Mary-Beth Schreck, L. David Williams, and Kenneth R. Cook

BUFKIT: Forecasting Wind and Wind Gusts from Momentum Transport Winds

Observed Visibility and Ceiling During Snow

Thunderstorm Climatologies in Various Forms

Fog Climatologies

Observed Visibility and Ceiling During Thunderstorms• Verification Suffers in Summer

Since convective season is when verification suffers (cig/vsby):

Give forecasters some probabilities of occurrence based on climatology

For the 30 year period ending 2006, found all observations with TS for April – August for KRSL, KSLN, KICT, KCNU

From these, found # of occurrences (hours) for each station for the following visibility categories (SM):<0.50.5 – <1.01.0 - <2.02.0 - <3.03.0 – 5.0>5.0

Found % of each category (i.e. How many times does each occur) as % of total of all TSRA Fog obsThese were done for each station for each month

At this point, we have isolated TS obs that contain a MVFR or lower visibility. Using these data we then determined how many of these contained a MVFR or lower ceiling. These were plotted as a percentage of the total

number of TS obs w/ MVFR vsby (i.e. with a ceiling)

Out of these (the ceilings that are below 3000 ft.):Found maximum, minimum, 1st and 3rd

quartiles for each visibility category by station by month.

Plotted results as “box and whiskers” plot

Visibilities gradually increased through the seasonBy July: 75-80% of TS obs had visibilities >5SM.

TS w/ MVFR or lower visibilities that contained a MVFR ceiling also decreased through the season.

By July, it was a statistically “rare” event to have MVFR ceiling and visibility with a thunderstorm.