Area Forecast Discussion
Issued by NWS Los Angeles, CA
Issued by NWS Los Angeles, CA
Versions:
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
509 FXUS66 KLOX 051141 AFDLOX Area Forecast Discussion...UPDATED National Weather Service Los Angeles/Oxnard CA 441 AM PDT Fri Jul 5 2024 .SYNOPSIS...04/739 PM. A significant heatwave will affect the region this week and will continue through much of next week, with dangerously hot temperatures across much of the area. High temperatures will reach 95 to 105 degrees in many areas away from the coast, and upwards of 105 to 115 across interior valleys and foothills, including the Antelope Valley. Patchy night to morning dense fog will develop near the coast through at least Friday morning. && .SHORT TERM (TDY-SUN)...05/431 AM. Well, today is the day - the hottest day of the prolonged period of dangerously hot weather. Make sure to limit time outdoors in the sun and stay hydrated to avoid any heat illness. Some low clouds and fog were hanging out along the coasts early this morning, though very patchy in nature. Onshore pressure gradients between KLAX and KDAG were weakening, while N-S gradients were becoming increasingly offshore. Therefore, the marine layer clouds are expected to burn off rather quickly this morning. Temps at 950 mb are expected to rise quite a bit today due to all of this. This will allow for plenty of heating -up to 20 degrees compared to yesterday`s high temperatures, and 15 to 20 degrees above normal for this time of year. As a result, today has the best chance for several locations to break daily high temperature records. Saturday`s maximum temperatures will be similar to today`s, though a few degrees cooler at the coasts and coastal valleys due to increasing onshore trends through the weekend. Exact temperatures at the coastal locations on Saturday will depend on when the increasing onshore trends start up, leading to less confidence in the heat advisories for coastal areas on Saturday. Even less confidence in the advisories on Sunday as temperatures in the mid 70s to mid 80s would be below advisory criteria. While the onshore flow will reach interior areas on Sunday, temperatures will still be at or above 110 in the deserts and far interior valleys of SLO County, and above 100 degrees in the warmer locations in the L.A./VTU valleys. Therefore the Excessive heat warnings will likely still be needed across those locations. The increase in onshore winds there in the afternoon, particularly across the interior mountains and Antelope Valley, will increase the fire risk in those areas. .LONG TERM (MON-THU)...05/440 AM. Unsurprisingly, hot weather continues through the extended period due to the high pressure aloft hanging out to the north and east of the region. The onshore flow starts weakening again on Monday resulting in a few degrees of warming both Monday and Tuesday across the region, except the deserts and mountains which will change little if at all due to the stationary high. Then, conditions are expected to be very similar Tuesday through Thursday. The deserts and far interior areas of SLO County will continue to scorch with highs near or above 110 and warmer coastal valley highs will reach around 105 each day. Lower confidence with coastal temperatures due to the uncertainty with the marine layer and possible eddy development over the southern coastal waters, but highs there should be up to 4-8 degrees above normal all week. && .AVIATION...05/0207Z. At 00Z at KLAX, the marine layer was 800 feet deep. The top of the inversion was at 4000 feet with a temperature of 31 deg Celsius. High confidence in CAVU TAFs for KPRB, KBUR, KVNY, KPMD, and KWJF. Expect somewhat less low cloud coverage tonight, mainly affecting coastal sections of L.A. and VTU Counties, and possibly the Central Coast. Most likely cigs will be IFR/LIFR. There is a 40% chance of VLIFR at coastal sites late tonight and early Fri. From 04Z-09Z this evening, there may be areas of MVFR vsbys due to smoke and haze from holiday fireworks celebrations. KLAX...Moderate confidence in the 00Z TAF. Cigs may arrive as early as 03Z, and as late as 09Z. There is a 50% chance of VLIFR conds 09Z-14Z Fri. KBUR...High confidence in the 00Z TAF with VFR conds thru the period, except there is a 30% chance of MVFR vsbys due to smoke and haze from 05Z-09Z. && .MARINE...05/423 AM. In the Outer Waters, Small Craft Advisory (SCA) level winds will continue in the southern zones (PZZ673/PZZ676) thru Sat morning. In the northern zone (PZZ670), SCA conds are likely (70% chance) this afternoon thru tonight. For the most part, expect winds to remain below SCA levels Sat afternoon thru Tue night. However, there is a 30% chance of SCA level NW winds in the far outer waters and from near Pt. Conception to NW of San Nicolas Island, especially during the late afternoon thru late evening hours. For the Inner Waters N of Pt. Sal, SCA conds are likely (70% chance) this afternoon/eve. There is a 30% chance of SCA level winds Sat afternoon/eve. SCA conds are not expected Sat night thru Tue night. For the Inner Waters south of Pt. Conception, there is a 40% chance of SCA conds late this afternoon and evening in western portions of the Santa Barbara Channel, mainly from Santa Cruz Island to the SBA County south coast from Pt. Conception to Gaviota to Refugio State Beach. Otherwise, conds will be below SCA levels for the southern inner waters thru Tue night. Areas of dense fog will affect the coastal waters this morning. Please reference the Marine Weather Statement for additional information. && .LOX WATCHES/WARNINGS/ADVISORIES... CA...Excessive Heat Warning remains in effect until 6 PM PDT Wednesday for zones 38-343>345-353-376>379-381>383. (See LAXNPWLOX). Excessive Heat Warning remains in effect until 6 PM PDT Monday for zones 88-342-348-351-352-356>358-369>375-380. (See LAXNPWLOX). Heat Advisory remains in effect until 6 PM PDT Sunday for zones 341-347-355-368-548. (See LAXNPWLOX). Excessive Heat Warning remains in effect until 6 PM PDT Saturday for zones 349-350. (See LAXNPWLOX). Wind Advisory in effect until 5 AM PDT early this morning for zones 349-351. (See LAXNPWLOX). Beach Hazards Statement in effect through Sunday evening for zones 354-362-366. (See LAXCFWLOX). Red Flag Warning in effect from 10 AM this morning to 6 AM PDT Saturday for zones 342>345. (See LAXRFWLOX). Red Flag Warning in effect until 6 AM PDT Saturday for zones 349-351>353-376>378-381. (See LAXRFWLOX). PZ...Small Craft Advisory in effect from 3 PM this afternoon to 9 PM PDT this evening for zone 645. (See LAXMWWLOX). Small Craft Advisory in effect from 3 PM this afternoon to 3 AM PDT Saturday for zone 670. (See LAXMWWLOX). Small Craft Advisory in effect until 9 AM PDT Saturday for zones 673-676. (See LAXMWWLOX). && $$ PUBLIC...Lund/DB AVIATION...Phillips/Sirard MARINE...DB SYNOPSIS...MW/KL/CS weather.gov/losangeles Experimental Graphical Hazardous Weather Outlook at: https://www.weather.gov/erh/ghwo?wfo=lox