NWS Area Forecast Discussion
000 FXUS66 KLOX 080523 AAA AFDLOX SOUTHWEST CALIFORNIA AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE LOS ANGELES/OXNARD CA 923 PM PST TUE FEB 7 2012 ...UPDATED AVIATION DISCUSSION... .SYNOPSIS... A STORM SYSTEM WILL CONTINUE TO EXIT THE REGION TONIGHT AND HIGH PRESSURE WILL BUILD IN BEHIND IT. OFFSHORE FLOW ESTABLISHING WILL PRODUCE FAIR AND WARM WEATHER INTO FRIDAY...WITH PERIODS OF GUSTY OFFSHORE WINDS IN SOME LOCATIONS. A WEAK LOW PRESSURE SYSTEM WILL APPROACH THE AREA OVER THE WEEKEND FOR INCREASED CLOUDINESS AND A SLIGHT COOLING TREND INTO EARLY NEXT WEEK. && .UPDATE... MAINLY SHOWERS ARE STREAMING OVER THE AREA THIS EVENING AS THE TROUGH CONTINUE TO GRADUALLY MOVE EAST THROUGHOUT TONIGHT AND INTO WEDNESDAY MORNING. LOW-LEVEL EASTERLY FLOW CONTINUES TO DRY THE LOWER LEVELS REDUCING EVAPORATING PRECIPITATION AS IT IS FALLING. ENOUGH MOISTURE AND INSTABILITY IS PRESENT ALOFT TO WARRANT CHANCES OF SHOWERS FOR NOW OVER COASTAL AND VALLEY LOCATIONS WEST OF THE MOUNTAINS. THE LATEST FOG PRODUCT IMAGERY IS STARTING TO INDICATE THE WRAP- AROUND MOISTURE MOVING INTO THE AREA THIS EVENING. INFRARED IMAGERY SHOWS CLOUD TOPS COOLING TAKING PLACE THIS EVENING AND SHOWERS WILL BECOME MORE WIDESPREAD OVER THE LOS ANGELES COUNTY MOUNTAINS AND THE FOOTHILLS OF THE ANTELOPE VALLEY TONIGHT AS THE MOIST UPSLOPE DEVELOPS TONIGHT. WITH MODEL SOLUTIONS STARTING TO INDICATE THE POSSIBILITY OF ADVISORY LEVEL WINDS DEVELOPING ACROSS THE SANTA MONICA RANGE AND THE LOS ANGELES AND VENTURA COUNTY MOUNTAINS AN ADVISORY WAS ADDED. LOCAL 4-KM WRF AND NAM-WRF SOLUTIONS SUGGEST 25 TO 30 KNOTS OF NORTHEAST WINDS IN THE BOUNDARY LAYER...950 MB...AND 850 MB. THE THERMAL SUPPORT WILL REMAIN MARGINAL...BUT COULD INTENSIFY IN THE WRAP AROUND PATTERN. && .PREV DISCUSSION... SHORT TERM...AS THE LOW MOVES AND INTENSIFIES THROUGH TOMORROW...IT WILL MOVE INTO BAJA AND OUT OF OUR WEATHER PICTURE ON WEDNESDAY. WHILE THERE IS A CHANCE OF A LIGHT SHOWER ON THE BACKSIDE OF THE LA MTNS EARLY WEDNESDAY WITH MOIST EAST FLOW...BY WEDNESDAY AFTERNOON DRY NORTHEAST FLOW AND A QUICKLY BUILDING RIDGE WILL PUSH TEMPERATURES BACK TOWARD NORMAL WITH CLEARING SKIES. THIS TREND WILL CONTINUE THURSDAY AND FRIDAY...WITH BREEZY NORTHEAST WINDS AND TEMPERATURES INTO THE 70S TO LOWER 80S OVER ALL COASTAL AND VALLEY SPOTS. WHILE THE WINDS ON THURSDAY LOOK THE STRONGEST...THEY DO NOT LOOK STRONG ENOUGH TO WARRANT AN ADVISORY AT THIS POINT. LASTLY...A LARGE WEST SWELL TRAILING BEHIND OUR CURRENT SYSTEM WILL BRING HIGH SURF TO THE AREA WEDNESDAY AND THURSDAY. LONG TERM...THE RIDGE OVER THE AREA ON FRIDAY WILL BREAK DOWN OVER THE WEEKEND...AS A FEW TROUGHS MOVE THROUGH THE REGION INTO EARLY NEXT WEEK. WHILE CURRENT PROJECTIONS KEEP THEM ALL TO THE EAST...THERE IS ENOUGH OF A SPREAD IN THE ENSEMBLE SOLUTIONS TO PROVIDE A GLIMMER OF SLIM HOPE FOR RAIN...ESPECIALLY SUNDAY AND MONDAY. WITH THAT SAID...THE WAY THIS WINTER HAS BEEN GOING...WILL BE KEEPING MOST OF THE CHIPS IN THE DRY BIN. EITHER WAY...WE LOOK TO HAVE A COOLING TREND OVER THE WEEKEND THAT SHOULD EXTEND INTO NEXT WEEK WITH A FEW CLOUDS TO DOT THE SKY. IF THESE SYSTEMS KEEP THEIR INSIDE TRACK...GUSTY NORTHERLY WINDS WILL HAVE TO BE DEALT WITH AS WELL. && .AVIATION...08/0520Z... UPPER LOW WILL CONTINUE TO SPIN OFF THE COAST OVERNIGHT...ALLOWING FOR SOME LIGHT SHOWERS TO CONTINUE TO WRAP AROUND THE AREA. AT THIS TIME...EXPECT ANY CIGS TO REMAIN AT VFR LEVELS. THERE IS THE POSSIBILITY OF SOME MVFR VSBYS ACROSS INTERIOR SECTIONS INCLUDING KPRB. DEVELOPING NORTHEAST WINDS OVERNIGHT MAY PRODUCE SOME LLWS AND TURBULENCE ISSUES THROUGH THE PASSES AND CANYONS. KLAX...HIGH CONFIDENCE IN 06Z TAF. THERE IS A 20% CHANCE OF MVFR CIGS AND/OR VSBYS BETWEEN 10Z AND 18Z. CURRENT EAST WINDS ARE EXPECTED TO REMAIN AT OR BELOW 7 KNOTS THROUGH WEDNESDAY MORNING. KBUR...HIGH CONFIDENCE IN 06Z TAF. THERE IS A 20% CHANCE OF MVFR CIGS AND/OR VSBYS BETWEEN 10Z AND 18Z. && .LOX WATCHES/WARNINGS/ADVISORIES... WIND ADVISORY (SEE LAXNPWLOX). SMALL CRAFT ADVISORY (SEE LAXMWWLOX). MARINE WEATHER STATEMENT (SEE LAXMWSLOX). && $$ PUBLIC...HALL/KITTELL AVIATION...RAT SYNOPSIS...SETO/HALL WWW.WEATHER.GOV/LOSANGELES
NWS LOX Office Area Forecast Discussion
Glendora Random Weather Fact
HUMIDEX
Definition Humidex - Over the years, several measures have been proposed to relate various combinations of temperature and humidity into a single number to approximate what hot, humid weather feels like to the average person. Of these, humidex is the one most familiar to Canadians. Humidex was introduced into Canada in 1965. The index is a summer analogue of the wind chill factor in that it is an equivalent air temperature. Air of a given temperature and humidity is equated in comfort to air of a higher temperature that has a negligible moisture content. Comfort is quite subjective and largely dependent on the age and health of the individual. Weather conditions causing prickly heat in an infant may result in heat cramps in a teenager, heat exhaustion in a middle-aged and heat stroke in a senior. Humidex is also limited as an overall hot-weather comfort index because it does not consider other factors such as pressure, wind speed, precipitation, sunshine or pollen.
