Warm/dry conditions continue thru the weekend as a weak High Pressure ridge builds into the region with temps reaching 10° to 15° above average on Sunday. A storm system passing thru NORCAL late Sun into Mon will bring gusty winds to the Westside SJV and Kern Co Mts, with a slight chance of showers reaching as far south as Fresno on Monday with winds continuing into Monday evening. High Pressure rapidly returns on Tuesday with decreasing clouds and warming temps as an offshore flow pattern develops. Temps by next weekend could see widespread 80°’s in the SJV. With regards to rainfall, the 16 Day Forecast offers little if any precip for CENCAL, except what may fall in the northern districts on Monday, otherwise dry thru most of the Fantasyland period ending Mon, Mar 24th. Day 16 shows some possible rainfall with a low confidence level. The High Pressure remains dominant over CA thru approximately Thu, Mar 20th when the ridge retrogrades westward and pushes northward into Alaska. What happens after that is in a constant state of flux with each model run, however it still offers the potential for cold air arriving into CA. Timing, strength and positional details are still in high degree fluctuation as to the extent which the downwind flank of the ridge produces an ARCTIC cold trough which carves out somewhere near the PACNW …with destination unknown at this time. Needless to say that temps will be significantly lower.
Precip Totals past 24hrs include; 2.04 Elk Valley, 2.00 Gasquet, 1.25 Hoopa, 1.22 Somes Bar, 0.96 Orick, 0.93 Big Hill, 0.85 Sawyers Bar, 0.84 Taylor Ridge, 0.68 Arcata, 0.61 Mud Springs, 0.56 Ruth Lake, 0.36 Friend Mtn, 0.33 Hayfork, 0.28 Trinity, Hoadley, 0.24 Honeydew, 0.20 Bridgeville, Hirz, Brandy Crk, Lakeshore, 0.12 Shasta Dam, 0.09 Redding, 0.08 Four Trees, 0.05 Lassen, Quincy, Willits, 0.03 De Sabla, Bucks Crk, La Porte, 0.02 Corning, Mt Shasta City, 0.01 Chico, Red Bluff, Cohasset, Oroville
FORECAST SUMMARIES
Days 1-7;
Sun, Mar 9th While 570dm High Pressure covers most of CA, a moist SW flow pattern continues to advect a long-fetched Atmospheric River (AR) into the PACNW and the far NW portion of NORCAL. Overnight a shortwave trough pushes the rapidly diminishing AR southward into CENCAL with possible showers as far south as Monterey to Madera Co and then as far south as the San Joaquin River basin in the Sierra.
Mon, Mar 10th Lingering showers in the morning for the northern districts dissipate by afternoon with clearing skies as the broad West Coast ridge intensifies and shunts the storm track northward into BC, Canada, as an extended dry period for CA begins with above normal temps. Overnight the ridge axis moves onshore over the West Coast.
Tue, Mar 11th High Pressure offshore the West Coast intensifies up into WA, with fair skies and slightly cooler temps over CA. Overnight the strong RRR High Pressure ridge shifts onshore and pushes further into the PACNW.
Wed, Mar 12th The 570dm High Pressure over CA flattens as a minor disturbance moves into WA, with fair/mild conditions prevailing over CA.
Thu, Mar 13th The West Coast ridge is dominant over the West Coast as the storm track is diverted north into BC, Canada. While heavy rains fall into the Vancouver, BC region, CA remains fair/mild.
Fri, Mar 14th The High Pressure ridge intensifies over the West Coast, with fair/mild conditions continuing over CA with a warming trend.
Sat, Mar 15th The RRR High Pressure ridge intensifies to a 582dm circulation near SOCAL, with rapidly rising temps reaching into the 80°’s for the lowlands in CENCAL. Overnight the 582dm High Pressure cell moves onshore over CENCAL.
Days 8-16, Long Range into Fantasyland Outlook; Day 8 begins;
Sun, Mar 16th shows unusually strong 582dm High Pressure covering CEN/SOCAL with fair skies and very warm temps into the 80°’s. Overnight a weak shortwave trough slides eastward thru the PACNW coastline.
Mon, Mar 17th shows the High Pressure ridge weakening slightly with a fair/warm day for CA.
Tue, Mar 18th shows the top of the High Pressure ridge flattening as a moist disturbance moves into BC, Canada. CA may have an offshore flow pattern with continued fair/warm conditions.
Wed, Mar 19th shows the RRR High Pressure ridge shifting west, with a developing NW flow pattern for CA bringing temps back down a bit from the previous warm days. The first of several upcoming cold troughs from the north slides into the PACNW on a SE trajectory and heads into ID. Overnight the High Pressure ridge shifts west, with the axis now near 160W.
Thu, Mar 20th shows a second cold trough pushing SE thru the PACNW as the High Pressure offshore places CENCAL into an onshore westerly flow pattern. Conditions over CA remain fair
Fri, Mar 21st shows strong High Pressure over Alaska steepening up into the ARCTIC region with the downwind flank sending ARCTIC air southward thru the Yukon to offshore BC, Canada with a developing cold trough near Vancouver, BC.
Sat, Mar 22nd shows the High Pressure over Alaska tilts into the Yukon, with a large trough carving out over SW Canada with an ARCTIC -36°C cold core centered over BC, Canada which is retrograding SW to offshore WA. As the system moves offshore over water, it picks up moisture which then flows into OR. The pattern begins to influence NORCAL with an onshore flow. Overnight the very cold trough intensifies to a 528dm Low Pressure storm center, which continues to sag southward as winds aloft over NORCAL veer to the SW. Charts also show a small disturbance possibly moving into SOCAL, lacking any moisture.
Sun, Mar 23rd shows a powerful winter storm offshore west of the Columbia River, with a cold core temp of -36°C. The system is making a progressively longer trajectory over water, so this once moisture starved storm continues to gain a moisture supply. In addition a slug of subtropical moisture is moving northward toward the CA coast. Overnight the two features fuse together over NORCAL, with heavy rains.
Mon, Mar 24th shows a robust cold front moving thru CA which is supplied by the rich moisture source from the subtropics. Rains spread throughout the State, while the large Low Pressure circulation migrates into the GOA. High Pressure has shifted to near the Dateline leaving the EPAC in a large cyclonic flow.
NEW RECORDS
Station New Record Old Record__
Lancaster 50° (Ties) 50° High Min
Palmdale 51° (Ties) 51° High Min
Santa Barbara 55° (Ties) 55° High Min
Paso Robles 52° 51° set in 1957 High Min
Riverside 61° 54° set in 1989 High Min
Big Bear 36° (Ties) 36° set in 1982 High Min
Palm Springs 65° 63° set in 2004 High Min
Las Vegas 75° (Ties) 75° set in 2007 High Min
PRECIPITATION FORECAST
Day 1 – 5 QPF:
At 12Z (9am) Saturday thru the period Wednesday night (Thursday @4am);
7 Day QPF Chart; showing up to 4.2 inches near Crescent City with diminishing amts further south with up to 3-4 inches along the far NW Coastal region. With up to 2-3 inches from Fort Bragg to the Shasta River basin, then SE thru the Northern Sierra with a 3.2 inch focal point placed into the Feather River basin. Up to 1-2 inches is forecast from near the Russian River to the northern SAC Valley, then SE thru the Sierra to near the I-80 corridor. With up to 0.5 to 1 inch from Santa Rosa to Chico then SE thru the Sierra to near Hwy 50, with 0.25 to 0.5 inch from the North Bay region to near SAC then SE thru the Sierra to near the Stanislaus River basin, with up to 0.25 inch from the Santa Cruz Mts and Bay region eastward to near YNP. Trace amts up to 0.1 inch are depicted from near Monterey east to Kings Cyn.
16-Day QPF estimates (from the 0Z GFS model) for;
Days 1-7; shows up to 4.2 inches near Crescent City with diminishing amts further south with up to 3-4 inches along the far NW Coastal region. With up to 2-3 inches from Fort Bragg to the Shasta River basin, then SE thru the Northern Sierra with a 3.2 inch focal point placed into the Feather River basin. Up to 1-2 inches is forecast from near the Russian River to the northern SAC Valley, then SE thru the Sierra to near the I-80 corridor. With up to 0.5 to 1 inch from Santa Rosa to Chico then SE thru the Sierra to near Hwy 50, with 0.25 to 0.5 inch from the North Bay region to near SAC then SE thru the Sierra to near the Stanislaus River basin, with up to 0.25 inch from the Santa Cruz Mts and Bay region eastward to near YNP. Trace amts up to 0.1 inch are depicted from near Monterey east to Kings Cyn.
Days 8-16; shows up to 0.5 inch for the NW Coastal region, with up to 0.20 inch down to SAC and Tahoe, dropping to >0.1 inch for CENCAL and none for SOCAL.
GFS 384hr, 16Day QPF Chart, depicting a wet NORCAL, with lighter amts suggest for CENCAL.
SATELLITE
Water Vapor 4KM Image of the West Coast Saturday, March 8th, 2014, shows an Atmospheric River of subtropical moisture flowing NE into southern BC, Canada and the PACNW down into NORCAL, with high clouds over CENCAL.
Visible Satellite Image of the CA Saturday, March 8th , 2014, shows cloudiness spreading over portions of NORCAL, with some high cloudiness over CENCAL.
If you have any questions please call or text at any time of day or night.
Comments and suggestions always welcome.
Atmospherics Group International
Dan Gudgel Steve Johnson
559-696-9697 559-433-7316