AREA FORECAST DISCUSSION
NWS SAN DIEGO CA
230 PM PDT FRI JUL 11 2008
.SYNOPSIS...
SUBTROPICAL MOISTURE IN MODERATE EASTERLY FLOW ALOFT WILL BRING
VARIABLE CLOUDINESS...WITH A CHANCE OF THUNDERSTORMS OVER THE
MOUNTAINS AND DESERTS THROUGH THE WEEKEND. THERE IS A SLIGHT
CHANCE OF SHOWERS DRIFTING ALL THE WAY TO THE COAST. TEMPERATURES
WILL BE NEAR SEASONAL AVERAGES. RATHER HUMID INLAND AREAS. A WEAK
TROUGH OF LOW PRESSURE MAY BRING SLOW DRYING EARLY NEXT WEEK.
&&
.DISCUSSION...FOR EXTREME SOUTHWESTERN CALIFORNIA INCLUDING ORANGE...
SAN DIEGO...WESTERN RIVERSIDE AND SOUTHWESTERN SAN BERNARDINO
COUNTIES...
.SHORT TERM (TODAY THROUGH SUNDAY)...
MID LEVEL MOISTURE IS STILL COPIOUS INDEED...AND THIS HAS DEFINITELY
HAD A SIGNIFICANT IMPACT ON INLAND TEMPS...ESPECIALLY IN THE
MOUNTAINS AND DESERTS WHERE TEMPS ARE RUNNING 10 TO 15 DEGREES COOLER
THAN YESTERDAY. THE COASTAL AREAS ARE THE EXCEPTION AS EAST FLOW HAS
SCOURED OUT THE MARINE LAYER...ALLOWING TEMPS TO INCREASE SLIGHTLY.
A FEW SPRINKLES ARE POSSIBLE JUST ABOUT ANYWHERE THIS AFTERNOON DUE
TO MOIST EAST FLOW ASSOCIATED WITH A NEARBY INVERTED TROUGH. THIS
INVERTED TROUGH IS FORECAST TO SLOWLY MOVE WESTWARD ACROSS THE
FORECAST AREA THROUGH SUNDAY...RESULTING IN A CONTINUOUS STREAM OF
MID/UPPER LEVEL MOISTURE AND AT LEAST A SLIGHT CHANCE TO CHANCE OF
PRECIPITATION AND/OR THUNDER MOST AREAS...BUT ESPECIALLY MOUNTAINS
AND DESERTS. CLOUD COVER AND THE STRENGTH OF MID LEVEL WINDS WILL
DETERMINE WHETHER THUNDERSTORMS BECOME WIDESPREAD ON SATURDAY OR
SUNDAY. THE MORE CLOUDS OVERHEAD...THE MORE STABLE THE ATMOSPHERE
BECOMES...THE LESS LIKELY CONVECTION WILL BECOME WIDESPREAD.
LIKEWISE...THE STRONGER THE MID LEVEL WINDS...THE MORE LIKELY
CONVECTION WILL BE SHEARED APART BEFORE STORMS CAN FORM. WOULD NOT
BE SURPRISED TO SEE AT LEAST ONE ACTIVE WEATHER DAY IN THE MOUNTAINS
AND DESERTS THIS WEEKEND...ESPECIALLY IF THE CLOUD COVER AND/OR MID
LEVELS WINDS DECREASE.
EAST FLOW ALOFT AND OUTFLOW FROM SHOWERS/THUNDERSTORMS TO OUR EAST
WILL RESULT IN A CHAOTIC MARINE LAYER THIS WEEKEND. FORECASTING LOW
CLOUDS ALONG THE COAST COULD BE SOMEWHAT TRICKY...BUT WITH ALL THE
ACTIVITY STREAMING IN FROM THE EAST...IT SEEMS LIKELY THAT THERE
WILL BE LESS IN THE WAY OF LOW MARINE LAYER CLOUDS AND MORE IN THE
WAY OF MID/HIGH LEVEL CLOUDS. MAX TEMPS WILL REMAIN AT OR SLIGHTLY
BELOW SEASONAL AVERAGES AS EXTENSIVE MID/HIGH LEVEL CLOUDS AND
MOISTURE CONTINUES TO MOVE IN FROM THE EAST. HOWEVER IT`S WORTH
MENTIONING THAT TEMPS COULD BE QUITE A BIT WARMER IF SUBSTANTIAL
BREAKS IN THE CLOUDS CAN DEVELOP.
&&
.LONG TERM (MONDAY THROUGH THURSDAY)...
LINGERING MID LEVEL MOISTURE WILL CONTINUE A SLIGHT CHANCE FOR
AFTERNOON THUNDERSTORMS OVER THE MOUNTAINS AND DESERTS MONDAY AND
POSSIBLY EVEN TUESDAY. A WEAK TROUGH OF LOW PRESSURE MAY BRING SLOW
DRYING BY MID WEEK WITH DECREASING THUNDERSTORM CHANCES IN THE
MOUNTAINS AND DESERTS AND LOWER HUMIDITIES FOR INLAND AREAS.
&&
.AVIATION...
111900Z...MDCRS SOUNDINGS CONTINUE TO SHOW THE MARINE LAYER ALONG
THE COAST TO BE 1400 FEET OR LOWER. MARINE LAYER IS VERY
DISORGANIZED IN RESPONSE TO THE EASTERLY FLOW ALOFT. STRATUS IS
CONFINED MAINLY TO THE COASTAL WATERS BUT COULD DRIFT OVER THE
COASTAL AIRPORTS FROM TIME TO TIME BUT NOT LIKELY TO BECOME CEILINGS
AT THOSE AIRPORTS AT LEAST THROUGH THE REMAINDER OF THE AFTERNOON.
CONFIDENCE IS LOW ON THE COASTAL AIRPORTS GETTING CEILINGS FROM
STRATUS TONIGHT BUT CAN NOT BE RULED OUT.
ABOVE THE MARINE LAYER...A MOIST EAST TO SOUTHEAST FLOW REMAINS IN
PLACE OVER THE AREA AND WILL KEEP VARIABLE AMOUNTS OF ALTOCU WITH
BASES AT OR ABOVE FL100 THROUGH SATURDAY. THE AIR MASS REMAINS
UNSTABLE ENOUGH FOR ISOLATED CBS/TSTMS OVER THE MOUNTAINS AND
DESERTS ESPECIALLY DURING THE AFTERNOONS BOTH DAYS. BASES OF CBS
COULD BE AROUND FL080 WITH TOPS TO FL400.
CLOUDS AND LOW LEVEL MOISTURE OVER THE DESERT AREAS SHOULD KEEP MAX
TEMPS AT KPSP AND KTRM NEAR 40C SATURDAY. KONT SHOULD BE AROUND 35C
ON SATURDAY. DISRUPTED MARINE LAYER COULD ALLOW TEMPS AT KSNA TO
REACH 25 TO 27C. HORTON
&&
.SGX WATCHES/WARNINGS/ADVISORIES...
CA...NONE.
PZ...NONE.
&&
$$
PUBLIC...SMALL/SCV
AVIATION/MARINE...HORTON
NWS ON THE WEB AT WEATHER.GOV/SANDIEGO
SOUTHWEST CALIFORNIA AREA FORECAST DISCUSSION
NWS LOS ANGELES/OXNARD CA
1215 PM PDT FRI JUL 11 2008
NEW AVIATION DISCUSSION
.SHORT TERM...
ACARS SOUNDINGS FROM KLAX SHOW A MUCH WEAKENED MARINE LAYER WHICH
TRANSLATED INTO A VERY SPARSE MARINE LAYER WITH MOST OF THE CLOUDS
IN THE MID LEVELS. PARTLY TO MOSTLY CLOUDY SKIES WILL CONTINUE
TODAY. BIG PROBLEM FOR THE DAY IS THE MID LEVEL CLOUDS WHICH WILL
RETARD MOUNTAIN HEATING AND COULD WORK AGAINST TSTM FORMATION. BUT
CONVECTION FORECAST STILL LOOKS ON TRACK WITH CHC TO SLGT CHC AS THE
MOISTURE IS IN PLACE AND IT WILL ONLY TAKE A LITTLE SHORT WAVE TO
INITIATE CONVECTION. WILL ONLY UPDATE TO INCREASE CLD WORDING AND
KNOCK DOWN MTN TEMPS A LITTLE.
...FROM PREVIOUS DISCUSSION...
MID AND UPPER LEVEL MOISTURE HAS INCREASED SIGNIFICANTLY ACROSS THE
FCST AREA...ESPECIALLY ACROSS LOS ANGELES AND ERN VTU COUNTIES.
STRATUS FIELD HAS BEEN DISRUPTED ACROSS L.A. AND VTU COUNTIES...
WHILE STRATUS WAS WDSPRD ACROSS CSTL SXNS OF SBA AND SLO COUNTIES.
MAIN FCST PROBLEM FOR THE NEXT FEW DAYS WILL BE THE THREAT OF
SHOWERS AND THUNDERSTORMS AS MONSOONAL PUSH EXPANDS INTO THE AREA.
THE GFS SEEMS TO BE DOING A BETTER JOB HANDLING THIS MOISTURE ACROSS
THE SWRN STATES. FOR TODAY...IT APPEARS THAT THE BEST THREAT OF
SHOWERS AND THUNDERSTORMS WILL BE ACROSS THE MTNS OF L.A...VTU AND
ERN SBA COUNTIES...AND THE ANTELOPE VALLEY. WITH WEAK E TO NELY FLOW
AT MID LVLS...IT IS POSSIBLE THAT SOME SHOWERS/STORMS COULD PUSH
INTO CSTL AND VLY AREAS OF L.A. AND VTU COUNTIES...AND INTO THE
CUYAMA VALLEY AND SRN INTERIOR VLYS OF SLO COUNTY. WITH SUCH WEAK
FLOW ALF...ANY THUNDERSTORMS WILL BE SLOW MOVING...WHICH WILL RAISE
THE CONCERN FOR FLASH FLOODING. ALTHOUGH PRECIPITABLE WATER VALUES
INCREASE TODAY...THE BULK OF THE MOISTURE WAS ABOVE 650 MB...SO HAVE
DECIDED TO HOLD OFF FROM ISSUING ANY FLASH FLOOD WATCHES FOR TODAY.
HOWEVER...THAT WILL HAVE TO BE MONITORED CLOSELY...ESPECIALLY FOR
THE MTNS OF L.A. AND VTU COUNTIES AND THE ANTELOPE VALLEY. TEMPS
WILL BE DOWN A FEW MORE DEGREES IN THE MTNS AND DSRTS TODAY...WITH
MOSTLY MINOR CHANGES IN CSTL AND VLY AREAS.
MONSOONAL MOISTURE WILL OVERSPREAD THE FCST AREA TONIGHT AND
SATURDAY...ALL THE WHILE INCREASING IN DEPTH AND MAGNITUDE. A VORT
LOBE ROTATING TOWARD THE FCST AREA FROM THE SE ON SATURDAY SHOULD
INCREASE THE THREAT OF SHOWERS AND TSTMS ACROSS THE ENTIRE AREA.
PRECIPITABLE WATER VALUES CONT TO INCREASE...AND ALTHOUGH E TO SELY
MID LVL FLOW INCREASES SLIGHTLY...IT STILL WILL BE RATHER WEAK...AND
FLASH FLOOD WATCHES WILL HAVE TO BE CONSIDERED FOR SAT. WHILE
ADDITIONAL COOLING IS EXPECTED IN THE MTNS AND DSRTS ON SAT...TEMPS
MAY EDGE UPWARD IN CSTL AND VLY AREAS AS ONSHORE FLOW WEAKENS.
MARINE LAYER WILL LIKELY BE DISRUPTED...WITH JUST PATCHY
NIGHT/MORNING LOW CLOUDS AND FOG IN CSTL AREAS.
FAIRLY DEEP MOISTURE WILL REMAIN IN PLACE ACROSS THE AREA SAT NIGHT
AND SUN...AND ANOTHER UPPER LEVEL IMPULSE WILL MOVE SLOWLY ACROSS
THE REGION. SKIES SHOULD VARY FROM PTLY TO MOSTLY CLDY SAT NIGHT AND
SUNDAY...WITH A CONTD CHANCE OF SHOWERS AND TSTMS JUST ABOUT
ANYWHERE. ONCE AGAIN...WEAK MID AND UPPER LEVEL FLOW WILL MAKE
FOR SLOW MOVING STORMS...AND WITH HIGH PRECIPITABLE WATER VALUES
ACROSS THE AREA...LOCALLY HEAVY RAINS AND FLASH FLOODING WILL REMAIN
A CONCERN. IT SHOULD BE STRESSED THAT WHILE THERE IS A CHANCE OR
SLIGHT CHANCE OF SHOWERS/TSTMS ACROSS THE ENTIRE FCST AREA SAT THRU
SUN...THE VAST MAJORITY OF THAT TIME WILL BE RAIN FREE.
.LONG TERM...ENOUGH MOISTURE WILL LINGER ON MONDAY TO KEEP A
SLIGHT CHANCE OF SHOWERS AND TSTMS FOR PORTIONS OF THE FCST
AREA. FOR NOW...POPS ARE CONFINED TO THE MTNS AND DESERTS...BUT A
LOOK AT THE 06Z RUN OF THE GFS SHOWS THAT MID LVL FLOW WILL BE
RATHER SLOW TO TURN SWLY...AND POPS MAY HAVE TO BE EXPANDED TO THE
REST OF THE AREA. THE LATEST GFS SHOWS SWLY FLOW ALF INCREASING
ACROSS THE AREA TUE WHICH SHOULD FINALLY PUSH THE MSTR TO THE E OF
THE REGION. HEIGHTS WILL BEGIN TO RISE ACROSS THE AREA BY WED AS AN
UPPER HIGH STRENGTHENS IN THE SWRN STATES...BUT A WEAK UPPER LOW
JUST OFF THE CST WILL PROBABLY KEEP TEMPS FROM SOARING TOO MUCH
ABOVE NORMAL. STRATUS SHOULD BEGIN TO REORGANIZE...SO THERE SHOULD
BE AT LEAST SOME NIGHT THRU MORNING LOW CLOUDS AND FOG AT LEAST
ACROSS THE CST PLAIN TUE THRU THU.
&&
.AVIATION...11/1915Z.
THE MARINE LAYER CLEARED VERY QUICKLY IN MOST AREAS THIS
MORNING...EXCEPT ALONG THE CENTRAL COAST WHERE THE MARINE CLOUDS
WERE JUST NOW CLEARING FROM THE COASTAL TAF SITES. THE MARINE CLOUD
FORECAST FOR TONIGHT IS A LOW CONFIDENCE FORECAST DUE TO THE INFLUX
OF MID LEVEL MOISTURE ACROSS THE AREA. DECIDED TO PUSH BACK THE LOW
CLOUD ONSET BUT THERE IS ALSO A POSSIBILITY THAT THE LOW CLOUDS WILL
NOT MAKE IT AT ALL. THERE WILL ALSO BE A SLIGHT CHANCE OF A SHOWER
OR THUNDERSTORM...NOT CURRENTLY INCLUDED IN THE TAFS.
KLAX...PARTLY CLOUDY SKIES THROUGH THIS EVENING...FOLLOWED BY LOW
CLOUDS AND FOG AFTER MIDNIGHT...FOLLOWED BY PARTLY CLOUDY SKIES
SATURDAY MORNING THROUGH AFTERNOON WITH A SLIGHT CHANCE OF A SHOWER
OR THUNDERSTORM. A FAIRLY LOW CONFIDENCE FORECAST.
KBUR...PARTLY CLOUDY WITH A SLIGHT CHANCE OF A SHOWER OR
THUNDERSTORM THROUGH SAT.
&&
.LOX WATCHES/WARNINGS/ADVISORIES...
NONE
&&
$$
PUBLIC...BRUNO/ASR
AVIATION...SWEET
WWW.WEATHER.GOV/LOSANGELES
SOUTHWEST CALIFORNIA AREA FORECAST DISCUSSION
NWS LOS ANGELES/OXNARD CA
930 AM PDT FRI JUL 11 2008
.SHORT TERM...
ACARS SOUNDINGS FROM KLAX SHOW A MUCH WEAKENED MARINE LAYER WHICH
TRANSLATED INTO A VERY SPARSE MARINE LAYER WITH MOST OF THE CLOUDS
IN THE MID LEVELS. PARTLY TO MOSTLY CLOUDY SKIES WILL CONTINUE
TODAY. BIG PROBLEM FOR THE DAY IS THE MID LEVEL CLOUDS WHICH WILL
RETARD MOUNTAIN HEATING AND COULD WORK AGAINST TSTM FORMATION. BUT
CONVECTION FORECAST STILL LOOKS ON TRACK WITH CHC TO SLGT CHC AS THE
MOISTURE IS IN PLACE AND IT WILL ONLY TAKE A LITTLE SHORT WAVE TO
INITIATE CONVECTION. WILL ONLY UPDATE TO INCREASE CLD WORDING AND
KNOCK DOWN MTN TEMPS A LITTLE.
...FROM PREVIOUS DISCUSSION...
MID AND UPPER LEVEL MOISTURE HAS INCREASED SIGNIFICANTLY ACROSS THE
FCST AREA...ESPECIALLY ACROSS LOS ANGELES AND ERN VTU COUNTIES.
STRATUS FIELD HAS BEEN DISRUPTED ACROSS L.A. AND VTU COUNTIES...
WHILE STRATUS WAS WDSPRD ACROSS CSTL SXNS OF SBA AND SLO COUNTIES.
MAIN FCST PROBLEM FOR THE NEXT FEW DAYS WILL BE THE THREAT OF
SHOWERS AND THUNDERSTORMS AS MONSOONAL PUSH EXPANDS INTO THE AREA.
THE GFS SEEMS TO BE DOING A BETTER JOB HANDLING THIS MOISTURE ACROSS
THE SWRN STATES. FOR TODAY...IT APPEARS THAT THE BEST THREAT OF
SHOWERS AND THUNDERSTORMS WILL BE ACROSS THE MTNS OF L.A...VTU AND
ERN SBA COUNTIES...AND THE ANTELOPE VALLEY. WITH WEAK E TO NELY FLOW
AT MID LVLS...IT IS POSSIBLE THAT SOME SHOWERS/STORMS COULD PUSH
INTO CSTL AND VLY AREAS OF L.A. AND VTU COUNTIES...AND INTO THE
CUYAMA VALLEY AND SRN INTERIOR VLYS OF SLO COUNTY. WITH SUCH WEAK
FLOW ALF...ANY THUNDERSTORMS WILL BE SLOW MOVING...WHICH WILL RAISE
THE CONCERN FOR FLASH FLOODING. ALTHOUGH PRECIPITABLE WATER VALUES
INCREASE TODAY...THE BULK OF THE MOISTURE WAS ABOVE 650 MB...SO HAVE
DECIDED TO HOLD OFF FROM ISSUING ANY FLASH FLOOD WATCHES FOR TODAY.
HOWEVER...THAT WILL HAVE TO BE MONITORED CLOSELY...ESPECIALLY FOR
THE MTNS OF L.A. AND VTU COUNTIES AND THE ANTELOPE VALLEY. TEMPS
WILL BE DOWN A FEW MORE DEGREES IN THE MTNS AND DSRTS TODAY...WITH
MOSTLY MINOR CHANGES IN CSTL AND VLY AREAS.
MONSOONAL MOISTURE WILL OVERSPREAD THE FCST AREA TONIGHT AND
SATURDAY...ALL THE WHILE INCREASING IN DEPTH AND MAGNITUDE. A VORT
LOBE ROTATING TOWARD THE FCST AREA FROM THE SE ON SATURDAY SHOULD
INCREASE THE THREAT OF SHOWERS AND TSTMS ACROSS THE ENTIRE AREA.
PRECIPITABLE WATER VALUES CONT TO INCREASE...AND ALTHOUGH E TO SELY
MID LVL FLOW INCREASES SLIGHTLY...IT STILL WILL BE RATHER WEAK...AND
FLASH FLOOD WATCHES WILL HAVE TO BE CONSIDERED FOR SAT. WHILE
ADDITIONAL COOLING IS EXPECTED IN THE MTNS AND DSRTS ON SAT...TEMPS
MAY EDGE UPWARD IN CSTL AND VLY AREAS AS ONSHORE FLOW WEAKENS.
MARINE LAYER WILL LIKELY BE DISRUPTED...WITH JUST PATCHY
NIGHT/MORNING LOW CLOUDS AND FOG IN CSTL AREAS.
FAIRLY DEEP MOISTURE WILL REMAIN IN PLACE ACROSS THE AREA SAT NIGHT
AND SUN...AND ANOTHER UPPER LEVEL IMPULSE WILL MOVE SLOWLY ACROSS
THE REGION. SKIES SHOULD VARY FROM PTLY TO MOSTLY CLDY SAT NIGHT AND
SUNDAY...WITH A CONTD CHANCE OF SHOWERS AND TSTMS JUST ABOUT
ANYWHERE. ONCE AGAIN...WEAK MID AND UPPER LEVEL FLOW WILL MAKE
FOR SLOW MOVING STORMS...AND WITH HIGH PRECIPITABLE WATER VALUES
ACROSS THE AREA...LOCALLY HEAVY RAINS AND FLASH FLOODING WILL REMAIN
A CONCERN. IT SHOULD BE STRESSED THAT WHILE THERE IS A CHANCE OR
SLIGHT CHANCE OF SHOWERS/TSTMS ACROSS THE ENTIRE FCST AREA SAT THRU
SUN...THE VAST MAJORITY OF THAT TIME WILL BE RAIN FREE.
.LONG TERM...ENOUGH MOISTURE WILL LINGER ON MONDAY TO KEEP A
SLIGHT CHANCE OF SHOWERS AND TSTMS FOR PORTIONS OF THE FCST
AREA. FOR NOW...POPS ARE CONFINED TO THE MTNS AND DESERTS...BUT A
LOOK AT THE 06Z RUN OF THE GFS SHOWS THAT MID LVL FLOW WILL BE
RATHER SLOW TO TURN SWLY...AND POPS MAY HAVE TO BE EXPANDED TO THE
REST OF THE AREA. THE LATEST GFS SHOWS SWLY FLOW ALF INCREASING
ACROSS THE AREA TUE WHICH SHOULD FINALLY PUSH THE MSTR TO THE E OF
THE REGION. HEIGHTS WILL BEGIN TO RISE ACROSS THE AREA BY WED AS AN
UPPER HIGH STRENGTHENS IN THE SWRN STATES...BUT A WEAK UPPER LOW
JUST OFF THE CST WILL PROBABLY KEEP TEMPS FROM SOARING TOO MUCH
ABOVE NORMAL. STRATUS SHOULD BEGIN TO REORGANIZE...SO THERE SHOULD
BE AT LEAST SOME NIGHT THRU MORNING LOW CLOUDS AND FOG AT LEAST
ACROSS THE CST PLAIN TUE THRU THU.
&&
.AVIATION...11/1130Z.
LOW CLOUDS HAVE SCOURED OUT OF VALLEYS AND COASTAL AREAS S OF SANTA
BARABARA COUNTY THIS MORNING. THIS LARGELY WAS DUE TO OUTFLOW FROM
EARLIER THUNDERSTORMS EAST OF THE FORECAST AREA CAUSING HAVOC ON LOW
CLOUD REGIME. LOW CLOUDS HAVE PUSHED WELL OFF THE LA/VTU COUNTY
COAST THIS MORNING. HOWEVER...LIFR/IFR CIGS REMAIN ACROSS THE SBA
SOUTH COAST THIS MORNING...AND SHOULD STICK AROUND THROUGH AT LEAST
EARLY AFTERNOON HOURS DUE TO STRONG LAX-BFL ONSHORE PUSH. LOW CLOUDS
COULD PUSH INLAND LATE AFTERNOON TO EARLY EVENING ACROSS LA/VTU
COUNTY COASTAL AREAS DUE TO STRONG ONSHORE FLOW...BUT CONFIDENCE IS
LOW WITH THIS DUE TO MID LVL MOISTURE OVERHEAD. LIFR/IFR CIGS ACROSS
CENTRAL COAST SHOULD CLEAR OFF THE COAST BY 16Z WITH LOW CLOUDS
BECOMING VFR CONDS LATE MORNING TO EARLY AFTERNOON. MONSOONAL
MOISTURE WILL CONTINUE TO STREAM IN FROM THE EAST TODAY BRINGING A
CHANCE OF SHOWERS AND THUNDERSTORMS ACROSS THE MOUNTAINS OF
LA/VTU/SBA AND THE SOUTHERN PORTION OF THE SLO MOUNTAINS AS WELL AS
THE ANTELOPE VALLEY THIS AFTERNOON. SOME UDDF WILL BE POSSIBLE NEAR
STRONGEST STORMS.
KLAX...PARTLY TO MOSTLY CLOUDY MID LEVEL CLOUDS TODAY. MID LEVEL
MOISTURE COULD IMPEDE THE STRATUS FROM FORMING THIS EVENING.
KBUR...HIGH CONFIDENCE WITH VFR CONDS TODAY. SOME BUILDING CU AND A
CHANCE OF TSTMS WITH MDT UDDFS OVER THE ADJACENT FOOTHILLS. MARINE
STATUS UNLIKELY TONIGHT.
&&
.LOX WATCHES/WARNINGS/ADVISORIES...
NONE
&&
$$
PUBLIC...BRUNO/ASR
AVIATION...KAPLAN/ASR
WWW.WEATHER.GOV/LOSANGELES
AREA FORECAST DISCUSSION
NWS WICHITA KS
1038 AM CDT THU JUL 10 2008
.UPDATE...
COUPLE OF UPDATES ALREADY HAVE BEEN MADE TO GRIDS. THERE APPEARS TO
BE A BIT MORE SUPPORT FOR PRECIPITATION ACROSS THE AREA TODAY AS
COMPARED TO YESTERDAY. WATER VAPOR LOOP/PROFILERS/ACARS DATA
SUGGEST A RIPPLE IN UPPER FLOW IS MOVING ACROSS SOUTHWEST KS AT
THIS TIME. PRECIPITATION IS DEVELOPING/EXPANDING IN ADVANCE OF THIS
FEATURE. RADAR LOOP ALSO SUGGEST SMALL MVC ABOUT HALF WAY BETWEEN
DDC AND AVK. HAVE BUMPED UP PROBABILITY OF PRECIPITATION GENERALLY
SOUTH OF HIGHWAY 54/400 AND INCREASED CLOUDS. WITH ADDITIONAL
CLOUDS...HAVE TRIMMED BACK ON MAXES. TOP 1200 UTC SOUNDING WAS
CONSIDERABLY DRIER THAN SGF...SO THERE WILL LIKELY BE A FAIRLY
SHARP CUTOFF SOMEWHERE ON THE NORTHERN EXTENT OF PRECIPITATION.
-HOWERTON
&&
.AVIATION...
FOR UPCOMING 18Z TAFS...MAIN CONCERNS WILL BE EXTENT OF PRECIPITATION
TODAY AND IMPACT ON CEILINGS. SOME IFR CEILINGS HAVE FLIRTED
WITH SOUTHEAST KS THIS MORNING. SIMILAR TO PREVIOUS DAYS...VFR
LIKELY EXCEPT IN CORES OF HEAVIER PRECIPITATION...WHERE BRIEF
IFR CONDITIONS ARE LIKELY. SUSPECT PRECIPITATION WILL WANE THIS
EVENING WITH BOTH LOSS OF HEATING AND PASSAGE OF SHORTWAVE.
-HOWERTON
&&
.PREV DISCUSSION... /ISSUED 636 AM CDT THU JUL 10 2008/
AVIATION...
FOR 12Z TAFS...MAIN AVIATION CONCERN WILL BE SHOWER AND STORM
CHANCES DURING THE DAY.
SHALLOW FOG AFFECTING KHUT AND KCNU WILL BE SHORT LIVED AND NOT
EXPECTED TO PERSIST TOO MUCH PAST 12Z AS THE BOUNDARY LAYER QUICKLY
WARMS.
AREA OF SHOWERS AND STORMS ALONG THE KS/OK BORDER WILL CONTINUE TO
SLOWLY PUSH EAST AND SLIGHTLY NORTHEAST TODAY. FOR NOW ONLY PUT VCTS
IN FOR KICT AND KCNU WITH LOW CONFIDENCE IN HOW FAR NORTH THIS
ACTIVITY WILL MAKE IT. THE GFS IS CURRENTLY DOING THE BETTER JOB
WITH THIS ACTIVITY AND IT REALLY DOES NOT BRING QPF TOO FAR NORTH.
LOW PRESSURE WILL STRENGTHEN OVER THE HIGH PLAINS OVERNIGHT ALLOWING
SOUTH WINDS TO REMAIN UP ACROSS THE AREA LIMITING ANY FOG POTENTIAL.
LAWSON
PREV DISCUSSION... /ISSUED 251 AM CDT THU JUL 10 2008/
DISCUSSION...
MAIN FORECAST CHALLENGE IS THUNDERSTORM CHANCES TODAY INTO THE
WEEKEND...AND TO A LESSER EXTENT TEMPERATURES IN THE NEAR TERM.
TODAY-FRIDAY:
WV IMAGERY/WIND PROFILERS DEPICT A MID-LEVEL DEFORMATION ZONE FROM
NW OK/SWRN KS INTO THE TX/OK PANHANDLES EARLY THIS AM. MODELS
SUGGEST THIS FEATURE WILL DRIFT SLIGHTLY NWD THIS AM...THEN EWD
ACROSS SRN KS/OK DURING THE AFTERNOON HOURS. AN INCREASE IN DEEP
LAYER MOISTURE WILL OCCUR FROM THE SW AND WITH MID-LEVEL
TEMPERATURES STILL RELATIVELY COOL FOR JULY STANDARDS...WILL NEED TO
CARRY CHANCE OF SHOWERS/T-STORMS EVEN WITH NO APPARENT LOW-LEVEL
BOUNDARIES AS A FOCUS. HIGHER POPS (~40%) WILL BE TOWARD THE OK
BORDER...WITH SLIGHTS (15-20%) FURTHER N. AS A RESULT OF ANTICIPATED
CLOUD COVER AND DEEPER MOISTURE...SLANTED HIGHS TOWARD COOLER MET
MOS IN THE SOUTH. EXPECTING CONVECTION TO ONCE AGAIN BE DIURNALLY
DRIVEN SO DID NOT INCLUDE POPS TONIGHT AFTER 01Z. ON FRIDAY...A
STRONG UPPER LOW (OVER BRITISH COLUMBIA EARLY THIS AM) WILL SWEEP
ACROSS THE NRN ROCKIES/NRN PLAINS. AHEAD OF THE ASSOCIATED COLD
FRONT...S-SWRLY WINDS WILL INCREASE TO BREEZY/WINDY CATEGORY
AREAWIDE. LOW-MID LEVEL THICKNESSES PROGGED TO INCREASE SO FRIDAY
LOOKS A FEW-SEVERAL DEGREES WARMER GIVEN DECENT INSOLATION IN THE PM.
FRIDAY NIGHT-TUESDAY:
THE STRONG UPPER LOW WILL REACH ONTARIO BY LATE SATURDAY AND THE
GFS/ECMWF/UKMET HAVE TRENDED SLIGHTLY FASTER WITH THE ASSOCIATED
COLD FRONTAL PASSAGE FOR OUR AREA OVER THE PAST FEW DAYS. THE FRONT
SHOULD MOVE THRU CNTRL KS FRI NIGHT...AND OUT OF FAR SERN KS BY LATE
SAT NIGHT. WITH MID-LEVEL TEMPERATURES REMAINING MODERATELY
WARM...UPPER FORCING LACKING...CONVECTION CHANCES LOOK LOW END
(15-30%) BUT NEVERTHELESS PRESENT AS THE FRONT MOVES THROUGH.
GIVEN THE STRENGTH OF THE UPPER TROF PASSING BY TO OUR N-NE...THE
00Z GFS MAY BE CORRECT (AT LEAST FOR NWRN PART OF KS) IN PROGGING
MUCH DRIER AIR PUSHING IN BEHIND THE FRONT THIS WEEKEND. HIGHS
LOOK SLIGHTLY BELOW NORMAL THIS WEEKEND BEHIND FRONT. THEN THE
MODELS INDICATE HEIGHTS WILL RISE IN THE MID-UPPER LEVELS EARLY-
MIDWEEK NEXT WEEK...LIKELY RESULTING IN TEMPERATURES WARMING TO
MORE NORMAL READINGS (LO-MID 90S) FOR MID JULY. MID-LEVEL
BAROCLINIC ZONE OVER THE KS REGION AND SWRLY LOW-LEVEL JET AT
NIGHT COULD PRODUCE SOME LATE NIGHT/AM CONVECTION SUN NIGHT INTO
TUESDAY.
JMC
&&
.PRELIMINARY POINT TEMPS/POPS...
WICHITA-KICT 82 72 93 73 / 30 10 10 10
HUTCHINSON 86 71 94 70 / 20 10 10 10
NEWTON 85 72 93 70 / 20 10 10 10
ELDORADO 84 71 92 71 / 30 10 10 10
WINFIELD-KWLD 81 71 93 73 / 60 10 10 10
RUSSELL 92 72 96 65 / 20 10 10 20
GREAT BEND 88 72 96 67 / 20 10 10 20
SALINA 93 72 95 68 / 20 10 10 20
MCPHERSON 88 71 94 69 / 20 10 10 20
COFFEYVILLE 82 70 91 73 / 80 10 10 10
CHANUTE 85 69 91 73 / 40 10 10 10
IOLA 85 69 91 73 / 30 10 10 10
PARSONS-KPPF 83 70 91 73 / 80 10 10 10
&&
.ICT WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION...UPDATED
NWS BALTIMORE MD/WASHINGTON DC
736 PM EDT FRI JUL 11 2008
.SYNOPSIS...
HIGH PRESSURE OVER THE MID-ATLANTIC WILL DRIFT OFF THE COAST
SATURDAY. A COLD FRONT WILL APPROACH THE REGION SLOWLY ON SUNDAY
BEFORE PASSING THROUGH MONDAY...BRINGING A CHANCE FOR SHOWERS AND
THUNDERSTORMS. HIGH PRESSURE WILL BUILD ACROSS THE MID-ATLANTIC
FOR THE MIDDLE OF NEXT WEEK.
&&
.NEAR TERM /UNTIL 6 AM SATURDAY MORNING/...
WATER VAPOR LOOP SHOWS AN UPPER LOW AN UPPER TROUGH MOVING OVER NEW
ENGLAND AND THE CENTRAL APPALACHIANS AS RIDGING BECOMES MORE
PRONOUNCED FROM THE GULF OF MEXICO NORTHWARD INTO THE PLAINS. THE
NEXT VIGOROUS UPPER LOW WAS DEEPENING OVER THE LAKE WINNIPEG REGION.
ACARS 400-250MB WIND OBSERVATIONS REVEAL A 80-130KT JET NEAR THE
CANADIAN BORDER...TROUGHING OVER THE NORTHERN ROCKIES AND NEW
ENGLAND. 19Z SURFACE ANALYSIS PLACED A 1020MB ANTICYCLONE ACROSS THE
CENTRAL APPALACHIANS. THE PRIMARY BOUNDARY HAS STALLED ACROSS THE
CAROLINAS...AND IS LIFTING ACROSS THE MIDWEST AND TENNESSEE VALLEY
AS A WARM FRONT. THE SECONDARY BOUNDARY HAS STALLED FROM THE CENTRAL
GREAT LAKES SOUTHEAST INTO MARYLAND...THEN NORTHEAST ALONG THE NEW
ENGLAND COAST. A TROUGH WAS NOTED IN THE LEE OF THE APPALACHIANS.
UPDATED THE FORECAST TO REMOVE POPS. NOW PAST DIURNAL HEATING PEAK
SO FEEL ANYTHING THAT WOULD HAVE DEVELOPED IN THE MOUNTAINS WOULD
HAVE DONE SO BY NOW. CUMULUS CONTINUE TO DISSIPATE...BUT WILL KEEP
AN EYE ON THE SHORTWAVE AT THE BASE OF THE UPPER TROUGH NOW PASSING
OVER CENTRAL VIRGINIA. IT MAY ONLY TAKE BRIEF COOLING ATOP THE
BOUNDARY LAYER WITH SUNSET TO INITIATE A SHOWER OR TWO.
NEVERTHELESS...LACK OF CONFIDENCE AND FORECAST COVERAGE HAS LED TO
TAKING THE MENTION OUT OF THE FORECAST AT THIS TIME.
RIDGING BUILDING IN LATER TONIGHT SHOULD KEEP MUCH OF THE CIRRUS
FROM UPSTREAM CONVECTION ACROSS THE MIDWEST FROM REACHING THE AREA
TONIGHT. WITH LOW LEVEL MOISTURE INCREASING AND LIGHT SOUTHERLY
FLOW DECOUPLING...HAVE RETAINED MENTION OF PATCHY FOG ALONG AND
WEST OF THE BLUE RIDGE. LOW TEMPERATURES WILL ALSO BE ABOUT A
CATEGORY HIGHER THAN LAST NIGHT.
&&
.SHORT TERM /6 AM SATURDAY MORNING THROUGH SATURDAY NIGHT/...
MID-LEVEL RIDGE WILL CENTER ITSELF OVER THE MID-ATLANTIC AND RETURN
FLOW AROUND SURFACE HIGH OVER THE WESTERN ATLANTIC WILL ALLOW FOR
WARMER AND MORE HUMID CONDITIONS. MAX TEMPERATURES WILL RANGE FROM
THE MID 80S IN THE POTOMAC HIGHLANDS TO THE LOWER 90S ACROSS MOST
VALLEY LOCATIONS AS WELL AS THE WASHINGTON AND BALTIMORE
METROPOLITAN AREAS. NAM DOES SHOW ISOLATED CONVECTION ACROSS THE
POTOMAC HIGHLANDS AND HIGHER ELEVATIONS OF THE SHENANDOAH VALLEY
SATURDAY AFTERNOON. DESPITE THE LACK OF A TRIGGER...THE LOW-LEVEL
FLOW WILL BE LIGHT ENOUGH FOR TERRAIN CIRCULATION. WILL LEAVE
FORECAST DRY FOR NOW DUE TO THE MID-LEVEL RIDGE PROVIDING A
CAPPING INVERSION.
&&
.LONG TERM /SUNDAY THROUGH FRIDAY/...
INCRG CONVCTV ACTIVITY XPCTD SUN THRU MON AS SFC TROF SHARPENS
ACRS FCST AREA. LOW LVL CNVGNC AND PTLY CLDY SKIES...IN CONCERT
WITH QUALITY MSTR AND APRCHG SHRTWV TROF SHOULD FOSTER TSTM DVLPMT
BY SUN AFTN...MAINLY WEST OF BLUE RIDGE.
INCRG MID LVL STEERING FLOW FROM SW AND LGT SFC WINDS WILL YIELD
SHEAR VECTORS PARALLEL TO SFC BOUNDARY... WHICH COULD SPELL
TRAINING TSTMS. HAVE INCRD QPF FIELDS AND POPS FROM PREV PCKG SUN
AFTN AND EVE...AND THEN ON MON AREAWIDE AS CDFNT MOVES THRU.
SFC HIPRES BUILDS IN LATE MON EVE AND TUE AND WILL AID IN MSTR
EROSION...WITH WARM AND DRY FCST CONTG. FCST AREA WILL BE LOCATED
BENEATH OUTER REACHES OF UPR HIPRES NOSING NWWD FROM ATLNTC...AND
SHOULD YIELD SLY SFC WINDS AND RETURNING MSTR.
&&
.AVIATION /00Z SATURDAY THROUGH WEDNESDAY/...
VFR AND LIGHT WINDS TONIGHT...WITH SOME MVFR/IFR FOG POSSIBLE
MRB/CHO. LIGHT SOUTHERLY WINDS AS HIGH PRESSURE CONTINUES TO EASE
OFF EAST COAST TOMORROW. A VERY REMOTE CHANCE OF A
SHOWER/THUNDERSTORM WEST OF THE BLUE RIDGE TOMORROW AFTERNOON...NOT
WORTHY OF MENTION IN TAFS AT THIS TIME...AS FORECAST VERTICAL
PROFILES INDICATE CAPPING INVERSION REMAINS INTACT.
THREAT OF TSTMS RETURNS SUN AFTN TO MON...WHICH WILL IMPACT MAINLY
WRN TERMINALS SUN AFTN AND EVE...WITH CVRG INCRG AREWIDE LATE SUN
NGT AND MON MRNG.
&&
.MARINE...
SOUTHERLY FLOW INCREASES THIS EVENING INTO TONIGHT...ESPECIALLY
FAVORED CHANNELING LOCATIONS. WINDS FORECAST TO REMAIN BELOW SMALL
CRAFT CRITERIA.
PRES FALLS ACRS THE AREA SUN THRU MON WILL YIELD INCRG SLY WINDS...
WHICH MAY PRODUCE SUSTAINED SPEEDS AND GUSTS THAT EXCEED SMALL
CRAFT ADZY CRITERION. ATTM HAVE KEPT WINDS APRCHG 15KT BUT NO
HIGHER.
TSTMS WILL BE POSSIBLE SUN NGT AND MON...AND MAY NECESSITATE
SPECIAL MARINE WRNGS FOR STG GUSTS.
&&
.LWX WATCHES/WARNINGS/ADVISORIES...
DC...NONE.
MD...NONE.
VA...NONE.
WV...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...LASORSA
NEAR TERM...ROGOWSKI
SHORT TERM...LASORSA
LONG TERM...KRAMAR
AVIATION...ROGOWSKI/KRAMAR
MARINE...ROGOWSKI/KRAMAR
AREA FORECAST DISCUSSION...MESOSCALE UPDATE
NWS DULUTH MN
345 PM CDT FRI JUL 11 2008
.MESOSCALE UPDATE...CONCERNING SEVERE TSTORM POTENTIAL OVER THE
MINNESOTA ARROWHEAD...
THERE IS AN INCREASING THREAT FOR WIND DAMAGE AND QUARTER TO GOLF
BALL SIZE HAIL ACROSS THE MINNESOTA ARROWHEAD AND GUNFLINT TRAIL
REGIONS THROUGH 6 PM.
LATEST OBSERVATIONS BOTH AT THE SURFACE AND FROM PROFILERS/AREA 88D
BASE VELOCITY DISPLAYS AND TAMDAR DATA ALL INDICATE THAT WARM
FRONTAL ZONE FROM THE SFC TO 8000 FT AGL IS TRYING TO SURGE NWD
ACROSS NE MN AND WRN LAKE SUPERIOR AFTER BEING INHIBITED FOR MUCH OF
THE DAY. STORMS THAT HAVE BEEN GOING ON ALL DAY NEAR THE CANADIAN
BORDER HAVE ONCE AGAIN INCREASED IN INTENSITY OVER THE PAST
HOUR..PRESUMABLY IN RESPONSE TO INCREASING FORCING FROM WARM
ADVECTION AND FRONTOGENESIS.
WHILE THE NEAR SURFACE LAYER REMAINS COLD AND STABLE /PER SFC TEMPS
IN THE 50S AND LOWER 60S/..MOST UNSTABLE CAPE ROOTED BETWEEN 850-700
MB UP TO 2000 J/KG AND EFFECTIVE DEEP LAYER SHEAR OF 40 KTS IS MORE
THAN SUFFICIENT TO SUPPORT ELEVATED SUPERCELLS AND QUASI-BOW ECHO
TYPE STRUCTURES. THE TORNADO THREAT IN THE MN ARROWHEAD LOOKS
MINIMAL AT BEST DUE TOT HE STABLE BOUNDARY LAYER. HOWEVER..THE COLD
LAYER NEAR THE SURFACE IS RATHER SHALLOW AND WILL BE GETTING EVEN
MORE SHALLOW WITH TIME..AND THEREFORE SHOULD ALLOW STRONG DOWNDRAFTS
TO PENETRATE TO THE SURFACE..ALONG WITH LARGE HAIL.
MILLER
&&
.DLH WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
LS...SMALL CRAFT ADVISORY UNTIL 3 PM CDT THIS AFTERNOON FOR LSZ142-
LSZ143-LSZ144-LSZ145.
$$
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
245 PM CDT FRI JUL 11 2008
.DISCUSSION...
STRONG UPPER LEVEL TROUGH ALONG WITH A POTENT COLD FRONT...WILL PUSH
ACROSS MUCH OF THE UPPER MIDWEST THIS EVENING AND OVERNIGHT. TSRA
EXPECTED TO FIRE ALONG THE COLD FRONT AND TREK EAST OVER INTO
WESTERN WISCONSIN TONIGHT. SFC TEMPS HAVE SOARED INTO THE UPPER 80S
AND LOWER 90S AHEAD OF THE FRONT OVER WEST CENTRAL MN. LAPSWRF MODEL
HAS TSRA DEVELOPING AND BECOMES MORE WIDESPREAD BETWEEN 23Z-02Z OVER
EAST CENTRAL MN. THE INTIAL SEVERE WEATHER THREAT WILL BE DAMAGING
WINDS AND TORRENTIAL RAINS. A FEW DECRETE SUPERCELLS COULD PRODUCE
TORNADOES. EXPECT MORE OF A LINEAR LINE OF TSRA OCCURRING LATER THIS
EVENING/OVERNIGHT. PRECIP WATER VALUES INCREASE TO OVER 2.00
INCHES. WET BULB ZERO ARE OVER 12000 FEET. CAP STRENGTH(INHIBITION
FOR DEVELOPMENT OF TSRA) REMAINS FAIRLY STRONG ACROSS MUCH OF THE
FORECAST AREA AT THIS TIME. AIRMASS SHOULD RAPIDLY DESTABLIZED IN
THE VICINITY AND JUST AHEAD OF THE COLD FRONT.
PRECIP MOVING OUT OF CWA OVERNIGHT...THEN A DRY WEATHER PATTERN OVER
THE NEXT FEW DAYS. DRY NORTHWEST AIR FLOW PREVAILING OVER THE UPPER
MIDWEST THROUGH MONDAY.
MEDIUM AND LONG RANGE MODELS...ALL INDICATE A RATHER UNSETTLED
WEATHER PATTERN OVER THE UPPER MIDWEST WITH SEVERAL WEAK SHORT WAVE
TROUGH MOVING THROUGH THE WESTERLY FLOW.
&&
.AVIATION.../18Z TAF ISSUANCE/
A LOT GOING ON WITH AVIATION-PERTAINING WEATHER THROUGH THE
EVENING...WITH THE PRIMARY CONCERN BEING STRONG THUNDERSTORM
WINDS. FIRST...MVFR CIGS HAVE DEVELOPED IN FAR ERN MN AND WRN WI
FROM STABLE CLOUDS LEFT IN THE WAKE OF EARLY MORNING CONVECTION.
THESE SHOULD BEGIN TO LIFT DUE TO MIXING AND INDICATIONS ON TAMDAR
SOUNDINGS THAT THE LAYER IS BECOMING SOMEWHAT THIN. THE AIRCRAFT
SOUNDINGS ALSO INDICATE TWO SEPARATE INVERSIONS...WITH THE HIGHER
ONE CAPPING THE ATMOSPHERE FROM CONVECTION UNTIL LATE AFTN AT THE
EARLIEST OVER MSP AND WI TAF SITES. MORE LIKELY IT WILL BE EARLY
EVE FOR THESE.
CONVECTION EXPECTED TO DEVELOP NEAR THE DAKOTAS AND WRN MN BORDER
AHEAD OF STRONG COLD FRONT. SOME OF THIS WILL LIKELY BE SEVERE
NEAR INITIATION AND ESPECIALLY WITHIN THE HOURS THAT FOLLOW.
STORMS WILL INITIALLY BE SCATTERED BEFORE LIKELY CONGEALING INTO
SOMEWHAT OF A BROKEN LINE BY THE TIME THEY REACH MSP. SO AXN AND
RWF DO HAVE A REASONABLE CHANCE TO NOT GET HIT DIRECTLY...BUT
STILL HAVE INCLUDED A STRONGLY WORDED TEMPO GIVEN THE ENVIRONMENT
FOR WINDS. LARGE HAIL ALSO A POSSIBILITY AT THESE TAF SITES.
FURTHER EAST AS THE STORMS ORGANIZE...WINDS SHOULD BE THE PRIMARY
THREAT. THERE MAY BE SOME ISOLD TO SCT STORM DEVELOPMENT OUT AHEAD
OF THIS LINE...SO HAVE A VCTS AT MSP AND WI TAF SITES. BUT MAIN
SHOW SHOULD BE WHEN LINE COMES THROUGH. IFR CONDITIONS AND STRONG
WINDS ARE LIKELY WITH THESE THUNDERSTORMS. FORECAST CONDITIONS IN
THE MSP TAF ARE FOR AN AIRPORT WEATHER WARNING...SO ISSUANCE IS
CURRENTLY EXPECTED AS THE 00Z TO 03Z TIME PERIOD APPROACHES...AS
LONG AS STORMS BEHAVE AS EXPECTED. THE FRONT WILL MOVE THROUGH WRN
WI BETWEEN 02Z AND 05Z WITH THE STORMS LIKELY MAINTAINING THEIR
STRENGTH.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
&&
$$
AREA FORECAST DISCUSSION...UPDATED
NWS TWIN CITIES/CHANHASSEN MN
122 PM CDT FRI JUL 11 2008
.UPDATE...
.DISCUSSION...
A WATCH IS ANTICIPATED TO COME OUT SOON FOR WRN MN. GOES VISIBLE
CHANNEL SHOWING CU DEVELOPMENT ALONG FRONT...WHICH EXTENDS FROM
995 MB LOW NEAR GFK TO JUST EAST OF I-29 IN SD. LIKELY MORE RAPID
DEVELOPMENT IN ERN ND/NW MN BEFORE ERN SD WITH THE STRENGTH OF
CAP FURTHER SOUTH. HOWEVER...BETWEEN 3 AND 430 PM...DO THINK
ISOLD TO SCT T-STORMS WILL DEVELOP RAPIDLY NEAR WRN MN BORDER.
EXPLOSIVE CAPE POTENTIAL SHOWN ON 12Z ABR SOUNDING / 5400 J/KG /
AND ALL MODELS INDICATE THOSE VALUES ADVECTED INTO WRN MN. BEST
SHEAR VALUES...BOTH DEEP LAYER AND LOW LEVELS...ARE CERTAINLY OVER
NRN MN. HOWEVER...THERE IS SUFFICIENT 0-6KM AND 0-8KM SHEAR FOR
SUPERCELLULAR STORMS...ESPECIALLY GIVEN THE WIDE NATURE OF THE
CAPE WITH THE FORECAST VERTICAL PARCEL TRAJECTORIES. THIS CAN
EASILY OVERCOME THE SOMEWHAT MARGINAL SHEAR VALUES. STORMS SHOULD
SLOWLY MERGE...FEEDING ON THE INSTABILITY AHEAD OF THEM IN CTRL
AND ERN MN AS MLCIN WEAKENS RAPIDLY. MAY BE SOME POTENTIAL ROGUE
DEVELOPMENT OUT AHEAD OF THE MAIN LINE IN ERN MN AND WRN WI AS
LLJ BEGINS TO INTENSIFY. BUT MAIN SHOW SHOULD BE THIS BROKEN TO
SOLID LINE OF THUNDERSTORMS AS IT COMES THROUGH ERN TWO-THIRDS OF
THE FORECAST AREA. THIS INCLUDES THE TWIN CITIES...WITH OUR BEST
ESTIMATE BEING BETWEEN 6:30 PM AND 9:30 PM. WIND POTENTIAL IS
GREAT...GIVEN LARGE DELTA THETA-E VALUES IN THE VERTICAL ON
FORECAST SOUNDINGS...ALONG WITH UNIDIRECTIONAL WRLY WINDS TAKING
SHAPE BEHIND THE BOUNDARY. THIS INCLUDES 50 KTS AT 700 MB...FAIRLY
STRONG FOR THE MIDDLE OF THE WARM SEASON. GIVEN HIGHER
ENVIRONMENTAL MOISTURE...ALL STORMS SHOULD HAVE THE ABILITY TO PUT
DOWN A QUICK BURST OF HEAVY RAINFALL. STORM RELATIVE WINDS ARE
SOMEWHAT FAVORABLE FOR QLCS ROTATIONS ALONG THIS LINE OF
STORMS...ESPECIALLY AS IT INTERSECTS INTENSIFYING LLJ IN ERN MN
AND WRN WI THIS EVE.
&&
.PREV DISCUSSION...
CONVECTION SLIDING SOUTHEAST ACROSS THE TWIN CITIES AND ADJOINING
AREAS OF WEST CENTRAL WI ATTM. ACTIVITY IS ALONG A MEANDERING WARM
FRONT FROM KEAU-KMSP-KABR. THE WARM FRONT WILL BE LIFTING
NORTHWARD THIS MORNING AS A STRONG UPPER TROF AND SURFACE COLD
FRONT ADVANCE ACROSS THE DAKOTAS. KEPT SOME POPS IN FOR EASTERN
AREAS OF THE CWA THIS MORNING...WITH MID LEVEL CAP FORMING OVER
THE WESTERN CWA. CURRENT RUC ANAL SHOWING +12 DEG C AT 700MB INTO
WEST CENTRAL MN WITH +14 SPREADING IN BY MID DAY.
THE COLD FRONT OVER THE DAKOTAS WILL PUSH INTO THE WESTERN CWA
AROUND 21Z...REACH THE TWIN CITIES AROUND 03Z AND KEAU BY 08Z.
MAINTAINED LIKELY POPS OVER CENTRAL MN IN THE 21Z-24Z TIME FRAME
AND OVER EASTERN MN AND WEST CENTRAL WI FROM 00Z-06Z. SEVERE
STORMS ARE LIKELY WITH LARGE HAIL AND DAMAGING WINDS. TORNADO
PROBABILITY EQUATIONS SHOWING SOME POTENTIAL OVER NE MN ALONG THE
INTERSECTION OF THE WARM AND COLD FRONT. ANOTHER CONCERN EARLY
TONIGHT WILL BE TORRENTIAL RAINS. EARLY THIS MORNING THERE WERE
LOCATIONS ACROSS CENTRAL MN THAT RECEIVED NEARLY AN INCH IN AN
HOUR WITH PW`S JUST OVER AN INCH. THE PW IS FORECAST TO INCREASE
TO AROUND 2 INCHES OVER THE EASTERN TWO-THIRDS OF THE CWA DURING
THE LATE AFTERNOON AND EVENING. HAVE INCLUDED SEVERE WORDING AND
HEAVY RAIN IN THE ZFP/SAF.
KEPT HIGHS IN THE LOWER TO MIDDLE 90S THIS AFTERNOON OVER MUCH OF
THE MN CWA. BEST AREAS TO ACHIEVE MIDDLE 90S WOULD BE OVER
SOUTHWEST MN WHERE LITTLE RAIN HAS FALLEN IN THE PAST DAY.
THINGS BEGIN TO QUIET DOWN LATE TONIGHT IN THE WAKE OF THE FRONT.
STILL BREEZY ON SATURDAY AS A DEEP SURFACE LOW MAKES ITS WAY
ACROSS ONTARIO. A RIDGE OF HIGH PRESSURE WILL THEN OVERSPREAD THE
CWA SUNDAY AND MONDAY WITH SEASONAL TEMPERATURES AND DRY WEATHER.
NOT MUCH TIME TO LOOK AT LATER PERIODS...BUT THUNDERSTORMS SHOULD BE
RETURNING TO THE WESTERN CWA ON TUESDAY AND ACROSS THE REST OF THE
FA TUESDAY NIGHT. THE THREAT FOR STORMS WILL LINGER IN THE MIDDLE
OF THE WEEK AS A FRONTAL BOUNDARY BECOMES STATIONARY ACROSS THE
FA. 00Z ECMWF PAINTING A PRETTY WET/STORMY PERIOD.
&&
.AVIATION.../18Z TAF ISSUANCE/
A LOT GOING ON WITH AVIATION-PERTAINING WEATHER THROUGH THE
EVENING...WITH THE PRIMARY CONCERN BEING STRONG THUNDERSTORM
WINDS. FIRST...MVFR CIGS HAVE DEVELOPED IN FAR ERN MN AND WRN WI
FROM STABLE CLOUDS LEFT IN THE WAKE OF EARLY MORNING CONVECTION.
THESE SHOULD BEGIN TO LIFT DUE TO MIXING AND INDICATIONS ON TAMDAR
SOUNDINGS THAT THE LAYER IS BECOMING SOMEWHAT THIN. THE AIRCRAFT
SOUNDINGS ALSO INDICATE TWO SEPARATE INVERSIONS...WITH THE HIGHER
ONE CAPPING THE ATMOSPHERE FROM CONVECTION UNTIL LATE AFTN AT THE
EARLIEST OVER MSP AND WI TAF SITES. MORE LIKELY IT WILL BE EARLY
EVE FOR THESE.
CONVECTION EXPECTED TO DEVELOP NEAR THE DAKOTAS AND WRN MN BORDER
AHEAD OF STRONG COLD FRONT. SOME OF THIS WILL LIKELY BE SEVERE
NEAR INITIATION AND ESPECIALLY WITHIN THE HOURS THAT FOLLOW.
STORMS WILL INITIALLY BE SCATTERED BEFORE LIKELY CONGEALING INTO
SOMEWHAT OF A BROKEN LINE BY THE TIME THEY REACH MSP. SO AXN AND
RWF DO HAVE A REASONABLE CHANCE TO NOT GET HIT DIRECTLY...BUT
STILL HAVE INCLUDED A STRONGLY WORDED TEMPO GIVEN THE ENVIRONMENT
FOR WINDS. LARGE HAIL ALSO A POSSIBILITY AT THESE TAF SITES.
FURTHER EAST AS THE STORMS ORGANIZE...WINDS SHOULD BE THE PRIMARY
THREAT. THERE MAY BE SOME ISOLD TO SCT STORM DEVELOPMENT OUT AHEAD
OF THIS LINE...SO HAVE A VCTS AT MSP AND WI TAF SITES. BUT MAIN
SHOW SHOULD BE WHEN LINE COMES THROUGH. IFR CONDITIONS AND STRONG
WINDS ARE LIKELY WITH THESE THUNDERSTORMS. FORECAST CONDITIONS IN
THE MSP TAF ARE FOR AN AIRPORT WEATHER WARNING...SO ISSUANCE IS
CURRENTLY EXPECTED AS THE 00Z TO 03Z TIME PERIOD APPROACHES...AS
LONG AS STORMS BEHAVE AS EXPECTED. THE FRONT WILL MOVE THROUGH WRN
WI BETWEEN 02Z AND 05Z WITH THE STORMS LIKELY MAINTAINING THEIR
STRENGTH.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
&&
$$
RAH/MTF
AREA FORECAST DISCUSSION
NWS NORTH PLATTE NE
253 PM CDT FRI JUL 11 2008
.SYNOPSIS...
COLD FRONT CUTS CWA IN HALF FROM KONL TO KOGA EARLY THIS
AFTERNOON. ACCAS TO THE SOUTH OF THE FRONT WITH TD`S IN THE 40S
NORTH AND THE 60S AND 70S SOUTH AND EAST.
&&
.DISCUSSION...
MODELS IN FAIR AGREEMENT TODAY AND HAVE USED A BLEND FOR THE
FORECAST. SOME ECHOES STARTING TO DEVELOP OVER SOUTH CENTRAL
NEBRASKA AS SEEN ON KLNX. SOUTHERN AND NORTH CENTRAL ZONES STILL
UNDER THE GUN. SECONDARY WAVE MOVING THROUGH THE UPPER PATTERN
LATE TONIGHT AND WILL SEND SOME MID LEVEL CLOUDS THROUGH BUT WITH
DRIER LOWER LEVELS VIRGA AT BEST. TEMPERATURES WILL COOL
SIGNIFICANTLY TONIGHT IN WAKE OF FRONTAL PASSAGE AND CLEARING
SKIES. HAVE GENERALLY FOLLOWED COOLER 2 METER TEMPS. MID 40S
NORTHWEST AND 50S SOUTH. TEMPERATURES SOME 10 TO 15 DEGREES COOLER
ON SATURDAY ONLY IN THE 80S. TEMPERATURES WILL AGAIN FALL OFF ON
SATURDAY NIGHT. SUNDAY FULL SUN AND RISING H5 HEIGHTS TEMPERATURES
NORMAL FOR THE SEASON.
EXTENDED MONDAY THROUGH FRIDAY...SERIES OF WEAK WAVES MOVING
THROUGH RIDGE AND WILL HAVE THE OPPORTUNITY FOR ISOLATED
CONVECTION NEARLY EVERY DAY. HAVE FOCUSED ON FRONTAL PASSAGE TUESDAY
INTO WEDNESDAY WITH SCHC POPS RETAINED. BOTH GFS AND ECMWF
STALLING OUT THE FRONT FROM WEDNESDAY ONWARD. WILL WAIT FOR
FURTHER RUNS TO PINPOINT BETTER.
&&
.AVIATION...
A COLD FRONT MOVING THROUGH THE REMAINDER OF SOUTHWEST AND CENTRAL
NEBRASKA WILL BE THE FOCUS FOR STRONG TO SEVERE THUNDERSTORMS THIS
EVENING. VFR CONDITIONS SHOULD PRIMARILY BE EXPECTED...WITH SOME
REDUCTION TO MVFR POSSIBLE NEAR THE STRONGEST STORMS WITH BOTH VSBY
AND CIGS FALLING TO THIS CRITERIA. WINDS NEAR THESE STORMS AND THE
POSSIBILITY OF HAIL WILL BE DEFINITE HAZARDS TO LIGHT AIRCRAFT. A
FEW WINDS GUSTS...NOT RELATED TO THUNDERSTORMS...UP TO 35 MPH FROM
THE NORTH WILL BE POSSIBLE BEHIND THIS FRONT.
&&
.FIRE WEATHER...
COOL...DRY HIGH PRESSURE WILL DROP INTO NEBRASKA BEHIND THE FRONT
MOVING THROUGH THE STATE THIS EVENING. DEEP WESTERLY FLOW WILL ALLOW
THESE DRY CONDTIONS TO MIX TO THE SURFACE AND KEEP RELATIVE HUMIDITY
LEVELS DOWN TO AROUND 20 PERCENT BY SATURDAY AFTERNOON. AT THE
MOMENT WINDS LOOK TO REMAIN AT OR BELOW 20 MPH THROUGH THE AFTERNOON
HOURS.
&&
.LBF WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
13/POWER
AREA FORECAST DISCUSSION
NWS MEMPHIS TN
1147 AM CDT FRI JUL 11 2008
.UPDATE...
NO CHANGES PLANNED THIS MORNING AS THE FORECAST LOOKS TO BE IN
GOOD SHAPE. A CU FIELD IS STARTING TO DEVELOP OVER NORTH
MISSISSIPPI SO EXPECTING CONVECTION TO DEVELOP SHORTLY WITH THE
BEST CHANCES ACROSS WEST TENNESSEE AND NORTH MISSISSIPPI. HIGH
TEMPERATURES SHOULD HIT WELL INTO THE LOW TO MID 90S.
&&
.PREV DISCUSSION... /ISSUED 426 AM CDT FRI JUL 11 2008/
DISCUSSION...
RAIN CHANCES AND ISOLATED STRONG TO SEVERE STORM POTENTIAL THROUGH
SUNDAY ARE THE MAIN CONCERNS. ANOTHER CONCERN IS HOT TEMPERATURES
ON SATURDAY.
LATEST MODELS WERE IN FAIR TO GOOD AGREEMENT. THINK THE LATEST
GFS MODEL RUN...00Z FRI...HANDLES THINGS BEST AS IT SEEMS TO BE
HANDLING MOISTURE FIELDS BEST THROUGH SUNDAY...SO LEANED TOWARDS
ITS SOLUTION.
NO SIGNIFICANT CHANGES WERE MADE TO THE PREVIOUS FORECAST.
AT 415 AM CDT...MUGGY CONDITIONS PREVAILED OVER THE MIDSOUTH
AND FORECAST AREA WITH TEMPERATURES MAINLY IN THE LOWER 70S.
PATCHY FOG WAS OVER THE AREA AS SKIES HAVE CLEARED. THE NEAREST
RAIN WAS NEAR THE MO/AR BORDER.
THIS MORNING...PATCHY FOG WILL QUICKLY LIFT BY 9 AM CDT...GIVING
WAY TO MOSTLY OR PARTLY SUNNY SKIES. THINK MOST AREAS WILL REMAIN
DRY...EXCEPT PERHAPS OVER FAR NE AR AND MO BOOTHEEL WHERE A FEW
SHOWERS MAY BE AROUND.
THIS AFTERNOON...RAIN CHANCES AND TEMPERATURES ARE THE BIG
CHALLENGES...BUT OVERALL...THINK RAIN COVERAGE WILL BE LESS AND
TEMPERATURES WILL BE WARMER TODAY. LATEST MDCRS SOUNDINGS INDICATE
CONSIDERABLE WARMING BELOW 750 MB...WHICH SHOULD HELP CAP THE AIR
MORE TODAY AND LIMIT RAIN CHANCES SOME...ESPECIALLY WEST OF THE
MS RIVER. THINK THE HIGHEST RAIN CHANCES WILL BE ROUGHLY EAST OF
INTERSTATE 55 AND SOUTH OF INTERSTATE 40 WHERE CAPPING WILL BE
WEAKEST WITH COOLEST LOW LEVEL TEMPERATURES. TEMPERATURES WILL BE
WARMER IN MOST LOCATIONS...RANGING FROM THE UPPER 80S NEAR THE TN
RIVER UNDER MORE CLOUDS AND RAIN TO THE MID 90S WEST OF THE MS
RIVER WHERE MORE SUN WILL OCCUR.
A FEW STORMS MAY BE ON THE STRONG TO SEVERE SIDE THIS AFTERNOON
AND EARLY EVENING AS THE AIR WILL BE MOIST AND UNSTABLE...
PRECIPITABLE WATER VALUES AROUND 2 INCHES AND LIFTED INDICES -4 TO
-6 WITH SBCAPES 2500-3000 J/KG. WITH VERY WEAK MID LEVEL WINDS...
STORMS WILL BE PULSE TYPE AND UNORGANIZED IN NATURE.
HEAVY RAINFALL AND LOCALIZED FLOODING ARE POSSIBLE FROM
ANY STORM. ADDED THESE HAZARDS TO THE LATEST HWO.
TONIGHT...CONVECTION SHOULD DIMINISH QUICKLY THIS EVENING...GIVING
WAY TO A WARM MUGGY NIGHT UNDER MOSTLY CLEAR OR PARTLY CLOUDY SKIES.
LOWS WILL BE IN THE 70S.
SATURDAY IS EXPECTED TO BE WARMER AND DRIER THAN TODAY.
WITH HIGHS GETTING INTO THE 90S EVERYWHERE AND DEWPOINTS AROUND
70...AFTERNOON HEAT INDICES WILL EXCEED 100 DEGREES IN MANY
LOCATIONS...AND MAY BE CLOSE TO 105 DEGREES. RIGHT NOW...NOT
PLANNING ON ANY ADVISORY HEADLINES AS THE DURATION OF HEAT WILL
ONLY BE ONE DAY. CAUTION IS ADVISED TO PERSONS ENGAGING IN
OUTDOOR ACTIVITIES. KEPT LOW RAIN CHANCES MOST PLACES FOR SOME
AFTERNOON STORM DEVELOPMENT WITH HIGHEST CHANCES EAST OF THE
MS RIVER. ANY STORM COULD BE ON THE STRONG SIDE.
SATURDAY NIGHT INTO SUNDAY...RAIN CHANCES WILL DEFINITELY INCREASE
AS A COLD FRONT MOVES THROUGH THE AREA. THINK MOST AREAS WILL GET
WET...SO KEPT RATHER HIGH RAIN CHANCES DURING THIS TIME FRAME.
SOME STORMS MAY BE STRONG TO SEVERE WITH DAMAGING WINDS AND HEAVY
RAINFALL...THOUGH WIDESPREAD SEVERE POTENTIAL REMAINS LOW.
SUNDAY NIGHT THROUGH TUESDAY...COOLER AND MUCH DRIER AIR WILL MOVE
INTO THE AREA BEHIND THE IMPRESSIVE COLD FRONT. SURFACE DEWPOINTS
WILL PROBABLY FALL INTO THE 50S ON MONDAY. LOWS SUNDAY AND MONDAY
NIGHT WILL BE RATHER COOL FOR THIS TIME OF YEAR...RANGING FROM THE
LOWER 60S IN COLDEST RURAL LOCATIONS TO 70 IN URBAN AREAS.
HIGHS MONDAY AND TUESDAY WILL BE IN THE UPPER 80S AND LOWER 90S.
WEDNESDAY AND THURSDAY...DRY WEATHER IS EXPECTED WITH TEMPERATURES
REBOUNDING TO ABOVE NORMAL VALUES. HIGHS WILL BE IN 90S AND LOWS
IN THE LOWER 70S. TROPICAL MOISTURE MAY RETURN BY THE END OF THE
WEEK...BUT FORECAST CONFIDENCE REMAINS LOW.
&&
.PRELIMINARY POINT TEMPS/POPS...
MEM 93 76 96 75 / 20 20 20 40
MKL 91 73 93 71 / 40 20 30 50
JBR 96 75 97 72 / 20 20 20 60
TUP 91 73 94 73 / 50 20 30 20
&&
.MEG WATCHES/WARNINGS/ADVISORIES...
AR...NONE.
MO...NONE.
MS...NONE.
TN...NONE.
&&
$$
KNS/MBS
AREA FORECAST DISCUSSION
NWS SEATTLE WA
935 PM PDT WED JUL 9 2008
.SYNOPSIS...A LOW PRESSURE SYSTEM MOVING ACROSS WESTERN CANADA WILL
RESULT IN SOME COOLING ON THURSDAY. WARMER WEATHER WILL RETURN ON
FRIDAY AND PERSIST THROUGH SATURDAY UNDER HIGH PRESSURE ALOFT. THIS
COMBINED WITH WEAKER ONSHORE FLOW WILL RESULT IN ABOVE NORMAL
DAYTIME TEMPERATURES... ESPECIALLY ON SATURDAY. ONSHORE FLOW WILL
STRENGTHEN ON SUNDAY FOR SOME COOLING.
&&
.SHORT TERM...QUESTION FOR TONIGHT IS HOW MUCH STRATUS WILL MAKE IT
INTO THE INTERIOR THURSDAY MORNING. MODEL GUIDANCE ALL OVER THE
PLACE WITH THE NAM BRINGING THE STRATUS IN BRIEFLY WHILE THE GFS HAS
NOTHING AT ALL. 12Z WRF-MM5 HAD STRATUS OVER THE INTERIOR IN THE
MORNING BUT THE NEW 00Z RUN HAS DIMINISHED THE COVERAGE
SIGNIFICANTLY. BELIEVE THIS TREND IS THE WAY TO GO. REASON
WHY...CURRENT SATELLITE IMAGERY SHOWS LESS STRATUS ALONG THE COAST
AND IN THE STRAIT THAN THE PREVIOUS TWO NIGHTS. SURFACE GRADIENTS
ARE TRENDING ONSHORE WITH KOTH-KSEA NOW POSITIVE BUT KHQM-KSEA
GRADIENT STILL ONLY 1.3 MB AND BARELY RISING AT 04Z. THIS DOES NOT
BODE WELL FOR WIDESPREAD STRATUS OVER THE INTERIOR IN THE MORNING.
ACARS SOUNDINGS OUT OF KSEA AND KBFI INDICATE WINDS FROM THE SURFACE
TO 850 MB CONTINUE TO BE LIGHT NORTHWESTERLY WITH WEST NORTHWESTERLY
WINDS IN THE 850-700 MB. MODEL CROSS SECTIONS FOR THURSDAY MORNING
NEVER DO TURN THE LOW LEVEL WINDS AROUND TO SW EXCEPT FOR RIGHT AT
THE SURFACE IN THE MORNING. FOR THE POSSIBILITY OF THE STRATUS
FORMING IN PLACE DURING THE MORNING HOURS CURRENT DEW POINTS ARE
MOSTLY IN THE MID 40S AND RUNNING 5 TO 10 DEGREES LOWER VERSUS LAST
NIGHT. BECAUSE OF THESE VARIABLES WILL GO AHEAD AND UPDATE THE ZONES
AND REDUCE THE COVERAGE OF THE MORNING CLOUDS FOR THE INTERIOR
SECTIONS THURSDAY MORNING. BEYOND THURSDAY MORNING CURRENT
FORECAST IN GOOD SHAPE WITH THE UPPER LEVEL RIDGE REBUILDING OVER
WESTERN WASHINGTON THURSDAY NIGHT AND FRIDAY. BY 00Z SAT 500 MB
HEIGHTS BACK UP TO 582-586 DM OVER THE REGION WITH NORTHWESTERLY
SURFACE GRADIENTS. A SIMILAR SCENARIO TO WHAT WE JUST HAD THE LAST
COUPLE OF DAYS. UPPER LEVEL RIDGE REMAINING INTACT ON SATURDAY FOR
ANOTHER SUNNY DAY WITH HIGHS A FEW DEGREES ABOVE NORMAL. FELTON
.LONG TERM...PREVIOUS DISCUSSION FOLLOWS...
CONFIDENCE IN THIS PERIOD WAS NOT HIGH. TIMING OF THE NEXT TROF
APPEARED TO BE THE MAIN PROBLEM. THE 12Z ECMWF DELAYED THIS TROF TIL
MON...AND THE 12Z GFS WAS SLOWER THAN ITS PREVIOUS RUN. THEREFORE
HAVE FOLLOWED SUIT. CONSEQUENTLY...EXPECT DAYTIME TEMPS ON SUNDAY TO
BE SLIGHTLY ABOVE NORMAL...AND BELOW NORMAL ON MON DUE TO INCREASED
ONSHORE FLOW AND A DEEPER MARINE LAYER. HAVE BROADBRUSHED THE
FORECAST BEYOND MON TO INDICATE NEAR OR SLIGHTLY BELOW NORMAL TEMPS
ALONG WITH NIGHT/MORNING CLOUDS.
&&
.AVIATION...LIGHT WESTERLY FLOW ALOFT OVER AREA TODAY WILL BECOME
NWLY THURSDAY AS AN UPPER LEVEL TROUGH DIGS INTO NORTHERN IDAHO.
WEAK ONSHORE GRADIENTS OVERNIGHT SUPPORT THE IDEA OF A WEAK PUSH BY
THURSDAY MORNING. GFS MOS IS A BIT MORE RESTRAINED...BRINGING THE
MARINE LAYER INTO NORTHERN INTERIOR AREAS BUT KEEPING THE SOUTHWEST
INTERIOR MOSTLY CLEAR. IT SEEMS THE GFS RESTRAINT MAY BE IN ORDER AS
NOT MUCH STRATUS HAS FORMED ON THE COAST THIS EVENING. WILL BACK OFF
ON THE IDEA OF MARINE LAYER MAKING IT INTO MOST INLAND AREAS BY
MORNING. IFR CONDITIONS POSSIBLE IN AREAS AFFECTED BY THE MARINE
LAYER...BUT THESE AREAS SHOULD BE RELATIVELY SMALL...THE COAST AND
MAYBE STRAIT. AREAS OF LOW CLOUDS WILL BURN OFF BY LATE MORNING OR
EARLY AFTERNOON GIVING WAY TO VFR CONDITIONS OVER THE AREA.
KSEA...VFR CONDITIONS OVERNIGHT. MORNING STRATUS UNLIKELY BUT
POSSIBLE FOR A FEW HOURS 13-17Z.
&&
.MARINE...STRONG OFFSHORE SURFACE HIGH GRADUALLY SHIFTING EAST WILL
HELP INCREASE ONSHORE FLOW THROUGH THE STRAIT OVERNIGHT. ONSHORE
GRADIENTS AND FLOW WILL PEAK AROUND MIDNIGHT WITH WESTERLY GALES
EXPECTED THROUGH THE CENTRAL AND EASTERN STRAIT OF JUAN DE FUCA.
MODERATE LOW LEVEL ONSHORE FLOW WILL PERSIST ACROSS W WA OVER THE
NEXT SEVERAL DAYS.
&&
.SEW WATCHES/WARNINGS/ADVISORIES...
GALE WARNING CENTRAL AND EAST STRAIT OF JUAN DE FUCA.
SMALL CRAFT ADVISORY COASTAL WATERS...WEST STRAIT OF JUAN DE
FUCA...ADMIRALTY INLET AND NORTHERN INLAND WATERS.
$$
WEATHER.GOV/SEATTLE
AREA FORECAST DISCUSSION
NWS GREEN BAY WI
350 PM CDT FRI JUL 11 2008
.SHORT TERM...TONIGHT AND SATURDAY...MAIN FCST CONCERNS ARE PCPN
TRENDS AND POTENTIAL FOR SVR TSTMS TONIGHT...THEN TEMPS AND
ARRIVAL OF MUCH DRIER AIR ON SATURDAY.
MAIN WARM FRONT WAS STILL SITUATED SW OF GRB CWA THIS AFTERNOON...
BUT APPEARED TO BE REORGANIZING OVER N IL. THIS BOUNDARY SHOULD
SHIFT STEADILY NORTH INTO GRB CWA THIS EVG...AS SOUTHERLY FLOW
INCREASES IN ADVANCE OF THE APPROACHING NORTHERN PLAINS COLD
FRONT. CAPPING INVERSION IS VERY STG OVER EASTERN MN...WHERE
TAMDAR SOUNDINGS SHOW 700 MB TEMPS AROUND +12 TO +13 C...BUT
IS WEAKER OVER GRB CWA...WHERE 19Z TAMDARS SHOW +9 TO +10 C.
WITH THE LLJ INCREASING THIS EVG...THE WARM FRONT LIFTING
THROUGH...AND OUR AREA SITUATED ON THE EASTERN PERIPHERY OF THE
CAP...THINK THAT SCT TSTMS WILL REDEVELOP THIS EVG. ISOLD SVR
STORMS ARE PSBL...WITH DAMAGING WINDS THE PRIMARY THREAT.
LATER TONIGHT...MODELS SHOW CONVECTION ASSOC WITH THE
APPROACHING COLD FRONT REACHING OUR NW COUNTIES TOWARD
MIDNIGHT...THEN SHIFTING EAST AND GRADUALLY WEAKENING OVERNIGHT.
THIS SEEMS REASONABLE...GIVEN THE UNFAVORABLE TIMING OF THE
FROPA...AND THE MAIN UPPER LEVEL FORCING STAYING TO OUR NW.
WILL MAINTAIN LIKELY POPS FOR THE ENTIRE CWA...WITH HIGHEST
POPS IN OUR NW COUNTIES. SVR THREAT SHOULD BE CONFINED TO
NC/C WI DURING THE VERY LATE EVG AND EARLY MORNING HOURS.
ON SATURDAY...CONTINUED THE PREVIOUS FCST OF LINGERING POPS
IN OUR SE COUNTIES DURING THE MORNING...THEN DRY FOR THE
AFTERNOON. MUCH DRIER AIR WILL ADVECT INTO THE CWA ON GUSTY
WEST WINDS. AVG MIXING RATIOS IN THE BOUNDARY SUPPORT DEW
POINTS FAILLING INTO THE MID 40S ACROSS NC WI DURING THE
AFTERNOON. DEEP MIXING THROUGH 800-750 MB YIELDS MAX TEMPS
IN THE UPPER 70S TO MIDDLE 80S.
.LONG TERM...SAT NGT THRU NXT FRI. MAIN STORM TRACK TO CONT
RUNNING ALONG THE NRN TIER OF STATES NXT WEEK AS A SPRAWLING
SUBTROPICAL UPR RDG SETS UP SHOP OVR THE SRN CONUS. AN UPR TROF IS
EXPECTED TO DROP SWD TOWARD BRITISH COLUMBIA WHICH MAY LIFT THE
MAIN STORM TRACK FARTHER NORTH BY LATE WEEK. AFTER A QUIET START
TO THE WORK WEEK...PCPN CHCS WL BECOME A CONCERN OVR NE WI AS A
FNTL BNDRY HANGS AROUND THE RGN.
WEDGE OF DRY AIR/SUBSIDENCE WL PREVENT ANY PCPN FROM AFFECTING NE
WI SAT NGT. THERE WL BE SOME INCREASE IN CLDS OVR NRN WI LTR SAT
NGT AS WRAP-AROUND MSTR FROM THE ONTARIO UPR LOW ROTATES THRU THAT
PART OF THE STATE. AS A RESULT...HAVE RAISED MIN TEMPS A COUPLE OF
DEGS OVR NRN AND PARTS OF CNTRL WI.
WRAP-AROUND MSTR PEELS AWAY FROM NRN WI SUNDAY MORNING LEAVING THE
RGN BETWEEN THE DEPARTED SFC LOW WELL TO OUR NE (JAMES BAY) AND
WEAK HI PRES OVR THE CNTRL CONUS. THERE WAS A CONCERN THAT THE WRN
GREAT LKS COULD DESTABILIZE ENUF TO ALLOW A WEAK SHRTWV TO KICK
OFF A SHWR OR TWO. AT THIS POINT...THAT SHRTWV IS PROGGED BY THE
MDLS TO REMAIN VERY WEAK AND WITH NO OTHER FOCUSING MECHANISMS
PRESENT OR MUCH MSTR AVBL (DEW PTS IN THE 40S/50S)...PREFER TO GO
DRY FOR THE ENTIRE FCST AREA ON SUNDAY. EXPECT BREEZY CONDITIONS
WITH SUSTAINED WNDS OF 15 TO 20 MPH ACCOMPANIED BY HIGHER GUSTS.
THAT WEAK SFC HI IS EXPECTED TO RDG INTO THE WRN GREAT LKS SUNDAY
NGT AND PROVIDE FOR CLEARING SKIES AND DIMINISHING WNDS. THIS
SHOULD BRING GOOD RADIATIONAL COOLING CONDITIONS TO NE WI AND
PREFER THE COOLER MAV GUID FOR MIN TEMPS. THE SFC HI OVR THE WRN
GREAT LKS AT THE START OF THE WORK WEEK WL GRADUALLY SLIDE TOWARD
THE ERN GREAT LKS BY MON NGT AND INTO THE MID-ATLANTIC STATES BY
TUE AFTERNOON. A PLEASANT...COMFORTABLE DAY FOR MON WITH NORMAL
TEMPS AND RELATIVELY LOW R.H.`S. AS WE GET ON THE BACKSIDE OF THE
DEPARTED HI PRES ON TUE...A WARMER/MORE MOIST AIRMASS TO RETURN TO
NE WI. HAVE KEPT BOTH MON AND TUE DRY.
ATTN TURNS TO THE NRN PLAINS/UPR MIDWEST WHERE A CDFNT IS PROGGED
TO SLOWLY BE MOVG SEWD. THERE ARE TIMING DIFFERENCES AMONG THE
MDLS WITH THE GFS RACING THE FNT THRU TUE NGT...THE ECMWF/UKMET
HOLDING THE FNT OFF TIL WED AND THE GEM EVEN SLOWER. THE ENSEMBLE
MEAN FAVORS THE ECMWF/UKMET SOLN SO PREFER TO BRING A SLGT CHC OF
SHWRS/TSTMS TO NE WI TUE NGT WITH CHC POPS THEN FOR WED AS THE FNT
APPROACHES.
BIG QSTNS REMAIN FOR THE LTR PART OF NXT WEEK WITH REGARDS TO THE
POSITIONING OF THE FNTL BNDRY. THE FNT IS EXPECTED TO SLOW DOWN OR
EVEN GRIND TO A HALT AS IT ENCOUNTERS THE SUBTROPICAL RDG. IT APRS
THAT THE FNT IS STILL IN OUR VCNTY THRU THU...THUS WL NEED TO
CARRY CHC POPS AT LEAST THRU THE END OF THU. AS AN UPR TROF DIGS
SWD TOWARD THE PAC NW BY NXT FRI AND A WEAK UPR RDG BUILDS OVR THE
ROCKIES...THE MEAN FLOW MAY TURN ENUF TO THE W-NW TO KICK THE FNT
FARTHER SOUTH. THAT BEING SAID...TIMNIG IS VERY SUSPECT THIS FAR
OUT. PREFER TO LINGER A SML POP THRU FRI UNTIL THIS TIMING ISSUE
CLRS UP. TEMPS FOR LATE IN THE WEEK SHOULD BE CLOSE TO NORMAL.
&&
.AVIATION...WARM FRONT WILL LIFT NORTH ACROSS THE AREA THIS EVG.
PATCHY MVFR CIGS MAY DEVELOP NORTH OF THIS BOUNDARY...ALONG WITH
SCT TSTMS. THUNDERSTORMS WILL INCREASE IN C/NC WI TOWARD MIDNIGHT
AS THE COLD FRONT APPROACHES FROM THE WEST. THESE STORMS ARE
EXPECTED TO WEAKEN SOMEWHAT AS THEY SHIFT EAST OVERNIGHT. THE
COLD FRONT WILL MOVE OUT THE FCST AREA SATURDAY MORNING...TAKING
ANY PCPN WITH IT. MUCH DRIER AIR WILL MOVE INTO THE RGN ON
SATURDAY...LEADING TO VFR CONDITIONS. GUSTY WEST WINDS ARE
EXPECTED SATURDAY AFTERNOON.
&&
.MARINE...HAVE ISSUED A SMALL CRAFT ADVISORY FOR TONIGHT INTO
SATURDAY MORNING. 925 MB WINDS INCREASE TO 40-45 KTS OVER LK MICH
TONIGHT...SO DESPITE THE STABLE MARINE LYR...S-SW WINDS SHOULD
INCREASE TO AT LEAST 15-25 KTS AFTER THE WARM FRONT MOVES THRU.
INCREASING GULF MOISTURE WILL LIKELY ALSO LEAD TO MARINE FOG
DEVELOPMENT TONIGHT. LOCALLY DENSE FOG IS PSBL.
&&
.GRB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
KIECKBUSCH/KALLAS
AREA FORECAST DISCUSSION...UPDATED
NWS GREEN BAY WI
1150 AM CDT FRI JUL 11 2008
.UPDATE...OVERNIGHT CONVECTION HAS PUSHED THE FRONTAL BOUNDARY WELL
TO OUR SOUTH...INTO N IL. THIS BOUNDARY WILL EVENTUALLY LIFT BACK TO
THE NORTH LATER THIS AFTERNOON AND EVG...BUT NOT TOO SURE HOW MUCH
CONVECTION WILL DEVELOP IN ASSOC WITH IT. ONE IMPORTANT FACTOR IS
POTENTIAL CAPPING...WHICH...ACCORDING TO MORNING RAOBS AND 15-16Z
TAMDAR SOUDINGS...HAS PUSHED INTO EASTERN MN AND WSTRN WI. MODELS
SHOW THE CAP BUILDING FARTHER EAST INTO WI DURING THE AFT/EVG.
MODIFIED RUC/NAM FCST SOUNDINGS FOR CNTRL WI AT 21Z (USING 84/67)
INDICATE CAPES AROUND 2000 J/KG...CINH 40-70 J/KG...AND HIGH WET
BULB ZERO HGTS OF AT LEAST 12K FT. WITH UNCERTAINTY INVOLVING THE
MOVMT OF THE WARM FRONT...AND WHETHER OR NOT WE`LL GET CAPPED THIS
AFTERNOON...PLAN TO JUST KEEP ISOLD THUNDERSTORMS IN THE FCST FOR
THE REST OF THE DAY.
WILL NEED TO MAKE SOME ADJUSTMENTS TO MAX TEMPS AS WELL.
KIECKBUSCH
&&
.PREV DISCUSSION...ISSUED AT 709 AM CDT FRI JUL 11 2008...
UPDATE...UPDATED TO EXPIRE THE FLASH FLOOD WATCH FOR CENTRAL
WISCONSIN. WILL LET THE URBAN SMALL STREAM CONTINUE. THE BIG EAU
PLEINE AND YELLOW RIVERS WILL NEED TO BE MONITORED THIS MORNING
FOR RISES.
TDH
DISCUSSION ISSUED AT 250 AM CDT FRI JUL 11 2008...
SHORT TERM...TODAY/TONIGHT/SATURDAY. FIRST CHALLENGE THIS AM DEALING
WITH APPROACHING CONVECTION FROM THE WEST. CONVECTION FOCUSING ON
INTERSECTION OF WARM FRONT AND CAPPING EDGE OVER WRN WI AND
GRADUALLY DEVELOPING NORTHWARD TWD EAU. MEANWHILE AT 07Z AN MCS
OVER EC MN WORKING TOWARD WRN WI EARLY THIS MORNING. AS A RESULT
EXPECT THE HEAVY CONVECTION FROM SE WI TO WRN WI TO EAU TO
CONTINUE AND EXPAND BEFORE DRIFTING INTO CENTRAL WI EARLY THIS
MORNING. WEAK H8 SW LLJ WILL CONTINUE TO FEED THIS LINE WITH
HIGHER PW AND UNSTABLE AIR. MODELS ATTEMPT TO LIFT THE WARM
FRONT NORTH OF THE FORECAST AREA LATER TODAY...BUT WITH THE SLOWER
WARM FRONT TREND AND THE CAP EDGE STILL WORKING OVER THE FA
TODAY...WILL KEEP AN ISOLD MENTION GOING OVER MOST LOCATIONS
THROUGH THIS EVENING...THEN INCREASE TO LIKELY POPS OVERNIGHT AS
THE CDFNT SLIDES OVER. WILL CONTINUE A MORNING CHC MENTION OVER EC
WI SAT MORNING UNTIL AS THE FRONT CONTINUES TO DRIFT EAST...THEN
DRIER AND COOLER AIR WILL FILTER INTO THE FA.
AS FAR AS SEVERE POTENTIAL...WITH LIGHT WIND PROFILES...MAINLY
LARGE HAIL AND HEAVY RAIN THIS AM AND THEN HAIL AND DAMAGING WINDS
WITH THE FROPA TONIGHT.
LONG TERM...SATURDAY NIGHT THROUGH THURSDAY.
HIGH PRESSURE WILL SLIDE ACROSS THE AREA SATURDAY NIGHT...
BRINGING MOSTLY CLEAR SKIES AND PLEASANT TEMPERATURES. WEAK
DISTURBANCE IS EXPECTED TO SWING ACROSS THE AREA SUNDAY...SO WILL
CONTINUE THE SMALL CHANCES OF SHOWERS. MODELS CONTINUE TO SHOW
DIFFERENCES IN HOW MUCH COOL AIR WILL WORK INTO THE
AREA...THEREFORE CONTINUED CURRENT FORECAST.
HIGH PRESSURE WILL BUILD INTO THE AREA SUNDAY NIGHT AND MONDAY.
12Z ECMWF AND 00Z GFS TONIGHT SHOW STRONG WARM ADVECTION MONDAY
NIGHT AT 850MB...COMBINED WITH STEEP 700/500 MB LAPSE RATES OF 7-
8 C/KM WARRANTS A CHANCE OF SHOWERS AND THUNDERSTORMS. SURROUNDING
FORECAST OFFICES REMAINED DRY...THEREFORE WILL NOT INTRODUCE A
CHANCE OF SHOWERS AND STORMS. WILL PASS ON TO THE DAY SHIFT.
AREA WILL BE SUNNY AND WARM TUESDAY AS COLD FRONT APPROACHES FROM
THE WEST LATE IN THE DAY. 00Z GFS APPEARS QUICKER THAN 12Z
RUN...SO DAY SHIFT MAY NEED TO ADJUST TIMING OF FRONT ON THE DAY
SHIFT WITH FRONTAL PASSAGE ON WEDNESDAY. MAX TEMPERATURES
WEDNESDAY AND THURSDAY MAY NEED TO BE ADJUSTED AS WELL.
AVIATION...EXPECT SHOWERS AND THUNDERSTORMS TO BECOME WIDESPREAD
OVER CENTRAL WI THROUGH 18Z ALONG A WARM FRONT THEN BECOME SCT
BETWEEN 18Z TO AROUND 04Z AS THE WARM FRONT LIFTS NORTH. THUNDERSTORMS
AGAIN WILL BE ON THE INCREASE AFTER 04Z AS A COLD FRONT SWEEPS
OVER THE REGION. AREA OF IFR CIGS WILL CONTINUE TO EXPAND OVER NE
WI NORTH OF THE WARM FRONT THIS MORNING.
HYDROLOGY...ISSUED A SHORT FUSE FLASH FLOOD WATCH UNTIL 7 AM
THIS MORNING TO HANDLE THE INTERSECTION OF THE CONVECTION OVER
CLARK COUNTY AND THE UPSTREAM MCS OVER MN APPROACHING THIS SAME
AREA. LOCATION OF THE CAP EDGE...WARM FRONT AND SW H8 WINDS
MOVING SOME HIGHER PW AND UNSTABLE AIR TWD CENTRAL WI BETWEEN 2 AM
AND 4 AM. RELYING ON MCS TO HELP LIFT THIS BAND OF TSTMS NORTH
INTO CENTRAL WI. IF THIS SCENARIO DOES NOT DEVELOP...WILL CANCEL
THE WATCH AT 7 AM...OR ON THE OTHER HAND IF THE SCENARIO PANS OUT
WILL BE ISSUING VARIOUS FLOOD ADVISORIES OR WARNINGS BY 7 AM.
&&
.GRB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
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