PDA

View Full Version : 4/6 Weather



Digger
04-07-2007, 08:31 AM
It is still unclear to me if the coupled ocean-atmosphere (and other processes) system is evolving toward La-Nina since May is a critical month.
The weather-climate situation remains very complicated meaning most (not all) signals are weak. Short course is the extended North Pacific jet of roughly 2 weeks ago contributed to an eastward shift of the most intense tropical convection in a period of about a week. This forcing has since weakened. The latter is a component of the slow westward drift of the tropical forcing from the South Pacific which started around mid-January.

As most ensembles are capturing, another extended North Pacific jet episode is highly probable starting this weekend leading to strong troughs that will first slam into the USA west coast. This situation is likely to weaken coastal upwelling along the California coast, at least in the short-term. These troughs are then likely to move into the Rockies and Plains. This means the April cold regime now affecting the Upper Mississippi Valley into the Northeast should moderate early next week. Going well into next week and possibly through week 3, much of the lower 48 states may be in for an exceptionally stormy regime, centered on the Rockies and Plains. In fact, understanding the seasonal cycle, events similar to the period of the last couple of weeks of December 2006 and the last half of February 2007 may be probable.
Ed Berry

UPPER LOW NOW MOVING INTO NORTHERN CALIFORNIA HAS LOST IT'S PUNCH AS IT WEAKENED AND IS MOVING MORE DUE EAST....LARGE SCALE EAST COAST UPPER LOW IS NOW PULLING EAST AND WILL OPEN THE DOOR TO THE WELL ADVERTISED WEDNESDAY SYSTEM.

THIS SYSTEM WILL BE MORE A OF TYPICAL WINTER STORM WITH WIND AND SNOW....LOOKS LIKE A ONE FOOT PLUS SYSTEM WEDNESDAY/WEDNESDAY NIGHT.....IN THE MEANTIME LOTS OF CLOUDS FOR THE EASTER BUNNY....SOME ISOLATED SHOWERS MUCH LIKE YESTERDAY.....NOT MUCH ELSE GOING ON UNTIL THE WINDS COME UP LATER TUESDAY NIGHT...

LONGER RANGE SHOWS YET ANOTHER SYSTEM BY NEXT WEEKS END.....MAKE YOUR PLANS FOR SOME APRIL POWDER NEXT WEEK AS WINTER BEGINS TO WIND DOWN......

H.SCHECKTER

THE PACIFIC NORTHWEST CONTINUES A WINTRY PATTERN FOR MOST OF NEXT WEEK

Digger
04-08-2007, 10:20 AM
NWS - RENO
MONDAY WILL BE BREEZY AS THE COLD AIR BEGINS TO FILTER IN. FLOW BEGINS TO AMPLIFY AGAIN TUESDAY NIGHT AS MORE POTENT SHORTWAVE APPROACHES THE WEST COAST WITH INCREASING CLOUDS AND WINDS ALOFT. PRECIP BAND PUSHES INTO THE SIERRA FROM TAHOE NORTHWARD TUESDAY NIGHT. THIS WOULD BRING THE ONSET OF THE WINDS TO LEESIDE LOCATIONS ALTHOUGH MODELS ARE NOT REALLY PICKING UP ON THE WIND JUST YET

WEDNESDAY THROUGH SATURDAY...
MODELS HAVE SPED UP TIMING OF PCPN WED IN WARM SECTOR OF UPPER TROUGH AND JET. JET DIGGING FURTHER E ON LATEST GFS RUN WITH LESS OVER WATER TRAJECTORY AND THUS LESS QPF THAN FCST BY EARLIER RUNS. STILL IMPRESSIVE 160 KT JET ON W SIDE OF THIS NEG TILT TROUGH AND COLD POOL OF MINUS 32 AT 500 MB AND MINUS 12 AT 700 MB WOULD IMPLY PERIOD OF HEAVY SNOW IN SIERRA LATE WED AND WED NGT BEFORE TURNING TO SNOW SHOWERS ON THURSDAY. HAVE MAINTAINED LIKELY POPS IN SIERRA ZONES WED AND WED NGT ALTHOUGH CONFIDENCE IN QPF LESS WITH MODELS TRENDING DOWN. SNOW LEVELS DROPPING RAPIDLY TO VALLEY FLOORS OF WRN NV WEDNESDAY NIGHT UNDER COLD POOL ALOFT. SNOW ACCUMULATIONS IN THE SIERRA COULD BE A FOOT OR MORE ABOVE 7000 FEET WITH SOME LIGHT ACCUMULATIONS ON VALLEY FLOORS OF WRN NV BY THURSDAY MORNING. HIGH PRESSURE REBUILDS OVER AREA ON FRIDAY FOR DRY AND STABLE CONDS.

MEDIUM RANGE MODELS SIMILAR BRINGING WX SYSTEMS INTO AREA WITH FREQUENCY OF ABOUT EVERY 3 DAYS WED AND NEXT ONE SATURDAY.
SATURDAY SYSTEM LOOKS SIMILAR TO WED SYSTEM BUT HAVE KEPT CHC POPS FOR THIS DAY SEVEN PERIOD