Wildfire in Oregon, September 13 to 30, 2014

AREA FORECAST DISCUSSION...CORRECTED
NATIONAL WEATHER SERVICE MEDFORD OR
839 AM PDT SAT SEP 13 2014

.DISCUSSION...TODAY AND SUNDAY WILL BE YET MORE DAYS WITH ABOVE NORMAL
TEMPERATURES...ABOUT 10 DEGREES ABOVE NORMAL FOR MOST OF THE AREA.
A WEAK DISTURBANCE WILL SEND SOME HIGH CLOUDS OVER THE REGION
TODAY. OTHERWISE...SMOKE FROM FIRES OVER SISKIYOU COUNTY WILL
FOLLOW A SIMILAR PATH TO THE NORTH AND EAST...WHILE LOW CLOUDS AND
FOG HUG THE SOUTHERN OREGON COAST SOUTH OF CAPE BLANCO.

A CHANGE IS ON THE WAY BY LATE MONDAY AS MODELS AGREE ON A COOLDOWN DUE
TO AN APPROACHING TROUGH. THIS COOLDOWN WILL BE ACCOMPANIED BY
GUSTY SOUTHERLY WINDS...SOMETHING THAT HASN'T OCCURRED OVER THE
REGION FOR A LONG WHILE.

PLEASE SEE THE PREVIOUS DISCUSSION BELOW FOR MORE DETAILS ON THE
COOLDOWN AND THE POTENTIAL FOR SOME PRECIPITATION WEST OF THE
CASCADES.

&&

.AVIATION...VFR WILL PREVAIL OVER MOST THE AREA THROUGH TONIGHT
WITH THE EXCEPTION OF AREAS OF IFR CIGS IN COASTAL FOG ALONG THE
CURRY COAST. FOG IS PRESENT THIS MORNING FOR LOCATIONS SOUTH OF
CAPE BLANCO AND IS EXPECTED TO BECOME ISOLATED BY EARLY
AFTERNOON...BUT THEN WILL RETURN TO THE CURRY COAST AGAIN SATURDAY
EVENING. AREAS OF SMOKE AND HAZE FROM WILDFIRES WILL ALSO AFFECT
SOME INLAND AREAS, MAINLY IN SISKIYOU COUNTY AND ADJACENT AREAS TO
THE NORTHEAST. /CC

&&

.MARINE...UPDATED 600 AM PDT SAT 13 SEP 2014...A VERY WEAK
THERMAL TROUGH WILL REMAIN OVER THE AREA THROUGH EARLY MONDAY.
THIS WILL KEEP LIGHT WINDS AND SEAS OVER THE WATERS. THEN SOME
INCREASED SOUTHERLY WINDS ARE EXPECTED MONDAY AFTERNOON AS A WEAK
LOW APPROACHES THE COAST. WINDS ARE EXPECTED TO REMAIN BELOW SMALL
CRAFT CONDITIONS ON MONDAY. THEN A STRONGER LOW PRESSURE SYSTEM
AROUND MID WEEK MAY BRINGING INCREASED SOUTHERLY WINDS ALONG WITH
BUILDING SEAS. INITIALLY, A MIX OF WESTERLY AND SOUTHERLY SWELL IS
EXPECTED TO BUILD INTO THE COASTAL WATERS TUESDAY INTO WEDNESDAY.
THEN INCREASING SOUTH WINDS AND SOME LINGERING SOUTHERLY AND
WESTERLY SWELL MAY RESULT IN STEEP SEAS IN THE COASTAL WATERS
WEDNESDAY EVENING INTO THURSDAY. /CC

&&

.PREV DISCUSSION... /ISSUED 304 AM PDT SAT SEP 13 2014/

DISCUSSION...CURRENT SURFACE ANALYSIS SHOWS THE THERMAL TROUGH ALONG
THE OREGON COAST. THE GRADIENTS ARE WEAKER COMPARED TO RECENT NIGHTS
WHICH HAS RESULTED IN LIGHTER WINDS OVER THE MID SLOPES AND RIDGES.
NOT MUCH CHANGE IN THE WEATHER IS EXPECTED FOR THE REST OF THE
WEEKEND WITH DRY CONDITIONS AND ABOVE NORMAL TEMPERATURES IN THE
AFTERNOON. TEMPERATURES WILL COOL DOWN QUICKLY AFTER DARK AND NOW
THAT NIGHTS ARE BECOMING LONGER, WE'LL CONTINUE TO HAVE COOL
MORNINGS AND HOT AFTERNOONS. WINDS ALOFT WILL BE FROM THE SOUTHWEST
AND SMOKE FROM THE FIRES IN WESTERN SISKIYOU COUNTY WILL CONTINUE TO
MOVE NORTHEAST AND AT LEAST THE SOUTHERN END OF THE ROGUE VALLEY
WILL HAVE PATCHY AREAS OF SMOKE. SKIES FOR THE MOST PART WILL BE
CLEAR WITH A FEW HIGH CLOUDS MOVING IN FROM THE SOUTHWEST. MARINE
STRATUS CONTINUES TO HANG ALONG THE SOUTH COAST NEAR BROOKINGS. IN
FACT IT MADE ITS WAY INTO BROOKINGS. IT HAS SINCE RETREATED BACK
SOUTH, BUT THIS SHOULD ONLY BE TEMPORARY AND IS EXPECTED TO CREEP
BACK NORTH UP TOWARDS GOLD BEACH LATE THIS AFTERNOON.

SUNDAY WILL BE SIMILAR TO TODAY, EXCEPT THE MARINE STRATUS WILL
CONTINUE TO MOVE NORTH ALONG THE COAST AND MOST OF THE MARINE
WATERS.

THE MODELS ARE IN SIMILAR AGREEMENT SHOWING A SHORTWAVE MOVING
NORTHEAST TOWARDS THE PAC NW MONDAY. THE NAM HAS TRENDED FARTHER
EAST. THE GFS IS SLIGHTLY FASTER AND WEST AND THE EC IS MUCH WEAKER.
THE NAM HINTS AT INCREASING MID LEVEL MOISTURE AND MARGINAL
INSTABILITY IN THE AFTERNOON AND EVENING. HOWEVER THERE IS LITTLE OR
NO TRIGGER. THE GFS SHOWS MID LEVEL MOISTURE INCREASING SOME, BUT
LIFTED INDICES ARE POSITIVE AND LITTLE OR NO CAPE. THEREFORE
DECIDED TO INCREASE POPS ALONG AND EAST OF THE CASCADES MONDAY
AFTERNOON AND EVENING, BUT KEEPING ANY MENTION OF STORMS OUT.
FURTHER SHIFTS MAY NEED TO INCREASE POPS IF THE GFS AND EC COME IN
BETTER AGREEMENT WITH THE NAM. IF NOTHING ELSE, THE FLOW WILL BECOME
MORE SOUTHERLY AND IT'S POSSIBLE THE SMOKE COULD MAKE ITS WAY INTO
THE UMPQUA BASIN.

THE EC AND GFS CONTINUE TO SHOW A CHANGE IN THE PATTERN STARTING TO
UNFOLD STARTING TUESDAY. THE MODELS SHOW A BROAD UPPER TROUGH
DEVELOPING NEAR 36N/137W TUESDAY, THEN TRACKING NORTHEAST TOWARDS
THE FORECAST AREA WEDNESDAY. THE GFS SHOWS THE TROUGH DEVELOPING
INTO AN UPPER LOW WEDNESDAY WHILE THE EC AND REMAIN WEAKER. EITHER
WAY, IT LOOKS LIKE WE COULD SEE OUR FIRST SIGNIFICANT PRECIPITATION
EVENT (AT LEAST IN A RELATIVE SENSE) SINCE LAST SPRING. GIVEN THE
EXTENT AND DURATION OF DRYNESS OVER THE REGION, THIS WILL BE WELCOME
NEWS FOR MOST, ESPECIALLY FOR FIRE WEATHER FOLKS. THE EC IS THE
WETTER OF THE THREE MODELS (GFS AND GEM) AND SUSPECT IT MAY BE TOO
WET. ALSO THE TRACK OF THE UPPER LOW IS SUCH THAT THE COAST, COAST
RANGE AND WEST SIDE AND WESTERN SISKIYOU COUNTY STAND THE BEST
CHANCE OF GETTING MEASURABLE PRECIPITATION. THE QUESTION IS HOW MUCH
WHICH AT THIS TIME THE CONFIDENCE IS LOW. TEMPERATURES WILL COOL
DOWN AND WE COULD SEE THEM DROP NEAR OR SLIGHTLY BELOW NORMAL
WEDNESDAY AND THURSDAY.

THE ONE CONCERN WE HAVE IS WE COULD SEE GUSTY WINDS ESPECIALLY OVER
THE RIDGES IN WESTERN SISKIYOU COUNTY AND ALONG AND EAST OF THE
CASCADES WEDNESDAY AFTERNOON THROUGH THURSDAY NIGHT. I DON'T THINK
THEY WILL BE STRONG ENOUGH TO WARRANT ANY ADVISORIES, BUT WILL BE OF
CONCERN FOR THE ONGOING FIRE FIGHTING EFFORTS.

DRY AND MILDER CONDITIONS RETURN BY THE END OF NEXT WEEK AS RIDGING
BUILDS OVER THE AREA IN THE WAKE OF THE UPPER TROUGH/LOW.
TEMPERATURES WILL REBOUND AND ARE LIKELY TO GET NEAR OR SLIGHTLY
ABOVE NORMAL. -PETRUCELLI

&&

.MFR WATCHES/WARNINGS/ADVISORIES...
OR...
CA...NONE.

PACIFIC COASTAL WATERS...NONE.

NSK/NSK/CC