Prognostic Meteorological Discussion
Issued by NWS

Current Version | Previous Version | Graphics & Text | Print | Product List | Glossary On
Versions: 1 2
000
FXUS02 KWBC 261601
PMDEPD

EXTENDED FORECAST DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
1200 PM EDT FRI MAY 26 2017

VALID 12Z MON MAY 29 2017 - 12Z FRI JUN 02 2017

PATTERN OVERVIEW AND MODEL PREFERENCES
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
THE MEDIUM-RANGE PERIOD THROUGH NEXT FRIDAY WILL FEATURE A
UPPER-LEVEL TROUGH/CLOSED LOW SLOWLY MOVING EASTWARD TOWARDS THE
NORTHEASTERN U.S. AS THE NEXT UPPER TROUGH REACHES THE PACIFIC
NORTHWEST WHILE A CLOSED LOW LIKELY DIPS INTO THE DESERT
SOUTHWEST.  MODEL GUIDANCE THIS MORNING DEPICTS THIS GENERAL
EVOLUTION OF THE SYNOPTIC PATTERN BUT WITH SOME NOTABLE SMALLER
SCALE DIFFERENCES...ESPECIALLY REGARDING THE MANY
SHORTWAVES/DISTURBANCES THAT ARE FORECAST TO ROTATE AROUND THE
SLOW-MOVING CLOSED LOW AS IT MOVES OVER THE GREAT LAKES EARLY TO
MIDDLE OF NEXT WEEK.  REGARDING THE CLOSED LOW FORECAST TO MOVE
OVER THE DESERT SOUTHWEST LATER NEXT WEEK...THE GFS AND CANADIAN
MODELS ARE MORE ENTHUSIASTIC IN ITS DEVELOPMENT.  THIS IS IN
CONTRAST WITH THE ECMWF WHICH SHOWS LESS DEVELOPMENT AND A FASTER
EASTWARD PROGRESSION INTO NORTHERN MEXICO BY NEXT FRIDAY.  A
MULTI-MODEL CONSENSUS APPROACH WAS USED TO DERIVE THIS MORNING`S
WPC MEDIUM-RANGE GRIDS...WITH THE SAME PROPORTION GIVEN TO THE 00Z
ECMWF/EC MEAN AND THE 06Z GFS/GEFS...WITH SLIGHTLY LESS WEIGHT
GIVEN TO THE CANADIAN MODEL.  SOME 00Z NAEFS WERE INCLUDED FOR DAY
5 THROUGH 7 IN ADDITION TO THE 00Z EC MEAN AND 06Z GEFS


WEATHER HIGHLIGHTS
~~~~~~~~~~~~~~~~~~
COOLER THAN NORMAL TEMPERATURES ARE EXPECTED TO CONTINUE INTO NEXT
WEEK FROM THE PLAINS EASTWARD TOWARDS THE NORTHEASTERN U.S. AS THE
UPPER-LEVEL CLOSED LOW REMAINS IN THE VICINITY.  MEANWHILE...WARM
AND DRY CONDITIONS ARE EXPECTED ACROSS MUCH OF THE WESTERN THIRD
OF THE NATION INTO THE MIDDLE OF NEXT WEEK BEFORE A COLD FRONT
ARRIVES LATE NEXT WEEK.  THE GREATEST POSITIVE TEMPERATURE
ANOMALIES SHOULD BE OVER THE PACIFIC NORTHWEST WHERE DAYTIME
TEMPERATURES COULD SURPASS 90F IN SOME LOCATIONS.

MOISTURE ADVECTING NORTHWARD OUT OF THE GULF OF MEXICO WILL FUEL
POTENTIALLY HEAVY RAIN AND THUNDERSTORMS ALONG/AHEAD OF A FRONTAL
BOUNDARY PRESSING EAST/SOUTHEASTWARD OUT OF THE SOUTHERN PLAINS
INTO THE MID-SOUTH EARLY NEXT WEEK...WITH MODEST AMOUNTS ACROSS
THE NORTHEAST/MID-ATLANTIC STATES.  THE TAIL END OF THE BOUNDARY
IS EXPECTED TO STALL AND WILL BEGIN TO INTERACT WITH THE CLOSED
LOW APPROACHING THE SOUTHWEST...BRINGING ADDITIONAL HEAVY RAINFALL
TO PORTIONS OF THE SOUTHERN PLAINS EARLY TO MID NEXT WEEK WHICH
COULD SPREAD QUICKLY ACROSS THE MID-MISSISSIPPI VALLEY TOWARDS THE
NORTHERN MID-ATLANTIC STATES.

KONG/ROTH/GERHARDT

$$





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