AREA FORECAST DISCUSSION...UPDATED
NWS MARQUETTE MI
1245 PM EST MON JAN 19 2009
UPDATED FOR 18Z AVIATION DISCUSSION
.UPDATE...
RADAR INDICATED LES CONTINUING TO BRUSH THE LAKE SUPERIOR SHORELINE
NEAR MARQUETTE WITH BANDS ALSO INTO THE WRN HALF OF ALGER COUNTY.
WEBCAMS SHOWED OCNL LOWER VSBY WITH HEAVIER SNOW SHOWERS.
HOWEVER...SNOW REMAINED FLUFFY WITH VERY HIGH SNOW/WATER RATIO ABOVE
30/1. KDLH RADAR AND SFC OBS ALSO SHOWED AREAS OF LIGHT SNOW FROM NE
MN THROUGH WRN LAKE SUPERIOR AND W UPPER MI INTO NW WI AHEAD OF A
SHORTWAVE TROUGH DROPPING SE FROM NW ONTARIO.
THE 12Z NAM AND LCL HIGH RES WRF/ARW SUGGEST THAT THE MOST FAVORABLE
LOW LEVEL CONV WILL PERSIST JUST EAST OF MARQUETTE. EVEN
THOUGH...RADAR TRENDS STILL WOULD KEEP OCNLY HEAVY SHSN ALONG THE
SHORELINES FROM MARQUETTE INTO HARVEY EXPECT SOME EASTWARD SHIFT
THIS AFTERNOON. SO...WILL KEEP MENTION OF SCT TO NMRS SHSN WITH
ADDITIONAL ACCUMULATION OF 1 TO 3 INCHES.
OVER THE WEST...SOME LAKE ENHANCEMENT WITH THE SHRTWV COULD BOOST
SNOW TOTALS TO A FEW INCHES. OTHERWISE...GIVEN ONLY WEAK TO MODERATE
DYNAMICS AND AMOUNT OF AVBL MOISTURE...MAINLY JUST LIGHT SNOW WITH
ACCUMULATIONS OF AN INCH OR LESS ARE EXPECTED.
&&
.SYNOPSIS...
08Z WATER VAPOR LOOP AND RUC 500MB HEIGHT ANALYSIS CONTINUES TO SHOW
A HIGHLY AMPLIFIED PATTERN OVER NORTH AMERICA...WITH VERY STRONG
RIDGING OVER THE WESTERN U.S. INTO SW CANADA AND TROUGHING COVERING
MUCH OF THE EAST HALF OF NORTH AMERICA. PATTERN LOOKS TO REMAIN
HIGHLY AMPLIFIED THROUGH AT LEAST THE SHORT TERM TOO...WITH A NEARLY
NORTH TO SOUTH 140 KT JET AT 200MB EXTENDING FROM THE NUNAVUT REGION
OF CANADA INTO WESTERN MN DIVING SOUTH. RIDING ALONG THIS JET IS A
FAIRLY POTENT SHRTWV JUST TO THE NE OF LAKE WINNIPEG. A LITTLE BIT
OF RIDGING IS OCCURRING AHEAD OF THIS SHRTWV AND IS APPROACHING
WESTERN LAKE SUPERIOR. SFC RIDGING IS ALSO NOTED UNDER THIS UPPER
RIDGE...WHICH SEPARATES LOW PRESSURE IN SE ONTARIO AND LOW PRESSURE
IN NE MANITOBA. ALSO AT THE SFC IS A TROUGH THAT EXTENDS FROM THE
LOW IN SE ONTARIO INTO THE KEWEENAW...SIMILAR TO LAST NIGHT AT THIS
TIME. NORTH FLOW BEHIND THE TROUGH...COMBINED WITH 850MB TEMPS
AROUND -15C PER 00Z RAOBS FROM INL...CWPL...GRB AND APX...IS
SUPPORTING NUMEROUS LAKE EFFECT SNOW SHOWERS OVER NORTH CENTRAL AND
FAR WESTERN UPPER MI. COMBINATION OF KMQT VAD WIND PROFILE AND 02Z
TAMDAR SOUNDING FROM SAW SHOWED A CLASSIC PROFILE FOR HIGH SNOW TO
WATER RATIO SNOW...WITH MUCH OF THE LAKE EFFECT CLOUD DEPTH
CONTAINED WITHIN THE DENDRITIC SNOW GROWTH ZONE. SNOW TO WATER
RATIOS HAVE BEEN RUNNING 50 TO 1 OR HIGHER AT THE OFFICE...OR IN
OTHER WORDS VERY FLUFFY. LUCE COUNTY IS DRY AND MOSTLY
CLEAR...THANKS TO THE NE FLOW DIRECTION. TEMPS AT ERY HAVE DROPPED
TO 5 ABOVE...BUT THE TYPICAL COLDER SPINCICH LAKE RAWS SITE IS AT
-4F. TO OUR NW...CLOUDS ARE SPREADING SOUTH OVER NW
ONTARIO...ASSOCIATED WITH THE SHRTWV NEAR LAKE WINNIPEG.
SNOWFALL AMOUNTS SO FAR AT THE OFFICE ARE RUNNING NEAR 5 INCHES
SINCE 7 PM LAST NIGHT. ALSO...BESSEMER HAS HAD 4 INCHES SINCE 6 PM
LAST NIGHT. SEE LSRMQT AND PNSMQT FOR MORE SNOWFALL REPORTS.
&&
.DISCUSSION...
TODAY...SHRTWV NEAR LAKE WINNIPEG IS PROGGED TO DROP SOUTH THROUGH
MN AND INTO IA BY 00Z WITH THE UPPER JET...HELPING TO MAINTAIN
TROUGHING OVER THE EASTERN U.S.. AS THIS SHRTWV DROPS
SOUTH...PRESSURE RISES BEHIND IT SHOULD HELP TO BRING THE TROUGH
THAT IS SITTING NEAR THE KEWEENAW SOUTHWARD. MODELS REFLECT THIS BY
SHOWING THE LOW LEVEL FLOW GOING FROM NW AT 12Z TO MORE NORTH OR NE
BY 00Z. THIS CHANGE IN WIND DIRECTION SHOULD KEEP ANY SPOT FROM
ACCUMULATING TOO MUCH SNOW...THOUGH THERE IS SOME CONCERN BASED ON
950MB CONVERGENCE FIELDS THAT LAKE EFFECT MAY STAY PUT IN THE AREA
ALONG THE MQT/ALGER COUNTY LINES FOR THE ENTIRE DAY. PROFILE AGAIN
IS VERY FAVORABLE FOR HIGH SNOW TO WATER RATIOS. WILL LEAVE THE
GOING WARNINGS FOR MQT/ALGER THROUGH 18Z...BUT THEY MAY NEED TO BE
EXTENDED IF THAT BAND DOES STAY PUT AND BOTH WARNINGS VERIFY BEFORE
THEN (WHICH COULD BE TRICKY). MAY NEED TO WATCH THE FAR WEST A
LITTLE FOR LAKE EFFECT...ESPECIALLY WITH ENHANCEMENT LIKELY BY THE
SHRTWV DROPPING SOUTH NEARBY. IN FACT...THERE SHOULD BE SOME LIGHT
SYNOPTIC SNOW CROSSING THE WESTERN U.P. THIS AFTN. HIGHS TODAY
SHOULD BE SIMILAR TO THOSE YESTERDAY...GIVEN 850MB TEMPS HOLDING
NEARLY STEADY AROUND -15C.
TONIGHT...RIDGING IS PROGGED TO BUILD IN BEHIND THE SHRTWV THAT
DROPPED INTO IA TODAY...WITH THE RIDGE AXIS EXPECTED TO BE LOCATED
NEAR THE NORTH END OF LAKE SUPERIOR BY 12Z TUE. AGAIN...THIS UPPER
RIDGE AXIS SHOULD BE ASSOCIATED WITH A SFC RIDGE AS WELL...MOVING
OVER LAKE SUPERIOR BY 12Z TUE. THE APPROACH OF THE RIDGE SUGGESTS
WIND FLOW MOSTLY NORTH TO NE...THOUGH THERE MAY BE A TENDENCY FOR
WINDS TO BACK TO THE NW...ESPECIALLY OVER THE WESTERN HALF OF THE
CWA LATE. 850MB TEMPS STILL REMAIN PLENTY COLD FOR LAKE EFFECT TO
OCCUR...AND WITH 950MB CONVERGENCE FIELDS HIGHLIGHTING THE HIGHER
TERRAIN OF THE NORTH CENTRAL U.P....FIGURE THE GREATEST SNOW WILL
OCCUR THERE. AGAIN...IT SHOULD BE QUITE FLUFFY WITH THE MAJORITY OF
THE LAKE EFFECT CLOUD AND LIFT IN THE DENDRITIC GROWTH ZONE. RIGHT
NOW HAVE PUT IN MARGINAL ADVISORY SNOWFALL AMOUNTS. WILL HOLD OFF
ISSUING AN ADVISORY AT THIS POINT...THOUGH...GIVEN CURRENT HEADLINES
OUT. THE FAR WESTERN U.P. COULD GET CLOSE TO AN ADVISORY AS
WELL...BUT FLOW TURNING ANTICYCLONIC THROUGH THE NIGHT WOULD SEEM TO
SUGGEST SUB ADVISORY SNOWFALL. ELSEWHERE...THE ONLY OTHER MAIN ITEM
TO NOTE IS TEMPS IN THE EASTERN U.P... N TO NE FLOW
DRAINING/DOWNSLOPING OFF NE ONTARIO WILL HELP TO KEEP SKIES MOSTLY
CLEAR THERE. WITH LOW PRECIPITABLE WATER...TEMPS SHOULD FALL WELL
BELOW GUIDANCE. FOLLOWED CLOSE TO LOCAL WRF-ARW RUN WHICH SHOWED
LOWS NEAR -10F NEAR THE LUCE/CHIPPEWA COUNTY LINES. TEMPS EXPECTED
TO BE MUCH WARMER FOR THE REST OF THE CWA WITH FLOW OFF THE LAKE AND
LAKE EFFECT CLOUDS.
TUE...WEAK UPPER RIDGE IS EXPECTED TO SHIFT SOUTH INTO UPPER MI...IN
RESPONSE TO A CLIPPER SHRTWV DROPPING DOWN THE TOP OF THE RIDGE
ACROSS NE MANITOBA INTO NW ONTARIO. THIS MOTION ALOFT WILL CAUSE THE
SFC RIDGE OVER LAKE SUPERIOR TO MOVE SOUTH OF UPPER MI...RESULTING
IN THE WIND FLOW BACKING WITH TIME. AS THE FLOW BACKS...WARMER AIR
GETS ADVECTED INTO THE CWA...WITH 850MB TEMPS RISING TO -2C WEST TO
-10C EAST BY 00Z WED. THIS WARM ADVECTION COMBINED WITH BACKING FLOW
WILL HELP TO NOT ONLY MARCH THE LAKE EFFECT OVER THE NORTH CENTRAL
U.P. EASTWARD WITH TIME...BUT ALSO DIMINISH THE LAKE EFFECT OVERALL.
NEXT CONCERN IS POSSIBILITY FOR SYNOPTIC SNOW OVER WESTERN UPPER MI
AS INDICATED BY THE REGIONAL CANADIAN AND LOCAL WRF-ARW RUN. THE
SOURCE OF THE SYNOPTIC SNOW IS WARM ADVECTION AHEAD OF THE CLIPPER
DROPPING DOWN. HOWEVER...ISENTROPIC LIFT PROGS SUGGEST THE AIRMASS
MIGHT BE TOO DRY...THEREFORE WILL HOLD OFF ON INCLUDING ANY POPS FOR
SYNOPTIC SNOW. HAVE BROUGHT IN MORE CLOUDS...THOUGH. THESE
CLOUDS...COMBINED WITH THE WARM ADVECTION ALOFT CREATING HIGHER
STABILITY MEANS IT MAY BE HARD TO WARM MUCH AT THE SFC. ENDED UP
LOWERING HIGHS JUST SLIGHTLY...BUT READINGS SHOULD STILL REACH THE
20 DEGREE MARK OVER MOST PLACES...EXCEPT THE FAR EAST WHICH IS
CLOSER TO SEMI-ARCTIC AIR FROM ONTARIO.
TUE NIGHT AND WED....MODELS ARE IN GOOD AGREEMENT TAKING THE CLIPPER
SHRTWV DOWN THROUGH NE ONTARIO TUE NIGHT...THEN CONTINUING SE INTO
PA BY 00Z THU. AS ALLUDED TO IN PREVIOUS FORECAST...COULD BE SOME
LIGHT SYNOPTIC SNOW CROSSING FROM THE KEWEENAW PENINSULA INTO THE
EASTERN CWA...ASSUMING ENOUGH MOISTENING CAN OCCUR. GIVEN THE
MOISTURE CONCERNS...HAVE KEPT POPS LOW AT THIS TIME. OTHERWISE...THE
MAIN CONCERN WITH THE CLIPPER IS LOW CLOUDS THAT DEVELOP UNDERNEATH
WARMING ALOFT AT 850MB. 900-925 MB RH PROGS FROM THE NAM...GFS AND
LOCAL WRF-ARW RUN ALL POINT TO A DEVELOPING STRATUS DECK THROUGH THE
NIGHT...IN THE WAKE OF A WARM FRONT ASSOCIATED WITH THE CLIPPER. A
COLD FRONT ASSOCIATED WITH THE CLIPPER DROPS IN ON WED...WITH THE
GFS AND NOW THE 06Z NAM TRYING TO SHOW SOME LIGHT QPF WITH IT. BASED
ON SOUNDINGS...HAVE TO ADMIT QPF SEEMS PRETTY HARD TO GET OUT OF THE
FRONT. HOWEVER...ASSUMING THE LOW CLOUD DECK DOES FORM...WHEREVER
FLOW IS UPSLOPING...FREEZING DRIZZLE COULD OCCUR. FOR NOW...HAVE NOT
MENTIONED FZDZ GIVEN HOW FAR OUT IT IS IN TIME...BUT IT IS SOMETHING
THAT FUTURE SHIFTS WILL NEED TO MONITOR. DID RAISE CLOUD COVER T
MOSTLY CLOUDY...THOUGH. WITH THESE INCREASED CLOUDS...AND WARMING
ALOFT...DECIDED TO LOWER HIGH TEMPS SOME. DID NOT GO AS LOW AS MET
GUIDANCE...BUT ITS READINGS OF MID 20S OVER THE CENTRAL U.P. ARE
CERTAINLY POSSIBLE. LOWS FOR TUE NIGHT SEEMED REASONABLE...AND ONLY
RAISED THEM ABOUT A DEGREE TO ACCOUNT FOR INCOMING CLOUDS.
BEYOND WED...UPPER RIDGE OVER SW CANADA IS PROGGED TO GET PUSHED
DOWN...WITH MODELS ACTUALLY SHOWING A FAIRLY STRONG HIGH BUILDING
OVER THE YUKON (IN THE 1050S MB RANGE). THERE ARE TWO
QUESTIONS...THE FIRST IS WHEN A SFC LOW ASSOCIATED WITH THE SHRTWVS
PUSHING THE RIDGE DOWN MOVE THROUGH...AND WHEN DOES THE YUKON HIGH
BEGIN BUILDING SOUTHWARD INTO THE PLAINS. THE 00Z ECMWF LOOKED TO BE
SLOWER THAN THE PREVIOUS FORECAST FOR BRING THE SFC LOW AND
ASSOCIATED PCPN INTO THE CWA FOR WED NIGHT AND THU. EVEN THE GFS
LOOKED TO BE SLOWER. THEREFORE...HAVE LOWERED POPS. THE ECMWF THEN
BREAKS OFF FROM THE 00Z GFS...SHOWING A SFC LOW OVER NRN WI AT 00Z
FRI HEADING OFF TO THE EAST...ALLOWING 850MB TEMPS TO PLUMMET DURING
THE DAY FRI. THE GFS IS NOT NEARLY AS QUICK. FOR NOW...DECIDED TO
LEAVE THE FORECAST ALONE FOR THU NIGHT/FRI...WHICH WOULD BE IN
AGREEMENT ANYWAY WITH THE ECMWF. EITHER WAY...BOTH THE GFS AND ECMWF
PAINT A COLD PICTURE TOWARDS THE WEEKEND...WITH 850MB TEMPS FALLING
BACK BELOW -20C. HOWEVER...AS STATED IN YESTERDAYS DISCUSSION...THE
AIRMASS IS NOT FORECAST TO BE NEARLY AS COLD AS THE ONE EXPERIENCED
LAST WEEK.
&&
.AVIATION (FOR THE 18Z TAF ISSUANCE)...
KSAW...CONVERGENT NORTHERLY THIS AFTERNOON AND TONIGHT WILL KEEP
OCNL MODERATE SNOW SHOWERS GOING WITH MVFR TO OCNL IFR CONDITIONS.
WINDS BACKING NW LATE TONIGHT AHEAD OF APPROACHING RDG FROM THE NRN
PLAINS WILL SHIFT HEAVIER LES BANDS EAST AND IMPROVE CONDITIONS TO
MVFR AGAIN.
KCMX...THE COMBINATION OF A SHORTWAVE TROUGH AND NRLY FLOW WILL
RESULT IN PERSISTENT LES WITH IFR CONDITIONS THIS AFTERNOON.
FLOW BACKING NW LATE TONIGHT AHEAD OF APPROACHING RDG WILL IMPROVE
CONDITIONS AGAIN TO MVFR IN WEAKER LES BANDS.
&&
.MARINE (FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)...
WINDS ARE EXPECTED TO STAY AT OR BELOW 25 KTS THROUGH MUCH OF THE
FCST PD WITH A COUPLE OF EXCEPTIONS. SOUTHWEST WINDS INCREASING TO
30 KT OVER THE WRN HALF OF LAKE SUPERIOR SHOULD RESULT IN MODERATE
FREEZING SPRAY TUESDAY NIGHT. THEN NORTH TO NORTHWEST WINDS TO 30
KTS IN THE WAKE OF A COLD FRONT WILL LIKELY RESULT IN HEAVY FREEZING
SPRAY THURSDAY NIGHT INTO FRIDAY.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
LAKE EFFECT SNOW WARNING UNTIL 1 PM EST THIS AFTERNOON FOR
MIZ005-006.
LAKE EFFECT SNOW WARNING UNTIL 7 AM EST /6 AM CST/ THIS MORNING
FOR MIZ002-009.
LAKE SUPERIOR...NONE.
LAKE MICHIGAN...NONE.
&&
$$
SYNOPSIS/DISCUSSION...AJ
AVIATION...VOSS
MARINE...VOSS
AREA FORECAST DISCUSSION
NWS DULUTH MN
959 PM CST MON JAN 19 2009
.UPDATE...
SPOTTERS REPORT 3-4 INCHES OF SNOW FROM THIS AFTERNOON INTO THIS
EVENING...WITH ANOTHER 2-4 INCHES POSSIBLE FOR THE REMAINDER OF
THE NIGHT.
THE ADVISORY FOR ASHLAND AND IRON COUNTIES LOOK GOOD.
SNOW CONTINUES OVER THE SNOWBELT REGION OF ASHLAND AND IRON
COUNTIES. THE 00Z NAM12 IS SLOWER BACKING THE WINDS TONIGHT...AND
HAS THEM NNE THROUGH 06Z...THEN THEY BACK BY 12Z TO
NORTHWEST...AND CONTINUE TO BACK THROUGH TUESDAY. 850MB TEMPS ARE
FORECAST TO BE A BIT WARMER COMPARED TO THE 18Z NAM12 RUN...AND
TAMDAR SOUNDINGS AROUND KCMX AND CYQT CONFIRM THE LATEST NAM RUN.
FETCH...INVERSION LEVELS ARE STILL FAVORABLE FOR LES TONIGHT. WE
SHOULD SEE THE LES QUICKLY DIMINISH ON TUESDAY AS THE WINDS BACK
AND WARMER AIR MOVES IN.
THERE IS A CONCERN WE COULD GET ENOUGH SNOW TO JUSTIFY A
WARNING...BUT WE`VE HAD SO MUCH SNOW ALREADY OVER THE PAST FEW
DAYS...AND WITH THE VEERING/BACKING WINDS OVER THE NEXT 9
HOURS...CHANCES FOR SUSTAINED HEAVY SNOW IN ONE AREA IS
DIMINISHED. WE WILL KEEP THE ADVISORY AS IS.
ELSEWHERE...CLOUDS HAVE DIMINISHED OVER PARTS OF NORTHERN
MINNESOTA. ANYWHERE THERE ARE CLOUDS...THERE IS LIGHT SNOW OR
FLURRIES. WE KEPT THE MENTION OF FLURRIES THROUGH EARLY MORNING FOR
MOST AREAS OUTSIDE OF THE SNOWBELT.
WE WILL AGAIN SEE QUITE VARIABLE LOW TEMPERATURES...AS SKIES CLEAR
FROM THE NORTH.
&&
.AVIATION...
AREAS OF MVFR CEILINGS WILL CONTINUE TONIGHT...ALONG WITH MVFR/IFR
VSBYS IN LIGHT SNOW.
&&
.PREV DISCUSSION... /ISSUED 552 PM CST MON JAN 19 2009/
DISCUSSION...
SNOW FROM LAKE EFFECT SNOW SHOWERS AS WELL AS FROM THE SHORTWAVE
THAT DROPPED THROUGH THE AREA...AMOUNTED TO 1 TO 3 INCHES TODAY
ACROSS ASHLAND AND IRON COUNTIES. SPOTTERS HAVE REPORTED HEAVY
SNOW YET THIS EVENING.
THE ENVIRONMENT FOR LAKE EFFECT SNOW BECOMES MORE FAVORABLE THIS
EVENING. THE MEAN WIND WAS NORTHERLY EARLY THIS EVENING...AND WILL
VEER TO THE NORTH-NORTHEAST BY 03Z...THEN GRADUALLY BACK TO THE
NORTH...AND FINALLY NORTHWEST BY 15Z TUE. THE INVERSION DEEPENS AS
WELL THIS EVENING...THEN DROPS BY 15Z. NAM12 FORECASTS 850MB TEMPS
OF -17 TO -18C THIS EVENING...WARMING TO -12C BY 12Z TUE...AND TO
-10C ALONG THE NORTH SHORE BY 12Z.
THE SNOW TODAY WAS AIDED BY A POTENT SHORTWAVE...AND ALTHOUGH THAT
IS PASSING SOUTH OF THE AREA NOW...THERE IS ANOTHER WEAKER WAVE
UPSTREAM...THAT WILL AID IN LIFT TONIGHT.
WE WILL LIKELY ISSUE A LAKE SNOW ADVISORY FOR ASHLAND AND IRON
COUNTIES FOR TONIGHT THROUGH ABOUT 14Z TUE.
&&
POINT TEMPS/POPS...
DLH 0 21 15 29 / 20 10 10 10
INL -4 26 15 28 / 20 10 20 20
BRD 3 26 15 32 / 20 10 10 10
HYR -4 22 14 30 / 20 10 10 10
ASX 4 22 16 32 / 50 40 10 10
&&
.DLH WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...LAKE EFFECT SNOW ADVISORY UNTIL 8 AM CST TUESDAY FOR ASHLAND-
IRON.
$$
MELDE
AREA FORECAST DISCUSSION...UPDATED
NWS NORTH PLATTE NE
1235 PM CST MON JAN 19 2009
.UPDATE...
AT 18Z DRIER AIR HAD WEDGE INTO SOUTHWEST NEBRASKA WITH RELATIVE
HUMIDITIES AROUND 15 PERCENT ACROSS CHASE COUNTY. THE RUC SOLUTION
SHOWS THE MUCH LOWER DEWPOINTS SPREADING EAST ALONG THE STATELINE
IN THE FAR SOUTHWEST WHICH APPEAR UNDERDONE. THEREFORE A RED FLAG
WARNING WILL BE ISSUED FOR FIRE WEATHER ZONES 210 AND 204 WITH THE
GREATEST RISK TO EXTEND ACROSS DEUEL COUNTY EAST TO HIGHWAY 61.
AFTER 5 PM WINDS SHOULD BEGIN TO DIMINISH AS TEMPERATURES FALL TO
REDUCE THE FIRE DANGER.
&&
.PREV DISCUSSION... /ISSUED 311 AM CST MON JAN 19 2009/
DISCUSSION...
MERIDIONAL FLOW CONTINUES FROM CANADIAN PRAIRIES DOWN INTO CENTRAL
PLAINS WITH EXTREMELY AMPLIFIED RIDGE PARKED OVER WESTERN CONUS INTO
NW TERRITORIES...WHERE TEMPERATURES LAST WEEK IN THE MINUS 45 DEGREE
RANGE ARE NOW AROUND 45. EASTERN CONUS PAYING FOR THE WARM AIR TO
THE WEST WITH DEEPLY CARVED OUT TROF EXTENDING FROM POLAR VORTEX
NEAR BAFFIN ISLAND WELL INTO THE GULF OF MEXICO. THIS STRONG
NORTHERLY FLOW HAD HELPED WINDS INCREASE TO ADVY CRIT PAST FEW DAYS
AND EXPECT THE SAME TODAY WITH STEEP LLVL LAPSE RATES WITH WEAK CAA
HELPING TO BRING WINDS DOWN. GUIDANCE HINTING AT THIS THE PAST FEW
DAYS AND WILL COVER WHOLE OF CWA THROUGH SUNSET. TEMPS A BIT TRICKY
WITH CAA THIS AFTERNOON AND POSSIBILITY OF LINGERING CLOUDS ACROSS
PORTIONS OF NORTHEAST CWA. GOES DPI SHOWING MOISTURE PLUME ROUNDING
WESTERN RIDGE AND DROPPING ACROSS CENTRAL CONUS WHERE STRATUS DECK
HAS FORMED ALONG ARCTIC SFC BOUNDARY. WATER VAPOR ALSO SHOWING NEXT
IMPULSE RAPIDLY DROPPING SOUTHWARD ACROSS MANITOBA AND WILL PUSH
WEAK FRONT THROUGH CWA TODAY AND ALLOW THE ARCTIC FRONT TO WAVER
BACK INTO NORTHEAST NEB THIS AFTERNOON. PAST FEW FORECASTS HAVE
ENDED UP TO COOL AND WENT TOWARD THE WARMER GUIDANCE TODAY...BUT
THIS MAY NOT PAN OUT IN FAR NORTHEAST IF CLOUDS PERSIST INTO
AFTERNOON AND STRONGER GFS SOLN VERIFIES WITH STRONGER CAA. SHOULD
STILL SEE TEMPS NEAR 60 IN THE FAR SOUTHWEST WHICH WILL CONTINUE TO
CREATE VERY HIGH FIRE DANGER WITH RH LEVEL APPROACHING CRITICAL
LEVELS AND STRONG WINDS. TUESDAY AND WEDNESDAY LOOKS TO TAKE A BREAK
FROM THE WINDS AND RIDGE TRANSLATES ENOUGH TO PUSH CORE OF WINDS TO
THE EAST. TEMPS SHOULD BE WELL ABOVE NORMAL WTH READINGS IN THE
LOWER 50S TO POSSIBLY THE UPPER 60S IN THE FAR SOUTHWEST. AGAIN THIS
WILL EXACERBATE THE FIRE WEATHER CONDITIONS THE LIGHTER WINDS WILL
OFFSET THE POSSIBILITY OF LOWER RH LEVELS. BIGGEST CHANGE LOOKS TO
BE ON THURSDAY WITH MODEL AGREEMENT OF SLOWER ARRIVAL OF COLD AIR
AND HAVE WARMED UP THURSDAY AND DELAYED POPS UNTIL FRIDAY.
AVIATION...
SHORT RANGE FORECAST MODELS SHOW LOW CEILINGS OVER NORTH CENTRAL
NEBRASKA NORTH AND EAST OF AN ANW-BBW LINE. CEILINGS BELOW
INSTRUMENT THRESHOLDS ARE POSSIBLE. HOWEVER...THE LOWER CEILINGS ARE
NOT LIKELY TO REACH AS FAR WEST AS VTN AND LBF...SO THE TERMINAL
FORECASTS DO NOT REFLECT IT.
AS YESTERDAY...WIND IS EXPECTED TO BE STRONG WITH 320-350 AT
25-35KT. THERE IS SOME POTENTIAL FOR CROSS WIND EXCEEDING THE
THRESHOLDS FOR SMALL GENERAL AVIATION AND ROTARY WING AIRCRAFT...BUT
THEY SHOULD STAY BELOW 20KTS CROSS WIND COMPONENT FOR AIRFIELDS WITH
NORTHWEST-SOUTHEAST ORIENTED RUNWAYS. CURRENT INDICATIONS ARE THAT
THE WIND INCREASES UNIFORMLY FROM THE SURFACE TO 2000 FT AGL WITH UP
TO 50KT IN THE 1800-2000 FT LAYER...SO SIGNIFICANT LOW LEVEL WIND
SHEAR IS NOT EXPECTED.
FIRE WEATHER...
LOWEST RELATIVE HUMIDITY TODAY MAY BRIEFLY APPROACH 15 PERCENT
IN THE IMPERIAL AREA...BUT FOR THE SOUTHEAST PANHANDLE AND SOUTHWEST
NEBRASKA...IT SHOULD STAY IN THE 15-20 PERCENT RANGE. NORTHWEST WIND
IS LIKELY TO INCREASE TO 25-35 MPH IN FREQUENT GUSTS LATE MORNING
THROUGH LATE AFTERNOON...SO THE WIND WILL BE ABOVE CRITICAL
THRESHOLDS OF FIRE DANGER. FOR NOW...IT APPEARS THAT THE WIND WILL
BE THE ONLY CRITICAL THRESHOLDS AND WE WILL NOT ISSUE ANY FIRE
HEADLINES. IT WILL NEED TO BE WATCHED THOUGH. MUCH LOWER RELATIVE
HUMIDITY IS LIKELY TUESDAY AND WEDNESDAY...BUT THE WIND WILL BE WELL
BELOW CRITICAL THRESHOLDS. WE WILL CONTINUE TO INCLUDE VERY HIGH
FIRE DANGER IN THE HAZARDOUS WEATHER OUTLOOK
&&
.LBF WATCHES/WARNINGS/ADVISORIES...RED FLAG WARNING UNTIL 6 PM CST /5 PM MST/ THIS AFTERNOON FOR
NEZ204 AND 210.
WIND ADVISORY UNTIL 6 PM CST /5 PM MST/ THIS AFTERNOON FOR
NEZ004>010-022>029-035>038-056>059-069>071-094.
&&
$$
FIRE WEATHER...KECK
AREA FORECAST DISCUSSION
NWS NORTH PLATTE NE
323 AM CST SUN JAN 18 2009
.DISCUSSION...
STRONG NORTHERLY FLOW REMAIN IN PLACE IN MID LEVELS THANKS TO HIGHLY
AMPLIFIED RIDGE ALONG WEST COAST AND DEEP TROF ACROSS THE EASTERN
CONUS. CENTRAL PLAINS RIGHT ON THE CUSP BETWEEN TWO INFLUENCES WITH
COLD AIR IN PLACE FROM MN TO JUST EAST OF MO RIVER AND WARMER AIR
ALONG FRONT RANGE IN THE HIGH PLAINS. THIS SHOULD KEEP LARGE SPREAD
ACROSS LBF CWA TODAY WITH LOWER 40S EXPECTED AGAIN ACROSS FAR
NORTHEAST TO NEAR 60 IN THE FAR SOUTHWEST. FLOW IS EXTREMELY DRY
WITH ONLY HIGH LEVEL MOISTURE DROPPING DOWN BACK SIDE OF RIDGE IN
FORM OF CIRRUS. MAIN CONCERN TODAY AND PROBABLY AGAIN ON MONDAY WILL
BE WINDS ACROSS WESTERN 2/3 OF CWA. WARMING LLVL TEMPS WITH WEAK
WAVE DROPPING THROUGH THE FLOW WILL INCREASE LAPSE RATES AND
UNIDIRECTIONAL FLOW SHOULD ALLOW GOOD MIXING WITH BUFKIT SHOWING
LOWER END ADVISORY WINDS ALONG AND WEST OF HIGHWAY 183. NO SLAM DUNK
BUT A FEW PLACES SHOULD BE SUSTAINED AOA 30MPH FROM LATE MORNING
INTO THE MID AFTERNOON. MERIDIONAL FLOW CONTINUES ACROSS PLAINS INTO
MONDAY AS RIDGE BUILDS SLIGHTLY WESTWARD WITH APPROACHING E.PAC
SYSTEM AND CHANNELIZED ENERGY CONTINUES TO KEEP TROF CARVED ACROSS
EASTERN CONUS INTO GULF. NAM/GFS DIFFERING SOMEWHAT WITH STRONGER
ENERGY ROTATING THROUGH W.GREAT LAKES INTO LOWER MO VALLEY ON MONDAY
WITH GFS SHOWING QUICKER AND STRONGER WAVE MOVING THROUGH MID DAY.
AS A RESULT COLDER AIR IS FILTERING INTO NE CWA DURING THE
AFTERNOON. NAM NOT AS ROBUST WITH WAVE AND WITH FROPA COLD AIR NOT
AS AGRESSIVE. IMPACT SEEMS SMALL ATTM AND HAVE KEPT TEMPS NEAR
PERSISTANCE WITH LOWER 40S NORTHEAST AND MID 60S FAR SOUTHWEST. FIRE
CONCERNS WILL ALSO BE RESULT OF THIS DRY AND WARM WEATHER...THOUGH
ATTM CRITCAL LEVELS LOOK TO BE JUST OUT OF REACH...BUT CONTINUE TO
BE MONITORED...ESPECIALLY FOR TUESDAY AS RIDGE BREAKS DOWN AND DRIER
AIR MOST LIKELY TO REACH FARTHER INTO WESTERN CWA. WEDNESDAY WILL BE
TRANSITIONAL DAY WITH TEMPS STILL ABOVE NORMAL IN MAINLY ZONAL FLOW
ON NORTHERN PERIPHERY OF FLATTENED RIDGE...BUT WITH ENERGY FROM
EASTERN CONUS TROF ROTATING INTO W.ATLANTIC HUDSON BAY LOW BECOME
MORE ESTABLISHED AND BEGIN TO THROW COLD AIR BACK FROM HIGH LATS
INTO CENTRAL PLAINS...WITH COLDER ENDING TO THE WEEK INTO NEXT
WEEKEND.
&&
.AVIATION...
VISUAL FLIGHT RULES WILL CONTINUE THROUGH AT LEAST 18Z IN
WESTERN AND NORTH CENTRAL NEBRASKA. LATER IN THE AFTERNOON TO EARLY
EVENING SOME MARGINAL CEILINGS ARE LIKELY OVER THE EASTERN THIRD OF
NEBRASKA WITH THE FRONT. HOWEVER...THERE IS CONSIDERABLE UNCERTAINTY
OVER WHETHER OR NOT IT WILL REACH VALENTINE AND VIRTUALLY NO CHANCE
OF IT REACHING NORTH PLATTE.
WIND IS EXPECTED TO HAVE SIGNIFICANT IMPACT ON AREA AIRPORTS.
ONCE AGAIN...AS WAS THE CASE YESTERDAY...CROSSWINDS ARE NOT LIKELY
TO BE A MAJOR ISSUE FOR THE MEDIUM SIZED AIRCRAFT AT NORTH PLATTE
SINCE THE DIRECTION IS OFF ONLY ABOUT 30 DEGREES FROM THE PRIMARY
RUNWAY CONFIGURATION THERE. HOWEVER...LOW LEVEL WIND SHEAR IS LIKELY
TO BE PRESENT IN NORTH PLATTE EARLY THIS MORNING AS SURFACE WIND IN
THE VALLEY IS EXPECTED TO BE 10KT OR LOWER WITH INCREASE TO 45-50KT
WITHIN 2000 FEET AGL. AS THE NEAR SURFACE LAYER MIXES...WIND OVER
WESTERN AND NORTH CENTRAL NEBRASKA IS EXPECTED TO BECOME 330-360 AT
25-35KT.
&&
.FIRE WEATHER...
THE WIND OVER WESTERN AND NORTH CENTRAL NEBRASKA IS EXPECTED TO
INCREASE TO CRITICAL THRESHOLDS TODAY AND MONDAY. HOWEVER...THE
LOWEST RELATIVE HUMIDITY IS EXPECTED TO BE IN THE SOUTHWEST AND
ABOUT 20 PERCENT WHICH IS HIGHER THAN CRITICAL THRESHOLDS. THE
HUMIDITY IS MORE LIKELY TO APPROACH 15 PERCENT IN THE PANHANDLE AND
SOUTHWEST TUESDAY AND WEDNESDAY...BUT THE WIND IS EXPECTED TO REMAIN
BELOW THE CRITICAL THRESHOLD OF 25 MPH. THE BOTTOM LINE IS THAT...AT
THIS TIME...WE ARE NOT EXPECTING TO NEED ANY FIRE WEATHER HEADLINES.
WE WILL...HOWEVER...MENTION HIGH FIRE DANGER FOR THE PANHANDLE AND
SOUTHWEST IN THE HAZARDOUS WEATHER OUTLOOK FOR TODAY THROUGH
WEDNESDAY.
&&
.LBF WATCHES/WARNINGS/ADVISORIES...WIND ADVISORY FROM 10 AM CST THIS
MORNING TO 6 PM CST THIS AFTERNOON FOR
NEZ004>006-008-009-022>027-035>038-056>059-069>071-094.
&&
$$
13/SPRINGER
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
1010 AM EST SUN JAN 18 2009
.SYNOPSIS...
A COLD FRONT WILL BRING RAIN TO THE AREA TODAY TAPERING OFF THIS
EVENING. A COUPLE OF STRONG MID LEVEL SYSTEMS WILL MOVE ACROSS THE
REGION MONDAY AND TUESDAY. THESE WILL BRING COLD TEMPERATURES TO
THE AREA THROUGH MIDWEEK. A SLOW WARMING TREND SHOULD TAKE PLACE
LATER IN THE WEEK AS HIGH PRESSURE MOVES OFF THE COAST. A FRONT
MAY BRING ANOTHER CHANCE OF SHOWERS NEXT WEEKEND.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 10 AM SUNDAY...
ALL MENTION OF NON-LIQUID PRECIP HAS BEEN REMOVED AS DEWPOINTS HAVE
RISEN ABV FREEZING ALL LOCATIONS. SINCE THE FASTER TIMING FOR PRECIP
ARRIVAL FROM YDY`S GUIDANCE HAS COME TO PASS THE AFTERNOON SHOULD
END UP ON THE COOL SIDE OF MOS. HAVE TRIMMED NUMBERS BACK A BIT TO
KEEP ALL LOCATIONS IN THE 40S...LOW/MID INLAND AND MID/UPPER COAST.
ANY WAA TODAY WILL BE NULLIFIED BY THE EXTENSIVE CLOUDS AND PRECIP.
&&
.SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/...
AS OF 3 AM SUNDAY...THE RELENTLESS BARRAGE OF SHORT WAVES EMBEDDED
IN THE MEAN NORTHWEST FLOW WILL CONTINUE WITH FEATURES BOTH MONDAY
AND TUESDAY AFTERNOON. WITH THIS TYPE OF SYNOPTIC SITUATION IT IS
PRUDENT EVEN THIS FAR SOUTH TO INTERROGATE SOUNDINGS FOR THE
POSSIBILITY OF FROZEN PRECIPITATION. AS FOR THE FIRST SYSTEM...BOTH
THE NAM AND GFS ARE GENERATING OUT A COUPLE OF HUNDREDTHS OF QPF
ACROSS OUR AREA WITH THE NAM A BIT FURTHER NORTH WITH ITS VERSION.
MODEL SOUNDINGS SHOW AN INVERTED-V SIGNATURE INDICATIVE OF THE VERY
DRY AIR MASS AT THE SURFACE. THIS SHOULD PRECLUDE ANY MEASURABLE
PRECIPITATION MONDAY AFTERNOON ALTHOUGH THERE COULD BE A SPRINKLE
AND VIRGA IS ALMOST ASSURED. SURFACE TEMPERATURES SHOULD BE JUST
WARM ENOUGH TO KEEP ANY SPRINKLES OF THE LIQUID VARIETY. ANY
ACTIVITY THAT COULD PERSIST INTO MONDAY EVENING COULD REACH THE
GROUND AS AN ICE PELLET OR WET SNOWFLAKE AS THE BOUNDARY LAYER COOLS
JUST ENOUGH. BUT ONCE AGAIN...DO NOT EXPECT ANYTHING MEASURABLE.
ANOTHER SHORT WAVE DIVES WELL SOUTH OF THE AREA TUESDAY. THE STORY
WITH FEATURE WILL BE THE COLD AIR. STRONG COLD AIR ADVECTION
BASICALLY ALL DAY TUESDAY WARRANTS UNDERCUTTING GUIDANCE FOR
HIGHS...AND IT WILL CERTAINLY NOT SURPRISE ME IF MOST STATIONS SEE
ANOTHER DAY OF HIGHS IN THE 30S. WEDNESDAY MORNING WILL SEE
WIDESPREAD LOW TO MID 20S...ALTHOUGH A STEADY BREEZE AT THE SURFACE
WILL KEEP TEMPERATURES FROM DROPPING INTO THE TEENS MOST PLACES.
&&
.LONG TERM /WEDNESDAY THROUGH SATURDAY/...
AS OF 3 AM SUNDAY...MEDIUM AND LONG RANGE MODELS CONTINUE TO
ADVERTISE THE PERSISTENT EAST COAST TROUGH RELAXING BY THE
WEEKEND. THIS SHOULD ALLOW A WEAK SYSTEM TO MOVE ACROSS LATE
FRIDAY OR EARLY SATURDAY AND MORE IMPORTANTLY...A WARMING TREND TO
COMMENCE WITH THE LATEST MEX NUMBERS ADVERTISING NUMBERS ABOVE
CLIMATOLOGY. WILL WAIT FOR MORE CONSISTENCY BEFORE TEASING THE
PUBLIC WITH HIGHS IN THE 60S FRIDAY AND SATURDAY...BUT WITH THE
PATTERN CHANGE IT IS DOABLE.
&&
.AVIATION /12Z SUNDAY THROUGH THURSDAY/...
VFR AT ALL TERMINALS AT 12Z. AS PRECIPITATION CONTINUES TO INCREASE
THROUGH THE MORNING LOW LEVELS WILL CONTINUE TO BECOME MORE
SATURATED. THERE WILL BE A SLIGHT CHANCE OF SOME SLEET/SNOW MIXED
IN WITH THE RAIN EARLY THIS MORNING BUT IT SHOULD NOT AFFECT
AIRCRAFT OPERATIONS. CEILINGS WILL LOWER TO MVFR BY LATE MORNING
AT FLO/LBT AND BY AFTERNOON AT THE COASTAL TERMINALS. THERE WILL
BE A SLIGHT CHANCE OF IFR VISIBILITIES AT FLO/LBT AFTER 16Z AS
RAIN INCREASES AND BR BEGINS TO DEVELOP.
THIS AFTERNOON IFR CEILINGS EXPECTED TO DEVELOP AT FLO/LBT AND BY
THIS EVENING AT THE COASTAL TERMINALS. SOME IFR VISIBILITIES WILL
ALSO OCCUR AT FLO/LBT THIS AFTERNOON AS PRECIPITATION PEAKS. THE
PRECIPITATION ENDS BY THIS EVENING BUT IFR CEILINGS WILL LIKELY
CONTINUE OVERNIGHT AS MOISTURE WILL BE TRAPPED BENEATH A LOW LEVEL
INVERSION.
EXTENDED OUTLOOK THROUGH THURSDAY...IFR CONDITIONS POSSIBLE EARLY
MONDAY.
&&
.MARINE...
NEAR TERM /THROUGH TONIGHT/...
AS OF 10 AM SUN...
WNA GUIDANCE FROM 06Z CONTINUES TO SHOW THAT SOME 6 FT SEAS MAY
AFFECT THE OUTER WATERS MAINLY NEAR FRYING PAN SHOALS. THIS MODEL IS
GFS-BASED HOWEVER AND IT HAS BEEN THE CONSENSUS FOR SOME TIME THAT
IT IS TOO AGGRESSIVE WITH WINDS. 12Z WRF IS A BIT STRONGER HOWEVER
THAN PREV RUNS. HAVE BUMPED UP WINDS EVER SO SLIGHTLY AND SEAS AS
WELL. MAY NEED A BRIEF PD OF SCEC FOR NRN TWO ZONES.
SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/...
AS OF 3 AM SUNDAY...WILL SEE A WESTERLY FLOW INITIALLY ACROSS THE
WATERS AS ONE SYSTEM DEPARTS BACKING SLIGHTLY TO SOUTHWEST MONDAY
AFTERNOON AS ANOTHER SHORT WAVE AND ASSOCIATED COLD FRONT MOVES
ACROSS. THE STRONGEST WINDS WILL OCCUR IN THE WAKE OF THIS SYSTEM
LATE MONDAY INTO TUESDAY MORNING AND THIS WILL BE THE NEXT CHANCE
FOR SMALL CRAFT CONDITIONS. TUESDAY WILL FEATURE STRONG COLD AIR
ADVECTION ALTHOUGH WITH THE SECOND SHORT WAVE DROPPING FURTHER
SOUTH...THE LOW LEVEL WIND FIELDS ARE NOT THAT STRONG...AND A
NORTHWEST FLOW OF 15-20 KNOTS SHOULD PERSIST THROUGH WEDNESDAY
MORNING.
WITH WINDS MAINTAINING AN OFFSHORE COMPONENT THROUGH THE
PERIOD...SEAS WILL REMAIN IN A 2-4 FOOT RANGE THE THE POSSIBILITY OF
SOME FIVE FOOTERS IN AMZ252 EARLY TUESDAY.
LONG TERM /WEDNESDAY THROUGH THURSDAY/...
AS OF 3 AM SUNDAY...NO CHANGES TO THE EXTENDED PART OF THE COASTAL
WATERS FORECAST THIS MORNING. MARINERS CAN STILL EXPECT A
CONDITIONS TO RELAX CONSIDERABLY WITH WINDS DROPPING BELOW 15 KNOTS
AND SEAS OF 2-3 FEET AS THE AXIS OF HIGH PRESSURE DRIFTS ACROSS.
&&
.ILM WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
NC...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...SHK
NEAR TERM...MBB
SHORT TERM...SHK
LONG TERM...SHK
AVIATION...MRR
AREA FORECAST DISCUSSION
NWS RALEIGH NC
950 AM EST SUN JAN 18 2009
.SYNOPSIS...AN UPPER LEVEL DISTURBANCE WILL MOVE EAST ACROSS THE
REGION LATER TODAY. A STRONGER UPPER LEVEL DISTURBANCE WILL MOVE
THROUGH THE REGION MONDAY AND TUESDAY...PUSHING A COLD FRONT
THROUGH THE AREA ON MONDAY. AN AREA OF LOW PRESSURE WILL DEVELOP
ALONG THE FRONT AS IT MOVES OFFSHORE MONDAY NIGHT AND TUESDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 945 AM SUNDAY...
RECENTLY UPDATED FORECAST/GRIDS TO ACCOUNT FOR EXPANSION OF PRECIP
ACROSS THE EASTERN PIEDMONT AN SANDHILLS. STRONG SPEED CONVERGENCE
BETWEEN 925-850MB ACROSS THE REGION ACCOUNTING FOR THE NORTHEAST
EXPANSION OF THE PRECIP INTO CENTRAL NC. OBSERVED A LITTLE SLEET
MIXED WITH THE RAIN HERE AT THE OFFICE AND A STORM SPOTTER IN NORTH
RALEIGH AT 915 AM REPORTED MAINLY LIGHT SNOW MIXED WITH
SLEET...CREATING A LIGHT DUSTING ON THE DECK. AN ACARS AIRCRAFT
SOUNDING FROM GSO AT 1355Z INDICATED A MINUTE WARM NOSE AT 805MB
THEN A COLDER LAYER BELOW TO MINUS 3 BELOW BEFORE WARMING TO NEAR
FREEZING AT THE SURFACE. THUS ANY PRECIP THROUGH 17Z IN THE NORTHERN
PIEDMONT INTO THE FAR NORTHERN COASTAL PLAIN WILL LIKELY CONTAIN A
WINTRY MIX OF RAIN/SLEET/SNOW. BY 17-18Z...SLY FLOW WILL PULL ENOUGH
WARM AIR INTO THE LOWEST 5000FT TO CHANGE ALL PRECIP TO RAIN. TEMPS
ARE WARMING A LITTLE FASTER THAN EARLIER THOUGHT SO HAVE ADJUSTED
HOURLY TEMP GRIDS TO ACCOUNT FOR THIS. HOWEVER OVERCAST SKIES AND
PATCHES OF LIGHT PRECIP SHOULD PREVENT TEMPS FROM CLIMBING ABOVE
FORECAST MAX TEMPS.
CAVEAT FOR LATER THIS MORNING AND THIS AFTERNOON WILL BE THE NW
PIEDMONT INCLUDING THE TRIAD REGION. STILL APPEARS THAT BULK OF
MOISTURE AND LIFT WILL OCCUR EAST AND SOUTHEAST OF THIS REGION. IF
PRECIP SHIELD WERE TO EXPAND TO THE NW...THE LOWER DEWPOINTS IN THE
NW PIEDMONT WOULD ENHANCE EVAPORATIVE COOLING...LEADING TO A PERIOD
OF LIGHT SNOW/SLEET BEFORE BECOMING A MIX OF RAIN AND SNOW. RADAR
TRENDS TO OUR SW ACROSS UPSTATE SC SUGGEST THAT PRECIP
MOVING/EXPANDING MORE TO THE E RATHER THAN N-NE. THUS APPEARS THAT
PROBABILITY OF MEASURABLE PRECIP IN THE NW PIEDMONT STILL AROUND
20%. WILL CONTINUE TO MONITOR.
BULK OF PRECIP WILL DIMINISH BETWEEN 23Z-03Z AS BEST UPPER LEVEL
SUPPORT LIFTS NE. EXPECT SKIES TO REMAIN OVERCAST OVERNIGHT AS MID
LEVEL INVERSION TRAPS LOW LEVEL MOISTURE. THIS SHOULD RESULT IN
OVERNIGHT TEMPS NOT AS COLD AS RECENT NIGHTS. RAISED MIN TEMPS A
COUPLE OF DEGREES FROM EARLIER FORECAST.
&&
.SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/...
AS OF 300 AM SUNDAY...
MONDAY... ANOTHER VORT MAX MOVING ACROSS THE AREA WITH COLD
NORTHWEST FLOW AND GOOD LOW LEVEL MOIST WILL RESULT IN CHANCE OF
PRECIPITATION. NAM/WRF MODEL SOUNDINGS SHOW SUFFICIENT LIFT AND
MOISTURE IN THE CRITICAL -12 TO -15C DENDRITIC GROWTH
LAYER...SUPPORTING SNOW ACROSS THE NORTHERN TIER. MODEL QPF IS
SPITTING OUT AROUND 0.10" OF AN INCH. GIVEN NWLY EVENT...HIGH SNOW
TO LIQUID RATIO OF 15 TO 20:1 COULD PRODUCE A DUSTING OF 1 TO 1.5
INCHES...BELOW ADVISORY CRITERIA. WILL KEEP POPS IN THE 30 TO 40
PERCENT RANGE ACROSS THE NORTHERN PIEDMONT. HIGHS WILL RANGE FROM
THE MID 30S NORTH TO MID 40S SOUTH.
MONDAY NIGHT AND TUESDAY...
AS THE AMPLIFIED LONG WAVE TROUGH DIGS FURTHER SOUTH INTO THE
SOUTHEAST US...NWP MODEL GUIDANCE DIVERGE WITH WHICH VIGOROUS
VORTMAX WILL PRODUCE SUFFICIENT LIFT AND MOISTURE ACROSS NORTH
CAROLINA...AS THE LAST VORT ENERGY IS PROGGED TO MOVE THROUGH THE
AREA LATE MONDAY AND INTO TUESDAY.
VERY DIFFICULT TO DETERMINE BEST COURSE OF ACTION FOR MONDAY NIGHT
THROUGH TUESDAY...AS ONE IS FACED WITH THE CHALLENGE OF LEANING
TOWARDS OVERALL MODEL CONSENSUS(GFS/NAM/ENSEMBLE)...OR THE OUTLIER
...THE EC WHICH HAS PERFORMED/VERIFIED BETTER OVER THE PAST FEW
MONTH...BUT CURRENTLY LACKS RUN-TO-RUN CONTINUITY.
THE LATEST 00Z/18 EC NOW INDICATES A SLOWER MORE AMPLIFIED UPPER
TROUGH AND VORT PASSAGE ON TUESDAY...INDUCING CYCLOGENESIS CLOSER
TO THE CAROLINA COAST TUESDAY MORNING. THE RESULT IS A THIRD OF AN
INCH OF LIQUID QPF ACROSS THE SOUTHERN TIER TUESDAY MORNING...
PRODUCING ANOTHER 0.10" ACROSS THE COASTAL PLAINS AS THE SYSTEM
SHIFTS FURTHER OFFSHORE...ALONG THE 850 CYCLONIC CIRCULATION CENTER.
MODEL PARTIAL THICKNESSES INDICATE ENTIRE LAYER IS BELOW FREEZING...
SUPPORTING SNOW CHANCES ACROSS THE SOUTHERN PIEDMONT...SANDHILLS AND
COASTAL PLAIN REGIONS ON TUESDAY. HOWEVER CONFIDENCE IS LOW
CONSIDERING HOW THE EC HAS WAVERED BACK AND FORTH OVER THE PAST FEW
MODEL RUNS. WILL KEEP FORECAST DRY FOR NOW...BUT WILL CONTINUE TO
MONITOR NEW MODEL UPDATES FOR BETTER MODEL CONSENSUS AND/OR BETTER
EC CONTINUITY. LOWS MONDAY NIGHT IN THE LOWER 20S NORTH TO MID 20S
SOUTHEAST. THICKNESSES SUPPORT HIGHS IN THE LOWER 30S NORTH...TO
LOWER TO MID 30S SOUTH. WILL TREND TOWARDS TO COOLER MET GUIDANCE.
HIGHS IN THE MID TO UPPER 30S.
&&
.LONG TERM /WEDNESDAY THROUGH SATURDAY/...
AS OF 300 AM SUNDAY...
NWP MODELS CONTINUE TO INDICATE A CHANGE IN THE UPPER AIR PATTERN AS
PACIFIC SHORTWAVE ENERGY IS EXPECTED TO MOVE ONSHORE WEDNESDAY...
EFFECTIVELY DISMANTLING THE UPPER RIDGE OVER THE WESTERN U.S. THIS
WILL IN TURN CAUSE L/W TROUGH ALONG THE EASTERN SEABOARD TO LIFT NE
AND BACK UPPER LEVEL FLOW TO MORE OF A ZONAL PATTERN THU INTO FRI
OVER OUR AREA. THIS WILL SIGNAL THE BEGINNING OF A MODEST WARMING
TREND. SHOULD SEE TEMPS RETURN TO NEAR OR ABOVE NORMAL LEVELS BY
THURSDAY. ON SATURDAY...A SPLIT FLOW OCCURS AS UPPER LEVEL LOW MOVES
ONSHORE OF CENTRAL/SOUTHERN CA. WHILE MAIN STORM TRACK WILL REMAIN
WELL NORTH OF CENTRAL NC. MINOR DISTURBANCE IN THE WEAK SOUTHERN
STREAM WILL HAVE THE POTENTIAL TO ENHANCE MOISTURE TRANSPORT INTO
CENTRAL NC...RESULTING IN INCREASE CLOUD COVERAGE FRI NIGHT INTO
SATURDAY WITH THE POSSIBILITY OF SOME LIGHT PRECIP ON SATURDAY.
SINCE THIS IS AT THE END OF THE FORECAST PERIOD AND TIMING
DIFFERENCES/ADJUSTMENTS ARE LIKELY TO OCCUR...WILL KEEP POPS BELOW
15% FOR FRI NIGHT INTO SATURDAY...WITH ONLY AN INCREASE IN CLOUD
COVER.
&&
.AVIATION /12Z SUNDAY THROUGH THURSDAY/...
AS OF 100 AM SUNDAY...
A POTENT MID AND UPPER LEVEL TROUGH OVER THE GREAT LAKES AND OHIO
VALLEY WILL DIG SOUTHEAST INTO THE CAROLINAS THROUGH TUESDAY. A
SERIES OF STRONG SHORTWAVE VORTMAXES WILL MOVE ACROSS THE REGION
AS THEY ROTATE THROUGH THE BASE OF THE LONG WAVE TROUGH. THE FIRST
VORT WILL AFFECT THE AREA TODAY...AND IS ALREADY PRODUCING
WIDESPREAD CEILINGS BETWEEN 4 TO 6 KFT...AS WARM AIR ADVECTION IN
ADVANCE OF THE DIGGING WAVE INCREASE OVER THE AREA. RESIDUAL DRY
ARCTIC AIRMASS IN PLACE OVER THE AREA...EVIDENT BY THE SURFACE
DEWPOINT DEPRESSIONS OF 20 TO 25F ACROSS THE CENTRAL AND WESTERN
PIEDMONT...IS STARTING MODIFY ACROSS THE SOUTHERN COASTAL PLAINS
AS SWLY LOW-LEVEL JET CONTINUES TO TRANSPORT LOW AND MID-LEVEL
MOISTURE. SURFACE DEWPOINTS HAVE SURGED INTO THE MID TO UPPER 20S
ACROSS THE SOUTHEAST. PRECIP SHOULD BEGIN TO START TO REACHING THE
GROUND AT KFAY LATER THIS MORNING...WHILE TERMINALS NORTH AND WEST
OF KFAY...WILL BE HARD PRESSURE TO SATURATE THE COLUMN AS
MODELS CONTINUE TO SHOW BEST LIFT AND DEEPEST MOISTURE ACROSS EASTERN
NC THIS AFTERNOON. THIS WILL SUPPORT MVFR CEILINGS AT KFAY AND
KRWI THIS AFTERNOON...WHILE REMAINING SITES SHOULD HOLD ABOVE 3KFT.
MID AND UPPER LEVEL DRYING BEHIND THE UPPER TROUGH WILL
SCOUR OUT THE DEEP MOISTURE SUNDAY EVENING. HOWEVER...MODEL
SOUNDINGS SUGGEST THE POTENTIAL FOR IFR TO LIFR STRATUS SUNDAY NIGHT
AND INTO MONDAY MORNING AS 925MB FLOW BACKS TO SWLY...AS SURFACE
LOW PRESSURE TROUGH REMAINS IN THE LEE OF THE APPALACHIANS.
LOOKING AHEAD...THERE REMAINS A GREAT DEAL OF UNCERTAINTY
FOR MONDAY THROUGH TUESDAY...AS A SERIES OF STRONG UPPER LEVEL
DISTURBANCES ARE PROGGED TO MOVE THROUGH THE AREA. THESE STRONG
DISTURBANCES MAY PRODUCE PERIODIC MVFR TO LOW VFR CIGS AND PERHAPS
SNOW SHOWERS MON AND TUES AS THE SURFACE FRONT FINALLY MOVES EAST
ACROSS THE AREA ON MONDAY...DEVELOPING A WAVE OF LOW PRESSURE LATE
MONDAY AND INTO TUESDAY AS THE FRONT MOVES OFFSHORE.
VFR CONDITIONS ARE THEN EXPECTED WEDNESDAY AND THURSDAY AS EASTERN
US TROUGH LIFTS OFF TO THE NORTHEAST WITH SURFACE RIDGING EXTENDING
INTO THE AREA FROM THE SOUTHWEST.
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...WSS
NEAR TERM...WSS
SHORT TERM...RHJ
LONG TERM...BL
AVIATION...BL
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
636 AM EST SUN JAN 18 2009
.SYNOPSIS...
A COLD FRONT WILL BRING RAIN TO THE AREA TODAY TAPERING OFF THIS
EVENING. A COUPLE OF STRONG MID LEVEL SYSTEMS WILL MOVE ACROSS THE
REGION MONDAY AND TUESDAY. THESE WILL BRING COLD TEMPERATURES TO
THE AREA THROUGH MIDWEEK. A SLOW WARMING TREND SHOULD TAKE PLACE
LATER IN THE WEEK AS HIGH PRESSURE MOVES OFF THE COAST. A FRONT
MAY BRING ANOTHER CHANCE OF SHOWERS NEXT WEEKEND.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 6 AM SUNDAY...NOTABLE WARM AIR ADVECTION REGIME UNDERWAY
ACROSS THE REGION WITH EXTENSIVE 5000-7000 FOOT STRATIFORM CLOUDS
COVERING A VAST PORTION OF THE SE US AHEAD OF A COLD FRONT LOCATED
FROM THE OHIO VALLEY SOUTHWARD TO WESTERN TENNESSEE. LITTLE IN THE
WAY OF PCPN WAS OBSERVED IN METARS EARLY THIS MORNING BENEATH THE
PRE-FRONTAL CLOUDS...BUT AS OVER-RUNNING MOISTURE ATOP MODIFIED
ARCTIC AIR CONTINUES...PCPN WILL LIKELY BREAK OUT MORE IN EARNEST
AFTER DAYBREAK...FOCUSING ALONG AN APPROACHING FRONTAL BOUNDARY AS
THE DAY UNFOLDS. SOMEWHAT UNSETTLING RIGHT NOW ARE DEWPOINTS IN THE
20S ACROSS PORTIONS OF THE FORECAST AREA. WHILE THE CURRENT TREND
DOES SHOW DEWPOINT RISES EARLY THIS MORNING...EVAPORATIVE COOLING AT
THE ONSET OF LIGHT PCPN BETWEEN 6AM-10AM COULD BRIEFLY RESULT IN
LIGHT SNOW OR SLEET BEFORE CHANGING OVER TO RAIN LATER THIS MORNING.
THUS AM DEBATING INCLUDING MENTION FOR THIS POSSIBILITY IN ZONES
THOUGH NO ACCUMULATIONS EXPECTED. THE SOUTHERLY FLOW AHEAD OF THIS
SYSTEM APPEARS WEAK SO HAVE LEANED ON COOL SIDE OF TEMP GUIDANCE
TODAY. AVG QPFS AROUND A QUARTER INCH ACCORDING TO MODEL CONSENSUS
LOOKS REASONABLE FOR THIS FRONTAL PASSAGE...TAPERING RAIN OFF IN THE
EARLY EVENING. WEAK AND BRIEF COLD AIR ADVECTION TNGT SHOULD BRING
LOW TEMPS GENERALLY IN THE 30S TONIGHT.
&&
.SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/...
AS OF 3 AM SUNDAY...THE RELENTLESS BARRAGE OF SHORT WAVES EMBEDDED IN THE
MEAN NORTHWEST FLOW WILL CONTINUE WITH FEATURES BOTH MONDAY AND
TUESDAY AFTERNOON. WITH THIS TYPE OF SYNOPTIC SITUATION IT IS
PRUDENT EVEN THIS FAR SOUTH TO INTERROGATE SOUNDINGS FOR THE
POSSIBILITY OF FROZEN PRECIPITATION. AS FOR THE FIRST SYSTEM...BOTH
THE NAM AND GFS ARE GENERATING OUT A COUPLE OF HUNDREDTHS OF QPF
ACROSS OUR AREA WITH THE NAM A BIT FURTHER NORTH WITH ITS VERSION.
MODEL SOUNDINGS SHOW AN INVERTED-V SIGNATURE INDICATIVE OF THE VERY
DRY AIR MASS AT THE SURFACE. THIS SHOULD PRECLUDE ANY MEASURABLE
PRECIPITATION MONDAY AFTERNOON ALTHOUGH THERE COULD BE A SPRINKLE
AND VIRGA IS ALMOST ASSURED. SURFACE TEMPERATURES SHOULD BE JUST
WARM ENOUGH TO KEEP ANY SPRINKLES OF THE LIQUID VARIETY. ANY
ACTIVITY THAT COULD PERSIST INTO MONDAY EVENING COULD REACH THE
GROUND AS AN ICE PELLET OR WET SNOWFLAKE AS THE BOUNDARY LAYER COOLS
JUST ENOUGH. BUT ONCE AGAIN...DO NOT EXPECT ANYTHING MEASURABLE.
ANOTHER SHORT WAVE DIVES WELL SOUTH OF THE AREA TUESDAY. THE STORY
WITH FEATURE WILL BE THE COLD AIR. STRONG COLD AIR ADVECTION
BASICALLY ALL DAY TUESDAY WARRANTS UNDERCUTTING GUIDANCE FOR
HIGHS...AND IT WILL CERTAINLY NOT SURPRISE ME IF MOST STATIONS SEE
ANOTHER DAY OF HIGHS IN THE 30S. WEDNESDAY MORNING WILL SEE
WIDESPREAD LOW TO MID 20S...ALTHOUGH A STEADY BREEZE AT THE SURFACE
WILL KEEP TEMPERATURES FROM DROPPING INTO THE TEENS MOST PLACES.
&&
.LONG TERM /WEDNESDAY THROUGH SATURDAY/...
AS OF 3 AM SUNDAY...MEDIUM AND LONG RANGE MODELS CONTINUE TO
ADVERTISE THE PERSISTENT EAST COAST TROUGH RELAXING BY THE
WEEKEND. THIS SHOULD ALLOW A WEAK SYSTEM TO MOVE ACROSS LATE
FRIDAY OR EARLY SATURDAY AND MORE IMPORTANTLY...A WARMING TREND TO
COMMENCE WITH THE LATEST MEX NUMBERS ADVERTISING NUMBERS ABOVE
CLIMATOLOGY. WILL WAIT FOR MORE CONSISTENCY BEFORE TEASING THE
PUBLIC WITH HIGHS IN THE 60S FRIDAY AND SATURDAY...BUT WITH THE
PATTERN CHANGE IT IS DOABLE.
&&
.AVIATION /12Z SUNDAY THROUGH THURSDAY/...
VFR AT ALL TERMINALS AT 12Z. AS PRECIPITATION CONTINUES TO INCREASE
THROUGH THE MORNING LOW LEVELS WILL CONTINUE TO BECOME MORE
SATURATED. THERE WILL BE A SLIGHT CHANCE OF SOME SLEET/SNOW MIXED
IN WITH THE RAIN EARLY THIS MORNING BUT IT SHOULD NOT AFFECT
AIRCRAFT OPERATIONS. CEILINGS WILL LOWER TO MVFR BY LATE MORNING
AT FLO/LBT AND BY AFTERNOON AT THE COASTAL TERMINALS. THERE WILL
BE A SLIGHT CHANCE OF IFR VISIBILITIES AT FLO/LBT AFTER 16Z AS
RAIN INCREASES AND BR BEGINS TO DEVELOP.
THIS AFTERNOON IFR CEILINGS EXPECTED TO DEVELOP AT FLO/LBT AND BY
THIS EVENING AT THE COASTAL TERMINALS. SOME IFR VISIBILITIES WILL
ALSO OCCUR AT FLO/LBT THIS AFTERNOON AS PRECIPITATION PEAKS. THE
PRECIPITATION ENDS BY THIS EVENING BUT IFR CEILINGS WILL LIKELY
CONTINUE OVERNIGHT AS MOISTURE WILL BE TRAPPED BENEATH A LOW LEVEL
INVERSION.
EXTENDED OUTLOOK THROUGH THURSDAY...IFR CONDITIONS POSSIBLE EARLY
MONDAY.
&&
.MARINE...
NEAR TERM /THROUGH TONIGHT/...
AS OF 3 AM SUNDAY...WEAK WIND FLOW OVER THE WATERS EARLY THIS
MORNING WITH SEAS AROUND 2 FEET IN ESE SWELL WITH LITTLE CHOP
CURRENTLY. WINDS WILL INCREASE THIS MORNING AS THE COLD FRONT NEARS
BUT GIVEN HOW CHILLY THE WATERS ARE...HAVE OPTED TO POPULATE WINDS
WITH MORE SCALED BACK NAM-12 ON SPEEDS. THUS WILL HOLD CONDITIONS
BELOW SMALL CRAFT ADVISORY THROUGH DAYBREAK MONDAY EITHER SIDE OF
FRONT. EXERCISE CAUTION STATEMENT MAY BE NEEDED TOWARD EVENING BUT
EVEN THIS WILL BE MARGINAL. WILL RETAIN 2-4 FOOT RANGE TODAY AND
BUILD TO 3 TO 5 FEET TONIGHT. WEST TRAJECTORY WILL KEEP NEAR SHORE
SEAS QUITE A BIT SMALLER THAN AWAY FROM SHORE.
SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/...
AS OF 3 AM SUNDAY...WILL SEE A WESTERLY FLOW INITIALLY ACROSS THE
WATERS AS ONE SYSTEM DEPARTS BACKING SLIGHTLY TO SOUTHWEST MONDAY
AFTERNOON AS ANOTHER SHORT WAVE AND ASSOCIATED COLD FRONT MOVES
ACROSS. THE STRONGEST WINDS WILL OCCUR IN THE WAKE OF THIS SYSTEM
LATE MONDAY INTO TUESDAY MORNING AND THIS WILL BE THE NEXT CHANCE
FOR SMALL CRAFT CONDITIONS. TUESDAY WILL FEATURE STRONG COLD AIR
ADVECTION ALTHOUGH WITH THE SECOND SHORT WAVE DROPPING FURTHER
SOUTH...THE LOW LEVEL WIND FIELDS ARE NOT THAT STRONG...AND A
NORTHWEST FLOW OF 15-20 KNOTS SHOULD PERSIST THROUGH WEDNESDAY
MORNING.
WITH WINDS MAINTAINING AN OFFSHORE COMPONENT THROUGH THE
PERIOD...SEAS WILL REMAIN IN A 2-4 FOOT RANGE THE THE POSSIBILITY OF
SOME FIVE FOOTERS IN AMZ252 EARLY TUESDAY.
LONG TERM /WEDNESDAY THROUGH THURSDAY/...
AS OF 3 AM SUNDAY...NO CHANGES TO THE EXTENDED PART OF THE COASTAL
WATERS FORECAST THIS MORNING. MARINERS CAN STILL EXPECT A
CONDITIONS TO RELAX CONSIDERABLY WITH WINDS DROPPING BELOW 15
KNOTS AND SEAS OF 2-3 FEET AS THE AXIS OF HIGH PRESSURE DRIFTS ACROSS.
&&
.ILM WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
NC...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...SHK
NEAR TERM...MJC
SHORT TERM...SHK
LONG TERM...SHK
AVIATION...MRR
MARINE...
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