Thursday, December 20, 2007

'49 / '50 Analog on Life Support


Accu-Wx went into a defensive crouch today with a missive by WxMatrix/s Jesse Ferrel where he advanced the arguments 'winter hasn/t started yet' and 'it/s not over...until it/s over'.

Both arguments are silly on their face.

If winter has yet to begin...then why does AW/s Winter Outlook include details about early and mid-DEC. Ferrel then argues their outlook covers NOV through MAR. So which is it?

The 'A forecast hasn/t busted until the event has come and gone' maxim is true altho that/s a mighty thin reed given the current state of winter to date and trends in LR NWP.

Accu-Wx/s Winter '07 / '08 outlook is heavily weighed by the '49 / '50 analog where cold temperatures @ the start of DEC flipped to abnormal warmth mid-month and stayed above normal through FEB.

The time series shows 5H geo-potential heights (left two images) and SLP (right two images) from the pole to 10°N during the first nine days of DEC for 1949 and 2007. Hard to see anything other than weak correlations.

The northern polar stereographic view for the same nine days @ 5H depicts one similar feature...the weak trofs off the west CONUS coast...and several that are at markedly @ odds with each other. Note the analog year trof INVOF the Azores and a ridge in the observed. There/s an analog year trof in the GOM and ridging in the observed. There/s a ridge INVOF the Hawaiian Is. in the analog year and an observed trof.

In the mass fields...both years have HIGH SLP over Siberia...altho it/s much stronger in the analog. Evidence of a GOM LOW in the analog is missing in the observed where a broad area of LOW pressure is centered along the International Date Line.

Not looking too good ATTM for our friends at Accu-Wx. They/ve made a lot of noise and thumped their chests since October hawking the near-certain expectation for a sudden...and dramatic about face in temperatures that would occur mid-DEC. At this point...the '49 / '50 analog might need to be placed on life support.

Calling Doctor Howard...Doctor Fine...Doctor Howard.

Had intended to post the analog / observed comparisons last week...but a good contest snow storm came along...and seeing how that/s the reason why we/re here...it was delayed. Will post an update with a look at the period that/s passed since then.

1 comment:

TQ said...

Funny spelling error in the first line. Should read 'defensive crouch.' Will fix shortly.