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Wind Observations

Pacific Northwest Pressure Gradients

TTAA00 KSEW 222215
** SEW GRADIENT TABLE 11/22/09 22Z **                              222215Z

       UIL-  OTH-  PDX-  OLM-  UIL-  HQM-  AST-  BLI-  UKI-  AST-  BLI-  BLI-
DD/HH  BLI   SEA   BLI   BLI   NUW   SEA   UIL   YZT   UIL   SEA   YQQ   YWL 
22/22  +2.4 +10.5  +7.7  +4.2  +1.5  +2.2  +4.7   0.0  +7.6  +4.6  +1.2  +4.6
22/20  +2.4 +13.2  +9.0  +4.5  +1.7  +2.5  +5.4  -0.5 +11.3  +5.4  +0.9  +3.5
22/18  +2.4 +15.8  +9.6  +3.6  +2.3  +3.3  +5.7  -0.4 +14.8  +6.7  -0.2  +1.3
22/16  +1.3 +19.3  +9.1  +1.4  +1.6  +3.8  +6.6  -0.3 +18.2  +8.2  -0.8  -1.2
22/14  +1.3 +21.9  +8.7  -2.6  +1.1  +2.5  +4.9  -1.5 +21.7  +7.1  -2.3  -4.4
22/12  -1.5 +21.0  +6.0  -2.5  -0.4  -4.2  +2.5  -0.5 +26.3  +2.5  -1.8  -5.4
22/10  -6.4 +16.1  +0.5  -2.5  -5.5  -4.6  -0.3  +2.2 +30.5  -5.4  -0.3  -4.5
22/08  -6.7  +6.5  -0.9  -2.5  -5.5  -4.9  +0.6  +5.9 +27.5  -5.3  +2.4  -2.9
22/06  -6.6  +1.3  +0.9  -0.7  -5.9  -4.9  +1.8  +9.5 +23.6  -5.5  +5.1  -0.3
22/04  -5.1  +1.1  +3.8  +1.2  -5.1  -3.5  +3.3 +10.7 +19.2  -4.1  +5.8  -0.1
22/02  -3.9  +2.9  +5.2  +1.8  -3.9  -2.8  +4.6 +10.3 +16.4  -2.5  +4.7  -0.3
22/00  -4.3  +4.4  +4.1  +0.8  -3.5  -2.2  +4.9 +10.0 +14.1  -1.1  +4.5  +1.3
21/22  -4.8  +4.4  +3.3  +0.2  -3.8  -2.4  +4.2  +9.6 +11.9  -1.6  +4.4  +3.6

       PDX-  UIL-  CLM-  SEA-  SEA-  OLM-  SEA-  YKM-  SHN-  SHN-  SEA-  SMP-
DD/HH  DLS   CLM   NUW   EAT   YKM   YKM   GEG   GEG   SEA   NUW   SMP   EAT 
22/22  +4.1  +2.2  -0.7  +4.4  +3.2  +4.9  +5.9  +2.7  +0.4  +2.0  +4.4   0.0
22/20  +5.2  +2.0  -0.3  +4.3  +3.2  +5.3  +5.0  +1.8  -0.1  +1.6  +4.4  -0.1
22/18  +5.4  +2.0  +0.3  +2.2  +1.9  +4.1  +1.5  -0.4   0.0  +1.3  +3.4  -1.2
22/16  +4.3  +1.2  +0.4  -0.7   0.0  +1.7  -3.5  -3.5  -0.2  -0.2  +1.6  -2.3
22/14  +2.2  +1.5  -0.4  -5.4  -4.1  -5.8  -9.1  -5.0  -1.6  -2.7  -1.0  -4.4
22/12  +0.2  +2.1  -2.5  -9.0  -7.3  -8.3 -11.0  -3.7  -1.0  -1.4  -2.8  -6.2
22/10  -4.7  -1.9  -3.6  -8.8  -8.7  -9.9 -12.8  -4.1  -1.4  -1.8  -3.5  -5.3
22/08  -6.6  -1.7  -3.8  -7.5  -6.4  -8.1 -12.3  -5.9  -1.2  -0.8  -2.4  -5.1
22/06  -4.2  -1.9  -4.0  -4.6  -4.9  -6.3  -9.7  -4.8  -1.5  -0.1  -0.9  -3.7
22/04  -2.2  -1.4  -3.7  -2.7  -4.4  -5.5  -6.8  -2.4  -1.5  +0.8  -0.4  -2.3
22/02  -1.7  -1.1  -2.8  -1.5  -3.7  -5.1  -5.7  -2.0  -1.6  +1.6  -0.2  -1.3
22/00  -1.6  -1.0  -2.5  -1.7  -2.9  -3.8  -4.9  -2.0  -1.1  +1.4  -0.5  -1.2
21/22  -1.0  -1.6  -2.2  +0.3  -1.3  -2.1  -1.9  -0.6  -1.3  +0.7  +0.7  -0.4

 
 Rules of thumb for estimating wind speed and direction based on local pressure gradients:
  (UIL-BLI) x 10 = Use if gradient is positive. Results in west wind thru the Strait of Juan De Fuca.
  (UIL-BLI) x 5 = Use if gradient is negative. Results in east wind thru the Strait.

  (OTH-SEA)

= South wind at SEA if gradient is positive. North wind if gradient is negative.
  (PDX-BLI) x 5 =

South wind at SEA if gradient positive. North wind if gradient negative.

  (OLM-BLI) x 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.
 Show Decoded Data Show METAR/TAF 
KSEA   22 Nov 2:53 pm
Temperature47°F
Dew Point38°F
Ceiling (×100ft)024
Visibility10sm
Weather-
Altimeter29.94"Hg
Wind230° / 15g28kt
KSEA  METAR
KSEA 222253Z 23015G24KT 10SM BKN024 BKN060 08/03 A2994 AO2 PK WND 23027/2230 SLP147 T00830033
KSEA  TAF
KSEA 222107Z 2221/2324 24015G25KT P6SM BKN020 BKN050
    TEMPO 2221/2224 OVC020
  FM230000 24011KT P6SM SCT020 BKN050
  FM230600 19006KT P6SM SCT090 BKN200
  FM231200 18006KT P6SM BKN090 OVC150
  FM232000 18010KT P6SM -RA OVC030

SEA TRACON WEATHER IMPACTS
ISSUED: 11/22/2009 2:01:36 PM  
PSCZ CONF TIME WIND SHIFT INFO
BFI      
SEA      
WIND (>40KT AOB 050) DIR/SPD/LEVEL
SEA      
TS (WITHIN 10 MILES)
BFI    
SEA    
FOG (VIS < 1 MILE)
BFI    
SEA    
  

ZSE ARTCC PIREP REQUIREMENTS

Issued: 11/22/2009 2:01:39 PM

AREAS

HAZARDS    A       B       C       D   
ICING X X X  
LO-TURB X X X X
LLWS        
HI-TURB X X X X
TSTM        
CIG <050 X X X X
IFR     X  

Click here for ZSE Area Map


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