IFR Verification

As a follow-up to yesterday's post concerning probabilistic flight rule prediction, here are some quick verification images.  For the C&V prediction, the forecast period is 21Z - 09Z.

Each image contains the METAR observations of flight category overlaid on the gridded data set.  The first gridded data set is an analysis of observed ceiling and visibility conditions, the National Ceiling and Visibility Analysis (NCVA).  Hourly data is show along with the METARs that went into this analysis.

NCVA Field and METAR flight category for 21Z 11 Feb - 09Z 12 Feb.

The primary forecast concern in this area was the lifting of the ceilings, bringing terminals out of IFR conditions.  The dataset shown below is the GFS-LAMP IFR conditions.  Regions shaded in green are where the 18Z GFS-LAMP run from 11 Feb is predicting IFR conditions.  It clears the IFR conditions fairly well in PA/NJ/NY/CT, but keeps DL/MD/VA in IFR conditions too long.

11 Feb 18Z GFS-LAMP forecast valid same period as NCVA.

Additionally, the SREF and AFWA probability of flight category as highlighted in yesterday's post is show below.  The SREF is the 09Z run from Feb 11, and the AFWA is the 00Z run from the same day.  Only the MVFR and IFR conditions are shown in each of these products. The SREF forecast does not seem to discriminate well between MVFR and IFR conditions (all or nothing) and clears the IFR conditions along the northeast coast fairly well.  The AFWA forecast tends to clear the IFR conditions to quickly along the northeast coast.

Another feature of both of these forecast is the forecast areas of IFR around the Great Lakes region that did not verify.  MVFR conditions were observed in MI and NWRN OH.  In the SREF this area is especially overdone and we are again seeing the issues that the SREF has discriminating between MFVR and IFR conditions.  The are in the AFWA is also overdone, with IFR conditions forecast in PA where only MVFR was observed.

11 Feb 09Z SREF forecast valid same period as NCVA.

11 Feb 00Z AFWA forecast valid same period as NCVA.