Tuesday, January 7, 2025

Winter '24 / '25 - Snow Storm #1: Preliminary STP Verification

Smithstonian - 1920s
Preliminary verification of storm-total snowfalls for SUN and MON based on reporting from CDUS41 (CLI) ... CXUS51 (CF6) ... METARs ... and PNS bulletins issued by NWS.

Good coverage and reporting.

Exceptions
SBY
NWS Climatological Report (Daily - CLI) carried 'MM' for SAT snowfall-total and 0.53" liquid.

NWS WFO Monthly/Daily Climate Data (CF6) carried 8.5" and 'M' for liquid.

STP derived by an inverse distance weighting scheme with AKQ and PHI vicinity reports carried in their PNS bulletins for Sussex county ... DE and Worcester and Wicomico counties in MD came to 8.5".

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Stations observing >= Trace:  17 (63%)
Stations observing > Trace:  6 (22%)

Given a station had measurable snowfall; stations observing at least:
4" - 6 (22%)
6" - 5 (19%)
8" - 1 (4%)

MAX snow melt-water (minimum SLR 8:1)
RIC - 1.18"
DCA - 0.81"
IAD - 0.73"

MAX precipitation (frozen + freezing + liquid)
RIC - 1.18"
DCA - 0.81"
IAD - 0.73"

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New daily snowfall record(s)

06-JAN-25
SBY:  8.5"  (4.5"; 1970)
BWI:  6.6"  (3.4"; 1989)
IAD:  6.0"  (4.2; 2015)

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Daily snowfall data table


ORANGE: new daily record
GREY:  STP derived from PNS or METARs or inverse distance weighting

Trace amounts (displayed as 0.05") are not included in STP.

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Areal distribution of storm-total snowfall


Image courtesy NOHRSC
https://www.nohrsc.noaa.gov/

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SFC analysis:  12z ... 06-JAN-25

Image courtesy DOC / NOAA / NWS / NCEP / WPC
https://www.wpc.ncep.noaa.gov/html/avnsfc.shtml

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Please report any errors in Comments along with a link to the correct data.
FINAL results expected NLT WED evening.

4 comments:

TQ said...

apologies for the unzoomable graphics. used a different way to insert the charts. they're not compatible with blogger's 'lightbox' feature.

TQ said...

12z SFC chart when several hours of +SN fell across DMV.

Anonymous said...

RIC later revised down to 3.5

TQ said...

tyvm. will amend the RIC STP.