STORM2K

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN DIEGO
330 AM PST SUN MAR 21 2004

.SYNOPSIS...WEAK HIGH PRESSURE OVER SOUTHERN CALIFORNIA WILL CONTINUE THE FAIR...DRY...WARM WEATHER TODAY. A LARGE UPPER LEVEL LOW PRESSURE SYSTEM OVER THE EASTERN PACIFIC WILL MOVE SLOWLY TOWARD THE WEST COAST THIS WEEK. THIS WILL BRING A GRADUAL COOLING TREND TO SOUTHWEST CALIFORNIA ALONG WITH LOCALLY GUSTY AFTERNOON AND EVENING WINDS IN THE MOUNTAINS AND DESERTS AND AND A DEEPER MARINE LAYER. THIS LOW PRESSURE SYSTEM MAY MOVE ONSHORE BY THE WEEKEND BRINGING A CHANCE OF PRECIPITATION TO SOUTHWEST CALIFORNIA.

.DISCUSSION...FOR EXTREME SOUTHWESTERN CALIFORNIA INCLUDING ORANGE...SAN DIEGO...WESTERN RIVERSIDE AND SOUTHWESTERN SAN BERNARDINO COUNTIES.

.SHORT TERM...ACARS SOUNDINGS SHOW THE DEPTH OF THE MARINE LYR AROUND 2000 FT...NOT TOO MUCH DIFFERENT THAN 24 HOURS AGO. HOWEVER...UNLIKE 24 HOURS AGO...WINDS JUST ABV THE INVERSION ARE FM THE WEST RATHER THAN THE EAST. DOWNSLOPE WARMING THAT OCCURRED SAT AFTERNOON IN THE INLAND VLYS SHOULD BE ABSENT TODAY. HOWEVER...COASTAL FOOTHILL LOCATIONS NR THE TOP OF THE MARINE INVERSION SHOULD BE NRLY AS WARM AS SATURDAY. MESOETA CONTINUES TO ADVERTISE A SLIGHT DECR IN MARINE LYR DEPTH FOR TONIGHT INTO MON MORNING. THIS COULD BRING MORE DENSE FOG TO THE MESAS AND LWR COASTAL VLYS LATE TONIGHT INTO MON MORNING.

FOR MONDAY NIGHT THRU THU...LARGE CLOSED UPR LOW OVR THE ERN PACIFIC WL MOVE SLOWLY EASTWARD TOWARD THE WEST COAST. THIS WILL BRING GRADUAL COOLING TO INLAND AREAS WITH LCLLY GUSTY AFTERNOON AND EVENING WINDS IN THE MTNS AND DESERTS. WELL DEFINED COASTAL EDDY AS SHOWN BY THE MESOETA WL BRING SOME DEEPENING OF THE MARINE LYR MONDAY NIGHT INTO TUESDAY AND GREATER DEEPENING TUESDAY NIGHT INTO WEDNESDAY WITH SLOW/NO CLRG FOR SOME AREAS WEDNESDAY AFTERNOON.

.LONG TERM...DEVELOPING THIRD MJO EVENT OF THIS WINTER COULD BRING A RETURN OF PRECIPITATION BY THE WEEKEND. ECMWF/GFS ARE NOW SIMILAR IN MOVG THE ERN PAC CLOSED LOW ONSHORE INTO CA FRI NIGHT AND SATURDAY WITH THE UPR LOW MOVG EAST LATE SUNDAY AND SUNDAY NIGHT. THIS COULD BRING A RETURN OF RAIN TO SW CA LATE FRI AFTERNOON OR FRIDAY NIGHT WITH SHOWERS LINGERING INTO SUNDAY.

GRAPHICS OF THE LATEST MJO INDICES ARE AVBL FM THE CPC AT...

HTTP://WWW.CPC.NCEP.NOAA.GOV/PRODUCTS/P ... INDEX.HTML

-------------------------------------------------------------------------------------

Another MJO could mean what? More heavy rain?

Thanks for the info Joshua Interesting

Impressive!: http://www.atmos.washington.edu/images/ ... 212300.gif

That system will affect the Southwest in the coming days ... that very wound up system in that satellite picture is producing hurricane force winds and has a minimum central pressure of 966 mb ...

http://www.opc.ncep.noaa.gov/shtml/P_sfcbw.gif

ECMWF by Day 7 has the NE Pacific low opening up with a new low replacing that moving into Alaska. The current low moves east and then southeast hugging the West Coast before cutting off at the 500mb levels in the Desert Southwest ...

That can't be good :o .

events associated with an active MJO surge tend to lose their punch as they shift southward-additionally, by this time of the year the ULLs that track infrom CA tend to do so further north which means that the dynamics needed to deepen the Marine Layer sufficiently to get moisture over the mountains of SoCA and Baja are usually lacking thus we usually end up with clouds and wind but little rain in AZ from them except up north and closer to the center of action. For the record, 966mb Lows with hurricane force winds are no strangers to the North Pacific-particularly around the Aleutians. Now if it were 946mb I'd be impressed.

Steve.