Severe Thunderstorm Warning 3, NWS Fairbanks, AK

000 
WWAK59 PAFG 222314
SVSAFG

SEVERE WEATHER STATEMENT
NATIONAL WEATHER SERVICE FAIRBANKS AK
314 PM AKDT SUN JUN 22 2008

AKZ222-224-222324-
/O.EXP.PAFG.SV.W.0003.000000T0000Z-080622T2315Z/
MIDDLE TANANA VALLEY AK-
UPPER TANANA VALLEY AND THE FORTYMILE COUNTRY AK-
314 PM AKDT SUN JUN 22 2008

...THE SEVERE THUNDERSTORM WARNING FOR UPPER TANANA VALLEY AND THE
FORTYMILE COUNTRY AND MIDDLE TANANA VALLEY WILL EXPIRE AT 315 PM
AKDT...

LAT...LON 6442 14588 6444 14596 6445 14598 6445 14604
      6449 14621 6458 14590 6452 14579
TIME...MOT...LOC 2314Z 077DEG 6KT 6452 14604

$$

ES

NORTHERN ALASKA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE FAIRBANKS AK
1258 PM AKDT SUN JUN 22 2008

.DISCUSSION...

ALOFT...
A HIGH PRESSURE RIDGE ALOFT CURRENTLY EXTENDS FROM THE CENTRAL
BROOKS RANGE EASTWARD TO GREAT BEAR LAKE THEN SOUTHEAST TO GREAT
SLAVE LAKE...WITH LIGHT EASTERLY FLOW OVER THE SOUTHERN INTERIOR
AND THE ALASKA RANGE. A WEAK SHORT WAVE TROUGH ALOFT NOW OVER THE
SOUTHERN YUKON TERRITORY WILL MOVE WESTWARD ALONG THE BOTTOM
SIDE OF THE RIDGE...EXTENDING FROM CENTRAL SOUTHWARD BY 00Z MON
AND MOVING TO THE SOUTHWEST INTERIOR BY 12Z MON. FORECASTS
FOR LATER IN THE WEEK BECOME MORE UNCERTAIN AS THE UPPER AIR
SOLUTIONS DIVERGE...GFS PICKING UP TWO MORE WEAK SHORT WAVES
MOVING AROUND THE BOTTOM OF THE RIDGE WHILE THE NAM AND ECMWF
SHARPEN A RIDGE LINE OVER ALASKA...BUT WITH RIDGE LINE POSITIONS
OVER ALASKA DIFFERING CONSIDERABLY BY 00Z THU.

SURFACE...
UNSTABLE AIR COVERS MOST OF THE INTERIOR AND BROOKS RANGE TODAY...
WITH THE AXIS OF A BROAD THERMAL TROUGH EXTENDING EAST-WEST ACROSS
THE CENTRAL INTERIOR. THE THERMAL TROUGH SHOULD PROVIDE SOME
LARGE-SCALE LOW LEVEL CONVERGENCE...WITH AN ASSIST FROM UPPER
DYNAMICS ASSOCIATED WITH THE WESTWARD MOVING SHORT WAVE.
THE MOST ACTIVE AREA FOR CONVECTION THIS AFTERNOON AND EVENING
IS EXPECTED TO BE IN ZONES 216-221-222-223-224...WHERE GFS MODEL
FORECAST LIFTED INDEXES ARE TYPICALLY 0 T0 -2 WITH A FEW
SPOTS OF -3...AND CAPES TO 400-800 J/KG. BY LATER THIS
EVENING...THE AREA OF CONVECTION WILL SHIFT A LITTLE FARTHER
TO THE NORTH AND WEST...WITH THE AIRMASS BEGINNING TO
STABILIZE OVER THE ALASKA RANGE AND NEARBY AREAS IN THE SOUTHERN
INTERIOR. WITH THE SHORT WAVE MOVING EASTWARD THIS AFTERNOON AND
TONIGHT...CONVECTION MAY LAST WELL INTO THE NIGHT. SEVERAL
THUNDERSTORMS HAVE ALREADY MET SEVERE THUNDERSTORM WARNING
CRITERIA BASED ON DOPPLER RADAR DATA.

SOUTHERLY GAP WINDS ARE EXPECTED TO DEVELOP IN THE ALASKA
RANGE LATER TODAY...CONTINUING OVERNIGHT AS THE THERMAL
LOW CENTER GRADUALLY MIGRATES WESTWARD AND RIDGING BUILDS
OVER THE EASTERN NORTH GULF COAST. SUPPORT ALOFT IS
NONEXISTENT...SO WINDS WILL BE LIMITED TO LOW LEVELS...
MAX GUSTS PROBABLY AROUND 25 KT.

FOR MONDAY...THE MOST UNSTABLE AIRMASS IS EXPECTED TO BE
OVER ZONES 205-206-216-217-218-220-224. THE AXIS OF THE
BROAD SURFACE TROUGH WILL EXTEND FROM EAGLE TO CHANDALAR
LAKE AND WESTWARD.

EXCEPT FOR AREAS OF MINIMUM BRISK WINDS EXPECTED IN PKZ245...MARINE
AREA WINDS WILL REMAIN BELOW ADVISORY LEVELS THROUGH 12Z TUE.

DRY CONDITIONS WILL CONTINUE OVER THE WEST AND NORTHWEST
COASTS...AND MAINLY EAST TO NORTHEAST WINDS WILL CONTINUE
ALONG THE ARCTIC COAST. WITH RIDGING ALOFT AND LOW RH PROGGED
AT LOW LEVELS ALONG THE ARCTIC COAST...LATE NIGHT AND EARLY
MORNING FOG COVERAGE IS EXPECTED TO BE MINIMAL. THE MOST
LIKELY AREA FOR ANY FOG DEVELOPMENT WOULD BE ALONG THE
ARCTIC COAST...GOES VIS LOOP SHOWING AREAS OF OPEN WATER
IN EASTERN PKZ245...AND MUCH MORE EXTENSIVE FARTHER TO THE
EAST IN CANADIAN WATERS. BARTER ISLAND REPORTED A FEW INTERVALS
OF FOG OVERNIGHT...BARROW AND DEADHORSE WERE FOG-FREE.

COASTAL HAZARD POTENTIAL DAYS 3 AND 4...NONE

&&

.FIRE WEATHER...
NO PROBLEM AREAS.

&&

.HYDROLOGY...
LOCALLY HEAVY RAINFALL AMOUNTS LIKELY IN HEAVIER
THUNDERSTORMS THIS AFTERNOON AND EVENING MAY BRING
SMALL STREAMS UP TO BANK FULL OR OVER BANK FULL
STAGES.

&&

.AFG WATCHES/WARNINGS/ADVISORIES...
BRISK WIND ADVISORY FOR PKZ245.
SMALL STREAM FLOOD ADVISORY FOR AKZ220-AKZ224

&&

RF JUN 08