Forecast Discussions mentioning "ACARS", "MDCRS", "AIRCRAFT", "TAMDAR", or "AMDAR" received at FSL on 06/04/07


SOUTHWEST CALIFORNIA AREA FORECAST DISCUSSION
NWS LOS ANGELES/OXNARD CA
815 PM PDT SUN JUN 3 2007 .SHORT TERM...(TONIGHT-WED) SATELLITE IMAGERY SHOWING A QUICK RETURN OF LOW CLOUDS AND FOG INTO COASTAL AREAS OF LOS ANGELES AND VENTURA COUNTIES. WITH SOME WEAK UPPER LEVEL RIDGING THERE HAS BEEN SOME LOWERING AND STRENGTHENING OF THE MARINE INVERSION. THE CURRENT MARINE LAYER DEPTH RANGES BETWEEN 1500 AND 1800 FEET. COMBINATION OF STRENGTHENING MARINE INVERSION WITH STRONG ONSHORE FLOW WILL COTINUE TO MAKE CLEARING DIFFICULT ACROSS SOME OF THE IMMEDIATE COASTAL AREAS ON MONDAY. WARMING TREND ALREADY UNDERWAY TODAY ACROSS MOST INLAND LOCATIONS... WITH LANCASTER AND OZENA REACHING THE 100 DEGREE MARK. LOOK FOR TEMPERATURES TO NUDGE UPWARD A COUPLE OF MORE DEGREES IN MOST AREAS ON MONDAY. HOWEVER IMMEDIATE COASTAL AREAS WILL REMAIN QUITE COOL DUE TO INFLUENCE OF MARINE LAYER CLOUDS AND STRONG ONSHORE FLOW. A MODERATE NORTHWEST PRESSURE GRADIENT IS EXPECTED TO DEVELOP ACROSS THE SBA COUNTY MOUNTAINS ON MONDAY NIGHT WHICH WILL BRING A PREVIEW OF GUSTY WINDS TO THE PASSES AND CANYONS OF THE SANTA YNEZ RANGE. OTHER WIND CONCERN WILL CONTINUE TO BE GUSTY ONSHORE WINDS MONDAY AFTERNOON AND EVENING ACROSS THE ANTELOPE VALLEY AND LA COUNTY MOUNTAINS...ESPECIALLY THROUGH THE INTERSTATE 14 CORRIDOR. THESE GUSTY ONSHORE WINDS COMBINED WITH VERY WARM TEMPERATURES AND HUMIDITY LEVELS LOCALLY FALLING INTO SINGLE DIGITS WILL CREATE HEIGHTENED FIRE WEATHER CONCERNS ACROSS THE LA COUNTY MOUNTAINS AND ANTELOPE VALLEY. *** FROM PREVIOUS DISCUSSION *** FOR TUESDAY...TEMPS WILL START TO LOWER AS LARGE BROAD UPR LVL TROF BEGINS TO PUSH DOWN INTO CALIFORNIA. INLAND TEMPS SHOULD DROP AT LEAST 10 DEGREES IN SOME MOUNTAIN AND DESERT REGIONS. VALLEYS SHOULD LOWER INTO THE 70S TO LOWER 80S. COASTAL AREAS WILL EXPERIENCE A SLIGHT COOLING TREND SINCE IT REMAINS UNDER THE MARINE INFLUENCE. AS UPPER LEVEL TROF CONTINUES TO SWING THROUGH CALIFORNIA...H5 HEIGHTS AND THICKNESS LEVELS WILL CONTINUE TO LOWER SIGNIFICANTLY ON WEDNESDAY. THIS WILL TRANSLATE INTO HIGHS ONLY NEAR 80 IN THE ANTELOPE VALLEY WITH HIGHS ONLY REACHING IN THE 70S IN MOST VALLEY LOCATIONS THIS PATTERN WILL CONTINUE THROUGH THURSDAY. 850 MB TEMPS WILL DIVE DOWN TO LESS THAN 10 DEGREES CELSIUS TUESDAY NIGHT THROUGH WED NIGHT. THIS SHOULD HELP TO SCOUR OUT ANY LOW CLOUDS N OF POINT CONCEPTION BUT FEEL THAT EDDY WILL WIN THE WAR SOUTH OF POINT CONCEPTION...ALTHOUGH SOME GUSTY NW TO W WINDS WILL BE POSSIBLE ACROSS PORTIONS OF VENTURA COUNTY TUE NIGHT. EXPECTING STRONGER SUNDOWNER TYPE WINDS ACROSS THE SANTA BARBARA COUNTY MOUNTAINS AND SOUTH COAST TUE NIGHT. STRONG NORTHWEST TO NORTHERLY WINDS COULD ALSO AFFECT THE INTERSTATE 5 CORRIDOR TUE NIGHT AND ONCE AGAIN WEDNESDAY. LATER SHIFTS WILL HAVE TO MONITOR TO FOR POTENTIAL WIND ADVISORIES FOR THESE LOCATIONS TUE AND WED. .LONG TERM...(THURSDAY-SUNDAY) BOTH GFS AND ECMWF ARE IN GOOD AGREEMENT WITH THE PLACEMENT OF LARGE BROADSCALE UPPER LVL TROF THAT WILL CONTINUE TO REMAIN OVER THE AREA THROUGH AT LEAST FRIDAY. THIS WILL KEEP TEMPS COOLER THAN NORMAL THROUGH THE PERIOD. TEMPS SHOULD REBOUND SOME ON SAT AND SUN AS 500 MB HEIGHTS BEGIN TO REBOUND. EXPECT TYPICAL JUNE GLOOM PATTERN TO CONTINUE THROUGH SUNDAY. && AVIATION...04/0300Z LATEST ACARS DATA SHOWING MARINE LAYER DEPTH AROUND 1500 FEET WHILE 00Z VANDENBERG SOUNDING INDICATING DEPTH AROUND 1800 FEET. WITH STRONG ONSHORE FLOW IN PLACE...MARINE LAYER SHOULD STILL BE SUFFICIENTLY DEEP TO SPREAD INTO MANY VALLEY AREAS OVERNIGHT. LOOK FOR CEILINGS TO GENERALLY RANGE BETWEEN 600 AND 1000 FEET AT KLAX THROUGH MONDAY MORNING...WITH LITTLE OR NO BURNOFF OF STRATUS EXPECTED ONCE AGAIN MONDAY AFTERNOON. WITH LOW CLOUDS AND FOG ALREADY REACHING THE SEPULVEDA PASS AREA AS OF 03Z...IT APPEARS THAT LOW CLOUDS AND FOG WILL LIKELY SPREAD INTO KBUR AND KVNY SOMETIME BETWEEN 06Z AND 07Z. WITH LOWERING AND STRENGTHENING OF MARINE INVERSION...WILL HAVE TO WATCH FOR POSSIBILITY OF IFR CEILINGS/VSBYS ACROSS PORTIONS OF THE VALLEYS OVERNIGHT INTO MONDAY MORNING...INCLUDING KBUR. $$ .LOX WATCHES/WARNINGS/ADVISORIES... SMALL CRAFT ADVISORY (SEE LAXCWFLOX). && $$ PUBLIC...GOMBERG/KAPLAN AVIATION...GOMBERG WWW.WEATHER.GOV/LOSANGELES
AREA FORECAST DISCUSSION
NWS SAN DIEGO CA
100 PM PDT SAT JUN 2 2007 .SYNOPSIS... HIGH CLOUDS ASSOCIATED WITH A WEAK UPPER LEVEL TROUGH WILL DRIFT EAST TONIGHT...WHILE LOW CLOUDS WILL SURGE BACK INTO THE INLAND VALLEYS. BUILDING HIGH PRESSURE SUNDAY AND MONDAY WILL BRING WARMING ALONG WITH A SHALLOWER MARINE LAYER. ON TUESDAY A TROUGH ALONG THE WEST COAST WILL BRING COOLING AND THE RETURN OF A DEEPER MARINE LAYER THE LATTER HALF OF NEXT WEEK. && .DISCUSSION...FOR EXTREME SOUTHWESTERN CALIFORNIA INCLUDING ORANGE... SAN DIEGO...WESTERN RIVERSIDE AND SOUTHWESTERN SAN BERNARDINO COUNTIES... THE BACK EDGE OF A THICK HIGH CLOUD SHIELD OVER SOUTHERN CALIFORNIA INCHED SLOWLY EASTWARD THIS AFTERNOON. THE WARMING CLOUD TOP TREND SHOWN ON THE IR LOOP WILL CONTINUE THROUGH THE EVENING AS THE UPPER TROUGH MOVES EAST AND COLLAPSES. THESE THICK HIGH CLOUDS PREVENTED STRONG SOLAR HEATING FROM OCCURRING...AND LIMITED THE MIXING OUT OF THE MARINE LAYER IN SAN DIEGO COUNTY WHERE TEMPS WERE LOWER. FARTHER NORTH THE INLAND EMPIRE CLEARED QUICKLY AND TEMPS WERE A FEW DEGREES HIGHER THAN YESTERDAY. A WEAK COASTAL EDDY WILL KEEP THE MARINE LAYER DEPTH NEAR 2000 FEET TONIGHT WITH CLOUDS ROLLING BACK INTO THE SAN DIEGO VALLEYS AND WESTERN INLAND EMPIRE. BUT OVER THE NEXT TWO DAYS THE MARINE LAYER WONT REACH AS FAR INLAND AS HIGH PRESSURE BUILD ALOFT. 850 MB TEMPS THAT WERE AT 21C TODAY INCREASE TO 23C SUNDAY AND 24C MONDAY...AND TEMPS WILL BE 5 TO 10 DEGREES HIGHER IN THE VALLEYS...MTNS AND DESERTS THROUGH MONDAY. THE COASTAL ZONES WILL ALSO BE A LITTLE WARMER...BUT THE STRONGER INVERSION MAY KEEP LOW CLOUDS ALONG THE COAST EACH AFTERNOON. IN THE LONG TERM...THE GFS CONTINUES ITS TREND OF SLIDING A FAIRLY POTENT PACIFIC SHORTWAVE ACROSS CENTRAL CALIFORNIA TUESDAY AFTERNOON...THEN ACROSS SOUTHERN NEVADA WEDNESDAY MORNING. THIS TROUGH WILL BRING COOLER WEATHER...STRONG NW WINDS IN THE MOUNTAINS AND DESERTS...AND A MUCH DEEPER MARINE LAYER. THURSDAY THROUGH SATURDAY...MEAN FLOW ALOFT REMAINS CYCLONIC AS SERIES OF PACIFIC SHORTWAVES MAKE LANDFALL OVER THE PACIFIC NORTHWEST. THE MARINE LAYER WILL REMAIN DEEP...TEMPS WILL AVERAGE SLIGHTLY BELOW AVERAGE...AND THE AFTERNOONS AND EVENINGS WILL BE BLUSTERY IN THE MOUNTAINS AND DESERTS. && .AVIATION...021900Z MDCRS DATA INDICATES THE MARINE LAYER HAD DEEPENED TO AROUND 3000 FEET SINCE EARLY THIS MORNING BUT HAD DROPPED BACK DOWN TO AROUND 2500 FEET SINCE. STRATUS CONTINUES TO HANG TOUGH IN THE COASTAL AREAS DUE TO LACK OF SOLAR HEATING CAUSED BY THE THICK HIGH CLOUDS. LATEST SATELLITE IR LOOP INDICATES THE HIGHER CLOUDS ARE THINNING WHICH SHOULD ALLOW FOR MORE SOLAR HEATING FOR SOME BURN OFF NEAR THE COAST THIS AFTERNOON. EXPECT THE STRATUS WITH BASES AROUND 1500 FEET MSL TO PUSH BACK INLAND DURING THE EVENING REACHING THE FAR INLAND VALLEY AREAS BEFORE MIDNIGHT. EARLIER CLEARING IS EXPECTED ON SUNDAY SINCE HIGH CLOUDS SHOULD NOT BE A FACTOR. ABOVE THE MARINE LAYER...CONTINUED VFR CONDITIONS WITH CEILINGS ABOVE FL200 AND UNRESTRICTED VISIBILITIES THROUGH SUNDAY. && .SGX WATCHES/WARNINGS/ADVISORIES... CA...NONE. PZ...NONE. && $$ PUBLIC...MOEDE AVIATION/MARINE...HORTON NWS ON THE WEB AT WEATHER.GOV/SANDIEGO
AREA FORECAST DISCUSSION
NWS SAN DIEGO CA
900 AM PDT SAT JUN 2 2007 .SYNOPSIS... HIGH CLOUDS FROM A WEAK UPPER LEVEL TROUGH WILL DRIFT OVERHEAD TODAY. BUILDING HIGH PRESSURE SUNDAY AND MONDAY WILL BRING WARMING ALONG WITH A SHALLOWER MARINE LAYER. ON TUESDAY A TROUGH ALONG THE WEST COAST WILL BRING COOLING AND A DEEPER MARINE LAYER FOR THE LATTER HALF OF NEXT WEEK. && .DISCUSSION...FOR EXTREME SOUTHWESTERN CALIFORNIA INCLUDING ORANGE... SAN DIEGO...WESTERN RIVERSIDE AND SOUTHWESTERN SAN BERNARDINO COUNTIES... SATELLITE LOOP SHOWS A SWATH OF MID AND HIGH CLOUDS OFF THE SAN DIEGO COAST DRIFTING NE. THE 12Z SOUNDING AND THE TIME-HEIGHT CROSS SECTIONS SHOW THE BASE OF THE MOIST LAYER AROUND 20000 FEET WITH THE MOISTURE EXTENDING UPWARD TO 30000 FEET...AND WITH THEIR CURRENT SPEED (19KTS) THE MID AND HIGH CLOUDS WILL PREVAIL THROUGH THE DAY. EARLY MORNING SURGE OF THE MARINE LAYER PUSHED LOW CLOUDS INTO THE SAN DIEGO VALLEYS AND WESTERN SECTIONS OF THE INLAND EMPIRE. THE INVERSION IS A LITTLE LOWER THAN YESTERDAY AND OF SIMILAR STRENGTH. EXPECT A SLOW BURNOFF TOWARD THE COAST THROUGH THE DAY...WITH THE LOW CLOUDS NOT QUITE CLEARING COMPLETELY FROM SOME OF THE BEACHES. THE HIGH CLOUDS WILL BE THINNER TOMORROW AS THE UPPER TROUGH MOVES INLAND. HIGH PRESSURE REBUILDS OVER THE SOUTHWEST THROUGH MONDAY WITH HEIGHTS INCREASING TO 589 DM...UP FROM THE CURRENT 583 DM. THIS WILL LEAD TO WARMING ABOVE THE MARINE LAYER THROUGH MONDAY WITH HIGHS 5 TO 10 DEGREES WARMER THAN TODAY IN THE VALLEYS...MTNS AND DESERTS. THE COASTAL ZONES WILL ALSO BE A LITTLE WARMER...BUT THE WARMING ALOFT STRENGTHENING THE INVERSION...THE LOW CLOUDS MAY BE SLOWER TO CLEAR NEAR THE COAST EACH AFTERNOON. ...FROM PREVIOUS DISCUSSION... .LONG TERM (TUESDAY THROUGH FRIDAY)... MODELS ARE TRENDING STRONGER AND FARTHER SOUTH WITH LOW PRESSURE MOVING INLAND ALONG THE WEST COAST. THIS WILL BRING COOLING TO SOUTHWEST CALIFORNIA TUESDAY THROUGH THURSDAY WITH STRONGER ONSHORE FLOW BRINGING STRONGER AFTERNOON AND EVENING WINDS TO THE MOUNTAINS AND DESERTS EACH DAY. THIS TROUGH...IN COMBINATION WITH A PERSISTENT COASTAL EDDY...WILL BRING A DEEPER MARINE LAYER. BY WEDNESDAY AND THURSDAY...DAYTIME CLEARING WEST OF THE MOUNTAINS COULD BE QUITE SLOW...VERY TYPICAL FOR EARLY JUNE. BY THE END OF THE WEEK...THE TROUGH BEGINS TO WEAKEN. THIS SHOULD ALLOW FOR A LOW WARMING TREND AND SLOWLY DECREASING MARINE LAYER. && .AVIATION...021500Z 12Z NKX SOUNDING AND MORNING MDCRS SOUNDINGS INDICATE THE MARINE LAYER DEPTH WAS AROUND 2200 FEET. ONLY MINOR CHANGES IN THE MARINE LAYER DEPTH IS EXPECTED THROUGH SUNDAY. STRATUS...WITH BASES AROUND 1500 FEET MSL...SHOULD CLEAR TO THE COAST BETWEEN 16 AND 18Z. STRATUS SHOULD PUSH BACK ONTO THE COAST BETWEEN 22Z AND 00Z THEN INLAND DURING THE EVENING REACHING THE INLAND VALLEYS BY MIDNIGHT. A SIMILAR CLEARING PATTERN IS EXPECTED ON SUNDAY. ABOVE THE MARINE LAYER...CONTINUED VFR CONDITIONS WITH CEILINGS ABOVE FL200 AND UNRESTRICTED VISIBILITIES THROUGH SUNDAY. && .SGX WATCHES/WARNINGS/ADVISORIES... CA...NONE. PZ...NONE. && $$ PUBLIC...MOEDE AVIATION/MARINE...HORTON NWS ON THE WEB AT WEATHER.GOV/SANDIEGO

AREA FORECAST DISCUSSION
NWS GRAND RAPIDS MI
1048 AM EDT SAT JUN 2 2007 .UPDATED... I LOWERED THE POP THIS AFTERNOON OVER ALL OF THE CWA TO CHC SINCE I DO NOT SEE ANY REAL MECHANISM FOR THUNDERSTORM GENERATION OTHER THEN THE LAKE BREEZE BOUNDARY INTRACTION. TRUE...THERE ARE DECENT CAPES AND THE SURFACED BASED LI VALUES WILL BE NEGATIVE OVER JUST ABOUT ALL OF THE CWA. EVEN SO...THE DNVA BEHIND THE EARLY MORNING CONVECTION SHOULD SUPPRESS CONVECTION INTO MID AFTERNOON. MEANWHILE SHORTWAVE ENERGY NEAR CHI AT 15Z MAY AID LAKE BREEZE CONVECTION NEAR US-131 BY MID AFTERNOON. DUE TO THE LAKE BREEZE INTERACTION WITH THE SHORTWAVE THIS AFTERNOON I DO HAVE LIKELY POP NEAR US-131 BY MID AFTERNOON. THAT CONVECTION WILL LIKELY MOVE INLAND THIS EVENING BEFORE WEAKENING WITH THE LOSS OF SOLAR ENERGY. THUS I KEEP THE NUMEROUS WORDING EARLY EVENING HOURS FOR THUNDERSTORMS. AS FOR SEVERE THUNDERSTORMS...CAPES ARE IMPRESSIVE BUT THE WIND FIELD THROUGH MID LEVELS IN NOT CONDUCIVE TO SEVERE WEATHER. FREEZING LEVELS ON TAMDAR AT 12-14Z ARE SLOPE UP FROM 12000 FT NEAR JXN TO 1300 FT NEAR THE LAKE MICHIGAN SHORE. THE HIGH FREEZING LEVELS AT FIRST GLANCE WOULD NOT SUPPORT HAIL. HOWEVER...MODEL FORECAST SOUNDING SUGGEST PULSE LARGE HAIL IS NOT OUT OF THE QUESTION SINCE BASED ON THE RUC MODEL SOUNDINGS THERE IS A FAIR AMOUNT OF CAPE ABOVE THE -10C LEVEL. THE NAM IS MORE CONSERVATIVE. THE BIG QUESTION IS WILL THE LOW LEVEL DEW POINTS LOWER THIS AFTERNOON AS DEEPER MIXING OCCURS. IF SO ALL BETS OF OFF FOR ANY SEVERE WEATHER OVER THE GRR CWA TODAY OR TONIGHT. THE REST OF THE ZONE FORECAST SEEMS TO BE ON TRACK... SO THAT REMAINS AS IS. .PREVIOUS DISCUSSION... WV IMAGERY THIS MORNING SHOWS THE UPPER LOW CONTINUING TO SPIN OVER THE PLAINS STATES EARLY THIS MORNING. THE LOW IS CURRENTLY CENTERED OVER THE ERN BORDER OF SOUTH DAKOTA AND NEBRASKA. AHEAD OF THE UPPER LOW IS A NICE BELT OF DEEP SW FLOW WITH EMBEDDED SHORT WAVES RIDING TO THE NE. OUR MAIN CONCERN IN THE SHORT TERM PORTION OF THE FORECAST IS PCPN CHCS AND SEVERE POTENTIAL FROM TODAY RIGHT ON THROUGH MON AS THE UPPER LOW MOVES TOWARD THE AREA THROUGH SUN AND IS THEN RIGHT OVERHEAD LATE SUN INTO MON. REMNANTS OF THE LINE OF CONVECTION THAT AFFECTED AREAS TO OUR WEST OVER IA/IL/WI DURING THE DAY ON FRI...ARE CURRENTLY MOVING THROUGH THE CWFA THIS MORNING. THE CONVECTION HAS DIMINISHED SIGNIFICANTLY... HOWEVER DUE TO MESOSCALE EFFECTS AND AN INSTABILITY AXIS ALOFT... SOME OF THE CONVECTION HAS MAINTAINED ITSELF AS IT MOVES NE. THIS BATCH OF CONVECTION WILL MOVE EAST OF THE CWFA BY 12Z...LEAVING THE AREA IN A RELATIVE VOID OF MOST PCPN TEMPORARILY. CLOUDS SHOULD BE SOMEWHAT LIMITED THIS MORNING WITH DEBRIS FROM UPSTREAM CONVECTION RESPONSIBLE MOST CLOUD COVER INITIALLY. BREAKS IN THE CLOUDS MAY ALLOW FOR SOME FOG TO DEVELOP WITH THE HIGHER DEW POINTS IN PLACE...ESPECIALLY AT LOCATIONS THAT HAVE SEEN SOME RAIN THIS MORNING. AFTER ANY FOG DISSIPATES...SOME SUN WILL HELP WARM TEMPS BACK INTO THE 80S ACROSS MOST OF THE CWFA. SUN WILL BE SOMEWHAT LIMITED AFTER THE MORNING AS ADDITIONAL DEBRIS CLOUD COVER FROM CONVECTION SW OF THE AREA WILL STREAM INTO THE AREA. ADDITIONAL WAVES THAT CAN BE SEEN FROM LOWER MICHIGAN BACK DOWN INTO THE MO AREA WILL TEND TO MOVE TOWARD THE AREA THIS MORNING. HOW MUCH WE DESTABILIZE OBVIOUSLY HAS TO DO WITH HOW MUCH SUN WE CAN GET...AND THIS DEPENDS ON THE TIMING OVER UPSTREAM SHORT WAVES. ASSUMING WE CAN GET A FAIR AMOUNT OF SUN THIS MORNING...MODIFIED FCST SOUNDINGS FOR THIS AFTERNOON WITH TEMPS IN THE MID 80S AND DEW POINTS IN THE LOW TO MID 60S WOULD SUPPORT SB CAPES AROUND 2000 J/KG AND SB LI/S AROUND -5. WITH SHORT WAVES EXPECTED TO BEGIN MOVING ACROSS THE AREA LATER TODAY AS THE UPPER LOW APPROACHES THE AREA...THIS SUPPORTS A BETTER THREAT OF CONVECTION THAN WHAT HAS BEEN PRESENT THE PAST FEW DAYS. DEEP LAYER SHEAR ON A SYNOPTIC SCALE IS NOT VERY IMPRESSIVE FOR MOST OF THE DAY AS MID LEVEL WINDS ARE ONLY 25 TO 30 KTS GIVING SHEAR VALUES OF 20 KTS OR SO. DEEP LAYER SHEAR DOES INCREASE LATE FROM THE NW AS THE MID LEVEL JET MOVES IN. ALSO IF ANY CONVECTIVELY INDUCED VORT MOVES IN...THERE WOULD BE SOME GOOD LOCALIZED SHEAR PRESENT. POTENTIAL INSTABILITY COULD MAKE UP FOR THIS AND PRODUCE A WIND AND HAIL THREAT...ESPECIALLY LATER AS THE SHEAR INCREASES. WE HAVE INCREASED THE POPS IN THE AFTERNOON AND EVENING HOURS TO THE LIKELY/NUMEROUS CATEGORY. WITH THE LOSS OF DIURNAL INSTABILITY...THE THREAT OF WIDESPREAD STORMS AND SEVERE WEATHER WILL DIMINISH BY THE OVERNIGHT HOURS. THE THREAT OF SHOWERS AND STORMS WILL REMAIN THOUGH WITH THE AREA REMAINING PRONE TO SHORT WAVES RIDING NE ALONG THE MID LEVEL FLOW. WE HAVE TRENDED POPS LOWER FOR THE SECOND HALF OF THE NIGHT TONIGHT. THE UPPER LOW WILL THEN FINALLY MOVE NEARBY DURING THE COURSE OF THE DAY ON SUN ALONG WITH THE ASSOCIATED SFC FRONT. A FEW PEEKS OF SUN WILL BE POSSIBLE SUN MORNING...BUT WITH THE COLD POOL ALOFT MOVING OVERHEAD AND PLENTY OF LOW LEVEL MOISTURE...BREAKS IN THE CLOUDS WILL FILL IN AND SHOWERS AND STORMS WILL BEGIN DEVELOPING. INSTABILITY WILL NOT BE AS FAVORABLE AS SFC TEMPS WILL ONLY RISE INTO THE 70S. HOWEVER DEW POINTS STILL IN THE 50S AND LOWER 60S WILL ACT WITH COLD POOL ALOFT TO PROVIDE AROUND 1000 J/KG OF SB CAPE AND LI/S AROUND -3. DEEP LAYER SHEAR WILL BE MUCH BETTER WITH THE MID LEVEL JET MOVING OVERHEAD DURING THE DAY. SEVERE HAIL WILL BE POSSIBLE DUE TO FREEZING LEVELS OF ONLY AROUND 9K TO 10K FEET...AND SOME DOWNBURSTS WILL BE POSSIBLE WITH THE BETTER ORGANIZED STORMS. THE POTENTIAL OF PCPN WILL THEN DIMINISH SOMEWHAT ON MON AS THE UPPER LOW FINALLY OPENS UP INTO A WAVE AND THE BETTER MOISTURE MOVES EAST OF THE AREA. A FEW INSTABILITY SHOWERS WILL BE POSSIBLE MON AFTERNOON. THUNDER WILL REMAIN POSSIBLE AS THE COLD POOL ALOFT REMAINS OVERHEAD AND LI/S REMAIN SLIGHTLY NEGATIVE. TEMPS ON MON WILL LIKELY ONLY WARM INTO THE MID 60S TO LOWER 70S WITH THE THERMAL TROUGH MOVING IN. .LONG TERM... MON THROUGH FRI...MID AND UPPER LEVEL CYCLONIC FLOW CONTINUES THROUGH TUE WITH BUILDING HEIGHTS LATE ON TUE INTO THU AS WRN RIDGE BUILD EWD. ON TUE LATEST GFS/ECMWF SHOWING WEAK S/W ENERGY MOVING THROUGH TROF...SO THINKING IS FOR SCT SHOWER THREAT ESPECIALLY WITH AFTN DIURNAL HEAT MAX. TEMPS WILL START OUT BELOW NORMAL AND TREND UPWARDS TOWARDS THU. BY THU EARLY AM WARM FRONT PUSHES INTO AREA WITH S/W ENERGY DIGGING ESE AS IT TOPS RIDGE AXIS ALOFT. THIS WOULD BE A GOOD SCENARIO FOR EARLY MORNING MCS EVENT. BUMPED POPS A FEW PERCENT TO START A TREND TOWARDS POTENTIAL EVENT. $$ .GRR WATCHES/WARNINGS/ADVISORIES...NONE && $$ NJJ COBB WDM
AREA FORECAST DISCUSSION
NWS DETROIT/PONTIAC MI
101 AM EDT SAT JUN 2 2007 .AVIATION... AMPLE LOW LEVEL MOISTURE WILL LEAD TO MOSTLY MVFR VISIBILITIES IN HAZE/FOG THROUGH AT LEAST 16Z BEFORE INCREASING SOUTHWESTERLY WINDS ADD A LITTLE MIXING TO THE BOUNDARY LAYER. AT THIS TIME...WILL KEEP SHOWERS AND THUNDERSTORMS OUT OF THE TAFS UNTIL LATE AFTERNOON/EARLY EVENING. CONDITIONS LOOK A LITTLE MORE CONDUCIVE TO THUNDERSTORM DEVELOPMENT SAT AFTERNOON IN COMPARISON TO THE LAST TWO DAYS DUE TO HIGHER INSTABILITY AND A WEAKER MID LEVEL CAPPING INVERSION. && .PREV DISCUSSION...ISSUED 957 PM EDT FRI JUN 1 2007 UPDATE... THE KDTX RADAR SHOW ONLY A COUPLE LINGERING SHOWERS ACROSS SE MI. THE 00Z DTX SOUNDING SHOWS A CAPPING INVERSION NEAR 600MB...WHICH HAS PREVENTED THUNDERSTORM DEVELOPMENT OVER SE MI THIS AFTERNOON AND EVENING. AN AREA OF THUNDERSTORMS...CURRENTLY MOVING ACROSS WESTERN LAKE MICHIGAN IS ASSOCIATED WITH A MID LEVEL SHORT WAVE OVER EASTERN WISCONSIN. THIS WAVE IS FORECAST TO LIFT NORTH- NORTHEAST TONIGHT...WITH THE CONVECTION OVER LAKE MICHIGAN FORECAST TO WEAKEN AS IT MOVES INTO A LESS FAVORABLE ENVIRONMENT. THE WATER VAPOR LOOP DOES SHOW A POCKET OF MID LEVEL DRY AIR OVER SE MI...WITH THE LEADING EDGE OF DEEPER MOISTURE NOW MOVING ACROSS SW LOWER MI. THIS SUPPORTS LATEST MODEL GUIDANCE WHICH SHOWS AN AXIS OF MOISTURE CONVERGENCE BETWEEN 925MB AND 850MB WORKING ACROSS SE MI BETWEEN 06Z AND 12Z. THIS SEEMS TO WARRANT HOLDING ONTO ISOLATED SHOWERS IN THE FORECAST THROUGH THE NIGHT AND INTO EARLY SAT MORNING. MODEL SOLUTIONS ALSO HINT AT SOME MID LEVEL COOLING TOWARD 12Z...WHICH MAY STILL PROVIDE A CHANCE FOR ISOLATED THUNDERSTORMS BY EARLY MORNING. WILL ISSUE AN UPDATE TO CARRY ISOLATED SHOWERS ACROSS THE ENTIRE FORECAST AREA THROUGH THE NIGHT. ALSO...WITH SURFACE DEWPOINTS IN THE LOWER 60S AND GIVEN CURRENT TEMPERATURE TRENDS...HAVE INCREASED OVERNIGHT MINS A COUPLE DEGREES. PREV DISCUSSION...ISSUED 409 PM EDT FRI JUN 1 2007 SHORT TERM...REST OF TODAY AND TONIGHT ALL THAT IS LEFT OF MORNING CLOUDS IS A THIN CIRRUS SHIELD THAT WILL VACATE THE PREMISES THE NEXT FEW HOURS. IN TOW OF THE MORNING ACTIVITY...DIURNAL CUMULUS HAS DEVELOPED IN EARNEST WITH ABUNDANT BOUNDARY LAYER MOISTURE. THE FORECAST CHALLENGE REMAINS ON THUNDERSTORM DEVELOPMENT THIS AFTERNOON AND EVENING. AS HAS BEEN SEEN THE PAST FEW DAYS ANY FOCUS FOR ISOLATED/SLIGHT CHANCE OF THUNDERSTORMS WILL BE TIED TO THE LAKE BREEZE AND ANY OUTFLOW BOUNDARIES. WHAT IS DIFFERENT TODAY THOUGH IS AN OLD WASHED OUT /OCCLUDED FRONT THAT HAS MADE ITS WAY INTO CENTRAL MICHIGAN FROM THE LARGE EYE CATCHING UPPER LEVEL VORTEX CENTERED OVER DEWEY COUNTY SOUTH DAKOTA. CELLS HAVE BEEN TRYING TO DEVELOP...TO NO AVAIL...ALONG THIS BOUNDARY FROM SHIAWASSEE...SAGINAW...TUSCOLA COUNTIES. TWO AGREEABLE TAMDAR SOUNDINGS HAVE GIVEN GOOD CONFIDENCE OF A CAPPING ENVIRONMENT...ROUGHLY 875-800 MB ACROSS SOUTHEASTERN MICHIGAN. THIS SHOULD REMAIN THE CASE FOR DEWPOINTS THAT REMAIN IN THE LOW 60S. ELEVATED INSTABILITY DOES EXIST BUT WITH A MAX WIND OF 20 KNOTS IN THE ATMOSPHERIC COLUMN AND NOTHING IN THE WAY OF A LOW LEVEL JET...HARD TO FIND ANY FORCING/SUPPORT TO REALIZE THE INSTABILITY. AS A RESULT HAVE BACKED DOWN ON ISOLATED SHOWER AND THUNDERSTORM MENTION TO THAT OF SLIGHT CHANCE. WITH WEAK 0-6KM BULK SHEAR OF LESS THAN 20 KNOTS AND MIXED LAYER CAPE VALUES OF LESS THAN 1000 J/KG SEVERE POTENTIAL OF ANY DEVELOPMENT WILL BE MINIMAL. OVERNIGHT...COMPLEX CURRENTLY FIRING ACROSS EASTERN IOWA/WESTERN ILLINOIS WILL CONTINUE LIFTING NORTHWARD AROUND THE NORTHERN PLAINS VORTEX. THIS WILL KEEP GREATEST MOISTURE AND PRECIPITATION CHANCES ACROSS LAKE MICHIGAN AND THE FAR WESTERN LOWER PENINSULA TOWARDS DAYBREAK. A LOW LEVEL JET MAX PUSHING 30 KNOTS WILL HELP FEED THIS DEVELOPMENT THROUGHOUT THE NIGHT. WILL KEEP A SLIGHT CHANCE OF THUNDERSTORMS OVERNIGHT FOR THE FAR WESTERN CWA AS A BUFFER TO SURROUNDING CWA/S BUT FEEL MOST AREAS WILL REMAIN DRY PRIOR TO THE ENDING OF THIS FORECAST PERIOD. CLOUD COVER IS EXPECTED TO WANE WITH LOSS OF DAYTIME HEATING BUT INCREASE AGAIN AS IA/IL ACTIVITY PUSHES EASTWARD. WITH THE RELATIVELY HIGH DEWPOINTS AND INSULATING CLOUD COVER WILL LEAVE MINS IN THE 60S FOR MOST AREAS...MID 60S IN THE DETROIT HEAT ISLAND. LONG TERM...SATURDAY THROUGH FRIDAY ON SATURDAY...FORECAST SOUNDINGS ACROSS THE SOUTH HALF OF THE CWA LOOK VERY MUCH LIKE SOUNDINGS OBSERVED THROUGHOUT THIS PREVIOUS WEEK. OVERALL NOT THAT MOIST...WEAK OVERALL DYNAMICS (VERY MINOR SHORTWAVE ENERGY, NO UPPER LEVEL JET, VERY UNIMPRESSIVE LOW LEVEL WIND FIELDS)...AND LESS THAN STELLAR FORCING WITH NO LOW LEVEL CONVERGENCE/UPPER LEVEL DIVERGENCE. UPPER LEVEL CLOUDS COUPLED WITH A SCATTERED TO BROKEN DECK AROUND 7K FEET SHOULD FILTER PLENTY OF SUNSHINE...THUS LIMITING OVERALL INSTABILITY. BUT STILL SHOULD BE ABLE TO REALIZE CAPES BETWEEN 1000-1500 J/KG...SO WOULDN`T EXPECT A LOT OF CONVECTIVE ACTIVITY ACROSS THIS AREA. NOW FARTHER NORTH...THE STORY IS MUCH DIFFERENT. BETTER MID TO UPPER SHORTWAVE ENERGY...GOOD UPPER LEVEL DIVERGENCE...AND DECENT LOW LEVEL CONVERGENCE ALL POINT TO A BETTER CHANCE OF SHOWERS AND THUNDERSTORMS FROM FLINT AND NORTH. WITH FAR MORE MOISTURE ACROSS THAT AREA (ESPECIALLY IN THE BOUNDARY LAYER), CAPES WILL HIT 2000 J/KG. VERY WEAK WIND FIELDS ARE NOT SUPPORTIVE OF ORGANIZED ACTIVITY...BUT WITH LOWERING FREEZING LEVELS...THERE DOES EXIST AN OUTSIDE CHANCE OF MARGINALLY SEVERE HAIL. PW`S AROUND 1.5 AND SLOW STORM MOVEMENT WILL LEAD TO HEAVY RAIN IN THUNDERSTORMS. BUT GIVEN THE LACK OF RUN TO RUN CONTINUITY AND THE FACT THAT THE NAM IS NOT NEARLY AS ROBUST AS THE GFS...SCATTERED SHOWERS AND THUNDERSTORMS LOOKS LIKE THE WAY TO GO AND THE PREVIOUS FORECAST HAS IT COVERED. DYNAMICS/MOISTURE WILL ONCE AGAIN BE ON THE RISE ON SUNDAY...STARTING JUST AFTER MIDNIGHT AS SURFACE LOW AND UPPER LEVEL DYNAMICS APPROACH FROM THE WEST. THE BIGGEST CHALLENGE FOR THE SUNDAY FORECAST REVOLVES AROUND THE EVOLUTION OF THE UPPER LOW MOVING NORTHEAST UP THE EAST COAST AND THE DEGREE OF CYCLOGENESIS THAT TAKES PLACE JUST OFF THE ATLANTIC SEABOARD. THE PREVIOUS RUN OF THE NAM WAS MUCH WEAKER AND WAY FARTHER WEST WITH THIS SYSTEM...GIVING CREDENCE TO MORE PHASING WITH THE UPPER LOW MOVING ACROSS THE GREAT LAKES ON SUNDAY. BUT THE LATEST RUN OF THE NAM HAS TRENDED IN THE DIRECTION OF THE GFS IN KEEPING THESE 2 SYSTEMS SEPARATE IDENTITIES. THE GFS...HOWEVER...IS STILL MUCH STRONGER WITH THE EAST COAST STORM AND A LITTLE FASTER AND FARTHER NORTH WITH THE SYSTEM THROUGH THE GREAT LAKES. THE STRONGER THE EAST COAST SYSTEM...THE MORE MOISTURE THAT WILL BE ROBBED FROM MAKING IT INTO THE GREAT LAKES. A COUPLE OF SURFACE TROUGHS ON SUNDAY AND SUNDAY EVENING WILL PROVIDE EXTRA FORCING FOR AN EXTENDED PERIOD OF SHOWERS AND THUNDERSTORMS. ONGOING CLOUDS/PRECIP AND WEAK COLD AIR ADVECTION WILL HOLD TEMPS AT 80 OR BELOW...THUS SOMEWHAT LIMITING THE INSTABILITY POTENTIAL...BUT FORECAST SOUNDINGS STILL SHOW BETWEEN 1000 - 1500 J/KG FROM FLINT AND SOUTH. FREEZING LEVELS WILL BE LOWERING...BUT WITH CONTINUED WEAK/UNIMPRESSIVE WIND FIELDS AND NOT TERRIBLY IMPRESSIVE DYNAMICS...THE SEVERE POTENTIAL LOOKS QUITE LOW...AND LIMITED TO HAIL. RAIN WILL BE THE BIG STORY...AS PW`S CONTINUE TO PERSIST NEAR 1.5 DURING THE DAY WITH THE NAM INDICATING OVER 1.6 PW`S DURING THE AFTERNOON. WEAK STEERING CURRENTS WILL SET THE STAGE FOR SLOW MOVING MULTICELLULAR CLUSTERS OF STORMS POTENTIALLY PRODUCING VERY HEAVY DOWNPOURS. THE AMOUNT OF RAIN RECEIVED WILL LARGELY DEPEND ON HOW MUCH MOISTURE THE EAST COAST SYSTEM TAKES AWAY...BUT REGARDLESS...SUNDAY WILL BE A WET AND STORMY DAY. A DRY SLOT AND FIRST SHOT OF COOLER AIR BEGINS TO FILTER IN BEGINNING LATE SUNDAY EVENING BEHIND SURFACE FRONT. MOISTURE/DYNAMICS WILL INCREASE ONCE AGAIN AHEAD OF MAIN COLD FRONT AND UPPER LEVEL TROUGH AXIS MONDAY AFTERNOON. STRANGELY ENOUGH...THE NAM AND GFS MOVE BACK INTO EXCELLENT AGREEMENT ON MONDAY REGARDING THE FRONTAL PASSAGE...WITH SCATTERED SHOWERS/THUNDERSTORMS POSSIBLE AHEAD OF THIS FRONT. A REINFORCING AND MUCH COLDER AIRMASS WILL MOVE IN OVERNIGHT AND KEEP US BELOW NORMAL FOR THE FIRST HALF OF THE WEEK BEFORE MODERATING LATER IN THE WEEK. MARINE... THE STORY CONTINUES WITH LIGHT WINDS FOR ALL MARINE AREAS THROUGH THE WEEKEND. A SLIGHT CHANCE OF SHOWERS AND THUNDERSTORMS WILL EXIST THIS EVENING WITH A CHANCE OF SHOWERS AND THUNDERSTORMS FOR THE REMAINDER OF THE WEEKEND. A COLD FRONT WILL EVENTUALLY SWEEP THROUGH THE REGION MONDAY AND MONDAY NIGHT BRINGING COOLER AIR. WIND AND WAVES ARE EXPECTED TO INCREASE BEHIND THIS FRONT AS THE WINDS INCREASE. && .DTX WATCHES/WARNINGS/ADVISORIES... MI...NONE. LAKE HURON...NONE. LAKE ST CLAIR...NONE. MI WATERS OF LAKE ERIE...NONE. && $$ AVIATION/UPDATE...CONSIDINE SHORT TERM...CB LONG TERM....SHULER YOU CAN OBTAIN YOUR LATEST NATIONAL WEATHER SERVICE FORECASTS ONLINE AT WWW.WEATHER.GOV/DETROIT (ALL LOWER CASE).

AREA FORECAST DISCUSSION
NWS SAN DIEGO CA
150 PM PDT MON JUN 4 2007 .SYNOPSIS... THE HIGH PRESSURE ALOFT THAT BROUGHT THE RECENT WARMING WILL DRIFT EAST TONIGHT. LOW PRESSURE TRACKING ACROSS CENTRAL CALIFORNIA WILL BRING COOLER WEATHER TUESDAY AND WEDNESDAY. THIS TROUGH WILL RAPIDLY DEEPEN MARINE LAYER FOR POSSIBLE DRIZZLE WEST OF THE MOUNTAINS. STRONG WINDS ARE LIKELY IN THE MOUNTAINS AND DESERTS TUESDAY AFTERNOON THROUGH WEDNESDAY. IT WILL SLOWLY WARM TOWARD THE END OF THE WEEK AS THE TROUGH WEAKENS. && .DISCUSSION...FOR EXTREME SOUTHWESTERN CALIFORNIA INCLUDING ORANGE... SAN DIEGO...WESTERN RIVERSIDE AND SOUTHWESTERN SAN BERNARDINO COUNTIES... THE MOST DRAMATIC WARMING TODAY OCCURRED IN THE 2200-3000 FOOT LAYER WHERE THE HIGH PRESSURE ALOFT FORCED OUT THE MARINE LAYER WITH WARM...DRY AIR ALOFT. THAT WAS IN THE VALLEYS AND FOOTHILLS WHERE TEMPERATURES WERE 5 TO 10 DEGREES HIGHER THAN YESTERDAY AND DEWPOINTS WERE 10 TO 15 DEGREES LOWER. MOST OTHER AREAS IN THE REGION WERE ALSO WARMER...BUT TO A LESSER DEGREE. TEMPS TAKE A DIVE TUESDAY AND WEDNESDAY AS A TROUGH OF LOW PRESSURE MOVES INLAND ACROSS CENTRAL CALIFORNIA. 850 MB TEMPS NEAR 24C TODAY FALL TO 16C TUESDAY AFTERNOON AND THEN TO 11C WEDNESDAY AFTERNOON. THE COMBINATION OF STRONGER ONSHORE GRADIENTS...THE GENESIS OF ANOTHER COASTAL EDDY AND A RAPIDLY DEEPENING MARINE LAYER WILL BRING BACK A MORE PERSISTENT DECK OF MARINE LAYER CLOUDS ALONG WITH AREAS OF DRIZZLE. BY WEDNESDAY MORNING THE DEPTH WILL BE NEAR 4000 FEET AND THAT WILL DELAY THE AFTERNOON CLEARING. HOWEVER...STRONG CAA WILL WIPE OUT THE INVERSION AND MOST AREAS WILL SEE SOME AFTERNOON SUN. WEDNESDAY LOOKS LIKE A CLASSIC REVERSE CLEARING SCENARIO WHERE THE COAST CLEARS EARLIER THAN THE VALLEYS. STRONG WINDS WILL PICK UP IN THE MTNS AND DESERTS TUESDAY AFTERNOON AND CONTINUE INTO WEDNESDAY. 700 MB WINDS ARE FORECAST TO INCREASE TO 40-50 KTS TUESDAY AFTERNOON AND POST FRONTAL SUBSIDENCE WILL SEND SOME OF THIS WIND ENERGY TOWARD THE SURFACE. IT WILL BE QUITE WINDY IN THE APPLE AND YUCCA VALLEYS THROUGH WEDNESDAY. MOUNTAIN WAVES AND ROTORS ARE LIKELY IN THE COACHELLA VALLEY AND THE SAN DIEGO COUNTY DESERTS WITH FREQUENT BOUTS OF BLOWING DUST AND SAND IN THE AFTERNOONS AND EVENINGS. WIND ADVISORIES WILL LIKELY BE NEEDED. THE LONG RANGE MODELS FORECAST A GRADUAL WEAKENING OF THE MEAN WEST COAST TROUGH THURSDAY TROUGH SUNDAY. 500 MB HEIGHTS SLOWLY RECOVER FOR INCREMENTAL WARMING EACH DAY NEXT. THE MARINE LAYER WILL CONTINUE ITS DAILY SEESAW ROUTINE...SURGING INLAND EACH EVENING AND RETREATING TOWARD THE COAST EACH AFTERNOON. && .AVIATION...041915Z LATE MORNING MDCRS SOUNDINGS INDICATE THE MARINE LAYER DEPTH HAD LOWERED TO AROUND 1700 FEET FROM THIS MORNING. MARINE LAYER SHOULD REMAIN BETWEEN 1700 AND 2000 FEET MSL THROUGH TUESDAY BEFORE DEEPENING TUESDAY AFTERNOON. STRATUS WITH BASES AROUND 1300 FEET MSL SHOULD PUSH BACK ONTO THE COAST DURING THE AFTERNOON BETWEEN 22Z AND 00Z AND THEN INLAND DURING THE EVENING REACHING THE INLAND VALLEY AREAS BY MIDNIGHT. CLEARING ON TUESDAY MIGHT BE A LITTLE SLOWER ESPECIALLY NEAR THE COAST DUE TO A COASTAL EDDY. ABOVE THE MARINE LAYER...VFR CONDITIONS THROUGH TUESDAY WITH CEILINGS ABOVE FL200 AND UNRESTRICTED VISIBILITIES. && .SGX WATCHES/WARNINGS/ADVISORIES... CA...NONE. PZ...NONE. && $$ PUBLIC...MOEDE AVIATION/MARINE...HORTON NWS ON THE WEB AT WEATHER.GOV/SANDIEGO