WEATHER
DATA & IMAGERY:
Current Weather WA/OR
– Listed North to
South Map
of Weather WA/OR
Current Weather California – Listed North to South
Map
of Weather California
Weather Stations>>> California North Bay Area Pacific Northwest Mid Columbia
Evapotranspiration Links>>> East
Delta Area Elsewhere
California
Pressure Gradients – (SFO-ACV) for Napa N/S gradient and (SFO-SAC) E/W gradient
Positive numbers are on shore flow and
negative numbers are off shore flow.
(SMX-BFL) for the South-Central Coast
forecast. Positive is on shore, and
negative is off shore.
Compare with conditions the day before to
make judgements on how temps will change.
Most useful during
the warm season (May-October) to determine on shore and off shore flow.
Compare to the
previous day to determine the trend to help with current day temp
forecasts
(SMX-BFL) for on shore flow South Central
Coast
North Bay Profiler – Best tool to determine
depth of marine layer & lower atmosphere winds.
Central Coast Santa Barbara California
Roundup – Use this to map out the pressure gradients
Calif
Rain past 24 hours – Good information to use in the Summary/discussion area.
Current
SST – North Bay Area – To be entered on the climate section of the Napa/Sonoma page
Northwest Radar NWS
Radar – zoom
in anywhere and loop
Northwest
Sat Loop West
Coast Sat Loop California
Sat Loop East
Pacific Sat Loop
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FORECAST
MODELS & DATA:
4 Panel GFS Loop>>> 00Z Run 06Z Run 12Z Run 18Z Run (06Z for morning forecasts)
4 Panel Canadian>>> 00Z Run 12Z Run (00Z for morning forecasts)
Alternate Sites>>> All Forecast Models West Coast-GFS GFS-240
hours NAM-84
hours
HRRR NW Loop
- (12Z morning
forecast) HRRR SW Loop
- (12Z morning
forecast)
Northwest
Models>>> MM5 4km Loop
Cloudiness Loop GFS-Extended
Soundings
Windy
Forecast model – Great for looking and wind patterns
10
Day GFS Overview 10
Day EUROPEAN Overview (Compare them for 6-10 day outlook)
MOS STATIONS – Use NAM MOS (short range) &
EXTENDED GFS MOS (Out to 7 days)
Click on map for stations or enter
the station identifier below in the box and hit return
How
to read MOS –
What do all the numbers mean?
Cooperative
Station MOS – Scroll
down to ANGC1
(Angwin/Howell Mountain)
The last 2 letters are the state
(California is C1) organized alphabetically. First 3 letters ANG
The data is 7 days max/min temps
based on GFS MOS
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NWS
FORECAST LINKS:
FP3 Discussions>>> Seattle Portland Napa/Sonoma South Coast Sacramento Hanford
(Read these discussions to
see what the NWS forecaster is thinking)
Zone Forecasts>>> Seattle Portland Central
Coast N&C
Calif SJ-Valley SW-Calif South-Cal
(If you want to see what the NWS zone
forecasts are for these areas)
North
Bay Forecast (Look at this to see the
NWS forecast for the area)
San
Luis Obispo Forecast Santa
Maria Forecast Santa
Ynez Forecast
Long Range forecasts: Climate Prediction Center (6-10 day, 8-15 day, 3-4 week,
monthly)
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WEATHER
UNDERGROUND FORECASTS:
(These are 10 day & hourly
forecasts for each of the areas we forecast for)
For the Puget Sound and
Portland forecasts each city listed represents one of the forecast zones.
Puget Sound Area>>> Bellingham Pt Townsend Everett Seattle Fall City Olympia
Portland & WV>>> Kelso Portland Salem Eugene
North Bay Area>>> Santa Rosa – Compare to STS MOS middle
range temperatures
Petaluma
– Represents
lower end of the daytime temperature range
St
Helena – Represents warmer areas in the North Bay during the day.
MOS is better for the
minimum temperature forecasting in the North Bay Area
Sacramento Valley>>> North Sac Valley South Sac
Valley
San Joaquin Valley>>> East Delta North-SJV Central SJV South-SJV
South Central Coast>>> Coastal
valleys Santa
Ynez Valley (Both areas in the forecast)
These forecasts are a great source for the 6-10 day portion of your California forecast zones
Chelan PUD>>> (EAT)
Wenatchee Daily-Weather Alternate Chelan PUD web page
Mid Columbia Region>> Hood River The Dalles H-River
NWS-MOS The
Dalles NWS-MOS
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1.
Collect weather data from stations and fill in the table. (Some links are just one
click and you see the data. Others you
click, scroll down to the max, min table for today’s low. Then hit the blue “Previous” arrow and it will quickly
take you do the previous day)
2.
Collect MOS data needed for the areas you are forecasting
for. Cut & past to a notepad
3.
Use 4 panel forecast model to create your forecast, using MOS as
a tool for forecasting max and min temps, dew points, chance of rain. You
can also look at the MOS for winds, but once you have some experience you won't
need MOS as much for wind forecasting.
4.
You can fine tune the shorter-range forecast by looking at the
models below:
MM5 for Puget
Sound and Portland. 4km-WA, and 4km-OR
best for precipitation patterns.
MM5 Cloudiness
loop is very useful for predicting morning low clouds and fog.
GFS-Extended goes out to 180 hours
and covers WA, OR, and northern CA
Also, the HRRR
models are great for seeing precipitation and cloudiness out to 48 hours.
(Washington,
Oregon, and California) Best model for
short term timing of rain in California
5. Once the forecast
is done create a discussion/summary and fill in the individual temperature
forecasts in
the tables.
6.
Take a look at your forecasts to find typos, etc
before sending it out.
MOS Stations used for each forecast: (Stations
listed North to South in each area)
Puget Sound Outlook…. BLI-Bellingham AWO-Arlington SEA-Seattle OLM-Olympia
Portland & Willamette Valley…. KLS-Kelso PDX-Portland SLE-Salem EUG-Eugene
Napa/Sonoma…. UKI-Ukiah STS-Santa
Rosa APC-Napa
South Central Coast….. SBP-San
Luis Obispo SMX-Santa Maria IZA-Santa Ynez
North Sacramento Valley….
RBL-Red Bluff CIC-Chico
South Sacramento Valley….
MYV-Marysville SMF-Sacramento
East Delta…. SMF-Sacramento SCK-Stockton (Use
Stockton for winds)
North SJV…. SCK-Stockton MCE-Merced (Use
Merced for winds)
Central SJV…. MAE-Madera HJO-Hanford
South SJV…. PTV-Porterville BFL-Bakersfield
Columbia Gorge… TTD-Troutdale DLS-The Dalles
Cooperative Stations Gorge…. HOXO3 – Hood River PRKO3 – Parkdale DUFO3 - Dufur
Chelan PUD… EAT-Wenatchee
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RELATIVE HUMIDITY
FORECASTING:
From 100 to 70% humidity it is about 3%
humidity drop for ever degree the temperature dew point spread increases.
Example Temp 50, Dew point 47 would be 100-9% = 91% humidity
From 70 to 50% humidity 2% per degree temp/dew spread.
From 50 to 35% humidity 1.5% per degrees temp dew spread
From 35 to 25% humidity 1% per degrees temp spread.
Same for below 25%
Put another way here is a table of RH and temp/dew point spread
RH
(Temp-Dewpoint)
100% 0 (Zero)
90% 3
degrees
80%
6-7degrees
70% 10
degrees
60% 15
degrees
50% 20
degrees
42% 25
degrees
35% 30
degrees
30% 35
degrees
25% 40
degrees
15% 50
degrees
There are some differences based on the temperatures, but this is
close enough for our purposes.
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EVAPO-TRANSPIRATION FORECASTING:
(April 15 – Oct 31) California zones, except Napa/Sonoma
and South-Central Coast zones
Collect the ET data while collecting
temperature data. There will be a place
in the table.
The most influential factors are
sunshine, winds, and relative humidity, with temperatures being less
impactful. Look at the value range in
your table then evaluate how today’s weather may be different. Most of the Summer skies are clear so the
only thing you have to watch is the winds.
Most days the winds are in the 5-15 mph category. If winds go up a category (5 mph) then add
.05” for your forecast values. So if you are expected 15-30 mph, probably up .10” Same holds true, of course, if you go down a
category from yesterday’s winds.
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GENERAL FORECASTING RANGES & CATEGORIES:
This looks like a lot of stuff at first, but
once you get going it will be second nature to you.
Max Temps ranges 3 or 5 degrees for most forecast areas (55 to 60, or 57 to 60, etc.)
Exceptions: Napa/Sonoma, South Central Coast, Puget
Sound, and Portland forecasts where larger ranges are
more common during in the Summer. Napa
can be 15 degree range on many summer days, but don’t
go over 15 degrees even if you are expected a larger range. Same holds true for Puget Sound forecasts due
to the proximity to the water. If you
are expected 75 at SEA on a summer day your range might be 68 to 75 because
most areas closer to the Puget Sound are cooler. For 2 to 7 day
outlook area you can use larger ranges as necessary.
I like ranges that are 3 degrees, 5
degrees, 7 degrees, 10 degrees, 13 degrees, and 15 degrees.
Ranges are so high on the
South-Central Coast I divide the max temp forecast into two lines on the
forecast during the warm season.
Min Temp ranges, usually 5 degrees for most circumstances
and areas. Occasionally larger ranges in
Napa/Sonoma, Puget Sound, and Portland are necessary due to localized winds and
clear skies.
(You will see my forecasts on the templates and get to know how I handle
these situations.)
Weather: Mostly sunny, partly cloudy,
mostly cloudy, or any combination like party to mostly sunny are good
terms. Also Increasing clouds or
increasing high clouds, or decreasing clouds or clearing skies will work. I am not a fan
of: “a mix of sun and clouds” For the coastal areas during periods
of onshore flow I will commonly say:
Mostly sunny after morning low clouds, or Mostly
sunny after morning fog, or Mostly sunny after areas of morning fog, etc. Also, Mostly sunny
after some morning cloudiness.
Precipitation
Type: Rain, showers, thundershowers,
thunderstorms.
Describers: A chance of rain or showers for a 50% or less
threat. Rain or showers likely for
60-90% threat. Other describers are:
(Isolated showers for 20% or less threat)
(Scattered showers for 30- 60%) (Showers likely for 70-90%) You can go either way you like. Periods of rain 90-100%.
Wind:
I like 10 mph ranges for lower speeds:
Example: North to 10 mph, North 5-15 mph, North 10-20 mph, then 15-25
mph with larger ranges for higher speeds like 15-30 mph, 20-35 mph, 25-40 mph,
etc. If MOS is showing speeds under 5
mph use “up to 10 mph. MOS represents
the average speed so boost the top of the range by 5 mph.
MOS
6-10 mph>>> use 5-15 mph.
MOS
11-14 mph>>> use 10-20 mph
MOS
15-19 mph>>> use 15-25 or 15-30 mph
MOS
20-25 mph>>>use 20-35 mph
MOS
26-30 mph>>>use 25-40 mph
Dew point: 5 degree range most of
the time
Precipitation: To keep it simple, choose from
one of the categories below when forecasting precipitation amounts:
Up to .02” Up to .05” Up to .10” Up to .15” .10 to .25” .15 to .40” .25 to .50”
40 to .75” .50 to 1.00” 75 to 1.50” 1.00 to 2.00” 1.50 to 3.00” 2.00 to 4.00”
Keep in mind that
rainfall amounts on the east side of most of the zones is higher than in the
valleys or general lowlands due to upslope lifting. Amounts are lighter on west side of valleys
due to downslope drying.
This looks like a lot
of stuff at first, but once you get going it will become second nature to you.
