FXUS02 KWBC 121552
PMDEPD

EXTENDED FORECAST DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
1052 AM EST THU NOV 12 2015

VALID 12Z SUN NOV 15 2015 - 12Z THU NOV 19 2015

...HEAVY RAIN POSSIBLE IN THE MID AND LOWER MISSISSIPPI VALLEY
NEXT TUE-WED...

...OVERVIEW AND GUIDANCE PREFERENCES/UNCERTAINTY...

BUILDING UPPER RIDGING OVER THE EASTERN CONUS AND WESTERN ATLANTIC
WILL BE THE MAIN ROADBLOCK TO THE PATTERN NEXT WEEK. THIS WILL
SUPPORT SUCCESSIVE TROUGHING IN THE WESTERN/CENTRAL STATES THOUGH
THE DETAILS REMAIN FUZZY.

MODELS AND ENSEMBLES REMAIN IN GOOD AGREEMENT THROUGH ABOUT NEXT
TUE... DIGGING ENERGY THROUGH THE INTERIOR WEST AND FOUR CORNERS
REGION. OPERATIONAL MODELS SHOW A CLOSED LOW DEVELOPING NEAR NEW
MEXICO LATE MON INTO TUE AS THE TROUGH SPLITS N-S. THEREAFTER...
THE GFS/GEFS MEMBERS REMAIN ON THE SLOWER SIDE OF THE SPREAD WHILE
THE ECMWF/ECENS MEMBERS WERE QUICKER. THOUGH THIS IS OPPOSITE
THEIR TYPICAL BIASES... THE SPEED OF EJECTION WILL BE INFLUENCED
BY UPSTREAM ENERGY COMING INTO THE PAC NW MIDWEEK AS WELL AS THE
ORIENTATION OF UPPER RIDGING WEST OF CALIFORNIA. SPREAD IN THE
ENSEMBLE SYSTEMS HAS NOT DECREASED OFF THE PAC NW COAST NEXT
TUE-WED... AND HAS INCREASED IN THE ECMWF ENSEMBLES DESPITE
DECREASED LEAD TIME... WHICH LEADS TO LOW CONFIDENCE IN ANY
DETERMINISTIC SOLUTION. HOWEVER... MULTI-DAY MEANS POINT TO LOWER
HEIGHTS OVER CA/NV NEXT THU -- LIKE THE 00Z ECMWF ENSEMBLE MEAN OR
NAEFS MEAN -- RATHER THAN MODEST RIDGING -- LIKE THE 00Z/06Z GFS.
WITH SUCH DIFFERENCES IMPACTING THE DOWNSTREAM FLOW COUPLED WITH
THE LARGER SIGNAL... FELT COMPELLED TO SPLIT THE DIFFERENCE
BETWEEN THE ECMWF ENSEMBLE MEAN AND NAEFS MEAN FOR NEXT WED-THU
THAT SHOULD KEEP THE SOUTHERN PLAINS ENERGY PROGRESSIVE AND LIFT
IT NORTHWARD INTO THE LAKES AND SOUTHERN CANADA BY NEXT THU RATHER
THAN LEAVE IT BEHIND. THIS WOULD THEN ALLOW UPSTREAM ENERGY TO DIG
INTO THE WEST YET AGAIN.


...SENSIBLE WEATHER HIGHLIGHTS...

MAIN FRONTAL BOUNDARY WILL PROGRESS THROUGH THE WEST NEXT SUN-MON
WITH WIDESPREAD SHOWERS AND MOUNTAIN SNOWS. SOUTHERN CA INTO THE
DESERT SW REGION WILL MISS THIS SYSTEM AS IT SHOULD BE TOO FAR
INLAND. NEXT MON-TUE AS THE SOUTHERN ENERGY DEEPENS A NEW SURFACE
LOW WILL FORM AND DEVELOP IN THE SOUTHERN PLAINS. ENOUGH COLD AIR
SHOULD BE PRESENT FOR SNOW TO FLY ON THE NW SIDE OF THE DEVELOPING
SURFACE LOW. STRONG UPPER JET -- ABOUT 130KTS -- AND DIFLUENCE
ALOFT COUPLED WITH INCREASED MOISTURE FROM THE GULF SHOULD SUPPORT
A HEAVY RAIN AND SEVERE WEATHER THREAT MON INTO TUE. THE STORM
PREDICTION CENTER IS HIGHLIGHTING MONDAY WITH AN INCREASED THREAT
OF SEVERE WEATHER OVER EASTERN TEXAS. AS THE SYSTEM LIFTS
NORTHEASTWARD THE HEAVY RAIN WILL FOLLOW ALONG AND AHEAD OF ITS
PATH. THE POTENTIAL FOR SEVERAL INCHES OF RAIN IS HIGHEST FROM E
TX AND LA NORTHWARD TO THE OHIO VALLEY.


FRACASSO

$$