Forecast Discussions mentioning "ACARS", "MDCRS", or "AIRCRAFT" received at FSL on 03/10/02

.SYNOPSIS...A WEAK TROUGH OF LOW PRESSURE WILL MOVE BY TO THE NORTH ON SUNDAY...BUT THAT WILL ONLY BRING SOME HIGH CLOUDS. THE JET STREAM WILL REMAIN WELL TO THE NORTH...AND ONSHORE FLOW WILL REMAIN WEAK THROUGH TUESDAY AND KEEP THE WEATHER FAIR AND MILD...THEN LOW PRESSURE ALOFT WILL DEVELOP TO OUR NORTH AND BRING COOLING AND MORE CLOUDINESS IN THE SECOND HALF OF THE WEEK.

.DISCUSSION...IT IS A QUIET NIGHT TONIGHT AS SURFACE PRESSURE GRADIENTS ARE ALMOST AS WEAK AS THEY GET...AND ACARS SOUNDINGS SHOW BASICALLY NO MARINE INVERSION. DEW POINTS ARE HIGH ENOUGH NEAR THE COAST THAT A SMALL AMOUNT OF FOG IS POSSIBLE...AND THAT IS COVERED IN THE ZONES...AT LEAST FOR COASTAL SAN DIEGO COUNTY.

THE LOW PRESSURE TROUGH IS BECOMING WEAK ENOUGH THAT THE HIGH CLOUDS WILL BE ABOUT THE ONLY AFFECT. IN FACT...850 MB TEMPS INCREASE...SO MTN/DESERT TEMPS SHOULD INCREASE A FEW DEGREES. I WILL RECOMMEND THE MIDNIGHT SHIFT CONSIDER ADDING A FEW DEGREES TO A FEW ZONES FOR SUNDAY...OTHERWISE THE CURRENT FORECAST LOOKS GOOD. NO ZONE UPDATE WILL BE ISSUED.

BROAD LOW PRESSURE DEVELOPS STARTING AROUND WED OVER THE PAC NW/N CAL...BUT WHETHER OR NOT PRECIP CAN SHIFT SOUTH INTO OUR AREA WILL DEPEND ON HOW FAR S THE JET STREAM CAN DIG. THE MRF WAS SOMEWHAT MARGINAL FOR PRECIP...BUT THE NEW ECM LOOKS BETTER WITH ITS LOWER HEIGHTS.

.SAN...NONE.

MAXWELL



SHORT TERM DISCUSSION: FIRST ISSUE...HIGH WIND POTENTIAL IN THE MEDICINE BOW AND FRONT RANGES NEXT SVRL HRS. SEE CONDITIONS QUICKLY COMING TOGETHER FOR ANOTHER PERIOD OF STRONG AND GUSTY WLY WINDS. RADAR WIND SIGNATURE ALREADY IN PLACE JUST EAST OF THE DVD TOGETHER WITH FOEHN GAP/MTN WAVE DRY SLOT ON H2O WATER SATL LOOP. LATEST ACARS SOUNDING OVR DEN HAD 50 KT WLY WINDS FM 500 MBS UP THRU 350 MBS...A FAVORABLE WIND SHEAR PROFILE FOR MTN WAVE AMPLIFICATION. 06Z/MM5 CROSS SECTION ALSO SHOWED A WELL DVLPD HIGH AMPLITUDE MTN WAVE OVR THE FRONT RANGE THRU 16Z THIS MORNING AND A PEAK CROSS BARRIER WIND OF 60KT NEAR 680 MBS AT 14Z. 600-500MB LAPSE RATES OVR FNT RANGE ALSO AT THEIR LOWEST VALUES AT ABOUT SAME TIME ACCORDING TO BOTH MM5 AND MESOETA. FURTHERMORE MM5 SHOWED WIND MAXIMA WORKING DOWN EAST FACE OF FRONT RANGE DURING MORNING HRS. HWVR IT APRS STRONGEST WINDS NEVER DROP BELOW 8500 FT OR SO. EVEN THOUGH ALL THIS POINTS TO A HIGH WIND EVENT...BLV SUSTAINED WINDS OF GREATER THAN 50 MPH AND GUSTS OF 70 MPH OR MORE WILL NOT BECOME WIDESPREAD. STILL SHOULD SEE WINDS OCCASIONALLY EXCEEDING THESE VALUES PARTICULARLY AT ELEVATIONS ABV 10 THOUSAND FT THROUGH MIDDAY.

NOW TO THE SECOND ISSUE. HIGH WIND THREAT ACTUALLY LOOKS BETTER LATE TONIGHT WITH STG NW-ORIENTED JET FLOW PASSING OVR NRN MTNS. ALSO SEE SNOWFALL RETURNING TO THE MTNS AND HIGH VLYS OVERNIGHT. ETA AND AVN SHOW MOISTURE DEEPENING RAPIDLY AFT 00Z/MON. PLUGGING INTO THE OROGRAPHIC SNOW MODEL A H7 260 DEG 25KT WIND...H7 -8C TEMP AND A H7-H5 LAPSE RATE OF 7.5C/KM CAME UP WITH 2-5 INCH SNOW AMTS IN THE GORE AND PARK RNGS (ZN 31) AND 1-3 INCH AMTS IN N-CNTRL MTN ZNS 33 AND 34 OVRNGT. ITS A QUICK SHOT OF PCPN AS LEFT EXIT QUAD OF 80-110 KT 500-300MB JET PASSES OVR AREA AROUND 06Z/MON...ABOUT SAME TIME LOW/MID LVL COLD ADVECTION AT ITS STRONGEST WITH PASSAGE OF SHRT WV TROF. HWVR WOULD BE NICE TO SEE MORE MOISTURE...THEREFORE THE LOW SNOW AMTS. BETWEEN ALL THIS SEE UNSEASONABLY WARM TEMPS ACROSS THE CWFA TODAY WITH AFTN READINGS RANGING FM MID 50S TO LOWER 60S ON THE PLAINS AND UPR 30S AND 40S IN THE HIGH COUNTRY. FORMATION OF MTN WAVE CLOUDS LATER THIS MORNING AND A WK DENVER CYCLONE MIGHT KEEP TEMPS FM REACHING TO 60 DEG MARK WITHIN THE URBAN CORRIDOR AS MOS GUIDANCE AND H7 TEMP WOULD HAVE US BELIEVE. BAKER LONG TERM DISCUSSION: LAST 2 MODEL RUNS HAVE BEEN FASTER AND LESS AMPLIFIED WITH THE TROF PASSAGE SO BY THE TIME WE GET TO MONDAY MORNING LOOKS LIKE A BORA PATTERN WILL ALREADY BE IN PLACE. SOME QUESTION AS TO ISSUE A HIGH WIND WATCH WITH 700 MB WINDS CLOSE TO 50 KNOTS AND PRETTY HEALTHY SUBSIDENCE BEHIND SHORT WAVE PASSAGE. HOWEVER...SURFACE PRESSURE GRADIENT IS NOT THAT STRONG AND FORECAST SANGSTER BACKS THIS UP WITH VALUES QUITE A BIT BELOW HIGH WIND WATCH/WARNING CRITERIA. WILL THEREFORE HOLD OFF ON A WATCH FOR NOW. EVEN WITH SOME COLD ADVECTION...RAISED TEMPERATURES A FEW DEGREES WITH DOWNSLOPE FLOW IN PLACE AND TEMPS WARMING DRY ADIABATICALLY PAST 700 MB.

LIGHT SNOW IN THE MOUNTAINS WILL BE DECREASING DURING THE DAY MONDAY AS SUBSIDENCE...DRYING...AND STABILIZATION OCCUR. ADDITIONAL ACCUMULATIONS SHOULD BE MINIMAL. WILL ADD SOME SCATTERED LIGHT SNOW SHOWERS TO MONDAY NIGHT AND TUESDAY PERIODS WITH WESTERLY FLOW ALOFT BRINGING IN PERIODS OF MID LEVEL MOISTURE WHICH SHOULD BE ENOUGH TO GENERATE A BIT OF SNOW.

FARTHER OUT IN TIME...MODELS CONTINUE TO INDICATE LONG WAVE TROF DIGGING OVER THE WESTERN U.S. WITH A LEAD SHORT WAVE EJECTING OUT SOMETIME THURSDAY AND/OR FRIDAY. GOING FORECAST FOR CHANCE OF SNOW AND COLDER TEMPS BOTH DAYS LOOKS GOOD.

BARJENBRUCH

.DEN...NONE.



SHORT TERM DISCUSSION: FIRST ISSUE...HIGH WIND POTENTIAL IN THE MEDICINE BOW AND FRONT RANGES NEXT SVRL HRS. SEE CONDITIONS QUICKLY COMING TOGETHER FOR ANOTHER PERIOD OF STRONG AND GUSTY WLY WINDS. RADAR WIND SIGNATURE ALREADY IN PLACE JUST EAST OF THE DVD TOGETHER WITH FOEHN GAP/MTN WAVE DRY SLOT ON H2O WATER SATL LOOP. LATEST ACARS SOUNDING OVR DEN HAD 50 KT WLY WINDS FM 500 MBS UP THRU 350 MBS...A FAVORABLE WIND SHEAR PROFILE FOR MTN WAVE AMPLIFICATION. 06Z/MM5 CROSS SECTION ALSO SHOWED A WELL DVLPD HIGH AMPLITUDE MTN WAVE OVR THE FRONT RANGE THRU 16Z THIS MORNING AND A PEAK CROSS BARRIER WIND OF 60KT NEAR 680 MBS AT 14Z. 600-500MB LAPSE RATES OVR FNT RANGE ALSO AT THEIR LOWEST VALUES AT ABOUT SAME TIME ACCORDING TO BOTH MM5 AND MESOETA. FURTHERMORE MM5 SHOWED WIND MAXIMA WORKING DOWN EAST FACE OF FRONT RANGE DURING MORNING HRS. HWVR IT APRS STRONGEST WINDS NEVER DROP BELOW 8500 FT OR SO. EVEN THOUGH ALL THIS POINTS TO A HIGH WIND EVENT...BLV SUSTAINED WINDS OF GREATER THAN 50 MPH AND GUSTS OF 70 MPH OR MORE WILL NOT BECOME WIDESPREAD. STILL SHOULD SEE WINDS OCCASIONALLY EXCEEDING THESE VALUES PARTICULARLY AT ELEVATIONS ABV 10 THOUSAND FT THROUGH MIDDAY.

NOW TO THE SECOND ISSUE. HIGH WIND THREAT ACTUALLY LOOKS BETTER LATE TONIGHT WITH STG NW-ORIENTED JET FLOW PASSING OVR NRN MTNS. ALSO SEE SNOWFALL RETURNING TO THE MTNS AND HIGH VLYS OVERNIGHT. ETA AND AVN SHOW MOISTURE DEEPENING RAPIDLY AFT 00Z/MON. PLUGGING INTO THE OROGRAPHIC SNOW MODEL A H7 260 DEG 25KT WIND...H7 -8C TEMP AND A H7-H5 LAPSE RATE OF 7.5C/KM CAME UP WITH 2-5 INCH SNOW AMTS IN THE GORE AND PARK RNGS (ZN 31) AND 1-3 INCH AMTS IN N-CNTRL MTN ZNS 33 AND 34 OVRNGT. ITS A QUICK SHOT OF PCPN AS LEFT EXIT QUAD OF 80-110 KT 500-300MB JET PASSES OVR AREA AROUND 06Z/MON...ABOUT SAME TIME LOW/MID LVL COLD ADVECTION AT ITS STRONGEST WITH PASSAGE OF SHRT WV TROF. HWVR WOULD BE NICE TO SEE MORE MOISTURE...THEREFORE THE LOW SNOW AMTS. BETWEEN ALL THIS SEE UNSEASONABLY WARM TEMPS ACROSS THE CWFA TODAY WITH AFTN READINGS RANGING FM MID 50S TO LOWER 60S ON THE PLAINS AND UPR 30S AND 40S IN THE HIGH COUNTRY. FORMATION OF MTN WAVE CLOUDS LATER THIS MORNING AND A WK DENVER CYCLONE MIGHT KEEP TEMPS FM REACHING TO 60 DEG MARK WITHIN THE URBAN CORRIDOR AS MOS GUIDANCE AND H7 TEMP WOULD HAVE US BELIEVE. BAKER LONG TERM DISCUSSION: LAST 2 MODEL RUNS HAVE BEEN FASTER AND LESS AMPLIFIED WITH THE TROF PASSAGE SO BY THE TIME WE GET TO MONDAY MORNING LOOKS LIKE A BORA PATTERN WILL ALREADY BE IN PLACE. SOME QUESTION AS TO ISSUE A HIGH WIND WATCH WITH 700 MB WINDS CLOSE TO 50 KNOTS AND PRETTY HEALTHY SUBSIDENCE BEHIND SHORT WAVE PASSAGE. HOWEVER...SURFACE PRESSURE GRADIENT IS NOT THAT STRONG AND FORECAST SANGSTER BACKS THIS UP WITH VALUES QUITE A BIT BELOW HIGH WIND WATCH/WARNING CRITERIA. WILL THEREFORE HOLD OFF ON A WATCH FOR NOW. EVEN WITH SOME COLD ADVECTION...RAISED TEMPERATURES A FEW DEGREES WITH DOWNSLOPE FLOW IN PLACE AND TEMPS WARMING DRY ADIABATICALLY PAST 700 MB.

LIGHT SNOW IN THE MOUNTAINS WILL BE DECREASING DURING THE DAY MONDAY AS SUBSIDENCE...DRYING...AND STABILIZATION OCCUR. ADDITIONAL ACCUMULATIONS SHOULD BE MINIMAL. WILL ADD SOME SCATTERED LIGHT SNOW SHOWERS TO MONDAY NIGHT AND TUESDAY PERIODS WITH WESTERLY FLOW ALOFT BRINGING IN PERIODS OF MID LEVEL MOISTURE WHICH SHOULD BE ENOUGH TO GENERATE A BIT OF SNOW.

FARTHER OUT IN TIME...MODELS CONTINUE TO INDICATE LONG WAVE TROF DIGGING OVER THE WESTERN U.S. WITH A LEAD SHORT WAVE EJECTING OUT SOMETIME THURSDAY AND/OR FRIDAY. GOING FORECAST FOR CHANCE OF SNOW AND COLDER TEMPS BOTH DAYS LOOKS GOOD.

.DEN...NONE.



.SYNOPSIS...A WEAK TROUGH MOVING BY TO THE NORTH TODAY WILL BRING A SLIGHT INCREASE IN CLOUDS AND WIND TO SOUTHWEST CALIFORNIA. HIGH PRESSURE WILL REBUILD MONDAY THEN WEAKEN TUESDAY. A STRONGER TROUGH WILL MOVE INLAND LATE WEDNESDAY AND THURSDAY. THE SECOND HALF OF THE WEEK IS EXPECTED TO BE 15 DEGREES COOLER.

.DISCUSSION...THOUGH PRESSURE GRADIENTS STILL QUITE WEAK...VAD WINDS SINCE LATE SATURDAY EVENING HAVE BEEN SOUTHEAST 20-30 KT BETWEEN 4000-10000 FT MSL. PROBABLY COMING FROM MIGRATING BIRDS...SINCE CORRESPONDING WINDS FROM RAWS/ACARS/RAOBS ARE GENERALLY SW-E LESS THAN 15 KTS. FOG/LOW CLOUDS A NO SHOW SO FAR...STILL DEBATING WHETHER TO GO MOSTLY SUNNY WITH SOME HIGH CLOUDS FOR TODAY OR PARTLY CLOUDY TO COVER THIS AND POSSIBILITY OF MID/LOW CLOUDS INCREASING DURING LATE AFTERNOON AS THE TROUGH PUSHES MOVES INLAND TO THE NORTH. CONSENSUS IS AVN MODEL BEST INITIALIZED OF MODELS. IT SHOWS STRONGER WINDS ON BACKSIDE OF THE TROUGH WHICH SUPPORTS FURTHER DIGGING/STRONGER TROUGH. HOWEVER ALL MODELS BY 11/00Z HAVE MOVED TROUGH INLAND TO THE GREAT BASIN WITH TRAILING AXIS OVER SW CALIFORNIA THROUGH 20N 130W. FLAT UPPER DIRTY RIDGE BUILDS ON MONDAY AND ERODES ON TUESDAY. SURFACE PRESSURE GRADIENTS INCREASING MONDAY NIGHT/TUESDAY ALONG CENTRAL CA COAST AND MESOETA MODEL DEVELOPS EDDY CIRCULATION OVER SRN CA BIGHT. WILL BREAK UP CURRENT BROAD BRUSH FORECAST TO SHOW SKY COVER/TEMP CHANGES RESULTING FROM THIS SCENARIO. 500 MB HEIGHTS CONTINUE TO FALL WEDNESDAY/THURSDAY AS NEXT AND STRONGER TROUGH MOVES INLAND. 850-700 MB WINDS FORECAST W-SW 25-40KTS WITH 1000-500 MB THICKNESSES DROPPING 120-150 METERS. LOWERED TEMPERATURES TO SHOW A 5 DEGREE DROP ON WEDNESDAY AND A 10 DEGREE DROP ON THURSDAY AND CHANGED BREEZY TO WINDY FOR DESERTS/MTNS. PROBABILITY OF PRECIPITATION THREAT STILL BELOW 20 PERCENT SO NO MENTION YET FOR THESE TIME PERIODS. COOL NW FLOW ALOFT CONTINUES FRIDAY AND SATURDAY AS HIGH AMPLITUDE RIDGE BUILDS ALONG 145W LONGITUDE. SPAGHETTI ENSEMBLE OF MODEL RUNS SHOW A FAIR CONSISTENCY WITH MEAN POSITION OF THIS BUILDING RIDGE. FOR DAYS 8 THROUGH 10 MRF SHOWS TROUGH CARVING OUT A DEEP COLD LOW OVER GREAT BASIN. NOT UNREALISTIC FOR THIS TIME OF YEAR.

.SAN...NONE.

BALFOUR