Scientific Forecaster Discussion
Area forecast discussion
National Weather Service San Joaquin Valley - Hanford California
315 am PDT Thursday Jul 30 2015
a northwestward influx of monsoonal moisture will bring an increase
in clouds and humidity to the central California interior through
Friday with a chance of thunderstorms...especially over the
mountains and desert.
monsoonal moisture had begun pushing northward into Southern
California Wednesday evening...with thunderstorms as far north as
northwestern San Bernardino...southern Inyo and northern Los
Angeles counties. The latest GOES infra-red loop shows middle and high
clouds over Kern County...so keeping a mention of thunderstorms for
the Kern County mountains and desert looks on track.
There will be two major weather concerns today...both due to
thunderstorms. The first concern is dry lightning that could result
in additional wildfire starts. The lower levels of the atmosphere
were dry this morning. At 09z /0200 PDT/...the relative humidity at
Bakersfield was 10 percent...and at Avenal 14 percent...both drier
than the Kern County desert. In the piutes...humidities were only in
the 20/S. Until the lowest levels moisten...any rain that falls
initially will evaporate on the way down.
The second concern is the potential for flash flooding in the Kern
County mountains and deserts this afternoon. Once there is enough
low-level moisture for rain to reach the ground...runoff from slow-
moving thunderstorms could cause rises in creeks and streams...mud
or debris flows and Road erosion...especially in the Kern desert
near the El Paso Mountains...a flood-prone area. A Flash Flood Watch
has been issued for the Kern County mountains and deserts for late
this morning through early this evening.
High temperatures in the central and southern San Joaquin Valley
were solidly in triple digits Wednesday...with Fresno reaching 108
degrees and Bakersfield a degree lower. The increasing cloud cover
will keep highs a little cooler today...but triple digit highs will
continue for the rest of the week.
The 06z NAM-12 has no precipitation for the San Joaquin Valley from
this monsoonal surge...and the 03z sref does have rain over the
southern San Joaquin Valley for this afternoon and evening...but is
dry north of Visalia or Hanford. Even the 29/15z rfc quantitative precipitation forecast guidance
has 0 quantitative precipitation forecast for Fresno...with the heaviest quantitative precipitation forecast over the southern part
of the Sierra Nevada near Giant Forest and Rogers Camp.
The models continue to forecast the flow aloft to turn southwesterly
Sunday...bringing a drying trend to the region. As a result...
expect that any convection next week would be confined to the high
country of the southern Sierra Nevada.
isolated thunderstorms in the mountains and desert areas of Kern
County after 18z today. Thunderstorms spreading northward along the
Sierra Nevada after 22z today. Otherwise VFR conditions can be
expected throughout the central California interior during the next 24
Air quality issues...
on Thursday July 30 2015... unhealthy in Madera County. Unhealthy
for sensitive groups in Fresno... Kern... Kings... Merced and
Tulare counties and Sequoia National Park and Forest.
Further information is available at valleyair.Org
The level of certainty for days 1 and 2 is high.
The level of certainty for days 3 through 7 is high.
This information is provided as part of a trial project conducted
by the National Weather Service San Joaquin Valley - Hanford.
Certainty levels include low...medium...and high. Please visit
www.Weather.Gov/hnx/certainty.Php /all lower case/ for additional
information and/or to provide feedback.
site date hi_max:year lo_max:year hi_min:year lo_min:year
Kfat 07-30 114:1898 80:1966 83:2003 57:1975
kfat 07-31 114:1908 83:1976 81:1908 53:1895
kfat 08-01 112:1908 79:1933 86:1908 56:1888
Kbfl 07-30 112:1908 82:1965 82:2014 48:1914
kbfl 07-31 110:1943 85:1985 81:2014 55:1905
kbfl 08-01 112:1979 86:1985 80:2000 53:1912
Flash Flood Watch from 11 am PDT this morning through this
evening for the Kern County mountains...Indian Wells Valley and
the southeastern Kern County desert /caz095-098-099/.