Buckets of rain today, but a dry weekend ahead

Raw from the NWS:

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE EUREKA CA
319 AM PST FRI DEC 30 2011

.SYNOPSIS…WET WEATHER WILL CONTINUE TODAY AS RAIN SPREADS EAST
AND SOUTH ACROSS THE REGION. DRY WEATHER WILL RETURN TONIGHT THROUGH
THE WEEKEND. VALLEY FOG CAN BE EXPECTED EACH NIGHT AND INTO THE
MORNING HOURS THIS WEEKEND.

&&

.DISCUSSION…PERSISTENT ONSHORE FLOW CONTINUES TO BRING ABUNDANT
MOISTURE INTO THE HUMBOLDT AND DEL NORTE COUNTIES. PRECIPITABLE
WATER IS CURRENTLY IN EXCESS OF ONE INCH AND THE MOISTURE PLUME
STRETCHES FAR BACK WEST INTO THE PACIFIC. AS OF 2 AM THE MOISTURE
PLUME CONTINUES TO BE FOCUSED INTO EXTREME SOUTHERN
OREGON…HOWEVER AS THE COLD FRONT AND UPPER LEVEL TROUGH MOVE
EAST TOWARD THE REGION THE FOCUS WILL SHIFT SOUTH WITH TIME. BY
EARLY MORNING THE PRIMARY FOCUS WILL BE OVER OUR REGION WITH
RAINFALL RATES IN SOME LOCATIONS OF DEL NORTE AND NORTHERN
HUMBOLDT COUNTY EXCEEDING 0.30 INCH PER HOUR. TOTAL
RAINFALL…INCLUDING RAINFALL SINCE MIDNIGHT…SHOULD RANGE FROM
2-3 INCHES IN DEL NORTE COUNTY TO AROUND AN INCH IN SOUTHERN
HUMBOLDT COUNTY…AND A QUARTER INCH IN SOUTHERN MENDOCINO COUNTY
TODAY. AS THE UPPER LEVEL TROUGH…CURRENTLY CENTERED NEAR 42N
139W…MOVES EAST TOWARD NORTHERN CALIFORNIA AND OREGON TODAY IT
WILL PUSH THE COLD FRONT THROUGH THE CWA BEGINNING LATE IN THE
MORNING THROUGH THE EARLY AFTERNOON. AT THE SAME TIME SNOW LEVELS
WILL DROP FROM AROUND 6-7K FT CURRENTLY TO NEAR 3-4K FT BY TONIGHT
ACROSS THE NORTHERN HALF OF THE CWA. POST FRONTAL SHOWERS WILL
LINGER THROUGH THE AFTERNOON INTO THE EVENING AND WILL LIKELY
ALLOW FOR SOME SNOWFALL ABOVE ELEVATIONS NEAR 4K FT WHERE A FEW
INCHES WILL LIKELY FALL…ESPECIALLY ACROSS THE HIGHEST TERRAIN OF
DEL NORTE COUNTY. BY LATE THIS EVENING MOST SHOWER ACTIVITY WILL
COME TO AN END AS UPPER LEVEL RIDGING BUILDS BACK OVER THE WEST
COAST. TEMPERATURES TONIGHT WILL BE SIGNIFICANTLY LOWER THEN THE
PAST FEW NIGHTS AS DRIER…COOLER AIR FILTERS IN OVER THE REGION
BEHIND THE COLD FRONT. TEMPERATURES WILL FALL WELL BELOW FREEZING
INLAND WITH LOWER TO MIDDLE 30S EXPECTED NEAR THE COAST. FOG WILL
ALSO BE OF CONCERN IN VALLEY LOCATIONS WITH CONSIDERABLE LOW LEVEL
MOISTURE FROM THE RECENT RAINS.

AS THIS RIDGE BUILDS A WARM FRONT WILL DEVELOP AHEAD OF THE NEXT
APPROACHING SYSTEM WELL OFF THE COAST. MODELS ARE IN GREAT AGREEMENT
NOW WITH THE GREATEST UPPER LEVEL DYNAMICS ASSOCIATED WITH THIS
FRONT REMAINING OFF THE COAST AND LEAVING THE CWA DRY. 850 MB TEMPS
WILL STEADILY RISE SATURDAY AND SUNDAY AS SOUTHERLY FLOW DEVELOPS
ACROSS THE REGION. TEMPERATURES ON SUNDAY WILL LIKELY BE ABOVE
NORMAL WITH LOWER TO MID 60S INLAND AND UPPER 50S TO NEAR 60 NEAR
THE COAST. BY SUNDAY NIGHT MOISTURE WILL INCREASE ALONG THE COAST
AND STRATUS MAY BECOME AN ISSUE OVER THE COAST WATERS AND COASTAL
LOCATIONS. ADDITIONALLY VALLEY FOG WILL CONTINUE TO DEVELOP SATURDAY
AND SUNDAY NIGHTS.

BY MONDAY THE NEXT TROUGH WILL ADVANCE TOWARD THE COAST. MODELS ARE
IN BETTER AGREEMENT OF SOME PRECIP REACHING THE COAST AS THE UPPER
LEVEL VORT IS NOW FORECAST TO MOVE MUCH FURTHER SOUTH THEN WAS
PREDICTED A COUPLE OF DAYS AGO. STILL MOISTURE WILL BE LIMITED WITH
THIS SYSTEM AS ONLY A NARROW PLUME OF MOISTURE IS FORECAST TO MOVE
OVER THE REGION. THUS PRECIP WILL LIKELY REMAIN WELL BELOW A HALF
INCH IN MOST LOCATIONS. THE UPPER LEVEL VORT WILL THEN EJECT
NORTHEAST OF THE REGION MONDAY NIGHT WITH RIDGING BUILDING BACK IN
ITS WAKE. SOUTHERLY FLOW WILL PERSIST BEHIND THIS SYSTEM WITH GOOD
BOUNDARY LAYER MOISTURE ALONG THE COAST. THUS STRATUS MAY
REMAIN…BUT AT THIS TIME CONFIDENCE IS TOO LOW TO INCLUDE ANY
COASTAL FOG MENTION. VALLEY FOG WILL STILL BE OF CONCERN OVERNIGHT
INTO THE MORNING HOURS.

MODELS ARE THEN IN AGREEMENT WITH RIDGING OVER THE REGION FOR
TUESDAY BEFORE ANOTHER TROUGH ADVANCES TOWARD THE COAST WEDNESDAY
INTO WEDNESDAY NIGHT. AMAZINGLY THE GFS…ECMWF…AND GEM MODELS ALL
ARE INDICATING THE NEXT FRONTAL PASSAGE IN THE SAME 12 HR PERIOD
WEDNESDAY NIGHT. THUS POPS HAVE BEEN INCREASED ABOVE CLIMO WEDNESDAY
NIGHT INTO THURSDAY AND THEN REMAIN NEAR CLIMO THURSDAY NIGHT AS
POST FRONTAL SHOWERS WILL LIKELY LINGER. RPA

Advertisements

Leave a comment

Filed under Uncategorized

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s