SENIOR DUTY METEOROLOGIST NWS ADMINISTRATIVE MESSAGE
NWS CENTRAL OPERATIONS COLLEGE PARK MD
1546Z TUE NOV 03 2026

...RRFS/REFS NOW OPERATIONAL...
The NWS implemented the Rapid Refresh Forecast System
(RRFS) and RRFS Ensemble Forecast System (REFS) effective
at 12Z this morning, 3 Nov 2026. This major transition
introduces high-resolution convective-scale modeling while
simultaneously retiring a substantial portion of legacy
regional model guidance (including NAM, SREF, HREF, HiResW,
and NAM MOS). See the SCN links below for details.

...ATTN UPPER AIR SITES...
The RRFS observational data ingest window for the 00Z and
12Z RRFS closes around 0051Z and 1251Z respectively,
slightly earlier than the NAM, which incorporated data that
arrived on WCOSS by ~0115Z and 1315Z. Other hourly cycles
have even a tighter window, closing 19 minutes after the
cycle time (i.e. 1319Z for 13Z run). This will be important
for observers to be aware of when launching special
supplemental rawinsonde releases or if a balloon release is
slightly delayed, as you might need to send an initial
round of data messages before the sounding entirely
terminates. The RRFS/REFS data ingest window opens one
hour prior to each hourly run.

* 00Z/12Z...T-1 hr to T+51 min (2300-0051Z and 1100-1251Z)
* 01-11Z and 13-23Z...T-1hr to T+19 min (i.e. 0000-0119Z
for the 01Z run)
* Check receipt of upper air messages at:
https://www.nco.ncep.noaa.gov/status/data/thanks/

Implementation of the Rapid Refresh Forecast System (RRFS)
and RRFS Ensemble Forecast System (REFS):
https://www.weather.gov/media/notification/pdf_2026/scn26-048_Upda
ted_RRFS_and_REFS_Implementation_aad.pdf

Termination of NAM, SREF, HREF, HiresW, and NAM MOS:
https://www.weather.gov/media/notification/pdf_2026/SCN26-47_Updat
ed_Retire_NAM_SREF_HREF_HiresW_NAM_MOS.aab.pdf


SDM/Kempisty/Handel/Kochanowicz