Area Forecast Discussion
Issued by NWS Medford, OR

Home | Current Version | Previous Version | Text Only | Print | Product List | Glossary On
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50
000
FXUS66 KMFR 040301
AFDMFR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MEDFORD OR
801 PM PDT FRI JUL 3 2015

.DISCUSSION...04/00Z NAM IN.

SOME SHOWERS DEVELOPED FRIDAY AFTERNOON AND EVENING ACROSS
SISKIYOU AND MODOC COUNTIES...AND SEVERAL THUNDERSTORMS DEVELOPED
OVER SOUTHERN LAKE COUNTY AND SOUTHEAST SISKIYOU COUNTY. THE
NORTHERN CALIFORNIA SHOWERS MOVED FROM EAST TO WEST AT A FAIRLY
GOOD CLIP...WHILE THE LAKE COUNTY THUNDERSTORMS DRIFTED SLOWLY
NORTH. THIS SHOWED WHERE THE COL WAS IN THE DEFORMATION ZONE
CURRENTLY OVER THE CWA. SOME THUNDERSTORMS PERSIST AT THIS TIME
OVER FAR EASTERN MODOC COUNTY...AND IT LOOKS LIKE WE`RE GOING TO
HAVE A FEW MORE HOURS OF ACTIVITY AROUND THERE.

AN UPPER LEVEL LOW REMAINS OFF THE SOUTHERN CALIFORNIA COAST THIS
EVENING AND A STRONG HIGH PERSISTS OVER THE GREAT BASIN. IN
BETWEEN IS SOUTHERLY FLOW ALOFT WHICH IS BRINGING MONSOONAL
MOISTURE TO THE AREA. THE SOUTHERLIES ARE HITTING A DIFLUENT
AREA/DEFORMATION ZONE AS THEY MOVE INTO OREGON. SO...THE
MOISTURE...COMBINED WITH DIFLUENCE ALOFT AND STRONG SURFACE
HEATING ARE RESPONSIBLE FOR THE SHOWERS AND THUNDERSTORMS THAT
DEVELOPED FRIDAY.

ALL OF THE ABOVE FEATURES WILL BE THERE SATURDAY AFTERNOON...BUT
IT WILL BE DISPLACED FARTHER SOUTH. AT THIS POINT IT LOOKS LIKE
THE MOST FAVORED AREA FOR CONVECTION WILL BE ACROSS SISKIYOU AND
MODOC COUNTIES. MODEL STABILITY INDICES SUPPORT THIS...BUT ALSO
SHOW A STABLE AREA BETWEEN TWO AREAS OF CONVECTION. IT MAY LOOK A
BIT ODD SATURDAY AFTERNOON AS CONVECTION OVER SISKIYOU COUNTY WILL
HEAD WEST WHILE MODOC COUNTY CONVECTION WILL HEAD EAST. MAY GET
SOME SHOWERS OVER THE CASCADES AS WELL BUT SUPPORT IS WEAKER
THERE. IF THEY DO DEVELOP THEY WILL BE SLOW MOVERS.

MORE OF THE SAME ON SUNDAY...BUT A SHORT WAVE WILL BE IN THE MIX
THEN. THE LOCATION OF THIS WAVE WILL LIKELY BE A BIT DIFFERENT
THAN CURRENTLY FORECAST...BUT OVERALL LOOKS LIKE CONVECTION WILL
BE MORE WIDESPREAD...BUT WEAKER.

THROUGH ALL THIS...THE INCREASING MOISTURE AND CLOUD COVER WILL
BRING A SLOW COOLING TREND TO THE AREA. HOWEVER...HUMIDITIES WILL
BE HIGHER SO IT WILL ACTUALLY FEEL HOTTER.

THE ISOLATED TO SCATTERED SHOWER AND THUNDERSTORM PATTERN WILL
PERSIST OVER THE AREA MONDAY AND TUESDAY AS THE UPPER LOW
GRADUALLY MOVES TOWARDS THE NORTHERN CALIFORNIA COAST AND MOISTURE
AND ENERGY MOVES AROUND THE LOW AND INTO THE AREA. GIVEN THE
PATTERN OF SOUTHEAST MOISTURE FLOW AROUND THIS LOW...EXPECT
INCREASED CHANCES FOR SHOWERS AND THUNDERSTORMS WEST OF THE
CASCADES...POSSIBLY EVEN NEAR THE COAST MONDAY AND TUESDAY.
TEMPERATURES WILL CONTINUE TO COOL...BUT IT WILL STILL BE HOT.

LONG TERM DISCUSSION FROM THE FRIDAY AFTERNOON AFD..WEDNESDAY
THROUGH FRIDAY. MODELS AND ENSEMBLE SOLUTIONS ARE LEANING TOWARDS
BRINGING THE UPPER TROUGH INTO NORTHERN CALIFORNIA WEDNESDAY
THROUGH FRIDAY. THIS WILL BRING A PATTERN WITH COOLER TEMPERATURES
LATE NEXT WEEK AS WELL AS CONTINUED SHOWERS AND THUNDERSTORMS.
THERE IS LOW CONFIDENCE THOUGH ON THE TRACK AND TIMING OF THE LOW
AS MOVES INLAND. SO HAVE KEPT TEMPERATURES ACROSS THE AREA NEAR OR
JUST BELOW NORMALS FOR THURSDAY AND FRIDAY.

&&

.AVIATION...FOR THE 04/00Z TAF CYCLE...ALONG THE COAST...IFR AND
LIFR CONDITIONS WILL RETURN MAINLY FROM CAPE BLANCO NORTHWARD ABOUT
MIDNIGHT AND PERSIST THROUGH EARLY MORNING. VFR CONDITIONS WILL
PREVAIL FOR THE REMAINDER OF THE AREA...BUT ISOLATED EVENING
THUNDERSTORMS ARE EXPECTED OVER NORTHERN CALIFORNIA AND SOUTHERN
LAKE AND KLAMATH COUNTIES. THUNDERSTORMS WILL FORM IN SIMILAR AREAS
TOMORROW AFTERNOON AND EVENING. FOR THE COAST...STRATUS AND FOG
SHOULD CLEAR SATURDAY MORNING...BUT THE GENERAL COVERAGE AND
DURATION OF COASTAL FOG AND STRATUS IS EXPECTED TO INCREASE LATER
THIS WEEKEND AND INTO EARLY NEXT WEEK. SK

&&

.MARINE...UPDATED 200 PM PDT FRIDAY 3 JULY 2015...A THERMAL TROUGH
WILL PERSIST NEAR THE COAST INTO SATURDAY. SMALL CRAFT ADVISORY
NORTH WINDS AND STEEP SEAS WILL PREVAIL DURING THIS TIME
FRAME...WITH SMALL CRAFT CONDITIONS FOR WINDS GENERALLY BEYOND 5NM
FROM SHORE. WINDS AND WAVES WILL GRADUALLY SUBSIDE LATER THIS
WEEKEND...WITH STRATUS AND FOG AFFECTING MOST OF THE COASTAL WATERS
BY SUNDAY. FURTHER OUT IN TIME...SEAS WILL LIKELY REMAIN BELOW 6
FEET THROUGH THE MIDDLE OF NEXT WEEK.

&&

.FIRE WEATHER...UPDATED 230 PM PDT FRIDAY 3 JULY 2015...HOT
WEATHER WILL PERSIST INTO THIS WEEKEND. AN INVERSION WILL BRING
CONTINUED MODERATE TO LOCALLY POOR RECOVERIES TO MANY RIDGES OVER
THE AREA AGAIN TONIGHT. MOISTURE ALOFT IS INCREASING TODAY, AND
ISOLATED AFTERNOON AND EVENING THUNDERSTORMS ARE POSSIBLE OVER
NORTHERN CALIFORNIA AND EAST OF THE CASCADES THIS EVENING. ON
SATURDAY, MOISTURE FLOW WILL BE ENHANCED, AND SCATTERED
THUNDERSTORMS ARE EXPECTED TO DEVELOP OVER MUCH OF NORTHERN
CALIFORNIA FROM THE TRINITY ALPS TO THE WARNER MOUNTAINS, AND ALSO
OVER THE SOUTHERN HALVES OF LAKE AND KLAMATH COUNTIES. MODEL
SOLUTIONS DEPICT AREAS OF INSTABILITY PERSISTING OVERNIGHT, AND
DUE TO THIS, HAVE KEPT A CHANCE FOR NOCTURNAL STORMS IN PLACE
THROUGH SATURDAY NIGHT INTO EARLY SUNDAY MORNING. SCATTERED
THUNDERSTORMS ARE LIKELY TO RETURN SUNDAY AFTERNOON AND EVENING AS
DAYTIME HEATING INCREASES, AND MOISTURE INFLOW REMAINS AIMED AT
OUR AREA. WE ARE EXPECTING LOW LEVELS OF THE ATMOSPHERE TO REMAIN
DRY, AND ALTHOUGH MOST OF THE STORMS SATURDAY AND SUNDAY SHOULD BE
WET, ABUNDANT LIGHTNING STRIKES OUTSIDE STORM CORES WOULD BE DRY.
THE DRY LOW LEVELS WOULD ALSO INCREASE THE POTENTIAL FOR GUSTY AND
ERRATIC WINDS IN THE VICINITY OF THUNDERSTORMS. WITH THE POTENTIAL
OF NUMEROUS NEW STARTS, INITIAL ATTACK RESOURCES COULD BE
STRETCHED THIN. FOR THESE REASONS, HAVE ISSUED A FIRE WEATHER
WATCH FOR SATURDAY EVENING INTO SUNDAY EVENING, AND WILL WATCH THE
MOST RECENT MODEL RUNS TO FURTHER REFINE THE AREA OF MOST CONCERN.

&&

.MFR WATCHES/WARNINGS/ADVISORIES...
OR...FIRE WEATHER WATCH FROM SATURDAY EVENING THROUGH SUNDAY EVENING
        FOR ORZ624-625.
     HEAT ADVISORY UNTIL 11 PM PDT THIS EVENING FOR ORZ023.
     HEAT ADVISORY UNTIL 11 PM PDT SATURDAY FOR ORZ024-026.

CA...FIRE WEATHER WATCH FROM SATURDAY EVENING THROUGH SUNDAY EVENING
        FOR CAZ280-281-284-285.
     HEAT ADVISORY UNTIL 11 PM PDT SATURDAY FOR CAZ080-081.

PACIFIC COASTAL WATERS...SMALL CRAFT ADVISORY FOR WINDS UNTIL 2 PM
        PDT SATURDAY FOR PZZ356-376.
     SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS UNTIL 5 PM PDT SATURDAY
        FOR PZZ350-356-370-376.

$$

15/15/15



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