904
FXUS66 KHNX 180939
AFDHNX

Area Forecast Discussion
National Weather Service Hanford CA
239 AM PDT Tue Jun 18 2024

&&

.KEY MESSAGES...

1. A Red Flag Warning remains in effect for strong gusty winds
coupled with low relative humidity that will bring Elevated Fire
Weather concerns to the Kern County mountains, West Hills and
the San Joaquin Valley through noon.

2. Snowmelt from the higher elevations of the Sierra Nevada,
will continue to result in dangerously cold and fast flows along
rivers and waterways.

3. Starting Tuesday a warming trend will begin with triple
digits anticipated starting Friday lasting through next weekend.

&&

.DISCUSSION...

A broad upper level trough continues across the west coast of
the CONUS this morning. This trough holds in through Thursday
with gradual weakening as upper height rise. The large ridge
parked over the eastern CONUS begins to back into the region on
Friday. On Saturday the ridge to the east meets the Pacific
ridge to build upper level heights over the Golden State. This
becomes the dominate feature lasting into early next week and
the foreseeable future. 500 MB heights are expected to build
into the low 590s.

The impacts for this morning will be the diminishing wind gusts
along the Mojave Slopes. The High Wind Warning is set to expire
at 5 am and that should hold up. The short range ensembles
support this with probabilities of 60 mph wind at zero percent.
Even wind gusts in excess of 40 mph declines rapidly towards
dawn to less than 20 percent. The other highlight is the Red
Flag Warning across the San Joaquin Valley and Kern County
Mountains. The wind continues to relax throughout the morning.
The short range ensembles show the probability of 25 mph wind
gusts going down and become a zero percent probability by 10 am.
The poor relative humidity recoveries and still a breeze. Have
decided to push the Red Flag Warning out to noon.

Wednesday and Thursday the focus moves away from wind. Humidity
remains low across the region. The temperature returns to the
forefront of the forecast. The probability of exceedance of
normal maximum temperatures (92-93 degrees) ranges from 26 to 61
percent on Wednesday and 56 to 91 percent on Thursday.

The trend moves upward focusing on the PoE of 100 on Friday. The
PoE of 100 degrees remains in the range of 16 to 41 percent.
Zooming on Fresno Air Terminal point the statical spread is
fairly confident on a range of 98 to 101 degrees. Overnight lows
at Fresno 68 to 71 degrees. Confidence is fairly strong across
the San Joaquin valley with similar results. Viewing the Day 4
500 MB cluster analysis the range of possibilities is fairly
tight on the pattern and in reasonable on trend of anomalies in
the heights. The heat risk for excessive heat remains in the
little to none range for Friday.

Saturday turns up the heat on the forecast for the region. The
oddity is the highest height anomaly is centered from Northern
California into Oregon across the spectrum of the cluster.
Central California has a higher than normal anomaly. Still does
not seem to fit a typical heat wave. The EFI is not impressed
with anomaly values. The PoE of 100 degrees is 85 percent to
near 100 in the San Joaquin Valley seems very reasonable. The
PoE of popping 105 degrees ranges 20 to 40 percent north and
foothills, 36 to 56 percent in the heart of the valley.
Saturday`s range of probable maximum temperatures is 104 to 107
and minimums of 73 to 75 at Fresno for the example. Heat risk
has a good swath of level 3 or major risk and fair amount of
moderate risk. The general feeling is that the overnight
minimums are more of the issue than afternoon maximums. Still we
are looking at 8-12 degrees above normal on maxs and mins. NBM
trend has been a tweak down from yesterday. Putting the puzzle
to together with the trend and anomalies will opt to hold the
cards on the excessive heat highlights keeping the focus on fire
weather for today. The main highlight continues to be the cold
water from runoff risk to life. Will keep messaging the cold
water threats.

Sunday into next Tuesday the spread of solutions in the clusters
and point data spreads open quite a bit. The PoE of 100 degrees
continues above 60 percent for the Valley floor. The PoE of 105
is highest in the period on Sunday with the spread 11 to 46
percent. Monday and Tuesday, outside of Fresno, falls below 20
percent with Fresno ranging from 21 to 26 percent. Using the
Fresno example the range opens to 100 to 105 each day and
overnight lows now dropping into the upper 60s. The heat risk
guidance responds with mostly moderate level across the region.

Saturday through next Tuesday looks to be a hot period and
possibly with a reverse in trends then excessive heat risk
advisory/warning would be a probability.

&&

.AVIATION...

VFR conditions will prevail across the Central CA interior for
the next 24 hours. Very localized reduction to visibilities are
probable near any fires.

&&

.FIRE WEATHER...

Poor overnight relative humidity recovery this morning with some
continued breezy conditions mainly along the I-5 has prompted
an extension of the Red Flag warning through noon. Otherwise,
the wind becomes less of an issue by midday and not much concern
for the rest of the week. Relative humidly will continue on the
low side through the foreseeable future during the afternoon.
Overnight recovery does move up above 40 percent helping out
during the nighttime hours. The current pattern is not favorable
for any thunderstorm activity keeping dry lightning threat near
zero.

&&

.AIR QUALITY ISSUES...
ISSUED:  06/17/2024 14:57
EXPIRES: 06/18/2024 23:59
None.

&&

.CERTAINTY...

The level of certainty for days 1 and 2 is medium.
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.html for additional information
and/or to provide feedback.

&&

.HNX WATCHES/WARNINGS/ADVISORIES...
High Wind Warning until 5 AM PDT early this morning for CAZ338.
Red Flag Warning until noon PDT today for CAZ579-580-596-597.
&&

$$

public/aviation/fire weather...Proton
IDSS....DCH

weather.gov/hanford