NWS San Diego, CA wrote its last area forecast discussion before the first event at Jun 19, 8:21 AM PST, 3 hours 39 minutes earlier.
Area forecast discussion, Jun 19, 8:21 AM PST, 3 hours 39 minutes before
AREA FORECAST DISCUSSION
National Weather Service San Diego CA
921 AM PDT SUN JUN 19 2016
.SYNOPSIS...
A high pressure ridge will strengthen through Monday, producing
very hot weather today through Tuesday. High temperatures will be
well above normal, likely breaking several records, with Monday
being the hottest day. Some mid and upper level moisture will
produce numerous high clouds Tuesday. This, in addition to a coastal
eddy, could bring some cooling Tuesday along with a return of
night and morning coastal low clouds and fog. Warmer than normal
conditions for the coast and valleys, and hot conditions in the
deserts, will continue through the end of the work-week as the
ridge lingers over the region.
&&
.DISCUSSION...FOR EXTREME SOUTHWESTERN CALIFORNIA INCLUDING ORANGE...
SAN DIEGO...WESTERN RIVERSIDE AND SOUTHWESTERN SAN BERNARDINO
COUNTIES...
Morning visible satellite indicates clearing mid and high level
clouds, resulting in mostly sunny skies. Water vapor satellite
imagery shows a ridge building near New Mexico and expanding west
into Southern California. The 12Z Miramar sounding shows about 4-6
degrees of warming between the surface and 750 mb compared to
yesterday morning, so the warmer air mass produced by the building
upper level ridge is evident. Excessive Heat Warnings and Heat
Advisories go into effect today as things really start to heat up.
Models show 500 mb heights of 595-596 DM reaching into our region
this afternoon. Highs today are expected to reach 15-20 degrees
above normal, and locally up to 25 degrees above normal. Highs are
forecast to reach the mid to upper 80s at the coast, 95-99 a few
miles inland, 98-105 for the San Diego county valleys, 96-102 for
inland Orange county, 93-102 for the Santa Ana
mountains/foothills, 102-108 for the Inland Empire, 93-104 in the
mountains below 6000 feet, low 90s above 6000 feet, 99-107 in the
High Deserts, and 114-119 in the Lower Deserts.
Monday still looks like it will be the hottest day, with
500 mb heights reaching 597 DM over us (which would be near
record-breaking for June), and 600 DM over the four corners where
the core of the high will be. Models continue to show 850 mb
temperatures of 32-33 deg C over the deserts and near 31 deg C at
the coast. GFS MOS guidance seems to have the best handle on
temperatures, considering how anomalously strong this ridge will
be. It continues to show highs potentially reaching 122 in Palm
Springs, 110 in Ontario, and now up to 110 in Ramona. Right now,
the forecast shows highs reaching 85-90 at the coast, 95-101 at
few miles inland, 100-108 for the San Diego county valleys, 97-107
for inland Orange County, 100-108 for the mountain slopes below
6000 feet, 105-112 in the Inland Empire, 90s at mountain resort
levels, 103-113 in the High Deserts, and 115-121 in the lower
deserts. These temperatures may need to be adjusted upward. This
will result in numerous temperature records being broken or tied
on Sunday and especially Monday. See the CLIMATE section below for
more details.
Should not be quite as hot on Tuesday as the models continue to
show a coastal eddy developing Monday night and continuing through
the day Tuesday. This should bring some cooling to the coast and
valleys. Another factor that will likely produce lower
temperatures on Tuesday is mid and high clouds associated with an
easterly wave which is expected to move over the region. Even
though the ridge weakens only slightly that day, the cloud cover
should reduce temperatures in the mountains and deserts by a few
degrees. Regardless, it will still be quite hot. The coastal eddy
may also bring a return of marine layer low clouds and fog to the
coast as early as Monday night. The majority of moisture
associated with the wave is above 500 mb, with a dry layer below
that level. Elevated instability looks weak at the moment, so
it would likely just produce virga and maybe a few sprinkles.
The ridge will weaken a bit further on Wednesday, producing a bit
more cooling. However, temperatures will still be above normal,
especially in the deserts where it will still be pretty hot. 594
DM 500 mb heights hang around Thursday and Friday as well, so
temperatures well above normal should continue. There's the
possibility that the Excessive Heat Warning for the deserts, which
currently ends Wednesday evening, may need to be extended a day or
two longer. Even by next weekend, the ridge will still be
dominating across the south and southwest U.S., continuing the
warm/hot weather. A shallow marine layer should produce night and
morning marine layer clouds/fog along the coast and western
valleys Wednesday through next weekend, with subtle day-to-day
variations.
&&
.AVIATION...
191530Z...FEW clouds around 20K ft this morning, then becoming
mostly SKC. Temperatures will rise to 115-119 F this afternoon in
portions of the Coachella Valley and Low Desert, and could make take-
off more difficult for heavy aircraft. Mostly P6SM vis through Mon
morning.
&&
.MARINE...
830 AM...NW wind gusts to 20 kt is possible at times over the outer
waters through Monday. Otherwise, no hazardous marine weather is
expected through Thursday.
&&
.CLIMATE...
Many high temperature records will likely be broken or tied through
Monday with some record high minimum temperature records broken or
tied as well. Based on the current forecast...here are some of the
records that could be tied or broken...
For Today...
Forecast Current Record
Newport Beach 83 82 in 1957
Chula Vista 92 88 in 1957*
Escondido 103 102 in 1929
El Cajon 102 94 in 2001
Ramona 105 102 in 2008
Alpine 103 103 in 1973
Big Bear Lake 87 87 in 1985
Idyllwild 94 93 in 1961
Palomar Mountain 93 91 in 1954
Campo 104 104 in 1989
Palm Springs 116 116 in 2008
Borrego Springs 115 115 in 1989
For Monday...
Forecast Current Record
Newport Beach 86 82 in 1929
Chula Vista 92 85 in 2008*
Escondido 108 104 in 1973
El Cajon 105 94 in 2007
Ramona 107 106 in 2008
Idyllwild 95 95 in 2001
Palomar Mountain 96 91 in 1970
Palm Springs 119 118 in 1929
Indio 117 116 in 1929
Thermal 120 118 in 2008
Borrego Springs 116 116 in 2008
* - Ties all-time record for June
For reference, the all-time record highs for June at
certain locations are as follows:
Chula Vista 92 (set in 1990)
Lake Elsinore 114 (set in 1917)
Escondido 109 (set in 1896)
El Cajon 106 (set in 1990)
Ramona 108 (set in 1981)
Alpine 109 (set in 1976)
Idyllwild 99 (set in 2013)
Campo 107 (set in 1994)
Palm Springs 122 (set in 2013)
&&
.SKYWARN...
Skywarn activation will not be needed today.
&&
.SGX Watches/Warnings/Advisories...
CA...Excessive Heat Warning from 11 AM this morning to 8 PM PDT
Wednesday for Apple and Lucerne Valleys-Coachella Valley-
Riverside County Mountains-San Bernardino County Mountains-
San Diego County Deserts-San Diego County Mountains-San
Gorgonio Pass Near Banning.
Excessive Heat Warning from 11 AM this morning to 8 PM PDT
Tuesday for Orange County Inland Areas-San Bernardino and
Riverside County Valleys-The Inland Empire-San Diego County
Valleys-Santa Ana Mountains and Foothills.
Heat Advisory from 11 AM this morning to 8 PM PDT Monday for
Orange County Coastal Areas-San Diego County Coastal Areas.
PZ...None.
&&
PUBLIC...Harrison
CLIMATE...17/Harrison
AVIATION/MARINE/BEACHES...JJT