243
FXUS66 KMFR 242143
AFDMFR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MEDFORD OR
243 PM PDT THU OCT 24 2024
SHORT TERM...THURSDAY NIGHT THROUGH SATURDAY NIGHT
UPPER LEVEL
RIDGING CENTERED OVER THE SOUTHWEST US AND MEXICO WILL STABLE
CONDITIONS AND WARMING TO NORTHERN CALIFORNIA AND SOUTHERN
CALIFORNIA TODAY AND FRIDAY. TODAY'S HIGHS WILL BE NEAR SEASONAL
LEVELS, WITH TEMPERATURES 5 TO 10 DEGREES ABOVE NORMAL ON FRIDAY AND
SATURDAY. THIS WILL RESULT IN THE OREGON COAST BEING IN THE MID TO
HIGH 60S. WEST SIDE VALLEYS WILL BE IN THE LOW TO MID 70S, AND AREAS
EAST OF THE CASCADES WILL BE IN THE LOW TO MID 60S.
FOR OVERNIGHT TEMPERATURES, THE POTENTIAL FOR FROST CONDITIONS
(TEMPERATURES BETWEEN 33 AND 36 DEGREES) REMAINS ON SOME WEST SIDE
VALLEYS TONIGHT. THE SCOTT, SHASTA, ILLINOIS, APPLEGATE, AND
NORTHERN ROGUE (GRANTS PASS TO CENTRAL POINT TO SHADY COVE) VALLEYS
HAVE A 30-50% CHANCE OF SEEING FROST CONDITIONS TONIGHT. THERE ARE
NO CONCERNS WEST OF THE CASCADES ON FRIDAY OR SATURDAY NIGHT. EAST
SIDE AREAS WILL BE IN THE MID 20S TO LOW 30S TONIGHT THEN SEE LOW TO
HIGH 30S INTO THE WEEKEND.
ON FRIDAY, A LOW PRESSURE SYSTEM WILL MOVE FROM THE GULF OF ALASKA
AND SETTLE WEST OF VANCOUVER ISLAND. THIS WILL ALLOW FOR AN ACTIVE
PERIOD STARTING ON FRIDAY EVENING AND CONTINUING INTO NEXT WEEK. A
WARM FRONT WILL BE THE FIRST FEATURE TO ARRIVE, BRINGING STEADY
RAINFALL TO THE OREGON COAST AND NEARBY AREAS. FOR FRIDAY EVENING
THROUGH SATURDAY EVENING, HIGH CHANCES OF PRECIPITATION (60-95%) WILL
BE OVER COOS AND CURRY COUNTY, WITH LESSER (30-60%)CHANCES OVER
DOUGLAS AND JOSEPHINE COUNTIES. SHOWERS SHOULD BE STEADY AND
UNIMPACTFUL, WITH COASTAL AREAS AND RANGES FORECAST TO GET 0.5 TO
1.0 INCHES OF RAINFALL IN THIS PERIOD. INLAND CURRY COUNTY
(COQUILLE, MYRTLE POINT) COULD GET 0.2 TO 0.3 INCHES AND THE
ILLINOIS VALLEY COULD GET 0.1 TO 0.2 INCHES.
NBM PROBABILISTIC GUIDANCE HAS A 25% FOR HIGHER TOTALS IN THESE
AREAS, AS WELL AS 0.25 INCHES OF RAIN INTO THE UMPQUA VALLEY. THESE
INCREASES MAY BE RELATED MORE TO TIMING THE ARRIVAL OF A COLD FRONT
MORE THAN THE ACTIVITY UNDER THIS WARM FRONT. CURRENTLY THE COLD
FRONT'S ARRIVAL STARTS THE LONG TERM DISCUSSION, BUT ANY CHANGE IN
THAT TIMING WOULD HAVE A MEANINGFUL IMPACT ON THE TIMING OF
PRECIPITATION FORECASTS. -TAD
LONG TERM
THE UPPER LOW IN THE GULF OF ALASKA WILL MOVE NEAR
THE COAST OF BRITISH COLUMBIA ON SUNDAY. THIS LOW IS FORECAST TO
TRACK SOUTHWARD OFF THE WASHINGTON COAST SUNDAY NIGHT INTO MONDAY.
A MODERATE TO STRONG COLD FRONT ASSOCIATED WITH THIS LOW IS
EXPECTED TO MOVE INLAND OVER THE REGION ON SUNDAY. THE NATIONAL
BLEND OF MODELS (NBM) ENSEMBLE IS INDICATING WIDEPSREAD MODERATE
RAINFALL WITH THIS FRONTAL PASSAGE, EXCEPT FOR LOCALLY HEAVIER
AMOUNTS ALONG THE COAST. HEAVIEST RAINFALL WILL BE ALONG THE COAST
AND INLAND INTO THE UMPQUA BASIN WITH THIS FRONT. THE NBM
INDICATES THERE IS A HIGH CHANCE (80- 100%) FOR AT LEAST A HALF
INCH OF RAIN ACROSS COOS CURRY, DOUGLAS, JOSEPHINE, WESTERN
SISKIYOU AND NORTHERN JACKSON COUNTIES WITH THIS FRONT AND A
75-95% CHANCE FOR AN INCH OR MORE OF RAINFALL ALONG THE IMMEDIATE
COAST AND INLAND ACROSS CURRY COUNTY. AREAS IS SOUTHERN CURRY
COUNTY, INCLUDING THE SOUTHERN KALMIOPSIS AND BROOKINGS AREA HAVE
A 50-75% CHANCE OF UP 2 INCHES OF RAINFALL. SNOWFALL MAY BE
LIMITED SUNDAY MORNING TO HIGHER PEAKS WITH SNOW LEVELS STARTING
OUT AROUND 7000-8500 FEET. ADDITIONALLY, MODELS INDICATE ENOUGH
INSTABILITY AND UPPER LEVEL SUPPORT FOR A SLIGHT CHANCE (15%) FOR
THUNDERSTORMS ALONG THE COAST AS THIS FRONT MOVES ONSHORE.
THEN, AS A DEEP UPPER TROUGH SETTLES OVER THE REGION, A COLD AND
SHOWERY AIR MASS IS IN PLACE LATE SUNDAY THROUGH MONDAY. ONSHORE
MOIST FLOW AND AN UPPER LEVEL JET WILL SUPPORT SCATTERED TO
WIDESPREAD MODERATE RAIN AND SNOW SHOWERS OVER THE AREA DURING THIS
PERIOD. SNOW LEVELS ARE FORECAST TO LOWER TO AS THE UPPER TROUGH
MOVES INTO THE REGION, DOWN TO AROUND 5000 FEET BEHIND THE FRONT
SUNDAY NIGHT INTO MONDAY. THE MOST RECENT NBM ENSEMBLE SUPPORTS
PERSISTENT LIGHT TO MODERATE SNOW FOCUSED OVER THE SOUTHERN OREGON
CASCADES SUNDAY NIGHT THROUGH MONDAY NIGHT, WITH HIGHER PASSES, SUCH
AS DIAMOND LAKE AND LAKE OF THE WOODS, SEEING A HIGH CHANCE (60-70%)
OF AT LEAST 4 INCHES OF SNOW AND A MODERATE CHANCE (40-50%)OF 6
INCHES OF SNOW DURING A 24 HOUR PERIOD. HIGHER AMOUNTS ARE EXPECTED
NEAR CRATER LAKE WITH THE NBM SUPPORTING A HIGH (75%) CHANCE FOR 8
INCHES OF SNOW AND A 60% CHANCE FOR 10 INCHES OF SNOW OR MORE. THIS
MAY RESULT IN HIGHER PASSES SEEING SNOW IMPACTS DURING THIS PERIOD.
LIGHT SHOWER ACTIVITY MAY LINGER ON TUESDAY AS THE UPPER TROUGH
GRADUALLY PUSHES EAST OF THE AREA. THEN MODELS SUPPORT ADDITIONAL
WEAKER FRONTS AND DISTURBANCES MOVING INTO THE AREA WEDNESDAY
THROUGH LATE NEXT WEEK. -CC
AVIATION...24/18Z TAFS
LOW CLOUDS AND FOG ARE BEGINNING TO
DISSIPATE OVER WEST SIDE LOCATIONS AND SHOULD CLEAR TO VFR OVER THE
NEXT HOUR AND THEN REMAIN SO THROUGH EARLY TONIGHT. PATCHY VALLEY
LIFR (CEILING AND VIS) MAY RETURN TO WEST SIDE LOCATIONS AGAIN
TONIGHT WITH THE HIGHEST PROBABILITY BEING IN THE UMPQUA BASIN
(INCLUDING KRBG). ELSEWHERE, VFR CONTINUES THROUGH TONIGHT. -WRIGHT
MARINE...UPDATED 300 AM PDT THURSDAY, OCTOBER 24, 2024
THE MARINE
FORECAST LOOKS ON TRACK, SO ONLY MINOR UPDATES TO THE FORECAST WERE
MADE TODAY. THE THERMAL TROUGH REMAINS ALONG THE COAST AND CONTINUES
TO PRODUCE NORTH WINDS AND STEEP, WIND DRIVEN SEAS OVER THE AREA
WITH THE MOST HAZARDOUS CONDITIONS SOUTH OF CAPE BLANCO AND BEYOND
10 NM FROM SHORE. THE THERMAL TROUGH WILL GRADUALLY WEAKEN THROUGH
TONIGHT AND THEN DISSIPATE ALTOGETHER FRIDAY MORNING.
WINDS SWITCH TO SOUTH AND INCREASE FAIRLY QUICKLY THROUGH THE DAY
FRIDAY AS A FRONTAL SYSTEM APPROACHES. BY AFTERNOON, WINDS AND SEAS
WILL RISE TO SMALL CRAFT ADVISORY LEVELS OVER MOST OF THE AREA.
CONDITIONS WORSEN AS DEEPENING LOW PRESSURE MOVES BY TO THE WEST AND
NORTH FRIDAY EVENING AND NIGHT WITH SOUTH GALES AND VERY STEEP SEAS
DEVELOPING. THE WORST CONDITIONS WILL BE CLOSEST TO THE LOW PRESSURE
(NORTH OF CAPE BLANCO AND WELL OFFSHORE), BUT ALL AREAS ARE EXPECTED
TO SEE RATHER HAZARDOUS WIND-DRIVEN SEAS AT THE VERY LEAST, AND AS
SUCH, MARINERS ARE URGED TO REMAIN IN PORT. THERE MAY BE ANOTHER
SURGE OF WIND AND HAZARDOUS SEAS AS A SECONDARY LOW PRESSURE SYSTEM
MOVES BY SATURDAY NIGHT INTO SUNDAY, BUT CONFIDENCE IS NOT HIGH
ENOUGH IN THE PLACEMENT NOR STRENGTH OF THIS SYSTEM TO WARRANT ANY
ADDITIONAL HEADLINES AT THIS TIME.
THE PATTERN IS EXPECTED TO REMAIN ACTIVE THROUGH NEXT WEEK AS
ADDITIONAL FRONTS MOVE THROUGH. THIS WILL KEEP CONDITIONS HAZARDOUS
TO SMALL CRAFT (AT A MINIMUM) MUCH OF THE TIME. -WRIGHT
MFR WATCHES/WARNINGS/ADVISORIES
OR...CA...NONE.
PACIFIC COASTAL WATERS...SMALL CRAFT ADVISORY FROM 2 PM TO 8 PM PDT
FRIDAY FOR PZZ350-356-370-376.
HAZARDOUS SEAS WARNING FROM 8 PM FRIDAY TO 5 AM PDT SATURDAY FOR
PZZ350-356-376.
GALE WARNING FROM 8 PM FRIDAY TO 5 AM PDT SATURDAY FOR PZZ370.
SMALL CRAFT ADVISORY UNTIL 2 AM PDT FRIDAY FOR PZZ376.
TAD/CC/TRW
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