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000
FXUS65 KREV 241005
AFDREV

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RENO NV
305 AM PDT FRI MAY 24 2013

.SYNOPSIS...
LOW PRESSURE WILL REMAIN OVER THE PACIFIC NORTHWEST THROUGH THE
THE MEMORIAL DAY WEEKEND BRINGING SLIGHTLY BELOW AVERAGE
TEMPERATURES. A DISTURBANCE WILL MOVE AROUND THE LOW ON SATURDAY
NIGHT AND SUNDAY, BRINGING A CHANCE OF SHOWERS AND THUNDERSTORMS
NORTH OF SUSANVILLE AND GERLACH. ANOTHER LOW WILL MOVE INTO
NORTHERN CALIFORNIA LATE ON MEMORIAL DAY, WITH SHOWERS POSSIBLE
FOR THE SIERRA AND WESTERN NEVADA.
&&

.SHORT TERM...
MAIN SHORT TERM FORECAST CHANGE WAS TO INCREASE POP SUNDAY NORTH
OF SUSANVILLE AND GERLACH.

A TROUGH WILL LOITER OVER THE PACIFIC NORTHWEST AND BRITISH
COLUMBIA THROUGH THE WEEKEND AS IT REMAINS BLOCKED BY A RIDGE
OVER NORTHERN CANADA. FOR TODAY, NORTHEAST CALIFORNIA AND WESTERN
NEVADA WILL BE UNDER DRY AND STABLE WESTERLY FLOW TO THE SOUTH OF
THE UPPER LOW. THE FLOW WILL ALSO BRING IN MUCH WARMER AIR AS
COMPARED TO YESTERDAY WITH HIGHS JUMPING TO WITHIN A FEW DEGREES
OF AVERAGE. BY SATURDAY AFTERNOON, MOISTURE WILL BEGIN INCREASING
(ESPECIALLY NORTH OF INTERSTATE 80) AHEAD OF AN UPPER DISTURBANCE
CURRENTLY OVER THE FAR NORTHEAST PACIFIC. THIS WILL BRING
INCREASING CLOUDS AND A LOW CHANCE OF SHOWERS NORTH OF SUSANVILLE
AND GERLACH BY MID TO LATE AFTERNOON SATURDAY.

THE AFOREMENTIONED DISTURBANCE WILL MOVE INTO OREGON AND FAR
NORTHERN CALIFORNIA BY SUNDAY AFTERNOON. MOST OF THE REGION WILL
REMAIN TOO DRY AND STABLE FOR SHOWERS BUT THE THERMAL PACKING
BETWEEN NORTHERN CALIFORNIA AND CENTRAL/SOUTHERN NEVADA WILL
PRODUCE A BREEZY DAY. FOR AREAS NORTH OF SUSANVILLE AND GERLACH,
THERE MAY BE ENOUGH INSTABILITY/LIFT FOR SCATTERED SHOWERS AND
EVEN A THUNDERSTORM OR TWO AS THAT AREA WILL BE CLOSER TO THE CORE
OF THE UPPER DISTURBANCE AND ASSOCIATED JET STREAK FORCING.
SNYDER

.LONG TERM...MONDAY THROUGH THURSDAY...
MADE ONLY A FEW MINOR CHANGES TO THE CURRENT FORECAST AS MEDIUM
RANGE MODELS ARE STARTING TO DIVERGE A BIT MORE EARLY IN THE
FORECAST. THE OPERATIONAL MODELS ALL START WITH A LONG WAVE TROUGH
MOVING INTO THE WESTERN U.S. MONDAY SPREADING PCPN ACROSS NRN CA. BY
TUESDAY MORNING THE ECMWF STARTS TO DEVELOP A SPLIT FLOW DROPPING
THE MAIN LOW DOWN THE SPINE OF THE SIERRA. A FEW GEFS MEMBERS ARE
ALSO STARTING TO SHOW THIS SOLUTION WHILE THE OPERATIONAL GFS AND
GEM ARE MORE PROGRESSIVE WITH THE TROUGH.

THE SPLIT WOULD RESULT IN LESS WIND OVER THE REGION AND ALSO A
DECREASED CHANCE FOR PCPN ACROSS THE NRN CWA WHILE THE GFS AND GEM
WOULD SUPPORT A LITTLE MORE WIND AND THE BETTER POP CHANCES OVER THE
FAR NORTH.

BY LATE WEDNESDAY THE GEM HAS A BROAD UPPER LOW OVER THE PAC NW WITH
ZONAL FLOW OVER OUR AREA WHILE THE GFS AND ECMWF BOTH HAVE MORE OF A
NW FLOW OVER THE REGION...BUT ENOUGH PROXIMITY TO THE TROUGH IN WRN
CANADA AND THE GULF OF ALASKA TO MAINTAIN MENTION OF VERY LOW POPS
OVER THE NRN CWA. SOME RIDGING IS HINTED AT BY THURSDAY.

WITH MODEL DISAGREEMENTS STILL FAIRLY PRONOUNCED AND THE GEFS
ENSEMBLE MEMBERS STARTING TO SHOW MORE SPREAD...AM NOT INCLINED TO
MAKE SIGNIFICANT CHANGES TO THE CURRENT FORECAST. 20
&&

.AVIATION...
UPPER LOW REMAINS NORTH OF THE REGION THROUGH SATURDAY WITH A SHORT
WAVE ROTATING NEAR THE NRN FORECAST AREA LATE TONIGHT. THE PRESENCE
OF THIS LOW WILL MEAN BREEZY AFTERNOON WINDS FOR MOST AREAS WITH
GUSTS IN TO THE 25-30 KT RANGE EAST OF THE SIERRA...BUT STILL VFR
CONDITIONS.

A MORE VIGOROUS SHORT WAVE DIPS SOUTH INTO THE REGION SATURDAY WITH
SHOWERS OVER THE FAR NRN FORECAST AREA POSSIBLE BY SATURDAY
AFTN/EVNG. EVEN WITH THE POSSIBILITY OF SHOWERS DO NOT THINK
CONDITIONS WILL DETERIORATE BELOW VFR FOR MOST LOCATIONS. 20
&&


.REV WATCHES/WARNINGS/ADVISORIES...
NV...NONE.
CA...NONE.
&&

$$

FOR MORE INFORMATION FROM THE NATIONAL WEATHER SERVICE VISIT...
HTTP://WEATHER.GOV/RENO (ALL LOWER CASE)