CalNex Forecast

Prepared Saturday

29 May 2010

Anticipated Platform Activities

WP-3D Saturday: evening-night flight, 7 pm takeoff   Sunday: night-early am flight, 10 PM takeoff NOAA Twin Otter:        CIRPAS Twin Otter:   NASA King Air:   R/V Atlantis:     Saturday: LA bight, Sat am off Palos Verdes 

Local Features Saturday night:  Build up of concentrations in Southern SJV and LA Basin for contrast of emission mixes and chemistry, weak outflow from SJV to SE deserts;  LA bight contrast in marine layer vs 700mb trajectories and concentrations, see winds at 700 mb & sfc and LA plume at 4 sigma levels. Ozone 1,600' elev. Catalina Isle: http://tbsys.serveftp.net/Catalina/    Sunday night:  Continued stagnation Sun am, but pm sea breeze will reestablish. Similar Sun night target in LA bight as on SatContrast of chemical compositions for late Sunday (e.g., 23 PDT -  COAMPS) outflows from SJV and LA Basin into E Deserts  Early Next week: Weak trough.   Late Next week: Uncertain as GFS predicts 500 mb ridge builds but ECMWF predicts continued influence from a somewhat deeper and slower trough with zonal flow through Thursday.

Synoptic Overview for California

Saturday May 29•    High Pressure Ridge building over the west•    Transport flow turns more Northwesterly •    Strong northwesterly surface gradients in the N. CA•    Strong Offshore gradients for SoCal coast Sunday May 30•    Ridge flattens as weak trof approaches from the north•    Westerly transport flow•    Weaker surface onshore flow in north weaker offshore in south

Monday May 31 •    Weak PacNW trough over N CA•    Transport flow turns W/SW

Tuesday June 1 •    Zonal flow•    Transport flow turns W/NW

Analysis – 00Z Friday

Analysis - 00Z Saturday

12 hour - 12Z Saturday

24 hour - 00Z Sunday

36 hour - 12Z Sunday

48 hour - 00Z Monday

60 hour – 12 Z Monday

3 day – 00Z Tuesday

3 day – 00Z Tuesday

GFS

ECMWF

4 day – 00 Z Wednesday

GFS

ECMWF

5 day – 00 Z Thursday

ECMWF

GFS

6 day – 00z Friday

GFS

ECMWF

Large Scale Transport

RAQMS FX updated Sat, May 29th

San Joaquin Valley

Saturday May 29Surface Winds: The surface observations this morning show NW flow in the northern and central SJV, with stronger conditions in the north, and variable conditions in the southern SJV. The wind profilers in the SJV show the same NW conditions above the surface, except for Tracy which shows a S flow. CANSAC shows NW flow in the northern SJV as well as the west side of the Valley, with calmer conditions in the central and south. Wind flow decreases as the day progresses. A light outflow out of the southern SJV via Tehachapi pass is predicted by the evening.Boundary Layer Mixing: The wind profilers indicate a slight to no temperature inversion across the SJV. CANSAC indicates that mixing should improve to 3,500 feet throughout most portions of the SJV by the afternoon.Air Quality: Good to Moderate air quality is expected across the SJV.Sunday May 30Surface Winds: CANSAC shows typical downsloping into the SJV off of the Sierras in the early morning hours due to more stable conditions. Light NW flow expected throughout the SJV as the day progresses. Evening hours again shows a light outflow out of the southern SJV via Tehachapi pass.Boundary Layer Mixing: CANSAC shows that mixing conditions slightly worse than Saturday, with an improvement up to 2,500 feet across most parts of the SJV.Air Quality: Moderate air quality is expected across most of the SJV, with possible USG.

San Joaquin Valley

Monday May 31Surface Winds: CANSAC shows typical inflow into the SJV via Altamont and Pacheco Passes, with NW flow increasing slightly as the day progresses. Dowsloping in the morning is not projected to be as pronounced as it was for early Sunday morning.Boundary Layer Mixing: CANSAC shows that mixing should improve to 3,500 feet throughout most of the SJV by the afternoon.Air Quality: Expected to be mostly Moderate throughout the SJV, with possible USG.

Tuesday and Wednesday June 1-2Surface Winds: GFS shows surface winds to be predominately from the NW, with a weak trough moving through the area on Tuesday. Boundary Layer Mixing: Mixing conditions should improve on Tuesday due to passing system, but stabilize again starting on Wednesday forward.Air Quality: Expected to be mostly Moderate throughout the SJV, with air quality deteriorating towards the end of the week. This could result in the first major ozone episode for the SJV this year.

*Potential Targets for next Flight Day*For Saturday or Sunday evenings, the air exchange from the southern SJV into the Kern desert over the Tehachapi Pass might be a good feature to capture.

Southern Coastal Waters

OLD Friday's FCST South Coast•  Friday:  Upper low moves over Great Basin; AM Miramar sounding shows

deep moist layer to ~5000 feet; low clouds hugging the mountains this AM, but mostly clear otherwise; drier NW flow will start late Thursday night & Friday; warming starts, but only a few degrees higher; clouds decrease for mostly sunny afternoon; some gusty NW winds through day; northerly surface gradients peak Friday night for strong winds on Central Coast, Santa Ynez range, Antelope Valley & I-5 corridor & some in San Fernando & Santa Clarita Valleys;  Moderate Ozone

• Saturday:  some weak ridging (really just weaker trough) aloft over So. Cal.; clear skies; northeasterly (offshore) surface gradients; warming 10-15 degrees for above normal temps - near 90 degrees F in warmer valleys; AQ mostly Moderate, but some USG possible; increased fire hazard with the dry, warm offshore winds

• Catalina Island Ozone Monitoring (elev 1600 ft):  http://tbsys.serveftp.net/Catalina/ 

• Sunday:  warm temperatures continue with weaker northeasterly (offshore) flows in morning; earlier onshore gradients in afternoon will keep temperatures slightly cooler than Saturday, especially at near coast but still warm inland; more stratus/marine layer may return to coast Sunday night/Monday AM with AM coastal eddy likely; USG AQ possible in eastern SoCAB

Northern California

Observed, Model-Interpolated Winds for SF Bay http://sfports.wr.usgs.gov/cgi-bin/wind/windbin.cgi

and COAMPS Wind Plots

http://www.sccoos.org/data/coamps/coamps.html