Thursday, Sept 13, 2012

A. The pressure change field B. Continuity from the past 6 hours C. The wind gusts in the cold air D. The movement of echoes along the

front E. The speed at which the temp changes

along the front

A. The pressure change field B. Continuity from the past 6 hours C. The wind gusts in the cold air D. The movement of echoes along the

front E. The speed at which the temp changes

along the front

Fall 2012 Contest 1Forecast 5 – Review

Des Moines, IA

Des Moines, IA Forecast

FAA Identifier: DSMLat/Long: 41-32-02.3000N /

093-39-47.1000W41-32.038333N / 093-39.785000W41.5339722 / -93.6630833(estimated)

Elevation: 958 ft. / 292.0 m (surveyed)

Variation: 03E (2000)From city: 3 miles SW of DES

MOINES, IA

KDSM 122354Z 01023G30KT 10SM SCT040 BKN085 OVC150 20/03 A3012 RMK AO2 PK WND

02032/2315 SLP194 60000 T02000033 10300 20200 51023= KDSM 130054Z 02019G30KT 10SM BKN070 OVC085 18/06 A3014 RMK AO2 PK WND 03030/0053 SLP203 T01830061= KDSM 130154Z 01010G21KT 10SM SCT070 BKN080 OVC150 18/08 A3016 RMK AO2 PK

WND 01030/0057 SLP209 T01780078= KDSM 130254Z 02016G22KT 10SM OVC100 17/08 A3016 RMK AO2 SLP207 T01720078

50014= KDSM 130354Z 03022G28KT 10SM SCT100 OVC110 16/09 A3018 RMK AO2 PK WND 02028/0353 SLP214 T01610094= KDSM 130454Z 36011G22KT 10SM BKN019 OVC075 16/11 A3024 RMK AO2 PK WND 02028/0355 RAB30E49 SLP233 P0000 T01560111= KDSM 130531Z 36015G25KT 10SM OVC013 16/12 A3024 RMK AO2= KDSM 130554Z 36016G22KT 10SM OVC009 15/12 A3026 RMK AO2 SLP240 60000

T01500117 10200 20150 403000150 53033= KDSM 130625Z 01016G22KT 7SM -RA BKN011 OVC023 14/12 A3026 RMK AO2 PK WND 03026/0608 RAB01 CIG 009V014 P0003=

KDSM 130554Z 36016G22KT 10SM OVC009 15/12 A3026 RMK AO2 SLP240 60000 T01500117

10200 20150 403000150 53033= KDSM 130625Z 01016G22KT 7SM -RA BKN011 OVC023 14/12 A3026 RMK AO2

PK WND 03026/0608 RAB01 CIG 009V014 P0003= KDSM 130654Z 36015G23KT 8SM -RA SCT011 OVC055 12/10 A3029 RMK AO2 PK

WND 01026/0629 RAB01 SLP251 P0008 T01170100= KDSM 130715Z 01017G24KT 2 1/2SM +RA BR SCT011 BKN023 OVC055 11/09

A3031 RMK AO2 P0004= KDSM 130715Z 01017G24KT 2 1/2SM +RA BR SCT011 BKN023 OVC055

11/09A3031= KDSM 130725Z 03016G27KT 2 1/2SM +RA BR SCT009 BKN031 OVC055 11/09

A3031 RMK AO2 PK WND 03027/0719 P0012= KDSM 130727Z 02018G27KT 3SM RA BR SCT009 BKN022 OVC031 11/09 A3032

RMK AO2 PK WND 03027/0719 P0013= KDSM 130725Z 03016G27KT 2 1/2SM +RA BR SCT009 BKN031 OVC055

11/09A3031= KDSM 130727Z 02018G27KT 3SM RA BR SCT009 BKN022 OVC031 11/09 A3032= KDSM 130754Z 03019G26KT 4SM +RA BR SCT026 OVC050 11/09 A3029 RMK

AO2 PK WND 03027/0719 PRESFR SLP252 P0019 T01060089= KDSM 130854Z 03013G26KT 7SM RA FEW037 BKN060 OVC095 11/08 A3028

RMK AO2 PK WND 04026/0848 SLP252 P0020 60047 T01060083 50008=

Yikes, the effect of evaporational cooling is amplified at night with CAD!

A classic anabatic cold front produces classic effects, sudden drop in temp and all precip behind the front.

Guidance tends to under do a developing anabatic front structure.

The QPF was decent by most models involved since was an increasingly stable environment.