AREA FORECAST DISCUSSION
NWS DULUTH MN
842 PM CST SAT MAR 8 2008
.DISCUSSION...VERY LITTLE SNOW WAS FALLING OVER THE NORTHLAND THIS
EVENING...THE ONLY OBSERVATION REPORTING -SN AT 02Z WAS KAIT. A
LOOK OUT THE WINDOW HERE SHOWS VERY LIGHT FLURRIES FALLING AS WELL.
AREA RADARS SHOWS THE SNOW WAS DIMINISHING OVER WESTERN MN...IN
LINE WITH WHAT THE MODELS WERE FORECASTING. 285K ISENTROPIC
SURFACE SHOWED GOOD UPGLIDE THIS AFTERNOON...BUT WAS FORECASTING
IT TO QUICKLY DIMINISH AFTER 00Z/9TH.
LAKE EFFECT SNOW OVER THE HEAD OF THE LAKE IS ANOTHER CONCERN
TONIGHT. THERE WERE WEAK RETURNS (-18DBZ) SHOWING UP ON THE KDLH
RADAR THAT WERE LIKELY LAKE CLOUDS OR SOME FLURRIES. THESE RETURNS
HAVE BEEN NEARLY STATIONARY...WHILE THE REST OF THE RETURNS WERE
STRONGER AND ROTATING COUNTER CLOCKWISE ACROSS THE REGION. SET UP
FOR LAKE EFFECT SNOW IS QUESTIONABLE TONIGHT. THE
FETCH...DELTA-T`S AND INVERSION LOOK QUITE FAVORABLE.
HOWEVER...THE AIRMASS IS QUITE DRY. TAMDAR SOUNDINGS FROM CYQT AND
KCMX AND KHIB WERE DRY. CYQT AND KHIB SHOWED DRY LOW
LAYERS...WHILE KCMX WAS VERY DRY ABOVE ABOUT 875MB. THERE IS ALSO
ALOT OF ICE OVER WESTERN LAKE SUPERIOR...BUT WE DON`T KNOW THE
THICKNESS AND PERCENTAGE OF ICE COVER. WE CURRENTLY HAVE A MENTION
OF LIGHT SNOW OR FLURRIES OVER MOST AREAS. WE WILL WATCH FOR ANY
ENHANCEMENT OF THE RETURNS OVER LAKE SUPERIOR...AND ADJUST CHANCES
FOR SNOW.
&&
.AVIATION...MAINLY VFR CONDITIONS...WITH SOME AREAS OF MVFR
CEILINGS AND VSBYS...MAINLY ALONG AND WEST OF A LINE FROM KAIT TO
KINL. THERE MAY ALSO BE SOME MVFR CONDITIONS LATER TONIGHT AT THE
HEAD OF LAKE SUPERIOR.
&&
POINT TEMPS/POPS...
DLH 1 20 8 31 / 40 10 10 10
INL -3 23 6 33 / 40 10 10 10
BRD 5 23 9 35 / 50 20 10 10
HYR -3 22 3 32 / 30 20 10 10
ASX 0 22 9 31 / 20 10 10 10
&&
.DLH WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
$$
MELDE
AREA FORECAST DISCUSSION
NWS BINGHAMTON NY
1252 PM EST SAT MAR 8 2008
.SYNOPSIS...
LOW PRESSURE MOVING INTO NORTHEAST PENNSYLVANIA LATE TODAY WILL
BRING A MIXED BAG OF PRECIPITATION TO THE REGION. AS THE LOW MOVES
INTO NEW ENGLAND TONIGHT, RAIN AND MIXED PRECIPITATION WILL
CHANGE OVER TO SNOW SHOWERS AS GUSTY WINDS BRING IN COLDER AIR.
THE SNOW SHOWERS WILL PERSIST ACROSS UPSTATE NEW YORK ON SUNDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
UPDATED...LTL CHG TO CRNT FCST AND WILL LEAVE ALL FLAGS AS IS.
AREAS ALONG AND W OF I-81 HAVE SFC TEMPS GNRLY IN THE 30-32 RNG,
AND XPCT LTL CHG THIS AFTN. ACRS THESE AREAS, A MIX OF RAIN/FZRA
AND SLEET CAN BE XPCTD. AREAS TO THE SE WILL SEE RAIN AS THE
PRIMARY PCPN TYPE. POTNL FOR CONVECTION THIS AFTN ACRS THE POCONOS
AND SRN CATSKILLS MAY POSE SOME FLASHY HYDRO PRBLMS THIS AFTN/EVNG
AND WILL KEEP A CLOSE EYE ON THIS. WINDS WILL PICK UP THIS EVNG
BEHIND THE LOW. ISALLOBARIC FIELD LOOKS PRETTY GOOD BUT INITIAL
BUFKIT PROFILES SUGGEST LOW END ADVISORY. IN AGREEMENT WITH
BUF/ALY TO HOLD OFF ON ANY WIND HEADLINES ATTM...INITIAL THOUGHT
IS THAT 20-30G4O WOULD WORK FOR MOST OF THE AREA. GIVEN
COMPLEXITY OF FCST ATTM WILL LEAVE HEADLINES AS IS BUT WILL
CONSIDER WIND HEADLINES THIS AFTN. PREV BLO...
WK SFC LOW THAT DEVELOPED OVR THE DELMARVA EARLY THIS MRNG HAS MVD
TO A POSN OFF OF CAPE COD. THIS HAS SERVED TO PULL IN A LITTLE BIT
CLDR AIR FOR THE TIME BEING BUT HAS ALSO TAKEN PCPN WITH IT AS IT
EXITS. RESPITE FROM THE PCPN WILL BE SHORT-LIVED AS MORE IS MVG
QUICKLY NORTH THRU PA WITH LIGHTNING STRIKES ALREADY NOTED OVR
CPA.
UPPER LOW HAS CLOSED OFF OVR THE TN VALLEY WITH ASSOC SFC LOW
MAKING RAPID PROGRESS TO THE NORTH...CURRENTLY LOCATED OVR
VA/TN/NC BORDER. SFC TROF AXIS EXTENDS NORTH OF THE CTR AND TWD FA
WITH GREATEST PRESSURE FALLS OVR WV AT PRESENT. EXPECT THIS LOW
WILL CONTINUE MVG NORTH AND EAST TODAY ALONG BOUNDARY. BOTH
NAM/GFS ARE IN GOOD AGREEMENT ON EVENTUAL POSN OF LOW THIS AFTN.
ONLY DIFFERENCE RMNS IN THE NAM DEVELOPING SECONDARY LOW ALONG THE
COAST THIS AFTN. HOWEVER...WITHIN 6 HRS THE PRIMARILY SFC LOW TAKES
OVR. GFS/SUPER ENSEMBLES/RUC DO NOT SEEM TO BE BUYING INTO THIS
SOLN AND HAVE THUS SIDED TWD GFS SOLN IN THE PLACEMENT OF THE LOW
CTR FOR TODAY.
H5 LOW WILL EJECT NORTH TODAY AS NEXT S/WV DROPS INTO NRN PLAINS
AND KICKS IT OUT. LOW IS PROGGED TO TAKE ON NEGATIVE TILT AS IT
HEADS UP INTO THE OH VALLEY. ALL SHORT AND MEDIUM RANGE GUIDANCE
INDICATES THE LOW CTR TRACKING WEST OF THE FA TODAY. H8/H7 CENTERS
ALSO EXPECTED TO TRACK THRU WRN NY/FINGER LAKES TODAY. AS H8 LOW
TRACKS NORTH...WINDS WILL BACK ARND TO THE SOUTHEAST DRAWING WARMER
AIR INTO CNY AFTR ABOUT 15Z.
CURRENTLY TEMPS ARE SITTING RIGHT ARND FZG. INITIAL BATCH OF PCPN
WILL MV IN BTWN 12Z-15Z. BUFKIT PROFILES FROM THE NAM/GFS/RUC
INDICATE A MIX OF SLEET OR FZRA EARLY THIS MRNG...POSSIBLY MIXED
WITH SNOW ACROSS THE FAR NORTH AS PROFILE RMNS ISOTHERMAL PER
ACARS DATA. AS WARM ADVECTION KICKS IN THE WARM LAYER AT 800MB
INCRS TO ARND +5C. FAR SRN AND ERN ZONES WILL RMN ABV FRZG AND
EXPECT ALL RAIN TODAY. SOME ELEVATED CONVECTION CAN BE EXPECTED
WITH SHOWALTERS DROPPING BLO ZERO AND LAPSE RATES INCRSG TO 6.5-7
FROM 15Z-21Z.
FURTHER NORTH...SLEET AND FREEZING RAIN WILL GIVE WAY TO ALL RAIN
AFTER ABOUT 15Z ACROSS PARTS OF CNY. HIGHER ELEVATIONS MAY RMN
ARND FRZG FOR A GOOD PART OF THE DAY. WITH TEMPS ARND 32F...PCPN
MAY HAVE A HARD TIME ACCUMULATING ON SFCS AND EXPECT ICING OF ONLY
ONE TENTH OF AN INCH OR SO THRU THE DAY ACROSS THE HILLTOPS.
ACROSS THE FINGER LAKES AND FAR NORTH...FREEZING RAIN MAY HOLD ON
A LITTLE LONGER AS TEMPS WILL STRUGGLE INTO THE MIDDLE 30S. UP TO
ONE QUARTER OF AN INCH WILL BE POSSIBLE ALTHO VALLEY LOCATIONS
SHUD WARM UP ENUF TO SEE PLAIN RAIN.
THUS...HAVE LEFT WINTER WX ADVISORIES IN PLACE WHERE THEY
PREVIOUSLY WERE. DELAWARE COUNTY MAY BE A QUESTION MARK AS TO
WHETHER SOME SPOTS MAY SEE SOME ICING BUT HAVE OPTED NOT TO
INCLUDE THEM AS OF YET AS MOST OF THE COUNTY SHUD WARM UP FAIRLY
QUICKLY ALOFT. WINTER STORM WARNINGS FOR STEUBEN...SCHUYLER...
MADISON AND SRN ONEIDA HAVE BEEN DROPPED TO WINTER WX ADVISORIES.
VRY LITTLE SNOW IS EXPECTED TODAY AND ICING AMNTS WILL NOT BE ENUF
TO PUSH THESE AREAS TO WARNING CRITERIA.
REGARDING THE HEAVY RAIN THREAT...H8 JET INCREASES TO 40-50KTS
THIS AFTN WITH A SOUTH-SOUTHEAST TRAJECTORY AS H8 LOW MVS NORTH.
THIS IN CONJUNCTION WITH SRN STREAM SPEED MAX AND POSSIBLE
ELEVATED CONVECTION WILL CONTINUE THE THREAT FOR FLOODING TODAY.
CUD SEE SOME URBAN AND SMALL STREAM FLOODING BUT FEEL THE BETTER
CHC FOR HVY RAIN HAS SHIFTED A LITTLE TO THE EAST BASED ON TRACK
OF SFC LOW AND H8 SPEED MAX. MODELS HV COME IN LIGHTER ON QPF WITH
0.50-1.00 INCHES EXPECTED FROM I-81 CORRIDOR EAST. WITH RIVERS
STILL HIGH AND PROGGED TO RISE TO NR/ABV FLOOD STAGE ON THE
SUSQUEHANNA AND DELAWARE BEST COURSE OF ACTION IS TO KEEP FLOOD
WATCH GOING THRU SUNDAY MORNING. LATER SHIFTS MAY NEED TO CANCEL
IT EARLY GIVEN PROGRESS OF HVY RAIN TO THE EAST.
&&
.SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/...
FCST FOR TONIGHT COMPLICATED WITH REGARD TO SNOWFALL AMNTS/WARNING
CRITERIA PCPN. SFC LOW PASSES THRU THIS EVENING AND DRAWS COLD AIR IN
VRY QUICKLY. TEMPS ALOFT PLUMMET BHND THE STORM WITH H8 TEMPS DOWN
TO NR -15C AFTER 06Z. PCPN WILL CHG TO ALL SNOW OVR MOST OF CNY
AFTER 00Z. QPF FROM 00Z NAM/GFS BOTH GIVE ABOUT ONE HALF INCH
ACROSS THE FINGER LKS/MOHAWK VALLEY OVERNIGHT. TREMENDOUS LIFT
BEING ADVERTISED ALONG WITH RAPIDLY LOWERING SNOW GROWTH LAYER.
INITIAL PLAN WAS TO DROP WARNING FOR THE ENTIRE AREA.
HOWEVER...WRAP- ROUND OCCASIONALLY HAS A TENDENCY TO INTENSIFY
DUE TO THE LAKE INFLUENCE. WITH FAVORABLE SNOW GROWTH
AREA...INTENSE LIFT AND PLENTY OF MOISTURE AVAILABLE OVR NRN
SECTIONS...HAVE OPTED TO KEEP WARNING GOING FROM YATES THRU
ONONDAGA AND NRN ONEIDA. THE BEST CHC FOR 12-HR WARNING CRITERIA
ACCUMS WILL BE FROM PENN YAN TO SYRACUSE TO BOONVILLE WITH 5-8
INCHES POSSIBLE. LIMITING FACTOR IN ALL THIS WILL BE THE SPEED AT
WHICH THE STORM DEPARTS THE AREA. PCPN WILL ONLY HV ABOUT A 4-6 HR
WINDOW TO WORK WITH IN ORDER TO GET WARNING CRITERIA.
THE ADVISORY AREA WILL ONLY SEE ABOUT 1-3 INCHES OF SNOW ACCUMS
OVRNGT BUT SLEET AND FZRA EXPECTED SAT AFTN WARRANTS KEEPING
HEADLINE RUNNING.
NEXT CONCERN FOR TONIGHT WILL BE WINDS BHND THE STORM. TIGHT
PRESSURE GRADIENT WILL EXIST ARND LOW AS IT CONTINUES TO DEEPEN
INTO NRN VT. MODELS HINTING AT H8 WINDS OF 50KTS BLOWING THRU ON
BACKSIDE OF SFC LOW. WUD NOT BE SURPRISED TO SEE GUSTS UP TO 45 KTS
OVERNIGHT OVR THE HILLTOPS. WIND ADVISORY MAY NEED TO BE HOISTED
LATER ON. FOR THE TIME BEING...PREFER TO CVR POTENTIAL IN
SUBSEQUENT WINTER WX HEADLINES AND THE HWO. AREAS OF SNOW AND
BLOWING SNOW CAN BE EXPECTED TONIGHT - ONE MORE FACTOR IN FAVOR OF
KEEPING SOME PORTIONS OF THE WINTER STORM WARNING GOING.
THE SNOW SHUD BEGIN TO TAPER OFF AFTER MIDNIGHT AS LOW RAPIDLY MVS
NORTH AND EAST. LAKE EFFECT SNOW SHOWERS WILL BE POSSIBLE ON
SUNDAY BUT CONDS DO NOT APPEAR TO BE FAVORABLE FOR ADVISORY ACCUMS
WITH THE SNOWS. LAKE EFFECT WILL SLOWLY COME TO AN END ON MONDAY
AS HIPRES TRIES TO BUILD IN.
&&
.LONG TERM /TUESDAY THROUGH FRIDAY/...
WITH FOCUS ON THE SHORT TERM MIXED EVENT ABOUT TO GET UNDERWAY...
WE HAVE FOLLOWED THE HPC GUIDANCE WITH THIS FCST UPDATE. IN
GENERAL...MED RANGE MODELS SUGGEST THAT THE NORTHERN STREAM WILL
INFLUENCE WX ACROSS CNY/NEPA WITH TRANSIENT WEAK SYSTEMS PASSING
THROUGH THE AREA. NOTHING AT THIS TIME LOOKS SIGNIFICANT. COLD
ENOUGH FOR CHC SOME LAKE EFFECT SNOW SHOWERS LINGERING SUN NITE AND
MONDAY. LACK OF SYNOPTIC MOISTURE SHOULD MAKE ANY LES A LIGHT EVENT.
WEAK TROF/FRONT PASSAGES TUESDAY NIGHT AND THURSDAY NIGHT INTO
FRIDAY WITH CHANCES FOR SNOW SHOWERS AT NIGHT...RAIN SHOWERS DURING
THE DAY. HIGH PRESSURE AND DRY CONDITIONS TUESDAY AND WEDS INTO
THURS. TEMPS START OFF BELOW NORMAL...THEN DECENT WAA AHEAD OF FRONT
THURSDAY NIGHT AND FRIDAY SHOULD BRING TEMPS ABOVE.
&&
.AVIATION /18Z SATURDAY THROUGH THURSDAY/...
WDSPRD IFR CIGS/VSBYS WILL CONTINUE WITH PERIODS OF RAIN AND
FREEZING RAIN THIS AFTERNOON. AS DEEPENING LOW PRESSURE NEARS THE
AREA...A DRY SLOT MOVES NORTH FROM CENTRAL VIRGINIA AFTER 21Z.
THIS MAY ALLOW FOR BRIEF IMPROVEMENT OF CIGS/VSBYS TO MVFR AND
PSBLY VFR AT AVP...ELM AND BGM. SHALLOW COLD LAYER MAY HOLD IN THE
IFR FURTHER NORTH AND WEST...ESPLY AS WINDS COME AROUND TO THE
NORTH OFF THE LAKE AT ITH. ALSO EXPECT A LULL IN THE PRECIPITATION
AFTER 21Z. COLD AIR CHANGES PRECIP TO SNOW SHOWERS TONIGHT. CIGS
SHOULD IMPROVE TO MVFR...BUT VSBYS OCNLY MVFR-IFR IN ANY SNOW SHOWERS.
LOW PRESSURE MOVES NORTHEAST TONIGHT AND SUNDAY WITH IMPROVEMENT
TO VFR. MAIN FLIGHT PROBLEM BEGINNING BY MID EVENING AND
CONTINUING INTO SUNDAY WILL BE STRONG WEST-NORTHWEST WINDS. WINDS
LIKELY SUSTAINED 20-30 KTS...GUSTING OCNLY 35-40 KTS.
OUTLOOK...
SUN NITE...MVFR CHC LAKE SNOW SYR-RME. ELSEWHERE VFR.
MON...VFR. NO SIG WX.
TUES...VFR. NO SIG WX.
WED...MVFR-VFR. CHC RAIN OR SNOW SHOWERS.
THU...VFR. NO SIG WX.
&&
.BGM WATCHES/WARNINGS/ADVISORIES...
PA...FLOOD WATCH THROUGH SUNDAY MORNING FOR PAZ038>040-043-044-047-
048-072.
WINTER WEATHER ADVISORY UNTIL 8 AM EDT SUNDAY FOR PAZ038-039.
NY...FLOOD WATCH THROUGH SUNDAY MORNING FOR NYZ009-037-045-046-
055>057-062.
WINTER WEATHER ADVISORY UNTIL 8 AM EDT SUNDAY FOR NYZ022>025-
036-037-044>046-055-056.
WINTER STORM WARNING UNTIL 8 AM EDT SUNDAY FOR NYZ009-015>018.
&&
$$
AVIATION...JAB
AREA FORECAST DISCUSSION
NWS RALEIGH NC
736 PM EST SAT MAR 8 2008
.SYNOPSIS...
A POWERFUL LOW PRESSURE SYSTEM WILL CONTINUE TO MOVE THROUGH NEW
ENGLAND TONIGHT. MEANWHILE... HIGH PRESSURE FROM THE GULF COAST
REGION WILL BUILD INTO CENTRAL NC THROUGH SUNDAY... AND LINGER
THROUGH MONDAY. A WEAK AND DRY COLD FRONT WILL CROSS OUR AREA MONDAY
NIGHT... FOLLOWED BY A RETURN TO HIGH PRESSURE THROUGH THE MIDDLE OF
THE WEEK. THE NEXT RAIN PRODUCING WEATHER SYSTEM IS EXPECTED TO
AFFECT OUR ARE FRIDAY.
&&
.NEAR TERM /UNTIL 6 AM SUNDAY MORNING/...
AS OF 730 PM SATURDAY...
THE WIND ADVISORY HAS BEEN ALLOWED TO EXPIRE FOR ALL OF CENTRAL NC AS
OF 6 PM. A PNS PRELIMINARY SUMMARY OF PEAK WIND GUSTS ACROSS THE
AREA THROUGH 4 PM TODAY HAS ALREADY BEEN ISSUED... AND WILL BE
UPDATED LATER THIS EVENING TO REFLECT ANY ADDITIONAL GUSTS THAT
OCCURRED AFTER 4 PM. THE HIGHEST WINDS REPORTED WERE A TRIO OF 53
MPH GUSTS AT FAYETTEVILLE... ROCKY MOUNT... AND SEYMOUR JOHNSON AFB
IN GOLDSBORO. OTHER GUSTS OF 50 MPH OR MORE INCLUDE RALEIGH DURHAM
AIRPORT (52)... SOUTHERN PINES (50)... AND GOLDSBORO WAYNE MUNICIPAL
AIRPORT (50).
WEATHER CONDITIONS TURNING COLDER AND MORE TRANQUIL ACROSS CENTRAL
NC THIS EVENING. THE EARLIER MIXED RAIN AND SLEET SHOWERS IN THE
TRIAD HAVE ENDED. THESE SHOWERS WERE FORCED IN THE LEFT EXIT REGION
OF A 160 KT UPPER JET PER AMDAR WINDS REPORTED THIS AFTERNOON... AND
BY THE LEADING EDGE OF DCVA ASSOCIATED WITH A VERY POTENT...
NEGATIVELY TILTED UPPER TROUGH... CHARACTERIZED BY A STRATOSPHERIC
INTRUSION TO AROUND 600 MILLIBARS.
SHARPLY COLDER AND DRIER WILL CONTINUE TO SPILL INTO THE FORECAST
AREA TONIGHT. WINDS WILL GRADUALLY SUBSIDE AS THE PRESSURE
GRADIENT LESSENS BETWEEN A DEPARTING 985 MB LOW OVER PA AND WEAK
HIGH PRESSURE BUILDING INTO OUR REGION FROM THE GULF COAST STATES.
TEMPERATURES AND DEWPOINTS HAVE ALREADY FALLEN INTO THE MID 30S
AND MIDDLE TEENS... RESPECTIVELY IN THE TRIAD AS OF 09/00Z... BOTH
SEVERAL DEGREES COLDER THAN EARLIER ANTICIPATED. THE LOW LEVEL
THICKNESS AT KGSO FELL A WHOPPING 64 METERS IN THE PAST 12 HOURS.
QUITE A COOL DOWN INTO THE 30S CONSIDERING IT WAS IN THE LOWER 60S IN
GREENSBORO THIS MORNING. HAVE UPDATED THE HOURLY TEMPERATURE AND
DEWPOINT GRIDDED FORECAST DATA TO REFLECT THESE OBSERVED CONDITIONS
AND TO DISPLAY A QUICKER ARRIVAL OF THE COOLER AND DRIER AIR... AS
IT INFILTRATES THE REMAINDER OF THE CWA OVERNIGHT. LOWS IN THE UPPER
20S TO AROUND FREEZING FROM NW TO SE STILL APPEAR ON TRACK THOUGH...
AS TEMPERATURES SHOULD LEVEL OFF WITH EBBING LOW LEVEL CAA BY
DAYBREAK. UPDATED PRODUCTS HAVE BEEN SENT. UNLESS A MORE CAREFUL
ANALYSIS OF THE 09/00Z UPPER AIR DATA INDICATES SOMETHING
GROUNDBREAKING OR LATER OBSERVATIONAL TRENDS DEVIATE FROM THE
CURRENT FORECAST... NO ADDITIONAL UPDATES ARE PLANNED THIS EVENING.
-MWS
&&
.SHORT TERM /6 AM SUNDAY MORNING THROUGH TUESDAY/...
AS OF 120 PM SATURDAY...
MID LEVEL CONFLUENT FLOW ACROSS THE CENTRAL AND EASTERN STATES WILL
AID IN SFC HIGH PRESSURE BUILDING INTO THE CAROLINAS ON SUNDAY.
WINDS TOMORROW WILL BE SIGNIFICANTLY REDUCED FROM WHAT WE ARE SEEING
TODAY AS THE SFC PRESSURE GRADIENT WEAKENS AND THE WINDS IN THE
MIXED LAYER SUBSIDE. SFC WINDS ARE EXPECTED TO MAINLY BE AROUND 10
KT TOMORROW AFTERNOON. AS FAR AS TEMPS ARE CONCERNED... 1000-850 MB
THICKNESSES ARE FORECAST TO BE 20-25M BELOW NORMAL. THIS WOULD
SUPPORT TEMPS ONLY IN THE MID TO UPPER 40S. HOWEVER...MIXING WILL
OCCUR UP TO 900 MB TOMORROW SO THE DRY ADIABATIC TEMP TECHNIQUE WILL
LIKELY BE CLOSER TO REALITY. BASED ON THIS...WILL FORECAST HIGHS 53
NW TO 57 SE. HIGH PRESSURE WILL MAINTAIN ITS LOCATION OVER CENTRAL
NC SUNDAY NIGHT. THIS SETS UP IDEAL RADIATIONAL COOLING CONDITIONS
WITH A DRY AIRMASS IN PLACE. LOWS SHOULD DIP DOWN INTO THE LOW 30S
IN MOST LOCATIONS WHICH IS SEVERAL DEGREES BELOW NORMAL.
SHORTWAVE ENERGY CURRENTLY LOCATED OVER NORTH DAKOTA AND NORTHERN
MINNESOTA WILL MOVE SOUTHEAST AND APPROACH THE REGION BY LATE
MONDAY...WITH THE ENERGY BECOMING SHEARED OUT AS IT DOES SO. TEMPS
WILL MODERATE ACROSS THE REGION AHEAD OF THE DISTURBANCE WITH HIGHS
CLIMBING BACK CLOSE TO SEASONABLE LEVELS (UPPER 50S TO LOWER 60S).
ONLY AN INCREASE IN MID AND HIGH LEVEL CLOUDS IS ANTICIPATED WITH
THE PASSAGE OF THE MID LEVEL WAVE. PRECIP CHANCES LOOK VERY MEAGER
AS THERE IS NO LOW LEVEL MOISTURE RETURN AHEAD OF THE WAVE AS 850MB
FLOW STAYS WESTERLY. ANOTHER WEAK HIGH WILL BUILD IN ON TUESDAY AND
SHOULD KNOCK A DEGREE OR TWO OFF HIGHS COMPARED TO MONDAY BUT STILL
CLOSE TO NORMAL.
&&
.LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/...
AS OF 120 PM SATURDAY...
MANY UNCERTAINTIES EXIST WITH THE EXTENDED PORTION OF THE FORECAST.
THE PATTERN ACROSS NORTH AMERICA WILL BECOME PROGRESSIVE WITH THE
PACIFIC JET EXPECTED TO BECOME VERY ACTIVE. IT IS WITH THE ENERGY
EMBEDDED IN THE FAST PACIFIC FLOW THAT THE MODELS ARE HAVING A HARD
TIME HANDLING. IT WILL TAKE A FEW DAYS FOR DETAILS TO BE WORKED
OUT...SO FOR NOW THE FORECAST WILL BE BASED HEAVILY ON THE
GFS/CANADIAN ENSEMBLE MEAN WHICH IS IN RATHER GOOD AGREEMENT.
TEMPERATURES ARE EXPECTED TO MODERATE BY MIDWEEK WITH SHORTWAVE
RIDGING BUILDING INTO THE EAST AS AMPLE PACIFIC ENERGY CRASHES
INTO THE WEST COAST. HIGHS LIKELY TO BE IN THE MID TO UPPER 60S
WED/THU. BY FRIDAY...ENSEMBLE GUIDANCE POINTS TO THE PACIFIC ENERGY
PHASING INTO A BROAD TROUGH AS IT PROGRESSES TOWARD THE EAST COAST.
WILL CARRY SMALL CHANCES OF RAIN FRIDAY INTO SATURDAY FOR NOW. THE
OP GFS AND SEVERAL OF ITS ENSEMBLES EVEN SHOW A RATHER STRONG LOW
MOVING UP THE WESTERN PORTION OF NORTH CAROLINA. SUCH A SOLUTION
WOULD BRING HIGHER CHANCES OF RAIN AND EVEN A CHANCE OF THUNDER TO
OUR REGION GIVEN STRONGER FORCING AND A BETTER CHANCE OF
INSTABILITY. HOWEVER...WITH THE UNCERTAINTIES STATED ABOVE...WILL
MENTION JUST SHOWERS FOR NOW.
&&
.AVIATION /00Z SUNDAY THROUGH THURSDAY/...
AS OF 1215 PM SATURDAY...
COLD FRONT HAS SWEPT ACROSS REGION WITH STRONG SW WINDS OCCURRING
BEHIND THE BOUNDARY. MEASURED GUST AROUND 50 MPH HAVE OCCURRED AT
KFAY. EXPECT GUSTS 40-45KTS AT MOST SITES THROUGH 23Z. WITH
SUNSET....EXPECT GUSTS TO SUBSIDE TO NEAR 30 KTS THIS EVENING. WINDS
WILL SLOWLY VEER FROM SW TO W THIS EVENING. AFTER 04Z...AS SURFACE
LOW CONTINUES TO PULL AWAY FROM THE REGION AND HIGH PRESSURE OVER
THE N CENTRAL GULF BUILDS INTO AREA...EXPECT WINDS TO SUBSIDE TO
AROUND 10 KTS WITH INFREQUENT GUSTS NEAR 20 KT. CYCLONIC FLOW AND
CAA WILL MAINTAIN SCATTERED TO BROKEN LAYER OF STRATOCU. EXPECT THIS
CLOUD DECK TO DISSIPATE AFTER SUNSET WITH CLEAR SKIES EXPECTED AFTER
03Z THROUGH 23Z SUN.
VFR CONDITIONS ARE ANTICIPATED TO CONTINUE MONDAY THROUGH
THURSDAY.
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...MWS
NEAR TERM...MWS
SHORT TERM...JFB
LONG TERM...JFB
AVIATION...WSS
AREA FORECAST DISCUSSION
NWS RALEIGH NC
721 PM EST SAT MAR 8 2008
.SYNOPSIS...
A POWERFUL LOW PRESSURE SYSTEM WILL CONTINUE TO MOVE THROUGH NEW
ENGLAND TONIGHT. MEANWHILE... HIGH PRESSURE FROM THE GULF COAST REGION
WILL BUILD INTO CENTRAL NC THROUGH SUNDAY... AND LINGER THROUGH
MONDAY. A WEAK AND DRY COLD FRONT WILL CROSS OUR AREA MONDAY
NIGHT... FOLLOWED BY A RETURN TO HIGH PRESSURE THROUGH THE MIDDLE
OF THE WEEK. THE NEXT RAIN PRODUCING WEATHER SYSTEM IS EXPECTED TO
AFFECT OUR ARE FRIDAY.
&&
.NEAR TERM /UNTIL 6 AM SUNDAY MORNING/...
AS OF 640 PM SATURDAY...
THE WIND ADVISORY HAS BEEN ALLOWED TO EXPIRE FOR ALL OF CENTRAL NC AS
OF 6 PM.
WEATHER CONDITIONS TURNING COLDER AND MORE TRANQUIL ACROSS CENTRAL
NC THIS EVENING. THE EARLIER MIXED RAIN AND SLEET SHOWERS IN THE
TRIAD HAVE ENDED. THESE SHOWERS WERE FORCED IN THE LEFT EXIT REGION
OF A 160 KT UPPER JET PER AMDAR WINDS REPORTED THIS AFTERNOON... AND
BY THE LEADING EDGE OF DCVA ASSOCIATED WITH A VERY POTENT...
NEGATIVELY TILTED UPPER TROUGH... CHARACTERIZED BY A STRATOSPHERIC
INTRUSION TO AROUND 600 MILLIBARS.
SHARPLY COLDER AND DRIER WILL CONTINUE TO SPILL INTO THE FORECAST
AREA TONIGHT. WINDS WILL GRADUALLY SUBSIDE AS THE PRESSURE
GRADIENT LESSENS BETWEEN A DEPARTING 985 MB LOW OVER PA AND WEAK
HIGH PRESSURE BUILDING INTO OUR REGION FROM THE GULF COAST STATES.
TEMPERATURES AND DEWPOINTS HAVE ALREADY FALLEN INTO THE MID 30S
AND MIDDLE TEENS... RESPECTIVELY IN THE TRIAD AS OF 09/00Z... BOTH
SEVERAL DEGREES COLDER THAN EARLIER ANTICIPATED. THE LOW LEVEL
THICKNESS AT KGSO FELL A WHOPPING 64 METERS IN THE PAST 12 HOURS. QUITE
A COOL DOWN INTO THE 30S CONSIDERING IT WAS IN THE LOWER 60S IN
GREENSBORO THIS MORNING. HAVE UPDATED THE HOURLY TEMPERATURE AND
DEWPOINT GRIDDED FORECAST DATA TO REFLECT THESE OBSERVED
CONDITIONS AND TO DISPLAY A QUICKER ARRIVAL OF THE COOLER AND
DRIER AIR... AS IT INFILTRATES THE REMAINDER OF THE CWA
OVERNIGHT. LOWS IN THE UPPER 20S TO AROUND FREEZING FROM NW TO SE
STILL APPEAR ON TRACK THOUGH... AS TEMPERATURES SHOULD LEVEL OFF
WITH EBBING LOW LEVEL CAA BY DAYBREAK. UPDATED PRODUCTS HAVE BEEN
SENT. UNLESS A MORE CAREFUL ANALYSIS OF THE 09/00Z UPPER AIR DATA
INDICATES SOMETHING GROUNDBREAKING OR LATER OBSERVATIONAL TRENDS
DEVIATE FROM THE CURRENT FORECAST... NO ADDITIONAL UPDATES ARE
PLANNED THIS EVENING. -MWS
&&
.SHORT TERM /6 AM SUNDAY MORNING THROUGH TUESDAY/...
AS OF 120 PM SATURDAY...
MID LEVEL CONFLUENT FLOW ACROSS THE CENTRAL AND EASTERN STATES WILL
AID IN SFC HIGH PRESSURE BUILDING INTO THE CAROLINAS ON SUNDAY.
WINDS TOMORROW WILL BE SIGNIFICANTLY REDUCED FROM WHAT WE ARE SEEING
TODAY AS THE SFC PRESSURE GRADIENT WEAKENS AND THE WINDS IN THE
MIXED LAYER SUBSIDE. SFC WINDS ARE EXPECTED TO MAINLY BE AROUND 10
KT TOMORROW AFTERNOON. AS FAR AS TEMPS ARE CONCERNED... 1000-850 MB
THICKNESSES ARE FORECAST TO BE 20-25M BELOW NORMAL. THIS WOULD
SUPPORT TEMPS ONLY IN THE MID TO UPPER 40S. HOWEVER...MIXING WILL
OCCUR UP TO 900 MB TOMORROW SO THE DRY ADIABATIC TEMP TECHNIQUE WILL
LIKELY BE CLOSER TO REALITY. BASED ON THIS...WILL FORECAST HIGHS 53
NW TO 57 SE. HIGH PRESSURE WILL MAINTAIN ITS LOCATION OVER CENTRAL
NC SUNDAY NIGHT. THIS SETS UP IDEAL RADIATIONAL COOLING CONDITIONS
WITH A DRY AIRMASS IN PLACE. LOWS SHOULD DIP DOWN INTO THE LOW 30S
IN MOST LOCATIONS WHICH IS SEVERAL DEGREES BELOW NORMAL.
SHORTWAVE ENERGY CURRENTLY LOCATED OVER NORTH DAKOTA AND NORTHERN
MINNESOTA WILL MOVE SOUTHEAST AND APPROACH THE REGION BY LATE
MONDAY...WITH THE ENERGY BECOMING SHEARED OUT AS IT DOES SO. TEMPS
WILL MODERATE ACROSS THE REGION AHEAD OF THE DISTURBANCE WITH HIGHS
CLIMBING BACK CLOSE TO SEASONABLE LEVELS (UPPER 50S TO LOWER 60S).
ONLY AN INCREASE IN MID AND HIGH LEVEL CLOUDS IS ANTICIPATED WITH
THE PASSAGE OF THE MID LEVEL WAVE. PRECIP CHANCES LOOK VERY MEAGER
AS THERE IS NO LOW LEVEL MOISTURE RETURN AHEAD OF THE WAVE AS 850MB
FLOW STAYS WESTERLY. ANOTHER WEAK HIGH WILL BUILD IN ON TUESDAY AND
SHOULD KNOCK A DEGREE OR TWO OFF HIGHS COMPARED TO MONDAY BUT STILL
CLOSE TO NORMAL.
&&
.LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/...
AS OF 120 PM SATURDAY...
MANY UNCERTAINTIES EXIST WITH THE EXTENDED PORTION OF THE FORECAST.
THE PATTERN ACROSS NORTH AMERICA WILL BECOME PROGRESSIVE WITH THE
PACIFIC JET EXPECTED TO BECOME VERY ACTIVE. IT IS WITH THE ENERGY
EMBEDDED IN THE FAST PACIFIC FLOW THAT THE MODELS ARE HAVING A HARD
TIME HANDLING. IT WILL TAKE A FEW DAYS FOR DETAILS TO BE WORKED
OUT...SO FOR NOW THE FORECAST WILL BE BASED HEAVILY ON THE
GFS/CANADIAN ENSEMBLE MEAN WHICH IS IN RATHER GOOD AGREEMENT.
TEMPERATURES ARE EXPECTED TO MODERATE BY MIDWEEK WITH SHORTWAVE
RIDGING BUILDING INTO THE EAST AS AMPLE PACIFIC ENERGY CRASHES
INTO THE WEST COAST. HIGHS LIKELY TO BE IN THE MID TO UPPER 60S
WED/THU. BY FRIDAY...ENSEMBLE GUIDANCE POINTS TO THE PACIFIC ENERGY
PHASING INTO A BROAD TROUGH AS IT PROGRESSES TOWARD THE EAST COAST.
WILL CARRY SMALL CHANCES OF RAIN FRIDAY INTO SATURDAY FOR NOW. THE
OP GFS AND SEVERAL OF ITS ENSEMBLES EVEN SHOW A RATHER STRONG LOW
MOVING UP THE WESTERN PORTION OF NORTH CAROLINA. SUCH A SOLUTION
WOULD BRING HIGHER CHANCES OF RAIN AND EVEN A CHANCE OF THUNDER TO
OUR REGION GIVEN STRONGER FORCING AND A BETTER CHANCE OF
INSTABILITY. HOWEVER...WITH THE UNCERTAINTIES STATED ABOVE...WILL
MENTION JUST SHOWERS FOR NOW.
&&
.AVIATION /00Z SUNDAY THROUGH THURSDAY/...
AS OF 1215 PM SATURDAY...
COLD FRONT HAS SWEPT ACROSS REGION WITH STRONG SW WINDS OCCURRING
BEHIND THE BOUNDARY. MEASURED GUST AROUND 50 MPH HAVE OCCURRED AT
KFAY. EXPECT GUSTS 40-45KTS AT MOST SITES THROUGH 23Z. WITH
SUNSET....EXPECT GUSTS TO SUBSIDE TO NEAR 30 KTS THIS EVENING. WINDS
WILL SLOWLY VEER FROM SW TO W THIS EVENING. AFTER 04Z...AS SURFACE
LOW CONTINUES TO PULL AWAY FROM THE REGION AND HIGH PRESSURE OVER
THE N CENTRAL GULF BUILDS INTO AREA...EXPECT WINDS TO SUBSIDE TO
AROUND 10 KTS WITH INFREQUENT GUSTS NEAR 20 KT. CYCLONIC FLOW AND
CAA WILL MAINTAIN SCATTERED TO BROKEN LAYER OF STRATOCU. EXPECT THIS
CLOUD DECK TO DISSIPATE AFTER SUNSET WITH CLEAR SKIES EXPECTED AFTER
03Z THROUGH 23Z SUN.
VFR CONDITIONS ARE ANTICIPATED TO CONTINUE MONDAY THROUGH
THURSDAY.
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...MWS
NEAR TERM...MWS
SHORT TERM...JFB
LONG TERM...JFB
AVIATION...WSS
AREA FORECAST DISCUSSION
NWS SEATTLE WA
920 AM PST SAT MAR 8 2008
.SYNOPSIS...CLOUDS WILL DECREASE EARLY THIS AFTERNOON AS HIGH
PRESSURE AT THE SURFACE AND A RIDGE OF HIGH PRESSURE ALOFT MOVES
INTO THE AREA. A WARM FRONT WILL MOVE ACROSS THE AREA LATE SUNDAY
AFTERNOON AND SUNDAY NIGHT GIVING RAIN TO THE AREA...MAINLY THE
COAST. A STRONGER AND WINDIER FRONTAL SYSTEM WILL MOVE ACROSS THE
AREA MONDAY AND TUESDAY. UNSETTLED AND COOL WEATHER WILL CONTINUE
FOR THE SECOND HALF OF NEXT WEEK.
&&
.SHORT TERM...POST FRONTAL ONSHORE FLOW IS DECREASING THIS MORNING.
BUT MOISTURE REMAINS TRAPPED BELOW A FRONTAL INVERSION WITH CLOUD
BASES AROUND 015-020 PER SURFACE OBSERVATIONS AND TOPS 027-030 PER
AIRCRAFT REPORTS. THE LOW LEVEL MOISTURE WILL GRADUALLY ERODE AWAY
FROM THE WEST LATER TODAY AS THE FRONTAL INVERSION WEAKENS AND MARCH
INSOLATION WORKS ON THE BOUNDARY LAYER. NAM BUFR SOUNDINGS SHOW LOW
LEVEL MOISTURE NOT SCATTERING OUT UNTIL 22Z-23Z AROUND SEATTLE...SO
CURRENT FORECASTS MAY BE A BIT QUICK TO CLEAR THINGS OUT
TODAY...WILL UPDATE FORECAST WORDING TO RETAIN TRENDS BUT TO SLOW
CLEARING. WILL ALSO REMOVE MORNING SHOWERS FROM THE LOWLANDS AS
REMAINING AND DISSIPATING SHOWER ACTIVITY IS CONFINED TO HIGHER
TERRAIN EAST OF THE ARLINGTON-BELLINGHAM AREA.
CLEARING THIS EVENING WILL RESULT IN GOOD RADIATIONAL COOLING
OVERNIGHT AND PATCHY FOG FORMATION IN THE SOUTH INTERIOR AND FOG
PRONE VALLEYS EAST AND NORTH OF THE SEATTLE EVERETT AREAS. FORECAST
TEMPERATURES THROUGH SUNDAY LOOK GOOD.
A WARM FRONT WILL MOVE NORTHEAST ACROSS THE AREA SUNDAY NIGHT...AND
AT THIS TIME IT APPEARS THAT PRECIPITATION WILL BEGIN DURING THE
AFTERNOON HOURS AND SPREAD NORTHEAST ACROSS THE AREA MAINLY SUNDAY
NIGHT. WARM FRONTOGENESIS ALREADY APPEARS TO BE OCCURING OFF THE
NORTHERN CALIFORNIA AND SOUTH OREGON COASTS PER SATELLITE
IMAGERY...SO MODEL PRECIPITATION FORECASTS FOR SUNDAY NIGHT LOOK
GOOD...THOUGH THE WETTER GLOBAL MODELS...PARTICULARLY THE
ECMWF...ARE PREFERRED. NIGHTTIME LOWS MAY BE A BIT LOW FOR SUNDAY
NIGHT BUT WILL MAKE THOSE CHANGES ON THE NEXT PACKAGE.
A STRONGER...WETTER SYSTEM WILL MOVE THROUGH THE AREA MONDAY INTO
TUESDAY...AND IT APPEARS THAT IT WILL BECOME RATHER WINDY LATE
MONDAY NIGHT INTO TUESDAY AS THE REMNANTS OF A BENT BACK OCCLUSION
DRAGS NORTHEAST ACROSS THE REGION.
CHANGES THIS MORNING WILL BE LIMITED TO CLOUDS AND PRECIPITATION
PERIOD ONE. ALBRECHT
.LONG TERM...PREVIOUS LONG TERM DISCUSSION FOLLOWS...THE EXTENDED
MODELS REMAIN IN RELATIVE AGREEMENT ON THE TRENDS FOR NEXT WEEK.
FOLLOWING AN UPPER LEVEL TROUGH PASSING ACROSS THE AREA ON
TUESDAY...IT LOOKS LIKE WE WILL SEE ANOTHER BRIEF DRY PERIOD
MIDWEEK. ALTHOUGH THEY DIFFER IN MINOR DETAILS...THE MODELS
GENERALLY AGREE ON A BROAD UPPER LEVEL TROUGH TAKING UP RESIDENCE
ALONG THE WEST COAST FOR THE SECOND HALF OF NEXT WEEK...LEADING TO A
COOL AND UNSETTLED PERIOD. 27
NOTE: A VALVE TEST AT THE CUSHMAN DAM ON TODAY WILL CAUSE UNUSUAL
FLUCTUATIONS ALONG THE NORTH FORK SKOKOMISH RIVER AND COULD POSE A
HAZARD TO RECREATIONAL USERS OF THE RIVER TODAY. SEE THE HYDROLOGIC
STATEMENT ISSUED AT 900 AM PST FRIDAY FOR DETAILS. THE AWIPS PIL IS
SEARVSSEW...WMO HEADER FGUS86 KSEW. FOR WEB USERS (IN LOWER
CASE)...HTTP://WWW.WRH.NOAA.GOV/SEW/GET.PHP?WFO=SEW&PIL=RVS&SID=SEW
&&
.AVIATION...THERE WERE WIDESPREAD CIGS OF 1-3K FT...TOPS NEAR 6 OR
7K FT...ACROSS THE AREA AT THIS TIME ALONG WITH A FEW SHOWERS. THE
SHOWERS WILL END BY NOON...EXCEPT OVER THE CASCADES WHERE THE
SHOWERS MAY LINGER INTO THE EARLY AFTERNOON. MEANWHILE...CIGS WILL
GRADUALLY LIFT DURING THE NEXT FEW HOURS. BY 21Z...CIGS SHOULD
MOSTLY BE IN THE 4-6K FT RANGE. BY 01Z...THE CLOUDS WILL HAVE BECOME
SCATTERED.
KSEA...CIGS NEAR 1K FT WILL LIFT TO AROUND 2K FT BY 20Z AND TO NEAR
5K FT BY 22Z. THE CLOUDS WILL SCATTER OUT BETWEEN 22Z AND 00Z. WINDS
WILL BE SLY 5-9 KNOTS.
&&
.MARINE...AN ELONGATED AREA OF HIGH PRES ALONG THE WASHINGTON COAST
WILL RESULT IN WEAK ONSHORE FLOW TODAY. OFFSHORE FLOW WILL DEVELOP
TONIGHT IN RESPONSE TO FALLING PRESSURES OVER THE ERN PAC. A
WEAKENING FRONTAL SYSTEM MOVING ACROSS THE OFFSHORE WATERS ON SUNDAY
IS EXPECTED TO DISSIPATE BEFORE REACHING THE WASHINGTON COASTAL
WATERS. A MUCH STRONGER SYSTEM WILL AFFECT THE AREA ON MON...WITH
GALE FORCE WINDS LIKELY ACROSS MUCH OF THE AREA MON THRU TUE.
&&
.SEW WATCHES/WARNINGS/ADVISORIES...
WA...NONE.
PZ...SMALL CRAFT ADVISORY COASTAL WATERS FOR HAZARDOUS SEAS.
SMALL CRAFT ADVISORY FOR ROUGH GRAYS HARBOR BAR CONDITIONS.
$$
WEATHER.GOV/SEATTLE
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