Update - Heat Wave This Weekend - Then Colder, and Maybe Wet!

Update

CA HEAT WAVE this weekend Mar 15^th and 16^th with Record-Setting High Temps possible, then turning colder and possibly wet, Thu/Fri Mar 20^th/21^st with chance of frostto follow the storm departure.

By the way, Sunday the SJV had its first 90° temp! Recorded at the Comanche Ag Station south of Edison and east of the Grapevine.

The EPAC transforms into a highly amplified pattern during the next 16 Day period with the return of the infamous RRR High Pressure ridge forecast to produce possible record setting heat this weekend, followed by a -32° cold core storm which we have been discussing for some time. Forecast charts today are trending warmer regarding this upcoming weekend time period, Mar 15^th and 16^th, so much so that temps may reach into Record-Setting territory. Tonight’s 0Z GFS charts show a 587dm High Pressure cell south of Pt Conception and west of San Diego on Sunday with 582dm heights reaching across most of CA. (See charts below ↓) The unusual strength of the ridge for the month of March is somewhat reminiscent of the same ridge configuration experienced during Dec 2013 and Jan 2014. The Penn State Historical Record Web Site places this event as +2.5 anomaly, with possible records for the NOR/CENCAL region.

The other primary focus is how the GFS model is evolving the forecasted cold event, which has been on the charts for quite some time but has shifted far out to sea with a large water trajectory. A few days ago this cold storm was projected to drop southward from the Yukon, with no water trajectory and now it is dropping southward much farther west with a larger water trajectory. This is much better news for CA as it lessens the potential for FROST and increases the possibility of beneficial precip spreading across the region. This event is still evolving and has lots of time left to continue changing, so hold on to your hats, it is definitely not finished baffling us. However the trending theme continues to suggest a cold eventof one form or another reaching the West Coast around Mar 21^st, with unknown details as to how cold, or how wet, etc. The GFS also showing a second cold storm arriving at the end of the Fantasyland forecast on Tue, Mar 25^th.

We’ll see what tomorrow brings, in the meantime prepare for the heat this weekend.

HEATWAVE

GFS 500mb Charts showing the RRR High Pressure ridge building back over CA on Saturday, producing a downsloping offshore flow pattern over CEN/SOCAL.

GFS 500mb Charts showing the RRR High Pressure ridge over CA on Sunday, producing a downsloping offshore flow pattern over SOCAL. With the 588dm heights close to shore on Sunday, record-setting temps are possible for CA.

Station Previous Record Sat Previous Record Sun

Fresno 87° 88°

Bakersfield 94° 91°

Hanford 81° 89°

Madera 80° 88°

Merced 79° 85°

COLD EVENT

In stark contrast to the Record Setting High Pressure ridge on Mar 15^th and 16^th, here is a current look at the GFS solution of the cold event forecast to begin on Thu, Mar 20^th, showing a 538dm Low Pressure -32°C cold core circulation west of the OR coastline, with increasing SW flow reaching into CA. This storm exits the region on the 22^nd with a chance of FROST in the SJV if skies are clear.

A second colder storm is forecast to drop south from the GOA on Day 15/16, Mar 24^th and 25^th, this chart is the end of the Fantasyland realm …of course with a low confidence level.