Area Forecast Discussion
FXUS66 KMTR [Monterey CA] 240951 AFDMTR ∨
FXUS66 KMTR 240951 AFDMTR [HEAD]
National Weather Service San Francisco Bay Area 2:51am PDT Fri Mar 24 2017 ∨
AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE SAN FRANCISCO BAY AREA 251 AM PDT FRI MAR 24 2017 [HEAD]
Rain and gusty southerly winds return today. ∨
...RAIN AND GUSTY SOUTHERLY WINDS RETURN TODAY... [DISC]
Synopsis. Rain and wind will spread southward today across the forecast area as a cold front moves across the region. A break in the rain is expected Saturday with showers anticipated to return Sunday afternoon and night as a low pressure system moves through. ∨
.SYNOPSIS...RAIN AND WIND WILL SPREAD SOUTHWARD TODAY ACROSS THE FORECAST AREA AS A COLD FRONT MOVES ACROSS THE REGION. A BREAK IN THE RAIN IS EXPECTED SATURDAY WITH SHOWERS ANTICIPATED TO RETURN SUNDAY AFTERNOON AND NIGHT AS A LOW PRESSURE SYSTEM MOVES THROUGH. [DISC]
Discussion. As of 2:51am PDT Friday… the approaching system is taking its time reaching us, but KMUX [Santa Clara/88D CA] radar is starting to fill in with stronger reflectivities off the coast. So far, only a couple hundredths of an inch have been picked up by rain gauges in the North Bay. ∨
.DISCUSSION...AS OF 2:51 AM PDT FRIDAY...THE APPROACHING SYSTEM IS TAKING ITS TIME REACHING US, BUT KMUX RADAR IS STARTING TO FILL IN WITH STRONGER REFLECTIVITIES OFF THE COAST. SO FAR, ONLY A COUPLE HUNDREDTHS OF AN INCH HAVE BEEN PICKED UP BY RAIN GAUGES IN THE NORTH BAY. [DISC]
Latest model runs indicate a slightly slower solution with the main rain band intensifying over the North Bay after sunrise, then spreading south through the remainder of the Bay Area during the morning. The HRRR keeps the Monterey Peninsula rain-free until early afternoon. Satellite-estimated precipitable water values still exceed 180–200% of normal offshore, with over 1.5" of PW [precipitable water] in the moisture plume aimed currently aimed at the Northern California coast. Thus, once this system moves through, episodes of locally heavy rain are possible, especially over coastal hills. Rainfall totals through Saturday morning are forecast to range from 1–3" in the North Bay and coastal hills and from 0.25–0.75" in the lower elevations. Rain to turn to showers this afternoon and end overnight. ∨
LATEST MODEL RUNS INDICATE A SLIGHTLY SLOWER SOLUTION WITH THE MAIN RAIN BAND INTENSIFYING OVER THE NORTH BAY AFTER SUNRISE, THEN SPREADING SOUTH THROUGH THE REMAINDER OF THE BAY AREA DURING THE MORNING. THE HRRR KEEPS THE MONTEREY PENINSULA RAIN-FREE UNTIL EARLY AFTERNOON. SATELLITE-ESTIMATED PRECIPITABLE WATER VALUES STILL EXCEED 180-200% OF NORMAL OFFSHORE, WITH OVER 1.5" OF PW IN THE MOISTURE PLUME AIMED CURRENTLY AIMED AT THE NORTHERN CALIFORNIA COAST. THUS, ONCE THIS SYSTEM MOVES THROUGH, EPISODES OF LOCALLY HEAVY RAIN ARE POSSIBLE, ESPECIALLY OVER COASTAL HILLS. RAINFALL TOTALS THROUGH SATURDAY MORNING ARE FORECAST TO RANGE FROM 1-3" IN THE NORTH BAY AND COASTAL HILLS AND FROM 0.25-0.75" IN THE LOWER ELEVATIONS. RAIN TO TURN TO SHOWERS THIS AFTERNOON AND END OVERNIGHT. [DISC]
In addition to rain, southerly winds are expected to ramp up in advance of and with the front. Winds will be strongest over the higher terrain from Santa Cruz County northward, as well as some coastal areas. A Wind Advisory will be issued for these areas for much of today. Downed limbs, trees and power lines seem likely. ∨
IN ADDITION TO RAIN, SOUTHERLY WINDS ARE EXPECTED TO RAMP UP IN ADVANCE OF AND WITH THE FRONT. WINDS WILL BE STRONGEST OVER THE HIGHER TERRAIN FROM SANTA CRUZ COUNTY NORTHWARD, AS WELL AS SOME COASTAL AREAS. A WIND ADVISORY WILL BE ISSUED FOR THESE AREAS FOR MUCH OF TODAY. DOWNED LIMBS, TREES AND POWER LINES SEEM LIKELY. [DISC]
Precipitation will turn showery by Friday night and end in the pre-dawn hours of Saturday. Saturday looks dry but seasonably cool. ∨
PRECIP WILL TURN SHOWERY BY FRIDAY NIGHT AND END IN THE PRE-DAWN HOURS OF SATURDAY. SATURDAY LOOKS DRY BUT SEASONABLY COOL. [DISC]
Another system will bring rain chances back to the area late Sunday. This system does not look to be as wet, but an additional 0.25–0.50" with local amounts 0.75 inches possible. This rain is expected to be east of the area by midday Monday. Beyond that the remainder of next week now looks dry. ∨
ANOTHER SYSTEM WILL BRING RAIN CHANCES BACK TO THE AREA LATE SUNDAY. THIS SYSTEM DOES NOT LOOK TO BE AS WET, BUT AN ADDITIONAL 0.25-0.50" WITH LOCAL AMOUNTS 0.75 INCHES POSSIBLE. THIS RAIN IS EXPECTED TO BE EAST OF THE AREA BY MIDDAY MONDAY. BEYOND THAT THE REMAINDER OF NEXT WEEK NOW LOOKS DRY. [DISC]
Aviation. As of 10:40pm PDT Thursday… for 06Z [11pm PDT] TAFs [Terminal Aerodrome Forecasts]. VFR [Visual Flight Rules] conditions are expected to persist the next several hours across the Bay Area through about 10 to 14Z [7am PDT] before showers associated with an approaching front push onshore. Rain is expected to reach the San Francisco Bay Area terminals by Thursday morning with a steady rain mid/late morning that will continue into the afternoon and evening hours. Expect ceilings to become MVFR [Marginal Visual Flight Rules] as the rain reaches the terminals. Medium confidence on timing of the rain. ∨
.AVIATION...AS OF 10:40 PM PDT THURSDAY...FOR 06Z TAFS. VFR CONDITIONS ARE EXPECTED TO PERSIST THE NEXT SEVERAL HOURS ACROSS THE BAY AREA THROUGH ABOUT 10 TO 14Z BEFORE SHOWERS ASSOCIATED WITH AN APPROACHING FRONT PUSH ONSHORE. RAIN IS EXPECTED TO REACH THE SAN FRANCISCO BAY AREA TERMINALS BY THURSDAY MORNING WITH A STEADY RAIN MID/LATE MORNING THAT WILL CONTINUE INTO THE AFTERNOON AND EVENING HOURS. EXPECT CEILINGS TO BECOME MVFR AS THE RAIN REACHES THE TERMINALS. MEDIUM CONFIDENCE ON TIMING OF THE RAIN. [AVIA]
Winds are becoming southerly tonight and can expect breezy conditions by mid morning at many locations. Gusts are likely to exceed 20–25 kt [23–29 mph] by 18Z [11am PDT]. High confidence on wind direction, medium confidence on the timing and gust magnitude. ∨
WINDS ARE BECOMING SOUTHERLY TONIGHT AND CAN EXPECT BREEZY CONDITIONS BY MID MORNING AT MANY LOCATIONS. GUSTS ARE LIKELY TO EXCEED 20 TO 25 KT BY 18Z. HIGH CONFIDENCE ON WIND DIRECTION, MEDIUM CONFIDENCE ON THE TIMING AND GUST MAGNITUDE. [AVI2]
Vicinity of KSFO [San Francisco CA]… VFR [Visual Flight Rules] through about 9 to 10Z [3am PDT], and then transitioning to MVFR [Marginal Visual Flight Rules] ceilings and with rain by Friday morning. Southerly winds will increase by morning with gusts exceeding 20 kt [23 mph] by 18Z [11am PDT] and continuing into the afternoon and evening. ∨
VICINITY OF KSFO...VFR THROUGH ABOUT 9 TO 10Z, AND THEN TRANSITIONING TO MVFR CEILINGS AND WITH RAIN BY FRIDAY MORNING. SOUTHERLY WINDS WILL INCREASE BY MORNING WITH GUSTS EXCEEDING 20 KT BY 18Z AND CONTINUING INTO THE AFTERNOON AND EVENING. [AVI2]
SFO [San Francisco CA] bridge approach… same as KSFO [San Francisco CA]. ∨
SFO BRIDGE APPROACH...SAME AS KSFO. [AVI2]
Monterey Bay terminals… VFR [Visual Flight Rules] overnight with generally light winds. Rain showers are expected to begin impacting after 18Z [11am PDT] with MVFR [Marginal Visual Flight Rules] ceilings and increasing southerly winds. ∨
MONTEREY BAY TERMINALS...VFR OVERNIGHT WITH GENERALLY LIGHT WINDS. RAIN SHOWERS ARE EXPECTED TO BEGIN IMPACTING AFTER 18Z WITH MVFR CEILINGS AND INCREASING SOUTHERLY WINDS. [AVI2]
Marine. As of 2:21am PDT Friday… occasional gale force gusts are possible through the day as a storm system impacts the region with strong southerly winds and rain. Seas will be rough with the frontal passage, but should begin to decrease by this evening. Expect northwest winds to return by Saturday morning before briefly becoming southerly on Sunday as another weak system moves over the waters. ∨
.MARINE...AS OF 2:21 AM PDT FRIDAY...OCCASIONAL GALE FORCE GUSTS ARE POSSIBLE THROUGH THE DAY AS A STORM SYSTEM IMPACTS THE REGION WITH STRONG SOUTHERLY WINDS AND RAIN. SEAS WILL BE ROUGH WITH THE FRONTAL PASSAGE, BUT SHOULD BEGIN TO DECREASE BY THIS EVENING. EXPECT NORTHWEST WINDS TO RETURN BY SATURDAY MORNING BEFORE BRIEFLY BECOMING SOUTHERLY ON SUNDAY AS ANOTHER WEAK SYSTEM MOVES OVER THE WATERS. [AVIA]
.MTR WATCHES/WARNINGS/ADVISORIES... .TDAY...WIND ADVISORY...NORTH BAY MOUNTAINS FROM 6 AM THIS MORNING TO 3 PM PDT THIS AFTERNOON WIND ADVISORY...SAN FRANCISCO PENINSULA COAST-EAST BAY HILLS AND THE DIABLO RANGE-SANTA CRUZ MOUNTAINS FROM 10 AM THIS MORNING TO 7 PM PDT THIS EVENING SCA...PIGEON PT TO PT PINOS 0-10 NM SCA...PT PINOS TO PT PIEDRAS BLANCAS 0-10 NM SCA...PT ARENA TO PIGEON PT 10-60 NM UNTIL 9 AM SCA...PT REYES TO PIGEON PT 0-10 NM SCA...PIGEON PT TO PT PIEDRAS BLANCAS 10-60 NM SCA...PT ARENA TO PT REYES 0-10 NM UNTIL 3 PM SCA...MRY BAY FROM 9 AM SCA...SF BAY [WARN]
Public Forecast: Sims; Aviation: Rowe; Marine: BAM ∨
PUBLIC FORECAST: SIMS AVIATION: ROWE MARINE: BAM [CRED]
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24 Mar 2:35am PDT
Overnight A 50% chance of rain. Cloudy, with a low around 50°. Breezy, with a SSE wind around 23 mph, with gusts as high as 29 mph. New precipitation amounts of less than a tenth of an inch possible.
Friday Rain. High near 63°. Windy, with a SSE wind 28 to 34 mph, with gusts as high as 44 mph. Chance of precipitation is 100%. New precipitation amounts between three quarters and one inch possible.
Friday Night Rain before 11pm, then a slight chance of showers after 11pm. Low around 49°. Light NNW wind becoming NW 9 to 14 mph in the evening. Chance of precipitation is 80%. New precipitation amounts between a tenth and quarter of an inch possible.
Saturday Mostly sunny, with a high near 62°. NW wind around 14 mph.
Saturday Night Mostly cloudy, with a low around 48°. NW wind 10 to 13 mph.
Sunday A 50% chance of showers. Mostly cloudy, with a high near 62°. New precipitation amounts between a tenth and quarter of an inch possible.
Sunday Night Showers. Low around 49°. Breezy. Chance of precipitation is 80%.
Monday A chance of showers. Partly sunny, with a high near 62°. Breezy.
Monday Night Partly cloudy, with a low around 46°.
Tuesday Mostly sunny, with a high near 63°.
Tuesday Night Partly cloudy, with a low around 49°.
Wednesday Sunny, with a high near 65°.
Wednesday Night Mostly clear, with a low around 48°. Breezy.
Thursday Sunny, with a high near 62°.
A 50 percent chance of rain. Cloudy, with a low around 50. Breezy, with a south southeast wind around 23 mph, with gusts as high as 29 mph. New precipitation amounts of less than a tenth of an inch possible.
Rain. High near 63. Windy, with a south southeast wind 28 to 34 mph, with gusts as high as 44 mph. Chance of precipitation is 100%. New precipitation amounts between three quarters and one inch possible.
Rain before 11pm, then a slight chance of showers after 11pm. Low around 49. Light north northwest wind becoming northwest 9 to 14 mph in the evening. Chance of precipitation is 80%. New precipitation amounts between a tenth and quarter of an inch possible.
Mostly sunny, with a high near 62. Northwest wind around 14 mph.
Mostly cloudy, with a low around 48. Northwest wind 10 to 13 mph.
A 50 percent chance of showers. Mostly cloudy, with a high near 62. New precipitation amounts between a tenth and quarter of an inch possible.
Showers. Low around 49. Breezy. Chance of precipitation is 80%.
A chance of showers. Partly sunny, with a high near 62. Breezy.
Partly cloudy, with a low around 46.
Mostly sunny, with a high near 63.
Partly cloudy, with a low around 49.
Sunny, with a high near 65.
Mostly clear, with a low around 48. Breezy.
Sunny, with a high near 62.