT OF THE STORM ACROSS SWRN AND NCNTL NEB.
SO EVERYONE OUTSIDE OF THE WINTER STORM WARNING HAS BEEN PLACED
IN A WINTER WEATHER ADVISORY FOR 3 TO 5 INCHES OF SNOW AND 30 TO
45 MPH WINDS.
.LONG TERM...(SUNDAY THROUGH FRIDAY)
ISSUED AT 345 AM CST SAT MAR 9 2013
MAJOR SPRING/WINTER STORM WILL BE EXITING SUNDAY MORNING WITH
SOME LINGERING LIGHT SNOW ACROSS THE FAR EASTERN COUNTIES. WINDS
WILL CONTINUE TO BE GUSTY...AND WILL HIGHLIGHT PATCHY BLOWING
SNOW WHERE FALLING SNOW IS EXPECTED. PENDING TOTAL SNOW AND HOW
FLUFFY IT IS...MAY NEED TO CONTINUE BLOWING SNOW FURTHER WEST
EARLY SUNDAY. STILL QUESTIONING HOW FAR WEST THE HEAVY BAND OF
SNOW OVER CENTRAL NEB WILL BE.
SUNDAY HIGHS...WITH COLD HIGH PRESSURE BUILDING SOUTH ACROSS THE
NORTHERN PLAINS AND MUCH IF NOT ALL OF THE AREA EXPECTED TO SEE A
SNOW COVER...SHOULD HOLD CLOSE TO 30 DEGREES. ALTHOUGH THE SUN
WILL SPREADING FROM WEST TO EAST...WHICH SHOULD HELP TO START TO
MELT ROADWAYS.
SUNDAY NIGHT WITH AN ELONGATED HIGH ACROSS THE WESTERN
PLAINS...LIGHT WINDS AND MOSTLY CLEAR SKIES ALONG WITH SNOW
PACK...TEMPS SHOULD TANK. WIDESPREAD TEENS...WHICH MAY BE
CONSERVATIVE.
MONDAY INTO MID WEEK RIDGE BUILDS ACROSS THE WEST...WITH A TROUGH
TO PUSH ALONG THE NORTHERN STREAM...ACROSS SOUTHERN CANADA AND
THE GREAT LAKES. WEAK DISTURBANCE TO MOVE ALONG THE NW FLOW
ACROSS THE AREA...HOWEVER MOISTURE LIMITED AND DOUBT ANYTHING
WILL REACH THE GROUND AS TIMING IS A LITTLE SLOWER WITH PASSAGE
MORE OF A DAYTIME AND THE HEAT OF THE DAY SHOULD BE ENOUGH TO
KEEP ANYTHING FROM HITTING THE GROUND. ALSO EARLY IN THE WEEK AS
THE SNOW MELTS WILL NEED TO MONITOR FOR OVERNIGHT/MORNING FOG.
RIDGE EXPANDS AS THE WEEK CONTINUES...WITH STRONG WAA ALOFT WITH
THE WESTERN PART OF THE CWA SEEING DOUBLE DIGIT 850 TEMPS.
QUESTION WILL BE HOW LONG CAN THE SNOW REMAIN AND DAMPEN TEMPS.
GUIDANCE PUSHES HIGHS INTO THE 50S AND 60S FOR WEDNESDAY AND
THURSDAY. AS IS TYPICAL WITH MANY MARCH SNOW STORMS...EXPECT THIS
SNOW NOT TO STAY LONG. ALTHOUGH WEST WINDS ON THE LIGHT
SIDE...LESS THAN 15 MPH...SHOULD BE ENOUGH TO HELP MIX WITH THE
DOWNSLOPE COMPONENT AND HAVE FOLLOWED CLOSER TO GUIDANCE FOR THE
LATER HALF OF THE WEEK.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SATURDAY NIGHT)
ISSUED AT 1153 PM CST FRI MAR 8 2013
ISOLATED THUNDERSTORMS ARE EXPECTED IN EXTREME SOUTHWEST NEBRASKA
NEAR A SURFACE TROUGH AND WARM FRONT. AT THIS TIME...IT APPEARS THAT
CELLS THAT HAVE DEVELOPED ALREADY WILL PASS A LITTLE EAST OF LBF AND
DISSIPATE BEFORE GOING VERY FAR. WIDESPREAD LIGHT RAIN OR DRIZZLE
DEVELOPING NORTH AND WEST OF BBW-LBF IS LIKELY TO SPREAD WESTWARD AS
IT MOVES NORTH...AND IT WILL PROBABLY REACH VTN 08-10Z. BY ABOUT
12Z...A BAND OF PRECIPITATION IS EXPECTED TO DEVELOP NORTH AND WEST
OF AN ONL-OGA LINE. INITIALLY...IT WILL PROBABLY BE RAIN OR A
RAIN/SNOW MIX CHANGING TO SNOW BY ABOUT 14Z AND CONTINUING THROUGH
THE DAY SATURDAY. IN CENTRAL THROUGH SOUTHWEST NEBRASKA...SNOW IS
NOT EXPECTED BEFORE 00Z.
&&
.LBF WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY UNTIL 7 AM CDT /6 AM MDT/ SUNDAY FOR
NEZ006-008-025-026-036-057-058-069.
WINTER WEATHER ADVISORY FROM NOON CST TODAY TO 7 AM CDT SUNDAY
FOR NEZ007-009-010-027>029-037-038-059-070-071.
WINTER STORM WARNING UNTIL 7 AM CDT /6 AM MDT/ SUNDAY FOR NEZ004-
005-022>024-035-056-094.
&&
$$
UPDATE...CDC
SHORT TERM...CDC
LONG TERM...MASEK
AVIATION...SPRINGER
AREA FORECAST DISCUSSION
NWS BINGHAMTON NY
602 AM EST SAT MAR 9 2013
.SYNOPSIS...
HIGH PRESSURE WILL PROVIDE CLEAR SKIES AND MODERATING TEMPERATURES
THROUGH THE WEEKEND. A COLD FRONT IS EXPECTED TO APPROACH THE REGION
MONDAY NIGHT AND BRING THE AREA SCATTERED RAIN SHOWERS BY LATE MONDAY
AFTERNOON. TEMPERATURES WILL FALL BACK TO MORE SEASONAL VALUES BY
THE MIDDLE OF THE WEEK.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
6 AM UPDATE...
QUICK UPDATE TO ADD IN LOW STRATUS OVR FINGER LKS AS THAT HAS
DEVELOPED SINCE 08Z UNDER CALM WINDS AND LWRNG DWPT DEPRESSIONS.
EXPECT BY THE TIME MIXING STARTS LOW CLOUDS SHUD SCATTER OUT AND
LEAVE A SUNNY DAY ON TAP.
PREV DISCO BLO...
330 AM UPDATE...
HIPRES WL DOMINATE THE WX TDA. 1030MB SFC HIGH WL BUILD EAST INTO
NERN U.S. THIS AFTN. UPR-LVL RIDGING OCCURRING BTWN H5 LOW SPINNING
OVR WRN ATLANTIC AND DIGGING INTO 4-CRNRS REGION. THIS HIGH ALOFT WL
INFLUENCE THE AREA WX OVR THE WEEKEND AND LEAD TO SUBSIDENCE TDA
WITH SUNNY SKIES EXPECTED.
H9 TEMPS INCRS FM -2C TO -4C TO +3C ACRS NEPA AND NR 0C OVR THE LK
PLAIN. THESE TEMPS WL YIELD HIGHS FM ARND 40F ACRS NRN ZONES TO ARND
50F OVR SRN ZONES. WITH LGT WINDS EXPECTED AND SUNNY SKIES THIS AFTN
DO NOT THINK 50S ARE OUT OF THE QUESTION UNDER STRENGTHENING MARCH
SUN. THUS FOR MAX TEMP GRIDS HV BUMPED LAV NUMBERS UP BY A DEGREE OR
TWO.
HIGH CIRRUS WL BEGIN TO OVRSPRD THE REGION FM THE WEST BY 00Z SUNDAY
PER LATEST GEM CLD FIELDS.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH MONDAY NIGHT/...
330 AM UPDATE...
CIRRUS WL THICKEN UP OVRNGT AS SUN GOES DOWN AND EVENTUALLY LEAD TO
PCLDY SKIES BY 12Z SUNDAY. DEPENDING ON HOW THICK CIRRUS WL BE
POTENTIAL LOOKS TO EXIST FOR RIDGE/VLY SPLIT IN TEMPS WITH FCST MINS
EXPECTED TO BE LWR 20S IN DEEPEST VLYS AND ARND 30 ON RIDGETOPS.
LEE-SIDE CYCLOGENESIS OCCURS THIS WEEKEND AS H5 LOW CROSSES
FRONT-RANGE. UL SYSTEM WL STEER SFC LOW EVER CLSR TO CWA THO WL
STILL RMN FAR ENUF BACK TO OUR WEST ON SUNDAY TO ALLOW HIPRES TO
CONT ITS GRIP ON THE REGION. H5 HEIGHTS APPCHG 570 SUN AFTN WL ALLOW
TEMPS TO RISE INTO THE 50S AREAWIDE. WITH SW FLOW IN THE BL AND H9
TEMPS APPCHG 7C TO 8C IN THE LK PLAIN SUN AFTN CANNOT RULE OUT UPR
50S IN NRN ZONES THUS HV RAISED HIGHS INTO THE MID-50S FOLLOWING
MAV/GMOS NUMBERS.
LATEST MODELS ADVERTISING SLOWING DOWN OF SYSTEM AND DELAY PCPN FM
ENTERING CWA UNTIL MON AFTN AT THE EARLIEST. 12Z EURO AND 00Z NAM12
INDICATE RAIN WL BE DELAYED UNTIL AFT 00Z TUE THUS HV SLOWED TIMING
OF POPS DOWN DRG THE DAY MONDAY WITH ONLY CHC POPS EXPECTED AFT 18Z
MONDAY. SFC BNDRY EXPECTED TO RMN BACK TO THE WEST ON MONDAY WITH
SRLY FLOW WARMING TEMPS TO NR 50 ONCE AGAIN UNDER CLDY SKIES.
MAIN FROPA OCCURS MON NGT/TUE MRNG, THUS HV BUMPED POPS TO 70% DRG
THIS TIME WITH RAIN EXPECTED. QPF AMNTS LOOK TO AVG ANYWHERE FM
0.50-0.75 INCHES BY 12Z TUESDAY PER LATEST EURO THO SLIGHTLY HIGHER
ON 00Z GFS/NAM. TIMING OF FNT WL PLAY A ROLE IN PTYPE WITH DELAYED
FROPA LEADING TO ALL RAIN MON NGT THEREFORE HV BACKED OFF ON RA/SN
MIX UNTIL CLOSER TO 09Z. 00Z EURO IS EVEN SLOWER THAN 12Z RUN BY
ABOUT 6 HRS. TRENDS INDICATING THAT IMPENDING SYSTEM WL SLOW DOWN
EVEN FURTHER AND LATER SHIFTS WL HV TO MONITOR PROGRESS.
&&
.LONG TERM /TUESDAY THROUGH FRIDAY/...
330 AM UPDATE...MINOR TWEEKS TO MED RNG BASED ON LATEST HPC
GUIDANCE...BUT OVERALL GIST OF FCST REMAINS UNCHANGED. PREV BLO...
2 PM UPDATE... FOLLOWED HPC GUIDANCE. BEST SHOT FOR PRECIPITATION
WILL COME EARLY IN THE PERIOD AS A COLD FRONT MOVES THROUGH MONDAY
NIGHT. MAY END AS SOME LIGHT SNOW...ESPECIALLY OVER THE HIGHER
TERRAIN EARLY TUESDAY MORNING. PREFERRED THE MORE UNSETTLED HPC
GUIDANCE (MORE EURO BASED) THAN THE GFS. THIS SOLUTION SHOWS A
TROF...COLDER AIR...AND SNOW SHOWERS THROUGH MID-WEEK. THE GFS IS
MORE ZONAL (NORTHWEST FLOW) WITH VARIOUS SHORT WAVES BEFORE A TROF
DEVELOPS IN THE EAST BY THE END OF THE WEEK.
&&
.AVIATION /12Z SATURDAY THROUGH WEDNESDAY/...
430 AM UPDATE...AREA OF LOW CLD/STRATUS HAS DVLPD ACRS THE ERN
FINGER LAKES. 1000-950 RUC RH APPEARS TO CAPTURE THIS...SUGGESTING
THAT THE WRN PERIPHERY COULD BRUSH ITH...AND HAVE ADDED POTNL IFR
FOR EARLY THIS MRNG THERE. IF THIS AREA HOLDS TOGETHER AS IT
DROPS SWD IT COULD AFFECT BGM TWDS 12Z. PREV BLO...
330 AM UPDATE...ADDED POTNL FOR IFR AT SYR THIS MRNG AS PATCHY
STRATUS/FOG HAS DVLPD SE OF LAKE ONTARIO. PREV BLO...
VFR WILL PREVAIL THRU 06Z SUN WITH SKC TO BKN250 XPCTD. PATCHY
LOW LVL STRATUS COULD DVLP TWDS DAYBREAK OVER PORTIONS OF CNTRL NY
BUT PROBS TOO LOW TO INCLUDE IN TAFS. WINDS TDA N TO NW 5-10
KTS...BECMG E TO SE TNGT ARND 5 KTS.
.OUTLOOK...
SAT NIGHT/SUN...VFR.
SUN NGT TO MON...MVFR IN -SHRA.
MON NGT TO TUE...MVFR/IFR WITH RAIN CHANGING TO SNOW.
WED...MVFR POSSIBLE ESPECIALLY CNY TERMINALS IN SNOW SHOWERS.
&&
.BGM WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NY...NONE.
&&
$$
SYNOPSIS...PVN
NEAR TERM...PVN
SHORT TERM...PVN
LONG TERM...HEDEN
AVIATION...
AREA FORECAST DISCUSSION
NWS BISMARCK ND
856 AM CST SAT MAR 9 2013
.DISCUSSION...LATEST WATER VAPOR IMAGERY SHOWS THE NORTHERN STREAM
TROUGH NOW WORKING THROUGH NORTHWEST NORTH DAKOTA...WHILE THE
SOUTHERN STREAM UPPER LOW IS CIRCULATING OVER NORTHWEST NEW
MEXICO. RADAR IMAGERY AND LATEST RAP MODEL INDICATE LIGHT SNOW
ASSOCIATED WITH THE NORTHERN STREAM TROUGH WILL CONTINUE THROUGH
THE MORNING IN NORTH CENTRAL NORTH DAKOTA AND WANE THIS AFTERNOON
AS THE BEST LIFT SHUTS DOWN AND EXITS TO THE EAST. HAVE BUMPED
POPS TO CATEGORICAL FOR THE REST OF THE MORNING IN MOST OF THE
NORTH CENTRAL BASED ON RADAR AND SURFACE OBS. ALL INDICATIONS
ARE THAT THE NEXT AREA OF PRECIPITATION ASSOCIATED WITH THE
SOUTHERN STREAM LOW NOW IN SOUTH CENTRAL/SOUTHEAST SOUTH DAKOTA
WILL GET SHUNTED EAST AND REMAIN EAST OF OUR FORECAST AREA. WILL
CONTINUE TO ADVERTISE SLIGHT CHC POPS FOR SOME WAFFLING FURTHER
WEST BASED ON THE 06Z RUN OF THE GFS/ECMWF.
FOG WILL CONTINUE THROUGH THE MORNING WITH ISOLATED DENSE FOG
OVER THE NEXT HOUR OR TWO. NO OTHER CHANGES WERE MADE TO THE
CURRENT FORECAST.
&&
.AVIATION...WIDESPREAD FOG AND IFR CIGS AND IFR/MVFR VSBYS WILL
PREVAIL THROUGH MUCH OF THE MORNING WITH IMPROVING CONDITIONS
DURING THE EARLY AFTERNOON. EXPECT PERIODS OF LIGHT SNOW...MAINLY
AT KMOT THROUGH MID AFTERNOON.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
DISCUSSION...KS
AVIATION...KS/LTH
AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NWS RAPID CITY SD
855 AM MST SAT MAR 9 2013
.UPDATE...
ISSUED AT 855 AM MST SAT MAR 9 2013
15Z SURFACE ANALYSIS HAD LOW OVER SOUTHEAST CO WITH NEARLY
STATIONARY BOUNDARY INTO EASTERN ND. FIRST IMPULSE FROM STORM
SYSTEM BROUGHT A BRIEF PERIOD OF -FZRA TO SOUTH CENTRAL SD...BUT
CALLS TO SPOTTERS INDICATE CHANGEOVER TO SN HAS OCCURRED WITH 1-2
INCHES IN THE LAST COUPLE OF HOURS. 12Z RAP HAD A GOOD HANDLE ON
CURRENT SENSIBLE WEATHER. NARROW BAND OF -SN/SN WILL CONTINUE
THROUGH THIS AFTERNOON OVER SOUTH CENTRAL SD AS MAIN IMPULSE MOVES
NORTHEAST INTO THE CENTRAL PLAINS. SNOW COINCIDENT WITH STRONG
BAND OF 850-700MB FRONTOGENESIS...NORTHERN EDGE OF 700-500MB QG-
FORCING...AND UNDER LEFT EXIT REGION OF 90KT JET STREAK RACING UP
FRONT SIDE OF UPPER TROUGH OVER CO/NM. NORTHERN STREAM TROUGH WILL
RACE SOUTHEAST...BRINGING MUCH DRIER AIR INTO CWA...AND THUS...AN
END TO LINGERING -SN OVER NORTHWEST 2/3RDS OF CWA. 25-30KT 850MB
WINDS WILL MIX OVER NORTHWEST SD LEADING TO WINDY CONDITIONS AS IN
CURRENT FORECAST. UPDATE OUT SHORTLY.
&&
.SHORT TERM...(TODAY THROUGH SUNDAY NIGHT)
ISSUED AT 303 AM MST SAT MAR 9 2013
SW CONUS UPPER TROUGH CONTINUES TO PUSH ENE TOWARD THE
REGION AS A NORTHERN STREAM TROUGH DROPS SE INTO THE DAKOTAS. VERY
STRONG WAA RESPONSE ONGOING ACROSS THE CENTRAL PLAINS WILL SPREAD
NORTH INTO SOUTH DAKOTA AND CONTINUE TO SUPPORT RAIN/ZR/AND EVEN A
PERIOD OF TS CHANCES THIS MORNING GIVEN STEEP MID LEVEL LAPSE RATES
AND A CONDITIONALLY UNSTABLE LAYER ALOFT. WAA WILL EVENTUALLY
SUPPORT THE DEVELOPMENT OF A PRONOUNCED DEFORMATION ZONE ACROSS
SCENTRAL SD...WITH VIGOROUS DEEP LAYER ASCENT AS THE NORTHERN STREAM
TROUGH DROPS SOUTH AND SUPPORTS DEEP LAYER CAA. A PERIOD OF HEAVY
SNOW CAN BE EXPECTED IN THE DEFORMATION BAND...WITH HIGH LIQUID
WATER CONTENT AND LOW RATIO. THE LOCATION OF THIS SNOW BAND REMAINS
SEMI-ELUSIVE GIVEN THE PRESENCE OF A STRONG WARM NOSE...AND FORECAST
MODELS HAVE WAVERED PER ITS PLACEMENT. HOWEVER...LATEST GUIDANCE
/ESP FROM THE NAM/ HAVE HONED THE LOCATION TO EASTERN TODD/MELLETTE
AND MUCH OF TRIPP COUNTY. OTHERWISE...THE REMAINDER OF THE FA LOOKS
TO BE FAIRLY DRY SAVE PERHAPS A LITTLE LIGHT SNOW OVER THE NORTHERN
HILLS WHICH LOOKS IFFY AT THIS POINT GIVEN A SHARPLY DRYING BL.
SUBSIDING FLOW WILL PREVAIL ON SUNDAY...WITH DEEP LAYER RIDGING AND
DRY CONDITIONS.
ROBUST WAA RESPONSE WILL PUSH NORTH IN SCENTRAL SD THIS
MORNING...SUPPORTING RAIN/FREEZING RAIN/AND SNOW. RAIN AND FREEZING
RAIN IS EXPECTED TO LAST THROUGH MID MORNING OVER PORTIONS OF
MELLETTE/TODD/AND TRIPP COUNTIES WHERE SOME LIGHT ICING UP TO ONE
TENTH OF A INCH WILL BE POSSIBLE UNTIL ALL PRECIP TRANSITIONS TO
SNOW. MAIN LOBE OF DEEP LAYER ASCENT WILL SPREAD INTO SCENTRAL SD
MID TO LATE MORNING...WITH A STRENGTHENING LL DEFORMATION ZONE.
STRONG LIFT CENTERED IN THE SNOW GROWTH ZONE WILL SUPPORT A VERY
INTENSE BAND OF HEAVY SNOW FOR 3-6 HOURS. HEAVY SNOWFALL RATES ARE
EXPECTED WITH LOCATIONS IN THE BAND EXPECTED TO SEE 3-5 INCHES.
LOCALLY HIGHER AMOUNTS WILL BE POSSIBLE BEFORE SNOW TAPERS OFF THIS
EVENING. A SHARP CUT OFF IN PRECIP IS EXPECTED...SUPPORTING MAINLY
DRY CONDITIONS ACROSS THE NW 1/2-2/3. HAVE DROPPED THE WINTER WEATHER
ADV FOR THE TWO NW COUNTIES...GIVEN LACK OF SIG PRECIP. STRONG
PRESSURE RISES WILL ENSUE IN A CAA REGIME SUPPORTING GUSTY NW
WINDS. STRONGEST WINDS WILL BE IN THE LEE OF THE BH AND ADJACENT
PLAINS GIVEN FLOW ENHANCEMENT AROUND THE BH. SUSTAINED WINDS OF 25 TO
30 MPH WITH GUSTS TO AROUND 50 MPH ARE EXPECTED. HAVE ISSUED A WIND
ADV FOR THIS. 15 TO 30 MPH WINDS WILL SPREAD INTO SCNTRL SD THIS
AFTERNOON AND EVENING AND MAY SUPPORT AREAS OF BLOWING SNOW
DEPENDING ON BL TEMPS. MANY FORECAST SOLUTIONS OFFER TEMPS IN LOWER
30S BY AFTERNOON WHICH COULD HAMPER SNOW LIFTING POTENTIAL THERE.
ADJUSTED POPS TO FIT ABOVE CONCERNS...WITH SOME ADJUSTMENT TO TEMPS.
SUNDAY...FAIRLY QUIET WEATHER TO PREVAIL WITH A PERIOD OF SHORTWAVE
RIDGING. WAA EXPECTED TO INFLUENCE TEMPS ACROSS THE WESTERN HALF OF
THE FA...WITH EASTERN AREAS LIKELY REMAINING UNDER A SUBSIDENCE
INVERSION AND CONTINUED NORTHERLY FLOW. SNOW COVER WILL ALSO
INFLUENCE TEMPS OVER SCENTRAL AREAS. LOWS WILL BE TRICKY SUNDAY
NIGHT OVER THE SNOW PACK...WHERE SIG T DROP OFFS ARE POSSIBLE GIVEN
CLEAR SKIES AND LIGHT WINDS.
.LONG TERM...(MONDAY THROUGH FRIDAY)
ISSUED AT 303 AM MST SAT MAR 9 2013
RIDGE BUILDS OVER THE WESTERN CONUS...WITH AXIS SLOWLY SHIFTING
TOWARDS THE PLAINS THROUGH THE EXTENDED. THIS WILL BRING MILD TEMPS
THROUGH MID-WEEK...WITH WARMER TEMPS EXPECTED FOR THE LAST PART OF
THE WORK WEEK. OCCASIONAL WEAK DISTURBANCES MOVING THROUGH MAY BRING
A FEW LIGHT SHOWERS THROUGH MID-WEEK...WITH GENERALLY DRY CONDITIONS
FOR THE END OF THE WORK WEEK.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SUNDAY MORNING)
ISSUED AT 303 AM MST SAT MAR 9 2013
WIDESPREAD IFR CONDITIONS WILL CONT THRU WRN SD INTO PTNS OF NERN WY
THROUGH MUCH OF THE DAY. OVER S CNTRL SD FZRA/SN EXPECTED THIS
MORN...WITH A TRANSITION TO ALL SN THIS AFTERNOON. ELSEWHERE...
PERIODS OF SNOW ARE EXPECTED WITH THE GREATEST CHANCES TOWARDS THE
NEBRASKA BORDER. PRECIP WILL DIMINISH FROM NORTHWEST TO SOUTHEAST
LATER THIS AFTERNOON INTO THIS EVE WITH CIGS/VIS IMPROVING.
&&
.UNR WATCHES/WARNINGS/ADVISORIES...
SD...WINTER WEATHER ADVISORY UNTIL 5 PM MST /6 PM CST/ THIS AFTERNOON
FOR SDZ044-046-047-049.
WIND ADVISORY UNTIL 7 PM MST THIS EVENING FOR SDZ026-030-031-
072>074.
WY...NONE.
&&
$$
UPDATE...HELGESON
SHORT TERM...JC
LONG TERM...77
AVIATION...77
AREA FORECAST DISCUSSION
NWS GOODLAND KS
147 PM MST SAT MAR 9 2013
.SHORT TERM...(TODAY THROUGH SUNDAY)
ISSUED AT 145 PM MST SAT MAR 9 2013
LATEST WV IMAGERY AND RUC H5 ANALYSIS SHOW LARGE SCALE TROUGH
EXTENDING FROM CENTRAL CANADA AND ACROSS THE INTERMOUNTAIN
WEST...WITH A CLOSED CENTER OVER NORTHERN NEW MEXICO. H7 TROUGH AXIS
ALONG KS/CO BORDER. SATELLITE IMAGERY AND REGIONAL RADAR SHOWS
DEFORMATION BAND JUST WEST OF H7 TROUGH AXIS ACROSS EASTERN EASTERN
COLORADO EXTENDING NORTH THROUGH THE NEBRASKA PANHANDLE AND INTO
SOUTH DAKOTA. DRY SLOT DEVELOPED AHEAD OF THE TROUGH EARLY THIS
MORNING AND IS CURRENTLY IN PLACE OVER ALL BUT THE FAR WESTERN
EXTENT OF CWA.
AXIS OF MODEST INSTABILITY HAS DEVELOPED JUST EAST OF OUR CWA IN
RESPONSE TO VERY MOIST BL AND STRONG WAA AHEAD OF SURFACE LOW.
THUNDERSTORMS HAVE DEVELOPED ACROSS NORTH CENTRAL KANSAS AND CENTRAL
NEBRASKA. SURFACE TD HAVE ALREADY BEEN DECREASING AT NORTON AND HILL
CITY...SO THE THREAT FOR THUNDERSTORMS MAY BE DECREASING FOR OUR
AREA. WE COULD STILL SEE A WINDOW FOR THUNDERSTORMS TO DEVELOP IN
OUR EASTERN CWA THIS AFTERNOON BEFORE THE COLD FRONT PUSHES
EAST...SO I KEPT A SLIGHT CHANCE OF THUNDERSTORMS GOING THROUGH 00Z
FOR EASTERN LOCATIONS.
THERE ARE DIFFERENCES REGARDING THE EVOLUTION OF SNOW BAND TONIGHT
THOUGH MODEL CONSENSUS STILL SHOWS THIS BAND MOVING EAST AND
PRODUCING HEAVY SNOW ACCUMULATIONS AROUND 7 INCHES ACROSS OUR
NORTHWEST...AND LESSER AMOUNTS SOUTH AND EAST. THERE SHOULD BE A
QUICK RAIN/SNOW CHANGE OVER IN THE WEST...WITH CHANGEOVER THIS
EVENING IN THE EAST WHERE WARMER TEMPERATURES ARE STILL IN PLACE.
UPSTREAM OBS ALREADY SHOW LIGHT SNOW IN YUMA COUNTY...IN LINE WITH
CURRENT FORECAST TIMING. THE DEFORMATION BAND SHOULD WEAKEN AFTER
06Z AS LARGE SCALE FORCING BEGINS TO PULL EAST...AND DRY AIR ACROSS
THE NORTHERN ROCKIES PUSHES SOUTH AND EAST. IT IS WORTH NOTING THAT
THE LATEST GFS AND ECMWF ACTUALLY INDICATE THAT THIS SNOW BAND WILL
HOLD TOGETHER IF NOT INTENSIFY AFTER 06Z WITH HIGHER AMOUNTS BY AS
MUCH AS 2-3 INCHES MORE THAN CURRENT FORECAST. WITH RUC/NAM/GFS ALL
SHOWING INSTABILITY WITHIN 700-500MB LAYER WITH THIS BAND...THERE
MAY BE A CONNECTIVE COMPONENT THAT COULD SUPPORT LOCALLY HIGHER
AMOUNTS IN LINE WITH THESE HIGHER TOTALS...HOWEVER IT IS HARD TO
GAUGE WHERE THIS WILL SET UP AND HOW WIDESPREAD IT WILL BE. I ALSO
THINK THE WINDOW FOR CONVECTIVE BANDING WILL BE DURING THE EVENING
RATHER THAN AFTER 06Z...SINCE MODELS ARE GENERALLY INDICATING A
DECREASE IN INSTABILITY AS DRY/STABLE AIR MOVES IN FROM THE NW
BEHIND THIS BAND. WARM GROUND TEMPERATURES COULD LEAD TO ADDITIONAL
MELTING WHICH COULD EAT INTO OUR SNOW AMOUNTS EARLY ON...HOWEVER AS
SNOWFALL INTENSIFIES AND TEMPERATURES BEGIN TO DROP WE SHOULD START
TO OVERCOME THIS.
MODELS ARE STILL SHOWING STRONG H85 JET DEVELOPING BEHIND FRONT LATE
THIS AFTERNOON AND EVENING. NAM WOULD INDICATE A SMALLER WINDOW FOR
THE STRONGEST WINDS UP NORTH...HOWEVER IT STILL SHOWS POTENTIAL FOR
GUSTS AROUND 35MPH THROUGH THE NIGHT UP NORTH...AND GUSTS 40-50MPH
ACROSS THE SOUTH THROUGH MOST OF THE NIGHT. THIS SHOULD SUPPORT
WIDESPREAD BLOWING SNOW WITH WHITE OUT CONDITIONS ACROSS THE AREA.
I DECIDED AGAINST MAKING ANY WHOLESALE CHANGES TO FORECAST OR
BLIZZARD WARNING TONIGHT WITH ONLY ADJUSTMENTS TO DETAILS AND
RAIN/SNOW TIMING BASED ON CURRENT TRENDS. WE MAY NEED TO MAKE
FURTHER ADJUSTMENTS AS THIS BAND STARTS MOVING EAST AND WE GET A
BETTER HANDLE ON HOW QUICKLY IT WEAKENS LATE TONIGHT.
.LONG TERM...(SUNDAY NIGHT THROUGH FRIDAY)
ISSUED AT 145 PM MST SAT MAR 9 2013
THE STORM THAT IS AFFECTING OUR FORECAST AREA THIS WEEKEND WILL
BE HEADING OUT OF THE PLAINS REGION AND WILL BE MOVING TOWARDS THE
GREAT LAKES AND MISSISSIPPI VALLEY REGIONS ON SUNDAY NIGHT AND
MONDAY. A COUPLE OF WEAK SHORT WAVE TROUGHS WILL MOVE ACROSS THE
CENTRAL HIGH PLAINS REGION IN THE UPPER NORTHWEST FLOW MONDAY
MORNING AND DURING THE DAY ON WEDNESDAY...OTHERWISE THE RIDGE THAT
MOVES INTO THE WESTERN UNITED STATES DURING THE FIRST PART OF NEXT
WEEK BECOMES A BROAD RIDGE OVER THE WESTERN UNITED
STATES...EXTENDING FROM THE INTERMOUNTAIN REGION TO THE PLAINS
STATES BY THE END OF THE WEEK.
THE RIDGE APPEARS TO WEAKEN SOMEWHAT BY NEXT WEEKEND AS ANOTHER
TROUGH APPROACHES THE WEST COAST...BUT THERE IS CURRENTLY A LARGE
AMOUNT OF DISAGREEMENT IN THE MODELS OVER THE WEST COAST DURING
THAT TIME PERIOD. BY NEXT SATURDAY...THE CENTRAL HIGH PLAINS
REGION SEEMS TO STILL BE UNDER A WEAK RIDGE WITH A TRANSITION IN
THE PATTERN UNDERWAY OVER THE WESTERN UNITED STATES.
WITH UNIDIRECTIONAL NORTH TO NORTHWEST FLOW THROUGH THE ATMOSPHERE
SUNDAY NIGHT AND MONDAY...BREEZY CONDITIONS COULD PERSIST THROUGH
THAT TIME ACROSS THE FORECAST AREA. OTHER THAN SOME WIND EARLY IN
THE LONG TERM PERIOD...THE CONDITIONS DURING THE LONG TERM PORTION OF
THE FORECAST APPEAR TO BE BENIGN WITH NO PRECIPITATION EXPECTED
AND GOOD AGREEMENT BETWEEN MODEL SOLUTIONS. TEMPERATURES WILL
CONTINUE TO RISE EACH DAY WITH HIGH TEMPERATURES INCREASING FROM
THE UPPER 40S AND LOWER 50S ON MONDAY TO THE UPPER 60S AND LOWER
70S BY FRIDAY. LOW TEMPERATURES WILL INCREASE FROM THE UPPER TEENS
ON SUNDAY NIGHT TO THE UPPER 30S BY FRIDAY NIGHT.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON)
ISSUED AT 1035 AM MST SAT MAR 9 2013
EARLY IN THE TAF PERIOD IFR CIGS ASSOCIATED WITH STRATUS DECK WILL
LINGER AT BOTH KGLD/KMCK...WITH LIGHT FOG AND MVFR VIS LINGERING.
MAIN BAND OF RAIN/SNOW OVER EASTERN COLORADO IS EXPECTED TO
OVERSPREAD BOTH TERMINALS THIS AFTERNOON WITH COVERAGE INCREASING
LATE THIS AFTERNOON THROUGH THE EVENING. SHOULD SEE A GRADUAL
REDUCTION IN AVIATION CONDITIONS WITH LIFR ASSOCIATED WITH SNOW
AND BLOWING SNOW THIS EVENING THROUGH EARLY SUNDAY MORNING. BASED
ON CURRENT TIMING I EXPECT THE MAIN BAND SHOULD WEAKEN AND SHIFT TO
THE EAST WITH CONDITIONS IMPROVING AT KGLD AFTER 09Z AND THEN
AROUND 10Z AT KMCK. VFR CIG/VIS IS EXPECTED BY MID MORNING AT BOTH
TERMINALS WITH DRY/STABLE AIR MOVING IN ON BACK SIDE OF UPPER LOW.
IT IS WORTH NOTING THAT THERE COULD BE A FEW THUNDERSTORM DEVELOP
THIS AFTERNOON AHEAD OF COLD FRONT...HOWEVER THIS SHOULD BE EAST
OF BOTH TERMINALS...SO I LEFT MENTION OF OUT TAFS.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...BLIZZARD WARNING UNTIL 9 AM MDT /10 AM CDT/ SUNDAY FOR KSZ001-
013-027.
BLIZZARD WARNING FROM 5 PM MST /6 PM CST/ THIS AFTERNOON TO 9 AM
MDT /10 AM CDT/ SUNDAY FOR KSZ002>004-014>016-028-029-041-
042.
CO...BLIZZARD WARNING UNTIL 9 AM MDT SUNDAY FOR COZ090>092.
NE...BLIZZARD WARNING UNTIL 9 AM MDT /10 AM CDT/ SUNDAY FOR NEZ079-
080.
BLIZZARD WARNING FROM 6 PM CST THIS EVENING TO 10 AM CDT SUNDAY
FOR NEZ081.
&&
$$
SHORT TERM...DR
FS LONG TERM...LOCKHART
AVIATION...DR
AREA FORECAST DISCUSSION...UPDATED
NWS NORTH PLATTE NE
1233 PM CST SAT MAR 9 2013
.UPDATE...
ISSUED AT 1232 PM CST SAT MAR 9 2013
EARLY AFTERNOON UPDATE...SNOW REPORTS OF 3-6 INCHES ARE COMING IN
FOR SEVERAL LOCATIONS ACROSS NORTH WESTERN/CENTRAL NEBRASKA...THUS THE
MAIN DEFORMATION BAND IS BEHAVING AS IT SHOULD. OTHERWISE THE ONLY
SIGNIFICANT CHANGE TO THE ONGOING FORECAST WAS TO INCLUDE THE
MENTION OF THUNDER ACROSS FAR SOUTHEASTERN PORTIONS OF THE CWA.
STORMS HAVE ALREADY DEVELOPED...WITH CG NOTED SOUTH OF MASON CITY
OVER THE PAST HALF HOUR.
UPDATE ISSUED AT 1021 CST SAT MAR 9 2013
OVERALL IDEA OF THE FORECAST REMAINS ON TRACK WITH ONLY MINOR
REVISIONS TO FRESHEN UP WIND SPEEDS...TIMING OF THE SNOW
CHANGEOVER...AND FREEZING RAIN AMOUNTS. PHONE CALLS IN AND AROUND
KVTN THIS MORNING SUGGESTED ABOUT A TENTH OF AN INCH OF ICE OR
LESS ACCUMULATION...THUS WILL TREND DOWN THE QUARTER OF AN INCH WE
HAD GOING FOR THE CENTRAL SAND HILLS...WITH WORDING OF MINOR
ICE ACCUMULATIONS. OTHERWISE ONCE THE CHANGE OVER TO SNOW
OCCURS...SNOW RATES OF AN INCH PER HOUR HAVE BEEN NOTED UNDER THE
HEAVIEST OF BANDS. 12Z NAM APPEARS REASONABLE AT THIS
JUNCTURE...THUS TRENDED IN THAT DIRECTION. THE NARROW BAND OF QPF
WILL CONTINUE THROUGH MID AFTERNOON ACROSS NORTHWEST NEBRASKA
ALONG A STRONG BAND OF H7 FRONTOGENESIS AND WITH AID FROM THE LFQ
OF A 90KT JET. SNOW ACCUMULATIONS OF 6 INCHES OR GREATER STILL
APPEARS LIKELY ACROSS NORTHWEST NEBRASKA. BUT LATER TODAY...SNOW
WILL BEGIN TO TAPER OFF BY LATE AFTERNOON AS THE NORTHERN STREAM
RACES SOUTHEAST ACROSS THE NORTHERN PLAINS AND ALLOWS FOR THE
INTRUSION OF DRIER AIR INTO THE NORTHERN REACHES OF THE CWA.
HOWEVER ALL NEAR TERM SOLUTIONS DO INDICATE THE FORMATION OF A
SECOND AREA OF DEFORMATION ACROSS FAR SOUTHEASTERN PORTIONS OF THE
FORECAST AREA...ALIGNED NORTHEAST TO SOUTHWEST WITH THE EASTWARD
ADVANCING MID LEVEL FRONTOGENETIC FORCING...FORECAST FOR THIS
SECOND BAND APPEARS ON TRACK AT THIS TIME...WILL REVISIT EXPECTED
SNOW AMOUNTS AS ADDITIONAL GUIDANCE COMES IN THIS MORNING.
UPDATE ISSUED AT 700 AM CST SAT MAR 9 2013
NO NEW DATA WAS AVAILABLE FOR THE QPF FORECAST BUT INDICATIONS ARE
THE RAP13 IS VERIFYING ACROSS NRN NEB WITH OVER 1/2 INCH OF ICE AT
THE KVTN ASOS. AFTER SLOWING THE EASTERN PROGRESSION OF THE RAIN
CHANGE LINE USING THE RUC...NORTH WINDS HAVE INCREASED AND NOW THE
RAIN CHANGE LINE IS ROUGHLY FROM CHAPPELL TO THEDFORD TO AINSWORTH.
SO THE NAM MAY BE VERIFYING BETTER AND IT WAS USED IN THE NEW
FORECAST.
A NEW WIND FORECAST USING NAM...GEM...MET AND MAV GUIDANCE
PRODUCED GUSTS TO 50 MPH THIS AFTERNOON AND THIS EVENING WHICH IS
CONSISTENT WITH THE 60KT BARRIER JET FCST BY BOTH MODELS. THIS
STRUCTURE IS FCST TO SET UP ACROSS THE ERN PANHANDLE THIS MORNING
AND MOVE SLOWLY EAST THIS AFTN AND TONIGHT ACTING AS A FOCUS FOR
SNOW AND STRONG WINDS.
THERE IS NO CHANGE TO THE DYNAMICS. STRONG FRONTOGENESIS HANGS
UP ACROSS THE NORTHWEST TODAY AND DECAYS WHILE A NEW STRUCTURE
DEVELOPS FARTHER EAST THIS EVENING. THE RAP HAS COME IN LINE WITH
THE NAM AND ECM DEVELOPING THE NEW SNOW EAST OF THE FCST AREA
WHILE THE 06Z GFS HANGS IT UP ACROSS NCNTL AND SWRN NEB...VERY
TROUBLING. GIVEN THE VERY STRONG WINDS DEVELOPING...EVEN AN 1/2
INCH PER HOUR SNOWFALL RATE COULD PRODUCE BLIZZARD CONDITIONS.
THE SNOW SHOULD GRADUALLY END OVERNIGHT AND SUNDAY MORNING WEST TO
EAST WITH CLEARING SKIES TO FOLLOW. WINDY CONDITIONS CONTINUE
SUNDAY MORNING IN THE EAST.
UPDATE ISSUED AT 527 AM CST SAT MAR 9 2013
THE RAP13 MODEL SHOWS A SLOWER TRANSITION TO SNOW THAN THE NAM. IN
FACT THE RAP CARRIES A BROAD AREA OF FREEZING RAIN AHEAD OF THE
CHANGEOVER TO SNOW. THIS IS WELL SUPPORTED IN THE MODEL TEMPERATURE
FIELDS. SO A NEW FORECAST IS OUT WHICH HEIGHTENS THE THREAT OF
FREEZING RAIN.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 345 AM CST SAT MAR 9 2013
TWO ROUNDS OF THOUGHT WITH THE STORM. ONE IS FOR A STRONG FGEN
FORCED BAND OF SNOW DEVELOPING ACROSS NORTHWEST NEBRASKA TODAY
WHICH MOST SOLNS AGREE ON TO VARYING DEGREES. THE SECOND IS FOR
ANOTHER STRONG BAND OF SNOW TO DEVELOP ACROSS SOUTH CENTRAL
NEBRASKA TONIGHT AS THE FIRST BAND DECAYS. THE GEM REGIONAL AND
GFS ARE VERY FAR NORTHWEST WITH THIS BAND SIGNALING A WINTER
STORM FOR NCNTL NEB WHILE THE NAM AND ECM ARE SAFELY EAST OF THE
FCST AREA. A BLEND OF NAM...GEM AND ECM WERE USED FOR THE LATEST
FCST WHICH PROVIDES A WINTER STORM ACROSS THE NORTHWEST AND A
WINTER WEATHER ADVISORY ELSEWHERE.
HOWEVER THE NAM AND RAP SHOW A VERY STRONG BARRIER JET DEVELOPING
THIS EVENING STRETCHING NORTH-SOUTH ALONG AND WEST OF HIGHWAY 83
WHICH COULD EASILY SUPPORT A WINTER STORM IF THE FRONTOGENESIS
WAS APPROPRIATELY JUXTAPOSED. THIS IS NOT THE CASE AS THE NAM
SHOWS THE FGEN AND HEAVY QPF MOSTLY EAST OF THE FCST AREA. THE
RAP MEANWHILE NOSES THE PV1.5 ANOMALY INTO SRN NEB AT 02Z AND
DEVELOPS SOME HEAVY SNOW ACROSS SWRN NEB. THIS IS A CONCERN WHICH
WILL BE CLOSELY MONITORED.
THE STRONG BARRIER JET WILL EASILY SUPPORT 30 MPH WINDS WITH
GUSTS TO 45 MPH. IN FACT THE NAM AND RAP SHOW GUSTS TO 60 MPH AT
00Z-03Z...THE HEIGHT OF THE STORM ACROSS SWRN AND NCNTL NEB.
SO EVERYONE OUTSIDE OF THE WINTER STORM WARNING HAS BEEN PLACED
IN A WINTER WEATHER ADVISORY FOR 3 TO 5 INCHES OF SNOW AND 30 TO
45 MPH WINDS.
.LONG TERM...(SUNDAY THROUGH FRIDAY)
ISSUED AT 345 AM CST SAT MAR 9 2013
MAJOR SPRING/WINTER STORM WILL BE EXITING SUNDAY MORNING WITH
SOME LINGERING LIGHT SNOW ACROSS THE FAR EASTERN COUNTIES. WINDS
WILL CONTINUE TO BE GUSTY...AND WILL HIGHLIGHT PATCHY BLOWING
SNOW WHERE FALLING SNOW IS EXPECTED. PENDING TOTAL SNOW AND HOW
FLUFFY IT IS...MAY NEED TO CONTINUE BLOWING SNOW FURTHER WEST
EARLY SUNDAY. STILL QUESTIONING HOW FAR WEST THE HEAVY BAND OF
SNOW OVER CENTRAL NEB WILL BE.
SUNDAY HIGHS...WITH COLD HIGH PRESSURE BUILDING SOUTH ACROSS THE
NORTHERN PLAINS AND MUCH IF NOT ALL OF THE AREA EXPECTED TO SEE A
SNOW COVER...SHOULD HOLD CLOSE TO 30 DEGREES. ALTHOUGH THE SUN
WILL SPREADING FROM WEST TO EAST...WHICH SHOULD HELP TO START TO
MELT ROADWAYS.
SUNDAY NIGHT WITH AN ELONGATED HIGH ACROSS THE WESTERN
PLAINS...LIGHT WINDS AND MOSTLY CLEAR SKIES ALONG WITH SNOW
PACK...TEMPS SHOULD TANK. WIDESPREAD TEENS...WHICH MAY BE
CONSERVATIVE.
MONDAY INTO MID WEEK RIDGE BUILDS ACROSS THE WEST...WITH A TROUGH
TO PUSH ALONG THE NORTHERN STREAM...ACROSS SOUTHERN CANADA AND
THE GREAT LAKES. WEAK DISTURBANCE TO MOVE ALONG THE NW FLOW
ACROSS THE AREA...HOWEVER MOISTURE LIMITED AND DOUBT ANYTHING
WILL REACH THE GROUND AS TIMING IS A LITTLE SLOWER WITH PASSAGE
MORE OF A DAYTIME AND THE HEAT OF THE DAY SHOULD BE ENOUGH TO
KEEP ANYTHING FROM HITTING THE GROUND. ALSO EARLY IN THE WEEK AS
THE SNOW MELTS WILL NEED TO MONITOR FOR OVERNIGHT/MORNING FOG.
RIDGE EXPANDS AS THE WEEK CONTINUES...WITH STRONG WAA ALOFT WITH
THE WESTERN PART OF THE CWA SEEING DOUBLE DIGIT 850 TEMPS.
QUESTION WILL BE HOW LONG CAN THE SNOW REMAIN AND DAMPEN TEMPS.
GUIDANCE PUSHES HIGHS INTO THE 50S AND 60S FOR WEDNESDAY AND
THURSDAY. AS IS TYPICAL WITH MANY MARCH SNOW STORMS...EXPECT THIS
SNOW NOT TO STAY LONG. ALTHOUGH WEST WINDS ON THE LIGHT
SIDE...LESS THAN 15 MPH...SHOULD BE ENOUGH TO HELP MIX WITH THE
DOWNSLOPE COMPONENT AND HAVE FOLLOWED CLOSER TO GUIDANCE FOR THE
LATER HALF OF THE WEEK.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON)
ISSUED AT 1153 AM CST SAT MAR 9 2013
EXPECTING WIDESPREAD IFR/LIFR CONDITIONS TO CONTINUE THROUGH 03Z
TONIGHT...WITH SNOW...BLOWING SNOW...FREEZING
RAIN...THUNDERSTORMS...AND RAIN ALL POSSIBLE FOR AREA TERMINALS.
KVTN...KTIF...KANW AND KOGA HAVE SWITCHED OVER TO SNOW...WITH
PERIODIC VISIBILITY REDUCTIONS TO 1/2SM. AT KLBF...KIML...KONL &
KBBW...ONLY LIGHT RAIN HAS THUS FAR BEEN OBSERVED...HOWEVER CONDITIONS
ARE EXPECTED TO DETERIORATE THIS AFTERNOON AS COLD AIR UNDERCUTS THE
FALLING PRECIPITATION. A BRIEF PERIOD OF FREEZING RAIN MAY BE
POSSIBLE WHERE THE CHANGE OVER TO SNOW HAS NOT OCCURRED...INCLUDING
THE KLBF TERMINAL. IN ADDITION...STRONG NORTHERLY WIND GUSTS IN
EXCESS OF 30KTS WILL CONTINUE THROUGH THE TAF FORECAST
PERIOD...WHICH WOULD LOWER VISIBILITY FURTHER IF SNOW IS FALLING.
LATE THIS EVENING...IMPROVEMENT TO MVFR/VFR SHOULD COMMENCE FROM
NORTHWEST TO SOUTHEAST.
&&
.LBF WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY UNTIL 7 AM CDT /6 AM MDT/ SUNDAY FOR
NEZ006>010-025>029-036>038-057>059-069>071.
WINTER STORM WARNING UNTIL 7 AM CDT /6 AM MDT/ SUNDAY FOR NEZ004-
005-022>024-035-056-094.
&&
$$
UPDATE...JACOBS
SHORT TERM...CDC
LONG TERM...MASEK
AVIATION...JACOBS
AREA FORECAST DISCUSSION
NWS NORTH PLATTE NE
1154 AM CST SAT MAR 9 2013
.UPDATE...
ISSUED AT 1021 CST SAT MAR 9 2013
OVERALL IDEA OF THE FORECAST REMAINS ON TRACK WITH ONLY MINOR
REVISIONS TO FRESHEN UP WIND SPEEDS...TIMING OF THE SNOW
CHANGEOVER...AND FREEZING RAIN AMOUNTS. PHONE CALLS IN AND AROUND
KVTN THIS MORNING SUGGESTED ABOUT A TENTH OF AN INCH OF ICE OR
LESS ACCUMULATION...THUS WILL TREND DOWN THE QUARTER OF AN INCH WE
HAD GOING FOR THE CENTRAL SAND HILLS...WITH WORDING OF MINOR
ICE ACCUMULATIONS. OTHERWISE ONCE THE CHANGE OVER TO SNOW
OCCURS...SNOW RATES OF AN INCH PER HOUR HAVE BEEN NOTED UNDER THE
HEAVIEST OF BANDS. 12Z NAM APPEARS REASONABLE AT THIS
JUNCTURE...THUS TRENDED IN THAT DIRECTION. THE NARROW BAND OF QPF
WILL CONTINUE THROUGH MID AFTERNOON ACROSS NORTHWEST NEBRASKA
ALONG A STRONG BAND OF H7 FRONTOGENESIS AND WITH AID FROM THE LFQ
OF A 90KT JET. SNOW ACCUMULATIONS OF 6 INCHES OR GREATER STILL
APPEARS LIKELY ACROSS NORTHWEST NEBRASKA. BUT LATER TODAY...SNOW
WILL BEGIN TO TAPER OFF BY LATE AFTERNOON AS THE NORTHERN STREAM
RACES SOUTHEAST ACROSS THE NORTHERN PLAINS AND ALLOWS FOR THE
INTRUSION OF DRIER AIR INTO THE NORTHERN REACHES OF THE CWA.
HOWEVER ALL NEAR TERM SOLUTIONS DO INDICATE THE FORMATION OF A
SECOND AREA OF DEFORMATION ACROSS FAR SOUTHEASTERN PORTIONS OF THE
FORECAST AREA...ALIGNED NORTHEAST TO SOUTHWEST WITH THE EASTWARD
ADVANCING MID LEVEL FRONTOGENETIC FORCING...FORECAST FOR THIS
SECOND BAND APPEARS ON TRACK AT THIS TIME...WILL REVISIT EXPECTED
SNOW AMOUNTS AS ADDITIONAL GUIDANCE COMES IN THIS MORNING.
UPDATE ISSUED AT 700 AM CST SAT MAR 9 2013
NO NEW DATA WAS AVAILABLE FOR THE QPF FORECAST BUT INDICATIONS ARE
THE RAP13 IS VERIFYING ACROSS NRN NEB WITH OVER 1/2 INCH OF ICE AT
THE KVTN ASOS. AFTER SLOWING THE EASTERN PROGRESSION OF THE RAIN
CHANGE LINE USING THE RUC...NORTH WINDS HAVE INCREASED AND NOW THE
RAIN CHANGE LINE IS ROUGHLY FROM CHAPPELL TO THEDFORD TO AINSWORTH.
SO THE NAM MAY BE VERIFYING BETTER AND IT WAS USED IN THE NEW
FORECAST.
A NEW WIND FORECAST USING NAM...GEM...MET AND MAV GUIDANCE
PRODUCED GUSTS TO 50 MPH THIS AFTERNOON AND THIS EVENING WHICH IS
CONSISTENT WITH THE 60KT BARRIER JET FCST BY BOTH MODELS. THIS
STRUCTURE IS FCST TO SET UP ACROSS THE ERN PANHANDLE THIS MORNING
AND MOVE SLOWLY EAST THIS AFTN AND TONIGHT ACTING AS A FOCUS FOR
SNOW AND STRONG WINDS.
THERE IS NO CHANGE TO THE DYNAMICS. STRONG FRONTOGENESIS HANGS
UP ACROSS THE NORTHWEST TODAY AND DECAYS WHILE A NEW STRUCTURE
DEVELOPS FARTHER EAST THIS EVENING. THE RAP HAS COME IN LINE WITH
THE NAM AND ECM DEVELOPING THE NEW SNOW EAST OF THE FCST AREA
WHILE THE 06Z GFS HANGS IT UP ACROSS NCNTL AND SWRN NEB...VERY
TROUBLING. GIVEN THE VERY STRONG WINDS DEVELOPING...EVEN AN 1/2
INCH PER HOUR SNOWFALL RATE COULD PRODUCE BLIZZARD CONDITIONS.
THE SNOW SHOULD GRADUALLY END OVERNIGHT AND SUNDAY MORNING WEST TO
EAST WITH CLEARING SKIES TO FOLLOW. WINDY CONDITIONS CONTINUE
SUNDAY MORNING IN THE EAST.
UPDATE ISSUED AT 527 AM CST SAT MAR 9 2013
THE RAP13 MODEL SHOWS A SLOWER TRANSITION TO SNOW THAN THE NAM. IN
FACT THE RAP CARRIES A BROAD AREA OF FREEZING RAIN AHEAD OF THE
CHANGEOVER TO SNOW. THIS IS WELL SUPPORTED IN THE MODEL TEMPERATURE
FIELDS. SO A NEW FORECAST IS OUT WHICH HEIGHTENS THE THREAT OF
FREEZING RAIN.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 345 AM CST SAT MAR 9 2013
TWO ROUNDS OF THOUGHT WITH THE STORM. ONE IS FOR A STRONG FGEN
FORCED BAND OF SNOW DEVELOPING ACROSS NORTHWEST NEBRASKA TODAY
WHICH MOST SOLNS AGREE ON TO VARYING DEGREES. THE SECOND IS FOR
ANOTHER STRONG BAND OF SNOW TO DEVELOP ACROSS SOUTH CENTRAL
NEBRASKA TONIGHT AS THE FIRST BAND DECAYS. THE GEM REGIONAL AND
GFS ARE VERY FAR NORTHWEST WITH THIS BAND SIGNALING A WINTER
STORM FOR NCNTL NEB WHILE THE NAM AND ECM ARE SAFELY EAST OF THE
FCST AREA. A BLEND OF NAM...GEM AND ECM WERE USED FOR THE LATEST
FCST WHICH PROVIDES A WINTER STORM ACROSS THE NORTHWEST AND A
WINTER WEATHER ADVISORY ELSEWHERE.
HOWEVER THE NAM AND RAP SHOW A VERY STRONG BARRIER JET DEVELOPING
THIS EVENING STRETCHING NORTH-SOUTH ALONG AND WEST OF HIGHWAY 83
WHICH COULD EASILY SUPPORT A WINTER STORM IF THE FRONTOGENESIS
WAS APPROPRIATELY JUXTAPOSED. THIS IS NOT THE CASE AS THE NAM
SHOWS THE FGEN AND HEAVY QPF MOSTLY EAST OF THE FCST AREA. THE
RAP MEANWHILE NOSES THE PV1.5 ANOMALY INTO SRN NEB AT 02Z AND
DEVELOPS SOME HEAVY SNOW ACROSS SWRN NEB. THIS IS A CONCERN WHICH
WILL BE CLOSELY MONITORED.
THE STRONG BARRIER JET WILL EASILY SUPPORT 30 MPH WINDS WITH
GUSTS TO 45 MPH. IN FACT THE NAM AND RAP SHOW GUSTS TO 60 MPH AT
00Z-03Z...THE HEIGHT OF THE STORM ACROSS SWRN AND NCNTL NEB.
SO EVERYONE OUTSIDE OF THE WINTER STORM WARNING HAS BEEN PLACED
IN A WINTER WEATHER ADVISORY FOR 3 TO 5 INCHES OF SNOW AND 30 TO
45 MPH WINDS.
.LONG TERM...(SUNDAY THROUGH FRIDAY)
ISSUED AT 345 AM CST SAT MAR 9 2013
MAJOR SPRING/WINTER STORM WILL BE EXITING SUNDAY MORNING WITH
SOME LINGERING LIGHT SNOW ACROSS THE FAR EASTERN COUNTIES. WINDS
WILL CONTINUE TO BE GUSTY...AND WILL HIGHLIGHT PATCHY BLOWING
SNOW WHERE FALLING SNOW IS EXPECTED. PENDING TOTAL SNOW AND HOW
FLUFFY IT IS...MAY NEED TO CONTINUE BLOWING SNOW FURTHER WEST
EARLY SUNDAY. STILL QUESTIONING HOW FAR WEST THE HEAVY BAND OF
SNOW OVER CENTRAL NEB WILL BE.
SUNDAY HIGHS...WITH COLD HIGH PRESSURE BUILDING SOUTH ACROSS THE
NORTHERN PLAINS AND MUCH IF NOT ALL OF THE AREA EXPECTED TO SEE A
SNOW COVER...SHOULD HOLD CLOSE TO 30 DEGREES. ALTHOUGH THE SUN
WILL SPREADING FROM WEST TO EAST...WHICH SHOULD HELP TO START TO
MELT ROADWAYS.
SUNDAY NIGHT WITH AN ELONGATED HIGH ACROSS THE WESTERN
PLAINS...LIGHT WINDS AND MOSTLY CLEAR SKIES ALONG WITH SNOW
PACK...TEMPS SHOULD TANK. WIDESPREAD TEENS...WHICH MAY BE
CONSERVATIVE.
MONDAY INTO MID WEEK RIDGE BUILDS ACROSS THE WEST...WITH A TROUGH
TO PUSH ALONG THE NORTHERN STREAM...ACROSS SOUTHERN CANADA AND
THE GREAT LAKES. WEAK DISTURBANCE TO MOVE ALONG THE NW FLOW
ACROSS THE AREA...HOWEVER MOISTURE LIMITED AND DOUBT ANYTHING
WILL REACH THE GROUND AS TIMING IS A LITTLE SLOWER WITH PASSAGE
MORE OF A DAYTIME AND THE HEAT OF THE DAY SHOULD BE ENOUGH TO
KEEP ANYTHING FROM HITTING THE GROUND. ALSO EARLY IN THE WEEK AS
THE SNOW MELTS WILL NEED TO MONITOR FOR OVERNIGHT/MORNING FOG.
RIDGE EXPANDS AS THE WEEK CONTINUES...WITH STRONG WAA ALOFT WITH
THE WESTERN PART OF THE CWA SEEING DOUBLE DIGIT 850 TEMPS.
QUESTION WILL BE HOW LONG CAN THE SNOW REMAIN AND DAMPEN TEMPS.
GUIDANCE PUSHES HIGHS INTO THE 50S AND 60S FOR WEDNESDAY AND
THURSDAY. AS IS TYPICAL WITH MANY MARCH SNOW STORMS...EXPECT THIS
SNOW NOT TO STAY LONG. ALTHOUGH WEST WINDS ON THE LIGHT
SIDE...LESS THAN 15 MPH...SHOULD BE ENOUGH TO HELP MIX WITH THE
DOWNSLOPE COMPONENT AND HAVE FOLLOWED CLOSER TO GUIDANCE FOR THE
LATER HALF OF THE WEEK.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON)
ISSUED AT 1153 AM CST SAT MAR 9 2013
EXPECTING WIDESPREAD IFR/LIFR CONDITIONS TO CONTINUE THROUGH 03Z
TONIGHT...WITH SNOW...BLOWING SNOW...FREEZING
RAIN...THUNDERSTORMS...AND RAIN ALL POSSIBLE FOR AREA TERMINALS.
KVTN...KTIF...KANW AND KOGA HAVE SWITCHED OVER TO SNOW...WITH
PERIODIC VISIBILITY REDUCTIONS TO 1/2SM. AT KLBF...KIML...KONL &
KBBW...ONLY LIGHT RAIN HAS THUS FAR BEEN OBSERVED...HOWEVER CONDITIONS
ARE EXPECTED TO DETERIORATE THIS AFTERNOON AS COLD AIR UNDERCUTS THE
FALLING PRECIPITATION. A BRIEF PERIOD OF FREEZING RAIN MAY BE
POSSIBLE WHERE THE CHANGE OVER TO SNOW HAS NOT OCCURRED...INCLUDING
THE KLBF TERMINAL. IN ADDITION...STRONG NORTHERLY WIND GUSTS IN
EXCESS OF 30KTS WILL CONTINUE THROUGH THE TAF FORECAST
PERIOD...WHICH WOULD LOWER VISIBILITY FURTHER IF SNOW IS FALLING.
LATE THIS EVENING...IMPROVEMENT TO MVFR/VFR SHOULD COMMENCE FROM
NORTHWEST TO SOUTHEAST.
&&
.LBF WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY UNTIL 7 AM CDT /6 AM MDT/ SUNDAY FOR
NEZ006-008-025-026-036-057-058-069.
WINTER WEATHER ADVISORY UNTIL 7 AM CDT SUNDAY FOR NEZ007-009-010-
027>029-037-038-059-070-071.
WINTER STORM WARNING UNTIL 7 AM CDT /6 AM MDT/ SUNDAY FOR NEZ004-
005-022>024-035-056-094.
&&
$$
UPDATE...JACOBS
SHORT TERM...CDC
LONG TERM...MASEK
AVIATION...JACOBS
AREA FORECAST DISCUSSION
NWS NORTH PLATTE NE
1021 AM CST SAT MAR 9 2013
.UPDATE...
ISSUED AT 1021 CST SAT MAR 9 2013
OVERALL IDEA OF THE FORECAST REMAINS ON TRACK WITH ONLY MINOR
REVISIONS TO FRESHEN UP WIND SPEEDS...TIMING OF THE SNOW
CHANGEOVER...AND FREEZING RAIN AMOUNTS. PHONE CALLS IN AND AROUND
KVTN THIS MORNING SUGGESTED ABOUT A TENTH OF AN INCH OF ICE OR
LESS ACCUMULATION...THUS WILL TREND DOWN THE QUARTER OF AN INCH WE
HAD GOING FOR THE CENTRAL SAND HILLS...WITH WORDING OF MINOR
ICE ACCUMULATIONS. OTHERWISE ONCE THE CHANGE OVER TO SNOW
OCCURS...SNOW RATES OF AN INCH PER HOUR HAVE BEEN NOTED UNDER THE
HEAVIEST OF BANDS. 12Z NAM APPEARS REASONABLE AT THIS
JUNCTURE...THUS TRENDED IN THAT DIRECTION. THE NARROW BAND OF QPF
WILL CONTINUE THROUGH MID AFTERNOON ACROSS NORTHWEST NEBRASKA
ALONG A STRONG BAND OF H7 FRONTOGENESIS AND WITH AID FROM THE LFQ
OF A 90KT JET. SNOW ACCUMULATIONS OF 6 INCHES OR GREATER STILL
APPEARS LIKELY ACROSS NORTHWEST NEBRASKA. BUT LATER TODAY...SNOW
WILL BEGIN TO TAPER OFF BY LATE AFTERNOON AS THE NORTHERN STREAM
RACES SOUTHEAST ACROSS THE NORTHERN PLAINS AND ALLOWS FOR THE
INTRUSION OF DRIER AIR INTO THE NORTHERN REACHES OF THE CWA.
HOWEVER ALL NEAR TERM SOLUTIONS DO INDICATE THE FORMATION OF A
SECOND AREA OF DEFORMATION ACROSS FAR SOUTHEASTERN PORTIONS OF THE
FORECAST AREA...ALIGNED NORTHEAST TO SOUTHWEST WITH THE EASTWARD
ADVANCING MID LEVEL FRONTOGENETIC FORCING...FORECAST FOR THIS
SECOND BAND APPEARS ON TRACK AT THIS TIME...WILL REVISIT EXPECTED
SNOW AMOUNTS AS ADDITIONAL GUIDANCE COMES IN THIS MORNING.
UPDATE ISSUED AT 700 AM CST SAT MAR 9 2013
NO NEW DATA WAS AVAILABLE FOR THE QPF FORECAST BUT INDICATIONS ARE
THE RAP13 IS VERIFYING ACROSS NRN NEB WITH OVER 1/2 INCH OF ICE AT
THE KVTN ASOS. AFTER SLOWING THE EASTERN PROGRESSION OF THE RAIN
CHANGE LINE USING THE RUC...NORTH WINDS HAVE INCREASED AND NOW THE
RAIN CHANGE LINE IS ROUGHLY FROM CHAPPELL TO THEDFORD TO AINSWORTH.
SO THE NAM MAY BE VERIFYING BETTER AND IT WAS USED IN THE NEW
FORECAST.
A NEW WIND FORECAST USING NAM...GEM...MET AND MAV GUIDANCE
PRODUCED GUSTS TO 50 MPH THIS AFTERNOON AND THIS EVENING WHICH IS
CONSISTENT WITH THE 60KT BARRIER JET FCST BY BOTH MODELS. THIS
STRUCTURE IS FCST TO SET UP ACROSS THE ERN PANHANDLE THIS MORNING
AND MOVE SLOWLY EAST THIS AFTN AND TONIGHT ACTING AS A FOCUS FOR
SNOW AND STRONG WINDS.
THERE IS NO CHANGE TO THE DYNAMICS. STRONG FRONTOGENESIS HANGS
UP ACROSS THE NORTHWEST TODAY AND DECAYS WHILE A NEW STRUCTURE
DEVELOPS FARTHER EAST THIS EVENING. THE RAP HAS COME IN LINE WITH
THE NAM AND ECM DEVELOPING THE NEW SNOW EAST OF THE FCST AREA
WHILE THE 06Z GFS HANGS IT UP ACROSS NCNTL AND SWRN NEB...VERY
TROUBLING. GIVEN THE VERY STRONG WINDS DEVELOPING...EVEN AN 1/2
INCH PER HOUR SNOWFALL RATE COULD PRODUCE BLIZZARD CONDITIONS.
THE SNOW SHOULD GRADUALLY END OVERNIGHT AND SUNDAY MORNING WEST TO
EAST WITH CLEARING SKIES TO FOLLOW. WINDY CONDITIONS CONTINUE
SUNDAY MORNING IN THE EAST.
UPDATE ISSUED AT 527 AM CST SAT MAR 9 2013
THE RAP13 MODEL SHOWS A SLOWER TRANSITION TO SNOW THAN THE NAM. IN
FACT THE RAP CARRIES A BROAD AREA OF FREEZING RAIN AHEAD OF THE
CHANGEOVER TO SNOW. THIS IS WELL SUPPORTED IN THE MODEL TEMPERATURE
FIELDS. SO A NEW FORECAST IS OUT WHICH HEIGHTENS THE THREAT OF
FREEZING RAIN.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 345 AM CST SAT MAR 9 2013
TWO ROUNDS OF THOUGHT WITH THE STORM. ONE IS FOR A STRONG FGEN
FORCED BAND OF SNOW DEVELOPING ACROSS NORTHWEST NEBRASKA TODAY
WHICH MOST SOLNS AGREE ON TO VARYING DEGREES. THE SECOND IS FOR
ANOTHER STRONG BAND OF SNOW TO DEVELOP ACROSS SOUTH CENTRAL
NEBRASKA TONIGHT AS THE FIRST BAND DECAYS. THE GEM REGIONAL AND
GFS ARE VERY FAR NORTHWEST WITH THIS BAND SIGNALING A WINTER
STORM FOR NCNTL NEB WHILE THE NAM AND ECM ARE SAFELY EAST OF THE
FCST AREA. A BLEND OF NAM...GEM AND ECM WERE USED FOR THE LATEST
FCST WHICH PROVIDES A WINTER STORM ACROSS THE NORTHWEST AND A
WINTER WEATHER ADVISORY ELSEWHERE.
HOWEVER THE NAM AND RAP SHOW A VERY STRONG BARRIER JET DEVELOPING
THIS EVENING STRETCHING NORTH-SOUTH ALONG AND WEST OF HIGHWAY 83
WHICH COULD EASILY SUPPORT A WINTER STORM IF THE FRONTOGENESIS
WAS APPROPRIATELY JUXTAPOSED. THIS IS NOT THE CASE AS THE NAM
SHOWS THE FGEN AND HEAVY QPF MOSTLY EAST OF THE FCST AREA. THE
RAP MEANWHILE NOSES THE PV1.5 ANOMALY INTO SRN NEB AT 02Z AND
DEVELOPS SOME HEAVY SNOW ACROSS SWRN NEB. THIS IS A CONCERN WHICH
WILL BE CLOSELY MONITORED.
THE STRONG BARRIER JET WILL EASILY SUPPORT 30 MPH WINDS WITH
GUSTS TO 45 MPH. IN FACT THE NAM AND RAP SHOW GUSTS TO 60 MPH AT
00Z-03Z...THE HEIGHT OF THE STORM ACROSS SWRN AND NCNTL NEB.
SO EVERYONE OUTSIDE OF THE WINTER STORM WARNING HAS BEEN PLACED
IN A WINTER WEATHER ADVISORY FOR 3 TO 5 INCHES OF SNOW AND 30 TO
45 MPH WINDS.
.LONG TERM...(SUNDAY THROUGH FRIDAY)
ISSUED AT 345 AM CST SAT MAR 9 2013
MAJOR SPRING/WINTER STORM WILL BE EXITING SUNDAY MORNING WITH
SOME LINGERING LIGHT SNOW ACROSS THE FAR EASTERN COUNTIES. WINDS
WILL CONTINUE TO BE GUSTY...AND WILL HIGHLIGHT PATCHY BLOWING
SNOW WHERE FALLING SNOW IS EXPECTED. PENDING TOTAL SNOW AND HOW
FLUFFY IT IS...MAY NEED TO CONTINUE BLOWING SNOW FURTHER WEST
EARLY SUNDAY. STILL QUESTIONING HOW FAR WEST THE HEAVY BAND OF
SNOW OVER CENTRAL NEB WILL BE.
SUNDAY HIGHS...WITH COLD HIGH PRESSURE BUILDING SOUTH ACROSS THE
NORTHERN PLAINS AND MUCH IF NOT ALL OF THE AREA EXPECTED TO SEE A
SNOW COVER...SHOULD HOLD CLOSE TO 30 DEGREES. ALTHOUGH THE SUN
WILL SPREADING FROM WEST TO EAST...WHICH SHOULD HELP TO START TO
MELT ROADWAYS.
SUNDAY NIGHT WITH AN ELONGATED HIGH ACROSS THE WESTERN
PLAINS...LIGHT WINDS AND MOSTLY CLEAR SKIES ALONG WITH SNOW
PACK...TEMPS SHOULD TANK. WIDESPREAD TEENS...WHICH MAY BE
CONSERVATIVE.
MONDAY INTO MID WEEK RIDGE BUILDS ACROSS THE WEST...WITH A TROUGH
TO PUSH ALONG THE NORTHERN STREAM...ACROSS SOUTHERN CANADA AND
THE GREAT LAKES. WEAK DISTURBANCE TO MOVE ALONG THE NW FLOW
ACROSS THE AREA...HOWEVER MOISTURE LIMITED AND DOUBT ANYTHING
WILL REACH THE GROUND AS TIMING IS A LITTLE SLOWER WITH PASSAGE
MORE OF A DAYTIME AND THE HEAT OF THE DAY SHOULD BE ENOUGH TO
KEEP ANYTHING FROM HITTING THE GROUND. ALSO EARLY IN THE WEEK AS
THE SNOW MELTS WILL NEED TO MONITOR FOR OVERNIGHT/MORNING FOG.
RIDGE EXPANDS AS THE WEEK CONTINUES...WITH STRONG WAA ALOFT WITH
THE WESTERN PART OF THE CWA SEEING DOUBLE DIGIT 850 TEMPS.
QUESTION WILL BE HOW LONG CAN THE SNOW REMAIN AND DAMPEN TEMPS.
GUIDANCE PUSHES HIGHS INTO THE 50S AND 60S FOR WEDNESDAY AND
THURSDAY. AS IS TYPICAL WITH MANY MARCH SNOW STORMS...EXPECT THIS
SNOW NOT TO STAY LONG. ALTHOUGH WEST WINDS ON THE LIGHT
SIDE...LESS THAN 15 MPH...SHOULD BE ENOUGH TO HELP MIX WITH THE
DOWNSLOPE COMPONENT AND HAVE FOLLOWED CLOSER TO GUIDANCE FOR THE
LATER HALF OF THE WEEK.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SUNDAY MORNING)
ISSUED AT 537 AM CST SAT MAR 9 2013
EXPECTING IFR/LIFR TO CONTINUE THROUGH 03Z THIS EVENING IN
SNOW...BLOWING SNOW...FOG...RAIN AND FREEZING RAIN. THEREAFTER AN
IMPROVEMENT TO MVFR/VFR SHOULD COMMENCE FROM NORTHWEST TO
SOUTHEAST. WINDS TODAY WILL INCREASE TO 36030G40KT AND DIMINISH
LATE THIS EVENING TO 34020G30KT BY 12Z SUNDAY.
&&
.LBF WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY UNTIL 7 AM CDT /6 AM MDT/ SUNDAY FOR
NEZ006-008-025-026-036-057-058-069.
WINTER WEATHER ADVISORY UNTIL 7 AM CDT SUNDAY FOR NEZ007-009-010-
027>029-037-038-059-070-071.
WINTER STORM WARNING UNTIL 7 AM CDT /6 AM MDT/ SUNDAY FOR NEZ004-
005-022>024-035-056-094.
&&
$$
UPDATE...JACOBS
SHORT TERM...CDC
LONG TERM...MASEK
AVIATION...CDC
AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NWS RAPID CITY SD
1142 AM MST SAT MAR 9 2013
.UPDATE...
ISSUED AT 1137 AM MST SAT MAR 9 2013
CALLS TO SPOTTERS INDICATE 2 TO 5 INCHES OF SNOW HAS FALLEN ON
PORTIONS OF SOUTH CENTRAL SD...MAINLY FROM SPRING CREEK TO FAR
NORTHWEST TRIPP COUNTY. A BAND OF HEAVY SNOW...LOOKING CONVECTIVE
AT TIMES ON RADAR/SATELLITE...HAS DEVELOPED IN NORTH CENTRAL
NEBRASKA...MOVING INTO SOUTH CENTRAL SD. LATEST RAP MODEL INDICATES
BAND WILL PERSIST FOR SEVERAL MORE HOURS WITH SNOWFALL RATES UP TO
1 INCH PER HOUR. STORM TOTAL SNOW WILL BE 4 TO 9 INCHES...SO HAVE
UPGRADE TO A WARNING FOR TODD...MELLETTE...AND TRIPP COUNTIES.
&&
.SHORT TERM...(TODAY THROUGH SUNDAY NIGHT)
ISSUED AT 303 AM MST SAT MAR 9 2013
SW CONUS UPPER TROUGH CONTINUES TO PUSH ENE TOWARD THE
REGION AS A NORTHERN STREAM TROUGH DROPS SE INTO THE DAKOTAS. VERY
STRONG WAA RESPONSE ONGOING ACROSS THE CENTRAL PLAINS WILL SPREAD
NORTH INTO SOUTH DAKOTA AND CONTINUE TO SUPPORT RAIN/ZR/AND EVEN A
PERIOD OF TS CHANCES THIS MORNING GIVEN STEEP MID LEVEL LAPSE RATES
AND A CONDITIONALLY UNSTABLE LAYER ALOFT. WAA WILL EVENTUALLY
SUPPORT THE DEVELOPMENT OF A PRONOUNCED DEFORMATION ZONE ACROSS
SCENTRAL SD...WITH VIGOROUS DEEP LAYER ASCENT AS THE NORTHERN STREAM
TROUGH DROPS SOUTH AND SUPPORTS DEEP LAYER CAA. A PERIOD OF HEAVY
SNOW CAN BE EXPECTED IN THE DEFORMATION BAND...WITH HIGH LIQUID
WATER CONTENT AND LOW RATIO. THE LOCATION OF THIS SNOW BAND REMAINS
SEMI-ELUSIVE GIVEN THE PRESENCE OF A STRONG WARM NOSE...AND FORECAST
MODELS HAVE WAVERED PER ITS PLACEMENT. HOWEVER...LATEST GUIDANCE
/ESP FROM THE NAM/ HAVE HONED THE LOCATION TO EASTERN TODD/MELLETTE
AND MUCH OF TRIPP COUNTY. OTHERWISE...THE REMAINDER OF THE FA LOOKS
TO BE FAIRLY DRY SAVE PERHAPS A LITTLE LIGHT SNOW OVER THE NORTHERN
HILLS WHICH LOOKS IFFY AT THIS POINT GIVEN A SHARPLY DRYING BL.
SUBSIDING FLOW WILL PREVAIL ON SUNDAY...WITH DEEP LAYER RIDGING AND
DRY CONDITIONS.
ROBUST WAA RESPONSE WILL PUSH NORTH IN SCENTRAL SD THIS
MORNING...SUPPORTING RAIN/FREEZING RAIN/AND SNOW. RAIN AND FREEZING
RAIN IS EXPECTED TO LAST THROUGH MID MORNING OVER PORTIONS OF
MELLETTE/TODD/AND TRIPP COUNTIES WHERE SOME LIGHT ICING UP TO ONE
TENTH OF A INCH WILL BE POSSIBLE UNTIL ALL PRECIP TRANSITIONS TO
SNOW. MAIN LOBE OF DEEP LAYER ASCENT WILL SPREAD INTO SCENTRAL SD
MID TO LATE MORNING...WITH A STRENGTHENING LL DEFORMATION ZONE.
STRONG LIFT CENTERED IN THE SNOW GROWTH ZONE WILL SUPPORT A VERY
INTENSE BAND OF HEAVY SNOW FOR 3-6 HOURS. HEAVY SNOWFALL RATES ARE
EXPECTED WITH LOCATIONS IN THE BAND EXPECTED TO SEE 3-5 INCHES.
LOCALLY HIGHER AMOUNTS WILL BE POSSIBLE BEFORE SNOW TAPERS OFF THIS
EVENING. A SHARP CUT OFF IN PRECIP IS EXPECTED...SUPPORTING MAINLY
DRY CONDITIONS ACROSS THE NW 1/2-2/3. HAVE DROPPED THE WINTER WEATHER
ADV FOR THE TWO NW COUNTIES...GIVEN LACK OF SIG PRECIP. STRONG
PRESSURE RISES WILL ENSUE IN A CAA REGIME SUPPORTING GUSTY NW
WINDS. STRONGEST WINDS WILL BE IN THE LEE OF THE BH AND ADJACENT
PLAINS GIVEN FLOW ENHANCEMENT AROUND THE BH. SUSTAINED WINDS OF 25 TO
30 MPH WITH GUSTS TO AROUND 50 MPH ARE EXPECTED. HAVE ISSUED A WIND
ADV FOR THIS. 15 TO 30 MPH WINDS WILL SPREAD INTO SCNTRL SD THIS
AFTERNOON AND EVENING AND MAY SUPPORT AREAS OF BLOWING SNOW
DEPENDING ON BL TEMPS. MANY FORECAST SOLUTIONS OFFER TEMPS IN LOWER
30S BY AFTERNOON WHICH COULD HAMPER SNOW LIFTING POTENTIAL THERE.
ADJUSTED POPS TO FIT ABOVE CONCERNS...WITH SOME ADJUSTMENT TO TEMPS.
SUNDAY...FAIRLY QUIET WEATHER TO PREVAIL WITH A PERIOD OF SHORTWAVE
RIDGING. WAA EXPECTED TO INFLUENCE TEMPS ACROSS THE WESTERN HALF OF
THE FA...WITH EASTERN AREAS LIKELY REMAINING UNDER A SUBSIDENCE
INVERSION AND CONTINUED NORTHERLY FLOW. SNOW COVER WILL ALSO
INFLUENCE TEMPS OVER SCENTRAL AREAS. LOWS WILL BE TRICKY SUNDAY
NIGHT OVER THE SNOW PACK...WHERE SIG T DROP OFFS ARE POSSIBLE GIVEN
CLEAR SKIES AND LIGHT WINDS.
.LONG TERM...(MONDAY THROUGH FRIDAY)
ISSUED AT 303 AM MST SAT MAR 9 2013
RIDGE BUILDS OVER THE WESTERN CONUS...WITH AXIS SLOWLY SHIFTING
TOWARDS THE PLAINS THROUGH THE EXTENDED. THIS WILL BRING MILD TEMPS
THROUGH MID-WEEK...WITH WARMER TEMPS EXPECTED FOR THE LAST PART OF
THE WORK WEEK. OCCASIONAL WEAK DISTURBANCES MOVING THROUGH MAY BRING
A FEW LIGHT SHOWERS THROUGH MID-WEEK...WITH GENERALLY DRY CONDITIONS
FOR THE END OF THE WORK WEEK.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON)
ISSUED AT 1035 AM MST SAT MAR 9 2013
CONDITIONS IMPROVING OVER NE WY AND EXTRM WRN SD WITH CIGS AND
VSBYS QUICKLY BECOMING VFR EXCEPT SOME LOW CLOUDS PERSISTING OVER
THE BLACK HILLS. ELSEWHERE...OVER S CNTRL SD WIDESPREAD IFR AND
LIFR CIGS AND VSBYS IN SNOW WILL CONTINUE INTO MID AFTN BEFORE
GRADUALLY IMPROVING FROM NW TO SE AS SNOW MOVES OUT OF THE AREA.
LOW CLOUDS WILL PERSIST UNTIL NEAR SUNSET OVER S CNTRL SD. NORTH AND
NORTHWESTERLY WINDS OF 25-30 KTS WITH GUSTS UP TO 40KTS WILL COVER
MOST OF THE FCST AREA...WITH STRONGEST WINDS JUST EAST OF THE
BLACK HILLS BEFORE GRADUALLY DIMINISHING AFTER SUNSET. PATCHY LOW
STRATUS IS LIKELY TO REDEVELOP OVER NE WY AND WRN PORTIONS OF SD
AROUND 06Z TONIGHT.
&&
.UNR WATCHES/WARNINGS/ADVISORIES...
SD...WINTER WEATHER ADVISORY UNTIL 6 PM MST THIS EVENING FOR SDZ044.
WINTER STORM WARNING UNTIL 7 PM CST THIS EVENING FOR SDZ046-047-
049.
WIND ADVISORY UNTIL 7 PM MST THIS EVENING FOR SDZ026-030-031-
072>074.
WY...NONE.
&&
$$
UPDATE...HELGESON
SHORT TERM...JC
LONG TERM...77
AVIATION...BARBER
AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NWS RAPID CITY SD
1038 AM MST SAT MAR 9 2013
.UPDATE...
ISSUED AT 855 AM MST SAT MAR 9 2013
15Z SURFACE ANALYSIS HAD LOW OVER SOUTHEAST CO WITH NEARLY
STATIONARY BOUNDARY INTO EASTERN ND. FIRST IMPULSE FROM STORM
SYSTEM BROUGHT A BRIEF PERIOD OF -FZRA TO SOUTH CENTRAL SD...BUT
CALLS TO SPOTTERS INDICATE CHANGEOVER TO SN HAS OCCURRED WITH 1-2
INCHES IN THE LAST COUPLE OF HOURS. 12Z RAP HAD A GOOD HANDLE ON
CURRENT SENSIBLE WEATHER. NARROW BAND OF -SN/SN WILL CONTINUE
THROUGH THIS AFTERNOON OVER SOUTH CENTRAL SD AS MAIN IMPULSE MOVES
NORTHEAST INTO THE CENTRAL PLAINS. SNOW COINCIDENT WITH STRONG
BAND OF 850-700MB FRONTOGENESIS...NORTHERN EDGE OF 700-500MB QG-
FORCING...AND UNDER LEFT EXIT REGION OF 90KT JET STREAK RACING UP
FRONT SIDE OF UPPER TROUGH OVER CO/NM. NORTHERN STREAM TROUGH WILL
RACE SOUTHEAST...BRINGING MUCH DRIER AIR INTO CWA...AND THUS...AN
END TO LINGERING -SN OVER NORTHWEST 2/3RDS OF CWA. 25-30KT 850MB
WINDS WILL MIX OVER NORTHWEST SD LEADING TO WINDY CONDITIONS AS IN
CURRENT FORECAST. UPDATE OUT SHORTLY.
&&
.SHORT TERM...(TODAY THROUGH SUNDAY NIGHT)
ISSUED AT 303 AM MST SAT MAR 9 2013
SW CONUS UPPER TROUGH CONTINUES TO PUSH ENE TOWARD THE
REGION AS A NORTHERN STREAM TROUGH DROPS SE INTO THE DAKOTAS. VERY
STRONG WAA RESPONSE ONGOING ACROSS THE CENTRAL PLAINS WILL SPREAD
NORTH INTO SOUTH DAKOTA AND CONTINUE TO SUPPORT RAIN/ZR/AND EVEN A
PERIOD OF TS CHANCES THIS MORNING GIVEN STEEP MID LEVEL LAPSE RATES
AND A CONDITIONALLY UNSTABLE LAYER ALOFT. WAA WILL EVENTUALLY
SUPPORT THE DEVELOPMENT OF A PRONOUNCED DEFORMATION ZONE ACROSS
SCENTRAL SD...WITH VIGOROUS DEEP LAYER ASCENT AS THE NORTHERN STREAM
TROUGH DROPS SOUTH AND SUPPORTS DEEP LAYER CAA. A PERIOD OF HEAVY
SNOW CAN BE EXPECTED IN THE DEFORMATION BAND...WITH HIGH LIQUID
WATER CONTENT AND LOW RATIO. THE LOCATION OF THIS SNOW BAND REMAINS
SEMI-ELUSIVE GIVEN THE PRESENCE OF A STRONG WARM NOSE...AND FORECAST
MODELS HAVE WAVERED PER ITS PLACEMENT. HOWEVER...LATEST GUIDANCE
/ESP FROM THE NAM/ HAVE HONED THE LOCATION TO EASTERN TODD/MELLETTE
AND MUCH OF TRIPP COUNTY. OTHERWISE...THE REMAINDER OF THE FA LOOKS
TO BE FAIRLY DRY SAVE PERHAPS A LITTLE LIGHT SNOW OVER THE NORTHERN
HILLS WHICH LOOKS IFFY AT THIS POINT GIVEN A SHARPLY DRYING BL.
SUBSIDING FLOW WILL PREVAIL ON SUNDAY...WITH DEEP LAYER RIDGING AND
DRY CONDITIONS.
ROBUST WAA RESPONSE WILL PUSH NORTH IN SCENTRAL SD THIS
MORNING...SUPPORTING RAIN/FREEZING RAIN/AND SNOW. RAIN AND FREEZING
RAIN IS EXPECTED TO LAST THROUGH MID MORNING OVER PORTIONS OF
MELLETTE/TODD/AND TRIPP COUNTIES WHERE SOME LIGHT ICING UP TO ONE
TENTH OF A INCH WILL BE POSSIBLE UNTIL ALL PRECIP TRANSITIONS TO
SNOW. MAIN LOBE OF DEEP LAYER ASCENT WILL SPREAD INTO SCENTRAL SD
MID TO LATE MORNING...WITH A STRENGTHENING LL DEFORMATION ZONE.
STRONG LIFT CENTERED IN THE SNOW GROWTH ZONE WILL SUPPORT A VERY
INTENSE BAND OF HEAVY SNOW FOR 3-6 HOURS. HEAVY SNOWFALL RATES ARE
EXPECTED WITH LOCATIONS IN THE BAND EXPECTED TO SEE 3-5 INCHES.
LOCALLY HIGHER AMOUNTS WILL BE POSSIBLE BEFORE SNOW TAPERS OFF THIS
EVENING. A SHARP CUT OFF IN PRECIP IS EXPECTED...SUPPORTING MAINLY
DRY CONDITIONS ACROSS THE NW 1/2-2/3. HAVE DROPPED THE WINTER WEATHER
ADV FOR THE TWO NW COUNTIES...GIVEN LACK OF SIG PRECIP. STRONG
PRESSURE RISES WILL ENSUE IN A CAA REGIME SUPPORTING GUSTY NW
WINDS. STRONGEST WINDS WILL BE IN THE LEE OF THE BH AND ADJACENT
PLAINS GIVEN FLOW ENHANCEMENT AROUND THE BH. SUSTAINED WINDS OF 25 TO
30 MPH WITH GUSTS TO AROUND 50 MPH ARE EXPECTED. HAVE ISSUED A WIND
ADV FOR THIS. 15 TO 30 MPH WINDS WILL SPREAD INTO SCNTRL SD THIS
AFTERNOON AND EVENING AND MAY SUPPORT AREAS OF BLOWING SNOW
DEPENDING ON BL TEMPS. MANY FORECAST SOLUTIONS OFFER TEMPS IN LOWER
30S BY AFTERNOON WHICH COULD HAMPER SNOW LIFTING POTENTIAL THERE.
ADJUSTED POPS TO FIT ABOVE CONCERNS...WITH SOME ADJUSTMENT TO TEMPS.
SUNDAY...FAIRLY QUIET WEATHER TO PREVAIL WITH A PERIOD OF SHORTWAVE
RIDGING. WAA EXPECTED TO INFLUENCE TEMPS ACROSS THE WESTERN HALF OF
THE FA...WITH EASTERN AREAS LIKELY REMAINING UNDER A SUBSIDENCE
INVERSION AND CONTINUED NORTHERLY FLOW. SNOW COVER WILL ALSO
INFLUENCE TEMPS OVER SCENTRAL AREAS. LOWS WILL BE TRICKY SUNDAY
NIGHT OVER THE SNOW PACK...WHERE SIG T DROP OFFS ARE POSSIBLE GIVEN
CLEAR SKIES AND LIGHT WINDS.
.LONG TERM...(MONDAY THROUGH FRIDAY)
ISSUED AT 303 AM MST SAT MAR 9 2013
RIDGE BUILDS OVER THE WESTERN CONUS...WITH AXIS SLOWLY SHIFTING
TOWARDS THE PLAINS THROUGH THE EXTENDED. THIS WILL BRING MILD TEMPS
THROUGH MID-WEEK...WITH WARMER TEMPS EXPECTED FOR THE LAST PART OF
THE WORK WEEK. OCCASIONAL WEAK DISTURBANCES MOVING THROUGH MAY BRING
A FEW LIGHT SHOWERS THROUGH MID-WEEK...WITH GENERALLY DRY CONDITIONS
FOR THE END OF THE WORK WEEK.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON)
ISSUED AT 1035 AM MST SAT MAR 9 2013
CONDITIONS IMPROVING OVER NE WY AND EXTRM WRN SD WITH CIGS AND
VSBYS QUICKLY BECOMING VFR EXCEPT SOME LOW CLOUDS PERSISTING OVER
THE BLACK HILLS. ELSEWHERE...OVER S CNTRL SD WIDESPREAD IFR AND
LIFR CIGS AND VSBYS IN SNOW WILL CONTINUE INTO MID AFTN BEFORE
GRADUALLY IMPROVING FROM NW TO SE AS SNOW MOVES OUT OF THE AREA.
LOW CLOUDS WILL PERSIST UNTIL NEAR SUNSET OVER S CNTRL SD. NORTH AND
NORTHWESTERLY WINDS OF 25-30 KTS WITH GUSTS UP TO 40KTS WILL COVER
MOST OF THE FCST AREA...WITH STRONGEST WINDS JUST EAST OF THE
BLACK HILLS BEFORE GRADUALLY DIMINISHING AFTER SUNSET. PATCHY LOW
STRATUS IS LIKELY TO REDEVELOP OVER NE WY AND WRN PORTIONS OF SD
AROUND 06Z TONIGHT.
&&
.UNR WATCHES/WARNINGS/ADVISORIES...
SD...WINTER WEATHER ADVISORY UNTIL 5 PM MST /6 PM CST/ THIS AFTERNOON
FOR SDZ044-046-047-049.
WIND ADVISORY UNTIL 7 PM MST THIS EVENING FOR SDZ026-030-031-
072>074.
WY...NONE.
&&
$$
UPDATE...HELGESON
SHORT TERM...JC
LONG TERM...77
AVIATION...BARBER
AREA FORECAST DISCUSSION...UPDATED
NWS SAN ANGELO TX
212 PM CST SAT MAR 9 2013
.UPDATE...
FORECAST WAS UPDATED TO INCREASE POPS ACROSS EASTERN SECTIONS
THIS AFTERNOON AND TO INCLUDE SEVERE THUNDERSTORM WATCH 49.
&&
.DISCUSSION...
CONVECTION CONTINUES TO INCREASE ALONG THE PACIFIC FRONT/DRYLINE
EARLY THIS AFTERNOON WHICH CURRENTLY EXTENDS FROM JUST EAST OF
ABILENE...SOUTHWEST TO NEAR OZONA. LATEST RUC SEEMS TO HAVE A
DECENT HANDLE ON CURRENT ACTIVITY AND INDICATES ADDITIONAL
DEVELOPMENT ACROSS EASTERN PORTIONS THE HEARTLAND AND NORTHWEST
HILL COUNTRY LATER THIS AFTERNOON. PER SPC COORDINATION...SEVERE
THUNDERSTORM WATCH IS IN NOW IN EFFECT UNTIL 11 PM FOR THE
HEARTLAND AND CALLAHAN COUNTY. INCREASED POPS ACCORDINGLY ACROSS
EASTERN SECTIONS AND MADE ADJUSTMENTS TO TEMPS...DEWPOINTS AND
WINDS TO ACCOUNT FOR TRENDS. UPDATED ZONES SENT.
THUNDERSTORMS ARE EXPECTED TO INCREASE IN COVERAGE ACROSS THE
HEARTLAND AND NORTHWEST HILL COUNTRY LATER THIS EVENING WITH AN
ADDITIONAL THREAT FOR SEVERE STORMS INTO THE OVERNIGHT HOURS. THE
MAIN SEVERE WEATHER THREAT THIS AFTERNOON THROUGH TONIGHT WILL BE
LARGE HAIL AND DAMAGING WINDS BUT AN ISOLATED TORNADO CANNOT BE
RULED OUT.
&&
.PREV DISCUSSION... /ISSUED 1201 PM CST SAT MAR 9 2013/
DISCUSSION...
SEE 18Z AVIATION DISCUSSION.
AVIATION...
MAINLY AND MVFR FORECAST OVER THE NEXT 24 HOURS. SHOWERS AND
THUNDERSTORMS ARE POSSIBLE ACROSS MOST OF WEST CENTRAL TEXAS TODAY
AND INTO THIS EVENING AS A PACIFIC FRONT MOVE ACROSS THE AREA.
SHOWERS AND ISOLATED THUNDERSTORMS ARE POSSIBLE OVER
KABI...KSJT AND KSOA THROUGH MID AFTERNOON BUT CONFIDENCE NOT HIGH
ENOUGH TO INCLUDE ANYTHING BUT VICINITY FOR NOW. EXPECT MORE
CONVECTION TO DEVELOP OVER THE SOUTHEAST TERMINALS LATER THIS
EVENING. WILL INCLUDE VCTS OVER KBBD AND KJCT 03-06Z AND AND
REFINE THE FORECAST AS NEEDED BASED ON TRENDS. STORMS ARE
EXPECTED TO CLEAR OUT TOMORROW MORNING AFTER 10Z WITH A COLD
MOVING ACROSS THE AREA SUNDAY MORNING. EXPECT GUSTY NORTH TO
NORTHWEST WINDS BEHIND THE FRONT TO PERSIST INTO THE AFTERNOON
HOURS.
PREV DISCUSSION... /ISSUED 539 AM CST SAT MAR 9 2013/
DISCUSSION...
SEE THE 12Z AVIATION DISCUSSION BELOW.
AVIATION...
WIDESPREAD MVFR CIGS ARE AFFECTING MUCH OF WEST CENTRAL TX.
HOWEVER...IT APPEARS THAT GRAVITY WAVES ASSOCIATED WITH THE VERY
STRONG LOW LEVEL JET HAVE RESULTED IN AREAS OF SUBSIDENCE ON THE
LEE SIDE OF THE HIGHER TERRAIN FEATURES...CREATING EAST/WEST
CORRIDORS OF VFR CONDITIONS AT BOTH KABI AND KSJT. THESE AREAS
MAY BRIEFLY FILL IN BUT AS DRIER AIR ADVECTS INTO THE AREA WE WILL
SEE IMPROVING CIG HEIGHTS. CIGS ARE EXPECTED TO HANG ON THE
LONGEST AT KABI/KJCT BUT THESE AREAS SHOULD EVENTUALLY GO VFR AS
WELL BY MIDDAY. WINDS WILL VEER TO THE WEST SOUTHWEST AND REMAIN
GUSTY THIS MORNING. THESE GUSTY CONDITIONS WILL CONTINUE AT
KSJT/KABI BUT THE REMAINING AREAS SHOULD SEE SUSTAINED WINDS
GENERALLY 12 KTS OR LESS THIS AFTERNOON. A SECONDARY COLD FRONT
WILL MOVE ACROSS THE CWA OVERNIGHT AND SHIFT WINDS TO THE
NORTHWEST.
THE OTHER CONCERN THIS TAF PERIOD IS CONVECTION. A POTENT SYSTEM
WILL PROVIDE ISOLATED LIGHT RAIN SHOWERS THIS MORNING BUT THE
PRIMARY FOCUS WILL BE THIS EVENING IN THE VICINITY OF A PACIFIC
COLD FRONT...MAINLY OVER THE SOUTHEAST TERMINALS. I DID INCLUDE A
PROB30 GROUP FOR THUNDER AND MVFR CIGS AT KBBD/KJCT BEGINNING AT
23Z AS THUNDERSTORMS ARE EXPECTED TO DEVELOP IN THIS AREA AFTER
PEAK HEATING.
JOHNSON
PREV DISCUSSION... /ISSUED 403 AM CST SAT MAR 9 2013/
SHORT TERM...
A BROAD TROUGH CONTINUES TO MOVE SLOWLY ACROSS THE WESTERN
CONUS...WITH THE PRIMARY CIRCULATION CURRENTLY LOCATED NEAR THE
FOUR CORNERS. SYNOPTIC SCALE ASCENT WILL CONTINUE TO OVERSPREAD
THE REGION AS THIS CYCLONE APPROACHES...INTERACTING WITH MORE
FOCUSED MESOSCALE FORCING AND ABUNDANT LOWER TROPOSPHERIC MOISTURE
TO ENHANCE CLOUD COVER AND PRECIP CHANCES. THE DYNAMICALLY
ENHANCED LOW LEVEL JET IS HOWLING AT AROUND 50 KTS...BUT THE CORE
OF THIS JET WILL SHIFT EAST DURING THE DAY AS THE TROUGH AXIS
MOVES INTO WEST CENTRAL TX. SOUTH WINDS ARE CURRENTLY 20-30 MPH AT
MANY AREAS WITH TEMPS IN THE LOW TO MID 60S.
LIGHT RAIN SHOWERS HAVE DEVELOPED IN THE PAST HOUR OVER WESTERN
NORTH TX...FROM ASPERMONT TO VERNON...AND SHOULD CONTINUE THIS
TREND OVER THE NEXT SEVERAL HOURS. LIGHT RAIN SHOWERS WILL BE
POSSIBLE ACROSS WEST CENTRAL TX THROUGH 18Z AND SHOULD BECOME MORE
ORGANIZED AS THE SURFACE TROUGH /OR WEAK PACIFIC COLD FRONT/ MOVES
EAST AND PROVIDES A STRONG LIFTING MECHANISM. OPTIMISTICALLY
SPEAKING...I THINK WE WILL SEE A BROKEN LINE OF SHOWERS MOVE
ACROSS THE BIG COUNTRY AND CONCHO VALLEY BETWEEN 12-18Z...SHIFTING
INTO THE HEARTLAND AND EASTERN BIG COUNTRY AFTER 18Z. POINT
SOUNDINGS STILL INDICATE THE PRESENCE OF AN ELEVATED MIXED
LAYER...WHICH IS EFFECTIVELY ERODED BY 16Z OR SO.
UNFORTUNATELY...THE BEST LIFT WILL BE OVER THE EASTERN ZONES BY
THIS TIME...MEANING THAT DEEP CONVECTION IS UNLIKELY FOR THE
WESTERN COUNTIES AND ONLY LIGHT PRECIPITATION IS ANTICIPATED THIS
MORNING. TEMPS WILL WARM INTO THE LOW/MID 70S ACROSS THE CWA THIS
AFTERNOON.
AS THE SURFACE BOUNDARY SLOWS UP OVER THE EASTERN ZONES...THE
LARGE SCALE ASCENT WILL CATCH UP AND ENHANCE THUNDERSTORM
CHANCES DURING THE AFTERNOON/EVENING. WITH THE CAP GONE...UPDRAFTS
SHOULD BE ABLE TO TAP INTO THE ANTICIPATED 1000-1500 J/KG OF
INSTABILITY. STRONG DEEP LAYER SHEAR SHOULD PROMOTE ORGANIZED
CONVECTION THIS AFTERNOON AND EVENING...MAINLY SOUTHEAST OF A
BROWNWOOD TO SONORA LINE. SEVERE STORMS WILL BE A POSSIBILITY
ACROSS THE SOUTHEAST THIS EVENING... WITH THE PRIMARY THREATS
BEING LARGE HAIL AND DAMAGING WINDS. THIS CONVECTION WILL LIKELY
CONTINUE ACROSS THE SOUTHEAST ZONES THROUGH 06Z BEFORE SLOWLY
SHIFTING TO THE SOUTH AS DRIER AIR ADVECTS INTO THE CWA FROM THE
WEST.
JOHNSON
LONG TERM...
NEXT WEEK APPEARS DRY IN THE COMPUTER MODELS. MID/UPPER LEVEL
MOISTURE SUNDAY MORNING WILL PUSH EAST AS THE AXIS OF AN UPPER
SHORTWAVE MOVES THROUGH THE REGION. IT WILL BE WINDY SUNDAY WITH
A TIGHT PRESSURE GRADIENT BEHIND A COLD FRONT. ALOFT...DRY
NORTHWEST FLOW WILL BECOME ZONAL BY TUESDAY. CLEAR SKIES AND
LIGHT WINDS ASSOCIATED WITH SURFACE RIDGING WILL BRING GOOD
RADIATIONAL COOLING MONDAY AND TUESDAY MORNINGS...WITH LOW LYING
AREAS FALLING BELOW THE FREEZING MARK. THERE WILL BE NICE REBOUND
IN TEMPERATURES TUESDAY WITH RETURN OF SOUTHERLY WINDS. A DRY
ATMOSPHERE AND SUNNY SKIES...WILL OTHERWISE ALLOW A LARGE DIURNAL
VARIATION IN TEMPERATURE NEXT WEEK.
FIRE WEATHER...
CRITICAL FIRE WEATHER CONDITIONS ARE EXPECTED TODAY DURING THE
MID/LATE AFTERNOON HOURS ACROSS THE WESTERN BIG COUNTRY AND
NORTHWEST CONCHO VALLEY. WEST SOUTHWEST 20 FT WINDS ARE EXPECTED
TO INCREASE TO 20 MPH IN THE WAKE OF A PACIFIC COLD FRONT WITH
RELATIVE HUMIDITY VALUES FALLING TO 15 TO 20 PERCENT. THE CRITICAL
FIRE WEATHER AREA WILL GENERALLY REMAIN ALONG/WEST OF A LINE FROM
HASKELL TO ROBERT LEE. WE MAY SEE A FEW SHOWERS THIS MORNING BUT
FINE FUELS ARE EXPECTED TO QUICKLY DRY. FARTHER SOUTH...WIND
SPEEDS ARE EXPECTED TO REMAIN 15-20 MPH...RESULTING IN ELEVATED
FIRE WEATHER CONDITIONS. RELATIVE HUMIDITIES WILL RECOVER TO 50-60
PERCENT TONIGHT WITH WEST TO NORTHWEST 20 FT WINDS GENERALLY 15
MPH OR LESS. EXPECT NORTH 20 FT WINDS OF 15-25 MPH ON SUNDAY AS A
SECONDARY COLD FRONT MOVES THROUGH THE AREA. HOWEVER...COOLER
CONDITIONS WILL KEEP RELATIVE HUMIDITIES ABOVE 20 PERCENT. MINIMUM
RELATIVE HUMIDITIES WILL FALL TO NEAR 15 PERCENT ON MONDAY WITH 20
FT WINDS WILL REMAIN UNDER 15 MPH. THE REST OF THE WEEK LOOKS
RELATIVELY QUIET.
JOHNSON
&&
.PRELIMINARY POINT TEMPS/POPS...
ABILENE 74 41 55 27 60 / 20 10 5 5 0
SAN ANGELO 79 42 59 28 66 / 20 10 5 5 0
JUNCTION 79 46 63 25 66 / 20 80 10 5 0
&&
.SJT WATCHES/WARNINGS/ADVISORIES...
RED FLAG WARNING UNTIL 6 PM CST THIS EVENING FOR THE FOLLOWING
ZONES: COKE...FISHER...HASKELL...JONES...NOLAN...STERLING.
&&
$$
99/99
AREA FORECAST DISCUSSION
NWS LUBBOCK TX
1142 AM CST SAT MAR 9 2013
.AVIATION...
GUSTY WESTERLY WINDS SUSTAINED AT 25-30 KTS WILL BE COMMON AT THE
TERMINALS THROUGH THE AFTERNOON HOURS...AND A AWW REMAIN IN EFFECT
AT KLBB THROUGH 23Z. THESE WINDS WILL CONTINUE TO LOFT BLDU WHICH
MAY DROP VISIBILITIES INTO MVFR LEVELS AT KLBB. IN ADDITION...A
FEW SPRINKLES COULD LOCALLY ENHANCE THE WINDS AT KLBB INTO EARLY
THIS AFTERNOON. THE WINDS WILL GRADUALLY EASE A BIT THIS EVENING
BUT ANOTHER COLD FRONT WILL MOVE THROUGH EARLY SUNDAY MORNING.
WINDS WILL INCREASE AND SHIFT TO THE NORTH BEHIND THE FRONT AND
SPEEDS COULD AGAIN APPROACH AWW CRITERION. IN ADDITION...SCT-BKN
LOW CLOUDS MAY FILL IN BEHIND THE FRONT...AND COULD THREATEN OR
BREACH MVFR LEVELS.
&&
.PREV DISCUSSION... /ISSUED 1049 AM CST SAT MAR 9 2013/
UPDATE...
ONGOING FORECAST REMAINS IN GOOD SHAPE. PACIFIC FRONT HAS CLEARED
ALL BUT THE FAR SOUTHEAST ZONES AS OF 1030 AM. THUS...HAVE TRIMMED
POPS FOR ALL BUT THE FAR SOUTHEAST ZONES WHERE A FEW SHOWERS AND
ISOLATED STORMS WILL BE POSSIBLE FOR THE NEXT HOUR OR TWO. BEHIND
THE FRONT...GUSTY WESTERLY WIND WERE ALREADY SPILLING IN FROM
EASTERN NEW MEXICO WHERE SUSTAINED WINDS SPEEDS OF 30 TO 35 MPH
WERE ALREADY NOTED IN THE WTM DATA AT HOBBS...TATUM...DORA AND
MORTON. THESE STOUT WESTERLY WINDS WILL OVERSPREAD THE REMAINDER
OF THE FA THROUGH THE LATE MORNING AND INTO THE AFTERNOON HOURS.
THE LATEST RAP AND WRF-NAM DO INDICATE THE STRONGEST LOW TO MIDDLE
LEVEL WIND CORES WILL BE POSITIONED ACROSS THE TEXAS PANHANDLE
AND OVER THE SOUTHERN SOUTH AND ROLLING PLAINS INTO THE NORTHERN
PERMIAN BASIN THIS AFTERNOON. THIS MAY BE WHERE THE STRONGEST
WINDS OCCUR THROUGH THE AFTERNOON HOURS...THOUGH THE ENTIRE CWA
SHOULD SEE SUSTAINED WESTERLY WINDS OF 25 TO 35 MPH...INITIALLY ON
THE CAPROCK AND THEN SPREADING INTO THE ROLLING PLAINS THIS
AFTERNOON. ONGOING WIND ADVISORY REMAINS VALID. IN ADDITION...THE
GUSTY WINDS WILL ADVECT IN MUCH DRIER AIR AND LEAD TO A PERIOD OF
ELEVATED TO CRITICAL FIRE WEATHER THIS AFTERNOON...THOUGH THE
STATE OF THE FUELS SHOULD HELP MITIGATE THE OVERALL FIRE DANGER AND
THE ONGOING FIRE DANGER STATEMENT REMAINS VALID. WINDS WILL
DECREASE THIS EVENING...BUT THEY WILL BE REINVIGORATED EARLY
SUNDAY BEHIND A CANADIAN COLD FRONT.
PREV DISCUSSION... /ISSUED 449 AM CST SAT MAR 9 2013/
SHORT TERM...
DRYLINE HAS REMAINED STATIONED OVER EASTERN NEW MEXICO THIS MORNING
AS UPPER LOW CONTINUES SPINNING NEAR THE FOUR CORNERS REGION. EXPECT
THIS FEATURE AND ASSOCIATED LIFT TO PUSH QUICKLY EAST WITH SOME
ADDITIONAL SHOWER AND THUNDERSTORM ACTIVITY FORMING ALONG THE
ATTENDANT PACIFIC FRONT. BOUNDARY LAYER STABILIZATION WILL LIKELY
LIMIT THE SEVERITY OF ANY STORMS THAT DEVELOP...BUT ELEVATED
INSTABILITY OWING TO STEEPENING LAPSE RATES WILL NONETHELESS PROMOTE
THE THREAT OF SOME SMALL SIZED HAIL IF STORMS CAN BECOME
ESTABLISHED IN OUR REGION.
FOCUS WILL QUICKLY TURN TO DRIER AND WINDIER CONDITIONS IN WAKE OF
THIS LOW. AN INCREASING PRESSURE GRADIENT WILL DEVELOP AS THE UPPER
LOW PUSHES TOWARD WESTERN KANSAS AND CAUSES A SURFACE LOW TO DEEPEN.
WHILE THE 200 NAUTICAL MILE H70 HEIGHT GRADIENT HAS TRENDED DOWNWARD
TO NEAR 70 METERS...SUSTAINED SURFACE WINDS OF 30-35 MPH STILL LOOK
INEVITABLE...THUS WARRANTING A WIND ADVISORY FROM 16-00Z TODAY.
TROPOSPHERIC WIND MAXIMUMS WILL QUICKLY PUSH EAST THIS AFTERNOON
OVER THE ROLLING PLAINS...NEGATING HIGH WIND WARNING CRITERIA ON THE
FAVORED CAPROCK. BLOWING DUST WILL BE A CONCERN...ESPECIALLY ON THE
CAPROCK. HIGHER RAINFALL AMOUNTS AND COVERAGE LAST NIGHT AND THIS
MORNING WOULD HAVE LIMITED THIS POTENTIAL...BUT LOCATIONS SOUTHWEST
OF LUBBOCK GENERALLY ONLY PICKED UP A FEW HUNDREDTHS OF AN INCH.
AREAS AROUND PLAINVIEW TO LITTLEFIELD AND NORTHWEST RECEIVED A
QUARTER OF AN INCH WITH ISOLATED REPORTS UP TO NEAR HALF AN
INCH...BUT WIDESPREAD SIGNIFICANT RAIN BY AND LARGE WAS NOT THE RULE
AS SITES SOUTH AND EAST OF LUBBOCK REMAINED DRY.
A NORTHWEST TO SOUTHEAST GRADIENT IN TEMPERATURES WILL OCCUR THIS
AFTERNOON AS THE COOL NATURED PACIFIC FRONT PUSHES THROUGH...RANGING
FROM THE UPPER 50S ACROSS NORTHWEST ZONES TO MID 70S FOR THE
SOUTHEASTERN REACHES OF THE FORECAST AREA.
A CANADIAN FRONT WILL MOVE THROUGH TONIGHT FROM THE NORTHWEST AND KEEP
WINDS IN THE 15-25 MPH RANGE. COLD AIR ADVECTION WILL AID IN COOLING
OVERNIGHT LOWS INTO THE UPPER 20S TO MID 30S WEST OF THE
ESCARPMENT...WHILE AREAS TO THE EAST WILL ONLY BOTTOM OUT IN THE
UPPER 30S TO AROUND 40.
LONG TERM...
BY SUNDAY MORNING...THIS MORNING/S WEATHER MAKER SHOULD BE SITUATED
OVER THE CENTRAL PLAINS WITH A TROUGH TRAILING BACK TO THE BAJA
PENINSULA. A SUBTENDING LOBE WILL ROTATE AROUND THE BACK SIDE OF THE
LOW ON SUNDAY BRINGING A BIT OF REINFORCING ENERGY FOR A CANADIAN
FRONT DUE IN TONIGHT. NORTHWEST FLOW WILL THEN PERSIST FOR THE
REMAINDER OF THE EXTENDED THOUGH SLOWLY FLATTENING AS NEGATIVELY
TILTED RIDGE EXTENDS FROM THE DESERT SOUTHWEST INTO EXTREME WESTERN
CANADA.
AS FRONT PUSHES THROUGH EARLY SUNDAY...CONVECTION LOOKS TO BREAK
OUT TO OUR SOUTHEAST AND CONTINUE IN THAT DIRECTION. TO OUR
NORTH...SOME LIGHT WRAP-AROUND PRECIPITATION SHOULD BE ABLE TO GET
GOING ON THE WESTERN PERIPHERY OF THE UPPER LOW AND MAY MAKE IT AS
FAR SOUTH AS THE TEXAS PANHANDLE. STILL...WILL KEEP FORECAST DRY
FOR OUR CWFA. WINDS WILL BE QUITE STOUT ON SUNDAY BEHIND THE FRONT
WITH SPEEDS IN THE 20 TO 30 MPH RANGE. AFTER RETURN FLOW STARTS TO
GET GOING LATE MONDAY...NEXT WEAK FRONT WILL TRY TO MAKE IT INTO
THE NORTHWESTERN PANHANDLE TUESDAY MORNING AND AGAIN THURSDAY AND
SATURDAY MORNINGS WITH LITTLE TO SHOW OTHER THAN A WIND SHIFT. DRY
CONDITIONS TO PREVAIL WITH LOTS OF SUN FOR SPRING BREAK.
FIRE WEATHER...
MUCH DRIER AND WINDIER CONDITIONS BEHIND A PACIFIC FRONT WILL DROP
MINIMUM RELATIVE HUMIDITY VALUES INTO THE TEENS TO LOW 20S AREAWIDE.
PORTIONS OF THE SOUTHERN SOUTH PLAINS WILL DIP TO 15 PERCENT OR
BELOW ALONG WITH MUCH OF THE ROLLING PLAINS WHERE TEMPERATURES WILL
BE WARMER. WINDS WILL BE SUSTAINED AROUND 30 MPH WITH GUSTS OF 40-50
MPH. TEMPERATURES NOT TOO FAR ABOVE AVERAGE...A LACK OF DRY
FUELS...AND A QUICKLY EASTWARD MOVING MID LEVEL JET MAXIMUM SHOULD
PRECLUDE WIDESPREAD AND LONG DURATION RED FLAG MINUTES. WILL STILL
EXPERIENCE ELEVATED TO CRITICAL CONDITIONS THIS AFTERNOON...SO WILL
ISSUE A FIRE DANGER STATEMENT TO CONVEY THIS THREAT.
&&
.PRELIMINARY POINT TEMPS/POPS...
FRIONA 57 27 47 25 60 / 0 0 0 0 0
TULIA 60 31 45 23 61 / 10 0 0 0 0
PLAINVIEW 61 31 47 23 62 / 10 0 0 0 0
LEVELLAND 63 33 51 27 64 / 0 0 0 0 0
LUBBOCK 64 34 50 26 63 / 10 0 0 0 0
DENVER CITY 63 33 52 29 63 / 0 0 0 0 0
BROWNFIELD 65 35 52 28 64 / 10 0 0 0 0
CHILDRESS 70 37 50 29 60 / 10 0 0 0 0
SPUR 69 40 52 28 62 / 10 0 0 0 0
ASPERMONT 76 39 52 29 61 / 30 0 0 0 0
&&
.LUB WATCHES/WARNINGS/ADVISORIES...
WIND ADVISORY UNTIL 6 PM CST THIS EVENING FOR THE FOLLOWING
ZONES: TXZ021>044.
&&
$$
23/07/23
AREA FORECAST DISCUSSION...UPDATED
NWS LUBBOCK TX
1049 AM CST SAT MAR 9 2013
.UPDATE...
ONGOING FORECAST REMAINS IN GOOD SHAPE. PACIFIC FRONT HAS CLEARED
ALL BUT THE FAR SOUTHEAST ZONES AS OF 1030 AM. THUS...HAVE TRIMMED
POPS FOR ALL BUT THE FAR SOUTHEAST ZONES WHERE A FEW SHOWERS AND
ISOLATED STORMS WILL BE POSSIBLE FOR THE NEXT HOUR OR TWO. BEHIND
THE FRONT...GUSTY WESTERLY WIND WERE ALREADY SPILLING IN FROM
EASTERN NEW MEXICO WHERE SUSTAINED WINDS SPEEDS OF 30 TO 35 MPH
WERE ALREADY NOTED IN THE WTM DATA AT HOBBS...TATUM...DORA AND
MORTON. THESE STOUT WESTERLY WINDS WILL OVERSPREAD THE REMAINDER
OF THE FA THROUGH THE LATE MORNING AND INTO THE AFTERNOON HOURS.
THE LATEST RAP AND WRF-NAM DO INDICATE THE STRONGEST LOW TO MIDDLE
LEVEL WIND CORES WILL BE POSITIONED ACROSS THE TEXAS PANHANDLE
AND OVER THE SOUTHERN SOUTH AND ROLLING PLAINS INTO THE NORTHERN
PERMIAN BASIN THIS AFTERNOON. THIS MAY BE WHERE THE STRONGEST
WINDS OCCUR THROUGH THE AFTERNOON HOURS...THOUGH THE ENTIRE CWA
SHOULD SEE SUSTAINED WESTERLY WINDS OF 25 TO 35 MPH...INITIALLY ON
THE CAPROCK AND THEN SPREADING INTO THE ROLLING PLAINS THIS
AFTERNOON. ONGOING WIND ADVISORY REMAINS VALID. IN ADDITION...THE
GUSTY WINDS WILL ADVECT IN MUCH DRIER AIR AND LEAD TO A PERIOD OF
ELEVATED TO CRITICAL FIRE WEATHER THIS AFTERNOON...THOUGH THE
STATE OF THE FUELS SHOULD HELP MITIGATE THE OVERALL FIRE DANGER AND
THE ONGOING FIRE DANGER STATEMENT REMAINS VALID. WINDS WILL
DECREASE THIS EVENING...BUT THEY WILL BE REINVIGORATED EARLY
SUNDAY BEHIND A CANADIAN COLD FRONT.
&&
.PREV DISCUSSION... /ISSUED 558 AM CST SAT MAR 9 2013/
AVIATION...
AN ISOLATED SHOWER OR THUNDERSTORM MAY STILL DEVELOP AHEAD OF THE
PACIFIC FRONT THIS MORNING...BUT CHANCES ARE TOO LOW FOR MENTION
WITHIN EITHER THE KLBB OR KCDS TERMINALS. KCDS SHOULD SEE SOME
MVFR CEILINGS EARLY THIS MORNING BEFORE LIFTING BY MID MORNING.
SOUTH WINDS WILL INCREASE AND VEER FROM NEAR 12 KNOTS EARLY THIS
MORNING TO NEAR 30 KNOTS WITH GUSTS OF 40-45 KNOTS OUT OF THE WEST
BY LATE MORNING. BLOWING DUST SHOULD BE PREVALENT ENOUGH TO
PRODUCE MVFR VISIBILITIES AT KLBB FOR MUCH OF THE TIME LATER THIS
MORNING AND THIS AFTERNOON GIVEN THE LACK OF ANY RAINFALL LAST
NIGHT OR THIS MORNING. A LULL IN WINDS WILL TAKE PLACE AT BOTH
TERMINALS FROM SHORTLY AFTER SUNSET THROUGH AN HOUR OR TWO AFTER
MIDNIGHT...BEFORE A CANADIAN COLD FRONT MOVES IN FROM THE NORTH TO
RAMP NORTHWEST WINDS UP TO NEAR 20 KNOTS WITH GUSTS TO 30 KNOTS.
CLOUDS SHOULD BECOME REESTABLISHED AROUND FL030...BUT PREVAILING
CEILINGS ARE NOT FORECASTED AT THIS TIME.
PREV DISCUSSION... /ISSUED 449 AM CST SAT MAR 9 2013/
SHORT TERM...
DRYLINE HAS REMAINED STATIONED OVER EASTERN NEW MEXICO THIS MORNING
AS UPPER LOW CONTINUES SPINNING NEAR THE FOUR CORNERS REGION. EXPECT
THIS FEATURE AND ASSOCIATED LIFT TO PUSH QUICKLY EAST WITH SOME
ADDITIONAL SHOWER AND THUNDERSTORM ACTIVITY FORMING ALONG THE
ATTENDANT PACIFIC FRONT. BOUNDARY LAYER STABILIZATION WILL LIKELY
LIMIT THE SEVERITY OF ANY STORMS THAT DEVELOP...BUT ELEVATED
INSTABILITY OWING TO STEEPENING LAPSE RATES WILL NONETHELESS PROMOTE
THE THREAT OF SOME SMALL SIZED HAIL IF STORMS CAN BECOME
ESTABLISHED IN OUR REGION.
FOCUS WILL QUICKLY TURN TO DRIER AND WINDIER CONDITIONS IN WAKE OF
THIS LOW. AN INCREASING PRESSURE GRADIENT WILL DEVELOP AS THE UPPER
LOW PUSHES TOWARD WESTERN KANSAS AND CAUSES A SURFACE LOW TO DEEPEN.
WHILE THE 200 NAUTICAL MILE H70 HEIGHT GRADIENT HAS TRENDED DOWNWARD
TO NEAR 70 METERS...SUSTAINED SURFACE WINDS OF 30-35 MPH STILL LOOK
INEVITABLE...THUS WARRANTING A WIND ADVISORY FROM 16-00Z TODAY.
TROPOSPHERIC WIND MAXIMUMS WILL QUICKLY PUSH EAST THIS AFTERNOON
OVER THE ROLLING PLAINS...NEGATING HIGH WIND WARNING CRITERIA ON THE
FAVORED CAPROCK. BLOWING DUST WILL BE A CONCERN...ESPECIALLY ON THE
CAPROCK. HIGHER RAINFALL AMOUNTS AND COVERAGE LAST NIGHT AND THIS
MORNING WOULD HAVE LIMITED THIS POTENTIAL...BUT LOCATIONS SOUTHWEST
OF LUBBOCK GENERALLY ONLY PICKED UP A FEW HUNDREDTHS OF AN INCH.
AREAS AROUND PLAINVIEW TO LITTLEFIELD AND NORTHWEST RECEIVED A
QUARTER OF AN INCH WITH ISOLATED REPORTS UP TO NEAR HALF AN
INCH...BUT WIDESPREAD SIGNIFICANT RAIN BY AND LARGE WAS NOT THE RULE
AS SITES SOUTH AND EAST OF LUBBOCK REMAINED DRY.
A NORTHWEST TO SOUTHEAST GRADIENT IN TEMPERATURES WILL OCCUR THIS
AFTERNOON AS THE COOL NATURED PACIFIC FRONT PUSHES THROUGH...RANGING
FROM THE UPPER 50S ACROSS NORTHWEST ZONES TO MID 70S FOR THE
SOUTHEASTERN REACHES OF THE FORECAST AREA.
A CANADIAN FRONT WILL MOVE THROUGH TONIGHT FROM THE NORTHWEST AND KEEP
WINDS IN THE 15-25 MPH RANGE. COLD AIR ADVECTION WILL AID IN COOLING
OVERNIGHT LOWS INTO THE UPPER 20S TO MID 30S WEST OF THE
ESCARPMENT...WHILE AREAS TO THE EAST WILL ONLY BOTTOM OUT IN THE
UPPER 30S TO AROUND 40.
LONG TERM...
BY SUNDAY MORNING...THIS MORNING/S WEATHER MAKER SHOULD BE SITUATED
OVER THE CENTRAL PLAINS WITH A TROUGH TRAILING BACK TO THE BAJA
PENINSULA. A SUBTENDING LOBE WILL ROTATE AROUND THE BACK SIDE OF THE
LOW ON SUNDAY BRINGING A BIT OF REINFORCING ENERGY FOR A CANADIAN
FRONT DUE IN TONIGHT. NORTHWEST FLOW WILL THEN PERSIST FOR THE
REMAINDER OF THE EXTENDED THOUGH SLOWLY FLATTENING AS NEGATIVELY
TILTED RIDGE EXTENDS FROM THE DESERT SOUTHWEST INTO EXTREME WESTERN
CANADA.
AS FRONT PUSHES THROUGH EARLY SUNDAY...CONVECTION LOOKS TO BREAK
OUT TO OUR SOUTHEAST AND CONTINUE IN THAT DIRECTION. TO OUR
NORTH...SOME LIGHT WRAP-AROUND PRECIPITATION SHOULD BE ABLE TO GET
GOING ON THE WESTERN PERIPHERY OF THE UPPER LOW AND MAY MAKE IT AS
FAR SOUTH AS THE TEXAS PANHANDLE. STILL...WILL KEEP FORECAST DRY
FOR OUR CWFA. WINDS WILL BE QUITE STOUT ON SUNDAY BEHIND THE FRONT
WITH SPEEDS IN THE 20 TO 30 MPH RANGE. AFTER RETURN FLOW STARTS TO
GET GOING LATE MONDAY...NEXT WEAK FRONT WILL TRY TO MAKE IT INTO
THE NORTHWESTERN PANHANDLE TUESDAY MORNING AND AGAIN THURSDAY AND
SATURDAY MORNINGS WITH LITTLE TO SHOW OTHER THAN A WIND SHIFT. DRY
CONDITIONS TO PREVAIL WITH LOTS OF SUN FOR SPRING BREAK.
FIRE WEATHER...
MUCH DRIER AND WINDIER CONDITIONS BEHIND A PACIFIC FRONT WILL DROP
MINIMUM RELATIVE HUMIDITY VALUES INTO THE TEENS TO LOW 20S AREAWIDE.
PORTIONS OF THE SOUTHERN SOUTH PLAINS WILL DIP TO 15 PERCENT OR
BELOW ALONG WITH MUCH OF THE ROLLING PLAINS WHERE TEMPERATURES WILL
BE WARMER. WINDS WILL BE SUSTAINED AROUND 30 MPH WITH GUSTS OF 40-50
MPH. TEMPERATURES NOT TOO FAR ABOVE AVERAGE...A LACK OF DRY
FUELS...AND A QUICKLY EASTWARD MOVING MID LEVEL JET MAXIMUM SHOULD
PRECLUDE WIDESPREAD AND LONG DURATION RED FLAG MINUTES. WILL STILL
EXPERIENCE ELEVATED TO CRITICAL CONDITIONS THIS AFTERNOON...SO WILL
ISSUE A FIRE DANGER STATEMENT TO CONVEY THIS THREAT.
&&
.PRELIMINARY POINT TEMPS/POPS...
FRIONA 57 27 47 25 60 / 0 0 0 0 0
TULIA 60 31 45 23 61 / 10 0 0 0 0
PLAINVIEW 61 31 47 23 62 / 10 0 0 0 0
LEVELLAND 63 33 51 27 64 / 0 0 0 0 0
LUBBOCK 64 34 50 26 63 / 10 0 0 0 0
DENVER CITY 63 33 52 29 63 / 0 0 0 0 0
BROWNFIELD 65 35 52 28 64 / 10 0 0 0 0
CHILDRESS 70 37 50 29 60 / 10 0 0 0 0
SPUR 69 40 52 28 62 / 10 0 0 0 0
ASPERMONT 76 39 52 29 61 / 30 0 0 0 0
&&
.LUB WATCHES/WARNINGS/ADVISORIES...
WIND ADVISORY UNTIL 6 PM CST THIS EVENING FOR THE FOLLOWING
ZONES: TXZ021>044.
&&
$$
23/07