Scientific Forecaster Discussion
fxus66 khnx 241138
Area forecast discussion
National Weather Service San Joaquin Valley - Hanford California
338 am PST Fri Feb 24 2017
freezing temperatures expected across much of the San Joaquin
Valley this morning. Dry conditions will prevail on today. A
couple of weak disturbances will move through this weekend into
early next week with generally light precipitation.
a very cold morning expected around sunrise as the San Joaquin
Valley experiences a freeze. While temperatures are currently
near freezing, will expect overnight lows to bottom out at or
below the freezing mark this morning. Temperatures have been
running some 3 to 6 degrees below this time Thursday morning,
therefore, confidence is high that widespread freezing will be
reached this morning. A freeze warning is currently in effect
through 8 am PST this morning.
Central California remains in a relatively quiet period in between
storms as a cold and stable air-mass continues over the area.
Yet, change is on the way as infrared-satellite imagery and upper air
analysis show the formation of a disturbance off the Washington
state coast. Short range models prog this disturbance to ride
along the coast as it drops toward California. Current timing has
the storm pushing into the district during the late afternoon on
Saturday. While the potential for precipitation exist before
sunset on Saturday, will expect the a higher potential for
precipitation during the early evening.
The orientation of the upper level flow during the approaching
disturbance may not favor significant precipitation during the
storm event. While moisture will be drawn northward as the upper
level low moves inland on Saturday, the negative tilting of the
trof may force the moisture into Southern California with central
California receiving limited moisture. Yet, light precipitation is
expected during the event with the heaviest accumulation on
Sunday. In addition, Sunday will see a second stronger trof (with
good difluent flow over central california) push into the area for
a continuation of precipitation. By Monday, cyclonic flow over
the region will allow for the continuation of unsettled
conditions. In addition, convective parameters show some
instability over the region. Therefore, some showers could linger
over the area on Monday (mainly over the Sierra nevada) with the
region drying on Tuesday.
Longer range models still indicate the possibility of a dry
extended as a ridge pattern settles over the West Coast by mid-
week. Models confidence is not high, but models are trending
toward a ridge over the west through next weekend. Currently, the
European model (ecmwf) shows a disturbance riding over the ridge next Friday, but,
keeps the main energy well north of the district. Therefore,
confidence toward a dry extended forecast is growing and will
therefore maintain that wording for now.
Aviation...local MVFR in mist across the San Joaquin Valley
through 18z today. Otherwise, VFR conditions will prevail across
the central California interior during the next 24 hours.
Air quality issues...
The level of certainty for days 1 and 2 is high.
The level of certainty for days 3 through 7 is medium.
Certainty levels include low...medium...and high. Please visit
www.Weather.Gov/hnx/certainty.Php for additional information
an/or to provide feedback.
freeze warning until 8 am PST this morning caz089>092.