Prognostic Meteorological Discussion
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FXUS02 KWBC 271551
PMDEPD

EXTENDED FORECAST DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
1151 AM EDT FRI MAY 27 2016

VALID 12Z MON MAY 30 2016 - 12Z FRI JUN 03 2016

TODAY`S NATIONAL FORECAST UTILIZED A BLEND OF THE 27/00Z
DETERMINISTIC ECMWF AND ECENS/NAEFS UNTIL 31/12Z (MID-POINT DAY
4)---THEN SHIFTED AWAY FROM A DETERMINISTIC SOLUTION...USING A
60/40 NAEFS/ECENS BLEND BY 1/12Z (MID-POINT DAY 5). IN SHORT---TO
SLOWDOWN THE WEST-TO-EAST PROGRESSION OF PACIFIC SYSTEMS ACROSS
THE NORTHERN TIER STATES.

THE 27/00Z GUIDANCE...PARTICULARLY THE ECENS AND ECMWF---WERE MUCH
FASTER AND LESS AMPLIFIED SOLUTIONS ALONG THE US/CANADA BORDER AND
WESTWARD TO 135W LONGITUDE AT DAY 5 (1/12Z) AND BEYOND. THE
DIFFERENCES TRANSLATED TO A FLATTER UPSTREAM TROUGH OFF THE
WASHINGTON COAST ...AND A FASTER FRONTAL PROGRESSION ACROSS THE
MIDWEST. AT 500 MBS...THE DETERMINISTIC ECMWF IS NEARLY 10 DEGREES
OF LONGITUDE FASTER WITH THE MID-LEVEL TROUGH AXIS (ACROSS THE
NORTHERN PLAINS). IT HAD A FEW ENSEMBLE MEMBERS IN ITS `CAMP` BUT
SOMETHING CLOSER TO THE NAEFS/ECENS WOULD REPRESENT A BETTER
`PLACEHOLDER` WITH RESPECT TO WAVE AMPLITUDE ALONG/NORTH OF 50N
LATITUDE. WPC GRAPHICS PREFERRED A SLIGHTLY SLOWER EASTWARD
PROGRESSION OF THE FLOW---WHICH WOULD ALLOW SOME SHORTWAVE ENERGY
OVER THE CENTRAL AND SOUTHERN ROCKIES AN OPPORTUNITY TO EJECT
EASTWARD---AHEAD OF THE ECMWF/ECENS SOLUTION.

ACROSS THE EAST COAST AND SOUTHEAST...A NORTHWARD DRIFT OF THE
TROPICAL `DISTURBANCE` CONTINUES TO DISPLAY SOME SPREAD WITH
RESPECT TO TRAJECTORY ALONG 80W. THE DETERMINISTIC GUIDANCE
CONTINUES TO BE EXTREMELY SENSITIVE TO THE 30/00Z-30/12Z TIME
FRAME --- AND PRIMARILY ONCE THE LOW-LEVEL CIRCULATION HAS MOVED
VERY CLOSE TO THE SHORELINE (IF NOT INLAND). THE SURFACE GRAPHICS
WILL CONTINUE MAINTAINING A GENERAL NORTH TO NORTHEAST PROGRESSION
OF THE `DISTURBANCE` AND ITS INTERACTION WITH A WEAK BAROCLINIC
ZONE DRAPE ALONG THE NC/VA BORDER AFTER 30/12Z. THIS PARTICULAR
`DISTURBANCE`---HAS NEVER BEEN PROJECTED TO BECOME A
VERTICALLY-STACKED CYCLONE...AND THE 27/00Z GUIDANCE HAS NOT
CHANGED ITS TUNE IN THIS REGARD. THE NATIONAL HURRICANE CENTER
CONTINUES TO MONITOR THIS `DISTURBANCE` AND PLEASE REFER TO THEIR
PRODUCT SUITE FOR DETAILED INFORMATION.

VOJTESAK













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