AREA FORECAST DISCUSSION
NWS SAN DIEGO CA
200 PM PDT SUN MAY 11 2008
.SYNOPSIS...
A TROUGH OF LOW PRESSURE MOVING THROUGH THE WESTERN STATES WILL
BRING STRONGER ONSHORE FLOW...A DEEPER MARINE LAYER...AND COOLER
WEATHER THROUGH MONDAY. THIS TROUGH WILL ALSO INCREASE WINDS IN THE
MOUNTAINS AND DESERTS MONDAY AFTERNOON AND EVENING. FOR TUESDAY
THROUGH THE END OF THE WEEK...STRONG HIGH PRESSURE WILL BUILD ALONG
THE WEST COAST WITH DRIER AND MUCH WARMER WEATHER FOR WEDNESDAY INTO
THE WEEKEND.
&&
.DISCUSSION...FOR EXTREME SOUTHWESTERN CALIFORNIA INCLUDING ORANGE...
SAN DIEGO...WESTERN RIVERSIDE AND SOUTHWESTERN SAN BERNARDINO
COUNTIES...
AN APPROACHING UPPER LEVEL LOW FROM THE NORTHWEST WILL DEEPEN THE
MARINE LAYER TONIGHT AND MON ALLOWING THE LOW CLOUDS TO BE MORE
PERSISTENT IN THE COASTAL BASIN. THERE WILL BE PATCHY DRIZZLE UNDER
THE CLOUDS AS WELL AS FOG ON THE COASTAL MTN SLOPES LATE TONIGHT AND
MON MORNING. WE DO NOT EXPECT MUCH CLEARING AT ALL IN THE COASTAL
BASIN MON. THIS TROUGH WILL ALSO CRANK UP WINDS IN THE MTNS AND
DESERTS MON AFTERNOON AND EVE. AS THE LOW MOVES EASTWARD TUE THE
WEATHER WILL TREND FROM DEEP MARINE LAYER TUE MORNING TO CLEARER AND
WARMER BY WED. A STRONG UPPER HIGH WILL NOSE IN FROM THE PACIFIC AND
WILL STRENGTHEN AND AMPLIFY ALONG THE WEST COAST WED INTO THE
WEEKEND. THIS WILL SQUASH THE MARINE LAYER DOWN TO ALMOST NOTHING...
AND IF ANY COASTAL CLOUDS ARE LEFT OVER...A TOUCH OF OFFSHORE FLOW
SHOULD FINISH THEM BY THU OR FRI. THE BIG STORY WILL BE MUCH HIGHER
DAYTIME TEMPS APPROACHING RECORD LEVELS. THIS SEEMS TO BE THE
PATTERN THIS SPRING...COOL MARINE INFLUENCED WEATHER MIXED WITH HOT
DRY EPISODES. THE UPPER HIGH BEGINS TO BREAK DOWN NEXT WEEKEND AND
TEMPS WILL TREND BACK TO NORMAL EARLY NEXT WEEK.
&&
.AVIATION...
111945Z...LATE MORNING MDCRS SOUNDINGS CONTINUE TO SHOW THE MARINE
LAYER DEPTH AROUND 3000 FEET. THE MARINE LAYER IS FORECAST TO DEEPEN
TO BETWEEN 3500 AND 4000 FEET TONIGHT.
STRATUS WITH BASES AROUND 2500 FEET MSL WAS BEING SLOW TO BREAK UP
NEAR KSNA BUT SOME SCATTERING OF THE STRATUS IS EXPECTED THIS
AFTERNOON. STRATUS SHOULD RETURN TO THE COASTLINE BY SUNSET AND PUSH
INLAND DURING THE EVENING REACHING THE FAR INLAND VALLEY AREAS BY
MIDNIGHT. LITTLE OR NO BREAKUP OF THE STRATUS IS EXPECTED ON MONDAY.
ABOVE THE MARINE LAYER INCLUDING THE MOUNTAINS AND DESERTS...MOSTLY
CLEAR WITH UNRESTRICTED VISIBILITIES WILL CONTINUE THROUGH MONDAY.
&&
.SGX WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
PUBLIC...MM
AVIATION/MARINE...HORTON
SOUTHWEST CALIFORNIA AREA FORECAST DISCUSSION...UPDATED
NWS LOS ANGELES/OXNARD CA
1045 AM PDT SUN MAY 11 2008
UPDATED AVIATION SECTION
.SHORT TERM (TODAY THROUGH TUESDAY)...
STRATUS ALREADY STARTING TO BREAK UP ALONG THE CENTRAL COAST THIS
MORNING...BUT A RATHER SOLID LAYER PERSISTS JUST OFF THEIR IMMEDIATE
COAST...AS WELL AS BLANKETING THE ENTIRE COASTAL AND VALLEY AREAS
SOUTH OF PT CONCEPTION. LATEST AIRCRAFT SOUNDINGS SHOW THE MARINE
LAYER NEAR 2800 FT AT LAX...AND WITH RATHER LOW CEILINGS FOR THIS
DEEP OF A MARINE LAYER...THE STRATUS LAYER LOOKS PRETTY THICK. THIS
THICK LAYER...WHEN COUPLED WITH A STRENGTHENING ONSHORE GRAD...HAS
TO SUGGEST A RATHER TOUGH CLEARING DAY. NOT ONLY THAT...BUT THE
STRENGTHENING GRADS WILL HELP THE STRATUS PUSH EVEN DEEPER INLAND
INTO THE AFTERNOON...AND EXPECTING THE COASTAL SLOPES AND SANTA
CLARITA VALLEY TO BE COVERED BY NOON. A SIMILAR IF NOT MORE
BLANKETED DAY IS EXPECTED FOR MON. UPDATED THE FORECAST TO ADD SOME
PESSIMISM IN THIS REGARD.
TEMPS LOOK GOOD OVERALL...WITH A FEW DEGREES OF COOLING EXPECTED
TODAY AND AGAIN ON MON ACROSS THE BOARD. THANKS CAN BE GIVEN TO THE
INCREASED CLOUD COVERAGE AND LOWER THICKS FROM A LOW CURRENTLY OVER
WASHINGTON THAT CONTINUES TO SAG SOUTHWARD. A MODERATE ONSHORE WIND
DAY IS EXPECTED. ALTHOUGH NO WIND ADVISORIES ARE ANTICIPATED AT THIS
TIME...IT SHOULD GET BREEZY IN THE ANTELOPE VALLEY. MON LOOKS A BIT
WINDIER...AND ADVISORIES ARE NOT OUT OF THE QUESTION IN THE ANTELOPE
VALLEY...AND TO A LESSER EXTENT THE CENTRAL COAST AND SANTA CLARITA
VALLEY.
...FROM PREVIOUS DISCUSSION...
BY MONDAY NIGHT/TUESDAY...MARINE LAYER SHOULD BE LESS IN DEPTH AND
AREAL COVERAGE AS SOME NORTHERLY FLOW IS INDICATED BY 00Z MODELS.
SO...BY TUESDAY AFTERNOON...SKIES SHOULD BE SUNNY FOR ALL AREAS.
.LONG TERM (TUESDAY NIGHT THROUGH SATURDAY)...EXTENDED MODELS
CONTINUE TO ADVERTISE A VERY WARM AND DRY PATTERN FOR THE AREA
THROUGH THE PERIOD. BOTH THE GFS/ECMWF HANDLES THE UPPER HIGH
OVER THE WEST COAST VERY WELL. THE DIFFERENCES BETWEEN THE GFS
AND ECMWF CONTINUE TO BE WITH THE TROUGH OVER THE CENTRAL STATES.
THE GFS KEEPS THE TROUGH OVER NEW MEXICO/WESTERN TEXAS WHILE THE
ECMWF IS MORE PROGRESSIVE WITH THE TROUGH. ADMITTEDLY THE LOCATION
OF THE UPPER TROUGH WILL HAVE SOME INFLUENCE ON THE OVERALL
PATTERN...BUT EITHER WAY...IT STILL WILL BE A VERY WARM FEW DAYS
LATER IN THE WEEK DUE TO VARYING DEGREES OF OFFSHORE FLOW.
LOCAL TEMP STUDY GUIDANCE DEFINITELY SUPPORTS POTENTIAL FOR
SIGNIFICANTLY WARM TEMPS DURING THE PERIOD...ESPECIALLY WEDNESDAY
AND THURSDAY. HAVE BUMPED UP PREVIOUS SHIFT`S TEMPS FOR WEDNESDAY
AND THURSDAY. HOWEVER...IF MODEL TRENDS CONTINUE IN THE SAME VEIN
COASTAL/VALLEY TEMPS WILL BE SEVERAL DEGREES THAN FORECASTED THIS
MORNING. SO...SITUATION WILL HAVE TO BE MONITORED CLOSELY.
BY FRIDAY/SATURDAY...THE OFFSHORE GRADIENTS START TO WEAKEN AS
THE UPPER HIGH WEAKENS. SO...WILL EXPECT SOME COOLER TEMPS NEXT
WEEKEND...BUT STILL WARMER THAN NORMAL CONDITIONS THROUGH THE
PERIOD.
&&
.AVIATION...11/1800Z.
A WEAK UPPER LEVEL TROUGH OF LOW PRESSURE UPSTREAM WILL CONTINUE
SHIFTING EAST AND EXIT THE AREA BY THE END OF THE PERIOD. MODERATE
UPPER LEVEL SOUTHWEST WINDS WILL BECOME MODERATE NORTH BY LATE IN
THE PERIOD. A WEAK TO MODERATE PRESSURE GRADIENT WILL BECOME
MODERATE TO STRONG IN THE AFTERNOON THEN WEAKEN AND PERSIST OVER
NIGHT. ONSHORE WINDS WILL STRENGTHEN IN THE AFTERNOON AND GRADUALLY
DIMINISH OVERNIGHT. THERE IS A CHANCE CIGS WILL ASCEND WHILE THE
UPPER TROUGH APPROACHES AND TRANSITS THE AREA TONIGHT.
KLAX...THERE IS A CHANCE CIGS WILL PERSIST THROUGH THE AFTERNOON.
IT IS LIKELY CIGS WILL RETURN DURING THE EVENING. THERE IS A CHANCE
CIGS WILL ASCEND TO 020-025 IN THE LATER PERIOD.
KBUR...THERE IS A CHANCE CIGS WILL CONTINUE THROUGH THE EARLY
PERIOD. IT IS LIKELY CIGS WILL RETURN DURING THE EVENING AND RANGE
BETWEEN 012-018.
VIRTUALLY CERTAIN - 95-100%
VERY LIKELY - 80-95%
LIKELY - 60-80%
CHANCE - 30-60%
NOT VERY LIKELY - 20% OR LESS
&&
.LOX WATCHES/WARNINGS/ADVISORIES...
SMALL CRAFT ADVISORY (SEE LAXCWFLOX).
&&
$$
PUBLIC...KITTELL/THOMPSON
AVIATION...30
WWW.WEATHER.GOV/LOSANGELES
AREA FORECAST DISCUSSION
NWS BALTIMORE MD/WASHINGTON DC
301 PM EDT SUN MAY 11 2008
.SYNOPSIS...
A POTENT STORM SYSTEM WILL APPROACH FROM THE OHIO VALLEY THIS
EVENING...PASSING THROUGH OUR REGION OVERNIGHT. IT WILL SLOWLY
MOVE OFF THE MID-ATLANTIC COAST MONDAY. SIGNIFICANT RAINFALL IS
EXPECTED FROM THIS STORM SYSTEM WITH THE HEAVIEST RAIN EXPECTED
LATER THIS AFTERNOON THROUGH TONIGHT. HIGH PRESSURE WILL SLOWLY
BUILD IN BEHIND THIS STORM FOR TUESDAY AND WEDNESDAY. ANOTHER COLD
FRONT WILL APPROACH THROUGH THURSDAY...AND PROVIDE THE RISK OF
RAIN FOR THE END OF THE WEEK.
&&
.NEAR TERM /UNTIL 6 AM MONDAY MORNING/...
WATER VAPOR LOOP SHOWS A VIGOROUS UPPER LOW TRANSLATING EAST OVER
THE MIDWEST. A DRY SLOT IS INTRUDING OVER THE TENNESSEE VALLEY.
ACARS 400-250MB WIND OBSERVATIONS SHOW A 110-150KT CYCLICALLY CURVED
JET FROM THE PLAINS INTO THE CENTRAL APPALACHIANS. 11Z SURFACE
ANALYSIS PLACED A 985MB OCCLUDED CYCLONE IN EAST CENTRAL ILLINOIS.
THE OCCLUDED BOUNDARY EXTENDED SOUTHEAST INTO NORTHERN
ALABAMA...WITH A COLD FRONT CONTINUING SOUTHWEST ACROSS SOUTHERN
TEXAS. A WARM/STATIONARY BOUNDARY STRETCHED EAST FROM CENTRAL
ALABAMA THROUGH SOUTHERN GEORGIA. RIDGING IS OCCURRING EAST OF THE
APPALACHIANS WITH A COASTAL BOUNDARY BEGINNING TO DEVELOP ALONG THE
EASTERN CAROLINAS. A PRE-FRONTAL TROUGH WAS NOTED 50-100 MILES AHEAD
OF THE OCCLUDED BOUNDARY.
CONVECTIVE LINE AHEAD OF UPPER LOW CURRENTLY APPROACHING THE
APPALACHIANS. 09Z SREF INDICATE GREATER ELEVATED INSTABILITY ALOFT
THIS EVENING THAN THE 03Z RUN...AND GIVEN CURRENT CG ACTIVITY...HAVE
ADDED THUNDER TO THE FORECAST. THE GREATEST FLASH FLOOD RISK IS LATE
THIS AFTERNOON THROUGH THE LATE EVENING AS CONVECTIVE ACTIVITY
STRATIFIES ACROSS THE REGION. AS THE UPPER LOW PASSES OVERHEAD
OVERNIGHT...EXPECT PRECIPITATION TO PIVOT WESTWARD (NORTH OF THE
UPPER LOW)...FOCUSING ACROSS THE NORTHERN ZONES. THIS WOULD
POTENTIALLY LEAD TO A MORE PROLONGED FLOOD THREAT.
SOUTHERN EDGE OF AFOREMENTIONED CONVECTIVE LINE HAS MADE A RUN TO
THE SOUTHEAST ACROSS SOUTHERN VIRGINIA TOWARD GREATER BOUNDARY LAYER
INSTABILITY. AT THIS TIME DO NOT EXPECT NORTHWARD EXPANSION OF
SEVERE WEATHER THREAT GIVEN THE TRACK OF THE TRIPLE POINT LOW.
&&
.SHORT TERM /6 AM MONDAY MORNING THROUGH WEDNESDAY NIGHT/...
LOPRES WL BE MVG OFF THE DELMARVA MON. HWVR...THE DEEP SYSTM WL BE
CAPABLE OF WRAPPING MSTR ARND ITS N SIDE AND BACK ACRS CWFA. THAT WL
PROVIDE A STRONG LIKLIHOOD OF PCPN CONTG INTO THE AFTN /ASSOC W/
DEFORMATION AXIS/...SPCLY ACRS THE NRN CWFA. RAFL RATES WONT BE
QUITE AS INTENSE AS TNGT...BUT PWAT JUST UNDER AN INCH COMBINED W/
STRONG UVVS...ENHANCED BY ERN SLOPES OF BLURDG...WL LEAD TO ANTHR
HALF INCH TO INCH OF RAFL. THE FLOW TURNS NLY W/ A GOOD P-GRAD
REMAINING...PROVIDING GOOD MIXING. THUS A COOL AND WINDY DAY...NOT
VERY MAY-LIKE. STAYED ON THE COOL SIDE OF GDNC /MAXT UPR 40S-MID
50S/.
WL BRING IN DRIER AIR ON W SIDE OF DEF AXIS MON NGT. ANY LINGERING
PCPN WL END ELY...AND STRONG NNW FLOW WL SCOUR OUT CLDS TWD MRNG.
HIPRES RDG WL WRK IN TUE-WED. WL KEEP THE WNDS UP TUE TIL P-GRAD CAN
TRULY SLACKEN. TEMPS WL REBOUND BASED MAINLY ON BETTER INSOLATION
/NOT MUCH OF AN ONGOING ADVECTIVE PTTN./ STILL...STAYED ON COOLER
END OF SPREAD...WHERE THERE WAS ONE.
&&
.LONG TERM /THURSDAY THROUGH SUNDAY/...
LOOKING LIKE ANTHR ACTV XTNDD PD...AS CDFNT APPROACHES THU. DESPITE
DIFFS...OVRALL AGREEMENT EXISTS TO BRING FRNT THRU SLOWLY ON THU...
AND DVLP SVRL WVS OF LOPRES ALNG IT THU NGT-SAT MRNG. ANTHR CDFNT WL
BE ON ITS HEELS FM THE W BY SUN. UNFORTUNATELY...WL NEED TO CARRY
CHC POPS THRU MUCH OF THE PD...PARTLY DUE TO UNCERTAINTY. THE BEST
WINDOW FOR DRY WX COMES SAT NGT...AFTER LAST WV TREKS OFFSHORE AND
BEFORE ANY ISENTROPIC LIFT CAN SLIDE EAST. TEMPS WL BE CLOSE TO
CLIMO FOR MINS...AND A TOUCH COOLER THAN AVG FOR MAXT...FITTING FOR
THE SMALLER DIURNAL RNG XPCTD DURING CLDY CONDS.
&&
.AVIATION /19Z SUNDAY THROUGH FRIDAY/...
HEAVY BAND OF RAIN WILL ENTER THE TERMINALS LATE THIS
AFTERNOON/EARLY THIS EVENING. EXPECT CEILINGS TO DROP TO IFR. GUSTY
SOUTHEAST WINDS WILL SWING OUT OF THE NORTH LATE TONIGHT AS STRONG
LOW PRESSURE PASSES TO THE EAST.
FLGT RESTRICTIONS /MVFR TO LCL IFR/ TO CONT MON...BUT WL IMPRV TO
AREAS MVFR AND THEN VFR TMRW NGT. XPCT VFR CONDS THRU WED...THEN
MVFR-LCL IFR THRU END OF WK.
&&
.MARINE...
GALE CONDITIONS EXPECTED AS SOUTHEASTERLY WINDS GUSTY AHEAD OF THE
NEXT SYSTEM THIS EVENING. LATER TONIGHT...WINDS SLACKEN OVER MUCH OF
THE AREA...EXCEPT BECOMING GUSTY OUT OF THE NORTH ACROSS THE
NORTHERN BAY...BASED ON THE CURRENT TRACK OF THE STRONG AREA OF LOW
PRESSURE.
STRONG WNDS RETURN TMRW AS DEFORMATION AXIS SWINGS THRU AND FLOW
BECOME NNWLY. PROFILES SUGGEST THAT WND GUSTS TO 35 KT LIKELY ACRS
MUCH OF THE MARINE AREA. UPR PTMC MAY NOT QUITE REACH THAT HIGH DUE
TO REDUCED MARINE TRAJECTORY. WNDS CONT INTO TUE TIL PGRAD CAN
RELAX. SCA LIKELY THRAFTR. WL HOLD OFF ON THAT HEADLINE FOR
SIMPLICITY /DONT WANT TOO MANY HAZARD HEADLINES TO WATER DOWN
IMPACT./
&&
.HYDROLOGY...
STORM TTL QPF OF 1 TO 3 INCHES XPCTD...HIEST ALONG SPINE OF BLURDG
AND IN NRN MD. WKNG TSRA TNGT CUD PRODUCE LCLLY HIER AMTS. FFG
VALUES LOW...SPCLY IN DC-BALT METRO CORRIDOR /1 HR AMTS ARND A HALF
INCH AND 12 HR AMTS ARND 1 INCH/. THAT SUGGESTS A HIGH FF/FLOOD
THREAT EXISTS THIS EVNG...BOTH FM THE URBAN AND SMALL STREAM/CREEK
STANDPOINT. THAT THREAT WL TRANSFORM INTO A RIVER FLOOD EVENT AS
WATER DRAINS INTO THE TRIBS MON AND ON TO THE MAINSTEMS RIVERS LATER
MON-MON NGT.
&&
.TIDES/COASTAL FLOODING...
WATER LEVELS ARE STILL RUNNING ABOUT A FOOT ABOVE NORMAL. WATER
LEVEL DEPARTURES ARE EXPECTED TO INCREASE TO 1 TO 2 FEET ABOVE
ASTRONOMICAL PREDICATIONS INTO MONDAY AS STRONG LOW PRESSURE
MOVES ACROSS THE CHESAPEAKE BAY. HAVE ISSUED A COASTAL FLOOD
ADVISORY ALONG THE WESTERN SHORE OF THE CHESAPEAKE BAY WHERE THE
STRONGEST AND MOST PERSISTENT FAVORABLE SOUTHEASTERLY FETCH WILL
TRAP WATER...DESPITE BEING AT A QUARTER MOON.
&&
.LWX WATCHES/WARNINGS/ADVISORIES...
DC...FLOOD WATCH FROM 6 PM EDT THIS EVENING THROUGH MONDAY
AFTERNOON FOR DCZ001.
MD...FLOOD WATCH THROUGH MONDAY MORNING FOR MDZ003-501-502.
FLOOD WATCH FROM 6 PM EDT THIS EVENING THROUGH MONDAY
AFTERNOON FOR MDZ004>007-009>011-013-014-016>018.
COASTAL FLOOD ADVISORY UNTIL 10 AM EDT MONDAY FOR MDZ007-011-
014-017-018.
VA...FLOOD WATCH THROUGH MONDAY MORNING FOR VAZ021-025>031-036>040-
050-051-056.
FLOOD WATCH FROM 6 PM EDT THIS EVENING THROUGH MONDAY
AFTERNOON FOR VAZ041-042-052>055-057.
WV...FLOOD WATCH THROUGH MONDAY MORNING FOR WVZ050>055-501>504.
MARINE...GALE WARNING UNTIL 2 PM EDT TUESDAY FOR ANZ530>534-537.
SMALL CRAFT ADVISORY FROM 10 PM THIS EVENING TO 2 PM EDT
TUESDAY FOR ANZ535-536.
GALE WARNING UNTIL 10 PM EDT THIS EVENING FOR ANZ535-536.
&&
$$
SYNOPSIS...HTS
NEAR TERM...ROGOWSKI
SHORT TERM...HTS
LONG TERM...HTS
AVIATION...ROGOWSKI/HTS
MARINE...ROGOWSKI/HTS
HYDROLOGY...HTS
TIDES/COASTAL FLOODING...ROGOWSKI
AREA FORECAST DISCUSSION
NWS BALTIMORE MD/WASHINGTON DC
1102 AM EDT SAT MAY 10 2008
.SYNOPSIS...
A WEAK AREA OF LOW PRESSURE WILL PASS BY TO OUR SOUTH EARLY THIS
AFTERNOON. HIGH PRESSURE WILL BUILD OVER THE MID-ATLANTIC TONIGHT.
THIS HIGH WILL MOVE OFF THE COAST SUNDAY AND THE NEXT STORM SYSTEM
WILL APPROACH FROM THE WEST. THIS STORM WILL SLOWLY PASS BY TO OUR
SOUTH SUNDAY NIGHT AND MONDAY BRINGING A GOOD CHANCE FOR
SIGNIFICANT RAIN. HIGH PRESSURE WILL RETURN FOR TUESDAY AND
WEDNESDAY.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
WATER VAPOR LOOP SHOWS A SHORT WAVE OVER SOUTHERN PENNSYLVANIA
LIFTING NORTHEAST...WITH RIDGING OCCURRING ACROSS THE CENTRAL CONUS
AHEAD OF THE DEVELOPING SYSTEM OVER THE ROCKIES. ACARS 400-250MB
WIND OBSERVATIONS SHOW A 100-140KT ANTICYCLONICALLY CURVED JET FROM
THE FOUR CORNERS REGION INTO THE CAROLINAS. 11Z SURFACE ANALYSIS
PLACED A 1005MB OCCLUDED CYCLONE NEAR CHARLOTTESVILLE...WITH
OCCLUSION FRONT SOUTH TO NEAR ATLANTA. THE BAROCLINIC ZONE RUNS EAST
ACROSS THE GULF STATES AND SOUTH CAROLINA. A 1015MB ANTICYCLONE
DOMINATES THE GREAT LAKES REGION.
SHORT WAVE IS LIFTING NORTHEAST INTO NEW ENGLAND...WITH DRYING
SEEN IN THE UPPER LEVELS ON WATER VAPOR IMAGERY. RAIN WILL
CONTINUE TO DIMINISH TO AREAS OF SPRINKLES AS A RESULT. KEPT IN A
30 POP FOR THOSE LOCATIONS WHICH MAY RECORD A HUNDRETH OR TWO
EARLY THIS AFTERNOON.
WINDS BECOME NORTHWESTERLY WITH THE PASSAGE OF THE OCCLUDED
BOUNDARY. CLOUDS EXPECTED TO GRADUALLY ERODE FROM SOUTHWEST TO
NORTHEAST AS ANTICYCLONIC FLOW ALOFT BEGINS TO SET UP. THIS WILL
ALLOW TEMPERATURES IN THE SOUTHWEST TO NEAR 70F...WITH LOCATIONS
CLOSER TO THE PA BORDER AND BAY STRUGGLING TO REACH 60F.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 AM SUNDAY/...
HIGH PRESSURE WILL CONTINUE TO BUILD OVERHEAD TONIGHT IN THE WAKE
OF LOW PRESSURE AT THE SURFACE...AND THE UPPER LEVEL DISTURBANCE.
SKIES WILL GRADUALLY IMPROVE TO MOSTLY CLEAR/PARTLY CLOUDY AND DRY
CONDITIONS ARE ANTICIPATED.
SREFS AND NUMERICAL GUIDANCE NOT SHOWING MUCH POTENTIAL FOR FOG
DEVELOPMENT OVERNIGHT. HOWEVER...IF THE NW WINDS COMPLETELY
DE-COUPLE...SOME PATCHY FOG IS LIKELY...ESPECIALLY WITH THE SATURATED
GROUND. OTHERWISE...THE MET NUMBERS LOOKED BETTER FOR THE
OVERNIGHT MINS.
&&
.LONG TERM /SUNDAY THROUGH FRIDAY/...
SURFACE HIGH WILL MOVE OFF THE COAST SUNDAY AND THE NEXT STORM
SYSTEM WILL APPROACH FROM THE WEST. THIS SYSTEM IS ALREADY SHOWING
UP ON THE SATELLITE IMAGERY AS IT MOVES INTO THE ROCKIES THIS
MORNING. AS THIS SYSTEM TRACKS THROUGH THE PLAINS LATER TODAY AND
TONIGHT IT WILL PHASE WITH NORTHERN BRANCH ENERGY FROM CANADA
CAUSING THIS SYSTEM TO DEEPEN RAPIDLY. GUIDANCE CONTINUES TO BE IN
VERY GOOD AGREEMENT IN BRINGING A CLOSED OFF 500MB LOW THROUGH THE
OHIO VALLEY SUNDAY AND ACROSS SOUTHERN VIRGINIA SUNDAY NIGHT BEFORE
SLOWLY MOVING OFF THE MID-ATLANTIC COAST MONDAY. THE TRACK OF THIS
SYSTEM WILL ALLOW FOR A COASTAL STORM TO DEVELOP JUST OFF THE NORTH
CAROLINA COAST BY SUNDAY NIGHT. GIVEN THE STRONG DYNAMICS WITH THE
UPPER-LEVEL LOW...THIS WILL BE AN ABNORMALLY STRONG COASTAL SYSTEM
FOR THIS TIME OF YEAR. 09Z SREF SHOW SURFACE PRESSURES WITH THE
COASTAL LOW BEING AROUND 3 TO 4 STANDARD DEVIATIONS BELOW NORMAL.
GIVEN THE STRONG DYNAMICS WITH THE SYSTEM AND THE FAVORED TRACK JUST
TO OUR SOUTH. THIS WILL COMBINE WITH PLENTY OF DEEP MOISTURE FROM
THE ATLANTIC TO BRING SIGNIFICANT RAINFALL TO THE REGION STARTING
LATER SUNDAY AND LASTING THROUGH MONDAY. AS OF NOW IT STILL APPEARS
THAT THE HEAVIEST RAIN WILL FALL SUNDAY NIGHT FOR MOST LOCATIONS.
GIVEN THE RECENT RAINFALL COMBINED WITH A POTENTIAL OF 1 TO 3 INCHES
OF RAIN WITH THIS SYSTEM DOES CAUSE MORE CONCERN FOR RIVER FLOODING
AND FLOODING OF SMALL STREAMS AND CREEKS SUNDAY NIGHT INTO EARLY
NEXT WEEK. FOR NOW...WILL MENTION IN THE HWO AND HOLD OFF ON A FLOOD
WATCH GIVEN THE FACT THAT IT IS STILL 48 HOURS OUT.
THE COASTAL STORM WILL SLOWLY DEPART MONDAY AND WINDY CONDITIONS ARE
EXPECTED BEHIND IT MONDAY AFTERNOON INTO MONDAY EVENING. HIGH
PRESSURE WILL RETURN FOR TUESDAY AND WEDNESDAY BRINGING A RETURN OF
DRY CONDITIONS. THE NEXT SYSTEM WILL ARRIVE FOR THE LATTER PART OF
THE WEEK WITH THE NEXT CHANCE FOR PRECIPITATION.
&&
.AVIATION /15Z SATURDAY THROUGH WEDNESDAY/...
MVFR CEILINGS MID MORNING EXPECTED TO IMPROVE INTO VFR AS MOISTURE
FROM THE LASTEST UPPER LEVEL DISTURBANCE MOVES OUT OF THE REGION.
WINDS STREGTHEN OUT OF THE NORTH AS HIGH PRESSURE BEGINS TO BUILD
IN. WITH SKIES CLEARING AND WINDS BECOMING LIGHT THIS
EVENING...WILL HAVE TO MONITOR FOR AREAS OF FOG DEVELOPMENT.
VFR CONDITIONS ARE EXPECTED TO START SUNDAY...BUT CONDITIONS WILL
DETERIORATE TO MVFR/IFR CIGS AND VSBYS AS THE AFTERNOON PROGRESSES.
MORE MVFR/IFR CIGS AND VSBYS ARE EXPECTED SUNDAY NIGHT INTO MONDAY
AS A POTENT STORM SYSTEM PASSES JUST SOUTH OF THE TERMINALS.
CONDITIONS WILL IMPROVE LATER MONDAY AFTERNOON AND MONDAY NIGHT AS
THE STORM SYSTEM DEPARTS...BUT GUSTY NORTH-NORTHWEST WINDS ARE
EXPECTED BEHIND THE STORM. HIGH PRESSURE WILL BRING A RETURN OF
TRANQUIL CONDITIONS FOR TUESDAY AND WEDNESDAY.
&&
.MARINE...
NORTHERLY FLOW INCREASES THIS AFTERNOON AS HIGH PRESSURE BEGINS TO
BUILD INTO THE REGION.
A SMALL CRAFT ADVISORY IS IN EFFECT FOR SUNDAY AND SUNDAY NIGHT. SMALL
CRAFT WINDS ARE EXPECTED FOR MONDAY INTO TUESDAY AS WELL.
DEPENDING ON THE EXACT TRACK AND STRENGTH OF THE STORM...A GALE
WARNING MAY BE WARRANTED SOMETIME LATE SUNDAY NIGHT THROUGH
MONDAY.
&&
.LWX WATCHES/WARNINGS/ADVISORIES...
DC...NONE.
MD...NONE.
VA...NONE.
WV...NONE.
MARINE...SMALL CRAFT ADVISORY FROM 12 PM SUNDAY TO 6 AM EDT MONDAY FOR
ANZ530>537.
&&
$$
SYNOPSIS...LASORSA
NEAR TERM...ROGOWSKI
SHORT TERM...LISTEMAA
LONG TERM...LASORSA
AVIATION...ROGOWSKI
MARINE...ROGOWSKI
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
631 AM CDT SAT MAY 10 2008
.DISCUSSION...
FORECAST CHALLENGES STILL CENTERED ON RAIN EVENT TODAY AND INTO
TOMORROW.
UPPER TROUGH VERY EVIDENT IN WATER VAPOR IMAGERY OVER THE NORTHERN
ROCKIES THIS MORNING...WITH LOOP CLEARLY SHOWING THAT IT IS STILL
DIGGING/DEEPENING. MOISTURE PLUME SEEN STREAMING INTO THE NORTHERN
PLAINS AND INTO WESTERN MINNESOTA/IOWA IN ADVANCE OF THE TROUGH.
NEAREST ECHOES ON THE 88D MOSAIC...IN THE WARM ADVECTION REGIME
AHEAD OF THE TROUGH...SEEN IN CENTRAL SOUTH DAKOTA NEAR PIERRE.
MODEL PROGS STILL SHOW THE BULK OF THIS DEVELOPING/ENTERING
WESTERN MINNESOTA AROUND 12Z /PER 295K ISENTROPIC SURFACE/...AND
SPREADING EASTWARD THROUGH THE MORNING HOURS. IT MAY TAKE AWHILE
FOR LOCATIONS IN WEST CENTRAL WISCONSIN TO SEE ANY MEASURABLE
RAINFALL...WITH LATEST TAMDAR SOUNDINGS AND THE 00Z KMPX RAOB
SHOWING A LOT OF DRY AIR IN THE LOW LEVELS. ONLY MINOR TWEAKS
WERE MADE TO THE INHERITED FORECAST...WITH LATEST MODEL RUNS AND
OBSERVATIONS SUPPORTIVE OF THE DEPICTED TIMING...AND POPS
ALREADY VERY HIGH.
AS THE SURFACE LOW DEEPENS ON ITS TREK THROUGH THE MID MISSISSIPPI
VALLEY...PARTS OF SOUTHERN MINNESOTA...ESPECIALLY...SHOULD SEE
BREEZY CONDITIONS TONIGHT. SPEEDS SHOULD REMAIN BELOW ADVISORY
CRITERIA...HOWEVER.
THINGS BEGIN TO DRY OUT FROM WEST TO EAST LATE TONIGHT /AFTER
MIDNIGHT/ AS THE UPPER LOW MOVES TOWARD THE OHIO VALLEY...TAKING
ITS WRAPAROUND MOISTURE WITH IT. WITH SUCH UNSEASONABLY COOL AIR
SPILLING INTO THE AREA BEHIND THE TROUGH...KEPT THE MENTION OF A
RAIN/SNOW MIX FOR PARTS OF WESTERN MINNESOTA AFTER MIDNIGHT
TONIGHT. IT STILL LOOKS LIKE THE FORECAST AREA SHOULD BE RAIN
FREE BY SUNDAY NIGHT...AS THE SURFACE RIDGE BUILDS IN. BENEATH THE
HIGH PRESSURE...TEMPERATURES WILL STILL BE WELL BELOW SEASONAL
NORMALS...DESPITE SOME RETURN FLOW LATE IN THE DAY OVER WESTERN
MINNESOTA.
BY THE BEGINNING OF THE WORK WEEK...OUR NEXT SYSTEM IS KNOCKING ON
OUR DOORSTEP...LEADING TO STRONG WARMING ON MONDAY...AND MORE
SEASONAL HIGHS. MODELS GENERALLY AGREE ON BRINGING THE COLD FRONT
THROUGH NORTHWEST MINNESOTA...AND NEAR THE FORECAST AREA...BY
TUESDAY MORNING. GREATER THREAT OF THUNDER WILL ACCOMPANY THIS
SYSTEM...WITH HIGHER DEW POINTS/INSTABILITY EXPECTED. REDUCED POPS
ON THE WESTERN EDGE FROM TUESDAY NIGHT AND INTO WEDNESDAY...WITH
MODELS DEPICTING A MORE RAPID FRONTAL PASSAGE.
&&
.AVIATION.../12Z TAF ISSUANCE/
LOW PRES CENTER OVER SE CO AND W KS WITH A TROF EXTENDING INTO SD
WL MV ENE TODAY SPREADING RAIN ACROSS THE AREA BEGINNING IN THE SW
MN THIS MORNING AND REACHING WESTERN WI DURING THE AFTERNOON. VFR
CEILINGS WILL LOWER TO MAINLY MVFR IN THE RAIN BUT A POSSIBLE
PERIOD OF IFR CEILINGS OVER SOUTH CENTRAL MN INCLUDING KRWF. VSBYS
WILL ALSO DROP TO MVFR IN RAIN. THE RAIN AND LOW CEILINGS SHOULD BEGIN
TO EXIT THE WESTERN CWA AROUND 08-09Z. N TO NE WINDS COULD GUST TO
AROUND 22 KNOTS WESTERN CWA AS THE LOW PUSHES THROUGH EASTERN IA.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
&&
$$
KAT/JPR
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
246 AM CDT SAT MAY 10 2008
.DISCUSSION...
FORECAST CHALLENGES STILL CENTERED ON RAIN EVENT TODAY AND INTO
TOMORROW.
UPPER TROUGH VERY EVIDENT IN WATER VAPOR IMAGERY OVER THE NORTHERN
ROCKIES THIS MORNING...WITH LOOP CLEARLY SHOWING THAT IT IS STILL
DIGGING/DEEPENING. MOISTURE PLUME SEEN STREAMING INTO THE NORTHERN
PLAINS AND INTO WESTERN MINNESOTA/IOWA IN ADVANCE OF THE TROUGH.
NEAREST ECHOES ON THE 88D MOSAIC...IN THE WARM ADVECTION REGIME
AHEAD OF THE TROUGH...SEEN IN CENTRAL SOUTH DAKOTA NEAR PIERRE.
MODEL PROGS STILL SHOW THE BULK OF THIS DEVELOPING/ENTERING
WESTERN MINNESOTA AROUND 12Z /PER 295K ISENTROPIC SURFACE/...AND
SPREADING EASTWARD THROUGH THE MORNING HOURS. IT MAY TAKE AWHILE
FOR LOCATIONS IN WEST CENTRAL WISCONSIN TO SEE ANY MEASURABLE
RAINFALL...WITH LATEST TAMDAR SOUNDINGS AND THE 00Z KMPX RAOB
SHOWING A LOT OF DRY AIR IN THE LOW LEVELS. ONLY MINOR TWEAKS
WERE MADE TO THE INHERITED FORECAST...WITH LATEST MODEL RUNS AND
OBSERVATIONS SUPPORTIVE OF THE DEPICTED TIMING...AND POPS
ALREADY VERY HIGH.
AS THE SURFACE LOW DEEPENS ON ITS TREK THROUGH THE MID MISSISSIPPI
VALLEY...PARTS OF SOUTHERN MINNESOTA...ESPECIALLY...SHOULD SEE
BREEZY CONDITIONS TONIGHT. SPEEDS SHOULD REMAIN BELOW ADVISORY
CRITERIA...HOWEVER.
THINGS BEGIN TO DRY OUT FROM WEST TO EAST LATE TONIGHT /AFTER
MIDNIGHT/ AS THE UPPER LOW MOVES TOWARD THE OHIO VALLEY...TAKING
ITS WRAPAROUND MOISTURE WITH IT. WITH SUCH UNSEASONABLY COOL AIR
SPILLING INTO THE AREA BEHIND THE TROUGH...KEPT THE MENTION OF A
RAIN/SNOW MIX FOR PARTS OF WESTERN MINNESOTA AFTER MIDNIGHT
TONIGHT. IT STILL LOOKS LIKE THE FORECAST AREA SHOULD BE RAIN
FREE BY SUNDAY NIGHT...AS THE SURFACE RIDGE BUILDS IN. BENEATH THE
HIGH PRESSURE...TEMPERATURES WILL STILL BE WELL BELOW SEASONAL
NORMALS...DESPITE SOME RETURN FLOW LATE IN THE DAY OVER WESTERN
MINNESOTA.
BY THE BEGINNING OF THE WORK WEEK...OUR NEXT SYSTEM IS KNOCKING ON
OUR DOORSTEP...LEADING TO STRONG WARMING ON MONDAY...AND MORE
SEASONAL HIGHS. MODELS GENERALLY AGREE ON BRINGING THE COLD FRONT
THROUGH NORTHWEST MINNESOTA...AND NEAR THE FORECAST AREA...BY
TUESDAY MORNING. GREATER THREAT OF THUNDER WILL ACCOMPANY THIS
SYSTEM...WITH HIGHER DEW POINTS/INSTABILITY EXPECTED. REDUCED POPS
ON THE WESTERN EDGE FROM TUESDAY NIGHT AND INTO WEDNESDAY...WITH
MODELS DEPICTING A MORE RAPID FRONTAL PASSAGE.
&&
.AVIATION.../06Z TAF ISSUANCE/
VFR CONDITIONS WILL PREVAIL OVERNIGHT AS SFC RIDGE MOVES SLOWLY
EAST. LOW PRESSURE SYSTEM OVER THE ROCKIES...WILL SLOWLY ADVANCES
EAST OVER THE MIDWEST DURING THE PERIOD. HOWEVER...THE BLOCKING
UPPER RIDGE DEVELOPING OR FORECAST TO AMPLIFY OVER THE EASTERN
CONUS...WILL DETER THE SYSTEM FROM ADVANCING TO QUICKLY OUT OF THE
MIDWEST THIS WEEKEND. THUS...CEILINGS/VISBILITIES LOWERED TO MVFR TO
IFR CONDITIONS IN PRECIP DURING THE REST OF THE PERIOD. LITTLE
IMPROVEMENT ANTICIPATED EXCEPT FOR THE FAR WESTERN TAF SITES LATE
SATURDAY NIGHT.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
&&
$$
KAT/JVM
AREA FORECAST DISCUSSION
NWS ALBUQUERQUE NM
258 AM MDT SAT MAY 10 2008
.DISCUSSION...
WATER VAPOR LOOP THIS MORNING SHOWS A SQUEEZE PLAY IN THE UPPER
ATMOSPHERE AS A SOUTHERN STREAM UPPER WAVE OVER NM SHEARS EAST
WHILE ANOTHER STRONGER WAVE SLIDES EAST ACROSS THE CENTRAL ROCKIES.
THE RESULT IS A 120-140 KNOT JET CORE STRETCHING FROM SW NM NE INTO
EASTERN KS AS EVIDENT ON THE 400-250MB ACARS PLOT. AT THE SURFACE A
997MB LOW PRESSURE CENTER IS CENTERED OVER SE CO WITH A COOL FRONT
MOVING SOUTH OVER THE FRONT RANGE. 00Z MODEL SUITE...INCLUDING THE
UKMET/ECMWF/GFS/NAM/GEM...INDICATE THE SURFACE FRONT WILL SHIFT SE
INTO OK WHILE THE MID LEVEL FRONT ASSOCIATED WITH THE CENTRAL
ROCKIES UPPER WAVE ALSO PUSHES SE ACROSS NM. THIS WILL ESSENTIALLY
COOL MAX TEMPS A FEW DEGREES OVER FRIDAY OVER THE EASTERN PLAINS.
SINCE HIGH CLOUDS WILL PUSH WELL EAST OF THE AREA TODAY THERE WILL
LIKELY BE SIMILAR TEMPS ACROSS THE WEST AS HEATING BALANCES WEAK
COLD AIR ADVECTION AT 700MB. EXPANDED RED FLAG WARNINGS INTO THE
NW AND WESTERN MTNS AS WELL AS THE RIO GRANDE VALLEY WITH NW FLOW
PATTERN USUALLY STRONGER THAN MOS NUMBERS IN THESE AREAS.
AS HIGH PRESSURE BUILDS ACROSS TEXAS SATURDAY NIGHT THE FRONTAL
BOUNDARY WILL CONTINUE PUSHING WEST TOWARD THE RIO GRANDE VALLEY
THROUGH SUNDAY MORNING. LIGHT/MODERATE EAST CANYON WINDS STILL
POSSIBLE IN THE RIO GRANDE VALLEY SUNDAY MORNING. LOW LEVEL RH
FIELDS SHOW THERE WILL BE A STRONG DENSITY GRADIENT ALONG THE
CENTRAL MTNS WITH THE FRONT THEREFORE LEFT GRIDS UNTOUCHED. THE
REMAINDER OF SUNDAY IS EXPECTED TO BE PLEASANT STATEWIDE. BIG
CHANGES POSSIBLE EARLY NEXT WEEK AS A STRONG UPPER LEVEL LOW
DEVELOPS OVER THE GREAT BASIN. STRONG WINDS AND CRITICAL FIRE
WEATHER APPEAR LIKELY FOR MONDAY STATEWIDE. CONCERNED WITH THE
TIMING AND INTENSITY OF THIS SYSTEM SINCE 21Z SREF/18Z MREF
GUIDANCE SHOWING THE GREATEST UNCERTAINTY WITH REGARD TO 500MB
HEIGHT FIELD EXISTS ON THE BACK EDGE OF THE UPPER LOW DEVELOPMENT
MONDAY INTO TUESDAY. AT THIS TIME IT APPEARS THE SYSTEM MAY DIG
FARTHER SOUTH INTO ARIZONA EARLY TUESDAY AND SLOW ITS PROGRESSION
EASTWARD THROUGH WEDNESDAY. THIS WOULD BE IN RESPONSE TO THE DEEP
AREA OF LOW PRESSURE DEVELOPING OFF THE EAST COAST ALLOWING FOR
STRONGER HEIGHT RISES OVER THE CENTRAL PLAINS THUS INCREASING THE
MERIDIONAL FLOW ACROSS THE CONUS. WITH REGARD TO GRID CHANGES
DECIDED TO GO ABOVE GUIDANCE MAX TEMPS MONDAY AND TUESDAY...DELAY
PRECIP ONSET OVER THE WEST TUESDAY...PUSH HIGHEST POPS INTO THE
CENTRAL PORTION OF THE STATE WEDNESDAY.
GUYER
&&
.AVIATION...
SURFACE COOL FRONT APPROACHING NORTHERN NEW MEXICO BORDER AT 09Z
SATURDAY WILL CONTINUE TO PUSH SOUTH AND EASTWARD THROUGH THE
STATE THROUGH 21Z SATURDAY. AT THE SAME TIME...SHORT WAVE TROUGH
TO SWING THROUGH E COLORADO AND WILL BRUSH NORTHCENTRAL/NORTHEAST
NEW MEXICO INCREASING WEST TO NORTHWEST GRADIENT ALOFT. THESE
FEATURES WILL RESULT IN GUSTY WEST TO NORTHWEST WINDS MOST LOCALES
THROUGH 00Z SUNDAY. OTRW ISOLD BRIEF MVFR/IFR CIGS/VSBY IN SHOWERS
NEAR THE COLORADO BORDER POSSIBLE THROUGH 21Z.
NEXT AVIATION DISCUSSION SCHEDULED FOR 21Z.
&&
.PRELIMINARY POINT TEMPS/POPS...
FARMINGTON...................... 73 34 82 43 / 0 0 0 0
GALLUP.......................... 71 28 80 35 / 0 0 0 0
GRANTS.......................... 72 29 78 37 / 0 0 0 0
GLENWOOD........................ 84 43 84 47 / 0 0 0 0
CHAMA........................... 63 23 71 34 / 5 0 0 0
LOS ALAMOS...................... 69 35 74 35 / 0 0 0 0
RED RIVER....................... 60 21 63 34 / 5 0 0 0
TAOS............................ 70 25 73 35 / 0 0 0 0
SANTA FE........................ 71 33 74 42 / 0 0 0 0
SANTA FE AIRPORT................ 74 35 77 44 / 0 0 0 0
ESPANOLA........................ 76 33 80 45 / 0 0 0 0
ALBUQUERQUE HEIGHTS............. 77 48 80 52 / 0 0 0 0
ALBUQUERQUE VALLEY.............. 80 45 82 54 / 0 0 0 0
ALBUQUERQUE FOOTHILLS........... 74 44 79 49 / 0 0 0 0
ALBUQUERQUE WEST MESA........... 79 46 81 50 / 0 0 0 0
SOCORRO......................... 84 48 84 55 / 0 0 0 0
SANDIA PARK/CEDAR CREST......... 69 35 73 45 / 0 0 0 0
MORIARTY/ESTANCIA............... 74 36 77 46 / 0 0 0 0
CARRIZOZO....................... 81 44 77 53 / 0 0 0 0
RUIDOSO......................... 72 40 70 50 / 0 0 0 0
RATON........................... 70 27 73 38 / 5 0 0 0
LAS VEGAS....................... 73 32 72 41 / 0 0 0 0
ROY............................. 72 34 73 46 / 0 0 0 0
CLAYTON......................... 72 36 74 46 / 5 0 0 0
SANTA ROSA...................... 82 39 78 46 / 0 0 0 0
TUCUMCARI....................... 83 41 79 51 / 0 0 0 0
FORT SUMNER..................... 85 44 78 47 / 0 0 0 0
CLOVIS.......................... 83 44 76 48 / 0 0 0 0
PORTALES........................ 85 42 77 47 / 0 0 0 0
ROSWELL......................... 94 49 79 51 / 0 0 0 0
&&
.ABQ WATCHES/WARNINGS/ADVISORIES...
RED FLAG WARNING FROM 10 AM THIS MORNING TO 7 PM MDT THIS EVENING
FOR THE FOLLOWING ZONES...NMZ101>108.
WIND ADVISORY FROM 10 AM THIS MORNING TO 7 PM MDT THIS EVENING FOR
THE FOLLOWING ZONES...NMZ011-012.
&&
$$
GUYER/99
AREA FORECAST DISCUSSION
NWS SEATTLE WA
1210 PM PDT SUN MAY 11 2008...UPDATED AVIATION SECTION
.SYNOPSIS...A COOL UPPER TROUGH WILL PRODUCE SCATTERED SHOWERS AND
SUN BREAKS ACROSS WESTERN WASHINGTON TODAY. A WEAK RIDGE WILL BUILD
INTO THE AREA MONDAY FOR A GENERALLY DRY DAY...WITH MORNING CLOUDS
GIVING WAY TO SOME AFTERNOON SUNSHINE. A WARM FRONT WILL BRING A
CHANCE OF RAIN TUESDAY. A STRONG UPPER RIDGE WILL BUILD OVER THE
PACIFIC NORTHWEST FOR WARM SUNNY DAYS WEDNESDAY THROUGH FRIDAY.
&&
.SHORT TERM...COULD BE THE LAST DUSTING OF SNOW IN THE CASCADES DOWN
TO PASS LEVEL TODAY WITH A COOL UPPER LEVEL TROUGH OVER THE REGION
TODAY. A LITTLE NEW SNOW ON THE TREES ON THE PASS WEBCAMS...MAINLY
ABOVE 3000FT. AN ACARS FREEZING LEVEL OVER SEATTLE AT 8AM WAS
3200FT...WITH A 700MB TEMP OF -11C AND -29C AT 500MB. SO THERE IS
JUST A SLIGHT CHANCE OF A THUNDERSTORM TODAY IN THE UNSTABLE AIR
MASS...WILL WATCH THE RADAR ECHO TOPS TODAY. AT 8AM THE PSCZ ONLY
HAS SHOWERS WITH TOPS TO 10 OR 15KFT...BUT THE PSCZ WILL SHIFT SOUTH
INTO KING COUNTY BY AFTERNOON AND DAYTIME INSOLATION COULD HELP FIRE
OFF A THUNDERSTORM. WILL HANDLE THAT WITH A NOWCAST OR TWO LATER IF
IT HAPPENS. ZONE FORECASTS ARE IN THE BALLPARK WITH HIGHEST POPS IN
THE PSCZ/NORTH OF SEATTLE WITH SCATTERED SHOWERS ELSEWHERE. NOT MUCH
IN THE WAY OF SHOWERS OUTSIDE THE PSCZ...BUT THE HEATING OF THE DAY
SHOULD FIRE OFF SCATTERED SHOWERS JUST ABOUT ANYWHERE OUTSIDE THE
PSCZ IN THE AFTERNOON. THE NAM CONTINUES TO FORECAST DRY WEATHER
MONDAY AND MONDAY NIGHT AS A WEAK RIDGE BUILDS IN...AND A WARM FRONT
ON TUESDAY IS LOOKING INCREASINGLY WET IN THE MODELS SO WE PROBABLY
WILL NOT GET BY WITH JUST A BRUSH BY/CHANCE OF RAIN FORECAST FOR
THAT DAY. WILL PROBABLY MOVE THE POPS WAY UP FOR TUESDAY AND TUESDAY
NIGHT AND EVEN KEEP A CHANCE OF RAIN OR DRIZZLE IN THE FORECAST FOR
WEDNESDAY MORNING. SEEMS LATE IN THE YEAR FOR A WARM FRONT TO BE SO
WET...BUT THAT IS WHAT THE MODELS SHOW. I DO THINK THAT WITH HEIGHTS
RISING TO 580-585DAM WEDNESDAY AFTERNOON THAT THE PRECIP WILL DRY UP
AROUND NOON AND MAX TEMPS WILL SPIKE NICELY INTO THE LOWER TO MID
70S BEHIND THE WARM FRONT IN CLEARING SKIES WED AFTERNOON. 19
.LONG TERM...THE 06Z GFS KEEPS THE STRONG WARM UPPER RIDGE OVER THE
REGION THROUGH FRIDAY AND THEN WEAKENS IT AND SHIFTS IT INLAND
SUNDAY...WITH HEIGHTS FALLING TO ARND 576DAM SUNDAY. THAT SUGGESTS A
MARINE PUSH SATURDAY NIGHT. I EXPECT TO SHOW TWO VERY WARM DAYS
THURSDAY AND FRIDAY...THEN DROP TEMPS JUST A LITTLE SATURDAY...AND
FURTHER INTO SUNDAY AS IT BECOMES INCREASINGLY LIKELY THAT MARINE
AIR WILL HAVE COOLED OFF WRN WA. HAVE ALREADY STARTED TO PUSH THE
GRIDS THAT WAY SO ADJACENT OFFICES CAN SEE THAT...AND IF THE 12Z GFS
AND ECMWF AGREE MAY EVEN ADD FIVE DEGREES TO THE CURRENT MAX TEMP
FORECASTS FOR THU/FRI. 19
&&
.AVIATION....UPDATED 19Z...RADAR/OBS INDICATE THE LEADING EDGE OF
THE CONVERGENCE ZONE NEAR OR OVER THE KBFI TERMINAL AT 19Z. WINDS
WILL GO VARIABLE AND SWITCH TO THE N/NE AT THE KBFI/KSEA TERMINALS
WITHIN THE NEXT COUPLE HOURS...A LITTLE SOONER THAN PREVIOUSLY
EXPECTED. TEMPO MVFR CONDS WITH HEAVIER RAIN BANDS. THE PSCZ ZONE
SHOULD WEAKEN AFTER MIDNIGHT BUT COULD LINGER NEAR THE KBFI/KSEA
TERMINALS OVERNIGHT...LIFTING BACK NWD TO AFFECT THE KPAE TERMINAL
TOWARD MORNING.
.SEA...THE PSCZ IS CURRENTLY NEAR KBFI AND SHOULD SLIDE SWD TO THE
KSEA TERMINAL BETWEEN 20-21Z. SW WIND 10-15 KT....BECOMING VARIABLE
ARND 10 KT OR LESS AFTER 20Z...THEN NE 5-8 KT BY 22Z. EXPECT MVFR
CONDS UNDER HEAVIER RAIN BANDS. DTM
&&
.MARINE...SLY GRADIENTS OVER THE INLAND WATERS ARE WEAKENING THIS
MORNING...BUT MODERATELY STRONG ONSHORE FLOW WILL CONTINUE TO
PRODUCE WLY SMALL CRAFT WINDS THROUGH THE STRAIT TODAY. WILL DROP
ADVISORIES FOR ADMIRALTY/PUGET SOUND. SEAS WILL BE COMING UP TO 10
FEET OR SO ON THE COASTAL WATERS THIS AFTERNOON AS WINDS ARE
DECREASING. GRAYS HARBOR BAR CONDITIONS BECOMING ROUGH DURING THE
EBBS. DTM
&&
.SEW WATCHES/WARNINGS/ADVISORIES...
.SMALL CRAFT ADVISORY FOR THE COAST...AND STRAIT OF JUAN DE FUCA.
.SMALL CRAFT ADVISORY FOR ROUGH GRAYS HARBOR BAR.
$$
WEATHER.GOV/SEATTLE
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