Rules of thumb to inerpret these.   Seattle Pilots Briefing Page
TTAA00KSEW291215        
**SEWGRADIENTTABLE11/29/0912Z**291215Z    
          
 UIL-OTH-PDX-OLM-UIL-HQM-AST-BLI-UKI-AST-BLI-BLI-
DD/HHBLISEABLIBLINUWSEAUILYZTUILSEAYQQYWL
29/12-0.2+1.2+2.9+1.5-0.9-0.1+2.2+7.0-7.2+0.5+3.1+8.6
29/10-0.4+1.2+3.1+1.9-0.3-0.6+2.6+6.9-7.2+0.3+3.2+8.7
29/08+0.1+2.0+3.1+1.3-0.1+0.1+1.8+7.1-7.7+0.6+2.9+9.0
29/06-0.5+1.4+3.4+2.2-1.0-0.7+2.8+7.0-6.7+0.1+2.6+8.9
29/04-0.2+2.0+3.6+2.0-0.6-0.3+2.6+7.2-7.0+0.5+2.6+8.3
29/02-0.2+2.3+3.8+2.2-0.8+0.1+2.9+6.2-8.0+0.9+2.3+8.1
29/000.0+2.4+3.9+2.4-0.4+0.4+2.5+6.0-8.6+0.7+2.7+8.2
28/22-0.2+2.2+3.8+1.9-0.7-0.1+2.8+6.3-8.7+0.7+3.4+8.4
28/20+0.3+2.9+4.9+2.8-0.5-0.4+3.2+7.0-8.1+1.0+3.7+8.4
28/18-0.2+3.2+4.9+2.6-0.6-0.3+3.4+7.8-6.9+0.7+3.8+8.3
28/16-0.1+3.4+5.0+2.9-0.7-0.2+3.4+7.7-6.6+0.7+4.0+6.4
28/14-0.7+3.0+3.9+2.3-0.9-0.4+3.2+8.4-7.3+0.5+4.5+5.8
28/12-0.2+3.1+3.7+2.2-0.6-0.4+3.0+7.9-7.9+0.7+3.5+4.8
          
 PDX-UIL-CLM-SEA-SEA-OLM-SEA-YKM-SHN-SHN-SEA-SMP-
DD/HHDLSCLMNUWEATYKMYKMGEGGEGSEANUWSMPEAT
29/12+1.1+0.1-1.0+2.3+0.5+0.5+0.7+0.2-1.1-0.3+1.3+1.0
29/10+1.7+0.6-0.9+2.8+0.9+0.9+1.7+0.8-1.2+0.8+1.7+1.1
29/08+1.4+0.5-0.6+2.7+0.2+0.2+1.3+1.1-1.0+0.1+1.7+1.0
29/06+1.7+0.3-1.3+3.7+0.8+0.8+2.2+1.4-1.4+0.3+1.5+2.2
29/04+1.8+0.2-0.8+2.8+0.5+0.6+1.9+1.4-1.2+0.3+1.5+1.3
29/02+2.1+0.3-1.1+2.4+0.2+0.6+1.2+1.0-0.8+0.4+1.8+0.6
29/00+2.1+0.6-1.0+2.4+0.2+0.8+0.9+0.7-0.8+0.6+1.4+1.0
28/22+2.3+0.4-1.1+2.1+0.5+0.5+1.0+0.5-1.1+0.3+1.4+0.7
28/20+2.3+0.7-1.2+2.3+0.1+0.4+1.6+1.5-1.2+0.5+1.8+0.5
28/18+1.8+0.7-1.3+2.0-0.3-0.2+1.3+1.6-1.1+1.0+1.3+0.7
28/16+1.9+0.5-1.2+2.5+0.1+0.4+1.1+1.0-1.2+0.8+1.8+0.7
28/14+2.3+0.2-1.1+3.1+1.0+1.3+1.9+0.9-1.1+0.7+2.1+1.0
28/12+2.2+0.4-1.0+3.9+1.7+1.8+2.3+0.6-1.0+0.7+2.1+1.8
          

Rules of thumb for estimating wind speed and direction based on local pressure gradients:
(UIL-BLI) * 10 	= 	West wind in Strait of Juan De Fuca if gradient is positive
(UIL-BLI) * 5 	= 	East wind in Strait of Juan De Fuca if gradient is negative
(OTH-SEA)	= 	South wind at SEA if gradient is positive. North wind if gradient is negative.
(PDX-BLI) * 5 	= 	South wind at SEA if gradient positive. North wind if gradient negative.
(OLM-BLI) * 10	= 	South wind at SEA if gradient positive. North wind if gradient negative.
(SEA-EAT) 	= 	Westerly component at SEA if gradient positive. Easterly if gradient negative.
(SEA-GEG) 	= 	Westerly component at SEA if gradient positive. Easterly if gradient negative.
(SEA-SMP) 	= 	Westerly component at SEA if gradient positive. Easterly if gradient negative.
transpose
Pressure gradients from regional airports. Large numbers indicate strong winds from high to low pressure.
So when UIL-NUW Quillayute — Whidbey NAS is a large positive number, expect strong West winds in the Strait of Juan de Fuca. 

Washington Airports and other NWS stations
                                            elevations in meters 
                              N       W      elev 
WA ARLINGTON MUNI   KAWO    48 10N  122 10W   42 
WA BELLINGHAM       KBLI    48 48N  122 32W   50 
WA WHATCOM (BLI)    KHUH    48 57N  122 35W   26 
WA BREMERTON NTNL   KPWT    47 30N  122 45W  147 
WA BURLINGTON/MT V  KBVS    48 28N  122 25W   43 
WA CHEHALIS CENTRAL KCLS    46 41N  122 59W   54 
WA COLVILLE MUNICIP KCQV    48 32N  117 52W  572 
WA DEER PARK        KDEW    47 58N  117 26W  668 
WA EASTSOUND/ORCAS  KORS    48 42N  122 54W    8 
WA ELLENSBURG       KELN    47 02N  120 32W  519 
WA EPHRATA          KEPH    47 18N  119 31W  383 
WA EVERETT          KPAE    47 55N  122 17W  180 
WA FAIRCHILD AFB    KSKA    47 37N  117 39W  750 
WA FORT LEWIS/GRAY  KGRF    47 04N  122 34W   92 
WA FRIDAY HARBOR    KFHR    48 31N  123 02W   32 
WA HANFORD          KHMS    46 34N  119 35W  223 
WA HOQUIAM          KHQM    46 58N  123 56W    7 
WA KELSO LONGVEIW   KKLS    46 07N  122 54W    5 
WA MOSES LAKE       KMWH    47 12N  119 19W  362 
WA OAK HARBOR AIRPA K76S    48 15N  122 40W   58 
WA OLYMPIA          KOLM    46 58N  122 54W   58 
WA OMAK             KOMK    48 28N  119 31W  395 
WA PASCO            KPSC    46 16N  119 07W  121 
WA PORT ANGELES     KCLM    48 07N  123 30W   85 
WA PULLMAN/MOSCOW   KPUW    46 45N  117 07W  773 
WA PUYALLOP/THUN    KPLU    47 06N  122 17W  164 
WA QUILLAYUTE       KUIL    47 56N  124 33W   54 
WA RENTON           KRNT    47 30N  122 13W   21 
WA SEATTLE/BOEING   KBFI    47 33N  122 19W    4 
WA SEATTLE/METRO    KSEA    47 27N  122 19W  136 
WA SEATTLE/WFO      KSEW    47 27N  122 18W  130 
WA SEATTLE/ARTCC    KZSE    47 17N  122 11W   99 
WA SEATTLE/CAMANO I KATX    48 12N  122 30W  151 
WA SHELTON          KSHN    47 14N  123 08W   82 
WA SPOKANE          KOTX    47 41N  117 38W  727 
WA SPOKANE/FELTS    KSFF    47 41N  117 19W  609 
WA SPOKANE/METRO    KGEG    47 37N  117 32W  735 
WA STAMPEDE PASS    KSMP    47 17N  121 20W 1208 
WA TACOMA           KTIW    47 16N  122 35W   89 
WA TACOMA/MC CHORD  KTCM    47 07N  122 28W   98 
WA TATOOSH/VOR      KTOU    48 18N  124 38W  520 
WA TOLEDO WINLOCK M KTDO    46 28N  122 47W  113 
WA VANCOUVER        KVUO    45 37N  122 39W    8 
WA WALLA WALLA      KALW    46 06N  118 17W  363 
WA WENATCHEE        KEAT    47 24N  120 12W  377 
WA WHIDBEY IS. NAS  KNUW    48 21N  122 39W   14 
WA YAKIMA           KYKM    46 34N  120 32W  324 
WA BURLINGTON/MT V  K75S    48 28N  122 25W   43 
WA COLVILLE         K63S    48 32N  117 52W  571 
WA DEER PARK        K07S    47 58N  117 26W  668 
WA DESTRUCTION ISL          47 40N  124 31W   21 
WA PORT ANGELES CG  KNOW    48 08N  123 25W    4 
WA SMITH ISLAND             48 19N  122 10W   15 
WA PEARSON/VANCOUVR K60S    45 37N  122 39W    8 
WA WEST POINT (LS)          47 40N  122 34W    3 
BC ABBOTSFORD AIRPO CYXX    49 01N  122 22W   58 
BC AGASSIZ (AUTO)   CWZA    49 15N  121 46W   15 
BC ENTRANCE IL AUTO CWEL    49 13N  123 47W    5 
BC ESQUIMALT METOC  CWPF    48 25N  123 25W   12 
BC HOPE AIRPORT (MA CYHE    49 22N  121 28W   39 
BC HOPE SLIDE       CWKV    49 16N  121 13W  674 
BC KELP REEFS       CWZO    48 33N  123 14W    1 
BC MALAHAT (AUTOB)  CWKH    48 34N  123 34W  366 
BC MERRY ISLAND     CWMR    49 28N  123 55W    8 
BC MT SICKER RADAR  CXSI    48 51N  123 45W    1 
BC NANAIMO AIRPORT  CYCD    49 02N  123 52W   28 
BC P. MEADOWS CS AU CWMM    49 12N  122 40W    5 
BC RACE ROCKS AUTOB CWQK    48 17N  123 31W    5 
BC SAND HEADS (LS)  CWVF    49 06N  123 18W    1 
BC SATURNA ISL (MAP CWEZ    48 46N  123 02W    7 
BC SHERINGHAM AUTOB CWSP    48 22N  123 55W   21 
BC SQUAMISH (AUTOB) CWSK    49 46N  123 10W   60 
BC VANCOUVER (AUTOB CWHC    49 17N  123 07W    2 
BC VANCOUVER INTL A CYVR    49 10N  123 10W    2 
BC VIC. HARTLAND AU CWVV    48 31N  123 28W   49 
BC VICTORIA (AUTOB) CWLM    48 25N  123 19W   70 
BC VICTORIA HARBOUR CYWH    48 25N  123 23W   10 
BC VICTORIA INTL AR CYYJ    48 38N  123 25W   19 
BC VICTORIA UNIV    CWYJ    48 28N  123 18W   39 
BC W VANCOUVER AUTO CWWA    49 21N  123 10W  178 
BC WHITE ROCK AUTOB CWWK    49 01N  122 46W   15