Prognostic Meteorological Discussion
Issued by NWS

Home | Current Version | Previous Version | Text Only | Print | Product List | Glossary On
Versions: 1 2 3 4
000
FXUS02 KWBC 191519
PMDEPD

EXTENDED FORECAST DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
1118 AM EDT SUN APR 19 2015

VALID 12Z WED APR 22 2015 - 12Z SUN APR 26 2015

...OVERVIEW AND GUIDANCE PREFERENCES...

UPPER RIDGING CURRENTLY OVER BRITISH COLUMBIA WILL GRAVITATE
TOWARD THE CANADIAN ARCHIPELAGO THIS WEEK... WHICH FAVORS A BROAD
AND DISJOINTED OMEGA PATTERN ACROSS NORTH AMERICA. THE EASTERN
COMPONENT... A CLOSED LOW DRIFTING THROUGH SOUTHERN/EASTERN
CANADA... SHOWS THE BEST CONSENSUS WITH ITS LEAD SFC FRONT WELL
OFFSHORE ON WEDNESDAY WHILE A TRAILING SHORTWAVE WILL FORM ANOTHER
COLD FRONT TO PUSH THROUGH THE NORTHEAST ON THURSDAY. THE WESTERN
COMPONENT WILL BE LESS COHERENT AS IT LIES IN THE SPLIT FLOW OF
THE NORTHEAST PACIFIC. THIS WILL SEND SHORTWAVE IMPULSES THROUGH
CANADA AS WELL AS THROUGH THE SW STATES BUT THE MODELS/ENSEMBLES
HAVE HAD A TOUGH TIME DETERMINING THE DETAILS. HAVE USED THE ECMWF
ENSEMBLE MEAN AS THE BEST COMMON GROUND AS IT TYPICALLY PERFORMS
BETTER THAN THE GEFS IN BLOCKY/QUASI-AMPLIFIED FLOW. ITS
DETERMINISTIC COUNTERPART OFFERS USABLE DETAILS THROUGH ABOUT
FRI/SAT.


...SENSIBLE WEATHER HIGHLIGHTS...

ACTIVE AND AT TIMES `CHILLY` APRIL WEATHER PATTERN FOR THE GREAT
LAKES AND NORTHEAST WILL FOLLOW THE SLOWLY-MOVING CLOSED LOW
ACROSS SOUTHEASTERN CANADA. THIS FAVORS BELOW AVG TEMPERATURES
WITH SCATTERED RAIN/SNOW SHOWERS BUT GENERALLY DRIER AND SUNNIER
EAST OF THE APPALACHIANS IN THE MID-ATLANTIC.

IN THE WEST... AN ACTIVE SPRING WEATHER PATTERN COMES TO THE GREAT
BASIN... SIERRA... CENTRAL AND SOUTHERN CALIFORNIA... AND
DOWNSTREAM ACROSS THE COLORADO RIVER BASIN AND SOUTHERN ROCKIES
WITH A COUPLE UPPER-LEVEL TROUGHS DIGGING SOUTHEASTWARD THROUGH
THE DESERTS AND FOUR CORNERS REGION. MAX TEMPS WILL BE BELOW AVG
MOST OF THE PERIOD THANKS TO ABUNDANT CLOUDINESS AND LOWER HEIGHTS.

PRECIPITATION FOCUS EAST OF THE CONTINENTAL DIVIDE WILL BE
ALONG/BENEATH THE WEST-SOUTHWESTERLY ORIENTED JET STREAM AXIS AND
ALONG A NORTHERN STREAM STATIONARY BOUNDARY AS WELL AS THE
PROGRESSIVE SOUTHERN STREAM SHORTWAVE FRI INTO NEXT WEEKEND...
NAMELY... THE SOUTHERN PLAINS INTO THE SOUTHEAST... WHERE
TEMPERATURES STAND THE BEST CHANCE OF BEING ABOVE AVERAGE.


FRACASSO/VOJTESAK

$$





USA.gov is the U.S. government's official web portal to all federal, state and local government web resources and services.